Up-regulation of miR-146b-3p protects septic mice with acute respiratory distress syndrome by inhibiting PI3K/AKT signaling pathway.
Liu Yao,Zhu Jin-Qiang,Jin Xiao-Hong,Dong Mei-Ping,Zheng Jun-Fen
Journal of bioenergetics and biomembranes
This study aimed to explore the role of miR-146b-3p in acute respiratory distress syndrome in septic mice. Ten mice were randomly selected as normal group (n = 10, without any treatment) and 60 septic mice with acute respiratory distress syndrome were divided into model group (n = 10, without any treatment), negative control (NC) mimic group (n = 10, injected with NC mimic), miR-146b-3p mimic group (n = 10, injected with miR-146b-3p mimic), si-NC group (n = 10, injected with PI3Kγ siRNA NC), si-PI3Kγ group (n = 10, injected with PI3Kγ silencing plasmid), and miR-146b-3p mimic + oe-PI3Kγ group (n = 10, injected with miR-146b-3p mimic + PI3Kγ overexpression plasmid). We found that miR-146b-3p negatively regulated PI3Kγ. Compared with normal group, model mice had decreased expression of miR-146b-3p, increased expressions of PI3Kγ, p-AKT, ASC, NLRP3 and Caspase-1 proteins, higher W/D ratio, and more serum IL-1β and IL-18 content (all P < 0.05). All indicators in miR-146b-3p mimic group and si-PI3Kγ group were significantly improved as compared to model group (all P < 0.05). Over-expression of PI3Kγ could weaken the treatment effect of miR-146b-3p mimic in model mice. Therefore, up-regulation of miR-146b-3p can inhibit PI3K/AKT signaling pathway to improve acute respiratory distress syndrome in septic mice.
Protective effect of cinnamic acid in endotoxin-poisoned mice.
Xu Feng,Wang Feng,Wen Taoqun,Sang Wentao,He Xinyu,Li Ling,Zeng Nan
Phytotherapy research : PTR
In this work, we aimed to evaluate the protective effect of cinnamic acid (CD) on lipopolysaccharide (LPS; Escherichia coli 055:B5)-induced endotoxin-poisoned mice and clarify the underlying mechanisms. The mice were administrated CD 5 d before 15 mg/kg LPS challenge. 12 hr later, thymus was separated for determination of thymus indexes. Lung and spleen tissues were collected for histologic examination and the wet/dry weight ratio of lung was calculated, and serum was acquired for tumor necrosis factor-α (TNF-α), interleukin (IL)-18, and IL-1β measurement. Moreover, the expression of NOD-like receptor (NLR) family, pyrin domain-containing 3 (NLRP3) inflammasome was determined in lung. CD increased the thymus indexes and decreased lung wet/dry weight ratio. In addition, CD improved the lung and spleen histopathological changes induced by LPS and decreased the number of neutrophils in lung tissues. CD also inhibited the pro-inflammatory cytokines (TNF-α, IL-18, and IL-1β) production in serum. Furthermore, CD suppressed the LPS-induced NLRP3, Caspase-1, and IL-1β mRNA expression in lung, as well as the expression of NLRP3 and Caspase-1 (p20) protein. CD may have protective effects in endotoxin-poisoned mice via inhibiting the activation of NLRP3 inflammasome, and can be considered as a potential therapeutic candidate for diseases involved in endotoxin poisoning such as sepsis.
P2X receptor antagonism ameliorates renal dysfunction in a rat model of sepsis.
Arulkumaran Nishkantha,Sixma Marije L,Pollen Sean,Ceravola Elias,Jentho Elisa,Prendecki Maria,Bass Paul S,Tam Frederick W K,Unwin Robert J,Singer Mervyn
Sepsis is a major clinical problem associated with significant organ dysfunction and high mortality. The ATP-sensitive P2X receptor activates the NLRP3 inflammasome and is a key component of the innate immune system. We used a fluid-resuscitated rat model of fecal peritonitis and acute kidney injury (AKI) to investigate the contribution of this purinergic receptor to renal dysfunction in sepsis. Six and 24 h time-points were chosen to represent early and established sepsis, respectively. A selective P2X receptor antagonist (A-438079) dissolved in dimethyl sulfoxide (DMSO) was infused 2 h following induction of sepsis. Compared with sham-operated animals, septic animals had significant increases in heart rate (-1(-4 to 8)% vs. 21(12-26)%; P = 0.003), fever (37.4(37.2-37.6)°C vs. 38.6(38.2-39.0)°C; P = 0.0009), and falls in serum albumin (29(27-30)g/L vs. 26(24-28); P = 0.0242). Serum IL-1β (0(0-10)(pg/mL) vs. 1671(1445-33778)(pg/mL); P < 0.001) and renal IL-1β (86(50-102)pg/mg protein vs. 200 (147-248)pg/mg protein; P = 0.0031) were significantly elevated in septic compared with sham-operated animals at 6 h. Serum creatinine was elevated in septic animals compared with sham-operated animals at 24 h (23(22-25) μmol/L vs. 28 (25-30)μmol/L; P = 0.0321). Renal IL-1β levels were significantly lower in A-438079-treated animals compared with untreated animals at 6 h (70(55-128)pg/mg protein vs. 200(147-248)pg/mg protein; P = 0.021). At 24 h, compared with untreated animals, A-438079-treated animals had more rapid resolution of tachycardia (22(13-36)% vs. -1(-6 to 7)%; P = 0.019) and fever (39.0(38.6-39.1)°C vs. 38.2(37.6-38.7)°C; P < 0.024), higher serum albumin (23(21-25)g/L vs. (27(25-28)g/L); P = 0.006), lower arterial lactate (3.2(2.5-4.3)mmol/L vs. 1.4(0.9-1.8)mmol/L; P = 0.037), and lower serum creatinine concentrations (28(25-30)μmol/L vs. 22(17-27)μmol/L; P = 0.019). P2X A treatment ameliorates the systemic inflammatory response and renal dysfunction in this clinically relevant model of sepsis-related AKI.
