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.

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.

EXPRESSION OF CALCITONING GENE-RELATED PEPTIDE IN VASCULAR SMOOTH MUSCLE CELLS BY RETROVIRUS-MEDIATED GENE TRANSFER

Background:The contemporary treatment of coronary athero-occlusive disease bypercutaneous transluminal coronary angioplasty is hampered by maladaptive woundhealing,resulting in significant failure rates.Morbid sequelae include smooth musclecell(SMC)hyperplesia and restenosis due to vascular neointimal formation.Calcitoningene-related peptide(CGRP)has been proposed as a potential therapeutic neuopeptide forintimal hyperplastic vascular disease.Methods and Results:In this study,we investigated CGRP gene expression in culturedrat thoracic arterial smooth muscle cells(SMCs)A replication-defective,recombinantretrovirus containing human α-CGRP cDNA(termed pRCGRP)was constructed and usedto infect SMCs in culture.Following selection with G418,cells traneduced by pRCGRPwere found to express CGRP and stable transfer of CGRP in SMCs was achieved withretroviral vector.CGRP gene expression was observed only when cultured SMCs weretransduced with vectors containing the CGRP cDNA No evidence of similar geneexpression was observed in nontranfected or empty vector transfected SMCs CGRPexpressed in the transduced SMCs was secreted into culture medium and was detected byradioimmunoassay(RIA).The highest level of CGRP gene product reached 18.2±0.6pM,whereas that of normal and control group were undectable.Conclusions:The fact that a recombinant gene can be readily inserted and efficientlyexpressed in vascular smooth muscle cells suggests that CGRP gene may be served as apromising candidate gene for gene therapy in atharosclerosis and restenosis.Retroviralmediated CGRP gene transfer may he used to treat atherosclerosis and restenosis.

Increased expression of osteoprotegerin in vascular smooth muscle cells from spontaneously hypertensive rats

Background Osteoprotegerin (OPG) is a secreted protein of the tumor necrosis factor receptor family, which regulates bone mass by inhibiting osteoclast differentiation and activation. Although OPG is expressed ubiquitously and abundantly in many tissues and cell types including vascular cells, the role of OPG in other tissues is unknown.Our previous studies demonstrated that OPG was highly expressed in vascular smooth muscle cells (VSMC) and upregulated during vascular lesion formation. Methods and Results We documented, by Northern blot analysis,that the expression of OPG was more prevalent in the aorta and cultured VSMC from spontaneously hypertensive rats (SI-IR) compared to Wistar-Kyoto rats (WKY). In addition, we found that the expression of Angiotensin II (Ang II)type I receptor (AT1R) in SHR VSMC was at significantly increased levels than in WKY VSMC. Furthermore, Ang II potently induced the expression of OPG in VSMC in a time- and dose-dependent manner through the AT1R signaling pathway. Conclusions OPG expression was substantially greater in SHR VSMC, suggesting that OPG may be an important determinant of vascular remodeling in SHR.

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 pcD-NA3 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 pGEMSZf ( + ) 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.

Down-regulation of the gax gene in smooth muscle cells of the splenic vein of portal hypertension patients

BACKGROUND: The expression of gax, an anti-prolifera-tive homeobox gene, is rapidly down-regulated in vascular smooth muscle cells (VSMCs) following arterial injury. Whether the down-regulation of gax is involved in modulating the proliferation of smooth muscle cells of the splenic vein in patients with portal hypertension has not yet been elucidated. The aim of this study was to investigate the expression of the mRNA of the gax gene in smooth muscle cells of the splenic vein in patients with portal hypertension. METHODS: Reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect the expression of gax mRNA and immunohistochemistry staining was performed to demonstrate the expression of PCNA protein in the splenic veins of 28 patients with portal hypertension and those of 12 normal controls. This study was approved by the Institutional Ethics Committee and informed consent was obtained from all participants. RESULTS: RT-PCR showed that the expression of gax mRNA was PCNA-positive and negative in the splenic vein of patients with portal hypertension (1.08 ± 0.04 and 1.39 ± 0.27, respectively). There was a significant difference in the 28 patients compared with the 12 normal controls ( P < 0.01). The relative expression of PCNA protein in the vascular tissues was significantly higher in the experimental group than in the control group. CONCLUSIONS: Down-regulation of gax mRNA and the overexpression of PCNA protein were seen in smooth muscle cells of the splenic vein in patients with portal hypertension, regulating the proliferation, migration and phenoty-pic change and resulting in remodelling of the splenic vein, which may play an important role in the pathogenesis and maintenance of portal hypertension.

