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Xu L, Li J, Wu W, Wu X, Ren J. Klebsiella pneumoniae capsular polysaccharide: Mechanism in regulation of synthesis, virulence, and pathogenicity. Virulence 2024; 15:2439509. [PMID: 39668724 PMCID: PMC11649230 DOI: 10.1080/21505594.2024.2439509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Revised: 09/04/2024] [Accepted: 12/03/2024] [Indexed: 12/14/2024] Open
Abstract
Hypervirulent Klebsiella pneumoniae exhibits strong pathogenicity and can cause severe invasive infections but is historically recognized as antibiotic-susceptible. In recent years, the escalating global prevalence of antibiotic-resistant hypervirulent K. pneumoniae has raised substantial concerns and created an urgent demand for effective treatment options. Capsular polysaccharide (CPS) is one of the main virulence determinants contributing to the hypervirulent phenotype. The structure of CPS varies widely among strains, and both the structure and composition of CPS can influence the virulence of K. pneumoniae. CPS possesses various immune evasion mechanisms that promote the survival of K. pneumoniae, as well as its colonization and dissemination. Given the proven viability of therapies that target the capsule, improving our understanding of the CPS structure is critical to effectively directing treatment strategies. In this review, the structure and typing of CPS are addressed as well as genes related to synthesis and regulation, relationships with virulence, and pathogenic mechanisms. We aim to provide a reference for research on the pathogenesis of K. pneumoniae.
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Affiliation(s)
- Li Xu
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing Medical University, Nanjing, China
| | - Jiayang Li
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Wenqi Wu
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Xiuwen Wu
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing Medical University, Nanjing, China
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Jianan Ren
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing Medical University, Nanjing, China
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
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A Regulatory SRNA Rli43 Is Involved in the Modulation of Biofilm Formation and Virulence in Listeria monocytogenes. Pathogens 2022; 11:pathogens11101137. [PMID: 36297193 PMCID: PMC9606912 DOI: 10.3390/pathogens11101137] [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: 07/23/2022] [Revised: 09/11/2022] [Accepted: 09/28/2022] [Indexed: 11/24/2022] Open
Abstract
Small RNAs (sRNAs) are a kind of regulatory molecule that can modulate gene expression at the post-transcriptional level, thereby involving alteration of the physiological characteristics of bacteria. However, the regulatory roles and mechanisms of most sRNAs remain unknown in Listeria monocytogenes(L. monocytogenes). To explore the regulatory roles of sRNA Rli43 in L. monocytogenes, the rli43 gene deletion strain LM-Δrli43 and complementation strain LM-Δrli43-rli43 were constructed to investigate the effects of Rli43 on responses to environmental stress, biofilm formation, and virulence, respectively. Additionally, Rli43-regulated target genes were identified using bioinformatic analysis tools and a bacterial dual plasmid reporter system based on E. coli. The results showed that the intracellular expression level of the rli43 gene was significantly upregulated compared with those under extracellular conditions. Compared with the parental and complementation strains, the environmental adaptation, motility, biofilm formation, adhesion, invasion, and intracellular survival of LM-Δrli43 were significantly reduced, respectively, whereas the LD50 of LM-Δrli43 was significantly elevated in BALB/c mice. Furthermore, the bacterial loads and pathological damages were alleviated, suggesting that sRNA Rli43 was involved in the modulation of the virulence of L. monocytogenes. It was confirmed that Rli43 may complementarily pair with the 5'-UTR (-47--55) of HtrA mRNA, thereby regulating the expression level of HtrA protein at the post-transcriptional level. These findings suggest that Rli43-mediated control was involved in the modulation of environmental adaptation, biofilm formation, and virulence in L. monocytogenes.
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Cao Q, Wei W, Wang H, Wang Z, Lv Y, Dai M, Tan C, Chen H, Wang X. Cleavage of E-cadherin by porcine respiratory bacterial pathogens facilitates airway epithelial barrier disruption and bacterial paracellular transmigration. Virulence 2021; 12:2296-2313. [PMID: 34482810 PMCID: PMC8425755 DOI: 10.1080/21505594.2021.1966996] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Airway epithelial cells are the first line of defense against respiratory pathogens. Porcine bacterial pathogens, such as Bordetella bronchiseptica, Actinobacillus pleuropneumoniae, Glaesserella (Haemophilus) parasuis, and Pasteurella multocida, breach this barrier to lead to local or systematic infections. Here, we demonstrated that respiratory bacterial pathogen infection disrupted the airway epithelial intercellular junction protein, E-cadherin, thus contributing to impaired epithelial cell integrity. E-cadherin knocking-out in newborn pig tracheal cells via CRISPR/Cas9 editing technology confirmed that E-cadherin was sufficient to suppress the paracellular transmigration of these porcine respiratory bacterial pathogens, including G. parasuis, A. pleuropneumoniae, P. multocida, and B. bronchiseptica. The E-cadherin ectodomain cleavage by these pathogens was probably attributed to bacterial HtrA/DegQ protease, but not host HtrA1, MMP7 and ADAM10, and the prominent proteolytic activity was further confirmed by a serine-to-alanine substitution mutation in the active center of HtrA/DegQ protein. Moreover, deletion of the htrA gene in G. parasuis led to severe defects in E-cadherin ectodomain cleavage, cell adherence and paracellular transmigration in vitro, as well as bacterial breaking through the tracheal epithelial cells, systemic invasion and dissemination in vivo. This common pathogenic mechanism shared by other porcine respiratory bacterial pathogens explains how these bacterial pathogens destroy the airway epithelial cell barriers and proliferate in respiratory mucosal surface or other systemic tissues.
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Affiliation(s)
- Qi Cao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Wenbin Wei
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Huan Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Zesong Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Yujin Lv
- College of Veterinary Medicine, Henan University of Animal Husbandry and Economy, Zhengzhou, Henan, China
| | - Menghong Dai
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China
| | - Chen Tan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China.,Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture of the People's Republic of China, Wuhan, Hubei, China.,International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China, Wuhan, Hubei, China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China.,Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture of the People's Republic of China, Wuhan, Hubei, China.,International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China, Wuhan, Hubei, China
| | - Xiangru Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, Hubei, China.,Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture of the People's Republic of China, Wuhan, Hubei, China.,International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China, Wuhan, Hubei, China
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From Klebsiella pneumoniae Colonization to Dissemination: An Overview of Studies Implementing Murine Models. Microorganisms 2021; 9:microorganisms9061282. [PMID: 34204632 PMCID: PMC8231111 DOI: 10.3390/microorganisms9061282] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 12/31/2022] Open
Abstract
Klebsiella pneumoniae is a Gram-negative pathogen responsible for community-acquired and nosocomial infections. The strains of this species belong to the opportunistic group, which is comprised of the multidrug-resistant strains, or the hypervirulent group, depending on their accessory genome, which determines bacterial pathogenicity and the host immune response. The aim of this survey is to present an overview of the murine models mimicking K. pneumoniae infectious processes (i.e., gastrointestinal colonization, urinary, pulmonary, and systemic infections), and the bacterial functions deployed to colonize and disseminate into the host. These in vivo approaches are pivotal to develop new therapeutics to limit K. pneumoniae infections via a modulation of the immune responses and/or microbiota.
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Abstract
Klebsiella pneumoniae are Gram-negative facultative anaerobes that are found within host-associated commensal microbiomes, but they can also cause a wide range of infections that are often difficult to treat. These infections are caused by different pathotypes of K. pneumoniae, called either classical or hypervirulent strains. Klebsiella pneumoniae are Gram-negative facultative anaerobes that are found within host-associated commensal microbiomes, but they can also cause a wide range of infections that are often difficult to treat. These infections are caused by different pathotypes of K. pneumoniae, called either classical or hypervirulent strains. These two groups are genetically distinct, inhabit nonoverlapping geographies, and cause different types of harmful infections in humans. These distinct bacterial groups have also been found to interact differently with the host immune system. Initial innate immune defenses against K. pneumoniae infection include complement, macrophages, neutrophils, and monocytes; these defenses are primary strategies employed by the host to clear infections. K. pneumoniae pathogenesis depends upon the interactions between the microbe and each of these host defenses, and it is becoming increasingly apparent that bacterial genetic diversity impacts the outcomes of these interactions. Here, we highlight recent advances in our understanding of K. pneumoniae pathogenesis, with a focus on how bacterial evolution and diversity impact K. pneumoniae interactions with mammalian innate immune host defenses. We also discuss outstanding questions regarding how K. pneumoniae can frustrate normal immune responses, capitalize upon states of immunocompromise, and cause infections with high mortality.
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Haim MS, Zaheer R, Bharat A, Di Gregorio S, Di Conza J, Galanternik L, Lubovich S, Golding GR, Graham MR, Van Domselaar G, Cardona ST, Mollerach M. Comparative genomics of ST5 and ST30 methicillin-resistant Staphylococcus aureus sequential isolates recovered from paediatric patients with cystic fibrosis. Microb Genom 2021; 7:mgen000510. [PMID: 33599606 PMCID: PMC8190608 DOI: 10.1099/mgen.0.000510] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 12/21/2020] [Indexed: 12/28/2022] Open
Abstract
Staphylococcus aureus chronic airway infection in patients with cystic fibrosis (CF) allows this pathogen to adapt over time in response to different selection pressures. We have previously shown that the main sequence types related to community-acquired methicillin-resistant S. aureus (MRSA) infections in Argentina - ST5 and ST30 - are also frequently isolated from the sputum of patients with CF, but in these patients they usually display multi-drug antimicrobial resistance. In this study, we sequenced the genomes of MRSA from four paediatric CF patients with the goal of identifying mutations among sequential isolates, especially those possibly related to antimicrobial resistance and virulence, which might contribute to the adaptation of the pathogen in the airways of patients with CF. Our results revealed genetic differences in sequential MRSA strains isolated from patients with CF in both their core and accessory genomes. Although the genetic adaptation of S. aureus was distinct in different hosts, we detected independent mutations in thyA, htrA, rpsJ and gyrA - which are known to have crucial roles in S. aureus virulence and antimicrobial resistance - in isolates recovered from multiple patients. Moreover, we identified allelic variants that were detected in all of the isolates recovered after a certain time point; these non-synonymous mutations were in genes associated with antimicrobial resistance, virulence, iron scavenging and oxidative stress resistance. In conclusion, our results provide evidence of genetic variability among sequential MRSA isolates that could be implicated in the adaptation of these strains during chronic CF airway infection.
