Identification of VLDLR as a novel endothelial cell receptor for fibrin that modulates fibrin-dependent transendothelial migration of leukocytes

Blood. 2012 Jan 12;119(2):637-44. doi: 10.1182/blood-2011-09-382580. Epub 2011 Nov 17.

Abstract

While testing the effect of the (β15-66)(2) fragment, which mimics a pair of fibrin βN-domains, on the morphology of endothelial cells, we found that this fragment induces redistribution of vascular endothelial-cadherin in a process that is inhibited by the receptor-associated protein (RAP). Based on this finding, we hypothesized that fibrin may interact with members of RAP-dependent low-density lipoprotein (LDL) receptor family. To test this hypothesis, we examined the interaction of (β15-66)(2), fibrin, and several fibrin-derived fragments with 2 members of this family by ELISA and surface plasmon resonance. The experiments showed that very LDL (VLDL) receptor (VLDLR) interacts with high affinity with fibrin through its βN-domains, and this interaction is inhibited by RAP and (β15-66)(2). Furthermore, RAP inhibited transendothelial migration of neutrophils induced by fibrin-derived NDSK-II fragment containing βN-domains, suggesting the involvement of VLDLR in fibrin-dependent leukocyte transmigration. Our experiments with VLDLR-deficient mice confirmed this suggestion by showing that, in contrast to wild-type mice, fibrin-dependent leukocyte transmigration does not occur in such mice. Altogether, the present study identified VLDLR as a novel endothelial cell receptor for fibrin that promotes fibrin-dependent leukocyte transmigration and thereby inflammation. Establishing the molecular mechanism underlying this interaction may result in the development of novel inhibitors of fibrin-dependent inflammation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antigens, CD / metabolism
  • Cadherins / metabolism
  • Cells, Cultured
  • Endothelium, Vascular / metabolism*
  • Enzyme-Linked Immunosorbent Assay
  • Fibrin / metabolism*
  • Fibrin Fibrinogen Degradation Products / metabolism*
  • Fluorescent Antibody Technique
  • Humans
  • LDL-Receptor Related Protein-Associated Protein / metabolism*
  • Leukocytes / cytology*
  • Leukocytes / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Peritonitis / etiology
  • Peritonitis / metabolism
  • Peritonitis / pathology
  • Receptors, LDL / physiology*
  • Surface Plasmon Resonance
  • Transendothelial and Transepithelial Migration / physiology*

Substances

  • Antigens, CD
  • Cadherins
  • Fibrin Fibrinogen Degradation Products
  • LDL-Receptor Related Protein-Associated Protein
  • NDSK-II
  • Receptors, LDL
  • VLDL receptor
  • cadherin 5
  • Fibrin