Nrf2/Keap1 system regulates vascular smooth muscle cell apoptosis for vascular homeostasis: role in neointimal formation after vascular injury.
Ashino Takashi,Yamamoto Masayuki,Numazawa Satoshi
Abnormal increases in vascular smooth muscle cells (VSMCs) in the intimal region after a vascular injury is a key event in developing neointimal hyperplasia. To maintain vascular function, proliferation and apoptosis of VSMCs is tightly controlled during vascular remodeling. NF-E2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) system, a key component of the oxidative stress response that acts in maintaining homeostasis, plays an important role in neointimal hyperplasia after a vascular injury; however, the role of Nrf2/Keap1 in VSMC apoptosis has not been clarified. Here we report that 14 days after arterial injury in mice, TUNEL-positive VSMCs are detected in both the neointimal and medial layers. These layers contain cells expressing high levels of Nrf2 but low Keap1 expression. In VSMCs, Keap1 depletion induces features of apoptosis, such as positive TUNEL staining and annexin V binding. These changes are associated with an increased expression of nuclear Nrf2. Simultaneous Nrf2 depletion inhibits Keap1 depletion-induced apoptosis. At 14 days after the vascular injury, Nrf2-deficient mice demonstrated fewer TUNEL-positive cells and increased neointimal formation in the neointimal and medial areas. The results suggest that the Nrf2/Keap1 system regulates VSMC apoptosis during neointimal formation, thereby inhibiting neointimal hyperplasia after a vascular injury.
Dexamethasone induces rapid promotion of norepinephrine‑mediated vascular smooth muscle cell contraction.
Zhang Ting,Shi Wen-Lei,Tasker Jeffrey G,Zhou Jiang-Rui,Peng Yun-Li,Miao Chao-Yu,Yang Yong-Ji,Jiang Chun-Lei
Molecular medicine reports
The aim of the present study was to identify the rapid effect of dexamethasone (Dex) on norepinephrine (NE)‑mediated contraction of vascular smooth muscle cells (VSMCs) and to establish the underlying mechanism(s). Rat VSMCs were preincubated with lipopolysaccharide to simulate acute septic shock. Myosin light chain (MLC20) phosphorylation of VSMCs was detected by western blot analysis to observe the effects of Dex on NE‑mediated contraction. Activation of the RhoA/ RhoA kinase (ROCK), extracellular signal‑regulated kinase (ERK) and p38 signaling pathways was detected by western blot analysis to explore the mechanism. It was identified that Dex rapidly promoted NE‑induced phosphorylation of MLC20 in VSMCs and this effect may be non‑genomic. The RhoA/ROCK, ERK and p38 pathways were demonstrated to be important for the rapid effect of Dex‑induced promotion of NE‑mediated contraction in VSMCs. The present results indicate that Dex may rapidly reverse the hyporeactivity of vasoconstriction to NE in vitro and this effect may be mediated by specific non‑genomic mechanisms through increased activation of the RhoA/ROCK, ERK and p38 signaling pathways.
Vascular smooth muscle cell-selective peroxisome proliferator-activated receptor-gamma deletion leads to hypotension.
Chang Lin,Villacorta Luis,Zhang Jifeng,Garcia-Barrio Minerva T,Yang Kun,Hamblin Milton,Whitesall Steven E,D'Alecy Louis G,Chen Y Eugene
BACKGROUND:Peroxisome proliferator-activated receptor-gamma (PPARgamma) agonists are commonly used to treat diabetes, although their PPARgamma-dependent effects transcend their role as insulin sensitizers. Thiazolidinediones lower blood pressure (BP) in diabetic patients, whereas results from conventional/tissue-specific PPARgamma experimental models suggest an important pleiotropic role for PPARgamma in BP control. Little evidence is available on the molecular mechanisms underlying the role of vascular smooth muscle cell-specific PPARgamma in basal vascular tone. METHODS AND RESULTS:We show that vascular smooth muscle cell-selective deletion of PPARgamma impairs vasoactivity with an overall reduction in BP. Aortic contraction in response to norepinephrine is reduced and vasorelaxation is enhanced in response to beta-adrenergic receptor (beta-AdR) agonists in vitro. Similarly, vascular smooth muscle cell-selective PPARgamma knockout mice display a biphasic response to norepinephrine in BP, reversible on administration of beta-AdR blocker, and enhanced BP reduction on treatment with beta-AdR agonists. Consistent with enhanced beta2-AdR responsiveness, we found that the absence of PPARgamma in vascular smooth muscle cells increased beta2-AdR expression, possibly leading to the hypotensive phenotype during the rest phase. CONCLUSIONS:These data uncovered the beta2-AdR as a novel target of PPARgamma transcriptional repression in vascular smooth muscle cells and indicate that PPARgamma regulation of beta2-adrenergic signaling is important in the modulation of BP.
Isoproterenol inhibits angiotensin II-stimulated proliferation and reactive oxygen species production in vascular smooth muscle cells through heme oxygenase-1.
Kim Jung Eun,Kang Young Jin,Lee Kwang Youn,Choi Hyoung Chul
Biological & pharmaceutical bulletin
Heme oxygenase (HO)-1 is a well-known cytoprotectant against oxidative stress and exhibits an antiproliferative effect in vascular smooth muscle cells (VSMCs). The purpose of the present study was to test whether isoproterenol, one of the synthetic catecholamines having beta-adrenergic activity, affected angiotensin II (Ang II)-induced cell proliferation and reactive oxygen species (ROS) production. Also, the presumptive underlying signaling pathways in VSMCs were studied. Aortic VSMCs from 11-week-old male Sprague-Dawley rats were used. Isoproterenol dose-dependently increased HO-1 expression through beta(2)-adrenoceptor (AR) and protein kinase A (PKA) pathway, and isoproterenol concentration-dependently increased beta(2)-AR mRNA expression. Isoproterenol attenuated Ang II-induced cell proliferation, as evidenced by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay. This effect of isoproterenol was inhibited by pretreatment of the cells with beta(2)-AR antagonist butoxamine, PKA inhibitor H-89 and HO inhibitor Tin Protoporphyrin IX (SnPP IX), respectively. Isoproterenol inhibited phosphorylation level of Ang II-induced extracellular signal-regulated kinase (ERK1/2). Isoproterenol significantly inhibited Ang II-induced ROS production through the ERK1/2 pathway. These findings suggest that isoproterenol, via induction of HO-1, inhibits Ang II-stimulated proliferation and ROS production in cultured VSMCs.
Principal role of adenylyl cyclase 6 in K⁺ channel regulation and vasodilator signalling in vascular smooth muscle cells.
Nelson Carl P,Rainbow Richard D,Brignell Jennifer L,Perry Matthew D,Willets Jonathon M,Davies Noel W,Standen Nicholas B,Challiss R A John
AIMS:Membrane potential is a key determinant of vascular tone and many vasodilators act through the modulation of ion channel currents [e.g. the ATP-sensitive potassium channel (K(ATP))] involved in setting the membrane potential. Adenylyl cyclase (AC) isoenzymes are potentially important intermediaries in such vasodilator signalling pathways. Vascular smooth muscle cells (VSMCs) express multiple AC isoenzymes, but the reason for such redundancy is unknown. We investigated which of these isoenzymes are involved in vasodilator signalling and regulation of vascular ion channels important in modulating membrane potential. METHODS AND RESULTS:AC isoenzymes were selectively depleted (by >75%) by transfection of cultured VSMCs with selective short interfering RNA sequences. AC6 was the predominant isoenzyme involved in vasodilator-mediated cAMP accumulation in VSMCs, accounting for ∼60% of the total response to β-adrenoceptor (β-AR) stimulation. AC3 played a minor role in β-AR signalling, whereas AC5 made no significant contribution. AC6 was also the principal isoenzyme involved in β-AR-mediated protein kinase A (PKA) signalling (determined using the fluorescent biosensor for PKA activity, AKAR3) and the substantial β-AR/PKA-dependent enhancement of K(ATP) current. K(ATP) current was shown to play a vital role in setting the resting membrane potential and in mediating the hyperpolarization observed upon β-AR stimulation. CONCLUSION:AC6, but not the closely related AC5, plays a principal role in vasodilator signalling and regulation of the membrane potential in VSMCs. These findings identify AC6 as a vital component in the vasodilatory apparatus central to the control of blood pressure.
Effect of epinephrine on platelet-activating factor-stimulated human vascular smooth muscle cells.
Vadas Peter,Perelman Boris
The Journal of allergy and clinical immunology
BACKGROUND:Animal and human data show that platelet-activating factor (PAF) mediates the life-threatening manifestations of anaphylaxis. Although administration of epinephrine is the mainstay of therapy of acute anaphylaxis, the interaction between epinephrine and PAF has not been studied. In particular, the effect of the timing of epinephrine administration on the action of PAF has not been examined. OBJECTIVE:Using human vascular smooth muscle cells (HVSMCs), we examined the effect of timing of epinephrine addition on the action of PAF. METHODS:The effect of epinephrine on PAF-mediated prostaglandin E(2) (PGE(2)) release from human aortic smooth muscle cells was examined. Epinephrine was added at various times before and after PAF stimulation. RESULTS:HVSMCs stimulated with PAF released PGE(2) in a concentration- and time-dependent manner. Whereas preincubation of HVSMCs with epinephrine before the addition of PAF suppressed PGE(2) release, treatment with epinephrine after PAF stimulation was less effective with time after PAF stimulation. PGE(2) release was suppressed by means of preincubation with 8-bromo-cyclic AMP and forskolin. CONCLUSIONS:PAF induced PGE(2) release from HVSMCs in a concentration- and time-dependent manner, and early addition of epinephrine was essential for the control of PAF-induced PGE(2) release. Epinephrine was most effective when administered before stimulation with PAF but was progressively less effective with time after PAF stimulation.
Chlorogenic acid prevents isoproterenol-induced DNA damage in vascular smooth muscle cells.
Wang Jingshuai,Li Jiyang,Liu Jie,Xu Mengjiao,Tong Xiaowen,Wang Jianjun
Molecular medicine reports
Numerous clinical therapeutic agents have been identified as DNA damaging. The present study revealed that isoproterenol (Iso) resulted in DNA damage in vascular smooth muscle cells (VSMCs) and increased the levels of intracellular oxygen free radicals. Administration of chlorogenic acid (CGA) inhibited this effect. Pretreatment with CGA abrogated the increase in protein expression levels of γ‑H2A histone family member X, phosphorylated ataxia telangiectasia mutated, phosphorylated Rad3‑related protein, breast cancer 1 and C‑terminal Src homologous kinase induced by Iso. In addition, the increase in levels of intracellular reactive oxygen species (ROS) induced by Iso was inhibited by CGA pretreatment in a dose‑dependent manner. The results of the present study suggest that CGA may inhibit Iso‑induced VSMC damage via the suppression of ROS generation. Therefore, CGA may be a novel agent for the treatment of vascular diseases.
Inhibition of farnesyl pyrophosphate synthase prevents norepinephrine-induced fibrotic responses in vascular smooth muscle cells from spontaneously hypertensive rats.
