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Schneider P, Wander P, Arentsen-Peters STCJM, Vrenken KS, Rockx-Brouwer D, Adriaanse FRS, Hoeve V, Paassen I, Drost J, Pieters R, Stam RW. CRISPR-Cas9 Library Screening Identifies Novel Molecular Vulnerabilities in KMT2A-Rearranged Acute Lymphoblastic Leukemia. Int J Mol Sci 2023; 24:13207. [PMID: 37686014 PMCID: PMC10487613 DOI: 10.3390/ijms241713207] [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: 07/02/2023] [Revised: 08/11/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
In acute lymphoblastic leukemia (ALL), chromosomal translocations involving the KMT2A gene represent highly unfavorable prognostic factors and most commonly occur in patients less than 1 year of age. Rearrangements of the KMT2A gene drive epigenetic changes that lead to aberrant gene expression profiles that strongly favor leukemia development. Apart from this genetic lesion, the mutational landscape of KMT2A-rearranged ALL is remarkably silent, providing limited insights for the development of targeted therapy. Consequently, identifying potential therapeutic targets often relies on differential gene expression, yet the inhibition of these genes has rarely translated into successful therapeutic strategies. Therefore, we performed CRISPR-Cas9 knock-out screens to search for genetic dependencies in KMT2A-rearranged ALL. We utilized small-guide RNA libraries directed against the entire human epigenome and kinome in various KMT2A-rearranged ALL, as well as wild-type KMT2A ALL cell line models. This screening approach led to the discovery of the epigenetic regulators ARID4B and MBD3, as well as the receptor kinase BMPR2 as novel molecular vulnerabilities and attractive therapeutic targets in KMT2A-rearranged ALL.
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Affiliation(s)
- Pauline Schneider
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
| | - Priscilla Wander
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
| | | | - Kirsten S. Vrenken
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
| | | | | | - Veerle Hoeve
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
| | - Irene Paassen
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
| | - Jarno Drost
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
- Oncode Institute, 3521 AL Utrecht, The Netherlands
| | - Rob Pieters
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
| | - Ronald W. Stam
- Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
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van den Braak WJP, Monica B, Limpens D, Rockx-Brouwer D, de Boer M, Oosterhoff D. Construction of a Vero Cell Line Expressing Human ICAM1 for the Development of Rhinovirus Vaccines. Viruses 2022; 14:v14102235. [PMID: 36298792 PMCID: PMC9607643 DOI: 10.3390/v14102235] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/04/2022] [Accepted: 10/07/2022] [Indexed: 11/16/2022] Open
Abstract
Human rhinoviruses (HRVs) are small non-enveloped RNA viruses that belong to the Enterovirus genus within the Picornaviridae family and are known for causing the common cold. Though symptoms are generally mild in healthy individuals, the economic burden associated with HRV infection is significant. A vaccine could prevent disease. The Vero-cell-based viral vaccine platform technology was considered for such vaccine development. Unfortunately, most HRV strains are unable to propagate on Vero cells due to a lack of the major receptor of HRV group A and B, intercellular adhesion molecule (ICAM1, also known as CD54). Therefore, stable human ICAM1 expressing Vero cell clones were generated by transfecting the ICAM1 gene in Vero cells and selecting clones that overexpressed ICAM1 on the cell surface. Cell banks were made and expression of ICAM1 was stable for at least 30 passages. The Vero_ICAM1 cells and parental Vero cells were infected with four HRV prototypes, B14, A16, B37 and A57. Replication of all four viruses was detected in Vero_ICAM1, but not in the parental Vero cells. Altogether, Vero cells expressing ICAM1 could efficiently propagate the tested HRV strains. Therefore, ICAM1-expressing cells could be a useful tool for the development and future production of polyvalent HRV vaccines or other viruses that use ICAM1 as a receptor.
