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（CL）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、v型H+-ATP酶的α 2亚基和潜在转化生长因子β结合蛋白4（LTBP 4）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现在证明了新的CL基因的存在，并表明不同皮肤拉克萨突变的下游效应包括通过新机制调节转化生长因子β（TGF β）信号转导。基于这些结果，我们推测，拉克萨是由EF生物合成在多个水平上的破坏导致弹性纤维的结构破坏和细胞外基质中生长因子的储存和释放的改变以及影响生长因子受体的稳定性和活性引起的。为了解决这些假设，我们建议（1）通过深入的表型分析和识别CL、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，我们将使用全外显子组测序，RNA测序和阵列比较基因组杂交，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。我们还将研究EF功能障碍导致生长因子活性失调的机制。在目标3中，我们打算研究皮肤拉克萨基因在早期心血管和结缔组织发育中的作用。我们将使用遗传学和小分子药物来确定EF功能障碍和改变的生长因子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 (CL) 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, the a2 subunit of the v- type H+-ATPase, and the latent transforming growth factor beta-binding protein 4 (LTBP4), highlighting the existence of a network of molecules required for elastogenesis. New preliminary data from our studies now demonstrate the existence of new CL genes and show that a downstream effect of different cutis laxa mutations includes dysregulation of transforming growth factor beta (TGFß) signaling through novel mechanisms. 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 altere storage and release of growth factors in the extracellular matrix and by affecting the stability an activity of growth factor receptors. To address these hypotheses we propose (1) to investigate the genetic program of human EF formation by in-depth phenotyping and identifying disease-causing mutations in patients with CL, emphysema and vascular anomalies. In addition to mutational profiling of recently discovered genes, we will use whole exome sequencing, RNA sequencing and array comparative genomic hybridization 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 study the mechanisms by which EF dysfunction leads to dysregulation of growth factor activity. In aim 3, we intend to investigate dissect the role of cutis laxa genes in early cardiovascular and connective tissue development. We will use genetics and small molecule drugs to identify the contribution of EF dysfunction and altered growth factor signaling to developmental lesions.