This work was supported by the NRF grant HUJ-CREATE - Cellular and Molecular Mechanisms of Inflammation.

Mice were housed in pathogen-free conditions in compliance with the institutional guidelines until euthanization (The Institutional Animal Care and Use Committee (IACUC) guidelines at the National University of Singapore and the National Advisory Committee for Laboratory Animal Research (NACLAR) guidelines).
1. Mice
<ol>
	<li>Order one mouse of the appropriate genetic background. This protocol is based on tissue derived from one C57BL/6 mouse.</li>
</ol>
2. Preparation of Complete Medium
<ol>
	<li>Prepare complete medium by adding the following components to Roswell Park Memorial Institute (RPMI) 1640 medium: 10% fetal calf serum (FCS), 50 &#181;M 2-mercaptoethanol, 100 &#181;M asparagine, 2 mM glutamine, 1% penicillin-streptomycin solution.</li>
</ol>
3. Preparation of Enzyme Solutions
<ol>
	<li>Prepare collagenase D solution in a 15 ml conical bottom tube.
	<ol>
		<li>Weigh 10 mg of collagenase D. Dissolve collagenase D in 4 ml complete medium.</li>
	</ol>
	</li>
	<li>Prepare pronase solution in a 1.7 ml microcentrifuge tube.
	<ol>
		<li>Weigh 10 mg of pronase.</li>
		<li>Add 5 &#181;l&#160;of 1 M Tris buffer (pH 8.0). Add 1 &#181;l&#160;of 0.5 M EDTA (pH 8.0).</li>
		<li>Top up with 494 &#181;l&#160;of sterile water.</li>
		<li>Incubate the pronase solution at 37 &#176;C in a water bath for 30 min.</li>
	</ol>
	</li>
</ol>
4. Preparation of Collagenase D-pronase Mix (&#8804;2 Tails)
Note: Perform the subsequent steps in a sterile cell culture hood.
<ol>
	<li>Add 250 &#181;l&#160;of pronase solution to 4 ml of collagenase D solution.</li>
	<li>Pass the collagenase D-pronase mixture through a 0.2 &#181;m syringe filter into a sterile 15 ml conical bottom tube.</li>
</ol>
5. Extraction of Fibroblasts from Ear and Tail Tissues
<ol>
	<li>Euthanize mice according to the appropriate institutional guidelines.</li>
	<li>Place autoclaved surgical instruments (scissors and forceps) in the cell culture hood.</li>
	<li>Add 10 ml complete medium into two 10 cm cell culture dishes each.</li>
	<li>Cut ears (~1 cm radius) and 5 cm of tail (from the tip of the tail) of a mouse with scissors and incubate for 5 min&#160;in 40 ml 70% ethanol in a sterile 50 ml conical bottom tube.</li>
	<li>Air-dry ears and tail by placing them in an open 10 cm cell culture dish in the hood for 5 min. Once dried, transfer ear and tail pieces to two culture dishes labelled &#34;ears&#34; and &#34;tail&#34; containing 10 ml complete medium as described in step 5.3.</li>
	<li>Remove hair from the ears and tail using scissors.</li>
	<li>Cut ears and tail into pieces smaller than 3 mm in size using scissors.</li>
	<li>Transfer the cut tissues into 1.8 ml cryotube vials labelled &#34;ears&#34; and &#34;tail&#34; and add sufficient collagenase D-pronase solution for the volume to reach the 1.8 ml mark on the vial.</li>
	<li>Place the cryotube vials horizontally on a shaker and shake the samples at 200 rpm for 90 min&#160;at 37 &#176;C.</li>
	<li>After 90 min&#160;incubation, remove the cryotube vials from the shaker and place the vials in the hood.</li>
