Estos estudios se han apoyado en parte por la financiación de los NIH R01 AI36532 para GAH. Nos gustaría agradecer el apoyo sobresaliente en el trasplante de la patología del Dr. Tibor Nadasdy, y la valiosa orientación y visión de futuro previstas por el fallecido Dr. Carlos G. Orosz en el inicio de este esfuerzo de investigación.

Donantes de órganos de cosecha (2): <ol><li> Anestesiar a los donantes con IP 65mg/kg pentobarbital, la anestesia se mantiene por isoflurano (2.3%). </li><li> Haga una incisión desde el esternón hasta el pubis para entrar en el abdomen de los donantes y exponer el riñón izquierdo, moviendo el intestino lateralmente hacia el lado derecho. </li><li> Aislar el riñón izquierdo por ligar y dividir los vasos suprarrenales y los testículos con una sutura de seda 8-0. </li><li> Movilizar a la aorta por encima de su unión con la arteria y la vena renal. </li><li> Movilizar a la vena cava inferior (VCI) por encima y por debajo de su unión con la arteria y la vena renal. </li><li> Ligar la aorta por debajo de la arteria y vena renal con una sutura de seda 8-0 para minimizar el sangrado. </li><li> Disecar el uréter izquierdo desde el hilio renal hasta la vejiga. </li><li> Exponer la unión ureterovesical con retracción caudal en el domo de la vejiga. </li><li> Los impuestos especiales un pequeño parche, elíptica de la vejiga que contiene la unión ureterovesical izquierda, que se utiliza para la reconstrucción urinaria a través de una anastomosis de la vejiga de la vejiga. El uréter derecho no está incluido en la vejiga. </li><li> Ligar la vena cava inferior por debajo de la arteria y vena renal con una sutura de seda 8-0. </li><li> Ligar la aorta por encima de la arteria y vena renal, y poco a poco perfusión del injerto in situ con 0,4 ml de 0,2 frío, heparinizada solución de Ringer lactato a través de la aorta infrarrenal. </li><li> Ligar la vena cava inferior por encima de la arteria y vena renal con una sutura de seda 8-0. </li><li> Transecto de la vena renal en su unión con la vena cava inferior. </li><li> Divide la aorta oblicuamente, de aproximadamente 2 mm por debajo de la arteria renal. </li><li> Extraer el riñón y su aporte vascular con uréter unido a la revisión de la vejiga en bloque. Tienda en solución de Ringer lactato en el hielo. </li><li> La eutanasia de los donantes del ratón por dislocación cervical bajo anestesia. </li></ol> Receptor Trasplante (2): <ol><li> Anestesiar al destinatario con 65 mg / kg de pentobarbital IP y mantener la anestesia por isoflurano (2.3%). </li><li> Hacer una incisión, la cubierta del intestino con una gasa húmeda y con cuidado retirar a la izquierda. </li><li> Ligar el uréter derecho, la arteria y la vena renal, y quitar el riñón derecho. </li><li> Con cuidado, aislar y cruz de pinza de la aorta infrarrenal y vena cava inferior con dos pinzas de 4 mm microvasular después de la ligadura de las ramas lumbar. </li><li> Colocar una sutura de nylon 10-0 a través de un espesor total de la aorta y se retraen de hacer una aortaotomy elíptica de un solo corte (aproximadamente una quinta parte del diámetro del vaso). </li><li> Hacer una venotomía longitudinal por la perforación de la vena cava inferior con una aguja de calibre 30 y se extienden adecuadamente utilizando micro tijeras. </li><li> Riego de la aorta y vena cava inferior con solución salina heparinizada para limpiar la sangre intraluminal o coágulos. </li><li> Extirpar el riñón de donantes del hielo y colocarlo dentro del abdomen en el costado derecho del ratón. El riñón del donante se mantiene húmedo con una gasa