Bile acids regulate the ontogenic expression of ileal bile acid binding protein in the rat via the farnesoid X receptor

Molecular mechanisms of the bile acid active transport system in the ileal enterocytes remain unknown. We examined whether bile acids affect human enterocyte gene expression of intestinal bile acid-binding protein (I-BABP), a component of this transport system. Differentiated Caco-2 cells were incubated in the presence of human bile, bile acids or other lipids. The level of I-BABP expression was evaluated by Northern and Western blot analyses. A 24 h incubation of Caco-2 cells in a medium containing either bile or bile acids resulted in a remarkable 7.5-fold increase in the I-BABP mRNA level over the control level. Neither cholesterol, palmitic acid, phosphatidylcholine nor cholestyramine treated bile showed any difference in I-BABP mRNA expression from the control. Bile acid treatment increased the level of I-BABP mRNA in Caco-2 cells in a time- and dose-dependent manner. Western blot analysis showed that this induction led to increase in cytosolic I-BABP. Chenodeoxycholic acid and deoxycholic acid showed greater induction effects than other hydrophilic bile acids, including their own glycine conjugates. Pretreatment by actinomycin D or cycloheximide completely inhibited the up-regulation of I-BABP expression by bile acid. Bile acids, especially lipophilic bile acids, increase the I-BABP expression in Caco-2-cells, suggesting that luminal bile acids play an important role in regulating the I-BABP gene expression.

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NMR-based modeling and binding studies of a ternary complex between chicken liver bile acid binding protein and bile acids

Proteins Structure Function and Bioinformatics ◽

10.1002/prot.21517 ◽

2007 ◽

Vol 69 (1) ◽

pp. 177-191 ◽

Cited By ~ 22

Author(s):

Simona Tomaselli ◽

Laura Ragona ◽

Lucia Zetta ◽

Michael Assfalg ◽

Pasquale Ferranti ◽

...

Keyword(s):

Bile Acid ◽

Bile Acids ◽

Ternary Complex ◽

Binding Protein ◽

Chicken Liver ◽

Binding Studies ◽

Acid Binding Protein ◽

Bile Acid Binding

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Validation of Recombinant Chicken Liver Bile Acid Binding Protein as a Tool for Cholic Acid Hosting

Biomolecules ◽

10.3390/biom11050645 ◽

2021 ◽

Vol 11 (5) ◽

pp. 645

Author(s):

Giusy Tassone ◽

Maurizio Orlandini ◽

Massimo Olivucci ◽

Cecilia Pozzi

Keyword(s):

Bile Acid ◽

High Resolution ◽

Affinity Chromatography ◽

Bile Acids ◽

Drug Carriers ◽

Chicken Liver ◽

Purification Procedure ◽

Acid Binding Protein ◽

Bile Acid Binding ◽

Exogenous Substances

Bile acids (BAs) are hydroxylated steroids derived from cholesterol that act at the intestinal level to facilitate the absorption of several nutrients and also play a role as signaling molecules. In the liver of various vertebrates, the trafficking of BAs is mediated by bile acid-binding proteins (L-BABPs). The ability to host hydrophobic or amphipathic molecules makes BABPs suitable for the distribution of a variety of physiological and exogenous substances. Thus, BABPs have been proposed as drug carriers, and more recently, they have also been employed to develop innovative nanotechnology and biotechnology systems. Here, we report an efficient protocol for the production, purification, and crystallization of chicken liver BABP (cL-BABP). By means of target expression as His6-tag cL-BABP, we obtained a large amount of pure and homogeneous proteins through a simple purification procedure relying on affinity chromatography. The recombinant cL-BABP showed a raised propensity to crystallize, allowing us to obtain its structure at high resolution and, in turn, assess the structural conservation of the recombinant cL-BABP with respect to the liver-extracted protein. The results support the use of recombinant cL-BABP for the development of drug carriers, nanotechnologies, and innovative synthetic photoswitch systems.

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