Partial funding for this work was provided by NSF-CAREER 0744556 (Rao) and a scholarship through the VCU-HHMI Science Education and Research Program (Pascual).

Part 1: Suspension Immunocytochemical Staining
<ol>
 <li>Cells are harvested into a single cell suspension.</li>
 <li>The cells are then transferred into 1.5-2mL microcentrifuge tubes and centrifuged at 200g for 4 minutes.</li>
 <li>Cells are washed by aspirating out supernatant, re-suspended in 1mL of PBS-- (without Mg2+ and Ca2+) and then centrifuged again at 200g for 4 minutes. This should be done twice.</li>
 <li>After washing, cells are then fixed by re-suspending them in 1mL of 4% paraformaldehyde (PFA) at room temperature for 10 minutes. </li>
 <li>Cells are washed again twice with 1mL of PBS--.</li>
 <li>After washing, block cells by re-suspending them in 1mL of Block Solution (6% serum/94% PBS--). Incubate these at room temperature for 45 minutes.</li>
 <li>After, centrifuge tubes at 200g for 4 minutes and aspirate out Block Solution. Re-suspend cells in 1mL of the primary antibody solution (made with Block Solution at recommended dilution). Cells can either be incubated at room temperature for 1 hour or at 4&deg;C overnight before proceeding to the next step.</li>
 <li>Cells are then washed twice with 1mL of Block Solution.</li>
 <li>After, re-suspend cells in 1mL of secondary antibody solution (made with Block Solution at recommended dilution) and incubate at room temperature for 1 hour. </li>
 <li>After 1 hour, cells should then be washed again twice with 1mL of Block Solution. </li>
 <li>After washing with Block Solution, wash cells again with 1mL of PBS--.</li>
 <li>After the various washes, re-suspend cells in 1mL of DAPI nuclear stain (1:10,000 dilution of DAPI in PBS--) and incubate at room temperature for 5 minutes. </li>
 <li>After 5 minutes, centrifuge tubes at 200g for 4 minutes. Aspirate out the DAPI nuclear stain solution and re-suspend cells in 1mL of PBS--.</li>
</ol>
Part 2: Incorporation of hPSCs in slides generated through cytospin apparatus
<ol>
 <li>Plastic slides are prepared by making the desired amount of holes in them with a drill press. The diameter needs to be at most 1mm larger than the widest diameter of the micropipette tip(s) to be used.</li>
 <li>Filter paper is cut to the parameters of the plastic slide with scissors.</li>
 <li>Holes are then made in the filter paper. The size of the hole(s) should be large enough that the micropipette tip(s) fits snuggly through it.</li>
 <li>After, one of the prepared plastic slides is placed on top and a glass slide in placed at the bottom of the cut filter paper (Figure 1). The layers are secured with tape.</li>
 <li>A maximum of 100&mu;L (depending on the desired monolayer density) of the stained cell suspension from Part 1 is then placed into the top of the micropipette tip(s).</li>
 <li>If necessary, the apparatus with cell solution can be weighed and a counter-balance of similar weight created. </li>
 <li>The cytospin apparatus and counter-balance can are then placed in a desktop centrifuge and centrifuged at 200g for 4 minutes.</li>
 <li>After centrifugation, the cytospin apparatus is carefully disassembled in a way that doesn&#8217;t dislodge the cells from the glass slide.</li>
 <li>If necessary, excess surrounding PBS-- on glass side in aspirated out. </li>
 <li>Cells can then be viewed using a fluorescence microscope to check if the desired cell monolayer has been achieved. </li>
</ol>
Part 3: Mounting slides
<ol>
 <li>A drop of the desired mounting media is placed directly in the center of each area containing cells.</li>
 <li>After, a cover slip is gently lowered onto the slides trying to avoid air bubbles if possible.</li>
 <li>Excess mounting media is then removed from slides.</li>
 <li>After, the sides of the cover slips are sealed with nail varnish.</li>
 <li>The slides can be kept in a dark storage area until results are observed and documented. </li>
</ol>

<ol>
	<li>Rao, R. R., Johnson, A. V., Stice, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+surface+markers+in+human+embryonic+stem+cells.">Cell surface markers in human embryonic stem cells.</a> Methods in Mol. Bio. - Stem Cell Assays. 407, 51-61 (2007).</li><li>Sisino, G., Bellavia, D., Corallo, M., Geraci, F., Barbieri, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+homemade+cytospin+apparatus.">A homemade cytospin apparatus.</a> Anal. Biochem. 359, 283-284 (2006).</li></ol>

No conflicts of interest declared.