	<li>Add 10 ml complete medium into two 10 cm cell culture dishes, labelled &#34;ears&#34; and &#34;tail&#34; each, and put a 70 &#181;m cell strainer in each dish.</li>
	<li>Place the digested ear and tail tissues in the 70 &#181;m cell strainer in the accordingly labelled dishes prepared in step 5.11 and forcefully grind the tissues using a 10 ml syringe plunger for &#62;5 min. Shake the cell strainer occasionally in the medium to wash cells out of the cell strainer.</li>
	<li>Pipette the cell suspension from each dish into two 15 ml conical bottom tubes labelled &#34;ears&#34; and &#34;tail&#34;. Wash the dish and strainer with additional 10 ml complete medium and add the medium to the appropriate 15 ml conical bottom tubes.</li>
	<li>Spin down the cell suspension for 7 min&#160;at ~580 x g and 4 &#176;C using a refrigerated cell centrifuge.</li>
	<li>Remove supernatant, add 10 ml complete medium to the cell pellet in the 15 ml conical bottom tube and resuspend the cells.</li>
	<li>Repeat step 5.14 and 5.15.</li>
</ol>
6. Culturing of Cell Mixture
<ol>
	<li>Remove supernatant. Ensure that the cell pellet remains undisturbed.</li>
	<li>Re-suspend cells in 10 ml complete medium and add the respective mixture to two 10 cm cell culture dishes labelled &#34;ears&#34; and &#34;tail&#34;.</li>
	<li>Add 10 &#181;l amphotericin B solution (stock solution: 250 &#181;g/ml) to the culture.</li>
	<li>Incubate cells at 37 &#176;C in a humidified 5% CO2 incubator.</li>
	<li>On the third day, replace the medium with 10 ml fresh complete medium containing 10 &#181;l of amphotericin B to remove debris (Figures 1 and 2).</li>
</ol>
7. Sub-culture of Fibroblasts
<ol>
	<li>When culture reaches around 70% confluency (day 3-4 of culture) remove the medium and wash the cells with 5 ml sterile 1x phosphate buffered saline (PBS).</li>
	<li>Remove PBS and add 2 ml sterile 1x trypsin-EDTA solution to the cells.</li>
	<li>Incubate the cells for 5 min&#160;at 37 &#176;C in a humidified 5% CO2 incubator.</li>
	<li>After 5 min, gently tap the culture dish and add 6 ml complete medium to the cells.</li>
	<li>Transfer the cell suspension to a 15 ml conical bottom tube and spin the tube for 5 min&#160;at ~450 x g and 4 &#176;C using a refrigerated cell centrifuge.</li>
	<li>Remove supernatant, and gently re-suspend the cell pellet in 5 ml complete medium.</li>
	<li>Seed 2 x 105 cells in a 10 cm cell culture dish and incubate the cells at 37 &#176;C in a humidified 5% CO2 incubator for 3-4 days before repeating steps 7.1 to 7.6.</li>
</ol>
8. Preparation of Ears for Shipment
Note: Perform the subsequent steps in a sterile cell culture hood.
<ol>
	<li>Euthanize mice according to the appropriate institutional guidelines.</li>
	<li>Place autoclaved scissors and forceps into the cell culture hood.</li>
	<li>Add 50 ml complete medium into a 50 ml conical bottom tube.</li>
	<li>Cut ears (~1 cm radius) of a mouse with scissors.</li>
	<li>Transfer the ears into the 50 ml conical bottom tube (as prepared in step 3) using forceps.</li>
	<li>Seal the 50 ml conical bottom tube with parafilm before shipping at RT in an appropriate box.</li>
</ol>

