Name: efficient generation and editing of feeder-free ipscs from human pancreatic cells using the crispr-cas9 system
Uploaded: 2017-11-08T13:00:00
Description: Watch this Scientific Journal Video about Efficient Generation and Editing of Feeder-free IPSCs from Human Pancreatic Cells Using the CRISPR-Cas9 System at JoVE.com

Work in the lab was supported by postdoctoral fellowship grant to Dr. Anjali Nandal, and Exploratory grant from Maryland Stem Cell Research Fund to BT (TEDCO).

1. Reprogramming Protocol
<ol>
	<li>Generation of human iPSC from primary human pancreatic cells
	<ol>
		<li>Coat a 6-well plate with 1.5 mg/mL cold collagen and allow it to gel at 37 &#176;C for 1 h.</li>
		<li>Plate early passage human primary pancreatic cells in Prigrow III medium (~1 - 1.5 &#215; 105 cells) on a collagen coated 6-well plate on day -2 to achieve approximately 2.5 &#215; 105 cells or at least 60% confluency per well on the day of transduction (day 0). For the fi...

<ol>
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Reprogramming of human somatic cells to iPSCs has provided a major boost to the fields of basic biology research, personalized medicine, disease modeling, drug development and regenerative medicine16. Many current and widely used methods of human iPSC generation require the use of virus with the risk of integration into the host genome or episomal vectors with low reprogramming efficiency. Here, we present an efficient method for generating feeder-free iPSCs from human pancreatic cells with Sendai...

The reprogramming of human somatic cells to the pluripotent state by overexpression of reprogramming factors has revolutionized stem cell research with applications in disease modeling, regenerative medicine, and drug development. Several non-viral reprogramming methods are available for delivery of reprogramming factors and generating iPSCs, but the process is labor intensive and not very efficient1. The viral methods, though efficient, are associated with problems of virus integration and tumorigenicity2,3,4. In this manuscript, we report the use of cytoplasmic Sendai virus for delivering reprogramming factors and establishing footprint-free iPSC lines that lack integration of any viral vector sequences into their genomes5. Sendai virus is an RNA virus that is diluted out of cell cytoplasm ~10 passages after infection and produces reprogramming factors in abundance, leading to rapid and efficient reprogramming6,7. The established iPSCs can then be readily transitioned to feeder-free medium&#160;to avoid the use of mouse embryonic fibroblasts (MEFs) as feeder cells8.
In this publication, in addition to outlining the Sendai virus mediated reprogramming, we also describe an improved protocol for editing iPSCs, which has the potential to supply unlimited human cells with desired genetic modifications for research. We have used CRISPR/Cas9 technology for the modification of iPSCs, which is now being used for a wide range of applications including knock-ins and knockouts, large-scale genomic deletions, pooled library screening for gene discovery, genetic engineering of numerous model organisms, and gene therapy9,10,11. This technique involves the formation of complexes of Streptococcus pyogenes-derived Cas9 nuclease and 20-mer guide RNAs that achieve target recognition via base-pairing with genomic target sequence adjacent to 3&#39; nucleotide protospacer adjacent motif (PAM) sequence. The Cas9 nuclease induces a double stranded break ~3 nucleotides from the PAM site, which is subsequently repaired predominantly by non-homologous end joining (NHEJ) pathway leading to insertions or deletions in the open reading frame, and thereby functional knockout of genes12.
Our improved protocol includes the details for culture of human pancreatic cells, their reprogramming on mitotically inactivated mouse embryonic fibroblasts (MEFs) to achieve higher efficiency of reprogramming, subsequent adaptation to feeder-free culture on Matrigel, characterization of established iPSCs, CRISPR guided RNA design and preparation, delivery into iPSCs as RNP complexes, single cell sorting to generate clonal lines of edited iPSCs, easy screening and identification of edits, and characterization of single cell clones. Genomic deletions were efficiently generated in this study by the introduction of Cas9 protein and two CRISPR sgRNA RNP complexes to induce double stranded breaks (DSBs) and deletion of the intervening segment. This method capitalizes on the use of two guides for generating deletions in the open reading frame, high efficiency of NHEJ leading to low number of clones that need to be characterized, and easy preliminary screening of clones by the automated capillary electrophoresis unit, fragment analyzer. These effective genome editing methods to generate human stem cell-based disease models will soon become a standard and routine approach in any stem cell laboratory. Finally, precise genome editing will make it possible to go beyond stem cell disease modeling and potentially could help catalyze cell-based therapies.

