This work is supported by grants from the Swedish Research Council, the Swedish Brain Foundation, the Swedish Stroke Foundation, Region Sk&#229;ne, The Thorsten and Elsa Segerfalk Foundation, and the Swedish Government Initiative for Strategic Research Areas (StemTherapy).

<ol>
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B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+current+state+of+animal+models+in+research:+A+review.">The current state of animal models in research: A review.</a> International Journal of Surgery. 72, 9-13 (2019).</li><li>Akhtar, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+flaws+and+human+harms+of+animal+experimentation.">The flaws and human harms of animal experimentation.</a> Cambridge Quarterly Healthcare Ethics. 24 (4), 407-419 (2015).</li><li>Gonzalez-Ramos, 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=Human+stem+cell-derived+GABAergic+neurons+functionally+integrate+into+human+neuronal+networks.">Human stem cell-derived GABAergic neurons functionally integrate into human neuronal networks.</a> Scientific Reports. 11, 22050 (2021).</li><li>Noraberg, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organotypic+hippocampal+slice+cultures+for+studies+of+brain+damage,+neuroprotection+and+neurorepair.">Organotypic hippocampal slice cultures for studies of brain damage, neuroprotection and neurorepair.</a> Current Drug Targets. 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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organogenesis+in+a+dish:+Modeling+development+and+disease+using+organoid+technologies.">Organogenesis in a dish: Modeling development and disease using organoid technologies.</a> Science. 345 (6194), 1247125 (2014).</li><li>Wang, 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=Organoid+technology+for+brain+and+therapeutics+research.">Organoid technology for brain and therapeutics research.</a> CNS Neuroscience &amp; Therapeutics. 23 (10), 771-778 (2017).</li><li>Wang, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+neurological+diseases+with+human+brain+organoids.">Modeling neurological diseases with human brain organoids.</a> Frontiers in Synaptic Neuroscience. 10, 15 (2018).</li><li>Palma-Tortosa, S., Coll-San Martin, B., Kokaia, Z., Tornero, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuronal+replacement+in+stem+cell+therapy+for+stroke:+Filling+the+gap.">Neuronal replacement in stem cell therapy for stroke: Filling the gap.</a> Frontiers in Cell and Developmental Biology. 9, 662636 (2021).</li></ol>

The authors declare no conflicts of interest.

Obtaining hACtx slices of high enough quality is the most critical step in this protocol. Cortical tissue is obtained from epileptic patients undergoing resective surgery24. The quality of the resected tissue, as well as the exposure time of the tissue between resection and culture, is critical; the faster the tissue is transferred from the surgery room to the laboratory and cut, the more optimal the organotypic culture will be. Ideally, the tissue should be cut and transferred to...

