We would like to thank Andrea Portbury for critical reading of the manuscript, the Microscope Service Laboratory of UNC for assistance with the time-lapse imaging, and the NIH (grant # R01HL061656) for funding support.

1. Prepare Antibody-conjugated Beads
<ol>
 <li>One day prior to dissection, combine the antibody of choice with the appropriate Dynabeads (e.g. rat IgG Dynabeads for an antibody raised in rat, 4 x 108 beads/ml) per the manufacturer's instructions. For the BD rat anti-CD31 antibody (0.5 &mu;g/&mu;l, used to isolate endothelial cells), 3 &mu;l antibody is added for every 25 &mu;l beads, for a final concentration of 1.5 &mu;g anti-CD31 antibody and 1 x 107 beads/25 &mu;l buffer.</li>
 <li>Incubate beads and antibody overnight at 4 &deg;C.</li>
</ol>
2. Preparing the Collagen Plate
<ol>
 <li>Isolated cells form tubules more quickly when grown on a collagen gel as opposed to merely a collagen-coated plate. Therefore, collagen gels are made the night before the dissection, as described in 6. On ice in a tissue culture hood, combine the following reagents (enough for 19 wells): 206.4 &mu;l sterile H2O, 140.4 &mu;l collagen type I (4.08 mg/ml), 38.4 &mu;l 10x M199, and 1.15 &mu;l 5 M NaOH.</li>
 <li>Pipette 20 &mu;l of this collagen gel into the wells of a 384-well tissue culture plate. Place the plate in a 37 &deg;C tissue culture incubator for 30 min.</li>
 <li>Add 80 &mu;l DMEM to each well and incubate for 15 min at 37 &deg;C. Remove the culture medium and repeat twice more.</li>
 <li>After the final rinse, add 80 &mu;l 10% FBS/DMEM to each well and incubate overnight at 37 &deg;C. Remove the culture medium prior to adding the isolated cells.</li>
</ol>
3. Excise and Digest the Heart
<ol>
 <li>Euthanize a timed-pregnant mouse at the desired embryonic day using an approved euthanasia technique. All experiments were approved by the Institutional Animal Care and Use Committee at the University of North Carolina at Chapel Hill.</li>
 <li>With the mouse in a supine position, liberally spray the ventral side of the female with 70% ethanol prior to dissection. Using forceps to lift the lower abdominal skin and muscle away from the internal organs, cut open the female's lower abdominal cavity to visualize the internal organs.</li>
 <li>Holding the cervix with forceps, carefully cut caudal to the forceps and begin lifting the uterine horn from the abdominal cavity. While lifting the uterine horn, cut away any connective tissue that holds the horn in place. To finish excising the uterine horn, cut the junction of the uterine horn with the oviduct to free the uterine horn.</li>
 <li>Place the uterine horn in a Petri dish containing cold 1x phosphate-buffered saline (PBS) and rinse as needed. Cut open the uterine horn via the midline to expose the attached embryonic sacs.</li>
 <li>Cut open an embryonic sac at the junction of the placenta and the embryo to avoid accidentally cutting the embryo and retrieve an embryo. Place the embryo in a second Petri dish with cold PBS. Return the Petri dish with the uterine horn to ice.</li>
 <li>Decapitate the embryo to improve access to the chest wall. If genotyping is necessary, cut the tail to remove it and save in an Eppendorf tube placed on ice.</li>
 <li>With the embryo on its back, cut open the chest wall to visualize the heart and lungs. To avoid cutting the heart, make a vertical cut along the side of the rib cage, near a forelimb, followed by a horizontal cut across the bottom of the ribs; then, gently pull the chest wall up and out of the way. Up through approximately embryonic day 13.5, the chest wall is transparent, aiding in visualization.</li>
 <li>Carefully lift the heart using forceps and cut the vessels below. Then, cut above the great vessels to free the heart. If the pulmonary vessels are not cut, the lungs may be removed with the heart. Thus, remove extraneous tissues, like the lungs, if necessary.</li>
 <li>Separate and discard the atria and great vessels from the ventricles. Using scissors, mince the ventricles into small pieces (approximately 1 mm3) and place in approximately 500 &mu;l collagenase (1 mg/ml in sterile PBS). Keep samples on ice until all ventricles have been minced and placed in collagenase.</li>
 <li>Repeat the previous steps until the ventricles have been excised from all embryos, collecting each heart in a separate Eppendorf tube. If all embryos have the same genotype, hearts may be pooled in a single Eppendorf tube. The number of samples processed at a single time may be limited based on the magnet used for isolation; the DynaMag (123-21D) used here holds a maximum of 16 Eppendorf tubes.</li>
 <li>Place the minced ventricles at 37 &deg;C with rocking for 45 min. Every 15 min, gently remove the samples and pipette up and down to mechanically dissociate the cells.</li>
</ol>
4. Isolating the Endothelial Cells
<ol>
 <li>Pass the ventricle-collagenase solution through a 70 &mu;m filter to remove remaining clumps of cells.</li>
 <li>Centrifuge the cells at 400 x g for 10 min. Discard the supernatant, replace with approximately 200 &mu;l 10% FBS in DMEM, and pipette up and down to dissociate the cells.</li>
 <li>Repeat the previous step once. Centrifuge the cells at 400 x g for 10 min after the second 10% FBS/DMEM wash. Resuspend the cells in 50 &mu;l 10% FBS/DMEM.</li>
 <li>During the final centrifugation step, prepare the beads.
 <ol>
 <li>Place the Eppendorf tube containing the antibody and beads on a magnet for 1 min.</li>
 <li>With the tube in place on the magnet, remove the supernatant. Remove the tube from the magnet and add approximately 100 &mu;l 10% FBS/DMEM.</li>
 <li>Place the tube on the magnet for 1 min. Remove the supernatant, and wash again with 10% FBS/DMEM. Repeat for a total of 3 washes.</li>
 <li>After the final wash, resuspend the antibody-conjugated beads in 10% FBS/DMEM (5 &mu;l per sample).</li>
 </ol>
 </li>
 <li>To each cell sample, add 5 &mu;l of the antibody-conjugated beads. Place the bead-cell suspensions at 4 &deg;C with rocking for 30 min.</li>
 <li>In a laminar flow hood, place the Eppendorf tubes containing cells and antibody-conjugated beads on the magnet for 1 min. Remove the supernatant, remove the tubes from the magnet, and wash with approximately 100 &mu;l 10% FBS/DMEM. Repeat for 5 washes.</li>
 <li>After the last wash, place the tubes on the magnet for 1 min, remove the supernatant, and remove the tubes from the magnet. Add approximately 100 &mu;l DMEM.</li>
 <li>Place the tubes on the magnet for 1 min, remove the supernatant, and remove the tubes from the magnet. Add 100-200 &mu;l prewarmed 0.25% trypsin-EDTA. Incubate the samples at 37 &deg;C and 5% CO2 for 5 min.</li>
 <li>Place the tubes on the magnet for 2 min. Carefully transfer the cell-containing supernatant to fresh Eppendorf tubes. Centrifuge for 5 min at 400 x g.</li>
 <li>Remove the supernatant. Resuspend the cells in 80-100 &mu;l growth medium and plate in a 96- or 384-well treated culture dish, depending on the expected yield (approximately 450-600 cells from the ventricles of E14.5-E16.5 embryos). For endothelial cells, use endothelial growth culture medium (defined below).</li>
</ol>

