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Chemello AJ, Fowler CC. Alternate typhoid toxin assembly evolved independently in the two Salmonella species. mBio 2024; 15:e0340323. [PMID: 38501873 PMCID: PMC11005416 DOI: 10.1128/mbio.03403-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/23/2024] [Indexed: 03/20/2024] Open
Abstract
AB5-type toxins are a diverse family of protein toxins composed of an enzymatic active (A) subunit and a pentameric delivery (B) subunit. Salmonella enterica serovar Typhi's typhoid toxin features two A subunits, CdtB and PltA, in complex with the B subunit PltB. Recently, it was shown that S. Typhi encodes a horizontally acquired B subunit, PltC, that also assembles with PltA/CdtB to produce a second form of typhoid toxin. S. Typhi therefore produces two AB5 toxins with the same A subunits but distinct B subunits, an evolutionary twist that is unique to typhoid toxin. Here, we show that, remarkably, the Salmonella bongori species independently evolved an analogous capacity to produce two typhoid toxins with distinct B subunits. S. bongori's alternate B subunit, PltD, is evolutionarily distant from both PltB and PltC and outcompetes PltB to form the predominant toxin. We show that, surprisingly, S. bongori elicits similar levels of CdtB-mediated intoxication as S. Typhi during infection of cultured human epithelial cells. This toxicity is exclusively due to the PltB toxin, and strains lacking pltD produce increased amounts of PltB toxin and exhibit increased toxicity compared to the wild type, suggesting that the acquisition of the PltD subunit potentially made S. bongori less virulent toward humans. Collectively, this study unveils a striking example of convergent evolution that highlights the importance of the poorly understood "two-toxin" paradigm for typhoid toxin biology and, more broadly, illustrates how the flexibility of A-B interactions has fueled the evolutionary diversification and expansion of AB5-type toxins. IMPORTANCE Typhoid toxin is an important Salmonella Typhi virulence factor and an attractive target for therapeutic interventions to combat typhoid fever. The recent discovery of a second version of this toxin has substantial implications for understanding S. Typhi pathogenesis and combating typhoid fever. In this study, we discover that a remarkably similar two-toxin paradigm evolved independently in Salmonella bongori, which strongly suggests that this is a critical aspect of typhoid toxin biology. We observe significant parallels between how the two toxins assemble and their capacity to intoxicate host cells during infection in S. Typhi and S. bongori, which provides clues to the biological significance of this unusual toxin arrangement. More broadly, AB5 toxins with diverse activities and mechanisms are essential virulence factors for numerous important bacterial pathogens. This study illustrates the capacity for novel A-B interactions to evolve and thus provides insight into how such a diverse arsenal of toxins might have emerged.
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Affiliation(s)
- Antonio J. Chemello
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Casey C. Fowler
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
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Park JY, Abekura F, Cho SH. GM1a ganglioside-binding domain peptide inhibits host adhesion and inflammatory response of enterotoxigenic Escherichia coli heat-labile enterotoxin-B in HCT-8 cells. Sci Rep 2023; 13:16835. [PMID: 37803175 PMCID: PMC10558473 DOI: 10.1038/s41598-023-44220-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 10/05/2023] [Indexed: 10/08/2023] Open
Abstract
Enterotoxigenic Escherichia coli (ETEC) is a major cause of illness and death but has no effective therapy. The heat-labile enterotoxin LT is a significant virulence factor produced by ETEC. The heat-labile enterotoxin-B (LT-B) subunit may enter host cells by binding to monosialotetrahexosylganglioside-a (GM1a), a monosialoganglioside found on the plasma membrane surface of animal epithelial cells. This research was conducted to develop conformationally comparable peptides to the carbohydrate epitope of GM1a for the treatment of ETEC. We used the LT-B subunit to select LT-B-binding peptides that structurally resemble GM1a. The ganglioside microarray and docking simulations were used to identify three GM1a ganglioside-binding domain (GBD) peptides based on LT-B recognition. Peptides had an inhibiting effect on the binding of LT-B to GM1a. The binding capacity, functional inhibitory activity, and in vitro effects of the GBD peptides were evaluated using HCT-8 cells, a human intestinal epithelial cell line, to evaluate the feasibility of deploying GBD peptides to combat bacterial infections. KILSYTESMAGKREMVIIT was the most efficient peptide in inhibiting cellular absorption of LT-B in cells. Our findings offer compelling evidence that GM1a GBD-like peptides might act as new therapeutics to inhibit LT-B binding to epithelial cells and avoid the subsequent physiological consequences of LT.
