Determination of the immunomodulatory role of microbiota derived postbiotics against inflammation associated with periodontal diseases

Periodontal diseases that can damage not only the dental tissue but also different systems of the body, are considered as a "silent" but important global outbreak considering their significant impacts on the huge audiences and socio-economic damage. The etiopathology of periodontal diseases is multifactorial and can be summarized by a complex series of links between microorganisms in dental biofilms and the host's immuno-inflammatory response. The aim of this thesis is to determine the immunomodulatory roles of various postbiotic mediators (PM: cell free supernatant, cell surface bound exopolysaccharide, release exopolysaccharide, cell lysate, cell surface protein, inactivated cell) of Lactiplantibacillus plantarum EIR/IF-1 strain isolated from breastfed infant fecal microbiota, against inflammation in human periodontal ligament fibroblast (iPDLF) cells caused by Porphyromonas gingivalis infection. For this purpose, target PMs were isolated using different methods and their doses that did not show cytotoxic effects on iPDLF cells were determined by MTT analysis. The effect of selected doses for each PM on P. gingivalis derived LPS-induced inflammation in iPDLF cells was determined by ELISA. When the data were evaluated in terms of IL-8 production, it was determined that LPS of P. gingivalis induced IL-8 production, while PMs reduced this effect. It has been also determined that the production of IL-10 with antiinflammatory properties, was dose-dependently induced by PMs. However, no significant change was detected in IFN-gamma production. In conclusion, although the use of PMs against periodontal diseases is a relatively new field, it has been shown that PMs produced by L. plantarum EIR/IF-1 strain, containing biologically active and functional molecules can be used as potential candidates to control periodontal tissue inflammation.