ABSTRACT
The motor symptoms of Parkinson's disease (PD) are caused by the progressive loss of dopamine neurons from the substantia nigra. There are currently no treatments that can slow or reverse the neurodegeneration. To restore the lost neurons, international groups have initiated clinical trials using human embryonic or induced pluripotent stem cells (PSCs) to derive dopamine neuron precursors that are used as transplants to replace the lost neurons. Proof of principle experiments in the 1980s and 1990s showed that grafts of fetal ventral mesencephalon, which contains the precursors of the substantial nigra, could, under rare circumstances, reverse symptoms of the disease. Improvements in PSC technology and genomics have inspired researchers to design clinical trials using PSC-derived dopamine neuron precursors as cell replacement therapy for PD. We focus here on four such first-in-human clinical trials that have begun in the US, Europe, and Japan. We provide an overview of the sources of PSCs and the methods used to generate cells for transplantation. We discuss pros and cons of strategies for allogeneic, immune-matched, and autologous approaches and novel methods for overcoming rejection by the immune system. We consider challenges for safety and efficacy of the cells for durable engraftment, focusing on the genomics-based quality control methods to assure that the cells will not become cancerous. Finally, since clinical trials like these have never been undertaken before, we comment on the value of cooperation among rivals to contribute to advancements that will finally provide relief for the millions suffering from the symptoms of PD.
ABSTRACT
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
ABSTRACT
This report summarizes the recent activity of the International Stem Cell Banking Initiative held at Harvard Stem Cell Institute, Boston, MA, USA, on June 18, 2017. In this meeting, we aimed to find consensus on ongoing issues of quality control (QC), safety, and efficacy of human pluripotent stem cell banks and their derivative cell therapy products for the global harmonization. In particular, assays for the QC testing such as pluripotency assays test and general QC testing criteria were intensively discussed. Moreover, the recent activities of global stem cell banking centers and the regulatory bodies were briefly summarized to provide an overview on global developments and issues. Stem Cells 2019;37:1130-1135.
Subject(s)
Pluripotent Stem Cells/cytology , Stem Cells/cytology , Tissue Banks/standards , Boston , Cell- and Tissue-Based Therapy/methods , Humans , Induced Pluripotent Stem Cells/cytology , International Cooperation , Quality ControlSubject(s)
Academies and Institutes/economics , Academies and Institutes/organization & administration , Advertising/standards , Quackery/prevention & control , Stem Cell Research/economics , California , Clinical Trials as Topic/economics , Embryonic Stem Cells/cytology , Humans , Parkinson Disease/pathology , Parkinson Disease/therapy , Public Opinion , Regenerative Medicine/economics , Regenerative Medicine/organization & administration , Regenerative Medicine/standards , Stem Cell Research/ethics , United States , United States Food and Drug Administration/legislation & jurisprudenceABSTRACT
Multiple sclerosis (MS) is a central nervous system (CNS) disease characterized by chronic neuroinflammation, demyelination, and axonal damage. Infiltration of activated lymphocytes and myeloid cells are thought to be primarily responsible for white matter damage and axonopathy. Several United States Food and Drug Administration-approved therapies exist that impede activated lymphocytes from entering the CNS thereby limiting new lesion formation in patients with relapse-remitting forms of MS. However, a significant challenge within the field of MS research is to develop effective and sustained therapies that allow for axonal protection and remyelination. In recent years, there has been increasing evidence that some kinds of stem cells and their derivatives seem to be able to mute neuroinflammation as well as promote remyelination and axonal integrity. Intracranial infection of mice with the neurotropic JHM strain of mouse hepatitis virus (JHMV) results in immune-mediated demyelination and axonopathy, making this an excellent model to interrogate the therapeutic potential of stem cell derivatives in evoking remyelination. This review provides a succinct overview of our recent findings using intraspinal injection of mouse CNS neural progenitor cells and human neural precursors into JHMV-infected mice. JHMV-infected mice receiving these cells display extensive remyelination associated with axonal sparing. In addition, we discuss possible mechanisms associated with sustained clinical recovery. Developmental Dynamics 248:43-52, 2019. © 2018 Wiley Periodicals, Inc.
