This research was supported in part by American Heart Association grant 0950118G.to M.C-W.

1. Preparing anti-PECAM-1 antibody-conjugated magnetic beads (Dynabeads)
<ol>
<li>Prepare 0.1% BSA in PBS by mixing 50 mg BSA in 50 ml PBS using a vortex until BSA dissolves. Sterilize by filtering through 0.22 &mu;m syringe filter. Store at 4&deg;C.</li>
<li>In the TC hood, transfer 200 &mu;l of well resuspended sheep anti-rat IgG Dynabeads into a 1.5 ml Eppendorf tube and wash the beads: Mount tube on MPC and let sit for about 1 min to allow the beads to sediment. Aspirate supernatant, remove the tube from MPC and resuspend the beads in 1 ml of sterile 0.1% BSA/PBS. Pipette up and down to resuspend beads.</li>
<li>Repeat wash three more times, for a total of four washes.</li>
<li>Remove tube from MPC and resuspend the beads in 500 &mu;l of 0.1% BSA/PBS.</li>
<li>Add 10 &mu;l rat anti-mouse PECAM-1 (CD-31) antibody to the tube.</li>
<li>Tumble overnight at 4&deg;C in the cold room or 2 hrs at room temperature.</li>
<li>Wash the beads with sterile 0.1% BSA/PBS as described in step 1.2 four times.</li>
<li>Remove tube from MPC and resuspend the beads in 200 &mu;l 0.1% BSA/PBS. Store anti-PECAM-1 antibody-conjugated Dynabeads at 4&deg;C for up to 1 month.</li>
</ol>
2. Isolating mouse pulmonary endothelial cells from neonatal mice
Prior to proceeding with the tissue purification protocol, IACUC Committee approval of the procedure is required.
<ol>
<li>Prepare the following:
<ul>
<li>15 ml of 1 mg/ml C/D solution in DMEM. Filter with 0.22 &mu;m syringe filter and warm to 37&deg;C.</li>
<li>50 ml conical tube with 15 ml DMEM, store on ice</li>
<li>Isolation Media (IM) containing 20% FBS and 1x penicillin/streptomycin in DMEM</li>
<li>2% gelatin. Mix 2 g of bovine skin gelatin with 100 ml dd water, autoclave 15 minutes and store at 4&deg;C. Warm to 37&deg;C to liquefy before coating TC flasks.</li>
</ul>
</li>
<li>Anesthetize three 6-8 day old pups using an IP injection of Ketamine (100 mg/kg) and xylazine (10 mg/kg). Check for effectiveness of anesthesia and dissect animals one by one, as follows: Pin pups to board, soak skin with 70% Ethanol and remove skin from the chest area with sterile dissection scissors. Excise the rib cage to expose lungs. </li>
<li>Aseptically excise individual lung lobes, being careful not to dissect the bronchi and any visible connective tissue around the lungs. Combine all lungs in ice-cold DMEM. Euthanize the pups.</li>
<li>Working in the TC hood, remove lung lobes from DMEM, place in a 100 mm TC dish and aspirate excess DMEM.</li>
<li>Using sterile scissors, mince the tissue finely by cutting ~100 times. Transfer to 15 ml warm C/D solution for enzymatic digestion. Incubate 45 minutes at 37&deg;C on a rotator.</li>
<li>In the TC hood, aspirate the digested tissue suspension into to a 20 ml syringe with 14 g cannula attached and triturate clumps into a single cell suspension, at least 12 times.</li>
<li>Pass the tissue suspension through a 70 &mu;m cell strainer and wash the strainer with 15 ml IM to stop digestion.</li>
<li>Pellet cell suspension by centrifugation at 400x g for 5 minutes.</li>
<li>Aspirate supernatant and resuspend pellet in 3 ml 0.1% BSA/PBS.</li>
<li>Transfer cell suspension to 5 ml round-bottom polystyrene tube and add 22.5 &mu;l anti-PECAM-1 antibody-conjugated Dynabeads. Tumble at room temperature for 12 minutes.</li>
<li>Coat a T75 flask with 2 mL 2% gelatin and aspirate excess gelatin. Allow gelatin to dry inside the TC hood for about 30 minutes prior to plating cells.</li>
<li>After bead incubation is complete (step 2.10), split cell suspension equally into three Eppendorf tubes and mount on the MPC.</li>
<li>When the beads have sedimented using the MPC (~1 min), collect supernatant, remove tube from MPC, wash beads with ~1 ml 0.1% BSA/PBS, and then remount on the MPC. </li>
<li>Repeat wash four times (total 5 washes)</li>
