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Lê-Bury P, Echenique-Rivera H, Pizarro-Cerdá J, Dussurget O. Determinants of bacterial survival and proliferation in blood. FEMS Microbiol Rev 2024; 48:fuae013. [PMID: 38734892 PMCID: PMC11163986 DOI: 10.1093/femsre/fuae013] [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: 11/06/2023] [Revised: 04/29/2024] [Accepted: 05/10/2024] [Indexed: 05/13/2024] Open
Abstract
Bloodstream infection is a major public health concern associated with high mortality and high healthcare costs worldwide. Bacteremia can trigger fatal sepsis whose prevention, diagnosis, and management have been recognized as a global health priority by the World Health Organization. Additionally, infection control is increasingly threatened by antimicrobial resistance, which is the focus of global action plans in the framework of a One Health response. In-depth knowledge of the infection process is needed to develop efficient preventive and therapeutic measures. The pathogenesis of bloodstream infection is a dynamic process resulting from the invasion of the vascular system by bacteria, which finely regulate their metabolic pathways and virulence factors to overcome the blood immune defenses and proliferate. In this review, we highlight our current understanding of determinants of bacterial survival and proliferation in the bloodstream and discuss their interactions with the molecular and cellular components of blood.
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Affiliation(s)
- Pierre Lê-Bury
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Autoimmune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT), 18 route du Panorama, 92260 Fontenay-aux-Roses, France
| | - Hebert Echenique-Rivera
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
| | - Javier Pizarro-Cerdá
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
- Institut Pasteur, Université Paris Cité, Yersinia National Reference Laboratory, WHO Collaborating Research & Reference Centre for Plague FRA-146, 28 rue du Dr Roux, 75015 Paris, France
| | - Olivier Dussurget
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
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Mytych JS, Pan Z, Lopez-Davis C, Redinger N, Lawrence C, Ziegler J, Popescu NI, James JA, Farris AD. Peptidoglycan from Bacillus anthracis Inhibits Human Macrophage Efferocytosis in Part by Reducing Cell Surface Expression of MERTK and TIM-3. Immunohorizons 2024; 8:269-280. [PMID: 38517345 PMCID: PMC10985058 DOI: 10.4049/immunohorizons.2300109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 02/06/2024] [Indexed: 03/23/2024] Open
Abstract
Bacillus anthracis peptidoglycan (PGN) is a major component of the bacterial cell wall and a key pathogen-associated molecular pattern contributing to anthrax pathology, including organ dysfunction and coagulopathy. Increases in apoptotic leukocytes are a late-stage feature of anthrax and sepsis, suggesting there is a defect in apoptotic clearance. In this study, we tested the hypothesis that B. anthracis PGN inhibits the capacity of human monocyte-derived macrophages (MΦ) to efferocytose apoptotic cells. Exposure of CD163+CD206+ MΦ to PGN for 24 h impaired efferocytosis in a manner dependent on human serum opsonins but independent of complement component C3. PGN treatment reduced cell surface expression of the proefferocytic signaling receptors MERTK, TYRO3, AXL, integrin αVβ5, CD36, and TIM-3, whereas TIM-1, αVβ3, CD300b, CD300f, STABILIN-1, and STABILIN-2 were unaffected. ADAM17 is a major membrane-bound protease implicated in mediating efferocytotic receptor cleavage. We found multiple ADAM17-mediated substrates increased in PGN-treated supernatant, suggesting involvement of membrane-bound proteases. ADAM17 inhibitors TAPI-0 and Marimastat prevented TNF release, indicating effective protease inhibition, and modestly increased cell-surface levels of MerTK and TIM-3 but only partially restored efferocytic capacity by PGN-treated MΦ. We conclude that human serum factors are required for optimal recognition of PGN by human MΦ and that B. anthracis PGN inhibits efferocytosis in part by reducing cell surface expression of MERTK and TIM-3.
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Affiliation(s)
- Joshua S. Mytych
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Zijian Pan
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Charmaine Lopez-Davis
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Nancy Redinger
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Christina Lawrence
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Jadith Ziegler
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Narcis I. Popescu
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Judith A. James
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - A. Darise Farris
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
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Mytych JS, Pan Z, Lopez-Davis C, Redinger N, Lawrence C, Ziegler J, Popescu NI, James JA, Farris AD. Peptidoglycan from Bacillus anthracis Inhibits Human Macrophage Efferocytosis in Part by Reducing Cell Surface Expression of MERTK and TIM-3. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.30.535001. [PMID: 37066181 PMCID: PMC10103956 DOI: 10.1101/2023.03.30.535001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Bacillus anthracis peptidoglycan (PGN) is a major component of the bacterial cell wall and a key pathogen-associated molecular pattern (PAMP) contributing to anthrax pathology, including organ dysfunction and coagulopathy. Increases in apoptotic lymphocytes are a late-stage feature of anthrax and sepsis, suggesting there is a defect in apoptotic clearance. Here, we tested the hypothesis that B. anthracis PGN inhibits the capacity of human monocyte-derived macrophages (MΦ) to efferocytose apoptotic cells. Exposure of CD163+CD206+ MΦ to PGN for 24h impaired efferocytosis in a manner dependent on human serum opsonins but independent of complement component C3. PGN treatment reduced cell surface expression of the pro-efferocytic signaling receptors MERTK, TYRO3, AXL, integrin αVβ5, CD36 and TIM-3, whereas TIM-1, αVβ3, CD300b, CD300f, STABILIN-1 and STABILIN-2 were unaffected. ADAM17 is a major membrane-bound protease implicated in mediating efferocytotic receptor cleavage. We found multiple ADAM17-mediated substrates increased in PGN-treated supernatant suggesting involvement of membrane-bound proteases. ADAM17 inhibitors TAPI-0 and Marimastat prevented TNF release, indicating effective protease inhibition, and modestly increased cell-surface levels of MerTK and TIM-3 but only partially restored efferocytic capacity by PGN-treated MΦ. We conclude that human serum factors are required for optimal recognition of PGN by human MΦ and that B. anthracis PGN inhibits efferocytosis in part by reducing cell surface expression of MERTK and TIM-3.
