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Khan H, Bhargava V, Elkins KL. Francisella tularensis Live Vaccine Strain training of murine alveolar and bone marrow-derived macrophages. Microbiol Spectr 2024:e0002824. [PMID: 38940590 DOI: 10.1128/spectrum.00028-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 05/28/2024] [Indexed: 06/29/2024] Open
Abstract
Traditionally, successful vaccines rely on specific adaptive immunity by activating lymphocytes with an attenuated pathogen, or pathogen subunit, to elicit heightened responses upon subsequent exposures. However, recent work with Mycobacterium tuberculosis and other pathogens has identified a role for "trained" monocytes in protection through memory-like but non-specific immunity. Here, we used an in vitro co-culture approach to study the potential role of trained macrophages, including lung alveolar macrophages, in immune responses to the Live Vaccine Strain (LVS) of Francisella tularensis. F. tularensis is an intracellular bacterium that replicates within mammalian macrophages and causes respiratory as well as systemic disease. We vaccinated mice with F. tularensis LVS and then obtained lung alveolar macrophages, or derived macrophages from bone marrow. LVS infected and replicated comparably in both types of macrophages, whether naïve or from LVS-vaccinated mice. LVS-infected macrophages were then co-cultured with either naïve splenocytes, splenocytes from mice vaccinated intradermally, or splenocytes from mice vaccinated intravenously. For the first time, we show that immune (but not naïve) splenocytes controlled bacterial replication within alveolar macrophages, similar to previous results using bone marrow-derived macrophage. However, no differences in control of intramacrophage bacterial replication were found between co-cultures with naïve macrophages or macrophages from LVS-vaccinated mice; furthermore, nitric oxide levels and interferon-gamma production in supernatants were largely comparable across all conditions. Thus, in the context of in vitro co-cultures, the data do not support development of trained macrophages in bone marrow or lungs of mice vaccinated with LVS intradermally or intravenously. IMPORTANCE The discovery of non-specific "trained immunity" in monocytes has generated substantial excitement. However, to date, training has been studied with relatively few microbes (e.g., Mycobacterium bovis Bacille Calmette-Guérin, a live attenuated intracellular bacterium used as a vaccine) and microbial substances (e.g., LPS), and it remains unclear whether training during infection is common. We previously demonstrated that vaccination of mice with Francisella tularensis Live Vaccine Strain (LVS), another live attenuated intracellular bacterium, protected against challenge with the unrelated bacterium Listeria monocytogenes. The present study therefore tested whether LVS vaccination engenders trained macrophages that contributed to this protection. To do so, we used a previous in vitro co-culture approach with murine bone marrow-derived macrophages to expand and study lung alveolar macrophages. We demonstrated that alveolar macrophages can be productively infected and employed to characterize interactions with LVS-immune lymphocytes. However, we find no evidence that either bone marrow-derived or alveolar macrophages are trained by LVS vaccination.
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Affiliation(s)
- Hamda Khan
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Varunika Bhargava
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Karen L Elkins
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA
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2
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Pustijanac E, Buršić M, Millotti G, Paliaga P, Iveša N, Cvek M. Tick-Borne Bacterial Diseases in Europe: Threats to public health. Eur J Clin Microbiol Infect Dis 2024:10.1007/s10096-024-04836-5. [PMID: 38676855 DOI: 10.1007/s10096-024-04836-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 04/22/2024] [Indexed: 04/29/2024]
Abstract
BACKGROUND Tick-borne diseases, caused by bacterial pathogens, pose a growing threat to public health in Europe. This paper provides an overview of the historical context of the discovery of the most impactful pathogens transmitted by ticks, including Borrelia burgdorferi sensu lato, Rickettsia spp., Anaplasma spp., Francisella spp., Ehrlichia spp., and Neoehrlichia mikurensis. Understanding the historical context of their discovery provides insight into the evolution of our understanding of these pathogens. METHODS AND RESULTS Systematic investigation of the prevalence and transmission dynamics of these bacterial pathogens is provided, highlighting the intricate relationships among ticks, host organisms, and the environment. Epidemiology is explored, providing an in-depth analysis of clinical features associated with infections. Diagnostic methodologies undergo critical examination, with a spotlight on technological advancements that enhance detection capabilities. Additionally, the paper discusses available treatment options, addressing existing therapeutic strategies and considering future aspects. CONCLUSIONS By integrating various pieces of information on these bacterial species, the paper aims to provide a comprehensive resource for researchers and healthcare professionals addressing the impact of bacterial tick-borne diseases in Europe. This review underscores the importance of understanding the complex details influencing bacterial prevalence and transmission dynamics to better combat these emerging public health threats.
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Affiliation(s)
- Emina Pustijanac
- Faculty of Natural Sciences, Juraj Dobrila University of Pula, Zagrebačka 30, 52100, Pula, Croatia.
| | - Moira Buršić
- Faculty of Natural Sciences, Juraj Dobrila University of Pula, Zagrebačka 30, 52100, Pula, Croatia
| | - Gioconda Millotti
- Faculty of Natural Sciences, Juraj Dobrila University of Pula, Zagrebačka 30, 52100, Pula, Croatia
| | - Paolo Paliaga
- Faculty of Natural Sciences, Juraj Dobrila University of Pula, Zagrebačka 30, 52100, Pula, Croatia
| | - Neven Iveša
- Faculty of Natural Sciences, Juraj Dobrila University of Pula, Zagrebačka 30, 52100, Pula, Croatia
| | - Maja Cvek
- Faculty of Medicine, University of Rijeka, Braće Branchetta 20, 51000, Rijeka, Croatia
- Teaching Institute of Public Health of the Region of Istria, Nazorova 23, 52100, Pula, Croatia
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3
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Haggerty K, Cantlay S, Young E, Cashbaugh MK, Delatore Iii EF, Schreiber R, Hess H, Komlosi DR, Butler S, Bolon D, Evangelista T, Hager T, Kelly C, Phillips K, Voellinger J, Shanks RMQ, Horzempa J. Identification of an N-terminal tag (580N) that improves the biosynthesis of fluorescent proteins in Francisella tularensis and other Gram-negative bacteria. Mol Cell Probes 2024; 74:101956. [PMID: 38492609 PMCID: PMC11000650 DOI: 10.1016/j.mcp.2024.101956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/12/2024] [Accepted: 03/13/2024] [Indexed: 03/18/2024]
Abstract
Utilization of fluorescent proteins is widespread for the study of microbial pathogenesis and host-pathogen interactions. Here, we discovered that linkage of the 36 N-terminal amino acids of FTL_0580 (a hypothetical protein of Francisella tularensis) to fluorescent proteins increases the fluorescence emission of bacteria that express these recombinant fusions. This N-terminal peptide will be referred to as 580N. Western blotting revealed that the linkage of 580N to Emerald Green Fluorescent Protein (EmGFP) in F. tularensis markedly improved detection of this protein. We therefore hypothesized that transcripts containing 580N may be translated more efficiently than those lacking the coding sequence for this leader peptide. In support, expression of emGFPFt that had been codon-optimized for F. tularensis, yielded significantly enhanced fluorescence than its non-optimized counterpart. Furthermore, fusing emGFP with coding sequence for a small N-terminal peptide (Serine-Lysine-Isoleucine-Lysine), which had previously been shown to inhibit ribosomal stalling, produced robust fluorescence when expressed in F. tularensis. These findings support the interpretation that 580N enhances the translation efficiency of fluorescent proteins in F. tularensis. Interestingly, expression of non-optimized 580N-emGFP produced greater fluorescence intensity than any other construct. Structural predictions suggested that RNA secondary structure also may be influencing translation efficiency. When expressed in Escherichia coli and Klebsiella pneumoniae bacteria, 580N-emGFP produced increased green fluorescence compared to untagged emGFP (neither allele was codon optimized for these bacteria). In conclusion, fusing the coding sequence for the 580N leader peptide to recombinant genes might serve as an economical alternative to codon optimization for enhancing protein expression in bacteria.
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Affiliation(s)
- Kristen Haggerty
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Stuart Cantlay
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Emily Young
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Mariah K Cashbaugh
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Elio F Delatore Iii
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Rori Schreiber
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Hayden Hess
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Daniel R Komlosi
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sarah Butler
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Dalton Bolon
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Theresa Evangelista
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Takoda Hager
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Claire Kelly
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Katherine Phillips
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Jada Voellinger
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA
| | - Robert M Q Shanks
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Joseph Horzempa
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV, USA.
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Wu Y, Gong X, Shen J, Zhu K. Postantibiotic leukocyte enhancement-mediated reduction of intracellular bacteria by macrophages. J Adv Res 2024; 58:117-128. [PMID: 37290606 PMCID: PMC10982861 DOI: 10.1016/j.jare.2023.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 05/22/2023] [Accepted: 05/28/2023] [Indexed: 06/10/2023] Open
Abstract
INTRODUCTION Potentiation of the bactericidal activities of leukocytes, including macrophages, upon antibacterial agent administration has been observed for several decades and is summarized as the postantibiotic leukocyte enhancement (PALE) theory. Antibiotics-induced bacterial sensitization to leukocytes is commonly recognized as the mechanism of PALE. However, the degree of sensitization drastically varies with antibiotic classes, and little is known about whether and how the potentiation of leukocytes contributes to PALE. OBJECTIVES In this study, we aim to develop a mechanistic understanding of PALE by investigating the immunoregulation of traditional antibiotics on macrophages. METHODS Interaction models between bacteria and macrophages were constructed to identify the effects of different antibiotics on the bactericidal activities of macrophages. Oxygen consumption rate, expression of oxidases, and antioxidants were then measured to evaluate the effects of fluoroquinolones (FQs) on the oxidative stress of macrophages. Furthermore, the modulation in endoplasmic reticulum stress and inflammation upon antibiotic treatment was detected to analyze the mechanisms. At last, the peritoneal infection model was utilized to verify the PALE in vivo. RESULTS Enrofloxacin significantly reduced the intracellular burden of diverse bacterial pathogens through promoting the accumulation of reactive oxygen species (ROS). The upregulated oxidative response accordingly reprograms the electron transport chain with decreased production of antioxidant enzymes to reduce internalized pathogens. Additionally, enrofloxacin modulated the expression and spatiotemporal localization of myeloperoxidase (MPO) to facilitate ROS accumulation to target invaded bacteria and downregulated inflammatory response to alleviate cellular injury. CONCLUSION Our findings demonstrate the crucial role of leukocytes in PALE, shedding light on the development of new host-directed antibacterial therapies and the design of rational dosage regimens.
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Affiliation(s)
- Yifan Wu
- National Key Laboratory of Veterinary Public Health Security, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Xiaoxia Gong
- National Key Laboratory of Veterinary Public Health Security, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Jianzhong Shen
- National Key Laboratory of Veterinary Public Health Security, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Kui Zhu
- National Key Laboratory of Veterinary Public Health Security, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
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Herron ICT, Laws TR, Nelson M. Marmosets as models of infectious diseases. Front Cell Infect Microbiol 2024; 14:1340017. [PMID: 38465237 PMCID: PMC10921895 DOI: 10.3389/fcimb.2024.1340017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 01/29/2024] [Indexed: 03/12/2024] Open
Abstract
Animal models of infectious disease often serve a crucial purpose in obtaining licensure of therapeutics and medical countermeasures, particularly in situations where human trials are not feasible, i.e., for those diseases that occur infrequently in the human population. The common marmoset (Callithrix jacchus), a Neotropical new-world (platyrrhines) non-human primate, has gained increasing attention as an animal model for a number of diseases given its small size, availability and evolutionary proximity to humans. This review aims to (i) discuss the pros and cons of the common marmoset as an animal model by providing a brief snapshot of how marmosets are currently utilized in biomedical research, (ii) summarize and evaluate relevant aspects of the marmoset immune system to the study of infectious diseases, (iii) provide a historical backdrop, outlining the significance of infectious diseases and the importance of developing reliable animal models to test novel therapeutics, and (iv) provide a summary of infectious diseases for which a marmoset model exists, followed by an in-depth discussion of the marmoset models of two studied bacterial infectious diseases (tularemia and melioidosis) and one viral infectious disease (viral hepatitis C).
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Affiliation(s)
- Ian C. T. Herron
- CBR Division, Defence Science and Technology Laboratory (Dstl), Salisbury, United Kingdom
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Degabriel M, Valeva S, Boisset S, Henry T. Pathogenicity and virulence of Francisella tularensis. Virulence 2023; 14:2274638. [PMID: 37941380 PMCID: PMC10653695 DOI: 10.1080/21505594.2023.2274638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 10/18/2023] [Indexed: 11/10/2023] Open
Abstract
Tularaemia is a zoonotic disease caused by the Gram-negative bacterium, Francisella tularensis. Depending on its entry route into the organism, F. tularensis causes different diseases, ranging from life-threatening pneumonia to less severe ulceroglandular tularaemia. Various strains with different geographical distributions exhibit different levels of virulence. F. tularensis is an intracellular bacterium that replicates primarily in the cytosol of the phagocytes. The main virulence attribute of F. tularensis is the type 6 secretion system (T6SS) and its effectors that promote escape from the phagosome. In addition, F. tularensis has evolved a peculiar envelope that allows it to escape detection by the immune system. In this review, we cover tularaemia, different Francisella strains, and their pathogenicity. We particularly emphasize the intracellular life cycle, associated virulence factors, and metabolic adaptations. Finally, we present how F. tularensis largely escapes immune detection to be one of the most infectious and lethal bacterial pathogens.
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Affiliation(s)
- Manon Degabriel
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
| | - Stanimira Valeva
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
| | - Sandrine Boisset
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
- Univ. Grenoble Alpes, CHU Grenoble Alpes, CNRS, CEA, UMR5075, Institut de Biologie Structurale, Grenoble, France
| | - Thomas Henry
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
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7
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Lin Q, Wang T, Zuo X, Ni H, Zhong J, Zhan L, Cheng H, Huang Y, Ding X, Yu H, Nie H. Anti-CD1d treatment suppresses immunogenic maturation of lung dendritic cells dependent on lung invariant natural killer T cells in asthmatic mice. Int Immunopharmacol 2023; 124:110921. [PMID: 37725846 DOI: 10.1016/j.intimp.2023.110921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 09/04/2023] [Accepted: 09/07/2023] [Indexed: 09/21/2023]
Abstract
Our previous findings show that invariant natural killer T (iNKT)cells can promote immunogenic maturation of lung dendritic cells (LDCs) to enhance Th2 cell responses in asthma. It has been accepted that recognition of glycolipid antigens presented by CD1d molecules by the T cell receptors of iNKT cells leads to iNKT cell activation. Therefore, we examine the immunoregulatory influences of anti-CD1d treatment on Th2 cell response and immunogenic maturation of LDCs and subsequently explored whether these influences were dependent on lung iNKT cells in asthmatic mice. We discoveredthat in wild-type mice sensitized and challenged with house dust mite or ovalbumin (OVA), anti-CD1d treatment inhibited Th2 cell response and immunogenic maturation of LDCs. LDCs from asthmatic mice with anti-CD1d treatment had a markedly decreased influence on Th2 cell responses in vivo and in vitro. Furthermore, anti-CD1d treatment reduced the abundance and activation of lung iNKT cells in asthmatic mice. Moreover, in asthmatic iNKT cell-deficient Jα18-/- mice, anti-CD1d treatment did not influence Th2 cell responses and immunogenic maturation of LDCs. Meanwhile, the quantity of CD40L+ iNKT cells in asthmatic mice was significant decreased by anti-CD1d treatment. Finally, the inhibition of anti-CD1d treatment on LDC immunogenic maturation and Th2 cell responses in asthmatic mice was reversed by anti-CD40 treatment. Our data suggest that anti-CD1d treatment can suppress Th2 cell responses through inhibiting immunogenic maturation of LDCs dependent on lung iNKT cells, which couldbe partially related to the downregulation of CD40L expression on lung iNKT cells in asthmatic mice.
