MOLECULAR ANALYSIS OF DYSTROPHIC CARDIAC CALCIFICATION

人类心血管系统中与血管病相关的营养不良性钙化 系统是非常常见的，也许比缺血性更普遍 心脏病在最老的年龄组， 对心功能不全有很大影响尽管发病率很高， 临床意义，很少有实验模型系统存在， 几乎没有可用的机械数据。我们建议利用已知的 小鼠的遗传易感性，以进一步描述 了解心血管变性和钙化， 衰老 这个应用程序的长期目标是识别特定的 自发性营养不良性心脏钙化（DCC）相关基因 DBA/2（D2）系小鼠。DCC是一种年龄相关的菌株特异性 主要发生在D2小鼠的心肌损伤和相关 菌株DCC的易感性由至少两个常染色体 隐性基因;一个人的居住地似乎已经缩小 一个染色体区域。Dyscalc，我们最近从 提名候选基因。我们在这个试点项目中的目标 应用是：（1）进行基因组排除作图研究 使用序列标记的位点标记来识别所有 DCC基因座;和（2）进行新的初步评估 基于候选基因Myocyte的DCC机制假说 增强因子2A（MEF 2A），肌肉中的关键转录因子。 MEF 2A映射到Dyscalc区域并控制Dyscalc的表达。 中间丝蛋白结蛋白基因敲除小鼠 表现出与DCC相似的表型。我们假设D2 MEF 2A 基因改变某些关键基因的表达，如结蛋白 可能通过细胞凋亡导致DCC。我们建议执行 基于组织学的凋亡测定和免疫组织化学分析 结蛋白和波形蛋白在来自DCC敏感菌株D2的心脏上的表达， C57 BL/6（B6）小鼠来验证这一假设。另外我们 计划在D2中进行MEF 2A基因的初步结构分析 B6小鼠实现这些目标将具有重大意义 在确定DCC相关的特定基因方面取得了进展， 评估MEF 2A的潜在作用，提供有价值的 为后续研究提供初步数据。基因赋予 小鼠对DCC的易感性应该提供一种新的分子机制， 人类发生年龄相关钙化的方法 心血管系统

Age-related dystrophic calcification in the human cardiovascular system is extremely common, perhaps more prevalent than ischemic heart disease in the oldest age groups, and can contribute significantly to cardiac dysfunction. Despite the high prevalence and clinical significance, few experimental model systems exist and little mechanistic data are available. We propose to exploit a known genetic susceptibility in mice to further delineate the molecular understanding of cardiovascular degeneration and calcification in aging. The long-range goal of this application is to identify the specific genes underlying spontaneous dystrophic cardiac calcification (DCC) in strain DBA/2 (D2) mice. DCC is an age-related strain-specific lesion mainly of cardiac muscle occurring in D2 mice and related strains. Susceptibility to DCC is conferred by at least two autosomal recessive genes; the residence of one appears to have been narrowed to one chromosomal region. Dyscalc, from which we have recently nominated a candidate gene. Our objectives in this pilot project application are to: (1) perform a genome exclusion mapping study using sequence tagged site markers to identify the locations of all DCC loci; and (2) conduct the initial evaluation of a novel mechanistic hypothesis for DCC based upon a candidate gene, Myocyte Enhancer Factor 2A (MEF2A), a key transcription factor in muscle. MEF2A maps to the Dyscalc region and controls the expression of the intermediate filament protein desmin; desmin null knockout mice manifest a close phenocopy of DCC. We hypothesize that the D2 MEF2A gene alters the expression of certain critical genes such as desmin that result in DCC, perhaps through apoptosis. We propose to perform a histological based apoptosis assay and immunohistochemical analysis of desmin and vimentin on hearts from DCC sensitive strain D2 and resistant C57BL/6 (B6) mice to test this hypothesis. In addition, we plan to conduct initial structural analysis of the MEF2A gene in D2 and B6 mice. Completion of these aims will constitute significant progress toward identifying the specific genes underlying DCC and evaluating the potential role of MEF2A, providing valuable preliminary data for subsequent studies. The genes conferring susceptibility to DCC in mice should provide a novel molecular approach to age-related calcification occurring in the human cardiovascular system.