Name: organ culture and whole mount immunofluorescence staining of mouse wolffian ducts
Uploaded: 2017-01-13T15:00:00
Description: Watch this Scientific Journal Video about Organ Culture and Whole Mount Immunofluorescence Staining of Mouse Wolffian Ducts at JoVE.com

We would like to thank members of the gynaecology oncology group for critical reading of this manuscript. This work is in part supported by funding from the National Health and Medical Research Council, the Australian Research Council, and the Cancer Institute NSW (P.S.T). M.K. is a recipient of the University of Newcastle Postgraduate Research Fellowship.

Animal care and experimental procedures were conducted in accordance with the guidelines of the Animal Care and Ethics Committee of the University of Newcastle and confirmed to the New South Wales Animal Research Act, New South Wales Animal Research Regulation, and the Australian code for the care and use of animals for scientific purposes. All the procedures undertaken on mice were approved by the Animal Care and Ethics Committee of the University of Newcastle.
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	<li>Joseph, A., Yao, H., Hinton, B. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+morphogenesis+of+the+Wolffian/epididymal+duct,+more+twists+and+turns.">Development and morphogenesis of the Wolffian/epididymal duct, more twists and turns.</a> Dev Biol. 325, 6-14 (2009).</li><li>Murashima, A., Xu, B., Hinton, B. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Understanding+normal+and+abnormal+development+of+the+Wolffian/epididymal+duct+by+using+transgenic+mice.">Understanding normal and abnormal development of the Wolffian/epididymal duct by using transgenic mice.</a> Asian J Androl. 17, 1-7 (2015).</li><li>Carroll, T. J., Park, J. S., Hayashi, S., Majumdar, A., McMahon, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Wnt9b+plays+a+central+role+in+the+regulation+of+mesenchymal+to+epithelial+transitions+underlying+organogenesis+of+the+mammalian+urogenital+system.">Wnt9b plays a central role in the regulation of mesenchymal to epithelial transitions underlying organogenesis of the mammalian urogenital system.</a> Dev Cell. 9, 283-292 (2005).</li><li>Kumar, M., Syed, S. M., Taketo, M. M., Tanwar, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epithelial+Wnt/&#946;catenin+signalling+is+essential+for+epididymal+coiling.">Epithelial Wnt/&#946;catenin signalling is essential for epididymal coiling.</a> Dev Biol. 412, 234-249 (2016).</li><li>Murashima, A., 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=Essential+roles+of+androgen+signaling+in+Wolffian+duct+stabilization+and+epididymal+cell+differentiation.">Essential roles of androgen signaling in Wolffian duct stabilization and epididymal cell differentiation.</a> Endocrinology. 152, 1640-1651 (2011).</li><li>Lin, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applications+and+limitations+of+genetically+modified+mouse+models+in+drug+discovery+and+development.">Applications and limitations of genetically modified mouse models in drug discovery and development.</a> Curr Drug Metab. 9, 419-438 (2008).</li><li>Rak-Raszewska, A., Hauser, P. V., Vainio, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organ+In+Vitro+Culture:+What+Have+We+Learned+about+Early+Kidney+Development?.">Organ In Vitro Culture: What Have We Learned about Early Kidney Development?.</a> Stem Cells Int. 959807, 1-16 (2015).</li><li>Hirashima, T., Adachi, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Procedures+for+the+Quantification+of+Whole-Tissue+Immunofluorescence+Images+Obtained+at+Single-Cell+Resolution+during+Murine+Tubular+Organ+Development.">Procedures for the Quantification of Whole-Tissue Immunofluorescence Images Obtained at Single-Cell Resolution during Murine Tubular Organ Development.</a> PLoS One. 10, 0135343 (2015).</li><li>Chan, W. Y., Blomberg, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Germline+Development:+Methods+and+Protocols.">Germline Development: Methods and Protocols.</a> Methods Mol Biol. 825, (2012).</li><li>Karner, C. M., 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=Tankyrase+Is+Necessary+for+Canonical+Wnt+Signaling+During+Kidney+Development.">Tankyrase Is Necessary for Canonical Wnt Signaling During Kidney Development.</a> Dev Dyn. 239, 2014-2023 (2010).</li><li>Traykova-Brauch, M., 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=An+efficient+and+versatile+system+for+acute+and+chronic+modulation+of+renal+tubular+function+in+transgenic+mice.">An efficient and versatile system for acute and chronic modulation of renal tubular function in transgenic mice.</a> Nat Med. 14, 979-984 (2008).</li></ol>

The organ culture system has many advantages over the traditional cell culture system. This system retains the original structural relationships and interactions between different cell types. It mimics in vivo systems and gives more accurate information than cell culture studies where the niche factor is absent. The use of organ culture systems even have advantages over using the whole animal. These include the higher cost of using the whole animal, easy care and maintenance of organ culture system, etc.</em...