Du Chang-Qing,Yang Lin,Yang Jian,Han Jie,Hu Xiao-Sheng,Wu Tao,Hu Shen-Jiang
Hypertension research : official journal of the Japanese Society of Hypertension
Both norepinephrine (NE) and connective tissue growth factor (CTGF) contribute to vascular fibrosis during hypertension. Recent studies indicate that farnesyl pyrophosphate synthase (FPPS) plays an important role in cardiac remodeling in hypertension. However, the role of FPPS in NE-induced fibrotic responses and related molecular mechanisms is unknown. Vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were stimulated with NE. The fibrotic responses were assessed by measuring CTGF, hydroxyproline (hyp), and α-1 procollagen I levels using Western blot, a hydroxyproline test kit, and real-time quantitative PCR assays, respectively. Ras activity was determined by a pull-down assay using a Ras activation assay kit and detected by Western blot. NE dose-dependently increased fibrosis in SHR-VSMCs, and this increase was significantly reduced by ibandronate, an inhibitor of FPPS. The addition of farnesol, but not geranylgeraniol, partially reversed the inhibitory effects of ibandronate. Furthermore, the anti-fibrotic effects of ibandronate could be mimicked by FTI-276 but not by GGTI-286. A pull-down assay showed that ibandronate reduced the NE-induced Ras activation. Moreover, ibandronate inhibited the NE-induced activation of p38, JNK, and ERK1/2. Only SB203580 (specific inhibitor of p38) diminished the NE-induced CTGF production. These results demonstrated that inhibiting FPPS prevents NE-induced fibrotic responses in SHR-VSMCs and that the Ras kinase and p38 pathways were the underlying mechanisms involved in this process.
Elevated plasma catecholamines functionally compensate for the reduced myogenic tone in smooth muscle STIM1 knockout mice but with deleterious cardiac effects.
Pichavaram Prahalathan,Yin Wen,Evanson Kirk W,Jaggar Jonathan H,Mancarella Salvatore
Aims:Stromal interaction molecule 1 (STIM1) has emerged as an important player in the regulation of growth and proliferation of smooth muscle cells. Therefore, we hypothesized that STIM1 plays a crucial role in the maintenance of vascular integrity. The objective of this study was to evaluate whether reduced expression of STIM1 could modify the structure and function of the vasculature, leading to changes in blood pressure (BP). Methods and results:Smooth muscle-specific STIM1 knockout (sm-STIM1 KO) in mice resulted in arteries with ∼80% reduced STIM1 protein expression as compared with control mice. Mesenteric vessels exposed to increasing transmural pressure revealed attenuated myogenic reactivity and reduced vasoconstrictor response to phenylephrine in sm-STIM1 KO arteries. BP monitored via telemetry in sm-STIM1 KO and matched controls did not reveal differences. However, heart rate was significantly increased in sm-STIM1 KO mice. Consistent with these findings, plasma catecholamine levels were higher in sm-STIM1 KO than in control mice. Increased sympathetic activity in sm-STIM1 KO mice was unmasked by apha1-adrenergic receptor inhibitor (prazosin) and by treatment with the ganglion-blocking agent, hexamethonium. Both treatments resulted in a greater reduction of BP in sm-STIM1 KO mice. Cytoskeleton of cultured smooth muscle cells was studied by immunocytochemistry using specific antibodies. Staining for actin and vinculin revealed significant alterations in the cytoskeletal architecture of cells isolated from sm-STIM1 KO arteries. Finally, although sm-STIM1 KO mice were protected from Ang II-induced hypertension, such treatment resulted in significant fibrosis and a rapid deterioration of cardiac function. Conclusions:STIM1 deletion in smooth muscle results in attenuated myogenic tone and cytoskeletal defects with detrimental effects on the mechanical properties of arterial tissue. Although BP is maintained by elevated circulating catecholamine, this compensatory stimulation has a deleterious long-term effect on the myocardium.
H19, a developmentally regulated gene, is reexpressed in rat vascular smooth muscle cells after injury.
Kim D K,Zhang L,Dzau V J,Pratt R E
The Journal of clinical investigation
Vascular smooth muscle cell migration, proliferation, and differentiation are central to blood vessel development. Since neointimal formation after vascular injury may require the reexpression of a smooth muscle developmental sequence, we examined the expression of H19, a developmentally regulated gene, in rat blood vessels. Expression of the H19 gene is associated with the differentiation process that takes place during development of many tissues. Consistent with this, H19 was highly expressed in the 1-d-old rat aorta but was undetectable in the adult. H19 transcripts were only minimally detected in uninjured carotid artery but were abundant at 7 and 14 d after injury and were localized by in situ hybridization, primarily to the neointima. H19 transcript were undetectable in proliferating neointimal cells in culture but became highly abundant in postconfluent, differentiated neointimal cells. H19 transcripts were only minimally expressed in adult medial smooth muscle cells grown under the identical conditions. Thus, H19 may play an important role in the normal development and differentiation of the blood vessel and in the phenotypic changes of the smooth muscle cells, which are associated with neointimal lesion formation. The vascular injury model may be a useful system to use in examining the function of H19.
Interleukin-2 is present in human blood vessels and released in biologically active form by heparanase.
Miller John D,Clabaugh Suzanne E,Smith Deandra R,Stevens R Brian,Wrenshall Lucile E
Immunology and cell biology
Interleukin-2 (IL-2) is a multifaceted cytokine with immunostimulatory and immunosuppressive properties. Our laboratory recently demonstrated that the availability of IL-2 is regulated, in part, by association with perlecan, a heparan sulfate proteoglycan. Given the abundance of perlecan in blood vessels, we asked whether IL-2 is present in vessel walls. Our results indicate that IL-2 is associated with endothelial and smooth muscle cells within the human arterial wall. This IL-2 is released by heparanase, and promotes the proliferation of an IL-2-dependent cell line. Given the presence of IL-2 in human arteries, we asked whether the large vessels of IL-2-deficient mice were normal. The aortas of IL-2-deficient mice exhibited a loss of smooth muscle cells, suggesting that IL-2 may contribute to their survival. In their entirety, these results suggest a here-to-fore unrecognized role of IL-2 in vascular biology, and have significant implications for both the immune and cardiovascular systems.
Expression of a Functional IL-2 Receptor in Vascular Smooth Muscle Cells.
Arumugam Prakash,Carroll Katie L,Berceli Scott A,Barnhill Spencer,Wrenshall Lucile E
Journal of immunology (Baltimore, Md. : 1950)
Many nonlymphoid cell types express at least two, if not all three, subunits of the IL-2R; although, compared with lymphocytes, relatively little is known about how IL-2 affects the function of nonlymphoid cells. The limited information available suggests that IL-2 has a substantial impact on cells such as gastrointestinal epithelial cells, endothelial cells, and fibroblasts. In a previous report from our laboratory, we noted that IL-2 and IL-2Rβ-deficient mice lose smooth muscle cells over time, eventually resulting in aneurysmal aortas and ectatic esophagi. This finding, combined with our work showing that IL-2 surrounds vascular smooth muscle cells by association with perlecan, led us to ask whether vascular smooth muscle cells express an IL-2R. Toward this end, we reported the expression of IL-2Rβ on human and murine vascular smooth muscle cells. We now report that vascular smooth muscle cells express all three subunits of the IL-2R, and that expression of IL-2Rα varies with vascular smooth muscle cell phenotype. Furthermore, we show that, through a functional IL-2R, IL-2 initiates signaling pathways and impacts vascular smooth muscle cell function. Finally, we demonstrate that IL-2 expression increases upon initiation of conditions that promote intimal hyperplasia, suggesting a mechanism by which the IL-2/IL-2R system may impact this widespread vascular pathology.
Everolimus Rescues the Phenotype of Elastin Insufficiency in Patient Induced Pluripotent Stem Cell-Derived Vascular Smooth Muscle Cells.
Kinnear Caroline,Agrawal Rahul,Loo Caitlin,Pahnke Aric,Rodrigues Deivid Carvalho,Thompson Tadeo,Akinrinade Oyediran,Ahadian Samad,Keeley Fred,Radisic Milica,Mital Seema,Ellis James
Arteriosclerosis, thrombosis, and vascular biology
OBJECTIVE:Elastin gene deletion or mutation leads to arterial stenoses due to vascular smooth muscle cell (SMC) proliferation. Human induced pluripotent stem cells-derived SMCs can model the elastin insufficiency phenotype in vitro but show only partial rescue with rapamycin. Our objective was to identify drug candidates with superior efficacy in rescuing the SMC phenotype in elastin insufficiency patients. Approach and Results: SMCs generated from induced pluripotent stem cells from 5 elastin insufficiency patients with severe recurrent vascular stenoses (3 Williams syndrome and 2 elastin mutations) were phenotypically immature, hyperproliferative, poorly responsive to endothelin, and exerted reduced tension in 3-dimensional smooth muscle biowires. Elastin mRNA and protein were reduced in SMCs from patients compared to healthy control SMCs. Fourteen drug candidates were tested on patient SMCs. Of the mammalian target of rapamycin inhibitors studied, everolimus restored differentiation, rescued proliferation, and improved endothelin-induced calcium flux in all patient SMCs except one Williams syndrome. Of the calcium channel blockers, verapamil increased SMC differentiation and reduced proliferation in Williams syndrome patient cells but not in elastin mutation patients and had no effect on endothelin response. Combination treatment with everolimus and verapamil was not superior to everolimus alone. Other drug candidates had limited efficacy. CONCLUSIONS:Everolimus caused the most consistent improvement in SMC differentiation, proliferation and in SMC function in patients with both syndromic and nonsyndromic elastin insufficiency, and offers the best candidate for drug repurposing for treatment of elastin insufficiency associated vasculopathy.
Av3 Single-Stranded DNA Aptamer Attenuates Vascular Smooth Muscle Cell Proliferation and Migration via Ras-PI3K/MAPK Pathway.
Wu Hong-Bing,Wang Zhi-Wei,Shi Feng,Ren Zong-Li,Li Luo-Cheng,Hu Xiao-Ping,Hu Rui,Li Bo-Wen
Objectives:To observe the effect of av3 single-stranded (ss) DNA on proliferation and migration of vascular smooth muscle cells (VSMCs) and its potential mechanism. Background:Percutaneous transluminal coronary angioplasty (PTCA) is currently the preferred method for the treatment of coronary heart disease. However, vascular restenosis still occurs after PTCA treatment, severely affecting the clinical efficacy of PTCA. Integrin av3 single-stranded (ss) DNA on proliferation and migration of vascular smooth muscle cells (VSMCs) and its potential mechanism. Methods:In this experiment, we used systematic evolution of ligands by exponential enrichment (SELEX) to screen out av3 single-stranded (ss) DNA on proliferation and migration of vascular smooth muscle cells (VSMCs) and its potential mechanism. 3 single-stranded (ss) DNA on proliferation and migration of vascular smooth muscle cells (VSMCs) and its potential mechanism. 3 single-stranded (ss) DNA on proliferation and migration of vascular smooth muscle cells (VSMCs) and its potential mechanism. 3 single-stranded (ss) DNA on proliferation and migration of vascular smooth muscle cells (VSMCs) and its potential mechanism. Results:In the present study, we found that av3 single-stranded (ss) DNA on proliferation and migration of vascular smooth muscle cells (VSMCs) and its potential mechanism. < 0.05). Av3 single-stranded (ss) DNA on proliferation and migration of vascular smooth muscle cells (VSMCs) and its potential mechanism. < 0.05). Av < 0.05). Av. Conclusions:The findings suggest that av3 ssDNA inhibited the proliferation and migration of VSMCs by suppressing the activation of Ras-PI3K/MAPK signaling.3 single-stranded (ss) DNA on proliferation and migration of vascular smooth muscle cells (VSMCs) and its potential mechanism.
LncRNA HCG18 is critical for vascular smooth muscle cell proliferation and phenotypic switching.
