We thank the National Center for Protein Sciences, Beijing (Peking University) and the Peking-Tsinghua Center for the Life Science Computing Platform. This work was supported by the Ministry of Science and Technology of China (2015CB942800), the National Natural Science Foundation of China (31521004, 31471358, and 31522036), and funding from Peking-Tsinghua Center for Life Sciences to C.-R.X.

<ol>
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R., 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+adult+mouse+and+human+pancreas+contain+rare+multipotent+stem+cells+that+express+insulin.">The adult mouse and human pancreas contain rare multipotent stem cells that express insulin.</a> Cell Stem Cell. 8 (3), 281-293 (2011).</li><li>Dorrell, 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=Human+islets+contain+four+distinct+subtypes+of+beta+cells.">Human islets contain four distinct subtypes of beta cells.</a> Nature Communications. 7, 11756 (2016).</li><li>Bader, 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=Identification+of+proliferative+and+mature+beta-cells+in+the+islets+of+Langerhans.">Identification of proliferative and mature beta-cells in the islets of Langerhans.</a> Nature. 535 (7612), 430-434 (2016).</li><li>Saliba, A. 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The authors have nothing to disclose.

In this protocol, we demonstrated an effective and easy-to-use method for studying the single-cell expression profiles of pancreatic &#946; cells. This method could be used to isolate endocrine cells from embryonic, neonatal and postnatal pancreases and to perform single-cell transcriptomic analyses.
The most critical step is the isolation of single &#946; cells in good condition. Fully perfused pancreases respond better to subsequent digestion. Insufficient perfusion, which usually occurs in ...

The pancreas is a vital metabolic organ in mammals. The pancreas is comprised of endocrine and exocrine compartments. Pancreatic endocrine cells, including insulin-producing &#946; cells and glucagon-producing &#945; cells, cluster together in the islets of Langerhans and coordinately regulate systemic glucose homeostasis. Dysfunction of the endocrine cells results in diabetes mellitus, which has become a major public health issue worldwide.
Pancreatic endocrine cells are derived from Ngn3+ progenitors during embryogenesis1. Later, during the perinatal period, the endocrine cells proliferate to form immature islets. These immature cells continue to develop and gradually become mature islets, which become richly vascularized to regulate blood glucose homeostasis in adults2.
Although a group of transcriptional factors has been identified that regulate &#946; cell differentiation, the precise maturation pathway of &#946; cells is still unclear. Moreover, the &#946; cell maturation process also involves the regulation of cell number expansion3,4 and the generation of cellular heterogeneity5,6. However, the regulatory mechanisms of these processes have not been well studied.
Single-cell RNA-sequencing is a powerful approach that can profile cell subpopulations and trace cell lineage developmental pathways7. Taking advantage of this technology, the key events that occur during pancreatic islet development can be deciphered at the single-cell level8. Among the single-cell RNA-sequencing protocols, Smart-seq2 allows the generation of full-length cDNA with improved sensitivity and accuracy, and the use of standard reagents at lower cost9. Smart-seq2 takes approximately two days to construct a cDNA library for sequencing10.
Here, we propose a method for the isolation of fluorescence-labeled &#946; cells from the pancreases of fetal to adult Ins1-RFP transgenic mice11, using fluorescence-activated cell sorting (FACS), and the performance of transcriptomic analyses at the single-cell level, using Smart-seq2 technology (Figure 1).This protocol can be extended to analyze the transcriptomes of all pancreatic endocrine cell types in normal, pathological and aging states.