empapada en solución salina fría. </li><li> Coloque dos suturas en el vértice proximal y distal de la aortaotomy los beneficiarios con el manguito de los donantes de aorta. </li><li> Hacer una anastomosis término-lateral entre el manguito aórtica donantes y la pared anterior de la aortaotomy destinatarios, con 2 o 3 continua 10-0 de nylon en el exterior de la aorta. </li><li> A su vez el injerto renal de donante a la banda izquierda del destinatario. repita el procedimiento anterior entre el manguito de la aorta de los donantes y la pared posterior de la aortaotomy destinatarios </li><li> Realizar una anastomosis término-lateral entre la vena renal de donante y la pared posterior de la VCI destinatarios, con 4 a 5 continua 10-0 de nylon en el interior de la vena cava inferior. y luego la pared anterior de la vena renal IVC y los donantes se cierran con 4 ~ 5 puntos de sutura continua fuera de la vena cava inferior. </li><li> La anastomosis de la vena y la arteria tanto debe ser terminado en 20 minutos. </li><li> Enjuague el injerto con solución salina fría veces varias durante la anastomosis. </li><li> Divide la cúpula de la vejiga receptor, y detener la hemorragia con cauterización. </li><li> Haz un pequeño corte en la cúpula. </li><li> Coloque dos suturas de nylon 10-0 para anastomize el parche donantes vejiga pequeña con la cúpula de la vejiga destinatarios. Cada lado de la anastomosis se sutura con 8 ~ 10 puntos de sutura continua. </li><li> Cerrar el abdomen en dos capas con continuas 4-0 estéril, sintético absorbible Vicryl. </li><li> Dar a los ratones receptores 0,4 ml de solución salina caliente durante la operación de inyección IV intermitente. </li></ol> Cuidados post-operatorios del destinatario <ol><li> Después de cerrar el abdomen, una sola inyección intramuscular de penicilina (500U/10g) se administra (2). </li><li> Además, los beneficiarios reciben 0,05 mg / kg por vía intramuscular la buprenorfina en el día 0 y 1 día después de la cirugía para el dolor. Después de la cirugía, los receptores de trasplante recibir el agua que contiene Sulfatrim (100mg/kg) hasta que el experimento se terminated. </li><li> Para las primeras 24 horas después de la operación los ratones se mantienen en una incubadora con temperatura controlada. </li><li> Los ratones se recuperan de la anestesia antes de 1 hora de la operación y se les da la comida regular y agua ad libitum. </li><li> Suturas de la piel se retiró 2 semanas después de la cirugía. </li></ol> Receptor nefrectomía <ol><li> Anestesiar el receptor 4 ~ 7 días después del trasplante renal con 65 mg / kg IP pentobarbital, la anestesia se mantiene con isoflurano (2.3%). </li><li> Abra el abdomen mediante una incisión de línea media. </li><li> Cubrir el intestino con una gasa empapada en solución salina y con cuidado retirar a la derecha. </li><li> Extirpar el riñón izquierdo después de la ligadura de la vena del uréter izquierdo, el riñón y la arteria. </li><li> Cerrar el abdomen en dos capas con continuas 4-0 sintético absorbible Vicryl. </li></ol> Las mediciones de creatinina en sangre entera <ol><li> Semanales para la extracción de sangre cada dos semanas de menos de 0,2 cc se lleva a cabo ya sea submandibularly sin anestesia o retro orbital, bajo anestesia con isoflurano. </li><li> Cuantitativa los niveles de creatinina en la sangre entera se determinó utilizando un analizador de i-STAT Portable Clínica (Heska Corp., Fort Collins, CO). </li><li> Unidades convencionales (mg / dl) se convierten a las unidades de mol / L, multiplicando las unidades convencionales de 88,4. </li></ol>