<table>
	<tbody>
		<tr>
			<td>Sendai viral vectors - CytoTune-iPS 2.0 Kit</td>
			<td>Invitrogen</td>
			<td>A16517</td>
			<td>Thaw on ice; S No: 1</td>
		</tr>
		<tr>
			<td>Trypsin EDTA</td>
			<td>Gibco Life Tech</td>
			<td>25300-054</td>
			<td>0.05%, 100 ml; S No: 2</td>
		</tr>
		<tr>
			<td>Rock inhibitor (Y-27632)</td>
			<td>Milipore</td>
			<td>SCM075</td>
			<td>Use 10 &#956;M; S No: 3</td>
		</tr>
		<tr>
			<td>DMEM/F-12 medium</td>
			<td>Invitrogen</td>
			<td>11330-032</td>
			<td>S No: 4</td>
		</tr>
		<tr>
			<td>Serum replacement (KSR)</td>
			<td>Gibco</td>
			<td>10828028</td>
			<td>S No: 5</td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Invitrogen</td>
			<td>11960069</td>
			<td>1X; S No: 6</td>
		</tr>
		<tr>
			<td>Fetal bovine serum</td>
			<td>Thermo Scientific</td>
			<td>SH30071.03</td>
			<td>Aliquot; S No: 7</td>
		</tr>
		<tr>
			<td>L-glutamine (Glutamax, 100X), liquid</td>
			<td>Thermo Scientific</td>
			<td>35050061</td>
			<td>1/100; S No: 8</td>
		</tr>
		<tr>
			<td>Non-Essential Amino Acids</td>
			<td>Gibco</td>
			<td>11140-050</td>
			<td>1/100; S No: 9</td>
		</tr>
		<tr>
			<td>2-Mercaptoethanol</td>
			<td>Gibco</td>
			<td>21985023</td>
			<td>55 mM, 1/1,000; S No: 10</td>
		</tr>
		<tr>
			<td>Hausser Hemacytometers</td>
			<td>Hausser Scientific</td>
			<td>02-671-54</td>
			<td>S No: 11</td>
		</tr>
		<tr>
			<td>&#160;0.1% Gelatin Solution</td>
			<td>STEMCELL Technologies</td>
			<td>7903</td>
			<td>Incubate at 37&#186; C for 1 hour; S No: 12</td>
		</tr>
		<tr>
			<td>SSEA-4 antibody</td>
			<td>Santacruz</td>
			<td>sc-21704</td>
			<td>1/100; S No: 13</td>
		</tr>
		<tr>
			<td>TRA-1-81 antibody</td>
			<td>Cell Signaling</td>
			<td>4745S</td>
			<td>1/200; S No: 14</td>
		</tr>
		<tr>
			<td>&#160;OCT4 antibody</td>
			<td>Santa Cruz</td>
			<td>sc-5279</td>
			<td>1/1,000; S No: 15</td>
		</tr>
		<tr>
			<td>Collagen I, Rat Tail</td>
			<td>Life Technologies</td>
			<td>A10483-01</td>
			<td>Keep cold; S No: 16</td>
		</tr>
		<tr>
			<td>Alexa Fluor fluorescent 488/ 568 (secondary antibodies)</td>
			<td>Invitrogen</td>
			<td>A21202/A10042</td>
			<td>1/2,000; S No: 17</td>
		</tr>
		<tr>
			<td>DPBS</td>
			<td>Hyclone</td>
			<td>SH30028LS</td>
			<td>1X; S No: 18</td>
		</tr>
		<tr>
			<td>100-mm tissue culture dish</td>
			<td>Falcon</td>
			<td>353003</td>
			<td>S No: 20</td>
		</tr>
		<tr>
			<td>96-well tissue culture plate</td>
			<td>Falcon</td>
			<td>353078</td>
			<td>S No: 21</td>
		</tr>
		<tr>
			<td>6-well tissue culture plate</td>
			<td>Falcon</td>
			<td>353046</td>
			<td>S No: 22</td>
		</tr>
		<tr>
			<td>Dissecting scope&#160;</td>
			<td>Nikon</td>
			<td>SMZ745</td>
			<td>S No: 23</td>
		</tr>
		<tr>
			<td>Picking hood</td>
			<td>NuAire</td>
			<td>NU-301</td>
			<td>S No: 24</td>
		</tr>
		<tr>
			<td>15&#160;ml Centrifuge Tube</td>
			<td>Greiner Bio-One</td>
			<td>188271</td>
			<td>S No: 25</td>
		</tr>
		<tr>
			<td>50&#160;ml Centrifuge Tube</td>
			<td>Greiner Bio-One</td>
			<td>227261</td>
			<td>S No: 26</td>
		</tr>
		<tr>
			<td>Sodium pyruvate</td>
			<td>Invitrogen</td>
			<td>11360</td>
			<td>S No: 28</td>
		</tr>
		<tr>
			<td>&#946;-mercaptoethanol</td>
			<td>Sigma</td>
			<td>M7522</td>
			<td>S No: 29</td>
		</tr>
		<tr>
			<td>Prigrow III medium</td>
			<td>ABM</td>
			<td>TM003</td>
			<td>S No: 31</td>
		</tr>
		<tr>
			<td>Countess&#8482; Cell Counter</td>
			<td>Invitrogen</td>
			<td>C10227</td>
			<td>S No: 32</td>
		</tr>
		<tr>
			<td>Faxitron X-ray system</td>
			<td>Faxitron</td>
			<td>CellRad</td>
			<td>S No: 33</td>
		</tr>
		<tr>
			<td>Accutase</td>
			<td>Innovative cell Technologies</td>
			<td>AT-104</td>
			<td>S No: 34</td>
		</tr>
		<tr>
			<td>Collagenase</td>
			<td>Life Technologies</td>
			<td>17104019</td>
			<td>1mg/ml stock; S No: 35</td>
		</tr>
		<tr>
			<td>Dispase</td>
			<td>STEMCELL Technologies</td>
			<td>7923</td>
			<td>S No: 36</td>
		</tr>
		<tr>
			<td>hESC qualified matrigel</td>
			<td>BD Biosciences</td>
			<td>354277</td>
			<td>To dilute, use cold DMEM/F-12; S No: 37</td>
		</tr>
		<tr>
			<td>bFGF</td>
			<td>R &#38; D</td>
			<td>233-FB</td>
			<td>Stock 10 ug/ml; S No: 38</td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>EMS</td>
			<td>15710</td>
			<td>4% stock in PBS; S No: 39</td>
		</tr>
		<tr>
			<td>TRA-1-60</td>
			<td>Santa Cruz</td>
			<td>sc-21705</td>
			<td>1/100; S No: 40</td>
