The authors would like to thank Mark Bishop, Mathew Zverev, Victoria Marsh-Durban, Adam Blackwood and Sylvie Robine. This work was funded by a programme grant from Cancer Research UK.

<ol>
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The authors have nothing to disclose.

Utilizando ratones transgénicos condicionales Cre-lox para diseccionar la función de los genes y las células es un enfoque comúnmente utilizado. Estos modelos se han utilizado con gran éxito en el intestino para identificar y caracterizar las células madre 2,4-6 y comprender su papel en la enfermedad 25. Para aprovechar al máximo estos modelos requiere una caracterización completa del sistema para permitir que los datos deben interpretarse correctamente. Una comprensión completa de estos sistemas es difícil de lograr debido a los genes rara vez ser específico para un tipo de célula solitario o ubicación, una falta de conocimiento biológico y la ineficiencia de los sistemas utilizados para inducir la expresión Cre. Los métodos descritos aquí demuestran cómo podemos superar estos problemas a través del diseño experimental y aplicación del conocimiento existente. Aunque hemos utilizado estos métodos para responder a una pregunta específica de investigación las técnicas que aquí se presenta es genérico y puede ser explotado para cualquier investigación que investiga el muridelgado ne. Preparación de tejido intestinal El paso fundamental para garantizar resultados sólidos es la recolección y procesamiento de los tejidos, que necesita ser procesada de una manera y de fijación oportunos protocolos estrictamente. Como casi todos los temas significativos aguas abajo se pueden atribuir a artefactos asociados con el secado del tejido y / o fijación incompleta. El tiempo es crucial para prevenir la degradación de la arquitectura del tejido y / o ácidos nucleicos y proteínas. Fijación incompleta o exceso de celo puede resultar en la pérdida de resolución histoquímica. Fijación incompleta por falta de tiempo o secciones demasiado gruesas para permitir la penetración fijador puede resultar en la pérdida de resolución dentro de las criptas intestinales que pueden observarse como una &quot;marca de la marea&quot; en el análisis IHC insuficiente. Además, es crucial que la fijación no se extiende por mucho tiempo, como β-catenina nuclear puede difundirse fuera del núcleo a menos de inmediato prorebajada y cera incrustado tras la fijación en formol. Papel de las células de Paneth en el nicho de ISC Los datos presentados aquí muestran efectivamente la importancia de las células de Paneth en la regeneración cripta en el intestino de adultos después de la pérdida de ISC. Sin embargo quedaba la posibilidad de que Ah-cre escatima una población de ISC que los objetivos T2 vil-Cre-ER. Tian et al. 26 demostraron elegantemente que los hi ISC LGR5 se sustituyen por una población de ISC reserva LGR5 del lo. Ahora parece probable que estos ISC se libran en el sistema de Ah-cre debido a la población de reserva de haber sido identificado como precursores de células secretoras 6,7. La importancia de la célula de Paneth madura en el apoyo a estos precursores de células secretoras cuando sea necesario para volver a un estado ISC queda por responder. Como las células de Paneth constituyen la ISC nicho 8 y desempeñar un papel en la regulación de las respuestas del ISC a la ingesta de calorías y la inflamación 27 28 sigue siendo probable que sus funciones de enfermería se extenderán a sus precursores. Nuevos enfoques y tecnologías para Efectivamente Modelo Humano Cáncer Colorrectal El descubrimiento de la ISC condujo a la identificación de los genes que están siendo utilizados para generar nuevos modelos de ratón para investigar el papel de los genes y las células en la biología y la enfermedad intestinal, revisado por Clarke et al 9. Las únicas limitaciones de esta técnica es la identificación de genes para expresar la proteína Cre. Actualmente ISC se investigan rutinariamente utilizando ratones transgénicos condicionales basados ​​en el patrón de expresión génica LGR5. Los ratones que expresan Cre a partir del promotor LGR5 se han utilizado para eliminar Apc, el gen más comúnmente mutado en el cáncer colorrectal (CRC), Lo que demuestra la ISC como la célula de origen 25. Selectivamente borrar otros genes CRC en estas células está proporcionando información sobre progresión de la enfermedad y se extendió por ejemplo. PTEN 29. Una mayor comprensión de la función de ISC está siendo recuperado por ablación específicamente LGR5 expresando células en ratones usando un receptor de toxina de la difteria humana gen (DTR) noqueó en el LGR5 locus 26. Otras estrategias usan el sistema Tet-O, ​​que permite la expresión reversible en curso de las proteínas mutantes 30. El uso de estas herramientas para modificar el gen (s) en diferentes células 31 y ubicaciones 32,33 se utiliza para comprender cómo iniciar el cáncer, el progreso y la metástasis 34. Alternativamente mutagénesis usando el sistema de la belleza transposón dormir es la identificación de nuevos controladores de CRC. El continuo desarrollo de los ratones, las técnicas y estrategias de alteración genética continúa desarrollando modelos relevantes más pacientes. Nueva métodos se han desarrollado para la caracterización de los epitelios intestinales y ISC. Caracterización de la proporción de tipos de células epiteliales se puede lograr utilizando citometría de flujo basado en la expresión diferencial de lectina y CD24 35. Potencialmente el mayor progreso en la biología comprensión ISC y su papel en la enfermedad se realizarán mediante el sistema vivo organoid ex cultura 36. Este sistema permite ISC normales y malignas a la cultura en 3D, donde se replican y se diferencian de una manera más fisiológicamente relevante. Se espera que estos permitirán a la prueba directa de las drogas en muestras de pacientes in vitro, allanando el camino para la medicina personalizada 37.

