PKD1-Fibrillin Interactions and TFG-b Signaling Pathways

PKD1-原纤维蛋白相互作用和 TFG-b 信号通路

• 批准号: 7136921
• 负责人: Terry J Watnick
• 金额: $ 30.66万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7136921
• 关键词: Marfan syndrome; alleles; aorta; aorta disorder; autosomal dominant trait; biological signal transduction; blood vessel disorder; calcium channel; family genetics; fibrillin; gene interaction; genetically modified animals; histopathology; laboratory mouse; medical complication; molecular pathology; pathologic process; polycystic kidney; protein protein interaction; protein signal sequence; transcription factor; transforming growth factors

DESCRIPTION (provided by applicant): Autosomal dominant polycystic kidney disease (ADPKD) is the most common form of inherited renal failure in the US. Although the disease is named for its most notable feature, namely kidney cysts, vascular complications are in fact a significant cause of morbidity and mortality. Based on the association of aneurysms and ADPKD it has been speculated that polycystins (PKD proteins) play an important role in maintaining vascular integrity of blood vessels but the precise cellular function of polycystins in the vasculature has not been defined. In support of this hypothesis, animals with mutations in either PKD gene die in utero and often exhibit hemorrhage with leaky blood vessels and edema. Despite the significance of this problem, the precise cellular function of polycystins in the vasculature has not yet been defined. We believe that exciting new clues may come from the relationship between PKD and connective tissue diseases such as Marfan syndrome (MFS) that also have a prominent vascular phenotype. Until recently it was assumed that the pathogenic mechanism underlying the MFS phenotype had to do with the structural failure of the ECM. However, recent work suggests that over activity of TGF-beta signaling may play a role in disease pathogenesis. The observation that families with ADPKD and MFS have overlapping clinical features prompted us to test for a functional interaction between 2 gene products. Our preliminary studies demonstrate that mice which are heterozygous for mutations in Pkd1 and the MFS gene, Fbn1, have a remarkable increase in the aortic wall pathology as well as evidence of increased TGF-beta signaling. This application seeks to define the mechanism that is responsible for this genetic interaction. In the first aim we will test the hypothesis that loss of a Pkd1 or Pkd2 allele results in worsening of the histopathologic features of MFS. The goal of Aim 2 is to understand how Fbn1 and Pkd1 cooperatively modulate TGF-beta signaling. We will use a variety of histochemical, cell culture and in vivo methods to interrogate the TGF-beta signaling. Aim 3 will extend these studies by asking whether Pkd1 affects TGF-beta signaling via STAT-1 dependent induction of the inhibitory SMAD7. Aim 4 will test the hypothesis that disruption of the Pkd1 alone results in a vascular phenotype and that is associated with the dysregulation of TGF-beta superfamily signaling. We anticipate that an improved understanding of vascular signaling pathways in ADPKD will result in therapeutic approaches that could be applied to the treatment or prevention of some of the most devastating consequences of this disease. We propose the following specific aims: Specific Aim 1: Elucidate the pathogenesis of the aortic phenotype in mice carrying compound heterozygous Pkd/Fbn mutations. Specific Aim 2: Interrogate the TGF-B signaling pathway in Pkd/Fbn Compound Heterozygotes. Specific Aim 3: Test the hypothesis that PKD1 affects TGF-B signaling via STAT-1 dependent induction of the inhibitory SMAD7. Specific Aim 4: Test the hypothesis that disruption of Pkd1 is sufficient to modulate TGF-B related signaling pathways.

描述（由申请人提供）：常染色体显性多囊肾病（ADPKD）是美国最常见的遗传性肾衰竭形式。尽管该疾病因其最显着的特征（即肾囊肿）而得名，但血管并发症实际上是发病和死亡的重要原因。基于动脉瘤和 ADPKD 的关联，推测多囊蛋白（PKD 蛋白）在维持血管完整性方面发挥着重要作用，但多囊蛋白在脉管系统中的精确细胞功能尚未明确。为了支持这一假设，携带 PKD 基因突变的动物会在子宫内死亡，并且经常表现出出血、血管渗漏和水肿。尽管这个问题很重要，但多囊蛋白在脉管系统中的精确细胞功能尚未确定。我们相信，令人兴奋的新线索可能来自 PKD 与结缔组织疾病（如马凡综合征 (MFS)）之间的关系，这些疾病也具有显着的血管表型。直到最近，人们还认为 MFS 表型的致病机制与 ECM 的结构故障有关。然而，最近的研究表明，TGF-β 信号传导的过度活跃可能在疾病发病机制中发挥作用。 ADPKD 和 MFS 家族具有重叠临床特征的观察结果促使我们测试两种基因产物之间的功能相互作用。我们的初步研究表明，Pkd1 和 MFS 基因 Fbn1 突变的杂合小鼠的主动脉壁病理显着增加，并且有证据表明 TGF-β 信号传导增加。本申请旨在定义导致这种遗传相互作用的机制。第一个目标是检验 Pkd1 或 Pkd2 等位基因缺失会导致 MFS 组织病理学特征恶化的假设。目标 2 的目标是了解 Fbn1 和 Pkd1 如何协同调节 TGF-β 信号传导。我们将使用各种组织化学、细胞培养和体内方法来研究 TGF-β 信号传导。目标 3 将通过询问 Pkd1 是否通过 STAT-1 依赖性诱导抑制性 SMAD7 影响 TGF-β 信号传导来扩展这些研究。目标 4 将检验以下假设：单独破坏 Pkd1 会导致血管表型，并且与 TGF-β 超家族信号传导失调相关。我们预计，对 ADPKD 血管信号通路的进一步了解将带来可用于治疗或预防该疾病的一些最具破坏性后果的治疗方法。我们提出以下具体目标： 具体目标 1：阐明携带复合杂合 Pkd/Fbn 突变的小鼠主动脉表型的发病机制。具体目标 2：探究 Pkd/Fbn 复合杂合子中的 TGF-B 信号通路。具体目标 3：检验 PKD1 通过 STAT-1 依赖性诱导抑制性 SMAD7 影响 TGF-B 信号转导的假设。具体目标 4：检验 Pkd1 的破坏足以调节 TGF-B 相关信号通路的假设。