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Role of satellite cells in microvascular recovery during skeletal muscle regeneration

卫星细胞在骨骼肌再生过程中微血管恢复中的作用

基本信息

批准号：
10415837
负责人：
Nicole Lynne Jacobsen
金额：
$ 7.17万
依托单位：
UNIVERSITY OF MISSOURI-COLUMBIA
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-05-01 至 2023-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10415837
关键词：
Acute Address Adult Affect Aging Apoptosis Attenuated Basement membrane Blood Vessels Blood capillaries Cell Cycle Progression Cell Proliferation Cell Survival Cells Conditioned Culture Media Confocal Microscopy Cues Data Degenerative Disorder Development Diffusion Diphtheria Toxin Disease Endothelial Cells Endothelium Event Female Flow Cytometry Fluorescence-Activated Cell Sorting Growth Homeostasis Impairment In Vitro Inflammatory Inflammatory Response Injections Injury Intercellular Junctions Ischemia KDR gene Knowledge Link Mediating Metabolic Microcirculation Microvascular Permeability Molecular Mus Muscle Muscle satellite cell Muscular Dystrophies Natural regeneration Nature Nutrient Oxygen Paracrine Communication Pathway interactions Perfusion Pericytes Permeability Phenotype Process Recovery Recovery of Function Regulation Research Project Grants Role Signal Transduction Site Skeletal Muscle Skeletal muscle injury Structure Supporting Cell Testing Time Tissues Transgenic Mice Trauma Trauma recovery Vascular Endothelial Growth Factors Vascular remodeling Wild Type Mouse angiogenesis barium chloride base cadherin 5 cell motility confocal imaging density experimental study improved in vivo inducible gene expression injured insight macromolecule male muscle regeneration myogenesis novel novel therapeutics protein expression recruit regeneration function repaired response restoration satellite cell stem cells

项目摘要

Project Summary Skeletal muscle has the remarkable ability to repair itself following injury through activation, proliferation, and differentiation of resident stem cells (satellite cells, SCs). Acute injury destroys capillary networks and abolishes perfusion coincident with myofiber degeneration. Although the cellular and molecular events of myofiber regeneration are well defined, little is known of corresponding events in the regenerating microvasculature. To address this gap in knowledge, local injection of the myotoxin BaCl2 is used to initiate degeneration and regeneration in the gluteus maximus muscle (GM) of adult (~4 mo) male and female mice. Surviving endothelial cell (EC) segments sprout within 2-3 days post injury (d PI) then elongate and fuse into new capillary networks that become perfused by 5d PI, which coincides with the initial stages of myofiber regeneration. Despite their intimate association and concurrent activation, crosstalk between myogenesis and microvascular regeneration is poorly understood. The central hypothesis of this project is that paracrine signaling from SC progeny is integral to the regeneration and stabilization of microvascular networks. Transgenic mice in which SCs have been depleted prior to injury, and therefore cannot regenerate myofibers, will be used. Preliminary data show that microvascular density is reduced following injury in the absence of myogenesis when compared to wild-type mice. Thus, confocal microscopy and flow cytometry will be used to determine whether myogenesis controls endothelial tip cell selection, proliferation, and/or survival as the basis for this attenuated angiogenic response after injury (Aim 1). Confocal imaging and immunostaining of whole mount GM for tip cell markers (e.g., VEGFR2) will assess the magnitude of EC sprouting; proliferation of ECs will be analyzed in vivo with EdU. In addition, primary ECs will be isolated from injured GM to determine the extent of endothelial cell cycle progression and apoptosis-mediated vascular pruning using fluorescence activated cell sorting. In Aim 2, the role of myogenesis in the regulation of the endothelial permeability barrier will be tested because the diffusional exchange of oxygen, nutrients, and metabolic byproducts between myofibers and their microvascular supply is integral in restoring and maintaining tissue homeostasis. Because barrier integrity recovers early in regeneration in wild-type mice but remains leaky in the absence of myogenesis, pericyte (PC) integration into the nascent microvascular wall and organization of VE-cadherin based intercellular junctions will be evaluated by immunostaining in whole GM; both components are essential for tight EC-EC junctions. Experiments using conditioned medium from myogenic cells will investigate the direct and indirect regulation of intercellular junctions through paracrine signaling in vitro. Results from these studies will provide critical new insight into how myogenesis affects both the initial microvascular regeneration and long-term stabilization of networks after muscle injury. This project represents a critical step towards developing novel therapies to promote muscle recovery from trauma, ischemia, and disease.

项目总结