We kindly thank the Molecular Imaging Centre and the Flow Cytometry Core Facility at the University of Bergen in Norway. This work was supported by funding from the Norwegian Research Council (Grant number: 229652), Rakel og Otto Kr.Bruuns legat and the China Scholarship Council (project number: 201906220275).

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X., 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=Disease-specific+phenotypes+in+iPSC-derived+neural+stem+cells+with+POLG+mutations.">Disease-specific phenotypes in iPSC-derived neural stem cells with POLG mutations.</a> EMBO Molecular Medicine. 12 (10), 12146 (2020).</li><li>Chen, H., Chan, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondrial+dynamics--fusion,+fission,+movement,+and+mitophagy--in+neurodegenerative+diseases.">Mitochondrial dynamics--fusion, fission, movement, and mitophagy--in neurodegenerative diseases.</a> Human Molecular Genetics. 18, 169-176 (2009).</li><li>Lin, M. T., Beal, M. 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X., 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=Stem+cell+derived+astrocytes+with+POLG+mutations+and+mitochondrial+dysfunction+including+abnormal+NAD++metabolism+is+toxic+for+neurons.">Stem cell derived astrocytes with POLG mutations and mitochondrial dysfunction including abnormal NAD+ metabolism is toxic for neurons.</a> bioRxiv. , (2020).</li><li>Liu, Q., 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+neural+crest+stem+cells+derived+from+human+ESCs+and+induced+pluripotent+stem+cells:+induction,+maintenance,+and+differentiation+into+functional+schwann+cells.">Human neural crest stem cells derived from human ESCs and induced pluripotent stem cells: induction, maintenance, and differentiation into functional schwann cells.</a> Stem Cells Translational Medicine. 1 (4), 266-278 (2012).</li><li>Hong, Y. 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The authors have no conflicts of interest to disclose.

Herein are protocols for generating iPSC&#8722;derived neurons and astrocytes and evaluating multiple aspects of mitochondrial function using flow cytometry. These protocols allow efficient conversion of human iPSCs into both neurons and glial astrocytes and the detailed characterization of mitochondrial function, mostly in living cells. The protocols also provide a co-staining flow cytometry-based strategy for acquiring and analyzing multiple mitochondrial functions, including volume, MMP, and mitochondrial ROS&#160;lev...

