Name: isolation and staining of mouse skin keratinocytes for cell cycle specific analysis of cellular protein expression by mass cytometry
Uploaded: 2019-05-09T13:30:00
Description: Watch this Scientific Journal Video about Isolation and Staining of Mouse Skin Keratinocytes for Cell Cycle Specific Analysis of Cellular Protein Expression by Mass Cytometry at JoVE.com

Support for this work came from the Department of Dermatology, the Gates Center for Regenerative Medicine at the University of Colorado and&#160;University of Colorado (UC) Skin Disease Center Morphology and Phenotyping Cores (NIAMS P30 AR057212). The authors acknowledge the UC Cancer Center Flow Cytometry Shared Resource and support grant (NCI P30 CA046934) for the operation of the mass cytometer and are grateful for Karen Helm and Christine Childs at the core for their expert advice on flow and mass cytometric techniques.

The University of Colorado Anschutz Medical Campus&#39; Institutional Animal Care and Use Committee approved the animal experiments described in this protocol.
1. Preparations
<ol>
	<li>Design a metal-tagged antibody panel. Use the free online panel design software12 and include 127IododeoxyUridine (IdU), 164Dy (Dysprosium) labeled anti-CCNB1 (CYCLIN B1), 175Lu (Lutetium) phospho&#160;(p)-HISTONEH3Ser28 (pHH3), and 150<...