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Affiliation(s)
- Joshua S Mytych
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, 825 NE 13 Street, Oklahoma City, OK 73104, USA
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, 1100 N Lindsay Avenue, Oklahoma City, OK 73104, USA
| | - Zijian Pan
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, 825 NE 13 Street, Oklahoma City, OK 73104, USA
| | - Charmaine Lopez-Davis
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, 825 NE 13 Street, Oklahoma City, OK 73104, USA
| | - Nancy Redinger
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, 825 NE 13 Street, Oklahoma City, OK 73104, USA
| | - Christina Lawrence
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, 825 NE 13 Street, Oklahoma City, OK 73104, USA
| | - Jadith Ziegler
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, 825 NE 13 Street, Oklahoma City, OK 73104, USA
| | - Narcis I. Popescu
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, 825 NE 13 Street, Oklahoma City, OK 73104, USA
| | - Judith A. James
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, 825 NE 13 Street, Oklahoma City, OK 73104, USA
| | - A. Darise Farris
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, 825 NE 13 Street, Oklahoma City, OK 73104, USA
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, 1100 N Lindsay Avenue, Oklahoma City, OK 73104, USA
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Internalization of Polymeric Bacterial Peptidoglycan Occurs through Either Actin or Dynamin Dependent Pathways. Microorganisms 2022; 10:microorganisms10030552. [PMID: 35336127 PMCID: PMC8951193 DOI: 10.3390/microorganisms10030552] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/28/2022] [Accepted: 02/28/2022] [Indexed: 01/27/2023] Open
Abstract
Peptidoglycan (PGN), a polymeric glycan macromolecule, is a major constituent of the bacterial cell wall and a conserved pathogen-associated molecular pattern (PAMP) that triggers immune responses through cytosolic sensors. Immune cells encounter both PGN polymers and hydrolyzed muropeptides during infections, and primary human innate immune cells respond better to polymeric PGN than the minimal bioactive subunit muramyl dipeptide (MDP). While MDP is internalized through macropinocytosis and/or clathrin-mediated endocytosis, the internalization of particulate polymeric PGN is unresolved. We show here that PGN macromolecules isolated from Bacillus anthracis display a broad range of sizes, making them amenable for multiple internalization pathways. Pharmacologic inhibition indicates that PGN primarily, but not exclusively, is internalized by actin-dependent endocytosis. An alternate clathrin-independent but dynamin dependent pathway supports 20–30% of PGN uptake. In primary monocytes, this alternate pathway does not require activities of RhoA, Cdc42 or Arf6 small GTPases. Selective inhibition of PGN uptake shows that phagolysosomal trafficking, processing and downstream immune responses are drastically affected by actin depolymerization, while dynamin inhibition has a smaller effect. Overall, we show that polymeric PGN internalization occurs through two endocytic pathways with distinct potentials to trigger immune responses.
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Complement C5 inhibition protects against hemolytic anemia and acute kidney injury in anthrax peptidoglycan-induced sepsis in baboons. Proc Natl Acad Sci U S A 2021; 118:2104347118. [PMID: 34507997 DOI: 10.1073/pnas.2104347118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2021] [Indexed: 01/20/2023] Open
Abstract
Late-stage anthrax infections are characterized by dysregulated immune responses and hematogenous spread of Bacillus anthracis, leading to extreme bacteremia, sepsis, multiple organ failure, and, ultimately, death. Despite the bacterium being nonhemolytic, some fulminant anthrax patients develop a secondary atypical hemolytic uremic syndrome (aHUS) through unknown mechanisms. We recapitulated the pathology in baboons challenged with cell wall peptidoglycan (PGN), a polymeric, pathogen-associated molecular pattern responsible for the hemostatic dysregulation in anthrax sepsis. Similar to aHUS anthrax patients, PGN induces an initial hematocrit elevation followed by progressive hemolytic anemia and associated renal failure. Etiologically, PGN induces erythrolysis through direct excessive activation of all three complement pathways. Blunting terminal complement activation with a C5 neutralizing peptide prevented the progressive deposition of membrane attack complexes on red blood cells (RBC) and subsequent intravascular hemolysis, heme cytotoxicity, and acute kidney injury. Importantly, C5 neutralization did not prevent immune recognition of PGN and shifted the systemic inflammatory responses, consistent with improved survival in sepsis. Whereas PGN-induced hemostatic dysregulation was unchanged, C5 inhibition augmented fibrinolysis and improved the thromboischemic resolution. Overall, our study identifies PGN-driven complement activation as the pathologic mechanism underlying hemolytic anemia in anthrax and likely other gram-positive infections in which PGN is abundantly represented. Neutralization of terminal complement reactions reduces the hemolytic uremic pathology induced by PGN and could alleviate heme cytotoxicity and its associated kidney failure in gram-positive infections.
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Couse Z, Cui X, Li Y, Moayeri M, Leppla S, Eichacker PQ. A Review of the Efficacy of FDA-Approved B. anthracis Anti-Toxin Agents When Combined with Antibiotic or Hemodynamic Support in Infection- or Toxin-Challenged Preclinical Models. Toxins (Basel) 2021; 13:53. [PMID: 33450877 PMCID: PMC7828353 DOI: 10.3390/toxins13010053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/05/2021] [Accepted: 01/09/2021] [Indexed: 12/29/2022] Open
Abstract
Anti-toxin agents for severe B. anthracis infection will only be effective if they add to the benefit of the two mainstays of septic shock management, antibiotic therapy and titrated hemodynamic support. Both of these standard therapies could negate benefits related to anti-toxin treatment. At present, three anthrax anti-toxin antibody preparations have received US Food and Drug Administration (FDA) approval: Raxibacumab, Anthrax Immune Globulin Intravenous (AIGIV) and ETI-204. Each agent is directed at the protective antigen component of lethal and edema toxin. All three agents were compared to placebo in antibiotic-treated animal models of live B. anthracis infection, and Raxibacumab and AIGIV were compared to placebo when combined with standard hemodynamic support in a 96 h canine model of anthrax toxin-associated shock. However, only AIG has actually been administered to a group of infected patients, and this experience was not controlled and offers little insight into the efficacy of the agents. To provide a broader view of the potential effectiveness of these agents, this review examines the controlled preclinical experience either in antibiotic-treated B. anthracis models or in titrated hemodynamic-supported toxin-challenged canines. The strength and weaknesses of these preclinical experiences are discussed.
