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Sychla A, Stach CS, Roach SN, Hayward AN, Langlois RA, Smanski MJ. High-throughput investigation of genetic design constraints in domesticated Influenza A Virus for transient gene delivery. bioRxiv 2024:2024.02.14.580300. [PMID: 38405907 PMCID: PMC10888799 DOI: 10.1101/2024.02.14.580300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Replication-incompetent single cycle infectious Influenza A Virus (sciIAV) has demonstrated utility as a research and vaccination platform. Protein-based therapeutics are increasingly attractive due to their high selectivity and potent efficacy but still suffer from low bioavailability and high manufacturing cost. Transient RNA-mediated delivery is a safe alternative that allows for expression of protein-based therapeutics within the target cells or tissues but is limited by delivery efficiency. Here, we develop recombinant sciIAV as a platform for transient gene delivery in vivo and in vitro for therapeutic, research, and manufacturing applications (in vivo antimicrobial production, cell culture contamination clearance, and production of antiviral proteins in vitro). While adapting the system to deliver new protein cargo we discovered expression differences presumably resulting from genetic context effects. We applied a high-throughput screen to map these within the 3'-untranslated and coding regions of the hemagglutinin-encoding segment 4. This screen revealed permissible mutations in the 3'-UTR and depletion of RNA level motifs in the N-terminal coding region.
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Affiliation(s)
- Adam Sychla
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Biotechnology Institute, University of Minnesota, Saint Paul, MN 55108
| | - Christopher S Stach
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Biotechnology Institute, University of Minnesota, Saint Paul, MN 55108
| | - Shanley N Roach
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Department of Microbiology and Immunology, University of Minnesota, Saint Paul, MN 55108
| | - Amanda N Hayward
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Biotechnology Institute, University of Minnesota, Saint Paul, MN 55108
| | - Ryan A Langlois
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Department of Microbiology and Immunology, University of Minnesota, Saint Paul, MN 55108
| | - Michael J Smanski
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Saint Paul, MN 55108
- Biotechnology Institute, University of Minnesota, Saint Paul, MN 55108
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Stach CS, McCann MG, O’Brien CM, Le TS, Somia N, Chen X, Lee K, Fu HY, Daoutidis P, Zhao L, Hu WS, Smanski M. Model-Driven Engineering of N-Linked Glycosylation in Chinese Hamster Ovary Cells. ACS Synth Biol 2019; 8:2524-2535. [PMID: 31596566 DOI: 10.1021/acssynbio.9b00215] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Chinese hamster ovary (CHO) cells are used for industrial production of protein-based therapeutics (i.e., "biologics"). Here we describe a method for combining systems-level kinetic models with a synthetic biology platform for multigene overexpression to rationally perturb N-linked glycosylation. Specifically, we sought to increase galactose incorporation on a secreted Immunoglobulin G (IgG) protein. We rationally design, build, and test a total of 23 transgenic cell pools that express single or three-gene glycoengineering cassettes comprising a total of 100 kilobases of engineered DNA sequence. Through iterative engineering and model refinement, we rationally increase the fraction of bigalactosylated glycans five-fold from 11.9% to 61.9% and simultaneously decrease the glycan heterogeneity on the secreted IgG. Our approach allows for rapid hypothesis testing and identification of synergistic behavior from genetic perturbations by bridging systems and synthetic biology.
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Affiliation(s)
| | | | | | | | | | - Xinning Chen
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P.R. China
| | | | | | | | - Liang Zhao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, P.R. China
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O’Brien SA, Lee K, Fu HY, Lee Z, Le TS, Stach CS, McCann MG, Zhang AQ, Smanski MJ, Somia NV, Hu WS. Single Copy Transgene Integration in a Transcriptionally Active Site for Recombinant Protein Synthesis. Biotechnol J 2018; 13:e1800226. [PMID: 30024101 PMCID: PMC7058118 DOI: 10.1002/biot.201800226] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 07/09/2018] [Indexed: 12/21/2022]
Abstract
For the biomanufacturing of protein biologics, establishing stable cell lines with high transgene transcription is critical for high productivity. Modern genome engineering tools can direct transgene insertion to a specified genomic locus and can potentially become a valuable tool for cell line generation. In this study, the authors survey transgene integration sites and their transcriptional activity to identify characteristics of desirable regions. A lentivirus containing destabilized Green Fluorescent Protein (dGFP) is used to infect Chinese hamster ovary cells at a low multiplicity of infection, and cells with high or low GFP fluorescence are isolated. RNA sequencing and Assay for Transposase Accessible Chromatin using sequencing data shows integration sites with high GFP expression are in larger regions of high transcriptional activity and accessibility, but not necessarily within highly transcribed genes. This method is used to obtain high Immunoglobulin G (IgG) expressing cell lines with a single copy of the transgene integrated into transcriptionally active and accessible genomic regions. Dual recombinase-mediated cassette exchange is then employed to swap the IgG transgene for erythropoietin or tumor necrosis factor receptor-Fc. This work thus highlights a strategy to identify desirable sites for transgene integration and to streamline the development of new product producing cell lines.
