The authors thank Giulio Cossu, Martina Ragazzi and the whole laboratory for helpful discussion and support, and Jeff Chamberlain for kindly providing MyoD-ER vector. All the experiments involving live animals were completed in accordance and compliance with all relevant regulatory and institutional agencies, regulations and guidelines. Work in the authors laboratory is supported by UK Medical Research Council, European Community 7th Framework projects Optistem and Biodesign and the Italian Duchenne Parent Project.

1. Assessment of Myogenic and Engraftment Potential
<ol>
	<li>In vitro: MyoD-induced differentiation
	<ol>
		<li>Generate a stable cell line of IDEMs transduced with the tamoxifen-inducible MyoD-ER lentiviral vector, titrating the multiplicity of infection (MOI; e.g.&#160;1, 5 and 50) using the staining described in 1.1.9 (MyHC) as an outcome of the efficiency of the procedure.</li>
		<li>Coat a 3.5 cm dish with 1 ml of 1% Matrigel and incubate for 30 min at 37 &#176;C.</li>
		<li>Wash the plate twice...

<ol>
	<li>Dellavalle, 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=Pericytes+of+human+skeletal+muscle+are+myogenic+precursors+distinct+from+satellite+cells.">Pericytes of human skeletal muscle are myogenic precursors distinct from satellite cells.</a> Nat. Cell Biol. 9, 255-267 (2007).</li><li>Minasi, M. G., 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+meso-angioblast:+a+multipotent,+self-renewing+cell+that+originates+from+the+dorsal+aorta+and+differentiates+into+most+mesodermal+tissues.">The meso-angioblast: a multipotent, self-renewing cell that originates from the dorsal aorta and differentiates into most mesodermal tissues.</a> Development. 129, 2773-2783 (2002).</li><li>Dellavalle, 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=Pericytes+resident+in+postnatal+skeletal+muscle+differentiate+into+muscle+fibres+and+generate+satellite+cells.">Pericytes resident in postnatal skeletal muscle differentiate into muscle fibres and generate satellite cells.</a> Nat. Commun. 2, 499 (2011).</li><li>Tedesco, F. S., Dellavalle, A., Diaz-Manera, J., Messina, G., Cossu, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Repairing+skeletal+muscle:+regenerative+potential+of+skeletal+muscle+stem+cells.">Repairing skeletal muscle: regenerative potential of skeletal muscle stem cells.</a> J. Clin. Invest. 120, 11-19 (2010).</li><li>Sampaolesi, 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=Cell+therapy+of+alpha-sarcoglycan+null+dystrophic+mice+through+intra-arterial+delivery+of+mesoangioblasts.">Cell therapy of alpha-sarcoglycan null dystrophic mice through intra-arterial delivery of mesoangioblasts.</a> Science. 301, 487-492 (2003).</li><li>Sampaolesi, 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=Mesoangioblast+stem+cells+ameliorate+muscle+function+in+dystrophic+dogs.">Mesoangioblast stem cells ameliorate muscle function in dystrophic dogs.</a> Nature. 444, 574-579 (2006).</li><li>Tedesco, F. 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=Transplantation+of+Genetically+Corrected+Human+iPSC-Derived+Progenitors+in+Mice+with+Limb-Girdle+Muscular+Dystrophy.">Transplantation of Genetically Corrected Human iPSC-Derived Progenitors in Mice with Limb-Girdle Muscular Dystrophy.</a> Sci. Transl. Med. 4, (2012).</li><li>Tedesco, F. 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=Stem+cell-mediated+transfer+of+a+human+artificial+chromosome+ameliorates+muscular+dystrophy.">Stem cell-mediated transfer of a human artificial chromosome ameliorates muscular dystrophy.</a> Sci. Transl. Med. 3, (2011).</li><li>Lattanzi, L., 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+efficiency+myogenic+conversion+of+human+fibroblasts+by+adenoviral+vector-mediated+MyoD+gene+transfer.+An+alternative+strategy+for+ex+vivo+gene+therapy+of+primary+myopathies.">High efficiency myogenic conversion of human fibroblasts by adenoviral vector-mediated MyoD gene transfer. An alternative strategy for ex vivo gene therapy of primary myopathies.</a> J. Clin. Invest. 101, 2119-2128 (1998).</li><li>Chaouch, 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=Immortalized+skin+fibroblasts+expressing+conditional+MyoD+as+a+renewable+and+reliable+source+of+converted+human+muscle+cells+to+assess+therapeutic+strategies+for+muscular+dystrophies:+validation+of+an+exon-skipping+approach+to+restore+dystrophin+in+Duchenne+muscular+dystrophy+cells.">Immortalized skin fibroblasts expressing conditional MyoD as a renewable and reliable source of converted human muscle cells to assess therapeutic strategies for muscular dystrophies: validation of an exon-skipping approach to restore dystrophin in Duchenne muscular dystrophy cells.</a> Hum. Gene Ther. 20, 784-790 (2009).</li><li>Kimura, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell-lineage+regulated+myogenesis+for+dystrophin+replacement:+a+novel+therapeutic+approach+for+treatment+of+muscular+dystrophy.">Cell-lineage regulated myogenesis for dystrophin replacement: a novel therapeutic approach for treatment of muscular dystrophy.</a> Hum. Mol. Genet. 17, 2507-2517 (2008).</li><li>Yamanaka, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induced+pluripotent+stem+cells:+past,+present,+and+future.">Induced pluripotent stem cells: past, present, and future.</a> Cell Stem Cell. 10, 678-684 (2012).</li><li>Wu, S. M., Hochedlinger, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Harnessing+the+potential+of+induced+pluripotent+stem+cells+for+regenerative+medicine.">Harnessing the potential of induced pluripotent stem cells for regenerative medicine.</a> Nat. Cell Biol. 13, 497-505 (2011).</li></ol>