Critical role for calcium mobilization in activation of the NLRP3 inflammasome.
Murakami Tomohiko,Ockinger Johan,Yu Jiujiu,Byles Vanessa,McColl Aisleen,Hofer Aldebaran M,Horng Tiffany
Proceedings of the National Academy of Sciences of the United States of America
The NLRP3 (nucleotide-binding domain, leucine-rich-repeat-containing family, pyrin domain-containing 3) inflammasome mediates production of inflammatory mediators, such as IL-1β and IL-18, and as such is implicated in a variety of inflammatory processes, including infection, sepsis, autoinflammatory diseases, and metabolic diseases. The proximal steps in NLRP3 inflammasome activation are not well understood. Here we elucidate a critical role for Ca(2+) mobilization in activation of the NLRP3 inflammasome by multiple stimuli. We demonstrate that blocking Ca(2+) mobilization inhibits assembly and activation of the NLRP3 inflammasome complex, and that during ATP stimulation Ca(2+) signaling is pivotal in promoting mitochondrial damage. C/EPB homologous protein, a transcription factor that can modulate Ca(2+) release from the endoplasmic reticulum, amplifies NLRP3 inflammasome activation, thus linking endoplasmic reticulum stress to activation of the NLRP3 inflammasome. Our findings support a model for NLRP3 inflammasome activation by Ca(2+)-mediated mitochondrial damage.
Hyperin protects against LPS-induced acute kidney injury by inhibiting TLR4 and NLRP3 signaling pathways.
Chunzhi Gong,Zunfeng Li,Chengwei Qin,Xiangmei Bu,Jingui Yu
Hyperin is a flavonoid compound derived from Ericaceae, Guttifera, and Celastraceae that has been shown to have various biological effects, such as anti-inflammatory and anti-oxidant effects. However, there is no evidence to show the protective effects of hyperin on lipopolysaccharide (LPS)-induced acute kidney injury (AKI). Therefore, we investigated the protective effects and mechanism of hyperin on LPS-induced AKI in mice. The levels of TNF-α, IL-6, and IL-1β were tested by ELISA. The effects of hyperin on blood urea nitrogen (BUN) and serum creatinine were also detected. In addition, the expression of TLR4, NF-κB, and NLRP3 were detected by western blot analysis. The results showed that hyperin significantly inhibited LPS-induced TNF-α, IL-6, and IL-1β production. The levels of BUN and creatinine were also suppressed by hyperin. Furthermore, LPS-induced TLR4 expression and NF-κB activation were also inhibited by hyperin. In addition, treatment of hyperin dose-dependently inhibited LPS-induced NLRP3 signaling pathway. In conclusion, the results showed that hyperin inhibited LPS-induced inflammatory response by inhibiting TLR4 and NLRP3 signaling pathways. Hyperin has potential application prospects in the treatment of sepsis-induced AKI.
Nitric oxide suppresses NLRP3 inflammasome activation and protects against LPS-induced septic shock.
Mao Kairui,Chen Shuzhen,Chen Mingkuan,Ma Yonglei,Wang Yan,Huang Bo,He Zhengyu,Zeng Yan,Hu Yu,Sun Shuhui,Li Jing,Wu Xiaodong,Wang Xiangrui,Strober Warren,Chen Chang,Meng Guangxun,Sun Bing
Inflammasomes are multi-protein complexes that trigger the activation of caspase-1 and the maturation of interleukin-1β (IL-1β), yet the regulation of these complexes remains poorly characterized. Here we show that nitric oxide (NO) inhibited the NLRP3-mediated ASC pyroptosome formation, caspase-1 activation and IL-1β secretion in myeloid cells from both mice and humans. Meanwhile, endogenous NO derived from iNOS (inducible form of NO synthase) also negatively regulated NLRP3 inflammasome activation. Depletion of iNOS resulted in increased accumulation of dysfunctional mitochondria in response to LPS and ATP, which was responsible for the increased IL-1β production and caspase-1 activation. iNOS deficiency or pharmacological inhibition of NO production enhanced NLRP3-dependent cytokine production in vivo, thus increasing mortality from LPS-induced sepsis in mice, which was prevented by NLRP3 deficiency. Our results thus identify NO as a critical negative regulator of the NLRP3 inflammasome via the stabilization of mitochondria. This study has important implications for the design of new strategies to control NLRP3-related diseases.
