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Hussain A, Ong EBB, Balaram P, Ismail A, Kien PK. TolC facilitates the intracellular survival and immunomodulation of Salmonella Typhi in human host cells. Virulence 2024; 15:2395831. [PMID: 39185619 PMCID: PMC11385165 DOI: 10.1080/21505594.2024.2395831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 06/29/2024] [Accepted: 08/19/2024] [Indexed: 08/27/2024] Open
Abstract
Salmonella enterica serovar Typhi (S. Typhi) causes typhoid fever, a systemic infection that affects millions of people worldwide. S. Typhi can invade and survive within host cells, such as intestinal epithelial cells and macrophages, by modulating their immune responses. However, the immunomodulatory capability of S. Typhi in relation to TolC-facilitated efflux pump function remains unclear. The role of TolC, an outer membrane protein that facilitates efflux pump function, in the invasion and immunomodulation of S. Typhi, was studied in human intestinal epithelial cells and macrophages. The tolC deletion mutant of S. Typhi was compared with the wild-type and its complemented strain in terms of their ability to invade epithelial cells, survive and induce cytotoxicity in macrophages, and elicit proinflammatory cytokine production in macrophages. The tolC mutant, which has a defective outer membrane, was impaired in invading epithelial cells compared to the wild-type strain, but the intracellular presence of the tolC mutant exhibited greater cytotoxicity and induced higher levels of proinflammatory cytokines (IL-1β and IL-8) in macrophages compared to the wild-type strain. These effects were reversed by complementing the tolC mutant with a functional tolC gene. Our results suggest that TolC plays a role in S. Typhi to efficiently invade epithelial cells and suppress host immune responses during infection. TolC may be a potential target for the development of novel therapeutics against typhoid fever.
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Affiliation(s)
- Ashraf Hussain
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL USA
| | - Eugene Boon Beng Ong
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
| | - Prabha Balaram
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
| | - Asma Ismail
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
| | - Phua Kia Kien
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Penang, Malaysia
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Wang M, Zeng J, Tan H, Guo Q, Li X, Ling X, Zhang J, Song S, Deng Y. Anti-virulence and bactericidal activities of Stattic against Shigella sonnei. Appl Environ Microbiol 2023; 89:e0107423. [PMID: 38032177 PMCID: PMC10734500 DOI: 10.1128/aem.01074-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 10/13/2023] [Indexed: 12/01/2023] Open
Abstract
IMPORTANCE Shigella sonnei is a major human enteric pathogen that causes bacillary dysentery. The increasing spread of drug-resistant S. sonnei strains has caused an emergent need for the development of new antimicrobial agents against this pathogenic bacterium. In this study, we demonstrate that Stattic employs two antibacterial mechanisms against S. sonnei. It exerted both anti-virulence activity and bactericidal activity against S. sonnei, suggesting that it shows advantages over traditional antibiotics. Moreover, Stattic showed excellent synergistic effects with kanamycin, ampicillin, chloramphenicol, and gentamicin against S. sonnei. Our findings suggest that Stattic has promising potential for development as a new antibiotic or as an adjuvant to antibiotics for infections caused by S. sonnei.
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Affiliation(s)
- Mingfang Wang
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Jia Zeng
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Huihui Tan
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Quan Guo
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Xia Li
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Xiwen Ling
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Jinyue Zhang
- School of Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Shihao Song
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
- School of Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Yinyue Deng
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
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Guo L, Dai H, Feng S, Zhao Y. Contribution of GalU to biofilm formation, motility, antibiotic and serum resistance, and pathogenicity of Salmonella Typhimurium. Front Cell Infect Microbiol 2023; 13:1149541. [PMID: 37021122 PMCID: PMC10067927 DOI: 10.3389/fcimb.2023.1149541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 03/02/2023] [Indexed: 04/07/2023] Open
Abstract
Introduction Salmonella Typhimurium is the leading cause of foodborne illnesses in China, resulting in major epidemics and economic losses in recent years. Uridine diphosphate-glucose pyrophosphorylase galU plays an important role in thebiosynthesis of the bacterial envelope. Herein, we evaluated the role of galU in S. Typhimurium infection in chicken. Methods A galU gene mutant was successfully constructed by red homologous recombination technology, and biological characteristics were studied. Results The galU mutant strain had a rough phenotype;was defective in biofilm formation, autoagglutination, and motility; exhibited greater sensitivity to most antibiotics, serum, and egg albumen; and had lowercapacity for adhesion to chicken embryo fibroblasts cell line (DF-1). The galU mutant showed dramatically attenuated pathogenicity in chicken embryos (100,000-fold), BALB/c mice (420-fold), and chicks (100-fold). Discussion The results imply that galU is an important virulence factor in the pathogenicity of S. Typhimurium, and it may serve a target for the development of veterinary drugs, providing a theoretical basis for the prevention and control of S. Typhimurium.
