Roles of protein kinase B and mitogen-activated protein kinase pathways in the protection by nicotinic acid against ultraviolet B-induced damage in keratinocytes
10.3760/cma.j.issn.0412-4030.2012.11.016
- VernacularTitle:蛋白激酶B和丝裂原活化蛋白激酶在烟酸保护的HaCaT细胞抵抗中波紫外线损伤中的作用
- Author:
Fuquan LIN
;
Wen XU
;
Cuiping GUAN
;
Miaoni ZHOU
;
Weisong HONG
;
Dongyin LIU
;
Aie XU
- Publication Type:Journal Article
- Keywords:
Niacin;
Keratinocytes;
Ultraviolet rays;
Mitogen-activated protein kinase;
Proto-oncogene proteins c-akt
- From:
Chinese Journal of Dermatology
2012;(11):806-810
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the intracellular signal transduction pathways involved in the protective effect of nicotinic acid against ultraviolet B(UVB)-induced damage in human skin keratinocytes.Methods Cultured human keratinocyte HaCaT cells were divided into several groups to be treated with nicotinic acid,UVB irradiation,LY294002(an inhibitor of Akt),U0126(an inhibitor of extracellular signal-regulated kinase(ERK)1/2),SB203580(an inhibitor of P38)alone or in combination for different durations.Then,Western blot was performed to quantify the phosphorylation levels of the protein kinase B(Akt)/MAPK pathwayassociated proteins including Akt,P38,JNK and ERK1/2,MTT assay to evaluate the activity of HaCaT cells,enzyme-linked immunosorbent assay to determine the levels of endothelin-1(ET-1)and basic fibroblast growth factor(bFGF)in the culture supernatant of HaCaT cells,and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL)to evaluate the apoptosis in HaCaT cells.Results As Western blot showed,phosphorylated Akt,P38,JNK and ERK1/2 were markedly activated within 60 minutes after pretreatment with nicotinic acid and irradiation with UVB(all P ＜ 0.01),and the activation was more significant for phosphorylated Akt,P38,and ERK1/2 within 2 hours(all P ＜ 0.01).Nicotinic acid effectively suppressed the UVB-induced cell death and apoptosis in HaCaT cells.The levels of supernatant ET-1 and bFGF were significantly decreased in HaCaT cells treated with the above 3 inhibitors followed by UVB irradiation than in those treated with the inhibitors alone(all P ＜ 0.05),and nicotinic acid pretreatment only reversed the decrease in supernatant bFGF in HaCaT cells treated with SB203580 followed by UVB irradiation.Conclusion The Akt signaling pathway may play a regulatory role in the protection by nicotinic acid against UVB-induced damage in HaCaT cells.
