Vibrio cholerae OmpR Contributes to Virulence Repression and Fitness at Alkaline pH

Abstract

Vibrio cholerae is a Gram-negative human pathogen and the causative agent of the life-threatening disease cholera. V. cholerae is a natural inhabitant of marine environments and enters humans through the consumption of contaminated food or water. The ability to transition between aquatic ecosystems and the human host is paramount to the pathogenic success of V. cholerae. The transition between these two disparate environments requires the expression of adaptive responses, and such responses are most often regulated by two-component regulatory systems such as the EnvZ/OmpR system, which responds to osmolarity and acidic pH in many Gram-negative bacteria. Previous work in our laboratory indicated that V. cholerae OmpR functioned as a virulence regulator through repression of the LysR-family transcriptional regulator aphB; however, the role of OmpR in V. cholerae biology outside virulence regulation remained unknown. In this work, we sought to further investigate the function of OmpR in V. cholerae biology by defining the OmpR regulon through RNA sequencing. This led to the discovery that V. cholerae ompR was induced at alkaline pH to repress genes involved in acid tolerance and virulence factor production. In addition, OmpR was required for V. cholerae fitness during growth under alkaline conditions. These findings indicate that V. cholerae OmpR has evolved the ability to respond to novel signals during pathogenesis, which may play a role in the regulation of adaptive responses to aid in the transition between the human gastrointestinal tract and the marine ecosystem.

Evaluation of the occurrence of pathogenic free‐living amoeba and bacteria in 20 public indoor swimming pool facilities

“…was also found in the shower tap of one shower room (SP01F) and both footbaths analyzed (SP01H and SP16H) (Table 4). Several Vibrio species are pathogenic to humans producing several gastrointestinal disorders (Kunkle et al, 2020). Salmonella spp.…”

Crosstalks Between Gut Microbiota and Vibrio Cholerae

“…V. cholerae can also regulate lysine decarboxylase by AphB to consume H + so that it can alleviate low pH states (Kovacikova et al, 2010). Under alkaline conditions, V. cholerae can suppress related acid tolerance genes via OmpR and increase fitness (Kunkle et al, 2020). Indeed, V. cholerae itself has different pH patterns of fermentation depended on glucose.…”

Contribution of the EnvZ/OmpR two-component system to growth, virulence and stress tolerance of colistin-resistant Aeromonas hydrophila

“…The EnvZ/OmpR TCS is ubiquitous in gram-negative bacteria and regulates porin genes in response to changes in osmolarity, pH, and starvation ( Cai and Inouye, 2002 ; Yuan et al, 2011 ; Chhabra et al, 2012 ; Chakraborty and Kenney, 2018 ; Kenney, 2019 ; Gerken et al, 2020 ; Kunkle et al, 2020 ). In Escherichia coli , silencing of the EnvZ/OmpR TCS affects the expression of more than 100 genes, leading to changes in a variety of bacterial physiological properties, such as chemotaxis, adhesion, biofilm formation, stress tolerance, and even pathogenicity ( Oshima et al, 2002 ).…”

“…In Escherichia coli , silencing of the EnvZ/OmpR TCS affects the expression of more than 100 genes, leading to changes in a variety of bacterial physiological properties, such as chemotaxis, adhesion, biofilm formation, stress tolerance, and even pathogenicity ( Oshima et al, 2002 ). The EnvZ/OmpR TCS also controls virulence in other pathogens, including Shewanella oneidensis, Shigella flexneri , Yersinia pestis , and Vibrio cholerae ( Bernardini et al, 1990 ; Yuan et al, 2011 ; Reboul et al, 2014 ; Kunkle et al, 2020 ). In A. hydrophila , the EnvZ/OmpR two-component regulatory system has recently been reported to be involved in intracellular survival ( Du et al, 2022 ).…”