Soluble epoxide hydrolase inhibition impairs triggering receptor expressed on myeloid cells-1 in periodontal tissue

Breno da Silva Vargas; Bruno Sérgio Ferreira Vargas; Juliana Trindade Clemente-Napimoga; Bruce D Hammock; Henrique B Abdalla; Thomas E Van Dyke; Marcelo H Napimoga

doi:10.1111/jre.13350

Soluble epoxide hydrolase inhibition impairs triggering receptor expressed on myeloid cells-1 in periodontal tissue

J Periodontal Res. 2024 Sep 29. doi: 10.1111/jre.13350. Online ahead of print.

Authors

Breno da Silva Vargas¹, Bruno Sérgio Ferreira Vargas¹, Juliana Trindade Clemente-Napimoga¹, Bruce D Hammock², Henrique B Abdalla¹, Thomas E Van Dyke^{3

4}, Marcelo H Napimoga¹

Affiliations

¹ Laboratory of Neuroimmune Interface of Pain Research, Faculdade São Leopoldo Mandic, Instituto de Pesquisa São Leopoldo Mandic, Campinas, Brazil.
² Department of Entomology and UCD Comprehensive Cancer Center, University of California, Davis, California, USA.
³ Department of Immunology and Inflammation, The ADA Forsyth Institute, Cambridge, Massachusetts, USA.
⁴ Department of Oral Medicine, Infection, and Immunity, Faculty of Medicine, Harvard University, Boston, Massachusetts, USA.

PMID: 39343738
DOI: 10.1111/jre.13350

Abstract

Aims: Periodontitis is a prevalent inflammatory disorder affecting the oral cavity, driven by dysbiotic oral biofilm and host immune response interactions. While the major clinical focus of periodontitis treatment is currently controlling oral biofilm, understanding the immune response is crucial to prevent disease progression. Soluble epoxide hydrolase (sEH) inhibition has shown promise in preventing alveolar bone resorption. Triggering receptors expressed on myeloid cells (TREMs) play pivotal roles in regulating inflammation and bone homeostasis, and dysregulation of TREM signaling is implicated in periodontitis. Here, we investigated the impact of sEH inhibition on TREM 1 and 2 expression, associated with inflammatory cytokines, and histologically assessed the inflammatory infiltrate in periodontal tissue.

Methods: The experimental periodontitis model was induced by placing a ligature around the upper second molar. For 14 days, animals were treated daily with a sEH inhibitor (TPPU) or vehicle. The alveolar bone loss was examined using a methylene blue stain. Gingival tissues were used to measure the mRNA expression of TREM-1, TREM-2, IKKβ, NF-κB, IL-1β, IL-6, IL-8, and TNF-α by RT-qPCR. Another set of experiments was performed to determine the histological inflammatory scores.

Results: In a ligature-induced periodontitis model, sEH inhibition prevented alveolar bone loss and reduced TREM1 expression, albeit with a slight elevation compared to the disease-free group. In contrast, TREM2 expression remained elevated, suggesting sustained immunomodulation favoring resolution. The inhibition of sEH reduced the expression of NF-κB, IL-1β, and TNF-α, while no differences were found in the expression of IL-6, IL-8, and IKKβ. In histological analysis, sEH inhibition reduced the inflammatory leukocyte infiltrate in periodontal tissues close to the ligature.

Conclusion: These findings underscore the potential of sEH inhibition to modulate periodontal inflammation by regulating TREM-1 alongside decreased IL-1β and TNF-α expression, highlighting a promising therapeutic approach for periodontitis management.

Keywords: bone; inflammation; periodontitis; soluble epoxide hydrolase; triggering receptors expressed on myeloid cells.

Abstract

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