We thank Dr. Mohamad Zubair for his helpful suggestions and technical assistance in the establishment of this protocol. This work was supported by National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health Research Grant 2R01-DK062027 (to G.D.H).

All methods were performed in accordance with institutionally approved protocols under the auspice of the University Committee on Use and Care of Animals at the University of Michigan.
1. Preparation for Surgery
<ol>
	<li>On the day prior to surgery, prepare 4% paraformaldehyde (PFA)/phosphate buffered saline (PBS). In case of frozen aliquots, proceed to thaw one and store at 4 &#176;C. 
	NOTE: 4% PFA is not stable for more than 48 h. 
	CAUTION: PFA is toxic, avoid contact with skin and eyes, and dispose in an appropriate container.</li>
	<li>On the day of the surgery, prepare the surgical instruments by sterilizing the scissors and forceps with 70% ethanol (EtOH) and let them dry on a paper towel.</li>
	<li>Place a 24-well plate filled with 1x PBS (1 mL/well is sufficient) in an ice bucket. 
	NOTE: Adrenals will be kept in this multi-well culture dish after surgery.</li>
</ol>
2. Adrenal Dissection
<ol>
	<li>Euthanize the mouse following standard protocols approved by the Institutional Animal Care and Use Committee (IACUC). A secondary method of euthanasia to ensure death (for example decapitation) is required.
	<ol>
		<li>For euthanasia by isoflurane overdose, place the mouse in a chamber filled with isoflurane vapors until respiration ceases, then remove the mouse from the chamber, lay it on a surface and perform cervical dislocation. 
		NOTE: Most euthanasia methods cause distress to the animal and are not suitable for stress studies because they may add the confounding variable of activation of the pituitary-adrenal axis and medullary catecholamine release. In this instance, decapitation is the suggested technique to adopt.</li>
	</ol>
	</li>
	<li>Lay the mouse supine, sterilize the incision area on the abdomen and flanks with 70% EtOH. 
	NOTE: While shaving the fur will increase sterility, for this particular application it is not necessary.</li>
	<li>Cut the skin in the middle of the abdomen using scissors, separate the skin from the peritoneum, deskin the mouse by pinching the skin around the cut and pulling it in two opposite directions (caudal and rostral). Then cut the peritoneum until reaching the posterior left and right flanks.</li>
	<li>Remove the murine adrenal gland cutting around the surrounding adipose tissue and place it in the 24-multiwell plate filled with 1x PBS and kept on ice.</li>
</ol>
3. Peri-adrenal Fat Removal
<ol>
	<li>Under a dissecting microscope, place the adrenal on a glass base or a Petri-dish on the stage plate, position the light source, select the magnification and adjust the focus to obtain a clear view of the entire adrenal. 
	NOTE: The magnification used can vary depending on personal preferences. A total magnification of 30X with a plan lens 1X, zoom 3X, and eyepiece 10X allows to visualize&#160;the whole gland with a good field of view.</li>
	<li>Quickly remove the adjacent fat tissues with two 25 G needles, avoiding dehydration of the adrenal. If this happens before all fat is removed, move the adrenal back into the well containing 1x PBS for 1&#8211;2 min, and then continue with the fat removal process.</li>
	<li>Wash 2x for 2 min each in 1x PBS.</li>
</ol>
4. Tissue Processing and Embedding
<ol>
	<li>Fix the tissues in 4% PFA/PBS at 4 &#176;C on a rocking platform for 2 h.</li>
	<li>Remove the 4% PFA and wash the tissues with 1x PBS, 3x for 15 min each at 4 &#176;C. 
	CAUTION: PFA is toxic and is a hazardous waste; it should be handled with caution under a chemical hood and disposed into a hazardous waste container.</li>
	<li>Incubate the adrenals in 50% EtOH at 4 &#176;C on a rocking platform for 2 h.</li>
	<li>Incubate the adrenals in 70% EtOH at 4 &#176;C on a rocking platform for a minimum of 2 h. 
	NOTE: If not proceeding with tissue processing for embedding, adrenals can be stored in 70% EtOH at 4 &#176;C. Avoiding long-term storage in 70% EtOH and proceeding to tissue processing as soon as possible yields better quality samples.</li>
	<li>Prepare the adrenal for tissue processing by wrapping it in gauze and enclosing it in a tissue embedding cassette. Place the cassette in a jar filled with 70% EtOH and store at 4 &#176;C until ready to move to the tissue processor. Insert the cassette into the tissue processor programmed as reported in Table 1 and run the program.</li>
	<li>Transfer the cassette into an embedding station filled with melted paraffin at 65 &#176;C. If a cooling station is not available, position a cold cooling tray next to it.</li>
	<li>Label an embedding mold and open the tissue embedding cassette. Using a pair of forceps, unwrap the gauze and place the adrenal gently in the desired position at the center of the base in the embedding mold. Pour the melted paraffin on the adrenal. If necessary, hold the adrenal with forceps to secure its position in the mold otherwise it may move around inside the mold.</li>
	<li>Gently move the embedding mold to the cooling tray and wait until the hardening of the paraffin. After that, to facilitate sectioning, store embedding molds in a cool place.</li>
</ol>
5. Sectioning with a Rotary Microtome
<ol>
	<li>Check that the microtome is clean before starting, brush away all discarded paraffin residues, ensure that the knife (or blade) is sharpened, oil the internal mechanism and fully retract the block holder if necessary.</li>
	<li>Label a series of microscope slides (positively charged or coated to prevent tissue loss (see Table of Materials)), lay them on a slide warmer set at 37 &#176;C, and dispense some autoclaved type 1 ultrapure water on top of each slide.</li>
	<li>Set section thickness at 5 &#181;m.</li>
	<li>Insert the microtome blade in the blade holder, control the angle of the blade, make sure that the blade is firmly secured into the holder and check the clearance of the paraffin block and block holder.</li>
	<li>Bring the block holder to its highest position and, if possible, lock the operating handle, remove the paraffin block from the mold and place it into the block holder securing it firmly with the clamp. The angle of the center line of the blade with the facing surface of the block should be about 20&#176;. If necessary, readjust the paraffin block. 
	CAUTION: The blade is sharp.</li>
	<li>If previously locked, unlock the hand wheel and lower the paraffin block until its face is level with the edge of the microtome blade. Rotate the hand wheel with a steady rhythm. Perform initial trimming to remove the paraffin and to expose the adrenal.</li>
	<li>Keep turning the hand wheel, and section until&#160;the end of the adrenal. Use a brightfield or dissecting microscope to check for the presence of tissue in the sections. Detach the ribbon from the blade and with the help of another pair of forceps place it on the water laid on the glass slide. It may be useful to place the ribbon on a surface, stretch it carefully, and then mount it on the slide.</li>
	<li>Let the slides dry on the hot plate. Then lay them flat on a slide tray and bake at 37 &#176;C overnight or longer if water is still present. Once dry, store the slides in a slide box at room temperature.</li>
	<li>Put away all the used equipment and clean the microtome.</li>
</ol>
6. Immunofluorescence
<ol>
	<li>Select the slides for immunostaining and place them in a slide holder.</li>
	<li>On a hot plate, bring a beaker filled with 0.01M citrate at pH 2.0 to boil. The volume of the buffer depends on the beaker size and must be enough for covering the sections on the slides during boiling (some evaporation needs to be taken into account). Cover the beaker with aluminum foil. 
	NOTE: Other methods for antigen retrieval are available (see Discussion).</li>
	<li>Deparaffinize the slides in 100% xylene 2x for 5 min each. Rehydrate the slides using the following series: 100% EtOH 2x for 5 min, 70% EtOH 2x for 5 min, type 1 ultrapure water for 5 min. 
	NOTE: After deparaffinization, it is important to not let the sections dry out: tissue sections must always be covered with buffers or solutions until the end of the procedure or the tissue structure can be damaged.</li>
	<li>For antigen retrieval, place slides in a metal slide holder and insert it in the beaker with boiling citrate without the aluminum foil. Let it boil for 10 min.</li>
