Name: merkel cell polyomavirus infection and detection
Uploaded: 2019-02-07T13:00:00
Description: Watch this Scientific Journal Video about Merkel Cell Polyomavirus Infection and Detection at JoVE.com

Författarna vill tacka Dr Meenhard Herlyn (Wistar Institute) och Dr. M. Celeste Simon (University of Pennsylvania) för att tillhandahålla reagens och teknisk support. Vi tackar också ledamöterna i våra laboratorier för bra diskussion. Detta arbete stöds av National Institutes of Health (NIH) bidragen (R01CA187718, R01CA148768 och R01CA142723), NCI Cancer Center stöd beviljande (NCI P30 CA016520) och Penn CFAR award (P30 AI 045008).

Human neonatal förhudarna erhölls från Penn Skin Disease Research Center. Vuxen mänskliga fibroblaster erhölls från kasserade normal hud efter operation. Alla protokoll godkändes av University of Pennsylvania institutionella Review Board.
1. isolering av mänskliga dermal fibroblaster
<ol><li>Använda ett par sax för att trimma bort fett och subkutan vävnad från human neonatal Förhud och skära huden provet i halvor eller fjärdedelar.</li>
	<li>Inkubera vävnaden i 5 mL 10 mg/mL ...

<ol>
	<li>Gjoerup, O., Chang, Y., Vande Woude, G., Klein, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Advances in Cancer Research. 106, 1-51 (2010).</li><li>Feng, H., Shuda, M., Chang, Y., Moore, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clonal+integration+of+a+polyomavirus+in+human+Merkel+cell+carcinoma.">Clonal integration of a polyomavirus in human Merkel cell carcinoma.</a> Science. 319, 1096-1100 (2008).</li><li>Lemos, B., Nghiem, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Merkel+cell+carcinoma:+more+deaths+but+still+no+pathway+to+blame.">Merkel cell carcinoma: more deaths but still no pathway to blame.</a> Journal of Investigative Dermatology. 127 (9), 2100-2103 (2007).</li><li>Agelli, M., Clegg, L. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epidemiology+of+primary+Merkel+cell+carcinoma+in+the+United+States.">Epidemiology of primary Merkel cell carcinoma in the United States.</a> Journal of the American Academy of Dermatology. 49 (5), 832-841 (2003).</li><li>Liu, W., MacDonald, M., You, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Merkel+cell+polyomavirus+infection+and+Merkel+cell+carcinoma.">Merkel cell polyomavirus infection and Merkel cell carcinoma.</a> Current Opinion in Virology. 20, 20-27 (2016).</li><li>Harrison, C. J., 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=Asymmetric+Assembly+of+Merkel+Cell+Polyomavirus+Large+T-Antigen+Origin+Binding+Domains+at+the+Viral+Origin.">Asymmetric Assembly of Merkel Cell Polyomavirus Large T-Antigen Origin Binding Domains at the Viral Origin.</a> Journal of Molecular Biology. 409 (4), 529-542 (2011).</li><li>Kwun, H. J., 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+Minimum+Replication+Origin+of+Merkel+Cell+Polyomavirus+Has+a+Unique+Large+T-Antigen+Loading+Architecture+and+Requires+Small+T-Antigen+Expression+for+Optimal+Replication.">The Minimum Replication Origin of Merkel Cell Polyomavirus Has a Unique Large T-Antigen Loading Architecture and Requires Small T-Antigen Expression for Optimal Replication.</a> Journal of Virology. 83 (23), 12118-12128 (2009).</li><li>Carter, J. J., 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=Identification+of+an+overprinting+gene+in+Merkel+cell+polyomavirus+provides+evolutionary+insight+into+the+birth+of+viral+genes.">Identification of an overprinting gene in Merkel cell polyomavirus provides evolutionary insight into the birth of viral genes.</a> Proceedings of the National Academy of Sciences of the United States of America. 110 (31), 12744-12749 (2013).</li><li>Seo, G. J., Chen, C. J., Sullivan, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Merkel+cell+polyomavirus+encodes+a+microRNA+with+the+ability+to+autoregulate+viral+gene+expression.">Merkel cell polyomavirus encodes a microRNA with the ability to autoregulate viral gene expression.</a> Virology. 383 (2), 183-187 (2009).</li><li>Theiss, J. M., 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+Comprehensive+Analysis+of+Replicating+Merkel+Cell+Polyomavirus+Genomes+Delineates+the+Viral+Transcription+Program+and+Suggests+a+Role+for+mcv-miR-M1+in+Episomal+Persistence.">A Comprehensive Analysis of Replicating Merkel Cell Polyomavirus Genomes Delineates the Viral Transcription Program and Suggests a Role for mcv-miR-M1 in Episomal Persistence.</a> PLOS Pathogens. 11 (7), 1004974 (2015).</li><li>Schowalter, R. M., Pastrana, D. V., Buck, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glycosaminoglycans+and+sialylated+glycans+sequentially+facilitate+Merkel+cell+polyomavirus+infectious+entry.">Glycosaminoglycans and sialylated glycans sequentially facilitate Merkel cell polyomavirus infectious entry.</a> PLOS Pathogens. 7 (7), 1002161 (2011).</li><li>Schowalter, R. M., Reinhold, W. C., Buck, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Entry+Tropism+of+BK+and+Merkel+Cell+Polyomaviruses+in+Cell+Culture.">Entry Tropism of BK and Merkel Cell Polyomaviruses in Cell Culture.</a> PLoS One. 7 (7), 42181 (2012).</li><li>Schowalter, R. M., Buck, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Merkel+cell+polyomavirus+minor+capsid+protein.">The Merkel cell polyomavirus minor capsid protein.