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Affiliation(s)
- Sofie A. O’Brien
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 USA
| | - Kyoungho Lee
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 USA
| | - Hsu-Yuan Fu
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 USA
| | - Zion Lee
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 USA
| | - Tung S. Le
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 USA
| | - Christopher S. Stach
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455-0132 USA
| | - Meghan G. McCann
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 USA
| | - Alicia Q. Zhang
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 USA
| | - Michael J. Smanski
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455-0132 USA
| | - Nikunj V. Somia
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455-0132 USA
| | - Wei-Shou Hu
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 USA
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Breshears LM, Gillman AN, Stach CS, Schlievert PM, Peterson ML. Local Epidermal Growth Factor Receptor Signaling Mediates the Systemic Pathogenic Effects of Staphylococcus aureus Toxic Shock Syndrome. PLoS One 2016; 11:e0158969. [PMID: 27414801 PMCID: PMC4944920 DOI: 10.1371/journal.pone.0158969] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 06/26/2016] [Indexed: 12/02/2022] Open
Abstract
Secreted factors of Staphylococcus aureus can activate host signaling from the epidermal growth factor receptor (EGFR). The superantigen toxic shock syndrome toxin-1 (TSST-1) contributes to mucosal cytokine production through a disintegrin and metalloproteinase (ADAM)-mediated shedding of EGFR ligands and subsequent EGFR activation. The secreted hemolysin, α-toxin, can also induce EGFR signaling and directly interacts with ADAM10, a sheddase of EGFR ligands. The current work explores the role of EGFR signaling in menstrual toxic shock syndrome (mTSS), a disease mediated by TSST-1. The data presented show that TSST-1 and α-toxin induce ADAM- and EGFR-dependent cytokine production from human vaginal epithelial cells. TSST-1 and α-toxin also induce cytokine production from an ex vivo porcine vaginal mucosa (PVM) model. EGFR signaling is responsible for the majority of IL-8 production from PVM in response to secreted toxins and live S. aureus. Finally, data are presented demonstrating that inhibition of EGFR signaling with the EGFR-specific tyrosine kinase inhibitor AG1478 significantly increases survival in a rabbit model of mTSS. These data indicate that EGFR signaling is critical for progression of an S. aureus exotoxin-mediated disease and may represent an attractive host target for therapeutics.
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Affiliation(s)
- Laura M. Breshears
- University of Minnesota, College of Pharmacy, Department of Experimental and Clinical Pharmacology, Minneapolis, Minnesota, United States of America
| | - Aaron N. Gillman
- University of Minnesota, College of Pharmacy, Department of Experimental and Clinical Pharmacology, Minneapolis, Minnesota, United States of America
| | - Christopher S. Stach
- University of Minnesota, College of Biological Sciences, Biotechnology Institute, Minneapolis, Minnesota, United States of America
| | - Patrick M. Schlievert
- University of Iowa, Carver College of Medicine, Department of Microbiology, Iowa City, Iowa, United States of America
| | - Marnie L. Peterson
- University of Minnesota, College of Pharmacy, Department of Experimental and Clinical Pharmacology, Minneapolis, Minnesota, United States of America
- * E-mail:
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Stach CS, Vu BG, Merriman JA, Herrera A, Cahill MP, Schlievert PM, Salgado-Pabón W. Novel Tissue Level Effects of the Staphylococcus aureus Enterotoxin Gene Cluster Are Essential for Infective Endocarditis. PLoS One 2016; 11:e0154762. [PMID: 27124393 PMCID: PMC4849672 DOI: 10.1371/journal.pone.0154762] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 04/18/2016] [Indexed: 01/01/2023] Open
Abstract
Background Superantigens are indispensable virulence factors for Staphylococcus aureus in disease causation. Superantigens stimulate massive immune cell activation, leading to toxic shock syndrome (TSS) and contributing to other illnesses. However, superantigens differ in their capacities to induce body-wide effects. For many, their production, at least as tested in vitro, is not high enough to reach the circulation, or the proteins are not efficient in crossing epithelial and endothelial barriers, thus remaining within tissues or localized on mucosal surfaces where they exert only local effects. In this study, we address the role of TSS toxin-1 (TSST-1) and most importantly the enterotoxin gene cluster (egc) in infective endocarditis and sepsis, gaining insights into the body-wide versus local effects of superantigens. Methods We examined S. aureus TSST-1 gene (tstH) and egc deletion strains in the rabbit model of infective endocarditis and sepsis. Importantly, we also assessed the ability of commercial human intravenous immunoglobulin (IVIG) plus vancomycin to alter the course of infective endocarditis and sepsis. Results TSST-1 contributed to infective endocarditis vegetations and lethal sepsis, while superantigens of the egc, a cluster with uncharacterized functions in S. aureus infections, promoted vegetation formation in infective endocarditis. IVIG plus vancomycin prevented lethality and stroke development in infective endocarditis and sepsis. Conclusions Our studies support the local tissue effects of egc superantigens for establishment and progression of infective endocarditis providing evidence for their role in life-threatening illnesses. In contrast, TSST-1 contributes to both infective endocarditis and lethal sepsis. IVIG may be a useful adjunct therapy for infective endocarditis and sepsis.
