Diese Arbeit wurde unterstützt durch die Fakultät Forschung aus der College of Arts and Sciences Dean Büro an der University of Hartford gewährt.

Während der Studie Tierpflege und Behandlung National Institutes of Health Policy eingehalten, wurden in Übereinstimmung mit Richtlinien und wurden von der University of Hartford institutionelle Animal Tierpflege und Use Committee genehmigt.
(1) die Mitnahme von Tieren
Hinweis: Zwanzig Wochen alten männlichen B6129SF2/J Mäusen werden in der Studie verwendet.
<ol><li>Mitzureißen Mäuse auf ein 12 h Licht (standard Overhead weißes Licht) / 12 h Dunkel-Zyklus für 2 Wochen vor dem Experiment. Hinweis: Hier Zeitgeber Zeit (ZT) 0 entspricht, leuchtet und ZT12 Licht aus, unter Beibehaltung aller anderen Umweltfaktoren (z.B. Nahrungsmittel, Wasser und Raumtemperatur) konstant 21.</li>
</ol>2. Vorbereitung der Instrumente, Kultur, und Herausforderung Medium
<ol><li>Autoklaven-Zange und sezierenden Scheren. Wickeln Sie Paare von satiniertem Objektträger in Aluminiumfolie und Autoklaven.</li>
	<li>Bereiten Sie Kulturmedium durch Zugabe von fetalen bovine Serum (FBS), RPMI 1640, eine Endkonzentration von 10 %. Vorbereitung 10 mL Medium Herausforderung in 50 mL Röhrchen durch Hinzufügen der folgenden PAMPs zu dem Kulturmedium (RPMI mit 10 % FBS); LPS (5 µg/mL), ODN1826 (5 µg/mL), Hitze-getötet Listeria Monocytogenes (108 HKLM/mL), oder ein anderes PAMP in der empfohlenen Konzentration.</li>
	<li>Kultur und Herausforderung Medium auf 37 ° C im Wasserbad erwärmen und etwa 70 mL sterile Phosphat gepufferte Kochsalzlösung (PBS, pH 7,2) bei Zimmertemperatur aufbewahren.</li>
	<li>Hinzugeben Sie 10 mL Kulturmedium mit 10 mL-Pipette und Pipette Hilfen für eine 50 mL-Tube und Platz auf dem Eis.</li>
	<li>Fügen Sie etwa 30 mL 70 % igem Ethanol zu einem 100 mL Becherglas und Ort endet sezieren Scheren und Pinzetten in das Becherglas, mikrobielle Kontamination zu verhindern.</li>
	<li>Bereiten Sie Lyse Puffer RNA Isolierung durch Zugabe von 10 µL β-Mercaptoethanol (unter einem Abzug vor) zu jeder 1 mL Puffer RLT in ein 50 mL-Tube. Machen Sie nur die Menge, die benötigten (600 µL pro Probe) werden ca. 1 x 106 Zellen bestehend. Hinweis: Der Puffer RLT ist ein Bestandteil der RNA-Extraktion-Kit, das die Bindung der RNA der Kieselsäure Membran unterstützt.</li>
</ol>3. Splenocyte Isolation und Herausforderung
<ol><li>Einschläfern Sie Mäuse zu einem bestimmten Zeitgeber Zeitpunkt über Narkose halten sie in ihrem ursprünglichen Käfig und den Käfig mit einer Durchflussrate von 3 L/min. weiter liefert CO2 für 1 min nach Atmung stoppt CO2 hinzufügen.</li>
	<li>Tod durch zervikale Dislokation zu bestätigen, indem Sie Daumen und Zeigefinger auf beiden Seiten des Halses an der Basis des Schädels. Oder drücken Sie einer Rute an der Basis des Schädels und schnell ziehen (mit der anderen Hand) die Basis für das Heck oder der hinteren Gliedmaßen, Trennung der Halswirbel vom Schädel22zu verursachen.</li>
	<li>Sprühen Sie den Maus-Stamm mit 70 % Ethanol und mit einem Papiertuch abwischen. Platzieren Sie den Mauszeiger auf seinen Rücken und schräg auf der rechten Seite. Schneiden Sie das Fell, Schere mit sezieren, entlang der Maus links über auf halbem Weg zwischen der Vorder- und Hinterbeine.</li>
	<li>Mit Pinzette, schnappen Sie sich das Bauchfell und einen Einschnitt nicht zu beschädigen die Milz aufmerksam machen. Milz mit einer Pinzette entfernen und in eine sterile 50 mL Röhrchen mit etwa 10 mL der Nährmedien auf Eis legen. Wiederholen Sie für die restlichen Tiere. Hinweis: Die Milz ist die Farbe der Kidney-Bohnen, und er ist länger und flacher als der Niere.</li>
	<li>
Übertragen Sie eine Milz mit 2 mL Kulturmedium auf eine kleine sterile Petrischale.
	<ol>
<li>Die Milz durch Schleifen zwischen den mattierten Teil zwei sterile mattierte Folien zu homogenisieren. Halten Sie wenn möglich die Ausgabe und die Zellen im Medium bei der Homogenisierung.</li>
		<li>Einmal gründlich homogenisiert, pipettieren der 2 mL Kulturmedium mit der splenocyten durch ein 40 µm Nylon Zelle Sieb in ein 50 mL-Tube.</li>
		<li>Wiederholen Sie die obigen Schritte für die verbleibenden Milz mit neuen Paare mattierte Folien, 50 mL Röhrchen mit Nährmedium und Zelle Siebe.</li>
	</ol>
</li>
	<li>Hinzugeben Sie 8 mL kalte Kulturmedium zu jedem der 50 mL Röhrchen mit splenocyten für ein Gesamtvolumen von 10 mL/Tube. Bestimmen Sie die Anzahl der Zellen pro Milliliter mit einem Hemocytometer.</li>
	<li>Fügen Sie hinzu, ca. 1 x 106 Zellen/Well Kultur 6-Well-Platten. Anzahl der Bohrungen, die entsprechen der Anzahl der verschiedenen PAMPs für das Experiment verwendet wird und ein Steuerelement fügen Sie auch Zellen hinzu. Fügen Sie 3 mL Kulturmedium oder 3 mL Herausforderung Medium in die jeweiligen Vertiefungen.</li>
