Name: a possible zebrafish model of polycystic kidney disease: knockdown of wnt5a causes cysts in zebrafish kidneys
Uploaded: 2014-12-02T11:00:00
Description: Watch this Scientific Journal Video about A Possible Zebrafish Model of Polycystic Kidney Disease: Knockdown of wnt5a Causes Cysts in Zebrafish Kidneys at JoVE.com

This work was supported by the NIH (DK093625 to L.H., and DK069909 and DK047757 to J.H.L.) and the VA (Merit Award I01BX000820 to J.H.L.). We would like to thank Dr. Michael Pack and Dr. Jie He at the University of Pennsylvania Zebrafish Core for providing essential support.

NOTE: Ethics Statement: All zebrafish experiments were approved by the Institutional Animal Care and Use Committee at the Eastern Virginia Medical School.
1. Morpholino Preparation
<ol>
	<li>Design and synthesize translation-blocking (AUG-) and splice-inhibiting (Splice-) anti-sense morpholino (MO) oligonucleotides for the gene of interest as per manufacturer&#8217;s instructions (Figure&#160;1A). Please see manufacturer&#8217;s information in Table 1. 
	NOTE: MOs are shipp...

<ol>
	<li>Choi, S. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cdc42+deficiency+causes+ciliary+abnormalities+and+cystic+kidneys.">Cdc42 deficiency causes ciliary abnormalities and cystic kidneys.</a> J Am Soc Nephrol. 24 (9), 1435-1450 (2013).</li><li>Hostetter, C. L., Sullivan-Brown, J. L., Burdine, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+pronephros:+a+model+for+understanding+cystic+kidney+disease.">Zebrafish pronephros: a model for understanding cystic kidney disease.</a> Dev Dyn. 228 (3), 514-522 (2003).</li><li>Nyengaard, J. R., Bendtsen, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glomerular+number+and+size+in+relation+to+age,+kidney+weight,+and+body+surface+in+normal+man.">Glomerular number and size in relation to age, kidney weight, and body surface in normal man.</a> Anat Rec. 232 (2), 514-201 (1992).</li><li>Keller, G., Zimmer, G., Mall, G., Ritz, E., Amann, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nephron+number+in+patients+with+primary+hypertension.">Nephron number in patients with primary hypertension.</a> N Engl J Med. 348 (2), 101-108 (2003).</li><li>Cullen-McEwen, L. A., Kett, M. M., Dowling, J., Anderson, W. P., Bertram, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nephron+number,+renal+function,+and+arterial+pressure+in+aged+GDNF+heterozygous+mice.">Nephron number, renal function, and arterial pressure in aged GDNF heterozygous mice.</a> Hypertension. 41 (2), 335-340 (2003).</li><li>Gerlach, G. F., Wingert, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kidney+organogenesis+in+the+zebrafish:+insights+into+vertebrate+nephrogenesis+and+regeneration.">Kidney organogenesis in the zebrafish: insights into vertebrate nephrogenesis and regeneration.</a> Wiley Interdiscip Rev Dev Biol. 2 (5), 559-585 (2013).</li><li>Igarashi, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overview:+nonmammalian+organisms+for+studies+of+kidney+development+and+disease.">Overview: nonmammalian organisms for studies of kidney development and disease.</a> J Am Soc Nephrol. 16 (2), 296-298 (2005).</li><li>Zhou, W., Boucher, R. C., Bollig, F., Englert, C., Hildebrandt, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+mesonephric+development+and+regeneration+using+transgenic+zebrafish.">Characterization of mesonephric development and regeneration using transgenic zebrafish.</a> Am J Physiol Renal Physiol. 299 (5), 1040-1047 (2010).</li><li>Liu, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+defect+in+a+novel+Nek-family+kinase+causes+cystic+kidney+disease+in+the+mouse+and+in+zebrafish.">A defect in a novel Nek-family kinase causes cystic kidney disease in the mouse and in zebrafish.</a> Development. 129 (24), 5839-5846 (2002).</li><li>Slanchev, K., Putz, M., Schmitt, A., Kramer-Zucker, A., Walz, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nephrocystin-4+is+required+for+pronephric+duct-dependent+cloaca+formation+in+zebrafish.">Nephrocystin-4 is required for pronephric duct-dependent cloaca formation in zebrafish.</a> Hum Mol Genet. 20 (16), 3119-3128 (2011).</li><li>Huang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+Wnt5a+in+prostate+gland+development.">The role of Wnt5a in prostate gland development.</a> Dev Biol. 328 (2), 188-199 (2009).</li><li>Andre, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Wnt+coreceptor+Ryk+regulates+Wnt/planar+cell+polarity+by+modulating+the+degradation+of+the+core+planar+cell+polarity+component+Vangl2.">The Wnt coreceptor Ryk regulates Wnt/planar cell polarity by modulating the degradation of the core planar cell polarity component Vangl2.</a> J Biol Chem. 287 (53), 44518-44525 (2012).</li><li>Kimmel, C. B., Ballard, W. W., Kimmel, S. R., Ullmann, B., Schilling, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stages+of+embryonic+development+of+the+zebrafish.">Stages of embryonic development of the zebrafish.</a> Dev Dyn. 203 (3), 253-310 (1995).</li><li>Torres, V. E., Harris, P. C., Pirson, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Autosomal+dominant+polycystic+kidney+disease.">Autosomal dominant polycystic kidney disease.</a> Lancet. 369 (9569), 1287-1301 (2007).</li></ol>

