51
|
Kneipp LF, Palmeira VF, Pinheiro AAS, Alviano CS, Rozental S, Travassos LR, Meyer-Fernandes JR. Phosphatase activity on the cell wall of Fonsecaea pedrosoi. Med Mycol 2004; 41:469-77. [PMID: 14725320 DOI: 10.1080/10683160310001615399] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The activity of a phosphatase was characterized in intact mycelial forms of Fonsecaea pedrosoi, a pathogenic fungus that causes chromoblastomycosis. At pH 5.5, this fungus hydrolyzed p-nitrophenylphosphate (p-NPP) to p-nitrophenol (p-NP) at a rate of 12.78 +/- 0.53 nmol p-NP per h per mg hyphal dry weight. The values of Vmax and apparent Km for p-NPP hydrolyses were measured as 17.89 +/- 0.92 nmol p-NP per h per mg hyphal dry weight and 1.57 +/- 0.26 mmol/l, respectively. This activity was inhibited at increased pH, a finding compatible with an acid phosphatase. The enzymatic activity was strongly inhibited by classical inhibitors of acid phosphatases such as sodium orthovanadate (Ki = 4.23 micromol/l), sodium molybdate (Ki = 7.53 micromol/l) and sodium fluoride (Ki = 126.78 micromol/l) in a dose-dependent manner. Levamizole (1 mmol/l) and sodium tartrate (10 mmol/l), had no effect on the enzyme activity. Cytochemical localization of the acid phosphatase showed electrondense cerium phosphate deposits on the cell wall, as visualized by transmission electron microscopy. Phosphatase activity in F. pedrosoi seems to be associated with parasitism, as sclerotic cells, which are the fungal forms mainly detected in chromoblastomycosis lesions, showed much higher activities than conidia and mycelia did. A strain of F. pedrosoi recently isolated from a human case of chromoblastomycosis also showed increased enzyme activity, suggesting that the expression of surface phosphatases may be stimulated by interaction with the host.
Collapse
Affiliation(s)
- L F Kneipp
- Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | | | | | | | | |
Collapse
|
52
|
Berón W, Alvarez-Dominguez C, Mayorga L, Stahl PD. Membrane trafficking along the phagocytic pathway. Trends Cell Biol 2004; 5:100-4. [PMID: 14732163 DOI: 10.1016/s0962-8924(00)88958-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phagosome maturation involves extensive remodelling of the phagosomal membrane as a result of intracellular transport events. Newly formed phagosomes exchange membrane-associated and soluble proteins with early endosomes by fusion. Budding of vesicles from the phagosome and fusion with Golgi-derived vesicles may also contribute to the remodelling of the phagosomal compartment. As a consequence of changes in membrane composition, phagosomes acquire the ability to fuse with late endocytic compartments. In vitro reconstitution and other studies suggest that the trafficking events underlying phagosome maturation require several GTP-binding proteins, including Rab5 and Galphas', NSF-SNAP-SNARE complexes and coatomers.
Collapse
Affiliation(s)
- W Berón
- Dept of Cell Biology and Physiology, Washington University Medical School, St Louis, MO 63110, USA
| | | | | | | |
Collapse
|
53
|
Marcilla A, Rubia JEDL, Espert A, Carpena I, Esteban JG, Toledo R. Specific tyrosine phosphorylation in response to bile in Fasciola hepatica and Echinostoma friedi. Exp Parasitol 2004; 106:56-8. [PMID: 15013790 DOI: 10.1016/j.exppara.2004.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2003] [Revised: 01/20/2004] [Accepted: 01/23/2004] [Indexed: 11/17/2022]
Abstract
Protein tyrosine phosphorylation (PY) is a well-known signalling mechanism which is also involved in host-parasite interactions. Despite its transcendence, PY has been poorly studied in parasitic helminths. The aim of this study is to examine the effect of bile salts on the PY pattern in parasitic trematodes. Two distinct adult models were analysed: Echinostoma friedi, of intestinal habitat, and Fasciola hepatica, naturally inhabitant of host biliary channels. Our results show that bile salts induce specific and distinct protein PY in both trematode species, indicating that this signalling process seems to be also involved in host-trematode relationships.
Collapse
Affiliation(s)
- Antonio Marcilla
- Departamento de Parasitología y Biología Celular, Facultad de Farmacia, Universidad de Valencia, Av. Vicent Andrés Estellés s/n, 46100 Burjassot, Valencia, Spain.
| | | | | | | | | | | |
Collapse
|
54
|
Khullar M, Singh RD, Smriti M, Ganguly NK. Anaerobiosis-induced virulence of Salmonella enterica subsp. enterica serovar Typhimurium: role of phospholipase Cgamma signalling cascade. J Med Microbiol 2003; 52:741-745. [PMID: 12909648 DOI: 10.1099/jmm.0.05186-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) can initiate entry into non-phagocytic epithelial cells by triggering certain signal transduction pathways, thereby allowing the pathogen to invade and establish a niche within host cells. Anaerobiosis has been shown to be an important inducer of the invasion process of S. Typhimurium. However, the effect of anaerobiosis on modulation of cell signalling cascades by S. Typhimurium is not known. In the present study, the phospholipase Cgamma signalling cascade was investigated in mice enterocytes, following interaction with S. Typhimurium grown under aerobic and anaerobic growth conditions. Significant increases in enterocyte intracellular calcium and inositol 1,4,5-triphosphate levels were observed on interaction with S. Typhimurium grown anaerobically compared with S. Typhimurium grown aerobically. An increased membrane/cytosolic ratio of protein kinase C was also seen with anaerobic S. Typhimurium in enterocytes compared with aerobic S. Typhimurium. These data suggest that anaerobically grown organisms are more efficient in initiating cell-signalling events than are aerobically grown bacteria. These enhanced cell signals may contribute to the increased virulence of S. Typhimurium grown anaerobically.
Collapse
Affiliation(s)
- Madhu Khullar
- Departments of Experimental Medicine and Biotechnology1 and Medical Microbiology2, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Raman Deep Singh
- Departments of Experimental Medicine and Biotechnology1 and Medical Microbiology2, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Manu Smriti
- Departments of Experimental Medicine and Biotechnology1 and Medical Microbiology2, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Nirmal Kumar Ganguly
- Departments of Experimental Medicine and Biotechnology1 and Medical Microbiology2, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| |
Collapse
|
55
|
Fowler T, Johansson S, Wary KK, Höök M. Src kinase has a central role in in vitro cellular internalization of Staphylococcus aureus. Cell Microbiol 2003; 5:417-26. [PMID: 12780779 DOI: 10.1046/j.1462-5822.2003.00290.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Traditionally recognized as an extracellular pathogen, the Gram-positive bacterium Staphylococcus aureus can also be internalized by a variety of cell types in vitro. Internalization is known to involve binding of the host extracellular protein fibronectin to the bacterium, recognition of the fibronectin-coated bacterium by the fibronectin-binding integrin alpha5beta1 on the host cell surface, and integrin-mediated internalization. Here we examine elements of mammalian cell signalling pathways involved in S. aureus internalization. The mouse fibroblast cell line GD25, in which the gene encoding the beta1 integrin subunit is inactivated, has been complemented with a beta1 integrin cDNA encoding a tyrosine (Y) to phenylalanine (F) mutation in each of the two beta1 integrin intracellular NPXY motifs. This cell line, GD25beta1 A Y783/795F, is defective in migration on fibronectin coated surfaces and intracellular signalling activities involving the tyrosine kinase Src. GD25beta1 A Y783/795F cells have a decreased ability to internalize S. aureus compared to GD25beta1 A cells expressing wild-type beta1 integrins. Furthermore, using mouse embryo fibroblasts in which different members of the Src family kinases are genetically inactivated, we demonstrate that optimal internalization is dependent on expression of Src kinase. Interferon, which has been implicated in repression of the effects of the viral homologue of Src inhibits internalization of S. aureus indicating that internalization may be blocked by inhibitors of Src kinase function. We then demonstrate that Src family kinase specific inhibitors effectively block S. aureus internalization into HeLa cells leading to the conclusion that a function unique to Src is required for optimal internalization of S. aureus in vitro.
Collapse
Affiliation(s)
- Trent Fowler
- Department of Biochemistry and Biophysics, Institute of Biosciences and Technology, Texas A and M University System Health Science Center, Houston, TX, USA
| | | | | | | |
Collapse
|
56
|
Galdiero M, D'Isanto M, Vitiello M, Finamore E, Peluso L, Galdiero M. Monocytic activation of protein tyrosine kinase, protein kinase A and protein kinase C induced by porins isolated from Salmonella enterica serovar Typhimurium. J Infect 2003; 46:111-9. [PMID: 12634073 DOI: 10.1053/jinf.2002.1068] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVES In the present study a monocytic cell line, U937, was used to investigate the possible involvement of protein tyrosine kinases (NT-PTKs), protein kinase A (PKA) and protein kinase C (PKC) in cell signaling pathways following Salmonella enterica serovar Typhimurium porin stimulation. METHODS Different concentrations of porins and lipopolysaccharide (LPS) were analysed to evaluate changes in PTK activity by a non radioactive tyrosine kinase assay and in PKA and PKC phosphorylation by Western blotting analysis. The inhibitors of PTK, PKA and PKC activation used, were: 3,4-dihydroxybenzylidene-malononitrile (tyrphostin 23), inhibitor of epidermal growth factor (EGF) receptor tyrosine kinase activity; dihychloride (H-89), a selective inhibitor of PKA which is useful to discriminate between the effects of PKC and PKA; diacylglycerol kinase inhibitor II (R59949), which is useful for elucidating roles of PKC; calphostin C, a specific inhibitor of PKC. RESULTS Porins of the outer membrane of the ST were isolated to be used as a stimulus in the performed experiments. Following porin treatment, a dose-dependent increase in PTK, PKA and PKC activation was observed. U937 monocytes pretreated with inhibitors induced an evident decrease in PTK activity and PKA and PKC phosphorylation pattern in porin stimulated monocytes. CONCLUSIONS Our data support the important role played by NT-PTK, PKA and PKC in transducing the activating signal in macrophages stimulated with porins through the activation of the mitogen-activated protein kinase (MAPK) pathway that participate in the regulation of gene expression.