<ol>
	<li>Landecker, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Culturing Life: How Cells Became Technologies. , (2007).</li><li>Kan, C. Y., Wen, V. 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=Endothelial+cell+dysfunction+and+cytoskeletal+changes+associated+with+repression+of+p16(INK4a)+during+immortalization.">Endothelial cell dysfunction and cytoskeletal changes associated with repression of p16(INK4a) during immortalization.</a> Oncogene. , (2012).</li><li>Dyer, L. A., Patterson, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+the+endothelium:+an+emphasis+on+heterogeneity.">Development of the endothelium: an emphasis on heterogeneity.</a> Semin. Thromb. Hemost. 36, 227-235 (2010).</li><li>Dong, Q. G., Bernasconi, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+general+strategy+for+isolation+of+endothelial+cells+from+murine+tissues.+Characterization+of+two+endothelial+cell+lines+from+the+murine+lung+and+subcutaneous+sponge+implants.">A general strategy for isolation of endothelial cells from murine tissues. Characterization of two endothelial cell lines from the murine lung and subcutaneous sponge implants.</a> Arteriosclerosis, Thrombosis, and Vascular Biology. 17, 1599-1604 (1997).</li><li>van Beijnum, J. R., Rousch, M., Castermans, K., vander Linden, E., Griffioen, A. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+endothelial+cells+from+fresh+tissues.">Isolation of endothelial cells from fresh tissues.</a> Nat. Protoc. 3, 1085-1091 (2008).</li><li>Runyan, R. B., Markwald, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Invasion+of+mesenchyme+into+three-dimensional+collagen+gels:+a+regional+and+temporal+analysis+of+interaction+in+embryonic+heart+tissue.">Invasion of mesenchyme into three-dimensional collagen gels: a regional and temporal analysis of interaction in embryonic heart tissue.</a> Dev. Biol. 95, 108-114 (1983).</li><li>Arnaoutova, I., Kleinman, H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+angiogenesis:+endothelial+cell+tube+formation+on+gelled+basement+membrane+extract.">In vitro angiogenesis: endothelial cell tube formation on gelled basement membrane extract.</a> Nat. Protoc. 5, 628-635 (2010).</li><li>Zeisberg, E. M., Potenta, S. E., Sugimoto, H., Zeisberg, M., Kalluri, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fibroblasts+in+kidney+fibrosis+emerge+via+endothelial-to-mesenchymal+transition.">Fibroblasts in kidney fibrosis emerge via endothelial-to-mesenchymal transition.</a> Journal of the American Society of Nephrology : JASN. 19, 2282-2287 (2008).</li><li>Chang, L., Noseda, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differentiation+of+vascular+smooth+muscle+cells+from+local+precursors+during+embryonic+and+adult+arteriogenesis+requires+Notch+signaling.">Differentiation of vascular smooth muscle cells from local precursors during embryonic and adult arteriogenesis requires Notch signaling.</a> PNAS. 109, 5993-6998 (2012).</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> American Journal of Physiology: Lung Cellular and Molecular Physiology. 296, L1095-L1103 (2009).</li><li>Frauli, M., Ludwig, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibition+of+fibroblast+proliferation+in+a+culture+of+human+endometrial+stromal+cells+using+a+medium+containing+D-valine.">Inhibition of fibroblast proliferation in a culture of human endometrial stromal cells using a medium containing D-valine.</a> Archives of Gynecology and Obstetrics. , 241-96 (1987).</li><li>Lazzaro, V. A., Walker, R. 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=Inhibition+of+fibroblast+proliferation+in+L-valine+reduced+selective+media.">Inhibition of fibroblast proliferation in L-valine reduced selective media.</a> Research communications in chemical pathology and pharmacology. 75, 39-48 (1992).</li><li>Arima, S., Nishiyama, K., 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=Angiogenic+morphogenesis+driven+by+dynamic+and+heterogeneous+collective+endothelial+cell+movement.">Angiogenic morphogenesis driven by dynamic and heterogeneous collective endothelial cell movement.</a> Development. 138, 4763-4776 (2011).</li></ol>