La superficie luminal del intestino de mamíferos características unidades de criptas y el dedo repitiendo como proyecciones, denominado vellosidades, que sobresalen en el lumen. Esta superficie es una lámina continua de los epitelios que se somete a auto-renovación completa aproximadamente cada 3 - 4 días 1. Este tejido dinámico con el apoyo de una población de células madre de ciclos rápidos (ISCS, también conocida como base de la cripta células columnares), que fueron identificados inicialmente por su expresión del gen LGR5 2,3. Estas células existen en un nicho especializado en el fondo de las criptas de Lieberkuhn. Inicialmente, el descubrimiento de que el ISC se ciclismo rápidamente fue discordante con la idea predominante de que una célula madre estaba en reposo en la naturaleza. Anterior a la identificación de la LGR5 + ISC se postuló que una población de células quiescentes etiqueta en la posición 4, en relación a la base de la cripta de retención, fueron el ISC 1. Investigaciones recientes hcomo ahora reconciliado estas observaciones demostrando que principalmente hay una piscina del ciclismo equipotente ISC en cada cripta cuyo destino se regulan por sus vecinos de 4,5. En el caso de que se pierdan estos pueden ser sustituidos por células en reposo que normalmente están comprometidos con el linaje secretora, pero puede volver a ISC si la población ISC está dañado 6. Vecinos ISC pueden ser o bien ISC o sus células hijas. Los ISC producen células hijas vírgenes que se multiplican y se diferencian en los tipos de células especializadas que forman la lámina epitelial que recubre la luz intestinal 1. La copa, enteroendocrina, enterocitos, penacho y células M migran hacia arriba a la superficie luminal donde proporcionan varias funciones de absorción y de regulación, sin embargo, las células de Paneth permanecen en el fondo de la cripta donde existen entremezclan con el ISC. En los últimos años se ha demostrado que una proporción de la Daught naïveer células destinadas a un linaje de secreción son etiquetas de reposo retener células LGR5 Lo capaces de revertir a un ISC sobre la lesión 6,7. Debido a su importancia en la regeneración cripta se colocó una prioridad en la comprensión de las interacciones entre el ISC y sus vecinos, en particular las células de Paneth. Las células de Paneth juegan un papel crucial en el nicho que apoya el ISC 8. Además de los productos bactericidas las células de Paneth producen moléculas de señalización que activan las vías que regulan la renovación ISC o diferenciación. Estudios previos demostraron que la LGR5 + ISC sólo puede existir cuando podrían competir por señales de nicho esenciales proporcionados por sus hijas células de Paneth 8. Estos estudios examinaron el papel de las células de Paneth en LGR5 normales + ISC y no en una situación en la que están dañadas y requieren la reposición de una población LGR5 lo. <pclass = &quot;jove_content&quot;&gt; Para entender la biología y el modelo de enfermedad intestinal examinamos el papel funcional de las células y / o genes utilizando modelos de ratones transgénicos 9,10. Frecuentemente, estos modelos utilizan la tecnología cre-lox para modificar condicionalmente gen (s) 9,10. Cre (causas recombinación) recombinasa es una recombinasa específica del sitio de la familia de la integrasa, aislado del bacteriófago P1. Cre cataliza la recombinación específica entre el sitio definido 34 pb &#39; Lox P &#39;(locus χ de P1 de cruce) sitios. Los ratones diseñados genéticamente para contener sitios LoxP que flanquean las regiones de interés, que tras la expresión de la recombinasa Cre son extirpados. La vinculación de la expresión del gen Cre a una célula o promotor específico del desarrollo permite la alteración que se hizo de una manera espacial 9,10, esto es especialmente útil en la superación de mutaciones letales embrionarios. Vincular aún más la expresión de Cre a una vía del receptor,que se puede activar artificialmente, permite alteraciones temporales. Utilizando esta tecnología nos inactivado el gen Catnb 11 en los epitelios intestinales. β-catenina, el producto del gen Catnb, es un regulador clave de la vía de señalización Wnt canónica que regula la homeostasis de ISC. Dos estudios anteriores utilizando esta estrategia produjeron resultados contradictorios 12,13. El estudio de FEVR et al. 12, demostró la pérdida de las células madre y la homeostasis intestinal. Considerando que el Ireland et al. 14 estudio informó que tras una reducción de la viabilidad celular del eje cripta-vellosidad fue repoblada a partir de células de tipo salvaje que expresan Catnb. La principal diferencia en estos estudios fue el promotor utilizado para expresar Cre en los epitelios intestinales. El FEVR et al., Estudio utilizó el promotor del gen vilina ligado al receptor de estrógeno que puede ser activado mediante la administración de tamoxifen (vil-Cre-ER T2) 15,16. En contraste Ireland et al., Utiliza el elemento promotor del gen del citocromo P450A1 rata (CYP1A1) para conducir la expresión Cre en respuesta a la β-naftoflavona xenobiótico (Ah-CRE). Las características de estos diferentes sistemas generan dos hipótesis para explicar estas diferentes observaciones. El primero que Catnb se elimina de manera más eficiente en el ISC usando el sistema T2 vil-Cre-ER en comparación con el Ah-cre, reduciendo así el número de ISC a niveles sub-repoblación. Alternativamente que era debido a la diferencia de eliminación Catnb en la población celular diferenciado. El sistema T2 vil-Cre-ER objetivos todas las células epiteliales de la cripta y vellosidad mientras que el sistema de Ah-cre únicos blancos las células no Paneth del nicho ISC y la cripta. Estos sistemas proporcionan herramientas ideales para examinar la behavior del ISC y su interacción con las células de Paneth. Aquí presentamos varios protocolos detallados basados ​​en la forma en que usamos estos sistemas para determinar que las células de Paneth juegan un papel crucial en la mediación de la respuesta intestinal a la lesión 17.

