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’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.
24 Related JoVE Articles!
Generation of Neural Stem Cells from Discarded Human Fetal Cortical Tissue
Institutions: Beth Israel Deaconess Medical Center, Brigham and Women's Hospital, Beth Israel Deaconess Medical Center, Brigham and Women's Hospital.
Neural stem cells (NSCs) reside along the ventricular zone neuroepithelium during the development of the cortical plate. These early progenitors ultimately give rise to intermediate progenitors and later, the various neuronal and glial cell subtypes that form the cerebral cortex. The capacity to generate and expand human NSCs (so called neurospheres) from discarded normal fetal tissue provides a means with which to directly study the functional aspects of normal human NSC development 1-5
. This approach can also be directed toward the generation of NSCs from known neurological disorders, thereby affording the opportunity to identify disease processes that alter progenitor proliferation, migration and differentiation 6-9
. We have focused on identifying pathological mechanisms in human Down syndrome NSCs that might contribute to the accelerated Alzheimer's disease phenotype 10,11
. Neither in vivo
nor in vitro
mouse models can replicate the identical repertoire of genes located on human chromosome 21.
Here we use a simple and reliable method to isolate Down syndrome NSCs from aborted human fetal cortices and grow them in culture. The methodology provides specific aspects of harvesting the tissue, dissection with limited anatomical landmarks, cell sorting, plating and passaging of human NSCs. We also provide some basic protocols for inducing differentiation of human NSCs into more selective cell subtypes.
Neuroscience, Issue 51, neural stem cell, human, brain, cortex, fetus, cell culture
The Neuroblast Assay: An Assay for the Generation and Enrichment of Neuronal Progenitor Cells from Differentiating Neural Stem Cell Progeny Using Flow Cytometry
Institutions: The University of Florida, Shiraz University of Medical Sciences, Shiraz, Iran .
Neural stem cells (NSCs) can be isolated and expanded in large-scale, using the neurosphere assay and differentiated into the three major cell types of the central nervous system (CNS); namely, astrocytes, oligodendrocytes and neurons. These characteristics make neural stem and progenitor cells an invaluable renewable source of cells for in vitro
studies such as drug screening, neurotoxicology and electrophysiology and also for cell replacement therapy in many neurological diseases. In practice, however, heterogeneity of NSC progeny, low production of neurons and oligodendrocytes, and predominance of astrocytes following differentiation limit their clinical applications. Here, we describe a novel methodology for the generation and subsequent purification of immature neurons from murine NSC progeny using fluorescence activated cell sorting (FACS) technology. Using this methodology, a highly enriched neuronal progenitor cell population can be achieved without any noticeable astrocyte and bona fide NSC contamination. The procedure includes differentiation of NSC progeny isolated and expanded from E14 mouse ganglionic eminences using the neurosphere assay, followed by isolation and enrichment of immature neuronal cells based on their physical (size and internal complexity) and fluorescent properties using flow cytometry technology. Overall, it takes 5-7 days to generate neurospheres and 6-8 days to differentiate NSC progeny and isolate highly purified immature neuronal cells.
Neuroscience, Issue 62, neural Stem Cell, Neuronal Progenitor Cells, Flow Cytometry, Isolation, Enrichment
Differentiation of Embryonic Stem Cells into Oligodendrocyte Precursors
Institutions: School of Medicine, University of California, Davis.
Oligodendrocytes are the myelinating cells of the central nervous system. For regenerative cell therapy in demyelinating diseases, there is significant interest in deriving a pure population of lineage-committed oligodendrocyte precursor cells (OPCs) for transplantation. OPCs are characterized by the activity of the transcription factor Olig2 and surface expression of a proteoglycan NG2. Using the GFP-Olig2 (G-Olig2) mouse embryonic stem cell (mESC) reporter line, we optimized conditions for the differentiation of mESCs into GFP+Olig2+NG2+ OPCs. In our protocol, we first describe the generation of embryoid bodies (EBs) from mESCs. Second, we describe treatment of mESC-derived EBs with small molecules: (1) retinoic acid (RA) and (2) a sonic hedgehog (Shh) agonist purmorphamine (Pur) under defined culture conditions to direct EB differentiation into the oligodendroglial lineage. By this approach, OPCs can be obtained with high efficiency (>80%) in a time period of 30 days. Cells derived from mESCs in this protocol are phenotypically similar to OPCs derived from primary tissue culture. The mESC-derived OPCs do not show the spiking property described for a subpopulation of brain OPCs in situ. To study this electrophysiological property, we describe the generation of spiking mESC-derived OPCs by ectopically expressing NaV
1.2 subunit. The spiking and nonspiking cells obtained from this protocol will help advance functional studies on the two subpopulations of OPCs.
