目的:观察硫化氢(H2S)对PC12细胞淀粉样前体蛋白(APP)代谢途径的影响,探讨可能的细胞信号机制。方法:用不同浓度硫氢化钠(NaHS,50、100和200μmol·L-1)作用PC12细胞1和18h,Westernblotting法检测APP、C99、C83、磷脂酰肌醇-3激酶/丝氨酸苏氨酸蛋白激酶(PI3-K/Akt)及丝裂原活化蛋白激酶/细胞外信号调节激酶1/2(MAPK/ERK1/2)信号通路相关蛋白的水平;ELISA检测细胞培养液中Aβ42的水平。50μmol·L-1 NaHS作用于PC12细胞前30min加入PI3-K抑制剂LY294002(25和50μmol·L-1)或MAPK激酶(MEK)抑制剂PD98059(25和50μmol·L-1),重复上述检测。各种检测实验均设正常对照组。结果:与正常对照组比较,50μmol·L-1 NaHS组C99及Aβ42水平降低(P〈0.05),C83的表达提高(P〈0.05),Akt及ERK1/2的磷酸化增加(P〈0.05),而LY294002可抑制NaHS的上述作用,但PD98059不具有与LY294002类似的作用。结论:H2S能使APP的代谢向非淀粉样途径转变,其机制可能涉及PI3-K/Akt信号通路。
Objective To observe the effect of hydrogen sulfide(H2S) on the processing of the amyloid precursor protein(APP) and explore the possible cellular signaling mechanisms in PC12 cells.Methods The PC12 cells were treated with 50,100 and 200 μmol·L-1 sodium hydrosulfide(NaHS) for 1 and 18 h.Western blotting method was used to detect the protein levels of C99,C83,APP,Akt,pAkt,ERK1/2 and pERK1/2.The level of Aβ42 in cellular culture medium was analyzed by ELISA.The specific PI3-K inhibitor,LY294002(25 and 50 μmol·L-1),or the specific MAPK kinase(MEK) inhibitor,PD98059(25 and 50 μmol·L-1),were added to the PC12 cells 30 min prior to 50 μmol·L-1 NaHS treatment.Then the above tests were repeated.At the same time normal control group was set up.Results Compared with normal control group,the expressions of C99 and Aβ42 were decreased(P〈0.05),the expressions of C83 and pAkt and the phosphorylation of ERK1/2 were increased(P〈0.05)in 50 μmol·L-1 NaHS group.LY294002 but not PD98059 inhibited the above effects of NaHS.Conclusion H2S makes APP processing change from the non-amyloidogenic pathway to the amyloidogenic pathway,which may involve PI3-K/Akt signaling pathway.