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Raeven RHM, Rockx-Brouwer D, Kanojia G, van der Maas L, Bindels THE, Ten Have R, van Riet E, Metz B, Kersten GFA. Intranasal immunization with outer membrane vesicle pertussis vaccine confers broad protection through mucosal IgA and Th17 responses. Sci Rep 2020; 10:7396. [PMID: 32355188 PMCID: PMC7192948 DOI: 10.1038/s41598-020-63998-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/08/2020] [Indexed: 12/15/2022] Open
Abstract
A vaccine based on outer membrane vesicles of pertussis (omvPV) is protective in a mouse-challenge model and induces a broad antibody and mixed Th1/Th2/Th17 response against multiple antigens following subcutaneous immunization. However, this route did not result in mucosal immunity and did not prevent nasopharyngeal colonization. In this study, we explored the potential of intranasal immunization with omvPV. Only intranasal immunization induced strong mucosal immune responses that encompasses enhanced pulmonary and nasal IgA antibody levels, mainly directed against Vag8 and LPS. Furthermore, high numbers of IgA- and IgG-producing plasma cells were detected as well as lung-resident IgA memory B-cells. Finally, only intranasal immunization induced pulmonary Th1/Th17-related cytokine responses. The magnitude and type of systemic immunity was comparable between both routes and included high systemic IgG antibody levels, strong IgG-producing plasma cell responses, memory B-cells residing in the spleen and systemic Th1/Th2/Th17-related cytokine responses. Importantly, only intranasal immunization prevented colonization in both the lungs and the nasal cavity. In conclusion, intranasal omvPV immunization induces mucosal IgA and Th17-mediated responses without influencing the systemic immunity profile. These responses resulted in prevention of Bordetella pertussis colonization in the respiratory tract, including the nasal cavity, thereby potentially preventing transmission.
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Affiliation(s)
- René H M Raeven
- Intravacc (Institute for Translational Vaccinology), Bilthoven, The Netherlands.
| | | | - Gaurav Kanojia
- Intravacc (Institute for Translational Vaccinology), Bilthoven, The Netherlands
| | | | - Tim H E Bindels
- Intravacc (Institute for Translational Vaccinology), Bilthoven, The Netherlands
| | - Rimko Ten Have
- Intravacc (Institute for Translational Vaccinology), Bilthoven, The Netherlands
| | - Elly van Riet
- Intravacc (Institute for Translational Vaccinology), Bilthoven, The Netherlands
| | - Bernard Metz
- Intravacc (Institute for Translational Vaccinology), Bilthoven, The Netherlands
| | - Gideon F A Kersten
- Intravacc (Institute for Translational Vaccinology), Bilthoven, The Netherlands
- Division of Drug Delivery Technology, Leiden Academic Center for Drug Research, Leiden University, Leiden, The Netherlands
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Warmbrod KL, Patterson EI, Kautz TF, Stanton A, Rockx-Brouwer D, Kalveram BK, Khanipov K, Thangamani S, Fofanov Y, Forrester NL. Viral RNA-dependent RNA polymerase mutants display an altered mutation spectrum resulting in attenuation in both mosquito and vertebrate hosts. PLoS Pathog 2019; 15:e1007610. [PMID: 30947291 PMCID: PMC6467425 DOI: 10.1371/journal.ppat.1007610] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 04/16/2019] [Accepted: 01/31/2019] [Indexed: 02/06/2023] Open
Abstract
The presence of bottlenecks in the transmission cycle of many RNA viruses leads to a severe reduction of number of virus particles and this occurs multiple times throughout the viral transmission cycle. Viral replication is then necessary for regeneration of a diverse mutant swarm. It is now understood that any perturbation of the mutation frequency either by increasing or decreasing the accumulation of mutations in an RNA virus results in attenuation of the virus. To determine if altering the rate at which a virus accumulates mutations decreases the probability of a successful virus infection due to issues traversing host bottlenecks, a series of mutations in the RNA-dependent RNA polymerase of Venezuelan equine encephalitis virus (VEEV), strain 68U201, were tested for mutation rate changes. All RdRp mutants were attenuated in both the mosquito and vertebrate hosts, while showing no attenuation during in vitro infections. The rescued viruses containing these mutations showed some evidence of change in fidelity, but the phenotype was not sustained following passaging. However, these mutants did exhibit changes in the frequency of specific types of mutations. Using a model of mutation production, these changes were shown to decrease the number of stop codons generated during virus replication. This suggests that the observed mutant attenuation in vivo may be due to an increase in the number of unfit genomes, which may be normally selected against by the accumulation of stop codons. Lastly, the ability of these attenuated viruses to transition through a bottleneck in vivo was measured using marked virus clones. The attenuated viruses showed an overall reduction in the number of marked clones for both the mosquito and vertebrate hosts, as well as a reduced ability to overcome the known bottlenecks in the mosquito. This study demonstrates that any perturbation of the optimal mutation frequency whether through changes in fidelity or by alterations in the mutation frequency of specific nucleotides, has significant deleterious effects on the virus, especially in the presence of host bottlenecks.
