Fatty acids (ffa) and monoacylglycerol (MG) are the major digestive products of dietary lipid. The intestine presents a barrier through which the ffa and MG must pass, yet the mechanisms by which they are transported remain largely unresolved. The objective of this research plan is to continue to address the gaps in our knowledge of the molecular mechanisms of ffa transfer a) from the two lipid phases present in the intestinal lumen, micelles and vesicles, to the enterocyte; b) across the microvillus membrane (MVM) of the intestinal cell; and c) within the enterocyte cytoplasm. The latter studies will focus on the functions of intestinal and liver fatty acid binding proteins (I- and L-FABP). These are thought to play a role in intracellular ffa transport, but their precise functions remain unknown. The proposed studies will also begin to analyze the kinetics and mechanism of MG absorption. The experimental approach will combine the use of purified model lipid systems, reconstituted systems of cell membranes and cytoplasmic components, and the Caco-2 intestinal cell culture system. Two product phases are now known to be formed during the course of intestinal lipid digestion, a micelle phase and a vesicle phase. The kinetics of ffa and MG transfer from the two phases will be studied using fluorescent ffa and MG derivatives, and a resonance energy transfer assay. Studies will continue to define the mechanisms of transfer from each of these phases, their relative contributions to lipid uptake, and their regulation by structural and physiologically important solution variables. The mechanism by which ffa cross the MVM is presently controversial, and little is known about intestinal MG uptake. To determine the role of plasma membrane protein vs. lipid diffusion pathways, studies will use fluorescence microscopy to directly monitor the transmembrane transport of ffa and MG at the level of the single Caco-2 cell. In order to define the role that I- and L-FABP play in ffa assimilation, the proposed studies will use the protein fluorescence of the FABP and a series of fluorescent ffa derivatives, to compare the structural interactions with ffa for I-FABP vs. L-FABP. Interactions with MG will also be examined for the first time. The proposed studies will also systematically analyze the mechanisms of ffa and MG transfer from I- vs. L-FABP to model and subcellular membranes, and the role of these FABP in intermembrane ffa traffic in the enterocyte. Both fluorescent and natural ligands will be used for these investigations. A better understanding of the molecular mechanisms underlying ffa and MG assimilation in the intestine may enable more effective treatment of malabsorption syndromes, the continued development of enteral drug delivery systems, and the regulation of dietary energy utilization.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK038389-10
Application #
2140500
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1987-05-01
Project End
1997-04-30
Budget Start
1995-08-15
Budget End
1996-04-30
Support Year
10
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Rutgers University
Department
Nutrition
Type
Schools of Earth Sciences/Natur
DUNS #
038633251
City
New Brunswick
State
NJ
Country
United States
Zip Code
08901
Dasilva, Gabriel; Boller, Matthew; Medina, Isabel et al. (2018) Relative levels of dietary EPA and DHA impact gastric oxidation and essential fatty acid uptake. J Nutr Biochem 55:68-75
Onishi, Janet C; Campbell, Sara; Moreau, Michael et al. (2017) Bacterial communities in the small intestine respond differently to those in the caecum and colon in mice fed low- and high-fat diets. Microbiology 163:1189-1197
McCauliff, Leslie A; Storch, Judith (2017) Transport Assays for Sterol-Binding Proteins: Stopped-Flow Fluorescence Methods for Investigating Intracellular Cholesterol Transport Mechanisms of NPC2 Protein. Methods Mol Biol 1583:97-110
Wang, Qian; Rizk, Samar; Bernard, C├ędric et al. (2017) Protocols and pitfalls in obtaining fatty acid-binding proteins for biophysical studies of ligand-protein and protein-protein interactions. Biochem Biophys Rep 10:318-324
McCauliff, Leslie A; Xu, Zhi; Li, Ran et al. (2015) Multiple Surface Regions on the Niemann-Pick C2 Protein Facilitate Intracellular Cholesterol Transport. J Biol Chem 290:27321-31
Douglass, John D; Zhou, Yin Xiu; Wu, Amy et al. (2015) Global deletion of MGL in mice delays lipid absorption and alters energy homeostasis and diet-induced obesity. J Lipid Res 56:1153-71
Gajda, Angela M; Storch, Judith (2015) Enterocyte fatty acid-binding proteins (FABPs): different functions of liver and intestinal FABPs in the intestine. Prostaglandins Leukot Essent Fatty Acids 93:9-16
Park, Woo-Jae; Park, Joo-Won; Merrill, Alfred H et al. (2014) Hepatic fatty acid uptake is regulated by the sphingolipid acyl chain length. Biochim Biophys Acta 1841:1754-66
Ilnytska, Olha; Santiana, Marianita; Hsu, Nai-Yun et al. (2013) Enteroviruses harness the cellular endocytic machinery to remodel the host cell cholesterol landscape for effective viral replication. Cell Host Microbe 14:281-93
Gajda, Angela M; Zhou, Yin Xiu; Agellon, Luis B et al. (2013) Direct comparison of mice null for liver or intestinal fatty acid-binding proteins reveals highly divergent phenotypic responses to high fat feeding. J Biol Chem 288:30330-44

Showing the most recent 10 out of 26 publications