We would like to acknowledge all the lab members in the Division of Regenerative Medicine at the Jichi Medical University for the helpful discussion and technical assistance. This study was supported by the grants from the Japan Agency for Medical Research and Development (AMED; JP18bm0704012&#160;and JP20bm0804018), the Japan Society for the Promotion of Science (JSPS; JP19KK0219), and the Japanese Circulation Society (the Grant for Basic Research) to H.U.

<ol>
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H.U. has filed a patent related to this manuscript.

PSC-CMs have great potential to be utilized as an&#160;in vitro platform to model heart disease and to test the effects of drugs. Nevertheless, an accurate, unified method to assess PSC-CMs functions must first be established. Most of functional tests work with PSC-CMs, e.g., electrophysiology, calcium transient, and metabolism26, and one of the first patient-derived PSC-CM studies was about long-QT syndrome27. However, contractility, one of the most important func...

Cardiovascular diseases are the leading cause of mortality worldwide1 and cardiomyopathy represents the third cause of cardiac-related deaths2.Cardiomyopathy is a collective group of diseases that affect cardiac muscles. The recent developments of induced pluripotent stem (iPS) cells and the directed-differentiation of iPS cells toward cardiomyocytes (PSC-CMs) have opened the door for studying cardiomyocytes with patient genome as an in vitro model of cardiomyopathy. These cells can be used to understand the pathophysiology of cardiac diseases, to elucidate their molecular mechanisms, and to test different therapeutic candidates3. There is a tremendous amount of interest, thus, patient-derived iPS cells have been generated (e.g., hypertrophic cardiomyopathy [HCM]4,5, arrhythmogenic right ventricular cardiomyopathy [ARVC]6, dilated cardiomyopathy [DCM]7, and mitochondrial-related cardiomyopathies8,9). Because one of the characteristics of cardiomyopathy is the dysfunction and disruption of sarcomeres, a valid tool that uniformly measures sarcomere function is needed.
Sarcomere shortening is the most widely used technique to assess sarcomere function and the contractility of adult cardiomyocytes derived from animal models and humans. To perform sarcomere shortening, well-developed sarcomeres that are visible under phase-contrast are required. However, PSC-CMs cultured in vitro display underdeveloped and disorganized sarcomeres and, therefore, are unable to be used to properly measure sarcomere shortening10. This difficulty to properly assess the contractility of PSC-CMs hinders their usage as a platform to assess cardiac functions in vitro. To assess PSC-CMs contractility indirectly, atomic force microscopy, micro-post arrays, traction force microscopy, and impedance measurements have been used to measure the effects of the motion exerted by these cells on their surroundings11,12,13. More sophisticated and less invasive video-microscopy recordings of actual cellular motion (e.g., SI8000 from SONY) can be used to alternatively assess their contractility, however, this method does not directly measure sarcomere motion or force generation kinetics14.
To directly measure sarcomere motion in PSC-CMs, new approaches, such as fluorescent-tagging to sarcomere protein, are emerging. For example, Lifeact is used to label filamentous actin (F-actin) to measure sarcomere motion15,16. Genetically modified iPS cells are another option for tagging sarcomere proteins (e.g., &#945;-actinin [ACTN2] and Myomesin-2 [MYOM2]) by fluorescent protein17,18,19.
In this paper, we describe how to perform time-lapse imaging for measuring sarcomere shortening using Myom2-TagRFP (mouse embryonic stem [ES] cells) and ACTN2-mCherry (human iPS cells). We also show that a patterned culture facilitates sarcomere alignment. In addition, we describe an alternative method of sarcomere labeling, using adeno-associated viruses (AAVs), which can be widely applied to patient-derived iPS cells.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1-Thioglycerol</td>
			<td>Sigma-Aldrich</td>
			<td>M6145-25</td>
			<td></td>
