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FcgammaRIIB mediates C-reactive protein inhibition of endothelial NO synthase

Chieko Mineo1, Andrew K Gormley, Ivan S Yuhanna

  • 1Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.

Circulation Research
|November 5, 2005
PubMed

Insights

C-reactive protein (CRP) impairs endothelial nitric oxide synthase (eNOS) activation, promoting monocyte adhesion and endothelial dysfunction. This mechanism involves FcgammaRIIB and protein phosphatase 2A (PP2A).

Area of Science:

  • Cardiovascular Biology
  • Immunology
  • Cellular Signaling

Background:

  • C-reactive protein (CRP) is linked to cardiovascular disease risk and endothelial dysfunction.
  • The direct effects of CRP on the endothelium and their underlying mechanisms remain unclear.

Purpose of the Study:

  • To investigate the direct actions of CRP on endothelial cells.
  • To elucidate the molecular mechanisms by which CRP influences endothelial function.

Main Methods:

  • Experiments using cultured endothelial cells to assess eNOS activation and monocyte adhesion.
  • Investigating the role of protein phosphatase 2A (PP2A) and FcgammaRIIB receptor.
  • Utilizing FcgammaRIIB knockout mice to study in vivo effects.

Main Results:

  • CRP inhibits endothelial nitric oxide synthase (eNOS) activation by reducing phosphorylation at Ser1179.
  • CRP-induced eNOS inhibition is mediated by FcgammaRIIB and requires PP2A activity.
  • In vivo, CRP impairs acetylcholine-induced vascular responses in wild-type mice but not in FcgammaRIIB knockout mice.

Conclusions:

  • CRP directly impairs endothelial function by inhibiting eNOS activation through the FcgammaRIIB-PP2A pathway.
  • This provides a mechanistic link between CRP, FcgammaRIIB, and endothelial dysfunction.
  • Targeting this pathway may offer therapeutic strategies for cardiovascular diseases.

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