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Murine Aortic Crush Injury: An Efficient In Vivo Model of Smooth Muscle Cell Proliferation and Endothelial Function
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MFG-E8 activates proliferation of vascular smooth muscle cells via integrin signaling

Mingyi Wang1, Zongming Fu, James Wu

  • 1Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging-National Institutes of Health, Baltimore, MD 21224, USA. mingyiw@grc.nia.nih.gov

Aging Cell
|March 6, 2012
PubMed

Insights

Milk fat globule EGF-8 protein (MFG-E8) accumulation drives vascular smooth muscle cell (VSMC) proliferation in aging arteries. This occurs via integrin/ERK1/2 signaling, contributing to age-related arterial changes.

Area of Science:

  • Vascular biology
  • Cellular and molecular medicine
  • Aging research

Background:

  • Milk fat globule EGF-8 protein (MFG-E8) accumulates in arterial walls during aging and disease.
  • MFG-E8 is known to induce VSMC invasion, but its effect on VSMC proliferation, a key aspect of arterial inflammation, is not understood.

Purpose of the Study:

  • To investigate the role of MFG-E8 in VSMC proliferation in the context of arterial aging.
  • To elucidate the molecular mechanisms by which MFG-E8 influences VSMC proliferation.

Main Methods:

  • Assessed cell cycle markers (PCNA, Ki67) in rat aortae of different ages.
  • Isolated and cultured VSMCs from young and old rats.
  • Examined the effects of exogenous and endogenous MFG-E8 on VSMC proliferation in vitro.
  • Utilized techniques including Western blotting, immunofluorescence, and cell cycle analysis.
  • Investigated the involvement of integrin αvβ5 and ERK1/2 signaling pathways.

Main Results:

  • VSMC proliferation markers and cell cycle progression accelerate with age in rat aortae.
  • Aging is associated with increased MFG-E8 and integrin αvβ5 coexpression and interaction.
  • Exogenous or endogenous MFG-E8 promotes VSMC proliferation via integrin αvβ5 and ERK1/2 signaling.
  • MFG-E8 upregulates cell cycle proteins (PCNA, CDK4) and accelerates cell cycle phases.
  • MFG-E8 silencing or pathway inhibition reduces VSMC proliferation.

Conclusions:

  • MFG-E8 signaling is a key mechanism driving the age-associated increase in aortic VSMC proliferation.
  • MFG-E8 dose-dependently regulates cell cycle molecules and facilitates VSMC proliferation through the integrin/ERK1/2 pathway.
  • Targeting MFG-E8 signaling may offer therapeutic potential for age-related vascular diseases.

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