Vascular Smooth Muscle Cell Function Research Articles

Role of S-Equol, Indoxyl Sulfate, and Trimethylamine N-Oxide on Vascular Function.

Gut microbiota have been emerging as important contributors to the regulation of host homeostasis. Accordingly, several substances converted by gut microbiota can have beneficial or adverse effects on human health. Among them, S-equol, which is produced from the isoflavone daidzein in the human and animal gut by certain microbiota, exerts estrogenic and antioxidant activities. Indoxyl sulfate, which is metabolized in the liver from indole converted from dietary tryptophan by bacterial tryptophanases in the colon, is known as a protein-bound uremic toxin. Trimethylamine N-oxide, which is generated via the oxidization of gut microbiota-derived trimethylamine by hepatic flavin monooxygenases, is known as an accelerator of atherosclerosis. The aforementioned gut-derived substances could be potential regulators of systematic tissue/organ function, including the vascular system. Macro- and microvascular complications of cardiovascular and metabolic diseases, including atherosclerosis, hypertension, and diabetes, occur systemically and represent the principal cause of morbidity and mortality. Vascular endothelial and smooth muscle dysfunction play pivotal roles in the development and progression of vasculopathies. We herein review the link between the aforementioned gut-derived substances and endothelial and vascular smooth muscle cell function. This information will provide a conceptual framework that would allow the development of novel preventive and/or therapeutic approaches against vasculopathies.

MicroRNA-204-5p Participates in Atherosclerosis Via Targeting MMP-9.

The aim of the present study was to investigate the role and mechanism of microRNA-204-5p (miR-204-5p) in atherosclerosis (AS)-related abnormal human vascular smooth muscle cells (hVSMCs) function. Firstly, we analyzed the expression of miR-204-5p and found that the miR-204-5p expression level was clearly downregulated in atherosclerotic plaque tissues and blood samples compared to the normal controls. Then, matrix metallopeptidase-9 (MMP-9) was predicted to be the potential target of miR-204-5p by TargetScan and this prediction was confirmed by luciferase assays. Besides, we observed that miR-204-5p could negatively regulate the expression of MMP-9 in hVSMCs. Subsequently, Thiazolyl Blue Tetrazolium Bromide (MTT) assay, transwell assay and flow cytometry were performed to detect the proliferation, migration and apoptosis of hVSMCs. Down-expression of miR-204-5p led to the promotion of proliferation and migration accompanied with the suppression of apoptosis in hVSMCs, and these effects were reversed by MMP-9-siRNA. In addition, overexpressed miR-204-5p could inhibit hVSMC proliferation and migration and promote the apoptosis of hVSMCs. However, the effects were also abrogated by overexpressed MMP-9. Together, our findings showed that miR-204-5p plays an important role in the growth and migration of hVSMCs by targeting MMP-9, which might be a novel biomarker and promising therapeutic target for AS.

Coronary Artery Spasm: The Interplay Between Endothelial Dysfunction and Vascular Smooth Muscle Cell Hyperreactivity.

Patients with angina pectoris, the cardinal symptom of myocardial ischaemia, yet without significant flow-limiting epicardial artery stenosis represent a diagnostic and therapeutic challenge. Coronary artery spasm (CAS) is an established cause for anginal chest pain in patients with angiographically unobstructed coronary arteries. CAS may occur at the epicardial level and/or in the microvasculature. Although the underlying pathophysiological mechanisms of CAS are still largely unclear, endothelial dysfunction and vascular smooth muscle cell (VSMC) hyperreactivity seem to be involved as major players, although their contribution to induce CAS is still seen as controversial. This article will look at the role and possible mechanistic interplay between an impaired endothelial and VSMC function in the pathogenesis of CAS.

The Role of Ubiquitin E3 Ligase in Atherosclerosis.

Atherosclerosis is a chronic inflammatory vascular disease. Atherosclerotic cardiovascular disease is the main cause of death in both developed and developing countries. Many pathophysiological factors, including abnormal cholesterol metabolism, vascular inflammatory response, endothelial dysfunction and vascular smooth muscle cell proliferation and apoptosis, contribute to the development of atherosclerosis and the molecular mechanisms underlying the development of atherosclerosis are not fully understood. Ubiquitination is a multistep post-translational protein modification that participates in many important cellular processes. Emerging evidence suggests that ubiquitination plays important roles in the pathogenesis of atherosclerosis in many ways, including regulation of vascular inflammation, endothelial cell and vascular smooth muscle cell function, lipid metabolism and atherosclerotic plaque stability. This review summarizes important contributions of various E3 ligases to the development of atherosclerosis. Targeting ubiquitin E3 ligases may provide a novel strategy for the prevention of the progression of atherosclerosis.