<li>Resuspend beads in 1 ml of VascuLife with EnGS-Mv Life Factors Kit and 1x penicillin/streptomycin (VL) per tube, mixing well.</li>
<li>Plate on a pre-coated T75 flask and bring total volume in each flask to 10 ml with VL.</li>
<li>Change media the following day, allow 1 full day of growth, and then change half of the media every other day. When cells are >70-80% confluent or more (usually after 3-4 days of culture), they can be sorted with anti-ICAM-2 Dynabeads.</li>
</ol>
3. Preparing anti-ICAM-2 antibody-conjugated Dynabeads
<ol>
<li>Anti-ICAM-2 antibody-conjugated Dynabeads are used to further purify cells that have been selected with anti-PECAM-1 antibody- conjugated Dynabeads and cultured until confluent. This procedure is performed as described for anti-PECAM-1 antibody-conjugated Dynabeads (1, above), except that anti-mouse ICAM-2 (CD-102) antibody is used instead of anti-PECAM-1 antibody.</li>
<li>Anti-ICAM-2 antibody-conjugated Dynabeads can be stored at 4&deg;C for up to 1 month.</li>
</ol>
4. Sorting Mouse Lung Endothelial Cells with anti-ICAM-2 Dynabeads
<ol>
<li>Coat T75 tissue culture flask with 2% gelatin.</li>
<li>Aspirate the media from the confluent T75 flask with cells and wash with 8 ml PBS. </li>
<li>Aspirate PBS, add 2 ml 0.05% Trypsin/EDTA and let cells detach (about 5 minutes). Tap flasks lightly to aid detaching.</li>
<li>When cells have detached, add 2 ml IM to inhibit trypsin and scrape cells to detach any remaining adherent cells. Transfer cell suspension to a 15 ml tube and spin down for 5 min at 400x g.</li>
<li>Aspirate the media and resuspend cell pellet in 2 ml 0.1%BSA/PBS.</li>
<li>Transfer to a 5 ml polystyrene round-bottom tube and add 10 &mu;l anti-ICAM-2 Dynabeads. Tumble for 12 minutes at RT.</li>
<li>Split cell suspension into two 1.5 ml Eppendorf tubes and mount on MPC.</li>
<li>Aspirate supernatant after beads have adhered for one minute. Remove tubes from MPC and resuspend each tube in 1 ml 0.1% BSA/PBS. Remount on MPC.</li>
<li>Repeat wash four times (total of 5 washes).</li>
<li>Resuspend each tube with 1 ml VL and perform a cell count.</li>
<li>Plate cells at 250-350K cells per T25 flask and/or 750K-1 million cells per T75 flask.</li>
<li>Bring volume to 5 ml VL in T25 flasks, and 10 ml in T75 flasks. </li>
<li>Change media every other day. Cells can be used for experiments when culture reaches about 80% confluency, usually in 2-3 days.</li>
</ol>
5. Representative Results
Typically, after 6-7 days from the initial preparation of the cells, we are able to obtain about 1.2 - 1.5 x 106 pulmonary endothelial cells from three 6-8 day old pups. Cells display typical "cobblestone" morphology under light microscopy and show VE-cadherin (CD144) staining at cell-cell junctions, which is characteristic for endothelial cells (Figure 1). Majority of MLECs express VE-cadherin and VEGFR2 as demonstrated by FACS analysis (Figure 2). Usually, we use them for experiments within two weeks after the initial MLEC isolation.
<img src="/files/ftp_upload/2316/2316fig1.jpg" alt="Figure 1" /> Figure 1. Microscopic analysis of confluent MLEC monolayer. (A) Light microscopy image shows cobblestone morphology of cultured cells typical for endothelial cells. Uniform round structures located in the perinuclear area of many cells are the magnetic beads used for MLEC isolation. (B) Endothelial-specific VE-cadherin is localized at the cell-cell junctions as shown using confocal microscopy. Bar is representative of 20&mu;m.
<img src="/files/ftp_upload/2316/2316fig2.jpg" alt="Figure 2" /> Figure 2. FACS analysis of cultured MLECs labeled with antibodies specific for endothelial-specific markers: VE-cadherin (CD144) or VEGFR2, as indicted, followed by phycoerythrin-conjugated secondary antibody, confirms endothelial identity of isolated MLECs. Red line indicates isotype-specific control, green line indicates anti -VE-cadherin or anti-VEGFR2 - specific-IgG.

