Name: whole-mount confocal microscopy for adult ear skin: a model system to study neuro-vascular branching morphogenesis and immune cell distribution
Uploaded: 2018-03-29T15:00:00
Description: Watch this Scientific Journal Video about Whole-mount Confocal Microscopy for Adult Ear Skin: A Model System to Study Neuro-vascular Branching Morphogenesis and Immune Cell Distribution at JoVE.com

We thank K. Gill for the laboratory management and technical support, J. Hawkins and the staff of National Institutes of Health (NIH) Building 50 animal facility for the assistance with mouse care, and R. Reed and F. Baldrey for administrative assistance. Thanks also to S. Motegi and M. Udey for sharing their ear skin dissection protocol, N. Burns for editorial help, and members of the Laboratory of Stem Cell and Neuro-Vascular Biology for technical help and thoughtful discussion. T. Yamazaki was supported by the Japan Society for the Promotion of Science (JSPS) NIH-KAITOKU. This work was supported by the Intramural Research Program of the National Heart, Lung, and Blood Institute (HL005702-11 to Y.M.)

All experiments in this section were performed under approval from the National Heart, Lung, and Blood Institute (NHLBI) Animal Care and Use Committee.
1. Adult Mouse Ear Skin Collection
<ol>
	<li>Euthanize adult mice by carbon dioxide (CO2) exposure in a closed chamber and then confirm the euthanasia by cervical dislocation. 
	NOTE: The experiment follows the National Institutes of Health (NIH) guideline for the euthanasia method.</li>
	<li>Dissect the ear from the base and ...

