Die Autoren danken den Core Facility der Institute der zellulären und Organismische Biologie, Academia Sinica, für technischen Support. Diese Studie wurde unterstützt durch das Ministerium für Wissenschaft und Technologie, Taiwan (die meisten 103-2320-B-001-016-MY3, Y.-F. L.), das Programm für Translationale Innovation der biopharmazeutischen Entwicklung – Technologie unterstützt Plattform Achse Schema (NP7, Y. v.l.), und Academia Sinica (, Y.-v.l.).

1. Messung der Luciferase Reporter Signale, die γ-Sekretase Spaltung des APP-C99 oder NΔE entsprechen
Hinweis: Lesen Sie bitte den vorherigen Veröffentlichungen für detaillierte Beschreibungen der Generation von CG und NG Zellen20,21.
<ol><li>
Seed NG oder CG Zellen (20, 000 Zellen/Brunnen) auf 96-Well-Mikrotiterplatten zu einem Endvolumen von 200 μl/Well im Wachstumsmedium, der Dulbeccos geändert Eagle Medium (DMEM) zuzüglich 10 % fötalen Rinderserum (FBS), 5 μg/mL Blasticidin 250 μg/mL Antibiotikum (z.B. zusammensetzt, Zeocin), und 200 μg/mL Hygromycin B.
	<ol>
<li>Anzahl Zellen mit einem Hemocytometer.</li>
		<li>Die Mikrotiterplatten auf eine befeuchtete CO2 Inkubator übertragen und über Nacht bei 37 ° C inkubieren.</li>
	</ol>
</li>
	<li>Jedes gut entnehmen Sie 100 μL des Kulturmediums.</li>
	<li>Hinzufügen von 100 μl/Well des Wachstums mittlere mit 2 μg/mL Tetracyclin mit entweder 0,2 % Dimethyl Sulfoxid (DMSO), 2 μM CL-387.785, 2 μM N-[N-(3,5-difluorophenacetyl-L-alanyl)]-S-phenylglycine t-Butylester (DAPT), oder eine andere relevante ErbB1/ErbB2-Inhibitoren.</li>
	<li>Inkubieren Sie behandelte CG oder NG Zellen in Mikrotiterplatten bei 37 ° C für 24 h.</li>
	<li>Entfernen Sie 150 μl/Well Wachstumsmedium von Mikrotiterplatten.</li>
	<li>Fügen Sie 50 μL/Well Luciferase Assay Reagenz (siehe Tabelle der Materialien).</li>
	<li>
Die Mikrotiterplatten Lumineszenz Mikrotestplatte Leser zu übertragen.
	<ol>
<li>Pflegen Sie die Mikrotiterplatten bei Raumtemperatur für 5 min mit sanften Agitation.</li>
	</ol>
</li>
	<li>
Bestimmen der Firefly Luciferase (FL)-emittierten Lumineszenz mit einem vordefinierten Programm im Lumineszenz Mikrotestplatte Leser gespeichert.
	<ol>
<li>Öffnen Sie die Instrument-Steuerungs-Software (siehe Tabelle der Materialien für Instrument Details).</li>
		<li>Wählen Sie aus dem Menü "Werkzeug" "Luminometry".<ol>
<li>Wählen Sie unter "Einstellungen" "Ohne Filter" für Emission Filter, Tick 'Normal' für Emission Blende, geben Sie '1' für zählen Zeit und klicken Sie auf "OK" zum Einrichten der Lumineszenz-Lesung.</li>
		</ol>
</li>
		<li>Auf der Registerkarte "Gerätesteuerung" führen Sie einen Bildlauf durch die Liste der aktiven Protokolle, und wählen Sie das zuvor gespeicherte Protokoll für das Lesen von Lumineszenz.</li>
		<li>Auf der Registerkarte "Live-Anzeige" definieren Sie die Waage aus dem Pull-Down-Liste, und wählen Sie "Logarithmus" oder "Linear" für den Typ.</li>
		<li>Wählen Sie auf der Registerkarte "Temperatur" 'Off' für Platte Heizung.</li>
		<li>Klicken Sie auf "Start", um die Lumineszenz lesen durchzuführen.</li>
		<li>Bei Bedarf exportieren Sie Ergebnisse in einem Spreadsheet-Format mit dem "Explorer" in die Software eingebettet.</li>
	</ol>
</li>
</ol>2. Quantifizierung der γ-Sekretase Aktivität
<ol><li>
Definieren Sie ein CG emittierten Lumineszenz-Signal oder NG Zellen mit 0,1 % DMSO im Wachstumsmedium mit 1 μg/mL Tetracyclin als 100 % relative γ-Sekretase Aktivität allein behandelt.
	<ol>
<li>Schätzen Sie Hintergrund Lumineszenz von CG oder NG Zellen durch die Behandlung der Zellen mit Wachstumsmedium, die keine Tetracyclin enthält.</li>
	</ol>
</li>
	<li>Normalisieren Luciferase Signale von CG oder NG Zellen, die mit 1 μg/mL Tetracyclin-haltigem Wachstumsmedium kultiviert werden und entweder 1 μM CL-387.785 oder 1 μM von DAPT mit dem Luciferase-Signal ausgesendet von DMSO behandelt CG oder NG Zellen (100 % relative γ-Sekretase Tätigkeit als 2.1 definiert).</li>
</ol>

