The authors thank the Cornell University, Biotechnology Resource Center Imaging Facility for their help with fluorescence activated cell sorting. We also thank Molly Gheller for her help with participant recruitment and Erica Bender for conducting the skeletal muscle biopsies. Finally, we thank the participants for their time and participation in the study.This work was supported by the National Institute on Aging of the National Institutes of Health under Award Number R01AG058630 (to B.D.C. and A.E.T.), by a Glenn Foundation for Medical Research and American Federation for Aging Research Grant for Junior Faculty (to B.D.C.), and by the President&#39;s Council for Cornell Women (to A.E.T.).

<ol>
	<li>Janssen, I., Heymsfield, S. B., Wang, Z., Ross, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Skeletal+muscle+mass+and+distribution+in+468+men+and+women+aged+18-88+yr.">Skeletal muscle mass and distribution in 468 men and women aged 18-88 yr.</a> Journal of Applied Physiology. 89 (1), 81-88 (2000).</li><li>D'Souza, D. 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=Decreased+satellite+cell+number+and+function+in+humans+and+mice+with+type+1+diabetes+is+the+result+of+altered+notch+signaling.">Decreased satellite cell number and function in humans and mice with type 1 diabetes is the result of altered notch signaling.</a> Diabetes. 65 (10), 3053-3061 (2016).</li><li>Scheele, C., 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=Satellite+cells+derived+from+Obese+humans+with+type+2+diabetes+and+differentiated+into+Myocytes+in+vitro+exhibit+abnormal+response+to+IL-6.">Satellite cells derived from Obese humans with type 2 diabetes and differentiated into Myocytes in vitro exhibit abnormal response to IL-6.</a> PLoS One. 7 (6), e39657 (2012).</li><li>Riddle, E. S., Bender, E. L., Thalacker-Mercer, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expansion+capacity+of+human+muscle+progenitor+cells+differs+by+age,+sex,+and+metabolic+fuel+preference.">Expansion capacity of human muscle progenitor cells differs by age, sex, and metabolic fuel preference.</a> American Journal of Physiology: Cell Physiology. 315 (5), C643-C652 (2018).</li><li>Charville, G. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ex+vivo+expansion+and+in+vivo+self-renewal+of+human+muscle+stem+cells.">Ex vivo expansion and in vivo self-renewal of human muscle stem cells.</a> Stem Cell Reports. 5 (4), 621-632 (2015).</li><li>Alexander, M. 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=CD82+Is+a+Marker+for+Prospective+Isolation+of+Human+Muscle+Satellite+Cells+and+Is+Linked+to+Muscular+Dystrophies.">CD82 Is a Marker for Prospective Isolation of Human Muscle Satellite Cells and Is Linked to Muscular Dystrophies.</a> Cell Stem Cell. 19 (6), 800-807 (2016).</li><li>Thalacker-Mercer, 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=Cluster+analysis+reveals+differential+transcript+profiles+associated+with+resistance+training-induced+human+skeletal+muscle+hypertrophy.">Cluster analysis reveals differential transcript profiles associated with resistance training-induced human skeletal muscle hypertrophy.</a> Physiological Genomics. 45 (12), 499-507 (2013).</li><li>Garcia, S. 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=High-Yield+Purification,+Preservation,+and+Serial+Transplantation+of+Human+Satellite+Cells.">High-Yield Purification, Preservation, and Serial Transplantation of Human Satellite Cells.</a> Stem Cell Reports. 10 (3), 1160-1174 (2018).</li><li>Yokoyama, W. M., Thompson, M. L., Ehrhardt, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cryopreservation+and+thawing+of+cells.">Cryopreservation and thawing of cells.</a> Current Protocols in Immunology. , (2012).</li><li>Bareja, A., Billin, A. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Satellite+cell+therapy+-+from+mice+to+men.">Satellite cell therapy - from mice to men.</a> Skeletal Muscle. 3 (1), 2 (2013).</li><li>Riddle, E. S., Bender, E. L., Thalacker-Mercer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcript+profile+distinguishes+variability+in+human+myogenic+progenitor+cell+expansion+capacity.">Transcript profile distinguishes variability in human myogenic progenitor cell expansion capacity.</a> Physiological Genomics. 50 (10), 817-827 (2018).</li><li>Xu, X., 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+Satellite+Cell+Transplantation+and+Regeneration+from+Diverse+Skeletal+Muscles.">Human Satellite Cell Transplantation and Regeneration from Diverse Skeletal Muscles.</a> Stem Cell Reports. 5 (3), 419-434 (2015).</li></ol>

