Inhibition of inflammatory CCR2 signaling promotes aged muscle regeneration and strength recovery after injury

Nat Commun. 2020 Aug 20;11(1):4167. doi: 10.1038/s41467-020-17620-8.

Abstract

Muscle regeneration depends on a robust albeit transient inflammatory response. Persistent inflammation is a feature of age-related regenerative deficits, yet the underlying mechanisms are poorly understood. Here, we find inflammatory-related CC-chemokine-receptor 2 (Ccr2) expression in non-hematopoietic myogenic progenitors (MPs) during regeneration. After injury, the expression of Ccr2 in MPs corresponds to the levels of its ligands, the chemokines Ccl2, 7, and 8. We find stimulation of Ccr2-activity inhibits MP fusion and contribution to myofibers. This occurs in association with increases in MAPKp38δ/γ signaling, MyoD phosphorylation, and repression of the terminal myogenic commitment factor Myogenin. High levels of Ccr2-chemokines are a feature of regenerating aged muscle. Correspondingly, deletion of Ccr2 in MPs is necessary for proper fusion into regenerating aged muscle. Finally, opportune Ccr2 inhibition after injury enhances aged regeneration and functional recovery. These results demonstrate that inflammatory-induced activation of Ccr2 signaling in myogenic cells contributes to aged muscle regenerative decline.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Animals
  • Cell Transplantation / methods
  • Chemokine CCL2 / metabolism
  • Chemokine CCL7 / metabolism
  • Chemokine CCL8 / metabolism
  • Inflammation Mediators / metabolism*
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Muscle Development / genetics
  • Muscle, Skeletal / injuries
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / physiopathology*
  • Myogenin / genetics
  • Myogenin / metabolism
  • Receptors, CCR2 / genetics
  • Receptors, CCR2 / metabolism*
  • Regeneration / genetics
  • Regeneration / physiology*
  • Satellite Cells, Skeletal Muscle / cytology
  • Satellite Cells, Skeletal Muscle / metabolism
  • Satellite Cells, Skeletal Muscle / transplantation
  • Signal Transduction / genetics
  • Signal Transduction / physiology*
  • Wounds and Injuries / genetics
  • Wounds and Injuries / physiopathology
  • Wounds and Injuries / therapy

Substances

  • Chemokine CCL2
  • Chemokine CCL7
  • Chemokine CCL8
  • Inflammation Mediators
  • Myogenin
  • Receptors, CCR2