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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=Substrate-targeting+gamma-secretase+modulators.">Substrate-targeting gamma-secretase modulators.</a> Nature. 453 (7197), 925-929 (2008).</li><li>Kounnas, M. Z., 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=Modulation+of+gamma-secretase+reduces+beta-amyloid+deposition+in+a+transgenic+mouse+model+of+Alzheimer's+disease.">Modulation of gamma-secretase reduces beta-amyloid deposition in a transgenic mouse model of Alzheimer's disease.</a> Neuron. 67 (5), 769-780 (2010).</li><li>Thathiah, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+orphan+G+protein-coupled+receptor+3+modulates+amyloid-beta+peptide+generation+in+neurons.">The orphan G protein-coupled receptor 3 modulates amyloid-beta peptide generation in neurons.</a> Science. 323 (5916), 946-951 (2009).</li><li>Flajolet, 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=Regulation+of+Alzheimer's+disease+amyloid-beta+formation+by+casein+kinase+I.">Regulation of Alzheimer's disease amyloid-beta formation by casein kinase I.</a> Proc Natl Acad Sci U S A. 104 (10), 4159-4164 (2007).</li><li>Eisele, Y. S., 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=Gleevec+increases+levels+of+the+amyloid+precursor+protein+intracellular+domain+and+of+the+amyloid-beta+degrading+enzyme+neprilysin.">Gleevec increases levels of the amyloid precursor protein intracellular domain and of the amyloid-beta degrading enzyme neprilysin.</a> Mol Biol Cell. 18 (9), 3591-3600 (2007).</li><li>He, G., 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=Gamma-secretase+activating+protein+is+a+therapeutic+target+for+Alzheimer's+disease.">Gamma-secretase activating protein is a therapeutic target for Alzheimer's disease.</a> Nature. 467 (7311), 95-98 (2010).</li><li>Haapasalo, A., Kovacs, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+many+substrates+of+presenilin/gamma-secretase.">The many substrates of presenilin/gamma-secretase.</a> J Alzheimers Dis. 25 (1), 3-28 (2011).</li><li>Gillman, K. 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=Discovery+and+Evaluation+of+BMS-708163,+a+Potent,+Selective+and+Orally+Bioavailable+gamma-Secretase+Inhibitor.">Discovery and Evaluation of BMS-708163, a Potent, Selective and Orally Bioavailable gamma-Secretase Inhibitor.</a> ACS Med Chem Lett. 1 (3), 120-124 (2010).</li><li>Hopkins, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ACS+chemical+neuroscience+molecule+spotlight+on+Begacestat+(GSI-953).">ACS chemical neuroscience molecule spotlight on Begacestat (GSI-953).</a> ACS Chem Neurosci. 3 (1), 3-4 (2012).</li><li>Yang, T., Arslanova, D., Gu, Y., Augelli-Szafran, C., Xia, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantification+of+gamma-secretase+modulation+differentiates+inhibitor+compound+selectivity+between+two+substrates+Notch+and+amyloid+precursor+protein.">Quantification of gamma-secretase modulation differentiates inhibitor compound selectivity between two substrates Notch and amyloid precursor protein.</a> Mol Brain. 1, 15 (2008).</li><li>McKee, T. D., Loureiro, R. M., Dumin, J. A., Zarayskiy, V., Tate, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+cell-based+method+for+determining+the+gamma-secretase+enzyme+activity+against+both+Notch+and+APP+substrates.">An improved cell-based method for determining the gamma-secretase enzyme activity against both Notch and APP substrates.</a> J Neurosci Methods. 213 (1), 14-21 (2013).</li><li>Basi, G. S., 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=Amyloid+precursor+protein+selective+gamma-secretase+inhibitors+for+treatment+of+Alzheimer's+disease.">Amyloid precursor protein selective gamma-secretase inhibitors for treatment of Alzheimer's disease.</a> Alzheimers Res Ther. 2 (6), 36 (2010).</li><li>Liao, Y. F., Tang, Y. C., Chang, M. Y., Wang, B. J., Hu, M. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Discovery+of+small+molecular+(D)-leucinamides+as+potent,+Notch-sparing+gamma-secretase+modulators.">Discovery of small molecular (D)-leucinamides as potent, Notch-sparing gamma-secretase modulators.</a> Eur J Med Chem. 79, 143-151 (2014).</li><li>Liao, Y. F., Wang, B. J., Cheng, H. T., Kuo, L. H., Wolfe, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+necrosis+factor-alpha,+interleukin-1beta,+and+interferon-gamma+stimulate+gamma-secretase-mediated+cleavage+of+amyloid+precursor+protein+through+a+JNK-dependent+MAPK+pathway.">Tumor necrosis factor-alpha, interleukin-1beta, and interferon-gamma stimulate gamma-secretase-mediated cleavage of amyloid precursor protein through a JNK-dependent MAPK pathway.</a> J Biol Chem. 279 (47), 49523-49532 (2004).</li><li>Wang, B. 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=ErbB2+regulates+autophagic+flux+to+modulate+the+proteostasis+of+APP-CTFs+in+Alzheimer's+disease.">ErbB2 regulates autophagic flux to modulate the proteostasis of APP-CTFs in Alzheimer's disease.</a> Proc Natl Acad Sci U S A. 114 (15), E3129-E3138 (2017).</li><li>Sevigny, 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+antibody+aducanumab+reduces+Abeta+plaques+in+Alzheimer's+disease.">The antibody aducanumab reduces Abeta plaques in Alzheimer's disease.</a> Nature. 537 (7618), 50-56 (2016).</li><li>Golde, T. E., Koo, E. H., Felsenstein, K. M., Osborne, B. A., Miele, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=gamma-Secretase+inhibitors+and+modulators.">gamma-Secretase inhibitors and modulators.</a> Biochim Biophys Acta. 1828 (12), 2898-2907 (2013).</li><li>Coric, 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=Targeting+Prodromal+Alzheimer+Disease+With+Avagacestat:+A+Randomized+Clinical+Trial.">Targeting Prodromal Alzheimer Disease With Avagacestat: A Randomized Clinical Trial.</a> JAMA Neurol. 72 (11), 1324-1333 (2015).</li><li>Mitani, Y., 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=Differential+effects+between+gamma-secretase+inhibitors+and+modulators+on+cognitive+function+in+amyloid+precursor+protein-transgenic+and+nontransgenic+mice.">Differential effects between gamma-secretase inhibitors and modulators on cognitive function in amyloid precursor protein-transgenic and nontransgenic mice.</a> J Neurosci. 32 (6), 2037-2050 (2012).</li><li>Penninkilampi, R., Brothers, H. 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Die Autoren haben nichts preisgeben.