<ol>
	<li>Fitzpatrick, L. E., McDevitt, T. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell-derived+matrices+for+tissue+engineering+and+regenerative+medicine+applications.">Cell-derived matrices for tissue engineering and regenerative medicine applications.</a> Biomater Sci. 3 (1), 12-24 (2015).</li><li>Elenbaas, B., 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=Human+breast+cancer+cells+generated+by+oncogenic+transformation+of+primary+epithelial+cells.">Human breast cancer cells generated by oncogenic transformation of primary epithelial cells.</a> Genes Dev. 15 (1), 50-65 (2001).</li><li>Stansley, B., Post, J., Hensley, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparative+review+of+cell+culture+systems+for+the+study+of+microglial+biology+in+Alzheimer's+disease.">A comparative review of cell culture systems for the study of microglial biology in Alzheimer's disease.</a> J Neuroinflammation. 9 (1), 115 (2012).</li><li>Lim, J., Dobson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+transfection+of+HUVEC+and+MEF+cells+using+DNA+complexes+with+magnetic+nanoparticles+in+an+oscillating+field.">Improved transfection of HUVEC and MEF cells using DNA complexes with magnetic nanoparticles in an oscillating field.</a> J Genet. 91 (2), 223-227 (2012).</li><li>Li, 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=High-efficiency+transduction+of+fibroblasts+and+mesenchymal+stem+cells+by+tyrosine-mutant+AAV2+vectors+for+their+potential+use+in+cellular+therapy.">High-efficiency transduction of fibroblasts and mesenchymal stem cells by tyrosine-mutant AAV2 vectors for their potential use in cellular therapy.</a> Hum Gene Ther. 21 (11), 1527-1543 (2010).</li><li>Patel, M., Yang, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+reprogramming+somatic+cells+to+induced+pluripotent+stem+cells.">Advances in reprogramming somatic cells to induced pluripotent stem cells.</a> Stem Cell Rev. 6 (3), 367-380 (2010).</li><li>Newman, A. C., Nakatsu, M. N., Chou, W., Gershon, P. D., Hughes, 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=The+requirement+for+fibroblasts+in+angiogenesis:+fibroblast-derived+matrix+proteins+are+essential+for+endothelial+cell+luman+formation.">The requirement for fibroblasts in angiogenesis: fibroblast-derived matrix proteins are essential for endothelial cell luman formation.</a> Mol Biol Cell. 22 (20), 3791-3800 (2011).</li><li>Ohlund, D., Elyada, E., Tuveson, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fibroblast+heterogeneity+in+the+cancer+wound.">Fibroblast heterogeneity in the cancer wound.</a> J Exp Med. 211 (8), 1503-1523 (2014).</li><li>Guo, S., Dipietro, 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=Factors+affecting+wound+healing.">Factors affecting wound healing.</a> J Dent Res. 89 (3), 219-229 (2010).</li><li>Werner, S., Krieg, T., Smola, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Keratinocyte-fibroblast+interactions+in+wound+healing.">Keratinocyte-fibroblast interactions in wound healing.</a> J Invest Dermatol. 127 (5), 998-1008 (2007).</li><li>Shen, Y. 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=Genome-derived+cytosolic+DNA+mediates+type+I+interferon-dependent+rejection+of+B+cell+lymphoma+cells.">Genome-derived cytosolic DNA mediates type I interferon-dependent rejection of B cell lymphoma cells.</a> Cell Rep. 11 (3), 460-473 (2015).</li><li>Seluanov, A., Vaidya, A., Gorbunova, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Establishing+primary+adult+fibroblast+cultures+from+rodents.">Establishing primary adult fibroblast cultures from rodents.</a> J Vis Exp. (44), (2010).</li><li>Baglole, C. 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=Isolation+and+phenotypic+characterization+of+lung+fibroblasts.">Isolation and phenotypic characterization of lung fibroblasts.</a> Methods Mol Med. 117, 115-127 (2005).</li><li>Alt, E., 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=Fibroblasts+share+mesenchymal+phenotypes+with+stem+cells,+but+lack+their+differentiation+and+colony-forming+potential.">Fibroblasts share mesenchymal phenotypes with stem cells, but lack their differentiation and colony-forming potential.</a> Biol Cell. 103 (4), 197-208 (2011).</li><li>Kuilman, T., Michaloglou, C., Mooi, W. J., Peeper, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+essence+of+senescence.">The essence of senescence.</a> Genes Dev. 24 (22), 2463-2479 (2010).</li><li>Lander, M. R., Moll, B., Rowe, W. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+procedure+for+culture+of+cells+from+mouse+tail+biopsies:+brief+communication.">A procedure for culture of cells from mouse tail biopsies: brief communication.</a> J Natl Cancer Inst. 60 (2), 477-478 (1978).</li><li>Moore, C. B., Allen, I. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Primary+ear+fibroblast+derivation+from+mice.">Primary ear fibroblast derivation from mice.</a> Methods Mol Biol. (1031), 65-70 (2013).</li><li>Liu, 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=Generation+of+stable+pluripotent+stem+cells+from+NOD+mouse+tail-tip+fibroblasts.">Generation of stable pluripotent stem cells from NOD mouse tail-tip fibroblasts.</a> Diabetes. 60 (5), 1393-1398 (2011).</li></ol>