Curcumin suppresses NLRP3 inflammasome activation and protects against LPS-induced septic shock.
Gong Zizhen,Zhou Jiefei,Li Hui,Gao Yanhong,Xu Congfeng,Zhao Shengnan,Chen Yingwei,Cai Wei,Wu Jin
Molecular nutrition & food research
SCOPE:The NLRP3 inflammasome responds to various pathogen-derived factors and danger-associated molecules, mediating IL-1β maturation, therefore is involved in multiple inflammatory diseases. Curcumin has been shown to possess strong anti-inflammatory activity, but the underlying mechanism is not fully understood. Here, we sought to investigate the role and mechanism of curcumin on the inhibition of mature IL-1β production via the regulation of NLRP3 inflammasome. METHODS AND RESULTS:Curcumin dramatically inhibited the production of mature IL-1β in LPS-primed macrophages triggered by multiple NLRP3 inflammasome activators, and also reduced the level of cleaved caspase-1 as measured by western blot and ELISA. Curcumin prevented K(+) efflux, the common trigger for NLRP3 inflammasome activation, and attenuated lysosomes disruption and intracellular ROS formation as well. The inhibition of NLRP3 inflammasome by curcumin was in part mediated via the suppression of extracellular regulated protein kinases phosphorylation. Furthermore, administration of curcumin significantly reduced peritoneal IL-1β and HMGB-1 concentration induced by LPS and improved the survival of mice suffering from lethal endotoxic shock. CONCLUSION:Curcumin potently inhibits the activation of NLRP3 inflammasome which may contribute to its anti-inflammatory activity. Our finding offers a mechanistic basis for the therapeutic potential of curcumin in septic shock and other NLRP3 inflammasome-driven diseases.
Ginsenoside Rg1 attenuates cardiomyocyte apoptosis and inflammation via the TLR4/NF-kB/NLRP3 pathway.
Luo Man,Yan Dongsheng,Sun Qingsong,Tao Jiali,Xu Liang,Sun Hong,Zhao Hongmei
Journal of cellular biochemistry
Sepsis-induced myocardial dysfunction (SIMD) causes high mortality in seriously ill patients. Ginsenoside Rg1 has been proven to have effective anti-inflammatory and antiapoptotic properties. However, the specific role of Rg1 in SIMD and the molecular mechanism remain unclear. Hence, we aimed to investigate the latent effects of ginsenoside Rg1 against SIMD and explore its underlying mechanisms. Male C57BL/6J mice and neonatal rat cardiomyocytes (NRCMs) were used as in vivo and in vitro models, respectively. Western blot analysis was used to detect the level of protein expression, and reverse transcription polymerase chain reaction was conducted to determine the messenger RNA expression of inflammatory factors. The terminal deoxynucleotidyl transferase-mediated nick end labeling assay and flow cytometry were used to determine the apoptosis rate. Echocardiography was performed to assess cardiac function. The results showed that Rg1 improved cardiac function and attenuated lipopolysaccharide (LPS)-induced apoptosis and inflammation in mice. In addition, in NRCMs, Rg1 downregulated the expression of LPS-induced inflammatory cytokines and reversed the increased expression of Toll-like receptor 4 (TLR4), nuclear factor-κB (NF-κB), and NOD-like receptor 3 (NLRP3). In addition, treatment with TLR4 small interfering RNA (siRNA), a p-NF-κB inhibitor, or NLRP3 siRNA suppressed LPS-induced apoptosis and inflammation. In conclusion, Rg1 can attenuate LPS-induced inflammation and apoptosis both in NRCMs and septic mice and restore impaired cardiac function. Moreover, Rg1 may exert its effect via blocking the TLR4/NF-κB/NLRP3 pathway.
Dexmedetomidine Enhances Autophagy α2-AR/AMPK/mTOR Pathway to Inhibit the Activation of NLRP3 Inflammasome and Subsequently Alleviates Lipopolysaccharide-Induced Acute Kidney Injury.
