This work was supported bythe American Pediatric Surgical Association Foundation Award (AG) and the National Institutes of Health K08DK098271 (AG).

The University of Wisconsin Animal Care and Use Committee approved all procedures.
1. Preparation of Solutions
<ol>
	<li>Use 1x phosphate buffered saline (PBS) as dissection buffer and rinsing solution.</li>
	<li>Prepare 30% sucrose by weighing 30 g of sucrose and place into a bottle. Add 99 ml of 1x PBS and add 1 ml 10% sodium azide. Mix thoroughly until all of the sucrose is dissolved. Store at 4 &#176;C until required.</li>
	<li>Prepare Blocking solution by mixing 1x PBS, 3% bovine serum albumin (BSA) and 0.1% Triton-X-100. Mix thoroughly and store in the fridge until needed.</li>
	<li>Prepare 8% paraformaldehyde (PFA) solution in 1x PBS by weighing the appropriate amount of PFA into 1x PBS and then incubate at 65 &#176;C until it is completely dissolved. Store in 25 ml aliquots in the -20 &#176;C freezer until needed. Dilute to 4% PFA in 1x PBS on the day of use.</li>
</ol>
2. Embryo and Gut Dissection
<ol>
	<li>In accordance with Institutional Animal Care and Use Committee approved protocols, euthanize timed pregnant mouse and transfer the uterus into a 60 mm Petri dish containing ice cold 1x PBS.</li>
	<li>Under a dissection microscope using sharp scissors, cut the uterine wall open to expose the embryos. Remove the embryos from the uterus and place into a clean 60 mm Petri dish containing ice cold 1x PBS.</li>
	<li>Euthanize each embryo by decapitation in ice-cold 1x PBS. If you are using transgenic mice containing fluorescent proteins, under fluorescence illumination, identify the positive transgenic embryos.</li>
	<li>Dissect the GI tract from each embryo using a dissection microscope. Using fine forceps, orient the embryo such that the left side is facing upwards and the right side is against the bottom of the Petri dish. Remove the upper body wall from the embryo to expose the internal organs. Insert fine forceps between the dorsal body wall and the internal organs. Cross the forceps against each other in a scissor-like cutting action to remove the internal organs from the embryo.</li>
	<li>Further sub-dissect the GI tract away from the surrounding organs and then place each GI tract into a 1.5 ml microcentrifuge tube containing ice-cold 1x PBS.</li>
</ol>
3. Fixation of GI Tracts
<ol>
	<li>Rinse each GI tract 3 times with ice-cold 1x PBS and then replace with 4% PFA. Fix the GI tracts in the 1.5 ml microcentrifuge tubes on a rocking platform at RT&#160;for 1.5 hr. Rinse the GI tracts 3 times for 5 min at RT and then for 1 hr on the rocking platform. At this stage, store the GI tracts at 4 &#176;C in 30% sucrose in 1x PBS containing 0.1% sodium azide until needed. 
	NOTE: Alternatively, store the embryos in 30% sucrose for up to one year without any effect on the integrity of the tissues. Storage of the samples in 30% sucrose allows later processing of the samples either for immunostaining or into OCT for cryo-sectioning. Alternatively, proceed with the immunostaining protocol detailed below.</li>
</ol>
4. Immunostaining Protocol
<ol>
	<li>If samples have been stored in 30% sucrose, rinse them 3 times for 20 min in 1x PBS on a rocking platform.</li>
	<li>Place the GI tracts into blocking solution on a rocking platform for 1h at RT.</li>
	<li>Remove the blocking solution and incubate the GI tracts with the appropriate amount of primary antibodies diluted in blocking solution for either 4 hr at RT or O/N&#160;at 4 &#176;C on a rocking platform. Use 1:1,000 dilution of human anti-Hu antibody (serum obtained from patient), 1:1,000 dilution of chicken anti-green fluorescent protein (GFP) antibody and 1:100 dilution of goat anti-ChAT antibody. 
	NOTE: We utilize a human anti-Hu antibody that was obtained locally from a patient, however, anti-Hu antibodies are commercially available, for example, mouse anti-Hu, (use at 1:500 dilution).</li>
	<li>Rinse the GI tracts in 1x PBS 3 times for 5 min and then for 1 hr at RT on a rocking platform.</li>
	<li>Replace the 1x PBS with secondary antibodies diluted 1:500 in blocking solution on a rocking platform for either 4 hr at RT or O/N&#160;at 4 &#176;C. Use donkey anti-human amine-reactive dye such as Dylight, donkey anti-chicken Cy2 and donkey anti-goat Cy5. If using the mouse anti-Hu antibody then use a 1:500 dilution of donkey anti-mouse amine-reactive dye 405. 
	NOTE: The intensity of the endogenous GFP and tdTomato expression and the clarity of immunostaining increase with developmental age. We typically immunostain embryonic guts individually in 0.2 ml tubes with 150 &#956;l of staining solution in order to reduce the volume of antibody used and also to ensure efficient staining of the tissue.</li>
	<li>Rinse the GI tracts in 1x PBS 3 times for 5 min and then for 1 hr at RT on a rocking platform.</li>
	<li>Place a few drops of fluorescence mounting medium with DAPI onto a glass slide. Immerse the GI tract into the fluorescence mounting medium and add a cover glass directly on top of the tissue. The fluorescence mounting medium -G is a water-soluble compound that provides a semi-permanent seal. 
	NOTE: Use fluorescence mounting medium such as Vectashield which is a glycerol based mounting medium that prevents fading and photobleaching of antibodies. Both of these products enable tissues to be stored for long periods of time at 4 &#176;C.</li>
	<li>Capture images of each of fluorophore using a confocal microscope. Use excitation wavelengths for fluorophores and filters employed presented in Table 3.</li>
	<li>Perform computer-aided image analysis using appropriate software depending on the type of confocal used to capture images.</li>
</ol>

