Name: phagosome migration and velocity measured in live primary human macrophages infected with hiv-1
Uploaded: 2016-09-05T15:00:00.000+00:00
Duration: 7 min 32 s
Description: Watch this Scientific Journal Video about Phagosome Migration and Velocity Measured in Live Primary Human Macrophages Infected with HIV-1 at JoVE.com

We thank Dr Jamil Jubrail for reading the manuscript. This work was supported by grants from CNRS, Inserm, Universit&#233; Paris Descartes, Agence Nationale de la Recherche (2011 BSV3 025 02), Fondation pour la Recherche M&#233;dicale (FRM DEQ20130326518 including a doctoral fellowship for GLB) and Agence Nationale de Recherche sur le SIDA et les h&#233;patites virales (ANRS, including a post-doctoral fellowship for CD) to FN. A. Dumas was supported by doctoral fellowships from Universit&#233; Paris Descartes and Sidaction.

Das Protokoll muss in strikter Übereinstimmung mit nationalen und internationalen Gesetzen und örtlichen Vorschriften durchgeführt. Blut von gesunden Spendern, die ihre Zustimmung Blut für Forschungszwecke zu spenden gab wurde von Bluttransfusionszentren erhalten, mit denen die Institutionen Vereinbarung unterzeichnet haben. Besondere Schutzmaßnahmen getroffen werden müssen, wenn menschliches Blut verwendet wird. Experimente mit HIV-1 muss in einem Biosicherheitsstufe 3 oder 2 (BSL-3 oder 2) Labor nach den örtlichen Vorschriften durchgeführt werden. 1. Herstellung von Human-Monozyten abgeleiteten Makrophagen (hMDMs) durch Dichtegradientenzentrifugation und Auswahl durch Adhesion <ol><li> Beginnen Sie mit frischem Blut von gesunden Spendern (9 ml). Verdünne das gesamte Volumen von frischem Blut mit sterilem 1x phosphatgepufferter Kochsalzlösung (PBS) ohne Ca 2+ und Mg 2+ ein Endvolumen von 70 ml zu erhalten , und sanft das verdünnte Blut in zwei 50 ml konische Röhrchen (35 ml pro Röhrchen) hinzuzufügen , oben auf 15 ml eineutral, stark verzweigten, hoher Masse, hydrophile Polysaccharid in Lösung bereits in jedem Röhrchen. </li><li> Zentrifuge beide Rohre von Blut bei 537 xg für 20 min bei 20 ° C ohne Bremse. Dann sammeln Sie die peripheren mononukleären Blutzellen (PBMCs) in den bewölkten Zelle Ring an der Schnittstelle enthalten sind, und übertragen sie in eine neue 50 - ml - Röhrchen mit 15 ml 1x PBS ohne Ca 2+ und Mg 2+. </li><li> Zentrifuge die Zellen bei 218 · g für 5 min bei 20 ° C und das Pellet in 45 ml 1x PBS ohne Ca 2+ und Mg 2+. </li><li> Zentrifuge die Zellen bei 218 · g für 5 min bei 20 ° C, Resuspendieren des Pellets in 10 ml 1x PBS ohne Ca 2+ und Mg 2+ und die Zellen zählen , indem zu einer Endverdünnung von 1/200 in Trypan Blau verdünnt. </li><li> Zentrifugieren der Zellen bei 218 xg für 5 min bei 20 ° C und das Pellet in RPMI (Roswell Park Memorial Institute) 1640-Medium, ergänzt mit 2 mM L-Glutamin und 100 ug / ml Penicillin-Streptomycin 7 x 10 6 PBMCs in 2 ml Medium in jeder Vertiefung einer 6 - Well-Platte pro Vertiefung zu haben. </li><li> Inkubiere die Platten bei 37 ° C mit 5% CO 2 für 2 Std. Nach 2 Stunden wird die Monozyten an den Kunststoff eingehalten. </li><li> Damit frisch isolierten Monozyten in hMDMs zu unterscheiden, aspirieren das Medium und ersetzen Sie es mit 2 ml hMDM Medium (RPMI 1640, 10% decomplemented Fetale Kälberserum (FCS), 2 mM L-Glutamin und 1% Penicillin-Streptomycin), ergänzt mit rekombinantes humanes M-CSF (RHM-CSF) in einer Endkonzentration von 10 ng / ml. </li><li> Inkubieren der Zellen bei 37 ° C mit 5% CO 2 für 11 Tage (Abbildung 1). </li><li> Am Tag 11 das Medium abgenommen und gewaschen werden 2 mal mit 2 ml kaltem hMDM Medium pro Vertiefung. Weiter waschen jeder Vertiefung 2 mal mit 1 ml kaltem 1x PBS. </li><li> Zum Abnehmen ausdifferenzierten hMDMs, waschen Sie sich gut 1 mal mit 1 ml kaltem 1x PBS mit 2 mM ethylenediaminetetraacetatic Säure (EDTA) und die Zellen in 2 ml kaltem 1x PBS mit 2 mM EDTA pro Vertiefung für 15-60 min bei 4 ° C inkubieren. HINWEIS: Alternative Methoden die Zellen existieren (zB Trypsin oder Trypsin-ähnliche Aktivitäten) zu lösen , die gute Ergebnisse 11 geben könnte. </li><li> Nach Ablösung (wird von sanft bis Pipettieren und nach unten in das Bohrloch), um die Zellen zu sammeln und sie in einem 50-ml-Röhrchen auf Eis 10 ml kaltem hMDM Medium enthält. </li><li> Zentrifuge die Zellen bei 218 · g für 5 min bei 20 ° C, das Pellet in 10 ml kaltem hMDM Medium und die Zellen zählen, indem 1/20 in Trypan Blau verdünnt. </li><li> Seed die Zellen bei 1 x 10 6 hMDMs pro 35 mm Mikroskopie Glasbodenschale und Inkubation der Platten bei 37 ° C mit 5% CO 2 für 1 Tag. </li></ol> 2. Herstellung und Quantifizierung von HIV-1-Virus Stocks HINWEIS: NLR4.3 HIV-1 Gag-iGFP (Green Fluorescent Protein) trägt eine R5-trop Umschlag, Geschenk von M. Schindler 10 wird verwendet , Makrophagen zu infizieren und infizierte Zellen in Echtzeit zu sehen. <ol><li> Produzieren viralen Bestände durch Transfektion von humanen embryonalen Nieren 293T Zellen (2 x 10 6 in 100 - mm - Schale) mit 6 ug des