<ol>
	<li>Guzinska-Ustymowicz, K., Pryczynicz, A., Kemona, A., Czyzewska, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlation+between+proliferation+markers:+PCNA,+Ki-67,+MCM-2+and+antiapoptotic+protein+Bcl-2+in+colorectal+cancer.">Correlation between proliferation markers: PCNA, Ki-67, MCM-2 and antiapoptotic protein Bcl-2 in colorectal cancer.</a> Anticancer Research. 29 (8), 3049-3052 (2009).</li><li>Ladstein, R. G., Bachmann, I. M., Straume, O., Akslen, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ki-67+expression+is+superior+to+mitotic+count+and+novel+proliferation+markers+PHH3,+MCM4+and+mitosin+as+a+prognostic+factor+in+thick+cutaneous+melanoma.">Ki-67 expression is superior to mitotic count and novel proliferation markers PHH3, MCM4 and mitosin as a prognostic factor in thick cutaneous melanoma.</a> BioMedCentral Cancer. 10, 140 (2010).</li><li>Ryan, W. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activation+of+S6+signaling+is+associated+with+cell+survival+and+multinucleation+in+hyperplastic+skin+after+epidermal+loss+of+AURORA-A+Kinase.">Activation of S6 signaling is associated with cell survival and multinucleation in hyperplastic skin after epidermal loss of AURORA-A Kinase.</a> Cell Death &amp; Differentiation. , (2018).</li><li>Magaud, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Double+immunocytochemical+labeling+of+cell+and+tissue+samples+with+monoclonal+anti-bromodeoxyuridine.">Double immunocytochemical labeling of cell and tissue samples with monoclonal anti-bromodeoxyuridine.</a> Journal of Histochemistry &amp; Cytochemistry. 37 (10), 1517-1527 (1989).</li><li>Dolbeare, F., Gratzner, H., Pallavicini, M. G., Gray, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+cytometric+measurement+of+total+DNA+content+and+incorporated+bromodeoxyuridine.">Flow cytometric measurement of total DNA content and incorporated bromodeoxyuridine.</a> Proc Natl Acad Sci U S A. 80 (18), 5573-5577 (1983).</li><li>Toth, Z. E., Mezey, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+visualization+of+multiple+antigens+with+tyramide+signal+amplification+using+antibodies+from+the+same+species.">Simultaneous visualization of multiple antigens with tyramide signal amplification using antibodies from the same species.</a> Journal of Histochemistry &amp; Cytochemistry. 55 (6), 545-554 (2007).</li><li>Stack, E. C., Wang, C., Roman, K. A., Hoyt, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiplexed+immunohistochemistry,+imaging,+and+quantitation:+a+review,+with+an+assessment+of+Tyramide+signal+amplification,+multispectral+imaging+and+multiplex+analysis.">Multiplexed immunohistochemistry, imaging, and quantitation: a review, with an assessment of Tyramide signal amplification, multispectral imaging and multiplex analysis.</a> Methods. 70 (1), 46-58 (2014).</li><li>Kraemer, P. M., Petersen, D. F., Van Dilla, 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=DNA+constancy+in+heteroploidy+and+the+stem+line+theory+of+tumors.">DNA constancy in heteroploidy and the stem line theory of tumors.</a> Science. 174 (4010), 714-717 (1971).</li><li>Dolbeare, F., Gratzner, H., Pallavicini, M. G., Gray, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+cytometric+measurement+of+total+DNA+content+and+incorporated+bromodeoxyuridine.">Flow cytometric measurement of total DNA content and incorporated bromodeoxyuridine.</a> Proceedings of the National Academy of Sciences U S A. 80 (18), 5573-5577 (1983).</li><li>Bandura, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mass+cytometry:+technique+for+real+time+single+cell+multitarget+immunoassay+based+on+inductively+coupled+plasma+time-of-flight+mass+spectrometry.">Mass cytometry: technique for real time single cell multitarget immunoassay based on inductively coupled plasma time-of-flight mass spectrometry.</a> Analytical Chemistry. 81 (16), 6813-6822 (2009).</li><li>Bjornson, Z. B., Nolan, G. P., Fantl, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-cell+mass+cytometry+for+analysis+of+immune+system+functional+states.">Single-cell mass cytometry for analysis of immune system functional states.</a> Current Opinion in Immunology. 25 (4), 484-494 (2013).</li><li>Behbehani, G. K., Bendall, S. C., Clutter, M. R., Fantl, W. J., Nolan, G. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-cell+mass+cytometry+adapted+to+measurements+of+the+cell+cycle.">Single-cell mass cytometry adapted to measurements of the cell cycle.</a> Cytometry A. 81 (7), 552-566 (2012).</li><li>Brodie, T. M., Tosevski, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-Dimensional+Single-Cell+Analysis+with+Mass+Cytometry.">High-Dimensional Single-Cell Analysis with Mass Cytometry.</a> Current Protocols in Immunology. 118, 5.11.11-15.11.25 (2017).</li><li>McCarthy, R. L., Duncan, A. D., Barton, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sample+Preparation+for+Mass+Cytometry+Analysis.">Sample Preparation for Mass Cytometry Analysis.</a> Journal of Visual Experimentation. 122, (2017).</li><li>Lichti, U., Anders, J., Yuspa, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+short-term+culture+of+primary+keratinocytes,+hair+follicle+populations+and+dermal+cells+from+newborn+mice+and+keratinocytes+from+adult+mice+for+in+vitro+analysis+and+for+grafting+to+immunodeficient+mice.">Isolation and short-term culture of primary keratinocytes, hair follicle populations and dermal cells from newborn mice and keratinocytes from adult mice for in vitro analysis and for grafting to immunodeficient mice.</a> Nature Protocols. 3 (5), 799-810 (2008).</li><li>Zhang, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defects+in+Stratum+Corneum+Desquamation+Are+the+Predominant+Effect+of+Impaired+ABCA12+Function+in+a+Novel+Mouse+Model+of+Harlequin+Ichthyosis.">Defects in Stratum Corneum Desquamation Are the Predominant Effect of Impaired ABCA12 Function in a Novel Mouse Model of Harlequin Ichthyosis.</a> PLoS One. 11 (8), e0161465 (2016).</li><li>Zunder, E. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Palladium-based+mass+tag+cell+barcoding+with+a+doublet-filtering+scheme+and+single-cell+deconvolution+algorithm.">Palladium-based mass tag cell barcoding with a doublet-filtering scheme and single-cell deconvolution algorithm.</a> Nature Protocols. 10 (2), 316-333 (2015).</li><li>Sumatoh, H. R., Teng, K. W., Cheng, Y., Newell, E. W. <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+mass+cytometry+sample+cryopreservation+after+staining.">Optimization of mass cytometry sample cryopreservation after staining.</a> Cytometry A. 91 (1), 48-61 (2017).</li><li>Finck, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Normalization+of+mass+cytometry+data+with+bead+standards.">Normalization of mass cytometry data with bead standards.</a> Cytometry A. 83 (5), 483-494 (2013).</li><li>Trowbridge, I. S., Thomas, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CD45:+an+emerging+role+as+a+protein+tyrosine+phosphatase+required+for+lymphocyte+activation+and+development.">CD45: an emerging role as a protein tyrosine phosphatase required for lymphocyte activation and development.</a> Annual Review of Immunology. 12, 85-116 (1994).</li><li>Torchia, E. C., Boyd, K., Rehg, J. E., Qu, C., Baker, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EWS/FLI-1+induces+rapid+onset+of+myeloid/erythroid+leukemia+in+mice.">EWS/FLI-1 induces rapid onset of myeloid/erythroid leukemia in mice.</a> Molecular and Cellular Biology. 27 (22), 7918-7934 (2007).</li><li>Liu, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Simplified+and+Efficient+Method+to+Isolate+Primary+Human+Keratinocytes+from+Adult+Skin+Tissue.">A Simplified and Efficient Method to Isolate Primary Human Keratinocytes from Adult Skin Tissue.</a> Journal of Visual Experimentation. (138), (2018).</li><li>Jensen, K. B., Driskell, R. R., Watt, F. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assaying+proliferation+and+differentiation+capacity+of+stem+cells+using+disaggregated+adult+mouse+epidermis.">Assaying proliferation and differentiation capacity of stem cells using disaggregated adult mouse epidermis.</a> Nature Protocols. 5 (5), 898-911 (2010).</li><li>Germain, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improvement+of+human+keratinocyte+isolation+and+culture+using+thermolysin.">Improvement of human keratinocyte isolation and culture using thermolysin.</a> Burns. 19 (2), 99-104 (1993).</li><li>Fluhr, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+anatomical+location+on+barrier+recovery,+surface+pH+and+stratum+corneum+hydration+after+acute+barrier+disruption.">Impact of anatomical location on barrier recovery, surface pH and stratum corneum hydration after acute barrier disruption.</a> British Journal of Dermatology. 146 (5), 770-776 (2002).</li><li>Webb, A., Li, A., Kaur, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Location+and+phenotype+of+human+adult+keratinocyte+stem+cells+of+the+skin.">Location and phenotype of human adult keratinocyte stem cells of the skin.</a> Differentiation. 72 (8), 387-395 (2004).</li><li>Torchia, E. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+genetic+variant+of+Aurora+kinase+A+promotes+genomic+instability+leading+to+highly+malignant+skin+tumors.">A genetic variant of Aurora kinase A promotes genomic instability leading to highly malignant skin tumors.</a> Cancer Research. 69 (18), 7207-7215 (2009).</li><li>Frei, A. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+multiplexed+simultaneous+detection+of+RNAs+and+proteins+in+single+cells.">Highly multiplexed simultaneous detection of RNAs and proteins in single cells.</a> Nature Methods. 13 (3), 269-275 (2016).</li></ol>

The protocol outlined in this paper can be completed in about 8 h. The end result is a suspension of cells enriched in KCs that can be analyzed for protein expression in a cell cycle-dependent manner. Several previous studies have outlined methods to isolate KCs from human and mouse skin16,25. These studies also include protocols for the isolation of KCs for flow cytometry26. However, a detailed protocol has not been previously described t...