The authors have nothing to disclose.

Primary hMPCs are an important research model used to understand skeletal muscle biology and the regenerative process. Additionally, hMPCs have the potential to be used for therapy. However, there are recognized challenges in using primary hMPCs for both research and therapy, including the limited understanding of cells derived from humans10. There is also a large degree of variation in the expansion capacity among donor cultures, which limits the potential for use of hMPCs and can affect research...

Skeletal muscle is the largest organ system in the human body, accounting for 30&#8722;40% of whole body mass1. In addition to its well-recognized role in locomotion, skeletal muscle maintains body temperature and posture, and plays a central role in whole body nutrient homeostasis. Research involving human participants, animals, and cell culture models are all valuable to address questions pertaining to skeletal muscle biology and regeneration. Isolation and culture of human primary muscle progenitor cells (hMPCs) provides a robust model that allows for cell culture techniques and manipulations to be applied to human samples. An advantage of using hMPCs is that they retain the genetic and metabolic phenotype from each donor2,3. Maintenance of the donor phenotype allows researchers to examine inter-individual variation in the myogenic process. For example, we have employed our hMPC characterization method to identify age- and sex-related differences in hMPC population expansion capacity4.
The purpose of this protocol is to detail techniques to isolate, culture, characterize, and differentiate&#160;hMPCs from skeletal muscle biopsy tissue. Building on previous work that described hMPCs and identified potential cell surface makers for hMPC isolation5,6, this protocol fills a critical gap in knowledge by linking the isolation to the characterization of hMPCs. Further, the detailed step-by-step instructions included in this protocol make hMPC isolation and characterization accessible to a broad scientific audience, including those with limited prior experience with hMPCs. Our protocol is among the first to describe use of an imaging cytometer to track cell populations. Newly designed imaging cytometers are state-of-the-art, high-throughput, and microplate-based, enabling live cell imaging, cell counting, and multichannel fluorescence analysis of all cells in each well of a culture vessel within minutes. This system allows for rapid quantification of dynamic changes in proliferation and viability of an entire cell population with only minimal disruption to the culture. For example, we are able to perform objective measures of confluence on successive days in vitro to determine growth kinetics of each culture derived from different donors. Many protocols in the literature, particularly those involving the differentiation of MPCs, require cells to reach a defined level of confluence before initiating differentiation or treatment7. Our method allows for objective determination of the confluence of each well in a culture vessel allowing researchers to initiate treatment in an unbiased, non-subjective manner.
