原花青素B2通过XBP1-s干预高脂环境诱导RPE细胞氧化应激机制研究

Dietary supplements have been regarded as efficient strategy to protect retinal pigment epithelium(RPE) from high fat environment induced oxidative stress and inflammation. However, the mechanisms have not been elucidated. Our previous research revealed that procyanidin B2 attenuates lipidosis induced oxidative stress, and inhibits apoptosis in RPE. In addition, Procyanidin B2 upregulates unfolded protein response (UPR) molecular chaperone. These informations indicate that the inhibition on oxidative stress and inflammation by Procyanidin B2 is associated to UPR. Therefore, we’ll investigate the role of UPR in the inhibition on RPE oxidative stress and inflammation by Procyanidin B2 using in vitro and in vivo high fat environment model. The effect of Procyanidin B2 on XBP-1s, the key regulator of UPR, will be studied. Then the regulation of UPR by Procyanidin B2 will be investigated using XBP-1s overexpression and knockdown technology. Lastly, the effect of Procyanidin B2 on inflammation pathway down stream of UPR will be analyzed. The mechanism by which Procyanidin B2 regulates UPR via XBP-1s to inhibit RPE inflammation will be explored. Our research will help to reveal the inhibiting mechanism of high fat environment induced RPE oxidative stress and inflammation by Procyanidin B2, and show new idea of preventing dyslipidemia induced visual impairment.

氧化应激引发视网膜色素上皮细胞(RPE)炎症反应是视觉功能损伤主要因素之一，抗氧化剂抑制高脂环境诱导RPE氧化应激及炎症反应的机制鲜有报道。课题组前期研究发现原花青素B2抑制脂质沉积诱导RPE氧化损伤，上调未折叠蛋白反应(UPR)关键分子伴侣表达，提示原花青素B2对RPE氧化应激的抑制作用与UPR相关。以此为基础，课题组拟在高脂环境细胞模型和动物模型中，采用特异性抑制剂和基因沉默技术，研究UPR在原花青素B2抑制氧化应激引发RPE细胞炎症反应中的作用；研究原花青素B2对UPR通路关键调控分子XBP1-s的影响，探讨原花青素B2通过XBP1-s对UPR的调控作用以及对UPR下游炎症通路的影响，阐明原花青素B2通过XBP1-s调节UPR通路，从而抑制RPE炎症反应的分子机制。课题完成将为原花青素抑制高脂环境诱导RPE氧化应激提供理论依据，为通过膳食营养缓解脂代谢紊乱相关视觉功能损伤提供新思路。

糖代谢、脂代谢紊乱会引起机体氧化应激，导致视网膜细胞炎症反应，是视觉功能损伤主要因素之一。目前尚无有效的治疗药物，通过膳食补充抗氧化剂是预防、延缓视网膜组织氧化损伤的重要手段，但其抑制高糖、高脂环境诱导视网膜细胞炎症反应的作用机制尚不清晰。课题组前期研究发现原花青素抑制脂质沉积诱导视网膜色素上皮细胞氧化损伤，上调未折叠蛋白反应(UPR)关键分子伴侣表达，提示原花青素对视网膜细胞氧化应激的抑制作用与UPR相关。以此为基础，课题组构建了高糖、高脂环境诱导视网膜细胞炎症反应动物模型和细胞模型，研究原花青素对高糖、高脂环境下视网膜细胞氧化应激损伤及炎症因子表达的影响。研究结果明确了原花青素具有降低高糖、高脂环境诱导视网膜组织炎症因子过表达，抑制细胞损伤的作用，并且明确了原花青素调控内质网应激反应（ER stress）与抑制炎症因子表达之间的相关性。揭示了原花青素通过上调 UPR 关键分子伴侣Bip的表达，抑制XBP-1剪切活化，从而抑制NLRP3炎症小体活化，降低炎症因子表达水平的分子机制。此外，明确了原花青素激活Nrf2抗氧化通路，提高抗氧化酶表达水平，从而抑制高糖、高脂环境下视网膜细胞中促炎症因子表达水平。研究成果为通过膳食营养预防、缓解高血糖、高血脂相关视觉功能损伤提供新思路。研究成果发表在Journal of Functional Foods等食品科学领域优秀期刊，现共发表SCI论文3篇。