AJP - Gastrointestinal and Liver Physiology, Vol 270, Issue 1 94-102, Copyright © 1996 by American Physiological Society

ARTICLES

Cytokines regulate apolipoprotein B secretion by Caco-2 cells: differential effects of IL-6 and TGF-beta 1

S. Murthy, S. N. Mathur, G. Varilek, W. Bishop and F. J. Field
Department of Internal Medicine, University of Iowa, Iowa City, USA.

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. Interleukin-1 beta, interleukin-6 (IL-6), and tumor necrosis factor-alpha all decreased the basolateral secretion of apolipoprotein B (apo B), with IL-6 being the most potent. IL-6 was also found to inhibit triacylglycerol secretion. In contrast, transforming growth factor-beta 1 (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 B-100 and apo B-48 without altering the rate of apo B degradation, whereas TGF-beta 1 increased the rate of synthesis and secretion of apo B-100 and apo B-48. 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-beta 1 had higher levels of apo B mRNA. In conditions of small intestinal inflammation, cytokines could contribute to the observed malabsorption of fat and other nutrients by the small intestine.

This article has been cited by other articles:

				K. Singh, O. A. Batuman, H. O. Akman, M. H. Kedees, V. Vakil, and M. M. Hussain Differential, Tissue-specific, Transcriptional Regulation of Apolipoprotein B Secretion by Transforming Growth Factor beta J. Biol. Chem., October 11, 2002; 277(42): 39515 - 39524. [Abstract] [Full Text] [PDF]

				S. Murthy, E. Born, S. N. Mathur, and F. J. Field LXR/RXR activation enhances basolateral efflux of cholesterol in CaCo-2 cells J. Lipid Res., July 1, 2002; 43(7): 1054 - 1064. [Abstract] [Full Text] [PDF]

				S. Murthy, S. N. Mathur, and F. J. Field Tumor Necrosis Factor-alpha and Interleukin-1beta Inhibit Apolipoprotein B Secretion in CaCo-2 Cells via the Epidermal Growth Factor Receptor Signaling Pathway J. Biol. Chem., March 24, 2000; 275(13): 9222 - 9229. [Abstract] [Full Text] [PDF]

				E. Levy, Y. Rizwan, L. Thibault, G. Lepage, S. Brunet, L. Bouthillier, and E. Seidman Altered lipid profile, lipoprotein composition, and oxidant and antioxidant status in pediatric Crohn disease Am. J. Clinical Nutrition, March 1, 2000; 71(3): 807 - 815. [Abstract] [Full Text] [PDF]

				C. Darimont, N. Gradoux, and A. de Pover Epidermal growth factor regulates fatty acid uptake and metabolism in Caco-2 cells Am J Physiol Gastrointest Liver Physiol, March 1, 1999; 276(3): G606 - G612. [Abstract] [Full Text] [PDF]

				S. Murthy, E. Born, S. Mathur, and F. J. Field 13-Hydroxy octadecadienoic acid (13-HODE) inhibits triacylglycerol-rich lipoprotein secretion by CaCo-2 cells J. Lipid Res., June 1, 1998; 39(6): 1254 - 1262. [Abstract] [Full Text]