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Affiliation(s)
- Qibin Lin
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Tong Wang
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Xiaoshu Zuo
- Department of Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Haiyang Ni
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Jieying Zhong
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Liying Zhan
- Department of Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Hong Cheng
- Department of Parmacy, Zhongnan Hospital of Wuhan University, Wuhan 430071, Hubei, China
| | - Yi Huang
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Xuhong Ding
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Hongying Yu
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China
| | - Hanxiang Nie
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan 430060, Hubei, China.
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Jessop F, Schwarz B, Bohrnsen E, Bosio CM. Route of Francisella tularensis infection informs spatiotemporal metabolic reprogramming and inflammation in mice. PLoS One 2023; 18:e0293450. [PMID: 37883420 PMCID: PMC10602361 DOI: 10.1371/journal.pone.0293450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023] Open
Abstract
Route of exposure to pathogens can inform divergent disease pathogenesis and mortality rates. However, the features that contribute to these differences are not well established. Host metabolism has emerged as a critical element governing susceptibility and the metabolism of tissue exposure sites are unique. Therefore, specific metabolic niches may contribute to the course and outcome of infection depending on route of infection. In the current study, we utilized a combination of imaging and systems metabolomics to map the spatiotemporal dynamics of the host response to intranasal (i.n.) or intradermal (i.d.) infection of mice using the bacterium Francisella tularensis subsp tularensis (FTT). FTT causes lethal disease through these infection routes with similar inoculation doses and replication kinetics, which allowed for isolation of host outcomes independent of bacterial burden. We observed metabolic modifications that were both route dependent and independent. Specifically, i.d. infection resulted in early metabolic reprogramming at the site of infection and draining lymph nodes, whereas the lungs and associated draining lymph nodes were refractory to metabolic reprogramming following i.n. infection. Irrespective of exposure route, FTT promoted metabolic changes in systemic organs prior to colonization, and caused massive dysregulation of host metabolism in these tissues prior to onset of morbidity. Preconditioning infection sites towards a more glycolytic and pro-inflammatory state prior to infection exacerbated FTT replication within the lungs but not intradermal tissue. This enhancement of replication in the lungs was associated with the ability of FTT to limit redox imbalance and alter the pentose phosphate pathway. Together, these studies identify central metabolic features of the lung and dermal compartments that contribute to disease progression and identify potential tissue specific targets that may be exploited for novel therapeutic approaches.
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Affiliation(s)
- Forrest Jessop
- Rocky Mountain Laboratories, NIAID, Hamilton, MT, United States of America
| | - Benjamin Schwarz
- Rocky Mountain Laboratories, NIAID, Hamilton, MT, United States of America
| | - Eric Bohrnsen
- Rocky Mountain Laboratories, NIAID, Hamilton, MT, United States of America
| | - Catharine M. Bosio
- Rocky Mountain Laboratories, NIAID, Hamilton, MT, United States of America
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Zhang M, Lan H, Peng S, Zhou W, Wang X, Jiang M, Hong J, Zhang Q. MiR-223-3p attenuates radiation-induced inflammatory response and inhibits the activation of NLRP3 inflammasome in macrophages. Int Immunopharmacol 2023; 122:110616. [PMID: 37459784 DOI: 10.1016/j.intimp.2023.110616] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 06/29/2023] [Accepted: 07/04/2023] [Indexed: 08/25/2023]
Abstract
Macrophage pyroptosis plays an important role in the development of radiation-induced cell and tissue damage, leading to acute lung injury. However, the underlying mechanisms of NOD-like receptor thermal protein domain-associated protein 3 (NLRP3)-mediated macrophage pyroptosis and the regulatory factors involved in radiation-induced pyroptosis are unclear. In this study, the expression of the NLRP3 inflammasome and pyroptosis-associated factors in murine macrophage cell lines was investigated after ionizing radiation. High-throughput RNA sequencing was performed to identify and characterize miRNAs and mRNA transcripts associated with NLRP3-mediated cell death. Our results demonstrated that cleaved-caspase-1 (p10) and N-terminal domain of gasdermin-D (GSDMD-N) were upregulated, and the number of NLRP3 inflammasomes and pyroptotic cells increased in murine macrophage cell lines after irradiation (8 Gy). Comparativeprofiling of 300miRNAs revealed that 41 miRNAsexhibited significantly different expression after 8 Gy of irradiation. Granulocyte-specific microRNA-223-3p (miR-223-3p) is a negative regulator of NLRP3. In vitro experiments revealed that the expression of miR-223-3p was significantly altered by irradiation. Moreover, miR-223-3p decreased the expression of NLRP3 and proinflammatory factors, resulting in reduced pyroptosis in irradiated murine macrophages. Subsequently, in vivo experiments revealed the efficacy of miR-223-3p supplementation in ameliorating alveolar macrophage (AM) pyroptosis, attenuating the infiltration of inflammatory monocytes, and significantly alleviating the severity of acute radiation-induced lung injury (ARILI). Our findings suggest that the miR-223-3p/NLRP3/caspase-1 axis is involved in radiation-induced AM pyroptosis and ARILI.
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Affiliation(s)
- Mingwei Zhang
- Department of Oncology, Fujian Medical University Union Hospital, Fuzhou, China; Department of Radiotherapy, Cancer Center, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China; Department of Radiotherapy, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital of Fujian Medical University, Fuzhou, China; Key Laboratory of Radiation Biology of Fujian Higher Education Institutions, The First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Hailin Lan
- Department of Radiotherapy, Cancer Center, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China; Department of Radiotherapy, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital of Fujian Medical University, Fuzhou, China; Key Laboratory of Radiation Biology of Fujian Higher Education Institutions, The First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Shaoli Peng
- Department of Radiotherapy, Cancer Center, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Weitong Zhou
- Department of Radiotherapy, Cancer Center, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Xuezhen Wang
- Department of Radiotherapy, Cancer Center, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Meina Jiang
- Department of Radiotherapy, Cancer Center, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Jinsheng Hong
- Department of Radiotherapy, Cancer Center, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China; Department of Radiotherapy, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital of Fujian Medical University, Fuzhou, China; Key Laboratory of Radiation Biology of Fujian Higher Education Institutions, The First Affiliated Hospital, Fujian Medical University, Fuzhou, China.
| | - Qiuyu Zhang
- Institute of Immunotherapy, Fujian Medical University, Fuzhou, China.
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Benziger PT, Kopping EJ, McLaughlin PA, Thanassi DG. Francisella tularensis disrupts TLR2-MYD88-p38 signaling early during infection to delay apoptosis of macrophages and promote virulence in the host. mBio 2023; 14:e0113623. [PMID: 37404047 PMCID: PMC10470500 DOI: 10.1128/mbio.01136-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 05/24/2023] [Indexed: 07/06/2023] Open
Abstract
Francisella tularensis is a zoonotic pathogen and the causative agent of tularemia. F. tularensis replicates to high levels within the cytosol of macrophages and other host cells while subverting the host response to infection. Critical to the success of F. tularensis is its ability to delay macrophage apoptosis to maintain its intracellular replicative niche. However, the host-signaling pathway(s) modulated by F. tularensis to delay apoptosis are poorly characterized. The outer membrane channel protein TolC is required for F. tularensis virulence and its ability to suppress apoptosis and cytokine expression during infection of macrophages. We took advantage of the F. tularensis ∆tolC mutant phenotype to identify host pathways that are important for activating macrophage apoptosis and that are disrupted by the bacteria. Comparison of macrophages infected with wild-type or ∆tolC F. tularensis revealed that the bacteria interfere with TLR2-MYD88-p38 signaling at early times post infection to delay apoptosis, dampen innate host responses, and preserve the intracellular replicative niche. Experiments using the mouse pneumonic tularemia model confirmed the in vivo relevance of these findings, revealing contributions of TLR2 and MYD88 signaling to the protective host response to F. tularensis, which is modulated by the bacteria to promote virulence. IMPORTANCE Francisella tularensis is a Gram-negative intracellular bacterial pathogen and the causative agent of the zoonotic disease tularemia. F. tularensis, like other intracellular pathogens, modulates host-programmed cell death pathways to ensure its replication and survival. We previously identified the outer membrane channel protein TolC as required for the ability of F. tularensis to delay host cell death. However, the mechanism by which F. tularensis delays cell death pathways during intracellular replication is unclear despite being critical to pathogenesis. In the present study, we address this gap in knowledge by taking advantage of ∆tolC mutants of F. tularensis to uncover signaling pathways governing host apoptotic responses to F. tularensis and which are modulated by the bacteria during infection to promote virulence. These findings reveal mechanisms by which intracellular pathogens subvert host responses and enhance our understanding of the pathogenesis of tularemia.
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Affiliation(s)
- P. Todd Benziger
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
- Center for Infectious Diseases, Stony Brook University, Stony Brook, New York, USA
| | - Erik J. Kopping
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
- Center for Infectious Diseases, Stony Brook University, Stony Brook, New York, USA
| | - Patrick A. McLaughlin
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
- Center for Infectious Diseases, Stony Brook University, Stony Brook, New York, USA
| | - David G. Thanassi
- Department of Microbiology and Immunology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
- Center for Infectious Diseases, Stony Brook University, Stony Brook, New York, USA
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11
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Wang Y, Ledvina HE, Tower CA, Kambarev S, Liu E, Charity JC, Kreuk LSM, Tang Q, Chen Q, Gallagher LA, Radey MC, Rerolle GF, Li Y, Penewit KM, Turkarslan S, Skerrett SJ, Salipante SJ, Baliga NS, Woodward JJ, Dove SL, Peterson SB, Celli J, Mougous JD. Discovery of a glutathione utilization pathway in Francisella that shows functional divergence between environmental and pathogenic species. Cell Host Microbe 2023; 31:1359-1370.e7. [PMID: 37453420 PMCID: PMC10763578 DOI: 10.1016/j.chom.2023.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 05/19/2023] [Accepted: 06/20/2023] [Indexed: 07/18/2023]
Abstract
Glutathione (GSH) is an abundant metabolite within eukaryotic cells that can act as a signal, a nutrient source, or serve in a redox capacity for intracellular bacterial pathogens. For Francisella, GSH is thought to be a critical in vivo source of cysteine; however, the cellular pathways permitting GSH utilization by Francisella differ between strains and have remained poorly understood. Using genetic screening, we discovered a unique pathway for GSH utilization in Francisella. Whereas prior work suggested GSH catabolism initiates in the periplasm, the pathway we define consists of a major facilitator superfamily (MFS) member that transports intact GSH and a previously unrecognized bacterial cytoplasmic enzyme that catalyzes the first step of GSH degradation. Interestingly, we find that the transporter gene for this pathway is pseudogenized in pathogenic Francisella, explaining phenotypic discrepancies in GSH utilization among Francisella spp. and revealing a critical role for GSH in the environmental niche of these bacteria.
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Affiliation(s)
- Yaxi Wang
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Hannah E Ledvina
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Catherine A Tower
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Stanimir Kambarev
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA 99164, USA
| | - Elizabeth Liu
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - James C Charity
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | - Qing Tang
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Qiwen Chen
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Larry A Gallagher
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Matthew C Radey
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Guilhem F Rerolle
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Yaqiao Li
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA; Institute for Systems Biology, Seattle, WA 98109, USA
| | - Kelsi M Penewit
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | | | - Shawn J Skerrett
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Stephen J Salipante
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | | | - Joshua J Woodward
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Simon L Dove
- Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - S Brook Peterson
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA
| | - Jean Celli
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA 99164, USA
| | - Joseph D Mougous
- Department of Microbiology, University of Washington, Seattle, WA 98109, USA; Microbial Interactions and Microbiome Center, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98109, USA.
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12
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Köppen K, Fatykhova D, Holland G, Rauch J, Tappe D, Graff M, Rydzewski K, Hocke AC, Hippenstiel S, Heuner K. Ex vivo infection model for Francisella using human lung tissue. Front Cell Infect Microbiol 2023; 13:1224356. [PMID: 37492528 PMCID: PMC10365108 DOI: 10.3389/fcimb.2023.1224356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 06/23/2023] [Indexed: 07/27/2023] Open
Abstract
Introduction Tularemia is mainly caused by Francisella tularensis (Ft) subsp. tularensis (Ftt) and Ft subsp. holarctica (Ftt) in humans and in more than 200 animal species including rabbits and hares. Human clinical manifestations depend on the route of infection and range from flu-like symptoms to severe pneumonia with a mortality rate up to 60% without treatment. So far, only 2D cell culture and animal models are used to study Francisella virulence, but the gained results are transferable to human infections only to a certain extent. Method In this study, we firstly established an ex vivo human lung tissue infection model using different Francisella strains: Ftt Life Vaccine Strain (LVS), Ftt LVS ΔiglC, Ftt human clinical isolate A-660 and a German environmental Francisella species strain W12-1067 (F-W12). Human lung tissue was used to determine the colony forming units and to detect infected cell types by using spectral immunofluorescence and electron microscopy. Chemokine and cytokine levels were measured in culture supernatants. Results Only LVS and A-660 were able to grow within the human lung explants, whereas LVS ΔiglC and F-W12 did not replicate. Using human lung tissue, we observed a greater increase of bacterial load per explant for patient isolate A-660 compared to LVS, whereas a similar replication of both strains was observed in cell culture models with human macrophages. Alveolar macrophages were mainly infected in human lung tissue, but Ftt was also sporadically detected within white blood cells. Although Ftt replicated within lung tissue, an overall low induction of pro-inflammatory cytokines and chemokines was observed. A-660-infected lung explants secreted slightly less of IL-1β, MCP-1, IP-10 and IL-6 compared to Ftt LVS-infected explants, suggesting a more repressed immune response for patient isolate A-660. When LVS and A-660 were used for simultaneous co-infections, only the ex vivo model reflected the less virulent phenotype of LVS, as it was outcompeted by A-660. Conclusion We successfully implemented an ex vivo infection model using human lung tissue for Francisella. The model delivers considerable advantages and is able to discriminate virulent Francisella from less- or non-virulent strains and can be used to investigate the role of specific virulence factors.
