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Carreno-Florez GP, Kocak BR, Hendricks MR, Melvin JA, Mar KB, Kosanovich J, Cumberland RL, Delgoffe GM, Shiva S, Empey KM, Schoggins JW, Bomberger JM. Interferon signaling drives epithelial metabolic reprogramming to promote secondary bacterial infection. PLoS Pathog 2023; 19:e1011719. [PMID: 37939149 PMCID: PMC10631704 DOI: 10.1371/journal.ppat.1011719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/28/2023] [Indexed: 11/10/2023] Open
Abstract
Clinical studies report that viral infections promote acute or chronic bacterial infections at multiple host sites. These viral-bacterial co-infections are widely linked to more severe clinical outcomes. In experimental models in vitro and in vivo, virus-induced interferon responses can augment host susceptibility to secondary bacterial infection. Here, we used a cell-based screen to assess 389 interferon-stimulated genes (ISGs) for their ability to induce chronic Pseudomonas aeruginosa infection. We identified and validated five ISGs that were sufficient to promote bacterial infection. Furthermore, we dissected the mechanism of action of hexokinase 2 (HK2), a gene involved in the induction of aerobic glycolysis, commonly known as the Warburg effect. We report that HK2 upregulation mediates the induction of Warburg effect and secretion of L-lactate, which enhances chronic P. aeruginosa infection. These findings elucidate how the antiviral immune response renders the host susceptible to secondary bacterial infection, revealing potential strategies for viral-bacterial co-infection treatment.
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Affiliation(s)
- Grace P. Carreno-Florez
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Brian R. Kocak
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Matthew R. Hendricks
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Jeffrey A. Melvin
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Katrina B. Mar
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Jessica Kosanovich
- Department of Pharmacy and Therapeutics and Center for Clinical Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, Pennsylvania, United States of America
| | - Rachel L. Cumberland
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Greg M. Delgoffe
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Sruti Shiva
- Department of Pharmacology and Chemical Biology and Vascular Medicine Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Kerry M. Empey
- Department of Pharmacy and Therapeutics and Center for Clinical Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, Pennsylvania, United States of America
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - John W. Schoggins
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Jennifer M. Bomberger
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
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2
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Charpentier LA, Dolben EF, Hendricks MR, Hogan DA, Bomberger JM, Stanton BA. Bacterial Outer Membrane Vesicles and Immune Modulation of the Host. Membranes (Basel) 2023; 13:752. [PMID: 37755174 PMCID: PMC10536716 DOI: 10.3390/membranes13090752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/18/2023] [Accepted: 08/22/2023] [Indexed: 09/28/2023]
Abstract
This article reviews the role of outer membrane vesicles (OMVs) in mediating the interaction between Gram-negative bacteria and their human hosts. OMVs are produced by a diverse range of Gram-negative bacteria during infection and play a critical role in facilitating host-pathogen interactions without requiring direct cell-to-cell contact. This article describes the mechanisms by which OMVs are formed and subsequently interact with host cells, leading to the transport of microbial protein virulence factors and short interfering RNAs (sRNA) to their host targets, exerting their immunomodulatory effects by targeting specific host signaling pathways. Specifically, this review highlights mechanisms by which OMVs facilitate chronic infection through epigenetic modification of the host immune response. Finally, this review identifies critical knowledge gaps in the field and offers potential avenues for future OMV research, specifically regarding rigor and reproducibility in OMV isolation and characterization methods.
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Affiliation(s)
- Lily A. Charpentier
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; (L.A.C.); (E.F.D.); (D.A.H.); (J.M.B.)
| | - Emily F. Dolben
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; (L.A.C.); (E.F.D.); (D.A.H.); (J.M.B.)
| | - Matthew R. Hendricks
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA;
| | - Deborah A. Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; (L.A.C.); (E.F.D.); (D.A.H.); (J.M.B.)
| | - Jennifer M. Bomberger
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; (L.A.C.); (E.F.D.); (D.A.H.); (J.M.B.)