<ol><li>Gershon, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Developmental+determinants+of+the+independence+and+complexity+of+the+enteric+nervous+system%5BTitle%5D)+AND+%22Trends+Neurosci%22%5BJournal%5D)">Developmental determinants of the independence and complexity of the enteric nervous system.</a> Trends Neurosci. 33 (10), 446-456 (2010).</li>
<li>Amiel, J., Sproat-Emison, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Hirschsprung+disease%2C+associated+syndromes+and+genetics%3A+a+review%5BTitle%5D)+AND+%22J+Med+Genet%22%5BJournal%5D)">Hirschsprung disease, associated syndromes and genetics: a review.</a> J Med Genet. 45 (1), 1-14 (2008).</li>
<li>Erickson, C. S., Barlow, A. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Colonic+enteric+nervous+system+analysis+during+parenteral+nutrition%5BTitle%5D)+AND+%22J+Surg+Res%22%5BJournal%5D)">Colonic enteric nervous system analysis during parenteral nutrition.</a> J Surg Res. 184 (1), 132-137 (2013).</li>
<li>Erickson, C. S., Zaitoun, I., Haberman, K. M., Gosain, A., Druckenbrod, N. R., Epstein, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Sacral+neural+crest-derived+cells+enter+the+aganglionic+colon+of+Ednrb%28-%2F-%29+mice+along+extrinsic+nerve+fibers%5BTitle%5D)+AND+%22J+Comp+Neurol%22%5BJournal%5D)">Sacral neural crest-derived cells enter the aganglionic colon of Ednrb(-/-) mice along extrinsic nerve fibers.</a> J Comp Neurol. 20 (3), 620-632 (2011).</li>
<li>Zaitoun, I., Erickson, C. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Altered+neuronal+density+and+neurotransmitter+expression+in+the+ganglionated+region+of+Ednrb+null+mice%3A+implications+for+Hirschsprung%27s+disease%5BTitle%5D)+AND+%22Neurogastroenterol+Motil%22%5BJournal%5D)">Altered neuronal density and neurotransmitter expression in the ganglionated region of Ednrb null mice: implications for Hirschsprung's disease.</a> Neurogastroenterol Motil. , (2013).</li>
<li>Margolis, K. G., Stevanovic, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Enteric+neuronal+density+contributes+to+the+severity+of+intestinal+inflammation%5BTitle%5D)+AND+%22Gastroenterology%22%5BJournal%5D)">Enteric neuronal density contributes to the severity of intestinal inflammation.</a> Gastroenterology. 141 (2), 588-598 (2011).</li>
<li>Qu, Z. -D., Thacker, M., Castelucci, P., Bagyánszki, M., Epstein, M. L., Furness, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Immunohistochemical+analysis+of+neuron+types+in+the+mouse+small+intestine%5BTitle%5D)+AND+%22Cell+Tissue+Res%22%5BJournal%5D)">Immunohistochemical analysis of neuron types in the mouse small intestine.</a> Cell Tissue Res. 334 (2), 147-161 (2008).</li>
<li>Bian, X. -C., Bornstein, J. C., Bertrand, P. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nicotinic+transmission+at+functionally+distinct+synapses+in+descending+reflex+pathways+of+the+rat+colon%5BTitle%5D)+AND+%22Neurogastroenterol+Motil%22%5BJournal%5D)">Nicotinic transmission at functionally distinct synapses in descending reflex pathways of the rat colon.</a> Neurogastroenterol Motil. 15 (2), 161-171 (2003).</li>
<li>Johnson, C. D., Epstein, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Monoclonal+antibodies+and+polyvalent+antiserum+to+chicken+choline+acetyltransferase%5BTitle%5D)+AND+%22J+Neurochem%22%5BJournal%5D)">Monoclonal antibodies and polyvalent antiserum to chicken choline acetyltransferase.</a> J Neurochem. 46 (3), 968-976 (1986).</li>