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Affiliation(s)
- Kristin Köppen
- Working group “Cellular Interactions of Bacterial Pathogens”, Centre for Biological Threats and Special Pathogens, Highly Pathogenic Microorganisms (ZBS 2), Robert Koch Institute, Berlin, Germany
| | - Diana Fatykhova
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Gudrun Holland
- Advanced Light and Electron Microscopy, ZBS 4, Robert Koch Institute, Berlin, Germany
| | - Jessica Rauch
- Research Group Zoonoses, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Dennis Tappe
- Research Group Zoonoses, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Mareike Graff
- Department for General and Thoracic Surgery, DRK Clinics, Berlin, Germany
| | - Kerstin Rydzewski
- Working group “Cellular Interactions of Bacterial Pathogens”, Centre for Biological Threats and Special Pathogens, Highly Pathogenic Microorganisms (ZBS 2), Robert Koch Institute, Berlin, Germany
| | - Andreas C. Hocke
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Stefan Hippenstiel
- Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Klaus Heuner
- Working group “Cellular Interactions of Bacterial Pathogens”, Centre for Biological Threats and Special Pathogens, Highly Pathogenic Microorganisms (ZBS 2), Robert Koch Institute, Berlin, Germany
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13
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Alqahtani M, Ma Z, Miller J, Yu J, Malik M, Bakshi CS. Comparative analysis of absent in melanoma 2-inflammasome activation in Francisella tularensis and Francisella novicida. Front Microbiol 2023; 14:1188112. [PMID: 37266012 PMCID: PMC10230036 DOI: 10.3389/fmicb.2023.1188112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/02/2023] [Indexed: 06/03/2023] Open
Abstract
Francisella tularensis is a highly virulent Gram-negative bacterium that causes the fatal zoonotic disease tularemia. The mechanisms and signaling pathways leading to the absent in melanoma 2 (Aim2) inflammasome activation have been elegantly elucidated using Francisella novicida as a model. Although not pathogenic for humans, F. novicida can cause tularemia in mice, and the inflammatory response it triggers is the polar opposite to that observed in mice infected with F. tularensis strains. This study aimed to understand the mechanisms of Aim2 inflammasome activation in F. tularensis-infected macrophages. The results reveal that macrophages infected with the F. tularensis live vaccine strain (LVS) induce lower levels of Aim2-dependent IL-1β than those infected with F. novicida. The suppression/weak activation of Aim2 in F. tularensis LVS-infected macrophages is due to the suppression of the cGAS-STING DNA-sensing pathway. Furthermore, the introduction of exogenous F. tularensis LVS DNA into the cytosol of the F. tularensis LVS-infected macrophages, alone or in conjunction with a priming signal, failed to restore IL-1β levels similar to those observed for F. novicida-infected macrophages. These results indicated that, in addition to the bacterial DNA, DNA from some other sources, specifically from the damaged mitochondria, might contribute to the robust Aim2-dependent IL-1β levels observed in F. novicida-infected macrophages. The results indicate that F. tularensis LVS induces mitophagy that may potentially prevent the leakage of mitochondrial DNA and the subsequent activation of the Aim2 inflammasome. Collectively, this study demonstrates that the mechanisms of Aim2 inflammasome activation established for F. novicida are not operative in F. tularensis.
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Affiliation(s)
- Maha Alqahtani
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Zhuo Ma
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
| | - Jacob Miller
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
| | - Jen Yu
- Electron Microscopy Laboratory, Department of Pathology, Westchester Medical Center, Valhalla, NY, United States
| | - Meenakshi Malik
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
| | - Chandra Shekhar Bakshi
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
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14
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Dow J, Cytlak UM, Casulli J, McEntee CP, Smedley C, Hodge SH, D’Elia RV, Hepworth MR, Travis MA. Group 2 Innate Lymphoid Cells Are Detrimental to the Control of Infection with Francisella tularensis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 210:618-627. [PMID: 36602520 PMCID: PMC9946898 DOI: 10.4049/jimmunol.2100651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 12/02/2022] [Indexed: 01/06/2023]
Abstract
Innate lymphoid cells (ILCs) are capable of rapid response to a wide variety of immune challenges, including various respiratory pathogens. Despite this, their role in the immune response against the lethal intracellular bacterium Francisella tularensis is not yet known. In this study, we demonstrate that infection of the airways with F. tularensis results in a significant reduction in lung type 2 ILCs (ILC2s) in mice. Conversely, the expansion of ILC2s via treatment with the cytokine IL-33, or by adoptive transfer of ILC2s, resulted in significantly enhanced bacterial burdens in the lung, liver, and spleen, suggesting that ILC2s may favor severe infection. Indeed, specific reduction of ILC2s in a transgenic mouse model results in a reduction in lung bacterial burden. Using an in vitro culture system, we show that IFN-γ from the live vaccine strain-infected lung reduces ILC2 numbers, suggesting that this cytokine in the lung environment is mechanistically important in reducing ILC2 numbers during infection. Finally, we show Ab-mediated blockade of IL-5, of which ILC2s are a major innate source, reduces bacterial burden postinfection, suggesting that IL-5 production by ILC2s may play a role in limiting protective immunity. Thus, overall, we highlight a negative role for ILC2s in the control of infection with F. tularensis. Our work therefore highlights the role of ILC2s in determining the severity of potentially fatal airway infections and raises the possibility of interventions targeting innate immunity during infection with F. tularensis to benefit the host.
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Affiliation(s)
- Joshua Dow
- Lydia Becker Institute for Immunology and Inflammation, Manchester, United Kingdom
- Wellcome Trust Centre for Cell-Matrix Research, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, United Kingdom
| | - Urszula M. Cytlak
- Lydia Becker Institute for Immunology and Inflammation, Manchester, United Kingdom
- Wellcome Trust Centre for Cell-Matrix Research, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, United Kingdom
- Targeted Therapy Group, Division of Cancer Sciences, Manchester, United Kingdom
| | - Joshua Casulli
- Lydia Becker Institute for Immunology and Inflammation, Manchester, United Kingdom
- Wellcome Trust Centre for Cell-Matrix Research, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, United Kingdom
| | - Craig P. McEntee
- Lydia Becker Institute for Immunology and Inflammation, Manchester, United Kingdom
- Wellcome Trust Centre for Cell-Matrix Research, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, United Kingdom
| | - Catherine Smedley
- Lydia Becker Institute for Immunology and Inflammation, Manchester, United Kingdom
- Wellcome Trust Centre for Cell-Matrix Research, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, United Kingdom
| | - Suzanne H. Hodge
- Lydia Becker Institute for Immunology and Inflammation, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, United Kingdom
| | - Riccardo V. D’Elia
- Defence Science and Technology Laboratory, Porton Down, Salisbury, United Kingdom; and
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom
| | - Matthew R. Hepworth
- Lydia Becker Institute for Immunology and Inflammation, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, United Kingdom
| | - Mark A. Travis
- Lydia Becker Institute for Immunology and Inflammation, Manchester, United Kingdom
- Wellcome Trust Centre for Cell-Matrix Research, Manchester, United Kingdom
- Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, United Kingdom
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15
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Valeva SV, Degabriel M, Michal F, Gay G, Rohde JR, Randow F, Lagrange B, Henry T. Comparative study of GBP recruitment on two cytosol-dwelling pathogens, Francisella novicida and Shigella flexneri highlights differences in GBP repertoire and in GBP1 motif requirements. Pathog Dis 2023; 81:ftad005. [PMID: 37012222 DOI: 10.1093/femspd/ftad005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 03/31/2023] [Indexed: 04/05/2023] Open
Abstract
Guanylate-Binding Proteins are interferon-inducible GTPases that play a key role in cell autonomous responses against intracellular pathogens. Despite sharing high sequence similarity, subtle differences among GBPs translate into functional divergences that are still largely not understood. A key GBP feature is the formation of supramolecular GBP complexes on the bacterial surface. Such complexes are observed when GBP1 binds lipopolysaccharide (LPS) from Shigella and Salmonella and further recruits GBP2-4. Here, we compared GBP recruitment on two cytosol-dwelling pathogens, Francisella novicida and S. flexneri. Francisella novicida was coated by GBP1 and GBP2 and to a lower extent by GBP4 in human macrophages. Contrary to S. flexneri, F. novicida was not targeted by GBP3, a feature independent of T6SS effectors. Multiple GBP1 features were required to promote targeting to F. novicida while GBP1 targeting to S. flexneri was much more permissive to GBP1 mutagenesis suggesting that GBP1 has multiple domains that cooperate to recognize F. novicida atypical LPS. Altogether our results indicate that the repertoire of GBPs recruited onto specific bacteria is dictated by GBP-specific features and by specific bacterial factors that remain to be identified.
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Affiliation(s)
- Stanimira V Valeva
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
| | - Manon Degabriel
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
| | - Fanny Michal
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
| | - Gabrielle Gay
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
| | - John R Rohde
- Department of Microbiology and Immunology, Dalhousie University, Halifax, B3H 4R2, NS, Canada
| | - Felix Randow
- Division of Protein and Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, CB2 0QH, Cambridge, United Kingdom
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, CB2 0QH, Cambridge, United Kingdom
| | - Brice Lagrange
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
| | - Thomas Henry
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, F-69007, Lyon, France
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16
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Schwarz B, Roberts LM, Bohrnsen E, Jessop F, Wehrly TD, Shaia C, Bosio CM. Contribution of Lipid Mediators in Divergent Outcomes following Acute Bacterial and Viral Lung Infections in the Obese Host. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 209:1323-1334. [PMID: 36002235 PMCID: PMC9529825 DOI: 10.4049/jimmunol.2200162] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 08/02/2022] [Indexed: 01/04/2023]
Abstract
Obesity is considered an important comorbidity for a range of noninfectious and infectious disease states including those that originate in the lung, yet the mechanisms that contribute to this susceptibility are not well defined. In this study, we used the diet-induced obesity (DIO) mouse model and two models of acute pulmonary infection, Francisella tularensis subspecies tularensis strain SchuS4 and SARS-CoV-2, to uncover the contribution of obesity in bacterial and viral disease. Whereas DIO mice were more resistant to infection with SchuS4, DIO animals were more susceptible to SARS-CoV-2 infection compared with regular weight mice. In both models, neither survival nor morbidity correlated with differences in pathogen load, overall cellularity, or influx of inflammatory cells in target organs of DIO and regular weight animals. Increased susceptibility was also not associated with exacerbated production of cytokines and chemokines in either model. Rather, we observed pathogen-specific dysregulation of the host lipidome that was associated with vulnerability to infection. Inhibition of specific pathways required for generation of lipid mediators reversed resistance to both bacterial and viral infection. Taken together, our data demonstrate disparity among obese individuals for control of lethal bacterial and viral infection and suggest that dysregulation of the host lipidome contributes to increased susceptibility to viral infection in the obese host.
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Affiliation(s)
- Benjamin Schwarz
- Immunity to Pulmonary Pathogens Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT; and
| | - Lydia M Roberts
- Immunity to Pulmonary Pathogens Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT; and
| | - Eric Bohrnsen
- Immunity to Pulmonary Pathogens Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT; and
| | - Forrest Jessop
- Immunity to Pulmonary Pathogens Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT; and
| | - Tara D Wehrly
- Immunity to Pulmonary Pathogens Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT; and
| | - Carl Shaia
- Rocky Mountain Veterinary Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT
| | - Catharine M Bosio
- Immunity to Pulmonary Pathogens Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT; and
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17
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Cantlay S, Kaftanic C, Horzempa J. PdpC, a secreted effector protein of the type six secretion system, is required for erythrocyte invasion by Francisella tularensis LVS. Front Cell Infect Microbiol 2022; 12:979693. [PMID: 36237421 PMCID: PMC9552824 DOI: 10.3389/fcimb.2022.979693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 09/02/2022] [Indexed: 12/01/2022] Open
Abstract
Francisella tularensis is a gram negative, intracellular pathogen that is the causative agent of the potentially fatal disease, tularemia. During infection, F. tularensis is engulfed by and replicates within host macrophages. Additionally, this bacterium has also been shown to invade human erythrocytes and, in both cases, the Type Six Secretion System (T6SS) is required for these host-pathogen interaction. One T6SS effector protein, PdpC, is important for macrophage infection, playing a role in phagolysosomal escape and intracellular replication. To determine if PdpC also plays a role in erythrocyte invasion, we constructed a pdpC-null mutant in the live vaccine strain, F. tularensis LVS. We show that PdpC is required for invasion of human and sheep erythrocytes during in vitro assays and that reintroduction of a copy of pdpC, in trans, rescues this phenotype. The interaction with human erythrocytes was further characterized using double-immunofluorescence microscopy to show that PdpC is required for attachment of F. tularensis LVS to erythrocytes as well as invasion. To learn more about the role of PdpC in erythrocyte invasion we generated a strain of F. tularensis LVS expressing pdpC-emgfp. PdpC-EmGFP localizes as discrete foci in a subset of F. tularensis LVS cells grown in broth culture and accumulates in erythrocytes during invasion assays. Our results are the first example of a secreted effector protein of the T6SS shown to be involved in erythrocyte invasion and indicate that PdpC is secreted into erythrocytes during invasion.
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Affiliation(s)
| | | | - Joseph Horzempa
- Department of Biological Sciences, West Liberty University, West Liberty, WV, United States
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18
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Krysa SJ, Allen LAH. Metabolic Reprogramming Mediates Delayed Apoptosis of Human Neutrophils Infected With Francisella tularensis. Front Immunol 2022; 13:836754. [PMID: 35693822 PMCID: PMC9174434 DOI: 10.3389/fimmu.2022.836754] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 04/28/2022] [Indexed: 01/15/2023] Open
Abstract
Neutrophils (polymorphonuclear leukocytes, PMNs) have a distinctively short lifespan, and tight regulation of cell survival and death is imperative for their normal function. We demonstrated previously that Francisella tularensis extends human neutrophil lifespan, which elicits an impaired immune response characterized by neutrophil dysfunction. Herein, we extended these studies, including our transcriptional profiling data, and employed Seahorse extracellular flux analysis, gas chromatography-mass spectrometry metabolite analysis, flow cytometry and several other biochemical approaches to demonstrate that the delayed apoptosis observed in F. tularensis-infected neutrophils is mediated, in part, by metabolic reprogramming. Specifically, we show that F. tularensis-infected neutrophils exhibited a unique metabolic signature characterized by increased glycolysis, glycolytic flux and glucose uptake, downregulation of the pentose phosphate pathway, and complex glycogen dynamics. Glucose uptake and glycolysis were essential for cell longevity, although glucose-6-phosphate translocation into the endoplasmic reticulum was not, and we identify depletion of glycogen as a potential trigger of apoptosis onset. In keeping with this, we also demonstrate that ablation of apoptosis with the pan-caspase inhibitor Q-VD-OPh was sufficient to profoundly increase glycolysis and glycogen stores in the absence of infection. Taken together, our data significantly advance understanding of neutrophil immunometabolism and its capacity to regulate cell lifespan.
