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Tweedie A, Nissan T. Hiding in Plain Sight: Formation and Function of Stress Granules During Microbial Infection of Mammalian Cells. Front Mol Biosci 2021; 8:647884. [PMID: 33996904 PMCID: PMC8116797 DOI: 10.3389/fmolb.2021.647884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/01/2021] [Indexed: 01/21/2023] Open
Abstract
Stress granule (SG) formation is a host cell response to stress-induced translational repression. SGs assemble with RNA-binding proteins and translationally silent mRNA. SGs have been demonstrated to be both inhibitory to viruses, as well as being subverted for viral roles. In contrast, the function of SGs during non-viral microbial infections remains largely unexplored. A handful of microbial infections have been shown to result in host SG assembly. Nevertheless, a large body of evidence suggests SG formation in hosts is a widespread response to microbial infection. Diverse stresses caused by microbes and their products can activate the integrated stress response in order to inhibit translation initiation through phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α). This translational response in other contexts results in SG assembly, suggesting that SG assembly can be a general phenomenon during microbial infection. This review explores evidence for host SG formation in response to bacterial, fungal, and protozoan infection and potential functions of SGs in the host and for adaptations of the pathogen.
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Affiliation(s)
- Alistair Tweedie
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Tracy Nissan
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom.,Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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2
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Banerji R, Saroj SD. Early growth response 1 (EGR1) activation in initial stages of host-pathogen interactions. Mol Biol Rep 2021; 48:2935-2943. [PMID: 33783681 DOI: 10.1007/s11033-021-06305-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/19/2021] [Indexed: 12/11/2022]
Abstract
The factors that determine the outcomes of host-pathogen interactions, such as host specificity, tissue specificity, and transition from asymptomatic to symptomatic behavior of a pathogen, are yet to be deciphered. The initial interaction of a pathogen with host and host-associated factors play a crucial role in deciding such outcomes. One of the several host-factors that contribute to bacterial adhesion and the outcome of an infection is the activation of early growth response 1 (EGR1). EGR1 is an initial response transcriptional regulator that plays a vital role in regulating cell growth, differentiation, and survival. EGR1 expression is seen in most of the mammalian tissues. Multiple post-translational modifications occur, which modulate the EGR1 transcriptional activity. Upon activation, EGR1 can transactivate several genes with diverse cellular functions, including transcriptional regulatory proteins and cell proliferation. EGR1 has also been identified as a potential mediator of inflammatory gene expression. Recent studies have highlighted the role of EGR1 as a potent signaling molecule that facilitates bacterial adhesion to host epithelial cells, thus modulating colonization pathways. The pathways for the regulation of EGR1 during host-pathogen interaction remain yet unidentified. The review focuses on the role and regulation of EGR1 during host-pathogen interaction.
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Affiliation(s)
- Rajashri Banerji
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Symbiosis Knowledge Village, Lavale, Pune, Maharashtra, 412115, India
| | - Sunil D Saroj
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Symbiosis Knowledge Village, Lavale, Pune, Maharashtra, 412115, India.
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3
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Negretti NM, Gourley CR, Talukdar PK, Clair G, Klappenbach CM, Lauritsen CJ, Adkins JN, Konkel ME. The Campylobacter jejuni CiaD effector co-opts the host cell protein IQGAP1 to promote cell entry. Nat Commun 2021; 12:1339. [PMID: 33637714 PMCID: PMC7910587 DOI: 10.1038/s41467-021-21579-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 01/27/2021] [Indexed: 02/07/2023] Open
Abstract
Campylobacter jejuni is a foodborne pathogen that binds to and invades the epithelial cells lining the human intestinal tract. Maximal invasion of host cells by C. jejuni requires cell binding as well as delivery of the Cia proteins (Campylobacter invasion antigens) to the host cell cytosol via the flagellum. Here, we show that CiaD binds to the host cell protein IQGAP1 (a Ras GTPase-activating-like protein), thus displacing RacGAP1 from the IQGAP1 complex. This, in turn, leads to the unconstrained activity of the small GTPase Rac1, which is known to have roles in actin reorganization and internalization of C. jejuni. Our results represent the identification of a host cell protein targeted by a flagellar secreted effector protein and demonstrate that C. jejuni-stimulated Rac signaling is dependent on IQGAP1.
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Affiliation(s)
- Nicholas M Negretti
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Christopher R Gourley
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Prabhat K Talukdar
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Geremy Clair
- Integrative Omics, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Courtney M Klappenbach
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Cody J Lauritsen
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA
| | - Joshua N Adkins
- Integrative Omics, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Michael E Konkel
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, USA.
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4
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Abstract
Campylobacter jejuni and Campylobacter coli can be frequently isolated from poultry and poultry-derived products, and in combination these two species cause a large portion of human bacterial gastroenteritis cases. While birds are typically colonized by these Campylobacter species without clinical symptoms, in humans they cause (foodborne) infections at high frequencies, estimated to cost billions of dollars worldwide every year. The clinical outcome of Campylobacter infections comprises malaise, diarrhea, abdominal pain and fever. Symptoms may continue for up to two weeks and are generally self-limiting, though occasionally the disease can be more severe or result in post-infection sequelae. The virulence properties of these pathogens have been best-characterized for C. jejuni, and their actions are reviewed here. Various virulence-associated bacterial determinants include the flagellum, numerous flagellar secreted factors, protein adhesins, cytolethal distending toxin (CDT), lipooligosaccharide (LOS), serine protease HtrA and others. These factors are involved in several pathogenicity-linked properties that can be divided into bacterial chemotaxis, motility, attachment, invasion, survival, cellular transmigration and spread to deeper tissue. All of these steps require intimate interactions between bacteria and host cells (including immune cells), enabled by the collection of bacterial and host factors that have already been identified. The assortment of pathogenicity-associated factors now recognized for C. jejuni, their function and the proposed host cell factors that are involved in crucial steps leading to disease are discussed in detail.
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5
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Olotu C, Lehmensiek F, Koch B, Kiefmann M, Riegel AK, Hammerschmidt S, Kiefmann R. Streptococcus pneumoniae inhibits purinergic signaling and promotes purinergic receptor P2Y 2 internalization in alveolar epithelial cells. J Biol Chem 2019; 294:12795-12806. [PMID: 31289122 DOI: 10.1074/jbc.ra118.007236] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 06/28/2019] [Indexed: 12/14/2022] Open
Abstract
Bacterial pneumonia is a global health challenge that causes up to 2 million deaths each year. Purinergic signaling plays a pivotal role in healthy alveolar epithelium. Here, we used fluorophore-based analysis and live-cell calcium imaging to address the question of whether the bacterial pathogen Streptococcus pneumoniae directly interferes with purinergic signaling in alveolar epithelial cells. Disturbed purinergic signaling might result in pathophysiologic changes like edema formation and atelectasis, which are commonly seen in bacterial pneumonia. Purine receptors are mainly activated by ATP, mediating a cytosolic calcium response. We found that this purinergic receptor P2Y2-mediated response is suppressed in the presence of S. pneumoniae in A549 and isolated primary alveolar cells in a temperature-dependent manner. Downstream inositol 3-phosphate (IP3) signaling appeared to be unaffected, as calcium signaling via protease-activated receptor 2 remained unaltered. S. pneumoniae-induced suppression of the P2Y2-mediated calcium response depended on the P2Y2 phosphorylation sites Ser-243, Thr-344, and Ser-356, which are involved in receptor desensitization and internalization. Spinning-disk live-cell imaging revealed that S. pneumoniae induces P2Y2 translocation into the cytosol. In conclusion, our results show that S. pneumoniae directly inhibits purinergic signaling by inducing P2Y2 phosphorylation and internalization, resulting in the suppression of the calcium response of alveolar epithelial cells to ATP, thereby affecting cellular integrity and function.
