AUTHOR=Li Huan , Liu Feng , Peng Wei , Yan Kang , Zhao Haixu , Liu Ting , Cheng Hui , Chang Peixi , Yuan Fangyan , Chen Huanchun , Bei Weicheng 

TITLE=The CpxA/CpxR Two-Component System Affects Biofilm Formation and Virulence in Actinobacillus pleuropneumoniae

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=8

YEAR=2018

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2018.00072

DOI=10.3389/fcimb.2018.00072

ISSN=2235-2988

ABSTRACT=<p>Gram-negative bacteria have evolved numerous two-component systems (TCSs) to cope with external environmental changes. The CpxA/CpxR TCS consisting of the kinase CpxA and the regulator CpxR, is known to be involved in the biofilm formation and virulence of <italic>Escherichia coli</italic>. However, the role of CpxA/CpxR remained unclear in <italic>Actinobacillus pleuropneumoniae</italic>, a bacterial pathogen that can cause porcine contagious pleuropneumonia (PCP). In this report, we show that CpxA/CpxR contributes to the biofilm formation ability of <italic>A. pleuropneumoniae</italic>. Furthermore, we demonstrate that CpxA/CpxR plays an important role in the expression of several biofilm-related genes in <italic>A. pleuropneumoniae</italic>, such as <italic>rpoE</italic> and <italic>pgaC</italic>. Furthermore, The results of electrophoretic mobility shift assays (EMSAs) and DNase I footprinting analysis demonstrate that CpxR-P can regulate the expression of the <italic>pgaABCD</italic> operon through <italic>rpoE</italic>. In an experimental infection of mice, the animals infected with a <italic>cpxA/cpxR</italic> mutant exhibited delayed mortality and lower bacterial loads in the lung than those infected with the wildtype bacteria. In conclusion, these results indicate that the CpxA/CpxR TCS plays a contributing role in the biofilm formation and virulence of <italic>A. pleuropneumoniae</italic>.</p>