Lu Yanjiao,Guo Jingjing,Zhu Shengnan,Zhang Han,Zhu Qing,Li Yanming
Previous studies have shown that some specific long non-coding RNAs are dysregulated in vascular walls and abnormally expressed in vascular disease. LncRNA HLA complex group 18 (HCG18) is a member of the HLA complex group, which has been rarely investigated in human diseases. In this study, we aimed to investigate the role of HCG in vascular smooth muscle cells. HCG18 was over-expressed by adenovirus transfection and knocked down in vascular smooth muscle cells by shRNA. Cell proliferation was detected by CCK-8 assays. Flow cytometry was employed to test the impacts of HCG18 on vascular smooth muscle apoptotic cells. The expression of associated genes in protein and mRNA levels was detected by western blotting, immunofluorescence and qRT-PCR. The interactions between HCG18 and fused in sarcoma (FUS) were confirmed by RNA EMSA and RIP assays. The expression of serum HCG18 was decreased in hypertensive patients and PDGF-BB-treated vascular smooth muscle cells. HCG18 inhibited proliferation and induced apoptotic cells in vascular smooth muscle cells. In addition, we also found that HCG18 can inhibit vascular smooth muscle cell phenotypic switching from a contractile to a secretory phenotype. Finally, our results showed that HCG18 enhanced apoptotic cells by directly binding with FUS. Our findings reveal that HCG18 is involved in the regulation of proliferation, apoptosis and the expression levels of markers of the contractile and synthetic phenotype.
Flow-induced, inflammation-mediated arterial wall remodeling in the formation and progression of intracranial aneurysms.
Frösen Juhana,Cebral Juan,Robertson Anne M,Aoki Tomohiro
OBJECTIVE:Unruptured intracranial aneurysms (UIAs) are relatively common lesions that may cause devastating intracranial hemorrhage, thus producing considerable suffering and anxiety in those affected by the disease or an increased likelihood of developing it. Advances in the knowledge of the pathobiology behind intracranial aneurysm (IA) formation, progression, and rupture have led to preclinical testing of drug therapies that would prevent IA formation or progression. In parallel, novel biologically based diagnostic tools to estimate rupture risk are approaching clinical use. Arterial wall remodeling, triggered by flow and intramural stresses and mediated by inflammation, is relevant to both. METHODS:This review discusses the basis of flow-driven vessel remodeling and translates that knowledge to the observations made on the mechanisms of IA initiation and progression on studies using animal models of induced IA formation, study of human IA tissue samples, and study of patient-derived computational fluid dynamics models. RESULTS:Blood flow conditions leading to high wall shear stress (WSS) activate proinflammatory signaling in endothelial cells that recruits macrophages to the site exposed to high WSS, especially through macrophage chemoattractant protein 1 (MCP1). This macrophage infiltration leads to protease expression, which disrupts the internal elastic lamina and collagen matrix, leading to focal outward bulging of the wall and IA initiation. For the IA to grow, collagen remodeling and smooth muscle cell (SMC) proliferation are essential, because the fact that collagen does not distend much prevents the passive dilation of a focal weakness to a sizable IA. Chronic macrophage infiltration of the IA wall promotes this SMC-mediated growth and is a potential target for drug therapy. Once the IA wall grows, it is subjected to changes in wall tension and flow conditions as a result of the change in geometry and has to remodel accordingly to avoid rupture. Flow affects this remodeling process. CONCLUSIONS:Flow triggers an inflammatory reaction that predisposes the arterial wall to IA initiation and growth and affects the associated remodeling of the UIA wall. This chronic inflammation is a putative target for drug therapy that would stabilize UIAs or prevent UIA formation. Moreover, once this coupling between IA wall remodeling and flow is understood, data from patient-specific flow models can be gathered as part of the diagnostic workup and utilized to improve risk assessment for UIA initiation, progression, and eventual rupture.
Smooth muscle cells of intracranial vessels: from development to disease.
Frösen Juhana,Joutel Anne
Cerebrovascular diseases that cause ischaemic or haemorrhagic stroke with subsequent loss of life or functional capacity due to damage of the brain tissue are among the leading causes of human suffering and economic burden inflicted by diseases in the developed world. Diseases affecting intracranial vessels are significant contributors to ischaemic and haemorrhagic strokes. Brain arteriovenous malformations, which are a collection of abnormal blood vessels connecting arteries to veins, are the most common cause of intracranial haemorrhage in children and young adults. Saccular intracranial aneurysms, which are pathological saccular dilations mainly occurring at bifurcations of the large intracranial arteries near the circle of Willis, are highly prevalent in the middle-aged population, causing significant anxiety and concern; their rupture, although rare, is a significant cause of intracranial haemorrhage in those past middle age that is associated with a very sinister prognosis. Cerebral small-vessel disease, which comprise all pathological processes affecting vessels <500 microns in diameter, account for the majority of intracerebral haemorrhages and ∼25% of ischaemic strokes and 45% of dementias in the elderly. In this review, we summarize the developmental, structural, and functional features of intracranial vessels. We then describe the role of smooth muscle cells in brain arteriovenous malformations, intracranial aneurysms, and small-vessel diseases, and discuss how the peculiar ontogeny, structure, and function of intracranial vessels are related to the development of these diseases.
Elastic fibres and vascular structure in hypertension.
Arribas Silvia M,Hinek Aleksander,González M Carmen
Pharmacology & therapeutics
Blood vessels are dynamic structures composed of cells and extracellular matrix (ECM), which are in continuous cross-talk with each other. Thus, cellular changes in phenotype or in proliferation/death rate affect ECM synthesis. In turn, ECM elements not only provide the structural framework for vascular cells, but they also modulate cellular function through specific receptors. These ECM-cell interactions, together with neurotransmitters, hormones and the mechanical forces imposed by the heart, modulate the structural organization of the vascular wall. It is not surprising that pathological states related to alterations in the nervous, humoral or haemodynamic environment-such as hypertension-are associated with vascular wall remodeling, which, in the end, is deleterious for cardiovascular function. However, the question remains whether these structural alterations are simply a consequence of the disease or if there are early cellular or ECM alterations-determined either genetically or by environmental factors-that can predispose to vascular remodeling independent of hypertension. Elastic fibres might be key elements in the pathophysiology of hypertensive vascular remodeling. In addition to the well known effects of hypertension on elastic fibre fatigue and accelerated degradation, leading to loss of arterial wall resilience, recent investigations have highlighted new roles for individual components of elastic fibres and their degradation products. These elements can act as signal transducers and regulate cellular proliferation, migration, phenotype, and ECM degradation. In this paper, we review current knowledge regarding components of elastic fibres and discuss their possible pathomechanistic associations with vascular structural abnormalities and with hypertension development or progression.
Injected matrix stimulates myogenesis and regeneration of mouse skeletal muscle after ischaemic injury.
Kuraitis D,Ebadi D,Zhang P,Rizzuto E,Vulesevic B,Padavan D T,Al Madhoun A,McEwan K A,Sofrenovic T,Nicholson K,Whitman S C,Mesana T G,Skerjanc I S,Musarò A,Ruel M,Suuronen E J
European cells & materials
Biomaterial-guided regeneration represents a novel approach for the treatment of myopathies. Revascularisation and the intramuscular extracellular matrix are important factors in stimulating myogenesis and regenerating muscle damaged by ischaemia. In this study, we used an injectable collagen matrix, enhanced with sialyl LewisX (sLeX), to guide skeletal muscle differentiation and regeneration. The elastic properties of collagen and sLeX-collagen matrices were similar to those of skeletal muscle, and culture of pluripotent mESCs on the matrices promoted their differentiation into myocyte-like cells expressing Pax3, MHC3, myogenin and Myf5. The regenerative properties of matrices were evaluated in ischaemic mouse hind-limbs. Treatment with the sLeX-matrix augmented the production of myogenic-mediated factors insulin-like growth factor (IGF)-1, and IGF binding protein-2 and -5 after 3 days. This was followed by muscle regeneration, including a greater number of regenerating myofibres and increased transcription of Six1, M-cadherin, myogenin and Myf5 after 10 days. Simultaneously, the sLeX-matrix promoted increased mobilisation and engraftment of bone marrow-derived progenitor cells, the development of larger arterioles and the restoration of tissue perfusion. Both matrix treatments tended to reduce maximal forces of ischaemic solei muscles, but sLeX-matrix lessened this loss of force and also prevented muscle fatigue. Only sLeX-matrix treatment improved mobility of mice on a treadmill. Together, these results suggest a novel approach for regenerative myogenesis, whereby treatment only with a matrix, which possesses an inherent ability to guide myogenic differentiation of pluripotent stem cells, can enhance the endogenous vascular and myogenic regeneration of skeletal muscle, thus holding promise for future clinical use.
Skeletal muscle morphology, protein synthesis, and gene expression in Ehlers-Danlos syndrome.
Nygaard Rie H,Jensen Jakob K,Voermans Nicol C,Heinemeier Katja M,Schjerling Peter,Holm Lars,Agergaard Jakob,Mackey Abigail L,Andersen Jesper L,Remvig Lars,Kjaer Michael
Journal of applied physiology (Bethesda, Md. : 1985)
Patients with Ehlers-Danlos syndrome (EDS) are known to have genetically impaired connective tissue and skeletal muscle symptoms in form of pain, fatigue, and cramps; however earlier studies have not been able to link these symptoms to morphological muscle changes. We obtained skeletal muscle biopsies in patients with classic EDS [cEDS; = 5 (Denmark)+ 8 (The Netherlands)] and vascular EDS (vEDS; = 3) and analyzed muscle fiber morphology and content (Western blotting and muscle fiber type/area distributions) and muscle mRNA expression and protein synthesis rate (RT-PCR and stable isotope technique). The cEDS patients did not differ from healthy controls ( = 7-11) with regard to muscle fiber type/area, myosin/α-actin ratio, muscle protein synthesis rate, or mRNA expression. In contrast, the vEDS patients demonstrated higher expression of matrix proteins compared with cEDS patients (fibronectin and MMP-2). The cEDS patients had surprisingly normal muscle morphology and protein synthesis, whereas vEDS patients demonstrated higher mRNA expression for extracellular matrix remodeling in skeletal musculature compared with cEDS patients. This study is the first of its kind to systematically investigate muscle biopsies from Ehlers-Danlos patients, focusing on muscle structure and function. These patients suffer from severe muscle symptoms, but in our study they show surprisingly normal muscle findings, which points toward indirect muscle symptoms originating from the surrounding connective tissue. These findings have basal physiological importance and implications for future physiotherapeutic treatment options for these patients.
The role of extracellular matrix in retinal vascular development and preretinal neovascularization.
Bishop Paul N
Experimental eye research
Extracellular matrix (ECM) plays a central role in angiogenesis. ECM degrading enzymes breakdown the pre-existing vascular basement membrane at an early stage of angiogenesis and subsequently degrade stromal ECM as the new vessels invade into tissues. Conversely certain ECM components including collagen, fibronectin or fibrin are required for endothelial cell migration and tube morphogenesis. As the new vessels form they lay down a basement membrane that surrounds the endothelial tubes and is essential for their stability. In the rodent eye the transient expression of fibronectin and matricellular proteins plays a key role in retinal vascular development. In pathological retinal angiogenesis, such as in proliferative diabetic retinopathy, preretinal neovascularization occurs where new blood vessels invade the cortical vitreous gel and these blood vessels require vitreous collagen for their growth. The vitreous is normally anti-angiogenic and contains endogenous ECM inhibitors of angiogenesis including opticin and thombospondins, and ECM fragments such as endostatin. In preretinal neovascularization, the combined anti-angiogenic effects of these molecules are overcome by an excess of growth factors such as vascular endothelial growth factor-A, and new vessels grow into the vitreous with potentially blinding sequelae.
Basic Components of Vascular Connective Tissue and Extracellular Matrix.
Advances in pharmacology (San Diego, Calif.)
