Name: imaging inlc secretion to investigate cellular infection by the bacterial pathogen listeria monocytogenes
Uploaded: 2013-09-19T22:00:00
Description: Watch this Scientific Journal Video about Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes at JoVE.com

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.).

1. Preparation of Cellular and Bacterial Cultures, Transfection Tools and Primary Antibodies
<ol>
	<li>Prepare a fresh agar plate to isolate individual L. monocytogenes colonies from a bacterial glycerol stock (50% glycerol/50% saturated bacterial liquid overnight culture) kept at -80 &#176;C.
	<ol>
		<li>Using an aluminum rack (kept at -80 &#176;C) to transport a frozen bacterial glycerol stock, streak bacteria on a Brain Heart Infusion (BHI) agar plate.</li>
		<li>Incubate the plate at 37 &#176;C during 48 h...

<ol>
	<li>Pizarro-Cerd&#225;, J., K&#252;hbacher, A., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Entry+of+Listeria+monocytogenes+in+mammalian+epithelial+cells:+an+updated+view.">Entry of Listeria monocytogenes in mammalian epithelial cells: an updated view.</a> Cold Spring Harbor Perspectives in Medicine. 2, 1-17 (2012).</li><li>Mackaness, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+resistance+to+infection.">Cellular resistance to infection.</a> Journal of Experimental Medicine. 116, 381-406 (1962).</li><li>Tilney, L. G., Portnoy, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Actin+filaments+and+the+growth,+movement,+and+spread+of+the+intracellular+bacterial+parasite,+Listeria+monocytogenes.">Actin filaments and the growth, movement, and spread of the intracellular bacterial parasite, Listeria monocytogenes.</a> Journal of Cell Biology. 109, 1597-1608 (1989).</li><li>Mengaud, J., Chenevert, J., Geoffroy, C., Gaillard, J. L., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+the+structural+gene+encoding+the+SH-activated+hemolysin+of+Listeria+monocytogenes:+listeriolysin+O+is+homologous+to+streptolysin+O+and+pneumolysin.">Identification of the structural gene encoding the SH-activated hemolysin of Listeria monocytogenes: listeriolysin O is homologous to streptolysin O and pneumolysin.</a> Infection and Immunity. 55, 3225-3227 (1987).</li><li>Gaillard, J. L., Berche, P., Frehel, C., Gouin, E., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Entry+of+L.+monocytogenes+into+cells+is+mediated+by+internalin,+a+repeat+protein+reminiscent+of+surface+antigens+from+gram-positive+cocci.">Entry of L. monocytogenes into cells is mediated by internalin, a repeat protein reminiscent of surface antigens from gram-positive cocci.</a> Cell. 65, 1127-1141 (1991).</li><li>Mengaud, J., Dramsi, S., Gouin, E., Vazquez-Boland, J. A., Milon, G., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pleiotropic+control+of+Listeria+monocytogenes+virulence+factors+by+a+gene+that+is+autoregulated.">Pleiotropic control of Listeria monocytogenes virulence factors by a gene that is autoregulated.</a> Molecular Microbiology. 5, 2273-2283 (1991).</li><li>Kocks, C., Gouin, E., Tabouret, M., Berche, P., Ohayon, H., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=L.+monocytogenes-induced+actin+assembly+requires+the+actA+gene+product,+a+surface+protein.">L. monocytogenes-induced actin assembly requires the actA gene product, a surface protein.</a> Cell. 68, 521-52 (1992).