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA;
| | - Bruce A. Stanton
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA; (L.A.C.); (E.F.D.); (D.A.H.); (J.M.B.)
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3
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Haas AL, Zemke AC, Melvin JA, Armbruster CR, Hendricks MR, Moore J, Nouraie SM, Thibodeau PH, Lee SE, Bomberger JM. Iron bioavailability regulates Pseudomonas aeruginosa interspecies interactions through type VI secretion expression. Cell Rep 2023; 42:112270. [PMID: 36930643 PMCID: PMC10586262 DOI: 10.1016/j.celrep.2023.112270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/16/2022] [Accepted: 03/01/2023] [Indexed: 03/18/2023] Open
Abstract
The cystic fibrosis (CF) respiratory tract harbors pathogenic bacteria that cause life-threatening chronic infections. Of these, Pseudomonas aeruginosa becomes increasingly dominant with age and is associated with worsening lung function and declining microbial diversity. We aimed to understand why P. aeruginosa dominates over other pathogens to cause worsening disease. Here, we show that P. aeruginosa responds to dynamic changes in iron concentration, often associated with viral infection and pulmonary exacerbations, to become more competitive via expression of the TseT toxic effector. However, this behavior can be therapeutically targeted using the iron chelator deferiprone to block TseT expression and competition. Overall, we find that iron concentration and TseT expression significantly correlate with microbial diversity in the respiratory tract of people with CF. These findings improve our understanding of how P. aeruginosa becomes increasingly dominant with age in people with CF and provide a therapeutically targetable pathway to help prevent this shift.
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Affiliation(s)
- Allison L Haas
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Anna C Zemke
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - Jeffrey A Melvin
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Catherine R Armbruster
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Matthew R Hendricks
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - John Moore
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - Seyed Mehdi Nouraie
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - Patrick H Thibodeau
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Stella E Lee
- Division of Otolaryngology, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Jennifer M Bomberger
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15219, USA.
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4
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Abstract
Type I and III interferons (IFNs) drive effective antiviral functions but differentially affect tissue homeostasis. Using mouse models of severe inflammation, Broggi et al. and Major et al. report in Science that type III IFNs disrupt epithelial cell proliferation and differentiation in the lung.
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Affiliation(s)
| | - Ram Savan
- Department of Immunology, University of Washington, Seattle, WA 98109, USA.
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Hendricks MR, Lane S, Melvin JA, Ouyang Y, Stolz DB, Williams JV, Sadovsky Y, Bomberger JM. Extracellular vesicles promote transkingdom nutrient transfer during viral-bacterial co-infection. Cell Rep 2021; 34:108672. [PMID: 33503419 PMCID: PMC7918795 DOI: 10.1016/j.celrep.2020.108672] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 03/10/2020] [Accepted: 12/30/2020] [Indexed: 01/28/2023] Open
Abstract
Extracellular vesicles (EVs) are increasingly appreciated as a mechanism of communication among cells that contribute to many physiological processes. Although EVs can promote either antiviral or proviral effects during viral infections, the role of EVs in virus-associated polymicrobial infections remains poorly defined. We report that EVs secreted from airway epithelial cells during respiratory viral infection promote secondary bacterial growth, including biofilm biogenesis, by Pseudomonas aeruginosa. Respiratory syncytial virus (RSV) increases the release of the host iron-binding protein transferrin on the extravesicular face of EVs, which interact with P. aeruginosa biofilms to transfer the nutrient iron and promote bacterial biofilm growth. Vesicular delivery of iron by transferrin more efficiently promotes P. aeruginosa biofilm growth than soluble holo-transferrin delivered alone. Our findings indicate that EVs are a nutrient source for secondary bacterial infections in the airways during viral infection and offer evidence of transkingdom communication in the setting of polymicrobial infections.
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Affiliation(s)
- Matthew R Hendricks
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Sidney Lane
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA; Program in Microbiology and Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Jeffrey A Melvin
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Yingshi Ouyang
- Magee-Womens Research Institute, Department of OBGYN and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Donna B Stolz
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - John V Williams
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - Yoel Sadovsky
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA; Magee-Womens Research Institute, Department of OBGYN and Reproductive Sciences, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jennifer M Bomberger
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA.
