Name: isolation of primary patient-specific aortic smooth muscle cells and semiquantitative real-time contraction measurements in vitro
Uploaded: 2022-02-15T13:30:00
Description: Watch this Scientific Journal Video about Isolation of Primary Patient-specific Aortic Smooth Muscle Cells and Semiquantitative Real-time Contraction Measurements In Vitro at JoVE.com

We would like to gratefully acknowledge Tara van Merrienboer, Albert van Wijk, Jolanda van der Velden, Jan D. Blankensteijn, Lan Tran, Peter L. Hordijk, the PAREL-AAA team, and all vascular surgeons of the Amsterdam UMC, Zaans Medisch Centrum, and Dijklander hospital for providing materials and support for this study.&#160;This study is funded by the Dutch Heart Foundation, Dekkerbeurs senior clinical scientist award, project no. 2019T065.

NOTE: Aortic biopsies were obtained during open aneurysm repair in Amsterdam University Medical Centers, VU University Medical center, Amsterdam, Zaans Medisch Centrum, Zaandam and Dijklander hospital, Hoorn, the Netherlands. Control aortic tissue was obtained from the piece of the aorta attached to the renal artery harvested for kidney transplants. Only patients above the age of 18 were included, and all patients gave their informed consent to participate in the study. All material was collected in accordance with the r...

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E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Betaglycan+(TGFBR3)+up-regulation+correlates+with+increased+TGF-&#946;+signaling+in+Marfan+patient+fibroblasts+in+vitro.">Betaglycan (TGFBR3) up-regulation correlates with increased TGF-&#946; signaling in Marfan patient fibroblasts in vitro.</a> Cardiovascular Pathology. 32, 44-49 (2018).</li><li>Chen, J., Li, H., SundarRaj, N., Wang, J. H. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alpha-smooth+muscle+actin+expression+enhances+cell+traction+force.">Alpha-smooth muscle actin expression enhances cell traction force.</a> Cell Motility and the Cytoskeleton. 64 (4), 248-257 (2007).</li><li>Peyton, S. R., Putnam, A. 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L., Minnear, F. L., Heimark, R. L., Vincent, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rearrangement+of+adherens+junctions+by+transforming+growth+factor-&#946;1:+role+of+contraction.">Rearrangement of adherens junctions by transforming growth factor-&#946;1: role of contraction.</a> American Journal of Physiology-Lung Cellular and Molecular Physiology. 276 (4), 582-595 (1999).</li><li>Hu, N., 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=Comparison+between+ECIS+and+LAPS+for+establishing+a+cardiomyocyte-based+biosensor.">Comparison between ECIS and LAPS for establishing a cardiomyocyte-based biosensor.</a> Sensors and Actuators B: Chemical. 185, 238-244 (2013).</li><li>Peters, M. F., Lamore, S. D., Guo, L., Scott, C. W., Kolaja, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+stem+cell-derived+cardiomyocytes+in+cellular+impedance+assays:+bringing+cardiotoxicity+screening+to+the+front+line.">Human stem cell-derived cardiomyocytes in cellular impedance assays: bringing cardiotoxicity screening to the front line.</a> Cardiovascular Toxicology. 15 (2), 127-139 (2015).</li><li>Zhang, S., Yang, Y., Kone, B. C., Allen, J. C., Kahn, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insulin-stimulated+cyclic+guanosine+monophosphate+inhibits+vascular+smooth+muscle+cell+migration+by+inhibiting+Ca/calmodulin-dependent+protein+kinase+II.">Insulin-stimulated cyclic guanosine monophosphate inhibits vascular smooth muscle cell migration by inhibiting Ca/calmodulin-dependent protein kinase II.</a> Circulation. 107 (11), 1539-1544 (2003).</li><li>Halterman, J. A., Kwon, H. M., Zargham, R., Bortz, P. D. S., Wamhoff, B. 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R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thrombomodulin+induces+a+quiescent+phenotype+and+inhibits+migration+in+vascular+smooth+muscle+cells+in+vitro.">Thrombomodulin induces a quiescent phenotype and inhibits migration in vascular smooth muscle cells in vitro.</a> Annals of Vascular Surgery. 30, 149-156 (2016).</li><li>Burger, 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=Molecular+phenotyping+and+functional+assessment+of+smooth+muscle+like-cells+with+pathogenic+variants+in+aneurysm+genes+ACTA2,+MYH11,+SMAD3+and+FBN1.">Molecular phenotyping and functional assessment of smooth muscle like-cells with pathogenic variants in aneurysm genes ACTA2, MYH11, SMAD3 and FBN1.</a> Human Molecular Genetics. , (2021).</li><li>Yeung, K. 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=Transdifferentiation+of+human+dermal+fibroblasts+to+smooth+muscle-like+cells+to+study+the+effect+of+MYH11+and+ACTA2+mutations+in+aortic+aneurysms.">Transdifferentiation of human dermal fibroblasts to smooth muscle-like cells to study the effect of MYH11 and ACTA2 mutations in aortic aneurysms.</a> Human Mutation. 38 (4), 439-450 (2017).</li></ol>