For the purposes of our lab, a 35mm dish of stem cell cultures grown on mouse embryonic fibroblasts (MEFs) is allotted for the immunocytochemical staining procedure for use with the cytospin apparatus. The cells are then collected by means of enzymatic passaging, removing as much of the MEF layer as possible, into a single-cell suspension. If more effective stem cell isolation from the MEF layer is desired, colonies can be manually picked then digested into suspension. If feeder free conditions are used in growing the st...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Lab Tek Permanox Chamber Slide</td>
<td>&nbsp;</td>
<td>Thermo Fisher Scientific</td>
<td>117437</td>
<td>Material for re-used plastic slides</td>
</tr>
<tr>
<td>Superfrost/Plus Microscope Slides Precleaned</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>12-550-15</td>
<td>&nbsp;</td>
<tr>
<td>0.1-10&mu;L Filter Tips</td>
<td>&nbsp;</td>
<td>USA Scientific</td>
<td>1121-3810</td>
<td>&nbsp;</td>
<tr>
<td>Microscope Cover Glass</td>
<td>&nbsp;</td>
<td>Fisher Scientific</td>
<td>120542-B</td>
<td>&nbsp;</td>
<tr>
<td>Cytoseal 280</td>
<td>&nbsp;</td>
<td>Richard-Allan Scientific</td>
<td>8311-4</td>
<td>Mounting Medium</td>
</tr>
<tr>
<td>DPBS</td>
<td>&nbsp;</td>
<td>Gibco</td>
<td>14190</td>
<td>&nbsp;</td>
<tr>
<td>Normal Goat Serum</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>10000C</td>
<td>&nbsp;</td>
<tr>
<td>Mouse Anti-SSEA-4 Monoclonal Antibody</td>
<td>&nbsp;</td>
<td>Millipore/Chemicon</td>
<td>MAB4304</td>
<td>Primary Antibody for SSEA-4 staining</td>
</tr>
<tr>
<td>Rat Anti-SSEA-3 Monoclonal Antibody</td>
<td>&nbsp;</td>
<td>Millipore/Chemicon</td>
<td>MAB4303</td>
<td>Primary Antibody for SSEA-3 staining</td>
</tr>
<tr>
<td>Alexa Fluor 488 Goat Anti-Mouse IgG</td>
<td>&nbsp;</td>
<td>Invitrogen/ Molecular Probes</td>
<td>A11029</td>
<td>Secondary Antibody for SSEA-4 staining</td>
</tr>
<tr>
<td>Alexa Fluor 488 Labeled Goat Anti-Rat IgG </td>
<td>&nbsp;</td>
<td>Invitrogen/ Molecular Probes</td>
<td>A11006</td>
<td>Secondary Antibody for SSEA-3 staining</td>
</tr>
<tr>
<td>DAPI, Dihydrochloride</td>
<td>&nbsp;</td>
<td>CalBioChem</td>
<td>268298</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

immunocytochemical analysis of human pluripotent stem cells using a self-made cytospin apparatus

Human pluripotent stem cells (hPSCs) that include human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) are exciting cell sources due to their limitless self-renewal capabilities and their potential to differentiate into multiple cell types. The pluripotent state of hPSCs is typically assessed by techniques such as qPCR, immunocytochemistry, and by other in vitro and in vivo differentiation strategies into multiple cell types. Among these, immunocytochemical techniques have been developed for routine characterization of the undifferentiated state of hPSCs based on analysis of candidate intracellular and cell-surface biomarkers. Given the fact that hPSCs grow as colonies, problems arise in quantifying the expression of these markers at the individual cell level on a routine basis. Flow cytometry analyses serve to address this issue but require cell numbers and use of reagents that are not normally conducive for routine quality control assessment of hPSC cultures. Thus, the development of practical and reproducible means of creating monolayer cell samples with preserved integrity for marker evaluation has many advantages in stem cell research. This greatly benefits immunocytochemical analysis because individual cells from the monolayer can be easily observed and quantified for the expression of specific markers. Towards this goal, a self-made cytospin apparatus was constructed and optimized for use with immunocytochemical staining. Two cell-surface markers (SSEA3/SSEA4) expression were analyzed in a variant BG01 stem cell line for the purpose of this protocol.