<ol>
	<li>Russell, P. S., Chase, C. M., Colvin, R. B., Plate, J. M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kidney+transplants+in+mice.+An+analysis+of+the+immune+status+of+mice+bearing+long-term,+H-2+incompatible+transplants.">Kidney transplants in mice. An analysis of the immune status of mice bearing long-term, H-2 incompatible transplants.</a> JExpMed. 147, 1449-1468 (1978).</li><li>Zhang, Z., Schlachta, C., Duff, J., Stiller, C., Grant, D., Zhong, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+techniques+for+kidney+transplantation+in+mice.">Improved techniques for kidney transplantation in mice.</a> Microsurgery. 16 (2), 103-109 (1995).</li></ol>

Los experimentos con animales se realizaron de acuerdo con las directrices y normas establecidas por la Universidad Estatal de Ohio IACUC.

Hemos llevado a cabo aproximadamente 1200 casos de trasplante renal en ratones con una tasa de éxito técnico de&gt; 90%. En comparación con el trasplante de corazón, la tasa de éxito del trasplante renal es generalmente baja. Sin embargo, nuestro laboratorio ha mantenido una alta tasa de éxito (&gt; 90%) de un trasplante de riñón. Los puntos clave para el éxito son la reducción de las lesiones de reperfusión en los riñones de donantes y receptores de ambos, y minimizar la hemorragia y trombosis durante todo ...

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<tr>
<td>i-STAT</td>
<td>Other</td>
<td>HESKA</td>
<td>Cat 5101</td>
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<td>i-STAT Cartridge</td>
<td>Other</td>
<td>HESKA</td>
<td>CAT 5110-CREA</td>
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<td>Sulfatrim</td>
<td>Other</td>
<td>Actavis</td>
<td>R02109</td>
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<td>Other</td>
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murine renal transplantation procedure

El trasplante renal ortotópico en ratones es un procedimiento técnicamente difícil. Aunque los trasplantes de riñón por primera vez en los ratones fueron realizados por Russell et al más de 30 años (1) y refinado por Zhang et al año más tarde (2), muy pocas personas en el mundo han llegado a dominar este procedimiento. En nuestro laboratorio se han realizado con éxito trasplantes de riñón ortotópico de 1200 con una tasa de&gt; supervivencia del 90%. Los puntos clave para el éxito incluyen un estricto control de la reperfusión, hemorragia y trombosis, tanto durante el procedimiento y después del trasplante, y el uso de 10-0 en lugar de 11-0 sutura de la anastomosis. Cuidados post-operatorios y tratamiento del receptor es extremadamente importante para el éxito del trasplante y la evaluación. Todos los receptores de injerto renal recibir antibióticos en forma de una inyección de penicilina inmediatamente después del trasplante y Sulfatrim en el agua potable continuamente. Salud de los animales en general se evalúa a diario y todo análisis de creatinina en la sangre se llevan a cabo habitualmente con un portátil I-STAT máquina para evaluar la función del injerto.

Watch this Scientific Journal Video about Murine Renal Transplantation Procedure at JoVE.com

Murine Renal Transplantation Procedure

El trasplante renal en ratones es un procedimiento técnicamente difícil que requiere una cuidadosa atención post-operatoria y el tratamiento para el éxito.

Procedimiento murino Trasplante Renal

Renal orthotopic transplantation in mice is a technically challenging procedure. Although the first kidney transplants in mice were performed by Russell ...

Research

JoVE Journal

Biology

29.6K vistas.  The Ohio State University. El trasplante renal en ratones es un procedimiento técnicamente difícil que requiere una cuidadosa atención post-operatoria y el tratamiento para el éxito.

Video: Murine Renal Transplantation Procedure

Heterotopic Heart Transplantation in Mice

The mouse heterotopic heart transplantation has been used widely since it was introduced by Drs. Corry and Russell in 1973. It is particularly valuable for studying rejection and immune response now that newer transgenic and gene knockout mice are available, and a large number of immunologic reagents have been developed. The heart transplant model is less stringent than the skin transplant models, although technically more challenging. We have developed a modified technique and have completed over 1000 successful cases of heterotopic heart transplantation in mice. When making anastomosis of the ascending aorta and abdominal aorta, two stay sutures are placed at the proximal and distal apexes of recipient abdominal aorta with the donor s ascending aorta, then using 11-0 suture for anastomosis on both side of aorta with continuing sutures. The stay sutures make the anastomosis easier and 11-0 is an ideal suture size to avoid bleeding and thrombosis.
When making anastomosis of pulmonary artery and inferior vena cava, two stay sutures are made at the proximal apex and distal apex of the recipient s inferior vena cava with the donor s pulmonary artery. The left wall of the inferior vena cava and donor s pulmonary artery is closed with continuing sutures in the inside of the inferior vena cava after, one knot with the proximal apex stay suture the right wall of the inferior vena cava and the donor s pulmonary artery are closed with continuing sutures outside the inferior vena cave with 10-0 sutures. This method is easier to perform because anastomosis is made just on the one side of the inferior vena cava and 10-0 sutures is the right size to avoid bleeding and thrombosis. In this article, we provide details of the technique to supplement the video.