Correlation of&#160;gene expression with cell cycle stages remains a challenge in the analysis of animal models of hyperplastic diseases like cancer. Part of this challenge is the co-detection of proteins of interest (POI) with markers of proliferation. Proliferative cells can be found in various cell cycle phases including G1, S, G2, and M. Ki67 is one of most commonly used markers of proliferation and is expressed in all phases of the cell cycle. It has been extensively used in the analysis of both human and mouse tissues1,2,3. However, like other general proliferation markers, Ki67 does not discern individual cell cycle phases. A more precise approach uses the incorporation of thymidine nucleotide analogs like Bromodeoxyuridine (BrdU) into cells that are actively replicating their genome (i.e., S-phase)4,5. One drawback to the use of nucleotide analogs is the need to administer them to live animals hours before analysis. Ki67 and BrdU are commonly detected on fixed tissue sections by the use of antibodies. One advantage of this approach is that the location of POIs can be ascertained within the tissue architecture (e.g., the basal layer of skin epidermis). This approach also does not require tissue dissociation that may lead to changes in gene expression. One disadvantage is that the tissue fixation or the processing of the tissue for OCT frozen or paraffin sectioning may occlude antibody targets (i.e., antigens). Retrieval of antigens typically requires heat or tissue digestion. Quantification of staining intensities can also be challenging. This is due to variations in staining, section thickness, signal detection, and experimenter bias. Moreover, a limited number of markers can be detected simultaneously in most typical laboratory setups. Yet, newer multiplex staining approaches promise to overcome these limitations; examples are imaging mass cytometry and Tyramide signal amplification6,7.
Flow cytometry is another powerful technology to detect proliferating cells. It allows for multiplex detection of markers in the same cells but requires tissue dissociation for most non-hematopoietic cell types. Analysis of proliferating cells is routinely done by the use of dyes that bind DNA (e.g., Propidium Iodide (PI))8. Flow cytometry also permits a more precise determination of cell cycle phases when coupled with the detection of BrdU incorporation9. Although a powerful approach, BrdU/PI flow cytometry does have its disadvantages. It is unable to resolve the G2/M and G0/G1 phases without the inclusion of phase-specific antibodies. However, the number of antibodies that can be used is limited by cellular autofluorescence, spectral spillover of fluorophore emissions, and the use of compensation controls. This limitation markes it more challenging and laborious to co-detect the expression of cell cycle markers with POIs. A more facile approach is to use mass cytometry10,11. This technology uses metal conjugated antibodies that have a narrower detection spectrum. Once cells are stained with metal-tagged antibodies, they are vaporized, and the metals detected by cytometry time-of-flight (CyTOF) mass spectrometry. Due to these properties, mass cytometry enables the multiplex detection of &#62;40 different markers using existing platforms10,11. In addition, it is possible to barcode samples with metals that result in the savings of precious antibodies while reducing sample-to-sample staining variability. On the other hand, mass cytometry does have several disadvantages. There are a limited number of commercially available metal-tagged antibodies for non-blood derived cells. Quantification of DNA content is less sensitive compared to the use of fluorescent DNA dyes and mass cytometry has a reduced dynamic range of signal detection compared to fluorescence flow cytometry.
The protocol described here was designed to analyze cell cycle dynamics from newly isolated keratinocytes (KCs) from mouse skin and characterize cell cycle specific protein expression in these cells using mass cytometry. This protocol can also be used with cultured cells or adapted to other cell types.