entsprechenden provirale DNA Kommerzielle Transfektionsreagenz verwenden. </li><li> Quantifizierung der Infektiosität der Virusstämme mit den Indikatorzellen HeLa TZM-bl (das ß-Galactosidase-Gen unter der Kontrolle des HIV-1 LTR trägt) unter Verwendung von seriellen Verdünnungen der viralen durch eine ß-Galactosidase Färbung der Zellen und das Zählen gefolgt Bestände der blauen Zellen 12. </li></ol> 3. Die Infektion von hMDMs mit HIV-1 <ol><li> Füge das Virus bei einer Multiplizität der Infektion (MOI) von 0,02 bis 0,03 in 1 ml Medium zu hMDM hMDMs (plattierten Zellen in 1,13). Um zu steuern , Brunnen hinzufügen nur 1 ml hMDM Medium und Inkubation das Geschirr bei 37 ° C mit 5% CO 2 für 2 Tage (Abbildung 1). </li><li> Am Tag 2 waschen Sie die Zellen mit hMDM medium 3 Mal und 1 ml frisches hMDM Medium pro Schale. Inkubieren der Zellen bei 37 ° C mit 5% CO 2 für 6 Tage (Abbildung 1). </li></ol> 4. Opsonisierung von roten Blutkörperchen vom Schaf <ol><li> Zur Herstellung von 7 x 10 6 pro Schale SRBCs, wäscht den SRBCs zweimal in 100 ul Lösung , die 0,1% Rinderserumalbumin (BSA) in 1x PBS mit Zentrifugation bei 600 xg für 4 min enthält. </li><li> Resuspendieren der gewaschenen SRBCs in 500 ul 1x PBS / BSA 0,1% mit Kaninchen-IgG anti-SRBCs bei einer sub-agglutinierende Konzentration pro 5 ul SRBCs und Inkubation für 30 min mit Rotation bei RT. HINWEIS: Um die Unter agglutinierend Konzentration von anti-SRBCs IgG, bereiten serielle Verdünnungen von IgG (Stammkonzentration bei 13,1 mg / ml) von 1/50 bis 1 / 25.600 in 20 &amp; mgr; l in einer 96-Well-Platte bestimmen. In 2 x 10 6 SRBCs in 20 &amp; mgr; l in jede Vertiefung und stellte den Teller in einem dunklen Raum während mehrerer Stunden. Der Teil agglutinierende Konzentration ist dieVerdünnung der gut, kurz bevor die gut mit Agglutination (IgG + SRBCs ein Netzwerk bilden). </li><li> Nach der Drehung Zentrifugation der IgG-opsonisierter-SRBCs bei 600 × g für 4 min und Waschen mit 100 ul 1x PBS / BSA 0,1% mit Zentrifugation bei 600 × g für 4 min. </li><li> Resuspendieren der IgG-opsonisiertes-SRBCs in vorgewärmten Phenolrot-freiem RPMI-Medium mit 2 mM L-Glutamin und 1% Penicillin-Streptomycin (1 ml / Schale). </li></ol> 5. Live Cell Videomikroskopie Phagozytose Assay <ol><li> Verwenden eines konfokalen Abbildungssystems , wie beispielsweise einem Spinnplattensystem mit einer Heizkammer ausgerüstet bei 37 ° C mit CO 2 mit Wasser für die Befeuchtung durch eine Flasche vorbei. </li><li> Schalten Sie die Heizkammer vor dem Experiment das Mikroskoptisch zu haben, bei 37 ° C vor dem Beginn des Phagocytose-Assay. Schalten Sie das Mikroskop und Computer, und laden Sie die Bildbearbeitungssoftware. </li><li> Optimieren Sie die Imaging-Einstellungen wie Scangeschwindigkeit, magnificatIon, Auflösung usw. mindestens eine Zelle pro Feld zu haben und Bild eine jede Minute zwischen 60 bis 120 min - Rahmen. HINWEIS: Hier wird die Probe ein Rahmen jede Minute während 60 min mit 63X Objektiv abgebildet wird. </li><li> Setzen Sie die Druckschale auf dem Mikroskoptisch. Stellen Sie den Fokus und die Lage zu finden, nur eine ganze HIV-1-infizierten Makrophagen in das Feld ein. Verwenden Sie geeignete Anregungs- / Emissions-Einstellungen auf der Basis des verwendeten Abbildungssystems und der Sonde. Fügen Sie ein helles Feld (BF) Kanal phagosomes (Abbildung 1II) zu beobachten. Optimieren das Aussehen der verschiedenen Kanalbilder, indem der Prozentsatz von durchgelassenem Licht und die Belichtungszeit eingestellt wird. HINWEIS: Hier NLR4.3 HIV-1 Gag-iGFP war begeistert , eine 491 - nm - Laser mit 50 ms Zeitbelichtung mit 20% der Laser (Abbildung 1 i) verwendet wird . </li><li> Nehmen Sie die Bildschale und 1 ml SRBC - Suspension bei 7 x 10 6 SRBCs / ml in die Schale (Abbildung 1). </li><li> Zentrifuge bei 500 × g für2 min bei RT Phagozytose, notieren Sie die Zeit am Ende dieser Zentrifugation und Rück die Schale auf die Bühne zu synchronisieren. </li><li> Optimierung des Fokus und capture GFP und BF Bilder in Z-Stapel (über die Dicke der Zelle mit einem Schritt-Abstand von 0,3 um - in der Regel 20-Ebenen) mindestens 1 Stunde jede Minute für. Speichern Sie die Zeitraffer-Video im nativen Dateiformat des verwendeten Abbildungssystems. HINWEIS: Hier Zeitraffer-Filme im nativen Format gespeichert wurden, * .STK Dateien. </li></ol> 6. Die Analyse der Zeitraffer-Filme <ol><li> Für Videobearbeitung, klicken Sie auf das Dropdown-Menü &quot;Apps&quot; und auf der Registerkarte &quot;Bewertungs Multi Dimensional Data&quot; in der Video-Editing-Software. <ol><li> Um die Datei zu öffnen, klicken Sie auf &quot;Select Base-Datei&quot; und dann auf &quot;Select Directory&quot;. In der &quot;Datensätze&quot; Feld, wählen Sie den Erwerb (in .ND-Format) zu analysieren, und klicken Sie auf &quot;Ansicht&quot;. Die Daten werden in einer Tabelle mit der Zeit in der Spalte ein repräsentiertd Z-Plan in der Leitung. </li><li> Um die Infektion in einer Z-Projektion darstellen (Abbildung 