This paper presents a method to measure SMC contraction in vitro, based on the changes in impedance and surface occupation. First, the isolation, culturing, and expansion of patient-specific primary human SMCs and skin fibroblasts is described, followed by how to use them for contraction measurements. 
A limitation of the study is related to obtaining the cells through an explant protocol. The cells that proliferate from the biopsy might have different properties than the original tis...

Smooth muscle cells (SMCs) are the predominant cell type in the aortic medial layer, the thickest layer of the aorta. Within the wall, they are radially oriented and are involved in, among other functions, vasoconstriction and vasodilation1. The SMC contractile machinery is involved in the transmission of force in the aorta through the functional link with the extracellular matrix2. Mutations in genes encoding for the proteins of the SMC contractile apparatus, such as smooth muscle myosin heavy chain (MYH11) and smooth muscle actin (ACTA2), have been related to cases of familial thoracic aortic aneurysms, underscoring the relevance of SMC contraction in maintaining the structural and functional integrity of the aorta1,2. Furthermore, mutations in the TGF&#946; signaling pathway are also associated with aortic aneurysms, and their effects in aortic aneurysm pathophysiology can also be studied in skin fibroblasts3.
High-throughput measurement of SMC contraction in vitro is challenging. As SMC contractility cannot be measured in vivo in humans, in vitro assays on human cells present a feasible alternative. Moreover, abdominal aortic aneurysm (AAA) development in animal models is either chemically induced by, for example, elastase perfusion, or caused by a specific mutation. Therefore, animal data are not comparable to AAA development in humans, which mostly has a multifactorial cause, such as smoking, age, and/or atherosclerosis. In vitro SMC contractility has so far been mainly measured by traction force microscopy4,5, quantification of Fura-2 fluorescence intracellular calcium fluxes6, and collagen wrinkling assays7. While traction force microscopy provides invaluable numeric insight into the forces generated by a single cell, it is not suitable for high-throughput screening due to the complex mathematical data processing and the analysis of one cell at a time, meaning that it is very time-consuming to measure a representative number of cells per donor. Fura-2 dye and collagen wrinkling assays allow the superficial determination of contraction and do not give a precise numerical output, making them less suitable for discriminating patient-specific differences. Impaired SMC contraction in cells derived from the aorta of abdominal aortic aneurysm patients was demonstrated for the first time by optimizing a novel method for measuring SMC contraction in vitro8. This was done by repurposing the electric cell-substrate impedance sensing (ECIS) method. ECIS is a real-time, medium-throughput assay for the quantification of adherent cell behavior and contraction9,10,11 such as SMC growth and behavior in wound-healing and migration assays12,13,14. The exact method is described in the protocol section. In this optimized way, the ECIS can also be used to study fibroblast contraction due to their similar size and morphology.