The authors declare no conflict of financial interests.

Here we provide a simple, inexpensive and fast experimental procedure to establish primary fibroblast cultures from ears and tails of mice. The extraction should result in adherent and rapidly dividing fibroblasts within 3 days post-isolation of the tissue. An important limitation of primary cells is senescence, a permanent growth arrest15. Using the protocol, fibroblast cultures can be passaged for 5 to 6 times before fibroblasts become senescent, indicated by the flattening of cells, increase in size (2-3 ti...

Primary cells are derived from living tissue and cultured under in vitro conditions. It is generally assumed that primary cells more closely resemble the physiological state and genetic background of the tissue from which they originated than immortalized or tumor cell lines1. For that reason, primary cells represent a useful model for studying biological questions2,3. However, unlike established cell lines that grow indefinitely, primary cells eventually undergo senescence in culture and need to be frequently re-established.
Commonly used primary cells include fibroblasts, epithelial cells, endothelial cells, T cells, B cells, bone marrow-derived macrophages (BMDM) and bone marrow-derived dendritic cells (BMDC). Fibroblasts are often utilized as primary cell culture model. They offer key advantages over other primary cells. Cell cultures are easily established, readily maintained and require no purification of cells prior to culture. They have rapid initial proliferation and no requirement for specialized medium or activation protocols. Fibroblasts can be efficiently transfected using biological, chemical, and physical protocols4,5. There is a possibility to store ears for up to 10 days at RT prior to establishing cell cultures. Fibroblast cultures are conducive to visualization of cytoplasmic processes and suitable for reprogramming into induced pluripotent stem (iPS) cells6.
Fibroblasts are important cells of the connective tissue that secrete collagen proteins and extracellular matrix7. They provide the structural framework in many tissues8 and play an essential role in wound healing and tissue repair9,10.
Here, we describe a simple and quick (&#60;4 hr) protocol to establish fibroblast cultures from ears and tails of mice11. The protocol requires minimal mouse experience to harvest the tissues (in contrast to other protocols12,13) and can be used to establish cultures from ears stored in medium at RT for up to 10 days.

<table border="0" cellpadding="0" cellspacing="0" width="642">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">RPMI-1640</td>
			<td style="width:140px;">HyClone</td>
			<td style="width:119px;">SH30027.01</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Fetal Calf Serum</td>
			<td style="width:140px;">HyClone</td>
			<td style="width:119px;">SV30160.03</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">2-mercaptoethanol</td>
			<td style="width:140px;">Sigma-Aldrich</td>
			<td style="width:119px;">M3148</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Asparagine</td>
			<td style="width:140px;">Sigma-Aldrich</td>
			<td style="width:119px;">A4159</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Glutamine</td>
			<td style="width:140px;">Sigma-Aldrich</td>
			<td style="width:119px;">G8540</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Penicillin/Streptomycin</td>
			<td style="width:140px;">HyClone</td>
			<td style="width:119px;">SV30010</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ethanol</td>
			<td style="width:140px;">Merck Millipore</td>
			<td style="width:119px;">107017</td>
			<td>Absolute for analysis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Collagenase D</td>
			<td style="width:140px;">Roche Diagnostics</td>
			<td style="width:119px;">11088866001</td>
			<td>From Clostridium histolyticum, lyophilized, non-sterile</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Pronase protease</td>
			<td style="width:140px;">Merck Millipore</td>
			<td style="width:119px;">53702</td>
			<td>From Streptomyces griseus&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Tris buffer (pH 8)</td>
			<td style="width:140px;">1st BASE</td>
			<td style="width:119px;">1415</td>
			<td>Ultra pure grade</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">0.5M EDTA (pH 8)</td>
			<td style="width:140px;">1st BASE</td>
			<td style="width:119px;">BUF-1053</td>
			<td>Biotechnology grade</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">10X Phosphate Buffered Saline (PBS)</td>
			<td style="width:140px;">1st BASE</td>
			<td style="width:119px;">BUF-2040-10X4L</td>
			<td>Ultra pure grade</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Trypsin-EDTA solution 10X</td>
			<td style="width:140px;">Sigma-Aldrich</td>
			<td style="width:119px;">59418C-100ML</td>
			<td>0.5% trypsin, 0.2% EDTA, trypsin gamma irradiated by SER-TAIN process, without phenol red, in saline</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Amphotericin B</td>
			<td style="width:140px;">Sigma-Aldrich</td>
			<td style="width:119px;">A2492-20ml</td>
			<td>250 &#956;g/ml in deionized water, sterile-filtered</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Scissors</td>
			<td style="width:140px;">Aesculap</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Forcep</td>
			<td style="width:140px;">Aesculap</td>
			<td style="width:119px;">AE-BD312R</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">0.2 &#956;M syringe filter</td>
			<td style="width:140px;">Sartorius Stedim</td>
			<td style="width:119px;">16534</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">70 &#956;M cell strainer</td>
			<td style="width:140px;">SPL</td>
			<td style="width:119px;">93070</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Syringe plunger</td>
			<td style="width:140px;">Terumo</td>
			<td style="width:119px;">SS+10L</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Cryovial tube</td>
			<td style="width:140px;">NUNC</td>
			<td style="width:119px;">368362</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">1.7 ml microcentrifuge tube</td>
			<td style="width:140px;">Axygen</td>
			<td style="width:119px;">MCT-175-C</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">10 cm cell culture dish</td>
			<td style="width:140px;">Greiner</td>
			<td style="width:119px;">664160</td>
			<td>Cell culture treated dish&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">15 ml conical bottom tube</td>
			<td style="width:140px;">Greiner</td>
			<td style="width:119px;">188271</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">50 ml conical bottom tube</td>
			<td style="width:140px;">Greiner</td>
			<td style="width:119px;">227261</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Water bath</td>
			<td style="width:140px;">GFL</td>
			<td style="width:119px;">1002</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Centrifuge</td>
			<td style="width:140px;">Eppendorf</td>
			<td style="width:119px;">5810R</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Incubation shaker</td>
			<td style="width:140px;">Sartorius Stedim</td>
			<td style="width:119px;"></td>
			<td>Certomat-BS1</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Zeiss Axiovert 25 light microscope</td>
			<td style="width:140px;">Carl Zeiss AG</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