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	<tbody>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">12-well plate</td>
			<td style="width:237px;">Cell Treat</td>
			<td style="width:259px;">229512</td>
			<td style="width:368px;"></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Intercalator solution</td>
			<td style="width:237px;">Fluidigm</td>
			<td style="width:259px;">201192A</td>
			<td>125 &#181;M - Ir intercalator solution</td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">Paraformaldehyde</td>
			<td style="width:237px;">Electron Microscopy Sciences</td>
			<td style="width:259px;">30525-89-4</td>
			<td>16 %&#160; PFA</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Strainer cap flow tubes</td>
			<td style="width:237px;">Fisher/Corning</td>
			<td style="width:259px;">352235</td>
			<td>35 &#181;m pore size&#160;</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Cell sieve</td>
			<td style="width:237px;">Fisher</td>
			<td style="width:259px;">22363547</td>
			<td>40 &#956;m pore size&#160;</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Cell detatchment solution</td>
			<td style="width:237px;">CELLnTEC</td>
			<td style="width:259px;">CnT-ACCUTASE-100</td>
			<td>Accutase</td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">Iodine Solution</td>
			<td style="width:237px;">ThermoFisher/Purdue</td>
			<td style="width:259px;">67618-151-17</td>
			<td>Betadine 7.5%-iodine surgical scrub</td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">Barcode permeabilization buffer&#160;</td>
			<td style="width:237px;">Fluidigm</td>
			<td style="width:259px;">201060</td>
			<td style="width:368px;">Cell-ID 20-Plex Pd Barcoding Kit</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Barcodes</td>
			<td style="width:237px;">Fluidigm</td>
			<td style="width:259px;">201060</td>
			<td style="width:368px;">Cell-ID 20-Plex Pd Barcoding Kit</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">pH strips</td>
			<td style="width:237px;">EMD</td>
			<td style="width:259px;">9590</td>
			<td>colorpHast</td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">DMEM</td>
			<td style="width:237px;">Hyclone</td>
			<td style="width:259px;">SH30022.01</td>
			<td style="width:368px;">Dulbecco&#8217;s Modified Eagle Media</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;">Fine forceps</td>
			<td style="width:237px;">Dumont &#38; Fils</td>
			<td style="width:259px;">0109-5-PO</td>
			<td style="width:368px;">Dumostar #5</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;">Curved precision forceps</td>
			<td style="width:237px;">Dumont &#38; Fils</td>
			<td style="width:259px;">0109-7-PO</td>
			<td style="width:368px;">Dumostar #7</td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">Calibration Beads</td>
			<td style="width:237px;">Fluidigm</td>
			<td style="width:259px;">201078</td>
			<td style="width:368px;">EQ Four Element Calibration Beads</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">HBSS</td>
			<td style="width:237px;">Gibco</td>
			<td style="width:259px;">14175-095</td>
			<td>Hank&#39;s Balanced Salt Solution</td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">Water</td>
			<td style="width:237px;">Fisher</td>
			<td style="width:259px;">SH30538.03</td>
			<td style="width:368px;">Hyclone Molecular Biology grade water</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Iododeoxyuridine</td>
			<td style="width:237px;">&#160;Sigma</td>
			<td style="width:259px;">I7125</td>
			<td>IdU</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Cryo vials</td>
			<td style="width:237px;">ThermoFisher</td>
			<td style="width:259px;">366656PK</td>
			<td>internal thread</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Cell Staining buffer</td>
			<td style="width:237px;">Fluidigm</td>
			<td style="width:259px;">201068</td>
			<td style="width:368px;">Maxpar Cell Staining buffer</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Fix &#38; Perm buffer</td>
			<td style="width:237px;">Fluidigm</td>
			<td style="width:259px;">201067</td>
			<td style="width:368px;">Maxpar Fix &#38; Perm buffer</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Fix I buffer</td>
			<td style="width:237px;">Fluidigm</td>
			<td style="width:259px;">201065</td>
			<td style="width:368px;">Maxpar Fix I buffer</td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">Phosphate buffered saline</td>
			<td style="width:237px;">Rockland</td>
			<td style="width:259px;">MB-008</td>
			<td>Metal free 10x PBS</td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">isopropanol-freezing container</td>
			<td style="width:237px;">ThermoFisher</td>
			<td style="width:259px;">5100-0001</td>
			<td>Mr.Frosty</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Sodium hydroxide</td>
			<td style="width:237px;">Fisher</td>
			<td style="width:259px;">BP359-500</td>
			<td>NaOH</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Petri dish</td>
			<td style="width:237px;">Kord-Valmark</td>
			<td style="width:259px;">2900</td>
			<td>Supplied by Genesee 32-107&#160;</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">15 mL conical</td>
			<td style="width:237px;">Olympus/Genesee</td>
			<td style="width:259px;">28-101</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">50 mL conical</td>
			<td style="width:237px;">Olympus/Genesee</td>
			<td style="width:259px;">28-106</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">6-well plate</td>
			<td style="width:237px;">Cell Treat</td>
			<td style="width:259px;">229506</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Cisplatin</td>
			<td style="width:237px;">Sigma</td>
			<td style="width:259px;">479306</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Dispase II</td>
			<td style="width:237px;">Sigma/Roche</td>
			<td style="width:259px;">4942078001</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">DMSO</td>
			<td style="width:237px;">Sigma</td>
			<td style="width:259px;">D2650</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">FBS</td>
			<td style="width:237px;">Atlanta Biologicals</td>
			<td style="width:259px;">S11150</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Hydrochloric acid</td>
			<td style="width:237px;">Fisher</td>
			<td style="width:259px;">A144-212</td>
			<td></td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">Nuclear Antigen Staining&#160; permeabilization buffer</td>
			<td style="width:237px;">Fluidigm</td>
			<td style="width:259px;">201063</td>
			<td></td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">Nuclear Antigen Staining buffer</td>
			<td style="width:237px;">Fluidigm</td>
			<td style="width:259px;">201063</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:293px;">Trypan blue</td>
			<td style="width:237px;">Sigma</td>
			<td style="width:259px;">T8154</td>
			<td></td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">Tuberculin syringe</td>
			<td style="width:237px;">BD</td>
			<td style="width:259px;">309626</td>
			<td></td>
		</tr>
		<tr height="70">
			<td height="70" style="height:70px;width:293px;">Type IV Collagenase&#160;</td>
			<td style="width:237px;">Worthington Bioscience</td>
			<td style="width:259px;">CLSS-4</td>
			<td></td>
		</tr>
	</tbody>
</table>

isolation and staining of mouse skin keratinocytes for cell cycle specific analysis of cellular protein expression by mass cytometry

The goal of this protocol is to detect and quantify protein expression changes in a cell cycle-dependent manner using single cells isolated from the epidermis of mouse skin. There are seven important steps: separation of the epidermis from the dermis, digestion of the epidermis, staining of the epidermal cell populations with cisplatin, sample barcoding, staining with metal tagged antibodies for cell cycle markers and proteins of interest, detection of metal-tagged antibodies by mass cytometry, and the analysis of expression in the various cell cycle phases. The advantage of this approach over histological methods is the potential to assay the expression pattern of &#62;40 different markers in a single cell at different phases of the cell cycle. This approach also allows for the multivariate correlation analysis of protein expression that is more quantifiable than histological/imaging methods. The disadvantage of this protocol is that a suspension of single cells is needed, which results in the loss of location information provided by the staining of tissue sections. This approach may also require the inclusion of additional markers to identify different cell types in crude cell suspensions. The application of this protocol is evident in the analysis of hyperplastic skin disease models. Moreover, this protocol can be adapted for the analysis of specific sub-type of cells (e.g., stem cells) by the addition of lineage-specific antibodies. This protocol can also be adapted for the analysis of skin cells in other experimental species.

Table 1 shows the expected cell yields and viability from adult mouse ear (Figure 1) and neonatal skin under non-pathological conditions. The table also shows representative data of animals from a mixed C57/126 background. It is expected that the skin of other strains would result in similar cell yields and viabilities. The approximate yield is dependent on the surface area of skin and indicates that neonatal skin would be a better choice for...

Watch this Scientific Journal Video about Isolation and Staining of Mouse Skin Keratinocytes for Cell Cycle Specific Analysis of Cellular Protein Expression by Mass Cytometry at JoVE.com

Isolation and Staining of Mouse Skin Keratinocytes for Cell Cycle Specific Analysis of Cellular Protein Expression by Mass Cytometry

This protocol describes how to isolate skin keratinocytes from mouse models, to stain with metal-tagged antibodies, and to analyze stained cells by mass cytometry in order to profile the expression pattern of proteins of interest in the different cell cycle phases.