<table border="0" cellpadding="0" cellspacing="0">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr>
			<td>Acetate buffer</td>
			<td>*</td>
			<td>*</td>
			<td>To make 100ml: 4.8ml 0.2M Acetic acid, 45.2ml 0.2M Sodium acetate &#38; 50ml distilled water</td>
		</tr>
		<tr>
			<td>Acetic acid</td>
			<td>Fisher Scientific</td>
			<td>C/0400/PB17</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic anhydride</td>
			<td>Sigma</td>
			<td>A6404</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic anhydride solution</td>
			<td>*</td>
			<td>*</td>
			<td>2 M Acetic anhydride in 0.1 M triethanolamine hydrochloride</td>
		</tr>
		<tr>
			<td>Alcian Blue</td>
			<td>Sigma</td>
			<td>A5268</td>
			<td></td>
		</tr>
		<tr>
			<td>Alcian Blue ph2.5</td>
			<td>*</td>
			<td>*</td>
			<td>To make 500ml: 15ml acetic acid, 5g Alcian Blue &#38; 485ml distilled water</td>
		</tr>
		<tr>
			<td>anti-digoxigenin alkaline phosphatase conjugated antibody</td>
			<td>Abcam</td>
			<td>ab119345</td>
			<td></td>
		</tr>
		<tr>
			<td>B(beta)-Naphthoflavone</td>
			<td>Sigma</td>
			<td>N3633</td>
			<td>BNF, inject without allowing the solution to cool too much as compound will drop out of solution. Solution can be re-used &#8211; store at -20&#176;C between uses, do not reheat more than twice.</td>
		</tr>
		<tr>
			<td>Bloxall</td>
			<td>Vector Labs</td>
			<td>SP-6000</td>
			<td></td>
		</tr>
		<tr>
			<td>BM purple</td>
			<td>Roche</td>
			<td>11442074001</td>
			<td></td>
		</tr>
		<tr>
			<td>BSA</td>
			<td>Sigma</td>
			<td>A4503</td>
			<td>Bovine serum albumin</td>
		</tr>
		<tr>
			<td>Chloroform</td>
			<td>Fisher Scientific</td>
			<td>C/4920/17</td>
			<td></td>
		</tr>
		<tr>
			<td>Citrate Buffer/Antigen Unmasking Solution</td>
			<td>Vector Labs</td>
			<td>H-3300</td>
			<td></td>
		</tr>
		<tr>
			<td>Corn oil</td>
			<td>Sigma</td>
			<td>C8627</td>
			<td></td>
		</tr>
		<tr>
			<td>Demucifiying solution</td>
			<td>*</td>
			<td>*</td>
			<td>For 500ml: 50ml glycerol, 50ml Tris 0.1M pH8.8, 100ml EtOH, 300ml saline (0.9% NaCl in water), DTT 1.7g.&#160; Demucifying solution can be made in advance and stored, but DTT sholud be added just before incubation (340mg/100ml).</td>
		</tr>
		<tr>
			<td>DEPC treated water</td>
			<td>Life Technologies</td>
			<td>750023</td>
			<td></td>
		</tr>
		<tr>
			<td>DTT</td>
			<td>Sigma</td>
			<td>101509944</td>
			<td></td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Sigma</td>
			<td>O3690</td>
			<td>0.5M</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Fisher Scientific</td>
			<td>E/0650DF/17</td>
			<td></td>
		</tr>
		<tr>
			<td>Filter paper</td>
			<td>Whatman</td>
			<td>3000917</td>
			<td></td>
		</tr>
		<tr>
			<td>Formaldehyde</td>
			<td>Sigma</td>
			<td>F8775</td>
			<td></td>
		</tr>
		<tr>
			<td>Formalin&#160;</td>
			<td>Sigma</td>
			<td>SLBL11382V</td>
			<td>Neutral buffered formalin</td>
		</tr>
		<tr>
			<td>Formamide</td>
			<td>Sigma</td>
			<td>F5786</td>
			<td></td>
		</tr>
		<tr>
			<td>Glutaraldehye</td>
			<td>Sigma</td>
			<td>G6257</td>
			<td></td>
		</tr>
		<tr>
			<td>H2O2</td>
			<td>Sigma</td>
			<td>216763</td>
			<td></td>
		</tr>
		<tr>
			<td>Haematoxylin</td>
			<td>Raymond A Lamb</td>
			<td>12698616</td>
			<td></td>
		</tr>
		<tr>
			<td>HBSS</td>
			<td>Gibco</td>
			<td>14175-053</td>
			<td>HBSS (-MgCl2+; -CaCl2)</td>
		</tr>
		<tr>
			<td>Hybridisation buffer</td>
			<td>*</td>
			<td>*</td>
			<td>&#160;5&#215; SSC, 50% formamide, 5% SDS, 1 mg/ml heparin, 1 mg/ml calf liver tRNA</td>
		</tr>
		<tr>
			<td>Hydroquinone</td>
			<td>Sigma</td>
			<td>H9003</td>
			<td></td>
		</tr>
		<tr>
			<td>ImmPACT DAB Peroxidase</td>
			<td>Vector Labs</td>
			<td>SK-4105</td>
			<td></td>
		</tr>
		<tr>
			<td>Immpress HRP Anti-Mouse IgG Kit</td>
			<td>Vector Labs</td>
			<td>MP-7402</td>
			<td></td>
		</tr>
		<tr>
			<td>Immpress HRP Anti-Rabbit IgG Kit</td>
			<td>Vector Labs</td>
			<td>MP-7401</td>
			<td></td>
		</tr>
		<tr>
			<td>Intestinal tissue powder</td>
			<td>*</td>
			<td>*</td>
			<td>The small intestines of 5 adult mice were combined and homogenised in the minimum volume of ice cold PBS. 4 volumes of ice cold acetone were added to the homogenised intestine, which was mixed thoroughly and incubated on ice for 30 minutes. This was centrifuged and the pellet was washed using ice cold acetone. This was further centrifuged and the resulting pellet spread onto filter paper and allowed to dry. Once thoroughly dry the material was ground to a fine powder using a pestle and mortar.&#160;</td>
		</tr>
		<tr>
			<td>K-ferricyanide</td>
			<td>Sigma</td>
			<td>P-3667</td>
			<td></td>
		</tr>
		<tr>
