Control of Muscle Stem Cells to Enhance Regeneration

控制肌肉干细胞以增强再生

基本信息

批准号：
10346767
负责人：
Helen M Blau
金额：
$ 48.53万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-02-01 至 2026-11-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10346767
关键词：
3&apos Untranslated Regions Affect Age Aging American Architecture Biological Assay Blocking Antibodies CD36 Antigens CD47 gene Cell Count Cell physiology Cell surface Cells Censuses Cyclic AMP Cytometry Data Defect Detection Elderly Exhibits Functional disorder Generations Genetic Transcription Goals Heterogeneity Homeostasis Impairment Incidence Injury Institutionalization Investigation Kinetics Knowledge Lead Long-Term Care Maps Measurement Molecular Movement Mus Muscle Muscle function Muscle satellite cell Muscular Atrophy Natural regeneration Outcome Phenotype Polyadenylation Population Population Heterogeneity Post-Transcriptional Regulation Proteins Public Health Quality of life Regenerative capacity Regenerative response Research Resolution Series Signal Transduction Skeletal Muscle Surface THBS1 gene Technology Therapeutic Therapeutic Intervention Thrombospondin 1 Tissue imaging Tissues Transcript Up-Regulation age related age-related muscle loss aged data integration falls frailty improved in vivo in vivo evaluation indexing innovation insight muscle aging muscle form muscle regeneration muscle strength neutralizing antibody novel novel strategies novel therapeutic intervention novel therapeutics p38 Mitogen Activated Protein Kinase paracrine prevent prospective receptor regeneration model regenerative repaired sarcopenia self-renewal single cell technology single-cell RNA sequencing skeletal muscle wasting stem cell aging stem cell expansion stem cell function stem cell niche stem cell population tool transcriptome sequencing

项目摘要

PROJECT SUMMARY According to the most recent U.S. Census, the elderly population will more than double to 80 million, encompassing 1 in 5 Americans by 2050. Aging is characterized by a decline in tissue function and regenerative capacity. Sarcopenia, also known as age-dependent loss of skeletal muscle mass and strength, is a major public- health problem that affects 15% of the elderly, leading to loss of mobility and diminished quality of life. Age- related muscle loss is paralleled by a loss in the function of muscle stem cells (MuSCs), key players in muscle homeostasis and regeneration. However, the mechanisms responsible for age-associated MuSC dysfunction remain elusive. Two major barriers to gaining mechanistic insights into MuSC aging are (1) the heterogeneity of the aged MuSC population, which renders standard bulk analysis ineffective, and (2) the lack of tools to resolve this heterogeneity, underscoring the need for single-cell studies. We previously demonstrated that aged MuSCs are a heterogeneous population comprised of functional and dysfunctional subsets. This key observation suggests a therapeutic strategy to regenerate muscle - boosting the activity of resilient functional MuSCs. Here we explore this possibility using a specific cell surface marker and a series of innovative single-cell technologies required to resolve MuSC subsets. Our preliminary data iden- tify CD47 as a cell surface marker whose expression level, not presence or absence, distinguishes functional CD47lo and dysfunctional CD47hi MuSC subsets. Known widely as a receptor for SIRPα, CD47 is also a receptor for thrombospondin-1 (THBS1). We found that CD47hi MuSCs accumulate in aged muscle and aberrantly ex- press THBS1. We hypothesize that during aging the accumulation of CD47hi MuSCs impairs the proliferation of CD47lo MuSCs through secretion of THBS1, hindering regeneration and contributing to sarcopenia. Here, our specific aims are to (1) determine how CD47 signaling goes awry in aging, (2) elucidate how post-transcriptional regulation of CD47 is altered during aging leading to the accumulation of dysfunctional CD47hi MuSCs, and (3) determine the effects of aberrant THBS1 secretion in the aged MuSC niche on regeneration. We capitalize on cutting-edge single-cell technologies, including multidimensional single-cell mass cytometry (CyTOF) and multi- plexed tissue imaging (CO-Detection by indexing (CODEX)). These technologies allow us to track simultane- ously 40+ distinct cell and signaling phenotypes in CD47lo and CD47hi MuSCs (CyTOF) and resolve how spatial changes in the architecture of the multicellular niche lead to MuSC dysfunction in aging (CODEX). We combine this knowledge with in vivo investigation of regenerative capacity and strength in aged mice. Finally, we perturb CD47 signaling in vivo using blocking antibodies to surmount the regenerative deficits in aged mice. The pro- posed analyses of newly identified aged MuSC subsets that can be prospectively isolated will provide fresh mechanistic insights into aging and inform therapeutic strategies to augment endogenous muscle repair.

项目概要根据美国最近的人口普查，老年人口将增加一倍多，达到 8000 万，到 2050 年，将有五分之一的美国人面临这一问题。衰老的特点是组织功能和再生能力下降肌肉减少症，也称为年龄依赖性骨骼肌质量和力量损失，是一种主要的公共疾病。影响 15% 老年人的健康问题，导致行动不便和生活质量下降。相关的肌肉损失与肌肉干细胞 (MuSC) 功能的损失并行，肌肉干细胞是肌肉的关键参与者。然而，与年龄相关的 MuSC 功能障碍的机制。获得 MuSC 衰老机制的两个主要障碍是 (1) 的异质性。 MuSC 群体老龄化，导致标准批量分析无效，以及 (2) 缺乏解决问题的工具这种异质性强调了单细胞研究的必要性。我们之前证明，衰老的 MuSC 是一个异质群体，由功能性的细胞组成。这一关键观察结果提出了一种促进肌肉再生的治疗策略。在这里，我们使用特定的细胞表面标记物来探索这种可能性。以及解决 MuSC 子集所需的一系列创新单细胞技术。将 CD47 视为细胞表面标记，其表达水平（而不是存在或不存在）区分功能 CD47lo 和功能失调的 CD47hi MuSC 亚群作为 SIRPα 的受体而广为人知，CD47 也是一种受体。我们发现 CD47hi MuSC 在衰老的肌肉中积聚并且异常前体。我们勇敢地承认，在衰老过程中，CD47hi MuSC 的积累会损害细胞的增殖。 CD47lo MuSC 通过分泌 THBS1，阻碍再生并导致肌肉减少症。具体目标是 (1) 确定 CD47 信号传导在衰老过程中如何出错，(2) 阐明转录后如何 CD47 的调节在衰老过程中发生改变，导致功能失调的 CD47hi MuSC 积累，并且 (3) 确定老化 MuSC 生态位中异常 THBS1 分泌对再生的影响。尖端单细胞技术，包括多维单细胞质谱流式技术（CyTOF）和多维单细胞质谱流式技术（CyTOF）复合组织成像（索引联合检测（CODEX））这些技术使我们能够同时跟踪 CD47lo 和 CD47hi MuSC (CyTOF) 中 40 多个不同的细胞和信号传导表型，并解决了空间如何多细胞生态位结构的变化导致衰老过程中 MuSC 功能障碍（CODEX）。最后，我们对老年小鼠的再生能力和强度进行了体内研究。使用阻断抗体进行体内 CD47 信号传导以克服老年小鼠的再生缺陷。对新发现的可前瞻性分离的老化 MuSC 子集进行的分析将提供新鲜的信息对衰老的机制见解并为增强内源性肌肉修复的治疗策略提供信息。