2, links Platten), wählen Sie 491 nm Wellenlänge im &quot;Wavelengths&quot; und klicken Sie auf den &quot;Z Projektion&quot; Tab mit &quot;allen Ebenen&quot;. </li><li> Um eine zeitliche Abfolge analysieren, BF Wellenlänge im &quot;Wavelengths&quot; ein und wählen Sie die optimale Ebene , auf der Z-Achse wählen zu externen SRBCs unterscheiden (Abbildung 2, roten Pfeilspitze), interne SRBCs (Abbildung 2, roter Kreis) und den Kern ( Abbildung 2, blauer Kreis). </li><li> Um die Videomontagen speichern, klicken Sie auf &quot;Auswahl [X]&quot; und dann auf &quot;Load Image (s)&quot;. Schließlich die geladenen Bilder in .tif-Format speichern und Software als nächstes auf ImageJ öffnen. </li></ol></li><li> Verwenden Sie das Plugin &quot;Manuelle Spur&quot; auf der ImageJ Software die Position des Kerns und die verschiedenen phagosomes in BF Kanal (Abbildung 3) beobachtet zu messen. <ol><li> Download das &quot;Manual-Tracking&quot; Plugin auf der ImageJ Website. Auf ImageJ, öffnen Sie das Plugin und die Bildfolge analysiert werden (Abbildung 3, Schritt 1 und 2). </li><li> Geben Sie die Einstellungen wie &quot;Time Interval&quot; , die zwischen benachbarten Rahmen Höhe der Zeit darstellt und die &quot;x / y - Kalibrierung&quot; , die den Abstand pro Pixel darstellt (Abbildung 3, Schritt 3). HINWEIS: Hier speichern Sie die Bildfolge mit einem Zeitintervall von 1 Minute zwischen jedem Rahmen und x / y Kalibrierung von 0,205 &amp; mgr; m , da die 63X - Zoom und eine Kamera mit Pixelgröße von 6,45 x 6,45 &amp; mgr; m 2 verwendet werden. </li><li> Um die Verfolgung zu starten, klicken Sie auf &quot;Add Track&quot; (Abbildung 3, Schritt 4) und klicken Sie auf ein SRBC Zentrum beim ersten Mal , wenn er internalisiert wird. Das nächste Bild erscheint automatisch. </li><li> Weiter auf der SRBC - Center in allen Frames klicken verschiedenen Positionen während der Zeit zu haben (Abbildung 3, Schritt 6 im roten Kasten). <ol><li> Starten Sie den Kern zu verfolgen seine Position durch einen Klick auf das Zentrum in allen Frames zu haben. Spur folgen die phagosomes (durch seine Mitte zu klicken) nacheinander zu der Zeit (Rahmen) ihrer Verinnerlichung, unterscheidet sich in Abhängigkeit von SRBCs. Der Einfachheit halber SRBC auf BF - Kanal zu sehen, verwenden Sie die &quot;Helligkeit und Kontrast&quot; Fenster während der Tracking (Abbildung 3, Schritt 5). </li></ol></li><li> Zwischen jedem SRBC - Tracking, klicken Sie auf &quot;Add Track&quot; (Abbildung 3, Schritt 4) eine neue Spur zu haben. Die Anzahl der Tracking wird in der zweiten Spalte &quot;Track n °&quot; der Ergebnistabelle (Abbildung 3, Schritt 6) geändert werden. </li><li> Speichern der Daten in einer Tabelle mit dem nächsten Schritt der Analyse fortzusetzen. </li></ol></li><li> Verwenden , Tabellenkalkulationssoftware , die zurückgelegte Strecke von Phagosomen enthält SRBCs Richtung Kern und der Geschwindigkeit der Phagosomen während der ersten 5 min nach der Internalisierung von SRBCs zu berechnen (FiAbbildung 4). <ol><li> Öffnen Sie die Tabelle Tabelle und eine neue Tabellenkalkulationsdatei. Transfer in diese neue Datei nur die folgenden Parameter, die Zeit, die x- und y- Koordinate des Kerns und alle SRBCs (4A). </li><li> Um den Abstand zwischen SRBCs berechnen und den Kern nur mit ihren Koordinaten betrachten den Kern und einen SRBC in einem XY-Koordinatenebene (4B). HINWEIS: Der Abstand zwischen zwei Punkten ist die Länge der Strecke, die sie verbinden. In der Ebene wird der Abstand zwischen SRBC und dem Kern durch den Satz des Pythagoras gegeben. <ol><li> Wenn c (der Abstand zwischen dem Kern und dem SRBC) , um die Länge der Hypotenuse und A und b die Längen der beiden anderen Seiten bezeichnen exprimieren Pythagoras &#39;Theorem als pythagoreischen Gleichung: <img alt="Gleichung 1" src="/files/ftp_upload/54568/54568eq1.jpg" /> HINWEIS: In der gleichen Zeit auf der orthonormal, der horizontale Abstanda (x - x Kern SRBC) und der vertikale Abstand b (y -y Kern SRBC). </li><li> So berechnen Sie den Abstand zwischen dem Kern und dem SRBC (4A, lila Box) von: <img alt="Gleichung 2" src="/files/ftp_upload/54568/54568eq2.jpg" /> HINWEIS: Multiplizieren der Wert, der Abstand (in Pixeln) von x / y-Kalibrierung den Abstand in &amp; mgr; m zu haben. Hier wird die x / y-Kalibrierung ist 0,205 &amp; mgr; m. </li><li> Zu jedem Zeitpunkt, zu subtrahieren , den Abstand zwischen dem Kern und dem SRBC auf den Anfangsabstand (4C). </li><li> Zeichnen Sie die Messung gegen die Zeit für den ersten 5 min. Tragen Sie eine lineare Trendlinie (5A) auf dem Grundstück und bestimmen die Steigung der linearen Trend-Linie, die die phagosome Geschwindigkeit in Richtung des Kerns während der ersten 5 Minuten nach der SRBC Internalisierung darstellt. </li><li> Collate die Daten den Durchschnitt und die statistischen Fehler von zu berechnendie Geschwindigkeitswerte und sie in geeigneter Form zeichnen die entsprechende Software (5B) verwendet wird . </li></ol></li></ol></li></ol>

