Name: processing of human cardiac tissue toward extracellular matrix self-assembling hydrogel for in vitro and in vivo applications
Uploaded: 2017-12-04T14:00:00
Description: Watch this Scientific Journal Video about Processing of Human Cardiac Tissue Toward Extracellular Matrix Self-assembling Hydrogel for In Vitro and In Vivo Applications at JoVE.com

The study protocol conforms to the ethical principles outlined in the Declaration of Helsinki. Patients provided informed consent for the use of the tissue for research purposes, and the process of tissue collection was approved by the Institutional Review Board and ethics committee of Charit&#233; - Universit&#228;tsmedizin Berlin (EA4/028/12).

The study protocol conforms to the ethical principles outlined in the Declaration of Helsinki and was approved by the institutional review board and ethics committee of Charit&#233; Medical University. All patients provided written, informed consent for use of heart tissue for experimental studies.
1. Preparation of Human Myocardium for Sectioning
<ol>
	<li>Obtain left ventricular myocardium (size varies depending on the type of surgery) directly from the operating room and transport in cold...

<ol>
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H., Romero-L&#243;pez, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-Dimensional+Adult+Cardiac+Extracellular+Matrix+Promotes+Maturation+of+Human+Induced+Pluripotent+Stem+Cell-Derived+Cardiomyocytes.">Three-Dimensional Adult Cardiac Extracellular Matrix Promotes Maturation of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes.</a> Tissue Engineering Part A. 22 (15-16), 1016-1025 (2016).</li><li>DeQuach, J. A., Mezzano, V., 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=Simple+and+High+Yielding+Method+for+Preparing+Tissue+Specific+Extracellular+Matrix+Coatings+for+Cell+Culture.">Simple and High Yielding Method for Preparing Tissue Specific Extracellular Matrix Coatings for Cell Culture.</a> PLoS ONE. 5 (9), e13039 (2010).</li><li>Saldin, L. T., Cramer, M. C., Velankar, S. S., White, L. J., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+matrix+hydrogels+from+decellularized+tissues:+Structure+and+function.">Extracellular matrix hydrogels from decellularized tissues: Structure and function.</a> Acta Biomaterialia. 49, 1-15 (2017).</li><li>Tukmachev, D., Forostyak, 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=Injectable+extracellular+matrix+hydrogels+as+scaffolds+for+spinal+cord+injury+repair.">Injectable extracellular matrix hydrogels as scaffolds for spinal cord injury repair.</a> Tissue Eng Part A. , (2016).</li><li>Freytes, D. O., Martin, J., Velankar, S. S., Lee, A. S., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+rheological+characterization+of+a+gel+form+of+the+porcine+urinary+bladder+matrix.">Preparation and rheological characterization of a gel form of the porcine urinary bladder matrix.</a> Biomaterials. 29 (11), 1630-1637 (2008).</li><li>Singelyn, J. M., Sundaramurthy, P., 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=Catheter-deliverable+hydrogel+derived+from+decellularized+ventricular+extracellular+matrix+increases+endogenous+cardiomyocytes+and+preserves+cardiac+function+post-myocardial+infarction.">Catheter-deliverable hydrogel derived from decellularized ventricular extracellular matrix increases endogenous cardiomyocytes and preserves cardiac function post-myocardial infarction.</a> Journal of the American College of Cardiology. 59 (8), 751-763 (2012).</li><li>Wainwright, J. M., Czajka, C. A., 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=Preparation+of+cardiac+extracellular+matrix+from+an+intact+porcine+heart.">Preparation of cardiac extracellular matrix from an intact porcine heart.</a> Tissue Eng Part C Methods. 16 (3), 525-532 (2010).</li><li>Ott, H. C., Matthiesen, T. 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=Perfusion-decellularized+matrix:+using+nature's+platform+to+engineer+a+bioartificial+heart.">Perfusion-decellularized matrix: using nature's platform to engineer a bioartificial heart.</a> Nature Medicine. 14, 213-221 (2008).</li><li>Oberwallner, B., Anic, B. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+cardiac+extracellular+matrix+supports+myocardial+lineage+commitment+of+pluripotent+stem+cells.">Human cardiac extracellular matrix supports myocardial lineage commitment of pluripotent stem cells.</a> Eur J Cardiothorac Surg. 47, 416-425 (2015).</li><li>Oberwallner, B., Brodarac, A., 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=Preparation+of+cardiac+extracellular+matrix+scaffolds+by+decellularization+of+human+myocardium.">Preparation of cardiac extracellular matrix scaffolds by decellularization of human myocardium.</a> Journal of Biomedical Materials Research Part A. 102 (9), 3263-3272 (2014).</li><li>Kappler, B., Anic, P., 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=The+cytoprotective+capacity+of+processed+human+cardiac+extracellular+matrix.">The cytoprotective capacity of processed human cardiac extracellular matrix.</a> Journal of Materials Science: Materials in Medicine. , (2016).</li><li>Bashey, R. I., Martinez-Hernandez, A., Jimenez, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation,+characterization,+and+localization+of+cardiac+collagen+type+VI.+Associations+with+other+extracellular+matrix+components.">Isolation, characterization, and localization of cardiac collagen type VI. Associations with other extracellular matrix components.</a> Circulation Research. 70 (5), (1992).</li><li>Wu, J., Ravikumar, P., Nguyen, K. T., Hsia, C. C. W., Hong, Y., Gorler, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lung+protection+by+inhalation+of+exogenous+solubilized+extracellular+matrix.">Lung protection by inhalation of exogenous solubilized extracellular matrix.</a> PLOS ONE. 12 (2), e0171165 (2017).</li><li>Chen, W. C. W., Wang, Z., 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=Decellularized+zebrafish+cardiac+extracellular+matrix+induces+mammalian+heart+regeneration.">Decellularized zebrafish cardiac extracellular matrix induces mammalian heart regeneration.</a> Science Advances. 2 (11), e1600844 (2016).</li><li>Godier-Furn&#233;mont, A. F. G., Martens, T. P., 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=Composite+scaffold+provides+a+cell+delivery+platform+for+cardiovascular+repair.">Composite scaffold provides a cell delivery platform for cardiovascular repair.</a> Proceedings of the National Academy of Sciences of the United States of America. 108 (19), 7974-7979 (2011).</li><li>Sarig, U., Sarig, H., 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=Natural+myocardial+ECM+patch+drives+cardiac+progenitor+based+restoration+even+after+scarring.">Natural myocardial ECM patch drives cardiac progenitor based restoration even after scarring.</a> Acta Biomaterialia. 44, 209-220 (2016).</li><li>Singelyn, J. M., DeQuach, J. A., Seif-Naraghi, S. B., Littlefield, R. B., Schup-Magoffin, P. J., Christman, K. 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When preparing human myocardial ECM, the goal is to achieve the following: removal of relevant immunogenic cellular material, preservation of ECM integrity and bioactivity, sterility, non-toxicity of the end-product, GMP-process compatibility, and suitability of the product for a given application in terms of handling. By combining our 3-step decellularization protocol with further processing into microparticles or self-assembling hydrogel, human cardiac ECM material is obtained that possesses specific biological activit...

