Influence of Angiotensin II on α1-Adrenergic Receptors Function in Rat Aorta and Expression in Vascular Smooth Muscle Cells

Angiotensin II (Ang II) is the main mediator of the Renin-Angiotensin-System acting on AT1 and other AT receptors. It is regarded as a pleiotropic agent that induces many actions, including functioning as a growth factor, and as a contractile hormone, among others. The aim of this work was to examine the impact of Ang II on the expression and function of α1-adrenergic receptors (α1-ARs) in cultured rat aorta, and aorta-derived smooth muscle cells. Isolated Wistar rat aorta was incubated for 24 h in DMEM at 37˚C, then subjected to isometric tension and to the action of added norepinephrine, in concentration-response curves. Ang II was added (1 × 10−5 M), and in some experiments, 5-Methylurapidil (α1A-AR antagonist), AH11110A (α1B-AR antagonist), or BMY-7378 (α1D-AR antagonist), were used to identify the α1-AR involved in the response. Desensitization of the contractile response to norepinephrine was observed due to incubation time, and by the Ang II action. α1D-AR was protected from desensitization by BMY-7378;while RS-100329 and prazosin partially mitigated desensitization. In another set of experiments, isolated aorta-derived smooth muscle cells were exposed to Ang II and α1-ARs proteins were evaluated. α1D-AR increased at 30 and 60 min post Ang II exposure, the α1A-AR diminished from 1 to 4 h, while α1B-AR remained unchanged over 24 h of Ang II exposure. Ang II induced an increase of α1D-AR at short times, and BMY-7378 protected α1D-AR from desensitization.

Semaphorin 7A promotes human vascular smooth muscle cell proliferation and migration through theβ-catenin signaling pathway

Background:Vascular smooth muscle cells(VSMCs)undergo a conversion from a contractile phenotype to a proliferative synthetic phenotype,contributing to the pathogenesis of cardiovascular diseases.Semaphorin 7A(SEMA7A)is a glycosylphosphatidylinositol-anchored membrane protein that plays an important role in vascular homeostasis by regulating endothelial cell behaviors.However,the expression and role of SEMA7A in VSMCs remain unclear.Methods:In this study,we screened for VSMC-regulating genes in publicly available datasets and analyzed the expression of SEMA7A in human coronary artery smooth muscle cells(hCASMCs)treated with platelet-derived growth factor-BB(PDGF-BB).The effects of SEMA7A overexpression and knockdown on hCASMC proliferation and migration were examined.The signaling pathways involved in the action of SEMA7A in hCASMCs were determined.Results:Bioinformatic analysis showed that SEMA7A was significantly dysregulated in VSMCs treated with oxidized low-density lipoprotein or overexpressing progerin,a pro-atherogenic gene.The PDGF-BB stimulation led to a concentration-and time-dependent induction of SEMA7A.Depletion of SEMA7A attenuated PDGF-BB-induced hCASMC proliferation and migration.Conversely,overexpression of SEMA7A enhanced hCASMC proliferation and migration.Mechanistically,SEMA7A stimulated the activation of theβ-catenin pathway and upregulated c-Myc,CCND1,and MMP7.Knockdown ofβ-catenin impaired SEMA7A-induced hCASMC proliferation and migration.Conclusions:SEMA7A triggers phenotype switching in VSMCs through theβ-catenin signaling pathway and may serve as a potential therapeutic target for cardiovascular diseases.