The authors declare that they have no competing financial interests.

Working with primary embryonic cells allows novel experiments to address in vitro critical steps of development. However, the isolation procedure is not trivial. Critical steps for isolating any type of cells include ensuring that the cells are well separated upon collagenase digestion and then that they are well suspended during the wash steps. Mechanical dissection by pipetting greatly helps separate the cells during the collagenase step, and the filtering step removes clumps of cells. These steps impro...

The advent of immortalized cell lines has revolutionized basic cell biology 1. The currently available cell lines are derived from a wide range of organs and encompass all the major cell types. However, established cell lines have some limitations. The process of immortalization obviously changes the behavior of the cells, specifically with respect to life span and proliferation, but can also affect the expression of unexpected proteins, such as cytoskeletal proteins 2. In addition, although many different cell lines are available, there is significant diversity among even a single cell type within an entire organism. Endothelial cells in particular show diverse behaviors based on whether they line arteries or veins and what kind of flow is present in the vessel 3. Even more pressing from a developmental perspective, however, is that the vast majority of the available cell lines are derived from adult tissue (see, e.g. the collection available via ATCC). These adult cell lines likely do not recapitulate the dynamic nature of their embryonic precursors. The rapidly changing spatiotemporal gene expression patterns observed during development also suggest that an endothelial cell from one organ at a given developmental stage may not behave the same way as an endothelial cell from that same organ at a different developmental stage.
As an alternative to using commercially available immortalized cell lines, primary cells can be isolated from the specific tissue of interest. Among the advantages of this technique, these primary cells can be isolated from a specific organ or even part of an organ at any specific developmental stage. Further, these primary cells can be isolated from the wide variety of available transgenic animals, allowing the in vitro study of gene knockout and knock-in while avoiding other problems such as transfection efficiency. Not surprisingly, many techniques have been published detailing how to isolate specific cell types 4,5. In general, these techniques involve collecting the region of interest, dissociating the cells, tagging the specific cell type of interest, and isolating those cells for further analysis.
To study an early embryonic population of coronary endothelial cells, we scaled down a previously published technique4 for use with a smaller organ. With this scaled-down procedure, we can isolate the coronary endothelial cells from the embryonic heart at specific embryonic stages. These cells can then be used in traditional endothelial assays, such as migration analyses. Until early embryonic cell lines become more prevalent, working with the primary cells is an invaluable technique.