</a> PLOS Pathogens. 9 (8), 1003558 (2013).</li><li>Houben, R., Schrama, D., Becker, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+pathogenesis+of+Merkel+cell+carcinoma.">Molecular pathogenesis of Merkel cell carcinoma.</a> Experimental Dermatology. 18 (3), 193-198 (2009).</li><li>Chang, Y., Moore, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Merkel+cell+carcinoma:+a+virus-induced+human+cancer.">Merkel cell carcinoma: a virus-induced human cancer.</a> Annual Review of Pathology. 7, 123-144 (2012).</li><li>Hodgson, N. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Merkel+cell+carcinoma:+Changing+incidence+trends.">Merkel cell carcinoma: Changing incidence trends.</a> Journal of Surgical Oncology. 89 (1), 1-4 (2005).</li><li>Tolstov, Y. L., 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=Human+Merkel+cell+polyomavirus+infection+II.+MCV+is+a+common+human+infection+that+can+be+detected+by+conformational+capsid+epitope+immunoassays.">Human Merkel cell polyomavirus infection II. MCV is a common human infection that can be detected by conformational capsid epitope immunoassays.</a> International Journal of Cancer. 125 (6), 1250-1256 (2009).</li><li>Schowalter, R. M., Pastrana, D. V., Pumphrey, K. A., Moyer, A. L., Buck, C. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Merkel+cell+polyomavirus+and+two+previously+unknown+polyomaviruses+are+chronically+shed+from+human+skin.">Merkel cell polyomavirus and two previously unknown polyomaviruses are chronically shed from human skin.</a> Cell Host &amp; Microbe. 7 (6), 509-515 (2010).</li><li>Foulongne, V., 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=Human+Skin+Microbiota:+High+Diversity+of+DNA+Viruses+Identified+on+the+Human+Skin+by+High+Throughput+Sequencing.">Human Skin Microbiota: High Diversity of DNA Viruses Identified on the Human Skin by High Throughput Sequencing.</a> PLoS One. 7 (6), 38499 (2012).</li><li>Hopcraft, S. E., Damania, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumour+viruses+and+innate+immunity.">Tumour viruses and innate immunity.</a> Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 372 (1732), (2017).</li><li>Feng, H., 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=Cellular+and+viral+factors+regulating+Merkel+cell+polyomavirus+replication.">Cellular and viral factors regulating Merkel cell polyomavirus replication.</a> PLoS One. 6 (7), 22468 (2011).</li><li>Neumann, F., 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=Gene+Expression+and+Particle+Production+by+a+Consensus+Merkel+Cell+Polyomavirus+(MCPyV)+Genome.">Gene Expression and Particle Production by a Consensus Merkel Cell Polyomavirus (MCPyV) Genome.</a> PLoS One. 6 (12), 29112 (2011).</li><li>Tsang, S. H., Wang, X., Li, J., Buck, C. B., You, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Host+DNA+damage+response+factors+localize+to+merkel+cell+polyomavirus+DNA+replication+sites+to+support+efficient+viral+DNA+replication.">Host DNA damage response factors localize to merkel cell polyomavirus DNA replication sites to support efficient viral DNA replication.</a> Journal of Virology. 88 (6), 3285-3297 (2014).</li><li>Liu, W., 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=Identifying+the+Target+Cells+and+Mechanisms+of+Merkel+Cell+Polyomavirus+Infection.">Identifying the Target Cells and Mechanisms of Merkel Cell Polyomavirus Infection.</a> Cell Host &amp; Microbe. 19 (6), 775-787 (2016).</li><li>Liu, W., Krump, N. A., MacDonald, M., You, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Merkel+Cell+Polyomavirus+Infection+of+Animal+Dermal+Fibroblasts.">Merkel Cell Polyomavirus Infection of Animal Dermal Fibroblasts.</a> Journal of Virology. 92 (4), (2018).</li><li>Liu, W., 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=BRD4+regulates+Nanog+expression+in+mouse+embryonic+stem+cells+and+preimplantation+embryos.">BRD4 regulates Nanog expression in mouse embryonic stem cells and preimplantation embryos.</a> Cell Death Differ. 21 (12), 1950-1960 (2014).</li><li>Choi, H. M., Beck, V. A., Pierce, N. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Next-generation+in+situ+hybridization+chain+reaction:+higher+gain,+lower+cost,+greater+durability.">Next-generation in situ hybridization chain reaction: higher gain, lower cost, greater durability.</a> ACS Nano. 8 (5), 4284-4294 (2014).</li><li>Buck, C. B., Pastrana, D. V., Lowy, D. R., Schiller, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+intracellular+assembly+of+papillomaviral+vectors.">Efficient intracellular assembly of papillomaviral vectors.</a> Journal of Virology. 78 (2), 751-757 (2004).</li><li>. ccr.cancer.gov Available from: <a target="_blank" href="https://home.ccr.cancer.gov/lco/support.htm">https://home.ccr.cancer.gov/lco/support.htm</a> (2018)</li><li>. ccr.cancer.gov Available from: <a target="_blank" href="https://home.ccr.cancer.gov/lco/BuckLabAntibodies.htm">https://home.ccr.cancer.gov/lco/BuckLabAntibodies.htm</a> (2018)</li><li>. ccr.cancer.gov Available from: <a target="_blank" href="https://home.ccr.cancer.gov/lco/NativeMCVproduction.htm">https://home.ccr.cancer.gov/lco/NativeMCVproduction.htm</a> (2018)</li></ol>

