Name: single-cell transcriptomic analyses of mouse pancreatic endocrine cells
Uploaded: 2018-09-30T13:00:00
Description: Watch this Scientific Journal Video about Single-cell Transcriptomic Analyses of Mouse Pancreatic Endocrine Cells at JoVE.com

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.

All methods described here have been approved by the Institutional Animal Care and Use Committee (IACUC) of Peking University.
1. Pancreas Isolation
<ol>
	<li>For E17.5 (embryonic day 17.5) embryos:
	<ol>
		<li>Estimate embryonic day 0.5 based on the time point when the vaginal plug appears.</li>
		<li>Sacrifice the pregnant mice by CO2 administration. Spray the abdominal fur with 70% alcohol.</li>
		<li>Make a V-shaped incision with scissors from the genital area...

<ol>
	<li>Gu, G., Dubauskaite, J., Melton, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+evidence+for+the+pancreatic+lineage:+NGN3++cells+are+islet+progenitors+and+are+distinct+from+duct+progenitors.">Direct evidence for the pancreatic lineage: NGN3+ cells are islet progenitors and are distinct from duct progenitors.</a> Development. 129 (10), 2447-2457 (2002).</li><li>Oliver-Krasinski, J. M., Stoffers, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+origin+of+the+beta+cell.">On the origin of the beta cell.</a> Genes &amp; Development. 22 (15), 1998-2021 (1998).</li><li>Dor, Y., Brown, J., Martinez, O. I., Melton, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adult+pancreatic+beta-cells+are+formed+by+self-duplication+rather+than+stem-cell+differentiation.">Adult pancreatic beta-cells are formed by self-duplication rather than stem-cell differentiation.</a> Nature. 429 (6987), 41-46 (2004).</li><li>Smukler, S. 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. E., Westermann, A. J., Gorski, S. A., Vogel, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-cell+RNA-seq:+Advances+and+future+challenges.">Single-cell RNA-seq: Advances and future challenges.</a> Nucleic Acids Research. 42 (14), 8845-8860 (2014).</li><li>Qiu, W. 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=Deciphering+pancreatic+islet+beta+cell+and+alpha+cell+maturation+pathways+and+characteristic+features+at+the+single-cell+level.">Deciphering pancreatic islet beta cell and alpha cell maturation pathways and characteristic features at the single-cell level.</a> Cell Metabolism. 25 (5), 1194-1205 (2017).</li><li>Picelli, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Smart-seq2+for+sensitive+full-length+transcriptome+profiling+in+single+cells.">Smart-seq2 for sensitive full-length transcriptome profiling in single cells.</a> Nature Methods. 10 (11), 1096-1098 (2013).</li><li>Picelli, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Full-length+RNA-seq+from+single+cells+using+Smart-seq2.">Full-length RNA-seq from single cells using Smart-seq2.</a> Nature Protocols. 9 (1), 171-181 (2014).</li><li>Piccand, J., 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=Pak3+promotes+cell+cycle+exit+and+differentiation+of+beta-cells+in+the+embryonic+pancreas+and+is+necessary+to+maintain+glucose+homeostasis+in+adult+mice.">Pak3 promotes cell cycle exit and differentiation of beta-cells in the embryonic pancreas and is necessary to maintain glucose homeostasis in adult mice.</a> Diabetes. 63 (1), 203-215 (2014).</li><li>Veite-Schmahl, M. J., Regan, D. P., Rivers, A. C., Nowatzke, J. F., Kennedy, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissection+of+the+mouse+pancreas+for+histological+analysis+and+metabolic+profiling.">Dissection of the mouse pancreas for histological analysis and metabolic profiling.</a> Journal of Visualized Experiments. (126), (2017).</li><li>Hu, P., Zhang, W., Xin, H., Deng, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+cell+isolation+and+analysis.">Single cell isolation and analysis.</a> Frontiers in Cell and Developmental Biology. 4, 116 (2016).</li><li>Haque, A., Engel, J., Teichmann, S. A., Lonnberg, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+practical+guide+to+single-cell+RNA-sequencing+for+biomedical+research+and+clinical+applications.">A practical guide to single-cell RNA-sequencing for biomedical research and clinical applications.</a> Genome Medicine. 9 (1), 75 (2017).</li><li>. FastQC: A quality control tool for high throughput sequence data Available from: <a target="_blank" href="https://www.bioinformatics.babraham.ac.uk/projects/fastqc/">https://www.bioinformatics.babraham.ac.uk/projects/fastqc/</a> (2010)</li><li>Langmead, B., Salzberg, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+gapped-read+alignment+with+Bowtie+2.">Fast gapped-read alignment with Bowtie 2.</a> Nature Methods. 9 (4), 357-359 (2012).</li><li>Kim, D., 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=TopHat2:+accurate+alignment+of+transcriptomes+in+the+presence+of+insertions,+deletions+and+gene+fusions.">TopHat2: accurate alignment of transcriptomes in the presence of insertions, deletions and gene fusions.</a> Genome Biology. 14 (4), (2013).</li><li>Anders, S., Pyl, P. T., Huber, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HTSeq--a+Python+framework+to+work+with+high-throughput+sequencing+data.">HTSeq--a Python framework to work with high-throughput sequencing data.</a> Bioinformatics. 31 (2), 166-169 (2015).</li><li>Wagner, G. P., Kin, K., Lynch, V. 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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...