<li>Tooyama, I., Kimura, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+protein+encoded+by+an+alternative+splice+variant+of+choline+acetyltransferase+mRNA+is+localized+preferentially+in+peripheral+nerve+cells+and+fibers%5BTitle%5D)+AND+%22J+Chem+Neuroanat%22%5BJournal%5D)">A protein encoded by an alternative splice variant of choline acetyltransferase mRNA is localized preferentially in peripheral nerve cells and fibers.</a> J Chem Neuroanat. 17 (4), 217-226 (2000).</li>
<li>Koga, T., Bellier, J. -P., Kimura, H., Tooyama, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Immunoreactivity+for+Choline+Acetyltransferase+of+Peripheral-Type+%28pChAT%29+in+the+Trigeminal+Ganglion+Neurons+of+the+Non-Human+Primate+Macaca+fascicularis%5BTitle%5D)+AND+%22Acta+histochemica+et+cytochemica%22%5BJournal%5D)">Immunoreactivity for Choline Acetyltransferase of Peripheral-Type (pChAT) in the Trigeminal Ganglion Neurons of the Non-Human Primate Macaca fascicularis.</a> Acta histochemica et cytochemica. 46 (2), 59-64 (2013).</li>
<li>Sang, Q., Young, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+identification+and+chemical+coding+of+cholinergic+neurons+in+the+small+and+large+intestine+of+the+mouse%5BTitle%5D)+AND+%22Anat+Rec%22%5BJournal%5D)">The identification and chemical coding of cholinergic neurons in the small and large intestine of the mouse.</a> Anat Rec. 251 (2), 185-199 (1998).</li>
<li>Lei, J., Howard, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Targeted+deletion+of+Hand2+in+enteric+neural+precursor+cells+affects+its+functions+in+neurogenesis%2C+neurotransmitter+specification+and+gangliogenesis%2C+causing+functional+aganglionosis%5BTitle%5D)+AND+%22Development+%28Cambridge%2C+England%29%22%5BJournal%5D)">Targeted deletion of Hand2 in enteric neural precursor cells affects its functions in neurogenesis, neurotransmitter specification and gangliogenesis, causing functional aganglionosis.</a> Development (Cambridge, England). 138 (21), 4789-4800 (2011).</li>
<li>Erickson, C. S., Lee, S. J., Barlow-Anacker, A. J., Druckenbrod, N. R., Epstein, M. L., Gosain, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Appearance+of+cholinergic+myenteric+neurons+during+enteric+nervous+system+development%3A+comparison+of+different+ChAT+fluorescent+mouse+reporter+lines%5BTitle%5D)+AND+%22Neurogastroenterol+Motil%22%5BJournal%5D)">Appearance of cholinergic myenteric neurons during enteric nervous system development: comparison of different ChAT fluorescent mouse reporter lines.</a> Neurogastroenterol Motil. 26 (6), 874-884 (2014).</li>
<li>Teitelbaum, D. H., Caniano, D. A., Qualman, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+pathophysiology+of+Hirschsprung%27s-associated+enterocolitis%3A+importance+of+histologic+correlates%5BTitle%5D)+AND+%22J+Pediatr+Surg%22%5BJournal%5D)">The pathophysiology of Hirschsprung's-associated enterocolitis: importance of histologic correlates.</a> J Pediatr Surg. 24 (12), 1271-1277 (1989).</li>
<li>Aslam, A., Spicer, R. D., Corfield, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Children+with+Hirschsprung%27s+disease+have+an+abnormal+colonic+mucus+defensive+barrier+independent+of+the+bowel+innervation+status%5BTitle%5D)+AND+%22J+Pediatr+Surg%22%5BJournal%5D)">Children with Hirschsprung's disease have an abnormal colonic mucus defensive barrier independent of the bowel innervation status.</a> J Pediatr Surg. 32 (8), 1206-1210 (1997).</li>
<li>Puig, I., Champeval, D., De Santa Barbara, P., Jaubert, F., Lyonnet, S., Larue, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Deletion+of+Pten+in+the+mouse+enteric+nervous+system+induces+ganglioneuromatosis+and+mimics+intestinal+pseudoobstruction%5BTitle%5D)+AND+%22J+Clin+Invest%22%5BJournal%5D)">Deletion of Pten in the mouse enteric nervous system induces ganglioneuromatosis and mimics intestinal pseudoobstruction.</a> J Clin Invest. 119 (12), 3586-3596 (2009).</li>
</ol>