Mitochondria are essential organelles present in almost all eukaryotic cells. Mitochondria are responsible for energy supply by producing adenosine triphosphate (ATP) via oxidative phosphorylation and act as metabolic intermediaries for biosynthesis and metabolism. Mitochondria are deeply involved in many other important cellular processes, such as ROS generation, cell death, and intracellular Ca2+ regulation. Mitochondrial dysfunction has been associated with various neurodegenerative diseases, including Parkinson&#39;s disease (PD), Alzheimer&#39;s disease (AD), Huntington&#39;s disease (HD), Friedreich&#39;s ataxia (FRDA), and amyotrophic lateral sclerosis (ALS)1. Increased mitochondrial dysfunction and mtDNA abnormality are also thought to contribute to human aging2,3.
Various types of mitochondrial dysfunction occur in neurodegenerative diseases, and changes in mitochondrial volume, MMP depolarization, production of ROS, and alterations in mtDNA copy number are common4,5,6,7. Therefore, the ability to measure these and other mitochondrial functions is of great importance when studying disease mechanisms and testing potential therapeutic agents. Moreover, in view of the lack of animal models that faithfully replicate human neurodegenerative diseases, establishing suitable in vitro model systems that recapitulate the human disease in brain cells is an important step towards a greater understanding of these diseases and the development of new therapies2,3,8,9.
Human iPSCs can be used to generate various brain cells, including neuronal and non-neuronal cells (i.e., glial cells), and mitochondrial damage associated with neurodegenerative disease has been found in both cell types3,10,11,12,13. Appropriate methods for iPSC differentiation into neural and glial lineages are available14,15,16. These cells provide a unique human/patient platform for in vitro disease modeling and drug screening. Further, as these are derived from patients, iPSC-derived neurons and glial cells provide disease models that reflect what is happening in humans more accurately.
To date, few convenient and reliable methods for measuring multiple mitochondrial functional parameters in iPSCs, particularly living neurons and glial cells, are available. The use of flow cytometry provides the scientist with a powerful tool for measuring biological parameters, including mitochondrial function, in single cells. This protocol provides details for the generation of different types of brain cells, including neural stem cells (NSCs), neurons, and glial astrocytes from iPSCs, as well as novel flow cytometry-based approaches to measure multiple mitochondrial parameters in different cell types, including iPSCs and iPSC-derived neural and glial cells. The protocol also provides a co-staining strategy for using flow cytometry to measure mitochondrial volume, MMP, mitochondrial ROS level, MRC complexes, and TFAM. By incorporating measures of mitochondrial volume or mass, these protocols also allow the measurement of both total level and specific level per mitochondrial unit.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>anti-Oct4</td>
			<td>Abcam</td>
			<td>ab19857, RRID:AB_445175</td>
			<td>Primary Antibody; use as 1:100, 10 &#956;L in 1000 &#956;L staining solution; use Alexa Fluor &#174; 488 goat anti-rabbit IgG&#160; (1:400, Thermo Fisher Scientific, Catalog # A-11008) as secondary antibody.</td>
		</tr>
		<tr>
			<td>anti-SSEA4</td>
			<td>Abcam</td>
			<td>ab16287, RRID:AB_778073</td>
			<td>Primary Antibody; use as 1:100, 10 &#956;L in 1000 &#956;L staining solution; use Alexa Fluor &#174; 594 goat anti-mouse IgG (1:800, Thermo Fisher Scientific, Catalog # A-11005) as secondary antibody.</td>
		</tr>
		<tr>
			<td>anti-Sox2</td>
			<td>Abcam</td>
			<td>ab97959, RRID:AB_2341193</td>
			<td>Primary Antibody; use as 1:100, 10 &#956;L in 1000 &#956;L staining solution; use Alexa Fluor &#174; 488 goat anti-rabbit IgG&#160; (1:400, Thermo Fisher Scientific, Catalog # A-11008) as secondary antibody.</td>
		</tr>
		<tr>
			<td>anti-Pax6</td>
			<td>Abcam</td>
			<td>ab5790, RRID:AB_305110</td>
			<td>Primary Antibody; use as 1:100, 10 &#956;L in 1000 &#956;L staining solution; use Alexa Fluor &#174; 488 goat anti-rabbit IgG&#160; (1:400, Thermo Fisher Scientific, Catalog # A-11008) as secondary antibody.</td>
		</tr>
		<tr>
			<td>anti-Nestin</td>
			<td>Santa Cruz Biotechnology</td>
			<td>sc-23927, RRID:AB_627994</td>
			<td>Primary Antibody; use as 1:50, 20 &#956;L in 1000 &#956;L staining solution; use Alexa Fluor &#174; 594 goat anti-mouse IgG (1:800, Thermo Fisher Scientific, Catalog # A-11005) as secondary antibody.</td>
		</tr>
		<tr>
			<td>anti-GFAP</td>
			<td>Abcam</td>
			<td>ab4674, RRID:AB_304558</td>
			<td>Primary Antibody; use as 1:100, 10 &#956;L in 1000 &#956;L staining solution;&#160; use Alexa Fluor &#174; 594 goat anti-chicken IgG (1:800, Thermo Fisher Scientific, Catalog # A-11042) as secondary antibody.</td>
		</tr>
		<tr>
			<td>anti-S100&#946;&#160; conjugated with Alexa Fluor 488</td>
			<td>Abcam</td>
			<td>ab196442, RRID:AB_2722596</td>
			<td>Primary Antibody; use as 1:400, 2.5 &#956;L in 1000 &#956;L staining solution;</td>
		</tr>
		<tr>
			<td>anti-TH</td>
			<td>Abcam</td>
			<td>ab75875, RRID:AB_1310786</td>
			<td>Primary Antibody; use as 1:100, 10 &#956;L in 1000 &#956;L staining solution; use Alexa Fluor &#174; 488 goat anti-rabbit IgG&#160; (1:400, Thermo Fisher Scientific, Catalog # A-11008) as secondary antibody.</td>
		</tr>
		<tr>
			<td>anti-Tuj 1</td>
			<td>Abcam</td>
			<td>ab78078, RRID:AB_2256751</td>
			<td>Primary Antibody; use as 1:1000, 1 &#956;L in 1000 &#956;L staining solution; use Alexa Fluor &#174; 594 goat anti-mouse IgG (1:800, Thermo Fisher Scientific, Catalog # A-11005) as secondary antibody.</td>
		</tr>
		<tr>
			<td>anti-Synaptophysin</td>
			<td>Abcam</td>
			<td>ab32127, RRID:AB_2286949</td>
			<td>Primary Antibody; use as 1:100, 10 &#956;L in 1000 &#956;L staining solution; use Alexa Fluor &#174; 488 goat anti-rabbit IgG&#160; (1:400, Thermo Fisher Scientific, Catalog # A-11008) as secondary antibody.</td>
		</tr>
		<tr>
			<td>anti-PSD-95</td>
			<td>Abcam</td>
			<td>ab2723, RRID:AB_303248</td>
			<td>Primary Antibody; use as 1:100, 10 &#956;L in 1000 &#956;L staining solution;&#160; use Alexa Fluor &#174; 594 goat anti-chicken IgG (1:800, Thermo Fisher Scientific, Catalog # A-11042) as secondary antibody.</td>
		</tr>
		<tr>
			<td>anti-TFAM conjugated with Alexa Fluor 488</td>
			<td>Abcam</td>
			<td>ab198308</td>
			<td>Primary Antibody; use as 1:400, 2.5 &#956;L in 1000 &#956;L staining solution; use mouse monoclonal IgG2b&#160; Alexa Fluor&#174; 488 as an isotype control.</td>
		</tr>
		<tr>
			<td>anti-TOMM20 conjugated with Alexa Fluor 488</td>
			<td>Santa Cruz Biotechnology</td>
			<td>Cat# sc-17764 RRID:AB_628381</td>
			<td>Primary Antibody; use as 1:400, 2.5 &#956;L in 1000 &#956;L staining solution; use mouse monoclonal IgG2a&#160; Alexa Fluor&#174; 488 as an isotype control.</td>
		</tr>
		<tr>
			<td>anti-NDUFB10</td>
			<td>Abcam</td>
			<td>ab196019</td>
			<td>Primary Antibody; use as 1:1000, 1 &#956;L in 1000 &#956;L staining solution; use Alexa Fluor &#174; 488 goat anti-rabbit IgG&#160; (1:400, Thermo Fisher Scientific, Catalog # A-11008) as secondary antibody; use rabbit monoclonal IgG as an isotype control.</td>
		</tr>
		<tr>
			<td>anti-SDHA</td>
			<td>Abcam</td>
			<td>ab137040</td>
			<td>Primary Antibody; use as 1:1000, 1 &#956;L in 1000 &#956;L staining solution;&#160; use Alexa Fluor &#174; 488 goat anti-rabbit IgG&#160; (1:400, Thermo Fisher Scientific, Catalog # A-11008) as secondary antibody; use rabbit monoclonal IgG as an isotype control.</td>
		</tr>
		<tr>
			<td>anti-COX IV</td>
			<td>Abcam</td>
			<td>ab14744, RRID:AB_301443</td>
			<td>Primary Antibody; use as 1:1000, 1 &#956;L in 1000 &#956;L staining solution; use&#160; Alexa Fluor &#174; 488 goat anti-mouse IgG&#160; (1:400, Thermo Fisher Scientific, Catalog # A-11001) as secondary antibody; use mouse monoclonal IgG as an isotype control.</td>
		</tr>
		<tr>
			<td>Activin A</td>
			<td>PeproTech</td>
			<td>120-14E</td>
			<td>Astrocyte differentiation medium ingredient</td>
		</tr>
		<tr>
			<td>ABM Basal Medium</td>
			<td>Lonza</td>
			<td>CC-3187</td>