	<li>Inkubieren Sie die Platten bei 37 ° C in 5 % CO2 für 3 h.</li>
	<li>Kratzen Sie die Zellen aus der Tiefe der nun mit einer 1.000 µL pipettieren Tipp mit einer Mikropipette P1000 verbunden. Die Zellen mit der gleichen 1.000 µL pipettieren Spitze, eine 15 mL Tube-haltigem Medium zu übertragen.</li>
	<li>Pellet-Zellen durch Zentrifugation bei 167 X g für 5 min bei Raumtemperatur. Den überstand zu entfernen und Waschen der Zelle Pellet mit 5 mL PBS.</li>
	<li>Pellet-Zellen ein zweites Mal bei 167 X g für 5 min, überstand zu entfernen und die Zelle Pellet 600 µL Lyse Puffer hinzufügen, um die Zellen lysiert. Fahren Sie dann mit RNA isoliert.</li>
</ol>(4) RNA Isolation und cDNA Synthese
<ol><li>RNA von splenocyten mit dem RNA-Extraktion-Kit nach Herstellerangaben zu isolieren und die "optionale" auf Spalte DNA Verdauung führen.</li>
	<li>Bestimmen Sie vor cDNA Synthese RNA-Konzentration mit einer Microvolume Spektralphotometer, stellen Sie sicher, dass die Konzentration im optimalen Bereich der RNA (bis zu 2 µg) die cDNA-Synthese-Kit.</li>
	<li>
Synthese cDNA für jede der Proben mit der reversen Transkription-Kit nach Herstellerangaben. Verwenden Sie 10 µL RNA für jede der Proben in eine gesamte Reaktionsvolumen von 20 µL. Fügen Sie am Ende der reversen Transkription (Thermocycler laufen) 20 μL H2O, jede Reaktion.
</li>
	<li>Der standard geschwungenen mit P10 und P20 Mikropipette mRNA von ein paar Kontrollproben (z. B. 5 µL aus 2 Proben für eine Gesamtmenge von 10 µL) in ein 0,5 mL Röhrchen zur Vorbereitung der cDNA Pool zu bauen.<ol>
<li>Fügen Sie 10 µL 2 x Reverse-Transkriptase-master-Mix.</li>
		<li>Fügen Sie bei der Fertigstellung der reversen Transkription 10 µL H2O das Reaktionsgefäß hinzu, dienen als Ausgangspunkt Konzentration ("1") wird in der Verdünnungsreihe für die Standardkurve.</li>
		<li>Führen Sie ein 10-divisibel Verdünnungsreihe (1 bis 10-4) durch Zugabe von Wasser mittels einer Mikropipette P100 oder P200 in vier 0,5 mL Röhrchen benannt 10-410-1, 10-2und 10-345 µL.<ol>
<li>Fügen Sie 5 µL der Ausgangspunkt Konzentration "1" in das erste Rohr (10-1) mit einem P20 Micropipettor, Mix von oben und unten pipettieren mehrmals, dann Transfer 5 µL aus der 10-1 Tube in die Röhre bezeichnet, 10-2 und Mix.</li>
			<li>5 µL mit einer Mikropipette P20 aus der Tube 10-2 in die Röhre bezeichnet 10-3 zu übertragen und zu mischen. 5 µL mit einem P20 Micropipettor aus der Tube 10-3 in das Rohr benannt 10-4 zu übertragen und zu mischen.</li>
		</ol>
</li>
	</ol>
</li>
</ol>5. Quantitative Polymerase-Kettenreaktion (qPCR)
<ol><li>Bestimmen Sie relative Quantifizierung der mRNA-Niveaus durch qPCR. Innerhalb der experimentellen einzurichten, wählen Sie "Quantifizierung – Relative Standardkurve" und "TaqMan" Chemie. Änderung das Reaktionsvolumen zu 10 µL. Geben Sie die relevante Informationen in das Platte-Layout (z.B.Zielgen Standardkurve, Reporter, usw.).</li>
	<li>Die Reaktion so aufzubereiten, dass es 0,5 µL den Primer/Sonden-Assay, 5 µL der Gen-Expression-master-Mix, H2O 2 µL und 2.5 enthält µL cDNA (10 – 100 ng).<ol>
<li>Bereiten Sie einen master-Mix durch Multiplikation aller vorhergehenden Reagenzien (mit Ausnahme der cDNA) durch die Anzahl der Reaktionen, achten Sie darauf, gehören diejenigen von der Standardkurve Negativkontrollen, Durchführung jeder Reaktion in Duplikat und 2 zusätzliche Reaktionen, die berücksichtigt werden pipettieren Variation.</li>
		<li>Pipettieren 7,5 µL bereit master-Mix in vorgegebenen Vertiefungen in einer Reaktion der 96-Well-Platte mit einer Mikropipette oder einer Mehrkanal-Pipette. Pipettieren 2,5 µL cDNA in den entsprechenden Brunnen für die unbekannten und Standards und 2,5 µL von H2O in die negativ-Kontrolle-Brunnen.</li>
		<li>Beinhalten Sie Primer/Sonden-Assays für die verschiedenen molekularen uhrengene und auch einen Test für eine endogene Steuerung (z. B. β-Aktin).</li>
	</ol>
</li>
	<li>Um relative Ausdruckswerte zu ermitteln, berechnen Sie die mittlere relative Menge für jede Wiederholung, dann für jede Probe, teilen Sie die mittlere relative Menge für das jeweilige Zielgen durch die mittlere relative Menge für β-Aktin.</li>
</ol>6. statistische Analyse
<ol><li>Statistische Analyse-Software verwenden, geben Sie Daten in das Programm unter der Spalte Statistik-Option. Wählen Sie eine einfache ANOVA mit der Dunnett post-hoc-Test zur Bewertung der Unterschiede zwischen den Mittelwerten der Uhr Genexpression nach PAMP Herausforderung gegenüber der Kontrolle.</li>
</ol>

