Ringraziamo il Prof. Weiguo Zou e S. Kato per reagenti e topi e i membri del laboratorio Zou per utili discussioni. Ringraziamo anche il Laboratorio per la Stomatologia Digitalizzata e il Centro di Ricerca per le Anomalie Craniofacciali del Nono Ospedale Popolare di Shanghai per l'assistenza. Questo lavoro è stato sostenuto in parte da sovvenzioni della National Natural Science Foundation of China (NSFC) [81570950,81870740,81800949], Shanghai Summit & Plateau Disciplines, il fondo SHIPM-mu dello Shanghai Institute of Precision Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine [JC201809], il Progetto incentive del team di innovazione di alto livello per la Shanghai Jiao Tong University School of Medicine , il Fondo di ricerca interdisciplinare del nono ospedale popolare di Shanghai, Shanghai JiaoTong University School of Medicine [JYJC201902]. E L.J. è uno studioso dell'Outstanding Youth Medical Talents, del programma di sviluppo giovanile "Rising Stars of Medical Talent" di Shanghai e del progetto "Chen Xing" della Shanghai Jiaotong University.

Tutti i metodi relativi agli animali qui descritti sono stati approvati dall'Institutional Animal Care and Use Committee (IACUC) della Shanghai Jiaotong University School of Medicine.
1. Allevamento di topi di cancellazione Stat3 specifici dell'osteoclasta
NOTA: I topi Stat3fl/fl sono stati ottenuti commercialmente. I topi Ctsk-Cre sono stati forniti da S. Kato (Università di Tokyo, Tokyo, Giappone12). I topi sono stati allevati e mantenuti in specifiche condizioni esenti da agenti patogeni (SPF) nell'impianto istituzionale di origine animale in condizioni standardizzate.
<ol><li>Abbina un topo maschio sessualmente maturo a due topi femmine della stessa età. Dopo 18 giorni, controlla i controlli giornalieri per i neonati. Separare i topi femmine gravidi e tenerlo solo se necessario. Cambia topi maschi tra diverse gabbie di riproduzione se i topi femmine non erano incinte entro 1 mese dall'accoppiamento.</li>
	<li>Incrocia itopi fl/fl Stat3 con i topi Ctsk-Cre (F0). Agganciare le code per la genotipizzazione e mantenere il maschio Stat3fl/+; Topi Ctsk-Cre fino a quando non sono sessualmente maturi, che ha circa 6 settimane di età (F1). Utilizzare i seguenti primer: Stat3 F-TTGACCTGTGCTCCTACAAAAA; Stat3 R-CCCTAGATTAGGCCAGCACACA; Ctsk-cre F-GAACGCACTGATTTCGACCA; Ctsk-cre R-GCTAACCAGCGTTTTCGTTC.</li>
	<li>Croce maschio di 6 settimane Stat3fl/+; Topi Ctsk-Cre con topi Stat3fl/fl femminili. Ritagliare le code per il genotipizzazione e mantenere il maschio Stat3 fl/fl; Topi Ctsk-Cre fino a quando non sono sessualmente maturi, che ha circa 6 settimane di età (F2).</li>
	<li>Attraversa stat3 fl/fl maschio di 6 settimane; Topi Ctsk-Cre con topi Stat3fl/fl femminili (F3). Ritagliare le code per il genotipizzazione e sostituire i vecchi topi riproduttori con topi più giovani nel tempo (F3 +N).</li>
</ol>2. Raccolta campioni
<ol><li>Eutanasia sei paia di topi maschi Stat3fl/fl e Stat3Ctsk di 8 settimane separatamente con asfissia di anidride carbonica. NOTA: La portata di CO2 sposta il 30% del volume della gabbia al minuto (ad esempio, per 45 cm x 30 cm x 30 cm di gabbia la portata di CO2 è di 40 L/min).</li>
	<li>Posizionare i topi in posizione supina. Dislocare delicatamente a mano le articolazioni bilaterali dell'anca. Utilizzare forbici oftalmiche per tagliare la pelle verticalmente dalla tibia distatale e quindi sezionare l'intera pelle dall'arto posteriore.</li>
	<li>Tagliare il legamento articolare dell'articolazione destra dell'anca e dell'articolazione del ginocchio con le forbici per separare l'arto posteriore. Tagliare il trochanter e la giunzione della fibula e quindi immergere l'arto posteriore in paraformaldeide al 4%. Tenere gli arti posteriori giusti per il passaggio 3. Tagliare in modo appropriato l'osso ad entrambe le estremità per immergere completamente e fissare il midollo osseo con paraformaldeide al 4%.</li>
	<li>Tagliare il legamento articolare dell'articolazione sinistra dell'anca e dell'articolazione del ginocchio con le forbici, rimuovere delicatamente il tessuto molle e separare accuratamente la tibia e il femore. Immergere la tibia e il femore separatamente nel 75% di etanolo. Mantenere la femora per il passaggio 4 e tibiae per il passaggio 6. Assicurarsi di mantenere intatto il trochanter.</li>
</ol>3. Preparazione della sezione di paraffina
<ol><li>Fissare l'arto posteriore destro in paraformaldeide al 4% a 4 °C per 48 ore.</li>
	<li>Decalcificare: Lavare delicatamente i campioni con 1x PBS per 10 min 3 volte. Decalcificare i campioni in EDTA al 15% (150 g DI EDTA in 800 mL di ddH2O e 100 mL di 10x PBS) con un decalcificatore ad ultrasuoni per 3-4 settimane fino a quando le ossa non possono essere piegate. Sostituire con liquido decalcificante fresco a giorni diversi.</li>
	<li>Lavare delicatamente i campioni 3 volte con 1x PBS e poi immergerli in 75% di etanolo a 4 °C durante la notte.</li>
	<li>Disidratazione: Il secondo giorno, immergere sequenzialmente i campioni in etanolo al 95%, etanolo al 100% e xilene, ciascuno per 1 h due volte.</li>
