Endothelial cell signature in muscle stem cells validated by VEGFA-FLT1-AKT1 axis promoting survival of muscle stem cell

Abstract

Endothelial and skeletal muscle lineages arise from common embryonic progenitors. Despite their shared developmental origin, adult endothelial cells (ECs) and muscle stem cells (MuSCs) (satellite cells) have been thought to possess distinct gene signatures and signaling pathways. Here we shift this paradigm by uncovering how adult MuSC behavior is affected by the expression of a subset of EC transcripts. We used several computational analyses including single-cell RNAseq to show that MuSCs express low levels of canonical EC markers. We demonstrate that MuSC survival is regulated by one such prototypic endothelial signaling pathway (VEGFA-FLT1). Using pharmacological and genetic gain- and loss-of-function studies, we identify the FLT1-AKT1 axis as the key effector underlying VEGFA-mediated regulation of MuSC survival. All together, our data support that the VEGFA-FLT1-AKT1 pathway promotes MuSC survival during muscle regeneration, and highlights how the minor expression of select transcripts is sufficient for affecting cell behavior.

Spatial compartmentalization of signalling imparts source-specific functions on secreted factors

“…Recent studies have also described the role of VEGFA in supporting MP survival (Verma et al, 2021), thus we analysed the apoptosis in our systems and we noticed an increase in the number of MyoD + /Tunel + MP in MP VEGFAKO compared to WT animals (Figure S5D). This suggests that the .…”

“…Recent studies have also described the role of VEGFA in supporting MP survival (Verma et al, 2021), thus we analysed the apoptosis in our systems and we noticed an increase in the number of MyoD + /Tunel + MP in MP VEGFAKO compared to WT animals (Figure S5D). This suggests that the reduction of number of differentiating MP at 3 days after injury, might be due to either, or both, an impairment of proliferation and increase of apoptosis caused by VEGFA depletion specifically in MPs.…”

“…To assess whether ligands originating from different cell types are functionally equivalent, we again focused on VEGFA signaling, as it is vital for successful regeneration. Interestingly, beyond modulating angiogenesis, VEGFA has been proposed to have additional functions in healthy and diseased muscle (Verma et al, 2018(Verma et al, , 2021. In both undamaged and damaged muscles, the ligand Vegfa can be produced by FAPs, MPs, and ICs (Figure S3B and Table S2).…”

Long noncoding RNAlncMREFpromotes myogenic differentiation and muscle regeneration by interacting with the Smarca5/p300 complex

“…The single-cell sequencing data of basal condition and 3-day post CTX injury was from GEO database (GSE129057) ( 53 ) and raw counts were downloaded for further analysis. Bioinformatics analyses were performed in R (v. 4.0.2) and quality control was performed using the package Seurat (v. 4.0.2).…”

“…The Uniform manifold approximation and progression (UMAP) plot was used to visualize clustering data. Genes used to define different cell identities in the single-cell RNA sequencing were determined according to the published literature ( 53 ).…”