Fatty acid-binding protein

About: Fatty acid-binding protein is a research topic. Over the lifetime, 1721 publications have been published within this topic receiving 81530 citations. The topic is also known as: FABP.

Liver fatty acid binding protein gene ablation enhances age-dependent weight gain in male mice

Abstract: Although studies performed in vitro and with transfected cells in culture suggest a role for liver fatty acid binding protein (L-FABP) in regulating fatty acid oxidation and fat deposition, the physiological significance of this possibility is not completely clear. To begin to address this question, the effect of L-FABP gene ablation on phenotype of standard rodent chow-fed male mice was examined with increasing age up to 18 months. While young (2-3 months old) L-FABP null mice displayed no visually obvious phenotype, with increasing age >9 months the L-FABP null mice were visibly larger, exhibiting increased body weight due to increased fat and lean tissue mass. Liver lipid concentrations were unaffected by L-FABP gene ablation with the exception of triacylglycerol, which was decreased by 74% in the livers of 3-month-old mice. Likewise, serum lipid levels were not altered in L-FABP null mice with the exception of triacylglycerol, which was increased in the serum of 18-month-old mice. Increased body weight, fat tissue mass, and lean tissue mass in 18-month-old L-FABP null mice were accompanied by increased hepatic levels of low-density lipoprotein (LDL) receptor, peroxisome proliferator-activated receptor (PPAR) alpha, and PPARalpha-regulated proteins such as fatty acid transport protein (FATP), fatty acid translocase (FAT/CD36), carnitine palmitoyl transferase I (CPT I), and lipoprotein lipase (LPL). A key enzyme in cholesterol biosynthesis, 3-hydroxy-3-methylglutaryl Coenzyme A (HMG-CoA) reductase, was down-regulated in L-FABP null mice. These findings were consistent with a proposed role for L-FABP as an important physiological regulator of PPARalpha.

Liver and intestinal fatty acid-binding protein expression increases phospholipid content and alters phospholipid fatty acid composition in L-cell fibroblasts.

Abstract: Although fatty acid-binding proteins (FABP) differentially affect fatty acid uptake, nothing is known regarding their role(s) in determining cellular phospholipid levels and phospholipid fatty acid composition. The effects of liver (L)- and intestinal (I)-FABP expression on these parameters were determined using stably transfected L-cells. Expression of L- and I-FABP increased cellular total phospholipid mass (nmol/mg protein) 1.7- and 1.3-fold relative to controls, respectively. L-FABP expression increased the masses of choline glycerophospholipids (ChoGpl) 1.5-fold, phosphatidylserine (PtdSer) 5.6-fold, ethanolamine glycerophospholipids 1.4-fold, sphingomyelin 1.7-fold, and phosphatidylinositol 2.6-fold. In contrast, I-FABP expression only increased the masses of ChoGpl and PtdSer, 1.2- and 3.1-fold, respectively. Surprisingly, both L- and I-FABP expression increased ethanolamine plasmalogen mass 1.6- and 1.1-fold, respectively, while choline plasmalogen mass was increased 2.3- and 1.7-fold, respectively. The increase in phospholipid levels resulted in dramatic 48 and 33% decreases in the cholesterol-to-phospholipid ratio in L- and I-FABP expressing cells, respectively. L-FABP expression generally increased polyunsaturated fatty acids, primarily by increasing 20:4n-6 and 22:6n-3, while decreasing 18:1n-9 and 16:1n-7. I-FABP expression generally increased only 20:4n-6 proportions. Hence, expression of both I- and L-FABP differentially affected phospholipid mass, class composition, and acyl chain composition. Although both proteins enhanced phospholipid synthesis, the effect of L-FABP was much greater, consistent with previous work suggesting that these two FABP differentially affect lipid metabolism.