Role of ATII cell senescence in influenza pathogenesis in aging

ATII细胞衰老在流感发病机制中的作用

• 批准号: 10741215
• 负责人: IAN CHRISTOPHER DAVIS
• 金额: $ 44.83万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10741215
• 关键词: Activities of Daily Living; Acute; Acute Respiratory Distress Syndrome; Age; Aging; Alveolar; Animals; Antiviral Agents; Attenuated; Biological Assay; Biology; Biophysics; C57BL/6 Mouse; Calorimetry; Cell Aging; Cell Energetics; Cell Separation; Cell physiology; Cells; Cellular Metabolic Process; Cessation of life; Chronic Obstructive Pulmonary Disease; Cytidine Diphosphate Choline; Development; Disease; Distal; Elderly; Energy Metabolism; Ensure; Equipment; Functional disorder; Gases; Genes; Glycolysis; Goals; Hypoxemia; Immune response; Inbred BALB C Mice; Infection; Inflammation; Influenza; Influenza A Virus, H1N1 Subtype; Influenza A virus; Influenza vaccination; Ion Transport; Lecithin; Lipids; Liquid substance; Lower respiratory tract structure; Lung; Lung diseases; Maintenance; Metabolic; Metabolic Clearance Rate; Metabolism; Methods; Mitochondria; Modeling; Mus; Non-Small-Cell Lung Carcinoma; Outcome; Oxidative Phosphorylation; PET/CT scan; Pathogenesis; Pathway interactions; Phospholipids; Physiological; Physiology; Population; Process; Production; Proteins; Public Health; Pulmonary Inflammation; Recycling; Reproducibility; Research Personnel; Resources; Respiratory Disease; Role; Severities; Site; Surface Tension; Testing; Viral Pathogenesis; Virus Diseases; Virus Replication; Western Blotting; X-Ray Computed Tomography; age effect; airway epithelium; alveolar type II cell; experimental study; extracellular; flexibility; glucose uptake; improved; in vivo; influenza epidemic; influenza infection; influenza virus vaccine; insight; mouse model; normal aging; novel; older patient; patient subsets; pulmonary function; seasonal influenza; senescence; success; surfactant; surfactant production; therapeutic target; vaccine access; vaccine efficacy

Alveolar type II (ATII) cells synthesize, secrete, and recycle surfactant proteins and lipids and regulate alveolar lining fluid depth by alveolar fluid clearance. Because both processes require large amounts of energy, ATII cells contain large numbers of mitochondria and mainly generate ATP by oxidative phosphorylation (OXPHOS). ATII cells are the primary site for influenza A virus (IAV) replication in the distal lung and central players in the pathogenesis of IAV-induced ARDS. Importantly, the elderly are over-represented in influenza-related fatalities. However, there is limited understanding of the impact of either aging or IAV infection on ATII cell function, senescence, and energy metabolism. ATII cells isolated from lungs of young (2-3 month-old) C57BL/6 mice primarily generate ATP by OXPHOS. In contrast, preliminary studies show ATII cells from aging (27 month-old) mice undergo a glycolytic shift and downregulate OXPHOS, possibly as a result of senescence. IAV infection of young mice causes a glycolytic shift and a decrease in OXPHOS which is reversed by CDP- choline treatment, resulting in a net increase in total ATP production, attenuated hypoxemia, and reduced pulmonary inflammation. IAV infection of aging mice causes more severe hypoxemia and further reduces OXPHOS without any compensatory increase in glycolysis, resulting in a net decrease in total ATP production despite the increased energy demands imposed by viral replication. Hence, it is hypothesized that influenza is more severe in the elderly because IAV infection imposes additional energetic demands for viral replication on ATII cells that lack inherent metabolic flexibility due to aging-associated senescence. By inhibiting de novo phospholipid synthesis, IAV also induces further mt dysfunction. Together, these effects provoke an energy crisis and render ATII cells unable to perform their normal physiologic functions (alveolar fluid clearance and surfactant synthesis), which results in progression to ARDS. It is further proposed that CDP- choline treatment improves OXPHOS in ATII cells and increases their functional capacity, thereby improving influenza outcomes. This hypothesis will be tested in two Specific Aims. Aim 1 will use a robust, reproducible, and relevant model of IAV-induced ARDS in 21-24 month-old C57BL/6 and BALB/c mice to define effects of aging, IAV infection, and CDP- choline treatment on ATII cell physiologic functions (surfactant production and alveolar fluid clearance), whole body metabolism (by open circuit calorimetry), lung glucose uptake (by PET/CT), lung inflammation, and viral replication. Aim 2 will use a comprehensive battery of flow cytometric assays and Western blot to quantify the level of senescence in ATII cells isolated from the lungs of mock- and IAV-infected young and aging mice and will analyze the impact of aging, IAV infection, and CDP-choline treatment on ATII cell energetics by extracellular flux analysis. Proposed experiments will provide novel mechanistic insights into the contribution of ATII cell dysfunction and senescence to development of more severe influenza in the elderly and will generate fundamental new information relevant to many pulmonary diseases of aging, such as COPD, IPF, and non-small cell lung cancer.

