Han (Hannah) Fang, PhD
Postdoctoral Fellow
Department of Biochemistry and Biomedical Sciences 
McMaster University
Hamilton, ON, Canada  

This conference is part of the the IRCM Early-Career Scientist Seminar Series (ECS3), a groundbreaking initiative whose mission is to showcase early career scientists. This is a great opportunity to discover the exciting projects of these researchers in training in front of a multidisciplinary audience.

About this conference
Obesity disrupts host-microbiota metabolic interactions, contributing to insulin resistance and fatty liver disease, yet the specific microbial metabolites involved remain unclear. My recent study, published in Cell Metabolism, identifies microbiota-derived D-lactate as a previously unrecognized regulator of host glucose and lipid metabolism. We found that circulating D-lactate levels were elevated in obese mice and humans, and that gut bacteria are the dominant source of this metabolite. In mice, D-lactate increased hepatic glycogen, triglycerides, and blood glucose more than L-lactate and was metabolized by hepatocytes into pyruvate, TCA intermediates, lipids, and glucose. Colonization with D-lactate-producing bacteria raised blood glucose, demonstrating its metabolic impact. Strikingly, we found a biocompatible polymer “gut substrate trap” that sequesters D-lactate in the intestinal lumen, forcing its excretion. This intervention lowered blood glucose, insulin resistance, hepatic inflammation, and fibrosis in obese mice with metabolic dysfunction-associated fatty liver disease. Our findings reveal microbial D-lactate as
a key metabolic substrate linking gut microbiota to host energy metabolism and introduce gut substrate trapping as a novel therapeutic strategy for obesity-related metabolic disorders.

About Han (Hannah) Fang
Dr. Han (Hannah) Fang is a postdoctoral fellow at McMaster University (Department of Biochemistry and Biomedical Sciences) in Dr. Jonathan Schertzer’s lab. She studies gut microbiota-host metabolic crosstalk, with an emphasis on microbial metabolites that regulate glucose and lipid metabolism in obesity and metabolic-associated fatty liver disease. Dr. Fang received her PhD in Biomedical Science from Auburn University under Dr. Robert Judd. She then trained at the Pennington Biomedical Research Center with Dr. Thomas Gettys, where she investigated the metabolic effects of dietary methionine restriction before joining McMaster.