Molecular Mechanisms in Trypanosoma cruzi Cardiomyopathy in AIDS

描述（由申请人提供）：恰加斯病是由原生动物寄生虫克氏锥虫引起的，现在被认为是一种新出现的与艾滋病毒/艾滋病相关的机会性感染。免疫抑制后，休眠生物体重新激活，导致心肌炎和坏死性脑炎。由于接受HAART治疗的艾滋病毒感染者可存活多年，因此随着其免疫状态的起起落落，可能会反复出现重新激活的情况。因此，进行性心肌炎、心血管重构和慢性心肌病可能会以更快的方式发展。在这个应用中，我们将心室重构定义为心肌损伤后结构和功能的变化以及特征性的分子变化。这些变化是炎症和/或坏死的结果。克氏锥虫感染心肌可导致扩张性心肌病。我们的总体目标是研究一些重要的信号通路，这些信号通路与克氏锥虫感染引起的心脏重塑有关。我们的研究清楚地表明，克氏锥虫诱导的ERK激活可以调节细胞周期蛋白的表达和/或活性，而细胞周期蛋白是细胞增殖和分化的介质。细胞周期蛋白负责心血管系统的重塑。因此，细胞周期蛋白在受感染的培养细胞和共培养系统中的表达动力学。由于我们已经证明T. cruzi诱导细胞周期蛋白D1的表达，我们将利用瞬时转染/启动子试验确定心脏成纤维细胞中细胞周期蛋白D1启动子激活调控的分子机制。我们计划确定克氏锥虫感染对小鼠慢性心脏病模型中细胞周期蛋白的影响。急性克氏锥虫感染时，心肌中ERK、转录因子AP-1和NF-kB被激活，细胞周期蛋白d1的表达增加。因此，在恰加斯病小鼠模型中，将确定克鲁兹锥虫感染小鼠心肌细胞中细胞周期调节蛋白的表达动力学，并将其与心肌病的进展相关联。心肌中这些蛋白改变的机制将通过多种技术进行研究，包括免疫复合物测定和细胞增殖实验。我们将利用小鼠模型来研究细胞周期蛋白D1在心血管重塑中的作用，包括细胞周期蛋白D1缺失小鼠和NF-r。d3和ET-1被选择性地从心肌细胞中删除。这些研究将有助于更好地理解恰加斯型心肌病的心脏重塑，恰加斯型心肌病是艾滋病中出现的一种机会性感染。此外，它还将提供辅助治疗的潜在靶点。

DESCRIPTION (provided by applicant): Chagas' disease is caused by the protozoan parasite T. cruzi and is now recognized as an emerging HIV/AIDS-related, opportunistic infection. Subsequent to immunosuppression there is reactivation of dormant organisms leading to myocarditis and necrotizing encephalitis. Since HIV-infected patients receiving HAART live for many years there is the likelihood that there will be repeated episodes of reactivation as their immune status waxes and wanes. Hence, progressive myocarditis and cardiovascular remodeling and chronic cardiomyopathy will likely develop in a more rapid fashion. In this application we have defined ventricular remodeling as changes in structure and function following myocardial damage together with characteristic molecular changes. These changes are the result of inflammation and/or necrosis. T. cruzi infection of the myocardium results in a dilated cardiomyopathy. Our overall objective is to examine some of the important signaling pathways involved in cardiac remodeling as a consequence of the T. cruzi infection. We plan to examine the consequences of T. cruzi-infection on cyclins in vitro, Our investigations clearly indicate that T. cruzi-induced ERK activation modulates the expression and/or activity of cyclins, which function as mediators of cellular proliferation and differentiation. Cyclins are responsible for remodeling in the cardiovascular system. Therefore, the kinetics of the expression of cyclins in infected cultured cells and co-culture systems. Since we have demonstrated that T. cruzi induces expression of cyclin D1, we will determine the molecular mechanisms involved in regulation of cyclin D 1 promoter activation in cardiac fibroblasts employing transient transfection/promoter assays. We plan to determine the consequence of T. cruzi infection on cyclins in mouse models of chagasic heart disease on. During acute T. cruzi infection there is activation of ERK, transcription factors AP-1 and NF-kB and increased expression of cyclin D 1 in the myocardium. Therefore, in the mouse model of Chagas' disease the kinetics of expression of cell cycle regulatory proteins in the cells of the myocardium of T. cruzi-infected mice will be determined and correlated with progression of cardiomyopathy. The mechanisms underlying the alterations in these proteins in the myocardium will be investigated by a variety of techniques including immune complex assays and cell proliferation experiments. The contribution of cyclin D 1 in cardiovascular remodeling will be investigated utilizing mouse models including cyclin D1 null mice and mice in which NF-r.d3 and ET-1 have been selectively deleted from cardiac myocytes. These studies will lead to a better understanding of cardiac remodeling in chagasic cardiomyopathy, an emerging opportunistic infection in AIDS. In addition, it will provide potential targets of adjunctive therapy.