Research in P. Cossart Labor ist vom Pasteur-Institut, dem Institut National de la Santé et de la Recherche Médicale, dem Institut National de la Recherche Agronomique, ERC Advanced Grant (233348), der Agence Nationale de la Recherche (MIE-Zuschuss unterstützt SignRupVac), den Louis-Jeantet-Stiftung und der Fondation Le Roch Les Mousquetaires. AK ist ein Empfänger eines Stipendiums von den Pasteur-Universität Paris Internationale Promotionsprogramm / Institut Carnot Mala infectieuses. Wir danken Jason Mercer für die Optimierung der Zell Transfektionsprotokolls.

1. Herstellung von Zell-und Bakterienkulturen, Transfektion Werkzeuge und Primäre Antikörper <ol><li> Eine frische Agar-Platte, einzelne L. isolieren monocytogenes Kolonien aus einer bakteriellen Glycerin Lager (50% glycerol/50% gesättigte Flüssigkeit Bakterienübernachtkultur), der bei -80 ° C <ol><li> Mit einem Aluminiumgestell (bei -80 ° C gehalten), um eine gefrorene Bakterien Glycerin Lager, Streifen Bakterien auf einer Hirn-Herz-Infusion (BHI)-Agar-Platte zu transportieren. </li><li> Die Platte bei 37 ° C während 48 Stunden (oder bis einzelne Bakterienkolonien isoliert werden kann). </li><li> Bewahren Sie diese Arbeitsplatte danach bei 4 ° C während einer Zeit von maximal 1 Monat (es wird verwendet, um Flüssigkulturen zu impfen). </li><li> In unserem Protokoll, verwenden wir die L. monocytogenes-Serotyp 1/2a EGDe.PrfA * Stamm, aber wie in Fig. 1, die veranschaulicht L. monocytogenes Serotyp 4b P14.PrfA * Belastung führt zu ähnlichen Ergebnissen. </li></ol></li><li> ErLa ATCC CCL2 Zellen werden in Dulbeccos modifiziertem Eagle-Medium (DMEM) mit 10% fötalem Rinderserum (FBS) in Abwesenheit von Antibiotika, gezüchtet. </li><li> Unabhängige Pools von verschlüsselten (Kontrolle) und Anti-Met siRNAs sind in schwarz 384er-Mikroskopie Zellkulturplatten geladen. <ol><li> Verdünnen Sie 160 pmol siRNA in 500 ul RNase-freies Wasser und mit 5 ul dieser Lösung pro Well (Endkonzentration: 1,6 pmol). </li><li> Bewahren Sie diese Platte bei -20 ° C für einen Zeitraum von 1 Jahr. </li></ol></li><li> Polyklonalen Kaninchen-Antikörper gegen das bakterielle Protein InlC mit einem InlC-GST rekombinantes Protein, wie zuvor beschrieben, 25 durch Immunisierung gewonnen wurden. </li></ol> 2. Reverse-siRNA Zelltransfektion <ol><li> 72 Stunden vor der Infektion auf Raumtemperatur bringen eine schwarze 384-Well-Mikroskopie Zellkulturplatte, die 1,6 pmol siRNA in 5 ul RNase-freies Wasser in jede Vertiefung. </li><li> Zentrifugieren Sie die Platte für 3 min bei 300RCF bei Raumtemperatur bis siRNA, die in den Wänden der Vertiefungen abgelagert worden sein könnte senken. </li><li> Bereiten Raumtemperatur DMEM mit 0,4% Lipofectamine RNAiMAX ergänzt. </li><li> In 25 ul des DMEM / RNAiMAX Transfektionsmediums in jede Vertiefung (nicht die Transfektion Medium länger als 20 min inkubiert, bevor es an die siRNA). </li><li> Bewegen Sie die Platte hin und her, um die siRNA-Transfektion mit der Lösung zu mischen, dann halten Sie die Platte für 1 h bei Raumtemperatur zu ermöglichen siRNA-Lipofectamin-Komplexe zu bilden. </li><li> Wasch HeLa-Zellen aus einem konfluenten oder subkonfluenten Zellkulturflasche einmal mit 10 ml 37 ° C vorgewärmtes PBS. </li><li> Lösen HeLa-Zellen durch Zugabe von 1 ml 37 ° C vorgewärmt Trypsin zu dem Zellkulturkolben und Inkubation für 3 bis 5 min bei 37 ° C. </li><li> Re-suspend-Zellen in 10 ml 37 ° C vorgewärmten DMEM mit 16% FBS. </li><li> Zählen von Zellen und bereiten eine Zellsuspension von 12.000 Zellen pro ml in DMEM, ergänzt mit16% FBS. </li><li> Dann werden 50 ul der Zellsuspension in jede Vertiefung in der 384-Well-Platte. </li><li> Bewegen Sie die Platte schnell hin und her, um Zellen zu verteilen und lassen Zellen richten sich für 10 Minuten bei Raumtemperatur. </li><li> Verschließen Sie die Platte mit Parafilm und halten