	<li>Immergere i campioni in paraffina 1/2 di xilene 1/2 per 30 minuti. Immergere gli esemplari in paraffina a 65 °C durante la notte.</li>
	<li>Incorpora: selezionare un serbatoio di incorporamento adatto per l'incorporamento. Posizionare la tibia uniformemente sotto. Posizionare il femore e la tibia con un angolo di 90°. Dopo che la paraffina è stata completamente raffreddata e solidificata, rimuoverla dal serbatoio di incorporamento. Numera gli esemplari e conservali a -20 °C durante la notte.</li>
	<li>Tagliare continuamente sezioni spesse 5 μm utilizzando il microtomo. Tagliare 20-40 sezioni. Stendere le sezioni su acqua a 37 °C, aderire agli scivoli al microscopio e cuocere a 42 °C durante la notte.</li>
</ol>4. Scansione e analisi micro-CT
<ol><li>Scansiona la femora sinistra con uno scanner micro-CT. Risoluzione: 10 μm; Tensione: 70 kV; Corrente: 114 μA; Fliter: 0,5 mm Al; Fase di rotazione: 0,5°.</li>
	<li>Ricostruire immagini 3D dell'osso corticale e dell'osso trabecolare utilizzando il software di supporto dello scanner seguendo le istruzioni del produttore. Le ROM sono in una larghezza totale di 1 mm di osso trabecolare vicino alla piastra di crescita distale e in una sezione totale larga 1 mm dell'osso corticale al centro della femora.</li>
	<li>Calcolare i parametri quantitativi della microarchitettura: densità minerale ossea (BMD), frazione del volume osseo (BV/TV), spessore trabecolare (Tb.Th.), numero trabecolare (Tb.N.), separazione trabecolare (Tb.Sp.) e spessore osseo corticale (Ct.Th.).</li>
</ol>5. Colorazione TRAP
<ol><li>Cuocere le sezioni di paraffina a 65 °C per 30 minuti.</li>
	<li>Dewax: Immergere le sezioni in xilene per 10 min. Eseguire questo passaggio 3x con xilene fresco.</li>
	<li>Reidrato: Immergere le sezioni in sequenza in 100% etanolo, 95% etanolo, 70% etanolo e ddH2O, ciascuno per 5 min due volte.</li>
	<li>Preparare la soluzione di colorazione utilizzando il kit di colorazione TRAP seguendo le istruzioni del produttore e riscaldare a 37 °C. NOTA: La soluzione di colorazione TRAP deve essere preparata al momento immediatamente prima di ogni saggio.</li>
	<li>Aggiungere soluzione di colorazione da 50-100 μL a ciascun campione e incubare in una camera umida a 37 °C per 20-30 minuti. Controllare lo stato di colorazione degli osteoclasti al microscopio leggero ogni 5 minuti fino a quando non si possono vedere osteoclasti multinucleati rossi. Terminare la reazione con ddH2O.</li>
	<li>Controsostenibile in soluzione di ematossilina per 30 s. Creare un colore blu stabile per immersione in soluzione di ammoniaca all'1% per 1 minuto. Risciacquare in acqua del rubinetto che scorre lentamente.</li>
	<li>Montare le sezioni con copricapo utilizzando balsamo neutro e asciugare durante la notte.</li>
	<li>Cattura 3-5 campi di interesse al microscopio. Analizzare il perimetro trabecolare per immagine J: misurare la lunghezza della barra di scala (Ls) usando lo strumento 'linearetta ' come L1, quindi misurare la lunghezza del perimetro trabecolare usando lo strumento 'linea segmentata' come L2, la lunghezza fisica (Lp)= Ls*L2 /L1). Contare il numero di cellule positive trap con più di tre nuclei.</li>
</ol>6. Doppia etichettatura rossa calcein e alizarina
<ol><li>Preparazione del campione: Iniettare per via intraperitoneale 20 mg/kg di calceina (1 mg/mL in soluzione NaHCO3 al 2%) il giorno 0 e 25 mg/kg di alizarina rossa S (AL, 2 mg/mL in H2O) il giorno 4. Sacrifica i topi il giorno 7. Dissociare con cura le tibia e fissarlo in paraformaldeide al 4% a 4 °C per 48 ore.</li>
	<li>Disidratazione: Dopo la fissazione, lavare delicatamente la tibiae 3x con 1x PBS. Immergere sequenzialmente i campioni in etanolo al 95%, etanolo al 100% e xilene per 5 minuti due volte separatamente.</li>
	<li>Immergere i campioni in acetone per 12 ore, in 1/2 acetone 1/2 resina per 2 ore e in resina pura in un forno di essiccazione durante la notte. NOTA: La resina è stata preparata con resina disponibile in commercio (ad esempio, Embed 812 Resin) secondo le istruzioni del produttore.</li>
	<li>Incorporare: Aggiungere la resina pura in un serbatoio di incorporamento in gel di silice adatto e posizionare delicatamente i campioni per evitare bolle. Polimerizzare la resina in un forno di essiccazione a 60 °C per 48 ore.</li>
	<li>Tagliare continuamente i provini in sezioni spesse 5 μm con un microtomo rotante. Conservare il resto dei campioni con essiccante a temperatura ambiente.</li>
	<li>Aderire alle sezioni con pinzette in una goccia di alcol al 75%. Montare le sezioni con coprispasmi utilizzando balsamo neutro. Cattura l'etichettatura a fluorescenza rossa e verde con un microscopio a fluorescenza.</li>
	<li>Misurare la larghezza tra due linee di etichettatura (Ir.L.Wi), perimetro trabecolare a etichetta singola (sL.Pm), perimetro trabecolare a doppia etichetta (dL.Pm) e perimetro trabecolare totale (Tb.Pm). Calcolare il tasso di apposizione minerale (MAR) e il tasso di formazione ossea (BFR/BS). MAR = Ir.L.Wi/interval days. BFR/BS= (dL.Pm±sL.Pm/2)*MAR/Tb.Pm*100 %.</li>
</ol>