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Affiliation(s)
- Samantha J. Krysa
- Inflammation Program, University of Iowa, Iowa City, IA, United States,Molecular Medicine Program, University of Iowa, Iowa City, IA, United States,Iowa City VA Health Care System, Iowa City, IA, United States
| | - Lee-Ann H. Allen
- Inflammation Program, University of Iowa, Iowa City, IA, United States,Molecular Medicine Program, University of Iowa, Iowa City, IA, United States,Iowa City VA Health Care System, Iowa City, IA, United States,Department of Medicine, Division of Infectious Diseases, University of Iowa, Iowa City, IA, United States,Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States,Harry S. Truman Memorial VA Hospital, Columbia, MO, United States,Department of Molecular Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MO, United States,*Correspondence: Lee-Ann H. Allen,
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Ma Z, Higgs M, Alqahtani M, Bakshi CS, Malik M. ThioredoxinA1 Controls the Oxidative Stress Response of Francisella tularensis Live Vaccine Strain (LVS). J Bacteriol 2022; 204:e0008222. [PMID: 35475633 PMCID: PMC9112935 DOI: 10.1128/jb.00082-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 04/01/2022] [Indexed: 11/20/2022] Open
Abstract
Francisella tularensis is an intracellular, Gram-negative bacterium known for causing a disease known as tularemia in the Northern Hemisphere. F. tularensis is classified as a category A select agent by the CDC based on its possible use as a bioterror agent. F. tularensis overcomes oxidative stress encountered during its growth in the environment or host macrophages by encoding antioxidant enzymes such as superoxide dismutases, catalase, and alkylhydroperoxy reductase. These antioxidant enzymes are regulated by the oxidative stress response regulator, OxyR. In addition to these antioxidant enzymes, F. tularensis also encodes two thioredoxins, TrxA1 (FTL_0611) and TrxA2 (FTL_1224); however, their role in the oxidative stress response of F. tularensis is not known. This study investigated the role of thioredoxins of F. tularensis in the oxidative stress response and intracellular survival. Our results demonstrate that TrxA1 but not TrxA2 plays a major role in the oxidative stress response of F. tularensis. Most importantly, this study elucidates a novel mechanism through which the TrxA1 of F. tularensis controls the oxidative stress response by regulating the expression of the master regulator, oxyR. Further, TrxA1 is required for the intramacrophage survival and growth of Francisella. Overall, this study describes a novel role of thioredoxin, TrxA1, in regulating the oxidative stress response of F. tularensis. IMPORTANCE The role of thioredoxins in the oxidative stress response of F. tularensis is not known. This study demonstrates that of the two thioredoxins, TrxA1 is vital to counter the oxidative stress in F. tularensis live vaccine strain (LVS). Furthermore, this study shows differences in the well-studied thioredoxins of Escherichia coli. First, the expression of TrxA1 of F. tularensis is independent of the oxidative stress response regulator, OxyR. Second and most importantly, TrxA1 regulates the expression of oxyR and, therefore, the OxyR-dependent oxidative stress response of F. tularensis. Overall, this study reports a novel regulatory role of TrxA1 of F. tularensis in the oxidative stress response.
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Affiliation(s)
- Zhuo Ma
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, New York, USA
| | - Matthew Higgs
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, New York, USA
| | - Maha Alqahtani
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
| | - Chandra Shekhar Bakshi
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
| | - Meenakshi Malik
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, New York, USA
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20
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Marghani D, Ma Z, Centone AJ, Huang W, Malik M, Bakshi CS. An AraC/XylS Family Transcriptional Regulator Modulates the Oxidative Stress Response of Francisella tularensis. J Bacteriol 2021; 203:e0018521. [PMID: 34543107 PMCID: PMC8570275 DOI: 10.1128/jb.00185-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/09/2021] [Indexed: 11/20/2022] Open
Abstract
Francisella tularensis is a Gram-negative bacterium that causes a fatal human disease known as tularemia. The Centers for Disease Control and Prevention have classified F. tularensis as a category A tier 1 select agent. The virulence mechanisms of Francisella are not entirely understood. Francisella possesses very few transcription regulators, and most of these regulate the expression of genes involved in intracellular survival and virulence. The F. tularensis genome sequence analysis reveals an AraC (FTL_0689) transcriptional regulator homologous to the AraC/XylS family of transcriptional regulators. In Gram-negative bacteria, AraC activates genes required for l-arabinose utilization and catabolism. The role of the FTL_0689 regulator in F. tularensis is not known. In this study, we characterized the role of FTL_0689 in the gene regulation of F. tularensis and investigated its contribution to intracellular survival and virulence. The results demonstrate that FTL_0689 in Francisella is not required for l-arabinose utilization. Instead, FTL_0689 specifically regulates the expression of the oxidative and global stress response, virulence, metabolism, and other key pathways genes required by Francisella when exposed to oxidative stress. The FTL_0689 mutant is attenuated for intramacrophage growth and virulence in mice. Based on the deletion mutant phenotype, FTL_0689 was termed osrR (oxidative stress response regulator). Altogether, this study elucidates the role of the osrR transcriptional regulator in tularemia pathogenesis. IMPORTANCE The virulence mechanisms of category A select agent Francisella tularensis, the causative agent of a fatal human disease known as tularemia, remain largely undefined. The present study investigated the role of a transcriptional regulator and its overall contribution to the oxidative stress resistance of F. tularensis. The results provide an insight into a novel gene regulatory mechanism, especially when Francisella is exposed to oxidative stress conditions. Understanding such Francisella- specific regulatory mechanisms will help identify potential targets for developing effective therapies and vaccines to prevent tularemia.
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Affiliation(s)
- Dina Marghani
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
| | - Zhuo Ma
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, New York, USA
| | - Anthony J. Centone
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
| | - Weihua Huang
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
| | - Meenakshi Malik
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, New York, USA
| | - Chandra Shekhar Bakshi
- Department of Pathology, Microbiology, and Immunology, New York Medical College, Valhalla, New York, USA
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21
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Suresh RV, Bradley EW, Higgs M, Russo VC, Alqahtani M, Huang W, Bakshi CS, Malik M. Nlrp3 Increases the Host's Susceptibility to Tularemia. Front Microbiol 2021; 12:725572. [PMID: 34690967 PMCID: PMC8527020 DOI: 10.3389/fmicb.2021.725572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/08/2021] [Indexed: 11/13/2022] Open
Abstract
Francisella tularensis (F. tularensis) is a Gram-negative, intracellular bacterium and the causative agent of a fatal human disease known as tularemia. The CDC has classified F. tularensis as a Tier 1 Category A select agent based on its ease of aerosolization, low infectious dose, past use as a bioweapon, and the potential to be used as a bioterror agent. Francisella has a unique replication cycle. Upon its uptake, Francisella remains in the phagosomes for a short period and then escapes into the cytosol, where the replication occurs. Francisella is recognized by cytosolic pattern recognition receptors, Absent In Melanoma 2 (Aim2) and Nacht LRR and PYD domains containing Protein 3 (Nlrp3). The recognition of Francisella ligands by Aim2 and Nlrp3 triggers the assembly and activation of the inflammasome. The mechanism of activation of Aim2 is well established; however, how Nlrp3 inflammasome is activated in response to F. tularensis infection is not known. Unlike Aim2, the protective role of Nlrp3 against Francisella infection is not fully established. This study investigated the role of Nlrp3 and the potential mechanisms through which Nlrp3 exerts its detrimental effects on the host in response to F. tularensis infection. The results from in vitro studies demonstrate that Nlrp3 dampens NF-κB and MAPK signaling, and pro-inflammatory cytokine production, which allows replication of F. tularensis in infected macrophages. In vivo, Nlrp3 deficiency results in differential expression of several genes required to induce a protective immune response against respiratory tularemia. Nlrp3-deficient mice mount a stronger innate immune response, clear bacteria efficiently with minimal organ damage, and are more resistant to Francisella infection than their wild-type counterparts. Together, these results demonstrate that Nlrp3 enhances the host's susceptibility to F. tularensis by modulating the protective innate immune responses. Collectively, this study advances our understanding of the detrimental role of Nlrp3 in tularemia pathogenesis.
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Affiliation(s)
- Ragavan V. Suresh
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Elizabeth W. Bradley
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
| | - Matthew Higgs
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
| | - Vincenzo C. Russo
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
| | - Maha Alqahtani
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Wiehua Huang
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Chandra Shekhar Bakshi
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Meenakshi Malik
- Department of Basic and Clinical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
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22
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Deletion Mutants of Francisella Phagosomal Transporters FptA and FptF Are Highly Attenuated for Virulence and Are Protective Against Lethal Intranasal Francisella LVS Challenge in a Murine Model of Respiratory Tularemia. Pathogens 2021; 10:pathogens10070799. [PMID: 34202420 PMCID: PMC8308642 DOI: 10.3390/pathogens10070799] [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: 05/11/2021] [Revised: 06/09/2021] [Accepted: 06/17/2021] [Indexed: 11/17/2022] Open
Abstract
Francisella tularensis (Ft) is a Gram-negative, facultative intracellular bacterium that is a Tier 1 Select Agent of concern for biodefense for which there is no licensed vaccine. A subfamily of 9 Francisella phagosomal transporter (fpt) genes belonging to the Major Facilitator Superfamily of transporters was identified as critical to pathogenesis and potential targets for attenuation and vaccine development. We evaluated the attenuation and protective capacity of LVS derivatives with deletions of the fptA and fptF genes in the C57BL/6J mouse model of respiratory tularemia. LVSΔfptA and LVSΔfptF were highly attenuated with LD50 values of >20 times that of LVS when administered intranasally and conferred 100% protection against lethal challenge. Immune responses to the fpt mutant strains in mouse lungs on day 6 post-infection were substantially modified compared to LVS and were associated with reduced organ burdens and reduced pathology. The immune responses to LVSΔfptA and LVSΔfptF were characterized by decreased levels of IL-10 and IL-1β in the BALF versus LVS, and increased numbers of B cells, αβ and γδ T cells, NK cells, and DCs versus LVS. These results support a fundamental requirement for FptA and FptF in the pathogenesis of Ft and the modulation of the host immune response.
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23
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Cunningham AL, Mann BJ, Qin A, Santiago AE, Grassel C, Lipsky M, Vogel SN, Barry EM. Characterization of Schu S4 aro mutants as live attenuated tularemia vaccine candidates. Virulence 2021; 11:283-294. [PMID: 32241221 PMCID: PMC7161688 DOI: 10.1080/21505594.2020.1746557] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
There is a need for development of an effective vaccine against Francisella tularensis, as this potential bioweapon has a high mortality rate and low infectious dose when delivered via the aerosol route. Moreover, this Tier 1 agent has a history of weaponization. We engineered targeted mutations in the Type A strain F. tularensis subspecies tularensis Schu S4 in aro genes encoding critical enzymes in aromatic amino acid biosynthesis. F. tularensis Schu S4ΔaroC, Schu S4ΔaroD, and Schu S4ΔaroCΔaroD mutant strains were attenuated for intracellular growth in vitro and for virulence in vivo and, conferred protection against pulmonary wild-type (WT) F. tularensis Schu S4 challenge in the C57BL/6 mouse model. F. tularensis Schu S4ΔaroD was identified as the most promising vaccine candidate, demonstrating protection against high-dose intranasal challenge; it protected against 1,000 CFU Schu S4, the highest level of protection tested to date. It also provided complete protection against challenge with 92 CFU of a F. tularensis subspecies holarctica strain (Type B). Mice responded to vaccination with Schu S4ΔaroD with systemic IgM and IgG2c, as well as the production of a functional T cell response as measured in the splenocyte-macrophage co-culture assay. This vaccine was further characterized for dissemination, histopathology, and cytokine/chemokine gene induction at defined time points following intranasal vaccination which confirmed its attenuation compared to WT Schu S4. Cytokine, chemokine, and antibody induction patterns compared to wild-type Schu S4 distinguish protective vs. pathogenic responses to F. tularensis and elucidate correlates of protection associated with vaccination against this agent.
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Affiliation(s)
| | - Barbara J Mann
- Department of Medicine, Division of Infectious Diseases and International Heath, University of Virginia, Charlottesville, VA, USA
| | - Aiping Qin
- Department of Medicine, Division of Infectious Diseases and International Heath, University of Virginia, Charlottesville, VA, USA
| | - Araceli E Santiago
- Department of Pediatrics, University of Virginia, Charlottesville, VA, USA
| | - Christen Grassel
- Center for Vaccine Development, University of Maryland Baltimore, Baltimore, MD, USA
| | - Michael Lipsky
- Department of Pathology, University of Maryland Baltimore, Baltimore, MD, USA
| | - Stefanie N Vogel
- Department of Microbiology and Immunology, University of Maryland Baltimore, Baltimore, MD, USA
| | - Eileen M Barry
- Center for Vaccine Development, University of Maryland Baltimore, Baltimore, MD, USA
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24
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Zellner B, Mengin-Lecreulx D, Tully B, Gunning WT, Booth R, Huntley JF. A Francisella tularensis L,D-carboxypeptidase plays important roles in cell morphology, envelope integrity, and virulence. Mol Microbiol 2021; 115:1357-1378. [PMID: 33469978 DOI: 10.1111/mmi.14685] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/15/2022]
Abstract
Francisella tularensis is a Gram-negative, intracellular bacterium that causes the zoonotic disease tularemia. Intracellular pathogens, including F. tularensis, have evolved mechanisms to survive in the harsh environment of macrophages and neutrophils, where they are exposed to cell envelope-damaging molecules. The bacterial cell wall, primarily composed of peptidoglycan (PG), maintains cell morphology, structure, and membrane integrity. Intracellular Gram-negative bacteria protect themselves from macrophage and neutrophil killing by recycling and repairing damaged PG--a process that involves over 50 different PG synthesis and recycling enzymes. Here, we identified a PG recycling enzyme, L,D-carboxypeptidase A (LdcA), of F. tularensis that is responsible for converting PG tetrapeptide stems to tripeptide stems. Unlike E. coli LdcA and most other orthologs, F. tularensis LdcA does not localize to the cytoplasm and also exhibits L,D-endopeptidase activity, converting PG pentapeptide stems to tripeptide stems. Loss of F. tularensis LdcA led to altered cell morphology and membrane integrity, as well as attenuation in a mouse pulmonary infection model and in primary and immortalized macrophages. Finally, an F. tularensis ldcA mutant protected mice against virulent Type A F. tularensis SchuS4 pulmonary challenge.
