Unravelling the Functions of Fatty Acid Binding Proteins (FABPs) Expressed in Enterocyte.

RODRIGUEZ SAWICKI L; FALOMIR LOCKHART LJ; BOTASSO N; FRANCHINI GR; STORCH, J; CÓRSICO, B

Banff

Congreso; 53rd International Conference on the Bioscience of Lipids (ICBL); 2012

ICBL

Fatty acid (FA) are important to the cell as a source of energy, substrates for membrane biogenesis and signals for metabolic regulation and gene expression; acting on cell growth and survival, inflammatory and metabolic responses. Lipid hydrolysis in the intestinal lumen releases great quantities of FAs. Once inside the enterocyte, FAs are reversibly bound to two homologous proteins, expressed in large concentration: I- and LFABP. It has long been hypothesized that FABPs are essential to the intracellular transport and processing of the large quantities of FA absorbed by the intestine. Nevertheless, their precise functions are not fully understood. The present work evaluates FABP´s specific roles in enterocyte´s cell biology employing two different strategies: Functional analysis of enterocyte FABPs using cultured cells. A Caco-2 cell line with LFABP´s ablated expression was obtained, and shows marked variations in FA assimilation and distribution; cell proliferation and differentiation are also affected. The administration of FAs to Caco-2 cells induces the production of inflammatory cytokines´ mRNA. The participation of FABPs in the inflammatory response is also under study. Analysis of FABP-protein interactions. The interacting protein partners for intestinal FABPs are still unknown. As a first approach we have analyzed the mechanism of FA transfer between I- and LFABP, employing a fluorescence-based assay. This studies suggest that I- and LFABP may interact in order to exchange their cargo. In addition Far Western analysis of 2D electrophoresis from Caco-2 homogenates were performed, employing LFABP as probe. Spots that indicate LFABP´s interaction with other proteins were detected and are currently being analyzed using mass spectrometry. The information obtained combining protein-protein interactions with metabolic and inflammatory processes will contribute to assess intestinal FABPs specific functions and importance in the enterocyte.