AJP - Cell Physiology, Vol 259, Issue 4 C577-C585, Copyright © 1990 by American Physiological Society
A factor in serum lowers resistance and opens tight junctions of MDCK cells
G. Conyers, L. Milks, M. Conklyn, H. Showell and E. Cramer
Department of Anatomy and Cell Biology, State University of New York, Brooklyn 11203.
During an inflammatory reaction, factors in blood affect the permeability
of endothelium and possibly organ epithelium. In this study we partially
characterized a factor in human and canine blood that lowered the
transepithelial electrical resistance (TER) of canine kidney epithelial
cells (MDCK) and examined whether vascular permeability factors [complement
component C3a and C5a and platelet-activating factor (PAF)] were
responsible for this reaction. C3a and C5a caused a small (10-13%)
dose-related decrease in the TER (alpha = 0.05), whereas PAF had no effect.
In contrast, the factor found in both serum and plasma caused a large
(60-83%) dose-dependent decrease (saturated at 30%) in the TER that was
reversible within 60 min. The blood factor, which does not appear to be
albumin, was heat stable and has an apparent molecular mass of 67 kDa. It
preferentially decreased the TER of the epithelium when it came in contact
with its basolateral surface and significantly lowered the resistance
within 60 min by opening the zonula occludentes. These findings suggest
that C3a, C5a, and a factor in blood can directly modulate the permeability
of renal epithelium.