The authors have nothing to disclose.

Our laboratory and others have shown that intestinal defects in HSCR are not restricted to the aganglionic colon but extended proximally, even into the ganglionated small intestine5,15,16. These alterations include changes in ENS neuronal density and neurotransmitter phenotype and may account for dysmotility that has been observed in patients with HSCR. We have utilized the above techniques in our efforts to understand the determinants of ENS formation. Specifically, these techniques have been employed to visu...

A functioning Enteric Nervous System (ENS), which controls motility, nutrient absorption, and local blood flow, is essential to life1. The ENS is formed by neural crest cells (NCC) that proliferate, migrate and colonize the gut, where they differentiate into ganglia containing neurons and glial cells. Hirschsprung&#8217;s Disease (HSCR, Online Mendelian Inheritance in Man), a multigeneic congenital disorder with an incidence of 1 in 4,000 live births, can be considered the prototypic disease for studying disrupted ENS formation. In HSCR, NCC fail to migrate to and colonize variable lengths of the distal hindgut2. Additionally, other common gastrointestinal (GI) developmental defects in the pediatric population, such as anorectal malformations, intestinal atresias, and motility disorders are associated with disturbances in basic ENS functions, and are likely associated with subtle, underappreciated, anatomic changes and functional changes in the ENS3-6. Therefore, techniques that allow us to understand the developmental determinants of ENS formation may shed light on the pathogenesis and potential treatment of pediatric GI tract disorders.
Following migration and colonization, NCC differentiates into neurons with markers specific for their neurotransmitter phenotype. Cholinergic neurons comprise approximately 60% of enteric neurons7, and can be detected by staining for choline acetyltransferase (ChAT), the synthesizing enzyme for the excitatory neurotransmitter acetylcholine. Historically, attempts to visualize cholinergic neurons were confounded by differing antigen specificity of antibodies directed against central nervous system (CNS) ChAT versus peripheral nervous system (PNS) ChAT8-10. However, antibodies directed against placental ChAT recognize both central and peripheral ChAT11-13, and we have recently described techniques that allow for visualization of ENS cholinergic neurons with high sensitivity earlier in development than has been achieved with ChAT reporter lines14.
Here, we present a technique for dissecting, fixing and immunostaining of the murine embryonic GI tract to visualize ENS neurotransmitter expression in neurons. For these studies, we have utilized ChAT-Cre mice mated with R26R:floxSTOP:tdTomato animals to produce ChAT-Cre;R26R:floxSTOP:tdTomato mice (defined as ChAT-Cre tdTomato throughout the manuscript). These animals were then mated with homozygous ChAT-GFP reporter mice, to obtain mice expressing both fluorescent reporters that detect ChAT expression14. These two reporter animals are on a C57BL/6J background and are commercially available (Jackson Laboratories, Bar Harbor, ME).

<table><tbody><tr><td>Phosphate buffered saline</td><td>Oxoid</td><td>BR0014G</td><td></td></tr><tr><td>Sucrose</td><td>Fisher</td><td>S2</td><td></td></tr><tr><td>Sodium azide</td><td>Fisher</td><td>BP9221</td><td></td></tr><tr><td>Bovine serum albumin</td><td>Fisher</td><td>BP1605</td><td></td></tr><tr><td>Triton X-100</td><td>Sigma</td><td>X100</td><td></td></tr><tr><td>Paraformaldehyde</td><td>Sigma</td><td>158127</td><td></td></tr><tr><td>60 mm Petri dishes</td><td>Fisher</td><td>FB0875713A</td><td></td></tr><tr><td>Fluorescence microscope</td><td>Nikon</td><td>SMZ-18 stereoscope</td><td></td></tr><tr><td>Dissection microscope</td><td>Nikon</td><td>SMZ-18 stereoscope</td><td></td></tr><tr><td>Fine forceps</td><td>Fine science tools</td><td>11252-20</td><td></td></tr><tr><td>1.5 ml Eppendorf tubes</td><td>VWR</td><td>20170-038</td><td></td></tr><tr><td>Fluoromount-G</td><td>SouthernBiotech, Birmingham, AL</td><td>0100-01</td><td></td></tr><tr><td>Glass slides</td><td>Fisher</td><td>12-550-15</td><td></td></tr><tr><td>Cover glass</td><td>VWR</td><td>16004-330</td><td></td></tr><tr><td>Confocal microscope</td><td>Nikon</td><td>Nikon A1</td><td></td></tr><tr><td>Nikon Elements</td><td>Nikon</td><td></td><td></td></tr></tbody></table>