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6
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Forero A, Ozarkar S, Li H, Lee CH, Hemann EA, Nadjsombati MS, Hendricks MR, So L, Green R, Roy CN, Sarkar SN, von Moltke J, Anderson SK, Gale M, Savan R. Differential Activation of the Transcription Factor IRF1 Underlies the Distinct Immune Responses Elicited by Type I and Type III Interferons. Immunity 2019; 51:451-464.e6. [PMID: 31471108 DOI: 10.1016/j.immuni.2019.07.007] [Citation(s) in RCA: 139] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 05/20/2019] [Accepted: 07/25/2019] [Indexed: 12/21/2022]
Abstract
Type I and III interferons (IFNs) activate similar downstream signaling cascades, but unlike type I IFNs, type III IFNs (IFNλ) do not elicit strong inflammatory responses in vivo. Here, we examined the molecular mechanisms underlying this disparity. Type I and III IFNs displayed kinetic differences in expression of IFN-stimulated genes and proinflammatory responses, with type I IFNs preferentially stimulating expression of the transcription factor IRF1. Type III IFNs failed to induce IRF1 expression because of low IFNλ receptor abundance and insufficient STAT1 activation on epithelial cells and thus did not activate the IRF1 proinflammatory gene program. Rather, IFNλ stimulation preferentially induced factors implicated in tissue repair. Our findings suggest that IFN receptor compartmentalization and abundance confer a spatiotemporal division of labor where type III IFNs control viral spread at the site of the infection while restricting tissue damage; the transient induction of inflammatory responses by type I IFNs recruits immune effectors to promote protective immunity.
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Affiliation(s)
- Adriana Forero
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Snehal Ozarkar
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Hongchuan Li
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Chia Heng Lee
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Emily A Hemann
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Marija S Nadjsombati
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Matthew R Hendricks
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Lomon So
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Richard Green
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA; Center for Innate Immunity and Immune Disease, University of Washington, Seattle, WA 98109, USA
| | - Chandra N Roy
- University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA
| | | | - Jakob von Moltke
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Stephen K Anderson
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA; Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Michael Gale
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA; Center for Innate Immunity and Immune Disease, University of Washington, Seattle, WA 98109, USA
| | - Ram Savan
- Department of Immunology, School of Medicine, University of Washington, Seattle, WA 98109, USA; Center for Innate Immunity and Immune Disease, University of Washington, Seattle, WA 98109, USA.
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7
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Conti HR, Bruno VM, Childs EE, Daugherty S, Hunter JP, Mengesha BG, Saevig DL, Hendricks MR, Coleman BM, Brane L, Solis N, Cruz JA, Verma AH, Garg AV, Hise AG, Richardson JP, Naglik JR, Filler SG, Kolls JK, Sinha S, Gaffen SL. IL-17 Receptor Signaling in Oral Epithelial Cells Is Critical for Protection against Oropharyngeal Candidiasis. Cell Host Microbe 2016; 20:606-617. [PMID: 27923704 DOI: 10.1016/j.chom.2016.10.001] [Citation(s) in RCA: 126] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Revised: 08/16/2016] [Accepted: 09/21/2016] [Indexed: 12/19/2022]
Abstract
Signaling through the IL-17 receptor (IL-17R) is required to prevent oropharyngeal candidiasis (OPC) in mice and humans. However, the IL-17-responsive cell type(s) that mediate protection are unknown. Using radiation chimeras, we were able to rule out a requirement for IL-17RA in the hematopoietic compartment. We saw remarkable concordance of IL-17-controlled gene expression in C. albicans-infected human oral epithelial cells (OECs) and in tongue tissue from mice with OPC. To interrogate the role of the IL-17R in OECs, we generated mice with conditional deletion of IL-17RA in superficial oral and esophageal epithelial cells (Il17raΔK13). Following oral Candida infection, Il17raΔK13 mice exhibited fungal loads and weight loss indistinguishable from Il17ra-/- mice. Susceptibility in Il17raΔK13 mice correlated with expression of the antimicrobial peptide β-defensin 3 (BD3, Defb3). Consistently, Defb3-/- mice were susceptible to OPC. Thus, OECs dominantly control IL-17R-dependent responses to OPC through regulation of BD3 expression.