Inhibitory Effect of PPARδAgonist GW501516 on Proliferation of Hypoxia-induced Pulmonary Arterial Smooth Muscle Cells by Regulating the mTOR Pathway

Objective This study aimed to investigate the effects of the peroxisome proliferator-activated receptorδ(PPARδ)agonist GW501516 on the proliferation of pulmonary artery smooth muscle cells(PASMCs)induced by hypoxia,in order to search for new drugs for the treatment and prevention of pulmonary vascular remodeling.Methods PASMCs were incubated with different concentrations of GW501516(10,30,100 nmol/L)under the hypoxic condition.The proliferation was determined by a CCK-8 assay.The cell cycle progression was analyzed by flow cytometry.The expression of PPARδ,S phase kinase-associated protein 2(Skp2),and cell cycle-dependent kinase inhibitor p27 was detected by Western blotting.Then PASMCs were treated with 100 nmol/L GW501516,100 nmol/L mammalian target of rapamycin(mTOR)inhibitor rapamycin and/or 2µmol/L mTOR activator MHY1485 to explore the molecular mechanisms by which GW501516 reduces the proliferation of PASMCs.Results The presented data demonstrated that hypoxia reduced the expression of PPARδin an oxygen concentration-and time-dependent manner,and GW501516 decreased the proliferation of PASMCs induced by hypoxia by blocking the progression through the G0/G1 to S phase of the cell cycle.In accordance with these findings,GW501516 downregulated Skp2 and upregulated p27 in hypoxia-exposed PASMCs.Further experiments showed that rapamycin had similar effects as GW501516 in inhibiting cell proliferation,arresting the cell cycle,regulating the expression of Skp2 and p27,and inactivating mTOR in hypoxia-exposed PASMCs.Moreover,MHY1485 reversed all the beneficial effects of GW501516 on hypoxia-stimulated PASMCs.Conclusion GW501516 inhibited the proliferation of PASMCs induced by hypoxia through blocking the mTOR/Skp2/p27 signaling pathway.

A bioinformatics-based study of the mechanism of JQ-1 on BET protein and atherosclerosis induced by vascular smooth muscle cell proliferation

Background:Based on previous theoretical studies,JQ-1 as a common inhibitor of bromodomain and extraterminal(BET)proteins was used to treat a variety of diseases.Therefore,we aimed to explore the mechanism of action of JQ-1 on BET proteins based on bioinformatics and build the novel hypothesis of JQ-1 in treating atherosclerosis(AS)caused by proliferation of vascular smooth muscle cells(VSMCs).Methods:We selected the chip GSE138323 which was searched with the key words“Vascular smooth muscle cell proliferation”in Gene Expression Omnibus(GEO)database,and differential gene analysis was performed between the GRO and JQ-1 groups.Then the top twenty significantly up-regulated genes and the top twenty significantly down-regulated genes were selected for Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis.Thirdly,structured the PPI network of forty differential genes,and the core genes were screened by using the MCC algorithm which in“Cytohubba”plugin in the Cytoscapev3.9.1 software.After that,single gene Gene Set Enrichment Analysis(GSEA)enrichment analysis was performed on the selected core genes in R language.Finally molecular docking validation was performed.Results:Five core genes was selected:H3C2,H3C4,H3C7,H3C10 and AREG.The GO enrichment analysis results showed that there were twenty-five entries in biological process,eight entries in cellular components(CC),and twenty-five entries in molecular function.The KEGG enrichment analysis results showed that there were seven pathways,mainly including systemic lupus erythematosus and external neutrophil trap formation.The GSEA results showed that the five genes were mainly through the regulation of cytochrome P450 metabolism,PPAR signaling pathway and other pathways.The molecular docking results showed that JQ-1 had binding activity with these five genes.Conclusions:JQ-1 may regulate the expression of the genes that H3C2,H3C4,H3C7,H3C10 and AREG,to mainly regulate the genes in cytochrome P450 metabolism,PPAR singling pathway and other pathways,to make some influence in the proliferation of VSMCs,and improved atherosclerotic symptoms due to vascular smooth muscle proliferation,thus treating cardiovascular disease.