The male reproductive system primarily consists of testis, the site for germ cell development and differentiation, and a complex ductal system that is required for the maturation, transport, and storage of sperm. Epididymis is a tubular organ that connects testis with vas deferens and mainly involved in post-testicular development and maturation of germ cells 1. The highly coiled adult mouse epididymis develops from a simple and straight precursor tube, Wolffian duct (WD) 1. The complex and coiled structure of epididymis is essential for sperm to acquire the capacity to fertilize female germ cells 2. How such an essential organ for male fertility develops and gets into shape is not well understood. Various signaling pathways have been shown to be involved in the development of WD such as the Wnt signaling pathway 3,4 and the androgen signaling pathway 5. Our recent work has established the requirement of balanced Wnt signaling&#160;for WD coiling during prenatal development 4. However, further studies are required to understand the mechanisms involved in postnatal epididymal coiling, cellular differentiation, and cell-to-cell communication within the epididymal epithelium and with interstitial cells.
Genetically modified mouse models have been proven to be a powerful tool for identification/validation of molecular mechanisms underlying development and disease of various organ systems 6. Despite its extensive use, there are significant limitations of genetically modified mouse models, including the unpredicted phenotype of targeted mouse mutants with regards to presumed gene function, and no phenotype in null mutants in some models, influence of genetic and environmental factors, labor intensive and time-consuming process of developing mouse models. Therefore, the interpretation of the significance of the findings only from genetically modified mouse models is not always straightforward 6. These limitations can be overcome by using in vitro organ culture system which gives us the flexibility to manipulate multiple signaling pathways in real time in controlled culture conditions. Organ culture system is instrumental in understanding the physiology and pathology of whole organs 7. Moreover, imaging of whole organs stained with fluorophore labeled antibodies enables us to visualize the markers of interest in a three-dimensional context, as it exists in vivo, thereby providing a better understanding of the organ&#39;s shape, structure, and function 8.
Here, we have described the methods for isolation of mouse embryonic gonadal ridges, in vitro culture&#160;and whole mount immunofluorescence imaging of WDs, that can be applied to answer a variety of questions concerning the morphogenesis of tubular organs such as WDs. In this protocol, we isolated mouse embryonic urogenital ridges from 15.5 days post coitum (dpc) pregnant dams and cultured them for 3 d&#160;followed by immunostaining for an epithelial cell marker (cytokeratin 8, CK8), a cell proliferation marker (phospho-Histone 3, PH3) and active &#946;catenin.

