Cytokines regulate apolipoprotein b secretion by caco-2 cells:
differential effects of il-6 and tgf-b1.
Murthy, Shubha, Satya N. Mathur, Gary Varilekd, Warren Bishop, F.
Jeffrey Field.
University of Iowa, Departments of Internal Medicine and Pediatrics
and the Veterans Administration, Iowa City, IA 52242
APStracts 2:0122G, 1995.
A variety of cytokines are found in the intestinal mucosa of
individuals with inflammatory diseases. The potential role of
cytokines in mediating lipoprotein assembly and secretion in the
human intestinal cell line, CaCo-2, was investigated. IL-1[beta], IL
-6 and TNF-[alpha] decreased the basolateral secretion of apo B with
IL-6 being the most potent. IL-6 was also found to inhibit
triacylglycerol secretion. In contrast, TGF- [beta]1 increased the
secretion of apo B and triacylglycerol. In pulse-chase experiments,
IL-6 decreased the rate of synthesis and secretion of apo B100 and
B48 without altering the rate of apo B degradation, whereas TGF-b1
increased the rate of synthesis and secretion of apo B100 and B48.
Degradation of apo B was also not affected by TGF- [beta]1. The
abundance of apo B mRNA in cells incubated with IL-6 was decreased
whereas cells incubated with TGF-b1 had higher levels of apo B mRNA.
Received 15 August 1994; accepted in final form 24 June 1995.
APS Manuscript Number G304-4.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 6 July 1995.