Vascular smooth muscle cell differentiation－2010

Vascular smooth muscle cells have attracted considerable interest as a model for a flexible program of gene expression.This cell type arises throughout the embryo body plan via poorly understood signaling cascades that direct the expression of transcription factors and microRNAs which,in turn,orchestrate the activation of contractile genes collectively defining this cell lineage.The discovery of myocardin and its close association with serum response factor has represented a major break-through for the molecular understanding of vascular smooth muscle cell differentiation.Retinoids have been shown to improve the outcome of vessel wall remodeling following injury and have provided further insights into the molecular circuitry that defines the vascular smooth muscle cell phenotype.This review summarizes the progress to date in each of these areas of vascular smooth muscle cell biology.

Inhibition of vascular smooth muscle cell proliferation by in troduction of retinoblastoma gene via a recombinant adenovirus vector

This study was supported in part by grant from National Natural Science Foundation of China (No. 39570775). Objective To investigate the vascular smooth muscle cell (SMC) growth suppression by recombinant adenovirus vector expressing a retinoblastoma (Rb) protein and to explore a gene therapy approach for vascular proliferative disorders including atherosclerosis and artery restenosis. Methods A replication deficient adenovirus vector encoding a wild type Rb and AdCMVRb, was constructed and transfected into cultured rabbit aortic SMC. The efficiency of gene transfection and expression was detected by immunochemical staining and polymerase chain reaction. The role of Rb in regulating vascular SMC proliferation was observed by cell counting, thymidine incorporation, and flow cytometry. Results Wild type Rb gene transfected effectively into the cultured SMC with AdCMVRb can suppress growth factor stimulated cell proliferation through regulation of DNA synthesis and cell cycle progression. Conclusion The results demonstrate the potential of adenovirus mediated Rb gene therapy for atherosclerosis and artery restenosis after balloon angioplasty.

ADENOVIRUS MEDIATED GENE TRANSFER OF VASCULAR SMOOTH MUSCLE CELLS AND ENDOTHELIAL CELLS IN VITRO

Introducing foreign gene(s) into vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) is the pre-require-ment of gene therapy for cardiovascular diseases. We have explored the use of adenoviral vectors (Adv-CMV / LacZ) to transfer LacZ gene into cultured VSMCs and ECs. Our results demonstrated that adenoviral vectors transfered foreign gene into VSMCs and ECs high-efficiently with dose-dependent response pattern. The frequencies of transfection reached 100% at the viral titer of 109 pfu / ml. Comparing the sensitivities of VSMCs and ECs to adenoviral vectors, we found that ECs were more sensitive than VSMCs, of which the frequencies of transfection in ECs reached 80% while in VSMCs only 40% for 8 hrs after transfection. In addition, the transfection of ECs and VSMCs with adenoviral vectors was partly blocked by monoclonal antibodies to Fiber and Core protein of the adenoviral capsid, but not by monoclonal antibody to Hcxon protein. It is suggested transfection of ECs and VSMCs with adenovirus vectors is mediated by Fiber or Core protein of adenoviral capsid proteins.