De metoder som beskrivs ovan, inklusive isolering av dermal fibroblaster från mänsklig hudvävnad, beredning av rekombinant MCPyV virioner, infektion i odlade celler, Immunofluorescerande färgning och en känslig fisk metod anpassad från HCR-teknik, som bör göra det möjligt för forskare att analysera MCPyV infektion27. En av de viktigaste stegen till att uppnå MCPyV infektion in vitro-är produktionen av hög-titer virion preparat. Använder protokollet för beredning av rekombinant MCPyV...

Merkel cell polyomavirus (MCPyV) är en liten, dubbelsträngat DNA-virus som har associerats med en sällsynt, men aggressiv hudcancer, Merkel cell carcinoma (MCC)1,2. Dödligheten bland MCC, omkring 33%, överträffar av melanom3,4. MCPyV har en cirkulär genomet ~ 5 kb1,5 genomskärs av en icke-kodande regulatoriska region (NCRR) in i tidig och sen kodande regioner1. NCRR innehåller viral ursprung replikering (Ori) och dubbelriktad initiativtagare för viral transkription6,7. Tidiga regionen kodar tumör antigen proteiner som kallas stora T (LT), liten T (sT), 57kT, alternativa LT ORF (ALTO), samt en autoregulatory miRNA1,8,9,10. Sena regionen kodar den kapsid proteiner VP1 och VP211,12,13. LT och sT är de bäst studerade MCPyV proteinerna och har visat sig stödja den virala DNA-replikation och MCPyV-inducerad tumourigenesis5. Klonal integrering av MCPyV DNA i värd genomet, vilket har observerats i upp till 80% av MCCs, är sannolikt en kausal faktor för virus-positiv tumör utveckling14,15.
Incidensen av MCC har tredubblats under de senaste tjugo år16. Asymtomatisk MCPyV infektion är också utbredd i befolkningen17,18,19. Med det ökande antalet MCC diagnoser och den höga prevalensen av MCPyV infektion finns det ett behov att förbättra vår förståelse av viruset och dess onkogen potential. Många aspekter av MCPyV biologi och onkogena mekanismer är dock dåligt förstådd20. Detta beror till stor del MCPyV replikerar dåligt i etablerade cell linjer11,12,21,22,23 och, tills nyligen, hudceller kan stödja MCPyV infektionen hade inte upptäckt22. Mekanistiska studier att fullt ut undersöka MCPyV och dess samspel med värdceller har hämmats av brist på cellodlingssystem för att sprida virus5.
Vi upptäckte att primära mänskliga dermal fibroblaster (HDFs) isolerade från neonatal mänskliga förhud stöd robust MCPyV infektion både in vitro- och ex vivo24. Från denna studie etablerade vi den första cell kultur infektion modellen för MCPyV24. Bygga på detta modellsystem, visade vi att induktion av matrix metalloproteinas (MMP) gener av den WNT/β-catenin signalering utbildningsavsnitt och andra tillväxtfaktorer stimulerar MCPyV infektion. Vi hittade dessutom att FDA-godkända MEK antagonist trametinib effektivt hämmar MCPyV infektion5,25. Från dessa studier har etablerat vi också en uppsättning protokoll för att isolera mänskliga dermal fibroblaster24,25, förbereda MCPyV virioner11,12, utför MCPyV infektion på mänskliga dermal fibroblaster 24 , 25 och upptäcka MCPyV proteiner av om färgning26. Dessutom anpassat vi jordbaserad DNA hybridisering kedjereaktion (HCR) teknik27 för att utveckla en känslig fisk teknik (HCR-DNA fisk) för att upptäcka MCPyV DNA i infekterade mänskliga hudceller. Dessa nya metoder kommer att vara användbart för att studera den smittsamma cykeln av MCPyV as well as den cellulära svaren på MCPyV infektion. De naturliga reservoaren värdceller som upprätthåller MCPyV infektion och de celler som ger upphov till MCC tumörer förblir okänd. De tekniker som vi beskriver i detta manuskript skulle kunna tillämpas för att undersöka olika typer av mänskliga celler att identifiera både reservoar cellerna och ursprung av MCC tumörer. Våra etablerade metoder, såsom HCR-DNA fisk, kunde också vara anställd i upptäckt av andra DNA tumörvirus och karakterisering av värd-cell interaktioner.

<table border="0" cellpadding="0" cellspacing="0" style="width:837px;" width="838">
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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Fetal calf serum</td>
			<td style="width:185px;">HyClone</td>
			<td style="width:119px;">SH30071.03</td>
			<td style="width:195px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">MEM Non-Essential Amino Acids Solution, 100X</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td>11140050</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">GLUTAMAX I, 100X</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td>35050061</td>
			<td>L-Glutamine</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">DPBS, no calcium, no magnesium</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td>14190136</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">0.05% Trypsin-EDTA</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td>25300-054</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">DMEM/F12 medium</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td>11330-032</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Recombinant Human EGF Protein, CF</td>
			<td style="width:185px;">R&#38;D systems</td>
			<td>236-EG-200</td>
			<td>Store at -80 degree celsius</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">CHIR99021</td>
			<td style="width:185px;">Cayman Chemical</td>
			<td>13122</td>
			<td>Store at -80 degree celsius</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">CHIR99021</td>
			<td style="width:185px;">Sigma</td>
			<td>SML1046</td>
			<td>Store at -80 degree celsius</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Collagenase type IV</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td>17104019</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Dispase II</td>
			<td style="width:185px;">Roche</td>
			<td>4942078001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Antibiotic-Antimycotic</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td>15240-062</td>
			<td>Protect from light</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">DMEM medium</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td>11965084</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Alexa Fluor 594 goat anti-mouse IgG</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td>A11032</td>
			<td>Protect from light</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Alexa Fluor 488 goat anti-rabbit IgG</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td>A11034</td>
			<td>Protect from light</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">OptiPrep Density Gradient Medium</td>
			<td style="width:185px;">Sigma</td>
			<td>D1556</td>
			<td>Protect from light</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Paraformaldehyde</td>
			<td style="width:185px;">Sigma</td>
			<td>P6148</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">anti-MCPyV LT (CM2B4)</td>
			<td style="width:185px;">Santa Cruz</td>
			<td>sc-136172</td>
			<td>Lot # B2717</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">MCV VP1 rabbit</td>
			<td style="width:185px;"></td>
			<td>Rabbit polyclonal serum #10965</td>
			<td>https://home.ccr.cancer.gov/lco/BuckLabAntibodies.htm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Hygromycin</td>
			<td style="width:185px;">Roche</td>
			<td>10843555001</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:339px;">Basic Fibroblast Growth Factors (bFGF), Human Recombinant</td>
			<td style="width:185px;">Corning</td>
			<td>354060</td>
			<td>Store at -80 degree celsius</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Benzonase Nuclease</td>
			<td style="width:185px;">Sigma</td>
			<td>E8263</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Plasmid-Safe ATP-Dependent DNase</td>
			<td style="width:185px;">EPICENTRE</td>
			<td>E3101K</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Probe hybridization buffer</td>
			<td style="width:185px;">Molecular technologies</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:339px;">Probe wash buffer</td>
			<td style="width:185px;">Molecular technologies</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Amplification buffer</td>
			<td style="width:185px;">Molecular technologies</td>
			<td style="width:119px;"></td>
			<td style="width:195px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Alexa 594-labeled hairpins</td>
			<td style="width:185px;">Molecular technologies</td>
			<td>B4</td>
			<td>Protect from light</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Triton X-100</td>
			<td style="width:185px;">Sigma</td>
			<td style="width:119px;">X100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Quant-iT PicoGreen dsDNA Reagent</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td style="width:119px;">P7581</td>
			<td style="width:195px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">BamHI-HF</td>
			<td style="width:185px;">NEB</td>
			<td style="width:119px;">R3136</td>
			<td style="width:195px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">Buffer PB</td>
			<td style="width:185px;">Qiagen</td>
			<td style="width:119px;">19066</td>
			<td style="width:195px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">blue miniprep spin column</td>
			<td style="width:185px;">Qiagen</td>
			<td style="width:119px;">27104</td>
			<td style="width:195px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">50mL Conical Centrifuge Tubes</td>
			<td style="width:185px;">Corning</td>
			<td style="width:119px;">352070</td>
			<td style="width:195px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:339px;">T4 ligase</td>
			<td style="width:185px;">NEB</td>
			<td style="width:119px;">M0202T</td>
			<td style="width:195px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">MagicMark XP</td>
			<td style="width:185px;">Thermo Fisher Scientific</td>
			<td style="width:119px;">LC5602</td>
			<td></td>
		</tr>
	</tbody>
</table>

merkel cell polyomavirus infection and detection

Merkel cell polyomavirus (MCPyV) infektion kan leda till Merkelcellskarcinom (MCC), en mycket aggressiv form av hudcancer. Mekanistiska studier att fullt ut undersöka MCPyV molekylärbiologi och onkogena mekanismer har hämmats av brist på tillräcklig cell kultur modeller. Här, beskriver vi en uppsättning protokoll för att utföra och att upptäcka MCPyV infektion i primära mänskliga hudceller. Protokollen beskriva isolering av mänskliga dermal fibroblaster, beredning av rekombinant MCPyV virioner och upptäckt av virusinfektion av både Immunofluorescerande (om) färgning och jordbaserad DNA-hybridisering kedjereaktion (HCR), som är en mycket känslig fluorescens i situ hybridisering (FISH) tillvägagångssätt. Protokoll som häri kan anpassas av intresserade forskare att identifiera andra celltyper eller cellinjer som stöder MCPyV infektion. Metoden beskrivs fisk kan också anpassas för att upptäcka låga nivåer av viral DNAs närvarande i den infektera mänskliga huden.

