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Cao Y, Bai Y, Li H, Ma B, Zhang W. Preparation and evaluation of recombinant pyolysin, fimbriae E and HtaA based protein vaccines against Trueperella pyogenes. Vet Microbiol 2023; 284:109810. [PMID: 37307768 DOI: 10.1016/j.vetmic.2023.109810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/14/2023]
Abstract
Trueperella pyogenes (T. pyogenes) could cause zoonotic disease in various mammals, resulting in significant economic losses. Due to the lack of effective vaccine and the emergence of bacterial resistance, there is a big need for new and improved vaccines. In this study, the non-hemolytic pyolysin mutant (PLOW497F), fimbriae E (FimE) and a truncated cell wall protein (HtaA-2) were selected to generate single or multivalent protein vaccines and their efficacies against lethal T. pyogenes challenge were evaluated in a mouse model. The results showed that the levels of specific antibody were significantly higher than the PBS control group after the booster vaccination. Compared to PBS treated mice, vaccinated mice had upregulated expressions of the inflammatory cytokine genes after the first vaccination. There was a downward trend thereafter, but return to the similar or even higher levels after challenge. Furthermore, co-immunization with rFimE or rHtaA-2 could significantly enhance the anti-hemolysis antibodies induced by rPLOW497F. The supplement of rHtaA-2 induced higher agglutinating antibodies compared with single administration with rPLOW497F or rFimE. Apart from these, the pathological lesions of lung were alleviated in rHtaA-2, rPLOW497F or their combinations immunized mice. Notably, immunization with rPLOW497F, rHtaA-2, combinations of rPLOW497F and rHtaA-2 or rHtaA-2 and rFimE completely protected mice from challenge, whereas the PBS immunized mice could not survive past 1 day post challenge. Thus, PLOW497F and HtaA-2 might be useful in developing efficient vaccines to prevent T. pyogenes infection.
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Affiliation(s)
- Yongsheng Cao
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Changjiang Street NO.600, Harbin, China; Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China.
| | - Yunlu Bai
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Changjiang Street NO.600, Harbin, China; Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
| | - Hanqing Li
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Changjiang Street NO.600, Harbin, China; Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
| | - Bo Ma
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Changjiang Street NO.600, Harbin, China; Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
| | - Wenlong Zhang
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Changjiang Street NO.600, Harbin, China; Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China.
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Liang H, Wang B, Wang J, Ma B, Zhang W. Pyolysin of Trueperella pyogenes Induces Pyroptosis and IL-1β Release in Murine Macrophages Through Potassium/NLRP3/Caspase-1/Gasdermin D Pathway. Front Immunol 2022; 13:832458. [PMID: 35371034 PMCID: PMC8965163 DOI: 10.3389/fimmu.2022.832458] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/23/2022] [Indexed: 11/13/2022] Open
Abstract
Trueperella pyogenes (T. pyogenes) is a commensal and an opportunistic pathogen of animals. This organism can cause inflammatory diseases, such as pneumonia, mastitis and endometritis in hosts. However, the molecular basis for the pro-inflammatory properties of this organism is still largely unknown. In the current study, using murine macrophages as model, the ability of T. pyogenes to induce pyroptosis was first determined. Then, pyolysin (PLO), a cholesterol-dependent cytolysin secreted by T. pyogenes, was found to be closely related to T. pyogenes-induced pyroptosis. Next, our work showed that PLO can form pores in the cell membrane, leading to the efflux of potassium (K+), NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediated caspase-1 activation, and gasdermin D (GSDMD) cleavage. Inhibition of the K+/NLRP3/caspase-1/GSDMD pathway abolished T. pyogenes and PLO-induced IL-1β release. Taken together, these results indicate T. pyogenes-induced inflammation is related to PLO-induced pyroptosis and IL-1β release. Our work shed light on the pathogenesis of T. pyogenes and the interaction between T. pyogenes and hosts' immune system.