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Affiliation(s)
- K. Lane Warmbrod
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Edward I. Patterson
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Tiffany F. Kautz
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Adam Stanton
- School of Computing and Mathematics, University of Keele, Keele, United Kingdom
| | - Dedeke Rockx-Brouwer
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Birte K. Kalveram
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Kamil Khanipov
- Sealy Center for Structural Biology and Molecular Biophysics, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Saravanan Thangamani
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Yuriy Fofanov
- Sealy Center for Structural Biology and Molecular Biophysics, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Naomi L. Forrester
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
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Patterson EI, Khanipov K, Rojas MM, Kautz TF, Rockx-Brouwer D, Golovko G, Albayrak L, Fofanov Y, Forrester NL. Mosquito bottlenecks alter viral mutant swarm in a tissue and time-dependent manner with contraction and expansion of variant positions and diversity. Virus Evol 2018; 4:vey001. [PMID: 29479479 PMCID: PMC5814806 DOI: 10.1093/ve/vey001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Viral diversity is theorized to play a significant role during virus infections, particularly for arthropod-borne viruses (arboviruses) that must infect both vertebrate and invertebrate hosts. To determine how viral diversity influences mosquito infection and dissemination Culex taeniopus mosquitoes were infected with the Venezuelan equine encephalitis virus endemic strain 68U201. Bodies and legs/wings of the mosquitoes were collected individually and subjected to multi-parallel sequencing. Virus sequence diversity was calculated for each tissue. Greater diversity was seen in mosquitoes with successful dissemination versus those with no dissemination. Diversity across time revealed that bottlenecks influence diversity following dissemination to the legs/wings, but levels of diversity are restored by Day 12 post-dissemination. Specific minority variants were repeatedly identified across the mosquito cohort, some in nearly every tissue and time point, suggesting that certain variants are important in mosquito infection and dissemination. This study demonstrates that the interaction between the mosquito and the virus results in changes in diversity and the mutational spectrum and may be essential for successful transition of the bottlenecks associated with arbovirus infection.
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Affiliation(s)
- Edward I Patterson
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0610, USA
| | - Kamil Khanipov
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-0617, USA
| | - Mark M Rojas
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-0617, USA
| | - Tiffany F Kautz
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0610, USA
| | - Dedeke Rockx-Brouwer
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0610, USA
| | - Georgiy Golovko
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-0617, USA
| | - Levent Albayrak
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-0617, USA
| | - Yuriy Fofanov
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555-0617, USA
| | - Naomi L Forrester
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0610, USA
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Soong L, Mendell NL, Olano JP, Rockx-Brouwer D, Xu G, Goez-Rivillas Y, Drom C, Shelite TR, Valbuena G, Walker DH, Bouyer DH. An Intradermal Inoculation Mouse Model for Immunological Investigations of Acute Scrub Typhus and Persistent Infection. PLoS Negl Trop Dis 2016; 10:e0004884. [PMID: 27479584 PMCID: PMC4968841 DOI: 10.1371/journal.pntd.0004884] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Accepted: 07/07/2016] [Indexed: 01/08/2023] Open
Abstract
Scrub typhus is a neglected tropical disease, caused by Orientia tsutsugamushi, a Gram-negative bacterium that is transmitted to mammalian hosts during feeding by Leptotrombidium mites and replicates predominantly within endothelial cells. Most studies of scrub typhus in animal models have utilized either intraperitoneal or intravenous inoculation; however, there is limited information on infection by the natural route in murine model skin or its related early host responses. Here, we developed an intradermal (i.d.) inoculation model of scrub typhus and focused on the kinetics of the host responses in the blood and major infected organs. Following ear inoculation with 6 x 104 O. tsutsugamushi, mice developed fever at 11-12 days post-infection (dpi), followed by marked hypothermia and body weight loss at 14-19 dpi. Bacteria in blood and tissues and histopathological changes were detected around 9 dpi and peaked around 14 dpi. Serum cytokine analyses revealed a mixed Th1/Th2 response, with marked elevations of MCP-1/CCL2, MIP-1α/CCL3 and IL-10 at 9 dpi, followed by increased concentrations of pro-inflammatory markers (IL-6, IL-12, IFN-γ, G-CSF, RANTES/CCL5, KC/CCL11, IL-1α/β, IL-2, TNF-α, GM-CSF), as well as modulatory cytokines (IL-9, IL-13). Cytokine levels in lungs had similar elevation patterns, except for a marked reduction of IL-9. The Orientia 47-kDa gene and infectious bacteria were detected in several organs for up to 84 dpi, indicating persistent infection. This is the first comprehensive report of acute scrub typhus and persistent infection in i.d.-inoculated C57BL/6 mice. This is a significant improvement over current murine models for Orientia infection and will permit detailed studies of host immune responses and infection control interventions.