Protokollet beskrivs i detta manuskript tillåtna isolering av en nästan homogen befolkning på HDFs (figur 1). Som framgår av Immunofluorescerande färgning, färgas nästan 100% av den mänskliga dermal celler isolerade med de villkor som beskrivs i detta protokoll var positivt för dermal fibroblast markörer, vimentin och kollagen jag24, men negativ för mänskliga förhud keratinocyter markör K14 (figur 1</...

Watch this Scientific Journal Video about Merkel Cell Polyomavirus Infection and Detection at JoVE.com

Merkel Cell Polyomavirus Infection and Detection

Här presenterar vi ett protokoll för att infektera primära mänskliga dermal fibroblast med MCPyV. Protokollet omfattar isolering av dermal fibroblaster, utarbetande av MCPyV virioner, virusinfektion, immunofluorescens färgning och fluorescens in situ hybridisering. Detta protokoll kan förlängas karaktärisera MCPyV-host interaktioner och upptäcka andra celltyper som infectable av MCPyV.

Merkel Cell Polyomavirus infektion och upptäckt

Merkel cell polyomavirus (MCPyV) infection can lead to Merkel cell carcinoma (MCC), a highly aggressive form of skin cancer. Mechanistic studies to fully ...

Vi presenterade den första cellen kultur modell för Merkel Cell Polyomavirus infektion. Protokollet omfattar isolering av de dermal fibroblaster, beredning av MCPyV virusinfektion, immunofluorescerande färgning och fluorescerande in situ hybridisering. Detta protokoll gör det möjligt att studera MCPyV smittsam cykel och interaktioner med värdceller samtidigt som man undviker artefakter som är associerade med över-uttryck av virala gener.Till att börja med använd en sax för att trimma fett och subkutan vävnad bort av den mänskliga neonatal förhuden. Skär hudprovet i halvor eller kvartsparter. Placera vävnaden i 5 milliliter av 10 milligram per milliliter dis-based II NPBS, kompletterat med antibiotika-antimycotic.Inkubera vid 4 grader Celsius över natten. Nästa dag, använd microdissection-forceper för att noggrant separera epidermis från de dermala lagren i en 10 centimeters skål. Överför den resulterande dermal vävnaden till en 15 milliliter koniska röret som innehåller 5 milliliter av 2 milligram per milliliter kollagenas typ IV i FBS-fritt medium kompletteras med antibiotika-anitmycotic.Inkubera provet vid 37 grader Celsius i 5%koldioxid med periodisk skakning i fyra till sex timmar, tills bara några makroskopiska vävnad aggregat kvar. Efter detta, använd en 10 milliliter pipett för att pipettera provlösningen upp och ner kraftigt 10 gånger, släppa enstaka celler från dermis. Centrifugera vid 180 g i fem minuter och kassera supernatanten.Plate de dissociated cellerna i kompletterat DMEM medium. Under sen eftermiddag eller kväll, utsäde 6 miljoner 293TT28 celler i en 10 centimeter skålen innehåller kompletterat DMEM medium. Inkubera vid 37 grader Celsius med 5%koldioxid.Nästa morgon, se till att cellerna är ca 50%konfluent, sedan transfekt cellerna med 66 mikroliter av transfection reagens, 12 mikrogram re-ligated MCPyV isolera R17B DNA, 8,4 mikrogram ST uttryck plasmid pMtB, och 9,6 mikrogram LT uttryck plamids pADL. Inkubera cellerna över natten vid 37 grader Celsius med 5%koldioxid. Följande dag, när de transfekterade cellerna är nästan konfluenta, trypsinize cellerna och överföra dem till en 15 centimeter skål för fortsatt expansion.När den skålen blir nästan konfluent, överföra cellerna i tre nya 15 centimeter rätter. När dessa nya rätter blir nästan konfluenta, skörda cellerna som beskrivs i textprotokollet. Centrifug vid 180 g vid rumstemperatur i fem minuter.Ta sedan bort supernatanten och tillsätt en cellvolym av DPBS magnesium. Tillsätt 25 mikromolar ammoniumsulfat, följt av 0,5%Triton X-100, 0,1%bensoas, och 0,1%av en ATP-beroende DNAse. Blanda väl och inkubera vid 37 grader Celsius över natten.Nästa dag, kyla blandningen på is i 15 minuter. Därefter lägger du till 0,17 volym natriumklorid. Blanda och inkubera på is i ytterligare 15 minuter.Centrifugera vid 12 tusen g vid 4 grader Celsius i 10 minuter. Om supernatanten inte är klar, invänd försiktigt röret och upprepa centrifugeringen. Efter detta överför du supernatanten till ett nytt rör.Resuspend pelleten i 1 volym av DPBS kompletteras med 0,8 mol av natriumklorid. Centrifug vid 12 tusen g vid fyra grader Celsius i 10 minuter. Om supernatanten inte är klar, invänd försiktigt röret och upprepa centrifugeringen.Kombinera de två supernatanterna och centrifugen igen vid 12 tusen g vid fyra grader Celsius i 10 minuter. Använd sedan en pipett för att deponera gradienter av iodixanol i tunnväggiga fem milliliter polyallomerrör som beskrivs i textprotokollet. Ladda 3 milliliter av den klarspretta virusinnehållande supernatanten ovanpå den förberedda iodixanolgradienten.Centrifugera med en SW 55 Ti rotor på 234 tusen g och vid 16 grader Celsius i 3,5 timmar, se till att ställa in accelerationen och inbromsningen till långsam. Efter att ultracentrifugeringen är klar, samla 12 fraktioner i silikoniserade rör. Efter att ha underhållit och lossat cellerna, vid 10 milliliter av kompletterat DMEM och F12 medium till skålen.