New strategies for the control of periodontitis

Abstract

We aim to establish the bases for the development of new strategies for the control of periodontitis. Our hypothesis is that the balance between the oral microbiota-immune response, lost in periodontitis, could be obtained by favoring the colonization of the oral cavity with beneficial bacterial species and by modulating the immune response. The first project aims to test if saliva differs according to the periodontal condition, identifying potential biomarkers in localized aggressive and chronic periodontitis and their controls. Microbiome will be determined by 16SrRNA sequencing in oral and fecal samples. Proteome of saliva (total and parotid) and of the acquired pellicle will be determined. The expanded exome will be investigated. We hope to demonstrate that differences in saliva composition, due to genomic variations, are correlated with differences in oral microbiome associated with each periodontal condition. The second project aims to correlate functional aspects of saliva with its composition. Differences in affinity of microbial groups to the pellicle will be determined by biofilm formation assays, with inocula formed by biofilm samples and isolated species. Depending on the initial data, recombinant proteins or synthetic peptides can be used in further functional analysis. The third project aims to test if probiotics present antagonism against the oral pathogenic microbiota. Lactobacillus and Bifidobacterium species will be evaluated regarding their effect on P. gingivalis and A. actinomycetemcomitans. The ability of probiotics to inhibit growth and/or virulence factors expression and to compete for adhesion sites in gingival epithelial cells will be determined. The effect of probiotics on manipulating the oral and gut microbiota will be evaluated by using the Shime model added with the mouth compartment. The effect of probiotics on the composition of dental biofilm and their cariogenic potential will be determined in situ. We hope to select the probiotic strains able to manipulate the oral microbiota, by antagonizing with periodontopathogens. The fourth project aims to determinate the ability of probiotics to modulate the immune response. Co-culture assays with probiotics, periodontopathogens and epithelial cells (OBA-09 and primary), human monocytes (THP-1 and peripherical) and murine (wild and KO in IL-1r, IL-18, TLR-2 and TLR-4) BMCs differentiated in macrophages, and dendritic cells will be used to test for cytokines production, gene expression, signaling pathways and functionality on lymphocytes subtypes differentiation. Probiotics will be tested in periodontitis animal models with P. gingivalis and A. actinomycetemcomitans in normal and diabetic mice. We hope to select the probiotic strains able to colonize the oral cavity and to induce an immune response favoring a health-associated microbiota, in balance with the host. Aiming to test if probiotics can be used as adjuvant to the periodontal treatment, the fifth project will evaluate the effect of probiotics on the oral and gut microbiota in humans, and on clinical parameters and cytokines production. Probiotics-containing lozenges will be used in periodontally treated patients for 180 days. We hope to demonstrate that probiotics are able to reestablish the balance in periodontitis patients during maintenance treatment phase, and thus suggest their use as a therapeutic strategy in the control of periodontitis, and possibly of other associated conditions. These data will contribute to the establishment of strategies able to interfere with dysbiosis and host immune response to the resident microbiota, favoring health. (AU)