Subject(s)
Neurodegenerative Diseases/therapy , Remyelination , Stem Cell Transplantation/methods , Animals , Disease Models, Animal , Humans , Mice , Multiple Sclerosis/therapy , Murine hepatitis virus , Neurodegenerative Diseases/pathology , Neurodegenerative Diseases/virologyABSTRACT
Duplication of the genome in mammalian cells occurs in a defined temporal order referred to as its replication-timing (RT) program. RT changes dynamically during development, regulated in units of 400-800 kb referred to as replication domains (RDs). Changes in RT are generally coordinated with transcriptional competence and changes in subnuclear position. We generated genome-wide RT profiles for 26 distinct human cell types, including embryonic stem cell (hESC)-derived, primary cells and established cell lines representing intermediate stages of endoderm, mesoderm, ectoderm, and neural crest (NC) development. We identified clusters of RDs that replicate at unique times in each stage (RT signatures) and confirmed global consolidation of the genome into larger synchronously replicating segments during differentiation. Surprisingly, transcriptome data revealed that the well-accepted correlation between early replication and transcriptional activity was restricted to RT-constitutive genes, whereas two-thirds of the genes that switched RT during differentiation were strongly expressed when late replicating in one or more cell types. Closer inspection revealed that transcription of this class of genes was frequently restricted to the lineage in which the RT switch occurred, but was induced prior to a late-to-early RT switch and/or down-regulated after an early-to-late RT switch. Analysis of transcriptional regulatory networks showed that this class of genes contains strong regulators of genes that were only expressed when early replicating. These results provide intriguing new insight into the complex relationship between transcription and RT regulation during human development.
Subject(s)
Cell Lineage , DNA Replication Timing , Gene Expression Profiling/methods , Pluripotent Stem Cells/physiology , Cell Differentiation , Cells, Cultured , Cluster Analysis , Gene Expression Regulation, Developmental , Gene Regulatory Networks , Genome, Human , Humans , Pluripotent Stem Cells/cytologyABSTRACT
Mechanisms of initial cell fate decisions differ among species. To gain insights into lineage allocation in humans, we derived ten human embryonic stem cell lines (designated UCSFB1-10) from single blastomeres of four 8-cell embryos and one 12-cell embryo from a single couple. Compared with numerous conventional lines from blastocysts, they had unique gene expression and DNA methylation patterns that were, in part, indicative of trophoblast competence. At a transcriptional level, UCSFB lines from different embryos were often more closely related than those from the same embryo. As predicted by the transcriptomic data, immunolocalization of EOMES, T brachyury, GDF15 and active ß-catenin revealed differential expression among blastomeres of 8- to 10-cell human embryos. The UCSFB lines formed derivatives of the three germ layers and CDX2-positive progeny, from which we derived the first human trophoblast stem cell line. Our data suggest heterogeneity among early-stage blastomeres and that the UCSFB lines have unique properties, indicative of a more immature state than conventional lines.
Subject(s)
Blastomeres/cytology , Embryo Culture Techniques , Embryonic Stem Cells/cytology , Trophoblasts/cytology , Blastocyst/cytology , Cell Differentiation , Cell Line , Cell Lineage , DNA Methylation , Endoderm/metabolism , Fibroblasts/metabolism , Gene Expression Profiling , Gene Expression Regulation, Developmental , Growth Differentiation Factor 15/metabolism , Humans , Myocytes, Cardiac/cytology , Myocytes, Cardiac/metabolism , Neural Stem Cells/cytology , Oligonucleotide Array Sequence Analysis , Transcription, Genetic , Transcriptome , beta Catenin/metabolismABSTRACT
Genomic aberrations have been identified in many human pluripotent stem cell (hPSC) cultures. Commonly observed duplications in portions of chromosomes 12p and 17q have been associated with increases in genetic instability and resistance to apoptosis, respectively. However, the phenotypic consequences related to sporadic mutations have not been evaluated to date. Here, we report on the effects of a single-copy deletion of the chr17p13.1 region, a sporadic mutation that spontaneously arose independently in several subclones of a human embryonic stem cell culture. Compared to cells with two normal copies of chr17p13.1 ("wild-type"), the cells with a single-copy deletion of this region ("mutant") displayed a selective advantage when exposed to stressful conditions, and retained a higher percentage of cells expressing the pluripotency marker POU5F1/OCT4 after 2 weeks of in vitro differentiation. Knockdown of TP53, which is a gene encompassed by the deleted region, in wild-type cells mimicked the chr17p13.1 deletion phenotype. Thus, sporadic mutations in hPSCs can have phenotypic effects that may impact their utility for clinical applications. Stem Cells 2017;35:872-885.