Though the composition of the three layers constituting the blood vessel wall varies among the different types of blood vessels, and some layers may even be missing in capillaries, certain basic components, and properties are shared by all blood vessels, though each histologically distinct layer contains a unique complement of extracellular components, growth factors and cytokines, and cell types as well. The structure and composition of vessel layers informs and is informed by the function of the particular blood vessel. The adaptation of the composition and the resulting function of the extracellular matrix (ECM) to changes in circulation/blood flow and a variety of other extravascular stimuli can be characterized as remodeling spearheaded by vascular cells. There is a surprising amount of cell traffic among the three layers. It starts with endothelial cell mediated transmigration of inflammatory cells from the bloodstream into the subendothelium, and then into tissue adjoining the blood vessel. Smooth muscle cells and a variety of adventitial cells reside in tunica media and tunica externa, respectively. The latter cells are a mixture of progenitor/stem cells, fibroblasts, myofibroblasts, pericytes, macrophages, and dendritic cells and respond to endothelial injury by transdifferentiation as they travel into the two inner layers, intima and media for corrective mission in the ECM composition. This chapter addresses the role of various vascular cell types and ECM components synthesized by them in maintenance of normal structure and in their contribution to major pathological processes, such as atherosclerosis, organ fibrosis, and diabetic retinopathy.
Minoxidil improves vascular compliance, restores cerebral blood flow, and alters extracellular matrix gene expression in a model of chronic vascular stiffness.
Knutsen Russell H,Beeman Scott C,Broekelmann Thomas J,Liu Delong,Tsang Kit Man,Kovacs Attila,Ye Li,Danback Joshua R,Watson Anderson,Wardlaw Amanda,Wagenseil Jessica E,Garbow Joel R,Shoykhet Michael,Kozel Beth A
American journal of physiology. Heart and circulatory physiology
Increased vascular stiffness correlates with a higher risk of cardiovascular complications in aging adults. Elastin (ELN) insufficiency, as observed in patients with Williams-Beuren syndrome or with familial supravalvular aortic stenosis, also increases vascular stiffness and leads to arterial narrowing. We used Eln mice to test the hypothesis that pathologically increased vascular stiffness with concomitant arterial narrowing leads to decreased blood flow to end organs such as the brain. We also hypothesized that drugs that remodel arteries and increase lumen diameter would improve flow. To test these hypotheses, we compared carotid blood flow using ultrasound and cerebral blood flow using MRI-based arterial spin labeling in wild-type (WT) and Eln mice. We then studied how minoxidil, an ATP-sensitive K channel opener and vasodilator, affects vessel mechanics, blood flow, and gene expression. Both carotid and cerebral blood flows were lower in Eln mice than in WT mice. Treatment of Eln mice with minoxidil lowered blood pressure and reduced functional arterial stiffness to WT levels. Minoxidil also improved arterial diameter and restored carotid and cerebral blood flows in Eln mice. The beneficial effects persisted for weeks after drug removal. RNA-Seq analysis revealed differential expression of 127 extracellular matrix-related genes among the treatment groups. These results indicate that ELN insufficiency impairs end-organ perfusion, which may contribute to the increased cardiovascular risk. Minoxidil, despite lowering blood pressure, improves end-organ perfusion. Changes in matrix gene expression and persistence of treatment effects after drug withdrawal suggest arterial remodeling. Such remodeling may benefit patients with genetic or age-dependent ELN insufficiency. NEW & NOTEWORTHY Our work with a model of chronic vascular stiffness, the elastin ( Eln) mouse, shows reduced brain perfusion as measured by carotid ultrasound and MRI arterial spin labeling. Vessel caliber, functional stiffness, and blood flow improved with minoxidil. The ATP-sensitive K channel opener increased Eln gene expression and altered 126 other matrix-associated genes.
The extracellular matrix of blood vessels.
Eble Johannes A,Niland Stephan
Current pharmaceutical design
Blood vessels are highly organized and complex structure, which are far more than simple tubes conducting the blood to almost any tissue of the body. They are able to autonomously regulate the blood flow, thus providing the tissues an optimal support of oxygen and nutrients and an efficient removal of waste products. In higher organisms, the blood vessel forms a closed circuit system, which additionally has the ability to seal itself in case of leakage as a result of injury. The blood vessel system does not only transport soluble substances, but also serves as "highway" system for leukocytes to patrol the body during the immunological surveillance and to reach the inflammation site quickly. In a complex interplay with the vascular wall, leukocytes are able to penetrate the blood vessel without any obvious leakage. Pathologically, tumor cells subvert the blood vessel system to disseminate from the primary tumor and colonize distant organs during metastasis. The extracellular matrix (ECM) of a blood vessel contributes substantially to the diverse functions of the blood vessel. First, the ECM constitutes the scaffold which keeps the histological structure of the vessel wall in shape but also bears the enormous and permanent mechanical forces levied on the vessel by the pulsatile blood flow in the arteries and by vasoconstriction, which regulates blood flow and pressure. The complex network of elastic fibers and tensile forces-bearing networks are well adapted to accomplish these mechanical tasks. Second, the ECM provides informational cues to the vascular cells, thus regulating their proliferation and differentiation. Third, ECM molecules can store, mask, present or sequester growth factors, thereby modulating their effects remarkably. Furthermore, several ECM molecules serve additional functions within the blood vessel. Their expression is altered in a spatial and temporal pattern during blood vessel formation and remodeling. In contrast to vasculogenesis during embryonic development, blood vessel shows a remarkably and life-long plasticity, which allows the formation and regeneration of new blood vessel even in adulthood. Both physiologically during wound healing and pathologically during tumor growth, the sprouting of new blood vessels during angiogenesis is an important process, in which the ECM takes a key role.
Smooth muscle-specific TMEM16A expression protects against angiotensin II-induced cerebrovascular remodeling via suppressing extracellular matrix deposition.
Zeng Xue-Lin,Sun Lu,Zheng Hua-Qing,Wang Guan-Lei,Du Yan-Hua,Lv Xiao-Fei,Ma Ming-Ming,Guan Yong-Yuan
Journal of molecular and cellular cardiology
Cerebrovascular remodeling is the leading factor for stroke and characterized by increased extracellular matrix deposition, migration and proliferation of vascular smooth muscle cells, and inhibition of their apoptosis. TMEM16A is an important component of Ca-activated Cl channels. Previously, we showed that downregulation of TMEM16A in the basilar artery was negatively correlated with cerebrovascular remodeling during hypertension. However, it is unclear whether TMEM16A participates in angiotensin II (Ang II)-induced vascular remodeling in mice that have TMEM16A gene modification. In this study, we generated a transgenic mouse that overexpresses TMEM16A specifically in vascular smooth muscle cells. We observed that vascular remodeling in the basilar artery during Ang II-induced hypertension was significantly suppressed upon vascular smooth muscle-specific overexpression of TMEM16A relative to control mice. Specifically, we observed a large reduction in the deposition of fibronectin and collagen I. The expression of matrix metalloproteinases (MMP-2, MMP-9, and MMP-14), and tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) were upregulated in the basilar artery during Ang II-induced hypertension, but this was suppressed upon overexpression of TMEM16A in blood vessels. Furthermore, TMEM16A overexpression alleviated the overactivity of the canonical TGF-β1/Smad3, and non-canonical TGF-β1/ERK and JNK pathways in the basilar artery during Ang II-induced hypertension. These in vivo results were similar to the results derived in vitro with basilar artery smooth muscle cells stimulated by Ang II. Moreover, we observed that the inhibitory effect of TMEM16A on MMPs was mediated by decreasing the activation of WNK1, which is a Cl-sensitive serine/threonine kinase. In conclusion, this study demonstrates that TMEM16A protects against cerebrovascular remodeling during hypertension by suppressing extracellular matrix deposition. We also showed that TMEM16A exerts this effect by reducing the expression of MMPs via inhibiting WNK1, and decreasing the subsequent activities of TGF-β1/Smad3, ERK, and JNK. Accordingly, our results suggest that TMEM16A may serve as a novel therapeutic target for vascular remodeling.
Extracellular matrix inflammation in vascular cognitive impairment and dementia.
Rosenberg Gary A
Clinical science (London, England : 1979)
Vascular cognitive impairment and dementia (VCID) include a wide spectrum of chronic manifestations of vascular disease related to large vessel strokes and small vessel disease (SVD). Lacunar strokes and white matter (WM) injury are consequences of SVD. The main vascular risk factor for SVD is brain hypoperfusion from cerebral blood vessel narrowing due to chronic hypertension. The hypoperfusion leads to activation and degeneration of astrocytes with the resulting fibrosis of the extracellular matrix (ECM). Elasticity is lost in fibrotic cerebral vessels, reducing the response of stiffened blood vessels in times of increased metabolic need. Intermittent hypoxia/ischaemia activates a molecular injury cascade, producing an incomplete infarction that is most damaging to the deep WM, which is a watershed region for cerebral blood flow. Neuroinflammation caused by hypoxia activates microglia/macrophages to release proteases and free radicals that perpetuate the damage over time to molecules in the ECM and the neurovascular unit (NVU). Matrix metalloproteinases (MMPs) secreted in an attempt to remodel the blood vessel wall have the undesired consequences of opening the blood-brain barrier (BBB) and attacking myelinated fibres. This dual effect of the MMPs causes vasogenic oedema in WM and vascular demyelination, which are the hallmarks of the subcortical ischaemic vascular disease (SIVD), which is the SVD form of VCID also called Binswanger's disease (BD). Unravelling the complex pathophysiology of the WM injury-related inflammation in the small vessel form of VCID could lead to novel therapeutic strategies to reduce damage to the ECM, preventing the progressive damage to the WM.
A hydrogel derived from acellular blood vessel extracellular matrix to promote angiogenesis.
Fu Wei,Xu Peng,Feng Bei,Lu Yang,Bai Jie,Zhang Jialiang,Zhang Wenjie,Yin Meng
Journal of biomaterials applications
The biocompatibility and bioactivity of injectable acellular extracellular matrix nominates its use as an optimal candidate for cell delivery, serving as a reconstructive scaffold. In this study, we investigated the feasibility of preparing a blood vessel matrix (BVM) hydrogel, which revealed its pro-angiogenic effects in vitro and its therapeutic effects in an in vivo skin flap model. Aortic and abdominal aortic arteries from pigs were acellularized by Triton-X 100 and confirmed by hematoxylin and eosin and 4,6-diamidino-2-phenylindole staining. Different concentrations of blood vessel matrix hydrogel were generated successfully through enzymatic digestion, neutralization, and gelation. Hematoxylin and eosin staining, Masson's trichrome staining, collagen type I immunohistochemistry staining, and enzyme-linked immunosorbent assays showed that type I collagen and some growth factors were retained in the hydrogel. Scanning electron microscopy demonstrated the different diametric fibrils in blood vessel matrix hydrogels. A blood vessel matrix hydrogel-coated plate promoted the tube formation of human umbilical vein endothelial cells in vitro. After injection into skin flaps, the hydrogel improved the flap survival rate and increased blood perfusion and capillary density. These results indicated that we successfully prepared a blood vessel matrix hydrogel and demonstrated its general characteristics and angiogenic effects in vitro and in vivo.
Microstructured human fibroblast-derived extracellular matrix scaffold for vascular media fabrication.