immunostaining to visualize murine enteric nervous system development

The enteric nervous system is formed by neural crest cells that proliferate, migrate and colonize the gut. Following colonization, neural crest cells must then differentiate into neurons with markers specific for their neurotransmitter phenotype. Cholinergic neurons, a major neurotransmitter phenotype in the enteric nervous system, are identified by staining for choline acetyltransferase (ChAT), the synthesizing enzyme for acetylcholine. Historical efforts to visualize cholinergic neurons have been hampered by antibodies with differing specificities to central nervous system versus peripheral nervous system ChAT. We and others have overcome this limitation by using an antibody against placental ChAT, which recognizes both central and peripheral ChAT, to successfully visualize embryonic enteric cholinergic neurons. Additionally, we have compared this antibody to genetic reporters for ChAT and shown that the antibody is more reliable during embryogenesis. This protocol describes a technique for dissecting, fixing and immunostaining of the murine embryonic gastrointestinal tract to visualize enteric nervous system neurotransmitter expression.

We have previously described the generation of mice expressing both GFP and tdTomato fluorescent reporters that detect ChAT expression14. Briefly, ChAT-Cre mice were mated with R26R:floxSTOP:tdTomato animals to produce ChAT-Cre;R26R:floxSTOP:tdTomato mice (called ChAT-Cre tdTomato). These animals were then mated with homozygous ChAT-GFP reporter mice. Embryos were isolated and tissues were dissected prior to being fixed and immunostained as above, with the antibodie...

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Immunostaining to Visualize Murine Enteric Nervous System Development | Developmental Biology | Video

Immunostaining to Visualize Murine Enteric Nervous System Development

The enteric nervous system is formed by neural crest cells that proliferate, migrate and colonize the gut. Neural crest cells differentiate into neurons with markers specific for their neurotransmitter phenotype. This protocol describes a technique for dissecting, fixing and immunostaining of the murine embryonic gastrointestinal tract to visualize enteric nervous system neurotransmitter expression.

The enteric nervous system is formed by neural crest cells that proliferate, migrate and colonize the gut. Following colonization, neural crest cells must ...

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11.4K Views.  University of Wisconsin School of Medicine and Public Health. The enteric nervous system is formed by neural crest cells that proliferate, migrate and colonize the gut. Neural crest cells differentiate into neurons with markers specific for their neurotransmitter phenotype. This protocol describes a technique for dissecting, fixing and immunostaining of the murine embryonic gastrointestinal tract to visualize enteric nervous system neurotransmitter expression.

Video: Immunostaining to Visualize Murine Enteric Nervous System Development

Multimodal Imaging of Stem Cell Implantation in the Central Nervous System of Mice

During the past decade, stem cell transplantation has gained increasing interest as primary or secondary therapeutic modality for a variety of diseases, both in preclinical and clinical studies. However, to date results regarding functional outcome and/or tissue regeneration following stem cell transplantation are quite diverse. Generally, a clinical benefit is observed without profound understanding of the underlying mechanism(s)1. Therefore, multiple efforts have led to the development of different molecular imaging modalities to monitor stem cell grafting with the ultimate aim to accurately evaluate survival, fate and physiology of grafted stem cells and/or their micro-environment. Changes observed in one or more parameters determined by molecular imaging might be related to the observed clinical effect. In this context, our studies focus on the combined use of bioluminescence imaging (BLI), magnetic resonance imaging (MRI) and histological analysis to evaluate stem cell grafting.
BLI is commonly used to non-invasively perform cell tracking and monitor cell survival in time following transplantation2-7, based on a biochemical reaction where cells expressing the Luciferase-reporter gene are able to emit light following interaction with its substrate (e.g. D-luciferin)8, 9. MRI on the other hand is a non-invasive technique which is clinically applicable10 and can be used to precisely locate cellular grafts with very high resolution11-15, although its sensitivity highly depends on the contrast generated after cell labeling with an MRI contrast agent. Finally, post-mortem histological analysis is the method of choice to validate research results obtained with non-invasive techniques with highest resolution and sensitivity. Moreover end-point histological analysis allows us to perform detailed phenotypic analysis of grafted cells and/or the surrounding tissue, based on the use of fluorescent reporter proteins and/or direct cell labeling with specific antibodies.
In summary, we here visually demonstrate the complementarities of BLI, MRI and histology to unravel different stem cell- and/or environment-associated characteristics following stem cell grafting in the CNS of mice. As an example, bone marrow-derived stromal cells, genetically engineered to express the enhanced Green Fluorescent Protein (eGFP) and firefly Luciferase (fLuc), and labeled with blue fluorescent micron-sized iron oxide particles (MPIOs), will be grafted in the CNS of immune-competent mice and outcome will be monitored by BLI, MRI and histology (Figure 1).

