Nous remercions le Dr Giulio Di Minin pour la dérivation des lignes phaESC et le Dr Remo Freimann pour l’opération de cytométrie du débit. Nous reconnaissons également Mme Michèle Schaffner et M. Thomas M. Hennek pour leur soutien technique au transfert d’embryons. Ces travaux ont été soutenus par la Fondation nationale suisse pour la science (31003A_152814/1).

<ol>
	<li>Ellegren, H., Galtier, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determinants+of+genetic+diversity.">Determinants of genetic diversity.</a> Nature Reviews: Genetics. 17 (7), 422-433 (2016).</li><li>Huijbers, I. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generating+genetically+modified+mice:+A+decision+guide.">Generating genetically modified mice: A decision guide.</a> Methods in Molecular Biology. 1642, 1-19 (2017).</li><li>Aizawa, E., Dumeau, C. E., Freimann, R., Di Minin, G., Wutz, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polyploidy+of+semi-cloned+embryos+generated+from+parthenogenetic+haploid+embryonic+stem+cells.">Polyploidy of semi-cloned embryos generated from parthenogenetic haploid embryonic stem cells.</a> PloS One. 15 (9), 0233072 (2020).</li><li>Li, 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=Androgenetic+haploid+embryonic+stem+cells+produce+live+transgenic+mice.">Androgenetic haploid embryonic stem cells produce live transgenic mice.</a> Nature. 490 (7420), 407-411 (2012).</li><li>Li, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Birth+of+fertile+bimaternal+offspring+following+intracytoplasmic+injection+of+parthenogenetic+haploid+embryonic+stem+cells.">Birth of fertile bimaternal offspring following intracytoplasmic injection of parthenogenetic haploid embryonic stem cells.</a> Cell Research. 26 (1), 135-138 (2016).</li><li>Wan, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parthenogenetic+haploid+embryonic+stem+cells+produce+fertile+mice.">Parthenogenetic haploid embryonic stem cells produce fertile mice.</a> Cell Research. 23 (11), 1330-1333 (2013).</li><li>Yang, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+genetically+modified+mice+by+oocyte+injection+of+androgenetic+haploid+embryonic+stem+cells.">Generation of genetically modified mice by oocyte injection of androgenetic haploid embryonic stem cells.</a> Cell. 149 (3), 605-617 (2012).</li><li>Zhong, 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=Parthenogenetic+haploid+embryonic+stem+cells+efficiently+support+mouse+generation+by+oocyte+injection.">Parthenogenetic haploid embryonic stem cells efficiently support mouse generation by oocyte injection.</a> Cell Research. 26 (1), 131-134 (2016).</li><li>Elling, U., 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=Forward+and+reverse+genetics+through+derivation+of+haploid+mouse+embryonic+stem+cells.">Forward and reverse genetics through derivation of haploid mouse embryonic stem cells.</a> Cell Stem Cell. 9 (6), 563-574 (2011).</li><li>Leeb, M., Wutz, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Derivation+of+haploid+embryonic+stem+cells+from+mouse+embryos.">Derivation of haploid embryonic stem cells from mouse embryos.</a> Nature. 479 (7371), 131-134 (2011).</li><li>Surani, M. A., Barton, S. C., Norris, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+reconstituted+mouse+eggs+suggests+imprinting+of+the+genome+during+gametogenesis.">Development of reconstituted mouse eggs suggests imprinting of the genome during gametogenesis.</a> Nature. 308 (5959), 548-550 (1984).</li><li>Li, Z. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+bimaternal+and+bipaternal+mice+from+hypomethylated+haploid+ESCs+with+imprinting+region+deletions.">Generation of bimaternal and bipaternal mice from hypomethylated haploid ESCs with imprinting region deletions.</a> Cell Stem Cell. 23 (5), 665-676 (2018).</li><li>Elling, U., 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=Derivation+and+maintenance+of+mouse+haploid+embryonic+stem+cells.">Derivation and maintenance of mouse haploid embryonic stem cells.</a> Nature Protocols. 14 (7), 1991-2014 (2019).</li><li>Ran, F. 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=Genome+engineering+using+the+CRISPR-Cas9+system.">Genome engineering using the CRISPR-Cas9 system.</a> Nature Protocols. 8 (11), 2281-2308 (2013).</li><li>Shuai, 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=Generation+of+mammalian+offspring+by+haploid+embryonic+stem+cells+microinjection.">Generation of mammalian offspring by haploid embryonic stem cells microinjection.</a> Current Protocols in Stem Cell Biology. 31, 1-15 (2014).</li><li>Lee, P. Y., Costumbrado, J., Hsu, C. Y., Kim, Y. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Agarose+gel+electrophoresis+for+the+separation+of+DNA+fragments.">Agarose gel electrophoresis for the separation of DNA fragments.</a> Journal of Visualized Experiments. (62), e3923 (2012).</li><li>Behringer, R., Gertsenstein, M., Nagy, K. V., Nagy, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Manipulating the Mouse Embryo: A Laboratory Manual. , (2014).</li><li>O'Neill, G. T., Rolfe, L. R., Kaufman, M. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Developmental+potential+and+chromosome+constitution+of+strontium-induced+mouse+parthenogenones.">Developmental potential and chromosome constitution of strontium-induced mouse parthenogenones.</a> Molecular Reproduction and Development. 30 (3), 214-219 (1991).</li><li>Campbell, K. H., McWhir, J., Ritchie, W. A., Wilmut, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sheep+cloned+by+nuclear+transfer+from+a+cultured+cell+line.">Sheep cloned by nuclear transfer from a cultured cell line.</a> Nature. 380 (6569), 64-66 (1996).</li><li>Wakayama, T., Perry, A. C., Zuccotti, M., Johnson, K. R., Yanagimachi, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Full-term+development+of+mice+from+enucleated+oocytes+injected+with+cumulus+cell+nuclei.">Full-term development of mice from enucleated oocytes injected with cumulus cell nuclei.</a> Nature. 394 (6691), 369-374 (1998).</li><li>Wilmut, I., Schnieke, A. E., McWhir, J., Kind, A. J., Campbell, K. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Viable+offspring+derived+from+fetal+and+adult+mammalian+cells.">Viable offspring derived from fetal and adult mammalian cells.</a> Nature. 385 (6619), 810-813 (1997).</li><li>Gurdon, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adult+frogs+derived+from+the+nuclei+of+single+somatic+cells.">Adult frogs derived from the nuclei of single somatic cells.</a> Developmental Biology. 4, 256-273 (1962).</li><li>Campbell, K. H., Alberio, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reprogramming+the+genome:+role+of+the+cell+cycle.">Reprogramming the genome: role of the cell cycle.</a> Reproduction Supplement. 61, 477-494 (2003).</li><li>Zhong, 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=CRISPR-Cas9-mediated+genetic+screening+in+mice+with+haploid+embryonic+stem+cells+carrying+a+guide+RNA+library.">CRISPR-Cas9-mediated genetic screening in mice with haploid embryonic stem cells carrying a guide RNA library.</a> Cell Stem Cell. 17 (2), 221-232 (2015).</li><li>Bai, 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=Targeted+genetic+screening+in+mice+through+haploid+embryonic+stem+cells+identifies+critical+genes+in+bone+development.">Targeted genetic screening in mice through haploid embryonic stem cells identifies critical genes in bone development.</a> PLoS Biology. 17 (7), 3000350 (2019).</li><li>Li, Q., 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=CRISPR-Cas9-mediated+base-editing+screening+in+mice+identifies+DND1+amino+acids+that+are+critical+for+primordial+germ+cell+development.">CRISPR-Cas9-mediated base-editing screening in mice identifies DND1 amino acids that are critical for primordial germ cell development.</a> Nature Cell Biology. 20 (11), 1315-1325 (2018).</li></ol>