Collapse
Affiliation(s)
- M Galdiero
- Dipartimento di Medicina, Sperimentale, Sezione di Microbiologia e Microbiologia Clinica, facoltà di Medicina e Chiruga, Seconda Università degli Studi di Napoli, Italy.
| | | | | | | | | | | |
Collapse
|
57
|
Naranatt PP, Akula SM, Zien CA, Krishnan HH, Chandran B. Kaposi's sarcoma-associated herpesvirus induces the phosphatidylinositol 3-kinase-PKC-zeta-MEK-ERK signaling pathway in target cells early during infection: implications for infectivity. J Virol 2003; 77:1524-39. [PMID: 12502866 PMCID: PMC140802 DOI: 10.1128/jvi.77.2.1524-1539.2003] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human herpesvirus 8 (HHV-8) is implicated in the pathogenesis of Kaposi's sarcoma. HHV-8 envelope glycoprotein B (gB) possesses the RGD motif known to interact with integrin molecules, and HHV-8 infectivity was inhibited by RGD peptides, by antibodies against alpha3 and beta1 integrins, and by soluble alpha3beta1 integrin (S. M. Akula, N. P. Pramod, F.-Z. Wang, and B. Chandran, Cell 108:407-419, 2002). Anti-gB antibodies immunoprecipitated the virus alpha3 and beta1 complexes, and virus-binding studies suggest a role for alpha3beta1 in HHV-8 entry. HHV-8 infection induced the integrin-mediated activation of focal adhesion kinase (FAK), implicating a role for integrin and the associated signaling pathways in HHV-8 entry into the target cells. Immediately after infection, target cells exhibited morphological changes and cytoskeletal rearrangements, suggesting the induction of signal pathways. As early as 5 min postinfection, HHV-8 activated the MEK-ERK1/2 pathway. The focal adhesion components phosphatidylinositol 3-kinase (PI 3-kinase) and protein kinase C-zeta (PKC-zeta) were recruited as upstream mediators of the HHV-8-induced ERK pathway. Anti-HHV-8 gB-neutralizing antibodies and soluble alpha3beta1 integrin inhibited the virus-induced signaling pathways. Early kinetics of the cellular signaling pathway and its activation by UV-inactivated HHV-8 suggest a role for virus binding and/or entry but not viral gene expression in this induction. Studies with human alpha3 integrin-transfected Chinese hamster ovary cells and FAK-negative mouse DU3 cells suggest that the alpha3beta1 integrin and FAK play roles in the HHV-8 mediated signal induction. Inhibitors specific for PI 3-kinase, PKC-zeta, MEK, and ERK significantly reduced the virus infectivity without affecting virus binding to the target cells. Examination of viral DNA entry suggests a role for PI 3-kinase in HHV-8 entry into the target cells and a role for PKC-zeta, MEK, and ERK at a post-viral entry stage of infection. These findings implicate a critical role for integrin-associated mitogenic signaling in HHV-8's infection of target cells and suggest that, by orchestrating the signal cascade, HHV-8 may create an appropriate intracellular environment to facilitate the infection.
Collapse
Affiliation(s)
- Pramod P Naranatt
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City 66160, USA
| | | | | | | | | |
Collapse
|
58
|
Kerro Dego O, van Dijk JE, Nederbragt H. Factors involved in the early pathogenesis of bovine Staphylococcus aureus mastitis with emphasis on bacterial adhesion and invasion. A review. Vet Q 2002; 24:181-98. [PMID: 12540135 DOI: 10.1080/01652176.2002.9695135] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
Abstract
Staphylococcus aureus is the most important and prevalent contagious mammary pathogen; it causes clinical and subclinical intramammary infection with serious economic loss and herd management problems in dairy cows. In vitro studies have shown that Staphylococcus aureus adheres to mammary epithelial cells and extracellular matrix components and invades into mammary epithelial as well as other mammary cells. Staphylococcus aureus strains from intramammary infection produce several cell surface-associated and extracellular secretory products. The exact pathogenic roles of most of the products and their effects on adhesion and invasion are not well evaluated. It is also known that mammary epithelial cell-associated molecules and extracellular matrix components interact with S. aureus during the pathogenesis of mastitis, but their roles on adhesion and invasion have not been characterized. The adhesion of S. aureus to epithelial cells may involve non-specific physicochemical interactions and/or specific interactions between bacterial cell-associated ligands and host cell surface receptors. In vitro adhesion depends on the S. aureus strain, the growth phase of the bacteria, the growth medium and the origin of the epithelial cells. Adhesion is hypothesized to be a prerequisite and crucial early step for mammary gland infection. Staphylococcus aureus invades mammary epithelial cells. It also invades other cells such as endothelial cells and fibroblasts. Bacteria are found enclosed in membrane bound vacuoles in the cytoplasm of mammary epithelial cells. Recent observations indicate that S. aureus escapes from the phagosome into the cytoplasm and induces apoptosis. The invasion into mammary epithelial cells may occur through an endocytic process that requires involvement of elements of the cytoskeleton or by direct binding of bacteria to epithelial cells through a process mediated by specific receptors that needs de novo protein synthesis by both cells. Thus, the recurrent subclinical infection may result from this intracellular existence of bacteria that are protected from host defenses and effects of antibiotics. This review emphasizes on recent findings on S. aureus adhesion to mammary epithelial cells and extracellular matrix components and invasion into mammary epithelial cells.
Collapse
Affiliation(s)
- O Kerro Dego
- Department of Pathology, Faculty of Veterinary Medicine, Utrecht University, P.O. Box: 80158 3508 TD, Utrecht, The Netherlands.
| | | | | |
Collapse
|
59
|
Lawton DG, Longstaff C, Wallace BA, Hill J, Leary SEC, Titball RW, Brown KA. Interactions of the type III secretion pathway proteins LcrV and LcrG from Yersinia pestis are mediated by coiled-coil domains. J Biol Chem 2002; 277:38714-22. [PMID: 12107165 DOI: 10.1074/jbc.m203632200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The type III secretion system is used by pathogenic Yersinia to translocate virulence factors into the host cell. A key component is the multifunctional LcrV protein, which is present on the bacterial surface prior to host cell contact and up-regulates translocation by blocking the repressive action of the LcrG protein on the cytosolic side of the secretion apparatus. The functions of LcrV are proposed to involve self-interactions (multimerization) and interactions with other proteins including LcrG. Coiled-coil motifs predicted to be present are thought to play a role in mediating these protein-protein interactions. We have purified recombinant LcrV, LcrG, and site-directed mutants of LcrV and demonstrated the structural integrity of these proteins using circular dichroism spectroscopy. We show that LcrV interacts both with itself and with LcrG and have obtained micromolar and nanomolar affinities for these interactions, respectively. The effects of LcrV mutations upon LcrG binding suggest that coiled-coil interactions indeed play a significant role in complex formation. In addition, comparisons of secretion patterns of effector proteins in Yersinia, arising from wild type and mutants of LcrV, support the proposed role of LcrG in titration of LcrV in vivo but also suggest that other factors may be involved.
Collapse
Affiliation(s)
- Daniel G Lawton
- Department of Biological Sciences, Centre for Molecular Microbiology and Infection, Flowers Building, Imperial College of Science, Technology and Medicine, London SW7 2AY, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
60
|
Abstract
The protozoan parasite Trypanosoma cruzi is responsible for Chagas disease, a serious debilitating disease that affects millions of people in Latin America. Trypomastigotes, the infective forms, are capable of invading and replicating in different cell types. The invasion process involves a gradual recruitment and fusion of host cell lysosomes at the parasite entry site, and is regulated by intracellular free Ca2+ transients triggered by trypomastigotes in host cells. This unusual, Ca2+-dependent lysosome exocytosis pathway was recently shown to be involved in the mechanism by which mammalian cells repair lesions on their plasma membrane.
Collapse
Affiliation(s)
- Henry Tan
- Section of Microbial Pathogenesis and Dept of Cell Biology, Boyer Center for Molecular Medicine, Yale University School of Medicine, 295 Congress Avenue, New Haven, CT 06536, USA
| | | |
Collapse
|
61
|
Eitel J, Dersch P. The YadA protein of Yersinia pseudotuberculosis mediates high-efficiency uptake into human cells under environmental conditions in which invasin is repressed. Infect Immun 2002; 70:4880-91. [PMID: 12183532 PMCID: PMC128239 DOI: 10.1128/iai.70.9.4880-4891.2002] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The YadA protein is a major adhesin of Yersinia pseudotuberculosis that promotes tight adhesion to mammalian cells by binding to extracellular matrix proteins. In this study, we first addressed the possibility of competitive interference of YadA and the major invasive factor invasin and found that expression of YadA in the presence of invasin affected neither the export nor the function of invasin in the outer membrane. Furthermore, expression of YadA promoted both bacterial adhesion and high-efficiency invasion entirely independently of invasin. Antibodies against fibronectin and beta(1) integrins blocked invasion, indicating that invasion occurs via extracellular-matrix-dependent bridging between YadA and the host cell beta(1) integrin receptors. Inhibitor studies also demonstrated that tyrosine and Ser/Thr kinases, as well as phosphatidylinositol 3-kinase, are involved in the uptake process. Further expression studies revealed that yadA is regulated in response to several environmental parameters, including temperature, ion and nutrient concentrations, and the bacterial growth phase. In complex medium, YadA production was generally repressed but could be induced by addition of Mg(2+). Maximal expression of yadA was obtained in exponential-phase cells grown in minimal medium at 37 degrees C, conditions under which the invasin gene is repressed. These results suggest that YadA of Y. pseudotuberculosis constitutes another independent high-level uptake pathway that might complement other cell entry mechanisms (e.g., invasin) at certain sites or stages during the infection process.
