Differential regulation of intestinal and liver fatty acid-binding proteins in human intestinal cell line (Caco-2): role of collagen.
Fatty acid-binding proteins (FABP) are small cytosolic proteins which are thought to play a key role in fatty acid metabolism. The intestine contains the intestinal (I-FABP) and the liver (L-FABP) isoforms, but their regulation is still poorly documented. In order to find suitable conditions for studying the regulation of the two FABP isoforms in Caco-2 cells, we investigated the effects of the presence of collagen during cell proliferation or differentiation. When collagen was present only during cell proliferation on culture dishes, I-FABP expression was enhanced, whereas sucrase-isomaltase was unaffected and L-FABP expression was merely accelerated. In contrast, when collagen was present during cell differentiation on filter inserts, both I-FABP and sucrase-isomaltase were strongly reduced, but L-FABP was not affected. Under the former conditions (the more suitable for studying FABP regulation), the peroxysome proliferator-activated receptor (PPAR) activators, clofibrate and alpha-bromopalmitate, enhanced the two isoforms. This study, which is the first one providing a quantitative protein analysis of I-FABP and L-FABP in Caco-2 cells, demonstrates different time courses of expression of these proteins during cell differentiation. It also shows that I-FABP is specifically regulated by collagen and that, under conditions optimal for their expression, both isoforms are modulated by metabolic factors.
Darimont
C
C
Metabolic and Cardiovascular Diseases, Novartis Pharma AG, Basel, CH-4002, Switzerland.
Gradoux
N
N
Cumin
F
F
Baum
H P
HP
De Pover
A
A
D015117:5,8,11,14-Eicosatetraynoic Acid / Q000494:pharmacology; D000906:Antibodies / Q000302:isolation & purification; D018938:Caco-2 Cells; D002352:Carrier Proteins / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D002994:Clofibrate / Q000494:pharmacology; D003094:Collagen / Q000502:physiology*; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D018996:Myelin P2 Protein / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D009363:Neoplasm Proteins; D010168:Palmitates / Q000494:pharmacology; D020033:Protein Isoforms / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism; D013394:Sucrase-Isomaltase Complex / Q000378:metabolism; D025521:Tumor Suppressor Proteins
D000906:Antibodies; D002352:Carrier Proteins; C493319:FABP1 protein, human; C107608:FABP7 protein, human; C493320:Fabp1 protein, mouse; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D018996:Myelin P2 Protein; D009363:Neoplasm Proteins; D010168:Palmitates; D020033:Protein Isoforms; D025521:Tumor Suppressor Proteins; D015117:5,8,11,14-Eicosatetraynoic Acid; C022776:2-bromopalmitate; D003094:Collagen; D013394:Sucrase-Isomaltase Complex; D002994:Clofibrate