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Affiliation(s)
- Lili Guo
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China
| | - Huilin Dai
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Saixiang Feng
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- *Correspondence: Saixiang Feng, ; Yongda Zhao,
| | - Yongda Zhao
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China
- *Correspondence: Saixiang Feng, ; Yongda Zhao,
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Zhao X, Yang F, Wang Y, Zhang Y. hns mRNA downregulates the expression of galU and attenuates the motility of Salmonella enterica serovar Typhi. Int J Med Microbiol 2021; 311:151525. [PMID: 34340061 DOI: 10.1016/j.ijmm.2021.151525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 07/11/2021] [Accepted: 07/25/2021] [Indexed: 10/20/2022] Open
Abstract
Recently, multiple bifunctional RNAs have been discovered, which can both be translated into proteins and play regulatory roles. hns encodes the global gene silencing factor H-NS, which is widespread in Gram-negative bacteria. This study reported that hns mRNA of Salmonella enterica serovar Typhi (S. Typhi) was a bifunctional RNA that could act as an antisense RNA downregulating the expression of galU, the coding gene of uridine triphosphate-glucose-1-phosphate uridylyltransferase, and attenuating bacterial motility. galU, which is located at the opposite strand of hns, was identified to have a long 3'-untranslated region that overlapped with hns and could be processed to produce short RNA fragments. The overexpression of hns mRNA inhibited the expression of galU. The deletion of galU attenuated the motility of S. Typhi, while the complementation of galU nearly restored the phenotype. Overexpressing hns mRNA in the wild-type strain of S. Typhi inhibited the motility and the expression of flagellar genes, while overexpressing hns mRNA in the galU-deletion mutant did not influence bacterial motility. In conclusion, hns mRNA has been identified to be a new bifunctional RNA that attenuates the motility of S. Typhi by downregulating the expression of galU.
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Affiliation(s)
- Xin Zhao
- Department of Nuclear Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu, 210006, China.
| | - Fanfan Yang
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
| | - Yurou Wang
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
| | - Ying Zhang
- Department of Biochemistry and Molecular Biology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, 212013, China.
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Deletion Mutants of Francisella Phagosomal Transporters FptA and FptF Are Highly Attenuated for Virulence and Are Protective Against Lethal Intranasal Francisella LVS Challenge in a Murine Model of Respiratory Tularemia. Pathogens 2021; 10:pathogens10070799. [PMID: 34202420 PMCID: PMC8308642 DOI: 10.3390/pathogens10070799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/09/2021] [Accepted: 06/17/2021] [Indexed: 11/17/2022] Open
Abstract
Francisella tularensis (Ft) is a Gram-negative, facultative intracellular bacterium that is a Tier 1 Select Agent of concern for biodefense for which there is no licensed vaccine. A subfamily of 9 Francisella phagosomal transporter (fpt) genes belonging to the Major Facilitator Superfamily of transporters was identified as critical to pathogenesis and potential targets for attenuation and vaccine development. We evaluated the attenuation and protective capacity of LVS derivatives with deletions of the fptA and fptF genes in the C57BL/6J mouse model of respiratory tularemia. LVSΔfptA and LVSΔfptF were highly attenuated with LD50 values of >20 times that of LVS when administered intranasally and conferred 100% protection against lethal challenge. Immune responses to the fpt mutant strains in mouse lungs on day 6 post-infection were substantially modified compared to LVS and were associated with reduced organ burdens and reduced pathology. The immune responses to LVSΔfptA and LVSΔfptF were characterized by decreased levels of IL-10 and IL-1β in the BALF versus LVS, and increased numbers of B cells, αβ and γδ T cells, NK cells, and DCs versus LVS. These results support a fundamental requirement for FptA and FptF in the pathogenesis of Ft and the modulation of the host immune response.
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Cytosolic Gram-negative bacteria prevent apoptosis by inhibition of effector caspases through lipopolysaccharide. Nat Microbiol 2019; 5:354-367. [PMID: 31873204 DOI: 10.1038/s41564-019-0620-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 10/24/2019] [Indexed: 02/08/2023]
Abstract
The cytosolic appearance and propagation of bacteria cause overwhelming cellular stress responses that induce apoptosis under normal conditions. Therefore, successful bacterial colonization depends on the ability of intracellular pathogens to block apoptosis and to safeguard bacterial replicative niches. Here, we show that the cytosolic Gram-negative bacterium Shigella flexneri stalls apoptosis by inhibiting effector caspase activity. Our data identified lipopolysaccharide (LPS) as a bona fide effector caspase inhibitor that directly binds caspases by involving its O-antigen (O Ag) moiety. Bacterial strains that lacked the O Ag or failed to replicate within the cytosol were incapable of blocking apoptosis and exhibited reduced virulence in a murine model of bacterial infection. Our findings demonstrate how Shigella inhibits pro-apoptotic caspase activity, effectively delays coordinated host-cell demise and supports its intracellular propagation. Next to the recently discovered pro-inflammatory role of cytosolic LPS, our data reveal a distinct mode of LPS action that, through the disruption of the early coordinated non-lytic cell death response, ultimately supports the inflammatory breakdown of infected cells at later time points.
