Project description:Multiple sclerosis involves an aberrant autoimmune response and progressive failure of remyelination in the central nervous system. Prevention of neural degeneration and subsequent disability requires remyelination through the generation of new oligodendrocytes, but current treatments exclusively target the immune system. Oligodendrocyte progenitor cells are stem cells in the central nervous system and the principal source of myelinating oligodendrocytes. These cells are abundant in demyelinated regions of patients with multiple sclerosis, yet fail to differentiate, thereby representing a cellular target for pharmacological intervention. To discover therapeutic compounds for enhancing myelination from endogenous oligodendrocyte progenitor cells, we screened a library of bioactive small molecules on mouse pluripotent epiblast stem-cell-derived oligodendrocyte progenitor cells. Here we show seven drugs function at nanomolar doses selectively to enhance the generation of mature oligodendrocytes from progenitor cells in vitro. Two drugs, miconazole and clobetasol, are effective in promoting precocious myelination in organotypic cerebellar slice cultures, and in vivo in early postnatal mouse pups. Systemic delivery of each of the two drugs significantly increases the number of new oligodendrocytes and enhances remyelination in a lysolecithin-induced mouse model of focal demyelination. Administering each of the two drugs at the peak of disease in an experimental autoimmune encephalomyelitis mouse model of chronic progressive multiple sclerosis results in striking reversal of disease severity. Immune response assays show that miconazole functions directly as a remyelinating drug with no effect on the immune system, whereas clobetasol is a potent immunosuppressant as well as a remyelinating agent. Mechanistic studies show that miconazole and clobetasol function in oligodendrocyte progenitor cells through mitogen-activated protein kinase and glucocorticoid receptor signalling, respectively. Furthermore, both drugs enhance the generation of human oligodendrocytes from human oligodendrocyte progenitor cells in vitro. Collectively, our results provide a rationale for testing miconazole and clobetasol, or structurally modified derivatives, to enhance remyelination in patients. RNA sequencing of oligodendrocyte progenitor cells treated with vehicle, miconazole or clobetasol for 0, 2, 6, or 12 hours. Cells were plated 1.5 hours prior to addition of drug.
Project description:Stem cell biology has garnered much attention due to its potential to impact human health through disease modeling and cell replacement therapy. This is especially pertinent to myelin-related disorders such as multiple sclerosis and leukodystrophies where restoration of normal oligodendrocyte function could provide an effective treatment. Progress in myelin repair has been constrained by the difficulty in generating pure populations of oligodendrocyte progenitor cells (OPCs) in sufficient quantities. Pluripotent stem cells theoretically provide an unlimited source of OPCs but significant advances are currently hindered by heterogeneous differentiation strategies that lack reproducibility. Here we provide a platform for the directed differentiation of pluripotent mouse epiblast stem cells (EpiSCs) through a defined series of developmental transitions into a pure population of highly expandable OPCs in ten days. These OPCs robustly differentiate into myelinating oligodendrocytes both in vitro and in vivo. Our results demonstrate that pluripotent stem cells can provide a pure population of clinically-relevant, myelinogenic oligodendrocytes and offer a tractable platform for defining the molecular regulation of oligodendrocyte development, drug screening, and potential cell-based remyelinating therapies. 6 total samples were analyzed. Pluripotent epiblast stem cells (EpiSCs) were differentiated to patterned neural rosettes, oligodendrocyte progenitor cells (OPCs), and oligodendrocytes. OPCs and oligodedrocytes were analyzed at two separate passages (3 and 11).
