Role of stromal inflammatory signaling in the aging of lung resident lymphocytes

项目总结 免疫系统功能障碍与几种年龄相关性肺部疾病的发病机制有关。 有趣的是，最近的多项研究发现，组织微环境在脑出血中起着关键作用。 其中一些与年龄相关的免疫系统变化的发病机制。肺间充质提供了一种 为居民免疫系统提供支持的利基市场。因此，要识别与衰老相关的肺部变化 可能导致免疫系统功能障碍的间质，我们进行了单细胞RNA测序 老年小鼠与年轻小鼠肺间充质的比较，确定核因子kappaB(NF-kB)的证据 老年人外膜成纤维细胞相对于年轻外膜成纤维细胞的激活。核因子-kB是炎症和炎症的重要调节因子 细胞衰老，一种多方面的细胞应激反应，其特征包括 永久性细胞周期停滞，细胞周期抑制因子16INK4a的表达，以及已知的复杂分泌模式 作为衰老相关的分泌表型。利用新型p16INK4a报告鼠鉴定细胞 在体内的衰老特征中，我们发现p16INK4a+肺成纤维细胞富含核因子-kB活化和 随着年龄的增长，在实质中积累。因此，研究间充质核因子-kB的激活对大鼠脑缺血再灌注损伤的影响。 为了调节免疫系统，我们使用遗传模型有条件地删除了TNFAIP3，它编码一个 核因子-kB信号的重要负调控因子，来自间充质。本建议书中的初步数据 证实间充质缺失TNFAIP3导致CD8+T细胞在肺内积聚 幼年小鼠的外膜间充质，这些T细胞在转录上类似于与衰老相关的 CD8+T细胞群(TAA)。因此，这一提议的中心假设是核因子-kB的激活 在衰老过程中，成纤维细胞在推动肺内TAA蓄积方面起着直接作用。目标1是确定 利用我们的新型p16INK4a+报告小鼠研究肺成纤维细胞衰老对TAA形成的贡献。目标2 重点是确定间充质核因子-kB驱动TAA形成的机制，目标3将 确定病毒性肺炎背景下TAA形成的功能后果。 为这项提议制定的培训计划是为了实现艾伦博士成为一名 独立内科医生兼科学家研究肺间充质与免疫系统之间的相互作用 在健康和疾病方面。该计划包括正式的教学、会议、指导和实践经验。 通过这一过程，艾伦博士将在细胞衰老、适应性免疫、小鼠模型等方面发展专业知识 肺部感染，肺间充质细胞和相关的上皮干细胞很好，以及负责和 有效的研究实践。她将得到一个强大的导师团队的支持，该团队拥有跨越肺的专业知识 生物学，细胞衰老，组织驻留淋巴细胞，和核因子-kB信号。随着这一职业生涯的结束 发展奖艾伦博士将为理解肺免疫做出宝贵贡献 系统老化，并将做好充分准备，开始她的独立职业生涯。

PROJECT SUMMARY Immune system dysfunction has been implicated in the pathogenesis of several age-related lung diseases. Interestingly, multiple recent studies have identified the tissue microenvironment as playing a critical role in the pathogenesis of some of these age-related immune system changes. The lung mesenchyme provides a supportive niche for the resident immune system. Therefore, to identify aging-related changes in the lung mesenchyme that might contribute to immune system dysfunction, we performed single-cell RNA-sequencing of lung mesenchyme from aged versus young mice, identifying evidence of nuclear-factor kappa-B (NF-kB) activation in aged relative to young adventitial fibroblasts. NF-kB is an important regulator of inflammation and cellular senescence, a multifaceted cellular stress response characterized by several features including permanent cell cycle arrest, expression of the cell cycle inhibitor 16INK4a, and a complex secretory profile known as the senescence-associated secretory phenotype. Using a novel p16INK4a reporter mouse to identify cells with senescent features in vivo, we found that p16INK4a+ lung fibroblasts were enriched for NF-kB activation and accumulated in the parenchyma with age. Therefore, to study the effects of mesenchymal NF-kB activation in regulating the immune system, we used a genetic model to conditionally delete Tnfaip3, which encodes an important negative regulator of NF-kB signaling, from the mesenchyme. Preliminary data in this proposal demonstrates that mesenchymal deletion of Tnfaip3 leads to the accumulation of CD8+ T cells within the lung adventitial mesenchyme of young mice, and that these T cells transcriptionally resemble an aging-associated CD8+ T cell population (Taa). Therefore, the central hypothesis of this proposal is that NF-kB activation within senescent fibroblasts plays a direct role in driving lung Taa accumulation. Aim 1 is to identify the contribution of lung fibroblast senescence to Taa formation using our novel p16INK4a+ reporter mouse. Aim 2 focuses on identifying the mechanism by which mesenchymal NF-kB drives Taa formation, and Aim 3 will determine the functional consequences of Taa formation in the setting of viral pneumonia. The training plan for this proposal has been developed to achieve Dr. Allen’s goal of becoming an independent physician-scientist studying the interactions between the lung mesenchyme and immune system in health and disease. The plan involves formal didactics, conferences, mentorship, and hands-on experience though which Dr. Allen will develop expertise in cellular senescence, adaptive immunity, mouse models of pulmonary infection, the lung mesenchyme and associated epithelial stem cell nice, as well as responsible and effective research practices. She will be supported by a strong mentorship team with expertise spanning lung biology, cellular senescence, tissue resident lymphocytes, and NF-kB signaling. With completion of this Career Development Award Dr. Allen will have made valuable contributions to the understanding of lung immune system aging, and will be well-prepared to launch her independent career.