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.

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.

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 Saponins From Anemarrhena asphodeloides Bunge on the Growth of Vascular Smooth Muscle Cells

Objective To investigate the effects of saponins from Anemarrhena asphodeloides Bunge （SAaB） （Botanical Name： Anemarrhena Asphodeloidis Rhizoma） on the growth of vascular smooth muscle cells （VSMCs）. Methods Cell proliferation was measured by a newly developed cell proliferation reagent, WST-1. Cell apoptosis was assayed by flow cytometry through detecting annexin V. Nitric oxide production was evaluated using confocal laser scanning microscopy with diaminofluorescein diacetate （DAF-2, DA）. Cell aldose reductase （AR） activity, as well as the effect of Epalrestat and interleukin-1β were also explored. Results WST assay showed that cell proliferation induced by serum was significantly inhibited by SAaB （P〈0.01）. Flow cytometry analysis revealed that SAaB could enhance apoptotic rate of VSMCs （P〈0.01）. Nitric oxide production was significantly enhanced after administration of SAaB and interleukin-Iβ Moreover, AR activity of VSMCs was also remarkably inhibited by both SAaB and Epalrestat （P〈 0.01）. Conclusion SAaB can inhibit proliferation and enhance apoptosis of VSMCs. It may protect vascular cells by inhibiting VSMC proliferation and augmenting apoptotic rate of VSMCs via NO-dependent pathway.

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.

Construction of human eukaryotic expression plasmid vascular endothelial growth factor 165 and its expression in transfected vascular smooth muscles

BACKGROUND: The highly specific vascular endothelialgrowth factor (VEGF) induces the growth of vascular en-dothelial cell. This study was to construct the eukaryoticexpression plasmid of vascular endothelial growth factorl65(VEGF165) and observe its expression in vascular smoothmuscles (VSMCs).METHODS: The primers were designed and synthesizedaccording to the gene sequences of human VEGF165. TheVEGF165 gene was obtained from umbilic artery tissue bythe method of RT-PCR, then it was cloned to eukaryoticexpression plasmid pBudCE4.1 by recombination strategy.The eukaryotic expression plasmid named pBudCE4.1/VEGF165 was identified by restriction enzyme digestion,and was sequenced. The pBudCE4.1/VEGF165 was trans-fected into VSMCs by using lipofection. The VEGF165 ex-pression of mRNA and protein was detected by RT-PCRand Western blot respectively.RESULTS: VEGF165 was shown about 576bp by RT-PCR.Sequencing revealed the amplified VEGF165 gene was iden-tical with that in the GeneBank. Restrictive enzyme (HindBam HI) digestion analysis showed that recombinantexpression plasmid pBudCE4. l/tVEGF165 had been con-structed successfully. The expression of VEGF165 at mRNAand protein levels in the transformed VSMCs had beendemonstrated by RT-PCR and Western blot.CONCLUSIONS: The recombinant eukaryotic expressionplasmid pBudCE4.1/VEGF165 has been successfully con-structed and expressed in transformed VSMCs. The presentstudy has laid a foundation for VEGF165 gene therapy ofvascular stenosis in the transplant organ.

Homocysteine-induced Enhanced Expression of Tissue Factor in Human Vascular Smooth Muscle Cells

The homocysteine （Hcy）-induced tissue factor （TF） expression in human vascular smooth muscle cells （VSMCs） and the effect of Hcy on the activity of nuclear factor-kappaB （NF-кB） and the expression of inducible nitric oxide synthase （iNOS） were investigated. Human umbilical artery VSMCs were cultured by tissue explanting method, identified by α-actin immunohistochemistry, and incubated with different concentrations of Hcy/PTDC （NF-кB inhibitor）. Semi-quantitative RT-PCR was performed to detect the expression of TF mRNA in VSMCs. Flow cytometry was used to assay the expression of TF protein on the surface of VSMCs and the expression of iNOS in VSMCs. Western blot was carried out to detect the expression of NF-кB protein in nuclei. The results showed that Hcy could induce VSMCs expressing TF mRNA significantly after the VSMCs were incubated with Hcy at concentrations of 10, 100, 500 μmol/L respectively. There was low expression level of TF protein on the surface of the resting VSMCs and Hcy could also induce VSMCs expressing TF pro- tein on the cell surface in different concentrations. Additionally, Hcy could rapidly induce the activation of NF-кB and this effect could be significantly inhibited by PDTC. Hcy alone could not induce the expression of iNOS in VSMCs. It was concluded that Hcy could significantly induce the expression of TF in VSMCs and enhance the activation of NF-ΚB, subsequently mediate TF gene expression and protein synthesis. NF-кB-mediated expression of TF in VSMCs might be the important mechanism of atherosclerosis and thrombosis induced by Hcy.

