Periodontitis is a chronic oral inflammatory disease produced by bacteria. 
Gingival retraction and bone and connective tissues resorption are the hallmarks 
of this disease. Chronic periodontitis may contribute to the risk of onset or 
progression of neuroinflammatory pathological conditions, such as Alzheimer's 
disease. The main goal of the present study was to investigate if the role of 
epigenetic modulations is involved in periodontitis using human periodontal 
ligament stem cells (hPDLSCs) as an in vitro model system. hPDLSCs were treated 
with lipopolysaccharide of Porphyromonas gingivalis and the expression of 
proteins associated with DNA methylation and histone acetylation, such as DNMT1 
and p300, respectively, and inflammatory transcription factor NF-kB, were 
examined. Immunofluorescence, Western blot and next generation sequencing 
results demonstrated that P. gingivalis lipopolysaccharide significantly reduced 
DNA methylase DNMT1, while it markedly upregulated the level of histone 
acetyltransferase p300 and NF-kB in hPDLSCs. Our results showed that P. 
gingivalis lipopolysaccharide markedly regulate the genes involved in epigenetic 
mechanism, which may result in inflammation induction. We propose that P. 
gingivalis lipopolysaccharide-treated hPDLSCs could be a potential in vitro 
model system to study epigenetics modulations associated with periodontitis, 
which might be helpful to identify novel biomarkers linked to this oral 
inflammatory disease.