Collapse
Affiliation(s)
- Julia Eitel
- Department of Microbiology, Institute of Microbiology and Plant Physiology, Freie Universität Berlin, 14195 Berlin, Germany
| | | |
Collapse
|
62
|
Vieira LL, Sacerdoti-Sierra N, Jaffe CL. Effect of pH and temperature on protein kinase release by Leishmania donovani. Int J Parasitol 2002; 32:1085-93. [PMID: 12117491 DOI: 10.1016/s0020-7519(02)00067-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
During their life cycle Leishmania are exposed to environments that differ markedly in pH and temperature. The effect of these factors on protein kinase release into the surrounding environment by Leishmania donovani promastigotes was examined. Promastigotes release protein kinase activity both constitutively and following induction by incubation with an exogenous substrate, phosvitin. The substrate specificity of the constitutive and induced activities was similar, unlike that previously described for Leishmania major promastigotes. The Leishmania donovani enzymes phosphorylate phosvitin, but not casein, mixed histones or protamine sulphate, and both activities are shed over a wide pH range from 6 to 9. Transfer of promastigotes from pH 7.4/30 degrees C to pH 5.0-5.5/37 degrees C, conditions that mimic those encountered by parasites following transmission from sandflies to a mammalian host and uptake by macrophages, inhibited release of the constitutive activity. Identical conditions had only a minor effect on induced protein kinase release. Both types of protein kinase activities released at pH 7.4 were still active when assayed at pH 5.0. Characterisation of the constitutive and induced promastigote protein kinases showed that casein kinase 1- and casein kinase 2-like activities are released by Leishmania donovani. Constitutive enzyme release decreased over time, however, the addition of phosvitin to these "casein kinase-depleted" promastigotes induced elevated casein kinase 1 and casein kinase 2 shedding. These results suggest that shed protein kinase might play a role in parasite survival and adaptation to host environments.
Collapse
Affiliation(s)
- Lita L Vieira
- Department of Parasitology, The Kuvin Centre for the Study of Infectious and Tropical Diseases, Hebrew University-Hadassah Medical School, P.O. Box 12272, 91120 Jerusalem, Israel
| | | | | |
Collapse
|
63
|
Evans DJ, Maltseva IA, Wu J, Fleiszig SMJ. Pseudomonas aeruginosa internalization by corneal epithelial cells involves MEK and ERK signal transduction proteins. FEMS Microbiol Lett 2002; 213:73-9. [PMID: 12127491 DOI: 10.1111/j.1574-6968.2002.tb11288.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Invasion of epithelial cells represents a potential pathogenic mechanism for Pseudomonas aeruginosa. We explored the role of mitogen-activated protein kinase kinases (MEK 1/2) and the extracellular signal-regulated kinases (ERK 1/2) in P. aeruginosa invasion. Treatment of corneal epithelial cells with MEK inhibitors, PD98059 (20 microM) or UO126 (100 microM), reduced P. aeruginosa invasion by approximately 60% without affecting bacterial association with the cells (P=0.0001). UO124, a negative control for UO126, had no effect on bacterial internalization. Infection of cells with an internalization-defective flhA mutant of P. aeruginosa was associated with less ERK 1/2 tyrosine phosphorylation than infection with wild-type invasive P. aeruginosa. An ERK-2 inhibitor, 5-iodotubercidin (20 microM), reduced P. aeruginosa invasion by approximately 40% (P=0.035). Together, these data suggest that P. aeruginosa internalization by epithelial cells involves a pathway(s) that includes MEK and ERK signaling proteins.
Collapse
Affiliation(s)
- David J Evans
- Morton D. Sarver Laboratory for Cornea and Contact Lens Research, School of Optometry, University of California, Berkeley, CA 94720, USA
| | | | | | | |
Collapse
|
64
|
Lee SW, Bonnah RA, Higashi DL, Atkinson JP, Milgram SL, So M. CD46 is phosphorylated at tyrosine 354 upon infection of epithelial cells by Neisseria gonorrhoeae. J Cell Biol 2002; 156:951-7. [PMID: 11901164 PMCID: PMC2173477 DOI: 10.1083/jcb.200109005] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Neisseria type IV pilus promotes bacterial adhesion to host cells. The pilus binds CD46, a complement-regulatory glycoprotein present on nucleated human cells (Källström et al., 1997). CD46 mutants with truncated cytoplasmic tails fail to support bacterial adhesion (Källström et al., 2001), suggesting that this region of the molecule also plays an important role in infection. Here, we report that infection of human epithelial cells by piliated Neisseria gonorrhoeae (GC) leads to rapid tyrosine phosphorylation of CD46. Studies with wild-type and mutant tail fusion constructs demonstrate that Src kinase phosphorylates tyrosine 354 in the Cyt2 isoform of the CD46 cytoplasmic tail. Consistent with these findings, infection studies show that PP2, a specific Src family kinase inhibitor, but not PP3, an inactive variant of this drug, reduces the ability of epithelial cells to support bacterial adhesion. Several lines of evidence point to the role of c-Yes, a member of the Src family of nonreceptor tyrosine kinases, in CD46 phosphorylation. GC infection causes c-Yes to aggregate in the host cell cortex beneath adherent bacteria, increases binding of c-Yes to CD46, and stimulates c-Yes kinase activity. Finally, c-Yes immunoprecipitated from epithelial cells is able to phosphorylate the wild-type Cyt2 tail but not the mutant derivative in which tyrosine 354 has been substituted with alanine. We conclude that GC infection leads to rapid tyrosine phosphorylation of the CD46 Cyt2 tail and that the Src kinase c-Yes is involved in this reaction. Together, the findings reported here and elsewhere strongly suggest that pilus binding to CD46 is not a simple static process. Rather, they support a model in which pilus interaction with CD46 promotes signaling cascades important for Neisseria infectivity.
Collapse
Affiliation(s)
- Shaun W Lee
- Department of Molecular Microbiology and Immunology, L220, Oregon Health and Science University, Portland, OR 97201
| | | | | | | | | | | |
Collapse
|
65
|
Tucker SC, Casadevall A. Replication of Cryptococcus neoformans in macrophages is accompanied by phagosomal permeabilization and accumulation of vesicles containing polysaccharide in the cytoplasm. Proc Natl Acad Sci U S A 2002; 99:3165-70. [PMID: 11880650 PMCID: PMC122490 DOI: 10.1073/pnas.052702799] [Citation(s) in RCA: 226] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cryptococcus neoformans (CN), an encapsulated, ubiquitous environmental yeast, is pathogenic for humans, primarily those with compromised immune function. CN is believed to be a facultative intracellular pathogen. Time-lapsed video microscopy revealed that yeast began to replicate and divide 2 hours after ingestion by J774.16 macrophage cells, with the average cell hosting 10-40 organisms of varying morphologies before ultimately lysing and releasing organisms, either singly or in clumps. Intracellular growth was accompanied by the accumulation of polysaccharide-filled vesicles in the macrophage. Studies with fluorescently labeled dextran revealed that the phagolysosomal compartment became leaky during the course of intracellular infection. Consistent with this observation, phagosomes containing CN had an increased pH relative to similar phagosomes containing inert magnetic beads, as indicated by a colorimetric change in the pH-sensitive Lysosensor dye. Immunocytochemistry revealed differences in the reactivity of polysaccharide elaborated by CN inside macrophages relative to that expressed in vitro. Taken together these results are suggestive of a novel mechanism of intracellular survival by an encapsulated organism, whereby ingestion is followed by damage to the phagosomal membrane resulting in continuity with the cytoplasm, accumulation of polysaccharide-containing vesicles, and possibly, production of a structurally different polysaccharide.
Collapse
Affiliation(s)
- Stephanie C Tucker
- Department of Medicine, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA
| | | |
Collapse
|
66
|
Martinez JJ, Hultgren SJ. Requirement of Rho-family GTPases in the invasion of Type 1-piliated uropathogenic Escherichia coli. Cell Microbiol 2002; 4:19-28. [PMID: 11856170 DOI: 10.1046/j.1462-5822.2002.00166.x] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Bladder infections caused by uropathogenic Escherichia coli (UPEC) depends on the ability of E. coli to express type 1 pili. The adhesive component of the pilus, FimH, mediates the invasion of E. coli into the bladder epithelium, a mechanism that facilitates the survival and persistence of E. coli in the bladder. The invasion mechanism requires actin polymerization, focal adhesion kinase phosphorylation and PI 3-kinase activation as well as the formation of FAK/PI 3-kinase and downstream vinculin/alpha-actinin complexes. In this study, we report a role for Rho-GTPase family members, namely RhoA, Cdc42 and Rac1, in the invasion process. Internalization of type 1-piliated E. coli (fimH+) and FimH-coated micro-spheres was inhibited by compactin, a pan-Rho-GTPase inhibitor and dominant negative isoforms of Rac1 and Cdc42. Expression of active Rac1 induced an internalization of E. coli that was insensitive to wortmannin and genistein. Expression of constitutively active Cdc42 induced the formation of FAK/PI 3-kinase and vinculin/alpha-actinin complexes whereas active Rac1 induced only a vinculin/alpha-actinin complex. Taken together, these data suggest that FimH-mediated invasion is dependent on GTP-binding protein activity that involves Cdc42 and PI 3-kinase activation probably upstream of Rac1.