iPSCs can be expanded indefinitely while preserving their self-renewal potential and thus be directed to differentiate into a broad range of cell lineages12. For this and other reasons iPSC-derived stem/progenitor cells are considered a promising source for autologous gene and cell therapy approaches13. A previously published work from the Authors reported the generation of mouse and human myogenic progenitors from iPSCs with a phenotype similar to that of pericyte-derived MABs (IDEMs) and their eff...

Mesoangioblasts (MABs) are vessel-associated muscle progenitors derived from a subset of pericytes1-3. The main advantage of MABs over canonical muscle progenitors such as satellite cells4 resides in their ability to cross the vessel wall when delivered intra-arterial and hence contribute to skeletal muscle regeneration in cell therapy protocols. This feature has been evaluated and confirmed in both murine and canine models of muscular dystrophy1,5,6. These preclinical studies have built the foundations for a first-in-man phase I/II clinical trial based upon intra-arterial transplantation of donor HLA-identical MABs in children with Duchenne muscular dystrophy (EudraCT no. 2011-000176-33; currently on going at San Raffaele Hospital of Milan, Italy). One of the main hurdles of cell therapy approaches, where billions of cells are needed to treat the muscle of an entire body, is the limited proliferative potential of the &#34;medicinal product&#34; (the cells). Moreover it has been recently demonstrated that it is not possible to obtain MABs from patients affected by some forms of muscular dystrophies, as it occurs in limb-girdle muscular dystrophy 2D (LGMD2D; OMIM #608099)7.
To overcome these limitations, a protocol for deriving MAB-like stem/progenitor cells from human and murine iPSCs has been recently established7. This procedure generates easily expandable cell populations with a vascular gene signature and immunophenotype highly similar to adult muscle-derived MABs. Upon expression of the myogenic regulatory factor MyoD, both murine and human IDEMs (respectively MIDEMs and HIDEMs) undergo terminal skeletal muscle differentiation. To achieve this aim IDEMs can be transduced with vectors able to drive MyoD expression, either constitutively or in an inducible fashion8-10. A lentiviral vector containing MyoD cDNA fused with the estrogen receptor (MyoD-ER) is used, thus allowing its nuclear translocation upon tamoxifen (an estrogen analogue) administration11. This strategy results in the formation of hypertrophic multinucleated myotubes, with high efficiency7. Notably, IDEMs are nontumorigenic, can engraft and differentiate inside host muscles upon transplantation and can be genetically corrected using different vectors (e.g. lentiviruses or human artificial chromosomes), paving the way for future autologous therapeutic strategies. The derivation, characterization and transplantation of IDEMs have been described in the above publication7. This protocol paper details the assays performed to evaluate the in vitro myogenic differentiation of IDEMs and the subsequent outcome measurements to test the efficacy of their transplantation in mouse models of muscle regeneration.