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Screen for fitness and virulence factors of Francisella sp. strain W12-1067 using amoebae. Int J Med Microbiol 2019; 309:151341. [PMID: 31451389 DOI: 10.1016/j.ijmm.2019.151341] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/17/2019] [Accepted: 08/18/2019] [Indexed: 11/21/2022] Open
Abstract
Francisella tularensis is the causative agent of the human disease referred to as tularemia. Other Francisella species are known but less is understood about their virulence factors. The role of environmental amoebae in the life-cycle of Francisella is still under discussion. Francisella sp. strain W12-1067 (F-W12) is an environmental Francisella isolate recently identified in Germany which is negative for the Francisella pathogenicity island, but exhibits a putative alternative type VI secretion system. Putative virulence factors have been identified in silico in the genome of F-W12. In this work, we established a "scatter screen", used earlier for pathogenic Legionella, to verify experimentally and identify candidate fitness factors using a transposon mutant bank of F-W12 and Acanthamoeba lenticulata as host organism. In these experiments, we identified 79 scatter clones (amoeba sensitive), which were further analyzed by an infection assay identifying 9 known virulence factors, but also candidate fitness factors of F-W12 not yet described as fitness factors in Francisella. The majority of the identified genes encoded proteins involved in the synthesis or maintenance of the cell envelope (LPS, outer membrane, capsule) or in the metabolism (glycolysis, gluconeogenesis, pentose phosphate pathway). Further 13C-flux analysis of the Tn5 glucokinase mutant strain revealed that the identified gene indeed encodes the sole active glucokinase in F-W12. In conclusion, candidate fitness factors of the new Francisella species F-W12 were identified using the scatter screen method which might also be usable for other Francisella species.
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Abstract
BACKGROUND Campylobacter species are a leading cause of bacterial foodborne illness worldwide. Despite the global efforts to curb them, Campylobacter infections have increased continuously in both developed and developing countries. The development of effective strategies to control the infection by this pathogen is warranted. The essential genes of bacteria are the most prominent targets for this purpose. In this study, we used transposon sequencing (Tn-seq) of a genome-saturating library of Tn5 insertion mutants to define the essential genome of C. jejuni at a high resolution. RESULT We constructed a Tn5 mutant library of unprecedented complexity in C. jejuni NCTC 11168 with 95,929 unique insertions throughout the genome and used the genomic DNA of the library for the reconstruction of Tn5 libraries in the same (C. jejuni NCTC 11168) and different strain background (C. jejuni 81-176) through natural transformation. We identified 166 essential protein-coding genes and 20 essential transfer RNAs (tRNA) in C. jejuni NCTC 11168 which were intolerant to Tn5 insertions during in vitro growth. The reconstructed C. jejuni 81-176 library had 384 protein coding genes with no Tn5 insertions. Essential genes in both strain backgrounds were highly enriched in the cluster of orthologous group (COG) categories of 'Translation, ribosomal structure and biogenesis (J)', 'Energy production and conversion (C)', and 'Coenzyme transport and metabolism (H)'. CONCLUSION Comparative analysis among this and previous studies identified 50 core essential genes of C. jejuni, which can be further investigated for the development of novel strategies to control the spread of this notorious foodborne bacterial pathogen.
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Affiliation(s)
- Rabindra K. Mandal
- Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701 USA
- Present Address: Department of Microbiology and Immunology, Clinical Translational Research Building, University of Louisville, Louisville, KY 40202 USA
| | - Tieshan Jiang
- Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701 USA
| | - Young Min Kwon
- Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701 USA
- Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701 USA
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Zavala A, Kovacec V, Levín G, Moglioni A, Miranda MV, García E, Bonofiglio L, Mollerach M. Screening assay for inhibitors of a recombinant Streptococcus pneumoniae UDP-glucose pyrophosphorylase. J Enzyme Inhib Med Chem 2017; 32:203-207. [PMID: 28114831 PMCID: PMC6009895 DOI: 10.1080/14756366.2016.1247055] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The UDP-glucose pyrophosphorylase of Streptococcus pneumoniae (GalUSpn) is absolutely required for the biosynthesis of capsular polysaccharide, the sine qua non virulence factor of pneumococcus. Since the eukaryotic enzymes are completely unrelated to their prokaryotic counterparts, we propose that the GalU enzyme is a critical target to fight the pneumococcal disease. A recombinant GalUSpn was overexpressed and purified. An enzymatic assay that is rapid, sensitive and easy to perform was developed. This assay was appropriate for screening chemical libraries for searching GalU inhibitors. This work represents a fundamental step in the exploration of novel antipneumococcal drugs.
