Dr. Libin Xu joined the Center for Ecogenetics and Environmental Health this year as an Affiliate Member. Dr. Xu is a researcher and Assistant Professor in the Department of Medicinal Chemistry in the UW School of Pharmacy.
Libin studies lipids, or fat molecules (cholesterol, vitamin A and vitamin E are examples), and their oxidation, a chemical reaction that generates free radicals that can damage DNA and body tissues. Having too many free radicals leads to oxidative stress, but this process can be prevented by antioxidants made in our own body or absorbed from diet. The Xu Lab studies how certain lipids are oxidized and metabolized, and how oxidation during lipid metabolism might be involved in human diseases.
The Xu lab is studying a rare disease called Smith-Lemli-Opitz syndrome or SLOS. SLOS is a cholesterol disorder that causes problems in the development of the central nervous system starting at embryonic stages. People who have SLOS have birth defects, intellectual disability and behavior problems such as autism.
SLOS is caused by a mutation in a gene (DHCR7) that makes an enzyme (3β-hydroxysterole-Δ7-reductase) that turns one lipid molecule (7-DHC) into another (cholesterol). The mutation means that SLOS patients have a lot of 7-DHC and not enough cholesterol. And it turns out that 7-DHC is extremely reactive toward oxidation, leading to the formation of free radicals and toxic oxidation products called oxysterols. In addition, some oxidative enzymes (cytochrome P450) can also turn 7-DHC into toxic oxysterols. This may be the problem underlying SLOS.
The goal of the work in Dr. Xu’s lab is to figure out the exact biochemical processes that lead to the broad phenotype of SLOS, and to find therapies to improve SLOS and other diseases caused by disrupted lipids. This research also will help scientists understand other intellectual and developmental disabilities that are associated with lipid metabolism problems and affect the function of the brain.
The research tools being developed in Dr. Xu’s lab to study lipids, based on advanced mass spectrometry, can also be used to study the side effects that common drugs might have on the metabolism of lipid molecules.
Working with the CEEH Community Outreach and Engagement Core (COEC), Libin Xu and Andrew Dinh in the Xu Lab have created a handout of interest to the general public: Fast Facts about Fat-Soluble Vitamins. Libin has also agreed to talk about lipid oxidation and his research at a Public Health Café next year.
Dr. Xu graduated with a B.Sc. in Chemistry from Nankai University, Tianjin, China. He earned his PhD in Organic Chemistry from the University of Illinois at Chicago, and did a post-doc at Vanderbilt where he became interested in lipid peroxidation and its role in human diseases. He received the Young Investigator Award from the Society for Free Radical Biology and Medicine in 2011 and the NIH Pathway to Independence Award from the National Institute of Child Health and Human Development in 2012. We welcome Libin Xu to the CEEH.