Barringhaus Kurt G, Matsumura Martin E
Cardiology Division, University of Massachusetts Medical Center, Worcester, Massachusetts;
Exp Clin Cardiol. 2007 Fall;12(3):119-24.
There is emerging evidence that the ubiquitin-proteasome system plays a role in vascular proliferative disorders such as restenosis after percutaneous coronary interventions. The present study examined the effect of proteasome inhibition on cultured vascular smooth muscle cell (VSMC) growth and migration, as well as on vascular lesion formation, following balloon arterial injury in the rat.
The effect of the proteasome inhibitor clasto-lactacystin beta-lactone (lactacystin) on cultured VSMC proliferation was assessed using cell proliferation assays and immunohistochemical assessment of S-phase entry. To test the effect of proteasome inhibition on lesion formation and to confirm the role of p21(Cip1/Waf1) (p21) in this effect in vivo, carotid injury was performed on anesthetized male Sprague-Dawley rats, followed by local treatment with either lactacystin or vehicle.
Treatment of VSMCs with the proteasome inhibitor lactacystin resulted in a 60% and 80% decrease in cell number versus controls at day 3 and day 5 after treatment, respectively. This effect was accompanied by an 86% decrease in S-phase entry and an increased level of the cyclin-dependent kinase inhibitor p21. Additionally, lactacystin significantly inhibited VSMC migration in a modified Boyden chamber assay. Lactacystin resulted in a 59% reduction of neointimal formation at 14 days following balloon injury. This effect was associated with an early increase in p21 protein in the arterial wall.
Inhibition of the ubiquitin-proteasome system resulted in the attenuation of VSMC growth both in cultured cells and in an animal model of vascular injury, possibly via a mechanism involving upregulation of the p21 cyclin-dependent kinase inhibitor. These data provide support for a role of the proteasome in the vascular response to injury, and suggest an important role for p21 and attenuation of cellular migration in the mechanism of this effect.
越来越多的证据表明，泛素-蛋白酶体系统在血管增殖性疾病中发挥作用，如经皮冠状动脉介入术后再狭窄。本研究检测了蛋白酶体抑制对大鼠球囊动脉损伤后培养的血管平滑肌细胞（VSMC）生长和迁移以及血管病变形成的影响。
使用细胞增殖试验和S期进入的免疫组织化学评估，评估蛋白酶体抑制剂clasto-乳胞素β-内酯（乳胞素）对培养的VSMC增殖的影响。为了测试蛋白酶体抑制对病变形成的影响，并在体内证实p21（Cip1/Waf1）（p21）在该效应中的作用，对麻醉的雄性Sprague-Dawley大鼠进行颈动脉损伤，随后局部给予乳胞素或赋形剂。
用蛋白酶体抑制剂乳胞素处理VSMC后，在处理后第3天和第5天，细胞数量分别比对照减少60%和80%。这种效应伴随着S期进入减少86%和细胞周期蛋白依赖性激酶抑制剂p21水平升高。此外，在改良的Boyden小室试验中，乳胞素显著抑制VSMC迁移。乳胞素导致球囊损伤后14天新生内膜形成减少59%。这种效应与动脉壁中p21蛋白的早期增加有关。
泛素-蛋白酶体系统的抑制导致培养细胞和血管损伤动物模型中VSMC生长的减弱，可能是通过一种涉及上调p21细胞周期蛋白依赖性激酶抑制剂的机制。这些数据支持蛋白酶体在血管损伤反应中的作用，并表明p21和细胞迁移减弱在该效应机制中起重要作用。
