We thank David M. Patterson and Christopher S. McGinnis from Dr. Zev J. Gartner lab for their kind supply of the lipid based barcoding reagents and suggestions on the experimental steps and data analysis. This work was founded by the National Institutes of Health (HL13347202).

The animal procedure is in accordance with the University of Pittsburgh Institutional Animal Care and Use Committee (IACUC).
1. Mouse Embryonic Heart Dissection and Single Cell Suspension Preparation
NOTE: This step could take a few hours depending on the numbers of embryos to dissect.
<ol>
	<li>To acquire E18.5 embryonic hearts, euthanize a pregnant CD1 mouse by CO2 administration. Use a razor to remove the unwanted hair in the abdominal area and disin...

<ol>
	<li>Raj, A., Van Den Bogaard, P., Rifkin, S. A., Van Oudenaarden, A., Tyagi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+individual+mRNA+molecules+using+multiple+singly+labeled+probes.">Imaging individual mRNA molecules using multiple singly labeled probes.</a> Nature Methods. 5 (10), 877 (2008).</li><li>Tang, F., 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=mRNA-Seq+whole-transcriptome+analysis+of+a+single+cell.">mRNA-Seq whole-transcriptome analysis of a single cell.</a> Nature Methods. 6 (5), 377 (2009).</li><li>Li, G., Plonowska, K., Kuppusamy, R., Sturzu, A., Wu, S. M. <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+cardiovascular+lineage+descendants+at+single-cell+resolution.">Identification of cardiovascular lineage descendants at single-cell resolution.</a> Development. 142 (5), 846-857 (2015).</li><li>DeLaughter, D. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-cell+resolution+of+temporal+gene+expression+during+heart+development.">Single-cell resolution of temporal gene expression during heart development.</a> Developmental Cell. 39 (4), 480-490 (2016).</li><li>Li, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single+cell+expression+analysis+reveals+anatomical+and+cell+cycle-dependent+transcriptional+shifts+during+heart+development.">Single cell expression analysis reveals anatomical and cell cycle-dependent transcriptional shifts during heart development.</a> Development. 146 (12), dev173476 (2019).</li><li>Meilhac, S. M., Buckingham, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+deployment+of+cell+lineages+that+form+the+mammalian+heart.">The deployment of cell lineages that form the mammalian heart.</a> Nature Reviews Cardiology. 1, (2018).</li><li>Liu, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-cell+transcriptomics+reconstructs+fate+conversion+from+fibroblast+to+cardiomyocyte.">Single-cell transcriptomics reconstructs fate conversion from fibroblast to cardiomyocyte.</a> Nature. 551 (7678), 100 (2017).</li><li>Lafzi, A., Moutinho, C., Picelli, S., Heyn, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tutorial:+guidelines+for+the+experimental+design+of+single-cell+RNA+sequencing+studies.">Tutorial: guidelines for the experimental design of single-cell RNA sequencing studies.</a> Nature Protocols. 1, (2018).</li><li>The Tabula Muris Consortium. <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+transcriptomics+of+20+mouse+organs+creates+a+Tabula+Muris.">Single-cell transcriptomics of 20 mouse organs creates a Tabula Muris.</a> Nature. 562 (7727), 367 (2018).</li><li>Gawad, C., Koh, W., Quake, S. R. <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+genome+sequencing:+current+state+of+the+science.">Single-cell genome sequencing: current state of the science.</a> Nature Reviews Genetics. 17 (3), 175 (2016).</li><li>Gr&#252;n, D., van Oudenaarden, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+and+analysis+of+single-cell+sequencing+experiments.">Design and analysis of single-cell sequencing experiments.</a> Cell. 163 (4), 799-810 (2015).</li><li>Ziegenhain, 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=Comparative+analysis+of+single-cell+RNA+sequencing+methods.">Comparative analysis of single-cell RNA sequencing methods.</a> Molecular cell. 65 (4), 631-643 (2017).</li><li>Hashimshony, T., 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=CEL-Seq2:+sensitive+highly-multiplexed+single-cell+RNA-Seq.">CEL-Seq2: sensitive highly-multiplexed single-cell RNA-Seq.</a> Genome Biology. 17 (1), 77 (2016).