Influence of Osteopontin Short Hairpin RNA on the Proliferation and Activity of Rat Vascular Smooth Muscle Cells

To investigate the influence of osteopontin （OPN） short hairpin RNA （shRNA） on the proliferation and activity of rat vascular smooth muscle cells （VSMCs）, the expressing vector of shRNA targeting OPN was constructed and transferred into the rat VSMCs. After amplification and purification, pGenesil-1/OPNshRNA1 （PG1）, pGenesil-1/OPNshRNA2 （PG2） and pGenesil-1/OPNshRNAHK （PGH） were transfected into the cultured rat VSMC by LipofectamineTM 2000. Transfected cells were visualized by using an inverted fluorescent microscope. VSMCs transfected by optimal recombined plasmid was selected by culturing in G418 48 h later. Nude cells and cells transfected by PGH were used as control. The expression levels of OPN mRNA and protein were assayed by RT-PCR and Western blotting. The OPN of VSMCs was suppressed by transfection of optimal recombined plasmid, and the changes in cell proliferation, adhesion and motility were evaluated by MTT, adhesion test and transwell chamber test. Levels of type I and Ⅲ collagen were measured with ELISA kit. Our results showed that VSMCs stably transfected by OPN shRNA accounted for over 50% of total cells. OPN mRNA and protein were reduced by 81% and 67% （P〈0.01） by PG1, 73% and 52% （P〈0.01） by PG2, respectively while no change was found in PGH and non-treated VSMCs. PG1 significantly suppressed the proliferation, adhesion, mobility of VSMCs and reduced the amount of type Ⅰ and Ⅲ collagen. It is concluded that recombinant plasmid can be success-fully transfected into VSMCs by LipofectamineTM 2000 and inhibit the expression of OPN. The proliferation, adhesion and mobility of VSMCs can be inhibited by knocking down OPN expression. Moreover, the transferring capability of cells is attenuated, and the secretion of type Ⅰ and Ⅲ collagen is inhibited aftter knocking-down of OPN expression. The study provides experimental evidence for clinical prevention of restenosis after percutaneous coronary intervention （PCI） by RNA interference （RNAi） technology.

Inhibitory Effects of Suppressor of Cytokine Signaling 3 on Inflammatory Cytokine Expression and Migration and Proliferation of IL-6/IFN-γ-induced Vascular Smooth Muscle Cells