			<td>K-ferrocyanide</td>
			<td>Sigma</td>
			<td>P3289</td>
			<td></td>
		</tr>
		<tr>
			<td>Levamisole</td>
			<td>Sigma</td>
			<td>L0380000</td>
			<td></td>
		</tr>
		<tr>
			<td>Methacarn</td>
			<td>*</td>
			<td>*</td>
			<td>60% Methanol:30% Chloroform:10% Acetic acid</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Fisher Scientific</td>
			<td>M/4000/17</td>
			<td></td>
		</tr>
		<tr>
			<td>MgCl2</td>
			<td>Sigma</td>
			<td>M8266</td>
			<td></td>
		</tr>
		<tr>
			<td>Normal goat serum</td>
			<td>Vector Labs</td>
			<td>S-1012</td>
			<td>NGS</td>
		</tr>
		<tr>
			<td>Normal rabbit serum</td>
			<td>Dako</td>
			<td>X0902</td>
			<td>NRS</td>
		</tr>
		<tr>
			<td>NTMT</td>
			<td>*</td>
			<td>*</td>
			<td>100 mM NaCl, 100 mM Tris HCl, 50 mM MgCl2, 0.1% Tween20, 2 mM Levamisole</td>
		</tr>
		<tr>
			<td>PAP pen</td>
			<td>Vector</td>
			<td>H-400</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Sigma</td>
			<td>P6148</td>
			<td></td>
		</tr>
		<tr>
			<td>PBT</td>
			<td>*</td>
			<td>*</td>
			<td>0.5M NaCl, 10mM TrisHCL pH7.5, 0.1% Tween 20</td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>Gibco</td>
			<td>15140-122</td>
			<td>100x solutiuon.</td>
		</tr>
		<tr>
			<td>Phosphate buffered saline (10x)</td>
			<td>Fisher Scientific</td>
			<td>BP3994</td>
			<td>Dilluted 1:10 with distilled water to make 1x</td>
		</tr>
		<tr>
			<td>PLL slides</td>
			<td>Sigma</td>
			<td>P0425-72EA</td>
			<td>Poly-L-lysine microscope slides</td>
		</tr>
		<tr>
			<td>Proteinase K</td>
			<td>Sigma</td>
			<td>P2308</td>
			<td></td>
		</tr>
		<tr>
			<td>Proteinase k solution</td>
			<td>*</td>
			<td>*</td>
			<td>Dilute Proteinase K at 200 &#181;g/ml in 50 mM Tris, 5 mM EDTA.</td>
		</tr>
		<tr>
			<td>Ralwax</td>
			<td>BDH</td>
			<td>36154 7N</td>
			<td></td>
		</tr>
		<tr>
			<td>Reducer Solution</td>
			<td>*</td>
			<td>*</td>
			<td>To make 100ml: 1g Hydroquinone, 5g sodium sulphite &#38; 100ml distilled water</td>
		</tr>
		<tr>
			<td>RnaseA</td>
			<td>Sigma</td>
			<td>R6148</td>
			<td></td>
		</tr>
		<tr>
			<td>Saline</td>
			<td>*</td>
			<td>*</td>
			<td>0.9% NaCl in distilled water</td>
		</tr>
		<tr>
			<td>SDS</td>
			<td>Sigma</td>
			<td>I3771</td>
			<td></td>
		</tr>
		<tr>
			<td>Sheep serum</td>
			<td>Sigma</td>
			<td>S3772</td>
			<td></td>
		</tr>
		<tr>
			<td>Silver nitrate</td>
			<td>Sigma</td>
			<td>S/1240/46</td>
			<td></td>
		</tr>
		<tr>
			<td>Silver solution</td>
			<td>*</td>
			<td>*</td>
			<td>To make 100ml: 10ml Acetate buffer, 87ml distilled water, 3ml 1% silver nitrate</td>
		</tr>
		<tr>
			<td>Sodium acetate</td>
			<td>Fisher Scientific</td>
			<td>S/2120/53</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Chloride</td>
			<td>Sigma</td>
			<td>S6753</td>
			<td>NaCl</td>
		</tr>
		<tr>
			<td>Sodium sulfite</td>
			<td>Sigma</td>
			<td>239321</td>
			<td></td>
		</tr>
		<tr>
			<td>SSC</td>
			<td>Sigma</td>
			<td>93017</td>
			<td>20x saline sodium citrate</td>
		</tr>
		<tr>
			<td>Surgical tape</td>
			<td>Fisher Scientific</td>
			<td>12960495</td>
			<td></td>
		</tr>
		<tr>
			<td>Tamoxifen</td>
			<td>Sigma</td>
			<td>T5648</td>
			<td>TAM, inject without allowing the solution to cool too much as compound will drop out of solution. Solution can be re-used &#8211; store at -20&#176;C between uses, do not reheat more than twice.</td>
		</tr>
		<tr>
			<td>TBS/T</td>
			<td>Cell Signalling</td>
			<td>#9997</td>
			<td></td>
		</tr>
		<tr>
			<td>Triethanolamine hydrochloride</td>
			<td>Sigma</td>
			<td>T1502</td>
			<td></td>
		</tr>
		<tr>
			<td>Tris-HCL</td>
			<td>Invitrogen</td>
			<td>15567-027</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween20</td>
			<td>Sigma</td>
			<td>TP9416</td>
			<td></td>
		</tr>
		<tr>
			<td>VectaMount</td>
			<td>Vector Labs</td>
			<td>H-5000</td>
			<td></td>
		</tr>
		<tr>
			<td>VectaShield Hardset mounting Medium with DAPI</td>
			<td>Vector Labs</td>
			<td>H-1500</td>
			<td></td>
		</tr>
		<tr>
			<td>Vectastain ABC Kit</td>
			<td>Vector Labs</td>
			<td>PK-4001</td>
			<td></td>
		</tr>
		<tr>
			<td>X-gal</td>
			<td>Promega</td>
			<td>V3941</td>
			<td></td>
		</tr>
		<tr>
			<td>X-gal fixative</td>
			<td>*</td>
			<td>*</td>
			<td>2% formaldehyde, 0.1% glutaraldehyde in 1xPBS</td>
		</tr>
		<tr>
			<td>X-gal stain</td>
			<td>*</td>
			<td>*</td>
			<td>X-gal stain; 200ul X-gal (A) in 50ml solution B (0.214g MgCl2, 0.48g K-ferricyanide, 0.734g K-ferrocyanide in 500ml PBS).&#160; Solution B can be made up oin advance and stored at 4&#176;C</td>
		</tr>
		<tr>
			<td>Xylene</td>
			<td>Fisher Scientific</td>
			<td>X/0200/21</td>
			<td></td>
		</tr>
	</tbody>
</table>