The extracellular matrix (ECM) provides not only structural support but is also important for biologic cell and tissue function1. In the heart, the ECM participates in the regulation of pathophysiologic responses such as fibrosis, inflammation, angiogenesis, cardiomyocyte contractile function and viability, and resident progenitor cell fate. In addition to its primary components - fibrous glycoproteins, glycosaminoglycans, and proteoglycans - it contains a host of secreted growth factors, cytokines, and membranous vesicles containing nucleic acids and proteins2,3.
It has recently become clear that acellular ECM preparations are not only invaluable for studying cell-matrix interactions, but also for potential therapeutic cell-based applications. The importance of providing an adequate environment to therapeutic cell products or engineered tissues is now widely acknowledged. Attempts have been made to combine cell suspensions or active compounds with defined biopolymeric hydrogels4,5,6 or with protein cocktails secreted by murine sarcoma cells (i.e., Matrigel, Geltrex)7. However, the former have limited bioactivity, the latter are problematic in GMP-grade processes, and both lack the tissue-specific bioactivity of cardiac ECM (cECM)8,9,10,11,12,13.
Decellularization of the myocardium has previously been performed by perfusion of the whole heart via the coronary vasculature14,15. While this is possible in animal hearts, intact human hearts are rarely available. Therefore, an immersion process that allows for handling tissue samples obtained in the operating room was favored. Our &#34;3-step&#34; protocol contains 3 separate incubation steps namely lysis, solubilization, and DNA removal. It yields human myocardial ECM with largely preserved protein and glycosaminoglycan composition16,17. These cECM slices allow for in vitro studies of cell-matrix interactions but are poorly suited for potential human-scale therapeutic applications. The manufacturing process was then extended to produce either lyophilized cECM microparticles or a cECM hydrogel18.
This protocol allows for the decellularization of human myocardium obtained from surgical samples, preserving the major components of myocardial extracellular matrix (ECM) and their biologic activity. This protocol is recommended when human cardiac ECM with preserved tissue-specific bioactivity is required for experimental studies of cell-matrix interactions, or when a suitable environment is needed for cell-based myocardial regeneration approaches. In principle, it is also possible to adapt this protocol to GMP-grade conditions, so that the use of processed cECM should be feasible in future therapeutic applications.