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Affiliation(s)
- Hongmin Liang
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
| | - Bing Wang
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
| | - Junwei Wang
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
| | - Bo Ma
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
| | - Wenlong Zhang
- Laboratory of Veterinary Immunology, Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.,Northeastern Science Inspection Station, China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology, Harbin, China
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Zhang W, Wang H, Wang B, Zhang Y, Hu Y, Ma B, Wang J. Replacing the 238th aspartic acid with an arginine impaired the oligomerization activity and inflammation-inducing property of pyolysin. Virulence 2018; 9:1112-1125. [PMID: 30067143 PMCID: PMC6086297 DOI: 10.1080/21505594.2018.1491256] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Trueperella pyogenes (T. pyogenes) is an important opportunistic pathogen. Pyolysin (PLO) importantly contributes to the pathogenicity of T. pyogenes. However, the relationship between the structure and function and the virulence of PLO is not well documented. In the current study, recombinant PLO (rPLO) and three rPLO mutants were prepared. rPLO D238R, a mutant with the 238th aspartic acid replaced with an arginine, showed impairment in oligomerization activity on cholesterol-containing liposome and pore-forming activity on sheep red blood cell membrane. Further study employing the prepared mutants confirmed that the pore-forming activity of PLO is essential for inducing excessive inflammation responses in mice by upregulating the expression levels of IL-1β, TNF-α, and IL-6. By contrast, rPLO P499F, another mutant with impaired cell membrane binding capacity, elicited an inflammation response that was dependent on pathogen-associated molecular pattern (PAMP) activity, given that the mutant significantly upregulated the expression of IL-10 in macrophages and in mice, whereas rPLO did not. Results indicated that domain 1 of the PLO molecule plays an important role in maintaining pore-forming activity. Moreover, the PLO pore-forming activity and not PAMP activity is responsible for the inflammation-inducing effect of PLO. The results of this study provided new information for research field on the structure, function, and virulence of PLO. Abbreviations: T. pyogenes: Trueperella pyogenes; PLO: Pyolysin; rPLO: recombinant PLO; PAMP: pathogen-associated molecular pattern; CDCs: cholesterol-dependent cytolysins; PLY: pneumolysin; NLRP3: NLR family pyrin domain containing protein 3; PRRs: pattern recognition receptors; Asp: aspartic acid; TLR4: Toll-like receptor 4; Arg: arginine; Asn: asparagine; IPTG: Isopropyl-β-d-thiogalactoside; PBS: phosphate-buffered saline; sRBCs: sheep red blood cells; TEM: Transmission electron microscopy; RBCM: red blood cell membrane; SDS-PAGE: sodium dodecyl sulfate–polyacrylamide gel electrophoresis; NC membrane: nitrocellulose membrane; SDS-AGE: dodecyl sulfate agarose gel electrophoresis; MDBK cells: Madin–Darby bovine kidney cells; RPMI-1640 medium: Roswell Park Memorial Institute-1640 medium; FBS: fetal bovine serum; BMDMs: bone marrow-derived macrophages; TNF-α: tumor necrosis factor α; IL-1β: interleukin-1β; IFN-γ: interferon-γ; TGF-β: transforming growth factor-β; ELISA: enzyme-linked immunosorbent assay
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Affiliation(s)
- Wenlong Zhang
- a College of Veterinary Medicine , Northeast Agricultural University , Harbin , PR China.,b China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology , Northeastern Science Inspection Station , Harbin , PR China
| | - Haili Wang
- a College of Veterinary Medicine , Northeast Agricultural University , Harbin , PR China.,b China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology , Northeastern Science Inspection Station , Harbin , PR China
| | - Bing Wang
- a College of Veterinary Medicine , Northeast Agricultural University , Harbin , PR China.,b China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology , Northeastern Science Inspection Station , Harbin , PR China
| | - Yue Zhang
- a College of Veterinary Medicine , Northeast Agricultural University , Harbin , PR China.,b China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology , Northeastern Science Inspection Station , Harbin , PR China
| | - Yunhao Hu