Neurodegenerative disorders, such as Parkinson&#39;s disease, Alzheimer&#39;s disease, or ischemic stroke, are a group of diseases that share the common feature of neuronal malfunction or death. They are heterogeneous in terms of the brain area and neuronal population affected. Unfortunately, treatments for these diseases are scarce or of limited efficacy due to the lack of animal models that mimic what occurs in the human brain1,2. Stem cell therapy is one of the most promising strategies for brain regeneration3. The generation of neuronal progenitors from stem cells from different sources has been greatly developed in recent years4,5. Recent publications have shown that human induced pluripotent stem (iPS) cell-derived long-term self-renewing neuroepithelial-like stem (lt-NES) cells, following a cortical differentiation protocol and after intracortical transplantation in a rat model with ischemic stroke affecting the somatosensory cortex, generate mature cortical neurons. In addition, the graft-derived neurons received afferent and efferent synaptic connections from the host neurons, showing their integration into the rat neuronal network6,7. The graft-derived axons were myelinated and found in different areas of the rat brain, including the peri-infarct area, corpus callosum, and contralateral somatosensory cortex. Most importantly, iPS cell-derived transplantation reversed motor deficits in stroke animals7.
Even if animal models help to study transplant survival, neuronal integration, and the effect of the grafted cells on motor and cognitive functions, information about interaction between human cells (graft-host) is missing in this system8,9. For this reason, a combined method of long-term human brain organotypic culture with the ex vivo transplantation of human iPS cell-derived neuronal progenitors is described here. Human brain organotypic cultures obtained from neurosurgical resections are physiologically relevant 3D models of the brain that allow researchers to increase their understanding of the human central nervous system circuitry and the most accurate way of testing treatments for human brain disorders. However, not enough research has been done in this context, and in most cases, human hippocampal brain organotypic cultures have been used10,11. The cerebral cortex is affected by several neurodegenerative disorders, such as ischemic stroke12 or Alzheimer&#39;s disease13, so it is important to have a human cortical 3D system that allows us to expand our knowledge and to test and validate different therapeutic strategies. Several studies in the last few years have used cultures from adult human cortical (hACtx) tissue to model human brain diseases14,15,16,17,18,19; however, limited information is available in the context of stem cell therapy. Two studies have already demonstrated the feasibility of the system described here. In 2018, human embryonic stem cells programmed with different transcription factors and transplanted into hACtx tissue were shown to give rise to mature cortical neurons that could integrate into adult human cortical networks20. In 2020, the transplantation of lt-NES cells into the human organotypic system revealed their capacity to differentiate into mature, layer-specific cortical neurons with the electrophysiological properties of functional neurons. The grafted neurons established both afferent and efferent synaptic contacts with the human cortical neurons in the adult brain slices, as corroborated by rabies virus retrograde monosynaptic tracing, whole-cell patch-clamp recordings, and immuno-electron microscopy21.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Tissue Cutting and electrophysiology</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Adenosine 5&#39;-triphosphate magnesium salt</td>
			<td>Sigma</td>
			<td>A9187</td>
			<td></td>
		</tr>
		<tr>
			<td>Bath temperature controller&#160;</td>
			<td>Luigs &#38; Neumann</td>
			<td>TC0511354</td>
			<td></td>
		</tr>
		<tr>
			<td>Calcium Chloride dihydrate</td>
			<td>Merck</td>
			<td>102382</td>
			<td></td>
		</tr>
		<tr>
			<td>Carbogen gas</td>
			<td>Air Liquide</td>
			<td>NA</td>
			<td></td>
		</tr>
		<tr>
			<td>Cooler</td>
			<td>Julaba FL 300</td>
			<td>9661012.03</td>
			<td></td>
		</tr>
		<tr>
			<td>D-(+)Glucose</td>
			<td>Sigma-Aldrich</td>
			<td>G7021</td>
			<td></td>
		</tr>
		<tr>
			<td>Double Patch-Clamp amplifier</td>
			<td>HEKA electronic</td>
			<td>EPC10</td>
			<td></td>
		</tr>
		<tr>
			<td>Guanosine 5&#39;-Triphosphate disodium salt</td>
			<td>Millipore</td>
			<td>371701</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>AppliChem</td>
			<td>A1069</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium Chloride hexahydrate</td>
			<td>Sigma-Aldrich</td>
			<td>M2670</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium Sulfate heptahydrate</td>
			<td>Sigma-Aldrich</td>
			<td>230391</td>
			<td></td>
		</tr>
		<tr>
			<td>Patchmaster</td>
			<td>HEKA electronic</td>
			<td>Patchmaster 2x91</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipette Puller</td>
			<td>Sutter</td>
			<td>P-2000</td>
			<td></td>
		</tr>
		<tr>
			<td>Plastic Petri dish</td>
			<td>Any suitable</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium chloride</td>
			<td>Merck</td>
			<td>104936</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium D-gluconate</td>
			<td>ThermoFisher</td>
			<td>B25135</td>
			<td></td>
		</tr>