<table border="1">
	<tbody>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>REAGENTS</td>
		</tr>
		<tr>
			<td>MegaCell DMEM</td>
			<td>Sigma</td>
			<td>M3942</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Sigma</td>
			<td>D5671</td>
			<td></td>
		</tr>
		<tr>
			<td>IMDM</td>
			<td>Sigma</td>
			<td>I3390</td>
			<td></td>
		</tr>
		<tr>
			<td>Horse serum</td>
			<td>Euroclone</td>
			<td>ECS0090L</td>
			<td></td>
		</tr>
		<tr>
			<td>Foetal Bovine Serum</td>
			<td>Lonza</td>
			<td>DE14801F</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS Calcium/Magnesium free</td>
			<td>Lonza</td>
			<td>BE17-516F</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glutammine</td>
			<td>Sigma</td>
			<td>G7513</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicilline/Streptomicin</td>
			<td>Sigma</td>
			<td>P0781</td>
			<td></td>
		</tr>
		<tr>
			<td>2-Mercaptoethanol</td>
			<td>Gibco</td>
			<td>31350-010</td>
			<td></td>
		</tr>
		<tr>
			<td>ITS (Insulin-Transferrin-Selenium)</td>
			<td>Gibco</td>
			<td>51500-056</td>
			<td></td>
		</tr>
		<tr>
			<td>Non-essential amino acid solution</td>
			<td>Sigma</td>
			<td>M7145</td>
			<td></td>
		</tr>
		<tr>
			<td>Fer-In-Sol</td>
			<td>Mead Johnson</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ferlixit</td>
			<td>Aventis</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Oleic Acid</td>
			<td>Sigma</td>
			<td>01257-10 mg</td>
			<td></td>
		</tr>
		<tr>
			<td>Linoleic Acid</td>
			<td>Sigma</td>
			<td>L5900-10 mg</td>
			<td></td>
		</tr>
		<tr>
			<td>Human bFGF</td>
			<td>Gibco</td>
			<td>AA 10-155</td>
			<td></td>
		</tr>
		<tr>
			<td>Grow factors-reduced Matrigel</td>
			<td>Becton Dickinson</td>
			<td>356230</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin</td>
			<td>Sigma</td>
			<td>T3924</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium heparin</td>
			<td>Mayne Pharma</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Trypan blue solution</td>
			<td>Sigma</td>
			<td>T8154</td>
			<td>HARMFUL</td>
		</tr>
		<tr>
			<td>Patent blue dye</td>
			<td>Sigma</td>
			<td>19, 821-8</td>
			<td></td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Sigma</td>
			<td>E-4884</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>TAAB</td>
			<td>P001</td>
			<td>HARMFUL</td>
		</tr>
		<tr>
			<td>Tamoxifen</td>
			<td>Sigma</td>
			<td>T5648</td>
			<td></td>
		</tr>
		<tr>
			<td>4-OH Tamoxifen</td>
			<td>Sigma</td>
			<td>H7904</td>
			<td></td>
		</tr>
		<tr>
			<td>pLv-CMV-MyoD-ER(T)</td>
			<td>Addgene</td>
			<td>26809</td>
			<td></td>
		</tr>
		<tr>
			<td>Cardiotoxin</td>
			<td>Sigma</td>
			<td>C9759</td>
			<td>HARMFUL</td>
		</tr>
		<tr>
			<td>Povidone iodine</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Tragachant gum</td>
			<td>MP biomedicals</td>
			<td>104792</td>
			<td></td>
		</tr>
		<tr>
			<td>Isopenthane</td>
			<td>VWR</td>
			<td>24,872,323</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue-tek OCT</td>
			<td>Sakura</td>
			<td>4583</td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>VWR</td>
			<td>27,480,294</td>
			<td></td>
		</tr>
		<tr>
			<td>Polarized glass slides</td>
			<td>Thermo</td>
			<td>J1800AMNZ</td>
			<td></td>
		</tr>
		<tr>
			<td>Eosin Y</td>
			<td>Sigma</td>
			<td>E4382</td>
			<td></td>
		</tr>
		<tr>
			<td>Hematoxylin</td>
			<td>Sigma</td>
			<td>HHS32</td>
			<td></td>
		</tr>
		<tr>
			<td>Masson&#39;s trichrome</td>
			<td>Bio-Optica</td>
			<td>04-010802</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse anti Myosin Heavy Chain antibody</td>
			<td>DSHB</td>
			<td>MF20</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse anti Lamin A/C antibody</td>
			<td>Novocastra</td>
			<td>NLC-LAM-A/C</td>
			<td></td>
		</tr>
		<tr>
			<td>4/11/13</td>
			<td>Cappel</td>
			<td>559762</td>
			<td></td>
		</tr>
		<tr>
			<td>Hoechst 33342</td>
			<td>Sigma fluka</td>
			<td>B2261</td>
			<td></td>
		</tr>
		<tr>
			<td>Rabbit anti Laminin antibody</td>
			<td>Sigma</td>
			<td>L9393</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>MATERIALS AND EQUIPMENT</td>
		</tr>
		<tr>
			<td>Adsorbable antibacteric suture 4-0</td>
			<td>Ethicon</td>
			<td>vcp310h</td>
			<td></td>
		</tr>
		<tr>
			<td>30G needle syringe</td>
			<td>BD</td>
			<td>324826</td>
			<td></td>
		</tr>
		<tr>
			<td>Treadmill</td>
			<td>Columbus instrument</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Steromicroscope</td>
			<td>Nikon</td>
			<td>SMZ800</td>
			<td></td>
		</tr>
		<tr>
			<td>Inverted microscope</td>
			<td>Leica</td>
			<td>DMIL LED</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane unit</td>
			<td>Harvad Apparatus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Fiber optics</td>
			<td>Euromecs (Holland)</td>
			<td>EK1</td>
			<td></td>
		</tr>
		<tr>
			<td>Heating pad</td>
			<td>Vet Tech</td>
			<td>C17A1</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpels</td>
			<td>Swann-Morton</td>
			<td>11REF050</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical forceps</td>
			<td>Fine Scientific Tools</td>
			<td></td>
			<td>5/45</td>
		</tr>
		<tr>
			<td>High temperature cauteriser</td>
			<td>Bovie Medical</td>
			<td>AA01</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>MEDIA COMPOSITION</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Media composition is detailed below. 
			HIDEMs growth medium:
			<ul>
				<li>MegaCell Dulbecco&#39;s Modified Eagle Medium (MegaCell DMEM)</li>
				<li>5% fetal bovine serum (FBS)</li>
				<li>2 mM glutamine</li>
				<li>0.1 mM &#946;-mercaptoethanol</li>
				<li>1% non essential amino acids</li>
				<li>5 ng / ml human basic fibroblast growth factor (bFGF)</li>
				<li>100 IU ml penicillin</li>
				<li>100 mg / ml streptomycin</li>
			</ul>
			Alternatively, if some of the above reagents are not available, HIDEMs can be grown in:
			<ul>
				<li>Iscove&#39;s Modified Dulbecco&#39;s Medium (IMDM)</li>
				<li>10 % FBS</li>
				<li>2 mM glutamine</li>
				<li>0.1 mM &#946;-mercaptoethanol</li>
				<li>1% Non essential amino acids (NEAA)</li>
				<li>1% ITS (insulin / transferrin / selenium)</li>
				<li>5 ng / ml human bFGF</li>
				<li>100 IU ml penicillin</li>
				<li>100 mg / ml streptomycin</li>
				<li>0.5 &#956;M oleic and linoleic acids</li>
				<li>1.5 &#956;M Fe2+ (Fer-In-Sol)</li>
				<li>0.12 &#956;M Fe3+ (Ferlixit)</li>
			</ul>
			MIDEMs growth medium:
			<ul>
				<li>DMEM</li>
				<li>20 % FBS</li>
				<li>2 mM glutamine</li>
				<li>5 ng / ml human bFGF</li>
				<li>100 IU ml penicillin</li>
				<li>100 mg / ml streptomycin</li>
			</ul>
			Differentiation medium:
			<ul>
				<li>DMEM</li>
				<li>2 % Horse Serum (HS)</li>
				<li>100 IU ml penicillin</li>
				<li>100 mg / ml streptomycin</li>
				<li>2 mM glutamine</li>
			</ul>
			 