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Affiliation(s)
- Agustín Zavala
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
| | - Verónica Kovacec
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
| | - Gustavo Levín
- b Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Biotecnología , Buenos Aires , Argentina
| | - Albertina Moglioni
- c Departamento de Farmacología, Facultad de Farmacia y Bioquímica , Cátedra de Química Medicinal, Universidad de Buenos Aires , Buenos Aires , Argentina
| | - María Victoria Miranda
- b Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Biotecnología , Buenos Aires , Argentina
| | - Ernesto García
- d Centro de Investigaciones Biológicas, CSIC and CIBER de Enfermedades Respiratorias (CIBERES) , Madrid , Spain
| | - Laura Bonofiglio
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
| | - Marta Mollerach
- a Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Microbiología , Inmunología y Biotecnología, Cátedra de Microbiología , Buenos Aires , Argentina
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Abstract
Francisella tularensis is a facultative intracellular bacterium causing tularemia, a zoonotic disease. Francisella replicates in the macrophage cytosol and eventually triggers cytosolic immune responses. In murine macrophages, Francisella novicida and Francisella tularensis live vaccine strain lyse in the host cytosol and activate the cytosolic DNA receptor Aim2. Here, we review the mechanisms leading or contributing to Aim2 inflammasome activation, including the role of TLRs and of IFN signaling and the implication of the guanylate-binding proteins 2 and 5 in triggering cytosolic bacteriolysis. Furthermore, we present how this cytosolic Gram-negative bacterium escapes recognition by caspase-11 but can trigger a non-canonical caspase-8 inflammasome. In addition, we highlight the differences in inflammasome activation in murine and human cells with pyrin, NLRP3, and AIM2 involved in sensing Francisella in human phagocytes. From a bacterial prospective, we describe the hiding strategy of Francisella to escape recognition by innate sensors and to resist to bacteriolysis in the host cytosol. Finally, we discuss the inability of the inflammasome sensors to detect F. tularensis subspecies tularensis strains, making them highly pathogenic stealth microbes.
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Yogiara, Kim D, Hwang JK, Pan JG. Escherichia coli ASKA Clone Library Harboring tRNA-Specific Adenosine Deaminase (tadA) Reveals Resistance towards Xanthorrhizol. Molecules 2015; 20:16290-305. [PMID: 26370953 PMCID: PMC6331797 DOI: 10.3390/molecules200916290] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/27/2015] [Accepted: 08/31/2015] [Indexed: 11/16/2022] Open
Abstract
Xanthorrhizol is a potent antimicrobial compound isolated from the rhizome of Curcuma xanthorrhiza. However, the mechanism of xanthorrhizol action is unknown. To screen for probable target(s), we introduced the ASKA pooled-plasmid library into Escherichia coli W3110 imp4213 and enriched the library for resistant clones with increasing concentrations of xanthorrhizol. After three rounds of enrichment, we found nine genes that increased xanthorrhizol resistance. The resistant clones were able to grow in LB medium containing 256 µg/mL xanthorrhizol, representing a 16-fold increase in the minimum inhibitory concentration. Subsequent DNA sequence analysis revealed that overexpression of tadA, galU, fucU, ydeA, ydaC, soxS, nrdH, yiiD, and mltF genes conferred increased resistance towards xanthorrhizol. Among these nine genes, tadA is the only essential gene. tadA encodes a tRNA-specific adenosine deaminase. Overexpression of E. coli W3110 imp4213 (pCA24N-tadA) conferred resistance to xanthorrhizol up to 128 µg/mL. Moreover, overexpression of two tadA mutant enzymes (A143V and F149G) led to a twofold increase in the MIC. These results suggest that the targets of xanthorrhizol may include tadA, which has never before been explored as an antibiotic target.
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Affiliation(s)
- Yogiara
- Department of Biotechnology, Yonsei University, 50-Yonsei-ro Seodaemun-gu, Seoul 120-749, Korea.
- Faculty of Biotechnology, Atma Jaya Catholic University of Indonesia, Jalan Jenderal Sudirman 51, Jakarta 12930, Indonesia.
| | - Dooil Kim
- Superbacteria Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 111 Gwahangno, Yuseong, Daejeon 305-806, Korea.
| | - Jae-Kwan Hwang
- Department of Biotechnology, Yonsei University, 50-Yonsei-ro Seodaemun-gu, Seoul 120-749, Korea.
| | - Jae-Gu Pan
- Superbacteria Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 111 Gwahangno, Yuseong, Daejeon 305-806, Korea.