Subject(s)
Gene Dosage , Human Embryonic Stem Cells/cytology , Human Embryonic Stem Cells/metabolism , Mutation/genetics , Tumor Suppressor Protein p53/genetics , Apoptosis/drug effects , Cell Cycle/drug effects , Cell Differentiation/drug effects , Cell Line , Cell Proliferation/drug effects , Cell Survival/drug effects , Chromosomes, Human, Pair 17/genetics , Clone Cells , DNA Damage , DNA Repair/drug effects , Etoposide/pharmacology , Gene Expression Profiling , Gene Knockdown Techniques , Human Embryonic Stem Cells/drug effects , Humans , Phenotype , RNA, Small Interfering/metabolism , Staurosporine/pharmacologyABSTRACT
The study and application of human pluripotent stem cells (hPSCs) will be enhanced by the availability of well-characterized monoclonal antibodies (mAbs) detecting cell-surface epitopes. Here, we report generation of seven new mAbs that detect cell surface proteins present on live and fixed human ES cells (hESCs) and human iPS cells (hiPSCs), confirming our previous prediction that these proteins were present on the cell surface of hPSCs. The mAbs all show a high correlation with POU5F1 (OCT4) expression and other hPSC surface markers (TRA-160 and SSEA-4) in hPSC cultures and detect rare OCT4 positive cells in differentiated cell cultures. These mAbs are immunoreactive to cell surface protein epitopes on both primed and naive state hPSCs, providing useful research tools to investigate the cellular mechanisms underlying human pluripotency and states of cellular reprogramming. In addition, we report that subsets of the seven new mAbs are also immunoreactive to human bone marrow-derived mesenchymal stem cells (MSCs), normal human breast subsets and both normal and tumorigenic colorectal cell populations. The mAbs reported here should accelerate the investigation of the nature of pluripotency, and enable development of robust cell separation and tracing technologies to enrich or deplete for hPSCs and other human stem and somatic cell types. Stem Cells 2017;35:626-640.
Subject(s)
Antibodies, Monoclonal/immunology , Membrane Proteins/immunology , Pluripotent Stem Cells/metabolism , Animals , Antigens, Surface/metabolism , Cell Culture Techniques , Cell Differentiation , Cell Self Renewal , Down-Regulation/genetics , Embryoid Bodies/cytology , Embryoid Bodies/metabolism , Flow Cytometry , Hematopoietic Stem Cells/metabolism , Humans , Membrane Proteins/metabolism , Mice , Octamer Transcription Factor-3/metabolismABSTRACT
New research suggests that common pathways are altered in many neurodevelopmental disorders including autism spectrum disorder; however, little is known about early molecular events that contribute to the pathology of these diseases. The study of monogenic, neurodevelopmental disorders with a high incidence of autistic behaviours, such as fragile X syndrome, has the potential to identify genes and pathways that are dysregulated in autism spectrum disorder as well as fragile X syndrome. In vitro generation of human disease-relevant cell types provides the ability to investigate aspects of disease that are impossible to study in patients or animal models. Differentiation of human pluripotent stem cells recapitulates development of the neocortex, an area affected in both fragile X syndrome and autism spectrum disorder. We have generated induced human pluripotent stem cells from several individuals clinically diagnosed with fragile X syndrome and autism spectrum disorder. When differentiated to dorsal forebrain cell fates, our fragile X syndrome human pluripotent stem cell lines exhibited reproducible aberrant neurogenic phenotypes. Using global gene expression and DNA methylation profiling, we have analysed the early stages of neurogenesis in fragile X syndrome human pluripotent stem cells. We discovered aberrant DNA methylation patterns at specific genomic regions in fragile X syndrome cells, and identified dysregulated gene- and network-level correlates of fragile X syndrome that are associated with developmental signalling, cell migration, and neuronal maturation. Integration of our gene expression and epigenetic analysis identified altered epigenetic-mediated transcriptional regulation of a distinct set of genes in fragile X syndrome. These fragile X syndrome-aberrant networks are significantly enriched for genes associated with autism spectrum disorder, giving support to the idea that underlying similarities exist among these neurodevelopmental diseases.