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Affiliation(s)
- Cynthia Olotu
- Center for Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 22051 Hamburg, Germany
| | - Felix Lehmensiek
- Center for Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 22051 Hamburg, Germany
| | - Bastian Koch
- Center for Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 22051 Hamburg, Germany
| | - Martina Kiefmann
- Center for Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 22051 Hamburg, Germany
| | - Ann-Kathrin Riegel
- Center for Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 22051 Hamburg, Germany
| | - Sven Hammerschmidt
- Institute of Genetics and Functional Genomics, Department of Molecular Genetics and Infection Biology, University of Greifswald, Felix-Hausdorff-Strasse 8, 17489 Greifswald, Germany
| | - Rainer Kiefmann
- Center for Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 22051 Hamburg, Germany
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6
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He H, Arsenault RJ, Genovese KJ, Swaggerty CL, Johnson C, Nisbet DJ, Kogut MH. Inhibition of calmodulin increases intracellular survival of Salmonella in chicken macrophage cells. Vet Microbiol 2019; 232:156-161. [PMID: 30967327 DOI: 10.1016/j.vetmic.2019.02.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/01/2019] [Accepted: 02/05/2019] [Indexed: 01/05/2023]
Abstract
Calcium (Ca2+) is a pivotal intracellular second messenger and calmodulin (CaM) acts as a multifunctional Ca2+-binding protein that regulates downstream Ca2+ dependent signaling. Together they play an important role in regulating various cellular functions, including gene expression, maturation of phagolysosome, apoptosis, and immune response. Intracellular Ca2+ has been shown to play a critical role in Toll-like receptor-mediated immune response to microbial agonists in the HD11 chicken macrophage cell line. The role of that the Ca2+/CaM pathway plays in the intracellular survival of Salmonella in chicken macrophages has not been reported. In this study, kinome peptide array analysis indicated that the Ca2+/CaM pathway was significantly activated when chicken macrophage HD11 cells were infected with S. Enteritidis or S. Heidelberg. Further study demonstrated that treating cells with a pharmaceutical CaM inhibitor W-7, which disrupts the formation of Ca2+/CaM, significantly inhibited macrophages to produce nitric oxide and weaken the control of intracellular Salmonella replication. These results strongly indicate that CaM plays an important role in the innate immune response of chicken macrophages and that the Ca2+/CaM mediated signaling pathway is critically involved in the host cell response to Salmonella infection.
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Affiliation(s)
- Haiqi He
- Southern Plains Agricultural Research Center, USDA-ARS, College Station, TX 77845, United States.
| | - Ryan J Arsenault
- Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716, United States
| | - Kenneth J Genovese
- Southern Plains Agricultural Research Center, USDA-ARS, College Station, TX 77845, United States
| | - Christina L Swaggerty
- Southern Plains Agricultural Research Center, USDA-ARS, College Station, TX 77845, United States
| | - Casey Johnson
- Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716, United States
| | - David J Nisbet
- Southern Plains Agricultural Research Center, USDA-ARS, College Station, TX 77845, United States
| | - Michael H Kogut
- Southern Plains Agricultural Research Center, USDA-ARS, College Station, TX 77845, United States
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Host cellular unfolded protein response signaling regulates Campylobacter jejuni invasion. PLoS One 2018; 13:e0205865. [PMID: 30321237 PMCID: PMC6188877 DOI: 10.1371/journal.pone.0205865] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/02/2018] [Indexed: 12/20/2022] Open
Abstract
Campylobacter jejuni is a major cause of bacterial foodborne illness in humans worldwide. Bacterial entry into a host eukaryotic cell involves the initial steps of adherence and invasion, which generally activate several cell-signaling pathways that induce the activation of innate defense systems, which leads to the release of proinflammatory cytokines and induction of apoptosis. Recent studies have reported that the unfolded protein response (UPR), a system to clear unfolded proteins from the endoplasmic reticulum (ER), also participates in the activation of cellular defense mechanisms in response to bacterial infection. However, no study has yet investigated the role of UPR in C. jejuni infection. Hence, the aim of this study was to deduce the role of UPR signaling via induction of ER stress in the process of C. jejuni infection. The results suggest that C. jejuni infection suppresses global protein translation. Also, 12 h of C. jejuni infection induced activation of the eIF2α pathway and expression of the transcription factor CHOP. Interestingly, bacterial invasion was facilitated by knockdown of UPR-associated signaling factors and treatment with the ER stress inducers, thapsigargin and tunicamycin, decreased the invasive ability of C. jejuni. An investigation into the mechanism of UPR-mediated inhibition of C. jejuni invasion showed that UPR signaling did not affect bacterial adhesion to or survival in the host cells. Further, Salmonella Enteritidis or FITC-dextran intake were not regulated by UPR signaling. These results indicated that the effect of UPR on intracellular intake was specifically found in C. jejuni infection. These findings are the first to describe the role of UPR in C. jejuni infection and revealed the participation of a new signaling pathway in C. jejuni invasion. UPR signaling is involved in defense against the early step of C. jejuni invasion and thus presents a potential therapeutic target for the treatment of C. jejuni infection.
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8
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Casinhas J, Matos RG, Haddad N, Arraiano CM. Biochemical characterization of Campylobacter jejuni PNPase, an exoribonuclease important for bacterial pathogenicity. Biochimie 2018; 147:70-79. [PMID: 29339148 DOI: 10.1016/j.biochi.2018.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 01/11/2018] [Indexed: 10/18/2022]
Abstract
Bacteria need to promptly respond to environmental changes. Ribonucleases (RNases) are key factors in the adaptation to new environments by enabling a rapid adjustment in RNA levels. The exoribonuclease polynucleotide phosphorylase (PNPase) is essential for low-temperature cell survival, affects the synthesis of proteins involved in virulence and has an important role in swimming, cell adhesion/invasion ability, and chick colonization in C. jejuni. However, the mechanism of action of this ribonuclease is not yet known. In this work we have characterized the biochemical activity of C. jejuni PNPase. Our results demonstrate that Cj-PNP is a processive 3' to 5' exoribonuclease that degrades single-stranded RNAs. Its activity is regulated according to the temperature and divalent ions. We have also shown that the KH and S1 domains are important for trimerization, RNA binding, and, consequently, for the activity of Cj-PNP. These findings will be helpful to develop new strategies for fighting against C. jejuni and may be extrapolated to other foodborne pathogens.