Les auteurs n’ont rien à divulguer.

Le clonage des mammifères par transfert nucléaire de cellules somatiques (SCNT) a été pionnier dans les années 199019,20,21. Ces développements ont suivi des études de clonage menées 30 ans plus tôt chez lesamphibiens 22. Ce retard considérable reflète la difficulté de l’embryologie et de l’empreinte génomique chez les mammifères. Le développement du SCNT mammifère est à la base de l’application de l’haESC pour remplacer le sperme, qui est détaillée dans ce protocole.
La synchronisation du cycle cellulaire est un facteur important pour le succès de SCNT23. C’est également le cas pour l’injection de haESC dans ce protocole. L’introduction d’un génome donneur dans un receveur nécessite l’appariement des phases du cycle cellulaire afin d’éviter la rupture chromosomique ou les aneuploïdes qui abrogeraient le développement embryonnaire. Le semi-clonage a la complexité supplémentaire que deux génomes et un cytoplaste doivent être compatibles. Un rapport précédent a démontré que l’injection d’haESCs androgènes arrêtés en phase M a donné de meilleurs taux de développement d’embryons semi-clonés que l’injection d’haESCs de phase G1 dans les ovocytes7. Ce rapport suggère la phase M comme point de synchronisation approprié pour le semi-clonage. En conséquence, les phaESCs ont été mitotically arrêtés dans la metaphase avec la mémécolcine et injectés dans l’ooplasme des ovocytes de MII, qui ont été naturellement arrêtés dans la métaphe II de méiose. Fait important, l’arrestation en phase M peut être réalisée dans les ESC de souris avec une efficacité élevée, offrant une excellente synchronisation entre les cycles cellulaires des donneurs et des receveurs.
Pendant la mitose, la membrane nucléaire se décompose et un fuseau se forme auquel les chromosomes répliqués s’attachent. Après l’injection de DKO-phaESCs de phase M, les chromatides sœurs sont séparés en un corps pseudo polaire et le zygote7 (Figure 3E). Par conséquent, un seul ensemble de chromosomes provenant d’un DKO-phaESC contribue à l’embryon semi-cloné. Il est essentiel que les chromatismes sœurs des chromosomes DKO-phaESC puissent être correctement séparés après injection. La membrane plasmatique d’un DKO-phaESC intact empêche la ségrégation dans un corps pseudo polaire. Nous avons en effet observé de rares cas où la membrane plasmatique des DKO-phaESCs n’a pas été rompue, et les embryons ont montré des DKO-phaESCs intacts dans l’ooplasme après injection (figure 3D). Par conséquent, il faut prendre soin d’enlever la membrane plasmatique des DKO-phaESCs par pipetting. Pendant l’injection, il est tout aussi important d’éviter la perturbation du fuseau méiotique de l’ovocyte, qui pourrait conduire à des défauts de ségrégation chromosomique et induire une aneuploïde ainsi.
Chez les mammifères, l’empreinte génomique limite l’application de phaESCs comme substitut du sperme. Les haESCs parthénogénétiques possèdent une configuration maternelle des empreintes génomiques, tandis que le sperme possède une configuration paternelle. Par conséquent, la génération de chiots à terme n’a pas eu lieu après l’injection de phaESCs de type sauvage comme remplacement du sperme. Pour surmonter cette limitation, les suppressions des DMR IG- et H19- sont conçues en phaESCs. La modification de l’expression imprimée aux loci maternelles Igf2-H19 et Gtl2-Dlk1 est suffisante pour modifier la configuration des empreintes génomiques pour permettre la génération de souris semi-clonées avec une fréquence de plus de 5,1 %, basée sur des embryons transférés à 2 cellules. Ces observations suggèrent que le ciblage de deux gènes imprimés transforme le génome des phaESCs en une configuration paternelle fonctionnelle qui peut remplacer le sperme chez la souris. Néanmoins, une modification génétique permanente des phaESCs est nécessaire pour cette stratégie. Comme stratégie alternative, l’haESC androgène peut être considéré. Les haESCs androgènes sont dérivés du génome du sperme et possèdent des empreintes paternelles. Il y a eu des rapports que les haESCs androgènes de wildtype ont contribué en tant que remplacement de sperme pour produire des chiots à terme à une fréquence entre 1.3% et 1.9% des embryonstransférés 4,7,24. Des chiots à terme ont également été obtenus en injectant des haESCs androgènes avec des suppressions de l’IG- et h19-DMRs à une fréquence de 20,2% des embryons transférés à 2 cellules24. L’efficacité accrue du semi-clonage à l’aide d’haESCs androgènes modifiés est probablement parce que les empreintes peuvent devenir instables dans la culture. Les défauts d’impression sont corrigés par les suppressions génétiques des DMR critiques.
Compte tenu de la difficulté d’introduire des modifications génétiques directement dans les génomes des ovocytes ou des spermatozoïdes, les hésics sont un outil précieux pour manipuler les génomes parentaux séparément. L’utilisation d’haESCs comme substitut du sperme offre un avantage remarquable pour l’édition du génome dans la lignée germinale de la souris. Une étude récente a combiné l’édition du génome à base de CRISPR/Cas9 avec l’application d’haESCs pour la caractérisation des régions d’impression qui sont critiques pour le développement embryonnaire12. Cette étude a analysé le rôle des Rasgrf1-DMR en combinaison avec le H19-et IG-DMRs dans le développement de souris bimaternales, et la fonction de 7 DMR différents dans le développement de souris bipaternales. La méthode de substitution des HAESCs au sperme a servi de base à des approches de dépistage génétique pour identifier les acides aminés clés dans la protéine MDN1 dans le développement primordial des cellules germinales et pour identifier les gènesdans le développement osseux 24,25,26. Les études sur l’empreinte génomique et le dépistage génétique afin d’identifier les facteurs clés du développement embryonnaire sont des approches considérables pour l’application des HAESCs comme génomes gametiques.