Collapse
Affiliation(s)
- Juan J Martinez
- Department of Molecular Microbiology and Microbial Pathogenesis, Washington University School of Medicine, St. Louis, MO 63110, USA
| | | |
Collapse
|
67
|
Chitale S, Ehrt S, Kawamura I, Fujimura T, Shimono N, Anand N, Lu S, Cohen-Gould L, Riley LW. Recombinant Mycobacterium tuberculosis protein associated with mammalian cell entry. Cell Microbiol 2001; 3:247-54. [PMID: 11298648 DOI: 10.1046/j.1462-5822.2001.00110.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ability to gain entry and resist the antimicrobial intracellular environment of mammalian cells is an essential virulence property of Mycobacterium tuberculosis. A purified recombinant protein expressed by a 1362 bp locus (mce1) in the M. tuberculosis genome promoted uptake into HeLa cells of polystyrene latex microspheres coated with the protein. N-terminus deletion constructs of Mce1 identified a domain located between amino acid positions 106 and 163 that was needed for this cell uptake activity. Mce1 contained hydrophobic stretches at the N-terminus predictive of a signal sequence, and colloidal gold immunoelectron microscopy indicated that the corresponding native protein is expressed on the surface of the M. tuberculosis organism. The complete M. tuberculosis genome sequence revealed that it contained four homologues of mce (mce1, mce2, mce3, mce4) and that they were all located within operons composed of genes arranged similarly at different locations in the chromosome. Recombinant Mce2, which had the highest level of identity (67%) to Mce1, was unable to promote the association of microspheres with HeLa cells. Although the exact function of Mce1 is still unknown, it appears to serve as an effector molecule expressed on the surface of M. tuberculosis that is capable of eliciting plasma membrane perturbations in non-phagocytic mammalian cells.
Collapse
Affiliation(s)
- S Chitale
- Department of Medicine, Weill Medical College of Cornell University New York, NY, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
68
|
Abstract
Immune panels of many autism-spectrum children reveal signs of atypical infections and shifted cell counts. In conjunction with trait-related cerebral hypometabolism and hypoperfusion, these findings suggest a hypothesis: Several autism-spectrum subgroups derive from intra-monocyte pathogens such as measles virus, cytomegalovirus, human herpesvirus 6, and Yersinia enterocolitica. Furthermore, with much inter-child variation, their effects manifest as diminished hematopoiesis, impaired peripheral immunity, and altered blood-brain barrier function often accompanied by demyelination. In some such children, one or more of these pathogens persists as a chronic-active, seemingly subclinical infection etiologically significant to the child's autistic traits. Within these subgroups, immune impairments and atypical infections may be treatable.
Collapse
Affiliation(s)
- T Binstock
- Institute for Molecular Introspections, Estes Park, Colorado, USA.
| |
Collapse
|
69
|
Affiliation(s)
- J Pieters
- Basel Institute for Immunology, Switzerland
| |
Collapse
|
70
|
Islam D, Bandholtz L, Nilsson J, Wigzell H, Christensson B, Agerberth B, Gudmundsson G. Downregulation of bactericidal peptides in enteric infections: a novel immune escape mechanism with bacterial DNA as a potential regulator. Nat Med 2001; 7:180-5. [PMID: 11175848 DOI: 10.1038/84627] [Citation(s) in RCA: 295] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Antibacterial peptides are active defense components of innate immunity. Several studies confirm their importance at epithelial surfaces as immediate barrier effectors in preventing infection. Here we report that early in Shigella spp. infections, expression of the antibacterial peptides LL-37 and human beta-defensin-1 is reduced or turned off. The downregulation is detected in biopsies from patients with bacillary dysenteries and in Shigella- infected cell cultures of epithelial and monocyte origin. This downregulation of immediate defense effectors might promote bacterial adherence and invasion into host epithelium and could be an important virulence parameter. Analyses of bacterial molecules causing the downregulation indicate Shigella plasmid DNA as one mediator.
Collapse
Affiliation(s)
- D Islam
- Laboratory Sciences Division, International Center for Diarrhoeal Disease Research, 1000 Dhaka, Bangladesh
| | | | | | | | | | | | | |
Collapse
|
71
|
Esen M, Grassmé H, Riethmüller J, Riehle A, Fassbender K, Gulbins E. Invasion of human epithelial cells by Pseudomonas aeruginosa involves src-like tyrosine kinases p60Src and p59Fyn. Infect Immun 2001; 69:281-7. [PMID: 11119516 PMCID: PMC97882 DOI: 10.1128/iai.69.1.281-287.2001] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa plays a major role in respiratory tract infections or sepsis in patients with cystic fibrosis or upon suppression of the immune system. Several P. aeruginosa strains have been shown to be internalized by human epithelial cells; however, the molecular mechanisms of the invasion process are poorly characterized. Here, we show that the internalization of P. aeruginosa into human epithelial cells results in and requires activation of the Src-like tyrosine kinases p59Fyn and p60Src and the consequent tyrosine phosphorylation of several eukaryotic proteins. The significance of Src-like tyrosine kinase activation is shown by an almost complete blockade of P. aeruginosa internalization, but not adhesion, upon inhibition of Src-like tyrosine kinases. Likewise, inhibition of P. aeruginosa binding to CFTR, which has been shown to block P. aeruginosa internalization, prevents Src and Fyn activation, supporting a pivotal role of Src-like tyrosine kinases for invasion by P. aeruginosa.
Collapse
Affiliation(s)
- M Esen
- Department of Physiology, University of Tuebingen, 72076 Tuebingen, Germany
| | | | | | | | | | | |
Collapse
|
72
|
Ruhl S, Cisar JO, Sandberg AL. Identification of polymorphonuclear leukocyte and HL-60 cell receptors for adhesins of Streptococcus gordonii and Actinomyces naeslundii. Infect Immun 2000; 68:6346-54. [PMID: 11035744 PMCID: PMC97718 DOI: 10.1128/iai.68.11.6346-6354.2000] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interactions of oral streptococci and actinomyces with polymorphonuclear leukocytes (PMNs), mediated by sialic acid- and Gal/GalNAc-reactive adhesins, respectively, result in activation of the PMNs and thereby may contribute to the initiation of oral inflammation. Sialidase treatment of PMNs or HL-60 cells abolished adhesion of Streptococcus gordonii but was required for adhesion of Actinomyces naeslundii. The same effects of sialidase were noted for adhesion of these bacteria to a major 150-kDa surface glycoprotein of either PMNs or undifferentiated HL-60 cells and to a 130-kDa surface glycoprotein of differentiated HL-60 cells. These glycoproteins were both identified as leukosialin (CD43) by immunoprecipitation with a specific monoclonal antibody (MAb). Adhesion of streptococci and actinomyces to a 200-kDa minor PMN surface glycoprotein was also detected by bacterial overlay of untreated and sialidase-treated nitrocellulose transfers, respectively. This glycoprotein was identified as leukocyte common antigen (CD45) by immunoprecipitation with a specific MAb. CD43 and CD45 both possess extracellular mucinlike domains in addition to intracellular domains that are implicated in signal transduction. Consequently, the interactions of streptococci and actinomyces with the mucinlike domains of these mammalian cell surface glycoproteins result not only in adhesion but, in addition, may represent the initial step in PMN activation by these bacteria.
Collapse
Affiliation(s)
- S Ruhl
- Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | |
Collapse
|
73
|
Smith VP, Selkirk ME, Gounaris K. A reversible protein phosphorylation system is present at the surface of infective larvae of the parasitic nematode Trichinella spiralis. FEBS Lett 2000; 483:104-8. [PMID: 11042262 DOI: 10.1016/s0014-5793(00)02094-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Trichinella spiralis infective larvae have externally oriented enzymes catalysing reversible protein phosphorylation on their surface. Incubation of larvae with exogenous ATP resulted in phosphorylation of surface bound and released proteins. Exposure of the parasites to bile, a treatment which renders them infective for intestinal epithelia, resulted in increased release of protein and an altered profile of phosphorylation. Both serine/threonine and tyrosine phosphorylation and dephosphorylation reactions took place at the parasite surface. Examination of the structural characteristics of the larvae following exposure to bile showed that the non-bilayer surface coat was not shed but was structurally reorganised.
Collapse
Affiliation(s)
- V P Smith
- Department of Biochemistry, Imperial College of Science, Technology and Medicine, London SW7 2AY, UK
| | | | | |
Collapse
|
74
|
Nixon CS, Steffen MJ, Ebersole JL. Cytokine responses to treponema pectinovorum and treponema denticola in human gingival fibroblasts. Infect Immun 2000; 68:5284-92. [PMID: 10948156 PMCID: PMC101790 DOI: 10.1128/iai.68.9.5284-5292.2000] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human gingival fibroblasts were challenged with Treponema pectinovorum and Treponema denticola to test three specific hypotheses: (i) these treponemes induce different cytokine profiles from the fibroblasts, (ii) differences in cytokine profiles are observed after challenge with live versus killed treponemes, and (iii) differences in cytokine profiles are noted from different gingival fibroblast cell lines when challenged with these treponemes. Three normal gingival fibroblast cell cultures were challenged with T. pectinovorum and T. denticola strains, and the supernatants were analyzed for cytokine production (i.e., interleukin-1alpha [IL-1alpha], IL-1beta, IL-6, IL-8, IL-10, gamma interferon, macrophage chemotactic protein 1 [MCP-1], platelet-derived growth factor, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor). Unstimulated fibroblast cell lines produced IL-6, IL-8, and MCP-1. T. pectinovorum routinely elicited the greatest production of these cytokines from the fibroblast cell lines, increasing 10- to 50-fold over basal production. While T. denticola also induced IL-6 and IL-8 production, these levels were generally lower than those elicited by challenge with T. pectinovorum. MCP-1 levels were significantly lower after T. denticola challenge, and the kinetics suggested that this microorganism actually inhibited basal production by the fibroblasts. No basal or stimulated production of the other cytokines was observed. Significant differences were noted in the responsiveness of the various cell lines with respect to the two species of treponemes and the individual cytokines produced. Finally, dead T. pectinovorum generally induced a twofold-greater level of IL-6 and IL-8 than the live bacteria. These results supported the idea that different species of oral treponemes can elicit proinflammatory cytokine production by gingival cells and that this stimulation did not require live microorganisms. Importantly, a unique difference was noted in the ability of T. pectinovorum to induce a robust MCP-1 production, while T. denticola appeared to inhibit this activity of the fibroblasts. While the general cytokine profiles of the fibroblast cell cultures were similar, significant differences were noted in the quantity of individual cytokines produced, which could relate to individual patient variation in local inflammatory responses in the periodontium.