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Affiliation(s)
- Jorge Casinhas
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Ava da República, 2780-157, Oeiras, Portugal.
| | - Rute G Matos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Ava da República, 2780-157, Oeiras, Portugal.
| | - Nabila Haddad
- SECALIM, INRA, Oniris, Université Bretagne Loire, 44307, Nantes, France.
| | - Cecília M Arraiano
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Ava da República, 2780-157, Oeiras, Portugal.
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9
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Chen R, Ji G, Ma T, Huang X, Ren H, Xi L. Role of intracellular free calcium in killing Penicillium marneffei within human macrophages. Microb Pathog 2015; 83-84:29-34. [PMID: 25959526 DOI: 10.1016/j.micpath.2015.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 05/04/2015] [Accepted: 05/06/2015] [Indexed: 12/01/2022]
Abstract
Increases in cytosolic Ca(2+) concentration ([Ca(2+)]c) promote phagocyte antimicrobial responses. Here, we investigated macrophages stimulated by Penicillium marneffei (P. marneffei). [Ca(2+)]c was determined in macrophages loaded with the fluorescent calcium probe Fura 2/AM as they were stimulated by P. marneffei. We found that P. marneffei induced an increase in [Ca(2+)]c in human macrophages. Further, increased [Ca(2+)]c with the ionophore A23187 promoted phagosomal acidification and maturation and reduced intracellular replication of P. marneffei in P. marneffei-infected human macrophages, whereas decreased [Ca(2+)]c with the chelation MAPTAM decreased TNF-α production, inhibited phagosomal acidification and maturation and increased intracellular replication of P. marneffei. These data indicate that Ca(2+) signaling may play an important role in controlling the replication of P. marneffei within macrophages.
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Affiliation(s)
- Renqiong Chen
- Department of Dermatology, Lianyungang First People's Hospital, Lianyungang 222002, China
| | - Guangquan Ji
- Department of Dermatology, Lianyungang First People's Hospital, Lianyungang 222002, China
| | - Tuan Ma
- Department of Dermatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Xiaowen Huang
- Department of Dermatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Hong Ren
- Department of Dermatology, Lianyungang First People's Hospital, Lianyungang 222002, China
| | - Liyan Xi
- Department of Dermatology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.
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Vibrio vulnificus RtxA1 modulated calcium flux contributes reduced internalization in phagocytes. Life Sci 2015; 132:55-60. [PMID: 25916802 DOI: 10.1016/j.lfs.2015.03.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 03/05/2015] [Accepted: 03/25/2015] [Indexed: 12/17/2022]
Abstract
AIMS Vibrio vulnificusis an opportunistic pathogen that causes primary septicemia and wound infection with high mortality rate. This pathogen produces an RTX toxin (RtxA1) which can cause host cell rounding, cell death and interference with internalization by host phagocytes. However, the mechanism of RtxA1-induced phagocyte paralysis is not clear. MAIN METHODS Using the murine macrophage cell line RAW264.7, we measured cytotoxicity and phagocytosis of V. vulnificusin normal and calcium-depleted media. To deplete extracellular and cytosolic Ca(2+), cells were exposed to the calcium chelators ethylene glycol tetraacetic acid (EGTA) and 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid, tetraacetoxymethyl esteris (BAPTA-AM), respectively. The cytotoxicity was examined by measuring the activity of lactate dehydrogenase (LDH) released from the damaged cells. The gentamicin protection assay was conducted to determine the number of internalized bacteria, while acridine orange staining was applied to visualize the intracellular bacteria. The fluorescent indicator fura-2-acetoxymethyl ester (fura 2-AM) was used to measure the Ca(2+)signal post-infection. KEY FINDINGS We revealed that extracellular Ca(2+)was essential for phagocytes to internalize V. vulnificus. Meanwhile, cytosolic Ca(2+)flux in RAW264.7 cells induced by an RtxA1 isogenic mutant was repressed by the parent strain. Furthermore, depletion of extracellular Ca(2+)level by EGTA significantly reduced the cytotoxicity but did not affect the antiphagocytic activity of RtxA1 toxin. SIGNIFICANCE Our results indicated that RtxA1 may interfere with cytosolic Ca(2+)flux of phagocyte to promote bacteria colonization.
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Awad WA, Smorodchenko A, Hess C, Aschenbach JR, Molnár A, Dublecz K, Khayal B, Pohl EE, Hess M. Increased intracellular calcium level and impaired nutrient absorption are important pathogenicity traits in the chicken intestinal epithelium during Campylobacter jejuni colonization. Appl Microbiol Biotechnol 2015; 99:6431-41. [PMID: 25825050 DOI: 10.1007/s00253-015-6543-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 03/09/2015] [Accepted: 03/11/2015] [Indexed: 02/08/2023]
Abstract
Although a high number of chickens carry Campylobacter jejuni, the mechanistic action of colonization in the intestine is still poorly understood. The current study was therefore designed to investigate the effects of C. jejuni on glucose uptake, amino acids availability in digesta, and intracellular calcium [Ca(2+)]i signaling in the intestines of broiler chickens. For this, we compared: control birds (n = 60) and C. jejuni-infected birds (n = 60; infected orally with 1 × 10(8) CFU of C. jejuni NCTC 12744 at 14 days of age). Our results showed that glucose uptake was reduced due to C. jejuni infection in isolated jejunal, but not in cecal mucosa at 14 days postinfection (dpi). The decrease in intestinal glucose absorption coincided with a decrease in body weight gain during the 2-week post-infectious period. A reduction in the amount of the amino acids (serine, proline, valine, leucine, phenylalanine, arginine, histidine, and lysine) in ileal digesta of the infected birds at 2 and/or 7 dpi was found, indicating that Campylobacter utilizes amino acids as a carbon source for their multiplication. Applying the cell-permeable Ca(2+) indicator Fluo-4 and two-photon microscopy, we revealed that [Ca(2+)]i was increased in the jejunal and cecal mucosa of infected birds. The muscarinic agonist carbachol induced an increase in [Ca(2+)]i in jejunum and cecum mucosa of control chickens, a response absent in the mucosa of infected chickens, demonstrating that the modulation of [Ca(2+)]i by Campylobacter might be involved in facilitating the necessary cytoskeletal rearrangements that occur during the bacterial invasion of epithelial cells. In conclusion, this study demonstrates the multifaceted interactions of C. jejuni with the gastrointestinal mucosa of broiler chickens. For the first time, it could be shown that a Campylobacter infection could interfere with intracellular Ca(2+) signaling and nutrient absorption in the small intestine with consequences on intestinal function, performance, and Campylobacter colonization. Altogether, these findings indicate that Campylobacter is not entirely a commensal and can be recognized as an important factor contributing to an impaired chicken gut health.
