Hassan Ghada S, Mukherjee Shankar, Nagajyothi Fnu, Weiss Louis M, Petkova Stefka B, de Almeida Cecilia J, Huang Huan, Desruisseaux Mahalia S, Bouzahzah Boumediene, Pestell Richard G, Albanese Chris, Christ George J, Lisanti Michael P, Tanowitz Herbert B
Department of Pathology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
Infect Immun. 2006 Jan;74(1):152-9. doi: 10.1128/IAI.74.1.152-159.2006.
Trypanosoma cruzi infection causes cardiomyopathy and vasculopathy. Previous studies have demonstrated that infection of human umbilical vein endothelial and smooth muscle cells resulted in activation of extracellular signal-regulated kinase (ERK). In the present study, smooth muscle cells were infected with trypomastigotes, and immunoblot analysis revealed an increase in the expression of cyclin D1 and proliferating cell nuclear antigen (PCNA), important mediators of smooth muscle cell proliferation. Interestingly, after infection, the expression of caveolin-1 was reduced in both human umbilical vein endothelial cells and smooth muscle cells. Immunoblot and immunohistochemical analyses of lysates of carotid arteries obtained from infected mice revealed increased expression of PCNA, cyclin D1, its substrate, phospho-Rb (Ser780), and phospho-ERK1/2. The expression of the cyclin-dependent kinase inhibitor p21(Cip1/Waf1), caveolin-1, and caveolin-3 was reduced in carotid arteries obtained from infected mice. There was an increase in the abundance of pre-pro-endothelin-1 mRNA in the carotid artery and aorta from infected mice. The ET(A) receptor was also elevated in infected arteries. ERK activates endothelin-1, which in turn exerts positive feedback activating ERK, and cyclin D1 is a downstream target of both endothelin-1 and ERK. There was significant incorporation of bromodeoxyuridine into smooth muscle cell DNA when treatment was with conditioned medium obtained from infected endothelial cells. Taken together, these data suggest that T. cruzi infection stimulates smooth muscle cell proliferation and is likely a result of the upregulation of the ERK-cyclin D1-endothelin-1 pathway.
克氏锥虫感染可导致心肌病和血管病变。先前的研究表明，人类脐静脉内皮细胞和平滑肌细胞感染后会导致细胞外信号调节激酶（ERK）激活。在本研究中，用锥鞭毛体感染平滑肌细胞，免疫印迹分析显示细胞周期蛋白D1和增殖细胞核抗原（PCNA）的表达增加，这二者是平滑肌细胞增殖的重要介质。有趣的是，感染后，人类脐静脉内皮细胞和平滑肌细胞中的小窝蛋白-1表达均降低。对感染小鼠的颈动脉裂解物进行免疫印迹和免疫组织化学分析显示，PCNA、细胞周期蛋白D1、其底物磷酸化Rb（Ser780）和磷酸化ERK1/2的表达增加。在感染小鼠的颈动脉中，细胞周期蛋白依赖性激酶抑制剂p21（Cip1/Waf1）、小窝蛋白-1和小窝蛋白-3的表达降低。感染小鼠的颈动脉和主动脉中前内皮素-1 mRNA的丰度增加。感染动脉中的ET(A)受体也升高。ERK激活内皮素-1，内皮素-1又发挥正反馈作用激活ERK，细胞周期蛋白D1是内皮素-1和ERK的下游靶点。当用从感染的内皮细胞获得的条件培养基处理时，溴脱氧尿苷显著掺入平滑肌细胞DNA中。综上所述，这些数据表明克氏锥虫感染刺激平滑肌细胞增殖，这可能是ERK-细胞周期蛋白D1-内皮素-1途径上调的结果。