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Affiliation(s)
- Zoe Couse
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA; (Z.C.); (X.C.); (Y.L.)
| | - Xizhong Cui
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA; (Z.C.); (X.C.); (Y.L.)
| | - Yan Li
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA; (Z.C.); (X.C.); (Y.L.)
| | - Mahtab Moayeri
- National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (M.M.); (S.L.)
| | - Stephen Leppla
- National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA; (M.M.); (S.L.)
| | - Peter Q. Eichacker
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA; (Z.C.); (X.C.); (Y.L.)
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Li Y, Cui X, Shiloach J, Wang J, Suffredini DA, Xu W, Liu W, Fitz Y, Sun J, Eichacker PQ. Hydrocortisone decreases lethality and inflammatory cytokine and nitric oxide production in rats challenged with B. anthracis cell wall peptidoglycan. Intensive Care Med Exp 2020; 8:67. [PMID: 33206255 PMCID: PMC7674536 DOI: 10.1186/s40635-020-00358-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 11/06/2020] [Indexed: 11/16/2022] Open
Abstract
Background Lethal B. anthracis infection produces high proinflammatory peptidoglycan (PGN) burdens in hosts. We investigated whether the lethality and inflammation anthrax PGN can produce are related. Methods At 6 h before and the start of 24 h anthrax PGN infusions, rats (n = 198) were treated with diluent (controls) or one of three IV-doses of either hydrocortisone (125, 12.5 or 1.25 mg/kg) or TNF-soluble receptor (TNFsr; 2000, 1000 or 333 μg/kg), non-selective and selective anti-inflammatory agents, respectively. Results Compared to controls, hydrocortisone 125 and 12.5 mg/kg each decreased 7-day lethality (p ≤ 0.004). Hydrocortisone 125 mg/kg decreased IL-1β, IL-6, TNFα, MCP, MIP-1α, MIP-2, RANTES and nitric oxide (NO) blood levels at 4 and 24 h after starting PGN (except MCP at 24 h). Each decrease was significant at 4 h (except MIP-1α that was significant at 24 h) (p ≤ 0.05). Similarly, hydrocortisone 12.5 mg/kg decreased each measure at 4, 24 and 48 h (except TNFα at 24 h and MIP-1α at 24 and 48 h and NO at 48 h). Decreases were significant for IL-6 and NO at 4 h and RANTES at 48 h (p ≤ 0.05). Hydrocortisone 1.25 mg/kg had non-significant effects. Each TNFsr dose decreased lethality but non-significantly. However, when doses were analyzed together, TNFsr decreased lethality in a potential trend (p = 0.16) and IL-6 and NO significantly at 4 h (p = 0.05). Conclusions Peptidoglycan-stimulated host inflammation may contribute to B. anthracis lethality.
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Affiliation(s)
- Yan Li
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Xizhong Cui
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Joseph Shiloach
- Biotechnology Core Laboratory, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jeffrey Wang
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Dante A Suffredini
- Section of Critical Care, Department of Medicine, St. Agnes Hospital, Baltimore, MD, 21229, USA
| | - Wanying Xu
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Wancang Liu
- Biotechnology Core Laboratory, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yvonne Fitz
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Junfeng Sun
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Peter Q Eichacker
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA.
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Monocyte procoagulant responses to anthrax peptidoglycan are reinforced by proinflammatory cytokine signaling. Blood Adv 2020; 3:2436-2447. [PMID: 31416821 DOI: 10.1182/bloodadvances.2019000513] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 06/17/2019] [Indexed: 01/03/2023] Open
Abstract
Disseminated intravascular coagulation is a frequent manifestation during bacterial infections and is associated with negative clinical outcomes. Imbalanced expression and activity of intravascular tissue factor (TF) is central to the development of infection-associated coagulopathies. Recently, we showed that anthrax peptidoglycan (PGN) induces disseminated intravascular coagulation in a nonhuman primate model of anthrax sepsis. We hypothesized that immune recognition of PGN by monocytes is critical for procoagulant responses to PGN and investigated whether and how PGN induces TF expression in primary human monocytes. We found that PGN induced monocyte TF expression in a large cohort of healthy volunteers similar to lipopolysaccharide stimulation. Both immune and procoagulant responses to PGN involve intracellular recognition after PGN internalization, as well as surface signaling through immune Fcγ receptors (FcγRs). In line with our hypothesis, blocking immune receptor function, both signaling and FcγR-mediated phagocytosis, significantly reduced but did not abolish PGN-induced monocyte TF expression, indicating that FcγR-independent internalization contributes to intracellular recognition of PGN. Conversely, when intracellular PGN recognition is abolished, TF expression was sensitive to inhibitors of FcγR signaling, indicating that surface engagement of monocyte immune receptors can promote TF expression. The primary procoagulant responses to PGN were further amplified by proinflammatory cytokines through paracrine and autocrine signaling. Despite intersubject variability in the study cohort, dual neutralization of tumor necrosis factor-α and interleukin-1β provided the most robust inhibition of the procoagulant amplification loop and may prove useful for reducing coagulopathies in gram-positive sepsis.
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Popescu NI, Keshari RS, Cochran J, Coggeshall KM, Lupu F. C3 Opsonization of Anthrax Bacterium and Peptidoglycan Supports Recognition and Activation of Neutrophils. Microorganisms 2020; 8:E1039. [PMID: 32668703 PMCID: PMC7409185 DOI: 10.3390/microorganisms8071039] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/08/2020] [Accepted: 07/11/2020] [Indexed: 12/01/2022] Open
Abstract
Neutrophils are the most abundant innate cell population and a key immune player against invading pathogens. Neutrophils can kill both bacterium and spores of Bacillus anthracis, the causative anthrax pathogen. Unlike interactions with professional phagocytes, the molecular recognition of anthrax by neutrophils is largely unknown. In this study, we investigated the role of complement C3 deposition on anthrax particles for neutrophil recognition of bacterium and/or its cell wall peptidoglycan, an abundant pathogen-associated molecular pattern that supports anthrax sepsis. C3 opsonization and recognition by complement receptors accounted for 70-80% of the affinity interactions between neutrophils and anthrax particles at subphysiologic temperatures. In contrast, C3 supported up to 50% of the anthrax particle ingestion under thermophysiologic conditions. Opsonin-dependent low affinity interactions and, to a lower extent, opsonin-independent mechanisms, provide alternative entry routes. Similarly, C3 supported 58% of peptidoglycan-induced degranulation and, to a lower extent, 23% of bacterium-induced degranulation. Interestingly, an opsonin independent mechanism mediated by complement C5, likely through C5a anaphylatoxin, primes azurophilic granules in response to anthrax particles. Overall, we show that C3 deposition supports anthrax recognition by neutrophils but is dispensable for pathogen ingestion and neutrophil degranulation, highlighting immune recognition redundancies that minimize the risk of pathogen evasion.