		<tr>
			<td>Rubber teat + glass pipette</td>
			<td>Any suitable</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Bicarbonate</td>
			<td>Sigma-Aldrich</td>
			<td>S5761</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Chloride</td>
			<td>Sigma-Aldrich</td>
			<td>S7653</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium dihydrogen phosphate monohydrate</td>
			<td>Merck</td>
			<td>106346</td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Sigma-Aldrich</td>
			<td>S7903</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue adhesive: Acryl super glue</td>
			<td>Loctite</td>
			<td>2062278</td>
			<td></td>
		</tr>
		<tr>
			<td>Upright microscope</td>
			<td>Olympus</td>
			<td>BX51WI&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Vibratome&#160;</td>
			<td>Leica</td>
			<td>VT1200 S</td>
			<td></td>
		</tr>
		<tr>
			<td>RINSING SOLUTION</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>D-(+)Glucose</td>
			<td>Sigma-Aldrich</td>
			<td>G7021</td>
			<td></td>
		</tr>
		<tr>
			<td>HBSS (without Ca, Mg, or PhenolRed)</td>
			<td>ThermoFisher Scientific</td>
			<td>14175095</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>AppliChem</td>
			<td>A1069</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin (10,000 U/mL)</td>
			<td>ThermoFisher Scientific</td>
			<td>15-140-122</td>
			<td></td>
		</tr>
		<tr>
			<td>MANTAINANCE AND CULTURE OF HUMAN NEOCORTICAL TISSUE</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>6-well plate</td>
			<td>ThermoFisher Scientific</td>
			<td>140675</td>
			<td></td>
		</tr>
		<tr>
			<td>Alvetex scaffold 6 well insert</td>
			<td>Reinnervate Ltd</td>
			<td>AVP004-96</td>
			<td></td>
		</tr>
		<tr>
			<td>B27 Supplement (50x)</td>
			<td>ThermoFisher Scientific</td>
			<td>17504001</td>
			<td></td>
		</tr>
		<tr>
			<td>BrainPhys without Phenol Red</td>
			<td>StemCell technologies</td>
			<td>#05791</td>
			<td>Referenced as neuronal medium in the text</td>
		</tr>
		<tr>
			<td>Filter units 250 mL or 500 mL</td>
			<td>Corning Sigma</td>
			<td>CLS431096/97</td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>Any suitable</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gentamicin (50 mg/mL)</td>
			<td>ThermoFisher Scientific</td>
			<td>15750037</td>
			<td></td>
		</tr>
		<tr>
			<td>Glutamax Supplement (100x)</td>
			<td>ThermoFisher Scientific</td>
			<td>35050061</td>
			<td>Referenced as L-glutamine in the text</td>
		</tr>
		<tr>
			<td>Rubber teat + Glass pipette</td>
			<td>Any suitable</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>GENERATION OF lt-NES cells</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2-Mercaptoethanol 50 mM</td>
			<td>ThermoFisher Scientific</td>
			<td>31350010</td>
			<td></td>
		</tr>
		<tr>
			<td>Animal Free Recombinant EGF</td>
			<td>Peprotech</td>
			<td>AF-100-15</td>
			<td></td>
		</tr>
		<tr>
			<td>B27 Suplemment (50x)</td>
			<td>Thermo Fisher Scientific</td>
			<td>17504001</td>
			<td></td>
		</tr>
		<tr>
			<td>bFGF</td>
			<td>Peprotech</td>
			<td>AF-100-18B</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Albumin Fraction V (7.5% solution)</td>
			<td>ThermoFisher Scientific</td>
			<td>15260037</td>
			<td></td>
		</tr>
		<tr>
			<td>Cyclopamine, V. calcifornicum</td>
			<td>Calbiochem</td>
			<td># 239803</td>
			<td></td>
		</tr>
		<tr>
			<td>D (+) Glucose solution (45%)</td>
			<td>Sigma</td>
			<td>G8769</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethyl sulfoxide (DMSO)</td>
			<td>Sigma Aldrich</td>
			<td>D2438-10mL</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM/F12</td>
			<td>ThermoFisher Scientific</td>
			<td>11320074</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s Phosphate Buffer Saline (DPBS)</td>
			<td>Thermo Fisher Scientific</td>
			<td>14190-144</td>
			<td>Without calcium and magnesium</td>
		</tr>
		<tr>
			<td>Laminin Mouse Protein, Natural</td>
			<td>Thermo Fisher Scientific</td>
			<td>23017015</td>
			<td></td>
		</tr>
		<tr>
			<td>MEM Non-essential aminoacids solutions (100x)</td>
			<td>ThermoFisher Scientific</td>
			<td>11140050</td>
			<td></td>
		</tr>
		<tr>
			<td>N-2 Supplement (100 x)</td>
			<td>ThermoFisher Scientific</td>
			<td>17502001</td>
			<td></td>
		</tr>
		<tr>
			<td>Poly-L-Ornithine</td>
			<td>Merk</td>
			<td>P3655</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Human BMP-4 Protein</td>
			<td>R&#38;D Systems</td>
			<td>314-BP-010</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Human Wnt-3a Protein</td>
			<td>R&#38;D Systems</td>
			<td>5036-WN</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Pyruvate (100 mM)</td>
			<td>ThermoFisher Scientific</td>
			<td>11360070</td>
			<td></td>
		</tr>
		<tr>
			<td>Soybean Trypsin Inhibitor, powder</td>
			<td>Thermo Fisher Scientific</td>
			<td>17075029</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile deionized water</td>
			<td>MilliQ</td>
			<td></td>
			<td>MilliQ filter system</td>
		</tr>
		<tr>
			<td>Trypsin EDTA (0.25%)</td>
			<td>Sigma</td>
			<td>T4049-500ML</td>
			<td></td>
		</tr>
		<tr>
			<td>EQUIPMENT FOR CELL CULTURE&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Adjustable volume pipettes 10, 100, 200, 1000 &#181;L</td>
			<td>Eppendorf</td>
			<td>Various</td>
			<td></td>
		</tr>
		<tr>
			<td>Basement membrane matrix ESC-qualified (Matrigel)</td>
			<td>Corning</td>
			<td>CLS354277-1EA</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Hettich Centrifugen</td>
