Fatty Acid Binding Proteins-Ligand Specificity

描述(申请人提供)：长链脂肪酸(LCFA)和LCFA-COA是脂代谢的重要代谢中间体，也是参与LCFA、脂蛋白和/或葡萄糖代谢的核转录因子(PPARpha、HNF4pha)的配体调节者。尽管对纯化的脂肪酸结合蛋白(FABP)在体外和/或在培养中过表达的转化细胞的研究表明，FABP在LCFA代谢中起作用，但单个FABP在体内的生理作用尚未解决。肝细胞(肝细胞)大量表达三种与LCFA和LCFA-COA结合的蛋白质：肝脏脂肪酸结合蛋白(L-FABP)、固醇携带蛋白-2(SCP-2)和固醇携带蛋白-x(SCP-x)。本应用的目的是：(I)消除LCFA/LCFA-CoA结合蛋白的单独合成，并在有指示的情况下，在基因去除的小鼠中增殖；(Ii)检测这些蛋白质在培养肝细胞和体内直链和支链LCFA代谢中的单独作用(S)；以及(Iii)研究LCFA/LCFA-CoA结合蛋白可能发挥作用的两种潜在的核调控机制(S)。具体目标集中在培养的肝细胞和基因靶向的小鼠身上，以检查： 目的1.LCFA在转基因小鼠肝细胞和体内肝细胞中的摄取及细胞内转运。 目的2.L-FABP、LCFAs/LCFA-COAS在对照组和基因剔除小鼠肝细胞中的胞核转运、分布及其与PPARα和HNF4α的相互作用。 目的3.基因去除小鼠和体内培养肝细胞线粒体、过氧化物体和内质网中低分子脂肪酸的氧化。 目的4.去基因小鼠肝细胞和体内培养肝细胞的酯化储存或分泌。 随着人们对细胞内脂肪酸和葡萄糖代谢之间相互关系的认识日益加深，这些研究的结果将有助于我们了解糖尿病以及脂代谢疾病的相关因素，包括动脉粥样硬化、肥胖和心脏病。

DESCRIPTION (provided by applicant): Long chain fatty acids (LCFAs) and LCFA-CoAs serve as important metabolic intermediates in lipid metabolism and as ligand regulators of nuclear transcription factors (PPARalpha, HNF4alpha) involved in LCFA, lipoprotein, and/or glucose metabolism. Although studies with purified fatty acid binding proteins (FABPs) in vitro and/or with overexpressed, transformed cells in culture suggest functions in LCFA metabolism, physiological roles of individual FABPs in vivo are unresolved. Liver cells (hepatocytes) express three proteins in abundance that bind both LCFAs and LCFA-CoAs: liver fatty acid-binding protein (L-FABP), sterol carrier protein-2 (SCP-2), and sterol carrier protein-x (SCP-x). The objective of this application is to: (i) eliminate synthesis of LCFA/LCFA-CoA binding proteins individually, and where indicated, multiply in gene-ablated mice; (ii) examine individual role(s) of these proteins in metabolism of straight- and branched-chain LCFAs in cultured hepatocytes and in vivo; and (iii) examine two potential nuclear regulatory mechanism(s) whereby the LCFA/LCFA-CoA binding proteins may exert effects. The specific aims are focused on cultured hepatocyes and gene-targeted mice to examine: Aim 1. LCFA uptake and intracellular LCFA/LCFA-CoA transport in hepatocytes cultured from gene-ablated mice and in vivo. Aim 2. Trafficking of L-FABP, LCFAs/LCFA-CoAs to nuclei, distribution within nuclei, and interaction with PPARalpha and HNF4alpha in cultured hepatocytes from control and gene-ablated mice. Aim 3. Oxidation of LCFAs in mitochondria, peroxisomes, and endoplasmic reticulum of cultured hepatocytes from gene-ablated mice and in vivo. Aim 4. Esterification for storage or secretion in cultured hepatocytes from gene-ablated mice and in vivo. With the growing awareness of interrelationships between intracellular fatty acid and glucose metabolism, results from these studies will contribute to our understanding of factors involved in diabetes as well as diseases of lipid metabolism, including atherosclerosis, obesity, and heart disease.