Watch this Scientific Journal Video about Immunocytochemical Analysis of Human Pluripotent Stem Cells using a Self-Made Cytospin Apparatus at JoVE.com

Immunocytochemical Analysis of Human Pluripotent Stem Cells using a Self-Made Cytospin Apparatus

Suspension immunocytochemical staining of human pluripotent stem cells (hPSCs) for cell-surface markers (SSEA-3/SSEA-4) was achieved based on use of a self-made cytospin apparatus to create a monolayer of cells for observation and quantification.

Human pluripotent stem cells (hPSCs) that include human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) are exciting cell ...

immunocytochemical-analysis-human-pluripotent-stem-cells-using-self

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JoVE Journal

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14.2K Görüntüleme.  Virginia Commonwealth University. Gözlem ve ölçümü için bir tek tabaka hücreleri oluşturmak için bir self-made sitospin cihazların kullanımı dayalı, insan pluripotent kök hücreleri hücre yüzey belirteçleri için Süspansiyon immünositokimyasal boyama (hPSCs) (SSEA-3/SSEA-4) elde edildi.

Video: Immunocytochemical Analysis of Human Pluripotent Stem Cells using a Self-Made Cytospin Apparatus

Analysis of Pluripotent Stem Cells by using Cryosections of Embryoid Bodies

Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of blastocyst-stage early mammalian embryos 1. A crucial stage in the differentiation of ES cells is the formation of embryoid bodies (EBs) aggregates 2, 3. EB formation is based on spontaneous aggregation when ES cells are cultured in non adherent plates. Three-dimensional EB recapitulates many aspects of early mammalian embryogenesis and differentiate into the three germ layers: ectoderm, mesoderm and endoderm 4.
Immunofluorescence and in situ hybridization are widely used techniques for the detection of target proteins and mRNA present in cells of a tissue section 5, 6, 7. Here we present a simple technique to generate high quality cryosections of embryoid bodies. This approach relies on the spatial orientation of EB embedding in OCT followed by the cryosection technique. The resulting sections can be subjected to a wide variety of analytical procedures in order to characterize populations of cells containing certain proteins, RNA or DNA. In this sense, the preparation of EB cryosections (10&mu;m) are essential tools for histology staining analysis (e.g. Hematoxilin and Eosin, DAPI), immunofluorescence (e.g. Oct4, nestin) or in situ hybridization. This technique can also help to understand aspects of embryogenesis with regards to the maintenance of the tri-dimensional spherical structure of EBs.

Pluripotent stem cells growing in suspension differentiate into embryoid bodies (EBs). Here we demonstrate how to obtain high quality EB cryosections useful for studying cellular and molecular aspects of embryogenesis, while preserving their organization as aggregates.

Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of blastocyst-stage early mammalian embryos 1. A crucial stage in the ...

Transfecting and Nucleofecting Human Induced Pluripotent Stem Cells

Genetic modification is continuing to be an essential tool in studying stem cell biology and in setting forth potential clinical applications of human embryonic stem cells (HESCs)1. While improvements in several gene delivery methods have been described2-9, transfection remains a capricious process for HESCs, and has not yet been reported in human induced pluripotent stem cells (iPSCs). In this video, we demonstrate how our lab routinely transfects and nucleofects human iPSCs using plasmid with an enhanced green fluorescence protein (eGFP) reporter. Human iPSCs are adapted and maintained as feeder-free cultures to eliminate the possibility of feeder cell transfection and to allow efficient selection of stable transgenic iPSC clones following transfection. For nucleofection, human iPSCs are pre-treated with ROCK inhibitor11, trypsinized into small clumps of cells, nucleofected and replated on feeders in feeder cell-conditioned medium to enhance cell recovery. Transgene-expressing human iPSCs can be obtained after 6 hours. Antibiotic selection is applied after 24 hours and stable transgenic lines appear within 1 week. Our protocol is robust and reproducible for human iPSC lines without altering pluripotency of these cells.

Despite recent advancements in genetic modification, transfection of human embryonic stem cells (HESCs) remains a capricious process. To our knowledge, systematic and efficient methods to transfect human induced pluripotent stem cells (iPSCs) have not been reported. Here, we describe robust protocols to efficiently transfect and nucleofect human iPSCs.