<ol>
	<li>Mukouyama, Y. S., Shin, D., Britsch, S., Taniguchi, M., Anderson, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensory+nerves+determine+the+pattern+of+arterial+differentiation+and+blood+vessel+branching+in+the+skin.">Sensory nerves determine the pattern of arterial differentiation and blood vessel branching in the skin.</a> Cell. 109, 693-705 (2002).</li><li>Mukouyama, Y. S., James, J., Nam, J., Uchida, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-mount+confocal+microscopy+for+vascular+branching+morphogenesis.">Whole-mount confocal microscopy for vascular branching morphogenesis.</a> Methods Mol Biol. 843, 69-78 (2012).</li><li>Li, W., Mukouyama, Y. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-mount+immunohistochemical+analysis+for+embryonic+limb+skin+vasculature:+a+model+system+to+study+vascular+branching+morphogenesis+in+embryo.">Whole-mount immunohistochemical analysis for embryonic limb skin vasculature: a model system to study vascular branching morphogenesis in embryo.</a> J Vis Exp. , (2011).</li><li>Yamazaki, T., 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=Tissue+Myeloid+Progenitors+Differentiate+into+Pericytes+through+TGF-beta+Signaling+in+Developing+Skin+Vasculature.">Tissue Myeloid Progenitors Differentiate into Pericytes through TGF-beta Signaling in Developing Skin Vasculature.</a> Cell Rep. 18, 2991-3004 (2017).</li><li>Mukouyama, Y. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vessel-dependent+recruitment+of+sympathetic+axons:+looking+for+innervation+in+all+the+right+places.">Vessel-dependent recruitment of sympathetic axons: looking for innervation in all the right places.</a> J Clin Invest. 124, 2855-2857 (2014).</li><li>Li, W., 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=Peripheral+nerve-derived+CXCL12+and+VEGF-A+regulate+the+patterning+of+arterial+vessel+branching+in+developing+limb+skin.">Peripheral nerve-derived CXCL12 and VEGF-A regulate the patterning of arterial vessel branching in developing limb skin.</a> Dev Cell. 24, 359-371 (2013).</li><li>Chang, H., Wang, Y., Wu, H., Nathans, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flat+mount+imaging+of+mouse+skin+and+its+application+to+the+analysis+of+hair+follicle+patterning+and+sensory+axon+morphology.">Flat mount imaging of mouse skin and its application to the analysis of hair follicle patterning and sensory axon morphology.</a> J Vis Exp. , e51749 (2014).</li><li>Salz, L., Driskell, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Horizontal+Whole+Mount:+A+Novel+Processing+and+Imaging+Protocol+for+Thick,+Three-dimensional+Tissue+Cross-sections+of+Skin.">Horizontal Whole Mount: A Novel Processing and Imaging Protocol for Thick, Three-dimensional Tissue Cross-sections of Skin.</a> J Vis Exp. , (2017).</li><li>Liakath-Ali, K., 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=Novel+skin+phenotypes+revealed+by+a+genome-wide+mouse+reverse+genetic+screen.">Novel skin phenotypes revealed by a genome-wide mouse reverse genetic screen.</a> Nat Commun. 5, 3540 (2014).</li><li>Gunawan, 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=The+methyltransferase+Ezh2+controls+cell+adhesion+and+migration+through+direct+methylation+of+the+extranuclear+regulatory+protein+talin.">The methyltransferase Ezh2 controls cell adhesion and migration through direct methylation of the extranuclear regulatory protein talin.</a> Nat Immunol. 16, 505-516 (2015).</li><li>Avci, 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=Animal+models+of+skin+disease+for+drug+discovery.">Animal models of skin disease for drug discovery.</a> Expert Opin Drug Dis. 8, 331-355 (2013).</li><li>Jin, H., He, R., Oyoshi, M., Geha, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+atopic+dermatitis.">Animal models of atopic dermatitis.</a> J Invest Dermatol. 129, 31-40 (2009).</li><li>Wagner, E. F., Schonthaler, H. B., Guinea-Viniegra, J., Tschachler, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Psoriasis:+what+we+have+learned+from+mouse+models.">Psoriasis: what we have learned from mouse models.</a> Nat Rev Rheumatol. 6, 704-714 (2010).</li><li>Nunan, R., Harding, K. G., Martin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+challenges+of+chronic+wounds:+searching+for+an+optimal+animal+model+to+recapitulate+their+complexity.">Clinical challenges of chronic wounds: searching for an optimal animal model to recapitulate their complexity.</a> Dis Model Mech. 7, 1205-1213 (2014).</li><li>O'Brien, P. D., Sakowski, S. A., Feldman, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+models+of+diabetic+neuropathy.">Mouse models of diabetic neuropathy.</a> ILAR J. 54, 259-272 (2014).</li><li>Yamazaki, T., 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=Whole-Mount+Adult+Ear+Skin+Imaging+Reveals+Defective+Neuro-Vascular++Branching+Morphogenesis+in+Obese+and+Type+2+Diabetic+Mouse+Models.">Whole-Mount Adult Ear Skin Imaging Reveals Defective Neuro-Vascular Branching Morphogenesis in Obese and Type 2 Diabetic Mouse Models.</a> Sci Rep. 8, (2018).</li></ol>

This protocol describes the whole-mount immunonohistochemical imaging of adult ear skin for the analysis of neuro-vascular structures and immune cell distribution. We believe this method has numerous experimental advantages for researchers to study branching morphogenesis and the patterning of peripheral nerves and blood vessels, as well as three-dimensional distribution of skin components including immune cells and hair follicles. The results of the imaging can be quantified using imaging softwares for further quantitat...