Polycystic kidney disease (PKD) is one of the leading causes of end-stage renal disease in humans and is characterized by progressive cyst formation, renal enlargement, and abnormal tubule development 14. Autosomal dominant PKD (ADPKD) is a genetic disease in which mutation of either PKD1, encoding polycystin-1 (PC1), or PKD2, encoding polycystin-2 (PC2), results in polycystic kidneys. Many other genes, especially those encoding proteins found in the primary cilium, are thought to be involved in the developmen...

Zebrafish (Danio rerio) embryos have been widely used as a model for studying kidney development and polycystic kidney disease. There are many advantages to using zebrafish as an animal model: the feasibility of studying genetic interactions, the ability to use antisense morpholinos (MO) for protein knockdown, the opportunity to quickly assay large numbers of embryos, and the ease of viewing organ phenotypes in living larvae 1. The pronephros is the first kidney to develop in vertebrates and is functional in larval zebrafish 2. The structure of the zebrafish pronephros is relatively simple compared to the mammalian metanephros, the third and final kidney to develop in mammals. The nephron is the working unit of the kidney, with each human kidney containing between 500,000-1,000,000 nephrons3,4 and each mouse kidney having approximately 13,000 nephrons5, making it difficult to observe single nephron structure in human or mouse kidneys. The zebrafish has only two nephrons, and each zebrafish nephron contains all the major components found in the glomerulus and tubules of mice and humans6and similar specialized renal cell types. Compared to other vertebrate models such as Xenopus, the zebrafish nephron more closely resembles the mammalian nephron because it has a closed system7.
In recent years, the zebrafish genome has been sequenced, allowing the wide introduction of genetic tools, extensive mutant resources, and collections of transgenic reporter lines in zebrafish models. The zebrafish pronephros forms between 12-72 hr post fertilization (hpf) and can be visualized easily in the transparent embryos. The Wilm&#8217;s tumor protein WT1 is an essential factor for kidney development. Transgenic zebrafish lines expressing green fluorescent protein (GFP) under the control of the wt1b promoter Tg(wt1b:GFP) show GFP expression specifically located in pronephric regions in zebrafish embryos, starting from 17 hpf 8. Nephronophthisis (NPHP), an autosomal recessive cystic kidney disease, is caused by mutations of NPHP genes 9. NPHP4 knockdown by morpholino caused cyst formation in the Tg(wt1b:GFP) fish. 10 Therefore, this transgenic fish is a suitable model for observing kidney structures and cyst formation during kidney development. Importantly, the influence of modulators of kidney development can be studied using this strain in a time and labor efficient manner.
Our paper describes the use of Tg(wt1b:GFP) fish as a model to visualize kidney cyst formation after gene modulation. We used start- and splice-site anti-sense MOs to knock down the wnt5a gene in zebrafish. Wnt5a is a non-canonical secreted glycoprotein of the Wnt family that plays an important role in the development of various organs and postnatal cellular function11. Wnt5a works through non-canonical Wnt pathways, including the planar cell polarity (PCP) pathway, which has been found to play a role in oriented cell division during renal tubular elongation. Wnt5a regulates the Wnt/PCP pathway by forming a complex with the receptor like tyrosine kinase (Ryk), which further transduces Wnt5a signaling by forming a complex with the VANGL planar cell polarity protein 2 (Vangl2), thereby promoting Vangl2 stability 12. Defects in the PCP pathway can result in random cell division and cause renal cyst formation. We used the Tg(wt1b:GFP) zebrafish line to observe kidney cyst formation following wnt5a knockdown. The Tg(wt1b:GFP) zebrafish model allows live imaging and timely observation of kidney structure. After wnt5a knockdown, kidney cyst formation was found beginning at 24 hpf; at 72 hpf, cysts could be found in the glomeruli and the proximal tubules. This method could also be used to screen other genes that might cause kidney cyst formation.