Sie sie für 72 Stunden in einem befeuchteten 5% CO 2-Atmosphäre bei 37 ° C </li></ol> 3. Zelluläre Infektion und Färbung <ol><li> Der Tag vor der Infektion, nehmen Sie eine einzelne Kolonie von L. monocytogenes von BHI-Agar-Platte und Resuspendieren in 5 ml BHI-Flüssigmedium in einem 15 ml-Polystyrolröhrchen. </li><li> Inkubieren über Nacht bei 37 ° C in einem shacking Vorrichtung für Bakterienwachstum zu ermöglichen. </li><li> Der Tag der Infektion, waschen 1 ml der über Nacht L. monocytogenes Kultur durch Zentrifugation 2 min bei 10.600 rcf auf einer Tischzentrifuge. </li><li> Verwerfen des Überstandes (der das sezernierte Cytotoxin Listeriolysin O enthält) und Resuspendieren des Pellets in 1 ml PBS (repeaT Die Waschschritt 3 mal). </li><li> Lesen des bakteriellen optische Dichte bei 600 nm war und die Anzahl von Bakterien (OD = 1 entspricht 1E9 Bakterien / ml). </li><li> Vorbereiten des angemessenen L. monocytogenes Verdünnung in DMEM mit 1% FBS: mit hochinvasiven Stämme wie EGDe.PrfA *, empfehlen wir die Verwendung von 5E4 Bakterien in 30 ul pro Well (die Vielzahl der Infektion als 25 für 2000 Zellen geschätzt). </li><li> Entfernen Sie das Zellkulturmedium in jede Vertiefung (80 ul) und ersetzen Sie es durch Zugabe von 30 ul des L. monocytogenes-haltigem Medium. </li><li> Zentrifugieren der Platte bei 200 RCF für 5 min bei Raumtemperatur auf den Infektionsprozess zu synchronisieren. </li><li> Inkubiere die Platte für 1 Stunde in einem befeuchteten 5% CO 2-Atmosphäre bei 37 ° C auf eine vorgewärmte Aluminiumblock. </li><li> Entfernen Sie die L. monocytogenes-enthaltenden Mediums aus jeder Vertiefung werden 30 &amp;mgr; l vorgewärmtem DMEM mit 10% FBS und40 ug / ml Gentamicin auf extrazelluläre L. töten monocytogenes. </li><li> Inkubation für 4 Stunden in einem 5% CO 2-Atmosphäre bei 37 ° C auf eine vorgewärmte Metallblock. </li><li> Eine Lösung von PBS mit 8% Formaldehyd (diese Lösung frisch hergestellt werden, daß die Formaldehyd-Monomere anstelle der Paraformaldehyd-Polymere, verwendet werden) ergänzt. </li><li> Ohne Verwerfen des Zellkulturmediums, füge 30 &amp;mgr; l PBS mit 8% Formaldehyd (Endkonzentration 4%) ergänzt und Inkubation für 15 min bei Raumtemperatur. </li><li> Entfernen Sie das Fixiermittel und waschen Sie die Zellen dreimal mit 80 ul PBS pro Vertiefung (halten die Zellen in einem Gesamtvolumen von 80 ul PBS pro Vertiefung). </li><li> Bereiten Sie eine 1:250 Verdünnung des Kaninchen-Anti-InlC Serum in PBS, ergänzt mit 0,2% Saponin. </li><li> Werden 10 &amp;mgr; l des primären Antikörpers in jede Vertiefung nach dem Entfernen des PBS und Inkubation für 30 min bei Raumtemperatur. </li><li> Entsorgen Sie die primärenAntikörperlösung und waschen viermal mit 40 ul PBS pro Vertiefung. </li><li> Verdünnt das sekundäre Alexa Fluor 546-gekoppelten anti-Kaninchen-Antikörper (1:250), die DAPI-Lösung (1:1500) und Phalloidin-Dy647 (1:150) in PBS, ergänzt mit 0,2% Saponin. </li><li> Werden 10 ul dieser Sekundärfärbungslösung in jede Vertiefung und Inkubation für 30 min bei Raumtemperatur. </li><li> Entsorgen Sie die sekundäre Farblösung und waschen viermal mit 40 ul PBS pro Vertiefung (Kommentar Endvolumen von 40 ul in jede Vertiefung und Abdichtung der Platte). </li><li> Die Platte kann sofort abgebildet werden oder können bei 4 ° C lichtgeschützt (mit Alufolie abdecken) für die spätere Analyse gespeichert werden. </li></ol> 4. Bild-Akquisition und Analyse <ol><li> Erwerben Sie Bilder in drei verschiedenen Kanälen (350 nm, 546 nm und 647 nm) mit einem 10X-Objektiv auf einem automatisierten Mikroskop montiert (bevorzugt erwerben 9 Bilder pro Vertiefung). </li><li> Die InlC Signal kann mit Hilfe von Bild gemessen werdenAnalyse-Software wie CellProfiler, die automatische Segmentierung der Zellkerne und Zellkörper mit der DAPI-Färbung und die Phalloidin bzw. ermöglicht. </li></ol>