In the past, a major limitation of using primary hMPCs was low yields that limit the number of cells available for experiments. We and others have shown the yield of MPCs from skeletal muscle biopsy tissue is 1&#8722;15 MPCs per milligram of tissue (Figure 1)8. Because our protocol allows for four passages of the cells prior to purification with fluorescence activated cell sorting (FACS), our cryopreserved hMPC yields, derived from small amounts of biopsy tissue (50&#8722;100 mg), are sufficient to address research aims where multiple experiments are required. Our FACS protocol produces a ~80% pure (Pax7 positive) MPC population, thus our protocol is optimized for both yield and purity.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.25% Trypsin, 2.21 mM EDTA</td>
			<td>Corning</td>
			<td>25-053-Cl</td>
			<td>Trypsin used for removing adherent hMPCs from cell culture vessels</td>
		</tr>
		<tr>
			<td>10 cm cell culture plate</td>
			<td>VWR</td>
			<td>664160</td>
			<td>Plates used for culturing hMPCs</td>
		</tr>
		<tr>
			<td>15 mL Falcon tube</td>
			<td>Falcon</td>
			<td>352196</td>
			<td>15 mL conical tubes used throughout the hMPC isolation and culturing protocols</td>
		</tr>
		<tr>
			<td>24 well cell culture plate</td>
			<td>Grenier Bio-One</td>
			<td>662 160</td>
			<td>Plates used for culturing hMPCs</td>
		</tr>
		<tr>
			<td>7-AAD Viability Staining Solution</td>
			<td>eBioscience</td>
			<td>00-6993-50</td>
			<td>Viability stain for identifying living cells during FACS sorting</td>
		</tr>
		<tr>
			<td>Alexa Fluor 488 anti-human CD29, Clone: TS2/16</td>
			<td>BioLegend</td>
			<td>303016</td>
			<td>Conjugated antibody for FACS&#160;</td>
		</tr>
		<tr>
			<td>Black 96-well cell culture plate</td>
			<td>Grenier Bio-One</td>
			<td>655079</td>
			<td>96-well cell culture plate ideal for fluorescent imaging using the Celigo S</td>
		</tr>
		<tr>
			<td>Celigo S</td>
			<td>Nexcelcom Bioscience</td>
			<td></td>
			<td>Imaging cytometer used to track hMPC cultures</td>
		</tr>
		<tr>
			<td>Cell Strainer</td>
			<td>VWR</td>
			<td>352350</td>
			<td>Cell strainer to eliminate large pieces of debris during muscle biopsy processing</td>
		</tr>
		<tr>
			<td>Collagen Type I (Rat Tail)</td>
			<td>Corning</td>
			<td>354236</td>
			<td>Collagen for coating cell culture plates&#160;</td>
		</tr>
		<tr>
			<td>Collagenase D</td>
			<td>Roche</td>
			<td>11 088 882 001</td>
			<td>Used for degradation of collagen and other connective tissue in the skeletal muscle biopsy tissue</td>
		</tr>
		<tr>
			<td>Dimethyl Sulfoxide</td>
			<td>VWR</td>
			<td>WN182</td>
			<td>Used for cryopreservation of hMPCs</td>
		</tr>
		<tr>
			<td>Dispase II</td>
			<td>Sigma Life Sciences</td>
			<td>D4693</td>
			<td>A protease used for enzymatic digestion of skeletal muscle biopsy tissue</td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s Modified Eagle Medium Low Glucose powder</td>
			<td>Gibco</td>
			<td>31600-034</td>
			<td>Low glucose DMEM for muscle biopsy processing</td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s Phosphate Buffered Saline</td>
			<td>Gibco</td>
			<td>21600-010</td>
			<td>PBS for muscle biopsy processing</td>