Yang Tianyuan,Feng Xiujing,Zhao Yuan,Zhang Haiyang,Cui Hailin,Wei Mian,Yang Haotian,Fan Honggang
Frontiers in pharmacology
Background:Acute kidney injury (AKI) is a severe complication of sepsis; however, no effective drugs have been found. Activation of the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome is a major pathogenic mechanism of AKI induced by lipopolysaccharide (LPS). Autophagy, a process of intracellular degradation related to renal homeostasis, effectively restricts inflammatory responses. Herein, we explored the potential protective mechanisms of dexmedetomidine (DEX), which has confirmed anti-inflammatory effects, on LPS-induced AKI. Methods:AKI was induced in rats by injecting 10 mg/kg of LPS intraperitoneally (i.p.). Wistar rats received intraperitoneal injections of DEX (30 µg/kg) 30 min before an intraperitoneal injection of LPS. Atipamezole (ATI) (250 µg/kg) and 3-methyladenine (3-MA) (15 mg/kg) were intraperitoneally injected 30 min before the DEX injection. Results:DEX significantly attenuated renal injury. Furthermore, DEX decreased activation of the NLRP3 inflammasome and expression of interleukins 1β and 18. In addition, autophagy-related protein and gene analysis indicated that DEX could significantly enhance autophagy. Finally, we verified the pharmacological effects of DEX on the 5'-adenosine monophosphate-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) pathway. Atip and 3-MA significantly reversed the protective effects of DEX. Conclusions:Our results suggest that the protective effects of DEX were mediated by enhanced autophagy the α-adrenoreceptor/AMPK/mTOR pathway, which decreased activation of the NLRP3 inflammasome. Above all, we verified the renal protective effects of DEX and offer a new treatment strategy for AKI.
Metformin protects against ischaemic myocardial injury by alleviating autophagy-ROS-NLRP3-mediated inflammatory response in macrophages.
Fei Qin,Ma Heng,Zou Jiang,Wang Wenmei,Zhu Lili,Deng Huafei,Meng Meng,Tan Sipin,Zhang Huali,Xiao Xianzhong,Wang Nian,Wang Kangkai
Journal of molecular and cellular cardiology
Myocardial ischaemia is usually accompanied by inflammatory response which plays a critical role in the myocardial healing and scar formation, while persistent inflammatory response contributes greatly to the myocardial remodeling and consequent heart failure. Metformin (Met), a widely used hypoglycemic drug, has increasingly been shown to exert remarkable cardioprotective effect on ischaemic myocardial injury such as acute myocardial infarction (AMI). However, the underlying mechanisms are still far from being fully understood. In this study, a mouse model of AMI was established through ligating the left anterior descending coronary artery (LAD), 100 mg/kg Met was given immediately after operation once daily for 3 days. It was demonstrated that Met effectively improved the cardiac haemodynamics (LVSP, LVEDP, +dp/dt, -dp/dt), diminished the infarct size, alleviated the disarrangement of myocardial cells and reduced the infiltration of inflammatory cells (macrophages, neutrophils and lymphocytes) in the heart of AMI mice. Mechanistically, Met decreased the expression of NLRP3 and enhanced the accumulation of LC3 puncta in F4/80-positive macrophages in the heart of AMI mice. Single cell suspension of cardiac macrophages was prepared from AMI mice and exhibited increased NLRP3 mRNA and protein expression. In contrast, Met decreased the expression of NLRP3 and p62, whereas increased the ratio of LC3II/LC3I. Additionally, both conditioned medium from H9c2 cardiomyocytes exposed to hydrogen peroxide (H9c2-HO-CM) and combination of mtDNA and ATP (mtDNA-ATP) increased the expression of NLRP3 and cleaved caspase-1 (p10) as well as intracellular ROS production in RAW264.7 macrophages, which were abrogated by Met treatment. Strikingly, chloroquine (CQ), 3-methyladenine (3-MA) and knockdown of autophagy-related gene (Atg5) abrogated the inhibitory effects of Met on H9c2-HO-CM and mtDNA-ATP-induced NLRP3 expression, release of IL-1β and IL-18 as well as ROS production in RAW264.7 macrophages. Collectively, these findings suggest that Met protects against ischaemic myocardial injury through alleviating autophagy-ROS-NLRP3 axis-mediated inflammatory response in macrophages.
miR-21 promotes NLRP3 inflammasome activation to mediate pyroptosis and endotoxic shock.