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			<td height="21" style="height:21px;width:221px;">0.5% Phenol-Red</td>
			<td style="width:229px;">Sigma</td>
			<td style="width:195px;">P0290</td>
			<td style="width:491px;">Color indicator for injection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Morpholino</td>
			<td style="width:229px;">Genn Tools, LLC</td>
			<td style="width:195px;">(customized)</td>
			<td>Customized designed to the gene of interest</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:221px;">Pre-pulled needle</td>
			<td style="width:229px;">Tritech Research</td>
			<td style="width:195px;">MINJ-PP</td>
			<td style="width:491px;">If large amount of needle is required, you can also purchase a needle puller and prepare the needle in the lab</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">T7 mMessage Kit</td>
			<td style="width:229px;">Ambion</td>
			<td style="width:195px;">1344</td>
			<td>For in vitro transcription to make capped mRNA for rescue experiment</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">N-Phenylthiourea</td>
			<td style="width:229px;">Sigma</td>
			<td style="width:195px;">P7629</td>
			<td>For prevention of melanization</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Tricaine</td>
			<td style="width:229px;">Sigma</td>
			<td style="width:195px;">A5040</td>
			<td>Also called ethyl 3-aminobenzoate, for zebrafish anesthesia</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Methyl Cellulose</td>
			<td style="width:229px;">Sigma</td>
			<td style="width:195px;">M-0387</td>
			<td>For position of zebrafish&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">QIAquick PCR Purification Kit&#160;</td>
			<td style="width:229px;">Qiagen</td>
			<td style="width:195px;">28104</td>
			<td>For purification of PCR product for cap RNA synthesis.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">dNTP mix</td>
			<td style="width:229px;">Promega</td>
			<td style="width:195px;">U1511</td>
			<td>For PCR</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Tag DNA Polymerase</td>
			<td style="width:229px;">Invitrogen</td>
			<td style="width:195px;">10342-053</td>
			<td>For PCR</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;"></td>
			<td style="width:229px;"></td>
			<td style="width:195px;"></td>
			<td></td>
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			<td style="width:195px;"></td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Equipment</td>
			<td style="width:229px;"></td>
			<td style="width:195px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">NanoDrop sepctrophotometer</td>
			<td style="width:229px;">Thermo Scientific</td>
			<td style="width:195px;">ND-1000</td>
			<td>For measure morpholino and RNA concentration</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Air Compressor</td>
			<td style="width:229px;">Werther International, Inc.</td>
			<td style="width:195px;">Panther Compact 106</td>
			<td>Air source for injection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Pico micro-injection pump</td>
			<td style="width:229px;">World Precision Instruments Inc</td>
			<td style="width:195px;">PV830 Pnematic PicoPump</td>
			<td>Other types of microinjection system can be used.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Micro-manuplator</td>
			<td style="width:229px;">World Precision Instruments Inc</td>
			<td style="width:195px;">MMJR</td>
			<td>Right-handed (MMJL for left handed)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Needle holder</td>
			<td style="width:229px;">World Precision Instruments Inc</td>
			<td style="width:195px;">5430-ALL</td>
			<td>To hold needle for micromanipulation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Dumont Tweezers</td>
			<td style="width:229px;">Fine Surgical Tools</td>
			<td style="width:195px;">11253-20</td>
			<td>For breaking off the needle tip</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Dissecting microscope</td>
			<td>Leica M205C&#160;</td>
			<td style="width:195px;"></td>
			<td>For observing and imaging zebrafish embryos</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Fluorscence microscope</td>
			<td>Zeiss Axio Obserer D1m &#160;</td>
			<td style="width:195px;"></td>
			<td>For imaging zebrafish pronephros</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:221px;">Capillary tube (I.D 0.15 mm)</td>
			<td>VitroCom</td>
			<td style="width:195px;">CV1525Q-100</td>
			<td>For measure the volume of each injected drop</td>
		</tr>
	</tbody>
</table>

