| Celiac disease(CD)is a chronic inflammatory bowel disease caused by the ingestion of gluten-containing proteins in genetically susceptible individuals(carrying the HLA-DQ2 or HLA-DQ8genes).The disease is characterized by oxidative damage,villi atrophy,inflammation and lining damage in the small intestine.The prevalence of celiac disease has risen to 1%-8% in western countries,and the incidence in China is increasing year by year.The diagnosis of celiac disease currently relies on the patient’s own highly specific serum Ig A anti-transglutaminase antibody test and examination for symptoms such as duodenal villous atrophy.The mainstream treatment is for patients to follow a strict gluten-free diet(GFD),but because gluten proteins are widely used in food processing,it is difficult for celiacs to completely avoid gluten protein intake in daily life.Therefore,there is a need to explore the development of new therapeutic approaches to assist in the treatment of celiac disease.It has been found that most of the antioxidant stress systems in celiac disease patients are damaged,and celiac sensitizing proteins induce inflammatory responses through oxidative stress,disrupt cell membrane integrity,induce cell damage and apoptosis,lead to intestinal epithelial barrier and dysfunction,and also promote celiac pathological responses.Therefore,it is believed that oxidative stress plays an important role in celiac disease,so inhibiting or alleviating oxidative stress in celiac disease may be an effective way to assist in the treatment of celiac disease.Black bean peptide(BSP)has been shown to not only inhibit oxidative stress but also have activities such as inhibition of inflammation,anti-cancer,and improvement of body immunity,but the effects of black bean peptide on celiac disease are not yet known.Therefore,in this paper,we will investigate whether BSP can alleviate oxidative damage in celiac disease cell models and explore its mechanism to provide a new strategy for the adjuvant treatment of celiac disease.Methods:(1)Exploring the mechanism of oxidative damage in celiac disease cell modelsCaco-2 cells,a human colon adenocarcinoma cell line that mimics partial sensitization of intestinal epithelial cells,were used for the experiments.Caco-2 cells were stimulated with the celiac sensitizing peptide P31-49 for 24 h.The cell viability,oxidative stress index,antioxidant enzyme activity,glutathione redox cycle and anti-oxidative stress signaling pathway of Caco-2 cells were used as references to explore the mechanism.(2)Mechanism of black bean peptides to alleviate oxidative damage in celiac disease cell modelsThe study used the screened antioxidant black bean peptide to treat Caco-2 cells and pretreated celiac disease cell model to determine whether the antioxidant black bean peptide has anti-sensitizing peptide toxicity by measuring the changes of cell viability,oxidative stress level,glutathione redox cycle,antioxidant enzyme activity and antioxidant signaling pathway,so as to investigate the mechanism of antioxidant damage of black bean peptide against celiac disease cell model.Results:(1)BSP1 pretreatment could improve cellular antioxidant capacity by increasing CAT and GR activities,and also inhibit the rise in Keap1 protein expression and upregulate Nrf2 protein expression in celiac disease sensitizing peptide p31-49 induced cells,protect CAT,GR,GST antioxidant enzyme activities,alleviate the imbalance of glutathione redox cycle,promote GCLC expression to improve cellular biosynthesis GSH rate,achieve scavenging of ROS and oxidative by-product MDA content,alleviate oxidative stress,reduce oxidative damage,and improve cell survival.(2)BSP3 pretreatment would increase cellular CAT and GR activity,and also inhibit the increase of Keap1 protein expression in p31-49-induced cells,attenuate Nrf2 protein ubiquitination,and upregulate Nrf2 protein expression,activate downstream genes GCLC and GCLM to regulate GSH synthesis,and protect and enhance GPx enzyme activity,alleviate the imbalance of glutathione redox cycle,achieve the purpose of reducing ROS level and alleviating oxidative stress,and finally increase the survival rate of sensitized cells.(3)BSP5 pretreatment also increased CAT activity and impaired the ubiquitination and degradation of Nrf2 protein by Keap1 through inhibition of p31-49 peptide-induced Keap1 protein expression,allowing the Nrf2 pathway to activate GCLC,GCLM to regulate GSH biosynthesis and protect CAT enzyme activity,acting together to inhibit intracellular ROS generation. |
