Downregulation of lipid droplets formation in adipocyte by TGFβand identification of its regulator

我们研究了一种典型的免疫调节细胞因子，转化生长因子β(TGFβ)对脂肪细胞中脂滴积累和脂滴形成相关基因表达的影响。TGF-β诱导成熟的白色脂肪细胞（分化的HW11细胞）发生了显著的形态变化，并损害了脂滴的积累。在分化的HW11细胞中，tgf β显著降低了perilipin的表达。Perilipin是脂滴相关蛋白之一，是脂质储存的调节因子，也是ppar γ靶基因。tgf - β也降低了PPARγ的基因表达，但对PPARγ的活性没有影响。tgf β部分降低Smad3缺陷mef中PPARγmRNA的表达。上述结果提示，tgf β通过下调成熟白色脂肪细胞ppar γ的表达，负向调节periilipin的表达水平，从而诱导脂滴的形态改变，损害脂滴的聚集。

We examined the effect of a typical immunoregulatory cytokine, transforming growth factorβ(TGFβ) on the accumulation of lipid droplets and the expression of genes involved in their formation in adipocytes.TGF-βinduced the remarkable morphological change and impaired the accumulation of lipid droplets in mature white adipocytes(differentiated HW11 cells). In differentiated HW11 cells TGFβdramatically reduced the expression of perilipin. Perilipin, one of the lipid droplet-associated proteins, is a regulator of lipid storage and is also known to a PPARγtarget gene. TGFβalso reduced gene expression of PPARγbut not the activity of PPARγ. TGFβpartially reduced PPARγmRNA expression in Smad3 deficient MEFs. These findings suggest that TGFβinduces the morphological change and impairs the accumulation of lipid droplets by negatively regulating the expression level of perilipin through downregulation of the PPARγexpression in mature white adipocytes.