Knockdown of Macrophage Migration Inhibitory Factor Disrupts Adipogenesis in 3T3-L1 Cells
Knockdown of Macrophage Migration Inhibitory Factor Disrupts Adipogenesis in 3T3-L1 Cells
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DOI：
10.1210/en.2008-0158
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发表时间：
2008-12-01
期刊：
影响因子：
4.8
通讯作者：
Nishimura, Masaharu
中科院分区：
文献类型：
--
作者：
Ikeda, Daisuke;Sakaue, Shinji;Nishimura, Masaharu
肥胖是脂肪组织体积扩大的一种情况。脂肪细胞大小和数量的增加有助于脂肪组织的扩大。细胞数量的增加被认为是由前脂肪细胞的增殖和分化引起的。巨噬细胞迁移抑制因子（Macrophage migration inhibitory factor， MIF）在脂肪细胞中表达，在脂肪形成过程中细胞内MIF含量增加。因此，我们假设MIF与脂肪形成过程中的脂肪细胞生物学有关，并重点研究了MIF对脂肪形成的影响。为了研究MIF对脂肪细胞的影响，通过RNA干扰抑制3T3-L1前脂肪细胞中MIF的表达，并通过标准程序诱导细胞分化。转染MIF小干扰RNA （siRNA）的3T3-L1细胞甘油三酯含量低于转染非特异性siRNA的细胞。此外，MIF敲除明显消除了分化过程中脂联素mRNA水平的增加。转染MIF siRNA后，过氧化物酶体增殖物活化受体(PPAR) γ、CCAAT/增强子结合蛋白(C/EBP) α和C/EBP δ基因表达降低，但C/EBP β基因表达升高。转染MIF siRNA的细胞在诱导分化后1-3 d细胞数量减少，14-20 h细胞内5-溴-2-脱氧尿苷掺入减少，提示MIF siRNA抑制有丝分裂克隆扩增。综上所述，这些结果表明，MIF通过抑制有丝分裂克隆扩增和/或C/EBP δ表达，至少部分地调节3T3-L1前脂肪细胞的分化。（内分泌学149:6037-6042,2008）
Obesity is a condition in which adipose tissue mass is expanded. Increases in both adipocyte size and number contribute to enlargement of adipose tissue. The increase in cell number is thought to be caused by proliferation and differentiation of preadipocytes. Macrophage migration inhibitory factor (MIF) is expressed in adipocytes, and intracellular MIF content is increased during adipogenesis. Therefore, we hypothesized that MIF is associated with adipocyte biology during adipogenesis and focused on the influence of MIF on adipogenesis. To examine the effects of MIF on adipocytes, MIF expression in 3T3-L1 preadipocytes was inhibited by RNA interference, and cell differentiation was induced by standard procedures. The triglyceride content of MIF small interfering RNA (siRNA)-transfected 3T3-L1 cells was smaller than that of nonspecific siRNA-transfected cells. In addition, MIF knockdown apparently abrogated increases in adiponectin mRNA levels during differentiation. Gene expression of peroxisome proliferator-activated receptor (PPAR)gamma, CCAAT/enhancer binding protein (C/EBP)alpha, and C/EBP delta decreased with MIF siRNA transfection, butC/EBP beta expression increased. Cell number and incorporation of 5-bromo-2-deoxyuridine into cells decreased from 1-3 d and from 14-20 h, respectively, after induction of differentiation in MIF siRNA-transfected cells, thus suggesting that MIF siRNA inhibits mitotic clonal expansion. Taken together, these results indicated that MIF regulates differentiation of 3T3-L1 preadipocytes, at least partially, through inhibition of mitotic clonal expansion and/or C/EBP delta expression. (Endocrinology 149: 6037-6042, 2008)