Thanks to Brad Lackford for assistance optimizing some of the techniques described in this manuscript.

1. Manutenzione di macrofagi linee cellulari <ol><li> Grow RAW264.7 e linee cellulari J774A.1 in DMEM supplementato con siero fetale bovino al 10% (FBS), a 37 ° C in presenza del 5% di CO 2. Per aiutare a mantenere la sterilità, aggiungere 1% di penicillina / streptomicina (penna / strep) ai media (anche se questo non è strettamente necessario). </li><li> Passaggio fondamentale: Assicurarsi che i macrofagi sono in crescita in uno stato di salute per la trasfezione efficiente e siRNA-indotta knockdown gene. Utilizzare le cellule tra i passaggi 3 e 10 dopo lo scongelamento fresco, come queste righe macrofagi presentano la migliore efficienza di trasfezione e mantenere solida la sopravvivenza dopo la trasfezione in questa fase; non utilizzare un numero di brano superiore (&gt; 20), come l&#39;efficienza di trasfezione e Silenziamento genico entrambi diminuiscono notevolmente. </li><li> Per ottimizzare la trasfezione di siRNA, cellule piastra a 20% di confluenza e crescere uno o due giorni fino a quando le cellule raggiungono non confluenza superiore all&#39;80%. Cellule Overgrown non trasfettare efficposi- zione ergonomica. </li></ol> 2. Programmazione del 96 pozzetti sistema Shuttle per la trasfezione <ol><li> Avviare il software di navetta a 96 pozzetti sul computer collegato alla navetta. Seleziona nuovo file di parametri nel menu File in alto a sinistra. </li><li> Selezionare i pozzetti che verranno transfettate sul visualizzata 96 pozzetti schematica. Un riquadro verde indica che i pozzi sono selezionati. </li><li> Selezionare il programma che corrisponde alla linea cellulare di macrofagi in uso (DS-136 per RAW264.7 o DS-130 per J774A.1) e selezionare Applica, che si trova al di sotto della piastra a 96 pozzetti nel diagramma. Si noti che dopo la selezione di un programma, i pozzetti sulla piastra schematica saranno di colore blu scuro. Cerchi vuoti indicano pozzi che non è stato assegnato un programma e non saranno scioccati. </li></ol> 3. Preparazione dei Reagenti per la trasfezione <ol><li> Preparare la soluzione Nucleofector ™ di lavoro mescolando linea cellulare SF 96 e soluzione Nucleofector ™con l&#39;intero contenuto della provetta supplemento allegata. Lasciare i reagenti misti equilibrare a temperatura ambiente prima dell&#39;uso. Conservare la soluzione in eccesso completa Nucleofector ™ a 4 ° C per un massimo di 3 mesi per un utilizzo futuro. </li><li> Preriscaldare il salino DMEM, RPMI-1640, 0,25% tripsina / EDTA, e tampone fosfato (PBS) a 37 ° C prima di preparare i macrofagi per la trasfezione. </li><li> Preparare il siRNA per trasfezione di scongelamento sul ghiaccio. Per ridurre al minimo il numero di disgelo congelamento del siRNA, congelare nuovi siRNA in aliquote la prima volta che vengono utilizzati. </li><li> In esperimenti iniziali, utilizzare siRNA ad una dose relativamente alta di 2 micron (diluito 1:10 da 20 micron scorte). Successivamente titolare siRNA che inducono robusta gene knockdown fino a dosi più basse, anche se sono necessarie dosi più elevate di solito per un efficiente atterramento gene nei macrofagi rispetto ad altri tipi di cellule. NOTA: siRNA sono disponibili da diverse fonti; abbastanza robusto knockdown gene può essere ottenutoutilizzando SmartPools siGenome, che sono quattro piscine di siRNA mirati ogni gene. Come controllo negativo, usare una delle varie piscine non-targeting siRNA o siRNA. </li><li> Per monitorare l&#39;efficienza di trasfezione, transfettare sia il plasmide pmaxGFP di controllo (fornito nel kit Amaxa) o siRNA fluorescenza marcata in parallelo ai siRNA sperimentali. Aspettatevi 30-50% trasfezione del plasmide GFP (analizzati mediante microscopia o citometria a flusso il giorno dopo trasfezione) e&gt; 99% trasfezione di fluorescenza marcata siRNA (analizzati mediante citometria di flusso immediatamente dopo la trasfezione e recupero). </li></ol> 4. Preparazione dei macrofagi per la trasfezione <ol><li> Staccare macrofagi aderenti dalle piastre di coltura cellulare mediante tripsinizzazione. Aspirare i media e lavare le cellule due volte con 10 ml di PBS. Dopo aver rimosso la PBS, incubare le cellule con pre-riscaldato 0,25% tripsina / EDTA (1 ml / 10 cm Piatto) per 1-2 minuti fino a quando le cellule iniziano a staccarsi. Agitare gentilmente la piastra e spostare la soluzione durante l&#39;incubazione per massimizzare tripsinizzazione. </li><li> Dopo l&#39;incubazione, aggiungere 9 ml supporto DMEM + FBS, mescolare delicatamente su e giù, e raccogliere le cellule pipettando in una provetta sterile. </li><li> Contare il numero di macrofagi isolati utilizzando un emocitometro. Aspettatevi circa 10 milioni di macrofagi ogni 10 cm Piatto. Calcolare il numero totale di macrofagi necessari; ciascun pozzetto sulla navetta 96 pozzetti richiede 200.000 cellule. Ricordarsi di aggiungere un valore di celle a pochi pozzi in più &#39;per consentire perdite di pipettaggio. </li><li> Pipettare il numero calcolato di cellule in una provetta da centrifuga. Centrifugare le cellule per 10 min a 150 xg a temperatura ambiente. Non centrifugare troppo in fretta come questo diminuirà la salute dei macrofagi e l&#39;efficienza di trasfezione. </li></ol> 5. Nucleofection dei macrofagi con siRNA <ol><li> Utilizzando uno sterile a 96 pozzetti piastra rotonda inferiore (che facilita la miscelazione, riducendo al minimo la perdita di reagente), aggiungere 2 ml di ogni siRNA a ciascun pozzetto per essere trasfette. Nota: A seconda del numero di siRNA, questo può essere effettuato durante la fase di centrifugazione macrofagi. </li><li> Aspirare il supporto dalle cellule centrifugati. Risospendere delicatamente le cellule in soluzione Nucleofector ™ SF (contenenti la soluzione supplemento), con 20 pl per 200.000 cellule pellet. Una volta risospeso, utilizzare