<table>
	<tbody>
		<tr>
			<td>Collagenase P</td>
			<td>Roche</td>
			<td>11213873001</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin-EDTA (0.25 %), phenol red</td>
			<td>Thermo Fisher Scientific</td>
			<td>25200114</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum (FBS)</td>
			<td>Hyclone</td>
			<td>SH30071.03</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont #4 Forceps</td>
			<td>Roboz</td>
			<td>RS-4904</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont #5 Forceps</td>
			<td>Roboz</td>
			<td>RS-5058</td>
			<td></td>
		</tr>
		<tr>
			<td>30 G BD Needle 1/2&#34; Length</td>
			<td>BD</td>
			<td>305106</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereo Microscope</td>
			<td>Zeiss</td>
			<td>Stemi DV4</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereo Fluorescence microscope</td>
			<td>Zeiss</td>
			<td>Stereo Lumar V12</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Eppendorf</td>
			<td>5810R</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Eppendorf</td>
			<td>5424R</td>
			<td></td>
		</tr>
		<tr>
			<td>Polystyrene Round-Bottom Tube with Cell-Strainer Cap</td>
			<td>BD-Falcon</td>
			<td>352235</td>
			<td></td>
		</tr>
		<tr>
			<td>96-Well PCR Microplate</td>
			<td>Axygen</td>
			<td>PCR-96-C</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicone Sealing Mat</td>
			<td>Axygen</td>
			<td>AM-96-PCR-RD</td>
			<td></td>
		</tr>
		<tr>
			<td>Thin Well PCR Tube</td>
			<td>Extragene</td>
			<td>P-02X8-CF</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell sorter</td>
			<td>BD Biosciences</td>
			<td>BD FACSAria</td>
			<td></td>
		</tr>
		<tr>
			<td>Capillary pipette</td>
			<td>Sutter</td>
			<td>B100-58-10</td>
			<td></td>
		</tr>
		<tr>
			<td>RNaseZap</td>
			<td>Ambion</td>
			<td>AM9780</td>
			<td></td>
		</tr>
		<tr>
			<td>ERCC RNA Spike-In Mix</td>
			<td>Life Technologies</td>
			<td>4456740</td>
			<td></td>
		</tr>
		<tr>
			<td>Distilled water</td>
			<td>Gibco</td>
			<td>10977</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma-Aldrich</td>
			<td>T9284</td>
			<td></td>
		</tr>
		<tr>
			<td>dNTP mix</td>
			<td>New England Biolabs</td>
			<td>N0447</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant RNase Inhibitor</td>
			<td>Takara</td>
			<td>2313</td>
			<td></td>
		</tr>
		<tr>
			<td>Superscript II reverse transcriptase</td>
			<td>Invitrogen</td>
			<td>18064-014</td>
			<td></td>
		</tr>
		<tr>
			<td>First-strand buffer (5x)</td>
			<td>Invitrogen</td>
			<td>18064-014</td>
			<td></td>
		</tr>
		<tr>
			<td>DTT</td>
			<td>Invitrogen</td>
			<td>18064-014</td>
			<td></td>
		</tr>
		<tr>
			<td>Betaine</td>
			<td>Sigma-Aldrich</td>
			<td>107-43-7</td>
			<td></td>
		</tr>
		<tr>
			<td>MgCl2</td>
			<td>Sigma-Aldrich</td>
			<td>7786-30-3</td>
			<td></td>
		</tr>
		<tr>
			<td>Nuclease-free water</td>
			<td>Invitrogen</td>
			<td>AM9932</td>
			<td></td>
		</tr>
		<tr>
			<td>KAPA HiFi HotStart ReadyMix (2x)</td>
			<td>KAPA Biosystems</td>
			<td>KK2601</td>
			<td></td>
		</tr>
		<tr>
			<td>VAHTS DNA Clean Beads XP beads</td>
			<td>Vazyme</td>
			<td>N411-03</td>
			<td></td>
		</tr>
		<tr>
			<td>Qubit dsDNA HS Assay Kit</td>
			<td>Invitrogen</td>
			<td>Q32854</td>
			<td></td>
		</tr>
		<tr>
			<td>AceQ qPCR SYBR Green Master Mix</td>
			<td>Vazyme</td>
			<td>Q121-02</td>
			<td></td>
		</tr>
		<tr>
			<td>TruePrep DNA Library Prep Kit V2 for Illumina</td>
			<td>Vazyme</td>
			<td>TD502</td>
			<td>Include 5x TTBL, 5x TTE, 5x TS, 5x TAB, TAE</td>
		</tr>
		<tr>
			<td>TruePrep Index Kit V3 for Illumina</td>
			<td>Vazyme</td>
			<td>TD203</td>
			<td>Include 16 N6XX and 24 N8XX</td>
		</tr>
		<tr>
			<td>High Sensitivity NGS Fragment Analysis Kit</td>
			<td>Advanced Analytical Technologies</td>
			<td>DNF-474</td>
			<td></td>
		</tr>
		<tr>
			<td>1x HBSS without Ca2+ and Mg2+</td>
			<td></td>
			<td></td>
			<td>138 mM NaCl; 5.34 mM KCl 
			4.17 mM NaHCO3; 0.34 mM Na2HPO4 
			0.44 mM KH2PO4</td>
		</tr>
		<tr>
			<td>Isolation buffer</td>
			<td></td>
			<td></td>
			<td>1 &#215; HBSS containing 10 mM HEPES, 1 mM MgCl2, 5 mM Glucose, pH 7.4</td>
		</tr>
		<tr>
			<td>FACS buffer</td>
			<td></td>
			<td></td>
			<td>1 &#215; HBSS containing 15 mM HEPES, 5.6 mM Glucose, 1% FBS, pH 7.4</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Sigma-Aldrich</td>
			<td>S5886</td>
			<td></td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sigma-Aldrich</td>
			<td>P9541</td>
			<td></td>
		</tr>
		<tr>
			<td>NaHCO3</td>
			<td>Sigma-Aldrich</td>
			<td>S6297</td>
			<td></td>
		</tr>
		<tr>
			<td>Na2HPO4</td>
			<td>Sigma-Aldrich</td>
			<td>S5136</td>
			<td></td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Sigma-Aldrich</td>
			<td>P5655</td>
			<td></td>
		</tr>
		<tr>
			<td>D-(+)-Glucose</td>
			<td>Sigma-Aldrich</td>
			<td>G5767</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Sigma-Aldrich</td>
			<td>H4034</td>
			<td></td>
		</tr>
		<tr>
			<td>MgCl2</td>
			<td>Sigma-Aldrich</td>
			<td>M2393</td>
			<td></td>
		</tr>
		<tr>
			<td>Oligo-dT30VN primer</td>
			<td>5&#39;-AAGCAGTGGTATCAACGCAGAGTACT30VN-3&#39;</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>TSO</td>
			<td>5&#39;-AAGCAGTGGTATCAACGCAGAGTACATrGrG+G-3&#39;</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ISPCR primers</td>
			<td>5&#39;-AAGCAGTGGTATCAACGCAGAGT-3&#39;</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gapdh Forward primer</td>
			<td>5&#39;-ATGGTGAAGGTCGGTGTGAAC-3&#39;</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gapdh Reverse primer</td>
			<td>5&#39;-GCCTTGACTGTGCCGTTGAAT-3&#39;</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ins2 Forward primer</td>
			<td>5&#39;-TGGCTTCTTCTACACACCCA-3&#39;</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ins2 Reverse primer</td>
			<td>5&#39;-TCTAGTTGCAGTAGTTCTCCA-3&#39;</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