			 
			</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>
Table 1. List of Reagents, Materials, Equipment, and Media.

transplantation of induced pluripotent stem cell-derived mesoangioblast-like myogenic progenitors in mouse models of muscle regeneration

Patient-derived iPSCs could be an invaluable source of cells for future autologous cell therapy protocols. iPSC-derived myogenic stem/progenitor cells similar to pericyte-derived mesoangioblasts (iPSC-derived mesoangioblast-like stem/progenitor cells: IDEMs) can be established from iPSCs generated from patients affected by different forms of muscular dystrophy. Patient-specific IDEMs can be genetically corrected with different strategies (e.g. lentiviral vectors, human artificial chromosomes) and enhanced in their myogenic differentiation potential upon overexpression of the myogenesis regulator MyoD. This myogenic potential is then assessed in vitro with specific differentiation assays and analyzed by immunofluorescence. The regenerative potential of IDEMs is further evaluated in vivo, upon intramuscular and intra-arterial transplantation in two representative mouse models displaying acute and chronic muscle regeneration. The contribution of IDEMs to the host skeletal muscle is then confirmed by different functional tests in transplanted mice. In particular, the amelioration of the motor capacity of the animals is studied with treadmill tests. Cell engraftment and differentiation are then assessed by a number of histological and immunofluorescence assays on transplanted muscles. Overall, this paper describes the assays and tools currently utilized to evaluate the differentiation capacity of IDEMs, focusing on the transplantation methods and subsequent outcome measures to analyze the efficacy of cell transplantation.

The reported representative results follow the main in vitro/in vivo assays depicted in the workflow in Figure 1. 48 hr after 4OH-tamoxifen administration MyoD-positive nuclei are identifiable within MyoD-ER transduced IDEMs in culture (Figure 2A). The cells then fuse and differentiate into multinucleated myotubes (Figure 2B). When transplanted intramuscularly into a murine model of acute muscle injury, IDEMs contribute to tissue regeneration (Figure 3</...