		</tr>
		<tr>
			<td>2-Mercaptoethanol (55mM)</td>
			<td>Thermo Fisher Scientific</td>
			<td>21985-023</td>
			<td></td>
		</tr>
		<tr>
			<td>2-methacryloyloxyethyl phosphorylcholine (MPC) polymer,</td>
			<td>NOF Corp.</td>
			<td>LIPIDURE-CM5206</td>
			<td></td>
		</tr>
		<tr>
			<td>2-Propanol</td>
			<td>Fujifilm wako</td>
			<td>166-04836</td>
			<td></td>
		</tr>
		<tr>
			<td>35-mm imaging dish with a polymer coverslip (&#181;-Dish 35 mm, high)</td>
			<td>ibidi</td>
			<td>81156</td>
			<td></td>
		</tr>
		<tr>
			<td>AAVproR Helper Free System (AAV6) 
			(vectors; pHelper, pRC6, pAAV-CMV-Vector)</td>
			<td>Takara</td>
			<td>6651</td>
			<td></td>
		</tr>
		<tr>
			<td>ACTN2-mCherry (AR12, AR21) hiPSCs</td>
			<td>N.A.</td>
			<td></td>
			<td>We inserted IRES-puromycin resistant casette to 3&#39; UTR of TNNT2 locus and mCherry around the stop codon of ACTN2 in 610B1 hiPSC line, following a method describe elsewhere (Anzai, Methods Mol Biol, in press)</td>
		</tr>
		<tr>
			<td>B-27 Supplement (50X), serum free</td>
			<td>Thermo Fisher Scientific</td>
			<td>17504-044</td>
			<td></td>
		</tr>
		<tr>
			<td>B-27 Supplement, minus insulin</td>
			<td>Thermo Fisher Scientific</td>
			<td>A18956-01</td>
			<td></td>
		</tr>
		<tr>
			<td>B27 supplement (50X), minus Vitamin A</td>
			<td>Thermo Fisher Scientific</td>
			<td>12587-010</td>
			<td></td>
		</tr>
		<tr>
			<td>Benzonase (25 U/&#181;L)</td>
			<td>Merck Millipore</td>
			<td>70746</td>
			<td></td>
		</tr>
		<tr>
			<td>Blasticidin S Hydrochloride</td>
			<td>Fujifilm wako</td>
			<td>029-18701</td>
			<td></td>
		</tr>
		<tr>
			<td>BMP-4, Human, Recombinant,</td>
			<td>R&#38;D Systems, Inc.</td>
			<td>314-BP-010</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin</td>
			<td>Sigma-Aldrich</td>
			<td>A4503-100g</td>
			<td></td>
		</tr>
		<tr>
			<td>C59, Wnt Antagonist (WntC59)</td>
			<td>abcam</td>
			<td>ab142216</td>
			<td></td>
		</tr>
		<tr>
			<td>CAD drawing software,</td>
			<td>Robert McNeel and Associates, WA, USA</td>
			<td>Rhinoceros 6.0</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifugal ultrafiltration unit (100k MWCO), Vivaspin-20</td>
			<td>Sartorius</td>
			<td>VS2042</td>
			<td></td>
		</tr>
		<tr>
			<td>CHIR99021</td>
			<td>Cayman</td>
			<td>13122</td>
			<td></td>
		</tr>
		<tr>
			<td>Chromium etchant</td>
			<td>Nihon Kagaku Sangyo Co., Ltd., Japan</td>
			<td>N14B</td>
			<td></td>
		</tr>
		<tr>
			<td>Chromium mask coated with AZP1350</td>
			<td>Clean Surface Technology Co., Japan</td>
			<td>CBL2506Bu-AZP</td>
			<td></td>
		</tr>
		<tr>
			<td>Dr. GenTLE Precipitation Carrier (20mg/mL Glycogen, 3 M Sodium Acetate (pH 5.2))</td>
			<td>Takara</td>
			<td>9094</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#8217;s Modified Eagle&#8217;s Medium (DMEM) - high glucose</td>
			<td>Sigma-Aldrich</td>
			<td>D6429-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#8217;s Modified Eagle&#8217;s Medium (DMEM) - high glucose, without sodium pyruvate</td>
			<td>Sigma-Aldrich</td>
			<td>D5796</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol (99.5)</td>
			<td>Fujifilm wako</td>
			<td>057-00456</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Moregate</td>
			<td>59301104</td>
			<td></td>
		</tr>
		<tr>
			<td>FGF-10, Human, Recombinant,</td>
			<td>R&#38;D Systems, Inc.</td>
			<td>345-FG-025</td>
			<td></td>
		</tr>
		<tr>
			<td>Fibroblast Growth Factor(basic), human, recombinant</td>
			<td>Fujifilm wako</td>
			<td>060-04543</td>
			<td></td>
		</tr>
		<tr>
			<td>Gelatin from porcine skin powder</td>
			<td>Sigma-Aldrich</td>
			<td>G1890-100g</td>
			<td></td>
		</tr>
		<tr>
			<td>Glasgow Minimum Essential Medium (GMEM)</td>
			<td>Sigma-Aldrich</td>
			<td>G5154-500</td>
			<td></td>
		</tr>
		<tr>
			<td>GLASS BOTTOM culture plates</td>
			<td>MatTek</td>
			<td>P24G-1.5-13-F/H</td>
			<td></td>
		</tr>
		<tr>
			<td>Ham&#8217;s F-12</td>
			<td>Thermo Fisher Scientific</td>
			<td>11765-062</td>
			<td></td>
		</tr>
		<tr>
			<td>Iscove&#39;s Modified Dulbecco&#39;s Medium (IMDM)</td>
			<td>Thermo Fisher Scientific</td>
			<td>12440-061</td>
			<td></td>