The goal of this protocol is to detect and quantify protein expression changes in a cell cycle-dependent manner using single cells isolated from the ...

This protocol is significant for two main reasons. Number one, it allows a user to be able to determine the cell cycle states of skin cells that have been isolated from an animal model. It also allows us to be able to analyze protein expression in the discrete phases of the cell cycle.Compared to previous methods of determining cell proliferation, our method permits a more precise determination of the different phases in the cell cycle, and we can also analyze greater than 40 different markers in the various stages of cell division. This greatly enhances the application and versatility of the method. This protocol may be used in cancer research and in any other type of disease where there's a need to determine cell cycle specific protein expression patterns.In addition, this protocol can be modified to other cell types, and in other model organisms. The first time user should focus on getting the best quality cell preparation possible. This requires the timely processing of experimental skin using fresh reagents, minimal tissue digestion time, and careful disposal of the supernatant after centrifugation to preserve the integrity and quantity of cells.To begin, design a metal-tagged antibody panel using a free online panel design software, as described in the manuscript. Then prepare an IdU stock solution by dissolving IdU powder at 10 milligrams per milliliter in 0.1 normal sodium hydroxide at 60 degrees Celsius. After aliquoting IdU stock solution into microcentrifuge tubes, freeze them at minus 20 degrees Celsius for long-term storage.Immediately before use, adjust the pH of the IdU solution to 7.5 with 12 normal hydrochloric acid, and test with a pH strip on a discard aliquot to ensure the solution is at pH 7.5. To prepare a two x paraformaldehyde fixing solution, combine five milliliters of 10 x PBS and one milliliter of 16%PFA with 44 milliliters of pure molecular-grade distilled water. To prepare 100 millimolar cisplatin stock solution, dissolve 300.5 milligrams of cisplatin powder in 10 milliliters of DMSO.For experiments to be used over one day, prepare a 10 millimolar cisplatin working solution. Weigh mice and then determine a dose at 0.1 milligrams of IdU per gram of body weight. Administer the calculated dose of IDU by an intraperitoneal injection, and wait for two hours before harvesting cells.Use a pair of surgical grade scissors to surgically remove the ear of the euthanized mouse previously injected with IdU at the base of the ear. Place the ear on a dry 100 millimeter Petri dish. Carefully separate the anterior from the posterior skin by using fine forceps to create a pocket in the middle or edge of the cut area, then pull the two skin flaps apart, and proceed with both the anterior and posterior skins.Carefully place the anterior and posterior skins of one ear in one well of a 12-well culture plate, filled with one milliliter of freshly-prepared dispase/collagenase solution, with the derma side of the skin touching the solution. Incubate at 37 degrees Celsius for one hour to digest the skin. Place the digested ear or neonatal skin in a clean Petri dish with the epidermis side touching the surface of the dish.Using forceps, flatten out the skin and gently slide the dermis off the epidermis by working from the center to the edges in a circular pattern. With forceps, grab the epidermis at the edges and gently lift it off by peeling it off the surface of the Petri dish. Carefully place the epidermis on pre-warmed cell detachment solution in one well of a plate.Incubate for five minutes at 37 degrees Celsius or 20 minutes at room temperature. Use sterile forceps to grasp the epidermis and scrub by dragging the epidermis against the bottom of the dish to dissociate cells. Add one milliliter of DMEM containing 1%FBS, and pass through a 40 micrometer cell sieve into a collection tube.Rinse well with an additional two milliliters of DMEM and add to the cell suspension. After centrifuging at 120 times g for five minutes, carefully aspirate the supernatant. Resuspend the cell pellet in one to two milliliters of DMEM containing 1%FBS, and pellet the cells again as previously.To label cells to determine live and dead cells, resuspend one to three million cells in one milliliter of DMEM containing 25 micromolar cisplatin and incubate for one minute. Quench by pipetting with an equal volume of FBS. After centrifuging at 120 times g for five minutes, decant the supernatant into a beaker containing diluted bleach, and invert the tubes to drain the remaining solution onto a paper towel.Resuspend the cell pellet in two milliliters of barium cation-free PBS, and centrifuge them again as previously described. To fix the cells, resuspend the cell pellet in one milliliter of barium cation-free PBS. Vortex the cells under continuous low power and add one milliliter of the two x PFA fixation buffer drop-wise.Place on a rocking platform and incubate at room temperature for 10 minutes. After centrifuging at 500 times g for five minutes, carefully decant the supernatant. Wash the cells with two milliliters of barium cation-free PBS, centrifuge again under the same conditions, and repeat the washing step.Finally, resuspend the pellet in two milliliters of barium cation-free PBS. Centrifuge the cells at 500 times g for five minutes and carefully decant the supernatant. Resuspend the cells in one milliliter of one x fixation buffer, and incubate at room temperature for 10 minutes and repeat the centrifugation.To wash the cells, add one milliliter of barcode permeabilization buffer. During cell centrifugation at 500 times g for five minutes, prepare barcodes by adding 100 microliters of barcode permeabilization buffer to them, and mix immediately. Resuspend the cell pellet in 800 microliters of barcode permeabilization buffer.Add barcode solution to the cells, mix, and incubate at room temperature for 30 minutes. Centrifuge at 500 times g for five minutes. Wash cells in two milliliters of cell staining buffer and centrifuge again.Next, resuspend one to three million cells in one milliliter of nuclear antigen staining buffer working solution, and incubate at room temperature for 30 minutes. After centrifuging at 500 times g for five minutes, carefully decant the supernatant. Resuspend the cells in one milliliter of nuclear antigen staining permeabilization buffer and centrifuge again.After repeat resuspension and centrifugation, resuspend the cell pellet in the residual volume with gentle vortexing. Add 50 microliters of intracellular antibody cocktail, mix, and incubate at room temperature for 45 minutes. Add two milliliters of cell staining buffer.Centrifuge again under the same conditions as in the previous step, and remove the supernatant. Resuspend the pellet in two milliliters of cell staining buffer, centrifuge at 500 times g for five minutes, and repeat the resuspending and centrifugation. Resuspend the cells in one milliliter of intercalation solution, and store for one to three days at four degrees Celsius.After centrifuging the cells again, wash the pellet with two milliliters of cell staining buffer, centrifuge under the same conditions, and perform two additional washes with two milliliters of water, with the same centrifugation. Resuspend the cell pellet at a concentration of one million cells per milliliter with diluted EQ bead solution, and then run the samples on the mass cytometer. Expected cell yields and viability from adult mouse ear and neonatal skin are determined.The approximate yield depends on the surface area of the skin. Neonatal skin is a better choice for experiments that require larger numbers of cells. The basic gating strategy to select for intact, single, and viable cells, after normalization and deconvolution of barcoded mass cytometry data, is shown.The percentage of viable cells may be indicative of the quality or condition of the cells prior to staining. Differences in viability between cultured carcinoma cells versus isolated mouse ear cells are shown, too. Viable cells were gated on event length versus CD45 to exclude hematopoietic cells.The inclusion of lineage markers allows for the selection of cell populations of interest in different cell cycle phases. The basic cell cycle profile is obtained by the detection of BrdU versus PI in fluorescent-based flow cytometry. However, inclusion of other proliferation markers with mass cytometry, allows a more precise identification of cell cycle phases.Following this approach, cell cycle profiles can be constructed for different cell types or experimental conditions, such as the profiles for CD45 negative versus CD45 positive cells from the same experiment. In another example, analysis of markers that define the EGFR and mTOR PI3K signaling pathways in the G-one phase, revealed similar expression profiles in CD45 negative cells, shown in orange, and CD45 positive cells, shown in blue. Mass cytometry requires a lot of high-quality cells.If a user is interested in a rare cell population, higher numbers of cells may be needed. Isolated live cells can be used for DNA or RNA analysis, biochemical studies, or can be used in tissue culture prior to the fixation and staining for mass cytometry. The user should use personal protection equipment and a safety cabinet when necessary, when working with paraformaldehyde, hydrochloric acid, or sodium hydroxide.

