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

1. Mantenimiento de líneas celulares de macrófagos <ol><li> Crecer RAW264.7 y líneas de células J774A.1 en DMEM suplementado con suero bovino fetal al 10% (FBS) a 37 ºC en presencia de 5% de CO 2. Para ayudar a mantener la esterilidad, añadir 1% de penicilina / estreptomicina (pen / strep) a los medios de comunicación (aunque esto no es estrictamente necesario). </li><li> Paso crítico: Asegúrese de que los macrófagos están creciendo en un estado saludable para la transfección eficiente y inducida por siRNA desmontables de genes. Utilice células entre pasajes 3 y 10 después de la descongelación fresco, ya que estas líneas de macrófagos exhiben la mejor eficiencia de transfección y mantienen robustas de supervivencia después de la transfección en esta etapa; no utilice un número de pases más alto (&gt; 20), como la eficacia de transfección de genes y Derribo tanto disminuyen grandemente. </li><li> Para optimizado transfección siRNA, células de la placa a 20% de confluencia y crecen uno o dos días hasta que las células alcanzan no más de 80% de confluencia. Células Overgrown no transfectar eficiently. </li></ol> 2. Programación del Sistema de traslado de 96 pocillos para la transfección <ol><li> Inicie el software de enlace de 96 pozos en el ordenador conectado a la lanzadera. Seleccione el nuevo archivo de parámetros en el menú archivo de la parte superior izquierda. </li><li> Destacar los pozos que se transfectaron en la que se muestra de 96 pocillos esquemática placa. Un cuadro verde indica que los pozos sean seleccionados. </li><li> Seleccione el programa que corresponde a la línea celular de macrófagos que se utiliza (DS-136 para RAW264.7 o DS-130 para J774A.1) y seleccione Aplicar, situado por debajo de la placa de 96 pocillos diagramada. Tenga en cuenta que después de seleccionar un programa, los pocillos de la placa esquemática serán de color azul oscuro. Círculos vacíos indican pozos que no han sido asignados un programa y no ser sorprendido. </li></ol> 3. Preparación de los reactivos para la transfección <ol><li> Preparar la solución Nucleofector ™ trabaja mezclando línea celular SF 96 bien-solución Nucleofector ™con todo el contenido del tubo suplemento cerrado. Dejar que los reactivos mezclados se equilibren a temperatura ambiente antes de su uso. Almacenar el exceso de solución completa Nucleofector ™ a 4 ºC hasta por 3 meses para un uso futuro. </li><li> Pre-caliente la solución salina DMEM, RPMI-1640, 0,25% de tripsina / EDTA, y fosfato tamponada con (PBS) a 37 ºC antes de la preparación de los macrófagos para la transfección. </li><li> Prepare el siRNA para la transfección por descongelar en hielo. Con el fin de minimizar el número de deshielo de congelación del siRNA, congelar en alícuotas nuevas siRNAs la primera vez que se utilizan. </li><li> En los experimentos iniciales, utilice siRNA a una dosis relativamente alta de 2 M (diluido desde 01:10 20 mM acciones). Posteriormente se valora siRNAs que inducen gen robusta desmontables a dosis más bajas, aunque se necesitan dosis más altas típicamente para una eficiente desmontables génica en macrófagos en comparación con otros tipos de células. NOTA: Los siRNAs están disponibles de muchas fuentes; bastante robusto caída gen se puede obtenerutilizando SmartPools siGenome, que son grupos de cuatro siRNAs dirigidos a cada gen. Como control negativo, utilice cualquiera de varias piscinas no de metas de siRNA o siRNAs. </li><li> Para monitorear la eficiencia de transfección, transfectar o bien el plásmido pmaxGFP control (proporcionado en los kits de Amaxa) o siRNAs marcados con fluorescencia en paralelo a los siRNAs experimentales. Esperar 30-50% de la transfección del plásmido GFP (ensayada por microscopía o citometría de flujo el día después de la transfección) y&gt; 99% de la transfección de ARNsi marcado con fluorescencia (ensayada mediante citometría de flujo inmediatamente después de la transfección y recuperación). </li></ol> 