101
|
Abstract
During bacterial infections a sequence of interactions occur between the pathogen and its host. Bacterial adhesion to the host cell surface is often the initial and determining step of the pathogenesis. Although experimentally adhesion is mostly studied in static conditions adhesion actually takes place in the presence of flowing liquid. First encounters between bacteria and their host often occur at the mucosal level, mouth, lung, gut, eye, etc. where mucus flows along the surface of epithelial cells. Later in infection, pathogens occasionally access the blood circulation causing life-threatening illnesses such as septicemia, sepsis and meningitis. A defining feature of these infections is the ability of these pathogens to interact with endothelial cells in presence of circulating blood. The presence of flowing liquid, mucus or blood for instance, determines adhesion because it generates a mechanical force on the pathogen. To characterize the effect of flowing liquid one usually refers to the notion of shear stress, which is the tangential force exerted per unit area by a fluid moving near a stationary wall, expressed in dynes/cm(2). Intensities of shear stress vary widely according to the different vessels type, size, organ, location etc. (0-100 dynes/cm(2)). Circulation in capillaries can reach very low shear stress values and even temporarily stop during periods ranging between a few seconds to several minutes (1). On the other end of the spectrum shear stress in arterioles can reach 100 dynes/cm(2)(2). The impact of shear stress on different biological processes has been clearly demonstrated as for instance during the interaction of leukocytes with the endothelium (3). To take into account this mechanical parameter in the process of bacterial adhesion we took advantage of an experimental procedure based on the use of a disposable flow chamber (4). Host cells are grown in the flow chamber and fluorescent bacteria are introduced in the flow controlled by a syringe pump. We initially focused our investigations on the bacterial pathogen Neisseria meningitidis, a Gram-negative bacterium responsible for septicemia and meningitis. The procedure described here allowed us to study the impact of shear stress on the ability of the bacteria to: adhere to cells (1), to proliferate on the cell surface (5)and to detach to colonize new sites (6) (Figure 1). Complementary technical information can be found in reference 7. Shear stress values presented here were chosen based on our previous experience(1) and to represent values found in the literature. The protocol should be applicable to a wide range of pathogens with specific adjustments depending on the objectives of the study.
Collapse
Affiliation(s)
- Magali Soyer
- Paris Center for Cardiovascular Research, INSERM U970
| | | |
Collapse
|
102
|
Trivedi K, Tang CM, Exley RM. Mechanisms of meningococcal colonisation. Trends Microbiol 2011; 19:456-63. [PMID: 21816616 DOI: 10.1016/j.tim.2011.06.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 06/16/2011] [Accepted: 06/28/2011] [Indexed: 01/05/2023]
Abstract
Despite advances against infectious diseases over the past century, Neisseria meningitidis remains a major causative agent of meningitis and septicaemia worldwide. Its adaptation for survival in the human nasopharynx makes the meningococcus a highly successful commensal bacterium. Recent progress has been made in understanding the mechanisms that enable neisserial colonisation, in terms of the role of type IV pili, the impact of other adhesins, biofilm formation, nutrient acquisition and resistance to host immune defences. Refinements in cell-based and in vivo models will lead to improved understanding of the colonisation process, and hopefully to more effective vaccines and therapeutic strategies.
Collapse
Affiliation(s)
- Kaushali Trivedi
- Centre for Molecular Microbiology and Infection, Faculty of Medicine, Flowers Building, Imperial College London, London SW7 2AZ, UK
| | | | | |
Collapse
|
103
|
Lepanto P, Bryant DM, Rossello J, Datta A, Mostov KE, Kierbel A. Pseudomonas aeruginosa interacts with epithelial cells rapidly forming aggregates that are internalized by a Lyn-dependent mechanism. Cell Microbiol 2011; 13:1212-22. [PMID: 21615664 DOI: 10.1111/j.1462-5822.2011.01611.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Growing evidence is pointing to the importance of multicellular bacterial structures in the interaction of pathogenic bacteria with their host. Transition from planktonic to host cell-associated multicellular structures is an essential infection step that has not been described for the opportunistic human pathogen Pseudomonas aeruginosa. In this study we show that P. aeruginosa interacts with the surface of epithelial cells mainly forming aggregates. Dynamics of aggregate formation typically follow a sigmoidal curve. First, a single bacterium attaches at cell-cell junctions. This is followed by rapid recruitment of free-swimming bacteria and association of bacterial cells resulting in the formation of an aggregate on the order of minutes. Aggregates are associated with phosphatidylinositol 3,4,5-trisphosphate (PIP3)-enriched host cell membrane protrusions. We further show that aggregates can be rapidly internalized into epithelial cells. Lyn, a member of the Src family tyrosine kinases previously implicated in P. aeruginosa infection, mediates both PIP3-enriched protrusion formation and aggregate internalization. Our results establish the first framework of principles that define P. aeruginosa transition to multicellular structures during interaction with host cells.