isolation-staining-mouse-skin-keratinocytes-for-cell-cycle-specific

Research

JoVE Journal

Developmental Biology

3D Organotypic Co-culture Model Supporting Medullary Thymic Epithelial Cell Proliferation, Differentiation and Promiscuous Gene Expression

Intra-thymic T cell development requires an intricate three-dimensional meshwork composed of various stromal cells, i.e., non-T cells. Thymocytes traverse this scaffold in a highly coordinated temporal and spatial order while sequentially passing obligatory check points, i.e., T cell lineage commitment, followed by T cell receptor repertoire generation and selection prior to their export into the periphery. The two major resident cell types forming this scaffold are cortical (cTECs) and medullary thymic epithelial cells (mTECs). A key feature of mTECs is the so-called promiscuous expression of numerous tissue-restricted antigens. These tissue-restricted antigens are presented to immature thymocytes directly or indirectly by mTECs or thymic dendritic cells, respectively resulting in self-tolerance.
Suitable in vitro models emulating the developmental pathways and functions of cTECs and mTECs are currently lacking. This lack of adequate experimental models has for instance hampered the analysis of promiscuous gene expression, which is still poorly understood at the cellular and molecular level. We adapted a 3D organotypic co-culture model to culture ex vivo isolated mTECs. This model was originally devised to cultivate keratinocytes in such a way as to generate a skin equivalent in vitro. The 3D model preserved key functional features of mTEC biology: (i) proliferation and terminal differentiation of CD80lo, Aire-negative into CD80hi, Aire-positive mTECs, (ii) responsiveness to RANKL, and (iii) sustained expression of FoxN1, Aire and tissue-restricted genes in CD80hi mTECs.

Studying medullary thymic epithelial cells in vitro has been largely unsuccessful, as current 2D culture systems do not mimic the in vivo scenario. The 3D culture system described herein - a modified skin organotypic culture model - has proven superior in recapitulating mTEC proliferation, differentiation and maintenance of promiscuous gene expression.

Intra-thymic T cell development requires an intricate three-dimensional meshwork composed of various stromal cells, i.e., non-T cells. Thymocytes traverse ...

Generation of Genetically Modified Organotypic Skin Cultures Using Devitalized Human Dermis

Organotypic cultures allow the reconstitution of a 3D environment critical for cell-cell contact and cell-matrix interactions which mimics the function and physiology of their in vivo tissue counterparts. This is exemplified by organotypic skin cultures which faithfully recapitulates the epidermal differentiation and stratification program. Primary human epidermal keratinocytes are genetically manipulable through retroviruses where genes can be easily overexpressed or knocked down. These genetically modified keratinocytes can then be used to regenerate human epidermis in organotypic skin cultures providing a powerful model to study genetic pathways impacting epidermal growth, differentiation, and disease progression. The protocols presented here describe methods to prepare devitalized human dermis as well as to genetically manipulate primary human keratinocytes in order to generate organotypic skin cultures. Regenerated human skin can be used in downstream applications such as gene expression profiling, immunostaining, and chromatin immunoprecipitations followed by high throughput sequencing. Thus, generation of these genetically modified organotypic skin cultures will allow the determination of genes that are critical for maintaining skin homeostasis.

The goal of this paper is to provide a comprehensive and detailed protocol on how to generate genetically modified human organotypic skin from epidermal keratinocytes and devitalized human dermis.

Organotypic cultures allow the reconstitution of a 3D environment critical for cell-cell contact and cell-matrix interactions which mimics the function ...

