The mouse heterotopic heart transplantation has been used widely since it was introduced by Drs. Corry and Russell in 1973. It is particularly valuable for studying rejection and immune response now that newer transgenic and gene knockout mice are available, and a large number of immunologic reagents have been developed. The heart transplant model is less stringent than the skin transplant models, although technically more challenging. We have developed a modified technique and have completed over 1000 successful cases of heterotopic heart transplantation in mice. When making anastomosis of the ascending aorta and abdominal aorta, two stay sutures are placed at the proximal and distal apexes of recipient abdominal aorta with the donor s ascending aorta, then using 11-0 suture for anastomosis on both side of aorta with continuing sutures. The stay sutures make the anastomosis easier and 11-0 is an ideal suture size to avoid bleeding and thrombosis.
When making anastomosis of pulmonary artery and inferior vena cava, two stay sutures are made at the proximal apex and distal apex of the recipient s inferior vena cava with the donor s pulmonary artery. The left wall of the inferior vena cava and donor s pulmonary artery is closed with continuing sutures in the inside of the inferior vena cava after, one knot with the proximal apex stay suture the right wall of the inferior vena cava and the donor s pulmonary artery are closed with continuing sutures outside the inferior vena cave with 10-0 sutures. This method is easier to perform because anastomosis is made just on the one side of the inferior vena cava and 10-0 sutures is the right size to avoid bleeding and thrombosis. In this article, we provide details of the technique to supplement the video.
21 Related JoVE Articles!
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
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
Derivation of Cardiac Progenitor Cells from Embryonic Stem Cells
Institutions: University of Michigan, New York University School of Medicine.
Cardiac progenitor cells (CPCs) have the capacity to differentiate into cardiomyocytes, smooth muscle cells (SMC), and endothelial cells and hold great promise in cell therapy against heart disease. Among various methods to isolate CPCs, differentiation of embryonic stem cell (ESC) into CPCs attracts great attention in the field since ESCs can provide unlimited cell source. As a result, numerous strategies have been developed to derive CPCs from ESCs. In this protocol, differentiation and purification of embryonic CPCs from both mouse and human ESCs is described. Due to the difficulty of using cell surface markers to isolate embryonic CPCs, ESCs are engineered with fluorescent reporters activated by CPC-specific cre recombinase expression. Thus, CPCs can be enriched by fluorescence-activated cell sorting (FACS). This protocol illustrates procedures to form embryoid bodies (EBs) from ESCs for CPC specification and enrichment. The isolated CPCs can be subsequently cultured for cardiac lineage differentiation and other biological assays. This protocol is optimized for robust and efficient derivation of CPCs from both mouse and human ESCs.
Developmental Biology, Issue 95, embryonic stem cells, embryoid bodies, cardiac progenitor cells, cardiac differentiation, FACS-sorting, fluorescent reporter
An Optogenetic Approach for Assessing Formation of Neuronal Connections in a Co-culture System
Institutions: Duke-NUS Graduate Medical School, Nanyang Technological University.
Here we describe a protocol to generate a co-culture consisting of 2 different neuronal populations. Induced pluripotent stem cells (iPSCs) are reprogrammed from human fibroblasts using episomal vectors. Colonies of iPSCs can be observed 30 days after initiation of fibroblast reprogramming. Pluripotent colonies are manually picked and grown in neural induction medium to permit differentiation into neural progenitor cells (NPCs). iPSCs rapidly convert into neuroepithelial cells within 1 week and retain the capability to self-renew when maintained at a high culture density. Primary mouse NPCs are differentiated into astrocytes by exposure to a serum-containing medium for 7 days and form a monolayer upon which embryonic day 18 (E18) rat cortical neurons (transfected with channelrhodopsin-2 (ChR2)) are added. Human NPCs tagged with the fluorescent protein, tandem dimer Tomato (tdTomato), are then seeded onto the astrocyte/cortical neuron culture the following day and allowed to differentiate for 28 to 35 days. We demonstrate that this system forms synaptic connections between iPSC-derived neurons and cortical neurons, evident from an increase in the frequency of synaptic currents upon photostimulation of the cortical neurons. This co-culture system provides a novel platform for evaluating the ability of iPSC-derived neurons to create synaptic connections with other neuronal populations.
Developmental Biology, Issue 96, Neuroscience, Channelrhodopsin-2, Co-culture, Neurons, Astrocytes, induced Pluripotent Stem Cells, Neural progenitors, Differentiation, Cell culture, Cortex
Generation of Murine Cardiac Pacemaker Cell Aggregates Based on ES-Cell-Programming in Combination with Myh6-Promoter-Selection
Institutions: University of Rostock.
