Metallothionein-IIAPromoter Induction Alters Rat Intestinal Fatty Acid Binding Protein Expression, Fatty Acid Uptake, and Lipid Metabolism in Transfected L-Cells Academic Article uri icon

abstract

  • Mouse L-cell fibroblasts, transfected with the cDNA encoding for rat intestinal fatty acid-binding protein (I-FABP) under the control of the human metallothionein-IIA promoter, were tested for their protein inducibility by the heavy metals cadmium (Cd2+) and zinc (Zn2+). I-FABP levels were quantitated by Western immunoblotting. Expression of I-FABP in all transfected cell lines tested was induced several-fold by optimized levels of Cd2+ and Zn2+. Induction conditions had no effect on cell growth rates or cell densities for any of the cell lines. Induction of high I-FABP-expressing cells (H141) decreased the initial rate and extent of uptake of cis-parinaric acid, a nonmetabolizable fatty acid, and of [3H]oleic acid, an esterifiable fatty acid. These effects of induction were specific for I-FABP-expressing cells since they were not observed in control cells or cells expressing a high level of liver (L-) FABP. Induction of H141 cells also significantly altered the esterification and distribution of exogenous [3H]oleic acid, especially among triglycerides and phosphatidylcholine, but less so among other glycero-phospholipids, cholesteryl esters, and phosphatidylethanolamine. Induction of H141 cells normalized [3H]oleic acid esterification into cholesteryl esters, phosphatidylcholine, total neutral lipids, and total phospholipids such that they no longer differed from control levels. In contrast, induction did not normalize [3H]oleic acid esterification into triacylglycerols and phosphatidylethanolamine to control levels in H141 cells; both remained significantly increased over control cells. Therefore, promoter induction levels of Cd2+ and Zn2+ enhanced I-FABP expression in H141 cells, thereby modulating both fatty acid uptake and intracellular esterification into neutral and phospholipids.

author list (cited authors)

  • Prows, D. R., & Schroeder, F.

citation count

  • 30

complete list of authors

  • Prows, DR||Schroeder, F

publication date

  • April 1997