This article describes an optimized sequence of events for multimodal imaging of cellular grafts in rodent brain using: (i) in vivo bioluminescence and magnetic resonance imaging, and (ii) post mortem histological analysis. Combining these imaging modalities on a single animal allows cellular graft evaluation with high resolution, sensitivity and specificity.

During the past decade, stem cell transplantation has gained increasing interest as primary or secondary therapeutic modality for a variety of diseases, ...

Neuroscience

Whole Mount Immunofluorescent Staining of the Neonatal Mouse Retina to Investigate Angiogenesis In vivo

Angiogenesis is the complex process of new blood vessel formation defined by the sprouting of new blood vessels from a pre-existing vessel network. Angiogenesis plays a key role not only in normal development of organs and tissues, but also in many diseases in which blood vessel formation is dysregulated, such as cancer, blindness and ischemic diseases. In adult life, blood vessels are generally quiescent so angiogenesis is an important target for novel drug development to try and regulate new vessel formation specifically in disease. In order to better understand angiogenesis and to develop appropriate strategies to regulate it, models are required that accurately reflect the different biological steps that are involved. The mouse neonatal retina provides an excellent model of angiogenesis because arteries, veins and capillaries develop to form a vascular plexus during the first week after birth. This model also has the advantage of having a two-dimensional (2D) structure making analysis straightforward compared with the complex 3D anatomy of other vascular networks. By analyzing the retinal vascular plexus at different times after birth, it is possible to observe the various stages of angiogenesis under the microscope. This article demonstrates a straightforward procedure for analyzing the vasculature of a mouse retina using fluorescent staining with isolectin and vascular specific antibodies.

Whole Mount Immunofluorescent Staining of the Neonatal Mouse Retina to Investigate Angiogenesis In vivo

The neonatal murine retina provides a well characterized physiological model of angiogenesis, which permits investigations of the roles of different genes or drugs that modulate angiogenesis in an in vivo context. Immunofluorescent staining to accurately visualize the vascular plexus is pivotal to the success of these types of studies.

Angiogenesis  is the complex process of new blood vessel formation defined by the sprouting  of new blood vessels from a pre-existing vessel network. ...

An In-vitro Preparation of Isolated Enteric Neurons and Glia from the Myenteric Plexus of the Adult Mouse

The enteric nervous system is a vast network of neurons and glia running the length of the gastrointestinal tract that functionally controls gastrointestinal motility. A procedure for the isolation and culture of a mixed population of neurons and glia from the myenteric plexus is described. The primary cultures can be maintained for over 7 days, with connections developing among the neurons and glia. The longitudinal muscle strip with the attached myenteric plexus is stripped from the underlying circular muscle of the mouse ileum or colon and subjected to enzymatic digestion. In sterile conditions, the isolated neuronal and glia population are preserved within the pellet following centrifugation and plated on coverslips. Within 24-48 hr, neurite outgrowth occurs and neurons can be identified by pan-neuronal markers. After two days in culture, isolated neurons fire action potentials as observed by patch clamp studies. Furthermore, enteric glia can also be identified by GFAP staining. A network of neurons and glia in close apposition forms within 5 - 7 days. Enteric neurons can be individually and directly studied using methods such as immunohistochemistry, electrophysiology, calcium imaging, and single-cell PCR. Furthermore, this procedure can be performed in genetically modified animals. This methodology is simple to perform and inexpensive. Overall, this protocol exposes the components of the enteric nervous system in an easily manipulated manner so that we may better discover the functionality of the ENS in normal and disease states.

An In-vitro Preparation of Isolated Enteric Neurons and Glia from the Myenteric Plexus of the Adult Mouse

We demonstrate a cell culture protocol for the direct study of neuronal and glial components of the enteric nervous system. A neuron/glia mixed culture on coverslips is prepared from the myenteric plexus of adult mouse providing the ability to examine individual neuron and glia function by electrophysiology, immunohistochemical, etc.