Die vielversprechenden Ergebnisse aus Phase 1 b-Studie von Aducanumab Immuntherapie für AD haben die kritische Rolle von Aβ in der Pathogenese der AD22 fest etabliert und legen nahe, dass Anti-Aβ Ansätze noch eine tragfähige Strategie für die Entwicklung von Anti-AD Drogen sind. Hier beschreiben wir zellbasierte Assays für die Quantifizierung der γ-Sekretase-katalysierte Proteolyse von APP-C99 und NΔE mit Firefly Luciferase Reporter Systemen. APP-C99 und NΔE sind die zwei am meisten gut ...

Oligomere Formen von Amyloid-β (Aβ) sind vermutlich die Hauptursache für Neurodegeneration in den Gehirnen von Patienten mit Alzheimer-Krankheit (AD)1. Aβ-Peptide werden durch die schrittweise Spaltung des Amyloid-Precursor-Protein (APP), zuerst durch β-Sekretase und dann durch γ-Sekretase2produziert. In den letzten zehn Jahren haben therapeutische Ansätze zur Behandlung der AD zur Verhinderung der Aβ Produktion3konzentriert. Die meisten Studien konzentrierten sich auf entweder die Vermehrung der α-Sekretase Aktivität, die γ-Sekretase Spaltung des APP schließt und dadurch verringern die Produktion von Aβ oder die Hemmung der β-und/oder γ-Sekretase Aktivitäten4. Leider sind nichtselektiven Hemmung β oder γ-Secretases führt zu unvermeidbaren Nebenwirkungen, die durch Störung der Tätigkeit der anderen physiologischen Substraten von β und γ-Sekretase5,6. Neuere Studien haben im Hinblick auf γ-Sekretase-Inhibitoren die Entdeckung einer Reihe von chemischen und genetischen Modulatoren berichtet, die Aβ-Produktion beim ausüben vernachlässigbarer Auswirkungen auf die wesentlichen γ-Sekretase-vermittelten Verarbeitung von Notch7 regulieren können ,8,9,10,11,12, jedoch erfolgreiche Therapie noch nicht entwickelt worden. So sind weitere systematische Bildschirme gerechtfertigt, um neuartige chemische und genetische Modifikatoren zu entdecken, die selektiv γ-Sekretase-vermittelten APP Verarbeitung modulieren kann.
Γ-Sekretase ist bekannt, mehr als 90 verschiedene Membran verankerte Proteine zu Spalten. Unter diesen Substraten ist Kerbe, deren Tätigkeit für Zelle Schicksal Entschlossenheit und Differenzierung während der Entwicklung13entscheidend. Selektiv modulierende γ-Sekretase-katalysierte APP Verarbeitung ohne wird Kerbe zu beeinträchtigen Verarbeitung wesentlich zur Minimierung Kerbe-bezogene Nebenwirkungen von γ-Sekretase-Inhibitoren, und diese Selektivität wird angenommen, dass ein primärer Faktor ist, dass die biologische Wirksamkeit von potenziellen γ-Sekretase Modulatoren für die chronische Behandlung von AD zu diktieren. Es wurden eine Reihe von Arylsulfonamide-Derivaten, wie GSI-953 (Begacestat) und BMS-708163 (Avagacestat), die gefunden wurden, potent und selektive Hemmung der γ-Sekretase14,15auszustellen. Eine frühere Studie hat gezeigt, dass die differenzielle Hemmung der γ-Sekretase Spaltung der APP und Kerbe mit einer quantitativen ELISA-basierten Test in Kombination mit in Vivo Validierung mithilfe von Zebrafisch16beobachtet werden kann. Darüber hinaus wurden zellbasierte Assays Paradigmen eingerichtet, an die potentielle Substrat Selektivität der γ-Sekretase in Richtung APP und Kerbe17,18. Unter Verwendung von Protokollen zu den beschriebenen ähnlich hierin, wir haben vor kurzem entdeckt eine neuartige Klasse von (D)-Leucinamides, die γ-Sekretase Spaltung des APP mit Notch-schonende Selektivität19potent modulieren. Diese Sammlung von Studien bilden zusammen ein Proof-of-Concept unterstützt die Vorstellung, die die Substrat Selektivität/Verfügbarkeit der γ-Sekretase chemische Modulation und experimentelle Verifikation unterworfen werden können. Dieser Assay-Plattformen setzen jedoch häufig auf relativ niedrigen Durchsatz auslesen und arbeitsintensive Ansätze, die industriellen Standards für Drug Discovery-Programme nicht erfüllen könnte.
Wir haben vor kurzem zellbasierte Luciferase Reporter-gen Assays generiert, die quantitativ, die katalytische Aktivität der γ-Sekretase gegenüber zwei unterschiedliche Substrate, die 99-amino Acid C-terminale Fragment der APP (APP-C99) und der extrazellulären bestimmen Domain gelöscht Kerbe Peptid (NΔE). APP-C99 und NΔE haben weithin als direkte Substrate der γ-Sekretase in verschiedenen Tests eingesetzt. Homogen und konsistent Luciferase Reporter-gen Assays für die γ-Sekretase Spaltung des APP-C99 oder NΔE generieren, erzielten wir ein HEK abgeleitet stabile Zelllinie (CG), die konstitutiv eine Gal4 Projektträger-gesteuerte Firefly Luciferase Reporter (ausdrückt Gal4-Luc) und Gal4/VP16-Tags APP-C99 Schmelzverfahren Protein (C99-GV). Darüber hinaus erzielten wir ein weiteres HEK abgeleitet stabile Zelllinie (NG), die konstitutiv Gal4-Luc und Gal4/VP16-markierten NΔE (NΔE-GV) ausdrückt. Mit dieser neuartigen Substrat-spezifische γ-Sekretase-Assays, bieten wir jetzt eine Methode zu quantifizieren und die katalytische Aktivität der γ-Sekretase auf unterschiedlichen Substraten (APP-C99 in CG-Zellen) oder NΔE in NG Zellen zu unterscheiden. Darüber hinaus wurden die Substrat-spezifische γ-Sekretase-Assays entwickelt, um High-Content-Screening Plattformen förderlich sein. Diese neu erzeugten γ-Sekretase-Assays könnte den Weg für die Entdeckung des neuartigen γ-Sekretase Modulatoren ebnen, die kognitive Funktion zu verbessern könnte, durch die Unterdrückung von Aβ-Produktion ohne unerwünschte Kerbe Hemmung für die Behandlung der nächsten Generation zu entlocken der AD.