The mouse heterotopic heart transplantation model has been proven by many investigators to be an important method for studying mechanisms of rejection and immune response. However, the techniques involved are still challenging. By modifying standard techniques we have had success with more than 1000 transplants.

El trasplante cardíaco heterotópico en ratones

The mouse heterotopic heart transplantation has been used widely since it was introduced by Drs. Corry and Russell in 1973. It is particularly valuable ...

Investigación

Biología

Small Bowel Transplantation In Mice

Since 1990, the development of tacrolimus-based immunosuppression and improved surgical techniques, the increased array of potent immunosuppressive medications, infection prophylaxis, and suitable patient selection helped improve actuarial graft and patient survival rates for all types of intestine transplantation. Patients with irreversible intestinal failure and complications of parenteral nutrition should now be routinely considered for small intestine transplantation. However, Survival rates for small intestinal transplantation have been slow to improve compares increasingly favorably with renal, liver, heart and lung. The small bowel transplantation is still unsatisfactory compared with other organs. Further progress may depend on better understanding of immunology and physiology of the graft and can be greatly facilitated by animal models. A wider use of mouse small bowel transplantation model is needed in the study of immunology and physiology of the transplantation gut as well as efficient methods in diagnosing early rejection. However, this model is limited to use because the techniques involved is an extremely technically challenging. We have developed a modified technique. When making anastomosis of portal vein and inferior vena cava, two stay sutures are made at the proximal apex and distal apex of the recipient s inferior vena cava with the donor s portal vein. The left wall of the inferior vena cava and donor s portal vein is closed with continuing sutures in the inside of the inferior vena cava after, after one knot with the proximal apex stay suture the right wall of the inferior vena cava and the donor s portal vein are closed with continuing sutures outside the inferior vena cave with 10-0 sutures. This method is easier to perform because anastomosis is made just on the one side of the inferior vena cava and 10-0 sutures is the right size to avoid bleeding and thrombosis.  In this article, we provide details of the technique to supplement the video.

The mouse small bowel transplantation model has been recognized as an important tool to study mechanismes of immune rejection and screen new immunosuppressive drugs. However, this model is limited to use because the techniques involved is an extremely technically challenge. Now we introduce the modified technique.

Trasplante de intestino delgado en ratones

Since 1990, the development of tacrolimus-based immunosuppression and improved surgical techniques, the increased array of potent immunosuppressive ...

Murine Skin Transplantation

As one of the most stringent and least technically challenging models, skin transplantation is a standard method to assay host T cell responses to MHC-disparate donor antigens. The aim of this video-article is to provide the viewer with a step-by-step visual demonstration of skin transplantation using the mouse model. The protocol is divided into 5 main components: 1) harvesting donor skin; 2) preparing recipient for transplant; 3) skin transplant; 4) bandage removal and monitoring graft rejection; 5) helpful hints. Once proficient, the procedure itself should take &lt;10 min to perform.

Allogeneic skin transplantation is a standard model to assay host T cell responses to MHC-disparate donor antigens. This video-article provides a visual tutorial of each step involved in performing a BALB/c--&gt;C57BL/6 skin transplant.

Trasplante de piel murina

As one of the most stringent and least technically challenging models, skin transplantation is a standard method to assay host T cell responses to ...

