Postdoctoral Fellow
Department of Immunology
email:
Beijing University, School of Dental Medicine, Beijing, China, DDS, 1997, Dental Science
Beijing University, School of Dental Medicine, Beijing, China, MSc, 1999, Oral Pathology
Boston University, School of Dental Medicine, Boston, MA, PhD, 2004, Oral Biology
My research interests involves the host immune response in periodontal disease tissue destruction, particularly in the area of osteoimmunology, the interaction between the immune system and bone metabolism and its role in the inflammatory bone destruction.
Periodontal disease is an inflammatory condition resulting from host-bacteria interactions, and triggering the host immune response against a constellation of periodontal microorganisms, which can be either protective or destructive. One of my studies focuses on the mechanisms of the host immune response in periodontal disease bone resorption. We have found that increased production of receptor activator of nuclear factor kappa B ligand (RANKL) occurs in B lymphocytes and contributes to the increased bone resorption in a B cell adoptive transfer model of periodontal disease. We are currently investigating the potential impact of immune-cell activation and regulation on periodontal bone resorption. Such studies will also help to elucidate mechanisms underlying other systemic bone destructive conditions, including osteoporosis and rheumatoid arthritis. The findings may ultimately be converted to potential treatments aimed at ameliorating periodontal as well as systemic bone loss.
Another research project is an investigation of the mechanism of bacterial genomic DNA-elicited immune responses that can generate protective immunity. Studies have shown that DNA immunization can induce host immune responses in both systemic and mucosal compartments. Naked genomic DNA is effective as a vaccine and epitopes encoded in such DNA can be expressed in recipient cells and can induce antigen-specific immune responses in the host. Our preliminary data indicated that injection of rats with Porphyromonas gingivalis (Pg) whole genomic DNA elicited a potent systemic and mucosal antibody response to Pg fimbriae, and reduced bacterial colonization and periodontal bone resorption. Our long-term goal is to elucidate the mechanisms by which bacterial genomic DNA activates host immune responses. This should be a prerequisite to the development of potential DNA-based therapeutic regimens that can be used to maximize protective immunity and eventually attenuate the disease process.
Han X, Kawai T, Eastcott JW, Taubman MA. 2006. Bacterial-responsive B lymphocytes induce periodontal bone resorption. J. Immunol. 176(1):625 C631.
Harada Y, Han X, Yamashita K, Kawai T, Eastcott JW, Smith DJ, Taubman MA. 2006. Effect of adoptive transfer of antigen-specific B cells on periodontal bone resorption. J. Periodontal Res. 41 (2) :101 C107.
Taubman MA, Smith DJ, Kawai T, Valverde P, Han X. 2005. Host-biofilm interface interactions lead to oral infectious diseases and contain promise for disease amelioration. International Congress Series 1284:93 C102.
Taubman MA, Valverde P, Han X, Kawai T. 2005. Immune response: The key to bone resorption in periodontal disease. J. Periodontol. 76(11-s) :2033 C2041.
Han X, Amar S. 2004. Secreted Frizzled-Related Protein 1 (sFRP1) protects fibroblast from ceramide-induced apoptosis. J. Biol. Chem. 279 (4):2832 C2840.
Han X, Amar S. 2003. Role of IGF-1 signaling in dental fibroblast apoptosis. J. Periodontol. 74(8):1 76 C182.
Amar S, Han X. 2003. The impact of periodontal infection on systemic diseases. Med. Sci. Monit. 9(12): RA291 CRA299.
Han X, Amar S. 2003. IGF-1 signaling enhances cell survival in periodontal ligament fibroblasts vs. gingival fibroblasts. J. Dent. Res. 82(6):454 C459.
Han X, Amar S. 2002. Identification of genes differentially expressed in cultured human periodontal ligament fibroblasts versus human gingival fibroblasts by DNA microarray analysis. J. Dent. Res. 81 (6) :399 C405.
Han X, Bolcato AL, Amar S. 2002. Identification of genes differentially expressed in cultured human osteoblasts versus human fibroblasts by DNA microarray analysis. Connect. Tissue Res. 43(1):63 C75.
Amar S, Han X. 2002. Regulation of tumour necrosis factor-gene expression. Appl. Genomics Proteomics 1(1):31 C44.
Han X, Gao Y. 2001. Clinical pathological study of lingual squamous cell carcinoma. Chin. J. Stomatol. 36(2):112 C115.
Han X, Gao Y. 2001. Retrospective study of clinical pathology of lingual squamous cell carcinoma. J. Modern Stomatol. 15(2):112 C113.
Han X, Gao Y. 1999. Histological classification of oral cancer and precancerous diseases (Part I). J. Modern Stomatol. 13(1):57 C60.
Han X, Gao Y. 1999. Histological classification of oral cancer and precancerous diseases (Part II). J. Modern Stomatol. 13(2):148 C150.
Han X, Gao Y. 1999. Case report: Subcutaneous cysticerosis. J. Modern Stoma.
