This work was supported by NATIONAL INSTITUTE OF ARTHRITIS AND MUSCULOSKELETAL AND SKIN DISEASES grant (R01AR069653 to Zhang LJ), and National Institutes of Health Support (5T32AR062496-03 to CA).

All animal experiments are approved by the UCSD Institutional Animal Care and Use Committee.
1. Primary Mouse KC Isolation and Culture from Neonatal Skin
<ol>
	<li>Sacrifice the post-natal day 0-2 neonates from the C57B/6 wildtype mouse strain by decapitation using scissors. Cut off the limbs just above the wrist and ankle joints, then cut off the tail completely, leaving a small hole.</li>
	<li>To peel off the whole skin, first insert sharp scissors through the hole at the tail and cut the skin along the dorsal midline of the body to the opening on the neck. Next, use one forceps to grasp the exposed body and the other forceps to grasp the skin, and gently peel the whole skin off the body and over the leg stumps with one continuous motion.
	<ol>
		<li>Peel off the skin as one intact piece and be careful not to break the skin into pieces as this will result in cell loss during the dispase step.</li>
	</ol>
	</li>
	<li>Rinse the peeled skin with 15 mL of sterile PBS in a 10 cm Petri dish, then place the skin from each pup into a 2 mL tube filled with ice cold dispase digestion buffer, which contains 4 mg/mL dispase in KC growth medium (KC basal medium has 0.06 mM CaCl2, dGS, and antibiotics/antimycotics). 
	NOTE: Multiple skin isolates can be combined and incubated in one 15 mL tube (up to 5 skins per tube) containing 12 mL of dispase solution. Incubate the skin tube overnight in a 4 &#176;C refrigerator on a rotator.
	<ol>
		<li>Make sure that the skin is not folded in the tube as this will result in insufficient exposure of the folded region to the dispase solution.</li>
	</ol>
	</li>
	<li>On the next day (after 12-18 h in dispase), transfer the skin together with the dispase solution into a Petri dish. Transfer each tissue piece to a new Petri dish with 15 mL sterile PBS to wash away excess dispase.</li>
	<li>Using two pairs of forceps, grasp the skin from PBS, lift the skin, and transfer to a new Petri dish with the epidermal side down and the dermis side up. Carefully stretch the skin folds so that it is fully extended on the Petri dish.</li>
	<li>Place 500 &#181;L of a trypsin-based digestion solution for each skin in a new Petri dish. Using forceps, slowly lift the dermis up and away from the epidermis, while holding the epidermis down. Dispose the dermis as biohazardous material. Transfer the separated epidermis and float on each drop of trypsin solution with the basal layer downward.
	<ol>
		<li>If the epidermis is folded on the trypsin solution, remove any folds using forceps to ensure efficient digestion of basal KCs from the epithelium.</li>
	</ol>
	</li>
	<li>Incubate the skin on a Petri dish in trypsin solution at room temperature (with the lid covered) on a horizontal shaker with gentle agitation for 20 min.</li>
	<li>Add 2 mL of supplemented KC growth medium per epidermis (about 1 square inch in size per epidermis) to the Petri dish. Grasp the epidermis using forceps, and vigorously rub the epidermis back and forth to release single cells from the epidermal sheet.
	<ol>
		<li>Watch the medium turn increasingly turbid as cells are detached from the epidermis. Tilt the Petri dish to collect and transfer the cell suspension to a new tube leaving the remaining epidermal sheet on the dish.</li>
	</ol>
	</li>
	<li>Repeat two more times the rubbing of the epidermal sheet after adding 2 mL KC growth medium, and combine the cell suspensions in the same tube.</li>
	<li>Pipet the cell solution up-and-down gently a few times to break any cell clumps using the appropriate serological pipette, then pass it through a 100 &#181;m filter to a new 50 mL centrifuge tube.</li>
	<li>Centrifuge the filtered cells for 5 min at 180 x g.</li>
	<li>Aspirate off the supernatant and gently resuspend the cell pellet in 1 mL cold KC growth medium/epidermis.</li>
	<li>Count the cells by a hemocytometer. 
	NOTE: The KCs can spontaneously differentiate in suspension, so the cells should be plated as soon as possible after isolation to ensure the optimal performance of the cells. We recommend placing the cells on ice while counting as this will reduce the rate of KC spontaneous differentiation.</li>
