Background Bacterial cyclic dinucleotides (CDNs), cyclic di-guanosine monophosphate (c-di-GMP), and cyclic di-adenosine monophosphate (c-di-AMP) upregulate interferon signaling proteins of human gingival fibroblasts (HGFs). However, the simultaneous effect of bacterial CDNs and lipopolysaccharides (LPS) on the HGF proteome is unknown.

Aim The aim was to apply an unbiased proteomics approach to evaluate how simultaneous exposure to CDNs and Porphyromonas gingivalis (Pg) LPS affect the global proteome of HGFs.

Methods The proteomic responses of HGFs were examined under three different treatment conditions (c-di-AMP+Pg LPS, c-di-GMP+Pg LPS, and Pg LPS alone) by label-free quantitative mass spectrometry analysis.

Results Simultaneous exposure to CDNs and Pg LPS significantly upregulated innate immunity-related and interferon signaling-related proteins, such as ubiquitin-like protein ISG15 (ISG15), deoxynucleoside triphosphate triphosphohydrolase (SAMHD1), interferon regulatory factor 9 (IRF-9), interferon-induced GTP-binding protein Mx (MX)1, and MX2. Interferon signaling pathway was the most significantly regulated canonical pathway in both CDN treatment groups.

Conclusion Simultaneous exposure to CDNs and Pg LPS stimulates the periodontal immune response by activating the anti-microbial cellular responses of HGFs with some notable differences from individual exposures.