Periodontitis is an inflammatory disease triggered by host immune response to pathogenic microorganisms in the periodontal biofilm. B lymphocytes are densely infiltrated at the site of infection and are a primary source of receptor activator of NF-:B ligand (RANKL), a cytokine that plays a pivotal role in osteoclast differentiation and inflammatory bone resorption. Our long-term goal is to determine the molecular mechanisms which control immune cell-mediated periodontal bone resorption in periodontitis for preventive and therapeutic purposes. Toll-like receptors (TLRs) recognize pathogen associated molecular patterns (PAMPs) and TLR signaling pathways play an important role in regulating immune cell functions, including cytokine production, phagocytosis, and programmed cell death (apoptosis). While various B lymphocyte subsets express multiple TLRs, including TLR4 and TLR9, the role of TLR signaling on B cell apoptosis is entirely unclear. The central hypothesis of this application is that co-activation of TLR4/TLR9 signaling induces apoptosis of RANKL-producing B cells, thus diminishing B cell-mediated periodontal bone resorption. Our hypothesis is based on our preliminary results demonstrating that co-stimulation with TLR4/9 agonists, LPS and CpG ODN, elevated expressions of TLR4 and TLR9 and increased B cell apoptosis in cultured rat splenocytes. In this application we will explore how TLR4/TLR9 signaling regulates B cell apoptosis using both in vitro and in vivo models.
In Specific Aim 1, we will determine if co-activation of TLR4 and TLR9 induce RANKL-expressing B cell apoptosis, thereby inhibiting B cell-mediated osteoclastogenesis, using an in vitro osteoclastogenesis model.
In Specific Aim 2, we will determine whether co-activation of TLR4/TLR9 induces B cell apoptosis and decreases B cell-mediated periodontal bone resorption in vivo. We have developed an in vivo model of adoptive B cell transfer/gingival antigen injection that can be used to undertake the proposed research. The rationale for the proposed research is that, once it is known how TLR signaling controls RANKL-expressing B cell apoptosis, therapeutic strategies based on induction of RANKL-expressing B cell apoptosis, therefore, inhibition of B cell-mediated osteoclastogenesis may be effective in preventing bone resorption and tooth loss in people with periodontitis. It is also expected that what is learned here could be applicable to the understanding of other immune-mediated bone-resorptive disorders.

Public Health Relevance

An estimated 80% of American adults have some form of periodontal disease, causing oral bone destruction and ultimately leading to tooth loss. The expenditures for treating these conditions far exceed $6 billion/year. Current treatments do not offer complete amelioration of bone loss around teeth because they do not inhibit the biological causes of periodontal bone loss. This application will provide us new knowledge about host immune response in periodontal disease pathogenesis and contribute to development of therapeutic strategies that are effective in preventing tooth loss in people with periodontal disease.

National Institute of Health (NIH)
National Institute of Dental & Craniofacial Research (NIDCR)
Exploratory/Developmental Grants (R21)
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Oral, Dental and Craniofacial Sciences Study Section (ODCS)
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Denucci, D J
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Forsyth Institute
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Kanzaki, Hiroyuki; Movila, Alexandru; Kayal, Rayyan et al. (2017) Phosphoglycerol dihydroceramide, a distinctive ceramide produced by Porphyromonas gingivalis, promotes RANKL-induced osteoclastogenesis by acting on non-muscle myosin II-A (Myh9), an osteoclast cell fusion regulatory factor. Biochim Biophys Acta 1862:452-462
Hu, Yang; Yu, Pei; Yu, Xinbo et al. (2017) IL-21/anti-Tim1/CD40 ligand promotes B10 activity in vitro and alleviates bone loss in experimental periodontitis in vivo. Biochim Biophys Acta 1863:2149-2157
Lin, Mei; Hu, Yang; Wang, Yuhua et al. (2017) Different engagement of TLR2 and TLR4 in Porphyromonas gingivalis vs. ligature-induced periodontal bone loss. Braz Oral Res 31:e63
Liu, Zhiqiang; Hu, Yang; Yu, Pei et al. (2017) Toll-like receptor agonists Porphyromonas gingivalis LPS and CpG differentially regulate IL-10 competency and frequencies of mouse B10 cells. J Appl Oral Sci 25:90-100
Shi, J; Liu, Z; Kawai, T et al. (2017) Antibiotic administration alleviates the aggravating effect of orthodontic force on ligature-induced experimental periodontitis bone loss in mice. J Periodontal Res 52:725-733
Yu, Xiaoqian; Wang, Yuhua; Lin, Jiang et al. (2016) Lipopolysaccharides-Induced Suppression of Innate-Like B Cell Apoptosis Is Enhanced by CpG Oligodeoxynucleotide and Requires Toll-Like Receptors 2 and 4. PLoS One 11:e0165862
Chen, W; Gao, B; Hao, L et al. (2016) The silencing of cathepsin K used in gene therapy for periodontal disease reveals the role of cathepsin K in chronic infection and inflammation. J Periodontal Res 51:647-60
Nishimura, Kazuaki; Shindo, Satoru; Movila, Alexandru et al. (2016) TRAP-positive osteoclast precursors mediate ROS/NO-dependent bactericidal activity via TLR4. Free Radic Biol Med 97:330-341
Lin, Mei; Wang, Zuomin; Han, Xiaozhe (2015) B Cells with Regulatory Function in Animal Models of Autoimmune and Non-Autoimmune Diseases. Open J Immunol 5:9-17
Lin, Mei; Lin, Jiang; Wang, Yuhua et al. (2015) Lipopolysaccharide Attenuates CD40 Ligand-Induced Regulatory B10 Cell Expansion and IL-10 Production in Mouse Splenocytes. Open J Immunol 5:1-8

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