protocols for analyzing the role of paneth cells in regenerating the murine intestine using conditional cre-lox mouse models

La superficie epitelial del intestino de mamífero es un tejido dinámico que se renueva cada 3 - 7 días. La comprensión de este proceso de renovación identificó una población de ciclos rápidos células madre intestinales (ISC) que se caracterizan por su expresión del gen LGR5. Estos son apoyados por una población de células madre en reposo, marcado por Bmi-1 de expresión, capaz de sustituirlos en caso de lesión. La investigación de las interacciones entre estas poblaciones es crucial para entender su papel en la enfermedad y el cáncer. Los ISC existen dentro de las criptas en la superficie intestinal, estos nichos apoyan el ISC en la reposición de los epitelios. La interacción entre el ISC y recidivantes probable involucra otras células diferenciadas dentro del nicho, ya que previamente se ha demostrado que la &#39;&#39; troncalidad &#39;&#39; del LGR5 ISC está estrechamente ligada a la presencia de sus células de Paneth vecinos. Usando condicional ratón cre-loxmodelos que probamos el efecto de la supresión de la mayoría de los CSI activos en la presencia o ausencia de las células de Paneth. Aquí se describen las técnicas y análisis realizados para caracterizar el intestino y demuestran que las células de Paneth juegan un papel crucial en el nicho de ISC en ayudar a la recuperación tras el insulto sustancial.

Watch this Scientific Journal Video about Protocols for Analyzing the Role of Paneth Cells in Regenerating the Murine Intestine using Conditional Cre-lox Mouse Models at JoVE.com

Protocols for Analyzing the Role of Paneth Cells in Regenerating the Murine Intestine using Conditional Cre-lox Mouse Models

Las células madre epiteliales intestinales (ISCS) se entremezclan con las células de Paneth. Estas células se diferencian progenie del ISC, que apoyan el ISC y proporcionar protección antibacteriana. Aquí se demuestra la forma en que utilizamos modelos de ratones transgénicos condicionales para establecer que las células de Paneth juegan un papel crucial en el mantenimiento de los epitelios intestinales.

Los protocolos para analizar el papel de las células de Paneth en Regeneración del Murino Intestino utilizando condicional<em&gt; Cre-lox</em&gt; Ratón Modelos

The epithelial surface of the mammalian intestine is a dynamic tissue that renews every 3 - 7 days. Understanding this renewal process identified a ...

protocols-for-analyzing-role-paneth-cells-regenerating-murine

Research

JoVE Journal

Developmental Biology

Protocols for Analyzing the Role of Paneth Cells in Regenerating the Murine Intestine using Conditional Cre-lox Mouse Models

17.5K vistas.  Cardiff University.  Las células madre epiteliales intestinales (ISCS) se entremezclan con las células de Paneth. Estas células se diferencian progenie del ISC, que apoyan el ISC y proporcionar protección antibacteriana. Aquí se demuestra la forma en que utilizamos modelos de ratones transgénicos condicionales para establecer que las células de Paneth juegan un papel crucial en el mantenimiento de los epitelios intestinales. 