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Méndez JA, Mateos J, Beceiro A, Lopez M, Tomás M, Poza M, Bou G. Quantitative proteomic analysis of host--pathogen interactions: a study of Acinetobacter baumannii responses to host airways. BMC Genomics 2015; 16:422. [PMID: 26025090 PMCID: PMC4449591 DOI: 10.1186/s12864-015-1608-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 05/01/2015] [Indexed: 01/23/2023] Open
Abstract
Background Acinetobacter baumannii is a major health problem. The most common infection caused by A. baumannii is hospital acquired pneumonia, and the associated mortality rate is approximately 50 %. Neither in vivo nor ex vivo expression profiling has been performed at the proteomic or transcriptomic level for pneumonia caused by A. baumannii. In this study, we characterized the proteome of A. baumannii under conditions that simulate those found in the airways, to gain some insight into how A. baumannii adapts to the host and to improve knowledge about the pathogenesis and virulence of this bacterium. A clinical strain of A. baumannii was grown under different conditions: in the presence of bronchoalveolar lavage fluid from infected rats, of RAW 264.7 cells to simulate conditions in the respiratory tract and in control conditions. We used iTRAQ labelling and LC-MALDI-TOF/TOF to investigate how A. baumannii responds on exposure to macrophages/BALF. Results 179 proteins showed differential expression. In both models, proteins involved in the following processes were over-expressed: (i) pathogenesis and virulence (OmpA, YjjK); (ii) cell wall/membrane/envelope biogenesis (MurC); (iii) energy production and conversion (acetyl-CoA hydrolase); and (iv) translation (50S ribosomal protein L9). Proteins involved in the following were under-expressed: (i) lipid metabolism (short-chain dehydrogenase); (ii) amino acid metabolism and transport (aspartate aminotransferase); (iii) unknown function (DNA-binding protein); and (iv) inorganic ion transport and metabolism (hydroperoxidase). Conclusions We observed alterations in cell wall synthesis and identified 2 upregulated virulence-associated proteins with >15 peptides/protein in both ex vivo models (OmpA and YjjK), suggesting that these proteins are fundamental for pathogenesis and virulence in the airways. This study is the first comprehensive overview of the ex vivo proteome of A. baumannii and is an important step towards identification of diagnostic biomarkers, novel drug targets and potential vaccine candidates in the fight against pneumonia caused by A. baumannii. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1608-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jose Antonio Méndez
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - Jesús Mateos
- Grupo de Proteomica-PBR2-ProteoRed/ISCIII-Servicio de Reumatologia, A Coruña, Spain.
| | - Alejandro Beceiro
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - María Lopez
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - María Tomás
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - Margarita Poza
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
| | - Germán Bou
- Microbiology Division, INIBIC-Complejo Hospitalario Universitario de la Coruña, A Coruña, Spain.
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del Barrio L, Sahoo M, Lantier L, Reynolds JM, Ceballos-Olvera I, Re F. Production of anti-LPS IgM by B1a B cells depends on IL-1β and is protective against lung infection with Francisella tularensis LVS. PLoS Pathog 2015; 11:e1004706. [PMID: 25768794 PMCID: PMC4358995 DOI: 10.1371/journal.ppat.1004706] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 01/26/2015] [Indexed: 01/28/2023] Open
Abstract
The role of IL-1β and IL-18 during lung infection with the gram-negative bacterium Francisella tularensis LVS has not been characterized in detail. Here, using a mouse model of pneumonic tularemia, we show that both cytokines are protective, but through different mechanisms. Il-18-/- mice quickly succumb to the infection and showed higher bacterial burden in organs and lower level of IFNγ in BALF and serum compared to wild type C57BL/6J mice. Administration of IFNγ rescued the survival of Il-18-/- mice, suggesting that their decreased resistance to tularemia is due to inability to produce IFNγ. In contrast, mice lacking IL-1 receptor or IL-1β, but not IL-1α, appeared to control the infection in its early stages, but eventually succumbed. IFNγ administration had no effect on Il-1r1-/- mice survival. Rather, Il-1r1-/- mice were found to have significantly reduced titer of Ft LPS-specific IgM. The anti-Ft LPS IgM was generated in a IL-1β-, TLR2-, and ASC-dependent fashion, promoted bacteria agglutination and phagocytosis, and was protective in passive immunization experiments. B1a B cells produced the anti-Ft LPS IgM and these cells were significantly decreased in the spleen and peritoneal cavity of infected Il-1b-/- mice, compared to C57BL/6J mice. Collectively, our results show that IL-1β and IL-18 activate non-redundant protective responses against tularemia and identify an essential role for IL-1β in the rapid generation of pathogen-specific IgM by B1a B cells.