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I modelli di topi geneticamente modificati sono comunemente utilizzati per studiare il meccanismo e il trattamento farmaceutico della malattiaumana 13. I topi Ctsk-Cre sono stati ampiamente utilizzati per studi funzionali di osteoclasti6. Il presente studio ha descritto i protocolli dei metodi per analizzare il fenotipo scheletrico e studiare i geni critici che controllano l'attività osteoclasta in vivo.
L'analisi istologica è il migli...

L'osso scheletrico è il principale organo portante del corpo umano ed è sotto pressione sia dall'ambiente interno che da quello esterno durante la camminata e l'eserciziofisico 1. Per tutta la vita, le ossa passano continuamente attraverso l'autori rinnovamento, che è bilanciato da osteoblasti e osteoclasti. Il processo di sgombero di osteoclasti che cancellano vecchie ossa e osteoblasti formando nuovo osso mantiene l'omeostasi e la funzione meccanica del sistemascheletrico 2. Il disturbo dell'equilibrio può indurre malattie metaboliche ossee, come l'osteoporosi. L'osteoporosi, causata dall'eccesso di attività osteoclastica, è prevalente a livello globale e causa notevoli perdite economichealla società 2,3,4. In base al numero limitato di farmaci disponibili per il trattamento dell'osteoporosi e al loro rischio di effettiavversi 4, è importante svelare i dettagli della formazione e dell'attività dell'osteoclasta.
Gli osteoclasti derivati dal lignaggio ematopoietico monocito/macrofago hanno nuclei multipli (possono avere da 2 a 50 nuclei) e sono grandi (di solito superiori a 100 μm di diametro)2. Sebbene l'esplorazione dei meccanismi e lo screening dei farmaci per i disturbi osteoclastici siano stati ampiamente migliorati attraverso la coltura osteoclasta in vitro, le complicate reazioni organiche rendono le prove in vivo indispensabili per la terapia mirata. A causa delle somiglianze genetiche e fisiopatofiche tra topi e esseri umani, i modelli di topi geneticamente modificati sono comunemente utilizzati per studiare i meccanismi e i trattamenti farmaceutici delle malattie umane in vivo6. Il sistema Cre-loxP è una tecnologia ampiamente utilizzata per l'editing genico del topo e ha permesso ai ricercatori di indagare le funzioni geniche in modo specifico per tessuti /cellule 5. La catepsina K (CSTK) è una proteasi cisteina secreta dagli osteoclasti che può degradare il collagene osseo8. È ben accettato che il CTSK sia espresso selettivamente negli osteoclasti maturi; pertanto, i topi Ctsk-Cre sono considerati uno strumento utile per studi funzionali sugli osteoclasti ed è stato utilizzato6.
Il trasduttore di segnale e attivatore della famiglia di trascrizione (STAT) è classico e altamente significativo nella progressione e nello sviluppo dell'immunità edel cancro 7,8. Tra sette STATISTICHE, STAT3 è segnalato per essere il più rilevante per l'omeostasi ossea9,10. Diversi studi in vivo hanno riportato che l'inattivazione specifica di STAT3 negli osteoblasti diminuisce la formazioneossea 9,10. Tuttavia, le prove solide riguardanti la partecipazione di STAT3 alla formazione di osteoclasti e al metabolismo osseo in vivo sono ancora limitate. Recentemente, abbiamo fornito prove in vivo con un modello di topo di cancellazione Stat3 specifico per osteoclasta(Stat3fl/fl; Ctsk-Cre, di seguito chiamato Stat3Ctsk) che STAT3 partecipa alla differenziazione osteoclasta e al metabolismoosseo 11. Nel presente studio, descriviamo i metodi e i protocolli che abbiamo usato per analizzare i cambiamenti nella massa ossea, istomorfologia ossea e anabolismo osseo e catabolismo dei topi Stat3Ctsk al fine di studiare l'influenza della cancellazione STAT3 specifica dell'osteoclasta sull'omeostasi ossea.