Generation of Human CD40-activated B cells

CD40-activated B cells (CD40-B cells) have been identified as an alternative source of immuno-stimulatory antigen-presenting cells (APC) for cancer immunotherapy 1-3. Compared to Dendritic cells (DCs), the best characterized APC, CD40-B cells have several distinct biological and technical properties. Similar to DCs, B cells show an increased expression of MHC and co-stimulatory molecules (Fig.1b), exhibit a strong migratory capacity and present antigen presentation efficiently to T cells, after stimulation with interleukin-4 and CD40 ligand (CD40L). However, in contrast to immature or mature DCs, CD40-B cells express the full lymph node homing triad consisting of CD62L, CCR7/CXCR4, and leukocyte function antigen-1 (LFA1, CD11a/CD18), necessary for homing to secondary lymphoid organs (Fig.1a) 3. CD40-B cells can be generated without difficulties from very small amounts of peripheral blood which can be further expanded in vitro to very large amounts of highly-pure CD40-B cells (&gt;109 cells per patient) from healthy donors as well as cancer patients (Fig.1c,d) 1,4. 
In this protocol we demonstrate how to obtain fully activated CD40-B cells from human PBMC. Key molecules for the cell culture are CD40 ligand, interleukin-4 (IL-4) and cyclosporin A (CsA), which are replenished in a 3-4 day culture cycle. For laboratory purposes CD40-stimulation is provided by NIH/3T3 cells expressing recombinant human CD40 ligand (tCD40L NIH/3T3) 5. To avoid contamination with non-transfected cells, expression of the human CD40 ligand on the transfectants has to be checked regularly (Fig.2). 
After 14 days CD40-B cell cultures consist of more than 95% pure B cells and an expansion of CD40-B cells over 65 days is frequently possible without any loss of function 1, 4. CD40-B cells efficiently take up, process and present antigens to T cells 6. They do not only prime na&#970;ve, but also expand memory T cells 7,8. CD40-activated B cells can be used to study B-cell activation, differentiation and function. Moreover, they represent a promising tool for therapeutic or preventive vaccination against tumors 9.

In this video we present the ex vivo generation and expansion of human CD40-activated B cells (CD40-B) from peripheral blood mononuclear cells (PBMC) by stimulation with CD40 ligand and interleukin-4.

Generación de humanos CD40 activado por células B

CD40-activated B cells (CD40-B cells) have been identified as an alternative source of immuno-stimulatory antigen-presenting cells (APC) for cancer ...

Generating Chimeric Zebrafish Embryos by Transplantation

One of the most powerful tools used to gain insight into complex developmental processes is the analysis of chimeric embryos. A chimera is defined as an organism that contains cells from more than one animal; mosaics are one type of chimera in which cells from more than one genotype are mixed, usually wild-type and mutant. In the zebrafish, chimeras can be readily made by transplantation of cells from a donor embryo into a host embryo at the appropriate embryonic stage. Labeled donor cells are generated by injection of a lineage marker, such as a fluorescent dye, into the one-cell stage embryo. Labeled donor cells are removed from donor embryos and introduced into unlabeled host embryos using an oil-controlled glass pipette mounted on either a compound or dissecting microscope. Donor cells can in some cases be targeted to a specific region or tissue of the developing blastula or gastrula stage host embryo by choosing a transplantation site in the host embryo based on well-established fate maps.

A step-by-step guide to generating targeted chimeric zebrafish embryos by transplantation at the blastula or gastrula stage.

La generación de embriones quiméricos de pez cebra mediante un trasplante

One of the most powerful tools used to gain insight into complex developmental processes is the analysis of chimeric embryos. A chimera is defined as an ...