Effects of Total Flavonoids ofHippophae RhamnoidesL.on Intracellular Free Calciumin Cultured Vascular Smooth Muscle Cells of Spontaneously Hypertensive Rats and Wistar-Kyoto Rats

To explore the effects of total flavonoids of Hippophae rhamnoides L. （TFH） quercetin （Que） and isorhamnetin （Isor） on the intracellular free calcium （[Ca^2＋]） in vascular smooth muscle cells （VSMC） of spontaneously hypertensive rats （SHR） and Wistar-Kyoto rats （WKY）. Metheds： Fluo 3-acetoxymethylester（Fluo-3/AM） was used to observe the effects of TFH （100mg/L） and its essential monomers, namely Que （10^-4mol/L） and Isor （10^-4mol/L） on changes of [Ca^2＋]1 in cultured SHR and WKY VSMC （abbr. to Ca-SHR ＆ Ca-WKY） following exposure to high K^＋, norepinephrine （NE） and angiotensin Ⅱ （AngⅡ）, and to compare with the effects of verapamil （Ver）. Results： （1） TFH, Que and Isor had inhibitory effects on resting Ca-SHR （P〈0.05）, but had no significant effects on Ca-WKY （P〉0.05）. （2） High K^＋ could increase Ca-SHR more significantly than Ca-WKY （P〈0.05）; TFH, Que and Isor could inhibit the elevation of [Ca^2＋]1 induced by high K^＋ -depolarization, with the effects similar to that of Ver, and the effect on Ca-SHR was more significant than that on Ca-WKY （P〈0.05）. （3） NE and Ang Ⅱ could increase Ca-SHR more significantly than Ca-WKY （P〈0.05）, TFH, Que and Isor had remarkably inhibitory effect on the elevation of Ca-SHR and Ca-WKY induced by NE or Ang Ⅱ. （4） In the absence of extracellular Ca^2＋ , TFH, Que and Isor also had certain inhibitory effect on Ca-SHR and Ca-WKY induced by NE, and the effect on the former was more significant than that on the latter（P〈0.05）. Ceaclusiea： TFH, Que and Isor might decrease the levels of [Ca^2＋], in VSMCs by blocking both voltage-dependent calcium channels （VDC） and receptoroperated calcium channels （ROC） in physiological or pathological state, which may be one of the important mechanisms of their hypotensive and protective effects on target organs in patients with hypertension.

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.

Different Responses of Cell Cycle between Rat Vascular Smooth Muscle Cells and Vascular Endothelial Cells to Paclitaxel

Summary： Although previous reports showed dmg-eluting stent （DES） could effectively inhibit neointima formation, in-stent restenosis （ISR） remains an important obstacle. The purpose of this study was to investigate different effects of paclitaxel on proliferation and cell cycle regulators between vascular smooth muscle cells （VSMCs） and vascular endothelial cells （VECs） of rats in vitro. The cultured VSMCs and VECs of rats from the same tissues were examined by using immunohistochemistry, flow cytometry and Western blotting in control and paclitaxel-treated groups. The results showed paclitaxel could effectively inhibit proliferation of VSMCs and VECs. However, as compared with VECs, prolif- eration of VSMCs in paclitaxel-treated group decreased less rapidly. The percentage of cells in G0-G1 and G2-M phases was reduced, and that in S phase increased after treatment for 72 h. The expression of cyclin D1 and B1, p27 and PCNA in VSMCs of paclitaxel-treated group was up-regulated, but that of p21 down-regulated as compared with VECs. It is concluded that there are significant differences in the expression of cell cycle regulators and proliferation rate between paclitaxel-treated VSMCs and paclitaxel-treated VECs, suggesting that the G1 S checkpoint regulated by paclitaxel may play a critical role in the development of complications of DES, which provides new strategies for treatments of ISR.