The aim of this paper is to provide a stepwise description of the method for measuring SMC contraction in vitro using ECIS8 and comparing the contraction between control and patient SMCs. First, the isolation and culturing of primary SMCs from control and patient aortic biopsies is explained, which can be used for contraction measurement. Second, contraction measurements and analysis, alongside the verification of SMC marker expression, are described. Furthermore, this paper describes the method for the isolation of patient-specific dermal fibroblasts whose contraction can be measured using the same methodology. These cells can be used for patient-specific studies focused on aortic aneurysm or other cardiovascular pathologies15 or prognostic studies using a transdifferentiation protocol that allows contraction measurement prior to aneurysm surgery16.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>96-well Array</td>
			<td>Applied Biophysics</td>
			<td>96W10idf PET</td>
			<td>Array used to measure contraction in the ECIS setup</td>
		</tr>
		<tr>
			<td>Custodiol</td>
			<td>Dr. Franz H&#246;hler Chemie GmbH</td>
			<td>RVG 12801</td>
			<td>Solution used to transfer tissue in from surgery room to laboratorium</td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxide</td>
			<td>Sigma-Aldrich</td>
			<td>472301</td>
			<td>Solution used to dilute ionomycin</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Gibco</td>
			<td>26140079</td>
			<td>Addition to cell culture medium</td>
		</tr>
		<tr>
			<td>Ham&#39;s F-10 Nutrient Mix</td>
			<td>Gibco</td>
			<td>11550043</td>
			<td>Medium used to culture skin fibroblasts</td>
		</tr>
		<tr>
			<td>Human Vascular Smooth Muscle Cell Basal Medium (formerly &#39;&#39;Medium 231&#39;&#39;)</td>
			<td>Gibco</td>
			<td>M231500</td>
			<td>Medium used to culture smooth muscle cells</td>
		</tr>
		<tr>
			<td>Invitrogen countess II</td>
			<td>Thermo Fisher Scientific</td>
			<td>AMQAX1000</td>
			<td>Automated cell counter</td>
		</tr>
		<tr>
			<td>Ionomycin calcium salt from Streptomyces conglobatus</td>
			<td>Sigma-Aldrich</td>
			<td>I0634-1MG</td>
			<td>Compound used for contraction stimulation</td>
		</tr>
		<tr>
			<td>NaCl 0.9%</td>
			<td>Fresenius Kabi</td>
			<td>B230561</td>
			<td>Solution used to transfer tissue in from surgery room to laboratorium</td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin</td>
			<td>Gibco</td>
			<td>15140122</td>
			<td>Antibiotics used for cell culture medium</td>
		</tr>
		<tr>
			<td>Phospathe buffered saline</td>
			<td>Gibco</td>
			<td>10010023</td>
			<td>Used to wash cells</td>
		</tr>
		<tr>
			<td>Quick-RNA Miniprep Kit</td>
			<td>Zymo Research</td>
			<td>R1055</td>
			<td>Kit used for RNA isolation</td>
		</tr>
		<tr>
			<td>Smooth Muscle Growth Supplement (SMGS)</td>
			<td>Gibco</td>
			<td>S00725</td>
			<td>Supplement which is added to smooth muscle cell culture medium</td>
		</tr>
		<tr>
			<td>SuperScript VILO cDNA Synthesis Kit</td>
			<td>Thermo Fisher Scientific</td>
			<td>11754250</td>
			<td>Kit used for cDNA synthesis</td>
		</tr>
		<tr>
			<td>SYBR Green PCR Master Mix</td>
			<td>Thermo Fisher Scientific</td>
			<td>4309155</td>
			<td>Reagent for qPCR</td>
		</tr>
		<tr>
			<td>Trypsin-EDTA</td>
			<td>Gibco</td>
			<td>15400-054</td>
			<td>Used to trypsinize cells</td>
		</tr>
		<tr>
			<td>ZTheta</td>
			<td>Applied Biophysics</td>
			<td>ZTheta</td>
			<td>ECIS instrument used for contraction measurements</td>
		</tr>
	</tbody>
</table>

isolation of primary patient-specific aortic smooth muscle cells and semiquantitative real-time contraction measurements in vitro