4. Preparación de los macrófagos para la transfección <ol><li> Separe los macrófagos adherentes de las placas de cultivo de células por tripsinización. Aspirar los medios de comunicación y se lavan las células dos veces con 10 ml de PBS. Después de retirar el PBS, incubar las células con pre-calentado 0,25% de tripsina / EDTA (1 ml / placa de 10 cm) durante 1-2 minutos hasta que las células comienzan a desprenderse. Golpear suavemente la placa y mover el Solución durante la incubación para maximizar la tripsinización. </li><li> Después de la incubación, añadir 9 ml de medio DMEM + FBS, mezclar suavemente hacia arriba y hacia abajo, y recoger las células por pipeteo en un tubo estéril. </li><li> Cuente el número de macrófagos aislados utilizando un hemocitómetro. Esperar aproximadamente 10 millones de macrófagos por placa de 10 cm. Calcular el número total de macrófagos necesarios; cada pocillo en el transbordador de 96 pocillos requiere 200.000 células. Recuerde que debe añadir el valor de las células de algunos pozos adicionales &quot;para permitir que las pérdidas de pipeteo. </li><li> Pipetear el número calculado de las células en un tubo de centrífuga. Centrifugar las células durante 10 min a 150 xg a temperatura ambiente. No centrifugar demasiado rápido ya que esto disminuirá la salud de los macrófagos y la eficacia de transfección. </li></ol> 5. Nucleofection de macrófagos con siRNA <ol><li> Usando una placa de 96 pocillos de fondo redondo estéril (que facilita la mezcla y reducir al mínimo la pérdida de reactivo), añadir 2 l de cada siRNA a cada pocillo para ser transfeja. Nota: Dependiendo del número de siRNAs, esto puede llevarse a cabo durante la etapa de centrifugación de macrófagos. </li><li> Aspirar el medio de las células centrifugadas. Resuspender suavemente las células en solución Nucleofector ™ SF (que contiene la solución de suplemento), utilizando 20 l por 200.000 células sedimentadas. Una vez resuspendido, utilizar las células inmediatamente para la transfección óptima. </li><li> Transferencia de células resuspendidas en un canal estéril; utilizando una pipeta multicanal, la transferencia de 20 l de la mezcla de células resuspendido en cada pocillo de la placa de 96 pocillos que contiene la siRNAs. Mezclar suavemente con la pipeta hacia arriba y abajo. </li><li> Transferencia de 20 l de la mezcla de células / siRNA en la placa de 96 pocillos Nucleocuvette ™ paso crítico:. A evitar la generación de burbujas durante la etapa de transferencia, ya que esto puede inducir a errores durante Nucleofection. </li><li> Después de colocar todas las muestras experimentales en la placa de la transfección, cubrir la placa de 96 pocillos con la tapa proporcionada y very toque suavemente sobre una superficie dura para eliminar las burbujas de las muestras. </li><li> Coloque la placa de 96 pocillos con tapa en el 96 pocillos de transporte Nucleofector y seleccione &quot;cargar y comenzar &#39;en la parte inferior derecha de la pantalla del programa. Antes de Nucleofection, siga la línea de programa para guardar los resultados. Nota: Durante el proceso de Nucleofection, pozos transfectadas con éxito serán representados en el 96 pocillos esquemática en la pantalla por un círculo verde con un signo más. Un círculo rojo con signos menos indica un error, muy probablemente debido a las burbujas o mis-pipeteado el volumen correcto de los reactivos. </li></ol> 6. Recuperación y galjanoplastia de macrófagos <ol><li> Inmediatamente después de Nucleofection, usando una pipeta multicanal, añadir 80 l de precalentado (37 ºC) RMP1-1640 medios de comunicación a cada pocillo. Añadir los medios de comunicación a un lado de cada pocillo, permitiendo que los medios se mezclan lentamente con las células transfectadas, que son muy delicada en esta etapa. No agregue los medios de comunicación demasiado rápido, ya que estodisminuir en gran medida la viabilidad. </li><li> Colocar las placas de 96 pocillos con muestras transfectadas y RPMI-1640 en una incubadora a 37 ºC con 