</li><li>Glaser, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+genomics+of+Listeria+species.">Comparative genomics of Listeria species.</a> Science. 294, 849-852 (2001).</li><li>Toledo-Arana, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Listeria+transcriptional+landscape:+from+saprophytism+to+virulence.">The Listeria transcriptional landscape: from saprophytism to virulence.</a> Nature. 459, 950-956 (2009).</li><li>Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Illuminating+the+landscape+of+host-pathogen+interactions+with+the+bacterium+Listeria+monocytogenes.">Illuminating the landscape of host-pathogen interactions with the bacterium Listeria monocytogenes.</a> Proceedings of the National Academy of Sciences USA. 108, 19484-19491 (1073).</li><li>Mengaud, J., Ohayon, H., Gounon, P., Mege, R. -. M., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=E-cadherin+is+the+receptor+for+internalin,+a+surface+protein+required+for+entry+of+L.+monocytogenes+into+epithelial+cells.">E-cadherin is the receptor for internalin, a surface protein required for entry of L. monocytogenes into epithelial cells.</a> Cell. 84, 923-932 (1996).</li><li>Shen, Y., Naujokas, M., Park, M., Ireton, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=InIB-dependent+internalization+of+Listeria+is+mediated+by+the+Met+receptor+tyrosine+kinase.">InIB-dependent internalization of Listeria is mediated by the Met receptor tyrosine kinase.</a> Cell. 103, 501-510 (2000).</li><li>Lecuit, M., Hurme, R., Pizarro-Cerda, J., Ohayon, H., Geiger, B., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+role+for+alpha-and+beta-catenins+in+bacterial+uptake.">A role for alpha-and beta-catenins in bacterial uptake.</a> Proceedings of the National Academy of Sciences USA. 97, 10008-10013 (2000).</li><li>Ireton, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+role+for+phosphoinositide+3-kinase+in+bacterial+invasion.">A role for phosphoinositide 3-kinase in bacterial invasion.</a> Science. 274, 780-782 (1996).</li><li>Ireton, K., Payrastre, B., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Listeria+monocytogenes+protein+InlB+is+an+agonist+of+mammalian+phosphoinositide+3-kinase.">The Listeria monocytogenes protein InlB is an agonist of mammalian phosphoinositide 3-kinase.</a> Journal of Biological Chemistry. 274, 17025-17032 (1999).</li><li>Pizarro-Cerd&#225;, J., Jonqui&#232;res, R., Gouin, E., Vandekerckhove, J., Garin, J., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Distinct+protein+patterns+associated+with+Listeria+monocytogenes+InlA-+or+InlB+phagosomes.">Distinct protein patterns associated with Listeria monocytogenes InlA- or InlB phagosomes.</a> Cellular Microbiology. 4, 101-115 (2002).</li><li>Pizarro-Cerd&#225;, J., Payrastre, B., Wang, Y. -. J., Veiga, E., Yin, H. L., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Type+II+phosphatidylinositol+4-kinases+promote+Listeria+monocytogenes+entry+into+target+cells.">Type II phosphatidylinositol 4-kinases promote Listeria monocytogenes entry into target cells.</a> Cellular Microbiology. 9, 2381-2390 (2007).</li><li>Hamon, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histone+modifications+induced+by+a+family+of+bacterial+toxins.">Histone modifications induced by a family of bacterial toxins.</a> Proceedings of the National Academy of Sciences USA. 104, 17555-17559 (2007).