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Affiliation(s)
- Wageha A Awad
- Clinic for Poultry and Fish Medicine, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna, Austria,
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12
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Asmat TM, Tenenbaum T, Jonsson AB, Schwerk C, Schroten H. Impact of calcium signaling during infection of Neisseria meningitidis to human brain microvascular endothelial cells. PLoS One 2014; 9:e114474. [PMID: 25464500 PMCID: PMC4252121 DOI: 10.1371/journal.pone.0114474] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 11/10/2014] [Indexed: 01/08/2023] Open
Abstract
The pili and outer membrane proteins of Neisseria meningitidis (meningococci) facilitate bacterial adhesion and invasion into host cells. In this context expression of meningococcal PilC1 protein has been reported to play a crucial role. Intracellular calcium mobilization has been implicated as an important signaling event during internalization of several bacterial pathogens. Here we employed time lapse calcium-imaging and demonstrated that PilC1 of meningococci triggered a significant increase in cytoplasmic calcium in human brain microvascular endothelial cells, whereas PilC1-deficient meningococci could not initiate this signaling process. The increase in cytosolic calcium in response to PilC1-expressing meningococci was due to efflux of calcium from host intracellular stores as demonstrated by using 2-APB, which inhibits the release of calcium from the endoplasmic reticulum. Moreover, pre-treatment of host cells with U73122 (phospholipase C inhibitor) abolished the cytosolic calcium increase caused by PilC1-expressing meningococci demonstrating that active phospholipase C (PLC) is required to induce calcium transients in host cells. Furthermore, the role of cytosolic calcium on meningococcal adherence and internalization was documented by gentamicin protection assay and double immunofluorescence (DIF) staining. Results indicated that chelation of intracellular calcium by using BAPTA-AM significantly impaired PilC1-mediated meningococcal adherence to and invasion into host endothelial cells. However, buffering of extracellular calcium by BAPTA or EGTA demonstrated no significant effect on meningococcal adherence to and invasion into host cells. Taken together, these results indicate that meningococci induce calcium release from intracellular stores of host endothelial cells via PilC1 and cytoplasmic calcium concentrations play a critical role during PilC1 mediated meningococcal adherence to and subsequent invasion into host endothelial cells.
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Affiliation(s)
- Tauseef M. Asmat
- Department of Pediatrics, Pediatric Infectious Diseases, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- * E-mail:
| | - Tobias Tenenbaum
- Department of Pediatrics, Pediatric Infectious Diseases, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Ann-Beth Jonsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Christian Schwerk
- Department of Pediatrics, Pediatric Infectious Diseases, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Horst Schroten
- Department of Pediatrics, Pediatric Infectious Diseases, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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13
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Sarjit A, Wang Y, Dykes GA. Antimicrobial activity of gallic acid against thermophilic Campylobacter is strain specific and associated with a loss of calcium ions. Food Microbiol 2014; 46:227-233. [PMID: 25475290 DOI: 10.1016/j.fm.2014.08.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 07/27/2014] [Accepted: 08/11/2014] [Indexed: 11/16/2022]
Abstract
Gallic acid has been suggested as a potential antimicrobial for the control of Campylobacter but its effectiveness is poorly studied. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of gallic acid against Campylobacter jejuni (n = 8) and Campylobacter coli (n = 4) strains was determined. Gallic acid inhibited the growth of five C. jejuni strains and three C. coli strains (MIC: 15.63-250 μg mL(-1)). Gallic acid was only bactericidal to two C. coli strains (MBC: 125 and 62.5 μg mL(-1)). The mechanism of the bactericidal effect against these two strains (and selected non-susceptible controls) was investigated by determining decimal reduction times and by monitoring the loss of cellular content and calcium ions, and changes in cell morphology. Gallic acid did not result in a loss of cellular content or morphological changes in the susceptible strains as compared to the controls. Gallic acid resulted in a loss of calcium ions (0.58-1.53 μg mL(-1) and 0.54-1.17 μg mL(-1), respectively, over a 180 min period) from the susceptible strains but not the controls. Gallic acid is unlikely to be an effective antimicrobial against Campylobacter in a practical sense unless further interventions to ensure an effective bactericidal mode of action against all strains are developed.
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Affiliation(s)
- Amreeta Sarjit
- School of Science, Monash University, Jalan Lagoon Selatan, Bandar Sunway, 46150, Selangor, Malaysia
| | - Yi Wang
- School of Science, Monash University, Jalan Lagoon Selatan, Bandar Sunway, 46150, Selangor, Malaysia
| | - Gary A Dykes
- School of Science, Monash University, Jalan Lagoon Selatan, Bandar Sunway, 46150, Selangor, Malaysia.
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The involvement of FAK and Src in the invasion of cardiomyocytes by Trypanosoma cruzi. Exp Parasitol 2014; 139:49-57. [PMID: 24582948 DOI: 10.1016/j.exppara.2014.02.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 12/10/2013] [Accepted: 02/05/2014] [Indexed: 11/20/2022]
Abstract
The activation of signaling pathways involving protein tyrosine kinases (PTKs) has been demonstrated during Trypanosoma cruzi invasion. Herein, we describe the participation of FAK/Src in the invasion of cardiomyocytes by T. cruzi. The treatment of cardiomyocytes with genistein, a PTK inhibitor, significantly reduced T. cruzi invasion. Also, PP1, a potent Src-family protein inhibitor, and PF573228, a specific FAK inhibitor, also inhibited T. cruzi entry; maximal inhibition was achieved at concentrations of 25μM PP1 (53% inhibition) and 40μM PF573228 (50% inhibition). The suppression of FAK expression in siRNA-treated cells and tetracycline-uninduced Tet-FAK(WT)-46 cells significantly reduced T. cruzi invasion. The entry of T. cruzi is accompanied by changes in FAK and c-Src expression and phosphorylation. An enhancement of FAK activation occurs during the initial stages of T. cruzi-cardiomyocyte interaction (30 and 60min), with a concomitant increase in the level of c-Src expression and phosphorylation, suggesting that FAK/Src act as an integrated signaling pathway that coordinates parasite entry. These data provide novel insights into the signaling pathways that are involved in cardiomyocyte invasion by T. cruzi. A better understanding of the signal transduction networks involved in T. cruzi invasion may contribute to the development of more effective therapies for the treatment of Chagas' disease.