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Affiliation(s)
- Narcis I. Popescu
- Department of Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; (J.C.); (K.M.C.)
| | - Ravi S. Keshari
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA;
| | - Jackie Cochran
- Department of Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; (J.C.); (K.M.C.)
| | - K. Mark Coggeshall
- Department of Arthritis and Clinical Immunology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA; (J.C.); (K.M.C.)
| | - Florea Lupu
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA;
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Structural Integrity of the Alveolar-Capillary Barrier in Cynomolgus Monkeys Challenged with Fully Virulent and Toxin-Deficient Strains of Bacillus anthracis. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:2095-2110. [PMID: 32598882 DOI: 10.1016/j.ajpath.2020.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/27/2020] [Accepted: 06/09/2020] [Indexed: 11/21/2022]
Abstract
Inhalational anthrax, a disease caused by inhaling Bacillus anthracis spores, leads to respiratory distress, vascular leakage, high-level bacteremia, and often death within days. Anthrax lethal toxin and edema toxin, which are composed of protective antigen (PA) plus either lethal factor (LF) or edema factor (EF), respectively, play an important yet incompletely defined role in the pulmonary pathophysiology. To better understand their contribution, we examined the structural integrity of the alveolar-capillary barrier in archival formalin-fixed lungs of cynomolgus monkeys challenged with the fully virulent B. anthracis Ames wild-type strain or the isogenic toxin-deficient mutants ΔEF, ΔLF, and ΔPA. Pulmonary spore challenge with the wild-type strain caused high mortality, intra-alveolar hemorrhages, extensive alveolar septal sequestration of bacteria and neutrophils, diffuse destabilization of epithelial and endothelial junctions, increased markers of coagulation and complement activation (including tissue factor and C5a), and multifocal intra-alveolar fibrin deposition. ΔEF challenge was lethal and showed similar alveolar-capillary alterations; however, intra-alveolar hemorrhages, bacterial deposition, and markers of coagulation or complement were absent or markedly lower. In contrast, ΔLF or ΔPA challenges were nonlethal and showed no signs of alveolar bacterial deposition or alveolar-capillary changes. These findings provide evidence that lethal toxin plays a determinative role in bacterial dissemination and alveolar-capillary barrier dysfunction, and edema toxin may significantly exacerbate pulmonary pathologies in a systemic infection.
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Marchetti M, De Bei O, Bettati S, Campanini B, Kovachka S, Gianquinto E, Spyrakis F, Ronda L. Iron Metabolism at the Interface between Host and Pathogen: From Nutritional Immunity to Antibacterial Development. Int J Mol Sci 2020; 21:E2145. [PMID: 32245010 PMCID: PMC7139808 DOI: 10.3390/ijms21062145] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 02/08/2023] Open
Abstract
Nutritional immunity is a form of innate immunity widespread in both vertebrates and invertebrates. The term refers to a rich repertoire of mechanisms set up by the host to inhibit bacterial proliferation by sequestering trace minerals (mainly iron, but also zinc and manganese). This strategy, selected by evolution, represents an effective front-line defense against pathogens and has thus inspired the exploitation of iron restriction in the development of innovative antimicrobials or enhancers of antimicrobial therapy. This review focuses on the mechanisms of nutritional immunity, the strategies adopted by opportunistic human pathogen Staphylococcus aureus to circumvent it, and the impact of deletion mutants on the fitness, infectivity, and persistence inside the host. This information finally converges in an overview of the current development of inhibitors targeting the different stages of iron uptake, an as-yet unexploited target in the field of antistaphylococcal drug discovery.
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Affiliation(s)
- Marialaura Marchetti
- Interdepartmental Center Biopharmanet-TEC, University of Parma, 43124 Parma, Italy; (M.M.); (S.B.)
| | - Omar De Bei
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (O.D.B.); (B.C.)
| | - Stefano Bettati
- Interdepartmental Center Biopharmanet-TEC, University of Parma, 43124 Parma, Italy; (M.M.); (S.B.)
- Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy
- Institute of Biophysics, National Research Council, 56124 Pisa, Italy
- National Institute of Biostructures and Biosystems, 00136 Rome, Italy
| | - Barbara Campanini
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (O.D.B.); (B.C.)
| | - Sandra Kovachka
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (S.K.); (E.G.); (F.S.)
| | - Eleonora Gianquinto
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (S.K.); (E.G.); (F.S.)
| | - Francesca Spyrakis
- Department of Drug Science and Technology, University of Turin, 10125 Turin, Italy; (S.K.); (E.G.); (F.S.)
| | - Luca Ronda
- Interdepartmental Center Biopharmanet-TEC, University of Parma, 43124 Parma, Italy; (M.M.); (S.B.)
- Department of Medicine and Surgery, University of Parma, 43126 Parma, Italy
- Institute of Biophysics, National Research Council, 56124 Pisa, Italy
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Popescu NI, Silasi R, Keshari RS, Girton A, Burgett T, Zeerleder SS, Gailani D, Gruber A, Lupu F, Coggeshall KM. Peptidoglycan induces disseminated intravascular coagulation in baboons through activation of both coagulation pathways. Blood 2018; 132:849-860. [PMID: 29921614 PMCID: PMC6107880 DOI: 10.1182/blood-2017-10-813618] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 06/14/2018] [Indexed: 12/13/2022] Open
Abstract
Anthrax infections exhibit progressive coagulopathies that may contribute to the sepsis pathophysiology observed in fulminant disease. The hemostatic imbalance is recapitulated in primate models of late-stage disease but is uncommon in toxemic models, suggesting contribution of other bacterial pathogen-associated molecular patterns (PAMPs). Peptidoglycan (PGN) is a bacterial PAMP that engages cellular components at the cross talk between innate immunity and hemostasis. We hypothesized that PGN is critical for anthrax-induced coagulopathies and investigated the activation of blood coagulation in response to a sterile PGN infusion in primates. The PGN challenge, like the vegetative bacteria, induced a sepsis-like pathophysiology characterized by systemic inflammation, disseminated intravascular coagulation (DIC), organ dysfunction, and impaired survival. Importantly, the hemostatic impairment occurred early and in parallel with the inflammatory response, suggesting direct engagement of coagulation pathways. PGN infusion in baboons promoted early activation of contact factors evidenced by elevated protease-serpin complexes. Despite binding to contact factors, PGN did not directly activate either factor XII (FXII) or prekallikrein. PGN supported contact coagulation by enhancing enzymatic function of active FXII (FXIIa) and depressing its inhibition by antithrombin. In parallel, PGN induced de novo monocyte tissue factor expression in vitro and in vivo, promoting extrinsic clotting reactions at later stages. Activation of platelets further amplified the procoagulant state during PGN challenge, leading to DIC and subsequent ischemic damage of peripheral tissues. These data indicate that PGN may be a major cause for the pathophysiologic progression of Bacillus anthracis sepsis and is the primary PAMP behind the pathogen-induced coagulopathy in late-stage anthrax.
