Name: application of aorta-gonad-mesonephros explant culture system in developmental hematopoiesis
Uploaded: 2017-11-03T13:00:00
Description: Watch this Scientific Journal Video about Application of Aorta-gonad-mesonephros Explant Culture System in Developmental Hematopoiesis at JoVE.com

We thank Suwei Gao for help in figure preparation. This work was supported by grants from the National Natural Science Foundation of China (81530004, 31425016) and the Ministry of Science and Technology of China (2016YFA0100500). J.L. performed the experiments and drafted the manuscript; F.L. edited the manuscript. Both authors read and approved the final manuscript.

All the procedures including animal subjects have been approved by the Ethical Review Committee in the Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
1. Material Preparation
<ol>
	<li>Sterilize the 0.65 &#181;m filters with ultraviolet rays produced under the ultraviolet ray lamp on the clean bench for 4 h and turn the filters over after the 2 h mark. 
	NOTE: When working with UV light, wear appropriate protection.</li>
	<li>Sterilize the stainless steel meshes with ...

<ol>
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C., Robin, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+the+founder+of+adult+hematopoiesis+in+the+mouse+embryo+aorta.">Imaging the founder of adult hematopoiesis in the mouse embryo aorta.</a> Cell cycle. 9, 2489-2490 (2010).</li><li>Kissa, K., Herbomel, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blood+stem+cells+emerge+from+aortic+endothelium+by+a+novel+type+of+cell+transition.">Blood stem cells emerge from aortic endothelium by a novel type of cell transition.</a> Nature. 464, 112-115 (2010).</li><li>Zovein, A. 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=Fate+tracing+reveals+the+endothelial+origin+of+hematopoietic+stem+cells.">Fate tracing reveals the endothelial origin of hematopoietic stem cells.</a> Cell Stem Cell. 3, 625-636 (2008).</li><li>Kumaravelu, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+developmental+anatomy+of+definitive+haematopoietic+stem+cells+long-term+repopulating+units+(HSC/RUs):+role+of+the+aorta-gonad-mesonephros+(AGM)+region+and+the+yolk+sac+in+colonisation+of+the+mouse+embryonic+liver.">Quantitative developmental anatomy of definitive haematopoietic stem cells long-term repopulating units (HSC/RUs): role of the aorta-gonad-mesonephros (AGM) region and the yolk sac in colonisation of the mouse embryonic liver.</a> Development. 129, 4891-4899 (2002).</li><li>Orkin, S. 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Q., Liu, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=5-hydroxytryptamine+synthesized+in+the+aorta-gonad-mesonephros+regulates+hematopoietic+stem+and+progenitor+cell+survival.">5-hydroxytryptamine synthesized in the aorta-gonad-mesonephros regulates hematopoietic stem and progenitor cell survival.</a> J Exp Med. 214, 529-545 (2017).</li><li>Souilhol, 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=Inductive+interactions+mediated+by+interplay+of+asymmetric+signalling+underlie+development+of+adult+haematopoietic+stem+cells.">Inductive interactions mediated by interplay of asymmetric signalling underlie development of adult haematopoietic stem cells.</a> Nature communications. 7, 10784 (2016).</li><li>Fitch, S. 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It is well known that mature HSCs in the bone marrow can repopulate the blood system of irradiated recipients. Unlike these functional HSCs, the emerging HSCs in the AGM of mouse embryos are immature. Direct transplantation results showed that type I (VE-cad+ CD45- CD41+) and type II (VE-cad+ CD45+) pre-HSCs possess no reconstitution ability20. Taking advantage of the AGM explant culture system, the nascent HSCs in the AGM region can reconstit...