Neurobiology, Issue 39, pluripotent stem cell, oligodendrocyte precursor cells, differentiation, myelin, neuroscience, brain
A High-throughput Automated Platform for the Development of Manufacturing Cell Lines for Protein Therapeutics
Institutions: Merck & Co., Inc.
The fast-growing biopharmaceutical industry demands speedy development of highly efficient and reliable production systems to meet the increasing requirement for drug supplies. The generation of production cell lines has traditionally involved manual operations that are labor-intensive, low-throughput and vulnerable to human errors. We report here an integrated high-throughput and automated platform for development of manufacturing cell lines for the production of protein therapeutics.
The combination of BD FACS Aria Cell Sorter, CloneSelect Imager and TECAN Freedom EVO liquid handling system has enabled a high-throughput and more efficient cell line development process. In this operation, production host cells are first transfected with an expression vector carrying the gene of interest 1
, followed by the treatment with a selection agent. The stably-transfected cells are then stained with fluorescence-labeled anti-human IgG antibody, and are subsequently subject to flow cytometry analysis 2-4
. Highly productive cells are selected based on fluorescence intensity and are isolated by single-cell sorting on a BD FACSAria. Colony formation from single-cell stage was detected microscopically and a series of time-laps digital images are taken by CloneSelect Imager for the documentation of cell line history. After single clones have formed, these clones were screened for productivity by ELISA performed on a TECAN Freedom EVO liquid handling system. Approximately 2,000 - 10,000 clones can be screened per operation cycle with the current system setup.
This integrated approach has been used to generate high producing Chinese hamster ovary (CHO) cell lines for the production of therapeutic monoclonal antibody (mAb) as well as their fusion proteins. With the aid of different types of detecting probes, the method can be used for developing other protein therapeutics or be applied to other production host systems. Comparing to the traditional manual procedure, this automated platform demonstrated advantages of significantly increased capacity, ensured clonality, traceability in cell line history with electronic documentation and much reduced opportunity in operator error.
Medicine, Issue 55, Manufacturing cell line, protein therapeutics, automation, high-throughput, FACS, FACS Aria, CloneSelect Imager, TECAN Freedom EVO liquid handling system
Organotypic Slice Cultures of Embryonic Ventral Midbrain: A System to Study Dopaminergic Neuronal Development in vitro
Institutions: University of Bonn.
The mouse is an excellent model organism to study mammalian brain development due to the abundance of molecular and genetic data. However, the developing mouse brain is not suitable for easy manipulation and imaging in vivo
since the mouse embryo is inaccessible and opaque. Organotypic slice cultures of embryonic brains are therefore widely used to study murine brain development in vitro
manipulation or the use of transgenic mice allows the modification of gene expression so that subpopulations of neuronal or glial cells can be labeled with fluorescent proteins. The behavior of labeled cells can then be observed using time-lapse imaging. Time-lapse imaging has been particularly successful for studying cell behaviors that underlie the development of the cerebral cortex at late embryonic stages 1-2
. Embryonic organotypic slice culture systems in brain regions outside of the forebrain are less well established. Therefore, the wealth of time-lapse imaging data describing neuronal cell migration is restricted to the forebrain 3,4
. It is still not known, whether the principles discovered for the dorsal brain hold true for ventral brain areas. In the ventral brain, neurons are organized in neuronal clusters rather than layers and they often have to undergo complicated migratory trajectories to reach their final position. The ventral midbrain is not only a good model system for ventral brain development, but also contains neuronal populations such as dopaminergic neurons that are relevant in disease processes. While the function and degeneration of dopaminergic neurons has been investigated in great detail in the adult and ageing brain, little is known about the behavior of these neurons during their differentiation and migration phase 5
. We describe here the generation of slice cultures from the embryonic day (E) 12.5 mouse ventral midbrain. These slice cultures are potentially suitable for monitoring dopaminergic neuron development over several days in vitro
. We highlight the critical steps in generating brain slices at these early stages of embryonic development and discuss the conditions necessary for maintaining normal development of dopaminergic neurons in vitro
. We also present results from time lapse imaging experiments. In these experiments, ventral midbrain precursors (including dopaminergic precursors) and their descendants were labeled in a mosaic manner using a Cre/loxP based inducible fate mapping system 6
Neuroscience, Issue 59, Developmental Biology, organotypic slice culture, midbrain, mouse, time-lapse imaging, neurons
The Specification of Telencephalic Glutamatergic Neurons from Human Pluripotent Stem Cells
Institutions: The University of Connecticut Health Center, The University of Connecticut Health Center, The University of Connecticut Health Center.