<ol>
	<li>Maruyama, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+human+endothelial+cell+in+tissue+culture.">The human endothelial cell in tissue culture.</a> Z Zellforsch Mikrosk. Anat. 60, 69-79 (1963).</li><li>Lim, Y. C., Luscinskas, F. W. <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+murine+heart+and+lung+endothelial+cells+for+in+vitro+model+systems.">Isolation and culture of murine heart and lung endothelial cells for in vitro model systems.</a> Methods Mol Biol. 341, 141-154 (2006).</li><li>Aird, W. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phenotypic+heterogeneity+of+the+endothelium:+I.+Structure,+function,+and+mechanisms.">Phenotypic heterogeneity of the endothelium: I. Structure, function, and mechanisms.</a> Circ Res. 100, 158-173 (2007).</li><li>Fehrenbach, M. L., Cao, G., Williams, J. T., Finklestein, J. M., Delisser, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+murine+lung+endothelial+cells.">Isolation of murine lung endothelial cells.</a> Am J Physiol Lung Cell Mol Physiol. 296, L1096-L1103 (2009).</li><li>Miebach, S., Grau, S., Hummel, V., Rieckmann, P., Tonn, J. C., Goldbrunner, R. 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+culture+of+microvascular+endothelial+cells+from+gliomas+of+different+WHO+grades.">Isolation and culture of microvascular endothelial cells from gliomas of different WHO grades.</a> J. Neurooncol. 76, 39-48 (2006).</li><li>Demeule, M., Labelle, M., R&#233;gina, A., Berthelet, F., B&#233;liveau, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+endothelial+cells+from+brain,+lung,+and+kidney:+expression+of+the+multidrug+resistance+P-glycoprotein+isoforms.">Isolation of endothelial cells from brain, lung, and kidney: expression of the multidrug resistance P-glycoprotein isoforms.</a> Biochem. Biophys. Res. Commun. 281, 827-834 (2001).</li><li>Kajimoto, K., Hossen, N., Hida, K., Ohga, N., Akita, H., Hyodo, M., Hida, Y., Harashima, 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+culture+of+microvascular+endothelial+cells+from+murine+inguinal+and+epididymal+adipose+tissues.">Isolation and culture of microvascular endothelial cells from murine inguinal and epididymal adipose tissues.</a> J. Immunol. Methods. 357, 43-50 (2010).</li><li>Breviario, F., Caveda, L., Corada, M., Martin-Padura, I., Navarro, P., Golay, J., Introna, M., Gulino, D., Lampugnani, M. G., Dejana, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+properties+of+human+vascular+endothelial+cadherin+(7B4/cadherin-5),+an+endothelium-specific+cadherin.">Functional properties of human vascular endothelial cadherin (7B4/cadherin-5), an endothelium-specific cadherin.</a> Arterioscler Thromb Vasc Biol. 15, 1229-1239 (1995).</li><li>Zachary, I., Gliki, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Signaling+transduction+mechanisms+mediating+biological+actions+of+the+vascular+endothelial+growth+factor+family.">Signaling transduction mechanisms mediating biological actions of the vascular endothelial growth factor family.</a> Cardiovasc Res. 49, 568-581 (2001).</li><li>Diglio, C. A., Grammas, P., Giacomelli, F., Wiener, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rat+heart-derived+endothelial+and+smooth+muscle+cell+cultures:+isolation,+cloning+and+characterization.">Rat heart-derived endothelial and smooth muscle cell cultures: isolation, cloning and characterization.</a> Tissue Cell. 20, 477-492 (1988).</li><li>Petzelbauer, P., Bender, J. R., Wilson, J., Pober, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterogeneity+of+dermal+microvascular+endothelial+cell+antigen+expression+and+cytokine+responsiveness+in+situ+and+in+cell+culture.">Heterogeneity of dermal microvascular endothelial cell antigen expression and cytokine responsiveness in situ and in cell culture.</a> J Immunol. 151, 5062-5072 (1993).</li><li>Chrzanowska-Wodnicka, M., Kraus, A. E., Gale, D., White, G. C., Vansluys, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Defective+angiogenesis,+endothelial+migration,+proliferation,+and+MAPK+signaling+in+Rap1b-deficient+mice.">Defective angiogenesis, endothelial migration, proliferation, and MAPK signaling in Rap1b-deficient mice.</a> Blood. 111, 2647-2656 (2008).</li></ol>