	<li>Seed the cells at a density of 5 x 104/cm2 in KC growth medium in culture dishes pre-coated with an extracellular matrix (ECM) product that promotes cell attachment. 
	NOTE: We use a commercial available (e.g. attachment factor, which is a gelatin-based coating material (see the Table of Materials for details). Cells were cultured in humidified incubator with 5% CO2 at 37 &#176;C, and fresh medium were replenished every other day.
	<ol>
		<li>For coating, coat the culture dishes with the cell attachment coating material warmed to room temperature for 10 min to 2 h prior to the cell seeding. Remove the attachment factor just before adding the cell suspension.</li>
	</ol>
	</li>
	<li>Change the medium 24 h after the initial plating to remove unattached cells, and change the medium daily until the cells reach the desired confluency prior to the experiment.</li>
</ol>
2. Primary Mouse KC Isolation from Adult Tail Skin
<ol>
	<li>Sacrifice an adult C57BL/6 mouse (preferably between 6-15 weeks of age; either male or female) according to the animal facility regulations. Cut off the tail off the body from the tail base, and cut off ~2 mm of the tail tip so that there is a visible hole at the tip.</li>
	<li>To peel the tail skin off, first use a sharp blade to cut along tail skin from the base to the tail tip. Next, use one forceps to grasp the exposed tail bone and the other forceps to grasp the skin, and gently peel the tail skin off the bone with one continuous motion. Cut the peeled skin from the mid-line so that each piece is less than 2-3 cm long.</li>
	<li>Rinse the peeled skin with 15 mL of sterile PBS in a 10 cm Petri dish, then place the skin from each tail into a 2 mL tube filled with ice cold dispase digestion buffer (4 mg/mL dispase in KC growth medium). 
	NOTE: Multiple skin pieces can also be combined and incubated in one 15-mL tube (up to 5 tails per tube) containing 12 mL of dispase solution.
	<ol>
		<li>Incubate the skin tube overnight in a 4 &#176;C refrigerator on a rotator.</li>
	</ol>
	</li>
	<li>Perform steps 1.4 to 1.13 to isolate the single cell suspension from the tail epidermis.</li>
	<li>Seed the adult cells at a density of 10 x 104/cm2 (counted by a hematocytometer) in KC growth medium in culture dishes pre-coated with collagen. 
	NOTE: We use a commercially available collagen-based coating kit (see the Table of Materials for details). Cells were cultured in humidified incubator with 5% CO2 at 37 &#176;C, and fresh medium were replenished every other day. In general, the culture dishes should be coated with collagen for 30 min to 1 h prior to the cell seeding. We observe that there is a significant enhancement of adult KC attachment to the dish when coated with collagen compared to the attachment factor, which is a gelatin-based coating material.</li>
	<li>Change the medium 24 h after the initial plating to remove unattached cells, and change the medium daily until the cells reach the desired confluency prior to the experiment.</li>
</ol>
3. In Vitro Differentiation of KCs by High Calcium
<ol>
	<li>To induce terminal differentiation, add CaCl2 to 0.2 mM in the culture medium.</li>
	<li>Alternatively, starve the cultured KCs overnight without added growth supplements in low calcium KC basal medium prior to the addition of high calcium. 
	NOTE: Growth factor starvation will enhance cell commitment to early differentiation and the induction of early differentiation markers, such as K105.</li>
</ol>
4. UVB Irradiation Mediated Cell Death and TNF&#945; Release from KCs
<ol>
	<li>Culture the mouse KCs in KC growth medium (in humidified incubator with 5% CO2 at 37 &#176;C) with daily medium change until the cells reach confluency. Immediately before the UVB irradiation, remove the growth medium and replace with 500 &#181;L of PBS. Then subject the cells to 25 mJ/cm2 UVB or mock control (no UVB). 
	NOTE: UVB irradiation is performed using handheld UVB lamps with two 8 W bulbs (312 nm) as previously described10. After UVB irradiation, PBS is aspirated and fresh medium is added.</li>
	<li>Measure and quantify the cell viability by the CCK-8 cell viability assay at 6, 8, and 24 h post-UVB treatment following the manufacturer&#39;s instruction11.</li>
	<li>Collect the conditioned medium from the KCs treated with UVB at desired time points and measure the TNF&#945; released in the conditioned medium by the Mouse TNF (Mono/Mono) ELISA kit following the manufacturer&#39;s instruction7,12.</li>
</ol>