Here, a stepwise procedure for efficiently generating telencephalic glutamatergic neurons from human pluripotent stem cells (PSCs) has been described. The differentiation process is initiated by breaking the human PSCs into clumps which round up to form aggregates when the cells are placed in a suspension culture. The aggregates are then grown in hESC medium from days 1-4 to allow for spontaneous differentiation. During this time, the cells have the capacity to become any of the three germ layers. From days 5-8, the cells are placed in a neural induction medium to push them into the neural lineage. Around day 8, the cells are allowed to attach onto 6 well plates and differentiate during which time the neuroepithelial cells form. These neuroepithelial cells can be isolated at day 17. The cells can then be kept as neurospheres until they are ready to be plated onto coverslips. Using a basic medium without any caudalizing factors, neuroepithelial cells are specified into telencephalic precursors, which can then be further differentiated into dorsal telencephalic progenitors and glutamatergic neurons efficiently. Overall, our system provides a tool to generate human glutamatergic neurons for researchers to study the development of these neurons and the diseases which affect them.
Stem Cell Biology, Issue 74, Neuroscience, Neurobiology, Developmental Biology, Cellular Biology, Molecular Biology, Stem Cells, Embryonic Stem Cells, ESCs, Pluripotent Stem Cells, Induced Pluripotent Stem Cells, iPSC, neural differentiation, forebrain, glutamatergic neuron, neural patterning, development, neurons
Derivation of Glial Restricted Precursors from E13 mice
Institutions: Johns Hopkins University, Johns Hopkins School of Medicine, University of Maryland , Biogen Idec, Johns Hopkins School of Medicine, Johns Hopkins School of Medicine.
This is a protocol for derivation of glial restricted precursor (GRP) cells from the spinal cord of E13 mouse fetuses. These cells are early precursors within the oligodendrocytic cell lineage. Recently, these cells have been studied as potential source for restorative therapies in white matter diseases. Periventricular leukomalacia (PVL) is the leading cause of non-genetic white matter disease in childhood and affects up to 50% of extremely premature infants. The data suggest a heightened susceptibility of the developing brain to hypoxia-ischemia, oxidative stress and excitotoxicity that selectively targets nascent white matter. Glial restricted precursors (GRP), oligodendrocyte progenitor cells (OPC) and immature oligodendrocytes (preOL) seem to be key players in the development of PVL and are the subject of continuing studies. Furthermore, previous studies have identified a subset of CNS tissue that has increased susceptibility to glutamate excitotoxicity as well as a developmental pattern to this susceptibility. Our laboratory is currently investigating the role of oligodendrocyte progenitors in PVL and use cells at the GRP stage of development. We utilize these derived GRP cells in several experimental paradigms to test their response to select stresses consistent with PVL. GRP cells can be manipulated in vitro
into OPCs and preOL for transplantation experiments with mouse PVL models and in vitro
models of PVL-like insults including hypoxia-ischemia. By using cultured cells and in vitro
studies there would be reduced variability between experiments which facilitates interpretation of the data. Cultured cells also allows for enrichment of the GRP population while minimizing the impact of contaminating cells of non-GRP phenotype.
Neuroscience, Issue 64, Physiology, Medicine, periventricular leukomalacia, oligodendrocytes, glial restricted precursors, spinal cord, cell culture
Adult and Embryonic Skeletal Muscle Microexplant Culture and Isolation of Skeletal Muscle Stem Cells
Institutions: University of Birmingham.
Cultured embryonic and adult skeletal muscle cells have a number of different uses. The micro-dissected explants technique described in this chapter is a robust and reliable method for isolating relatively large numbers of proliferative skeletal muscle cells from juvenile, adult or embryonic muscles as a source of skeletal muscle stem cells. The authors have used micro-dissected explant cultures to analyse the growth characteristics of skeletal muscle cells in wild-type and dystrophic muscles. Each of the components of tissue growth, namely cell survival, proliferation, senescence and differentiation can be analysed separately using the methods described here. The net effect of all components of growth can be established by means of measuring explant outgrowth rates. The micro-explant method can be used to establish primary cultures from a wide range of different muscle types and ages and, as described here, has been adapted by the authors to enable the isolation of embryonic skeletal muscle precursors.
Uniquely, micro-explant cultures have been used to derive clonal (single cell origin) skeletal muscle stem cell (SMSc) lines which can be expanded and used for in vivo
transplantation. In vivo
transplanted SMSc behave as functional, tissue-specific, satellite cells which contribute to skeletal muscle fibre regeneration but which are also retained (in the satellite cell niche) as a small pool of undifferentiated stem cells which can be re-isolated into culture using the micro-explant method.
Cellular Biology, Issue 43, Skeletal muscle stem cell, embryonic tissue culture, apoptosis, growth factor, proliferation, myoblast, myogenesis, satellite cell, skeletal muscle differentiation, muscular dystrophy
Dissection and Culture of Mouse Dopaminergic and Striatal Explants in Three-Dimensional Collagen Matrix Assays
Institutions: University Medical Center Utrecht.