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Zhao JF, Chen HH, Ojcius DM, Zhao X, Sun D, Ge YM, Zheng LL, Lin X, Li LJ, Yan J. Identification of Leptospira interrogans phospholipase C as a novel virulence factor responsible for intracellular free calcium ion elevation during macrophage death. PLoS One 2013; 8:e75652. [PMID: 24124502 PMCID: PMC3790881 DOI: 10.1371/journal.pone.0075652] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 08/17/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Leptospira-induced macrophage death has been confirmed to play a crucial role in pathogenesis of leptospirosis, a worldwide zoonotic infectious disease. Intracellular free Ca(2+) concentration ([Ca(2+)]i) elevation induced by infection can cause cell death, but [Ca(2+)]i changes and high [Ca(2+)]i-induced death of macrophages due to infection of Leptospira have not been previously reported. METHODOLOGY/PRINCIPAL FINDINGS We first used a Ca(2+)-specific fluorescence probe to confirm that the infection of L. interrogans strain Lai triggered a significant increase of [Ca(2+)]i in mouse J774A.1 or human THP-1 macrophages. Laser confocal microscopic examination showed that the [Ca(2+)]i elevation was caused by both extracellular Ca(2+) influx through the purinergic receptor, P2X7, and Ca(2+) release from the endoplasmic reticulum, as seen by suppression of [Ca(2+)]i elevation when receptor-gated calcium channels were blocked or P2X7 was depleted. The LB361 gene product of the spirochete exhibited phosphatidylinositol phospholipase C (L-PI-PLC) activity to hydrolyze phosphatidylinositol-4,5-bisphosphate (PIP2) into inositol-1,4,5-trisphosphate (IP3), which in turn induces intracellular Ca(2+) release from endoplasmic reticulum, with the Km of 199 µM and Kcat of 8.566E-5 S(-1). Secretion of L-PI-PLC from the spirochete into supernatants of leptospire-macrophage co-cultures and cytosol of infected macrophages was also observed by Western Blot assay. Lower [Ca(2+)]i elevation was induced by infection with a LB361-deficient leptospiral mutant, whereas transfection of the LB361 gene caused a mild increase in [Ca(2+)]i. Moreover, PI-PLCs (PI-PLC-β3 and PI-PLC-γ1) of the two macrophages were activated by phosphorylation during infection. Flow cytometric detection demonstrated that high [Ca(2+)]i increases induced apoptosis and necrosis of macrophages, while mild [Ca(2+)]i elevation only caused apoptosis. CONCLUSIONS/SIGNIFICANCE This study demonstrated that L. interrogans infection induced [Ca(2+)]i elevation through extracellular Ca(2+) influx and intracellular Ca(2+) release cause macrophage apoptosis and necrosis, and the LB361 gene product was shown to be a novel PI-PLC of L. interrogans responsible for the [Ca(2+)]i elevation.
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Affiliation(s)
- Jing-Fang Zhao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
- Depatment of Clinical Laboratory, Zhejiang Provincial Hospital of Traditional Chinese Medicine, Hangzhou, Zhejiang, P.R. China
| | - Hong-Hu Chen
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - David M. Ojcius
- Health Sciences Research Institute and Department Molecular Cell Biology, University of California Merced, Merced, California, United States of America
| | - Xin Zhao
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Dexter Sun
- Department of Neurology and Neuroscience, New York Presbyterian Hospital and Hospital for Special Surgery, Cornell University Weill Medical College, New York, New York, United States of America
| | - Yu-Mei Ge
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Lin-Li Zheng
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Xu’ai Lin
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Lan-Juan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
| | - Jie Yan
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
- Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, P.R. China
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Molecular methods to investigate adhesion, transmigration, invasion and intracellular survival of the foodborne pathogen Campylobacter jejuni. J Microbiol Methods 2013; 95:8-23. [DOI: 10.1016/j.mimet.2013.06.031] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 06/18/2013] [Accepted: 06/28/2013] [Indexed: 01/08/2023]
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Genome-wide association analysis of avian resistance to Campylobacter jejuni colonization identifies risk locus spanning the CDH13 gene. G3-GENES GENOMES GENETICS 2013; 3:881-90. [PMID: 23550144 PMCID: PMC3656734 DOI: 10.1534/g3.113.006031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The enteropathogen Campylobacter jejuni is a major worldwide health and economic burden, being one of the leading causes of bacterial gastroenteritis and commonly linked to postinfectious onset of autoimmune disease. Chickens are a major vector for human infection and even though variation in avian colonization level is heritable, no previous studies have identified regions of the genome associated with colonization resistance. We performed a genome-wide association study of resistance to C. jejuni colonization in the avian intestine by controlling for population structure, which revealed a risk locus with genome-wide significance spanning the T-cadherin (CDH13) gene. A second possible risk locus was also identified close to calmodulin (CALM1), a calcium-activated modulator of cadherin function. In addition, gene expression analysis of mRNA sequencing profiles revealed that the relative expression of the two genes is significantly associated with colonization resistance. Functional studies have previously demonstrated involvement of cadherins and calmodulin in C. jejuni intracellular invasion and colonization of human intestinal epithelial cells in vitro. Consistent with this finding, our analysis reveals that variation surrounding these genes is associated with avian colonization resistance in vivo and highlights their potential as possible targets for control of the bacterium in avian and human populations.
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Smani Y, Docobo-Pérez F, López-Rojas R, Domínguez-Herrera J, Ibáñez-Martínez J, Pachón J. Platelet-activating factor receptor initiates contact of Acinetobacter baumannii expressing phosphorylcholine with host cells. J Biol Chem 2012; 287:26901-10. [PMID: 22689572 DOI: 10.1074/jbc.m112.344556] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Adhesion is an initial and important step in Acinetobacter baumannii causing infections. However, the exact molecular mechanism of such a step between A. baumannii and the host cells remains unclear. Here, we demonstrated that the phosphorylcholine (ChoP)-containing outer membrane protein of A. baumannii binds to A549 cells through platelet-activating factor receptor (PAFR), resulting in activation of G protein and intracellular calcium. Upon A. baumannii expressing ChoP binding to PAFR, clathrin and β-arrestins, proteins involved in the direction of the vacuolar movement, are activated during invasion of A. baumannii. PAFR antagonism restricts the dissemination of A. baumannii in the pneumonia model. These results define a role for PAFR in A. baumannii interaction with host cells and suggest a mechanism for the entry of A. baumannii into the cytoplasm of host cells.
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Affiliation(s)
- Younes Smani
- Clinic Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain.
