More about
Dr. Xia:

Dr. Xia 101
(for non-scientists)

Dr. Xia's CV in brief

Publications

Cardiovascular Biology Research Program

Dr. Xia In The News

A Deadly Mix-Up:
OMRF study zeroes in on culprit behind fatty liver disease in obese Oklahomans

A Vicious Cycle: New OMRF research sheds light on epileptic seizures

Lijun Xia, M.D., Ph.D. Associate Member, Cardiovascular Biology Research Program Merrick Foundation Distinguished Scientist Adjunct Associate Professor, Department of Biochemistry and Molecular Biology,   University of Oklahoma Health Sciences Center

Research Interests
O-glycosylation is increasingly appreciated as having a wide and yet largely unexplored spectrum of biological functions. Altered expression of mucin-type O-linked oligosaccharides (O-glycans) has been associated with tumor development and autoimmune diseases. Our research centers on functions of O-glycans in health and disease using gene-targeted mice as models.

Many membrane and secreted proteins are modified by O-glycans. The main O-glycan forms are core 1– and core 3–derived structures that are expressed primarily in endothelial, epithelial, and hematopoietic cells. Biosynthesis of core 1– and core 3–derived O-glycans is controlled, respectively, by the core 1 1,3-galactosyltransferase (T-synthase) and core 3 1,4-N-acetylglucosaminyltransferase (C3GnT).

To investigate O-glycan functions, we generated mice with global, tissue-specific, or inducible deficiencies in T-synthase and/or C3GnT. Our main goals are to: a) investigate biological functions of protein O-glycosylation in endothelial cells, epithelial cells, and hematopoietic cells, and b) determine mechanisms by which O-glycans regulate vascular development, inflammation, and tumorigenesis.

Current focuses are primarily on O-glycans in lymphangiogenesis and intestinal disease, two areas developed in my lab with high human disease relevance. We demonstrated that endothelial O-glycans regulate the O-glycoprotein podoplanin to control the separation of blood and lymphatic systems during embryonic and postnatal development. We are determining how podoplanin regulates lymphangiogenesis. Intestinal O-glycan expression is frequently altered in patients with colitis and colorectal tumors, which plays an unknown etiological role. We found that mice lacking intestinal O-glycans have impaired intestinal mucus barrier function and develop spontaneous colitis and colorectal tumors, supporting a causal role for abnormal O-glycans in the pathogenesis of these intestinal diseases. We are investigating mechanisms underlying this pathology. Many tumors metastasize via lymphatics in the absence of functional intratumor lymphatics. We will use mouse tumor models, including our colorectal tumor mouse model, to test the role of aberrant lymphangiogenesis in tumor metastasis. This direction synergizes our strengths in lymphangiogenesis and intestinal disease. Integrating data from these studies will provide a broad view of O-glycosylation function in health and disease.

Joined OMRF Scientific Staff in 2002.

Mailing Address
Cardiovascular Biology Research Program, MS 45
Oklahoma Medical Research Foundation
825 N.E. 13th Street
Oklahoma City, Oklahoma 73104

Contact Information
Phone: (405) 271-7892
Lab: (405) 271-3979
Fax: (405) 271-3137
E-mail: Lijun-Xia@omrf.org