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The authors have nothing to disclose.

Diese Technik hat mehrere wichtige Schritte. Zum einen ist die Herstellung von hMDMs und ihre Infektion durch HIV-1 wichtig, da der Prozentsatz der Infektion Spender abhängt. Bemerkenswert ist , haben wir beschlossen , Makrophagen zu verwenden , die in vitro vor der Infektion nicht polarisiert sind, weil der Status der Makrophagen durch das Virus in vivo angetroffen möglicherweise nicht gut , so weit charakterisiert. Wir überprüften die Expression verschiedener Oberflächenmarker, was darauf hinwei...

Macrophages play a major role in the innate immune system and in homeostasis. They are professional phagocytes that internalize and eliminate pathogens and debris by a process called phagocytosis 1,2. The phagosome, the closed compartment that forms after the engulfment of particulate material, undergoes a series of fusion and fission events with endocytic compartments, leading to a degradative compartment called the phagolysosome. This compartment has an acidic pH, due to the acquisition of proton-pumping v-ATPases, contains hydrolytic enzymes and is enriched in lysosomal-associated membrane proteins (LAMPs). The maturation of phagosomes is accompanied by their migration on microtubules 3,4 towards the cell center to reach a perinuclear location where lysosomes are accumulated.
Many pathogens have been reported to hijack phagosome maturation, including bacteria with intracellular lifestyles that modify the vacuolar environment where they reside 5. The Human Immunodeficiency Virus (HIV)-1 targets macrophages in addition to T cells. As macrophages are resistant to the cytopathic effects of the virus, unlike T cells, they can be considered as a reservoir for the virus. In addition, macrophages infected with HIV-1 show defective phagocytic functions and contribute to the emergence of opportunistic diseases. In particular, severe invasive non-typhoidal Salmonella disease caused by Salmonella Typhimurium ST313 has been prevalent for the last three decades in sub-Saharan African children or adults infected with HIV 6. It has been estimated that the risk of developing tuberculosis is more than 20 times greater in people living with HIV than among those without HIV infection. 
For all these reasons, it is important to better define the molecular mechanisms underlying the phagocytic defects in HIV-infected macrophages. We have shown that the uptake of particulate material, opsonized particles, bacteria or fungi, was inhibited in HIV-infected macrophages 7. Given that this inhibition is partial, we then set out to analyze the fate of the internalized phagosomes in HIV infected human macrophages 8. Because phagosome maturation is tightly connected with migration to the cell center and fusion with lysosomes, a defect in phagosomal maturation can be due to modifications of the trafficking modalities in the infected cell. The method described here uses IgG-opsonized Sheep Red Blood Cells (IgG-SRBCs) as a model to target receptor-mediated phagocytosis and in particular receptors for the Fc portion of immunoglobulins (FcR). These particles are easier to image in bright field (BF) than latex beads because extracellular and intracellular SRBCs show different refraction properties 9. To measure the velocity of phagosomes moving towards the nucleus in HIV-infected macrophages, we used a fluorescent virus 10 and set up a simple manual tracking method that is described here. The method does not require advanced programming and simply uses ImageJ. It is amenable to adherent cells and any type of particle or pathogen that can be visualized with bright field microscopy or with fluorescent imaging.