</li><li>Islam, 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=Characterization+of+the+single-cell+transcriptional+landscape+by+highly+multiplex+RNA-seq.">Characterization of the single-cell transcriptional landscape by highly multiplex RNA-seq.</a> Genome Research. 21 (7), 1160-1167 (2011).</li><li>Macosko, E. Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+parallel+genome-wide+expression+profiling+of+individual+cells+using+nanoliter+droplets.">Highly parallel genome-wide expression profiling of individual cells using nanoliter droplets.</a> Cell. 161 (5), 1202-1214 (2015).</li><li>Klein, A. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Droplet+barcoding+for+single-cell+transcriptomics+applied+to+embryonic+stem+cells.">Droplet barcoding for single-cell transcriptomics applied to embryonic stem cells.</a> Cell. 161 (5), 1187-1201 (2015).</li><li>. Library Prep -Single Cell Gene Expression -Official 10x Genomics Support Available from: <a target="_blank" href="https://support.10xgenomics.com/single-cell-gene-expression/library-prep">https://support.10xgenomics.com/single-cell-gene-expression/library-prep</a> (2018)</li><li>McGinnis, C. 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=MULTI-seq:+sample+multiplexing+for+single-cell+RNA+sequencing+using+lipid-tagged+indices.">MULTI-seq: sample multiplexing for single-cell RNA sequencing using lipid-tagged indices.</a> Nature Methods. 1, (2019).</li><li>Stoeckius, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+hashing+with+barcoded+antibodies+enables+multiplexing+and+doublet+detection+for+single+cell+genomics.">Cell hashing with barcoded antibodies enables multiplexing and doublet detection for single cell genomics.</a> Genome Biology. 19 (1), 224 (2018).</li><li>Chan, M. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+recording+of+mammalian+embryogenesis.">Molecular recording of mammalian embryogenesis.</a> Nature. 570 (7759), 77-82 (2019).</li><li>. Agilent 4200 TapeStation System Available from: <a target="_blank" href="https://www.agilent.com/cs/library/datasheets/public/5991-6029EN.pdf">https://www.agilent.com/cs/library/datasheets/public/5991-6029EN.pdf</a> (2019)</li><li>. SPRIselect User Guide Available from: <a target="_blank" href="https://research.fhcrc.org/content/dam/stripe/hahn/methods/mol_biol/SPRIselect%20User%20Guide.pdf">https://research.fhcrc.org/content/dam/stripe/hahn/methods/mol_biol/SPRIselect%20User%20Guide.pdf</a> (2012)</li><li>. Qubit 4 Fluorometer User Guide Available from: <a target="_blank" href="https://assets.thermofisher.com/TFS-Assets/LSG/manuals/MAN0017209_Qubit_4_Fluorometer_UG.pdf">https://assets.thermofisher.com/TFS-Assets/LSG/manuals/MAN0017209_Qubit_4_Fluorometer_UG.pdf</a> (2018)</li><li>. Agilent High Sensitivity DNA Kit Guide Available from: <a target="_blank" href="https://www.agilent.com/cs/library/usermanuals/public/High%20Sensitivity_DNA_KG.pdf">https://www.agilent.com/cs/library/usermanuals/public/High%20Sensitivity_DNA_KG.pdf</a> (2016)</li><li>Butler, A., Hoffman, P., Smibert, P., Papalexi, E., Satija, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrating+single-cell+transcriptomic+data+across+different+conditions,+technologies,+and+species.">Integrating single-cell transcriptomic data across different conditions, technologies, and species.</a> Nature Biotechnology. 36 (5), 411 (2018).</li><li>Weber, R. J., Liang, S. I., Selden, N. S., Desai, T. A., Gartner, Z. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+targeting+of+fatty-acid+modified+oligonucleotides+to+live+cell+membranes+through+stepwise+assembly.">Efficient targeting of fatty-acid modified oligonucleotides to live cell membranes through stepwise assembly.</a> Biomacromolecules. 15 (12), 4621-4626 (2014).</li><li>. Single Cell Protocols Cell Preparation Guide Available from: <a target="_blank" href="https://support.10xgenomics.com/single-cell-gene-expression/sample-prep">https://support.10xgenomics.com/single-cell-gene-expression/sample-prep</a> (2017)</li></ol>

In this study, we have demonstrated a protocol to analyze single cell transcriptional profiles. We have also provided two optional methods to multiplex samples in the scRNA-Seq workflow. Both methods have proved to be feasible at various labs and provided solutions to run a cost-effective and batch effect-free single cell experiment18,26.
There are a few steps that should be followed carefully when going through the protocol. An ideal ...

