Cells (Nov 2021)

Acid Sphingomyelinase Controls Early Phases of Skeletal Muscle Regeneration by Shaping the Macrophage Phenotype

  • Paulina Roux-Biejat,
  • Marco Coazzoli,
  • Pasquale Marrazzo,
  • Silvia Zecchini,
  • Ilaria Di Renzo,
  • Cecilia Prata,
  • Alessandra Napoli,
  • Claudia Moscheni,
  • Matteo Giovarelli,
  • Maria Cristina Barbalace,
  • Elisabetta Catalani,
  • Maria Teresa Bassi,
  • Clara De Palma,
  • Davide Cervia,
  • Marco Malaguti,
  • Silvana Hrelia,
  • Emilio Clementi,
  • Cristiana Perrotta

DOI
https://doi.org/10.3390/cells10113028
Journal volume & issue
Vol. 10, no. 11
p. 3028

Abstract

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Skeletal muscle regeneration is a complex process involving crosstalk between immune cells and myogenic precursor cells, i.e., satellite cells. In this scenario, macrophage recruitment in damaged muscles is a mandatory step for tissue repair since pro-inflammatory M1 macrophages promote the activation of satellite cells, stimulating their proliferation and then, after switching into anti-inflammatory M2 macrophages, they prompt satellite cells’ differentiation into myotubes and resolve inflammation. Here, we show that acid sphingomyelinase (ASMase), a key enzyme in sphingolipid metabolism, is activated after skeletal muscle injury induced in vivo by the injection of cardiotoxin. ASMase ablation shortens the early phases of skeletal muscle regeneration without affecting satellite cell behavior. Of interest, ASMase regulates the balance between M1 and M2 macrophages in the injured muscles so that the absence of the enzyme reduces inflammation. The analysis of macrophage populations indicates that these events depend on the altered polarization of M1 macrophages towards an M2 phenotype. Our results unravel a novel role of ASMase in regulating immune response during muscle regeneration/repair and suggest ASMase as a supplemental therapeutic target in conditions of redundant inflammation that impairs muscle recovery.

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