Video: Protocols for Analyzing the Role of Paneth Cells in Regenerating the Murine Intestine using Conditional Cre-lox Mouse Models

The Production of Pluripotent Stem Cells from Mouse Amniotic Fluid Cells Using a Transposon System

Induced pluripotent stem (iPS) cells are generated from mouse and human somatic cells by forced expression of defined transcription factors using different methods. Here, we produced iPS cells from mouse amniotic fluid cells, using a non-viral-based transposon system. All obtained iPS cell lines exhibited characteristics of pluripotent cells, including the ability to differentiate toward derivatives of all three germ layers in vitro and in vivo. This strategy opens up the possibility of using cells from diseased fetuses to develop new therapies for birth defects.

In this study, we generate induced pluripotent stem cells from mouse amniotic fluid cells, using a non-viral-based transposon system.

La producción de células madre pluripotentes a partir de células de ratón amniótico líquido mediante un sistema de transposón

Induced pluripotent stem (iPS) cells are generated from mouse and human somatic cells by forced expression of defined transcription factors using ...

Investigación

Biología del Desarrollo

In Vitro Growth of Mouse Preantral Follicles Under Simulated Microgravity

14 day-old mouse ovarian tissue and preantral follicles isolated from same-aged mice were incubated in a simulated microgravity culture system. We quantitatively assessed follicle survival, measured follicle and oocyte diameters, and examined ultrastructure of the oocytes produced from the system. We observed decreased follicle survival, downregulation of expressions of proliferating cell nuclear antigen and growth differentiation factor 9, as indicators for the development of granulosa cells and oocytes, respectively, and oocyte ultrastructural abnormalities under the simulated microgravity condition. The simulated microgravity experimental setup needs to be optimized to provide a model for investigation of the mechanisms involved in the oocyte/follicle in vitro development.

In Vitro Growth of Mouse Preantral Follicles Under Simulated Microgravity

A highly promising technique to generate tissue constructs without using matrix is to culture cells in a simulated microgravity condition. Using a rotary culture system, we examined ovarian follicle growth and oocyte maturation in terms of follicle survival, morphology, growth, and oocyte function under the simulated microgravity condition.

In Vitro Crecimiento de los folículos Preantral ratón bajo microgravedad simulada

14 day-old mouse ovarian tissue and preantral follicles isolated from same-aged mice were incubated in a simulated microgravity culture system. We ...

Live Imaging of Mouse Secondary Palate Fusion

The fusion of the secondary palatal shelves to form the intact secondary palate is a key process in mammalian development and its disruption can lead to cleft secondary palate, a common congenital anomaly in humans. Secondary palate fusion has been extensively studied leading to several proposed cellular mechanisms that may mediate this process. However, these studies have been mostly performed on fixed embryonic tissues at progressive timepoints during development or in fixed explant cultures analyzed at static timepoints. Static analysis is limited for the analysis of dynamic morphogenetic processes such a palate fusion and what types of dynamic cellular behaviors mediate palatal fusion is incompletely understood. Here we describe a protocol for live imaging of ex vivo secondary palate fusion in mouse embryos. To examine cellular behaviors of palate fusion, epithelial-specific Keratin14-cre was used to label palate epithelial cells in ROSA26-mTmGflox reporter embryos. To visualize filamentous actin, Lifeact-mRFPruby reporter mice were used. Live imaging of secondary palate fusion was performed by dissecting recently-adhered secondary palatal shelves of embryonic day (E) 14.5 stage embryos and culturing in agarose-containing media on a glass bottom dish to enable imaging with an inverted confocal microscope. Using this method, we have detected a variety of novel cellular behaviors during secondary palate fusion. An appreciation of how distinct cell behaviors are coordinated in space and time greatly contributes to our understanding of this dynamic morphogenetic process. This protocol can be applied to mutant mouse lines, or cultures treated with pharmacological inhibitors to further advance understanding of how secondary palate fusion is controlled.

Here, we present a protocol for live imaging of mouse secondary palate fusion using confocal microscopy. This protocol can be used in combination with a variety of fluorescent reporter mouse lines, and with pathway inhibitors for mechanistic insight. This protocol can be adapted for live imaging in other developmental systems.

Imágenes en vivo de la fusión secundaria del paladar del ratón

The fusion of the secondary palatal shelves to form the intact secondary palate is a key process in mammalian development and its disruption can lead to ...

A RANKL-based Osteoclast Culture Assay of Mouse Bone Marrow to Investigate the Role of mTORC1 in Osteoclast Formation

Osteoclasts are unique bone-resorbing cells that differentiate from the monocyte/macrophage lineage of bone marrow. Dysfunction of osteoclasts may result in a series of bone metabolic diseases, including osteoporosis. To develop pharmaceutical targets for the prevention of pathological bone mass loss, the mechanisms by which osteoclasts differentiate from precursors must be understood. The ability to isolate and culture a large number of osteoclasts in vitro is critical in order to determine the role of specific genes in osteoclast differentiation. Inactivation of the mammalian/mechanistic target of rapamycin complex 1 (TORC1) in osteoclasts can decrease osteoclast number and increase bone mass; however, the underlying mechanisms require further study. In the present study, a RANKL-based protocol to isolate and culture osteoclasts from mouse bone marrow and to study the influence of mTORC1 inactivation on osteoclast formation is described. This protocol successfully resulted in a large number of giant osteoclasts, typically within one week. Deletion of Raptor impaired osteoclast formation and decreased the activity of secretory tartrate-resistant acid phosphatase, indicating that mTORC1 is critical for osteoclast formation.