Watch this Scientific Journal Video about Transplantation of Induced Pluripotent Stem Cell-derived Mesoangioblast-like Myogenic Progenitors in Mouse Models of Muscle Regeneration at JoVE.com

Transplantation of Induced Pluripotent Stem Cell-derived Mesoangioblast-like Myogenic Progenitors in Mouse Models of Muscle Regeneration

Induced pluripotent stem cell (iPSC)-derived myogenic progenitors are promising candidates for cell therapy strategies to treat muscular dystrophies. This protocol describes transplantation and functional measurements required to evaluate the engraftment and differentiation of iPSC-derived mesoangioblasts (a type of muscle progenitors) in mouse models of acute and chronic muscle regeneration.

Patient-derived iPSCs could be an invaluable source of cells for future autologous cell therapy protocols. iPSC-derived myogenic stem/progenitor cells ...

transplantation-induced-pluripotent-stem-cell-derived-mesoangioblast

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9.3K Views.  University College London. Induced pluripotent stem cell (iPSC)-derived myogenic progenitors are promising candidates for cell therapy strategies to treat muscular dystrophies. This protocol describes transplantation and functional measurements required to evaluate the engraftment and differentiation of iPSC-derived mesoangioblasts (a type of muscle progenitors) in mouse models of acute and chronic muscle regeneration.

Video: Transplantation of Induced Pluripotent Stem Cell-derived Mesoangioblast-like Myogenic Progenitors in Mouse Models of Muscle Regeneration

Use of Human Perivascular Stem Cells for Bone Regeneration

Human perivascular stem cells (PSCs) can be isolated in sufficient numbers from multiple tissues for purposes of skeletal tissue engineering1-3. PSCs are a FACS-sorted population of 'pericytes' (CD146+CD34-CD45-) and 'adventitial cells' (CD146-CD34+CD45-), each of which we have previously reported to have properties of mesenchymal stem cells. PSCs, like MSCs, are able to undergo osteogenic differentiation, as well as secrete pro-osteogenic cytokines1,2. In the present protocol, we demonstrate the osteogenicity of PSCs in several animal models including a muscle pouch implantation in SCID (severe combined immunodeficient) mice, a SCID mouse calvarial defect and a femoral segmental defect (FSD) in athymic rats. The thigh muscle pouch model is used to assess ectopic bone formation. Calvarial defects are centered on the parietal bone and are standardly 4 mm in diameter (critically sized)8. FSDs are bicortical and are stabilized with a polyethylene bar and K-wires4. The FSD described is also a critical size defect, which does not significantly heal on its own4. In contrast, if stem cells or growth factors are added to the defect site, significant bone regeneration can be appreciated. The overall goal of PSC xenografting is to demonstrate the osteogenic capability of this cell type in both ectopic and orthotopic bone regeneration models.

Human perivascular stem cells (PSCs) are a novel stem cell class for skeletal tissue regeneration similar to mesenchymal stem cells (MSCs). PSCs can be isolated by FACS (fluorescence activated cell sorting) from adipose tissue procured during standard liposuction procedures, then combined with an osteoinductive scaffold to achieve bone formation in vivo.

Human perivascular stem cells (PSCs) can be isolated in sufficient numbers from multiple tissues for purposes of skeletal tissue engineering1-3. PSCs are ...

Development, Expansion, and In vivo Monitoring of Human NK Cells from Human Embryonic Stem Cells (hESCs) and Induced Pluripotent Stem Cells (iPSCs)

We present a method for deriving natural killer (NK) cells from undifferentiated hESCs and iPSCs using a feeder-free approach. This method gives rise to high levels of NK cells after 4 weeks culture and can undergo further 2-log expansion with artificial antigen presenting cells. hESC- and iPSC-derived NK cells developed in this system have a mature phenotype and function. The production of large numbers of genetically modifiable NK cells is applicable for both basic mechanistic as well as anti-tumor studies. Expression of firefly luciferase in hESC-derived NK cells allows a non-invasive approach to follow NK cell engraftment, distribution, and function. We also describe a dual-imaging scheme that allows separate monitoring of two different cell populations to more distinctly characterize their interactions in vivo. This method of derivation, expansion, and dual in vivo imaging provides a reliable approach for producing NK cells and their evaluation which is necessary to improve current NK cell adoptive therapies.

Development, Expansion, and In vivo Monitoring of Human NK Cells from Human Embryonic Stem Cells hESCs and Induced Pluripotent Stem Cells iPSCs

This protocol describes the development, expansion, and in vivo imaging of NK cells derived from hESCs and iPSCs.

We present a method for deriving natural killer (NK) cells from undifferentiated hESCs and iPSCs using a feeder-free approach. This method gives rise to ...