<table>
	<tbody>
		<tr>
			<td>Balance</td>
			<td>DR Precisa, Dietikon, Switzerland</td>
			<td>Precisa XR 205SM</td>
			<td></td>
		</tr>
		<tr>
			<td>Blades Nr.10 Skalpell Nr.3</td>
			<td>InstrumenteNRW, Erftstadt, Germany</td>
			<td>SK-10-004</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell culture plates (6-well)</td>
			<td>Greiner, Frickenhausen, Germany</td>
			<td>657160</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryostat CM</td>
			<td>Leica, Wetzlar, Germany</td>
			<td>3050S</td>
			<td></td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Carl Roth, Karlsruhe, Germany</td>
			<td>8043.3</td>
			<td></td>
		</tr>
		<tr>
			<td>Eppendorf reaction tubes (1.5 or 2 ml)</td>
			<td>Greiner, Frickenhausen, Germany</td>
			<td>616201, 623201</td>
			<td></td>
		</tr>
		<tr>
			<td>Falcon 15ml, 50ml</td>
			<td>Greiner, Frickenhausen, Germany</td>
			<td>188271, 227270</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>Biochrome, Berlin, Germany</td>
			<td>S 0115</td>
			<td></td>
		</tr>
		<tr>
			<td>Freeze Dry System</td>
			<td>Labconco, Kansas City, USA</td>
			<td>7670520</td>
			<td></td>
		</tr>
		<tr>
			<td>Freezer (-80&#176;C)</td>
			<td>Thermo Scientific, Waltham, MA, USA</td>
			<td>Forma 900 Series</td>
			<td></td>
		</tr>
		<tr>
			<td>HCl</td>
			<td>Carl Roth, Karlsruhe, Germany</td>
			<td>281.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Microtome Blades Type 819</td>
			<td>Leica, Wetzlar, Germany</td>
			<td>14035838925</td>
			<td></td>
		</tr>
		<tr>
			<td>Minilys Homogeniser</td>
			<td>PEQLAB Biotechnologie GmbH, Erlangen, Germany</td>
			<td>91-PCSM</td>
			<td></td>
		</tr>
		<tr>
			<td>NaOH</td>
			<td>Carl Roth, Karlsruhe, Germany</td>
			<td>K021.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Nystatin</td>
			<td>PAN Biotech, Aidenbach, Germany</td>
			<td>P06-07800</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>Thermo Scientific, Waltham, MA, USA</td>
			<td>14190-094</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/streptomycin</td>
			<td>Life Technologies, Darmstadt, Germany</td>
			<td>15140122</td>
			<td></td>
		</tr>
		<tr>
			<td>Pepsin</td>
			<td>Sigma-Aldrich, Taufkirchen, Germany</td>
			<td>P6887-1G</td>
			<td></td>
		</tr>
		<tr>
			<td>Precellys Keramik-Kit 1.4 mm</td>
			<td>Peqlab Biotechnolgie, Erlangen, Germany</td>
			<td>91-PCS-CK14</td>
			<td></td>
		</tr>
		<tr>
			<td>Rotamax 120 Plate shaker</td>
			<td>Heidolph, Schwabach, Germany</td>
			<td>544-41200-00</td>
			<td></td>
		</tr>
		<tr>
			<td>SDS</td>
			<td>Carl Roth, Karlsruhe, Germany</td>
			<td>CN30.3</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereo microscope</td>
			<td>Leica, Wetzlar, Germany</td>
			<td>M125</td>
			<td></td>
		</tr>
		<tr>
			<td>Steriflip-GP, 0,22 &#181;m</td>
			<td>Merck Millipore, Darmstadt, Germany</td>
			<td>SCGP00525</td>
			<td></td>
		</tr>
		<tr>
			<td>Stuart analogue rocker &#38; roller mixers</td>
			<td>Sigma-Aldrich, Taufkirchen, Germany</td>
			<td>Z675113-1EA</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue Tek O.C.T compound</td>
			<td>Hartenstein, Wurzburg, Germany</td>
			<td>TTEK</td>
			<td></td>
		</tr>
		<tr>
			<td>Transfusion set 200&#181;m</td>
			<td>Sarstedt, N&#252;mbrecht, Germany</td>
			<td>798.200.500</td>
			<td></td>
		</tr>
		<tr>
			<td>TRIS</td>
			<td>Carl Roth, Karlsruhe, Germany</td>
			<td>5429.3</td>
			<td></td>
		</tr>
		<tr>
			<td>vedena Skalpellgriff Fig. 3, Standard, 125 mm</td>
			<td>Medical Highlights, Rohrdorf, Germany</td>
			<td>CV102-003</td>
			<td></td>
		</tr>
		<tr>
			<td>Vortex-Genie2</td>
			<td>Scientific Industry, New York, USA</td>
			<td>SI-0256</td>
			<td></td>
		</tr>
	</tbody>
</table>

processing of human cardiac tissue toward extracellular matrix self-assembling hydrogel for in vitro and in vivo applications

Acellular extracellular matrix preparations are useful for studying cell-matrix interactions and facilitate regenerative cell therapy applications. Several commercial extracellular matrix products are available as hydrogels or membranes, but these do not possess tissue-specific biological activity. Because perfusion decellularization is usually not possible with human heart tissue, we developed a 3-step immersion decellularization process. Human myocardial slices procured during surgery are first treated with detergent-free hyperosmolar lysis buffer, followed by incubation with the ionic detergent, sodium dodecyl sulfate, and the process is completed by exploiting the intrinsic DNase activity of fetal bovine serum. This technique results in cell-free sheets of cardiac extracellular matrix with largely preserved fibrous tissue architecture and biopolymer composition, which were shown to provide specific environmental cues to cardiac cell populations and pluripotent stem cells. Cardiac extracellular matrix sheets can then be further processed into a microparticle powder without further chemical modification, or, via short-term pepsin digestion, into a self-assembling cardiac extracellular matrix hydrogel with preserved bioactivity.