		</tr>
		<tr>
			<td>NANOG</td>
			<td>ReproCELL</td>
			<td>RCAB0004P-F</td>
			<td>1/100; S No: 41</td>
		</tr>
		<tr>
			<td>Tween 20</td>
			<td>Sigma</td>
			<td>P9416-100ML</td>
			<td>S No: 42</td>
		</tr>
		<tr>
			<td>Alkaline Phosphatase kit</td>
			<td>Stemgent</td>
			<td>00-0055</td>
			<td>S No: 43</td>
		</tr>
		<tr>
			<td>Cas9 protein</td>
			<td>PNA Bio</td>
			<td>CP01-50</td>
			<td>Thaw and aliquot; S No: 44</td>
		</tr>
		<tr>
			<td>Goat or donkey serum</td>
			<td>Sigma</td>
			<td>D9663/G9023</td>
			<td>S No: 45</td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma</td>
			<td>X100-100ML</td>
			<td>S No: 46</td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Thermo Scientific</td>
			<td>D1306</td>
			<td>S No: 47</td>
		</tr>
		<tr>
			<td>Tris</td>
			<td>Sigma</td>
			<td>9285-100ML</td>
			<td>S No: 48</td>
		</tr>
		<tr>
			<td>NaCL</td>
			<td>Sigma</td>
			<td>S7653-250G</td>
			<td>S No: 49</td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Sigma</td>
			<td>BP2482-500</td>
			<td>S No: 50</td>
		</tr>
		<tr>
			<td>T4 DNA ligase</td>
			<td>NEB</td>
			<td>M0202T</td>
			<td>S No: 51</td>
		</tr>
		<tr>
			<td>Mega Shortscript T7 kit</td>
			<td>Thermo Scientific</td>
			<td>AM1354</td>
			<td>S No: 52</td>
		</tr>
		<tr>
			<td>Mega Clear kit</td>
			<td>Thermo Scientific</td>
			<td>AM1908</td>
			<td>S No: 53</td>
		</tr>
		<tr>
			<td>SMC4</td>
			<td>BD Biosciences</td>
			<td>354357</td>
			<td>S No: 54</td>
		</tr>
		<tr>
			<td>Fibronectin</td>
			<td>STEMCELL Technologies</td>
			<td>7159</td>
			<td>S No: 55</td>
		</tr>
		<tr>
			<td>CloneJET cloning kit</td>
			<td>Thermo Scientific</td>
			<td>K1232</td>
			<td>S No: 56</td>
		</tr>
		<tr>
			<td>Fragment analyzerTM</td>
			<td>Advanced Analytical</td>
			<td></td>
			<td>S No: 57</td>
		</tr>
		<tr>
			<td>mTeSR1 medium kit</td>
			<td>STEMCELL Technologies</td>
			<td>5850</td>
			<td>Warm to room temperature; S No: 58</td>
		</tr>
		<tr>
			<td>Freezing medium mFreSR&#8482;</td>
			<td>STEMCELL Technologies</td>
			<td>5855</td>
			<td>S No: 59</td>
		</tr>
		<tr>
			<td>Freezing medium CryoStor&#174;</td>
			<td>STEMCELL Technologies</td>
			<td>7930</td>
			<td>S No: 60</td>
		</tr>
		<tr>
			<td>MEFs</td>
			<td>Globalstem</td>
			<td>GSC-6301G</td>
			<td>S No: 61</td>
		</tr>
		<tr>
			<td>L-glutamine</td>
			<td>Invitrogen</td>
			<td>25030081</td>
			<td>S No: 62</td>
		</tr>
		<tr>
			<td>Human pancreatic cells</td>
			<td>ABM</td>
			<td>T0159</td>
			<td>S No: 63</td>
		</tr>
		<tr>
			<td>STEMdiff&#8482; Neural Induction Medium</td>
			<td>Stemcell Technologies</td>
			<td>5835</td>
			<td>S No: 64</td>
		</tr>
		<tr>
			<td>RPMI</td>
			<td>Thermofisher</td>
			<td>11875-093</td>
			<td>S No: 65</td>
		</tr>
		<tr>
			<td>2% B27-insulin</td>
			<td>Thermofisher</td>
			<td>A1895601</td>
			<td>S No: 66</td>
		</tr>
		<tr>
			<td>CHIR99021</td>
			<td>Stemcell Technologies</td>
			<td>72052</td>
			<td>S No: 67</td>
		</tr>
		<tr>
			<td>IWP4</td>
			<td>Stemcell Technologies</td>
			<td>72552</td>
			<td>S No: 68</td>
		</tr>
		<tr>
			<td>2% B27</td>
			<td>Thermofisher</td>
			<td>17504044</td>
			<td>S No: 69</td>
		</tr>
		<tr>
			<td>MCDB 131</td>
			<td>Life Technologies</td>
			<td>10372019</td>
			<td>S No: 70</td>
		</tr>
		<tr>
			<td>Sodium bicarbonate</td>
			<td>Sigma-Aldrich</td>
			<td>S8761-100ML</td>
			<td>S No: 71</td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Sigma-Aldrich</td>
			<td>G8270-100G</td>
			<td>S No: 72</td>
		</tr>
		<tr>
			<td>BSA</td>
			<td>Proliant</td>
			<td>68700</td>
			<td>S No: 73</td>
		</tr>
		<tr>
			<td>GDF8</td>
			<td>Pepro-Tech</td>
			<td>120-00</td>
			<td>S No: 74</td>
		</tr>
		<tr>
			<td>TUJ1 antibody</td>
			<td>EMD Milipore</td>
			<td>AB9354</td>
			<td>S No: 75</td>
		</tr>
		<tr>
			<td>NKX2-5 antibody</td>
			<td>Santa Cruz</td>
			<td>Sc-14033</td>
			<td>S No: 76</td>
		</tr>
		<tr>
			<td>SOX17 antibody</td>
			<td>R &#38; D systems</td>
			<td>AF1924</td>
			<td>S No: 77</td>
		</tr>
		<tr>
			<td>Propidium iodide</td>
			<td>Thermo Scientific</td>
			<td>P3566</td>
			<td>S No: 78</td>
		</tr>
		<tr>
			<td>Amaxa 4D-nucleofector&#8482;</td>
			<td>Lonza</td>
			<td>AAF-1002</td>
			<td>S No: 79</td>
		</tr>
		<tr>
			<td>FACSAria II (cell sorter)</td>
			<td>BD biosciences</td>
			<td>SORP UV</td>
			<td>S No: 80</td>
		</tr>
	</tbody>
</table>

