Crosstalk Between Metabolism and Inflammation in Pulmonary Hypertension

描述(由申请人提供)：炎症过程在血管重塑中起着关键作用，人们越来越认识到这一点。这项建议阐述了炎症的作用，特别是巨噬细胞在以缺氧性形式的肺动脉高压(PH)为特征的血管重塑中的作用。在大多数类型的PH中，观察到巨噬细胞主要聚集在血管的外膜和血管周围区域。大量的初步数据表明，PH血管外膜的成纤维细胞经历了显著的代谢变化，导致细胞内NADH浓度增加，进而激活转录抑制因子C末端结合蛋白1(CtBP1)，CtBP1是一种与NADH具有高结合亲和力的转录氧化还原感受器。CtBP1特异性地抑制包括HMOX-1在内的抗炎基因的表达。这些“激活的”成纤维细胞招募和激活巨噬细胞，主要通过IL6、STAT3、HIF1信号和诱导有氧糖酵解，使巨噬细胞朝着促炎/重塑表型转变。我们认为低氧PH中促炎症的成纤维细胞和成纤维细胞激活的巨噬细胞表型都是由CtBP1驱动的。在缺氧和/或有氧糖酵解的条件下，我们已经证明NADH激活的CtBP1作为转录共抑制因子，并与DNA结合的转录因子和组蛋白修饰酶(HDACs，HMTs)形成复合体。因此，CtBP1将细胞的新陈代谢状态与基因转录的特定协调联系在一起，正如我们已经表明的那样，它在决定细胞行为方面发挥着主导作用。我们现在提出一个新的假设，即CtBP1在PH中驱动成纤维细胞的促炎功能，导致成纤维细胞介导的巨噬细胞激活。成纤维细胞和巨噬细胞相互作用引起的炎症环境导致肺高压和肺血管重构。我们的方法依赖于体外和体内研究，使用来自低氧奶牛、啮齿动物、人类对照组、PH患者和新型转基因小鼠的肺外膜成纤维细胞和原代NA�Ve巨噬细胞。目的1：确定CtBP1在将成纤维细胞“锁定”为促炎表型中的作用。目的：探讨CtBP1在调控成纤维细胞活化巨噬细胞的促炎/促重塑表型中的作用。目的3：确定CtBP1/HO-1信号通路能否在体内以特定细胞类型的方式靶向，预防甚至逆转缺氧性肺高压。我们的研究最终将提供关键数据，以阐明炎症作为原因/贡献者、旁观者的作用，或者它是否或何时只是疾病过程的最终结果。这是促进我们对慢性肺血管疾病的理解的关键一步，以便显著影响PH的临床治疗。

DESCRIPTION (provided by applicant): Inflammatory processes are increasingly appreciated to play a critical role in vascular remodeling. This proposal addresses the role of inflammation, and specifically the role of macrophages in the vascular remodeling that characterize hypoxic forms of pulmonary hypertension (PH). Observations in most forms of PH show that macrophages accumulate primarily in the adventitial and perivascular regions of the vessel. Strong preliminary data demonstrate that fibroblasts resident in the adventitia of PH vessels undergo significant metabolic changes leading to increases in intracellular NADH concentration and subsequent activation of the transcriptional repressor C-terminal binding protein 1 (CtBP1), a transcriptional redox sensor with high binding affinity for NADH. CtBP1 acts specifically to repress expression of anti-inflammatory genes including, hemoxygenase-1 (HMOX-1). These "activated" fibroblasts recruit and activate macrophages toward a pro- inflammatory/remodeling phenotype largely through IL6, STAT3, HIF1 signaling and induction of aerobic glycolysis. We propose that both the pro-inflammatory fibroblast and fibroblast activated macrophage phenotype in hypoxic PH is driven by CtBP1. During hypoxia and/or in conditions of aerobic glycolysis we have shown that NADH-activated CtBP1 acts as a transcriptional co-repressor and complexes with DNA-binding transcription factors and histone modification enzymes (HDACs, HMTs). CtBP1 therefore links the metabolic status of the cell to specific coordination of gene transcription and, as we have shown, exerts a dominant role in determining cell behavior. We now address the novel hypothesis that CtBP1 drives the pro-inflammatory functions of fibroblasts in PH, leading to fibroblast-mediated macrophage activation. The inflammatory environment, caused by the interaction of fibroblasts and macrophages, leads to PH and pulmonary vascular remodeling. Our approach relies on in vitro and in vivo studies using lung adventitial fibroblasts and primary na�ve macrophages from hypoxic cows, rodents, and human controls and PH patients, and novel genetically modified mice. AIM 1: Determine the role of CtBP1 in "locking" the fibroblast into a pro-inflammatory phenotype. AIM 2: Determine the role of CtBP1 in controlling the pro-inflammatory/pro-remodeling phenotype of fibroblast-activated macrophages. AIM 3: Determine whether CtBP1/HO-1 signaling can be targeted in a cell-type-specific manner in vivo to prevent or even reverse hypoxia-induced PH. Our investigations will ultimately provide key data in elucidating the role of inflammation as a cause/contributor, a bystander, or whether or when it is simply the end result of the disease process. This is a critica step to advance our understanding of chronic pulmonary vascular disease in order to significantly impact the clinical management of PH.