generating primary fibroblast cultures from mouse ear and tail tissues

Primary cells are derived directly from tissue and are thought to be more representative of the physiological state of cells in vivo than established cell lines. However, primary cell cultures usually have a finite life span and need to be frequently re-established. Fibroblasts are an easily accessible source of primary cells. Here, we discuss a simple and quick experimental procedure to establish primary fibroblast cultures from ears and tails of mice. The protocol can be used to establish primary fibroblast cultures from ears stored at RT for up to 10 days. When the protocol is carefully followed, contaminations are unlikely to occur despite the use of non-sterile tissue stored for extended time in some cases. Fibroblasts proliferate rapidly in culture and can be expanded to substantial numbers before undergoing replicative senescence.

Extraction of fibroblasts from tissue results in a significant amount of tissue debris (Figure 1). In contrast to tissue debris, fibroblasts adhere to tissue culture plastic surfaces between day 1 and 3 of culture. The medium of fibroblast cultures can be safely changed on day 3 of culture, which should significantly decrease the levels of debris present in the culture (Figure 2). Fibroblasts display an elongated morphology and a clearly visible cytoplasm (Figures 1 and 2</strong...

Watch this Scientific Journal Video about Generating Primary Fibroblast Cultures from Mouse Ear and Tail Tissues at JoVE.com

Generating Primary Fibroblast Cultures from Mouse Ear and Tail Tissues

We describe a simple and quick experimental procedure for generating primary fibroblasts from the ears and tails of mice. The procedure does not require special animal training and can be used for the generation of fibroblast cultures from ears stored at RT for up to 10 days.

Primary cells are derived directly from tissue and are thought to be more representative of the physiological state of cells in vivo than established cell ...

generating-primary-fibroblast-cultures-from-mouse-ear-and-tail-tissues

Research

JoVE Journal

Developmental Biology

33.6K Views.  Yong Loo Lin School of Medicine, National University of Singapore. We describe a simple and quick experimental procedure for generating primary fibroblasts from the ears and tails of mice. The procedure does not require special animal training and can be used for the generation of fibroblast cultures from ears stored at RT for up to 10 days.

Video: Generating Primary Fibroblast Cultures from Mouse Ear and Tail Tissues

Stable and Efficient Genetic Modification of Cells in the Adult Mouse V-SVZ for the Analysis of Neural Stem Cell Autonomous and Non-autonomous Effects

Relatively quiescent somatic stem cells support life-long cell renewal in most adult tissues. Neural stem cells in the adult mammalian brain are restricted to two specific neurogenic niches: the subgranular zone of the dentate gyrus in the hippocampus and the ventricular-subventricular zone (V-SVZ; also called subependymal zone or SEZ) in the walls of the lateral ventricles. The development of in vivo gene transfer strategies for adult stem cell populations (i.e. those of the mammalian brain) resulting in long-term expression of desired transgenes in the stem cells and their derived progeny is a crucial tool in current biomedical and biotechnological research. Here, a direct in vivo method is presented for the stable genetic modification of adult mouse V-SVZ cells that takes advantage of the cell cycle-independent infection by LVs and the highly specialized cytoarchitecture of the V-SVZ niche. Specifically, the current protocol involves the injection of empty LVs (control) or LVs encoding specific transgene expression cassettes into either the V-SVZ itself, for the in vivo targeting of all types of cells in the niche, or into the lateral ventricle lumen, for the targeting of ependymal cells only. Expression cassettes are then integrated into the genome of the transduced cells and fluorescent proteins, also encoded by the LVs, allow the detection of the transduced cells for the analysis of cell autonomous and non-autonomous, niche-dependent effects in the labeled cells and their progeny.

