Name: methods for the isolation, culture, and functional characterization of sinoatrial node myocytes from adult mice
Uploaded: 2016-10-23T14:00:00
Description: Watch this Scientific Journal Video about Methods for the Isolation, Culture, and Functional Characterization of Sinoatrial Node Myocytes from Adult Mice at JoVE.com

We thank Dr. Christian Rickert for critical reading of the manuscript. This work was supported by a grant from the National Heart Lung and Blood Institute (R01-HL088427) to CP. EJS was supported by 5T32-AG000279 from the National Institute on Aging. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

All animal procedures were performed in accordance with protocols approved by the Institutional Animal Care and Use Committee of the University of Colorado Anschutz Medical Campus. The standard protocol below has been optimized using male C57BL/6J mice of 2-3 months of age.
1. Prepare Solution Stocks and Supplies in Advance of Experiments
NOTE: Refer to Materials Table for necessary equipment and supplies.
<ol>
	<li>Prepare 1 L each of the followi...

<ol>
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D., 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=Complete+atrial-specific+knockout+of+sodium-calcium+exchange+eliminates+sinoatrial+node+pacemaker+activity.">Complete atrial-specific knockout of sodium-calcium exchange eliminates sinoatrial node pacemaker activity.</a> PloS ONE. 8 (11), e81633 (2013).</li><li>Torrente, A. G., Zhang, R., 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=Burst+pacemaker+activity+of+the+sinoatrial+node+in+sodium-calcium+exchanger+knockout+mice.">Burst pacemaker activity of the sinoatrial node in sodium-calcium exchanger knockout mice.</a> Proc Nat Acad Sci USA. 112 (31), 9769-9774 (2015).</li><li>Denyer, J. C., Brown, H. 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This paper presents detailed protocols for the isolation and culture of fully differentiated sinoatrial node myocytes from adult mice. The isolation protocol reliably produces spontaneously active mouse SAMs suitable for either immediate electrophysiological analysis or subsequent culture. Similar protocols have been reported by many other groups (for example, see references11,12,10,13-17). However, our protocol for maintaining adult mouse SAMs in vitro preserves the characteristic morphology, spontan...

Pacemaker myocytes in the sinoatrial node of the heart (sinoatrial myocytes, &#34;SAMs&#34;) generate spontaneous, rhythmic action potentials (APs) that propagate through the myocardium to initiate each heartbeat. Experiments using acutely isolated SAMs from many species have been essential for elucidation of mechanisms that contribute to the generation of pacemaker activity. SAMs are highly specialized cardiomyocytes that differ substantially from their counterparts in the atrial and ventricular myocardium in terms of morphology, function, and protein expression. The hallmark of spontaneous APs in SAMs is a spontaneous depolarization during diastole that drives the membrane potential to threshold to trigger the next AP1,2. This &#34;pacemaker potential&#34; depends on the coordinated activity of many different membrane currents including the &#34;funny current&#34; (If), T- and L-type calcium currents, and the sodium-calcium exchanger current (INCX), which is driven by Ca2+ release from the sarcoplasmic reticulum3,4.
While acutely isolated mouse SAMs are an essential experimental preparation for the study of pacemaking, the isolation of SAMs from mice can be a challenging method to adopt because the indistinct anatomy and small size of the mouse SAN requires a nuanced microdissection and the combined enzymatic and mechanical dissociation of the cells requires careful optimization.
We provide here a detailed video demonstration of a protocol that has been successfully used to isolate SAMs from adult mice for patch clamp recordings5-8. To our knowledge, there is no such visual demonstration available from any other source. In addition, a new method is demonstrated in which isolated SAMs from adult mice can be maintained in vitro for several days, thereby permitting the introduction of proteins, genetically encoded reporter molecules or RNAi via adenoviral infection9.

