Identification and Characterization of the Neisseria gonorrhoeae MscS-Like Mechanosensitive Channel

Abstract

Mechanosensitive channels are ubiquitous in bacteria and provide an essential mechanism to survive sudden exposure to a hypo-osmotic environment by the sensing and release of increased turgor pressure. No mechanosensitive channels have thus far been identified and characterized for the human-specific bacterial pathogen In this study, we identified and characterized the MscS-like mechanosensitive channel (Ng-MscS). Electrophysiological analyses by the patch clamp method showed that Ng-MscS is stretch activated and contains pressure-dependent gating properties. Further mutagenesis studies of critical residues forming the hydrophobic vapor lock showed that gain-of-function mutations in Ng-MscS inhibited bacterial growth. Subsequent analysis of the function of Ng-MscS in by osmotic down-shock assays revealed that the survival of Ng- deletion mutants was significantly reduced compared with that of wild-type strains, while down-shock survival was restored upon the ectopic complementation of Finally, to investigate whether Ng-MscS is important for during infections, competition assays were performed by using a murine vaginal tract infection model. Ng- deletion mutants were outcompeted by wild-type strains for colonization and survival in this infection model, highlighting that Ng-MscS contributes to colonization and survival. Therefore, Ng-MscS might be a promising target for the future development of novel antimicrobials.

Roles of Bacterial Mechanosensitive Channels in Infection and Antibiotic Susceptibility

“…Yet, considering that the osmolarity of urine can decrease rapidly and considerably, e.g., by imbibing a large amount of water, it is reasonable to assume that mechanosensitive channels may play a role in this environment as well. This notion is supported by the apparent importance of Ng-MscS in N. gonorrhoeae colonization of the urogenital tract [ 15 ] and will be an interesting subject for future research.…”

“…In some cases, mechanosensitive channels play a role in transitioning from the environment to the host and enable bacteria to colonize host tissues [ 14 , 15 , 17 ]. One example for this is Salmonella typhimurium .…”

“…During infection, N. gonorrhoeae may experience fluctuating osmotic conditions, e.g., during the passing of urine. An MscS-like channel (Ng-MscS) has been shown to be essential for osmotic downshock survival in this organism, and the N. gonorrhoeae wild type outcompeted a mutant lacking this channel, with respect to colonization and survival, in a murine vaginal-tract-infection model, putting forward the importance of Ng-MscS in host colonization [ 15 ].…”

“…Bacterial Mechanosensitive channels are often viewed from an environmental or biotechnological perspective, e.g., enhanced glutamate secretion in the industrial amino-acid producer Corynebacterium glutamicum . Yet, they have also been reported to play a role in bacterial pathogenesis [ 13 , 14 , 15 , 16 , 17 ] and appear to be of importance for the susceptibility of different bacterial species to antimicrobials [ 18 , 19 , 20 ]. Interestingly, some studies have shown that mechanosensitive channels increase the potency of certain antibiotics, by serving as their entry gates into bacterial cells [ 19 , 20 ], while others have observed that bacteria adapt to antibiotic-induced membrane stress by opening mechanosensitive channels that contribute to antibiotic tolerance [ 11 , 21 ].…”

Impact of the gonococcal FC428 penA allele 60.001 on ceftriaxone resistance and biological fitness

“…The chloramphenicol-resistant derivatives SZ20- penA 60- catA2 , SZ20- penA 10- catA2 , SRRSH78- penA 10- catA2 , and SRRSH78- penA 60- catA2 were generated with the vector pUC57- lctP-catA2-aspC [ 41 ], which inserts the chloramphenicol-resistant gene catA2 in the unrelated convergent lctP - aspC locus. The kanamycin-resistant derivatives SZ20- penA 60- kanR , SZ20- penA 10- kanR , SRRSH78- penA 10- kanR , and SRRSH78- penA 60- kanR were generated with the vector pUC57- lctP-kanR-aspC [ 42 ], which inserts the kanamycin-resistant gene kanR in the ctP - aspC locus.…”