	<li>Remove the beaker from the hot plate and let it cool for 20 min. Make sure that the adrenal sections are still covered with the buffer.</li>
	<li>Prepare the blocking solution. If using the commercially available staining kit employed for the Representative Results (see the Table of Materials), in a tube add 1.25 mL of 1x PBS, 1 drop (equal to about 45 &#181;L) of Mouse Ig Blocking Reagent, and 5% of normal goat serum. Store the blocking solution at 4 &#176;C or on ice while working. 
	NOTE: The serum used depends on the secondary antibody&#39;s host species. Here secondary antibodies raised in goat have been used. For other antibodies, different serum concentrations may be necessary. Empirically determine the correct serum concentration by testing several concentrations.</li>
	<li>Transfer the slides into a Coplin jar containing 1x PBS and wash 3x 10 min each on a rocker with gentle rocking.</li>
	<li>Prepare a humidified chamber for the staining.</li>
	<li>Gently, shake off the PBS from one slide; wipe the slide bottom with a lint-free wipe to remove the excess PBS.</li>
	<li>Using a special marker for slides with hydrophobic properties, draw a circle surrounding each adrenal section, making sure that the glass surface is dry to avoid spreading of the ink solution to the section. If necessary, carefully wipe dry the surface. Place the slide in the humidified chamber.</li>
	<li>Quickly, pipette 50 &#181;L (or enough to cover sections) of blocking solution onto every section. Incubate for 1 h at room temperature. 
	NOTE: Blocking solution volume needed may vary; it is important that the sections are well covered with the solution.</li>
	<li>Prepare the diluent solution from the commercially available kit with 7.5 mL of 1x PBS, 600 &#181;L of protein concentrate stock solution and 5% normal goat serum (or any other serum and concentration used in the blocking solution). Store the diluent solution at 4 &#176;C or on ice while working.</li>
	<li>Prepare the primary antibody solutions diluting the primary antibodies at the appropriate concentrations in the diluent solution. For co-staining, add an aliquot of each antibody in a new tube, and mix gently. Place antibodies and antibody solutions on ice until ready to use. 
	NOTE: Here we employed anti-SF1 antibody raised in rabbit and an anti-TH antibody raised in mouse. To prepare the antibody working solutions follow as directed.
	<ol>
		<li>For SF1 working solution, in one tube, add 1 &#181;L of anti-SF1 antibody to 999 &#181;L of diluent solution (final concentration of 1.5 &#181;g/mL). For TH working solution, in a tube, add 1 &#181;L anti-TH antibody in 499 &#181;L of diluent solution (estimated final concentration of 2 - 6 &#181;g/mL).</li>
		<li>For SF1 + TH antibody working mix, in a fresh tube, pipette 250 &#181;L of SF1 working solution and 250 &#181;L of TH working solution. Mix gently by pipetting. Store on ice.</li>
	</ol>
	</li>
	<li>Transfer the slides in a Coplin jar containing 1x PBS and wash 3x for 5 min each on a rocker with gentle rocking.</li>
	<li>Place the slides back into the humidified chamber after wiping off excess of PBS, pipette the SF1 + TH antibody working mix (or other primary antibody solution) on each section, close the humidified chamber and leave it overnight at 4 &#176;C.</li>
	<li>On the following day, move the slides into a Coplin jar containing 1x PBS and wash 3x for 15 min on a rocker with gentle rocking.</li>
	<li>While washing the slides, prepare the secondary antibody solution in the diluent solution using the appropriate concentration. If performing co-staining, add equal amount of each secondary antibody solution in a new tube. Mix gently by pipetting. Store on ice. Protect the tubes from light and store on ice until ready to use. 
	NOTE: Here, the secondary antibodies used are 488 nm fluorescent dye-labeled anti-mouse raised in goat and 549 fluorescent dye-labeled anti-rabbit raised in goat. The secondary antibody solution was prepared by adding 0.5 &#181;L of each secondary antibody in 799 &#181;L of diluent solution (final concentrations of 1.2 &#181;g/mL).</li>
	<li>Place the slides back in the humidified chamber after removing excess of PBS, quickly pipette the secondary antibody solution on the adrenal sections, close the humidified chamber and protect from light. Incubate for 1 h at room temperature.</li>
	<li>Wash the slides in a Coplin jar with 1x PBS and wash 3x for 15 min on a rocker with gentle rocking, making sure to protect them from light.</li>
	<li>Prepare the 4&#39;,6-diamidino-2-phenylindole (DAPI) solution for nuclear staining: 1 &#181;L of DAPI (20 mg/mL) in 1 mL of 1x PBS. 
	NOTE: Blue-fluorescent nuclear counterstain can also be achieved using Hoechst dye.</li>
	<li>Pipette DAPI solution onto the adrenal sections, cover from light and incubate at room temperature for 7 min.</li>
	<li>Wash the slides in a Coplin jar with 1x PBS and wash 3x for 5 min on a rocker with gentle rocking while protecting the slides from light.</li>
	<li>In an area shielded from direct light, lay down a cover glass, and pipette 60 &#181;L or about 3 drops of mounting agent suitable for immunofluorescence along the surface of the cover glass.</li>
	<li>Gently wipe the back of a slide with a lint-free wipe, position the slide face down toward the cover glass and parallel to it, so the tissue sections face the cover glass with the mounting agent on it. Lightly press the slide on the cover glass and make sure that no air bubble is trapped between the slide and the cover glass.
	<ol>
		<li>If necessary, apply further pressure to remove the air bubbles and the excess of mounting agent.</li>
	</ol>
	</li>
	<li>Lay down the slide in a dark container and cure at room temperature for a minimum of 24 h (or the time indicated in the information sheet of the mounting agent used) and then proceed to imaging.</li>
</ol>
7. Imaging
NOTE: A fluorescence microscope connected to a camera is required for detecting and capturing the fluorescence emitted by the tissues after excitation at determined wavelengths. While obvious, it is important to remember to choose the secondary antibody conjugated with fluorochromes whose excitation and emission spectra are compatible with the equipment available. Imaging settings vary according to the microscope and the software used for capturing images. There are some basic rules that apply for imaging adrenal sections, such as making sure that the exposure time, camera gain settings, and light source intensity are kept constant.
<ol>
	<li>Turn on the light source and the camera, launch the imaging software following the manufacturer&#39;s directions. 
	NOTE: The order of these actions can differ depending on the equipment used.</li>
	<li>Secure the slide on the stage, open the shutter, and looking into the microscope eyepieces use nuclear staining (DAPI) channel and low magnification (4X) to identify the tissue on the slide: adrenal sections are small, and their visualization may require some time.</li>
	<li>Change to a higher magnification (10X), focus, and close the shutter. 
	NOTE: It is important to avoid unnecessarily long exposition under the light that can cause photobleaching, resulting in loss of signal.</li>
	<li>Using the software commands, select the objective (10X) and the channel in use (DAPI), adjust exposure time (1 s, can be adjusted if the signal is too strong or weak). If available, set binning for live imaging (not acquisition) to &#39;2 X 2&#39;, conversion gain to &#39;mid&#39;, readout speed to &#39;20 MHz&#39;. If the software used does not display the scale bar at the end of the imaging, select the scale bar option from the menu and position the bar where desired.</li>
	<li>Open the shutter, re-adjust the focus if necessary, and switch channels (FITC, TRITC, DAPI). If the microscope is not automated, take a picture of the adrenal in each channel without moving the stage and make sure to adjust the selection of the channel in use. Close the shutter once finished. 
	NOTE: Write down the settings employed in case the software does not automatically save them.</li>
	<li>Save the pictures. 
	NOTE: Merged pictures can be often created using the microscope&#39;s software or other graphics editor software packages.</li>
	<li>Repeat imaging for other areas of the section and/or with a higher magnification. 
	NOTE: A 20X magnification often requires a shorter exposure time (i.e., 800 ms).</li>
	<li>At the end of imaging, shut off all the equipment in the proper order.</li>
</ol>