Here we describe a procedure based on the use of lentiviral particles for the long-term genetic modification of neural stem cells and/or their adjacent ependymal cells in the adult ventricular-subventricular neurogenic niche which allows the separate analysis of cell autonomous and non-autonomous, niche-dependent effects on neural stem cells.

Relatively quiescent somatic stem cells support life-long cell renewal in most adult tissues. Neural stem cells in the adult mammalian brain are ...

Murine Dermal Fibroblast Isolation by FACS

Fibroblasts are the principle cell type responsible for secreting extracellular matrix and are a critical component of many organs and tissues. Fibroblast physiology and pathology underlie a spectrum of clinical entities, including fibroses in multiple organs, hypertrophic scarring following burns, loss of cardiac function following ischemia, and the formation of cancer stroma. However, fibroblasts remain a poorly characterized type of cell, largely due to their inherent heterogeneity. Existing methods for the isolation of fibroblasts require time in cell culture that profoundly influences cell phenotype and behavior. Consequently, many studies investigating fibroblast biology rely upon in vitro manipulation and do not accurately capture fibroblast behavior in vivo. To overcome this problem, we developed a FACS-based protocol for the isolation of fibroblasts from the dorsal skin of adult mice that does not require cell culture, thereby preserving the physiologic transcriptional and proteomic profile of each cell. Our strategy allows for exclusion of non-mesenchymal lineages via a lineage negative gate (Lin-) rather than a positive selection strategy to avoid pre-selection or enrichment of a subpopulation of fibroblasts expressing specific surface markers and be as inclusive as possible across this heterogeneous cell type.

Fibroblast behavior underlies a spectrum of clinical entities, but they remain poorly characterized, largely due to their inherent heterogeneity. Traditional fibroblast research relies upon in vitro manipulation, masking in vivo fibroblast behavior. We describe a FACS-based protocol for the isolation of mouse skin fibroblasts that does not require cell culture.

Fibroblasts are the principle cell type responsible for secreting extracellular matrix and are a critical component of many organs and tissues. Fibroblast ...

Isolation of CD 90+ Fibroblast/Myofibroblasts from Human Frozen Gastrointestinal Specimens

Fibroblasts/myofibroblasts (MFs) have been gaining increasing attention for their role in pathogenesis and their contributions to both wound healing and promotion of the tumor microenvironment. While there are currently many techniques for the isolation of MFs from gastrointestinal (GI) tissues, this protocol introduces a novel element of isolation of these stromal cells from frozen tissue. Freezing GI tissue specimens not only allows the researcher to acquire samples from worldwide collaborators, biobanks, and commercial vendors, it also permits the delayed processing of fresh samples. The described protocol will consistently yield characteristic spindle-shaped cells with the MF phenotype that express the markers CD90, &#945;-SMA and vimentin. As these cells are derived from patient samples, the use of primary cells also confers the benefit of closely mimicking MFs from disease states-namely cancer and inflammatory bowel diseases. This technique has been validated in gastric, small bowel, and colonic MF primary culture generation. Primary MF cultures can be used in a vast array of experiments over a number of passage and their purity assessed by both immunocytochemistry and flow cytometry analysis.

Here, a protocol to isolate and establish primary fibroblast/myofibroblast (MF) cultures from frozen gastric, small intestinal, and colonic tissue-yielding cells with a MF phenotype-is presented. These cells express CD90, &#945;-SMA and vimentin. MFs can be used for a variety of functional assays including enzymatic activity and cytokine production.


Fibroblasts/myofibroblasts (MFs) have been gaining increasing attention for their role in pathogenesis and their contributions to both wound healing and ...

Isolation and Differentiation of Adipose-Derived Stem Cells from Porcine Subcutaneous Adipose Tissues

Obesity is an unconstrained worldwide epidemic. Unraveling molecular controls in adipose tissue development holds promise to treat obesity or diabetes. Although numerous immortalized adipogenic cell lines have been established, adipose-derived stem cells from the stromal vascular fraction of subcutaneous white adipose tissues provide a reliable cellular system ex vivo much closer to adipose development in vivo. Pig adipose-derived stem cells (pADSC) are isolated from 7- to 9-day old piglets. The dorsal white fat depot of porcine subcutaneous adipose tissues is sliced, minced and collagenase digested. These pADSC exhibit strong potential to differentiate into adipocytes. Moreover, the pADSC also possess multipotency, assessed by selective stem cell markers, to differentiate into various mesenchymal cell types including adipocytes, osteocytes, and chondrocytes. These pADSC can be used for clarification of molecular switches in regulating classical adipocyte differentiation or in direction to other mesenchymal cell types of mesodermal origin. Furthermore, extended lineages into cells of ectodermal and endodermal origin have recently been achieved. Therefore, pADSC derived in this protocol provide an abundant and assessable source of adult mesenchymal stem cells with full multipotency for studying adipose development and application to tissue engineering of regenerative medicine.