<table>
	<tbody>
		<tr>
			<td>VictorLight luminescence plate reader</td>
			<td>PerkinElmer</td>
			<td>2030-0010</td>
			<td></td>
		</tr>
		<tr>
			<td>Class II, Type 2 Biological Safety Cabinet</td>
			<td>Thermo Scientific</td>
			<td>1300 Series A2</td>
			<td></td>
		</tr>
		<tr>
			<td>CL-387,785</td>
			<td>EMD Calbiochem</td>
			<td>233100-1MG</td>
			<td></td>
		</tr>
		<tr>
			<td>DAPT</td>
			<td>Merck</td>
			<td>565770</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#8217;s Modified Eagle Medium (DMEM)</td>
			<td>Thermo Fisher</td>
			<td>12100046</td>
			<td>main compnent of growth medium</td>
		</tr>
		<tr>
			<td>Fetal bovine serum (FBS)</td>
			<td>Thermo Fisher</td>
			<td>16000044</td>
			<td></td>
		</tr>
		<tr>
			<td>Blasticidin</td>
			<td>Thermo Fisher</td>
			<td>A1113903</td>
			<td></td>
		</tr>
		<tr>
			<td>Zeocin</td>
			<td>Thermo Fisher</td>
			<td>R25005</td>
			<td></td>
		</tr>
		<tr>
			<td>Hygromycin B</td>
			<td>Gibco</td>
			<td>10687010</td>
			<td></td>
		</tr>
		<tr>
			<td>Hemocytomer</td>
			<td>Sigma-Aldrich</td>
			<td>BR717805 Aldrich</td>
			<td></td>
		</tr>
		<tr>
			<td>96-well microplate</td>
			<td>Nunc</td>
			<td>156545</td>
			<td></td>
		</tr>
		<tr>
			<td>Tetracycline</td>
			<td>Sigma</td>
			<td>T7660</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxide (DMSO)</td>
			<td>Sigma</td>
			<td>D2650</td>
			<td></td>
		</tr>
		<tr>
			<td>Steady-Glo luciferase assay reagent</td>
			<td>Promega</td>
			<td>E2510</td>
			<td></td>
		</tr>
		<tr>
			<td>Humidified CO2 incubator</td>
			<td>Revco</td>
			<td>Ultima II</td>
			<td></td>
		</tr>
		<tr>
			<td>T-REx293 cell line</td>
			<td>Invitrogen</td>
			<td>R71007</td>
			<td></td>
		</tr>
		<tr>
			<td>Wallac 1420 software version 3.0</td>
			<td>PerkinElmer</td>
			<td></td>
			<td>instrument control software of the luminescence microplate reader</td>
		</tr>
	</tbody>
</table>

quantitative measurement of &#947;-secretase-mediated amyloid precursor protein and notch cleavage in cell-based luciferase reporter assay platforms

Wir haben ein paar zellbasierte Reporter-gen Assays zur Messung quantitativ γ-Sekretase Spaltung von unterschiedlichen Substraten entwickelt. Dieses Manuskript beschreibt Verfahren, die verwendet werden, um die γ-Sekretase-vermittelte Spaltung des APP-C99 oder Kerbe, mit einem Gal4 Projektträger-gesteuerte Firefly Luciferase Reporter System zu überwachen. Diese Tests wurden festgelegten stabil Co transfecting HEK293 Zellen mit Gal4-driven Luciferase Reporter-gen und entweder das Gal4/VP16-Tags C-terminale Fragment App (APP-C99; CG-Zellen), oder die Gal4/VP16-Tags Kerbe-ΔE (NΔE; NG-Zellen). Parallele Nutzung dieser Reporter-Assays, wir haben gezeigt, dass ein ErbB2-Inhibitor, CL-387.785, bevorzugt γ-Sekretase Spaltung des APP-C99 in CG Zellen, aber nicht NΔE in NG Zellen unterdrücken können. Die differenzierten Antworten, ausgestellt durch die CG und NG Zellen, wenn Sie mit CL-387.785, behandelt eine bevorzugte charakteristisch für γ-Sekretase Modulatoren, dar, die diese Antworten stehen in krassem Gegensatz zu der Pan-Hemmung der γ-Sekretase induziert durch DAPT. Unsere Studien bieten direkte Beweise dass γ-Sekretase Tätigkeiten auf verschiedenen Substraten in einem zellulären Kontext unterschieden werden können. Diese neue Assays kann daher nützliche Werkzeuge in der Drogeentdeckung für verbesserte AD-Therapien.