- a College of Veterinary Medicine , Northeast Agricultural University , Harbin , PR China.,b China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology , Northeastern Science Inspection Station , Harbin , PR China
| | - Bo Ma
- a College of Veterinary Medicine , Northeast Agricultural University , Harbin , PR China.,b China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology , Northeastern Science Inspection Station , Harbin , PR China
| | - Junwei Wang
- a College of Veterinary Medicine , Northeast Agricultural University , Harbin , PR China.,b China Ministry of Agriculture Key Laboratory of Animal Pathogen Biology , Northeastern Science Inspection Station , Harbin , PR China
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Griffin S, Preta G, Sheldon IM. Inhibiting mevalonate pathway enzymes increases stromal cell resilience to a cholesterol-dependent cytolysin. Sci Rep 2017; 7:17050. [PMID: 29213055 PMCID: PMC5719056 DOI: 10.1038/s41598-017-17138-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 11/22/2017] [Indexed: 01/28/2023] Open
Abstract
Animal health depends on the ability of immune cells to kill invading pathogens, and on the resilience of tissues to tolerate the presence of pathogens. Trueperella pyogenes causes tissue pathology in many mammals by secreting a cholesterol-dependent cytolysin, pyolysin (PLO), which targets stromal cells. Cellular cholesterol is derived from squalene, which is synthesized via the mevalonate pathway enzymes, including HMGCR, FDPS and FDFT1. The present study tested the hypothesis that inhibiting enzymes in the mevalonate pathway to reduce cellular cholesterol increases the resilience of stromal cells to PLO. We first verified that depleting cellular cholesterol with methyl-β-cyclodextrin increased the resilience of stromal cells to PLO. We then used siRNA to deplete mevalonate pathway enzyme gene expression, and used pharmaceutical inhibitors, atorvastatin, alendronate or zaragozic acid to inhibit the activity of HMGCR, FDPS and FDFT1, respectively. These approaches successfully reduced cellular cholesterol abundance, but mevalonate pathway enzymes did not affect cellular resilience equally. Inhibiting FDFT1 was most effective, with zaragozic acid reducing the impact of PLO on cell viability. The present study provides evidence that inhibiting FDFT1 increases stromal cell resilience to a cholesterol-dependent cytolysin.
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Affiliation(s)
- Sholeem Griffin
- Swansea University Medical School, Swansea University, Swansea, SA2 8PP, United Kingdom
| | - Giulio Preta
- Swansea University Medical School, Swansea University, Swansea, SA2 8PP, United Kingdom.,Institute of Biochemistry, Vilnius University, Sauletekio 7, Vilnius LT-10257, Lithuania
| | - Iain Martin Sheldon
- Swansea University Medical School, Swansea University, Swansea, SA2 8PP, United Kingdom.
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Interaction of Cholesterol with Perfringolysin O: What Have We Learned from Functional Analysis? Toxins (Basel) 2017; 9:toxins9120381. [PMID: 29168745 PMCID: PMC5744101 DOI: 10.3390/toxins9120381] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 11/16/2017] [Accepted: 11/17/2017] [Indexed: 12/27/2022] Open
Abstract
Cholesterol-dependent cytolysins (CDCs) constitute a family of pore-forming toxins secreted by Gram-positive bacteria. These toxins form transmembrane pores by inserting a large β-barrel into cholesterol-containing membranes. Cholesterol is absolutely required for pore-formation. For most CDCs, binding to cholesterol triggers conformational changes that lead to oligomerization and end in pore-formation. Perfringolysin O (PFO), secreted by Clostridium perfringens, is the prototype for the CDCs. The molecular mechanisms by which cholesterol regulates the cytolytic activity of the CDCs are not fully understood. In particular, the location of the binding site for cholesterol has remained elusive. We have summarized here the current body of knowledge on the CDCs-cholesterol interaction, with focus on PFO. We have employed sterols in aqueous solution to identify structural elements in the cholesterol molecule that are critical for its interaction with PFO. In the absence of high-resolution structural information, site-directed mutagenesis data combined with binding studies performed with different sterols, and molecular modeling are beginning to shed light on this interaction.