Chez les mammifères, les gamètes sont les seules cellules qui transmettent des informations génétiques à la prochaine génération. La fusion d’un ovocyte et d’un spermatozoon forme un zygote diploïde qui se développe en animal adulte. Les mutations dans les génomes gametiques sont ainsi héritées par la progéniture et conduisent à des variations génétiques chez lesespèces 1. L’introduction de mutations dans la lignée germinale a été appliquée pour produire des animaux génétiquement modifiés pour diverses études biologiques, y compris la caractérisation de la fonction génétique et la modélisation des maladies. Les ovocytes et le spermatozoa sont des cellules en phase terminale différenciées et hautement spécialisées qui ont cessé la prolifération. Par conséquent, la modification directe des gamètes est techniquement difficile, et des approches spécialisées ont été développées. Des modifications génétiques peuvent être introduites dans la lignée germinale de la souris par l’injection d’ESCs génétiquement modifiés dans les blastocystes, où ils s’intègrent dans l’embryon en développement et colonisent la lignée germinale. En outre, la modification génétique des zygotes à l’aide d’approches d’édition du génome, y compris le système CRISPR/Cas9, est devenue largementadoptée 2.
Récemment, une approche exceptionnelle a été signalée, qui applique haESCs comme un substitut à un génome gametic3,4,5,6,7,8. Les HAESCs sont des lignées de cellules souches dérivées de la masse cellulaire interne des blastocystes haploïdes parthénogénétiques ou androgènes et possèdent un seul ensemble de chromosomes4,7,9,10. Il a été démontré que les haESCs parthénogénétiques et androgènes peuvent contribuer au génome des souris semi-clonées après injection intracytoplasmique dans les ovocytes. Contrairement à d’autres approches, les génomes des HAESC peuvent être directement modifiés en culture en raison de leur capacité d’auto-renouvellement. L’introduction de modifications génétiques dans la lignée germinale en remplaçant le sperme par des haESCs est une méthode importante pour les études biologiques. Il prévoit la possibilité de culturer et de manipuler séparément le génome maternel ou paternel, qui sont dérivés des haESCs parthénogénétiques ou androgènes, respectivement. Les HAESC peuvent ensuite être utilisés comme remplacement du génome gametique, ce qui est particulièrement avantageux pour les études d’empreinte génomique, d’expression spécifique à l’allèle et de processus spécifiques aux parents.
Chez la souris, des informations génomiques maternelles et paternelles sont nécessaires pour le développement normal del’embryon 11. Par conséquent, les petits à terme n’ont pas pu être obtenus lorsque des haESCs parthénogénétiques de type sauvage (phaESCs) ont été injectés pour remplacer le génome du sperme5,8. Pour surmonter le bloc de développement, l’empreinte génomique du génome maternel des haESCs parthénogénétiques doit être corrigée à une configuration paternelle. Ceci peut être réalisé par la manipulation des régions différemment méthylées (DMRs). À ce jour, des suppressions ciblées du H19-DMR, gtl2-Dlk1 IG-DMR, et Rasgrf1-DMR ont été étudiées pour réprimer les gènes exprimés maternellement dans les phaESCs3,5,8,12. Ces études ont démontré que les suppressions du H19-DMR et de l’IG-DMRsont suffisantes pour convertir une mère en une configuration d’empreinte paternelle qui peut remplacer les chromosomes du sperme. L’injection intracytoplasmique de phaESCs qui transportent les deux suppressions de DMR dans les ovocytes a donné des chiots semi-clonés avec une fréquence entre 5,1% et 15,5% des embryons transférés à 2 cellules.
Ce protocole est basé sur l’application de phaESCs avec suppressions de H19-DMR et IG-DMR, que nous qualions de phaESCs à double KO (DKO-phaESCs). Nous fournissons des instructions détaillées pour la modification de l’empreinte génomique dans les phaESCs pour établir des lignées DKO-phaESC, pour l’injection de DKO-phaESCs dans les ovocytes comme un substitut à un génome de sperme, pour la culture d’embryons semi-clonés aux blastocystes, et pour l’obtention de souris semi-clonées. Ce protocole est une référence pour les chercheurs qui nécessitent une manipulation précise et directe du génome paternel et de la génération d’embryons et de souris semi-clonés.