The transcriptional profile of each single cell varies among cell populations during embryonic development. Although single molecular in situ hybridization can be used to visualize the expression of a small number of genes1, single cell mRNA sequencing (scRNA-Seq) provides an unbiased approach to illustrate genome-wide expression patterns of genes in single cells. After it was first published in 20092, scRNA-Seq has been applied to study multiple tissues at multiple developmental stages in the recent years3,4,5. Also, as the human cell atlas has launched its developmental-focused projects recently, more single cell data from human embryonic tissues are expected to be generated in the near future.
The heart as the first organ to develop plays a critical role in embryonic development. The heart consists of multiple cell types and the development of each cell type is tightly regulated temporally and spatially. Over the past few years, the origin and cell lineage of cardiac cells at early developmental stages have been characterized6, which provide a tremendous useful navigation tool for understanding congenital heart disease pathogenesis, as well as for developing more technologically advanced methods to stimulate cardiomyocyte regeneration7.
The scRNA-Seq has undergone a rapid expansion in recent years8,9,10. With the newly developed methods, design and analysis of single cell experiments has become more achievable11,12,13,14. The method presented here is a commercial procedure based on the droplet solutions (see Table of Materials)15,16. This method features capturing cells and sets of uniquely barcoded beads in an oil-water emulsion droplet under control of a microfluidic controller system. The rate of cell loading into the droplets is extremely low so that the majority of droplet emulsions contain only one cell17. The procedure&#39;s ingenious design comes from single cell separation into droplet emulsions occurring simultaneously with barcoding, which enables the parallel analysis of individual cells using RNA-Seq on a heterogeneous population.
The incorporation of multiplexing strategies is one of the important additions to the traditional single cell workflow13,14. This addition is very useful in discarding cell doublets, reducing experimental costs, and eliminating batch effects18,19. A lipid based barcoding strategy and an antibody based barcoding strategy (see Table of Materials) are the two mostly used multiplexing methods. Specific barcodes are used to label each sample in both methods, and the labeled samples are then mixed for single cell capturing, library preparation, and sequencing. Afterwards, the pooled sequencing data can be separated by analyzing the barcode sequences (Figure 1)19. However, significant differences exist between the two methods. The lipid based barcoding strategy is based on lipid-modified oligonucleotides, which has not been found to have any cell type preferences. While the antibody based barcoding strategy can only detect the cells expressing the antigen proteins19,20. In addition, it takes about 10 min to stain the lipids but 40 min to stain the antibodies (Figure 1). Furthermore, the lipid-modified oligonucleotides are cheaper than antibody-conjugated oligonucleotides but not commercially available at the time of writing this article. Finally, the lipid-based strategy can multiplex 96 samples in one experiment, but the antibody-based strategy currently can only multiplex 12 samples.