Experiments on animals were performed in accordance with the guidelines and regulations set forth by Medical College of Wisconsin IACUC Committee under protocol AUA#00001206.

Microvascular ECs have proven to be a useful model in many areas of vascular biology and are believed to be more physiologically relevant to study (e.g. angiogenesis) than widely studied HUVECs 3. Previously, it has been reported that microvascular ECs can be obtained from kidney, heart, skin, retina, brain, gliomas, adipose tissue and also lung 2, 4-7, 10, 11. However, a consistent and reliable method for isolation of microvascular ECs is still required. The procedure presented here is a modification of a previously published protocol 2; it differs from most published procedures in that it uses pups instead of adult animals. This is crucial for the isolation success as cells from young animals have a higher proliferation potential and cultures derived from their tissues tend to yield higher number of cells. One week old animals seem to be optimal, but younger mice (4 day-old) can also be used. Also, higher or lower numbers of pups can be used if required, as we have been successful in isolating MLECs from one pup. However, while scaling up or down the isolation process, cell plating density must remain unchanged, as this is also critical for cell proliferation. The 2-step purification process of MLECs using magnetic beads conjugated first to anti-PECAM-1 and than anti-ICAM-2 antibodies is much more efficient at obtaining pure EC cultures than the previously described single-step purification procedures. This protocol eliminates the need to use very laborious manual techniques, gradient centrifugation and less efficient FACS sorting for discarding contaminating cells such as fibroblasts, blood cells and smooth muscle cells. The resulting MLEC population can be used for in vitro analysis of angiogenic responses, vascular permeability and leukocyte transmigration, wound healing as well as biochemical analysis of signaling pathways. If required, MLECs can be plated on different surfaces such as fibronectin or gelatin-coated coverslips for immunofluorescence or electrode arrays for trans-endothelial resistance (TER) measurements. Obtained results can be directly compared to the phenotypes observed in vivo, which is especially important in the context of the growing number of knockout and transgenic mouse lines. Successful implementation of this method for in vitro analysis of cellular mechanisms underlying defects observed in vivo, has already been presented 12.

