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Li W, Li S, Wang J, Yu M, Yang H, He Z, Tang Y, Liu J, Guo N, Xie D, Liu Z, Zheng K, Xu M, Wu Y. The outer membrane protein Tp92 of Treponema pallidum delays human neutrophil apoptosis via the ERK, PI3K/Akt, and NF-κB pathways. Mol Microbiol 2023; 120:684-701. [PMID: 37718557 DOI: 10.1111/mmi.15164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 09/01/2023] [Accepted: 09/03/2023] [Indexed: 09/19/2023]
Abstract
Syphilis is a persistent sexually transmitted disease caused by infiltration of the elusive pathogen Treponema pallidum. Despite the prevalence of human polymorphonuclear neutrophils (hPMNs) within cutaneous lesions, which are characteristic of incipient syphilis, their role in T. pallidum infection remains unclear. Tp92 is the only T. pallidum helical outer membrane protein that exhibits structural features similar to those of outer membrane proteins in other gram-negative bacteria. However, the functional mechanism of this protein in immune cells remains unclear. Neutrophils are short-lived cells that undergo innate apoptosis in response to external stimuli that typically influence this process. In this study, we determined that Tp92 impedes the activation of procaspase-3 via the ERK MAPK, PI3K/Akt, and NF-κB signaling pathways, consequently suppressing caspase-3 activity within hPMNs, and thereby preventing hPMNs apoptosis. Furthermore, Tp92 could also modulate hPMNs apoptosis by enhancing the expression of the anti-apoptotic protein Mcl-1, stimulating IL-8 secretion, and preserving the mitochondrial membrane potential. These findings provide valuable insights into the molecular mechanisms underlying T. pallidum infection and suggest potential therapeutic targets for syphilis treatment.
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Affiliation(s)
- Weiwei Li
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
- Department of Clinical Laboratory, The Second People's Hospital of Foshan, Foshan, China
| | - Sijia Li
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
| | - Jianye Wang
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
- Key Laboratory of Immune Microenvironment and Disease of the Ministry of Education, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Maoying Yu
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
| | - Hongyu Yang
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
| | - Zhangping He
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
| | - Yuanyuan Tang
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
| | - Jie Liu
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
| | - Ningyuan Guo
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
| | - Dongde Xie
- Department of Clinical Laboratory, The Second People's Hospital of Foshan, Foshan, China
| | - Zhaoping Liu
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
| | - Kang Zheng
- Department of Clinical Laboratory, Hengyang Central Hospital, Hengyang, China
| | - Man Xu
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
| | - Yimou Wu
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical College, Institution of Pathogenic Biology, University of South China, Hengyang, China
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2
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Kinkead LC, Krysa SJ, Allen LAH. Neutrophil Survival Signaling During Francisella tularensis Infection. Front Cell Infect Microbiol 2022; 12:889290. [PMID: 35873156 PMCID: PMC9299441 DOI: 10.3389/fcimb.2022.889290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 06/07/2022] [Indexed: 12/18/2022] Open
Abstract
Neutrophils are the most abundant and shortest-lived leukocytes in humans and tight regulation of neutrophil turnover via constitutive apoptosis is essential for control of infection and resolution of inflammation. Accordingly, aberrant neutrophil turnover is hallmark of many disease states. We have shown in previous work that the intracellular bacterial pathogen Francisella tularensis markedly prolongs human neutrophil lifespan. This is achieved, in part, by changes in neutrophil gene expression. Still unknown is the contribution of major neutrophil pro-survival signaling cascades to this process. The objective of this study was to interrogate the contributions of ERK and p38 MAP kinase, Class I phosphoinositide 3-kinases (PI3K), AKT, and NF-κB to neutrophil survival in our system. We demonstrate that both ERK2 and p38α were activated in F. tularensis-infected neutrophils, but only p38α MAPK was required for delayed apoptosis and the rate of cell death in the absence of infection was unchanged. Apoptosis of both infected and uninfected neutrophils was markedly accelerated by the pan-PI3K inhibitor LY2094002, but AKT phosphorylation was not induced, and neutrophil death was not enhanced by AKT inhibitors. In addition, isoform specific and selective inhibitors revealed a unique role for PI3Kα in neutrophil survival after infection, whereas only simultaneous inhibition of PI3Kα and PI3kδ accelerated death of the uninfected controls. Finally, we show that inhibition of NF-κB triggered rapid death of neutrophil after infection. Thus, we defined roles for p38α, PI3Kα and NF-κB delayed apoptosis of F. tularensis-infected cells and advanced understanding of Class IA PI3K isoform activity in human neutrophil survival.