Hematopoietic stem cells (HSCs) are tissue-specific adult stem cells that possess multilineage potential including erythroid, myeloid, and lymphoid cells as well as the ability to self-renew. Recent studies have shown that the earliest HSCs arose from a specialized endothelial population, known as hemogenic endothelium (HE), through the endothelial to hematopoietic transition (EHT) at the ventral wall of dorsal aorta1,2,3,4. Once formed in the aorta-gonad-mesonephros (AGM) region from embryonic (E) 10.5 to E12.5 in the mouse embryo, HSCs will migrate into the fetal liver for expansion and finally colonize the bone marrow to maintain adult hematopoiesis throughout an individual&#39;s&#160;life5,6. Although this has been studied for many years, the underlying mechanisms of HSC emergence and development remain incompletely understood.
Unlike in vitro fertilization and development of zebrafish embryos, intrauterine development of mouse embryos makes the study of definitive hematopoiesis during embryogenesis much more inconvenient. Although genetic experiments using knockout (KO) mice are commonly utilized, the lack of certain KO mice also limits their use in the hematopoietic research field. In addition, in vivo rescue experiments are not easily performed in KO mice. Since 1996, the AGM explant culture has been developed for hematopoietic studies by the pioneers in the field7. With the help of this culture system, ventral tissues of the AGM region have been identified to promote HSC activity, while dorsal tissues exert an opposite effect8,9. The AGM explant culture system has also been applied to determine the roles of Serotonin, Mpl, SCF, BMP, and Hedgehog signaling in HSC development10,11,12,13,14. Importantly, it is also a popular method used to rescue hematopoietic defects in mutant embryos13,15.