Resveratrol inhibits angiotensin II-induced ERK1/2 activation by downregulating quinone reductase 2 in rat vascular smooth muscle cells

Our previous studies showed that resveratrol could inhibit the proliferation of vascular smooth muscle cells （VSMCs） and repress mRNA and protein expression of quinone reductase 2 （NQO2）. This study further explored the potential mechanisms whereby resveratrol inhibits the proliferation of rat VSMCs. Lentiviral vectors that incorporated NQO2 small interfering RNA （siRNA） were constructed and transduced into rat VSMCs. The cell proliferation was detected using the bromodeoxyuridine （BrdU） assay. Cultured rat VSMCs were stimulated with angiotensin II and the level of reactive oxygen species （ROS） was measured using a ROS assay kit. A realtime quantitative PCR was used to detect NQO2 mRNA levels. Extracellular signal-regulated kinase （ERK1/2） and NQO2 protein expression were determined by Western blotting analysis. The inhibitory effect of resveratrol （10 and 50 μmol/L） on the proliferation of rat VSMCs in the NQO2 siRNA group was significantly weaker than that in the normal and scrambled siRNA group （P 〈 0.01）. The ROS level in the NQO2 siRNA and resveratrol （50 μmol/L） treatment groups were lower than that in the normal and scrambled siRNA groups （P 〈 0.01 in both）. Compared with the normal and scrambled siRNA group, the phosphorylation of ERK1/2 was significantly decreased in the NQO2 siRNA and resveratrol （50 μmol/L） treatment group （P 〈 0.01 in both）. In conclusion, high concentration of resveratrol inhibits angiotensin II-induced ERK1/2 phosphorylation and subsequent proliferation by down-regulation of NQO2 in cultured rat VSMCs.

Mitofusin2 Decreases Intracellular Cholesterol of Oxidized LDL-Induced Foam Cells from Rat Vascular Smooth Muscle Cells

Mitofusin2 （Mfn2） plays a pivotal role in the proliferation and apoptosis of vascular smooth muscle cells （VSMCs）. The purpose of this study was to investigate the effects of Mfn2 on the traffick- ing of intracellular cholesterol in the foam ceils derived from rat VSMCs （rVSMCs） and also to investigate the effects of Mfn2 on the expression of adenosine triphosphate-binding cassette subfamily A member 1 （ABCA1）, adenosine triphosphate-binding cassette subfamily G member 1 （ABCG1） and peroxisome proliferator-activated receptor gamma （PPARy）. The rVSMCs were co-cultured with oxi- dized low density lipoprotein （LDL, 80 ~tg/mL） to produce foam cells and cholesterol accumulation in cells. Before oxidized LDL treatment, different titers （20, 40 and 60 pfu/cell） of recombinant adenovirus containing Mfn2 gene （Adv-Mfn2） were added into the culture medium for 24 h to transfect the Mfn2 gene into the rVSMCs. Then the cells were harvested for analyses. The protein expression of Mfn2 was significantly higher in Adv-Mfn2-transfected group than in untransfected group （P〈0.05）, and the ex- pression levels significantly increased when the titer of Adv-Mfn2 increased （P〈0.05）. At 24 or 48 h af- ter oxidized LDL treatment, rVSMCs became irregular and their nuclei became larger, and their plasma abounded with red lipid droplets. However, the number of red lipid droplets was significantly decreased in Adv-Mfn2-transfected group as compared with untransfected group. At 48 h after oxidized LDL treatment, the intracellular cholesterol in rVSMCs was significantly increased （P〈0.05）, but it was sig- nificantly decreased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）, and it also significantly decreased when the titer of Adv-Mfn2 increased （P〈0.05）. The mRNA and pro- tein expression levels of ABCA1 and ABCG1 were significantly increased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）. Though the mRNA and protein expression levels of PPARy was not significantly increased （P〉0.05）, the phosporylation levels of PPARy were signifi- cantly decreased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）. These results suggest that the transfection of Adv-Mfn2 can significantly reduce intracellular cholesterol in oxidized LDL-induced rVSMCs possibly by decreasing PPAR＇/phosporylation and then increasing pro- tein expression levels of ABCAI and ABCG1, which may be helpful to suppress the formation of foam cells.

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.

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.

Study of vascular smooth muscle cell calcification induced by hyperphosphate and intervented by phosphonoformic acid