<table border="0" cellpadding="0" cellspacing="0" width="769">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">24 well plates</td>
			<td style="width:195px;">Corning, USA</td>
			<td style="width:136px;">3524</td>
			<td style="width:191px;">can be purchased from other vendors</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Hank&#8217;s Balanced Salt Solution (HBSS)</td>
			<td style="width:195px;">GE Healthcare Life Sciences, USA</td>
			<td style="width:136px;">SH30031.02</td>
			<td style="width:191px;">can be purchased from other vendors</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Dulbecco&#39;s Modified Eagle Medium: Nutrient Mixture F-12 (DMEM/F12)</td>
			<td style="width:195px;">Sigma, USA</td>
			<td style="width:136px;">D8437</td>
			<td style="width:191px;">Warm in 37 &#176;C water bath before use</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Fetal Bovine Serum (FBS)</td>
			<td style="width:195px;">Interpath,&#160; Australia</td>
			<td style="width:136px;">SH30034.02</td>
			<td style="width:191px;">10% FBS used in culture medium</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">L-Glutamine</td>
			<td style="width:195px;">GE Healthcare Life Sciences, USA</td>
			<td style="width:136px;">SH30034.01</td>
			<td style="width:191px;">1% concentration used</td>
		</tr>
		<tr height="62">
			<td height="62" style="height:62px;width:247px;">Penicillin-Streptomycin</td>
			<td style="width:195px;">Gibco, USA</td>
			<td style="width:136px;">15070-063</td>
			<td style="width:191px;">1% concentration used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Whatman Nuclepore Polycarbonate Track-Etch&#160;</td>
			<td style="width:195px;">Whatman, USA</td>
			<td style="width:136px;">110409</td>
			<td style="width:191px;">Membrane (0.8 mm)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">IWR1</td>
			<td style="width:195px;">Sigma, USA</td>
			<td style="width:136px;">10161-5mg</td>
			<td style="width:191px;">100 &#181;M concentration used</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:247px;">Paraformaldehyde (PFA)</td>
			<td style="width:195px;">Electron Microscopy Sciences, USA</td>
			<td style="width:136px;">15710</td>
			<td style="width:191px;">16% stock, 4% in PBS for use. TOXIC - wear gloves and cannot 
			be disposed of in the sink</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Ethanol</td>
			<td style="width:195px;">Thermo Scientific Fisher, USA</td>
			<td style="width:136px;">214-20L PL</td>
			<td style="width:191px;">Absolute, make 25, 50 and 75% with milliQ water.</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Tween-20</td>
			<td style="width:195px;">Thermo Scientific Fisher, USA</td>
			<td style="width:136px;">2509-500ml</td>
			<td style="width:191px;">Very viscous, careful while dispensing</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Triton X-100</td>
			<td style="width:195px;">Sigma, USA</td>
			<td style="width:136px;">T8787-50ml</td>
			<td style="width:191px;">Very viscous, careful while dispensing</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Di-Sodium Hydrogen Phosphate</td>
			<td style="width:195px;">Thermo Scientific Fisher, USA</td>
			<td style="width:136px;">621-500mg</td>
			<td style="width:191px;">can be purchased from other vendors</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Sodium Di-hydrogen Phosphate</td>
			<td style="width:195px;">Ajax Finechem, USA</td>
			<td style="width:136px;">4745-500g</td>
			<td style="width:191px;">can be purchased from other vendors</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Sodium Chloride</td>
			<td style="width:195px;">Thermo Scientific Fisher, USA</td>
			<td style="width:136px;">465-500g</td>
			<td style="width:191px;">can be purchased from other vendors</td>
		</tr>
		<tr height="83">
			<td height="83" style="height:83px;width:247px;">Cytokeratin8/Troma I</td>
			<td style="width:195px;">Developmental Studies Hybridoma Bank, USA (DHSB)</td>
			<td style="width:136px;">TROMA-I</td>
			<td style="width:191px;">1:250 in blocking buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">active &#946;catenin&#160;</td>
			<td style="width:195px;">Cell Signalling Technology,&#160; USA</td>
			<td style="width:136px;">D13A1</td>
			<td style="width:191px;">1:200 in blocking buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;"></td>
			<td style="width:195px;"></td>
			<td style="width:136px;"></td>
			<td style="width:191px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:247px;">Phospho-Histone3</td>
			<td style="width:195px;">Millipore, MA, USA</td>
			<td style="width:136px;">06-570</td>
			<td style="width:191px;">1:200 in blocking buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Alexa488 Goat anti-rabbit IgG</td>
			<td style="width:195px;">Jackson ImmunoResearchLabs,&#160; USA</td>
			<td style="width:136px;">111-545-047</td>
			<td style="width:191px;">1:250 in blocking buffer</td>
		</tr>
		<tr height="45">
			<td height="45" style="height:45px;width:247px;">Alexa594 Goat anti-Rat IgG</td>
			<td style="width:195px;">Jackson ImmunoResearchLabs,&#160; USA</td>
			<td style="width:136px;">112-585-072</td>
			<td style="width:191px;">1:250 in blocking buffer</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">Glycerol</td>
			<td style="width:195px;">Thermo Fisher Scientific, USA</td>
			<td style="width:136px;">242-500ml</td>
			<td style="width:191px;">can be purchased from other vendors</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">n-Propyl galate</td>
			<td style="width:195px;">Sigma, USA</td>
			<td style="width:136px;">2370</td>
			<td>-</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:247px;">2-(4-amidinophenyl)-1H -indole-6-carboxamidine (DAPI)</td>
			<td style="width:195px;">Sigma, USA</td>
			<td style="width:136px;">D9564-10mg</td>
			<td style="width:191px;">Use to stain nucleic acids (DNA)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Dimethyl sulfoxide (DMSO)</td>
			<td style="width:195px;">Thermo Fisher Scientific, USA</td>
			<td style="width:136px;">2225-500ml</td>
			<td style="width:191px;">Solvent</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:247px;">Cover Slips (24x50 mm)</td>
			<td style="width:195px;">Lomb Scientific</td>
			<td style="width:136px;">CS24501GP</td>
			<td>-</td>
		</tr>
	</tbody>
</table>