Collapse
Affiliation(s)
- Paola Lepanto
- Institut Pasteur de Montevideo, Montevideo 11400, Uruguay
| | | | | | | | | | | |
Collapse
|
104
|
Trimeric autotransporter adhesin-dependent adherence of Bartonella henselae, Bartonella quintana, and Yersinia enterocolitica to matrix components and endothelial cells under static and dynamic flow conditions. Infect Immun 2011; 79:2544-53. [PMID: 21536788 DOI: 10.1128/iai.01309-10] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Trimeric autotransporter adhesins (TAAs) are important virulence factors of Gram-negative bacteria responsible for adherence to extracellular matrix (ECM) and host cells. Here, we analyzed three different TAAs (Bartonella adhesin A [BadA] of Bartonella henselae, variably expressed outer membrane proteins [Vomps] of Bartonella quintana, and Yersinia adhesin A [YadA] of Yersinia enterocolitica) for mediating bacterial adherence to ECM and endothelial cells. Using static (cell culture vials) and dynamic (capillary flow chambers) experimental settings, adherence of wild-type bacteria and of the respective TAA-negative strains was analyzed. Under static conditions, ECM adherence of B. henselae, B. quintana, and Y. enterocolitica was strongly dependent on the expression of their particular TAAs. YadA of Y. enterocolitica did not mediate bacterial binding to plasma or cellular fibronectin under either static or dynamic conditions. TAA-dependent host cell adherence appeared more significant under dynamic conditions although the total number of bound bacteria was diminished compared to the number under static conditions. Dynamic models expand the methodology to perform bacterial adherence experiments under more realistic, bloodstream-like conditions and allow dissection of the biological role of TAAs in ECM and host cell adherence under static and dynamic conditions.
Collapse
|
105
|
Meningococcus Hijacks a β2-adrenoceptor/β-Arrestin pathway to cross brain microvasculature endothelium. Cell 2011; 143:1149-60. [PMID: 21183077 DOI: 10.1016/j.cell.2010.11.035] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 09/28/2010] [Accepted: 11/12/2010] [Indexed: 11/21/2022]
Abstract
Following pilus-mediated adhesion to human brain endothelial cells, meningococcus (N. meningitidis), the bacterium causing cerebrospinal meningitis, initiates signaling cascades, which eventually result in the opening of intercellular junctions, allowing meningeal colonization. The signaling receptor activated by the pathogen remained unknown. We report that N. meningitidis specifically stimulates a biased β2-adrenoceptor/β-arrestin signaling pathway in endothelial cells, which ultimately traps β-arrestin-interacting partners, such as the Src tyrosine kinase and junctional proteins, under bacterial colonies. Cytoskeletal reorganization mediated by β-arrestin-activated Src stabilizes bacterial adhesion to endothelial cells, whereas β-arrestin-dependent delocalization of junctional proteins results in anatomical gaps used by bacteria to penetrate into tissues. Activation of β-adrenoceptor endocytosis with specific agonists prevents signaling events downstream of N. meningitidis adhesion and inhibits bacterial crossing of the endothelial barrier. The identification of the mechanism used for hijacking host cell signaling machineries opens perspectives for treatment and prevention of meningococcal infection.
Collapse
|
106
|
Kostenko V, Salek MM, Sattari P, Martinuzzi RJ. Staphylococcus aureus biofilm formation and tolerance to antibiotics in response to oscillatory shear stresses of physiological levels. ACTA ACUST UNITED AC 2010; 59:421-31. [PMID: 20528928 DOI: 10.1111/j.1574-695x.2010.00694.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Bacterial infections in the blood system are usually associated with blood flow oscillation generated by some cardiovascular pathologies and insertion of indwelling devices. The influence of hydrodynamically induced shear stress fluctuations on the Staphylococcus aureus biofilm morphology and tolerance to antibiotics was investigated. Fluctuating shear stresses of physiologically relevant levels were generated in wells of a six-well microdish agitated by an orbital shaker. Numerical simulations were performed to determine the spatial distribution and local fluctuation levels of the shear stress field on the well bottom. It is found that the local biofilm deposition and morphology correlate strongly with shear stress fluctuations and maximum magnitude levels. Tolerance to killing by antibiotics correlates with morphotype and is generally higher in high shear regions.