<table style="border-collapse:collapse;width:458pt" width="610">
	<colgroup>
		<col style="width:162pt" width="216" />
		<col style="width:81pt" width="108" />
		<col style="width:89pt" width="119" />
		<col style="width:125pt" width="167" />
	</colgroup>
	<tbody>
		<tr height="21" style="height:15.75pt">
			<td class="xl67" height="21" style="width:162pt;height:15.75pt" width="216">durapore 0.65 &#181;m filters</td>
			<td class="xl68" style="width:81pt" width="108">Millipore</td>
			<td class="xl69" style="width:89pt" width="119">R5BA63787</td>
			<td class="xl67" style="width:125pt" width="167">AGM explant culture</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl67" height="42" style="height:31.5pt">M5300 long-term culture medium</td>
			<td class="xl68" style="width:81pt" width="108">Stem Cell Technologies</td>
			<td class="xl69" style="width:89pt" width="119">5300</td>
			<td class="xl67">AGM explant culture</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl68" height="21" style="width:162pt;height:15.75pt" width="216">Trizol&#160;</td>
			<td class="xl68" style="width:81pt" width="108">Tiangen</td>
			<td class="xl69" style="width:89pt" width="119">5829</td>
			<td class="xl67">RNA extration</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl68" height="21" style="width:162pt;height:15.75pt" width="216">M-MLV reverse transcriptase</td>
			<td class="xl68" style="width:81pt" width="108">Promega</td>
			<td class="xl69" style="width:89pt" width="119">90694</td>
			<td class="xl67">reverse transcription</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl68" height="21" style="width:162pt;height:15.75pt" width="216">SYBR Green</td>
			<td class="xl68" style="width:81pt" width="108">Qiagen</td>
			<td class="xl69" style="width:89pt" width="119">A6002</td>
			<td class="xl67">quantatitive real-time PCR</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl68" height="21" style="width:162pt;height:15.75pt" width="216">protease inhibitor</td>
			<td class="xl68" style="width:81pt" width="108">Roche</td>
			<td class="xl69" style="width:89pt" width="119">55622</td>
			<td class="xl67">Protein extration</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl68" height="21" style="width:162pt;height:15.75pt" width="216">collagenase</td>
			<td class="xl68" style="width:81pt" width="108">Sigma</td>
			<td class="xl69" style="width:89pt" width="119">C2674</td>
			<td class="xl67">digestion of AGM tissues</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl68" height="42" style="width:162pt;height:31.5pt" width="216">MethoCult GF M3434 medium</td>
			<td class="xl68" style="width:81pt" width="108">Stem Cell Technologies</td>
			<td class="xl69" style="width:89pt" width="119">3434</td>
			<td class="xl67">CFU-C assay</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl68" height="42" style="width:162pt;height:31.5pt" width="216">ultra-low attachment 24-well plates</td>
			<td class="xl68" style="width:81pt" width="108">Costar</td>
			<td class="xl69" style="width:89pt" width="119">3473</td>
			<td class="xl67">CFU-C assay</td>
		</tr>
		<tr height="63" style="height:47.25pt">
			<td class="xl67" height="63" style="height:47.25pt">C57BL/6 CD45.2 mice</td>
			<td class="xl68" style="width:81pt" width="108">Beijing HFK Bioscience Co. Ltd</td>
			<td class="xl68" style="width:89pt" width="119"></td>
			<td class="xl67">CFU-S assay</td>
		</tr>
		<tr height="63" style="height:47.25pt">
			<td class="xl68" height="63" style="width:162pt;height:47.25pt" width="216">C57BL/6 CD45.1 mice</td>
			<td class="xl68" style="width:81pt" width="108">Beijing HFK Bioscience Co. Ltd</td>
			<td class="xl68" style="width:89pt" width="119"></td>
			<td class="xl67">Long-term transplantation</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl68" height="42" style="width:162pt;height:31.5pt" width="216">phosphate buffered saline</td>
			<td class="xl68" style="width:81pt" width="108">Life Technologines</td>
			<td class="xl69" style="width:89pt" width="119">8115284</td>
			<td class="xl68" style="width:125pt" width="167">AGM Collection</td>
		</tr>
		<tr height="21" style="height:15.75pt">
			<td class="xl68" height="21" style="width:162pt;height:15.75pt" width="216">Penicillin-Streptomycin solution</td>
			<td class="xl68" style="width:81pt" width="108">HyClone</td>
			<td class="xl68" style="width:89pt" width="119">SV30010</td>
			<td class="xl68" style="width:125pt" width="167">AGM explant culture</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl68" height="42" style="width:162pt;height:31.5pt" width="216">anti-CD45.2-PE-CY7</td>
			<td class="xl68" style="width:81pt" width="108">eBioscience</td>
			<td class="xl68" style="width:89pt" width="119">25-0454-80</td>
			<td class="xl68" style="width:125pt" width="167">Long-term transplantation</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl68" height="42" style="width:162pt;height:31.5pt" width="216">anti-CD45-FITC</td>
			<td class="xl68" style="width:81pt" width="108">eBioscience</td>
			<td class="xl68" style="width:89pt" width="119">11-0451-81</td>
			<td class="xl68" style="width:125pt" width="167">Long-term transplantation</td>
		</tr>
		<tr height="105" style="height:78.75pt">
			<td class="xl68" height="105" style="width:162pt;height:78.75pt" width="216">UV lamp</td>
			<td class="xl68" style="width:81pt" width="108">Beijing jiangmorning yuan bio-technology co., LTD</td>
			<td class="xl68" style="width:89pt" width="119">039-14402</td>
			<td class="xl68" style="width:125pt" width="167">power: 30W</td>
		</tr>
		<tr height="63" style="height:47.25pt">
			<td class="xl68" height="63" style="width:162pt;height:47.25pt" width="216">stainless steel mesh</td>
			<td class="xl68" style="width:81pt" width="108">AS ONE SHANGHAI Corporation</td>
			<td class="xl68" style="width:89pt" width="119">2-9817-10&#160;</td>
			<td class="xl68" style="width:125pt" width="167">aperture diameter: 2.5 mm</td>
		</tr>
		<tr height="42" style="height:31.5pt">
			<td class="xl68" height="42" style="width:162pt;height:31.5pt" width="216">hydrocortisone</td>
			<td class="xl68" style="width:81pt" width="108">Sigma</td>
			<td class="xl68" style="width:89pt" width="119">H0396</td>
			<td class="xl68" style="width:125pt" width="167">selectively diluted into M5300 medium</td>
		</tr>
	</tbody>
</table>

application of aorta-gonad-mesonephros explant culture system in developmental hematopoiesis

The limitation of using mouse embryos for hematopoiesis studies is the added inconvenience in operations, which is largely due to the intrauterine development of the embryo. Although genetic data from knockout (KO) mice are convincing, it is not realistic to generate KO mice for all genes as needed. In addition, performing in vivo rescue experiments to consolidate the data obtained from KO mice is not convenient. To overcome these limitations, the Aorta-Gonad-Mesonephros (AGM) explant culture was developed as an appropriate system to study hematopoietic stem cell (HSC) development. Especially for rescue experiments, it can be used to recover the impaired hematopoiesis in KO mice. By adding the appropriate chemicals into the medium, the impaired signaling can be reactivated or up-regulated pathways can be inhibited. With the use of this method, many experiments can be performed to identify the critical regulators of HSC development, including HSC related gene expression at mRNA and protein levels, colony formation ability, and reconstitution capacity. This series of experiments would be helpful in defining the underlying mechanisms essential for HSC development in mammals.