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Wir haben nichts zu offenbaren.

Mehrere Parameter sind kritisch für den Erfolg unserer InlC Erfassungsprotokoll, einschließlich der Verwendung von gesunden Zellinien Anzeigen einer ausreichend großen Zytoplasma eine eindeutige Erkennung der InlC Signals zu ermöglichen. Bei dem Test in diesem Artikel schlagen wir die Verwendung von HeLa CCL2-Zellen, die sich besonders gut für unseren Test geeignet aufgrund der Erweiterung ihrer zytosolischen Raum sind wir präsentieren, andere HeLa-Klone wie HeLa-Zellen Kyoto um einen kleineren Zytoplasma kann abe...

A correction was made to <a href="http://www.jove.com/video/51043">Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes</a>. Three authors were omitted from the article at the time of publication. The acknowledgments section was also updated. The author list has been updated from:
Andreas K&#252;hbacher1,2,3, Edith Gouin1,2,3, Pascale Cossart1,2,3, Javier Pizarro-Cerd&#225;1,2,3 
1Unit&#233; des Interactions Bact&#233;ries Cellules, Pasteur Institute, 2INSERM U604, 3Institut National de la Recherche Agronomique (INRA), USC2020
to
Andreas K&#252;hbacher1,2,3, Edith Gouin1,2,3, Jason Mercer4, Mario Emmenlauer5, Christoph Dehio5, Pascale Cossart1,2,3, Javier Pizarro-Cerd&#225;1,2,3 
1Unit&#233; des Interactions Bact&#233;ries Cellules, Pasteur Institute,2INSERM U604, 3Institut National de la Recherche Agronomique (INRA), USC2020, 4Institute of Biochemistry, ETH Z&#252;rich 5Focal Area Infection Biology, Biozentrum, University of Basel
The acknowledgments where update from:
Research in P. Cossart laboratory is supported by the Pasteur Institute, the Institut National de la Sant&eacute; et de la Recherche M&eacute;dicale, the Institut National de la Recherche Agronomique, ERC Advanced Grant (233348), the Agence Nationale de la Recherche (Grant MIE-SignRupVac), the Louis-Jeantet Foundation and the Fondation Le Roch Les Mousquetaires. A.K. is a recipient of a scholarship from the Pasteur-Paris University International Doctoral Program/Institut Carnot Maladies Infectieuses. We thank Jason Mercer for optimizing the cellular transfection protocol.
to
Research in P. Cossart laboratory is supported by the Pasteur Institute, the Institut National de la Sant&eacute; et de la Recherche M&eacute;dicale, the Institut National de la Recherche Agronomique, ERC Advanced Grant (233348), the Agence Nationale de la Recherche (Grant MIE-SignRupVac), the Louis-Jeantet Foundation and the Fondation Le Roch Les Mousquetaires. A.K. is a recipient of a scholarship from the Pasteur-Paris University International Doctoral Program/Institut Carnot Maladies Infectieuses. We acknowledge support by grant 51RT 0_126008 for the Research and Technology Development (RTD) project InfectX in the frame of SystemsX.ch, the Swiss Initiative for Systems Biology (to C.D.).

A correction to author list has been made for the article Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes. Three authors were omitted from the article at the time of publication.

Erratum: Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Die Gram-positiven Bakterium Listeria monocytogenes ist ein Lebensmittel übertragbaren Krankheitserreger, der Wirtszellen eindringt, stört seine Internalisierung Vakuole und repliziert im Zytoplasma der Wirtszellen ein. L. monocytogenes Leichtigkeit der Manipulation im Labor Kontext (schnelles Wachstum, geringe Toxizität für gesunde Personen) mit dem Fortbestehen der in Zell-und Tiermodellen beobachtet bakteriellen Virulenz assoziiert (hämolytische Aktivität, Leukozytose) erlaubt seinen ersten Einsatz in den 1960er Jahren als Hauptmodell für die Untersuchung der intrazellulären Parasitismus und für die Errichtung der theoretischen Grundlagen der zellulären Immunität gegen eine Infektion 2. In den späten 1980er und frühen 1990er Jahren, die Präparation der bakteriellen intrazellulären Zyklus 3 sowie die molekulare Charakterisierung der wichtigsten bakteriellen Virulenzfaktoren 4-7 begünstigt die Verwendung von L. monocytogenes als Schlüssel molekulares Werkzeug für die Manipulation und Gestüty von Wirtszellfunktionen. Die Anwesenheit von avirulenten (L. innocua) und virulent (L. monocytogenes) Arten in der Gattung Listeria ebnete den Weg für die vergleichende Genomstudien 8, die zusammen mit der jüngsten Gründung der komplette L. monocytogenes Transkriptom 9, haben unser Verständnis der Evolution von L. erhöht monocytogenes als menschliche Krankheitserreger und als Modellsystem für die Infektion untersucht 10. L. monocytogenes induziert seine Internalisierung in Wirtszellen bei Wechselwirkung der bakteriellen Oberflächenproteinen InlA und InlB mit ihren Wirtszellrezeptoren E-Cadherin und Met, jeweils 11-12. Anfängliche Kandidat-basierten Untersuchungen führten zur Identifizierung der α / β-Actin Cateninen Verbindung als wesentliche Komponente der InlA-Invasion Kanal 13 und der Phosphoinositid-3-Kinase (PI3-K) als kritischer Effektor des InlB- abhängig Invasion cascade 14-15. Proteom-und Funktionsbasierte Assays anschließend erlaubt die Identifizierung neuer Zytoskelett-Elemente 16 und Lipid-Second Messenger 17 für Wirtszellinvasion erforderlich. Transkriptions-Studien 18 und Massenspektrometrie-basierte quantitative Proteomik 19 haben vor kurzem ein neues Licht über die Aktivierung von Signalkaskaden und Gastgeber der Unterdrückung von Immunreaktionen während L. monocytogenes-Infektion. Auf der Grundlage der Inaktivierung von großen Gruppen von Genen (kinomes, komplette Genome) von small interfering RNA Systembiologie (siRNA) Silencing haben vor kurzem neue Wege für die Analyse der globalen Wirt-Signalkaskaden im Kontext der spezifischen zellulären Funktionen, einschließlich Phagozytose geöffnet und Erreger Internalisierung 20. Genomweite siRNA-Bildschirme haben bereits durchgeführt worden, um zelluläre Kaskaden zur Infektion von L. erforderlich untersuchen monocytogenes in phagocytic Drosophila </em&gt; S2-Zellen 21-22, doch diese Art der Analyse nicht in nicht-phagozytische Zellen durchgeführt wurde, die kritische Ziele für die Infektion in vivo darstellen. Wir haben ein Protokoll für die mikroskopische Detektion der späten Stadien der Infektion durch L. optimiert monocytogenes, die für die Hochdurchsatz-siRNA-Studien von Bakterieneintrag in Epithelzellen geeignet ist. Unser Assay nutzt ein hochinvasiven L. monocytogenes-Stamm, der eine Punktmutation in PrfA, der Haupttranskriptionsregulator von L. präsentiert monocytogenes Virulenzfaktoren 6: diese Mutation (benannt PrfA *) macht PrfA konstitutiv aktiven 23 und führt zu einer erhöhten Expression der Proteine ​​Invasion InlA und InlB daher begünstigt bakterielle Eintrag in sonst schlecht nicht-infizierten Fresszellen. Unsere Auslese zur Infektion beruht auf dem Nachweis der Akkumulation des cytosolischen sezernierte bakterielle Protein InlC zugrunde: dieses Molekül isteine pleiotrope Effektor, der vorzugsweise durch intrazytoplasmatische L. exprimiert wird monocytogenes 9 und welche nimmt nicht nur in der bakteriellen Zelle-zu-Zelle verteilt 24 aber auch Wirtsimmunantwort moduliert 25. Die Fluoreszenzmarkierung InlC Sekretion von intrazellulären Bakterien ermöglicht nicht nur eine klare Unterscheidung infizierter von nicht-infizierten Zellen, sondern stellt auch eine Endpunktanzeige, die verwendet werden kann, um anschließend zu sezieren Infektion in verschiedenen Schritten: Eingabe vakuolären Flucht cytosolischen Bakterien Proliferation und Zell-zu-Zell-Ausbreitung. Dieses Mikroskopie-basiertes Protokoll kann siRNA Bildschirme gekoppelt werden daher zelluläre Signalwege bei der Infektion von Wirtszellen von L. beteiligt studieren monocytogenes.

