Biology:Enterohemolysin
Enterohemolysin, also known as EHEC-Hly or Ehx, is a bacterial toxin and a significant virulence factor produced by enterohemorrhagic Escherichia coli (EHEC).[1][2] It belongs to the Repeats-in-Toxin (RTX) family of pore-forming proteins. The genetic instructions for producing enterohemolysin are located on a large plasmid within the bacteria in an operon designated EHEC-hlyCABD.[1]
This toxin plays a role in the tissue damage observed during EHEC infections, which can lead to severe illnesses such as hemorrhagic colitis and hemolytic-uremic syndrome (HUS).[2] Enterohemolysin exists in two biologically active forms: a free, soluble form and another form associated with outer membrane vesicles (OMVs) released by the bacteria.[1] The OMV-associated form is more stable and has a prolonged hemolytic effect compared to the free toxin.[3] The free form of EHEC-Hly lyses human microvascular endothelial cells by creating pores in the cell membrane. In contrast, the OMV-associated form does not lyse these cells but instead enters them, targets the mitochondria, and induces programmed cell death (apoptosis).[4] Furthermore, EHEC-Hly can stimulate an inflammatory response by prompting human monocytes and macrophages to release interleukin-1β.[5][6]
See also
References
- ↑ 1.0 1.1 1.2 "Hemolysin of enterohemorrhagic Escherichia coli: structure, transport, biological activity and putative role in virulence". Int J Med Microbiol 304 (5–6): 521–9. July 2014. doi:10.1016/j.ijmm.2014.05.005. PMID 24933303.
- ↑ 2.0 2.1 "Genetics, Toxicity, and Distribution of Enterohemorrhagic Escherichia coli Hemolysin". Toxins (Basel) 11 (9): 502. August 2019. doi:10.3390/toxins11090502. PMID 31470552.
- ↑ "Vesicular stabilization and activity augmentation of enterohaemorrhagic Escherichia coli haemolysin". Mol Microbiol 71 (6): 1496–508. March 2009. doi:10.1111/j.1365-2958.2009.06618.x. PMID 19210618.
- ↑ "Enterohemorrhagic Escherichia coli hemolysin employs outer membrane vesicles to target mitochondria and cause endothelial and epithelial apoptosis". PLOS Pathog 9 (12). 2013. doi:10.1371/journal.ppat.1003797. PMID 24348251.
- ↑ "Enterohemolysin operon of Shiga toxin-producing Escherichia coli: a virulence function of inflammatory cytokine production from human monocytes". FEBS Lett 524 (1–3): 219–24. July 2002. doi:10.1016/s0014-5793(02)03027-2. PMID 12135770. Bibcode: 2002FEBSL.524..219T.
- ↑ "Enterohemorrhagic Escherichia coli specific enterohemolysin induced IL-1β in human macrophages and EHEC-induced IL-1β required activation of NLRP3 inflammasome". PLOS ONE 7 (11). 2012. doi:10.1371/journal.pone.0050288. PMID 23209696. Bibcode: 2012PLoSO...750288Z.
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