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Affiliation(s)
- Jun-Young Park
- Division of Zoonotic and Vector Borne Disease Research, Center for Infectious Disease Research, Korea National Institute of Health, Cheongju, Republic of Korea
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Fukushi Abekura
- Division of Zoonotic and Vector Borne Disease Research, Center for Infectious Disease Research, Korea National Institute of Health, Cheongju, Republic of Korea
| | - Seung-Hak Cho
- Division of Zoonotic and Vector Borne Disease Research, Center for Infectious Disease Research, Korea National Institute of Health, Cheongju, Republic of Korea.
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Sasmal A, Khan N, Khedri Z, Kellman BP, Srivastava S, Verhagen A, Yu H, Bruntse AB, Diaz S, Varki N, Beddoe T, Paton AW, Paton JC, Chen X, Lewis NE, Varki A. Simple and practical sialoglycan encoding system reveals vast diversity in nature and identifies a universal sialoglycan-recognizing probe derived from AB5 toxin B subunits. Glycobiology 2022; 32:1101-1115. [PMID: 36048714 PMCID: PMC9680115 DOI: 10.1093/glycob/cwac057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 08/20/2022] [Accepted: 08/23/2022] [Indexed: 01/07/2023] Open
Abstract
Vertebrate sialic acids (Sias) display much diversity in modifications, linkages, and underlying glycans. Slide microarrays allow high-throughput explorations of sialoglycan-protein interactions. A microarray presenting ~150 structurally defined sialyltrisaccharides with various Sias linkages and modifications still poses challenges in planning, data sorting, visualization, and analysis. To address these issues, we devised a simple 9-digit code for sialyltrisaccharides with terminal Sias and underlying two monosaccharides assigned from the nonreducing end, with 3 digits assigning a monosaccharide, its modifications, and linkage. Calculations based on the encoding system reveal >113,000 likely linear sialyltrisaccharides in nature. Notably, a biantennary N-glycan with 2 terminal sialyltrisaccharides could thus have >1010 potential combinations and a triantennary N-glycan with 3 terminal sequences, >1015 potential combinations. While all possibilities likely do not exist in nature, sialoglycans encode enormous diversity. While glycomic approaches are used to probe such diverse sialomes, naturally occurring bacterial AB5 toxin B subunits are simpler tools to track the dynamic sialome in biological systems. Sialoglycan microarray was utilized to compare sialoglycan-recognizing bacterial toxin B subunits. Unlike the poor correlation between B subunits and species phylogeny, there is stronger correlation with Sia-epitope preferences. Further supporting this pattern, we report a B subunit (YenB) from Yersinia enterocolitica (broad host range) recognizing almost all sialoglycans in the microarray, including 4-O-acetylated-Sias not recognized by a Yersinia pestis orthologue (YpeB). Differential Sia-binding patterns were also observed with phylogenetically related B subunits from Escherichia coli (SubB), Salmonella Typhi (PltB), Salmonella Typhimurium (ArtB), extra-intestinal E.coli (EcPltB), Vibrio cholera (CtxB), and cholera family homologue of E. coli (EcxB).
