Murthy S, Mathur S N, Varilek G, Bishop W, Field F J
Department of Internal Medicine, University of Iowa, Iowa City, USA.
Am J Physiol. 1996 Jan;270(1 Pt 1):G94-102. doi: 10.1152/ajpgi.1996.270.1.G94.
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.
在患有炎症性疾病的个体的肠道黏膜中发现了多种细胞因子。研究了细胞因子在介导人肠道细胞系Caco-2中脂蛋白组装和分泌方面的潜在作用。白细胞介素-1β、白细胞介素-6（IL-6）和肿瘤坏死因子-α均降低了载脂蛋白B（apo B）的基底外侧分泌，其中IL-6作用最为显著。还发现IL-6抑制三酰甘油分泌。相比之下，转化生长因子-β1（TGF-β1）增加了apo B和三酰甘油的分泌。在脉冲追踪实验中，IL-6降低了apo B-100和apo B-48的合成和分泌速率，而未改变apo B的降解速率，而TGF-β1增加了apo B-100和apo B-48的合成和分泌速率。TGF-β1也不影响apo B的降解。与IL-6孵育的细胞中apo B mRNA丰度降低，而与TGF-β1孵育的细胞中apo B mRNA水平较高。在小肠炎症的情况下，细胞因子可能导致观察到的小肠对脂肪和其他营养物质的吸收不良。