Mammary Epithelial Transplant Procedure

This article describes and compares the fat pad clearance procedure developed by DeOme KB et al.1 and the sparing procedure developed by Brill B et al.2, followed by the mammary epithelial transplant procedure. The mammary transplant procedure is widely used by mammary biologists because it takes advantage of the fact that significant development of the mammary epithelium doesn't occur until after puberty. At 3 weeks of age, growth of the mammary epithelial tree is confined to the vicinity of the nipple and the fat pad is largely devoid of mammary epithelium, but by 7 weeks of age the epithelial ductal tree extends throughout the entire fat pad. Therefore, if this small portion of the fat pad containing epithelium, the region between the nipple and the lymph node, is removed at 3 weeks of age, the endogenous epithelium will never populate the mammary fat pad and the fat pad is described as "cleared". At this time, mammary epithelium from another source can be transplanted in the cleared fat pad where it has the potential to extend mammary ductal trees through out the fat pad. This procedure has been utilized in many experimental models including the examination of tumor phenotype in transgenic mammary epithelial tissue without the confounding effects of genotype on the entire animal3, in the identification of mammary stem cells by transplanting cells in limited dilution4,5, determining if hyperplastic nodules proceed to mammary tumors6, and to assess the effect of prior hormone exposure on the behavior of the mammary epithelium7,8.
Three week old host mice are anesthetized, cleaned and restrained on a surgical stage. A mid-sagittal incision is made through the skin, but not the peritoneum, extending from the pubis to the sternum. Oblique cuts are made through the skin from the mid-sagittal incision across the pelvis toward each leg. The skin is pulled away from the peritoneum to expose the 4th inguinal mammary gland. The fat pad is cleared by removing the fat pad tissue anterior to the lymph node. Epithelium fragments or epithelial cells are transplanted into the remaining cleared fat pad and the mouse is closed.

This article demonstrates the procedure developed by DeOme KB et al. (1959) and the sparing procedure developed by Brill B et al. (2008) for clearing the 4th inguinal mammary fat pad of a pubescent mouse in preparation for transplantation of mammary fragments, mammary epithelial cells, or mammary tumor cells.

Procedimiento de mama epiteliales de Trasplantes

This article describes and compares the fat pad clearance procedure developed by DeOme KB et al.1 and the sparing procedure developed by Brill B et al.2, ...

Laser Ablation of the Zebrafish Pronephros to Study Renal Epithelial Regeneration

Acute kidney injury (AKI) is characterized by high mortality rates from deterioration of renal function over a period of hours or days that culminates in renal failure1. AKI can be caused by a number of factors including ischemia, drug-based toxicity, or obstructive injury1. This results in an inability to maintain fluid and electrolyte homeostasis. While AKI has been observed for decades, effective clinical therapies have yet to be developed. Intriguingly, some patients with AKI recover renal functions over time, a mysterious phenomenon that has been only rudimentally characterized1,2. Research using mammalian models of AKI has shown that ischemic or nephrotoxin-injured kidneys experience epithelial cell death in nephron tubules1,2, the functional units of the kidney that are made up of a series of specialized regions (segments) of epithelial cell types3. Within nephrons, epithelial cell death is highest in proximal tubule cells. There is evidence that suggests cell destruction is followed by dedifferentiation, proliferation, and migration of surrounding epithelial cells, which can regenerate the nephron entirely1,2. However, there are many unanswered questions about the mechanisms of renal epithelial regeneration, ranging from the signals that modulate these events to reasons for the wide variation of abilities among humans to regenerate injured kidneys.
The larval zebrafish provides an excellent model to study kidney epithelial regeneration as its pronephric kidney is comprised of nephrons that are conserved with higher vertebrates including mammals4,5. The nephrons of zebrafish larvae can be visualized with fluorescence techniques because of the relative transparency of the young zebrafish6. This provides a unique opportunity to image cell and molecular changes in real-time, in contrast to mammalian models where nephrons are inaccessible because the kidneys are structurally complex systems internalized within the animal. Recent studies have employed the aminoglycoside gentamicin as a toxic causative agent for study of AKI and subsequent renal failure: gentamicin and other antibiotics have been shown to cause AKI in humans, and researchers have formulated methods to use this agent to trigger kidney damage in zebrafish7,8. However, the effects of aminoglycoside toxicity in zebrafish larvae are catastrophic and lethal, which presents a difficulty when studying epithelial regeneration and function over time. Our method presents the use of targeted cell ablation as a novel tool for the study of epithelial injury in zebrafish. Laser ablation gives researchers the ability to induce cell death in a limited population of cells. Varying areas of cells can be targeted based on morphological location, function, or even expression of a particular cellular phenotype. Thus, laser ablation will increase the specificity of what researchers can study, and can be a powerful new approach to shed light on the mechanisms of renal epithelial regeneration. This protocol can be broadly applied to target cell populations in other organs in the zebrafish embryo to study injury and regeneration in any number of contexts of interest.