<table>
	<tbody>
		<tr>
			<td>4% Paraformaldehyde solution</td>
			<td>Sangon biotech Co., Ltd.</td>
			<td>E672002</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetone</td>
			<td>Shanghai Experimental Reagent Co., Ltd.</td>
			<td>80000360</td>
			<td></td>
		</tr>
		<tr>
			<td>Alizarin</td>
			<td>Sigma-Aldrich</td>
			<td>A5533</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonia solution</td>
			<td>Shanghai Experimental Reagent Co., Ltd.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Calcein</td>
			<td>Sigma-Aldrich</td>
			<td>C0875</td>
			<td></td>
		</tr>
		<tr>
			<td>Ctsk-Cre mice</td>
			<td></td>
			<td></td>
			<td>a gift from S. Kato, University of Tokyo, Tokyo, Japan</td>
		</tr>
		<tr>
			<td>DDSA</td>
			<td>Electron Microscopy Sciences</td>
			<td>13710</td>
			<td></td>
		</tr>
		<tr>
			<td>DeCa RapidlyDecalcifier</td>
			<td>Pro-Cure</td>
			<td>DX1100</td>
			<td></td>
		</tr>
		<tr>
			<td>DMP-30</td>
			<td>Electron Microscopy Sciences</td>
			<td>13600</td>
			<td></td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Shanghai Experimental Reagent Co., Ltd.</td>
			<td>60-00-4</td>
			<td></td>
		</tr>
		<tr>
			<td>EMBED 812 RESIN</td>
			<td>Electron Microscopy Sciences</td>
			<td>14900</td>
			<td></td>
		</tr>
		<tr>
			<td>fluorescence microscope</td>
			<td>Olympus</td>
			<td>IX73</td>
			<td></td>
		</tr>
		<tr>
			<td>Hematoxylin solution</td>
			<td>Beyotime Biotechanology</td>
			<td>C0107</td>
			<td></td>
		</tr>
		<tr>
			<td>Micro-CT</td>
			<td>Scanco Medical AG</td>
			<td>&#956;CT 80</td>
			<td></td>
		</tr>
		<tr>
			<td>NaHCO3</td>
			<td>Shanghai Experimental Reagent Co., Ltd.</td>
			<td>10018918</td>
			<td></td>
		</tr>
		<tr>
			<td>Neutral balsam</td>
			<td>Sangon biotech Co., Ltd.</td>
			<td>E675007</td>
			<td></td>
		</tr>
		<tr>
			<td>NMA</td>
			<td>Electron Microscopy Sciences</td>
			<td>19000</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraffin</td>
			<td>Sangon biotech Co., Ltd.</td>
			<td>A601889</td>
			<td></td>
		</tr>
		<tr>
			<td>rotary microtome</td>
			<td>Leica</td>
			<td>RM2265</td>
			<td></td>
		</tr>
		<tr>
			<td>Stat3fl/fl mice</td>
			<td>GemPharmatech Co., Ltd</td>
			<td>D000527</td>
			<td></td>
		</tr>
		<tr>
			<td>TRAP staining kit</td>
			<td>Sigma-Aldrich</td>
			<td>387A</td>
			<td></td>
		</tr>
		<tr>
			<td>xylene</td>
			<td>Shanghai Experimental Reagent Co., Ltd.</td>
			<td>1330-20-7</td>
			<td></td>
		</tr>
	</tbody>
</table>