<ol>
	<li>Mauro, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Acute+barrier+perturbation+abolishes+the+Ca2++and+K++gradients+in+murine+epidermis:+quantitative+measurement+using+PIXE.">Acute barrier perturbation abolishes the Ca2+ and K+ gradients in murine epidermis: quantitative measurement using PIXE.</a> J Invest Dermatol. 111 (6), 1198-1201 (1998).</li><li>Menon, G. K., Grayson, S., Elias, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ionic+calcium+reservoirs+in+mammalian+epidermis:+ultrastructural+localization+by+ion-capture+cytochemistry.">Ionic calcium reservoirs in mammalian epidermis: ultrastructural localization by ion-capture cytochemistry.</a> J Invest Dermatol. 84 (6), 508-512 (1985).</li><li>Elias, P. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formation+of+the+epidermal+calcium+gradient+coincides+with+key+milestones+of+barrier+ontogenesis+in+the+rodent.">Formation of the epidermal calcium gradient coincides with key milestones of barrier ontogenesis in the rodent.</a> J Invest Dermatol. 110 (4), 399-404 (1998).</li><li>Hennings, H., 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=Calcium+regulation+of+growth+and+differentiation+of+mouse+epidermal+cells+in+culture.">Calcium regulation of growth and differentiation of mouse epidermal cells in culture.</a> Cell. 19 (1), 245-254 (1980).</li><li>Zhang, L. J., Bhattacharya, S., Leid, M., Ganguli-Indra, G., Indra, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ctip2+is+a+dynamic+regulator+of+epidermal+proliferation+and+differentiation+by+integrating+EGFR+and+Notch+signaling.">Ctip2 is a dynamic regulator of epidermal proliferation and differentiation by integrating EGFR and Notch signaling.</a> J Cell Sci. 125 (Pt 23), 5733-5744 (2012).</li><li>Lai, Y. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Commensal+bacteria+regulate+Toll-like+receptor+3-dependent+inflammation+after+skin+injury.">Commensal bacteria regulate Toll-like receptor 3-dependent inflammation after skin injury.</a> Nat Med. 15 (12), 1377-1382 (2009).</li><li>Bernard, J. J., 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=Ultraviolet+radiation+damages+self+noncoding+RNA+and+is+detected+by+TLR3.">Ultraviolet radiation damages self noncoding RNA and is detected by TLR3.</a> Nat Med. 18 (8), (2012).</li><li>Zhang, L. J., 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=Antimicrobial+Peptide+LL37+and+MAVS+Signaling+Drive+Interferon-beta+Production+by+Epidermal+Keratinocytes+during+Skin+Injury.">Antimicrobial Peptide LL37 and MAVS Signaling Drive Interferon-beta Production by Epidermal Keratinocytes during Skin Injury.</a> Immunity. 45 (1), 119-130 (2016).</li><li>Borkowski, A. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toll-Like+Receptor+3+Activation+Is+Required+for+Normal+Skin+Barrier+Repair+Following+UV+Damage.">Toll-Like Receptor 3 Activation Is Required for Normal Skin Barrier Repair Following UV Damage.</a> J Invest Dermatol. 135 (2), 569-578 (2015).</li><li>Borkowski, A. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toll-like+receptor+3+activation+is+required+for+normal+skin+barrier+repair+following+UV+damage.">Toll-like receptor 3 activation is required for normal skin barrier repair following UV damage.</a> J Invest Dermatol. 135 (2), 569-578 (2015).</li><li>Zillessen, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabolic+role+of+dipeptidyl+peptidase+4+(DPP4)+in+primary+human+(pre)adipocytes.">Metabolic role of dipeptidyl peptidase 4 (DPP4) in primary human (pre)adipocytes.</a> Sci Rep. 6, 23074 (2016).</li><li>Wells, C. 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=The+macrophage-inducible+C-type+lectin,+mincle,+is+an+essential+component+of+the+innate+immune+response+to+Candida+albicans.">The macrophage-inducible C-type lectin, mincle, is an essential component of the innate immune response to Candida albicans.</a> J Immunol. 180 (11), 7404-7413 (2008).</li><li>Vasioukhin, V., Bauer, C., Yin, M., Fuchs, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Directed+actin+polymerization+is+the+driving+force+for+epithelial+cell-cell+adhesion.">Directed actin polymerization is the driving force for epithelial cell-cell adhesion.</a> Cell. 100 (2), 209-219 (2000).</li><li>Zhuang, L., 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=TNF+receptor+p55+plays+a+pivotal+role+in+murine+keratinocyte+apoptosis+induced+by+ultraviolet+B+irradiation.">TNF receptor p55 plays a pivotal role in murine keratinocyte apoptosis induced by ultraviolet B irradiation.</a> J Immunol. 162 (3), 1440-1447 (1999).</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> Nat Protoc. 3 (5), 799-810 (2008).</li><li>Dlugosz, A. A., Glick, A. B., Tennenbaum, T., Weinberg, W. C., 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+utilization+of+epidermal+keratinocytes+for+oncogene+research.">Isolation and utilization of epidermal keratinocytes for oncogene research.</a> Methods Enzymol. 254, 3-20 (1995).</li><li>Jones, J. C. <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+culture+of+mouse+keratinocytes.">Isolation and culture of mouse keratinocytes.</a> CSH Protoc. 2008, (2008).</li><li>Pirrone, A., Hager, B., Fleckman, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+mouse+keratinocyte+culture.">Primary mouse keratinocyte culture.</a> Methods Mol Biol. 289, 3-14 (2005).</li><li>Yuspa, S. H., Kilkenny, A. E., Steinert, P. M., Roop, 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=Expression+of+murine+epidermal+differentiation+markers+is+tightly+regulated+by+restricted+extracellular+calcium+concentrations+in+vitro.">Expression of murine epidermal differentiation markers is tightly regulated by restricted extracellular calcium concentrations in vitro.</a> J Cell Biol. 109 (3), 1207-1217 (1989).</li><li>Yuspa, S. H., 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=Signal+transduction+for+proliferation+and+differentiation+in+keratinocytes.">Signal transduction for proliferation and differentiation in keratinocytes.</a> Ann N Y Acad Sci. 548, 191-196 (1988).</li><li>Fang, N. X., 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=Calcium+enhances+mouse+keratinocyte+differentiation+in+vitro+to+differentially+regulate+expression+of+papillomavirus+authentic+and+codon+modified+L1+genes.">Calcium enhances mouse keratinocyte differentiation in vitro to differentially regulate expression of papillomavirus authentic and codon modified L1 genes.</a> Virology. 365 (1), 187-197 (2007).</li><li>Kolly, C., Suter, M. M., Muller, E. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proliferation,+cell+cycle+exit,+and+onset+of+terminal+differentiation+in+cultured+keratinocytes:+pre-programmed+pathways+in+control+of+C-Myc+and+Notch1+prevail+over+extracellular+calcium+signals.">Proliferation, cell cycle exit, and onset of terminal differentiation in cultured keratinocytes: pre-programmed pathways in control of C-Myc and Notch1 prevail over extracellular calcium signals.</a> J Invest Dermatol. 124 (5), 1014-1025 (2005).</li><li>Marcelo, C. L., Gold, R. C., Fairley, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+1.2+mmol/l+calcium,+triamcinolone+acetonide,+and+retinoids+on+low-calcium+regulated+keratinocyte+differentiation.">Effect of 1.2 mmol/l calcium, triamcinolone acetonide, and retinoids on low-calcium regulated keratinocyte differentiation.</a> Br J Dermatol. 111, 64-72 (1984).</li></ol>

