Dedicated to the memory of Dr. Rainer Saffrich.
The authors are especially grateful to Jos&#233; Manuel Garc&#237;a-Verdugo and Vicente Herranz-P&#233;rez for performing EM experiments and analysis at the Laboratory of Comparative Neurobiology, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, CIBERNED, Valencia, Spain, which was supported by research funding from the Prometeo Grant for Excellence Research Groups PROMETEO/2019/075. The rest of this work was supported by ACA CELL Biotech GmbH Heidelberg, Germany. 
&#160;

Ethic approvals were obtained when performing the experiments.
1. Isolation of human peripheral blood mononuclear cells (PBMNCs)
<ol>
	<li>Ensure that all donors signed informed consent before blood withdrawing in compliance with institutional guidelines.</li>
	<li>Take 30 mL of blood from healthy donors by trained medical personnel according to the standard protocol.</li>
	<li>Isolate PBMNCs by density gradient media. Use 10 mL of media with 25 mL of 1:1 blood diluted with phosphate buffer saline (PBS), and centrifuge at 300 x g for 30 min.</li>
	<li>Isolate the interphase layer between the plasma and the density gradient media by pipetting. Wash the isolated cells with 5 mL of sterile PBS and centrifuge at 300 x g for 10 min. Repeat twice.</li>
	<li>Count the number of cells by standard methods using a counting chamber.</li>
</ol>
2. Activation of human GPI-anchored glycoprotein by antibody crosslinking on the surface of PBMNCs
<ol>
	<li>Place the 6 x 106 mononuclear cells (MNCs) in 15 mL tubes and perform antibody crosslinking by incubating the cells with human GPI-linked membrane protein-specific antibody (30 &#181;g/mL) for 30 min in PBS with 1% bovine serum albumin (BSA) at 37 &#176;C.</li>
	<li>Replace incubation medium with Iscove&#39;s modified Dulbecco&#39;s medium supplemented with 10% fetal bovine serum (FBS).</li>
	<li>Grow cells in 15 mL polystyrene tubes, put the tubes in an incubator at 37 &#176;C and 5% CO2 for 8-10&#160;days (without shaking). On D5, add an additional 1-2 mL of Iscove&#39;s medium supplemented with 10% FBS to each 15 mL tube.</li>
</ol>
3. Sorting of newly generated dedifferentiated cells
<ol>
	<li>Count cells with an automated cell counter (18 &#181;L cell suspension + 2 &#181;L fluorescence dye) or in a counting chamber.</li>
	<li>Centrifuge cultured cell suspension (5-7 x 106) at 300 x g for 10 min and aspirate the resulting supernatant with a sterile Pasteur pipette.</li>
	<li>Re-suspend the cell pellet in 90 &#181;L of pre-cooled PBS pH 7.2, 0.5% BSA and 2 mM EDTA.</li>
	<li>Add CD45 positive nano-sized magnetic beads (80 &#181;L) to the cell suspension and incubate on ice for 15 min.</li>
	<li>Wash the cells by adding 2 mL of PBS buffer and centrifuge at 300 x g for 10 min.</li>
	<li>Re-suspend the cells in 500 &#181;L of PBS buffer.</li>
	<li>Wash the column with 500 &#181;L of pre-cooled PBS buffer and place it in the magnetic field.</li>
	<li>Place the cell suspension on the column and wash it with 500 &#181;L of PBS buffer (two times) and the centrifuge flow containing CD45 negative cells. Collect them in Iscove&#39;s medium supplemented with 1% BSA.</li>
	<li>Count the cells in the counting chamber.</li>
</ol>
4. Preparing cell culture dishes for neuronal differentiation of newly generated stem cells
<ol>
	<li>Coat the culture vessels with poly-L-ornithine and laminin for growing neuronal cells.</li>
	<li>Place the glass coverslips in 4-well plates and coat it with 1:5 diluted poly-L-ornithine (0.1 mg/mL in ddH2O) in ddH2O. Place the coverslips into a 37 &#176;C incubator for 1 h. Then wash with ddH2O.</li>
	<li>Slowly thaw laminin (0.5-2.0 mg/mL) and add to the top of coverslips. Incubate it at 37 &#176;C for 2 h.</li>
	<li>Prepare neural induction medium N2 consisting of 49 mL of D-MEM/F12, 500 &#181;L of N2 supplement, 400 &#181;L of non-essential amino acids (NEAA), basic FGF solution at 20 ng/mL final concentration (prepared from 100 &#181;g/mL stock solution), and heparin at 2 ng/mL final concentration.</li>
	<li>Remove excess laminin by pipetting and add neuronal medium N2 to culture dishes.</li>
</ol>
5. Culturing of neuronal dedifferentiated blood cells
<ol>
	<li>Culture BD-derived CD45 negative cells on laminin/ornithine-coated glass coverslips for 2 days in an incubator at 37 &#176;C and 5% CO2 in N2 medium to initiate a neuronal differentiation of newly BD-generated cells.</li>
	<li>Culture cells further in neuronal differentiation medium consisting of 48 mL of Neurobasal medium, 500 &#181;L of L-glutamine, 1 mL of B27 Supplement, 500 &#181;L of NEAA, 50 &#181;L of recombinant human glial-derived neurotrophic factor (GDNF) at 5 &#181;g/250 &#181;L in PBS/0.1% BSA, and 50 &#181;L of recombinant human brain derived neurotrophic factor (BDNF) at 5 &#181;g/200 &#181;L in PBS/0.1% BSA and 50 &#181;L of ascorbic acid solution 2.9 g/50 mL in PBS. Place plates in an incubator at 37 &#176;C and 5% CO2.</li>
</ol>
6. Immunofluorescence microscopy analysis of blood-derived neural cells
<ol>
	<li>Culture the cells as described above for 16 days and remove the media.
	<ol>
		<li>Incubate with pre-warmed fixative consisting of 75 mL of sterile water, 4 g of paraformaldehyde. Add 10 N NaOH as needed and stir until the solution clears. Then add 10 mL of 10x PBS, 0.5 mL of MgCl2, 2 mL of 0.5 M EGTA, and 4 g of sucrose. Titrate to pH 7.4 with 6 N HCl, and bring to 100 mL of sterile water for 15 min, according to Marchenko et al.7.</li>
		<li>Discard the fixative and wash the cells 3 times for 5 min each time. Immediately add a freshly made 0.3% Triton X-solution and permeabilize the cells for 5 min. Wash 3 times with PBS and add a blocking solution made by PBS and 5% BSA.</li>
		<li>Block the cells at room temperature on a rocker plate for 1 hour.</li>
		<li>Prepare appropriate dilution of antibodies in 1% BSA/PBS and incubate the cells with antibody dilutions on rocker plate for 1.5 h at room temperature. Wash the cells 3 times with PBS for 5 min each, incubate the cells with DAPI and mount the coverslips with mounting media for visualization on a microscope. 
		NOTE: Directly labeled antibodies used in this experiment are listed in Table of Materials.</li>
	</ol>
	</li>
</ol>
7. Transmission electron microscopy analysis of newly generated cells
<ol>
	<li>Seed the cells for TEM in 8-well chamber slides.</li>
	<li>Fix the cells in 3.5% glutaraldehyde for 1 h at 37 &#176;C, post-fix in 2% OsO4 for an additional hour at room temperature and stain in 2% uranyl acetate in the dark at 4 &#176;C for 2 h 30 min.</li>
	<li>Finally, rinse the cells in distilled water, dehydrate it in ethanol and embed in epoxy resin overnight. The following day transfer the samples to a 70 &#176;C oven for 72 h for resin hardening.</li>
	<li>Detach the embedded cell cultures from chamber slide and glue to araldite blocks.</li>
	<li>Cut serial semi-thin sections (1.5 &#181;m) with a machine, mount onto glass-slides and lightly stain with 1% toluidine blue.</li>
	<li>Glue selected semi-thin sections to araldite blocks and detach them from the glass slide by repeated freezing (in liquid nitrogen) and thawing.</li>
	<li>Prepare ultrathin sections (0.06-0.08 &#181;m) with a machine and further contrast with lead citrate.</li>
	<li>Obtain micrographs by using electron scanning microscope with digital camera.</li>
</ol>