牙槽II型（ATII）细胞合成，分泌和回收表面活性剂蛋白和脂质，并调节牙槽内膜液 深度通过肺泡流体清除率。因为这两个过程都需要大量的能量，所以ATII单元格包含大量 线粒体的含量，主要是通过氧化磷酸化（OXPHOS）产生ATP。 ATII单元是 IAV诱导的ARD的发病机理中远端肺和中心参与者中的流感病毒（IAV）复制。 重要的是，老年人在与流感相关的死亡人数中的人数过多。但是，对 衰老或IAV感染对ATII细胞功能，衰老和能量代谢的影响。从中分离出的Atii细胞 年轻（2-3个月大）C57BL/6小鼠的肺主要由Oxphos产生ATP。相反，初步研究表明 衰老（27个月大）小鼠的ATII细胞经历糖酵解的转移并下调Oxphos，可能是由于 衰老。年轻小鼠的IAV感染会导致糖酵解转移和Oxphos的降低，这被CDP逆转 胆碱治疗，导致总ATP产生净增加，低氧血症减弱和肺部降低 炎。衰老小鼠的IAV感染会导致更严重的低氧血症，并进一步降低OXPHOS而没有任何 糖酵解的补偿性增加，尽管能量增加，但总ATP产生的净减少 病毒复制施加的需求。因此，假设流感在老年人中更为严重，因为IAV 感染对缺乏固有代谢灵活性的ATII细胞施加了对病毒复制的额外精力需求 由于衰老相关的衰老。通过抑制从头磷脂的合成，IAV还诱导进一步的MT功能障碍。 这些效果共同引起了能源危机，并使ATII细胞无法执行其正常的生理功能 （肺泡流体清除率和表面活性剂合成），导致ARDS的发展。进一步提出CDP- 胆碱治疗可改善ATII细胞的OXPHOS并提高其功能能力，从而改善流感 结果。该假设将以两个具体的目的进行检验。 AIM 1将使用强大，可重现和相关模型 IAV诱导的21-24个月大的C57BL/6和BALB/C小鼠的ARD，以定义衰老，IAV感染和CDP-的影响 ATII细胞生理功能（表面活性剂产生和牙槽液清除率）的胆碱治疗，全身 代谢（通过开路量热法），肺葡萄糖摄取（通过PET/CT），肺部炎症和病毒复制。目的 2将使用全面的流式细胞术测定和蛋白质印迹来量化ATII中的衰老水平 从模拟和IAV感染的年轻小鼠和衰老小鼠的肺中分离出来的细胞，将分析衰老，IAV的影响 通过细胞外通量分析对ATII细胞能量的感染和CDP-胆碱治疗。建议的实验将 提供有关ATII细胞功能障碍和衰老对更多更多的贡献的新型机械见解 老年人的严重流感，将产生与许多肺部疾病有关的基本新信息 衰老，例如COPD，IPF和非小细胞肺癌。