Genetic modification is continuing to be an essential tool in studying stem cell biology and in setting forth potential clinical applications of human ...

Efficient Derivation of Human Cardiac Precursors and Cardiomyocytes from Pluripotent Human Embryonic Stem Cells with Small Molecule Induction

To date, the lack of a suitable human cardiac cell source has been the major setback in regenerating the human myocardium, either by cell-based transplantation or by cardiac tissue engineering1-3. Cardiomyocytes become terminally-differentiated soon after birth and lose their ability to proliferate. There is no evidence that stem/progenitor cells derived from other sources, such as the bone marrow or the cord blood, are able to give rise to the contractile heart muscle cells following transplantation into the heart1-3. The need to regenerate or repair the damaged heart muscle has not been met by adult stem cell therapy, either endogenous or via cell delivery1-3. The genetically stable human embryonic stem cells (hESCs) have unlimited expansion ability and unrestricted plasticity, proffering a pluripotent reservoir for in vitro derivation of large supplies of human somatic cells that are restricted to the lineage in need of repair and regeneration4,5. Due to the prevalence of cardiovascular disease worldwide and acute shortage of donor organs, there is intense interest in developing hESC-based therapies as an alternative approach. 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 tumorigenicity6-8 (see a schematic in Fig. 1A). 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 problematic9-11. 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 molecules12 (see a schematic in Fig. 1B). After screening a variety of small molecules and growth factors, we found that such defined conditions rendered nicotinamide (NAM) sufficient to induce the specification of cardiomesoderm direct from pluripotent hESCs that further progressed to cardioblasts that generated human beating cardiomyocytes with high efficiency (Fig. 2). We defined conditions for induction of cardioblasts direct from pluripotent hESCs without an intervening multi-lineage embryoid body stage, enabling well-controlled efficient derivation of a large supply of human cardiac cells across the spectrum of developmental stages for cell-based therapeutics.

We have established a protocol for induction of cardioblasts direct from pluripotent human embryonic stem cells maintained under defined conditions with small molecules, which enables derivation of a large supply of human cardiac progenitors and functional cardiomyocytes for cardiovascular repair.

To date, the lack of a suitable human cardiac cell source has been the major setback in regenerating the human myocardium, either by cell-based ...

Reprogramming Human Somatic Cells into Induced Pluripotent Stem Cells (iPSCs) Using Retroviral Vector with GFP

Human embryonic stem cells (hESCs) are pluripotent and an invaluable cellular sources for in vitro disease modeling and regenerative medicine1. It has been previously shown that human somatic cells can be reprogrammed to pluripotency by ectopic expression of four transcription factors (Oct4, Sox2, Klf4 and Myc) and become induced pluripotent stem cells (iPSCs)2-4 . Like hESCs, human iPSCs are pluripotent and a potential source for autologous cells. Here we describe the protocol to reprogram human fibroblast cells with the four reprogramming factors cloned into GFP-containing retroviral backbone4. Using the following protocol, we generate human iPSCs in 3-4 weeks under human ESC culture condition. Human iPSC colonies closely resemble hESCs in morphology and display the loss of GFP fluorescence as a result of retroviral transgene silencing. iPSC colonies isolated mechanically under a fluorescence microscope behave in a similar fashion as hESCs. In these cells, we detect the expression of multiple pluripotency genes and surface markers.

Reprogramming Human Somatic Cells into Induced Pluripotent Stem Cells iPSCs Using Retroviral Vector with GFP

A method to generate human induced pluripotent stem cells (iPSCs) via retrovirus-mediated ectopic expression of OCT4, SOX2, KLF4 and MYC is described. A practical way to identify human iPSC colonies based on GFP expression is also discussed.

Human embryonic stem cells (hESCs) are pluripotent and an invaluable cellular sources for in vitro disease modeling and regenerative medicine1. It has ...

