脂肪酸结合蛋白缺失及转基因小鼠的脂质代谢和脂肪因子水平
Lipid metabolism and adipokine levels in fatty acid-binding protein null and transgenic mice.
作者信息
Hertzel Ann V, Smith Lisa Ann, Berg Anders H, Cline Gary W, Shulman Gerald I, Scherer Philipp E, Bernlohr David A
机构信息
Dept. of Biochemistry, Molecular Biology, and Biophysics, Univ. of Minnesota, 321 Church St. SE, Minneapolis, MN 55455, USA.
出版信息
Am J Physiol Endocrinol Metab. 2006 May;290(5):E814-23. doi: 10.1152/ajpendo.00465.2005. Epub 2005 Nov 22.
Fatty acid-binding proteins (FABPs) facilitate the diffusion of fatty acids within cellular cytoplasm. Compared with C57Bl/6J mice maintained on a high-fat diet, adipose-FABP (A-FABP) null mice exhibit increased fat mass, decreased lipolysis, increased muscle glucose oxidation, and attenuated insulin resistance, whereas overexpression of epithelial-FABP (E-FABP) in adipose tissue results in decreased fat mass, increased lipolysis, and potentiated insulin resistance. To identify the mechanisms that underlie these processes, real-time PCR analyses indicate that the expression of hormone-sensitive lipase is reduced, while perilipin A is increased in A-FABP/aP2 null mice relative to E-FABP overexpressing mice. In contrast, de novo lipogenesis and expression of genes encoding lipoprotein lipase, CD36, long-chain acyl-CoA synthetase 5, and diacylglycerol acyltransferase are increased in A-FABP/aP2 null mice relative to E-FABP transgenic animals. Consistent with an increase in de novo lipogenesis, there was an increase in adipose C16:0 and C16:1 acyl-CoA pools. There were no changes in serum free fatty acids between genotypes. Serum levels of resistin were decreased in the E-FABP transgenic mice, whereas serum and tissue adiponectin were increased in A-FABP/aP2 null mice and decreased in E-FABP transgenic animals; leptin expression was unaffected. These results suggest that the balance between lipolysis and lipogenesis in adipocytes is remodeled in the FABP null and transgenic mice and is accompanied by the reprogramming of adipokine expression in fat cells and overall changes in plasma adipokines.
脂肪酸结合蛋白(FABPs)促进脂肪酸在细胞质内的扩散。与维持高脂饮食的C57Bl/6J小鼠相比,脂肪型脂肪酸结合蛋白(A-FABP)基因敲除小鼠表现出脂肪量增加、脂肪分解减少、肌肉葡萄糖氧化增加以及胰岛素抵抗减弱,而脂肪组织中上皮型脂肪酸结合蛋白(E-FABP)的过表达则导致脂肪量减少、脂肪分解增加和胰岛素抵抗增强。为了确定这些过程背后的机制,实时定量PCR分析表明,与E-FABP过表达小鼠相比,A-FABP/aP2基因敲除小鼠中激素敏感性脂肪酶的表达降低,而围脂滴蛋白A增加。相反,与E-FABP转基因动物相比,A-FABP/aP2基因敲除小鼠中从头脂肪生成以及编码脂蛋白脂肪酶、CD36、长链脂酰辅酶A合成酶5和二酰甘油酰基转移酶的基因表达增加。与从头脂肪生成增加一致,脂肪组织中C16:0和C16:1酰基辅酶A池增加。不同基因型之间血清游离脂肪酸没有变化。E-FABP转基因小鼠中抵抗素的血清水平降低,而A-FABP/aP2基因敲除小鼠中血清和组织脂联素增加,E-FABP转基因动物中血清和组织脂联素减少;瘦素表达不受影响。这些结果表明,在FABP基因敲除和转基因小鼠中,脂肪细胞中脂肪分解和脂肪生成之间的平衡被重塑,并伴随着脂肪细胞中脂肪因子表达的重新编程以及血浆脂肪因子的整体变化。