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Spring scissors</td>
<td>&nbsp;</td>
<td>Fine Science Tools</td>
<td>15032-13</td>
<td>&nbsp;</td>
<tr>
<td>forceps</td>
<td>&nbsp;</td>
<td>Fine Science Tools</td>
<td>11223-20</td>
<td>&nbsp;</td>
<tr>
<td>14G cannula</td>
<td>&nbsp;</td>
<td>Fisher</td>
<td>1482516N</td>
<td>&nbsp;</td>
<tr>
<td>20 ml syringe</td>
<td>&nbsp;</td>
<td>BD</td>
<td>309661</td>
<td>&nbsp;</td>
<tr>
<td>BSA</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich </td>
<td>A7030-100G</td>
<td>&nbsp;</td>
<tr>
<td>anti-rat IgG Dynabeads</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>110.35</td>
<td>&nbsp;</td>
<tr>
<td>Magnetic Particle Concentrator (MPC)</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>123-21D</td>
<td>&nbsp;</td>
<tr>
<td>anti-mouse PECAM-1 antibody (CD-31)</td>
<td>&nbsp;</td>
<td>BD Pharmingen</td>
<td>553369</td>
<td>&nbsp;</td>
<tr>
<td>anti-mouse ICAM-2 antibody (CD-102) </td>
<td>&nbsp;</td>
<td>BD Pharmingen</td>
<td>553326</td>
<td>&nbsp;</td>
<tr>
<td>Collagenase/Dispase (C/D)</td>
<td>&nbsp;</td>
<td>Roche Applied Science</td>
<td>11097113001</td>
<td>100mg/ml stock solution can be prepared and stored at -20&deg;C</td>
</tr>
<tr>
<td>DMEM</td>
<td>&nbsp;</td>
<td>Cellgro Mediatech</td>
<td>10-013-CV</td>
<td>&nbsp;</td>
<tr>
<td>Bovine Skin Gelatin</td>
<td>&nbsp;</td>
<td>Sigma-Aldrich</td>
<td>#G9391-100G</td>
<td>&nbsp;</td>
<tr>
<td>Vasculife EnGS-Mv complete kit (VL)</td>
<td>&nbsp;</td>
<td>Lifeline Cell Technology</td>
<td>LL0004</td>
<td>&nbsp;</td>
<tr>
<td>0.05% Trypsin/EDTA </td>
<td>&nbsp;</td>
<td>Mediatech</td>
<td>25-052-CI</td>
<td>&nbsp;</td>
<tr>
<td>Cell strainer 70 &mu;m nylon</td>
<td>&nbsp;</td>
<td>Falcon</td>
<td>352350</td>
<td>&nbsp;</td>
<tr>
<td>tissue culture flask 75 cm2</td>
<td>&nbsp;</td>
<td>TPP</td>
<td>90076</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

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.

Watch this Scientific Journal Video about Isolation and Culture of Pulmonary Endothelial Cells from Neonatal Mice at JoVE.com

Isolation and Culture of Pulmonary Endothelial Cells from Neonatal Mice

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 ...

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46.9K Views.  BloodCenter of Wisconsin. 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.

Video: Isolation and Culture of Pulmonary Endothelial Cells from Neonatal Mice

Isolation of Valvular Endothelial Cells

Heart valves are solely responsible for maintaining unidirectional blood flow through the cardiovascular system. These thin, fibrous tissues are subjected to significant mechanical stresses as they open and close several billion times over a lifespan. The incredible endurance of these tissues is due to the resident valvular endothelial (VEC) and interstitial cells (VIC) that constantly repair and remodel in response to local mechanical and biological signals. Only recently have we begun to understand the unique behaviors of these cells, for which in vitro experimentation has played a key role. Particularly challenging is the isolation and culture of VEC. Special care must be used from the moment the tissue is removed from the host through final plating. Here we present protocols for direct isolation, side specific isolation, culture, and verification of pure populations of VEC. We use enzymatic digestion followed by a gentle swab scraping technique to dislodge only surface cells. These cells are then collected into a tube and centrifuged into a pellet. The pellet is then resuspended and plated into culture flasks pre-coated with collagen I matrix. VEC phenotype is confirmed by contact inhibited growth and the expression of endothelial specific markers such as PECAM1 (CD31), Von Willebrand Factor (vWF), and negative expression of alpha-smooth muscle actin (&alpha;-SMA). The functional characteristics of VEC are associated with high levels of acetylated LDL. Unlike vascular endothelial cells, VEC have the unique capacity to transform into mesenchyme, which normally occurs during embryonic valve formation1. This can also occur during significantly prolonged post confluent in vitro culture, so care should be made to passage at or near confluence. After VEC isolation, pure populations of VIC can then be easily acquired.

We provide a method for isolating and culturing pure populations of heart valve endothelial cells (VEC). VEC can be isolated from either side of the cusp or leaflet and immediately following, underlying interstitial cell (VIC) isolation is straightforward.

Heart valves are solely responsible for maintaining unidirectional blood flow through the cardiovascular system.  These thin, fibrous tissues are ...

