Lung Endothelial Cell Apoptosis and Emphysema

描述（由申请人提供）： 吸烟（CS）是COPD的主要原因，是美国第四大死亡原因。CS诱导的氧化应激导致内皮细胞（EC）凋亡，越来越多的证据表明肺泡壁细胞凋亡在肺气肿的发生发展中起作用。本研究的总体目标是了解CS诱导肺EC凋亡和肺气肿的机制。我们以前对小GTP酶羧甲基化的研究表明，RhoA GTP酶活性的抑制导致粘着斑复合物（FAC）的破坏和肺EC凋亡。我们目前的初步数据表明，CS提取物（CSE）通过氧化应激破坏FAC，导致EC凋亡，并降低RhoA活性。目的1：我们将确定氧化剂介导的RhoA失活是否导致CSE诱导的FAC丧失和肺EC凋亡。我们以前的研究也表明，当ER分子伴侣减少时，尽管未折叠蛋白反应（UPR）被激活，EC凋亡也会发生。我们的初步数据表明，CSE激活UPR组分eIF2a，其在暴露于CS的小鼠的肺气肿肺中也被激活。目的2：我们将确定UPR是否在CSE暴露后首先被激活，并在肺EC中长期氧化应激后最终有缺陷。自噬是一种保护性过程，其标志物已在COPD患者的肺中得到证实。我们的初步数据表明，暴露于CSE的肺内皮细胞和暴露于CS的小鼠肺中自噬标志物的表达增加。目的3：我们将确定自噬是否在CSE暴露后被激活，并在肺EC中长期氧化应激后最终有缺陷。这些研究将加深对肺气肿发病机制的理解，并可能导致这种毁灭性疾病的新治疗方法的发展。

DESCRIPTION (provided by applicant): Cigarette smoke (CS) is the primary cause of COPD, the fourth leading cause of death in the US. CS-induced oxidant stress causes endothelial cell (EC) apoptosis, and there is growing evidence that apoptosis of alveolar wall cells plays a role in the development of emphysema. The overall objective of this proposal is to understand mechanisms of CS-induced lung EC apoptosis and emphysema. Our previous studies on carboxylmethylation of small GTPases indicated that inhibition of RhoA GTPase activity causes focal adhesion complex (FAC) disruption and lung EC apoptosis. We present preliminary data indicating that CS extract (CSE) disrupts FAC via oxidative stress, causes EC apoptosis, and decreases RhoA activity. Aim 1: We will determine if oxidant- mediated RhoA inactivation causes CSE-induced loss of FAC and apoptosis of pulmonary EC. Our previous studies also demonstrated that EC apoptosis occurs despite activation of the unfolded protein response (UPR) when ER molecular chaperones are decreased. Our preliminary data indicate that CSE activates a UPR component, eIF2a, which was also activated in emphysematous lungs of mice exposed to CS. Aim 2: We will determine if UPR is first activated upon CSE exposure and ultimately defective after prolonged oxidative stress in pulmonary EC. Autophagy is a protective process, markers of which have been demonstrated in lungs of COPD patients. Our preliminary data demonstrate increased expression of autophagy markers in lung endothelial cells exposed to CSE and in lungs of mice exposed to CS. Aim 3: We will determine if autophagy is activated upon CSE exposure and ultimately defective after prolonged oxidative stress in pulmonary EC. The proposed studies will enhance understanding of the pathogenesis of emphysema and may result in develop of new therapeutic approaches to this devastating disease.