Collapse
Affiliation(s)
- Victoria Kostenko
- Biofilm Engineering Research Group, Calgary Center for Innovative Technology, University of Calgary, Calgary, AB, Canada
| | | | | | | |
Collapse
|
107
|
Shi M, Li SS, Zheng C, Jones GJ, Kim KS, Zhou H, Kubes P, Mody CH. Real-time imaging of trapping and urease-dependent transmigration of Cryptococcus neoformans in mouse brain. J Clin Invest 2010; 120:1683-93. [PMID: 20424328 DOI: 10.1172/jci41963] [Citation(s) in RCA: 157] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Accepted: 03/03/2010] [Indexed: 11/17/2022] Open
Abstract
Infectious meningitis and encephalitis is caused by invasion of circulating pathogens into the brain. It is unknown how the circulating pathogens dynamically interact with brain endothelium under shear stress, leading to invasion into the brain. Here, using intravital microscopy, we have shown that Cryptococcus neoformans, a yeast pathogen that causes meningoencephalitis, stops suddenly in mouse brain capillaries of a similar or smaller diameter than the organism, in the same manner and with the same kinetics as polystyrene microspheres, without rolling and tethering to the endothelial surface. Trapping of the yeast pathogen in the mouse brain was not affected by viability or known virulence factors. After stopping in the brain, C. neoformans was seen to cross the capillary wall in real time. In contrast to trapping, viability, but not replication, was essential for the organism to cross the brain microvasculature. Using a knockout strain of C. neoformans, we demonstrated that transmigration into the mouse brain is urease dependent. To determine whether this could be amenable to therapy, we used the urease inhibitor flurofamide. Flurofamide ameliorated infection of the mouse brain by reducing transmigration into the brain. Together, these results suggest that C. neoformans is mechanically trapped in the brain capillary, which may not be amenable to pharmacotherapy, but actively transmigrates to the brain parenchyma with contributions from urease, suggesting that a therapeutic strategy aimed at inhibiting this enzyme could help prevent meningitis and encephalitis caused by C. neoformans infection.
Collapse
Affiliation(s)
- Meiqing Shi
- Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | | | | | | | | | | | | | | |
Collapse
|
108
|
Abstract
The human species is the only natural host of Neisseria meningitidis, an important cause of bacterial meningitis globally, and, despite its association with devastating diseases, N. meningitidis is a commensal organism found frequently in the respiratory tract of healthy individuals. To date, antibiotic resistance is relatively uncommon in N. meningitidis isolates but, due to the rapid onset of disease in susceptible hosts, the mortality rate remains approx. 10%. Additionally, patients who survive meningococcal disease often endure numerous debilitating sequelae. N. meningitidis strains are classified primarily into serogroups based on the type of polysaccharide capsule expressed. In total, 13 serogroups have been described; however, the majority of disease is caused by strains belonging to one of only five serogroups. Although vaccines have been developed against some of these, a universal meningococcal vaccine remains a challenge due to successful immune evasion strategies of the organism, including mimicry of host structures as well as frequent antigenic variation. N. meningitidis express a range of virulence factors including capsular polysaccharide, lipopolysaccharide and a number of surface-expressed adhesive proteins. Variation of these surface structures is necessary for meningococci to evade killing by host defence mechanisms. Nonetheless, adhesion to host cells and tissues needs to be maintained to enable colonization and ensure bacterial survival in the niche. The aims of the present review are to provide a brief outline of meningococcal carriage, disease and burden to society. With this background, we discuss several bacterial strategies that may enable its survival in the human respiratory tract during colonization and in the blood during infection. We also examine several known meningococcal adhesion mechanisms and conclude with a section on the potential processes that may operate in vivo as meningococci progress from the respiratory niche through the blood to reach the central nervous system.
Collapse
|
109
|
|
110
|
Abstract
The endothelium lining blood and lymphatic vessels is a key barrier separating body fluids from host tissues and is a major target of pathogenic bacteria. Endothelial cells are actively involved in host responses to infectious agents, producing inflammatory cytokines, controlling coagulation cascades and regulating leukocyte trafficking. In this Review, a range of bacteria and bacterial toxins are used to illustrate how pathogens establish intimate interactions with endothelial cells, triggering inflammatory responses and coagulation processes and modifying endothelial cell plasma membranes and junctions to adhere to their surfaces and then invade, cross and even disrupt the endothelial barrier.
Collapse
|
111
|
Zhou MY, Xie R, Yu YL, Chen G, Ju XJ, Yang L, Liang B, Chu LY. Effects of surface wettability and roughness of microchannel on flow behaviors of thermo-responsive microspheres therein during the phase transition. J Colloid Interface Sci 2009; 336:162-70. [DOI: 10.1016/j.jcis.2009.03.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 03/20/2009] [Accepted: 03/20/2009] [Indexed: 10/20/2022]
|
112
|
Neil RB, Apicella MA. Clinical and laboratory evidence for Neisseria meningitidis biofilms. Future Microbiol 2009; 4:555-63. [PMID: 19492966 DOI: 10.2217/fmb.09.27] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Neisseria meningitidis is the etiologic agent of meningococcal meningitis. Carriage of the organism is approximately 10% while active disease occurs at a rate of 1:100,000. Recent publications demonstrate that N. meningitidis has the ability to form biofilms on glass, plastic or cultured human bronchial epithelial cells. Microcolony-like structures are also observed in histological sections from patients with active meningococcal disease. This review investigates the possible role of meningococcal biofilms in carriage and active disease, based on the laboratory and clinical aspects of the disease.