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Affiliation(s)
- María Sol Haim
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones en Bacteriología y Virología Molecular, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Rahat Zaheer
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
| | - Amrita Bharat
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
| | - Sabrina Di Gregorio
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones en Bacteriología y Virología Molecular, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - José Di Conza
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones en Bacteriología y Virología Molecular, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | | | - Silvina Lubovich
- Hospital de Niños 'Dr Ricardo Gutiérrez', Buenos Aires, Argentina
| | - George R. Golding
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
- Department of Medical Microbiology and Infectious Disease, University of Manitoba, Winnipeg, Canada
| | - Morag R. Graham
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
- Department of Medical Microbiology and Infectious Disease, University of Manitoba, Winnipeg, Canada
| | - Gary Van Domselaar
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
- Department of Medical Microbiology and Infectious Disease, University of Manitoba, Winnipeg, Canada
| | - Silvia T. Cardona
- Department of Medical Microbiology and Infectious Disease, University of Manitoba, Winnipeg, Canada
- Department of Microbiology, University of Manitoba, Winnipeg, Canada
| | - Marta Mollerach
- Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Investigaciones en Bacteriología y Virología Molecular, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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7
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Sharafutdinov I, Esmaeili DS, Harrer A, Tegtmeyer N, Sticht H, Backert S. Campylobacter jejuni Serine Protease HtrA Cleaves the Tight Junction Component Claudin-8. Front Cell Infect Microbiol 2020; 10:590186. [PMID: 33364202 PMCID: PMC7752809 DOI: 10.3389/fcimb.2020.590186] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/27/2020] [Indexed: 12/12/2022] Open
Abstract
Campylobacter jejuni express the high temperature requirement protein A (HtrA), a secreted serine protease, which is implicated in virulence properties of the pathogen. Previous studies have shown that C. jejuni HtrA can cleave the epithelial transmembrane proteins occludin and E-cadherin in the tight and adherens junctions, respectively. In the present report, we studied the interaction of HtrA with another human tight junction protein, claudin-8. Confocal immunofluorescence experiments have shown that C. jejuni infection of the intestinal polarized epithelial cells in vitro leads to a relocation of claudin-8. Wild-type C. jejuni induced the downregulation of claudin-8 signals in the tight junctions and an accumulation of claudin-8 agglomerates in the cytoplasm, which were not seen during infection with isogenic ΔhtrA knockout deletion or protease-inactive S197A point mutants. Western blotting of protein samples from infected vs. uninfected cells revealed that an 18-kDa carboxy-terminal fragment is cleaved-off from the 26-kDa full-length claudin-8 protein, but not during infection with the isogenic ΔhtrA mutant. These results were confirmed by in vitro cleavage assays using the purified recombinant C. jejuni HtrA and human claudin-8 proteins. Recombinant HtrA cleaved purified claudin-8 in vitro giving rise to the same 18-kDa sized carboxy-terminal cleavage product. Mapping studies revealed that HtrA cleavage occurs in the first extracellular loop of claudin-8. Three-dimensional modeling of the claudin-8 structure identified an exposed HtrA cleavage site between the amino acids alanine 58 and asparagine 59, which is in well agreement with the mapping studies. Taken together, HtrA operates as a secreted virulence factor targeting multiple proteins both in the tight and adherens junctions. This strategy may help the bacteria to open the cell-to-cell junctions, and to transmigrate across the intestinal epithelium by a paracellular mechanism and establish an acute infection.
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Affiliation(s)
- Irshad Sharafutdinov
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Delara Soltan Esmaeili
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Aileen Harrer
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, University of Erlangen-Nuremberg, Erlangen, Germany
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In Silico Structural and Functional Characterization of HtrA Proteins of Leptospira spp.: Possible Implications in Pathogenesis. Trop Med Infect Dis 2020; 5:tropicalmed5040179. [PMID: 33260771 PMCID: PMC7709667 DOI: 10.3390/tropicalmed5040179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 12/14/2022] Open
Abstract
Leptospirosis is a zoonosis caused by the pathogenic bacteria of the genus Leptospira. The identification of conserved outer membrane proteins among pathogenic strains is a major research target in elucidating mechanisms of pathogenicity. Surface-exposed proteins are most probably the ones involved in the interaction of leptospires with the environment. Some spirochetes use outer membrane proteases as a way to penetrate host tissues. HtrA is a family of proteins found in various cell types, from prokaryotes to primates. They are a set of proteases usually composed of a serine protease and PDZ domains, and they are generally transported to the periplasm. Here, we identified four genes—annotated as HtrA, LIC11111, LIC20143, LIC20144 and LIC11037—and another one annotated as a serine protease, LIC11112. It is believed that the last forms a functional heterodimer with LIC11111, since they are organized in one operon. Our analyses showed that these proteins are highly conserved among pathogenic strains. LIC11112, LIC20143, and LIC11037 have the serine protease domain with the conserved catalytic triad His-Asp-Ser. This is the first bioinformatics analysis of HtrA proteins from Leptospira that suggests their proteolytic activity potential. Experimental studies are warranted to elucidate this possibility.
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Capillary leakage provides nutrients and antioxidants for rapid pneumococcal proliferation in influenza-infected lower airways. Proc Natl Acad Sci U S A 2020; 117:31386-31397. [PMID: 33229573 PMCID: PMC7733805 DOI: 10.1073/pnas.2012265117] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Mechanisms for why influenza A virus (IAV) infections sensitize for pneumococcal infections are not clear. Here, we show that IAV-induced capillary leakage results in influx of nutrients and antioxidants to the lungs, thereby promoting pneumococcal growth in the lower respiratory tract. The evoked inflammation leads to redox imbalances that require bacterial adaptation to the oxidized environment, including induction of the pneumococcal chaperone/protease HtrA that protects the bacteria from clearance by the immune system. The results give us insight into the delicate interplay between the bacteria and the host environment during coinfections that needs to be explored in order to find novel therapeutic approaches. Influenza A virus (IAV)-related mortality is often due to secondary bacterial infections, primarily by pneumococci. Here, we study how IAV-modulated changes in the lungs affect bacterial replication in the lower respiratory tract (LRT). Bronchoalveolar lavages (BALs) from coinfected mice showed rapid bacterial proliferation 4 to 6 h after pneumococcal challenge. Metabolomic and quantitative proteomic analyses demonstrated capillary leakage with efflux of nutrients and antioxidants into the alveolar space. Pneumococcal adaptation to IAV-induced inflammation and redox imbalance increased the expression of the pneumococcal chaperone/protease HtrA. Presence of HtrA resulted in bacterial growth advantage in the IAV-infected LRT and protection from complement-mediated opsonophagocytosis due to capsular production. Absence of HtrA led to growth arrest in vitro that was partially restored by antioxidants. Pneumococcal ability to grow in the IAV-infected LRT depends on the nutrient-rich milieu with increased levels of antioxidants such as ascorbic acid and its ability to adapt to and cope with oxidative damage and immune clearance.
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Hu Y, Anes J, Devineau S, Fanning S. Klebsiella pneumoniae: Prevalence, Reservoirs, Antimicrobial Resistance, Pathogenicity, and Infection: A Hitherto Unrecognized Zoonotic Bacterium. Foodborne Pathog Dis 2020; 18:63-84. [PMID: 33124929 DOI: 10.1089/fpd.2020.2847] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Klebsiella pneumoniae is considered an opportunistic pathogen, constituting an ongoing health concern for immunocompromised patients, the elderly, and neonates. Reports on the isolation of K. pneumoniae from other sources are increasing, many of which express multidrug-resistant (MDR) phenotypes. Three phylogroups were identified based on nucleotide differences. Niche environments, including plants, animals, and humans appear to be colonized by different phylogroups, among which KpI (K. pneumoniae) is commonly associated with human infection. Infections with K. pneumoniae can be transmitted through contaminated food or water and can be associated with community-acquired infections or between persons and animals involved in hospital-acquired infections. Increasing reports are describing detections along the food chain, suggesting the possibility exists that this could be a hitherto unexplored reservoir for this opportunistic bacterial pathogen. Expression of MDR phenotypes elaborated by these bacteria is due to the nature of various plasmids carrying antimicrobial resistance (AMR)-encoding genes, and is a challenge to animal, environmental, and human health alike. Raman spectroscopy has the potential to provide for the rapid identification and screening of antimicrobial susceptibility of Klebsiella isolates. Moreover, hypervirulent isolates linked with extraintestinal infections express phenotypes that may support their niche adaptation. In this review, the prevalence, reservoirs, AMR, Raman spectroscopy detection, and pathogenicity of K. pneumoniae are summarized and various extraintestinal infection pathways are further narrated to extend our understanding of its adaptation and survival ability in reservoirs, and associated disease risks.
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Affiliation(s)
- Yujie Hu
- UCD-Centre for Food Safety, UCD School of Public Health, Physiotherapy and Sports Science, Science Centre South, College of Health and Agricultural Sciences, University College Dublin (UCD), Dublin, Ireland.,Key Laboratory of Food Safety Risk Assessment, Ministry of Health, China National Center for Food Safety Risk Assessment, Beijing, China
| | - João Anes
- UCD-Centre for Food Safety, UCD School of Public Health, Physiotherapy and Sports Science, Science Centre South, College of Health and Agricultural Sciences, University College Dublin (UCD), Dublin, Ireland
| | | | - Séamus Fanning
- UCD-Centre for Food Safety, UCD School of Public Health, Physiotherapy and Sports Science, Science Centre South, College of Health and Agricultural Sciences, University College Dublin (UCD), Dublin, Ireland.,Key Laboratory of Food Safety Risk Assessment, Ministry of Health, China National Center for Food Safety Risk Assessment, Beijing, China.,Institute for Global Food Security, Queen's University Belfast, Belfast, United Kingdom
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11
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Zarzecka U, Harrer A, Zawilak-Pawlik A, Skorko-Glonek J, Backert S. Chaperone activity of serine protease HtrA of Helicobacter pylori as a crucial survival factor under stress conditions. Cell Commun Signal 2019; 17:161. [PMID: 31796064 PMCID: PMC6892219 DOI: 10.1186/s12964-019-0481-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/11/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Serine protease HtrA exhibits both proteolytic and chaperone activities, which are involved in cellular protein quality control. Moreover, HtrA is an important virulence factor in many pathogens including Helicobacter pylori, for which the crucial stage of infection is the cleavage of E-cadherin and other cell-to-cell junction proteins. METHODS The in vitro study of H. pylori HtrA (HtrAHp) chaperone activity was carried out using light scattering assays and investigation of lysozyme protein aggregates. We produced H. pylori ∆htrA deletion and HtrAHp point mutants without proteolytic activity in strain N6 and investigated the survival of the bacteria under thermal, osmotic, acidic and general stress conditions as well as the presence of puromycin or metronidazole using serial dilution tests and disk diffusion method. The levels of cellular and secreted proteins were examined using biochemical fraction and Western blotting. We also studied the proteolytic activity of secreted HtrAHp using zymography and the enzymatic digestion of β-casein. Finally, the consequences of E-cadherin cleavage were determined by immunofluorescence microscopy. RESULTS We demonstrate that HtrAHp displays chaperone activity that inhibits the aggregation of lysozyme and is stable under various pH and temperature conditions. Next, we could show that N6 expressing only HtrA chaperone activity grow well under thermal, pH and osmotic stress conditions, and in the presence of puromycin or metronidazole. In contrast, in the absence of the entire htrA gene the bacterium was more sensitive to a number of stresses. Analysing the level of cellular and secreted proteins, we noted that H. pylori lacking the proteolytic activity of HtrA display reduced levels of secreted HtrA. Moreover, we compared the amounts of secreted HtrA from several clinical H. pylori strains and digestion of β-casein. We also demonstrated a significant effect of the HtrAHp variants during infection of human epithelial cells and for E-cadherin cleavage. CONCLUSION Here we identified the chaperone activity of the HtrAHp protein and have proven that this activity is important and sufficient for the survival of H. pylori under multiple stress conditions. We also pinpointed the importance of HtrAHp chaperone activity for E- cadherin degradation and therefore for the virulence of this eminent pathogen.
