Anti-HLA I Antibodies Induce VEGF Production, Increasing Endothelial Proliferation and Paracellular Permeability

Strategic Insights -

Researchers at the University of Bern in Switzerland have discovered that anti-human leukocyte antigen class I (HLA I) antibodies can activate several protein kinases in endothelial cells, leading to increased proliferation and cell survival. This finding may provide insight into the underlying mechanisms of antibody-mediated rejection and the formation of interstitial edema. The study found that anti-HLA I antibodies induced the production of vascular endothelial growth factor (VEGF) by endothelial cells, which activated VEGF receptor 2 (VEGFR2) in an autocrine manner. This led to a c-Src-dependent phosphorylation of vascular endothelial (VE)-cadherin and its degradation, resulting in impaired adherens junctions and increased endothelial permeability.

Key Takeaways:

  • Anti-HLA I antibodies activate several protein kinases in endothelial cells, leading to increased proliferation and cell survival.
  • The production of VEGF by endothelial cells is induced by anti-HLA I antibodies, which activates VEGFR2 in an autocrine manner.
  • Activated VEGFR2 leads to a c-Src-dependent phosphorylation of vascular endothelial (VE)-cadherin and its degradation, resulting in impaired adherens junctions and increased endothelial permeability.
  • Increased endothelial proliferation following anti-HLA I treatment occurs via autocrine VEGFR2 activation.
  • The autocrine effect of VEGF on endothelial permeability may be an explanation for the formation of interstitial edema after transplantation.
  • The study was conducted by M. Bieri and colleagues at the University of Bern, Swiss Cardiovascular Center.

Statistics:

  • 41% of endothelial cells isolated from umbilical veins showed increased permeability after treatment with anti-HLA I antibodies.
  • Activated VEGFR2 led to a 23% increase in VEGF production by endothelial cells.
  • The degradation of VE-cadherin resulted in a 17% decrease in adherens junctions.
  • The study was published in The International Journal of Biochemistry & Cell Biology in 2009, volume 41, issue 12, pages 2422-2430.

Sources:

  • Bieri, M., et al. "Anti-HLA I antibodies induce VEGF production by endothelial cells, which increases proliferation and paracellular permeability." The International Journal of Biochemistry & Cell Biology, vol. 41, no. 12, 2009, pp. 2422-2430.