Skin is comprised of three layers: the epidermis, dermis and hypodermis. It has been used as a model system to study stem cell maintenance, differentiation, and morphogenesis in development as well as the regeneration, tumorigenesis, and inflammation in adult. Skin is richly vascularized and innervated such that the development of the peripheral nervous system and vascular system is well-coordinated.
We have previously demonstrated a whole-mount embryonic skin imaging technique with multiple labeling to study intact peripheral nerves and blood vessels including their cellular components1,2,3,4: sensory axons, sympathetic axons, Schwann cells in nerves, endothelial cells, pericytes, and vascular smooth muscle cells (VSMCs) in blood vessels. During the angiogenesis, a primary capillary network undergoes intensive vascular remodeling and develops into a hierarchical vascular branching network. In the developing dermis/hypodermis, arteries branch alongside peripheral sensory nerves and veins then form adjacent to the arteries. After the hierarchical vascular network is thoroughly covered with VSMCs, sympathetic nerves extend along and innervate large-diameter blood vessels1,5,6. Despite the significance in the close association between the developing nervous and vascular systems, a major question has been to address what happens to the neuro-vascular networks in various pathological situations in adults. A three-dimensional high-resolution imaging is necessary to appreciate the pathogenesis, along with anatomically recognizable branching morphogenesis and patterning.
Neuronal and vascular morphogenesis in adult mouse skin is commonly analyzed by tissue section staining. Other studies have used whole-mount imaging of the skin to visualize the peripheral nerves and blood vessels, in addition to the hair follicles, sebaceous glands, and arrector pili muscles7,8,9. However, the thickness of adult skin has made it difficult to analyze the skin over its entire depth.
In the present study, we developed a novel high-resolution whole-mount imaging of adult ear skin to overcome these challenges. Ear skin is readily accessible for dissection and subsequent whole-mount imaging of the skin over its entire depth. Thus, it is a straightforward and highly reproducible method that can be applied to compare three-dimensional architecture of peripheral nervous and vascular systems in the skin, with comprehensive quantification measurements. We demonstrated that the alignment of peripheral sensory and sympathetic nerves with large-diameter blood vessels is preserved in the adult skin. The goal of this protocol is to visualize branching morphogenesis, and the patterning of peripheral nerves and blood vessels, as well as the immune cell distribution at a cellular level in adult mouse models in various conditions such as inflammation and regeneration.

