Figure 3.

Effect of undecane on cyclic adenosine monophosphate (cAMP)-mediated inflammatory signaling pathway in HaCaT cells. (A) After pretreatment (1 h) of vehicle (DMSO) or undecane (1, 5 and 10 μM), the cells were incubated with TNF-α/IFN-γ (10 ng/mL each) for 1 h and nuclear factor kappaB (NF-κB) transcriptional activity was measured in nuclear extraction of each group. (B) HaCaT cells were incubated with undecane (5 μM) for various times and the effect of undecane on intracellular cAMP levels was determined. Western blot was performed to assess the protein levels of (C, D) protein kinase A (PKA), (E) p-CREB, cAMP-response element-binding protein (CREB), p-p38 and p38 in HaCaT cells. (C) HaCaT cells were incubated with TNF-α/IFN-γ (10 ng/mL each) for various times and PKA level was measured. (D) In a similar manner, TNF-α/IFN-γ-stimulated HaCaT cells were cultured with vehicle or undecane for various times and PKA level was determined. (E) After pretreatment (1 h) of vehicle or undecane (5 μM), the cells were incubated with TNF-α/IFN-γ for 1 h and phosphorylation of CREB and p38 was measured. All the protein expression data were normalized against glyceraldehyde 3-phosphate dehydrogenase (GAPDH) level. The data were expressed as the mean ± SEM (n = 3). Significant differences between groups are indicated by asterisks; ns, not significant (p > 0.05); * p < 0.05; ** p < 0.01; *** p < 0.001.