<table border="1">
		<tbody>
		 <tr>
			<td>Name of Material/ Equipment</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments/Description</td>
		 </tr>
		 <tr>
			<td>Bacto Brain Heart Infusion</td>
			<td>BD</td>
			<td>237500</td>
			<td>For liquid BHI preparation</td>
		 </tr>
		 <tr>
			<td>Bacto Agar</td>
			<td>BD</td>
			<td>214010</td>
			<td>Supplement to liquid BHI for BHI agar plates </td>
		 </tr>
		 <tr>
			<td>Heat-Inactivated Fetal Bovine Serum</td>
			<td>Biowest</td>
			<td>51830-500</td>
			<td></td>
		 </tr>
		 <tr>
			<td>DMEM</td>
			<td>Invitrogen</td>
			<td>61965-026</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Lipofectamine RNAiMax</td>
			<td>Invitrogen</td>
			<td>13778-100</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Gentamicin</td>
			<td>Sigma </td>
			<td>G1397-10ML</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Formaldehyde (16%)</td>
			<td>EMS</td>
			<td>15710</td>
			<td>Prepare fresh before each experiment</td>
		 </tr>
		 <tr>
			<td>Anti-Rabbit Alexa Fluor 546</td>
			<td>Invitrogen</td>
			<td>A-11035</td>
			<td></td>
		 </tr>
		 <tr>
			<td>DAPI</td>
			<td>Invitrogen</td>
			<td>D-1306</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Phalloidin Dy647</td>
			<td>Dyomics</td>
			<td>647-33</td>
			<td></td>
		 </tr>
		 <tr>
			<td>siRNA Scramble</td>
			<td>Dharmacon</td>
			<td>D-001810-10</td>
			<td></td>
		 </tr>
		 <tr>
			<td>siRNA Met</td>
			<td>Dharmacon</td>
			<td>L-003156-00-0005</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Black 384-well microscopy cell culture plate</td>
			<td>Corning</td>
			<td>3985</td>
			<td></td>
		 </tr>
		 <tr>
			<td>AxioObserver Z1 microscope</td>
			<td>Zeiss</td>
			<td>431007 9901</td>
			<td></td>
		 </tr>
		 <tr>
			<td>sCMOS camera</td>
			<td>Andor</td>
			<td>Neo</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Metamorph analysis software</td>
			<td>Molecular Devices</td>
			<td>4000</td>
			<td></td>
		 </tr>
		 <tr>
			<td>CellProfiler analysis software</td>
			<td>Broad Institute</td>
			<td>Public software available at <a href="http://www.cellprofiler.org/" target="_blank">http://www.cellprofiler.org/</a></td>
			<td></td>
		 </tr>
		</tbody>
 </table>

imaging inlc secretion to investigate cellular infection by the bacterial pathogen listeria monocytogenes

Bakterienintrazelluläre Pathogene können als molekulare Werkzeuge zur zellulären Signalkaskaden auf Grund ihrer Fähigkeit, vorzüglich zu manipulieren und zu untergraben Zellfunktionen, die für die Infektion von Wirtszielgewebe erforderlich sezieren konzipiert werden. Unter diesen bakteriellen Erreger ist Listeria monocytogenes eine Gram-positiven Mikroorganismus, der als Paradigma für den intrazellulären Parasitismus in der Charakterisierung der zellulären Immunantworten verwendet wurde, und die instrumentelle Rolle in der Entdeckung der molekularen Signalwege steuern Zytoskelett-und Membrantransport Dynamik gespielt hat. In diesem Artikel beschreiben wir einen robusten mikroskopischen Assay zum Nachweis von zellulären Infektion späten Stadien von L. monocytogenes auf der Basis der Fluoreszenzmarkierung InlC, eine sekretierte bakterielle Protein, das im Cytoplasma von infizierten Zellen akkumuliert, dieser Assay für automatisierte Hochdurchsatz-small interfering RNA-Bildschirme, um char gekoppelt werdenacterize zelluläre Signalwege in der Auf-oder Abwärtsregulierung der Infektion beteiligt.

