Specific MicroRNAs Modulate Embryonic Stem Cell–Derived Neurogenesis

Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Stem Cells (Impact Factor: 7.13). 05/2006; 24(4):857-64. DOI: 10.1634/stemcells.2005-0441
Source: PubMed

ABSTRACT MicroRNAs (miRNAs) are recently discovered small non-coding transcripts with a broad spectrum of functions described mostly in invertebrates. As post-transcriptional regulators of gene expression, miRNAs trigger target mRNA degradation or translational repression. Although hundreds of miRNAs have been cloned from a variety of mammalian tissues and cells and multiple mRNA targets have been predicted, little is known about their functions. So far, a role of miRNA has only been described in hematopoietic, adipocytic, and muscle differentiation; regulation of insulin secretion; and potentially regulation of cancer growth. Here, we describe miRNA expression profiling in mouse embryonic stem (ES) cell- derived neurogenesis in vitro and show that a number of miRNAs are simultaneously co-induced during differentiation of neural progenitor cells to neurons and astrocytes. There was a clear correlation between miRNA expression profiles in ES cell-derived neurogenesis in vitro and in embryonal neurogenesis in vivo. Using both gain-of-function and loss-of-function approaches, we demonstrate that brain-specific miR-124a and miR-9 molecules affect neural lineage differentiation in the ES cell-derived cultures. In addition, we provide evidence that signal transducer and activator of transcription (STAT) 3, a member of the STAT family pathway, is involved in the function of these miRNAs. We conclude that distinct miRNAs play a functional role in the determination of neural fates in ES cell differentiation.

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Available from: Kenneth S Kosik, Sep 01, 2015
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    • "It seems a primary function of miR-124 is to maintain neuronal state by downregulating non-neuronal mRNAs. Ectopic expression of miR- 124 in HeLa cells, neuroblastoma cell lines, and embryonic stem cells represses the expression of non-neuronal transcripts and shifts the gene expression profile towards neuronal state [Lim, 2005; Krichevsky, 2006; Makeyev, 2007]. It has been reported that neurite outgrowth is promoted by overexpressing miR-124 in mouse P19 cells, whereas its downregulation delays neurite outgrowth and reduces the amount of acetylated a-tubulin [Yu, 2008]. "
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    ABSTRACT: MicroRNAs play an important role in neuronal development and function. miR-124 is the most abundantly expressed miRNA in the nervous system. Several different mRNA targets have been proposed for miR-124, but the precise function of endogenous miR-124 and its mRNA targets remain to be further elucidated. Specificity protein 1 (Sp1) is a transcription factor that plays key roles in many cell processes including cell cycle. However, this transcription factor is nearly absent in differentiated neurons and a remarkable suppression of Sp1 expression was shown after neurogenesis. Since miR-124 is expressed abundantly in neurons and because Sp1 levels decrease during neurogenesis, it is possible that miR-124 could regulate the expression of Sp1 during neuronal development. Therefore, the aim of the present study was to evaluate the putative targeting of Sp1 by miR-124. Overexpression of miR-124 using a plasmid coding for pri-miR-124 in HEK293 cells decreased the expression of Sp1 mRNA. The results of dual-luciferase reporter assay demonstrated that miR-124 directly targeted the 3‘-untranslated regions of Sp1 mRNA. To evaluate whether Sp1 expression was regulated by miR-124 during the process of neuronal differentiation, Adipose-derived mesenchymal stem cells (A-MSCs) were differentiated into neuron-like cells. The results of qPCR analysis showed that with the gradual increase of miR-124 expression during neurogenesis, the expression of Sp1 mRNA decreased accordingly. In summary, this study demonstrated for the first time that miR-124 is able to suppress Sp1 expression, which in turn affected the neuronal differentiation of mesenchymal stem cells. This article is protected by copyright. All rights reserved
    Journal of Cellular Biochemistry 01/2015; 116(6). DOI:10.1002/jcb.25045 · 3.37 Impact Factor
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    • "In this study, we used miR-124 to regulate neural conversion genes. MiR-124 is expressed exclusively in neurons, is known to promote neurogenesis in vitro and in vivo, and also has a potential role in regulating activities of postmitotic neurons (A ˚ kerblom et al., 2012; Cheng et al., 2009; Krichevsky et al., 2006). To achieve self-regulation of our conversion vectors, we inserted four complementary binding sites of miR-124 (Figure 1A). "
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    ABSTRACT: Recent findings show that human fibroblasts can be directly programmed into functional neurons without passing via a proliferative stem cell intermediate. These findings open up the possibility of generating subtype-specific neurons of human origin for therapeutic use from fetal cell, from patients themselves, or from matched donors. In this study, we present an improved system for direct neural conversion of human fibroblasts. The neural reprogramming genes are regulated by the neuron-specific microRNA, miR-124, such that each cell turns off expression of the reprogramming genes once the cell has reached a stable neuronal fate. The regulated system can be combined with integrase-deficient vectors, providing a nonintegrative and self-regulated conversion system that rids problems associated with the integration of viral transgenes into the host genome. These modifications make the system suitable for clinical use and therefore represent a major step forward in the development of induced neurons for cell therapy. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.
    Cell Reports 12/2014; 9(5). DOI:10.1016/j.celrep.2014.11.017 · 8.36 Impact Factor
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    • "Recent studies have suggested that small, non-coding RNA species known as microRNA (miRNA) play a role in supporting temporo-spatial traffic of neuronal mRNA (Goldie and Cairns, 2012). Many miRNA demonstrate brain-specific (Smirnova et al., 2005; Krichevsky et al., 2006) and region-specific (Hollins et al., 2014) expression and have been shown to regulate key aspects of brain development and neuronal morphology (Giraldez et al., 2005), including patterning and arealisation, dendritic branching (Xu et al., 2008) and spine volume (Schratt et al., 2006). The presence of miRNA in exosomes suggests they may also play a role in activity-driven communication (Fauré et al., 2006). "
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    ABSTRACT: The SH-SY5Y culture system is a convenient neuronal model with the potential to elaborate human/primate-specific transcription networks and pathways related to human cognitive disorders. While this system allows for the exploration of specialized features in the human genome, there is still significant debate about how this model should be implemented, and its appropriateness for answering complex functional questions related to human neural architecture. In view of these questions we sought to characterize the posttranscriptional regulatory structure of the two-stage ATRA differentiation, BDNF maturation protocol proposed by Encinas et al. (2000) using integrative whole-genome gene and microRNA (miRNA) expression analysis. We report that ATRA-BDNF induced significant increases in expression of key synaptic genes, brain-specific miRNA and miRNA biogenesis machinery, and in AChE activity, compared with ATRA alone. Functional annotation clustering associated BDNF more significantly with neuronal terms, and with synaptic terms not found in ATRA-only clusters. While our results support use of SH-SY5Y as a neuronal model, we advocate considered selection of the differentiation agent/s relative to the system being modeled.
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