		</tr>
		<tr>
			<td>EDTA Disodium Salt Dihydrate</td>
			<td>J.T. Baker</td>
			<td>4040-01&#160;</td>
			<td>Required for FACS buffer</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>VWR</td>
			<td>89510-186&#160;</td>
			<td>Fetal bovine serum used for hMPC growth media</td>
		</tr>
		<tr>
			<td>Ham&#39;s F12</td>
			<td>Gibco</td>
			<td>21700-026</td>
			<td>Base media for hMPCs</td>
		</tr>
		<tr>
			<td>Heat Inactivated Equine Serum</td>
			<td>Gibco</td>
			<td>26-050-070</td>
			<td>Horse serum used to make hMPC differentiation media</td>
		</tr>
		<tr>
			<td>Hemocytometer</td>
			<td>iNCyto</td>
			<td>DHC-N0105</td>
			<td>Used to count cells</td>
		</tr>
		<tr>
			<td>Hibernate A</td>
			<td>Gibco</td>
			<td>A1247501</td>
			<td>Media for preserving skeletal muscle biopsy tissue</td>
		</tr>
		<tr>
			<td>Hoechst 33342, trihydrochloride, trihydrate</td>
			<td>Life Technologies</td>
			<td>H21492</td>
			<td>DNA stain for identifying all cells using the Celigo S</td>
		</tr>
		<tr>
			<td>Isopropanol</td>
			<td>Fisher Scientific</td>
			<td>A416P-4</td>
			<td>Used for controlled rate freezing of hMPCs</td>
		</tr>
		<tr>
			<td>Moxi buffer</td>
			<td>Orflo</td>
			<td>MXA006</td>
			<td>Buffer for automated cell counter</td>
		</tr>
		<tr>
			<td>Moxi Cassettes</td>
			<td>Orflo</td>
			<td>MXC002</td>
			<td>Cassesttes for automated cell counter</td>
		</tr>
		<tr>
			<td>Moxi z Mini Automated Cell Counter</td>
			<td>Orflo</td>
			<td></td>
			<td>Automated cell counter</td>
		</tr>
		<tr>
			<td>Mr. Frosty Freezing Container</td>
			<td>Thermo Fisher Scientific</td>
			<td>5100-0001</td>
			<td>Commerically available controlled rate cell freezing container</td>
		</tr>
		<tr>
			<td>Normal Goat Serum (10%)</td>
			<td>Thermo Fisher Scientific</td>
			<td>50062Z</td>
			<td>Goat serum used in FACS buffer</td>
		</tr>
		<tr>
			<td>PE-Cy7 Mouse Anti-human CD56 , Clone: B159</td>
			<td>BD Pharmingen</td>
			<td>557747</td>
			<td>Conjugated antibody for FACS&#160;</td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin 100X Solution</td>
			<td>Corning</td>
			<td>30-002-CI</td>
			<td>Antibiotics added to culture media</td>
		</tr>
		<tr>
			<td>Propidium iodide</td>
			<td>Thermo Fisher Scientific</td>
			<td>P3566</td>
			<td>DNA stain for identifying dead cells using the Celigo S</td>
		</tr>
		<tr>
			<td>Recombinant Human basic fibroblast growth factor</td>
			<td>Promega</td>
			<td>G5071</td>
			<td>Supplement in hMPC growth media to prevent spontaneous differentiation</td>
		</tr>
		<tr>
			<td>Recovery Cell Culture Freezing Medium&#160;</td>
			<td>Gibco</td>
			<td>12648-010</td>
			<td>Media used to cryoperseve muscle biopsy slurries</td>
		</tr>
		<tr>
			<td>Sodium Bicarbonate</td>
			<td>Fisher Scientific</td>
			<td>S233-3</td>
			<td>Added to Ham&#39;s F12</td>
		</tr>
		<tr>
			<td>Sterile Round Bottom 5 mL tubes</td>
			<td>VWR</td>
			<td>60818-565</td>
			<td>Tubes used for FACS</td>
		</tr>
		<tr>
			<td>UltraComp eBeads</td>
			<td>eBioscience</td>
			<td>01-2222-42</td>
			<td>Compensation beads fort calibrating flow FACS settings</td>
		</tr>
	</tbody>
</table>

