Identification of galectin‑10 as a biomarker for periodontitis based on proteomic analysis of gingival crevicular fluid.

Periodontitis is a chronic inflammatory disease caused by the gradual breakdown of tissues surrounding the teeth due to various factors. The disease has been frequently noted in dental outpatients for a number of years. Improvements are required to current diagnostic methods, which have limitations in assessing the condition and progression of periodontitis. The development of diagnostic biomarkers for periodontitis to increase the sensitivity and accuracy of diagnosis is important for the management of periodontitis. In the present study, whole gingival crevicular fluid (GCF) from patients with periodontitis and healthy individuals was characterized via liquid chromatography with tandem mass spectrometry. Label‑free quantification was used to identify the differentially abundant protein biomarkers. A total of 1,295 proteins were identified from the whole GCF of patients with periodontitis and healthy individuals via proteomic analysis. When analyzing biological processes, 'metabolic process' and 'cell organization and biogenes' were identified to play important roles in GCF under periodontitis conditions according to Gene Ontology. When analyzing molecular functions, 'catalytic activity' and 'protein binding' were the terms most enriched with differentially abundant proteins under periodontitis conditions. Galectin‑10 (Gal‑10) was one of the most upregulated proteins in the GCF of patients with periodontitis. The levels of prostaglandin E2 were increased in oral keratinocytes and gingival fibroblasts treated with recombinant (r)Gal‑10. The levels of interleukin‑8, matrix metalloproteinase 9 and C‑reactive protein were increased in the conditioned media (CM) of rGal‑10‑treated gingival fibroblasts. In addition, the CM of rGal‑10‑treated gingival fibroblasts induced osteoclast differentiation. These results suggested that Gal‑10 expression was increased in the GCF of patients with periodontitis and contributed to the process of osteoclastogenesis. Therefore, Gal‑10 may be a candidate biomarker for periodontitis.