Treatment of the “sick sinus syndrome” is based on artificial pacemakers. These bear hazards such as battery failure and infections. Moreover, they lack hormone responsiveness and the overall procedure is cost-intensive. “Biological pacemakers” generated from PSCs may become an alternative, yet the typical content of pacemaker cells in Embryoid Bodies (EBs) is extremely low. The described protocol combines “forward programming” of murine PSCs via
the sinus node inducer TBX3 with Myh6-promoter based antibiotic selection. This yields cardiomyocyte aggregates consistent of >80% physiologically functional pacemaker cells. These “induced-sinoatrial-bodies” (“iSABs”) are spontaneously contracting at yet unreached frequencies (400-500 bpm) corresponding to nodal cells isolated from mouse hearts and are able to pace murine myocardium ex vivo
. Using the described protocol highly pure sinus nodal single cells can be generated which e.g.
can be used for in vitro
drug testing. Furthermore, the iSABs generated according to this protocol may become a crucial step towards heart tissue engineering.
Developmental Biology, Issue 96, murine, pluripotent stem cells (PSC), sick sinus syndrome, iSABs, induced sino-atrial bodies, cardiomyocytes, pacemaker
Transfection, Selection, and Colony-picking of Human Induced Pluripotent Stem Cells TALEN-targeted with a GFP Gene into the AAVS1 Safe Harbor
Institutions: National Institutes of Health, Q Therapeutics.
Targeted transgene addition can provide persistent gene expression while circumventing the gene silencing and insertional mutagenesis caused by viral vector mediated random integration. This protocol describes a universal and efficient transgene targeted addition platform in human iPSCs based on utilization of validated open-source TALENs and a gene-trap-like donor to deliver transgenes into a safe harbor locus. Importantly, effective gene editing is rate-limited by the delivery efficiency of gene editing vectors. Therefore, this protocol first focuses on preparation of iPSCs for transfection to achieve high nuclear delivery efficiency. When iPSCs are dissociated into single cells using a gentle-cell dissociation reagent and transfected using an optimized program, >50% cells can be induced to take up the large gene editing vectors. Because the AAVS1 locus is located in the intron of an active gene (PPP1R12C
), a splicing acceptor (SA)-linked puromycin resistant gene (PAC) was used to select targeted iPSCs while excluding random integration-only and untransfected cells. This strategy greatly increases the chance of obtaining targeted clones, and can be used in other active gene targeting experiments as well. Two weeks after puromycin selection at the dose adjusted for the specific iPSC line, clones are ready to be picked by manual dissection of large, isolated colonies into smaller pieces that are transferred to fresh medium in a smaller well for further expansion and genetic and functional screening. One can follow this protocol to readily obtain multiple GFP reporter iPSC lines that are useful for in vivo
and in vitro
imaging and cell isolation.
Developmental Biology, Issue 96, induced pluripotent stem cell, gene editing, AAVS1, TALEN, GFP
Derivation of Highly Purified Cardiomyocytes from Human Induced Pluripotent Stem Cells Using Small Molecule-modulated Differentiation and Subsequent Glucose Starvation
Institutions: Stanford University School of Medicine, Stanford University School of Medicine.
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have become an important cell source to address the lack of primary cardiomyocytes available for basic research and translational applications. To differentiate hiPSCs into cardiomyocytes, various protocols including embryoid body (EB)-based differentiation and growth factor induction have been developed. However, these protocols are inefficient and highly variable in their ability to generate purified cardiomyocytes. Recently, a small molecule-based protocol utilizing modulation of Wnt/β-Catenin signaling was shown to promote cardiac differentiation with high efficiency. With this protocol, greater than 50%-60% of differentiated cells were cardiac troponin-positive cardiomyocytes were consistently observed. To further increase cardiomyocyte purity, the differentiated cells were subjected to glucose starvation to specifically eliminate non-cardiomyocytes based on the metabolic differences between cardiomyocytes and non-cardiomyocytes. Using this selection strategy, we consistently obtained a greater than 30% increase in the ratio of cardiomyocytes to non-cardiomyocytes in a population of differentiated cells. These highly purified cardiomyocytes should enhance the reliability of results from human iPSC-based in vitro
disease modeling studies and drug screening assays.