Överför celllösningen till ett 15 milliliterrör. Centrifug vid 180 g i två minuter. Kassera supernatant och åter upphäva cellerna i kompletterade DMEM och F12 medium vid en celltäthet mellan 20 tusen och 40 tusen celler per milliliter.Sedan, utsäde 200 eller 400 mikroliter av cellen suspension kompletteras med 1 milligram per milliliter av kollagenas typ IV i varje brunn av en 24 eller 96 väl platta, respektive. Ta bort MCPyV viron lager från minus 80 grader Celsius frys och placera på is att tina. Lägg till 1 miljard virala genomekvivalenter av MCPyV virions per en mikroliter av iodixanol för varje 2500 till 5000 celler som ska infekteras.Knacka på sidan av plattan försiktigt, och inkubera i 37 grader Celsius med 5%koldioxid. Först, fixa cellerna på locket glider med 4%PFA i PBS i 10 minuter, sedan tvätta locket glider två gånger med PBS och behandla dem med 70%etanol vid fyra grader Celsius över natten för att permeabilisera cellerna. Nästa dag, byt ut etanol med sondhydratiseringsbuffert och inkubera vid rumstemperatur i 60 minuter för att förhybridisera proverna.30 minuter före slutet av inkuberingen före hybridisering späder man ut sonderna i sondhybritiseringslösning vid en spädning 1:500 och inkubera vid 45 grader Celsius. När inkubationerna är klara, pipettera cirka 10 mikroliter av den utspädda sondblandningen på ett mikroskopsglas för varje täcksli. Placera varje täcka glida cellen sidan ner på dess respektive droppe av hybridisering mix.Med hjälp av en liberal mängd gummicement, försegla kanterna och baksidan av varje omslag glida till dess bild. Ställ in glidningen på den platta sidan av ett värmeblock och värm dem till 94 grader Celsius i tre minuter. Efter detta överför du bilden till en befuktad kammare och ruvar dem i 45 grader Celsius över natten.Nästa dag, använd forceps för att försiktigt skala bort gummicement. Placera locket glider cellsidan upp i brunnarna på en 24 brunnsplatta och tvätta dem med sondtvättbuffert tre gånger i rumstemperatur. Tillsätt 200 mikroliter av förstärkningsbuffert till varje brunn som innehåller en täcksli och inkubera i rumstemperatur i 30 till 60 minuter.Under tiden, anneal var och en av de två märkta oligonukleotide hårnålar erkänner sonderna i separata PCR rör genom att värma dem till 94 grader Celsius i 90 sekunder, och sedan kyla dem till rumstemperatur i 30 minuter. Blanda ihop hårnålarna i förstärkningsbuffert vid en spädning av 1:50. Därefter stretch paraffin film över den öppna ytan av en 12 väl tallrik lock för att göra en yta för förstärkning reaktion.Pipett 50-100 mikroliterdroppar av hårnålsblandningen på paraffinfilmen för varje täcksli. Använd tövröj, ta försiktigt bort varje täckslir från förförstärkningslösningen och vidrör kanten till en porös engångstorka för att torka. Placera varje torkad täckslircellssida ner på en amplifieringsdropp.Överför tallrikslocket till en befuktad kammare och inkubera över natten i rumstemperatur och i mörker. Nästa dag, tillbaka locket glider till brunnarna i 24 brunnsplattan. Tillsätt 5X SSCT innehållande DAPI vid en koncentration på 0,5 mikrogram per milliliter till varje brunn och inkubera vid rumstemperatur i en timme.Efter detta tvättar du proverna två gånger med 5X SSCT i rumstemperatur. Montera det tvättade locket glider på mikroskopglas, och använd ett inverterat fluorescensmikroskop för att analysera cellerna och avbilda proverna. I denna studie, en nästan-homogena population av mänskliga dermal fibroblaster är isolerade.Immunofluorescent färgning avslöjar att nästan 100%av de isolerade mänskliga dermal celler är positivt färgas för dermal fibroblast markörer, vimentin och kollagen, men negativt för mänskliga förhud keratinocyte markör K14. MCPyV virions genereras sedan och efter visualisera bandet av MCPyV virions koncentrerade i kärnan av lutningen, 500 microliter fraktioner samlas in och MCPyV qPCR utförs för att identifiera toppfraktioner. Immunofluorescerande färgade bilder av HDFs infekterade med MCPyV visas här, där celler som är LT positiva, VP1 positiva, eller både LT och VP1 positiva anses vara positiva för MCPyV infektion.Över 30%av celler är LT positiva, och mer än 10%är VP1 positiva. MCPyV genomen som replikeras i de infekterade cellerna upptäcks med hjälp av både HCR-DNA FISH och Immunofluorescent-HCR-DNA FISH. Medan HCR-DNA FISH avslöjar lokaliseringen av MCPyV DNA som finns i replikeringsfabriken, immunofluorescent-HCR-DNA FISH metoder tillåta samtidig upptäckt av både MCPyV DNA och LT protein samlokalisering vid replikeringscentra.För att uppnå bästa virusinfektion effektivitet, det är mycket viktigt att MCPyV är koncentrerad till minst 2 x 10 till 8: e virusgenomet per microliter eftersom iodoxanol är giftigt för cellerna. Efter MCPyV infektion av de dermal fibroblaster, många molekylära biologiska analyser kan utföras, inklusive immunofluorescens, immuno-blockering, immunopositivication och qPCR-baserade analys. Infektionssystemet som vi har beskrivit gör det möjligt för forskare att studera stadier av MCPyV-infektion som nukleär handel och virusförpackningar.MCPyV är ett BSL-2-virus, men lite är känt om dess potential för patologi i de mängder som uppnås i ett laboratorium inställning. Därför bör forskare vidta försiktighetsåtgärder för att undvika exponering för viruset.

merkel-cell-polyomavirus-infection-and-detection

Research

JoVE Journal

Immunology and Infection

Combination of Adhesive-tape-based Sampling and Fluorescence in situ Hybridization for Rapid Detection of Salmonella on Fresh Produce