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Affiliation(s)
- Laura del Barrio
- Department of Microbiology & Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Manoranjan Sahoo
- Department of Microbiology & Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Louis Lantier
- Department of Microbiology & Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Joseph M. Reynolds
- Department of Microbiology & Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Ivonne Ceballos-Olvera
- Department of Microbiology & Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
| | - Fabio Re
- Department of Microbiology & Immunology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, United States of America
- * E-mail:
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14
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Ulland TK, Ferguson PJ, Sutterwala FS. Evasion of inflammasome activation by microbial pathogens. J Clin Invest 2015; 125:469-77. [PMID: 25642707 DOI: 10.1172/jci75254] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Activation of the inflammasome occurs in response to infection with a wide array of pathogenic microbes. The inflammasome serves as a platform to activate caspase-1, which results in the subsequent processing and secretion of the proinflammatory cytokines IL-1β and IL-18 and the initiation of an inflammatory cell death pathway termed pyroptosis. Effective inflammasome activation is essential in controlling pathogen replication as well as initiating adaptive immune responses against the offending pathogens. However, a number of pathogens have developed strategies to evade inflammasome activation. In this Review, we discuss these pathogen evasion strategies as well as the potential infectious complications of therapeutic blockade of IL-1 pathways.
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15
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TolC-dependent modulation of host cell death by the Francisella tularensis live vaccine strain. Infect Immun 2014; 82:2068-78. [PMID: 24614652 DOI: 10.1128/iai.00044-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Francisella tularensis is a facultative intracellular, Gram-negative pathogen and the causative agent of tularemia. We previously identified TolC as a virulence factor of the F. tularensis live vaccine strain (LVS) and demonstrated that a ΔtolC mutant exhibits increased cytotoxicity toward host cells and elicits increased proinflammatory responses compared to those of the wild-type (WT) strain. TolC is the outer membrane channel component used by the type I secretion pathway to export toxins and other bacterial virulence factors. Here, we show that the LVS delays activation of the intrinsic apoptotic pathway in a TolC-dependent manner, both during infection of primary macrophages and during organ colonization in mice. The TolC-dependent delay in host cell death is required for F. tularensis to preserve its intracellular replicative niche. We demonstrate that TolC-mediated inhibition of apoptosis is an active process and not due to defects in the structural integrity of the ΔtolC mutant. These findings support a model wherein the immunomodulatory capacity of F. tularensis relies, at least in part, on TolC-secreted effectors. Finally, mice vaccinated with the ΔtolC LVS are protected from lethal challenge and clear challenge doses faster than WT-vaccinated mice, demonstrating that the altered host responses to primary infection with the ΔtolC mutant led to altered adaptive immune responses. Taken together, our data demonstrate that TolC is required for temporal modulation of host cell death during infection by F. tularensis and highlight how shifts in the magnitude and timing of host innate immune responses may lead to dramatic changes in the outcome of infection.
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Emery FD, Stabenow JM, Miller MA. Efficient inactivation of Burkholderia pseudomallei or Francisella tularensis in infected cells for safe removal from biosafety level 3 containment laboratories. Pathog Dis 2014; 71:276-81. [PMID: 24449562 DOI: 10.1111/2049-632x.12138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/10/2013] [Accepted: 01/06/2014] [Indexed: 12/30/2022] Open
Abstract
Working with infectious agents that require BSL-3 level containment agents offers many challenges for researchers. BSL-3 containment laboratories are usually not equipped with expensive specialty equipment that is needed for studies such as flow cytometric analysis, microscopy, and proteomic analyses. Therefore, for most researchers that are working with BSL-3 level infectious agents, removal of samples from BSL-3 laboratories for these types of studies is necessary, and methods for complete and dependable inactivation of the samples are required. In this report, we have carried out a thorough characterization of the effectiveness of paraformaldehyde fixation for inactivation of cell samples infected with the intracellular bacterial agents Burkholderia pseudomallei (Bp) and Francisella tularensis (Ft), both of which are Tier 1 select agent pathogens that require BSL-3 containment. We have demonstrated that cells infected with these pathogens are completely inactivated via 5-min treatment with 4% paraformaldehyde. Moreover, a 15-min treatment with 2% paraformaldehyde completely sterilized both Bp- and Ft-infected cells. These studies also revealed that Bp is significantly more sensitive to paraformaldehyde treatment than Ft. Our findings have clearly demonstrated that a 15-min treatment of Bp- or Ft-infected cells with 4% paraformaldehyde solution will allow for safe removal of the cell samples from BSL-3 laboratories for downstream studies.