Generation of Human Induced Pluripotent Stem Cells from Peripheral Blood Using the STEMCCA Lentiviral Vector

Through the ectopic expression of four transcription factors, Oct4, Klf4, Sox2 and cMyc, human somatic cells can be converted to a pluripotent state, generating so-called induced pluripotent stem cells (iPSCs)1-4. Patient-specific iPSCs lack the ethical concerns that surround embryonic stem cells (ESCs) and would bypass possible immune rejection. Thus, iPSCs have attracted considerable attention for disease modeling studies, the screening of pharmacological compounds, and regenerative therapies5.
We have shown the generation of transgene-free human iPSCs from patients with different lung diseases using a single excisable polycistronic lentiviral Stem Cell Cassette (STEMCCA) encoding the Yamanaka factors6. These iPSC lines were generated from skin fibroblasts, the most common cell type used for reprogramming. Normally, obtaining fibroblasts requires a skin punch biopsy followed by expansion of the cells in culture for a few passages. Importantly, a number of groups have reported the reprogramming of human peripheral blood cells into iPSCs7-9. In one study, a Tet inducible version of the STEMCCA vector was employed9, which required the blood cells to be simultaneously infected with a constitutively active lentivirus encoding the reverse tetracycline transactivator. In contrast to fibroblasts, peripheral blood cells can be collected via minimally invasive procedures, greatly reducing the discomfort and distress of the patient. A simple and effective protocol for reprogramming blood cells using a constitutive single excisable vector may accelerate the application of iPSC technology by making it accessible to a broader research community. Furthermore, reprogramming of peripheral blood cells allows for the generation of iPSCs from individuals in which skin biopsies should be avoided (i.e. aberrant scarring) or due to pre-existing disease conditions preventing access to punch biopsies.
Here we demonstrate a protocol for the generation of human iPSCs from peripheral blood mononuclear cells (PBMCs) using a single floxed-excisable lentiviral vector constitutively expressing the 4 factors. Freshly collected or thawed PBMCs are expanded for 9 days as described10,11 in medium containing ascorbic acid, SCF, IGF-1, IL-3 and EPO before being transduced with the STEMCCA lentivirus. Cells are then plated onto MEFs and ESC-like colonies can be visualized two weeks after infection. Finally, selected clones are expanded and tested for the expression of the pluripotency markers SSEA-4, Tra-1-60 and Tra-1-81. This protocol is simple, robust and highly consistent, providing a reliable methodology for the generation of human iPSCs from readily accessible 4 ml of blood.

Here we show a simple and effective protocol for the generation of human iPSCs from 3-4 ml of peripheral blood using a single lentiviral reprogramming vector. Reprogramming of readily available blood cells promises to accelerate the utilization of iPSC technology by making it accessible to a broader research community.

Through the ectopic expression of four transcription factors, Oct4, Klf4, Sox2 and cMyc, human somatic cells can be converted to a pluripotent state, ...

Generation of Human Cardiomyocytes: A Differentiation Protocol from Feeder-free Human Induced Pluripotent Stem Cells

In order to investigate the events driving heart development and to determine the molecular mechanisms leading to myocardial diseases in humans, it is essential first to generate functional human cardiomyocytes (CMs). The use of these cells in drug discovery and toxicology studies would also be highly beneficial, allowing new pharmacological molecules for the treatment of cardiac disorders to be validated pre-clinically on cells of human origin. Of the possible sources of CMs, induced pluripotent stem (iPS) cells are among the most promising, as they can be derived directly from readily accessible patient tissue and possess an intrinsic capacity to give rise to all cell types of the body 1. Several methods have been proposed for differentiating iPS cells into CMs, ranging from the classical embryoid bodies (EBs) aggregation approach to chemically defined protocols 2,3. In this article we propose an EBs-based protocol and show how this method can be employed to efficiently generate functional CM-like cells from feeder-free iPS cells.

Pluripotent stem cells, either embryonic or induced pluripotent stem (iPS) cells, constitute a valuable source of human differentiated cells, including cardiomyocytes. Here, we will focus on cardiac induction of iPS cells, showing how to use them to obtain functional human cardiomyocytes through an embryoid bodies-based protocol.

In order to investigate the events driving heart development and to determine the molecular mechanisms leading to myocardial diseases in humans, it is ...

Induction and Analysis of Epithelial to Mesenchymal Transition

Epithelial to mesenchymal transition (EMT) is essential for proper morphogenesis during development. Misregulation of this process has been implicated as a key event in fibrosis and the progression of carcinomas to a metastatic state. Understanding the processes that underlie EMT is imperative for the early diagnosis and clinical control of these disease states. Reliable induction of EMT in vitro is a useful tool for drug discovery as well as to identify common gene expression signatures for diagnostic purposes. Here we demonstrate a straightforward method for the induction of EMT in a variety of cell types. Methods for the analysis of cells pre- and post-EMT induction by immunocytochemistry are also included. Additionally, we demonstrate the effectiveness of this method through antibody-based array analysis and migration/invasion assays.

