GSE169411
Transcriptome Profiling of Distinct Stromal Cell Populations in Skeletal Muscle Following Acute Injury
Skeletal muscle regeneration is primarily accomplished through the concerted action of the myoblasts as well as the supporting stromal cells. Following accomplishment of injury repair, activated stromal cells disappear via apoptosis. In the case of muscle dystrophies where in a chronic inflammatory environment is present, activated stromal cells are transformed into a myofibroblastic state with the deposition of extracellular matrix components. Excessive accumulation of ECM leads to irreversible fibrosis and tissue deterioration. A distinct stromal cell population named fibro-adipogenic precursors (FAPs) are known to be responsible for contribution to fibrosis and fatty infiltration. Fibrosis is also evident in disuse atrophy and sarcopenia without any significant inflammation. This study aims to analyze the heterogeneous population of FAPs comparatively in the course of acute damage and immobilization models.   We isolated and analyzed the mononuclear cell population of skeletal muscles following tenotomy and denervation models in mice. Immunophenotyping of the FAPs was conducted based on exclusion of CD45, CD31 and CD11b and a comparative analysis was accomplished on three different subpopulations of i) CD140a(+), Sca1(+) ii) CD140a(+), Sca1(-) iii) CD140a(-), Sca1(+). High-throughput transcriptome analysis was employed to further characterize the transcriptome of these three cell populations and compare their quiescent and activated states.  Results: Investigated sub-populations exhibited diverse activation properties and kinetics for each studied model. While CD140a(+), Sca1(+) was the predominating activated population along with tenotomy, denervation majorly stimulated the proliferation of CD140a(+), Sca1(+) cells. Both immobilization models lacked myofiber damage and exhibited a minute inflammatory response compared to the acute damage. Transcriptome analysis supports commonalities in upregulation of ECM components in diverse subpopulation of cells as well as discriminating candidate cell surface markers.  Skeletal muscle regeneration is primarily accomplished through the concerted action of the myoblasts as well as the supporting stromal cells. Following accomplishment of injury repair, activated stromal cells disappear via apoptosis. In the case of muscle dystrophies where in a chronic inflammatory environment is present, activated stromal cells are transformed into a myofibroblastic state with the deposition of extracellular matrix components. Excessive accumulation of ECM leads to irreversible fibrosis and tissue deterioration. A distinct stromal cell population named fibro-adipogenic precursors (FAPs) are known to be responsible for contribution to fibrosis and fatty infiltration. Fibrosis is also evident in disuse atrophy and sarcopenia without any significant inflammation. This study aims to analyze the heterogeneous population of FAPs comparatively in the course of acute damage and immobilization models.   We isolated and analyzed the mononuclear cell population of skeletal muscles following tenotomy and denervation models in mice. Immunophenotyping of the FAPs was conducted based on exclusion of CD45, CD31 and CD11b and a comparative analysis was accomplished on three different subpopulations of i) CD140a(+), Sca1(+) ii) CD140a(+), Sca1(-) iii) CD140a(-), Sca1(+). High-throughput transcriptome analysis was employed to further characterize the transcriptome of these three cell populations and compare their quiescent and activated states.  Results: Investigated sub-populations exhibited diverse activation properties and kinetics for each studied model. While CD140a(+), Sca1(+) was the predominating activated population along with tenotomy, denervation majorly stimulated the proliferation of CD140a(+), Sca1(+) cells. Both immobilization models lacked myofiber damage and exhibited a minute inflammatory response compared to the acute damage. Transcriptome analysis supports commonalities in upregulation of ECM components in diverse subpopulation of cells as well as discriminating candidate cell surface markers. Overall design: RNASeq was performed on freshly isolated stromal cell populations of the control and injured (three days) skeletal muscle based on three different immunophenotypes.