Smooth muscle cells (SMCs) are the predominant cell type in the aortic media. Their contractile machinery is important for the transmission of force in the aorta and regulates vasoconstriction and vasodilation. Mutations in genes encoding for the SMC contractile apparatus proteins are associated with aortic diseases, such as thoracic aortic aneurysms. Measuring SMC contraction in vitro is challenging, especially in a high-throughput manner, which is essential for screening patient material. Currently available methods are not suitable for this purpose. This paper presents a novel method based on electric cell-substrate impedance sensing (ECIS). First, an explant protocol is described to isolate patient-specific human primary SMCs from aortic biopsies and patient-specific human primary dermal fibroblasts for the study of aortic aneurysms. Next, a detailed description of a new contraction method is given to measure the contractile response of these cells, including the subsequent analysis and suggestion for comparing different groups. This method can be used to study the contraction of adherent cells in the context of translational (cardiovascular) studies and patient and drug screening studies.

To test the reproducibility of this method, the method was first validated using control SMCs only. To determine interexperimental measurement reproducibility, two independent measurements of all included control and patient cell lines were plotted as a Bland-Altman plot (Figure 3B). The plot demonstrated that this method does not show variability outside the confidence interval, except for one outlier cell line. Furthermore, these results demonstrated that two wells seeded within the same e...

Watch this Scientific Journal Video about Isolation of Primary Patient-specific Aortic Smooth Muscle Cells and Semiquantitative Real-time Contraction Measurements In Vitro at JoVE.com

Isolation of Primary Patient-specific Aortic Smooth Muscle Cells and Semiquantitative Real-time Contraction Measurements In Vitro

This paper describes an explant culture-based method for the isolation and culturing of primary, patient-specific human aortic smooth muscle cells and dermal fibroblasts. Furthermore, a novel method is presented for measuring cell contraction and subsequent analysis, which can be used to study patient-specific differences in these cells.

Isolation of Primary Patient-specific Aortic Smooth Muscle Cells and Semiquantitative Real-time Contraction Measurements In Vitro

Smooth muscle cells (SMCs) are the predominant cell type in the aortic media. Their contractile machinery is important for the transmission of force in ...