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Affiliation(s)
- Briana Zellner
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
| | - Dominique Mengin-Lecreulx
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Brenden Tully
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
| | | | - Robert Booth
- Department of Pathology, University of Toledo, Toledo, OH, USA
| | - Jason F Huntley
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
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25
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Szulc-Dąbrowska L, Bossowska-Nowicka M, Struzik J, Toka FN. Cathepsins in Bacteria-Macrophage Interaction: Defenders or Victims of Circumstance? Front Cell Infect Microbiol 2020; 10:601072. [PMID: 33344265 PMCID: PMC7746538 DOI: 10.3389/fcimb.2020.601072] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/05/2020] [Indexed: 02/06/2023] Open
Abstract
Macrophages are the first encounters of invading bacteria and are responsible for engulfing and digesting pathogens through phagocytosis leading to initiation of the innate inflammatory response. Intracellular digestion occurs through a close relationship between phagocytic/endocytic and lysosomal pathways, in which proteolytic enzymes, such as cathepsins, are involved. The presence of cathepsins in the endo-lysosomal compartment permits direct interaction with and killing of bacteria, and may contribute to processing of bacterial antigens for presentation, an event necessary for the induction of antibacterial adaptive immune response. Therefore, it is not surprising that bacteria can control the expression and proteolytic activity of cathepsins, including their inhibitors – cystatins, to favor their own intracellular survival in macrophages. In this review, we summarize recent developments in defining the role of cathepsins in bacteria-macrophage interaction and describe important strategies engaged by bacteria to manipulate cathepsin expression and activity in macrophages. Particularly, we focus on specific bacterial species due to their clinical relevance to humans and animal health, i.e., Mycobacterium, Mycoplasma, Staphylococcus, Streptococcus, Salmonella, Shigella, Francisella, Chlamydia, Listeria, Brucella, Helicobacter, Neisseria, and other genera.
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Affiliation(s)
- Lidia Szulc-Dąbrowska
- Division of Immunology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-Szkoła Główna Gospodarstwa Wejskiego, Warsaw, Poland
| | - Magdalena Bossowska-Nowicka
- Division of Immunology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-Szkoła Główna Gospodarstwa Wejskiego, Warsaw, Poland
| | - Justyna Struzik
- Division of Immunology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-Szkoła Główna Gospodarstwa Wejskiego, Warsaw, Poland
| | - Felix N Toka
- Division of Immunology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-Szkoła Główna Gospodarstwa Wejskiego, Warsaw, Poland.,Center for Integrative Mammalian Research, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis
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26
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De Pascalis R, Rossi AP, Mittereder L, Takeda K, Akue A, Kurtz SL, Elkins KL. Production of IFN-γ by splenic dendritic cells during innate immune responses against Francisella tularensis LVS depends on MyD88, but not TLR2, TLR4, or TLR9. PLoS One 2020; 15:e0237034. [PMID: 32745117 PMCID: PMC7398525 DOI: 10.1371/journal.pone.0237034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/17/2020] [Indexed: 12/14/2022] Open
Abstract
Production of IFN-γ is a key innate immune mechanism that limits replication of intracellular bacteria such as Francisella tularensis (Ft) until adaptive immune responses develop. Previously, we demonstrated that the host cell types responsible for IFN-γ production in response to murine Francisella infection include not only natural killer (NK) and T cells, but also a variety of myeloid cells. However, production of IFN-γ by mouse dendritic cells (DC) is controversial. Here, we directly demonstrated substantial production of IFN-γ by DC, as well as hybrid NK-DC, from LVS-infected wild type C57BL/6 or Rag1 knockout mice. We demonstrated that the numbers of conventional DC producing IFN-γ increased progressively over the course of 8 days of LVS infection. In contrast, the numbers of conventional NK cells producing IFN-γ, which represented about 40% of non-B/T IFN-γ-producing cells, peaked at day 4 after LVS infection and declined thereafter. This pattern was similar to that of hybrid NK-DC. To further confirm IFN-γ production by infected cells, DC and neutrophils were sorted from naïve and LVS-infected mice and analyzed for gene expression. Quantification of LVS by PCR revealed the presence of Ft DNA not only in macrophages, but also in highly purified, IFN-γ producing DC and neutrophils. Finally, production of IFN-γ by infected DC was confirmed by immunohistochemistry and confocal microscopy. Notably, IFN-γ production patterns similar to those in wild type mice were observed in cells derived from LVS-infected TLR2, TLR4, and TLR2xTLR9 knockout (KO) mice, but not from MyD88 KO mice. Taken together, these studies demonstrate the pivotal roles of DC and MyD88 in IFN-γ production and in initiating innate immune responses to this intracellular bacterium.
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Affiliation(s)
- Roberto De Pascalis
- Division of Bacterial, Parasitic and Allergenic Products, Laboratory of Mucosal Pathogens and Cellular Immunology, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
- * E-mail: (RDP); (KLE)
| | - Amy P. Rossi
- Division of Bacterial, Parasitic and Allergenic Products, Laboratory of Mucosal Pathogens and Cellular Immunology, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Lara Mittereder
- Division of Bacterial, Parasitic and Allergenic Products, Laboratory of Mucosal Pathogens and Cellular Immunology, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Kazuyo Takeda
- Microscopy and Imaging Core, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Adovi Akue
- Flow Cytometry Core, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Sherry L. Kurtz
- Division of Bacterial, Parasitic and Allergenic Products, Laboratory of Mucosal Pathogens and Cellular Immunology, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Karen L. Elkins
- Division of Bacterial, Parasitic and Allergenic Products, Laboratory of Mucosal Pathogens and Cellular Immunology, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
- * E-mail: (RDP); (KLE)
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27
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OpiA, a Type Six Secretion System Substrate, Localizes to the Cell Pole and Plays a Role in Bacterial Growth and Viability in Francisella tularensis LVS. J Bacteriol 2020; 202:JB.00048-20. [PMID: 32366588 DOI: 10.1128/jb.00048-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/26/2020] [Indexed: 12/19/2022] Open
Abstract
Francisella tularensis is an intracellular pathogen and the causative agent of tularemia. The F. tularensis type six secretion system (T6SS) is required for a number of host-pathogen interactions, including phagolysosomal escape and invasion of erythrocytes. One known effector of the T6SS, OpiA, has recently been shown to be a phosphatidylinositol-3 kinase. To investigate the role of OpiA in erythrocyte invasion, we constructed an opiA-null mutant in the live vaccine strain, F. tularensis LVS. OpiA was not required for erythrocyte invasion; however, deletion of opiA affected growth of F. tularensis LVS in broth cultures in a medium-dependent manner. We also found that opiA influenced cell size, gentamicin sensitivity, bacterial viability, and the lipid content of F. tularensis A fluorescently tagged OpiA (OpiA-emerald-green fluorescent protein [EmGFP]) accumulated at the cell poles of F. tularensis, which is consistent with the location of the T6SS. However, OpiA-EmGFP also exhibited a highly dynamic localization, and this fusion protein was detected in erythrocytes and THP-1 cells in vitro, further supporting that OpiA is secreted. Similar to previous reports with F. novicida, our data demonstrated that opiA had a minimal effect on intracellular replication of F. tularensis in host immune cells in vitro However, THP-1 cells infected with the opiA mutant produced modestly (but significantly) higher levels of the proinflammatory cytokine tumor necrosis factor alpha compared to these host cells infected with wild-type bacteria. We conclude that, in addition to its role in host-pathogen interactions, our results reveal that the function of opiA is central to the biology of F. tularensis bacteria.IMPORTANCE F. tularensis is a pathogenic intracellular pathogen that is of importance for public health and strategic defense. This study characterizes the opiA gene of F. tularensis LVS, an attenuated strain that has been used as a live vaccine but that also shares significant genetic similarity to related Francisella strains that cause human disease. The data presented here provide the first evidence of a T6SS effector protein that affects the physiology of F. tularensis, namely, the growth, cell size, viability, and aminoglycoside resistance of F. tularensis LVS. This study also adds insight into our understanding of OpiA as a determinant of virulence. Finally, the fluorescence fusion constructs presented here will be useful tools for dissecting the role of OpiA in infection.
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28
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Gregory DJ, DeLoid GM, Salmon SL, Metzger DW, Kramnik I, Kobzik L. SON DNA-binding protein mediates macrophage autophagy and responses to intracellular infection. FEBS Lett 2020; 594:2782-2799. [PMID: 32484234 DOI: 10.1002/1873-3468.13851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 05/11/2020] [Indexed: 12/09/2022]
Abstract
Intracellular pathogens affect diverse host cellular defence and metabolic pathways. Here, we used infection with Francisella tularensis to identify SON DNA-binding protein as a central determinant of macrophage activities. RNAi knockdown of SON increases survival of human macrophages following F. tularensis infection or inflammasome stimulation. SON is required for macrophage autophagy, interferon response factor 3 expression, type I interferon response and inflammasome-associated readouts. SON knockdown has gene- and stimulus-specific effects on inflammatory gene expression. SON is required for accurate splicing and expression of GBF1, a key mediator of cis-Golgi structure and function. Chemical GBF1 inhibition has similar effects to SON knockdown, suggesting that SON controls macrophage functions at least in part by controlling Golgi-associated processes.
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Affiliation(s)
- David J Gregory
- Molecular and Physiological Sciences Program, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.,Pediatric Infectious Disease, Massachusetts General Hospital, Boston, MA, USA
| | - Glen M DeLoid
- Molecular and Physiological Sciences Program, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Sharon L Salmon
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
| | - Dennis W Metzger
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, USA
| | - Igor Kramnik
- Pulmonary Center, Department of Medicine, National Emerging Infectious Diseases Laboratories, Boston University School of Medicine, MA, USA
| | - Lester Kobzik
- Molecular and Physiological Sciences Program, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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29
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Zook J, Shekhar M, Hansen D, Conrad C, Grant T, Gupta C, White T, Barty A, Basu S, Zhao Y, Zatsepin N, Ishchenko A, Batyuk A, Gati C, Li C, Galli L, Coe J, Hunter M, Liang M, Weierstall U, Nelson G, James D, Stauch B, Craciunescu F, Thifault D, Liu W, Cherezov V, Singharoy A, Fromme P. XFEL and NMR Structures of Francisella Lipoprotein Reveal Conformational Space of Drug Target against Tularemia. Structure 2020; 28:540-547.e3. [PMID: 32142641 DOI: 10.1016/j.str.2020.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 12/23/2019] [Accepted: 02/13/2020] [Indexed: 02/06/2023]
Abstract
Francisella tularensis is the causative agent for the potentially fatal disease tularemia. The lipoprotein Flpp3 has been identified as a virulence determinant of tularemia with no sequence homology outside the Francisella genus. We report a room temperature structure of Flpp3 determined by serial femtosecond crystallography that exists in a significantly different conformation than previously described by the NMR-determined structure. Furthermore, we investigated the conformational space and energy barriers between these two structures by molecular dynamics umbrella sampling and identified three low-energy intermediate states, transitions between which readily occur at room temperature. We have also begun to investigate organic compounds in silico that may act as inhibitors to Flpp3. This work paves the road to developing targeted therapeutics against tularemia and aides in our understanding of the disease mechanisms of tularemia.
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Affiliation(s)
- James Zook
- Center for Applied Structural Discovery, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Mrinal Shekhar
- Center for Applied Structural Discovery, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; Center for the Development of TherapeuticsThe Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Debra Hansen
- Center for Applied Structural Discovery, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Chelsie Conrad
- Huntsman Cancer Institute, Salt Lake City, UT 84112, USA
| | - Thomas Grant
- Hauptman Woodward Institute, Jacobs School of Medicine and Biomedical Science, SUNY, Buffalo, NY 14260, USA
| | - Chitrak Gupta
- Center for Applied Structural Discovery, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Thomas White
- DESY, Center for Free Electron Laser Science, Hamburg 22607, Germany
| | - Anton Barty
- DESY, Center for Free Electron Laser Science, Hamburg 22607, Germany
| | - Shibom Basu
- European Molecular Biology Laboratory, Grenoble, Grenoble Cedex 9 38042, France
| | - Yun Zhao
- Department of Physics, Arizona State University, Tempe, AZ 85287, USA
| | - Nadia Zatsepin
- Center for Applied Structural Discovery, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Andrii Ishchenko
- Department of Chemistry, Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
| | - Alex Batyuk
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Cornelius Gati
- DESY, Center for Free Electron Laser Science, Hamburg 22607, Germany
| | - Chufeng Li
- Department of Physics, Arizona State University, Tempe, AZ 85287, USA
| | - Lorenzo Galli
- DESY, Center for Free Electron Laser Science, Hamburg 22607, Germany
| | - Jesse Coe
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Mark Hunter
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Meng Liang
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Uwe Weierstall
- Center for Applied Structural Discovery, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Garret Nelson
- Department of Physics, Arizona State University, Tempe, AZ 85287, USA
| | - Daniel James
- Paul Scherrer Institute, 5232 Villigen, Switzerland
| | | | - Felicia Craciunescu
- Center for Applied Structural Discovery, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Darren Thifault
- Center for Applied Structural Discovery, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Wei Liu
- Center for Applied Structural Discovery, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Vadim Cherezov
- Department of Chemistry, Bridge Institute, University of Southern California, Los Angeles, CA 90089, USA
| | - Abhishek Singharoy
- Center for Applied Structural Discovery, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA.
| | - Petra Fromme
- Center for Applied Structural Discovery, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA.
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30
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Stringent response governs the oxidative stress resistance and virulence of Francisella tularensis. PLoS One 2019; 14:e0224094. [PMID: 31648246 PMCID: PMC6812791 DOI: 10.1371/journal.pone.0224094] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 10/04/2019] [Indexed: 01/04/2023] Open
Abstract
Francisella tularensis is a Gram-negative bacterium responsible for causing tularemia in the northern hemisphere. F. tularensis has long been developed as a biological weapon due to its ability to cause severe illness upon inhalation of as few as ten organisms and, based on its potential to be used as a bioterror agent is now classified as a Tier 1 Category A select agent by the CDC. The stringent response facilitates bacterial survival under nutritionally challenging starvation conditions. The hallmark of stringent response is the accumulation of the effector molecules ppGpp and (p)ppGpp known as stress alarmones. The relA and spoT gene products generate alarmones in several Gram-negative bacterial pathogens. RelA is a ribosome-associated ppGpp synthetase that gets activated under amino acid starvation conditions whereas, SpoT is a bifunctional enzyme with both ppGpp synthetase and ppGpp hydrolase activities. Francisella encodes a monofunctional RelA and a bifunctional SpoT enzyme. Previous studies have demonstrated that stringent response under nutritional stresses increases expression of virulence-associated genes encoded on Francisella Pathogenicity Island. This study investigated how stringent response governs the oxidative stress response of F. tularensis. We demonstrate that RelA/SpoT-mediated ppGpp production alters global gene transcriptional profile of F. tularensis in the presence of oxidative stress. The lack of stringent response in relA/spoT gene deletion mutants of F. tularensis makes bacteria more susceptible to oxidants, attenuates survival in macrophages, and virulence in mice. This work is an important step forward towards understanding the complex regulatory network underlying the oxidative stress response of F. tularensis.