Midbrain dopamine (mdDA) neurons project via the medial forebrain bundle towards several areas in the telencephalon, including the striatum1
. Reciprocally, medium spiny neurons in the striatum that give rise to the striatonigral (direct) pathway innervate the substantia nigra2
. The development of these axon tracts is dependent upon the combinatorial actions of a plethora of axon growth and guidance cues including molecules that are released by neurites or by (intermediate) target regions3,4
. These soluble factors can be studied in vitro
by culturing mdDA and/or striatal explants in a collagen matrix which provides a three-dimensional substrate for the axons mimicking the extracellular environment. In addition, the collagen matrix allows for the formation of relatively stable gradients of proteins released by other explants or cells placed in the vicinity (e.g. see references 5 and 6). Here we describe methods for the purification of rat tail collagen, microdissection of dopaminergic and striatal explants, their culture in collagen gels and subsequent immunohistochemical and quantitative analysis. First, the brains of E14.5 mouse embryos are isolated and dopaminergic and striatal explants are microdissected. These explants are then (co)cultured in collagen gels on coverslips for 48 to 72 hours in vitro
. Subsequently, axonal projections are visualized using neuronal markers (e.g. tyrosine hydroxylase, DARPP32, or βIII tubulin) and axon growth and attractive or repulsive axon responses are quantified. This neuronal preparation is a useful tool for in vitro
studies of the cellular and molecular mechanisms of mesostriatal and striatonigral axon growth and guidance during development. Using this assay, it is also possible to assess other (intermediate) targets for dopaminergic and striatal axons or to test specific molecular cues.
Neuroscience, Issue 61, Axon guidance, collagen matrix, development, dissection, dopamine, medium spiny neuron, rat tail collagen, striatum, striatonigral, mesostriatal
A cGMP-applicable Expansion Method for Aggregates of Human Neural Stem and Progenitor Cells Derived From Pluripotent Stem Cells or Fetal Brain Tissue
Institutions: Cedars-Sinai Medical Center.
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 “chopping” 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.
Neuroscience, Issue 88, neural progenitor cell, neural precursor cell, neural stem cell, passaging, neurosphere, chopping, stem cell, neuroscience, suspension culture, good manufacturing practice, GMP
Isolation of Blood-vessel-derived Multipotent Precursors from Human Skeletal Muscle
Institutions: University of Pittsburgh, University of Pittsburgh, Nazarbayev University, University of California at Los Angeles, Erasmus MC Stem Cell Institute, Oregon Health & Science University, Queen's Medical Research Institute and University of Edinburgh, University of California at Los Angeles, University of Pittsburgh.
Since the discovery of mesenchymal stem/stromal cells (MSCs), the native identity and localization of MSCs
have been obscured by their retrospective isolation in culture. Recently, using fluorescence-activated cell sorting (FACS), we and other researchers prospectively identified and purified three subpopulations of multipotent precursor cells associated with the vasculature of human skeletal muscle. These three cell populations: myogenic endothelial cells (MECs), pericytes (PCs), and adventitial cells (ACs), are localized respectively to the three structural layers of blood vessels: intima, media, and adventitia. All of these human blood-vessel-derived stem cell (hBVSC) populations not only express classic MSC markers but also possess mesodermal developmental potentials similar to typical MSCs. Previously, MECs, PCs, and ACs have been isolated through distinct protocols and subsequently characterized in separate studies. The current isolation protocol, through modifications to the isolation process and adjustments in the selective cell surface markers, allows us to simultaneously purify all three hBVSC subpopulations by FACS from a single human muscle biopsy. This new method will not only streamline the isolation of multiple BVSC subpopulations but also facilitate future clinical applications of hBVSCs for distinct therapeutic purposes.
Cellular Biology, Issue 90, Blood Vessel; Pericyte; Adventitial Cell; Myogenic Endothelial Cell; Multipotent Precursor
High Efficiency Differentiation of Human Pluripotent Stem Cells to Cardiomyocytes and Characterization by Flow Cytometry
Institutions: Medical College of Wisconsin, Stanford University School of Medicine, Medical College of Wisconsin, Hong Kong University, Johns Hopkins University School of Medicine, Medical College of Wisconsin.
