Food-derived Dityrosine Mediate Disorders Of Hepatic Energy Metabolism And Intervention Studies

Dityrosine(DT)is a typical casein(Tyr)oxidation product that is widely found in meat and dairy processing systems and has received attention from the food science research community for the health risks associated with it.The potential biohazards of DT currently include increased levels of tissue free radicals,accumulation of oxidised protein products and impaired energy metabolism.Subsequently,the elucidation of the molecular mechanisms of DT-induced tissue damage and the development of effective nutritional intervention strategies have important theoretical and practical implications for the development of protein nutrition theory,food processing technology and public health quality.First,DT-mediated liver tissue injury and lycopene(LYC)intervention in mice were investigated.Twenty-four 4-week-old C57BL/6J male mice were randomly divided into three groups:the Con group,the DT group and the LYC group after one week of pre-feeding and gavaged with 420μg/k-BW Tyr,420μg/k-BW DT and 420μg/k-BW DT+5μg/k-BW LYC,respectively,and tissue samples were collected after 35 days of continuous gavage for analysis.The results showed that DT gavage caused a large accumulation of hepatic protein oxidation products(DT,AOPPs),lipid peroxidation products(MDA)and free fatty acids(FFA),and an increase in plasma transaminase(AST,ALT)levels,leading to disruption of lipid metabolism and liver function damage.At the same time,DT disrupts mitochondrial function and disturbs the balance of energy metabolism,as evidenced by a significant decrease in plasma and hepatic thyroid hormone(T3 and T4)levels,a decrease in the level of the energy metabolism substrate acetyl Co A,a decrease in the NADH/NAD~+ratio,a decrease in ATPase activity and a lack of ATP production.In addition,DT gavage led to a significant increase in the level of reactive oxygen species(ROS),a significant decrease in total antioxidant capacity(T-AOC),the content of non-enzymatic antioxidants GSH/GSSG and the activities of antioxidant enzymes(SOD and Mn-SOD).LYC intervention was effective in increasing ATP content,improving lipid accumulation and restoring thyroid hormone levels,but had no significant effect on increasing energy substrate levels,mitochondrial biosynthesis and membrane potential.Next,a DT-damaged Hep G2 cell model was established to further explore the mechanisms of DT oxidative damage and LYC intervention.The results showed that incubation with 500μM DT for 72 h led to a decrease in cell survival and an increase in ROS.Transcriptome sequencing analysis revealed that DT mainly affected energy and lipid metabolism pathways,not only disrupting mitochondrial membrane potential and blocking acetyl Co A utilization,but also reducing ATPase activity and causing insufficient ATP production,but not significantly affecting electron transport complex activity.micro RNA sequencing analysis combined with q PCR validation revealed that DT up-regulated mi R-144-3p levels and inhibited IRG1 and IRG1 from the transcriptional level.inhibited IRG1 and TIGAR gene expression from the transcriptional level.On the one hand,it inhibited the synthesis of ferredoxin by mediating the activity of ferredoxinase,leading to a decrease in the activity of Nrf2 antioxidant signaling pathway,as evidenced by a significant decrease in T-AOC,non-enzymatic antioxidant GSH/GSSG content and the activities of antioxidant enzymes GPX,CAT and Mn-SOD,accelerating the imbalance of redox homeostasis.On the other hand,mi R-144-3p may inhibit the SIRT1-PGC1αsignaling pathway by targeting TIGAR,causing a decrease in mitochondrial biosynthesis and further oxidative damage to cells.LYC intervention could exert antioxidant effects by enhancing the activity of T-AOC and endogenous mitochondrial antioxidant enzymes,scavenging excess free radicals;at the same time,restoring mitochondrial membrane potential and electron transport chain It also restored mitochondrial membrane potential and electron transport chain activity and promoted energy production,but had no significant effect on increasing energy substrate levels.In summary,foodborne DT intake adversely affected tissue mitochondrial function,energy metabolism and thyroid hormone secretion levels,which were closely related to its effects on lipid metabolism and energy metabolism pathways,especially upregulation of mi R-144-3p levels.Lycopene can better maintain tissue redox homeostasis,mitochondrial function and thyroid hormone levels,reduce hepatic fatty acid accumulation and restore the amount of ATP production,and can be subsequently applied in dietary intervention strategies to reduce the health risks of food oxidized proteins.