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    [Low level of 25-OH-vitamin D as a marker of critical ischemia in case of diabetic foot syndrome]. Ignatovich I N,Kondratenko G G,Dobrovol'skaia Iu V Khirurgiia It was done the prospective study of the examination results of 40 patients with diabetes mellitus. All patients were divided into 2 groups for study of 25-OH-vitamin D effect, cholesterol, triglycerides in blood serum on the nature of diabetes mellitus. The first group included patients with ulcero-necrotic injuries in case of neuro-ischemic forms of diabetic foot syndrome. The second group included patients without such injuries. It was significantly determined that there was more neuro-ischemic injuries in case of 25-OH-vitamin D level less than 30 nmol/l. Injuries are connected with reduction of arterial inflow because of osslusive-stenotic lesions of arteries. 25-OH-vitamin D level less than 30 nmol/l is a marker of neuro-ischemic injuries of foot in case of diabetes mellitus. This indication is more specific than cholesterol and triglycerides levels.
    Basal Mitophagy Occurs Independently of PINK1 in Mouse Tissues of High Metabolic Demand. McWilliams Thomas G,Prescott Alan R,Montava-Garriga Lambert,Ball Graeme,Singh François,Barini Erica,Muqit Miratul M K,Brooks Simon P,Ganley Ian G Cell metabolism Dysregulated mitophagy has been linked to Parkinson's disease (PD) due to the role of PTEN-induced kinase 1 (PINK1) in mediating depolarization-induced mitophagy in vitro. Elegant mouse reporters have revealed the pervasive nature of basal mitophagy in vivo, yet the role of PINK1 and tissue metabolic context remains unknown. Using mito-QC, we investigated the contribution of PINK1 to mitophagy in metabolically active tissues. We observed a high degree of mitophagy in neural cells, including PD-relevant mesencephalic dopaminergic neurons and microglia. In all tissues apart from pancreatic islets, loss of Pink1 did not influence basal mitophagy, despite disrupting depolarization-induced Parkin activation. Our findings provide the first in vivo evidence that PINK1 is detectable at basal levels and that basal mammalian mitophagy occurs independently of PINK1. This suggests multiple, yet-to-be-discovered pathways orchestrating mammalian mitochondrial integrity in a context-dependent fashion, and this has profound implications for our molecular understanding of vertebrate mitophagy. 10.1016/j.cmet.2017.12.008
    No Parkin Zone: Mitophagy without Parkin. Villa Elodie,Marchetti Sandrine,Ricci Jean-Ehrland Trends in cell biology Mitochondria are essential highly dynamic organelles that provide the necessary energy for a variety of different processes, such as survival, proliferation, and migration. In order to maintain an intact mitochondrial network, cells have developed quality control systems that allow the removal of damaged or superfluous mitochondria by selective mitochondrial autophagy called mitophagy. Although the parkin/PINK1 axis is often considered the main regulator of mitophagy, a growing body of evidence has shown that this pathway is not unique and that mitophagy can still be functional in the absence of parkin. Here, we will review recent literature describing parkin-independent mitophagy and its role in various physiopathological conditions, therefore representing potential new targets to treat diseases affected by dysregulated mitophagy. 10.1016/j.tcb.2018.07.004
    Evolving and Expanding the Roles of Mitophagy as a Homeostatic and Pathogenic Process. Gustafsson Åsa B,Dorn Gerald W Physiological reviews The central functions fulfilled by mitochondria as both energy generators essential for tissue homeostasis and gateways to programmed apoptotic and necrotic cell death mandate tight control over the quality and quantity of these ubiquitous endosymbiotic organelles. Mitophagy, the targeted engulfment and destruction of mitochondria by the cellular autophagy apparatus, has conventionally been considered as the mechanism primarily responsible for mitochondrial quality control. However, our understanding of how, why, and under what specific conditions mitophagy is activated has grown tremendously over the past decade. Evidence is accumulating that nonmitophagic mitochondrial quality control mechanisms are more important to maintaining normal tissue homeostasis whereas mitophagy is an acute tissue stress response. Moreover, previously unrecognized mitophagic regulation of mitochondrial quantity control, metabolic reprogramming, and cell differentiation suggests that the mechanisms linking genetic or acquired defects in mitophagy to neurodegenerative and cardiovascular diseases or cancer are more complex than simple failure of normal mitochondrial quality control. Here, we provide a comprehensive overview of mitophagy in cellular homeostasis and disease and examine the most revolutionary concepts in these areas. In this context, we discuss evidence that atypical mitophagy and nonmitophagic pathways play central roles in mitochondrial quality control, functioning that was previously considered to be the primary domain of mitophagy. 10.1152/physrev.00005.2018
    Mechanisms of mitophagy in cellular homeostasis, physiology and pathology. Palikaras Konstantinos,Lionaki Eirini,Tavernarakis Nektarios Nature cell biology Mitophagy is an evolutionarily conserved cellular process to remove dysfunctional or superfluous mitochondria, thus fine-tuning mitochondrial number and preserving energy metabolism. In this Review, we survey recent advances towards elucidating the molecular mechanisms that mediate mitochondrial elimination and the signalling pathways that govern mitophagy. We consider the contributions of mitophagy in physiological and pathological contexts and discuss emerging findings, highlighting the potential value of mitophagy modulation in therapeutic intervention. 10.1038/s41556-018-0176-2
    HUWE1 E3 ligase promotes PINK1/PARKIN-independent mitophagy by regulating AMBRA1 activation via IKKα. Di Rita Anthea,Peschiaroli Angelo,D Acunzo Pasquale,Strobbe Daniela,Hu Zehan,Gruber Jens,Nygaard Mads,Lambrughi Matteo,Melino Gerry,Papaleo Elena,Dengjel Jörn,El Alaoui Said,Campanella Michelangelo,Dötsch Volker,Rogov Vladimir V,Strappazzon Flavie,Cecconi Francesco Nature communications The selective removal of undesired or damaged mitochondria by autophagy, known as mitophagy, is crucial for cellular homoeostasis, and prevents tumour diffusion, neurodegeneration and ageing. The pro-autophagic molecule AMBRA1 (autophagy/beclin-1 regulator-1) has been defined as a novel regulator of mitophagy in both PINK1/PARKIN-dependent and -independent systems. Here, we identified the E3 ubiquitin ligase HUWE1 as a key inducing factor in AMBRA1-mediated mitophagy, a process that takes place independently of the main mitophagy receptors. Furthermore, we show that mitophagy function of AMBRA1 is post-translationally controlled, upon HUWE1 activity, by a positive phosphorylation on its serine 1014. This modification is mediated by the IKKα kinase and induces structural changes in AMBRA1, thus promoting its interaction with LC3/GABARAP (mATG8) proteins and its mitophagic activity. Altogether, these results demonstrate that AMBRA1 regulates mitophagy through a novel pathway, in which HUWE1 and IKKα are key factors, shedding new lights on the regulation of mitochondrial quality control and homoeostasis in mammalian cells. 10.1038/s41467-018-05722-3
    RIPK1-mediated induction of mitophagy compromises the viability of extracellular-matrix-detached cells. Hawk Mark A,Gorsuch Cassandra L,Fagan Patrick,Lee Chan,Kim Sung Eun,Hamann Jens C,Mason Joshua A,Weigel Kelsey J,Tsegaye Matyas Abel,Shen Luqun,Shuff Sydney,Zuo Junjun,Hu Stephan,Jiang Lei,Chapman Sarah,Leevy W Matthew,DeBerardinis Ralph J,Overholtzer Michael,Schafer Zachary T Nature cell biology For cancer cells to survive during extracellular matrix (ECM) detachment, they must inhibit anoikis and rectify metabolic deficiencies that cause non-apoptotic cell death. Previous studies in ECM-detached cells have linked non-apoptotic cell death to reactive oxygen species (ROS) generation, although the mechanistic underpinnings of this link remain poorly defined. Here, we uncover a role for receptor-interacting protein kinase 1 (RIPK1) in the modulation of ROS and cell viability during ECM detachment. We find that RIPK1 activation during ECM detachment results in mitophagy induction through a mechanism dependent on the mitochondrial phosphatase PGAM5. As a consequence of mitophagy, ECM-detached cells experience diminished NADPH production in the mitochondria, and the subsequent elevation in ROS levels leads to non-apoptotic death. Furthermore, we find that antagonizing RIPK1/PGAM5 enhances tumour formation in vivo. Thus, RIPK1-mediated induction of mitophagy may be an efficacious target for therapeutics aimed at eliminating ECM-detached cancer cells. 10.1038/s41556-018-0034-2
    Mitophagy inhibits amyloid-β and tau pathology and reverses cognitive deficits in models of Alzheimer's disease. Nature neuroscience Accumulation of damaged mitochondria is a hallmark of aging and age-related neurodegeneration, including Alzheimer's disease (AD). The molecular mechanisms of impaired mitochondrial homeostasis in AD are being investigated. Here we provide evidence that mitophagy is impaired in the hippocampus of AD patients, in induced pluripotent stem cell-derived human AD neurons, and in animal AD models. In both amyloid-β (Aβ) and tau Caenorhabditis elegans models of AD, mitophagy stimulation (through NAD supplementation, urolithin A, and actinonin) reverses memory impairment through PINK-1 (PTEN-induced kinase-1)-, PDR-1 (Parkinson's disease-related-1; parkin)-, or DCT-1 (DAF-16/FOXO-controlled germline-tumor affecting-1)-dependent pathways. Mitophagy diminishes insoluble Aβ and Aβ and prevents cognitive impairment in an APP/PS1 mouse model through microglial phagocytosis of extracellular Aβ plaques and suppression of neuroinflammation. Mitophagy enhancement abolishes AD-related tau hyperphosphorylation in human neuronal cells and reverses memory impairment in transgenic tau nematodes and mice. Our findings suggest that impaired removal of defective mitochondria is a pivotal event in AD pathogenesis and that mitophagy represents a potential therapeutic intervention. 10.1038/s41593-018-0332-9
    Mitophagy and Alzheimer's Disease: Cellular and Molecular Mechanisms. Kerr Jesse S,Adriaanse Bryan A,Greig Nigel H,Mattson Mark P,Cader M Zameel,Bohr Vilhelm A,Fang Evandro F Trends in neurosciences Neurons affected in Alzheimer's disease (AD) experience mitochondrial dysfunction and a bioenergetic deficit that occurs early and promotes the disease-defining amyloid beta peptide (Aβ) and Tau pathologies. Emerging findings suggest that the autophagy/lysosome pathway that removes damaged mitochondria (mitophagy) is also compromised in AD, resulting in the accumulation of dysfunctional mitochondria. Results in animal and cellular models of AD and in patients with sporadic late-onset AD suggest that impaired mitophagy contributes to synaptic dysfunction and cognitive deficits by triggering Aβ and Tau accumulation through increases in oxidative damage and cellular energy deficits; these, in turn, impair mitophagy. Interventions that bolster mitochondrial health and/or stimulate mitophagy may therefore forestall the neurodegenerative process in AD. 10.1016/j.tins.2017.01.002
    Building and decoding ubiquitin chains for mitophagy. Harper J Wade,Ordureau Alban,Heo Jin-Mi Nature reviews. Molecular cell biology Mitochondria produce energy in the form of ATP via oxidative phosphorylation. As defects in oxidative phosphorylation can generate harmful reactive oxygen species, it is important that damaged mitochondria are efficiently removed via a selective form of autophagy known as mitophagy. Owing to a combination of cell biological, structural and proteomic approaches, we are beginning to understand the mechanisms by which ubiquitin-dependent signals mark damaged mitochondria for mitophagy. This Review discusses the biochemical steps and regulatory mechanisms that promote the conjugation of ubiquitin to damaged mitochondria via the PTEN-induced putative kinase 1 (PINK1) and the E3 ubiquitin-protein ligase parkin and how ubiquitin chains promote autophagosomal capture. Recently discovered roles for parkin and PINK1 in the suppression of mitochondrial antigen presentation provide alternative models for how this pathway promotes the survival of neurons. A deeper understanding of these processes has major implications for neurodegenerative diseases, including Parkinson disease, where defects in mitophagy and other forms of selective autophagy are prominent. 10.1038/nrm.2017.129
    Mitochondrial dynamics: regulatory mechanisms and emerging role in renal pathophysiology. Zhan Ming,Brooks Craig,Liu Fuyou,Sun Lin,Dong Zheng Kidney international Mitochondria are a class of dynamic organelles that constantly undergo fission and fusion. Mitochondrial dynamics is governed by a complex molecular machinery and finely tuned by regulatory proteins. During cell injury or stress, the dynamics is shifted to fission, resulting in mitochondrial fragmentation, which contributes to mitochondrial damage and consequent cell injury and death. Emerging evidence has suggested a role of mitochondrial fragmentation in the pathogenesis of renal diseases including acute kidney injury and diabetic nephropathy. A better understanding of the regulation of mitochondrial dynamics and its pathogenic changes may unveil novel therapeutic strategies. 10.1038/ki.2012.441