<table>
	<tbody>
		<tr>
			<td>10 x Phosphate Buffered Saline</td>
			<td>KD Medical</td>
			<td>RGE-3210</td>
			<td>PBS, without Ca2+/Mg2+</td>
		</tr>
		<tr>
			<td>Hank&#8217;s Balanced Salt Solution</td>
			<td>Gibco</td>
			<td>14025-092</td>
			<td>HBSS, with Ca2+/Mg2+</td>
		</tr>
		<tr>
			<td>16% Paraformaldehyde</td>
			<td>Electron Microscopy Sciences</td>
			<td>15710</td>
			<td>PFA, fixative, diluted in PBS</td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma</td>
			<td>X100</td>
			<td>Detergent</td>
		</tr>
		<tr>
			<td>Normal goat serum</td>
			<td>Gibco</td>
			<td>16210064</td>
			<td>Component of blocking/washing buffer</td>
		</tr>
		<tr>
			<td>Normal donkey serum</td>
			<td>Jackson Immuno research</td>
			<td>017-000-121</td>
			<td>Component of blocking/washing buffer</td>
		</tr>
		<tr>
			<td>Curved fine tweezers</td>
			<td>Dumont</td>
			<td>RS-5047</td>
			<td></td>
		</tr>
		<tr>
			<td>Curved tweezers</td>
			<td>Integra Miltex Vantage</td>
			<td>V918-782, V918-784</td>
			<td></td>
		</tr>
		<tr>
			<td>Filter Unit 0.45 mm</td>
			<td>Thermo Scientific</td>
			<td>157-0045</td>
			<td>For filtration</td>
		</tr>
		<tr>
			<td>1 mL syringe</td>
			<td>Coviden</td>
			<td>8881501400</td>
			<td>For filtration</td>
		</tr>
		<tr>
			<td>Syringe filter Unit 0.22 mm</td>
			<td>Millex-GV</td>
			<td>SLGVR04NL</td>
			<td>For filtration</td>
		</tr>
		<tr>
			<td>ProLong Gold</td>
			<td>Thermo Scientific</td>
			<td>P36934</td>
			<td>Anti-fade mounting medium</td>
		</tr>
		<tr>
			<td>Nail Polish</td>
			<td>Electron Microscopy Sciences</td>
			<td>72180</td>
			<td>For sealing</td>
		</tr>
		<tr>
			<td>Dissecting microscope</td>
			<td>Leica</td>
			<td>MZ95</td>
			<td></td>
		</tr>
		<tr>
			<td>Confocal microscope</td>
			<td>Leica</td>
			<td>TCS SP5</td>
			<td></td>
		</tr>
		<tr>
			<td>Photoshop CC 2017</td>
			<td>Adobe</td>
			<td></td>
			<td>Graphics editor software</td>
		</tr>
		<tr>
			<td>Illustrator CC 2017</td>
			<td>Adobe</td>
			<td></td>
			<td>Graphics editor software</td>
		</tr>
		<tr>
			<td>Image J</td>
			<td>NIH</td>
			<td></td>
			<td>Image processing software</td>
		</tr>
		<tr>
			<td>Anti-PECAM-1 (CD31) antibody</td>
			<td>Millipore</td>
			<td>MAB1398Z</td>
			<td>Hamster IgG, vascular endothelial cell marker, 1:300</td>
		</tr>
		<tr>
			<td>Anti-PECAM-1 (CD31) antibody</td>
			<td>BD Pharmingen</td>
			<td>553369</td>
			<td>Rat IgG2a kappa, vascular endothelial cell marker, 1:300</td>
		</tr>
		<tr>
			<td>Anti-aSMA antibody conjugated with cy-3</td>
			<td>Sigma</td>
			<td>C6198</td>
			<td>Mouse IgG2a, vascular smooth muscle cell marker, 1:500</td>
		</tr>
		<tr>
			<td>Anti-EphB1 antibody</td>
			<td>Santa Cruz</td>
			<td>sc-9319</td>
			<td>Goat polyclonal, venous endothelial cell marker, 1:100</td>
		</tr>
		<tr>
			<td>Anti-neuron-specific Class III b-tubulin (Tuj1)</td>
			<td>Abcam</td>
			<td>AB18207</td>
			<td>Tuj1, Rabbit polyclonal IgG, pan-axonal marker, 1:500</td>
		</tr>
		<tr>
			<td>Anti-Tuj1 antibody</td>
			<td>Covance</td>
			<td>MMS-435P</td>
			<td>Mouse IgG2a, pan-axonal marker, 1:500</td>
		</tr>
		<tr>
			<td>Anti-MBP antibody</td>
			<td>Abcam</td>
			<td>AB40390</td>
			<td>Rabbit polyclonal IgG, myelination marker, 1:200</td>
		</tr>
		<tr>
			<td>Anti-Tyrosine Hydroxylase antibody</td>
			<td>Chemicon</td>
			<td>AB152</td>
			<td>Rabbit polyclonal, sympathetic neuron marker, 1:500</td>
		</tr>
		<tr>
			<td>Anti-Peripherin antibody</td>
			<td>Chemicon</td>
			<td>AB1530</td>
			<td>Rabbit polyclonal, peripheral neuron marker, 1:1000</td>
		</tr>
		<tr>
			<td>Anti-CD11b antibody</td>
			<td>Bio-Rad</td>
			<td>MCA74G</td>
			<td>Rat IgG2b, inflammatory cell marker (macrophages), 1:50</td>
		</tr>
		<tr>
			<td>Anti-CD45 antibody</td>
			<td>Thermo Fisher Scientific</td>
			<td>14-0451-85</td>
			<td>Rat IgG2b kappa, pan-hematopoietic cell marker, 1:500</td>
		</tr>
		<tr>
			<td>Anti-CD3 antibody</td>
			<td>Bio-Rad</td>
			<td>MCA1477T</td>
			<td>Rat IgG1, immune cell marker, 1:100</td>
		</tr>
		<tr>
			<td>Anti-CD45R (B220) antibody</td>
			<td>Thermo Fisher Scientific</td>
			<td>14-0452</td>
			<td>Rat IgG2a kappa, inflammatory cell marker, 1:200</td>
		</tr>
		<tr>
			<td>Anti-GFP antibody</td>
			<td>Thermo Fisher Scientific</td>
			<td>A11122</td>
			<td>Rabbit polyclonal, 1:300</td>
		</tr>
		<tr>
			<td>Anti-GFP antibody</td>
			<td>Abcam</td>
			<td>Ab13970</td>
			<td>Chicken polyclonal, 1:500</td>
		</tr>
		<tr>
			<td>Anti-b-gal antibody</td>
			<td>Cappel</td>
			<td>55976</td>
			<td>Rabbit polyclonal, 1:5000</td>
		</tr>
		<tr>
			<td>Anti-RFP antibody</td>
			<td>Abcam</td>
			<td>Ab62341</td>
			<td>Rabbit polyclonal, 1:300</td>
		</tr>
		<tr>
			<td>Goat anti-rabbit IgG (H+L) Alexa 488</td>
			<td>Thermo Fisher Scientific</td>
			<td>A11034</td>
			<td>Rabbit polyclonal secondary antibody, 1:250</td>
		</tr>
		<tr>
			<td>Goat anti-hamster IgG (H+L) Alexa 647</td>
			<td>Jackson Immuno research</td>
			<td>127-605-160</td>
			<td>Hamster polyclonal secondary antibody, 1:250</td>
		</tr>
		<tr>
			<td>Goat anti-rat IgG (H+L) Alexa 594</td>
			<td>Jackson Immuno research</td>
			<td>112-585-167</td>
			<td>Rat polyclonal secondary antibody, 1:250</td>
		</tr>
		<tr>
			<td>Goat anti-mouse IgG2a Alexa 633</td>
			<td>Thermo Fisher Scientific</td>
			<td>A21136</td>
			<td>Mouse IgG2a secondary antibody, 1:250</td>
		</tr>
	</tbody>
</table>