Watch this Scientific Journal Video about Single-cell Transcriptomic Analyses of Mouse Pancreatic Endocrine Cells at JoVE.com

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, ...

This method can have answer key questions in the pancreatic islet field about pancreatic islet lineage differentiation, maturation, and the regeneration. The main advantage of this technique is that it allows the collection of single pancreatic islet cells for the generation of high quality single cell RNA sequencing data. The application of this technique extend toward the therapy of diabetes and the other pancreatic endocrine related diseases through the transcriptomic analysis of pancreatic endocrine single cells on the pathological conditions.Visual demonstration of this method is critical as the insertion of the needle into the narrow bile duct of the pancreas for the perfusion can be tricky. For embryonic day 17.5 embryos. After opening the abdominal cavity, use elbow tweezers to transfer the visceral tissue to a six centimeter black bottom dish containing cold PBS.Use forceps to detach the pancreas from the visceral tissue. And place the pancreatic tissue in a 20 milliliter vial containing five milliliters of cold collagenase solution. For post natal day zero to 15 mice, carefully dissect all of the lobes of the pancreas before placing the tissue into the collagenase.For post natal day 18 to 60 mice, first remove the xiphoid and extract the bowel to the right side of the abdominal cavity. Push the left and right medial lobes of the liver to each side to expose the gall bladder and the common bile duct. And clamp the duodenum with a pair of small vessel clamps at the upper and lower positions to flank the site where the bile duct enters the duodenum.Next, load a 5 milliliter syringe equipped with a 30 gauge needle with cold collagenase solution. And use the microscope to insert the needle tip into the gall bladder. Carefully and smoothly manipulate the needle through the common bile duct.And depress the plunger to perfuse the pancreas with one to five milliliters of the collagenase solution according to the size of the mouse. When all of the solution has been perfused, use forceps to immediately transfer the pancreas to a 20 milliliter vial containing five milliliters of fresh cold collagenase solution. When all of the pancreatic tissue has been collected, place the vial in a 37 degree Celsius water bath for three minutes, followed by three to five minutes of gentle shaking.Then filter the digested product through a 0.25 millimeter nylon strainer into a new 50 milliliter centrifuge tube. And use a 20 milliliter syringe containing ice cold PBS to thoroughly wash the strainer. For post natal day 18 to 60 pancreata, centrifuge the filtered sample and resuspend the tissue in 30 milliliters of cold PBS.Then decant the tissue suspension into a six centimeter black bottom dish, and use a 200 microliter pipette and a dissecting microscope to pick the islets for transfer into a 1.5 milliliter microcentrifuge tube containing a small volume of cold PBS. For embryonic day 17.5 post natal day 15 pancreata, centrifuge the filtered pancreatic tissue and resuspend the pellet in trypsin-EDTA solution for a four minute incubation in a 37 degree Celsius water bath. At the end of the incubation, gently try to rate the pellet for one minute with a 200 microliter pipette, followed by the addition of 0.5 times the volume of cold fetal bovine serum with a gentle vortexing to stop the digestion.Then collect the digest by centrifugation and resuspend the cells in 200 microliters of FACS buffer in a 5 milliliter FACS tube for sorting by flow cytometry. For single cell picking and lysis, aliquot freshly prepared cell lysis buffer into eight strip PCR tubes, and transfer a single cell into each. Vortex the samples to lyse the cells for release of the RNA, followed by centrifugation for 30 seconds at four degrees Celsius, and immediate storage on ice.For reverse transcription, incubate the lysates for three minutes at 72 degree Celsius followed by one minute on ice. Briefly centrifuge the samples for 30 seconds at four degree Celsius and add 5.7 microliters of reverse transcription mix to each sample to bring the total volume to 10 microliters for each sample. After gentle vortexing and centrifugation, load the samples into a thermocycler and start the reverse transcription program.For polymerase chain reaction preamplification, or PCR, add 15 microliters of PCR mix to each sample containing the first strand reactions, followed by gentle vortexing and centrifugation. Then load the samples into the thermocycler and start the PCR program. For PCR purification, add 25 microliters of resuspended DNA purification beads to each sample, and mix well by vortexing.Then quickly spin the samples at room temperature to collect the liquid while avoiding settlement of the beads. After five minutes at room temperature, place the samples on an appropriate magnetic stand, carefully removing and discarding the supernatant when the solution is clear. Wash the beads with two 30 second washes in 200 microliters of freshly prepared 80%ethanol per wash.And discard the remaining ethanol after the second wash. When the beads have air dried, add 11 microliters of nuclease-free water to elute the DNA target from the beads, followed by vortexing. Then quickly centrifuge the samples, return the samples to the magnetic stand until the solution is clear and transfer 10 microliters of each sample to a new PCR tube.Successfully amplified cDNA should have a full length above 500 base pairs, and be enriched from 1.5 to two kilo base pairs. Moreover, there is usually a 500 to 600 base pair enrichment of cDNA observed in insulin one RFP plus cells, which may represent the insulin transcripts. However, the cDNA fragments near 100 base pairs are primer dimers, which are usually caused by excessive primers and which must be removed by repeating the DNA purification step.The cDNA fragments between 100 and 500 base pairs usually represent degraded cDNA, which is caused by bad cell status or region problems, such as RNase contamination and should be excluded. After the purification of the cDNA libraries for sequencing, cDNA ranging from 250 to 450 base pairs can be obtained through the addition of DNA purification beads to the first and second rounds of purification. After DNA bead purification, the sequencing quality score should be greater than 30 during the sequencing quality evaluation.To obtain high quality cells for downstream analyses, cells with fewer than 0.5 million mapped reads or with fewer than 4, 000 detected genes are excluded, facilitating the characterization of different groups of cells and the identification of genes that are heterogeneously expressed in different groups after principal component analysis and hierarchical clustering. While attempting this procedure, it's important to remember to perfuse the pancreas quickly before the collagenase digestion to avoid islet over digestion and to maintain RNase free environment during the single cell procedures. Following this procedure, other methods like islet imaging and culture can be performed to facilitate visualization of the islet structure and to examine cellular responses and drug stimulation.After development, this technique paved the way for researchers in the field of pancreatic research to explore the mechanisms of islet lineage development and regeneration, as well as diabetes progression in mammals.