Fluoreszenzmarkierung von zytoplasmatischen InlC bietet eine robuste Anzeige für Zellinfektion durch L. monocytogenes, wie in Fig. 1 veranschaulicht: die zentrale Zelle in dem Mikrobild wird von dem Stamm P14.PrfA * 23 infiziert, wie es in dem Phasenkontrastbild (Pfeilspitzen, Fig. 1A) beobachtet werden, und es wird durch das DAPI-Signal bestätigt wird, wo einzelne Bakterien deutlich unterscheiden (Abbildung 1B). Die InlC Färbung (DAPI zum Färben...

Watch this Scientific Journal Video about Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes at JoVE.com

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Listeria monocytogenes ist ein Gram-positiven bakteriellen Erreger häufig als ein Hauptmodell für die Untersuchung der intrazellulären Parasitismus verwendet. Imaging späten L. monocytogenes-Infektion Stufen im Rahmen der kleinen interferierenden RNA Bildschirme ermöglicht die globale Untersuchung von zellulären Wege für die bakterielle Infektion von Zielwirtszellen erforderlich.

Imaging InlC Sekretion to Cellular-Infektion durch den bakteriellen Erreger untersuchen<em&gt; Listeria monocytogenes</em

Bacterial intracellular  pathogens can be conceived as molecular tools to dissect cellular signaling  cascades due to their capacity to exquisitely ...

imaging-inlc-secretion-to-investigate-cellular-infection-bacterial

Research

JoVE Journal

Immunology and Infection

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

9.8K Aufrufe.  Pasteur Institute.  Listeria monocytogenes ist ein Gram-positiven bakteriellen Erreger häufig als ein Hauptmodell für die Untersuchung der intrazellulären Parasitismus verwendet. Imaging späten L. monocytogenes-Infektion Stufen im Rahmen der kleinen interferierenden RNA Bildschirme ermöglicht die globale Untersuchung von zellulären Wege für die bakterielle Infektion von Zielwirtszellen erforderlich. 

Serie: Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice

During the 1918 influenza virus pandemic, which killed approximately 50 million people worldwide, the majority of fatalities were not the result of infection with influenza virus alone. Instead, most individuals are thought to have succumbed to a secondary bacterial infection, predominately caused by the bacterium Streptococcus pneumoniae (the pneumococcus). The synergistic relationship between infections caused by influenza virus and the pneumococcus has subsequently been observed during the 1957 Asian influenza virus pandemic, as well as during seasonal outbreaks of the virus (reviewed in 1, 2). Here, we describe a protocol used to investigate the mechanism(s) that may be involved in increased morbidity as a result of concurrent influenza A virus and S. pneumoniae infection. We have developed an infant murine model to reliably and reproducibly demonstrate the effects of influenza virus infection of mice colonised with S. pneumoniae. Using this protocol, we have provided the first insight into the kinetics of pneumococcal transmission between co-housed, neonatal mice using in vivo imaging 3.

Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice

A concurrent infection with influenza A virus is one of the factors implicated in the induction of invasive pneumococcal disease during asymptomatic Streptococcus pneumoniae carriage. Here we describe a mixed infection method using infant mice to investigate the synergism between these two respiratory pathogens.

Mit Bioluminescent Imaging, um Synergie von Untersuchen Streptococcus pneumoniae Und Influenza A Virus in Infant Mäuse

During the 1918 influenza virus pandemic, which killed approximately 50 million people worldwide, the majority of fatalities were not the result of ...

Forschung

Immunologie und Infektion

Invasion of Human Cells by a Bacterial Pathogen

Here we will describe how we study the invasion of human endothelial cells by bacterial pathogen Staphylococcus aureus . The general protocol can be applied to the study of cell invasion by virtually any culturable bacterium. The stages at which specific aspects of invasion can be studied, such as the role of actin rearrangement or caveolae, will be highlighted. Host cells are grown in flasks and when ready for use are seeded into 24-well plates containing Thermanox coverslips. Using coverslips allows subsequent removal of the cells from the wells to reduce interference from serum proteins deposited onto the sides of the wells (to which S. aureus would attach). Bacteria are grown to the required density and washed to remove any secreted proteins (e.g. toxins). Coverslips with confluent layers of endothelial cells are transferred to new 24-well plates containing fresh culture medium before the addition of bacteria. Bacteria and cells are then incubated together for the required amount of time in 5% CO2 at 37&deg;C. For S. aureus this is typically between 15-90 minutes. Thermanox coverslips are removed from each well and dip-washed in PBS to remove unattached bacteria. If total associated bacteria (adherent and internalised) are to be quantified, coverslips are then placed in a fresh well containing 0.5% Triton X-100 in PBS. Gentle pipetting leads to complete cell lysis and bacteria are enumerated by serial dilution and plating onto agar. If the number of bacteria that have invaded the cells is needed, coverslips are added to wells containing 500 &mu;l tissue culture medium supplemented with gentamicin and incubation continued for 1 h, which will kill all external bacteria. Coverslips can then be washed, cells lysed and bacteria enumerated by plating onto agar as described above. If the experiment requires direct visualisation, coverslips can be fixed and stained for light, fluorescence or confocal microscopy or prepared for electron microscopy.

A general protocol for the study of invasion of host cells by a bacterial pathogen, focusing on Staphylococcus aureus and human endothelial cells.

Invasion von menschlichen Zellen durch einen bakteriellen Erreger

Here we will describe how we study the invasion of human endothelial cells by bacterial pathogen Staphylococcus aureus . The general protocol can be ...