<table><tbody><tr><td>Falcon 100 mm TC-Treated Cell Culture Dish</td><td>Corning</td><td>353003</td><td>For viral production</td></tr><tr><td>Glass Bottom Dishes 35 mm uncoated 1.5</td><td>MatTek corporation</td><td>P35G-1.5-14-C Case</td><td>For acquisition</td></tr><tr><td>Falcon Tissue Culture Plates 6-well</td><td>Thermo Fischer Scientific</td><td>Corning. Inc. 353934</td><td>For human monocyte-derived macrophages</td></tr><tr><td>Ficoll-Plaque PLUS</td><td>Dominique Dutscher</td><td>17-1440-03</td><td>a neutral, highly branched, high-mass, hydrophilic polysaccharide in solution for density centrifugation</td></tr><tr><td>DPBS, no calcium, no magnesium</td><td>Thermo Fischer Scientific</td><td>14190-094</td><td>RT</td></tr><tr><td>Dulbecco&#039;s Modified Eagle Medium (DMEM) 1x, liquid (High Glucose)</td><td>GIBCO, Molecular probes</td><td>31966-021</td><td>Conserved at 4 &amp;deg;C ; for HEK cells culture</td></tr><tr><td>RPMI 1640 medium GLUTAMAX&amp;nbsp; Supplement</td><td>Life technologies</td><td>61870-010</td><td>Conserved at 4 &amp;deg;C; for hMDMs culture</td></tr><tr><td>F&amp;oelig;tal Calf Serum (FCS)&amp;nbsp;</td><td>Eurobio</td><td>CVFSVF0001</td><td>Conserved at -20 &amp;deg;C ; decomplemented</td></tr><tr><td>Penicillin-Streptomycin (10,000 U/ml)</td><td>Thermo Fischer Scientific</td><td>15140-122</td><td>Conserved at -20 &amp;deg;C ; for hMDMs culture</td></tr><tr><td>RPMI 1640 medium, no phenol red (10x 500 ml)</td><td>Life technologies</td><td>11835-105</td><td>Warm in 37 &amp;deg;C water bath before use ; for phagocytosis assay</td></tr><tr><td>FuGENE6 Transfection Reagent</td><td>Promega</td><td>E2692</td><td>Conserved at 4 &amp;deg;C ; for viral production</td></tr><tr><td>Sheep red blood cells (SRBCs)</td><td>Eurobio</td><td>DSGMTN00-0Q</td><td>Conserved in Alsever buffer at 4 &amp;deg;C before use</td></tr><tr><td>Anti-sheep red blood cells IgG</td><td>MP Biomedicals</td><td>55806</td><td>Conserved at 4 &amp;deg;C</td></tr><tr><td>Bovine Serum Albumin heat shock fraction, pH 7, &amp;ge;98%&amp;nbsp;</td><td>Sigma</td><td>A7906</td><td>Conserved at -20 &amp;deg;C</td></tr><tr><td>Inverted microscope DMI600</td><td>Leica</td><td></td><td></td></tr><tr><td>Confocal Spinning Disk Unit&amp;nbsp; CSU-X1M1</td><td>Yokogawa</td><td></td><td></td></tr><tr><td>491 nm 50 mW laser</td><td>COBOLT CALYPSO</td><td></td><td></td></tr><tr><td>HCX PL APO CS Objectif</td><td>Leica</td><td></td><td>Objective lens ; Magnification 100X ; Numerical aperture 1.40 ; Immersion oil</td></tr><tr><td>CoolSnap HQ2 (FireWire) Camera</td><td>Photometrics</td><td></td><td>Pixel size 6.45 &amp;micro;m x 6.45 &amp;micro;m ; Definition 1,392 x 1,040 ; Encoding the image in 14 Bit</td></tr><tr><td>Metamorph 7.7.5 software</td><td>Molecular Devices</td><td></td><td>For the control of the microscope</td></tr><tr><td>GraphPad Prism software</td><td></td><td></td><td>For the statistics analysis</td></tr></tbody></table>

phagosome migration and velocity measured in live primary human macrophages infected with hiv-1

Macrophages are phagocytic cells that play a major role at the crossroads between innate and specific immunity. They can be infected by the human immunodeficiency virus (HIV)-1 and because of their resistance to its cytopathic effects they can be considered to be persistent viral reservoirs. In addition, HIV-infected macrophages exhibit defective functions that contribute to the development of opportunistic diseases.
The exact mechanism by which HIV-1 impairs the phagocytic response of macrophages was unknown. We had previously shown that the uptake of various particulate material by macrophages was inhibited when they were infected with HIV-1. This inhibition was only partial and phagosomes did form within HIV-infected macrophages. Therefore, we focused on analyzing the fate of these phagosomes. Phagosome maturation is accompanied by migration of these compartments towards the cell center, where they fuse with lysosomes, generating phagolysosomes, responsible for degradation of the ingested material. We used IgG-opsonized Sheep Red Blood Cells as a target for phagocytosis. To measure the speed of centripetal movement of phagosomes in individual HIV-infected macrophages, we used a combination of bright field and fluorescence confocal microscopy. We established a method to calculate the distance of phagosomes towards the nucleus, and then to calculate the velocity of the phagosomes. HIV-infected cells were identified thanks to a GFP-expressing virus, but the method is applicable to non-infected cells or any type of infection or treatment.

FcR-vermittelte Phagozytose durch HIV-1-infizierten und nicht-infizierten hMDMs wird hier beschrieben unter Verwendung von IgG-opsonisiertes SRBCs als Modellzielen (Abbildung 1). Die kritischen Schritte dieses Protokolls sind die Herstellung von hMDMs und die Infektion mit HIV-1. Tatsächlich variiert die Ausbeute und die Qualität der differenzierten Makrophagen unter den Gebern sowie die Infektionsrate mit einem Wirkungsgrad im Bereich von 10-40%. Darüber hinaus ist d...

Watch this Scientific Journal Video about Phagosome Migration and Velocity Measured in Live Primary Human Macrophages Infected with HIV-1 at JoVE.com

Phagosome Migration and Velocity Measured in Live Primary Human Macrophages Infected with HIV-1

We describe a method to measure the velocity of phagosomes moving towards the cell center in living cells infected with or without the human immunodeficiency virus (HIV) type 1, using spinning disk confocal fluorescence microscopy to identify fluorescent infected cells and bright field microscopy to detect phagosomes.

Phagosom Migration und Geschwindigkeit gemessen in Live-primären humanen Makrophagen mit HIV-1 infizierten

Macrophages are phagocytic cells that play a major role at the crossroads between innate and specific immunity. They can be infected by the human ...

phagosome-migration-velocity-measured-live-primary-human-macrophages

Research

JoVE Journal

Immunology and Infection

8.1K Aufrufe.  Inserm U1016, Institut Cochin, CNRS UMR 8104, Université Paris Descartes, Sorbonne Paris Cité. We describe a method to measure the velocity of phagosomes moving towards the cell center in living cells infected with or without the human immunodeficiency virus (HIV) type 1, using spinning disk confocal fluorescence microscopy to identify fluorescent infected cells and bright field microscopy to detect phagosomes. 