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Affiliation(s)
- Urszula Zarzecka
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany.,Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Aileen Harrer
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Anna Zawilak-Pawlik
- Department of Microbiology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland
| | - Joanna Skorko-Glonek
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany.
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Jackson-Litteken CD, Zalud AK, Ratliff CT, Latham JI, Bourret TJ, Lopez JE, Blevins JS. Assessing the Contribution of an HtrA Family Serine Protease During Borrelia turicatae Mammalian Infection. Front Cell Infect Microbiol 2019; 9:290. [PMID: 31456953 PMCID: PMC6700303 DOI: 10.3389/fcimb.2019.00290] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 07/26/2019] [Indexed: 12/31/2022] Open
Abstract
Tick-borne relapsing fever (TBRF), characterized by recurring febrile episodes, is globally distributed and among the most common bacterial infections in some African countries. Despite the public health concern that this disease represents, little is known regarding the virulence determinants required by TBRF Borrelia during infection. Because the chromosomes of TBRF Borrelia show extensive colinearity with those of Lyme disease (LD) Borrelia, the exceptions represent unique genes encoding proteins that are potentially essential to the disparate enzootic cycles of these two groups of spirochetes. One such exception is a gene encoding an HtrA family protease, BtpA, that is present in TBRF Borrelia, but not in LD spirochetes. Previous work suggested that btpA orthologs may be important for resistance to stresses faced during mammalian infection. Herein, proteomic analyses of the TBRF spirochete, Borrelia turicatae, demonstrated that BtpA, as well as proteins encoded by adjacent genes in the B. turicatae genome, were produced in response to culture at mammalian body temperature, suggesting a role in mammalian infection. Further, transcriptional analyses revealed that btpA was expressed with the genes immediately upstream and downstream as part of an operon. To directly assess if btpA is involved in resistance to environmental stresses, btpA deletion mutants were generated. btpA mutants demonstrated no growth defect in response to heat shock, but were more sensitive to oxidative stress produced by t-butyl peroxide compared to wild-type B. turicatae. Finally, btpA mutants were fully infectious in a murine relapsing fever (RF) infection model. These results indicate that BtpA is either not required for mammalian infection, or that compensatory mechanisms exist in TBRF spirochetes to combat environmental stresses encountered during mammalian infection in the absence of BtpA.
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Affiliation(s)
- Clay D. Jackson-Litteken
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Amanda K. Zalud
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE, United States
| | - C. Tyler Ratliff
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Jacob I. Latham
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Travis J. Bourret
- Department of Medical Microbiology and Immunology, Creighton University, Omaha, NE, United States
| | - Job E. Lopez
- Section of Tropical Medicine, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, United States
| | - Jon S. Blevins
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, United States,*Correspondence: Jon S. Blevins
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13
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Harrer A, Bücker R, Boehm M, Zarzecka U, Tegtmeyer N, Sticht H, Schulzke JD, Backert S. Campylobacter jejuni enters gut epithelial cells and impairs intestinal barrier function through cleavage of occludin by serine protease HtrA. Gut Pathog 2019; 11:4. [PMID: 30805031 PMCID: PMC6373145 DOI: 10.1186/s13099-019-0283-z] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/01/2019] [Indexed: 01/17/2023] Open
Abstract
Campylobacter jejuni secretes HtrA (high temperature requirement protein A), a serine protease that is involved in virulence. Here, we investigated the interaction of HtrA with the host protein occludin, a tight junction strand component. Immunofluorescence studies demonstrated that infection of polarized intestinal Caco-2 cells with C. jejuni strain 81-176 resulted in a redistribution of occludin away from the tight junctions into the cytoplasm, an effect that was also observed in human biopsies during acute campylobacteriosis. Occludin knockout Caco-2 cells were generated by CRISPR/Cas9 technology. Inactivation of this gene affected the polarization of the cells in monolayers and transepithelial electrical resistance (TER) was reduced, compared to wild-type Caco-2 cells. Although tight junctions were still being formed, occludin deficiency resulted in a slight decrease of the tight junction plaque protein ZO-1, which was redistributed off the tight junction into the lateral plasma membrane. Adherence of C. jejuni to Caco-2 cell monolayers was similar between the occludin knockout compared to wild-type cells, but invasion was enhanced, indicating that deletion of occludin allowed larger numbers of bacteria to pass the tight junctions and to reach basal membranes to target the fibronectin receptor followed by cell entry. Finally, we discovered that purified C. jejuni HtrA cleaves recombinant occludin in vitro to release a 37 kDa carboxy-terminal fragment. The same cleavage fragment was observed in Western blots upon infection of polarized Caco-2 cells with wild-type C. jejuni, but not with isogenic ΔhtrA mutants. HtrA cleavage was mapped to the second extracellular loop of occludin, and a putative cleavage site was identified. In conclusion, HtrA functions as a secreted protease targeting the tight junctions, which enables the bacteria by cleaving occludin and subcellular redistribution of other tight junction proteins to transmigrate using a paracellular mechanism and subsequently invade epithelial cells.
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Affiliation(s)
- Aileen Harrer
- 1Division of Microbiology, Dept. of Biology, University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Roland Bücker
- 2Institut für Klinische Physiologie, Med. Klinik m.S. Gastroenterologie, Infektiologie und Rheumatologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Manja Boehm
- 1Division of Microbiology, Dept. of Biology, University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Urszula Zarzecka
- 1Division of Microbiology, Dept. of Biology, University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany.,4Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, 80-308 Gdansk, Poland
| | - Nicole Tegtmeyer
- 1Division of Microbiology, Dept. of Biology, University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Heinrich Sticht
- 3Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Jörg D Schulzke
- 2Institut für Klinische Physiologie, Med. Klinik m.S. Gastroenterologie, Infektiologie und Rheumatologie, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Steffen Backert
- 1Division of Microbiology, Dept. of Biology, University of Erlangen-Nuremberg, Staudtstr. 5, 91058 Erlangen, Germany
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14
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Antibiotic treatment modulates protein components of cytotoxic outer membrane vesicles of multidrug-resistant clinical strain, Acinetobacter baumannii DU202. Clin Proteomics 2018; 15:28. [PMID: 30186054 PMCID: PMC6118003 DOI: 10.1186/s12014-018-9204-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 08/16/2018] [Indexed: 12/31/2022] Open
Abstract
Background Outer membrane vesicles (OMVs) of Acinetobacter baumannii are cytotoxic and elicit a potent innate immune response. OMVs were first identified in A. baumannii DU202, an extensively drug-resistant clinical strain. Herein, we investigated protein components of A. baumannii DU202 OMVs following antibiotic treatment by proteogenomic analysis. Methods Purified OMVs from A. baumannii DU202 grown in different antibiotic culture conditions were screened for pathogenic and immunogenic effects, and subjected to quantitative proteomic analysis by one-dimensional electrophoresis and liquid chromatography combined with tandem mass spectrometry (1DE-LC-MS/MS). Protein components modulated by imipenem were identified and discussed. Results OMV secretion was increased > twofold following imipenem treatment, and cytotoxicity toward A549 human lung carcinoma cells was elevated. A total of 277 proteins were identified as components of OMVs by imipenem treatment, among which β-lactamase OXA-23, various proteases, outer membrane proteins, β-barrel assembly machine proteins, peptidyl-prolyl cis–trans isomerases and inherent prophage head subunit proteins were significantly upregulated. Conclusion In vitro stress such as antibiotic treatment can modulate proteome components in A. baumannii OMVs and thereby influence pathogenicity. Electronic supplementary material The online version of this article (10.1186/s12014-018-9204-2) contains supplementary material, which is available to authorized users.
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15
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Albrecht N, Tegtmeyer N, Sticht H, Skórko-Glonek J, Backert S. Amino-Terminal Processing of Helicobacter pylori Serine Protease HtrA: Role in Oligomerization and Activity Regulation. Front Microbiol 2018; 9:642. [PMID: 29713313 PMCID: PMC5911493 DOI: 10.3389/fmicb.2018.00642] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 03/19/2018] [Indexed: 12/17/2022] Open
Abstract
The HtrA family of serine proteases is found in most bacteria, and plays an essential role in the virulence of the gastric pathogen Helicobacter pylori. Secreted H. pylori HtrA (HtrA Hp ) cleaves various junctional proteins such as E-cadherin disrupting the epithelial barrier, which is crucial for bacterial transmigration across the polarized epithelium. Recent studies indicated the presence of two characteristic HtrA Hp forms of 55 and 52 kDa (termed p55 and p52, respectively), in worldwide strains. In addition, p55 and p52 were produced by recombinant HtrA Hp , indicating auto-cleavage. However, the cleavage sites and their functional importance are yet unclear. Here, we determined the amino-terminal ends of p55 and p52 by Edman sequencing. Two proteolytic cleavage sites were identified (H46/D47 and K50/D51). Remarkably, the cleavage site sequences are conserved in HtrA Hp from worldwide isolates, but not in other Gram-negative pathogens, suggesting a highly specific assignment in H. pylori. We analyzed the role of the amino-terminal cleavage sites on activity, secretion and function of HtrA Hp . Three-dimensional modeling suggested a trimeric structure and a role of amino-terminal processing in oligomerization and regulation of proteolytic activity of HtrA Hp . Furthermore, point and deletion mutants of these processing sites were generated in the recently reported Campylobacter jejuni ΔhtrA/htrAHp genetic complementation system and the minimal sequence requirements for processing were determined. Polarized Caco-2 epithelial cells were infected with these strains and analyzed by immunofluorescence microscopy. The results indicated that HtrA Hp processing strongly affected the ability of the protease to disrupt the E-cadherin-based cell-to-cell junctions. Casein zymography confirmed that the amino-terminal region is required for maintaining the proteolytic activity of HtrA Hp . Furthermore, we demonstrated that this cleavage influences the secretion of HtrA Hp in the extracellular space as an important prerequisite for its virulence activity. Taken together, our data demonstrate that amino-terminal cleavage of HtrA Hp is conserved in this pathogen and affects oligomerization and thus, secretion and regulatory activities, suggesting an important role in the pathogenesis of H. pylori.
