The catecholamine stress hormones norepinephrine and dopamine increase the virulence of pathogenic Vibrio anguillarum and Vibrio campbellii

Abstract

Obtaining a better understanding of mechanisms involved in bacterial infections is of paramount importance for the development of novel agents to control disease caused by (antibiotic resistant) pathogens in aquaculture. In this study, we investigated the impact of catecholamine stress hormones on growth and virulence factor production of pathogenic vibrios (i.e. two Vibrio campbellii strains and two Vibrio anguillarum strains). Both norepinephrine and dopamine (at 100 μM) significantly induced growth in media containing serum. The compounds also increased swimming motility of the tested strains, whereas they had no effect on caseinase, chitinase, and hemolysin activities. Further, antagonists for eukaryotic catecholamine receptors were able to neutralize some of the effects of the catecholamines. Indeed, the dopaminergic receptor antagonist chlorpromazine neutralized the effect of dopamine, and the α-adrenergic receptor antagonists phentolamine and phenoxybenzamine neutralized the effect of norepinephrine, whereas the β-adrenergic receptor antagonist propranolol had limited to no effect. Finally, pretreatment of pathogenic V. campbellii with catecholamines significantly increased its virulence toward giant freshwater prawn larvae. However, the impact of catecholamine receptor antagonists on in vivo virulence was less clear-cut when compared to the in vitro experiments. In summary, our results show that—similar to enteric pathogens—catecholamines also increase the virulence of vibrios that are pathogenic to aquatic organisms by increasing motility and growth in media containing serum.

Effect of catecholamine stress hormones (dopamine and norepinephrine) on growth, swimming motility, biofilm formation and virulence factors of Yersinia ruckeri in vitro and an in vivo evaluation in rainbow trout

“…The results from in vivo challenge assay demonstrated that pretreatment of Y. ruckeri with the catecholamines caused an increase in the virulence of the pathogen towards rainbow trout. Pande et al () also indicated that V. campbellii pretreated with norepinephrine and dopamine showed an increase in the virulence towards giant freshwater prawn larvae. Besides, the similar results obtained in another research revealed that the virulence of V. harveyi enhanced towards gnotobiotic brine shrimp larvae when was pretreated with the catecholamines.…”

“…On the other hand, our finding also suggests that the growth induced by norepinephrine in Y. ruckeri is mediated through a mechanism with α‐adrenergic specificity as only the α antagonists phenoxybenzamine and labetalol could block the adrenergic catecholamine‐induced growth. Similarly, it has been revealed that the response mechanisms for the catecholamines in enteric pathogens of terrestrial animals show a degree of specificity similar to mammalian catecholamine receptors (Freestone et al, ), V. campbellii and V. anguillarum (Pande et al, ) and Vibrio harveyi (Yang et al, ) . Previously, some pathogens (such as E. coli O157:H7, Salmonella, Eduardsiella tarda, Aggregatibacter actinomycetemcomitans, Actinobacillus pleuropneumoniae and Aeromonas hydrophila ) have been found to sense the host stress hormones through QseC and QseE (or their homologues) receptors, resulting in a complex regulatory cascade and then transcription of some virulence genes (Khajanchi, Kozlova, Sha, Popov, & Chopra, ; Li et al, ; Methner, Rabsch, Reissbrodt, & Williams, ; Novak, Shao, Daep, & Demuth, ; Sperandio, Torres, Jarvis, Nataro, & Kaper, ; Wang et al, ; Williams et al, ).…”

“…A pathogen encounters a new environment upon entrance into a host, and environmental changes trigger regulatory cascades that in turn influence gene expression (of virulence). Indeed, pathogens are able to detect the molecules produced by the host such as catecholamines, resulting in the production of virulence factors in bacteria (Alksne & Projan, ; Burton et al, ; Karavolos et al, ; Pande, Suong, Bossier, & Defoirdt, ; Yang et al, ).…”

“…turn influence gene expression (of virulence). Indeed, pathogens are able to detect the molecules produced by the host such as catecholamines, resulting in the production of virulence factors in bacteria (Alksne & Projan, 2000;Burton et al, 2002;Karavolos et al, 2008;Pande, Suong, Bossier, & Defoirdt, 2014;Yang et al, 2014).…”

Microbiome Disturbances and Autism Spectrum Disorders

“…Under culture conditions, NE and dopamine increase motility of various Vibrio strains (Pande et al, 2014). However, co-treatment with catecholamine receptor antagonists mitigated this effect.…”