Development of KDM4B Inhibitors to Target Periodontal Disease Progression

Objectives: Periodontal disease (PD) affects 47% of the adult American population, and is characterized by bacterial-driven inflammatory bone loss. Present adjunctive therapies to manage PD have limited clinical value, and in some cases carry potential side effects that may outweigh their benefit. The activity of histone lysine demethylase 1A (KDM1A) reduces pro-inflammatory cytokine transcription and is exclusive of histone lysine demethylase 4B (KDM4B) activity. KDM4B inhibition has not yet been exploited for its immunomodulatory potential and holds promise as a mechanism to treat PD. The primary objective of this research is to validate KDM4B as a target for development of local inhibitors to treat PD.
Methods: Bone-marrow-derived-macrophages (BMDMs) were isolated from 12-week old C57BL/6 mice and pre-treated with three commercially available KDM4B inhibitors as well as a KDM1A inhibitor. Pre-treated BMDMs were challenged with Aggregatibacter actinomycetemcomitans lipopolysaccharide (A.a LPS) for 8 and 24 hours, after which RNA and supernatant proteins were collected for q-RT-PCR and ELISA analysis. Rigid receptor docking of ZINC database compounds into the KDM4B active site was computed using Molecular Operating Environment Software. Statistical significance was determined using unpaired t-tests (p<0.05).
Results: Pre-treatment of BMDMs with KDM4B inhibitors resulted in a significant reduction in A.a LPS induced pro-inflammatory cytokine transcription and translation in both males and females. This effect is modulated indirectly through increased KDM1A demethylation at H3K4, independent of H3K9 methylation activity. KDM4B protein abundance was significantly higher in areas of inflammatory infiltrate following live A.a injection in a murine calvarial model. Novel, but commercially available, inhibitors for KDM4B have been identified in silico through computational chemical screens.
Conclusions: KDM4B has been validated as a therapeutic target for treatment of PD through localized immunomodulation. Ongoing studies are focused on identification of lead compounds for development of a novel inhibitor library through QSAR and pharmacophore development.