Abstract

Retinoid X receptor α (RXRα) is thought to be a key regulator in lipid metabolism, glucose metabolism, adipogenic differentiation, gene expression, and inflammatory response. However, it is not clear whether RXRα has any role in intramuscular preadipocyte of goat. In the current investigation, we report that adenovirus overexpression of RXRα promotes lipid accumulation in intramuscular adipocyte and up-regulates the expression of positive indicator genes (PPARγ and GLUT4). Next, knockdown of RXRα does not affect adipogenesis of intramuscular adipocyte. This phenomenon may be caused by the compensatory increase of RXRγ. In addition, we found that KLF8 mediates the positive role of RXRα. Knockdown of KLF8 by siRNA attenuated the effect of RXRα on adipocyte differentiation. Importantly, the promoter activity of KLF8 is enhanced when overexpression of RXRα. Taken together, our data suggest that RXRα promotes the differentiation of intramuscular preadipocytes in goat through targeting KLF8, but it could be replaced by RXRγ. These results provide new insights into the quality improvement of goat meat.

摘要

维甲酸 X 受体 α ( RXR α) 被认为是脂质代谢、葡萄糖代谢、成脂分化、基因表达和炎症反应的关键调节剂。然而，尚不清楚RXR α是否对山羊的肌内前脂肪细胞有任何作用。在目前的调查中，我们报告了RXR α 的腺病毒过表达促进了肌肉内脂肪细胞中的脂质积累并上调了阳性指示基因（PPAR γ 和GLUT 4）的表达。接下来，RXR α 的敲低不影响肌内脂肪细胞的脂肪生成。这种现象可能是由RXR γ的补偿性增加引起的。此外，我们发现KLF 8 介导了RXR α的积极作用。siRNA对KLF 8 的敲低减弱了RXR α 对脂肪细胞分化的影响。重要的是，当RXR α过表达时，KLF 8的启动子活性增强。总之，我们的数据表明RXR α 通过靶向KLF 8促进山羊肌肉内前脂肪细胞的分化，但它可以被RXR γ取代。这些结果为改进山羊肉的质量提供了新的见解。