There is an urgent need to develop approaches for repairing the damaged heart, discovering new therapeutic drugs that do not have toxic effects on the heart, and improving strategies to accurately model heart disease. The potential of exploiting human induced pluripotent stem cell (hiPSC) technology to generate cardiac muscle “in a dish” for these applications continues to generate high enthusiasm. In recent years, the ability to efficiently generate cardiomyogenic cells from human pluripotent stem cells (hPSCs) has greatly improved, offering us new opportunities to model very early stages of human cardiac development not otherwise accessible. In contrast to many previous methods, the cardiomyocyte differentiation protocol described here does not require cell aggregation or the addition of Activin A or BMP4 and robustly generates cultures of cells that are highly positive for cardiac troponin I and T (TNNI3, TNNT2), iroquois-class homeodomain protein IRX-4 (IRX4), myosin regulatory light chain 2, ventricular/cardiac muscle isoform (MLC2v) and myosin regulatory light chain 2, atrial isoform (MLC2a) by day 10 across all human embryonic stem cell (hESC) and hiPSC lines tested to date. Cells can be passaged and maintained for more than 90 days in culture. The strategy is technically simple to implement and cost-effective. Characterization of cardiomyocytes derived from pluripotent cells often includes the analysis of reference markers, both at the mRNA and protein level. For protein analysis, flow cytometry is a powerful analytical tool for assessing quality of cells in culture and determining subpopulation homogeneity. However, technical variation in sample preparation can significantly affect quality of flow cytometry data. Thus, standardization of staining protocols should facilitate comparisons among various differentiation strategies. Accordingly, optimized staining protocols for the analysis of IRX4, MLC2v, MLC2a, TNNI3, and TNNT2 by flow cytometry are described.
Cellular Biology, Issue 91, human induced pluripotent stem cell, flow cytometry, directed differentiation, cardiomyocyte, IRX4, TNNI3, TNNT2, MCL2v, MLC2a
Promotion of Survival and Differentiation of Neural Stem Cells with Fibrin and Growth Factor Cocktails after Severe Spinal Cord Injury
Institutions: Veterans Administration Medical Center, San Diego, University of California, San Diego.
Neural stem cells (NSCs) can self-renew and differentiate into neurons and glia. Transplanted NSCs can replace lost neurons and glia after spinal cord injury (SCI), and can form functional relays to re-connect spinal cord segments above and below a lesion. Previous studies grafting neural stem cells have been limited by incomplete graft survival within the spinal cord lesion cavity. Further, tracking of graft cell survival, differentiation, and process extension had not been optimized. Finally, in previous studies, cultured rat NSCs were typically reported to differentiate into glia when grafted to the injured spinal cord, rather than neurons, unless fate was driven to a specific cell type. To address these issues, we developed new methods to improve the survival, integration and differentiation of NSCs to sites of even severe SCI. NSCs were freshly isolated from embryonic day 14 spinal cord (E14) from a stable transgenic Fischer 344 rat line expressing green fluorescent protein (GFP) and were embedded into a fibrin matrix containing growth factors; this formulation aimed to retain grafted cells in the lesion cavity and support cell survival. NSCs in the fibrin/growth factor cocktail were implanted two weeks after thoracic level-3 (T3) complete spinal cord transections, thereby avoiding peak periods of inflammation. Resulting grafts completely filled the lesion cavity and differentiated into both neurons, which extended axons into the host spinal cord over remarkably long distances, and glia. Grafts of cultured human NSCs expressing GFP resulted in similar findings. Thus, methods are defined for improving neural stem cell grafting, survival and analysis of in vivo
Neuroscience, Issue 89, nervous system diseases, wounds and injuries, biological factors, therapeutics, surgical procedures, neural stem cells, transplantation, spinal cord injury, fibrin, growth factors
Genetic Manipulation in Δku80 Strains for Functional Genomic Analysis of Toxoplasma gondii
Institutions: The Geisel School of Medicine at Dartmouth.
Targeted genetic manipulation using homologous recombination is the method of choice for functional genomic analysis to obtain a detailed view of gene function and phenotype(s). The development of mutant strains with targeted gene deletions, targeted mutations, complemented gene function, and/or tagged genes provides powerful strategies to address gene function, particularly if these genetic manipulations can be efficiently targeted to the gene locus of interest using integration mediated by double cross over homologous recombination.
Due to very high rates of nonhomologous recombination, functional genomic analysis of Toxoplasma gondii
has been previously limited by the absence of efficient methods for targeting gene deletions and gene replacements to specific genetic loci. Recently, we abolished the major pathway of nonhomologous recombination in type I and type II strains of T. gondii
by deleting the gene encoding the KU80 protein1,2
. The Δku80
strains behave normally during tachyzoite (acute) and bradyzoite (chronic) stages in vitro
and in vivo
and exhibit essentially a 100% frequency of homologous recombination. The Δku80
strains make functional genomic studies feasible on the single gene as well as on the genome scale1-4
Here, we report methods for using type I and type II Δku80Δhxgprt
strains to advance gene targeting approaches in T. gondii
. We outline efficient methods for generating gene deletions, gene replacements, and tagged genes by targeted insertion or deletion of the hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT
) selectable marker. The described gene targeting protocol can be used in a variety of ways in Δku80
strains to advance functional analysis of the parasite genome and to develop single strains that carry multiple targeted genetic manipulations. The application of this genetic method and subsequent phenotypic assays will reveal fundamental and unique aspects of the biology of T. gondii
and related significant human pathogens that cause malaria (Plasmodium
sp.) and cryptosporidiosis (Cryptosporidium
Infectious Diseases, Issue 77, Genetics, Microbiology, Infection, Medicine, Immunology, Molecular Biology, Cellular Biology, Biomedical Engineering, Bioengineering, Genomics, Parasitology, Pathology, Apicomplexa, Coccidia, Toxoplasma, Genetic Techniques, Gene Targeting, Eukaryota, Toxoplasma gondii, genetic manipulation, gene targeting, gene deletion, gene replacement, gene tagging, homologous recombination, DNA, sequencing
Primary Culture of Mouse Dopaminergic Neurons
Institutions: Institut de Génomique Fonctionnelle, Montpellier, U661, Montpellier, Universités de Montpellier.