immediatamente le cellule per la trasfezione ottimale. </li><li> Trasferire cellule risospese in un trogolo sterili; usando una pipetta multicanale, trasferimento 20 microlitri della miscela cellulare risospeso in ciascun pozzetto della piastra a 96 pozzetti contenente la siRNA. Mescolare delicatamente pipettando su e giù. </li><li> Trasferire 20 ml di miscela di cellule / siRNA in ben 96 piastra Nucleocuvette ™ passaggio fondamentale:. Evitare la generazione di bolle durante la fase di trasferimento in quanto ciò può indurre errori durante Nucleofection. </li><li> Dopo aver posizionato tutti i campioni sperimentali nella piastra trasfezione, coprire la piastra a 96 pozzetti con il coperchio in dotazione e very toccare delicatamente su una superficie dura per rimuovere eventuali bolle dai campioni. </li><li> Posizionare piastra a 96 pozzetti con coperchio in ben 96 navetta Nucleofector e selezionare &#39;caricare e avviare&#39; in basso a destra della finestra del programma. Prima di Nucleofection, seguire la richiesta del programma per salvare i risultati. Nota: Durante il processo di Nucleofection, pozzi tranfected con successo saranno raffigurati sul 96 pozzetti schema sullo schermo da un cerchio verde con un segno più. Un cerchio rosso con segno meno indica un errore, molto probabilmente a causa di bolle o mis-stato aggiunto il corretto volume di reagenti. </li></ol> 6. Recupero e placcatura dei macrofagi <ol><li> Subito dopo Nucleofection, con una pipetta multicanale, aggiungere 80 ml di pre-riscaldato (37 ° C) RMP1-1640 media per ciascun pozzetto. Aggiungere il supporto al lato di ogni pozzetto, consentendo al supporto di mescolare lentamente con le cellule trasfettate, che sono molto delicati in questa fase. Non aggiungere i media troppo in fretta, in modo daridurre notevolmente la redditività. </li><li> Posizionare le piastre a 96 pozzetti con campioni trasfettati e RPMI-1640 in un incubatore 37 ° C con il 5% di CO 2 per 2 min; questo è fondamentale per permettere alle cellule di recuperare prima di ulteriori manipolazioni. </li><li> Rimuovere la piastra a 96 pozzetti dall&#39;incubatore e trasferire accuratamente la miscela da ciascun pozzetto in una piastra di coltura tissutale a 96 pozzetti usando una pipetta multicanale. </li><li> Utilizzando una pipetta multicanale, aggiungere 100 ml di pre-riscaldato (37 ° C) DMEM + FBS medio in ciascun pozzetto. </li><li> Incubare la piastra di coltura tissutale a 96 pozzetti con i campioni in un incubatore 37 ° C con il 5% di CO 2 per 24-36 ore (ottimizzare i tempi esatti per i singoli siRNA, anche se questo intervallo di tempo in generale funziona bene). </li></ol> 7. La stimolazione dei macrofagi con LPS <ol><li> Dopo il 24-36 ore post-Nucleofection incubazione, preparare LPS (o altro PAMPs) in mezzi freschi. Preparare abbastanza terreno fresco per tutti i pozzi (200 ml media / pozzetto della piastra a 96 pozzetti, più un piccolo extra per il pipettaggio). Diluire LPS ad una concentrazione finale di 20 ng / ml in DMEM + FBS. </li><li> Supporti con attenzione aspirare dalla piastra a 96 pozzetti e aggiungere il supporto di fresco contenente LPS alle cellule. </li><li> Monitorare la risposta a LPS o altri PAMPs in vari momenti dopo la stimolazione. 6 ore è sufficiente a generare una robusta risposta citochina infiammatoria di citochine come IL-6 e TNFa. </li></ol> 8. Monitoraggio della risposta immunitaria indotta Innata, Gene Knockdown e vitalità nei macrofagi <ol><li> Per monitorare LPS-indotta la produzione di citochine, pipettare il surnatante dalle cellule in una piastra di archiviazione da 96 pozzetti. La produzione di citochine può essere misurato con ELISA. </li><li> Una volta che il surnatante viene rimosso, monitorare la vitalità cellulare con diacetato di fluoresceina (quando spaccati dalle esterasi cellulari in cellule vive, questo composto diventa fluorescente). Identificare siRNA che hanno come target i geni che controllano la vitalità cellulare tramite til suo approccio. Nota: il processo di transfezione stesso dovrebbe avere scarso effetto sulla vitalità se eseguita correttamente. <ol><li> Aggiungere fluoresceina diacetato (5 mg / ml magazzino in acetone) a ciascun pozzetto (diluizione 1: 100 in PBS finale). </li><li> Incubare a temperatura ambiente per 1-5 minuti e quindi monitorare la fluorescenza nelle cellule utilizzando un lettore di piastre (460 nm di eccitazione, emissione 515 nm). </li><li> Opzionale: Per garantire che la fluorescenza nei pozzetti è uniforme, lisare le cellule utilizzando tamponi, come RIPA; ciò fornisce un segnale fluorescente uniforme nel pozzo, come alcuni lettori di piastre sono configurati per controllare solo una piccola parte del pozzo; se le cellule non sono placcati uniformemente, la fluoresceina diacetato potrebbe dare una lettura imprecisa. </li></ol></li><li> In alternativa al monitoraggio vitalità cellulare, monitorare gene siRNA indotta knockdown da qPCR utilizzando RNA derivato dalle cellule aderenti. <ol><li> Dopo il surnatante viene rimosso dalle cellule (punto 8.1), pubblicitàd Buffer RLT (che viene utilizzato per la lisi e la conservazione di RNA) direttamente alle cellule aderenti per lisare loro. </li><li> Isolare RNA utilizzando un kit di preparazione RNA come il RNeasy mini-kit, e utilizzare qPCR con primer gene-specifici per monitorare gene knockdown rispetto al trattamento di controllo siRNA. Utilizzare primer per Βactin o GAPDH per la normalizzazione. </li></ol></li><li> Come ulteriore alternativa per monitorare altri aspetti della risposta immunitaria innata, monitorare la capacità fagocitica dei macrofagi aggiungendo marcato con FITC E. particelle coli direttamente sulla cellule aderenti con un kit. In seguito il protocollo del produttore, che richiede solo un paio d&#39;ore, monitorare l&#39;assorbimento fagocitaria utilizzando un lettore di piastre o microscopia. </li></ol>