Summary： The main pathogenesis of saphenous vein graft neointimal hyperplasia after coronary artery bypass grafting （CABG） is inflammation-caused migration and proliferation of vascular smooth muscle cells （VSMCs）. Janus kinase 2/signal transducer and activators of transcription 3 （JAK2/STAT3） path- way is an important signaling pathway through which VSMCs phenotype conversion occurs. Suppressor of cytokine signaling 3 （SOCS3） is the classic negative feedback inhibitor of JAK2/STAT3 pathway. Growing studies show that SOCS3 plays an important anti-inflammatory role in numerous autoimmune diseases, inflammatory diseases and inflammation-related tumors. However, the effect and mechanism of SOCS3 on vein graft disease is unclear. The purpose of this study was to investigate the effects of SOCS3 on the inflammation, migration and proliferation of VSMCs in vitro and the mechanism. The small interference RNA plasmid targeting rat SOCS3 （SiRNA-rSOCS3） and the recombinant adenovirus vector carrying rat SOCS3 gene （pYrAd-rSOCS3） were constructed, and the empty plamid （SiRNA-control） and vector （pYrAd-GFP） only carrying GFP reported gene were constructed as control. The rat VSMCs were cultured. There were two large groups of A （SOCS3 up-regulated）： control group, IL-6/IFN-γ group, IL-6/IFN-γ＋pYrAd-rSOCS3 group, IL-6/IFN-γ＋pYrAd-GFP group; and B （SOCS3 down-regulated）： control group, IL-6/IFN-γ group, IL-6/IFN-γ＋SiRNA-rSOCS3 group and IL-6/IFN -T＋SiRNA-control group. The pYrAd-rSOCS3 and SiRNA-rSOCS3 were transfected into VSMCs in- duced by IL-6/IFN-γ. After 24 h, real-time reverse transcription polymerase chain reaction （RT-PCR） and Western blotting were used to detect the mRNA and protein expression of SOCS3, STAT3 （only by Western blotting）, P-STAT3 （only by Western blotting）, IL-1β, IL-6, TNF-α, MCP-1 and ICAM-1. The MTT, Transwell assay and flow cytometry were used to examine VSMCs proliferation, migration and cell cycle progression, respectively. As compared with control group, the mRNA and protein expression of SOCS3, STAT3, P-STAT3, IL-1β, IL-6, TNF-α, MCP-1 and ICAM-1 was significantly up-regulated in VSMCs stimulated by IL-6/IFN-γ. However, in VSMCs transfected with pYrAd-rSOCS3 before stimulation with IL-6/IFN-γ, the expression of SOCS3 mRNA and protein was further up-regulated, and that of STAT3, P-STAT3, IL-1β, IL-6, TNF-α, MCP-1 and ICAM-1 was significantly down-regulated as compared with IL-6/IFN-γ group and IL-6/IFN-γ＋pYrAd-GFP group. The expression of those re- lated-cytokines in IL-6/IFN-γ＋SiRNA-rSOCS3 group was markedly increased as compared with IL-6/IFN-γ group and IL-6/IFN-γ＋SiRNA-control group. The absorbance （A） values, the number of cells migrating to the lower chamber, and percentage of cells in the G2/M＋S phase were increased in VSMCs stimulated by IL-6/IFN-γ. In VSMCs incubated with pYrAd-rSOCS3 or SiRNA-rSOCS3 be- fore IL-6/IFN-γ stimulation, the A values, the number of cells migrating to the lower chamber, and the percentage of cells in the G2/M＋S phase were significantly decreased, and increased respectively. These results imply that IL-6/IFN-γ, strong inflammatory stimulators, can promote transformation of VSMCs phenotype form a quiescent contractile state to a synthetic state by activating JAK2/STAT3 pathway. Over-expresssed SOCS3 might inhibit pro-inflammatory effect, migration and growth of VSMCs by blocking STAT3 activation and phosphorylation. These data in vitro confirm that SOCS3 may play a negatively regulatory role in development and progression of vein graft failure. These conclusions can provide a novel strategy for clinical treatment of vein graft diseases and a new theoretic clue for related drug development.

Valsartan Inhibits Angiotensin Ⅱ-induced Proliferation of Vascular Smooth Muscle Cells via Regulating the Expression of Mitofusin 2

Angiotensin Ⅱ (ANGⅡ) plays an important role in the pathogenesis of atherosclerosis by inducing proliferation of vascular smooth muscle cells (VSMCs).In our study,we observed the effects of valsartan on proliferation of cultured VSMCs treated with or without ANGⅡ by cell counting and methyl thiazolyl tetrazolium (MTT) assay,and detected the expression of mitofusin 2 (Mfn2),a newly discovered cell proliferation inhibitor and a related cell proliferation signaling pathway pro-tein by Western blotting.ANGⅡ at a concentration of 10-6 mol/L significantly stimulated VSMCs proliferation,down-regulated the expression of Mfn2 and upregulated the expression of Raf and ERK1/2.Valsartan inhibited such effects of ANGⅡ at concentrations of 10-5 and 10-6 mol/L,but not at 10-7 mol/L.Valsartan had no significant effect on the proliferation of untreated VSMCs.These results suggest that valsartan inhibits ANGⅡ-induced proliferation of VSMCs in vitro via Mfn2-Ras-Raf-ERK/MAPK signaling pathway.