A recent publication reported endothelial cell-derived serotonin promotes the survival of HSCs by inhibiting the pro-apoptotic pathway in the AGM13. To confirm the promoting effect of serotonin on HSC development, Fluoxetine was included. As a selective serotonin re-uptake inhibitor (SSRI), Fluoxetine has been demonstrated to inhibit serotonin re-absorption in peripheral tissues16,17,<sup class="...

Watch this Scientific Journal Video about Application of Aorta-gonad-mesonephros Explant Culture System in Developmental Hematopoiesis at JoVE.com

Application of Aorta-gonad-mesonephros Explant Culture System in Developmental Hematopoiesis

This protocol describes using cultured Aorta-Gonad-Mesonephros for expression analyses, colony-forming units in the culture and spleen, and long-term reconstitution to determine the effect of regulatory factors and signaling pathways on hematopoietic stem cell development. This has been demonstrated as an effective system for studying hematopoietic stem cell biology and function.

The limitation of using mouse embryos for hematopoiesis studies is the added inconvenience in operations, which is largely due to the intrauterine ...

The overall goal of this experiment is to use an aorta-gonad-mesonephros explant culture to investigate the critical regulators of hematopoietic stem cell development. This method can help answer key questions in HSC biology and function fields about how to identify the factors involved in the regulation of HSC development in mammals. The main advantage of this technique is that these regulators can be verified through DNA expression analysis and the colony formation ability and the reconstitution capacity of the HSC.Generally individuals new to this method will struggle because the precise separation of AGM from the surrounding tissues in the trunk region requires practice to master. Before beginning the procedure place stainless steel meshes into individual wells of a six-well plate containing two milliliters of freshly prepared fluoxetine-supplemented medium per well. Place one UV-sterilized 0.65 microliter filter per experimental well into a glass cell culture dish containing fresh boiling water for two three-minute washes, immersing the filters in a container of room temperature PBS for two minutes after each wash.Then place one filter onto each steel mesh at the air-liquid interface of each well. Next use the dissecting scissors to strip the uterus from an embryonic day-11 pregnant mouse and harvest the embryos from the uterus. Using dissecting scissors remove the yolk sac, umbilical cord and viscera from the embryo body.And carefully remove the dorsal nerve tissues and surrounding muscular tissues. Using forceps remove the tissues from the anterior and hind limbs. And separate the AGM region from the embryo body.Then place each AGM onto a single filter at the air-liquid interface of each well. Place the cultures in a 37 degree Celsius and 5%CO2 incubator. After two to three days, transfer the AGM samples into individual 1.5-milliliter microcentrifuge tubes containing 200 microliters of collagenase for their dissociation at 37 degrees Celsius for about 20 minutes with shaking every five minutes.At the end of the digestion stop the reactions with 200 microlilters of serum per explant. Transfer the entire contents of each tube into individual wells of a 24-well ultra-low attachment plate containing 500 to 600 microliters of M3434 medium per well. Mix the cells in each well with a one milliliter syringe without a needle.Place the plate in the cell culture incubator. The number of colony-forming units within each well can then be scored after seven to 10 days of culture. For in vivo AGM explant transplantation after two to three days of AGM culture as just demonstrated, lethally eradiate eight to 10-week-old male C57 black six mice with nine grays of radiation.Four to five hours later dissociate the harvested explants in 200 microliters of collagenase per samples as demonstrated. Load of 0.5 to one embryo equivalent of the resulting single-cell suspensions into one one-milliliter syringe per recipient animal. Place the first irradiated mouse into a restrainer and wipe the tail with a 75%ethanol-soaked cotton swab to promote tail vein vasodilation.Intravenously inject the entire contents of one syringe into a dilated tail vein. Use an antiseptic swab to stop the bleeding after removal of the needle. Then return the animal to its cage, and inject the next animal.11 days after the adoptive transfer the spleens can be fixed in Bouin's solution for macroscopic enumeration of the visible spleen colonies. Fluoxetine-supplemented AGM cultures demonstrate an increased expression of Runx1, a pivotal gene for HSC development at the mRNA and protein expression levels. Fluoxetine can also significantly increase the colony formation ability of HSC in the AGM including burst-forming unit erythroids, colony-forming unit granular monocytes and colony-forming unit granulocytes, erythrocytes, macrophages and megakaryocytes.Further in vivo transplantation of fluoxetine-treated HSC isolated from AGM explants results in increased numbers of colonies in the spleens of irradiated adult recipient animals. After watching this video, you should have a good understanding of how to isolate the AGM and to perform an AGM explant culture for the identification of the critical regulators of HSC development within the AGM.