The authors have nothing to disclose.

The skin epidermis functions as a critical barrier to separate and protect the body from the outside environment and damage from water loss, pathogens, heat and UV irradiation. The KCs are the predominant cell lineage of the epidermis, and primary culture of epidermal KCs is a useful tool to study and understand the biological processes of barrier formation and the response of KCs to environmental insults in vitro.
Here we describe methods to isolate and culture primary epidermal KCs ...

The skin is the largest organ in the body with the epidermis as the outer most layer. The epidermis plays a critical role in forming an intact epidermal barrier to separate the body from the environment, and thus prevents water loss and provides protection from environmental insults, such as allergens, pathogens and UVB exposure. The epidermis develops from a single layer of undifferentiated basal keratinocytes (KCs) into a multi-layered stratified epithelium consisting of a basal layer, followed by a spinous layer, granular layer, and stratum corneum. Basal KCs, consisting of both epidermal stem cells and transit-amplifying cells, are proliferative and undifferentiated. As basal KCs exit the cell cycle, the cells commit to differentiation and gradually migrate towards the surface of the epidermis, accompanied by the maturation of cell-cell junctions and formation of an epidermal permeability barrier (EPB). The KCs at the spinous layer express early differentiation markers such as Keratin 10 (K10); as the KCs migrate to the granular layer, the cells express late differentiation markers such as Filaggrin (FLG), Loricrin (LOR) and Involucrin (INV). At the stratum corneum, the KCs become terminally differentiated corneocytes, which are eventually shed off through desquamation as new cells replace them.
Calcium is considered the most physiological agent in the epidermis and triggers differentiation in vitro and in vivo in a similar manner. In normal skin epidermis, calcium ions form a characteristic &#34;concentration gradient&#34;, increasing in concentration towards the skin surface1,2,3. The calcium concentration rises from low levels in the lowest sublayers (basal and spinous layers) to a peak in the upper granular layer and then drops to negligible levels in the most superficial layer (stratum corneum). The calcium gradient also develops coincidently with the emergence of a component permeability barrier, which supports that calcium signaling plays a critical role of KC differentiation. In vitro, low calcium (0.02-0.1 mM) maintains the proliferation of basal KCs as a monolayer, whereas high calcium (&#62;0.1 mM) induces a rapid and irreversible commitment of the cells to terminal differentiation as demonstrated by tight-junction formation and induction of LOR and INV upon high calcium treatment to the basal KCs4,5.
In addition to barrier formation, epidermal KCs are also an important component of the skin&#39;s innate immune system. In response to pathogens or damaged-associated molecular patterns (DAMPs) released upon UVB irradiation or injury, KCs can produce large amounts of inflammatory cytokines, such as TNF&#945;, IL6 and IFN&#946;, leading to immune system activation6,7,8,9. Although proper inflammatory signaling from KCs is required for pathogen clearance, uncontrolled inflammatory response may trigger the development of auto-inflammatory skin diseases, such as psoriasis and rosacea6,8.
Overall, KCs play a vital role in maintaining the intact skin barrier and initiating an immune response upon pathogen invasion or environmental insults. Therefore, primary culture of epidermal KCs is a useful technique to study the epithelial biology, KC differentiation, as well as KC-stimulated innate immune responses. The isolation and culture of primary mouse epidermal KCs can be a challenging process due to KC&#39;s susceptibility and sensitivity to various external stimulants. Here we describe a method to isolate and culture KCs from either neonatal mouse skin or adult mouse tail skin. For adult KC isolation, we do not use mouse dorsal skin because isolating sufficient quantities of viable KCs from this tissue can be difficult for the following reasons: First, the adult dorsal skin at the resting phase of the hair cycle (telogen) consists of a thin epidermis with only 1-2 layers of cells, leading to a low cell yield and inefficient separation of the epidermis from the dermis, which is the critical step for successful KC isolation. Second, the high hair follicle density that is present on adult dorsal skin further contributes to the difficulty in separating epidermis from the dermis. Instead, we routinely use tail skin as the source for adult mouse KCs as this epithelium is thicker with 3-5 layers of epidermal KCs. It also has a lower hair follicle density, which does not interfere with the epidermal separation, thus allowing KC isolation from any adult mouse tail skin regardless of the age and hair cycling stage of the mouse. The isolated neonatal KCs are seeded to gelatin-coated culture dishes, whereas collagen-coated dishes are used to seed isolated adult KCs due to the impaired ability of the adult cells to adhere compared to their neonatal counterparts. To culture mouse KCs, low calcium basal medium is supplemented with dGS, which contains epidermal growth factor (EGF), bovine transferrin, insulin-like growth factorc1 (IGF1), prostaglandin E2 (PGE2), bovine serum albumin (BSA) and hydrocortisone. Between 2-4 days after the initial plating, most of the differentiated KCs can be washed away during daily medium changes, and the remaining adherent cells show typical cobblestone morphology4, are proliferating, and do not express the early differentiation marker K10.