    Renal protective effects of resveratrol. Kitada Munehiro,Koya Daisuke Oxidative medicine and cellular longevity Resveratrol (3,5,4'-trihydroxystilbene), a natural polyphenolic compound found in grapes and red wine, is reported to have beneficial effects on cardiovascular diseases, including renal diseases. These beneficial effects are thought to be due to this compound's antioxidative properties: resveratrol is known to be a robust scavenger of reactive oxygen species (ROS). In addition to scavenging ROS, resveratrol may have numerous protective effects against age-related disorders, including renal diseases, through the activation of SIRT1. SIRT1, an NAD(+)-dependent deacetylase, was identified as one of the molecules through which calorie restriction extends the lifespan or delays age-related diseases, and this protein may regulate multiple cellular functions, including apoptosis, mitochondrial biogenesis, inflammation, glucose/lipid metabolism, autophagy, and adaptations to cellular stress, through the deacetylation of target proteins. Previous reports have shown that resveratrol can ameliorate several types of renal injury, such as diabetic nephropathy, drug-induced injury, aldosterone-induced injury, ischemia-reperfusion injury, sepsis-related injury, and unilateral ureteral obstruction, in animal models through its antioxidant effect or SIRT1 activation. Therefore, resveratrol may be a useful supplemental treatment for preventing renal injury. 10.1155/2013/568093
    In vivo RNA interference models of inducible and reversible Sirt1 knockdown in kidney cells. Chuang Peter Y,Xu Jin,Dai Yan,Jia Fu,Mallipattu Sandeep K,Yacoub Rabi,Gu Leyi,Premsrirut Prem K,He John C The American journal of pathology The silent mating type information regulation 2 homolog 1 gene (Sirt1) encodes an NAD-dependent deacetylase that modifies the activity of well-known transcriptional regulators affected in kidney diseases. Sirt1 is expressed in the kidney podocyte, but its function in the podocyte is not clear. Genetically engineered mice with inducible and reversible Sirt1 knockdown in widespread, podocyte-specific, or tubular-specific patterns were generated. We found that mice with 80% knockdown of renal Sirt1 expression have normal glomerular function under the basal condition. When challenged with doxorubicin (Adriamycin), these mice develop marked albuminuria, glomerulosclerosis, mitochondrial injury, and impaired autophagy of damaged mitochondria. Reversal of Sirt1 knockdown during the early phase of Adriamycin-induced nephropathy prevented the progression of glomerular injury and reduced the accumulation of dysmorphic mitochondria in podocytes but did not reverse the progression of albuminuria and glomerulosclerosis. Sirt1 knockdown mice with diabetes mellitus, which is known to cause mitochondrial dysfunction in the kidney, developed more albuminuria and mitochondrial dysfunction compared with diabetic mice without Sirt1 knockdown. In conclusion, these results demonstrate that our RNA interference-mediated Sirt1 knockdown models are valid and versatile tools for characterizing the function of Sirt1 in the kidney; Sirt1 plays a role in homeostatic maintenance of podocytes under the condition of mitochondrial stress/injury. 10.1016/j.ajpath.2014.03.016
    Peroxisomes and Kidney Injury. Vasko Radovan Antioxidants & redox signaling SIGNIFICANCE:Peroxisomes are organelles present in most eukaryotic cells. The organs with the highest density of peroxisomes are the liver and kidneys. Peroxisomes possess more than fifty enzymes and fulfill a multitude of biological tasks. They actively participate in apoptosis, innate immunity, and inflammation. In recent years, a considerable amount of evidence has been collected to support the involvement of peroxisomes in the pathogenesis of kidney injury. RECENT ADVANCES:The nature of the two most important peroxisomal tasks, beta-oxidation of fatty acids and hydrogen peroxide turnover, functionally relates peroxisomes to mitochondria. Further support for their communication and cooperation is furnished by the evidence that both organelles share the components of their division machinery. Until recently, the majority of studies on the molecular mechanisms of kidney injury focused primarily on mitochondria and neglected peroxisomes. CRITICAL ISSUES:The aim of this concise review is to introduce the reader to the field of peroxisome biology and to provide an overview of the evidence about the contribution of peroxisomes to the development and progression of kidney injury. The topics of renal ischemia-reperfusion injury, endotoxin-induced kidney injury, diabetic nephropathy, and tubulointerstitial fibrosis, as well as the potential therapeutic implications of peroxisome activation, are addressed in this review. FUTURE DIRECTIONS:Despite recent progress, further studies are needed to elucidate the molecular mechanisms induced by dysfunctional peroxisomes and the role of the dysregulated mitochondria-peroxisome axis in the pathogenesis of renal injury. Antioxid. Redox Signal. 25, 217-231. 10.1089/ars.2016.6666
    High glucose induces apoptosis via upregulation of Bim expression in proximal tubule epithelial cells. Zhang Xiao-Qian,Dong Jian-Jun,Cai Tian,Shen Xue,Zhou Xiao-Jun,Liao Lin Oncotarget Diabetic nephropathy is the primary cause of end-stage renal disease. Apoptosis of tubule epithelial cells is a major feature of diabetic nephropathy. The mechanisms of high glucose (HG) induced apoptosis are not fully understood. Here we demonstrated that, HG induced apoptosis via upregulating the expression of proapoptotic Bcl-2 homology domain 3 (BH3)-only protein Bim protein, but not bring a significant change in the baseline level of autophagy in HK2 cells. The increase of Bim expression was caused by the ugregulation of transcription factors, FOXO1 and FOXO3a. Bim expression initiates BAX/BAK-mediated mitochondria-dependent apoptosis. Silence of Bim by siRNA in HK2 cells prevented HG-induced apoptosis and also sensitized HK2 cells to autophagy during HG treatment. The autophagy inhibitor 3-MA increased the injury in Bim knockdown HK2 cells by retriggering apoptosis. The above results suggest a Bim-independent apoptosis pathway in HK2 cells, which normally could be inhibited by autophagy. Overall, our results indicate that HG induces apoptosis via up-regulation of Bim expression in proximal tubule epithelial cells. 10.18632/oncotarget.15491
    Emerging role of Unfolded Protein Response (UPR) mediated proteotoxic apoptosis in diabetes. Pandey Vivek Kumar,Mathur Alpana,Kakkar Poonam Life sciences Endoplasmic reticulum (ER) is a crucial single membrane organelle that acts as a quality control system for cellular proteins as it is intricately involved in their synthesis, folding and trafficking to the respective targets. Type 2 diabetes is characterized by enhanced blood glucose level that promotes insulin resistance and hampers cellular glucose metabolism. Hyperglycemia provokes mitochondrial ROS production and glycation of proteins which exert a tremendous load on ER for conventional refolding of misfolded/unfolded and nascent proteins that perturb ER homeostasis resulting in apoptotic cell death. Impairment in ER functions is suspected to be through specific ER membrane-bound proteins known as Unfolded Protein Response (UPR) sensor proteins. Conformational changes in these proteins induce oligomerization and cross-autophosphorylation which facilitate processes required for the restoration of ER homeostatic imbalance. Multiple studies have reported the involvement of UPR mediated autophagy and apoptotic pathways in the progression of metabolic disorders including diabetes, cardiac ischemia/reperfusion injury and hypoxia-mediated cell death. In this review, the involvement of UPR pathways in the progression of diabetes associated complications have been addressed, which underscores molecular crosstalks during neuropathy, nephropathy, hepatic injury and retinopathy. A better understanding of these molecular interventions may reveal advanced therapeutic approaches for preventing diabetic comorbidities. The article also highlights the importance of phytochemicals that are emerging as novel ER stress inhibitors and are being explored for targeted interaction in preventing cell death responses during diabetes. 10.1016/j.lfs.2018.11.041
    Disturbance of mitochondrial dynamics and mitophagy in sepsis-induced acute kidney injury. Liu Jian-Xing,Yang Chen,Zhang Wei-Huang,Su Hong-Yong,Liu Ze-Jian,Pan Qingjun,Liu Hua-Feng Life sciences AIMS:The renal tubule cells require a large number of mitochondria to supply ATP due to their high-energy demand during reabsorption and secretion against chemical gradients and result in mitochondria susceptible to disorder and injury during stress conditions. Injured mitochondria are eventually degraded by mitophagy, and disturbances in mitophagy are associated with the pathogenesis of acute kidney injury (AKI) such as diabetic nephropathy and glomerulosclerosis. However, whether a disturbance in mitophagy has occurred and the role it plays in (SAKI) is still unclear. Therefore, the aim of this study was to investigate the key features of mitophagy and mitochondrial dynamics in sepsis-induced acute kidney injury (SAKI). MAIN METHODS:In this study, a murine septic AKI model induced by cecal ligation and puncture (CLP) was built; mitophagy and mitochondrial dynamics were measured in mice kidney in different time point. KEY FINDINGS:The results showed that mitochondrial dynamics were characterized by fission/fusion aberrant, however more inclined to fission, and mitochondrial associated apoptosis was elevated over-time during SAKI. Furthermore, mitophagy was impaired in the later phase of SAKI, although elevated in early stage of SAKI. The results indicate that the underlying mechanisms of impaired mitophagy may associate with the cleavage of Parkin via caspases activated by NLRP3, at least partly. SIGNIFICANCE:It is conceivable that this selective autophagic process and quality control machinery was impaired, leading to the accumulation of damaged mitochondria, oxidative stress, and cell death. Therefore, a targeted approach, by enhancing mitophagy during SAKI, may be a promising therapeutic strategy. 10.1016/j.lfs.2019.116828
    Dietary restriction regimens for fighting kidney disease: Insights from rodent studies. Singh Gaaminepreet,Krishan Pawan Experimental gerontology This review critically discusses the research findings on the effects of various dietary restriction regimens in rodent models of kidney disease. Long-term caloric restriction executed at both early and progressive stages of kidney disease was found to exert beneficial effects in rodents. Moreover, some studies have also demonstrated the efficacy of short-term caloric restriction in treating the kidney disease of variable aetiologies possibly by improving mitochondrial dysfunction, autophagy process and suppression of inflammation. However, the mechanisms underlying these short-term caloric restriction mediated protective effects in rodent models of kidney disease are not completely understood. Importantly, few available evidences have also suggested that carbohydrate restriction can exert beneficial effects in aging and experimentally induced renal injury models, but the mechanisms are not explored yet. Interestingly, the benefits of low protein diet in kidney disease models are extensively reported in literature. However, in most of these studies implementation of the low protein dietary regimen was found to associated with increased high carbohydrate and caloric intake (non-isocaloric). Thus, testing the effects of low protein diet under isocaloric conditions might further help to particularly understand the role of dietary protein content in pathology of kidney disease. Moreover, the direct evidences comparing the efficacy of various dietary restriction regimens in rodent models of kidney diseases are also scarce at present. 10.1016/j.exger.2019.110738
    Orientin Protects Podocytes from High Glucose Induced Apoptosis through Mitophagy. Kong Zi-Li,Che Kui,Hu Jian-Xia,Chen Ying,Wang Yun-Yang,Wang Xiang,Lü Wen-Shan,Wang Yan-Gang,Chi Jing-Wei Chemistry & biodiversity Diabetic nephropathy (DN) is one of the serious complications of diabetes mellitus. Orientin, a major bioactive constituent of Fenugreek, has been reported to possess antihyperglycemic properties. However, its effects on DN remain unclear. Therefore, we explored the protective effect of orientin on podocytes. Here, we assessed cell viability and toxicity, level of autophagy, mitochondrial morphological changes, and podocyte apoptosis. The results indicated that high glucose (HG) induced podocyte apoptosis as well as mitochondrial injury can be partially blocked by orientin. The results showed that orientin could repair autophagy disorder induced by HG, while 3-methyladenine (3-MA) reversed the protection of orientin. Our study demonstrated the possibility of treating DN with orientin. 10.1002/cbdv.201900647