Bourget Jean-Michel,Laterreur Véronique,Gauvin Robert,Guillemette Maxime D,Miville-Godin Caroline,Mounier Maxence,Tondreau Maxime Y,Tremblay Catherine,Labbé Raymond,Ruel Jean,Auger François A,Veres Teodor,Germain Lucie
Journal of tissue engineering and regenerative medicine
In the clinical and pharmacological fields, there is a need for the production of tissue-engineered small-diameter blood vessels. We have demonstrated previously that the extracellular matrix (ECM) produced by fibroblasts can be used as a scaffold to support three-dimensional (3D) growth of another cell type. Thus, a resistant tissue-engineered vascular media can be produced when such scaffolds are used to culture smooth muscle cells (SMCs). The present study was designed to develop an anisotropic fibroblastic ECM sheet that could replicate the physiological architecture of blood vessels after being assembled into a small diameter vascular conduit. Anisotropic ECM scaffolds were produced using human dermal fibroblasts, grown on a microfabricated substrate with a specific topography, which led to cell alignment and unidirectional ECM assembly. Following their devitalization, the scaffolds were seeded with SMCs. These cells elongated and migrated in a single direction, following a specific angle relative to the direction of the aligned fibroblastic ECM. Their resultant ECM stained for collagen I and III and elastin, and the cells expressed SMC differentiation markers. Seven days after SMCs seeding, the sheets were rolled around a mandrel to form a tissue-engineered vascular media. The resulting anisotropic ECM and cell alignment induced an increase in the mechanical strength and vascular reactivity in the circumferential direction as compared to unaligned constructs. Copyright © 2016 John Wiley & Sons, Ltd.
Extracellular matrix scaffolding in angiogenesis and capillary homeostasis.
Marchand Marion,Monnot Catherine,Muller Laurent,Germain Stéphane
Seminars in cell & developmental biology
The extracellular matrix (ECM) of blood vessels, which is composed of both the vascular basement membrane (BM) and the interstitial ECM is identified as a crucial component of the vasculature. We here focus on the unique molecular composition and scaffolding of the capillary ECM, which provides structural support to blood vessels and regulates properties of endothelial cells and pericytes. The major components of the BM are collagen IV, laminins, heparan sulfate proteoglycans and nidogen and also associated proteins such as collagen XVIII and fibronectin. Their organization and scaffolding in the BM is required for proper capillary morphogenesis and maintenance of vascular homeostasis. The BM also regulates vascular mechanosensing. A better understanding of the mechanical and structural properties of the vascular BM and interstitial ECM therefore opens new perspectives to control physiological and pathological angiogenesis and vascular homeostasis. The overall aim of this review is to explain how ECM scaffolding influences angiogenesis and capillary integrity.
Transplantation of three-dimensional artificial human vascular tissues fabricated using an extracellular matrix nanofilm-based cell-accumulation technique.
Asano Yoshiya,Shimoda Hiroshi,Okano Daisuke,Matsusaki Michiya,Akashi Mitsuru
Journal of tissue engineering and regenerative medicine
We have established a novel three-dimensional (3D) tissue-constructing technique, referred to as the 'cell-accumulation method', which is based on the self-assembly of cultured human cells. In this technique, cells are coated with fibronectin and gelatin to construct extracellular matrix (ECM) nanofilms and cultured to form multi-layers in vitro. By using this method, we have successfully fabricated artificial tissues with vascular networks constructed by co-cultivation of human umbilical vein-derived vascular endothelial cells between multi-layers of normal human dermal fibroblasts. In this study, to assess these engineered vascular tissues as therapeutic implants, we transplanted the 3D human tissues with microvascular networks, fabricated based on the cell-accumulation method, onto the back skin of nude mice. After the transplantation, we found vascular networks with perfusion of blood in the transplanted graft. At the boundary between host and implanted tissue, connectivity between murine and human vessels was found. Transmission electron microscopy of the implanted artificial vascular tubules demonstrated the ultrastructural features of blood capillaries. Moreover, maturation of the vascular tissues after transplantation was shown by the presence of pericyte-like cells and abundant collagen fibrils in the ECM surrounding the vasculature. These results demonstrated that artificial human vascular tissues constructed by our method were engrafted and matured in animal skin. In addition, the implanted artificial human vascular networks were connected with the host circulatory system by anastomosis. This method is an attractive technique for engineering prevascularized artificial tissues for transplantation. Copyright © 2015 John Wiley & Sons, Ltd.
NOX1 Negatively Modulates Fibulin-5 in Vascular Smooth Muscle Cells to Affect Aortic Dissection.
Hu Xiaoping,Jiang Wanli,Wang Zhiwei,Li Luocheng,Hu Zhipeng
Biological & pharmaceutical bulletin
Aortic dissection (AD) diseases are characterized by degeneration of the aortic media. Oxidative stress plays a crucial role in the development of AD. Reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 (NOX1) deficiency reduces the incidence of aortic dissection induced by angiotensin II, but its mechanism remains to be further elucidated. The expression of Fibulin-5 is decreased in patients with AD, but its upstream mechanism is still unclear. This study was to clarify the relationship between NOX1 and Fibulin-5 in the AD. Results showed that the expressions of NOX1 and Fibulin-5 were increased and decreased in the AD, respectively. Next, by employing gain- and loss-of-function approaches in vitro, NOX1 negatively regulated Fibulin-5 in the vascular smooth muscle cells. Moreover, the blunted activity of NOX1 with VAS2870 could upregulate the expression of Fibulin-5. These findings indicate NOX1 is a negative modulator of Fibulin-5 in the AD.
Perivascular Adipose Tissue Regulates Vascular Function by Targeting Vascular Smooth Muscle Cells.
Chang Lin,Garcia-Barrio Minerva T,Chen Y Eugene
Arteriosclerosis, thrombosis, and vascular biology
Adipose tissues are present at multiple locations in the body. Most blood vessels are surrounded with adipose tissue which is referred to as perivascular adipose tissue (PVAT). Similarly to adipose tissues at other locations, PVAT harbors many types of cells which produce and secrete adipokines and other undetermined factors which locally modulate PVAT metabolism and vascular function. Uncoupling protein-1, which is considered as a brown fat marker, is also expressed in PVAT of rodents and humans. Thus, compared with other adipose tissues in the visceral area, PVAT displays brown-like characteristics. PVAT shows a distinct function in the cardiovascular system compared with adipose tissues in other depots which are not adjacent to the vascular tree. Growing and extensive studies have demonstrated that presence of normal PVAT is required to maintain the vasculature in a functional status. However, excessive accumulation of dysfunctional PVAT leads to vascular disorders, partially through alteration of its secretome which, in turn, affects vascular smooth muscle cells and endothelial cells. In this review, we highlight the cross talk between PVAT and vascular smooth muscle cells and its roles in vascular remodeling and blood pressure regulation.
Downregulation of HDAC1 suppresses media degeneration by inhibiting the migration and phenotypic switch of aortic vascular smooth muscle cells in aortic dissection.
Sun Lin,Wang Chunping,Yuan Ye,Guo Zhen,He Yubin,Ma Wenrui,Zhang Jing
Journal of cellular physiology
Although much progress has been made in the diagnosis and treatment of thoracic aortic dissection (TAD), the overall morbidity and mortality rates of TAD are still high. Therefore, the molecular pathogenesis and etiology of TAD need to be elucidated. In this study, we found that histone deacetylase 1 (HDAC1) expression is dramatically higher in the aortic wall of patients with TAD (than that in a normal group) and negatively correlates with the levels of the vascular smooth muscle cell (SMC) contractile-phenotype markers. Knockdown of HDAC1 upregulated both smooth muscle 22 α (SM22α) and α-smooth muscle actin (α-SMA) in platelet-derived growth factor (PDGF)-BB-treated and -untreated SMCs. In addition, the knockdown of HDAC1 markedly decreased SMC viability and migration in contrast to the control group under the conditions of quiescence and PDGF-BB treatment. We also showed that the expression of polycystic kidney disease 1 (PKD1) is decreased in the aortic wall of patients with TAD and negatively correlates with HDAC1 expression. Overexpressed PKD1 obviously increased SM22α and α-SMA expression and reduced the viability and migration of SMCs, but these effects were attenuated by HDAC1. Furthermore, we demonstrated that HDAC1 serves as an important modulator of the migration and phenotypic switch of SMCs by suppressing the PKD1- mammalian target of the rapamycin signaling pathway. HDAC1 downregulation inhibited media degeneration and attenuated the loss of elastic-fiber integrity in a mouse model of TAD. Our results suggest that HDAC1 might be a new target for the treatment of a macrovascular disease such as TAD.
Miconazole protects blood vessels from MMP9-dependent rupture and hemorrhage.
Yang Ran,Zhang Yunpei,Huang Dandan,Luo Xiao,Zhang Liangren,Zhu Xiaojun,Zhang Xiaolin,Liu Zhenming,Han Jing-Yan,Xiong Jing-Wei
Disease models & mechanisms
Hemorrhagic stroke accounts for 10-15% of all strokes and is strongly associated with mortality and morbidity worldwide, but its prevention and therapeutic interventions remain a major challenge. Here, we report the identification of miconazole as a hemorrhagic suppressor by a small-molecule screen in zebrafish. We found that a hypomorphic mutant , one of several known mutant alleles in zebrafish, had the major symptoms of brain hemorrhage, vessel rupture and inflammation as those in hemorrhagic stroke patients. A small-molecule screen with mutant embryos identified the anti-fungal drug miconazole as a potent hemorrhagic suppressor. Miconazole inhibited both brain hemorrhages in zebrafish and mesenteric hemorrhages in rats by decreasing matrix metalloproteinase 9 (MMP9)-dependent vessel rupture. Mechanistically, miconazole downregulated the levels of pErk and Mmp9 to protect vascular integrity in mutants. Therefore, our findings demonstrate that miconazole protects blood vessels from hemorrhages by downregulating the pERK-MMP9 axis from zebrafish to mammals and shed light on the potential of phenotype-based screens in zebrafish for the discovery of new drug candidates and chemical probes for hemorrhagic stroke.
Smooth Muscle Peroxisome Proliferator-Activated Receptor γ Plays a Critical Role in Formation and Rupture of Cerebral Aneurysms in Mice In Vivo.
Hasan David M,Starke Robert M,Gu He,Wilson Katina,Chu Yi,Chalouhi Nohra,Heistad Donald D,Faraci Frank M,Sigmund Curt D
Hypertension (Dallas, Tex. : 1979)
Vascular inflammation plays a critical role in the pathogenesis of cerebral aneurysms. Peroxisome proliferator-activated receptor γ (PPARγ) protects against vascular inflammation and atherosclerosis, whereas dominant-negative mutations in PPARγ promote atherosclerosis and vascular dysfunction. We tested the role of PPARγ in aneurysm formation and rupture. Aneurysms were induced with a combination of systemic infusion of angiotensin-II and local injection of elastase in (1) mice that received the PPARγ antagonist GW9662 or the PPARγ agonist pioglitazone, (2) mice carrying dominant-negative PPARγ mutations in endothelial or smooth muscle cells, and (3) mice that received the Cullin inhibitor MLN4924. Incidence of aneurysm formation, rupture, and mortality was quantified. Cerebral arteries were analyzed for expression of Cullin3, Kelch-like ECH-associated protein 1, nuclear factor (erythroid-derived 2)-like 2, NAD(P)H dehydrogenase (quinone)1 (NQO1), and inflammatory marker mRNAs. Neither pioglitazone nor GW9662 altered the incidence of aneurysm formation. GW9662 significantly increased the incidence of aneurysm rupture, whereas pioglitazone tended to decrease the incidence of rupture. Dominant-negative endothelial-specific PPARγ did not alter the incidence of aneurysm formation or rupture. In contrast, dominant-negative smooth muscle-specific PPARγ resulted in an increase in aneurysm formation (P<0.05) and rupture (P=0.05). Dominant-negative smooth muscle-specific PPARγ, but not dominant-negative endothelial-specific PPARγ, resulted in significant decreases in expression of genes encoding Cullin3, Kelch-like ECH-associated protein 1, and nuclear factor (erythroid-derived 2)-like 2, along with significant increases in tumor necrosis factor-α, monocyte chemoattractant protein-1, chemokine (C-X-C motif) ligand 1, CD68, matrix metalloproteinase-3, -9, and -13. MLN4924 did not alter incidence of aneurysm formation, but increased the incidence of rupture (P<0.05). In summary, endogenous PPARγ, specifically smooth muscle PPARγ, plays an important role in protecting from formation and rupture of experimental cerebral aneurysms in mice.
