Molecular clock dysfunction in lung cellular senescence by environmental tobacco smoke

总结 环境烟草烟雾（ETS）或“二手烟”暴露导致压力引起的不良反应。 结果包括细胞衰老和与全身性 损伤和炎症。我们最近报道，ETS扰乱生物钟 功能，诱导氧化应激和刺激异常炎症反应。REV-ERBα是一个关键的 分子钟的组成部分，调节核心时钟基因的表达，促炎和 促衰老介质。我们的初步数据表明，ETS介导的细胞衰老是 依赖于肺中时钟基因核受体REV-ERB受体的不规则活性。我们的初步 数据进一步显示，在分子钟缺陷型REV-ERBα中， KO小鼠，表明时钟蛋白REV-ERB β参与调节DNA损伤/修复。 此外，REV-ERBα激动剂可降低ETS诱导的促炎和促衰老介质水平。 然而，分子钟功能障碍在慢性ETS介导的DNA损伤/修复、细胞凋亡和细胞凋亡中的作用尚不清楚。 衰老和毒理学影响仍然未知。Sirtuin 1（SIRT 1）是一种蛋白质/组蛋白脱乙酰酶， 由于ETS的减少，导致细胞衰老、氧化应激和异常炎症反应。我们 初步数据显示SIRT 1调节REV-ERBα丰度。然而，尚不清楚SIRT 1是否 通过REV-ERBα依赖性机制调节肺细胞衰老和炎症反应。 我们假设ETS破坏了分子钟功能，特别是REV-ERBα丰度，导致 肺毒性中DNA损伤通过SIRT 1依赖性机制引发细胞衰老我们 我建议通过确定ETS诱导的REV-ERB受体阻断对细胞增殖的影响来检验这一假设。 衰老、DNA损伤/修复和毒理学反应的小鼠模型，基于以下三个方面 目的：目的1：确定ETS介导的REV破坏的分子机制。 ERB介导分子时钟功能导致细胞衰老和衰老相关炎症 目的2：确定REV-ERB介导的非同源末端DNA修复 目的3：确定SIRT 1在ETS暴露后细胞衰老过程中的作用， 调节ETS后REV-ERB凋亡和DNA损伤诱导的肺细胞衰老。 这一提议的结果将揭示分子钟在调节DNA损伤诱导中的作用。 肺细胞衰老通过SIRT 1依赖机制在异生素反应ETS曝光。 反过来，我们的发现将对药物治疗的发展具有巨大的转化潜力 基于靶向分子时钟功能，以改善肺细胞衰老和DNA损伤， 长期暴露于ETS

SUMMARY Environmental tobacco smoke (ETS) or “secondhand smoke” exposure leads to stress-induced adverse outcomes including cellular senescence and toxicological effects on the lungs associated with systemic injury and inflammation in airway disorders. We have recently reported that ETS disrupts circadian clock function, induces oxidative stress and stimulates abnormal inflammatory responses. REV-ERBα is a critical component of the molecular clock, which regulates the expression of core clock genes, pro-inflammatory and pro-senescent mediators. Our preliminary data suggest that ETS-mediated cellular senescence is dependent on irregular activity of the clock gene nuclear receptor REV-ERB in the lungs. Our preliminary data further show an impaired DNA repair and inflammatory response in molecular clock deficient REV-ERBα KO mice, suggesting the involvement of the clock protein REV-ERB in regulating DNA damage/repair. Further, REV-ERBα agonists reduce ETS-induced levels of pro-inflammatory and pro-senescent mediators. However, the role of molecular clock dysfunction in chronic ETS-mediated DNA damage/repair, cellular senescence, and toxicological effects remains unknown. Sirtuin 1 (SIRT1), a protein/histone deacetylase, is reduced by ETS, resulting in cellular senescence, oxidative stress and abnormal inflammatory responses. Our preliminary data show that SIRT1 regulates REV-ERBα abundance. However, it is not known whether SIRT1 regulates lung cellular senescence and inflammatory responses through a REV-ERBα-dependent mechanism. We hypothesize that ETS disrupts molecular clock function, specifically REV-ERBα abundance, resulting in DNA damage-initiated cellular senescence through a SIRT1-dependent mechanism in pulmonary toxicity. We propose to test this hypothesis by determining the impact of ETS-induced REV-ERBdisruption on cellular senescence, DNA damage/repair, and toxicological responses in a mouse model based on the following three Aims: Aim 1: Determine the molecular mechanism through which ETS-mediated disruption of REV- ERBmolecular clock function leads to cellular senescence and senescence-associated inflammatory phenotype (SASP); Aim 2: Determine the involvement of REV-ERB in DNA repair by non-homologous end joining (NHEJ) during cellular senescence following ETS exposure; and Aim 3: Determine the role of SIRT1 in regulating REV-ERB and DNA damage-induced lung cellular senescence following ETS. The outcome of this proposal will unravel the role of the molecular clock in regulating DNA damage-induced lung cellular senescence via a SIRT1-dependent mechanism during the xenobiotic response to ETS exposure. In turn, our findings will have great translational potential for the development of pharmacological therapies based on targeting molecular clock function to ameliorate lung cellular senescence and DNA damage following chronic exposure to ETS.