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Research

JoVE Journal

Developmental Biology

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 ...

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 ...

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 ...

Accurate Follicle Enumeration in Adult Mouse Ovaries

Sexually reproducing female mammals are born with their entire lifetime supply of oocytes. Immature, quiescent oocytes are found within primordial follicles, the storage unit of the female germline. They are non-renewable, thus their number at birth and subsequent rate of loss largely dictates the female fertile lifespan. Accurate quantification of primordial follicle numbers in women and animals is essential for determining the impact of medicines and toxicants on the ovarian reserve. It is also necessary for evaluating the need for, and success of, existing and emerging fertility preservation techniques. Currently, no methods exist to accurately measure the number of primordial follicles comprising the ovarian reserve in women. Furthermore, obtaining ovarian tissue from large animals or endangered species for experimentation is often not feasible. Thus, mice have become an essential model for such studies, and the ability to evaluate primordial follicle numbers in whole mouse ovaries is a critical tool. However, reports of absolute follicle numbers in mouse ovaries in the literature are highly variable, making it difficult to compare and/or replicate data. This is due to a number of factors including strain, age, treatment groups, as well as technical differences in the methods of counting employed. In this article, we provide a step-by-step instructional guide for preparing histological sections and counting primordial follicles in mouse ovaries using two different methods: [1] stereology, which relies on the fractionator/optical dissector technique; and [2] the direct count technique. Some of the key advantages and drawbacks of each method will be highlighted so that reproducibility can be improved in the field and to enable researchers to select the most appropriate method for their studies.

Here, we describe, compare, and contrast two different techniques for accurate follicle counting of fixed mouse ovarian tissues.

Sexually reproducing female mammals are born with their entire lifetime supply of oocytes. Immature, quiescent oocytes are found within primordial ...