single-cell transcriptomic analyses of mouse pancreatic endocrine cells

Pancreatic endocrine cells, which are clustered in islets, regulate blood glucose stability and energy metabolism. The distinct cell types in islets, including insulin-secreting &#946; cells, are differentiated from common endocrine progenitors during the embryonic stage. Immature endocrine cells expand via cell proliferation and mature during a long postnatal developmental period. However, the mechanisms underlying these processes are not clearly defined. Single-cell RNA-sequencing is a promising approach for the characterization of distinct cell populations and tracing cell lineage differentiation pathways. Here, we describe a method for the single-cell RNA-sequencing of isolated pancreatic &#946; cells from embryonic, neonatal and postnatal pancreases.

Pancreases were dissected from embryonic, neonatal and postnatal mice (Figure 2A and 2B). For mice older than postnatal day 18, the digestive effect depends on the degree of perfusion; therefore, the injection is the most important step for islet isolation (Figure 2C-2E and Table 6). As much collagenase was injected as was possible to fill the pancreas during thi...

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Single-cell Transcriptomic Analyses of Mouse Pancreatic Endocrine Cells

We describe a method for the isolation of endocrine cells from embryonic, neonatal and postnatal pancreases followed by single-cell RNA sequencing. This method allows analyses of pancreatic endocrine lineage development, cell heterogeneity and transcriptomic dynamics.

Pancreatic endocrine cells, which are clustered in islets, regulate blood glucose stability and energy metabolism. The distinct cell types in islets, ...

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Developmental Biology

10.9K Views.  Peking University. We describe a method for the isolation of endocrine cells from embryonic, neonatal and postnatal pancreases followed by single-cell RNA sequencing. This method allows analyses of pancreatic endocrine lineage development, cell heterogeneity and transcriptomic dynamics.