SHORT COMMUNICATIONS Comparison of inositol phosphates formation and gene expression of Gq alpha subunit in cultured aortic smooth muscle cells from spontaneously hypertensive and Wistar Kyoto rats

Abstract Objecitve To explore whether phosphoinositide specific phospholipase C (PLC) activation via G protein in vascular smooth muscle cells (VSMCs) is altered in spontaneously hypertensive rats (SHR). Methods The VSMCs derived from aortae of SHR and Wistar Kyoto (WKY) rats were loaded for 48 hours with myo inositol. Inositol phosphate release was initiated by the addition of 10 5 mol/L norepinephrine in intact cells or by guanosine 5' 0 (3 thio tri sphosphate) (GTP gamma S) in permeabilized cells. In the meantime, growth arrested VSMCs were stimulated by 10% calf serum for 0, 30, 45, or 60 min, then gene expressions of Gq alpha subunit (G alph a q) were observed. Results There were no significant differences in inositol 1, 4,5 triphosphate (IP 3) level and expression of G alpha q mRNA between quiescent VSMCs from SHR and that from WKY. When stimulated by norepinephrine, IP 3 production increased transiently with a peak level at 10 s in VSMCs from WKY, and a rapid biphasic IP 3 response, which was significantly higher than that of WKY, in VSMCs from SHR had been observed. G proteins activated by GTP gamma S significantly raised IP 3 production in VSMCs from SHR compared to WKY (SHR vs WKY: 234.8%±29.2% vs 142.4%±12.0% of basal IP 3, P<0.05). In addition, the serum effect showed an significant increase in expression of G alpha q mRNA in VSMCs from SHR. Conclusions The hereditary factors are not the only variable regulating IP 3 metabolism and G alpha q gene expression. Influences of multi environmental factors such as vasoactive compounds, together with genetic predisposition, palys an important role in the highly sensitive response of IP 3 production and G alpha q gene over expression in SHR.

Killing effect of coexpressing cytosine deaminase and thymidine kinase on rat vascular smooth muscle cells

Background Vascular smooth muscle cell (VSMC) proliferation following arterial injury plays a critical role in a variety of vascular proliferative disorders, such as atherosclerosis and restenosis after balloon angioplasty. Herpes simplex virus-thymidine kinase (HSV-TK)/ganciclovir (GCV) and E.coli cytosine deaminase (CD)/5-fluorocytosine (5-Fc) suicide gene systems have been successfully employed in cardiovascular gene therapy, respectively. We reasoned that coexpression of both HSV-TK with CD suicide genes would lead to increased cell killing. To test this imagine, the adenoviral vectors expressing TK and/or CD genes were developed and tested on vascular smooth muscle cells. Methods Adenoviral vectors, including Ad-EF1α-CD-cytomegolovirus (CMV)-TK coexpressing both CD and TK double suicide genes, Ad-EF1α-CD and Ad-CMV-TK expressing CD and TK respectively, and control vector Ad-CMV-LacZ, were constructed and prepared with homologous recombination in RecA+E.coli cells. Integration and expression of CD and/or TK gene were identified by PCR and Western blot. Primary cultured VSMCs were infected at a multiplicity of infection (MOI) of 20 with exposure to their matching prodrugs 5-Fc and GCV. Cell mortality was measured by methyl thiazolyl tetrazolium (MTT) assays. Flow cytometry analysis was used to detect cell death. Apoptotic cells were analyzed using Hoechst 33342 fluorescence dye as a DNA probe. Genomic DNA cleavage of apoptotic VSMCs was tested by agarose gel electrophoresis. Results Recombinant adenovirus expressing CD and/or TK suicide genes were successfully constructed. Both single and double suicide genes could be integrated into adenoviral genome and expressed. Cytotoxic effects of Ad-EF1α-CD-CMV-TK double suicide genes combined with 5-Fc and GCV were higher than those of Ad-CMV-TK and Ad-EF1α-CD single gene groups. The rate of cell survival was only (9±3)% in the Ad-EF1α-CD-CMV-TK group, but (37±3)% in the Ad-CMV-TK and (46±4)% in the Ad-EF1α-CD groups (P<0.05). Flow cytometry analysis indicated that the killing mechanisms of the groups were different. Necrosis and apoptosis were involved in the mechanism of the double gene group. Based on the DNA stainability with Hoechst 33342, the apoptotic rates of VSMCs in the Ad-EF1α-CD-CMV-TK [(11.0±2.1)%] and Ad-CMV-TK [(12.0±2.2)%] groups were higher than those in Ad-CMV-LacZ [(1.2±0.11)%] and Ad-EF1α-CD [(5.0±1.8)%] groups (P<0.05, respctively). DNA smear could be observed in both Ad-CMV-TK and Ad-EF1α-CD-CMV-TK groups after administration of prodrugs. Conclusions The killing effect on rat VSMCs mediated by adenoviral CD/TK double suicide genes is superior to that of single suicide gene. The killing mechanism of recombinant adenovirus coexpressing CD/TK double suicide genes is mainly through cytotoxic effect and apoptosis.