Serie: Phagosome Migration and Velocity Measured in Live Primary Human Macrophages Infected with HIV-1

Visualizing Cell-to-cell Transfer of HIV using Fluorescent Clones of HIV and Live Confocal Microscopy

By fusing the green fluorescent protein to their favorite proteins, biologists now have the ability to study living complex cellular processes using fluorescence video microscopy. To track the movements of the human immunodeficiency virus core protein during cell-to-cell transmission of human immunodeficiency virus, we have GFP-tagged the Gag protein in the context of an infectious molecular clone of HIV, called HIV Gag-iGFP. We study this viral clone using video confocal microscopy. In the following visualized experiment, we transfect a human T cell line with HIV Gag-iGFP, and we use fluorescently labeled uninfected CD4+ T cells to serve as target cells for the virus. Using the different fluorescent labels we can readily follow viral production and transport across intercellular structures called virological synapses. Simple gas permeable imaging chambers allow us to observe synapses with live confocal microscopy from minutes to days. These approaches can be used to track viral proteins as they move in from one cell to the next.

This visualized experiment is a guide for utilizing a fluorescent molecular clone of HIV for live confocal imaging experiments.

Visualizing Zell-Zell-Transfer von HIV unter Verwendung von fluoreszierenden Klone von HIV und Live-konfokale Mikroskopie

By fusing the green fluorescent protein to their favorite proteins, biologists now have the ability to study living complex cellular processes using ...

Forschung

Immunologie und Infektion

Live-cell Video Microscopy of Fungal Pathogen Phagocytosis

Phagocytic clearance of fungal pathogens, and microorganisms more generally, may be considered to consist of four distinct stages: (i) migration of phagocytes to the site where pathogens are located; (ii) recognition of pathogen-associated molecular patterns (PAMPs) through pattern recognition receptors (PRRs); (iii) engulfment of microorganisms bound to the phagocyte cell membrane, and (iv) processing of engulfed cells within maturing phagosomes and digestion of the ingested particle. Studies that assess phagocytosis in its entirety are informative1, 2, 3, 4, 5 but are limited in that they do not normally break the process down into migration, engulfment and phagosome maturation, which may be affected differentially. Furthermore, such studies assess uptake as a single event, rather than as a continuous dynamic process. We have recently developed advanced live-cell imaging technologies, and have combined these with genetic functional analysis of both pathogen and host cells to create a cross-disciplinary platform for the analysis of innate immune cell function and fungal pathogenesis. These studies have revealed novel aspects of phagocytosis that could only be observed using systematic temporal analysis of the molecular and cellular interactions between human phagocytes and fungal pathogens and infectious microorganisms more generally. For example, we have begun to define the following: (a) the components of the cell surface required for each stage of the process of recognition, engulfment and killing of fungal cells1, 6, 7, 8; (b) how surface geometry influences the efficiency of macrophage uptake and killing of yeast and hyphal cells7; and (c) how engulfment leads to alteration of the cell cycle and behavior of macrophages 9, 10.
In contrast to single time point snapshots, live-cell video microscopy enables a wide variety of host cells and pathogens to be studied as continuous sequences over lengthy time periods, providing spatial and temporal information on a broad range of dynamic processes, including cell migration, replication and vesicular trafficking. Here we describe in detail how to prepare host and fungal cells, and to conduct the video microscopy experiments. These methods can provide a user-guide for future studies with other phagocytes and microorganisms.

We describe methods for live-cell video microscopy of Candida albicans phagocytosis by macrophages. These methods enable stage-specific analysis of macrophage migration, recognition, engulfment and phagosome maturation and reveal novel aspects of phagocytosis.

Live-cell Video Mikroskopie Pilzpathogenentwicklung Phagozytose

Phagocytic clearance of fungal pathogens, and microorganisms more generally, may be considered to consist of four distinct stages: (i) migration of ...

Study of Phagolysosome Biogenesis in Live Macrophages

Phagocytic cells play a major role in the innate immune system by removing and eliminating invading microorganisms in their phagosomes. Phagosome maturation is the complex and tightly regulated process during which a nascent phagosome undergoes drastic transformation through well-orchestrated interactions with various cellular organelles and compartments in the cytoplasm. This process, which is essential for the physiological function of phagocytic cells by endowing phagosomes with their lytic and bactericidal properties, culminates in fusion of phagosomes with lysosomes and biogenesis of phagolysosomes which is considered to be the last and critical stage of maturation for phagosomes. In this report, we describe a live cell imaging based method for qualitative and quantitative analysis of the dynamic process of lysosome to phagosome content delivery, which is a hallmark of phagolysosome biogenesis. This approach uses IgG-coated microbeads as a model for phagocytosis and fluorophore-conjugated dextran molecules as a luminal lysosomal cargo probe, in order to follow the dynamic delivery of lysosmal content to the phagosomes in real time in live macrophages using time-lapse imaging and confocal laser scanning microscopy. Here we describe in detail the background, the preparation steps and the step-by-step experimental setup to enable easy and precise deployment of this method in other labs. Our described method is simple, robust, and most importantly, can be easily adapted to study phagosomal interactions and maturation in different systems and under various experimental settings such as use of various phagocytic cells types, loss-of-function experiments, different probes, and phagocytic particles.

Studium der Biogenese Phagolysosom im Live-Makrophagen

Phagocytic cells play a major role in the innate immune system by removing and eliminating invading microorganisms in their phagosomes. Phagosome ...

High Throughput Fluorometric Technique for Assessment of Macrophage Phagocytosis and Actin Polymerization

The goal of fluorometric analysis is to serve as an efficient, cost effective, high throughput method of analyzing phagocytosis and other cellular processes. This technique can be used on a variety of cell types, both adherent and non-adherent, to examine a variety of cellular properties. When studying phagocytosis, fluorometric technique utilizes phagocytic cell types such as macrophages, and fluorescently labeled opsonized particles whose fluorescence can be extinguished in the presence of trypan blue. Following plating of adherent macrophages in 96-well plates, fluorescent particles (green or red) are administered and cells are allowed to phagocytose for varied amounts of time. Following internalization of fluorescent particles, cells are washed with trypan blue, which facilitates extinction of fluorescent signal from bacteria which are not internalized, or are merely adhering to the cell surface. Following the trypan wash, cells are washed with PBS, fixed, and stained with DAPI (nuclear blue fluorescent label), which serves to label nuclei of cells. By a simple fluorometric quantification through plate reading of nuclear (blue) or particle (red/green) fluorescence we can examine the ratio of relative fluorescence units of green:blue and determine a phagocytic index indicative of amount of fluorescent bacteria internalized per cell. The duration of assay using a 96-well method and multichannel pipettes for washing, from end of phagocytosis to end of data acquisition, is less than 45 min. Flow cytometry could be used in a similar manner but the advantage of fluorometry is its high throughput, rapid method of assessment with minimal manipulation of samples and quick quantification of fluorescent intensity per cell. Similar strategies can be applied to non adherent cells, live labeled bacteria, actin polymerization, and essentially any process utilizing fluorescence. Therefore, fluorometry is a promising method for its low cost, high throughput capabilities in the study of cellular processes.