<ol>
	<li>Peng, J., Zeng, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Role+of+Induced+Pluripotent+Stem+Cells+in+Regenerative+Medicine:+Neurodegenerative+Diseases.">The Role of Induced Pluripotent Stem Cells in Regenerative Medicine: Neurodegenerative Diseases.</a> Stem Cell Research and Therapy. 2 (4), 32 (2011).</li><li>Sorells, S. 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=Human+hippocampal+neurogenesis+drops+sharply+in+children+to+undetectable+levels+in+adults.">Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults.</a> Nature. 555 (7696), 377-381 (2018).</li><li>Thomson, J. A., 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=Embryonic+Stem+Cell+Lines+Derived+from+Human+Blastocysts.">Embryonic Stem Cell Lines Derived from Human Blastocysts.</a> Science. 282 (5391), 1145-1147 (1998).</li><li>Takahashi, K., 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=Induction+of+Pluripotent+Stem+Cells+From+Adult+Human+Fibroblast+by+Defined+Factors.">Induction of Pluripotent Stem Cells From Adult Human Fibroblast by Defined Factors.</a> Cell. 131 (5), 861-872 (2007).</li><li>Liu, G. -. H., Yi, F., Suzuki, K., Qu, J., Izpisua Belmonte, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induced+neural+stem+cells:+a+new+tool+for+studying+neural+development+and+neurological+disorders.">Induced neural stem cells: a new tool for studying neural development and neurological disorders.</a> Cell Research. 22 (7), 1087-1091 (2012).</li><li>Becker-Koji&#263;, Z. A., 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=Activation+by+ACA+Induces+Pluripotency+in+Human+Blood+Progenitor+Cells.">Activation by ACA Induces Pluripotency in Human Blood Progenitor Cells.</a> Cell Technologies in Biology and Medicine. 2, 85-101 (2013).</li><li>Marchenko, S., Flanagan, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunocytochemistry:+Human+Neural+Stem+Cells.">Immunocytochemistry: Human Neural Stem Cells.</a> Journal of Visualized Experiments. , e267 (2007).</li><li>Becker-Koji&#263;, Z. A., 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=A+novel+glycoprotein+ACA+is+upstream+regulator+of+human+heamtopoiesis.">A novel glycoprotein ACA is upstream regulator of human heamtopoiesis.</a> Cell Technologies in Biology and Medicine. 2, 69-84 (2013).</li><li>Li, 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=Neurochemical+Regulation+of+the+Expression+and+Function+of+Glial+Fibrillary+Acidic+Protein+in+Astrocytes.">Neurochemical Regulation of the Expression and Function of Glial Fibrillary Acidic Protein in Astrocytes.</a> Glial. 68 (5), 878-897 (2020).</li><li>Melkov&#225;, K., 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=Structure+and+Functions+of+Microtubule+Associated+Proteins+Tau+and+MAP2c:+Similarities+and+Differences.">Structure and Functions of Microtubule Associated Proteins Tau and MAP2c: Similarities and Differences.</a> Biomolecules. 9 (3), 105 (2019).</li><li>Menezes, J. R., Luskin, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+neuron-specific+tubulin+defines+a+novel+population+in+the+proliferative+layers+of+the+developing+telencephalon.">Expression of neuron-specific tubulin defines a novel population in the proliferative layers of the developing telencephalon.</a> Journal of Neuroscience. 14 (9), 5399-5416 (1994).</li><li>Bernal, A., Arranz, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nestin-expressing+progenitor+cells:+function,+identity+and+therapeutic+implications.">Nestin-expressing progenitor cells: function, identity and therapeutic implications.</a> Cellular and Molecular Life Sciences. 75 (12), 2177-2195 (2018).</li></ol>