The 3-step protocol for decellularization of human myocardium presented here results in near-complete removal of cellular material, while preserving the key ECM components and the fibrillar structure of ECM. After decellularization, the gross removal of cells from the tissue is evident by the change in color (Figure 1A). Histological analysis with H&#38;E and Masson Trichrome stains revealed the complete absence of residual intact cells (...

Watch this Scientific Journal Video about Processing of Human Cardiac Tissue Toward Extracellular Matrix Self-assembling Hydrogel for In Vitro and In Vivo Applications at JoVE.com

Processing of Human Cardiac Tissue Toward Extracellular Matrix Self-assembling Hydrogel for In Vitro and In Vivo Applications

This protocol describes the complete decellularization of human myocardium while preserving its extracellular matrix components. Further processing of the extracellular matrix results in the production of microparticles and a cytoprotective self-assembling hydrogel.

Processing of Human Cardiac Tissue Toward Extracellular Matrix Self-assembling Hydrogel for In Vitro and In Vivo Applications

Acellular extracellular matrix preparations are useful for studying cell-matrix interactions and facilitate regenerative cell therapy applications. ...

The overall goal of this procedure is to process cardiac extracellular matrix to a hydrogel, which enables studying the effect of the matrix in various cell based assays. This method can help to answer key questions in the cardiac field, such as how extracellular matrix affects cell behavior. The main advantage of this technique is that it facilitates the use of the extracellular matrix to do large scale experiments in vitro or in vivo.The applications of this technique can be extended towards a therapy for myocardial infarction because the matrix can provide essential survival cues. To begin the experiment, use a sterile scalpel with a number ten blade, to remove fat tissue from a previously obtained left ventricular myocardium. Cut the myocardium in cubes approximately 1 by 1 by 1 cm, using a scalpel.Next, place the cubes into a sterile 50 mL tube. Store the tubes containing the cubes at 80 degrees celsius. Take the tube containing the prepared cubes out of the freezer and transport it on ice to the cryostat.Set the object and chamber temperature of the cryostat to 15 degrees celsius. Chill empty 50 mL tubes and stamps in the chamber. Add a layer of cryosection medium onto the cold stamp, and let it freeze until it is white and solid.Add a second layer of cryosection medium, and place a myocardium tube into the second layer. Make sure the cryosection medium and myocardium are completely frozen. Then, insert the stamp with frozen myocardium into the holder and tighten all the screws.Trim the surface of the tissue until an even sectioning surface is obtained. Section the frozen myocardium with automatic sectioning to guarantee uniform cut sections. Approximately 30 to 40 sections can be sliced from one cube.Place each slice, after sectioning, loosely in a pre-cooled 50 mL tube. Close the filled tubes and place them on ice. Transfer the frozen sections of all 50 mL tubes, into one sterile beaker.Add 50 mL of lysis solution per 50 mL tube containing myocardium slices. Next, shake the myocardium slices in a sterile beaker. Strain the liquid with the tissue slices through a coarse strainer.Then, transfer the tissue slices with a blunt tweezer to a new sterile beaker. Add 50 mL of 0.5%SDS in PBS per initial 50 mL tube of myocardium slices. Shake the beaker continuously for six hours at 100-150 rpm at room temperature.After shaking, strain the liquid with the tissues slices through a coarse strainer. Using blunt tweezer, transfer the tissues slices to a new sterile beaker and wash the slices three times with 50 mL of PBS. Next, wash the slices overnight in PBS, with 1%penicillin streptomycin and 1%nystatin.The next day, remove the washing solution, and add 25 mL of FBS preheated at 37 degrees celsius with 1%penicillin streptomycin and 1%nystatin, to the decellularized slices per initial 50 mL tube of myocardium slices. Incubate the slices for three hours at 37 degrees celsius to remove any remaining DNA from the matrix. Then, transfer the slices to a new sterile beaker and wash three times with 50 mL of PBS.Place the ECM slices loosely in a new sterile six well plate. Freeze the ECM at 80 degrees celsius, and lyophilize it for two days in a lyophilize. For the pulverization of the ECM slice, use milling tubes containing 1.4 mm ceramic beads.Fill the tubes loosely with lyophilized ECM, using sterile, blunt tweezers. Snap freeze the tubes in liquid nitrogen. Insert the frozen tubes into the milling machine and pulverize the ECM.Set the duration to 30 seconds, adjust the maximum speed, and start the device. After pulverization, take out the tubes, and snap freeze them again in liquid nitrogen. Wash the microparticles from the tubes, by adding 1 mL of ddH20 per tube, and shake for complete solubilization.Then, filter the heterogeneous solution through 200 micrometer mesh, into a 50 mL tube. Freeze the tube in liquid nitrogen. Replace the standard lid of tube, with a 0.22 micrometer filter to prevent the powder from flowing out of the tube.Insert the tube in the lyophilizer, and lyophilize again to remove the water from the wash step. Dissolve the previously prepared lyophilized human ECM powder in pepsin solution, to a final concentration of 10 mg per mL. Transfer the solution to 2 mL tubes with a volume of 1 mL per tube.Pipette the solution to mix thoroughly. Next, place the tubes in the shaker and shake at 1200 rpm for 48 hours at 27 degrees celsius. Take the tubes out of the shaker and place them on ice or a pre-cooled tube holder.Mix 1/9 of the volume of the ECM solution of cold 10X PBS, with 1/10 of a volume of ECM solution of cold 0.1 molar sodium hydroxide, in a pre-cooled tube and place it on ice to neutralize the digested ECM solution and inactivate the pepsin. Finally, add the ECM solution to the neutralization mixture and mix thoroughly through pipetting or vortexing. Quantitative assays for individual ECM components revealed a more complete DNA removal and better preservation of total collagen, elastin, and glycosominoglycans as compared with decellularization by SDS, alone.RT-PCR was used to quantify the expression of structural cardiomyocite proteins, early and late cardiomyogenic transcription factors, and endothelial cells surface marker genes in Murine ESC, undergoing spontaneous differentiation. Contact with cECM drives pluripotent stem cells, preferably toward a cardiomyocite like phenotype. Phase contrast light microscopy demonstrates that enzymatic digestion of the cECM for 48 hours, results in a more homogenized ECM solution.Live/dead staining of human cardiac fibroblasts on cECM hydrogel, shows increased viability. Both cECM microparticles and cECM hydrogel enhance the metabolic activity of contractile HL-1 cells, in ischemic conditions, as compared to cells in standard culture. Once mastered, this technique can be done within one week from tissue to hydrogel, if it's performed properly.After it's development, this technique paved the way for researchers in the field of cardiac regeneration, to explore the effects of cardiac extracellular matrix, in in vitro and in vivo, model systems.