Dopaminergic neurons represent less than 1% of the total number of neurons in the brain. This low amount of neurons regulates important brain functions such as motor control, motivation, and working memory. Nigrostriatal dopaminergic neurons selectively degenerate in Parkinson's disease (PD). This progressive neuronal loss is unequivocally associated with the motors symptoms of the pathology (bradykinesia, resting tremor, and muscular rigidity). The main agent responsible of dopaminergic neuron degeneration is still unknown. However, these neurons appear to be extremely vulnerable in diverse conditions. Primary cultures constitute one of the most relevant models to investigate properties and characteristics of dopaminergic neurons. These cultures can be submitted to various stress agents that mimic PD pathology and to neuroprotective compounds in order to stop or slow down neuronal degeneration. The numerous transgenic mouse models of PD that have been generated during the last decade further increased the interest of researchers for dopaminergic neuron cultures. Here, the video protocol focuses on the delicate dissection of embryonic mouse brains. Precise excision of ventral mesencephalon is crucial to obtain neuronal cultures sufficiently rich in dopaminergic cells to allow subsequent studies. This protocol can be realized with embryonic transgenic mice and is suitable for immunofluorescence staining, quantitative PCR, second messenger quantification, or neuronal death/survival assessment.
Neurobiology, Issue 91, Mus musculus, mesencephalon, embryonic, tyrosine hydroxylase, dopamine transporter, Parkinson's disease in vitro model
Systemic Injection of Neural Stem/Progenitor Cells in Mice with Chronic EAE
Institutions: University of Cambridge, UK, University of Cambridge, UK.
Neural stem/precursor cells (NPCs) are a promising stem cell source for transplantation approaches aiming at brain repair or restoration in regenerative neurology. This directive has arisen from the extensive evidence that brain repair is achieved after focal or systemic NPC transplantation in several preclinical models of neurological diseases.
These experimental data have identified the cell delivery route as one of the main hurdles of restorative stem cell therapies for brain diseases that requires urgent assessment. Intraparenchymal stem cell grafting represents a logical approach to those pathologies characterized by isolated and accessible brain lesions such as spinal cord injuries and Parkinson's disease. Unfortunately, this principle is poorly applicable to conditions characterized by a multifocal, inflammatory and disseminated (both in time and space) nature, including multiple sclerosis (MS). As such, brain targeting by systemic NPC delivery has become a low invasive and therapeutically efficacious protocol to deliver cells to the brain and spinal cord of rodents and nonhuman primates affected by experimental chronic inflammatory damage of the central nervous system (CNS).
This alternative method of cell delivery relies on the NPC pathotropism, specifically their innate capacity to (i) sense the environment via
functional cell adhesion molecules and inflammatory cytokine and chemokine receptors; (ii) cross the leaking anatomical barriers after intravenous (i.v
.) or intracerebroventricular (i.c.v.
) injection; (iii) accumulate at the level of multiple perivascular site(s) of inflammatory brain and spinal cord damage; and (i.v.
) exert remarkable tissue trophic and immune regulatory effects onto different host target cells in vivo
Here we describe the methods that we have developed for the i.v
. and i.c.v.
delivery of syngeneic NPCs in mice with experimental autoimmune encephalomyelitis (EAE), as model of chronic CNS inflammatory demyelination, and envisage the systemic stem cell delivery as a valuable technique for the selective targeting of the inflamed brain in regenerative neurology.
Immunology, Issue 86, Somatic neural stem/precursor cells, neurodegenerative disorders, regenerative medicine, multiple sclerosis, experimental autoimmune encephalomyelitis, systemic delivery, intravenous, intracerebroventricular
Lineage-reprogramming of Pericyte-derived Cells of the Adult Human Brain into Induced Neurons
Institutions: Ludwig Maximilians University Munich, Ludwig-Maximilians University Munich, Friedrich-Alexander-Universität Erlangen-Nürnberg, Johannes Gutenberg University Mainz.