The corresponding author declares that she is a patent holder related to Novel Human GPI-linked Protein as well as she co-founded and works for ACA CELL Biotech. The other authors declare that they do not have any conflict of interest.

The non-GM method of reprogramming human cells described in this work is based on membrane to nucleus activation of signaling(s) machinery behind the GPI-linked human membrane glycoprotein that initiates the process of dedifferentiation leading to the ex vivo generation and expansion of self-renewing PSCs obtained from non-manipulated human peripheral blood. These cells when cultured in appropriate media are capable of re-differentiation into cells belonging to different germ layers6....

Development of basic and pre-clinical stem cell research methods encourages the clinical application of stem cell-based therapies for neurological diseases. Such potential therapy critically depends on the method for generation of human neural cells leading to functional recovery1.
Neural stem cells (NSCs) self-renew and differentiate into new neurons throughout life in a process called adult neurogenesis. Only very restricted brain areas harbor NSCs competent to generate newborn neurons in adulthood. Such NSCs can give rise to mature neurons, which are involved in learning and memory, thus replacing lost or damaged neurons. Unfortunately, these NSCs are present in restricted amounts and this limited neurogenesis decreases rapidly during juvenile development2. Therefore, other sources of neural cells must be considered in a cell therapy objective.
Degenerative neurological diseases are difficult to cure using standard pharmacological approaches. New therapeutic strategies for embracing many immedicable neurological disorders are based on cell replacement therapies of diseased and injured tissue. NSC transplantation could replace damaged cells and provide beneficial effects. Other sources for neural cell replacement include human embryonic stem cells (ESC), which are derived from the inner cell mass of mammalian blastocysts3, as well as iPSCs4, which have extensive self-renewal capacity like ESCs and are capable to differentiate into various cell lineages. NSCs can also be generated by direct reprogramming from human fibroblasts avoiding pluripotent state5.
Cell replacement therapy is still a challenging issue. Though ESC, fetal, or iPS can be a source for generation of neuronal cells for treating many incurable neurological diseases, autologous adult SCs cell replacement of damaged tissues is a better alternative that circumvents immunological, ethical and safety concerns.
Activation of human GPI-linked protein by antibody-crosslinking via phosphorylation of PLC&#947;/PI3K/Akt/mTor/PTEN initiates a dedifferentiation of blood progenitor cells and generation of blood-derived pluripotent stem cells (BD-PSCs)6. These cells differentiate in vitro toward neuronal cells as confirmed by means of brightfield, immunofluorescence and transmission electron microscopy (TEM) analysis.
In this work we describe the GM-free generation of BD-PSCs and their successful re-differentiation into cells with neuronal phenotype.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Albumin Fraction V</td>
			<td>Roth</td>
			<td>T8444.4</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-GFAP Cy3 conjugate</td>
			<td>Merck Millipore</td>
			<td>MAB3402C3</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-MAP2 Alexa Fluor 555</td>
			<td>Merck Millipore</td>
			<td>MAB3418A5</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Nestin Alexa Fluor 488</td>
			<td>Merck Millipore</td>
			<td>MAB5326A4</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-Tuj1 Alexa Fluor 488</td>
			<td>BD Pharmingen</td>
			<td>560381</td>
			<td></td>
		</tr>
		<tr>
			<td>AO/PI Cell Viability kit</td>