Artesunate Reduces Proliferation, Interferes DNA Replication and Cell Cycle and Enhances Apoptosis in Vascular Smooth Muscle Cells

Summary: This study examined the effect of artesunate (Art) on the proliferation, DNA replication, cell cycles and apoptosis of vascular smooth muscle cells (VSMCs). Primary cultures of VSMCs were established from aortas of mice and artesunate of different concentrations was added into the medium. The number of VSMCs was counted and the curve of cell growth was recorded. The activity of VSMCs was assessed by using MTT method and inhibitory rate was calculated. DNA replication was evaluated by [3H]-TdR method and apoptosis by DNA laddering and HE staining. Flowmetry was used for simultaneous analysis of cell apoptosis and cell cycles. Compared with the control group, VSMCs proliferation in Art interfering groups were inhibited and [3H]-TdR incorprating rate were decreased as well as cell apoptosis was induced. The progress of cell cycle was blocked in G 0/G 1 by Art in a dose-dependent manner. It is concluded that Art inhibits VSMCs proliferation by disturbing DNA replication, inducing cell apoptosis and blocking cell cycle in G 0/G 1 phase.

Eukaryotic Expression of Human Arresten Gene and Its Effect on the Proliferation of Vascular Smooth Muscle Cells

The eukaryotic expression of human arresten gene and its effect on the proliferation of in vitro cultured vascular smooth cells （VSMCs） in vitro were investigated. COS-7 cells were transfected with recombinant eukaryotic expression plasmid pSecTag2-AT or control plasmid pSecTag2 mediated by liposome. Forty-eight h after transfection, reverse transcription-polymerase chain reaction （RT-PCR） was used to detect the expression of arresten mRNA in the cells, while Western blot assay was applied to detect the expression of arresten protein in concentrated supernatant. Primary VSMCs from thoracic aorta of male Sprague-Dawley rats were cultured using the tissue explant method, and identified by immunohistochemical staining with a smooth muscle-specific anti-α- actin monoclonal antibody before serial subcuhivation. VSMCs were then co-cultured with the concentrated supernatant and their proliferation was detected using Cell Counting Kit-8 （CCK-8） in vitro. The results showed that RT-PCR revealed that the genome of arresten-transfected cells contained a 449 bp specific fragment of arresten gene, suggesting the successful transfection. Success- ful protein expression in supernatants was confirmed by Western blot. CCK-8 assay showed that the proliferation of VSMCs were inhibited significantly by arresten protein as compared with control cells （F=40. 154, P〈0.01）. It was concluded that arresten protein expressed in eukaryotic cells can inhibit proliferation of VSMCs effectively in vitro, which would provide possibility to the animal experiments.

Effects of caffeic acid phenethyl ester on proliferation of vascular smooth muscle cells in rats

Objective： To investigate the inhibitory effect of caffeic acid phenethyl ester（CAPE） on the proliferation of vascular smooth muscle cells （VSMC） activated by lipopolysaccharide （LPS） and to clarify its mechanism. Methods： VSMC activated by LPS （1 mg-L^-1） were treated with CAPE at different concentrations. The inhibitory effecfs of CAPE on the proliferation of VSMC were determined by methabenzthiazuron（MTT） colorimetry. The effects of CAPE on the expression of proliferating cell nuclear antigen （PCNA） and Survivin protein in VSMC were evaluated by immunocytochemistry staining technique （SABC method）. Cell cycle was analyzed by flow cytometry（FCM） with propidiumiodide （PI） labeling method. The relative expression level of Survivin mRNA was measured with real-time quantified RT-PCR technique. Results. CAPE exerted significant inhibitory effects on. proliferation of VSMC at concentrations ranging from 5 mg·L^-1 to 80 mg·L^-1, decreased the rate of cells positive for PCNA and Survivin protein and repressed the expressioh of Survivin mRNA in a dose- and time-dependent manner （P 〈 0.05）. FCM analysis displayed that CAPE up-regulated the ratio of G0/G1 stages and reduced the percentage of VSMC in S stage （P 〈 0.05）. Conclusion： CAPE can significantly inhibit the proliferation of VSMC activated by LPS in a dose- and time-dependent manner, which may be carded out through regulating cell cycle and repressing the expression of PCNA and Survivin.