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Affiliation(s)
- Aniruddha Sasmal
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Naazneen Khan
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Zahra Khedri
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Benjamin P Kellman
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA
| | - Saurabh Srivastava
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Andrea Verhagen
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Hai Yu
- Department of Chemistry, University of California Davis, CA 95616, USA
| | - Anders Bech Bruntse
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA
| | - Sandra Diaz
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Nissi Varki
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Travis Beddoe
- Department of Animal, Plant and Soil Science and Centre for AgriBioscience, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Adrienne W Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005, Australia
| | - Xi Chen
- Department of Chemistry, University of California Davis, CA 95616, USA
| | - Nathan E Lewis
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093, USA
- Department of Pediatrics, University of California San Diego, La Jolla, CA 92093, USA
| | - Ajit Varki
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA 92093, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA 5005, Australia
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093, USA
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Srivastava S, Verhagen A, Sasmal A, Wasik BR, Diaz S, Yu H, Bensing BA, Khan N, Khedri Z, Secrest P, Sullam P, Varki N, Chen X, Parrish CR, Varki A. Development and applications of sialoglycan-recognizing probes (SGRPs) with defined specificities: exploring the dynamic mammalian sialoglycome. Glycobiology 2022; 32:1116-1136. [PMID: 35926090 PMCID: PMC9680117 DOI: 10.1093/glycob/cwac050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/20/2022] [Accepted: 07/14/2022] [Indexed: 01/07/2023] Open
Abstract
Glycans that are abundantly displayed on vertebrate cell surface and secreted molecules are often capped with terminal sialic acids (Sias). These diverse 9-carbon-backbone monosaccharides are involved in numerous intrinsic biological processes. They also interact with commensals and pathogens, while undergoing dynamic changes in time and space, often influenced by environmental conditions. However, most of this sialoglycan complexity and variation remains poorly characterized by conventional techniques, which often tend to destroy or overlook crucial aspects of Sia diversity and/or fail to elucidate native structures in biological systems, i.e. in the intact sialome. To date, in situ detection and analysis of sialoglycans has largely relied on the use of plant lectins, sialidases, or antibodies, whose preferences (with certain exceptions) are limited and/or uncertain. We took advantage of naturally evolved microbial molecules (bacterial adhesins, toxin subunits, and viral hemagglutinin-esterases) that recognize sialoglycans with defined specificity to delineate 9 classes of sialoglycan recognizing probes (SGRPs: SGRP1-SGRP9) that can be used to explore mammalian sialome changes in a simple and systematic manner, using techniques common in most laboratories. SGRP candidates with specificity defined by sialoglycan microarray studies were engineered as tagged probes, each with a corresponding nonbinding mutant probe as a simple and reliable negative control. The optimized panel of SGRPs can be used in methods commonly available in most bioscience labs, such as ELISA, western blot, flow cytometry, and histochemistry. To demonstrate the utility of this approach, we provide examples of sialoglycome differences in tissues from C57BL/6 wild-type mice and human-like Cmah-/- mice.
