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Hama S, Nakahara M, Watanabe-Takahashi M, Shimizu E, Tsutsuki H, Yahiro K, Nishikawa K. Development of a novel tetravalent peptide that absorbs subtilase cytotoxin by targeting the receptor-binding B-subunit. Biochem Biophys Res Commun 2022; 629:95-100. [PMID: 36115284 DOI: 10.1016/j.bbrc.2022.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 08/26/2022] [Accepted: 09/02/2022] [Indexed: 11/30/2022]
Abstract
Subtilase cytotoxin (SubAB) is a major virulence factor produced by eae-negative Shiga-toxigenic Escherichia coli (STEC) that can cause fatal systemic complications. SubAB binds to target cells through multivalent interactions between its B-subunit pentamer and receptor molecules such as glycoproteins with a terminal N-glycolylneuraminic acid (Neu5Gc). We screened randomized multivalent peptide libraries synthesized on a cellulose membrane and identified a series of tetravalent peptides that efficiently bind to the receptor-binding region of the SubAB B-subunit pentamer. These peptides competitively inhibited the binding of the B-subunit to a receptor-mimic molecule containing clustered Neu5Gc (Neu5Gc-polymer). We selected the peptide with the highest inhibitory efficacy, FFP-tet, and covalently bound it to beads to synthesize FFP-tet-beads, a highly clustered SubAB absorber that displayed potency to absorb SubAB cytotoxicity through direct binding to the toxin. The efficacy of FFP-tet-beads to absorb SubAB cytotoxicity in solution was similar to that of Neu5Gc-polymer, suggesting that FFP-tet-beads might be an effective therapeutic agent against complications arising from eae-negative STEC infection.
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Affiliation(s)
- Shinichiro Hama
- Department of Molecular Life Sciences, Graduate School of Life and Medical Sciences, Doshisha University, Kyoto, 610-0321, Japan
| | - Miki Nakahara
- Department of Molecular Life Sciences, Graduate School of Life and Medical Sciences, Doshisha University, Kyoto, 610-0321, Japan
| | - Miho Watanabe-Takahashi
- Department of Molecular Life Sciences, Graduate School of Life and Medical Sciences, Doshisha University, Kyoto, 610-0321, Japan
| | - Eiko Shimizu
- Department of Molecular Life Sciences, Graduate School of Life and Medical Sciences, Doshisha University, Kyoto, 610-0321, Japan
| | - Hiroyasu Tsutsuki
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, 860-8556, Japan
| | - Kinnosuke Yahiro
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, 607-8414, Japan
| | - Kiyotaka Nishikawa
- Department of Molecular Life Sciences, Graduate School of Life and Medical Sciences, Doshisha University, Kyoto, 610-0321, Japan.
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Tsutsuki H, Zhang T, Yahiro K, Ono K, Fujiwara Y, Iyoda S, Wei FY, Monde K, Seto K, Ohnishi M, Oshiumi H, Akaike T, Sawa T. Subtilase cytotoxin from Shiga-toxigenic Escherichia coli impairs the inflammasome and exacerbates enteropathogenic bacterial infection. iScience 2022; 25:104050. [PMID: 35345462 PMCID: PMC8957020 DOI: 10.1016/j.isci.2022.104050] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/08/2022] [Accepted: 03/08/2022] [Indexed: 01/18/2023] Open
Abstract
Subtilase cytotoxin (SubAB) is an AB5 toxin mainly produced by the locus of enterocyte effacement-negative Shiga-toxigenic Escherichia coli (STEC) strain such as O113:H21, yet the contribution of SubAB to STEC infectious disease is unclear. We found that SubAB reduced activation of the STEC O113:H21 infection-induced non-canonical NLRP3 inflammasome and interleukin (IL)-1β and IL-18 production in murine macrophages. Downstream of lipopolysaccharide signaling, SubAB suppressed caspase-11 expression by inhibiting interferon-β/STAT1 signaling, followed by disrupting formation of the NLRP3/caspase-1 assembly. These inhibitions were regulated by PERK/IRE1α-dependent endoplasmic reticulum (ER) stress signaling initiated by cleavage of the host ER chaperone BiP by SubAB. Our murine model of SubAB-producing Citrobacter rodentium demonstrated that SubAB promoted C. rodentium proliferation and worsened symptoms such as intestinal hyperplasia and diarrhea. These findings highlight the inhibitory effect of SubAB on the NLRP3 inflammasome via ER stress, which may be associated with STEC survival and infectious disease pathogenicity in hosts. SubAB from STEC inhibits inflammasome activation and IL-1β/IL-18 production SubAB prevents caspase-11 expression via IRE1α/PERK-dependent inhibition of STAT1 SubAB reduces LPS-induced pro-IL-1β production via IRE1α/PERK-dependent pathway SubAB promotes C. rodentium survival in mouse colon and facilitates the infection