TNF-α induces phenotypic modulation in cerebral vascular smooth muscle cells: implications for cerebral aneurysm pathology.
Ali Muhammad S,Starke Robert M,Jabbour Pascal M,Tjoumakaris Stavropoula I,Gonzalez L Fernando,Rosenwasser Robert H,Owens Gary K,Koch Walter J,Greig Nigel H,Dumont Aaron S
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
Little is known about vascular smooth muscle cell (SMC) phenotypic modulation in the cerebral circulation or pathogenesis of intracranial aneurysms. Tumor necrosis factor-alpha (TNF-α) has been associated with aneurysms, but potential mechanisms are unclear. Cultured rat cerebral SMCs overexpressing myocardin induced expression of key SMC contractile genes (SM-α-actin, SM-22α, smooth muscle myosin heavy chain), while dominant-negative cells suppressed expression. Tumor necrosis factor-alpha treatment inhibited this contractile phenotype and induced pro-inflammatory/matrix-remodeling genes (monocyte chemoattractant protein-1, matrix metalloproteinase-3, matrix metalloproteinase-9, vascular cell adhesion molecule-1, interleukin-1 beta). Tumor necrosis factor-alpha increased expression of KLF4, a known regulator of SMC differentiation. Kruppel-like transcription factor 4 (KLF4) small interfering RNA abrogated TNF-α activation of inflammatory genes and suppression of contractile genes. These mechanisms were confirmed in vivo after exposure of rat carotid arteries to TNF-α and early on in a model of cerebral aneurysm formation. Treatment with the synthesized TNF-α inhibitor 3,6-dithiothalidomide reversed pathologic vessel wall alterations after induced hypertension and hemodynamic stress. Chromatin immunoprecipitation assays in vivo and in vitro demonstrated that TNF-α promotes epigenetic changes through KLF4-dependent alterations in promoter regions of myocardin, SMCs, and inflammatory genes. In conclusion, TNF-α induces phenotypic modulation of cerebral SMCs through myocardin and KLF4-regulated pathways. These results demonstrate a novel role for TNF-α in promoting a pro-inflammatory/matrix-remodeling phenotype, which has important implications for the mechanisms behind intracranial aneurysm formation.
Vascular smooth muscle cell death, autophagy and senescence in atherosclerosis.
Grootaert Mandy O J,Moulis Manon,Roth Lynn,Martinet Wim,Vindis Cécile,Bennett Martin R,De Meyer Guido R Y
In the present review, we describe the causes and consequences of loss of vascular smooth muscle cells (VSMCs) or their function in advanced atherosclerotic plaques and discuss possible mechanisms such as cell death or senescence, and induction of autophagy to promote cell survival. We also highlight the potential use of pharmacological modulators of these processes to limit plaque progression and/or improve plaque stability. VSMCs play a pivotal role in atherogenesis. Loss of VSMCs via initiation of cell death leads to fibrous cap thinning and promotes necrotic core formation and calcification. VSMC apoptosis is induced by pro-inflammatory cytokines, oxidized low density lipoprotein, high levels of nitric oxide and mechanical injury. Apoptotic VSMCs are characterized by a thickened basal lamina surrounding the cytoplasmic remnants of the VSMC. Inefficient clearance of apoptotic VSMCs results in secondary necrosis and subsequent inflammation. A critical determinant in the VSMC stress response and phenotypic switching is autophagy, which is activated by various stimuli, including reactive oxygen and lipid species, cytokines, growth factors and metabolic stress. Successful autophagy stimulates VSMC survival, whereas reduced autophagy promotes age-related changes in the vasculature. Recently, an interesting link between autophagy and VSMC senescence has been uncovered. Defective VSMC autophagy accelerates not only the development of stress-induced premature senescence but also atherogenesis, albeit without worsening plaque stability. VSMC senescence in atherosclerosis is likely a result of replicative senescence and/or stress-induced premature senescence in response to DNA damaging and/or oxidative stress-inducing stimuli. The finding that VSMC senescence can promote atherosclerosis further illustrates that normal, adequate VSMC function is crucial in protecting the vessel wall against atherosclerosis.
DFMG reverses proliferation and migration of vascular smooth muscle cells induced by co-culture with injured vascular endothelial cells via suppression of the TLR4-mediated signaling pathway.
Cong Li,Zhang Yong,Huang He,Cao Jianguo,Fu Xiaohua
Molecular medicine reports
7-Difluoromethoxy-5,4'-dimethoxy-genistein (DFMG) is a novel chemical compound synthesized using genistein. Previous studies have indicated that DFMG can reverse the apoptosis of vascular endothelial cells (VECs) by regulating the mitochondrial apoptosis pathway. The present study aimed to investigate the activity and molecular mechanism underlying DFMG‑mediated protection of vascular smooth muscle cell (VSMCs) using a non‑contact co‑culture model established by using Transwell insert. Secretion of interleukin‑6 (IL‑6) and tumor necrosis factor‑α (TNF‑α) were measured by ELISA. Proliferation and migration of VSMCs were assessed using a Cell Counting kit‑8 and wound healing assays, respectively. Toll‑like receptor 4 (TLR4) mRNA and protein levels were detected by reverse transcription-quantitative polymerase chain reaction and western blotting analyses, respectively. In the present study, lysophosphatidylcholine (LPC) significantly increased the secretion of IL‑6 and TNF‑α in VECs. VECs treated with LPC markedly increased proliferation and migration of VSMCs, which were inhibited by DFMG. Transfection of either TLR4 short hairpin RNA (shRNA) or TLR4 cDNA in VECs inhibited and increased proliferation and migration of VSMCs, respectively. Furthermore, transfection of VECs with TLR4 shRNA suppressed the proliferation and migration of VSMCs induced by co‑culture with injured VECs, which was further enhanced by treatment with DFMG. By contrast, transfection of VECs with TLR4 cDNA enhanced proliferation and migration of VSMCs and this effect was inhibited by treatment with DFMG. Taken together, the results of the present study demonstrated that DFMG can reverse proliferation and migration of VSMCs induced by co‑culture with injured VECs via suppression of the TLR4‑mediated signaling pathway.
LncRNA HCG11 regulates proliferation and apoptosis of vascular smooth muscle cell through targeting miR-144-3p/FOXF1 axis in atherosclerosis.
Liu Yi,Cui Xiyun,Wang Cong,Zhao Sihai
BACKGROUND:Atherosclerosis (AS) is the main pathological basis of coronary heart disease, cerebral infarction and peripheral vascular disease, which seriously endanger people's life and health. In recent years, long non-coding RNA (lncRNA) has been found to be involved in gene expression regulation, but the research on AS is still in the initial stage. In this study, we mainly studied the role of HCG11 in patients with AS. Quantitative Real-time Polymerase Chain Reaction (QRT-PCR) was used to detect the expression of HCG11 and miR-144 in the serum of AS patients and healthy volunteers. Oxidation Low Lipoprotein (Ox-LDL), interleukin-6 (IL-6) and tumor necrosis factor α (TNF α) radiation were used to establish human vascular smooth muscle cells (VSMCs) in vitro model. Cell proliferation was determined by Cell Counting Kit-8 (CCK-8) assay. The apoptosis rate was determined by flow cytometry (FACS) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) staining. The expression levels of Forkhead box protein F1 (FOXF1), B cell lymphoma-2 (Bcl-2) and BCL2-Associated X (Bax) were detected by qRT-PCR. Luciferase gene reporter and RNA pull down experiments confirmed the relationship between HCG11 and miR-144, miR-144 and FOXF1. RESULTS:This study showed that HCG11 was significantly upregulated in patients with AS, while miR-144 was down-regulated in patients with AS. Ox-LDL and IL-6 in VSMCs induced up-regulation of HCG11 and down-regulation of miR-144. Overexpression of HCG11 promoted the proliferation and inhibited apoptosis of VSMCs. Luciferase gene reporter gene assay showed that HCG11 could bind to miR-144, and miR-144 could bind to FOXF1. Overexpression of miR-144 reversed the effect of HCG11 on VSMCs. CONCLUSIONS:LncRNA HCG11 regulates proliferation and apoptosis of vascular smooth muscle cell through targeting miR-144-3p/FOXF1 axis.
Lactate Promotes Synthetic Phenotype in Vascular Smooth Muscle Cells.
Yang Libang,Gao Ling,Nickel Thomas,Yang Jing,Zhou Jingyi,Gilbertsen Adam,Geng Zhaohui,Johnson Caitlin,Young Bernice,Henke Craig,Gourley Glenn R,Zhang Jianyi
RATIONALE:The phenotypes of vascular smooth muscle cells (vSMCs) comprise a continuum bounded by predominantly contractile and synthetic cells. Some evidence suggests that contractile vSMCs can assume a more synthetic phenotype in response to ischemic injury, but the mechanisms that activate this phenotypic switch are poorly understood. OBJECTIVE:To determine whether lactate, which increases in response to regional ischemia, may promote the synthetic phenotype in vSMCs. METHODS AND RESULTS:Experiments were performed with vSMCs that had been differentiated from human induced pluripotent stem cells and then cultured in glucose-free, lactate-enriched (L) medium or in standard (L) medium. Compared with the L medium, the L medium was associated with significant increases in synthetic vSMC marker expression, proliferation, and migration and with significant declines in contractile and apoptotic activity. Furthermore, these changes were accompanied by increases in the expression of monocarboxylic acid transporters and were generally attenuated both by the blockade of monocarboxylic acid transporter activity and by transfection with iRNA for (). Proteomics, biomarker, and pathway analyses suggested that the L medium tended to upregulate the expression of synthetic vSMC markers, the production of extracellular proteins that participate in tissue construction or repair, and the activity of pathways that regulate cell proliferation and migration. Observations in hypoxia-cultured vSMCs were similar to those in L-cultured vSMCs, and assessments in a swine myocardial infarction model suggested that measurements of lactate levels, lactate-dehydrogenase levels, vSMC proliferation, and monocarboxylic acid transporter and NDRG expression were greater in the ischemic zone than in nonischemic tissues. CONCLUSIONS:These results demonstrate for the first time that vSMCs assume a more synthetic phenotype in a microenvironment that is rich in lactate. Thus, mechanisms that link glucose metabolism to vSMC phenotypic switching could play a role in the pathogenesis and treatment of cardiovascular disease.
Diethyl citrate and sodium citrate reduce the cytotoxic effects of nanosized hydroxyapatite crystals on mouse vascular smooth muscle cells.
