凋亡信号调节激酶1通过c-Jun氨基末端激酶通路调控高糖诱导的视网膜神经节细胞损伤

ASK1 mediates high glucose-induced retinal ganglion cell injury via JNK pathway

目的研究细胞凋亡信号调节激酶1(apoptosis signal-regulating kinase1,ASK1)对高糖诱导的视网膜神经节细胞(retinal ganglion cell,RGC)损伤的保护作用及其可能的机制。方法建立大鼠RGC细胞的分离培养和体外高糖(50 mmol/L葡萄糖)损伤模型。转染ASK1 siRNA沉默ASK1的表达。实时荧光定量PCR(qRT-PCR)检测ASK1 mRNA表达水平;Western blot检测ASK1、JNK蛋白表达量和c-Jun氨基末端激酶(c-Jun N-terminal kinase,JNK)磷酸化水平;MTT和CCK-8方法、Ki67染色分别检测RGC生长活力和增殖情况;Annexin-V FITC/PI方法和TUNEL检测RGC凋亡情况;试剂盒方法检测Caspase-3活性。结果 RGC高糖环境下培养4d,细胞生长活力降低明显(P<0.05);ASK1表达水平在高糖损伤的RGC中明显上升(P<0.05);ASK1 siRNA的转染实验结果显示:ASK1的表达水平明显下降(P<0.05),说明沉默表达实验成功;ASK1表达被抑制后RGC的生长活力(P<0.05)和增殖能力(P<0.05)明显上升,RGC的凋亡(P<0.01)和Caspase-3的活力(P<0.01)明显降低。沉默ASK1的表达有效地降低JNK蛋白的磷酸化水平。结论抑制ASK1的表达对RGC的高糖损伤有保护作用,其机制可能与抑制JNK通路有关。

Objective To investigate the protective effect of apoptosis signal-regulating kinase 1 （ASK1） on high glucose-induced injury in retinal ganglion cells （RGCs） and its possible mechanism. Methods Rat RGCs were isolated, cultured and subjected to high glucose （50 mmol/L） environment to establish an RGCs injury model. Gene silencing of ASK1 was performed by transfection of ASK1 siRNA into RGCs. The mRNA expression of ASK1 was measured by quantitative real-time PCR （qRT-PCR）. The protein expression levels of ASK1, total JNK and phosphorylated JNK were detected by Western blotting. Cell growth and viability, and cell proliferation of RGCs were measured by MIT and CCK-8 assays and Ki67 staining, respectively. The apoptosis of RGCs was detected by Annexin-V FITC/PI and TUNEL staining. Caspase-3 activity was measured by fluorescent assay kit. Results Cell growth and viability of RGCs was significantly decreased after treated with high glucose for 4 d （ P 〈 0. 05 ）. qRT-PCR measurement showed that ASK1 was significantly up regulated in RGCs treated with high glucose （ P 〈 0. 05 ）. The expression of ASK1 was significantly down regulated in the ASK1 siRNA-transfected RGCs （P 〈 0.05 ）, suggesting a successful silencing of ASK1. The silencing of ASK1 remarkably increased cell growth and viability （ P 〈 0. 05 ） and proliferation （P 〈 0. 05 ）, as well as significantly suppressed the apoptosis （P 〈 0. 01 ） and Caspase-3 activity （P 〈0. 01 ）. Furthermore, inhibition of ASK1 effectively restricted the phosphorylation of JNK. Conclusion ASK1 inhibition has a protective effect on high glucose-induced injury of retinal ganglion cells, which is partly modulated by JNK pathway.