Video: Single-cell Transcriptomic Analyses of Mouse Pancreatic Endocrine Cells

Efficient Differentiation of Pluripotent Stem Cells to NKX6-1+ Pancreatic Progenitors

Pluripotent stem cells have the ability to self renew and differentiate to multiple lineages, making them an attractive source for the generation of pancreatic progenitor cells that can be used for the study of and future treatment of diabetes. This article outlines a four-stage differentiation protocol designed to generate pancreatic progenitor cells from human embryonic stem cells (hESCs). This protocol can be applied to a number of human pluripotent stem cell (hPSC) lines. The approach taken to generate pancreatic progenitor cells is to differentiate hESCs to accurately model key stages of pancreatic development. This begins with the induction of the definitive endoderm, which is achieved by culturing the cells in the presence of Activin A, basic Fibroblast Growth Factor (bFGF) and CHIR990210. Further differentiation and patterning with Fibroblast Growth Factor 10 (FGF10) and Dorsomorphin generates cells resembling the posterior foregut. The addition of Retinoic Acid, NOGGIN, SANT-1 and FGF10 differentiates posterior foregut cells into cells characteristic of pancreatic endoderm. Finally, the combination of Epidermal Growth Factor (EGF), Nicotinamide and NOGGIN leads to the efficient generation of PDX1+/NKX6-1+ cells. Flow cytometry is performed to confirm the expression of specific markers at key stages of pancreatic development. The PDX1+/NKX6-1+ pancreatic progenitors at the end of stage 4 are capable of generating mature &#946; cells upon transplantation into immunodeficient mice and can be further differentiated to generate insulin-producing cells in vitro. Thus, the efficient generation of PDX1+/NKX6-1+ pancreatic progenitors, as demonstrated in this protocol, is of great importance as it provides a platform to study human pancreatic development in vitro and provides a source of cells with the potential of differentiating to &#946; cells that could eventually be used for the treatment of diabetes.

Efficient Differentiation of Pluripotent Stem Cells to NKX6-1+ Pancreatic Progenitors

Here we describe a 4-stage protocol to differentiate human embryonic stem cells to NKX6-1+ pancreatic progenitors in vitro. This protocol can be applied to a variety of human pluripotent stem cell lines.

Pluripotent stem cells have the ability to self renew and differentiate to multiple lineages, making them an attractive source for the generation of ...

Single-cell Photoconversion in Living Intact Zebrafish

Animal and plant tissue is composed of distinct populations of cells. These cells interact over time to build and maintain the tissue and can cause disease when disrupted. Scientists have developed clever techniques to investigate characteristics and natural dynamics of these cells within intact tissue by expressing fluorescent proteins in subsets of cells. However, at times, experiments require more selected visualization of cells within the tissue, sometimes at the single-cell or population-of-cells manner. To achieve this and visualize single cells within a population of cells, scientists have utilized single-cell photoconversion of fluorescent proteins. To demonstrate this technique, we show here how to direct UV light to an Eos-expressing cell of interest in an intact, living zebrafish. We then image those photoconverted Eos+ cells 24 h later to determine how they changed in the tissue. We describe two techniques: single cell photoconversion and photoconversions of populations of cell. These techniques can be used to visualize cell-cell interactions, cell-fate and differentiation, and cell migrations, making it a technique that is applicable in numerous biological questions.

Here, we present a protocol to show how cell photoconversion is achieved through UV exposure to specific areas expressing the fluorescent protein, Eos, in living animals.

Animal and plant tissue is composed of distinct populations of cells. These cells interact over time to build and maintain the tissue and can cause ...

Generation of Scaffold-free, Three-dimensional Insulin Expressing Pancreatoids from Mouse Pancreatic Progenitors In Vitro

The pancreas is a complex organ composed of many different cell types that work together to regulate blood glucose homeostasis and digestion. These cell types include enzyme-secreting acinar cells, an arborized ductal system responsible for the transportation of enzymes to the gut, and hormone-producing endocrine cells. 
Endocrine beta-cells are the sole cell type in the body that produce insulin to lower blood glucose levels. Diabetes, a disease characterized by a loss or the dysfunction of beta-cells, is reaching epidemic proportions. Thus, it is essential to establish protocols to investigate beta-cell development that can be used for screening purposes to derive the drug and cell-based therapeutics. While the experimental investigation of mouse development is essential, in vivo studies are laborious and time-consuming. Cultured cells provide a more convenient platform for screening; however, they are unable to maintain the cellular diversity, architectural organization, and cellular interactions found in vivo. Thus, it is essential to develop new tools to investigate pancreatic organogenesis and physiology.
Pancreatic epithelial cells develop in the close association with mesenchyme from the onset of organogenesis as cells organize and differentiate into the complex, physiologically competent adult organ. The pancreatic mesenchyme provides important signals for the endocrine development, many of which are not well understood yet, thus difficult to recapitulate during the in vitro culture. Here, we describe a protocol to culture three-dimensional, cellular complex mouse organoids that retain mesenchyme, termed pancreatoids. The e10.5 murine pancreatic bud is dissected, dissociated, and cultured in a scaffold-free environment. These floating cells self-assemble with mesenchyme enveloping the developing pancreatoid and a robust number of endocrine beta-cells developing along with the acinar and the duct cells. This system can be used to study the cell fate determination, structural organization, and morphogenesis, cell-cell interactions during organogenesis, or for the drug, small molecule, or genetic screening.