This method allows researchers to study the cell contraction of multiple patient cell line simultaneously. It allows us to study diseases quicker and more efficiently. This technique allows us to quantify cell contraction in real time.Within an hour, we can obtain the contraction values of dozens of cells. We demonstrated for the first time that muscle cell contraction is decreased in a group of patients with aortic aneurysms. This can be a new biomarker or target for medical therapy.Begin by sterilizing two pairs of surgical forceps and a scalpel by immersing them in 70%ethanol and subsequently wiping them dry. Then pipette two milliliters of SMC medium in a Petri dish in which the tissue dissection will be performed. Next pipette 2.5 milliliters of SMC medium into two T-25 flasks.Swirl the flasks around so that the small volume of medium covers the whole surface. Visually inspect the biopsy, identifying the three aortic layers by the presence of atherosclerotic plaques on the intima side and slimy connective tissue on the a adventitial side to distinguish the layers. To isolate SMCs from the media, remove the other two layers by placing the tissue with intima plaque side up first, then remove the solid plaque by pulling it away from the tissue with forceps while pushing the tissue down with the second pair of forceps until the pink uniform medial layer is visible.Now flip the tissue and repeat the same procedure by pulling off the adventitial layer, being sure to remove all visible parts in as many attempts as needed as this layer will not detach from the media easily. Once the media layer is isolated, cut the tissue into cubes by pressing the media down with forceps and cutting the tissue in one direction using the scalpel making clean unidirectional cuts to minimize damage. Place 10 to 20 of these tissue pieces in the upper quarter of the T-25 flak using forceps.After sterilizing two pairs of surgical forceps and a scalpel as described previously, pipette two milliliters of fibroblast medium in a Petri dish in which the tissue dissection will be performed. Then pipette 2.5 milliliters of fibroblast medium into two T-25 flasks and swirl the flasks around so that the small volume of medium covers the whole surface. Visually inspect the biopsy for identifying the epidermis with a recognizable skin surface, sometimes with visible hair, then look for yellow and slimy subcutaneous fat on the opposite side.The layer between the epidermis and the subcutaneous fat is the dermis, the source of viable fibroblasts. To isolate fibroblasts from the dermis, remove the other two layers by placing the tissue on the dermis side to make all three layers visible. Then hold the tissue down with forceps and cut away the whole epidermis in one clean line without damaging the tissue.Now flip the tissue and repeat the same procedure by cutting within the dermis parallel to the border with the subcutaneous fat. Once the dermis is isolated, cut the tissue into cubes pressing the tissue down with forceps and cutting the tissue in one direction using the scalpel. Then place 10 to 20 of these tissue pieces in the upper quarter of the T-25 flask using the forceps.Count the cells using an automated cell counter and seed the SMCs in triplicate at a seeding density of 30, 000 cells per well in 200 microliters of SMC medium in the gelatin coated ECIS plate. Place the plate with the SMCs into the ECIS's 96-well holder in the cell culture incubator. Double-click on the ECIS Applied BioPhysics software to open the program and press the Setup button.Check if all the electrodes have contact with the holder in the left lower panel labeled Well Configuration. If the electrodes are not properly connected, adjust the plate in the holder before starting the measurement. Now select the plate type in the same panel by clicking Array type.Next, prepare two pipettes set at two microliter and 150 microliter volume. Before starting the stimulation, press Mark in the software and place a comment. To stimulate the cells, remove the lid and place it on a sterile surface inside the incubator.Then induce SMC contraction by pipetting two microliters of the ionomycin working solution into each well as quickly as possible. Once all the cells have been stimulated, mix the medium in the wells using the second pipette. To determine interexperimental measurement reproducibility, two independent measurements of all included control and patient cell lines were plotted as a Bland-Altman plot, demonstrating that this method did not show variability outside the confidence interval, except for one outlier cell line.Two wells seeded with the same experiment and stimulated simultaneously showed practically the same contractual response curve. For validating whether the shown response was a contraction and not osmotic stress because of ionomycin stimulation, the medium was replaced after stimulation and the behavior of the cells was recorded, which showed that the stimulated cells started spreading over the electrode again. The contractile response in SMCs derived from healthy, non-dilated aortas showed a median response of 61%compared to the median response of 52%from abdominal aortic aneurysm patients.The mean contractile response of the control group was used to identify four patients who had lower contraction values than the normal values. The Western blot analysis and subsequent quantification confirmed that the cells express SMC markers. For determining the proliferative capacity of the SMC, qPCR was performed for Ki67.Ki67 expression was detectable in all cells, but did not correlate with the contractile output. When stimulating the cells for contraction, remember not to pipet too many wells at the same time and tried to pipet as fast as possible. This procedure may need some practice.Using this method, we have divided the patients based on their contraction and to lower normal contracting which allowed us to investigate these patient and the links to their clinical characteristics such as smoking.

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Biology

Isolation of Human Umbilical Arterial Smooth Muscle Cells (HUASMC)

The human umbilical cord (UC) is a biological sample that can be easily obtained just after birth. This biological sample is, most of the time, discarded and their collection does not imply any added risk to the newborn or mother s health. Moreover no ethical concerns are raised. The UC is composed by one vein and two arteries from which both endothelial cells (ECs) 1 and smooth muscle cells (SMCs) 2, two of the main cellular components of blood vessels, can be isolated. In this project the SMCs were obtained after enzymatic treatment of the UC arteries accordingly the experimental procedure previously described by Jaffe et al 3. After cell isolation they were kept in t-flash with DMEM-F12 supplemented with 5% of fetal bovine serum and were cultured for several passages. Cells maintained their morphological and other phenotypic characteristics in the different generations. The aim of this study was to isolate smooth muscle cells in order to use them as models for future assays with constrictor drugs, isolate and structurally characterize L-type calcium channels, to study cellular and molecular aspects of the vascular function 4 and to use them in tissue engineering.

Isolation of Human Umbilical Arterial Smooth Muscle Cells HUASMC

The umbilical cords are used to isolate smooth muscle cells by different ways. In this work we used the enzymatic treatment to isolated smooth muscle cells.