efficient generation and editing of feeder-free ipscs from human pancreatic cells using the crispr-cas9 system

Embryonic and induced pluripotent stem cells can self-renew and differentiate into multiple cell types of the body. The pluripotent cells are thus coveted for research in regenerative medicine and are currently in clinical trials for eye diseases, diabetes, heart diseases, and other disorders. The potential to differentiate into specialized cell types coupled with the recent advances in genome editing technologies including the CRISPR/Cas system have provided additional opportunities for tailoring the genome of iPSC for varied applications including disease modeling, gene therapy, and biasing pathways of differentiation, to name a few. Among the available editing technologies, the CRISPR/Cas9 from Streptococcus pyogenes has emerged as a tool of choice for site-specific editing of the eukaryotic genome. The CRISPRs are easily accessible, inexpensive, and highly efficient in engineering targeted edits. The system requires a Cas9 nuclease and a guide sequence (20-mer) specific to the genomic target abutting a 3-nucleotide &#34;NGG&#34; protospacer-adjacent-motif (PAM) for targeting Cas9 to the desired genomic locus, alongside a universal Cas9 binding tracer RNA (together called single guide RNA or sgRNA). Here we present a step-by-step protocol for efficient generation of feeder-independent and footprint-free iPSC and describe methodologies for genome editing of iPSC using the Cas9 ribonucleoprotein (RNP) complexes. The genome editing protocol is effective and can be easily multiplexed by pre-complexing sgRNAs for more than one target with the Cas9 protein and simultaneously delivering into the cells. Finally, we describe a simplified approach for identification and characterization of iPSCs with desired edits. Taken together, the outlined strategies are expected to streamline generation and editing of iPSC for manifold applications.

In this publication, we have followed a simple but efficient protocol for the generation of iPSC from human pancreatic cells using integration or footprint-free Sendai virus vectors. Figure 1A shows a schematic representation of this reprogramming protocol. The human pancreatic cells were purchased commercially, cultured in Prigrow III medium and transduced with Sendai virus as explained above. Transduced spindle shaped pancreatic cells did not show any morph...

Watch this Scientific Journal Video about Efficient Generation and Editing of Feeder-free IPSCs from Human Pancreatic Cells Using the CRISPR-Cas9 System at JoVE.com

Efficient Generation and Editing of Feeder-free IPSCs from Human Pancreatic Cells Using the CRISPR-Cas9 System

This protocol describes in detail the generation of footprint-free induced pluripotent stem cells (iPSCs) from human pancreatic cells in feeder-free conditions, followed by editing using CRISPR/Cas9 ribonucleoproteins and characterization of the modified single-cell clones.

Embryonic and induced pluripotent stem cells can self-renew and differentiate into multiple cell types of the body. The pluripotent cells are thus coveted ...