Regulation of KCNMA1 transcription by Nrf2 in coronary arterial smooth muscle cells

The large conductance Ca2+-activated K+ (BK) channels, composed of the pore-forming α subunits (BK-α, encoded by KCNMA1 gene) and the regulatory β1 subunits (BK-β1, encoded by KCNMB1 gene), play a unique role in the regulation of coronary vascular tone and myocardial perfusion by linking intracellular Ca2+ homeostasis with excitation-contraction coupling in coronary arterial smooth muscle cells (SMCs). The nuclear factor erythroid 2-related factor 2 (Nrf2) belongs to a member of basic leucine zipper transcription factor family that regulates the expression of antioxidant and detoxification enzymes by binding to the antioxidant response elements (AREs) of these target genes. We have previously reported that vascular BK-β1 protein expression was tightly regulated by Nrf2. However, the molecular mechanism underlying the regulation of BK channel expression by Nrf2, particularly at transcription level, is unknown. In this study, we hypothesized that KCNMA1 and KCNMB1 are the target genes of Nrf2 transcriptional regulation. We found that BK channel protein expression and current density were diminished in freshly isolated coronary arterial SMCs of Nrf2 knockout (KO) mice. However, BK-α mRNA expression was reduced, but not that of BK-β1 mRNA expression, in the arteries of Nrf2 KO mice. Promoter-Nrf2 luciferase reporter assay confirmed that Nrf2 binds to the ARE of KCNMA1 promoter, but not that of KCNMB1. Adenoviral expression and pharmacological activation of Nrf2 increased BK-α and BK-β1 protein levels and enhanced BK channel activity in coronary arterial SMCs. Hence, our results indicate that Nrf2 is a key determinant of BK channel expression and function in vascular SMCs. Nrf2 facilitates BK-α expression through a direct increase in gene transcription, whereas that on BK-β1 is through a different mechanism.

Adenosine kinase is critical for neointima formation after vascular injury by inducing aberrant DNA hypermethylation.

Adenosine receptors and extracellular adenosine have been demonstrated to modulate vascular smooth muscle cell (VSMC) proliferation and neointima formation. Adenosine kinase (ADK) is a major enzyme regulating intracellular adenosine levels but is function in VSMC remains unclear. Here, we investigated the role of ADK in vascular injury-induced smooth muscle proliferation and delineated the mechanisms underlying its action. We found that ADK expression was higher in the neointima of injured vessels and in platelet-derived growth factor-treated VSMCs. Genetic and pharmacological inhibition of ADK was enough to attenuate arterial injury-induced neointima formation due to inhibition of VSMC proliferation. Mechanistically, using infinium methylation assays and bisulfite sequencing, we showed that ADK metabolized the intracellular adenosine and potentiated the transmethylation pathway, then induced the aberrant DNA hypermethylation. Pharmacological inhibition of aberrant DNA hypermethylation increased KLF4 expression and suppressed VSMC proliferation as well as the neointima formation. Importantly, in human femoral arteries, we observed increased ADK expression and DNA hypermethylation as well as decreased KLF4 expression in neointimal VSMCs of stenotic vessels suggesting that our findings in mice are relevant for human disease and may hold translational significance. Our study unravels a novel mechanism by which ADK promotes VSMC proliferation via inducing aberrant DNA hypermethylation, thereby down-regulating KLF4 expression and promoting neointima formation. These findings advance the possibility of targeting ADK as an epigenetic modulator to combat vascular injury.

MicroRNA-24-3p inhibition prevents cell growth of vascular smooth muscle cells by targeting Bcl-2-like protein 11.