<ol>
	<li>Brandtzaeg, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+increasing+power+of+immunohistochemistry+and+immunocytochemistry.">The increasing power of immunohistochemistry and immunocytochemistry.</a> Journal of Immunological Methods. 216 (1-2), 49-67 (1998).</li><li>Matos, L. L., Trufelli, D. C., de Matos, M. G., da Silva Pinhal, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunohistochemistry+as+an+important+tool+in+biomarkers+detection+and+clinical+practice.">Immunohistochemistry as an important tool in biomarkers detection and clinical practice.</a> Biomark Insights. 5, 9-20 (2010).</li><li>Coons, A. H., Creech, H. J., Jones, R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunological+properties+of+an+antibody+containing+a+fluorescent+group.">Immunological properties of an antibody containing a fluorescent group.</a> Proceedings of the Society for Experimental Biology and Medicine. 47 (2), 200-202 (1941).</li><li>Lerario, A. M., Finco, I., LaPensee, C., Hammer, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+Mechanisms+of+Stem/+Progenitor+Cell+Maintenance+in+the+Adrenal+Cortex.">Molecular Mechanisms of Stem/ Progenitor Cell Maintenance in the Adrenal Cortex.</a> Frontiers in Endocrinology. 8, (2017).</li><li>Yates, R., 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=Adrenocortical+Development,+Maintenance,+and+Disease.">Adrenocortical Development, Maintenance, and Disease.</a> Endocrine Gland Development and Disease. 106, 239-312 (2013).</li><li>Jones, I. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Variation+in+the+Mouse+Adrenal+Cortex+with+Special+Reference+to+the+Zona+Reticularis+and+to+Brown+Degeneration,+Together+with+a+Discussion+of+the+Cell+Migration+Theory.">Variation in the Mouse Adrenal Cortex with Special Reference to the Zona Reticularis and to Brown Degeneration, Together with a Discussion of the Cell Migration Theory.</a> Quarterly Journal of Microscopical Science. 89 (1), 53 (1948).</li><li>Sucheston, M. E. C., Samuel, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Transient-Zone+in+the+Human+and+Mouse+Adrenal+Gland.">The Transient-Zone in the Human and Mouse Adrenal Gland.</a> The Ohio Journal of Science. 72, 120-126 (1972).</li><li>Guasti, L., Paul, A., Laufer, E., King, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localization+of+Sonic+hedgehog+secreting+and+receiving+cells+in+the+developing+and+adult+rat+adrenal+cortex.">Localization of Sonic hedgehog secreting and receiving cells in the developing and adult rat adrenal cortex.</a> Molecular and Cellular Endocrinology. 336 (1-2), 117-122 (2011).</li><li>Pihlajoki, M., Dorner, J., Cochran, R. S., Heikinheimo, M., Wilson, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adrenocortical+zonation,+renewal,+and+remodeling.">Adrenocortical zonation, renewal, and remodeling.</a> Frontiers in Endocrinology. 6, 27 (2015).</li><li>Farese, R. V., Walther, T. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+Droplets+Finally+Get+a+Little+R-E-S-P-E-C-T.">Lipid Droplets Finally Get a Little R-E-S-P-E-C-T.</a> Cell. 139 (5), 855-860 (2009).</li><li>Shen, W. J., Azhar, S., Kraemer, F. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+droplets+and+steroidogenic+cells.">Lipid droplets and steroidogenic cells.</a> Experimental Cell Research. 340 (2), 209-214 (2016).</li><li>Finco, I., LaPensee, C. R., Krill, K. T., Hammer, G. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hedgehog+signaling+and+steroidogenesis.">Hedgehog signaling and steroidogenesis.</a> Annual Review of Physiology. 77, 105-129 (2015).</li><li>Paul, A., Laufer, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endogenous+biotin+as+a+marker+of+adrenocortical+cells+with+steroidogenic+potential.">Endogenous biotin as a marker of adrenocortical cells with steroidogenic potential.</a> Molecular and Cellular Endocrinology. 336 (1-2), 133-140 (2011).</li><li>Lowe, J., Anderson, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Stevens &amp; Lowe's Human Histology, 4th Edition. , 263-285 (2015).</li><li>Nagatsu, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genes+for+human+catecholamine-synthesizing+enzymes.">Genes for human catecholamine-synthesizing enzymes.</a> Neuroscience Research. 12 (2), 315-345 (1991).</li><li>Berthon, 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=Age-dependent+effects+of+Armc5+haploinsufficiency+on+adrenocortical+function.">Age-dependent effects of Armc5 haploinsufficiency on adrenocortical function.</a> Human Molecular Geneticst. 26 (18), 3495-3507 (2017).</li><li>Brown, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antigen+retrieval+methods+for+immunohistochemistry.">Antigen retrieval methods for immunohistochemistry.</a> Toxicologic Pathology. 26 (6), 830-831 (1998).</li><li>Billinton, N., Knight, A. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Seeing+the+wood+through+the+trees:+a+review+of+techniques+for+distinguishing+green+fluorescent+protein+from+endogenous+autofluorescence.">Seeing the wood through the trees: a review of techniques for distinguishing green fluorescent protein from endogenous autofluorescence.</a> Analytical Biochemistry. 291 (2), 175-197 (2001).</li><li>Hirsch, R. E., San George, R. C., Nagel, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intrinsic+fluorometric+determination+of+the+stable+state+of+aggregation+in+hemoglobins.">Intrinsic fluorometric determination of the stable state of aggregation in hemoglobins.</a> Analytical Biochemistry. 149 (2), 415-420 (1985).</li><li>Whittington, N. C., Wray, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Suppression+of+Red+Blood+Cell+Autofluorescence+for+Immunocytochemistry+on+Fixed+Embryonic+Mouse+Tissue.">Suppression of Red Blood Cell Autofluorescence for Immunocytochemistry on Fixed Embryonic Mouse Tissue.</a> Current Protocols in Neuroscience. 81, 28 (2017).</li><li>Watson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Suppressing+autofluorescence+of+erythrocytes.">Suppressing autofluorescence of erythrocytes.</a> Biotechnic &amp; Histochemistry. 86 (3), 207 (2011).</li><li>Epp, J. R., 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=Optimization+of+CLARITY+for+Clearing+Whole-Brain+and+Other+Intact+Organs.">Optimization of CLARITY for Clearing Whole-Brain and Other Intact Organs.</a> eNeuro. 2 (3), (2015).</li><li>Erturk, 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=Three-dimensional+imaging+of+solvent-cleared+organs+using+3DISCO.">Three-dimensional imaging of solvent-cleared organs using 3DISCO.</a> Nature Protocols. 7 (11), 1983-1995 (2012).</li></ol>