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Hu Y, Zhang W, Bao J, Wu Y, Yan M, Xiao Y, Yang L, Zhang Y, Wang J. A chimeric protein composed of the binding domains of Clostridium perfringens phospholipase C and Trueperella pyogenes pyolysin induces partial immunoprotection in a mouse model. Res Vet Sci 2016; 107:106-115. [PMID: 27473983 DOI: 10.1016/j.rvsc.2016.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 04/08/2016] [Accepted: 04/29/2016] [Indexed: 12/01/2022]
Abstract
Trueperella pyogenes and Clostridium perfringens are two kinds of conditional pathogens frequently associated with wound infections and succeeding lethal complications in various economic livestock. Pyolysin (PLO) and phospholipase C (PLC) are the key virulence factors of these two pathogens, respectively. In our study, a chimeric protein called rPC-PD4, which is composed of the binding regions of PLO and PLC, was synthesized. The toxicity of rPC-PD4 was evaluated. Results revealed that rPC-PD4 is a safe chimeric molecule that can be used to develop vaccines. Immunizing BALB/c mice with rPC-PD4 induced high titers of serum antibodies that could efficiently neutralize the hemolytic activity of recombinant PLO and PLC. After the challenge with T. pyogenes or C. perfringens was performed through the intraperitoneal route, we observed that rPC-PD4 immunization could provide partial immunoprotection and reduce lung, intestine, and liver tissue damage to mice. This work demonstrated the efficacy of the rationally designed rPC-PD4 chimeric protein as a potential vaccine candidate against C. perfringens and T. pyogenes.
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Affiliation(s)
- Yunhao Hu
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, P. R. China
| | - Wenlong Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, P. R. China.
| | - Jun Bao
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang 150030, P. R. China; National Food Safety and Nutrition Collaborative Innovation Center, Wuxi, Jiangsu 214122, P. R. China
| | - Yuhong Wu
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, P. R. China
| | - Minghui Yan
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, P. R. China
| | - Ya Xiao
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, P. R. China
| | - Lingxiao Yang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, P. R. China
| | - Yue Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, P. R. China
| | - Junwei Wang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, P. R. China; National Food Safety and Nutrition Collaborative Innovation Center, Wuxi, Jiangsu 214122, P. R. China.
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Yan M, Hu Y, Bao J, Xiao Y, Zhang Y, Yang L, Wang J, Zhang W. Isoleucine 61 is important for the hemolytic activity of pyolysin of Trueperella pyogenes. Vet Microbiol 2015; 182:196-201. [PMID: 26711048 DOI: 10.1016/j.vetmic.2015.11.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 11/20/2015] [Accepted: 11/22/2015] [Indexed: 11/16/2022]
Abstract
Pyolysin (PLO) is a hemolysin secreted by Trueperella pyogenes (T. pyogenes) and is important for the pathogenicity of T. pyogenes. Oligomerization of PLO monomers is a critical step in the process of hemolysis. However, the mechanisms of intermolecular interaction of PLO monomers are still not clearly illuminated. In this study, two monoclonal antibodies (mAbs) against PLO, named AP-1A3 and AP-4F12, respectively, were generated firstly, of which AP-1A3 showed no or undetectable hemolysis inhibition activity against recombinant PLO (rPLO), whereas AP-4F12 could markedly inhibit the hemolytic activity of rPLO. Epitope mapping revealed that AP-1A3 recognized amino acid residues ranging from 64 to 79 of mature PLO (91-106 including the signal peptide), whereas AP-4F12 recognized amino acid residues ranging from 58 to 75 (85-102 including the signal peptide). Comparison of the amino acid sequence of two epitopes revealed that six amino acid residues ranging from 58 to 63 of PLO were associated with the hemolytic activity of PLO. Alanine scan showed that substitution of each amino acid ranging from 58 to 62 with alanine had apparent impact on the hemolytic activity of rPLO, especially for the substitution of isoleucine 61 which caused almost complete loss of hemolytic activity of rPLO. Our findings identified a region in PLO and an amino acid in that region might play important role in the process of oligomerization of PLO monomers.