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Gli autori dichiarano di non avere interessi finanziari in competizione. Questo articolo è stato sponsorizzato da Lonza, Inc.

Numerosi studi sono stati pubblicati in cui i singoli geni sono stati presi di mira da siRNA in macrofagi murini. Mentre trasfezione lipidico-mediata è stato utilizzato per fornire siRNA di linee cellulari di macrofagi su base individuale, questi metodi soffrono di potenziali effetti sulla vitalità, limitata knockdown gene, e la variabilità da gene a gene. Per sviluppare analisi più robusti che potrebbero essere utilizzati ai geni della moda medio o alto-rendimento obiettivo, abbiamo ottimizzato le tecniche che util...

In questo protocollo, si descrivono i metodi efficaci per inibire i geni in linee cellulari di macrofagi del mouse utilizzando siRNA e monitorare gli effetti di questi trattamenti sulla risposta immunitaria innata. Queste procedure vengono eseguite in formato a 96 pozzetti, consentendo schermi RNAi in modo medio o high-throughput. In risposta alle infezioni, gli esseri umani montare una risposta immunitaria innata immediata e una risposta immunitaria adattativa lento ma più preciso. Questa rapida risposta immunitaria innata coinvolge il reclutamento e l&#39;attivazione delle cellule immunitarie innate fagociti, tra cui i macrofagi 1. Classicamente macrofagi attivati ​​sono coinvolti nelle risposte infiammatorie acute e producono proteine ​​antimicrobiche e composti, citochine e chemochine, e presentano antigeni 2,3. In alternativa macrofagi attivati ​​svolgono un ruolo nella regolazione del sistema immunitario, mantenendo la tolleranza, la riparazione dei tessuti e la guarigione delle ferite 4-8. A causa della loro vasta gamma di funzioni, I macrofagi possono svolgere un ruolo in numerose malattie tra cui l&#39;aterosclerosi, artrite, cancro e 9. Pertanto, lo studio dei macrofagi è stata un&#39;area chiave di ricerca per un certo tempo in un&#39;ampia varietà di campi malattia. Nonostante la loro importanza nella risposta immunitaria innata, i macrofagi può essere difficile cellule con cui lavorare. In particolare, è difficile ottenere trasfezione efficiente utilizzando reagenti lipidici nei macrofagi senza tossicità associata 10,11. Inoltre, anche quando siRNA è efficiente consegnato macrofagi, la robustezza del gene RNAi indotta atterramento spesso può essere abbastanza moderato e può variare da gene a gene. Per superare queste sfide tecniche, abbiamo ottimizzato la trasfezione e tecniche di atterramento 12-16 in due linee cellulari di macrofagi del mouse, RAW264.7 17 e J774A.1 18. Questo approccio utilizza la Amaxa Nucleofector 96 pozzetti Sistema navetta per la trasfezione; questo sistemautilizza una combinazione di reagenti specializzati e elettroporazione per trasfettare cellule in formato a 96 pozzetti 19. A seguito di trasfezione, si descrivono i metodi per massimizzare il recupero delle cellule e la vitalità e per massimizzare la successiva gene knockdown siRNA-indotta. Per illustrare l&#39;utilità di questo approccio, si descrive un protocollo per la consegna di siRNA a queste linee cellulari di macrofagi, stimolare queste cellule con lipopolisaccaride (LPS), e monitorare la risposta immunitaria innata a livello della produzione di numerose citochine pro-infiammatorie. Forniamo dati di esempio in cui TARGET famiglia dei recettori Toll-like (TLR), i cui membri percepire LPS e altri modelli molecolari patogeni associati (PAMP), per regolare l&#39;immunità innata.

