CD90 delineates distinct muscle stem cell states of quiescence and activation.

CD90 expression splits quiescent muscle stem cells in murine and human muscle into two subsets with distinct activation kinetics, with CD90+ cells exiting quiescence faster.

• Why it matters: Productive regeneration depends on how MuSCs switch from quiescence to activation, but the determinants of functional heterogeneity across states remain unclear.
• What they did: The study compared CD90+ve versus CD90-ve MuSC subsets in murine and human muscle, linking faster activation to an active CD90-AMPK axis and extracellular-matrix–maintained quiescence; it also tested Collagen VI binding to the Calcitonin receptor.
• The result: In healthy muscle, CD90+ve and CD90-ve MuSC numbers are similar, but CD90-ve MuSCs predominate in murine Duchenne and Ullrich congenital muscular dystrophy models, informing how repair stimulation may differ in dystrophic muscle.

AI summary of the abstract · may contain errors · not medical advice · read the paper.