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Affiliation(s)
- Lauren C. Kinkead
- Inflammation Program, University of Iowa, Iowa City, IA, United States,Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States,Iowa City VA Health Care System, Iowa City, IA, United States
| | - Samantha J. Krysa
- Inflammation Program, University of Iowa, Iowa City, IA, United States,Iowa City VA Health Care System, Iowa City, IA, United States,Molecular Medicine Training Program, University of Iowa, Iowa City, IA, United States
| | - Lee-Ann H. Allen
- Inflammation Program, University of Iowa, Iowa City, IA, United States,Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States,Iowa City VA Health Care System, Iowa City, IA, United States,Molecular Medicine Training Program, University of Iowa, Iowa City, IA, United States,Department of Medicine, Division of Infectious Diseases, 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, Columbia, MO, United States,*Correspondence: Lee-Ann H. Allen,
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3
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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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4
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He Z, Xiao J, Wang J, Lu S, Zheng K, Yu M, Liu J, Wang C, Ding N, Liang M, Wu Y. The Chlamydia psittaci Inclusion Membrane Protein 0556 Inhibits Human Neutrophils Apoptosis Through PI3K/AKT and NF-κB Signaling Pathways. Front Immunol 2021; 12:694573. [PMID: 34484191 PMCID: PMC8414580 DOI: 10.3389/fimmu.2021.694573] [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] [Received: 04/13/2021] [Accepted: 07/23/2021] [Indexed: 01/09/2023] Open
Abstract
Inclusion membrane proteins (Incs) play an important role in the structure and stability of chlamydial inclusion and the interaction between Chlamydia spp. and their hosts. Following Chlamydia infection through the respiratory tract, human polymorphonuclear neutrophils (hPMN) not only act as the primary immune cells reaching the lungs, but also serve as reservoir for Chlamydia. We have previously identified a Chlamydia psittaci hypothetical protein, CPSIT_0556, as a medium expressed inclusion membrane protein. However, the role of inclusion membrane protein, CPSIT_0556 in regulating hPMN functions remains unknown. In the present study, we found that CPSIT_0556 could not only inhibit hPMN apoptosis through the PI3K/Akt and NF-κB signaling pathways by releasing IL-8, but also delays procaspase-3 processing and inhibits caspase-3 activity in hPMN. Up-regulating the expression of anti-apoptotic protein Mcl-1 and down-regulating the expression of pro-apoptotic protein Bax could also inhibit the translocalization of Bax in the cytoplasm into the mitochondria, as well as induce the transfer of p65 NF-κB from the cytoplasm to the nucleus. Overall, our findings demonstrate that CPSIT_0556 could inhibit hPMN apoptosis through PI3K/Akt and NF-κB pathways and provide new insights towards understanding a better understanding of the molecular pathogenesis and immune escape mechanisms of C. psittaci.