			<td>Basal medium for astrocyte culture</td>
		</tr>
		<tr>
			<td>AGM SingleQuots Supplement Pack</td>
			<td>Lonza</td>
			<td>CC-4123</td>
			<td>Supplement for astrocyte culture</td>
		</tr>
		<tr>
			<td>Antibiotic-Antimycotic</td>
			<td>Thermo Fisher Scientific</td>
			<td>15240062</td>
			<td>CDM ingredient</td>
		</tr>
		<tr>
			<td>Advanced DMEM/F-12</td>
			<td>Thermo Fisher Scientific</td>
			<td>12634010</td>
			<td>Basal medium for dilute Geltrex</td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin</td>
			<td>Europa Bioproducts</td>
			<td>EQBAH62-1000</td>
			<td>Blocking agent to prevent non-specific binding of antibodies in immunostaining assays and CDM ingredient</td>
		</tr>
		<tr>
			<td>BDNF</td>
			<td>PeproTech</td>
			<td>450-02</td>
			<td>DA neurons medium ingredient</td>
		</tr>
		<tr>
			<td>B-27 Supplement</td>
			<td>Thermo Fisher Scientific</td>
			<td>17504044</td>
			<td>Astrocyte differentiation medium ingredient</td>
		</tr>
		<tr>
			<td>BD Accuri C6 Plus Flow Cytometer</td>
			<td>BD Biosciences, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Chemically Defined Lipid Concentrate</td>
			<td>Thermo Fisher Scientific</td>
			<td>11905031</td>
			<td>CDM ingredient</td>
		</tr>
		<tr>
			<td>Collagenase IV</td>
			<td>Thermo Fisher Scientific</td>
			<td>17104019</td>
			<td>Reagent for gentle dissociation of human iPSCs</td>
		</tr>
		<tr>
			<td>CCD Microscope Camera Leica DFC3000 G</td>
			<td>Leica Microsystems, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Corning non-treated culture dishes</td>
			<td>Sigma-Aldrich</td>
			<td>CLS430589</td>
			<td>Suspension culture</td>
		</tr>
		<tr>
			<td>DPBS</td>
			<td>Thermo Fisher Scientific</td>
			<td>14190250</td>
			<td>Used for a variety of cell culture wash</td>
		</tr>
		<tr>
			<td>DMEM/F-12, GlutaMAX supplement</td>
			<td>Thermo Fisher Scientific</td>
			<td>10565018</td>
			<td>Astrocyte differentiation basal Medium</td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Thermo Fisher Scientific</td>
			<td>15575020</td>
			<td>Reagent for gentle dissociation of human iPSCs</td>
		</tr>
		<tr>
			<td>Essential 8 Basal Medium</td>
			<td>Thermo Fisher Scientific</td>
			<td>A1516901</td>
			<td>Basal medium for iPSC culture</td>
		</tr>
		<tr>
			<td>Essential 8 Supplement (50X)</td>
			<td>Thermo Fisher Scientific</td>
			<td>A1517101</td>
			<td>Supplement for iPSC culture</td>
		</tr>
		<tr>
			<td>EGF Recombinant Human Protein</td>
			<td>Thermo Fisher Scientific</td>
			<td>PHG0314</td>
			<td>Supplement for NSC culture</td>
		</tr>
		<tr>
			<td>FGF-basic (AA 10&#8211;155) Recombinant Human Protein</td>
			<td>Thermo Fisher Scientific</td>
			<td>PHG0024</td>
			<td>Supplement for NSC culture</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Sigma-Aldrich</td>
			<td>12103C</td>
			<td>Medium ingredient</td>
		</tr>
		<tr>
			<td>FGF-basic</td>
			<td>PeproTech</td>
			<td>100-18B</td>
			<td>Astrocyte differentiation medium ingredient</td>
		</tr>
		<tr>
			<td>FCCP</td>
			<td>Abcam</td>
			<td>ab120081</td>
			<td>Eliminates mitochondrial membrane potential and TMRE staining</td>
		</tr>
		<tr>
			<td>Fluid aspiration system BVC control</td>
			<td>Vacuubrand, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Formaldehyde (PFA) 16%</td>
			<td>Thermo Fisher Scientific</td>
			<td>28908</td>
			<td>Cell fixation</td>
		</tr>
		<tr>
			<td>Geltrex</td>
			<td>Thermo Fisher Scientific</td>
			<td>A1413302</td>
			<td>Used for attachment and maintenance of human iPSCs</td>
		</tr>
		<tr>
			<td>GlutaMAX Supplement</td>
			<td>Thermo Fisher Scientific</td>
			<td>35050061</td>
			<td>Supplement for NSC culture</td>
		</tr>
		<tr>
			<td>GDNF</td>
			<td>Peprotech</td>
			<td>450-10</td>
			<td>DA neurons medium ingredient</td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td>Sigma-Aldrich</td>
			<td>G8898</td>
			<td>Used for blocking buffer</td>
		</tr>
		<tr>
			<td>Ham&#39;s F-12 Nutrient Mix</td>
			<td>Thermo Fisher Scientific</td>
			<td>31765027</td>
			<td>Basal medium for CDM</td>
		</tr>
		<tr>
			<td>Heregulin beta-1 human</td>
			<td>Sigma-Aldrich</td>
			<td>SRP3055</td>
			<td>Astrocyte differentiation medium ingredient</td>
		</tr>
		<tr>
			<td>Hoechst 33342</td>
			<td>Thermo Fisher Scientific</td>
			<td>H1399</td>
			<td>Stain the nuclei for confocal image</td>
		</tr>
		<tr>
			<td>Heracell 150i CO2 Incubators</td>
			<td>Fisher Scientific, USA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>IMDM</td>
			<td>Thermo Fisher Scientific</td>
			<td>21980032</td>
			<td>Basal medium for CDM</td>
		</tr>
		<tr>
			<td>Insulin</td>
			<td>Roche</td>
			<td>1376497</td>
			<td>CDM ingredient</td>
		</tr>
		<tr>
			<td>InSolution AMPK Inhibitor</td>
			<td>Sigma-Aldrich</td>
			<td>171261</td>
			<td>Neural induction medium ingredient</td>
		</tr>
		<tr>
			<td>Insulin-like Growth Factor-I human</td>
			<td>Sigma-Aldrich</td>
			<td>I3769</td>
			<td>Astrocyte differentiation medium ingredient</td>
		</tr>
		<tr>
			<td>KnockOut DMEM/F-12 medium</td>
			<td>Thermo Fisher Scientific</td>
			<td>12660012</td>
			<td>Basal medium for NSC culture</td>
		</tr>
		<tr>
			<td>Laminin</td>
			<td>Sigma-Aldrich</td>
			<td>L2020</td>
			<td>Promotes attachment and growth of neural cells in vitro</td>
		</tr>
		<tr>
			<td>Leica TCS SP8 STED confocal microscope</td>
			<td>Leica Microsystems, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Monothioglycerol</td>
			<td>Sigma-Aldrich</td>
			<td>M6145</td>
			<td>CDM ingredient</td>
		</tr>
		<tr>
			<td>MitoTracker Green FM</td>
			<td>Thermo Fisher Scientific</td>
			<td>M7514</td>
			<td>Used for mitochondrial volume indicator</td>
		</tr>
		<tr>
			<td>MitoSox Red</td>
			<td>Thermo Fisher Scientific</td>
			<td>M36008</td>
			<td>Used for mitochondrial ROS indicator</td>
		</tr>
		<tr>
			<td>N-Acetyl-L-cysteine</td>
			<td>Sigma-Aldrich</td>
			<td>A7250</td>
			<td>Neural induction medium ingredient</td>
		</tr>
		<tr>
			<td>N-2 Supplement</td>
			<td>Thermo Fisher Scientific</td>
			<td>17502048</td>
			<td>Astrocyte differentiation medium ingredient</td>
		</tr>
		<tr>
			<td>Normal goat serum</td>
			<td>Thermo Fisher Scientific</td>
			<td>PCN5000</td>
			<td>Used for blocking buffer</td>
		</tr>
		<tr>
			<td>Orbital shakers - SSM1</td>
			<td>Stuart Equipment, UK</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Poly-L-ornithine solution</td>
			<td>Sigma-Aldrich</td>
			<td>P4957</td>
			<td>Promotes attachment and growth of neural cells in vitro</td>
		</tr>
		<tr>
			<td>Poly-D-lysine hydrobromide</td>
			<td>Sigma-Aldrich</td>
			<td>P7405</td>
			<td>Promotes attachment and growth of neural cells in vitro</td>
		</tr>
		<tr>
			<td>Purmorphamine</td>
			<td>STEMCELL Technologies</td>
			<td>72204</td>
			<td>Promotes DA neuron differentiation</td>
		</tr>
		<tr>
			<td>ProLong Gold Antifade Mountant</td>
			<td>Thermo Fisher Scientific</td>
			<td>P36930</td>
			<td>Mounting the coverslip for confocal image</td>
		</tr>
		<tr>
			<td>PBS 1x</td>
			<td>Thermo Fisher Scientific</td>
			<td>18912014</td>
			<td>Used for a variety of wash</td>
		</tr>
		<tr>
			<td>Recombinant Human/Mouse FGF-8b Protein</td>
			<td>R&#38;D Systems</td>
			<td>423-F8-025/CF</td>
			<td>Promotes DA neuron differentiation</td>
		</tr>
		<tr>
			<td>SB 431542</td>
			<td>Tocris Bioscience</td>
			<td>TB1614-GMP</td>
			<td>Neural Induction Medium ingredient</td>
		</tr>
		<tr>
			<td>StemPro Neural Supplement</td>
			<td>Thermo Fisher Scientific</td>
			<td>A10508-01</td>
			<td>Supplement for NSCs culture</td>
		</tr>
		<tr>
			<td>TrypLE Express Enzyme</td>
			<td>Thermo Fisher Scientific</td>
			<td>12604013</td>
			<td>Cell dissociation reagent</td>
		</tr>
		<tr>
			<td>Transferrin</td>
			<td>Roche</td>
			<td>652202</td>
			<td>CDM ingredient</td>
		</tr>
		<tr>
			<td>TRITON X-100</td>
			<td>VWR International</td>
			<td>9002-93-1</td>
			<td>Used for cells permeabilization in immunostaining assays</td>
		</tr>
		<tr>
			<td>TMRE</td>
			<td>Abcam</td>
			<td>ab113852</td>
			<td>Used for mitochondrial membrane potential staining</td>
		</tr>
		<tr>
			<td>Water Bath Jb Academy Basic Jba5 JBA5 Grant Instruments</td>
			<td>Grant Instruments, USA</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