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Innerhalb dieses Protokolls kann ein Microvolume Spektralphotometer zur Quantifizierung und Beurteilung der Reinheit der verwendeten bei der Bestimmung der Genexpression RNA verwendet werden. Nukleinsäuren absorbieren UV-Licht bei 260 nm, Proteine in der Regel absorbieren Licht bei 280 nm, während andere potentielle Schadstoffe verwendet, während ein RNA-Extraktionsverfahren (z. B. Phenol) nachweisbar bei 230 sind nm. Daher, durch die Beurteilung der Extinktion (A) Verhältnis bei 260/280 nm (RNA zum Protein)...

Der master-Clock bei Säugetieren, der 24 h Schwingungen für fast alle Aspekte der Physiologie und Verhalten orchestriert, liegt in den suprachiasmatischen Kern (SCN) des Hypothalamus1,2. Neben der Regulierung der biologischen Prozesse auf organismal Ebene, synchronisiert der master-Clock auch periphere zelluläre Uhren im gesamten Körper3,4,5. Während der molekularen Uhr Maschinen aus mindestens drei ineinandergreifenden transkriptionelle translationale Feedback-Schleifen besteht, besteht der Kern der Periode (Per1-3), Cryptochrome (Cry1-2), Bmal1, und Uhr Gene6,7. Neben der Pflege des genaue Timing der molekularen Uhr Kern, einige ergänzende Uhr Genprodukte (z. B. Rev-Erbα und Dbp) regulieren auch Ausdruck des nicht-uhrengene, d. h. Uhr kontrollierten Gene (KVG)6 , 7.
Funktionelle Molekulare Uhren wurden in verschiedenen immun Gewebe (z. B. Milz und Lymphknoten)8 und Zellen (z. B. B Zellen, Dendritische Zellen, Makrophagen)8,9beschrieben. Diese Zellen erkennen und reagieren auf Pathogen-assoziierte molekulare Muster (PAMPs), konservierte mikrobielle Komponenten über angeborene immune Anerkennung Rezeptoren wie Toll-Like-Rezeptoren (TLR)10. Bisher wurden 13 funktionale TLRs beschrieben, erkennen die mikrobielle Bestandteile wie bakterielle Zellwand-Komponenten, flagellar Protein und mikrobielle Nukleinsäuren10. PAMP, Lipopolysaccharid (LPS), eine Zellwand-Komponente von Gram-negativen Bakterien erkannt von TLR4, nachweislich zirkadianen Rhythmen auf organismal und molekularer Ebene zu verändern. Z. B. in Vivo Herausforderung der LPS induzierte photic-ähnliche Phase Verzögerungen Aktivität in Mäusen11 gemessen und führte zu reduzierten Uhr gen-Expression in der SCN und Leber in Situ Hybridisierung und quantitative PCR bestimmt, bzw. in Ratten12. Nach einer in-Vivo -Herausforderung mit LPS ergab die Analyse der menschlichen peripheren Blut Leukozyten13 und subkutanem Fettgewebe14 veränderte Expression von mehreren uhrengene gemessen über qPCR. Zu guter Letzt geändert ex Vivo LPS Herausforderungen des menschlichen Makrophagen und Maus peritonealen Makrophagen, führte auch zu Uhr Ausdruck qPCR14gemessen.
Hier beschreiben wir ein Protokoll, um den Einfluss der PAMPs LPS, ODN1826 (synthetische Oligonukleotide mit unmethylated CpG Motive), zu bewerten und Hitze getötet Listeria Monocytogenes (HKLM), anerkannt von TLR4, TLR9 und TLR2, bzw. auf Molekulare Uhr Genexpression in Maus splenocyten. Das Protokoll enthält Maus Splenektomie, Splenocyte Isolierung und Herausforderung, RNA Extraktion, cDNA Synthese und qPCR Ausdruck mehrere uhrengene bewerten. Dieses Protokoll ermöglicht für den rechtzeitigen Erwerb einer großen Anzahl von Immunzellen mit sehr kleinen Tier oder zellulären Manipulation, die dann ex Vivo mit verschiedenen PAMPs in Frage gestellt. Die molekulare Uhr hat gezeigt, dass verschiedene Aspekte der Immunantwort8,15,16modulieren, Störung der molekularen Uhr beeinträchtigt daher höchstwahrscheinlich die richtige zeitabhängige Variation von der Immunantwort. Darüber hinaus da Störungen des zirkadianen Rhythmen zu schweren Pathologien17,18,19,20führen können, kann es von Interesse für Forscher, splenocyten mit einer breiten Palette von Herausforderung sein Moleküle und deren Einfluss auf die Uhr zu beurteilen.