Endothelin-1, an important mitogen of smooth muscle cells of spontaneously hypertensive rats

OBJECTIVE: To study the features of vascular smooth muscle cell (VSMC) proliferation induced by endothelin-1 (ET-1). METHODS: VSMCs of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats were cultured and treated with ET-1. Basic fibroblast growth factor (bFGF) gene expression was measured using both Northern blot and an enzyme-linked immunoassay. RESULTS: ET-1 resulted in an increase in bFGF transcripts at 8 - 24 h; bFGF levels were significantly higher in VSMCs treated with ET-1 than in those not treated. However, VSMCs growth responses in SHR and WKY were different. Smooth muscle cells of SHR were hyper-responsive to ET-1. Maximal bFGF mRNA levels were elevated 3.5-fold at 4 h of stimulation in WKY and 8-fold at 8h in SHR4. Moreover, the proliferation of VSMCs induced by ET-1 was inhibited by antisense phosphorothioate oligodeoxynucleotides (10 micromol/L AS-bFGF) but not sense bFGF oligomers at the same concentrations, being reduced by 80% in SHR and 40% in WKY vs control, respectively. Furthermore, the effect of AS-bFGF oligomers on SHR SMC proliferation is significantly greater than on WKY SMC proliferation. CONCLUSION: ET-1 may be required for exaggerated vascular growth responses in SHR and bFGF may be involved.

From contraction to gene expression:nanojunctions of the sarco/endoplasmic reticulum deliver site-and function-specific calcium signals

Calcium signals determine, for example, smooth muscle contraction and changes in gene expression. How calcium signals select for these processes is enigmatic. We build on the "panjunctional sarcoplasmic reticulum" hypothesis, describing our view that different calcium pumps and release channels, with different kinetics and affinities for calcium, are strategically positioned within nanojunctions of the SR and help demarcate their respective cytoplasmic nanodomains. SERCA2 b and Ry R1 are preferentially targeted to the sarcoplasmic reticulum(SR) proximal to the plasma membrane(PM), i.e., to the superficial buffer barrier formed by PM-SR nanojunctions, and support vasodilation. In marked contrast, SERCA2 a may be entirely restricted to the deep, perinuclear SR and may supply calcium to this sub-compartment in support of vasoconstriction. Ry R3 is also preferentially targeted to the perinuclear SR, where its clusters associate with lysosome-SR nanojunctions. The distribution of Ry R2 is more widespread and extends from this region to the wider cell. Therefore, perinuclear Ry R3 s most likely support the initiation of global calcium waves at L-SR junctions, which subsequently propagate by calcium-induced calcium release via Ry R2 in order to elicit contraction. Data also suggest that unique SERCA and Ry R are preferentially targeted to invaginations of the nuclear membrane. Site- and function-specific calcium signals may thus arise to modulate stimulus-response coupling and transcriptional cascades.