application-aorta-gonad-mesonephros-explant-culture-system

Research

JoVE Journal

Developmental Biology

An Optogenetic Approach for Assessing Formation of Neuronal Connections in a Co-culture System

Here we describe a protocol to generate a co-culture consisting of 2 different neuronal populations. Induced pluripotent stem cells (iPSCs) are reprogrammed from human fibroblasts using episomal vectors. Colonies of iPSCs can be observed 30 days after initiation of fibroblast reprogramming. Pluripotent colonies are manually picked and grown in neural induction medium to permit differentiation into neural progenitor cells (NPCs). iPSCs rapidly convert into neuroepithelial cells within 1 week and retain the capability to self-renew when maintained at a high culture density. Primary mouse NPCs are differentiated into astrocytes by exposure to a serum-containing medium for 7 days and form a monolayer upon which embryonic day 18 (E18) rat cortical neurons (transfected with channelrhodopsin-2 (ChR2)) are added. Human NPCs tagged with the fluorescent protein, tandem dimer Tomato (tdTomato), are then seeded onto the astrocyte/cortical neuron culture the following day and allowed to differentiate for 28 to 35 days. We demonstrate that this system forms synaptic connections between iPSC-derived neurons and cortical neurons, evident from an increase in the frequency of synaptic currents upon photostimulation of the cortical neurons. This co-culture system provides a novel platform for evaluating the ability of iPSC-derived neurons to create synaptic connections with other neuronal populations.

A protocol to generate a co-culture system consisting of neurons derived from induced pluripotent stem cells (iPSCs), primary cortical neurons and astrocytes is described. This co-culture system allows detection of the formation of synaptic contacts and circuits between new, iPSC-derived neurons and pre-existing cortical neurons expressing channelrhodopsin-2.

Here we describe a protocol to generate a co-culture consisting of 2 different neuronal populations. Induced pluripotent stem cells (iPSCs) are ...

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

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

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

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

Application of RNAi and Heat-shock-induced Transcription Factor Expression to Reprogram Germ Cells to Neurons in C. elegans

Studying the cell biological processes during converting the identities of specific cell types provides important insights into mechanism that maintain and protect cellular identities. The conversion of germ cells into specific neurons in the nematode Caenorhabditis elegans (C. elegans) is a powerful tool for performing genetic screens in order to dissect regulatory pathways that safeguard established cell identities. Reprogramming of germ cells to a specific type of neurons termed ASE requires transgenic animals that allow broad over-expression of the Zn-finger transcription factor (TF) CHE-1. Endogenous CHE-1 is expressed exclusively in two head neurons and is required to specify the glutamatergic ASE neurons fate, which can easily be visualized by the gcy-5prom::gfp reporter. A trans gene containing the heat-shock promoter-driven che-1 gene expression construct allows broad mis-expression of CHE-1 in the entire animal upon heat-shock treatment. The combination of RNAi against the chromatin-regulating factor LIN-53 and heat-shock-induced che-1 over-expression leads to reprogramming of germ cell into ASE neuron-like cells. We describe here the specific RNAi procedure and appropriate conditions for heat-shock treatment of transgenic animals in order to successfully induce germ cell to neuron conversion.