isolation, culture, characterization, and differentiation of human muscle progenitor cells from the skeletal muscle biopsy procedure

The use of primary human tissue and cells is ideal for the investigation of biological and physiological processes such as the skeletal muscle regenerative process. There are recognized challenges to working with human primary adult stem cells, particularly human muscle progenitor cells (hMPCs) derived from skeletal muscle biopsies, including low cell yield from collected tissue and a large degree of donor heterogeneity of growth and death parameters among cultures. While incorporating heterogeneity into experimental design requires a larger sample size to detect significant effects, it also allows us to identify mechanisms that underlie variability in hMPC&#160;expansion capacity, and thus allows us to better understand heterogeneity in skeletal muscle regeneration. Novel mechanisms that distinguish the expansion capacity of cultures have the potential to lead to the development of therapies to improve skeletal muscle regeneration.

Representative flow cytometry results of hMPC isolation from human muscle tissue can be viewed in Figure 1. hMPCs can be identified by first gating events based on side scatter and forward scatter to eliminate dead cells or debris, followed by selecting only cells which are negative for 7-AAD and therefore are viable. Selection of cells positive for both the cell surface markers CD56 and CD29 represents the hMPC population. A biopsy of 60 mg only provides app...

Watch this Scientific Journal Video about Isolation, Culture, Characterization, and Differentiation of Human Muscle Progenitor Cells from the Skeletal Muscle Biopsy Procedure at JoVE.com

Isolation, Culture, Characterization, and Differentiation of Human Muscle Progenitor Cells from the Skeletal Muscle Biopsy Procedure

We present techniques for isolating, culturing, characterizing, and differentiating human primary muscle progenitor cells (hMPCs) obtained from skeletal muscle biopsy tissue. hMPCs obtained and characterized through these methods can be used to subsequently address research questions related to human myogenesis and skeletal muscle regeneration.

The use of primary human tissue and cells is ideal for the investigation of biological and physiological processes such as the skeletal muscle ...

isolation-culture-characterization-differentiation-human-muscle

Research

JoVE Journal

Developmental Biology

8.2K Views.  Cornell University. We present techniques for isolating, culturing, characterizing, and differentiating human primary muscle progenitor cells (hMPCs) obtained from skeletal muscle biopsy tissue. hMPCs obtained and characterized through these methods can be used to subsequently address research questions related to human myogenesis and skeletal muscle regeneration.

Video: Isolation, Culture, Characterization, and Differentiation of Human Muscle Progenitor Cells from the Skeletal Muscle Biopsy Procedure

Isolation and Quantitative Immunocytochemical Characterization of Primary Myogenic Cells and Fibroblasts from Human Skeletal Muscle

The repair and regeneration of skeletal muscle requires the action of satellite cells, which are the resident muscle stem cells. These can be isolated from human muscle biopsy samples using enzymatic digestion and their myogenic properties studied in culture. Quantitatively, the two main adherent cell types obtained from enzymatic digestion are: (i) the satellite cells (termed myogenic cells or muscle precursor cells), identified initially as CD56+ and later as CD56+/desmin+ cells and (ii) muscle-derived fibroblasts, identified as CD56&#8211; and TE-7+. Fibroblasts proliferate very efficiently in culture and in mixed cell populations these cells may overrun myogenic cells to dominate the culture. The isolation and purification of different cell types from human muscle is thus an important methodological consideration when trying to investigate the innate behavior of either cell type in culture. Here we describe a system of sorting based on the gentle enzymatic digestion of cells using collagenase and dispase followed by magnetic activated cell sorting (MACS) which gives both a high purity (&#62;95% myogenic cells) and good yield (~2.8 x 106 &#177; 8.87 x 105 cells/g tissue after 7 days in vitro) for experiments in culture. This approach is based on incubating the mixed muscle-derived cell population with magnetic microbeads beads conjugated to an antibody against CD56 and then passing cells though a magnetic field. CD56+ cells bound to microbeads are retained by the field whereas CD56&#8211; cells pass unimpeded through the column. Cell suspensions from any stage of the sorting process can be plated and cultured. Following a given intervention, cell morphology, and the expression and localization of proteins including nuclear transcription factors can be quantified using immunofluorescent labeling with specific antibodies and an image processing and analysis package.

The main adherent cell types derived from human muscle are myogenic cells and fibroblasts. Here, cell populations are enriched using magnetic-activated cell sorting based on the CD56 antigen. Subsequent immunolabelling with specific antibodies and use of image analysis techniques allows quantification of cytoplasmic and nuclear characteristics in individual cells.

The repair and regeneration of skeletal muscle requires the action of satellite cells, which are the resident muscle stem cells. These can be isolated ...

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 ...