This protocol describes a simple approach for adhesive-tape-based sampling of tomato and other fresh produce surfaces, followed by on-tape fluorescence in situ hybridization (FISH) for rapid culture-independent detection of Salmonella spp. Cell-charged tapes can also be placed face-down on selective agar for solid-phase enrichment prior to detection. Alternatively, low-volume liquid enrichments (liquid surface miniculture) can be performed on the surface of the tape in non-selective broth, followed by FISH and analysis via flow cytometry. To begin, sterile adhesive tape is brought into contact with fresh produce, gentle pressure is applied, and the tape is removed, physically extracting microbes present on these surfaces. Tapes are mounted sticky-side up onto glass microscope slides and the sampled cells are fixed with 10% formalin (30 min) and dehydrated using a graded ethanol series (50, 80, and 95%; 3 min each concentration). Next, cell-charged tapes are spotted with buffer containing a Salmonella-targeted DNA probe cocktail and hybridized for 15 - 30 min at 55&deg;C, followed by a brief rinse in a washing buffer to remove unbound probe. Adherent, FISH-labeled cells are then counterstained with the DNA dye 4',6-diamidino-2-phenylindole (DAPI) and results are viewed using fluorescence microscopy. For solid-phase enrichment, cell-charged tapes are placed face-down on a suitable selective agar surface and incubated to allow in situ growth of Salmonella microcolonies, followed by FISH and microscopy as described above. For liquid surface miniculture, cell-charged tapes are placed sticky side up and a silicone perfusion chamber is applied so that the tape and microscope slide form the bottom of a water-tight chamber into which a small volume (&le; 500 &mu;L) of Trypticase Soy Broth (TSB) is introduced. The inlet ports are sealed and the chambers are incubated at 35 - 37&deg;C, allowing growth-based amplification of tape-extracted microbes. Following incubation, inlet ports are unsealed, cells are detached and mixed with vigorous back and forth pipetting, harvested via centrifugation and fixed in 10% neutral buffered formalin. Finally, samples are hybridized and examined via flow cytometry to reveal the presence of Salmonella spp. As described here, our "tape-FISH" approach can provide simple and rapid sampling and detection of Salmonella on tomato surfaces. We have also used this approach for sampling other types of fresh produce, including spinach and jalape&ntilde;o peppers.

Combination of Adhesive-tape-based Sampling and Fluorescence in situ Hybridization for Rapid Detection of Salmonella on Fresh Produce

This protocol describes a simple adhesive-tape-based approach for sampling of tomato and other fresh produce surfaces, followed by rapid whole cell detection of Salmonella using fluorescence in situ hybridization (FISH).

Kombination av självhäftande tejp grundad på provtagning och fluorescens På plats Hybridisering för snabb upptäckt av Salmonella På färskvaror

This protocol describes a simple approach for adhesive-tape-based sampling of tomato and other fresh produce surfaces, followed by on-tape fluorescence in ...

Detection of Infectious Virus from Field-collected Mosquitoes by Vero Cell Culture Assay

Mosquitoes transmit a number of distinct viruses including important human pathogens such as West Nile virus, dengue virus, and chickungunya virus. Many of these viruses have intensified in their endemic ranges and expanded to new territories, necessitating effective surveillance and control programs to respond to these threats. One strategy to monitor virus activity involves collecting large numbers of mosquitoes from endemic sites and testing them for viral infection. In this article, we describe how to handle, process, and screen field-collected mosquitoes for infectious virus by Vero cell culture assay. Mosquitoes are sorted by trap location and species, and grouped into pools containing &le;50 individuals. Pooled specimens are homogenized in buffered saline using a mixer-mill and the aqueous phase is inoculated onto confluent Vero cell cultures (Clone E6). Cell cultures are monitored for cytopathic effect from days 3-7 post-inoculation and any viruses grown in cell culture are identified by the appropriate diagnostic assays. By utilizing this approach, we have isolated 9 different viruses from mosquitoes collected in Connecticut, USA, and among these, 5 are known to cause human disease. Three of these viruses (West Nile virus, Potosi virus, and La Crosse virus) represent new records for North America or the New England region since 1999. The ability to detect a wide diversity of viruses is critical to monitoring both established and newly emerging viruses in the mosquito population.

We describe a method to process and screen field-collected mosquitoes for a diversity of viruses by Vero cell culture assay. By employing this technique, we have detected 9 different viruses from 4 taxonomic families in mosquitoes collected in Connecticut.

Detektion av infektiösa virus från Field-in Myggor av vero-cellodling analys

Mosquitoes transmit a number of distinct viruses including important human pathogens such as West Nile virus, dengue virus, and chickungunya virus. Many ...

Single-cell Analysis of Bacillus subtilis Biofilms Using Fluorescence Microscopy and Flow Cytometry

Biofilm formation is a general attribute to almost all bacteria 1-6. When bacteria form biofilms, cells are encased in extracellular matrix that is mostly constituted by proteins and exopolysaccharides, among other factors 7-10. The microbial community encased within the biofilm often shows the differentiation of distinct subpopulation of specialized cells 11-17. These subpopulations coexist and often show spatial and temporal organization within the biofilm 18-21.
Biofilm formation in the model organism Bacillus subtilis requires the differentiation of distinct subpopulations of specialized cells. Among them, the subpopulation of matrix producers, responsible to produce and secrete the extracellular matrix of the biofilm is essential for biofilm formation 11,19. Hence, differentiation of matrix producers is a hallmark of biofilm formation in B. subtilis.
We have used fluorescent reporters to visualize and quantify the subpopulation of matrix producers in biofilms of B. subtilis 15,19,22-24. Concretely, we have observed that the subpopulation of matrix producers differentiates in response to the presence of self-produced extracellular signal surfactin 25. Interestingly, surfactin is produced by a subpopulation of specialized cells different from the subpopulation of matrix producers 15.
We have detailed in this report the technical approach necessary to visualize and quantify the subpopulation of matrix producers and surfactin producers within the biofilms of B. subtilis. To do this, fluorescent reporters of genes required for matrix production and surfactin production are inserted into the chromosome of B. subtilis. Reporters are expressed only in a subpopulation of specialized cells. Then, the subpopulations can be monitored using fluorescence microscopy and flow cytometry (See Fig 1).
The fact that different subpopulations of specialized cells coexist within multicellular communities of bacteria gives us a different perspective about the regulation of gene expression in prokaryotes. This protocol addresses this phenomenon experimentally and it can be easily adapted to any other working model, to elucidate the molecular mechanisms underlying phenotypic heterogeneity within a microbial community.

Single-cell Analysis of Bacillus subtilis Biofilms Using Fluorescence Microscopy and Flow Cytometry

Microbial biofilms are generally constituted by distinct subpopulations of specialized cells. Single-cell analysis of these subpopulations requires the use of fluorescent reporters. Here we describe a protocol to visualize and monitor several subpopulationswithin B. subtilis biofilms using fluorescence microscopy and flow cytometry.

Encelliga Analys av Bacillus subtilis Biofilmer Använda fluorescensmikroskopi och flödescytometri

Biofilm formation is a general attribute to almost all bacteria 1-6. When bacteria form biofilms, cells are encased in extracellular matrix that is mostly ...