flow cytometric analysis of multiple mitochondrial parameters in human induced pluripotent stem cells and their neural and glial derivatives

Mitochondria are important in the pathophysiology of many neurodegenerative diseases. Changes in mitochondrial volume, mitochondrial membrane potential (MMP), mitochondrial production of reactive oxygen species (ROS), and mitochondrial DNA (mtDNA) copy number are often features of these processes. This report details a novel flow cytometry-based approach to measure multiple mitochondrial parameters in different cell types, including human induced pluripotent stem cells (iPSCs) and iPSC-derived neural and glial cells. This flow-based strategy uses live cells to measure mitochondrial volume, MMP, and ROS levels, as well as fixed cells to estimate components of the mitochondrial respiratory chain (MRC) and mtDNA-associated proteins such as mitochondrial transcription factor A (TFAM). 
By co-staining with fluorescent reporters, including MitoTracker Green (MTG), tetramethylrhodamine ethyl ester (TMRE), and MitoSox Red, changes in mitochondrial volume, MMP, and mitochondrial ROS can be quantified and related to mitochondrial content. Double staining with antibodies against MRC complex subunits and translocase of outer mitochondrial membrane 20 (TOMM20) permits the assessment of MRC subunit expression. As the amount of TFAM is proportional to mtDNA copy number, the measurement of TFAM per TOMM20 gives an indirect measurement of mtDNA per mitochondrial volume. The entire protocol can be carried out within 2-3 h. Importantly, these protocols allow the measurement of mitochondrial parameters, both at the total level and the specific level per mitochondrial volume, using flow cytometry.