Basic fibroblast growth factor gene transfection in repair of internal carotid artery aneurysm wall

Surgery or interventional therapy has some risks in the treatment of cerebral aneurysm. We established an internal carotid artery aneurysm model by dripping elastase in the crotch of the right internal and external carotid arteries of New Zealand rabbits. Following model induction, lentivirus carrying basic fibroblast growth factor was injected through the ear vein. We found that the longer the action time of the lentivirus, the smaller the aneurysm volume. Moreover, platelet-derived growth factor expression in the aneurysm increased, but smooth muscle 22 alpha and hypertension-related gene 1 mRNA expression decreased. At 1,2, 3, and 4 weeks following model establishment, following 1 week of injection of lentivirus carrying basic fibroblast growth factor, the later the intervention time, the more severe the blood vessel damage, and the bigger the aneurysm volume, the lower the smooth muscle 22 aJpha and hypertension-related gene ~ mRNA expression. Simultaneously, platelet-derived growth factor expression decreased. These data suggest that recombinant lentivirus carrying basic fibroblast growth factor can repair damaged cells in the aneurysmal wall and inhibit aneurysm dynamic growth, and that the effect is dependent on therapeutic duration.

Construction and Identification of Recombinant Adenovirus Vector Containing the hVEGF_(165) Gene

To construct the recombinant adenovirus vector containing the cDNA for human vascular endothelial growth factor (hVEGF 165 ), the cDNA for hVEGF 165 was subcloned into pACCMV·pLpA. Subsequently, this recombinant pACCMV·hVEGF was co transfected into 293 cells together with pJM17 to obtain the replication deficient recombinant adenovirus containing hVEGF gene-AdCMV·hVEGF. The VEGF gene expression was detected by using RT PCR and Western blot in rabbit aorta vascular smooth muscle cells (VSMC) infected with AdCMV· hVEGF. Cultured human umbilical vein endothelial cells (HUVEC) were incubated with the conditioned medium (CM) from above mentioned VSMC infected with AdCMV·hVEGF to observe the effect of VEGF on proliferation of HUVEC. 48 h after the infection with AdCMV·hVEGF, VSMC demonstrated VEGF expression, and the expressed VEGF could stimulate the proliferation of HUVEC in vitro . Successfully prepared AdCMV·hVEGF 165 could express biologically active VEGF in infected VSMC, and stimulate proliferation of HUVEC.

Screening Rat Hypertension-Related Genes By Differential Display

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Hcy促血管平滑肌细胞增殖迁移相关的miRNAs筛选研究

目的明确同型半胱氨酸(homocysteine,Hcy)对人源血管平滑肌细胞(vascular smooth muscle cell,VSMC)增殖迁移的影响以及分析Hcy干预下VSMC增殖迁移相关差异miRNAs,为探讨Hcy促VSMC增殖迁移的分子机制提供依据。方法体外培养VSMC,分为Control组和100μmol·L^(-1) Hcy组。采用CCK-8法测量VSMC的增殖活性;采用划痕实验分析VSMC在0 h和48 h的迁移情况。高通量测序分析各组VSMC中差异化表达的miRNAs,采用miRanda和TargetScan软件进行靶基因预测,使用BLAST软件将预测靶基因序列与GO和KEGG数据库比对,分析靶基因的功能,获得与VSMC增殖和迁移相关的靶基因信息。通过RT-qPCR对其中表达上调的miRNAs进行验证。结果Hcy干预能增加VSMC的增殖活力(P<0.01),且VSMC的划痕面积减少(P<0.01)。两组细胞共检测到576个miRNAs,其中已知miRNAs 404个,新预测miRNAs 172个。与Control组相比,Hcy组存在88个差异表达的miRNAs,其中表达上调的20个,表达下调的68个。与VSMC增殖和迁移相关的miRNAs有20个,表达上调的包括miRNA39、miRNA206和miRNA212-5p,表达下调的包括miRNA35等17个。RT-qPCR结果显示,Hcy组miRNA212-5p的表达上调(P<0.05)。结论Hcy致VSMC增殖迁移过程中存在差异表达的miRNAs,miRNA212-5p可能参与了Hcy对VSMC的作用。