The research focus of Dr. Xie's laboratory is nuclear receptor-mediated transcriptional regulation of genes that encode drug metabolizing enzymes and drug transporters. In addition to metabolizing drugs, the same enzyme and transporter systems are also responsible for the homeostasis of numerous endobiotic molecules. Therefore, besides drug metabolism and disposition, this regulation has broad implications in many human diseases, including liver diseases (fatty liver, liver fibrosis, liver cancer, and autoimmune hepatitis), endocrine disorders, metabolic syndrome, and cancers. Dr. Xie’s research is conducted using a combination of cell cultures and genetically engineered mice that include tissue and cell type-specific transgenic, knockout and humanized mice.