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19
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Konar M, Ghosh S. Enteroaggregative Escherichia coli induced increase in intracellular calcium concentration modulates cytoskeletal F-actin rearrangement and bacterial entry in INT-407 cells. Microb Pathog 2012; 52:278-84. [PMID: 22553831 DOI: 10.1016/j.micpath.2012.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Enteroaggregative Escherichia coli (EAEC) is an emerging enteric pathogen, associated with cases of acute and persistent diarrhoea worldwide. The pathogenesis of EAEC is yet to be understood. In intestinal epithelium, an increase in [Ca²⁺](i) has been attributed due to the action of different enteric pathogens. EAEC was shown to increase [Ca²⁺](i) in HEp-2 cells.The present study was undertaken to investigate the effect of EAEC induced increase in [Ca²⁺](i) oncultured human intestinal epithelial cells. METHODS INT-407 cells were infected with EAEC (T8 strain) in the absence and presence of dantrolene (inhibitor of release of Ca²⁺ from intracellular stores)/verapamil (L-type Ca²⁺ channel blocker)/BAPTAAM (Ca²⁺ chelator)/U73122 (PLC inhibitor)/Cytochalasin-D (inhibitor of actin polymerization). [Ca²⁺](i) was estimated using Fura-2/AM. Cytoskeletal rearrangement was assessed by F-actin staining using TRITC-phalloidin. The invasiveness of EAEC-T8 to INT-407 cells was checked by electron microscopy and invasion assay. RESULTS A significant increase in [Ca²⁺](i) was observed in EAEC-T8 infected INT-407 cells, which was reduced in presence of dantrolene/verapamil/U73122. EAEC-T8 could induce cytoskeletal F-actin polymerization in INT-407 cells and was found to be invasive in nature. The cytoskeletal rearrangement as well as invasion of EAEC-T8 was attenuated in presence of U73122/dantrolene/BAPTA-AM/verapamil/cytochalasin D. CONCLUSIONS EAEC induced increase in [Ca²⁺](i) seems to play a major role in host cytoskeletal F-actin rearrangements leading to invasion of the organism. GENERAL SIGNIFICANCE Our study undoubtedly will lead to an improved understanding of EAEC-pathogenesis.
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Affiliation(s)
- Monica Konar
- Department of Experimental Medicine & Biotechnology, Post Graduate Institute of Medical Education & Research, Chandigarh 160012, India
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20
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O Cróinín T, Backert S. Host epithelial cell invasion by Campylobacter jejuni: trigger or zipper mechanism? Front Cell Infect Microbiol 2012; 2:25. [PMID: 22919617 PMCID: PMC3417527 DOI: 10.3389/fcimb.2012.00025] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 02/17/2012] [Indexed: 11/18/2022] Open
Abstract
Campylobacter jejuni, a spiral-shaped Gram-negative pathogen, is a highly frequent cause of gastrointestinal foodborne illness in humans worldwide. Clinical outcome of C. jejuni infections ranges from mild to severe diarrheal disease, and some other complications including reactive arthritis and Guillain–Barré syndrome. This review article highlights various C. jejuni pathogenicity factors, host cell determinants, and proposed signaling mechanisms involved in human host cell invasion and their potential role in the development of C. jejuni-mediated disease. A model is presented which outlines the various important interactions of C. jejuni with the intestinal epithelium, and we discuss the pro’s and con’s for the “zipper” over the “trigger” mechanism of invasion. Future work should clarify the contradictory role of some previously identified factors, and should identify and characterize novel virulence determinants, which are crucial to provide fresh insights into the diversity of strategies employed by this pathogen to cause disease.
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Affiliation(s)
- Tadhg O Cróinín
- UCD School of Biomolecular and Biomedical Sciences, University College Dublin Dublin, Ireland
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21
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Ko Y, Cho NH, Cho BA, Kim IS, Choi MS. Involvement of Ca2+ signaling in intracellular invasion of non-phagocytic host cells by Orientia tsutsugamushi. Microb Pathog 2011; 50:326-30. [DOI: 10.1016/j.micpath.2011.02.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/15/2011] [Accepted: 02/21/2011] [Indexed: 10/18/2022]
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22
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Asmat TM, Agarwal V, Räth S, Hildebrandt JP, Hammerschmidt S. Streptococcus pneumoniae infection of host epithelial cells via polymeric immunoglobulin receptor transiently induces calcium release from intracellular stores. J Biol Chem 2011; 286:17861-9. [PMID: 21454571 DOI: 10.1074/jbc.m110.212225] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The pneumococcal surface protein C (PspC) is a major adhesin of Streptococcus pneumoniae (pneumococci) that interacts in a human-specific manner with the ectodomain of the human polymeric immunoglobulin receptor (pIgR) produced by respiratory epithelial cells. This interaction promotes bacterial colonization and bacterial internalization by initiating host signal transduction cascades. Here, we examined alterations of intracellular calcium ([Ca(2+)](i)) levels in epithelial cells during host cell infections with pneumococci via the PspC-hpIgR mechanism. The release of [Ca(2+)](i) from intracellular stores in host cells was significantly increased by wild-type pneumococci but not by PspC-deficient pneumococci. The increase in [Ca(2+)](i) was dependent on phospholipase C as pretreatment of cells with a phospholipase C-specific inhibitor U73122 abolished the increase in [Ca(2+)](i). In addition, we demonstrated the effect of [Ca(2+)](i) on pneumococcal internalization by epithelial cells. Uptake of pneumococci was significantly increased after pretreatment of epithelial cells with the cell-permeable calcium chelator 1,2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid-tetraacetoxymethyl ester or use of EGTA as an extracellular Ca(2+)-chelating agent. In contrast, thapsigargin, an inhibitor of endoplasmic reticulum Ca(2+)ATPase, which increases [Ca(2+)](i) in a sustained fashion, significantly reduced pIgR-mediated pneumococcal invasion. Importantly, pneumococcal adherence to pIgR-expressing cells was not altered in the presence of inhibitors as demonstrated by immunofluorescence microscopy. In conclusion, these results demonstrate that pneumococcal infections induce mobilization of [Ca(2+)](i) from intracellular stores. This may constitute a defense response of host cells as the experimental reduction of intracellular calcium levels facilitates pneumococcal internalization by pIgR-expressing cells, whereas elevated calcium levels diminished bacterial internalization by host epithelial cells.
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Affiliation(s)
- Tauseef M Asmat
- Department of Genetics of Microorganisms, Interfaculty Institute for Genetics and Functional Genomics, Ernst Moritz Arndt University of Greifswald, Friedrich-Ludwig-Jahn-Strasse 15a, D-17487 Greifswald, Germany
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23
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van Putten JPM, van Alphen LB, Wösten MMSM, de Zoete MR. Molecular mechanisms of campylobacter infection. Curr Top Microbiol Immunol 2010; 337:197-229. [PMID: 19812984 DOI: 10.1007/978-3-642-01846-6_7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Campylobacter jejuni is the principal bacterial foodborne pathogen. A major challenge still is to identify the virulence strategies exploited by C. jejuni. Recent genomics, proteomics, and metabolomics approaches indicate that C. jejuni displays extensive inter- and intrastrain variation. The diverse behavior enables bacterial adaptation to different environmental conditions and directs interactions with the gut mucosa. Here, we report recent progress in understanding the molecular mechanisms and functional consequences of the phenotype diversity. The results suggest that C. jejuni actively penetrates the intestinal mucus layer, secretes proteins mainly via its flagellar apparatus, is engulfed by intestinal cells, and can disrupt the integrity of the epithelial lining. C. jejuni stimulates the proinflammatory pathway and the production of a large repertoire of cytokines, chemokines, and innate effector molecules. Novel experimental infection models suggest that the activation of the innate immune response is important for the development of intestinal pathology.
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Affiliation(s)
- Jos P M van Putten
- Department of Infectious Diseases & Immunology, Utrecht University, Yalelaan 1, Utrecht, The Netherlands.