Application of RNAi and Heat-shock-induced Transcription Factor Expression to Reprogram Germ Cells to Neurons in C. elegans

This protocol describes how to study cellular processes during cell fate conversion in Caenorhabditis elegans in vivo. Using transgenic animals, allowing heat-shock promoter-driven overexpression of the neuron fate-inducing transcription factor CHE-1 and RNAi-mediated depletion of the chromatin-regulating factor LIN-53 germ cell to neuron reprogramming can be observed in vivo.

Studying the cell biological processes during converting the identities of specific cell types provides important insights into mechanism that maintain ...

Efficient Generation of Pancreas/Duodenum Homeobox Protein 1+ Posterior Foregut/Pancreatic Progenitors from hPSCs in Adhesion Cultures

Human pluripotent stem cell (hPSC)-derived pancreatic cells are a promising cell source for regenerative medicine and a platform to study human developmental processes. Stepwise directed differentiation that recapitulates developmental processes is one of the major ways to generate pancreatic cells including pancreas/duodenum homeobox protein 1+ (PDX1+) pancreatic progenitor cells. Conventional protocols initiate the differentiation with small colonies shortly after the passage. However, in the state of colonies or aggregates, cells are prone to heterogeneities, which might hamper the differentiation to PDX1+ cells. Here, we present a detailed protocol to differentiate hPSCs into PDX1+ cells. The protocol consists of four steps and initiates the differentiation by seeding dissociated single cells. The induction of SOX17+ definitive endoderm cells was followed by the expression of two primitive gut tube markers, HNF1&#946; and HNF4&#945;, and eventual differentiation into PDX1+ cells. The present protocol provides easy handling and may improve and stabilize the differentiation efficiency of some hPSC lines that were previously found to differentiate inefficiently into endodermal lineages or PDX1+ cells.

Efficient Generation of Pancreas/Duodenum Homeobox Protein 1+ Posterior Foregut/Pancreatic Progenitors from hPSCs in Adhesion Cultures

Here, we present a detailed protocol to differentiate human pluripotent stem cells (hPSCs) into pancreas/duodenum homeobox protein 1+ (PDX1+) cells for the generation of pancreatic lineages based on the non-colony type monolayer growth of dissociated single cells. This method is suitable for producing homogenous hPSC-derived cells, genetic manipulation and screening.

Human pluripotent stem cell (hPSC)-derived pancreatic cells are a promising cell source for regenerative medicine and a platform to study human ...

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.

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.

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

In vitro Neuromuscular Junction Induced from Human Induced Pluripotent Stem Cells

The neuromuscular junction (NMJ) is a specialized synapse that transmits action potentials from the motor neuron to skeletal muscle for mechanical movement. The architecture of the NMJ structure influences the functions of the neuron, the muscle and the mutual interaction. Previous studies have reported many strategies by co-culturing the motor neurons and myotubes to generate NMJ in vitro with complex induction process and long culture period but have struggled to recapitulate mature NMJ morphology and function. Our in vitro NMJ induction system is constructed by differentiating human iPSC in a single culture dish. By switching the myogenic and neurogenic induction medium for induction, the resulting NMJ contained pre- and post- synaptic components, including motor neurons, skeletal muscle and Schwann cells in the one month culture. The functional assay of NMJ also showed that the myotubes contraction can be triggered by Ca++ then inhibited by curare, an acetylcholine receptor (AChR) inhibitor, in which the stimulating signal is transmitted through NMJ. This simple and robust approach successfully derived the complex structure of NMJ with functional connectivity. This in vitro human NMJ, with its integrated structures and function, has promising potential for studying pathological mechanisms and compound screening.

Here we provide a protocol to generate in vitro NMJs from human induced pluripotent stem cells (iPSCs). This method can induce NMJs with mature morphology and function in 1 month in a single well. The resulting NMJs could potentially be used to model related diseases, to study pathological mechanisms or to screen drug compounds for therapy.

The neuromuscular junction (NMJ) is a specialized synapse that transmits action potentials from the motor neuron to skeletal muscle for mechanical ...