			<td>Biozym</td>
			<td>872045</td>
			<td>Biozym discontinued. The product produced by Logos Biosystems.</td>
		</tr>
		<tr>
			<td>Ascorbic acid 2-phosphate sequimagnes</td>
			<td>Sigma Aldrich</td>
			<td>A8960-5G</td>
			<td></td>
		</tr>
		<tr>
			<td>B27 Serum free 50x</td>
			<td>Fisher Scientific (Gibco)</td>
			<td>11530536</td>
			<td></td>
		</tr>
		<tr>
			<td>Basic FGF solution</td>
			<td>Fisher Scientific (Gibco)</td>
			<td>10647225</td>
			<td></td>
		</tr>
		<tr>
			<td>Biocoll</td>
			<td>Merck Millipore</td>
			<td>L6115-BC</td>
			<td>density gradient media</td>
		</tr>
		<tr>
			<td>BSA Frac V 7.5%</td>
			<td>Gibco</td>
			<td>15260037</td>
			<td></td>
		</tr>
		<tr>
			<td>CD45 MicroBeads</td>
			<td>Miltenyi</td>
			<td>130-045-801</td>
			<td>nano-sized magnetic beads</td>
		</tr>
		<tr>
			<td>Cell counting slides Luna</td>
			<td>Biozym</td>
			<td>872010</td>
			<td>Biozym discontinued. The product produced by Logos Biosystems.</td>
		</tr>
		<tr>
			<td>Chamber Slides Lab-Tek</td>
			<td>Fisher Scientific</td>
			<td>10234121</td>
			<td></td>
		</tr>
		<tr>
			<td>D-MEM/F12</td>
			<td>Merck Millipore</td>
			<td>FG4815-BC</td>
			<td></td>
		</tr>
		<tr>
			<td>Durcupan</td>
			<td>Sigma Aldrich</td>
			<td>44610</td>
			<td>epoxy resin</td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>Merck Millipore</td>
			<td>S0115/1030B</td>
			<td>Discontinued. Available under: TMS-013-B</td>
		</tr>
		<tr>
			<td>GDNF recombinant human</td>
			<td>Fisher Scientific (Gibco)</td>
			<td>10679963</td>
			<td></td>
		</tr>
		<tr>
			<td>GlutaMax 100x</td>
			<td>Gibco</td>
			<td>35050038</td>
			<td>L-glutamine</td>
		</tr>
		<tr>
			<td>Glutaraldehyde grade</td>
			<td>Sigma-Aldrich</td>
			<td>G5882-50ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin sodium cell</td>
			<td>Sigma-Aldrich</td>
			<td>H3149-50KU</td>
			<td></td>
		</tr>
		<tr>
			<td>Human BDNF</td>
			<td>Fisher Scientific (Gibco)</td>
			<td>11588836</td>
			<td></td>
		</tr>
		<tr>
			<td>Iscove (IMDM)</td>
			<td>Biochrom</td>
			<td>FG0465</td>
			<td></td>
		</tr>
		<tr>
			<td>Laminin mouse</td>
			<td>Fisher Scientific (Gibco)</td>
			<td>10267092</td>
			<td></td>
		</tr>
		<tr>
			<td>Lead citrate</td>
			<td>Sigma-Aldrich</td>
			<td>15326-25G</td>
			<td></td>
		</tr>
		<tr>
			<td>Luna FL Automated Cell Counter</td>
			<td>Biozym</td>
			<td>872040</td>
			<td>Biozym discontinued. The product produced by Logos Biosystems.</td>
		</tr>
		<tr>
			<td>MACS Buffer</td>
			<td>Miltenyi</td>
			<td>130-091-221</td>
			<td></td>
		</tr>
		<tr>
			<td>MEM NEAA 100x</td>
			<td>Gibco</td>
			<td>11140035</td>
			<td></td>
		</tr>
		<tr>
			<td>MiniMACS Trenns&#228;ulen</td>
			<td>Miltenyi</td>
			<td>130-042-201</td>
			<td></td>
		</tr>
		<tr>
			<td>Morada digital camera</td>
			<td>Olympus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Multiplatte Nunclon 4 wells</td>
			<td>Fisher Scientific</td>
			<td>10507591</td>
			<td></td>
		</tr>
		<tr>
			<td>N2 Supplement 100x</td>
			<td>Fisher Scientific (Gibco)</td>
			<td>11520536</td>
			<td></td>
		</tr>
		<tr>
			<td>Neurobasal Medium</td>
			<td>Gibco</td>
			<td>10888022</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS sterile</td>
			<td>Roth</td>
			<td>9143.2</td>
			<td></td>
		</tr>
		<tr>
			<td>Poly-L-ornithine</td>
			<td>Sigma-Aldrich</td>
			<td>P4957-50ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Super Glue-3 Loctite</td>
			<td>Henkel</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>TEM FEI Technai G2 Spirit</td>
			<td>FEI Europe</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ultracut UC-6</td>
			<td>Leica</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Uranyl acetate C</td>
			<td>EMS</td>
			<td>22400</td>
			<td></td>
		</tr>
	</tbody>
</table>