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Affiliation(s)
- Nicole Albrecht
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Nicole Tegtmeyer
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Joanna Skórko-Glonek
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Steffen Backert
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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16
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Phumisantiphong U, Siripanichgon K, Reamtong O, Diraphat P. A novel bacteriocin from Enterococcus faecalis 478 exhibits a potent activity against vancomycin-resistant enterococci. PLoS One 2017; 12:e0186415. [PMID: 29023515 PMCID: PMC5638566 DOI: 10.1371/journal.pone.0186415] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 09/29/2017] [Indexed: 11/18/2022] Open
Abstract
The emergence of multidrug-resistant enterococci (MDRE) and particularly vancomycin-resistant enterococci (VRE) is considered a serious health problem worldwide, causing the need for new antimicrobials. The aim of this study was to discover and characterize bacteriocin against clinical isolates of MDRE and VRE. Over 10,000 bacterial isolates from water, environment and clinical samples were screened. E. faecalis strain 478 isolated from human feces produced the highest antibacterial activity against several MDRE and VRE strains. The optimum condition for bacteriocin production was cultivation in MRS broth at 37°C, pH 5-6 for 16 hours. The bacteriocin-like substance produced from E. faecalis strain EF478 was stable at 60°C for at least 1 hour and retained its antimicrobial activity after storage at -20°C for 1 year, at 4°C for 6 months, and at 25°C for 2 months. A nano-HPLC electrospray ionization multi-stage tandem mass spectrometry (nLC-ESI-MS/MS) analysis showed that the amino acid sequences of the bacteriocin-like substance was similar to serine protease of E. faecalis, gi|488296663 (NCBI database), which has never been reported as a bacteriocin. This study reported a novel bacteriocin with high antibacterial activity against VRE and MDRE.
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Affiliation(s)
| | - Kanokrat Siripanichgon
- Department of Microbiology, Faculty of Public Health, Mahidol University, Bangkok, Thailand
| | - Onrapak Reamtong
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pornphan Diraphat
- Department of Microbiology, Faculty of Public Health, Mahidol University, Bangkok, Thailand
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17
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Harrer A, Boehm M, Backert S, Tegtmeyer N. Overexpression of serine protease HtrA enhances disruption of adherens junctions, paracellular transmigration and type IV secretion of CagA by Helicobacter pylori. Gut Pathog 2017; 9:40. [PMID: 28770008 PMCID: PMC5526239 DOI: 10.1186/s13099-017-0189-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 07/11/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The serine protease HtrA is an important factor for regulating stress responses and protein quality control in bacteria. In recent studies, we have demonstrated that the gastric pathogen Helicobacter pylori can secrete HtrA into the extracellular environment, where it cleaves-off the ectodomain of the tumor suppressor and adherens junction protein E-cadherin on gastric epithelial cells. RESULTS E-cadherin cleavage opens cell-to-cell junctions, allowing paracellular transmigration of the bacteria across polarized monolayers of MKN-28 and Caco-2 epithelial cells. However, rapid research progress on HtrA function is mainly hampered by the lack of ΔhtrA knockout mutants, suggesting that htrA may represent an essential gene in H. pylori. To circumvent this major handicap and to investigate the role of HtrA further, we overexpressed HtrA by introducing a second functional htrA gene copy in the chromosome and studied various virulence properties of the bacteria. The resulting data demonstrate that overexpression of HtrA in H. pylori gives rise to elevated rates of HtrA secretion, cleavage of E-cadherin, bacterial transmigration and delivery of the type IV secretion system (T4SS) effector protein CagA into polarized epithelial cells, but did not affect IL-8 chemokine production or the secretion of vacuolating cytotoxin VacA and γ-glutamyl-transpeptidase GGT. CONCLUSIONS These data provide for the first time genetic evidence in H. pylori that HtrA is a novel major virulence factor controlling multiple pathogenic activities of this important microbe.
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Affiliation(s)
- Aileen Harrer
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Manja Boehm
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Steffen Backert
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
| | - Nicole Tegtmeyer
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, 91058 Erlangen, Germany
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18
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Marsh JW, Ong VA, Lott WB, Timms P, Tyndall JDA, Huston WM. CtHtrA: the lynchpin of the chlamydial surface and a promising therapeutic target. Future Microbiol 2017; 12:817-829. [PMID: 28593794 DOI: 10.2217/fmb-2017-0017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Chlamydia trachomatis is the most prevalent sexually transmitted bacterial infection worldwide and the leading cause of preventable blindness. Reports have emerged of treatment failure, suggesting a need to develop new antibiotics to battle Chlamydia infection. One possible candidate for a new treatment is the protease inhibitor JO146, which is an effective anti-Chlamydia agent that targets the CtHtrA protein. CtHtrA is a lynchpin on the chlamydial cell surface due to its essential and multifunctional roles in the bacteria's stress response, replicative phase of development, virulence and outer-membrane protein assembly. This review summarizes the current understanding of CtHtrA function and presents a mechanistic model that highlights CtHtrA as an effective target for anti-Chlamydia drug development.
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Affiliation(s)
- James W Marsh
- The ithree institute, University of Technology Sydney, Ultimo, 2007, NSW, Australia
| | - Vanissa A Ong
- Institute of Health & Biomedical Innovation (IHBI), Queensland University of Technology (QUT), Brisbane, 4059, QLD, Australia
| | - William B Lott
- Institute of Health & Biomedical Innovation (IHBI), Queensland University of Technology (QUT), Brisbane, 4059, QLD, Australia
| | - Peter Timms
- Faculty of Science, Health, Education & Engineering, University of the Sunshine Coast, Sippy Downs, 4558, QLD, Australia
| | - Joel DA Tyndall
- National School of Pharmacy, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Wilhelmina M Huston
- School of Life Sciences, University of Technology Sydney, Ultimo, 2007, NSW, Australia
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19
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Wessler S, Schneider G, Backert S. Bacterial serine protease HtrA as a promising new target for antimicrobial therapy? Cell Commun Signal 2017; 15:4. [PMID: 28069057 PMCID: PMC5223389 DOI: 10.1186/s12964-017-0162-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 01/04/2017] [Indexed: 12/19/2022] Open
Abstract
Recent studies have demonstrated that the bacterial chaperone and serine protease high temperature requirement A (HtrA) is closely associated with the establishment and progression of several infectious diseases. HtrA activity enhances bacterial survival under stress conditions, but also has direct effects on functions of the cell adhesion protein E-cadherin and extracellular matrix proteins, including fibronectin and proteoglycans. Although HtrA cannot be considered as a pathogenic factor per se, it exhibits favorable characteristics making HtrA a potentially attractive drug target to combat various bacterial infections.
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Affiliation(s)
- Silja Wessler
- Department of Molecular Biology, Division of Microbiology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020 Salzburg, Austria
| | - Gisbert Schneider
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH), Vladimir-Prelog-Weg 4, CH-8093 Zürich, Switzerland
| | - Steffen Backert
- Division of Microbiology, University of Erlangen-Nuremberg, Staudtstr. 5, D-91058 Erlangen, Germany
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20
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HtrA Is Important for Stress Resistance and Virulence in Haemophilus parasuis. Infect Immun 2016; 84:2209-2219. [PMID: 27217419 PMCID: PMC4962635 DOI: 10.1128/iai.00147-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/12/2016] [Indexed: 02/06/2023] Open
Abstract
Haemophilus parasuis is an opportunistic pathogen that causes Glässer's disease in swine, with polyserositis, meningitis, and arthritis. The high-temperature requirement A (HtrA)-like protease, which is involved in protein quality control, has been reported to be a virulence factor in many pathogens. In this study, we showed that HtrA of H. parasuis (HpHtrA) exhibited both chaperone and protease activities. Finally, nickel import ATP-binding protein (NikE), periplasmic dipeptide transport protein (DppA), and outer membrane protein A (OmpA) were identified as proteolytic substrates for HpHtrA. The protease activity reached its maximum at 40°C in a time-dependent manner. Disruption of the htrA gene from strain SC1401 affected tolerance to temperature stress and resistance to complement-mediated killing. Furthermore, increased autoagglutination and biofilm formation were detected in the htrA mutant. In addition, the htrA mutant was significantly attenuated in virulence in the murine model of infection. Together, these data demonstrate that HpHtrA plays an important role in the virulence of H. parasuis.
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21
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Doorduijn DJ, Rooijakkers SHM, van Schaik W, Bardoel BW. Complement resistance mechanisms of Klebsiella pneumoniae. Immunobiology 2016; 221:1102-9. [PMID: 27364766 DOI: 10.1016/j.imbio.2016.06.014] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 06/13/2016] [Accepted: 06/13/2016] [Indexed: 11/15/2022]
Abstract
The current emergence of antibiotic-resistant bacteria causes major problems in hospitals worldwide. To survive within the host, bacterial pathogens exploit several escape mechanisms to prevent detection and killing by the immune system. As a major player in immune defense, the complement system recognizes and destroys bacteria via different effector mechanisms. The complement system can label bacteria for phagocytosis or directly kill Gram-negative bacteria via insertion of a pore-forming complex in the bacterial membrane. The multi-drug resistant pathogen Klebsiella pneumoniae exploits several mechanisms to resist complement. In this review, we present an overview of strategies used by K. pneumoniae to prevent recognition and killing by the complement system. Understanding these complement evasion strategies is crucial for the development of innovative strategies to combat K. pneumoniae.
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Affiliation(s)
- Dennis J Doorduijn
- Department of Medical Microbiology, UMC Utrecht, Heidelberglaan 100 HP G04.614, 3584CX Utrecht, The Netherlands
| | - Suzan H M Rooijakkers
- Department of Medical Microbiology, UMC Utrecht, Heidelberglaan 100 HP G04.614, 3584CX Utrecht, The Netherlands
| | - Willem van Schaik
- Department of Medical Microbiology, UMC Utrecht, Heidelberglaan 100 HP G04.614, 3584CX Utrecht, The Netherlands
| | - Bart W Bardoel
- Department of Medical Microbiology, UMC Utrecht, Heidelberglaan 100 HP G04.614, 3584CX Utrecht, The Netherlands.
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22
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Next-Generation Bacillus anthracis Live Attenuated Spore Vaccine Based on the htrA(-) (High Temperature Requirement A) Sterne Strain. Sci Rep 2016; 6:18908. [PMID: 26732659 PMCID: PMC4702213 DOI: 10.1038/srep18908] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 11/30/2015] [Indexed: 12/17/2022] Open
Abstract
Anthrax is a lethal disease caused by the gram-positive spore-producing bacterium Bacillus anthracis. Live attenuated vaccines, such as the nonencapsulated Sterne strain, do not meet the safety standards mandated for human use in the Western world and are approved for veterinary purposes only. Here we demonstrate that disrupting the htrA gene, encoding the chaperone/protease HtrA (High Temperature Requirement A), in the virulent Bacillus anthracis Vollum strain results in significant virulence attenuation in guinea pigs, rabbits and mice, underlying the universality of the attenuated phenotype associated with htrA knockout. Accordingly, htrA disruption was implemented for the development of a Sterne-derived safe live vaccine compatible with human use. The novel B. anthracis SterneΔhtrA strain secretes functional anthrax toxins but is 10–104-fold less virulent than the Sterne vaccine strain depending on animal model (mice, guinea pigs, or rabbits). In spite of this attenuation, double or even single immunization with SterneΔhtrA spores elicits immune responses which target toxaemia and bacteremia resulting in protection from subcutaneous or respiratory lethal challenge with a virulent strain in guinea pigs and rabbits. The efficacy of the immune-protective response in guinea pigs was maintained for at least 50 weeks after a single immunization.
