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OBJECTIVE: Monoamine oxidase (MAO) inhibitors reduce inflammation in a number of in vitro and in vivo models. This finding led to the development of a novel MAO-B selective inhibitor (RG0216) designed to reduce blood-brain barrier penetration. To elucidate RG0216's regulatory role in inflammation-relevant signaling pathways, we employed a transcriptome analytic approach to identify genes that are differentially regulated by RG0216 and then globally identified which inflammation-relevant biological signaling pathways were altered by this drug. MATERIALS AND METHODS: Primary human gingival keratinocyte (HGK) cells were treated with RG0216, and RNA was extracted (4 h). RNAseq transcriptome analysis was utilized to identify differentially expressed genes (DEGs), while Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used to identify significantly enriched biological pathways. Relevant genes associated with these pathways and RG0216 regulation of Porphyromonnas gingivalis lipopolysaccharide (PgLPS)-induced cytokine/ chemokine expression were evaluated using the real-time quantitative reverse-transcription polymerase chain reaction (RT-qPCR) approach. RESULTS: RG0216 significantly altered the expression of 50 DEGs in HGK cells. Using GO and KEGG analytic approaches, these genes were associated with the biological pathways relevant to mitogen-activated protein kinase (MAPK) and MAPK phosphatases. These phosphatases are part of the 10-member catalytically active dual-specificity phosphatase (DUSP) family. RG0216 induced the expression of DUSP10, reduced the expression of DUSP4 and DUSP6, and decreased IL-6 and IL-8 expression in control and PgLPS-stimulated cultures. CONCLUSIONS: In HGK cells, a novel MAO-B inhibitor (RG0216) significantly altered DUSP4, DUSP6, and DUSP10 expression. DUSPs play a regulatory role in MAPK activity and, therefore, can alter cellular inflammatory responses. We found that RG0216 inhibited IL-6 and IL-8 expression. Further studies are planned to examine RG0216's regulatory role in DUSP expression and its impact on the regulation of cytokine/chemokine expression. [ABSTRACT FROM AUTHOR]

Aim: Porphyromonas gingivalis lipopolysaccharide (PgLPS) is a significant virulence factor and a driver of early innate immune responses in epithelial cells. The presence of PgLPS in immediate proximity to gingival epithelium induces significant inflammatory responses. In primary human gingival keratinocytes (HGK), we utilized transcriptome analysis to elucidate the change in early gene expression induced by PgLPS., Methods: HGK cell cultures were treated with PgLPS (4 h), and RNA was extracted and prepared for RNA sequence (RNAseq) analysis. Differentially expressed genes (DEGs) were identified, and potential interactions between these genes were subsequently examined using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analytic approaches to identify significantly enriched pathways. Expression of genes associated with relevant pathways was evaluated using real-time quantitative reverse-transcription polymerase chain reaction (RT-qPCR)., Results: RNAseq analysis identified 25 DEGs, and GO and KEGG analytic approaches showed related genes expressed in two general pathways. First, pathways broadly related to urokinase and coagulation included the genes PLAU, PLAUR, and SerpinB2. In RT-qPCR analysis, these genes were induced by PgLPS over time (4-24 h), and these data were consistent with PgLPS induction of cell migration. Second, interleukin-1 (IL-1) receptor binding and cytokine-activity pathways were also enriched. Genes associated with these pathways included IL36G, IL1B, IL1RN, and CXCL14. RT-qPCR analysis confirmed PgLPS induction of genes associated with the IL-1family. When expression of IL1B and IL36G genes was examined in relation to their respective antagonists, only IL36G gene expression was increased. CXCL14 gene expression was reduced over time, and this was consistent with RNAseq analysis., Conclusions: Genes associated with significantly enriched GO and KEGG pathways are relevant to aspects of periodontal disease (PDD) pathogenesis. First, PgLPS induced expression of PLAU, PLAUR, and SerpinB2, and these changes were consistent with an increase in cell migration that was found. Second, both IL36G and IL1B gene expression was significantly induced, but only IL36G in relation to its selective antagonist (IL36RN) was increased. These data support that early upregulation of IL36G may serve as an alarmin that can drive early innate immune inflammatory responses in HGK. Further in vivo testing of these findings is ongoing., (© 2024 The Author(s). Journal of Periodontal Research published by John Wiley & Sons Ltd.)