Developmental Biology, Issue 97, Human induced pluripotent stem cells, cardiac differentiation, small molecule compounds, cardiomyocytes, glucose starvation
Analyzing the Functions of Mast Cells In Vivo Using 'Mast Cell Knock-in' Mice
Institutions: Stanford University School of Medicine, Stanford University School of Medicine.
Mast cells (MCs) are hematopoietic cells which reside in various tissues, and are especially abundant at sites exposed to the external environment, such as skin, airways and gastrointestinal tract. Best known for their detrimental role in IgE-dependent allergic reactions, MCs have also emerged as important players in host defense against venom and invading bacteria and parasites. MC phenotype and function can be influenced by microenvironmental factors that may differ according to anatomic location and/or based on the type or stage of development of immune responses. For this reason, we and others have favored in vivo
approaches over in vitro
methods to gain insight into MC functions. Here, we describe methods for the generation of mouse bone marrow-derived cultured MCs (BMCMCs), their adoptive transfer into genetically MC-deficient mice, and the analysis of the numbers and distribution of adoptively transferred MCs at different anatomical sites. This method, named the ‘mast cell knock-in’
approach, has been extensively used over the past 30 years to assess the functions of MCs and MC-derived products in vivo
. We discuss the advantages and limitations of this method, in light of alternative approaches that have been developed in recent years.
Immunology, Issue 99, c-kit, stem cell factor, FcεRI, immunoglobulin E, mouse model, adoptive transfer, immunology, allergy
Scalable 96-well Plate Based iPSC Culture and Production Using a Robotic Liquid Handling System
Institutions: InvivoSciences, Inc., Gilson, Inc..
Continued advancement in pluripotent stem cell culture is closing the gap between bench and bedside for using these cells in regenerative medicine, drug discovery and safety testing. In order to produce stem cell derived biopharmaceutics and cells for tissue engineering and transplantation, a cost-effective cell-manufacturing technology is essential. Maintenance of pluripotency and stable performance of cells in downstream applications (e.g.
, cell differentiation) over time is paramount to large scale cell production. Yet that can be difficult to achieve especially if cells are cultured manually where the operator can introduce significant variability as well as be prohibitively expensive to scale-up. To enable high-throughput, large-scale stem cell production and remove operator influence novel stem cell culture protocols using a bench-top multi-channel liquid handling robot were developed that require minimal technician involvement or experience. With these protocols human induced pluripotent stem cells (iPSCs) were cultured in feeder-free conditions directly from a frozen stock and maintained in 96-well plates. Depending on cell line and desired scale-up rate, the operator can easily determine when to passage based on a series of images showing the optimal colony densities for splitting. Then the necessary reagents are prepared to perform a colony split to new plates without a centrifugation step. After 20 passages (~3 months), two iPSC lines maintained stable karyotypes, expressed stem cell markers, and differentiated into cardiomyocytes with high efficiency. The system can perform subsequent high-throughput screening of new differentiation protocols or genetic manipulation designed for 96-well plates. This technology will reduce the labor and technical burden to produce large numbers of identical stem cells for a myriad of applications.
Developmental Biology, Issue 99, iPSC, high-throughput, robotic, liquid-handling, scalable, stem cell, automated stem cell culture, 96-well
Isolation and Functional Characterization of Human Ventricular Cardiomyocytes from Fresh Surgical Samples
Institutions: University of Florence, University of Florence.
Cardiomyocytes from diseased hearts are subjected to complex remodeling processes involving changes in cell structure, excitation contraction coupling and membrane ion currents. Those changes are likely to be responsible for the increased arrhythmogenic risk and the contractile alterations leading to systolic and diastolic dysfunction in cardiac patients. However, most information on the alterations of myocyte function in cardiac diseases has come from animal models.
Here we describe and validate a protocol to isolate viable myocytes from small surgical samples of ventricular myocardium from patients undergoing cardiac surgery operations. The protocol is described in detail. Electrophysiological and intracellular calcium measurements are reported to demonstrate the feasibility of a number of single cell measurements in human ventricular cardiomyocytes obtained with this method.
The protocol reported here can be useful for future investigations of the cellular and molecular basis of functional alterations of the human heart in the presence of different cardiac diseases. Further, this method can be used to identify novel therapeutic targets at cellular level and to test the effectiveness of new compounds on human cardiomyocytes, with direct translational value.
Medicine, Issue 86, cardiology, cardiac cells, electrophysiology, excitation-contraction coupling, action potential, calcium, myocardium, hypertrophic cardiomyopathy, cardiac patients, cardiac disease
Intramyocardial Cell Delivery: Observations in Murine Hearts
Institutions: Imperial College London, Imperial College London, Monash University.