The recommended cell number to multiplex in a single experiment should be lower than 2.5 x 104, otherwise, it will lead to a high percentage of cell doublets and potential ambient mRNA contamination. Through the multiplexing strategies, the cost of single cell capturing, cDNA generation, and library preparation for multiple samples will be reduced to the cost of one sample but the sequencing cost will remain the same.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>10% Tween-20</td>
			<td>Bio-Rad</td>
			<td>1610781</td>
			<td></td>
		</tr>
		<tr>
			<td>10x Chip Holder</td>
			<td>10x Genomics</td>
			<td>120252 330019</td>
			<td></td>
		</tr>
		<tr>
			<td>10x Chromium Controller</td>
			<td>10x Genomics</td>
			<td>120223</td>
			<td></td>
		</tr>
		<tr>
			<td>10x Magnetic Separator</td>
			<td>10x Genomics</td>
			<td>120250 230003</td>
			<td></td>
		</tr>
		<tr>
			<td>10x Vortex Adapter</td>
			<td>10x Genomics</td>
			<td>330002, 120251</td>
			<td></td>
		</tr>
		<tr>
			<td>10x Vortex Clip</td>
			<td>10x Genomics</td>
			<td>120253 230002</td>
			<td></td>
		</tr>
		<tr>
			<td>4200 TapeStation System</td>
			<td>Agilent</td>
			<td>G2991AA</td>
			<td></td>
		</tr>
		<tr>
			<td>Agilent High Sensitivity DNA Kit</td>
			<td>Agilent</td>
			<td>5067-4626</td>
			<td>University of Pittsburgh Health Sciences Sequencing Core</td>
		</tr>
		<tr>
			<td>Barcode Oligo</td>
			<td>Integrated DNA Technologies</td>
			<td>Single-stranded DNA</td>
			<td>25 nmol</td>
		</tr>
		<tr>
			<td>Buffer EB</td>
			<td>Qiagen</td>
			<td>19086</td>
			<td></td>
		</tr>
		<tr>
			<td>CD1 mice</td>
			<td>Chales River</td>
			<td>Strain Code 022</td>
			<td>ordered pregnant mice</td>
		</tr>
		<tr>
			<td>Centrifuge 5424R</td>
			<td>Appendorf</td>
			<td>2231000214</td>
			<td></td>
		</tr>
		<tr>
			<td>Chromium Chip B Single Cell Kit, 48 rxns</td>
			<td>10x Genomics</td>
			<td>1000073</td>
			<td>Store at ambient temperature</td>
		</tr>
		<tr>
			<td>Chromium i7 Multiplex Kit, 96 rxns</td>
			<td>10x Genomics</td>
			<td>120262</td>
			<td>Store at -20 &#176;C</td>
		</tr>
		<tr>
			<td>Chromium Single Cell 3&#39; GEM Kit v3,4 rxns</td>
			<td>10x Genomics</td>
			<td>1000094</td>
			<td>Store at -20 &#176;C</td>
		</tr>
		<tr>
			<td>Chromium Single Cell 3&#39; Library Kit v3</td>
			<td>10x Genomics</td>
			<td>1000095</td>
			<td>Store at -20 &#176;C</td>
		</tr>
		<tr>
			<td>Chromium Single Cell 3&#39; v3 Gel Beads</td>
			<td>10x Genomics</td>
			<td>2000059</td>
			<td>Store at -80 &#176;C</td>
		</tr>
		<tr>
			<td>Collagenase A</td>
			<td>Sigma/Millipore</td>
			<td>10103578001</td>
			<td>Store powder at 4 &#176;C, store at -20 &#176;C after it dissolves</td>
		</tr>
		<tr>
			<td>Collagenase B</td>
			<td>Sigma/Millipore</td>
			<td>11088807001</td>
			<td>Store powder at 4 &#176;C, store at -20 &#176;C after it dissolves</td>
		</tr>
		<tr>
			<td>D1000 ScreenTape</td>
			<td>Agilent</td>
			<td>5067-5582</td>
			<td>University of Pittsburgh Health Sciences Sequencing Core</td>
		</tr>
		<tr>
			<td>DNA LoBind Tube Microcentrifuge Tube, 1.5 mL</td>
			<td>Eppendorf</td>