Xue Zhenyi,Xi Qing,Liu Hongkun,Guo Xiangdong,Zhang Jieyou,Zhang Zimu,Li Yan,Yang Guangze,Zhou Dongmei,Yang Huiyun,Zhang Lijuan,Zhang Qi,Gu Chao,Yang Juhong,Da Yurong,Yao Zhi,Duo Shuguang,Zhang Rongxin
Cell death & disease
miR-21 is aberrantly expressed, and plays a role in various types of tumors and many other diseases. However, the mechanism of miR-21 in LPS-induced septic shock is still unclear. In this study, we investigated the mechanism of miR-21 in LPS-induced pyroptosis and septic shock. Here, we show that miR-21 deficiency inhibited NLRP3, ASC, and caspase-1 expression, as well as inflammasome activation in myeloid cells from both mice and humans. We found that the NF-κB pathway was regulated by miR-21, and that A20 was a direct target of miR-21. Furthermore, miR-21 deficiency inhibited the ASC pyroptosome, which restrained caspase-1 activation and GSDMD cleavage, thereby preventing LPS-induced pyroptosis and septic shock. miR-21 deficiency resulted in an increase in A20, which led to decreased IL-1β production and caspase-1 activation. Caspase-1-mediated GSDMD cleavage was consequently decreased, which prevented pyroptosis in LPS-induced sepsis in mice. Our results demonstrate that miR-21 is a critical positive regulator of the NF-κB pathway and NLRP3 inflammasomes in pyroptosis and septic shock via A20. In addition, by analyzing published miRNA expression profiles in the Gene Expression Omnibus database, we found that the miR-21 levels in peripheral blood from patients with septic shock were elevated. Thus, miR-21 may serve as a potential treatment target in patients with septic shock.
Lipopolysaccharide (LPS) Aggravates High Glucose- and Hypoxia/Reoxygenation-Induced Injury through Activating ROS-Dependent NLRP3 Inflammasome-Mediated Pyroptosis in H9C2 Cardiomyocytes.
Qiu Zhen,He Yuhong,Ming Hao,Lei Shaoqing,Leng Yan,Xia Zhong-Yuan
Journal of diabetes research
Diabetes aggravates myocardial ischemia-reperfusion (I/R) injury because of the combination effects of changes in glucose and lipid energy metabolism, oxidative stress, and systemic inflammatory response. Studies have indicated that myocardial I/R may coincide and interact with sepsis and inflammation. However, the role of LPS in hypoxia/reoxygenation (H/R) injury in cardiomyocytes under high glucose conditions is still unclear. Our objective was to examine whether lipopolysaccharide (LPS) could aggravate high glucose- (HG-) and hypoxia/reoxygenation- (H/R-) induced injury by upregulating ROS production to activate NLRP3 inflammasome-mediated pyroptosis in H9C2 cardiomyocytes. H9C2 cardiomyocytes were exposed to HG (30 mM) condition with or without LPS, along with caspase-1 inhibitor (Ac-YVAD-CMK), inflammasome inhibitor (BAY11-7082), ROS scavenger N-acetylcysteine (NAC), or not for 24 h, then subjected to 4 h of hypoxia followed by 2 h of reoxygenation (H/R). The cell viability, lactate dehydrogenase (LDH) release, caspase-1 activity, and intracellular ROS production were detected by using assay kits. The incidence of pyroptosis was detected by calcein-AM/propidium iodide (PI) double staining kit. The concentrations of IL-1 and IL-18 in the supernatants were assessed by ELISA. The mRNA levels of NLRP3, ASC, and caspase-1 were detected by qRT-PCR. The protein levels of NF-B p65, NLRP3, ASC, cleaved caspase-1 (p10), IL-1, and IL-18 were detected by western blot. The results indicated that pretreatment LPS with 1 g/ml not 0.1 g/ml could efficiently aggravate HG and H/R injury by activating NLRP3 inflammasome to mediate pyroptosis in H9C2 cells, as evidenced by increased LDH release and decreased cell viability in the cells, and increased expression of NLRP3, ASC, cleaved caspase-1 (p10), IL-1, and IL-18. Meanwhile, Ac-YVAD-CMK, BAY11-7082, or NAC attenuated HG- and H/R-induced H9C2 cell injury with LPS stimulated by reversing the activation of NLRP3 inflammasome-mediated pyroptosis. In conclusion, LPS could increase the sensitivity of H9C2 cells to HG and H/R and aggravated HG- and H/R-induced H9C2 cell injury by promoting ROS production to induce NLRP3 inflammasome-mediated pyroptosis.
STING-IRF3 contributes to lipopolysaccharide-induced cardiac dysfunction, inflammation, apoptosis and pyroptosis by activating NLRP3.