Collapse
Affiliation(s)
- R Brock Neil
- University of Iowa, Hygienic Laboratory, 102 Oakdale Campus, H101 OH, Iowa City, IA 52242-5002, USA
| | | |
Collapse
|
113
|
Coureuil M, Mikaty G, Miller F, Lécuyer H, Bernard C, Bourdoulous S, Duménil G, Mège RM, Weksler BB, Romero IA, Couraud PO, Nassif X. Meningococcal type IV pili recruit the polarity complex to cross the brain endothelium. Science 2009; 325:83-7. [PMID: 19520910 DOI: 10.1126/science.1173196] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Type IV pili mediate the initial interaction of many bacterial pathogens with their host cells. In Neisseria meningitidis, the causative agent of cerebrospinal meningitis, type IV pili-mediated adhesion to brain endothelial cells is required for bacteria to cross the blood-brain barrier. Here, type IV pili-mediated adhesion of N. meningitidis to human brain endothelial cells was found to recruit the Par3/Par6/PKCzeta polarity complex that plays a pivotal role in the establishment of eukaryotic cell polarity and the formation of intercellular junctions. This recruitment leads to the formation of ectopic intercellular junctional domains at the site of bacteria-host cell interaction and a subsequent depletion of junctional proteins at the cell-cell interface with opening of the intercellular junctions of the brain-endothelial interface.
Collapse
Affiliation(s)
- Mathieu Coureuil
- Université Paris Descartes, Faculté de Médecine, INSERM (U-570), 75015 Paris, France.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
114
|
Zhou MY, Xie R, Ju XJ, Zhao ZL, Chu LY. Flow characteristics of thermo-responsive microspheres in microchannel during the phase transition. AIChE J 2009. [DOI: 10.1002/aic.11769] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
115
|
Carbonnelle E, Hill DJ, Morand P, Griffiths NJ, Bourdoulous S, Murillo I, Nassif X, Virji M. Meningococcal interactions with the host. Vaccine 2009; 27 Suppl 2:B78-89. [PMID: 19481311 DOI: 10.1016/j.vaccine.2009.04.069] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Neisseria meningitidis interacts with host tissues through hierarchical, concerted and co-ordinated actions of a number of adhesins; many of which undergo antigenic and phase variation, a strategy that helps immune evasion. Three major structures, pili, Opa and Opc predominantly influence bacterial adhesion to host cells. Pili and Opa proteins also determine host and tissue specificity while Opa and Opc facilitate efficient cellular invasion. Recent studies have also implied a role of certain adhesin-receptor pairs in determining increased host susceptibility to infection. This chapter examines our current knowledge of meningococcal adhesion and invasion mechanisms particularly related to human epithelial and endothelial cells which are of primary importance in the disease process.
Collapse
Affiliation(s)
- Etienne Carbonnelle
- INSERM, unité 570, Université Paris Descartes, 156 rue de Vaugirard, Paris 75015, France
| | | | | | | | | | | | | | | |
Collapse
|
116
|
|
117
|
Dual role for pilus in adherence to epithelial cells and biofilm formation in Streptococcus agalactiae. PLoS Pathog 2009; 5:e1000422. [PMID: 19424490 PMCID: PMC2674936 DOI: 10.1371/journal.ppat.1000422] [Citation(s) in RCA: 174] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 04/09/2009] [Indexed: 01/08/2023] Open
Abstract
Streptococcus agalactiae is a common human commensal and a major life-threatening pathogen in neonates. Adherence to host epithelial cells is the first critical step of the infectious process. Pili have been observed on the surface of several gram-positive bacteria including S. agalactiae. We previously characterized the pilus-encoding operon gbs1479-1474 in strain NEM316. This pilus is composed of three structural subunit proteins: Gbs1478 (PilA), Gbs1477 (PilB), and Gbs1474 (PilC), and its assembly involves two class C sortases (SrtC3 and SrtC4). PilB, the bona fide pilin, is the major component; PilA, the pilus associated adhesin, and PilC, are both accessory proteins incorporated into the pilus backbone. We first addressed the role of the housekeeping sortase A in pilus biogenesis and showed that it is essential for the covalent anchoring of the pilus fiber to the peptidoglycan. We next aimed at understanding the role of the pilus fiber in bacterial adherence and at resolving the paradox of an adhesive but dispensable pilus. Combining immunoblotting and electron microscopy analyses, we showed that the PilB fiber is essential for efficient PilA display on the surface of the capsulated strain NEM316. We then demonstrated that pilus integrity becomes critical for adherence to respiratory epithelial cells under flow-conditions mimicking an in vivo situation and revealing the limitations of the commonly used static adherence model. Interestingly, PilA exhibits a von Willebrand adhesion domain (VWA) found in many extracellular eucaryotic proteins. We show here that the VWA domain of PilA is essential for its adhesive function, demonstrating for the first time the functionality of a prokaryotic VWA homolog. Furthermore, the auto aggregative phenotype of NEM316 observed in standing liquid culture was strongly reduced in all three individual pilus mutants. S. agalactiae strain NEM316 was able to form biofilm in microtiter plate and, strikingly, the PilA and PilB mutants were strongly impaired in biofilm formation. Surprisingly, the VWA domain involved in adherence to epithelial cells was not required for biofilm formation.