Transillumination-Assisted Dissection of Specific Stages of the Mouse Seminiferous Epithelial Cycle for Downstream Immunostaining Analyses

Spermatogenesis is a unique differentiation process that ultimately gives rise to one of the most distinct cell types of the body, the sperm. Differentiation of germ cells takes place in the cytoplasmic pockets of somatic Sertoli cells that host 4 to 5 generations of germ cells simultaneously and coordinate and synchronize their development. Therefore, the composition of germ cell types within a cross-section is constant, and these cell associations are also known as stages (I&#8211;XII) of the seminiferous epithelial cycle. Importantly, stages can also be identified from intact seminiferous tubules based on their differential light absorption/scatter characteristics revealed by transillumination, and the fact that the stages follow each other along the tubule in a numerical order. This article describes a transillumination-assisted microdissection method for the isolation of seminiferous tubule segments representing specific stages of mouse seminiferous epithelial cycle. The light absorption pattern of seminiferous tubules is first inspected under a dissection microscope, and then tubule segments representing specific stages are cut and used for downstream applications. Here we describe immunostaining protocols for stage-specific squash preparations and for intact tubule segments. This method allows a researcher to focus on biological events taking place at specific phases of spermatogenesis, thus providing a unique tool for developmental, toxicological, and cytological studies of spermatogenesis and underlying molecular mechanisms.

This protocol describes transillumination-assisted microdissection of segments of adult mouse seminiferous tubules representing specific stages of seminiferous epithelial cycle, and cell types therein, and subsequent immunostaining of squash preparations and intact tubule segments.

Spermatogenesis is a unique differentiation process that ultimately gives rise to one of the most distinct cell types of the body, the sperm. ...

Nuclei Isolation from Mouse Cardiac Progenitor Cells at Single-Cell Resolution

Nuclei Isolation from Mouse Cardiac Progenitor Cells for Epigenome and Gene Expression Profiling at Single-Cell Resolution

The developing heart is a complex structure containing various progenitor cells controlled by complex regulatory mechanisms. The examination of the gene expression and chromatin state of individual cells allows the identification of the cell type and state. Single-cell sequencing approaches have revealed a number of important characteristics of cardiac progenitor cell heterogeneity. However, these methods are generally restricted to fresh tissue, which limits studies with diverse experimental conditions, as the fresh tissue must be processed at once in the same run to reduce the technical variability. Therefore, easy and flexible procedures to produce data from methods such as single-nucleus RNA sequencing (snRNA-seq) and the single-nucleus assay for transposase-accessible chromatin with high-throughput sequencing (snATAC-seq) are needed in this area. Here, we present a protocol to rapidly isolate nuclei for subsequent single-nuclei dual-omics (combined snRNA-seq and snATAC-seq). This method allows the isolation of nuclei from frozen samples of cardiac progenitor cells and can be combined with platforms that use microfluidic chambers.

Author Spotlight: Nuclei Isolation from Mouse Cardiac Progenitor Cells for Epigenome and Gene Expression Profiling at Single-Cell Resolution  

Here, we present a protocol describing cell nuclei preparation. After microdissection and enzymatic dissociation of cardiac tissue into single cells, the progenitor cells were frozen, followed by isolation of pure viable cells, which were used for single-nucleus RNA sequencing and the single-nucleus assay for transposase-accessible chromatin with high-throughput sequencing analyses.

The developing heart is a complex structure containing various progenitor cells controlled by complex regulatory mechanisms. The examination of the gene ...

Setting up the Single Cell Stimulant Delivery System for Real-Time Monitoring of Live Mouse Sperm

To begin, pull borosilicate glass capillaries with an outer diameter of two millimeters and an inner diameter of 1.56 millimeters, following appropriate settings. Prior to filling the capillary before each experiment, use fine tweezers to break open the tip of the capillary. For loading the capillary, use the stimulating solution at three to five times the normal concentration of the stimulant required.With a thin plastic transfer pipette, slowly inject the stimulating solution into the capillary until 3/4 of its length is filled. Eliminate any air bubbles that may form during the filling process by gently flicking the capillary. Then, mount the filled capillary on the micromanipulator.Configure the single cell delivery system settings to provide a 10-second pulse at five psi. Connect the borosilicate capillary mounted on the micromanipulator to the single cell delivery system pipette holder. Apply a brief puff lasting two seconds at a pressure of 20 psi, while observing the capillary tip to confirm that the solution is being dispensed through the tip's end.The setup is now ready for use with microscopy for real-time imaging of a single mouse sperm.