敲低低密度脂蛋白受体相关蛋白1抑制C3H10T1/2多潜能干细胞定向成脂

Knock Down of Low Density Lipoprotein Receptor-related Protein 1(Lrp1) by RNAi Inhibits The Commitment of C3H10T1/2 Pluripotent Stem Cells to Preadipocyte

C3H10T1/2多潜能干细胞成脂过程分为定向和分化两个阶段,骨形成蛋白4(BMP4)可以诱导其定向成前脂肪细胞.已有的研究表明,脂肪组织特异性敲除低密度脂蛋白受体相关蛋白1(Lrp1)的小鼠体重减轻,脂肪组织含量减少,揭示此基因对成脂具有重要作用.然而,目前尚不清楚Lrp1是否在成脂定向过程中发挥作用.采用小干扰RNA技术(RNAi),在体外水平研究低密度脂蛋白Lrp1对C3H10T1/2多潜能干细胞成脂定向的作用.分别在C3H10T1/2成脂的定向期和脂滴成熟期敲低Lrp1,通过显微镜下观察、油红O染色、Western blotting等实验证实,定向期而非脂滴成熟期敲低Lrp1显著抑制C3H10T1/2多潜能干细胞成脂.BMP4通过激活下游Smad1/5/8信号通路发挥作用,而敲低Lrp1显著抑制BMP4诱导的Smad1/5/8磷酸化.这些结果说明:敲低Lrp1通过下调Smad信号通路,抑制BMP4诱导的C3H10T1/2多潜能干细胞成脂定向.

The adipocyte development process of C3H10T1/2 pluripotent stem cells includes two stages： the commitment stage and the differentiation stage. There are evidences that BMP4 commits C3H10T1/2 cells into preadipocytes. Previous studies have shown that mice lacking adipocyte Lrpl （adLrpl-/-） displays reduced body weight and smaller fat stores which highlights the important role of Lrpl in adipogenesis. However, little is known about the role of Lrpl in preadipocyte commitment. RNAi was used to study the effect of low density lipoprotein receptor-related protein 1 （Lrp 1） on commitment of C3H 10T 1/2 to preadipocyte. Through microscopic examination, Oil red O staining, Western blotting, it is demonstrated that Lrpl RNAi inhibits C3H10T1/2 adipogenesis in commitment stage, rather than in lipid maturation period. BMP4 signals through Smadl/5/8 and Lrpl RNAi significantly suppresses the BMP4-triggered phosphorylation of Smadl/5/8. These data suggest that Lrpl RNAi has inhibitory effects on the BMP4-induced of C3H10T1/2 preadipocyte commitment via down-regulating Smad signaling.