The overall goal of this procedure is to generate footprint-free induced pluripotent stem cells or IPSCs from human pancreatic cells in feeder-free conditions, then to edit the cells using CRISPR-Cas9 ribonucleoproteins and finally to characterize the modified single cell clones. This method can help answer key questions in the human stem cell genome editing field such as generation of footprint-free IPSCs and editing with CRISPR-Cas9 ribonucleoproteins. The main advantage of this technique is that clonal lines of edited IPSCs can be generated with high reliability and there is no evidence of mosaicism.After coating a six well plate with cold collagen, plate early passage human primary pancreatic cells in Prigrow III medium on day 2 to achieve approximately 2.5 x 10 to the 5 cells or at least 60%confluency per well on the day of transduction or day zero. On the day of transduction after harvesting and counting the cells according to the text protocol, thaw on ice one set of Sendai vector tubes and carefully add the calculated volumes of each tube to 1 mL of prewarmed Prigrow III medium. Gently pipette to mix the solution.Aspirate the Prigrow III from the cells and slowly add the reprogramming virus mixture to the wells. Then incubate the cells in a 37 degree Celsius incubator overnight. Twenty-four hours after transduction, carefully discard the virus mixture on the cells and replace it with fresh Prigrow III medium.On day six, add 1 mL of cell detachment solution to the cells and incubate them for 10 minutes. Then, using Prigrow III with rock inhibitor, plate all the cells on dishes of MEFs prepared the day before. Incubate the cells at 37 degrees Celsius overnight.Observe the plates regularly for the emergence of cell clumps or colonies indicative of reprogrammed cells which will form clonal aggregates with a cobblestone morphology and a big nucleus and nucleoli. Mark the probable IPSC colonies and regularly check them for growth. Almost four weeks following transduction after preparing 24 well MEF plates, prepare matrix membrane by aliquoting it based on the dilution factor on the certificate of analysis.Pick 24-48 colonies and transfer them onto matrix membrane coated 24 well plates with mTeSR1. Incubate the plates for 24 hours and change the medium every day. Refer to the text protocol for additional details.Add 500 mcL of dispase to detach the robust colonies plated on the matrix membrane. After incubating the cells for 20 minutes, plate them again on matrix membrane coated 12 well plates. Expand and characterize the clones using alkaline phosphatase staining, immuno staining and FACS analysis according to the text protocol.To transfect HIPSCs after synthesizing SGRNAs according to the text protocol, prepare nucleofaction master mix for each sample by combining 0.5 mcg of Cas9 protein and 0.5 mcg of each SGRNA in a 22 mcL reaction volume. After aspirating the medium containing rock inhibitor, use 2 mL of RTPBS to wash each well of ISPCs. Then aspirate the PBS and add 1 mL of cell detachment solution.Incubate the plate at 37 degrees Celsius for 10 minutes. Resuspend the cells in 3 mL of mTeSR1 medium and gently pipette up and down to generate a single cell suspension. Transfer the dissociated cells to a 15 mL centrifuge tube containing 5 mL of mTeSR1 medium.To the nucleofection master mix, add 16.4 mcL of P3 primary cell supplement and 3.6 mcL of supplement one from the Nucleofector kit. After counting and spinning the cells, resuspend each unit of 0.5 x 10 to the 6th cells in 22 mcL of the previously prepared transfection master mix. Quickly transfer the cells into the central chamber of one well of a Nucleocuvette strip.Then, place the strip into a Nucleofector device and nucleofect the cells using program CB150. Following nucleofection, quickly add 80 mcL of prewarmed mTeSR1 medium containing 10 micromolar rock inhibitor to each well of the nucleofected cells. Gently mix by pipetting up and down.Gently transfer the cells from the strip to wells of the matrix membrane precoated 12 well plate containing mTeSR1 medium with rock inhibitor. On the second day of incubation after preparing MEF plates, replace the medium on the HIPSCs from mTeSR1 to mTeSR1 supplemented with 1XSMC4 for at least two hours before single cell sorting. Aspirate the medium from HIPSCs and use PBS to gently wash the cells.Then add 500 mcL of cell detachment solution into each well and incubate the cells at 37 degrees Celsius for 10 minutes. Generate a single cell suspension by adding 1 mL of mTeSR1 to each well and gently pipette up and down several times. Sort single cells into individual wells of a previously prepared 96 well plate.Four days after sorting, colony formation should be apparent. At this point, replace the culture medium with HESC medium supplemented with 1X SMC4. After extracting and expanding the target DNA according the text protocol, use a fragment analyzer kit to run the PCR amplified target genomic region of all clones through the gel dye mix per the manufacturer's instructions.Confirm pluripotent IPSC clones according to the text protocol. Before Sendai virus transduction, pancreatic cells show typical spindle-like morphology. Small tight colonies appear on MEFs by day 12 resembling human pluripotent cell colonies.Normally, the fully reprogrammed human IPSC colonies have very clear boundaries and can be picked up by days 23 to 30. A dissociated colony at day 23 is shown here. Presented here is a typical phase contrast image of an IPSC colony after picking and culture in feeder-free conditions after Sendai virus reprogramming of pancreatic cells.Alkaline phosphatase stained red IPSC colonies are on the right. IPSCs were confirmed by immuno staining for the pluripotency markers OCT4 and NANOG as seen in these panels. In this experiment, IPSCs were stained with cell surface markers and FACS analysis was carried out on a single cell suspension.The green peak represents pancreatic IPSCs, and the purple peak contains IPSC negative cells. While attempting this procedure, it is important to remember to maintain aseptic or sterile conditions for cell sorting and cell culture. Following this procedure, other methods like gene targeting in IPSCs and ESCs can be performed, and additional questions can be answered by performing precise genetic modifications.After watching this video, you should have a good understanding of how to reliably generate footprint-free and feeder-free IPSCs and perform genome editing biallelically.

efficient-generation-editing-feeder-free-ipscs-from-human-pancreatic

Research

JoVE Journal

Bioengineering

Therapeutic Gene Delivery and Transfection in Human Pancreatic Cancer Cells using Epidermal Growth Factor Receptor-targeted Gelatin Nanoparticles

More than 32,000 patients are diagnosed with pancreatic cancer in the United States per year and the disease is associated with very high mortality 1. Urgent need exists to develop novel clinically-translatable therapeutic strategies that can improve on the dismal survival statistics of pancreatic cancer patients. Although gene therapy in cancer has shown a tremendous promise, the major challenge is in the development of safe and effective delivery system, which can lead to sustained transgene expression. 
Gelatin is one of the most versatile natural biopolymer, widely used in food and pharmaceutical products. Previous studies from our laboratory have shown that type B gelatin could physical encapsulate DNA, which preserved the supercoiled structure of the plasmid and improved transfection efficiency upon intracellular delivery. By thiolation of gelatin, the sulfhydryl groups could be introduced into the polymer and would form disulfide bond within nanoparticles, which stabilizes the whole complex and once disulfide bond is broken due to the presence of glutathione in cytosol, payload would be released 2-5. Poly(ethylene glycol) (PEG)-modified GENS, when administered into the systemic circulation, provides long-circulation times and preferentially targets to the tumor mass due to the hyper-permeability of the neovasculature by the enhanced permeability and retention effect 6. Studies have shown over-expression of the epidermal growth factor receptor (EGFR) on Panc-1 human pancreatic adenocarcinoma cells 7. In order to actively target pancreatic cancer cell line, EGFR specific peptide was conjugated on the particle surface through a PEG spacer.8
Most anti-tumor gene therapies are focused on administration of the tumor suppressor genes, such as wild-type p53 (wt-p53), to restore the pro-apoptotic function in the cells 9. The p53 mechanism functions as a critical signaling pathway in cell growth, which regulates apoptosis, cell cycle arrest, metabolism and other processes 10. In pancreatic cancer, most cells have mutations in p53 protein, causing the loss of apoptotic activity. With the introduction of wt-p53, the apoptosis could be repaired and further triggers cell death in cancer cells 11. 
Based on the above rationale, we have designed EGFR targeting peptide-modified thiolated gelatin nanoparticles for wt-p53 gene delivery and evaluated delivery efficiency and transfection in Panc-1 cells.