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23
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Tegtmeyer N, Moodley Y, Yamaoka Y, Pernitzsch SR, Schmidt V, Traverso FR, Schmidt TP, Rad R, Yeoh KG, Bow H, Torres J, Gerhard M, Schneider G, Wessler S, Backert S. Characterisation of worldwide Helicobacter pylori strains reveals genetic conservation and essentiality of serine protease HtrA. Mol Microbiol 2015; 99:925-44. [PMID: 26568477 PMCID: PMC4832355 DOI: 10.1111/mmi.13276] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2015] [Indexed: 12/11/2022]
Abstract
HtrA proteases and chaperones exhibit important roles in periplasmic protein quality control and stress responses. The genetic inactivation of htrA has been described for many bacterial pathogens. However, in some cases such as the gastric pathogen Helicobacter pylori, HtrA is secreted where it cleaves the tumour‐suppressor E‐cadherin interfering with gastric disease development, but the generation of htrA mutants is still lacking. Here, we show that the htrA gene locus is highly conserved in worldwide strains. HtrA presence was confirmed in 992 H. pylori isolates in gastric biopsy material from infected patients. Differential RNA‐sequencing (dRNA‐seq) indicated that htrA is encoded in an operon with two subsequent genes, HP1020 and HP1021. Genetic mutagenesis and complementation studies revealed that HP1020 and HP1021, but not htrA, can be mutated. In addition, we demonstrate that suppression of HtrA proteolytic activity with a newly developed inhibitor is sufficient to effectively kill H. pylori, but not other bacteria. We show that Helicobacter
htrA is an essential bifunctional gene with crucial intracellular and extracellular functions. Thus, we describe here the first microbe in which htrA is an indispensable gene, a situation unique in the bacterial kingdom. HtrA can therefore be considered a promising new target for anti‐bacterial therapy.
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Affiliation(s)
- Nicole Tegtmeyer
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058, Erlangen, Germany.,Institut für Medizinische Mikrobiologie, Otto-von-Guericke Universität Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany
| | - Yoshan Moodley
- Department of Zoology, University of Venda, Private Bag X5050, Thohoyandou, 0950, South Africa.,Konrad-Lorenz-Institut für Vergleichende Verhaltensforschung, Department für Integrative Biologie und Evolution, Veterinärmedizinische Universität Wien, Savoyenstr. 1a, A-1160, Wien, Austria
| | - Yoshio Yamaoka
- Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Dept. Medicine-Gastroenterology, Houston, TX, USA.,Oita University Faculty of Medicine, Dept. Environmental and Preventive Medicine, Yufu, Japan
| | - Sandy Ramona Pernitzsch
- Research Center for Infectious Diseases (ZINF), University of Würzburg, Josef-Schneider-Str. 2/Bau D15, D-97080, Würzburg, Germany
| | - Vanessa Schmidt
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058, Erlangen, Germany
| | - Francisco Rivas Traverso
- Institut für Medizinische Mikrobiologie, Otto-von-Guericke Universität Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany
| | - Thomas P Schmidt
- Department of Molecular Biology, Division of Microbiology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria
| | - Roland Rad
- II Medical Department, Klinikum Rechts der Isar, Technical University Munich, Munich, Germany.,German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Khay Guan Yeoh
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Ho Bow
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Javier Torres
- Unidad de Investigacion en Enfermedades Infecciosas, UMAE Pediatria, IMSS, Mexico City, Mexico
| | - Markus Gerhard
- Institut für Medizinische Mikrobiologie, Immunologie und Hygiene, Technische Universität München, Munich, 81675, Germany
| | - Gisbert Schneider
- ETH Zürich, Institut für Pharmazeutische Wissenschaften, Vladimir-Prelog-Weg 4, CH-8093, Zürich, Switzerland
| | - Silja Wessler
- Department of Molecular Biology, Division of Microbiology, Paris-Lodron University of Salzburg, Billroth Str. 11, A-5020, Salzburg, Austria
| | - Steffen Backert
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058, Erlangen, Germany.,Institut für Medizinische Mikrobiologie, Otto-von-Guericke Universität Magdeburg, Leipziger Str. 44, D-39120, Magdeburg, Germany
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Boehm M, Lind J, Backert S, Tegtmeyer N. Campylobacter jejuni serine protease HtrA plays an important role in heat tolerance, oxygen resistance, host cell adhesion, invasion, and transmigration. Eur J Microbiol Immunol (Bp) 2015; 5:68-80. [PMID: 25883795 DOI: 10.1556/eujmi-d-15-00003] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 01/13/2015] [Indexed: 12/29/2022] Open
Abstract
Campylobacter jejuni is an important pathogen of foodborne illness. Transmigration across the intestinal epithelial barrier and invasion are considered as primary reasons for tissue damage triggered by C. jejuni. Using knockout mutants, it was shown that the serine protease HtrA may be important for stress tolerance and physiology of C. jejuni. HtrA is also secreted in the extra-cellular environment, where it can cleave junctional host cell proteins such as E-cadherin. Aim of the present study was to establish a genetic complementation system in two C. jejuni strains in order to introduce the wild-type htrA gene in trans, test known htrA phenotypes, and provide the basis to perform further mutagenesis. We confirm that reexpression of the htrA wild-type gene in ΔhtrA mutants restored the following phenotypes: 1) C. jejuni growth at high temperature (44 °C), 2) growth under high oxygen stress conditions, 3) expression of proteolytically active HtrA oligomers, 4) secretion of HtrA into the supernatant, 5) cell attachment and invasion, and 6) transmigration across polarized epithelial cells. These results establish a genetic complementation system for htrA in C. jejuni, exclude polar effects in the ΔhtrA mutants, confirm important HtrA properties, and permit the discovery and dissection of new functions.
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Affiliation(s)
- Manja Boehm
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen/Nuremberg Staudtstr. 5, D-91058 Erlangen Germany
| | - Judith Lind
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen/Nuremberg Staudtstr. 5, D-91058 Erlangen Germany
| | - Steffen Backert
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen/Nuremberg Staudtstr. 5, D-91058 Erlangen Germany
| | - Nicole Tegtmeyer
- Department of Biology, Division of Microbiology, Friedrich Alexander University Erlangen/Nuremberg Staudtstr. 5, D-91058 Erlangen Germany
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LytM proteins play a crucial role in cell separation, outer membrane composition, and pathogenesis in nontypeable Haemophilus influenzae. mBio 2015; 6:e02575. [PMID: 25714719 PMCID: PMC4358004 DOI: 10.1128/mbio.02575-14] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
LytM proteins belong to a family of bacterial metalloproteases. In Gram-negative bacteria, LytM factors are mainly reported to have a direct effect on cell division by influencing cleavage and remodeling of peptidoglycan. In this study, mining nontypeable Haemophilus influenzae (NTHI) genomes, three highly conserved open reading frames (ORFs) containing a LytM domain were identified, and the proteins encoded by the ORFs were named YebA, EnvC, and NlpD on the basis of their homology with the Escherichia coli proteins. Immunoblotting and confocal analysis showed that while NTHI NlpD is exposed on the bacterial surface, YebA and EnvC reside in the periplasm. NTHI ΔyebA and ΔnlpD deletion mutants revealed an aberrant division phenotype characterized by an altered cell architecture and extensive membrane blebbing. The morphology of the ΔenvC deletion mutant was identical to that of the wild-type strain, but it showed a drastic reduction of periplasmic proteins, including the chaperones HtrA, SurA, and Skp, and an accumulation of β-barrel-containing outer membrane proteins comprising the autotransporters Hap, IgA serine protease, and HMW2A, as observed by proteomic analysis. These data suggest that EnvC may influence the bacterial surface protein repertoire by facilitating the passage of the periplasmic chaperones through the peptidoglycan layer to the close vicinity of the inner face of the outer membrane. This hypothesis was further corroborated by the fact that an NTHI envC defective strain had an impaired capacity to adhere to epithelial cells and to form biofilm. Notably, this strain also showed a reduced serum resistance. These results suggest that LytM factors are not only important components of cell division but they may also influence NTHI physiology and pathogenesis by affecting membrane composition. Nontypeable Haemophilus influenzae (NTHI) is an opportunistic pathogen that colonizes the human nasopharynx and can cause serious infections in children (acute otitis media) and adults (chronic obstructive pulmonary disease). Several virulence factors are well studied, but the complete scenario of NTHI pathogenesis is still unclear. We identified and characterized three NTHI LytM factors homologous to the Escherichia coli LytM proteins. Although LytM factors are reported to play a crucial role in the cell division process, in NTHI they are also involved in other bacterial functions. In particular, YebA and NlpD are fundamental for membrane stability: indeed, their absence causes an increased release of outer membrane vesicles (OMVs). On the other hand, our data suggest that EnvC could directly or indirectly affect peptidoglycan permeability and consequently, bacterial periplasmic and outer membrane protein distribution. Interestingly, by modulating the surface composition of virulence determinants, EnvC also has an impact on NTHI pathogenesis.
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Protection against Klebsiella pneumoniae using lithium chloride in an intragastric infection model. Antimicrob Agents Chemother 2014; 59:1525-33. [PMID: 25534739 DOI: 10.1128/aac.04261-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Intragastric Klebsiella pneumoniae infections of mice can cause liver abscesses, necrosis of liver tissues, and bacteremia. Lithium chloride, a widely prescribed drug for bipolar mood disorder, has been reported to possess anti-inflammatory properties. Using an intragastric infection model, the effects of LiCl on K. pneumoniae infections were examined. Providing mice with drinking water containing LiCl immediately after infection protected them from K. pneumoniae-induced death and liver injuries, such as necrosis of liver tissues, as well as increasing blood levels of aspartate aminotransferase and alanine aminotransferase, in a dose-dependent manner. LiCl administered as late as 24 h postinfection still provided protection. Monitoring of the LiCl concentrations in the sera of K. pneumoniae-infected mice showed that approximately 0.33 mM LiCl was the most effective dose for protecting mice against infections, which is lower than the clinically toxic dose of LiCl. Surveys of bacterial counts and cytokine expression levels in LiCl-treated mice revealed that both were effectively inhibited in blood and liver tissues. Using in vitro assays, we found that LiCl (5 μM to 1 mM) did not directly interfere with the growth of K. pneumoniae but made K. pneumoniae cells lose the mucoid phenotype and become more susceptible to macrophage killing. Furthermore, low doses of LiCl also partially enhanced the bactericidal activity of macrophages. Taken together, these data suggest that LiCl is an alternative therapeutic agent for K. pneumoniae-induced liver infections.
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Roberts DM, Personne Y, Ollinger J, Parish T. Proteases in Mycobacterium tuberculosis pathogenesis: potential as drug targets. Future Microbiol 2013; 8:621-31. [PMID: 23642117 DOI: 10.2217/fmb.13.25] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
TB is still a major global health problem causing over 1 million deaths per year. An increasing problem of drug resistance in the causative agent, Mycobacterium tuberculosis, as well as problems with the current lengthy and complex treatment regimens, lends urgency to the need to develop new antitubercular agents. Proteases have been targeted for therapy in other infections, most notably these have been successful as antiviral agents in the treatment of HIV infection. M. tuberculosis has a number of proteases with good potential as novel drug targets and developing drugs against these should result in agents that are effective against drug-resistant and drug-sensitive strains. In this review, the authors summarize the current status of proteases with potential as drug targets in this pathogen, particularly focusing on proteases involved in protein secretion (signal peptidases LepB and LspA), protein degradation and turnover (ClpP and the proteasome) and virulence (mycosins and HtrA).
