The interrelationship between periodontal disease, obesity-related hyperlipidemia and mechanical forces as well as their modulating effects on the epigenetic profile of periodontal ligament (PdL) cells are assumed to be remarkably complex. The PdL serves as connective tissue between teeth and alveolar bone for pathogen defense and inflammatory response to mechanical stimuli occurring during tooth movement. Altered inflammatory signaling could promote root resorption and tooth loss. Hyperinflammatory COX2/PGE2 signaling was reported for human PdL fibroblasts (HPdLF) concomitantly stressed with P. gingivalis lipopolysaccharides and compressive force after exposure to palmitic acid (PA). The aim of this study was to investigate to what extent this is modulated by global and gene-specific changes in histone modifications. Quantitative expression of epigenetic key players and global H3Kac as well as H3K27me3 levels were evaluated in dual stressed HPdLF exposed to PA revealing a decreased force-related reduction in repressive H3K27me3. UNC1999-induced H3K27me3 inhibition reversed the hyperinflammatory response of dual-stressed PA-cultures characterized by COX2 expression, PGE2 secretion and THP1 adhesion. Reduced expression of the anti-inflammatory cytokine IL10 and increased association of H3K27me3 at its promoter-associated sites were reversed by inhibitor treatment. Thus, the data highlight an important epigenetic interplay between different stimuli to which the PdL is exposed.
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Subject: Biology and Life Sciences - Biochemistry and Molecular Biology
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