A Visual Assay to Monitor T6SS-mediated Bacterial Competition

Type VI secretion systems (T6SSs) are molecular nanomachines allowing Gram-negative bacteria to transport and inject proteins into a wide variety of target cells1,2. The T6SS is composed of 13 core components and displays structural similarities with the tail-tube of bacteriophages3. The phage uses a tube and a puncturing device to penetrate the cell envelope of target bacteria and inject DNA. It is proposed that the T6SS is an inverted bacteriophage device creating a specific path in the bacterial cell envelope to drive effectors and toxins to the surface. The process could be taken further and the T6SS device could perforate other cells with which the bacterium is in contact, thus injecting the effectors into these targets. The tail tube and puncturing device parts of the T6SS are made with Hcp and VgrG proteins, respectively4,5.
The versatility of the T6SS has been demonstrated through studies using various bacterial pathogens. The Vibrio cholerae T6SS can remodel the cytoskeleton of eukaryotic host cells by injecting an "evolved" VgrG carrying a C-terminal actin cross-linking domain6,7. Another striking example was recently documented using Pseudomonas aeruginosa which is able to target and kill bacteria in a T6SS-dependent manner, therefore promoting the establishment of bacteria in specific microbial niches and competitive environment8,9,10.
In the latter case, three T6SS-secreted proteins, namely Tse1, Tse2 and Tse3 have been identified as the toxins injected in the target bacteria (Figure 1). The donor cell is protected from the deleterious effect of these effectors via an anti-toxin mechanism, mediated by the Tsi1, Tsi2 and Tsi3 immunity proteins8,9,10. This antimicrobial activity can be monitored when T6SS-proficient bacteria are co-cultivated on solid surfaces in competition with other bacterial species or with T6SS-inactive bacteria of the same species8,11,12,13.
The data available emphasized a numerical approach to the bacterial competition assay, including time-consuming CFU counting that depends greatly on antibiotic makers. In the case of antibiotic resistant strains like P. aeruginosa, these methods can be inappropriate. Moreover, with the identification of about 200 different T6SS loci in more than 100 bacterial genomes14, a convenient screening tool is highly desirable. We developed an assay that is easy to use and requires standard laboratory material and reagents. The method offers a rapid and qualitative technique to monitor the T6SS-dependent bactericidal/bacteriostasis activity by using a reporter strain as a prey (in this case Escherichia coli DH5&alpha;) allowing a-complementation of the lacZ gene. Overall, this method is graphic and allows rapid identification of T6SS-related phenotypes on agar plates. This experimental protocol may be adapted to other strains or bacterial species taking into account specific conditions such as growth media, temperature or time of contact.

We describe a qualitative assay to monitor bacterial competition mediated by the Pseudomonas aeruginosa type VI secretion system (T6SS). The assay relies on the survival/killing of Escherichia coli target cells carrying a lacZ-reporter. This technique is adjustable to assess the bactericidal/bacteriostasis activity of T6SS-proficient microorganisms.

En visuell analys för att övervaka T6SS-medierad bakteriell konkurrens

Type VI secretion systems (T6SSs) are molecular  nanomachines allowing Gram-negative bacteria to transport and inject proteins  into a wide variety of ...

Detection of Fluorescent Nanoparticle Interactions with Primary Immune Cell Subpopulations by Flow Cytometry

Engineered nanoparticles are endowed with very promising properties for therapeutic and diagnostic purposes. This work describes a fast and reliable method of analysis by flow cytometry to study nanoparticle interaction with immune cells. Primary immune cells can be easily purified from human or mouse tissues by antibody-mediated magnetic isolation. In the first instance, the different cell populations running in a flow cytometer can be distinguished by the forward-scattered light (FSC), which is proportional to cell size, and the side-scattered light (SSC), related to cell internal complexity. Furthermore, fluorescently labeled antibodies against specific cell surface receptors permit the identification of several subpopulations within the same sample. Often, all these features vary when cells are boosted by external stimuli that change their physiological and morphological state. Here, 50 nm FITC-SiO2 nanoparticles are used as a model to identify the internalization of nanostructured materials in human blood immune cells. The cell fluorescence and side-scattered light increase after incubation with nanoparticles allowed us to define time and concentration dependence of nanoparticle-cell interaction. Moreover, such protocol can be extended to investigate Rhodamine-SiO2 nanoparticle interaction with primary microglia, the central nervous system resident immune cells, isolated from mutant mice that specifically express the Green Fluorescent Protein (GFP) in the monocyte/macrophage lineage. Finally, flow cytometry data related to nanoparticle internalization into the cells have been confirmed by confocal microscopy.

Analysis of nanoparticle interaction with defined subpopulations of immune cells by flow cytometry.

Upptäckt av fluorescerande nanopartiklar Interaktion med Primär Immun cellsubpopulationer med flödescytometri

Engineered nanoparticles are endowed with very promising properties for therapeutic and diagnostic purposes. This work describes a fast and reliable ...

Detection of Trypanosoma brucei Variant Surface Glycoprotein Switching by Magnetic Activated Cell Sorting and Flow Cytometry

Trypanosoma brucei, a protozoan parasite that causes both Human and Animal African Trypanosomiasis (known as sleeping sickness and nagana, respectively) cycles between a tsetse vector and a mammalian host. It evades the mammalian host immune system by periodically switching the dense, variant surface glycoprotein (VSG) that covers its surface. The detection of antigenic variation in Trypanosoma brucei can be both cumbersome and labor intensive. Here, we present a method for quantifying the number of parasites that have 'switched' to express a new VSG in a given population. The parasites are first stained with an antibody against the starting VSG, and then stained with a secondary antibody attached to a magnetic bead. Parasites expressing the starting VSG are then separated from the rest of the population by running the parasites over a column attached to a magnet. Parasites expressing the dominant, starting VSG are retained on the column, while the flow-through contains parasites that express a new VSG as well as some contaminants expressing the starting VSG. This flow-through population is stained again with a fluorescently labeled antibody against the starting VSG to label contaminants, and propidium iodide (PI), which labels dead cells. A known number of absolute counting beads that are visible by flow cytometry are added to the flow-through population. The ratio of beads to number of cells collected can then be used to extrapolate the number of cells in the entire sample. Flow cytometry is used to quantify the population of switchers by counting the number of PI negative cells that do not stain positively for the starting, dominant VSG. The proportion of switchers in the population can then be calculated using the flow cytometry data.

Detection of Trypanosoma brucei Variant Surface Glycoprotein Switching by Magnetic Activated Cell Sorting and Flow Cytometry

African trypanosomes grown in vitro undergo antigenic variation at a low rate, such that populations are made up of parasites expressing a dominant variant surface glycoprotein (VSG) type and a small population of "switched" variants. This protocol describes a fast method for detecting and quantifying these populations.

detektering av<em&gt; Trypanosoma brucei</em&gt; Variant ytglykoprotein Omkoppling av magnetkamera Aktivt cellsortering och flödescytometri

Trypanosoma brucei, a protozoan parasite that causes both Human and Animal African Trypanosomiasis (known as sleeping sickness and nagana, respectively) ...