Subject(s)
Cell Differentiation/genetics , Fragile X Mental Retardation Protein/genetics , Fragile X Syndrome/pathology , Gene Expression Regulation/genetics , Models, Biological , Pluripotent Stem Cells/physiology , Animals , Autism Spectrum Disorder/genetics , Autism Spectrum Disorder/pathology , Cell Movement/genetics , Cells, Cultured , DNA Methylation/genetics , Fetus , Fragile X Syndrome/genetics , Gene Regulatory Networks , Humans , Male , Mice , Neurogenesis , Transfection , Trinucleotide Repeats/geneticsABSTRACT
Human pluripotent stem cells (hPSCs) have the potential to fundamentally change the way that we go about treating and understanding human disease. Despite this extraordinary potential, these cells also have an innate capability to form tumors in immunocompromised individuals when they are introduced in their pluripotent state. Although current therapeutic strategies involve transplantation of only differentiated hPSC derivatives, there is still a concern that transplanted cell populations could contain a small percentage of cells that are not fully differentiated. In addition, these cells have been frequently reported to acquire genetic alterations that, in some cases, are associated with certain types of human cancers. Here, we try to separate the panic from reality and rationally evaluate the true tumorigenic potential of these cells. We also discuss a recent study examining the effect of culture conditions on the genetic integrity of hPSCs. Finally, we present a set of sensible guidelines for minimizing the tumorigenic potential of hPSC-derived cells. © 2016 The Authors. Inside the Cell published by Wiley Periodicals, Inc.
Subject(s)
Cell Transformation, Neoplastic , Neoplasms/pathology , Pluripotent Stem Cells/pathology , Cell Culture Techniques , Genomic Instability , Humans , Neoplasms/genetics , Neoplasms/prevention & controlABSTRACT
Increasing evidence has demonstrated that epigenetic factors can profoundly influence gene expression and, in turn, influence resistance or susceptibility to disease. Epigenetic drugs, such as histone deacetylase (HDAC) inhibitors, are finding their way into clinical practice, although their exact mechanisms of action are unclear. To identify mechanisms associated with HDAC inhibition, we performed microarray analysis on brain and muscle samples treated with the HDAC1/3-targeting inhibitor, HDACi 4b. Pathways analyses of microarray datasets implicate DNA methylation as significantly associated with HDAC inhibition. Further assessment of DNA methylation changes elicited by HDACi 4b in human fibroblasts from normal controls and patients with Huntington's disease (HD) using the Infinium HumanMethylation450 BeadChip revealed a limited, but overlapping, subset of methylated CpG sites that were altered by HDAC inhibition in both normal and HD cells. Among the altered loci of Y chromosome-linked genes, KDM5D, which encodes Lys (K)-specific demethylase 5D, showed increased methylation at several CpG sites in both normal and HD cells, as well as in DNA isolated from sperm from drug-treated male mice. Further, we demonstrate that first filial generation (F1) offspring from drug-treated male HD transgenic mice show significantly improved HD disease phenotypes compared with F1 offspring from vehicle-treated male HD transgenic mice, in association with increased Kdm5d expression, and decreased histone H3 Lys4 (K4) (H3K4) methylation in the CNS of male offspring. Additionally, we show that overexpression of Kdm5d in mutant HD striatal cells significantly improves metabolic deficits. These findings indicate that HDAC inhibitors can elicit transgenerational effects, via cross-talk between different epigenetic mechanisms, to have an impact on disease phenotypes in a beneficial manner.