Zhang Chong-Yu,Sun Xin-Yuan,Ouyang Jian-Ming,Gui Bao-Song
International journal of nanomedicine
Objective:This study aimed to investigate the damage mechanism of nanosized hydroxyapatite (nano-HAp) on mouse aortic smooth muscle cells (MOVASs) and the injury-inhibiting effects of diethyl citrate (EtCit) and sodium citrate (NaCit) to develop new drugs that can simultaneously induce anticoagulation and inhibit vascular calcification. Methods:The change in cell viability was evaluated using a cell proliferation assay kit, and the amount of lactate dehydrogenase (LDH) released was measured using an LDH kit. Intracellular reactive oxygen species (ROS) and mitochondrial damage were detected by DCFH-DA staining and JC-1 staining. Cell apoptosis and necrosis were detected by Annexin V staining. Intracellular calcium concentration and lysosomal integrity were measured using Fluo-4/AM and acridine orange, respectively. Results:Nano-HAp decreased cell viability and damaged the cell membrane, resulting in the release of a large amount of LDH. Nano-HAp entered the cells and damaged the mitochondria, and then induced cell apoptosis by producing a large amount of ROS. In addition, nano-HAp increased the intracellular Ca concentration, leading to lysosomal rupture and cell necrosis. On addition of the anticoagulant EtCit or NaCit, cell viability and mitochondrial membrane potential increased, whereas the amount of LDH released, ROS, and apoptosis rate decreased. Et Cit and NaCit could also chelate with Ca to inhibit the intracellular Ca elevations induced by nano-HAp, prevent lysosomal rupture, and reduce cell necrosis. High concentrations of EtCit and NaCit exhibited strong inhibitory effects. The inhibitory capacity of NaCit was stronger than that of EtCit at similar concentrations. Conclusion:Both EtCit and NaCit significantly reduced the cytotoxicity of nano-HAp on MOVASs and inhibited the apoptosis and necrosis induced by nano-HAp crystals. The chelating function of citrate resulted in both anticoagulation and binding to HAp. EtCit and NaCit may play a role as anticoagulants in reducing injury to the vascular wall caused by nano-HAp.
FOXO3a (Forkhead Transcription Factor O Subfamily Member 3a) Links Vascular Smooth Muscle Cell Apoptosis, Matrix Breakdown, Atherosclerosis, and Vascular Remodeling Through a Novel Pathway Involving MMP13 (Matrix Metalloproteinase 13).
Yu Haixiang,Fellows Adam,Foote Kirsty,Yang Zhaoqing,Figg Nichola,Littlewood Trevor,Bennett Martin
Arteriosclerosis, thrombosis, and vascular biology
OBJECTIVE:Vascular smooth muscle cell (VSMC) apoptosis accelerates atherosclerosis and promotes breakdown of the extracellular matrix, but the mechanistic links between these 2 processes are unknown. The forkhead protein FOXO3a (forkhead transcription factor O subfamily member 3a) is activated in human atherosclerosis and induces a range of proapoptotic and other transcriptional targets. We, therefore, determined the mechanisms and consequences of FOXO3a activation in atherosclerosis and arterial remodeling after injury. APPROACH AND RESULTS:Expression of a conditional FOXO3a allele (FOXO3aA3ER) potently induced VSMC apoptosis, expression and activation of MMP13 (matrix metalloproteinase 13), and downregulation of endogenous TIMPs (tissue inhibitors of MMPs). and were direct FOXO3a transcriptional targets in VSMCs. Activation of endogenous FOXO3a also induced MMP13, extracellular matrix degradation, and apoptosis, and MMP13-specific inhibitors and fibronectin reduced FOXO3a-mediated apoptosis. FOXO3a activation in mice with VSMC-restricted FOXO3aA3ER induced MMP13 expression and activity and medial VSMC apoptosis. FOXO3a activation in FOXO3aA3ER/ApoE (apolipoprotein E deficient) mice increased atherosclerosis, increased necrotic core and reduced fibrous cap areas, and induced features of medial degeneration. After carotid artery ligation, FOXO3a activation increased VSMC apoptosis, VSMC proliferation, and neointima formation, all of which were reduced by MMP13 inhibition. CONCLUSIONS:FOXO3a activation induces VSMC apoptosis and extracellular matrix breakdown, in part, because of transcriptional activation of MMP13. FOXO3a activation promotes atherosclerosis and medial degeneration and increases neointima after injury that is partly dependent on MMP13. FOXO3a-induced MMP activation represents a direct mechanistic link between VSMC apoptosis and matrix breakdown in vascular disease.
The deregulation of STIM1 and store operative calcium entry impaired aortic smooth muscle cells contractility in aortic medial degeneration.
Hong Junmou,Hu Zhipeng,Wu Qi,Tang Chaoliang,Hu Junxia,Chen Ruoshi,Li Bowen,Wang Zhiwei
Microarray analysis of clinical aortic samples suggested a potential role for stromal interaction molecule 1 (STIM1) in the modulation of aortic medial degeneration (AMD), despite the uncertainty about STIM1 in normal aortic smooth muscle cells (ASMCs). Here, we aimed to explore changes in STIM1 expression in AMD, and the possible mechanisms. An AMD model was established using auto-delivery of angiotensin II (Ang II) into ApoE mice. We assessed the effects of SKF96365, a STIM1 inhibitor, in AMD model and cultured ASMCs. Elastic van Gieson (EVG) staining was used to visualize elastic fiber injury. Mitochondria changes were viewed by TEM. Cytoplasmic calcium was quantified by measuring fluo-4 staining in a flow cytometer. Mechanical stretching device was used to mimic stretching that ASMCs experience Cell apoptosis was determined by using Annexin V/propidium iodide (PI) staining. The expression of STIM1, contractile related proteins (α-smooth muscle actin (α-SMA), myosin light chain (MLC)), endoplasmic reticulum (ER) stress-related proteins (CHOP, activating transcription factor 6 (ATF-6)) and smad2/3 were assessed by Western blotting, immunohistochemistry (IHC), and immunofluorescence (IF). SKF96365 exacerbated aortic injury in the AMD model. SKF96365 reduced cytoplasmic calcium concentration in ASMCs, caused mitochondrial swelling, and elevated the expression of ATF-6 and CHOP. SKF96365 decreased the expression of MLC and α-SMA in ASMCs, causing them to be vulnerable to mechanical stretch. SKF96365 suppressed smad2/3 activation after treatment with transforming growth factor (TGF) β1 (TGFβ1). STIM1 is indispensable in ASMCs. Interfering with STIM1 exaggerated the AMD process by modulating the expression of contractile proteins, inducing ER stress in ASMCs.
Smooth muscle cell and arterial aging: basic and clinical aspects.
Lacolley Patrick,Regnault Veronique,Avolio Alberto P
Arterial aging engages a plethora of key signalling pathways that act in concert to induce vascular smooth muscle cell (VSMC) phenotypic changes leading to vascular degeneration and extracellular matrix degradation responsible for alterations of the mechanical properties of the vascular wall. This review highlights proof-of-concept examples of components of the extracellular matrix, VSMC receptors which connect extracellular and intracellular structures, and signalling pathways regulating changes in mechanotransduction and vascular homeostasis in aging. Furthermore, it provides a new framework for understanding how VSMC stiffness and adhesion to extracellular matrix contribute to arterial stiffness and how interactions with endothelial cells, platelets, and immune cells can regulate vascular aging. The identification of the key players of VSMC changes operating in large and small-sized arteries in response to increased mechanical load may be useful to better elucidate the causes and consequences of vascular aging and associated progression of hypertension, arteriosclerosis, and atherosclerosis.
From genetics to response to injury: vascular smooth muscle cells in aneurysms and dissections of the ascending aorta.
Michel Jean-Baptiste,Jondeau Guillaume,Milewicz Dianna M
Vascular smooth muscle cells (vSMCs) play a crucial role in both the pathogenesis of Aneurysms and Dissections of the ascending thoracic aorta (TAAD) in humans and in the associated adaptive compensatory responses, since thrombosis and inflammatory processes are absent in the majority of cases. Aneurysms and dissections share numerous characteristics, including aetiologies and histopathological alterations: vSMC disappearance, medial areas of mucoid degeneration, and extracellular matrix (ECM) breakdown. Three aetiologies predominate in TAAD in humans: (i) genetic causes in heritable familial forms, (ii) an association with bicuspid aortic valves, and (iii) a sporadic degenerative form linked to the aortic aging process. Genetic forms include mutations in vSMC genes encoding for molecules of the ECM or the TGF-β pathways, or participating in vSMC tone. On the other hand, aneurysms and dissections, whatever their aetiologies, are characterized by an increase in wall permeability leading to transmural advection of plasma proteins which could interact with vSMCs and ECM components. In this context, blood-borne plasminogen appears to play an important role, because its outward convection through the wall is increased in TAAD, and it could be converted to active plasmin at the vSMC membrane. Active plasmin can induce vSMC disappearance, proteolysis of adhesive proteins, activation of MMPs and release of TGF-β from its ECM storage sites. Conversely, vSMCs could respond to aneurysmal biomechanical and proteolytic injury by an epigenetic phenotypic switch, including constitutional overexpression and nuclear translocation of Smad2 and an increase in antiprotease and ECM protein synthesis. In contrast, such an epigenetic phenomenon is not observed in dissections. In this context, dysfunction of proteins involved in vSMC tone are interesting to study, particularly in interaction with plasma protein transport through the wall and TGF-β activation, to establish the relationship between these dysfunctions and ECM proteolysis.
Porcine complement regulators protect aortic smooth muscle cells poorly against human complement-induced lysis and proliferation: consequences for xenotransplantation.
Capey Steven,van den Berg Carmen W
BACKGROUND:Accelerated atherosclerosis after transplantation has been observed and is characterized by smooth muscle cell proliferation in the graft. Porcine cells are frequently used in models of atherosclerosis and porcine organs are considered for use in transplantation. Complement (C) activation is known to play a major role in rejection of xenografts and is also considered to play a role in the development of atherosclerosis. The aim of this study was to investigate the expression and function of membrane bound regulators of complement (CReg) on porcine aortic smooth muscle cells (PASMC). METHODS:The PASMC were assessed for expression of CReg and susceptibility to lysis by human C by flow-cytometry. The effect of various cytokines on CReg expression and C-susceptibility was investigated. The ability of human C to induce cell proliferation was assessed using the Alamar blue assay. RESULTS:The PASMC only express the CReg membrane cofactor protein (MCP) and CD59 on their cell surface. MCP expression was increased by interleukin (IL)-4. In contrast to porcine aortic endothelial cells (PAEC), PASMC were found to be surprisingly sensitive to C-mediated lysis, mainly due to a low level of expression of CD59. Human C-induced proliferation of PASMC, which was dependent on complete membrane attack complex (MAC) formation. CONCLUSIONS:Endogenously expressed CReg on PASMC poorly protect these cells to human C. Human C can induce proliferation of PASMC. In order to prevent accelerated atherosclerosis in porcine xenografts, increased levels of CReg not only have to be obtained on the endothelial cells but also on the smooth muscle cells.
Role of D and E domains in the migration of vascular smooth muscle cells into fibrin gels.
Kodama Michiteru,Naito Michitaka,Nomura Hideki,Iguchi Akihisa,Thompson W Douglas,Stirk Christina M,Smith Elspeth B
The structure of fibrin plays an important role in the organization of thrombi, the development of atherosclerosis, and restenosis after PTCA. In this study, we examined the mechanisms of the migration of vascular smooth muscle cells (SMCs) into fibrin gels, using an in vitro assay system. Cultured SMCs from bovine fetal aortic media migrated into fibrin gels prepared with thrombin, which cleaves both fibrinopeptides A and B from fibrinogen, without other chemotactic stimuli. Both desA fibrin gels prepared with batroxobin, which cleaves only fibrinopeptide A, and desB fibrin gels prepared with Agkistrodon contortrix thrombin-like enzyme (ACTE), which cleaves only fibrinopeptide B, similarly induced the migration of SMCs compared to fibrin gels prepared with thrombin. These results suggest that the cleavage of fibrinopeptides is not necessary, but rather that the three-dimensional structure of the gel may be important for the migration of SMCs. Furthermore, gels prepared with protamine sulfate, which forms fibrin-like gels non-enzymatically, similarly induced the migration of SMCs compared to the gels prepared with thrombin. Both anti-fibrin(ogen) fragment D and anti-fibrin(ogen) E antibodies inhibited the migration of SMCs into fibrin gels, suggesting that both the D and E domains of fibrin(ogen) are involved in the migration of SMCs into fibrin gels. The addition of GRGDS, a synthetic RGD-containing peptide, but not that of GRGES, a control peptide, partially inhibited the migration of SMCs into fibrin gels, suggesting that the migration of SMCs into fibrin gels is at least in part dependent on the RGD-containing region of the alpha chain. The migration of SMCs into fibrin gels was also inhibited by a monoclonal antibody for integrin alpha v beta 3 and alpha 5 beta 1, indicating that migration is dependent on these integrins. Furthermore, both fibrin(ogen) fragments D and E inhibited the migration of SMCs into fibrin gels, suggesting that these fragments, generated during fibrino(geno)lysis, may be relevant in the regulation of SMC migration into fibrin gels.
