| Title | Streptococcus pneumoniae aminopeptidase N contributes to bacterial virulence and elicits a strong innate immune response through MAPK and PI3K/AKT signaling |
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| Author | Ling Wang, Xuemei Zhang, Guangying Wu, Yuhong Qi, Jinghui Zhang, Jing Yang, Hong Wang, and Wenchun Xu* |
| Address | Key Laboratory of Clinical Laboratory Diagnostics Designated by the Ministry of Education, School of Laboratory Medicine, Chongqing Medical University, Chongqing, P. R. China |
| Bibliography | Journal of Microbiology, 58(4),330-339, 2020, |
| DOI | 10.1007/s12275-020-9538-0 |
| Key Words | Streptococcus pneumoniae, PepN, virulence, innate immunity, signaling pathway |
| Abstract | Streptococcus pneumoniae is a Gram-positive pathogen with high morbidity and mortality globally but some of its pathogenesis remains unknown. Previous research has provided evidence that aminopeptidase N (PepN) is most likely a virulence factor of S. pneumoniae. However, its role in S. pneumoniae virulence and its interaction with the host remains to be confirmed. We generated a pepN gene deficient mutant strain and found that its virulence for mice was significantly attenuated as were in vitro adhesion and invasion of host cells. The PepN protein could induce a strong innate immune response in vivo and in vitro and induced secretion of IL-6 and TNF-α by primary peritoneal macrophages via the rapid phosphorylation of MAPK and PI3K/AKT signaling pathways and this was confirmed using specific pathway inhibitors. In conclusion, PepN is a novel virulence factor that is essential for the virulence of S. pneumoniae and induces host innate immunity via MAPK and PI3K/AKT signaling. |