Hemmung der ErbB2 von CL-387.785 kann die Verarbeitung von APP-C99 von differentiell fördern Γ -Sekretase ohne Kerbe Spaltung Um eine zellbasierte Assays zu etablieren, die die proteolytische Spaltung eines bestimmten γ-Sekretase-Substrats quantitativ messen kann, erzielten wir die HEK293 abgeleitet CG-Zell-Linie durch stabile Co Transfektion von einem Tetracyclin-induzierbaren C unheilbar Gal4/VP16-Tags APP-C99 und eine Gal4 Projek...

Watch this Scientific Journal Video about Quantitative Measurement of ÃŽÂ³-Secretase-mediated Amyloid Precursor Protein and Notch Cleavage in Cell-based Luciferase Reporter Assay Platforms at JoVE.com

Quantitative Measurement of &#947;-Secretase-mediated Amyloid Precursor Protein and Notch Cleavage in Cell-based Luciferase Reporter Assay Platforms

Wir haben erfolgreich zwei Substrat-spezifische γ-Sekretase Assays generiert. Beiden zellbasierte Assays, die hier vorgestellten sollen γ-Sekretase enzymatischen Aktivitäten über den Ausgang des Firefly Luciferase Reporter zu quantifizieren.

Quantitative Messung der γ-Sekretase-vermittelten Amyloid-Precursor-Protein und Notch Spaltung in zellbasierten Luciferase Reporter Assay Plattformen

We have developed a pair of cell-based reporter gene assays to quantitatively measure &#947;-secretase cleavage of distinct substrates. This manuscript ...

quantitative-measurement-secretase-mediated-amyloid-precursor-protein

Research

JoVE Journal

Neuroscience

6.7K Aufrufe.  Academia Sinica. Wir haben erfolgreich zwei Substrat-spezifische γ-Sekretase Assays generiert. Beiden zellbasierte Assays, die hier vorgestellten sollen γ-Sekretase enzymatischen Aktivitäten über den Ausgang des Firefly Luciferase Reporter zu quantifizieren.

Serie: Quantitative Measurement of γ-Secretase-mediated Amyloid Precursor Protein and Notch Cleavage in Cell-based Luciferase Reporter Assay Platforms

Selection of Aptamers for Amyloid &beta;-Protein, the Causative Agent of Alzheimer&#39;s Disease

Alzheimer's disease (AD) is a progressive, age-dependent, neurodegenerative disorder with an insidious course that renders its presymptomatic diagnosis difficult1. Definite AD diagnosis is achieved only postmortem, thus establishing presymptomatic, early diagnosis of AD is crucial for developing and administering effective therapies2,3.
Amyloid &beta;-protein (A&beta;) is central to AD pathogenesis. Soluble, oligomeric A&beta; assemblies are believed to affect neurotoxicity underlying synaptic dysfunction and neuron loss in AD4,5. Various forms of soluble A&beta; assemblies have been described, however, their interrelationships and relevance to AD etiology and pathogenesis are complex and not well understood6. Specific molecular recognition tools may unravel the relationships amongst A&beta; assemblies and facilitate detection and characterization of these assemblies early in the disease course before symptoms emerge. Molecular recognition commonly relies on antibodies. However, an alternative class of molecular recognition tools, aptamers, offers important advantages relative to antibodies7,8. Aptamers are oligonucleotides generated by in-vitro selection: systematic evolution of ligands by exponential enrichment (SELEX)9,10. SELEX is an iterative process that, similar to Darwinian evolution, allows selection, amplification, enrichment, and perpetuation of a property, e.g., avid, specific, ligand binding (aptamers) or catalytic activity (ribozymes and DNAzymes).
Despite emergence of aptamers as tools in modern biotechnology and medicine11, they have been underutilized in the amyloid field. Few RNA or ssDNA aptamers have been selected against various forms of prion proteins (PrP)12-16. An RNA aptamer generated against recombinant bovine PrP was shown to recognize bovine PrP-&beta;17, a soluble, oligomeric, &beta;-sheet-rich conformational variant of full-length PrP that forms amyloid fibrils18. Aptamers generated using monomeric and several forms of fibrillar &beta;2-microglobulin (&beta;2m) were found to bind fibrils of certain other amyloidogenic proteins besides &beta;2m fibrils19. Ylera et al. described RNA aptamers selected against immobilized monomeric A&beta;4020. Unexpectedly, these aptamers bound fibrillar A&beta;40. Altogether, these data raise several important questions. Why did aptamers selected against monomeric proteins recognize their polymeric forms? Could aptamers against monomeric and/or oligomeric forms of amyloidogenic proteins be obtained? To address these questions, we attempted to select aptamers for covalently-stabilized oligomeric A&beta;4021 generated using photo-induced cross-linking of unmodified proteins (PICUP)22,23. Similar to previous findings17,19,20, these aptamers reacted with fibrils of A&beta; and several other amyloidogenic proteins likely recognizing a potentially common amyloid structural aptatope21. Here, we present the SELEX methodology used in production of these aptamers21.

Selection of Aptamers for Amyloid &#946;-Protein, the Causative Agent of Alzheimer's Disease

Aptamers are short ribo-/deoxyribo-oligonucleotides selected by in-vitro evolution methods based on affinity for a specific target. Aptamers are molecular recognition tools with versatile therapeutic, diagnostic, and research applications. We demonstrate methods for selection of aptamers for amyloid &beta;-protein, the causative agent of Alzheimer's disease.

Selektion von Aptameren für Amyloid β-Protein, dem Erreger der Alzheimer-Krankheit

Alzheimer's disease (AD) is a progressive, age-dependent, neurodegenerative disorder with an insidious course that renders its presymptomatic diagnosis ...