<table border="0" cellpadding="0" cellspacing="0" >
	<tbody>
		<tr >
			<td >Amaxa nucleofector 96-well shuttle system</td>
			<td>Lonza</td>
			<td>AAM-1001S</td>
		<td></td></tr>
		<tr >
			<td >Amaxa SF cell line 96-well nucleofector kit</td>
			<td>Lonza</td>
			<td>V4SC-2096</td>
		<td></td></tr>
		<tr >
			<td >RAW264.7 mouse macrophage cell line</td>
			<td>ATCC</td>
			<td>TIB-71</td>
		<td></td></tr>
		<tr >
			<td >J774A.1 mouse macrophage cell line</td>
			<td>ATCC</td>
			<td>TIB-67</td>
		<td></td></tr>
		<tr >
			<td >siGenome smartpool siRNA</td>
			<td>Dharmacon</td>
			<td>varies depending on gene</td>
		<td></td></tr>
		<tr >
			<td >Non-targeting control siRNA pool</td>
			<td>Dharmacon</td>
			<td>D-001206-13-20</td>
		<td></td></tr>
		<tr >
			<td >Block-iT fluorescent oligo for electrooration</td>
			<td>Invitrogen</td>
			<td>13750062</td>
		<td></td></tr>
		<tr >
			<td >Ultrapure E. coli O111:B4 LPS</td>
			<td>List Biological Laboratories</td>
			<td>421</td>
		<td></td></tr>
		<tr >
			<td >DMEM, high glucose</td>
			<td>Invitrogen</td>
			<td>11995-065</td>
		<td></td></tr>
		<tr >
			<td >RPM1-1640</td>
			<td>Invitrogen</td>
			<td>11875-093</td>
		<td></td></tr>
		<tr >
			<td >Penicillin-Streptomycin Solution (Pen/Strep)</td>
			<td>Fisher</td>
			<td>SV30010</td>
		<td></td></tr>
		<tr >
			<td >0.25% Trypsin-EDTA</td>
			<td>Invitrogen</td>
			<td>25200072</td>
		<td></td></tr>
		<tr >
			<td >96 well tissue culture plates</td>
			<td>Fisher</td>
			<td>07-200-89 </td>
		<td></td></tr>
		<tr >
			<td >96 well round bottom sterile plates (not coated)</td>
			<td>Fisher</td>
			<td>07-200-745</td>
		<td></td></tr>
		<tr >
			<td >Mouse IL-6 Duoset ELISA kit</td>
			<td>R&#38;D Biosystems</td>
			<td>DY406</td>
		<td></td></tr>
		<tr >
			<td >Mouse TNFa Duoset ELISA kit</td>
			<td>R&#38;D Biosystems</td>
			<td>DY410</td>
		<td></td></tr>
		<tr >
			<td >Fluorescein diacetate</td>
			<td>Sigma-Aldrich</td>
			<td>F7378</td>
		<td></td></tr>
		<tr >
			<td >RLT Bufer</td>
			<td>Qiagen</td>
			<td>79216</td>
		<td></td></tr>
		<tr >
			<td >Rneasy mini kit</td>
			<td>Qiagen</td>
			<td>74134</td>
		<td></td></tr>
		<tr >
			<td >Vybrant Phagocytosis Assay Kit</td>
			<td>Invitrogen</td>
			<td>V-6694</td>
		<td></td></tr>
	</tbody>
</table>

using rna-interference to investigate the innate immune response in mouse macrophages

Macrophages are key phagocytic innate immune cells. When macrophages encounter a pathogen, they produce antimicrobial proteins and compounds to kill the pathogen, produce various cytokines and chemokines to recruit and stimulate other immune cells, and present antigens to stimulate the adaptive immune response. Thus, being able to efficiently manipulate macrophages with techniques such as RNA-interference (RNAi) is critical to our ability to investigate this important innate immune cell. However, macrophages can be technically challenging to transfect and can exhibit inefficient RNAi-induced gene knockdown. In this protocol, we describe methods to efficiently transfect two mouse macrophage cell lines (RAW264.7 and J774A.1) with siRNA using the Amaxa Nucleofector 96-well Shuttle System and describe procedures to maximize the effect of siRNA on gene knockdown. Moreover, the described methods are adapted to work in 96-well format, allowing for medium and high-throughput studies. To demonstrate the utility of this approach, we describe experiments that utilize RNAi to inhibit genes that regulate lipopolysaccharide (LPS)-induced cytokine production.

Per dimostrare l&#39;efficienza di trasfezione usando questo approccio, abbiamo monitorato assorbimento di marcata con FITC siRNA usando un citometro a flusso (Figura 1). Per illustrare l&#39;utilità del nostro approccio per il monitoraggio della risposta immunitaria innata, abbiamo trasfettato siRNA mirate note innate geni regolatori del sistema immunitario nella linea cellulare di macrofagi RAW264.7, stimolato le cellule con LPS, e poi monitorato la produzione delle citoc...

Watch this Scientific Journal Video about Using RNA-interference to Investigate the Innate Immune Response in Mouse Macrophages at JoVE.com

Using RNA-interference to Investigate the Innate Immune Response in Mouse Macrophages

In this protocol, we describe methods to efficiently transfect murine macrophage cell lines with siRNAs using the Amaxa Nucleofector 96-well Shuttle System, stimulate the macrophages with lipopolysaccharide, and monitor the effects on inflammatory cytokine production.

Usando RNA-interferenza per Indagare sulla risposta immunitaria innata in mouse macrofagi

Macrophages are key phagocytic innate immune cells.  When macrophages encounter a pathogen, they produce antimicrobial proteins and compounds to kill the ...

using-rna-interference-to-investigate-innate-immune-response-mouse

Research

JoVE Journal

Immunology and Infection

10.6K Views.  National Jewish Health and University of Colorado School of Medicine. In this protocol, we describe methods to efficiently transfect murine macrophage cell lines with siRNAs using the Amaxa Nucleofector 96-well Shuttle System, stimulate the macrophages with lipopolysaccharide, and monitor the effects on inflammatory cytokine production.

