Neisseria meningitidis pili induce type-IIA phospholipase A 2 expression in alveolar macrophages

Abstract

Induction of type-IIA secreted phospholipase A 2 (sPLA 2-IIA) expression by bacterial components other than lipopolysaccharide has not been previously investigated. Here, we show that exposure of alveolar macrophages (AM) to Neisseria meningitidis or its lipooligosaccharide (LOS) induced sPLA 2-IIA synthesis. However, N. meningitidis mutant devoid of LOS did not abolish this effect. In addition, a pili-defective mutant exhibited significantly lower capacity to stimulate sPLA 2-IIA synthesis than the wild-type strain. Moreover, pili isolated from a LOS-defective strain induced sPLA 2-IIA expression and nuclear factor kappa B (NF-κB) activation. These data suggest that pili are potent inducers of sPLA 2-IIA expression by AM, through a NF-κB-dependent process.