A schematic description of the differentiation method and flow cytometric strategies is shown in Figure 3. Human iPSCs are differentiated into neural rosettes and then lifted into suspension culture for differentiation into neural spheres. Neural spheres are further differentiated and matured into DA neurons. Neural spheres are dissociated into single cells to generate glial astrocytes, replated in monolayers as NSCs, and then differentiated into astrocytes. This protocol provides the strate...

Watch this Scientific Journal Video about Flow Cytometric Analysis of Multiple Mitochondrial Parameters in Human Induced Pluripotent Stem Cells and Their Neural and Glial Derivatives at JoVE.com

Flow Cytometric Analysis of Multiple Mitochondrial Parameters in Human Induced Pluripotent Stem Cells and Their Neural and Glial Derivatives

This study reports a novel approach to measure multiple mitochondrial functional parameters based on flow cytometry and double staining with two fluorescent reporters or antibodies to detect changes in mitochondrial volume, mitochondrial membrane potential, reactive oxygen species level, mitochondrial respiratory chain composition, and mitochondrial DNA.

Mitochondria are important in the pathophysiology of many neurodegenerative diseases. Changes in mitochondrial volume, mitochondrial membrane potential ...

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Research

JoVE Journal

Neuroscience

3.9K Views.  University of Bergen. This study reports a novel approach to measure multiple mitochondrial functional parameters based on flow cytometry and double staining with two fluorescent reporters or antibodies to detect changes in mitochondrial volume, mitochondrial membrane potential, reactive oxygen species level, mitochondrial respiratory chain composition, and mitochondrial DNA.

Video: Flow Cytometric Analysis of Multiple Mitochondrial Parameters in Human Induced Pluripotent Stem Cells and Their Neural and Glial Derivatives

Time-lapse Live Imaging of Clonally Related Neural Progenitor Cells in the Developing Zebrafish Forebrain

Precise patterns of division, migration and differentiation of neural progenitor cells are crucial for proper brain development and function1,2. To understand the behavior of neural progenitor cells in the complex in vivo environment, time-lapse live imaging of neural progenitor cells in an intact brain is critically required. In this video, we exploit the unique features of zebrafish embryos to visualize the development of forebrain neural progenitor cells in vivo. We use electroporation to genetically and sparsely label individual neural progenitor cells. Briefly, DNA constructs coding for fluorescent markers were injected into the forebrain ventricle of 22 hours post fertilization (hpf) zebrafish embryos and electric pulses were delivered immediately. Six hours later, the electroporated zebrafish embryos were mounted with low melting point agarose in glass bottom culture dishes. Fluorescently labeled neural progenitor cells were then imaged for 36hours with fixed intervals under a confocal microscope using water dipping objective lens. The present method provides a way to gain insights into the in vivo development of forebrain neural progenitor cells and can be applied to other parts of the central nervous system of the zebrafish embryo.

The present video demonstrates a method which takes advantage of the combination of electroporation and confocal microscopy to perform live imaging on individual neural progenitor cells in the developing zebrafish forebrain. In vivo analysis of the development of forebrain neural progenitor cells at a clonal level can be achieved in this way.

Precise patterns of division, migration and differentiation of neural progenitor cells are crucial for proper brain development and function1,2. To ...