The authors have nothing to disclose.

This protocol describes a method for the isolation of mouse adrenal glands together with the preparation and staining of sectioned paraffin-embedded mouse adrenals.
Compared to other protocols we tested, this immunofluorescence protocol has proven suitable for the majority of antibodies used in our laboratory. However, in certain cases it may require some adjustments to improve the staining results. One variable that can easily be modified and tested is the length of fixation. In our laborator...

Immunohistochemistry is a technique for detecting tissue components with the use of antibodies to specific cellular molecules and subsequent staining techniques to detect the conjugated antibodies1. This immunohistochemical procedure requires specific fixation and processing of tissues that are often empirically determined for the specific antigen, tissue and antibody utilized2. Fixation is crucial to preserve the &#34;original&#34; state of the tissue and thereby maintaining intact cellular and subcellular structures and expression patterns. Further processing and embedding procedures are required to prepare the tissue for sectioning into thin slices that are used for histologic studies involving immunohistochemistry.
Immunostaining can be performed with either chromogenic or fluorescent detection. Chromogenic detection requires the utilization of an enzyme to convert a soluble substrate into an insoluble colored product. While this enzyme can be conjugated to the antibody recognizing the antigen (primary antibody), it is more often conjugated to the antibody recognizing the primary antibody (i.e., the secondary antibody). This technique is highly sensitive; the colored product resulting from the enzymatic reaction is photostable and requires only a brightfield microscope for imaging. However, chromogenic immunostaining may not be suitable when trying to visualize two proteins that co-localize, since the deposition of one color can mask the deposition of the other one. In the case of co-staining, immunofluorescence has proven to be more advantageous. The advent of immunofluorescence is attributed to Albert Coons and colleagues, who developed a system to identify tissue antigens with antibodies marked with fluorescein and visualize them in the sectioned tissues under ultraviolet light3. Fluorescence detection is based on an antibody conjugated with a fluorophore that emits light after excitation. Because there are several fluorophores with emissions at different wavelengths (with no or little overlap), this detection method is ideal for the studies of multiple proteins.
The adrenal gland is a paired organ located above the kidney and characterized by two embryologically distinct components surrounded by a mesenchymal capsule. The outer adrenal cortex, derived from the mesonephric intermediate mesoderm, secretes steroid hormones while the inner medulla, derived from the neural crest, produces catecholamines including adrenaline, noradrenaline, and dopamine. The adrenal cortex is histologically and functionally divided in three concentric zones, with each zone secreting different classes of steroid hormones: the outer zona glomerulosa (zG) produces mineralocorticoids that regulate electrolyte homeostasis and intravascular volume; the middle zona fasciculata (zF), directly beneath the zG, secretes glucocorticoids that mediate the stress response through the mobilization of energy stores to increase plasma glucose; and the inner zona reticularis (zR), which synthesizes sex steroid precursors (i.e., dehydroepiandrosterone (DHEAS))4.
Some variation in adrenocortical zonation is present between species: for example, Mus musculus lacks the zR. The unique postnatal X-zone of M. musculus is a remnant of the fetal cortex characterized by small lipid-poor cells with acidophilic cytoplasms5. The X-zone disappears at puberty in male mice and after the first pregnancy in female mice, or gradually degenerates in not-bred females6,7. Moreover, the tortuosity and thickness of the zG exhibits marked variation between species as does organization of peripheral stem and progenitor cells in and adjacent to the zG. The rat, unlike other rodents, has a visible undifferentiated zone (zU) between the zG and zF that functions as a stem cell zone and/or a zone of transient amplifying progenitors. Whether the zU is unique to rats or simply a more prominently organized cluster of cells is unknown8,9.
Cells of the adrenal cortex contain lipid droplets that store cholesterol esters that serve as the precursor of all steroid hormones10,11.&#160; The term &#34;steroidogenesis&#34; defines the process of production of steroid hormones from cholesterol via a series of enzymatic reactions that involve the activity of steroidogenic factor 1 (SF1), whose expression is a marker of steroidogenic potential. In the adrenal gland, Sf1 expression is present only in cells of the cortex12. An interesting study found the expression of endogenous biotin in adrenocortical cells with steroidogenic potential13. While this can be the cause of a higher background in biotin/streptavidin-based staining methods, due to the detection of endogenous biotin by antibody conjugated with streptavidin, this characteristic could be also employed to distinguish the steroidogenic cells from other populations within the adrenal gland, i.e., endothelial, capsular, and medulla cells.
Innervated by sympathetic preganglionic neurons, the adrenal medulla is characterized by basophilic cells with a granular cytoplasm containing epinephrine and norepinephrine. Medulla cells are named &#34;chromaffin&#34; due to the high content of catecholamines that form a brown pigment after oxidation14. Tyrosine hydroxylase (TH) is the enzyme that catalyzes the rate-limiting step in the synthesis of catecholamines and, in the adrenal gland, is expressed only in the medulla15.
Here we present a protocol for the isolation of mouse adrenal glands, their processing for embedding in paraffin and sectioning, and a method to perform immunofluorescence staining on adrenal sections in order to identify the cellular types constituting the adrenal cortex and medulla. This protocol is a standard in our laboratory for immunostaining with multiple antibodies routinely used in our research.