Here we present a protocol to quantify phagocytosis of fluorescent particles by adherent macrophage cell line using a fluorometric method. This method facilitates a high throughput quantification of particle internalization as well as the resulting actin polymerization.

High Throughput Fluorometric Technik zur Bewertung der Makrophagen-Phagozytose und Aktinpolymerisation

The goal of fluorometric analysis is to serve as an efficient, cost effective, high throughput method of analyzing phagocytosis and other cellular ...

"Phagosome Closure Assay" to Visualize Phagosome Formation in Three Dimensions Using Total Internal Reflection Fluorescent Microscopy (TIRFM)

Phagocytosis is a mechanism used by specialized cells to internalize and eliminate microorganisms or cellular debris. It relies on profound rearrangements of the actin cytoskeleton that is the driving force for plasma membrane extension around the particle. In addition, efficient engulfment of large material relies on focal exocytosis of intracellular compartments. This process is highly dynamic and numerous molecular players have been described to have a role during phagocytic cup formation. The precise regulation in time and space of all of these molecules, however, remains elusive. In addition, the last step of phagosome closure has been very difficult to observe because inhibition by RNA interference or dominant negative mutants often results in stalled phagocytic cup formation. 
We have set up a dedicated experimental approach using total internal reflection fluorescence microscopy (TIRFM) combined with epifluorescence to monitor step by step the extension of pseudopods and their tips in a phagosome growing around a particle loosely bound to a coverslip. This method allows us to observe, with high resolution the very tips of the pseudopods and their fusion during closure of the phagosome in living cells for two different fluorescently tagged proteins at the same time.

"Phagosome Closure Assay" to Visualize Phagosome Formation in Three Dimensions Using Total Internal Reflection Fluorescent Microscopy TIRFM

We describe an experimental setup to visualize with unprecedented high resolution phagosome formation and closure in three dimensions in living macrophages, using total internal reflection fluorescence microscopy. It allows monitoring of the base of the phagocytic cup, the extending pseudopods, as well as the precise site of phagosome scission.

&quot;Phagosomen Closure Assay&quot; zu visualisieren Phagosomen Formation in drei Dimensionen Mit Total Internal Reflection Fluoreszenz-Mikroskopie (TIRFM)

Phagocytosis is a mechanism used by specialized cells to internalize and eliminate microorganisms or cellular debris. It relies on profound rearrangements ...

Time-lapse 3D Imaging of Phagocytosis by Mouse Macrophages

Phagocytosis plays a key role in host defense, as well as in tissue development and maintenance, and involves rapid, receptor-mediated rearrangements of the actin cytoskeleton to capture, envelop and engulf large particles. Although phagocytic receptors, downstream signaling pathways, and effectors, such as Rho GTPases, have been identified, the dynamic cytoskeletal remodeling of specific receptor-mediated phagocytic events remain unclear. Four decades ago, two distinct mechanisms of phagocytosis, exemplified by Fc&#947; receptor (Fc&#947;R)- and complement receptor (CR)-mediated phagocytosis, were identified using scanning electron microscopy. Binding of immunoglobulin G (IgG)-opsonized particles to Fc&#947;Rs triggers the protrusion of thin membrane extensions, which initially form a so-called phagocytic cup around the particle before it becomes completely enclosed and retracted into the cell. In contrast, complement opsonized particles appear to sink into the phagocyte following binding to complement receptors. These two modes of phagocytosis, phagocytic cup formation and sinking in, have become well established in the literature. However, the distinctions between the two modes have become blurred by reports that complement receptor-mediated phagocytosis may induce various membrane protrusions. With the availability of high resolution imaging techniques, phagocytosis assays are required that allow real-time 3D (three dimensional) visualization of how specific phagocytic receptors mediate the uptake of individual particles. More commonly used approaches for the study of phagocytosis, such as end-point assays, miss the opportunity to understand what is happening at the interface of particles and phagocytes. Here we describe phagocytic assays, using time-lapse spinning disk confocal microscopy, that allow 3D imaging of single phagocytic events. In addition, we describe assays to unambiguously image Fc&#947; receptor- or complement receptor-mediated phagocytosis.

Here we describe methods using spinning disk confocal microscopy to image single phagocytic events by mouse resident peritoneal macrophages. The protocols can be extended to other phagocytic cells.

Time-Lapse 3D-Bildgebung der Phagozytose durch Makrophagen der Maus

Phagocytosis plays a key role in host defense, as well as in tissue development and maintenance, and involves rapid, receptor-mediated rearrangements of ...

Investigating the Phagocytosis of Leishmania using Confocal Microscopy

Phagocytosis is an orchestrated process that involves distinct steps: recognition, binding, and internalization. Professional phagocytes take up Leishmania parasites by phagocytosis, consisting of recognizing ligands on parasite surfaces by multiple host cell receptors. Binding of Leishmania to macrophage membranes occurs through complement receptor type 1 (CR1) and complement receptor type 3 (CR3) and Pattern Recognition Receptors. Lipophosphoglycan (LPG) and 63 kDa glycoprotein (gp63) are the main ligands involved in macrophage-Leishmania interactions. Following the initial recognition of parasite ligands by host cell receptors, parasites become internalized, survive, and multiply within parasitophorous vacuoles. The maturation process of Leishmania-induced vacuoles involves the acquisition of molecules from intracellular vesicles, including monomeric G protein Rab 5 and Rab 7, lysosomal associated membrane protein 1 (LAMP-1), lysosomal associated membrane protein 2 (LAMP-2), and microtubule-associated protein 1A/1B-light chain 3 (LC3).
Here, we describe methods to evaluate the early events occurring during Leishmania interaction with the host cells using confocal microscopy, including (i) binding (ii) internalization, and (iii) phagosome maturation. By adding to the body of knowledge surrounding these determinants of infection outcome, we hope to improve the understanding of the pathogenesis of Leishmania infection and support the eventual search for novel chemotherapeutic targets.