Numerous reports have shown that dysfunction of vascular smooth muscle cells (VSMCs) serves a critical function in the development of cardiovascular disease, including coronary heart disease (CHD). microRNAs (miRNAs/miRs) have been reported to play important roles in regulating the function of VSMCs. The present study aimed to determine the role of miR-24-3p in VSMCs and to uncover the underlying mechanism. The expression of miR-24-3p in the peripheral blood samples of CHD patients was measured by reverse transcription-quantitative (RT-q)PCR. It was found that the level of miR-24-3p in the peripheral blood of patients with CHD was significantly upregulated compared with that in healthy controls. A dual luciferase reporter assay was performed to determine whether Bcl-2-like protein 11 (Bcl-2L11) was a target gene of miR-24-3p, and it was identified that Bcl-2L11 was a direct target of miR-24-3p. The mRNA level and protein expression of Bcl-2L11 in the peripheral blood of patients with CHD were measured by RT-qPCR and western blotting, respectively. The findings suggested that Bcl-2L11 was downregulated in the peripheral blood of patients with CHD. In addition, it was found that downregulation of miR-24-3p suppressed VSMC proliferation and promoted VSMC apoptosis, while the effects of the miR-24-3p inhibitor on cell viability and apoptosis were reversed by Bcl-2L11-small interfering (si)RNA. Additionally, downregulation of miR-24-3p increased the levels of Bcl-2L11, caspase-3 and Bax, and decreased Bcl-2 expression in VSMCs; these changes were abolished by Bcl-2L11-siRNA. In conclusion, the aforementioned results indicated that miR-24-3p was an important regulator in VSMC proliferation and apoptosis by targeting Bcl-2L11, which suggested that miR-24-3p might be a potential therapeutic target for the treatment of CHD.

Loss of smooth muscle α-actin effects on mechanosensing and cell-matrix adhesions.

Mutations in ACTA2, encoding smooth muscle α-actin, are a frequent cause of heritable thoracic aortic aneurysm and dissections. These mutations are associated with impaired vascular smooth muscle cell function, which leads to decreased ability of the cell to sense matrix-mediated mechanical stimuli. This study investigates how loss of smooth muscle α-actin affects cytoskeletal tension development and cell adhesion using smooth muscle cells explanted from aorta of mice lacking smooth muscle α-actin. We tested the hypothesis that reduced vascular smooth muscle contractility due to a loss of smooth muscle α-actin decreases cellular mechanosensing by dysregulating cell adhesion to the matrix. Assessment of functional mechanical properties of the aorta by stress relaxation measurements in thoracic aortic rings suggested two functional regimes for Acta2−/−mice. Lower stress relaxation was recorded in aortic rings from Acta2−/−mice at tensions below 10 mN compared with wild type, likely driven by cytoskeletal-dependent contractility. However, no differences were recorded between the two groups above the 10 mN threshold, since at higher tension the matrix-dependent contractility may be predominant. In addition, our results showed that at any given level of stretch, transmural pressure is lower in aortic rings from Acta2−/−mice than wild type mice. In addition, a three-dimensional collagen matrix contractility assay showed that collagen pellets containing Acta2−/−smooth muscle cells contracted less than the pellets containing the wild type cells. Moreover, second harmonic generation non-linear microscopy revealed that Acta2−/−cells locally remodeled the collagen matrix fibers to a lesser extent than wild type cells. Quantification of protein fluorescence measurements in cells also showed that in absence of smooth muscle α-actin, there is a compensatory increase in smooth muscle γ-actin. Moreover, specific integrin recruitment at cell–matrix adhesions was reduced in Acta2−/−cells. Thus, our findings suggest that Acta2−/−cells are unable to generate external forces to remodel the matrix due to reduced contractility and interaction with the matrix.Impact statementThoracic aneurysm formation is characterized by progressive enlargement of the ascending aorta, which predisposes the aorta to acute aortic dissection that can lead to sudden death. SMCs in the aorta play an integral role in regulating vessel wall contractility and matrix deposition in the medial layer. Recent studies show that mutations in genes associated with actomyosin apparatus reduce SMC contractility, increasing susceptibility to TAAD. Single-cell experiments enable discrete measurements of transient microscopic events that may be masked by a macroscopic average tissue behavior. Biophysical methods combined with microscopy techniques aid in understanding the specific roles of adhesion and cytoskeletal proteins in regulating SMC mechanosensing when SMα-actin is disrupted. Our findings suggest that Acta2−/−cells have increased SMγ-actin and decreased integrin recruitment at cell–matrix adhesion, hence a synthetic phenotype with reduced cellular mechanosensing.