			<td>Rotina 420R</td>
			<td>5% CO2, 37 &#176;C</td>
		</tr>
		<tr>
			<td>Incubator</td>
			<td>ThermoForma Steri-Cult CO2</td>
			<td>HEPA Class100</td>
			<td></td>
		</tr>
		<tr>
			<td>Stem cell cutting tool 0.190-0.210 mm</td>
			<td>Vitrolife</td>
			<td>14601</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile tubes</td>
			<td>Sarstedt</td>
			<td>Various</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile Disposable Glass Pasteur Pipettes 150 mm</td>
			<td>VWR</td>
			<td>612-1701</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile pipette tips 0.1-1000 &#160;&#181;L</td>
			<td>Biotix VWR</td>
			<td>Various</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile Serological Pipettes 5, 10, 25, 50 mL</td>
			<td>Costar</td>
			<td>Various</td>
			<td></td>
		</tr>
		<tr>
			<td>T25 flasks Nunc</td>
			<td>ThermoFisher Scientific</td>
			<td>156367</td>
			<td></td>
		</tr>
		<tr>
			<td>IMMUNOHISTOCHEMISTRY</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>488-conjugated AffinityPure Donkey anti-mouse IgG</td>
			<td>Jackson ImmunoReserach</td>
			<td>715-545-151</td>
			<td></td>
		</tr>
		<tr>
			<td>488-conjugated AffinityPure Donkey anti-rabbit IgG</td>
			<td>Jackson ImmunoReserach</td>
			<td>711-545-152</td>
			<td></td>
		</tr>
		<tr>
			<td>488-conjugated AffinityPure Donkey anti-chicken IgG</td>
			<td>Jackson ImmunoReserach</td>
			<td>703-545-155</td>
			<td></td>
		</tr>
		<tr>
			<td>Alexa fluor 647-conjugated Streptavidin</td>
			<td>Jackson ImmunoReserach</td>
			<td>016-600-084</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin</td>
			<td>Jackson ImmunoReserach</td>
			<td>001-000-162</td>
			<td></td>
		</tr>
		<tr>
			<td>Chicken anti-GFP</td>
			<td>Merk Millipore</td>
			<td>AB16901</td>
			<td></td>
		</tr>
		<tr>
			<td>Chicken anti-MAP2&#160;</td>
			<td>Abcam</td>
			<td>ab5392</td>
			<td></td>
		</tr>
		<tr>
			<td>Cy3-conjugated AffinityPure Donkey anti-chicken IgG</td>
			<td>Jackson ImmunoReserach</td>
			<td>703-165-155</td>
			<td></td>
		</tr>
		<tr>
			<td>Cy3-conjugated AffinityPure Donkey anti-goat IgG</td>
			<td>Jackson ImmunoReserach</td>
			<td>705-165-147</td>
			<td></td>
		</tr>
		<tr>
			<td>Cy3-conjugated AffinityPure Donkey anti-mouse IgG</td>
			<td>Jackson ImmunoReserach</td>
			<td>715-165-151</td>
			<td></td>
		</tr>
		<tr>
			<td>Diazabicyclooctane (DABCO)</td>
			<td>Sigma Aldrich</td>
			<td>D27802</td>
			<td>Mounting media</td>
		</tr>
		<tr>
			<td>Goat anti-AIF1 (C-terminal)&#160;</td>
			<td>Biorad</td>
			<td>AHP2024</td>
			<td></td>
		</tr>
		<tr>
			<td>Hoechst 33342</td>
			<td>Molecular Probes</td>
			<td></td>
			<td>Nuclear staining</td>
		</tr>
		<tr>
			<td>Mouse anti-MBP&#160;</td>
			<td>BioLegend</td>
			<td>808402</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse anti-SC123&#160;</td>
			<td>Stem Cells Inc</td>
			<td>AB-123-U-050</td>
			<td></td>
		</tr>
		<tr>
			<td>Normal Donkey Serum</td>
			<td>Merk Millipore</td>
			<td>S30-100</td>
			<td></td>
		</tr>
		<tr>
			<td>Paint brush</td>
			<td>Any suitable</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde (PFA)</td>
			<td>Sigma Aldrich</td>
			<td>150127</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium Phospate Buffer Saline, KPBS (1x)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160; Distilled water</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160; Potassium dihydrogen Phospate (KH2PO4)</td>
			<td>Merk Millipore</td>
			<td>104873</td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160; Potassium phospate dibasic (K2HPO4)</td>
			<td>Sigma Aldrich</td>
			<td>P3786</td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160; Sodium chloride (NaCl)</td>
			<td>Sigma Aldrich</td>
			<td>S3014</td>
			<td></td>
		</tr>
		<tr>
			<td>Rabbit anti-NeuN&#160;</td>
			<td>Abcam</td>
			<td>ab104225</td>
			<td></td>
		</tr>
		<tr>
			<td>Rabbit anti-Olig2&#160;</td>
			<td>Abcam</td>
			<td>ab109186</td>
			<td></td>
		</tr>
		<tr>
			<td>Rabbit anti-TMEM119&#160;</td>
			<td>Abcam</td>
			<td>ab185333</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium azide</td>
			<td>Sigma Aldrich</td>
			<td>S2002-5G</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium citrate</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;&#160; Distilled water</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;&#160; Tri-Sodium Citrate</td>
			<td>Sigma Aldrich</td>
			<td>S1804-500G</td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;&#160;&#160;&#160;&#160;&#160; Tween-20</td>
			<td>Sigma Aldrich</td>
			<td>P1379</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>ThermoFisher Scientific</td>
			<td>327371000&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>EQUIPMENT FOR IMMUNOHISTOCHEMISTRY</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Confocal microscope</td>
			<td>Zeiss</td>
			<td>LSM 780</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope Slides 76 mm x 26 mm</td>
			<td>VWR</td>
			<td>630-1985</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope Coverslips 24 mm x 60 mm</td>
			<td>Marienfeld</td>
			<td>107242</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope Software</td>
			<td>Zeiss</td>
			<td>ZEN Black edition</td>
			<td></td>
		</tr>
		<tr>
			<td>Rubber teat + Glass pipette</td>
			<td>Any suitable</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