			<td>022431021</td>
			<td></td>
		</tr>
		<tr>
			<td>DNA LoBind Tube Microcentrifuge Tube, 2.0 mL</td>
			<td>Eppendorf</td>
			<td>022431048</td>
			<td></td>
		</tr>
		<tr>
			<td>Dynabeads MyOne SILANE</td>
			<td>10x Genomics</td>
			<td>2000048</td>
			<td>Store at 4 &#176;C, used in Beads Cleanup Mix (Table 1)</td>
		</tr>
		<tr>
			<td>DynaMag-2 Magnet</td>
			<td>Theromo Scientific</td>
			<td>12321D</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol, Pure (200 Proof, anhydrous)</td>
			<td>Sigma</td>
			<td>E7023-500mL</td>
			<td></td>
		</tr>
		<tr>
			<td>Falcon 15mL High Clarity PP Centrifuge Tube</td>
			<td>Corning Cellgro</td>
			<td>14-959-70C</td>
			<td></td>
		</tr>
		<tr>
			<td>Falcon 50mL High Clarity PP Centrifuge Tube</td>
			<td>Corning Cellgro</td>
			<td>14-959-49A</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum, qualified, United States</td>
			<td>Fisher Scientific</td>
			<td>26140079</td>
			<td>Store at -20 &#176;C</td>
		</tr>
		<tr>
			<td>Finnpipette F1 Multichannel Pipettes, 10-100&#956;l</td>
			<td>Theromo Scientific</td>
			<td>4661020N</td>
			<td></td>
		</tr>
		<tr>
			<td>Finnpipette F1 Multichannel Pipettes, 1-10&#956;l</td>
			<td>Theromo Scientific</td>
			<td>4661000N</td>
			<td></td>
		</tr>
		<tr>
			<td>Flowmi Cell Strainer</td>
			<td>Sigma</td>
			<td>BAH136800040</td>
			<td>Porosity 40 &#956;m, for 1000 uL Pipette Tips, pack of 50 each</td>
		</tr>
		<tr>
			<td>Glycerin (Glycerol), 50% (v/v)</td>
			<td>Ricca Chemical Company</td>
			<td>3290-32</td>
			<td></td>
		</tr>
		<tr>
			<td>HBSS, no calcium, no magnesium</td>
			<td>Thermo Fisher Scientific</td>
			<td>14170112</td>
			<td></td>
		</tr>
		<tr>
			<td>Human TruStain FcX (Fc Receptor Blocking Solution)</td>
			<td>BioLegend</td>
			<td>422301</td>
			<td>Add 5 &#181;l of Human TruStain FcX per million cells in 100 &#181;l staining volume</td>
		</tr>
		<tr>
			<td>Isopropanol (IPA)</td>
			<td>Fisher Scientific</td>
			<td>A464-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Kapa HiFi HotStart ReadyMix (2X)</td>
			<td>Fisher Scientific</td>
			<td>NC0295239</td>
			<td>Store at -20 &#176;C, used in Lipid-tagged barcode library mix (Table 1)</td>
		</tr>
		<tr>
			<td>Lipid Barcode Primer (Multi-seq Primer)</td>
			<td>Integrated DNA Technologies</td>
			<td>Single-stranded DNA</td>
			<td>100 nmol</td>
		</tr>
		<tr>
			<td>Low TE Buffer (10 mM Tris-HCl pH 8.0, 0.1 mM EDTA)</td>
			<td>Thermo Fisher Scientific</td>
			<td>12090-015</td>
			<td></td>
		</tr>
		<tr>
			<td>MasterCycler Pro</td>
			<td>Eppendorf</td>
			<td>950W</td>
			<td></td>
		</tr>
		<tr>
			<td>Nuclease-Free Water (Ambion)</td>
			<td>Thermo Fisher Scientific</td>
			<td>AM9937</td>
			<td></td>
		</tr>
		<tr>
			<td>PCR Tubes 0.2 ml 8-tube strips</td>
			<td>Eppendorf</td>
			<td>951010022</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate-Buffered Saline (PBS) 1X without calcium &#38; magnesium</td>
			<td>Corning Cellgro</td>
			<td>21-040-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate-Buffered Saline (PBS) with 10% Bovine Albumin (alternative to Thermo Fisher product)</td>
			<td>Sigma-Aldrich</td>
			<td>SRE0036</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipet 4-pack (0.1&#8211;2.5&#956;L, 0.5-10&#956;L, 10&#8211;100&#956;L, 100&#8211;1,000&#956;L variable-volume pipettes</td>