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Affiliation(s)
- Christopher S. Stach
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, United States of America
| | - Bao G. Vu
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, United States of America
| | - Joseph A. Merriman
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, United States of America
| | - Alfa Herrera
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, United States of America
| | - Michael P. Cahill
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, United States of America
| | - Patrick M. Schlievert
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, United States of America
- * E-mail:
| | - Wilmara Salgado-Pabón
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City, IA, 52242, United States of America
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Herrera A, Vu BG, Stach CS, Merriman JA, Horswill AR, Salgado-Pabón W, Schlievert PM. Staphylococcus aureus β-Toxin Mutants Are Defective in Biofilm Ligase and Sphingomyelinase Activity, and Causation of Infective Endocarditis and Sepsis. Biochemistry 2016; 55:2510-7. [PMID: 27015018 DOI: 10.1021/acs.biochem.6b00083] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
β-Toxin is an important virulence factor of Staphylococcus aureus, contributing to colonization and development of disease [Salgado-Pabon, W., et al. (2014) J. Infect. Dis. 210, 784-792; Huseby, M. J., et al. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 14407-14412; Katayama, Y., et al. (2013) J. Bacteriol. 195, 1194-1203]. This cytotoxin has two distinct mechanisms of action: sphingomyelinase activity and DNA biofilm ligase activity. However, the distinct mechanism that is most important for its role in infective endocarditis is unknown. We characterized the active site of β-toxin DNA biofilm ligase activity by examining deficiencies in site-directed mutants through in vitro DNA precipitation and biofilm formation assays. Possible conformational changes in mutant structure compared to that of wild-type toxin were assessed preliminarily by trypsin digestion analysis, retention of sphingomyelinase activity, and predicted structures based on the native toxin structure. We addressed the contribution of each mechanism of action to producing infective endocarditis and sepsis in vivo in a rabbit model. The H289N β-toxin mutant, lacking sphingomyelinase activity, exhibited lower sepsis lethality and infective endocarditis vegetation formation compared to those of the wild-type toxin. β-Toxin mutants with disrupted biofilm ligase activity did not exhibit decreased sepsis lethality but were deficient in infective endocarditis vegetation formation compared to the wild-type protein. Our study begins to characterize the DNA biofilm ligase active site of β-toxin and suggests β-toxin functions importantly in infective endocarditis through both of its mechanisms of action.
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Affiliation(s)
- Alfa Herrera
- Department of Microbiology, University of Iowa Carver College of Medicine , Iowa City, Iowa 52242, United States
| | - Bao G Vu
- Department of Microbiology, University of Iowa Carver College of Medicine , Iowa City, Iowa 52242, United States
| | - Christopher S Stach
- Department of Microbiology, University of Iowa Carver College of Medicine , Iowa City, Iowa 52242, United States
| | - Joseph A Merriman
- Department of Microbiology, University of Iowa Carver College of Medicine , Iowa City, Iowa 52242, United States
| | - Alexander R Horswill
- Department of Microbiology, University of Iowa Carver College of Medicine , Iowa City, Iowa 52242, United States
| | - Wilmara Salgado-Pabón
- Department of Microbiology, University of Iowa Carver College of Medicine , Iowa City, Iowa 52242, United States
| | - Patrick M Schlievert
- Department of Microbiology, University of Iowa Carver College of Medicine , Iowa City, Iowa 52242, United States
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Stach CS, Schlievert PM. Lipopolysaccharide-Induced Toxic Shock Syndrome in Rabbits. Methods Mol Biol 2016; 1396:67-71. [PMID: 26676037 DOI: 10.1007/978-1-4939-3344-0_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Enhancement of susceptibility to lipopolysaccharide (LPS; endotoxin) is a defining characteristic of Staphylococcus aureus superantigens. At the time of this publication, there are 24 identified staphylococcal superantigens (SAgs), some of which have yet to be fully characterized. Testing the capacity of superantigens to potentiate LPS sensitivity is essential to characterize the role of these proteins in disease development. Here we describe how to perform studies of the enhancement of LPS-induced toxic shock syndrome in rabbits. This protocol also provides information on a second important activity of superantigens: the production of fever.