Collapse
Affiliation(s)
- C S Nixon
- Departments of Microbiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78284, USA
| | | | | |
Collapse
|
75
|
Teoh DA, Kamieniecki D, Pang G, Buret AG. Giardia lamblia rearranges F-actin and alpha-actinin in human colonic and duodenal monolayers and reduces transepithelial electrical resistance. J Parasitol 2000; 86:800-6. [PMID: 10958459 DOI: 10.1645/0022-3395(2000)086[0800:glrfaa]2.0.co;2] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The mechanisms of epithelial injury in giardiasis remain unknown. The effects of live Giardia lamblia on cellular G-actin, F-actin, alpha-actinin, and electrical resistance of human intestinal epithelial monolayers were investigated using SCBN and Caco2 cell lines grown on chamber slides or Transwell filter membranes. In separate experiments, some monolayers were also exposed to sonicated trophozoites, some to supernatant from live G. lamblia cultures, and some with or without the Ca2+ channel blocker verapamil. After 2, 24, or 48 hr of coincubation with G. lamblia, monolayers were assessed for cytoskeletal arrangement under fluorescence and confocal laser microscopy, and transepithelial electrical resistance was measured. Exposure to live G. lamblia trophozoites induced localized condensation of F-actin and loss of perijunctional alpha-actinin while G-actin remained unchanged. Confocal laser microscopy indicated that F-actin rearrangement was not affected by verapamil and was localized within the terminal web area. Coincubation of monolayers with G. lamblia lysates or with spent medium alone similarly rearranged F-actin. Verapamil alone did not alter F-actin. Electrical resistance of SCBN and Caco2 monolayers exposed to G. lamblia was significantly decreased versus controls regardless of whether live or lysed trophozoite samples were used. The results indicate that G. lamblia-induced epithelial injury is associated with F-actin and alpha-actinin rearrangements in the terminal web area via mechanisms independent of extracellular Ca2+. These alterations are associated with reduced transepithelial electrical resistance and are due at least in part to trophozoite products.
Collapse
Affiliation(s)
- D A Teoh
- Department of Biological Sciences, University of Calgary, Alberta, Canada
| | | | | | | |
Collapse
|
76
|
Källström H, Hansson-Palo P, Jonsson AB. Cholera toxin and extracellular Ca2+ induce adherence of non-piliated Neisseria: evidence for an important role of G-proteins and Rho in the bacteria-cell interaction. Cell Microbiol 2000; 2:341-51. [PMID: 11207590 DOI: 10.1046/j.1462-5822.2000.00063.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this study, we characterize the interaction between non-piliated (P-) Neisseria gonorrhoeae and human epithelial cells. P- mutants lacking the pilus subunit protein PilE attach at low levels to cells. Although the binding may not lead to heavy inflammatory responses, the interaction between P- Neisseria and host cells most probably play a role in colonization and asymptomatic carriage of the pathogen. Here we show that the adherence of P N. gonorrhoeae is blocked by GDP-beta-S [guanosine 5'-O(thio)diphosphate], a non-hydrolyzable GTP analogue, and by C3 exotoxin, an inhibitor of the small G-protein Rho. G-protein activators such as cholera toxin, that activates Gs, and fluoroaluminate, a general G-protein activator, induced bacterial adherence. Furthermore, increase of the extracellular free [Ca2+] dramatically enhanced adherence of non-piliated Neisseria. The pharynx and the urogenital tract are natural entry sites of the pathogenic Neisseria species, and at both sites the epithelial cells can be exposed to wide variations in Ca2+ concentration. Taken together, these data show the importance of extracellular Ca2+ in the pathogenic Neisseria-host interaction, and reveal a novel function of cholera toxin, namely induction of bacterial adherence.
Collapse
Affiliation(s)
- H Källström
- Microbiology and Tumorbiology Center, Karolinska Institutet, Stockholm, Sweden
| | | | | |
Collapse
|
77
|
Laughlin RS, Musch MW, Hollbrook CJ, Rocha FM, Chang EB, Alverdy JC. The key role of Pseudomonas aeruginosa PA-I lectin on experimental gut-derived sepsis. Ann Surg 2000; 232:133-42. [PMID: 10862206 PMCID: PMC1421122 DOI: 10.1097/00000658-200007000-00019] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVE To examine the effect of Pseudomonas aeruginosa on intestinal barrier function and its lethal potential when introduced into the intestinal tract of mice. SUMMARY BACKGROUND DATA The mere presence of P. aeruginosa in the intestinal tract of critically ill patients is associated with a threefold increase in death compared with matched cohorts without this pathogen. Whether this effect is a cause or a consequence of the critically ill state has not been previously addressed. METHODS Transepithelial electrical resistance, a measure of tight junction permeability, was evaluated in Caco-2 intestinal epithelial cells cells apically inoculated with live P. aeruginosa, exotoxin A, or purified PA-I lectin, an adhesin of P. aeruginosa. Lethality studies to P. aeruginosa were carried out in mice undergoing 30% surgical hepatectomy by injecting the bacteria or its various components directly into the cecum. RESULTS Only cells exposed to P. aeruginosa or its PA-I lectin developed alterations in barrier function. P. aeruginosa or the combination of PA-I and exotoxin A was lethal to mice when injected into the cecum after partial hepatectomy. Alterations in epithelial barrier function and death in mice were prevented when Pseudomonas was pretreated with N-acetyl D-galactosamine (GalNAc), a binder of PA-I. CONCLUSIONS P. aeruginosa may act as a pathogen in the gastrointestinal tract, resulting in altered epithelial barrier function and death in a susceptible host. The PA-I lectin of P. aeruginosa may play a key role in its pathogenicity to the intestinal epithelium by inducing a permeability defect to its cytotoxic exoproducts such as exotoxin A.
Collapse
Affiliation(s)
- R S Laughlin
- Department of Surgery and Internal Medicine, Section of General Surgery and Gastroenterology, University of Chicago, Chicago, Illinois 60637, USA
| | | | | | | | | | | |
Collapse
|
78
|
Martinez JJ, Mulvey MA, Schilling JD, Pinkner JS, Hultgren SJ. Type 1 pilus-mediated bacterial invasion of bladder epithelial cells. EMBO J 2000; 19:2803-12. [PMID: 10856226 PMCID: PMC203355 DOI: 10.1093/emboj/19.12.2803] [Citation(s) in RCA: 529] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Most strains of uropathogenic Escherichia coli (UPEC) encode filamentous adhesive organelles called type 1 pili. We have determined that the type 1 pilus adhesin, FimH, mediates not only bacterial adherence, but also invasion of human bladder epithelial cells. In contrast, adherence mediated by another pilus adhesin, PapG, did not initiate bacterial internalization. FimH-mediated invasion required localized host actin reorganization, phosphoinositide 3-kinase (PI 3-kinase) activation and host protein tyrosine phosphorylation, but not activation of Src-family tyrosine kinases. Phosphorylation of focal adhesin kinase (FAK) at Tyr397 and the formation of complexes between FAK and PI 3-kinase and between alpha-actinin and vinculin were found to correlate with type 1 pilus-mediated bacterial invasion. Inhibitors that prevented bacterial invasion also blocked the formation of these complexes. Our results demonstrate that UPEC strains are not strictly extracellular pathogens and that the type 1 pilus adhesin FimH can directly trigger host cell signaling cascades that lead to bacterial internalization.
Collapse
Affiliation(s)
- J J Martinez
- Department of Molecular Microbiology and Microbial Pathogenesis, Box 8230, Washington University School of Medicine, 660 S Euclid Avenue St Louis, MO 63110, USA
| | | | | | | | | |
Collapse
|
79
|
Döpfer D, Almeida RA, Lam TJ, Nederbragt H, Oliver SP, Gaastra W. Adhesion and invasion of Escherichia coli from single and recurrent clinical cases of bovine mastitis in vitro. Vet Microbiol 2000; 74:331-43. [PMID: 10831855 DOI: 10.1016/s0378-1135(00)00191-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Seven strains of Escherichia coli, originating from clinical cases of bovine mastitis, and one Salmonella typhimurium control strain were tested for their ability to adhere to, and invade, bovine mammary epithelial cells (MAC-T cells) in vitro. Four of the seven strains were isolated from cows with chronic intramammary infections with recurrent episodes of clinical mastitis and three strains were isolated from single cases of clinical mastitis. Both adhesion and invasion of all strains were dose and time dependent. The four E. coli strains isolated from recurrent cases of clinical mastitis invaded twice as frequently as and three times faster than the strains isolated from single cases of clinical mastitis. By contrast, there was no difference in the amount or speed of adhesion between the two types of strains of E. coli. Adhesion and invasion curves of E. coli resembled a two-step chain reaction, where invasion was the rate-limiting step. Although adhesion and invasion of E. coli has not been demonstrated in vivo yet, the results of the present study may contribute to an understanding of the pathogenesis of chronic intramammary infections caused by E. coli.
Collapse
Affiliation(s)
- D Döpfer
- Department of Bacteriology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3484 CL, Utrecht, The Netherlands.
| | | | | | | | | | | |
Collapse
|
80
|
Herron MJ, Nelson CM, Larson J, Snapp KR, Kansas GS, Goodman JL. Intracellular parasitism by the human granulocytic ehrlichiosis bacterium through the P-selectin ligand, PSGL-1. Science 2000; 288:1653-6. [PMID: 10834846 DOI: 10.1126/science.288.5471.1653] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Human granulocytic ehrlichiosis (HGE) is a febrile tick-borne illness caused by a recently discovered intracellular bacterium remarkable for its tropism for professionally phagocytic neutrophils. Monoclonal antibodies against the P-selectin binding domain of the leukocyte P-selectin glycoprotein ligand, PSGL-1, prevented HGE cell binding and infection, as did enzymatic digestion of PSGL-1. Furthermore, simultaneous neoexpression in nonsusceptible cells of complementary DNAs for both PSGL-1 and its modifying alpha-(1,3) fucosyltransferase, Fuc-TVII, allowed binding and infection by HGE. Thus, the HGE bacterium specifically bound to fucosylated leukocyte PSGL-1. Selectin mimicry is likely central to the organism's unique ability to target and infect neutrophils.