Efficient Derivation of Human Neuronal Progenitors and Neurons from Pluripotent Human Embryonic Stem Cells with Small Molecule Induction

There is a large unfulfilled need for a clinically-suitable human neuronal cell source for repair or regeneration of the damaged central nervous system (CNS) structure and circuitry in today's healthcare industry. Cell-based therapies hold great promise to restore the lost nerve tissue and function for CNS disorders. However, cell therapies based on CNS-derived neural stem cells have encountered supply restriction and difficulty to use in the clinical setting due to their limited expansion ability in culture and failing plasticity after extensive passaging1-3. Despite some beneficial outcomes, the CNS-derived human neural stem cells (hNSCs) appear to exert their therapeutic effects primarily by their non-neuronal progenies through producing trophic and neuroprotective molecules to rescue the endogenous cells1-3. Alternatively, pluripotent human embryonic stem cells (hESCs) proffer cures for a wide range of neurological disorders by supplying the diversity of human neuronal cell types in the developing CNS for regeneration1,4-7. However, how to channel the wide differentiation potential of pluripotent hESCs efficiently and predictably to a desired phenotype has been a major challenge for both developmental study and clinical translation. Conventional approaches rely on multi-lineage inclination of pluripotent cells through spontaneous germ layer differentiation, resulting in inefficient and uncontrollable lineage-commitment that is often followed by phenotypic heterogeneity and instability, hence, a high risk of tumorigenicity7-10. In addition, undefined foreign/animal biological supplements and/or feeders that have typically been used for the isolation, expansion, and differentiation of hESCs may make direct use of such cell-specialized grafts in patients problematic11-13. To overcome these obstacles, we have resolved the elements of a defined culture system necessary and sufficient for sustaining the epiblast pluripotence of hESCs, serving as a platform for de novo derivation of clinically-suitable hESCs and effectively directing such hESCs uniformly towards clinically-relevant lineages by small molecules14 (please see a schematic in Fig. 1). Retinoic acid (RA) does not induce neuronal differentiation of undifferentiated hESCs maintained on feeders1, 14. And unlike mouse ESCs, treating hESC-differentiated embryoid bodies (EBs) only slightly increases the low yield of neurons1, 14, 15. However, after screening a variety of small molecules and growth factors, we found that such defined conditions rendered retinoic acid (RA) sufficient to induce the specification of neuroectoderm direct from pluripotent hESCs that further progressed to neuroblasts that generated human neuronal progenitors and neurons in the developing CNS with high efficiency (Fig. 2). We defined conditions for induction of neuroblasts direct from pluripotent hESCs without an intervening multi-lineage embryoid body stage, enabling well-controlled efficient derivation of a large supply of human neuronal cells across the spectrum of developmental stages for cell-based therapeutics.

We have established a protocol for induction of neuroblasts direct from pluripotent human embryonic stem cells maintained under defined conditions with small molecules, which enables derivation of a large supply of human neuronal progenitors and neuronal cell types in the developing CNS for neural repair.

There is a large unfulfilled need for a clinically-suitable human neuronal cell source for repair or regeneration of the damaged central nervous system ...

A cGMP-applicable Expansion Method for Aggregates of Human Neural Stem and Progenitor Cells Derived From Pluripotent Stem Cells or Fetal Brain Tissue

A cell expansion technique to amass large numbers of cells from a single specimen for research experiments and clinical trials would greatly benefit the stem cell community. Many current expansion methods are laborious and costly, and those involving complete dissociation may cause several stem and progenitor cell types to undergo differentiation or early senescence. To overcome these problems, we have developed an automated mechanical passaging method referred to as &#8220;chopping&#8221; that is simple and inexpensive. This technique avoids chemical or enzymatic dissociation into single cells and instead allows for the large-scale expansion of suspended, spheroid cultures that maintain constant cell/cell contact. The chopping method has primarily been used for fetal brain-derived neural progenitor cells or neurospheres, and has recently been published for use with neural stem cells derived from embryonic and induced pluripotent stem cells. The procedure involves seeding neurospheres onto a tissue culture Petri dish and subsequently passing a sharp, sterile blade through the cells effectively automating the tedious process of manually mechanically dissociating each sphere. Suspending cells in culture provides a favorable surface area-to-volume ratio; as over 500,000 cells can be grown within a single neurosphere of less than 0.5 mm in diameter. In one T175 flask, over 50 million cells can grow in suspension cultures compared to only 15 million in adherent cultures. Importantly, the chopping procedure has been used under current good manufacturing practice (cGMP), permitting mass quantity production of clinical-grade cell products.

This protocol describes a novel mechanical chopping method that allows the expansion of spherical neural stem and progenitor cell aggregates without dissociation to a single cell suspension.&#160; Maintaining cell/cell contact allows rapid and stable growth for over 40 passages.

A cell expansion technique to amass large numbers of cells from a single specimen for research experiments and clinical trials would greatly benefit the ...

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 ...

Directed Dopaminergic Neuron Differentiation from Human Pluripotent Stem Cells

Dopaminergic (DA) neurons in the substantia nigra pars compacta (also known as A9 DA neurons) are the specific cell type that is lost in Parkinson&#8217;s disease (PD). There is great interest in deriving A9 DA neurons from human pluripotent stem cells (hPSCs) for regenerative cell replacement therapy for PD. During neural development, A9 DA neurons originate from the floor plate (FP) precursors located at the ventral midline of the central nervous system. Here, we optimized the culture conditions for the stepwise differentiation of hPSCs to A9 DA neurons, which mimics embryonic DA neuron development. In our protocol, we first describe the efficient generation of FP precursor cells from hPSCs using a small molecule method, and then convert the FP cells to A9 DA neurons, which could be maintained in vitro for several months. This efficient, repeatable and controllable protocol works well in human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) from normal persons and PD patients, in which one could derive A9 DA neurons to perform in vitro disease modeling and drug screening and in vivo cell transplantation therapy for PD.