processing-human-cardiac-tissue-toward-extracellular-matrix-self

Research

JoVE Journal

Developmental Biology

Characterization of Thymic Settling Progenitors in the Mouse Embryo Using In Vivo and In Vitro Assays

Characterizing thymic settling progenitors is important to understand the pre-thymic stages of T cell development, essential to devise strategies for T cell replacement in lymphopenic patients. We studied thymic settling progenitors from murine embryonic day 13 and 18 thymi by two complementary in vitro and in vivo techniques, both based on the &#8220;hanging drop&#8221; method. This method allowed colonizing irradiated fetal thymic lobes with E13 and/or E18 thymic progenitors distinguished by CD45 allotypic markers and thus following their progeny. Colonization with mixed populations allows analyzing cell autonomous differences in biologic properties of the progenitors while colonization with either population removes possible competitive selective pressures. The colonized thymic lobes can also be grafted in immunodeficient male recipient mice allowing the analysis of the mature T cell progeny in vivo, such as population dynamics of the peripheral immune system and colonization of different tissues and organs. Fetal thymic organ cultures revealed that E13 progenitors developed rapidly into all mature CD3+ cells and gave rise to the canonical &#947;&#948; T cell subset, known as dendritic epithelial T cells. In comparison, E18 progenitors have a delayed differentiation and were unable to generate dendritic epithelial T cells. The monitoring of peripheral blood of thymus-grafted CD3-/- mice further showed that E18 thymic settling progenitors generate, with time, larger numbers of mature T cells than their E13 counterparts, a feature that could not be appreciated in the short term fetal thymic organ cultures.

Characterization of Thymic Settling Progenitors in the Mouse Embryo Using In Vivo and In Vitro Assays

This article describes in vivo and in vitro methodology to characterize the thymic settling progenitors by the analysis of the kinetics of generation, phenotype and numbers of their T cell progeny.

Characterizing thymic settling progenitors is important to understand the pre-thymic stages of T cell development, essential to devise strategies for T ...

Analysis of Zebrafish Larvae Skeletal Muscle Integrity with Evans Blue Dye

The zebrafish model is an emerging system for the study of neuromuscular disorders. In the study of neuromuscular diseases, the integrity of the muscle membrane is a critical disease determinant. To date, numerous neuromuscular conditions display degenerating muscle fibers with abnormal membrane integrity; this is most commonly observed in muscular dystrophies. Evans Blue Dye (EBD) is a vital, cell permeable dye that is rapidly taken into degenerating, damaged, or apoptotic cells; in contrast, it is not taken up by cells with an intact membrane. EBD injection is commonly employed to ascertain muscle integrity in mouse models of neuromuscular diseases. However, such EBD experiments require muscle dissection and/or sectioning prior to analysis. In contrast, EBD uptake in zebrafish is visualized in live, intact preparations. Here, we demonstrate a simple and straightforward methodology for performing EBD injections and analysis in live zebrafish. In addition, we demonstrate a co-injection strategy to increase efficacy of EBD analysis. Overall, this video article provides an outline to perform EBD injection and characterization in zebrafish models of neuromuscular disease.

In this study, we describe a straightforward method to perform Evans Blue Dye (EBD) analysis on zebrafish larvae. This technique is a powerful tool for the characterization of skeletal muscle integrity and delineation of zebrafish models of muscular dystrophy, and is a valuable method for the development of novel therapeutics.