Li Ning,Zhou Heng,Wu Haiming,Wu Qingqing,Duan Mingxia,Deng Wei,Tang Qizhu
Mountainous evidence suggests that inflammation, cardiomyocyte apoptosis and pyroptosis are involved in the development of sepsis and sepsis-induced cardiomyopathy (SIC). Stimulator of interferon genes (STING) is an indispensable molecule that could regulate inflammation and immune response in multiple diseases. However, the role of STING in cardiovascular disease, especially SIC remains unclear. This study was designed to investigate the potential molecular mechanisms of STING in lipopolysaccharide (LPS)-induced cardiac injury using STING global knockout mice. In wild type mice and cardiomyocytes, LPS stimulation triggered the perinuclear translocation of STING, which further bound to Type-I interferons (IFN) regulatory factor 3 (IRF3) and phosphorylated IRF3. Phosphorylated (P-) IRF3 subsequently translocated into nucleus and increased the expression of NOD-like receptor protein 3 (NLRP3). Knockout of STING in mice significantly improved survival rate and cardiac function, apart from suppressing myocardial and serum inflammatory cytokines, apoptosis, as well as cardiomyocyte pyroptosis. In vitro experiments revealed that NLRP3 overexpression by adenovirus could offset protective effects of STING knockdown in LPS-induced cardiomyocytes. Additionally, LPS stimulation also promoted the production of intracellular reactive oxygen (ROS), which further induced the NLRP3 translocation to the cytoplasm from the nucleus. Dissociative TXNIP could directly interact with cytoplasmic NLRP3 and form inflammasome, eventually triggering cardiomyocyte injury. Collectively, our findings disclose that STING deficiency could alleviate LPS-induced SIC in mice. Hence, targeting STING in cardiomyocytes may be a promising therapeutic strategy for preventing SIC.
Role of the Nucleotide-Binding Domain-Like Receptor Protein 3 Inflammasome in the Endothelial Dysfunction of Early Sepsis.
Luo Minghao,Meng Jiayu,Yan Jianghong,Shang Feifei,Zhang Ting,Lv Dingyi,Li Chang,Yang Xiyang,Luo Suxin
Endothelial dysfunction is responsible for multiple organ failure and the high mortality rate of sepsis. Nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome plays an essential role in the progression of sepsis. However, the role of NLRP3 inflammasome in the endothelial dysfunction of sepsis has not been fully elucidated. In this study, septic mice were induced by cecal ligation and puncture (CLP) operation, and human umbilical vein endothelial cells (HUVECs) were treated with lipopolysaccharide (LPS). The 24-h survival rate after CLP was observed. Vasodilation function of the aorta was detected by vascular reactivity experiments. Expression of p-eNOS, eNOS, TLR4, MYD88, p-p65, p65, p-ikbα, ikbα, iNOS, NLRP3, and IL-1β in the aorta and HUVECs were determined by Western blot. Our results suggest that the p-eNOS expression was downregulated, the endothelium-dependent relaxation function was impaired, and TLR4, MYD88, p-p65, p-ikbα, iNOS, NLRP3, and IL-1β expression increased after CLP. The onset of death was 12 h after CLP, and the mortality rate was nearly 50% at 24 h after operation. The decline of p-eNOS, endothelium-dependent vasodilation function, and survival rate significantly improved with NLRP3-specific inhibitor MCC950 intervention or NLRP3 knockout in CLP mice. The decrease of p-eNOS in HUVECs induced by LPS was alleviated when pretreated with MCC950 or interleukin-1 receptor antagonist (IL-1Ra). In summary, our results indicate that activation of the NLRP3 inflammasome contributes to the development of endothelial dysfunction of early sepsis in mice, suggesting its potential role as a therapeutic target for the treatment of sepsis.
Apelin protects against sepsis‑induced cardiomyopathy by inhibiting the TLR4 and NLRP3 signaling pathways.
Luo Qiancheng,Liu Guorong,Chen Guo,Guo Dongfeng,Xu Lei,Hang Min,Jin Mingming
International journal of molecular medicine
The mechanism underlying sepsis‑induced cardiomyopathy (SICM) remains unclear. The aim of the present study was therefore to illuminate the mechanisms and effects of apelin on SICM, using both patient clinical features and a sepsis rat model. A total of 73 adult patients with or without sepsis were analyzed. Male rats were used to generate the sepsis model through cecal ligation and puncture (CLP). The clinical analysis results demonstrated that sepsis induced cardiac dysfunction, including a decrease of left ventricular end‑diastolic dimension, fractional shortening, ejection fraction, left ventricular end‑systolic dimension, and stroke volume, compared with healthy controls. In addition, the results demonstrated that white blood cell count and inflammatory cytokine expression increased in sepsis patients compared with healthy controls. ELISA analyses revealed that apelin was upregulated following sepsis. The animal model study demonstrated that rats treated with apelin had significantly reduced mortality and suppressed sepsis‑induced myocardial damage and inflammatory responses, through suppression of activation of the Toll‑like receptor 4 (TLR4) and NLR family pyrin domain containing 3 (NLRP3) signaling pathways. Taken together, the present results suggested that apelin had a protective effect against sepsis‑induced cardiac impairment by attenuating TLR4 and NLRP3 signaling‑mediated inflammatory responses.
Overexpression of miR‑200a‑3p promoted inflammation in sepsis‑induced brain injury through ROS‑induced NLRP3.