Step-specific Sorting of Mouse Spermatids by Flow Cytometry

The differentiation of mouse spermatids is one critical process for the production of a functional male gamete with an intact genome to be transmitted to the next generation. So far, molecular studies of this morphological transition have been hampered by the lack of a method allowing adequate separation of these important steps of spermatid differentiation for subsequent analyses. Earlier attempts at proper gating of these cells using flow cytometry may have been difficult because of a peculiar increase in DNA fluorescence in spermatids undergoing chromatin remodeling. Based on this observation, we provide details of a simple flow cytometry scheme, allowing reproducible purification of four populations of mouse spermatids fixed with ethanol, each representing a different state in the nuclear remodeling process. Population enrichment is confirmed using step-specific markers and morphological criterions. The purified spermatids can be used for genomic and proteomic analyses.

We describe a sorting strategy for mouse spermatids using flow cytometry. Spermatids are sorted into four highly pure populations, including round (spermiogenesis steps 1-9), early elongating (spermiogenesis steps 10-12), late elongating (spermiogenesis steps 13-14) and elongated spermatids (spermiogenesis steps 15-16). DNA staining, size and granulosity are used as selection parameters.

The differentiation of mouse spermatids is one critical process for the production of a functional male gamete with an intact genome to be transmitted to ...

Quantitative Analysis of Protein Expression to Study Lineage Specification in Mouse Preimplantation Embryos

This protocol presents a method to perform quantitative, single-cell in situ analyses of protein expression to study lineage specification in mouse preimplantation embryos. The procedures necessary for embryo collection, immunofluorescence, imaging on a confocal microscope, and image segmentation and analysis are described. This method allows quantitation of the expression of multiple nuclear markers and the spatial (XYZ) coordinates of all cells in the embryo. It takes advantage of MINS, an image segmentation software tool specifically developed for the analysis of confocal images of preimplantation embryos and embryonic stem cell (ESC) colonies. MINS carries out unsupervised nuclear segmentation across the X, Y and Z dimensions, and produces information on cell position in three-dimensional space, as well as nuclear fluorescence levels for all channels with minimal user input. While this protocol has been optimized for the analysis of images of preimplantation stage mouse embryos, it can easily be adapted to the analysis of any other samples exhibiting a good signal-to-noise ratio and where high nuclear density poses a hurdle to image segmentation (e.g., expression analysis of embryonic stem cell (ESC) colonies, differentiating cells in culture, embryos of other species or stages, etc.).

This protocol presents a method to perform quantitative, single-cell in situ analysis of protein expression to study lineage specification in mouse preimplantation embryos. The procedures necessary for collection of blastocysts, whole-mount immunofluorescent detection of proteins, imaging of samples on a confocal microscope, and nuclear segmentation and image analysis are described.

This protocol presents a method to perform quantitative, single-cell in situ analyses of protein expression to study lineage specification in mouse ...

Isolating Hair Follicle Stem Cells and Epidermal Keratinocytes from Dorsal Mouse Skin

The hair follicle (HF) is an ideal system for studying the biology and regulation of adult stem cells (SCs). This dynamic mini organ is replenished by distinct pools of SCs, which are located in the permanent portion of the HF, a region known as the bulge. These multipotent bulge SCs were initially identified as slow cycling label retaining cells; however, their isolation has been made feasible after identification of specific cell markers, such as CD34 and keratin 15 (K15). Here, we describe a robust method for isolating bulge SCs and epidermal keratinocytes from mouse HFs utilizing fluorescence activated cell-sorting (FACS) technology. Isolated hair follicle SCs (HFSCs) can be utilized in various in vivo grafting models and are a valuable in vitro model for studying the mechanisms that govern multipotency, quiescence and activation.

An ideal model for studying adult stem cell biology is the mouse hair follicle. Here we present a protocol for isolating different populations of hair follicles stem cells and epidermal keratinocytes, employing enzymatic digestion of mouse dorsal skin followed by FACS analysis.

The hair follicle (HF) is an ideal system for studying the biology and regulation of adult stem cells (SCs). This dynamic mini organ is replenished by ...

Identification Of Erythromyeloid Progenitors And Their Progeny In The Mouse Embryo By Flow Cytometry

Macrophages are professional phagocytes from the innate arm of the immune system. In steady-state, sessile macrophages are found in adult tissues where they act as front line sentinels of infection and tissue damage. While other immune cells are continuously renewed from hematopoietic stem and progenitor cells (HSPC) located in the bone marrow, a lineage of macrophages, known as resident macrophages, have been shown to be self-maintained in tissues without input from bone marrow HSPCs. This lineage is exemplified by microglia in the brain, Kupffer cells in the liver and Langerhans cells in the epidermis among others. The intestinal and colon lamina propria are the only adult tissues devoid of HSPC-independent resident macrophages. Recent investigations have identified that resident macrophages originate from the extra-embryonic yolk sac hematopoiesis from progenitor(s) distinct from fetal hematopoietic stem cells (HSC). Among yolk sac definitive hematopoiesis, erythromyeloid progenitors (EMP) give rise both to erythroid and myeloid cells, in particular resident macrophages. EMP are only generated within the yolk sac between E8.5 and E10.5 days of development and they migrate to the fetal liver as early as circulation is connected, where they expand and differentiate until at least E16.5. Their progeny includes erythrocytes, macrophages, neutrophils and mast cells but only EMP-derived macrophages persist until adulthood in tissues. The transient nature of EMP emergence and the temporal overlap with HSC generation renders the analysis of these progenitors difficult. We have established a tamoxifen-inducible fate mapping protocol based on expression of the macrophage cytokine receptor Csf1r promoter to characterize EMP and EMP-derived cells in vivo by flow cytometry.

While infiltrating macrophages are continuously recruited to adult tissues from circulating precursors, resident macrophages seed their tissue during development, where they are maintained without further input from progenitors. The progenitors for resident macrophages were recently identified. Here, we present methods for the genetic fate mapping of the resident macrophage progenitors.

Macrophages are professional phagocytes from the innate arm of the immune system. In steady-state, sessile macrophages are found in adult tissues where ...