skeletal phenotype analysis of a conditional stat3 deletion mouse model

I modelli di topo transgenico sono potenti per comprendere i geni critici che controllano la differenziazione e l'attività dell'osteoclasta e per studiare i meccanismi e i trattamenti farmaceutici dell'osteoporosi. I topi Cathepsin K (Ctsk)-Cre sono stati ampiamente utilizzati per studi funzionali sugli osteoclasti. Il trasduttore di segnale e attivatore della trascrizione 3 (STAT3) è rilevante nell'omeostasi ossea, ma il suo ruolo negli osteoclasti in vivo rimane scarsamente definito. Per fornire la prova in vivo che STAT3 partecipa alla differenziazione dell'osteoclasta e al metabolismo osseo, abbiamo generato un modello di topo di cancellazione Stat3 specifico dell'osteoclasta(Stat3 fl/fl; Ctsk-Cre) e analizzato il suo fenotipo scheletrico. La scansione micro-CT e la ricostruzione 3D implicavano un aumento della massa ossea nei topi knockout condizionali. Colorazione H&E, colorazione doppia rossa di calceina e alizarina e colorazione della fosfatasi acida resistente al tartrato (TRAP) sono state eseguite per rilevare il metabolismo osseo. In breve, questo protocollo descrive alcuni metodi e tecniche canoniche per analizzare il fenotipo scheletrico e studiare i geni critici che controllano l'attività osteoclasta in vivo.

Utilizzando il presente protocollo, sono stati generati topi di cancellazione Stat3 specifici osteoclasti per studiare l'influenza della cancellazione di STAT3 sulla differenziazione dell'osteoclasta. I topi Stat3Ctsk e i loro compagni di cucciolata di tipo selvatico (WT) sono stati allevati e tenuti dopo il genotipizzazione. I macrofagi del midollo osseo sono stati isolati e coltivati in osteoclasti e la cancellazione di STAT3 nei topi Stat3Ctsk è stata...

Watch this Scientific Journal Video about Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model at JoVE.com

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model

Questo protocollo descrive un metodo canonico per comprendere i geni critici che controllano l'attività osteoclasta in vivo. Questo metodo utilizza un modello di topo transgenico e alcune tecniche canoniche per analizzare il fenotipo scheletrico.

Analisi del fenotipo scheletrico di un modello di mouse di eliminazione Stat3 condizionale

Transgenic mouse models are powerful for understanding the critical genes controlling osteoclast differentiation and activity, and for studying mechanisms ...

skeletal-phenotype-analysis-conditional-stat3-deletion-mouse

Research

JoVE Journal

Biology

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model

4.3K Views.  National Clinical Research center of Stomatology. Questo protocollo descrive un metodo canonico per comprendere i geni critici che controllano l'attività osteoclasta in vivo. Questo metodo utilizza un modello di topo transgenico e alcune tecniche canoniche per analizzare il fenotipo scheletrico.

Video: Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model

A Neuronal and Astrocyte Co-Culture Assay for High Content Analysis of Neurotoxicity

High Content Analysis (HCA) assays combine cells and detection reagents with automated imaging and powerful image analysis algorithms, allowing measurement of multiple cellular phenotypes within a single assay. In this study, we utilized HCA to develop a novel assay for neurotoxicity. Neurotoxicity assessment represents an important part of drug safety evaluation, as well as being a significant focus of environmental protection efforts. Additionally, neurotoxicity is also a well-accepted in vitro marker of the development of neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Recently, the application of HCA to neuronal screening has been reported. By labeling neuronal cells with &beta;III-tubulin, HCA assays can provide high-throughput, non-subjective, quantitative measurements of parameters such as neuronal number, neurite count and neurite length, all of which can indicate neurotoxic effects. However, the role of astrocytes remains unexplored in these models. Astrocytes have an integral role in the maintenance of central nervous system (CNS) homeostasis, and are associated with both neuroprotection and neurodegradation when they are activated in response to toxic substances or disease states. GFAP is an intermediate filament protein expressed predominantly in the astrocytes of the CNS. Astrocytic activation (gliosis) leads to the upregulation of GFAP, commonly accompanied by astrocyte proliferation and hypertrophy. This process of reactive gliosis has been proposed as an early marker of damage to the nervous system. The traditional method for GFAP quantitation is by immunoassay. This approach is limited by an inability to provide information on cellular localization, morphology and cell number. We determined that HCA could be used to overcome these limitations and to simultaneously measure multiple features associated with gliosis - changes in GFAP expression, astrocyte hypertrophy, and astrocyte proliferation - within a single assay. In co-culture studies, astrocytes have been shown to protect neurons against several types of toxic insult and to critically influence neuronal survival. Recent studies have suggested that the use of astrocytes in an in vitro neurotoxicity test system may prove more relevant to human CNS structure and function than neuronal cells alone. Accordingly, we have developed an HCA assay for co-culture of neurons and astrocytes, comprised of protocols and validated, target-specific detection reagents for profiling &beta;III-tubulin and glial fibrillary acidic protein (GFAP). This assay enables simultaneous analysis of neurotoxicity, neurite outgrowth, gliosis, neuronal and astrocytic morphology and neuronal and astrocytic development in a wide variety of cellular models, representing a novel, non-subjective, high-throughput assay for neurotoxicity assessment. The assay holds great potential for enhanced detection of neurotoxicity and improved productivity in neuroscience research and drug discovery.

