title: Versican and CD44 in in vitro valvular interstitial cell injury and repair.
abstract: BACKGROUND
  Versican is one of the key components of the extracellular matrix (ECM) that is expressed during injury, inflammatory, and repair processes. The current study evaluated the relationship between versican and the membrane receptor CD44 during in vitro valvular interstitial cell (VIC) injury and repair.
  
  
  METHODS
  Subconfluent, confluent, and wounded cultures of human VICs were fixed and immunostained to detect versican and the membrane receptor CD44. To examine the relationship between versican and CD44, a blocking antibody to CD44 was added to cultured VICs, and in vitro wound repair along with pericellular versican organization and stress fiber formation were examined.
  
  
  RESULTS
  Immunohistochemistry demonstrated that versican is prominent intracellularly, as well as extracellularly, in actively proliferating VICs. In contrast, versican was only localized to fibrils in the extracellular space in between cells in confluent (quiescent) cultures. Following wounding, versican expression was up-regulated, and it was secreted as ECM at the trailing edge of migrating cells. The staining for CD44 was similarly localized to the trailing edge of migrating VICs in wounded cultures. Treatment of VICs with a CD44-blocking antibody disrupted the organization of versican in the pericellular matrix and inhibited stress fiber formation in these cells. Functionally, blocking CD44 significantly inhibited VIC-mediated contraction of type I collagen gels (35.7%±0.7% vs. 23.3%±1.4% of initial gel area, P<.01).
  
  
  CONCLUSIONS
  Versican is a key component of the provisional wound repair ECM that is expressed following injury to VICs. The receptor CD44 plays an important role in organizing the provisional ECM.
  
  
  CONCLUSIONS
  Our data suggests VICs synthesize and secrete versican following injury. These cells also up-regulate CD44, a receptor that binds versican. Blocking CD44 disrupted the organization of versican and inhibited stress fiber formation. Functionally, blocking CD44 inhibited cell-mediated contraction of a collagen matrix. Collectively, these data suggest versican expression and organization are important to valve cell injury and repair.
authors.affiliation: UBC James Hogg Research Centre, Institute for Heart + Lung Health, Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Jon M
authors.initials: JM
authors.lastname: Carthy
authors.forename: Seti
authors.initials: S
authors.lastname: Boroomand
authors.forename: Bruce M
authors.initials: BM
authors.lastname: McManus
mesh_terms: D000368:Aged; D057134:Antibodies, Neutralizing / Q000494:pharmacology; D001021:Aortic Valve / Q000293:injuries / Q000378:metabolism / Q000473:pathology*; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D018960:Hyaluronan Receptors / Q000276:immunology / Q000378:metabolism*; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008297:Male; D018613:Microscopy, Confocal; D022502:Stress Fibers / Q000187:drug effects / Q000378:metabolism; D053675:Versicans / Q000378:metabolism*; D014945:Wound Healing / Q000502:physiology*
chemical_list: D057134:Antibodies, Neutralizing; C497483:CD44 protein, human; D024042:Collagen Type I; D018960:Hyaluronan Receptors; D053675:Versicans