Sphingolipids in Extracellular Vesicles Released From the Skeletal Muscle Plasma Membrane Control Muscle Stem Cell Fate During Muscle Regeneration

Affiliations

  • 1Laboratory of Cardiology, Metabolism, Nutrition and Diabetes (CarMeN), UMR INSERM 1060-INRAE 1397, University of Lyon, Pierre Benite, France.
  • 2Institut NeuroMyoGène, Laboratoire Physiopathologie et Génétique du Neurone et du Muscle, UMR INSERM 1315-CNRS 5261, University Claude Bernard Lyon 1, Lyon, France, Lyon, France.
  • 3Laboratoire Ecologie Microbienne, UMR CNRS 5557-INRAE 1418, VetAgroSup, Université of Lyon, Villeurbanne, France.
  • 4Université Paris Cité, INSERM, UMR S970, PARCC, Paris, France.
  • 5Unité de recherche CEED DIATHEC UR 7294 Université de Strasbourg, Strasbourg, France.
  • 6Oniris, INRAE, PAnTher, Nantes, France.
  • 7Centre d’Imagerie Quantitative Lyon-Est (CIQLE), Faculté de médecine Lyon-Est, Université of Lyon, Lyon, France.
  • 8Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA.
  • 9Institute for Biomedical Research and Innovation (IRIB) – National Research Council (CNR) of Italy, Palermo, Italy.
  • 10Diviomics Facility, US 58 BioSanD, University of Bourgogne, Dijon, France.

Abstract

Extracellular vesicles (EVs) represent a cytokine-independent pathway though which skeletal muscle (SkM) cells influence the fate of neighbouring cells, thereby regulating SkM metabolic homeostasis and regeneration. Although SkM-EVs are increasingly being explored as a therapeutic strategy to enhance muscle regeneration or to induce the myogenic differentiation of induced pluripotent stem cells (iPSCs), the mechanisms governing their release from muscle cells remain poorly described. Moreover, because muscle regeneration involves a tightly regulated inflammatory response it also important to determine how inflammation alters SkM-EV cargo and function in order to design more effective EV-based therapies. To address this knowledge gap, we isolated and characterized the large and small EVs (lEVs, sEVs) released from SkM cells under basal conditions and in response to TNF-α, a well-established inflammatory mediator elevated in both acute muscle injury and chronic inflammatory conditions such as type 2 diabetes. We then evaluated the regenerative roles of these EV subtypes in vivo using a mouse model of cardiotoxin-induced muscle injury, with a specific focus on their bioactive sphingolipid content. Using transmission, scanning or cryo-electron microscopy, lipidomic profiling and an adenoviral construct to express labelled CD63 in myotubes, we demonstrated that SkM cells release both sEVs and lEVs primarily from the plasma membrane. Notably, sEVs were generated from specialized membrane folds enriched in the EV markers ALIX (ALG-2 interacting protein X) and TSG101, as well as lipid raft-associated lipids. During regeneration, sEVs promoted M1 macrophage polarization and migration and muscle stem cell (MuSC) differentiation, thereby accelerating muscle repair. In contrast, lEVs inhibited and promoted MuSC proliferation and impaired the transition from the pro-inflammatory to the anti-inflammatory response, an essential step for promoting MuSC differentiation. Treatment of isolated muscle fibres with SkM-EVs revealed that the distinct effects of sEVs and lEVs on MuSC behaviour and macrophage phenotype could be largely explained by differences in their lipid composition, particularly the ratio of sphingosine-1-phosphate (S1P) subspecies. However, TNF-α exposure altered these ratios in sEVs and impaired their regenerative functions on MuSC and their effect on macrophage migration and polarization. These results demonstrate for the first time the importance of the sphingolipid content of EVs released by skeletal muscle in their regenerative function within muscle tissue, largely explained by their role as carriers of different subspecies of sphingosine-1-phosphate. This suggests that modulating the sphingolipid composition of EVs could be a viable strategy to enhance the regenerative potential of muscle tissue in addition to therapeutic interventions.

Keywords: extracellular vesicles; lipidomic; muscle stem cells; regeneration; skeletal muscle; sphingosine‐1‐phosphate.

News created on 14/09/2025

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