Previous studies showed that cell delivery promotes cardiac function amelioration by release of cytokines and factors that increase cardiac tissue revascularization and cell survival. In addition, further observations revealed that specific stem cells, such as cardiac stem cells, mesenchymal stem cells and cardiospheres have the ability to integrate within the surrounding myocardium by differentiating into cardiomyocytes, smooth muscle cells and endothelial cells.
Here, we present the materials and methods to reliably deliver noncontractile cells into the left ventricular wall of immunodepleted mice. The salient steps of this microsurgical procedure involve anesthesia and analgesia injection, intratracheal intubation, incision to open the chest and expose the heart and delivery of cells by a sterile 30-gauge needle and a precision microliter syringe.
Tissue processing consisting of heart harvesting, embedding, sectioning and histological staining showed that intramyocardial cell injection produced a small damage in the epicardial area, as well as in the ventricular wall. Noncontractile cells were retained into the myocardial wall of immunocompromised mice and were surrounded by a layer of fibrotic tissue, likely to protect from cardiac pressure and mechanical load.
Medicine, Issue 83, intramyocardial cell injection, heart, grafting, cell therapy, stem cells, fibrotic tissue
In vitro Differentiation of Mouse Embryonic Stem (mES) Cells Using the Hanging Drop Method
Institutions: Stanford University .
Stem cells have the remarkable potential to develop into many different cell types. When a stem cell divides, each new cell has the potential to either remain a stem cell or become another type of cell with a more specialized function, This promising of science is leading scientists to investigate the possibility of cell-based therapies to treat disease.
When culture in suspension without antidifferentiation factors, embryonic stem cells spontaneously differentiate and form three-dimensional multicellular aggregates. These cell aggregates are called embryoid bodies(EB). Hanging drop culture is a widely used EB formation induction method. The rounded bottom of hanging drop allows the aggregation of ES cells which can provide mES cells a good environment for forming EBs. The number of ES cells aggregatied in a hanging drop can be controlled by varying the number of cells in the initial cell suspension to be hung as a drop from the lid of Petri dish. Using this method we can reproducibly form homogeneous EBs from a predetermined number of ES cells.
Cell Biology, Issue 17, Embryonic stem cell, hanging drop, embryoid body, cardiomyocyte
Use of Human Perivascular Stem Cells for Bone Regeneration
Institutions: School of Dentistry, UCLA, UCLA, UCLA, University of Edinburgh .
Human perivascular stem cells (PSCs) can be isolated in sufficient numbers from multiple tissues for purposes of skeletal tissue engineering1-3
. PSCs are a FACS-sorted population of 'pericytes' (CD146+CD34-CD45-) and 'adventitial cells' (CD146-CD34+CD45-), each of which we have previously reported to have properties of mesenchymal stem cells. PSCs, like MSCs, are able to undergo osteogenic differentiation, as well as secrete pro-osteogenic cytokines1,2
. In the present protocol, we demonstrate the osteogenicity of PSCs in several animal models including a muscle pouch implantation in SCID (severe combined immunodeficient) mice, a SCID mouse calvarial defect and a femoral segmental defect (FSD) in athymic rats. The thigh muscle pouch model is used to assess ectopic bone formation. Calvarial defects are centered on the parietal bone and are standardly 4 mm in diameter (critically sized)8
. FSDs are bicortical and are stabilized with a polyethylene bar and K-wires4
. The FSD described is also a critical size defect, which does not significantly heal on its own4
. In contrast, if stem cells or growth factors are added to the defect site, significant bone regeneration can be appreciated. The overall goal of PSC xenografting is to demonstrate the osteogenic capability of this cell type in both ectopic and orthotopic bone regeneration models.
Bioengineering, Issue 63, Biomedical Engineering, Stem Cell Biology, Pericyte, Stem Cell, Bone Defect, Tissue Engineering, Osteogenesis, femoral defect, calvarial defect
Teratoma Generation in the Testis Capsule
Institutions: Scripps Research Institute, Scripps Research Institute , University of California.