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Affiliation(s)
- Zhangping He
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, China
| | - Jian Xiao
- Department of Clinical Laboratory, The Affiliated Nanhua Hospital of University of South China, Hengyang, China
| | - Jianye Wang
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, China
| | - Simin Lu
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, China
| | - Kang Zheng
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, China
| | - Maoying Yu
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, China
| | - Jie Liu
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, China
| | - Chuan Wang
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, China
| | - Nan Ding
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, China
| | - Mingxing Liang
- Department of Clinical Laboratory, The Affiliated Huaihua Hospital of University of South China, Huaihua, China
| | - Yimou Wu
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang, China.,Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang, China
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5
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Pulavendran S, Prasanthi M, Ramachandran A, Grant R, Snider TA, Chow VTK, Malayer JR, Teluguakula N. Production of Neutrophil Extracellular Traps Contributes to the Pathogenesis of Francisella tularemia. Front Immunol 2020; 11:679. [PMID: 32391009 PMCID: PMC7193117 DOI: 10.3389/fimmu.2020.00679] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 03/26/2020] [Indexed: 11/13/2022] Open
Abstract
Francisella tularensis(Ft) is a highly virulent, intracellular Gram-negative bacterial pathogen. Acute Ft infection by aerosol route causes pneumonic tularemia, characterized by nodular hemorrhagic lesions, neutrophil-predominant influx, necrotic debris, fibrin deposition, and severe alveolitis. Ft suppresses activity of neutrophils by impairing their respiratory burst and phagocytic activity. However, the fate of the massive numbers of neutrophils recruited to the infection site is unclear. Here, we show that Ft infection resulted in prominent induction of neutrophil extracellular traps (NETs) within damaged lungs of mice infected with the live attenuated vaccine strain of Ft(Ft-LVS), as well as in the lungs of domestic cats and rabbits naturally infected with Ft. Further, Ft-LVS infection increased lung myeloperoxidase (MPO) activity, which mediates histone protein degradation during NETosis and anchors chromatin scaffolds in NETs. In addition, Ft infection also induced expression of peptidylarginine deiminase 4, an enzyme that causes citrullination of histones during formation of NETs. The released NETs were found largely attached to the alveolar epithelium, and disrupted the thin alveolar epithelial barrier. Furthermore, Ft infection induced a concentration-dependent release of NETs from neutrophils in vitro. Pharmacological blocking of MPO reduced Ft-induced NETs release, whereas addition of H2O2 (a substrate of MPO) significantly augmented NETs release, thus indicating a critical role of MPO in Ft-induced NETs. Although immunofluorescence and electron microscopy revealed that NETs could efficiently trap Ft bacteria, NETs failed to exert bactericidal effects. Taken together, these findings suggest that NETs exacerbate tissue damage in pulmonary Ft infection, and that targeting NETosis may offer novel therapeutic interventions in alleviating Ft-induced tissue damage.
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Affiliation(s)
- Sivasami Pulavendran
- College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, OK, United States
| | - Maram Prasanthi
- College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, OK, United States
| | - Akhilesh Ramachandran
- College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, OK, United States
| | - Rezabek Grant
- College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, OK, United States
| | - Timothy A. Snider
- College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, OK, United States
| | - Vincent T. K. Chow
- Department of Microbiology and Immunology, School of Medicine, National University of Singapore, National University Health System, Singapore, Singapore
| | - Jerry R. Malayer
- College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, OK, United States
| | - Narasaraju Teluguakula
- College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, OK, United States
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6
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Mansour AA, Banik S, Suresh RV, Kaur H, Malik M, McCormick AA, Bakshi CS. An Improved Tobacco Mosaic Virus (TMV)-Conjugated Multiantigen Subunit Vaccine Against Respiratory Tularemia. Front Microbiol 2018; 9:1195. [PMID: 29922267 PMCID: PMC5996085 DOI: 10.3389/fmicb.2018.01195] [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: 08/01/2017] [Accepted: 05/16/2018] [Indexed: 12/22/2022] Open
Abstract
Francisella tularensis, the causative agent of the fatal human disease known as tularemia is classified as a Category A Select Agent by the Centers for Disease Control. No licensed vaccine is currently available for prevention of tularemia in the United States. Previously, we published that a tri-antigen tobacco mosaic virus (TMV) vaccine confers 50% protection in immunized mice against respiratory tularemia caused by F. tularensis. In this study, we refined the TMV-vaccine formulation to improve the level of protection in immunized C57BL/6 mice against respiratory tularemia. We developed a tetra-antigen vaccine by conjugating OmpA, DnaK, Tul4, and SucB proteins of Francisella to TMV. CpG was also included in the vaccine formulation as an adjuvant. Primary intranasal (i.n.) immunization followed by two booster immunizations with the tetra-antigen TMV vaccine protected 100% mice against i.n. 10LD100 challenges dose of F. tularensis live vaccine strain (LVS). Mice receiving three immunization doses of tetra-antigen TMV vaccine showed only transient body weight loss, cleared the infection rapidly, and showed minimal histopathological lesions in lungs, liver, and spleen following a lethal respiratory challenge with F. tularensis LVS. Mice immunized with the tetra-antigen TMV vaccine also induced strong ex vivo recall responses and were protected against a lethal challenge as late as 163 days post-primary immunization. Three immunization with the tetra-antigen TMV vaccine also induced a stronger humoral immune response predominated by IgG1, IgG2b, and IgG2c antibodies than mice receiving only a single or two immunizations. Remarkably, a single dose protected 40% of mice, while two doses protected 80% of mice from lethal pathogen challenge. Immunization of Interferon-gamma (IFN-γ)-deficient mice with the tetra-antigen TMV vaccine demonstrated an absolute requirement of IFN-γ for the generation of protective immune response against a lethal respiratory challenge with F. tularensis LVS. Collectively, this study further demonstrates the feasibility of TMV as an efficient platform for the delivery of multiple F. tularensis antigens and that tetra-antigen TMV vaccine formulation provides complete protection, and induces long-lasting protective and memory immune responses against respiratory tularemia caused by F. tularensis LVS.