Yu Jianhua,Chen Jinlong,Yang Hualing,Chen Sifang,Wang Zhanxiang
International journal of molecular medicine
Sepsis, a systemic inflammatory response syndrome induced by infection, is a common complication of trauma, burns, postoperative infection and critical disease, and is characterized by an acute onset and high fatality rate. The aim of the present study was to explore the possible molecular mechanisms of microRNA‑200a‑3p (miRNA‑200a‑3p) on inflammation during sepsis. Reverse transcription‑quantitative PCR and gene microarray were used to measure the expression of miRNA‑200a‑3p. Tumor necrosis factor‑α, interleukin (IL)‑1β, IL‑6 and IL‑18 were searched by ELISA. The related proteins expression was measured using western blotting. The expression of miRNA‑200a‑3p was markedly higher in the sepsis model when compared with the normal control group. In addition, the expression of miRNA‑200a‑3p was upregulated by the miRNA‑200a‑3p plasmid in human brain microvascular endothelial cells treated with lipopolysaccharide, which further induced inflammation via the induction of NLR family pyrin domain containing 3 (NLRP3) and suppression of Kelch like ECH associated protein (Keap)‑1/nuclear factor erythroid 2 like 2 (Nrf2)/heme oxygenase (HO)‑1. The inhibition of Keap1/Nrf2/HO‑1 attenuated the effects of anti‑miRNA‑200a‑3p on inflammation. However, the inhibition of NLRP3 attenuated the effects of miRNA‑200a‑3p on inflammation. In conclusion, to the best of our knowledge, the results of the present study demonstrated for the first time that overexpression of miRNA‑200a‑3p promoted inflammation in sepsis‑induced brain injury through reactive oxygen species‑induced NLRP3.
Sulfur dioxide attenuates sepsis-induced cardiac dysfunction via inhibition of NLRP3 inflammasome activation in rats.
Yang Lin,Zhang Hui,Chen Peili
Nitric oxide : biology and chemistry
OBJECTIVE:Sulfur dioxide (SO) plays an important role in maintaining homeostasis of cardiovascular system. This study was aimed to investigate cardioprotective effects of SO on in the rat and the underlying mechanism. METHODS AND RESULTS:Sepsis model induced by cecal ligation and puncture (CLP) in rats were used. SO donor (NaHSO/NaSO, 1:3 M/M) was administered intraperitoneally at a dose of 85 mg/kg. Primary neonatal rat cardiac ventricular myocytes (NRCMs) were stimulated with LPS (1 mg/mL) in presence or absence of different concentrations of SO (10, 50 and 100 μmol/L). SO donor could restore the decreased levels of SO in plasma and heart of septic rats. SO exhibited dramatic improvement in cardiac functions. At 24 h after CLP, SO treatments decreased the number of TUNEL-positive cells, Bax/Bcl-2 ratio and activity of caspase-3. Moreover CLP-induced inflammatory response was also relieved by SO. In NRCMs, SO could suppress the LPS-induced myocardial injury, leading to an increase in cell viability, a decrease in LDH and apoptotic rate. Western blot showed that the expression of TLR4, NLRP3, and Caspase-1 were obviously increased in myocardial tissue of CLP group or in NRCMs of LPS group, while SO significantly inhibited the CLP-induced or LPS-induced TLR4, NLRP3, and Caspase-1 expression. CONCLUSION:SO attenuated sepsis-induced cardiac dysfunction likely in association with the inhibiting inflammation via TLR4/NLRP3 signaling pathway.
Dihydromyricetin Alleviates Sepsis-Induced Acute Lung Injury through Inhibiting NLRP3 Inflammasome-Dependent Pyroptosis in Mice Model.
Wang Yu-Chang,Liu Qin-Xin,Zheng Qiang,Liu Tao,Xu Xi-E,Liu Xing-Hua,Gao Wei,Bai Xiang-Jun,Li Zhan-Fei
Increasing evidence demonstrates that pyroptosis, pro-inflammatory programmed cell death, is linked to acute lung injury (ALI). Dihydromyricetin (DHM) has been reported to exert anti-inflammatory effects by inhibiting NLRP3 inflammasome activation in vascular endothelial cells. However, the effects of DHM on NLRP3 inflammasome-induced pyroptosis in ALI remain elusive. In the present study, male BALB/c mice were subjected to cecal ligation and puncture (CLP), and DHM (50, 100, 150 mg/kg) was orally administered (once per day, for 3 days) 2 h after CLP. After 72 h, lung histopathology was examined, and the wet/dry (W/D) ratio, inflammatory infiltration, total protein concentration, total cell, and neutrophil counts were detected. Myeloperoxidase (MPO), interleukin (IL)-6, TNF-α, IL-1β, and IL-18 levels in bronchoalveolar lavage fluid (BALF) were measured by ELISA. Additionally, the expression of NLRP3 signaling pathway proteins were detected by Western blotting. The results revealed that in BALF, DHM (150 mg/kg) treatment significantly reduced the CLP-induced lung histopathological injury, inflammatory cell infiltration, total cell and neutrophil number, and total protein and albumin concentration. DHM treatment significantly inhibited the CLP-induced NLRP3 inflammasome pathway (NLRP3, ASC, caspase-1, gasdermin D (Gsdmd), IL-1β, and IL-18). In conclusion, these results demonstrate that DHM protects against CLP-induced ALI by inhibiting NLRP3 inflammasome activation and subsequent pyroptosis.