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Affiliation(s)
| | - Robert Silasi
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Ravi S Keshari
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Alanson Girton
- Department of Arthritis and Clinical Immunology and
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | | | - Sacha S Zeerleder
- Department of Hematology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Department of Immunopathology, Sanquin Research, Amsterdam, The Netherlands
| | - David Gailani
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN; and
| | - Andras Gruber
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR
| | - Florea Lupu
- Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - K Mark Coggeshall
- Department of Arthritis and Clinical Immunology and
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
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Serum Amyloid P and IgG Exhibit Differential Capabilities in the Activation of the Innate Immune System in Response to Bacillus anthracis Peptidoglycan. Infect Immun 2018. [PMID: 29531132 PMCID: PMC5913848 DOI: 10.1128/iai.00076-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
We showed that human IgG supported the response by human innate immune cells to peptidoglycan (PGN) from Bacillus anthracis and PGN-induced complement activation. However, other serum constituents have been shown to interact with peptidoglycan, including the IgG-like soluble pattern recognition receptor serum amyloid P (SAP). Here, we compared the abilities of SAP and of IgG to support monocyte and complement responses to PGN. Utilizing in vitro methods, we demonstrate that SAP is superior to IgG in supporting monocyte production of cytokines in response to PGN. Like IgG, the response supported by SAP was enhanced by phagocytosis and signaling kinases, such as Syk, Src, and phosphatidylinositol 3-kinase, that are involved in various cellular processes, including Fc receptor signaling. Unlike IgG, SAP had no effect on the activation of complement in response to PGN. These data demonstrate an opsonophagocytic role for SAP in response to PGN that propagates a cellular response without propagating the formation of the terminal complement complex.
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Jeon JH, Park DB, Woo SJ, Lee HR, Park OK, Park J, Rhie GE. Muramyl dipeptide potentiates a Bacillus anthracis poly-γ-d-glutamic acid capsule surrogate that induces maturation and activation of mouse dendritic cells. Cytokine 2018; 110:350-356. [PMID: 29656957 DOI: 10.1016/j.cyto.2018.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 03/29/2018] [Accepted: 04/04/2018] [Indexed: 12/28/2022]
Abstract
Poly-γ-d-glutamic acid (PGA) of anthrax is an important pathogenic factor due to its anti-phagocytic activity. Additionally, PGA has the ability to activate mouse macrophages for the secretion of cytokines through Toll-like receptor (TLR) 2. Peptidoglycan (PGN), a major bacterial cell-wall component, induces inflammatory responses in the host. We assessed whether PGA can induce maturation and cytokine expression in immature mouse dendritic cells (DCs) in the existence of muramyl dipeptide (MDP), the minimum motif of PGN with immunostimulatory activity. Stimulation of immature DCs with PGA or MDP alone augmented expression of costimulatory molecules and MHC class II proteins, which are all cell surface markers indicative of maturation. The observed effects were further enhanced by costimulation of PGA and MDP. PGA alone was sufficient to induce expression of TNF-α, IL-6, MCP-1, and MIP1-α, whereas MDP alone did not under the same conditions. Treatment with MDP enhanced PGA-induced expression of the tested inflammatory mediators; however, the synergistic effect found for PGA and MDP was not observed in TLR2- or nucleotide-binding oligomerization domain (NOD) 2-knockout DCs. Additionally, MDP augmented PGA-induced MAP kinases and NF-κB activation, which is crucial for expression of cytokines. Furthermore, MAP kinase and NF-κB inhibitors attenuated MDP enhancement of PGA-induced cytokine production. In addition, co-culture of splenocytes and PGA/MDP-matured DCs induced higher expression of IL-2 and IFN-γ compared to that of splenocytes and PGA-matured DCs. Collectively, our results suggest that PGA and MDP cooperatively induce inflammatory responses in mouse DCs through TLR2 and NOD2 via MAP kinase and NF-κB pathways, subsequently leading to lymphocyte activation.
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Affiliation(s)
- Jun Ho Jeon
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Republic of Korea
| | - Deok-Bum Park
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Republic of Korea
| | - Sun-Je Woo
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Republic of Korea
| | - Hae-Ri Lee
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Republic of Korea
| | - Ok-Kyu Park
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Republic of Korea
| | - Jungchan Park
- Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yongin 17035, Republic of Korea; Protein Research Center for Bioindustry, Hankuk University of Foreign Studies, Yongin 17035, Republic of Korea
| | - Gi-Eun Rhie
- Division of High-risk Pathogens, Center for Laboratory Control of Infectious Diseases, Korea Centers for Disease Control and Prevention, Republic of Korea.
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Langer M, Girton AW, Popescu NI, Burgett T, Metcalf JP, Coggeshall KM. Neither Lys- and DAP-type peptidoglycans stimulate mouse or human innate immune cells via Toll-like receptor 2. PLoS One 2018; 13:e0193207. [PMID: 29474374 PMCID: PMC5825070 DOI: 10.1371/journal.pone.0193207] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/06/2018] [Indexed: 11/18/2022] Open
Abstract
Peptidoglycan (PGN), a major component of bacterial cell walls, is a pathogen-associated molecular pattern (PAMP) that causes innate immune cells to produce inflammatory cytokines that escalate the host response during infection. In order to better understand the role of PGN in infection, we wanted to gain insight into the cellular receptor for PGN. Although the receptor was initially identified as Toll-like receptor 2 (TLR2), this receptor has remained controversial and other PGN receptors have been reported. We produced PGN from live cultures of Bacillus anthracis and Staphylococcus aureus and tested samples of PGN isolated during the purification process to determine at what point TLR2 activity was removed, if at all. Our results indicate that although live B. anthracis and S. aureus express abundant TLR2 ligands, highly-purified PGN from either bacterial source is not recognized by TLR2.