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31
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Casulli J, Fife ME, Houston SA, Rossi S, Dow J, Williamson ED, Clark GC, Hussell T, D'Elia RV, Travis MA. CD200R deletion promotes a neutrophil niche for Francisella tularensis and increases infectious burden and mortality. Nat Commun 2019; 10:2121. [PMID: 31073183 PMCID: PMC6509168 DOI: 10.1038/s41467-019-10156-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 04/13/2019] [Indexed: 01/08/2023] Open
Abstract
Pulmonary immune control is crucial for protection against pathogens. Here we identify a pathway that promotes host responses during pulmonary bacterial infection; the expression of CD200 receptor (CD200R), which is known to dampen pulmonary immune responses, promotes effective clearance of the lethal intracellular bacterium Francisella tularensis. We show that depletion of CD200R in mice increases in vitro and in vivo infectious burden. In vivo, CD200R deficiency leads to enhanced bacterial burden in neutrophils, suggesting CD200R normally limits the neutrophil niche for infection. Indeed, depletion of this neutrophil niche in CD200R−/− mice restores F. tularensis infection to levels seen in wild-type mice. Mechanistically, CD200R-deficient neutrophils display significantly reduced reactive oxygen species production (ROS), suggesting that CD200R-mediated ROS production in neutrophils is necessary for limiting F. tularensis colonisation and proliferation. Overall, our data show that CD200R promotes the antimicrobial properties of neutrophils and may represent a novel antibacterial therapeutic target. The authors show that the CD200 receptor (CD200R) promotes effective clearance of pulmonary Francisella tularensis infection in knock out mice. This result is unexpected as CD200R is known to dampen pulmonary immune responses, and these data suggest that the beneficial effect against F. tularensis is due to depletion of a neutrophil niche for the bacterium.
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Affiliation(s)
- J Casulli
- Lydia Becker Institute for Immunology and Inflammation, Manchester, UK.,Wellcome Trust Centre for Cell-Matrix Research, Manchester, UK.,Manchester Collaborative Centre for Inflammation Research (MCCIR), Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - M E Fife
- Lydia Becker Institute for Immunology and Inflammation, Manchester, UK.,Manchester Collaborative Centre for Inflammation Research (MCCIR), Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - S A Houston
- Lydia Becker Institute for Immunology and Inflammation, Manchester, UK.,Wellcome Trust Centre for Cell-Matrix Research, Manchester, UK.,Manchester Collaborative Centre for Inflammation Research (MCCIR), Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - S Rossi
- Lydia Becker Institute for Immunology and Inflammation, Manchester, UK.,Wellcome Trust Centre for Cell-Matrix Research, Manchester, UK.,Manchester Collaborative Centre for Inflammation Research (MCCIR), Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - J Dow
- Lydia Becker Institute for Immunology and Inflammation, Manchester, UK.,Wellcome Trust Centre for Cell-Matrix Research, Manchester, UK.,Manchester Collaborative Centre for Inflammation Research (MCCIR), Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - E D Williamson
- Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury, UK
| | - G C Clark
- Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury, UK
| | - T Hussell
- Lydia Becker Institute for Immunology and Inflammation, Manchester, UK.,Manchester Collaborative Centre for Inflammation Research (MCCIR), Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - R V D'Elia
- Defence Science and Technology Laboratory (Dstl), Porton Down, Salisbury, UK
| | - M A Travis
- Lydia Becker Institute for Immunology and Inflammation, Manchester, UK. .,Wellcome Trust Centre for Cell-Matrix Research, Manchester, UK. .,Manchester Collaborative Centre for Inflammation Research (MCCIR), Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK.
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32
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Chen J, Su FY, Das D, Srinivasan S, Son HN, Lee B, Radella F, Whittington D, Monroe-Jones T, West TE, Convertine AJ, Skerrett SJ, Stayton PS, Ratner DM. Glycan targeted polymeric antibiotic prodrugs for alveolar macrophage infections. Biomaterials 2018; 195:38-50. [PMID: 30610992 DOI: 10.1016/j.biomaterials.2018.10.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 10/03/2018] [Accepted: 10/15/2018] [Indexed: 10/28/2022]
Abstract
Alveolar macrophages resident in the lung are prominent phagocytic effector cells of the pulmonary innate immune response, and paradoxically, are attractive harbors for pathogens. Consequently, facultative intracellular bacteria, such as Francisella tularensis, can cause severe systemic disease and sepsis, with high morbidity and mortality associated with pulmonary infection. Current clinical treatment, which involves exhaustive oral or intravenous antibiotic therapy, has limitations such as systemic toxicity and off-target effects. Pulmonary administration represents a promising alternative to systemic dosing for delivering antibiotics directly to the lung. Here, we present synthesized mannosylated ciprofloxacin polymeric prodrugs for efficient pulmonary delivery, targeting, and subsequent internalization by alveolar macrophages. We demonstrate significant improvement in efficacy against intracellular infections in an otherwise uniformly lethal airborne Francisella murine model (F. novicida). When administered to the lungs of mice in a prophylactic regimen, the mannosylated ciprofloxacin polymeric prodrugs led to 50% survival. In a treatment regimen that was concurrent with infection, the survival of mice increased to 87.5%. Free ciprofloxacin antibiotic was ineffective in both cases. This significant difference in antibacterial efficacy demonstrates the impact of this delivery platform based on improved physiochemical, pharmacokinetic, and pharmacodynamic properties of ciprofloxacin administered via our glycan polymeric prodrug. This modular platform provides a route for overcoming the limitations of free drug and increasing efficacy in treatment of intracellular infection.
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Affiliation(s)
- Jasmin Chen
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Fang-Yi Su
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Debobrato Das
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Selvi Srinivasan
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Hye-Nam Son
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Brian Lee
- Division of Pulmonary, Critical Care & Sleep Medicine, Harborview Medical Center, University of Washington, Seattle, WA 98104, USA
| | - Frank Radella
- Division of Pulmonary, Critical Care & Sleep Medicine, Harborview Medical Center, University of Washington, Seattle, WA 98104, USA
| | - Dale Whittington
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Taylor Monroe-Jones
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - T Eoin West
- Division of Pulmonary, Critical Care & Sleep Medicine, Harborview Medical Center, University of Washington, Seattle, WA 98104, USA
| | | | - Shawn J Skerrett
- Division of Pulmonary, Critical Care & Sleep Medicine, Harborview Medical Center, University of Washington, Seattle, WA 98104, USA
| | - Patrick S Stayton
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.
| | - Daniel M Ratner
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.
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33
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Su FY, Srinivasan S, Lee B, Chen J, Convertine AJ, West TE, Ratner DM, Skerrett SJ, Stayton PS. Macrophage-targeted drugamers with enzyme-cleavable linkers deliver high intracellular drug dosing and sustained drug pharmacokinetics against alveolar pulmonary infections. J Control Release 2018; 287:1-11. [PMID: 30099019 PMCID: PMC6223132 DOI: 10.1016/j.jconrel.2018.08.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/30/2018] [Accepted: 08/07/2018] [Indexed: 12/18/2022]
Abstract
Intracellular bacterial infections localized to the lung alveolar macrophage (AM) remain one of the most challenging settings for antimicrobial therapy. Current systemic antibiotic treatment fails to deliver sustained doses to intracellular bacterial reservoirs, which necessitates prolonged treatment regimens. Herein, we demonstrate a new intracellular enzyme-cleavable polymeric prodrug with tailored ciprofloxacin release profiles in the lungs and AM. The targeted polymeric prodrug, termed "drugamers", incorporates (1) hydrophilic mannose residues to solubilize the antibiotic cargo and to target and enhance AM uptake and intracellular delivery, and (2) enzyme-cleavable linkage chemistry to provide high and sustained intracellular AM drug dosing. Prodrug monomers, derived from the antibiotic ciprofloxacin, were synthesized with either an intracellular protease cleavable dipeptide linker or a hydrolytic phenyl ester linker. RAFT polymerization was used to copolymerize the prodrug monomers and mannose monomer to synthesize well-defined drugamers without requiring a post-polymerization conjugation step. In addition to favorable in vivo safety profiles following intratracheal administration, a single dose of the drugamers sustained ciprofloxacin dosing in lungs and AMs above the minimum inhibitory concentration (MIC) over at least a 48 h period. The enzyme-cleavable therapeutic achieved a >10-fold increase in sustained ciprofloxacin in AM, and maintained a significantly higher whole lung PK as well. Ciprofloxacin dosed in identical fashion displayed rapid clearance with a half-life of approximately 30 min. Notably, inhalation of the mannose-targeted ciprofloxacin drugamers achieved full survival (100%) in a highly lethal mouse model of pneumonic tularemia, contrasted with 0% survival using free ciprofloxacin. These findings demonstrate the versatility of the drugamer platform for engineering the intracellular pharmacokinetic profiles and its strong therapeutic activity in treating pulmonary intracellular infections.
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Affiliation(s)
- Fang-Yi Su
- Department of Bioengineering, University of Washington, Seattle, WA 98195, United States
| | - Selvi Srinivasan
- Department of Bioengineering, University of Washington, Seattle, WA 98195, United States
| | - Brian Lee
- Division of Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, Seattle, WA 98104, United States
| | - Jasmin Chen
- Department of Bioengineering, University of Washington, Seattle, WA 98195, United States
| | - Anthony J Convertine
- Department of Bioengineering, University of Washington, Seattle, WA 98195, United States
| | - Timothy Eoin West
- Division of Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, Seattle, WA 98104, United States; Department of Global Health, University of Washington, Seattle, WA 98195, United States.
| | - Daniel M Ratner
- Department of Bioengineering, University of Washington, Seattle, WA 98195, United States.
| | - Shawn J Skerrett
- Division of Pulmonary and Critical Care Medicine, Harborview Medical Center, University of Washington, Seattle, WA 98104, United States.
| | - Patrick S Stayton
- Department of Bioengineering, University of Washington, Seattle, WA 98195, United States.
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34
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Li F, Li Y, Liang H, Xu T, Kong Y, Huang M, Xiao J, Chen X, Xia H, Wu Y, Zhou Z, Guo X, Hu C, Yang C, Cheng X, Chen C, Qi X. HECTD3 mediates TRAF3 polyubiquitination and type I interferon induction during bacterial infection. J Clin Invest 2018; 128:4148-4162. [PMID: 29920190 DOI: 10.1172/jci120406] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 06/14/2018] [Indexed: 02/06/2023] Open
Abstract
Lysine-63-linked (K63-linked) polyubiquitination of TRAF3 coordinates the engagement of pattern-recognition receptors with recruited adaptor proteins and downstream activator TBK1 in pathways that induce type I IFN. Whether autoubiquitination or other E3 ligases mediate K63-linked TRAF3 polyubiquitination remains unclear. We demonstrated that mice deficient in the E3 ligase gene Hectd3 remarkably increased host defense against infection by intracellular bacteria Francisella novicida, Mycobacterium, and Listeria by limiting bacterial dissemination. In the absence of HECTD3, type I IFN response was impaired during bacterial infection both in vivo and in vitro. HECTD3 regulated type I IFN production by mediating K63-linked polyubiquitination of TRAF3 at residue K138. The catalytic domain of HECTD3 regulated TRAF3 K63 polyubiquitination, which enabled TRAF3-TBK1 complex formation. Our study offers insights into mechanisms of TRAF3 modulation and provides potential therapeutic targets against infections by intracellular bacteria and inflammatory diseases.
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Affiliation(s)
- Fubing Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and
| | - Yang Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and.,Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Huichun Liang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and
| | - Tao Xu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and.,Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Yanjie Kong
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and
| | - Maobo Huang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and
| | - Ji Xiao
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Xi Chen
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and
| | - Houjun Xia
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and
| | - Yingying Wu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and
| | - Zhongmei Zhou
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and
| | - Xiaomin Guo
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and.,Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Chunmiao Hu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and.,Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Chuanyu Yang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and
| | - Xu Cheng
- Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, China
| | - Ceshi Chen
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and
| | - Xiaopeng Qi
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, and.,Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
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35
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Carruthers J, López-García M, Gillard JJ, Laws TR, Lythe G, Molina-París C. A Novel Stochastic Multi-Scale Model of Francisella tularensis Infection to Predict Risk of Infection in a Laboratory. Front Microbiol 2018; 9:1165. [PMID: 30034369 PMCID: PMC6043654 DOI: 10.3389/fmicb.2018.01165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 05/14/2018] [Indexed: 12/30/2022] Open
Abstract
We present a multi-scale model of the within-phagocyte, within-host and population-level infection dynamics of Francisella tularensis, which extends the mechanistic one proposed by Wood et al. (2014). Our multi-scale model incorporates key aspects of the interaction between host phagocytes and extracellular bacteria, accounts for inter-phagocyte variability in the number of bacteria released upon phagocyte rupture, and allows one to compute the probability of response, and mean time until response, of an infected individual as a function of the initial infection dose. A Bayesian approach is applied to parameterize both the within-phagocyte and within-host models using infection data. Finally, we show how dose response probabilities at the individual level can be used to estimate the airborne propagation of Francisella tularensis in indoor settings (such as a microbiology laboratory) at the population level, by means of a deterministic zonal ventilation model.
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Affiliation(s)
- Jonathan Carruthers
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, United Kingdom
| | - Martín López-García
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, United Kingdom
| | - Joseph J. Gillard
- Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | - Thomas R. Laws
- Defence Science and Technology Laboratory, Salisbury, United Kingdom
| | - Grant Lythe
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, United Kingdom
| | - Carmen Molina-París
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds, United Kingdom
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36
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Klonoski JM, Watson T, Bickett TE, Svendsen JM, Gau TJ, Britt A, Nelson JT, Schlenker EH, Chaussee MS, Rynda-Apple A, Huber VC. Contributions of Influenza Virus Hemagglutinin and Host Immune Responses Toward the Severity of Influenza Virus: Streptococcus pyogenes Superinfections. Viral Immunol 2018; 31:457-469. [PMID: 29870311 PMCID: PMC6043403 DOI: 10.1089/vim.2017.0193] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Influenza virus infections can be complicated by bacterial superinfections, which are medically relevant because of a complex interaction between the host, the virus, and the bacteria. Studies to date have implicated several influenza virus genes, varied host immune responses, and bacterial virulence factors, however, the host-pathogen interactions that predict survival versus lethal outcomes remain undefined. Previous work by our group showed that certain influenza viruses could yield a survival phenotype (A/swine/Texas/4199-2/98-H3N2, TX98), whereas others were associated with a lethal phenotype (A/Puerto Rico/8/34-H1N1, PR8). Based on this observation, we developed the hypothesis that individual influenza virus genes could contribute to a superinfection, and that the host response after influenza virus infection could influence superinfection severity. The present study analyzes individual influenza virus gene contributions to superinfection severity using reassortant viruses created using TX98 and PR8 viral genes. Host and pathogen interactions, relevant to survival and lethal phenotypes, were studied with a focus on pathogen clearance, host cellular infiltrates, and cytokine levels after infection. Specifically, we found that the hemagglutinin gene expressed by an influenza virus can contribute to the severity of a secondary bacterial infection, likely through modulation of host proinflammatory responses. Altogether, these results advance our understanding of molecular mechanisms underlying influenza virus-bacteria superinfections and identify viral and corresponding host factors that may contribute to morbidity and mortality.