organ culture and whole mount immunofluorescence staining of mouse wolffian ducts

Tubal morphogenesis is a fundamental requirement for the development of most mammalian organs, including the male reproductive system. The epididymis, an integral part of the male reproductive tract, is responsible for sperm storage, maturation, and transport. The adult epididymis is a highly coiled tube that develops from a simple and straight embryonic precursor known as Wolffian duct (WD). Proper coiling of the epididymis is essential for male fertility, as sperm in the testis are unable to fertilize an oocyte. However, the mechanism responsible for epididymal development and coiling remains unclear, partially due to the lack of whole organ culture and imaging methods. In this study, we describe an in vitro culture system and whole mount immunofluorescence protocol to better visualize the process of WD coiling and development, which may also be applied to study other tubular organs.

During development, the WD undergoes significant changes wherein a simple and straight tube is transformed into a highly complex and coiled duct. Using methods described above, WDs undergo a similar transformation in culture conditions. Here we have shown the results from WDs cultured for 3 d&#160;(Figure 3). To dissect molecular mechanisms involved in WD morphogenesis, the culture medium can be supplemented with inhibitors and activators targeting different signaling pathways. Figure 3C...

Watch this Scientific Journal Video about Organ Culture and Whole Mount Immunofluorescence Staining of Mouse Wolffian Ducts at JoVE.com

Organ Culture and Whole Mount Immunofluorescence Staining of Mouse Wolffian Ducts

We present a method for isolation and culture of the mouse Wolffian duct (WD). We also demonstrate a detailed procedure for whole mount immunostaining of cultured/freshly isolated WDs with fluorescently tagged antibodies. Together, these techniques enable the study of WD development, coiling, and differentiation.

Tubal morphogenesis is a fundamental requirement for the development of most mammalian organs, including the male reproductive system. The epididymis, an ...