Forschung

Neurowissenschaften

Live-cell Imaging of Sensory Organ Precursor Cells in Intact Drosophila Pupae

Since the discovery of Green Fluorescent Protein (GFP), there has been a revolutionary change in the use of live-cell imaging as a tool for understanding fundamental biological mechanisms. Striking progress has been particularly evident in Drosophila, whose extensive toolkit of mutants and transgenic lines provides a convenient model to study evolutionarily-conserved developmental and cell biological mechanisms. We are interested in understanding the mechanisms that control cell fate specification in the adult peripheral nervous system (PNS) in Drosophila. Bristles that cover the head, thorax, abdomen, legs and wings of the adult fly are individual mechanosensory organs, and have been studied as a model system for understanding mechanisms of Notch-dependent cell fate decisions. Sensory organ precursor (SOP) cells of the microchaetes (or small bristles), are distributed throughout the epithelium of the pupal thorax, and are specified during the first 12 hours after the onset of pupariation. After specification, the SOP cells begin to divide, segregating the cell fate determinant Numb to one daughter cell during mitosis. Numb functions as a cell-autonomous inhibitor of the Notch signaling pathway.
Here, we show a method to follow protein dynamics in SOP cell and its progeny within the intact pupal thorax using a combination of tissue-specific Gal4 drivers and GFP-tagged fusion proteins 1,2.This technique has the advantage over fixed tissue or cultured explants because it allows us to follow the entire development of an organ from specification of the neural precursor to growth and terminal differentiation of the organ. We can therefore directly correlate changes in cell behavior to changes in terminal differentiation. Moreover, we can combine the live imaging technique with mosaic analysis with a repressible cell marker (MARCM) system to assess the dynamics of tagged proteins in mitotic SOPs under mutant or wildtype conditions. Using this technique, we and others have revealed novel insights into regulation of asymmetric cell division and the control of Notch signaling activation in SOP cells (examples include references 1-6,7 ,8).

Live-cell Imaging of Sensory Organ Precursor Cells in Intact Drosophila Pupae

In this video, we describe a method for live cell imaging of asymmetrically dividing sensory organ progenitor cells and epidermal cells in intact Drosophila pupae

Live-Cell-Imaging von Sinnesorgan Vorläuferzellen im Intact Drosophila Puppen

Since the discovery of Green Fluorescent Protein (GFP), there has been a revolutionary change in the use of live-cell imaging as a tool for understanding ...

A Galvanotaxis Assay for Analysis of Neural Precursor Cell Migration Kinetics in an Externally Applied Direct Current Electric Field

The discovery of neural stem and progenitor cells (collectively termed neural precursor cells) (NPCs) in the adult mammalian brain has led to a body of research aimed at utilizing the multipotent and proliferative properties of these cells for the development of neuroregenerative strategies. A critical step for the success of such strategies is the mobilization of NPCs toward a lesion site following exogenous transplantation or to enhance the response of the endogenous precursors that are found in the periventricular region of the CNS. Accordingly, it is essential to understand the mechanisms that promote, guide, and enhance NPC migration. Our work focuses on the utilization of direct current electric fields (dcEFs) to promote and direct NPC migration - a phenomenon known as galvanotaxis. Endogenous physiological electric fields function as critical cues for cell migration during normal development and wound repair. Pharmacological disruption of the trans-neural tube potential in axolotl embryos causes severe developmental malformations1. In the context of wound healing, the rate of repair of wounded cornea is directly correlated with the magnitude of the epithelial wound potential that arises after injury, as shown by pharmacological enhancement or disruption of this dcEF2-3. We have demonstrated that adult subependymal NPCs undergo rapid and directed cathodal migration in vitro when exposed to an externally applied dcEF. In this protocol we describe our lab's techniques for creating a simple and effective galvanotaxis assay for high-resolution, long-term observation of directed cell body translocation (migration) on a single-cell level. This assay would be suitable for investigating the mechanisms that regulate dcEF transduction into cellular motility through the use of transgenic or knockout mice, short interfering RNA, or specific receptor agonists/antagonists.

In this protocol we demonstrate how to construct custom chambers that permit the application of a direct current electric field to enable time-lapse imaging of adult brain derived neural precursor cell translocation during galvanotaxis.

A Galvanotaxis Assay für die Analyse von neuralen Vorläuferzellen Cell Migration Kinetics in einem von außen angelegten Direct Current Electric Field

The discovery of neural stem and progenitor  cells (collectively termed neural precursor cells) (NPCs) in the adult  mammalian brain has led to a body of ...

High-throughput Analysis of Mammalian Olfactory Receptors: Measurement of Receptor Activation via Luciferase Activity

Odorants create unique and overlapping patterns of olfactory receptor activation, allowing a family of approximately 1,000 murine and 400 human receptors to recognize thousands of odorants. Odorant ligands have been published for fewer than 6% of human receptors1-11. This lack of data is due in part to difficulties functionally expressing these receptors in heterologous systems. Here, we describe a method for expressing the majority of the olfactory receptor family in Hana3A cells, followed by high-throughput assessment of olfactory receptor activation using a luciferase reporter assay. This assay can be used to (1) screen panels of odorants against panels of olfactory receptors; (2) confirm odorant/receptor interaction via dose response curves; and (3) compare receptor activation levels among receptor variants. In our sample data, 328 olfactory receptors were screened against 26 odorants. Odorant/receptor pairs with varying response scores were selected and tested in dose response. These data indicate that a screen is an effective method to enrich for odorant/receptor pairs that will pass a dose response experiment, i.e. receptors that have a bona fide response to an odorant. Therefore, this high-throughput luciferase assay is an effective method to characterize olfactory receptors&#8212;an essential step toward a model of odor coding in the mammalian olfactory system.

Olfactory receptor activation patterns encode odor identity, but the lack of published data identifying odorant ligands for mammalian olfactory receptors hinders the development of a comprehensive model of odor coding. This protocol describes a method to facilitate high-throughput identification of olfactory receptor ligands and quantification of receptor activation.