The enteric nervous system is a vast network of neurons and glia running the length of the gastrointestinal tract that functionally controls ...

A Quantitative Cell Migration Assay for Murine Enteric Neural Progenitors

Neural crest cells (NCC) are a transient and multipotent cell population that originates from the dorsal neural tube and migrates extensively throughout the developing vertebrate embryo. In addition to providing peripheral glia and neurons, NCC generate melanocytes as well as most of the cranio-facial skeleton. NCC migration and differentiation is controlled by a combination of their axial origin along the neural tube and their exposure to regionally distinct extracellular cues. Such contribution of extracellular ligands is especially evident during the formation of the enteric nervous system (ENS), a complex interconnected network of neural ganglia that locally controls (among other things) gut muscle movement and intestinal motility. Most of the ENS is derived from a small initial pool of NCC that undertake a long journey in order to colonize - in a rostral to caudal fashion - the entire length of the prospective gut. Among several signaling pathways known to influence enteric NCC colonization, GDNF/RET signaling is recognized as the most important. Indeed, spatiotemporally controlled secretion of the RET ligand GDNF by the gut mesenchyme is chiefly responsible for the attraction and guidance of RET-expressing enteric NCC to and within the embryonic gut. Here, we describe an ex vivo cell migration assay, making use of a transgenic mouse line possessing fluorescently labeled NCC, which allows precise quantification of enteric NCC migration potential in the presence of various growth factors, including GDNF.

We present an ex vivo cell migration assay that allows precise quantification of enteric neural crest cell migration potential in the presence of various growth factors.

Neural crest cells (NCC) are a transient and multipotent cell population that originates from the dorsal neural tube and migrates extensively throughout ...

In Situ Ca2+ Imaging of the Enteric Nervous System

Reflex behaviors of the intestine are controlled by the enteric nervous system (ENS). The ENS is an integrative network of neurons and glia in two ganglionated plexuses housed in the gut wall. Enteric neurons and enteric glia are the only cell types within the enteric ganglia. The activity of enteric neurons and glia is responsible for coordinating intestinal functions. This protocol describes methods for observing the activity of neurons and glia within the intact ENS by imaging intracellular calcium (Ca2+) transients with fluorescent indicator dyes. Our technical discussion focuses on methods for Ca2+ imaging in whole-mount preparations of the myenteric plexus from the rodent bowel. Bulk loading of ENS whole-mounts with a high-affinity Ca2+ indicator such as Fluo-4 permits measurements of Ca2+ responses in individual neurons or glial cells. These responses can be evoked repeatedly and reliably, which permits quantitative studies using pharmacological tools. Ca2+ responses in cells of the ENS are recorded using a fluorescence microscope equipped with a cooled charge-coupled device (CCD) camera. Fluorescence measurements obtained using Ca2+ imaging in whole-mount preparations offer a straightforward means of characterizing the mechanisms and potential functional consequences of Ca2+ responses in enteric neurons and glial cells.

In Situ Ca2+ Imaging of the Enteric Nervous System

The enteric nervous system (ENS) is a network of neurons and glia located in the gut wall that controls intestinal reflexes. This protocol describes methods for recording the activity of enteric neurons and glia in live preparations of ENS using Ca2+ imaging.

Reflex behaviors of the intestine are controlled by the enteric nervous system (ENS). The ENS is an integrative network of neurons and glia in two ...

Embryonic Mouse Brain Mixed Cell Cultures to Study Infection and Innate Immunity

Establishing Mixed Neuronal and Glial Cell Cultures from Embryonic Mouse Brains to Study Infection and Innate Immunity

Models of the central nervous system (CNS) must recapitulate the complex network of interconnected cells found in vivo. The CNS consists primarily of neurons, astrocytes, oligodendrocytes, and microglia. Due to increasing efforts to replace and reduce animal use, a variety of in vitro cell culture systems have been developed to explore innate cell properties, which allow the development of therapeutics for CNS infections and pathologies. Whilst certain research questions can be addressed by human-based cell culture systems, such as (induced) pluripotent stem cells, working with human cells has its own limitations with regard to availability, costs, and ethics. Here, we describe a unique protocol for isolating and culturing cells from embryonic mouse brains. The resulting mixed neural cell cultures mimic several cell populations and interactions found in the brain in vivo. Compared to current equivalent methods, this protocol more closely mimics the characteristics of the brain and also garners more cells, thus allowing for more experimental conditions to be investigated from one pregnant mouse. Further, the protocol is relatively easy and highly reproducible. These cultures have been optimized for use at various scales, including 96-well based high throughput screens, 24-well microscopy analysis, and 6-well cultures for flow cytometry and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. This culture method is a powerful tool to investigate infection and immunity within the context of some of the complexity of the CNS with the convenience of in vitro methods.