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Affiliation(s)
- Ahd A Mansour
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Sukalyani Banik
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Ragavan V Suresh
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Hardeep Kaur
- College of Pharmacy, Touro University California, Vallejo, CA, United States
| | - Meenakshi Malik
- Department of Basic and Clinical Sciences, School of Arts and Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States
| | - Alison A McCormick
- College of Pharmacy, Touro University California, Vallejo, CA, United States
| | - Chandra S Bakshi
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
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7
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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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8
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Chou AY, Kennett NJ, Melillo AA, Elkins KL. Murine survival of infection with Francisella novicida and protection against secondary challenge is critically dependent on B lymphocytes. Microbes Infect 2016; 19:91-100. [PMID: 27965147 DOI: 10.1016/j.micinf.2016.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 10/13/2016] [Accepted: 12/05/2016] [Indexed: 12/18/2022]
Abstract
Respiratory infection of mice with Francisella novicida has recently been used as a model for the highly virulent human pathogen Francisella tularensis. Similar to F. tularensis, even small doses of F. novicida administered by respiratory routes are lethal for inbred laboratory mice. This feature obviously limits study of infection-induced immunity. Parenteral sublethal infections of mice with F. novicida are feasible, but the resulting immune responses are incompletely characterized. Here we use parenteral intradermal (i.d.) and intraperitoneal (i.p.) F. novicida infections of C57BL/6J mice to determine the role of B cells in controlling primary and secondary F. novicida infections. Despite developing comparable levels of F. novicida-primed T cells, B cell knockout mice were much more susceptible to both primary i.d. infection and secondary i.p. challenge than wild type (normal) C57BL/6J mice. Transfer of F. novicida-immune sera to either wild type C57BL/6J mice or to B cell knockout mice did not appreciably impact survival of subsequent lethal F. novicida challenge. However, F. novicida-immune mice that were depleted of T cells after priming but just before challenge survived and cleared secondary i.p. F. novicida challenge. Collectively these results indicate that B cells, if not serum antibodies, play a major role in controlling F. novicida infections in mice.
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Affiliation(s)
- Alicia Y Chou
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Rockville, MD 20852, United States
| | - Nikki J Kennett
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Rockville, MD 20852, United States
| | - Amanda A Melillo
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Rockville, MD 20852, United States
| | - Karen L Elkins
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Rockville, MD 20852, United States.
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9
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Kinkead LC, Allen LAH. Multifaceted effects of Francisella tularensis on human neutrophil function and lifespan. Immunol Rev 2016; 273:266-81. [PMID: 27558340 PMCID: PMC5000853 DOI: 10.1111/imr.12445] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Francisella tularensis in an intracellular bacterial pathogen that causes a potentially lethal disease called tularemia. Studies performed nearly 100 years ago revealed that neutrophil accumulation in infected tissues correlates directly with the extent of necrotic damage during F. tularensis infection. However, the dynamics and details of bacteria-neutrophil interactions have only recently been studied in detail. Herein, we review current understanding regarding the mechanisms that recruit neutrophils to F. tularensis-infected lungs, opsonization and phagocytosis, evasion and inhibition of neutrophil defense mechanisms, as well as the ability of F. tularensis to prolong neutrophil lifespan. In addition, we discuss distinctive features of the bacterium, including its ability to act at a distance to alter overall neutrophil responsiveness to exogenous stimuli, and the evidence which suggests that macrophages and neutrophils play distinct roles in tularemia pathogenesis, such that macrophages are major vehicles for intracellular growth and dissemination, whereas neutrophils drive tissue destruction by dysregulation of the inflammatory response.