gm-free generation of blood-derived neuronal cells

Many human&#160;neurological disorders are caused by degeneration of neurons and glial cells in the brain. Due to limitations in pharmacological and other therapeutic strategies, there is currently no cure available for the injured or diseased brain. Cell replacement appears as a promising therapeutic strategy for neurodegenerative conditions. To this day, neural stem cells (NSCs) have been successfully generated from fetal tissues, human embryonic cells (ES) or induced pluripotent stem cells (iPSC). A process of dedifferentiation was initiated by activation of the novel human GPI-linked glycoprotein, which leads to generation of pluripotent stem cells. These blood-derived pluripotent stem cells (BD-PSCs) differentiate in vitro into cells with a neural phenotype as shown by brightfield and immunofluorescence microscopy. Ultrastructural analysis of these cells by means of electron microscopy confirms their primitive structure as well as neuronal-like morphology and subcellular characteristics.

The results provide evidence that this novel GM-free method is capable of reverting blood progenitor cells to their most primitive state without directly acting on the human genome.
We have previously shown that GPI-linked protein specific antibody crosslinking initiates via PLC&#947;/IP3K/Akt/mTOR/PTEN upregulation of highly conserved developmentally relevant genes such as WNT, NOTCH and C-Kit, thus initiating a process of dedifferentiation that leads to the first step to generation ...

Watch this Scientific Journal Video about GM-Free Generation of Blood-Derived Neuronal Cells at JoVE.com

GM-Free Generation of Blood-Derived Neuronal Cells

We present a genetically modified-free (GM-free) method to obtain cells with a neuronal phenotype from reprogrammed peripheral blood cells. Activation of a signaling pathway linked to novel human GPI-linked protein reveals an efficient GM-free method for obtaining human pluripotent stem cells.

Many human&#160;neurological disorders are caused by degeneration of neurons and glial cells in the brain. Due to limitations in pharmacological and other ...

gm-free-generation-of-blood-derived-neuronal-cells

Research

JoVE Journal

Neuroscience

2.9K Views.  ACA CELL Biotech GmbH. We present a genetically modified-free (GM-free) method to obtain cells with a neuronal phenotype from reprogrammed peripheral blood cells. Activation of a signaling pathway linked to novel human GPI-linked protein reveals an efficient GM-free method for obtaining human pluripotent stem cells. 

Video: GM-Free Generation of Blood-Derived Neuronal Cells

Cryopreservation of Cortical Tissue Blocks for the Generation of Highly Enriched Neuronal Cultures

In this study, we outline a standardized protocol for the successful cryopreservation and thawing of cortical brain tissue blocks to generate highly enriched neuronal cultures. For this protocol the freezing medium used is 10% dimethyl sulfoxide (DMSO) diluted in Hank's Buffered Salt Solution (HBSS). Blocks of cortical tissue are transferred to cryovials containing the freezing medium and slowly frozen at -1&deg;C/min in a rate-controlled freezing container. Post-thaw processing and dissociation of frozen tissue blocks consistently produced neuronal-enriched cultures which exhibited rapid neuritic growth during the first 5 days in culture and significant expansion of the neuronal network within 10 days. Immunocytochemical staining with the astrocytic marker glial fibrillary acidic protein (GFAP) and the neuronal marker beta-tubulin class III, revealed high numbers of neurons and astrocytes in the cultures. Generation of neural precursor cell cultures after tissue block dissociation resulted in rapidly expanding neurospheres, which produced large numbers of neurons and astrocytes under differentiating conditions. This simple cryopreservation protocol allows for the rapid, efficient, and inexpensive preservation of cortical brain tissue blocks, which grants increased flexibility for later generation of neuronal, astrocyte, and neuronal precursor cell cultures.

Here, we describe a method for efficient cryopreservation and thawing of cortical brain tissue blocks to generate highly enriched neuronal cultures. This simple protocol provides flexibility for later generation of neuronal, astrocyte, and neuronal precursor cell cultures.

In this study, we outline a standardized protocol for the successful cryopreservation and thawing of cortical brain tissue blocks to generate highly ...

