Molecular Pathogenesis of the Cardiomyogenic Defects in LEOPARD Syndrome

描述(由申请人提供)： 摘要：最近，含有SH2结构域的蛋白酪氨酸磷酸酶Shp2的突变被认为与心脏病有关。Shp2基因在大约50%的Noonan综合征(NS)病例和所有豹子综合征(LS)病例中被确定为突变。NS和LS有几个共同的临床特征，包括先天性心脏缺陷，因此，被视为重叠综合征。然而，LS不是NS的疾病变种；Shp2中的LS相关突变是催化不活跃的，表现为显性阴性，而NS中的Shp2突变是催化过度活跃的。这提出了一个模型，在该模型中，LS突变是功能丧失，NS突变是功能增益。此外，大多数LS患者发生肥厚性心肌病(HCM)，这是LS独有的；少数携带Shp2突变的NS患者发生HCM。因此，中心假设是，这两种综合征之间的生化差异会导致不同的心脏缺陷。该方案将确定Shp2 LS突变体干扰ERK/MAPK通路中RAS上游和/或下游的正信号事件的机制(S)，将确定心脏中LS异常调节的信号通路，将确定心脏发生过程中Shp2所需的发育间隔，并将产生并功能分析LS的小鼠模型。候选人：Maria Kontaridis将接受心脏病学领域的高级培训，并将在该奖项的指导阶段进一步发展分子和发育生物学、生物化学和老鼠遗传学方面的技能。她的赞助人本杰明·尼尔是Shp2和老鼠遗传学方面的专家。她的顾问小组(乔纳森·塞德曼博士、杰弗里·萨菲兹博士、刘易斯·坎特利博士和詹姆斯·张博士)都是心脏发育/病理生理学和/或信号转导方面的专家，他们将对她的培训和职业发展做出重大贡献。从长远来看，她计划成为一家学术机构的独立研究科学家，并领导自己的实验室研究心脏发育，重点是导致先天性心脏病的信号机制(及其突变)。 相关性：这项工作将进一步定义基因突变导致心脏疾病的机制 疾病。这些发现将通过更好地了解介导这些过程的基本信号机制来促进我们对心脏功能和发病机制的了解。 (摘要结束)

DESCRIPTION (provided by applicant): SUMMARY: Recently, mutations in the SH2 domain-containing protein tyrosine phosphatase Shp2, have been implicated in cardiac disease. Shp2 was identified as the gene mutated in approximately 50% of cases of Noonan Syndrome (NS) and all cases of LEOPARD Syndrome (LS). NS and LS share several clinical features, including congenital heart defects, and, as such, were viewed as overlap syndromes. However, LS is NOT a disease variant of NS; LS-associated mutations in Shp2 are catalytically inactive and behave as dominant negatives, whereas Shp2 mutations in NS are catalytically hyperactive. This proposes a model in which LS mutations are loss-of-function and NS mutations are gain-of-function. Moreover, most LS patients develop a hypertrophic cardiomyopathy (HCM), which is unique to LS; few NS patients with Shp2 mutations develop HCM. The central hypothesis, therefore, is that biochemical differences between these two syndromic disorders give rise to distinct cardiac defects. This proposal will define the mechanism(s) by which Shp2 LS mutants interfere with positive signaling events upstream and/or downstream of Ras in the Erk/MAPK pathway, will determine the signaling pathways that are aberrantly regulated by LS in the heart, will identify the developmental interval in which Shp2 is required during cardiogenesis, and will generate and functionally analyze a murine model of LS. CANDIDATE: Maria Kontaridis will receive advanced training in the field of cardiology and will further develop skills in molecular and developmental biology, biochemistry, and mouse genetics during the mentored phase of this award. Benjamin Neel, her sponsor, is an expert in Shp2 and mouse genetics. Her advisory panel (Drs. Jonathan Seidman, Jeffrey Saffitz, Lewis Cantley and James Chang), all experts in cardiac development/pathophysiology and/or signal transduction, will contribute substantially to her training and career development. Long-term, she plans to become an independent research scientist at an academic institution and to direct her own lab in cardiac development, with an emphasis on the signaling mechanisms (and mutations therein) that lead to congenital heart disease. RELEVANCE: This work will further define the mechanisms by which genetic mutations lead to cardiac disease. These findings will advance our knowledge of cardiac function and pathogenesis through better understanding of the fundamental signaling mechanisms that mediate these processes. (End of Abstract)