Direct lineage-reprogramming of non-neuronal cells into induced neurons (iNs) may provide insights into the molecular mechanisms underlying neurogenesis and enable new strategies for in vitro
modeling or repairing the diseased brain. Identifying brain-resident non-neuronal cell types amenable to direct conversion into iNs might allow for launching such an approach in situ
within the damaged brain tissue. Here we describe a protocol developed in the attempt of identifying cells derived from the adult human brain that fulfill this premise. This protocol involves: (1) the culturing of human cells from the cerebral cortex obtained from adult human brain biopsies; (2) the in vitro
expansion (approximately requiring 2-4 weeks) and characterization of the culture by immunocytochemistry and flow cytometry; (3) the enrichment by fluorescence-activated cell sorting (FACS) using anti-PDGF receptor-β and anti-CD146 antibodies; (4) the retrovirus-mediated transduction with the neurogenic transcription factors sox2 and ascl1; (5) and finally the characterization of the resultant pericyte-derived induced neurons (PdiNs) by immunocytochemistry (14 days to 8 weeks following retroviral transduction). At this stage, iNs can be probed for their electrical properties by patch-clamp recording. This protocol provides a highly reproducible procedure for the in vitro
lineage conversion of brain-resident pericytes into functional human iNs.
Neuroscience, Issue 87, Pericytes, lineage-reprogramming, induced neurons, cerebral cortex
Zinc-finger Nuclease Enhanced Gene Targeting in Human Embryonic Stem Cells
Institutions: Monash University.
One major limitation with current human embryonic stem cell (ESC) differentiation protocols is the generation of heterogeneous cell populations. These cultures contain the cells of interest, but are also contaminated with undifferentiated ESCs, non-neural derivatives and other neuronal subtypes. This limits their use in in vitro
and in vivo
applications, such as in vitro
modeling for drug discovery or cell replacement therapy. To help overcome this, reporter cell lines, which offer a means to visualize, track and isolate cells of interest, can be engineered. However, to achieve this in human embryonic stem cells via conventional homologous recombination is extremely inefficient. This protocol describes targeting of the Pituitary homeobox 3
) locus in human embryonic stem cells using custom designed zinc-finger nucleases, which introduce site-specific double-strand DNA breaks, together with a PITX3
-specific DNA donor vector. Following the generation of the PITX3
reporter cell line, it can then be differentiated using published protocols for use in studies such as in vitro
Parkinson’s disease modeling or cell replacement therapy.
Molecular Biology, Issue 90, Electroporation, human embryonic stem cell, genome editing, reporter cell line, midbrain dopaminergic neurons
Setting-up an In Vitro Model of Rat Blood-brain Barrier (BBB): A Focus on BBB Impermeability and Receptor-mediated Transport
Institutions: VECT-HORUS SAS, CNRS, NICN UMR 7259.
The blood brain barrier (BBB) specifically regulates molecular and cellular flux between the blood and the nervous tissue. Our aim was to develop and characterize a highly reproducible rat syngeneic in vitro
model of the BBB using co-cultures of primary rat brain endothelial cells (RBEC) and astrocytes to study receptors involved in transcytosis across the endothelial cell monolayer. Astrocytes were isolated by mechanical dissection following trypsin digestion and were frozen for later co-culture. RBEC were isolated from 5-week-old rat cortices. The brains were cleaned of meninges and white matter, and mechanically dissociated following enzymatic digestion. Thereafter, the tissue homogenate was centrifuged in bovine serum albumin to separate vessel fragments from nervous tissue. The vessel fragments underwent a second enzymatic digestion to free endothelial cells from their extracellular matrix. The remaining contaminating cells such as pericytes were further eliminated by plating the microvessel fragments in puromycin-containing medium. They were then passaged onto filters for co-culture with astrocytes grown on the bottom of the wells. RBEC expressed high levels of tight junction (TJ) proteins such as occludin, claudin-5 and ZO-1 with a typical localization at the cell borders. The transendothelial electrical resistance (TEER) of brain endothelial monolayers, indicating the tightness of TJs reached 300 ohm·cm2
on average. The endothelial permeability coefficients (Pe) for lucifer yellow (LY) was highly reproducible with an average of 0.26 ± 0.11 x 10-3
cm/min. Brain endothelial cells organized in monolayers expressed the efflux transporter P-glycoprotein (P-gp), showed a polarized transport of rhodamine 123, a ligand for P-gp, and showed specific transport of transferrin-Cy3 and DiILDL across the endothelial cell monolayer. In conclusion, we provide a protocol for setting up an in vitro
BBB model that is highly reproducible due to the quality assurance methods, and that is suitable for research on BBB transporters and receptors.