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Affiliation(s)
- Joshua M. Klonoski
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
| | - Trevor Watson
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
| | - Thomas E. Bickett
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
| | - Joshua M. Svendsen
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
| | - Tonia J. Gau
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
| | - Alexandra Britt
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
| | - Jeff T. Nelson
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
| | - Evelyn H. Schlenker
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
| | - Michael S. Chaussee
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
| | - Agnieszka Rynda-Apple
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana
| | - Victor C. Huber
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
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Detrimental Influence of Alveolar Macrophages on Protective Humoral Immunity during Francisella tularensis SchuS4 Pulmonary Infection. Infect Immun 2018; 86:IAI.00787-17. [PMID: 29311236 DOI: 10.1128/iai.00787-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/02/2018] [Indexed: 01/08/2023] Open
Abstract
Opsonizing antibody is a critical component of the host protective immune response against many respiratory pathogens. However, the role of antibodies in protection against pulmonary infection with highly virulent Francisella tularensis strain SchuS4 is unclear, and the mechanism that allows F. tularensis to evade antibody-mediated bacterial clearance is not fully understood. We have now found that depletion of alveolar macrophages reveals an otherwise cryptic protective effect of opsonizing antibody. While antibody opsonization alone failed to confer any survival benefit against SchuS4 lung infection, significant protection was observed when mice were depleted of alveolar macrophages prior to infection. Blood immune signature analyses and bacterial burden measurements indicated that the treatment regimen blocked establishment of productive, systemic infection. In addition, protection was found to be dependent upon neutrophils. The results show for the first time a protective effect of opsonizing antibodies against highly virulent F. tularensis SchuS4 pulmonary infection through depletion of alveolar macrophages, the primary bacterial reservoir, and prevention of systemic dissemination. These findings have important implications for the potential use of therapeutic antibodies against intracellular pathogens that may escape clearance by residing within mucosal macrophages.
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Lee YT, Ko EJ, Kim KH, Hwang HS, Lee Y, Kwon YM, Kim MC, Lee YN, Jung YJ, Kang SM. Cellular Immune Correlates Preventing Disease Against Respiratory Syncytial Virus by Vaccination with Virus-Like Nanoparticles Carrying Fusion Proteins. J Biomed Nanotechnol 2018; 13:84-98. [PMID: 29302248 DOI: 10.1166/jbn.2017.2341] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cellular immune correlates conferring protection against respiratory syncytial virus (RSV) but preventing vaccine-enhanced respiratory disease largely remain unclear. We investigated cellular immune correlates that contribute to preventing disease against human respiratory syncytial virus (RSV) by nanoparticle vaccine delivery. Formalin-inactivated RSV (FI-RSV) vaccines and virus-like nanoparticles carrying RSV fusion proteins (F VLP) were investigated in mice. The FI-RSV vaccination caused severe weight loss and histopathology by inducing interleukin (IL)-4+, interferon (IFN)-γ+, IL-4+IFN-γ+ CD4+ T cells, eosinophils, and lung plasmacytoid dendritic cells (DCs), CD103+ DCs, and CD11b+ DCs. In contrast, the F VLP-immune mice induced protection against RSV without disease by inducing natural killer cells, activated IFN-γ+, and IFN-γ+ tumor necrosis factor (TNF)-α+ CD8+ T cells in the lung and bronchiolar airways during RSV infection but not disease-inducing DCs and effector T cells. Clodronate-mediated depletion studies provided evidence that alveolar macrophages that were present at high levels in the F VLP-immune mice play a role in modulating protective cellular immune phenotypes. There was an intrinsic difference between the F VLP and FI-RSV treatments in stimulating proinflammatory cytokines. The F VLP nanoparticle vaccination induced distinct innate and adaptive cellular subsets that potentially prevented lung disease after RSV infection.
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Affiliation(s)
- Young-Tae Lee
- Center for Inflammation, Immunity and Infection, Institute of Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Eun-Ju Ko
- Center for Inflammation, Immunity and Infection, Institute of Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA.,Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Ki-Hye Kim
- Center for Inflammation, Immunity and Infection, Institute of Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Hye Suk Hwang
- Center for Inflammation, Immunity and Infection, Institute of Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA.,Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Youri Lee
- Center for Inflammation, Immunity and Infection, Institute of Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA.,Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Young-Man Kwon
- Center for Inflammation, Immunity and Infection, Institute of Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Min-Chul Kim
- Center for Inflammation, Immunity and Infection, Institute of Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA.,Animal and Plant Quarantine Agency, 175 Anyangro, Anyangsi, Gyeonggido, 430-757, Korea
| | - Yu-Na Lee
- Center for Inflammation, Immunity and Infection, Institute of Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Yu-Jin Jung
- Center for Inflammation, Immunity and Infection, Institute of Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA.,Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Sang-Moo Kang
- Center for Inflammation, Immunity and Infection, Institute of Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA.,Department of Biology, Georgia State University, Atlanta, GA 30303, USA
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Zinc Acquisition Mechanisms Differ between Environmental and Virulent Francisella Species. J Bacteriol 2018; 200:JB.00587-17. [PMID: 29109188 PMCID: PMC5786701 DOI: 10.1128/jb.00587-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 10/27/2017] [Indexed: 12/29/2022] Open
Abstract
Zinc is an essential nutrient for bacterial growth. Because host cells can restrict pathogen access to zinc as an antimicrobial defense mechanism, intracellular pathogens such as Francisella must sense their environment and acquire zinc in response. In many bacteria, the conserved transcription factor Zur is a key regulator of zinc acquisition. To identify mechanisms of zinc uptake in Francisella novicida U112, transcriptome sequencing of wild-type and putative zur mutant bacteria was performed. Only three genes were confirmed as directly regulated by Zur and zinc limitation by quantitative reverse transcription-PCR. One of these genes, FTN_0879, is predicted to encode a protein with similarity to the zupT family of zinc transporters, which are not typically regulated by Zur. While a putative znuACB operon encoding a high-affinity zinc transporter was identified in U112, expression of this operon was not controlled by Zur or zinc concentration. Disruption of zupT but not znuA in U112 impaired growth under zinc limitation, suggesting that ZupT is the primary mechanism of zinc acquisition under these conditions. In the virulent Francisella tularensis subsp. tularensis Schu S4 strain, zupT is a pseudogene, and attempts to delete znuA were unsuccessful, suggesting that it is essential in this strain. A reverse TetR repression system was used to knock down the expression of znuA in Schu S4, revealing that znuA is required for growth under zinc limitation and contributes to intracellular growth within macrophages. Overall, this work identifies genes necessary for adaptation to zinc limitation and highlights nutritional differences between environmental and virulent Francisella strains. IMPORTANCEFrancisella tularensis is a tier 1 select agent with a high potential for lethality and no approved vaccine. A better understanding of Francisella virulence factors is required for the development of therapeutics. While acquisition of zinc has been shown to be required for the virulence of numerous intracellular pathogens, zinc uptake has not been characterized in Francisella. This work characterizes the Zur regulon in F. novicida and identifies two transporters that contribute to bacterial growth under zinc limitation. In addition, these data identify differences in mechanisms of zinc uptake and tolerance to zinc limitation between F. tularensis and F. novicida, highlighting the role of znuA in the growth of Schu S4 under zinc limitation.
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Gregory DJ, Kramnik I, Kobzik L. Protection of macrophages from intracellular pathogens by miR-182-5p mimic-a gene expression meta-analysis approach. FEBS J 2017; 285:244-260. [PMID: 29197182 DOI: 10.1111/febs.14348] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 09/29/2017] [Accepted: 11/28/2017] [Indexed: 12/25/2022]
Abstract
The goals of this study were to (a) define which host genes are of particular importance during the interactions between macrophages and intracellular pathogens, and (b) use this knowledge to gain fresh, experimental understanding of how macrophage activities may be manipulated during host defense. We designed an in silico method for meta-analysis of microarray gene expression data, and used this to combine data from 16 different studies of cells in the monocyte-macrophage lineage infected with seven different pathogens. Three thousand four hundred ninety-eight genes were identified, which we call the macrophage intracellular pathogen response (macIPR) gene set. As expected, the macIPR gene set showed a strong bias toward genes previously associated with the immune response. Predicted target sites for miR-182-5p (miR-182) were strongly over-represented among macIPR genes, indicating an unexpected role for miR-182-regulatable genes during intracellular pathogenesis. We therefore transfected primary human alveolar macrophage-like monocyte-derived macrophages from multiple different donors with synthetic miR-182, and found that miR-182 overexpression (a) increases proinflammatory gene induction during infection with Francisella tularensis live vaccine strain (LVS), (b) primes macrophages for increased autophagy, and (c) enhances macrophage control of both gram negative F. tularensisLVS and gram positive Bacillus anthracisANR-1 spores. These data therefore suggest a new application for miR-182 in promoting resistance to intracellular pathogens.
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Affiliation(s)
- David J Gregory
- Molecular and Physiological Sciences Program, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Igor Kramnik
- Pulmonary Center, Department of Medicine, National Emerging Infectious Diseases Laboratories, Boston University School of Medicine, MA, USA
| | - Lester Kobzik
- Molecular and Physiological Sciences Program, Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
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41
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Brock SR, Parmely MJ. Francisella tularensis Confronts the Complement System. Front Cell Infect Microbiol 2017; 7:523. [PMID: 29312899 PMCID: PMC5742141 DOI: 10.3389/fcimb.2017.00523] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/08/2017] [Indexed: 12/30/2022] Open
Abstract
Francisella tularensis has developed a number of effective evasion strategies to counteract host immune defenses, not the least of which is its ability to interact with the complement system to its own advantage. Following exposure of the bacterium to fresh human serum, complement is activated and C3b and iC3b can be found covalently attached to the bacterial surface. However, the lipopolysaccharide and capsule of the F. tularensis cell wall prevent complement-mediated lysis and endow the bacterium with serum resistance. Opsonization of F. tularensis with C3 greatly increases its uptake by human neutrophils, dendritic cells and macrophages. Uptake occurs by an unusual looping morphology in human macrophages. Complement receptor 3 is thought to play an important role in opsonophagocytosis by human macrophages, and signaling through this receptor can antagonize Toll-like receptor 2-initiated macrophage activation. Complement C3 also determines the survival of infected human macrophages and perhaps other cell types. C3-opsonization of F. tularensis subsp. tularensis strain SCHU S4 results in greatly increased death of infected human macrophages, which requires more than complement receptor engagement and is independent of the intracellular replication by the pathogen. Given its entry into the cytosol of host cells, F. tularensis has the potential for a number of other complement-mediated interactions. Studies on the uptake C3-opsonized adenovirus have suggested the existence of a C3 sensing system that initiates cellular responses to cytosolic C3b present on invading microbes. Here we propose that C3 peptides enter the cytosol of human macrophages following phagosome escape of F. tularensis and are recognized as intruding molecular patterns that signal host cell death. With the discovery of new roles for intracellular C3, a better understanding of tularemia pathogenesis is likely to emerge.
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Affiliation(s)
- Susan R Brock
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Michael J Parmely
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS, United States
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Krocova Z, Macela A, Kubelkova K. Innate Immune Recognition: Implications for the Interaction of Francisella tularensis with the Host Immune System. Front Cell Infect Microbiol 2017; 7:446. [PMID: 29085810 PMCID: PMC5650615 DOI: 10.3389/fcimb.2017.00446] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 09/29/2017] [Indexed: 12/11/2022] Open
Abstract
The intracellular bacterial pathogen Francisella tularensis causes serious infectious disease in humans and animals. Moreover, F. tularensis, a highly infectious pathogen, poses a major concern for the public as a bacterium classified under Category A of bioterrorism agents. Unfortunately, research has so far failed to develop effective vaccines, due in part to the fact that the pathogenesis of intracellular bacteria is not fully understood and in part to gaps in our understanding of innate immune recognition processes leading to the induction of adaptive immune response. Recent evidence supports the concept that immune response to external stimuli in the form of bacteria is guided by the primary interaction of the bacterium with the host cell. Based on data from different Francisella models, we present here the basic paradigms of the emerging innate immune recognition concept. According to this concept, the type of cell and its receptor(s) that initially interact with the target constitute the first signaling window; the signals produced in the course of primary interaction of the target with a reacting cell act in a paracrine manner; and the innate immune recognition process as a whole consists in a series of signaling windows modulating adaptive immune response. Finally, the host, in the strict sense, is the interacting cell.
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Affiliation(s)
- Zuzana Krocova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Ales Macela
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
| | - Klara Kubelkova
- Department of Molecular Pathology and Biology, Faculty of Military Health Sciences, University of Defence, Hradec Kralove, Czechia
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43
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Skyberg JA, Lacey CA. Hematopoietic MyD88 and IL-18 are essential for IFN-γ-dependent restriction of type A Francisella tularensis infection. J Leukoc Biol 2017; 102:1441-1450. [PMID: 28951422 DOI: 10.1189/jlb.4a0517-179r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/03/2017] [Accepted: 08/29/2017] [Indexed: 12/11/2022] Open
Abstract
Francisella tularensis is a highly infectious intracellular bacterium that causes the potentially fatal disease tularemia. We used mice with conditional MyD88 deficiencies to investigate cellular and molecular mechanisms by which MyD88 restricts type A F. tularensis infection. F. tularensis-induced weight loss was predominately dependent on MyD88 signaling in nonhematopoietic cells. In contrast, MyD88 signaling in hematopoietic cells, but not in myeloid and dendritic cells, was essential for control of F. tularensis infection in tissue. Myeloid and dendritic cell MyD88 deficiency also did not markedly impair cytokine production during infection. Although the production of IL-12 or -18 was not significantly reduced in hematopoietic MyD88-deficient mice, IFN-γ production was abolished in these animals. In addition, neutralization studies revealed that control of F. tularensis infection mediated by hematopoietic MyD88 was entirely dependent on IFN-γ. Although IL-18 production was not significantly affected by MyD88 deficiency, IL-18 was essential for IFN-γ production and restricted bacterial replication in an IFN-γ-dependent manner. Caspase-1 was also found to be partially necessary for the production of IL-18 and IFN-γ and for control of F. tularensis replication. Our collective data show that the response of leukocytes to caspase-1-dependent IL-18 via MyD88 is critical, whereas MyD88 signaling in myeloid and dendritic cells is dispensable for IFN-γ-dependent control of type A F. tularensis infection.
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Affiliation(s)
- Jerod A Skyberg
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA; and .,Laboratory for Infectious Disease Research, University of Missouri, Columbia, Missouri, USA
| | - Carolyn A Lacey
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA; and.,Laboratory for Infectious Disease Research, University of Missouri, Columbia, Missouri, USA
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44
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Complement C3 as a Prompt for Human Macrophage Death during Infection with Francisella tularensis Strain SCHU S4. Infect Immun 2017; 85:IAI.00424-17. [PMID: 28739830 DOI: 10.1128/iai.00424-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 07/18/2017] [Indexed: 02/06/2023] Open
Abstract
Tularemia is caused by the Gram-negative bacterial pathogen Francisella tularensis Infection of macrophages and their subsequent death are believed to play important roles in the progression of disease. Because complement is a particularly effective opsonin for Francisella, we asked whether complement-dependent uptake of F. tularensis strain SCHU S4 affects the survival of primary human macrophages during infection. Complement component C3 was found to be an essential opsonin in human serum not only for greatly increased uptake of SCHU S4 but also for the induction of macrophage death. Single-cell analysis also revealed that macrophage death did not require a high intracellular bacterial burden. In the presence of C3, macrophage death was observed at 24 h postinfection in a quarter of the macrophages that contained only 1 to 5 bacterial cells. Macrophages infected in the absence of C3 rarely underwent cell death, even when they contained large numbers of bacteria. The need for C3, but not extensive replication of the pathogen, was confirmed by infections with SCHU S4 ΔpurMCD, a mutant capable of phagosome escape but of only limited cytosolic replication. C3-dependent Francisella uptake alone was insufficient to induce macrophage death, as evidenced by the failure of the phagosome escape-deficient mutant SCHU S4 ΔfevR to induce cell death despite opsonization with C3. Together, these findings indicate that recognition of C3-opsonized F. tularensis, but not extensive cytosolic replication, plays an important role in regulating macrophage viability during intracellular infections with type A F. tularensis.