Patterning the Geometry of Human Embryonic Stem Cell Colonies on Compliant Substrates to Control Tissue-Level Mechanics

Human embryonic stem cells demonstrate a unique ability to respond to morphogens in vitro by self-organizing patterns of cell fate specification that correspond to primary germ layer formation during embryogenesis. Thus, these cells represent a powerful tool with which to examine the mechanisms that drive early human development. We have developed a method to culture human embryonic stem cells in confined colonies on compliant substrates that provides control over both the geometry of the colonies and their mechanical environment in order to recapitulate the physical parameters that underlie embryogenesis. The key feature of this method is the ability to generate polyacrylamide hydrogels with defined patterns of extracellular matrix ligand at the surface to promote cell attachment. This is achieved by fabricating stencils with the desired geometric patterns, using these stencils to create patterns of extracellular matrix ligand on glass coverslips, and transferring these patterns to polyacrylamide hydrogels during polymerization. This method is also compatible with traction force microscopy, allowing the user to measure and map the distribution of cell-generated forces within the confined colonies. In combination with standard biochemical assays, these measurements can be used to examine the role mechanical cues play in fate specification and morphogenesis during early human development.

Extracellular matrix ligands can be patterned onto polyacrylamide hydrogels to enable the culture of human embryonic stem cells in confined colonies on compliant substrates. This method can be combined with traction force microscopy and biochemical assays to examine the interplay between tissue geometry, cell-generated forces, and fate specification.

Human embryonic stem cells demonstrate a unique ability to respond to morphogens in vitro by self-organizing patterns of cell fate specification that ...

Isolation of Adult Human Dermal Fibroblasts from Abdominal Skin and Generation of Induced Pluripotent Stem Cells Using a Non-Integrating Method

Induced pluripotent stem cells (iPSCs) could be considered, to date, a promising source of pluripotent cells for the management of currently untreatable diseases, for the reconstitution and regeneration of injured tissues and for the development of new drugs. Despite all the advantages related to the use of iPSCs, such as the low risk of rejection, the lessened ethical issues, and the possibility to obtain them from both young and old patients without any difference in their reprogramming potential, problems to overcome are still numerous. In fact, cell reprogramming conducted with viral and integrating viruses can cause infections and the introduction of required genes can induce a genomic instability of the recipient cell, impairing their use in clinic. In particular, there are many concerns about the use of c-Myc gene, well-known from several studies for its mutation-inducing activity. Fibroblasts have emerged as the suitable cell population for cellular reprogramming as they are easy to isolate and culture and are harvested by a minimally invasive skin punch biopsy. The protocol described here provides a detailed step-by-step description of the whole procedure, from sample processing to obtain cell cultures, choice of reagents and supplies, cleaning and preparation, to cell reprogramming by the means of a commercial non-modified RNAs (NM-RNAs)-based reprogramming kit. The chosen reprogramming kit allows an effective reprogramming of human dermal fibroblast to iPSCs and small colonies can be seen as early as 24 h after the first transfection, even with modifications with the respect to the standard datasheet. The reprogramming procedure used in this protocol offers the advantage of a safe reprogramming, without the risk of infections caused by viral vector-based methods, reduces the cellular defense mechanisms, and allows the generation of xeno-free iPSCs, all critical features that are mandatory for further clinical applications.

Cell reprogramming requires the introduction of key genes, which regulate and maintain the pluripotent cell state. The protocol described enables the formation of induced pluripotent stem cells (iPSCs) colonies from human dermal fibroblasts without viral/integrating methods but using non-modified RNAs (NM-RNAs) combined with immune evasion factors reducing cellular defense mechanisms.

Induced pluripotent stem cells (iPSCs) could be considered, to date, a promising source of pluripotent cells for the management of currently untreatable ...

Guided Differentiation of Mature Kidney Podocytes from Human Induced Pluripotent Stem Cells Under Chemically Defined Conditions

Kidney disease affects more than 10% of the global population and costs billions of dollars in federal expenditures. The most severe forms of kidney disease and eventual end-stage renal failure are often caused by the damage to the glomerular podocytes, which are the highly specialized epithelial cells that function together with endothelial cells and the glomerular basement membrane to form the kidney&#8217;s filtration barrier. Advances in renal medicine have been hindered by the limited availability of primary tissues and the lack of robust methods for the derivation of functional human kidney cells, such as podocytes. The ability to derive podocytes from renewable sources, such as stem cells, could help advance current understanding of the mechanisms of human kidney development and disease, as well as provide new tools for therapeutic discovery. The goal of this protocol was to develop a method to derive mature, post-mitotic podocytes from human induced pluripotent stem (hiPS) cells with high efficiency and specificity, and under chemically defined conditions. The hiPS cell-derived podocytes produced by this method express lineage-specific markers (including nephrin, podocin, and Wilm&#8217;s Tumor 1) and exhibit the specialized morphological characteristics (including primary and secondary foot processes) associated with mature and functional podocytes. Intriguingly, these specialized features are notably absent in the immortalized podocyte cell line widely used in the field, which suggests that the protocol described herein produces human kidney podocytes that have a developmentally more mature phenotype than the existing podocyte cell lines typically used to study human kidney biology.