<table>
	<tbody>
		<tr>
			<td>1.5 mLTube</td>
			<td>Eppendorf</td>
			<td>0030 125.150</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>15 ml Tube</td>
			<td>Greiner Bio-One</td>
			<td>188271</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>12-well plate</td>
			<td>Thermo Scientific</td>
			<td>150628</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>24-well plate</td>
			<td>Thermo Scientific</td>
			<td>142475</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>6-well plate</td>
			<td>Thermo Scientific</td>
			<td>140675</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>96-well plate</td>
			<td>Thermo Scientific</td>
			<td>167008</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>&#946;-Mercaptoethanol</td>
			<td>Merck</td>
			<td>M6250</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>BSA fraction</td>
			<td>Gibco</td>
			<td>15260-037</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>CHIR 99021</td>
			<td>Axon</td>
			<td>1386</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>Demecolcine solution</td>
			<td>Merck</td>
			<td>D1925</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Gibco</td>
			<td>41965-039</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>DMEM / F-12</td>
			<td>Gibco</td>
			<td>11320-033</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>DR4 mouse</td>
			<td>The Jackson Laboratory</td>
			<td>3208</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Merck</td>
			<td>E5134</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>biowest</td>
			<td>S1810-500</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>Freezing medium</td>
			<td>amsbio</td>
			<td>11897</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>Gelatin</td>
			<td>Merck</td>
			<td>G1890</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>Hepes solution</td>
			<td>Gibco</td>
			<td>15630-056</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>Irradiated MEF</td>
			<td>Gibco</td>
			<td>A34966</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>LIF (Leukemia inhibitory factor)</td>
			<td>(Homemade)</td>
			<td>-</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>Lipofection reagent</td>
			<td>Invitrogen</td>
			<td>11668019</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>NDiff 227</td>
			<td>Takara</td>
			<td>Y40002</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>PD 0325901</td>
			<td>Axon</td>
			<td>1408</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>Pen Strep</td>
			<td>Gibco</td>
			<td>15140-122</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>piggyBac plasmid carrying a CAG-EGFP transgene</td>
			<td>Addgene</td>
			<td>#40973</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>piggyBac transposase plasmid</td>
			<td>System Biosciences</td>
			<td>PB210PA-1</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>pX330 plasmid</td>
			<td>Addgene</td>
			<td>#42230</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>pX458 plasmid</td>
			<td>Addgene</td>
			<td>#48138</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>Trypsin</td>
			<td>Gibco</td>
			<td>15090-046</td>
			<td>haESC culture</td>
		</tr>
		<tr>
			<td>DNA polymerase</td>
			<td>Thermo Scientific</td>
			<td>F549S</td>
			<td>Genotyping</td>
		</tr>
		<tr>
			<td>dNTP Mix</td>
			<td>Thermo Scientific</td>
			<td>R0192</td>
			<td>Genotyping</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Merck</td>
			<td>100983</td>
			<td>Genotyping</td>
		</tr>
		<tr>
			<td>Hydrochloric acid</td>
			<td>Merck</td>
			<td>100317</td>
			<td>Genotyping</td>
		</tr>
		<tr>
			<td>Isopropanol</td>
			<td>Merck</td>
			<td>109634</td>
			<td>Genotyping</td>
		</tr>
		<tr>
			<td>Proteinase K</td>
			<td>Axon</td>
			<td>A3830</td>
			<td>Genotyping</td>
		</tr>
		<tr>
			<td>SDS</td>
			<td>Merck</td>
			<td>71729</td>
			<td>Genotyping</td>
		</tr>
		<tr>
			<td>Sodium chloride</td>
			<td>Merck</td>
			<td>106404</td>
			<td>Genotyping</td>
		</tr>
		<tr>
			<td>ThermoMixer</td>
			<td>Epeendorf</td>
			<td>5384000012</td>
			<td>Genotyping</td>
		</tr>
		<tr>
			<td>Tris</td>
			<td>Merck</td>
			<td>T1503</td>
			<td>Genotyping</td>
		</tr>
		<tr>
			<td>5 mL Tube</td>
			<td>Falcon</td>
			<td>352063</td>
			<td>Flow cytometry</td>
		</tr>
		<tr>
