人激肽释放酶基因转移对大鼠血管平滑肌细胞增殖的影响

目的 探讨重组腺病毒介导的人激肽释放酶(human tissue kallikrein 1,hKLK1)基因转移对血小板源性生长因子-BB(platelet derived growth factor-BB,PDGF-BB)诱导下的自发性高血压大鼠(SHR)血管平滑肌细胞(vascular smooth muscle cells,VSMCSHR)增殖的影响及其机制.方法 自行构建重组腺病毒载体,携带目的 基因hKLK1和标志基因强绿色荧光蛋白.细胞计数法和四甲基偶氮唑盐(MTF)比色法检测细胞增殖,流式细胞仪检测细胞生长周期.蛋白免疫印迹法测定细胞周期素依赖性激酶抑制蛋白p27Kip1、p21Cip1的表达.RT-PCR法测定缓激肽B1受体、B2受体的mRNA表达.结果 (1)hKLK1基因转移呈感染复数依赖性(20～100 M0I)抑制PDGF-BB诱导的VSMCSHR生长,100 MOI时抑制率为39.3%;呈时间依赖性抑制VSMCSHR生长,第5天时达高峰,抑制率为35.2%.(2)hKLK1基因转移可显著抑制PDGF-BB诱导的VSMCSHR增殖,峰值抑制率为30.2%(P＜0.01);细胞周期阻滞于G0/G1期的VSMCSHR明显增多,最大阻滞率为36.4%(P＜0.001).(3)hKLK1基因转移明显上调PDGF-BB诱导VSMCSHR的p27Kip1、p21Cip1表达,而缓激肽B2受体特异性阻断剂Hoe140明显降低p27Kip1、p21Cip1表达.(4)PDGF-BB诱导VSMCSHR的缓激肽B2受体mRNA表达明显增加(P＜0.001),且Hoe140可明显降低其表达(P＜0.01).结论 hKLK1基因转移可抑制PDGF-BB诱导的VSMCSHR增殖,可上调缓激肽B2受体和细胞周期素依赖性激酶抑制蛋白p27Kip1、p21Cip1表达.

Effects of human tissue kallikerin gene delivery on the proliferation of vascular smooth muscle cells

Objective Tissue kallikrein cleaves kininogen substrate to produce vasoactive kinin peptides that have been implicated in the proliferation of vascular smooth muscle cells. We investigated the effects of adenovirus-mediated human tissue kallikerin(Ad-hKLK1)gene delivery on the proliferation of vascular smooth muscle cells of SHR(VSMCsSHR)induced by platelet derived growth factor-BB(PDGF-BB). Methods Primary VSMCsSHR were isolated and cultured from thoracic aorta of male SHR. The VSMCsSHR proliferation induced by PDGF-BB was accessed by cell counting and methyl thiazolyl tetrazoliuin(MTT). Western blot was used to determine the protein expression of hKLK1, the cycle-independent kinase inhibitors p27Kip1 and p21Cip1 . The mRNA expressions of bradykinin B1 receptor and B2 receptor were detected by RT-PCR in VSMCsSHR. Results Proliferation of VSMCsSHR induced by PDGF-BB was significantly inhibited post transfection of Ad-hKLK1(20 - 100 MOI)in a MOI-dependent manner. The peak inhibition titer of Ad-hKLK1 was 100 MOI with peak inhibition rate of 39.3%(cell counting, n = 3,P ＜0.01), 30.2%(MTT, n-3 ,P ＜ 0.01)and 36.4%(peak stunning rate of cell-cycle in phase G0/G1). The inhibitory effects of proliferation and cell-cycle caused by hKLK1 gene delivery could be abolished by Hoe140, a bradykinin B2 receptor antagonist. The protein expression of p27Kip1 and p21Cip1 increased significantly after the hKLK1 gene delivery, whereas Hoe140 nearly completely blocked these effects(n = 3,P ＜0.001 ,respectively). PDGF-BB also significantly upregulated the mRNA expression of B2 receptor but not B1 receptor in VSMCsSHR. Conclusion The hKLK1 gene delivery could inhibit PDGF-BB induced proliferation in VSMCsSHR through Bradykinin B2 receptor and up-regulate expression of p27Kip1 and p21Cip1.