    Renal effects of SGLT2 inhibitors: an update. Nespoux Josselin,Vallon Volker Current opinion in nephrology and hypertension PURPOSE OF REVIEW:SGLT2 inhibitors are a new class of antihyperglycemic drugs that protect kidneys and hearts of type 2 diabetic (T2DM) patients with preserved kidney function from failing. Here we discuss new insights on renal protection. RECENT FINDINGS:Also in T2DM patients with CKD, SGLT2 inhibition causes an immediate functional reduction in glomerular filtration rate (GFR) and reduces blood pressure and preserves kidney and heart function in the long-term, despite a lesser antihyperglycemic effect. According to modeling studies, the GFR reduction reduces the tubular transport work and metabolic demand, thereby improving renal cortical oxygenation. In humans, the latter is linked to protection from CKD. Urine metabolomics in T2DM patients suggested improved renal mitochondrial function in response to SGLT2 inhibition, and experimental studies indicated improved tubular autophagy. Modeling studies predicted that also in diabetic CKD, SGLT2 inhibition is natriuretic and potentially stimulates erythropoiesis by mimicking systemic hypoxia in the kidney. Meta-analyses indicated that SGLT2 inhibition also reduces risk and severity of acute kidney injury in T2DM patients. Studies in nondiabetic mice implied inhibition of the renal urate transporter URAT1 in the uricosuric effect of SGLT2 inhibition. SUMMARY:Renoprotection of SGLT2 inhibition involves blood glucose-dependent and independent effects and extends to CKD. 10.1097/MNH.0000000000000584
    Dyslipidemia in Kidney Disorders: Perspectives on Mitochondria Homeostasis and Therapeutic Opportunities. Lin Pei-Hui,Duann Pu Frontiers in physiology To excrete body nitrogen waste and regulate electrolyte and fluid balance, the kidney has developed into an energy factory with only second to the heart in mitochondrial content in the body to meet the high-energy demand and regulate homeostasis. Energy supply from the renal mitochondria majorly depends on lipid metabolism, with programed enzyme systems in fatty acid β-oxidation and Krebs cycle. Renal mitochondria integrate several metabolic pathways, including AMPK/PGC-1α, PPARs, and CD36 signaling to maintain energy homeostasis for dynamic and static requirements. The pathobiology of several kidney disorders, including diabetic nephropathy, acute and chronic kidney injuries, has been primarily linked to impaired mitochondrial bioenergetics. Such homeostatic disruption in turn stimulates a pathological adaptation, with mitochondrial enzyme system reprograming possibly leading to dyslipidemia. However, this alteration, while rescuing oncotic pressure deficit secondary to albuminuria and dissipating edematous disorder, also imposes an ominous lipotoxic consequence. Reprograming of lipid metabolism in kidney injury is essential to preserve the integrity of kidney mitochondria, thereby preventing massive collateral damage including excessive autophagy and chronic inflammation. Here, we review dyslipidemia in kidney disorders and the most recent advances on targeting mitochondrial energy metabolism as a therapeutic strategy to restrict renal lipotoxicity, achieve salutary anti-edematous effects, and restore mitochondrial homeostasis. 10.3389/fphys.2020.01050
    The effect of energy restriction on development and progression of chronic kidney disease: review of the current evidence. Afsar Baris,Afsar Rengin Elsurer,Copur Sidar,Sag Alan A,Ortiz Alberto,Kanbay Mehmet The British journal of nutrition Energy restriction (ER) has anti-ageing effects and probably protects from a range of chronic diseases including cancer, diabetes and chronic kidney disease (CKD). Specifically, ER has a positive impact on experimental kidney ageing, CKD (diabetic nephropathy, polycystic kidney disease) and acute kidney injury (nephrotoxic, ischaemia-reperfusion injury) through such mechanisms as increased autophagy, mitochondrial biogenesis and DNA repair, and decreased inflammation and oxidative stress. Key molecules contributing to ER-mediated kidney protection include adenosine monophosphate-activated protein kinase, sirtuin-1 and PPAR-γ coactivator 1α. However, CKD is a complex condition, and ER may potentially worsen CKD complications such as protein-energy wasting, bone-mineral disorders and impaired wound healing. ER mimetics are drugs, such as metformin and Na-glucose co-transporter-2 which mimic the action of ER. This review aims to provide comprehensive data regarding the effect of ER on CKD progression and outcomes. 10.1017/S000711452000358X
    Molecular Mechanistic Pathways Targeted by Natural Antioxidants in the Prevention and Treatment of Chronic Kidney Disease. Mohany Mohamed,Ahmed Mohammed M,Al-Rejaie Salim S Antioxidants (Basel, Switzerland) Chronic kidney disease (CKD) is the progressive loss of renal function and the leading cause of end-stage renal disease (ESRD). Despite optimal therapy, many patients progress to ESRD and require dialysis or transplantation. The pathogenesis of CKD involves inflammation, kidney fibrosis, and blunted renal cellular antioxidant capacity. In this review, we have focused on in vitro and in vivo experimental and clinical studies undertaken to investigate the mechanistic pathways by which these compounds exert their effects against the progression of CKD, particularly diabetic nephropathy and kidney fibrosis. The accumulated and collected data from preclinical and clinical studies revealed that these plants/bioactive compounds could activate autophagy, increase mitochondrial bioenergetics and prevent mitochondrial dysfunction, act as modulators of signaling pathways involved in inflammation, oxidative stress, and renal fibrosis. The main pathways targeted by these compounds include the canonical nuclear factor kappa B (NF-κB), canonical transforming growth factor-beta (TGF-β), autophagy, and Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid factor 2-related factor 2 (Nrf2)/antioxidant response element (ARE). This review presented an updated overview of the potential benefits of these antioxidants and new strategies to treat or reduce CKD progression, although the limitations related to the traditional formulation, lack of standardization, side effects, and safety. 10.3390/antiox11010015
    Interplay of oxidative, nitrosative/nitrative stress, inflammation, cell death and autophagy in diabetic cardiomyopathy. Varga Zoltán V,Giricz Zoltán,Liaudet Lucas,Haskó György,Ferdinandy Peter,Pacher Pál Biochimica et biophysica acta Diabetes is a recognized risk factor for cardiovascular diseases and heart failure. Diabetic cardiovascular dysfunction also underscores the development of diabetic retinopathy, nephropathy and neuropathy. Despite the broad availability of antidiabetic therapy, glycemic control still remains a major challenge in the management of diabetic patients. Hyperglycemia triggers formation of advanced glycosylation end products (AGEs), activates protein kinase C, enhances polyol pathway, glucose autoxidation, which coupled with elevated levels of free fatty acids, and leptin have been implicated in increased generation of superoxide anion by mitochondria, NADPH oxidases and xanthine oxidoreductase in diabetic vasculature and myocardium. Superoxide anion interacts with nitric oxide forming the potent toxin peroxynitrite via diffusion limited reaction, which in concert with other oxidants triggers activation of stress kinases, endoplasmic reticulum stress, mitochondrial and poly(ADP-ribose) polymerase 1-dependent cell death, dysregulates autophagy/mitophagy, inactivates key proteins involved in myocardial calcium handling/contractility and antioxidant defense, activates matrix metalloproteinases and redox-dependent pro-inflammatory transcription factors (e.g. nuclear factor kappaB) promoting inflammation, AGEs formation, eventually culminating in myocardial dysfunction, remodeling and heart failure. Understanding the complex interplay of oxidative/nitrosative stress with pro-inflammatory, metabolic and cell death pathways is critical to devise novel targeted therapies for diabetic cardiomyopathy, which will be overviewed in this brief synopsis. This article is part of a Special Issue entitled: Autophagy and protein quality control in cardiometabolic diseases. 10.1016/j.bbadis.2014.06.030
    The Emerging Role of Sirtuin 1 in Cellular Metabolism, Diabetes Mellitus, Diabetic Kidney Disease and Hypertension. Guclu A,Erdur F M,Turkmen K Experimental and clinical endocrinology & diabetes : official journal, German Society of Endocrinology [and] German Diabetes Association Despite diagnostic and therapeutic approaches, diabetic kidney disease (DKD) is the most common cause of end-stage renal disease worldwide. Sirtuins, a group of nicotinamid adenine dinucleotide (NAD) dependent enzymes, can deacetylase target enzymes that regulate a wide variety of cellular processes regarding protein, carbohydrate and lipid metabolism, mitochondrial homeostasis and programmed cell death mechanisms including autophagy and apoptosis. Among sirtuins, sirtuin 1 (SIRT1) has been the most studied one in the pathogenesis and progression of DKD. In recent years, the relation between SIRT1 and hypertension was also evaluated.In the present review, we aimed to represent the mechanisms of SIRT1 in glucose and lipid metabolism and in the pathogenesis of diabetes mellitus. We also sought to highlight the emerging role of SIRT1 in the pathogenesis and treatment of DKD and hypertension. 10.1055/s-0035-1565067
    Autophagy Protects against Palmitic Acid-Induced Apoptosis in Podocytes in vitro. Jiang Xu-Shun,Chen Xue-Mei,Wan Jiang-Min,Gui Hai-Bo,Ruan Xiong-Zhong,Du Xiao-Gang Scientific reports Autophagy is a highly conserved degradation process that is involved in the clearance of proteins and damaged organelles to maintain intracellular homeostasis and cell integrity. Type 2 diabetes is often accompanied by dyslipidemia with elevated levels of free fatty acids (FFAs). Podocytes, as an important component of the filtration barrier, are susceptible to lipid disorders. The loss of podocytes causes proteinuria, which is involved in the pathogenesis of diabetic nephropathy. In the present study, we demonstrated that palmitic acid (PA) promoted autophagy in podocytes. We further found that PA increased the production of reactive oxygen species (ROS) in podocytes and that NAC (N-acetyl-cysteine), a potent antioxidant, significantly eliminated the excessive ROS and suppressed autophagy, indicating that the increased generation of ROS was associated with the palmitic acid-induced autophagy in podocytes. Moreover, we also found that PA stimulation decreased the mitochondrial membrane potential in podocytes and induced podocyte apoptosis, while the inhibition of autophagy by chloroquine (CQ) enhanced palmitic acid-induced apoptosis accompanied by increased ROS generation, and the stimulation of autophagy by rapamycin (Rap) remarkably suppressed palmitic acid-induced ROS generation and apoptosis. Taken together, these in vitro findings suggest that PA-induced autophagy in podocytes is mediated by ROS production and that autophagy plays a protective role against PA-induced podocyte apoptosis. 10.1038/srep42764
    PGC1 Activators Mitigate Diabetic Tubulopathy by Improving Mitochondrial Dynamics and Quality Control. Lee So-Young,Kang Jun Mo,Kim Dong-Jin,Park Seon Hwa,Jeong Hye Yun,Lee Yu Ho,Kim Yang Gyun,Yang Dong Ho,Lee Sang Ho Journal of diabetes research In this study, we investigated the effect of PGC1 activators on mitochondrial fusion, fission, and autophagic quality control in renal tubular cells in a diabetic environment in vivo and in vitro. We also examined whether the upregulation of PGC1 attenuates diabetic tubulopathy by normalizing mitochondrial homeostasis. . HKC8 cells were subjected to high-glucose conditions (30 mM D-glucose). Diabetes was induced with streptozotocin (STZ, 50 mg/kg i.p. for 5 days) in male C57/BL6J mice. AICAR or metformin was used as a PGC1 activator. Treatment with the PGC1 activators AICAR and metformin improved functional mitochondrial mass in HKC8 cells in high-glucose conditions. Moreover, in renal proximal tubular cells, increased PGC1 activity correlated with the reversal of changes in Drp1, Mfn1, and LC3-II protein expression in a high-glucose environment. Normalized mitochondrial life cycles resulted in low ROS production and reduced apoptosis. AICAR and metformin treatment effectively mitigated albuminuria and renal histopathology and decreased the expression of TGF1 and SMA in the kidneys of diabetic mice. . Our results demonstrate that increases in PGC1 activity improve diabetic tubulopathy by modulating mitochondrial dynamics and autophagy. 10.1155/2017/6483572
    Autophagy and kidney inflammation. Kimura Tomonori,Isaka Yoshitaka,Yoshimori Tamotsu Autophagy Inflammation plays a pivotal role in pathophysiological processes of kidney diseases. Macroautophagy/autophagy plays multiple roles in inflammatory responses, and the regulation of inflammation by autophagy has great potential as a treatment for damaged kidneys. A growing body of evidence suggests autophagy protects kidney from versatile kidney inflammatory insults, including those that are acute, chronic, metabolic, and aging-related. It is noteworthy that, in kidney, mitophagy is active, and damaged lysosomes are removed by autophagy. In this mode, autophagy suppresses inflammation to protect the kidney. Systemic inflammation also affects the kidney via pro-inflammatory cytokines and infiltration of inflammatory cells, and autophagy also has a regulatory role in systemic inflammation. This review focuses on the roles of autophagy in kidney diseases and aging through inflammation, and discusses the potential usage of autophagy as an inflammatory modulator for the treatment of kidney diseases. 10.1080/15548627.2017.1309485