Collapse
Affiliation(s)
- M J Herron
- Division of Infectious Diseases, Department of Medicine, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA
| | | | | | | | | | | |
Collapse
|
81
|
Steffen MJ, Holt SC, Ebersole JL. Porphyromonas gingivalis induction of mediator and cytokine secretion by human gingival fibroblasts. ORAL MICROBIOLOGY AND IMMUNOLOGY 2000; 15:172-80. [PMID: 11154400 DOI: 10.1034/j.1399-302x.2000.150305.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We hypothesized that bacterial viability and strain characteristics of Porphyromonas gingivalis could affect the induction of pro-inflammatory mediator secretion by human gingival fibroblast cultures. Both killed and viable P. gingivalis elicited production of prostaglandin E2, interleukin-1 beta (IL-1 beta), IL-6 and IL-8, although killed P. gingivalis induced generally higher levels, particularly IL-6 and IL-8, compared with the viable bacteria. P. gingivalis strains, which exhibited wild-type levels of trypsin-like protease activity, stimulated human gingival fibroblasts to secrete increased levels of prostaglandin E2 and IL-1 beta, although minimal levels of IL-6 and IL-8 were noted in supernatants from the gingival fibroblast cells. P. gingivalis strains BEI and NG4B19, which have either decreased or undetectable levels of trypsin-like protease, respectively, induced significantly greater IL-6 and IL-8 levels in gingival fibroblast cultures compared with the other strains. The ability of antibody to P. gingivalis to alter human gingival fibroblast production of pro-inflammatory mediators was tested using nonhuman primate antisera. Both immune and nonimmune sera altered the P. gingivalis-generated pattern of mediators from the gingival fibroblasts. We conclude that: (i) viable and killed P. gingivalis were capable of inducing various pro-inflammatory cytokines from human gingival fibroblasts; (ii) strain differences in cytokine induction were noted, and the expression of a trypsin-like protease activity was related to decreased extracellular levels of IL-6 and IL-8; and (iii) the presence of serum, particularly with specific antibody to P. gingivalis, significantly altered human gingival fibroblast cytokine production compared with P. gingivalis alone.
Collapse
Affiliation(s)
- M J Steffen
- Department of Periodontics, University of Texas Health Science Center, 7703 Floyd Curl Dr., San Antonio, TX 78284, USA
| | | | | |
Collapse
|
82
|
Abstract
If we understand pathological processess within the alimentary tract, it is apparent that the fundamental aspects of microbe-host interactions need to be examined in greater detail. Pathogenic bacteria have evolved strategies to alter and subvert the function of T cels and phagocytes in the gut wall, and exploiting these molecules may lead to new treatments for chronic inflammatory bowel diseases. The adaptation of microbes to their host must involve microbe-mediated interference of the host innate immune response. The recent demonstration that nonpathogenic E. coli have a beneficial effect in ulcerative colitis further supports the notion that normal flora may alter the expression of the innate immune receptors or recognize alternative receptors compared with pathogenic variants. Such differences may conceivably lead to beneficial and protective alterations to the host through cytokine and antimicrobial peptide expression. Perhaps the contact point between microbes and host cells lies with the pattern-recognition receptors such as TLRs. However, although much light has been shed on the downstream consequences of TLR activation, many more questions remain unsolved. For example, little is known about the expression profiles of the different TLRs throughout the gastrointestinal tract. Additionally, ambiguities remain over the natural ligands for TLRs. The discovery that the Drosophila Toll receptor acts downstream of the pathogen recognition event suggests that there are many more twists and turns to be revealed in the story of host-microbe interactions in the gastrointestinal tract.
Collapse
Affiliation(s)
- T T MacDonald
- Department of Paediatric Gastroenterology, St. Bartholomews Hospital, London, England, UK
| | | |
Collapse
|
83
|
Straube E, Knöfel B, Schneider T, Schubert S, Wetzker R. Internalization of extraintestinal Escherichia coli O18 strains by epithelial cells is modulated by EGF, insulin, and effectors of transmembrane signal transduction. Int J Med Microbiol 2000; 290:65-73. [PMID: 11043983 DOI: 10.1016/s1438-4221(00)80108-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
Abstract
Adhesion to and internalization into host cells is an essential step in the pathogenesis of various bacterial infections. Here we investigated the effects of growth factors on the internalization of Escherichia coli O18 strains isolated from patients with urinary tract infection (UTI) by human epithelial cells. A dramatic increase in the uptake of Escherichia coli was observed after treatment of epithelial cells with epidermal growth factor (EGF) and to a lower extent with insulin. EGF-dependent internalization can be suppressed by tyrosine kinase inhibitors suggesting an involvement of the receptor tyrosine kinases in the regulation of the endocytotic process. Inhibitors of phospholipase A2, lipoxygenase, and cyclooxygenase significantly decreased internalization of bacteria induced by EGF. Finally, the specific inhibitor of PI 3-kinases Wortmannin was shown to suppress completely the EGF-independent internalization. The data of this analysis indicate the involvement of several signaling paths in bacterial internalization of uropathogenic Escherichia coli O18 strains and contribute to the comprehension of the pathogenesis of recurrent UTI.
Collapse
Affiliation(s)
- E Straube
- Institut für Medizinische Mikrobiologie, Friedrich-Schiller-Universität Jena.
| | | | | | | | | |
Collapse
|
84
|
Abstract
Several recent reports show that different bacterial components trigger innate and inflammatory responses in host organisms. In parallel, selected bacterial virulence factors have been identified that interfere with corresponding responses. In many cases, this involves interference with host proinflammatory signal transduction pathways, whereas in selected cases bacterial virulence factors interfere with host antibacterial mechanisms. This indicates that bacteria, besides activating cellular responses, also have the capacity to directly interact with branches of the innate defence.
Collapse
Affiliation(s)
- M Rhen
- Microbiology and Tumor Biology Center, Karolinska Institute, Swedish Institute for Infectious Disease Control, Stockholm, Solna, 171 77, 171 82, Sweden
| | | | | |
Collapse
|
85
|
Almeida RA, Calvinho LF, Oliver SP. Influence of protein kinase inhibitors on Streptococcus uberis internalization into bovine mammary epithelial cells. Microb Pathog 2000; 28:9-16. [PMID: 10623559 DOI: 10.1006/mpat.1999.0319] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous reports indicated that bovine mammary epithelial cells internalized Streptococcus uberis, a bovine mastitis pathogen, and that inhibitors of F-actin microfilament polymerization inhibited bacterial internalization into mammary epithelial cells. In the present report, we show that inhibitors of eukaryotic cell tyrosine protein kinase (TPK) and protein kinase C (PKC), staurosporine, genistein and tyrphostin, significantly reduced internalization of S. uberis into mammary epithelial cells. Short-term treatment (15 min) of mammary epithelial cells with 12- O -tetradecanoylphorbol-13-acetate (TPA), shown previously to up-regulate activity of PKC, significantly increased internalization of S. uberis. Conversely, long-term incubation (24 h) of epithelial cells with TPA, which down-regulates PKC activity, significantly reduced the number of internalized S. uberis. These results suggest that protein kinases (TPK and PKC) are involved in internalization of S. uberis into bovine mammary epithelial cells. Identification of host cell surface receptor(s) and ligands that trigger the uptake signal by S. uberis need to be delineated.
Collapse
Affiliation(s)
- R A Almeida
- Department of Animal Science, Institute of Agriculture, Knoxville, TN, 37996, U.S.A
| | | | | |
Collapse
|
86
|
Zhang S, Wear DJ, Lo S. Mycoplasmal infections alter gene expression in cultured human prostatic and cervical epithelial cells. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2000; 27:43-50. [PMID: 10617789 DOI: 10.1111/j.1574-695x.2000.tb01410.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
To better understand how infections by mycoplasmas affect gene expression in human cells, we quantitatively measured the transcripts of 38 cytokine genes in HPV E6- and E7-immortalized cervical and prostatic epithelial cells before and after infection by four human urogenital mycoplasmas, M. fermentans, M. genitalium, M. hominis and M. penetrans. Using the multi-probe RNase protection assay (RPA), 22 and 23 cytokine gene transcripts were detected in the non-infected control prostatic and cervical epithelial cells, respectively. Although there were no discernible changes in cell morphology and growth kinetics following 72 h of mycoplasmal infection, 55-74% of the cytokine genes expressed in the two human epithelial cell lines were altered. Most changes reflected an increased expression of these cytokine genes, while expression of some cytokine genes significantly decreased. The effects varied with host cell type and species of infecting mycoplasmas. These alterations in gene expression were more profound in the cervical epithelial cells than in the prostatic cells. M. fermentans produced the most significant effects, followed by M. penetrans, M. genitalium and M. hominis. Some alterations in the gene expression were transient, but most persisted over the course of chronic (9 months) mycoplasmal infection. Prolonged gene expression changes induced by chronic mycoplasmal infection may gradually alter important biological properties in the infected mammalian cells and produce a unique form of disease process.