Investigating the Phagocytosis of Leishmania using Confocal Microscopy

The mechanism associated with phagocytosis in Leishmania infection remains poorly understood. Here, we describe methods to evaluate the early events occurring during Leishmania interaction with the host cells.

Untersuchung der Phagozytose der Leishmanie mittels konfokaler Mikroskopie

Phagocytosis is an orchestrated process that involves distinct steps: recognition, binding, and internalization. Professional phagocytes take up ...

Obtainment of Macrophages from Human Monocytes to Assess Leishmania braziliensis Infection Rate and Innate Host Immune Response

Macrophages are multifunctional cells essential to the immune system function, and the primary host cell in Leishmania braziliensis (Lb) infection. These cells are specialized in microorganism recognition and phagocytosis, but also activate other immune cells and present antigens, as well as promote inflammation and tissue repair. Here, we describe a protocol to obtain mononuclear cells from peripheral blood (PBMC) of healthy donors to separate monocytes that then differentiate into macrophages. These cells can then be infected in vitro at different Lb concentrations to evaluate the ability to control infection, as well as evaluate host cell immune response, which can be measured by several methods. PBMCs were first isolated by centrifuging with Ficoll-Hypaque gradient and then plated to allow monocytes to adhere to culture plates; non-adherent cells were removed by washing. Next, adherent cells were cultured with macrophage-colony stimulating factor (M-CSF) for 7 days to induce macrophage differentiation. We suggest plating 2 x 106&#160;cells per well on 24-well plates in order to obtain 2 x 105&#160;macrophages. Fully differentiated macrophages can then be infected with Lb for 4 or 24 hours. This protocol results in a significant percentage of infected cells, which can be assessed by optical or fluorescence microscopy. In addition to infection index, parasite load can be measured by counting the numbers of parasites inside each cell. Further molecular and functional assays can also be performed in culture supernatants or within the macrophages themselves, which allows this protocol to be applied in a variety of contexts and also adapted to other intracellular parasite species.

Obtainment of Macrophages from Human Monocytes to Assess Leishmania braziliensis Infection Rate and Innate Host Immune Response

This protocol describes the process for obtaining human macrophages from monocytes for infection with Leishmania braziliensis. It also allows researchers to evaluate infection rate and parasite viability, ROS production by fluorescence microscopy, and the production of inflammatory mediators in culture supernatants to investigate macrophage response to infection.

Macrophages are multifunctional cells essential to the immune system function, and the primary host cell in Leishmania braziliensis (Lb) infection. These ...

Real-Time Imaging of Macrophage Phagocytosis of IgG-Opsonized Red Blood Cells

Source: Horsthemke, M., et al. <a href="https://app.jove.com/v/57566">Time-lapse 3D Imaging of Phagocytosis by Mouse Macrophages.</a> J. Vis. Exp. (2018)
This video demonstrates an assay to monitor independent macrophage-mediated red blood cell (RBC) phagocytosis events. Mouse immunoglobulin G (IgG)-opsonized human RBCs are incubated with mouse macrophages and observed under a confocal microscope. The RBCs are engulfed by macrophages via a phagocytic cup formation and targeted for lysosomal degradation.

Echtzeit-Bildgebung der Makrophagen-Phagozytose von IgG-opsonisierten roten Blutkörperchen

Source: Horsthemke, M., et al. Time-lapse 3D Imaging of Phagocytosis by Mouse Macrophages. J. Vis. Exp. (2018)
This video demonstrates an assay to monitor ...

JoVE Encyclopedia of Experiments

Immunology

Immunodiagnostics

Specialized Assays

TIRF Microscopy-Based Visualization of Phagosome Formation and Closure

Source: Marie-Ana&#239;s, F., et al. <a href="https://app.jove.com/v/54470">&#34;Phagosome Closure Assay&#34; to Visualize Phagosome Formation in Three Dimensions Using Total Internal Reflection Fluorescent Microscopy (TIRFM).</a> J. Vis. Exp. (2016).
This video demonstrates a high-resolution total internal reflection fluorescence (TIRF) microscopy technique for real-time visualization of phagosome formation and closure during macrophage-mediated phagocytosis of IgG-opsonized red blood cells (RBCs) attached to the surface of a glass bottom dish. The macrophages extend pseudopodia around the RBCs and engulf them inside the phagosomes, detaching them from the glass surface.

Phagosom Migration und Geschwindigkeit gemessen in Live-primären humanen Makrophagen mit HIV-1 infizierten

Zusammenfassung

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High Throughput Fluorometric Technik zur Bewertung der Makrophagen-Phagozytose und Aktinpolymerisation

"Phagosomen Closure Assay" zu visualisieren Phagosomen Formation in drei Dimensionen Mit Total Internal Reflection Fluoreszenz-Mikroskopie (TIRFM)

Time-Lapse 3D-Bildgebung der Phagozytose durch Makrophagen der Maus

Untersuchung der Phagozytose der Leishmanie mittels konfokaler Mikroskopie

Obtainment of Macrophages from Human Monocytes to Assess Leishmania braziliensis Infection Rate and Innate Host Immune Response

Echtzeit-Bildgebung der Makrophagen-Phagozytose von IgG-opsonisierten roten Blutkörperchen

TIRF-Mikroskopie-basierte Visualisierung der Phagosomenbildung und des Phagosomenverschlusses