<table><tbody><tr><td>Frosted slides</td><td>Fisher</td><td>12-550-343</td><td></td></tr><tr><td>Cell strainers</td><td>Fisher</td><td>22363547</td><td></td></tr><tr><td>Lipopolysaccharide&amp;nbsp;</td><td>InvivoGen</td><td>ltrl-eklps</td><td></td></tr><tr><td>ODN1826</td><td>InvivoGen</td><td>Tlrl-1826-1</td><td></td></tr><tr><td>HKLM</td><td>InvivoGen</td><td>Tlrl-hklm</td><td></td></tr><tr><td>RPMI 1640</td><td>Gibco</td><td>11875-093</td><td></td></tr><tr><td>PBS</td><td>Gibco</td><td>20012-043</td><td></td></tr><tr><td>RNeasy Mini Kit</td><td>Qiagen</td><td>74104 or 74106</td><td></td></tr><tr><td>RNase-Free DNase Set</td><td>Qiagen</td><td>79254</td><td></td></tr><tr><td>6-well cell culture plate</td><td>Denville</td><td>T1006</td><td></td></tr><tr><td>50 mL tubes</td><td>Corning</td><td>352070</td><td></td></tr><tr><td>15 mL tubes</td><td>Corning</td><td>352097</td><td></td></tr><tr><td>High Capacity cDNA Reverse Transcription Kit</td><td>ThermoFisher</td><td>4368814</td><td></td></tr><tr><td>TaqMan Gene Expression Assays b-actin</td><td>ThermoFisher</td><td>Mm00607939_s1</td><td></td></tr><tr><td>TaqMan Gene Expression Assays Per2</td><td>ThermoFisher</td><td>Mm00478113_m1</td><td></td></tr><tr><td>TaqMan Gene Expression Assays Rev-erba</td><td>ThermoFisher</td><td>Mm00520708_m1</td><td></td></tr><tr><td>TaqMan Gene Expression Assays Bmal1</td><td>ThermoFisher</td><td>Mm00500226_m1</td><td></td></tr><tr><td>TaqMan Gene Expression Assays Dbp</td><td>ThermoFisher</td><td>Mm00497539_m1</td><td></td></tr><tr><td>qPCR machine StepOnePlus</td><td>ThermoFisher</td><td></td><td></td></tr><tr><td>TaqMan Gene Expression Master Mix</td><td>ThermoFisher</td><td>4369016</td><td></td></tr><tr><td>MicroAmp Fast 96-well reaction plate (0.1 mL)</td><td>ThermoFisher</td><td>4346907</td><td></td></tr><tr><td>Statistical Analysis Software</td><td>Prism 7.0a</td><td></td><td></td></tr></tbody></table>

the use of mouse splenocytes to assess pathogen-associated molecular pattern influence on clock gene expression

Vom Verhalten, Genexpression regulieren ZIRKADIANE Rhythmen fast alle Aspekte der Physiologie. Hier präsentieren wir Ihnen eine Methode zur Maus splenocyten mit der Pathogen-assoziierte molekulare Muster (PAMPs) Lipopolysaccharid (LPS), ODN1826 und Hitze getötet Listeria Monocytogenes hinterfragen und prüfen ihre Wirkung auf die molekularen zirkadianen Uhr. Bisher haben Studien untersuchen den Einfluss von LPS auf der molekularen Uhr mit einer Vielzahl von in Vivo und ex Vivo Ansätze aus einem Sortiment von Modellen (z. B. Maus, Ratte und Mensch) fokussiert. Dieses Protokoll beschreibt die Isolation und die Herausforderung des splenocyten sowie die Methodik zur Uhr Gen Ausdruck nach Herausforderung über quantitative PCR zu beurteilen. Dieser Ansatz lässt sich nicht nur der Einfluss der mikrobielle Komponenten auf der molekularen Uhr aber auch andere Moleküle zu bewerten, die Ausdruck der Uhr ändern kann. Dieser Ansatz könnte genutzt werden, um die molekularen Mechanismen wie PAMP-Toll-Like-Rezeptor-Interaktion beeinflusst Uhr Ausdruck auseinander zu necken.

Mäuse wurden geopfert, bei ZT13, splenocyten wurden isoliert und ex Vivo mit den PAMPs LPS, ODN1826 oder HKLM in Frage gestellt. Nach 3 h RNA wurde isoliert und qPCR wurde verwendet, um relative Ausdruck Niveaus der molekularen uhrengene zu beurteilen, die Uhr, Per2, Dbp, und Rev-Erbα im Vergleich zu unangefochten Kontrollzellen. Nach PAMP Herausforderung waren Uhr Ausdruck Niveaus nicht wesentlich anders als Ausdruck in der Kontroll...