Collapse
Affiliation(s)
- S Zhang
- Department of Infectious and Parasitic Diseases Pathology, Washington, DC, USA.
| | | | | |
Collapse
|
87
|
Rodrigues CO, Dutra PM, Barros FS, Souto-Padrón T, Meyer-Fernandes JR, Lopes AH. Platelet-activating factor induction of secreted phosphatase activity in Trypanosoma cruzi. Biochem Biophys Res Commun 1999; 266:36-42. [PMID: 10581161 DOI: 10.1006/bbrc.1999.1759] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of platelet-activating factor (PAF) on the ecto-phosphatase activity of Trypanosoma cruzi were investigated. Living parasites hydrolyzed p-nitrophenyl phosphate (p-NPP) at a rate of 5.71 +/- 0.37 nmol P(i) mg(-1) min(-1). This ecto-phosphatase activity increased to 8.70 +/- 1.12 nmol P(i) mg(-1) min(-1) when the cells were grown in the presence of 10(-9) M PAF. This effect was probably due to stimulation of the release of the ecto-phosphatase and/or the secretion of an intracellular phosphatase to the extracellular medium, as suggested by cytochemical analysis. Modulation of the ecto-phosphatase activity was also observed when PAF was added during the time course of the reaction. WEB 2086, a competitive PAF antagonist, was able to revert PAF effects when both were used at the same concentration. When PAF was added to a membrane enriched fraction preparation of T. cruzi, no alteration on the phosphatase activity was observed. This result suggests an involvement of intracellular signaling, as PAF was only effective on intact cells. Sphingosine and phorbol-12-myristate-13-acetate (PMA) were then used to investigate a possible involvement of protein kinase C (PKC) with PAF-induced phosphatase secretion. Sphingosine by itself stimulated the secretion of a phosphatase but did not significantly interfere with PAF effects on this enzyme. On the other hand, PMA was able to abrogate PAF-induced release of this phosphatase. These data are highly suggestive of a putative involvement of signal transduction mediated by a ligand of mammalian origin (PAF), through PKC and a specific receptor located on the cell surface of the human parasite Trypanosoma cruzi.
Collapse
Affiliation(s)
- C O Rodrigues
- Instituto de Microbiologia Prof. Paulo de Góes, UFRJ, Rio de Janeiro, RJ, 21941-590, Brazil
| | | | | | | | | | | |
Collapse
|
88
|
Procópio DO, Barros HC, Mortara RA. Actin-rich structures formed during the invasion of cultured cells by infective forms of Trypanosoma cruzi. Eur J Cell Biol 1999; 78:911-24. [PMID: 10669110 DOI: 10.1016/s0171-9335(99)80093-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Previous work has shown that Trypanosoma cruzi extracellular amastigotes as well as metacyclic trypomastigotes infect cultured cells in a highly specific parasite form-cell type interaction. In this work we have investigated the mode of interaction of both forms with HeLa and Vero cells using scanning electron and confocal fluorescence microscopy. We examined the distribution of several host cell components as well as extracellular matrix elements during cell invasion by both T. cruzi infective forms. Scanning electron microscopy showed that membrane expansions formed during the invasion of cells by extracellular amastigotes. These expansions correspond to small cup-like structures in HeLa cells and are comparatively larger "crater"-like in Vero cells. We detected by confocal microscopy actin-rich structures associated with the internalisation of both infective forms of the parasite that correspond to the membrane expansions. Confocal fluorescence microscopy combining DIC images of cells labelled with monoclonal antibodies to phosphotyrosine, cytoskeletal elements, integrins, and extracellular matrix components revealed that some of the components like gelsolin and alpha-actinin accumulate in actin-rich structures formed in the invasion of amastigotes of both cell types. Others, like vinculin and alpha2 integrin may be present in these structures without evident accumulation. And finally, some actin-rich processes may be devoid of components like fibronectin or alphaV integrin. These studies provide evidence that the repertoire of host cell/extracellular matrix components that engage in the invasion process of T. cruzi forms is cell type- and parasite form-dependent.
Collapse
Affiliation(s)
- D O Procópio
- Departamento de Microbiologia, Imunologia e Parasitologia, Centro de Microscopia Eletrônica, Universidade de São Paulo, Escola Paulista de Medicina, SP, Brazil
| | | | | |
Collapse
|
89
|
Buret A, Gall DG, Olson ME, Hardin JA. The role of the epidermal growth factor receptor in microbial infections of the gastrointestinal tract. Microbes Infect 1999; 1:1139-44. [PMID: 10572318 DOI: 10.1016/s1286-4579(99)00201-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The epidermal growth factor receptor (EGFr) is a transmembrane glycoprotein with an intrinsic tyrosine kinase. Ligand-binding to the EGFr activates cell signaling, phosphorylates protein kinases, and rearranges cytoskeletal proteins - responses that resemble those induced by microbial attachment to cell surfaces, a process known to be mediated by host cell receptors in a number of cases. This article critically reviews the possible role played by the EGFr in microbial colonization, and discusses how modulation of the EGF-EGFr axis may affect infection of the gastrointestinal tract.
Collapse
Affiliation(s)
- A Buret
- Department of Biological Sciences, University of Calgary, Alberta, Canada
| | | | | | | |
Collapse
|
90
|
Hauck CR, Gulbins E, Lang F, Meyer TF. Tyrosine phosphatase SHP-1 is involved in CD66-mediated phagocytosis of Opa52-expressing Neisseria gonorrhoeae. Infect Immun 1999; 67:5490-4. [PMID: 10496937 PMCID: PMC96912 DOI: 10.1128/iai.67.10.5490-5494.1999] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/1999] [Accepted: 07/06/1999] [Indexed: 11/20/2022] Open
Abstract
Opa proteins of Neisseria gonorrhoeae bind to CD66 receptors on human phagocytes, thereby inducing efficient uptake of the bacteria in the absence of opsonins. The interaction of Opa proteins and CD66 receptors leads to activation of Src family tyrosine kinases, a process that is of critical importance for the efficient, CD66-mediated internalization. Here we show that during Opa-mediated stimulation of CD66 the activity of the host cell tyrosine phosphatase SHP-1 is strongly downregulated, concomitant with increases in the tyrosine phosphorylation of several cellular proteins. Since the SHP-1 tyrosine phosphorylation level itself is influenced by Opa-induced events, this phosphatase comprises an important regulatory checkpoint of the pathogen-triggered signaling cascade in human phagocytes.
Collapse
Affiliation(s)
- C R Hauck
- Max-Planck-Institut für Biologie, Abteilung Infektionsbiologie, Universität Tübingen, 72076 Tübingen, 10117 Berlin, Germany
| | | | | | | |
Collapse
|
91
|
Dziewanowska K, Patti JM, Deobald CF, Bayles KW, Trumble WR, Bohach GA. Fibronectin binding protein and host cell tyrosine kinase are required for internalization of Staphylococcus aureus by epithelial cells. Infect Immun 1999; 67:4673-8. [PMID: 10456915 PMCID: PMC96793 DOI: 10.1128/iai.67.9.4673-4678.1999] [Citation(s) in RCA: 201] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus expresses several surface proteins that promote adherence to host cell extracellular matrix proteins, including fibronectin (Fn). Since this organism has recently been shown to be internalized by nonprofessional phagocytes, a process that typically requires high-affinity binding to host cell receptors, we investigated the role of its Fn binding proteins (FnBPs) and other surface proteins in internalization by the bovine mammary gland epithelial cell line (MAC-T). Efficient internalization of S. aureus 8325-4 required expression of FnBPs; an isogenic mutant (DU5883), not expressing FnBPs, was reduced by more than 95% in its ability to invade MAC-T cells. Moreover, D3, a synthetic peptide derived from the ligand binding domain of FnBP, inhibited the internalization of the 8325-4 strain in a dose-dependent fashion and the efficiency of staphylococcal internalization was partially correlated with Fn binding ability. Interestingly, Fn also inhibited the internalization and adherence of S. aureus 8325-4 in a dose-dependent manner. In contrast to internalization, adherence of DU5883 to MAC-T was reduced by only approximately 40%, suggesting that surface binding proteins, other than FnBPs, can mediate bacterial adherence to cells. Adherence via these proteins, however, does not necessarily result in internalization of the staphylococci. An inhibitor of protein tyrosine kinase, genistein, reduced MAC-T internalization of S. aureus by 95%, indicating a requirement for a host signal transduction system in this process. Taken together, these results indicate that S. aureus invades nonprofessional phagocytes by a mechanism requiring interaction between FnBP and the host cell, leading to signal transduction and subsequent rearrangement of the host cell cytoskeleton.
Collapse
Affiliation(s)
- K Dziewanowska
- Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, Idaho 83844, USA
| | | | | | | | | | | |
Collapse
|
92
|
Buommino E, Morelli F, Metafora S, Rossano F, Perfetto B, Baroni A, Tufano MA. Porin from Pseudomonas aeruginosa induces apoptosis in an epithelial cell line derived from rat seminal vesicles. Infect Immun 1999; 67:4794-800. [PMID: 10456933 PMCID: PMC96811 DOI: 10.1128/iai.67.9.4794-4800.1999] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/1999] [Accepted: 05/12/1999] [Indexed: 11/20/2022] Open
Abstract
Micromolar concentrations of porin, purified from the outer membranes of Pseudomonas aeruginosa, induced in vitro the classic morphological and biochemical signs of apoptosis in an epithelial cell line (SVC1) derived from the rat seminal vesicle secretory epithelium. The programmed cell death (PCD) was p53 independent and associated with significant decrease of bcl-2 expression, a marked increase of c-myc transcriptional activity, and an absence of the mRNA coding for tissue transglutaminase. The Ca(2+) influx, caused by the porin treatment of SVC1 cells, appears to play an important role in the triggering of apoptosis in our biological model. The possibility that the porin property of inducing PCD plays a role in the infertility of individuals chronically infected by gram-negative bacteria is discussed.
