ATP and adenosine receptors modulate IL-1β secretion during Porphyromonas gingivalis infection

Authors

Cassio Luiz Coutinho Almeida-da-Silva, University of the PacificFollow
Erivan Schnaider Ramos-Junior, University of the Pacific
Ana Carolina Morandini, University of the PacificFollow
Brandon Triell Huynh, University of the Pacific
Angela Hwang, University of the Pacific
Ozge Carkan, University of the Pacific
Shijun Li, University of the Pacific
Ryan Park, University of the Pacific
David M. Ojcius, University of the PacificFollow
Robson Coutinho-Silva, Universidade Federal do Rio de Janeiro

Lead Author Program & Year

DDS Year 1

Introduction/Context/Diagnosis

Porphyromonas gingivalis (P. gingivalis) is a Gram-negative bacterium strongly associated with periodontitis. This pathogen induces pro- interleukin (IL)-1β synthesis by infected cells, but requires ligation of the P2X7 receptor by extracellular ATP (eATP) to trigger IL-1β release through NLRP3 inflammasome. We already demonstrated that eATP-induced IL- 1β secretion is impaired by P. gingivalis fimbriae via P2X7 receptor in macrophages. Here, we examined the effect of the activation of the purinergic signaling modulating IL-1β production during infection in macrophages.

Methods/Treatment Plan

Bone-marrow derived macrophages were obtained from C57BL/6 or P2X7^-/- mice and infected with P. gingivalis or P. gingivalis-nucleoside-diphosphate-kinase (NDK) deficient strain in an MOI of 100 for 6h, 18h and 24h. IL-1β production and secretion was detected by western blotting and ELISA. Antibiotic protection assay quantified bacterial invasion in macrophages. ATP secretion was measured using a bioluminescent reaction. Macrophage ectoenzymes activity was measured by pyrophosphate degradation using a colorimetric assay. Real-time PCR after 2h of infection was performed to analyze adenosine receptors expression.

Results/Outcome

We demonstrated P. gingivalis infection in macrophages requires eATP treatment and signaling via P2X7 receptor to promote IL-1β in 6h, 18h or 24h of infection. We showed P. gingivalis is able to induce pro-IL-1β production independently of P2X7 receptor in macrophages and that the pathogen infect wild-type and P2X7^-/- macrophages in similar levels. Next, we showed P. gingivalis induces ATP secretion from macrophages after infection and that P. gingivalis-NDK as long as macrophage ectoenzymes degrade eATP thus favoring production of extracellular adenosine. Adenosine potentiated eATP-induced IL-1β release in infected macrophages via adenosine receptors, probably via A_2A receptor.

Significance/Conclusions

Together, our data demonstrate that purinergic signaling via P2X7 and adenosine receptors modulates eATP-induced IL-1β secretion in P. gingivalis-infected macrophages.

Comments/Acknowledgements

This work was supported by FAPERJ scholarship to CLCAS, CNPq, and Funds from the Arthur Dugoni School of Dentistry.

Location

University of the Pacific, Dugoni Dental School, San Francisco, CA

Format

Poster

Poster Session

Faculty, Student, and Staff Presentations