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Affiliation(s)
- David M Roberts
- TB Discovery Research, Infectious Disease Research Institute, Seattle, WA, USA
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Involvement of lipid rafts in the budding-like exit of Orientia tsutsugamushi. Microb Pathog 2013; 63:37-43. [DOI: 10.1016/j.micpath.2013.06.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 06/05/2013] [Indexed: 01/20/2023]
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29
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Dutta A, Katarkar A, Chaudhuri K. In-silico structural and functional characterization of a V. cholerae O395 hypothetical protein containing a PDZ1 and an uncommon protease domain. PLoS One 2013; 8:e56725. [PMID: 23441214 PMCID: PMC3575494 DOI: 10.1371/journal.pone.0056725] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 01/14/2013] [Indexed: 11/18/2022] Open
Abstract
Vibrio cholerae, the causative agent of epidemic cholera, has been a constant source of concern for decades. It has constantly evolved itself in order to survive the changing environment. Acquisition of new genetic elements through genomic islands has played a major role in its evolutionary process. In this present study a hypothetical protein was identified which was present in one of the predicted genomic island regions of the large chromosome of V. cholerae O395 showing a strong homology with a conserved phage encoded protein. In-silico physicochemical analysis revealed that the hypothetical protein was a periplasmic protein. Homology modeling study indicated that the hypothetical protein was an unconventional and atypical serine protease belonging to HtrA protein family. The predicted 3D-model of the hypothetical protein revealed a catalytic centre serine utilizing a single catalytic residue for proteolysis. The predicted catalytic triad may help to deduce the active site for the recruitment of the substrate for proteolysis. The active site arrangements of this predicted serine protease homologue with atypical catalytic triad is expected to allow these proteases to work in different environments of the host.
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Affiliation(s)
- Avirup Dutta
- CSIR-SRF, Molecular and Human Genetics Division, CSIR - Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Atul Katarkar
- ICMR-SRF, Molecular and Human Genetics Division, CSIR - Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - Keya Chaudhuri
- Chief Scientist, Molecular and Human Genetics Division, and Head Academic Affairs Division, CSIR - Indian Institute of Chemical Biology, Kolkata, West Bengal, India
- * E-mail:
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Singh N, Kuppili RR, Bose K. The structural basis of mode of activation and functional diversity: a case study with HtrA family of serine proteases. Arch Biochem Biophys 2011; 516:85-96. [PMID: 22027029 DOI: 10.1016/j.abb.2011.10.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 10/03/2011] [Indexed: 12/15/2022]
Abstract
HtrA (High temperature requirement protease A) proteins that are primarily involved in protein quality control belong to a family of serine proteases conserved from bacteria to humans. HtrAs are oligomeric proteins that share a common trimeric pyramidal architecture where each monomer comprises a serine protease domain and one or two PDZ domains. Although the overall structural integrity is well maintained and they exhibit similar mechanism of activation, subtle conformational changes and structural plasticity especially in the flexible loop regions and domain interfaces lead to differences in their active site conformation and hence in their specificity and functions.
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Affiliation(s)
- Nitu Singh
- Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai, India
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31
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Huang CH, Chiou SH. Proteomic analysis of upregulated proteins in Helicobacter pylori under oxidative stress induced by hydrogen peroxide. Kaohsiung J Med Sci 2011; 27:544-53. [DOI: 10.1016/j.kjms.2011.06.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 04/18/2011] [Indexed: 01/03/2023] Open
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Bæk KT, Vegge CS, Brøndsted L. HtrA chaperone activity contributes to host cell binding in Campylobacter jejuni. Gut Pathog 2011; 3:13. [PMID: 21939552 PMCID: PMC3260087 DOI: 10.1186/1757-4749-3-13] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 09/22/2011] [Indexed: 11/25/2022] Open
Abstract
Background Acute gastroenteritis caused by the food-borne pathogen Campylobacter jejuni is associated with attachment of bacteria to the intestinal epithelium and subsequent invasion of epithelial cells. In C. jejuni, the periplasmic protein HtrA is required for efficient binding to epithelial cells. HtrA has both protease and chaperone activity, and is important for virulence of several bacterial pathogens. Results The aim of this study was to determine the role of the dual activities of HtrA in host cell interaction of C. jejuni by comparing an htrA mutant lacking protease activity, but retaining chaperone activity, with a ΔhtrA mutant and the wild type strain. Binding of C. jejuni to both epithelial cells and macrophages was facilitated mainly by HtrA chaperone activity that may be involved in folding of outer membrane adhesins. In contrast, HtrA protease activity played only a minor role in interaction with host cells. Conclusion We show that HtrA protease and chaperone activities contribute differently to C. jejuni's interaction with mammalian host cells, with the chaperone activity playing the major role in host cell binding.
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Affiliation(s)
- Kristoffer T Bæk
- Department of Veterinary Disease Biology, University Copenhagen, Stigbøjlen 4, DK-1870 Frederiksberg C, Denmark.
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Sawa J, Malet H, Krojer T, Canellas F, Ehrmann M, Clausen T. Molecular adaptation of the DegQ protease to exert protein quality control in the bacterial cell envelope. J Biol Chem 2011; 286:30680-30690. [PMID: 21685389 PMCID: PMC3162429 DOI: 10.1074/jbc.m111.243832] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2011] [Revised: 06/07/2011] [Indexed: 11/06/2022] Open
Abstract
To react to distinct stress situations and to prevent the accumulation of misfolded proteins, all cells employ a number of proteases and chaperones, which together set up an efficient protein quality control system. The functionality of proteins in the cell envelope of Escherichia coli is monitored by the HtrA proteases DegS, DegP, and DegQ. In contrast with DegP and DegS, the structure and function of DegQ has not been addressed in detail. Here, we show that substrate binding triggers the conversion of the resting DegQ hexamer into catalytically active 12- and 24-mers. Interestingly, substrate-induced oligomer reassembly and protease activation depends on the first PDZ domain but not on the second. Therefore, the regulatory mechanism originally identified in DegP should be a common feature of HtrA proteases, most of which encompass only a single PDZ domain. Using a DegQ mutant lacking the second PDZ domain, we determined the high resolution crystal structure of a dodecameric HtrA complex. The nearly identical domain orientation of protease and PDZ domains within 12- and 24-meric HtrA complexes reveals a conserved PDZ1 → L3 → LD/L1/L2 signaling cascade, in which loop L3 senses the repositioned PDZ1 domain of higher order, substrate-engaged particles and activates protease function. Furthermore, our in vitro and in vivo data imply a pH-related function of DegQ in the bacterial cell envelope.
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Affiliation(s)
- Justyna Sawa
- Institute of Molecular Pathology, A-1030 Vienna, Austria
| | - Hélène Malet
- Department of Biological Sciences, Institute of Structural Molecular Biology, Birkbeck College, London WC1E 7HX, United Kingdom
| | - Tobias Krojer
- Institute of Molecular Pathology, A-1030 Vienna, Austria
| | | | - Michael Ehrmann
- Centre for Medical Biotechnology, Faculty of Biology and Geography, University Duisburg-Essen, 45117 Essen, Germany
| | - Tim Clausen
- Institute of Molecular Pathology, A-1030 Vienna, Austria.
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Experimental phage therapy in treating Klebsiella pneumoniae-mediated liver abscesses and bacteremia in mice. Antimicrob Agents Chemother 2011; 55:1358-65. [PMID: 21245450 DOI: 10.1128/aac.01123-10] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Intragastric inoculation of mice with Klebsiella pneumoniae can cause liver abscesses, necrosis of liver tissues, and bacteremia. A newly isolated phage (φNK5) with lytic activity for K. pneumoniae was used to treat K. pneumoniae infection in an intragastric model. Both intraperitoneal and intragastric administration of a single dose of φNK5 lower than 2 × 10(8) PFU at 30 min after K. pneumoniae infection was able to protect mice from death in a dose-dependent manner, but the efficacy achieved with a low dose of φNK5 by intragastric treatment provided the more significant protection. Phage φNK5 administered as late as 24 h after K. pneumoniae inoculation was still protective, while intraperitoneal treatment with phage was more efficient than intragastric treatment as a result of the dissemination of bacteria into the circulation at 24 h postinfection. Surveys of bacterial counts for mice treated with φNK5 by the intraperitoneal route revealed that the bacteria were eliminated effectively from both blood and liver tissue. K. pneumoniae-induced liver injury, such as liver necrosis, as well as blood levels of aspartate aminotransferase and alanine aminotransferase and inflammatory cytokine production, was significantly inhibited by φNK5 treatment. These data suggest that a low dose of φNK5 is a potential therapeutic agent for K. pneumoniae-induced liver infection.
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Different contributions of HtrA protease and chaperone activities to Campylobacter jejuni stress tolerance and physiology. Appl Environ Microbiol 2010; 77:57-66. [PMID: 21075890 DOI: 10.1128/aem.01603-10] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The microaerophilic bacterium Campylobacter jejuni is the most common cause of bacterial food-borne infections in the developed world. Tolerance to environmental stress relies on proteases and chaperones in the cell envelope, such as HtrA and SurA. HtrA displays both chaperone and protease activities, but little is known about how each of these activities contributes to stress tolerance in bacteria. In vitro experiments showed temperature-dependent protease and chaperone activities of C. jejuni HtrA. A C. jejuni mutant lacking only the protease activity of HtrA was used to show that the HtrA chaperone activity is sufficient for growth at high temperature or under oxidative stress, whereas the HtrA protease activity is essential only under conditions close to the growth limit for C. jejuni. However, the protease activity was required to prevent induction of the cytoplasmic heat shock response even under optimal growth conditions. Interestingly, the requirement of HtrA at high temperatures was found to depend on the oxygen level, and our data suggest that HtrA may protect oxidatively damaged proteins. Finally, protease activity stimulates HtrA production and oligomer formation, suggesting that a regulatory role depends on the protease activity of HtrA. Studying a microaerophilic organism encoding only two known periplasmic chaperones (HtrA and SurA) revealed an efficient HtrA chaperone activity and proposed multiple roles of the protease activity, increasing our understanding of HtrA in bacterial physiology.
