Junichiro Irie is an assistant professor at the Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine at Keio University School of Medicine in Japan. He graduated from Keio University School of Medicine in 1996 and received scientific and clinical training for 7 years. Afterward, he became a postdoctoral fellow at the Division of Rheumatology and Clinical Immunology at the University of Pittsburgh School of Medicine in the U.S.A. He became a vice director of the Diabetes Center at Kitasato University Hospital in Japan in 2006 and has been a member of the Division of Endocrinology, Metabolism, and Nephrology at Keio University School of Medicine since 2007. He has been working on the physiology and pathology of obesity and type 2 diabetes in experimental models and patients in clinics. He focuses on the roles of intestinal microbiota and their metabolites to develop a novel treatment for metabolic disorders.