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Affiliation(s)
- Christopher S Stach
- Department of Microbiology, University of Iowa, 51 Newton Road, Bowen Science Building 3-403, Iowa City, IA, 52242, USA
| | - Patrick M Schlievert
- Department of Microbiology, University of Iowa, 51 Newton Road, Bowen Science Building 3-403, Iowa City, IA, 52242, USA.
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Stach CS, Vu BG, Schlievert PM. Determining the Presence of Superantigens in Coagulase Negative Staphylococci from Humans. PLoS One 2015; 10:e0143341. [PMID: 26599862 PMCID: PMC4658126 DOI: 10.1371/journal.pone.0143341] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 11/03/2015] [Indexed: 01/23/2023] Open
Abstract
Superantigens (SAgs) are important virulence factors in S. aureus. Recent studies identified their presence in animal coagulase-negative staphylococci (CNS). The emergence of human-associated SAg+ CNS would mark a prodigious shift in virulence capabilities. We examined CNS isolates from healthy human nares and diseased individuals, and determined that no known SAgs were present.
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Affiliation(s)
- Christopher S. Stach
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Bao G. Vu
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Patrick M. Schlievert
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
- * E-mail:
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Abstract
Staphylococcus aureus strains that cause human diseases produce a large family of pyrogenic toxin superantigens (SAgs). These include toxic shock syndrome toxin-1 (TSST-1), the staphylococcal enterotoxins (SEs), and the SE-like proteins; to date, 23 staphylococcal SAgs have been described. Among the SAgs, three have been highly associated with human diseases (TSST-1, SEB, and SEC), likely because they are produced in high concentrations compared to other SAgs. Another major family of exotoxins produced by S. aureus is the cytolysins, particularly α-, β-, γ-, and δ-toxins, phenol soluble modulins, and leukocidins. This review discusses the association of SAgs with human diseases and particularly the "outside-in" signaling mechanism that leads to SAg-associated diseases. We discuss SAg interactions with three host immune cell receptors, including variable regions of the β-chain of the T cell receptor, MHC II α- and/or β-chains, and an epithelial/endothelial cell receptor that may include CD40. To a lesser extent, we discuss the role of cytolysins in facilitating disease production by SAgs.
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Affiliation(s)
- Christopher S Stach
- Department of Microbiology, Carver College of Medicine, University of Iowa, 51 Newton Road, Iowa City, IA, 52242, USA
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Vu BG, Stach CS, Salgado-Pabón W, Diekema DJ, Gardner SE, Schlievert PM. Superantigens of Staphylococcus aureus from patients with diabetic foot ulcers. J Infect Dis 2014; 210:1920-7. [PMID: 24951827 DOI: 10.1093/infdis/jiu350] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Diabetic foot ulcer (DFU) infections are challenging. Staphylococcus aureus is the most commonly isolated pathogen in DFUs. Superantigens (SAgs) are causative in many S. aureus infections. We hypothesized both that DFU S. aureus will produce large SAg numbers, consistent with skin infections, and that certain SAgs will be overrepresented. We assessed the SAg and α-toxin profile of isolates from patients with DFU, compared with profiles of isolates from other sources. MATERIALS Twenty-five S. aureus isolates from patients with DFU were characterized. Polymerase chain reaction was used to detect genes for methicillin-resistance and SAgs. Some SAgs and the α-toxin were quantified. We compared the SAg profile of DFU isolates with SAg profiles of S. aureus isolates from skin lesions of patients with atopic dermatitis and from vaginal mucosa of healthy individuals. RESULTS Most DFU isolates were methicillin susceptible (64%), with USA100 the most common clonal group. The SAg gene profile of DFU isolates most closely resembled that of isolates from patients with atopic dermatitis, with the highest number of different SAg genes per isolate and a high prevalence of staphylococcal enterotoxin D and the enterotoxin gene cluster. DFU isolates also had a high prevalence of staphylococcal enterotoxin-like X. CONCLUSIONS Comparison of the SAg profile of DFU isolates to SAg profiles of skin lesion isolates and vaginal mucosa isolates revealed that the SAg profile of DFU isolates was more similar to that of skin lesion isolates. SAgs offer selective advantages in facilitating DFU infections and suggest that therapies to neutralize or reduce SAg production by S. aureus may be beneficial in management of patients with DFU.