Video: Using RNA-interference to Investigate the Innate Immune Response in Mouse Macrophages

RNA Interference in Ticks

Ticks are obligate hematophagous ectoparasites of wild and domestic animals and humans, and are considered to be second worldwide to mosquitoes as vectors of human diseases1 and the most important vectors affecting cattle industry worldwide2. Ticks are classified in the subclass Acari, order Parasitiformes, suborder Ixodida and are distributed worldwide from Arctic to tropical regions3. Despite efforts to control tick infestations, these ectoparasites remain a serious problem for human and animal health4,5.
RNA interference (RNAi)6 is a nucleic acid-based reverse genetic approach that involves disruption of gene expression in order to determine gene function or its effect on a metabolic pathway. Small interfering RNAs (siRNAs) are the effector molecules of the RNAi pathway that is initiated by double-stranded RNA (dsRNA) and results in a potent sequence-specific degradation of cytoplasmic mRNAs containing the same sequence as the dsRNA trigger7-9. Post-transcriptional gene silencing mechanisms initiated by dsRNA have been discovered in all eukaryotes studied thus far, and RNAi has been rapidly developed in a variety of organisms as a tool for functional genomics studies and other applications10.
RNAi has become the most widely used gene-silencing technique in ticks and other organisms where alternative approaches for genetic manipulation are not available or are unreliable5,11. The genetic characterization of ticks has been limited until the recent application of RNAi12,13. In the short time that RNAi has been available, it has proved to be a valuable tool for studying tick gene function, the characterization of the tick-pathogen interface and the screening and characterization of tick protective antigens14. Herein, a method for RNAi through injection of dsRNA into unfed ticks is described. It is likely that the knowledge gained from this experimental approach will contribute markedly to the understanding of basic biological systems and the development of vaccines to control tick infestations and prevent transmission of tick-borne pathogens15-19.

A method for RNA interference (RNAi) by injection of dsRNA into unfed ticks is described. RNAi is the most widely used gene-silencing technique in ticks where the use of other methods of genetic manipulation has been limited.

RNA interferenza nelle zecche

Ticks are obligate hematophagous ectoparasites of wild and domestic animals and humans, and are considered to be second worldwide to mosquitoes as vectors ...

Ricerca

Immunologia e infezioni

Seven Steps to Stellate Cells

Hepatic stellate cells are liver-resident cells of star-like morphology and are located in the space of Disse between liver sinusoidal endothelial cells and hepatocytes1,2. Stellate cells are derived from bone marrow precursors and store up to 80% of the total body vitamin A1, 2. Upon activation, stellate cells differentiate into myofibroblasts to produce extracellular matrix, thus contributing to liver fibrosis3. Based on their ability to contract, myofibroblastic stellate cells can regulate the vascular tone associated with portal hypertension4. Recently, we demonstrated that hepatic stellate cells are potent antigen presenting cells and can activate NKT cells as well as conventional T lymphocytes5. 

 Here we present a method for the efficient preparation of hepatic stellate cells from mouse liver. Due to their perisinusoidal localization, the isolation of hepatic stellate cells is a multi-step process. In order to render stellate cells accessible to isolation from the space of Disse, mouse livers are perfused in situ with the digestive enzymes Pronase E and Collagenase P. Following perfusion, the liver tissue is subjected to additional enzymatic treatment with Pronase E and Collagenase P in vitro. Subsequently, the method takes advantage of the massive amount of vitamin A-storing lipid droplets in hepatic stellate cells. This feature allows the separation of stellate cells from other hepatic cell types by centrifugation on an 8% Nycodenz gradient. The protocol described here yields a highly pure and homogenous population of stellate cells. Purity of preparations can be assessed by staining for the marker molecule glial fibrillary acidic protein (GFAP), prior to analysis by fluorescence microscopy or flow cytometry. Further, light microscopy reveals the unique appearance of star-shaped hepatic stellate cells that harbor high amounts of lipid droplets. 


 Taken together, we present a detailed protocol for the efficient isolation of hepatic stellate cells, including representative images of their morphological appearance and GFAP expression that help to define the stellate cell entity.

Here we describe a method for the isolation of hepatic stellate cells from mouse liver. For stellate cell purification, mouse livers are digested in situ and in vitro by pronase-collagenase treatment prior to density gradient centrifugation. This technique yields highly pure hepatic stellate cells.

Sette passi per Stellate Cellule

Hepatic stellate cells are liver-resident  cells of star-like morphology and are located in the space of Disse between  liver sinusoidal endothelial cells ...

An Introduction to Parasitic Wasps of Drosophila and the Antiparasite Immune Response