<table border="0" cellpadding="0" cellspacing="0" width="649">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Sylgruard/Elastomer Kit</td>
			<td style="width:167px;">Dow Corning</td>
			<td colspan="2" style="width:237px;">184 SIL ELAST KIT 0.5KG</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Borosilicate 9&#34; pasteur pipettes</td>
			<td style="width:167px;">Fisher Scientific</td>
			<td>13-678-20C</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:247px;">Small, round bottomed culture tubes</td>
			<td style="width:167px;">Fisher Scientific</td>
			<td style="width:175px;">352059</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:247px;">Large, round bottomed culture tubes</td>
			<td style="width:167px;">Corning</td>
			<td style="width:175px;">14-959-11B</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:247px;">Elastase</td>
			<td style="width:167px;">Worthington Biochemical</td>
			<td style="width:175px;">LS002279</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Liberase TM</td>
			<td style="width:167px;">Roche</td>
			<td style="width:175px;">5401119001</td>
			<td>&#160;Tissue dissociation solution</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:247px;">Heparin</td>
			<td style="width:167px;">SAGENT Pharmaceuticals&#160;</td>
			<td style="width:175px;">NDC 25021-400-10</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Mouse Laminin</td>
			<td style="width:167px;">Corning</td>
			<td style="width:175px;">CB-354232</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">12 mm round glass coverslips</td>
			<td style="width:167px;">Fisher&#160;</td>
			<td style="width:175px;">12-545-80</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">24-well culture plate</td>
			<td style="width:167px;">Fisher</td>
			<td style="width:175px;">08-772-1</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Ad-mCherry</td>
			<td style="width:167px;">Vector Biolabs</td>
			<td style="width:175px;">1767</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Ad-eGFP</td>
			<td style="width:167px;">Vector Biolabs</td>
			<td style="width:175px;">1060</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:247px;">Plastic, disposable transfer pipette</td>
			<td style="width:167px;">Fisher Scientific</td>
			<td style="width:175px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Micro scissors</td>
			<td style="width:167px;">Fisher Scientific</td>
			<td style="width:175px;">17-467-496</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Dumont #4 Forceps</td>
			<td style="width:167px;">Roboz Instruments</td>
			<td style="width:175px;">RS-4904</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Tissue Forceps</td>
			<td style="width:167px;">Roboz Instruments</td>
			<td style="width:175px;">RS-8164</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Dissecting Iris Scissors</td>
			<td style="width:167px;">WPI, Inc.</td>
			<td style="width:175px;">501264</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Dissecting Pins</td>
			<td style="width:167px;">Fine Science Tools</td>
			<td style="width:175px;">26002-20</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">NaCl</td>
			<td>Sigma</td>
			<td>71376</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">KCl</td>
			<td>Sigma</td>
			<td>60128</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;">KH2PO4</td>
			<td>Sigma</td>
			<td>60353</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">HEPES</td>
			<td>Sigma</td>
			<td>54457</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">glucose</td>
			<td>Sigma</td>
			<td>G0350500</td>
			<td></td>
		</tr>
		<tr height="18">
			<td height="18" style="height:19px;">MgCl2</td>
			<td>Sigma</td>
			<td>M8266</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;">CaCl2</td>
			<td>Sigma</td>
			<td>C1016</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">taurine</td>
			<td>Sigma</td>
			<td>T0625</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">BSA</td>
			<td>Sigma</td>
			<td>A2153</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">K-glutamate</td>
			<td>Sigma</td>
			<td>G1501</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">K-aspartate</td>
			<td>Sigma</td>
			<td>A6558</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;">MgSO4</td>
			<td>Sigma</td>
			<td>M7506</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">creatine</td>
			<td>Sigma</td>
			<td>C0780</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">EGTA</td>
			<td>Sigma</td>
			<td>E3889</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Mg-ATP</td>
			<td>Sigma</td>
			<td>A9187</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Amphotericin-B</td>
			<td style="width:167px;">Fisher Scientific</td>
			<td style="width:175px;">1397-89-3</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Isoproterenol</td>
			<td style="width:167px;">Calbiochem</td>
			<td style="width:175px;">420355</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Media199</td>
			<td>Sigma</td>
			<td style="width:175px;">M4530</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:247px;">2,3-butanedione monoxime (BDM)</td>
			<td>Sigma</td>
			<td style="width:175px;">B0753</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Fetal Bovine Serum (FBS)</td>
			<td>Sigma</td>
			<td style="width:175px;">SH30071</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Bovine Serum Albumin (BSA)</td>
			<td>Sigma</td>
			<td style="width:175px;">A5611</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Insulin&#160;&#160;</td>
			<td>Sigma</td>
			<td style="width:175px;">I3146</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Transferrin</td>
			<td>Sigma</td>
			<td style="width:175px;">I3146</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:247px;">Selenium</td>
			<td>Sigma</td>
			<td style="width:175px;">I3146</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Penicillin</td>
			<td>GE Healthcare</td>
			<td style="width:175px;">SV30010</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Streptomycin</td>
			<td>Hyclone</td>
			<td style="width:175px;">SV30010</td>
			<td></td>
		</tr>
	</tbody>
</table>

methods for the isolation, culture, and functional characterization of sinoatrial node myocytes from adult mice

