EXPRESSION OF INTESTINAL FATTY-ACID-BINDING PROTEIN IN INTESTINAL EPITHELIAL-CELL LINES, HBRIE-380 CELLS

Intestinal fatty acid binding protein (I-FABP) is a cytosolic protein present only in differentiated intestinal epithelial cells. Here we re port on an intestinal cell culture system expressing I-FABP during cel l differentiation and the modulation of expression by extracellular fa ctors. An I-FABP-expressing cell line (hBRIE 380i) was generated from Berkeley rat intestinal epithelial cells (hBRIE 380). Time- and substr atum-dependent changes in I-FABP mRNA expression were paralleled by ch anges in protein levels. Induction of I-FABP levels observed on collag en type I gels in the presence of limiting serum was prevented by insu lin. When cells were grown on collagen gels containing fibronectin and laminin, a stimulation of ultrastructural characteristics of cell dif ferentiation was observed with no further induction of I-FABP expressi on. The data show that I-FABP expression is limited to a differentiate d population of hBRIE 380i cells and that the expression can be regula ted by factors present in the extracellular matrix as well as involved in regulation of replication or metabolic state of the cell.