5% de CO2 durante 2 min; esto es fundamental para permitir que las células se recuperen antes de la manipulación adicional. </li><li> Retire la placa de 96 pocillos de la incubadora y transferir cuidadosamente la mezcla de cada pocillo en una placa de cultivo tisular de 96 pocillos usando una pipeta multicanal. </li><li> Usando una pipeta multicanal, añadir 100 l de precalentado (37 ºC) medio DMEM + FBS a cada pocillo. </li><li> Incubar la placa de cultivo tisular de 96 pocillos con las muestras en un incubador de 37 ºC con 5% de CO 2 durante 24-36 hr (optimizar el tiempo exacto para siRNAs individuales, aunque este intervalo de tiempo generalmente funciona bien). </li></ol> 7. estimulación de los macrófagos con LPS <ol><li> Tras el 24-36 horas después de la Nucleofection incubación, preparar LPS (u otros PAMP) en medio fresco. Preparar suficiente medio fresco para todos los pozos (200 l mEDIA / pocillo de la placa de 96 pocillos, más un poco más por pipeteo). Diluir LPS a una concentración final de 20 ng / ml en DMEM + FBS. </li><li> Medios de comunicación cuidadosamente aspirado de la placa de 96 pocillos y se suman los medios de comunicación fresca que contiene los LPS a las células. </li><li> Monitorear la respuesta a LPS u otros PAMP en diversos momentos después de la estimulación. 6 hr es suficiente para generar una respuesta de citoquinas inflamatoria robusta para citoquinas tales como IL-6 o TNF. </li></ol> 8. Control de la Respuesta Inmune Innata inducida, Gene Derribo y viabilidad en los macrófagos <ol><li> Para monitorizar la producción de citoquinas inducida por LPS, una pipeta el sobrenadante de las células en una placa de almacenamiento de 96 pocillos. La producción de citocinas se puede medir por ELISA. </li><li> Una vez que se retira el sobrenadante, controlar la viabilidad celular utilizando diacetato de fluoresceína (cuando se escinde por esterasas celulares en células vivas, este compuesto se convierte en fluorescente). Identificar siRNAs que se dirigen a los genes que controlan la viabilidad celular mediante la tsu enfoque. Nota: el proceso de transfección en sí debe tener poco efecto sobre la viabilidad si se realiza correctamente. <ol><li> Añadir diacetato de fluoresceína (5 mg / ml en acetona) a cada pocillo (1: 100 dilución final en PBS). </li><li> Incubar a temperatura ambiente durante uno a cinco minutos y luego controlar la fluorescencia en las células utilizando un lector de placas (460 nm de excitación, 515 nm de emisión). </li><li> Opcional: Para asegurarse de que la fluorescencia en los pozos es uniforme, lisan las células usando tampones tales como RIPA; esto proporciona una señal fluorescente uniforme en el pozo, como algunos lectores de placas están configuradas para supervisar sólo una pequeña porción del pozo; si las células no se siembran de manera uniforme, el diacetato de fluoresceína podría dar una lectura incorrecta. </li></ol></li><li> Como una alternativa a la vigilancia de la viabilidad celular, monitorear génica inducida siRNA-desmontables por qPCR usando ARN derivado de las células adherentes. <ol><li> Después se retira el sobrenadante de las células (paso 8.1 anterior), add tampón RLT (que se utiliza para la lisis y la preservación de RNA) directamente a las células adherentes para lisar ellos. </li><li> Aislar ARN utilizando un kit de preparación de ARN, como el mini-kit RNeasy, y el uso de qPCR con cebadores específicos de genes para controlar gen relativa desmontables para controlar el tratamiento de siRNA. Utilice cebadores a Βactin o GAPDH para la normalización. </li></ol></li><li> Como otra alternativa para controlar otros aspectos de la respuesta inmune innata, supervisar la capacidad fagocítica de los macrófagos mediante la adición de FITC-etiquetados E. partículas coli directamente sobre las células adherentes utilizando un kit. Siguiendo el protocolo del fabricante, que tiene sólo unas pocas horas, controlar la absorción de fagocitosis utilizando un lector de placas o microscopía. </li></ol>