a possible zebrafish model of polycystic kidney disease: knockdown of wnt5a causes cysts in zebrafish kidneys

Polycystic kidney disease (PKD) is one of the most common causes of end-stage kidney disease, a devastating disease for which there is no cure. The molecular mechanisms leading to cyst formation in PKD remain somewhat unclear, but many genes are thought to be involved. Wnt5a is a non-canonical glycoprotein that regulates a wide range of developmental processes. Wnt5a works through the planar cell polarity (PCP) pathway that regulates oriented cell division during renal tubular cell elongation. Defects of the PCP pathway have been found to cause kidney cyst formation. Our paper describes a method for developing a zebrafish cystic kidney disease model by knockdown of the wnt5a gene with wnt5a antisense morpholino (MO) oligonucleotides. Tg(wt1b:GFP) transgenic zebrafish were used to visualize kidney structure and kidney cysts following wnt5a knockdown. Two distinct antisense MOs (AUG - and splice-site) were used and both resulted in curly tail down phenotype and cyst formation after wnt5a knockdown. Injection of mouse Wnt5a mRNA, resistant to the MOs due to a difference in primary base pair structure, rescued the abnormal phenotype, demonstrating that the phenotype was not due to &#8220;off-target&#8221; effects of the morpholino. This work supports the validity of using a zebrafish model to study wnt5a function in the kidney.

Wnt5a knock down was achieved by introducing translation blocking MO (AUG-MO) or exon/intron border splice MO (splice-MO) to zebrafish embryos at the one cell stage. The AUG-MO targets the start codon and, therefore, inhibits both maternal and zygotic wnt5a message. The splice-MO targets the third splice donor site and inhibits only the zygotic transcript of wnt5a (Figure&#160;1A). The AUG- and splice- morphants phenocopied each other with multiple defects, including curly tail down bod...

Watch this Scientific Journal Video about A Possible Zebrafish Model of Polycystic Kidney Disease: Knockdown of wnt5a Causes Cysts in Zebrafish Kidneys at JoVE.com

A Possible Zebrafish Model of Polycystic Kidney Disease: Knockdown of wnt5a Causes Cysts in Zebrafish Kidneys

We describe a method of generating a possible zebrafish model of polycystic kidney disease. We used Tg(wt1b:GFP) fish to visualize kidney structure. Knockdown of wnt5a was by morpholino injection. Pronephric cyst formation after wnt5a knockdown was observed in this GFP transgenic zebrafish.

A Possible Zebrafish Model of Polycystic Kidney Disease: Knockdown of wnt5a Causes Cysts in Zebrafish Kidneys

Polycystic kidney disease (PKD) is one of the most common causes of end-stage kidney disease, a devastating disease for which there is no cure. The ...