Most known parasitoid wasp species attack the larval or pupal stages of Drosophila. While Trichopria drosophilae infect the pupal stages of the host (Fig. 1A-C), females of the genus Leptopilina (Fig. 1D, 1F, 1G) and Ganaspis (Fig. 1E) attack the larval stages. We use these parasites to study the molecular basis of a biological arms race. Parasitic wasps have tremendous value as biocontrol agents. Most of them carry virulence and other factors that modify host physiology and immunity. Analysis of Drosophila wasps is providing insights into how species-specific interactions shape the genetic structures of natural communities. These studies also serve as a model for understanding the hosts' immune physiology and how coordinated immune reactions are thwarted by this class of parasites.
The larval/pupal cuticle serves as the first line of defense. The wasp ovipositor is a sharp needle-like structure that efficiently delivers eggs into the host hemocoel. Oviposition is followed by a wound healing reaction at the cuticle (Fig. 1C, arrowheads). Some wasps can insert two or more eggs into the same host, although the development of only one egg succeeds. Supernumerary eggs or developing larvae are eliminated by a process that is not yet understood. These wasps are therefore referred to as solitary parasitoids.
Depending on the fly strain and the wasp species, the wasp egg has one of two fates. It is either encapsulated, so that its development is blocked (host emerges; Fig. 2 left); or the wasp egg hatches, develops, molts, and grows into an adult (wasp emerges; Fig. 2 right). L. heterotoma is one of the best-studied species of Drosophila parasitic wasps. It is a "generalist," which means that it can utilize most Drosophila species as hosts1. L. heterotoma and L. victoriae are sister species and they produce virus-like particles that actively interfere with the encapsulation response2. Unlike L. heterotoma, L. boulardi is a specialist parasite and the range of Drosophila species it utilizes is relatively limited1. Strains of L. boulardi also produce virus-like particles3 although they differ significantly in their ability to succeed on D. melanogaster1. Some of these L. boulardi strains are difficult to grow on D. melanogaster1 as the fly host frequently succeeds in encapsulating their eggs. Thus, it is important to have the knowledge of both partners in specific experimental protocols.
In addition to barrier tissues (cuticle, gut and trachea), Drosophila larvae have systemic cellular and humoral immune responses that arise from functions of blood cells and the fat body, respectively. Oviposition by L. boulardi activates both immune arms1,4. Blood cells are found in circulation, in sessile populations under the segmented cuticle, and in the lymph gland. The lymph gland is a small hematopoietic organ on the dorsal side of the larva. Clusters of hematopoietic cells, called lobes, are arranged segmentally in pairs along the dorsal vessel that runs along the anterior-posterior axis of the animal (Fig. 3A). The fat body is a large multifunctional organ (Fig. 3B). It secretes antimicrobial peptides in response to microbial and metazoan infections.
Wasp infection activates immune signaling (Fig. 4)4. At the cellular level, it triggers division and differentiation of blood cells. In self defense, aggregates and capsules develop in the hemocoel of infected animals (Fig. 5)5,6. Activated blood cells migrate toward the wasp egg (or wasp larva) and begin to form a capsule around it (Fig. 5A-F). Some blood cells aggregate to form nodules (Fig. 5G-H). Careful analysis reveals that wasp infection induces the anterior-most lymph gland lobes to disperse at their peripheries (Fig. 6C, D).
We present representative data with Toll signal transduction pathway components Dorsal and Sp&auml;tzle (Figs. 4,5,7), and its target Drosomycin (Fig. 6), to illustrate how specific changes in the lymph gland and hemocoel can be studied after wasp infection. The dissection protocols described here also yield the wasp eggs (or developing stages of wasps) from the host hemolymph (Fig. 8).

An Introduction to Parasitic Wasps of Drosophila and the Antiparasite Immune Response

Parasitoid (parasitic) wasps constitute a major class of natural enemies of many insects including Drosophila melanogaster. We will introduce the techniques to propagate these parasites in Drosophila spp. and demonstrate how to analyze their effects on immune tissues of Drosophila larvae.

An Introduction to vespe parassite di<em&gt; Drosophila</em&gt; E la risposta immunitaria antiparassitari

Most known parasitoid wasp species attack the larval or pupal stages of Drosophila. While Trichopria drosophilae infect the pupal stages of the host (Fig. ...

Intravital Imaging of the Mouse Thymus using 2-Photon Microscopy

Two-photon Microscopy (TPM) provides image acquisition in deep areas inside tissues and organs. In combination with the development of new stereotactic tools and surgical procedures, TPM becomes a powerful technique to identify "niches" inside organs and to document cellular "behaviors" in live animals. While intravital imaging provides information that best resembles the real cellular behavior inside the organ, it is both more laborious and technically demanding in terms of required equipment/procedures than alternative ex vivo imaging acquisition. Thus, we describe a surgical procedure and novel "stereotactic" organ holder that allows us to follow the movements of Foxp3+ cells within the thymus.
Foxp3 is the master regulator for the generation of regulatory T cells (Tregs). Moreover, these cells can be classified according to their origin: ie. thymus-differentiated Tregs are called "naturally-occurring Tregs" (nTregs), as opposed to peripherally-converted Tregs (pTregs). Although significant amount of research has been reported in the literature concerning the phenotype and physiology of these T cells, very little is known about their in vivo interactions with other cells. This deficiency may be due to the absence of techniques that would permit such observations. The protocol described in this paper provides a remedy for this situation.
Our protocol consists of using nude mice that lack an endogenous thymus since they have a punctual mutation in the DNA sequence that compromises the differentiation of some epithelial cells, including thymic epithelial cells. Nude mice were gamma-irradiated and reconstituted with bone marrows (BM) from Foxp3-KIgfp/gfp mice. After BM recovery (6 weeks), each animal received embryonic thymus transplantation inside the kidney capsule. After thymus acceptance (6 weeks), the animals were anesthetized; the kidney containing the transplanted thymus was exposed, fixed in our organ holder, and kept under physiological conditions for in vivo imaging by TPM. We have been using this approach to study the influence of drugs in the generation of regulatory T cells.

We have developed novel laboratory tools and protocols for intravital imaging acquisition of the thymus. Our technique should help in the identification of &#x201C;niches&#x201D; within the thymus where T cell development occurs.

Imaging intravitale del Timo mouse utilizzando 2-Photon Microscopy

Two-photon Microscopy (TPM) provides image acquisition in deep areas inside tissues and organs. In combination with the development of new stereotactic ...

Quantitative Measurement of the Immune Response and Sleep in Drosophila

A complex interaction between the immune response and host behavior has been described in a wide range of species. Excess sleep, in particular, is known to occur as a response to infection in mammals 1 and has also recently been described in Drosophila melanogaster2. It is generally accepted that sleep is beneficial to the host during an infection and that it is important for the maintenance of a robust immune system3,4. However, experimental evidence that supports this hypothesis is limited4, and the function of excess sleep during an immune response remains unclear. We have used a multidisciplinary approach to address this complex problem, and have conducted studies in the simple genetic model system, the fruitfly Drosophila melanogaster. We use a standard assay for measuring locomotor behavior and sleep in flies, and demonstrate how this assay is used to measure behavior in flies infected with a pathogenic strain of bacteria. This assay is also useful for monitoring the duration of survival in individual flies during an infection. Additional measures of immune function include the ability of flies to clear an infection and the activation of NF&kappa;B, a key transcription factor that is central to the innate immune response in Drosophila. Both survival outcome and bacterial clearance during infection together are indicators of resistance and tolerance to infection. Resistance refers to the ability of flies to clear an infection, while tolerance is defined as the ability of the host to limit damage from an infection and thereby survive despite high levels of pathogen within the system5. Real-time monitoring of NF&kappa;B activity during infection provides insight into a molecular mechanism of survival during infection. The use of Drosophila in these straightforward assays facilitates the genetic and molecular analyses of sleep and the immune response and how these two complex systems are reciprocally influenced.

