AJP - Cell Physiology, Vol 271, Issue 3 C721-C727, Copyright © 1996 by American Physiological Society
Mechanisms of recovery from mechanical injury of cultured rat hepatocytes
H. T. Sponsel, P. S. Guzelian, S. E. Brown, R. Breckon, C. Ray, F. R. Simon and R. J. Anderson
Denver Veterans Affairs Medical Center, Colorado, USA.
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
h), whereas plating on a type I collagen substrate resulted in > 70%
recovery at 24 h. 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 a 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-2'-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
[adenosine 5'-O-(3-thiotriphosphate)], adenosine, pertussis toxin, and
selected agents that 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.