Watch this Scientific Journal Video about The Use of Mouse Splenocytes to Assess Pathogen-associated Molecular Pattern Influence on Clock Gene Expression at JoVE.com

The Use of Mouse Splenocytes to Assess Pathogen-associated Molecular Pattern Influence on Clock Gene Expression

Dieses Protokoll beschreibt eine Technik, mit der Maus splenocyten, um Pathogen-assoziierte molekulare Muster zu entdecken, die molekulare Uhr Genexpression verändern.

Die Nutzung von Maus Splenocyten, Pathogen-assoziierte molekulare Muster Einfluss auf die Genexpression Uhr abzuschätzen

From behavior to gene expression, circadian rhythms regulate nearly all aspects of physiology. Here, we present a methodology to challenge mouse ...

the-use-mouse-splenocytes-to-assess-pathogen-associated-molecular

Research

JoVE Journal

Genetics

7.4K Aufrufe.  University of Hartford. Dieses Protokoll beschreibt eine Technik, mit der Maus splenocyten, um Pathogen-assoziierte molekulare Muster zu entdecken, die molekulare Uhr Genexpression verändern.

Serie: The Use of Mouse Splenocytes to Assess Pathogen-associated Molecular Pattern Influence on Clock Gene Expression

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures

Circadian clocks are functional in all light-sensitive organisms, allowing for an adaptation to the external world by anticipating daily environmental changes. Considerable progress in our understanding of the tight connection between the circadian clock and most aspects of physiology has been made in the field over the last decade. However, unraveling the molecular basis that underlies the function of the circadian oscillator in humans stays of highest technical challenge. Here, we provide a detailed description of an experimental approach for long-term (2-5 days) bioluminescence recording and outflow medium collection in cultured human primary cells. For this purpose, we have transduced primary cells with a lentiviral luciferase reporter that is under control of a core clock gene promoter, which allows for the parallel assessment of hormone secretion and circadian bioluminescence. Furthermore, we describe the conditions for disrupting the circadian clock in primary human cells by transfecting siRNA targeting CLOCK. Our results on the circadian regulation of insulin secretion by human pancreatic islets, and myokine secretion by human skeletal muscle cells, are presented here to illustrate the application of this methodology. These settings can be used to study the molecular makeup of human peripheral clocks and to analyze their functional impact on primary cells under physiological or pathophysiological conditions.

Here, we describe settings to monitor in parallel circadian bioluminescence and the secretory activity of human islet cells and primary myotubes. For this, we employed lentiviral gene delivery of a luciferase core clock reporter, followed by in vitro synchronization and collection of outflow medium by continuous cell perifusion.

Parallel Messung von Circadian Clock Genexpression und Hormon-Sekretion in primären humanen Zellkulturen

Circadian clocks are functional in all light-sensitive organisms, allowing for an adaptation to the external world by anticipating daily environmental ...

Forschung

Genetik

In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells

The circadian rhythm is a fundamental physiological process present in all organisms that regulates biological processes ranging from gene expression to sleep behavior. In vertebrates, circadian rhythm is controlled by a molecular oscillator that functions in both the suprachiasmatic nucleus (SCN; central pacemaker) and individual cells comprising most peripheral tissues. More importantly, disruption of circadian rhythm by exposure to light-at-night, environmental stressors and/or toxicants is associated with increased risk of chronic diseases and aging. The ability to identify agents that can disrupt central and/or peripheral biological clocks, and agents that can prevent or mitigate the effects of circadian disruption, has significant implications for prevention of chronic diseases. Although rodent models can be used to identify exposures and agents that induce or prevent/mitigate circadian disruption, these experiments require large numbers of animals. In vivo studies also require significant resources and infrastructure, and require researchers to work all night. Thus, there is an urgent need for a cell-type appropriate in vitro system to screen for environmental circadian disruptors and enhancers in cell types from different organs and disease states. We constructed a vector that drives transcription of the destabilized luciferase in eukaryotic cells under the control of the human PERIOD 2 gene promoter. This circadian reporter construct was stably transfected into human mammary epithelial cells, and circadian responsive reporter cells were selected to develop the in vitro bioluminescence assay. Here, we present a detailed protocol to establish and validate the assay. We further provide details for proof of concept experiments demonstrating the ability of our in vitro assay to recapitulate the in vivo effects of various chemicals on the cellular biological clock. The results indicate that the assay can be adapted to a variety of cell types to screen for both environmental disruptors and chemopreventive enhancers of circadian clocks.

In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells

An in vitro bioluminescence assay to determine cellular circadian rhythm in mammary epithelial cells is presented. This method utilizes mammalian cell reporter plasmids expressing destabilized luciferase under the control of the PERIOD 2 gene promoter. It can be adapted to other cell types to evaluate organ-specific effects on circadian rhythm.

In-vitro- Biolumineszenz-Assay zirkadianen Rhythmus in Mamma Epithelzellen zu charakterisieren

The circadian rhythm is a fundamental physiological process present in all organisms that regulates biological processes ranging from gene expression to ...