		</tr>
		<tr>
			<td>L-alanine-L-glutamine (GlutaMAX Supplement, 200mM)</td>
			<td>Thermo Fisher Scientific</td>
			<td>35050-061</td>
			<td></td>
		</tr>
		<tr>
			<td>L(+)-Ascorbic Acid Sodium Salt</td>
			<td>Fujifilm wako</td>
			<td>196-01252</td>
			<td></td>
		</tr>
		<tr>
			<td>Laminin-511 E8 fragment (LN511-E8, iMatrix-511)</td>
			<td>Nippi</td>
			<td>892012</td>
			<td></td>
		</tr>
		<tr>
			<td>Mask aligner</td>
			<td>Union Optical Co., Ltd., Japan</td>
			<td>PEM-800</td>
			<td></td>
		</tr>
		<tr>
			<td>Maskless lithography tool</td>
			<td>NanoSystem Solutions, Inc., Japan</td>
			<td>D-Light DL-1000</td>
			<td></td>
		</tr>
		<tr>
			<td>MEM Non-Essential Amino Acids Solution (100X)</td>
			<td>Thermo Fisher Scientific</td>
			<td>11140-050</td>
			<td></td>
		</tr>
		<tr>
			<td>Millex-HV Syringe Filter Unit, 0.45 &#181;m, PVDF (0.45-&#181;m filter)</td>
			<td>Merck Millipore</td>
			<td>SLHVR33RS</td>
			<td></td>
		</tr>
		<tr>
			<td>Myom2-RFP (SMM18)</td>
			<td>N.A.</td>
			<td></td>
			<td>Developed in our previous paper (Chanthra, Sci Rep, 2020)</td>
		</tr>
		<tr>
			<td>N-2 Supplement (100X)</td>
			<td>Thermo Fisher Scientific</td>
			<td>17502-048</td>
			<td></td>
		</tr>
		<tr>
			<td>ORCA-Flash4.0 V3 digital CMOS camera</td>
			<td>Hamamatsu</td>
			<td>C13440-20CU</td>
			<td></td>
		</tr>
		<tr>
			<td>PD0325901</td>
			<td>Stemgent</td>
			<td>04-0006-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin (10,000 U/mL)</td>
			<td>Thermo Fisher Scientific</td>
			<td>15140-122</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dish</td>
			<td>Sansei medical co. Ltd</td>
			<td>01-004</td>
			<td></td>
		</tr>
		<tr>
			<td>Phenol/Chloroform/Isoamyl alcohol (25:24:1)</td>
			<td>Nippon Gene</td>
			<td>311-90151</td>
			<td></td>
		</tr>
		<tr>
			<td>Polydimethylsiloxane (PDMS) elastomer</td>
			<td>Dow Corning Corp., MI, USA</td>
			<td>SILPOT 184</td>
			<td></td>
		</tr>
		<tr>
			<td>polyethylenimine MAX (MW. 40,000)</td>
			<td>Polyscience</td>
			<td>24765-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Positive photoresist developer</td>
			<td>Tokyo Ohka Kogyo Co., Ltd., Japan</td>
			<td>NMD-3</td>
			<td></td>
		</tr>
		<tr>
			<td>PowerUp SYBR Green Master Mix</td>
			<td>Thermo Fisher Scientific</td>
			<td>A25742</td>
			<td></td>
		</tr>
		<tr>
			<td>Proteinase K</td>
			<td>Takara</td>
			<td>9034</td>
			<td></td>
		</tr>
		<tr>
			<td>Puromycin Dihydrochloride</td>
			<td>Fujifilm wako</td>
			<td>166-23153</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Human/Mouse/Rat Activin A Protein</td>
			<td>R&#38;D Systems, Inc.</td>
			<td>338-AC-050</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant trypsin-like protease (rTrypsin; TrypLE express)</td>
			<td>Thermo Fisher Scientific</td>
			<td>12604-039</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI1640 Medium</td>
			<td>Thermo Fisher Scientific</td>
			<td>11875-119</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicon wafer</td>
			<td>Matsuzaki Seisakusyo Co., Ltd., Japan</td>
			<td>N.A.</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Pyruvate (100 mM)</td>
			<td>Thermo Fisher Scientific</td>
			<td>11360-070</td>
			<td></td>
		</tr>
		<tr>
			<td>Spin-coater</td>
			<td>Mikasa Co., Ltd., Japan</td>
			<td>MS-A100</td>
			<td></td>
		</tr>
		<tr>
			<td>Spininng confocal microscopy</td>
			<td>Oxford Instruments</td>
			<td>Andor Dragonfly Spinning Disk System</td>
			<td></td>
		</tr>
		<tr>
			<td>StemSure LIF, Mouse, recombinant, Solution (10^6U)</td>
			<td>Fujifilm wako</td>
			<td>195-16053</td>
			<td></td>
		</tr>
		<tr>
			<td>SU-8 3010</td>
			<td>Kayaku Advanced Materials, Inc., MA, USA</td>
			<td>SU-8 3010</td>
			<td></td>
		</tr>
		<tr>
			<td>SU-8 developer</td>
			<td>Kayaku Advanced Materials, Inc., MA, USA</td>
			<td>SU-8 developer</td>
			<td></td>
		</tr>
		<tr>
			<td>Tris-EDTA</td>
			<td>Nippon Gene</td>
			<td>314-90021</td>
			<td></td>
		</tr>
		<tr>
			<td>Vascular Endothelial Growth Factor-A165(VEGF), Human, recombinant</td>
			<td>Fujifilm wako</td>
			<td>226-01781</td>
			<td></td>
		</tr>
	</tbody>
</table>