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Affiliation(s)
- Marybeth Langer
- The Oklahoma Medical Research Foundation, Program in Arthritis & Immunology, Oklahoma City, OK, United States of America
| | - Alanson W. Girton
- The Oklahoma Medical Research Foundation, Program in Arthritis & Immunology, Oklahoma City, OK, United States of America
- The Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America
| | - Narcis I. Popescu
- The Oklahoma Medical Research Foundation, Program in Arthritis & Immunology, Oklahoma City, OK, United States of America
| | - Tarea Burgett
- The Oklahoma Medical Research Foundation, Program in Arthritis & Immunology, Oklahoma City, OK, United States of America
| | - Jordan P. Metcalf
- The Department of Medicine, Pulmonary and Critical Care Div., University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America
| | - K. Mark Coggeshall
- The Oklahoma Medical Research Foundation, Program in Arthritis & Immunology, Oklahoma City, OK, United States of America
- The Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America
- * E-mail:
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Xu W, Ohanjandian L, Sun J, Cui X, Suffredini D, Li Y, Welsh J, Eichacker PQ. A systematic review and meta-analysis of preclinical trials testing anti-toxin therapies for B. anthracis infection: A need for more robust study designs and results. PLoS One 2017; 12:e0182879. [PMID: 28797061 PMCID: PMC5552191 DOI: 10.1371/journal.pone.0182879] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 07/26/2017] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND B. anthracis anti-toxin agents are approved and included in the Strategic National Stockpile based primarily on animal infection trials. However, in the only anthrax outbreak an approved anti-toxin agent was administered in, survival did not differ comparing recipients and non-recipients, although recipients appeared sicker. OBJECTIVE Employ a systematic review and meta-analysis to investigate preclinical studies supporting anthrax anti-toxin agents. DATA SOURCE PubMed, EMBASE, and Scopus. STUDY ELIGIBILITY Compared survival with an anti-toxin agent versus control in B. anthracis challenged, antibiotic treated animals. STUDY METHODS Examine model and study design and the effect of anti-toxin agents on relative risk of death(95%CI) (RR). RESULTS From 9 studies, 29 experiments were analyzed which included 4 species (748 animals) and 5 agents; LFI, AIG, AVP-21D9, Raxibacumab, and ETI-204. Only five experiments were blinded and no experiment included the cardiopulmonary support sick B. anthracis patients receive. Only one agent in a single un-blinded experiment reduced RR significantly [0.45(0.22,0.940]. However, in six studies testing an agent in more than one experiment in the same species, agents had consistent survival effects across experiments [I2 = 0, p≥0.55 in five and I2 = 42%, p = 0.16 in one]. Within each species, agents had effects on the side of benefit; in one study testing AVP-21D9 in mice [0.11(0.01,1.82)] or guinea pigs [0.70(0.48,1.03)]; across eight rabbit studies testing LFI, Raxibacumab, AIG or ETI-204 [0.62(0.45,0.87); I2 = 17.4%, p = 0.29]; and across three monkey studies testing Raxibacumab, AIG or ETI-204 [0.66(0.34,1.27); I2 = 25.3%, p = 0.26]. Across all agents and species, agents decreased RR [0.64(0.52,0.79); I2 = 5.3%, p = 0.39]. LIMITATIONS Incidence of selective reporting not identifiable. CONCLUSIONS Although overall significant, individually anti-toxin agents had weak beneficial effects. Lack of study blinding and relevant clinical therapies further weakened studies. Although difficult, preclinical studies with more robust designs and results are warranted to justify the resources necessary to maintain anti-toxin agents in national stockpiles.
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Affiliation(s)
- Wanying Xu
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Lernik Ohanjandian
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Junfeng Sun
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Xizhong Cui
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Dante Suffredini
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yan Li
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Judith Welsh
- National Institutes of Health Library, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Peter Q. Eichacker
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Bacillus anthracis Edema Toxin Increases Fractional Free Water and Sodium Reabsorption in an Isolated Perfused Rat Kidney Model. Infect Immun 2017; 85:IAI.00264-17. [PMID: 28438974 DOI: 10.1128/iai.00264-17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 04/13/2017] [Indexed: 11/20/2022] Open
Abstract
Bacillus anthracis edema toxin (ET) consists of protective antigen (PA), necessary for host cell toxin uptake, and edema factor (EF), the toxic moiety which increases host cell cyclic AMP (cAMP). Since vasopressin stimulates renal water and sodium reabsorption via increased tubular cell cAMP levels, we hypothesized the ET would also do so. To test this hypothesis, we employed an isolated perfused rat kidney model. Kidneys were isolated and perfused with modified Krebs-Henseleit buffer. Perfusate and urine samples were obtained at baseline and every 10 min over 150 min following the addition of challenges with or without treatments to the perfusate. In kidneys perfused under constant flow or constant pressure, compared to PA challenge (n = 14 or 15 kidneys, respectively), ET (13 or 15 kidneys, respectively) progressively increased urine cAMP levels, water and sodium reabsorption, and urine osmolality and decreased urine output (P ≤ 0.04, except for sodium reabsorption under constant pressure [P = 0.17]). In ET-challenged kidneys, compared to placebo treatment, adefovir, an EF inhibitor, decreased urine cAMP levels, water and sodium reabsorption, and urine osmolality and increased urine output, while raxibacumab, a PA-directed monoclonal antibody (MAb), decreased urine cAMP levels, free water reabsorption, and urine osmolality and increased urine output (P ≤ 0.03 except for urine output with raxibacumab [P = 0.17]). Upon immunohistochemistry, aquaporin 2 was concentrated along the apical membrane of tubular cells with ET but not PA, and urine aquaporin 2 levels were higher with ET (5.52 ± 1.06 ng/ml versus 1.51 ± 0.44 ng/ml [means ± standard errors of the means {SEM}; P = 0.0001). Edema toxin has renal effects that could contribute to extravascular fluid collection characterizing anthrax infection clinically.