Acute kidney injury (AKI) in humans is a common clinical problem caused by damage to the epithelial cells that comprise kidney nephrons, and AKI is associated with high mortality rates of 50-70%1. Following epithelial cell destruction, nephrons have a limited ability to regenerate, though the mechanisms and limitations that guide this phenomenon remain poorly understood. In this video article, we describe our technique for targeted laser ablation of kidney nephron cells in the zebrafish embryo kidney, or pronephros. Our new method can be used to complement nephrotoxicity-induced models of AKI and gain a high-resolution understanding of the cell and molecular alterations that are associated with epithelial regeneration in the kidney nephron.

La ablación con láser de la pronefros pez cebra para el Estudio de la regeneración epitelial renal

Acute kidney injury (AKI) is characterized by high mortality rates from deterioration of renal function over a period of hours or days that culminates in ...

Studying Proteolysis of Cyclin B at the Single Cell Level in Whole Cell Populations

Equal distribution of chromosomes between the two daughter cells during cell division is a prerequisite for guaranteeing genetic stability 1. Inaccuracies during chromosome separation are a hallmark of malignancy and associated with progressive disease 2-4. The spindle assembly checkpoint (SAC) is a mitotic surveillance mechanism that holds back cells at metaphase until every single chromosome has established a stable bipolar attachment to the mitotic spindle1. The SAC exerts its function by interference with the activating APC/C subunit Cdc20 to block proteolysis of securin and cyclin B and thus chromosome separation and mitotic exit. Improper attachment of chromosomes prevents silencing of SAC signaling and causes continued inhibition of APC/CCdc20 until the problem is solved to avoid chromosome missegregation, aneuploidy and malignant growths1.
Most studies that addressed the influence of improper chromosomal attachment on APC/C-dependent proteolysis took advantage of spindle disruption using depolymerizing or microtubule-stabilizing drugs to interfere with chromosomal attachment to microtubules. Since interference with microtubule kinetics can affect the transport and localization of critical regulators, these procedures bear a risk of inducing artificial effects 5.
To study how the SAC interferes with APC/C-dependent proteolysis of cyclin B during mitosis in unperturbed cell populations, we established a histone H2-GFP-based system which allowed the simultaneous monitoring of metaphase alignment of mitotic chromosomes and proteolysis of cyclin B 6.
To depict proteolytic profiles, we generated a chimeric cyclin B reporter molecule with a C-terminal SNAP moiety 6 (Figure 1). In a self-labeling reaction, the SNAP-moiety is able to form covalent bonds with alkylguanine-carriers (SNAP substrate) 7,8 (Figure 1). SNAP substrate molecules are readily available and carry a broad spectrum of different fluorochromes. Chimeric cyclin B-SNAP molecules become labeled upon addition of the membrane-permeable SNAP substrate to the growth medium 7 (Figure 1). Following the labeling reaction, the cyclin B-SNAP fluorescence intensity drops in a pulse-chase reaction-like manner and fluorescence intensities reflect levels of cyclin B degradation 6 (Figure 1). Our system facilitates the monitoring of mitotic APC/C-dependent proteolysis in large numbers of cells (or several cell populations) in parallel. Thereby, the system may be a valuable tool to identify agents/small molecules that are able to interfere with proteolytic activity at the metaphase to anaphase transition. Moreover, as synthesis of cyclin B during mitosis has recently been suggested as an important mechanism in fostering a mitotic block in mice and humans by keeping cyclin B expression levels stable 9,10, this system enabled us to analyze cyclin B proteolysis as one element of a balanced equilibrium 6.