Melatonin alleviates sepsis-induced heart injury through activating the Nrf2 pathway and inhibiting the NLRP3 inflammasome.
Rahim Ibtissem,Sayed Ramy K,Fernández-Ortiz Marisol,Aranda-Martínez Paula,Guerra-Librero Ana,Fernández-Martínez José,Rusanova Iryna,Escames Germaine,Djerdjouri Bahia,Acuña-Castroviejo Darío
Naunyn-Schmiedeberg's archives of pharmacology
Melatonin improved the outcome of septic cardiomyopathy by inhibiting NLRP3 priming induced by reactive oxygen species. To get insights into these events, we studied the melatonin/Nrf2 antioxidant pathways during sepsis in the heart of NLRP3-deficient mice. Sepsis was induced by cecal ligation and puncture and melatonin was given at a dose of 30 mg/kg. Nuclear turnover of Nrf2 and p-Ser40 Nrf2 and expression of ho-1 were enhanced in nlrp3 and nlrp3 mice during sepsis. Sepsis caused higher mitochondria impairment, apoptotic and autophagic events in nlrp3 mice than in nlrp3 animals. These findings were accompanied by greater levels of Parkin and PINK-1, and lower Mfn2/Drp-1 ratio in nlrp3 than in nlrp3 mice during sepsis, supporting less mitophagy in the latter. Ultrastructural analysis of myocardial tissue further confirmed these observations. The activation of NLRP3 inflammasome accounted for most of the deleterious effects of sepsis, whereas the Nrf2-dependent antioxidative response activation in response to sepsis was unable to neutralize these events. In turn, melatonin further enhanced the Nrf2 response in both mice strains and reduced the NLRP3 inflammasome activation in nlrp3 mice, restoring myocardial homeostasis. The data support that the anti-inflammatory efficacy of melatonin against sepsis depends, at least in part, on Nrf2 activation.
The NLRP3 Inflammasome and Its Role in Sepsis Development.
Danielski Lucinéia Gainski,Giustina Amanda Della,Bonfante Sandra,Barichello Tatiana,Petronilho Fabricia
The pathophysiology of sepsis is extremely complex. During this disease, the exacerbation of the inflammatory response causes oxidative stress, alterations in mitochondrial energy dynamics, and multiple organ failure. Some studies have highlighted the important role of the NLRP3 inflammasome in sepsis. This inflammasome is a macromolecular protein complex that finely regulates the activation of caspase-1 and the production and secretion of potent pro-inflammatory cytokines such as IL-1β and IL-18. In this review, we elucidate evidences to understand the connection between sepsis development and the NLRP3 inflammasome, the most widely investigated member of this class of receptor.
The interplay between the gut microbiota and NLRP3 activation affects the severity of acute pancreatitis in mice.
Li Xueyang,He Cong,Li Nianshuang,Ding Ling,Chen Hongyan,Wan Jianhua,Yang Xiaoyu,Xia Liang,He Wenhua,Xiong Huifang,Shu Xu,Zhu Yin,Lu Nonghua
Early dysbiosis of the gut microbiota is associated with the severity of acute pancreatitis (AP), although the underlying mechanism is unclear. Here, we investigated the role of crosstalk between NLRP3 and the gut microbiota in the development of AP utilizing gut microbiota deficient mice, as well as NLRP3 knockout (KO) mouse models. Pancreatic damage and systemic inflammation were improved in antibiotic-treated (Abx) and germ-free (GF) mice, accompanied by weakened activity of the intestinal NLRP3 inflammasome. Interestingly, fecal microbiota transplantation (FMT) reactivated the intestinal NLRP3 inflammasome and exacerbated the disease in Abx and GF mice. Although the gut barrier in GF and Abx mice was disrupted, gut microbiota deficiency ameliorated the severity of AP, probably due to the reduction in bacterial translocation from the gut to the pancreas. The composition of the gut microbiota was significantly different between NLRP3 KO mice and wild-type (WT) mice at baseline, and there were alterations in response to the induction of AP. While a dramatic shift in the gut microbiota with overgrowth of was observed in WT mice suffering from AP, there was no significant change in NLRP3 KO mice with or without AP, suggesting that NLRP3 deficiency counteracts AP-induced microbial disturbance. With a strengthened gut barrier and decreased systemic inflammation, NLRP3 KO mice showed less severe AP, as revealed by reduced pancreatic neutrophilic infiltration and necrosis. Taken together, these results identified the bidirectional modulation between the gut microbiota and NLRP3 in the progression of AP, which suggests the interplay of the host and microbiome during AP.