<table width="633">
	<tbody>
		<tr height="100">
			<td height="100" style="width:171px;height:100px;">C57BL/6 neonates or adult wildtype mice</td>
			<td style="width:177px;">Jackson Laboratory</td>
			<td style="width:119px;">000664</td>
			<td style="width:167px;">Wildtype mice (originally purchased from Jackson Laboratory) are breeded and maintained in animal vivarium at UCSD.</td>
		</tr>
		<tr height="60">
			<td height="60" style="width:171px;height:60px;">KC basal medium (EpiLife)</td>
			<td style="width:177px;">Invitrogen, Carlsbad, CA</td>
			<td style="width:119px;">MEPICF500</td>
			<td style="width:167px;">basal medium for keratinocyte culture with 0.06 mM CaCl2</td>
		</tr>
		<tr height="60">
			<td height="60" style="width:171px;height:60px;">Defined Growth Supplement (dGS)</td>
			<td style="width:177px;">Invitrogen, Carlsbad, CA</td>
			<td style="width:119px;">S0125</td>
			<td style="width:167px;">defined growth supplements for culture medium</td>
		</tr>
		<tr height="40">
			<td height="40" style="width:171px;height:40px;">Dispase powder</td>
			<td style="width:177px;">Invitrogen, Carlsbad, CA</td>
			<td style="width:119px;">17105041</td>
			<td style="width:167px;">enzyme to dissociate the epidermis from dermis</td>
		</tr>
		<tr height="40">
			<td height="40" style="width:171px;height:40px;">Attachment Factor</td>
			<td style="width:177px;">Invitrogen, Carlsbad, CA</td>
			<td style="width:119px;">S006100</td>
			<td style="width:167px;">gelatin-based coating material</td>
		</tr>
		<tr height="40">
			<td height="40" style="width:171px;height:40px;">Coating Matrix</td>
			<td style="width:177px;">Invitrogen, Carlsbad, CA</td>
			<td style="width:119px;">R011K</td>
			<td style="width:167px;">Collagen-based coating material</td>
		</tr>
		<tr height="80">
			<td height="80" style="width:171px;height:80px;">TrypLE</td>
			<td style="width:177px;">Invitrogen, Carlsbad, CA</td>
			<td style="width:119px;">12604-013</td>
			<td style="width:167px;">A gentle trypsin-like enzyme to dissociate keratinocytes from epidermal sheet</td>
		</tr>
		<tr height="40">
			<td height="40" style="width:171px;height:40px;">100 &#956;m Cell Strainer Nylon mesh</td>
			<td style="width:177px;">Corning</td>
			<td style="width:119px;">352360</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="60">
			<td height="60" style="width:171px;height:60px;">CCK-8 cell viability Kit</td>
			<td style="width:177px;">Dojindo Molecular Technologies, Rockville, MD</td>
			<td style="width:119px;">CK04-11</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="width:171px;height:40px;">Mouse TNF (Mono/Mono) ELISA Set II</td>
			<td style="width:177px;">BD Biosciences, San Jose, CA</td>
			<td style="width:119px;">555268</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="width:171px;height:40px;">Corded Hand-Held UV Lamps</td>
			<td style="width:177px;">Spectronics, Westbury, NY</td>
			<td style="width:119px;">EB-280C</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="width:171px;height:20px;">8-watt UV tubes</td>
			<td style="width:177px;">Spectronics, Westbury, NY</td>
			<td style="width:119px;">BLE-8T312</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="width:171px;height:40px;">Light Inverted Microscope for cell culture</td>
			<td style="width:177px;">ZEISS, Jena, Germany</td>
			<td style="width:119px;">Axio Observer</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="width:171px;height:20px;">Fluorescent Microscope</td>
			<td style="width:177px;">Olympus</td>
			<td style="width:119px;">BX41</td>
			<td style="width:167px;"></td>
		</tr>
	</tbody>
</table>

isolation and culture of primary mouse keratinocytes from neonatal and adult mouse skin

The keratinocyte (KC) is the predominant cell type in the epidermis, the outermost layer of the skin. Epidermal KCs play a critical role in providing skin defense by forming an intact skin barrier against environmental insults, such as UVB irradiation or pathogens, and also by initiating an inflammatory response upon those insults. Here we describe methods to isolate KCs from neonatal mouse skin and from adult mouse tail skin. We also describe culturing conditions using defined growth supplements (dGS) in comparison to chelexed fetal bovine serum (cFBS). Functionally, we show that both neonatal and adult KCs are highly responsive to high calcium-induced terminal differentiation, tight junction formation and stratification. Additionally, cultured adult KCs are susceptible to UVB-triggered cell death and can release large amounts of TNF upon UVB irradiation. Together, the methods described here will be useful to researchers for the setup of in vitro models to study epidermal biology in the neonatal mouse and/or the adult mouse.

High calcium induced terminal differentiation of neonatal and adult KCs. The primary mouse epidermal KCs plated and maintained at 0.06 mM CaCl2 grew as a monolayer, and individual cells had a polygonal shape with distinct intercellular space, showing a cobblestone appearance when confluent (Figure 1A and Figure 2A). Elevating the CaCl2 to 0.2 mM induced a rapid morphology change of the cells...

Watch this Scientific Journal Video about Isolation and Culture of Primary Mouse Keratinocytes from Neonatal and Adult Mouse Skin at JoVE.com

Isolation and Culture of Primary Mouse Keratinocytes from Neonatal and Adult Mouse Skin

Epidermal keratinocytes form a functional skin barrier and are positioned at the front line of host defense against external environmental insults. Here we describe methods for isolation and primary culture of epidermal keratinocytes from neonatal and adult mouse skin, and induction of terminal differentiation and UVB-triggered inflammatory response from keratinocytes.

