GENETICS OF EXTRACELLULAR MATRIX IN HEALTH AND DISEASE

描述（由申请人提供）：这些研究的长期目标是阐明弹性细胞外基质在人类发育和生理学中的功能，揭示弹性纤维（EF）功能障碍引起的疾病的分子机制，并为这些疾病开发新的治疗策略。最近的一些证据强调了EF组装的复杂性。细胞生物学和生物化学研究说明了EF生物发生的动态，分层和细胞介导的性质。然而，这一过程的关键分子决定因素仍然难以捉摸。对血管异常、肺气肿和皮肤拉克萨患者的分子遗传学研究表明，EF形成的不同步骤需要多个基因。这些研究鉴定了弹性蛋白、纤蛋白-4、纤蛋白-5和α 2亚基v型H+ ATP酶的基因突变，突出了弹性蛋白生成所需的分子网络的存在。我们研究的新的初步数据表明，不同皮肤拉克萨突变的下游效应包括转化生长因子β（TGF β）信号转导的失调。基于这些结果，我们假设皮肤拉克萨是由EF生物合成在多个水平上的破坏引起的，导致弹性纤维的结构破坏和细胞外基质中TGF β的储存和释放改变。为了解决这些假设，我们提出（1）通过鉴定皮肤拉克萨、肺气肿和血管异常患者的致病突变来研究人类EF形成的遗传程序。除了最近发现的基因突变谱，我们将使用候选基因分析，以确定这些疾病的新基因。在目标2中，我们将使用EF组装的体外模型来鉴定受拉克萨突变影响的细胞外基质分子之间的分子相互作用序列。我们还将测试EF功能障碍是否会通过使TGF β的大的潜在复合物不稳定而导致不适当的TGF β释放。在目标3中，我们打算以斑马鱼为模型，剖析fibulin-4和相关分子在早期血管形成和随后的血管成熟中的作用。我们将使用遗传学和小分子药物来确定EF功能障碍和改变的TGF β信号传导对发育性病变的贡献。

DESCRIPTION (provided by applicant): The long-range objectives of these studies are to elucidate the functions of the elastic extracellular matrix in human development and physiology, to uncover the molecular mechanisms of disease caused by elastic fiber (EF) dysfunction and to develop novel treatment strategies for these diseases. Several lines of recent evidence highlight the complexity of EF assembly. Cell biological and biochemical studies illustrate the dynamic, hierarchical and cell mediated nature of EF biogenesis. However, key molecular determinants of this process have remained elusive. Molecular genetic studies of patients with vascular anomalies, emphysema and cutis laxa show that multiple genes are required for distinct steps of the EF formation. These studies identified mutations in the genes for elastin, fibulin-4, fibulin-5 and the a2 subunit v- type H+ATPase, highlighting the existence of a network of molecules required for elastogenesis. New preliminary data from our studies now suggest that a downstream effect of different cutis laxa mutations includes dysregulation of transforming growth factor beta (TGFb) signaling. Based on these results we hypothesize that cutis laxa is caused by the disruption of EF biogenesis at multiple levels leading to both structural disruption of elastic fibers and by altered storage and release of TGFb in the extracellular matrix. To address these hypotheses we propose (1) to investigate the genetic program of human EF formation by identifying disease-causing mutations in patients with cutis laxa, emphysema and vascular anomalies. In addition to mutational profiling of recently discovered genes, we will use candidate gene analysis to identify novel genes for these disorders. In aim 2, we will use in vitro models of EF assembly to identify the sequence of molecular interactions between extracellular matrix molecules impacted by cutis laxa mutations. We will also test if EF dysfunction leads to inappropriate TGFb release by destabilizing the large latent complex of TGFb. In aim 3, we intend to dissect the role of fibulin-4 and related molecules in early vascular patterning and subsequent blood vessel maturation using zebrafish as a model. We will use genetics and small molecule drugs to identify the contribution of EF dysfunction and altered TGFb signaling to developmental lesions.