We, based on knowledge from developmental biology and published research, developed an optimized protocol to efficiently generate A9 midbrain dopaminergic neurons from both human embryonic stem cells and human induced pluripotent stem cells, which would be useful for disease modeling and cell replacement therapy for Parkinson&#8217;s disease.

Dopaminergic (DA) neurons in the substantia nigra pars compacta  (also known as A9 DA neurons) are the specific cell type that is lost in ...

Derivation of Adult Human Fibroblasts and their Direct Conversion into Expandable Neural Progenitor Cells

Generation of&#160;induced pluripotent stem cell (iPSCs) from adult skin fibroblasts and subsequent differentiation into somatic cells provides fascinating prospects for the derivation of autologous transplants that circumvent histocompatibility barriers. However, progression through a pluripotent state and subsequent complete differentiation into desired lineages remains a roadblock for the clinical translation of iPSC technology because of the associated neoplastic potential and genomic instability. Recently, we and others showed that somatic cells cannot only be converted into iPSCs but also into different types of multipotent somatic stem cells by using defined factors, thereby circumventing progression through the pluripotent state. In particular, the direct conversion of human fibroblasts into induced neural progenitor cells (iNPCs) heralds the possibility of a novel autologous cell source for various applications such as cell replacement, disease modeling and drug screening. Here, we describe the isolation of adult human primary fibroblasts by skin biopsy and their efficient direct conversion into iNPCs by timely restricted expression of Oct4, Sox2, Klf4, as well as c-Myc. Sox2-positive neuroepithelial colonies appear after 17 days of induction and iNPC lines can be established efficiently by monoclonal isolation and expansion. Precise adjustment of viral multiplicity of infection and supplementation of leukemia inhibitory factor during the induction phase represent critical factors to achieve conversion efficiencies of up to 0.2%. Thus far, patient-specific iNPC lines could be expanded for more than 12 passages and uniformly display morphological and molecular features of neural stem/progenitor cells, such as the expression of Nestin and Sox2. The iNPC lines can be differentiated into neurons and astrocytes as judged by staining against TUJ1 and GFAP, respectively. In conclusion, we report a robust protocol for the derivation and direct conversion of human fibroblasts into stably expandable neural progenitor cells that might provide a cellular source for biomedical applications such as autologous neural cell replacement and disease modeling.

Generation of induced pluripotent stem cells provides fascinating prospects for the derivation of autologous transplants. However, progression through a pluripotent state and laborious re-differentiation still hinders clinical translation. Here we describe the derivation of adult human fibroblasts and their direct conversion into induced neural progenitor cells and the subsequent differentiation into neural lineages.

Generation of&#160;induced pluripotent stem cell (iPSCs) from adult skin fibroblasts and subsequent differentiation into somatic cells provides ...

Conversion of Human Induced Pluripotent Stem Cells (iPSCs) into Functional Spinal and Cranial Motor Neurons Using PiggyBac Vectors

We describe here a method to obtain functional spinal and cranial motor neurons from human induced pluripotent stem cells (iPSCs). Direct conversion into motor neuron is obtained by ectopic expression of alternative modules of transcription factors, namely Ngn2, Isl1 and Lhx3 (NIL) or Ngn2, Isl1 and Phox2a (NIP). NIL and NIP specify, respectively, spinal and cranial motor neuron identity. Our protocol starts with the generation of modified iPSC lines in which NIL or NIP are stably integrated in the genome via a piggyBac transposon vector. Expression of the transgenes is then induced by doxycycline and leads, in 5 days, to the conversion of iPSCs into MN progenitors. Subsequent maturation, for 7 days, leads to homogeneous populations of spinal or cranial MNs. Our method holds several advantages over previous protocols: it is extremely rapid and simplified; it does not require viral infection or further MN isolation; it allows generating different MN subpopulations (spinal and cranial) with a remarkable degree of maturation, as demonstrated by the ability to fire trains of action potentials. Moreover, a large number of motor neurons can be obtained without purification from mixed populations. iPSC-derived spinal and cranial motor neurons can be used for in vitro modeling of Amyotrophic Lateral Sclerosis and other neurodegenerative diseases of the motor neuron. Homogeneous motor neuron populations might represent an important resource for cell type specific drug screenings.

Conversion of Human Induced Pluripotent Stem Cells iPSCs into Functional Spinal and Cranial Motor Neurons Using PiggyBac Vectors

This protocol allows rapid and efficient conversion of induced pluripotent stem cells into motor neurons with a spinal or cranial identity, by ectopic expression of transcription factors from inducible piggyBac vectors.

We describe here a method to obtain functional spinal and cranial motor neurons from human induced pluripotent stem cells (iPSCs). Direct conversion into ...