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Affiliation(s)
- Lynn Soong
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, School of Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Nicole L. Mendell
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, School of Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Juan P. Olano
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, School of Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Dedeke Rockx-Brouwer
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, School of Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Guang Xu
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, School of Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Yenny Goez-Rivillas
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, School of Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Claire Drom
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, School of Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Thomas R. Shelite
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Gustavo Valbuena
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, School of Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - David H. Walker
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, School of Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Donald H. Bouyer
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Center for Tropical Diseases, Sealy Center for Vaccine Development, Institute of Human Infections and Immunity, School of Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
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Smalley C, Bechelli J, Rockx-Brouwer D, Saito T, Azar SR, Ismail N, Walker DH, Fang R. Rickettsia australis Activates Inflammasome in Human and Murine Macrophages. PLoS One 2016; 11:e0157231. [PMID: 27362650 PMCID: PMC4928923 DOI: 10.1371/journal.pone.0157231] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/26/2016] [Indexed: 02/06/2023] Open
Abstract
Rickettsiae actively escape from vacuoles and replicate free in the cytoplasm of host cells, where inflammasomes survey the invading pathogens. In the present study, we investigated the interactions of Rickettsia australis with the inflammasome in both mouse and human macrophages. R. australis induced a significant level of IL-1β secretion by human macrophages, which was significantly reduced upon treatment with an inhibitor of caspase-1 compared to untreated controls, suggesting caspase-1-dependent inflammasome activation. Rickettsia induced significant secretion of IL-1β and IL-18 in vitro by infected mouse bone marrow-derived macrophages (BMMs) as early as 8-12 h post infection (p.i.) in a dose-dependent manner. Secretion of these cytokines was accompanied by cleavage of caspase-1 and was completely abrogated in BMMs deficient in caspase-1/caspase-11 or apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC), suggesting that R. australis activate the ASC-dependent inflammasome. Interestingly, in response to the same quantity of rickettsiae, NLRP3-/- BMMs significantly reduced the secretion level of IL-1β compared to wild type (WT) controls, suggesting that NLRP3 inflammasome contributes to cytosolic recognition of R. australis in vitro. Rickettsial load in spleen, but not liver and lung, of R. australis-infected NLRP3-/- mice was significantly greater compared to WT mice. These data suggest that NLRP3 inflammasome plays a role in host control of bacteria in vivo in a tissue-specific manner. Taken together, our data, for the first time, illustrate the activation of ASC-dependent inflammasome by R. australis in macrophages in which NLRP3 is involved.
