Research of an in vitro model to study the expression of fatty acid-binding proteins in the small intestine

1993 ◽  
pp. 85-92
Author(s):  
Anne Mallordy ◽  
Philippe Besnard ◽  
Hélène Carlier
Keyword(s):  
Small Intestine ◽  
Fatty Acid ◽  
Binding Proteins ◽  
In Vitro Model ◽  
Fatty Acid Binding Proteins ◽  
Fatty Acid Binding ◽  
Vitro Model

scholarly journals Functional analysis of peroxisome-proliferator-responsive element motifs in genes of fatty acid-binding proteins

2004 ◽  
Vol 382 (1) ◽  
pp. 239-245 ◽  
Author(s):  
Christian SCHACHTRUP ◽  
Tanja EMMLER ◽  
Bertram BLECK ◽  
Anton SANDQVIST ◽  
Friedrich SPENER
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Binding Proteins ◽  
Lipid Binding ◽  
Fatty Acid Binding Proteins ◽  
Computer Search ◽  
Peroxisome Proliferator ◽  
Fatty Acid Binding ◽  
Responsive Element

Retinoic acids and long-chain fatty acids are lipophilic agonists of nuclear receptors such as RXRs (retinoic X receptors) and PPARs (peroxisome-proliferator-activated receptors) respectively. These agonists are also ligands of intracellular lipid-binding proteins, which include FABPs (fatty acid-binding proteins). We reported previously that L (liver-type)-FABP targets fatty acids to the nucleus of hepatocytes and affects PPARα activation, which binds together with an RXR subtype to a PPRE (peroxisome-proliferator-responsive element). In the present study, we first determined the optimal combination of murine PPAR/RXR subtypes for binding to known murine FABP-PPREs and to those found by computer search and then tested their in vitro functionality. We show that all PPARs bind to L-FABP-PPRE, PPARα, PPARγ1 and PPARγ2 to A (adipocyte-type)-FABP-PPRE. All PPAR/RXR heterodimers transactivate L-FABP-PPRE, best are combinations of PPARα with RXRα or RXRγ. In contrast, PPARα heterodimers do not transactivate A-FABP-PPRE, best combinations are of PPARγ1 with RXRα and RXRγ, and of PPARγ2 with all RXR subtypes. We found that the predicted E (epidermal-type)- and H (heart-type)-FABP-PPREs are not activated by any PPAR/RXR combination without or with the PPAR pan-agonist bezafibrate. In the same way, C2C12 myoblasts transfected with promoter fragments of E-FABP and H-FABP genes containing putative PPREs are also not activated through stimulation of PPARs with bezafibrate applied to the cells. These results demonstrate that only PPREs of L- and A-FABP promoters are functional, and that binding of PPAR/RXR heterodimers to a PPRE in vitro does not necessarily predict transactivation.

scholarly journals Perfluoroalkyl Acid Binding with Peroxisome Proliferator-Activated Receptors α, γ, and δ, and Fatty Acid Binding Proteins by Equilibrium Dialysis with a Comparison of Methods

Toxics ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 45
Author(s):  
Manoochehr Khazaee ◽  
Emerson Christie ◽  
Weixiao Cheng ◽  
Mandy Michalsen ◽  
Jennifer Field ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Chain Length ◽  
Binding Proteins ◽  
Equilibrium Dialysis ◽  
Short Chain ◽  
Fatty Acid Binding Proteins ◽  
Peroxisome Proliferator ◽  
Binding Affinities ◽  
Fatty Acid Binding

The biological impacts of per- and polyfluorinated alkyl substances (PFAS) are linked to their protein interactions. Existing research has largely focused on serum albumin and liver fatty acid binding protein, and binding affinities determined with a variety of methods show high variability. Moreover, few data exist for short-chain PFAS, though their prevalence in the environment is increasing. We used molecular dynamics (MD) to screen PFAS binding to liver and intestinal fatty acid binding proteins (L- and I-FABPs) and peroxisome proliferator activated nuclear receptors (PPAR-α, -δ and -γ) with six perfluoroalkyl carboxylates (PFCAs) and three perfluoroalkyl sulfonates (PFSAs). Equilibrium dissociation constants, KDs, were experimentally determined via equilibrium dialysis (EqD) with liquid chromatography tandem mass spectrometry for protein-PFAS pairs. A comparison was made between KDs derived from EqD, both here and in literature, and other in vitro approaches (e.g., fluorescence) from literature. EqD indicated strong binding between PPAR-δ and perfluorobutanoate (0.044 ± 0.013 µM) and perfluorohexane sulfonate (0.035 ± 0.0020 µM), and between PPAR-α and perfluorohexanoate (0.097 ± 0.070 µM). Unlike binding affinities for L-FABP, which increase with chain length, KDs for PPARs showed little chain length dependence by either MD simulation or EqD. Compared with other in vitro approaches, EqD-based KDs consistently indicated higher affinity across different proteins. This is the first study to report PPARs binding with short-chain PFAS with KDs in the sub-micromolar range.

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