whole-mount confocal microscopy for adult ear skin: a model system to study neuro-vascular branching morphogenesis and immune cell distribution

Here, we present a protocol of a whole-mount adult ear skin imaging technique to study comprehensive three-dimensional neuro-vascular branching morphogenesis and patterning, as well as immune cell distribution at a cellular level. The analysis of peripheral nerve and blood vessel anatomical structures in adult tissues provides some insights into the understanding of functional neuro-vascular wiring and neuro-vascular degeneration in pathological conditions such as wound healing. As a highly informative model system, we have focused our studies on adult ear skin, which is readily accessible for dissection. Our simple and reproducible protocol provides an accurate depiction of the cellular components in the entire skin, such as peripheral nerves (sensory axons, sympathetic axons, and Schwann cells), blood vessels (endothelial cells and vascular smooth muscle cells), and inflammatory cells. We believe this protocol will pave the way to investigate morphological abnormalities in peripheral nerves and blood vessels as well as the inflammation in the adult ear skin under different pathological conditions.

Adult mouse posterior ear skin (Figure 1A) and anterior ear skin (Figure 1B) were immunostained with antibodies to &#945;SMA (red), Tuj1 (green), and PECAM-1 (blue). Posterior skin was immunostained to study neuro-immune distribution using antibodies to CD11b (red) and MBP (green), together with Tuj1 (blue) (Figure 2A). Distribution of CD11b+ inflammatory cells, including macrophages was d...

Watch this Scientific Journal Video about Whole-mount Confocal Microscopy for Adult Ear Skin: A Model System to Study Neuro-vascular Branching Morphogenesis and Immune Cell Distribution at JoVE.com

Whole-mount Confocal Microscopy for Adult Ear Skin: A Model System to Study Neuro-vascular Branching Morphogenesis and Immune Cell Distribution

Here, we describe a high resolution whole-mount imaging method in the entire adult mouse ear skin, which enables us to visualize branching morphogenesis and patterning of peripheral nerves and blood vessels, as well as immune cell distribution.

Here, we present a protocol of a whole-mount adult ear skin imaging technique to study comprehensive three-dimensional neuro-vascular branching ...

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