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Affiliation(s)
- Saurabh Srivastava
- Department of Cellular and Molecular Medicine, School of Medicine, University of California at San Diego, San Diego, CA, USA,Glycobiology Research and Training Center, University of California at San Diego, San Diego, CA, USA
| | - Andrea Verhagen
- Department of Cellular and Molecular Medicine, School of Medicine, University of California at San Diego, San Diego, CA, USA,Glycobiology Research and Training Center, University of California at San Diego, San Diego, CA, USA
| | - Aniruddha Sasmal
- Department of Cellular and Molecular Medicine, School of Medicine, University of California at San Diego, San Diego, CA, USA,Glycobiology Research and Training Center, University of California at San Diego, San Diego, CA, USA
| | - Brian R Wasik
- College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Sandra Diaz
- Department of Cellular and Molecular Medicine, School of Medicine, University of California at San Diego, San Diego, CA, USA,Glycobiology Research and Training Center, University of California at San Diego, San Diego, CA, USA
| | - Hai Yu
- Department of Chemistry, University of California at Davis, Davis, CA, USA
| | - Barbara A Bensing
- Department of Medicine, University of California, San Francisco, CA, USA,VA Medical Center, San Francisco, CA, USA
| | - Naazneen Khan
- Department of Cellular and Molecular Medicine, School of Medicine, University of California at San Diego, San Diego, CA, USA,Glycobiology Research and Training Center, University of California at San Diego, San Diego, CA, USA
| | - Zahra Khedri
- Department of Cellular and Molecular Medicine, School of Medicine, University of California at San Diego, San Diego, CA, USA,Glycobiology Research and Training Center, University of California at San Diego, San Diego, CA, USA
| | - Patrick Secrest
- Department of Cellular and Molecular Medicine, School of Medicine, University of California at San Diego, San Diego, CA, USA,Glycobiology Research and Training Center, University of California at San Diego, San Diego, CA, USA
| | - Paul Sullam
- Department of Medicine, University of California, San Francisco, CA, USA,VA Medical Center, San Francisco, CA, USA
| | - Nissi Varki
- Department of Cellular and Molecular Medicine, School of Medicine, University of California at San Diego, San Diego, CA, USA,Glycobiology Research and Training Center, University of California at San Diego, San Diego, CA, USA
| | - Xi Chen
- Department of Chemistry, University of California at Davis, Davis, CA, USA
| | - Colin R Parrish
- College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Ajit Varki
- Corresponding author: UCSD School of Medicine, La Jolla, CA 92093-0687, USA.
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Harada A, Tsutsuki H, Zhang T, Yahiro K, Sawa T, Niidome T. Controlled Delivery of an Anti-Inflammatory Toxin to Macrophages by Mutagenesis and Nanoparticle Modification. NANOMATERIALS 2022; 12:nano12132161. [PMID: 35807998 PMCID: PMC9268525 DOI: 10.3390/nano12132161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/20/2022] [Accepted: 06/20/2022] [Indexed: 02/05/2023]
Abstract
Advances in drug delivery systems (DDSs) have enabled the specific delivery of drugs to target cells. Subtilase cytotoxin (SubAB) produced by certain enterohemorrhagic Escherichia coli strains induces endoplasmic reticulum (ER) stress and suppresses nitric oxide generation in macrophages. We previously reported that modification of SubAB with poly(D,L-lactide-co-glycolic) acid (PLGA) nanoparticles (SubAB-PLGA NPs) increased intracellular uptake of SubAB and had an anti-inflammatory effect on macrophages. However, specific delivery of SubAB to macrophages could not be achieved because its effects on other cell types were not negligible. Therefore, to suppress non-specific SubAB binding, we used low-binding mutant SubABS35A (S35A) in which the 35th serine of the B subunit was mutated to alanine. In a macrophage cell line, PLGA NPs modified with S35A (S35A-PLGA NPs) induced ER stress and had anti-inflammatory effects similar to WT-PLGA NPs. However, in an epithelial cell line, S35A-PLGA NPs induced lower ER stress than WT-PLGA NPs. These results suggest that S35A is selectively delivered to macrophages rather than epithelial cells by modification with PLGA NPs and exerts anti-inflammatory effects. Our findings provide a useful technique for protein delivery to macrophages and encourage medical applications of DDSs for the treatment of inflammatory diseases.
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Affiliation(s)
- Ayaka Harada
- Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan;
| | - Hiroyasu Tsutsuki
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; (H.T.); (T.Z.); (T.S.)
| | - Tianli Zhang
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; (H.T.); (T.Z.); (T.S.)
| | - Kinnosuke Yahiro
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, 5 Misasagi-Nakauchi-cho, Yamashina-ku, Kyoto 607-8414, Japan;
| | - Tomohiro Sawa
- Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto 860-8556, Japan; (H.T.); (T.Z.); (T.S.)
| | - Takuro Niidome
- Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan;
- Correspondence:
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