The human umbilical cord (UC) is a biological sample that can be easily obtained just after birth. This biological sample is, most of the time, discarded ...

Isolation and Primary Culture of Rat Hepatic Cells

Primary hepatocyte culture is a valuable tool that has been extensively used in basic research of liver function, disease, pathophysiology, pharmacology and other related subjects. The method based on two-step collagenase perfusion for isolation of intact hepatocytes was first introduced by Berry and Friend in 1969 1 and, since then, has undergone many modifications. The most commonly used technique was described by Seglenin 1976 2. Essentially, hepatocytes are dissociated from anesthetized adult rats by a non-recirculating collagenase perfusion through the portal vein. The isolated cells are then filtered through a 100 &mu;m pore size mesh nylon filter, and cultured onto plates. After 4-hour culture, the medium is replaced with serum-containing or serum-free medium, e.g. HepatoZYME-SFM, for additional time to culture. These procedures require surgical and sterile culture steps that can be better demonstrated by video than by text. Here, we document the detailed steps for these procedures by both video and written protocol, which allow consistently in the generation of viable hepatocytes in large numbers.

Primary hepatocytes provide a valuable tool to evaluate biochemical, molecular, and metabolic functions in a physiologically relevant experimental system. We describe a reliable protocol for rat in situ liver perfusion, which consistently generates viable hepatocytes up to 1.0 &times; 108 cells per preparation with cell viability between 88 ~ 96%.

Primary hepatocyte culture is a valuable tool that has been extensively used in basic research of liver function, disease, pathophysiology, pharmacology ...

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 ...

Real Time Measurements of Membrane Protein:Receptor Interactions Using Surface Plasmon Resonance (SPR)

Protein-protein interactions are pivotal to most, if not all, physiological processes, and understanding the nature of such interactions is a central step in biological research. Surface Plasmon Resonance (SPR) is a sensitive detection technique for label-free study of bio-molecular interactions in real time. In a typical SPR experiment, one component (usually a protein, termed 'ligand') is immobilized onto a sensor chip surface, while the other (the 'analyte') is free in solution and is injected over the surface. Association and dissociation of the analyte from the ligand are measured and plotted in real time on a graph called a sensogram, from which pre-equilibrium and equilibrium data is derived. Being label-free, consuming low amounts of material, and providing pre-equilibrium kinetic data, often makes SPR the method of choice when studying dynamics of protein interactions. However, one has to keep in mind that due to the method's high sensitivity, the data obtained needs to be carefully analyzed, and supported by other biochemical methods. 
SPR is particularly suitable for studying membrane proteins since it consumes small amounts of purified material, and is compatible with lipids and detergents. This protocol describes an SPR experiment characterizing the kinetic properties of the interaction between a membrane protein (an ABC transporter) and a soluble protein (the transporter's cognate substrate binding protein).

Real Time Measurements of Membrane Protein:Receptor Interactions Using Surface Plasmon Resonance SPR

Surface Plasmon Resonance (SPR) is a label-free method for detecting bio-molecular interactions in real time. Herein, a protocol for a membrane protein:receptor interaction experiment is described, while discussing the pros and cons of the technique.

Protein-protein interactions are pivotal to most, if not all, physiological processes, and  understanding the nature of such interactions is a central ...

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 Murine Coronary Vascular Smooth Muscle Cells

While the isolation and culture of vascular smooth muscle cells (VSMCs) from large vessels is well established, we sought to isolate and culture VSMCs from the coronary circulation. Hearts with intact aortic arches were removed and perfused via retrograde Langendorff with digestion solution containing 300 Units/ml of collagenase type II, 0.1 mg/ml soybean trypsin inhibitor and 1 M CaCl2. The perfusates were collected at 15 min intervals for 90 min, pelleted by centrifugation, resuspended in plating media, and plated on tissue culture dishes. VSMCs were characterized by presence of SM22&#945;, &#945;-SMA, and vimentin. One of the main advantages of using this technique is the ability to isolate VSMCs from the coronary circulation of mice. Although the small number of cells obtained can limit some of the applications for which the cells can be utilized, isolated coronary VSMCs can be used in a variety of well-established cell culture techniques and assays. Studies investigating VSMCs from genetically modified mice can provide further information about structure-function and signaling processes associated with vascular pathologies.

