Stephan P. Ebenberger, Fatih Cakar, Yi-Chi Chen, Katharina Pressler, Leo Eberl, Stefan Schild
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引用次数: 0
Abstract
Vibrio cholerae, a facultative human pathogen and causative agent of the severe diarrheal disease cholera, transits between the human intestinal tract and aquatic reservoirs. Like other bacterial species, V. cholerae continuously releases bacterial extracellular vesicles (BEVs) from its surface, which have been recently characterised for their role during in vivo colonisation. However, between epidemic outbreaks, V. cholerae persists in the biofilm mode for extended periods in aquatic reservoirs, which enhances environmental fitness and host transition. In this study, we investigated the effect of V. cholerae BEVs on biofilm formation, a critical feature for ex vivo survival. In contrast to BEVs from planktonic cultures, our results show that physiological concentrations of BEVs from dynamic biofilm cultures facilitate V. cholerae biofilm formation, which could be linked to a proteinaceous factor. Comparative proteomic analyses of planktonic- and biofilm-derived BEVs identified a previously uncharacterised outer membrane protein as an abundant component of dynamic biofilm-derived BEVs, which was found to be responsible for the BEV-dependent enhancement of biofilm production. Consequently, this protein was named outer membrane-associated biofilm facilitating protein A (ObfA). Comprehensive molecular studies unravelled ObfA as a negative modulator of HapR activity. HapR is a key transcriptional regulator of the V. cholerae quorum sensing (QS) cascade acting as a potent repressor of biofilm formation and virulence. Consistently, obfA mutants not only exhibited reduced biofilm production but also reduced colonisation fitness. Surprisingly, our results demonstrate that ObfA does not affect HapR through the canonical QS system but via the Csr-cascade altering the expression of the small regulatory RNAs CsrC and CsrD. In summary, this study elucidates a novel intraspecies BEV-based communication in V. cholerae that influences biofilm formation and colonisation fitness via a new regulatory pathway involving HapR, Csr-cascade and the BEV-associated protein ObfA.
期刊介绍:
The Journal of Extracellular Vesicles is an open access research publication that focuses on extracellular vesicles, including microvesicles, exosomes, ectosomes, and apoptotic bodies. It serves as the official journal of the International Society for Extracellular Vesicles and aims to facilitate the exchange of data, ideas, and information pertaining to the chemistry, biology, and applications of extracellular vesicles. The journal covers various aspects such as the cellular and molecular mechanisms of extracellular vesicles biogenesis, technological advancements in their isolation, quantification, and characterization, the role and function of extracellular vesicles in biology, stem cell-derived extracellular vesicles and their biology, as well as the application of extracellular vesicles for pharmacological, immunological, or genetic therapies.
The Journal of Extracellular Vesicles is widely recognized and indexed by numerous services, including Biological Abstracts, BIOSIS Previews, Chemical Abstracts Service (CAS), Current Contents/Life Sciences, Directory of Open Access Journals (DOAJ), Journal Citation Reports/Science Edition, Google Scholar, ProQuest Natural Science Collection, ProQuest SciTech Collection, SciTech Premium Collection, PubMed Central/PubMed, Science Citation Index Expanded, ScienceOpen, and Scopus.