<table border="1">
		<tbody>
		 <tr>
			<td></td>
			<td></td>
			<td></td>
			<td>REAGENTS</td>
		 </tr>
		 <tr>
			<td>Timed-pregnant mice</td>
			<td></td>
			<td></td>
			<td>To be dissected at the embryonic stage of interest</td>
		 </tr>
		 <tr>
			<td>Anti-mouse CD31</td>
			<td>BD Bioscience</td>
			<td>553370</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Rat IgG Dynabeads</td>
			<td>Invitrogen</td>
			<td>110-35</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Collagen</td>
			<td>BD Bioscience</td>
			<td>354236</td>
			<td></td>
		 </tr>
		 <tr>
			<td>PBS (1x)</td>
			<td></td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>Collagenase, type I</td>
			<td>Worthington Biochemical</td>
			<td>LS004196</td>
			<td></td>
		 </tr>
		 <tr>
			<td>DMEM</td>
			<td>Cellgro </td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>FBS</td>
			<td>Sigma-Aldrich </td>
			<td>F2442 </td>
			<td></td>
		 </tr>
		 <tr>
			<td>Endothelial cell growth medium</td>
			<td>(made in lab as described in notes)</td>
			<td></td>
			<td>DMEM containing 20% FBS, 5 &mu;M &beta;-mercaptoethanol, 50 &mu;g/ml ECG, and 1x penicillin/streptomycin</td>
		 </tr>
		 <tr>
			<td>&beta;-mercaptoethanol</td>
			<td>Sigma-Aldrich</td>
			<td>M6250</td>
			<td></td>
		 </tr>
		 <tr>
			<td>ECGS</td>
			<td>Biomedical Technologies, Inc.</td>
			<td>BT-203</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Penicillin-Streptomycin</td>
			<td>Gibco</td>
			<td>15140</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Trypsin-EDTA</td>
			<td>Gibco</td>
			<td>25300</td>
			<td></td>
		 </tr>
		 <tr>
			<td>384-well culture plate</td>
			<td>Greiner</td>
			<td>T-3037-6</td>
			<td>Plate was prepared with a thin collagen gel, as described in 6; working surface area 10 mm2</td>
		 </tr>
		 <tr>
			<td>Collagen type I</td>
			<td>BD</td>
			<td>354236</td>
			<td>Use at a final concentration of 1.5 mg/ml</td>
		 </tr>
		 <tr>
			<td>M199, 10x</td>
			<td>Invitrogen</td>
			<td>11825-015</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Syto-16</td>
			<td>Invitrogen </td>
			<td>S7578 </td>
			<td>Used as directed in 13 </td>
		 </tr>
		 <tr>
			<td></td>
			<td></td>
			<td></td>
			<td>EQUIPMENT</td>
		 </tr>
		 <tr>
			<td>Stereoscopic microscope</td>
			<td>Nikon </td>
			<td>SMZ645</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Cell culture incubator</td>
			<td>Thermo </td>
			<td>3110 </td>
			<td></td>
		 </tr>
		 <tr>
			<td>DynaMag</td>
			<td>Invitrogen</td>
			<td>123-21D</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Table-top centrifuge</td>
			<td>Thermo</td>
			<td>75002430</td>
			<td></td>
		 </tr>
		</tbody>
 </table>

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.

