期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 100, 期 15, 页码 8951-8956出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1537100100
关键词
enterohemorrhagic Escherichia coli; quorum sensing; type III secretion; epinephrine
资金
- NIAID NIH HHS [R37 AI021657, R01 AI021657, AI41325, AI21657] Funding Source: Medline
The interbacterial communication system known as quorum sensing (QS) utilizes hormone-like compounds referred to as autoinducers to regulate bacterial gene expression. Enterohemorrhagic Escherichia coli (EHEC serotype O157:H7 is the agent responsible for outbreaks of bloody diarrhea in several countries. We previously proposed that EHEC uses a QS regulatory system to sense that it is within the intestine and activate genes essential for intestinal colonization. The QS system used by EHEC is the LuxS/ autoinducer 2 (Al-2) system extensively involved in interspecies communication. The autoinducer AI-2 is a furanosyl borate diester whose synthesis depends on the enzyme LuxS. Here we show that an EHEC luxS mutant, unable to produce the bacterial autoinducer, still responds to a eukaryotic cell signal to activate expression of its virulence genes. We have identified this signal as the hormone epinephrine and show that beta- and alpha-adrenergic antagonists can block the bacterial response to this hormone. Furthermore, using purified and in vitro synthesized Al-2 we showed that AI-2 is not the autoinducer involved in the bacterial signaling. EHEC produces another, previously undescribed autoinducer (Al-3) whose synthesis depends on the presence of LuxS. These results imply a potential cross-communication between the luxS/Al-3 bacterial QS system and the epinephrine host signaling system. Given that eukaryotic cell-to-cell signaling typically occurs through hormones, and that bacterial cell-to-cell signaling occurs through QS, we speculate that QS might be a language by which bacteria and host cells communicate.
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