Multiple layers of molecular controls modulate self-renewal and neuronal lineage specification of embryonic stem cells

Laboratory of Genetics, Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
Human Molecular Genetics (Impact Factor: 6.39). 04/2008; 17(R1):R67-75. DOI: 10.1093/hmg/ddn065
Source: PubMed


Elucidating the molecular changes that arise during neural differentiation and fate specification is crucial for building
accurate in vitro models of neurodegenerative diseases using human embryonic stem cells (hESCs). Here we review the importance of hESCs and
derived progenitors in treating and modeling neurological diseases, and summarize the current efforts for the differentiation
of hESCs into neural progenitors and defined neurons. We recapitulate the recent findings and discuss open questions on aspects
of molecular control of gene expression by chromatin modification and methylation, posttranscriptional regulation by alternative
splicing and the action of microRNAs, and protein modification. An integrative view of the different levels will hopefully
provide much needed insight into understanding stem cell biology.

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Available from: Maria C N Marchetto, Sep 15, 2014
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    • "Alternatively, hiPSCs may be grown in suspension to form embryoid bodies. Within these heterogeneous cell populations, neural rosettes are formed from which neural cells may be separated from other cell types.39, 40 Newer alternative strategies for feeder-free, directed differentiation to NSCs utilizing chemical inhibitors and purified protein activators of specific signaling pathways important in fate determination have also been developed.41, "
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    ABSTRACT: Human-induced pluripotent stem cells (hiPSCs) derived from somatic cells of patients have opened possibilities for in vitro modeling of the physiology of neural (and other) cells in psychiatric disease states. Issues in early stages of technology development include (1) establishing a library of cells from adequately phenotyped patients, (2) streamlining laborious, costly hiPSC derivation and characterization, (3) assessing whether mutations or other alterations introduced by reprogramming confound interpretation, (4) developing efficient differentiation strategies to relevant cell types, (5) identifying discernible cellular phenotypes meaningful for cyclic, stress induced or relapsing-remitting diseases, (6) converting phenotypes to screening assays suitable for genome-wide mechanistic studies or large collection compound testing and (7) controlling for variability in relation to disease specificity amidst low sample numbers. Coordination of material for reprogramming from patients well-characterized clinically, genetically and with neuroimaging are beginning, and initial studies have begun to identify cellular phenotypes. Finally, several psychiatric drugs have been found to alter reprogramming efficiency in vitro, suggesting further complexity in applying hiPSCs to psychiatric diseases or that some drugs influence neural differentiation moreso than generally recognized. Despite these challenges, studies utilizing hiPSCs may eventually serve to fill essential niches in the translational pipeline for the discovery of new therapeutics.
    Full-text · Article · Nov 2013
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    • "The biological importance of microRNA-mediated regulation is typically associated with a highly repressive MRE. Comparisons of microRNA–mediated repression in different mRNA isoforms has been successfully used to associate MRE sites with functions in many studies, such as the prediction of target mRNAs [37-41], the influence of intron retention on human mRNA [42], cellular proliferation and differentiation [12,43], and cancer [44]. The effect of fine-tuning at the splicing level would be negligible if the associated MREs are not highly repressive. "
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    ABSTRACT: MicroRNAs are very small non-coding RNAs that interact with microRNA recognition elements (MREs) on their target messenger RNAs. Varying the concentration of a given microRNA may influence the expression of many target proteins. Yet, the expression of a specific target protein can be fine-tuned by alternative cleavage and polyadenylation to the corresponding mRNA. This study showed that alternative splicing of mRNA is a fine-tuning mechanism in the cellular regulatory network. The splicing-regulated MREs are often highly repressive MREs. This phenomenon was observed not only in the hsa-miR-148a-regulated DNMT3B gene, but also in many target genes regulated by hsa-miR-124, hsa-miR-1, and hsa-miR-181a. When a gene contains multiple MREs in transcripts, such as the VEGF gene, the splicing-regulated MREs are again the highly repressive MREs. Approximately one-third of the analysable human MREs in MiRTarBase and TarBase can potentially perform the splicing-regulated fine-tuning. Interestingly, the high (+30%) repression ratios observed in most of these splicing-regulated MREs indicate associations with functions. For example, the MRE-free transcripts of many oncogenes, such as N-RAS and others may escape microRNA-mediated suppression in cancer tissues. This fine-tuning mechanism revealed associations with highly repressive MRE. Since high-repression MREs are involved in many important biological phenomena, the described association implies that splicing-regulated MREs are functional. A possible application of this observed association is in distinguishing functionally relevant MREs from predicted MREs.
    Full-text · Article · Jul 2013 · BMC Genomics
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    • "Embryonic stem cells, established from the ICM of blastocyst, can differentiate into all kinds of embryonic tissues, mimicking the pluripotent nature of the origin. Over the last decade, numerous studies have demonstrated steered differentiation of embryonic stem (ES) cells into various tissues by mimicking the signaling environments of the early embryo (Wichterle et al. 2002; Mizuseki et al. 2003; Gotz & Barde 2005; Murry & Keller 2008; Yeo et al. 2008; Zhang et al. 2008). A straightforward application of these techniques is to use these differentiated cells for regenerative medicine and drug discovery. "
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    ABSTRACT: Embryonic stem (ES) cells have been successfully used over the past decade to generate specific types of neuronal cells. In addition to its value for regenerative medicine, ES cell culture also provides versatile experimental systems for analyzing early neural development. These systems are complimentary to conventional animal models, particularly because they allow unique constructive (synthetic) approaches, for example, step-wise addition of components. Here we review the ability of ES cells to generate not only specific neuronal populations but also functional neural tissues by recapitulating microenvironments in early mammalian development. In particular, we focus on cerebellar neurogenesis from mouse ES cells, and explain the basic ideas for positional information and self-formation of polarized neuroepithelium. Basic research on developmental signals has fundamentally contributed to substantial progress in stem cell technology. We also discuss how in vitro model systems using ES cells can shed new light on the mechanistic understanding of organogenesis, taking an example of recent progress in self-organizing histogenesis.
    Full-text · Article · Mar 2012 · Development Growth and Regeneration
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