The keratinocyte (KC) is the predominant cell type in the epidermis, the outermost layer of the skin. Epidermal KCs play a critical role in providing skin ...

isolation-culture-primary-mouse-keratinocytes-from-neonatal-adult

Research

JoVE Journal

Biology

30.5K Views.  UC San Diego. Epidermal keratinocytes form a functional skin barrier and are positioned at the front line of host defense against external environmental insults. Here we describe methods for isolation and primary culture of epidermal keratinocytes from neonatal and adult mouse skin, and induction of terminal differentiation and UVB-triggered inflammatory response from keratinocytes.

Video: Isolation and Culture of Primary Mouse Keratinocytes from Neonatal and Adult Mouse Skin

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

Isolation and Culture of Pulmonary Endothelial Cells from Neonatal Mice

Endothelial cells provide a useful research model in many areas of vascular biology. Since its first isolation 1, human umbilical vein endothelial cells (HUVECs) have shown to be convenient, easy to obtain and culture, and thus are the most widely studied endothelial cells. However, for research focused on processes like angiogenesis, permeability or many others, microvascular endothelial cells (ECs) are a much more physiologically relevant model to study 2. Furthermore, ECs isolated from knockout mice provide a useful tool for analysis of protein function ex vivo. Several approaches to isolate and culture microvascular ECs of different origin have been reported to date 3-7, but consistent isolation and culture of pure ECs is still a major technical problem in many laboratories. Here, we provide a step-by-step protocol on a reliable and relatively simple method of isolating and culturing mouse lung endothelial cells (MLECs). In this approach, lung tissue obtained from 6- to 8-day old pups is first cut into pieces, digested with collagenase/dispase (C/D) solution and dispersed mechanically into single-cell suspension. MLECS are purified from cell suspension using positive selection with anti-PECAM-1 antibody conjugated to Dynabeads using a Magnetic Particle Concentrator (MPC). Such purified cells are cultured on gelatin-coated tissue culture (TC) dishes until they become confluent. At that point, cells are further purified using Dynabeads coupled to anti-ICAM-2 antibody. MLECs obtained with this protocol exhibit a cobblestone phenotype, as visualized by phase-contrast light microscopy, and their endothelial phenotype has been confirmed using FACS analysis with anti-VE-cadherin 8 and anti-VEGFR2 9 antibodies and immunofluorescent staining of VE-cadherin. In our hands, this two-step isolation procedure consistently and reliably yields a pure population of MLECs, which can be further cultured. This method will enable researchers to take advantage of the growing number of knockout and transgenic mice to directly correlate in vivo studies with results of in vitro experiments performed on isolated MLECs and thus help to reveal molecular mechanisms of vascular phenotypes observed in vivo.

Here, we describe a protocol for isolation and culture of murine pulmonary endothelial cells. This method comprises mechanic and enzymatic lung tissue dissociation as well as a 2-step purification process using anti-PECAM-1 and anti-ICAM-2 antibodies conjugated to magnetic beads, which produces a pure endothelial cell population of mostly microvascular origin.

Endothelial cells provide a useful research model in many areas of vascular biology. Since its first isolation 1, human umbilical vein endothelial cells ...

Isolation and Culture of Adult Epithelial Stem Cells from Human Skin

The homeostasis of all self-renewing tissues is dependent on adult stem cells. As undifferentiated stem cells undergo asymmetric divisions, they generate daughter cells that retain the stem cell phenotype and transit-amplifying cells (TA cells) that migrate from the stem cell niche, undergo rapid proliferation and terminally differentiate to repopulate the tissue.
Epithelial stem cells have been identified in the epidermis, hair follicle, and intestine as cells with a high in vitro proliferative potential and as slow-cycling label-retaining cells in vivo 1-3. Adult, tissue-specific stem cells are responsible for the regeneration of the tissues in which they reside during normal physiologic turnover as well as during times of stress 4-5. Moreover, stem cells are generally considered to be multi-potent, possessing the capacity to give rise to multiple cell types within the tissue 6. For example, rodent hair follicle stem cells can generate epidermis, sebaceous glands, and hair follicles 7-9. We have shown that stem cells from the human hair follicle bulge region exhibit multi-potentiality 10.
Stem cells have become a valuable tool in biomedical research, due to their utility as an in vitro system for studying developmental biology, differentiation, tumorigenesis and for their possible therapeutic utility. It is likely that adult epithelial stem cells will be useful in the treatment of diseases such as ectodermal dysplasias, monilethrix, Netherton syndrome, Menkes disease, hereditary epidermolysis bullosa and alopecias 11-13. Additionally, other skin problems such as burn wounds, chronic wounds and ulcers will benefit from stem cell related therapies 14,15. Given the potential for reprogramming of adult cells into a pluripotent state (iPS cells)16,17, the readily accessible and expandable adult stem cells in human skin may provide a valuable source of cells for induction and downstream therapy for a wide range of disease including diabetes and Parkinson's disease.

A rapid, robust way of isolating viable adult epithelial stem cells from human skin is described. The method utilizes enzymatic digestion of skin collagen matrix , followed by plucking of hair follicles and isolation of single cell suspensions or tissue fragments for cell culture.

The homeostasis of all self-renewing tissues is dependent on adult stem cells. As undifferentiated stem cells undergo asymmetric divisions, they generate ...