Tuning mitochondrial structure and function to criticality by fluctuation-driven mechanotransduction

Cells in vascular walls are exposed to blood pressure variability (BPV)-induced cycle-by-cycle fluctuations in mechanical forces which vary considerably with pathology. For example, BPV is elevated in hypertension but reduced under anesthesia. We hypothesized that the extent of mechanical fluctuations applied to vascular smooth muscle cells (VSMCs) regulates mitochondrial network structure near the percolation transition, which also influences ATP and reactive oxygen species (ROS) production. We stretched VSMCs in culture with cycle-by-cycle variability in area strain ranging from no variability (0%), as in standard laboratory conditions, through abnormally small (6%) and physiological (25%) to pathologically high (50%) variability mimicking hypertension, superimposed on 0.1 mean area strain. To explore how oxidative stress and ATP-dependent metabolism affect mitochondria, experiments were repeated in the presence of hydrogen peroxide and AMP-PNP, an ATP analog and competitive inhibitor of ATPases. Physiological 25% variability maintained activated mitochondrial cluster structure at percolation with a power law distribution and exponent matching the theoretical value in 2 dimensions. The 25% variability also maximized ATP and minimized cellular and mitochondrial ROS production via selective control of fission and fusion proteins (mitofusins, OPA1 and DRP1) as well as through stretch-sensitive regulation of the ATP synthase and VDAC1, the channel that releases ATP into the cytosol. Furthermore, pathologically low or high variability moved mitochondria away from percolation which reduced the effectiveness of the electron transport chain by lowering ATP and increasing ROS productions. We conclude that normal BPV is required for maintaining optimal mitochondrial structure and function in VSMCs.

Curcumin inhibits proliferation, migration and neointimal formation of vascular smooth muscle via activating miR-22

Context Curcumin has antitumor, antioxidative, anti-inflammatory, and anti-proliferative properties. Objective To investigate the role of miR-22 during curcumin-induced changes in vascular smooth muscle cells (VSMC) and neointima formation in balloon-injured rat abdominal aorta. Materials and methods Sprague-Dawley rats were randomised to the sham-operated (n = 10), operated control (injured, n = 10), and curcumin treatment (n = 10) groups. miR-22 expression was determined by real-time PCR. SP1 was assessed by western blot and real-time PCR. Rat aortic smooth muscle A7r5 cells were used to determine VSMC proliferation and migration, which were measured by the MTS, EdU staining, Transwell, and wound healing assays. Results miR-22 levels declined following arterial balloon injury in vivo (48% at 3d, p < 0.05) and serum stimulation in vitro (45% at 24 h, p < 0.01). Functional studies revealed that miR-22 negatively regulated the proliferation and migration of VSMCs by directly targeting the SP1 transcription factor in VSMCs. Curcumin increased the expression of miR-22 (81%, p < 0.05) and decreased the protein expression of SP1 in VSMCs (25%, p < 0.05). miR-22 inhibition was found to attenuate the effects of curcumin on VSMC functions. Curcumin increased miR-22 (46%, p < 0.01), decreased the SP1 protein (19%, p < 0.05), and inhibited vascular neointimal area (48%, p < 0.01) in vivo. Discussion The miR-22/SP1 pathway is involved in the protective role of curcumin during arterial balloon injury, but the mechanisms remain unclear. Conclusion miR-22 is involved in the inhibitory effects of curcumin on VSMCs’ proliferation, migration and neointima hyperplasia after arterial balloon injury in rats. Curcumin could be used to prevent neointimal hyperplasia after angioplasty.

Roles and Functions of Exosomal Non-coding RNAs in Vascular Aging.

Aging is a progressive loss of physiological integrity and functionality process which increases susceptibility and mortality to diseases. Vascular aging is a specific type of organic aging. The structure and function changes of endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are the main cause of vascular aging, which could influence the threshold, process, and severity of vascular related diseases. Accumulating evidences demonstrate that exosomes serve as novel intercellular information communicator between cell to cell by delivering variety biologically active cargos, especially exosomal non-coding RNAs (ncRNAs), which are associated with most of aging-related biological and functional disorders. In this review, we will summerize the emerging roles and mechanisms of exosomal ncRNAs in vascular aging and vascular aging related diseases, focusing on the role of exosomal miRNAs and lncRNAs in regulating the functions of ECs and VSMCs. Moreover, the relationship between the ECs and VSMCs linked by exosomes, the potential diagnostic and therapeutic application of exosomes in vascular aging and the clinical evaluation and treatment of vascular aging and vascular aging related diseases will also be discussed.

