The objective of this research is to study the transfer of free fatty acids (ffa) in the intestine at the molecular level, in order to elucidate the mechanisms by which ffa assimilation occurs. The ultimate aim of these studies is to learn how to control lipid assimilation by regulation of rate limiting processes. The proposed studies will address the gaps in our knowledge concerning the regulation of ffa transfer, both within the intestinal lumen and within the cytoplasm of the enterocyte. The approach used will be an integrated one, combining the techniques of purified model lipid systems with reconstituted systems of cell membranes and cytoplasmic components. Recent work has shown that during the course of intestinal lipid digestion, two product phase are formed, a micelle phase and a unilamellar vesicle phase. The proposed studies will use a fluorescence assay recently developed by the applicant to compare the kinetics of ffa transfer from these two distinct lipid phases to acceptor membranes, and to determine the molecular mechanisms and rate limiting steps by which transfer from each of these phases occurs. The majority of ffa within the enterocyte cytoplasm are bound to fatty acid binding protein(s) (FABP). Our preliminary studies have shown that when ffa are bound to FABP, the fatty acyl chain is highly constrained within a hydrophobic pocket. The proposed studies will continue to investigate the physical nature of the FABP binding site of ffa, and will characterize and compare ffa binding to FABP v. ffa binding to membranes, in order to assess the relative roles of these interactions in cellular ffa assimilation. A further goal is to systemically investigate the manner in which FABP modulates intracellular ffa transport. The studies will examine and compare and the transfer kinetics of ffa from model membranes and subcellular membranes to FABP, and from FABP to membranes, and will elucidate the precise role of FABP in inter- membrane ffa transfer in the enterocyte. An understanding of ffa assimilation at the molecular level will enable more effective treatment of several pathophysiological and drug-induced malabsorption syndromes, and will support the continued development of oral drug delivery systems.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29DK038389-02
Application #
3462555
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1987-05-01
Project End
1992-04-30
Budget Start
1988-05-01
Budget End
1989-04-30
Support Year
2
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Harvard University
Department
Type
Schools of Public Health
DUNS #
082359691
City
Boston
State
MA
Country
United States
Zip Code
02115
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
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
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Chon, Su-Hyoun; Douglass, John D; Zhou, Yin Xiu et al. (2012) Over-expression of monoacylglycerol lipase (MGL) in small intestine alters endocannabinoid levels and whole body energy balance, resulting in obesity. PLoS One 7:e43962
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Lagakos, William Stacy; Gajda, Angela Marie; Agellon, Luis et al. (2011) Different functions of intestinal and liver-type fatty acid-binding proteins in intestine and in whole body energy homeostasis. Am J Physiol Gastrointest Liver Physiol 300:G803-14
Siddiqi, Shahzad; Saleem, Umair; Abumrad, Nada A et al. (2010) A novel multiprotein complex is required to generate the prechylomicron transport vesicle from intestinal ER. J Lipid Res 51:1918-28
Montero-Moran, Gabriela; Caviglia, Jorge M; McMahon, Derek et al. (2010) CGI-58/ABHD5 is a coenzyme A-dependent lysophosphatidic acid acyltransferase. J Lipid Res 51:709-19

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