Generation of Neural Stem Cells from Discarded Human Fetal Cortical Tissue

Neural stem cells (NSCs) reside along the ventricular zone neuroepithelium during the development of the cortical plate. These early progenitors ultimately give rise to intermediate progenitors and later, the various neuronal and glial cell subtypes that form the cerebral cortex. The capacity to generate and expand human NSCs (so called neurospheres) from discarded normal fetal tissue provides a means with which to directly study the functional aspects of normal human NSC development 1-5. This approach can also be directed toward the generation of NSCs from known neurological disorders, thereby affording the opportunity to identify disease processes that alter progenitor proliferation, migration and differentiation 6-9. We have focused on identifying pathological mechanisms in human Down syndrome NSCs that might contribute to the accelerated Alzheimer's disease phenotype 10,11. Neither in vivo nor in vitro mouse models can replicate the identical repertoire of genes located on human chromosome 21. 
Here we use a simple and reliable method to isolate Down syndrome NSCs from aborted human fetal cortices and grow them in culture. The methodology provides specific aspects of harvesting the tissue, dissection with limited anatomical landmarks, cell sorting, plating and passaging of human NSCs. We also provide some basic protocols for inducing differentiation of human NSCs into more selective cell subtypes.

A simple and reliable method on isolation and culture of neural stem cells from discarded human fetal cortical tissue is described. Cultures derived from known human neurological disorders can be used for characterization of pathological cellular and molecular processes, as well as provide a platform to assess pharmacological efficacy.

Neural stem cells (NSCs) reside along the ventricular zone neuroepithelium during the development of the cortical plate. These early progenitors ...

Live-cell Imaging of Sensory Organ Precursor Cells in Intact Drosophila Pupae

Since the discovery of Green Fluorescent Protein (GFP), there has been a revolutionary change in the use of live-cell imaging as a tool for understanding fundamental biological mechanisms. Striking progress has been particularly evident in Drosophila, whose extensive toolkit of mutants and transgenic lines provides a convenient model to study evolutionarily-conserved developmental and cell biological mechanisms. We are interested in understanding the mechanisms that control cell fate specification in the adult peripheral nervous system (PNS) in Drosophila. Bristles that cover the head, thorax, abdomen, legs and wings of the adult fly are individual mechanosensory organs, and have been studied as a model system for understanding mechanisms of Notch-dependent cell fate decisions. Sensory organ precursor (SOP) cells of the microchaetes (or small bristles), are distributed throughout the epithelium of the pupal thorax, and are specified during the first 12 hours after the onset of pupariation. After specification, the SOP cells begin to divide, segregating the cell fate determinant Numb to one daughter cell during mitosis. Numb functions as a cell-autonomous inhibitor of the Notch signaling pathway.
Here, we show a method to follow protein dynamics in SOP cell and its progeny within the intact pupal thorax using a combination of tissue-specific Gal4 drivers and GFP-tagged fusion proteins 1,2.This technique has the advantage over fixed tissue or cultured explants because it allows us to follow the entire development of an organ from specification of the neural precursor to growth and terminal differentiation of the organ. We can therefore directly correlate changes in cell behavior to changes in terminal differentiation. Moreover, we can combine the live imaging technique with mosaic analysis with a repressible cell marker (MARCM) system to assess the dynamics of tagged proteins in mitotic SOPs under mutant or wildtype conditions. Using this technique, we and others have revealed novel insights into regulation of asymmetric cell division and the control of Notch signaling activation in SOP cells (examples include references 1-6,7 ,8).

Live-cell Imaging of Sensory Organ Precursor Cells in Intact Drosophila Pupae

In this video, we describe a method for live cell imaging of asymmetrically dividing sensory organ progenitor cells and epidermal cells in intact Drosophila pupae

Since the discovery of Green Fluorescent Protein (GFP), there has been a revolutionary change in the use of live-cell imaging as a tool for understanding ...

The Neuroblast Assay: An Assay for the Generation and Enrichment of Neuronal Progenitor Cells from Differentiating Neural Stem Cell Progeny Using Flow Cytometry

Neural stem cells (NSCs) can be isolated and expanded in large-scale, using the neurosphere assay and differentiated into the three major cell types of the central nervous system (CNS); namely, astrocytes, oligodendrocytes and neurons. These characteristics make neural stem and progenitor cells an invaluable renewable source of cells for in vitro studies such as drug screening, neurotoxicology and electrophysiology and also for cell replacement therapy in many neurological diseases. In practice, however, heterogeneity of NSC progeny, low production of neurons and oligodendrocytes, and predominance of astrocytes following differentiation limit their clinical applications. Here, we describe a novel methodology for the generation and subsequent purification of immature neurons from murine NSC progeny using fluorescence activated cell sorting (FACS) technology. Using this methodology, a highly enriched neuronal progenitor cell population can be achieved without any noticeable astrocyte and bona fide NSC contamination. The procedure includes differentiation of NSC progeny isolated and expanded from E14 mouse ganglionic eminences using the neurosphere assay, followed by isolation and enrichment of immature neuronal cells based on their physical (size and internal complexity) and fluorescent properties using flow cytometry technology. Overall, it takes 5-7 days to generate neurospheres and 6-8 days to differentiate NSC progeny and isolate highly purified immature neuronal cells.

This video protocol demonstrates a novel method for the generation and subsequent purification of neuronal progenitor cells from a renewable source of neural stem cells (NSCs) based on their physical (size and internal granularity) and fluorescent properties using flow cytometry technology.

Neural stem cells (NSCs) can be isolated and expanded in large-scale, using the neurosphere assay and differentiated into the three major cell types of ...

