柴胡皂苷D调控CaMKKβ/AMPK信号通路介导ICCs细胞自噬的机制

Mechanism of Saikosaponin D Mediating Autophagy in ICCs by Regulating CaMKKβ/AMPK Signaling Pathway

目的探讨柴胡皂苷D调控CaMKKβ/AMPK信号通路,在功能性消化不良中对胃肠道Cajal间质细胞(Interstitial cells of Cajal,ICCs)细胞自噬的作用及机制。方法分离大鼠原代ICCs细胞,谷氨酸刺激构建ICCs自噬模型,免疫荧光检测Ca2+水平。将原代ICCs细胞分为对照组、模型组、模型+柴胡皂苷D组、模型+CaMKKβ抑制剂组、模型+柴胡皂苷D+CaMKKβ抑制剂组。透射电镜观察自噬体超微结构,ELISA检测Ghrelin和SP的水平,免疫荧光检测Ca2+和LC-3Ⅱ的表达,Western blot检测LC-3Ⅱ/Ⅰ、CaMKKβ、p-AMPK、Drp1、MFN2、IP3R和RyR的蛋白表达水平。结果谷氨酸诱导的模型组ICCs中LC-3Ⅱ荧光表达增强。柴胡皂苷D干预可降低Ca2+浓度,降低CaMKKβ、AMPK和MFN2水平(P<0.01),增加LC-3Ⅱ/Ⅰ、IP3R、RyR、Drp1、Ghrelin和SP水平(P<0.01)。柴胡皂苷D联合CaMKKβ抑制剂STO-609干预后效果更显著。结论柴胡皂苷D可通过CaMKKβ/AMPK信号通路介导Ca2+外流,影响ICCs细胞过度自噬及胃肠动力相关因子的表达。

Objectives To explore the effect and mechanism of saikosaponin D on cellular autophagy of ICCs by regulating the CaMKKβ/AMPK signaling pathway.Methods Rat primary ICCs cells were isolated and stimulated with glutamate to construct an autophagy model.The Ca2+level was detected by immunofluorescence.Primary ICCs cells were divided into control group,model group,model+saikosaponin D group,model+CaMKKβinhibitor group,and model+saikosaponin D+CaMKKβinhibitor group.The ultrastructure of autophagosomes was observed by transmission electron microscopy.The levels of Ghrelin and SP were detected by ELISA.The expressions of Ca2+and LC-3Ⅱwere detected by immunofluorescence.The protein expression levels of LC-3Ⅱ/Ⅰ、CaMKKβ,p-AMPK,Drp1,MFN2,IP3R and RyR were detected by Western blot.Results The fluorescence expression of LC-3Ⅱwas enhanced.Saikosaponin D reduced the levels of CaMKKβ,AMPK and MFN2(P<0.01),and increased the levels of LC-3Ⅱ/Ⅰ、IP3R,RyR,Drp1,Ghrelin and SP(P<0.01).The effect of Saikosaponin D combined with CaMKKβinhibitor STO-609 was more significant.Conclusion Saikosaponin D can mediate Ca2+outflow through the CaMKKβ/AMPK signaling pathway,and affect the expression of excessive autophagy and gastrointestinal motility-related factors in ICCs cells.