A straightforward method is described for the induction of epithelial to mesenchymal transition (EMT) in a variety of cell types. Methods for the analysis of cells in EMT states by immunocytochemistry are included.

Epithelial  to mesenchymal transition (EMT) is essential for proper morphogenesis during  development. Misregulation of this  process has been implicated ...

Efficient Generation Human Induced Pluripotent Stem Cells from Human Somatic Cells with Sendai-virus

A few years ago, the establishment of human induced pluripotent stem cells (iPSCs) ushered in a new era in biomedicine. Potential uses of human iPSCs include modeling pathogenesis of human genetic diseases, autologous cell therapy after gene correction, and personalized drug screening by providing a source of patient-specific and symptom relevant cells. However, there are several hurdles to overcome, such as eliminating the remaining reprogramming factor transgene expression after human iPSCs production. More importantly, residual transgene expression in undifferentiated human iPSCs could hamper proper differentiations and misguide the interpretation of disease-relevant in vitro phenotypes. With this reason, integration-free and/or transgene-free human iPSCs have been developed using several methods, such as adenovirus, the piggyBac system, minicircle vector, episomal vectors, direct protein delivery and synthesized mRNA. However, efficiency of reprogramming using integration-free methods is quite low in most cases.
Here, we present a method to isolate human iPSCs by using Sendai-virus (RNA virus) based reprogramming system. This reprogramming method shows consistent results and high efficiency in cost-effective manner.

Here, we present our established method to reprogram human somatic cells into transgene-free human iPSCs with Sendai virus, which shows consistent outcome and enhanced efficiency.

A few years ago, the establishment of human induced pluripotent stem cells (iPSCs) ushered in a new era in biomedicine. Potential uses of human iPSCs ...

A Simple Approach to Perform TEER Measurements Using a Self-Made Volt-Amperemeter with Programmable Output Frequency

Transepithelial/endothelial electrical resistance (TEER) has been used since the 1980s to determine confluency and permeability of in vitro barrier model systems. In most cases, chopstick electrodes are used to determine the electric impedance between the upper and lower compartment of a cell culture filter insert system containing cellular monolayers. The filter membrane allows the cells to adhere, polarize, and interact by building tight junctions. This technique has been described with a variety of different cell lines (e.g., cells of the blood-brain barrier, blood-cerebrospinal fluid barrier, or gastrointestinal and pulmonary tract). TEER measurement devices can be readily obtained from different laboratory equipment suppliers. However, there are more cost-effective and customizable solutions imaginable if an appropriate voltammeter is self-assembled. The overall aim of this publication is to set up a reliable device with programmable output frequency that can be used with commercially available chopstick electrodes for TEER measurement.

Here, we demonstrate how to set up an inexpensive volt-amperemeter with programmable output frequency that can be used with commercially available chopstick electrodes for transepithelial/endothelial electrical resistance measurements.

Transepithelial/endothelial electrical resistance (TEER) has been used since the 1980s to determine confluency and permeability of in vitro barrier model ...

Hepatic Progenitor Specification from Pluripotent Stem Cells using a Defined Differentiation System

Liver disease is an escalating global health issue. While liver transplantation is an effective mode of therapy, patient mortality has increased due to shortages in donor organ availability. Organ scarcity also affects the routine supply of human hepatocytes for basic research and the clinic. Therefore, the development of renewable sources of human liver progenitor cells is desirable and is the goal of this study. To be able to effectively generate and deploy human liver progenitors on a large scale, a reproducible hepatic progenitor differentiation system was developed. This protocol aids experimental reproducibility between users in a range of cell cultureware formats and permits differentiations using both, human embryonic and induced pluripotent stem cell lines. These are important advantages over current differentiation systems that will enhance the basic research and may pave the way towards clinical product development.

The goal of this article is to provide a standardized approach to induce human hepatic progenitor differentiation from pluripotent stem cells. The development of this procedure with ready-to-use media formulations offer the user a facile system to generate human liver cells for biomedical research and translation.

Liver disease is an escalating global health issue. While liver transplantation is an effective mode of therapy, patient mortality has increased due to ...