    Autophagy in Chronic Kidney Diseases. Lin Tien-An,Wu Victor Chien-Chia,Wang Chao-Yung Cells Autophagy is a cellular recycling process involving self-degradation and reconstruction of damaged organelles and proteins. Current evidence suggests that autophagy is critical in kidney physiology and homeostasis. In clinical studies, autophagy activations and inhibitions are linked to acute kidney injuries, chronic kidney diseases, diabetic nephropathies, and polycystic kidney diseases. Oxidative stress, inflammation, and mitochondrial dysfunction, which are implicated as important mechanisms underlying many kidney diseases, modulate the autophagy activation and inhibition and lead to cellular recycling dysfunction. Abnormal autophagy function can induce loss of podocytes, damage proximal tubular cells, and glomerulosclerosis. After acute kidney injuries, activated autophagy protects tubular cells from apoptosis and enhances cellular regeneration. Patients with chronic kidney diseases have impaired autophagy that cannot be reversed by hemodialysis. Multiple nephrotoxic medications also alter the autophagy signaling, by which the mechanistic insights of the drugs are revealed, thus providing the unique opportunity to manage the nephrotoxicity of these drugs. In this review, we summarize the current concepts of autophagy and its molecular aspects in different kidney cells pathophysiology. We also discuss the current evidence of autophagy in acute kidney injury, chronic kidney disease, toxic effects of drugs, and aging kidneys. In addition, we examine therapeutic possibilities targeting the autophagy system in kidney diseases. 10.3390/cells8010061
    Ferulic Acid Protects Hyperglycemia-Induced Kidney Damage by Regulating Oxidative Insult, Inflammation and Autophagy. Chowdhury Sayantani,Ghosh Sumit,Das Abhishek Kumar,Sil Parames C Frontiers in pharmacology Oxidative insult, inflammation, apoptosis and autophagy play a pivotal role in the etiology of diabetic nephropathy, a global health concern. Ferulic acid, a phytochemical, is reported to protect against varied diseased conditions. However, the ameliorative role and mechanisms of ferulic acid in averting STZ-mediated nephrotoxicity largely remains unknown. For study, a single intraperitoneal injection of streptozotocin (50 mg kg body wt.) was administered in experimental rats to induce diabetes. The diabetic rats exhibited a rise in blood glucose level as well as kidney to body weight ratio, a decrease in serum insulin level, severe kidney tissue damage and dysfunction. Elevation of intracellular ROS level, altered mitochondrial membrane potential and cellular redox balance impairment shown the participation of oxidative stress in hyperglycemia-triggered renal injury. Treatment with ferulic acid (50 mg kg body wt., orally for 8 weeks), post-diabetic induction, could markedly ameliorate kidney injury, renal cell apoptosis, inflammation and defective autophagy in the kidneys. The underlying mechanism for such protection involved the modulation of AGEs, MAPKs (p38, JNK, and ERK 1/2), NF-κB mediated inflammatory pathways, mitochondria-dependent and -independent apoptosis as well as autophagy induction. In cultured NRK-52E cells, ferulic acid (at an optimum dose of 75 μM) could counter excessive ROS generation, induce autophagy and inhibit apoptotic death of cells under high glucose environment. Blockade of autophagy could significantly eradicate the protective effect of ferulic acid in high glucose-mediated cell death. Together, the study confirmed that ferulic acid, exhibiting hypoglycemic, antioxidant, anti-inflammatory, anti-apoptotic activities and role in autophagy, could circumvent oxidative stress-mediated renal cell damage. 10.3389/fphar.2019.00027
    QiDiTangShen Granules Activate Renal Nutrient-Sensing Associated Autophagy in db/db Mice. Wang Xiangming,Zhao Li,Ajay Amrendra K,Jiao Baihai,Zhang Xianhui,Wang Chunguo,Gao Xue,Yuan Zhongyu,Liu Hongfang,Liu Wei Jing Frontiers in physiology QiDiTangShen granules (QDTS) have been proven to reduce the proteinuria in patients with diabetic nephropathy (DN) effectively. The present study was aimed to investigate the mechanism underlying QDTS's renoprotection. The main components of QDTS were identified by ultra-high liquid chromatography-tandem mass spectrometry and pharmacological databases, among which active components were screened by oral bioavailability and drug-likeness. Their regulation on autophagy-related nutrient-sensing signal molecules (AMPK, SIRT1, and mTOR) was retrieved and analyzed through the Pubmed database. Then, db/db mice were randomly divided into three groups (model control, valsartan and QDTS), and given intragastric administration for 12 weeks, separately. Fasting and random blood glucose, body weight, urinary albumin excretion (UAE) and injury markers of liver and kidney were investigated to evaluate the effects and safety. Renal histological lesions were assessed, and the expressions of proteins related to nutrient-sensing signals and autophagy were investigated. Thirteen active components were screened from 78 components identified. Over half the components had already been reported to improve nutrient-sensing signals. QDTS significantly reduced UAE, ameliorated mesangial matrix deposition, alleviate the expression of protein and mRNA of TGF-β, α-SMA, and Col I, as well as improved the quality of mitochondria and the number of autophagic vesicles of renal tubular cells although the blood glucose was not decreased in db/db mice. Compared to the db/db group, the expression of the autophagy-inducible protein (Atg14 and Beclin1) and microtubule-associated protein 1 light chain 3-II (LC3-II) were up-regulated, autophagic substrate transporter p62 was down-regulated in QDTS group. It was also found that the expression of SIRT1 and the proportion of p-AMPK (thr172)/AMPK were increased, while the p-mTOR (ser2448)/mTOR ratio was decreased after QDTS treatment in db/db mice, which was consistent with the effect of its active ingredients on the nutrient-sensing signal pathway as reported previously. Therefore, QDTS may prevent the progression of DN by offering the anti-fibrotic effect. The renoprotection is probably attributable to the regulation of nutrient-sensing signal pathways, which activates autophagy. 10.3389/fphys.2019.01224
    Sirt3 overexpression alleviates hyperglycemia-induced vascular inflammation through regulating redox balance, cell survival, and AMPK-mediated mitochondrial homeostasis. Wang Yunfei,Zhang Xue,Wang Peng,Shen Yiting,Yuan Kai,Li Maoran,Liang Wei,Que Huafa Journal of receptor and signal transduction research Sirtuin-3 (Sirt3), a NAD-dependent deacetylase, has been reported to be involved in many biological processes. The present study aimed to investigate the effect and mechanism of Sirt3 on diabetic mice and human umbilical vein endothelial cells (HUVECs) under high glucose (HG) condition. HUVECs were cultured under HG and inflammation pathway was determined via qPCR, western blots, and immunofluorescence. Sirt3 expression was reduced in the progression of diabetic nephropathy. Overexpression of Sirt3 sustains renal function and retard the development of diabetic nephropathy. Mechanistically, Sirt3 overexpression attenuated hyperglycemia-mediated endothelial cells apoptosis in kidney. Besides, Sirt3 overexpression repressed oxidative injury and blocked caspase-9-related apoptosis pathway. Moreover, we found that Sirt3 overexpression was associated with AMPK activation and the latter elevates PGC1α-related mitochondrial protective system, especially mitochondrial autophagy. Loss of opa1 and/or inhibition of AMPK could depress mitochondrial autophagy and exacerbates mitochondrial function, finally contributing to the death of human renal mesangial cells. Our results demonstrated the beneficial effects of Sirt3 in the progression of diabetic nephropathy. Increased Sirt3-activated AMPK pathway, augments PGC1α-related mitochondrial protective system, sustained redox balance and closed caspase-9-involved apoptosis pathway in the setting of diabetic nephropathy. 10.1080/10799893.2019.1684521
    Metformin rescues Parkin protein expression and mitophagy in high glucose-challenged human renal epithelial cells by inhibiting NF-κB via PP2A activation. Zhao Yulan,Sun Mingjin Life sciences Our preliminary research revealed that metformin, a classic anti-diabetic drug, could rescue Parkin protein expression and mitophagy in high glucose-challenged human renal epithelial cells in vitro, but the molecular mechanism remains to be explored. In the study, Human Renal Cortical Epithelial Cells (HRCEpiC) and Human Renal Proximal Tubular Epithelial Cells (HRPTEpic) were challenged with high glucose with or without metformin pre-treatment to monitor Parkin mRNA and protein expression level change. PRKN gene knockdown was performed by lentiviral-based shRNA delivery. Cell viability, apoptosis and mitophagy were monitored after treatment. Mitochondrial damage was evaluated by analyzing mitochondrial permeability transition pore opening, membrane potential change, mitochondrial superoxide accumulation and cytochrome C release. Protein levels of activating transcription factor 4 (ATF4), p53 phospho-Ser15, IκBα phosphor-Ser32, IKKα phosphor-Ser176/180 in whole cell lysate and nuclear entry of p50/p65 were assessed by western blot. Okadaic acid was used to inhibit protein phosphatase 2A (PP2A). The data suggested high glucose challenge significantly reduced PRKN gene expression, mitophagy, mitochondria integrity and cell viability in vitro, which was rescued by metformin co-treatment. The effects of metformin were crippled by PRKN gene knockdown. Metformin increased PRKN gene transcription while reducednuclear factor kappa B (NF-κB) activation but not that of p53 or ATF4. Inhibiting PP2A weakened NF-κB inhibition and PRKN induction by metformin in high glucose-challenged cells, reducing its mitochondrial protective and cytoprotective effect. So, we concluded thatmetformin protects human renal epithelial cells from high glucose-induced apoptosis by restoring Parkin protein expression and mitophagy via PP2A activation and NF-κB inhibition. 10.1016/j.lfs.2020.117382
    PINK1/Parkin mediated mitophagy ameliorates palmitic acid-induced apoptosis through reducing mitochondrial ROS production in podocytes. Jiang Xu-Shun,Chen Xue-Mei,Hua Wei,He Jun-Ling,Liu Ting,Li Xun-Jia,Wan Jiang-Min,Gan Hua,Du Xiao-Gang Biochemical and biophysical research communications Diabetic nephropathy (DN), the primary cause of end-stage renal disease (ESRD), is often accompanied by dyslipidemia, which is closely related to the occurrence and development of DN and even the progression to ESRD. Mitophagy, the selective degradation of damaged and dysfunctional mitochondria by autophagy, is a crucial mitochondrial quality control mechanism, and largely regulated by PINK1 (PTEN-induced putative kinase 1)/Parkin signaling pathway. In the present study, we demonstrated that PA induced mitochondrial damage and excessive mitoROS generation in podocytes. We also found PA treatment resulted in the activation of mitophagy by increasing co-localization of GFP-LC3 with mitochondria and enhancing the formation of mitophagosome, stabilization of PINK1 and mitochondrial translocation of Parkin, which indicated that PINK1/Parkin pathway was involved in PA-induced mitophagy in podocytes. Furthermore, inhibition of mitophagy by silencing Parkin dramatically aggravated PA-induced mitochondrial dysfunction, mitoROS production, and further enhanced PA-induced apoptosis of podocytes. Finally, we showed that PINK1/Parkin pathway were up-regulated in kidney of high fat diet (HFD)-induced obese rats. Taken together, our results suggest that PINK1/Parkin mediated mitophagy plays a protective role in PA-induced podocytes apoptosis through reducing mitochondrial ROS production and that enhancing mitophagy provides a potential therapeutic strategy for kidney diseases with hyperlipidemia, such as DN. 10.1016/j.bbrc.2020.02.170
    Research progress of sirtuins in renal and cardiovascular diseases. Wang Wanning,Li Jia,Cai Lu Current opinion in nephrology and hypertension PURPOSE OF REVIEW:Sirtuins are a family of nicotinamide adenine dinucleotide+-dependent enzymes catalyzing target protein deacetylation to modulate cellular metabolism, response to oxidative stress and inflammation, senescence, autophagy and apoptosis. In this review, we provide an overview of recent studies regarding the alterations and roles of sirtuins in a variety of renal and cardiovascular diseases. We are also going to highlight activators and inhibitors of sirtuins in the prevention of these diseases. This will help us to understand how this field may change in the future. RECENT FINDING:Recent studies have elucidated how physical or diseased conditions alter the expressions and enzyme activity of sirtuins and expounded sexual differences in sirtuins functions. In addition, interventions by targeting sirtuins have been applied in preclinical and clinical studies to prevent or slow the development of related diseases. SUMMARY:The advantages of female sex in renal and cardiovascular diseases are partially due to the expression and function of sirtuins. Estrogen activates sirtuins and in turn sirtuins promote estrogen receptor signaling. In addition, the hypoglycemic agents, sodium-glucose cotransporter 2 inhibitors protect against diabetic nephropathy at least in part via activating SIRT-1. Although several compounds targeted sirtuins are promising drug candidates in a variety of renal and cardiovascular diseases, well designed large clinical trials are still required to identify their efficacy and safety. 10.1097/MNH.0000000000000660