Measuring Bacterial Load and Immune Responses in Mice Infected with Listeria monocytogenes

Listeria monocytogenes (Listeria) is a Gram-positive facultative intracellular pathogen1. Mouse studies typically employ intravenous injection of Listeria, which results in systemic infection2. After injection, Listeria quickly disseminates to the spleen and liver due to uptake by CD8&alpha;+ dendritic cells and Kupffer cells3,4. Once phagocytosed, various bacterial proteins enable Listeria to escape the phagosome, survive within the cytosol, and infect neighboring cells5. During the first three days of infection, different innate immune cells (e.g. monocytes, neutrophils, NK cells, dendritic cells) mediate bactericidal mechanisms that minimize Listeria proliferation. CD8+ T cells are subsequently recruited and responsible for the eventual clearance of Listeria from the host, typically within 10 days of infection6.
Successful clearance of Listeria from infected mice depends on the appropriate onset of host immune responses6	. There is a broad range of sensitivities amongst inbred mouse strains7,8. Generally, mice with increased susceptibility to Listeria infection are less able to control bacterial proliferation, demonstrating increased bacterial load and/or delayed clearance compared to resistant mice. Genetic studies, including linkage analyses and knockout mouse strains, have identified various genes for which sequence variation affects host responses to Listeria infection6,8-14. Determination and comparison of infection kinetics between different mouse strains is therefore an important method for identifying host genetic factors that contribute to immune responses against Listeria. Comparison of host responses to different Listeria strains is also an effective way to identify bacterial virulence factors that may serve as potential targets for antibiotic therapy or vaccine design.
We describe here a straightforward method for measuring bacterial load (colony forming units [CFU] per tissue) and preparing single-cell suspensions of the liver and spleen for FACS analysis of immune responses in Listeria-infected mice. This method is particularly useful for initial characterization of Listeria infection in novel mouse strains, as well as comparison of immune responses between different mouse strains infected with Listeria. We use the Listeria monocytogenes EGD strain15 that, when cultured on blood agar, exhibits a characteristic halo zone around each colony due to &beta;-hemolysis1 (Figure 1). Bacterial load and immune responses can be determined at any time-point after infection by culturing tissue homogenate on blood agar plates and preparing tissue cell suspensions for FACS analysis using the protocols described below. We would note that individuals who are immunocompromised or pregnant should not handle Listeria, and the relevant institutional biosafety committee and animal facility management should be consulted before work commences.

Measuring Bacterial Load and Immune Responses in Mice Infected with Listeria monocytogenes

Listeria monocytogenes is a model organism for studying immune responses and genetic susceptibility to intracellular bacteria in mice. This method enables one to measure bacterial load and generate single-cell suspensions of the liver and spleen from mice for FACS analysis to determine changes in immune cells due to Listeria infection.

Mess-bakterielle Belastung und Immunreaktionen in Mäuse Infizierte mit Listeria monocytogenes</em

Listeria monocytogenes (Listeria) is a Gram-positive facultative intracellular pathogen1. Mouse studies typically employ intravenous injection of ...

The Insect Galleria mellonella as a Powerful Infection Model to Investigate Bacterial Pathogenesis

The study of bacterial virulence often requires a suitable animal model. Mammalian models of infection are costly and may raise ethical issues. The use of insects as infection models provides a valuable alternative. Compared to other non-vertebrate model hosts such as nematodes, insects have a relatively advanced system of antimicrobial defenses and are thus more likely to produce information relevant to the mammalian infection process. Like mammals, insects possess a complex innate immune system1. Cells in the hemolymph are capable of phagocytosing or encapsulating microbial invaders, and humoral responses include the inducible production of lysozyme and small antibacterial peptides2,3. In addition, analogies are found between the epithelial cells of insect larval midguts and intestinal cells of mammalian digestive systems. Finally, several basic components essential for the bacterial infection process such as cell adhesion, resistance to antimicrobial peptides, tissue degradation and adaptation to oxidative stress are likely to be important in both insects and mammals1. Thus, insects are polyvalent tools for the identification and characterization of microbial virulence factors involved in mammalian infections.
Larvae of the greater wax moth Galleria mellonella have been shown to provide a useful insight into the pathogenesis of a wide range of microbial infections including mammalian fungal (Fusarium oxysporum, Aspergillus fumigatus, Candida albicans) and bacterial pathogens, such as Staphylococcus aureus, Proteus vulgaris, Serratia marcescens Pseudomonas aeruginosa, Listeria monocytogenes or Enterococcus faecalis4-7. Regardless of the bacterial species, results obtained with Galleria larvae infected by direct injection through the cuticle consistently correlate with those of similar mammalian studies: bacterial strains that are attenuated in mammalian models demonstrate lower virulence in Galleria, and strains causing severe human infections are also highly virulent in the Galleria model8-11. Oral infection of Galleria is much less used and additional compounds, like specific toxins, are needed to reach mortality.
G. mellonella larvae present several technical advantages: they are relatively large (last instar larvae before pupation are about 2 cm long and weight 250 mg), thus enabling the injection of defined doses of bacteria; they can be reared at various temperatures (20 &deg;C to 30 &deg;C) and infection studies can be conducted between 15 &deg;C to above 37 &deg;C12,13, allowing experiments that mimic a mammalian environment. In addition, insect rearing is easy and relatively cheap. Infection of the larvae allows monitoring bacterial virulence by several means, including calculation of LD5014, measurement of bacterial survival15,16 and examination of the infection process17. Here, we describe the rearing of the insects, covering all life stages of G. mellonella. We provide a detailed protocol of infection by two routes of inoculation: oral and intra haemocoelic. The bacterial model used in this protocol is Bacillus cereus, a Gram positive pathogen implicated in gastrointestinal as well as in other severe local or systemic opportunistic infections18,19.