Collapse
|
118
|
Affiliation(s)
- Simone Lepper
- Department of Parasitology, Hygiene Institute, University of Heidelberg Medical School, 69120 Heidelberg, Germany
| | | |
Collapse
|
119
|
Mikaty G, Soyer M, Mairey E, Henry N, Dyer D, Forest KT, Morand P, Guadagnini S, Prévost MC, Nassif X, Duménil G. Extracellular bacterial pathogen induces host cell surface reorganization to resist shear stress. PLoS Pathog 2009; 5:e1000314. [PMID: 19247442 PMCID: PMC2642725 DOI: 10.1371/journal.ppat.1000314] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Accepted: 01/26/2009] [Indexed: 12/30/2022] Open
Abstract
Bacterial infections targeting the bloodstream lead to a wide array of devastating diseases such as septic shock and meningitis. To study this crucial type of infection, its specific environment needs to be taken into account, in particular the mechanical forces generated by the blood flow. In a previous study using Neisseria meningitidis as a model, we observed that bacterial microcolonies forming on the endothelial cell surface in the vessel lumen are remarkably resistant to mechanical stress. The present study aims to identify the molecular basis of this resistance. N. meningitidis forms aggregates independently of host cells, yet we demonstrate here that cohesive forces involved in these bacterial aggregates are not sufficient to explain the stability of colonies on cell surfaces. Results imply that host cell attributes enhance microcolony cohesion. Microcolonies on the cell surface induce a cellular response consisting of numerous cellular protrusions similar to filopodia that come in close contact with all the bacteria in the microcolony. Consistent with a role of this cellular response, host cell lipid microdomain disruption simultaneously inhibited this response and rendered microcolonies sensitive to blood flow–generated drag forces. We then identified, by a genetic approach, the type IV pili component PilV as a triggering factor of plasma membrane reorganization, and consistently found that microcolonies formed by a pilV mutant are highly sensitive to shear stress. Our study shows that bacteria manipulate host cell functions to reorganize the host cell surface to form filopodia-like structures that enhance the cohesion of the microcolonies and therefore blood vessel colonization under the harsh conditions of the bloodstream. Certain infectious agents reach the bloodstream and succeed in surviving and multiplying at this site. This stage of the infection is associated with a life-threatening condition. The Gram-negative bacterium meningococcus, responsible for septicemia and meningitis, stands out as a paradigm of such a pathogen. Despite the characteristic flow-generated hydrodynamic forces of the bloodstream, meningococci have the striking ability to bind to the endothelium and to multiply in bacterial aggregates called microcolonies. Meningococci form aggregates in absence of eukaryotic cells, but we show that such aggregates are sensitive to mechanical stress, indicating that the presence of host cells enhances microcolony cohesion. Consistently, analysis of meningococcal microcolonies growing on the host cellular surface reveals that these structures are dense with cellular material in the form of cellular protrusions. Blocking this bacteria-induced cellular response renders microcolonies sensitive to blood flow. We then identify a bacterial component located on the outside of the bacteria and in direct contact with host cells as a key factor in the induction of this cellular response. This bacteria-induced cellular response is therefore a striking example of how pathogens exploit cellular functions as a survival strategy, in this case in the particular context of the bloodstream.
