Aquaporin 1 and pulmonary hypertension

项目总结 肺动脉高压(PAH)是一种无法治愈的严重衰弱疾病。形态测量学 研究表明，肺动脉高压的发展与强健的结构有关。 肺小动脉重塑，特征是内皮细胞和平滑肌增厚 细胞层和闭塞病变的形成。除了增加血管的增殖和迁移 细胞，适当的凋亡失败(即，抗凋亡)通过缺乏细胞而导致重塑 营业额。我们的实验室确定了一种新的候选细胞作为肺动脉平滑肌细胞的调节剂。 PASMC功能：水通道蛋白(AQPs)。水通道蛋白是一类形成跨膜通道的蛋白质。 这有助于水进出细胞的运输。我们有证据表明水通道蛋白1(AQP1)，第一个 已鉴定的家族成员，表达于PASMC和肺微血管内皮细胞(PMVECs)， 在PAH大鼠模型中上调，并调节对细胞凋亡的敏感性。我们的初步数据还表明 水通道蛋白1蛋白的增加与β-连环蛋白表达的增加有关，这是一种调节 迁移、增殖和存活反应。水通道蛋白1调节β-连环蛋白水平的机制是 目前尚不清楚；我们已经生成了令人兴奋的数据，表明AQP1的特定区域具有关键作用 C-末端尾巴。该区域包含一个先前未知的与Gsk3β的推测结合位点，Gsk3是一种内源性 β-连环蛋白丰度的调节。基于这些数据，我们假设在PAH PASMC和PMVEC中， 水通道蛋白1水平的增加通过隔离GSK3β并减少其 活性/核定位；结果，β-连环蛋白积聚，促进迁移和扩散 和防止细胞凋亡。本研究的目的是：1)确定水通道蛋白1是否通过调节β-连环蛋白 结合Gsk3β；2)确定水通道蛋白1促进细胞生长和存活的机制；3) 评估AQP1的细胞特异性干扰是否可以预防或逆转PAH。

PROJECT SUMMARY Pulmonary arterial hypertension (PAH) is a severely debilitating disease with no cure. Morphometric studies revealed that the development of pulmonary hypertension is associated with robust structural remodeling of the small pulmonary arteries, characterized by thickening of the endothelial and smooth muscle cell layers and formation of occlusive lesions. In addition to increased proliferation and migration of vascular cells, failure of appropriate apoptosis (i.e., apoptotic resistance) contributes to remodeling via lack of cell turnover. Our laboratory identified a new candidate as a regulator of pulmonary arterial smooth muscle cell (PASMC) function: aquaporins (AQPs). AQPs are a family of proteins that form transmembrane channels which facilitate the transport of water into and out of cells. We have evidence that aquaporin 1 (AQP1), the first family member identified, is expressed in PASMCs and pulmonary microvascular endothelial cells (PMVECs), upregulated in a rat model of PAH and modulates susceptibility to apoptosis. Our preliminary data also indicate that increased AQP1 protein is associated with elevated β-catenin expression, a protein that regulates migratory, proliferative and survival responses. The mechanism by which AQP1 regulates β-catenin levels is currently unknown; we have generated exciting data indicating a critical role for a specific region of the AQP1 C-terminal tail. This region contains a previously unrecognized putative binding site for GSK3β, an endogenous regulator of β-catenin abundance. Based on these data, we hypothesize that in PAH PASMCs and PMVECs, increased AQP1 levels contribute to cell growth and survival by sequestering GSK3β and reducing its activity/nuclear localization; as a consequence, β-catenin accumulates, promoting migration and proliferation and preventing apoptosis. The Aims of this study are to: 1) determine whether AQP1 regulates β-catenin via binding to GSK3β; 2) identify the mechanism by which AQP1 facilitates cell growth and survival; and 3) evaluate whether cell-specific disruption of AQP1 prevents or reverses PAH.