This protocol describes the isolation of pig adipose-derived stem cells (pADSC) from subcutaneous adipose tissues with examination of multipotency. The multipotent pADSC are used to delineate processes of adipocyte differentiation and study transdifferentiation into multiple cell lineages of mesodermal mesenchyme or further lineages of ectoderm and endoderm for regenerative studies.

Obesity is an unconstrained worldwide epidemic. Unraveling molecular controls in adipose tissue development holds promise to treat obesity or diabetes. ...

Using Primary Neurosphere Cultures to Study Primary Cilia

The primary cilium is fundamentally important for the proliferation of neural stem/progenitor cells and for neuronal differentiation during embryonic, postnatal, and adult life. In addition, most differentiated neurons possess primary cilia that house signaling receptors, such as G-protein-coupled receptors, and signaling molecules, such as adenylyl cyclases. The primary cilium determines the activity of multiple developmental pathways, including the sonic hedgehog pathway during embryonic neuronal development, and also functions in promoting compartmentalized subcellular signaling during adult neuronal function. Unsurprisingly, defects in primary cilium biogenesis and function have been linked to developmental anomalies of the brain, central obesity, and learning and memory deficits. Thus, it is imperative to study primary cilium biogenesis and ciliary trafficking in the context of neural stem/progenitor cells and differentiated neurons. However, culturing methods for primary neurons require considerable expertise and are not amenable to freeze-thaw cycles. In this protocol, we discuss culturing methods for mixed populations of neural stem/progenitor cells using primary neurospheres. The neurosphere-based culturing methods provide the combined benefits of studying primary neural stem/progenitor cells: amenability to multiple passages and freeze-thaw cycles, differentiation potential into neurons/glia, and transfectability. Importantly, we determined that neurosphere-derived neural stem/progenitor cells and differentiated neurons are ciliated in culture and localize signaling molecules relevant to ciliary function in these compartments. Utilizing these cultures, we further describe methods to study ciliogenesis and ciliary trafficking in neural stem/progenitor cells and differentiated neurons. These neurosphere-based methods allow us to study cilia-regulated cellular pathways, including G-protein-coupled receptor and sonic hedgehog signaling, in the context of neural stem/progenitor cells and differentiated neurons.

The primary cilium is fundamentally important in neural progenitor cell proliferation, neuronal differentiation, and adult neuronal function. Here, we describe a method to study ciliogenesis and the trafficking of signaling proteins to cilia in neural stem/progenitor cells and differentiated neurons using primary neurosphere cultures.

The primary cilium is fundamentally important for the proliferation of neural stem/progenitor cells and for neuronal differentiation during embryonic, ...

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. ...

Direct Lineage Reprogramming of Adult Mouse Fibroblast to Erythroid Progenitors

Erythroid cell commitment and differentiation proceed through activation of a lineage-restricted transcriptional network orchestrated by a group of cell fate determining and maturing factors. We previously set out to define the minimal set of factors necessary for instructing red blood cell development using direct lineage reprogramming of fibroblasts into induced erythroid progenitors/precursors (iEPs). We showed that overexpression of Gata1, Tal1, Lmo2, and c-Myc (GTLM) can rapidly convert murine and human fibroblasts directly to iEPs that resemble bona fide erythroid cells in terms of morphology, phenotype, and gene expression. We intend that iEPs will provide an invaluable tool to study erythropoiesis and cell fate regulation. Here we describe the stepwise process of converting murine tail tip fibroblasts into iEPs via transcription factor-driven direct lineage reprogramming (DLR). In this example, we perform the reprogramming in fibroblasts from erythroid lineage-tracing mice that express the yellow fluorescent protein (YFP) under the control of the erythropoietin receptor gene (EpoR) promoter, enabling visualization of erythroid cell fate induction upon reprogramming. Following this protocol, fibroblasts can be reprogrammed into iEPs within five to eight days. 
While improvements can still be made to the process, we show that GTLM-mediated reprogramming is a rapid and direct process, yielding cells with properties of bona fide erythroid progenitor and precursor cells.