Medicine, Issue 88, rat brain endothelial cells (RBEC), mouse, spinal cord, tight junction (TJ), receptor-mediated transport (RMT), low density lipoprotein (LDL), LDLR, transferrin, TfR, P-glycoprotein (P-gp), transendothelial electrical resistance (TEER),
Modeling Astrocytoma Pathogenesis In Vitro and In Vivo Using Cortical Astrocytes or Neural Stem Cells from Conditional, Genetically Engineered Mice
Institutions: University of North Carolina School of Medicine, University of North Carolina School of Medicine, University of North Carolina School of Medicine, University of North Carolina School of Medicine, University of North Carolina School of Medicine, Emory University School of Medicine, University of North Carolina School of Medicine.
Current astrocytoma models are limited in their ability to define the roles of oncogenic mutations in specific brain cell types during disease pathogenesis and their utility for preclinical drug development. In order to design a better model system for these applications, phenotypically wild-type cortical astrocytes and neural stem cells (NSC) from conditional, genetically engineered mice (GEM) that harbor various combinations of floxed oncogenic alleles were harvested and grown in culture. Genetic recombination was induced in vitro
using adenoviral Cre-mediated recombination, resulting in expression of mutated oncogenes and deletion of tumor suppressor genes. The phenotypic consequences of these mutations were defined by measuring proliferation, transformation, and drug response in vitro
. Orthotopic allograft models, whereby transformed cells are stereotactically injected into the brains of immune-competent, syngeneic littermates, were developed to define the role of oncogenic mutations and cell type on tumorigenesis in vivo
. Unlike most established human glioblastoma cell line xenografts, injection of transformed GEM-derived cortical astrocytes into the brains of immune-competent littermates produced astrocytomas, including the most aggressive subtype, glioblastoma, that recapitulated the histopathological hallmarks of human astrocytomas, including diffuse invasion of normal brain parenchyma. Bioluminescence imaging of orthotopic allografts from transformed astrocytes engineered to express luciferase was utilized to monitor in vivo
tumor growth over time. Thus, astrocytoma models using astrocytes and NSC harvested from GEM with conditional oncogenic alleles provide an integrated system to study the genetics and cell biology of astrocytoma pathogenesis in vitro
and in vivo
and may be useful in preclinical drug development for these devastating diseases.
Neuroscience, Issue 90, astrocytoma, cortical astrocytes, genetically engineered mice, glioblastoma, neural stem cells, orthotopic allograft
ES Cell-derived Neuroepithelial Cell Cultures
Institutions: Harvard Medical School.
ES cells have the potential to differentiate into cells from all germ layers, which makes them an attractive tool for the development of new therapies. In general, the differentiation of ES cells follows the concept to first generate immature progenitor cells, which then can be propagated and differentiated into mature cellular phenotypes. This also applies for ES cell-derived neurogenesis, in which the development of neural cells follows two major steps: First, the derivation and expansion of immature neuroepithelial precursors and second, their differentiation into mature neural cells. A common method to produce neural progenitors from ES cells is based on embryoid body (EB) formation, which reveals the differentiation of cells from all germ layers including neuroectoderm. An alternative and more efficient method to induce neuroepithelial cell development uses stromal cell-derived inducing activity (SDIA), which can be achieved by co-culturing ES cells with skull bone marrow-derived stromal cells (1). Both, EB formation and SDIA, reveal the development of rosette-like structures, which are thought to resemble neural tube- and/or neural crest-like progenitors. The neural precursors can be isolated, expanded and further differentiated into specific neurons and glia cells using defined culture conditions. Here, we describe the generation and isolation of such rosettes in co-culture experiments with the stromal cell line MS5 (2-5).
Cellular Biology, issue 1, embryonic stem (ES) cells, rosettes, neuroepithelial precursors, stromal cells, differentiation
Targeted Expression of GFP in the Hair Follicle Using Ex Vivo Viral Transduction
Institutions: AntiCancer, Inc..
There are many cell types in the hair follicle, including hair matrix cells which form the hair shaft and stem cells which can initiate the hair shaft during early anagen, the growth phase of the hair cycle, as well as pluripotent stem cells that play a role in hair follicle growth but have the potential to differentiate to non-follicle cells such as neurons. These properties of the hair follicle are discussed. The various cell types of the hair follicle are potential targets for gene therapy. Gene delivery system for the hair follicle using viral vectors or liposomes for gene targeting to the various cell types in the hair follicle and the results obtained are also discussed.
Cellular Biology, Issue 13, Springer Protocols, hair follicles, liposomes, adenovirus, genes, stem cells
Propagation of Human Embryonic Stem (ES) Cells
Institutions: MGH - Massachusetts General Hospital.
Cellular Biology, Issue 1, ES, embryonic stem cells, tissue culture
Ole Isacson: Development of New Therapies for Parkinson's Disease
Institutions: Harvard Medical School.
Medicine, Issue 3, Parkinson' disease, Neuroscience, dopamine, neuron, L-DOPA, stem cell, transplantation