TRAIL expression in vascular smooth muscle.
Gochuico B R,Zhang J,Ma B Y,Marshak-Rothstein A,Fine A
American journal of physiology. Lung cellular and molecular physiology
TRAIL is a cell-associated tumor necrosis factor-related apoptosis-inducing ligand originally identified in immune cells. The ligand has the capacity to induce apoptosis after binding to cell surface receptors. To examine TRAIL expression in murine vascular tissue, we employed in situ hybridization and immunohistochemistry. In these studies, we found that TRAIL mRNA and protein were specifically localized throughout the medial smooth muscle cell layer of the pulmonary artery. Notably, a similar pattern of expression was observed in the mouse aorta. Consistent with these findings, we found that cultures of primary human aorta and pulmonary artery smooth muscle cells express abundant TRAIL mRNA and protein. We also found that these cells and endothelial cells undergo cell lysis in response to exogenous addition of TRAIL. Last, we confirmed that TRAIL specifically activated a death program by confirming poly(ADP ribose) polymerase cleavage. Overall, we believe that these findings are relevant to understanding the factors that regulate cell turnover in the vessel wall.
Nuclear factor-kappa B activation inhibits proliferation and promotes apoptosis of vascular smooth muscle cells.
Jiao Lei,Jiang Ming,Liu Jun,Wei Lichao,Wu Min
OBJECTIVES:To investigate the role of nuclear factor-kappa B (NF-κB) performed in cell proliferation and apoptosis of vascular smooth muscle cells (VSMCs), and to assess the mechanisms. METHODS:Human aorta VSMCs were divided into control, NF-κB inhibitor, NF-κB overexpression + NF-κB inhibitor, control vector + NF-κB inhibitor, NF-κB overexpression, and control vector groups. NF-κB overexpression vector was constructed and transfected into VSMCs. Proliferation of VSMCs in each group was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide. Apoptosis of VSMCs was detected by flow cytometry. The expression of NF-κB, FasL, and hypertension-related gene (HRG-1) was measured by Western blotting. RESULTS:NF-κB overexpression vector was constructed correctly by restriction endonuclease, and the results showed that the activation of NF-κB could inhibit the proliferation of VSMCs. The results of flow cytometry also confirmed that NF-κB overexpression promoted apoptosis of VSMCs. Mechanically, NF-κB overexpression could up-regulate the expression of FasL and HRG-1. CONCLUSIONS:NF-κB overexpression promotes apoptosis and inhibits cell proliferation of VSMCs. The mechanisms might be regulated by promoting FasL and HRG-1 expression.
Statin-mediated cholesterol depletion exerts coordinated effects on the alterations in rat vascular smooth muscle cell biomechanics and migration.
Sanyour Hanna J,Li Na,Rickel Alex P,Torres Haydee M,Anderson Ruthellen H,Miles Miranda R,Childs Josh D,Francis Kevin R,Tao Jianning,Hong Zhongkui
The Journal of physiology
KEY POINTS:This study demonstrates and evaluates the changes in rat vascular smooth muscle cell biomechanics following statin-mediated cholesterol depletion. Evidence is presented to show correlated changes in migration and adhesion of vascular smooth muscle cells to extracellular matrix proteins fibronectin and collagen. Concurrently, integrin α5 expression was enhanced but not integrin α2. Atomic force microscopy analysis provides compelling evidence of coordinated reduction in vascular smooth muscle cell stiffness and actin cytoskeletal orientation in response to statin-mediated cholesterol depletion. Proof is provided that statin-mediated cholesterol depletion remodels total vascular smooth muscle cell cytoskeletal orientation that may additionally participate in altering ex vivo aortic vessel function. It is concluded that statin-mediated cholesterol depletion may coordinate vascular smooth muscle cell migration and adhesion to different extracellular matrix proteins and regulate cellular stiffness and cytoskeletal orientation, thus impacting the biomechanics of the cell. ABSTRACT:Not only does cholesterol induce an inflammatory response and deposits in foam cells at the atherosclerotic plaque, it also regulates cellular mechanics, proliferation and migration in atherosclerosis progression. Statins are HMG-CoA reductase inhibitors that are known to inhibit cellular cholesterol biosynthesis and are clinically prescribed to patients with hypercholesterolemia or related cardiovascular conditions. Nonetheless, the effect of statin-mediated cholesterol management on cellular biomechanics is not fully understood. In this study, we aimed to assess the effect of fluvastatin-mediated cholesterol management on primary rat vascular smooth muscle cell (VSMC) biomechanics. Real-time measurement of cell adhesion, stiffness, and imaging were performed using atomic force microscopy (AFM). Cellular migration on extra cellular matrix (ECM) protein surfaces was studied by time-lapse imaging. The effect of changes in VSMC biomechanics on aortic function was assessed using an ex vivo myograph system. Fluvastatin-mediated cholesterol depletion (-27.8%) lowered VSMC migration distance on a fibronectin (FN)-coated surface (-14.8%) but not on a type 1 collagen (COL1)-coated surface. VSMC adhesion force to FN (+33%) and integrin α5 expression were enhanced but COL1 adhesion and integrin α2 expression were unchanged upon cholesterol depletion. In addition, VSMC stiffness (-46.6%) and ex vivo aortic ring contraction force (-40.1%) were lowered and VSMC actin cytoskeletal orientation was reduced (-24.5%) following statin-mediated cholesterol depletion. Altogether, it is concluded that statin-mediated cholesterol depletion may coordinate VSMC migration and adhesion to different ECM proteins and regulate cellular stiffness and cytoskeletal orientation, thus impacting the biomechanics of the cell and aortic function.
Thymoquinone suppresses platelet-derived growth factor-BB-induced vascular smooth muscle cell proliferation, migration and neointimal formation.
Zhu Ning,Xiang Yijia,Zhao Xuyong,Cai Changhong,Chen Hao,Jiang Wenbing,Wang Yi,Zeng Chunlai
Journal of cellular and molecular medicine
The excessive proliferation and migration of vascular smooth muscle cells (VSMCs) are mainly responsible for vascular occlusion diseases, such as pulmonary arterial hypertension and restenosis. Our previous study demonstrated thymoquinone (TQ) attenuated monocrotaline-induced pulmonary arterial hypertension. The aim of the present study is to systematically examine inhibitory effects of TQ on platelet-derived growth factor-BB (PDGF-BB)-induced proliferation and migration of VSMCs in vitro and neointimal formation in vivo and elucidate the potential mechanisms. Vascular smooth muscle cells were isolated from the aorta in rats. Cell viability and proliferation were measured in VSMCs using the MTT assay. Cell migration was detected by wound healing assay and Transwell assay. Alpha-smooth muscle actin (α-SMA) and Ki-67-positive cells were examined by immunofluorescence staining. Reactive oxygen species (ROS) generation and apoptosis were measured by flow cytometry and terminal deoxyribonucleotide transferase-mediated dUTP nick end labelling (TUNEL) staining, respectively. Molecules including the mitochondria-dependent apoptosis factors, matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 9 (MMP9), PTEN/AKT and mitogen-activated protein kinases (MAPKs) were determined by Western blot. Neointimal formation was induced by ligation in male Sprague Dawley rats and evaluated by HE staining. Thymoquinone inhibited PDGF-BB-induced VSMC proliferation and the increase in α-SMA and Ki-67-positive cells. Thymoquinone also induced apoptosis via mitochondria-dependent apoptosis pathway and p38MAPK. Thymoquinone blocked VSMC migration by inhibiting MMP2. Finally, TQ reversed neointimal formation induced by ligation in rats. Thus, TQ is a potential candidate for the prevention and treatment of occlusive vascular diseases.
Upregulation of the actin cytoskeleton via myocardin leads to increased expression of type 1 collagen.
Shi Zengdun,Rockey Don C
Laboratory investigation; a journal of technical methods and pathology
Liver fibrosis, a model wound healing system, is characterized by excessive deposition of extracellular matrix (ECM) in the liver. Although many fibrogenic cell types may express ECM, the hepatic stellate cell (HSC) is currently considered to be the major effector. HSCs transform into myofibroblast-like cells, also known as hepatic myofibroblasts in a process known as activation; this process is characterized in particular by de novo expression of smooth muscle alpha actin (SM α-actin) and type 1 collagen. The family of actins, which form the cell's cytoskeleton, are essential in many cellular processes. β-actin and cytoplasmic γ-actin (γ-actin) are ubiquitously expressed, whereas SM α-actin defines smooth muscle cell and myofibroblast phenotypes. Thus, SM α-actin is tightly associated with multiple functional properties. However, the regulatory mechanisms by which actin isoforms might regulate type 1 collagen remain unclear. In primary HSCs from normal and fibrotic rat liver, we demonstrate that myocardin, a canonical SRF cofactor, is upregulated in hepatic myofibroblasts and differentially regulates SM α-actin, γ-actin, and β-actins through activation of an ATTA box in the SM α-actin and a CCAAT box in γ-actin and β-actin promoters, respectively; moreover, myocardin differentially activated serum response factor (SRF) in CArG boxes of actin promoters. In addition, myocardin-stimulated Smad2 phosphorylation and RhoA expression, leading to increased expression of type 1 collagen in an actin cytoskeleton-dependent manner. Myocardin also directly enhanced SRF expression and stimulated collagen 1α1 and 1α2 promoter activities. In addition, overexpression of myocardin in vivo during carbon tetrachloride-induced liver injury led to increased HSC activation and fibrogenesis. In summary, our data suggest that myocardin plays a critical role in actin cytoskeletal dynamics during HSC activation, in turn, specifically regulating type I collagen expression in hepatic myofibroblasts.
Role of Vascular Smooth Muscle Cell Phenotypic Switching and Calcification in Aortic Aneurysm Formation.
Petsophonsakul Ploingarm,Furmanik Malgorzata,Forsythe Rachael,Dweck Marc,Schurink Geert Willem,Natour Ehsan,Reutelingsperger Chris,Jacobs Michael,Mees Barend,Schurgers Leon
Arteriosclerosis, thrombosis, and vascular biology
Aortic aneurysm is a vascular disease whereby the ECM (extracellular matrix) of a blood vessel degenerates, leading to dilation and eventually vessel wall rupture. Recently, it was shown that calcification of the vessel wall is involved in both the initiation and progression of aneurysms. Changes in aortic wall structure that lead to aneurysm formation and vascular calcification are actively mediated by vascular smooth muscle cells. Vascular smooth muscle cells in a healthy vessel wall are termed contractile as they maintain vascular tone and remain quiescent. However, in pathological conditions they can dedifferentiate into a synthetic phenotype, whereby they secrete extracellular vesicles, proliferate, and migrate to repair injury. This process is called phenotypic switching and is often the first step in vascular pathology. Additionally, healthy vascular smooth muscle cells synthesize VKDPs (vitamin K-dependent proteins), which are involved in inhibition of vascular calcification. The metabolism of these proteins is known to be disrupted in vascular pathologies. In this review, we summarize the current literature on vascular smooth muscle cell phenotypic switching and vascular calcification in relation to aneurysm. Moreover, we address the role of vitamin K and VKDPs that are involved in vascular calcification and aneurysm. Visual Overview- An online visual overview is available for this article.