Fast Micro-iontophoresis of Glutamate and GABA: A Useful Tool to Investigate Synaptic Integration

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of the dendritic tree, which eventually leads to neuronal output of action potentials at the axon. The influence of diverse spatial and temporal parameters of specific synaptic input on neuronal output is currently under investigation, e.g. the distance-dependent attenuation of dendritic inputs, the location-dependent interaction of spatially segregated inputs, the influence of GABAergig inhibition on excitatory integration, linear and non-linear integration modes, and many more.
With fast micro-iontophoresis of glutamate and GABA it is possible to precisely investigate the spatial and temporal integration of glutamatergic excitation and GABAergic inhibition. Critical technical requirements are either a triggered fluorescent lamp, light-emitting diode (LED), or a two-photon scanning microscope to visualize dendritic branches without introducing significant photo-damage of the tissue. Furthermore, it is very important to have a micro-iontophoresis amplifier that allows for fast capacitance compensation of high resistance pipettes. Another crucial point is that no transmitter is involuntarily released by the pipette during the experiment.
Once established, this technique will give reliable and reproducible signals with a high neurotransmitter and location specificity. Compared to glutamate and GABA uncaging, fast iontophoresis allows using both transmitters at the same time but at very distant locations without limitation to the field of view. There are also advantages compared to focal electrical stimulation of axons: with micro-iontophoresis the location of the input site is definitely known and it is sure that only the neurotransmitter of interest is released. However it has to be considered that with micro-iontophoresis only the postsynapse is activated and presynaptic aspects of neurotransmitter release are not resolved. In this article we demonstrate how to set up micro-iontophoresis in brain slice experiments.

In this article we introduce fast micro-iontophoresis of neurotransmitters as a technique to investigate integration of postsynaptic signals with high spatial and temporal precision.

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of ...

A Procedure for Implanting Organized Arrays of Microwires for Single-unit Recordings in Awake, Behaving Animals

In vivo electrophysiological recordings in the awake, behaving animal provide a powerful method for understanding neural signaling at the single-cell level. The technique allows experimenters to examine temporally and regionally specific firing patterns in order to correlate recorded action potentials with ongoing behavior. Moreover, single-unit recordings can be combined with a plethora of other techniques in order to produce comprehensive explanations of neural function. In this article, we describe the anesthesia and preparation for microwire implantation. Subsequently, we enumerate the necessary equipment and surgical steps to accurately insert a microwire array into a target structure. Lastly, we briefly describe the equipment used to record from each individual electrode in the array. The fixed microwire arrays described are well-suited for chronic implantation and allow for longitudinal recordings of neural data in almost any behavioral preparation. We discuss tracing electrode tracks to triangulate microwire positions as well as ways to combine microwire implantation with immunohistochemical techniques in order to increase the anatomical specificity of recorded results.

Implanting organized arrays of microwires for use in single-unit electrophysiological recordings presents a number of technical challenges.&#160;Methods for performing this technique and the equipment necessary are described.&#160;Also, the beneficial use of organized microwire arrays to record from distinct neural subregions with high spatial selectivity is discussed.

In vivo electrophysiological recordings in the awake, behaving animal provide a powerful method for understanding neural signaling at the single-cell ...

Inducing Plasticity of Astrocytic Receptors by Manipulation of Neuronal Firing Rates

Close to two decades of research has established that astrocytes in situ and in vivo express numerous G protein-coupled receptors (GPCRs) that can be stimulated by neuronally-released transmitter. However, the ability of astrocytic receptors to exhibit plasticity in response to changes in neuronal activity has received little attention. Here we describe a model system that can be used to globally scale up or down astrocytic group I metabotropic glutamate receptors (mGluRs) in acute brain slices. Included are methods on how to prepare parasagittal hippocampal slices, construct chambers suitable for long-term slice incubation, bidirectionally manipulate neuronal action potential frequency, load astrocytes and astrocyte processes with fluorescent Ca2+ indicator, and measure changes in astrocytic Gq GPCR activity by recording spontaneous and evoked astrocyte Ca2+ events using confocal microscopy. In essence, a &#8220;calcium roadmap&#8221; is provided for how to measure plasticity of astrocytic Gq GPCRs. Applications of the technique for study of astrocytes are discussed. Having an understanding of how astrocytic receptor signaling is affected by changes in neuronal activity has important implications for both normal synaptic function as well as processes underlying neurological disorders and neurodegenerative disease.

Here we describe an adaptation of protocols used to induce homeostatic plasticity in neurons for the study of plasticity of astrocytic G protein-coupled receptors. Recently used to examine changes in astrocytic group I mGluRs in juvenile mice, the method can be applied to measure scaling of various astrocytic GPCRs, in tissue from adult mice in situ and in vivo, and to gain a better appreciation of the sensitivity of astrocytic receptors to changes in neuronal activity.

Close to two decades of research has established that astrocytes in situ and in vivo express numerous G protein-coupled receptors (GPCRs) that can be ...

