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

Abstract

Obective 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,DIIT 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: Dihydrotestosterone; HaCaT cells; Sterol regulatory element binding protein 1; Signal transduction