Hochdurchsatz-Analyse von Säugetiergeruchsrezeptoren: Die Messung der Rezeptoraktivierung über Luciferaseaktivität

Odorants create unique and overlapping patterns of olfactory receptor activation, allowing a family of approximately 1,000 murine and 400 human receptors ...

Detection of In Situ Protein-protein Complexes at the Drosophila Larval Neuromuscular Junction Using Proximity Ligation Assay

Discs large (Dlg) is a conserved member of the membrane-associated guanylate kinase family, and serves as a major scaffolding protein at the larval neuromuscular junction (NMJ) in Drosophila. Previous studies have shown that the postsynaptic distribution of Dlg at the larval NMJ overlaps with that of Hu-li tai shao (Hts), a homologue to the mammalian adducins. In addition, Dlg and Hts are observed to form a complex with each other based on co-immunoprecipitation experiments involving whole adult fly lysates. Due to the nature of these experiments, however, it was unknown whether this complex exists specifically at the NMJ during larval development.
Proximity Ligation Assay (PLA) is a recently developed technique used mostly in cell and tissue culture that can detect protein-protein interactions in situ. In this assay, samples are incubated with primary antibodies against the two proteins of interest using standard immunohistochemical procedures. The primary antibodies are then detected with a specially designed pair of oligonucleotide-conjugated secondary antibodies, termed PLA probes, which can be used to generate a signal only when the two probes have bound in close proximity to each other. Thus, proteins that are in a complex can be visualized. Here, it is demonstrated how PLA can be used to detect in situ protein-protein interactions at the Drosophila larval NMJ. The technique is performed on larval body wall muscle preparations to show that a complex between Dlg and Hts does indeed exist at the postsynaptic region of NMJs.

Detection of In Situ Protein-protein Complexes at the Drosophila Larval Neuromuscular Junction Using Proximity Ligation Assay

This protocol demonstrates how Proximity Ligation Assay can be used to detect in situ protein-protein interactions at the Drosophila larval neuromuscular junction. With this technique, Discs large and Hu-li tai shao are shown to form a complex at the postsynaptic region, an association previously identified through co-immunoprecipitation.

Detektion<em&gt; In-situ-</em&gt; Protein-Protein-Komplexe bei der<em&gt; Drosophila</em&gt; Larven Neuromuskuläre Junction Mit Proximity Ligation Assay

Discs large (Dlg) is a conserved member of the membrane-associated guanylate kinase family, and serves as a major scaffolding protein at the larval ...

Stereotaxic Infusion of Oligomeric Amyloid-beta into the Mouse Hippocampus

Alzheimer&#8217;s disease is a neurodegenerative disease affecting the aging population. A key neuropathological feature of the disease is the over-production of amyloid-beta and the deposition of amyloid-beta plaques in brain regions of the afflicted individuals. Throughout the years scientists have generated numerous Alzheimer&#8217;s disease mouse models that attempt to replicate the amyloid-beta pathology. Unfortunately, the mouse models only selectively mimic the disease features. Neuronal death, a prominent effect in the brains of Alzheimer&#8217;s disease patients, is noticeably lacking in these mice. Hence, we and others have employed a method of directly infusing soluble oligomeric species of amyloid-beta - forms of amyloid-beta that have been proven to be most toxic to neurons - stereotaxically into the brain. In this report we utilize male C57BL/6J mice to document this surgical technique of increasing amyloid-beta levels in a select brain region. The infusion target is the dentate gyrus of the hippocampus because this brain structure, along with the basal forebrain that is connected by the cholinergic circuit, represents one of the areas of degeneration in the disease. The results of elevating amyloid-beta in the dentate gyrus via stereotaxic infusion reveal increases in neuron loss in the dentate gyrus within 1 week, while there is a concomitant increase in cell death and cholinergic neuron loss in the vertical limb of the diagonal band of Broca of the basal forebrain. These effects are observed up to 2 weeks. Our data suggests that the current amyloid-beta infusion model provides an alternative mouse model to address region specific neuron death in a short-term basis. The advantage of this model is that amyloid-beta can be elevated in a spatial and temporal manner.

Here, we present a protocol for direct stereotaxic brain infusion of amyloid-beta. This methodology provides an alternative in vivo mouse model to address the short-term effects of amyloid-beta on brain neurons.

Stereotaktische Infusion von oligomeren Amyloid-beta in die Maus-Hippocampus

Alzheimer&#8217;s disease is a neurodegenerative disease affecting the aging population. A key neuropathological feature of the disease is the ...

Quantitative Measurement of Relative Retinoic Acid Levels in E8.5 Embryos and Neurosphere Cultures Using the F9 RARE-Lacz Cell-based Reporter Assay

Retinoic acid (RA) is an important developmental morphogen that coordinates anteroposterior and dorsoventral axis patterning, somitic differentiation, neurogenesis, patterning of the hindbrain and spinal cord, and the development of multiple organ systems. Due to its chemical nature as a small amphipathic lipid, direct detection and visualization of RA histologically remains technically impossible. Currently, methods used to infer the presence and localization of RA make use of reporter systems that detect the biological activity of RA. Most established reporter systems, both transgenic mice and cell lines, make use of the highly potent RA response element (RARE) upstream of the RAR-beta gene to drive RA-inducible expression of reporter genes, such as beta-galactosidase or luciferase. The transgenic RARE-LacZ mouse is useful in visualizing spatiotemporal changes in RA signaling especially during embryonic development. However, it does not directly measure overall RA levels. As a reporter system, the F9 RARE-LacZ cell line can be used in a variety of ways, from simple detection of RA to quantitative measurements of RA levels in tissue explants. Here we describe the quantitative determination of relative RA levels generated in embryos and neurosphere cultures using the F9 RARE-LacZ reporter cell line.