Gold Nanorod-assisted Optical Stimulation of Neuronal Cells

Recent studies have demonstrated that nerves can be stimulated in a variety of ways by the transient heating associated with the absorption of infrared light by water in neuronal tissue. This technique holds great potential for replacing or complementing standard stimulation techniques, due to the potential for increased localization of the stimulus and minimization of mechanical contact with the tissue. However, optical approaches are limited by the inability of visible light to penetrate deep into tissues. Moreover, thermal modelling suggests that cumulative heating effects might be potentially hazardous when multiple stimulus sites or high laser repetition rates are used. The protocol outlined below describes an enhanced approach to the infrared stimulation of neuronal cells. The underlying mechanism is based on the transient heating associated with the optical absorption of gold nanorods, which can cause triggering of neuronal cell differentiation and increased levels of intracellular calcium activity. These results demonstrate that nanoparticle absorbers can enhance and/or replace the process of infrared neural stimulation based on water absorption, with potential for future applications in neural prostheses and cell therapies.

This protocol outlines how to use the transient heating associated with the optical absorption of gold nanorods to stimulate differentiation and intracellular calcium activity in neuronal cells. These results potentially open up new applications in neural prostheses and fundamental studies in neuroscience.

Recent studies have demonstrated that nerves can be stimulated in a variety of ways by the transient heating associated with the absorption of infrared ...

Chronic Transcranial Electrical Stimulation and Intracortical Recording in Rats

Transcranial electrical stimulation (TES) is a powerful and relatively simple approach to diffusely influence brain activity either randomly or in a closed-loop event-triggered manner. Although many studies are focusing on the possible benefits and side-effects of TES in healthy and pathologic brains, there are still many fundamental open questions regarding the mechanism of action of the stimulation. Therefore, there is a clear need for a robust and reproducible method to test the acute and the chronic effects of TES in rodents. TES can be combined with regular behavioral, electrophysiological, and imaging techniques to investigate neuronal networks in vivo. The implantation of transcranial stimulation electrodes does not impose extra constraints on the experimental design while it offers a versatile, flexible tool to manipulate brain activity. Here we provide a detailed, step-by-step protocol to fabricate and implant transcranial stimulation electrodes to influence brain activity in a temporally constrained manner for months.

This detailed protocol describes transcranial stimulation electrode placement on the temporal bone in order to investigate the short- and long-term effects of transcranial electrical stimulation in freely moving rats.

Transcranial electrical stimulation (TES) is a powerful and relatively simple approach to diffusely influence brain activity either randomly or in a ...

Neuronal Differentiation from Mouse Embryonic Stem Cells In vitro

The neural differentiation of mouse embryonic stem cells (mESCs) is a potential tool for elucidating the key mechanisms involved in neurogenesis and potentially aid in regenerative medicine. Here, we established an efficient and low cost method for neuronal differentiation from mESCs in vitro, using the strategy of combinatorial screening. Under the conditions defined here, the 2-day embryoid body formation + 6-day retinoic acid induction protocol permits fast and efficient differentiation from mESCs into neural precursor cells (NPCs), as seen by the formation of well-stacked and neurite-like A2lox and 129 derivatives that are Nestin positive. The healthy state of embryoid bodies and the timepoint at which retinoic acid (RA) is applied, as well as the RA concentrations, are critical in the process. In the subsequent differentiation from NPCs into neurons, N2B27 medium II (supplemented by Neurobasal medium) could better support the long term maintenance and maturation of neuronal cells. The presented method is highly efficiency, low cost and easy to operate, and can be a powerful tool for neurobiology and developmental biology research.

Here, we established a low cost and easy to operate method that directs fast and efficient differentiation from embryonic stem cells into neurons. This method is suitable for popularization among laboratories and can be a useful tool for neurological research.

The neural differentiation of mouse embryonic stem cells (mESCs) is a potential tool for elucidating the key mechanisms involved in neurogenesis and ...

GM-Free Generation of Blood-Derived Neuronal Cells

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Chapters in this video

Cryopreservation of Cortical Tissue Blocks for the Generation of Highly Enriched Neuronal Cultures

Generation of Neural Stem Cells from Discarded Human Fetal Cortical Tissue

Live-cell Imaging of Sensory Organ Precursor Cells in Intact Drosophila Pupae

The Neuroblast Assay: An Assay for the Generation and Enrichment of Neuronal Progenitor Cells from Differentiating Neural Stem Cell Progeny Using Flow Cytometry

Fast Micro-iontophoresis of Glutamate and GABA: A Useful Tool to Investigate Synaptic Integration

A Procedure for Implanting Organized Arrays of Microwires for Single-unit Recordings in Awake, Behaving Animals

Inducing Plasticity of Astrocytic Receptors by Manipulation of Neuronal Firing Rates

Gold Nanorod-assisted Optical Stimulation of Neuronal Cells

Chronic Transcranial Electrical Stimulation and Intracortical Recording in Rats

Neuronal Differentiation from Mouse Embryonic Stem Cells In vitro