Type B gelatin-based engineered nanovectors system (GENS) was developed for systemic gene delivery and transfection in the treatment of pancreatic cancer. By modification with epidermal growth factor receptor (EGFR) specific peptide on the surface of nanparticles, they could target on EGFR receptor and release plasmid under reducing environment, such as high intracellular glutathione concentrations.

More than 32,000 patients are diagnosed with pancreatic cancer in the United States per year and the disease is associated with very high mortality 1. ...

Development, Expansion, and In vivo Monitoring of Human NK Cells from Human Embryonic Stem Cells (hESCs) and Induced Pluripotent Stem Cells (iPSCs)

We present a method for deriving natural killer (NK) cells from undifferentiated hESCs and iPSCs using a feeder-free approach. This method gives rise to high levels of NK cells after 4 weeks culture and can undergo further 2-log expansion with artificial antigen presenting cells. hESC- and iPSC-derived NK cells developed in this system have a mature phenotype and function. The production of large numbers of genetically modifiable NK cells is applicable for both basic mechanistic as well as anti-tumor studies. Expression of firefly luciferase in hESC-derived NK cells allows a non-invasive approach to follow NK cell engraftment, distribution, and function. We also describe a dual-imaging scheme that allows separate monitoring of two different cell populations to more distinctly characterize their interactions in vivo. This method of derivation, expansion, and dual in vivo imaging provides a reliable approach for producing NK cells and their evaluation which is necessary to improve current NK cell adoptive therapies.

Development, Expansion, and In vivo Monitoring of Human NK Cells from Human Embryonic Stem Cells hESCs and Induced Pluripotent Stem Cells iPSCs

This protocol describes the development, expansion, and in vivo imaging of NK cells derived from hESCs and iPSCs.

We present a method for deriving natural killer (NK) cells from undifferentiated hESCs and iPSCs using a feeder-free approach. This method gives rise to ...

Production of Genetically Engineered Golden Syrian Hamsters by Pronuclear Injection of the CRISPR/Cas9 Complex

The pronuclear (PN) injection technique was first established in mice to introduce foreign genetic materials into the pronuclei of one-cell stage embryos. The introduced genetic material may integrate into the embryonic genome and generate transgenic animals with foreign genetic information following transfer of the injected embryos to foster mothers. Following the success in mice, PN injection has been applied successfully in many other animal species. Recently, PN injection has been successfully employed to introduce reagents with gene-modifying activities, such as the CRISPR/Cas9 system, to achieve site-specific genetic modifications in several laboratory and farm animal species. In addition to mastering the special set of microinjection skills to produce genetically modified animals by PN injection, researchers must understand the reproduction physiology and behavior of the target species, because each species presents unique challenges. For example, golden Syrian hamster embryos have unique handling requirements in vitro such that PN injection techniques were not possible in this species until recent breakthroughs by our group. With our species-modified PN injection protocol, we have succeeded in producing several gene knockout (KO) and knockin (KI) hamsters, which have been used successfully to model human diseases. Here we describe the PN injection procedure for delivering the CRISPR/Cas9 complex to the zygotes of the hamster, the embryo handling conditions, embryo transfer procedures, and husbandry required to produce genetically modified hamsters.

Pronuclear (PN) injection of the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein-9 nuclease (CRISPR/Cas9) system is a highly efficient method for producing genetically engineered golden Syrian hamsters. Herein, we describe the detailed PN injection protocol for the production of gene knockout hamsters with the CRISPR/Cas9 system.

The pronuclear (PN) injection technique was first established in mice to introduce foreign genetic materials into the pronuclei of one-cell stage embryos. ...

Microinjection of Western Corn Rootworm, Diabrotica virgifera virgifera, Embryos for Germline Transformation, or CRISPR/Cas9 Genome Editing

The western corn rootworm (WCR) is an important pest of corn and is well known for its ability to rapidly adapt to pest management strategies. Although RNA interference (RNAi) has proved to be a powerful tool for studying WCR biology, it has its limitations. Specifically, RNAi itself is transient (i.e. does not result in long-term Mendelian inheritance of the associated phenotype), and it requires knowing the DNA sequence of the target gene. The latter can be limiting if the phenotype of interest is controlled by poorly conserved, or even novel genes, because identifying useful targets would be challenging, if not impossible. Therefore, the number of tools in WCR&#39;s genomic toolbox should be expanded by the development of methods that could be used to create stable mutant strains and enable sequence-independent surveys of the WCR genome. Herein, we detail the methods used to collect and microinject precellular WCR embryos with nucleic acids. While the protocols described herein are aimed at the creation of transgenic WCR, CRISPR/Cas9-genome editing could also be performed using the same protocols, with the only difference being the composition of the solution injected into the embryos.