Here we present our protocol for producing induced erythroid progenitors (iEPs) from mouse adult fibroblasts using transcription factor-driven direct lineage reprogramming (DLR).

Erythroid cell commitment and differentiation proceed through activation of a lineage-restricted transcriptional network orchestrated by a group of cell ...

Tissue Preparation and Immunostaining of Mouse Craniofacial Tissues and Undecalcified Bone

Tissue immunostaining provides highly specific and reliable detection of proteins of interest within a given tissue. Here we describe a complete and simple protocol to detect protein expression during craniofacial morphogenesis/pathogenesis using mouse craniofacial tissues as examples. The protocol consists of preparation and cryosectioning of tissues, indirect immunofluorescence, image acquisition, and quantification. In addition, a method for preparation and cryosectioning of undecalcified hard tissues for immunostaining is described, using craniofacial tissues and long bones as examples. Those methods are key to determine the protein expression and morphological/anatomical changes in various tissues during craniofacial morphogenesis/pathogenesis. They are also applicable to other tissues with appropriate modifications. Knowledge of the histology and high quality of sections are critical to draw scientific conclusions from experimental outcomes. Potential limitations of this methodology include but are not limited to specificity of antibodies and difficulties of quantification, which are also discussed here.

Here, we present a detailed protocol to detect and quantify protein levels during craniofacial morphogenesis/pathogenesis by immunostaining using mouse craniofacial tissues as examples. In addition, we describe a method for preparation and cryosectioning of undecalcified hard tissues from young mice for immunostaining.

Tissue immunostaining provides highly specific and reliable detection of proteins of interest within a given tissue. Here we describe a complete and ...

Dissection, Culture and Analysis of Primary Cranial Neural Crest Cells from Mouse for the Study of Neural Crest Cell Delamination and Migration

Over the past several decades there has been an increased availability of genetically modified mouse models used to mimic human pathologies. However, the ability to study cell movements and differentiation in vivo is still very difficult. Neurocristopathies, or disorders of the neural crest lineage, are particularly challenging to study due to a lack of accessibility of key embryonic stages and the difficulties in separating out the neural crest mesenchyme from adjacent mesodermal mesenchyme. Here, we set out to establish a well-defined, routine protocol for the culture of primary cranial neural crest cells. In our approach we dissect out the mouse neural plate border during the initial neural crest induction stage. The neural plate border region is explanted and cultured. The neural crest cells form in an epithelial sheet surrounding the neural plate border, and by 24 h after explant, begin to delaminate, undergoing an epithelial-mesenchymal transition (EMT) to become fully motile neural crest cells. Due to our two-dimensional culturing approach, the distinct tissue populations (neural plate versus premigratory and migratory neural crest) can be readily distinguished. Using live imaging approaches, we can then identify changes in neural crest induction, EMT and migratory behaviors. The combination of this technique with genetic mutants will be a very powerful approach for understanding normal and pathological neural crest cell biology.

This protocol describes the dissection and culture of cranial neural crest cells from mouse models, primarily for the study of cell migration. We describe the live imaging techniques used and the analysis of speed and cell shape changes.

Over the past several decades there has been an increased availability of genetically modified mouse models used to mimic human pathologies. However, the ...

Isolation and Differentiation of Primary Myoblasts from Mouse Skeletal Muscle Explants

Primary myoblasts are undifferentiated proliferating precursors of skeletal muscle. They can be cultured and studied as muscle precursors or induced to differentiate into later stages of muscle development. The protocol provided here describes a robust method for the isolation and culture of a highly proliferative population of myoblast cells from young adult mouse skeletal muscle explants. These cells are useful for the study of the metabolic properties of skeletal muscle of different mouse models, as well as in other downstream applications such as transfection with exogenous DNA or transduction with viral expression vectors. The level of differentiation and metabolic profile of these cells depends on the length of exposure, and composition of the media used to induce myoblast differentiation. These methods provide a robust system for the study of mouse muscle cell metabolism ex vivo. Importantly, unlike in vivo models, the methods described here provide a cell population that can be expanded and studied with high levels of reproducibility.

Myoblasts are proliferating precursor cells that differentiate to form polynucleated myotubes and eventually skeletal muscle myofibers. Here, we present a protocol for efficient isolation and culture of primary myoblasts from young adult mouse skeletal muscles. The method enables molecular, genetic, and metabolic studies of muscle cells in culture.

Primary myoblasts are undifferentiated proliferating precursors of skeletal muscle. They can be cultured and studied as muscle precursors or induced to ...