Project description:Multiple sclerosis involves an aberrant autoimmune response and progressive failure of remyelination in the central nervous system. Prevention of neural degeneration and subsequent disability requires remyelination through the generation of new oligodendrocytes, but current treatments exclusively target the immune system. Oligodendrocyte progenitor cells are stem cells in the central nervous system and the principal source of myelinating oligodendrocytes. These cells are abundant in demyelinated regions of patients with multiple sclerosis, yet fail to differentiate, thereby representing a cellular target for pharmacological intervention. To discover therapeutic compounds for enhancing myelination from endogenous oligodendrocyte progenitor cells, we screened a library of bioactive small molecules on mouse pluripotent epiblast stem-cell-derived oligodendrocyte progenitor cells. Here we show seven drugs function at nanomolar doses selectively to enhance the generation of mature oligodendrocytes from progenitor cells in vitro. Two drugs, miconazole and clobetasol, are effective in promoting precocious myelination in organotypic cerebellar slice cultures, and in vivo in early postnatal mouse pups. Systemic delivery of each of the two drugs significantly increases the number of new oligodendrocytes and enhances remyelination in a lysolecithin-induced mouse model of focal demyelination. Administering each of the two drugs at the peak of disease in an experimental autoimmune encephalomyelitis mouse model of chronic progressive multiple sclerosis results in striking reversal of disease severity. Immune response assays show that miconazole functions directly as a remyelinating drug with no effect on the immune system, whereas clobetasol is a potent immunosuppressant as well as a remyelinating agent. Mechanistic studies show that miconazole and clobetasol function in oligodendrocyte progenitor cells through mitogen-activated protein kinase and glucocorticoid receptor signalling, respectively. Furthermore, both drugs enhance the generation of human oligodendrocytes from human oligodendrocyte progenitor cells in vitro. Collectively, our results provide a rationale for testing miconazole and clobetasol, or structurally modified derivatives, to enhance remyelination in patients.
Project description:The generation of properly functioning gametes in vitro, a key goal in developmental/reproductive biology, requires multi-step reconstitutions of complex germ cell development. Based on the logic of primordial germ cell (PGC)-specification, we demonstrate here the generation of PGC-like cells (PGCLCs) in mice with robust capacity for spermatogenesis from embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) through epiblast-like cells (EpiLCs), a cellular state highly similar to pre-gastrulating epiblasts, but distinct from epiblast stem cells (EpiSCs). The global transcription profiles, epigenetic reprogramming, and cellular dynamics during PGCLC induction from EpiLCs are a meticulous capture of those associated with PGC specification from the epiblasts. Furthermore, we identify Integrin-beta 3 and SSEA1 as markers that purify PGCLCs with spermatogenic capacity free from tumorigenic undifferentiated cells. With the reconstitution of PGC specification pathway from the naive inner cell mass state, our study defines a paradigm for the essential step of in vitro gametogenesis. We performed this analysis to reveal the characters of the cells that we created in this study, epiblast-like cells (EpiLCs) and primordial germ cells-like cells (PGCLCs). Because EpiLCs were induced from embryonic stem cells (ESCs), and equivalent to pre-gastrulating epiblast (embryonic day [E] 5.5-6.0) in vivo (embryo), ESCs and epiblast were included in this analysis. Epiblast stem cells (EpiSCs) are a culture cell type derived from epiblast, and were also included. PGCLCs were supposed to be equivalent to E9.5 PGCs based on reporter fluorescent transgene expressions and epigenetic properties, and therefore E9.5 PGCs were also inckuded in this analysis. Because epiblast and E9.5 PGCs are of a small number of cells in embryos (a few hundred to thousand cells), cDNAs were amplified with a quantitative global PCR method (Kurimoto et al., 2006, Nucleic Acids Research) for microarray analyses. We took two biological replicate for each cell type.
Project description:Many studies have already shown the reprogramming of somatic cells into other cell types such as neural stem cells, blood progenitor cells, and hepatocytes by inducing combinations of transcription factors. One of the recent development in cellular reprogramming is the direct reprogramming, that can change cell fate towards different lineages. This strategy provides an alternative to the use of pluripotent stem cells ruling out the concerns of tumorigenicity caused by undifferentiated cell populations. Here, we generated induced oligodendrocyte progenitor cells (iOPCs) from mouse fibroblasts by direct reprogramming. The generated iOPCs are homogenous, self-renewing, and multipotent. Once differentiated, the somatic stem cells exhibit morphological and molecular characteristics of oligodendrocyte progenitor cells (OPCs). Thus, we demonstrated that terminally differentiated somatic cells can be converted into functional iOPCs by induction of transcription factors offering a new strategies to cure myelin disorders. To identify the global gene expression profiles of iOPCs, we analyzed total 6 samples.