a-possible-zebrafish-model-polycystic-kidney-disease-knockdown-wnt5a

Research

JoVE Journal

Medicine

Induction of Myocardial Infarction in Adult Zebrafish Using Cryoinjury

The mammalian heart is incapable of significant regeneration following an acute injury such as myocardial infarction1. By contrast, urodele amphibians and teleost fish retain a remarkable capacity for cardiac regeneration with little or no scarring throughout life2,3. It is not known why only some non-mammalian vertebrates can recreate a complete organ from remnant tissues4,5. To understand the molecular and cellular differences between regenerative responses in different species, we need to use similar approaches for inducing acute injuries.
In mammals, the most frequently used model to study cardiac repair has been acute ischemia after a ligation of the coronary artery or tissue destruction after cryoinjury6,7. The cardiac regeneration in newts and zebrafish has been predominantly studied after a partial resection of the ventricular apex2,3. Recently, several groups have established the cryoinjury technique in adult zebrafish8-10. This method has a great potential because it allows a comparative discussion of the results obtained from the mammalian and non-mammalian species.
Here, we present a method to induce a reproducible disc-shaped infarct of the zebrafish ventricle by cryoinjury. This injury model is based on rapid freezing-thawing tissue, which results in massive cell death of about 20% of cardiomyocytes of the ventricular wall. First, a small incision was made through the chest with iridectomy scissors to access the heart. The ventricular wall was directly frozen by applying for 23-25 seconds a stainless steel cryoprobe precooled in liquid nitrogen. To stop the freezing of the heart, fish water at room temperature was dropped on the tip of the cryoprobe. The procedure is well tolerated by animals, with a survival rate of 95%.
To characterize the regenerative process, the hearts were collected and fixed at different days after cryoinjury. Subsequently, the specimen were embedded for cryosectioning. The slides with sections were processed for histological analysis, in situ hybridization and immunofluorescence. This undertaking enhances our understanding of the factors that are required for the regenerative plasticity in the zebrafish, and provide new insights into the machinery of cardiac regeneration. A conceptual and molecular understanding of heart regeneration in zebrafish will impact both developmental biology and regenerative medicine.

Zebrafish represents a valuable model to study the mechanisms of heart regeneration in vertebrates. Here, we present a protocol for induction of a heart infarct in adult zebrafish using cryoinjury. This method results in massive cell death within 20% of the ventricular wall, similar to that observed in mammalian infarcts.

The mammalian heart is incapable of significant regeneration following an acute injury such as myocardial infarction1. By contrast, urodele amphibians and ...

Assessing Teratogenic Changes in a Zebrafish Model of Fetal Alcohol Exposure

Fetal alcohol syndrome (FAS) is a severe manifestation of embryonic exposure to ethanol. It presents with characteristic defects to the face and organs, including mental retardation due to disordered and damaged brain development. Fetal alcohol spectrum disorder (FASD) is a term used to cover a continuum of birth defects that occur due to maternal alcohol consumption, and occurs in approximately 4% of children born in the United States. With 50% of child-bearing age women reporting consumption of alcohol, and half of all pregnancies being unplanned, unintentional exposure is a continuing issue2. In order to best understand the damage produced by ethanol, plus produce a model with which to test potential interventions, we developed a model of developmental ethanol exposure using the zebrafish embryo. Zebrafish are ideal for this kind of teratogen study3-8. Each pair lays hundreds of eggs, which can then be collected without harming the adult fish. The zebrafish embryo is transparent and can be readily imaged with any number of stains. Analysis of these embryos after exposure to ethanol at different doses and times of duration and application shows that the gross developmental defects produced by ethanol are consistent with the human birth defect. Described here are the basic techniques used to study and manipulate the zebrafish FAS model.

In order to understand the molecular mechanisms of the ethanol-induced developmental damage, we have developed a zebrafish model of ethanol exposure and are exploring the physical, cellular, and genetic alterations that occur after ethanol exposure1. We then seek to find potential interventions and rapidly test them in this animal model.

Fetal alcohol syndrome (FAS) is a severe manifestation of embryonic exposure to ethanol. It presents with characteristic defects to the face and organs, ...

Spectral Karyotyping to Study Chromosome Abnormalities in Humans and Mice with Polycystic Kidney Disease