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24
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Lin C, Tsai P, Hung Y, Huang C. L-type calcium channels are involved in mediating the anti-inflammatory effects of magnesium sulphate. Br J Anaesth 2010; 104:44-51. [DOI: 10.1093/bja/aep336] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
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25
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Figueiredo JF, Barhoumi R, Raffatellu M, Lawhon SD, Rousseau B, Burghardt RC, Tsolis RM, Bäumler AJ, Adams LG. Salmonella enterica serovar Typhimurium-induced internalization and IL-8 expression in HeLa cells does not have a direct relationship with intracellular Ca(2+) levels. Microbes Infect 2009; 11:850-8. [PMID: 19450704 DOI: 10.1016/j.micinf.2009.05.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 05/02/2009] [Accepted: 05/04/2009] [Indexed: 10/20/2022]
Abstract
The invasion-associated type III secretion system (T3SS-1) of S. Typhimurium is required to initiate and sustain an acute inflammatory response in the intestine. We investigated the relationship of S. Typhimurium T3SS-1-induced IL-8 expression and invasion with intracellular Ca(2+) mobilization in HeLa cells. Compared to the sipAsopABDE2 mutant, strains carrying a mutation in sipA, or mutations in sopABDE2 induced higher levels of IL-8 and greater bacterial internalization despite the fact that these mutants elicited similarly low intracellular concentrations of Ca(2+). Likewise, complemented sipAsopABDE2 mutant with sopE2 did not affect intracellular Ca(2+) concentrations or IL-8 expression, but significantly increased bacterial internalization. Treating HeLa cells with the calcium chelator BAPTA-AM or with D-BAPTA-AM, a derivative with greatly reduced Ca(2+) chelating activity, yielded strong evidence that BAPTA-AM does not affect invasion and inhibits IL-8 secretion by a calcium-dependent mechanism. These findings suggest that, although wild-type S. Typhimurium-induced IL-8 expression and bacterial internalization in HeLa cells coincides with increased cytosolic Ca(2+), the differing levels of IL-8 and invasion induced by strains carrying different effector proteins are unrelated to levels of intracellular Ca(2+).
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Affiliation(s)
- Josely F Figueiredo
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4467, USA
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Bandyopadhaya A, Das D, Chaudhuri K. Involvement of intracellular signaling cascades in inflammatory responses in human intestinal epithelial cells following Vibrio cholerae infection. Mol Immunol 2008; 46:1129-39. [PMID: 19110311 DOI: 10.1016/j.molimm.2008.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Revised: 10/23/2008] [Accepted: 11/01/2008] [Indexed: 01/13/2023]
Abstract
Vibrio cholerae, the etiological agent of cholera, leads to the induction of host cell nuclear responses and the activation of proinflammatory cytokines in the cultured intestinal epithelial cells. However, the host cell signaling pathway leading to proinflammatory response is not explored. In this study, we demonstrated that V. cholerae infection on intestinal epithelial cells results in the activation of extracellular signal-regulated kinases1/2(ERK1/2) and p38 of the mitogen activated protein kinase (MAPK) family. V. cholerae induced intracellular pathways in Int407 cells leading to the activation of protein kinase A (PKA) and protein tyrosine kinase (PTK) in upstream of MAPK and nuclear factor-kappaB (NF-kappaB) pathway. Inhibitor study of Ca(2+) and phospholipase-gamma (PLC-gamma) pathway suggested the possible involvement of Ca(2+) signaling in the V. cholerae pathogenesis. V. cholerae culture supernatants as also insertional mutants of ctxA, toxR and toxT genes modulate the activation of MAPK and NF-kappaB signaling pathways. MAPK and NF-kappaB signaling pathway activation were also modulated by adherence and motility of V. cholerae. Studies with inhibitor of NF-kappaB, MAPK, PTK, PKA, PKC, Ca(2+) and PLC pathways showed differential cytokine secretion in Int407 following V. cholerae infection. Therefore V. cholerae mediated induction of nuclear responses through signal transduction pathway and subsequent activation of proinflammatory cytokines in Int407 modulated by V. cholerae secretory factors, virulence, adhesion/motility which might explain some of its reactogenic mechanisms.
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Affiliation(s)
- Arunava Bandyopadhaya
- Molecular and Human Genetics Division, Indian Institute of Chemical Biology (CSIR), 4 Raja S C Mullick Road, Kolkata 700032, India
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Enhanced microscopic definition of Campylobacter jejuni 81-176 adherence to, invasion of, translocation across, and exocytosis from polarized human intestinal Caco-2 cells. Infect Immun 2008; 76:5294-304. [PMID: 18765731 DOI: 10.1128/iai.01408-07] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Campylobacter jejuni-mediated pathogenesis involves gut adherence and translocation across intestinal cells. The current study was undertaken to examine the C. jejuni interaction with and translocation across differentiated Caco-2 cells to better understand Campylobacter's pathogenesis. The efficiency of C. jejuni 81-176 invasion of Caco-2 cells was two- to threefold less than the efficiency of invasion of INT407 cells. Adherence-invasion analyses indicated that C. jejuni 81-176 adhered to most INT407 cells but invaded only about two-thirds of the host cells over 2 h (two bacteria/cell). In contrast, only 11 to 17% of differentiated Caco-2 cells were observed to bind and internalize either C. jejuni strain 81-176 or NCTC 11168, and a small percentage of infected Caco-2 cells contained 5 to 20 internalized bacteria per cell after 2 h. Electron microscopy revealed that individual C. jejuni cells adhered to the tips of host cell microvilli via intimate flagellar contacts and by lateral bacterial binding to the sides of microvilli. Next, bacteria were observed to bind at the apical host membrane surface via presumed interactions at one pole of the bacterium and with host membrane protrusions located near intercellular junctions. The latter contacts apparently resulted in coordinated, localized plasma membrane invagination, causing simultaneous internalization of bacteria into an endosome. Passage of this Campylobacter endosome intracellularly from the apical surface to the basolateral surface occurred over time, and bacterial release apparently resulted from endosome-basolateral membrane fusion (i.e., exocytosis). Bacteria were found intercellularly below tight junctions at 60 min postinfection, but not at earlier times. This study revealed unique host cell adherence contacts, early endocytosis-specific structures, and a presumptive exocytosis component of the transcellular transcytosis route.