Author Spotlight: Establishing Mixed Neuronal and Glial Cell Cultures from Embryonic Mouse Brains to Study Infection and Innate Immunity  

This protocol presents a unique way of generating central nervous system cell cultures from embryonic day 17 mouse brains for neuro(immuno)logy research. This model can be analyzed using various experimental techniques, including RT-qPCR, microscopy, ELISA, and flow cytometry.

Models of the central nervous system (CNS) must recapitulate the complex network of interconnected cells found in vivo. The CNS consists primarily of ...

Using a Whole-mount Immunohistochemical Method to Study the Innervation of the Biliary Tract in Suncus murinus

This work describes the whole-mount immunohistochemistry staining method in detail, using neurofilament protein antibody to label the innervation of the biliary tract in Suncus murinus (S. murinus&#160;). First, the specimen was dissected from S. murinus and fixed in 4% paraformaldehyde (PFA). Second, an enzymatic treatment and potential endogenous peroxidase inactivation were performed. The specimen was then exposed to the primary antibody, anti-neurofilament protein antibody, for 3-6 days. It was then incubated with the secondary antibody conjugated with horseradish peroxidase. The color reaction was revealed by reacting the specimen with a 3,3&#39;-diaminobenzidine (DAB) substrate. This method can be applied to analyze the innervation of all visceral organs. Furthermore, this protocol can also be adapted to test other neuronal antibodies, but optimization of the antibodies should be done first. This method was originally introduced by Kuratani and Tanaka1,2,3.

Using a Whole-mount Immunohistochemical Method to Study the Innervation of the Biliary Tract in Suncus murinus

A whole-mount immunohistochemical approach, to visualize neurofilament protein expression in the extrahepatic biliary tract in Suncus murinus. is presented here. This protocol can be used to analyze the innervation of all visceral organs in S. murinus or other species.

This work describes the whole-mount immunohistochemistry staining method in detail, using neurofilament protein antibody to label the innervation of the ...

Immunofluorescence Staining for Visualizing Proliferated Neural Stem Cells in Mouse Brain Sections

Source: Quintanilla, L. J., et al. <a href="https://app.jove.com/v/59237">Assaying Circuit Specific Regulation of Adult Hippocampal Neural Precursor Cells.</a> J. Vis. Exp. (2019)
This video demonstrates the procedure for staining newly proliferated neural stem cells in brain tissue sections using EdU incorporation, followed by immunofluorescence to visualize specific proteins, enhancing the understanding of cell dynamics and proliferation.

All procedures involving animal samples have been reviewed and approved by the appropriate animal ethical review committee.
1. Immunohistochemistry

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JoVE Encyclopedia of Experiments

Neuropathology

Developmental and Pediatric Disorders

Immunofluorescent Staining of Neuronal Populations in the Embryonic Murine Gastrointestinal Tract

Source: Barlow-Anacker, A. J., et al., <a href="https://app.jove.com/v/52716">Immunostaining to Visualize Murine Enteric Nervous System Development.</a> J. Vis. Exp. (2015)
This video demonstrates the immunostaining of the embryonic murine gastrointestinal tract to visualize and analyze the neuronal population distribution using immunofluorescence and confocal microscopy.

All procedures involving animal samples have been reviewed and approved by the appropriate animal ethical review committee.
1. Immunostaining Protocol

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Immunohistochemical Staining of Nerve Fibers in the Nucleus Basalis of Meyner of the Mouse Brain

Source: Singh, P., et al. <a href="https://app.jove.com/v/60405">Stereological Estimation of Cholinergic Fiber Length in the Nucleus Basalis of Meynert of the Mouse Brain.</a> J. Vis. Exp. (2020)
This video demonstrates the immunohistochemical staining of cholinergic fibers in the nucleus basalis of the Meynert region of mouse brain sections. Sections are blocked and treated with primary against choline acetyltransferase, followed by biotinylated secondary antibodies. Avidin-biotin-peroxidase complexes are added, which bind to secondary antibodies, followed by the chromogenic substrate. Sections are then dehydrated and mounted before visualizing under the microscope.

Source: Singh, P., et al. Stereological Estimation of Cholinergic Fiber Length in the Nucleus Basalis of Meynert of the Mouse Brain. J. Vis. Exp. (2020)
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Immunostaining to Visualize Murine Enteric Nervous System Development

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