Metabolic regulation of fibroblast fate by ATP citrate lyase

项目摘要 特发性肺纤维化(IPF)是一种以进行性积聚为特征的纤维性肺疾病 纤维化细胞外基质(ECM)最终导致广泛的气道重塑，损害肺功能 和呼吸衰竭。细胞外基质产生的主要细胞类型是活化的成纤维细胞。 被称为肌成纤维细胞，其特征是α-SMA表达和产生细胞外基质蛋白，尤其是 胶原蛋白和纤维连接蛋白。我们的实验室先前已经证明幼鼠有能力 自然消解博莱霉素诱导的肺纤维化，肌成纤维细胞群正在接受 细胞凋亡和清除；相反，老年小鼠不能解决与持续性肌成纤维细胞相关的问题 似乎对细胞凋亡有抵抗力的人群。 三磷酸腺苷柠檬酸裂解酶(ACLY)是一种催化柠檬酸转化为乙酰辅酶A的酶，从而 调节乙酰辅酶A的生物利用度和脂肪酸的合成。对公开可用的数据集的询问 提示IPF患者肺组织ACLY基因表达水平降低。我们的初步数据显示 18个月以上的小鼠ACLY的表达也是不足的，当 受到博莱霉素性纤维化的影响。ACLY siRNA在IMR90人成纤维细胞中的下调促进 肌成纤维细胞标志物α-SMA的产生下调AMPK的磷酸化并增强 抗肌成纤维细胞凋亡。该项目提案将检验ACLY缺乏所驱动的假设 并确定ACLY是否是Acly的治疗靶点。 持续性肺纤维化。目的1将研究ACLY在肌成纤维细胞分化过程中的调控，特别是 它与转化生长因子-β的相互作用1.目的2将重点描述ACLY调节细胞凋亡的机制， 尤其是其对AMPK磷酸化的影响。Aim 3将利用基因敲除小鼠模型来 明确检查ACLY缺乏是否是能够维持持续性纤维化的关键纤维化驱动因素。 总的来说，这些研究将阐明ACLY在纤维化形成和未消退的持续性肺纤维化中的作用。 同时也为塞缪尔·史密斯(PI)在 维克多·坦尼卡尔博士的导师，促进了他的专业发展，并促进了他 独立的学术研究。

Project Summary Idiopathic Pulmonary Fibrosis (IPF) is a fibrotic lung disease characterized by progressive accumulation of fibrotic extracellular matrix (ECM) eventually leading to extensive airway remodeling, impaired lung function and respiratory failure. The cell type responsible for the majority of ECM production is an activated fibroblast known as the myofibroblast, characterized by α-SMA expression and production of ECM proteins, particularly collagen and fibronectin. Our laboratory has previously demonstrated that young mice are capable of spontaneously resolving bleomycin induced lung fibrosis, with the myofibroblast population undergoing apoptosis and clearance; in contrast, aged mice fail to resolve in association with a persistent myofibroblast population that appears to be resistant to apoptosis. ATP Citrate Lyase (ACLY) is an enzyme which catalyzes citrate to acetyl CoA conversion, thereby regulating acetyl-CoA bioavailability and fatty acid synthesis. Interrogation of a publicly available dataset indicates that ACLY mRNA levels are reduced in lungs of human subjects with IPF. Our preliminary data shows that ACLY expression in mice aged over 18 months is also deficient and that this expression decreases when subjected to bleomycin induced fibrogenesis. ACLY siRNA knockdown in IMR90 human fibroblasts promotes production of α-SMA, a myofibroblast marker, downregulates phosphorylation of AMPK and enhances myofibroblast apoptosis resistance. This project proposal will test the hypothesis that ACLY deficiency drives myofibroblast apoptosis regulation and determine whether ACLY is a therapeutic target in a mouse model of persistent lung fibrosis. Aim 1 will investigate ACLY regulation during myofibroblast differentiation, particularly its interaction with TGF-β1. Aim 2 will focus describing the mechanism of apoptotic regulation by ACLY, especially on its effects on AMPK phosphorylation. Aim 3 will make use of a genetic knockout mouse model to definitively examine whether ACLY deficiency is a key fibrotic driver capable of sustaining persistent fibrosis. Collectively these studies will elucidate the role ACLY in fibrogenesis and non-resolving persistent lung fibrosis while also serving as the vehicle for a solid foundation of research training for Samuel Smith (PI) under the mentorship of Dr. Victor Thannickal, fostering his professional development and facilitating his pathway to independent academic research.