The zebrafish model is an emerging system for the study of neuromuscular disorders.  In the study of neuromuscular diseases, the integrity of the muscle ...

Isolation of Perivascular Multipotent Precursor Cell Populations from Human Cardiac Tissue

Multipotent mesenchymal stem/stromal cells (MSC) were conventionally isolated, through their plastic adherence, from primary tissue digests whilst their anatomical tissue location remained unclear. The recent discovery of defined perivascular and MSC cell marker expression by perivascular cells in multiple tissues by our group and other researchers has provided an opportunity to prospectively isolate and purify specific homogenous subpopulations of multipotent perivascular precursor cells. We have previously demonstrated the use of fluorescent activated cell sorting (FACS) to purify microvascular CD146+CD34- pericytes and vascular CD34+CD146- adventitial cells from human skeletal muscle. Herein we describe a method to simultaneously isolate these two perivascular cell subsets from human myocardium by FACS, based on the expression of a defined set of cell surface markers for positive and negative selections. This method thus makes available two specific subpopulations of multipotent cardiac MSC-like precursor cells for use in basic research and/or therapeutic investigations.

Human cardiac tissue harbours multipotent perivascular precursor cell populations that may be suitable for myocardial regeneration. The technique described here allows for the simultaneous isolation and purification of two multipotent stromal cell populations associated with native blood vessels, i.e. CD146+CD34- pericytes and CD34+CD146- adventitial cells, from the human myocardium.

Multipotent mesenchymal stem/stromal cells (MSC) were conventionally isolated, through their plastic adherence, from primary tissue digests whilst their ...

Live Imaging of Mouse Secondary Palate Fusion

The fusion of the secondary palatal shelves to form the intact secondary palate is a key process in mammalian development and its disruption can lead to cleft secondary palate, a common congenital anomaly in humans. Secondary palate fusion has been extensively studied leading to several proposed cellular mechanisms that may mediate this process. However, these studies have been mostly performed on fixed embryonic tissues at progressive timepoints during development or in fixed explant cultures analyzed at static timepoints. Static analysis is limited for the analysis of dynamic morphogenetic processes such a palate fusion and what types of dynamic cellular behaviors mediate palatal fusion is incompletely understood. Here we describe a protocol for live imaging of ex vivo secondary palate fusion in mouse embryos. To examine cellular behaviors of palate fusion, epithelial-specific Keratin14-cre was used to label palate epithelial cells in ROSA26-mTmGflox reporter embryos. To visualize filamentous actin, Lifeact-mRFPruby reporter mice were used. Live imaging of secondary palate fusion was performed by dissecting recently-adhered secondary palatal shelves of embryonic day (E) 14.5 stage embryos and culturing in agarose-containing media on a glass bottom dish to enable imaging with an inverted confocal microscope. Using this method, we have detected a variety of novel cellular behaviors during secondary palate fusion. An appreciation of how distinct cell behaviors are coordinated in space and time greatly contributes to our understanding of this dynamic morphogenetic process. This protocol can be applied to mutant mouse lines, or cultures treated with pharmacological inhibitors to further advance understanding of how secondary palate fusion is controlled.

Here, we present a protocol for live imaging of mouse secondary palate fusion using confocal microscopy. This protocol can be used in combination with a variety of fluorescent reporter mouse lines, and with pathway inhibitors for mechanistic insight. This protocol can be adapted for live imaging in other developmental systems.

The fusion of the secondary palatal shelves to form the intact secondary palate is a key process in mammalian development and its disruption can lead to ...

Immuno-fluorescent Labeling of Microtubules and Centrosomal Proteins in Ex Vivo Intestinal Tissue and 3D In Vitro Intestinal Organoids

The advent of 3D in vitro organoids that mimic the in vivo tissue architecture and morphogenesis has greatly advanced the ability to study key biological questions in cell and developmental biology. In addition, organoids together with recent technical advances in gene editing and viral gene delivery promises to advance medical research and development of new drugs for treatment of diseases. Organoids grown in vitro in basement matrix provide powerful model systems for studying the behavior and function of various proteins and are well suited for live-imaging of fluorescent-tagged proteins. However, establishing the expression and localization of the endogenous proteins in ex vivo tissue and in in vitro organoids is important to verify the behavior of the tagged proteins. To this end we have developed and modified tissue isolation, fixation, and immuno-labeling protocols for localization of microtubules, centrosomal, and associated proteins in ex vivo intestinal tissue and in in vitro intestinal organoids. The aim was for the fixative to preserve the 3D architecture of the organoids/tissue while also preserving antibody antigenicity and enabling good penetration and clearance of fixative and antibodies. Exposure to cold depolymerizes all but stable microtubules and this was a key factor when modifying the various protocols. We found that increasing the ethylenediaminetetraacetic acid (EDTA) concentration from 3 mM to 30 mM gave efficient detachment of villi and crypts in the small intestine while 3 mM EDTA was sufficient for colonic crypts. The developed formaldehyde/methanol fixation protocol gave very good structural preservation while also preserving antigenicity for effective labeling of microtubules, actin, and the end-binding (EB) proteins. It also worked for the centrosomal protein ninein although the methanol protocol worked more consistently. We further established that fixation and immuno-labeling of microtubules and associated proteins could be achieved with organoids isolated from or remaining within the basement matrix.