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Affiliation(s)
- Minghui Yan
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, PR China
| | - Yunhao Hu
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, PR China
| | - Jun Bao
- College of Animal Science and Technology, Northeast Agricultural University, Harbin, Heilongjiang 150030, PR China; National Food Safety and Nutrition Collaborative Innovation Center, Wuxi, Jiangsu 214122, PR China
| | - Ya Xiao
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, PR China
| | - Yue Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, PR China
| | - Lingxiao Yang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, PR China
| | - Junwei Wang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, PR China; National Food Safety and Nutrition Collaborative Innovation Center, Wuxi, Jiangsu 214122, PR China.
| | - Wenlong Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang 150030, PR China.
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Johnson BB, Heuck AP. Perfringolysin O structure and mechanism of pore formation as a paradigm for cholesterol-dependent cytolysins. Subcell Biochem 2014; 80:63-81. [PMID: 24798008 DOI: 10.1007/978-94-017-8881-6_5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cholesterol-dependent cytolysins (CDCs) constitute a family of pore forming toxins secreted by Gram-positive bacteria. These toxins form transmembrane pores by inserting a large β-barrel into cholesterol-containing membrane bilayers. Binding of water-soluble CDCs to the membrane triggers the formation of oligomers containing 35-50 monomers. The coordinated insertion of more than seventy β-hairpins into the membrane requires multiple structural conformational changes. Perfringolysin O (PFO), secreted by Clostridium perfringens, has become the prototype for the CDCs. In this chapter, we will describe current knowledge on the mechanism of PFO cytolysis, with special focus on cholesterol recognition, oligomerization, and the conformational changes involved in pore formation.
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Affiliation(s)
- Benjamin B Johnson
- Department of Biochemistry and Molecular Biology, University of Massachusetts, 710 N. Pleasant St., Lederle GRT, Amherst, MA, 01003, USA
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The cholesterol-dependent cytolysin signature motif: a critical element in the allosteric pathway that couples membrane binding to pore assembly. PLoS Pathog 2012; 8:e1002787. [PMID: 22792065 PMCID: PMC3390400 DOI: 10.1371/journal.ppat.1002787] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Accepted: 05/19/2012] [Indexed: 12/03/2022] Open
Abstract
The cholesterol-dependent cytolysins (CDCs) constitute a family of pore-forming toxins that contribute to the pathogenesis of a large number of Gram-positive bacterial pathogens.The most highly conserved region in the primary structure of the CDCs is the signature undecapeptide sequence (ECTGLAWEWWR). The CDC pore forming mechanism is highly sensitive to changes in its structure, yet its contribution to the molecular mechanism of the CDCs has remained enigmatic. Using a combination of fluorescence spectroscopic methods we provide evidence that shows the undecapeptide motif of the archetype CDC, perfringolysin O (PFO), is a key structural element in the allosteric coupling of the cholesterol-mediated membrane binding in domain 4 (D4) to distal structural changes in domain 3 (D3) that are required for the formation of the oligomeric pore complex. Loss of the undecapeptide function prevents all measurable D3 structural transitions, the intermolecular interaction of membrane bound monomers and the assembly of the oligomeric pore complex. We further show that this pathway does not exist in intermedilysin (ILY), a CDC that exhibits a divergent undecapeptide and that has evolved to use human CD59 rather than cholesterol as its receptor. These studies show for the first time that the undecapeptide of the cholesterol-binding CDCs forms a critical element of the allosteric pathway that controls the assembly of the pore complex. The CDCs are a large family of pathogenesis-associated pore-forming toxins that are expressed by many Gram-positive pathogens. The conserved undecapeptide motif of the CDCs has been regarded as the signature peptide sequence for these toxins, yet its function has remained obscure. The studies herein show that the undecapeptide forms a critical structural element in the allosteric pathway that couples membrane binding to cholesterol to the initiation of distal structural changes, which are required for the assembly of the pore forming complex. These studies provide the first insight into the function of this highly conserved sequence and show that through evolution this pathway is missing in the CD59-binding CDCs.