sarcomere shortening of pluripotent stem cell-derived cardiomyocytes using fluorescent-tagged sarcomere proteins.

Pluripotent stem cell-derived cardiomyocytes (PSC-CMs) can be produced from both embryonic and induced pluripotent stem (ES/iPS) cells. These cells provide promising sources for cardiac disease modeling. For cardiomyopathies, sarcomere shortening is one of the standard physiological assessments that are used with adult cardiomyocytes to examine their disease phenotypes. However, the available methods are not appropriate to assess the contractility of PSC-CMs, as these cells have underdeveloped sarcomeres that are invisible under phase-contrast microscopy. To address this issue and to perform sarcomere shortening with PSC-CMs, fluorescent-tagged sarcomere proteins and fluorescent live-imaging were used. Thin Z-lines and an M-line reside at both ends and the center of a sarcomere, respectively. Z-line proteins &#8212;&#160;&#945;-Actinin (ACTN2), Telethonin (TCAP), and actin-associated LIM protein (PDLIM3) &#8212; and one M-line protein &#8212; Myomesin-2 (Myom2) &#8212;&#160;were tagged with fluorescent proteins. These tagged proteins can be expressed from endogenous alleles as knock-ins or from adeno-associated viruses (AAVs). Here, we introduce the methods to differentiate mouse and human pluripotent stem cells to cardiomyocytes, to produce AAVs, and to perform and analyze live-imaging. We also describe the methods for producing polydimethylsiloxane (PDMS) stamps for a patterned culture of PSC-CMs, which facilitates the analysis of sarcomere shortening with fluorescent-tagged proteins. To assess sarcomere shortening, time-lapse images of the beating cells were recorded at a high framerate (50-100 frames per second) under electrical stimulation (0.5-1 Hz). To analyze sarcomere length over the course of cell contraction, the recorded time-lapse images were subjected to SarcOptiM, a plug-in for ImageJ/Fiji. Our strategy provides a simple platform for investigating cardiac disease phenotypes in PSC-CMs.

