Morphological relationships of von Willebrand factor, type VI collagen, and fibrillin in human vascular subendothelium. Academic Article uri icon

Overview

abstract

  • von Willebrand factor (vWF) plays an important role in the process of platelet adhesion after endothelial injury by serving as a bridge between constituents of the vascular subendothelium and platelet membrane receptors. We previously presented evidence that type VI collagen microfibrils serve as a binding site for vWF in human vascular subendothelium. However, others have proposed that vWF is not associated with type VI collagen but rather with the thicker elastin-associated microfibrils, which contain several proteins including fibrillin. We therefore investigated the relationships among vWF, type VI collagen, and fibrillin in human vascular subendothelium by immunoelectron microscopy using single- and double-labeling immunogold localization techniques. In addition, we observed the three-dimensional ultrastructure of vWF-microfibril complexes by stereo paired micrographs and stereo viewer. We found that vWF co-localizes only with the type VI collagen microfibrils in subendothelium but not with fibrillin microfibrils or striated collagen. The vWF is present in subendothelium in the form of electron-dense aggregates having diameters varying between 65 and 80 nm that are closely associated with, and enmesh, the type VI collagen microfibrils and have structural similarities to intracellular Weibel-Palade bodies. The occasional co-localization of type VI collagen and fibrillin adjacent to internal elastic lamina was observed. These results are consistent with the hypothesis that type VI collagen, but not fibrillin-containing microfibrils, serves as a physiologically relevant binding site for vWF in the vascular subendothelium, where the type VI collagen-vWF complex may play an important role modulating the hemostatic response to vascular injury.

publication date

  • July 1, 1996

Research

keywords

  • Collagen
  • Endothelium, Vascular
  • Extracellular Matrix Proteins
  • Microfilament Proteins
  • von Willebrand Factor

Identity

PubMed Central ID

  • PMC1865249

Scopus Document Identifier

  • 0029999602

PubMed ID

  • 8686752

Additional Document Info

volume

  • 149

issue

  • 1