<table border="0" cellpadding="0" cellspacing="0" style="width:657px;" width="658">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">24-well cell culture plate</td>
			<td style="width:156px;">Nest Biotechnology Co.</td>
			<td style="width:119px;">0412B</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Disposable needles 25Gx5/8&#34;</td>
			<td style="width:156px;">Exel International</td>
			<td style="width:119px;">26403</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Paraformaldehyde (PFA)</td>
			<td>Sigma-Aldrich&#160;</td>
			<td>P6148</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Paraplast plus&#160;</td>
			<td style="width:156px;">McCormik scientific</td>
			<td style="width:119px;">39502004</td>
			<td>Paraffin for tissue embedding</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Shandon biopsy cassettes II with attached lid</td>
			<td style="width:156px;">Thermo scientific</td>
			<td style="width:119px;">1001097</td>
			<td>Cassettes for tissue processing</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">High Profile Microtome Blades</td>
			<td style="width:156px;">Accu-Edge</td>
			<td style="width:119px;">4685</td>
			<td>Disposable stainless steel blades</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Peel-a-way disposable plastic tissue embedding molds</td>
			<td style="width:156px;">Polysciences Inc.</td>
			<td style="width:119px;">18986</td>
			<td>Truncated,22mm square top tapered to 12mm bottom</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Superfrost Plus Microscope Slides</td>
			<td style="width:156px;">Fisherbrand</td>
			<td style="width:119px;">12-550-15</td>
			<td>75x25x1 mm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Xylene</td>
			<td style="width:156px;">Fisher Chemical</td>
			<td style="width:119px;">X5P1GAL&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">200 Proof Ethanol</td>
			<td style="width:156px;">Decon Labs, Inc.</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Certi-Pad Gauze pads&#160;</td>
			<td style="width:156px;">Certified Safety Mfg, Inc</td>
			<td style="width:119px;">231-210</td>
			<td>3&#34;x3. Sterile latex free gauze pads</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">M.O.M kit&#160;</td>
			<td style="width:156px;">Vector laboratories</td>
			<td style="width:119px;">BMK-2202</td>
			<td>For detecting mouse primary antibodies on mouse tissue</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">KimWipes</td>
			<td style="width:156px;">Kimtech</td>
			<td style="width:119px;">34155</td>
			<td>Wipes 4.4x8.4 inch</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Super PAP PEN</td>
			<td style="width:156px;">Invitrogen&#160;</td>
			<td style="width:119px;">00-8899</td>
			<td>Pen to draw on slides</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Microscope cover glass&#160;</td>
			<td style="width:156px;">Fisherbrand</td>
			<td style="width:119px;">12-544-D</td>
			<td>Size: 22x50x1.5</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">DAPI</td>
			<td style="width:156px;">Sigma</td>
			<td style="width:119px;">D9542&#160;</td>
			<td>(Prepared in 20mg/mL stock)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">ProLong Gold antifade reagent</td>
			<td style="width:156px;">Molecular Probes</td>
			<td style="width:119px;">P36930</td>
			<td>Mounting agent for immunofluorescence</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">X-cite series 120Q</td>
			<td style="width:156px;">Lumen Dynamics</td>
			<td style="width:119px;"></td>
			<td style="width:167px;">Light source</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Coolsnap Myo</td>
			<td style="width:156px;">Photometrics</td>
			<td style="width:119px;"></td>
			<td>Camera</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Optiphot-2&#160;</td>
			<td style="width:156px;">Nikon</td>
			<td style="width:119px;"></td>
			<td>Microscope</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">microtome</td>
			<td style="width:156px;">Americal Optical</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tissue embedder</td>
			<td style="width:156px;">Leica</td>
			<td style="width:119px;">EG1150 H&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tissue processor&#160;</td>
			<td style="width:156px;">Leica</td>
			<td style="width:119px;">ASP300S</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Normal goat serum</td>
			<td style="width:156px;">Sigma</td>
			<td style="width:119px;">G9023</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Mouse anti-TH</td>
			<td style="width:156px;">Millipore</td>
			<td style="width:119px;">MAB318</td>
			<td>Primary antibody</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Rabbit anti-SF1</td>
			<td>Ab proteintech group (PTGlabs)</td>
			<td style="width:119px;">&#160;custom made</td>
			<td>Primary antibody</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Alexa-488 Mouse IgG&#160; raised goat</td>
			<td style="width:156px;">Jackson ImmunoResearch</td>
			<td>115-545-003&#160;</td>
			<td>Secondary antibody</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Dylight-549 Rabbit IgG raised goat</td>
			<td style="width:156px;">Jackson ImmunoResearch</td>
			<td>111-505-003</td>
			<td>Secondary antibody</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Citrate acid anhydrous</td>
			<td style="width:156px;">Fisher Chemical</td>
			<td style="width:119px;">A940-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">NIS-Elements Basic Research&#160;</td>
			<td style="width:156px;">Nikon</td>
			<td style="width:119px;"></td>
			<td>Software for imaging</td>
		</tr>
	</tbody>
</table>

isolation, fixation, and immunofluorescence imaging of mouse adrenal glands

Immunofluorescence is a well-established technique for detection of antigens in tissues with the employment of fluorochrome-conjugated antibodies and has a broad spectrum of applications. Detection of antigens allows for characterization and identification of multiple cell types. Located above the kidneys and encapsulated by a layer of mesenchymal cells, the adrenal gland is an endocrine organ composed by two different tissues with different embryological origins, the mesonephric intermediate mesoderm-derived outer cortex and the neural crest-derived inner medulla. The adrenal cortex secretes steroids (i.e., mineralocorticoids, glucocorticoids, sex hormones), whereas the adrenal medulla produces catecholamines (i.e., adrenaline, noradrenaline). While conducting adrenal research, it is important to be able to distinguish unique cells with different functions. Here we provide a protocol developed in our laboratory that describes a series of sequential steps required for obtaining immunofluorescence staining to characterize the cell types of the adrenal gland. We focus first on the dissection of the mouse adrenal glands, the microscopic removal of periadrenal fat followed by the fixation, processing and paraffin embedding of the tissue. We then describe sectioning of the tissue blocks with a rotary microtome. Lastly, we detail a protocol for immunofluorescent staining of adrenal glands that we have developed to minimize both non-specific antibody binding and autofluorescence in order to achieve an optimal signal.