This article describes a novel protocol and reagent set designed for sensitive measurement of neurotoxic effects of compounds and treatments on co-cultures of neurons and astrocytes using high content analysis. Results demonstrate that high content analysis represents an exciting novel technology for neurotoxicity assessment.

Un neuronale e astrociti Co-Cultura Assay per l&#39;analisi dei contenuti elevati di neurotossicità

High Content Analysis (HCA) assays combine cells and detection reagents with automated imaging and powerful image analysis algorithms, allowing ...

Ricerca

Biologia

Analysis of the Development of a Morphological Phenotype as a Function of Protein Concentration in Budding Yeast

Gene deletion and protein overexpression are common methods for studying functions of proteins. In this article, we describe a protocol for analysis of phenotype development as a function of protein concentration at population and single-cell levels in Saccharomyces cerevisiae. Although this protocol is based on the overexpression of a protein, it can easily be adapted for morphological phenotypes dependent on suppression of protein expression. Our lab is interested in studying the signaling properties of the endocytic adaptor protein epsin. To that purpose we used a dominant negative approach in which we over-expressed the conserved Epsin N-Terminal Homology (ENTH) domain in order to interfere with the functions of endogenous epsin-2 (Ent2 or YLR206W). We observed that overexpression of the ENTH domain of Ent2 (ENTH2) in wild type cells led to a cell division defect that is dependent on the mislocalization of a family of scaffolding proteins, septins.

Gene deletion and protein overexpression are common methods for studying functions of proteins. In this article, we describe a protocol for analysis of phenotype development as a function of protein concentration at population and single-cell levels in Saccharomyces cerevisiae.

Analisi dello sviluppo di un fenotipo morfologico come funzione della concentrazione di proteine ​​in lievito

Gene deletion and protein overexpression are common methods for studying functions of proteins. In this article, we describe a protocol for analysis of ...

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

Imaging in vivo e trattamenti terapeutici in un modello di mouse ortotopico di cancro ovarico

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

Analysis of Skeletal Muscle Defects in Larval Zebrafish by Birefringence and Touch-evoke Escape Response Assays

Zebrafish (Danio rerio) have become a particularly effective tool for modeling human diseases affecting skeletal muscle, including muscular dystrophies1-3, congenital myopathies4,5, and disruptions in sarcomeric assembly6,7, due to high genomic and structural conservation with mammals8. Muscular disorganization and locomotive impairment can be quickly assessed in the zebrafish over the first few days post-fertilization. Two assays to help characterize skeletal muscle defects in zebrafish are birefringence (structural) and touch-evoked escape response (behavioral).
Birefringence is a physical property in which light is rotated as it passes through ordered matter, such as the pseudo-crystalline array of muscle sarcomeres9. It is a simple, noninvasive approach to assess muscle integrity in translucent zebrafish larvae early in development. Wild-type zebrafish with highly organized skeletal muscle appear very bright amidst a dark background when visualized between two polarized light filters, whereas muscle mutants have birefringence patterns specific to the primary muscular disorder they model. Zebrafish modeling muscular dystrophies, diseases characterized by myofiber degeneration followed by repeated rounds of regeneration, exhibit degenerative dark patches in skeletal muscle under polarized light. Nondystrophic myopathies are not associated with necrosis or regenerative changes, but result in disorganized myofibers and skeletal muscle weakness. Myopathic zebrafish typically show an overall reduction in birefringence, reflecting the disorganization of sarcomeres.
The touch-evoked escape assay involves observing an embryo&#39;s swimming behavior in response to tactile stimulation10-12. In comparison to wild-type larvae, mutant larvae frequently display a weak escape contraction, followed by slow swimming or other type of impaired motion that fails to propel the larvae more than a short distance12. The advantage of these assays is that disease progression in the same fish type can be monitored in vivo for several days, and that large numbers of fish can be analyzed in a short time relative to higher vertebrates.

The zebrafish is now an established and powerful tool for modeling muscular dystrophies, congenital myopathies, and related neuromuscular diseases. Birefringence and touch-evoked escape behavior are two common noninvasive assays used to determine the degree of muscular disorganization and locomotive impairment of zebrafish embryos during early development.

Analisi dei difetti muscolo scheletrico larvale Zebrafish da Birifrangenza e Touch-evocare Fuga risposta Saggi

Zebrafish (Danio rerio) have become a particularly effective tool for modeling human diseases affecting skeletal muscle, including muscular ...