Generation of Scaffold-free, Three-dimensional Insulin Expressing Pancreatoids from Mouse Pancreatic Progenitors In Vitro

Here, we present a protocol to generate insulin expressing 3D murine pancreatoids from free-floating e10.5 dissociated pancreatic progenitors and the associated mesenchyme.

The pancreas is a complex organ composed of many different cell types that work together to regulate blood glucose homeostasis and digestion. These cell ...

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.

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.

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

Methods to Test Endocrine Disruption in Drosophila melanogaster

In recent years there has been growing evidence that all organisms and the environment are exposed to hormone-like chemicals, known as endocrine disruptor chemicals (EDCs). These chemicals may alter the normal balance of endocrine systems and lead to adverse effects, as well as an increasing number of hormonal disorders in the human population or disturbed growth and reduced reproduction in the wildlife species. For some EDCs, there are documented health effects and restrictions on their use. However, for most of them, there is still no scientific evidence in this sense. In order to verify potential endocrine effects of a chemical in the full organism, we need to test it in appropriate model systems, as well as in the fruit fly, Drosophila melanogaster. Here we report detailed in vivo protocols to study endocrine disruption in Drosophila, addressing EDC effects on the fecundity/fertility, developmental timing, and lifespan of the fly. In the last few years, we used these Drosophila life traits to investigate the effects of exposure to 17-&#945;-ethinylestradiol (EE2), bisphenol A (BPA), and bisphenol AF (BPA F). Altogether, these assays covered all Drosophila life stages and made it possible to evaluate endocrine disruption in all hormone-mediated processes. Fecundity/fertility and developmental timing assays were useful to measure the EDC impact on the fly reproductive performance and on developmental stages, respectively. Finally, the lifespan assay involved chronic EDC exposures to adults and measured their survivorship. However, these life traits can also be influenced by several experimental factors that had to be carefully controlled. So, in this work, we suggest a series of procedures we have optimized for the right outcome of these assays. These methods allow scientists to establish endocrine disruption for any EDC or for a mixture of different EDCs in Drosophila, although to identify the endocrine mechanism responsible for the effect, further essays could be needed.

Methods to Test Endocrine Disruption in Drosophila melanogaster

Endocrine disruptor chemicals (EDCs) represent a serious problem for organisms and for natural environments. Drosophila melanogaster represents an ideal model to study EDC effects in vivo. Here, we present methods to investigate endocrine disruption in Drosophila, addressing EDC effects on fecundity, fertility, developmental timing, and lifespan of the fly.

In recent years there has been growing evidence that all organisms and the environment are exposed to hormone-like chemicals, known as endocrine disruptor ...

Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C (UV-C) Damage

The ocular surface is subjected to regular wear and tear due to various environmental factors. Exposure to UV-C radiation constitutes an occupational health hazard. Here, we demonstrate the exposure of primary stem cells from the mouse ocular surface to UV-C radiation. Reactive oxygen species (ROS) formation is the readout of the extent of oxidative stress/damage. In an experimental in vitro setting, it is also essential to assess the percentage of dead cells generated due to oxidative stress. In this article, we will demonstrate the 2&#39;,7&#39;-Dichlorofluoresceindiacetate (DCFDA) staining of UV-C exposed mouse primary ocular surface stem cells and their quantification based on the fluorescent images of DCFDA staining. DCFDA staining directly corresponds to ROS generation. We also demonstrate the quantification of dead and live cells by simultaneous staining with propidium iodide (PI) and Hoechst 3332 respectively and the percentage of DCFDA (ROS positive) and PI positive cells.

Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C UV-C Damage

This protocol demonstrates the simultaneous detection of reactive oxygen species (ROS), live cells, and dead cells in live primary cultures from mouse ocular surface cells. 2&#39;,7&#39;-Dichlorofluoresceindiacetate, propidium iodide, and Hoechst staining are used to assess the ROS, dead cells, and live cells, respectively, followed by imaging and analysis.

The ocular surface is subjected to regular wear and tear due to various environmental factors. Exposure to UV-C radiation constitutes an occupational ...

Efficient Neural Differentiation using Single-Cell Culture of Human Embryonic Stem Cells

In vitro differentiation of human embryonic stem cells (hESCs) has transformed the ability to study human development on both biological and molecular levels and provided cells for use in regenerative applications. Standard approaches for hESC culture using colony type culture to maintain undifferentiated hESCs and embryoid body (EB) and rosette formation for differentiation into different germ layers are inefficient and time-consuming. Presented here is a single-cell culture method using hESCs instead of a colony-type culture. This method allows maintenance of the characteristic features of undifferentiated hESCs, including expression of hESC markers at levels comparable to colony type hESCs. In addition, the protocol presents an efficient method for neural progenitor cell (NPC) generation from single-cell type hESCs that produces NPCs within 1 week. These cells highly express several NPC marker genes and can differentiate into various neural cell types, including dopaminergic neurons and astrocytes. This single-cell culture system for hESCs will be useful in investigating the molecular mechanisms of these processes, studies of certain diseases, and drug discovery screens.

Presented here is a protocol for the generation of a single-cell culture of human embryonic stem cells and their subsequent differentiation into neural progenitor cells. The protocol is simple, robust, scalable, and suitable for drug screening and regenerative medicine applications.

In vitro differentiation of human embryonic stem cells (hESCs) has transformed the ability to study human development on both biological and molecular ...

Multiplexed Single Cell mRNA Sequencing Analysis of Mouse Embryonic Cells

Single cell mRNA sequencing has made significant progress in the last several years and has become an important tool in the field of developmental biology. It has been successfully used to identify rare cell populations, discover novel marker genes, and decode spatial and temporal developmental information. The single cell method has also evolved from the microfluidic based Fluidigm C1 technology to the droplet-based solutions in the last two to three years. Here we used the heart as an example to demonstrate how to profile the mouse embryonic tissue cells using the droplet based scRNA-Seq method. In addition, we have integrated two strategies into the workflow to profile multiple samples in a single experiment. Using one of the integrated methods, we have simultaneously profiled more than 9,000 cells from eight heart samples. These methods will be valuable to the developmental biology field by providing a cost-effective way to simultaneously profile single cells from different genetic backgrounds, developmental stages, or anatomical locations.

Here we presented a multiplexed single cell mRNA sequencing method to profile gene expression in mouse embryonic tissues. The droplet-based single cell mRNA sequencing (scRNA-Seq) method in combination with multiplexing strategies can profile single cells from multiple samples simultaneously, which significantly reduces reagent costs and minimizes experimental batch effects.

Single cell mRNA sequencing has made significant progress in the last several years and has become an important tool in the field of developmental ...

Preparation of Small RNA Libraries for Sequencing from Early Mouse Embryos

MicroRNAs (miRNAs) are important for the complex regulation of cell fate decisions and developmental timing. In vivo studies of the contribution of miRNAs during early development are technically challenging due to the limiting cell number. Moreover, many approaches require a miRNA of interest to be defined in assays such as northern blotting, microarray, and qPCR. Therefore, the expression of many miRNAs and their isoforms have not been studied during early development. Here, we demonstrate a protocol for small RNA sequencing of sorted cells from early mouse embryos to enable relatively unbiased profiling of miRNAs in early populations of neural crest cells. We overcome the challenges of low cell input and size selection during library preparation using amplification and gel-based purification. We identify embryonic age as a variable accounting for variation between replicates and stage-matched mouse embryos must be used to accurately profile miRNAs in biological replicates. Our results suggest that this method can be broadly applied to profile the expression of miRNAs from other lineages of cells. In summary, this protocol can be used to study how miRNAs regulate developmental programs in different cell lineages of the early mouse embryo.

We describe a technique for profiling microRNAs in early mouse embryos. This protocol overcomes the challenge of low cell input and small RNA enrichment. This assay can be used to analyze changes in miRNA expression over time in different cell lineages of the early mouse embryo.

MicroRNAs (miRNAs) are important for the complex regulation of cell fate decisions and developmental timing. In vivo studies of the contribution of miRNAs ...