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 of Embryonic Ventricular Endothelial Cells

Cell culture has greatly enhanced our ability to assess individual populations of cells under myriad culture conditions. While immortalized cell lines offer significant advantages for their ease of use, these cell lines are unavailable for all potential cell types. By isolating primary cells from a specific region of interest, particularly from a transgenic mouse, more nuanced studies can be performed. The basic technique involves dissecting the organ or partial organ of interest (e.g. the heart or a specific region of the heart) and dissociating the organ to single cells. These cells are then incubated with magnetic beads conjugated to an antibody that recognizes the cell type of interest. The cells of interest can then be isolated with the use of a magnet, with a short trypsin incubation dissociating the cells from the beads. These isolated cells can then be cultured and analyzed as desired. This technique was originally designed for adult mouse organs but can be easily scaled down for use with embryonic organs, as demonstrated herein. Because our interest is in the developing coronary vasculature, we wanted to study this population of cells during specific embryonic stages. Thus, the original protocol had to be modified to be compatible with the small size of the embryonic ventricles and the low potential yield of endothelial cells at these developmental stages. Utilizing this scaled-down approach, we have assessed coronary plexus remodeling in transgenic embryonic ventricular endothelial cells.

Primary cell culture is a useful technique for analyzing specific populations of cells, particularly from transgenic mouse embryos at specific developmental stages. Herein, embryonic ventricles are dissected and dissociated, and antibody-conjugated beads recognize and separate out the endothelial cells for further analysis.

Cell culture has greatly enhanced our ability to assess individual populations of cells under myriad culture conditions. While immortalized cell lines ...

Isolation of Pulmonary Artery Smooth Muscle Cells from Neonatal Mice

Pulmonary hypertension is a significant cause of morbidity and mortality in infants. Historically, there has been significant study of the signaling pathways involved in vascular smooth muscle contraction in PASMC from fetal sheep. While sheep make an excellent model of term pulmonary hypertension, they are very expensive and lack the advantage of genetic manipulation found in mice. Conversely, the inability to isolate PASMC from mice was a significant limitation of that system. Here we described the isolation of primary cultures of mouse PASMC from P7, P14, and P21 mice using a variation of the previously described technique of Marshall et al.26 that was previously used to isolate rat PASMC. These murine PASMC represent a novel tool for the study of signaling pathways in the neonatal period. Briefly, a slurry of 0.5% (w/v) agarose + 0.5% iron particles in M199 media is infused into the pulmonary vascular bed via the right ventricle (RV). The iron particles are 0.2 &#956;M in diameter and cannot pass through the pulmonary capillary bed. Thus, the iron lodges in the small pulmonary arteries (PA). The lungs are inflated with agarose, removed and dissociated. The iron-containing vessels are pulled down with a magnet. After collagenase (80 U/ml) treatment and further dissociation, the vessels are put into a tissue culture dish in M199 media containing 20% fetal bovine serum (FBS), and antibiotics (M199 complete media) to allow cell migration onto the culture dish. This initial plate of cells is a 50-50 mixture of fibroblasts and PASMC. Thus, the pull down procedure is repeated multiple times to achieve a more pure PASMC population and remove any residual iron. Smooth muscle cell identity is confirmed by immunostaining for smooth muscle myosin and desmin.

We have developed a novel and reproducible technique to isolate primary cultures of pulmonary artery smooth muscle cells (PASMC) from mice as young as P7, thereby allowing better study of the signaling pathways involved in neonatal smooth muscle cell contraction and relaxation.

Pulmonary hypertension is a significant cause of morbidity and mortality in infants. Historically, there has been significant study of the signaling ...