Role of smooth muscle cells in Cardiovascular Disease.

Normally, smooth muscle cells (SMCs) are localized in the tunica media of the vasculature, where they take responsibility for vascular contraction and extracellular matrix (ECM) generation. SMCs also play a significant role in obedience and elastic rebound of the artery in response to the haemodynamic condition. However, under pathological or stressed conditions, phenotype switching from contractile to synthetic state or other cell types will occur in SMCs to positively or negatively contribute to disease progression. Various studies demonstrated that functional changes of SMCs are implicated in several cardiovascular diseases. In this review, we present the function of vascular SMCs (VSMCs) and the involved molecular mechanisms about phenotype switching, and summarize the roles of SMCs in atherosclerosis, hypertension, arterial aneurysms and myocardial infarction, hoping to obtain potential therapeutic targets against cardiovascular disease in the clinical practices.

Downregulation of miRNA-1-3p modulates cyclic stretch-mediated proliferation of vascular smooth muscle cells through regulation of ETS-1

Mechanical stretch modulates the proliferation of vascular smooth muscle cells (VSMCs) and plays an important role in the pathogenesis of hypertension, but the underlying mechanisms are unclear. We investigated the role of microRNA- 1-3p (miRNA-1-3p) on the proliferation of VSMCs induced by mechanical cyclic stretch. Our data show that miRNA-1-3p is downregulated in the aorta of the spontaneous hypertension rat (SHR). Pathological mechanical stretch at 15% suppressed the expression of miRNA-1-3p, calponin and SM22, but enhanced the proliferation of VSMCs as well as the expression of the V-ets erythroblastosis virus E26 oncogene homolog 1 (ETS-1), collagen type I alpha (Col-1a), collagen type III alpha (Col-3a) and elastin. Overexpression of miRNA-1-3p inhibited cell proliferation and induced the expression of calponin and SM22, but decreased the expression of ETS-1, Col-1a, Col-3a and elastin. Mechanical stretch at 15% combined with losartan treatment increased the expression of miRNA-1-3p, calponin and SM22, and decreased the expression of ETS-1, Col-1a and Col-3a. Dual luciferase reporter assays revealed ETS-1 as a direct target of miRNA-1-3p. These findings suggest that miRNA-1-3p regulates VSMC function through ETS-1 regulation during hypertension-induced vascular remodeling. MiRNA-1-3p may be a viable therapeutic target for hypertension.

Notch3 signalling and vascular remodelling in pulmonary arterial hypertension.

Notch signalling is critically involved in vascular morphogenesis and function. Four Notch isoforms (Notch1–4) regulating diverse cellular processes have been identified. Of these, Notch3 is expressed almost exclusively in vascular smooth muscle cells (VSMCs), where it is critically involved in vascular development and differentiation. Under pathological conditions, Notch3 regulates VSMC switching between the contractile and synthetic phenotypes. Abnormal Notch3 signalling plays an important role in vascular remodelling, a hallmark of several cardiovascular diseases, including pulmonary arterial hypertension (PAH). Because of the importance of Notch3 in VSMC (de)differentiation, Notch3 has been implicated in the pathophysiology of pulmonary vascular remodelling in PAH. Here we review the current literature on the role of Notch in VSMC function with a focus on Notch3 signalling in pulmonary artery VSMCs, and discuss potential implications in pulmonary artery remodelling in PAH.

