HIPPO Signaling in Pulmonary Arterial Hypertension

肺动脉高压(PAH)是一种进展性的致命性疾病，以肺血管重构为主要表现。 特里斯(PA)，导致PA压力增加，右心衰竭和死亡。PA重塑的关键组件 PA血管平滑肌细胞(PAVSMC)的增殖和存活增加与EXCES有关。 分泌细胞外基质(ECM)。我们最近发现了LATS1的功能障碍，LATS1是生长发育的成员- 抑制河马盒作为支持PAH增殖/抗凋亡PAVSMC表型的关键事件。 类型，剖析了通过上调YAP/Taz-ILK1而使LATS1失活的机制，并证明了本研究的结论。 抑制ILK1可恢复LATS1功能，逆转肺血管重构，降低PH。这个 河马的其他成分，蛋白激酶MST1/2，在PAH中的作用仍有待确定。我们发现了 结论：PAH中的MST1/2具有独特的促增殖/促生存作用，支持细胞增殖和增殖抑制。 人PAH-PAVSMC存活、肺血管重塑和肺高压我们报告说，这一功能 MST1/2依赖于Akt和独特的PAH与细胞周期蛋白Bub3的特异性相互作用。此外，我们还证明了 MST1/2和Bub3通过支持细胞分裂周期蛋白CDC20的过度表达而发挥作用，从而导致缺陷 促凋亡的Bim、Akt、mTORC1和YAP/Taz的激活，增加了增殖、存活和过度促进 ECM的诱导。反过来，由人PAH PAVSMC产生的ECM上调Bub3，Akt-mTORC1，YAP/Taz， 和PAVSMC增殖，并诱导PA内皮细胞和外膜成纤维细胞生长 (PAAF)。最后，我们的数据表明，对MST1/2的药物抑制可以逆转PAH特异的信号转导途径。 并选择性地抑制人PAH-PAVSMC的增殖和/或促进其凋亡 未患病的细胞。在下一个资助期，我们建议阐明角色、监管机制和 MST1/2在PAH中的作用，并探讨靶向MST1/2信号转导纠正PAH机制异常的益处。 男性和逆转PA重塑和PH。具体地说，我们将：(1)批判性地评估MST1和MST2的作用，其 在调节Akt、mTORC1和YAP/Taz网络中相互作用的伙伴Bub3和下游效应子CDC20， 人和正常肺血管内皮细胞增殖和存活、肺血管重塑和肺高压 组织和PAVSMC以及具有VSM特异性Mst1/2基因敲除的小鼠；(2)确定病理功能 PAH PAVSMC中MST1/2的支持由Akt直接支持或通过Akt-Bub3-Yap/Taz前馈环路支持，并评估 MST1/2在细胞外基质重塑和细胞外基质依赖性增殖中的作用； 通过药物抑制MST1/2激酶、Akt或(Alterna-2)来靶向MST1/2信号转导的潜在益处 CDC20选择性抑制增殖、诱导细胞凋亡和减少病理性细胞外基质产生 通过人PAH PAVSMC抑制PAEC和PAAF的过度增殖并逆转实验 肺血管重构与肺高压。这项拟议的研究将确定一种新的肺源性心脏病的关键机制 血管重塑，并解剖新的重塑焦点分子靶点(S)进行治疗干预。 。

Pulmonary arterial hypertension (PAH), a progressive fatal disease, manifests by remodeling of pulmonary ar- teries (PA), leading to increased PA pressure, right heart failure and death. Key components of PA remodeling are increased proliferation and survival of PA vascular smooth muscle cells (PAVSMC) associated with exces- sive extracellular matrix (ECM) production. We recently identified dysfunction of LATS1, a member of growth- suppressor HIPPO cassette, as a key event supporting proliferative/apoptosis-resistant PAH PAVSMC pheno- type, dissected the mechanism of LATS1 inactivation via up-regulation of Yap/Taz-ILK1, and demonstrated ben- efits of ILK1 inhibition to restore LATS1 function, reverse pulmonary vascular remodeling and reduce PH. The role of other HIPPO components, protein kinases MST1/2, in PAH remains to be established. We have found that MST1/2 in PAH play a unique pro-proliferative/pro-survival role and support increased proliferation and sur- vival of human PAH PAVSMC, pulmonary vascular remodeling and PH in mice. We report that this function of MST1/2 depend on Akt and unique PAH-specific interaction with cell cycle protein BUB3. Further, we show that MST1/2 and BUB3 act via supporting overexpression of cell-division cycle protein CDC20, consequent deficiency of pro-apoptotic Bim, activation of Akt, mTORC1, and Yap/Taz, increased proliferation, survival, and over-pro- duction of ECM. In turn, ECM, produced by human PAH PAVSMC, up-regulates BUB3, Akt-mTORC1, Yap/Taz, and PAVSMC proliferation, and induces growth of PA endothelial cells (PAEC) and adventitial fibroblasts (PAAF). Lastly, our data show that pharmacological inhibition of MST1/2 reverses PAH-specific signaling abnor- malities and selectively inhibits proliferation and/or promotes apoptosis in human PAH PAVSMC without affecting non-diseased cells. During the next funding period, we propose to elucidate roles, mechanisms of regulation and function of MST1/2 in PAH, and explore the benefits of targeting MST1/2 signaling to correct mechanistic abnor- malities and reverse PA remodeling and PH. Specifically, we will: (1) critically evaluate roles of MST1 and 2, its interacting partner BUB3 and downstream effector CDC20 in regulating Akt, mTORC1 and Yap/Taz networks, PAVSMC proliferation and survival, pulmonary vascular remodeling and PH using human PAH and non-diseased tissues and PAVSMC and mice with VSM-specific Mst1/2 knockout; (2) determine whether pathological function of MST1/2 in PAH PAVSMC is supported by Akt directly or via Akt-BUB3-Yap/Taz fed-forward loop, and evaluate the role of MST1/2 in ECM remodeling and ECM-dependent proliferation of PAEC and PAAF; and (3) test po- tential benefits of targeting MST1/2 signaling by pharmacological inhibition of MST1/2 kinase, Akt, or (alterna- tively) CDC20 to selectively suppress proliferation, induce apoptosis and reduce pathological ECM production by human PAH PAVSMC, reduce consequent hyper-proliferation of PAEC and PAAF, and reverse experimental pulmonary vascular remodeling and PH. The proposed study will identify a new critical mechanism of pulmonary vascular remodeling and dissect new remodeling-focused molecular target(s) for therapeutic intervention. .