Sinoatrial node myocytes (SAMs) act as the natural pacemakers of the heart, initiating each heart beat by generating spontaneous action potentials (APs). These pacemaker APs reflect the coordinated activity of numerous membrane currents and intracellular calcium cycling. However the precise mechanisms that drive spontaneous pacemaker activity in SAMs remain elusive. Acutely isolated SAMs are an essential preparation for experiments to dissect the molecular basis of cardiac pacemaking. However, the indistinct anatomy, complex microdissection, and finicky enzymatic digestion conditions have prevented widespread use of acutely isolated SAMs. In addition, methods were not available until recently to permit longer-term culture of SAMs for protein expression studies. Here we provide a step-by-step protocol and video demonstration for the isolation of SAMs from adult mice. A method is also demonstrated for maintaining adult mouse SAMs in vitro and for expression of exogenous proteins via adenoviral infection. Acutely isolated and cultured SAMs prepared via these methods are suitable for a variety of electrophysiological and imaging studies.

The protocols described here have been previously employed to isolate spontaneously active SAMs from adult mice that are suitable for a variety of different patch clamp studies5-8. In addition, the protocols allow for isolated SAMs that can be maintained in culture for up to one week. Gene transfer into the cultured cells can be accomplished via adenoviral infection9. The results presented in this section derive from our previous work and are shown here as examples o...

Watch this Scientific Journal Video about Methods for the Isolation, Culture, and Functional Characterization of Sinoatrial Node Myocytes from Adult Mice at JoVE.com

Methods for the Isolation, Culture, and Functional Characterization of Sinoatrial Node Myocytes from Adult Mice

Methods are demonstrated for the isolation of sinoatrial node myocytes (SAMs) from adult mice for patch clamp electrophysiology or imaging studies. Isolated cells can be used directly or can be maintained in culture to permit expression of proteins of interest, such as genetically encoded reporters.

Sinoatrial node myocytes (SAMs) act as the natural pacemakers of the heart, initiating each heart beat by generating spontaneous action potentials (APs). ...