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Jost BH, Lucas EA, Billington SJ, Ratner AJ, McGee DJ. Arcanolysin is a cholesterol-dependent cytolysin of the human pathogen Arcanobacterium haemolyticum. BMC Microbiol 2011; 11:239. [PMID: 22029628 PMCID: PMC3215231 DOI: 10.1186/1471-2180-11-239] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 10/26/2011] [Indexed: 12/20/2022] Open
Abstract
Background Arcanobacterium haemolyticum is an emerging human pathogen that causes pharyngitis, wound infections, and a variety of occasional invasive diseases. Since its initial discovery in 1946, this Gram positive organism has been known to have hemolytic activity, yet no hemolysin has been previously reported. A. haemolyticum also displays variable hemolytic activity on laboratory blood agar that is dependent upon which species the blood is derived. Results Here we describe a cholesterol-dependent cytolysin (CDC) secreted by A. haemolyticum, designated arcanolysin (aln), which is present in all strains (n = 52) tested by DNA dot hybridization. Among the known CDCs, ALN is most closely related to pyolysin (PLO) from Trueperella (formerly Arcanobacterium) pyogenes. The aln probe, however, did not hybridize to DNA from T. pyogenes. The aln open reading frame has a lower mol %G+C (46.7%) than the rest of the A. haemolyticum genome (53.1%) and is flanked by two tRNA genes, consistent with probable acquisition by horizontal transfer. The ALN protein (~ 64 kDa) contains a predicted signal sequence, a putative PEST sequence, and a variant undecapeptide within domain 4, which is typically important for function of the toxins. The gene encoding ALN was cloned and expressed in Escherichia coli as a functional recombinant toxin. Recombinant ALN had hemolytic activity on erythrocytes and cytolytic activity on cultured cells from human, rabbit, pig and horse origins but was poorly active on ovine, bovine, murine, and canine cells. ALN was less sensitive to inhibition by free cholesterol than perfringolysin O, consistent with the presence of the variant undecapeptide. Conclusions ALN is a newly identified CDC with hemolytic activity and unique properties in the CDC family and may be a virulence determinant for A. haemolyticum.
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Affiliation(s)
- B Helen Jost
- Department of Veterinary Science and Microbiology, The University of Arizona, 1117 E Lowell Street, Tucson, AZ 85721, USA
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11
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Harris JR, Lewis RJ, Baik C, Pokrajac L, Billington SJ, Palmer M. Cholesterol microcrystals and cochleate cylinders: attachment of pyolysin oligomers and domain 4. J Struct Biol 2010; 173:38-45. [PMID: 20682347 DOI: 10.1016/j.jsb.2010.07.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 07/16/2010] [Accepted: 07/27/2010] [Indexed: 11/15/2022]
Abstract
Using an established organic solvent injection procedure for the preparation of aqueous cholesterol microcrystal suspensions, it has now been shown that a new, hollow, cylindrical, tightly-coiled, multi-bilayer form of cholesterol can be generated, termed the cochleate cylinder. Cholesterol cochleate cylinders are formed in larger numbers at intermediate temperatures (40-75°C) but are not formed at 100°C. The structure of the cholesterol microcrystals and cochleate cylinders is shown in negatively stained electron micrographs. Oligomerization and attachment of pyolysin to cholesterol microcrystals and cochleate cylinders is shown, as is the attachment of the pyolysin "cholesterol-binding" domain 4 (D4) fragment. The bound D4 domain forms a linear array on the two planar surfaces and edges of the cholesterol microcrystals and a quasi helical array on the surface of the cochleate cylinders. Little evidence has been obtained to support the possibility that interaction or hetero-oligomerization can occur between intact pyolysin and the pyolysin D4 fragment on the surface of cholesterol microcrystals. Using immobilized cholesterol crystals attached to a carbon support film, single-sided linear labelling of the cholesterol surface with pyolysin D4 has been achieved, which correlates well with the images from the microcrystal suspensions and our earlier data using non-cytolytic streptolysin O mutants.
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Affiliation(s)
- J Robin Harris
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle-upon-Tyne NE2 4HH, UK.
