氧化应激是肝病、肾病等发病的共同病理生理基础，Keapl-Nrf2-ARE通路是迄今发现的最重要的内源性抗氧化应激通路。因此，筛选Keap1-Nrf2-ARE通路的高效激动剂成为海洋抗氧化药物的研究热点。课题组研究发现海洋高F值寡肽具有显著的抗氧化和保肝护肝等生理活性，可促进Nrf2蛋白的表达，并制备了Keap1-Nrf2-ARE通路肽类激动剂IELVW和IIGLVP。基于此，本课题以Keap1-Nrf2-ARE通路抗氧化药物筛选模型为导向，从海洋高F值寡肽中制备60～80种肽类激动剂，其中高活性激动剂3～5个，并利用HL7702细胞和小鼠肝损伤模型研究肽类激动剂体内外抗氧化应激的作用机制，阐明肽类激动剂激动Keap1-Nrf2-ARE通路的作用机制及其构效关系，剖析肽类激动剂与高F值寡肽生理活性之间的内在联系。本项目的研究将为海洋抗氧化新药研发提供候选药物，促进海洋生物资源的高值化利用。

Oxidative stress (OS), initiated by superfluous reactive oxygen species (ROS), is the collective pathophysiological mechanism of many hepatopathies, nephropathy, cardiovascular and cerebrovascular diseases, and diabetes mellitus, which plays a significant role in the form and development of diseases on OS. Nuclear factor erythroid-2 related factor 2 (Nrf2) is an important nuclear transcription factor which protects cells against OS injury. Upon exposure to ROS or electrophilic stress, Nrf2 can separate from Keap1 and translocate into the nucleus, and then bind to the antioxidant response element (ARE), regulating the expression of antioxidant and phase II detoxifying enzymes which aim at the detoxification and elimination of harmful exogenous chemicals. Therefore, the Keap1-Nrf2-ARE pathway is extremely important in the progression of prevention and therapy of many diseases related to OS and has been implicated as a new therapeutic target for screening antioxidant drugs.. Oligopeptide is usually composed of 3 to 9 amino acids. High Fischer ratio oligopeptide is one kind of peptide mixture with a molar ratio of branched-chain amino acids (Leu, Ile and Val) to aromatic amino acids (Phe, Trp and Tyr) higher than 20. At present, high Fischer ratio oligopeptides have been reported to have multi-physiological functions, including protecting liver, antioxidation, fatigue resistance and anti-aging. Our previous research indicated that high Fischer ratio oligopeptide from skipjack tuna (Katsuwonus pelamis) could increase the expression level of Nrf2 gene in human embryonic kidney cell line HEK293 models, and two peptide agonists (IELVW and IIGLVP) were prepared from high Fischer ratio oligopeptides of skipjack tuna and Mustelus griseus. Therefore, the antioxidant function of high Fischer ratio oligopeptides might be related to the exciting of the Keapl-Nrf2-ARE pathway.. In our previous experiment, the hepatocyte HL7702 model and human embryonic kidney epithelial cell line Hek293 model of Keapl-Nrf2-ARE on ARE-luciferase reporter have been established. In the following research, these models will be used for screening the active peptides with exciting ability on Keap1-Nrf2-ARE pathway. As expected results, 60-80 peptide agonists, including 3-5 highly reactive agonists, will be isolated from the high Fischer ratio oligopeptides of tuna, squid and cartilaginous fish muscles, and their structures will be elucidated on the basis of extensive spectroscopic data, including IR, NMR, MS, SRCD and X-ray. The exciting abilities and action mechanism of the isolated peptide agonists will also be researched on the hepatocyte HL7702 model. In addition, the in vivo effects on protecting liver of peptide agonists will be researched using the acute and chronic liver injury model of mice. Based on the structure and activity information, the structure-activity relationship and exciting mechanism on Keap1-Nrf2-ARE pathway of peptide agonists will be illuminated, and the dependency of physiological function of marine high Fischer ratio oligopeptides with their peptide agonists will be clarified.. The expected achievements will provide 3-5 kinds of candidates for research and development of high-efficiency antioxidant drugs, which will also provide significant technical support for high-value utilization of marine biological resources.