    Pathophysiology of diabetic kidney disease: impact of SGLT2 inhibitors. DeFronzo Ralph A,Reeves W Brian,Awad Alaa S Nature reviews. Nephrology Diabetic kidney disease is the leading cause of kidney failure worldwide; in the USA, it accounts for over 50% of individuals entering dialysis or transplant programmes. Unlike other complications of diabetes, the prevalence of diabetic kidney disease has failed to decline over the past 30 years. Hyperglycaemia is the primary aetiological factor responsible for the development of diabetic kidney disease. Once hyperglycaemia becomes established, multiple pathophysiological disturbances, including hypertension, altered tubuloglomerular feedback, renal hypoxia, lipotoxicity, podocyte injury, inflammation, mitochondrial dysfunction, impaired autophagy and increased activity of the sodium-hydrogen exchanger, contribute to progressive glomerular sclerosis and the decline in glomerular filtration rate. The quantitative contribution of each of these abnormalities to the progression of diabetic kidney disease, as well as their role in type 1 and type 2 diabetes mellitus, remains to be determined. Sodium-glucose co-transporter 2 (SGLT2) inhibitors have a beneficial impact on many of these pathophysiological abnormalities; however, as several pathophysiological disturbances contribute to the onset and progression of diabetic kidney disease, multiple agents used in combination will likely be required to slow the progression of disease effectively. 10.1038/s41581-021-00393-8
    Therapeutic Potential of Mesenchymal Stem Cells in a Pre-Clinical Model of Diabetic Kidney Disease and Obesity. Sávio-Silva Christian,Soinski-Sousa Poliana E,Simplício-Filho Antônio,Bastos Rosana M C,Beyerstedt Stephany,Rangel Érika Bevilaqua International journal of molecular sciences Diabetic kidney disease (DKD) is a worldwide microvascular complication of type 2 diabetes mellitus (T2DM). From several pathological mechanisms involved in T2DM-DKD, we focused on mitochondria damage induced by hyperglycemia-driven reactive species oxygen (ROS) accumulation and verified whether mesenchymal stem cells (MSCs) anti-oxidative, anti-apoptotic, autophagy modulation, and pro-mitochondria homeostasis therapeutic potential curtailed T2DM-DKD progression. For that purpose, we grew immortalized glomerular mesangial cells (GMCs) in hyper glucose media containing hydrogen peroxide. MSCs prevented these cells from apoptosis-induced cell death, ROS accumulation, and mitochondria membrane potential impairment. Additionally, MSCs recovered GMCs' biogenesis and mitophagy-related gene expression that were downregulated by stress media. In BTBR mice, a robust model of T2DM-DKD and obesity, MSC therapy (1 × 10 cells, two doses 4-weeks apart, intra-peritoneal route) led to functional and structural kidney improvement in a time-dependent manner. Therefore, MSC-treated animals exhibited lower levels of urinary albumin-to-creatinine ratio, less mesangial expansion, higher number of podocytes, up-regulation of mitochondria-related survival genes, a decrease in autophagy hyper-activation, and a potential decrease in cleaved-caspase 3 expression. Collectively, these novel findings have important implications for the advancement of cell therapy and provide insights into cellular and molecular mechanisms of MSC-based therapy in T2DM-DKD setting. 10.3390/ijms22041546
    Astragaloside II Ameliorated Podocyte Injury and Mitochondrial Dysfunction in Streptozotocin-Induced Diabetic Rats. Su Jun,Gao Chongting,Xie Ling,Fan Ying,Shen Yilan,Huang Qunwei,Wang Niansong,Xu Youhua,Yang Nizhi,Gui Dingkun Frontiers in pharmacology Astragaloside II (AS II), a novel saponin purified from Astragalus membranes, has been reported to modulate the immune response, repair tissue injury, and prevent inflammatory response. However, the protective effects of AS II on podocyte injury in diabetic nephropathy (DN) have not been investigated yet. In this study, we aimed to investigate the beneficial effects of AS II on podocyte injury and mitochondrial dysfunction in DN. Diabetes was induced with streptozotocin (STZ) by intraperitoneal injection at 55 mg/kg in rats. Diabetic rats were randomly divided into four groups, namely, diabetic rats and diabetic rats treated with losartan (10 mg·kg·d) or AS II (3.2 and 6.4 mg·kg·d) for 9 weeks. Normal Sprague-Dawley rats were chosen as nondiabetic control group. Urinary albumin/creatinine ratio (ACR), biochemical parameters, renal histopathology and podocyte apoptosis, and morphological changes were evaluated. Expressions of mitochondrial dynamics-related and autophagy-related proteins, such as Mfn2, Fis1, P62, and LC3, as well as Nrf2, Keap1, PINK1, and Parkin, were examined by immunohistochemistry, western blot, and real-time PCR, respectively. Our results indicated that AS II ameliorated albuminuria, renal histopathology, and podocyte foot process effacement and podocyte apoptosis in diabetic rats. AS II also partially restored the renal expression of mitochondrial dynamics-related and autophagy-related proteins, including Mfn2, Fis1, P62, and LC3. AS II also increased the expression of PINK1 and Parkin associated with mitophagy in diabetic rats. Moreover, AS II facilitated antioxidative stress ability via increasing Nrf2 expression and decreasing Keap1 protein level. These results suggested that AS II ameliorated podocyte injury and mitochondrial dysfunction in diabetic rats partly through regulation of Nrf2 and PINK1 pathway. These important findings might provide an innovative therapeutic strategy for the treatment of DN. 10.3389/fphar.2021.638422
    Hyperglycemia alters mitochondrial respiration efficiency and mitophagy in human podocytes. Audzeyenka Irena,Rachubik Patrycja,Typiak Marlena,Kulesza Tomasz,Topolewska Anna,Rogacka Dorota,Angielski Stefan,Saleem Moin A,Piwkowska Agnieszka Experimental cell research Podocytes constitute the outer layer of the renal glomerular filtration barrier. Their energy requirements strongly depend on efficient oxidative respiration, which is tightly connected with mitochondrial dynamics. We hypothesized that hyperglycemia modulates energy metabolism in glomeruli and podocytes and contributes to the development of diabetic kidney disease. We found that oxygen consumption rates were severely reduced in glomeruli from diabetic rats and in human podocytes that were cultured in high glucose concentration (30 mM; HG). In these models, all of the mitochondrial respiratory parameters, including basal and maximal respiration, ATP production, and spare respiratory capacity, were significantly decreased. Podocytes that were treated with HG showed a fragmented mitochondrial network, together with a decrease in expression of the mitochondrial fusion markers MFN1, MFN2, and OPA1, and an increase in the activity of the fission marker DRP1. We showed that markers of mitochondrial biogenesis, such as PGC-1α and TFAM, decreased in HG-treated podocytes. Moreover, PINK1/parkin-dependent mitophagy was inhibited in these cells. These results provide evidence that hyperglycemia impairs mitochondrial dynamics and turnover, which may underlie the remarkable deterioration of mitochondrial respiration parameters in glomeruli and podocytes. 10.1016/j.yexcr.2021.112758
    AMPK agonist alleviate renal tubulointerstitial fibrosis via activating mitophagy in high fat and streptozotocin induced diabetic mice. Han Ya-Chun,Tang Shi-Qi,Liu Yu-Ting,Li Ai-Mei,Zhan Ming,Yang Ming,Song Na,Zhang Wei,Wu Xue-Qin,Peng Can-Hui,Zhang Hao,Yang Shikun Cell death & disease Renal tubulointerstitial fibrosis was a crucial pathological feature of diabetic nephropathy (DN), and renal tubular injury might associate with abnormal mitophagy. In this study, we investigated the effects and molecular mechanisms of AMPK agonist metformin on mitophagy and cellular injury in renal tubular cell under diabetic condition. The high fat diet (HFD) and streptozotocin (STZ)-induced type 2 diabetic mice model and HK-2 cells were used in this study. Metformin was administered in the drinking water (200 mg/kg/d) for 24 weeks. Renal tubulointerstitial lesions, oxidative stress and some indicators of mitophagy (e.g., LC3II, Pink1, and Parkin) were examined both in renal tissue and HK-2 cells. Additionally, compound C (an AMPK inhibitor) and Pink1 siRNA were applied to explore the molecular regulation mechanism of metformin on mitophagy. We found that the expression of p-AMPK, Pink1, Parkin, LC3II, and Atg5 in renal tissue of diabetic mice was decreased obviously. Metformin reduced the levels of serum creatinine, urine protein, and attenuated renal oxidative injury and fibrosis in HFD/STZ induced diabetic mice. In addition, Metformin reversed mitophagy dysfunction and the over-expression of NLRP3. In vitro pretreatment of HK-2 cells with AMPK inhibitor compound C or Pink1 siRNA negated the beneficial effects of metformin. Furthermore, we noted that metformin activated p-AMPK and promoted the translocation of Pink1 from the cytoplasm to mitochondria, then promoted the occurrence of mitophagy in HK-2 cells under HG/HFA ambience. Our results suggested for the first time that AMPK agonist metformin ameliorated renal oxidative stress and tubulointerstitial fibrosis in HFD/STZ-induced diabetic mice via activating mitophagy through a p-AMPK-Pink1-Parkin pathway. 10.1038/s41419-021-04184-8
    Calcium Signaling Mediates Cell Death and Crosstalk with Autophagy in Kidney Disease. Ning Bo,Guo Chuanzhi,Kong Anqi,Li Kongdong,Xie Yimin,Shi Haifeng,Gu Jie Cells The kidney is an important organ for the maintenance of Ca homeostasis in the body. However, disruption of Ca homeostasis will cause a series of kidney diseases, such as acute kidney injury (AKI), chronic kidney disease (CKD), renal ischemia/reperfusion (I/R) injury, autosomal dominant polycystic kidney disease (ADPKD), podocytopathy, and diabetic nephropathy. During the progression of kidney disease, Ca signaling plays key roles in various cell activities such as necrosis, apoptosis, eryptosis and autophagy. Importantly, there are complex Ca flux networks between the endoplasmic reticulum (ER), mitochondria and lysosomes which regulate intracellular Ca signaling in renal cells and contribute to kidney disease. In addition, Ca signaling also links the crosstalk between various cell deaths and autophagy under the stress of heavy metals or high glucose. In this regard, we present a review of Ca signaling in cell death and crosstalk with autophagy and its potential as a therapeutic target for the development of new and efficient drugs against kidney diseases. 10.3390/cells10113204
    Empagliflozin Enhances Autophagy, Mitochondrial Biogenesis, and Antioxidant Defense and Ameliorates Renal Ischemia/Reperfusion in Nondiabetic Rats. Oxidative medicine and cellular longevity BACKGROUND:Recent meta-analyses have shown that sodium-glucose cotransporter 2 (SGLT-2) inhibitors alleviate chronic kidney disease and acute kidney injury in diabetic patients. In this study, we aimed to investigate the effect of empagliflozin on renal ischemia/reperfusion (I/R) in nondiabetic rats and find the possible mechanisms. . Eighteen male Wistar rats were randomly divided into three groups, including healthy control, ischemic control, and empagliflozin-treated group. Thirty minutes of bilateral renal ischemia was induced by clamping the renal hilum. Forty-eight hours after reopening the clamps, rats' blood samples and tissue specimens were collected. Empagliflozin 10 mg/kg was administered by gavage, 2 hours before ischemia and 24 hours after the first dose. RESULTS:I/R injury led to a significant rise in serum creatinine and blood urea nitrogen which was significantly decreased after treatment with empagliflozin. Empagliflozin also alleviated tubulointerstitial and glomerular damage and significantly decreased tissue histology scores. Empagliflozin decreased the increased levels of malondialdehyde, interleukin 1, and tumor necrosis factor . SGLT2 inhibition increased the decreased expression of nuclear factor erythroid 2-related factor 2 and PPARG coactivator 1 alpha that conduct antioxidant defense and mitochondrial biogenesis, respectively. Furthermore, empagliflozin markedly increased LC3-II/LC3-I and bcl2/bax ratios, showing its beneficial effect on activation of autophagy and inhibition of apoptosis. Despite its effects on diabetic nephropathy, empagliflozin did not activate the Sestrin2/AMP-activated protein kinase pathway in this study. CONCLUSION:Empagliflozin improved renal I/R injury in nondiabetic rats in this study by promoting autophagy and mitochondrial biogenesis and attenuation of oxidative stress, inflammation, and apoptosis. 10.1155/2022/1197061