Conventional method to identify and classify individual chromosomes depends on the unique banding pattern of each chromosome in a specific species being analyzed 1, 2. This classical banding technique, however, is not reliable in identifying complex chromosomal aberrations such as those associated with cancer. To overcome the limitations of the banding technique, Spectral Karyotyping (SKY) is introduced to provide much reliable information on chromosome abnormalities.
SKY is a multicolor fluorescence in-situ hybridization (FISH) technique to detect metaphase chromosomes with spectral microscope 3, 4. SKY has been proven to be a valuable tool for the cytogenetic analysis of a broad range of chromosome abnormalities associated with a large number of genetic diseases and malignancies 5, 6. SKY involves the use of multicolor fluorescently-labelled DNA probes prepared from the degenerate oligonucleotide primers by PCR. Thus, every chromosome has a unique spectral color after in-situ hybridization with probes, which are differentially labelled with a mixture of fluorescent dyes (Rhodamine, Texas Red, Cy5, FITC and Cy5.5). The probes used for SKY consist of up to 55 chromosome specific probes 7-10.
The procedure for SKY involves several steps (Figure 1). SKY requires the availability of cells with high mitotic index from normal or diseased tissue or blood. The chromosomes of a single cell from either a freshly isolated primary cell or a cell line are spread on a glass slide. This chromosome spread is labeled with a different combination of fluorescent dyes specific for each chromosome. For probe detection and image acquisition,the spectral imaging system consists of sagnac interferometer and a CCD camera. This allows measurement of the visible light spectrum emitted from the sample and to acquire a spectral image from individual chromosomes. HiSKY, the software used to analyze the results of the captured images, provides an easy identification of chromosome anomalies. The end result is a metaphase and a karyotype classification image, in which each pair of chromosomes has a distinct color (Figure 2). This allows easy identification of chromosome identities and translocations. For more details, please visit Applied Spectral Imaging website (<a href="http://www.spectral-imaging.com/" target="_blank">http://www.spectral-imaging.com/</a>).
SKY was recently used for an identification of chromosome segregation defects and chromosome abnormalities in humans and mice with Autosomal Dominant Polycystic Kidney Disease (ADPKD), a genetic disease characterized by dysfunction in primary cilia 11-13. Using this technique, we demonstrated the presence of abnormal chromosome segregation and chromosomal defects in ADPKD patients and mouse models 14. Further analyses using SKY not only allowed us to identify chromosomal number and identity, but also to accurately detect very complex chromosomal aberrations such as chromosome deletions and translocations (Figure 2).

Spectral Karyotyping (SKY) is an advanced cytogenetics technique to identify genomic and chromosomal aberrations. This technique takes advantage of chromosome painting probes, which allow classification of all chromosomes. SKY can also identify complex chromosome aberrations and segregation defects in mice and humans with various diseases, including polycystic kidney disease.

Conventional method to identify and classify individual chromosomes depends on the unique banding pattern of each chromosome in a specific species being ...

Screening for Melanoma Modifiers using a Zebrafish Autochthonous Tumor Model

Genomic studies of human cancers have yielded a wealth of information about genes that are altered in tumors1,2,3. A challenge arising from these studies is that many genes are altered, and it can be difficult to distinguish genetic alterations that drove tumorigenesis from that those arose incidentally during transformation. To draw this distinction it is beneficial to have an assay that can quantitatively measure the effect of an altered gene on tumor initiation and other processes that enable tumors to persist and disseminate. Here we present a rapid means to screen large numbers of candidate melanoma modifiers in zebrafish using an autochthonous tumor model4 that encompasses steps required for melanoma initiation and maintenance. A key reagent in this assay is the miniCoopR vector, which couples a wild-type copy of the mitfa melanocyte specification factor to a Gateway recombination cassette into which candidate melanoma genes can be recombined5. The miniCoopR vector has a mitfa rescuing minigene which contains the promoter, open reading frame and 3'-untranslated region of the wild-type mitfa gene. It allows us to make constructs using full-length open reading frames of candidate melanoma modifiers. These individual clones can then be injected into single cell Tg(mitfa:BRAFV600E);p53(lf);mitfa(lf)zebrafish embryos. The miniCoopR vector gets integrated by Tol2-mediated transgenesis6 and rescues melanocytes. Because they are physically coupled to the mitfa rescuing minigene, candidate genes are expressed in rescued melanocytes, some of which will transform and develop into tumors. The effect of a candidate gene on melanoma initiation and melanoma cell properties can be measured using melanoma-free survival curves, invasion assays, antibody staining and transplantation assays.

A rapid way to screen for melanoma modifiers using a zebrafish autochthonous tumor model is presented. It takes advantage of the miniCoopR vector which allows for expression of candidate melanoma genes in melanocytes. A method to obtain melanoma-free survival curves, an invasion assay, a protocol for antibody staining of scale melanocytes and a melanoma transplantation assay are described.

Genomic studies of  human cancers have yielded a wealth of information about genes that are altered  in tumors1,2,3. A challenge arising from these ...