Isolation of Murine Valve Endothelial Cells

Normal valve structures consist of stratified layers of specialized extracellular matrix (ECM) interspersed with valve interstitial cells (VICs) and surrounded by a monolayer of valve endothelial cells (VECs). VECs play essential roles in establishing the valve structures during embryonic development, and are important for maintaining life-long valve integrity and function. In contrast to a continuous endothelium over the surface of healthy valve leaflets, VEC disruption is commonly observed in malfunctioning valves and is associated with pathological processes that promote valve disease and dysfunction. Despite the clinical relevance, focused studies determining the contribution of VECs to development and disease processes are limited. The isolation of VECs from animal models would allow for cell-specific experimentation. VECs have been isolated from large animal adult models but due to their small population size, fragileness, and lack of specific markers, no reports of VEC isolations in embryos or adult small animal models have been reported. Here we describe a novel method that allows for the direct isolation of VECs from mice at embryonic and adult stages. Utilizing the Tie2-GFP reporter model that labels all endothelial cells with Green Fluorescent Protein (GFP), we have been successful in isolating GFP-positive (and negative) cells from the semilunar and atrioventricular valve regions using fluorescence activated cell sorting (FACS). Isolated GFP-positive VECs are enriched for endothelial markers, including CD31 and von Willebrand Factor (vWF), and retain endothelial cell expression when cultured; while, GFP-negative cells exhibit molecular profiles and cell shapes consistent with VIC phenotypes. The ability to isolate embryonic and adult murine VECs allows for previously unattainable molecular and functional studies to be carried out on a specific valve cell population, which will greatly improve our understanding of valve development and disease mechanisms.

The ability to isolate heart valve endothelial cells (VECs) is critical for understanding mechanisms of valve development, maintenance, and disease. Here we describe the isolation of VECs from embryonic and adult Tie2-GFP mice using FACS that will allow for studies determining the contribution of VECs in developmental and disease processes.

Normal valve structures consist of stratified layers of specialized extracellular matrix (ECM) interspersed with valve interstitial cells (VICs) and ...

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 ...

Generation and Culture of Blood Outgrowth Endothelial Cells from Human Peripheral Blood

Historically, the limited availability of primary endothelial cells from patients with vascular disorders has hindered the study of the molecular mechanisms underlying endothelial dysfunction in these individuals. However, the recent identification of blood outgrowth endothelial cells (BOECs), generated from circulating endothelial progenitors in adult peripheral blood, may circumvent this limitation by offering an endothelial-like, primary cell surrogate for patient-derived endothelial cells. Beyond their value to understanding endothelial biology and disease modeling, BOECs have potential uses in endothelial cell transplantation therapies. They are also a suitable cellular substrate for the generation of induced pluripotent stem cells (iPSCs) via nuclear reprogramming, offering a number of advantages over other cell types. We describe a method for the reliable generation, culture and characterization of BOECs from adult peripheral blood for use in these and other applications. This approach (i) allows for the generation of patient-specific endothelial cells from a relatively small volume of adult peripheral blood and (ii) produces cells that are highly similar to primary endothelial cells in morphology, cell signaling and gene expression.

This protocol allows for the reliable generation and characterization of blood outgrowth endothelial cells (BOECs) from a small volume of adult peripheral blood. BOECs can be used as a surrogate for endothelial cells from patients with vascular disorders and as a substrate for the generation of induced pluripotent stem cells.

Historically, the limited availability of primary endothelial cells from patients with vascular disorders has hindered the study of the molecular ...

Isolation of Mouse Coronary Endothelial Cells

Endothelial cells line the inner wall of blood vessels and play an important role in the regulation of vascular tone, vascular permeability, and new vascular formation. Endothelial cell dysfunction is implicated in the development and progression of many cardiovascular diseases including ischemic heart disease. To examine the function and characterization of coronary endothelial cells, cell isolation is the first step and it requires high purity and quantity to conduct subsequent experiments. This protocol describes an efficient method to isolate adult mouse coronary endothelial cells. The mouse heart is dissected and minced into small pieces. After the digestion of the heart using dispase and collagenase II, cells are washed&#160;and incubated with magnetic beads which are conjugated with anti-CD31 antibody. The beads with endothelial cells are washed several times and are ready to use in various applications, including imaging and molecular biological experiments. Efficient isolation yields approximately 104 cells per one heart with over 90% purity.

This protocol is prepared to share our method of isolating mouse coronary endothelial cells for the purpose of imaging or to conduct molecular biological experiments.

Endothelial cells line the inner wall of blood vessels and play an important role in the regulation of vascular tone, vascular permeability, and new ...

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.

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 ...