Glycosylation-independent binding to extracellular domains 11-13 of mannose-6-phosphate/insulin-like growth factor-2 receptor mediates the effects of soluble CREG on the phenotypic proliferation of vascular smooth muscle cells

Background The present study aimed to investigate the detailed mode and specific sites for their binding as well as the functional relevance of this binding in the phenotypic proliferation of vascular smooth muscle cells(SMCs). Methods CREG knocked-down SMCs were employed to evaluate the biological activity of wtCREG and mCREG.Expressions of SMC differentiation markers SM myosin heavy chain(SM-MHC),SM-actin,heavy caldesmon and myocardin were determined by Western blotting using specific antibodies. Cellular growth of SMCs was assessed by bromide dewuridine (BrdU) incorporation and cell cycle analysis on fluorescence-activated cell sorting(FACS).A solid-phase binding assay was used to study the binding of CREG to extracellular domains of M6P/IGF2R.The cellular co-localization of the two recombinant CREGs with M6P/IGF2R was detected on SMC surface by immunoprecipitation and immunofluorescence analysis.Results The molecular weight of wtCREG was around 30 kD while that of the mCREG was～25 kD.Treatment of wtCREG with PNGase F reduced its molecular weight from～30 kD to～25 kD,whereas PNGase F treatment had no effect on the molecular weight of mCREG.Both wtCREG and mCREG proteins enhanced SMC differentiation,inhibited BrdU incorporation,and arrested cell cycle progression when added to the culture medium.In CREG knocked-down SMCs,the amount of CREG detected by immunoblotting in M6P/IGF2R immunoprecipitates was significantly reduced when compared to normal cells.Both recombinant CREGs co-immunoprecipitated with M6P/IGF2R, although slightly reduced amount of the mutant CREG was detected in M6P/IGF2R immunoprecipitates.Immunostaining revealed that His-tagged CREGs co-localized with IGF2R on the cell surface in a glycosylation-independent manner.In vitro binding assay showed that CREGs bound to M6P/ IGF2R extracellular domains 7-10 and 11-13 in a glycosylation -dependent and -independent manner,respectively.Further blocking experiments using soluble M6P/IGF2R fragments and M6P/IGF2R neutralizing antibody indicated that the biological activities of recombinant CREGs in SMC growth and the up-regulation of SMC differentiation markers were all abolished by treatment with the M6P/IGF2R neutralizing antibody. However,although the growth inhibitory effect of wtCREG was nearly abolished by D7-10 or D11-13,the effect of mCREG was only reversed by Dll-13,indicating that the binding to domains 11-13 is required for CREG to modulate the proliferation of SMCs.Conclusions These data suggest that solubleCREG proteins can exert their biological function via binding to the extracellular domains 7-10 and 11-13 of cell surface M6P/IGF2R in both a glycosylation-dependent and -independent manner.

Insulin induces PKC-dependent proliferation of mesenteric vascular smooth muscle cells from hypertensive patients

Background and objectives Proliferation of human vascular smooth muscle cells (VSMCs) induced by hyperinsulinemia is a very common clinical pathology. Extensive research has focused on PKC (Protein kinase C)-MAPK (mitogen-activated protein kinase)intracellular signal transduction and the phenotypic modulation accompanied by reorganization of intracellular F-actins in VSMCs.Methods DNA synthesis, signaling of ERK1/2 MAPKs, and changes in α-smooth muscle (SM) actin and F-actin were studied in hypertensive and normotensive human arterial VSMCs exposed to insulin and PMA with and without the PKC inhibitor, GF109203X.Results Differences among cell types in MAPK signaling, α-SM actin, and F-actin isoforms in VSMCs harvested from the arteries of patients with essential hypertension (EH) and normotension (NT) were identified in response to insulin treatment. Proliferation and activation of MAPK were more pronounced in EH VSMCs than in NEH VSMCs. Insulin exposure decreased expression of α-SM actin and was accompanied by rearrangement of intracellular F-actins in VSMCs, especially in the EH group. These effects were reversed by treatment with the PKC inhibitor. Conclusions Human mesenteric VSMCs of EH and NT patients differed in proliferation, MAPK signaling, and degree of changes in α-SM actin and F-actin isoforms immediately following insulin exposure in vitro.