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Lewis C, Skovierova H, Rowley G, Rezuchova B, Homerova D, Stevenson A, Spencer J, Farn J, Kormanec J, Roberts M. Salmonella enterica Serovar Typhimurium HtrA: regulation of expression and role of the chaperone and protease activities during infection. MICROBIOLOGY-SGM 2009; 155:873-881. [PMID: 19246758 DOI: 10.1099/mic.0.023754-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
HtrA is a bifunctional stress protein required by many bacterial pathogens to successfully cause infection. Salmonella enterica serovar Typhimurium (S. Typhimurium) htrA mutants are defective in intramacrophage survival and are highly attenuated in mice. Transcription of htrA in Escherichia coli is governed by a single promoter that is dependent on sigma(E) (RpoE). S. Typhimurium htrA also possesses a sigma(E)-dependent promoter; however, we found that the absence of sigma(E) had little effect on production of HtrA by S. Typhimurium. This suggests that additional promoters control expression of htrA in S. Typhimurium. We identified three S. Typhimurium htrA promoters. Only the most proximal promoter, htrAp3, was sigma(E) dependent. The other promoters, htrAp1 and htrAp2, are probably recognized by the principal sigma factor sigma(70). These two promoters were constitutively expressed but were also slightly induced by heat shock. Thus expression of htrA is different in S. Typhimurium and E. coli. The role of HtrA is to deal with misfolded/damaged proteins in the periplasm. It can do this either by degrading (protease activity) or folding/capturing (chaperone/sequestering, C/S, activity) the aberrant protein. We investigated which of these functions are important to S. Typhimurium in vitro and in vivo. Point or deletion mutants of htrA that encode variant HtrA molecules have been used in previous studies to investigate the role of different regions of HtrA in C/S and protease activity. These htrA variants were placed under the control of the S. Typhimurium htrAP123 promoters and expressed in a S. Typhimurium htrA mutant, GVB1343. Both wild-type HtrA and HtrA (HtrA S210A) lacking protease activity enabled GVB1343 to grow at high temperature (46 degrees C). Both molecules also significantly enhanced the growth/survival of GVB1343 in the liver and spleen of mice during infection. However, expression of wild-type HtrA enabled GVB1343 to grow to much higher levels than expression of HtrA S210A. Thus both the protease and C/S functions of HtrA operate in vivo during infection but the protease function is probably more important. Absence of either PDZ domain completely abolished the ability of HtrA to complement the growth defects of GVB1343 in vitro or in vivo.
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Affiliation(s)
- Claire Lewis
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Henrieta Skovierova
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Gary Rowley
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Bronislava Rezuchova
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Dagmar Homerova
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Andrew Stevenson
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Janice Spencer
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Jacinta Farn
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - Jan Kormanec
- Institute of Molecular Biology, Slovak Academy of Science, Dubravska cesta 21, 845 51 Bratislava, Slovak Republik
| | - Mark Roberts
- Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
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Lo AW, Seers CA, Boyce JD, Dashper SG, Slakeski N, Lissel JP, Reynolds EC. Comparative transcriptomic analysis of Porphyromonas gingivalis biofilm and planktonic cells. BMC Microbiol 2009; 9:18. [PMID: 19175941 PMCID: PMC2637884 DOI: 10.1186/1471-2180-9-18] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Accepted: 01/29/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Porphyromonas gingivalis in subgingival dental plaque, as part of a mature biofilm, has been strongly implicated in the onset and progression of chronic periodontitis. In this study using DNA microarray we compared the global gene expression of a P. gingivalis biofilm with that of its planktonic counterpart grown in the same continuous culture. RESULTS Approximately 18% (377 genes, at 1.5 fold or more, P-value < 0.01) of the P. gingivalis genome was differentially expressed when the bacterium was grown as a biofilm. Genes that were down-regulated in biofilm cells, relative to planktonic cells, included those involved in cell envelope biogenesis, DNA replication, energy production and biosynthesis of cofactors, prosthetic groups and carriers. A number of genes encoding transport and binding proteins were up-regulated in P. gingivalis biofilm cells. Several genes predicted to encode proteins involved in signal transduction and transcriptional regulation were differentially regulated and may be important in the regulation of biofilm growth. CONCLUSION This study analyzing global gene expression provides insight into the adaptive response of P. gingivalis to biofilm growth, in particular showing a down regulation of genes involved in growth and metabolic activity.
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Affiliation(s)
- Alvin W Lo
- Cooperative Research Centre for Oral Health Science, Melbourne Dental School and the Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia.
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Jin H, Wan Y, Zhou R, Li L, Luo R, Zhang S, Hu J, Langford PR, Chen H. Identification of genes transcribed byHaemophilus parasuisin necrotic porcine lung through the selective capture of transcribed sequences (SCOTS). Environ Microbiol 2008; 10:3326-36. [DOI: 10.1111/j.1462-2920.2008.01729.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Yuan L, Rodrigues PH, Bélanger M, Dunn WA, Progulske-Fox A. Porphyromonas gingivalis htrA is involved in cellular invasion and in vivo survival. MICROBIOLOGY-SGM 2008; 154:1161-1169. [PMID: 18375808 DOI: 10.1099/mic.0.2007/015131-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
HtrA is a heat-stress protein that functions both as a chaperone and as a serine protease. HtrA has been shown in several organisms to be involved in responses to stressful environmental conditions and involvement of HtrA in virulence has been reported in pathogenic species. A Porphyromonas gingivalis htrA mutant demonstrated no significant difference to the W83 parent strain when subjected to high temperature and pH values from 3 to 11. However, the htrA mutant showed increased sensitivity to H(2)O(2). Cell invasion assays indicated that the total interaction (adherence) with KB cells, human coronary artery endothelial cells and gingival epithelial cells (GEC) was the same for both the wild-type and the htrA mutant. However, the htrA mutant showed increased invasion in KB cells and GEC. Microarray experiments indicated that a total of 253 genes were differentially regulated in the htrA mutant, including a group of stress-related genes, which might be responsible for the observed decreased resistance to H(2)O(2). In animal experiments, a competition assay showed that the htrA mutant did not survive as well as the wild-type. In another in vivo assay, fewer mice infected with the htrA mutant died than mice infected with W83, suggesting that the htrA gene is virulence-related. These data indicate that the htrA gene in P. gingivalis does not relate to stress conditions such as high temperature and pH, but rather to H(2)O(2) stress. The htrA gene also appears to be important for virulence and survival in in vivo animal models.
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Affiliation(s)
- Lihui Yuan
- Department of Oral Biology, College of Dentistry and Center for Molecular Microbiology, University of Florida, Gainesville, FL 32610, USA
| | - Paulo H Rodrigues
- Department of Oral Biology, College of Dentistry and Center for Molecular Microbiology, University of Florida, Gainesville, FL 32610, USA
| | - Myriam Bélanger
- Department of Oral Biology, College of Dentistry and Center for Molecular Microbiology, University of Florida, Gainesville, FL 32610, USA
| | - William A Dunn
- Department of Anatomy and Cell Biology, College of Medicine and Center for Molecular Microbiology, University of Florida, Gainesville, FL 32610, USA
| | - Ann Progulske-Fox
- Department of Oral Biology, College of Dentistry and Center for Molecular Microbiology, University of Florida, Gainesville, FL 32610, USA
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Mohamedmohaideen NN, Palaninathan SK, Morin PM, Williams BJ, Braunstein M, Tichy SE, Locker J, Russell DH, Jacobs WR, Sacchettini JC. Structure and function of the virulence-associated high-temperature requirement A of Mycobacterium tuberculosis. Biochemistry 2008; 47:6092-102. [PMID: 18479146 DOI: 10.1021/bi701929m] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The high-temperature requirement A (HtrA) family of serine proteases has been shown to play an important role in the environmental and cellular stress damage control system in Escherichia coli. Mycobacterium tuberculosis ( Mtb) has three putative HtrA-like proteases, HtrA1, HtrA2, and HtrA3. The deletion of htrA2 gives attenuated virulence in a mouse model of TB. Biochemical analysis reveals that HtrA2 can function both as a protease and as a chaperone. The three-dimensional structure of HtrA2 determined at 2.0 A resolution shows that the protease domains form the central core of the trimer and the PDZ domains extend to the periphery. Unlike E. coli DegS and DegP, the protease is naturally active due to the formation of the serine protease-like catalytic triad and its uniquely designed oxyanion hole. Both protease and PDZ binding pockets of each HtrA2 molecule are occupied by autoproteolytic peptide products and reveal clues for a novel autoregulatory mechanism that might have significant importance in HtrA-associated virulence of Mtb.
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41
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Sabra W, Hassan M. Exopolysaccharide Yield as a Kinetic Parameter for the Statistical Optimization of EPS Production by Klebsiella pneumoniae. ACTA ACUST UNITED AC 2008. [DOI: 10.3923/biotech.2008.27.34] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Kuo CF, Wang YH, Lei HY, Wang CH, Tsao N. Concanavalin A protects mice from a lethal inoculation of intragastric Klebsiella pneumoniae and reduces the induced liver damage. Antimicrob Agents Chemother 2007; 51:3122-30. [PMID: 17606678 PMCID: PMC2043212 DOI: 10.1128/aac.01379-06] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Intragastric inoculation of Klebsiella pneumoniae can cause invasive diseases, including necrosis of liver tissues and bacteremia. The effect of concanavalin A (ConA) on K. pneumoniae was tested. Pretreatment with ConA was able to protect mice from K. pneumoniae infection in an intragastric model. K. pneumoniae-induced mouse death and liver injury such as liver necrosis, as well as blood levels of aspartate aminotransferase and alanine aminotransferase, were inhibited in a dose-dependent manner by ConA. ConA administered intravenously as late as 24 h after K. pneumoniae inoculation was still protective. In an in vitro assay, ConA was able to bind K. pneumoniae cells directly and further agglutinate them but had no effect on their in vitro growth. Surveys of bacterial counts of ConA-treated mice revealed that the bacteria were eliminated effectively in both blood and liver tissues. Furthermore, the bactericidal activity of macrophages against K. pneumoniae was also enhanced in a dose-dependent manner by ConA in an in vitro culture. These data suggest that ConA is a potentially therapeutic agent for K. pneumoniae-induced liver infection.
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Affiliation(s)
- Chih-Feng Kuo
- Department of Nursing, I-Shou University, Kaohsiung County, Taiwan
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Huston WM, Swedberg JE, Harris JM, Walsh TP, Mathews SA, Timms P. The temperature activated HtrA protease from pathogen Chlamydia trachomatis acts as both a chaperone and protease at 37 degrees C. FEBS Lett 2007; 581:3382-6. [PMID: 17604025 DOI: 10.1016/j.febslet.2007.06.039] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Accepted: 06/15/2007] [Indexed: 11/22/2022]
Abstract
Characterization of the protease, HtrA, from pathogen Chlamydia trachomatis is presented. The purified recombinant protein was a serine endoprotease, specific for unfolded proteins, and temperature activated above 34 degrees C. Chaperone activity was observed, although this appeared target-dependent. Inactive protease (S247A) was able to chaperone insulin B-chain, irrespective of temperature, but at 30 degrees C only HtrA and not S247A displayed significant chaperone activity for alpha-lactalbumin. These data demonstrate that chaperone activity may involve functional protease domain and that C. trachomatis HtrA functions as both a chaperone and protease at 37 degrees C. These properties are consistent with the developmental cycle of this obligate intracellular bacterium.
