RGC-32基因在睑板腺功能障碍发病中的作用和机制研究

Meibomian gland dysfunction (MGD) is the leading cause of dry eye disease, which affects the health and well-being of patients worldwide. Clarifying the mechanism of MGD is particularly important for developing safe and effective therapeutics. Recent studies have shown that RGC-32 gene and oxidative stress were associated with the onset of MGD, however, the specific mechanisms remained unknown. In our previous work we found that oxidative stress induced decreased expression levels of Cyclin D1、Cyclin B1, inhibited cell proliferation, and stimulated apoptosis as shown by the increased apoptotic cells and decreased mitochondria membrane potential in Meibomian gland epithelial cells. Also, oxidative stress caused a down regulation of RGC-32 gene, while activated the JNK MAPK and ERK MAPK signaling pathways. Our preliminary results suggested RGC-32 gene, stimulated by oxidative stress, may play an active part in the pathogenesis of MGD as a cell cycle regulator, which has not been reported before. The current study aims to investigate how RGC-32 contributes to cell cycle regulation and cellular growth, to identify whether JNK MAPK and ERK MAPK signaling pathways are involved in oxidative stress induced RGC-32 down-regulation, and to explore the potential role of RGC-32 in Meibomian gland epithelial cell response to oxidative stress, in order to expand our understanding about the pathogenesis of MGD and to provide new insight into therapeutic potentials for this disease.

睑板腺功能障碍(MGD)是干眼症的主要病因,中老年人群患病率高且生活质量受到显著影响。研究表明RGC-32基因和氧化应激均与MGD发病存在联系,但其具体分子生物学机制未明。我们在前期工作中发现：氧化应激可引起睑板腺上皮细胞RGC-32基因表达下调，细胞周期蛋白CyclinB1、CyclinD1表达减少，细胞增殖能力降低；细胞凋亡率升高；同时伴细胞内JNK MAPK、ERK MAPK信号通路的活化。根据以上研究结果，本课题组首次提出RGC-32基因可能受到氧化应激的影响表达减少，进而影响细胞周期循环和细胞增殖过程，参与MGD的发生。我们拟进一步研究RGC-32基因在睑板腺上皮细胞周期循环和细胞增殖过程中的调控作用，了解氧化应激是否通过JNK MAPK和ERK MAPK信号通路影响RGC-32表达，明确RGC-32基因在细胞氧化损伤中的作用机制，以期为临床上治疗MGD提供新的理论依据和实验基础

氧化应激是引起睑板腺细胞损伤、诱发睑板腺功能障碍（Meibomian gland dysfunction，MGD）的一个重要因素。MGD患者的RGC-32基因表达水平显著低于正常人群，但该基因的在MGD发病中的具体作用及其机制未明。我们发现，敲除RGC-32基因后，人睑板腺上皮细胞中cyclin D1表达量减少，细胞周期停滞，失去原有增殖能力。体外培养的人睑板腺上皮细胞受到过氧化氢刺激后，RGC-32基因表达下调，细胞周期蛋白cyclin B1、cyclin D1表达减少，细胞凋亡率增加，同时伴有JNK/ERK MAPKs信号分子激活。JNK/ERK MAPKs信号通路抑制剂可阻断过氧化氢造成的上述影响，上调氧化应激状态下人睑板腺上皮细胞RGC-32基因和蛋白表达水平，提高细胞增殖活性。以上研究结果表明，RGC-32基因通过影响细胞周期蛋白表达，对人睑板腺上皮细胞周期活动起正性调节作用；氧化应激通过JNK/ERK MAPKs信号通路，影响RGC-32表达，干扰细胞周期，破坏细胞增殖能力。“MAPKs信号通路-RGC-32基因-细胞周期蛋白”可能是造成睑板腺氧化损伤、导致MGD的潜在分子生物学机制。