Presented here is a chemically defined protocol for the derivation of human kidney podocytes from induced pluripotent stem cells with high efficiency (&#62;90%) and independent of genetic manipulations or subpopulation selection. This protocol produces the desired cell type within 26 days and could be useful for nephrotoxicity testing and disease modeling.

Kidney disease affects more than 10% of the global population and costs billions of dollars in federal expenditures. The most severe forms of kidney ...

Single-Cell Optical Action Potential Measurement in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Conventional intracellular microelectrode techniques to quantify cardiomyocyte electrophysiology are extremely complex, labor intensive, and typically carried out in low throughput. Rapid and ongoing expansion of induced pluripotent stem cell (iPSC) technology presents a new standard in cardiovascular research and alternate methods are now necessary to increase throughput of electrophysiological data at a single cell level. VF2.1Cl is a recently derived voltage sensitive dye which provides a rapid single channel, high magnitude response to fluctuations in membrane potential. It possesses kinetics superior to those of other existing voltage indicators and makes available functional data equivalent to that of traditional microelectrode techniques. Here, we demonstrate simplified, non-invasive action potential characterization in externally paced human iPSC derived cardiomyocytes using a modular and highly affordable photometry system.

Here we describe optical acquisition and characterization of action potentials from induced pluripotent stem cell derived cardiomyocytes using a high-speed modular photometry system.

Conventional intracellular microelectrode techniques to quantify cardiomyocyte electrophysiology are extremely complex, labor intensive, and typically ...

Isogenic Kidney Glomerulus Chip Engineered from Human Induced Pluripotent Stem Cells

Chronic kidney disease (CKD) affects 15% of the U.S. adult population, but the establishment of targeted therapies has been limited by the lack of functional models that can accurately predict human biological responses and nephrotoxicity. Advancements in kidney precision medicine could help overcome these limitations. However, previously established in vitro models of the human kidney glomerulus-the primary site for blood filtration and a key target of many diseases and drug toxicities-typically employ heterogeneous cell populations with limited functional characteristics and unmatched genetic backgrounds. These characteristics significantly limit their application for patient-specific disease modeling and therapeutic discovery. 
This paper presents a protocol that integrates human induced pluripotent stem (iPS) cell-derived glomerular epithelium (podocytes) and vascular endothelium from a single patient to engineer an isogenic and vascularized microfluidic kidney glomerulus chip. The resulting glomerulus chip is comprised of stem cell-derived endothelial and epithelial cell layers that express lineage-specific markers, produce basement membrane proteins, and form a tissue-tissue interface resembling the kidney's glomerular filtration barrier. The engineered glomerulus chip selectively filters molecules and recapitulates drug-induced kidney injury. The ability to reconstitute the structure and function of the kidney glomerulus using isogenic cell types creates the opportunity to model kidney disease with patient specificity and advance the utility of organs-on-chips for kidney precision medicine and related applications.

Presented here is a protocol to engineer a personalized organ-on-a-chip system that recapitulates the structure and function of the kidney glomerular filtration barrier by integrating genetically matched epithelial and vascular endothelial cells differentiated from human induced pluripotent stem cells. This bioengineered system can advance kidney precision medicine and related applications.

Chronic kidney disease (CKD) affects 15% of the U.S. adult population, but the establishment of targeted therapies has been limited by the lack of ...

Evaluation of Cardiac Contractility Modulation Therapy in 2D Human Stem Cell-Derived Cardiomyocytes

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are currently being explored for multiple in vitro applications and have been used in regulatory submissions. Here, we extend their use to cardiac medical device safety or performance assessments. We developed a novel method to evaluate cardiac medical device contractile properties in robustly contracting 2D hiPSC-CMs monolayers plated on a flexible extracellular matrix (ECM)-based hydrogel substrate. This tool enables the quantification of the effects of cardiac electrophysiology device signals on human cardiac function (e.g., contractile properties) with standard laboratory equipment. The 2D hiPSC-CM monolayers were cultured for 2-4 days on a flexible hydrogel substrate in a 48-well format.
The hiPSC-CMs were exposed to standard cardiac contractility modulation (CCM) medical device electrical signals and compared to control (i.e., pacing only) hiPSC-CMs. The baseline contractile properties of the 2D hiPSC-CMs were quantified by video-based detection analysis based on pixel displacement. The CCM-stimulated 2D hiPSC-CMs plated on the flexible hydrogel substrate displayed significantly enhanced contractile properties relative to baseline (i.e., before CCM stimulation), including an increased peak contraction amplitude and accelerated contraction and relaxation kinetics. Furthermore, the utilization of the flexible hydrogel substrate enables the multiplexing of the video-based cardiac-excitation contraction coupling readouts (i.e., electrophysiology, calcium handling, and contraction) in healthy and diseased hiPSC-CMs. The accurate detection and quantification of the effects of cardiac electrophysiological signals on human cardiac contraction is vital for cardiac medical device development, optimization, and de-risking. This method enables the robust visualization and quantification of the contractile properties of the cardiac syncytium, which should be valuable for nonclinical cardiac medical device safety or effectiveness testing. This paper describes, in detail, the methodology to generate 2D hiPSC-CM hydrogel substrate monolayers.