Using Isolated Mitochondria from Minimal Quantities of Mouse Skeletal Muscle for High throughput Microplate Respiratory Measurements

Skeletal muscle mitochondria play a specific role in many disease pathologies. As such, the measurement of oxygen consumption as an indicator of mitochondrial function in this tissue has become more prevalent. Although many technologies and assays exist that measure mitochondrial respiratory pathways in a variety of cells, tissue and species, there is currently a void in the literature in regards to the compilation of these assays using isolated mitochondria from mouse skeletal muscle for use in microplate based technologies. Importantly, the use of microplate based respirometric assays is growing among mitochondrial biologists as it allows for high throughput measurements using minimal quantities of isolated mitochondria. Therefore, a collection of microplate based respirometric assays were developed that are able to assess mechanistic changes/adaptations in oxygen consumption in a commonly used animal model. The methods presented herein provide step-by-step instructions to perform these assays with an optimal amount of mitochondrial protein and reagents, and high precision as evidenced by the minimal variance across the dynamic range of each assay.

The methods presented provide step-by-step instructions for the performance of a collection of microplate based respirometric assays using isolated mitochondria from minimal quantities of mouse skeletal muscle. These assays are able to measure mechanistic changes/adaptations in mitochondrial oxygen consumption in a commonly used animal model.

Skeletal muscle mitochondria play a specific role in many disease pathologies. As such, the measurement of oxygen consumption as an indicator of ...

Large-Scale Production of Cardiomyocytes from Human Pluripotent Stem Cells Using a Highly Reproducible Small Molecule-Based Differentiation Protocol

Maximizing the benefit of human pluripotent stem cells (hPSCs) for research, disease modeling, pharmaceutical and clinical applications requires robust methods for the large-scale production of functional cell types, including cardiomyocytes. Here we demonstrate that the temporal manipulation of WNT, TGF-&#946;, and SHH signaling pathways leads to highly efficient cardiomyocyte differentiation of single-cell passaged hPSC lines in both static suspension and stirred suspension bioreactor systems. Employing this strategy resulted in ~ 100% beating spheroids, consistently containing &#62; 80% cardiac troponin T-positive cells after 15 days of culture, validated in multiple hPSC lines. We also report on a variation of this protocol for use with cell lines not currently adapted to single-cell passaging, the success of which has been verified in 42 hPSC lines. Cardiomyocytes generated using these protocols express lineage-specific markers and show expected electrophysiological functionalities. Our protocol presents a simple, efficient and robust platform for the large-scale production of human cardiomyocytes.

Here, we present a robust, fast and scalable cardiomyocyte differentiation protocol for human pluripotent stem cells (hPSCs). Cardiomyocytes derived using this large-scale method can provide sufficient cell numbers for their effective use in human cardiovascular disease modeling, high-throughput drug screening, and potentially clinical applications.

Maximizing the benefit of human pluripotent stem cells (hPSCs) for research, disease modeling, pharmaceutical and clinical applications requires robust ...

Preparation and Culture of Myogenic Precursor Cells/Primary Myoblasts from Skeletal Muscle of Adult and Aged Humans

Skeletal muscle homeostasis depends on muscle growth (hypertrophy), atrophy and regeneration. During ageing and in several diseases, muscle wasting occurs. Loss of muscle mass and function is associated with muscle fiber type atrophy, fiber type switching, defective muscle regeneration associated with dysfunction of satellite cells, muscle stem cells, and other pathophysiological processes. These changes are associated with changes in intracellular as well as local and systemic niches. In addition to most commonly used rodent models of muscle ageing, there is a need to study muscle homeostasis and wasting using human models, which due to ethical implications, consist predominantly of in vitro cultures. Despite the wide use of human Myogenic Progenitor Cells (MPCs) and primary myoblasts in myogenesis, there is limited data on using human primary myoblast and myotube cultures to study molecular mechanisms regulating different aspects of age-associated muscle wasting, aiding in the validation of mechanisms of ageing proposed in rodent muscle. The use of human MPCs, primary myoblasts and myotubes isolated from adult and aged people, provides a physiologically relevant model of molecular mechanisms of processes associated with muscle growth, atrophy and regeneration. Here we describe in detail a robust, inexpensive, reproducible and efficient protocol for the isolation and maintenance of human MPCs&#160;and their progeny&#160;&#8212; myoblasts and myotubes from human muscle samples using enzymatic digestion. Furthermore, we have determined the passage number at which primary myoblasts from adult and aged people undergo senescence in an in vitro culture. Finally, we show the ability to transfect these myoblasts and the ability to characterize their proliferative and differentiation capacity and propose their suitability for performing functional studies of molecular mechanisms of myogenesis and muscle wasting in vitro.