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Affiliation(s)
- Hiroyasu Tsutsuki
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
- Corresponding author
| | - Tianli Zhang
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Kinnosuke Yahiro
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan
| | - Katsuhiko Ono
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Yukio Fujiwara
- Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Chuo-ku, Kumamoto 860-8556, Japan
| | - Sunao Iyoda
- Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Fan-Yan Wei
- Department of Modomics Biology and Medicine, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Kazuaki Monde
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
| | - Kazuko Seto
- Quality Assurance Unit, Division of Planning, Osaka Institute of Public Health, 1-3-69 Nakamichi, Higashinari-ku, Osaka 537-0025, Japan
| | - Makoto Ohnishi
- Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Hiroyuki Oshiumi
- Department of Immunology, Graduate School of Medical Sciences, Kumamoto University, Chuo-ku, Kumamoto 860-8556, Japan
| | - Takaaki Akaike
- Department of Environmental Medicine and Molecular Toxicology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | - Tomohiro Sawa
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan
- Corresponding author
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Distribution of virulence factors, antimicrobial resistance genes and phylogenetic relatedness among Shiga toxin-producing Escherichia coli serogroup O91 from human infections. Int J Med Microbiol 2021; 311:151541. [PMID: 34757276 DOI: 10.1016/j.ijmm.2021.151541] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 10/10/2021] [Accepted: 10/25/2021] [Indexed: 12/18/2022] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) belonging to the serogroup O91 are among the most common non-O157 STEC serogroups associated with human illness in Europe. This study aimed to analyse the virulence factors, antimicrobial resistance genes and phylogenetic relatedness among 48 clinical STEC O91 isolates collected during 2003-2019 in Switzerland. The isolates were subjected to whole genome sequencing using short-read sequencing technologies and a subset of isolates additionally to long-read sequencing. They belonged to O91:H10 (n=6), O91:H14 (n=40), and O91:H21 (n=2). Multilocus sequence typing showed that the O91:H10 isolates all belonged to sequence type (ST)641, while the O91:H14 isolates were assigned to ST33, ST9700, or were non-typeable. Both O91:H21 isolates belonged to ST442. Shiga toxin gene stx1a was the most common Shiga toxin gene subtype among the isolates, followed by stx2b, stx2d and stx2a. All isolates were LEE-negative and carried one or two copies of the IrgA adhesin gene iha. In a subset of long-read sequenced isolates, modules of the Locus of Adhesion and Autoaggregation pathogenicity island (LAA-PAI) carrying iha and other genes such as hes, lesP or agn43 were identified. A large proportion of STEC O91:H14 carried the subtilase cytotoxin gene subA, colicin genes (cba, cea, cib and cma) or microcin genes (mcmA, mchB, mchC and mchF). STEC O91:H14 were further distinguished from STEC O91:H10/H21 by one or more virulence factors found in extraintestinal pathogenic E. coli (ExPEC), including hlyF, iucC/iutA, kpsE and traT. The hlyF gene was identified on a novel mosaic plasmid that was unrelated to hlyF+ plasmids described previously in STEC. Core genome phylogenetic analysis revealed that STEC O91:H10 and STEC O91:H21 were clonally conserved, whereas STEC O91:H14 were clonally diverse. Among three STEC O91:H14 isolates, a number of resistance genes were identified, including genes that mediate resistance to aminoglycosides (aadA, aadA2, aadA9, aadA23, aph(3'')-Ib and aph(6)-Id), chloramphenicol (cmlA), sulphonamides (sul2 and sul3), and trimethoprim (drfA12). Our data contribute to understanding the genetic diversity and differing levels of virulence potential within the STEC O91 serogroup.
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