Collapse
Affiliation(s)
- Guillain Mikaty
- INSERM, U570, Paris, France
- Université Paris Descartes, Faculté de Médecine Paris Descartes, UMR S570, Paris, France
| | - Magali Soyer
- INSERM, U570, Paris, France
- Université Paris Descartes, Faculté de Médecine Paris Descartes, UMR S570, Paris, France
| | - Emilie Mairey
- INSERM, U570, Paris, France
- Université Paris Descartes, Faculté de Médecine Paris Descartes, UMR S570, Paris, France
| | | | - Dave Dyer
- University of Wisconsin-Madison, Department of Bacteriology, Madison, Wisconsin, United States of America
| | - Katrina T. Forest
- University of Wisconsin-Madison, Department of Bacteriology, Madison, Wisconsin, United States of America
| | - Philippe Morand
- INSERM, U570, Paris, France
- Université Paris Descartes, Faculté de Médecine Paris Descartes, UMR S570, Paris, France
| | | | | | - Xavier Nassif
- INSERM, U570, Paris, France
- Université Paris Descartes, Faculté de Médecine Paris Descartes, UMR S570, Paris, France
- AP-HP, Hôpital Necker-Enfants Malades, Paris, France
| | - Guillaume Duménil
- INSERM, U570, Paris, France
- Université Paris Descartes, Faculté de Médecine Paris Descartes, UMR S570, Paris, France
- * E-mail:
| |
Collapse
|
120
|
Poller B, Gutmann H, Krähenbühl S, Weksler B, Romero I, Couraud PO, Tuffin G, Drewe J, Huwyler J. The human brain endothelial cell line hCMEC/D3 as a human blood-brain barrier model for drug transport studies. J Neurochem 2008; 107:1358-68. [PMID: 19013850 DOI: 10.1111/j.1471-4159.2008.05730.x] [Citation(s) in RCA: 220] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The human brain endothelial capillary cell line hCMEC/D3 has been developed recently as a model for the human blood-brain barrier. In this study a further characterization of this model was performed with special emphasis on permeability properties and active drug transport. Para- or transcellular permeabilities (P(e)) of inulin (0.74 x 10(-3) cm/min), sucrose (1.60 x 10(-3) cm/min), lucifer yellow (1.33 x 10(-3) cm/min), morphine (5.36 x 10(-3) cm/min), propranolol (4.49 x 10(-3) cm/min) and midazolam (5.13 x 10(-3) cm/min) were measured. By addition of human serum the passive permeability of sucrose could be reduced significantly by up to 39%. Furthermore, the expression of a variety of drug transporters (ABCB1, ABCG2, ABCC1-5) as well as the human transferrin receptor was demonstrated on the mRNA level. ABCB1, ABCG2 and transferrin receptor proteins were detected and functional activity of ABCB1, ABCG2 and the ABCC family was quantified in efflux experiments. Furthermore, ABCB1-mediated bidirectional transport of rhodamine 123 was studied. The transport rate from the apical to the basolateral compartment was significantly lower than that in the inverse direction, indicating directed p-glycoprotein transport. The results of this study demonstrate the usefulness of the hCMEC/D3 cell line as an in vitro model to study drug transport at the level of the human blood-brain barrier.
Collapse
Affiliation(s)
- Birk Poller
- Department of Clinical Pharmacology and Toxicology, University Hospital of Basel, Basel, Switzerland
| | | | | | | | | | | | | | | | | |
Collapse
|
121
|
Abstract
Central nervous system (CNS) infections continue to be an important cause of morbidity and mortality. Microbial invasion and traversal of the blood-brain barrier is a prerequisite for CNS infections. Pathogens can cross the blood-brain barrier transcellularly, paracellularly and/or in infected phagocytes (the so-called Trojan-horse mechanism). Consequently, pathogens can cause blood-brain barrier dysfunction, including increased permeability, pleocytosis and encephalopathy. A more complete understanding of the microbial-host interactions that are involved in microbial traversal of the blood-brain barrier and the associated barrier dysfunction should help to develop new strategies to prevent CNS infections.
Collapse
|
122
|
Anderson EJ, Knothe Tate ML. Open access to novel dual flow chamber technology for in vitro cell mechanotransduction, toxicity and pharamacokinetic studies. Biomed Eng Online 2007; 6:46. [PMID: 18053207 PMCID: PMC2235874 DOI: 10.1186/1475-925x-6-46] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Accepted: 12/04/2007] [Indexed: 11/10/2022] Open
Abstract
Background A major stumbling block for researchers developing experimental models of mechanotransduction is the control of experimental variables, in particular the transmission of the mechanical forces at the cellular level. A previous evaluation of state of the art commercial perfusion chambers showed that flow regimes, applied to impart a defined mechanical stimulus to cells, are poorly controlled and that data from studies in which different chambers are utilized can not be compared, even if the target stress regimes are comparable. Methods This study provides a novel chamber design to provide both physiologically-based flow regimes, improvements in control of experimental variables, as well as ease of use compared to commercial chambers. This novel design achieves controlled stresses through five gasket designs and both single- and dual-flow regimes. Results The imparted shear stress within the gasket geometry is well controlled. Fifty percent of the entire area of the 10 × 21 mm universal gasket (Gasket I, designed to impart constant magnitude shear stresses in the center of the chamber where outcome measures are taken), is exposed to target stresses. In the 8 mm diameter circular area at the center of the chamber (where outcome measures are made), over 92% of the area is exposed to the target stress (± 2.5%). In addition, other gasket geometries provide specific gradients of stress that vary with distance from the chamber inlet. Bench-top testing of the novel chamber prototype shows improvements, in the ease of use as well as in performance, compared to the other commercial chambers. The design of the chamber eliminates flow deviations due to leakage and bubbles and allows actual flow profiles to better conform with those predicted in computational models. Conclusion The novel flow chamber design provides predictable and well defined mechanical forces at the surface of a cell monolayer, showing improvement over previously tested commercial chambers. The predictability of the imparted stress improves both experiment repeatability as well as the accuracy of inter-study comparisons. Carefully controlling the stresses on cells is critical in effectively mimicking in vivo situations. Overall, the improved perfusion flow chamber provides the needed resolution, standardization and in vitro model analogous to in vivo conditions to make the step towards greater use in research and the opportunity to enter the diagnostic and therapeutic market.