Temporal Ordering of Dynamic Expression Data from Detailed Spatial Expression Maps

During somitogenesis, pairs of epithelial somites form in a progressive manner, budding off from the anterior end of the pre-somitic mesoderm (PSM) with a strict species-specific periodicity. The periodicity of the process is regulated by a molecular oscillator, known as the "segmentation clock," acting in the PSM cells. This clock drives the oscillatory patterns of gene expression across the PSM in a posterior-anterior direction. These so-called clock genes are key components of three signaling pathways: Wnt, Notch, and fibroblast growth factor (FGF). In addition, Notch signaling is essential for synchronizing intracellular oscillations in neighboring cells. We recently gained insight into how this may be mechanistically regulated. Upon ligand activation, the Notch receptor is cleaved, releasing the intracellular domain (NICD), which moves to the nucleus and regulates gene expression. NICD is highly labile, and its phosphorylation-dependent turnover acts to restrict Notch signaling. The profile of NICD production (and degradation) in the PSM is known to be oscillatory and to resemble that of a clock gene. We recently reported that both the Notch receptor and the Delta ligand, which mediate intercellular coupling, themselves exhibit dynamic expression at both the mRNA and protein levels. In this article, we describe the sensitive detection methods and detailed image analysis tools that we used, in combination with the computational modeling that we designed, to extract and overlay expression data from distinct points in the expression cycle. This allowed us to construct a spatio-temporal picture of the dynamic expression profile for the receptor, the ligand, and the Notch target clock genes throughout an oscillation cycle. Here, we describe the protocols used to generate and culture the PSM explants, as well as the procedure to stain for the mRNA or protein. We also explain how the confocal images were subsequently analyzed and temporally ordered computationally to generate ordered sequences of clock expression snapshots, hereafter defined as "kymographs," for the visualization of the spatiotemporal expression of Delta-like1 (Dll1) and Notch1 throughout the PSM.

The segmentation clock drives oscillatory gene expression across the pre-somitic mesoderm (PSM). Dynamic Notch activity is key to this process. We use imaging and computational analyses to extract temporal dynamics from spatial expression data to demonstrate that Delta ligand and Notch receptor expression oscillate in the vertebrate PSM.

Zeitliche Reihenfolge der dynamischen Ausdruck von Daten aus Detaillierte Spatial Expression Maps

During somitogenesis, pairs of epithelial somites form in a progressive manner, budding off from the anterior end of the pre-somitic mesoderm (PSM) with a ...

Entwicklungsbiologie

Following in Real Time the Impact of Pneumococcal Virulence Factors in an Acute Mouse Pneumonia Model Using Bioluminescent Bacteria

Pneumonia is one of the major health care problems in developing and industrialized countries and is associated with considerable morbidity and mortality. Despite advances in knowledge of this illness, the availability of intensive care units (ICU), and the use of potent antimicrobial agents and effective vaccines, the mortality rates remain high1. Streptococcus pneumoniae is the leading pathogen of community-acquired pneumonia (CAP) and one of the most common causes of bacteremia in humans. This pathogen is equipped with an armamentarium of surface-exposed adhesins and virulence factors contributing to pneumonia and invasive pneumococcal disease (IPD). The assessment of the in vivo role of bacterial fitness or virulence factors is of utmost importance to unravel S. pneumoniae pathogenicity mechanisms. Murine models of pneumonia, bacteremia, and meningitis are being used to determine the impact of pneumococcal factors at different stages of the infection. Here we describe a protocol to monitor in real-time pneumococcal dissemination in mice after intranasal or intraperitoneal infections with bioluminescent bacteria. The results show the multiplication and dissemination of pneumococci in the lower respiratory tract and blood, which can be visualized and evaluated using an imaging system and the accompanying analysis software.

Streptococcus pneumoniae is the leading pathogen causing severe community-acquired pneumonia and responsible for over 2&#160;million deaths worldwide. The impact of bacterial factors implicated in fitness or virulence can be monitored in real-time in an acute mouse pneumonia or bacteremia model using bioluminescent bacteria.

Nach der in Echtzeit die Auswirkungen der Pneumokokken-Virulenzfaktoren in einer akuten Lungenentzündung Maus-Modells mit Biolumineszenz-Bakterien

Pneumonia is one of the major health care problems in developing and industrialized countries and is associated with considerable morbidity and mortality. ...

Immunologie und Infektion

A Mouse Model for Pathogen-induced Chronic Inflammation at Local and Systemic Sites

Chronic inflammation is a major driver of pathological tissue damage and a unifying characteristic of many chronic diseases in humans including neoplastic, autoimmune, and chronic inflammatory diseases. Emerging evidence implicates pathogen-induced chronic inflammation in the development and progression of chronic diseases with a wide variety of clinical manifestations. Due to the complex and multifactorial etiology of chronic disease, designing experiments for proof of causality and the establishment of mechanistic links is nearly impossible in humans. An advantage of using animal models is that both genetic and environmental factors that may influence the course of a particular disease can be controlled. Thus, designing relevant animal models of infection represents a key step in identifying host and pathogen specific mechanisms that contribute to chronic inflammation.
Here we describe a mouse model of pathogen-induced chronic inflammation at local and systemic sites following infection with the oral pathogen Porphyromonas gingivalis, a bacterium closely associated with human periodontal disease. Oral infection of specific-pathogen free mice induces a local inflammatory response resulting in destruction of tooth supporting alveolar bone, a hallmark of periodontal disease. In an established mouse model of atherosclerosis, infection with P. gingivalis accelerates inflammatory plaque deposition within the aortic sinus and innominate artery, accompanied by activation of the vascular endothelium, an increased immune cell infiltrate, and elevated expression of inflammatory mediators within lesions. We detail methodologies for the assessment of inflammation at local and systemic sites. The use of transgenic mice and defined bacterial mutants makes this model particularly suitable for identifying both host and microbial factors involved in the initiation, progression, and outcome of disease. Additionally, the model can be used to screen for novel therapeutic strategies, including vaccination and pharmacological intervention.