			<td>Fisher Scientific</td>
			<td>05-403-151</td>
			<td></td>
		</tr>
		<tr>
			<td>Selection reagent (SPRIselect Reagent Kit)</td>
			<td>Beckman Coulter</td>
			<td>B23318 (60ml)</td>
			<td></td>
		</tr>
		<tr>
			<td>Template Switch Oligo</td>
			<td>10x Genomics</td>
			<td>3000228</td>
			<td>Store at -20 &#176;C, used in Master Mix (Table 1)</td>
		</tr>
		<tr>
			<td>The antibody based barcoding strategy is also known as Cell Hashing</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>The cell browser is Loup Cell Browser</td>
			<td>10x Genomics</td>
			<td></td>
			<td><a href="https://support.10xgenomics.com/single-cell-gene-expression/software/visualization/latest/what-is-loupe-cell-browser" target="_blank">https://support.10xgenomics.com/single-cell-gene-expression/software/visualization/latest/what-is-loupe-cell-browser</a></td>
		</tr>
		<tr>
			<td>The commercial available analysis pipline in step 8.1 is Cell Ranger</td>
			<td>10x Genomics</td>
			<td></td>
			<td><a href="https://support.10xgenomics.com/single-cell-gene-expression/software/pipelines/latest/what-is-cell-ranger" target="_blank">https://support.10xgenomics.com/single-cell-gene-expression/software/pipelines/latest/what-is-cell-ranger</a></td>
		</tr>
		<tr>
			<td>The lipid based barcoding strategy is also known as MULTI-seq</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>The well maintained R platform is Seurat V3</td>
			<td>satijalab</td>
			<td></td>
			<td><a href="https://satijalab.org/seurat/" target="_blank">https://satijalab.org/seurat/</a></td>
		</tr>
		<tr>
			<td>TipOne RPT 0.1-10/20 ul XL ultra low retention filter pipet tip</td>
			<td>USA Scientific</td>
			<td>1180-3710</td>
			<td></td>
		</tr>
		<tr>
			<td>TipOne RPT 1000 ul XL ultra low retention filter pipet tip</td>
			<td>USA Scientific</td>
			<td>1182-1730</td>
			<td></td>
		</tr>
		<tr>
			<td>TipOne RPT 200 ul ultra low retention filter pipet tip</td>
			<td>USA Scientific</td>
			<td>1180-8710</td>
			<td></td>
		</tr>
		<tr>
			<td>TotalSeq-A0301 anti-mouse Hashtag 1 Antibody</td>
			<td>BioLegend</td>
			<td>155801</td>
			<td>0.1 - 1.0 &#181;g of antibody in 100 &#181;l of staining buffer for every 1 million cells</td>
		</tr>
		<tr>
			<td>TotalSeq-A0302 anti-mouse Hashtag 2 Antibody</td>
			<td>BioLegend</td>
			<td>155803</td>
			<td>0.1 - 1.0 &#181;g of antibody in 100 &#181;l of staining buffer for every 1 million cells</td>
		</tr>
		<tr>
			<td>TotalSeq-A0302 anti-mouse Hashtag 3 Antibody</td>
			<td>BioLegend</td>
			<td>155805</td>
			<td>0.1 - 1.0 &#181;g of antibody in 100 &#181;l of staining buffer for every 1 million cells</td>
		</tr>
		<tr>
			<td>TrueSeq RPI primer</td>
			<td>Integrated DNA Technologies</td>
			<td>Single-stranded DNA</td>
			<td>100 nmol, used in Lipid-tagged barcode library mix (Table 1)</td>
		</tr>
		<tr>
			<td>Trypan Blue Solution, 0.4%</td>
			<td>Fisher Scientific</td>
			<td>15250061</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin-EDTA (0.25%), phenol red</td>
			<td>Fisher Scientific</td>
			<td>25200-056</td>
			<td></td>
		</tr>
		<tr>
			<td>Universal I5</td>
			<td>Integrated DNA Technologies</td>
			<td>Single-stranded DNA</td>
			<td>100 nmol</td>
		</tr>
	</tbody>
</table>

