Millet Bran Protein Hydrolysate Displays The Anti-non-alcoholic Fatty Liver Disease Effect Via Activating Peroxisome Proliferator-Activated Receptor γ To Restrain Fatty Acid Uptake

Non-alcoholic fatty liver disease(NAFLD)that combined with complex exacerbating symptoms,such as liver fibrosis and cancer,is currently the most common liver disease worldwide,which has become a severe social burden due to its high prevalence.In present,there are no effective drugs for the treatment of NAFLD.Most patients with NAFLD are clinically asymptomatic,and few patients can present with symptoms of fatigue,dyspepsia,dull liver pain,and hepatosplenomegaly.Therefore,the development of dietary nutritional supplement against NAFLD is imminent.Millet bran is a by-product during the processing of millet.The study showed that the essential amino acids contents of millet bran protein account for 41.2%,which has high nutritional value and is the least allergenic protein of the grains,making it suitable as a dietary supplement for sub-healthy people.Recent studies have discovered that millet bran protein with medicinal value,which exhibits multiple efficacies,such as remodeling gut microbiota,anti-atherosclerosis and anti-tumor.In the present study,we found that millet bran protein hydrolysate(MBPH)obtained by in vitro gastrointestinal bionic digestion exhibited the potential of anti-NAFLD activity in vitro and in vivo;Meanwhile,the retardant of fatty acid uptake induced by PPARγ activation may be the critical factor for the anti-NAFLD activity of MBPH.The highlight of this project is the discovery of a new pharmacological mechanism of MBPH in anti-NAFLD effects,which is expected to be the next-generation dietary nutritional supplement for the prevention and treatment of NAFLD.The research results are as follows:1.MBPH displays an anti-NAFLD effect in vivo and in vitro.The study found that after MBPH intervention in Hep G2 cells induced by free fatty acids(FFAs),physiological and pathological indexes closely related to NAFLD,such as the decrease of intracellular triglyceride(TG)and total cholesterol(T-CHO)levels,and the alleviation of lipid accumulation;In the NAFLD mice model induced by high fat diet(HFD),we observed that the body weight and lipid levels of mice serum were significantly decreased,and the liver steatosis was significantly relieved.These data suggest that MBPH can display the anti-NAFLD activity by inhibiting the Hep G2 cell lipid accumulation in vitro and the hepatic steatosis in vivo.2.MBPH alleviates the hepatic steatosis by inhibiting fatty acid uptake.Results of free fatty acid content in cell culture medium showed that MBPH treatment significantly increased the content of FFAs in the culture medium.In addition,q PCR and western blot results showed that after MBPH treatment,the expression levels of fatty acid uptake-related genes,such as fatty acid binding protein 1(FABP1),fatty acid binding protein 2(FABP2),fatty acid binding protein 4(FABP4),cluster of differentiation 36(CD36),and carnitine palmitoyltransferase 1α(CPT-1α),were significantly down-regulated in vivo and in vitro.These results suggest that MBPH may play the anti-NAFLD effect by inhibiting the fatty acids uptake.3.The anti-NAFLD effect of MBPH mainly attributes to the retardant of fatty acid uptake induced by PPARγ activation.Transcriptome sequencing of liver tissue was used to analyze the differentially expressed genes in the liver of mice treated with MBPH,and it was found that PPARγ signaling pathway was significantly enriched,suggesting that PPARγ may play an important role in alleviating NAFLD effect of MBPH.Subsequently,the results showed that MBPH inhibited fatty acid uptake by activating PPARγ transcription activity to alleviate the NAFLD effect,which was further verificated in vitro and in vivo.These results suggest that the PPARγ signaling pathway mediates the anti-NAFLD effect of MBPH.In conclusion,MBPH obtained by in vitro simulated bionic digestion displays an anti-NAFLD effect in vivo and in vitro;Further,we found that MBPH treatment significantly attenuated the hepatic steatosis and lipid accumulation through activating the PPARγ transcription activity to restrain the fatty acid uptake,thus exerting the anti-NAFLD effect.The highlight of this study lies in which MBPH has the potential to be developed as a next-generation dietary nutritional supplement for the prevention and treatment of NAFLD.