Collapse
Affiliation(s)
- E Buommino
- CNR International Institute of Genetics and Biophysics, Area di Ricerca del C.N.R., Medical School, 2nd University of Naples, Italy
| | | | | | | | | | | | | |
Collapse
|
93
|
de Chastellier C, Thibon M, Rabinovitch M. Construction of chimeric phagosomes that shelter Mycobacterium avium and Coxiella burnetii (phase II) in doubly infected mouse macrophages: an ultrastructural study. Eur J Cell Biol 1999; 78:580-92. [PMID: 10494865 DOI: 10.1016/s0171-9335(99)80024-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Dual infection of cells may divert pathogens to intracellular compartments different from those occupied in mono-infected cells. In the present studies, mouse bone marrow in vitro-derived macrophages were first infected with virulent Mycobacterium avium, which are normally singly lodged within tight phagosomes. These phagosomes do not mature; they undergo homotypic fusion with early endosomes and do not fuse with lysosomes. Seven days later, the cultures were superinfected with phase II (non-virulent) Coxiella burnetii, organisms sheltered in lysosome- (or prelysosome)-like, multi-occupancy phagosomes. The latter can attain large size and engage in efficient homo- and heterotypic fusion with other phagosomes. Cultures were fixed for transmission electron microscopy 6, 12, 24, and 48 h later. Other M. avium-infected cultures were superinfected with amastigotes of the trypanosomatid flagellate Leishmania amazonensis, which are also sheltered in lysosome- (or prelysosome)-like multi-occupancy vacuoles, and fixed at the same time periods. Chimeric phagosomes containing both M. avium and C. burnetii, were found already at 6 h and the proportion of M. avium that colocalized with C. burnetii in the same phagosomes reached over 90% after 48 h. In such phagosomes, both organisms were ultrastructurally well preserved. In contrast, colocalization of M. avium and L. amazonensis was rarely found. Speculative scenarios that could underlie the formation of chimeric phagosomes could involve delayed maturation of C. burnetii-containing phagosomes in presence of M. avium, which would allow for fusion of C. burnetii- and M. avium-containing phagosomes; the production, by C. burnetii, of molecules that upregulate the fusion of M. avium-containing phagosomes with those that contain C. burnetii; and the secretion of factors that could favour the survival of M. avium within chimeric vacuoles.
Collapse
|
94
|
|
95
|
Martiny A, Meyer-Fernandes JR, de Souza W, Vannier-Santos MA. Altered tyrosine phosphorylation of ERK1 MAP kinase and other macrophage molecules caused by Leishmania amastigotes. Mol Biochem Parasitol 1999; 102:1-12. [PMID: 10477171 DOI: 10.1016/s0166-6851(99)00067-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The involvement of tyrosine phosphorylation during macrophage infection with Leishmania amazonensis amastigotes was investigated. PTK antagonists such as genistein, herbimycin A, geldanamycin and tyrphostin 25 had no significant effect on adhesion to, or entry into, murine peritoneal macrophages, but increased parasite intracellular survival. LPS-induced tyrosine phosphorylation of target host proteins assessed by immunoprecipitation and Western blot was impaired or reversed by living amastigotes soon after 60 min-infection. Such reversion was not due to parasite-secreted molecules but was contact-dependent, as assessed by cytochalasin D treatment of macrophage monolayers prior to infection. Paraformaldehyde-fixed or sodium vanadate-treated amastigotes exerted no significant effect on overall macrophage tyrosine phosphorylation. Immunoprecipitation of proteins employing 4G10 anti-phosphotyrosine antibody followed by Western blotting revealed that tyrosine phosphorylation of 120, 85, 60, 44 and 35 kDa proteins was selectively reversed by amastigote infection. Inhibition, measured by densitometry was from about 66-100% of uninfected cells. None of these proteins was immunoprecipitated from amastigote-infected macrophage lysates but all of them except for p85 were recovered after treatment of parasites with 100 microM sodium orthovanadate prior to infection, a treatment that inhibits Leishmania amastigote protein ecto-phosphatase. The 44 kDa protein was identified as ERK1 MAP kinase (MAPK) by Western blot. Amastigote infection also decreased tyrosine phosphorylation induced by zymosan particles. Vanadate treatment of amastigotes prior to infection significantly decreased parasite intracellular survival. The action of a putative leishmanial ecto-protein phosphatase (PPase) is suggested.
Collapse
Affiliation(s)
- A Martiny
- Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciênias da Saúde, Ilha do Fundão, RJ, Brazil
| | | | | | | |
Collapse
|
96
|
Griffiss JM, Lammel CJ, Wang J, Dekker NP, Brooks GF. Neisseria gonorrhoeae coordinately uses Pili and Opa to activate HEC-1-B cell microvilli, which causes engulfment of the gonococci. Infect Immun 1999; 67:3469-80. [PMID: 10377128 PMCID: PMC116533 DOI: 10.1128/iai.67.7.3469-3480.1999] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study was undertaken to examine concomitant roles of pili and colony opacity-associated proteins (Opa) in promoting Neisseria gonorrhoeae adherence to and invasion of human endometrial HEC-1-B cells. Adherence of N. gonorrhoeae to cultured HEC-1-B cells was saturable, even though organisms adhered to <50% of the cells. During 4 to 6 h of incubation, adherent mono- and diplococci formed microcolonies on the surfaces of the cells. Microvilli of the HEC-1-B cells adhered by their distal ends to individual cocci within the microcolonies. When the microcolonies grew from isogenic pilus-negative (P-) Opa-, P- Opa+, or P+ Opa- gonococci, microvilli did not elongate, and the colonies were not engulfed. In contrast, the microvilli markedly elongated during exposure to P+ Opa+ gonococci. The microvilli adhered to the organisms along their full lengths and appeared to actively participate in the engulfment of the microcolonies. Internalized microcolonies, with P+ Opa+ gonococci, contained dividing cocci and appeared to be surrounded by cell membrane but were not clearly within vacuoles. In contrast, degenerate individual organisms were within vacuoles. Low doses of chloramphenicol, which inhibits protein synthesis by both prokaryotes and eukaryotes, prevented the microvillar response to and internalization of the P+ Opa+ gonococci; higher doses caused internalization without microvillus activation. Cycloheximide and anisomycin, which inhibit only eukaryotic protein synthesis, caused dose-dependent enhancement of uptake. Cytochalasins reduced engulfment; colchicine had no effect. These results show that gonococci must express both pili and Opa to be engulfed efficiently by HEC-1-B cells.
Collapse
Affiliation(s)
- J M Griffiss
- Centre for Immunochemistry, University of California, San Francisco, California 94143, USA
| | | | | | | | | |
Collapse
|
97
|
Abstract
Signal transduction induced by receptors can elicit intracellular biochemical events that either support or inhibit cell activation. Induction of the latter has been termed "negative signaling" and can be triggered by receptors on immune cells that are distinct from activating receptors while other growth-promoting receptors induce both positive and negative signaling events. Here, the biochemistry leading to cell activation or inhibition and induced by receptors on immune cells are reviewed. Furthermore, recent experimental evidence is reviewed that indicates an important contribution of negative signaling to the intracellular survival of infectious pathogens.
Collapse
Affiliation(s)
- K M Coggeshall
- Department of Microbiology and the Comprehensive Cancer Center, Ohio State University, Columbus 43210, USA.
| |
Collapse
|
98
|
Ferrari G, Langen H, Naito M, Pieters J. A coat protein on phagosomes involved in the intracellular survival of mycobacteria. Cell 1999; 97:435-47. [PMID: 10338208 DOI: 10.1016/s0092-8674(00)80754-0] [Citation(s) in RCA: 407] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mycobacteria are intracellular pathogens that can survive within macrophage phagosomes, thereby evading host defense strategies by largely unknown mechanisms. We have identified a WD repeat host protein that was recruited to and actively retained on phagosomes by living, but not dead, mycobacteria. This protein, termed TACO, represents a component of the phagosome coat that is normally released prior to phagosome fusion with or maturation into lysosomes. In macrophages lacking TACO, mycobacteria were readily transported to lysosomes followed by their degradation. Expression of TACO in nonmacrophages prevented lysosomal delivery of mycobacteria and prolonged their intracellular survival. Active retention of TACO on phagosomes by living mycobacteria thus represents a mechanism preventing cargo delivery to lysosomes, allowing mycobacteria to survive within macrophages.
Collapse
Affiliation(s)
- G Ferrari
- Basel Institute for Immunology, Switzerland
| | | | | | | |
Collapse
|
99
|
Abstract
Phagocytosis is an uptake of large particles governed by the actin-based cytoskeleton. Binding of particles to specific cell surface receptors is the first step of phagocytosis. In higher Eucaryota, the receptors able to mediate phagocytosis are expressed almost exclusively in macrophages, neutrophils, and monocytes, conferring immunodefence properties to these cells. Receptor clustering is thought to occur upon particle binding, that in turn generates a phagocytic signal. Several pathways of phagocytic signal transduction have been identified, including the activation of tyrosine kinases and (or) serine/threonine kinase C in pivotal roles. Kinase activation leads to phosphorylation of the receptors and other proteins, recruited at the sites of phagocytosis. Monomeric GTPases of the Rho and ARF families are likely to be engaged downstream of activated receptors. The GTPases, in cooperation with phosphatidylinositol 4-phosphate 5-kinase and phosphatidylinositol 3-kinase lipid modifying enzymes, can modulate locally the assembly of the submembranous actin filament system leading to particle internalization.
Collapse
Affiliation(s)
- K Kwiatkowska
- Nencki Institute of Experimental Biology, Department of Cell Biology, Warsaw, Poland
| | | |
Collapse
|
100
|
Moss JE, Aliprantis AO, Zychlinsky A. The regulation of apoptosis by microbial pathogens. INTERNATIONAL REVIEW OF CYTOLOGY 1999; 187:203-59. [PMID: 10212981 DOI: 10.1016/s0074-7696(08)62419-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In the past few years, there has been remarkable progress unraveling the mechanism and significance of eukaryotic programmed cell death (PCD), or apoptosis. Not surprisingly, it has been discovered that numerous, unrelated microbial pathogens engage or circumvent the host's apoptotic program. In this chapter, we briefly summarize apoptosis, emphasizing those studies which assist the reader in understanding the subsequent discussion on PCD and pathogens. We then examine the relationship between virulent bacteria and apoptosis. This section is organized to reflect both common and diverse mechanisms employed by bacteria to induce PCD. A short discussion of parasites and fungi is followed by a detailed description of the interaction of viral pathogens with the apoptotic machinery. Throughout the review, apoptosis is considered within the broader contexts of pathogenesis, virulence, and host defense. Our goals are to update the reader on this rapidly expanding field and identify topics in the current literature which demand further investigation.
Collapse
Affiliation(s)
- J E Moss
- Skirball Institute of Biomolecular Medicine, New York University Medical Center, New York City 10016, USA
| | | | | |
Collapse
|