A Zebrafish Model of Diabetes Mellitus and Metabolic Memory

Diabetes mellitus currently affects 346 million individuals and this is projected to increase to 400 million by 2030. Evidence from both the laboratory and large scale clinical trials has revealed that diabetic complications progress unimpeded via the phenomenon of metabolic memory even when glycemic control is pharmaceutically achieved. Gene expression can be stably altered through epigenetic changes which not only allow cells and organisms to quickly respond to changing environmental stimuli but also confer the ability of the cell to "memorize" these encounters once the stimulus is removed. As such, the roles that these mechanisms play in the metabolic memory phenomenon are currently being examined.
We have recently reported the development of a zebrafish model of type I diabetes mellitus and characterized this model to show that diabetic zebrafish not only display the known secondary complications including the changes associated with diabetic retinopathy, diabetic nephropathy and impaired wound healing but also exhibit impaired caudal fin regeneration. This model is unique in that the zebrafish is capable to regenerate its damaged pancreas and restore a euglycemic state similar to what would be expected in post-transplant human patients. Moreover, multiple rounds of caudal fin amputation allow for the separation and study of pure epigenetic effects in an in vivo system without potential complicating factors from the previous diabetic state. Although euglycemia is achieved following pancreatic regeneration, the diabetic secondary complication of fin regeneration and skin wound healing persists indefinitely. In the case of impaired fin regeneration, this pathology is retained even after multiple rounds of fin regeneration in the daughter fin tissues. These observations point to an underlying epigenetic process existing in the metabolic memory state. Here we present the methods needed to successfully generate the diabetic and metabolic memory groups of fish and discuss the advantages of this model.

Metabolic memory is the phenomenon by which diabetic complications persist and progress unimpeded even after euglycemia is achieved pharmaceutically. Here we describe a diabetes mellitus zebrafish model which is unique in that it allows for the examination of the mitotically transmissible epigenetic components of metabolic memory in vivo.

Diabetes mellitus currently affects 346 million individuals and this is projected to increase to 400 million by 2030. Evidence from both the laboratory ...

Assessment of Vascular Function in Patients With Chronic Kidney Disease

Patients with chronic kidney disease (CKD) have significantly increased risk of cardiovascular disease (CVD) compared to the general population, and this is only partially explained by traditional CVD risk factors. Vascular dysfunction is an important non-traditional risk factor, characterized by vascular endothelial dysfunction (most commonly assessed as impaired endothelium-dependent dilation [EDD]) and stiffening of the large elastic arteries. While various techniques exist to assess EDD and large elastic artery stiffness, the most commonly used are brachial artery flow-mediated dilation (FMDBA) and aortic pulse-wave velocity (aPWV), respectively. Both of these noninvasive measures of vascular dysfunction are independent predictors of future cardiovascular events in patients with and without kidney disease. Patients with CKD demonstrate both impaired FMDBA, and increased aPWV. While the exact mechanisms by which vascular dysfunction develops in CKD are incompletely understood, increased oxidative stress and a subsequent reduction in nitric oxide (NO) bioavailability are important contributors. Cellular changes in oxidative stress can be assessed by collecting vascular endothelial cells from the antecubital vein and measuring protein expression of markers of oxidative stress using immunofluorescence. We provide here a discussion of these methods to measure FMDBA, aPWV, and vascular endothelial cell protein expression.

The degree of vascular dysfunction and contributing physiological mechanisms can be assessed in patients with chronic kidney disease by measuring brachial artery flow-mediated dilation, aortic pulse-wave velocity, and vascular endothelial cell protein expression.

Patients with chronic kidney disease (CKD) have significantly increased risk of cardiovascular disease (CVD) compared to the general population, and this ...