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The aromatic ring of phenylalanine 334 is essential for oligomerization of Vibrio vulnificus hemolysin. J Bacteriol 2009; 192:568-74. [PMID: 19897654 DOI: 10.1128/jb.01049-09] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus hemolysin (VVH) is thought to be a member of the cholesterol-dependent cytolysin (CDC) family of pore-forming toxins. To date, the structure-function relationships of CDCs produced by Gram-negative bacteria remain largely unknown. We show here that the aromatic ring of phenylalanine residue conserved in Vibrionaceae hemolysins is essential for oligomerization of VVH. We generated the VVH mutants; substituted Phe 334 for Ile (F334I), Ala (F334A), Tyr (F334Y), or Trp (F334W); and tested their binding and oligomerizing activity on Chinese hamster ovary cells. Binding in all mutants fell by approximately 50% compared with that in the wild type. Oligomerizing activities were completely eliminated in F334I and F334A mutants, whereas this ability was partially retained in F334Y and F334W mutants. These findings indicate that both hydrophobicity and an aromatic ring residue at the 334th position were needed for full binding activity and that the oligomerizing activity of this toxin was dependent on the existence of an aromatic ring residue at the 334th position. Our findings might help further understanding of the structure-and-function relationships in Vibrionaceae hemolysins.
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Functional and phylogenetic characterization of Vaginolysin, the human-specific cytolysin from Gardnerella vaginalis. J Bacteriol 2008; 190:3896-903. [PMID: 18390664 DOI: 10.1128/jb.01965-07] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pore-forming toxins are essential to the virulence of a wide variety of pathogenic bacteria. Gardnerella vaginalis is a bacterial species associated with bacterial vaginosis (BV) and its significant adverse sequelae, including preterm birth and acquisition of human immunodeficiency virus. G. vaginalis makes a protein toxin that generates host immune responses and has been hypothesized to be involved in the pathogenesis of BV. We demonstrate that G. vaginalis produces a toxin (vaginolysin [VLY]) that is a member of the cholesterol-dependent cytolysin (CDC) family, most closely related to intermedilysin from Streptococcus intermedius. Consistent with this predicted relationship, VLY lyses target cells in a species-specific manner, dependent upon the complement regulatory molecule CD59. In addition to causing erythrocyte lysis, VLY activates the conserved epithelial p38 mitogen-activated protein kinase pathway and induces interleukin-8 production by human epithelial cells. Transfection of human CD59 into nonsusceptible cells renders them sensitive to VLY-mediated lysis. In addition, a single amino acid substitution in the VLY undecapeptide [VLY(P480W)] generates a toxoid that does not form pores, and introduction of the analogous proline residue into another CDC, pneumolysin, significantly decreases its cytolytic activity. Further investigation of the mechanism of action of VLY may improve understanding of the functions of the CDC family as well as diagnosis and therapy for BV.
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Jost BH, Billington SJ. Arcanobacterium pyogenes: molecular pathogenesis of an animal opportunist. Antonie van Leeuwenhoek 2005; 88:87-102. [PMID: 16096685 DOI: 10.1007/s10482-005-2316-5] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Accepted: 02/15/2005] [Indexed: 10/25/2022]
Abstract
Arcanobacterium pyogenes is a commensal and an opportunistic pathogen of economically important livestock, causing diseases as diverse as mastitis, liver abscessation and pneumonia. This organism possesses a number of virulence factors that contribute to its pathogenic potential. A. pyogenes expresses a cholesterol-dependent cytolysin, pyolysin, which is a haemolysin and is cytolytic for immune cells, including macrophages. Expression of pyolysin is required for virulence and this molecule is the most promising vaccine candidate identified to date. A. pyogenes also possesses a number of adherence mechanisms, including two neuraminidases, the action of which are required for full adhesion to epithelial cells, and several extracellular matrix-binding proteins, including a collagen-binding protein, which may be required for adhesion to collagen-rich tissue. A. pyogenes also expresses fimbriae, which are similar to the type 2 fimbriae of Actinomyces naeslundii, and forms biofilms. However, the role of these factors in the pathogenesis of A. pyogenes infections remains to be elucidated. A. pyogenes also invades and survives within epithelial cells and can survive within J774A.1 macrophages for up to 72 h, suggesting an important role for A. pyogenes interaction with host cells during pathogenesis. The two component regulatory system, PloSR, up-regulates pyolysin expression and biofilm formation but down-regulates expression of proteases, suggesting that it may act as a global regulator of A. pyogenes virulence. A. pyogenes is a versatile pathogen, with an arsenal of virulence determinants. However, most aspects of the pathogenesis of infection caused by this important opportunistic pathogen remain poorly characterized.