Animal models have proven to be invaluable tools in defining host and pathogen specific mechanisms that contribute to the development of chronic inflammation. Here we describe a mouse model of oral infection with the human pathogen Porphyromonas gingivalis and detail methodologies to assess the progression of inflammation at local and systemic sites.

Einem Mausmodell für Pathogen-induzierten chronischen Entzündung an lokalen und systemischen Seiten

Chronic inflammation is a major driver of pathological tissue damage and a unifying characteristic of many chronic diseases in humans including ...

Multiplex Cytokine Profiling of Stimulated Mouse Splenocytes Using a Cytometric Bead-based Immunoassay Platform

Bead-based immunoassays employ the same basic principle as sandwich immunoassays. Capture beads, which can be differentiated by size and internal allophycocyanin (APC) fluorescence intensity, are conjugated to antibodies specific to a particular analyte. Next, a selected panel of defined capture bead sets is incubated with a biological sample containing target analytes specific to the capture antibodies. A biotinylated detection antibody cocktail is added, which leads to the formation of capture bead-analyte-detection antibody sandwiches.
Finally, streptavidin-phycoerythrin (SA-PE) is added, which binds to biotinylated detection antibodies, providing fluorescent signal intensities in proportion to the amount of bound analyte. The PE fluorescent signal of analyte-specific beads regions is quantified using flow cytometry, and the concentrations of particular analytes are determined using data analysis software and the standard curve generated in the assay.
In this experiment, we use a mouse T helper cytokine panel to simultaneously quantify the concentration of 13 separate cytokine targets in tissue culture supernatants collected from mouse splenocytes cultured under various stimulatory conditions.

This protocol describes the quantification of multiple cytokine targets simultaneously in tissue culture supernatants collected from stimulated mouse splenocytes using multiplex bead based immunoassay platform and a flow cytometer.

Multiplex-Zytokin Profilierung der stimulierten Maus Splenocyten mit Hilfe einer durchflusszytometrischen Bead-basierte Immunoassay-Plattform

Bead-based immunoassays employ the same basic principle as sandwich immunoassays. Capture beads, which can be differentiated by size and internal ...

Using a Bacterial Pathogen to Probe for Cellular and Organismic-level Host Responses

There are a variety of strategies bacterial pathogens employ to survive and proliferate once inside the eukaryotic cell. The so-called 'cytosolic' pathogens (Listeria monocytogenes, Shigella flexneri, Burkholderia pseudomallei, Francisella tularensis, and Rickettsia spp.) gain access to the infected cell cytosol by physically and enzymatically degrading the primary vacuolar membrane. Once in the cytosol, these pathogens both proliferate as well as generate sufficient mechanical forces to penetrate the plasma membrane of the host cell in order to infect new cells. Here, we show how this terminal step of the cellular infection cycle of L. monocytogenes (Lm) can be quantified by both colony-forming unit assays and flow cytometry and give examples of how both pathogen- and host-encoded factors impact this process. We also show a close correspondence of Lm infection dynamics of cultured cells infected in vitro and those of hepatic cells derived from mice infected in vivo. These function-based assays are relatively simple and can be readily scaled up for discovery-based high-throughput screens for modulators of eukaryotic cell function.

We describe both in vitro and in vivo infection assays that can be used to analyze the activities of host-encoding factors.

Verwenden eine bakterielle Erreger, Sonde für zelluläre und organismische Ebene Host Antworten

There are a variety of strategies bacterial pathogens employ to survive and proliferate once inside the eukaryotic cell. The so-called 'cytosolic' ...

In Vivo Monitoring of Circadian Clock Gene Expression in the Mouse Suprachiasmatic Nucleus Using Fluorescence Reporters

This technique combines optical fiber mediated fluorescence recordings with the precise delivery of recombinant adeno-associated virus based gene reporters. This new and easy to use in vivo fluorescence monitoring system was developed to record the transcriptional rhythm of the clock gene, Cry1, in the suprachiasmatic nucleus (SCN) of freely moving mice. To do so, a Cry1 transcription fluorescence reporter was designed and packaged into Adeno-associated virus. Purified, concentrated virus was injected into the mouse SCN followed by the insertion of an optic fiber, which was then fixed onto the surface of the brain. The animals were returned to their home cages and allowed a 1-month post-operative recovery period to ensure sufficient reporter expression. Fluorescence was then recorded in freely moving mice via an in vivo monitoring system that was constructed at our institution. For the in vivo recording system, a 488 nm laser was coupled with a 1 &#215; 4 beam-splitter that divided the light into four laser excitation outputs of equal power. This setup enabled us to record from four animals simultaneously. Each of the emitted fluorescence signals was collected via a photomultiplier tube and a data acquisition card. In contrast to the previous bioluminescence in vivo circadian clock recording technique, this fluorescence in vivo recording system allowed the recording of circadian clock gene expression during the light cycle.