Alternative Cultures for Human Pluripotent Stem Cell Production, Maintenance, and Genetic Analysis

Human pluripotent stem cells (hPSCs) hold great promise for regenerative medicine and biopharmaceutical applications. Currently, optimal culture and efficient expansion of large amounts of clinical-grade hPSCs are critical issues in hPSC-based therapies. Conventionally, hPSCs are propagated as colonies on both feeder and feeder-free culture systems. However, these methods have several major limitations, including low cell yields and generation of heterogeneously differentiated cells. To improve current hPSC culture methods, we have recently developed a new method, which is based on non-colony type monolayer (NCM) culture of dissociated single cells. Here, we present detailed NCM protocols based on the Rho-associated kinase (ROCK) inhibitor Y-27632. We also provide new information regarding NCM culture with different small molecules such as Y-39983 (ROCK I inhibitor), phenylbenzodioxane (ROCK II inhibitor), and thiazovivin (a novel ROCK inhibitor). We further extend our basic protocol to cultivate hPSCs on defined extracellular proteins such as the laminin isoform 521 (LN-521) without the use of ROCK inhibitors. Moreover, based on NCM, we have demonstrated efficient transfection or transduction of plasmid DNAs, lentiviral particles, and oligonucleotide-based microRNAs into hPSCs in order to genetically modify these cells for molecular analyses and drug discovery. The NCM-based methods overcome the major shortcomings of colony-type culture, and thus may be suitable for producing large amounts of homogeneous hPSCs for future clinical therapies, stem cell research, and drug discovery.

Here, we present human pluripotent stem cell (hPSC) culture protocols, based on non-colony type monolayer (NCM) growth of dissociated single cells. This new method, utilizing Rho-associated kinase inhibitors or the laminin isoform 521 (LN-521), is suitable for producing large amounts of homogeneous hPSCs, genetic manipulation, and drug discovery.

Le colture per pluripotenti umane alternative staminali produzione di celle, manutenzione e analisi genetica

Human pluripotent stem cells (hPSCs) hold great promise for regenerative medicine and biopharmaceutical applications. Currently, optimal culture and ...

Detection and Analysis of DNA Damage in Mouse Skeletal Muscle In Situ Using the TUNEL Method

Terminal deoxynucleotidyl transferase (TdT) deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) is the method of using the TdT enzyme to covalently attach a tagged form of dUTP to 3&#8217; ends of double- and single-stranded DNA breaks in cells. It is a reliable and useful method to detect DNA damage and cell death in situ. This video describes dissection, tissue processing, sectioning, and fluorescence-based TUNEL labeling of mouse skeletal muscle. It also describes a method of semi-automated TUNEL signal quantitation. Inherent normal tissue features and tissue processing conditions affect the ability of the TdT enzyme to efficiently label DNA. Tissue processing may also add undesirable autofluorescence that will interfere with TUNEL signal detection. Therefore, it is important to empirically determine tissue processing and TUNEL labeling methods that will yield the optimal signal-to-noise ratio for subsequent quantitation. The fluorescence-based assay described here provides a way to exclude autofluorescent signal by digital channel subtraction. The TUNEL assay, used with appropriate tissue processing techniques and controls, is a relatively fast, reproducible, quantitative method for detecting apoptosis in tissue. It can be used to confirm DNA damage and apoptosis as pathological mechanisms, to identify affected cell types, and to assess the efficacy of therapeutic treatments in vivo.

Detection and Analysis of DNA Damage in Mouse Skeletal Muscle In Situ Using the TUNEL Method

This video describes dissection, tissue processing, sectioning, and fluorescence-based TUNEL labeling of mouse skeletal muscle. It also describes a method for semi-automated analysis of TUNEL labeling.

Rilevamento e analisi del danno al DNA nel muscolo scheletrico mouse<em&gt; In Situ</em&gt; Utilizzo del metodo TUNEL

Terminal deoxynucleotidyl transferase (TdT) deoxyuridine triphosphate (dUTP) nick end labeling (TUNEL) is the method of using the TdT enzyme to covalently ...

Cryosectioning of Contiguous Regions of a Single Mouse Skeletal Muscle for Gene Expression and Histological Analyses

With this method, consecutive cryosections are collected to enable both microscopy applications for tissue histology and enrichment of RNA for gene expression using adjacent regions from a single mouse skeletal muscle. Typically, it is challenging to achieve adequate homogenization of small skeletal muscle samples because buffer volumes may be too low for efficient grinding applications, yet without sufficient mechanical disruption, the dense tissue architecture of muscle limits penetration of buffer reagents, ultimately causing low RNA yield. By following the protocol reported here, 30 &#956;m sections are collected and pooled allowing cryosectioning and subsequent needle homogenization to mechanically disrupt the muscle, increasing the surface area exposed for buffer penetration. The primary limitations of the technique are that it requires a cryostat, and it is relatively low throughput. However, high-quality RNA can be obtained from small samples of pooled muscle cryosections, making this method accessible for many different skeletal muscles and other tissues. Furthermore, this technique enables matched analyses (e.g., tissue histopathology and gene expression) from adjacent regions of a single skeletal muscle so that measurements can be directly compared across applications to reduce experimental uncertainty and to reduce replicative animal experiments necessary to source a small tissue for multiple applications.

