Abstract:

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.

Key words: signal