			<td>5 mL Tube with cell strainer cap</td>
			<td>Falcon</td>
			<td>352235</td>
			<td>Flow cytometry</td>
		</tr>
		<tr>
			<td>Hoechst 33342</td>
			<td>Invitrogen</td>
			<td>H3570</td>
			<td>Flow cytometry</td>
		</tr>
		<tr>
			<td>MoFlo Astrios EQ</td>
			<td>Beckman Coulter</td>
			<td>B25982</td>
			<td>Flow cytometry</td>
		</tr>
		<tr>
			<td>1 mL syringe</td>
			<td>Codan</td>
			<td>62.1640</td>
			<td>Superovulation</td>
		</tr>
		<tr>
			<td>30-gauge 1/2 inch needle</td>
			<td>Merck</td>
			<td>Z192362-100EA</td>
			<td>Superovulation</td>
		</tr>
		<tr>
			<td>B6D2F1 mouse</td>
			<td>The Jackson Laboratory</td>
			<td>100006</td>
			<td>Superovulation</td>
		</tr>
		<tr>
			<td>hCG</td>
			<td>MSD animal health</td>
			<td>49451</td>
			<td>Superovulation</td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>Gibco</td>
			<td>10010015</td>
			<td>Superovulation</td>
		</tr>
		<tr>
			<td>PMSG</td>
			<td>Avivasysbio</td>
			<td>OPPA1037 5000 IU</td>
			<td>Superovulation</td>
		</tr>
		<tr>
			<td>10-cm dish</td>
			<td>Thermo Scientific</td>
			<td>150350</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>4-well plate</td>
			<td>Thermo Scientific</td>
			<td>179830</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>50 mL tube</td>
			<td>Greiner Bio-One</td>
			<td>227261</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>6 cm dish</td>
			<td>Thermo Scientific</td>
			<td>150288</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>Center-well dish</td>
			<td>Corning</td>
			<td>3260</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>Digital rocker</td>
			<td>Thermo Scientific</td>
			<td>88880020</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>EGTA</td>
			<td>AppliChem</td>
			<td>A0878</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>Hyaluronidase</td>
			<td>Merck</td>
			<td>H4272</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>KSOM</td>
			<td>Merck</td>
			<td>MR-020P-5F</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>M16 medium</td>
			<td>Merck</td>
			<td>M7292</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>M2 medium</td>
			<td>Merck</td>
			<td>M7167</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>Mineral oil</td>
			<td>Merck</td>
			<td>M8410</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>Glass capillary</td>
			<td>Merck</td>
			<td>P1049-1PAK</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>Stereomicroscope</td>
			<td>Nikon</td>
			<td>SMZ745</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>Strontium chloride</td>
			<td>Merck</td>
			<td>13909</td>
			<td>Embryo manipulation</td>
		</tr>
		<tr>
			<td>5ml syringe</td>
			<td>Codan</td>
			<td>62.5607</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>Borosilicate glass cappilary</td>
			<td>Science product</td>
			<td>GB100T-8P</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>CellTram 4r Oil</td>
			<td>Eppendorf</td>
			<td>5196000030</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>Fluorinert FC-770</td>
			<td>Merck</td>
			<td>F3556</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>Holding pipette</td>
			<td>BioMedical Instruments</td>
			<td>-</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>Inverted microscope</td>
			<td>Nikon</td>
			<td>Eclipse Ti-U</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>Microforge</td>
			<td>Narishige</td>
			<td>MF-900</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>Microinjection pipette</td>
			<td>BioMedical Instruments</td>
			<td>-</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>Microlaoder tips</td>
			<td>Eppendorf</td>
			<td>5252 956.003</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>Micromanipulaor arms</td>
			<td>Narishige</td>
			<td>NT-88-V3</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>Micropipette puller</td>
			<td>Sutter Instrument</td>
			<td>P-1000</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>PiezoXpert</td>
			<td>Eppendorf</td>
			<td>5194000016</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>PVP (Polyvinylpyrrolidine)</td>
			<td>Merck</td>
			<td>PVP360</td>
			<td>Microinjection</td>
		</tr>
		<tr>
			<td>Syringe filter</td>
			<td>SARSTEDT</td>
			<td>83.1826.001</td>
			<td>Microinjection</td>
		</tr>
	</tbody>
</table>