The overall goal of this procedure is to isolate spontaneously active sinoatrial node myocytes from mice for short or medium-term electrophysiological or imaging experiments. Isolated sinoatrial node myocytes are important for the study of cardiac pacemaking mechanisms, in particular the study of specific ion currents or timing of intracellular calcium release. But relatively few labs use isolated sinoatrial myocytes from mice in part because it is very difficult to learn the procedure from written methods alone.After preparing all the required solutions for the isolation, remove the fur from the animal's chest with scissors. Then transect the ribcage to expose the chest cavity using external tissue forceps and dissection scissors. Rinse the chest cavity with two milliliters of warmed complete Tyrode's with heparin.Under a dissecting microscope, carefully remove the lungs and thymus using internal scissors and dissection forceps. While gently holding the apex of the heart, carefully cut the inferior vena cava and the aorta to remove the heart from the chest cavity. Then transfer the heart to one of the silicone dissection dishes and then rinse it with two to four milliliters of warmed heparinized complete Tyrode's.Orient the heart such that the posterior vessels are visible and facing up. Next, immobilize the heart by pinning it through the apex into the silicone dissection dish. Afterward, locate the groove between the ventricles and the atria.Using the internal dissection scissors, make an incision at the groove while keeping it close to the ventricles. Flush the groove and the incision with additional warmed heparinized complete Tyrode's as needed to allow a clear view of the atria and the valves. Then continue to cut along the groove to separate the atria from the ventricles.Subsequently, transfer the atrial tissue to the second silicone dissection dish and rinse it with three milliliters of warmed heparinized complete Tyrode's. Afterward, while stretching the preparation gently, pin the tissue through the inferior vena cava. Then flip the tissue so that the animal's right atrium is now on the experimenter's left side and the left atrium is on the right side of the experimenter.It's very important to obtain and recognize orientation in order to isolate the correct tissue. Proceed to pin the tissue through the superior vena cava, then the right and left atrial appendages. Remove any remaining fat or other tissue to allow a clear view of the preparation.Subsequently, open the anterior wall of the atria by cutting through the venae cavae. Rotate the dish as necessary to dissect both the superior and inferior venae cavae. Reposition the pins as necessary to visualize the inter-atrial septum.Then cut along the inter-atrial septum to remove the left atrium. Re-pin the preparation, stretch it gently, and remove the fat from behind the sinoatrial node. After that, remove the right atrial appendage then free the sinoatrial node by cutting along the crista terminalis which appears as a dark orange streak bordering the atrial appendage.Re-pin or unpin the nodal tissue and cut it laterally to produce three equally-sized strips. In this procedure, using the narrow fire polished pipette, transfer three strips of sinoatrial node tissue to the first of the three small round bottom tubes containing 2.5 milliliters of low calcium magnesium Tyrode's and incubate for five minutes. After five minutes, transfer the tissue strips to the second small round bottom tube containing 2.5 milliliters of low calcium magnesium Tyrode's.Wash the tissue strips by gently swirling the tube or by gently pipetting with the narrow pipette. Do not invert the tube. Then transfer the tissue strips to the third small round bottom tube containing 2.5 milliliters of low calcium magnesium Tyrode's and repeat the washing step.Afterward, transfer the strips to the large round bottom tube containing 2.5 milliliters of low calcium magnesium Tyrode's with enzymes. Mix every five minutes by gently swirling the tube. Following enzyme digestion, use a narrow fire polished pipette to gently transfer the tissue strips to the first of the three small round bottom tubes containing modified KB solution.Then transfer the strips through the second and third small round bottom tubes to wash the tissue before transferring to the large round bottom tube that contains KB solution. Using the larger fire polished pipette, dissociate the cells in the large round bottom tube by constant trituration, taking care to keep the dissociation tube submerged in the 35 degree Celsius water bath and to avoid introducing bubbles into the solution. We have found that a forceful expulsion of the solution at a frequency of approximately one per second or one Hertz works best.Now add 75 microliters of sodium chloride calcium chloride adaptation solution to the tissues. Swirl gently to mix and incubate them for five minutes. Continue to add calcium in increments as outlined in the written protocol.Following calcium re-adaptation, collect the sinoatrial myocytes by allowing them to settle for about 10 minutes or by centrifugation at 2, 000 times g for three minutes. For acutely isolated cells, gently remove and discard about five milliliters of the supernatant using a transfer pipette. Then store the cells at room temperature for up to eight hours for patch clamp experiments.Subsequently, functional assessments of the isolated sinoatrial myocytes can be done using patch clamp recordings for spontaneous action potentials and membrane currents. Spontaneously active sinoatrial myocytes can be maintained in culture for up to six days. The cultured cells retain an overall morphology that is very similar to that of the acutely isolated sinoatrial myocytes with no significant changes in the average length, width, cross-section area, or membrane capacitance of cultured cells compared to the acutely isolated cells.The cells are suitable for a range of experimental studies such as current and voltage clamp recordings. Shown here as examples are spontaneous action potentials and the funny current. Once mastered, the sinoatrial node dissection, isolation, and calcium re-introduction can be completed in about two hours so that you can have cells ready to go for your experiments.While attempting this procedure, it's important to remember that the orientation of the tissue is critical for a good dissection and that the enzymatic and mechanical dissociation steps should be optimized as outlined in the text. Following this procedure, the isolated sinoatrial node myocytes can be used for a variety of experiments including single-cell electrophysiology, calcium imaging and immunocytochemistry. The cells can also be maintained in culture for experiments that require gene manipulation or the expression of reporter molecules.After watching this video, you should have a good understanding of how to isolate sinoatrial myocytes from adult mice. Best of luck with your experiments.