organotypic cultures of adult human cortex as an ex vivo model for human stem cell transplantation and validation

Neurodegenerative disorders are common and heterogeneous in terms of their symptoms and cellular affectation, making their study complicated due to the lack of proper animal models that fully mimic human diseases and the poor availability of post-mortem human brain tissue. Adult human nervous tissue culture offers the possibility to study different aspects of neurological disorders. Molecular, cellular, and biochemical mechanisms could be easily addressed in this system, as well as testing and validating drugs or different treatments, such as cell-based therapies. This method combines long-term organotypic cultures of the adult human cortex, obtained from epileptic patients undergoing resective surgery, and ex vivo intracortical transplantation of induced pluripotent stem cell-derived cortical progenitors. This method will allow the study of cell survival, neuronal differentiation, the formation of synaptic inputs and outputs, and the electrophysiological properties of human-derived cells after transplantation into intact adult human cortical tissue. This approach is an important step prior to the development of a 3D human disease modeling platform that will bring basic research closer to the clinical translation of stem cell-based therapies for patients with different neurological disorders and allow the development of new tools for reconstructing damaged neural circuits.

Following the described protocol, hACtx tissue from a patient with temporal lobe epilepsy was collected and processed, as explained above. A few slices were fixed after 24 h in culture to study the starting point of the host tissue. The analysis of different neural cell populations such as neurons (expressing NeuN and Map2, Figure 1A), oligodendrocytes (Olig2 and MBP, Figure 1B), and astrocytes (human-specific GFAP, also named STEM123, Figur...

Watch this Scientific Journal Video about Organotypic Cultures of Adult Human Cortex as an Ex vivo Model for Human Stem Cell Transplantation and Validation at JoVE.com

Organotypic Cultures of Adult Human Cortex as an Ex vivo Model for Human Stem Cell Transplantation and Validation

This protocol describes long-term organotypic cultures of adult human cortex combined with ex vivo intracortical transplantation of induced pluripotent stem cell-derived cortical progenitors, which present a novel methodology to further test stem cell-based therapies for human neurodegenerative disorders.

Organotypic Cultures of Adult Human Cortex as an Ex vivo Model for Human Stem Cell Transplantation and Validation

Neurodegenerative disorders are common and heterogeneous in terms of their symptoms and cellular affectation, making their study complicated due to the ...

organotypic-cultures-adult-human-cortex-as-an-ex-vivo-model-for-human

Research

JoVE Journal

Neuroscience

2.3K Views.  Lund University. This protocol describes long-term organotypic cultures of adult human cortex combined with ex vivo intracortical transplantation of induced pluripotent stem cell-derived cortical progenitors, which present a novel methodology to further test stem cell-based therapies for human neurodegenerative disorders.

Video: Organotypic Cultures of Adult Human Cortex as an Ex vivo Model for Human Stem Cell Transplantation and Validation

Lentivirus-mediated Genetic Manipulation and Visualization of Olfactory Sensory Neurons in vivo

Development of a precise olfactory circuit relies on accurate projection of olfactory sensory neuron (OSN) axons to their synaptic 
targets in the olfactory bulb (OB). The molecular mechanisms of OSN axon growth and targeting are not well understood. Manipulating gene expression and subsequent 
visualizing of single OSN axons and their terminal arbor morphology have thus far been challenging. To study gene function at the single cell level within a specified 
time frame, we developed a lentiviral based technique to manipulate gene expression in OSNs in vivo. Lentiviral particles are delivered to OSNs by microinjection 
into the olfactory epithelium (OE). Expression cassettes are then permanently integrated into the genome of transduced OSNs. Green fluorescent protein expression 
identifies infected OSNs and outlines their entire morphology, including the axon terminal arbor. Due to the short turnaround time between microinjection and 
reporter detection, gene function studies can be focused within a very narrow period of development. With this method, we have detected GFP expression within as 
few as three days and as long as three months following injection. We have achieved both over-expression and shRNA mediated knock-down by lentiviral microinjection. 
This method provides detailed morphologies of OSN cell bodies and axons at the single cell level in vivo, and thus allows characterization of candidate gene function 
during olfactory development.

Lentivirus-mediated Genetic Manipulation and Visualization of Olfactory Sensory Neurons in vivo

We present a lentiviral technique for genetic manipulation and visualization of single olfactory sensory neuron axon and its terminal arborization in vivo.

Development of a precise olfactory circuit relies on accurate projection of olfactory sensory neuron (OSN) axons to their synaptic 
targets in the ...

Methods for Study of Neuronal Morphogenesis: Ex vivo RNAi Electroporation in Embryonic Murine Cerebral Cortex

The cerebral cortex directs higher cognitive functions. This six layered structure is generated in an inside-first, outside-last manner, in which the first born neurons remain closer to the ventricle while the last born neurons migrate past the first born neurons towards the surface of the brain1. In addition to neuronal migration2, a key process for normal cortical function is the regulation of neuronal morphogenesis3. While neuronal morphogenesis can be studied in vitro in primary cultures, there is much to be learned from how these processes are regulated in tissue environments.
We describe techniques to analyze neuronal migration and/or morphogenesis in organotypic slices of the cerebral cortex4,6. A pSilencer modified vector is used which contains both a U6 promoter that drives the double stranded hairpin RNA and a separate expression cassette that encodes GFP protein driven by a CMV promoter7-9. Our approach allows for the rapid assessment of defects in neurite outgrowth upon specific knockdown of candidate genes and has been successfully used in a screen for regulators of neurite outgrowth8. Because only a subset of cells will express the RNAi constructs, the organotypic slices allow for a mosaic analysis of the potential phenotypes. Moreover, because this analysis is done in a near approximation of the in vivo environment, it provides a low cost and rapid alternative to the generation of transgenic or knockout animals for genes of unknown cortical function. Finally, in comparison with in vivo electroporation technology, the success of ex vivo electroporation experiments is not dependant upon proficient surgery skill development and can be performed with a shorter training time and skill.