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Affiliation(s)
- Claire Smalley
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Jeremy Bechelli
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Dedeke Rockx-Brouwer
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Tais Saito
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Sasha R. Azar
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Nahed Ismail
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - David H. Walker
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Rong Fang
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
- * E-mail:
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Abstract
BACKGROUND Human ehrlichioses are emerging life-threatening diseases transmitted by ticks. Animal models have been developed to study disease development; however, there is no valid small animal model that uses a human ehrlichial pathogen. The objective of this study was to develop a mouse model for ehrlichiosis with the newly discovered human pathogen, Ehrlichia muris-like agent (EMLA). METHODS Three strains of mice were inoculated with different doses of EMLA by the intravenous, intraperitoneal, or intradermal route and evaluated for clinical and pathologic changes during the course of infection. RESULTS EMLA infected C57Bl/6, BALB/c, and C3H/HeN mice and induced lethal or persistent infection in a route- and dose-dependent manner. The clinical chemistry and hematologic changes were similar to those of human infection by Ehrlichia chaffeensis or EMLA. Bacterial distribution in tissues differed after intradermal infection, compared with the distribution after intravenous or intraperitoneal injection. Lethal infection did not cause remarkable pathologic changes, but it caused fluid imbalance. EMLA infection of endothelium and mononuclear cells likely plays a role in the severe outcome. CONCLUSIONS The EMLA mouse model mimics human infection and can be used to study pathogenesis and immunity and for development of a vector transmission model of ehrlichiosis.
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Affiliation(s)
- Tais Berelli Saito
- Department of Pathology, University of Texas Medical Branch at Galveston
| | | | - Thomas R Shelite
- Department of Pathology, University of Texas Medical Branch at Galveston
| | | | - Vsevolod L Popov
- Department of Pathology, University of Texas Medical Branch at Galveston
| | - David H Walker
- Department of Pathology, University of Texas Medical Branch at Galveston
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9
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Chong A, Child R, Wehrly TD, Rockx-Brouwer D, Qin A, Mann BJ, Celli J. Structure-Function Analysis of DipA, a Francisella tularensis Virulence Factor Required for Intracellular Replication. PLoS One 2013; 8:e67965. [PMID: 23840797 PMCID: PMC3694160 DOI: 10.1371/journal.pone.0067965] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 05/23/2013] [Indexed: 12/26/2022] Open
Abstract
Francisella tularensis is a highly infectious bacterium whose virulence relies on its ability to rapidly reach the macrophage cytosol and extensively replicate in this compartment. We previously identified a novel Francisella virulence factor, DipA (FTT0369c), which is required for intramacrophage proliferation and survival, and virulence in mice. DipA is a 353 amino acid protein with a Sec-dependent signal peptide, four Sel1-like repeats (SLR), and a C-terminal coiled-coil (CC) domain. Here, we determined through biochemical and localization studies that DipA is a membrane-associated protein exposed on the surface of the prototypical F. tularensis subsp. tularensis strain SchuS4 during macrophage infection. Deletion and substitution mutagenesis showed that the CC domain, but not the SLR motifs, of DipA is required for surface exposure on SchuS4. Complementation of the dipA mutant with either DipA CC or SLR domain mutants did not restore intracellular growth of Francisella, indicating that proper localization and the SLR domains are required for DipA function. Co-immunoprecipitation studies revealed interactions with the Francisella outer membrane protein FopA, suggesting that DipA is part of a membrane-associated complex. Altogether, our findings indicate that DipA is positioned at the host–pathogen interface to influence the intracellular fate of this pathogen.
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Affiliation(s)
- Audrey Chong
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail:
| | - Robert Child
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Tara D. Wehrly
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Dedeke Rockx-Brouwer
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Aiping Qin
- Department of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
| | - Barbara J. Mann
- Department of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Jean Celli
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
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Rockx-Brouwer D, Chong A, Wehrly TD, Child R, Crane DD, Celli J, Bosio CM. Low dose vaccination with attenuated Francisella tularensis strain SchuS4 mutants protects against tularemia independent of the route of vaccination. PLoS One 2012; 7:e37752. [PMID: 22662210 PMCID: PMC3360632 DOI: 10.1371/journal.pone.0037752] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 04/24/2012] [Indexed: 01/15/2023] Open
Abstract
Tularemia, caused by the Gram-negative bacterium Francisella tularensis, is a severe, sometimes fatal disease. Interest in tularemia has increased over the last decade due to its history as a biological weapon. In particular, development of novel vaccines directed at protecting against pneumonic tularemia has been an important goal. Previous work has demonstrated that, when delivered at very high inoculums, administration of live, highly attenuated strains of virulent F. tularensis can protect against tularemia. However, lower vaccinating inoculums did not offer similar immunity. One concern of using live vaccines is that the host may develop mild tularemia in response to infection and use of high inoculums may contribute to this issue. Thus, generation of a live vaccine that can efficiently protect against tularemia when delivered in low numbers, e.g. <100 organisms, may address this concern. Herein we describe the ability of three defined, attenuated mutants of F. tularensis SchuS4, deleted for FTT0369c, FTT1676, or FTT0369c and FTT1676, respectively, to engender protective immunity against tularemia when delivered at concentrations of approximately 50 or fewer bacteria. Attenuated strains for use as vaccines were selected by their inability to efficiently replicate in macrophages in vitro and impaired replication and dissemination in vivo. Although all strains were defective for replication in vitro within macrophages, protective efficacy of each attenuated mutant was correlated with their ability to modestly replicate and disseminate in the host. Finally, we demonstrate the parenteral vaccination with these strains offered superior protection against pneumonic tularemia than intranasal vaccination. Together our data provides proof of principle that low dose attenuated vaccines may be a viable goal in development of novel vaccines directed against tularemia.
