GSE171997
RNA-Sequencing of young and aged satellite cells before and after transplantation into the young niche
The function of skeletal muscle stem cells (MuSC) declines during aging, contributing to the advent of age-related myopathies. However, whether this decline is the result of accumulating cellular damage, altered heterogeneity in stem cell populations or due to the effect of the changing niche environment remains largely unknown. By scRNA-Seq, we show that the age-related reduction in the MuSC pool is not stochastic, with different subpopulations being distinctly affected in aging. Using an in vivo allogeneic stem cell transplantation model, we show that exposure of MuSCs from old mice to a youthful niche environment significantly restores the gene expression of genes that are altered in aging. We show that age-related changes in the MuSC transcriptome are mainly driven by alterations in chromatin and transcription but are not due to posttranscriptional mechanisms affecting RNA stability. Furthermore, our data indicates that the portion of the genome that is activated in aging is significantly more responsive to restoration by niche factors compared to the repressed counterpart. Taken together, our data reveals that the niche environment plays a decisive role in controlling the transcriptional activity of MuSCs. Overall design: Satellite cells were isolated by Fluorescence-Activated Cell Sorting (FACS) from either young or aged Pax7-eGFP mice. 10 000-20 000 of these freshly-sorted cells were subsequently injected into the TA muscle of young NCG (NOD-Prkdcem26Cd52Il2rgem26Cd22/NjuCrl) immunocompromised mice that had their hindlimb irradiated 24 hours prior to injection. 21 days post-engraftment, donor satellite cells were re-isolated by FACS. RNA-Seq libraries were created from young or aged cells at T0 (before transplantation) and at T21 (after transplantation into young NCG mice) using SMART-Seq HT for conversion into cDNA followed by Nextera XT for the addition of Illumina sequencing adapters.