    Disruption of renal tubular mitochondrial quality control by Myo-inositol oxygenase in diabetic kidney disease. Zhan Ming,Usman Irtaza M,Sun Lin,Kanwar Yashpal S Journal of the American Society of Nephrology : JASN Diabetic kidney disease (DKD) is associated with oxidative stress and mitochondrial injury. Myo-inositol oxygenase (MIOX), a tubular-specific enzyme, modulates redox imbalance and apoptosis in tubular cells in diabetes, but these mechanisms remain unclear. We investigated the role of MIOX in perturbation of mitochondrial quality control, including mitochondrial dynamics and autophagy/mitophagy, under high-glucose (HG) ambience or a diabetic state. HK-2 or LLC-PK1 cells subjected to HG exhibited an upregulation of MIOX accompanied by mitochondrial fragmentation and depolarization, inhibition of autophagy/mitophagy, and altered expression of mitochondrial dynamic and mitophagic proteins. Furthermore, dysfunctional mitochondria accumulated in the cytoplasm, which coincided with increased reactive oxygen species generation, Bax activation, cytochrome C release, and apoptosis. Overexpression of MIOX in LLC-PK1 cells enhanced the effects of HG, whereas MIOX siRNA or d-glucarate, an inhibitor of MIOX, partially reversed these perturbations. Moreover, decreasing the expression of MIOX under HG ambience increased PTEN-induced putative kinase 1 expression and the dependent mitofusin-2-Parkin interaction. In tubules of diabetic mice, increased MIOX expression and mitochondrial fragmentation and defective autophagy were observed. Dietary supplementation of d-glucarate in diabetic mice decreased MIOX expression, attenuated tubular damage, and improved renal functions. Notably, d-glucarate administration also partially attenuated mitochondrial fragmentation, oxidative stress, and apoptosis and restored autophagy/mitophagy in the tubular cells of these mice. These results suggest a novel mechanism linking MIOX to impaired mitochondrial quality control during tubular injury in the pathogenesis of DKD and suggest d-glucarate as a potential therapeutic agent for the amelioration of DKD. 10.1681/ASN.2014050457
    [Effects of ammonium pyrrolidine dithiocarbamate (PDTC) on osteopontin expression and autophagy in tubular cells in streptozotocin-induced diabetic nephropathy rat]. Gao S,Jia J Y,Yan T K,Yu Y M,Shang W Y,Wei L,Zheng Z F,Fang P,Chang B C,Lin S Zhonghua yi xue za zhi To investigate the effects of ammonium pyrrolidine dithiocarbamate (PDTC) on tubulointerstitial inflammatory molecules and autophagy in diabetic nephropathy (DN) rats. Twenty-four male Sprague-Dawley rats were assigned to DN group (=6) and DN+ PDTC group (=6, PDTC, ip, 100 mg·kg·d), all received streptozotocin (STZ) 60 mg/kg intraperitoneally, and the other 12 rats were randomly divided into control group (=6) and PDTC group (=6). At the end of 12 weeks, after serum creatine (Scr) and 24-hour urinary protein were determined, rats were sacrificed to determined the renal pathological damages and the changes of nuclear factor (NF)-κB p65, p62, osteopontin (OPN), microtubule associated protein 1 light chain 3 (LC3)-Ⅱ/LC3-Ⅰ, nuclear p-NF-κB p65 by immunohistological stainning and Western blot, and ultrastructural changes of autophagic process was observed by electron microscopy (EM). Scr was similar among the four groups (>0.05). The levels of urinary protein in DN group and DN + PDTC group were significantly higher than the other two groups (all <0.01), but the level of urinary protein in DN + PDTC group was lower than that of DN group (<0.05). DN + PDTC group had less tubulointerstitial damage compared with DN group (<0.05). Among the four groups, expressions of p62, p65, OPN of tubulointerstitial area in DN group were significantly higher than that of the other groups (all <0.05), and Western blot showed that DN+ PDTC group had less expressions of NF-κB p65, nuclear p-p65, OPN and more expresssion of LC3-Ⅱ/LC3-Ⅰ compared with DN group (all <0.05), which were consistent with the decreased autophagic vacuoles and increased mitochondria dysfunction revealed by EM. Correlation analysis showed that renal LC3-Ⅱ/LC3-Ⅰ was negatively correlated the expressions of nuclear p-p65 and OPN (=-0.45, =0.02; =-0.50, =0.01), and p62 was positively correlated the expressions of nuclear p-p65 and OPN (=0.33, =0.01; =0.41, =0.01). Tubular NF-κB activation is closely related to autophagy dysfunction in DN rats, and PDTC may enhance autophagy activity in tubule cells by blocking NF-κB activity. 10.3760/cma.j.issn.0376-2491.2016.44.012
    The mitochondria-targeted antioxidant MitoQ ameliorated tubular injury mediated by mitophagy in diabetic kidney disease via Nrf2/PINK1. Xiao Li,Xu Xiaoxuan,Zhang Fan,Wang Ming,Xu Yan,Tang Dan,Wang Jiahui,Qin Yan,Liu Yu,Tang Chengyuan,He Liyu,Greka Anna,Zhou Zhiguang,Liu Fuyou,Dong Zheng,Sun Lin Redox biology Mitochondria play a crucial role in tubular injury in diabetic kidney disease (DKD). MitoQ is a mitochondria-targeted antioxidant that exerts protective effects in diabetic mice, but the mechanism underlying these effects is not clear. We demonstrated that mitochondrial abnormalities, such as defective mitophagy, mitochondrial reactive oxygen species (ROS) overexpression and mitochondrial fragmentation, occurred in the tubular cells of db/db mice, accompanied by reduced PINK and Parkin expression and increased apoptosis. These changes were partially reversed following an intraperitoneal injection of mitoQ. High glucose (HG) also induces deficient mitophagy, mitochondrial dysfunction and apoptosis in HK-2 cells, changes that were reversed by mitoQ. Moreover, mitoQ restored the expression, activity and translocation of HG-induced NF-E2-related factor 2 (Nrf2) and inhibited the expression of Kelch-like ECH-associated protein (Keap1), as well as the interaction between Nrf2 and Keap1. The reduced PINK and Parkin expression noted in HK-2 cells subjected to HG exposure was partially restored by mitoQ. This effect was abolished by Nrf2 siRNA and augmented by Keap1 siRNA. Transfection with Nrf2 siRNA or PINK siRNA in HK-2 cells exposed to HG conditions partially blocked the effects of mitoQ on mitophagy and tubular damage. These results suggest that mitoQ exerts beneficial effects on tubular injury in DKD via mitophagy and that mitochondrial quality control is mediated by Nrf2/PINK. 10.1016/j.redox.2016.12.022
    FoxO1 Promotes Mitophagy in the Podocytes of Diabetic Male Mice via the PINK1/Parkin Pathway. Li Wen,Du Mengmeng,Wang Qingzhu,Ma Xiaojun,Wu Lina,Guo Feng,Ji Hongfei,Huang Fengjuan,Qin Guijun Endocrinology We recently showed that forkhead-box class O1 (FoxO1) activation protects against high glucose-induced injury by preventing mitochondrial dysfunction in the rat kidney cortex. In addition, FoxO1 has been reported to mediate putative kinase 1 (PINK1) transcription and promote autophagy in response to mitochondrial oxidative stress in murine cardiomyocytes. In this study, we ascertained whether overexpressing FoxO1 in the kidney cortex reverses preestablished diabetic nephropathy in animal models. The effect of FoxO1 on mitophagy signaling pathways was evaluated in mouse podocytes. In vivo experiments were performed in male KM mice. A mouse model of streptozotocin (STZ)-induced type 1 diabetes (T1D) was used, and lentiviral vectors were injected into the kidney cortex to overexpress FoxO1. A mouse podocyte cell line was treated with high concentrations of glucose and genetically modified using lentiviral vectors. We found aberrant mitochondrial morphology and reduced adenosine triphosphate production. These mitochondrial abnormalities were due to decreased mitophagy via reduced phosphatase/tensin homolog on chromosome 10-induced PINK1/Parkin-dependent signaling. FoxO1 upregulation and PINK1/Parkin pathway activation can individually restore injured podocytes in STZ-induced T1D mice. Our results link the antioxidative activity of FoxO1 with PINK1/Parkin-induced mitophagy, indicating a novel role of FoxO1 in diabetic nephropathy. 10.1210/en.2016-1970
    Optineurin-mediated mitophagy protects renal tubular epithelial cells against accelerated senescence in diabetic nephropathy. Chen Kehong,Dai Huanzi,Yuan Junjie,Chen Jia,Lin Lirong,Zhang Weiwei,Wang Limin,Zhang Jianguo,Li Kailong,He Yani Cell death & disease Premature senescence is a key process in the progression of diabetic nephropathy (DN). Premature senescence of renal tubular epithelial cells (RTEC) in DN may result from the accumulation of damaged mitochondria. Mitophagy is the principal process that eliminates damaged mitochondria through PTEN-induced putative kinase 1 (PINK1)-mediated recruitment of optineurin (OPTN) to mitochondria. We aimed to examine the involvement of OPTN in mitophagy regulation of cellular senescence in RTEC in the context of DN. In vitro, the expression of senescence markers P16, P21, DcR2, SA-β-gal, SAHF, and insufficient mitophagic degradation marker (mitochondrial P62) in mouse RTECs increased after culture in 30 mM high-glucose (HG) conditions for 48 h. Mitochondrial fission/mitophagy inhibitor Mdivi-1 significantly enhanced RTEC senescence under HG conditions, whereas autophagy/mitophagy agonist Torin1 inhibited cell senescence. MitoTempo inhibited HG-induced mitochondrial reactive oxygen species and cell senescence with or without Mdivi-1. The expression of PINK1 and OPTN, two regulatory factors for mitophagosome formation, decreased significantly after HG stimulation. Overexpression of PINK1 did not enhance mitophagosome formation under HG conditions. OPTN silencing significantly inhibited HG-induced mitophagosome formation, and overexpression of OPTN relieved cellular senescence through promoting mitophagy. In clinical specimens, renal OPTN expression was gradually decreased with increased tubulointerstitial injury scores. OPTN-positive renal tubular cells did not express senescence marker P16. OPTN expression also negatively correlated with serum creatinine levels, and positively correlated with eGFR. Thus, OPTN-mediated mitophagy plays a crucial regulatory role in HG-induced RTEC senescence in DN. OPTN may, therefore, be a potential antisenescence factor in DN. 10.1038/s41419-017-0127-z
    Proximal Tubule Autophagy Differs in Type 1 and 2 Diabetes. Sakai Shinsuke,Yamamoto Takeshi,Takabatake Yoshitsugu,Takahashi Atsushi,Namba-Hamano Tomoko,Minami Satoshi,Fujimura Ryuta,Yonishi Hiroaki,Matsuda Jun,Hesaka Atsushi,Matsui Isao,Matsusaka Taiji,Niimura Fumio,Yanagita Motoko,Isaka Yoshitaka Journal of the American Society of Nephrology : JASN BACKGROUND:Evidence of a protective role of autophagy in kidney diseases has sparked interest in autophagy as a potential therapeutic strategy. However, understanding how the autophagic process is altered in each disorder is critically important in working toward therapeutic applications. METHODS:Using cultured kidney proximal tubule epithelial cells (PTECs) and diabetic mouse models, we investigated how autophagic activity differs in type 1 versus type 2 diabetic nephropathy. We explored nutrient signals regulating starvation-induced autophagy in PTECs and used autophagy-monitoring mice and PTEC-specific autophagy-deficient knockout mice to examine differences in autophagy status and autophagy's role in PTECs in streptozotocin (STZ)-treated type 1 and / type 2 diabetic nephropathy. We also examined the effects of rapamycin (an inhibitor of mammalian target of rapamycin [mTOR]) on vulnerability to ischemia-reperfusion injury. RESULTS:Administering insulin or amino acids, but not glucose, suppressed autophagy by activating mTOR signaling. In / mice, autophagy induction was suppressed even under starvation; in STZ-treated mice, autophagy was enhanced even under fed conditions but stagnated under starvation due to lysosomal stress. Using knockout mice with diabetes, we found that, in STZ-treated mice, activated autophagy counteracts mitochondrial damage and fibrosis in the kidneys, whereas in / mice, autophagic suppression jeopardizes kidney even in the autophagy-competent state. Rapamycin-induced pharmacologic autophagy produced opposite effects on ischemia-reperfusion injury in STZ-treated and mice. CONCLUSIONS:Autophagic activity in PTECs is mainly regulated by insulin. Consequently, autophagic activity differs in types 1 and 2 diabetic nephropathy, which should be considered when developing strategies to treat diabetic nephropathy by modulating autophagy. 10.1681/ASN.2018100983
    Diabetic nephropathy: an insight into molecular mechanisms and emerging therapies. Warren Annabelle M,Knudsen Søren T,Cooper Mark E Expert opinion on therapeutic targets : Diabetic kidney disease (DKD) is a major cause of morbidity and mortality in diabetes and is the most common cause of proteinuric and non-proteinuric forms of end-stage renal disease (ESRD). Control of risk factors such as blood glucose and blood pressure is not always achievable or effective. Significant research efforts have attempted to understand the pathophysiology of DKD and develop new therapies. : We review DKD pathophysiology in the context of existing and emerging therapies that affect hemodynamic and metabolic pathways. Renin-angiotensin system (RAS) inhibition has become standard care. Recent evidence for renoprotective activity of SGLT2 inhibitors and GLP-1 agonists is an exciting step forward while endothelin receptor blockade shows promise. Multiple metabolic pathways of DKD have been evaluated with varying success; including mitochondrial function, reactive oxygen species, NADPH oxidase (NOX), transcription factors (NF-B and Nrf2), advanced glycation, protein kinase C (PKC), aldose reductase, JAK-STAT, autophagy, apoptosis-signaling kinase 1 (ASK1), fibrosis and epigenetics. : There have been major advances in the understanding and treatment of DKD. SGLT2i and GLP-1 agonists have demonstrated renoprotection, with novel therapies under evaluation. Addressing the interaction between hemodynamic and metabolic pathways may help achieve prevention, attenuation or even reversal of DKD. 10.1080/14728222.2019.1624721