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Salgado-Pabón W, Herrera A, Vu BG, Stach CS, Merriman JA, Spaulding AR, Schlievert PM. Staphylococcus aureus β-toxin production is common in strains with the β-toxin gene inactivated by bacteriophage. J Infect Dis 2014; 210:784-92. [PMID: 24620023 DOI: 10.1093/infdis/jiu146] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Staphylococcus aureus causes life-threatening infections, including infective endocarditis, sepsis, and pneumonia. β-toxin is a sphingomyelinase encoded for by virtually all S. aureus strains and exhibits human immune cell cytotoxicity. The toxin enhances S. aureus phenol-soluble modulin activity, and its activity is enhanced by superantigens. The bacteriophage φSa3 inserts into the β-toxin gene in human strains, inactivating it in the majority of S. aureus clonal groups. Hence, most strains are reported not to secrete β-toxin. METHODS This dynamic was investigated by examining β-toxin production by multiple clonal groups of S. aureus, both in vitro and in vivo during infections in rabbit models of infective endocarditis, sepsis, and pneumonia. RESULTS β-toxin phenotypic variants are common among strains containing φSa3. In vivo, φSa3 is differentially induced in heart vegetations, kidney abscesses, and ischemic liver compared to spleen and blood, and in vitro growth in liquid culture. Furthermore, in pneumonia, wild-type β-toxin production leads to development of large caseous lesions, and in infective endocarditis, increases the size of pathognomonic vegetations. CONCLUSIONS This study demonstrates the dynamic interaction between S. aureus and the infected host, where φSa3 serves as a regulator of virulence gene expression, and increased fitness and virulence in new environments.
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Affiliation(s)
- Wilmara Salgado-Pabón
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City
| | - Alfa Herrera
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City
| | - Bao G Vu
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City
| | - Christopher S Stach
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City
| | - Joseph A Merriman
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City
| | - Adam R Spaulding
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City
| | - Patrick M Schlievert
- Department of Microbiology, University of Iowa Carver College of Medicine, Iowa City
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Spaulding AR, Salgado-Pabón W, Merriman JA, Stach CS, Ji Y, Gillman AN, Peterson ML, Schlievert PM. Vaccination against Staphylococcus aureus pneumonia. J Infect Dis 2013; 209:1955-62. [PMID: 24357631 DOI: 10.1093/infdis/jit823] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Staphylococcus aureus causes serious infections in both hospital and community settings. Attempts have been made to prevent human infection through vaccination against bacterial cell-surface antigens; thus far all have failed. Here we show that superantigens and cytolysins, when used in vaccine cocktails, provide protection from S. aureus USA100-USA400 intrapulmonary challenge. METHODS Rabbits were actively vaccinated (wild-type toxins or toxoids) or passively immunized (hyperimmune serum) against combinations of superantigens (toxic shock syndrome toxin 1, enterotoxins B and C, and enterotoxin-like X) and cytolysins (α-, β-, and γ-toxins) and challenged intrapulmonarily with multiple strains of S. aureus, both methicillin-sensitive and methicillin-resistant. RESULTS Active vaccination against a cocktail containing bacterial cell-surface antigens enhanced disease severity as tested by infective endocarditis. Active vaccination against secreted superantigens and cytolysins resulted in protection of 86 of 88 rabbits when challenged intrapulmonarily with 9 different S. aureus strains, compared to only 1 of 88 nonvaccinated animals. Passive immunization studies demonstrated that production of neutralizing antibodies was an important mechanism of protection. CONCLUSIONS The data suggest that vaccination against bacterial cell-surface antigens increases disease severity, but vaccination against secreted virulence factors provides protection against S. aureus. These results advance our understanding of S. aureus pathogenesis and have important implications in disease prevention.
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Affiliation(s)
- Adam R Spaulding
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City
| | - Wilmara Salgado-Pabón
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City
| | - Joseph A Merriman
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City
| | - Christopher S Stach
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City
| | - Yinduo Ji
- Department of Veterinary Biosciences, College of Veterinary Medicine
| | - Aaron N Gillman
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis
| | - Marnie L Peterson
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis
| | - Patrick M Schlievert
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City
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