Lung-Protective Mechanisms of Metformin in TB

项目总结 由结核分枝杆菌(Mtb)引起的结核病(TB)仍然是全球主要的健康威胁。 延长抗菌药物方案的依从性和毒性以及增加耐药性的挑战 强调需要新的治疗方法。宿主定向治疗(HDT)利用宿主固有的 小分子药物加速绝育和限制宿主肺损伤的作用机制 豁免权。我们报告了二甲双胍降低结核分枝杆菌感染患者的肺部细菌负荷和免疫病理。 老鼠。对50多万接受二甲双胍治疗的糖尿病患者的回顾性数据支持 这种药物的HDT潜力。这些研究报告了较低的结核分枝杆菌感染率和从潜伏期到 活动性肺结核、更少的空化和全因死亡率、更快的痰转和更少的结核病复发。 该项目的目标是了解二甲双胍HDT的疗效机制，重点是炎症。 和纤维化症。我们的初步数据表明，二甲双胍可以扩增非经典的Ly6Clo单核细胞 AMPK依赖方式。这些细胞对于先天“训练”免疫中的宿主保护是必不可少的，它们 参与组织修复。Ly6Clo单核细胞产生CXCL10，招募CD8+CXCR3+Memory(TM)细胞， 其可以抗原特异性和非特异性方式限制结核分枝杆菌复制。我们的数据还表明， 二甲双胍介导的保护涉及缺口通路的调制，并抑制NOTCH1 推动纤维化和增强NOTCH2，以调节Ly6Clo单核细胞和CD8+TM细胞的分化。 目标1中的实验将确定保护中对AMPK和NOTCH信令的要求 应用小鼠结核气雾剂模型研究二甲双胍的作用。结果是肺部细菌载量，免疫 病理、肺组织损伤与胶原重塑、转录和蛋白质组学标志 纤维化。二甲双胍的免疫代谢和表观遗传调节活性将在 结核病-人类发展疗法的背景。AIM 2的实验将确定CD8+TM细胞和CXCL10- CXCR3轴在宿主保护中的作用，并评估二甲双胍和 培养的CD8+TM细胞和虚拟记忆T细胞。这两个目标都包括使用替代方案进行验证研究 小鼠模型(C3HeB/FEJ和Collaborative Cross)和去识别人血浆、血RNA和 来自临床结核病研究的PBMC样本，参与者使用或不使用二甲双胍。这个项目 将产生关于二甲双胍TB-HDT疗效机制的新知识，这将支持该设计 和解释使用二甲双胍的人类临床试验，并可能确定HDT药物的新靶点 比二甲双胍具有更强的特异性、有效性和耐受性。

PROJECT SUMMARY Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains a major global health threat. Challenges of compliance and toxicities of prolonged antimicrobial regimens and increasing drug resistance highlight the need for novel treatment approaches. Host-directed therapy (HDT) harnesses host-intrinsic mechanisms using small molecule drugs to accelerate sterilization and limit lung damage caused by host immunity. We reported that metformin reduced lung bacterial load and immune pathology in Mtb-infected mice. Retrospective data from over half a million individuals treated for diabetes with metformin support the HDT potential of this drug. These studies reported lower rates of Mtb infection and progression from latent to active TB, less cavitation and all-cause mortality, accelerated sputum conversion and less TB recurrence. The goal of this project is to discern the mechanisms of metformin HDT efficacy, focusing on inflammation and fibrosis. Our preliminary data suggest that metformin expands non-classical Ly6Clo monocytes in an AMPK-dependent manner. These cells are essential for host protection in innate “trained” immunity and they participate in tissue repair. Ly6Clo monocytes produce CXCL10 that recruits CD8+CXCR3+ memory (TM) cells, which may restrict Mtb replication in an antigen-specific and non-specific manner. Our data also suggest that metformin-mediated protection involves NOTCH pathway modulation, with suppression of NOTCH1 that drives fibrosis and enhancement of NOTCH2 to regulates Ly6Clo monocyte and CD8+ TM cell differentiation. Experiments in Aim 1 will establish the requirement for AMPK and NOTCH signaling in the protective functions of metformin using the mouse aerosol TB model. Outcomes are lung bacterial load, immune pathology, lung tissue damage with collagen remodeling and transcriptomic and proteomic markers of fibrogenesis. Immunometabolic and epigenetic regulatory activities of metformin will be investigated in the context of TB-HDT. Experiments in Aim 2 will establish the requirements for CD8+ TM cells and the CXCL10- CXCR3 axis in host protection and evaluate potential similarities and differences between metformin- educated CD8+ TM cells and virtual memory T cells. Both Aims include validation studies using alternative mouse models (C3HeB/FeJ and Collaborative Cross) and de-identified human plasma, blood RNA and PBMC samples from clinical TB studies having participants with or without metformin exposure. This project will produce new knowledge about the mechanisms of metformin TB-HDT efficacy that will support the design and interpretation of human clinical trials using metformin and might identify new targets for HDT agents having greater specificity, efficacy and tolerability than metformin.