SPECIALIZED CENTER OF RESEARCH IN HEART FAILURE

当前SCOR和拟议更新的总体目标是阐明心脏对损伤的长期适应性反应的分子基础，包括遗传性和获得性损伤，表现为肥大或扩张。该提案包括5项合作研究，由综合核心设施支持，以解决心力衰竭病因、发病机制和治疗的基本问题。新的基因将被确定为负责遗传性心脏疾病，家族性扩张型心肌病（FDCM）表现在左心室和心律失常性右心室发育不良的右心室，扩张型心肌病，获得性心力衰竭的最常见形式的范例。迄今为止，已经鉴定了两种基因（细胞骨架），导致DCM，肌动蛋白和结蛋白。因此，细胞骨架蛋白可能提供了一个统一的因果关系DCM类似的肌节蛋白的HCM。因此，从转基因小鼠中突变结蛋白的表达中获得的见解应该对由于其他缺陷的细胞骨架蛋白（无论是家族性的还是获得性的）而导致的DCM具有致病意义。虽然细胞骨架组分的组装和组织是心脏生长反应的组成部分，但它们的作用迄今为止一直被忽视，直到鉴定出整合素信号传导途径（RhoA、局灶性粘附激酶和整合素连接激酶）。在Schwartz博士的项目中，这些分子的显性负突变体将用于心肌细胞和基因开关转基因，以确定这些分子中的一个或全部是否是细胞骨架组装和肥大所必需的。FHCM由于7个基因中的100多个突变，发展出增加的纤维化和肥大的继发表型，为预防提供了机会。将在携带人cTNT突变的转基因动物中评估肾素-血管紧张素系统（RAS）抑制剂，为将来的基因治疗做准备，将使用基因转换来确定表型是否可逆。将通过消减杂交寻找导致次要表型的生长因子。在当前SCOR中显示的在生长反应（肥大）和心力衰竭（细胞凋亡）中发挥关键作用的新途径（TNF α）将被用于在遗传模型和心力衰竭患者中鉴定与RAS的分子相互作用，并开发新的特异性治疗。实现目标的战略将利用“最先进”的技术：用于基因分型和DNA测序的自动基因分析仪，用于识别基因的BAC、YAC和DNA微芯片阵列，用于调节转基因表达的RU-486基因开关，PCR产生的显性阴性突变体，“无肠”四环素依赖性腺病毒载体，选择性消除基因（基因敲除小鼠）和Ta 178放射性核素血管造影术以评估小鼠心脏功能。这些研究进一步阐明了心肌肥厚和心力衰竭的分子基础，为更有效的治疗提供了合理的依据。

The overall objective of the current SCOR and the Proposed Renewal is to elucidate the molecular basis for the long-term adaptive response of the heart to injury, both inherited and acquired, where manifested by hypertrophy or dilitation. This proposal encompasses 5 collaborative investigations, supported by integrated core facilities to address issues fundamental to the etiology, pathogenesis and treatment of cardiac failure. Novel genes will be identified responsible for inherited cardiac disorders, familial dilated cardiomyopathy (FDCM) manifested in the left ventricle and arryhthmogenic right ventricular dysplasia in the right ventricle, as paradigms of dilated cardiomyopathy, the most common form of acquired heart failure. To date, two genes (cytoskeletal) have been identified that cause DCM, actin and desmin. Thus, cytoskeletal proteins may provide a unifying causality for DCM analogous to that of sarcomeric proteins for HCM. Accordingly, insight gained from expression of the mutant desmin in the transgenic mouse should have pathogenetic implications for DCM due to other defective cytoskeletal proteins, whether familial or acquired. While assembly and organization of the cytoskeletal components are an integral part of the cardiac growth response, their role as heretofore been ignored until the identification of the integrin signaling pathway (RhoA, Focal Adhesion Kinase, and Integrin Linked Kinase). In Dr. Schwartz' project, dominant negative mutants of these molecules will be used in cardiac myocytes and Gene-Switch transgenics to determine whether one or all of these are necessary for cytoskeletal assembly and hypertrophy. FHCM, due to over 100 mutations in seven genes, develops the secondary phenotype of increased fibrosis and hypertrophy, providing the opportunity for prevention. Renin-angiotensin system (RAS) inhibitors will be assessed in transgenics harboring the human cTNT mutation and, in preparation for future gene therapy, Gene-Switch will be used to determine if the phenotype is reversible. Growth factor(s) responsible for the secondary phenotype will be sought through subtraction hybridization. A novel pathway (TNFalpha) shown in the current SCOR to play a pivotal role in the growth response (hypertrophy) and heart failure (apoptosis), will be pursued to identify molecular interaction with RAS, both in genetic models and in patients with heart failure and to develop novel specific therapies. Strategies to achieve the aims, will utilize "state of the art" techniques: automated genetic analyzers for genotyping and DNA sequencing, BACs, YACs, and DNA microchip arrays to identify genes, the RU-486 Gene Switch to regulate expression of transgenes, PCR-generated dominant negative mutants, "gutless" tetracycline dependent adenoviral vectors, selective elimination of genes (knock-out mice), and Ta178 radionuclide angiography to assess mouse cardiac function. These studies elucidate further the molecular foundations of cardiac hypertrophy and failure and should provide a rational basis for more effective therapy.