This manuscript describes a protocol to isolate and culture osteoclasts in vitro from mouse bone marrow, and to study the role of the mammalian/mechanistic target of rapamycin complex 1 in osteoclast formation.

Una base de RANKL osteoclasto cultura ensayo de médula ósea de ratón para investigar el papel de mTORC1 en la formación de osteoclastos

Osteoclasts are unique bone-resorbing cells that differentiate from the monocyte/macrophage lineage of bone marrow. Dysfunction of osteoclasts may result ...

Application of RNAi and Heat-shock-induced Transcription Factor Expression to Reprogram Germ Cells to Neurons in C. elegans

Studying the cell biological processes during converting the identities of specific cell types provides important insights into mechanism that maintain and protect cellular identities. The conversion of germ cells into specific neurons in the nematode Caenorhabditis elegans (C. elegans) is a powerful tool for performing genetic screens in order to dissect regulatory pathways that safeguard established cell identities. Reprogramming of germ cells to a specific type of neurons termed ASE requires transgenic animals that allow broad over-expression of the Zn-finger transcription factor (TF) CHE-1. Endogenous CHE-1 is expressed exclusively in two head neurons and is required to specify the glutamatergic ASE neurons fate, which can easily be visualized by the gcy-5prom::gfp reporter. A trans gene containing the heat-shock promoter-driven che-1 gene expression construct allows broad mis-expression of CHE-1 in the entire animal upon heat-shock treatment. The combination of RNAi against the chromatin-regulating factor LIN-53 and heat-shock-induced che-1 over-expression leads to reprogramming of germ cell into ASE neuron-like cells. We describe here the specific RNAi procedure and appropriate conditions for heat-shock treatment of transgenic animals in order to successfully induce germ cell to neuron conversion.

Application of RNAi and Heat-shock-induced Transcription Factor Expression to Reprogram Germ Cells to Neurons in C. elegans

This protocol describes how to study cellular processes during cell fate conversion in Caenorhabditis elegans in vivo. Using transgenic animals, allowing heat-shock promoter-driven overexpression of the neuron fate-inducing transcription factor CHE-1 and RNAi-mediated depletion of the chromatin-regulating factor LIN-53 germ cell to neuron reprogramming can be observed in vivo.

Aplicación de RNAi y expresión del Factor de transcripción inducida por choque térmico para reprogramar las células de germen para las neuronas en C. elegans

Studying the cell biological processes during converting the identities of specific cell types provides important insights into mechanism that maintain ...

Assessing Lysosomal Alkalinization in the Intestine of Live Caenorhabditis elegans

The nematode Caenorhabditis elegans (C. elegans) is a model system that is widely used to study longevity and developmental pathways. Such studies are facilitated by the transparency of the animal, the ability to do forward and reverse genetic assays, the relative ease of generating fluorescently labeled proteins, and the use of fluorescent dyes that can either be microinjected into the early embryo or incorporated into its food (E. coli strain OP50) to label cellular organelles (e.g. 9-diethylamino-5H-benzo(a)phenoxazine-5-one and (3-{2-[(1H,1&#39;H-2,2&#39;-bipyrrol-5-yl-kappaN(1))methylidene]-2H-pyrrol-5-yl-kappaN}-N-[2-(dimethylamino)ethyl]propanamidato)(difluoro)boron). Here, we present the use of a fluorescent pH-sensitive dye that stains intestinal lysosomes, providing a visual readout of dynamic, physiological changes in lysosomal acidity in live worms. This protocol does not measure lysosomal pH, but rather aims to establish a reliable method of assessing physiological relevant variations in lysosomal acidity. cDCFDA is a cell-permeant compound that is converted to the fluorescent fluorophore 5-(and-6)-carboxy-2&#39;,7&#39;-dichlorofluorescein (cDCF) upon hydrolysis by intracellular esterases. Protonation inside lysosomes traps cDCF in these organelles, where it accumulates. Due to its low pKa of 4.8, this dye has been used as a pH sensor in yeast. Here we describe the use of cDCFDA as a food supplement to assess the acidity of intestinal lysosomes in C. elegans. This technique allows for the detection of alkalinizing lysosomes in live animals, and has a broad range of experimental applications including studies on aging, autophagy, and lysosomal biogenesis.

Assessing Lysosomal Alkalinization in the Intestine of Live Caenorhabditis elegans

A step-by-step guide to probe loss of lysosomal acidity in the intestine of C. elegans using the pH-sensitive vital dye 5(6)-carboxy-2&#39;,7&#39;-dichlorofluorescein diacetate (cDCFDA)

Evaluación de alcalinización Lysosomal en el intestino de vivir Caenorhabditis elegans

The nematode Caenorhabditis elegans (C. elegans) is a model system that is widely used to study longevity and developmental pathways. Such studies are ...

Computational Analysis of the Caenorhabditis elegans Germline to Study the Distribution of Nuclei, Proteins, and the Cytoskeleton

The Caenorhabditis elegans (C. elegans) germline is used to study several biologically important processes including stem cell development, apoptosis, and chromosome dynamics. While the germline is an excellent model, the analysis is often two dimensional due to the time and labor required for three-dimensional analysis. Major readouts in such studies are the number/position of nuclei and protein distribution within the germline. Here, we present a method to perform automated analysis of the germline using confocal microscopy and computational approaches to determine the number and position of nuclei in each region of the germline. Our method also analyzes germline protein distribution that enables the three-dimensional examination of protein expression in different genetic backgrounds. Further, our study shows variations in cytoskeletal architecture in distinct regions of the germline that may accommodate specific spatial developmental requirements. Finally, our method enables automated counting of the sperm in the spermatheca of each germline. Taken together, our method enables rapid and reproducible phenotypic analysis of the C. elegans germline.