Pluripotent stem cells (PSCs) have the unique characteristic that they can differentiate into cells from all three germ layers. This makes them a potentially valuable tool for the treatment of many different diseases. With the advent of induced pluripotent stem cells (iPSCs) and continuing research with human embryonic stem cells (hESCs) there is a need for assays that can demonstrate that a particular cell line is pluripotent. Germline transmission has been the gold standard for demonstrating the pluripotence of mouse embryonic stem cell (mESC) lines1,2,3
. Using this assay, researchers can show that a mESC line can make all cell types in the embryo including germ cells4
. With the generation of human ESC lines5,6
, the appropriate assay to prove pluripotence of these cells was unclear since human ESCs cannot be tested for germline transmission. As a surrogate, the teratoma assay is currently used to demonstrate the pluripotency of human pluripotent stem cells (hPSCs)7,8,9
. Though this assay has recently come under scrutiny and new technologies are being actively explored, the teratoma assay is the current gold standard7
. In this assay, the cells in question are injected into an immune compromised mouse. If the cells are pluripotent, a teratoma will eventually develop and sections of the tumor will show tissues from all 3 germ layers10
. In the teratoma assay, hPSCs can be injected into different areas of the mouse. The most common injection sites include the testis capsule, the kidney capsule, the liver; or into the leg either subcutaneously or intramuscularly11
. Here we describe a robust protocol for the generation of teratomas from hPSCs using the testis capsule as the site for tumor growth.
Medicine, Issue 57, stem cells, pluripotent stem cells, hPSCs, teratoma assay, animal model, mouse testis capsule
Efficient Derivation of Human Cardiac Precursors and Cardiomyocytes from Pluripotent Human Embryonic Stem Cells with Small Molecule Induction
Institutions: San Diego Regenerative Medicine Institute, Xcelthera, Harvard Medical School, VA Boston Healthcare System, Sanford-Burnham Medical Research Institute, La Jolla IVF.
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.
Developmental Biology, Issue 57, human embryonic stem cell, human, cardiac progenitor, cardiomyocytes, human pluripotent cell, cardiac differentiation, small molecule induction, cell culture, cell therapy
Isolation of Cardiomyocyte Nuclei from Post-mortem Tissue
Institutions: University of Lund, University of Lund.
Identification of cardiomyocyte nuclei has been challenging in tissue sections as most strategies rely only on cytoplasmic marker proteins1
. Rare events in cardiac myocytes such as proliferation and apoptosis require an accurate identification of cardiac myocyte nuclei to analyze cellular renewal in homeostasis and in pathological conditions2
. Here, we provide a method to isolate cardiomyocyte nuclei from post mortem tissue by density sedimentation and immunolabeling with antibodies against pericentriolar material 1 (PCM-1) and subsequent flow cytometry sorting. This strategy allows a high throughput analysis and isolation with the advantage of working equally well on fresh tissue and frozen archival material. This makes it possible to study material already collected in biobanks. This technique is applicable and tested in a wide range of species and suitable for multiple downstream applications such as carbon-14 dating3
, cell-cycle analysis4
, visualization of thymidine analogues (e.g. BrdU and IdU)4
, transcriptome and epigenetic analysis.
Medicine, Issue 65, Stem Cell Biology, Cardiology, Physiology, Tissue Engineering, cardiomyocyte, post mortem, nuclei isolation, flow cytometry, pericentriolar material 1, PCM-1
Isolation and Culture of Neonatal Mouse Cardiomyocytes
Institutions: King’s College London, University of California San Diego .
Cultured neonatal cardiomyocytes have long been used to study myofibrillogenesis and myofibrillar functions. Cultured cardiomyocytes allow for easy investigation and manipulation of biochemical pathways, and their effect on the biomechanical properties of spontaneously beating cardiomyocytes.
The following 2-day protocol describes the isolation and culture of neonatal mouse cardiomyocytes. We show how to easily dissect hearts from neonates, dissociate the cardiac tissue and enrich cardiomyocytes from the cardiac cell-population. We discuss the usage of different enzyme mixes for cell-dissociation, and their effects on cell-viability. The isolated cardiomyocytes can be subsequently used for a variety of morphological, electrophysiological, biochemical, cell-biological or biomechanical assays. We optimized the protocol for robustness and reproducibility, by using only commercially available solutions and enzyme mixes that show little lot-to-lot variability. We also address common problems associated with the isolation and culture of cardiomyocytes, and offer a variety of options for the optimization of isolation and culture conditions.