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18
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Li Y, Cui X, Xu W, Ohanjanian L, Sampath-Kumar H, Suffredini D, Moayeri M, Leppla S, Fitz Y, Eichacker PQ. Nitric oxide production contributes to Bacillus anthracis edema toxin-associated arterial hypotension and lethality: ex vivo and in vivo studies in the rat. Am J Physiol Heart Circ Physiol 2016; 311:H781-93. [PMID: 27448553 DOI: 10.1152/ajpheart.00163.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 07/19/2016] [Indexed: 01/26/2023]
Abstract
We showed previously that Bacillus anthracis edema toxin (ET), comprised of protective antigen (PA) and edema factor (EF), inhibits phenylephrine (PE)-induced contraction in rat aortic rings and these effects are diminished in endothelial-denuded rings. Therefore, employing rat aortic ring and in vivo models, we tested the hypothesis that nitric oxide (NO) contributes to ET's arterial effects. Compared with rings challenged with PA alone, ET (PA + EF) reduced PE-stimulated maximal contractile force (MCF) and increased the PE concentration producing 50% MCF (EC50) (P < 0.0001). Compared with placebo, l-nitro-arginine methyl-ester (l-NAME), an NO synthase (NOS) inhibitor, reduced ET's effects on MCF and EC50 in patterns that approached or were significant (P = 0.06 and 0.03, respectively). In animals challenged with 24-h ET infusions, l-NAME (0.5 or 1.0 mg·kg(-1)·h(-1)) coadministration increased survival to 17 of 28 animals (60.7%) compared with 4 of 27 (14.8%) given placebo (P = 0.01). Animals receiving l-NAME but no ET all survived. Compared with PBS challenge, ET increased NO levels at 24 h and l-NAME decreased these increases (P < 0.0001). ET infusion decreased mean arterial blood pressure (MAP) in placebo and l-NAME-treated animals (P < 0.0001) but l-NAME reduced decreases in MAP with ET from 9 to 24 h (P = 0.03 for the time interaction). S-methyl-l-thiocitrulline, a selective neuronal NOS inhibitor, had effects in rings and, at a high dose in vivo models, comparable to l-NAME, whereas N'-[3-(aminomethyl)benzyl]-acetimidamide, a selective inducible NOS inhibitor, did not. NO production contributes to ET's arterial relaxant, hypotensive, and lethal effects in the rat.
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Affiliation(s)
- Yan Li
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Xizhong Cui
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Wanying Xu
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Lernik Ohanjanian
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Hanish Sampath-Kumar
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Dante Suffredini
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Mahtab Moayeri
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Stephen Leppla
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Yvonne Fitz
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
| | - Peter Q Eichacker
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland; and
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Booth M, Donaldson L, Cui X, Sun J, Cole S, Dailsey S, Hart A, Johns N, McConnell P, McLennan T, Parcell B, Robb H, Shippey B, Sim M, Wallis C, Eichacker PQ. Confirmed Bacillus anthracis infection among persons who inject drugs, Scotland, 2009-2010. Emerg Infect Dis 2015; 20:1452-63. [PMID: 25148307 PMCID: PMC4178387 DOI: 10.3201/eid2009.131481] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Patients who died had an increased sequential organ failure assessment score and need for vasopressors.
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20
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Sun DS, Lee PC, Kau JH, Shih YL, Huang HH, Li CR, Lee CC, Wu YP, Chen KC, Chang HH. Acquired coagulant factor VIII deficiency induced by Bacillus anthracis lethal toxin in mice. Virulence 2015; 6:466-75. [PMID: 25906166 DOI: 10.1080/21505594.2015.1031454] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Mice treated with anthrax lethal toxin (LT) exhibit hemorrhage caused by unknown mechanisms. Moreover, LT treatment in mice induced liver damage. In this study, we hypothesized that a suppressed coagulation function may be associated with liver damage, because the liver is the major producing source of coagulation factors. The hepatic expression of coagulant factors and the survival rates were analyzed after cultured cells or mice were exposed to LT. In agreement with our hypothesis, LT induces cytotoxicity against hepatic cells in vitro. In addition, suppressed expression of coagulation factor VIII (FVIII) in the liver is associated with a prolonged plasma clotting time in LT-treated mice, suggesting a suppressive role of LT in coagulation. Accordingly, we further hypothesized that a loss-of-function approach involving treatments of an anticoagulant should exacerbate LT-induced abnormalities, whereas a gain-of-function approach involving injections of recombinant FVIII to complement the coagulation deficiency should ameliorate the pathogenesis. As expected, a sublethal dose of LT caused mortality in the mice that were non-lethally pretreated with an anticoagulant (warfarin). By contrast, treatments of recombinant FVIII reduced the mortality from a lethal dose of LT in mice. Our results indicated that LT-induced deficiency of FVIII is involved in LT-mediated pathogenesis. Using recombinant FVIII to correct the coagulant defect may enable developing a new strategy to treat anthrax.
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Affiliation(s)
- Der-Shan Sun
- a Department of Molecular Biology and Human Genetics; Tzu-Chi University ; Hualien , Taiwan
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Xu X, Hicks C, Li Y, Su J, Shiloach J, Kaufman JB, Fitz Y, Eichacker PQ, Cui X. Purified cell wall from the probiotic bacterium Lactobacillus gasseri activates systemic inflammation and, at higher doses, produces lethality in a rat model. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:R140. [PMID: 24989885 PMCID: PMC4226968 DOI: 10.1186/cc13966] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 05/13/2014] [Indexed: 12/16/2022]
Abstract
Introduction One proposed benefit of probiotic therapy is that probiotic bacterial cell-wall binding to intestinal cell pathogen-recognition receptors activates protective innate immunity. However, in critically ill patients, intestinal epithelium disruption by shock or other insults may compromise this compartmentalized response and cause systemic bacteria and cell-wall translocation. The effects of intravascular introduction of probiotic bacterial cell wall are unclear. Methods We investigated 24-hour infusions of purified cell wall from Lactobacillus gasseri ATC33323 (L. gasseri), a probiotic bacterium, in Sprague–Dawley rats (n = 49). Results Increasing cell-wall doses (0 (control), 10, 20, 40, 80, or 160 mg/kg over 24 hours) produced dose-ordered decreases in survival measured after 168 hours (11 survivors/11 total (100%), seven of seven (100%), seven of seven (100%), six of eight (75%), five of eight (63%), and one of nine (11%), respectively, P < 0.0001). The L. gasseri cell wall was equally or more lethal than Staphylococcus aureus cell wall, which was previously studied (100% to 88% survival with the same increasing doses). During challenge, compared with controls, L. gasseri cell wall produced increases in blood IL-1β, IL-10, tumor necrosis factor-α, migratory inhibitory protein-1α, monocyte chemotactic protein-1, and nitric oxide, and decreases in neutrophils, lymphocytes, and platelets that were greater with higher versus lower doses (P ≤ 0.05). Medium-dose cell wall (40 and 80 mg/kg combined) progressively decreased blood pressure and increased heart rate, and all doses increased lactate, hepatic transaminases, and creatinine phosphokinase (P ≤ 0.05). Conclusion Although L. gasseri, like other probiotic bacteria, is considered safe, its cell wall can stimulate the maladaptive inflammatory response associated with pathogenic bacteria. Such effects deserve study, especially regarding critically ill patients.