Computational Analysis of the Caenorhabditis elegans Germline to Study the Distribution of Nuclei, Proteins, and the Cytoskeleton

We present an automated method for three-dimensional reconstruction of the Caenorhabditis elegans germline. Our method determines the number and position of each nucleus within the germline and analyses germline protein distribution and cytoskeletal structure.

Análisis computacional de lo elegans de Caenorhabditis del Germline para estudiar la distribución de núcleos, proteínas y citoesqueleto

The Caenorhabditis elegans (C. elegans) germline is used to study several biologically important processes including stem cell development, apoptosis, and ...

Visualizing the Node and Notochordal Plate In Gastrulating Mouse Embryos Using Scanning Electron Microscopy and Whole Mount Immunofluorescence

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is the formation of the transient organizers, the node and notochordal plate, from cells that have passed through the primitive streak. The proper formation of these signaling centers is essential for the development of the body plan and techniques to visualize them are of high interest to mouse developmental biologists. The node and notochordal plate lie on the ventral surface of gastrulating mouse embryos around embryonic day (E) 7.5 of development. The node is a cup-shaped structure whose cells possess a single slender cilium each. The proper subcellular localization and rotation of the cilia in the node pit determines left-right asymmetry. The notochordal plate cells also possess single cilia albeit shorter than those of the node cells. The notochordal plate forms the notochord which acts as an important signaling organizer for somitogenesis and neural patterning. Because the cells of the node and notochordal plate are transiently present on the surface and possess cilia, they can be visualized using scanning electron microscopy (SEM). Among other techniques used to visualize these structures at the cellular level is whole mount immunofluorescence (WMIF) using the antibodies against the proteins that are highly expressed in the node and notochordal plate. In this report, we describe our optimized protocols to perform SEM and WMIF of the node and notochordal plate in developing mouse embryos to help in the assessment of tissue shape and cellular organization in wild-type and gastrulation mutant embryos.

The node and notochordal plate are transient signaling organizers in developing mouse embryos that can be visualized using several techniques. Here, we describe in detail how to perform two of the techniques to study their structure and morphogenesis: 1) scanning electron microscopy (SEM); and 2) whole mount immunofluorescence (WMIF).

Visualización de la placa notocordal en embriones de ratón Gastrulating con microscopía electrónica e inmunofluorescencia de Monte todo y nodo

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is ...

Adult Zebrafish Injury Models to Study the Effects of Prednisolone in Regenerating Bone Tissue

Zebrafish are able to regenerate various organs, including appendages (fins) after amputation. This involves the regeneration of bone, which regrows within roughly two weeks after injury. Furthermore, zebrafish are able to heal bone rapidly after trepanation of the skull, and repair fractures that can be easily introduced into zebrafish bony fin rays. These injury assays represent feasible experimental paradigms to test the effect of administered drugs on rapidly forming bone. Here, we describe the use of these 3 injury models and their combined use with systemic glucocorticoid treatment, which exerts bone inhibitory and immunosuppressive effects. We provide a workflow on how to prepare for immunosuppressive treatment in adult zebrafish, illustrate how to perform fin amputation, trepanation of calvarial bones, and fin fractures, and describe how the use of glucocorticoids affects both bone forming osteoblasts and cells of the monocyte/macrophage lineage as part of innate immunity in bone tissue.

Here, we describe 3 adult zebrafish injury models and their combined use with immunosuppressive drug treatment. We provide guidance on imaging of regenerating tissues and on detecting bone mineralization therein.

Pez cebra adulto lesión modelos para estudiar los efectos de la prednisolona en regeneración de tejido óseo

Zebrafish are able to regenerate various organs, including appendages (fins) after amputation. This involves the regeneration of bone, which regrows ...

Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C (UV-C) Damage

The ocular surface is subjected to regular wear and tear due to various environmental factors. Exposure to UV-C radiation constitutes an occupational health hazard. Here, we demonstrate the exposure of primary stem cells from the mouse ocular surface to UV-C radiation. Reactive oxygen species (ROS) formation is the readout of the extent of oxidative stress/damage. In an experimental in vitro setting, it is also essential to assess the percentage of dead cells generated due to oxidative stress. In this article, we will demonstrate the 2&#39;,7&#39;-Dichlorofluoresceindiacetate (DCFDA) staining of UV-C exposed mouse primary ocular surface stem cells and their quantification based on the fluorescent images of DCFDA staining. DCFDA staining directly corresponds to ROS generation. We also demonstrate the quantification of dead and live cells by simultaneous staining with propidium iodide (PI) and Hoechst 3332 respectively and the percentage of DCFDA (ROS positive) and PI positive cells.

Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C UV-C Damage

This protocol demonstrates the simultaneous detection of reactive oxygen species (ROS), live cells, and dead cells in live primary cultures from mouse ocular surface cells. 2&#39;,7&#39;-Dichlorofluoresceindiacetate, propidium iodide, and Hoechst staining are used to assess the ROS, dead cells, and live cells, respectively, followed by imaging and analysis.

Evaluación del daño oxidativo en las células madre primarias del ratón/células madre en respuesta al daño ultravioleta-C (UV-C)

The ocular surface is subjected to regular wear and tear due to various environmental factors. Exposure to UV-C radiation constitutes an occupational ...