application of mouse parthenogenetic haploid embryonic stem cells as a substitute of sperm

Dans les organismes ayant une reproduction sexuelle, les cellules germinales sont la source de cellules totipotentes qui se développent en nouveaux individus. Chez la souris, la fécondation d’un ovocyte par un spermatozoon crée un zygote totipotent. Récemment, plusieurs publications ont rapporté que les cellules souches embryonnaires haploïdes (HAESCs) peuvent remplacer les génomes gametiques et contribuer aux embryons, qui se développent en souris. Ici, nous présentons un protocole pour appliquer les haESCs parthénogénétiques comme substitut du sperme pour construire des embryons par injection intracytoplasmique dans les ovocytes. Ce protocole consiste en des étapes de préparation des HAESCs comme substitut du sperme, pour l’injection de chromosomes haESC dans les ovocytes, et pour la culture d’embryons semi-clonés. Les embryons peuvent donner des souris semi-clonées fertiles après le transfert d’embryons. L’utilisation des haESCs comme substitut de sperme facilite l’édition du génome dans la lignée germinale, les études sur le développement embryonnaire et l’étude de l’empreinte génomique.

Watch this Scientific Journal Video about Application of Mouse Parthenogenetic Haploid Embryonic Stem Cells as a Substitute of Sperm at JoVE.com

Application of Mouse Parthenogenetic Haploid Embryonic Stem Cells as a Substitute of Sperm

Cet article vise à démontrer l’utilisation de cellules souches embryonnaires haploïdes parthénogénétiques comme substitut au sperme pour la construction d’embryons semi-clonés.

Application des cellules souches embryonnaires haploïdes parthénogénétiques de souris comme substitut du sperme

In organisms with sexual reproduction, germ cells are the source of totipotent cells that develop into new individuals. In mice, fertilization of an ...

application-mouse-parthenogenetic-haploid-embryonic-stem-cells-as

Research

JoVE Journal

Developmental Biology

4.5K vues.  ETH Zurich. Cet article vise à démontrer l’utilisation de cellules souches embryonnaires haploïdes parthénogénétiques comme substitut au sperme pour la construction d’embryons semi-clonés.

Vidéo: Application of Mouse Parthenogenetic Haploid Embryonic Stem Cells as a Substitute of Sperm

Derivation of Cardiac Progenitor Cells from Embryonic Stem Cells

Cardiac progenitor cells (CPCs) have the capacity to differentiate into cardiomyocytes, smooth muscle cells (SMC), and endothelial cells and hold great promise in cell therapy against heart disease. Among various methods to isolate CPCs, differentiation of embryonic stem cell (ESC) into CPCs attracts great attention in the field since ESCs can provide unlimited cell source. As a result, numerous strategies have been developed to derive CPCs from ESCs. In this protocol, differentiation and purification of embryonic CPCs from both mouse and human ESCs is described. Due to the difficulty of using cell surface markers to isolate embryonic CPCs, ESCs are engineered with fluorescent reporters activated by CPC-specific cre recombinase expression. Thus, CPCs can be enriched by fluorescence-activated cell sorting (FACS). This protocol illustrates procedures to form embryoid bodies (EBs) from ESCs for CPC specification and enrichment. The isolated CPCs can be subsequently cultured for cardiac lineage differentiation and other biological assays. This protocol is optimized for robust and efficient derivation of CPCs from both mouse and human ESCs.

In this protocol, derivation of cardiac progenitor cells from both mouse and human embryonic stem cells will be illustrated. A major strategy in this protocol is to enrich cardiac progenitor cells with flow cytometry using fluorescent reporters engineered into the embryonic stem cell lines.

Dérivation des cellules cardiaques progénitrices de cellules souches embryonnaires

Cardiac progenitor cells (CPCs) have the capacity to differentiate into cardiomyocytes, smooth muscle cells (SMC), and endothelial cells and hold great ...

Recherche

Biologie du développement

Neural Differentiation of Mouse Embryonic Stem Cells in Serum-free Monolayer Culture

The ability to differentiate mouse embryonic stem cells (ESC) to neural progenitors allows the study of the mechanisms controlling neural specification as well as the generation of mature neural cell types for further study. In this protocol we describe a method for the differentiation of ESC to neural progenitors using serum-free, monolayer culture. The method is scalable, efficient and results in production of ~70% neural progenitor cells within 4 - 6 days. It can be applied to ESC from various strains grown under a variety of conditions. Neural progenitors can be allowed to differentiate further into functional neurons and glia or analyzed by microscopy, flow cytometry or molecular techniques. The differentiation process is amenable to time-lapse microscopy and can be combined with the use of reporter lines to monitor the neural specification process. We provide detailed instructions on media preparation and cell density optimization to allow the process to be applied to most ESC lines and a variety of cell culture vessels.

This protocol describes in detail the method for generating neural progenitors from embryonic stem cells using a serum-free monolayer method. These progenitors can be used to derive mature neural cell types or to study the process of neural specification and is amenable to multiwell format scaling for compound screening.

Différenciation neurale des souris de cellules souches embryonnaires dans le sérum sans culture monocouche

The ability to differentiate mouse embryonic stem cells (ESC) to neural progenitors allows the study of the mechanisms controlling neural specification as ...

Generating CRISPR/Cas9 Mediated Monoallelic Deletions to Study Enhancer Function in Mouse Embryonic Stem Cells

Enhancers control cell identity by regulating tissue-specific gene expression in a position and orientation independent manner. These enhancers are often located distally from the regulated gene in intergenic regions or even within the body of another gene. The position independent nature of enhancer activity makes it difficult to match enhancers with the genes they regulate. Deletion of an enhancer region provides direct evidence for enhancer activity and is the gold standard to reveal an enhancer's role in endogenous gene transcription. Conventional homologous recombination based deletion methods have been surpassed by recent advances in genome editing technology which enable rapid and precisely located changes to the genomes of numerous model organisms. CRISPR/Cas9 mediated genome editing can be used to manipulate the genome in many cell types and organisms rapidly and cost effectively, due to the ease with which Cas9 can be targeted to the genome by a guide RNA from a bespoke expression plasmid. Homozygous deletion of essential gene regulatory elements might lead to lethality or alter cellular phenotype whereas monoallelic deletion of transcriptional enhancers allows for the study of cis-regulation of gene expression without this confounding issue. Presented here is a protocol for CRISPR/Cas9 mediated deletion in F1 mouse embryonic stem (ES) cells (Mus musculus129 x Mus castaneus). Monoallelic deletion, screening and expression analysis is facilitated by single nucleotide polymorphisms (SNP) between the two alleles which occur on average every 125 bp in these cells.

