敲低小鼠中脑神经元多巴胺D2受体使其生脂基因表达上凋

Knockdown of dopamine receptor D2 upregulates the expression of adiogenic genes in mouse primary mesencephalic neurons

目的研究小鼠中脑神经细胞多巴胺D2受体(DRD2)对神经元生脂基因的调节作用。方法构建针对DRD2短发夹RNA(shRNA)的慢病毒载体,特异性下调小鼠原代中脑神经元的DRD2表达;神经元分为阴性病毒对照组和DRD2-shRNA病毒感染组,进行高通量转录组测序,分析两组差异基因并以共表达网络筛选核心基因;实时荧光定量PCR及Western blot法验证该差异基因表达并检测神经元脂肪酸含量变化。结果成功培养小鼠中脑神经元并下调DRD2;高通量转录组测序发现中脑神经细胞DRD2下调对多个生脂基因有调节作用,主要包括δ(14)-固醇还原酶、乙酰辅酶A合成酶、胰岛素诱导基因1蛋白、硬脂酰辅酶A去饱和酶等,其中硬脂酰辅酶A去饱和酶1(SCD1)上调最显著(上调4倍),并经实时定量PCR和Western blot结果得到验证。同时脂肪酸含量检测发现与SCD1关系密切的游离脂肪酸在DRD2下调组显著增加。结论下调小鼠中脑神经元DRD2可以显著上调SCD1的表达,SCD1上调可以加速饱和脂肪酸向单不饱和脂肪酸转化,防止脂毒性对细胞的损伤。

Objective To study the effects of dopamine receptor 132 （DRD2） on the adipegenesis genes in meuse primary mesencephalic neurons. Methods The lentiviral vectors which expressed specific shRNA targeting DRD2 were constructed to decrease DRD2 expression in mouse primary mesencephalic neurons. High throughput sequencing （HTS） analysis was used to investigate gene expression changes between the DRD2 knock-down group and the negative control group. Real-time quantitative PCR （qRT-PCR） and Western blot analysis were applied to verify the differently expressed genes. Fatty acids were measured by fatty acid detection kit. Results DRD2 expression was effectively down-regulated in mouse primary mesencephalic neurons by lentiviral vectors. HTS revealed adipogenesis genes were significantly up-regulated after DRD2 down-regulation, mainly including delta （14）-sterol reductase, acetyl-coenzyme A synthetase, insulin-induced gene 1 protein and especially stearoyl-coenzyme A desaturase 1 （SCD1, 4-fold upregulated）. The qRT-PCR and Western blot analysis verified that SCDI was upregulated 2.6 folds and 2 folds respectively by lentiviral DRD2-shRNA vectors. Moreover, the SCD1- related free fatty acids were significantly more increased than the negative control group. Conclusion DRD2 in primary mesencephalic neurons had a significant regulative effect on the adipogenesis genes. The up-regulation of SCD1 can accelerate the conversion of saturated fatty acids to menounsaturated fatty acids and prevent the damage of lipid toxicity to cells.