Methods to accurately measure retinoic acid (RA) levels in small amounts of tissue do not exist. This protocol describes the easy, quantitative measurement of relative RA levels in E8.5 embryos and neurospheres using an RA reporter cell line.

Quantitative Messung der relativen Retinsäure Niveaus in E8.5 Embryonen und Neurosphäre Kulturen Mit der F9 RARE-Lacz Zell-basierte Reporter Assay

Retinoic acid (RA) is an important developmental morphogen that coordinates anteroposterior and dorsoventral axis patterning, somitic differentiation, ...

Assay Development for High Content Quantification of Sod1 Mutant Protein Aggregate Formation in Living Cells

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that can be caused by inherited mutations in the gene encoding copper-zinc superoxide dismutase 1 (SOD1). The structural instability of SOD1 and the detection of SOD1-positive inclusions in familial-ALS patients supports a potential causal role for misfolded and/or aggregated SOD1 in ALS pathology. In this study, we describe the development of a cell-based assay designed to quantify the dynamics of SOD1 aggregation in living cells by high content screening approaches. Using lentiviral vectors, we generated stable cell lines expressing wild-type and mutant A4V SOD1 tagged with yellow fluorescent protein and found that both proteins were expressed in the cytosol without any sign of aggregation. Interestingly, only SOD1 A4V stably expressed in HEK-293, but not in U2OS or SH-SY5Y cell lines, formed aggregates upon proteasome inhibitor treatment. We show that it is possible to quantify aggregation based on dose-response analysis of various proteasome inhibitors, and to track aggregate-formation kinetics by time-lapse microscopy. Our approach introduces the possibility of quantifying the effect of ALS mutations on the role of SOD1 in aggregate formation as well as screening for small molecules that prevent SOD1 A4V aggregation.

We describe a method to quantify the aggregation of misfolded proteins. Our protocol details lentiviral induced stable cell line generation, automated confocal imaging, and image analysis of protein aggregates. As an illustrative application, we studied the effect of small molecules in promoting SOD1 aggregation in a time- and dose-dependent manner.

Assay-Entwicklung für hohe Content Quantifizierung der Sod1 mutierten Proteins Aggregatbildung in lebenden Zellen

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that can be caused by inherited mutations in the gene encoding copper-zinc ...

Quantitative Autoradiographic Method for Determination of Regional Rates of Cerebral Protein Synthesis In Vivo

Protein synthesis is required for development and maintenance of neuronal function and is involved in adaptive changes in the nervous system. Moreover, it is thought that dysregulation of protein synthesis in the nervous system may be a core phenotype in some developmental disorders. Accurate measurement of rates of cerebral protein synthesis in animal models is important for understanding these disorders. The method that we have developed was designed to be applied to the study of awake, behaving animals. It is a quantitative autoradiographic method, so it can yield rates in all regions of the brain simultaneously. The method is based on the use of a tracer amino acid, L-[1-14C]-leucine, and a kinetic model of the behavior of L-leucine in the brain. We chose L-[1-14C]-leucine as the tracer because it does not lead to extraneous labeled metabolic products. It is either incorporated into protein or rapidly metabolized to yield 14CO2 which is diluted in a large pool of unlabeled CO2 in the brain. The method and the model also allow for the contribution of unlabeled leucine derived from tissue proteolysis to the tissue precursor pool for protein synthesis. The method has the spatial resolution to determine protein synthesis rates in cell and neuropil layers, as well as hypothalamic and cranial nerve nuclei. To obtain reliable and reproducible quantitative data, it is important to adhere to procedural details. Here we present the detailed procedures of the quantitative autoradiographic L-[1-14C]-leucine method for the determination of regional rates of protein synthesis in vivo.

Protein synthesis is&#160;a critical biological process for cells. In brain, it is required for adaptive changes. Measurement of rates of protein synthesis in the intact brain requires careful methodological considerations. Here we present the L-[1-14C]-leucine quantitative autoradiographic method for determination of regional rates of cerebral protein synthesis in vivo.

Quantitative autoradiografische Methode zur Bestimmung der regionalen Raten der zerebralen Proteinsynthese in Vivo

Protein synthesis is required for development and maintenance of neuronal function and is involved in adaptive changes in the nervous system. Moreover, it ...

In Vitro Assay for Studying the Aggregation of Tau Protein and Drug Screening

Aggregation of tau protein and formation of paired helical filaments is a hallmark of Alzheimer&#39;s disease and other tauopathies. Compared to other proteins associated with neurodegenerative diseases, the reported in vitro aggregation kinetics for tau protein are less consistent presenting a relatively high variability. Here we describe the development of an in vitro aggregation assay that mimics the expected steps associated with tau misfolding and aggregation in vivo. The assay uses the longest tau isoform (huTau441) which contains both N-terminal acidic inserts as well as four microtubule binding domains (MBD). The in vitro aggregation is triggered by addition of heparin and followed continuously by thioflavin T fluorescence in a 96 well microplate format. The tau aggregation assay is highly reproducible between different wells, experimental runs and batches of the protein. The aggregation leads to tau PHF-like morphology which is very efficient in seeding the formation of de novo fibrillar structures. In addition to its application in studying the mechanism of tau misfolding and aggregation, the current assay is a robust tool for screening drugs that could interfere with the pathogenesis of tau.

In Vitro Assay for Studying the Aggregation of Tau Protein and Drug Screening

The tau aggregation assay described in this manuscript mimics the anticipated features of in vivo tau misfolding and aggregation.

In-vitro- Test zur Untersuchung der Aggregation von Tau-Protein und Drogen-Screening

Aggregation of tau protein and formation of paired helical filaments is a hallmark of Alzheimer&#39;s disease and other tauopathies. Compared to other ...