ER stress and Rho kinase activation underlie the vasculopathy of CADASIL.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) leads to premature stroke and vascular dementia. Mechanism-specific therapies for this aggressive cerebral small vessel disease are lacking. CADASIL is caused by NOTCH3 mutations that influence vascular smooth muscle cell (VSMC) function through unknown processes. We investigated molecular mechanisms underlying the vasculopathy in CADASIL focusing on endoplasmic reticulum (ER) stress and RhoA/Rho kinase (ROCK). Peripheral small arteries and VSMCs were isolated from gluteal biopsies of CADASIL patients and mesentery of TgNotch3R169C mice (CADASIL model). CADASIL vessels exhibited impaired vasorelaxation, blunted vasoconstriction, and hypertrophic remodeling. Expression of NOTCH3 and ER stress target genes was amplified and ER stress response, Rho kinase activity, superoxide production, and cytoskeleton-associated protein phosphorylation were increased in CADASIL, processes associated with Nox5 upregulation. Aberrant vascular responses and signaling in CADASIL were ameliorated by inhibitors of Notch3 (γ-secretase inhibitor), Nox5 (mellitin), ER stress (4-phenylbutyric acid), and ROCK (fasudil). Observations in human CADASIL were recapitulated in TgNotch3R169C mice. These findings indicate that vascular dysfunction in CADASIL involves ER stress/ROCK interplay driven by Notch3-induced Nox5 activation and that NOTCH3 mutation–associated vascular pathology, typical in cerebral vessels, also manifests peripherally. We define Notch3-Nox5/ER stress/ROCK signaling as a putative mechanism-specific target and suggest that peripheral artery responses may be an accessible biomarker in CADASIL.

Activation of CD137 signaling promotes neointimal formation by attenuating TET2 and transferrring from endothelial cell-derived exosomes to vascular smooth muscle cells

Activated endothelial cells (ECs) play an important role in the development of atherosclerosis (AS) because they form neointima resulting from abnormal vascular smooth muscle cell (VSMC) hyperplasia. TET2 was recently reported as a major regulator of the phenotypic switch of VSMCs, and it also protects ECs from noxious stimuli and represses inflammation in AS. The purpose of the present study is to determine whether activation of CD137 signaling can regulate the function of VSMCs by altering endothelial TET2 expression and to explore the potential mechanisms. VSMCs were isolated from C57BL/6 J mice, and the influence of ECs on VSMCs was analyzed using a co-culture system. Western blotting was used to detect the protein expression levels of TET2 and CD9, CD81, and CD63 as well as VSMC phenotypic markers. RT-PCR was performed to detect the TET2 mRNA levels. EdU proliferation assay and transwell migration assay were employed to assess the functions of VSMCs. EXO-spin kits were used to extract and purify exosomes. Transmission electron microscopy and nanoparticle tracking analysis were applied to characterize exosomes. ECs transduced with the TET2-overexpression lentivirus showed that the activation of endothelial CD137 signaling decreased TET2 expression and the TET2 content in exosomes. EC-derived exosomes were internalized by VSMCs, which inhibited phenotypic switching in vitro and neointimal formation in vivo. However, exosomes derived from CD137-activated ECs exhibited weakened protective effects on VSMCs. In conclusion, activation of endothelial CD137 signaling attenuated the repressive effects of EC-derived exosomes on platelet-derived growth factor (PDGF)-BB-induced phenotypic switching of VSMCs and neointimal formation after carotid injury.

Long noncoding RNA-dependent regulation of vascular smooth muscle cell proliferation and migration in hypertension.

Hypertension is one of the main risks causing cardiovascular diseases. Long noncoding RNAs (lncRNAs) play a critical role in many physiological and pathological conditions. However, their role in hypertension is still unclear. In this study, 460 lncRNAs and 522 mRNA were identified to have different expressions in the thoracic aortas of spontaneously hypertensive rats compared with normotensive Wistar-Kyoto rats through next-generation sequencing. Several randomly selected lncRNAs including NONRATT011842 were validated by qRT-PCR and their potential functions were predicted by co-expression analysis with the help of bioinformatics. Moreover, this study focused on the function of lncRNA NONRATT011842 in the vascular smooth muscle cells (VSMCs) during hypertension and confirmed that NONRATT011842 could interact with PABPC1 to regulate the functions of VSMCs. Therefore, the intervention or utilization of certain lncRNAs could be a new biomarker for the diagnosis and prevention of hypertension.

Pterostilbene Attenuates Experimental Atherosclerosis through Restoring Catalase-Mediated Redox Balance in Vascular Smooth Muscle Cells.