Subject(s)
DNA Methylation/genetics , Histone Deacetylase Inhibitors/therapeutic use , Histones/metabolism , Huntington Disease/drug therapy , Huntington Disease/genetics , Animals , DNA Methylation/drug effects , Disease Models, Animal , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/pathology , Genetic Loci , Histone Deacetylase Inhibitors/pharmacology , Humans , Huntington Disease/pathology , Male , Mice, Transgenic , Phenotype , Real-Time Polymerase Chain Reaction , Reproducibility of Results , Spermatozoa/drug effects , Spermatozoa/metabolismABSTRACT
The placenta is a transient organ that is necessary for proper fetal development. Its main functional component is the trophoblast, which is derived from extra-embryonic ectoderm. Little is known about early trophoblast differentiation in the human embryo, owing to lack of a proper in vitro model system. Human embryonic stem cells (hESCs) differentiate into functional trophoblast following BMP4 treatment in the presence of feeder-conditioned media; however, this model has not been widely accepted, in part owing to a lack of proof for a trophoblast progenitor population. We have previously shown that p63, a member of the p53 family of nuclear proteins, is expressed in proliferative cytotrophoblast (CTB), precursors to terminally differentiated syncytiotrophoblast (STB) in chorionic villi and extravillous trophoblast (EVT) at the implantation site. Here, we show that BMP4-treated hESCs differentiate into bona fide CTB by direct comparison with primary human placental tissues and isolated CTB through gene expression profiling. We show that, in primary CTB, p63 levels are reduced as cells differentiate into STB, and that forced expression of p63 maintains cyclin B1 and inhibits STB differentiation. We also establish that, similar to in vivo events, hESC differentiation into trophoblast is characterized by a p63(+)/KRT7(+) CTB stem cell state, followed by formation of functional KLF4(+) STB and HLA-G(+) EVT. Finally, we illustrate that downregulation of p63 by shRNA inhibits differentiation of hESCs into functional trophoblast. Taken together, our results establish that BMP4-treated hESCs are an excellent model of human trophoblast differentiation, closely mimicking the in vivo progression from p63(+) CTB stem cells to terminally differentiated trophoblast subtypes.
Subject(s)
Bone Morphogenetic Protein 4/pharmacology , Embryonic Stem Cells/cytology , Embryonic Stem Cells/drug effects , Trophoblasts/cytology , Trophoblasts/drug effects , Cell Differentiation/drug effects , Cells, Cultured , Female , Flow Cytometry , Gene Expression Profiling , Gestational Age , Humans , In Vitro Techniques , Kruppel-Like Factor 4 , Placenta/cytology , Pregnancy , Real-Time Polymerase Chain ReactionABSTRACT
Lineage conversion of one somatic cell type to another is an attractive approach for generating specific human cell types. Lineage conversion can be direct, in the absence of proliferation and multipotent progenitor generation, or indirect, by the generation of expandable multipotent progenitor states. We report the development of a reprogramming methodology in which cells transition through a plastic intermediate state, induced by brief exposure to reprogramming factors, followed by differentiation. We use this approach to convert human fibroblasts to mesodermal progenitor cells, including by non-integrative approaches. These progenitor cells demonstrated bipotent differentiation potential and could generate endothelial and smooth muscle lineages. Differentiated endothelial cells exhibited neo-angiogenesis and anastomosis in vivo. This methodology for indirect lineage conversion to angioblast-like cells adds to the armamentarium of reprogramming approaches aimed at the study and treatment of ischemic pathologies.
