MK2 and pulmonary hypertension

项目总结 肺动脉高压(PAH)是一种致命的、使人衰弱的疾病，无法治愈。的发展。 PAH与包括内膜在内的小肺动脉的强健结构重构有关 血管闭塞病变的增厚和形成。除了异常增加的血管增殖 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。我们实验室最近发现，蛋白丝氨酸激酶MAPKAP2的表达 (MK2)在肺微血管内皮细胞(PMVECs)中显著下调。 SU5416+低氧(SuHx)大鼠PAH模型。关于MK2表达的控制知之甚少；然而， 我们的初步数据表明，MK2受低氧诱导因子(HIF)的调控，HIF是一个转录家族 提示影响多环芳烃发生发展的因素。MK2的丢失与胞浆有关 封闭caspase-3，防止细胞凋亡。此外，我们将MK2水平的降低与上调联系在一起 在水通道中，水通道蛋白1(AQP1)，我们之前已经证明它促进促增殖作用 在肺血管细胞中。然而，MK2可能影响AQP1表达的机制是 未知。基于这些数据，我们假设在PAH PMVEC中，依赖于HIF的MK2下调 结果导致caspase-3的胞浆隔离和AQP1的上调，导致细胞凋亡抵抗和 分别为过度增殖。因此，本研究的目的是：1)确定MK2是否在 PAH介导caspase-3的胞浆隔离；2)决定MK2控制AQP1的机制 3)评估MK2的表达增加是否逆转了细胞表型的变化和 肺动脉高压中的血管重塑。我们将使用一种综合的、多学科的方法，结合体外和体内 PAH活体模型探讨该通路调控因素对PMVEC细胞功能和功能的影响 多环芳烃的发展和逆转。拟议研究的成功完成将通过以下方式对该领域产生影响： 1)描述由MK2介导的信号通路，这些信号通路参与肿瘤的发生和发展 PAH；2)提供有关MK2表达调控的新信息；3)确定特定的相互作用 在负责控制caspase-3亚细胞定位的caspase-3、MK2和AQP1之间，以及 AQP1诱导PMVEC生长；4)指导后续研究，旨在开发新的 治疗学。

PROJECT SUMMARY Pulmonary arterial hypertension (PAH) is a deadly, debilitating disease with no cure. The development of PAH is associated with robust structural remodeling of the small pulmonary arteries, including intimal thickening and formation of vaso-occlusive lesions. In addition to abnormally increased proliferation of vascular cells, failure of appropriate apoptosis (i.e., apoptotic resistance) contributes to remodeling via lack of cell turnover. Our laboratory recently discovered that the expression of the protein-serine kinase, MAPKAP2 (MK2), is markedly downregulated in pulmonary microvascular endothelial cells (PMVECs) from the SU5416+hypoxia (SuHx) rat model of PAH. Little is known regarding the control of MK2 expression; however, our preliminary data indicate that MK2 is regulated by hypoxia-inducible factors (HIFs), a family of transcription factors suggested to be involved in the development of PAH. Loss of MK2 is associated with cytosolic sequestration of caspase-3, preventing apoptosis. Moreover, we linked reduced MK2 levels with upregulation of the water channel, aquaporin 1 (AQP1), which we previously have shown promotes pro-proliferative effects in pulmonary vascular cells. However, the mechanism by which MK2 might influence AQP1 expression is unknown. Based on these data, we hypothesize that in PAH PMVECs, HIF-dependent downregulation of MK2 results in cytosolic sequestering of caspase-3 and upregulation of AQP1, leading to apoptotic resistance and hyperproliferation, respectively. Thus, the Aims of this study are to: 1) determine whether loss of MK2 during PAH mediates cytosolic sequestering of caspase-3; 2) determine the mechanism by which MK2 controls AQP1 expression; and 3) evaluate whether increasing the expression of MK2 reverses changes in cell phenotype and vascular remodeling in PAH. We will use a comprehensive, multidisciplinary approach combining in vitro and in vivo models of PAH to explore the effect of modulating factors in this pathway on PMVEC cell function and development and reversal of PAH. The successful completion of the proposed studies will impact the field by: 1) describing signaling pathways mediated by MK2 that are involved in the development and progression of PAH; 2) providing new information regarding regulation of MK2 expression; 3) identifying specific interactions between caspase-3, MK2 and AQP1 that are responsible for controlling caspase-3 subcellular localization and AQP1-induced PMVEC growth; and 4) directing subsequent studies aimed at development of new therapeutics.