Experimental validation of enhancer activity is best approached by loss-of-function analysis. Presented here is an efficient protocol that uses CRISPR/Cas9 mediated deletion to study allele-specific regulation of gene transcription in F1 ES cells which contain a hybrid genome (Mus musculus129 x Mus castaneus).

CRISPR Génération / cas9 Mediated monoallélique Suppressions pour étudier la fonction Enhancer dans souris cellules souches embryonnaires

Enhancers control cell identity by regulating tissue-specific gene expression in a position and orientation independent manner. These enhancers are often ...

Isolation of Murine Embryonic Hemogenic Endothelial Cells

The specification of hemogenic endothelial cells from embryonic vascular endothelium occurs during brief developmental periods within distinct tissues, and is necessary for the emergence of definitive HSPC from the murine extra embryonic yolk sac, placenta, umbilical vessels, and the embryonic aorta-gonad-mesonephros (AGM) region. The transient nature and small size of this cell population renders its reproducible isolation for careful quantification and experimental applications technically difficult. We have established a fluorescence-activated cell sorting (FACS)-based protocol for simultaneous isolation of hemogenic endothelial cells and HSPC during their peak generation times in the yolk sac and AGM. We demonstrate methods for dissection of yolk sac and AGM tissues from mouse embryos, and we present optimized tissue digestion and antibody conjugation conditions for maximal cell survival prior to identification and retrieval via FACS. Representative FACS analysis plots are shown that identify the hemogenic endothelial cell and HSPC phenotypes, and describe a methylcellulose-based assay for evaluating their blood forming potential on a clonal level.

Hematopoietic stem and progenitor cells (HSPC) derive from specialized (hemogenic) endothelial cells during development, yet little is known about the process by which some endothelial cells specify to become blood forming. We demonstrate a flow-cytometry based method allowing simultaneous isolation of hemogenic endothelial cells and HSPC from murine embryonic tissues.

Isolement des cellules embryonnaires murines Hemogenic endothéliales

The specification of hemogenic endothelial cells from embryonic vascular endothelium occurs during brief developmental periods within distinct tissues, ...

The Production of Pluripotent Stem Cells from Mouse Amniotic Fluid Cells Using a Transposon System

Induced pluripotent stem (iPS) cells are generated from mouse and human somatic cells by forced expression of defined transcription factors using different methods. Here, we produced iPS cells from mouse amniotic fluid cells, using a non-viral-based transposon system. All obtained iPS cell lines exhibited characteristics of pluripotent cells, including the ability to differentiate toward derivatives of all three germ layers in vitro and in vivo. This strategy opens up the possibility of using cells from diseased fetuses to develop new therapies for birth defects.

In this study, we generate induced pluripotent stem cells from mouse amniotic fluid cells, using a non-viral-based transposon system.

La production de cellules souches pluripotentes de souris amniotique Cellules Fluid Utilisation d&#39;un système de transposon

Induced pluripotent stem (iPS) cells are generated from mouse and human somatic cells by forced expression of defined transcription factors using ...

Horizontal Whole Mount: A Novel Processing and Imaging Protocol for Thick, Three-dimensional Tissue Cross-sections of Skin

Processing a tissue of interest to generate a microscopic image that supports a scientific argument can be challenging. The acquisition of high-quality microscopic images is not entirely dependent upon the quality of the microscope, but also upon the methods of tissue processing, which often involve multiple critical actions or steps. Furthermore, mesenchymal cell types in the skin and other tissues represent a new challenge for tissue preparation and imaging. Here, we present a complete process, from tissue harvest to microscopy. Our technique, called &#34;horizontal whole mount,&#34; is one that novices can quickly become proficient in and that allows for antigen preservation and detection in 60-300 &#181;m-thick sections cut with a cryostat. Sections of this thickness provide enhanced visualization of tissue microarchitecture in a three-dimensional environment. In addition, the protocol preserves mesenchymal cells in a manner that enhances image quality when compared to standard cryostat or paraffin sections, thereby increasing the efficacy and reliability of immunostaining. We believe that this protocol will benefit all laboratories that visualize skin, and possibly other tissues and organs.

This work presents a novel processing and imaging protocol for thick, three-dimensional tissue cross-section analysis that enables the full exploitation of confocal imaging modalities. This protocol preserves antigenicity and represents a robust system to analyze skin histology and potentially other tissue types.

Horizontal Whole Mount: un protocole de traitement et d&#39;imagerie géniaux pour les sections transversales épaisses en tissu tridimensionnel

Processing a tissue of interest to generate a microscopic image that supports a scientific argument can be challenging. The acquisition of high-quality ...

Rapid, Directed Differentiation of Retinal Pigment Epithelial Cells from Human Embryonic or Induced Pluripotent Stem Cells

We describe a robust method to direct the differentiation of pluripotent stem cells into retinal pigment epithelial cells (RPE). The purpose of providing a detailed and thorough protocol is to clearly demonstrate each step and to make this readily available to researchers in the field. This protocol results in a homogenous layer of RPE with minimal or no manual dissection needed. The method presented here has been shown to be effective for induced pluripotent stem cells (iPSC) and human embryonic stem cells. Additionally, we describe methods for cryopreservation of intermediate cell banks that allow long-term storage. RPE generated using this protocol might be useful for iPSC disease-in-a-dish modeling or clinical application.

