Human macrophages rescue myoblasts and myotubes from apoptosis through a set of adhesion molecular systems

J Cell Sci. 2006 Jun 15;119(Pt 12):2497-507. doi: 10.1242/jcs.02988. Epub 2006 May 23.

Abstract

The mechanisms underlying stromal cell supportive functions are incompletely understood but probably implicate a mixture of cytokines, matrix components and cell adhesion molecules. Skeletal muscle uses recruited macrophages to support post-injury regeneration. We and others have previously shown that macrophages secrete mitogenic factors for myogenic cells. Here, we focused on macrophage-elicited survival signals. We demonstrated that: (1) macrophage influx is temporally correlated with the disappearance of TUNEL-positive apoptotic myogenic cells during post-injury muscle regeneration in mice; (2) direct cell-cell contacts between human macrophages and myogenic cells rescue myogenic cells from apoptosis, as assessed by decreased annexin V labelling and caspase-3 activity, and by increased DIOC-6 staining, Bcl-2 expression and phosphorylation of Akt and ERK1/2 survival pathways; (3) four pro-survival cell-cell adhesion molecular systems detected by DNA macroarray are expressed by macrophages and myogenic cells in vitro and in vivo - VCAM-1-VLA-4, ICAM-1-LFA-1, PECAM-1-PECAM-1 and CX3CL1-CX3CR1; (4) macrophages deliver anti-apoptotic signals through all four adhesion systems, as assessed by functional analyses with blocking antibodies; and (5) macrophages more strongly rescue differentiated myotubes, which must achieve adhesion-induced stabilisation of their structure to survive. Macrophages could secure these cells until they establish final association with the matrix.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / physiology*
  • Cell Adhesion / physiology
  • Cell Adhesion Molecules / physiology*
  • Cell Membrane / physiology
  • Cell Survival / drug effects
  • Cell Survival / physiology
  • Cells, Cultured
  • Elapid Venoms / administration & dosage
  • Flow Cytometry
  • Humans
  • In Vitro Techniques
  • Macrophages / cytology
  • Macrophages / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Muscle Cells / cytology
  • Muscle Cells / physiology
  • Muscle Fibers, Skeletal / physiology*
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / injuries
  • Myoblasts / physiology*
  • Signal Transduction / physiology

Substances

  • Cell Adhesion Molecules
  • Elapid Venoms
  • notexin