    Empagliflozin attenuates diabetic tubulopathy by improving mitochondrial fragmentation and autophagy. Lee Yu Ho,Kim Sang Hoon,Kang Jun Mo,Heo Jin Hyung,Kim Dong-Jin,Park Seon Hwa,Sung MinJi,Kim Jaehee,Oh Jisu,Yang Dong Ho,Lee Sang Ho,Lee So-Young American journal of physiology. Renal physiology We examined the effects of empagliflozin, a selective inhibitor of Na-glucose cotransporter 2, on mitochondrial quality control and autophagy in renal tubular cells in a diabetic environment in vivo and in vitro. Human renal proximal tubular cells (hRPTCs) were incubated under high-glucose conditions. Diabetes was induced with streptozotocin in male C57BL/6J mice. Improvements in mitochondrial biogenesis and balanced fusion-fission protein expression were noted in hRPTCs after treatment with empagliflozin in high-glucose media. Empagliflozin also increased autophagic activities in renal tubular cells in the high-glucose environment, which was accompanied with mammalian target of rapamycin inhibition. Moreover, reduced mitochondrial reactive oxygen species production and decreased apoptotic and fibrotic protein expression were observed in hRPTCs after treatment with empagliflozin, even in the hyperglycemic circumstance. Importantly, empagliflozin restored AMP-activated protein kinase-α phosphorylation and normalized levels of AMP-to-ATP ratios in hRPTCs subjected to a high-glucose environment, which suggests the way that empagliflozin is involved in mitochondrial quality control. Empagliflozin effectively suppressed Na-glucose cotransporter 2 expression and ameliorated renal morphological changes in the kidneys of streptozotocin-induced diabetic mice. Electron microscopy analysis showed that mitochondrial fragmentation was decreased and 8-hydroxy-2'-deoxyguanosine content was low in renal tubular cells of empagliflozin treatment groups compared with those of the diabetic control group. We suggest one mechanism related to the renoprotective actions of empagliflozin, which reverse mitochondrial dynamics and autophagy. 10.1152/ajprenal.00565.2018
    Protective role of podocyte autophagy against glomerular endothelial dysfunction in diabetes. Yoshibayashi Mamoru,Kume Shinji,Yasuda-Yamahara Mako,Yamahara Kosuke,Takeda Naoko,Osawa Norihisa,Chin-Kanasaki Masami,Nakae Yuki,Yokoi Hideki,Mukoyama Masashi,Asanuma Katsuhiko,Maegawa Hiroshi,Araki Shin-Ichi Biochemical and biophysical research communications To examine the cell-protective role of podocyte autophagy against glomerular endothelial dysfunction in diabetes, we analyzed the renal phenotype of tamoxifen (TM)-inducible podocyte-specific Atg5-deficient (iPodo-Atg5) mice with experimental endothelial dysfunction. In both control and iPodo-Atg5 mice, high fat diet (HFD) feeding induced glomerular endothelial damage characterized by decreased urinary nitric oxide (NO) excretion, collapsed endothelial fenestrae, and reduced endothelial glycocalyx. HFD-fed control mice showed slight albuminuria and nearly normal podocyte morphology. In contrast, HFD-fed iPodo-Atg5 mice developed massive albuminuria accompanied by severe podocyte injury that was observed predominantly in podocytes adjacent to damaged endothelial cells by scanning electron microscopy. Although podocyte-specific autophagy deficiency did not affect endothelial NO synthase deficiency-associated albuminuria, it markedly exacerbated albuminuria and severe podocyte morphological damage when the damage was induced by intravenous neuraminidase injection to remove glycocalyx from the endothelial surface. Furthermore, endoplasmic reticulum stress was accelerated in podocytes of iPodo-Atg5 mice stimulated with neuraminidase, and treatment with molecular chaperone tauroursodeoxycholic acid improved neuraminidase-induced severe albuminuria and podocyte injury. In conclusion, podocyte autophagy plays a renoprotective role against diabetes-related structural endothelial damage, providing an additional insight into the pathogenesis of massive proteinuria in diabetic nephropathy. 10.1016/j.bbrc.2020.02.088
    Role of Impaired Nutrient and Oxygen Deprivation Signaling and Deficient Autophagic Flux in Diabetic CKD Development: Implications for Understanding the Effects of Sodium-Glucose Cotransporter 2-Inhibitors. Packer Milton Journal of the American Society of Nephrology : JASN Growing evidence indicates that oxidative and endoplasmic reticular stress, which trigger changes in ion channels and inflammatory pathways that may undermine cellular homeostasis and survival, are critical determinants of injury in the diabetic kidney. Cells are normally able to mitigate these cellular stresses by maintaining high levels of autophagy, an intracellular lysosome-dependent degradative pathway that clears the cytoplasm of dysfunctional organelles. However, the capacity for autophagy in both podocytes and renal tubular cells is markedly impaired in type 2 diabetes, and this deficiency contributes importantly to the intensity of renal injury. The primary drivers of autophagy in states of nutrient and oxygen deprivation-sirtuin-1 (SIRT1), AMP-activated protein kinase (AMPK), and hypoxia-inducible factors (HIF-1 and HIF-2)-can exert renoprotective effects by promoting autophagic flux and by exerting direct effects on sodium transport and inflammasome activation. Type 2 diabetes is characterized by marked suppression of SIRT1 and AMPK, leading to a diminution in autophagic flux in glomerular podocytes and renal tubules and markedly increasing their susceptibility to renal injury. Importantly, because insulin acts to depress autophagic flux, these derangements in nutrient deprivation signaling are not ameliorated by antihyperglycemic drugs that enhance insulin secretion or signaling. Metformin is an established AMPK agonist that can promote autophagy, but its effects on the course of CKD have been demonstrated only in the experimental setting. In contrast, the effects of sodium-glucose cotransporter-2 (SGLT2) inhibitors may be related primarily to enhanced SIRT1 and HIF-2 signaling; this can explain the effects of SGLT2 inhibitors to promote ketonemia and erythrocytosis and potentially underlies their actions to increase autophagy and mute inflammation in the diabetic kidney. These distinctions may contribute importantly to the consistent benefit of SGLT2 inhibitors to slow the deterioration in glomerular function and reduce the risk of ESKD in large-scale randomized clinical trials of patients with type 2 diabetes. 10.1681/ASN.2020010010
    New Insights into the Pathogenesis of Diabetic Nephropathy: Proximal Renal Tubules Are Primary Target of Oxidative Stress in Diabetic Kidney. Haraguchi Ryuma,Kohara Yukihiro,Matsubayashi Kanako,Kitazawa Riko,Kitazawa Sohei Acta histochemica et cytochemica Diabetic nephropathy is a major source of end-stage renal failure, affecting about one-third cases of diabetes mellitus. It has long been accepted that diabetic nephropathy is mainly characterized by glomerular defects, while clinical observations have implied that renal tubular damage is closely linked to kidney dysfunction at the early stages of diabetic nephropathy. In this study, we conducted pathohistological analyses focusing on renal tubular lesions in the early-stage diabetic kidney with the use of a streptozotocin (STZ)-induced diabetes mellitus mouse model. The results revealed that histological alterations in renal tubules, shown by a vacuolar nucleic structure, accumulations of PAS-positive substance, and accelerated restoration stress, occur initially without the presence of glomerular lesions in the early-stage diabetic kidney, and that these tubular defects are localized mainly in proximal renal tubules. Moreover, enhanced expression of RAGE, suggesting an aberrant activation of AGEs-RAGE signaling pathway, and accumulation of oxidative modified mitochondria through the impaired autophagy/lysosome system, were also seen in the damaged diabetic proximal renal tubules. Our findings indicate that proximal tubular defects are the initial pathological events increasingly linked to the progression of diabetic nephropathy, and that controlling renal tubular damage could be an effective therapeutic strategy for the clinical treatment of diabetic nephropathy. 10.1267/ahc.20008
    Mechanism of progression of diabetic kidney disease mediated by podocyte mitochondrial injury. Su Jun,Ye Dan,Gao Chongting,Huang Qunwei,Gui Dingkun Molecular biology reports Diabetic kidney disease (DKD) is an important diabetic microvascular complication, which has become the main cause of end-stage renal disease (ESRD) all over the world. It is of great significance to find effective therapeutic targets and improve the prognosis of the disease. Traditionally, it is believed that the activation of the renin-angiotensin-aldosterone system (RAAS) is the main reason for the progression of DKD, but with the progress of research, it is known that the production of proteinuria in patients with DKD is also related to podocyte injury and loss. Many studies have shown that mitochondrial dysfunction in podocytes plays an important role in the occurrence and development of DKD, and oxidative stress is also the main pathway and common hub of diabetes to the occurrence and development of microvascular and macrovascular complications. Thus, the occurrence and progression of DKD is correlated with not only the activation of the RAAS, but also the damage of mitochondria, oxidative stress, and inflammatory mediators. Besides, diabetes-related metabolic disorders can also cause abnormalities in mitochondrial dynamics, autophagy and cellular signal transduction, which are intertwined in a complex way. Therefore, in this review, we mainly explore the mechanism and the latest research progress of podocyte mitochondria in DKD and summarize the main signal pathways involved in them. Thus, it provides feasible clinical application and future research suggestions for the prevention and treatment of DKD, which has important practical significance for the later treatment of patients with DKD. 10.1007/s11033-020-05749-0
    Mitophagy: A Novel Therapeutic Target for Treating DN. Yang Ming,Li Chenrui,Yang Shikun,Xiao Ying,Chen Wei,Gao Peng,Jiang Na,Xiong Shan,Wei Ling,Zhang Qin,Yang Jinfei,Zeng Lingfeng,Sun Lin Current medicinal chemistry Diabetic nephropathy (DN) is a common microvascular complication of diabetes and one of the leading causes of end-stage renal disease. Tubular damage is an early change and characteristic of DN, and mitochondrial dysfunction plays an important role in the development of DN. Therefore, the timely removal of damaged mitochondria in tubular cells is an effective treatment strategy for DN. Mitophagy is a type of selective autophagy that ensures the timely elimination of damaged mitochondria to protect cells from oxidative stress. In this review, we summarize our understanding of mitochondrial dysfunction and dynamic disorders in tubular cells in DN and the molecular mechanism of mitophagy. Finally, the role of mitophagy in DN and its feasibility as a therapeutic target for DN are discussed. 10.2174/0929867327666201006152656
    The Mitochondrial Kinase PINK1 in Diabetic Kidney Disease. Huang Chunling,Bian Ji,Cao Qinghua,Chen Xin-Ming,Pollock Carol A International journal of molecular sciences Mitochondria are critical organelles that play a key role in cellular metabolism, survival, and homeostasis. Mitochondrial dysfunction has been implicated in the pathogenesis of diabetic kidney disease. The function of mitochondria is critically regulated by several mitochondrial protein kinases, including the phosphatase and tensin homolog (PTEN)-induced kinase 1 (PINK1). The focus of PINK1 research has been centered on neuronal diseases. Recent studies have revealed a close link between PINK1 and many other diseases including kidney diseases. This review will provide a concise summary of PINK1 and its regulation of mitochondrial function in health and disease. The physiological role of PINK1 in the major cells involved in diabetic kidney disease including proximal tubular cells and podocytes will also be summarized. Collectively, these studies suggested that targeting PINK1 may offer a promising alternative for the treatment of diabetic kidney disease. 10.3390/ijms22041525