This protocol describes how to produce retinal pigment epithelial cells (RPE) from pluripotent stem cells. The method uses a combination of growth factors and small molecules to direct the differentiation of stem cells into immature RPE in fourteen days and mature, functional RPE after three months.

Rapide, réalisée la différenciation des cellules épithéliales pigmentaire rétinien de cellules souches pluripotentes humaines embryonnaires ou induit

We describe a robust method to direct the differentiation of pluripotent stem cells into retinal pigment epithelial cells (RPE). The purpose of providing ...

Computational Analysis of the Caenorhabditis elegans Germline to Study the Distribution of Nuclei, Proteins, and the Cytoskeleton

The Caenorhabditis elegans (C. elegans) germline is used to study several biologically important processes including stem cell development, apoptosis, and chromosome dynamics. While the germline is an excellent model, the analysis is often two dimensional due to the time and labor required for three-dimensional analysis. Major readouts in such studies are the number/position of nuclei and protein distribution within the germline. Here, we present a method to perform automated analysis of the germline using confocal microscopy and computational approaches to determine the number and position of nuclei in each region of the germline. Our method also analyzes germline protein distribution that enables the three-dimensional examination of protein expression in different genetic backgrounds. Further, our study shows variations in cytoskeletal architecture in distinct regions of the germline that may accommodate specific spatial developmental requirements. Finally, our method enables automated counting of the sperm in the spermatheca of each germline. Taken together, our method enables rapid and reproducible phenotypic analysis of the C. elegans germline.

Computational Analysis of the Caenorhabditis elegans Germline to Study the Distribution of Nuclei, Proteins, and the Cytoskeleton

We present an automated method for three-dimensional reconstruction of the Caenorhabditis elegans germline. Our method determines the number and position of each nucleus within the germline and analyses germline protein distribution and cytoskeletal structure.

Analyse de calcul de la lignée germinale de Caenorhabditis elegans pour étudier la Distribution des noyaux, les protéines et le cytosquelette

The Caenorhabditis elegans (C. elegans) germline is used to study several biologically important processes including stem cell development, apoptosis, and ...

In Vitro Generation of Somite Derivatives from Human Induced Pluripotent Stem Cells

In response to signals such as WNTs, bone morphogenetic proteins (BMPs), and sonic hedgehog (SHH) secreted from surrounding tissues, somites (SMs) give rise to multiple cell types, including the myotome (MYO), sclerotome (SCL), dermatome (D), and syndetome (SYN), which in turn develop into skeletal muscle, axial skeleton, dorsal dermis, and axial tendon/ligament, respectively. Therefore, the generation of SMs and their derivatives from human induced pluripotent stem cells (iPSCs) is critical to obtain pluripotent stem cells (PSCs) for application in regenerative medicine and for disease research in the field of orthopedic surgery. Although the induction protocols for MYO and SCL from PSCs have been previously reported by several researchers, no study has yet demonstrated the induction of SYN and D from iPSCs. Therefore, efficient induction of fully competent SMs remains a major challenge. Here, we recapitulate human SM patterning with human iPSCs in vitro by mimicking the signaling environment during chick/mouse SM development, and report on methods of systematic induction of SM derivatives (MYO, SCL, D, and SYN) from human iPSCs under chemically defined conditions through the presomitic mesoderm (PSM) and SM states. Knowledge regarding chick/mouse&#160;SM development was successfully applied to the induction of SMs with human iPSCs. This method could be a novel tool for studying human somitogenesis and patterning without the use of embryos and for cell-based therapy and disease modeling.

We present here a protocol for the differentiation of human induced pluripotent stem cells into each somite derivative (myotome, sclerotome, dermatome, and syndetome) in chemically defined conditions, which has applications in future disease modeling and cell-based therapies in orthopedic surgery.

Dans Vitro génération du Somite dérivés de Human induit Pluripotent Stem cellules

In response to signals such as WNTs, bone morphogenetic proteins (BMPs), and sonic hedgehog (SHH) secreted from surrounding tissues, somites (SMs) give ...

Hemogenic Endothelium Differentiation from Human Pluripotent Stem Cells in A Feeder- and Xeno-free Defined Condition

Deriving functional hematopoietic stem and progenitor cells (HSPCs) from human pluripotent stem cells (PSCs) have been an elusive goal for autologous transplants to treat hematological and malignant disorders. Hemogenic endothelium (HE) is an amenable platform to produce functional HSPCs by transcription factors or to induce lymphocytes in a robust manner. However, current methods to derive HE are either costly or variable in yield. In this protocol, we established a cost-effective and precise method to derive HE within 4 days in a feeder- and xeno-free defined condition. The resultant HE underwent an endothelial-to-hematopoietic transition and produced CD34+CD45+ clonogenic hematopoietic progenitors. The potential capacity of our platform for generating functional HSPCs will have broad applications in disease modeling and screening for therapeutic compounds.

Here, we present a protocol to precisely form hemogenic endothelium from human pluripotent stem cells in a feeder- and xeno-free condition. This method will have broad applications in disease modeling and screening for therapeutic compounds.

Différenciation hémogénique de l'endothélium par des cellules souches pluripotentes humaines dans une condition définie sans mangeoire et sans xéno

Deriving functional hematopoietic stem and progenitor cells (HSPCs) from human pluripotent stem cells (PSCs) have been an elusive goal for autologous ...