Measuring sarcomere shortening using knock-in PSC-CMs reporter lines. Sarcomere-labeled PSC-CMs were used to measure sarcomere shortening. The lines express Myom2-RFP and ACTN2-mCherry from endogenous loci. TagRFP was inserted to Myom2, coding M-proteins that localize to the M-line, while mCherry was knocked-in to ACTN2, coding &#945;-Actinin, which localizes to the Z-line18,25. Time-lapse images...

Watch this Scientific Journal Video about Sarcomere Shortening of Pluripotent Stem Cell-Derived Cardiomyocytes using Fluorescent-Tagged Sarcomere Proteins. at JoVE.com

Sarcomere Shortening of Pluripotent Stem Cell-Derived Cardiomyocytes using Fluorescent-Tagged Sarcomere Proteins.

This method can be used to examine sarcomere shortening using pluripotent stem cell-derived cardiomyocytes with fluorescent-tagged sarcomere proteins.

Pluripotent stem cell-derived cardiomyocytes (PSC-CMs) can be produced from both embryonic and induced pluripotent stem (ES/iPS) cells. These cells ...

sarcomere-shortening-pluripotent-stem-cell-derived-cardiomyocytes

Research

JoVE Journal

Medicine

4.3K Views.  Jichi Medical University. This method can be used to examine sarcomere shortening using pluripotent stem cell-derived cardiomyocytes with fluorescent-tagged sarcomere proteins.

Video: Sarcomere Shortening of Pluripotent Stem Cell-Derived Cardiomyocytes using Fluorescent-Tagged Sarcomere Proteins.

Generation of Induced Pluripotent Stem Cells from Muscular Dystrophy Patients: Efficient Integration-free Reprogramming of Urine Derived Cells

Dystrophic cardiomyopathy is a poorly understood consequence of muscular dystrophy. Generating induced Pluripotent Stem Cells (iPSCs) from patients with muscular dystrophy is an invaluable cellular source for in&#160;vitro disease model systems and can be used for drug screening studies. Patient-derived urine cells have been used in successful reprogramming into induced pluripotent stem cells in order to model dystrophic cardiomyopathy1. Addressing the safety concerns of integrating vector systems, we present a protocol using a non-integrating Sendai virus vector for transduction of Yamanaka factors into urine cells collected from patients with muscular dystrophy. This protocol generates fully reprogrammed clones within 2&#8211;3 weeks. The pluripotent cells are vector-free by passage-13. These dystrophic iPSCs can be differentiated into cardiomyocytes and used either to study disease mechanisms or for drug screening.

This protocol entails detailed procedures for isolation of urine derived cells from muscular dystrophy patients; their efficient and rapid reprogramming through Sendai virus transduction.

Dystrophic cardiomyopathy is a poorly understood consequence of muscular dystrophy. Generating induced Pluripotent Stem Cells (iPSCs) from patients with ...

Rapid and Efficient Generation of Recombinant Human Pluripotent Stem Cells by Recombinase-mediated Cassette Exchange in the AAVS1 Locus

Even with the revolution of gene-targeting technologies led by CRISPR-Cas9, genetic modification of human pluripotent stem cells&#160;(hPSCs)&#160;is still time consuming. Comparative studies that use recombinant lines with transgenes integrated into safe harbor loci could benefit from approaches that use site-specific targeted recombinases, like Cre or FLPe, which are more rapid and less prone to off-target effects. Such methods have been described, although they do not significantly outperform gene targeting in most aspects. Using Zinc-finger nucleases, we previously created a master cell line in the AAVS1 locus of hPSCs&#160;that contains a GFP-Hygromycin-tk expressing cassette, flanked by heterotypic FRT sequences. Here, we describe the procedures to perform FLPe recombinase-mediated cassette exchange (RMCE) using this line. The master cell line is transfected with a RMCE donor vector, which contains a promoterless Puromycin resistance, and with FLPe recombinase. Application of both a positive (Puromycin) and negative (FIAU) selection program leads to the selection of RMCE without random integrations. RMCE generates fully characterized pluripotent polyclonal transgenic lines in 15 d&#160;with 100% efficiency. Despite the recently described limitations of the AAVS1 locus, the ease of the system paves the way for hPSC transgenesis in isogenic settings, is necessary for comparative studies, and enables semi-high-throughput genetic screens for gain/loss of function analysis that would otherwise be highly time consuming.