Quantitative Measurement of the Immune Response and Sleep in Drosophila

To understand a link between the immune response and behavior, we describe a method to measure locomotor behavior in Drosophila during bacterial infection as well as the ability of flies to mount an immune response by monitoring survival, bacterial load, and real-time activity of a key regulator of innate immunity, NF&kappa;B.

Misurazione quantitativa della risposta immunitaria e nel sonno<em&gt; Drosophila</em

A complex interaction between the immune response and  host behavior has been described in a wide range of species. Excess sleep, in  particular, is known ...

Quantification of the Respiratory Burst Response as an Indicator of Innate Immune Health in Zebrafish

The phagocyte respiratory burst is part of the innate immune response to pathogen infection and involves the production of reactive oxygen species (ROS). ROS are toxic and function to kill phagocytized microorganisms. In vivo quantification of phagocyte-derived ROS provides information regarding an organism's ability to mount a robust innate immune response. Here we describe a protocol to quantify and compare ROS in whole zebrafish embryos upon chemical induction of the phagocyte respiratory burst. This method makes use of a non-fluorescent compound that becomes fluorescent upon oxidation by ROS. Individual zebrafish embryos are pipetted into the wells of a microplate and incubated in this fluorogenic substrate with or without a chemical inducer of the respiratory burst. Fluorescence in each well is quantified at desired time points using a microplate reader. Fluorescence readings are adjusted to eliminate background fluorescence and then compared using an unpaired t-test. This method allows for comparison of the respiratory burst potential of zebrafish embryos at different developmental stages and in response to experimental manipulations such as protein knockdown, overexpression, or treatment with pharmacological agents. This method can also be used to monitor the respiratory burst response in whole dissected kidneys or cell preparations from kidneys of adult zebrafish and some other fish species. We believe that the relative simplicity and adaptability of this protocol will complement existing protocols and will be of interest to researchers who seek to better understand the innate immune response.

The innate immune response protects organisms against pathogen infection. A critical component of the innate immune response, the phagocyte respiratory burst, generates reactive oxygen species that kill invading microorganisms. We describe a respiratory burst assay that quantifies reactive oxygen species produced when the innate immune response is chemically induced.

Quantificazione della risposta Burst respiratoria come un indicatore di Innate Immune Salute in Zebrafish

The phagocyte respiratory burst is part of the innate immune response to  pathogen infection and involves the production of reactive oxygen species (ROS). ...

Dissecting Innate Immune Signaling in Viral Evasion of Cytokine Production

In response to a viral infection, the host innate immune response is activated to up-regulate gene expression and production of antiviral cytokines. Conversely, viruses have evolved intricate strategies to evade and exploit host immune signaling for survival and propagation. Viral immune evasion, entailing host defense and viral evasion, provides one of the most fascinating and dynamic interfaces to discern the host-virus interaction. These studies advance our understanding in innate immune regulation and pave our way to develop novel antiviral therapies.
Murine &#947;HV68 is a natural pathogen of murine rodents. &#947;HV68 infection of mice provides a tractable small animal model to examine the antiviral response to human KSHV and EBV of which perturbation of in vivo virus-host interactions is not applicable. Here we describe a protocol to determine the antiviral cytokine production. This protocol can be adapted to other viruses and signaling pathways.
Recently, we have discovered that &#947;HV68 hijacks MAVS and IKK&#946;, key innate immune signaling components downstream of the cytosolic RIG-I and MDA5, to abrogate NF&#922;B activation and antiviral cytokine production. Specifically, &#947;HV68 infection activates IKK&#946; and that activated IKK&#946; phosphorylates RelA to accelerate RelA degradation. As such, &#947;HV68 efficiently uncouples NF&#922;B activation from its upstream activated IKK&#946;, negating antiviral cytokine gene expression. This study elucidates an intricate strategy whereby the upstream innate immune activation is intercepted by a viral pathogen to nullify the immediate downstream transcriptional activation and evade antiviral cytokine production.

We describe a protocol to measure the antiviral cytokine production in mice infected with a model herpesvirus, murine gamma herpesvirus 68 (&#947;HV68) that is closely-related to human Kaposi&#8217;s sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV). Utilizing genetically modified mouse strains and mouse embryonic fibroblasts (MEFs), we assessed the antiviral cytokine production both in vivo and ex vivo. &#8220;Reconstituting&#8221; the expression of innate immune components in knockout embryonic fibroblasts by lentiviral transduction, we further pinpoint specific innate immune molecules and dissect the key signaling events that differentially regulate the antiviral cytokine production.

Dissezione Innate Immune Signaling in Evasion virale di produzione di citochine

In response to a viral infection, the host innate immune response is activated to up-regulate gene expression and production of antiviral cytokines. ...

