Conjugated Linoleic Acid Alters Global Gene Expression in Human Intestinal-Like Caco-2 Cells in an Isomer-Specific Manner3

Abstract

Conjugated linoleic acid (CLA) exhibits isomer-specific effects on transepithelial calcium (Ca) transport as well as on cell growth in human intestinal-like Caco-2 cells. However, the molecular mechanisms of action are still unclear. Therefore, this study used a transcriptomic approach to help elucidate the molecular mechanisms underlying such isomer-specific effects. Caco-2 cells were treated with 80 micromol/L linoleic acid (control), 80 micromol/L trans-10, cis-12 CLA, or 80 micromol/L cis-9, trans-11 CLA for 12 d. Ca transport was measured radio-isotopically. RNA was isolated from the cells, labeled, and hybridized to the Affymetrix U133 2.0 Plus arrays (n = 3). Data and functional analysis was preformed using Bioconductor. Using a minimum fold-change criterion of 1.6 and a false discovery rate criterion of P-value <or= 0.05, trans-10, cis-12 CLA altered the expression of 918 genes, whereas, cis-9, trans-11 CLA had no effect on gene expression. Gene ontology analysis revealed that trans-10, cis-12 CLA strongly modulated a number of processes inherently related to carcinogenesis, such as cell cycle, cell proliferation, and DNA metabolism. Trans-10, cis-12 CLA, but not cis-9, trans-11 CLA, increased transepithelial Ca transport in Caco-2 cells, which corresponded to changes in molecular mediators of paracellular (including claudin 2 and 4) and transcellular (calbindin D(9)k and vitamin D receptor) Ca transport. This microarray-based study highlighted a number of gene expression patterns of relevance to 2 important intestinal processes (carcinogenesis and Ca transport), which were modulated by trans-10, cis-12 CLA. These may help our mechanistic understanding of the role of CLA in promoting gut function and health.

Acute and chronic effects of dietary fatty acids on cholecystokinin expression, storage and secretion in enteroendocrine STC‐1 cells

“…We do note divergent gene expression patterns with CLA 10,12 incubations resulting in a reduction of CCK mRNA transcript at both time frames whereas CLA 9,11 consistently up-regulated CCK mRNA levels. This is not surprising as CLA isomer-specific effects have been documented on gene expression patterns in intestinal cell lines [54].…”

The effect of trans-10, cis-12 conjugated linoleic acid on gene expression profiles related to lipid metabolism in human intestinal-like Caco-2 cells

“…Among these EGs, 406 (44.2%) were up-regulated and 512 (55.8%) were down-regulated. We have previously validated the microarray data by confirming the altered expression of seven key genes using quantitative RT-PCR [41].…”

“…In our previous study, global gene expression analysis showed that chronic supplementation of Caco-2 cells with the trans-10, cis-12 CLA isomer had profound effects on gene expression, whereas the cis-9, trans-11 isomer (the most abundant natural isomer) had no effect [41]. While particular emphasis was given to gene expression patterns of relevance to carcinogenesis and calcium transport, for which functional data exists, a number of wide-ranging biological processes of relevance to the intestine were modulated by trans-10, cis-12 CLA [41].…”

“…Microarray quality control and statistical validation were performed using Bioconductor [14]. A more detailed [22] description of the statistical analysis performed has been described elsewhere [41]. The list of differentially expressed genes was generated using a false discovery rate of 0.05 together with an absolute fold-change (fc) threshold of 1.6 (i.e.…”

“…While particular emphasis was given to gene expression patterns of relevance to carcinogenesis and calcium transport, for which functional data exists, a number of wide-ranging biological processes of relevance to the intestine were modulated by trans-10, cis-12 CLA [41]. In particular, genes related to the process of lipid metabolism were found to be significantly altered.…”