The overall goal of this organ culture and whole mount immunofluorescene method is to better visualize and understand the process of Wolffian induct coiling and development. This method will help to answer key questions in the field of developmental biology about the mechanisms involved in development of organ shape, structure, and function. The main advantages of this technique are that it mimics in vivo systems and provides more accuracte information than cell culture studies which lack niche factors.Before noon on day 15 post-conception, place a pregnant mouse in the supine position on absorbent tissue paper, and spray the ventral side of the abdomen with 70%ethanol. Using forceps, lift the lower abdominal skin on the ventral side of the animal, and use surgical scissors to make a lateral incision extending from the urogenital opening to the rib cage. Grasp the urinary bladder with the forceps just above the cervix, and make an incision into the uterus.Holding the urinary bladder, make an incision into the uterine broad ligament, and utero tubal junction to detach the uterus from paratenigal attachment. Place the uterus in a 50 milliliter tube containing ice cold HBSS, and gently agitate the tissue to remove the excess blood. Transfer the rinsed uterus to a Petri dish containing fresh ice cold HBSS on ice, and cut the uterine wall to remove the embryos, placing them in a new Petri dish with fresh HBSS on ice as they are harvested.Place an embryo on its lateral side onto an ethanol-soaked sterile piece of tissue paper in a new dish. And use a sterile blade to make a diagonal incision across the lower abdomen of the animal. Pin the embryo on a sterile sponge base along the vertebral column, and move the embryo under a dissecting stereo microscope.Carefully cut along the ventral mid-line and remove the liver and intestines. The urogenital system should now be visible. Make an incision in the vas deferens, close it its urethral attachment.Followed by an incision thought the attachment of the lower portion of the Wolffian duct to the gubernaculum to harvest the testes and Wolffian ducts. Placing the tissues in a new Petri dish with fresh HBSS on ice as they are collected. To culture the embryonic gonadal ridges, first add 300 microliters of medium per well to a 24-well cell culture plate.Next, add a small drop of sterile HBSS into a new Petri dish and place a 0.8 micrometer poly carbonate track etch membrane onto the drop with the shining surface facing the HBSS. Always place the membrane on the top of the drop of HBSS to keep the tissue hydrated with the rough side of the membrane facing up. Using clean forceps, place two genital ridges onto the rough side of the membrane without the tissues touching each other.And use a sterile wipe to remove the excess HBSS. While you're transferring the genital ridges onto the membrane, pick up the sample between the two arms of forceps, taking care to remove any excess HBSS from the membrane after the transfer to prevent cystic growth of Wolffian ducts. Then place the membrane into one well of the 24-well plate to culture the tissues of the ear medium interface at 37 degrees Celsius, and 5%carbon dioxide, with a total medium change every day for three days.By the fourth day of culture, the uncoiled Wolffian ducts will have transformed into highly convoluted tubes. To fix the tissues for whole mount immunofluorescene, transfer the membranes with the cultured gonads and Wolffian ducts into new Petri dishes containing ice cold PBS. The membranes will float on the PBS.Use the forceps tip to sink the membranes. And transfer the cultured gonadal tissues into 4%paraformaldehyde. After fixation, rinse the samples with three 10-minute washes in in PBS plus Triton X with gentle rocking at room temperature.Then dehydrate the tissues in a graded ethanol series for 10 minutes for each immersion at four degrees Celsius and 30 rotations per minute. To switch the samples between immersions, allow the tissues to settle during the last two minutes of the dehydration. Then remove as much alcohol as possible without touching the tissues, and add the next higher concentration of ethanol.After the last dehydration, rehydrate the tissues in a reverse-graded ethanol series as just demonstrated. Then wash the tissues in PBS plus Triton X four times for 20 minutes at room temperature. And 30 rotations per minute for each wash.Block the tissues for one hour at room temperature with blotting buffer, followed by an overnight incubation at four degrees Celsius and 30 rotations per minute in the primary antibody of interest. The next day wash the tissues four times in PBS plus nonfat milk powder in tween for 30 minutes at room temperature, and 30 rotations per minute for each wash. After the last wash, label the tissues with the appropriate secondary antibody for one hour at room temperature, with slow rocking and protected from light.Then wash the tissues three times in PBS plus tween only. And analyze the samples by immunofluorescene microscopy. During development, the Wolffian duct undergoes significant changes, wherein a simple and straight tube is transformed into a highly complex and coiled duct.To dissect the molecular mechanisms involved in Wolffian duct morphogenesis, the culture medium can be supplemented with inhibitors and activators that target different signaling pathways. For example, this Wolffian duct remained uncoiled after three days of culture in the presence of a one to signaling specific inhibitor. A pathway apparently involved in coiling.Whole mount immunostaining of Wolffian ducts reveals the expression of cytokeratin-8, and the presence of PH3 positive proliferating cells and three-day culture tissues, as well as the expression of beta catenin in freshly-isolated day 18.5 post-conception whole mounted tissues. Once mastered, this technique can be completed in about five to 10 minutes per embryo if performed properly. By following this procedure, pharmacological agents or hormones can be tested on the culture organs to answer additional questions about the direct effect of these agents on specific gonadal tissues.While attempting this procedure, it is important to remember not to grasp the genital ridges directly with the forceps. After its development, this technique paved the way for researchers in the field of developmental biology to explore the mechanisms involved in congenital abnormalities and anomalies development of the reproductive system. After watching this video, you should have a good understanding of how to culture gentile ridges and perform whole-mount immunofluorescene.Don't forget that working with paraformaldehyde can be extremely hazardous, and that personal protective equipment should always be worn while handling this material.

organ-culture-whole-mount-immunofluorescence-staining-mouse-wolffian

Research

JoVE Journal

Developmental Biology

Method of Studying Palatal Fusion using Static Organ Culture

Cleft lip and palate are among the most common of all birth defects. The secondary palate forms from mesenchymal shelves covered with epithelium that adheres to form the midline epithelial seam (MES). The theories suggest that MES cells follow an epithelial to mesenchymal transition (EMT), apoptosis and migration, making a fused palate 1. Complete disintegration of the MES is the final essential phase of palatal confluence with surrounding mesenchymal cells. We provide a method for palate organ culture. The developed in vitro protocol allows the study of the biological and molecular processes during fusion. The applications of this technique are numerous, including evaluating responses to exogenous chemical agents, effects of regulatory and growth factors and specific proteins. Palatal organ culture has a number of advantages including manipulation at different stages of development that is not possible using in vivo studies.