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Affiliation(s)
- Felicia D Emery
- The University of Tennessee Health Science Center, Memphis, TN, USA
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Kawano Y, Sekine M, Ihara M. Identification and characterization of UDP-glucose pyrophosphorylase in cyanobacteria Anabaena sp. PCC 7120. J Biosci Bioeng 2013; 117:531-8. [PMID: 24231376 DOI: 10.1016/j.jbiosc.2013.10.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 10/15/2013] [Accepted: 10/17/2013] [Indexed: 10/26/2022]
Abstract
Exopolysaccharides produced by photosynthetic cyanobacteria have received considerable attention in recent years for their potential applications in the production of renewable biofuels. Particularly, cyanobacterial cellulose is one of the most promising products because it is extracellularly secreted as a non-crystalline form, which can be easily harvested from the media and converted into glucose units. In cyanobacteria, the production of UDP-glucose, the cellulose precursor, is a key step in the cellulose synthesis pathway. UDP-glucose is synthesized from UTP and glucose-1-phosphate (Glc-1P) by UDP-glucose pyrophosphorylase (UGPase), but this pathway in cyanobacteria has not been well characterized. Therefore, to elucidate the overall cellulose biosynthesis pathway in cyanobacteria, we studied the putative UGPase All3274 and seven other putative NDP-sugar pyrophosphorylases (NSPases), All4645, Alr2825, Alr4491, Alr0188, Alr3400, Alr2361, and Alr3921 of Anabaena sp. PCC 7120. Assays using the purified recombinant proteins revealed that All3274 exhibited UGPase activity, All4645, Alr2825, Alr4491, Alr0188, and Alr3921 exhibited pyrophosphorylase activities on ADP-glucose, CDP-glucose, dTDP-glucose, GDP-mannose, and UDP-N-acetylglucosamine, respectively. Further characterization of All3274 revealed that the kcat for UDP-glucose formation was one or two orders lower than those of other known UGPases. The activity and dimerization tendency of All3274 increased at higher enzyme concentrations, implying catalytic activation by dimerization. However, most interestingly, All3274 dimerization was inhibited by UTP and Glc-1P, but not by UDP-glucose. This study presents the first in vitro characterization of a cyanobacterial UGPase, and provides insights into biotechnological attempts to utilize the photosynthetic production of cellulose from cyanobacteria.
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Affiliation(s)
- Yusuke Kawano
- Faculty of Agriculture, Shinshu University, 8304 Minamiminowa, Nagano 399-4511, Japan; Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Midori Sekine
- Faculty of Agriculture, Shinshu University, 8304 Minamiminowa, Nagano 399-4511, Japan
| | - Masaki Ihara
- Faculty of Agriculture, Shinshu University, 8304 Minamiminowa, Nagano 399-4511, Japan; JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
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Abstract
Francisella tularensis is a highly virulent bacterial pathogen that is easily aerosolized and has a low infectious dose. As an intracellular pathogen, entry of Francisella into host cells is critical for its survival and virulence. However, the initial steps of attachment and internalization of Francisella into host cells are not well characterized, and little is known about bacterial factors that promote these processes. This review highlights our current understanding of Francisella attachment and internalization into host cells. In particular, we emphasize the host cell types Francisella has been shown to interact with, as well as specific receptors and signaling processes involved in the internalization process. This review will shed light on gaps in our current understanding and future areas of investigation.
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Affiliation(s)
- G Brett Moreau
- Department of Microbiology, Immunology, and Cancer Biology; University of Virginia; Charlottesville, VA USA
| | - Barbara J Mann
- Department of Microbiology, Immunology, and Cancer Biology; University of Virginia; Charlottesville, VA USA; Department of Medicine; Division of Infectious Diseases and International Health; University of Virginia; Charlottesville, VA USA
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Live attenuated tularemia vaccines: recent developments and future goals. Vaccine 2013; 31:3485-91. [PMID: 23764535 DOI: 10.1016/j.vaccine.2013.05.096] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 05/20/2013] [Accepted: 05/24/2013] [Indexed: 12/24/2022]
Abstract
In the aftermath of the 2001 anthrax attacks in the U.S., numerous efforts were made to increase the level of preparedness against a biological attack both in the US and worldwide. As a result, there has been an increase in research interest in the development of vaccines and other countermeasures against a number of agents with the potential to be used as biological weapons. One such agent, Francisella tularensis, has been the subject of a surge in the level of research being performed, leading to a substantial increase in knowledge of the pathogenic mechanisms of the organism and the induced immune responses. This information has facilitated the development of multiple new Francisella vaccine candidates. Herein we review the latest live attenuated F. tularensis vaccine efforts. Historically, live attenuated vaccines have demonstrated the greatest degree of success in protection against tularemia and the greatest promise in recent efforts to develop of a fully protective vaccine. This review summarizes recent live attenuated Francisella vaccine candidates and the lessons learned from those studies, with the goal of collating known characteristics associated with successful attenuation, immunogenicity, and protection.