Rapid and Efficient Generation of Recombinant Human Pluripotent Stem Cells by Recombinase-mediated Cassette Exchange in the AAVS1 Locus

Here we report a rapid and efficient gene editing method based on RMCE in the AAVS1 locus of human Pluripotent Stem Cells (hPSCs) that improves upon previously described systems. Using this technique, isogenic lines can be rapidly and reliably generated for proper comparative studies, facilitating transgenesis-mediated research with hPSCs.

Even with the revolution of gene-targeting technologies led by CRISPR-Cas9, genetic modification of human pluripotent stem cells&#160;(hPSCs)&#160;is ...

Isolation and Cultivation of Adult Rat Cardiomyocytes

In an intact heart, adjacent cells influence adult cardiomyocytes. With the method of isolation and cultivation of adult cardiomyocytes, a precise investigation of the behavior of these cells under specific treatments and environments is possible. This manuscript presents a protocol for successful isolation and cultivation of adult rat ventricular cardiomyocytes (ARVC).
The rat is sacrificed by cervical dislocation under deep anesthesia. Then, the heart is extracted and the aorta is uncovered. Subsequently, perfusion on the Langendorff perfusion system with calcium depletion and collagenase treatment is performed. Afterwards, ventricular tissue gets minced, re-circulated, and filtered, followed by three centrifugation steps with gradual addition of CaCl2 until physiological calcium concentration is reached. ARVC are plated on cell culture dishes. After refreshing the cell culture medium, ARVC can be cultivated for up to six days without changing the serum-containing culture medium. Isolation of ARVC is a calcium sensitive process. Small changes in the intracellular calcium concentration cause a decrease in the quality and viability of the isolated cells.
Freshly isolated ARVC are rod shaped. Within the first days of cultivation they lose the rod-shaped morphology and form pseudopodia-like structures (spreading). During this morphological formation ARVC initially degrade their contractile elements followed by a reformation through actin stress fibers and de novo sarcomerogenesis. After one week of cultivation, most ARVC show a widespread appearance with a clearly detectable cross striation. This process is sensitive to intracellular calcium concentration, as treatment with ionomycin attenuates spreading. Key markers in this process of de- and re-differentiation are &#946;-myosin heavy chain (&#946;-MHC), oncostatin M (OSM), and swiprosin-1 (EFHD2). Recent studies have suggested that cardiac re- and de-differentiation occurring under culture conditions mimics features seen in vivo during cardiac remodeling. Therefore, isolation and cultivation of ARVC play a key role in understanding the biology of cardiomyocytes.

Here, we present a protocol for the isolation and cultivation of adult rat ventricular cardiomyocytes (ARVC). Isolated ARVC can be used for short and long-term cultivation. The isolation and cultivation of ARVC can play a key role in developing new treatment regimens for cardiac diseases.

In an intact heart, adjacent cells influence adult cardiomyocytes. With the method of isolation and cultivation of adult cardiomyocytes, a precise ...

Targeted and Selective Treatment of Pluripotent Stem Cell-derived Teratomas Using External Beam Radiation in a Small-animal Model

The growing number of victims of &#34;stem cell tourism,&#34; the unregulated transplantation of stem cells worldwide, has raised concerns about the safety of stem cell transplantation. Although the transplantation of differentiated rather than undifferentiated cells is common practice, teratomas can still arise from the presence of residual undifferentiated stem cells at the time of transplant or from spontaneous mutations in differentiated cells. Because stem cell therapies are often delivered into anatomically sensitive sites, even small tumors can be clinically devastating, resulting in blindness, paralysis, cognitive abnormalities, and cardiovascular dysfunction. Surgical access to these sites may also be limited, leaving patients with few therapeutic options. Controlling stem cell misbehavior is, therefore, critical for the clinical translation of stem cell therapy.
External beam radiation offers an effective means of delivering targeted therapy to decrease the teratoma burden while minimizing injury to surrounding organs. Additionally, this method avoids genetic manipulation or viral transduction of stem cells-which are associated with additional clinical safety and efficacy concerns. Here, we describe a protocol to create pluripotent stem cell-derived teratomas in mice and to apply external beam radiation therapy to selectively ablate these tumors in vivo.