Subject(s)
Cell Differentiation , Cell Lineage , Cellular Reprogramming , Endothelium, Vascular/cytology , Fibroblasts/cytology , Myocytes, Smooth Muscle/cytology , Stem Cells/cytology , Animals , Biomarkers/metabolism , Blotting, Western , Cell Movement , Cell Proliferation , Cells, Cultured , Endothelium, Vascular/metabolism , Fibroblasts/metabolism , Flow Cytometry , Fluorescent Antibody Technique , Humans , Mice , Myocytes, Smooth Muscle/metabolism , Neovascularization, Physiologic , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , Stem Cells/metabolismABSTRACT
The precise, temporal order of gene expression during development is critical to ensure proper lineage commitment, cell fate determination, and ultimately, organogenesis. Epigenetic regulation of chromatin structure is fundamental to the activation or repression of genes during embryonic development. In recent years, there has been an explosion of research relating to various modes of epigenetic regulation, such as DNA methylation, post-translational histone tail modifications, noncoding RNA control of chromatin structure, and nucleosome remodeling. Technological advances in genome-wide epigenetic profiling and pluripotent stem cell differentiation have been primary drivers for elucidating the epigenetic control of cellular identity during development and nuclear reprogramming. Not only do epigenetic mechanisms regulate transcriptional states in a cell-type-specific manner but also they establish higher order genomic topology and nuclear architecture. Here, we review the epigenetic control of pluripotency and changes associated with pluripotent stem cell differentiation. We focus on DNA methylation, DNA demethylation, and common histone tail modifications. Finally, we briefly discuss epigenetic heterogeneity among pluripotent stem cell lines and the influence of epigenetic patterns on genome topology.
Subject(s)
Epigenesis, Genetic/physiology , Gene Expression Regulation, Developmental/physiology , Pluripotent Stem Cells/cytology , Acetylation , Animals , Cell Differentiation , CpG Islands , DNA (Cytosine-5-)-Methyltransferases/metabolism , DNA Methylation , Dioxygenases/metabolism , Enhancer Elements, Genetic/genetics , Enhancer Elements, Genetic/physiology , Gene Expression Regulation, Developmental/genetics , Histones/metabolism , Humans , Mice , Models, Biological , Myocytes, Cardiac/cytology , Myocytes, Cardiac/metabolism , Phosphorylation , Promoter Regions, Genetic/genetics , Promoter Regions, Genetic/physiology , Protein Processing, Post-Translational , X Chromosome Inactivation/genetics , X Chromosome Inactivation/physiologyABSTRACT
With only three living individuals left on this planet, the northern white rhinoceros (Ceratotherium simum cottoni) could be considered doomed for extinction. It might still be possible, however, to rescue the (sub)species by combining novel stem cell and assisted reproductive technologies. To discuss the various practical options available to us, we convened a multidisciplinary meeting under the name "Conservation by Cellular Technologies." The outcome of this meeting and the proposed road map that, if successfully implemented, would ultimately lead to a self-sustaining population of an extremely endangered species are outlined here. The ideas discussed here, while centered on the northern white rhinoceros, are equally applicable, after proper adjustments, to other mammals on the brink of extinction. Through implementation of these ideas we hope to establish the foundation for reversal of some of the effects of what has been termed the sixth mass extinction event in the history of Earth, and the first anthropogenic one. Zoo Biol. 35:280-292, 2016. © 2016 The Authors. Zoo Biology published by Wiley Periodicals, Inc.
Subject(s)
Conservation of Natural Resources , Endangered Species , Perissodactyla/physiology , Animals , Conservation of Natural Resources/trends , Extinction, Biological , Mammals , Species SpecificityABSTRACT
Human pluripotent stem cells (hPSCs) are known to acquire genomic changes as they proliferate and differentiate. Despite concerns that these changes will compromise the safety of hPSC-derived cell therapy, there is currently scant evidence linking the known hPSC genomic abnormalities with malignancy. For the successful use of hPSCs for clinical applications, we will need to learn to distinguish between innocuous genomic aberrations and those that may cause tumors. To minimize any effects of acquired mutations on cell therapy, we strongly recommend that cells destined for transplant be monitored throughout their preparation using a high-resolution method such as SNP genotyping.