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Kim YV, Pearce D, Kim KS. Ca(2+)/calmodulin-dependent invasion of microvascular endothelial cells of human brain by Escherichia coli K1. Cell Tissue Res 2008; 332:427-33. [PMID: 18379824 DOI: 10.1007/s00441-008-0598-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Accepted: 02/04/2008] [Indexed: 12/24/2022]
Abstract
Escherichia coli K1 invasion of microvascular endothelial cells of human brain (HBMEC) is required for E. coli penetration into the central nervous system, but the microbial-host interactions that are involved in this invasion of HBMEC remain incompletely understood. We have previously shown that FimH, one of the E. coli determinants contributing to the binding to and invasion of HBMEC, induces Ca(2+) changes in HBMEC. In the present study, we have investigated in detail the role of cellular calcium signaling in the E. coli K1 invasion of HBMEC, the main constituents of the blood-brain barrier. Addition of the meningitis-causing E. coli K1 strain RS218 (O18:K1) to HBMEC results in transient increases of intracellular free Ca(2+). Inhibition of phospholipase C with U-73122 and the chelating of intracellular Ca(2+) by BAPTA/AM reduces bacterial invasion of HBMEC by approximately 50%. Blocking of transmembrane Ca(2+) fluxes by extracellular lanthanum ions also inhibits the E. coli invasion of HBMEC by approximately 50%. In addition, E. coli K1 invasion is significantly inhibited when HBMEC are pretreated by the calmodulin antagonists, trifluoperazine or calmidazolium, or by ML-7, a specific inhibitor of Ca(2+)/calmodulin-dependent myosin light-chain kinase. These findings indicate that host intracellular Ca(2+) signaling contributes in part to E. coli K1 invasion of HBMEC.
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Affiliation(s)
- Yuri V Kim
- Division of Pediatrics Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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van Alphen LB, Bleumink-Pluym NMC, Rochat KD, van Balkom BWM, Wösten MMSM, van Putten JPM. Active migration into the subcellular space precedes Campylobacter jejuni invasion of epithelial cells. Cell Microbiol 2008; 10:53-66. [PMID: 18052944 DOI: 10.1111/j.1462-5822.2007.01014.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The bacterial pathogen Campylobacter jejuni invades mucosal cells via largely undefined and rather inefficient (0.01-2 bacteria per cell) mechanisms. Here we report a novel, highly efficient C. jejuni infection pathway resulting in 10-15 intracellular bacteria per cell within 3 h of infection. Electron microscopy, pulse-chase infection assays and time-lapse multiphoton laser confocal microscopy demonstrated that the mechanism involved active and rapid migration of the pathogen into the subcellular space (termed 'subvasion'), followed by bacterial entry ('invasion') at the cell basis. Efficient subvasion was maximal after repeated rounds of selection for the subvasive phenotype. Targeted mutagenesis indicated that the CadF, JlpA or PEB1 adhesins were not required. Dissection of the selected and parental phenotypes by SDS-PAGE yielded comparable capsule polysaccharide and lipooligosaccharide profiles. Proteomics revealed reduced amounts of the chemotaxis protein CheW for the subvasive phenotype. Swarming assays confirmed that the selected phenotype exhibited altered migration behaviour. Introduction of a plasmid carrying chemotaxis genes into the subvasive strain yielded wild-type subvasion levels and migration behaviour. These results indicate that alterations in the bacterial migration machinery enable C. jejuni to actively penetrate the subcellular space and gain access to the cell interior with unprecedented efficiency.
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Affiliation(s)
- Lieke B van Alphen
- Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, The Netherlands
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Levin RE. Campylobacter jejuni: A Review of its Characteristics, Pathogenicity, Ecology, Distribution, Subspecies Characterization and Molecular Methods of Detection. FOOD BIOTECHNOL 2007. [DOI: 10.1080/08905430701536565] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Krause-Gruszczynska M, Rohde M, Hartig R, Genth H, Schmidt G, Keo T, König W, Miller WG, Konkel ME, Backert S. Role of the small Rho GTPases Rac1 and Cdc42 in host cell invasion of Campylobacter jejuni. Cell Microbiol 2007; 9:2431-44. [PMID: 17521326 DOI: 10.1111/j.1462-5822.2007.00971.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Host cell invasion of the food-borne pathogen Campylobacter jejuni is one of the primary reasons of tissue damage in humans but molecular mechanisms are widely unclear. Here, we show that C. jejuni triggers membrane ruffling in the eukaryotic cell followed by invasion in a very specific manner first with its tip followed by the flagellar end. To pinpoint important signalling events involved in the C. jejuni invasion process, we examined the role of small Rho family GTPases. Using specific GTPase-modifying toxins, inhibitors and GTPase expression constructs we show that Rac1 and Cdc42, but not RhoA, are involved in C. jejuni invasion. In agreement with these observations, we found that internalization of C. jejuni is accompanied by a time-dependent activation of both Rac1 and Cdc42. Finally, we show that the activation of these GTPases involves different host cell kinases and the bacterial fibronectin-binding protein CadF. Thus, CadF is a bifunctional protein which triggers bacterial binding to host cells as well as signalling leading to GTPase activation. Collectively, our results suggest that C. jejuni invade host target cells by a unique mechanism and the activation of the Rho GTPase members Rac1 and Cdc42 plays a crucial role in this entry process.
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Affiliation(s)
- Malgorzata Krause-Gruszczynska
- Department of Medical Microbiology, Otto von Guericke University Magdeburg, Leipziger Str. 44, D-39120 Magdeburg, Germany
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Hu L, McDaniel JP, Kopecko DJ. Signal transduction events involved in human epithelial cell invasion by Campylobacter jejuni 81-176. Microb Pathog 2006; 40:91-100. [PMID: 16426812 DOI: 10.1016/j.micpath.2005.11.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Revised: 11/14/2005] [Accepted: 11/14/2005] [Indexed: 11/26/2022]
Abstract
Analyses of invasive enteric bacteria (e.g. Shigella, Salmonella, Listeria, and Campylobacter) have shown that these pathogens initiate orchestrated signal transduction cascades in host cells leading to host cytoskeletal rearrangements that result in bacterial uptake. This current study was specifically aimed at examining the involvement of host membrane caveolae and certain protein kinases in epithelial cell invasion by C. jejuni strain 81-176, for which we have previously characterized the kinetics of entry and a unique microtubule-dependent mechanism of internalization. Utilizing in vitro cultured cell invasion assays with a gentamicin-kill step, disruption of membrane caveolae by pretreatment of INT407 cell monolayers with filipin III reduced C. jejuni 81-176 entry by >95%. Strain 81-176 uptake into INT407 cells was markedly inhibited by monolayer pretreatment with the protein kinase inhibitors genistein and staurosporine, or specific inhibitors of PI 3-kinase, wortmannin and LY294002. Western blot analysis using monoclonal anti-protein tyrosine phosphorylation antibody revealed distinctive changes during invasion in phosphorylation of at least nine proteins. Further inhibitor studies indicated that heterotrimeric G proteins, plus ERK and p38 MAP kinase activation are also involved in C. jejuni 81-176 invasion. These results suggest that C. jejuni 81-176 interact at host cell surface membrane caveolae with G protein-coupled receptors, which presumably trigger G-proteins and kinases to activate host proteins including PI 3-kinase and MAP kinases, that appear to be intimately involved in the events controlling 81-176 internalization.
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Affiliation(s)
- Lan Hu
- Laboratory of Enteric and Sexually Transmitted Diseases, Center for Biologics Evaluation and Research, FDA, NIH Campus Building 29/420, Bethesda, MD 20892, USA
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