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Research

JoVE Journal

Biology

Primary Culture of Adult Rat Heart Myocytes

Cultured primary adult rodent heart cells are an important model system for cardiovascular research. Nevertheless, establishment of robust, viable cultured adult myocytes can be a technically challenging, rate-limiting step for many researchers. Here we described a protocol to obtain a high yield of adult rat heart myocytes that remain viable in culture for several days. The heart is isolated and perfused with collagenase and protease under low Ca2+ conditions to recover single myocytes. Ca2+-tolerant cells are obtained by stepwise increases in extracellular Ca2+ concentration in three subsequent wash steps. Cells are filtered, resuspended in culture medium, and plated on laminin coated slips. Cultured myocytes obtained using this protocol are viable for up to four days and are suitable for most experiments including electrophysiology, biochemistry, imaging and molecular biology.

In this paper, we described a typical way to isolate and culture adult rat heart myocytes. Collagenase and protease are used to digest and isolate single myocytes. Myocytes cultured follow this protocol meet most experiment requirements.

Cultured primary adult rodent heart cells are an important model system for cardiovascular research.  Nevertheless, establishment of robust, viable ...

Isolation and Genetic Manipulation of Adult Cardiac Myocytes for Confocal Imaging

Cardiac myocytes isolated from adult hearts are widely accepted as a model somewhere half way between embryonic and neonatal muscle cells on one side and a working heart on the other. Thus, cardiomyocytes serve as good models for cardiac cellular physiology and pathophysiology, for pharmaceutical investigations as well as for the exploration of transgenic animal models. Here we describe a method of isolating the cells from the heart. Furthermore we show how a genetic manipulation on cardiac myocytes can be performed without breeding a transgenic animal: This is the combination of long term culture (1 week) and adenoviral gene transfer. The latter one is described from the construction of the virus to the transduction of the cells. It can be used for the expression of genetically encoded biosensors (GEBs), fluorescent fusion proteins, but also for protein over expression and down regulation, e.g. using RNAi. Here we provide an example for the expression of a fusion protein staining a subcellular structure (Golgi). Such protein expression can be visualized by confocal imaging of z-stacks for a 3D-reconstruction of subcellular structures. The protocol comprises state-of-the-art in cell culture, molecular biology and biophysics and thus provides an approach for exploring new horizons in cellular cardiology.

Adult cardiac myocytes are primary cells that can be isolated from animal hearts and cultured for several days. Within this culture period adenoviral gene transfer can be used to express genetically encoded biosensors (GEBs) or fluorescent fusion proteins. Both approaches allow cellular investigations by means of confocal microscopy.

Cardiac myocytes isolated from adult hearts are widely accepted as a model somewhere half way between embryonic and neonatal muscle cells on one side and ...

Isolation and Culture of Pulmonary Endothelial Cells from Neonatal Mice

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

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

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

Isolation and Culture of Adult Epithelial Stem Cells from Human Skin

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

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

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

Isolation and Culture of Individual Myofibers and their Satellite Cells from Adult Skeletal Muscle

Muscle regeneration in the adult is performed by resident stem cells called satellite cells. Satellite cells are defined by their position between the basal lamina and the sarcolemma of each myofiber. Current knowledge of their behavior heavily relies on the use of the single myofiber isolation protocol. In 1985, Bischoff described a protocol to isolate single live fibers from the Flexor Digitorum Brevis (FDB) of adult rats with the goal to create an in vitro system in which the physical association between the myofiber and its stem cells is preserved 1. In 1995, Rosenblattmodified the Bischoff protocol such that myofibers are singly picked and handled separately after collagenase digestion instead of being isolated by gravity sedimentation 2, 3. The Rosenblatt or Bischoff protocol has since been adapted to different muscles, age or conditions 3-6. The single myofiber isolation technique is an indispensable tool due its unique advantages. First, in the single myofiber protocol, satellite cells are maintained beneath the basal lamina. This is a unique feature of the protocol as other techniques such as Fluorescence Activated Cell Sorting require chemical and mechanical tissue dissociation 7. Although the myofiber culture system cannot substitute for in vivo studies, it does offer an excellent platform to address relevant biological properties of muscle stem cells. Single myofibers can be cultured in standard plating conditions or in floating conditions. Satellite cells on floating myofibers are subjected to virtually no other influence than the myofiber environment. Substrate stiffness and coating have been shown to influence satellite cells' ability to regenerate muscles 8, 9 so being able to control each of these factors independently allows discrimination between niche-dependent and -independent responses. Different concentrations of serum have also been shown to have an effect on the transition from quiescence to activation. To preserve the quiescence state of its associated satellite cells, fibers should be kept in low serum medium 1-3. This is particularly useful when studying genes involved in the quiescence state. In serum rich medium, satellite cells quickly activate, proliferate, migrate and differentiate, thus mimicking the in vivo regenerative process 1-3. The system can be used to perform a variety of assays such as the testing of chemical inhibitors; ectopic expression of genes by virus delivery; oligonucleotide based gene knock-down or live imaging. This video article describes the protocol currently used in our laboratory to isolate single myofibers from the Extensor Digitorum Longus (EDL) muscle of adult mice (6-8 weeks old).