In Vivo Monitoring of Circadian Clock Gene Expression in the Mouse Suprachiasmatic Nucleus Using Fluorescence Reporters

This newly developed fluorescence-based technology enables long-term monitoring of the transcription of circadian clock genes in the suprachiasmatic nucleus (SCN) of freely moving mice in real-time and at a high temporal resolution.

In Vivo Überwachung der circadianen Uhr Genexpression in der Maus Suprachiasmatischen Kern mit Fluoreszenz-Reporter

This technique combines optical fiber mediated fluorescence recordings with the precise delivery of recombinant adeno-associated virus based gene ...

Neurowissenschaften

Imaging of In Situ Interferon Gamma Production in the Mouse Spleen following Listeria monocytogenes Infection

Cytokines are small proteins secreted by cells, mediating cell-cell communications that are crucial for effective immune responses. One characteristic of cytokines is their pleiotropism, as they are produced by and can affect a multitude of cell types. As such, it is important to understand not only which cells are producing cytokines, but also in which environment they do so, in order to define more specific therapeutics. Here, we describe a method to visualize cytokine production in situ following bacterial infection. This technique relies on imaging cytokine-producing cells in their native environment by confocal microscopy. To do so, tissue sections are stained for markers of multiple cell types together with a cytokine stain. Key to this method, cytokine secretion is blocked directly in vivo before harvesting the tissue of interest, allowing for detection of the cytokine that accumulated inside the producing cells. The advantages of this method are multiple. First, the microenvironment in which cytokines are produced is preserved, which could ultimately inform on the signals required for cytokine production and the cells affected by those cytokines. In addition, this method gives an indication of the location of the cytokine production in vivo, as it does not rely on artificial in vitro re-stimulation of the producing cells. However, it is not possible to simultaneously analyze cytokine downstream signaling in cells that receive the cytokine. Similarly, the cytokine signals observed correspond&#160;only to the time-window during which cytokine secretion was blocked. While we describe the visualization of the cytokine Interferon (IFN) gamma in the spleen following mouse infection by the intracellular bacteria Listeria monocytogenes, this method could potentially be adapted to the visualization of any cytokine in most organs.

Imaging of In Situ Interferon Gamma Production in the Mouse Spleen following Listeria monocytogenes Infection

Here, we describe a simple confocal imaging method to visualize the in situ localization of cells secreting the cytokine Interferon gamma in murine secondary lymphoid organs. This protocol can be extended for the visualization of other cytokines in diverse tissues.

Bildgebung der In Situ Interferon Gamma Produktion in der Maus Milz nach Listeria monocytogenes Infektion

Cytokines are small proteins secreted by cells, mediating cell-cell communications that are crucial for effective immune responses. One characteristic of ...

Monitoring Cell-autonomous Circadian Clock Rhythms of Gene Expression Using Luciferase Bioluminescence Reporters

In mammals, many aspects of behavior and physiology such as sleep-wake cycles and liver metabolism are regulated by endogenous circadian clocks (reviewed1,2). The circadian time-keeping system is a hierarchical multi-oscillator network, with the central clock located in the suprachiasmatic nucleus (SCN) synchronizing and coordinating extra-SCN and peripheral clocks elsewhere1,2. Individual cells are the functional units for generation and maintenance of circadian rhythms3,4, and these oscillators of different tissue types in the organism share a remarkably similar biochemical negative feedback mechanism. However, due to interactions at the neuronal network level in the SCN and through rhythmic, systemic cues at the organismal level, circadian rhythms at the organismal level are not necessarily cell-autonomous5-7. Compared to traditional studies of locomotor activity in vivo and SCN explants ex vivo, cell-based in vitro assays allow for discovery of cell-autonomous circadian defects5,8. Strategically, cell-based models are more experimentally tractable for phenotypic characterization and rapid discovery of basic clock mechanisms5,8-13.
Because circadian rhythms are dynamic, longitudinal measurements with high temporal resolution are needed to assess clock function. In recent years, real-time bioluminescence recording using firefly luciferase as a reporter has become a common technique for studying circadian rhythms in mammals14,15, as it allows for examination of the persistence and dynamics of molecular rhythms. To monitor cell-autonomous circadian rhythms of gene expression, luciferase reporters can be introduced into cells via transient transfection13,16,17 or stable transduction5,10,18,19. Here we describe a stable transduction protocol using lentivirus-mediated gene delivery. The lentiviral vector system is superior to traditional methods such as transient transfection and germline transmission because of its efficiency and versatility: it permits efficient delivery and stable integration into the host genome of both dividing and non-dividing cells20. Once a reporter cell line is established, the dynamics of clock function can be examined through bioluminescence recording. We first describe the generation of P(Per2)-dLuc reporter lines, and then present data from this and other circadian reporters. In these assays, 3T3 mouse fibroblasts and U2OS human osteosarcoma cells are used as cellular models. We also discuss various ways of using these clock models in circadian studies. Methods described here can be applied to a great variety of cell types to study the cellular and molecular basis of circadian clocks, and may prove useful in tackling problems in other biological systems.

Circadian clocks function within individual cells, i.e., they are cell-autonomous. Here, we describe methods for generating cell-autonomous clock models using non-invasive, luciferase-based real-time bioluminescence technology. Reporter cells provide tractable, functional model systems for studying circadian biology.