Carbon monoxide and nitric oxide mediate cytoskeletal reorganization in microvascular cells via vasodilator-stimulated phosphoprotein phosphorylation: evidence for blunted responsiveness in diabetes

Diabetes. 2008 Sep;57(9):2488-94. doi: 10.2337/db08-0381. Epub 2008 Jun 16.

Abstract

Objective: We examined the effect of the vasoactive agents carbon monoxide (CO) and nitric oxide (NO) : n the phosphorylation and intracellular redistribution of vasodilator-stimulated phosphoprotein (VASP), a critical actin motor protein required for cell migration that also controls vasodilation and platelet aggregation.

Research design and methods: We examined the effect of donor-released CO and NO in endothelial progenitor cells (EPCs) and platelets from nondiabetic and diabetic subjects and in human microvascular endothelial cells (HMECs) cultured under low (5.5 mmol/l) or high (25 mmol/l) glucose conditions. VASP phosphorylation was evaluated using phosphorylation site-specific antibodies.

Results: In control platelets, CO selectively promotes phosphorylation at VASP Ser-157, whereas NO promotes phosphorylation primarily at Ser-157 and also at Ser-239, with maximal responses at 1 min with both agents on Ser-157 and at 15 min on Ser-239 with NO treatment. In diabetic platelets, neither agent resulted in VASP phosphorylation. In nondiabetic EPCs, NO and CO increased phosphorylation at Ser-239 and Ser-157, respectively, but this response was markedly reduced in diabetic EPCs. In endothelial cells cultured under low glucose conditions, both CO and NO induced phosphorylation at Ser-157 and Ser-239; however, this response was completely lost when cells were cultured under high glucose conditions. In control EPCs and in HMECs exposed to low glucose, VASP was redistributed to filopodia-like structures following CO or NO exposure; however, redistribution was dramatically attenuated under high glucose conditions.

Conclusions: Vasoactive gases CO and NO promote cytoskeletal changes through site- and cell type-specific VASP phosphorylation, and in diabetes, blunted responses to these agents may lead to reduced vascular repair and tissue perfusion.

Publication types

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

MeSH terms

  • Blood Platelets / cytology
  • Blood Platelets / metabolism
  • Carbon Monoxide / metabolism*
  • Carbon Monoxide / pharmacology
  • Cell Adhesion Molecules / metabolism*
  • Cell Movement / drug effects
  • Cell Movement / physiology
  • Cells, Cultured
  • Cytoskeleton / drug effects
  • Cytoskeleton / metabolism*
  • Diabetic Angiopathies / metabolism*
  • Diabetic Angiopathies / pathology
  • Endothelial Cells / cytology
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism*
  • Flow Cytometry
  • Humans
  • Microcirculation / cytology
  • Microcirculation / metabolism
  • Microfilament Proteins / metabolism*
  • Nitric Oxide / metabolism*
  • Nitric Oxide / pharmacology
  • Phosphoproteins / metabolism*
  • Phosphorylation / drug effects

Substances

  • Cell Adhesion Molecules
  • Microfilament Proteins
  • Phosphoproteins
  • vasodilator-stimulated phosphoprotein
  • Nitric Oxide
  • Carbon Monoxide