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.

In this study, we used mouse embryonic heart as an example to exhibit how multiplexed single cell mRNA sequencing was performed to process the different samples from separate parts of an organ simultaneously. E18.5 CD1 mouse hearts were isolated and dissected into left atrium (LA), right atrium (RA), left ventricle (LV) and right ventricle (RV). The atrial and ventricular cells were then barcoded independently using a lipid-based barcoding procedure and mixed together before GEMs generati...

Watch this Scientific Journal Video about Multiplexed Single Cell mRNA Sequencing Analysis of Mouse Embryonic Cells at JoVE.com

Multiplexed Single Cell mRNA Sequencing Analysis of Mouse Embryonic Cells

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 ...

Single cell mRNA sequencing is widely used to understand the biological processes at a single cell level. The advent of multiplexing strategies has further expanded its amplifications by allowing the profiling of multiple samples in a single experiment, dramatically reducing the cost and avoiding the batch effects. Demonstrating the procedure will be Wei Feng, a postdoc, and Andrew Przysinda, a technician from my lab.After counting, split the cells isolated from embryonic day 18.5 heart chambers into five times 10 to the fifth aliquots and wash the cells two times with fresh PBS per wash. Resuspend the pellets in 180 microliters of PBS per sample and add 20 microliters of anchor barcode stock solution to each tube with gentle mixing. After a five-minute incubation on ice, add 20 microliters of co-anchor barcode stock solution to each tube with gentle mixing for an additional five-minute incubation on ice before washing the cells three times with one milliliter of cold PBS supplemented with 1%bovine serum albumin per wash, then filter the samples into new tubes through one 40-micrometer cell strainer per tube.After counting, assemble chip B into a chip holder, then add 75 microliters of a 50%glycerol solution to the unused wells in row one, 40 microliters to the unused wells in row two, and 280 microliters to the unused wells in row three. Note that a training chip is used here to demonstrate the procedure. Add the appropriate volume of cell suspension and nuclease-free water to the master mix with gentle pipetting.Add 75 microliters of the resulting cell solution to the bottom center of the sample well in row one without bubbles. Vortex the gel beads for 30 seconds before slowly adding 40 microliters of beads to the bottom center of the gel bead well in row two without bubbles. Add 280 microliters of partitioning oil down the sidewall of the partitioning oil well in row three.Attach the gasket to the chip without pressing down on the gasket and keeping the gasket horizontal to avoid wetting the gasket. Load the assembled chip with the gasket in the chromium controller and run the chromium single cell B program. Note that the screen shows chromium training for the training chip but for the real experiments the screen will display chromium single cell B.When the program has completed, immediately remove the chip and discard the gasket.Fold the lid back to expose the wells at a 45-degree angle and check the liquid levels to make sure no clogs are present. Slowly aspirate 100 microliters of gel beads in emulsion from the lowest points of the recovery well and check the uniformity of the beads. Dispense the emulsified beads down the wall of a new PCR tube on ice and place the tube in a thermal cycler for reverse transcription.To prepare the cDNA for amplification, add 125 microliters of recovery agent to the sample at room temperature. No opaque liquid should be observed and avoid pipetting or vortexing. Wait 60 seconds before slowly removing the recovery agent from the bottom of the tube and add 200 microliters of vortex bead cleanup mixture to the sample.Pipette the mixture 10 times before incubating for 10 minutes at room temperature. Next, place the samples onto a magnet in the high position. When the solution clears, remove the supernatant and add 200 microliters of 80%ethanol to the pellet.After 30 seconds, remove the ethanol and repeat the wash two more times. After the last wash, briefly centrifuge the sample and place the tube on the magnet in the low position to allow the sample to air dry for less than two minutes. When the sample has dried, remove the tube from the magnet and add 35.5 microliters of freshly prepared elution solution.After a two-minute incubation at room temperature, place the sample on the magnet in the high position until the solution clears before transferring 35 microliters of the sample to a new tube strip. For cDNA amplification using the lipid-based barcoding strategy, add amplification reaction mixture to the 35-microliter cDNA samples with thorough mixing before briefly centrifuging. At the end of the spin, incubate the sample in the thermal cycler following the appropriate cDNA amplification procedure.Add 120 microliters of select reagent and 100 microliters of ultrapure water to 100 microliters of sample and pipette the resulting 0.6x select reagent 15 times. After a five-minute incubation at room temperature, place the sample on the magnet until the solution becomes clear. Transfer the supernatant to a 1.5-milliliter low bind tube for multiplexing barcoded cDNA library construction.Remember to save both the supernatants and the base as the supernatant's contents assemble barcoded cDNA and the base contents endogenous cDNA. Clean the endogenous cDNA with 80%ethanol and elute the DNA with 40 microliters of elution buffer, then run a quality control check of the endogenous cDNA before preparing an endogenous transcript library. The cDNA concentration should be quantified and qualified before library construction.The constructed libraries, including the endogenous cDNA and barcode libraries, should also be quantified and qualified before sequencing. After sequencing, the barcode expression can be analyzed in each single cell. For example, in this analysis eight groups of single cells that uniquely expressed one type of barcode representing cells from eight different samples were observed.In addition, some cells did not express any barcode and therefore were defined as negative cells, while other cells expressed two different barcodes representing doublets. Using the singlet cells, the cellular heterogeneity and molecular regulations could be assessed by cell type annotation, novel and rare cell type identification, anatomical zone comparative analysis, and gene ontology pathway analysis, such as cell cycle phase separations. It is helpful to image the gel beads in emulsion if you can, as an image will tell you whether or not the procedure has been successful up to this point.The sample multiplexing adds great flexibility in designing your experiments. After watching this demonstration, I hope you will be more confident about starting your own experiments.

multiplexed-single-cell-mrna-sequencing-analysis-mouse-embryonic

Research

JoVE Journal

Developmental Biology

12.5K visualizações.  University of Pittsburgh School of Medicine. O sequenciamento mRNA de célula única é amplamente utilizado para entender os processos biológicos em um único nível celular. O advento das estratégias de multiplexação ampliou ainda mais suas amplificações, permitindo o perfil de várias amostras em um único experimento, reduzindo drasticamente o custo e evitando os efeitos em lote. Demonstrando o procedimento estarão Wei Feng, um pós-doutor, e Andrew Przysinda, um técnico do meu laboratório.Após a contagem, divida as...