Lijun Xia, M.D., Ph.D.
Adjunct Professor, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center
Many have never heard of O-glycans. But without it, you probably wouldn’t be alive.
O-glycans are a sugar that your body makes, and are the focus of my research. In my lab, we’ve found O-glycans are important in the development of the lymphatic system, which moves fat and fatty acids throughout the body. Without this sugar, the body doesn’t know if it should grow blood vessels or pieces of the lymphatic system or how to connect them properly. This can lead to fatty liver disease, a condition that affects as much as one-quarter of the world’s population and can lead to liver inflammation, cirrhosis and liver cancer.
My lab is also studying how lymphatic drainage can be used in the diagnosis and treatment of cancer. The lymphatic system is responsible for carrying cancerous cells between various parts of the body in a process called metastasis. We are now working ot understand how to prevent these potentially deadly conditions.
In patients with colitis and colorectal tumors, we’ve found that O-glycans are different than in those with normal intestinal systems. There’s a chance a lack of this sugar in the intestines might cause these diseases. So we’re also exploring this hypothesis—in hopes of using the knowledge we gain to treat intestinal diseases.
M.D., Binzhou Medical College, China, 1982
M.S., Qingdao University Medical College, China, 1990
Ph.D., Soochow University Medical College, China, 1995
Honors and Awards
2003 Scientist Development Award, American Heart Association
2006 Scientific Consultant, American Stem Cell, Inc., CA
2007 Merrick Award for Outstanding Research, Oklahoma Medical Research Foundation
2009 Merrick Foundation Distinguished Scientist, Oklahoma Medical Research Foundation
2012 Edward L. and Thelma Gaylord Prize for Scientific Achievement
American Society of Hematology
Member, Society for Glycobiology
Joined OMRF Scientific Staff in 2002.
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 b1,3-galactosyltransferase (T-synthase) and core 3 b1,4-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.
Bergstrom KS, Xia L. Mucin-type O-glycans and their roles in intestinal homeostasis. Glycobiology 2013. [Abstract] EPub
Ahmed I, Roy B, Chandrakesan P, Venugopal A, Xia L, Jensen R, Anant S, Umar S. Evidence of functional cross talk between the Notch and NF-kappaB pathways in nonneoplastic hyperproliferating colonic epithelium. Am J Physiol Gastrointest Liver Physiol 304:G356-G370, 2013. [Abstract]
Kim YM, Lee JY, Xia L, Mulvihill JJ, Li S. Trisomy 8: a common finding in mouse embryonic stem (ES) cell lines. Mol Cytogenet 6:3, 2013. [Abstract]
Fu J, Wei B, Wen T, Johansson ME, Liu X, Bradford E, Thomsson KA, McGee S, Mansour L, Tong M, McDaniel JM, Sferra TJ, Turner JR, Chen H, Hansson GC, Braun J, Xia L. Loss of intestinal core 1-derived O-glycans causes spontaneous colitis in mice. J Clin Invest 121:1657-1666, 2011. [Abstract]
Yago T, Fu J, McDaniel JM, Miner JJ, McEver RP, Xia L. Core 1-derived O-glycans are essential E-selectin ligands on neutrophils. Proc Natl Acad Sci U S A 107:9204-9209, 2010. [Abstract]
An G, Wang H, Tang R, Yago T, McDaniel JM, McGee S, Huo Y, Xia L. P-selectin glycoprotein ligand-1 is highly expressed on Ly-6Chi monocytes and a major determinant for Ly-6Chi monocyte recruitment to sites of atherosclerosis in mice. Circulation 117:3227-3237, 2008. [Abstract]
Fu J, Gerhardt H, McDaniel JM, Xia B, Liu X, Ivanciu L, Ny A, Hermans K, Silasi-Mansat R, McGee S, Nye E, Ju T, Ramirez MI, Carmeliet P, Cummings RD, Lupu F, Xia L. Endothelial cell O-glycan deficiency causes blood/lymphatic misconnections and consequent fatty liver disease in mice. J Clin Invest 118:3725-3737, 2008. [Abstract]
An G, Wei B, Xia B, McDaniel JM, Ju T, Cummings RD, Braun J, Xia L. Increased susceptibility to colitis and colorectal tumors in mice lacking core 3-derived O-glycans. J Exp Med 204:1417-1429, 2007. [Abstract]
Cardiovascular Biology Research Program, MS 45
Oklahoma Medical Research Foundation
825 N.E. 13th Street
Oklahoma City, OK 73104
Phone: (405) 271-7892
Lab: (405) 271-3979
Fax: (405) 271-3137
Jianxin Fu, M.D., Ph.D.
Research Assistant Member
Jane Song, Ph.D.
Assistant Staff Scientist
Kirk Bergstrom, Ph.D.
Kai Song, Ph.D.
John Michael McDaniel
Senior Research Assistant