This protocol describes a robust, reproducible and simple method of isolation and culture of myoblast progenitor cells from the skeletal muscle of adult and aged people. The muscles used here include foot and leg muscles. This approach enables the isolation of an enriched population of primary myoblasts for functional studies.

Skeletal muscle homeostasis depends on muscle growth (hypertrophy), atrophy and regeneration. During ageing and in several diseases, muscle wasting ...

Isolation of Endothelial Progenitor Cells from Human Umbilical Cord Blood

The existence of endothelial progenitor cells (EPCs) in peripheral blood and its involvement in vasculogenesis was first reported by Ashara and colleagues1. Later, others documented the existence of similar types of EPCs originating from bone marrow2,3. More recently, Yoder and Ingram showed that EPCs derived from umbilical cord blood had a higher proliferative potential compared to ones isolated from adult peripheral blood4,5,6. Apart from being involved in postnatal vasculogenesis, EPCs have also shown promise as a cell source for creating tissue-engineered vascular and heart valve constructs7,8. Various isolation protocols exist, some of which involve the cell sorting of mononuclear cells (MNCs) derived from the sources mentioned earlier with the help of endothelial and hematopoietic markers, or culturing these MNCs with specialized endothelial growth medium, or a combination of these techniques9. Here, we present a protocol for the isolation and culture of EPCs using specialized endothelial medium supplemented with growth factors, without the use of immunosorting, followed by the characterization of the isolated cells using Western blotting and immunostaining.

The goal of this protocol is to isolate endothelial progenitor cells from umbilical cord blood. Some of the applications include using these cells as a biomarker for identifying patients with cardiovascular risk, treating ischemic diseases, and creating tissue-engineered vascular and heart valve constructs.

The existence of endothelial progenitor cells (EPCs) in peripheral blood and its involvement in vasculogenesis was first reported by Ashara and ...

Application of Chronic Stimulation to Study Contractile Activity-induced Rat Skeletal Muscle Phenotypic Adaptations

Skeletal muscle is a highly adaptable tissue, as its biochemical and physiological properties are greatly altered in response to chronic exercise. To investigate the underlying mechanisms that bring about various muscle adaptations, a number of exercise protocols such as treadmill, wheel running, and swimming exercise have been used in the animal studies. However, these exercise models require a long period of time to achieve muscle adaptations, which may be also regulated by humoral or neurological factors, thus limiting their applications in studying the muscle-specific contraction-induced adaptations. Indirect low frequency stimulation (10 Hz) to induce chronic contractile activity (CCA) has been used as an alternative model for exercise training, as it can successfully lead to muscle mitochondrial adaptations within 7 days, independent of systemic factors. This paper details the surgical techniques required to apply the treatment of CCA to the skeletal muscle of rats, for widespread application in future studies.

This protocol describes the use of the chronic contractile activity model of exercise to observe stimulation-induced skeletal muscle adaptations in the rat hindlimb.

Skeletal muscle is a highly adaptable tissue, as its biochemical and physiological properties are greatly altered in response to chronic exercise. To ...

