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: 10662520
• 负责人: Cedric G Geoffroy
• 金额: $ 37.46万
• 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/10662520
• 关键词: Acute; Age; Aging; Animals; Astrocytes; Biological; Biological Assay; Biology; 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; Membrane Potentials; Mitochondria; Molecular; Molecular Biology; Mus; Neurons; Nuclear; Oxidative Phosphorylation; PIAS3 Gene; Pathway interactions; Persons; Pharmaceutical Preparations; Phosphorylation; Play; Population; Recovery; Recovery of Function; Reporting; Role; STAT protein; STAT3 gene; Signal Transduction; Site; Sorting; Spinal; Spinal Injections; Spinal Injuries; Spinal cord injury; System; Testing; Tissues; Transgenic Mice; Translating; United States; Vertebral column; Western Blotting; Work; age related; aged; aging population; astrogliosis; cell type; functional decline; gain of function; improved; in vivo; inflammatory marker; loss of function; mRNA Expression; mRNA delivery; middle age; mitochondrial dysfunction; mitochondrial membrane; neural; neuroprotection; normal aging; overexpression; pharmacologic; pre-clinical therapy; 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).

项目概要 在美国，每年新增脊髓损伤 (SCI) 病例超过 17,000 例，约 30 万人 迄今为止，FDA 批准的治疗方法尚无能日益改善 SCI 的功能恢复。 发生在人口老龄化中，伴随着年龄依赖性的恢复下降。 将年龄作为关键生物学变量的研究已成为临床前转化的主要障碍 成功治疗老龄化 SCI 人群的疗法。 与正常衰老相关的线粒体功能下降表明，改善线粒体功能 SCI 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，可能会产生不同的影响，损害年轻小鼠的恢复，而 虽然这种年龄依赖性效应的细胞和分子介质尚不清楚， 这表明，通过针对线粒体功能的下降，可以实现更一致的效果。 新数据表明星形胶质细胞的线粒体活性随着年龄的增长而受损。 体外降低年轻星形胶质细胞的线粒体活性会增加损伤程度，相反，激活 线粒体缩小了病变大小，这一点非常重要，因为急性星形胶质细胞疤痕形成后。 SCI 是有益的，可以减少炎症的扩散并初步保护体内神经组织。 数据表明，随着年龄的增长，急性星形胶质细胞疤痕的形成减少，炎症标志物增加 和病变大小，与功能恢复的减少相关。值得注意的是，试点数据显示年龄- 参与星形胶质细胞增生的分子途径的依赖性变化，包括 STAT3 的减少（信号 转导子和转录激活子）和 PIAS3（激活的 STAT3 的蛋白质抑制剂）的增加，两者 对线粒体活动具有相反的作用。 因此，中心假设是星形胶质细胞线粒体功能的年龄依赖性下降 随着年龄的增长，损伤星形胶质细胞疤痕形成并减少 SCI 后的功能恢复。 在三个相关但独立的目标中进行测试： 该项目的总体目标是证明促进星形胶质细胞中的线粒体活性可以减少 损伤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。 利用遗传 (Ndufs4flox;Ai14) 和药理学研究体外和体内星形胶质细胞的线粒体功能 策略（目标 1），通过使用星形胶质细胞中的 PGC-1α 过度表达和药物来增加线粒体活性 促进从新的高内涵筛选测定（目标 2）中选择的线粒体功能，并通过建立 STAT3 和 PIAS3 在调节星形胶质细胞线粒体功能中发挥的亚细胞作用 体外和体内功能的获得和丧失（转基因小鼠 STAT3flox、PIAS3flox、SOCS3flox；过度表达 核或线粒体 STAT3 和 PIAS3）以及 SCI 后体内瞬时 mRNA 表达（目标 3）。