The Insect Galleria mellonella as a Powerful Infection Model to Investigate Bacterial Pathogenesis

Oral and intra haemocolic infection of larvae of the greater wax moth Galleria mellonella is described. This insect can be used to study virulence factors of entomopathogenic as well as mammalian opportunistic bacteria. Rearing of the insects, methods of infection and examples of in vivo analysis are described.

Das Insekt<em&gt; Galleria mellonella</em&gt; Als leistungsfähiges Infektion Modell zur bakterielle Pathogenität Untersuchen

The study of bacterial virulence often requires a suitable animal model. Mammalian models of infection are costly and may raise ethical issues. The use of ...

Oral Transmission of Listeria monocytogenes in Mice via Ingestion of Contaminated Food

L. monocytogenes are facultative intracellular bacterial pathogens that cause food borne infections in humans. Very little is known about the gastrointestinal phase of listeriosis due to the lack of a small animal model that closely mimics human disease. This paper describes a novel mouse model for oral transmission of L. monocytogenes. Using this model, mice fed L. monocytogenes-contaminated bread have a discrete phase of gastrointestinal infection, followed by varying degrees of systemic spread in susceptible (BALB/c/By/J) or resistant (C57BL/6) mouse strains. During the later stages of the infection, dissemination to the gall bladder and brain is observed. The food borne model of listeriosis is highly reproducible, does not require specialized skills, and can be used with a wide variety of bacterial isolates and laboratory mouse strains. As such, it is the ideal model to study both virulence strategies used by L. monocytogenes to promote intestinal colonization, as well as the host response to invasive food borne bacterial infection.

Oral Transmission of Listeria monocytogenes in Mice via Ingestion of Contaminated Food

This paper describes a novel method for oral infection of mice using Listeria monocytogenes-contaminated food. The protocol can readily be adapted for use with other food borne bacterial pathogens.

Mündliche Übertragung von<em&gt; Listeria monocytogenes</em&gt; In Mäusen über die Aufnahme von kontaminierten Speisen

L. monocytogenes are facultative intracellular bacterial pathogens that cause food borne infections in humans. Very little is known about the ...

Automated Separation of C. elegans Variably Colonized by a Bacterial Pathogen

The wormsorter is an instrument analogous to a FACS machine that is used in studies of Caenorhabditis elegans, typically to sort worms based on expression of a fluorescent reporter. Here, we highlight an alternative usage of this instrument, for sorting worms according to their degree of colonization by a GFP-expressing pathogen. This new usage allowed us to address the relationship between colonization of the worm intestine and induction of immune responses. While C. elegans immune responses to different pathogens have been documented, it is still unknown what initiates them. The two main possibilities (which are not mutually exclusive) are recognition of pathogen-associated molecular patterns, and detection of damage caused by infection. To differentiate between the two possibilities, exposure to the pathogen must be dissociated from the damage it causes. The wormsorter enabled separation of worms that were extensively-colonized by the Gram-negative pathogen Pseudomonas aeruginosa, with the damage likely caused by pathogen load, from worms that were similarly exposed, but not, or marginally, colonized. These distinct populations were used to assess the relationship between pathogen load and the induction of transcriptional immune responses. The results suggest that the two are dissociated, supporting the possibility of pathogen recognition.

Automated Separation of C. elegans Variably Colonized by a Bacterial Pathogen

The wormsorter facilitates genetic screens in Caenorhabditis elegans by sorting worms according to expression of fluorescent reporters. Here, we describe a new usage:&#160;sorting according to colonization by a GFP-expressing pathogen, and we employ it to examine the poorly understood role of pathogen recognition in initiating immune responses.

Automatische Trennung von<em&gt; C. elegans</em&gt; Variabel durch einen bakteriellen Erreger kolonisiert

The wormsorter is an instrument analogous to a FACS machine that is used in studies of Caenorhabditis elegans, typically to sort worms based on expression ...

Assessing Bacterial Invasion of Cardiac Cells in Culture and Heart Colonization in Infected Mice Using Listeria monocytogenes

Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that is capable of causing serious invasive infections in immunocompromised patients, the elderly, and pregnant women. The most common manifestations of listeriosis in humans include meningitis, encephalitis, and fetal abortion. A significant but much less documented sequelae of invasive L. monocytogenes infection involves the heart. The death rate from cardiac illness can be up to 35% despite treatment, however very little is known regarding L. monocytogenes colonization of cardiac tissue and its resultant pathologies. In addition, it has recently become apparent that subpopulations of L. monocytogenes have an enhanced capacity to invade and grow within cardiac tissue. This protocol describes in detail in vitro and in vivo methods that can be used for assessing cardiotropism of L. monocytogenes isolates. Methods are presented for the infection of H9c2 rat cardiac myoblasts in tissue culture as well as for the determination of bacterial colonization of the hearts of infected mice. These methods are useful not only for identifying strains with the potential to colonize cardiac tissue in infected animals, but may also facilitate the identification of bacterial gene products that serve to enhance cardiac cell invasion and/or drive changes in heart pathology. These methods also provide for the direct comparison of cardiotropism between multiple L. monocytogenes strains.

Assessing Bacterial Invasion of Cardiac Cells in Culture and Heart Colonization in Infected Mice Using Listeria monocytogenes

Listeria monocytogenes causes fetal infections in pregnant women and meningitis in susceptible populations. Subpopulations of bacteria can colonize cardiac tissue, causing myocarditis in patients and laboratory animals. Here we present a protocol that describes how to assess L. monocytogenes cardiac cell invasion in vitro and cardiac colonization in infected animals.