Research on treatment strategies for pluripotent stem cell-derived teratomas is important for the clinical translation of stem cell therapy. Here, we describe a protocol to, first, generate stem cell-derived teratomas in mice and, then, to selectively target and treat these tumors in vivo using a small-animal irradiator.

The growing number of victims of &#34;stem cell tourism,&#34; the unregulated transplantation of stem cells worldwide, has raised concerns about the ...

In Vitro Assessment of Cardiac Function Using Skinned Cardiomyocytes

In this article, we describe the steps required to isolate a single permeabilized (&#34;skinned&#34;) cardiomyocyte and attach it to a force-measuring apparatus and a motor to perform functional studies. These studies will allow measurement of cardiomyocyte stiffness (passive force) and its activation with different calcium (Ca2+)-containing solutions to determine, amongst others: maximum force development, myofilament Ca2+-sensitivity (pCa50), cooperativity (nHill) and the rate of force redevelopment (ktr). This method also enables determination of the effects of drugs acting directly on myofilaments and of the expression of exogenous recombinant proteins on both active and passive properties of cardiomyocytes. Clinically, skinned cardiomyocyte studies highlight the pathophysiology of many myocardial diseases and allow in vitro assessment of the impact of therapeutic interventions targeting the myofilaments. Altogether, this technique enables the clarification of cardiac pathophysiology by investigating correlations between in vitro and in vivo parameters in animal models and human tissue obtained during open heart or transplant surgery.

This protocol aims to describe step-by-step the technique of extraction and assessment of cardiac function using skinned cardiomyocytes. This methodology allows measurement and acutemodulation of myofilament function using small frozen biopsies that can be collected from different cardiac locations, from mice to men.

In this article, we describe the steps required to isolate a single permeabilized (&#34;skinned&#34;) cardiomyocyte and attach it to a force-measuring ...

Model of Ischemic Heart Disease and Video-Based Comparison of Cardiomyocyte Contraction Using hiPSC-Derived Cardiomyocytes

Ischemic heart disease is a significant cause of death worldwide. It has therefore been the subject of a tremendous amount of research, often with small-animal models such as rodents. However, the physiology of the human heart differs significantly from that of the rodent heart, underscoring the need for clinically relevant models to study heart disease. Here, we present a protocol to model ischemic heart disease using cardiomyocytes differentiated from human induced pluripotent stem cells (hiPS-CMs) and to quantify the damage and functional impairment of the ischemic cardiomyocytes. Exposure to 2% oxygen without glucose and serum increases the percentage of injured cells, which is indicated by staining of the nucleus with propidium iodide, and decreases cellular viability. These conditions also decrease the contractility of hiPS-CMs as confirmed by displacement vector field analysis of microscopic video images. This protocol may furthermore provide a convenient method for personalized drug screening by facilitating the use of hiPS cells from individual patients. Therefore, this model of ischemic heart disease, based on iPS-CMs of human origin, can provide a useful platform for drug screening and further research on ischemic heart disease.

We present a model of ischemic heart disease using cardiomyocytes derived from human induced pluripotent stem cells, together with a method for quantitative evaluation of tissue damage caused by ischemia. This model can provide a useful platform for drug screening and further research on ischemic heart disease.

Ischemic heart disease is a significant cause of death worldwide. It has therefore been the subject of a tremendous amount of research, often with ...

Directed Induction of Retinal Organoids from Human Pluripotent Stem Cells

Retinal cell transplantation is a promising therapeutic approach, which could restore the retinal architecture and stabilize or even improve the visual capabilities to the degenerated retina. Nevertheless, progress in cell replacement therapy presently faces the challenges of requiring an off-the-shelf source of high quality and standardized human retinas. Therefore, an easy and stable protocol is needed for the experiments. Here, we develop an optimized protocol, based on a self-organizing method with the use of exogenous molecules and reagent A as well as manual excision to generate the three-dimensional human retina organoids (RO). The human Pluripotent Stem Cells (PSCs)-derived RO expresses specific markers for photoreceptors. With the addition of COCO, a multifunctional antagonist, the differentiation efficiency of photoreceptor precursors and cones is significantly increased. The efficient use of this system, which has the benefits of cell lines and primary cells, and without the sourcing issues associated with the latter, could produce confluent retinal cells, especially photoreceptors. Thus, the differentiation of PSCs to RO provides an optimal and biorelevant platform for disease modelling, drug screening and cell transplantation.