In Vitro Analysis of Myd88-mediated Cellular Immune Response to West Nile Virus Mutant Strain Infection

An attenuated West Nile virus (WNV), a nonstructural (NS) 4B-P38G mutant, induced higher innate cytokine and T cell responses than the wild-type WNV in mice. Recently, myeloid differentiation factor 88 (MyD88) signaling was shown to be important for initial T cell priming and memory T cell development during WNV NS4B-P38G mutant infection. In this study, two flow cytometry-based methods &#8211; an in vitro T cell priming assay and an intracellular cytokine staining (ICS) &#8211; were utilized to assess dendritic cells (DCs) and T cell functions. In the T cell priming assay, cell proliferation was analyzed by flow cytometry following co-culture of DCs from both groups of mice with carboxyfluorescein succinimidyl ester (CFSE) - labeled CD4+ T cells of OTII transgenic mice. This approach provided an accurate determination of the percentage of proliferating CD4+ T cells with significantly improved overall sensitivity than the traditional assays with radioactive reagents. A microcentrifuge tube system was used in both cell culture and cytokine staining procedures of the ICS protocol. Compared to the traditional tissue culture plate-based system, this modified procedure was easier to perform at biosafety level (BL) 3 facilities. Moreover, WNV- infected cells were treated with paraformaldehyde in both assays, which enabled further analysis outside BL3 facilities. Overall, these in vitro immunological assays can be used to efficiently assess cell-mediated immune responses during WNV infection.

In Vitro Analysis of Myd88-mediated Cellular Immune Response to West Nile Virus Mutant Strain Infection

Two flow cytometry-based methods &#8211; an in vitro T cell priming assay and intracellular cytokine staining were utilized to measure antigen presenting capacity of dendritic cells and antigen-specific T cell responses to a West Nile virus mutant infection in mice.

In Analisi Vitro di Myd88 mediata Cellular Immune Response to West Nile virus mutante Strain Infezione

An attenuated West Nile virus (WNV), a nonstructural (NS) 4B-P38G mutant, induced higher innate cytokine and T cell responses than the wild-type WNV in ...

Non-invasive Imaging of the Innate Immune Response in a Zebrafish Larval Model of Streptococcus iniae Infection

The aquatic pathogen, Streptococcus iniae, is responsible for over 100 million dollars in annual losses for the aquaculture industry and is capable of causing systemic disease in both fish and humans. A better understanding of S. iniae disease pathogenesis requires an appropriate model system. The genetic tractability and the optical transparency of the early developmental stages of zebrafish allow for the generation and non-invasive imaging of transgenic lines with fluorescently tagged immune cells. The adaptive immune system is not fully functional until several weeks post fertilization, but zebrafish larvae have a conserved vertebrate innate immune system with both neutrophils and macrophages. Thus, the generation of a larval infection model allows the study of the specific contribution of innate immunity in controlling S. iniae infection.
The site of microinjection will determine whether an infection is systemic or initially localized. Here, we present our protocols for otic vesicle injection of zebrafish aged 2-3 days post fertilization as well as our techniques for fluorescent confocal imaging of infection. A localized infection site allows observation of initial microbe invasion, recruitment of host cells and dissemination of infection. Our findings using the zebrafish larval model of S. iniae infection indicate that zebrafish can be used to examine the differing contributions of host neutrophils and macrophages in localized bacterial infections. In addition, we describe how photolabeling of immune cells can be used to track individual host cell fate during the course of infection.

Non-invasive Imaging of the Innate Immune Response in a Zebrafish Larval Model of Streptococcus iniae Infection

Here, we present a protocol for the generation and imaging of a localized bacterial infection in the zebrafish otic vesicle.

Imaging non invasiva della risposta immunitaria innata in un modello di Zebrafish larvale<em&gt; Streptococcus iniae</em&gt; Infezione

The aquatic pathogen, Streptococcus iniae, is responsible for over 100 million dollars in annual losses for the aquaculture industry and is capable of ...

Using Phylogenetic Analysis to Investigate Eukaryotic Gene Origin

Phylogenetic analysis uses nucleotide or amino acid sequences or other parameters, such as domain sequences and three-dimensional structure, to construct a tree to show the evolutionary relationship among different taxa (classification units) at the molecular level. Phylogenetic analysis can also be used to investigate domain relationships within an individual taxon, particularly for organisms that have undergone substantial change in morphology and physiology, but for which researchers lack fossil evidence due to the organisms&#39; long evolutionary history or scarcity of fossilization.
In this text, a detailed protocol is described for using the phylogenetic method, including amino acid sequence alignment using Clustal Omega, and subsequent phylogenetic tree construction using both Maximum Likelihood (ML) of Molecular Evolutionary Genetics Analysis (MEGA) and Bayesian Inference via MrBayes. To investigate the origin of eukaryotic Sugars Will Eventually be Exported Transporters (SWEET) genes, 228 SWEETs including 35 SWEET proteins from unicellular eukaryotes and 57 SemiSWEET proteins from prokaryotes were analyzed. Interestingly, SemiSWEETs were found in prokaryotes, but SWEETs were found in eukaryotes. Two phylogenetic trees constructed using theoretically distinct methods have consistently&#160;suggested that the first eukaryotic SWEET gene might stem from the fusion of a bacterial SemiSWEET gene and an archaeal SemiSWEET gene.&#160;It is worth noting that one should be cautious to draw a conclusion based only on phylogenetic analysis, although it is useful to explain the underlying relationship between different taxa, which is difficult or even impossible to discern through experimental means.

A method of constructing a phylogenetic tree based on sequence homology of SWEETs from eukaryotes and SemiSWEETs from prokaryotes is described. Phylogenetic analysis is a useful tool for explaining the evolutionary relatedness between homologous proteins or genes from different organism groups.

Utilizzando l'analisi filogenetica di indagare l'origine genica negli eucarioti

Phylogenetic analysis uses nucleotide or amino acid sequences or other parameters, such as domain sequences and three-dimensional structure, to construct ...

Methods Article

Usando RNA-interferenza per Indagare sulla risposta immunitaria innata in mouse macrofagi