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Affiliation(s)
- Heather R Conti
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Biological Sciences, University of Toledo, Toledo, OH 43606, USA.
| | - Vincent M Bruno
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Erin E Childs
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Sean Daugherty
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Joseph P Hunter
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606, USA
| | - Bemnet G Mengesha
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606, USA
| | - Danielle L Saevig
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606, USA
| | - Matthew R Hendricks
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Bianca M Coleman
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Lucas Brane
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Norma Solis
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - J Agustin Cruz
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Akash H Verma
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Abhishek V Garg
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Amy G Hise
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA; Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Jonathan P Richardson
- Department of Mucosal and Salivary Biology, King's College London, London SE1 1UL, UK
| | - Julian R Naglik
- Department of Mucosal and Salivary Biology, King's College London, London SE1 1UL, UK
| | - Scott G Filler
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Jay K Kolls
- Richard King Mellon Foundation for Pediatric Research, Children's Hospital of UPMC, Pittsburgh, PA 15224, USA
| | - Satrajit Sinha
- Department of Biochemistry, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
| | - Sarah L Gaffen
- Division of Rheumatology and Clinical Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Mucosal and Salivary Biology, King's College London, London SE1 1UL, UK.
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8
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Abstract
Due to evolutionary pressure, there are many complex interactions at the interface between pathogens and eukaryotic host cells wherein host cells attempt to clear invading microorganisms and pathogens counter these mechanisms to colonize and invade host tissues. One striking observation from studies focused on this interface is that pathogens have multiple mechanisms to modulate and disrupt normal cellular physiology to establish replication niches and avoid clearance. The precision by which pathogens exert their effects on host cells makes them excellent tools to answer questions about cell physiology of eukaryotic cells. Furthermore, an understanding of these mechanisms at the host-pathogen interface will benefit our understanding of how pathogens cause disease. In this review, we describe a few examples of how pathogens disrupt normal cellular physiology and protein trafficking at epithelial cell barriers to underscore how pathogens modulate cellular processes to cause disease and how this knowledge has been utilized to learn about cellular physiology.
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Affiliation(s)
- Matthew R Hendricks
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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Allain JP, Nieto M, Hendricks MR, Plotkin P, Harilal SS, Hassanein A. IMPACT: a facility to study the interaction of low-energy intense particle beams with dynamic heterogeneous surfaces. Rev Sci Instrum 2007; 78:113105. [PMID: 18052463 DOI: 10.1063/1.2805677] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The Interaction of Materials with Particles and Components Testing (IMPACT) experimental facility is furnished with multiple ion sources and in situ diagnostics to study the modification of surfaces undergoing physical, chemical, and electronic changes during exposure to energetic particle beams. Ion beams with energies in the range between 20 and 5000 eV can bombard samples at flux levels in the range of 10(10)-10(15) cm(-2) s(-1); parameters such as ion angle of incidence and exposed area are also controllable during the experiment. IMPACT has diagnostics that allow full characterization of the beam, including a Faraday cup, a beam imaging system, and a retarding field energy analyzer. IMPACT is equipped with multiple diagnostics, such as electron (Auger, photoelectron) and ion scattering spectroscopies that allow different probing depths of the sample to monitor compositional changes in multicomponent and/or layered targets. A unique real-time erosion diagnostic based on a dual quartz crystal microbalance measures deposition from an eroding surface with rates smaller than 0.01 nm/s, which can be converted to a sputter yield measurement. The monitoring crystal can be rotated and placed in the target position so that the deposited material on the quartz crystal oscillator surface can be characterized without transfer outside of the vacuum chamber.
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Affiliation(s)
- J P Allain
- Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, Illinois 60439, USA.
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