Using a self-organizing method, we develop a protocol with the addition of COCO that could significantly increase the generation of photoreceptors.

Retinal cell transplantation is a promising therapeutic approach, which could restore the retinal architecture and stabilize or even improve the visual ...

Retinal Organoid Induction System for Derivation of 3D Retinal Tissues from Human Pluripotent Stem Cells

Retinal degenerative diseases are the main causes of irreversible blindness without effective treatment. Pluripotent stem cells that have the potential to differentiate into all types of retinal cells, even mini-retinal tissues, hold huge promises for patients with these diseases and many opportunities in disease modeling and drug screening. However, the induction process from hPSCs to retinal cells is complicated and time-consuming. Here, we describe an optimized retinal induction protocol to generate retinal tissues with high reproducibility and efficiency, suitable for various human pluripotent stem cells. This protocol is performed without the addition of retinoic acid, which benefits the enrichment of cone photoreceptors. The advantage of this protocol is the quantification of EB size and plating density to significantly enhance the efficiency and repeatability of retinal induction. With this method, all major retinal cells sequentially appear and recapitulate the main steps of retinal development. It will facilitate downstream applications, such as disease modeling and cell therapy.

Here we describe an optimized retinal organoid induction system, which is suitable for various human pluripotent stem cell lines to generate retinal tissues with high reproducibility and efficiency.

Retinal degenerative diseases are the main causes of irreversible blindness without effective treatment. Pluripotent stem cells that have the potential to ...

Ultrasound-Guided Induced Pluripotent Stem Cell-Derived Cardiomyocyte Implantation in Myocardial Infarcted Mice

The key objective of cell therapy after myocardial infarction (MI) is to effectively enhance the cell grafted rate, and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are a promising cell source for cardiac repair after ischemic damage. However, a low grafted rate is a significant obstacle for effective cardiac tissue regeneration after transplantation. This protocol shows that multiple hiPSC-CM ultrasound-guided percutaneous injections into an MI area effectively increase cell transplantation rates. The study also describes the entire hiPSC-CM culture process, pretreatment, and ultrasound-guided percutaneous delivery methods. In addition, the use of human mitochondrial DNA help detect the absence of hiPSC-CMs in other mouse organs. Lastly, this paper describes the changes in cardiac function, angiogenesis, cell size, and apoptosis at the infarcted border zone in mice 4 weeks after cell delivery. It can be concluded that echocardiography-guided percutaneous injection of the left ventricular myocardium is a feasible, relatively invasive, satisfactory, repeatable, and effective cellular therapy.

Ultrasound-guided cell delivery around the site of myocardial infarction in mice is a safe, effective, and convenient way of cell transplantation.

The key objective of cell therapy after myocardial infarction (MI) is to effectively enhance the cell grafted rate, and human induced pluripotent stem ...

Technical Applications of Microelectrode Array and Patch Clamp Recordings on Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Drug-induced cardiotoxicity is the leading cause of drug attrition and withdrawal from the market. Therefore, using appropriate preclinical cardiac safety assessment models is a critical step during drug development. Currently, cardiac safety assessment is still highly dependent on animal studies. However, animal models are plagued by poor translational specificity to humans due to species-specific differences, particularly in terms of cardiac electrophysiological characteristics. Thus, there is an urgent need to develop a reliable, efficient, and human-based model for preclinical cardiac safety assessment. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have emerged as an invaluable in vitro model for drug-induced cardiotoxicity screening and disease modeling. hiPSC-CMs can be obtained from individuals with diverse genetic backgrounds and various diseased conditions, making them an ideal surrogate to assess drug-induced cardiotoxicity individually. Therefore, methodologies to comprehensively investigate the functional characteristics of hiPSC-CMs need to be established. In this protocol, we detail various functional assays that can be assessed on hiPSC-CMs, including the measurement of contractility, field potential, action potential, and calcium handling. Overall, the incorporation of hiPSC-CMs into preclinical cardiac safety assessment has the potential to revolutionize drug development.

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have emerged as a promising in vitro model for drug-induced cardiotoxicity screening and disease modeling. Here, we detail a protocol for measuring the contractility and electrophysiology of hiPSC-CMs.

Drug-induced cardiotoxicity is the leading cause of drug attrition and withdrawal from the market. Therefore, using appropriate preclinical cardiac safety ...