Periodontal disease affects 47% of Americans over 30 and is a growing global concern. Current treatments for periodontal disease focus on the mechanical elimination of periodontal biofilms. Very few treatments are available that target the rampant, unregulated host immune response that is ultimately responsible for tissue degradation. BET proteins have been shown to play critical roles in inflammatory gene regulation and are therefore potentially ideal therapeutic targets for treating periodontal disease. RVX-208 is a selective BET-inhibitor with a high affinity for Bromodomain 2 (BD2) as compared to BD1 in BET proteins. Our previous studies have shown that RVX-208 inhibits inflammatory cytokine production and suppresses osteoclast differentiation. Cell culture assays have provided proof of concept for RVX-208 and its feasibility as a treatment for periodontal disease. As such, our long term goal is to develop RVX-208 as a front-line treatment for periodontitis. The objectives of this study were to determine the ability of RVX-208 to reduce bone loss in a ligature-induced periodontitis model, and to further investigate the mechanisms through which RVX-208 mediates its anti-inflammatory and osteoclastogenesis-suppressive effects. The specific aims of this study were: 1) To further validate the in vivo effects of RVX-208 on a ligature-induced periodontitis model in rats, and 2) To determine the molecular mechanisms of RVX-208 on preventing alveolar bone loss in periodontal disease. To investigate, a ligature-induced periodontitis model was created in rodents. Those rodents were treated with increasing dosages of RVX-208 (0-2.5 mM) by subgingival injection every other day. After 2 weeks, the maxillae were harvested and analyzed via a micro-CT protocol that had been created and validated through statistical analyses. To study the ability of RVX-208 to suppress osteoclastogenesis, RAW264.7 cells were induced into osteoclasts by RANKL and then treated with RVX-208. To ensure RVX-208 was not species specific, THP-1 cells were challenged with either E. coli-LPS or P. gingivalis bacteria and then treated with RVX-208. Linear and volumetric micro-CT analysis showed that RVX-208 could significantly ameliorate bone loss in a ligature-induced periodontitis model. RVX-208 was shown to prevent osteoclast differentiation by suppressing the expression of genes closely associated with osteoclast differentiation and maturation. RVX-208 was found to not be species specific, as it was able to mediate its effects on a human cell line, and had consistent anti-inflammatory effects regardless of whole pathogen or LPS-induced inflammatory response. Therefore, RVX-208 is a promising therapeutic for treatment of periodontal diseases.
| Identifer | oai:union.ndltd.org:vcu.edu/oai:scholarscompass.vcu.edu:etd-6429 |
| Date | 01 January 2018 |
| Creators | Clayton, Nicholas J |
| Publisher | VCU Scholars Compass |
| Source Sets | Virginia Commonwealth University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | © The Author |
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