    Mitochondrial transfer from mesenchymal stem cells to macrophages restricts inflammation and alleviates kidney injury in diabetic nephropathy mice via PGC-1α activation. Yuan Yujia,Yuan Longhui,Li Lan,Liu Fei,Liu Jingping,Chen Younan,Cheng Jingqiu,Lu Yanrong Stem cells (Dayton, Ohio) Mesenchymal stem cells (MSCs) have fueled ample translation for treatment of immune-mediated diseases. Our previous study had demonstrated that MSCs could elicit macrophages (Mφ) into anti-inflammatory phenotypes, and alleviate kidney injury in diabetic nephropathy (DN) mice via improving mitochondrial function of Mφ, yet the specific mechanism was unclear. Recent evidence indicated that MSCs communicated with their microenvironment through exchanges of mitochondria. By a coculture system consisting of MSCs and Mφ, we showed that MSCs-derived mitochondria (MSCs-Mito) were transferred into Mφ, and the mitochondrial functions were improved, which contributed to M2 polarization. Furthermore, we found that MSCs-Mito transfer activated peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α)-mediated mitochondrial biogenesis. In addition, PGC-1α interacted with TFEB in high glucose-induced Mφ, leading to the elevated lysosome-autophagy, which was essential to removal of damaged mitochondria. As a result, in Mφ, the mitochondrial bioenergy and capacity to combat inflammatory response were enhanced. Whereas, the immune-regulatory activity of MSCs-Mito was significantly blocked in PGC-1α knockdown Mφ. More importantly, MSCs-Mito transfer could be observed in DN mice, and the adoptive transfer of MSCs-Mito educated Mφ (Mφ ) inhibited the inflammatory response and alleviated kidney injury. However, the kidney-protective effects of Mφ were abolished when the MSCs-Mito was impaired with rotenone, and the similar results were also observed when Mφ were transfected with sipgc-1α before administration. Collectively, these findings suggested that MSCs elicited Mφ into anti-inflammatory phenotype and ameliorated kidney injury through mitochondrial transfer in DN mice, and the effects were relied on PGC-1α-mediated mitochondrial biogenesis and PGC-1α/TFEB-mediated lysosome-autophagy. 10.1002/stem.3375
    Rapamycin protects against aristolochic acid nephropathy in mice by potentiating mammalian target of rapamycin‑mediated autophagy. Lin Fan,Liu Yunqi,Tang Lili,Xu Xiaohui,Zhang Xueli,Song Yifan,Chen Bicheng,Ren Yeping,Yang Xiangdong Molecular medicine reports Autophagy serves a crucial role in the etiology of kidney diseases, including drug‑induced renal impairment, inherited kidney disease, diabetic nephropathy and aristolochic acid nephropathy (AAN) and is, therefore, a potential target for treatment. We previously demonstrated that rapamycin could attenuate AAN in mice; however, the underlying mechanism remains to be elucidated. Therefore, whether the renal protective effect of rapamycin (an autophagy activator) is related to autophagy in aristolochic acid (AA)‑treated mice was of particular interest. The pathophysiological roles of rapamycin were investigated in AA‑induced nephrotoxicity in mice and the mechanisms of rapamycin action were explored by evaluating the modulation of autophagy in rapamycin‑treated mice and cultured renal tubular epithelial cells. Supplementation with rapamycin reversed AA‑induced kidney injury in mice and improved AA‑induced autophagy damage and . Mechanistically, rapamycin inhibited the renal expression of phosphorylated (p‑)mammalian target of rapamycin (mTOR) and p‑ribosomal S6 protein kinase 1, which in turn activated renal autophagy and decreased apoptosis, probably by removing AA‑elicited damaged mitochondria and misfolded proteins. The findings of the present study demonstrated that rapamycin protects against AA‑induced nephropathy by activating the mTOR‑autophagy axis and suggested that rapamycin may be a promising pharmacological target for the treatment of AAN. 10.3892/mmr.2021.12134
    Therapeutic potential of resveratrol in diabetic nephropathy according to molecular signaling. Salami Marziyeh,Salami Raziyeh,Mafi Alireza,Aarabi Mohammad-Hossein,Vakili Omid,Asemi Zatollah Current molecular pharmacology BACKGROUND:Diabetic nephropathy (DN) as a severe complication of diabetes mellitus (DM), is a crucial menace for human health and survival and remarkably elevates the healthcare systems' costs. Therefore, it is worth noting to identify novel preventive and therapeutic strategies to alleviate the disease conditions. Resveratrol, as a well-defined anti-diabetic/ antioxidant agent has capabilities to counteract diabetic complications. It has been predicted that resveratrol will be a fantastic natural polyphenol for diabetes therapy in the next few years. OBJECTIVE:Accordingly, the current review aims to depict the role of resveratrol in the regulation of different signaling pathways that are involved in the reactive oxygen species (ROS) production, inflammatory processes, autophagy, and mitochondrial dysfunction, as critical contributors to DN pathophysiology. RESULTS:The pathogenesis of DN can be multifactorial; hyperglycemia is one of the prominent risk factors of DN development that is closely related to oxidative stress. Resveratrol, as a well-defined polyphenol, has various biological and medicinal properties, including anti-diabetic, anti-inflammatory, and anti-oxidative effects. CONCLUSION:Resveratrol prevents kidney damages that are caused by oxidative stress, enhances antioxidant capacity, and attenuates the inflammatory and fibrotic responses. For this reason, resveratrol is considered an interesting target in DN research due to its therapeutic possibilities during diabetic disorders and renal protection. 10.2174/1874467215666211217122523
    Mitophagy regulates macrophage phenotype in diabetic nephropathy rats. Zhao Yu,Guo Yinfeng,Jiang Yuteng,Zhu Xiaodong,Liu Yuqiu,Zhang Xiaoliang Biochemical and biophysical research communications Imbalance of M1/M2 macrophages phenotype activation is a key point in diabetic nephropathy (DN). Macrophages mainly exhibit M1 phenotype, which contributes to the inflammation and fibrosis in DN. Studies indicate that autophage plays an important role in M1/M2 activation. However, the effect of mitophage on M1/M2 macrophage phenotype transformation in DN is unknown. This study investigates the role of mitophage on macrophage polarization in DN. In vivo experiments show that macrophages are exhibited to M1 phenotype and display a lower level of mitophagy in the kidney of streptozocin (STZ)-induced diabetic rats. Additionally, inducible nitric oxide synthase (iNOS) expression is positive correlated with the P62 expression, while negative correlated with LC3. Electronic microscope analysis shows mitochondria swelling, crista decrease and lysosome reduction in DN rats compared with NC rats. In vitro, RAW264.7 macrophages switch to M1 phenotype under high glucose conditions. Mitophagy is downregulated in such high glucose induced M1 macrophages. Furthermore, macrophages tend to switch to the M1 phenotype, expressing higher iNOS and TNF-α when impair mitophagy by 3-MA. Rapamycin, an activator of mitophagy, signifcantly blocks high-glucose induced M1 makers (iNOS and TNF-α) expression, meanwhile enhances M2 makers (MR and Arg-1) expression. These results demonstrate that mitophage participates in the regulation of M1/M2 macrophage phenotype in diabetic nephropathy. 10.1016/j.bbrc.2017.10.088
    SIRT3 Facilitates Amniotic Fluid Stem Cells to Repair Diabetic Nephropathy Through Protecting Mitochondrial Homeostasis by Modulation of Mitophagy. Feng Jianxun,Lu Chang,Dai Qin,Sheng Junqin,Xu Min Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology BACKGROUND/AIMS:Amniotic fluid stem cells (AFSCs) transplantation is a promising therapeutic strategy for diabetic nephropathy. Sirtuin3 (SIRT3) is a novel mitochondrial protective factor. In the present study, we aimed to investigate whether SIRT3 protects against hyperglycemia-induced AFSCs damage and enhances the therapeutic efficiency of AFSCs in diabetic nephropathy. METHODS:To establish the diabetic nephropathy model, db/ db mice were used. AFSCs were obtained and transplanted into the kidney tissue of db/ db mice. Gain-of-function assay with SIRT3 overexpression was performed in AFSCs via adenoviral transfections (Ad/SIRT3). Cellular viability and apoptosis were measured via MTT, TUNEL assay and western blotting. Mitochondrial function was assessed via JC1 staining, mPTP opening assay, mitochondrial respiratory function analysis, and immunofluorescence analysis of cyt-c. Mitophagy was assessed via western blotting and immunofluorescence analysis. Renal histopathology and morphometric analysis were conducted via H&E, Masson and PASM staining. Kidney function was detected via ELISA assay, western blotting and qPCR. RESULTS:SIRT3 was downregulated in AFSCs under high glucose stimulation, where its expression was positively correlated with AFSCs survival and proliferation. Regaining SIRT3 activated mitophagy protecting AFSCs against high glucose-induced apoptosis via preserving mitochondrial function. Transplanting SIRT3-overexpressing AFSCs in db/db mice improved the abnormalities in glucose metabolic parameters, including the levels of glucose, insulin, C-peptide, HbA1c and inflammatory markers. In addition, the engraftment of SIRT3-modified AFSCs also reversed renal function, decreased renal hypertrophy, and ameliorated renal histological changes in db/db mice. Functional studies confirmed that SIRT3-modified AFSCs promoted glomerulus survival and reduced renal fibrosis. CONCLUSION:Collectively, our results demonstrate that AFSCs may be a promising therapeutic treatment for ameliorating diabetes and the development of diabetic nephropathy and that the overexpression of SIRT3 in AFSCs may further increase the efficiency of stem cell-based therapy. 10.1159/000489194
    NR4A1 Promotes Diabetic Nephropathy by Activating Mff-Mediated Mitochondrial Fission and Suppressing Parkin-Mediated Mitophagy. Sheng Junqin,Li Hongyan,Dai Qin,Lu Chang,Xu Min,Zhang Jisheng,Feng Jianxun Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology BACKGROUND/AIMS:Disrupted mitochondrial dynamics, including excessive mitochondrial fission and mitophagy arrest, has been identified as a pathogenic factor in diabetic nephropathy (DN), although the upstream regulatory signal for mitochondrial fission activation and mitophagy arrest in the setting of DN remains unknown. METHODS:Wild-type (WT) mice and NR4A1 knockout (NR4A1-KO) mice were used to establish a DN model. Mitochondrial fission and mitophagy were evaluated by western blotting and immunofluorescence. Mitochondrial function was assessed by JC-1 staining, the mPTP opening assay, immunofluorescence and western blotting. Renal histopathology and morphometric analyses were conducted via H&E, Masson and PASM staining. Kidney function was evaluated via ELISA, western blotting and qPCR. RESULTS:In the present study, we found that nuclear receptor subfamily 4 group A member 1 (NR4A1) was actually activated by a chronic hyperglycemic stimulus. Higher NR4A1 expression was associated with glucose metabolism disorder, renal dysfunction, kidney hypertrophy, renal fibrosis, and glomerular apoptosis. At the molecular level, increased NR4A1 expression activated p53, and the latter selectively stimulated mitochondrial fission and inhibited mitophagy by modulating Mff and Parkin transcription. Excessive Mff-related mitochondrial fission caused mitochondrial oxidative stress, promoted mPTP opening, exacerbated proapoptotic protein leakage into the cytoplasm, and finally initiated mitochondria-dependent cellular apoptosis in the setting of diabetes. In addition, defective Parkin-mediated mitophagy repressed cellular ATP production and failed to correct the uncontrolled mitochondrial fission. However, NR4A1 knockdown interrupted the Mff-related mitochondrial fission and recused Parkin-mediated mitophagy, reducing the hyperglycemia-mediated mitochondrial damage and thus improving renal function. CONCLUSION:Overall, we have shown that NR4A1 functions as a novel malefactor in diabetic renal damage and operates by synchronously enhancing Mff-related mitochondrial fission and repressing Parkin-mediated mitophagy. Thus, finding strategies to regulate the balance of the NR4A1-p53 signaling pathway and mitochondrial homeostasis may be a therapeutic option for treating diabetic nephropathy in clinical practice. 10.1159/000492292
    Critical role of mitochondrial dysfunction and impaired mitophagy in diabetic nephropathy. Saxena Sugandh,Mathur Alpana,Kakkar Poonam Journal of cellular physiology Mitochondrial dynamics play a critical role in deciding the fate of a cell under normal and diseased condition. Recent surge of studies indicate their regulatory role in meeting energy demands in renal cells making them critical entities in the progression of diabetic nephropathy. Diabetes is remarkably associated with abnormal fuel metabolism, a basis for free radical generation, which if left unchecked may devastate the mitochondria structurally and functionally. Impaired mitochondrial function and their aberrant accumulation have been known to be involved in the manifestation of diabetic nephropathy, indicating perturbed balance of mitochondrial dynamics, and mitochondrial turnover. Mitochondrial dynamics emphasize the critical role of mitochondrial fission proteins such as mitochondrial fission 1, dynamin-related protein 1 and mitochondrial fission factor and fusion proteins including mitofusin-1, mitofusin-2 and optic atrophy 1. Clearance of dysfunctional mitochondria is aided by translocation of autophagy machinery to the impaired mitochondria and subsequent activation of mitophagy regulating proteins PTEN-induced putative kinase 1 and Parkin, for which mitochondrial fission is a prior event. In this review, we discuss recent progression in our understanding of the molecular mechanisms targeting reactive oxygen species mediated alterations in mitochondrial energetics, mitophagy related disorders, impaired glucose transport, tubular atrophy, and renal cell death. The molecular cross talks linking autophagy and renoprotection through an intervention of 5'-AMP-activated protein kinase, mammalian target of rapamycin, and SIRT1 factors are also highlighted here, as in-depth exploration of these pathways may help in deriving therapeutic strategies for managing diabetes provoked end-stage renal disease. 10.1002/jcp.28712