Beurteilung der bakteriellen Invasion von Herzzellen in Kultur und Herzkolonisation bei infizierten Mäusen mit Listeria monocytogenes

Listeria monocytogenes is a Gram-positive facultative intracellular pathogen that is capable of causing serious invasive infections in immunocompromised ...

RNA Purification from Intracellularly Grown Listeria monocytogenes in Macrophage Cells

Analysis of the transcriptome of bacterial pathogens during mammalian infection is a valuable tool for studying genes and factors that mediate infection. However, isolating bacterial RNA from infected cells or tissues is a challenging task, since mammalian RNA mostly dominates the lysates of infected cells. Here we describe an optimized method for RNA isolation of Listeria monocytogenes bacteria growing within bone marrow derived macrophage cells. Upon infection, cells are mildly lysed and rapidly filtered to discard most of the host proteins and RNA, while retaining intact bacteria. Next, bacterial RNA is isolated using hot phenol-SDS extraction followed by DNase treatment. The extracted RNA is suitable for gene transcription analysis by multiple techniques. This method is successfully employed in our studies of Listeria monocytogenes gene regulation during infection of macrophage cells 1-4. The protocol can be easily modified to study other bacterial pathogens and cell types.

RNA Purification from Intracellularly Grown Listeria monocytogenes in Macrophage Cells

Here we describe a method for bacterial RNA isolation from Listeria monocytogenes bacteria growing inside murine macrophages. This technique can be used with other intracellular pathogens and mammalian host cells.

RNA-Reinigung aus intrazellulär Grown<em&gt; Listeria monocytogenes</em&gt; In Makrophagenzellen

Analysis of the transcriptome of bacterial pathogens during mammalian infection is a valuable tool for studying genes and factors that mediate infection. ...

Experimental Infection with Listeria monocytogenes as a Model for Studying Host Interferon-&#947; Responses

L. monocytogenes is a gram-positive bacterium that is a cause of food borne disease in humans. Experimental infection of mice with this pathogen has been highly informative on the role of innate and adaptive immune cells and specific cytokines in host immunity against intracellular pathogens. Production of IFN-&#947; by innate cells during sublethal infection with L. monocytogenes is important for activating macrophages and early control of the pathogen1-3. In addition, IFN-&#947; production by adaptive memory lymphocytes is important for priming the activation of innate cells upon reinfection4. The L. monocytogenes infection model thus serves as a great tool for investigating whether new therapies that are designed to increase IFN-&#947; production have an impact on IFN-&#947; responses in vivo and have productive biological effects such as increasing bacterial clearance or improving mouse survival from infection. Described here is a basic protocol for how to conduct intraperitoneal infections of C57BL/6J mice with the EGD strain of L. monocytogenes and to measure IFN-&#947; production by NK cells, NKT cells, and adaptive lymphocytes by flow cytometry. In addition, procedures are described to: (1) grow and prepare the bacteria for inoculation, (2) measure bacterial load in the spleen and liver, and (3) measure animal survival to endpoints. Representative data are also provided to illustrate how this infection model can be used to test the effect of specific agents on IFN-&#947; responses to L. monocytogenes and survival of mice from this infection.

Experimental Infection with &lt;em&gt;Listeria monocytogenes&lt;/em&gt; as a Model for Studying Host Interferon-&amp;#947; Responses

This protocol describes how to inoculate C57BL/6J mice with the EGD strain of Listeria monocytogenes (L. monocytogenes) and to measure interferon-&#947; (IFN-&#947;) responses by natural killer (NK) cells, natural killer T (NKT) cells, and adaptive T lymphocytes post-infection. This protocol also describes how to conduct survival studies in mice after infection with a modified LD50 dose of the pathogen.

Experimentelle Infektion mit<em&gt; Listeria monocytogenes</em&gt; Als Modell für die Untersuchung Host-Interferon-γ Antworten

L. monocytogenes is a gram-positive bacterium that is a cause of food borne disease in humans. Experimental infection of mice with this pathogen has been ...

Listeria monocytogenes Infection of the Brain

Listeria monocytogenes is an intracellular bacterial pathogen that is frequently associated with food-borne infection. The ability of&#160;L. monocytogenes to cross the blood-brain barrier (BBB) is concerning as it can lead to life-threatening meningitis and encephalitis. The BBB protects the brain microenvironment from various toxic metabolites and microbial pathogens found in the blood following infection, and therefore supports brain homeostasis. The mechanisms by which L. monocytogenes present in the bloodstream cross the BBB to cause brain infections are not fully understood and there is also a lack of a robust model system to study brain infections by L. monocytogenes. Here, we present a simple mouse infection model to determine whether bacteria have crossed the BBB and to quantitate the burden of bacteria that have colonized the brain in vivo. In this method, animals were infected intravenously with L. monocytogenes and were humanely euthanized by exposure to CO2 followed by cervical dislocation. Cardiac perfusion of the animals was performed prior to harvesting infected organs. Blood was collected before perfusion and the number of bacteria per organ or mL of blood was determined by plating dilutions of the blood or organ homogenates on agar plates and counting the number of colonies formed. This method can be used to study novel receptor-ligand interactions that enhance infection of the brain by L. monocytogenes and can be easily adapted for the study of multiple bacterial pathogens.

Listeria monocytogenes Infection of the Brain

During infection, Listeria monocytogenes is capable of crossing the blood-brain barrier to colonize the brain. In this protocol, we demonstrate how to assess bacterial colonization of organs following infection of mice. A procedure to perform whole organ perfusion for specific determination of bacterial numbers in the brain parenchyma is provided.