Studies of palate development are motivated by the incidence of cleft palate, a birth defect that imposes a tremendous health burden and can leave lasting disfigurement. We demonstrate here a technique to culture palatal shelves that can be used to study different signaling pathways involved in palatal development and fusion.

Cleft lip and palate are among the most common of all birth defects. The secondary palate forms from mesenchymal shelves covered with epithelium that ...

Reprogramming Mouse Embryonic Fibroblasts with Transcription Factors to Induce a Hemogenic Program

This protocol details the induction of a hemogenic program in mouse embryonic fibroblasts (MEFs) via overexpression of transcription factors (TFs). We first designed a reporter screen using MEFs from human CD34-tTA/TetO-H2BGFP (34/H2BGFP) double transgenic mice. CD34+ cells from these mice label H2B histones with GFP, and cease labeling upon addition of doxycycline (DOX). MEFS were transduced with candidate TFs and then observed for the emergence of GFP+ cells that would indicate the acquisition of a hematopoietic or endothelial cell fate. Starting with 18 candidate TFs, and through a process of combinatorial elimination, we obtained a minimal set of factors that would induce the highest percentage of GFP+ cells. We found that Gata2, Gfi1b, and cFos were necessary and the addition of Etv6 provided the optimal induction. A series of gene expression analyses done at different time points during the reprogramming process revealed that these cells appeared to go through a precursor cell that underwent an endothelial to hematopoietic transition (EHT). As such, this reprogramming process mimics developmental hematopoiesis "in a dish," allowing study of hematopoiesis in vitro and a platform to identify the mechanisms that underlie this specification. This methodology also provides a framework for translation of this work to the human system in the hopes of generating an alternative source of patient-specific hematopoietic stem cells (HSCs) for a number of applications in the treatment and study of hematologic diseases.

The protocol described here details the induction of a hemogenic program in mouse embryonic fibroblasts via overexpression of a minimal set of transcription factors. This technology may be translated to the human system to provide platforms for future study of hematopoiesis, hematologic disease, and hematopoietic stem cell transplant.

This protocol details the induction of a hemogenic program in mouse embryonic fibroblasts (MEFs) via overexpression of transcription factors (TFs). We ...

Visualizing Multiciliated Cells in the Zebrafish Through a Combined Protocol of Whole Mount Fluorescent In Situ Hybridization and Immunofluorescence

In recent years, the zebrafish embryo has emerged as a popular model to study developmental biology due to traits such as ex utero embryo development and optical transparency. In particular, the zebrafish embryo has become an important organism to study vertebrate kidney organogenesis as well as multiciliated cell (MCC) development. To visualize MCCs in the embryonic zebrafish kidney, we have developed a combined protocol of whole-mount fluorescent in situ hybridization (FISH) and whole mount immunofluorescence (IF) that enables high resolution imaging. This manuscript describes our technique for co-localizing RNA transcripts and protein as a tool to better understand the regulation of developmental programs through the expression of various lineage factors.

Visualizing Multiciliated Cells in the Zebrafish Through a Combined Protocol of Whole Mount Fluorescent In Situ Hybridization and Immunofluorescence

Cilia development is vital to proper organogenesis. This protocol describes an optimized method to label and visualize ciliated cells of the zebrafish.

In recent years, the zebrafish embryo has emerged as a popular model to study developmental biology due to traits such as ex utero embryo development and ...

Whole-mount Clearing and Staining of Arabidopsis Flower Organs and Siliques

Due to its formidable tools for molecular genetic studies, Arabidopsis thaliana is one of the most prominent model species in plant biology and, especially, in plant reproductive biology. However, plant morphological, anatomical, and ultrastructural analyses traditionally involve time-consuming embedding and sectioning procedures for bright field, scanning, and electron microscopy. Recent progress in confocal fluorescence microscopy, state-of-the-art 3-D computer-aided microscopic analyses, and the continuous refinement of molecular techniques to be used on minimally processed whole-mount specimens, has led to an increased demand for developing efficient and minimal sample processing techniques. In this protocol, we describe techniques for properly dissecting Arabidopsis flowers and siliques, basic clearing techniques, and some staining procedures for whole-mount observations of reproductive structures.

