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

Abstract

NLRP12 has been shown to play an essential role as a negative regulator in several bacterial infection. The purpose of this study is to elucidate the role of NLRP12 in B. pseudomallei-infected RAW264.7 macrophages. The protein expression and the level of TNF-α production were determined by immunoblotting and ELISA assay, respectively. 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. 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.