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Los autores declaran que no tienen intereses financieros en competencia. Este artículo fue patrocinado por Lonza, Inc.

Numerosos estudios han sido publicados en los que los genes individuales han sido blanco de siRNA en macrófagos murinos. Mientras que la transfección mediada por lípidos ha sido utilizado para entregar siRNA a las líneas celulares de macrófagos sobre una base individual, estos métodos sufren de los efectos potenciales sobre la viabilidad, la caída limitada de genes, y la variabilidad del gen a gen. Para desarrollar ensayos más robustos que podrían ser utilizados para apuntar a genes de la moda de mediano o de a...

En este protocolo, se describen los métodos eficaces para inhibir genes en líneas celulares de macrófagos de ratón utilizando siRNAs y controlar los efectos de estos tratamientos en la respuesta inmune innata. Estos procedimientos se realizan en formato de 96 pocillos, lo que permite pantallas de RNAi en la moda de mediano o alto rendimiento. En respuesta a la infección, los seres humanos montar una respuesta inmune innata inmediata y una respuesta inmune adaptativa más lento pero más específico. Esta rápida respuesta inmune innata implica el reclutamiento y la activación de las células inmunes innatas fagocíticas incluyendo macrófagos 1. Macrófagos activados Clásicamente están implicados en las respuestas inflamatorias agudas y producen proteínas antimicrobianas y compuestos, citocinas y quimiocinas, y presentar antígenos 2,3. Macrófagos alternativamente activados desempeñan un papel en la regulación de la inmunidad, el mantenimiento de la tolerancia, la reparación de tejidos, la curación de heridas y 4-8. Debido a su amplia gama de funciones, Los macrófagos pueden desempeñar un papel en numerosas enfermedades, incluyendo la aterosclerosis, artritis, y cáncer 9. Así, el estudio de los macrófagos ha sido un área clave de la investigación durante algún tiempo en una amplia variedad de campos de la enfermedad. A pesar de su importancia en la respuesta inmune innata, los macrófagos pueden ser un reto para trabajar con células. En particular, es difícil obtener la transfección eficiente utilizando reactivos de lípidos en los macrófagos sin toxicidad asociada 10,11. Además, incluso cuando siRNA se entrega de manera eficiente a los macrófagos, la robustez del gen inducida por RNAi desmontables a menudo puede ser bastante moderado y puede variar de un gen a gen. Para superar estos desafíos técnicos, hemos optimizado la transfección y técnicas de derribo 12-16 en dos líneas celulares de macrófagos de ratón, RAW264.7 17 y 18 J774A.1. Este enfoque utiliza el sistema de traslado de 96 pocillos Amaxa Nucleofector para la transfección; este sistemautiliza una combinación de reactivos especializados y electroporación para transfectar células en formato de 96 pocillos 19. Después de la transfección, se describen los métodos para maximizar la recuperación celular y la viabilidad y para maximizar la posterior caída de genes inducida por siRNA. Para ilustrar la utilidad de este enfoque, se describe un protocolo para la entrega siRNA a estas líneas celulares de macrófagos, estimular estas células con lipopolisacárido (LPS), y controlar la respuesta inmune innata en el nivel de producción de varias citocinas pro-inflamatorias. Proporcionamos datos de la muestra en la que se dirigen a la familia de receptores de tipo Toll (TLR), cuyos miembros detectar LPS y otros patógenos asociados a patrones moleculares (PAMPs), para regular la inmunidad 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.

Para demostrar la eficacia de la transfección usando este enfoque, que supervisó la captación de ARNsi marcado con FITC utilizando un citómetro de flujo (Figura 1). Para ilustrar la utilidad de nuestro enfoque para el seguimiento de la respuesta inmune innata, transfectadas siRNAs dirigidos a genes reguladores inmunes innatas conocidas en la línea celular de macrófagos RAW264.7, estimulamos las células con LPS, y luego supervisó la producción de las citoquinas pro-i...

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.

El uso de ARN de interferencia para Investigar la respuesta inmune innata en macrófagos de ratón

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 vistas.  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.

La interferencia de ARN en las garrapatas

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

Investigación

Inmunología e Infección

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.

Siete pasos para células estrelladas

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.

Una introducción a las avispas parasitarias de<em&gt; Drosophila</em&gt; Y la respuesta inmune antiparasitario

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.

Imagen intravital del timo de ratón utilizando 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.

Medición cuantitativa de la respuesta inmune y del sueño en<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.

Cuantificación de la respuesta estallido respiratorio como un indicador de la salud inmune innata en el pez cebra

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.

La disección de señalización inmune innata en Evasion Viral de la producción de citoquinas

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.

El análisis in vitro de la respuesta inmune celular Myd88 mediada por el Virus del Nilo Occidental cepa mutante Infección

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.

Imagen no invasiva de la respuesta inmune innata en un modelo de larvas de pez cebra de<em&gt; Streptococcus iniae</em&gt; Infección

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.

Utilizando el análisis filogenético para investigar origen de genes eucariotas

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