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Affiliation(s)
- Wilhelmina M Huston
- Institute of Health and Biomedical Innovation and School of Life Sciences, Faculty of Science, Queensland University of Technology, Brisbane, Australia
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Chitlaru T, Gat O, Grosfeld H, Inbar I, Gozlan Y, Shafferman A. Identification of in vivo-expressed immunogenic proteins by serological proteome analysis of the Bacillus anthracis secretome. Infect Immun 2007; 75:2841-52. [PMID: 17353282 PMCID: PMC1932864 DOI: 10.1128/iai.02029-06] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2006] [Revised: 02/15/2007] [Accepted: 03/04/2007] [Indexed: 01/24/2023] Open
Abstract
In a previous comparative proteomic study of Bacillus anthracis examining the influence of the virulence plasmids and of various growth conditions on the composition of the bacterial secretome, we identified 64 abundantly expressed proteins (T. Chitlaru, O. Gat, Y. Gozlan, N. Ariel, and A. Shafferman, J. Bacteriol. 188:3551-3571, 2006). Using a battery of sera from B. anthracis-infected animals, in the present study we demonstrated that 49 of these proteins are immunogenic. Thirty-eight B. anthracis immunogens are documented in this study for the first time. The relative immunogenicities of the 49 secreted proteins appear to span a >10,000-fold range. The proteins eliciting the highest humoral response in the course of infection include, in addition to the well-established immunogens protective antigen (PA), Sap, and EA1, GroEL (BA0267), AhpC (BA0345), MntA (BA3189), HtrA (BA3660), 2,3-cyclic nucleotide diesterase (BA4346), collagen adhesin (BAS5205), an alanine amidase (BA0898), and an endopeptidase (BA1952), as well as three proteins having unknown functions (BA0796, BA0799, and BA0307). Of these 14 highly potent secreted immunogens, 11 are known to be associated with virulence and pathogenicity in B. anthracis or in other bacterial pathogens. Combining the results reported here with the results of a similar study of the membranal proteome of B. anthracis (T. Chitlaru, N. Ariel, A. Zvi, M. Lion, B. Velan, A. Shafferman, and E. Elhanany, Proteomics 4:677-691, 2004) and the results obtained in a functional genomic search for immunogens (O. Gat, H. Grosfeld, N. Ariel, I. Inbar, G. Zaide, Y. Broder, A. Zvi, T. Chitlaru, Z. Altboum, D. Stein, S. Cohen, and A. Shafferman, Infect. Immun. 74:3987-4001, 2006), we generated a list of 84 in vivo-expressed immunogens for future evaluation for vaccine development, diagnostics, and/or therapeutic intervention. In a preliminary study, the efficacies of eight immunogens following DNA immunization of guinea pigs were compared to the efficacy of a PA DNA vaccine. All eight immunogens induced specific high antibody titers comparable to the titers elicited by PA; however, unlike PA, none of them provided protection against a lethal challenge (50 50% lethal doses) of virulent B. anthracis strain Vollum spores.
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Affiliation(s)
- Theodor Chitlaru
- Israel Institute for Biological Research, P.O. Box 19, Ness-Ziona 74100, Israel
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Abstract
The surface proteins of Ehrlichia chaffeensis provide an important interface for pathogen-host interactions. To investigate the surface proteins of E. chaffeensis, membrane-impermeable, cleavable Sulfo-NHS-SS-Biotin was used to label intact bacteria. The biotinylated bacterial surface proteins were isolated by streptavidin-agarose affinity purification. The affinity-captured proteins were separated by electrophoresis, and five relatively abundant protein bands containing immunoreactive proteins were subjected to capillary-liquid chromatography-nanospray tandem mass spectrometry analysis. Nineteen out of 22 OMP-1/P28 family proteins, including P28 (which previously was shown to be surface exposed), were detected in E. chaffeensis cultured in human monocytic leukemia THP-1 cells. For the first time, with the exception of P28 and P28-1, 17 OMP-1/P28 family proteins were demonstrated to be expressed at the protein level. The surface exposure of OMP-1A and OMP-1N was verified by immunofluorescence microscopy. OMP-1B was undetectable either by surface biotinylation or by Western blotting of the whole bacterial lysate, suggesting that it is not expressed by E. chaffeensis cultured in THP-1 cells. Additional E. chaffeensis surface proteins detected were OMP85, hypothetical protein ECH_0525 (here named Esp73), immunodominant surface protein gp47, and 11 other proteins. The identification of E. chaffeensis surface-exposed proteins provides novel insights into the E. chaffeensis surface and lays the foundation for rational studies on pathogen-host interactions and vaccine development.
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Affiliation(s)
- Yan Ge
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210, USA
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Roy F, Vanterpool E, Fletcher HM. HtrA in Porphyromonas gingivalis can regulate growth and gingipain activity under stressful environmental conditions. MICROBIOLOGY (READING, ENGLAND) 2006; 152:3391-3398. [PMID: 17074908 DOI: 10.1099/mic.0.29147-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In several micro-organisms, HtrA, a serine periplasmic protease, is considered an important virulence factor that plays a regulatory role in oxidative and temperature stress. The authors have previously shown that the vimA gene product is an important virulence regulator in Porphyromonas gingivalis. Further, purified recombinant VimA physically interacted with the major gingipains and the HtrA from P. gingivalis. To further evaluate a role for HtrA in the pathogenicity of this organism, a 1.5 kb fragment containing the htrA gene was PCR-amplified from the chromosomal DNA of P. gingivalis W83. This gene was insertionally inactivated using the ermF-ermAM antibiotic-resistance cassette and used to create an htrA-deficient mutant by allelic exchange. In one randomly chosen isogenic mutant designated P. gingivalis FLL203, there was increased sensitivity to hydrogen peroxide. Growth of this mutant at an elevated temperature was more inhibited compared to the wild-type. Further, in contrast to the wild-type, there was a significant decrease in Arg-gingipain activity after heat shock in FLL203. However, the gingipain activity in the mutant returned to normal levels after a further 30 min incubation at room temperature. Collectively, these data suggest that HtrA may play a similar role in oxidative and temperature stress in P. gingivalis as observed in other organisms.
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Affiliation(s)
- F Roy
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - E Vanterpool
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - H M Fletcher
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
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Vanterpool E, Roy F, Zhan W, Sheets SM, Sangberg L, Fletcher HM. VimA is part of the maturation pathway for the major gingipains of Porphyromonas gingivalis W83. Microbiology (Reading) 2006; 152:3383-3389. [PMID: 17074907 DOI: 10.1099/mic.0.29146-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The authors have shown previously that the vimA gene, which is part of the bcp-recA-vimA operon, plays an important role in protease activation in Porphyromonas gingivalis. The gingipain RgpB proenzyme is secreted in the vimA-defective mutant P. gingivalis FLL92. An important question that is raised is whether the vimA gene product could directly interact with the proteases for their activation or regulate a pathway responsible for protease activation. To further study the mechanism(s) of VimA-dependent protease activation, the vimA gene product was further characterized. A 39 kDa protein consistent with the size of the predicted VimA protein was purified. In protein–protein interaction studies, the VimA protein was shown to interact with gingipains RgpA, RgpB and Kgp. Immune sera from mice immunized with P. gingivalis immunoreacted with the purified VimA protein. Taken together, these data suggest an interaction of VimA with the gingipains and further confirm the role of this protein in their regulation or maturation.
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Affiliation(s)
- E Vanterpool
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - F Roy
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - W Zhan
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - S M Sheets
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - L Sangberg
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - H M Fletcher
- Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
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Mo E, Peters SE, Willers C, Maskell DJ, Charles IG. Single, double and triple mutants of Salmonella enterica serovar Typhimurium degP (htrA), degQ (hhoA) and degS (hhoB) have diverse phenotypes on exposure to elevated temperature and their growth in vivo is attenuated to different extents. Microb Pathog 2006; 41:174-82. [PMID: 16949246 DOI: 10.1016/j.micpath.2006.07.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Accepted: 07/11/2006] [Indexed: 11/23/2022]
Abstract
DegP (HtrA) is a well-studied protease involved in survival of bacteria under stress conditions in vitro and in vivo. There are two paralogues of DegP in the Salmonella enterica serovar Typhimurium genome, DegQ and DegS. In order to understand more about the biological significance of this gene family, a series of deg-deletion mutants was generated in S. Typhimurium strain SL3261 by allelic replacement. At elevated temperature in vitro, the viability of degP and degS mutants was reduced when compared with the parent strain whereas the viability of a degQ mutant was not significantly affected. The viability of a double degP-degS mutant at elevated temperature was severely decreased when compared with the respective single mutants or, interestingly, with a triple degP-degQ-degS mutant. All the deg deletions were transduced into the mouse-virulent strain SL1344 and the resultant mutants were injected intravenously into BALB/c mice to test virulence. degP and degS single mutants and all combinations of double and triple mutants were attenuated to different degrees, whereas the single degQ mutant was as virulent as the wild-type strain. Thus, within this gene family, degP and degS appear important for survival at elevated temperature and are necessary for full virulence, whereas a single degQ deletion appears to have no clear role in survival and growth at elevated temperature or in mice.
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Affiliation(s)
- Elaine Mo
- Wolfson Institute for Biomedical Research, University College London, Cruciform Building, Gower Street, London WC1E 6BT, UK.
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49
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Abstract
The sigma E regulon encodes proteins for maintenance and repair of the Escherichia coli cell envelope. Previously, we observed that an antirepressor of sigma E, DegS, is essential for uropathogenic E. coli virulence. Here we use a mouse urinary tract infection model to assay the virulence of mutants of E. coli genes described as sigma E dependent. Deletion mutants of candidate genes were made in the uropathogenic E. coli strain CFT073. Swiss Webster female mice were inoculated with a mixture of mutant and wild-type strains. Bladder and kidney homogenates were cultured 2 days after infection, and CFU of the wild type and mutant were compared. Eleven mutants were assayed, and two, CFT073 degP and CFT073 skp, showed significantly diminished survival compared to wild type. DegP is a chaperone and degradase active in the periplasm. Skp is also a periplasmic chaperone. The virulence of the skp deletion mutant could not be restored by complementation with skp. The virulence of the degP deletion mutant, in contrast, could be restored. However, complementation with a degP allele encoding a serine-to-alanine (S210A) mutation at the protease active site fails to restore virulence. Unlike degP mutants in other bacteria, the E. coli degP mutant is tolerant of oxidative stress. It disappears abruptly from bladder and kidney cultures between 6 and 12 hours after inoculation. A mutant of degQ, a close homolog of degP, was not attenuated in mice. This is the first report that the DegP degradase is an E. coli virulence factor in an animal infection model.
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Affiliation(s)
- Peter Redford
- Dept. of Medical Microbiology & Immunology, Rm. 481 MSB, 1300 University Ave., Madison, WI 53706-1532, USA
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Rowley G, Spector M, Kormanec J, Roberts M. Pushing the envelope: extracytoplasmic stress responses in bacterial pathogens. Nat Rev Microbiol 2006; 4:383-94. [PMID: 16715050 DOI: 10.1038/nrmicro1394] [Citation(s) in RCA: 245] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Despite being nutrient rich, the tissues and fluids of vertebrates are hostile to microorganisms, and most bacteria that attempt to take advantage of this environment are rapidly eliminated by host defences. Pathogens have evolved various means to promote their survival in host tissues, including stress responses that enable bacteria to sense and adapt to adverse conditions. Many different stress responses have been described, some of which are responsive to one or a small number of cues, whereas others are activated by a broad range of insults. The surface layers of pathogenic bacteria directly interface with the host and can bear the brunt of the attack by the host armoury. Several stress systems that respond to perturbations in the microbial cell outside of the cytoplasm have been described and are known collectively as extracytoplasmic or envelope stress responses (ESRs). Here, we review the role of the ESRs in the pathogenesis of Gram-negative bacterial pathogens.
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Affiliation(s)
- Gary Rowley
- Molecular Bacteriology Group, Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
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