肿瘤坏死因子-α(TNF-α)与肥胖

Research Advances in the Relationships betweent Tumor Necrosis Factor-α and Obesity

肿瘤坏死因子 ( Tumor Necrosis Factor,TNF)包括由活化的单核 /巨噬细胞产生的TNF- α和由活化的 T淋巴细胞产生的 TNF- β两种。二者在细胞来源、相对分子量、等电点、糖含量等方面有很大差别。 TNF-α是一种具有多种生物学活性的细胞因子 ,由 1 40 - 1 5 0个氨基酸残基组成 ,其中有两个反平行β片层 ,每个β片层有 5个β折叠。它由 TNFRI和 TNFRII两种受体组成 ,二者胞内结构区的同源性极低 ( 2 7% ) ,可能启动不同的生物学反应。研究发现TNF- α是与肥胖相关的蛋白质之一 ,对脂肪代谢具有重要调节作用。TNF- α通过抑制进食、增加机体产热量 ;促进脂肪分解、抑制脂肪合成 ;诱导产生瘦素 ;引起胰岛素抑制、抑制前脂肪细胞分化 ;诱导前脂肪细胞及脂肪细胞凋亡等作用调节脂肪代谢和能量平衡。同时 ,TNF- α在肥胖动物或人的脂肪组织中过量表达 。

There are two type of tumor necrosis factors(TNFs). TNF-α is produced by activited single nucleus cell or macrophage and TNF-β is produced by activited T lymphocytes.Many charaeteristics, sources, MW, PI, and carbonhydrate content, of this two TNFs are singificantly different. TNF-α, a kind of cellular factor with many biological activity, is composed of 140-150 amino acid residues, which form two antiparallel β-layers and every β-layer contains five β fold structure. TNF-α has two kind of receptors, TNFRI and TNFRII which has little homologous domain in cell (27%) and might activite different biological response. It has been proved that TNF-α is one of the proteins related to obesity, and it played a key role in regulating of fat metabolism. TNF-α regulates fat metabolism and body energy balance through suppressing food intake and increasing body heat production, suppressing fat synthesis, inducing leptin production and insulin suppression, promoting proadipocyte differentiation and inducing apoptosis of proadipocyte and adipocyte. Overexpression of TNF-α in adipocity tissue may also result in many side-effects toobese animal or human.