Isolation and Culture of Neonatal Mouse Cardiomyocytes

Cultured neonatal cardiomyocytes have long been used to study myofibrillogenesis and myofibrillar functions. Cultured cardiomyocytes allow for easy investigation and manipulation of biochemical pathways, and their effect on the biomechanical properties of spontaneously beating cardiomyocytes.	
The following 2-day protocol describes the isolation and culture of neonatal mouse cardiomyocytes. We show how to easily dissect hearts from neonates, dissociate the cardiac tissue and enrich cardiomyocytes from the cardiac cell-population. We discuss the usage of different enzyme mixes for cell-dissociation, and their effects on cell-viability. The isolated cardiomyocytes can be subsequently used for a variety of morphological, electrophysiological, biochemical, cell-biological or biomechanical assays. We optimized the protocol for robustness and reproducibility, by using only commercially available solutions and enzyme mixes that show little lot-to-lot variability. We also address common problems associated with the isolation and culture of cardiomyocytes, and offer a variety of options for the optimization of isolation and culture conditions.

Primary mouse cardiomyocyte cultures are one of the pivotal tools for the investigation of myofibrillar organization and function. The following protocol describes the isolation and culture of primary cardiomyocytes from neonatal mouse hearts. The resulting cardiomyocyte cultures may be subsequently used for a variety of biomechanical, biochemical and cell-biological assays.

Cultured neonatal cardiomyocytes have long been used to study  myofibrillogenesis and myofibrillar functions. Cultured cardiomyocytes allow  for easy ...

Isolation, Culture, and Functional Characterization of Adult Mouse Cardiomyoctyes

The use of primary cardiomyocytes (CMs) in culture has provided a powerful complement to murine models of heart disease in advancing our understanding of heart disease. In particular, the ability to study ion homeostasis, ion channel function, cellular excitability and excitation-contraction coupling and their alterations in diseased conditions and by disease-causing mutations have led to significant insights into cardiac diseases. Furthermore, the lack of an adequate immortalized cell line to mimic adult CMs, and the limitations of neonatal CMs (which lack many of the structural and functional biomechanics characteristic of adult CMs) in culture have hampered our understanding of the complex interplay between signaling pathways, ion channels and contractile properties in the adult heart strengthening the importance of studying adult isolated cardiomyocytes. Here, we present methods for the isolation, culture, manipulation of gene expression by adenoviral-expressed proteins, and subsequent functional analysis of cardiomyocytes from the adult mouse. The use of these techniques will help to develop mechanistic insight into signaling pathways that regulate cellular excitability, Ca2+ dynamics and contractility and provide a much more physiologically relevant characterization of cardiovascular disease.

Here we describe the isolation of adult mouse cardiomyoctyes using a Langendorff perfusion system. The resulting cells are Ca2+-tolerant, electrically quiescent and can be cultured and transfected with adeno- or lentiviruses to manipulate gene expression. Their functionality can also be analyzed using the MMSYS system and patch clamp techniques.

The use of primary cardiomyocytes (CMs) in culture has provided a powerful complement to murine models of heart disease in advancing our understanding of ...

Isolation and Culture of Mouse Primary Pancreatic Acinar Cells

This protocol permits rapid isolation (in less than 1 hr) of murine pancreatic acini, making it possible to maintain them in culture for more than one week. More than 20 x 106 acinar cells can be obtained from a single murine pancreas. This protocol offers the possibility to independently process as many as 10 pancreases in parallel. Because it preserves acinar architecture, this model is well suited for studying the physiology of the exocrine pancreas in vitro in contrast to cell lines established from pancreatic tumors, which display many genetic alterations resulting in partial or total loss of their acinar differentiation.

In this publication, we describe a rapid and convenient procedure for isolating and culturing primary pancreatic acinar cells from the murine pancreas. This method constitutes a valuable approach to study the physiology of fresh primary normal/untransformed exocrine pancreatic cells.

This protocol permits rapid isolation (in less than 1 hr) of murine pancreatic acini, making it possible to maintain them in culture for more than one ...

Isolation of Primary Myofibroblasts from Mouse and Human Colon Tissue

The myofibroblast is a stromal cell of the gastrointestinal (GI) tract that has been gaining considerable attention for its critical role in many GI functions. While several myofibroblast cell lines are commercially available to study these cells in vitro, research results from a cell line exposed to experimental cell culture conditions have inherent limitations due to the overly reductionist nature of the work. Use of primary myofibroblasts offers a great advantage in terms of confirming experimental findings identified in a cell line. Isolation of primary myofibroblasts from an animal model allows for the study of myofibroblasts under conditions that more closely mimic the disease state being studied. Isolation of primary myofibroblasts from human colon tissue provides arguably the most relevant experimental data, since the cells come directly from patients with the underlying disease. We describe a well-established technique that can be utilized to isolate primary myofibroblasts from both mouse and human colon tissue. These isolated cells have been characterized to be alpha-smooth muscle actin and vimentin-positive, and desmin-negative, consistent with subepithelial intestinal myofibroblasts. Primary myofibroblast cells can be grown in cell culture and used for experimental purposes over a limited number of passages.

The myofibroblast is an influential stromal cell of the gastrointestinal tract that regulates important physiologic processes in both normal and disease states. We describe a technique that allows for the isolation of primary myofibroblasts from both mouse and human colon tissue, which can be utilized for in vitro experimentation.

The myofibroblast is  a stromal cell of the gastrointestinal (GI) tract that has been gaining  considerable attention for its critical role in many GI ...

