Epigenetic gene repression in pulmonary fibrosis

项目摘要 肺纤维化代表了全世界死亡率增加的原因，尽管经过几十年的研究， 这种疾病如何发生和发展存在相当大的不确定性。虽然多发性纤维化 分子已被发现驱动异常基质沉积，负责维持基质沉积的机制。 持续的和自我维持的纤维形成在很大程度上是未知的。目标锁定机制， 疾病进展过程中成纤维细胞的病理状态可以作为一种有吸引力的治疗策略， 阻止肺纤维化。目前的建议解决的作用，表观遗传基因的抑制，调节成纤维细胞 活化和肺纤维化发展。我们将研究组蛋白3赖氨酸9甲基化的作用 （H3K9me）作为一种重要的表观遗传修饰，其抑制对以下关键基因的转录： 维持或使肺成纤维细胞恢复到抗纤维化或静止的非活性状态。我们的初步数据 证明通过靶向H3K9甲基转移酶G9a或表观遗传修饰抑制H3K9甲基化， reader CBX5有效抑制纤维化刺激引起的成纤维细胞活化。我们的数据表明， G9a和CBX5都直接参与抑制PGC1 β，PGC1 β是线粒体的主要调节因子， 在患病的肺成纤维细胞中代谢显著下调。PGC1 β表达的缺失促进 成纤维细胞活化，而通过表观遗传机制恢复PGC1 β逆转成纤维细胞活化。我们将 使用功能丧失策略来靶向表观遗传调节因子CBX5和G9a，以研究它们的功能。 在活化和静止状态之间转换成纤维细胞的机械作用。利用老鼠遗传学 我们将研究抑制H3K9甲基化在阻止疾病进展中的益处， 博莱霉素诱导的肺纤维化模型。由于我们的初步数据强烈支持抗纤维化功能， PGC1在体外肺成纤维细胞活化过程中起重要作用，在本研究中，我们将进一步研究其抗纤维化作用。 功能，并评估介导其抗纤维化功能的上游和下游转录网络。 综上所述，拟议的研究将揭示关键的表观遗传靶点， 旨在阻止或逆转肺纤维化进展的干预措施。

PROJECT SUMMARY Pulmonary fibrosis represents an increasing cause of mortality worldwide and despite decades of investigation, considerable uncertainty exists as how this disease initiates and progresses. While multiple fibrogenic molecules have been found to drive aberrant matrix deposition, the mechanisms responsible for maintaining persistent and self-sustaining fibrogenesis are largely unknown. Targeting mechanisms that perpetuate the pathological state of fibroblasts during disease progression may serve as an attractive therapeutic strategy to halt lung fibrosis. The current proposal addresses the role of epigenetic gene repression in regulating fibroblast activation and lung fibrosis development. We will investigate the role of histone 3 lysine 9 methylation (H3K9me) as an important epigenetic modification that represses the transcription of genes essential to maintaining or returning lung fibroblasts to an anti-fibrotic or quiescent inactive state. Our preliminary data demonstrate that inhibition of H3K9 methylation by targeting the H3K9 methyltransferase G9a or the epigenetic reader CBX5 potently inhibits fibroblast activation by fibrogenic stimuli. Mechanistically, our data demonstrate that both G9a and CBX5 are directly involved in repressing PGC1, a master regulator of mitochondria metabolism significantly downregulated in diseased lung fibroblasts. Loss of PGC1 expression promotes fibroblast activation, while restoring PGC1 via epigenetic mechanisms reverses fibroblast activation. We will use loss of function strategies to target the epigenetic regulators CBX5 and G9a to investigate their mechanistic roles in switching fibroblasts between activated and quiescence states. Using mouse genetics approaches we will investigate the benefits of inhibiting H3K9 methylation in halting disease progression in bleomycin-induced lung fibrosis models. As our preliminary data strongly support an anti-fibrotic function for PGC1 during lung fibroblast activation in vitro, in this proposal we will further characterize its anti-fibrotic function and evaluate upstream and downstream transcriptional network that mediate its anti-fibrotic functions. Taken together, the proposed research studies will reveal critical epigenetic targets for therapeutic interventions aimed at halting or reversing the progression of pulmonary fibrosis.