In Vivo Assay for Detection of Antigen-specific T-cell Cytolytic Function Using a Vaccination Model

Current methodologies for antigen-specific killing are limited to in vitro use or utilized in infectious disease models. However, there is not a protocol specifically intended to measure antigen-specific killing without an infection. This protocol is designed and describes methods to overcome these limitations by allowing for the detection of antigen-specific killing of a target cell by CD8+ T cells in vivo. This is accomplished by merging a vaccination model with a traditional CFSE-labeled target killing assay. This combination allows the researcher to assess the antigen-specific CTL potential directly and quickly as the assay is not dependent upon tumor growth or infection. In addition, the readout is based on flow cytometry and so should be readily accessible to most researchers. The major limitation of the study is identifying the timeline in vivo that is appropriate to the hypothesis being tested. Variations in antigen strength and mutations in the T cells that may result in differential cytolytic function need to be carefully assessed to determine the optimal time for cell harvest and assessment. The appropriate concentration of peptide for vaccination has been optimized for hgp10025-33 and OVA257-264, but further validation would be needed for other peptides that may be more appropriate to a given study. Overall, this protocol allows a quick assessment of killing function in vivo and can be adapted to any given antigen.

In Vivo Assay for Detection of Antigen-specific T-cell Cytolytic Function Using a Vaccination Model

The goal of this protocol is to allow for detection of in vivo antigen-specific killing of a target cell in a murine model.

In Vivo Test för påvisande av Antigen-specifika T-cell cytolytisk funktion använder en Vaccination modell

Current methodologies for antigen-specific killing are limited to in vitro use or utilized in infectious disease models. However, there is not a protocol ...

Ultrasensitive Detection of Biomarkers by Using a Molecular Imprinting Based Capacitive Biosensor

The ability to detect and quantitate biomolecules in complex solutions has always been highly sought-after within natural science; being used for the detection of biomarkers, contaminants, and other molecules of interest. A commonly used technique for this purpose is the Enzyme-linked Immunosorbent Assay (ELISA), where often one antibody is directed towards a specific target molecule, and a second labeled antibody is used for the detection of the primary antibody, allowing for the absolute quantification of the biomolecule under study. However, the usage of antibodies as recognition elements limits the robustness of the method; as does the need of using labeled molecules. To overcome these limitations, molecular imprinting has been implemented, creating artificial recognition sites complementary to the template molecule, and obsoleting the necessity of using antibodies for initial binding. Further, for even higher sensitivity, the secondary labeled antibody can be replaced by biosensors relying on the capacitance for the quantification of the target molecule. In this protocol, we describe a method to rapidly and label-free detect and quantitate low-abundant biomolecules (proteins and viruses) in complex samples, with a sensitivity that is significantly better than commonly used detection systems such as the ELISA. This is all mediated by molecular imprinting in combination with a capacitance biosensor.

Here, we present a protocol for the detection and quantification of low abundant molecules in complex solutions using molecular imprinting in combination with a capacitance biosensor.

Ultrasensitive identifiering av biomarkörer med hjälp av en Molecular Imprinting baserat kapacitiv Biosensor

The ability to detect and quantitate biomolecules in complex solutions has always been highly sought-after within natural science; being used for the ...

Detection of Inflammasome Activation and Pyroptotic Cell Death in Murine Bone Marrow-derived Macrophages

Inflammasomes are innate immune signaling platforms that are required for the successful control of many pathogenic organisms, but also promote inflammatory and autoinflammatory diseases. Inflammasomes are activated by cytosolic pattern recognition receptors, including members of the NOD-like receptor (NLR) family. These receptors oligomerize upon the detection of microbial or damage-associated stimuli. Subsequent recruitment of the adaptor protein ASC forms a microscopically visible inflammasome complex, which activates caspase-1 through proximity-induced auto-activation. Following the activation, caspase-1 cleaves pro-IL-1&#946; and pro-IL-18, leading to the activation and secretion of these pro-inflammatory cytokines. Caspase-1 also mediates the inflammatory form of cell death termed pyroptosis, which features the loss of membrane integrity and cell lysis. Caspase-1 cleaves gasdermin D, releasing the N-terminal fragment which forms plasma membrane pores, leading to osmotic lysis.
In vitro, the activation of caspase-1 can be determined by labeling bone marrow-derived macrophages with the caspase-1 activity probe FAM-YVAD-FMK and by labeling the cells with antibodies against the adaptor protein ASC. This technique allows the identification of inflammasome formation and caspase-1 activation in individual cells using fluorescence microscopy. Pyroptotic cell death can be detected by measuring the release of cytosolic lactate dehydrogenase into the medium. This procedure is simple, cost effective and performed in a 96-well plate format, allowing adaptation for screening. In this manuscript, we show that activation of the NLRP3 inflammasome by nigericin leads to the co-localization of the adaptor protein ASC and active caspase-1, leading to pyroptosis.

We describe the detection of NLRP3 inflammasome activation on cellular basis using fluorescence microscopy and staining for active caspase-1 and the adaptor, ASC. A lactate dehydrogenase release assay is presented to detect pyroptotic lysis on a population basis. These techniques can be adapted to study many aspects of inflammasome biology.

Påvisande av Inflammasome aktivering och Pyroptotic celldöd i murina benmärg-derived makrofager

Inflammasomes are innate immune signaling platforms that are required for the successful control of many pathogenic organisms, but also promote ...

A High-throughput Platform for the Screening of Salmonella spp./Shigella spp.

Fecal-oral transmission of acute gastroenteritis occurs from time to time, especially when people who handled food and water are infected by Salmonella spp./Shigella spp. The gold standard method for the detection of Salmonella spp./Shigella spp. is direct culture but this is labor-intensive and time-consuming. Here, we describe a high-throughput platform for Salmonella spp./Shigella spp. screening, using real-time polymerase chain reaction (PCR) combined with guided culture. There are two major stages: real-time PCR and the guided culture. For the first stage (real-time PCR), we explain each step of the method: sample collection, pre-enrichment, DNA extraction and real-time PCR. If the real-time PCR result is positive, then the second stage (guided culture) is performed: selective culture, biochemical identification and serological characterization. We also illustrate representative results generated from it. The protocol described here would be a valuable platform for the rapid, specific, sensitive and high-throughput screening of Salmonella spp./Shigella spp.

A High-throughput Platform for the Screening of Salmonella spp./Shigella spp.

Salmonella spp./Shigella spp. are common pathogens attributed to diarrhea. Here, we describe a high-throughput platform for the screening of Salmonella spp./Shigella spp. using real-time PCR combined with guided culture.

En hög genomströmning plattform för Screening av Salmonella spp. /Shigella spp.

Fecal-oral transmission of acute gastroenteritis occurs from time to time, especially when people who handled food and water are infected by Salmonella ...