</li><li>Ribet, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Listeria+monocytogenes+impairs+SUMOylation+for+efficient+infection.">Listeria monocytogenes impairs SUMOylation for efficient infection.</a> Nature. 464, 1192-1195 (2010).</li><li>R&#228;met, M., Manfruelli, P., Pearson, A., Mathey-Prevot, B., Ezekowitz, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+genomic+analysis+of+phagocytosis+and+identification+of+a+Drosophila+receptor+for+E.+coli.">Functional genomic analysis of phagocytosis and identification of a Drosophila receptor for E. coli.</a> Nature. 416, 644-648 (2002).</li><li>Agaisse, H., Burrack, L. S., Philips, J. A., Rubin, E. J., Perrimon, N., Higgins, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-wide+RNAi+screen+for+host+factors+required+for+intracellular+bacterial+infection.">Genome-wide RNAi screen for host factors required for intracellular bacterial infection.</a> Science. 309, 1248-1251 (2005).</li><li>Cheng, L. W., Viala, J. P., Stuurman, N., Wiedemann, U., Vale, R. D., Portnoy, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+RNA+interference+in+Drosophila+S2+cells+to+identify+host+pathways+controlling+compartmentalization+of+an+intracellular+pathogen.">Use of RNA interference in Drosophila S2 cells to identify host pathways controlling compartmentalization of an intracellular pathogen.</a> Proceedings of the National Academy of Sciences USA. 102, 13646-13651 (2005).</li><li>Ripio, M. T., Dom&#237;nguez-Bernal, G., Lara, M., Su&#225;rez, M., Vazquez-Boland, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Gly145Ser+substitution+in+the+transcriptional+activator+PrfA+causes+constitutive+overexpression+of+virulence+factors+in+Listeria+monocytogenes.">A Gly145Ser substitution in the transcriptional activator PrfA causes constitutive overexpression of virulence factors in Listeria monocytogenes.</a> Journal of Bacteriology. 179, 1533-1540 (1997).</li><li>Rajabian, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+bacterial+virulence+factor+InlC+perturbs+apical+cell+junctions+and+promotes+cell-to-cell+spread+of+Listeria.">The bacterial virulence factor InlC perturbs apical cell junctions and promotes cell-to-cell spread of Listeria.</a> Nature Cell Biology. 11, 1212-1218 (2009).</li><li>Gouin, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Listeria+monocytogenes+InlC+protein+interferes+with+innate+immune+responses+by+targeting+the+I&#954;B+kinase+subinit+IKK&#945;.">The Listeria monocytogenes InlC protein interferes with innate immune responses by targeting the I&#954;B kinase subinit IKK&#945;.</a> Proceedings of the National Academy of Sciences USA. 107, 17333-17338 (2010).</li><li>Pizarro-Cerd&#225;, J., Lecuit, M., Cossart, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+and+analysing+invasion+of+mammalian+cells+by+bacterial+pathogens:+the+Listeria+monocytogenes+system.">Measuring and analysing invasion of mammalian cells by bacterial pathogens: the Listeria monocytogenes system.</a> Methods in Molecular Microbiology. 31, 161-177 (2002).</li><li>Snijder, B., Sacher, R., R&#228;m&#246;, P., Damm, E. M., Liberali, P., Pelkmans, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Population+context+determines+cell-to-cell+variability+in+endocytosis+and+virus+infection.">Population context determines cell-to-cell variability in endocytosis and virus infection.</a> Nature. 461, 520-523 (2009).</li></ol>