Isolation and culture of myofibers is the gold standard in vitro system to study the transition of satellite cells through quiescence, activation and differentiation. Importantly, the single myofiber culture system preserves the myofiber/stem cell association, which is an essential component of the muscle stem cell niche.

Muscle  regeneration in the adult is performed by resident stem cells called satellite  cells. Satellite cells are defined by  their position between the ...

Isolation, Culture, and Functional Characterization of Adult Mouse Cardiomyoctyes

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

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

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

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

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

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

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

Isolation and 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 ...

Isolation, Characterization, and Differentiation of Cardiac Stem Cells from the Adult Mouse Heart

Myocardial infarction (MI) is a leading cause of morbidity and mortality around the world. A major goal of regenerative medicine is to replenish the dead myocardium after MI. Although several strategies have been used to regenerate myocardium, stem cell therapy remains a major approach to replenish the dead myocardium of an MI heart. Accumulating evidence suggests the presence of resident cardiac stem cells (CSCs) in the adult heart and their endocrine and/or paracrine effects on cardiac regeneration. However, CSC isolation and their characterization and differentiation toward myocardial cells, especially cardiomyocytes, remains a technical challenge. In the present study, we provided a simple method for the isolation, characterization, and differentiation of CSCs from the adult mouse heart. Here, we describe a density gradient method for the isolation of CSCs, where the heart is digested by a 0.2% collagenase II solution. To characterize the isolated CSCs, we evaluated the expression of CSCs/cardiac markers Sca-1, NKX2-5, and GATA4, and pluripotency/stemness markers OCT4, SOX2, and Nanog. We also determined the proliferation potential of isolated CSCs by culturing them in a Petri dish and assessing the expression of the proliferation marker Ki-67. For evaluating the differentiation potential of CSCs, we selected seven- to ten-days cultured CSCs. We transferred them to a new plate with a cardiomyocyte differentiation medium. They are incubated in a cell culture incubator for 12 days, while the differentiation medium is changed every three days. The differentiated CSCs express cardiomyocyte-specific markers: actinin and troponin I. Thus, CSCs isolated with this protocol have stemness and cardiac markers, and they have a potential for proliferation and differentiation toward cardiomyocyte lineage.

The overall goal of this article is to standardize the protocol for the isolation, characterization, and differentiation of cardiac stem cells (CSCs) from the adult mouse heart. Here, we describe a density gradient centrifugation method to isolate murine CSCs and elaborated methods for CSC culture, proliferation, and differentiation into cardiomyocytes.

Myocardial infarction (MI) is a leading cause of morbidity and mortality around the world. A major goal of regenerative medicine is to replenish the dead ...

Isolation and Characterization of Adult Cardiac Fibroblasts and Myofibroblasts

Cardiac fibrosis in response to injury is a physiological response to wound healing. Efforts have been made to study and target fibroblast subtypes that mitigate fibrosis. However, fibroblast research has been hindered due to the lack of universally acceptable fibroblast markers to identify quiescent as well as activated fibroblasts. Fibroblasts are a heterogenous cell population, making them difficult to isolate and characterize. The presented protocol describes three different methods to enrich fibroblasts and myofibroblasts from uninjured and injured mouse hearts. Using a standard and reliable protocol to isolate fibroblasts will enable the study of their roles in homeostasis as well as fibrosis modulation.

Obtaining a pure population of fibroblasts is crucial to studying their role in wound repair and fibrosis. Described here is a detailed method to isolate fibroblasts and myofibroblasts from uninjured and injured mouse hearts followed by characterization of their purity and functionality by immunofluorescence, RTPCR, fluorescence-assisted cell sorting, and collagen gel contraction.

Cardiac fibrosis in response to injury is a physiological response to wound healing. Efforts have been made to study and target fibroblast subtypes that ...