Using an endothelial-specific antibody that recognizes CD31, endothelial cells were isolated from the ventricles of embryonic (E) 13.5 (Figure 1A) and 18.5 (Figures 1B-1D) embryos. When grown on an untreated culture dish, these cells remain rounded and would form a cobblestone pattern if near confluent (Figure 1A). Dilute collagen has also been used to coat the wells, and while the endothelial cells will adhere to it (Figure 1B), they form fewer chains t...

Watch this Scientific Journal Video about Isolation of Embryonic Ventricular Endothelial Cells at JoVE.com

Isolation of 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-embryonic-ventricular-endothelial-cells

Research

JoVE Journal

Biology

9.3K Views.  University of North Carolina at Chapel Hill. 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.

Video: Isolation of Embryonic Ventricular Endothelial Cells

Isolation of Human Umbilical Vein Endothelial Cells (HUVEC)

Angiogenesis is a complex multi-step process, where in response to angiogenic stimuli, new vessels are created from the existing vasculature. These steps include: degradation of the basement membrane, proliferation and migration (sprouting) of endothelial cells (EC) into the extracellular matrix, alignment of EC into cords, lumen formation, anastomosis, and formation of a new basement membrane. Many in vitro assays have been developed to study this process, but most only mimic certain stages of angiogenesis, and morphologically the vessels often do not resemble vessels in vivo. Here we demonstrate an optimized in vitro angiogenesis assay that utilizes human umbilical vein EC and fibroblasts. This model recapitulates all of the key early stages of angiogenesis, and importantly the vessels display patent intercellular lumens surrounded by polarized EC. Vessels can be easily observed by phase-contrast and time-lapse microscopy, and recovered in pure form for downstream applications.

Isolation of Human Umbilical Vein Endothelial Cells HUVEC

This video protocol illustrates the isolation and culture of human umbilical vein endothelial cells (HUVEC) from human umbilical cord. Once isolated these cells can be used for in vitro angiogenesis assays like the Optimized Fibrin Gel Bead Assay also demonstrated by the Hughes lab.

Angiogenesis is a complex multi-step process, where in response to angiogenic stimuli, new vessels are created from the existing vasculature. These steps ...

Embryonic Stem Cell-Derived Endothelial Cells for Treatment of Hindlimb Ischemia

Peripheral arterial disease (PAD) results from narrowing of the peripheral arteries that supply oxygenated blood and nutrients to the legs and feet, This pathology causes symptoms such as intermittent claudication (pain with walking), painful ischemic ulcerations, or even limb-threatening gangrene. It is generally believed that the vascular endothelium, a monolayer of endothelial cells that invests the luminal surface of all blood and lymphatic vessels, plays a dominant role in vascular homeostasis and vascular regeneration. As a result, stem cell-based regeneration of the endothelium may be a promising approach for treating PAD.In this video, we demonstrate the transplantation of embryonic stem cell (ESC)-derived endothelial cells for treatment of unilateral hindimb ischemia as a model of PAD, followed by non-invasive tracking of cell homing and survival by bioluminescence imaging. The specific materials and procedures for cell delivery and imaging will be described. This protocol follows another publication in describing the induction of hindlimb ischemia by Niiyama et al.1

The surgical procedure for delivery of embryonic stem cell-derived endothelial cells to the ischemic hindlimb is demonstrated, with non-invasive tracking by bioluminescence imaging.

Peripheral arterial disease (PAD) results from narrowing of the peripheral arteries that supply oxygenated blood and nutrients to the legs and feet, This ...

Isolation and Derivation of Mouse Embryonic Germinal Cells

The ability of embryonic germinal cells (EG) to differentiate into primordial germinal cells (PGCs) and later into gametes during early developmental stages is a perfect model to address our hypothesis about cancer and infertility. This protocol shows how to isolate primordial germinal cells from developing gonads in 10.5-11.5 days post coitum (dpc) mouse embryos.  Developing gonadal ridges from mouse embryos (C57BL6J) were dissociated by mechanical disruption with collagenase, then plated in a mouse embryo fibroblast feeder layer (MEF-CF1) that was previously mitotically inactivated with mitomycin C in the presence of knockout media and supplemented with Leukemia Inhibitor Factor (LIF), basic Fibroblast Growth Factor (bFGF), and Stem Cell Factor (SCF).  Using these optimized methods for PCG identification, isolation, and establishment of culture conditions permits long term cultures of EG cells for more than 40 days.  The embryonic germinal cell lines showed embryonic phenotype and expression of common used markers of the pluripotent state.  Isolation and derivation of germinal cells in culture provide a tool to understand their development in vitro and offer the opportunity to monitor cumulative damage at genetic and epigenetic levels after exposure to oxidative stress.