Immuno-fluorescent Labeling of Microtubules and Centrosomal Proteins in Ex Vivo Intestinal Tissue and 3D In Vitro Intestinal Organoids

We present protocols for isolation of intestinal 3D structures from in vivo tissue and in vitro basement matrix embedded organoids, and detail different fixation and staining protocols optimized for immuno-labeling of microtubule, centrosomal, and junctional proteins as well as cell markers including the stem cell protein Lgr5.

The advent of 3D in vitro organoids that mimic the in vivo tissue architecture and morphogenesis has greatly advanced the ability to study key biological ...

Cell Aggregation Assays to Evaluate the Binding of the Drosophila Notch with Trans-Ligands and its Inhibition by Cis-Ligands

Notch signaling is an evolutionarily conserved cell-cell communication system used broadly in animal development and adult maintenance. Interaction of the Notch receptor with ligands from neighboring cells induces activation of the signaling pathway (trans-activation), while interaction with ligands from the same cell inhibits signaling (cis-inhibition). Proper balance between trans-activation and cis-inhibition helps establish optimal levels of Notch signaling in some contexts during animal development. Because of the overlapping expression domains of Notch and its ligands in many cell types and the existence of feedback mechanisms, studying the effects of a given post-translational modification on trans- versus cis-interactions of Notch and its ligands in vivo is difficult. Here, we describe a protocol for using Drosophila S2 cells in cell-aggregation assays to assess the effects of knocking down a Notch pathway modifier on the binding of Notch to each ligand in trans and in cis. S2 cells stably or transiently transfected with a Notch-expressing vector are mixed with cells expressing each Notch ligand (S2-Delta or S2-Serrate). Trans-binding between the receptor and ligands results in the formation of heterotypic cell aggregates and is measured in terms of the number of aggregates per mL composed of &#62;6 cells. To examine the inhibitory effect of cis-ligands, S2 cells co-expressing Notch and each ligand are mixed with S2-Delta or S2-Serrate cells and the number of aggregates is quantified as described above. The relative decrease in the number of aggregates due to the presence of cis-ligands provides a measure of cis-ligand-mediated inhibition of trans-binding. These straightforward assays can provide semi-quantitative data on the effects of genetic or pharmacological manipulations on the binding of Notch to its ligands, and can help deciphering the molecular mechanisms underlying the in vivo effects of such manipulations on Notch signaling.

Cell Aggregation Assays to Evaluate the Binding of the Drosophila Notch with Trans-Ligands and its Inhibition by Cis-Ligands

Complexity of in vivo systems makes it difficult to distinguish between the activation and inhibition of Notch receptor by trans- and cis-ligands, respectively. Here, we present a protocol based on in vitro cell-aggregation assays for qualitative and semi-quantitative evaluation of the binding of Drosophila Notch to trans-ligands vs cis-ligands.

Notch signaling is an evolutionarily conserved cell-cell communication system used broadly in animal development and adult maintenance. Interaction of the ...

Isolation of Rat Adipose Tissue Mesenchymal Stem Cells for Differentiation into Insulin-producing Cells

Mesenchymal stem cells (MSCs)-especially those isolated from adipose tissue (Ad-MSCs)-have gained special attention as a renewable, abundant source of stem cells that does not pose any ethical concerns. However, current methods to isolate Ad-MSCs are not standardized and employ complicated protocols that require special equipment. We isolated Ad-MSCs from the epididymal fat of Sprague-Dawley rats using a simple, reproducible method. The isolated Ad-MSCs usually appear within 3 days post isolation, as adherent cells display fibroblastic morphology. Those cells reach 80% confluency within 1 week of isolation. Afterward, at passage 3-5 (P3-5), a full characterization was carried out for the isolated Ad-MSCs by immunophenotyping for characteristic MSC cluster of differentiation (CD) surface markers such as CD90, CD73, and CD105, as well as inducing differentiation of these cells down the osteogenic, adipogenic, and chondrogenic lineages. This, in turn, implies the multipotency of the isolated cells. Furthermore, we induced the differentiation of the isolated Ad-MSCs toward the insulin-producing cells (IPCs) lineage via a simple, relatively short protocol by incorporating high glucose Dulbecco&#39;s modified Eagle medium (HG-DMEM), &#946;-mercaptoethanol, nicotinamide, and exendin-4. IPCs differentiation was genetically assessed, firstly, via measuring the expression levels of specific &#946;-cell markers such as MafA, NKX6.1, Pdx-1, and Ins1, as well as dithizone staining for the generated IPCs. Secondly, the assessment was also carried out functionally by a glucose-stimulated insulin secretion (GSIS) assay. In conclusion, Ad-MSCs can be easily isolated, exhibiting all MSC characterization criteria, and they can indeed provide an abundant, renewable source of IPCs in the lab for diabetes research.