Inhibitory Effects of Roscovitine on Proliferation and Migration of Vascular Smooth Muscle Cells In Vitro

Abnormal proliferation and migration of vascular smooth muscle cells （VSMCs） are the major cause of in-stent restenosis （ISR）. Intervention proliferation and migration of VSMCs is an im- portant strategy for antirestenotic therapy. Roscovitine, a second-generation cyclin-dependent kinase in- hibitor, can inhibit cell cycle of multiple cell types. We studied the effects of roscovitine on cell cycle distribution, proliferation and migration of VSMCs in vitro by flow cytometry, BrdU incorporation and wound healing assay, respectively. Our results showed that roscovitine increased the proportion of Go/G1 phase cells after 12 h （69.57±3.65 vs. 92.50±1.68, P=0.000）, 24 h （80.87±2.24 vs. 90.25±0.79, P=0.000） and 48 h （88.08±3.86 vs. 88.87±2.43, P=-0.427） as compared with control group. Roscovifine inhibited proliferation and migration of VSMCs in a concentration-dependent way. With the increase of concen- tration, roscovitine showed increased capacity for growth and migration inhibition. Roscovitine （30 μmol/L） led to an almost complete VSMCs growth and migration arrest. Combined with its low toxicity and selective inhibition to ISR-VSMCs, roscovitine may be a potential drug in the treatment of vascular stenosis diseases and particularly useful in the prevention and treatment of ISR.

MicroRNA-146a Promotes Embryonic Stem Cell Differentiation towards Vascular Smooth Muscle Cells through Regulation of Kruppel-like Factor 4

Objective Vascular smooth muscle cell(VSMC)differentiation from stem cells is one source of the increasing number of VSMCs that are involved in vascular remodeling-related diseases such as hypertension,atherosclerosis,and restenosis.MicroRNA-146a(miR-146a)has been proven to be involved in cell proliferation,migration,and tumor metabolism.However,little is known about the functional role of miR-146a in VSMC differentiation from embryonic stem cells(ESCs).This study aimed to determine the role of miR-146a in VSMC differentiation from ESCs.Methods Mouse ESCs were differentiated into VSMCs,and the cell extracts were analyzed by Western blotting and RT-qPCR.In addition,luciferase reporter assays using ESCs transfected with miR-146a/mimic and plasmids were performed.Finally,C57BL/6J female mice were injected with mimic or miR-146a-overexpressing ESCs,and immunohistochemistry,Western blotting,and RT-qPCR assays were carried out on tissue samples from these mice.Results miR-146a was significantly upregulated during VSMC differentiation,accompanied with the VSMC-specific marker genes smooth muscle-alpha-actin(SMαA),smooth muscle 22(SM22),smooth muscle myosin heavy chain(SMMHC),and h1-calponin.Furthermore,overexpression of miR-146a enhanced the differentiation process in vitro and in vivo.Concurrently,the expression of Kruppel-like factor 4(KLF4),predicted as one of the top targets of miR-146a,was sharply decreased in miR-146a-overexpressing ESCs.Importantly,inhibiting KLF4 expression enhanced the VSMC-specific gene expression induced by miR-146a overexpression in differentiating ESCs.In addition,miR-146a upregulated the mRNA expression levels and transcriptional activity of VSMC differentiation-related transcription factors,including serum response factor(SRF)and myocyte enhancer factor 2c(MEF-2c).Conclusion Our data support that miR-146a promotes ESC-VSMC differentiation through regulating KLF4 and modulating the transcription factor activity of VSMCs.

Increased serum TREM-1 level is associated with in-stent restenosis,and activation of TREM-1 promotes inflammation,proliferation and migration in vascular smooth muscle cells

Background and Objective In-stent restenosis(ISR)remains a major limitation of percutaneous coronary intervention despite improvements in stent design and pharmacological agents,whereas the mechanism of ISR has not been fully clarified.In the present study,we sought to investigate the potential association of serum soluble TREM-1(sTREM-1)levels with the incidence of ISR.The role of TREM-1 was evaluated in cultured vascular smooth muscle cells(VSMCs).