Objective： To evaluate the effects of different concentrations of phosphate on calcium deposition and osteocalcin level in cultured bovine aortic smooth muscle cell, investigate the mechanism of hyperphosphatemia to evoke calcification of vascular smooth muscle cell and observe the effects of phosphonoformic acid（PFA） in different concentrations on vascular calcification. Methods： The bovine aortic smooth muscle cells （BASMC） were cultured.Calcium deposition and the expression of osteocalcin of BASMC in different concentrations of phosphate （1.5 mmol/L and 2.0 mmol/L） and PFA were determined by o-cresolphthalein complexone and radioimmunity methods, respectively. Osteocalcin mRNA expressions were determined by RT-PCR. Results： After six or nine days of BASMC cultured, the calcium deposition in Pi 2.0 mmol/L group was more than that in Pi 1.5 mmol/L group[（77.187 ± 11.692） lag/（mg · protein） vs（25.768 ± 1.750）lag/（mg · protein）, P 〈 0.01 and（125.399 ± 16.677）lag/（mg · protein） vs（29.046 ± 2.635）lag/（mg · protein）, P 〈 0.01 respectively]. The calcium deposition was dependent on time and dosage of phosphate treatment. After 72 h culture the osteocalcin in Pi 2.0 mmol/L group was more than that in Pi 1.5 mmol/L grouplin supematant,（1.503 ± 10^-2 ± 2.601 × 10^-3）ng/（ lag o protein） vs（2.981 × 10-3 ± 8.382 × 10-34）ng/（ lag · protein）, P 〈 0.001], the same was found in osteocalcin mRNA expression[OC/GAPDH, （1.906 ± 0.132） vs（0.748 ± 0.037）, P〈 0.001]. Compared to Pi 1.5mmol/L group,bovine smooth muscle cells（BSMC） cultured in media containing Pi 2.0 mmol/L phosphate levels increased calcium deposition[On day 6,（77.187 ± 11.692） la g/（mg · protein） vs （25.768 ±1.750） la g/（mg · protein）, P 〈 0.001]. Elevated phosphate treatment of BSMCs also enhanced the expression of the osteoblastic differentiation marker osteocalcin[On day 3, Pi 2.0 mmol/L group vs Pi 1.5mmol/L group,（1.503 × 10^-2 ± 2.601 × 10^-3 ）ng/（ lag · protein） vs（2.981× 10^-3 ± 8.382 × 10^-4）ng/（ μg · protein）, P 〈 0.001]. PFA decreased ciacium deposition and osteocalcin expression statistically[Pi 2.0 mmol/L±PFA1.0 mmol/L group vs Pi 2.0mmol/L group, ciacium deposition, （37.729 ± 5.899） lμg/（mg · protein） vs （77.187 ± 11.692）μg/（mg ·protein）, P 〈 0.001]; Osteocalcin in supernatant, （4.529 ± 10^-3 ± 1.250 × 10^-3）ng/（ μ g · protein） vs（1.503 × 10^-2 ± 2.601 × 10^-3） ng/（ μg · protein）, P〈 0.001; osteocalcin mRNA expression, OC/GAPDH, （0.642 ± 0.092） v s （1.89 ± 0.165）, P 〈 0.01]. Conclusion： Hyperphosphate may directly promote calcium deposition and the osteocalcin expression of B ASMCs. It may be a new explanation for the phenomenon of vascular calcification in hyperphosphatemic conditions. Hyperphosphatemia is an independent factor to stimulate vascular calcification. PFA can inhibit calcium deposition and osteocalcin expression induced by elevated phosphate.PFA may be a new medicine to treat vascular calcification induced by elevated phosphate.

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.

Aged Garlic Extract and One of the Constituent, (+)-(2S,3R)-Dehydrodiconiferyl Alcohol, Inhibits Alkaline Phosphatase Activity Induced by Inflammation Factors in Human Vascular Smooth Muscle Cells

Previous clinical study showed that aged garlic extract (AGE) has a preventive effect of vascular calcification in patients with coronary artery diseases. It has been reported that vascular smooth muscle cells (VSMC) and inflammatory cells including macrophages and lymphocytes migrate to sub-intimal region where atherosclerotic plaques are formed, and VSMC can differentiate into osteoblast-like cells, which are represented by the induction of alkaline phosphatase (ALP). We found that primary human coronary artery smooth muscle cells (HCASMC) showed the increased ALP activity, when cultured in the medium containing ascorbic acid, β-glycerophosphate, dexamethasone (IM), and supplemented with conditioned medium from macrophages (MCM). Then we tested the effect of AGE subdivided fractions and several compounds found in AGE, and then found that ((+)-(2S,3R)-Dehydrodiconiferyl alcohol, a dilignol compound existed in hydrophobic fraction of AGE, inhibited ALP activity in HCASMC.

The crosstalk between endothelial cells and vascular smooth muscle cells during low shear stress:a proteomic-based approach

Instruction Shear stress,caused by the parallel frictional drag force of blood flow,is a biomechanical force which plays an important role in the control of blood vessels growth and functions [1]. Clinical researches had found out that atherosclerotic le-

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.