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Affiliation(s)
- Lauren C. Kinkead
- Inflammation Program, University of Iowa Iowa City, IA 52242
- Department of Microbiology, University of Iowa Iowa City, IA 52242
| | - Lee-Ann H. Allen
- Inflammation Program, University of Iowa Iowa City, IA 52242
- Department of Microbiology, University of Iowa Iowa City, IA 52242
- Department of Internal Medicine, University of Iowa Iowa City, IA 52242
- VA Medical Center, Iowa City, IA 52242
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10
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Ozanic M, Gobin I, Brezovec M, Marecic V, Trobonjaca Z, Abu Kwaik Y, Santic M. F. novicida-Infected A. castellanii Does Not Enhance Bacterial Virulence in Mice. Front Cell Infect Microbiol 2016; 6:56. [PMID: 27242974 PMCID: PMC4870235 DOI: 10.3389/fcimb.2016.00056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 05/03/2016] [Indexed: 01/02/2023] Open
Abstract
Francisella tularensis is a facultative intracellular bacterium that causes tularemia in humans and animals. Epidemiology of tularemia worldwide is often associated with water-borne transmission, which includes mosquitoes and amoebae as the potential host reservoirs of the bacteria in water environment. In vitro studies showed intracellular replication of F. tularensis within Acanthamoeba castellanii and Hartmanella vermiformis cells. While infection of amoeba by Legionella pneumophila has been shown to enhance infectivity of L. pneumophila the role of F. tularensis-infected protozoa in the pathogenesis of tularemia is not known. We used 6 h coculture of A. castellanii and F. novicida for investigation of the effect of inhaled amoeba on the pathogenesis of tularemia on in vivo model. Balb/c mice were infected intratracheally with F. novicida or with F. novicida-infected A. castellanii. Surprisingly, infection with F. novicida-infected A. castellanii did not lead to bronchopneumonia in Balb/c mice, and Francisella did not disseminate into the liver and spleen. Upon inhalation, F. novicida infects a variety of host cells, though neutrophils are the predominant cells early during infection in the lung infiltrates of pulmonary tularemia. The numbers of neutrophils in the lungs of Balb/c mice were significantly lower in the infection of mice with F. novicida-infected A. castellanii in comparison to group of mice infected only with F. novicida. These results demonstrate that following inoculation of mice with F. novicida-infected A. castellanii, mice did not develop tularemia.
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Affiliation(s)
- Mateja Ozanic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
| | - Ivana Gobin
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
| | - Martin Brezovec
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
| | - Valentina Marecic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
| | - Zlatko Trobonjaca
- Department of Physiology and Immunology, Faculty of Medicine, University of RijekaRijeka, Croatia
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology and Center for Predictive Medicine, College of Medicine, University of LouisvilleLouisville, KY, USA
| | - Marina Santic
- Department of Microbiology and Parasitology, Faculty of Medicine, University of RijekaRijeka, Croatia
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McCracken JM, Kinkead LC, McCaffrey RL, Allen LAH. Francisella tularensis Modulates a Distinct Subset of Regulatory Factors and Sustains Mitochondrial Integrity to Impair Human Neutrophil Apoptosis. J Innate Immun 2016; 8:299-313. [PMID: 26906922 DOI: 10.1159/000443882] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/09/2016] [Indexed: 12/13/2022] Open
Abstract
Tularemia is a disease characterized by profound neutrophil accumulation and tissue destruction. The causative organism, Francisella tularensis, is a facultative intracellular bacterium that replicates in neutrophil cytosol, inhibits caspase activation and profoundly prolongs cell lifespan. Here, we identify unique features of this infection and provide fundamental insight into the mechanisms of apoptosis inhibition. Mitochondria are critical regulators of neutrophil apoptosis. We demonstrate that F. tularensis significantly inhibits Bax translocation and Bid processing during 24-48 h of infection, and in this manner sustains mitochondrial integrity. Downstream of mitochondria, X-linked inhibitor of apoptosis protein (XIAP) and proliferating cell nuclear antigen (PCNA) inhibit caspase-9 and caspase-3 by direct binding. Notably, we find that PCNA disappeared rapidly and selectively from infected cells, thereby demonstrating that it is not essential for neutrophil survival, whereas upregulation of calpastatin correlated with diminished calpain activity and reduced XIAP degradation. In addition, R-roscovitine is a cyclin-dependent kinase inhibitor developed for the treatment of cancer; it also induces neutrophil apoptosis and can promote the resolution of several infectious and inflammatory disorders. We confirm the ability of R-roscovitine to induce neutrophil apoptosis, but also demonstrate that its efficacy is significantly impaired by F. tularensis. Collectively, our findings advance the understanding of neutrophil apoptosis and its capacity to be manipulated by pathogenic bacteria.