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Affiliation(s)
- Dedeke Rockx-Brouwer
- Tularemia Pathogenesis Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories National Institute of Allergy and Infectious Diseases/National Institutes of Health, Hamilton, Montana, United States of America
| | - Audrey Chong
- Tularemia Pathogenesis Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories National Institute of Allergy and Infectious Diseases/National Institutes of Health, Hamilton, Montana, United States of America
| | - Tara D. Wehrly
- Tularemia Pathogenesis Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories National Institute of Allergy and Infectious Diseases/National Institutes of Health, Hamilton, Montana, United States of America
| | - Robert Child
- Tularemia Pathogenesis Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories National Institute of Allergy and Infectious Diseases/National Institutes of Health, Hamilton, Montana, United States of America
| | - Deborah D. Crane
- Immunity to Pulmonary Pathogens Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases/National Institutes of Health, Hamilton, Montana, United States of America
| | - Jean Celli
- Tularemia Pathogenesis Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories National Institute of Allergy and Infectious Diseases/National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail: (JC); (CMB)
| | - Catharine M. Bosio
- Immunity to Pulmonary Pathogens Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases/National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail: (JC); (CMB)
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Edwards JA, Rockx-Brouwer D, Nair V, Celli J. Restricted cytosolic growth of Francisella tularensis subsp. tularensis by IFN-gamma activation of macrophages. Microbiology (Reading) 2009; 156:327-339. [PMID: 19926654 DOI: 10.1099/mic.0.031716-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The intracellular bacterium Francisella tularensis ensures its survival and proliferation within phagocytes of the infected host through phagosomal escape and cytosolic replication, to cause the disease tularemia. The cytokine interferon-gamma (IFN-gamma) is important in controlling primary infections in vivo, and in vitro intracellular proliferation of Francisella in macrophages, but its actual effects on the intracellular cycle of the bacterium are ambiguous. Here, we have performed an extensive analysis of the intracellular fate of the virulent F. tularensis subsp. tularensis strain Schu S4 in primary IFN-gamma-activated murine and human macrophages to understand how this cytokine controls Francisella proliferation. In both murine bone marrow-derived macrophages (muBMMs) and human blood monocyte-derived macrophages (MDMs), IFN-gamma controlled bacterial proliferation. Schu S4 growth inhibition was not due to a defect in phagosomal escape, since bacteria disrupted their phagosomes with indistinguishable kinetics in both muBMMs and MDMs, regardless of their activation state. Rather, IFN-gamma activation restricted cytosolic replication of Schu S4 in a manner independent of reactive oxygen or nitrogen species. Hence, IFN-gamma induces phagocyte NADPH oxidase Phox- and inducible nitric oxide synthase (iNOS)-independent cytosolic effector mechanisms that restrict growth of virulent Francisella in macrophages.
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Affiliation(s)
- Jessica A Edwards
- Tularemia Pathogenesis Section, Laboratory of Intracellular Parasites, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
| | - Dedeke Rockx-Brouwer
- Tularemia Pathogenesis Section, Laboratory of Intracellular Parasites, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
| | - Vinod Nair
- Electron Microscopy Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
| | - Jean Celli
- Tularemia Pathogenesis Section, Laboratory of Intracellular Parasites, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
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