Identification of Skeletal Muscle Satellite Cells by Immunofluorescence with Pax7 and Laminin Antibodies

Immunofluorescence is an effective method that helps to identify different cell types on tissue sections. In order to study the desired cell population, antibodies for specific cell markers are applied on tissue sections. In adult skeletal muscle, satellite cells (SCs) are stem cells that contribute to muscle repair and regeneration. Therefore, it is important to visualize and trace the satellite cell population under different physiological conditions. In resting skeletal muscle, SCs reside between the basal lamina and myofiber plasma membrane. A commonly used marker for identifying SCs on the myofibers or in cell culture is the paired box protein Pax7. In this article, an optimized Pax7 immunofluorescence protocol on skeletal muscle sections is presented that minimizes non-specific staining and background. Another antibody that recognizes a protein (laminin) of the basal lamina was also added to help identify SCs. Similar protocols can also be used to perform double or triple labeling with Pax7 and antibodies for additional proteins of interest.

The precise identification of satellite cells is essential for studying their functions under various physiological and pathological conditions. This article presents a protocol to identify satellite cells on adult skeletal muscle sections by immunofluorescence-based staining.

Immunofluorescence is an effective method that helps to identify different cell types on tissue sections. In order to study the desired cell population, ...

Performing Human Skeletal Muscle Xenografts in Immunodeficient Mice

Treatment effects observed in animal studies often fail to be recapitulated in clinical trials. While this problem is multifaceted, one reason for this failure is the use of inadequate laboratory models. It is challenging to model complex human diseases in traditional laboratory organisms, but this issue can be circumvented through the study of human xenografts. The surgical method we describe here allows for the creation of human skeletal muscle xenografts, which can be used to model muscle disease and to carry out preclinical therapeutic testing. Under an Institutional Review Board (IRB)-approved protocol, skeletal muscle specimens are acquired from patients and then transplanted into NOD-Rag1null IL2r&gamma;null (NRG) host mice. These mice are ideal hosts for transplantation studies due to their inability to make mature lymphocytes and are thus unable to develop cell-mediated and humoral adaptive immune responses. Host mice are anaesthetized with isoflurane, and the mouse tibialis anterior and extensor digitorum longus muscles are removed. A piece of human muscle is then placed in the empty tibial compartment and sutured to the proximal and distal tendons of the peroneus longus muscle. The xenografted muscle is spontaneously vascularized and innervated by the mouse host, resulting in robustly regenerated human muscle that can serve as a model for preclinical studies.

Complex human diseases can be challenging to model in traditional laboratory model systems. Here, we describe a surgical approach to model human muscle disease through the transplantation of human skeletal muscle biopsies into immunodeficient mice.

Treatment effects observed in animal studies often fail to be recapitulated in clinical trials. While this problem is multifaceted, one reason for this ...

Isolation and Differentiation of Primary Myoblasts from Mouse Skeletal Muscle Explants

Primary myoblasts are undifferentiated proliferating precursors of skeletal muscle. They can be cultured and studied as muscle precursors or induced to differentiate into later stages of muscle development. The protocol provided here describes a robust method for the isolation and culture of a highly proliferative population of myoblast cells from young adult mouse skeletal muscle explants. These cells are useful for the study of the metabolic properties of skeletal muscle of different mouse models, as well as in other downstream applications such as transfection with exogenous DNA or transduction with viral expression vectors. The level of differentiation and metabolic profile of these cells depends on the length of exposure, and composition of the media used to induce myoblast differentiation. These methods provide a robust system for the study of mouse muscle cell metabolism ex vivo. Importantly, unlike in vivo models, the methods described here provide a cell population that can be expanded and studied with high levels of reproducibility.

Myoblasts are proliferating precursor cells that differentiate to form polynucleated myotubes and eventually skeletal muscle myofibers. Here, we present a protocol for efficient isolation and culture of primary myoblasts from young adult mouse skeletal muscles. The method enables molecular, genetic, and metabolic studies of muscle cells in culture.

Primary myoblasts are undifferentiated proliferating precursors of skeletal muscle. They can be cultured and studied as muscle precursors or induced to ...