The purpose of this protocol is to demonstrate the isolation and culture techniques of murine primary vascular smooth muscle cells (VSMCs) from the coronary circulation. Once VSMCs have been isolated, they can be used for many standard culture techniques.

While the isolation and culture of vascular smooth muscle cells (VSMCs) from large vessels is well established, we sought to isolate and culture VSMCs ...

Murine Aortic Crush Injury: An Efficient In Vivo Model of Smooth Muscle Cell Proliferation and Endothelial Function

Arterial reconstruction, whether angioplasty or bypass surgery, involves iatrogenic trauma causing endothelial disruption and vascular smooth muscle cell (VSMC) proliferation. Common murine models study small vessels such as the carotid and femoral arteries. Herein we describe an in vivo system in which both VSMC proliferation and endothelial barrier function can be simultaneously assessed in a large vessel. We studied the infrarenal aortic response to injury in C57BL/6 mice. The aorta was injured from the left renal vein to the aortic bifurcation by 30 transmural crushes of 5-seconds duration with a cotton-tipped applicator. Morphological changes were assessed with conventional histology. Aorta wall thickness was measured from the luminal surface to the adventitia. EdU integration and counter staining with DAPI and alpha-actin was used to demonstrate VSMC proliferation. Activation of ERK1/2, a known moderator of intimal hyperplasia formation, was determined by Western Blot analysis. The effect of inflammation was determined by immunohistochemistry for B-cells, T-cells, and macrophages. En face sections of endothelium were visualized with scanning electron microscopy (SEM). Endothelial barrier function was determined with Evans Blue staining. Transmural injury resulted in aortic wall thickening. This injury induced VSMC proliferation, most prominently at 3 days after injury, and early activation of ERK1/2 and decreased p27kip1 expression. Injury did not result in increased B-cells, T-cells, or macrophages infiltration in the vessel wall. Injury caused partial endothelial cell denudation and loss of cell-cell contact. Injury resulted in a significant loss of endothelial barrier function, which returned to baseline after seven days. The murine transmural blunt aortic injury model provides an efficient system to simultaneously study both VSMC proliferation and endothelial barrier function in a large vessel.

Murine Aortic Crush Injury: An Efficient In Vivo Model of Smooth Muscle Cell Proliferation and Endothelial Function

Restenosis following cardiovascular procedures (bypass surgery, angioplasty, or stenting) is a significant problem reducing the durability of these procedures. An ideal therapy would inhibit smooth muscle cell (VSMC) proliferation while promoting regeneration of the endothelium. We describe a model for simultaneous assessment of VSMC proliferation and endothelial function in vivo.

Arterial reconstruction, whether angioplasty or bypass surgery, involves iatrogenic trauma causing endothelial disruption and vascular smooth muscle cell ...

Isolation and Culture of Primary Aortic Endothelial Cells from Miniature Pigs

Xenotransplantation is a promising way to resolve the shortage of human organs for patients with end-stage organ failure, and the pig is considered as a suitable organ source. Immune rejection and coagulation are two major hurdles for the success of xenotransplantation. Vascular endothelial cell (EC) injury and dysfunction are important for the development of the inflammation and coagulation responses in xenotransplantation. Thus, isolation of porcine aortic endothelial cells (pAECs) is necessary for investigating the immune rejection and coagulation responses. Here, we have developed a simple enzymatic approach for the isolation, characterization, and expansion of highly purified pAECs from miniature pigs. First, the miniature pig was anaesthetized with ketamine, and a length of aorta was excised. Second, the endothelial surface of aorta was exposed to 0.005% collagenase IV digestive solution for 15 min. Third, the endothelial surface of the aorta was scraped in only one direction with a cell scraper (&#60;10 times), and was not compressed during the process of scraping. Finally, the isolated pAECs of Day 3, and after passage 1 and passage 2, were identified by flow cytometry with an anti-CD31 antibody. The percentages of CD31-positive cells were 97.4% &#177; 1.2%, 94.4% &#177; 1.1%, and 92.4% &#177; 1.7% (mean &#177; SD), respectively. The concentration of Collagenase IV, the digestive time, the direction, and frequency and intensity of scraping are critical for decreasing fibroblast contamination and obtaining high-purity and a large number of ECs. In conclusion, our enzymatic method is a highly-effctive method for isolating ECs from the miniature pig aorta, and the cells can be expanded in vitro to investigate the immune and coagulation responses in xenotransplantation.