Whole-mount Clearing and Staining of Arabidopsis Flower Organs and Siliques

In this protocol, we describe techniques for the proper dissection of Arabidopsis flowers and siliques, some basic clearing techniques, and selected staining procedures for whole-mount observations of reproductive structures.

Due to its formidable tools for molecular genetic studies, Arabidopsis thaliana is one of the most prominent model species in plant biology and, ...

Quantitative Whole-mount Immunofluorescence Analysis of Cardiac Progenitor Populations in Mouse Embryos

The use of ever-advancing imaging techniques has contributed broadly to our increased understanding of embryonic development. Pre-implantation development and organogenesis are two areas of research that have benefitted greatly from these advances, due to the high quality of data that can be obtained directly from imaging pre-implantation embryos or ex vivo organs. While pre-implantation embryos have yielded data with especially high spatial resolution, later stages have been less amenable to three-dimensional reconstruction. Obtaining high-quality 3D or volumetric data for known embryonic structures in combination with fate mapping or genetic lineage tracing will allow for a more comprehensive analysis of the morphogenetic events taking place during embryogenesis.
This protocol describes a whole-mount immunofluorescence approach that allows for the labeling, visualization, and quantification of progenitor cell populations within the developing cardiac crescent, a key structure formed during heart development. The approach is designed in such a way that both cell- and tissue-level information can be obtained. Using confocal microscopy and image processing, this protocol allows for three-dimensional spatial reconstruction of the cardiac crescent, thereby providing the ability to analyze the localization and organization of specific progenitor populations during this critical phase of heart development. Importantly, the use of reference antibodies allows for successive masking of the cardiac crescent and subsequent quantitative measurements of areas within the crescent. This protocol will not only enable a detailed examination of early heart development, but with adaptations should be applicable to most organ systems in the gastrula to early somite stage mouse embryo.

Here, we describe a protocol for whole mount immunofluorescence and image-based quantitative volumetric analysis of early stage mouse embryos. We present this technique as a powerful approach to qualitatively and quantitatively assess cardiac structures during development, and propose that it may be widely adaptable to other organ systems.

The use of ever-advancing imaging techniques has contributed broadly to our increased understanding of embryonic development. Pre-implantation development ...

Whole Mount Immunofluorescence and Follicle Quantification of Cultured Mouse Ovaries

Research in the field of mammalian reproductive biology often involves evaluating the overall health of ovaries and testes. Specifically, in females, ovarian fitness is often assessed by visualizing and quantifying follicles and oocytes. Because the ovary is an opaque three-dimensional tissue, traditional approaches require laboriously slicing the tissue into numerous serial sections in order to visualize cells throughout the entire organ. Furthermore, because quantification by this method typically entails scoring only a subset of the sections separated by the approximate diameter of an oocyte, it is prone to inaccuracy. Here, a protocol is described that instead utilizes whole organ tissue clearing and immunofluorescence staining of mouse ovaries to visualize follicles and oocytes. Compared to more traditional approaches, this protocol is advantageous for visualizing cells within the ovary for numerous reasons: 1) the ovary remains intact throughout sample preparation and processing; 2) small ovaries, which are difficult to section, can be examined with ease; 3) cellular quantification is more readily and accurately achieved; and 4) the whole organ imaged.

Here, we present a protocol to quantify follicles in cultured ovaries of young mice without serial sectioning. Using whole organ immunofluorescence and tissue clearing, physical sectioning is replaced with optical sectioning. This method of sample preparation and visualization maintains organ integrity and facilitates automated quantification of specific cells.

Research in the field of mammalian reproductive biology often involves evaluating the overall health of ovaries and testes. Specifically, in females, ...

Organotypic Culture Method to Study the Development Of Embryonic Chicken Tissues

The embryonic chicken is commonly used as a reliable model organism for vertebrate development. Its accessibility and short incubation period makes it ideal for experimentation. Currently, the study of these developmental pathways in the chicken embryo is conducted by applying inhibitors and drugs at localized sites and at low concentrations using a variety of methods. In vitro tissue&#160;culturing is a technique that enables the study of tissues separated from the host organism, while simultaneously bypassing many of the physical limitations present when working with whole embryos, such as the susceptibility of embryos to high doses of potentially lethal chemicals. Here, we present an organotypic culturing protocol for culturing the embryonic chicken half head in vitro, which presents new opportunities for the examination of developmental processes beyond the currently established methods.