Collapse
Affiliation(s)
- Eric J Anderson
- Department of Mechanical & Aerospace Engineering, Case Western Reserve University, Cleveland, OH, USA.
| | | |
Collapse
|
123
|
Chamot-Rooke J, Rousseau B, Lanternier F, Mikaty G, Mairey E, Malosse C, Bouchoux G, Pelicic V, Camoin L, Nassif X, Duménil G. Alternative Neisseria spp. type IV pilin glycosylation with a glyceramido acetamido trideoxyhexose residue. Proc Natl Acad Sci U S A 2007; 104:14783-8. [PMID: 17804791 PMCID: PMC1976187 DOI: 10.1073/pnas.0705335104] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The importance of protein glycosylation in the interaction of pathogenic bacteria with their host is becoming increasingly clear. Neisseria meningitidis, the etiological agent of cerebrospinal meningitis, crosses cellular barriers after adhering to host cells through type IV pili. Pilin glycosylation genes (pgl) are responsible for the glycosylation of PilE, the major subunit of type IV pili, with the 2,4-diacetamido-2,4,6-trideoxyhexose residue. Nearly half of the clinical isolates, however, display an insertion in the pglBCD operon, which is anticipated to lead to a different, unidentified glycosylation. Here the structure of pilin glycosylation was determined in such a strain by "top-down" MS approaches. MALDI-TOF, nanoelectrospray ionization Fourier transform ion cyclotron resonance, and nanoelectrospray ionization quadrupole TOF MS analysis of purified pili preparations originating from N. meningitidis strains, either wild type or deficient for pilin glycosylation, revealed a glycan mass inconsistent with 2,4-diacetamido-2,4,6-trideoxyhexose or any sugar in the databases. This unusual modification was determined by in-source dissociation of the sugar from the protein followed by tandem MS analysis with collision-induced fragmentation to be a hexose modified with a glyceramido and an acetamido group. We further show genetically that the nature of the sugar present on the pilin is determined by the carboxyl-terminal region of the pglB gene modified by the insertion in the pglBCD locus. We thus report a previously undiscovered monosaccharide involved in posttranslational modification of type IV pilin subunits by a MS-based approach and determine the molecular basis of its biosynthesis.
Collapse
Affiliation(s)
- Julia Chamot-Rooke
- *Ecole Polytechnique, Laboratoire des Mécanismes Réactionnels, Département de Chimie, F-91128 Palaiseau, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7651, F-91128 Paris, France
| | - Benoit Rousseau
- Institut National de la Santé et de la Recherche Médicale, Unité 570, F-75015 Paris, France
- Université René Descartes, Faculté de Médecine René Descartes, F-75006 Paris, France
| | - Fanny Lanternier
- Institut National de la Santé et de la Recherche Médicale, Unité 570, F-75015 Paris, France
- Université René Descartes, Faculté de Médecine René Descartes, F-75006 Paris, France
| | - Guillain Mikaty
- Institut National de la Santé et de la Recherche Médicale, Unité 570, F-75015 Paris, France
- Université René Descartes, Faculté de Médecine René Descartes, F-75006 Paris, France
| | - Emilie Mairey
- Institut National de la Santé et de la Recherche Médicale, Unité 570, F-75015 Paris, France
- Université René Descartes, Faculté de Médecine René Descartes, F-75006 Paris, France
| | - Christian Malosse
- *Ecole Polytechnique, Laboratoire des Mécanismes Réactionnels, Département de Chimie, F-91128 Palaiseau, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7651, F-91128 Paris, France
| | - Guy Bouchoux
- *Ecole Polytechnique, Laboratoire des Mécanismes Réactionnels, Département de Chimie, F-91128 Palaiseau, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7651, F-91128 Paris, France
| | - Vladimir Pelicic
- Institut National de la Santé et de la Recherche Médicale, Unité 570, F-75015 Paris, France
- Université René Descartes, Faculté de Médecine René Descartes, F-75006 Paris, France
| | - Luc Camoin
- Université René Descartes, Faculté de Médecine René Descartes, F-75006 Paris, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8104, F-75014 Paris, France
- **Institut Cochin, Département de Biologie Cellulaire, F-75014 Paris, France
- Institut National de la Santé et de la Recherche Médicale, Unité 567, F-75014 Paris, France; and
| | - Xavier Nassif
- Institut National de la Santé et de la Recherche Médicale, Unité 570, F-75015 Paris, France