Use of Ultra-high Field MRI in Small Rodent Models of Polycystic Kidney Disease for In Vivo Phenotyping and Drug Monitoring

Several in vivo pre-clinical studies in Polycystic Kidney Disease (PKD) utilize orthologous rodent models to identify and study the genetic and molecular mechanisms responsible for the disease, and are very convenient for rapid drug screening and testing of promising therapies. A limiting factor in these studies is often the lack of efficient non-invasive methods for sequentially analyzing the anatomical and functional changes in the kidney. Magnetic resonance imaging (MRI) is the current gold standard imaging technique to follow autosomal dominant polycystic kidney disease (ADPKD) patients, providing excellent soft tissue contrast and anatomic detail and allowing Total Kidney Volume (TKV) measurements.A major advantage of MRI in rodent models of PKD is the possibility for in vivo imaging allowing for longitudinal studies that use the same animal and therefore reducing the total number of animals required. In this manuscript, we will focus on using Ultra-high field (UHF) MRI to non-invasively acquire in vivo images of rodent models for PKD. The main goal of this work is to introduce the use of MRI as a tool for in vivo phenotypical characterization and drug monitoring in rodent models for PKD.

Use of Ultra-high Field MRI in Small Rodent Models of Polycystic Kidney Disease for In Vivo Phenotyping and Drug Monitoring

The use of ultra-high field MRI as a non-invasive way to obtain phenotypic information of rodent models for polycystic kidney disease and to monitor interventions is described. Compared with the traditional histological approach, MRI images can be acquired in vivo, allowing for longitudinal follow-up.

Several in vivo pre-clinical studies in Polycystic Kidney Disease (PKD) utilize orthologous rodent models to identify and study the genetic and molecular ...

A Doxorubicin-induced Cardiomyopathy Model in Adult Zebrafish

The genetically accessible adult zebrafish (Danio rerio) has been increasingly used as a vertebrate model for understanding human diseases such as cardiomyopathy. Because of its convenience and amenability to high throughput genetic manipulations, the generation of acquired cardiomyopathy models, such as the doxorubicin-induced cardiomyopathy (DIC) model in adult zebrafish, is opening the doors to new research avenues, including discovering cardiomyopathy modifiers via forward genetic screening. Different from the embryonic zebrafish DIC model, both initial acute and later chronic phases of cardiomyopathy can be determined in the adult zebrafish DIC model, enabling the study of stage-dependent signaling mechanisms and therapeutic strategies. However, variable results can be obtained with the current model, even in the hands of experienced investigators. To facilitate future implementation of the DIC model, we present a detailed protocol on how to generate this DIC model in adult zebrafish and describe two alternative ways of intraperitoneal (IP) injection. We further discuss options on how to reduce variations to obtain reliable results and provide suggestions on how to appropriately interpret the results.

A method to generate a doxorubicin-induced cardiomyopathy model in adult zebrafish (Danio rerio) is described here. Two alternative ways of intraperitoneal injection are presented and conditions to reduce variations among different experimental groups are discussed.

The genetically accessible adult zebrafish (Danio rerio) has been increasingly used as a vertebrate model for understanding human diseases such as ...

Assessment of Kidney Function in Mouse Models of Glomerular Disease

The use of murine models to mimic human kidney disease is becoming increasingly common. Our research is focused on the assessment of glomerular function in diabetic nephropathy and podocyte-specific VEGF-A knock-out mice; therefore, this protocol describes the full kidney work-up used in our lab to assess these mouse models of glomerular disease, enabling a vast amount of information regarding kidney and glomerular function to be obtained from a single mouse. In comparison to alternative methods presented in the literature to assess glomerular function, the use of the method outlined in this paper enables the glomerular phenotype to be fully evaluated from multiple aspects. By using this method, the researcher can determine the kidney phenotype of the model and assess the mechanism as to why the phenotype develops. This vital information on the mechanism of disease is required when examining potential therapeutic avenues in these models. The methods allow for detailed functional assessment of the glomerular filtration barrier through measurement of the urinary albumin creatinine ratio and individual glomerular water permeability, as well as both structural and ultra-structural examination using the Periodic Acid Schiff stain and electron microscopy. Furthermore, analysis of the genes dysregulated at the mRNA and protein level enables mechanistic analysis of glomerular function. This protocol outlines the generic but adaptable methods that can be applied to all mouse models of glomerular disease.

This protocol describes a full kidney work-up that should be carried out in mouse models of glomerular disease. The methods allow for detailed functional, structural, and mechanistic analysis of glomerular function, which can be applied to all mouse models of glomerular disease.

The use of murine models to mimic human kidney disease is becoming increasingly common. Our research is focused on the assessment of glomerular function ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...