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45
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Kinkead LC, Fayram DC, Allen LAH. Francisella novicida inhibits spontaneous apoptosis and extends human neutrophil lifespan. J Leukoc Biol 2017; 102:815-828. [PMID: 28550119 DOI: 10.1189/jlb.4ma0117-014r] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 04/27/2017] [Accepted: 05/02/2017] [Indexed: 01/09/2023] Open
Abstract
Francisella novicida is a Gram-negative bacterium that is closely related to the highly virulent facultative intracellular pathogen, Francisella tularensis Data published by us and others demonstrate that F. tularensis virulence correlates directly with its ability to impair constitutive apoptosis and extend human neutrophil lifespan. In contrast, F. novicida is attenuated in humans, and the mechanisms that account for this are incompletely defined. Our published data demonstrate that F. novicida binds natural IgG that is present in normal human serum, which in turn, elicits NADPH oxidase activation that does not occur in response to F. tularensis As it is established that phagocytosis and oxidant production markedly accelerate neutrophil death, we predicted that F. novicida may influence the neutrophil lifespan in an opsonin-dependent manner. To test this hypothesis, we quantified bacterial uptake, phosphatidylserine (PS) externalization, and changes in nuclear morphology, as well as the kinetics of procaspase-3, -8, and -9 processing and activation. To our surprise, we discovered that F. novicida not only failed to accelerate neutrophil death but also diminished and delayed apoptosis in a dose-dependent, but opsonin-independent, manner. In keeping with this, studies of conditioned media (CM) showed that neutrophil longevity could be uncoupled from phagocytosis and that F. novicida stimulated neutrophil secretion of CXCL8. Taken together, the results of this study reveal shared and unique aspects of the mechanisms used by Francisella species to manipulate neutrophil lifespan and as such, advance understanding of cell death regulation during infection.
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Affiliation(s)
- Lauren C Kinkead
- Inflammation Program, University of Iowa, Iowa City, Iowa, USA.,Department of Microbiology, University of Iowa, Iowa City, Iowa, USA.,Iowa City VA Medical Center, Iowa City, Iowa, USA
| | - Drew C Fayram
- Inflammation Program, University of Iowa, Iowa City, Iowa, USA.,Department of Microbiology, University of Iowa, Iowa City, Iowa, USA
| | - Lee-Ann H Allen
- Inflammation Program, University of Iowa, Iowa City, Iowa, USA; .,Department of Microbiology, University of Iowa, Iowa City, Iowa, USA.,Iowa City VA Medical Center, Iowa City, Iowa, USA.,Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA; and
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46
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Protective Role for Macrophages in Respiratory Francisella tularensis Infection. Infect Immun 2017; 85:IAI.00064-17. [PMID: 28373354 DOI: 10.1128/iai.00064-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/28/2017] [Indexed: 12/25/2022] Open
Abstract
Francisella tularensis causes lethal pneumonia following infection of the lungs by targeting macrophages for intracellular replication; however, macrophages stimulated with interferon gamma (IFN-γ) can resist infection in vitro We therefore hypothesized that the protective effect of IFN-γ against F. tularensisin vivo requires macrophages receptive to stimulation. We found that the lethality of pulmonary F. tularensis LVS infection was exacerbated under conditions of alveolar macrophage depletion and in mice with a macrophage-specific defect in IFN-γ signaling (termed mice with macrophages insensitive to IFN-γ [MIIG mice]). We previously found that treatment with exogenous interleukin 12 (IL-12) protects against F. tularensis infection; this protection was lost in MIIG mice. MIIG mice also exhibited reduced neutrophil recruitment to the lungs following infection. Systemic neutrophil depletion was found to render wild-type mice highly sensitive to respiratory F. tularensis infection, and depletion beginning at 3 days postinfection led to more pronounced sensitivity than depletion beginning prior to infection. Furthermore, IL-12-mediated protection required NADPH oxidase activity. These results indicate that lung macrophages serve a critical protective role in respiratory F. tularensis LVS infection. Macrophages require IFN-γ signaling to mediate protection, which ultimately results in recruitment of neutrophils to further aid in survival from infection.
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47
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Schmitt DM, Barnes R, Rogerson T, Haught A, Mazzella LK, Ford M, Gilson T, Birch JWM, Sjöstedt A, Reed DS, Franks JM, Stolz DB, Denvir J, Fan J, Rekulapally S, Primerano DA, Horzempa J. The Role and Mechanism of Erythrocyte Invasion by Francisella tularensis. Front Cell Infect Microbiol 2017; 7:173. [PMID: 28536678 PMCID: PMC5423315 DOI: 10.3389/fcimb.2017.00173] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 04/21/2017] [Indexed: 01/06/2023] Open
Abstract
Francisella tularensis is an extremely virulent bacterium that can be transmitted naturally by blood sucking arthropods. During mammalian infection, F. tularensis infects numerous types of host cells, including erythrocytes. As erythrocytes do not undergo phagocytosis or endocytosis, it remains unknown how F. tularensis invades these cells. Furthermore, the consequence of inhabiting the intracellular space of red blood cells (RBCs) has not been determined. Here, we provide evidence indicating that residing within an erythrocyte enhances the ability of F. tularensis to colonize ticks following a blood meal. Erythrocyte residence protected F. tularensis from a low pH environment similar to that of gut cells of a feeding tick. Mechanistic studies revealed that the F. tularensis type VI secretion system (T6SS) was required for erythrocyte invasion as mutation of mglA (a transcriptional regulator of T6SS genes), dotU, or iglC (two genes encoding T6SS machinery) severely diminished bacterial entry into RBCs. Invasion was also inhibited upon treatment of erythrocytes with venom from the Blue-bellied black snake (Pseudechis guttatus), which aggregates spectrin in the cytoskeleton, but not inhibitors of actin polymerization and depolymerization. These data suggest that erythrocyte invasion by F. tularensis is dependent on spectrin utilization which is likely mediated by effectors delivered through the T6SS. Our results begin to elucidate the mechanism of a unique biological process facilitated by F. tularensis to invade erythrocytes, allowing for enhanced colonization of ticks.
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Affiliation(s)
- Deanna M Schmitt
- Department of Natural Sciences and Mathematics, West Liberty UniversityWest Liberty, WV, USA
| | - Rebecca Barnes
- Department of Natural Sciences and Mathematics, West Liberty UniversityWest Liberty, WV, USA
| | - Taylor Rogerson
- Department of Natural Sciences and Mathematics, West Liberty UniversityWest Liberty, WV, USA
| | - Ashley Haught
- Department of Natural Sciences and Mathematics, West Liberty UniversityWest Liberty, WV, USA
| | - Leanne K Mazzella
- Department of Natural Sciences and Mathematics, West Liberty UniversityWest Liberty, WV, USA
| | - Matthew Ford
- Department of Natural Sciences and Mathematics, West Liberty UniversityWest Liberty, WV, USA
| | - Tricia Gilson
- Department of Natural Sciences and Mathematics, West Liberty UniversityWest Liberty, WV, USA
| | - James W-M Birch
- Department of Natural Sciences and Mathematics, West Liberty UniversityWest Liberty, WV, USA
| | - Anders Sjöstedt
- Department of Clinical Microbiology, Clinical Bacteriology, and Laboratory for Molecular Infection Medicine Sweden, Umeå UniversityUmeå, Sweden
| | - Douglas S Reed
- Regional Biocontainment Laboratory, Center for Vaccine Research, University of PittsburghPittsburgh, PA, USA
| | - Jonathan M Franks
- Center for Biologic Imaging, University of Pittsburgh School of MedicinePittsburgh, PA, USA
| | - Donna B Stolz
- Center for Biologic Imaging, University of Pittsburgh School of MedicinePittsburgh, PA, USA
| | - James Denvir
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall UniversityHuntington, WV, USA
| | - Jun Fan
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall UniversityHuntington, WV, USA
| | - Swanthana Rekulapally
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall UniversityHuntington, WV, USA
| | - Donald A Primerano
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall UniversityHuntington, WV, USA
| | - Joseph Horzempa
- Department of Natural Sciences and Mathematics, West Liberty UniversityWest Liberty, WV, USA
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48
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Snyder DT, Hedges JF, Jutila MA. Getting "Inside" Type I IFNs: Type I IFNs in Intracellular Bacterial Infections. J Immunol Res 2017; 2017:9361802. [PMID: 28529959 PMCID: PMC5424489 DOI: 10.1155/2017/9361802] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 03/20/2017] [Accepted: 03/27/2017] [Indexed: 12/23/2022] Open
Abstract
Type I interferons represent a unique and complex group of cytokines, serving many purposes during innate and adaptive immunity. Discovered in the context of viral infections, type I IFNs are now known to have myriad effects in infectious and autoimmune disease settings. Type I IFN signaling during bacterial infections is dependent on many factors including whether the infecting bacterium is intracellular or extracellular, as different signaling pathways are activated. As such, the repercussions of type I IFN induction can positively or negatively impact the disease outcome. This review focuses on type I IFN induction and downstream consequences during infection with the following intracellular bacteria: Chlamydia trachomatis, Listeria monocytogenes, Mycobacterium tuberculosis, Salmonella enterica serovar Typhimurium, Francisella tularensis, Brucella abortus, Legionella pneumophila, and Coxiella burnetii. Intracellular bacterial infections are unique because the bacteria must avoid, circumvent, and even co-opt microbial "sensing" mechanisms in order to reside and replicate within a host cell. Furthermore, life inside a host cell makes intracellular bacteria more difficult to target with antibiotics. Because type I IFNs are important immune effectors, modulating this pathway may improve disease outcomes. But first, it is critical to understand the context-dependent effects of the type I IFN pathway in intracellular bacterial infections.
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Affiliation(s)
- Deann T. Snyder
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | - Jodi F. Hedges
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | - Mark A. Jutila
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
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Ramakrishnan G. Iron and Virulence in Francisella tularensis. Front Cell Infect Microbiol 2017; 7:107. [PMID: 28421167 PMCID: PMC5378763 DOI: 10.3389/fcimb.2017.00107] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/16/2017] [Indexed: 12/12/2022] Open
Abstract
Francisella tularensis, the causative agent of tularemia, is a Gram-negative bacterium that infects a variety of cell types including macrophages, and propagates with great efficiency in the cytoplasm. Iron, essential for key enzymatic and redox reactions, is among the nutrients required to support this pathogenic lifestyle and the bacterium relies on specialized mechanisms to acquire iron within the host environment. Two distinct pathways for iron acquisition are encoded by the F. tularensis genome- a siderophore-dependent ferric iron uptake system and a ferrous iron transport system. Genes of the Fur-regulated fslABCDEF operon direct the production and transport of the siderophore rhizoferrin. Siderophore biosynthesis involves enzymes FslA and FslC, while export across the inner membrane is mediated by FslB. Uptake of the rhizoferrin- ferric iron complex is effected by the siderophore receptor FslE in the outer membrane in a TonB-independent process, and FslD is responsible for uptake across the inner membrane. Ferrous iron uptake relies largely on high affinity transport by FupA in the outer membrane, while the Fur-regulated FeoB protein mediates transport across the inner membrane. FslE and FupA are paralogous proteins, sharing sequence similarity and possibly sharing structural features as well. This review summarizes current knowledge of iron acquisition in this organism and the critical role of these uptake systems in bacterial pathogenicity.
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Affiliation(s)
- Girija Ramakrishnan
- Department of Medicine/Division of Infectious Diseases, University of VirginiaCharlottesville, VA, USA
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Powell DA, Frelinger JA. Efficacy of Resistance to Francisella Imparted by ITY/NRAMP/SLC11A1 Depends on Route of Infection. Front Immunol 2017; 8:206. [PMID: 28360906 PMCID: PMC5350118 DOI: 10.3389/fimmu.2017.00206] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/15/2017] [Indexed: 11/13/2022] Open
Abstract
Natural resistance-associated macrophage protein (NRAMP) encoded by the Slc11a1 gene is a membrane-associated transporter of divalent metal ions. Murine Slc11a1 has two known alleles, a functional Slc11a1Gly169, which is found in DBA2/J, NOD/LtJ, and 129p3/J and related mouse strains, and a non-functional Slc11a1Asp169, that is found in C56Bl/6J (B6) and BALB/cJ mice. B6 mice congenic for Slc11a1Gly169 (B6-Slc11a1G169) are markedly resistant to the intracellular pathogens Salmonella, Leishmania, and Mycobacterium tuberculosis. We examined the host cell response and replication of Francisella in B6-Slc11a1G169 mice. Bone marrow-derived macrophages from either B6-Slc11a1G169 or B6 mice were both effectively invaded by Francisella live vaccine strain (LVS). However, at 16 hours post-infection (hpi), the number of LVS bacteria recovered from B6 macrophages had increased roughly 100-fold, while in B6-Slc11a1G169 mice the number decreased 10-fold. When the mice were challenged intranasally (i.n.) B6 mice lost significant amounts (~15%) of weight, where as B6-Slc11a1G169 mice lost no weight. Three days after infection in B6-Slc11a1G169 mice, we failed to recover viable Francisella from the lungs, livers, or spleens. By contrast, B6 mice had bacterial burdens approaching 1 × 106 CFU/organ in all three organs. To further examine the degree of resistance imparted by Slc11a1Gly169 expression, we challenged mice deficient in TLR2, TLR4, and TLR9, but expressing the functional Slc11a1 (B6-Slc11a1G169Tlr2/4/9−/−). Surprisingly, B6-Slc11a1G169Tlr2/4/9−/− mice had no notable weight loss. Eighty percent of B6-Slc11a1G169Tlr2/4/9−/− mice yielded no detectable Francisella in any organ tested. Additionally, Slc11a1G169 produced little detectable cytokine either in the lung or serum compared to B6 mice. Mice expressing Slc11a1Gly169 survived even high doses (~80 LD50) of LVS inoculation. These data taken together serve to highlight that functional Slc11a1Gly169 can compensate the lack of TLR2/4/9. Thus Slc11a1 is a critical player in murine resistance to pulmonary Francisella infection, but not footpad infection.
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Affiliation(s)
- Daniel A Powell
- Department of Immunobiology, University of Arizona , Tucson, AZ , USA
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