Figure 1&#160;represents a schematic of the entire protocol described above. Adrenal glands are harvested from mice, adjacent adipose tissue is removed under a dissecting microscope, and the adrenal are then fixed in 4% PFA. After this step, adrenals are processed and embedded in paraffin, and sectioned with a microtome to cut the organ into thin slices that are deposited on microscope slides. After drying of the sections, immunofluorescence is carried out an...

Watch this Scientific Journal Video about Isolation, Fixation, and Immunofluorescence Imaging of Mouse Adrenal Glands at JoVE.com

Isolation, Fixation, and Immunofluorescence Imaging of Mouse Adrenal Glands

Here we present a method to isolate adrenal glands from mice, fix the tissues, section them, and perform immunofluorescence staining.

Immunofluorescence is a well-established technique for detection of antigens in tissues with the employment of fluorochrome-conjugated antibodies and has ...

isolation-fixation-immunofluorescence-imaging-mouse-adrenal

Research

Education

JoVE Core

JoVE Journal

Anatomy and Physiology

Immunology and Infection

Unit 1

The Endocrine System

SCIENTISTS IN ACTION

23.4K Views.  University of Michigan Health System. Here we present a method to isolate adrenal glands from mice, fix the tissues, section them, and perform immunofluorescence staining.

Video: Isolation, Fixation, and Immunofluorescence Imaging of Mouse Adrenal Glands

Isolation of Mouse Peritoneal Cavity Cells

The peritoneal cavity is a membrane-bound and fluid-filled abdominal cavity of mammals, which contains the liver, spleen, most of the gastro-intestinal tract and other viscera. It harbors a number of immune cells including macrophages, B cells and T cells. The presence of a high number of na&iuml;ve macrophages in the peritoneal cavity makes it a preferred site for the collection of na&iuml;ve tissue resident macrophages (1). The peritoneal cavity is also important to the study of B cells because of the presence of a unique peritoneal cavity-resident B cell subset known as B1 cells in addition to conventional B2 cells. B1 cells are subdivided into B1a and B1b cells, which can be distinguished by the surface expression of CD11b and CD5. B1 cells are an important source of natural IgM providing early protection from a variety of pathogens (2-4). These cells are autoreactive in nature (5), but how they are controlled to prevent autoimmunity is still not understood completely. On the contrary, CD5+ B1a cells possess some regulatory properties by virtue of their IL-10 producing capacity (6). Therefore, peritoneal cavity B1 cells are an interesting cell population to study because of their diverse function and many unaddressed questions associated with their development and regulation. The isolation of peritoneal cavity resident immune cells is tricky because of the lack of a defined structure inside the peritoneal cavity. Our protocol will describe a procedure for obtaining viable immune cells from the peritoneal cavity of mice, which then can be used for phenotypic analysis by flow cytometry and for different biochemical and immunological assays.

The peritoneal cavity in mammals contains different immune cell populations crucial for innate immune responses. An efficient isolation method is required for biochemical and functional analyses of these cells. Here we provide a comprehensive method for the isolation of peritoneal cavity cells in the mouse.

The peritoneal cavity is a membrane-bound and fluid-filled abdominal cavity of mammals, which contains the liver, spleen, most of the gastro-intestinal ...

Intravital Imaging of the Mouse Thymus using 2-Photon Microscopy

Two-photon Microscopy (TPM) provides image acquisition in deep areas inside tissues and organs. In combination with the development of new stereotactic tools and surgical procedures, TPM becomes a powerful technique to identify "niches" inside organs and to document cellular "behaviors" in live animals. While intravital imaging provides information that best resembles the real cellular behavior inside the organ, it is both more laborious and technically demanding in terms of required equipment/procedures than alternative ex vivo imaging acquisition. Thus, we describe a surgical procedure and novel "stereotactic" organ holder that allows us to follow the movements of Foxp3+ cells within the thymus.
Foxp3 is the master regulator for the generation of regulatory T cells (Tregs). Moreover, these cells can be classified according to their origin: ie. thymus-differentiated Tregs are called "naturally-occurring Tregs" (nTregs), as opposed to peripherally-converted Tregs (pTregs). Although significant amount of research has been reported in the literature concerning the phenotype and physiology of these T cells, very little is known about their in vivo interactions with other cells. This deficiency may be due to the absence of techniques that would permit such observations. The protocol described in this paper provides a remedy for this situation.
Our protocol consists of using nude mice that lack an endogenous thymus since they have a punctual mutation in the DNA sequence that compromises the differentiation of some epithelial cells, including thymic epithelial cells. Nude mice were gamma-irradiated and reconstituted with bone marrows (BM) from Foxp3-KIgfp/gfp mice. After BM recovery (6 weeks), each animal received embryonic thymus transplantation inside the kidney capsule. After thymus acceptance (6 weeks), the animals were anesthetized; the kidney containing the transplanted thymus was exposed, fixed in our organ holder, and kept under physiological conditions for in vivo imaging by TPM. We have been using this approach to study the influence of drugs in the generation of regulatory T cells.

We have developed novel laboratory tools and protocols for intravital imaging acquisition of the thymus. Our technique should help in the identification of &#x201C;niches&#x201D; within the thymus where T cell development occurs.

Two-photon Microscopy (TPM) provides image acquisition in deep areas inside tissues and organs. In combination with the development of new stereotactic ...

Isolation of Mouse Lung Dendritic Cells

Lung dendritic cells (DC) play a fundamental role in sensing invading pathogens 1,2 as well as in the control of tolerogenic responses 3 in the respiratory tract. At least three main subsets of lung dendritic cells have been described in mice: conventional DC (cDC) 4, plasmacytoid DC (pDC) 5 and the IFN-producing killer DC (IKDC) 6,7. The cDC subset is the most prominent DC subset in the lung 8. 
The common marker known to identify DC subsets is CD11c, a type I transmembrane integrin (&beta;2) that is also expressed on monocytes, macrophages, neutrophils and some B cells 9. In some tissues, using CD11c as a marker to identify mouse DC is valid, as in spleen, where most CD11c+ cells represent the cDC subset which expresses high levels of the major histocompatibility complex class II (MHC-II). However, the lung is a more heterogeneous tissue where beside DC subsets, there is a high percentage of a distinct cell population that expresses high levels of CD11c bout low levels of MHC-II. Based on its characterization and mostly on its expression of F4&#47;80, an splenic macrophage marker, the CD11chiMHC-IIlo lung cell population has been identified as pulmonary macrophages 10 and more recently, as a potential DC precursor 11. 
In contrast to mouse pDC, the study of the specific role of cDC in the pulmonary immune response has been limited due to the lack of a specific marker that could help in the isolation of these cells. Therefore, in this work, we describe a procedure to isolate highly purified mouse lung cDC. The isolation of pulmonary DC subsets represents a very useful tool to gain insights into the function of these cells in response to respiratory pathogens as well as environmental factors that can trigger the host immune response in the lung.

A highly purified preparation of mouse lung dendritic cells is described. Specific emphasis is given to the isolation of conventional dendritic cell subset.

