双氢睾酮对HaCaT细胞SREBP-1c表达的影响

目的 探讨双氢睾酮（DHT）在HaCaT细胞固醇调控元件结合蛋白-1c（SREBP-1c）表达中的作用。 方法 体外培养HaCaT细胞，分为4组，对照组不加任何刺激因素，DHT组分别加入3种不同浓度的DHT，LY294002 + DHT组在加入50 μmol/L PI3K抑制剂（LY294002）预处理40 min后加入100 nmol/L DHT，PD98059 + DHT组即在加入50 μmol/L MEK抑制剂（PD98059）预处理40 min后加入100 nmol/L DHT。用实时定量PCR和Western印迹法检测DHT对HaCaT细胞SREBP-1c mRNA和蛋白表达的影响。Western印迹法检测DHT作用于HaCaT细胞后蛋白激酶B（AKT）、胞外信号调控激酶（ERK）、p38丝裂原活化蛋白激酶（p38 MAPK）、c-Jun氨基末端激酶（JNK）的磷酸化情况。 结果 DHT可呈浓度依赖性上调HaCaT细胞SREBP-1c mRNA和蛋白的表达，并诱导AKT、ERK的磷酸化，但对p38、JNK的磷酸化无明显激活作用。LY294002预处理后HaCaT细胞SREBP-1c mRNA的表达较单纯DHT组明显降低（t = 9.406，P < 0.05）；SREBP-1蛋白水平降为0.7113 ± 0.0313，与单纯DHT组2.2577 ± 0.0601比较，差异有统计学意义（t = 39.498，P < 0.05）。而PD98059预处理后，SREBP-1c mRNA和蛋白的表达与单纯DHT组比较，差异均无统计学意义（P > 0.05）。结论 DHT可诱导HaCaT细胞SREBP-1c mRNA和蛋白的表达。

Effects of dihydrotestosterone on the expression of SREBP-1c in human HaCaT keratinocytes

Objective To evaluate the effects of dihydrotestosterone （DHT） on the expression of sterol regulatory element-binding protein-1c （SREBP-1c） in human HaCaT keratinocytes. Methods HaCaT cells were cultured in vitro and classified into 4 groups, i.e., control group receiving no treatment, DHT group treated with 3 different concentrations （10, 100, 1000 nmol/L） of DHT, LY294002 plus DHT group treated with DHT of 100 nmol/L after 40-minute pretreatment with the PI3K inhibitor LY294002 of 50 μmol/L，PD98059 plus DHT group treated with DHT of 100 nmol/L after 40-minute pretreatment with the MEK inhibitor PD98059 of 50 μmol/L. After another 24-hour culture, real time PCR and Western blot were carried out to detect the expression of SREBP-1c mRNA and protein in HaCaT cells, respectively. Western blot was also performed to determine the phosphorylation levels of protein kinase B（AKT）, extracellular signal-regulated kinase（ERK）, p38 mitogen-activated protein kinase and c-Jun N-terminal kinase （JNK） in the HaCaT cells. Results DHT could enhance the expression of SREBP-1c mRNA and protein in HaCaT cells in a concentration-dependent manner, and induce the phosphorylation of AKT and ERK, but not that of P38 or JNK. The expressions of SREBP-1c mRNA and protein were significantly decreased in HaCaT cells treated with LY294002 plus DHT （7.4780 ± 1.2638 vs. 21.6170 ± 2.2759, t = 9.406, P < 0.05; 0.7113 + 0.0313 vs. 2.2577 + 0.0601, t = 39.498, P < 0.05）, but experienced no statistical changes in those treated with PD98059 and DHT（both P > 0.05）, compared with those treated with DHT only. Conclusion DHT can induce the expression of SREBP-1c mRNA and protein in HaCaT cells, likely via the PI3K/AKT signaling pathway.