Isolation and Culture of Dental Epithelial Stem Cells from the Adult Mouse Incisor

Understanding the cellular and molecular mechanisms that underlie tooth regeneration and renewal has become a topic of great interest1-4, and the mouse incisor provides a model for these processes. This remarkable organ grows continuously throughout the animal&#39;s life and generates all the necessary cell types from active pools of adult stem cells housed in the labial (toward the lip) and lingual (toward the tongue) cervical loop (CL) regions. Only the dental stem cells from the labial CL give rise to ameloblasts that generate enamel, the outer covering of teeth, on the labial surface. This asymmetric enamel formation allows abrasion at the incisor tip, and progenitors and stem cells in the proximal incisor ensure that the dental tissues are constantly replenished. The ability to isolate and grow these progenitor or stem cells in vitro allows their expansion and opens doors to numerous experiments not achievable in vivo, such as high throughput testing of potential stem cell regulatory factors. Here, we describe and demonstrate a reliable and consistent method to culture cells from the labial CL of the mouse incisor.

The continuously growing mouse incisor provides a model for studying renewal of dental tissues from dental epithelial stem cells (DESCs). A robust system for consistently and reliably obtaining these cells from the incisor and expanding them in vitro is reported here.

Understanding the cellular and molecular mechanisms that underlie tooth regeneration and renewal has become a topic of great interest1-4, and the mouse ...

Isolation and Primary Culture of Mouse Aortic Endothelial Cells

The vascular endothelium is essential to normal vascular homeostasis. Its dysfunction participates in various cardiovascular disorders. The mouse is an important model for cardiovascular disease research. This study demonstrates a simple method to isolate and culture endothelial cells from the mouse aorta without any special equipment. To isolate endothelial cells, the thoracic aorta is quickly removed from the mouse body, and the attached adipose tissue and connective tissue are removed from the aorta. The aorta is cut into 1 mm rings. Each aortic ring is opened and seeded onto a growth factor reduced matrix with the endothelium facing down. The segments are cultured in endothelial cell growth medium for about 4 days. The endothelial sprouting starts as early as day 2. The segments are then removed and the cells are cultured continually until they reach confluence. The endothelial cells are harvested using neutral proteinase and cultured in endothelial cell growth medium for another two passages before being used for experiments. Immunofluorescence staining indicated that after the second passage the majority of cells were double positive for Dil-ac-LDL uptake, Lectin binding, and CD31 staining, the typical characteristics of endothelial cells. It is suggested that cells at the second to third passages are suitable for in vitro and in vivo experiments to study the endothelial biology. Our protocol provides an effective means of identifying specific cellular and molecular mechanisms in endothelial cell physiopathology.

The vascular endothelial cells play a significant role in many important cardiovascular disorders. This article describes a simple method to isolate and expand endothelial cells from the mouse aorta without using any special equipment. Our protocol provides an effective means of identifying mechanisms in endothelial cell physiopathology.

The vascular endothelium is essential to normal vascular homeostasis. Its dysfunction participates in various cardiovascular disorders. The mouse is an ...

Isolation, Culture and Transduction of Adult Mouse Cardiomyocytes

Cultured cardiomyocytes can be used to study cardiomyocyte biology using techniques that are complementary to in vivo systems. For example, the purity and accessibility of in vitro culture enables fine control over biochemical analyses, live imaging, and electrophysiology. Long-term culture of cardiomyocytes offers access to additional experimental approaches that cannot be completed in short term cultures. For example, the in vitro investigation of dedifferentiation, cell cycle re-entry, and cell division has thus far largely been restricted to rat cardiomyocytes, which appear to be more robust in long-term culture. However, the availability of a rich toolset of transgenic mouse lines and well-developed disease models make mouse systems attractive for cardiac research. Although several reports exist of adult mouse cardiomyocyte isolation, few studies demonstrate their long-term culture. Presented here, is a step-by-step method for the isolation and long-term culture of adult mouse cardiomyocytes. First, retrograde Langendorff perfusion is used to efficiently digest the heart with proteases, followed by gravity sedimentation purification. After a period of dedifferentiation following isolation, the cells gradually attach to the culture and can be cultured for weeks. Adenovirus cell lysate is used to efficiently transduce the isolated cardiomyocytes. These methods provide a simple, yet powerful model system to study cardiac biology.

This protocol describes a step-by-step method for the reproducible isolation and long-term culture of adult mouse cardiomyocytes with high yield, purity, and viability.

Cultured cardiomyocytes can be used to study cardiomyocyte biology using techniques that are complementary to in vivo systems. For example, the purity and ...

Isolation and Culture of Primary Mouse Keratinocytes from Neonatal and Adult Mouse Skin

Podsumowanie

Przeglądaj więcej filmów

Rozdziały w tym wideo

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Isolation and Culture of Pulmonary Endothelial Cells from Neonatal Mice

Isolation and Culture of Adult Epithelial Stem Cells from Human Skin

Isolation and Culture of Neonatal Mouse Cardiomyocytes

Isolation, Culture, and Functional Characterization of Adult Mouse Cardiomyoctyes

Isolation and Culture of Mouse Primary Pancreatic Acinar Cells

Isolation of Primary Myofibroblasts from Mouse and Human Colon Tissue

Isolation and Culture of Dental Epithelial Stem Cells from the Adult Mouse Incisor

Isolation and Primary Culture of Mouse Aortic Endothelial Cells

Isolation, Culture and Transduction of Adult Mouse Cardiomyocytes