Lung dendritic cells (DC) play a fundamental role in sensing invading pathogens 1,2 as well as in the control of tolerogenic responses 3 in the ...

Hybridization in situ of Salivary Glands, Ovaries, and Embryos of Vector Mosquitoes

Mosquitoes are vectors for a diverse set of pathogens including arboviruses, protozoan parasites and nematodes. Investigation of transcripts and gene regulators that are expressed in tissues in which the mosquito host and pathogen interact, and in organs involved in reproduction are of great interest for strategies to reduce mosquito-borne disease transmission and disrupt egg development. A number of tools have been employed to study and validate the temporal and tissue-specific regulation of gene expression. Here, we describe protocols that have been developed to obtain spatial information, which enhances our understanding of where specific genes are expressed and their products accumulate. The protocol described has been used to validate expression and determine accumulation patterns of transcripts in tissues related to mosquito-borne pathogen transmission, such as female salivary glands, as well as subcellular compartments of ovaries and embryos, which relate to mosquito reproduction and development. 
 The following procedures represent an optimized methodology that improves the efficiency of various steps in the protocol without loss of target-specific hybridization signals. Guidelines for RNA probe preparation, dissection of soft tissues and the general procedure for fixation and hybridization are described in Part A, while steps specific for the collection, fixation, pre-hybridization and hybridization of mosquito embryos are detailed in Part B.

Hybridization in situ of Salivary Glands, Ovaries, and Embryos of Vector Mosquitoes

Temporal and spatial gene expression analyses have a crucial role in functional genomics. Whole-mount hybridization in situ is useful for determining the localization of transcripts within tissues and subcellular compartments. Here we outline a hybridization in situ protocol with modifications for specific target tissues in mosquitoes.

Mosquitoes are vectors for a diverse set of pathogens including arboviruses, protozoan parasites and nematodes.  Investigation of transcripts and gene ...

Intravital Imaging of the Mouse Popliteal Lymph Node

Lymph nodes (LNs) are secondary lymphoid organs, which are strategically located throughout the body to allow for trapping and presentation of foreign antigens from peripheral tissues to prime the adaptive immune response. Juxtaposed between innate and adaptive immune responses, the LN is an ideal site to study immune cell interactions1,2. Lymphocytes (T cells, B cells and NK cells), dendritic cells (DCs), and macrophages comprise the bulk of bone marrow-derived cellular elements of the LN. These cells are strategically positioned in the LN to allow efficient surveillance of self antigens and potential foreign antigens3-5. The process by which lymphocytes successfully encounter cognate antigens is a subject of intense investigation in recent years, and involves an integration of molecular contacts including antigen receptors, adhesion molecules, chemokines, and stromal structures such as the fibro-reticular network2,6-12. 
Prior to the development of high-resolution real-time fluorescent in vivo imaging, investigators relied on static imaging, which only offers answers regarding morphology, position, and architecture. While these questions are fundamental in our understanding of immune cell behavior, the limitations intrinsic with this technique does not permit analysis to decipher lymphocyte trafficking and environmental clues that affect dynamic cell behavior. Recently, the development of intravital two-photon laser scanning microscopy (2P-LSM) has allowed investigators to view the dynamic movements and interactions of individual cells within live LNs in situ12-16. In particular, we and others have applied this technique to image cellular behavior and interactions within the popliteal LN, where its compact, dense nature offers the advantage of multiplex data acquisition over a large tissue area with diverse tissue sub-structures11,17-18. It is important to note that this technique offers added benefits over explanted tissue imaging techniques, which require disruption of blood, lymph flow, and ultimately the cellular dynamics of the system. Additionally, explanted tissues have a very limited window of time in which the tissue remains viable for imaging after explant. With proper hydration and monitoring of the animal's environmental conditions, the imaging time can be significantly extended with this intravital technique. Here, we present a detailed method of preparing mouse popliteal LN for the purpose of performing intravital imaging.

Recent advances in 2-photon microscopy have enabled real-time in situ imaging of live tissues in animal models, thereby enhancing our ability to investigate cellular behavior in both physiologic and pathologic conditions. Here, we outline the preparations required to perform intravital imaging of the mouse popliteal lymph node.

Lymph nodes (LNs) are secondary lymphoid organs, which are strategically located throughout the body to allow for trapping and presentation of foreign ...

Isolation and Characterization of Dendritic Cells and Macrophages from the Mouse Intestine

Within the intestine reside unique populations of innate and adaptive immune cells that are involved in promoting tolerance towards commensal flora and food antigens while concomitantly remaining poised to mount inflammatory responses toward invasive pathogens1,2. Antigen presenting cells, particularly DCs and macrophages, play critical roles in maintaining intestinal immune homeostasis via their ability to sense and appropriately respond to the microbiota3-14. Efficient isolation of intestinal DCs and macrophages is a critical step in characterizing the phenotype and function of these cells. While many effective methods of isolating intestinal immune cells, including DCs and macrophages, have been described6,10,15-24, many rely upon long digestions times that may negatively influence cell surface antigen expression, cell viability, and/or cell yield. Here, we detail a methodology for the rapid isolation of large numbers of viable, intestinal DCs and macrophages. Phenotypic characterization of intestinal DCs and macrophages is carried out by directly staining isolated intestinal cells with specific fluorescence-labeled monoclonal antibodies for multi-color flow cytometric analysis. Furthermore, highly pure DC and macrophage populations are isolated for functional studies utilizing CD11c and CD11b magnetic-activated cell sorting beads followed by cell sorting.

Here, we detail a methodology for the rapid isolation of mouse intestinal dendritic cells (DCs) and macrophages. Phenotypic characterization of intestinal DCs and macrophages is performed using multi-color flow cytometric analysis while magnetic bead enrichment followed by cell sorting is used to yield highly pure populations for functional studies.

Within the intestine reside unique populations of innate and adaptive immune cells that are involved in promoting tolerance towards commensal flora and ...

