title: Kefir peptides prevent high-fructose corn syrup-induced non-alcoholic fatty liver disease in a murine model by modulation of inflammation and the JAK2 signaling pathway.
abstract: In recent years, people have changed their eating habits, and high-fructose-containing bubble tea has become very popular. High-fructose intake has been suggested to be a key factor that induces non-alcoholic fatty liver disease (NAFLD). Kefir, a fermented milk product composed of microbial symbionts, has demonstrated numerous biological activities, including antibacterial, antioxidant and immunostimulating effects. The present study aims to evaluate the effects of kefir peptides on high-fructose-induced hepatic steatosis and the possible molecular mechanism.
  
  
  
  An animal model of 30% high-fructose-induced NAFLD in C57BL/6J mice was established. The experiment is divided into the following six groups: (1) normal: H2O drinking water; (2) mock: H2O+30% fructose; (3) KL: low-dose kefir peptides (50 mg kg-1)+30% fructose; (4) KM: medium-dose kefir peptides (100 mg kg-1)+30% fructose; (5) KH: high-dose kefir peptides (150 mg kg-1)+30% fructose; and (6) CFM: commercial fermented milk (100 mg kg-1)+30% fructose. The results show that kefir peptides improve fatty liver syndrome by decreasing body weight, serum alanine aminotransferase, triglycerides, insulin and hepatic triglycerides, cholesterol, and free fatty acids as well as the inflammatory cytokines (TNF-α, IL-6 and IL-1β) that had been elevated in fructose-induced NAFLD mice. In addition, kefir peptides markedly increased phosphorylation of AMPK to downregulate its targeted enzymes, ACC (acetyl-CoA carboxylase) and SREBP-1c (sterol regulatory element-binding protein 1), and inhibited de novo lipogenesis. Furthermore, kefir peptides activated JAK2 to stimulate STAT3 phosphorylation, which can translocate to the nucleus, and upregulated several genes, including the CPT1 (carnitine palmitoyltransferase-1) involved in fatty acid oxidation.
  
  
  
  Our data have demonstrated that kefir peptides can improve the symptoms of NAFLD, including body weight, energy intake, inflammatory reaction and the formation of fatty liver by activating JAK2 signal transduction through the JAK2/STAT3 and JAK2/AMPK pathways in the high-fructose-induced fatty liver animal model. Therefore, kefir peptides may have the potential for clinical application for the prevention or treatment of clinical metabolic syndrome.
authors.affiliation: Department of Bioresources, Da-Yeh University, Changhwa, Taiwan.
authors.forename: H L
authors.initials: HL
authors.lastname: Chen
authors.affiliation: Department of Life Sciences and Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan.
authors.forename: T C
authors.initials: TC
authors.lastname: Tsai
authors.affiliation: Department of Life Sciences and Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan.
authors.forename: Y C
authors.initials: YC
authors.lastname: Tsai
authors.affiliation: Graduate Institute of Veterinary Pathology, National Chung Hsing University, Taichung, Taiwan.
authors.forename: J W
authors.initials: JW
authors.lastname: Liao
authors.affiliation: Department of Life Sciences and Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan.|Department of Internal Medicine, China Medical University Hospital, Taichung, Taiwan.
authors.forename: C C
authors.initials: CC
authors.lastname: Yen
authors.affiliation: Department of Life Sciences and Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan.|Rong-Hsing Translational Medicine Center, iEGG Center, National Chung Hsing University, Taichung, Taiwan.
authors.forename: C M
authors.initials: CM
authors.lastname: Chen
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D001835:Body Weight / Q000187:drug effects*; D016207:Cytokines / Q000097:blood; D004195:Disease Models, Animal; D002149:Energy Intake / Q000187:drug effects; D066248:High Fructose Corn Syrup / Q000494:pharmacology*; D007249:Inflammation / Q000378:metabolism*; D053614:Janus Kinase 2 / Q000378:metabolism*; D000070716:Kefir; D008297:Male; D051379:Mice; D065626:Non-alcoholic Fatty Liver Disease / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control*; D010766:Phosphorylation; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D016207:Cytokines; D066248:High Fructose Corn Syrup; D000410:Alanine Transaminase; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2