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Faculty
Richard G. LeBaron, Ph.D. Research Interests Extracellular matric (ECM) molecules are found in essentially all tissues and are fundamental for our normal growth and health. ECM molecules have biological activities that range from structural support to the regulation of transcription activity. My major research interests at present focus on three areas of ECM biology. One area is the study of proteoglycans. We are examining the biological functions of a large chondroitin sulfate proteoglycan (versican). The amino acid sequence of versican contains several potential binding elements, to include a hyaluronan binding domain at the N-terminus and two EGF-life units, a lectin-like unit and a complement regulatory protein-like unit at the C-terminus. The presence of these structural motifs suggest that versican interacts with several molecules and may play a structural role in tissue by “linking” molecules together. Indeed, versican binds to hyaluronan with high affinity (Kd in the nM range). We are now studying the role of versican in the central nervous system (CNS). Versican is synthesized by glial cells in the CNS and co-localizes with myelinated axons. The untrastructural localization of versican with myelin and with glial cells will be examined by light microscopy and transmission electron microscopy. The structure of versican isolated from normal brain tissue and demyelinated brain tissue (such as multiple sclerosis-afflicted tissue) and potential ligand for the C-terminus of versican will be studied by immunological and biochemical methods. Recent Publications Lemire JM, Chan CK, Bressler S, Miller J, Lebaron RG, Wight TN. Interleukin-1beta selectively decreases the synthesis of versican by arterial smooth muscle cells. J Cell Biochem. 2007 Jan 16; [Epub ahead of print] Hernandez RV, Navarro MM, Rodriguez WA, Martinez JL Jr, LeBaron RG. Differences in the magnitude of long-term potentiation produced by theta burst and high frequency stimulation protocols matched in stimulus number. Brain Res Brain Res Protoc. 2005 May;15(1):6-13. Richards JS, Hernandez-Gonzalez I, Gonzalez-Robayna I, Teuling E, Lo Y, Boerboom D, Falender AE, Doyle KH, LeBaron RG, Thompson V, Sandy JD. Regulated expression of ADAMTS family members in follicles and cumulus oocyte complexes: evidence for specific and redundant patterns during ovulation. Biol Reprod. 2005 May;72(5):1241-55. Temenoff JS, Park H, Jabbari E, Sheffield TL, LeBaron RG, Ambrose CG, Mikos AG. In vitro osteogenic differentiation of marrow stromal cells encapsulated in biodegradable hydrogels. J Biomed Mater Res A. 2004 Aug 1;70(2):235-44. Suwiwat S, Ricciardelli C, Tammi R, Tammi M, Auvinen P, Kosma VM, LeBaron RG, Raymond WA, Tilley WD, Horsfall DJ. Expression of extracellular matrix components versican, chondroitin sulfate, tenascin, and hyaluronan, and their association with disease outcome in node-negative breast cancer. Clin Cancer Res. 2004 Apr 1;10(7):2491-8. Ferguson JW, Mikesh MF, Wheeler EF, LeBaron RG. Developmental expression patterns of Beta-ig (betaIG-H3) and its function as a cell adhesion protein. Mech Dev. 2003 Aug;120(8):851-64. Sakko AJ, Ricciardelli C, Mayne K, Suwiwat S, LeBaron RG, Marshall VR, Tilley WD, Horsfall DJ. Modulation of prostate cancer cell attachment to matrix by versican. Cancer Res. 2003 Aug 15;63(16):4786-91. Ferguson JW, Thoma BS, Mikesh MF, Kramer RH, Bennett KL, Purchio A, Bellard BJ, LeBaron RG. The extracellular matrix protein betaIG-H3 is expressed at myotendinous junctions and supports muscle cell adhesion. Cell Tissue Res. 2003 Jul;313(1):93-105. LeBaron RG, Hernandez RV, Orfila JE, Martinez JL Jr. An integrin binding peptide reduces rat CA1 hippocampal long-term potentiation during the first few minutes following theta burst stimulation. Neurosci Lett. 2003 Mar 27;339(3):199-202. Huang W, Anvari B, Torres JH, LeBaron RG, Athanasiou KA. Temporal effects of cell adhesion on mechanical characteristics of the single chondrocyte. J Orthop Res. 2003 Jan;21(1):88-95.
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