Metaphase to anaphase transition is triggered through anaphase-promoting complex (APC/C)-dependent ubiquitination and subsequent destruction of cyclin B. Here, we established a system which, following pulse-chase labeling, allows monitoring cyclin B proteolysis in entire cell populations and facilitates the detection of interference by the mitotic checkpoint.

El estudio de la proteólisis de ciclina B en el nivel de células individuales en poblaciones de células enteras

Equal distribution of chromosomes between the two daughter cells during cell division is a prerequisite for guaranteeing genetic stability 1. Inaccuracies ...

Application of Retinoic Acid to Obtain Osteocytes Cultures from Primary Mouse Osteoblasts

The need for osteocyte cultures is well known to the community of bone researchers; isolation of primary osteocytes is difficult and produces low cell numbers. Therefore, the most widely used cellular system is the osteocyte-like MLO-Y4 cell line.
The method here described refers to the use of retinoic acid to generate a homogeneous population of ramified cells with morphological and molecular osteocyte features.
After isolation of osteoblasts from mouse calvaria, all-trans retinoic acid (ATRA) is added to cell medium, and cell monitoring is conducted daily under an inverted microscope. First morphological changes are detectable after 2 days of treatment and differentiation is generally complete in 5 days, with progressive development of dendrites, loss of the ability to produce extracellular matrix, down-regulation of osteoblast markers and up-regulation of osteocyte-specific molecules.
Daily cell monitoring is needed because of the inherent variability of primary cells, and the protocol can be adapted with minimal variation to cells obtained from different mouse strains and applied to transgenic models. 
The method is easy to perform and does not require special instrumentation, it is highly reproducible, and rapidly generates a mature osteocyte population in complete absence of extracellular matrix, allowing the use of these cells for unlimited biological applications.

Treatment of primary mouse osteoblasts with retinoic acid produces a homogeneous population of ramified cells bearing morphological and molecular features of osteocytes. The method overcomes the difficulty of obtaining and maintaining primary osteocytes in culture, and can be advantageous to study cells derived from transgenic models.&#160;

La aplicación de ácido retinoico para obtener cultivos de osteocitos principal del ratón osteoblastos

The need for osteocyte cultures is well known to the community of bone researchers; isolation of primary osteocytes is difficult and produces low cell ...

Cytosolic Calcium Measurements in Renal Epithelial Cells by Flow Cytometry

A variety of cellular processes, both physiological and pathophysiological, require or are governed by calcium, including exocytosis, mitochondrial function, cell death, cell metabolism and cell migration to name but a few. Cytosolic calcium is normally maintained at low nanomolar concentrations; rather it is found in high micromolar to millimolar concentrations in the endoplasmic reticulum, mitochondrial matrix and the extracellular compartment. Upon stimulation, a transient increase in cytosolic calcium serves to signal downstream events. Detecting changes in cytosolic calcium is normally performed using a live cell imaging set up with calcium binding dyes that exhibit either an increase in fluorescence intensity or a shift in the emission wavelength upon calcium binding. However, a live cell imaging set up is not freely accessible to all researchers. Alternative detection methods have been optimized for immunological cells with flow cytometry and for non-immunological adherent cells with a fluorescence microplate reader. Here, we describe an optimized, simple method for detecting changes in epithelial cells with flow cytometry using a single wavelength calcium binding dye. Adherent renal proximal tubule epithelial cells, which are normally difficult to load with dyes, were loaded with a fluorescent cell permeable calcium binding dye in the presence of probenecid, brought into suspension and calcium signals were monitored before and after addition of thapsigargin, tunicamycin and ionomycin.

Calcium is involved in numerous physiological and pathophysiological signaling pathways. Live cell imaging requires specialized equipment and can be time consuming. A quick, simple method using a flow cytometer to determine relative changes in cytosolic calcium in adherent epithelial cells brought into suspension was optimized.

Las mediciones del calcio citosólico en las células epiteliales renales mediante citometría de flujo

A variety of cellular processes, both physiological and pathophysiological, require or are governed by calcium, including exocytosis, mitochondrial ...