Subject(s)
Genomic Instability/genetics , Pluripotent Stem Cells/metabolism , Translational Research, Biomedical , Carcinogenesis/genetics , Carcinogenesis/pathology , Clinical Trials as Topic , Genetic Variation , Humans , Pluripotent Stem Cells/cytologyABSTRACT
The differentiation of human pluripotent stem cells (hPSCs) to insulin-expressing beta islet-like cells is a promising in vitro model system for studying the molecular signaling pathways underlying beta cell differentiation, as well as a potential source of cells for the treatment of type 1 diabetes. MicroRNAs (miRNAs) are a class of small non-coding RNAs that regulate many biological processes, including cellular differentiation. We studied the miRNA and mRNA expression profiles of hPSCs at five stages of in vitro differentiation along the pancreatic beta cell lineage (definitive endoderm, primitive gut tube, posterior foregut, pancreatic progenitor and hormone-expressing endocrine cells) in the context of samples of primary human fetal pancreas and purified adult islet cells using microarray analysis. Bioinformatic analysis of the resulting data identified a unique miRNA signature in differentiated beta islet cells, and predicted the effects of key miRNAs on mRNA expression. Many of the predicted miRNA-mRNA interactions involved mRNAs known to play key roles in the epithelial-mesenchymal transition process and pancreatic differentiation. We validated a subset of the predictions using qRT-PCR, luciferase reporter assays and western blotting, including the known interaction between miR-200 and ZEB2 (involved in epithelial-mesenchymal transition) and the novel interaction between miR-200 and SOX17 (a key transcription factor in specification of definitive endoderm). In addition, we found that miR-30d and let-7e, two miRNAs induced during differentiation, regulated the expression of RFX6, a transcription factor that directs pancreatic islet formation. These findings suggest that precise control of target mRNA expression by miRNAs ensures proper lineage specification during pancreatic development.
Subject(s)
Homeodomain Proteins/metabolism , Insulin-Secreting Cells/metabolism , MicroRNAs/metabolism , Pluripotent Stem Cells/metabolism , Repressor Proteins/metabolism , SOXF Transcription Factors/metabolism , Cell Differentiation/genetics , Cell Differentiation/physiology , Cell Lineage , Cell- and Tissue-Based Therapy , Cells, Cultured , DNA-Binding Proteins/biosynthesis , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Diabetes Mellitus, Type 1/therapy , Epithelial-Mesenchymal Transition/physiology , Gene Expression Profiling , Gene Expression Regulation, Developmental , Homeodomain Proteins/biosynthesis , Homeodomain Proteins/genetics , Humans , MicroRNAs/genetics , Pancreas/embryology , RNA, Messenger/genetics , Regulatory Factor X Transcription Factors , Repressor Proteins/biosynthesis , Repressor Proteins/genetics , SOXF Transcription Factors/biosynthesis , SOXF Transcription Factors/genetics , Transcription Factors/biosynthesis , Transcription Factors/genetics , Transcription Factors/metabolism , Zinc Finger E-box Binding Homeobox 2ABSTRACT
OBJECTIVE: To investigate whether a histone deacetylase inhibitor (HDACi) would be effective in an in vitro model for the neurodegenerative disease Friedreich ataxia (FRDA) and to evaluate safety and surrogate markers of efficacy in a phase I clinical trial in patients. METHODS: We used a human FRDA neuronal cell model, derived from patient induced pluripotent stem cells, to determine the efficacy of a 2-aminobenzamide HDACi (109) as a modulator of FXN gene expression and chromatin histone modifications. FRDA patients were dosed in 4 cohorts, ranging from 30mg/day to 240mg/day of the formulated drug product of HDACi 109, RG2833. Patients were monitored for adverse effects as well as for increases in FXN mRNA, frataxin protein, and chromatin modification in blood cells. RESULTS: In the neuronal cell model, HDACi 109/RG2833 increases FXN mRNA levels and frataxin protein, with concomitant changes in the epigenetic state of the gene. Chromatin signatures indicate that histone H3 lysine 9 is a key residue for gene silencing through methylation and reactivation through acetylation, mediated by the HDACi. Drug treatment in FRDA patients demonstrated increased FXN mRNA and H3 lysine 9 acetylation in peripheral blood mononuclear cells. No safety issues were encountered. INTERPRETATION: Drug exposure inducing epigenetic changes in neurons in vitro is comparable to the exposure required in patients to see epigenetic changes in circulating lymphoid cells and increases in gene expression. These findings provide a proof of concept for the development of an epigenetic therapy for this fatal neurological disease.