Several parameters are critical for the success of our InlC-detection protocol, including the use of healthy cell lines displaying a sufficiently large cytoplasm to allow an unambiguous detection of the InlC signal. In the assay we present in this article we propose the use of HeLa CCL2 cells, which are particularly well suited for our assay due to the extension of their cytosolic space; other HeLa clones such as HeLa Kyoto cells display a smaller cytoplasm but can be used with our infection protocol (HeLa Kyoto cells ar...

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

The Gram positive bacterium Listeria monocytogenes is a food-borne pathogen that invades host cells, disrupts its internalization vacuole and replicates in the cytoplasm of host cells1. L. monocytogenes ease of manipulation in the laboratory context (rapid growth, low toxicity for healthy individuals) associated with the persistence of bacterial virulence traits observed in cellular and animal models (hemolytic activity, leukocytosis) allowed its initial use in the 1960s as a major model for the study of intracellular parasitism and for the establishment of the theoretical foundations of cellular immunity against infection2. In the late 1980s and early 1990s, the dissection of the bacterial intracellular cycle3 as well as the molecular characterization of the most important bacterial virulence factors4-7 favored the use of L. monocytogenes as a key molecular tool for the manipulation and study of host cell functions. The presence of avirulent (L. innocua) and virulent (L. monocytogenes) species in the Listeria genus paved the way for comparative genomic studies8 that, together with the recent establishment of the complete L. monocytogenes transcriptome9, have increased our understanding of the evolution of L. monocytogenes as a human pathogen and as a model system for infection studies10.
L. monocytogenes induces its internalization into host cells upon interaction of the bacterial surface proteins InlA and InlB with their host cell receptors E-cadherin and Met, respectively11-12. Initial candidate-based studies led to the identification of the &#945;/&#946; catenins-actin link as a significant component of the InlA-invasion pathway13 and of the phosphoinositide 3-kinase (PI 3-K) as a critical effector of the InlB-dependent invasion cascade14-15. Proteomic and functional-based assays subsequently allowed the identification of novel cytoskeletal elements16 and lipid second messengers17 required for host cell invasion. Transcriptional studies18 and mass spectrometry-based quantitative proteomics19 have recently shed new light concerning the activation of host signaling cascades and the repression of immune responses during L. monocytogenes infection. Systems biology approaches based on the inactivation of large sets of genes (kinomes, complete genomes) by small interfering RNA (siRNA) silencing have recently opened new avenues for the analysis of global host signaling cascades in the context of specific cellular functions, including phagocytosis and pathogen internalization20. Genome-wide siRNA screens have been previously performed to investigate cellular cascades required for infection of L. monocytogenes in phagocytic Drosophila S2 cells21-22, but this type of analysis has not been performed in non-phagocytic cells, which represent critical targets for infection in vivo.
We have optimized a protocol for the microscopical detection of late stages of infection by L. monocytogenes that is suited for high-throughput siRNA studies of bacterial entry within epithelial cells. Our assay takes advantage of a highly invasive L. monocytogenes strain that presents a point mutation in PrfA, the major transcriptional regulator of L. monocytogenes virulence factors6: this mutation (named PrfA*) renders PrfA constitutively active23 and leads to an increased expression of the invasion proteins InlA and InlB, therefore favoring bacterial entry in otherwise poorly infected non-phagocytic cells. Our readout for infection is based on the detection of the cytosolic accumulation of the secreted bacterial protein InlC: this molecule is a pleiotropic effector that is expressed preferentially by intra-cytoplasmic L. monocytogenes9 and which participates not only in the bacterial cell-to-cell spread24 but which also modulates host immune responses25. The fluorescent labeling of InlC secretion by intracellular bacteria not only allows to clearly distinguish infected from non-infected cells, but also represents an end-point readout that can be used to subsequently dissect infection in its different steps: entry, vacuolar escape, cytosolic bacterial proliferation and cell-to-cell spread. This microscopy-based protocol can be coupled to siRNA screens therefore to study cellular pathways involved in the infection of host cells by L. 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

Bacterial intracellular pathogens can be conceived as molecular tools to dissect cellular signaling cascades due to their capacity to exquisitely manipulate and subvert cell functions which are required for the infection of host target tissues. Among these bacterial pathogens, Listeria monocytogenes is a Gram positive microorganism that has been used as a paradigm for intracellular parasitism in the characterization of cellular immune responses, and which has played instrumental roles in the discovery of molecular pathways controlling cytoskeletal and membrane trafficking dynamics. In this article, we describe a robust microscopical assay for the detection of late cellular infection stages of L. monocytogenes based on the fluorescent labeling of InlC, a secreted bacterial protein which accumulates in the cytoplasm of infected cells; this assay can be coupled to automated high-throughput small interfering RNA screens in order to characterize cellular signaling pathways involved in the up- or down-regulation of infection.

Fluorescent labeling of cytoplasmic InlC provides a robust readout for cell infection by L. monocytogenes, as illustrated in Figure 1: the central cell in the micrograph is highly infected by the strain P14.PrfA*23 as it can be observed in the phase contrast image (arrowheads, Figure 1A) and it is confirmed by the DAPI signal where individual bacteria can be clearly distinguished (Figure 1B). The InlC staining (superposed to the DAPI staining in Figur...

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 is a Gram positive bacterial pathogen frequently used as a major model for the study of intracellular parasitism. Imaging late L. monocytogenes infection stages within the context of small-interfering RNA screens allows for the global study of cellular pathways required for bacterial infection of target host cells.

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

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

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

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 ...

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

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 ...

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

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 ...

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

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 ...

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

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 ...

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

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 ...

RNA Purification from Intracellularly Grown Listeria monocytogenes in Macrophage Cells

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. ...

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 ...