Here, we demonstrate a non-invasive cardiac medical device contractility evaluation method using 2D human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) monolayers, plated on a flexible substrate, coupled with video-based microscopy. This tool will be useful for the in vitro evaluation of the contractile properties of cardiac electrophysiology devices.

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are currently being explored for multiple in vitro applications and have been used ...

Generation of Human Blood Vessel Organoids from Pluripotent Stem Cells

An organoid is defined as an engineered multicellular in vitro tissue that mimics its corresponding in vivo organ such that it can be used to study defined aspects of that organ in a tissue culture dish. The breadth and application of human pluripotent stem cell (hPSC)-derived organoid research have advanced significantly to include the brain, retina, tear duct, heart, lung, intestine, pancreas, kidney, and blood vessels, among several other tissues. The development of methods for the generation of human microvessels, specifically, has opened the way for modeling human blood vessel development and disease in vitro and for the testing and analysis of new drugs or tissue tropism in virus infections, including SARS-CoV-2. Complex and lengthy protocols lacking visual guidance hamper the reproducibility of many stem cell-derived organoids. Additionally, the inherent stochasticity of organoid formation processes and self-organization necessitates the generation of optical protocols to advance the understanding of cell fate acquisition and programming. Here, a visually guided protocol is presented for the generation of 3D human blood vessel organoids (BVOs) engineered from hPSCs. Presenting a continuous basement membrane, vascular endothelial cells, and organized articulation with mural cells, BVOs exhibit the functional, morphological, and molecular features of human microvasculature. BVO formation is initiated through aggregate formation, followed by mesoderm and vascular induction. Vascular maturation and network formation are initiated and supported by embedding aggregates in a 3D collagen and solubilized basement membrane matrix. Human vessel networks form within 2-3 weeks and can be further grown in scalable culture systems. Importantly, BVOs transplanted into immunocompromised mice anastomose with the endogenous mouse circulation and specify into functional arteries, veins, and arterioles. The present visually guided protocol will advance human organoid research, particularly in relation to blood vessels in normal development, tissue vascularization, and disease.

This protocol describes the generation of self-organizing blood vessels from human pluripotent and induced pluripotent stem cells. These blood vessel networks exhibit an extensive and connected endothelial network surrounded by pericytes, smooth muscle actin, and a continuous basement membrane.

An organoid is defined as an engineered multicellular in vitro tissue that mimics its corresponding in vivo organ such that it can be used to study ...

Generation, High-Throughput Screening, and Biobanking of Human-Induced Pluripotent Stem Cell-Derived Cardiac Spheroids

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are of paramount importance for human cardiac disease modeling and therapeutics. We recently published a cost-effective strategy for the massive expansion of hiPSC-CMs in two dimensions (2D). Two major limitations are cell immaturity and a lack of three-dimensional (3D) arrangement and scalability in high-throughput screening (HTS) platforms. To overcome these limitations, the expanded cardiomyocytes form an ideal cell source for the generation of 3D cardiac cell culture and tissue engineering techniques. The latter holds great potential in the cardiovascular field, providing more advanced and physiologically relevant HTS. Here, we describe an HTS-compatible workflow with easy scalability for the generation, maintenance, and optical analysis of cardiac spheroids (CSs) in a 96-well-format. These small CSs are essential to fill the gap present in current in vitro disease models and/or generation for 3D tissue engineering platforms. The CSs present a highly structured morphology, size, and cellular composition. Furthermore, hiPSC-CMs cultured as CSs display increased maturation and several functional features of the human heart, such as spontaneous calcium handling and contractile activity. By automatization of the complete workflow, from the generation of CSs to functional analysis, we increase intra- and inter-batch reproducibility as demonstrated by high-throughput (HT) imaging and calcium handling analysis. The described protocol allows modeling of cardiac diseases and assessing drug/therapeutic effects at the single-cell level within a complex 3D cell environment in a fully automated HTS workflow. In addition, the study describes a straightforward procedure for long-term preservation and biobanking of whole-spheroids, thereby providing researchers the opportunity to create next-generation functional tissue storage. HTS combined with long-term storage will substantially contribute to translational research in a wide range of areas, including drug discovery and testing, regenerative medicine, and the development of personalized therapies.

Presented here is a set of protocols for the generation and cryopreservation of cardiac spheroids (CSs) from human-induced pluripotent stem cell-derived cardiomyocytes cultured in a high-throughput, multidimensional format. This three-dimensional model functions as a robust platform for disease modeling, high-throughput screenings, and maintains its functionality after cryopreservation.

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are of paramount importance for human cardiac disease modeling and therapeutics. We ...