An effective enzymatic method for isolation of primary porcine aortic endothelial cells (pAECs) from miniature pigs is described. The isolated primary pAECs can be used to investigate the immune and coagulation response in xenotransplantation.

Xenotransplantation is a promising way to resolve the shortage of human organs for patients with end-stage organ failure, and the pig is considered as a ...

Measuring Proliferation of Vascular Smooth Muscle Cells Using Click Chemistry

The ability of a cell to proliferate is integral to the normal function of most cells, and dysregulation of proliferation is at the heart of many disease processes. For these reasons, measuring proliferation is a common tool used to assess cell function. Cell proliferation can be measured simply by counting; however, this is an indirect means of measuring proliferation. One common means of directly detecting cells preparing to divide is by incorporation of labeled nucleoside analogs. These include the radioactive nucleoside analog 3H-thymidine plus non-radioactive nucleoside analogs such as 5-bromo-2&#8217; deoxyuridine (BrdU) and 5-ethynyl-2&#8242;-deoxyuridine (EdU). Incorporation of EdU is detected by click chemistry, which has several advantages when compared to BrdU. In this report, we provide a protocol for measuring proliferation by the incorporation of EdU. This protocol includes options for various readouts, along with the advantages and disadvantages of each. We also discuss places where the protocol can be optimized or altered to meet the specific needs of the experiment planned. Finally, we touch on the ways that this basic protocol can be modified for measuring other cell metabolites.

Proliferation is a critical part of cellular function, and a common readout used to assess potential toxicity of new drugs. Measuring proliferation is, therefore, a frequently used assay in cell biology. Here we present a simple, versatile method of measuring proliferation that can be used in adherent and non-adherent cells.

The ability of a cell to proliferate is integral to the normal function of most cells, and dysregulation of proliferation is at the heart of many disease ...

Isolation of Mouse Interstitial Valve Cells to Study the Calcification of the Aortic Valve In Vitro

The calcification of aortic valve cells is the hallmark of aortic stenosis and is associated with valve cusp fibrosis. Valve interstitial cells (VICs) play an important role in the calcification process in aortic stenosis through the activation of their dedifferentiation program to osteoblast-like cells. Mouse VICs are a good in vitro tool for the elucidation of the signaling pathways driving the mineralization of the aortic valve cell. The method described herein, successfully used by these authors, explains how to obtain freshly isolated cells. A two-step collagenase procedure was performed with 1 mg/mL and 4.5 mg/mL. The first step is crucial to remove the endothelial cell layer and avoid any contamination. The second collagenase incubation is to facilitate the migration of VICs from the tissue to the plate. In addition, an immunofluorescence staining procedure for the phenotype characterization of the isolated mouse valve cells is discussed. Furthermore, the calcification assay was performed in vitro by using the calcium reagent measurement procedure and alizarin red staining. The use of mouse valve cell primary culture is essential for testing new pharmacological targets to inhibit cell mineralization in vitro.

Isolation of Mouse Interstitial Valve Cells to Study the Calcification of the Aortic Valve In Vitro

This article describes the isolation of mouse aortic valve cells by a two-step collagenase procedure. Isolated mouse valve cells are important for performing different assays, such as this in vitro calcification assay, and for investigating the molecular pathways leading to aortic valve mineralization.

The calcification of aortic valve cells is the hallmark of aortic stenosis and is associated with valve cusp fibrosis. Valve interstitial cells (VICs) ...