Here, we present an organotypic culturing protocol to grow embryonic chicken organs in vitro. Using this method, the development of embryonic chicken tissue can be studied, while maintaining a high degree of control over the culture environment.

The embryonic chicken is commonly used as a reliable model organism for vertebrate development. Its accessibility and short incubation period makes it ...

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).

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

Analysis of Cardiac Chamber Development During Mouse Embryogenesis Using Whole Mount Epifluorescence

The goal of this protocol is to describe a method for the dissection of mouse embryos and visualization of embryonic mouse ventricular chambers during heart development using ventricular specific fluorescent reporter knock-in mice (MLC-2v-tdTomato mice). Heart development involves a linear heart tube formation, the heart tube looping, and four chamber septation. These complex processes are highly conserved in all vertebrates. The mouse embryonic heart has been widely used for heart developmental studies. However, due to their extremely small size, dissecting mouse embryonic hearts is technically challenging. In addition, visualization of cardiac chamber formation often needs in situ hybridization, beta-galactosidase staining using LacZ reporter mice, or immunostaining of sectioned embryonic hearts. Here, we describe how to dissect mouse embryonic hearts and directly visualize ventricular chamber formation of MLC-2v-tdTomato mice using whole mount epifluorescent microscopy. With this method, it is possible to directly examine heart tube formation and looping, and four chamber formation without further experimental manipulation of mouse embryos. Although the MLC-2v-tdTomato reporter knock-in mouse line is used in this protocol as an example, this protocol can be applied to other heart-specific fluorescent reporter transgenic mouse lines.

We present the protocols to examine mouse heart development using whole mount epifluorescent microscopy on mouse embryos dissected from ventricular specific MLC-2v-tdTomato reporter knock-in mice. This method allows us to directly visualize each stage of the ventricular formation during mouse heart development without labor-intensive histochemical methods.

The goal of this protocol is to describe a method for the dissection of mouse embryos and visualization of embryonic mouse ventricular chambers during ...

Generation of Organoids from Mouse Extrahepatic Bile Ducts

Cholangiopathies, which affect extrahepatic bile ducts (EHBDs), include biliary atresia, primary sclerosing cholangitis, and cholangiocarcinoma. They have no effective therapeutic options. Tools to study EHBD are very limited. Our purpose was to develop an organ-specific, versatile, adult stem cell-derived, preclinical cholangiocyte model that can be easily generated from wild type and genetically engineered mice. Thus, we report on the novel technique of developing an EHBD organoid (EHBDO) culture system from adult mouse EHBDs. The model is cost-efficient, able to be readily analyzed, and has multiple downstream applications. Specifically, we describe the methodology of mouse EHBD isolation and single cell dissociation, organoid culture initiation, propagation, and long-term maintenance and storage. This manuscript also describes EHBDO processing for immunohistochemistry, fluorescent microscopy, and mRNA abundance quantitation by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). This protocol has significant advantages in addition to producing EHBD-specific organoids. The use of a conditioned medium from L-WRN cells significantly reduces the cost of this model. The use of mouse EHBDs provides almost unlimited tissue for culture generation, unlike human tissue. Generated mouse EHBDOs contain a pure population of epithelial cells with markers of endodermal progenitor and differentiated biliary cells. Cultured organoids maintain homogenous morphology through multiple passages and can be recovered after a long-term storage period in liquid nitrogen. The model allows for the study of biliary progenitor cell proliferation, can be manipulated pharmacologically, and may be generated from genetically engineered mice. Future studies are needed to optimize culture conditions in order to increase plating efficiency, evaluate functional cell maturity, and direct cell differentiation. Development of co-culture models and a more biologically neutral extracellular matrix are also desirable.

This protocol describes the production of a mouse extrahepatic bile duct 3-dimensional organoid system. These biliary organoids can be maintained in culture to study cholangiocyte biology. Biliary organoids express markers of both progenitor and biliary cells and are composed of polarized epithelial cells.

Cholangiopathies, which affect extrahepatic bile ducts (EHBDs), include biliary atresia, primary sclerosing cholangitis, and cholangiocarcinoma. They have ...