Microinjection of Western Corn Rootworm, Diabrotica virgifera virgifera, Embryos for Germline Transformation, or CRISPR/Cas9 Genome Editing

Here we present protocols for collecting and microinjecting precellular western corn rootworm embryos for the purpose of performing functional-genomic assays such as germline transformation and CRISPR/Cas9-genome editing.

The western corn rootworm (WCR) is an important pest of corn and is well known for its ability to rapidly adapt to pest management strategies. Although ...

Generation of Cationic Nanoliposomes for the Efficient Delivery of In Vitro Transcribed Messenger RNA

The development of messenger RNA (mRNA)-based therapeutics for the treatment of various diseases becomes more and more important because of the positive properties of in vitro transcribed (IVT) mRNA. With the help of IVT mRNA, the de novo synthesis of a desired protein can be induced without changing the physiological state of the target cell. Moreover, protein biosynthesis can be precisely controlled due to the transient effect of IVT mRNA.
For the efficient transfection of cells, nanoliposomes (NLps) may represent a safe and efficient delivery vehicle for therapeutic mRNA. This study describes a protocol to generate safe and efficient cationic NLps consisting of DC-cholesterol and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) as a delivery vector for IVT mRNA. NLps having a defined size, a homogeneous distribution, and a high complexation capacity, and can be produced using the dry-film method. Moreover, we present different test systems to analyze their complexation and transfection efficacies using synthetic enhanced green fluorescent protein (eGFP) mRNA, as well as their effect on cell viability. Overall, the presented protocol provides an effective and safe approach for mRNA complexation, which may advance and improve the administration of therapeutic mRNA.

Generation of Cationic Nanoliposomes for the Efficient Delivery of In Vitro Transcribed Messenger RNA

Here we describe a protocol for the generation of cationic nanoliposomes, which is based on the dry-film method and can be used for the safe and efficient delivery of in vitro transcribed messenger RNA.

The development of messenger RNA (mRNA)-based therapeutics for the treatment of various diseases becomes more and more important because of the positive ...

Purification and Analytics of a Monoclonal Antibody from Chinese Hamster Ovary Cells Using an Automated Microbioreactor System

Monoclonal antibodies (mAbs) are one of the most popular and well-characterized biological products manufactured today. Most commonly produced using Chinese hamster ovary (CHO) cells, culture and process conditions must be optimized to maximize antibody titers and achieve target quality profiles. Typically, this optimization uses automated microscale bioreactors (15 mL) to screen multiple process conditions in parallel. Optimization criteria include culture performance and the critical quality attributes (CQAs) of the monoclonal antibody (mAb) product, which may impact its efficacy and safety. Culture performance metrics include cell growth and nutrient consumption, while the CQAs include the mAb's N-glycosylation and aggregation profiles, charge variants, and molecular weight. This detailed protocol describes how to purify and subsequently analyze HCCF samples produced by an automated microbioreactor system to gain valuable performance metrics and outputs. First, an automated protein A fast protein liquid chromatography (FPLC) method is used to purify the mAb from harvested cell culture samples. Once concentrated, the glycan profiles are analyzed by mass spectrometry using a specific platform (refer to the Table of Materials). Antibody molecular weights and aggregation profiles are determined using size exclusion chromatography-multiple angle light scattering (SEC-MALS), while charge variants are analyzed using microchip capillary zone electrophoresis (mCZE). In addition to the culture performance metrics captured during the bioreactor process (i.e., culture viability, cell counts, and common metabolites including glutamine, glucose, lactate, and ammonia), spent media is analyzed to identify limiting nutrients to improve the feeding strategies and overall process design. Therefore, a detailed protocol for the absolute quantification of amino acids by liquid chromatography-mass spectrometry (LC-MS) of spent media is also described. The methods used in this protocol take advantage of high-throughput platforms that are compatible for large numbers of small-volume samples.

A detailed protocol for the purification and subsequent analysis of a monoclonal antibody from harvested cell culture fluid (HCCF) of automated microbioreactors has been described. Use of analytics to determine critical quality attributes (CQAs) and maximizing limited sample volume to extract vital information is also presented.

Monoclonal antibodies (mAbs) are one of the most popular and well-characterized biological products manufactured today. Most commonly produced using ...

Isolation of Adult Human Dermal Fibroblasts from Abdominal Skin and Generation of Induced Pluripotent Stem Cells Using a Non-Integrating Method

Induced pluripotent stem cells (iPSCs) could be considered, to date, a promising source of pluripotent cells for the management of currently untreatable diseases, for the reconstitution and regeneration of injured tissues and for the development of new drugs. Despite all the advantages related to the use of iPSCs, such as the low risk of rejection, the lessened ethical issues, and the possibility to obtain them from both young and old patients without any difference in their reprogramming potential, problems to overcome are still numerous. In fact, cell reprogramming conducted with viral and integrating viruses can cause infections and the introduction of required genes can induce a genomic instability of the recipient cell, impairing their use in clinic. In particular, there are many concerns about the use of c-Myc gene, well-known from several studies for its mutation-inducing activity. Fibroblasts have emerged as the suitable cell population for cellular reprogramming as they are easy to isolate and culture and are harvested by a minimally invasive skin punch biopsy. The protocol described here provides a detailed step-by-step description of the whole procedure, from sample processing to obtain cell cultures, choice of reagents and supplies, cleaning and preparation, to cell reprogramming by the means of a commercial non-modified RNAs (NM-RNAs)-based reprogramming kit. The chosen reprogramming kit allows an effective reprogramming of human dermal fibroblast to iPSCs and small colonies can be seen as early as 24 h after the first transfection, even with modifications with the respect to the standard datasheet. The reprogramming procedure used in this protocol offers the advantage of a safe reprogramming, without the risk of infections caused by viral vector-based methods, reduces the cellular defense mechanisms, and allows the generation of xeno-free iPSCs, all critical features that are mandatory for further clinical applications.