Methods for Study of Neuronal Morphogenesis: Ex vivo RNAi Electroporation in Embryonic Murine Cerebral Cortex

To conduct a rapid assessment of the function of genes in the development of cerebral cortex, we describe methods involving the ex vivo electroporation of plasmids co-expressing inhibitory RNA (RNAi) and GFP in murine embryonic cortex. This protocol is amenable to the study of various aspects of neurodevelopment such as neurogenesis, neuronal migration and neuronal morphogenesis including dendrite and axon outgrowth.

The cerebral cortex directs higher cognitive functions. This six layered structure is generated in an inside-first, outside-last manner, in which the ...

Ex vivo Culturing of Whole, Developing Drosophila Brains

We describe a method for ex vivo culturing of whole Drosophila brains. This can be used as a counterpoint to chronic genetic manipulations for investigating the cell biology and development of central brain structures by allowing acute pharmacological interventions and live imaging of cellular processes. As an example of the technique, prior work from our lab1 has shown that a previously unrecognized subcellular compartment lies between the axonal and somatodendritic compartments of axons of the Drosophila central brain. The development of this compartment, referred to as the axon initial segment (AIS)2, was shown genetically to depend on the neuron-specific cyclin-dependent kinase, Cdk5. We show here that ex vivo treatment of wild-type Drosophila larval brains with the Cdk5-specific pharmacological inhibitors roscovitine and olomoucine3 causes acute changes in actin organization, and in localization of the cell-surface protein Fasciclin 2, that mimic the changes seen in mutants that lack Cdk5 activity genetically.
A second example of the ex vivo culture technique is provided for remodeling of the connections of embryonic mushroom body (MB) gamma neurons during metamorphosis from larva to adult. The mushroom body is the center of olfactory learning and memory in the fly4, and these gamma neurons prune their axonal and dendritic branches during pupal development and then re-extend branches at a later timepoint to establish the adult innervation pattern5. Pruning of these neurons of the MB has been shown to occur via local degeneration of neurite branches6, by a mechanism that is triggered by ecdysone, a steroid hormone, acting at the ecdysone receptor B17, and that is dependent on the activity of the ubiquitin-proteasome system6. Our method of ex vivo culturing can be used to interrogate further the mechanism of developmental remodeling. We found that in the ex vivo culture setting, gamma neurons of the MB recapitulated the process of developmental pruning with a time course similar to that in vivo. It was essential, however, to wait until 1.5 hours after puparium formation before explanting the tissue in order for the cells to commit irreversibly to metamorphosis; dissection of animals at the onset of pupariation led to little or no metamorphosis in culture. Thus, with appropriate modification, the ex vivo culture approach can be applied to study dynamic as well as steady state aspects of central brain biology.

Ex vivo Culturing of Whole, Developing Drosophila Brains

This article describes a method by which one can mimic in vivo development of the Drosophila mushroom body in an ex vivo culture system.

We describe a method for ex vivo culturing of whole Drosophila brains. This can be used as a counterpoint to chronic genetic manipulations for ...

Ex vivo Live Imaging of Single Cell Divisions in Mouse Neuroepithelium

We developed a system that integrates live imaging of fluorescent markers and culturing slices of embryonic mouse neuroepithelium. We took advantage of existing mouse lines for genetic cell lineage tracing: a tamoxifen-inducible Cre line and a Cre reporter line expressing dsRed upon Cre-mediated recombination. By using a relatively low level of tamoxifen, we were able to induce recombination in a small number of cells, permitting us to follow individual cell divisions. Additionally, we observed the transcriptional response to Sonic Hedgehog (Shh) signaling using an Olig2-eGFP transgenic line 1-3 and we monitored formation of cilia by infecting the cultured slice with virus expressing the cilia marker, Sstr3-GFP 4. In order to image the neuroepithelium, we harvested embryos at E8.5, isolated the neural tube, mounted the neural slice in proper culturing conditions into the imaging chamber and performed time-lapse confocal imaging. Our ex vivo live imaging method enables us to trace single cell divisions to assess the relative timing of primary cilia formation and Shh response in a physiologically relevant manner. This method can be easily adapted using distinct fluorescent markers and provides the field the tools with which to monitor cell behavior in situ and in real time.

Ex vivo Live Imaging of Single Cell Divisions in Mouse Neuroepithelium

Here we develop the tools necessary for ex vivo live imaging to trace single cell divisions in the mouse E8.5 neuroepithelium

We developed a system that integrates live imaging of fluorescent markers and culturing slices of embryonic mouse neuroepithelium. We took advantage of ...

