Dr. Ta-Chiang Liu is an associate professor of pathology and immunology and associate chief of the division of anatomic and molecular pathology at Washington University. Dr. Liu’s clinical expertise is in gastrointestinal pathology, and his research focuses on how the function of a specialized type of epithelial cell with immune function (Paneth cells) can integrate the effect of gene-environment interactions in inflammatory bowel disease (IBD). His team recently showed that LRRK2 kinase in macrophages can be activated either by genetic mutations alone (such as LRRK2 G2019S) or by interaction between the autophagy gene ATG16L1 and cigarette smoking, both key pathogenic factors for Crohn’s disease, a type of IBD. His group also demonstrated that the abnormal Paneth cells in mice with mutant Lrrk2 can be rescued by an LRRK2 kinase inhibitor that does not enter the brain, indicating a functional link between Parkinson’s disease and Crohn’s disease.