Understanding the age-dependent mitochondrial function in astrocytes after spinal cord injury via bi-directional manipulation of activity

通过双向操纵活性了解脊髓损伤后星形胶质细胞的年龄依赖性线粒体功能

• 批准号: 10503483
• 负责人: Cedric G Geoffroy
• 金额: $ 37.48万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10503483
• 关键词: Acute; Age; Aging; Animals; Astrocytes; Biological; Biological Assay; Biology of Aging; Cell Death; Cells; Chronic; Cicatrix; Data; FDA approved; Fractionation; Genetic; Genetic Transcription; Goals; Histocytochemistry; Impairment; In Vitro; Inflammation; Injections; Injury; Lesion; Measures; Mediating; Mediator of activation protein; Membrane Potentials; Mitochondria; Molecular; Molecular Biology; Mus; Neurons; Nuclear; Oxidative Phosphorylation; PIAS3 Gene; Pathway interactions; Persons; Pharmaceutical Preparations; Pharmacology; Play; Population; Proteins; Recovery; Recovery of Function; Reporting; Role; STAT protein; STAT3 gene; Signal Transduction; Site; Sorting - Cell Movement; Spinal; Spinal Injections; Spinal Injuries; Spinal cord injury; System; Testing; Tissues; Transgenic Mice; Translating; United States; Western Blotting; Work; age effect; age related; aged; aging population; astrogliosis; cell type; functional decline; improved; in vivo; inflammatory marker; loss of function; mRNA Expression; mRNA delivery; middle age; mitochondrial dysfunction; mitochondrial membrane; neuroprotection; normal aging; overexpression; pre-clinical therapy; relating to nervous system; response to injury

Project Summary In the United States, there are >17,000 new cases of spinal cord injury (SCI) every year, and ~300,000 people living with chronic SCI. To date, no FDA-approved treatment improves functional recovery. SCI is increasingly occurring in the aging populations, accompanied by an age-dependent decline in recovery. However, the lack of studies that incorporate age as a key biological variable has become a major obstacle in translating preclinical therapies into successfully treating the aging SCI population. The functional decline of mitochondria associated with normal aging suggests that improving mitochondrial function following SCI could result in better recovery. However, non-selectively enhancing mitochondria activity can have divergent effects depending on age and effected cell types, impairing recovery in young mice while promoting it in older mice. While the cellular and molecular mediators of this age-dependent effect are unknown, this suggests that more uniform effects may be achieved by targeting the decline in mitochondria function in a cell specific manner. New data suggest that mitochondrial activity in astrocytes is impaired with age, and that in vitro reducing mitochondrial activity in young astrocytes increases the injury size, and conversely, activation of mitochondria reduces the lesion size. This is of high importance because acute astroglial scar formation after SCI is beneficial, reducing the spread of inflammation and protecting spared neural tissue. Preliminary in vivo data suggests a reduction in acute astroglial scar formation with age and an increase in inflammation markers and lesion size, associated with a reduction in functional recovery. Remarkably, pilot data show an age- dependent changes in molecular pathways involved in astrogliosis including the reduction of STAT3 (signal transducer and activator of transcription) and increase of PIAS3 (Protein inhibitor of activated STAT3), both having opposite roles on mitochondrial activities. Thus, the central hypothesis is that the age-dependent decline in astrocytic mitochondrial functions impairs astroglial scar formation and reduces functional recovery after SCI with age. This hypothesis will be tested in three related, but independent, aims: The overall objective of this project is to demonstrate that promoting mitochondrial activity in astrocytes reduces lesion size and promotes recovery after SCI in aged animals. These objectives will be achieved by reducing mitochondrial function in astrocytes in vitro and in vivo, using genetic (Ndufs4flox;Ai14) and pharmacological strategies (Aim 1), by increasing mitochondrial activity using PGC-1α overexpression in astrocytes and drugs promoting mitochondrial functions chosen from a new High Content Screen assay (Aim 2), and by establishing the sub-cellular roles played by STAT3 and PIAS3 in modulating mitochondrial function in astrocytes using in vitro and in vivo gain and loss of function (transgenic mice STAT3flox, PIAS3flox, SOCS3flox; overexpression of nuclear or mitochondrial STAT3 and PIAS3) and in vivo transient mRNA expression after SCI (Aim 3).

项目摘要 在美国，每年有> 17,000例新的脊髓损伤（SCI），约30万人 与慢性科幻一起生活。迄今为止，未经FDA批准的治疗可改善功能恢复。 SCI越来越多 发生在老龄化人群中，是由于年龄依赖的恢复而实现的。但是，缺乏 将年龄作为关键生物变量的研究已成为翻译临床前的主要障碍 疗法成功治疗老龄化的SCI人群。 线粒体与正常衰老相关的功能下降表明，线粒体改善 SCI之后的功能可能会导致更好的恢复。但是，非选择性增强线粒体活性 根据年龄和受影响的细胞类型，可能产生不同的作用，损害了年轻小鼠的恢复 在老鼠中促进它。虽然这种依赖年龄依赖性效应的细胞和分子介质尚不清楚，但 这表明可以通过靶向线粒体功能下降来实现更多均匀的影响 细胞特定方式。新数据表明，星形细胞中的线粒体活性会随着年龄的增长而受损，并且 体外减少年轻星形胶质细胞中的线粒体活性会增加损伤的大小，相反，激活 线粒体降低了病变的大小。这是很重要的，因为急性星形胶质疤痕形成 SCI是有益的，可减少炎症的传播和保护较不幸的神经组织。体内初步 数据表明，随着年龄的增长，急性星形胶质疤痕形成和炎症标记增加 和病变大小，与功能恢复的减少有关。值得注意的是，飞行员数据显示了一个年龄 星形胶质病涉及的分子途径的依赖变化，包括降低STAT3（信号 转录的换能器和激活剂）和PIAS3的增加（激活STAT3的蛋白质抑制剂），两者都 在线粒体活动中具有相反的作用。 这是中心假设是星形细胞线粒体功能的年龄依赖性下降 会损害星形胶质疤痕的形成并减少SCI随年龄后的功能恢复。这个假设将会 在三个相关但独立的目标中进行测试： 该项目的总体目的是证明促进星形胶质细胞中的线粒体活性会减少 病变的大小并促进老年动物SCI后的恢复。这些目标将通过减少来实现 体外和体内星形胶质细胞的线粒体功能，使用遗传（NDUFS4FLOX； AI14）和药物 策略（AIM 1），通过使用PGC-1α过表达在星形胶质细胞和药物中增加线粒体活性 从新的高内容屏幕分析（AIM 2）中促进线粒体功能，并通过建立 STAT3和PIAS3在使用In中调节星形细胞中的线粒体功能中扮演的亚细胞角色 体外和体内功能的增益和丧失功能（转基因小鼠Stat3flox，pias3flox，socs3flox;过表达 SCI后的核或线粒体STAT3和PIAS3）和体内短暂mRNA表达（AIM 3）。