- Université René Descartes, Faculté de Médecine René Descartes, F-75006 Paris, France
- Assistance Publique–Hôpitaux de Paris, Hôpital Necker–Enfants Malades, F-75015 Paris, France
| | - Guillaume Duménil
- Institut National de la Santé et de la Recherche Médicale, Unité 570, F-75015 Paris, France
- Université René Descartes, Faculté de Médecine René Descartes, F-75006 Paris, France
- To whom correspondence should be addressed. E-mail:
| |
Collapse
|
124
|
Behling-Kelly E, Czuprynski CJ. Endothelial cells as active participants in veterinary infections and inflammatory disorders. Anim Health Res Rev 2007; 8:47-58. [PMID: 17692142 DOI: 10.1017/s1466252307001296] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AbstractEndothelial cells were once viewed as relatively inert cells lining the vasculature. They are now recognized as active and responsive regulators of coagulation, platelet adhesion, fluid homeostasis, wound healing, leukocyte extravasation and vascular tone. Endothelial cells play a key role in the host response to infectious agents by regulating leukocyte trafficking, producing inflammatory cytokines and presenting antigen in association with major histocompatibility class II (MHC II) molecules. A number of infectious agents have a tropism for endothelial cells. Infection of endothelial cells can promote thrombosis, vascular leakage, and increased adherence and emigration of leukocytes. Furthermore, activation of a systemic inflammatory response, in the absence of direct endothelial cell infection, can also lead to endothelial cell dysfunction. The purpose of this review is to highlight the interactions between endothelial cells and infectious or inflammatory agents that contribute to coagulation disturbances, vasculitis and edema. A select group of viral and bacterial pathogens will be used as examples to demonstrate how endothelial cell dysfunction contributes to the pathogenesis of infectious and inflammatory disorders.
Collapse
Affiliation(s)
- E Behling-Kelly
- Department of Pathobiological Sciences, University of Wisconsin, School of Veterinary Medicine, 2015 Linden Drive, Madsion, WI 53706, USA
| | | |
Collapse
|
125
|
Higashi DL, Lee SW, Snyder A, Weyand NJ, Bakke A, So M. Dynamics of Neisseria gonorrhoeae attachment: microcolony development, cortical plaque formation, and cytoprotection. Infect Immun 2007; 75:4743-53. [PMID: 17682045 PMCID: PMC2044525 DOI: 10.1128/iai.00687-07] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Neisseria gonorrhoeae is the bacterium that causes gonorrhea, a major sexually transmitted disease and a significant cofactor for human immunodeficiency virus transmission. The retactile N. gonorrhoeae type IV pilus (Tfp) mediates twitching motility and attachment. Using live-cell microscopy, we reveal for the first time the dynamics of twitching motility by N. gonorrhoeae in its natural environment, human epithelial cells. Bacteria aggregate into microcolonies on the cell surface and induce a massive remodeling of the microvillus architecture. Surprisingly, the microcolonies are motile, and they fuse to form progressively larger structures that undergo rapid reorganization, suggesting that bacteria communicate with each other during infection. As reported, actin plaques form beneath microcolonies. Here, we show that cortical plaques comigrate with motile microcolonies. These activities are dependent on pilT, the Tfp retraction locus. Cultures infected with a pilT mutant have significantly higher numbers of apoptotic cells than cultures infected with the wild-type strain. Inducing pilT expression with isopropyl-beta-D-thiogalactopyranoside partially rescues cells from infection-induced apoptosis, demonstrating that Tfp retraction is intrinsically cytoprotective for the host. Tfp-mediated attachment is therefore a continuum of microcolony motility and force stimulation of host cell signaling, leading to a cytoprotective effect.
Collapse
Affiliation(s)
- Dustin L Higashi
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd., Portland, Oregon 97239, USA
| | | | | | | | | | | |
Collapse
|
126
|
Mairey E, Genovesio A, Donnadieu E, Bernard C, Jaubert F, Pinard E, Seylaz J, Olivo-Marin JC, Nassif X, Duménil G. Cerebral microcirculation shear stress levels determine Neisseria meningitidis attachment sites along the blood–brain barrier. J Biophys Biochem Cytol 2006. [DOI: 10.1083/jcb1744oia7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|