title: Peroxisome proliferator enhances gene expression of cellular retinol-binding protein, type II in Caco-2 cells.
abstract: Both the mRNA and protein of cellular retinol-binding protein, type two (CRBP(II)) are induced in rat intestine by high fat (corn oil) diet (Biochim. Biophys. Acta 1200, 34-40, 1994) as well as by dietary unsaturated long-chain fatty acids (J. Nutr. 125, 2039-2044, 1995). To gain an insight into the mechanism for this induction, we investigated whether CRBP(II) gene was activated by exposure of the human intestinal cell line, Caco-2 to a peroxisome proliferator (clofibric acid) and/or 9-cis retinoic acid. Northern blot hybridization revealed that Caco-2 cells endogenously expressed the mRNAs of peroxisome proliferator-activated receptor alpha (PPARalpha) and retinoid X receptor alpha (RXRalpha). The expression of the genes encoding CRBP(II), PPARalpha, and RXRalpha increased progressively during differentiation of Caco-2 cells. The cells exposed to 100 microM clofibric acid exhibited 70% greater CRBP(II) mRNA and the exposure of the cells to 100 microM clofibric acid in combination with 100 microM 9-cis retinoic acid exhibited 130% greater CRBP(II) mRNA level, indicating that the effect of the combination of them was additive. Neither PPARalpha mRNA nor RXRalpha mRNA level was enhanced by clofibric acid. In conclusion, our data suggested that the CRBP(II) gene expression may be enhanced by an activation of PPARalpha-RXRalpha heterodimer through some putative metabolite(s) formed via fatty acid-related metabolic pathway in the clofibrc acid-treated cells.
authors.affiliation: Department of Nutrition, School of Food and Nutritional Sciences, The University of Shizuoka, Yada, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Suruga
authors.forename: T
authors.initials: T
authors.lastname: Goda
authors.forename: S
authors.initials: S
authors.lastname: Takase
mesh_terms: D000077556:Alitretinoin; D000818:Animals; D015152:Blotting, Northern; D018938:Caco-2 Cells; D002454:Cell Differentiation; D002995:Clofibric Acid / Q000494:pharmacology*; D003609:Dactinomycin / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D008830:Microbodies / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects; D018168:Receptors, Retinoic Acid / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000187:drug effects; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D014157:Transcription Factors; C082928:retinoic acid binding protein II, cellular; D003609:Dactinomycin; D000077556:Alitretinoin; D002995:Clofibric Acid; D014212:Tretinoin