Mouse Hindbrain Ex Vivo Culture to Study Facial Branchiomotor Neuron Migration

Embryonic neurons are born in the ventricular zone of the brain, but subsequently migrate to new destinations to reach appropriate targets. Deciphering the molecular signals that cooperatively guide neuronal migration in the embryonic brain is therefore important to understand how the complex neural networks form which later support postnatal life. Facial branchiomotor (FBM) neurons in the mouse embryo hindbrain migrate from rhombomere (r) 4 caudally to form the paired facial nuclei in the r6-derived region of the hindbrain. Here we provide a detailed protocol for wholemount ex vivo culture of mouse embryo hindbrains suitable to investigate the signaling pathways that regulate FBM migration. In this method, hindbrains of E11.5 mouse embryos are dissected and cultured in an open book preparation on cell culture inserts for 24 hr. During this time, FBM neurons migrate caudally towards r6 and can be exposed to function-blocking antibodies and small molecules in the culture media or heparin beads loaded with recombinant proteins to examine roles for signaling pathways implicated in guiding neuronal migration.

Mouse Hindbrain Ex Vivo Culture to Study Facial Branchiomotor Neuron Migration

Embryonic neurons are born in the ventricular zone of the neural tube, but migrate to reach appropriate targets. Facial branchiomotor (FBM) neurons are a useful model to study neuronal migration. This protocol describes the wholemount ex vivo culture of mouse embryo hindbrains to investigate mechanisms that regulate FBM migration.

Embryonic neurons are born in the ventricular zone of the brain, but subsequently migrate to new destinations to reach appropriate targets. Deciphering ...

Feeder-free Derivation of Neural Crest Progenitor Cells from Human Pluripotent Stem Cells

Human pluripotent stem cells (hPSCs) have great potential for studying human embryonic development, for modeling human diseases in the dish and as a source of transplantable cells for regenerative applications after disease or accidents. Neural crest (NC) cells are the precursors for a large variety of adult somatic cells, such as cells from the peripheral nervous system and glia, melanocytes and mesenchymal cells. They are a valuable source of cells to study aspects of human embryonic development, including cell fate specification and migration. Further differentiation of NC progenitor cells into terminally differentiated cell types offers the possibility to model human diseases in vitro, investigate disease mechanisms and generate cells for regenerative medicine. This article presents the adaptation of a currently available in vitro differentiation protocol for the derivation of NC cells from hPSCs. This new protocol requires 18 days of differentiation, is feeder-free, easily scalable and highly reproducible among human embryonic stem cell (hESC) lines as well as human induced pluripotent stem cell (hiPSC) lines. Both old and new protocols yield NC cells of equal identity.

Neural crest (NC) cells derived from human pluripotent stem cells (hPSC) have great potential for modeling human development and disease and for cell replacement therapies. Here, a feeder-free adaptation of the currently widely used in vitro differentiation protocol for the derivation of NC cells from hPSCs is presented.

Human pluripotent stem cells (hPSCs) have great potential for studying human embryonic development, for modeling human diseases in the dish and as a ...

Organotypic Slice Cultures to Study Oligodendrocyte Dynamics and Myelination

NG2 expressing cells (polydendrocytes, oligodendrocyte precursor cells) are the fourth major glial cell population in the central nervous system. During embryonic and postnatal development they actively proliferate and generate myelinating oligodendrocytes. These cells have commonly been studied in primary dissociated cultures, neuron cocultures, and in fixed tissue. Using newly available transgenic mouse lines slice culture systems can be used to investigate proliferation and differentiation of oligodendrocyte lineage cells in both gray and white matter regions of the forebrain and cerebellum. Slice cultures are prepared from early postnatal mice and are kept in culture for up to 1 month. These slices can be imaged multiple times over the culture period to investigate cellular behavior and interactions. This method allows visualization of NG2 cell division and the steps leading to oligodendrocyte differentiation while enabling detailed analysis of region-dependent NG2 cell and oligodendrocyte functional heterogeneity. This is a powerful technique that can be used to investigate the intrinsic and extrinsic signals influencing these cells over time in a cellular environment that closely resembles that found in vivo.

A technique to study NG2 cells and oligodendrocytes using a slice culture system of the forebrain and cerebellum is described. This method allows examination of the dynamics of proliferation and differentiation of cells within the oligodendrocyte lineage where the extracellular environment can be easily manipulated while maintaining tissue cytoarchitecture.

NG2 expressing cells (polydendrocytes, oligodendrocyte precursor cells) are the fourth major glial cell population in the central nervous system. During ...