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The role of galU and galE of Haemophilus parasuis SC096 in serum resistance and biofilm formation. Vet Microbiol 2013; 162:278-84. [DOI: 10.1016/j.vetmic.2012.08.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 08/08/2012] [Accepted: 08/10/2012] [Indexed: 11/20/2022]
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Racz R, Chung M, Xiang Z, He Y. Systematic annotation and analysis of "virmugens"-virulence factors whose mutants can be used as live attenuated vaccines. Vaccine 2012; 31:797-805. [PMID: 23219434 DOI: 10.1016/j.vaccine.2012.11.066] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/22/2012] [Accepted: 11/25/2012] [Indexed: 12/30/2022]
Abstract
Live attenuated vaccines are usually generated by mutation of genes encoding virulence factors. "Virmugen" is coined here to represent a gene that encodes for a virulent factor of a pathogen and has been proven feasible in animal models to make a live attenuated vaccine by knocking out this gene. Not all virulence factors are virmugens. VirmugenDB is a web-based virmugen database (http://www.violinet.org/virmugendb). Currently, VirmugenDB includes 225 virmugens that have been verified to be valuable for vaccine development against 57 bacterial, viral, and protozoan pathogens. Bioinformatics analysis has revealed significant patterns in virmugens. For example, 10 Gram-negative and 1 Gram-positive bacterial aroA genes are virmugens. A sequence analysis has revealed at least 50% of identities in the protein sequences of the 10 Gram-negative bacterial aroA virmugens. As a pathogen case study, Brucella virmugens were analyzed. Out of 15 verified Brucella virmugens, 6 are related to carbohydrate or nucleotide transport and metabolism, and 2 involving cell membrane biogenesis. In addition, 54 virmugens from 24 viruses and 12 virmugens from 4 parasites are also stored in VirmugenDB. Virmugens tend to involve metabolism of nutrients (e.g., amino acids, carbohydrates, and nucleotides) and cell membrane formation. Host genes whose expressions were regulated by virmugen mutation vaccines or wild type virulent pathogens have also been annotated and systematically compared. The bioinformatics annotation and analysis of virmugens helps to elucidate enriched virmugen profiles and the mechanisms of protective immunity, and further supports rational vaccine design.
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Affiliation(s)
- Rebecca Racz
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI 48109, USA
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Francisella tularensis live vaccine strain folate metabolism and pseudouridine synthase gene mutants modulate macrophage caspase-1 activation. Infect Immun 2012; 81:201-8. [PMID: 23115038 DOI: 10.1128/iai.00991-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Francisella tularensis is a Gram-negative bacterium and the causative agent of the disease tularemia. Escape of F. tularensis from the phagosome into the cytosol of the macrophage triggers the activation of the AIM2 inflammasome through a mechanism that is not well understood. Activation of the AIM2 inflammasome results in autocatalytic cleavage of caspase-1, resulting in the processing and secretion of interleukin-1β (IL-1β) and IL-18, which play a crucial role in innate immune responses to F. tularensis. We have identified the 5-formyltetrahydrofolate cycloligase gene (FTL_0724) as being important for F. tularensis live vaccine strain (LVS) virulence. Infection of mice in vivo with a F. tularensis LVS FTL_0724 mutant resulted in diminished mortality compared to infection of mice with wild-type LVS. The FTL_0724 mutant also induced increased inflammasome-dependent IL-1β and IL-18 secretion and cytotoxicity in macrophages in vitro. In contrast, infection of macrophages with a F. tularensis LVS rluD pseudouridine synthase (FTL_0699) mutant resulted in diminished IL-1β and IL-18 secretion from macrophages in vitro compared to infection of macrophages with wild-type LVS. In addition, the FTL_0699 mutant was not attenuated in vivo. These findings further illustrate that F. tularensis LVS possesses numerous genes that influence its ability to activate the inflammasome, which is a key host strategy to control infection with this pathogen in vivo.
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Members of the Francisella tularensis phagosomal transporter subfamily of major facilitator superfamily transporters are critical for pathogenesis. Infect Immun 2012; 80:2390-401. [PMID: 22508856 DOI: 10.1128/iai.00144-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Francisella tularensis is the causative agent of tularemia. Due to its aerosolizable nature and low infectious dose, F. tularensis is classified as a category A select agent and, therefore, is a priority for vaccine development. Survival and replication in macrophages and other cell types are critical to F. tularensis pathogenesis, and impaired intracellular survival has been linked to a reduction in virulence. The F. tularensis genome is predicted to encode 31 major facilitator superfamily (MFS) transporters, and the nine-member Francisella phagosomal transporter (Fpt) subfamily possesses homology with virulence factors in other intracellular pathogens. We hypothesized that these MFS transporters may play an important role in F. tularensis pathogenesis and serve as good targets for attenuation and vaccine development. Here we show altered intracellular replication kinetics and attenuation of virulence in mice infected with three of the nine Fpt mutant strains compared with wild-type (WT) F. tularensis LVS. The vaccination of mice with these mutant strains was protective against a lethal intraperitoneal challenge. Additionally, we observed pronounced differences in cytokine profiles in the livers of mutant-infected mice, suggesting that alterations in in vivo cytokine responses are a major contributor to the attenuation observed for these mutant strains. These results confirm that this subset of MFS transporters plays an important role in the pathogenesis of F. tularensis and suggest that a focus on the development of attenuated Fpt subfamily MFS transporter mutants is a viable strategy toward the development of an efficacious vaccine.
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