Consecutive cryo-sections are collected to enable histological applications and enrichment of RNA for gene expression measurements using adjacent regions from a single mouse skeletal muscle. High-quality RNA is obtained from 20 - 30 mg of pooled cryosections and measurements are directly compared across applications.

Criosezionamento di regioni contigue di un muscolo scheletrico mouse unico per l&#39;espressione genica e analisi istologiche

With this method, consecutive cryosections are collected to enable both microscopy applications for tissue histology and enrichment of RNA for gene ...

Trans-inner Cell Mass Injection of Embryonic Stem Cells Leads to Higher Chimerism Rates

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current blastocyst injection protocol. Here we report that a simple rotation of the embryo, and injection through Trans-Inner cell mass (TICM) increased the percentage of chimeric mice from 31% to 50%, with no additional equipment or further specialized training. 26 different inbred clones, and 35 total clones were injected over a period of 9 months. There was no significant difference in either pregnancy rate or recovery rate of embryos between traditional injection techniques and TICM. Therefore, without any major alteration in the injection process and a simple positioning of the blastocyst and injecting through the ICM, releasing the ES cells into the blastocoel cavity can potentially improve the quantity of chimeric production and subsequent germline transmission.

Here we present a protocol to increase chimera production without the use of new equipment. A simple orientation change of the embryo for injection can increase the number of embryos produced, and potentially reduce the timeline to germline transmission.

Trans-inner Cell Mass iniezione delle cellule staminali embrionali porta a tassi più elevati di chimerismo

In an effort to increase efficiency in the creation of genetically modified mice via ES Cell methodologies, we present an adaptation to the current ...

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A)

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer progression. How the chromosomal location and function of a centromere (i.e., centromere identity) are determined and participate in accurate chromosome segregation is a fundamental question. CENP-A is proposed to be the non-DNA indicator (epigenetic mark) of centromere identity, and CENP-A ubiquitylation is required for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability.
Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-CENP-A K124R mutant suggesting that ubiquitylation at a different lysine is induced because of the EYFP tagging in the CENP-A K124R mutant protein. Lysine 306 (K306) ubiquitylation in EYFP-CENP-A K124R was successfully identified, which corresponds to lysine 56 (K56) in CENP-A through mass spectrometry analysis. A caveat is discussed in the use of GFP/EYFP or the tagging of high molecular weight protein as a tool to analyze the function of a protein. Current technical limit is also discussed for the detection of ubiquitylated bands, identification of site-specific ubiquitylation(s), and visualization of ubiquitylation in living cells or a specific single cell during the whole cell cycle.
The method of mass spectrometry analysis presented here can be applied to human CENP-A protein with different tags and other centromere-kinetochore proteins. These combinatory methods consisting of several assays/analyses could be recommended for researchers who are interested in identifying functional roles of ubiquitylation.

Mass Spectrometry Analysis to Identify Ubiquitylation of EYFP-tagged CENP-A EYFP-CENP-A

CENP-A ubiquitylation is an important requirement for CENP-A deposition at the centromere, inherited through dimerization between cell division, and indispensable to cell viability. Here we describe mass spectrometry analysis to identify ubiquitylation of EYFP-tagged CENP-A (EYFP-CENP-A) protein.

Analisi della spettrometria di massa per identificare l'ubiquilazione del CENP-A con tag EYFP (EYFP-CENP-A)

Studying the structure and the dynamics of kinetochores and centromeres is important in understanding chromosomal instability (CIN) and cancer ...

A Mouse Model of Lumbar Spine Instability

Intervertebral disc degeneration (IDD) is a common pathological change leading to low back pain. Appropriate animal models are desired for understanding the pathological processes and evaluating new drugs. Here, we introduced a surgically induced lumbar spine instability (LSI) mouse model that develops IDD starting from 1 week post operation. In detail, the mouse under anesthesia was operated by low back skin incision, L3&#8211;L5 spinous processes exposure, detachment of paraspinous muscles, resection of processes and ligaments, and skin closure. L4&#8211;L5 IVDs were chosen for the observation. The LSI model develops lumbar IDD by porosity and hypertrophy in endplates at an early stage, decrease in intervertebral disc volume, shrinkage in nucleus pulposus at an intermediate stage, and bone loss in lumbar vertebrae (L5) at a later stage. The LSI mouse model has the advantages of strong operability, no requirement of special equipment, reproducibility, inexpensive, and relatively short period of IDD development. However, LSI operation is still a trauma that causes inflammation within the first week post operation. Thus, this animal model is suitable for study of lumbar IDD.

We developed a lumbar intervertebral disc degeneration mouse model by resection of L3&#8211;L5 spinous processes along with supra- and inter-spinous ligaments and detachment of paraspinous muscles.

Un modello di topo di instabilità della colonna lombare

Intervertebral disc degeneration (IDD) is a common pathological change leading to low back pain. Appropriate animal models are desired for understanding ...