Cellular Biology, Issue 79, Biomedical Engineering, Bioengineering, Molecular Biology, Cell Culture Techniques, Primary Cell Culture, Cell Culture Techniques, Primary Cell Culture, Cell Culture Techniques, Primary Cell Culture, Cell Culture Techniques, Disease Models, Animal, Models, Cardiovascular, Cell Biology, neonatal mouse, cardiomyocytes, isolation, culture, primary cells, NMC, heart cells, animal model
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
Generation of Human Cardiomyocytes: A Differentiation Protocol from Feeder-free Human Induced Pluripotent Stem Cells
Institutions: Humanitas Clinical and Research Center, Italy, National Research Council (CNR).
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.
Stem Cell Biology, Issue 76, Developmental Biology, Molecular Biology, Cellular Biology, Medicine, Bioengineering, Biomedical Engineering, Genetics, Cardiology, Stem Cell Research, Cardiovascular Diseases, Human cardiomyocytes, iPS cells, induced pluripotent stem cells, stem cells, cardiac differentiation, disease modeling, embryoid bodies, cell lines, cell culture
Transplantation of Induced Pluripotent Stem Cell-derived Mesoangioblast-like Myogenic Progenitors in Mouse Models of Muscle Regeneration
Institutions: University College London, San Raffaele Hospital.
Patient-derived iPSCs could be an invaluable source of cells for future autologous cell therapy protocols. iPSC-derived myogenic stem/progenitor cells similar to pericyte-derived mesoangioblasts (iPSC-derived mesoangioblast-like stem/progenitor cells: IDEMs) can be established from iPSCs generated from patients affected by different forms of muscular dystrophy. Patient-specific IDEMs can be genetically corrected with different strategies (e.g.
lentiviral vectors, human artificial chromosomes) and enhanced in their myogenic differentiation potential upon overexpression of the myogenesis regulator MyoD. This myogenic potential is then assessed in vitro
with specific differentiation assays and analyzed by immunofluorescence. The regenerative potential of IDEMs is further evaluated in vivo
, upon intramuscular and intra-arterial transplantation in two representative mouse models displaying acute and chronic muscle regeneration. The contribution of IDEMs to the host skeletal muscle is then confirmed by different functional tests in transplanted mice. In particular, the amelioration of the motor capacity of the animals is studied with treadmill tests. Cell engraftment and differentiation are then assessed by a number of histological and immunofluorescence assays on transplanted muscles. Overall, this paper describes the assays and tools currently utilized to evaluate the differentiation capacity of IDEMs, focusing on the transplantation methods and subsequent outcome measures to analyze the efficacy of cell transplantation.
Bioengineering, Issue 83, Skeletal Muscle, Muscle Cells, Muscle Fibers, Skeletal, Pericytes, Stem Cells, Induced Pluripotent Stem Cells (iPSCs), Muscular Dystrophies, Cell Differentiation, animal models, muscle stem/progenitor cells, mesoangioblasts, muscle regeneration, iPSC-derived mesoangioblasts (IDEMs)
Generation of Induced Pluripotent Stem Cells from Frozen Buffy Coats using Non-integrating Episomal Plasmids
Institutions: European Academy Bozen/Bolzano (EURAC), Fondazione IRCCS Ca´ Granda, Ospedale Maggiore Policlinico, Sanford-Burnham Medical Research Institute.
Somatic cells can be reprogrammed into induced pluripotent stem cells (iPSCs) by forcing the expression of four transcription factors (Oct-4, Sox-2, Klf-4, and c-Myc), typically expressed by human embryonic stem cells (hESCs). Due to their similarity with hESCs, iPSCs have become an important tool for potential patient-specific regenerative medicine, avoiding ethical issues associated with hESCs. In order to obtain cells suitable for clinical application, transgene-free iPSCs need to be generated to avoid transgene reactivation, altered gene expression and misguided differentiation. Moreover, a highly efficient and inexpensive reprogramming method is necessary to derive sufficient iPSCs for therapeutic purposes. Given this need, an efficient non-integrating episomal plasmid approach is the preferable choice for iPSC derivation. Currently the most common cell type used for reprogramming purposes are fibroblasts, the isolation of which requires tissue biopsy, an invasive surgical procedure for the patient. Therefore, human peripheral blood represents the most accessible and least invasive tissue for iPSC generation.
In this study, a cost-effective and viral-free protocol using non-integrating episomal plasmids is reported for the generation of iPSCs from human peripheral blood mononuclear cells (PBMNCs) obtained from frozen buffy coats after whole blood centrifugation and without density gradient separation.
Developmental Biology, Issue 100, Stem cell biology, cellular biology, molecular biology, induced pluripotent stem cells, peripheral blood mononuclear cells, reprogramming, episomal plasmids.