Non-invasive Optical Imaging of the Lymphatic Vasculature of a Mouse

The lymphatic vascular system is an important component of the circulatory system that maintains fluid homeostasis, provides immune surveillance, and mediates fat absorption in the gut. Yet despite its critical function, there is comparatively little understanding of how the lymphatic system adapts to serve these functions in health and disease1. Recently, we have demonstrated the ability to dynamically image lymphatic architecture and lymph "pumping" action in normal human subjects as well as in persons suffering lymphatic dysfunction using trace administration of a near-infrared fluorescent (NIRF) dye and a custom, Gen III-intensified imaging system2-4. NIRF imaging showed dramatic changes in lymphatic architecture and function with human disease. It remains unclear how these changes occur and new animal models are being developed to elucidate their genetic and molecular basis. In this protocol, we present NIRF lymphatic, small animal imaging5,6 using indocyanine green (ICG), a dye that has been used for 50 years in humans7, and a NIRF dye-labeled cyclic albumin binding domain (cABD-IRDye800) peptide that preferentially binds mouse and human albumin8. Approximately 5.5 times brighter than ICG, cABD-IRDye800 has a similar lymphatic clearance profile and can be injected in smaller doses than ICG to achieve sufficient NIRF signals for imaging8. Because both cABD-IRDye800 and ICG bind to albumin in the interstitial space8, they both may depict active protein transport into and within the lymphatics. Intradermal (ID) injections (5-50 &mu;l) of ICG (645 &mu;M) or cABD-IRDye800 (200 &mu;M) in saline are administered to the dorsal aspect of each hind paw and/or the left and right side of the base of the tail of an isoflurane-anesthetized mouse. The resulting dye concentration in the animal is 83-1,250 &mu;g/kg for ICG or 113-1,700 &mu;g/kg for cABD-IRDye800. Immediately following injections, functional lymphatic imaging is conducted for up to 1 hr using a customized, small animal NIRF imaging system. Whole animal spatial resolution can depict fluorescent lymphatic vessels of 100 microns or less, and images of structures up to 3 cm in depth can be acquired9. Images are acquired using V++ software and analyzed using ImageJ or MATLAB software. During analysis, consecutive regions of interest (ROIs) encompassing the entire vessel diameter are drawn along a given lymph vessel. The dimensions for each ROI are kept constant for a given vessel and NIRF intensity is measured for each ROI to quantitatively assess "packets" of lymph moving through vessels.

Recently developed imaging techniques using near-infrared fluorescence (NIRF) may help elucidate the role the lymphatic system plays in cancer metastasis, immune response, wound repair, and other lymphatic-associated diseases.

The lymphatic  vascular system is an important component of the circulatory system that  maintains fluid homeostasis, provides immune surveillance, and ...

Isolation of Lymphocytes from Mouse Genital Tract Mucosa

Mucosal surfaces, including in the gastrointestinal, urogenital, and respiratory tracts, provide portals of entry for pathogens, such as viruses and bacteria 1. Mucosae are also inductive sites in the host to generate immunity against pathogens, such as the Peyers patches in the intestinal tract and the nasal-associated lymphoreticular tissue in the respiratory tract. This unique feature brings mucosal immunity as a crucial player of the host defense system. Many studies have been focused on gastrointestinal and respiratory mucosal sites. However, there has been little investigation of reproductive mucosal sites. The genital tract mucosa is the primary infection site for sexually transmitted diseases (STD), including bacterial and viral infections. STDs are one of the most critical health challenges facing the world today. Centers for Disease Control and Prevention estimates that there are 19 million new infectious every year in the United States. STDs cost the U.S. health care system $17 billion every year 2, and cost individuals even more in immediate and life-long health consequences. In order to confront this challenge, a greater understanding of reproductive mucosal immunity is needed and isolating lymphocytes is an essential component of these studies. Here, we present a method to reproducibly isolate lymphocytes from murine female genital tracts for immunological studies that can be modified for adaption to other species. The method described below is based on one mouse.&#x2003;

An efficient way to isolate lymphocytes from mouse genital tract is described. This method takes advantage of enzyme digestion and Percoll gradient separation to allow efficient isolation. This technique is also adaptable to for use in other species

Mucosal surfaces, including in the gastrointestinal, urogenital, and respiratory tracts, provide portals of entry for pathogens, such as viruses and ...

Time-lapse 3D Imaging of Phagocytosis by Mouse Macrophages

Phagocytosis plays a key role in host defense, as well as in tissue development and maintenance, and involves rapid, receptor-mediated rearrangements of the actin cytoskeleton to capture, envelop and engulf large particles. Although phagocytic receptors, downstream signaling pathways, and effectors, such as Rho GTPases, have been identified, the dynamic cytoskeletal remodeling of specific receptor-mediated phagocytic events remain unclear. Four decades ago, two distinct mechanisms of phagocytosis, exemplified by Fc&#947; receptor (Fc&#947;R)- and complement receptor (CR)-mediated phagocytosis, were identified using scanning electron microscopy. Binding of immunoglobulin G (IgG)-opsonized particles to Fc&#947;Rs triggers the protrusion of thin membrane extensions, which initially form a so-called phagocytic cup around the particle before it becomes completely enclosed and retracted into the cell. In contrast, complement opsonized particles appear to sink into the phagocyte following binding to complement receptors. These two modes of phagocytosis, phagocytic cup formation and sinking in, have become well established in the literature. However, the distinctions between the two modes have become blurred by reports that complement receptor-mediated phagocytosis may induce various membrane protrusions. With the availability of high resolution imaging techniques, phagocytosis assays are required that allow real-time 3D (three dimensional) visualization of how specific phagocytic receptors mediate the uptake of individual particles. More commonly used approaches for the study of phagocytosis, such as end-point assays, miss the opportunity to understand what is happening at the interface of particles and phagocytes. Here we describe phagocytic assays, using time-lapse spinning disk confocal microscopy, that allow 3D imaging of single phagocytic events. In addition, we describe assays to unambiguously image Fc&#947; receptor- or complement receptor-mediated phagocytosis.

Here we describe methods using spinning disk confocal microscopy to image single phagocytic events by mouse resident peritoneal macrophages. The protocols can be extended to other phagocytic cells.

Phagocytosis plays a key role in host defense, as well as in tissue development and maintenance, and involves rapid, receptor-mediated rearrangements of ...

Isolation and Quantitative Evaluation of Brush Cells from Mouse Tracheas

Tracheal brush cells are cholinergic chemosensory epithelial cells poised to transmit signals from the airway lumen to the immune and nervous systems. They are part of a family of chemosensory epithelial cells which include tuft cells in the intestinal mucosa, brush cells in the trachea, and solitary chemosensory and microvillous cells in the nasal mucosa. Chemosensory cells in different epithelial compartments share key intracellular markers and a core transcriptional signature, but also display significant transcriptional heterogeneity, likely reflective of the local tissue environment. Isolation of tracheal brush cells from single cell suspensions is required to define the function of these rare epithelial cells in detail, but their isolation is challenging, potentially due to the close interaction between tracheal brush cells and nerve endings or due to airway-specific composition of tight and adherens junctions. Here, we describe a procedure for isolation of brush cells from mouse tracheal epithelium. The method is based on an initial separation of tracheal epithelium from the submucosa, allowing for a subsequent shorter incubation of the epithelial sheet with papain. This procedure offers a rapid and convenient solution for flow cytometric sorting and functional analysis of viable tracheal brush cells.

Brush cells are rare cholinergic chemosensory epithelial cells found in the na&#239;ve mouse trachea. Due to their limited numbers, ex vivo evaluation of their functional role in airway immunity and remodeling is challenging. We describe a method for isolation of tracheal brush cells by flow cytometry.

Tracheal brush cells are cholinergic chemosensory epithelial cells poised to transmit signals from the airway lumen to the immune and nervous systems. ...