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Adamo R. Glycan surface antigens fromBacillus anthracisas vaccine targets: current status and future perspectives. Expert Rev Vaccines 2014; 13:895-907. [DOI: 10.1586/14760584.2014.924404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Brojatsch J, Casadevall A, Goldman DL. Molecular determinants for a cardiovascular collapse in anthrax. Front Biosci (Elite Ed) 2014; 6:139-47. [PMID: 24389148 DOI: 10.2741/e697] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Bacillus anthracis releases two bipartite proteins, lethal toxin and edema factor, that contribute significantly to the progression of anthrax-associated shock. As blocking the anthrax toxins prevents disease, the toxins are considered the main virulence factors of the bacterium. The anthrax bacterium and the anthrax toxins trigger multi-organ failure associated with enhanced vascular permeability, hemorrhage and cardiac dysfunction in animal challenge models. A recent study using mice that either lacked the anthrax toxin receptor in specific cells and corresponding mice expressing the receptor in specific cell types demonstrated that cardiovascular cells are critical for disease mediated by anthrax lethal toxin. These studies are consistent with involvement of the cardiovascular system, and with an increase of cardiac failure markers observed in human anthrax and in animal models using B. anthracis and anthrax toxins. This review discusses the current state of knowledge regarding the pathophysiology of anthrax and tries to provide a mechanistic model and molecular determinants for the circulatory shock in anthrax.
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Affiliation(s)
- Jurgen Brojatsch
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY
| | - Arturo Casadevall
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY
| | - David L Goldman
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY
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Remy KE, Qiu P, Li Y, Cui X, Eichacker PQ. B. anthracis associated cardiovascular dysfunction and shock: the potential contribution of both non-toxin and toxin components. BMC Med 2013; 11:217. [PMID: 24107194 PMCID: PMC3851549 DOI: 10.1186/1741-7015-11-217] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 09/13/2013] [Indexed: 01/31/2023] Open
Abstract
The development of cardiovascular dysfunction and shock in patients with invasive Bacillus anthracis infection has a particularly poor prognosis. Growing evidence indicates that several bacterial components likely play important pathogenic roles in this injury. As with other pathogenic Gram-positive bacteria, the B. anthracis cell wall and its peptidoglycan constituent produce a robust inflammatory response with its attendant tissue injury, disseminated intravascular coagulation and shock. However, B. anthracis also produces lethal and edema toxins that both contribute to shock. Growing evidence suggests that lethal toxin, a metalloprotease, can interfere with endothelial barrier function as well as produce myocardial dysfunction. Edema toxin has potent adenyl cyclase activity and may alter endothelial function, as well as produce direct arterial and venous relaxation. Furthermore, both toxins can weaken host defense and promote infection. Finally, B. anthracis produces non-toxin metalloproteases which new studies show can contribute to tissue injury, coagulopathy and shock. In the future, an understanding of the individual pathogenic effects of these different components and their interactions will be important for improving the management of B. anthracis infection and shock.
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Affiliation(s)
- Kenneth E Remy
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
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Li Y, Cui X, Solomon SB, Remy K, Fitz Y, Eichacker PQ. B. anthracis edema toxin increases cAMP levels and inhibits phenylephrine-stimulated contraction in a rat aortic ring model. Am J Physiol Heart Circ Physiol 2013; 305:H238-50. [PMID: 23585140 DOI: 10.1152/ajpheart.00185.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
B. anthracis edema toxin (ET) and lethal toxin (LT) are each composed of protective antigen (PA), necessary for toxin uptake by host cells, and their respective toxic moieties, edema factor (EF) and lethal factor (LF). Although both toxins likely contribute to shock during infection, their mechanisms are unclear. To test whether ET and LT produce arterial relaxation, their effects on phenylephrine (PE)-stimulated contraction in a Sprague-Dawley rat aortic ring model were measured. Rings were prepared and connected to pressure transducers. Their viability was confirmed, and peak contraction with 60 mM KCl was determined. Compared with PA pretreatment (control, 60 min), ET pretreatment at concentrations similar to those noted in vivo decreased the mean (±SE) maximum contractile force (MCF; percent peak contraction) in rings generated during stimulation with increasing PE concentrations (96.2 ± 7.0 vs. 57.3 ± 9.1) and increased the estimated PE concentration producing half the MCF (EC50; 10(-7) M, 1.1 ± 0.3 vs. 3.7 ± 0.8, P ≤ 0.002). ET inhibition with PA-directed monoclonal antibodies, selective EF inhibition with adefovir, or removal of the ring endothelium inhibited the effects of ET on MCF and EC50 (P ≤ 0.02). Consistent with its adenyl cyclase activity, ET increased tissue cAMP in endothelium-intact but not endothelium-denuded rings (P < 0.0001 and 0.25, respectively). LT pretreatment, even in high concentrations, did not significantly decrease MCF or increase EC50 (all P > 0.05). In rings precontracted with PE compared with posttreatment with PA (90 min), ET posttreatment produced progressive reductions in contractile force and increases in relaxation in endothelium-intact rings (P < 0.0001) but not endothelium-denuded rings (P = 0.51). Thus, ET may contribute to shock by producing arterial relaxation.
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Affiliation(s)
- Yan Li
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
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