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Affiliation(s)
- B Helen Jost
- Department of Veterinary Science and Microbiology, University of Arizona, 1117 East Lowell Street, Tucson, AZ 85721, USA.
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Affiliation(s)
- Rodney K Tweten
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, 73104, USA.
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Nagamune H, Ohkura K, Sukeno A, Cowan G, Mitchell TJ, Ito W, Ohnishi O, Hattori K, Yamato M, Hirota K, Miyake Y, Maeda T, Kourai H. The human-specific action of intermedilysin, a homolog of streptolysin O, is dictated by domain 4 of the protein. Microbiol Immunol 2005; 48:677-92. [PMID: 15383705 DOI: 10.1111/j.1348-0421.2004.tb03479.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Intermedilysin is a pore-forming cytolysin belonging to the streptolysin O gene family known as the 'Cholesterol-binding/dependent cytolysins' and is unique within the family in that it is highly humanspecific. This specificity suggests interaction with a component of human cells other than cholesterol, the proposed receptor for the other toxins of the gene family. Indeed, intermedilysin showed no significant degree of affinity to free or liposome-embedded cholesterol. Characterization of intermedilysin undecapeptide mutants revealed that this lack of affinity to cholesterol was a result of the substitutions of intermedilysin in this region. Absorption assays with erythrocyte membranes from various animals, competitive inhibition with domain 4 of intermedilysin and liposome-binding assays of streptolysin O and intermedilysin indicated that cell membrane binding is the human-specific step of intermedilysin action, that the host cell membrane-binding site is located within domain 4 in common with other members of the family and that the receptor for this toxin is not cholesterol. The species specificity of undecapeptide mutants of intermedilysin and streptolysin O and chimeric mutants between intermedilysin and streptolysin O, and intermedilysin and pneumolysin indicated that domain 4 of intermedilysin determines the human-specific action step and the cell-binding site of domain 4 lies within the 56 amino acids of the C-terminal, excluding the undecapeptide region.
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Affiliation(s)
- Hideaki Nagamune
- Department of Biological Science and Technology, Faculty of Engineering, The University of Tokushima, #1, 2-chrome, Minamijosanjima-cho, Tokushima, Tokushima 770-8506, Japan.
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Jost BH, Trinh HT, Songer JG, Billington SJ. Immunization with genetic toxoids of the Arcanobacterium pyogenes cholesterol-dependent cytolysin, pyolysin, protects mice against infection. Infect Immun 2003; 71:2966-9. [PMID: 12704180 PMCID: PMC153263 DOI: 10.1128/iai.71.5.2966-2969.2003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pyolysin (PLO), a cholesterol-dependent cytolysin expressed by Arcanobacterium pyogenes, is an important host-protective antigen. However, this molecule is toxic and requires inactivation prior to its use as a vaccine. Three genetically toxoided, nonhemolytic PLO molecules, HIS-PLO.F(497), HIS-PLO.Delta P(499), and HIS-PLO.A(522), were found to be nontoxic, and vaccinated mice were protected from infection, indicating the potential of these toxoids as vaccines. Furthermore, in a mouse model of infection, A. pyogenes carrying the F(497) mutation was as attenuated as a PLO-deficient strain, indicating that the cytolytic activity of PLO is important in virulence.
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Affiliation(s)
- B Helen Jost
- Department of Veterinary Science and Microbiology, The University of Arizona, Tucson, Arizona 85721, USA.
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