Mechanisms of recovery from mechanical injury of cultured rat
hepatocytes.
Sponsel, Heather T., Philip S. Guzelian, Susan E. S. Brown, Ruth
Breckon, Carla Ray, Francis R. Simon, and Robert J. Anderson.
Denver Veterans Affairs Medical Center and The Hepatobiliary
Center, University of Colorado Health Sciences Center, Denver,
Colorado
APStracts 3:0095C, 1996.
The mechanism(s) whereby hepatocytes restore denuded areas remains
unknown. We therefore studied the recovery of denuded areas made in
monolayers of primary cultures of rat hepatocytes. Minimal recovery
occurred in cells plated on plastic. Plating on matrigel produced
modest recovery (25% at 24 hours) while plating on a Type I collagen
substrate resulted in more than 70% recovery at 24 hours. The rate of
recovery on collagen could be attenuated by a monoclonal antibody
directed against the extracellular domain of the [beta]1 integrin
subunit. Monoclonal antibodies directed against CD44 (the hyaluron
receptor) and E-cadherin did not influence the rate of recovery.
Recovery could be stimulated, in dose-dependent fashion, by epidermal
and hepatocyte growth factors. The effects of epidermal and
hepatocyte growth factors to promote recovery occurred in the absence
of 5-bromo-2I-deoxyuridine uptake, suggesting a proliferation
-independent mechanism. Transforming growth factor [beta]1 inhibited
recovery. Exposure to selected cytokines (interleukins 1 and 2), an
adenine nucleotide (ATP_ S), adenosine, pertussis toxin and selected
agents which bind to fibronectin and other matrix component adhesive
sites (heparin and the RGD peptide) did not influence the rate of
recovery of hepatocytes. However, the peptide DGEA, which can bind to
collagen adhesive sites, attenuated recovery. These studies
demonstrate that primary cultures of rat hepatocytes require a
particular type of extracellular matrix to renew denuded areas and
that the [beta]1 integrin subunit may be involved in this recovery
process. Hepatocyte recovery of denuded areas can be modulated by
growth factors in both a stimulatory (epidermal and hepatocyte growth
factors) and an inhibitory (transforming growth factor [beta]1)
fashion.
Received 20 July 1995; accepted in final form 21 February 1996.
APS Manuscript Number C442-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 27 March 96