葡萄糖调节蛋白GRP78在小梁网细胞中的表达及临床意义

Expression and clinical significance of GRP78 in human trabecular meshwork cells

目的检测葡萄糖调节蛋白78(GRP78)在体外培养的正常人小梁网细胞(NTM)及原发性开角型青光眼(POAG)患者小梁网细胞(GTM)中蛋白及m RNA表达差异及临床意义。方法将体外培养的NTM及GTM细胞分为衣霉素(Tm)组、十字孢碱(STS)组及对照组,采用Real-time PCR、Western blot方法检测药物处理6、24 h后小梁网细胞中GRP78 m RNA及蛋白表达。结果原代培养的GTM细胞中GRP78表达水平明显低于NTM细胞,差异有统计学意义(P<0.05)。Tm可增加NTM、GTM细胞中GRP78的表达,但后者的增高水平明显低于前者,差异有统计学意义(P<0.05)。GTM细胞对STS的反应大于NTM细胞。结论 POAG患者小梁网细胞对内质网应激反应能力低下,GRP78表达明显下调,对损伤性刺激的敏感性增强,提示GRP78蛋白可能在内质网应激诱导产生的小梁细胞凋亡中起保护作用。

Objective To detect protein and m RNA expression differences of GRP78 in human trabecular meshwork cells of normal eyes(NTM) and POAG patients(GTM) in vitro. Methods Human trabecular meshwork cells from NTM and GTM in vitro were divided into 3 groups: Tunicamycin(Tm) group, Staurosporine(STS) group and control group.Real-time RT-PCR and Western blot were used to detect the expression of m RNA and protein of GRP78 in trabecular meshwork cells after 6, 24 h treatment. Results The expression of GRP78 in primary culture GTM cells was significantly lower than that in NTM cells, with statistically significant difference(P < 0.05). Tm could increase the expression of GRP78 in NTM and GTM cells, the expression in GTM cells was lower than that in NTM cells, with statistically significant difference(P < 0.05). The response of GTM cells for STS was bigger than NTM cells. Conclusion GTMs showed insensitivity reactions when stimulated with inducer of endoplasmic reticulum stress, reduce the expression of GRP78,lead to the increased sensitivity of GTMs to damage stimulus. GRP78 may play a cytoprotective role in the apoptosis in trabecular meshwork cells caused by endoplasmic reticulum stress.