The ability of embryonic germinal cells to differentiate into primordial germinal cells during early development stages is a perfect model to address our hypothesis about cancer and infertility. This protocol shows how to isolate primordial germinal cells from developing gonads in 10.5-11.5 days post coitum mouse embryos.

The ability of embryonic germinal cells (EG) to differentiate into primordial germinal cells (PGCs) and later into gametes during early developmental ...

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 Avian Embryonic Valvular Progenitor Cells

Proper formation and function of embryonic heart valves is critical for developmental progression. The early embryonic heart is a U-shaped tube of endocardium surrounded by myocardium. The myocardium secretes cardiac jelly, a hyaluronan-rich gelatinous matrix, into the atrioventricular (AV) junction and outflow tract (OFT) lumen. At stage HH14 valvulogenesis begins when a subset of endocardial cells receive signals from the myocardium, undergo endocardial to mesenchymal transformation (EMT), and invade the cardiac jelly. At stage HH25 the valvular cushions are fully mesenchymalized, and it is this mesenchyme that eventually forms the valvular and septal apparatus of the heart. Understanding the mechanisms that initiate and modulate the process of EMT and cell differentiation are important because of their connection to serious congenital heart defects. In this study we present methods to isolate pre-EMT endocardial and post-EMT mesenchymal cells, which are the two different cell phenotypes of the prevalvular cushion. Pre-EMT endocardial cells can be cultured with or without the myocardium. Post-EMT AV cushion mesenchymal cells can be cultured inside mechanically constrained or stress-free collagen gels. These 3D in vitro models mimic key valvular morphogenic events and are useful for deconstructing the mechanisms of early and late stage valvulogenesis.

This article will provide a method for isolating and culturing quail or chicken HH14- valve endocardial cells and HH25 valve cushion mesenchymal cells.

Proper formation and function of embryonic heart valves is critical for developmental progression. The early embryonic heart is a U-shaped tube of ...

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 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 ...

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 of High Quality Murine Atrial and Ventricular Myocytes for Simultaneous Measurements of Ca2+ Transients and L-Type Calcium Current

Mouse models play a crucial role in arrhythmia research and allow studying key mechanisms of arrhythmogenesis including altered ion channel function and calcium handling. For this purpose, atrial or ventricular cardiomyocytes of high quality are necessary to perform patch-clamp measurements or to explore calcium handling abnormalities. However, the limited yield of high-quality cardiomyocytes obtained by current isolation protocols does not allow both measurements in the same mouse. This article describes a method to isolate high-quality murine atrial and ventricular myocytes via retrograde enzyme-based Langendorff perfusion, for subsequent simultaneous measurements of calcium transients and L-type calcium current from one animal. Mouse hearts are obtained, and the aorta is rapidly cannulated to remove blood. Hearts are then initially perfused with a calcium-free solution (37 &#176;C) to dissociate the tissue at the level of intercalated discs and afterwards with an enzyme solution containing little calcium to disrupt extracellular matrix (37 &#176;C). The digested heart is subsequently dissected into atria and ventricles. Tissue samples are chopped into small pieces and dissolved by carefully pipetting up and down. The enzymatic digestion is stopped, and cells are stepwise reintroduced to physiologic calcium concentrations. After loading with a fluorescent Ca2+-indicator, isolated cardiomyocytes are prepared for simultaneous measurement of calcium currents and transients. Additionally, isolation pitfalls are discussed and patch-clamp protocols and representative traces of L-type calcium currents with simultaneous calcium transient measurements in atrial and ventricular murine myocytes isolated as described above are provided.

Isolation of High Quality Murine Atrial and Ventricular Myocytes for Simultaneous Measurements of Ca2+ Transients and L-Type Calcium Current

Mouse models allow studying key mechanisms of arrhythmogenesis. For this purpose, high quality cardiomyocytes are necessary to perform patch-clamp measurements. Here, a method to isolate murine atrial and ventricular myocytes via retrograde enzyme-based Langendorff perfusion, which allows simultaneous measurements of calcium-transients and L-type calcium current, is described.

Mouse models play a crucial role in arrhythmia research and allow studying key mechanisms of arrhythmogenesis including altered ion channel function and ...