NLRP12 attenuates tumor necrosis factor-α production in Burkholderia pseudomallei-infected RAW264.7 macrophages

Matsayapan Pudla,¹ Poramed Onsoi,¹ Pongsak Utaisincharoen²

¹ Department of Oral Microbiology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
² Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand

Abstract

Background: NLRP12 has been shown to play an essential role as a negative regulator in several bacterial infection.
Objective: The purpose of this study is to elucidate the role of NLRP12 in B. pseudomallei-infected RAW264.7 macrophages.
Methods: The protein expression and the level of TNF-α production were determined by immunoblotting and ELISA assay, respectively.
Results: The results demonstrated that unlike the LPS-mutant strain which lacks O antigenic polysaccharide, the wild-type B. pseudomallei was able to upregulate NLRP12 protein expression in RAW264.7 macrophages. NLRP12 expression also correlated with the suppression of TNF-α production as demonstrated in wild-type B. pseudomallei-infected Nlrp12-depleted macrophages when compared to that of the control siRNA-transfected cells. The expression of NLRP12 was also inhibited in cytochalasin D treated cells.
Conclusion: Our findings showed that wild-type B. pseudomallei can activate NLRP12 expression leading to the suppression of TNF-α production. It is possible that the regulation of NLRP12 may contribute to the pathogenesis of B. pseudomallei infection in melioidosis patients.
Key words: Burkholderia pseudomallei, mouse macrophage, NLRP12, RAW264.7, TNF-α