Genetics of extracellular matrix in health and disease

 描述(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中的功能，揭示由弹性纤维(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。最近的几行证据强调了EF组装的复杂性。细胞生物学和生化研究阐明了EF生物发生的动态性、层次性和细胞介导性。然而，这一过程的关键分子决定因素仍然难以捉摸。对血管畸形、肺气肿和皮肤松弛(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。这些研究发现了弹性蛋白、纤维蛋白-4、纤维蛋白-5、v型H+-ATPase的a2亚单位以及潜在的转化生长因子β结合蛋白4(LTBP4)基因的突变，突显了弹性形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，并表明不同的皮肤松弛突变的下游效应包括通过新的机制调节转化生长因子β信号。根据这些结果，我们推测皮肤松弛是由于EF生物发生在多个水平上的中断，导致弹性纤维的结构破坏，以及通过改变细胞外基质中生长因子的储存和释放，以及通过影响生长因子受体的稳定性和活性而引起的。为了解决这些假设，我们建议(1)通过对CL、肺气肿和血管畸形患者进行深入的表型和鉴定致病突变，来研究人类EF形成的遗传程序。除了最近发现的基因突变图谱外，我们还将使用整个外显子组测序、RNA测序和阵列比较基因组杂交来识别这些疾病的新基因。在目标2中，我们将使用EF组装的体外模型来确定受皮肤松弛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，我们打算研究皮肤松弛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在发育损害中的作用。

 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.