Cell reprogramming requires the introduction of key genes, which regulate and maintain the pluripotent cell state. The protocol described enables the formation of induced pluripotent stem cells (iPSCs) colonies from human dermal fibroblasts without viral/integrating methods but using non-modified RNAs (NM-RNAs) combined with immune evasion factors reducing cellular defense mechanisms.

Induced pluripotent stem cells (iPSCs) could be considered, to date, a promising source of pluripotent cells for the management of currently untreatable ...

Scalable Generation of Mature Cerebellar Organoids from Human Pluripotent Stem Cells and Characterization by Immunostaining

The cerebellum plays a critical role in the maintenance of balance and motor coordination, and a functional defect in different cerebellar neurons can trigger cerebellar dysfunction. Most of the current knowledge about disease-related neuronal phenotypes is based on postmortem tissues, which makes understanding of disease progression and development difficult. Animal models and immortalized cell lines have also been used as models for neurodegenerative disorders. However, they do not fully recapitulate human disease. Human induced pluripotent stem cells (iPSCs) have great potential for disease modeling and provide a valuable source for regenerative approaches. In recent years, the generation of cerebral organoids from patient-derived iPSCs improved the prospects for neurodegenerative disease modeling. However, protocols that produce large numbers of organoids and a high yield of mature neurons in 3D culture systems are lacking. The protocol presented is a new approach for reproducible and scalable generation of human iPSC-derived organoids under chemically-defined conditions using scalable single-use bioreactors, in which organoids acquire cerebellar identity. The generated organoids are characterized by the expression of specific markers at both mRNA and protein level. The analysis of specific groups of proteins allows the detection of different cerebellar cell populations, whose localization is important for the evaluation of organoid structure. Organoid cryosectioning and further immunostaining of organoid slices are used to evaluate the presence of specific cerebellar cell populations and their spatial organization.

This protocol describes a dynamic culture system to produce controlled size aggregates of human pluripotent stem cells and further stimulate differentiation in cerebellar organoids under chemically-defined and feeder-free conditions using a single-use bioreactor.

The cerebellum plays a critical role in the maintenance of balance and motor coordination, and a functional defect in different cerebellar neurons can ...

Single-Cell Optical Action Potential Measurement in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

Conventional intracellular microelectrode techniques to quantify cardiomyocyte electrophysiology are extremely complex, labor intensive, and typically carried out in low throughput. Rapid and ongoing expansion of induced pluripotent stem cell (iPSC) technology presents a new standard in cardiovascular research and alternate methods are now necessary to increase throughput of electrophysiological data at a single cell level. VF2.1Cl is a recently derived voltage sensitive dye which provides a rapid single channel, high magnitude response to fluctuations in membrane potential. It possesses kinetics superior to those of other existing voltage indicators and makes available functional data equivalent to that of traditional microelectrode techniques. Here, we demonstrate simplified, non-invasive action potential characterization in externally paced human iPSC derived cardiomyocytes using a modular and highly affordable photometry system.

Here we describe optical acquisition and characterization of action potentials from induced pluripotent stem cell derived cardiomyocytes using a high-speed modular photometry system.

Conventional intracellular microelectrode techniques to quantify cardiomyocyte electrophysiology are extremely complex, labor intensive, and typically ...

Microinjection of Corn Planthopper, Peregrinus maidis, Embryos for CRISPR/Cas9 Genome Editing

The corn planthopper, Peregrinus maidis, is&#160;a pest of maize and a vector of several maize viruses. Previously published methods describe the triggering of RNA interference (RNAi) in P. maidis through microinjection of double-stranded RNAs (dsRNAs) into nymphs and adults. Despite the power of RNAi, phenotypes generated via this technique are transient and lack long-term Mendelian inheritance. Therefore, the P. maidis toolbox needs to be expanded to include functional genomic tools that would enable the production of stable mutant strains, opening the door for researchers to bring new control methods to bear on this economically important pest. However, unlike the dsRNAs used for RNAi, the components used in CRISPR/Cas9-based genome editing and germline transformation do not easily cross cell membranes. As a result, plasmid DNAs, RNAs, and/or proteins must be microinjected into embryos before the embryo cellularizes, making the timing of injection a critical factor for success. To that end, an agarose-based egg-lay method was developed to allow embryos to be harvested from P. maidis females at relatively short intervals. Herein are provided detailed protocols for collecting and microinjecting precellular P. maidis embryos with CRISPR components (Cas9 nuclease that has been complexed with guide RNAs), and results of Cas9-based gene knockout of a P. maidis eye-color gene, white, are presented. Although these protocols describe CRISPR/Cas9-genome editing in P. maidis, they can also be used for producing transgenic P. maidis via germline transformation by simply changing the composition of the injection solution.

Microinjection of Corn Planthopper, Peregrinus maidis, Embryos for CRISPR/Cas9 Genome Editing

Herein are protocols for collecting and microinjecting precellular corn planthopper embryos for the purpose of modifying their genome via CRISPR/Cas9-based genome editing or for the addition of marked transposable elements through germline transformation.