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Affiliation(s)
- Jenna M McCracken
- Inflammation Program, University of Iowa and VA Medical Center, Iowa City, Iowa, USA
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Hill TM, Gilchuk P, Cicek BB, Osina MA, Boyd KL, Durrant DM, Metzger DW, Khanna KM, Joyce S. Border Patrol Gone Awry: Lung NKT Cell Activation by Francisella tularensis Exacerbates Tularemia-Like Disease. PLoS Pathog 2015; 11:e1004975. [PMID: 26068662 PMCID: PMC4465904 DOI: 10.1371/journal.ppat.1004975] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/26/2015] [Indexed: 12/19/2022] Open
Abstract
The respiratory mucosa is a major site for pathogen invasion and, hence, a site requiring constant immune surveillance. The type I, semi-invariant natural killer T (NKT) cells are enriched within the lung vasculature. Despite optimal positioning, the role of NKT cells in respiratory infectious diseases remains poorly understood. Hence, we assessed their function in a murine model of pulmonary tularemia—because tularemia is a sepsis-like proinflammatory disease and NKT cells are known to control the cellular and humoral responses underlying sepsis. Here we show for the first time that respiratory infection with Francisella tularensis live vaccine strain resulted in rapid accumulation of NKT cells within the lung interstitium. Activated NKT cells produced interferon-γ and promoted both local and systemic proinflammatory responses. Consistent with these results, NKT cell-deficient mice showed reduced inflammatory cytokine and chemokine response yet they survived the infection better than their wild type counterparts. Strikingly, NKT cell-deficient mice had increased lymphocytic infiltration in the lungs that organized into tertiary lymphoid structures resembling induced bronchus-associated lymphoid tissue (iBALT) at the peak of infection. Thus, NKT cell activation by F. tularensis infection hampers iBALT formation and promotes a systemic proinflammatory response, which exacerbates severe pulmonary tularemia-like disease in mice. NKT cells are innate-like lymphocytes with a demonstrated role in a wide range of diseases. Often cited for their ability to rapidly produce a variety of cytokines upon activation, they have long been appreciated for their ability to “jump-start” the immune system and to shape the quality of both the innate and adaptive response. This understanding of their function has been deduced from in vitro experiments or through the in vivo administration of highly potent, chemically synthesized lipid ligands, which may not necessarily reflect a physiologically relevant response as observed in a natural infection. Using a mouse model of pulmonary tularemia, we report that intranasal infection with the live vaccine strain of F. tularensis rapidly activates NKT cells and promotes systemic inflammation, increased tissue damage, and a dysregulated immune response resulting in increased morbidity and mortality in infected mice. Our data highlight the detrimental effects of NKT cell activation and identify a potential new target for therapies against pulmonary tularemia.
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Affiliation(s)
- Timothy M. Hill
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Pavlo Gilchuk
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Veterans Administration Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
| | - Basak B. Cicek
- Department of Immunology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Maria A. Osina
- Department of Psychology and Human Development, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Kelli L. Boyd
- Veterans Administration Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
| | - Douglas M. Durrant
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Dennis W. Metzger
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York, United States of America
| | - Kamal M. Khanna
- Department of Immunology, University of Connecticut Health Center, Farmington, Connecticut, United States of America
| | - Sebastian Joyce
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Veterans Administration Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
- * E-mail:
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13
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Maurin M. New anti-infective strategies for treatment of tularemia. Front Cell Infect Microbiol 2014; 4:115. [PMID: 25191647 PMCID: PMC4137221 DOI: 10.3389/fcimb.2014.00115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 08/02/2014] [Indexed: 11/13/2022] Open
Affiliation(s)
- Max Maurin
- Centre National de Référence des Francisella, Institut de Biologie et Pathologie, Centre Hospitalier Universitaire de Grenoble Grenoble, France ; Laboratoire Adaptation et Pathogénie des Microorganismes, Université Joseph Fourier - Grenoble 1 Grenoble, France ; Laboratoire Adaptation et Pathogénie des Microorganismes, CNRS/UJF, UMR 5163 Grenoble, France
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