Atherosclerosis, the major risk of cardiovascular events, is a chronic vascular inflammatory disease. Pterostilbene is a naturally occurring dimethylated analogue of resveratrol and has recently been demonstrated to be beneficial against cardiovascular diseases. However, the underlying mechanisms of pterostilbene on atherosclerosis remain elusive. Experimental atherosclerosis was induced by a high-fat diet (HFD) in apolipoprotein E knockout (ApoE-/-) mice. Pterostilbene was administered intragastrically for 16 weeks. We found that pterostilbene significantly attenuated thoracic and abdominal atherosclerotic plaque formation in HFD-fed ApoE-/-mice, accompanied by modulated lipid profiles and reduced production of proinflammatory cytokines (including IL-6, IFN-γ, and TNF-α). In addition, pterostilbene restored vascular redox balance in thoracic and abdominal aorta, evidenced by enhanced catalase (CAT) expression and activities, and decreased malondialdehyde and H2O2 production. Notably, pterostilbene specifically induced CAT expression and activities in the vascular smooth muscle cells (VSMCs) of thoracic and abdominal aorta. In vitro, pterostilbene markedly promoted the expression and activity of CAT and decreased ox-low-density lipoprotein (LDL)-mediated VSMC proliferation and intracellular H2O2 production, which was abolished by CAT siRNA knockdown or inhibition. Pterostilbene-induced CAT expression was associated with inhibition of Akt, PRAS40, and GSK-3β signaling activation and upregulation of PTEN. Our data clearly demonstrated that pterostilbene exerted an antiatherosclerotic effect by inducing CAT and modulating the VSMC function.

MiR-149-5p Inhibits Vascular Smooth Muscle Cells Proliferation, Invasion, and Migration by Targeting Histone Deacetylase 4 (HDAC4).

BackgroundStudies have demonstrated that microRNAs (miRNAs) have essential roles in biological functions of vascular smooth muscle cells (VSMCs). However, the function and related molecular mechanism of miR-149-5p in VSMCs remains unclear.Material/MethodsWe used MTT assay, Transwell assay, and wound-healing assay to measure the proliferation, invasion, and migration of VSMCs transfected with miR-149-5p mimics or inhibitors, respectively. Bioinformatics tools and luciferase assay were used to validate the relationship between miR-149-5p and histone deacetylase 4 (HDAC4). Rescue experiments were used to confirm the interaction of miR-149-5p and HDAC4 in regulating biological functions in VSMCs.ResultsmiR-149-5p was downregulated in PDGF-bb-induced VSMCs. It was also found that miR-149-5p overexpression suppressed proliferation, invasion, and migration of VSMCs, while miR-149-5p knockdown showed the opposite effects. Furthermore, HDAC4 was found to be a potential target of miR-149-5p, which rescued miR-149-5p-mediated proliferation, invasion, and migration in VSMCs.ConclusionsWe demonstrated that miR-149-5p can suppress biological functions of VSMCs by regulating HDAC4, which might provide a potent therapeutic target for VSMC growth-related diseases.

Nrf-2 signaling inhibits intracranial aneurysm formation and progression by modulating vascular smooth muscle cell phenotype and function

BackgroundOxidative stress and vascular smooth muscle cell (VSMC) phenotypic modulation influence intracranial aneurysm (IA) formation and progression. Oxidative stress plays an important role in phenotype switching, and nuclear factor erythroid 2-related factor 2 (Nrf-2) is one of the main antioxidant systems. Unfortunately, little is known about how Nrf-2 signaling influences VSMC phenotype switches during IA pathogenesis.MethodsWe examined the effect of Nrf-2 activation IA on formation and progression in an elastase-induced rat IA model. We also developed a hydrogen peroxide (H2O2)-induced VSMC oxidative damage model. Then, we analyzed VSMC phenotype changes in the setting of Nrf-2 activation or inhibition in vitro. The proliferation, migration ability, and apoptosis rate of VSMCs were tested. Lastly, we measured the expression levels of antioxidant enzymes and inflammatory cytokines downstream of Nrf-2.ResultsNrf-2 activation suppressed IA formation and progression in vivo. We confirmed Nrf-2 nuclear translocation and a VSMC switch from the contractile to synthetic phenotype. Nrf-2 activation inhibited the proliferation, migratory ability, and apoptosis rate enhanced by H2O2. Quantitative real-time polymerase chain reaction (PCR) and western blot analysis revealed that Nrf-2 activation promoted antioxidant enzymes and VSMC-specific marker gene expressions but decreased pro-inflammatory cytokine levels.ConclusionThese results suggest that Nrf-2 exerts protective effects against IA development by preventing VSMCs from changing to a synthetic phenotype.