Development of a Refined Protocol for Trans-scleral Subretinal Transplantation of Human Retinal Pigment Epithelial Cells into Rat Eyes

Degenerative retinal diseases such as age-related macular degeneration (AMD) are the leading cause of irreversible vision loss worldwide. AMD is characterized by the degeneration of retinal pigment epithelial (RPE) cells, which are a monolayer of cells functionally supporting and anatomically wrapping around the neural retina. Current pharmacological treatments for the non-neovascular AMD (dry AMD) only slow down the disease progression but cannot restore vision, necessitating studies aimed at identifying novel therapeutic strategies. Replacing the degenerative RPE cells with healthy cells holds promise to treat dry AMD in the future. Extensive preclinical studies of stem cell replacement therapies for AMD involve the transplantation of stem cell-derived RPE cells into the subretinal space of animal models, in which the subretinal injection technique is applied. The approach most frequently used in these preclinical animal studies is through the trans-scleral route, which is made difficult by the lack of direct visualization of the needle end and can often result in retinal damage. An alternative approach through the vitreous allows for direct observation of the needle end position, but it carries a high risk of surgical traumas as more eye tissues are disturbed. We have developed a less risky and reproducible modified trans-scleral injection method that uses defined needle angles and depths to successfully and consistently deliver RPE cells into the rat subretinal space and avoid excessive retinal damage. Cells delivered in this manner have been previously demonstrated to be efficacious in the Royal College of Surgeons (RCS) rat for at least 2 months. This technique can be used not only for cell transplantation but also for delivery of small molecules or gene therapies.

Subretinal injection has been widely applied in preclinical studies of stem cell replacement therapy for age-related macular degeneration. In this visualized article, we describe a less risky, reproducible and precisely modified subretinal injection technique via the trans-scleral approach to deliver cells into rat eyes.

Degenerative retinal diseases such as age-related macular degeneration (AMD) are the leading cause of irreversible vision loss worldwide. AMD is ...

Organotypic Hippocampal Slice Cultures As a Model to Study Neuroprotection and Invasiveness of Tumor Cells

In organotypic hippocampal slice cultures (OHSC), the morphological and functional characteristics of both neurons and glial cells are well preserved. This model is suitable for addressing different research questions that involve studies on neuroprotection, electrophysiological experiments on neurons, neuronal networks or tumor invasion. The hippocampal architecture and neuronal activity in multisynaptic circuits are well conserved in OHSC, even though the slicing procedure itself initially lesions and leads to formation of a glial scar. The scar formation alters presumably the mechanical properties and diffusive behavior of small molecules, etc. Slices allow the monitoring of time dependent processes after brain injury without animal surgery, and studies on interactions between various brain-derived cell types, namely astrocytes, microglia and neurons under both physiological and pathological conditions. An ambivalent aspect of this model is the absence of blood flow and immune blood cells. During the progression of the neuronal injury, migrating immune cells from the blood play an important role. As those cells are missing in slices, the intrinsic processes in the culture may be observed without external interference. Moreover, in OHSC the composition of the medium-external environment is precisely controlled. A further advantage of this method is the lower number of sacrificed animals compared to standard preparations. Several OHSC can be obtained from one animal making simultaneous studies with multiple treatments in one animal possible. For these reasons, OHSC are well suited to analyze the effects of new protective therapeutics after tissue damage or during tumor invasion. 
The protocol presented here describes a preparation method of OHSC that allows generating highly reproducible, well preserved slices that can be used for a variety of experimental research, like neuroprotection or tumor invasion studies.

Organotypic hippocampal slice cultures (OHSC) represent an in vitro model that simulates the in vivo situation very well. Here we describe a vibratome-based improved slicing protocol to obtain high quality slices for use in assessing the neuroprotective potential of novel substances or the biological behavior of tumor cells.

In organotypic hippocampal slice cultures (OHSC), the morphological and functional characteristics of both neurons and glial cells are well preserved. ...

Modelling Zika Virus Infection of the Developing Human Brain In Vitro Using Stem Cell Derived Cerebral Organoids

The recent emergence of Zika virus (ZIKV) in susceptible populations has led to an abrupt increase in microcephaly and other neurodevelopmental conditions in newborn infants. While mosquitos are the main route of viral transmission, it has also been shown to spread via sexual contact and vertical mother-to-fetus transmission. In this latter case of transmission, due to the unique viral tropism of ZIKV, the virus is believed to predominantly target the neural progenitor cells (NPCs) of the developing brain.
Here a method for modeling ZIKV infection, and the resulting microcephaly, that occur when human cerebral organoids are exposed to live ZIKV is described. The organoids display high levels of virus within their neural progenitor population, and exhibit severe cell death and microcephaly over time. This three-dimensional cerebral organoid model allows researchers to conduct species-matched experiments to observe and potentially intervene with ZIKV infection of the developing human brain. The model provides improved relevance over standard two-dimensional methods, and contains human-specific cellular architecture and protein expression that are not possible in animal models.

Modelling Zika Virus Infection of the Developing Human Brain In Vitro Using Stem Cell Derived Cerebral Organoids

This protocol describes a technique used to model Zika virus infection of the developing human brain. Using wildtype or engineered stem cell lines, researchers may use this technique to uncover the various mechanisms or treatments that may affect early brain infection and resulting microcephaly in Zika virus-infected embryos.

The recent emergence of Zika virus (ZIKV) in susceptible populations has led to an abrupt increase in microcephaly and other neurodevelopmental conditions ...