A 3-D Tail Explant Culture to Study Vertebrate Segmentation in Zebrafish

Vertebrate embryos pattern their major body axis as repetitive somites, the precursors of vertebrae, muscle, and skin. Somites progressively segment from the presomitic mesoderm (PSM) as the tail end of the embryo elongates posteriorly. Somites form with regular periodicity and scale in size. Zebrafish is a popular model organism as it is genetically tractable and has transparent embryos that allow for live imaging. Nevertheless, during somitogenesis, fish embryos are wrapped around a large, rounding yolk. This geometry limits live imaging of PSM tissue in zebrafish embryos, particularly at higher resolutions that require a close objective working distance. Here, we present a flattened 3-D tissue culture method for live imaging of zebrafish tail explants. Tail explants mimic intact embryos by displaying a proportional slowdown of axis elongation and shortening of rostrocaudal somite lengths. We are further able to stall axis elongation speed through explant culture. This, for the first time, enables us to untangle the chemical input of signaling gradients from the mechanistic input of axial elongation. In future studies, this method can be combined with a microfluidic setup to allow time-controlled pharmaceutical perturbations or screening of vertebrate segmentation without any drug penetration concerns.

Here, we present the protocol for 3-D tissue culture of the zebrafish posterior body axis, enabling live study of vertebrate segmentation. This explant model provides control over axis elongation, alteration of morphogen sources, and subcellular resolution tissue-level live imaging.

Vertebrate embryos pattern their major body axis as repetitive somites, the precursors of vertebrae, muscle, and skin. Somites progressively segment from ...

Use of Trowell-Type Organ Culture to Study Regulation of Dental Stem Cells

Organ development, function, and regeneration depend on stem cells, which reside within discrete anatomical spaces called stem cell niches. The continuously growing mouse incisor provides an excellent model to study tissue-specific stem cells. The epithelial tissue-specific stem cells of the incisor are located at the proximal end of the tooth in a niche called the cervical loop. They provide a continuous influx of cells to counterbalance the constant abrasion of the self-sharpening tip of the tooth. Presented here is a detailed protocol for the isolation and culture of the proximal end of the mouse incisor that houses stem cells and their niche. This is a modified Trowell-type organ culture protocol that enables in vitro culture of tissue pieces (explants), as well as the thick tissue slices at the liquid/air interface on a filter supported by a metal grid. The organ culture protocol described here enables tissue manipulations not feasible in vivo, and when combined with the use of a fluorescent reporter(s), it provides a platform for the identification and tracking of discrete cell populations in live tissues over time, including stem cells. Various regulatory molecules and pharmacological compounds can be tested in this system for their effect on stem cells and their niches. This ultimately provides a valuable tool to study stem cell regulation and maintenance.

The Trowell-type organ culture method has been used to unravel complex signaling networks that govern tooth development and, more recently, for studying regulation involved in stem cells of the continuously growing mouse incisor. Fluorescent-reporter animal models and live-imaging methods facilitate in-depth analyses of dental stem cells and their specific niche microenvironment.

Organ development, function, and regeneration depend on stem cells, which reside within discrete anatomical spaces called stem cell niches. The ...

An Explant System for Time-Lapse Imaging Studies of Olfactory Circuit Assembly in Drosophila

~Neurons are precisely interconnected to form circuits essential for the proper function of the brain. The Drosophila olfactory system provides an excellent model to investigate this process since 50 types of olfactory receptor neurons (ORNs) from the antennae and maxillary palps project their axons to 50 identifiable glomeruli in the antennal lobe and form synaptic connections with dendrites from 50 types of second-order projection neurons (PNs). Previous studies mainly focused on identifying important molecules that regulate the precise targeting in the olfactory circuit using fixed tissues. Here, an antennae-brain explant system that recapitulates key developmental milestones of olfactory circuit assembly in culture is described. Through dissecting the external cuticle and cleaning opaque fat bodies covering the developing pupal brain, high quality images of single neurons from live brains can be collected using two-photon microscopy. This allows time-lapse imaging of single ORN axon targeting from live tissue. This approach will help reveal important cell biological contexts and functions of previously identified important genes and identify mechanisms underpinning the dynamic process of circuit assembly.

An Explant System for Time-Lapse Imaging Studies of Olfactory Circuit Assembly in Drosophila

This protocol describes the dissection procedure, culture condition, and live imaging of an antennae-brain explant system for the study of the olfactory circuit assembly.