ABSTRACT
Objective To evaluate the effects of urotensin Ⅱ on cell proliferation of and α-smooth muscle actin (α-SMA) expression in normal human dermal fibroblasts (NFs),and to explore their regulatory mechanisms.Methods NFs were isolated from foreskin tissues and subjected to primary culture in vitro.Reverse transcription PCR and Western blot analysis were performed to measure the mRNA and protein expression of urotensin Ⅱ and its receptor,respectively.Cell counting kit-8 (CCK-8) assay was conducted to estimate the proliferation of NFs,which were treated with urotensin Ⅱ at different concentrations of 0,10-10,10-9,10-8,10-7 and 10-6 mol/L for 0,6,12,24 and 48 hours separately,and then the optimal concentration and duration of urotensin Ⅱ exposure were selected to be 10-8 mol/L and 24 hours respectively.Some cultured NFs were divided into 5 groups:control group receiving no treatment,U Ⅱ group treated with 10-8 mol/L urotensin Ⅱ,U Ⅱ + nicardipine group treated with 10-8 mol/L urotensin Ⅱ and the calcium channel blocker nicardipine at the concentration of 10-5 mol/L,U Ⅱ + PD98059 group treated with 10-8 mol/L urotensin Ⅱ and the mitogen activated protein kinase (MAPK)inhibitor PD98059 at the concen-tration of 10-5 mol/L,and U Ⅱ + cyclosporine group treated with 10-8 mol/L urotensin Ⅱ and the calcium-dependent protein kinase (CaM PK) inhibitor cyclosporine at the concentration of 10-5 mol/L.After 24-hour treatment,CCK-8 assay was conducted to evaluate the proliferation of NFs in the above groups,real-time fluorescence-based quantitative PCR and Western blot analysis were performed to determine the mRNA and protein expression of α-SMA respectively.Results Urotensin Ⅱ receptor was expressed in NFs,but urotensin Ⅱ was not.The proliferative activity of NFs significantly differed among the control group,U Ⅱ group,U Ⅱ + nicardipine group,U Ⅱ + PD98059 group and U Ⅱ + cyclosporine group (the mean absorbance value at 405 nm:1.036 ± 0.046,1.405 ± 0.158,1.121 ± 0.109,1.192 ± 0.089 and 1.141 ± 0.056,respectively;F =9.587,P ＜ 0.01),and the U Ⅱ group showed significantly higher proliferative activity of NFs compared with the control group,U Ⅱ + nicardipine group,U Ⅱ + PD98059 group and U Ⅱ + cyclosporine group (q =8.263,6.355,4.774 and 5.912,respectively,all P ＜ 0.05).There were significant differences in the mRNA and protein expression of α-SMA among the 5 groups (F =6.351,7.045,both P ＜ 0.01),and the mRNA and protein expression of α-SMA was significantly higher in the U Ⅱ group than in the other 4 groups (all P ＜ 0.05).Conclusion Urotensin Ⅱ may induce the proliferation of and α-SMA expression in NFs through calcium channels,MAPK and CaM PK pathways.
ABSTRACT
Objective To investigate the relationship of PI3K/Akt signaling pathway with the activation of hepatic stellate cells (HSC) and its role in radiation-induced hepatic fibrosis.Methods HSC was treated with 6 MV X-ray irradiation (IR) together with the inhibitor of PI3K/Akt signaling pathway.The cells were divided into inhibitor group,10 Gy IR group,10 Gy + inhibitor group,20 Gy IR group,an 20 Gy + inhibitor group and blank control group.Then cell apoptosis rate was detected,the expression of transforming growth factor β1 (TGF-β1) in cell supernatant and the mRNA expressions of α-smooth muscle actin (α-SMA) and phosphorylation protein kinase B (p-Akt) were measured.Results Compared with the control group,the apoptosis rate of 10 and 20 Gy IR group increased with irradiation dose (t =8.43,11.63,P ＜0.05) but they were reduced by the inhibitor of PI3K/Akt (t =8.09,4.88,P ＜0.05).The expressions of TGF-β1,α-SMA,and p-Akt also increased with irradiation dose (t =6.91,7.80,9.28,P＜0.05) but they were declined by this inhibitor for both 10 Gy IR (t =6.17,15.11,10.34,P＜0.05) and 20 Gy IR (t =10.04,6.85,23.84,P＜0.05).Conclusions X-ray irradiation could activate HSC through PI3K/Akt signaling pathway,which may further result in hepatic fibrosis.