Analyzing Mitochondrial Transport and Morphology in Human Induced Pluripotent Stem Cell-Derived Neurons in Hereditary Spastic Paraplegia

Neurons have intense demands for high energy in order to support their functions. Impaired mitochondrial transport along axons has been observed in human neurons, which may contribute to neurodegeneration in various disease states. Although it is challenging to examine mitochondrial dynamics in live human nerves, such paradigms are critical for studying the role of mitochondria in neurodegeneration. Described here is a protocol for analyzing mitochondrial transport and mitochondrial morphology in forebrain neuron axons derived from human induced pluripotent stem cells (iPSCs). The iPSCs are differentiated into telencephalic glutamatergic neurons using well-established methods. Mitochondria of the neurons are stained with MitoTracker CMXRos, and mitochondrial movement within the axons are captured using a live-cell imaging microscope equipped with an incubator for cell culture. Time-lapse images are analyzed using software with &#34;MultiKymograph&#34;, &#34;Bioformat importer&#34;, and &#34;Macros&#34; plugins. Kymographs of mitochondrial transport are generated, and average mitochondrial velocity in the anterograde and retrograde directions is read from the kymograph. Regarding mitochondrial morphology analysis, mitochondrial length, area, and aspect ratio are obtained using the ImageJ. In summary, this protocol allows characterization of mitochondrial trafficking along axons and analysis of their morphology to facilitate studies of neurodegenerative diseases.

Impaired mitochondrial transport and morphology are involved in various neurodegenerative diseases. The presented protocol uses induced pluripotent stem cell-derived forebrain neurons to assess mitochondrial transport and morphology in hereditary spastic paraplegia. This protocol allows characterization of mitochondrial trafficking along axons and analysis of their morphology, which will facilitate the study of neurodegenerative disease.

Neurons have intense demands for high energy in order to support their functions. Impaired mitochondrial transport along axons has been observed in human ...

Derivation, Expansion, Cryopreservation and Characterization of Brain Microvascular Endothelial Cells from Human Induced Pluripotent Stem Cells

Brain microvascular endothelial cells (BMECs) can be differentiated from human induced pluripotent stem cells (iPSCs) to develop ex vivo cellular models for studying blood-brain barrier (BBB) function. This modified protocol provides detailed steps to derive, expand, and cryopreserve BMECs from human iPSCs using a different donor and reagents than those reported in previous protocols. iPSCs are treated with essential 6 medium for 4 days, followed by 2 days of human endothelial serum-free culture medium supplemented with basic fibroblast growth factor, retinoic acid, and B27 supplement. At day 6, cells are sub-cultured onto a collagen/fibronectin matrix for 2 days. Immunocytochemistry is performed at day 8 for BMEC marker analysis using CLDN5, OCLN, TJP1, PECAM1, and SLC2A1. Western blotting is performed to confirm BMEC marker expression, and absence of SOX17, an endodermal marker. Angiogenic potential is demonstrated with a sprouting assay. Trans-endothelial electrical resistance (TEER) is measured using chopstick electrodes and voltohmmeter starting at day 7. Efflux transporter activity for ATP binding cassette subfamily B member 1 and ATP binding cassette subfamily C member 1 is measured using a multi-plate reader at day 8. Successful derivation of BMECs is confirmed by the presence of relevant cell markers, low levels of SOX17, angiogenic potential, transporter activity, and TEER values ~2000 &#937; x cm2. BMECs are expanded until day 10 before passaging onto freshly coated collagen/fibronectin plates or cryopreserved. This protocol demonstrates that iPSC-derived BMECs can be expanded and passaged at least once. However, lower TEER values and poorer localization of BMEC markers was observed after cryopreservation. BMECs can be utilized in co-culture experiments with other cell types (neurons, glia, pericytes), in three-dimensional brain models (organ-chip and hydrogel), for vascularization of brain organoids, and for studying BBB dysfunction in neuropsychiatric disorders.

This protocol details an adapted method to derive, expand, and cryopreserve brain microvascular endothelial cells obtained by differentiating human induced pluripotent stem cells, and to study blood brain barrier properties in an ex vivo model.

Brain microvascular endothelial cells (BMECs) can be differentiated from human induced pluripotent stem cells (iPSCs) to develop ex vivo cellular models ...

Human Microglia-like Cells: Differentiation from Induced Pluripotent Stem Cells and In Vitro Live-cell Phagocytosis Assay using Human Synaptosomes

Microglia are the resident immune cells of myeloid origin that maintain homeostasis in the brain microenvironment and have become a key player in multiple neurological diseases. Studying human microglia in health and disease represents a challenge due to the extremely limited supply of human cells. Induced pluripotent stem cells (iPSCs) derived from human individuals can be used to circumvent this barrier. Here, it is demonstrated how to differentiate human iPSCs into microglia-like cells (iMGs) for in vitro experimentation. These iMGs exhibit the expected and physiological properties of microglia, including microglia-like morphology, expression of proper markers, and active phagocytosis. Additionally, documentation for isolating and labeling synaptosome substrates derived from human iPSC-derived lower motor neurons (i3LMNs) is provided. A live-cell, longitudinal imaging assay is used to monitor engulfment of human synaptosomes labeled with a pH-sensitive dye, allowing for investigations of iMG's phagocytic capacity. The protocols described herein are broadly applicable to different fields that are investigating human microglia biology and the contribution of microglia to disease.

Human Microglia-like Cells: Differentiation from Induced Pluripotent Stem Cells and In Vitro Live-cell Phagocytosis Assay using Human Synaptosomes

This protocol describes the differentiation process of human induced pluripotent stem cells (iPSCs) into microglia-like cells for in vitro experimentation. We also include a detailed procedure for generating human synaptosomes from iPSC-derived lower motor neurons that can be used as a substrate for in vitro phagocytosis assays using live-cell imaging systems.

Microglia are the resident immune cells of myeloid origin that maintain homeostasis in the brain microenvironment and have become a key player in multiple ...