Effect of ^(125)I seeds and ^(103)Pd stents on proliferation of vascular smooth muscle cells

This study aims at the theoretical and practical evidence for prevention of restenosis in vitro.Vascular smooth muscle cell(VSMC)model was established using adherent cell culture methods.The proliferation of VSMC was investigated by the cell counting method and 3H-TDR implementation test.The results are as follows.(1) For ^125I-seeds,the inhibition rate was 29.3% at 74B1(P<0.05),35.2% at 148Bq(P<0.05)and 42.4% at 370Bq(P<0.05),For ^103Pd-implanted stents,the inhibition rate was 14.7% at 4.44MBq(P<0.05),24.0% at 5.92MBq(P<0.05) and 38.0%at 7.4MBq(p<0.05),There was no significant difference between the blank tests and non-radioactive tests.(2) 48 hours exposure from ^125I-seeds at 148Bq or ^103Pd-implanted stents at 7.4MBq did not result in VSMC's morphological alteration,but that from ^125I-seeds at 370Bq caused morphological changes,Both ^125I-seeds and ^103Pd0-implanted stents inhibit the VSMC DNA synthesis in vitro.The inhibition effects are significantly related to their exposure duration and doses.

Effect of hammerhead ribozyme that specifically cleaves c-myc mRNA on proliferation of vascular smooth muscle cells

Ojective: To investigate the effect of hammerhead ribozyme that specifically cleaves c-myc mRNA on the proliferation of vascular smooth muscle cells (VSMCs). Methods: Based on the computer analysis of the secondary structure of c-myc mRNA, nt 2029 in rat c-myc oncogene was selected as a cleaving site for hammerhead ribozyme and the ribozyme was designed. With automatic DNA synthesizer, the two complementary DNA strands of the ribozyme were synthesized. The ribozyme gene was cloned into pGEM3Zf (+) vector and subcloned into eukaryotic expression pcDNA3 vector. The recombinant pcDNA-Rz was transfected into the cultured rat VSMCs by lipofectAMINE mediated DNA transfection protocol and individual cell clones were selected by G418. Results: The sequence of ribozyme gene inserted in pGEM3Zf (+) vector was proved to be perfectly correct. In VSMCs transfected with recombinant pcDNA-Rz, flow cytometry analysis showed that the S phase and G2/M fractions were decreased significantly and cell proliferation stagnated in the G0/G1 phase. Conclusion: The results suggest that hammerhead ribozyme that specifically cleaves c-myc mRNA can significantly inhibit the proliferation of VSMCs.

Overexpression of heme oxygenasel protects smooth muscle cells against oxidative injury and inhibits cell proliferation

To investigate whether the expression of exogenous heme oxygenase-1 (HO-l) gene within vascular smooth muscle cells (VSMC) could protect the cells from free radical attack and inhibit cell proliferation,we established an in vitro transfection of human HO-1 gene into rat VSMC mediated by a retroviral vector.The results showed that the profound expression of HO-1 protein as well as HO activity was 1.8- and 2.0-fold increased respectively in the transfected cells compared to the non-transfected ones. The treatment of VSMC with different concentrations of H2O2 led to the remarkable cell damage as indicated by survival rate and LDH leakage. However, the resistance of the HO-1 transfected VSMC against H2O2 was significantly raised. This protective effect was dramatically diminished when the transfected VSMC were pretreated with ZnPP-IX, a specific inhibitor of HO, for 24 h. In addition, we found that the growth potential of the transfected cells was significantly inhibited directly by increased activity of HO-l, and this effect might be related to decreased phosphorylation of MAPK. These results suggest that the overexpression of introduced hHO-1 is potentially able to reduce the risk factors of atherosclerosis, partially due to its cellular protection against oxidative injury and to its inhibitory effect on cellular proliferation.