Generation and Culturing of Primary Human Keratinocytes from Adult Skin

The main function of keratinocytes is to provide the structural integrity of the epidermis, thereby maintaining a mechanical barrier to the outside world. In addition, keratinocytes play an essential role in the initiation, maintenance, and regulation of epidermal immune responses by being part of the innate immune system responding to antigenic stimuli in a fast, nonspecific manner. Here, we describe a protocol for isolation of primary human keratinocytes from adult skin, and demonstrate that these cells respond to calcium-induced terminal differentiation, as measured by an increased expression of the differentiation marker involucrin. In addition, we show that the isolated keratinocytes are responsive to IL-1&#946;-induced activation of intracellular signaling pathways as measured by the activation of the p38 MAPK pathway. Taken together, we describe a method for isolation and culturing of primary human keratinocytes from adult skin. Because the keratinocytes are the predominant cell type in the epidermis, this method is useful to study molecular mechanisms in cutaneous biology in vitro.

The human skin acts as a first line of defense against the external environment. We present a method for isolating primary human keratinocytes from adult skin. These isolated keratinocytes are useful in numerous experimental setups, and are a highly suitable model for studying molecular mechanisms in cutaneous biology in vitro.

The main function of keratinocytes is to provide the structural integrity of the epidermis, thereby maintaining a mechanical barrier to the outside world. ...

A Simplified and Efficient Method to Isolate Primary Human Keratinocytes from Adult Skin Tissue

Primary human keratinocytes isolated from fresh skin tissues and their expansion in vitro have been widely used for laboratory research and for clinical applications. The conventional isolation method of human keratinocytes involves a two-step sequential enzymatic digestion procedure, which has been proven to be inefficient in generating primary cells from adult tissues due to the low cell recovery rate and reduced cell viability. We recently reported an advanced method to isolate human primary epidermal progenitor cells from skin tissues that utilizes the Rho kinase inhibitor Y-27632 in the medium. Compared with the traditional protocol, this new method is simpler, easier, and less time-consuming, and increases epithelial stem cell yield and enhances their stem cell characteristics. Moreover, the new methodology does not require the separation of the epidermis from the dermis, and, therefore, is suitable for isolating cells from different types of adult tissues. This new isolation method overcomes the major shortcomings of conventional methods and is more suitable for producing large numbers of epidermal cells with high potency both for laboratory and for clinical applications. Here, we describe the new method in detail.

Here we present a protocol to efficiently isolate primary human keratinocytes from adult skin tissues. This method simplifies the conventional procedure by using the ROCK Inhibitor Y-27632 in the inoculation medium to spontaneously separate epidermal cells from dermal cells.

Primary human keratinocytes isolated from fresh skin tissues and their expansion in vitro have been widely used for laboratory research and for clinical ...

Hemogenic Reprogramming of Human Fibroblasts by Enforced Expression of Transcription Factors

The cellular and molecular mechanisms underlying specification of human hematopoietic stem cells (HSCs) remain elusive. Strategies to recapitulate human HSC emergence in vitro are required to overcome limitations in studying this complex developmental process. Here, we describe a protocol to generate hematopoietic stem and progenitor-like cells from human dermal fibroblasts employing a direct cell reprogramming approach. These cells transit through a hemogenic intermediate cell-type, resembling the endothelial-to-hematopoietic transition (EHT) characteristic of HSC specification. Fibroblasts were reprogrammed to hemogenic cells via transduction with GATA2, GFI1B and FOS transcription factors. This combination of three factors induced morphological changes, expression of hemogenic and hematopoietic markers and dynamic EHT transcriptional programs. Reprogrammed cells generate hematopoietic progeny and repopulate immunodeficient mice for three months. This protocol can be adapted towards the mechanistic dissection of the human EHT process as exemplified here by defining GATA2 targets during the early phases of reprogramming. Thus, human hemogenic reprogramming provides a simple and tractable approach to identify novel markers and regulators of human HSC emergence. In the future, faithful induction of hemogenic fate in fibroblasts may lead to the generation of patient-specific HSCs for transplantation.

This protocol demonstrates the induction of a hemogenic program in human dermal fibroblasts by enforced expression of the transcription factors GATA2, GFI1B and FOS to generate hematopoietic stem and progenitor cells.

The cellular and molecular mechanisms underlying specification of human hematopoietic stem cells (HSCs) remain elusive. Strategies to recapitulate human ...

Transillumination-Assisted Dissection of Specific Stages of the Mouse Seminiferous Epithelial Cycle for Downstream Immunostaining Analyses

Spermatogenesis is a unique differentiation process that ultimately gives rise to one of the most distinct cell types of the body, the sperm. Differentiation of germ cells takes place in the cytoplasmic pockets of somatic Sertoli cells that host 4 to 5 generations of germ cells simultaneously and coordinate and synchronize their development. Therefore, the composition of germ cell types within a cross-section is constant, and these cell associations are also known as stages (I&#8211;XII) of the seminiferous epithelial cycle. Importantly, stages can also be identified from intact seminiferous tubules based on their differential light absorption/scatter characteristics revealed by transillumination, and the fact that the stages follow each other along the tubule in a numerical order. This article describes a transillumination-assisted microdissection method for the isolation of seminiferous tubule segments representing specific stages of mouse seminiferous epithelial cycle. The light absorption pattern of seminiferous tubules is first inspected under a dissection microscope, and then tubule segments representing specific stages are cut and used for downstream applications. Here we describe immunostaining protocols for stage-specific squash preparations and for intact tubule segments. This method allows a researcher to focus on biological events taking place at specific phases of spermatogenesis, thus providing a unique tool for developmental, toxicological, and cytological studies of spermatogenesis and underlying molecular mechanisms.

This protocol describes transillumination-assisted microdissection of segments of adult mouse seminiferous tubules representing specific stages of seminiferous epithelial cycle, and cell types therein, and subsequent immunostaining of squash preparations and intact tubule segments.