Adipose tissue-derived mesenchymal stem cells (Ad-MSCs) can be a potential source of MSCs that differentiate into insulin-producing cells (IPCs). In this protocol, we provide detailed steps for the isolation and characterization of rat epididymal Ad-MSCs, followed by a simple, short protocol for the generation of IPCs from the same rat Ad-MSCs.

Mesenchymal stem cells (MSCs)-especially those isolated from adipose tissue (Ad-MSCs)-have gained special attention as a renewable, abundant source of ...

Development of Organoids from Mouse Pituitary as In Vitro Model to Explore Pituitary Stem Cell Biology

The pituitary is the master endocrine gland regulating key physiological processes, including body growth, metabolism, sexual maturation, reproduction, and stress response. More than a decade ago, stem cells were identified in the pituitary gland. However, despite the application of transgenic in vivo approaches, their phenotype, biology, and role remain unclear. To tackle this enigma, a new and innovative organoid in vitro model is developed to deeply unravel pituitary stem cell biology. Organoids represent 3D cell structures that, under defined culture conditions, self-develop from a tissue's (epithelial) stem cells and recapitulate multiple hallmarks of those stem cells and their tissue. It is shown here that mouse pituitary-derived organoids develop from the gland's stem cells and faithfully recapitulate their in vivo phenotypic and functional characteristics. Among others, they reproduce the activation state of the stem cells as in vivo occurring in response to transgenically inflicted local damage. The organoids are long-term expandable while robustly retaining their stemness phenotype. The new research model is highly valuable to decipher the stem cells' phenotype and behavior during key conditions of pituitary remodeling, ranging from neonatal maturation to aging-associated fading, and from healthy to diseased glands. Here, a detailed protocol is presented to establish mouse pituitary-derived organoids, which provide a powerful tool to dive into the yet enigmatic world of pituitary stem cells.

Development of Organoids from Mouse Pituitary as In Vitro Model to Explore Pituitary Stem Cell Biology

The pituitary gland is the key regulator of the body's endocrine system. This article describes the development of organoids from the mouse pituitary as a novel 3D in vitro model to study the gland's stem cell population of which the biology and function remain poorly understood.

The pituitary is the master endocrine gland regulating key physiological processes, including body growth, metabolism, sexual maturation, reproduction, ...

Establishing Organoids from Human Tooth as a Powerful Tool Toward Mechanistic Research and Regenerative Therapy

Teeth are of key importance in life not only for food mastication and speech but also for psychological well-being. Knowledge on human tooth development and biology is scarce. In particular, not much is known about the tooth's epithelial stem cells and their function. We succeeded in developing a novel organoid model starting from human tooth tissue (i.e., dental follicle, isolated from extracted wisdom teeth). The organoids are robustly and long-term expandable and recapitulate the proposed human tooth epithelial stem cell compartment in terms of marker expression as well as functional activity. In particular, the organoids are capable to unfold an ameloblast differentiation process as occurring in vivo during amelogenesis. This unique organoid model will provide a powerful tool to study not only human tooth development but also dental pathology, and may pave the way toward tooth-regenerative therapy. Replacing lost teeth with a biological tooth based on this new organoid model could be an appealing alternative to the current standard implantation of synthetic materials.

We present a protocol to develop epithelial organoid cultures starting from human tooth. The organoids are robustly expandable and recapitulate the tooth's epithelial stem cells, including their ameloblast differentiation capacity. The unique organoid model provides a promising tool to study human dental (stem cell) biology with perspectives for tooth-regenerative approaches.

Teeth are of key importance in life not only for food mastication and speech but also for psychological well-being. Knowledge on human tooth development ...

Antibody Uptake Assay for Tracking Notch/Delta Endocytosis During the Asymmetric Division of Zebrafish Radial Glia Progenitors

Asymmetric cell division (ACD), which produces two daughter cells of different fates, is fundamental for generating cellular diversity. In the developing organs of both invertebrates and vertebrates, asymmetrically dividing progenitors generates a Notchhi self-renewing and a Notchlo differentiating daughter. In the embryonic zebrafish brain, radial glia progenitors (RGPs)-the principal vertebrate neural stem cells-mostly undergo ACD to give birth to one RGP and one differentiating neuron. The optical clarity and easy accessibility of zebrafish embryos make them ideal for in vivo time-lapse imaging to directly visualize how and when the asymmetry of Notch signaling is established during ACD. Recent studies have shown that dynamic endocytosis of the Notch ligand DeltaD plays a crucial role in cell fate determination during ACD, and the process is regulated by the evolutionarily conserved polarity regulator Par-3 (also known as Pard3) and the dynein motor complex. To visualize the in vivo trafficking patterns of Notch signaling endosomes in mitotic RGPs, we have developed this antibody uptake assay. Using the assay, we have uncovered the dynamicity of DeltaD-containing endosomes during RGP division.

This work develops an antibody uptake assay for imaging intra-lineage Notch/DeltaD signaling in dividing radial glia progenitors of the embryonic zebrafish brain.

Asymmetric cell division (ACD), which produces two daughter cells of different fates, is fundamental for generating cellular diversity. In the developing ...