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: 6.52). 05/2006; 24(4):857-64. DOI: 10.1634/stemcells.2005-0441
Source: PubMed


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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    • "While Ngn1 could both activate the neurogenic program and simultaneously inhibit the astrogliogenic program (Figure 3—figure supplement 1C), miR-9 appeared to be only involved in the inhibition of glial fate. We confirmed that transfection of mouse NPCs with exogenous miR-9 duplex blocked phosphorylation of Stat1/3 without altering their protein levels (Figure 3B), which is in agreement with the work by Krichevsky et al. (2006). To explore how miR-9 inhibits Stat phosphorylation, we scanned the 3′ UTRs of three upstream components of the Jak-Stat pathway (www.targetscan.com) "
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    ABSTRACT: It has been postulated that a proneural factor, neurogenin 1 (Ngn1), simultaneously activates the neurogenic program and inhibits the alternative astrogliogenic program when specifying the neuronal fate. While Ngn1 substantially suppresses the activation of the astrogliogenic Jak-Stat pathway, the underlying molecular mechanism was unknown. Here, by employing in vivo and in vitro approaches, we report that Ngn1 binds to the promoter of a brain-enriched microRNA, miR-9, and activates its expression during neurogenesis. Subsequently, our in vitro study showed that miR-9 directly targets mRNAs of Lifr-beta, Il6st (gp130), and Jak1 to down-regulate these critical upstream components of the Jak-Stat pathway, achieving inhibition of Stat phosphorylation and consequently, suppression of astrogliogenesis. This study revealed Ngn1 modulated non-coding RNA epigenetic regulation during cell fate specifications.
    eLife Sciences 08/2015; 4. DOI:10.7554/eLife.06885 · 9.32 Impact Factor
    • "Two such miRNAs are miR-9 and miR-124a, which are highly expressed in neurons and astrocytes of the brain. Together, these miRNAs indirectly modulate the phosphorylation status of STAT3, an important intracellular signaling molecule mediating the inhibition of neuronal terminal differentiation (Krichevsky et al. 2006; Delaloy et al. 2010). Inhibition of miR-9 increases STAT3 phosphorylation, resulting in reduced neuronal development , whereas overexpression of miR-9 and miR-124a decreases STAT3 phosphorylation, limiting development of the astrocytic lineage. "
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    ABSTRACT: The field of miRNA biology is relatively young, but its impact on our understanding of the regulation of a wide array of cell functions is far-reaching. The importance of miRNAs in development has become nearly ubiquitous, with miRNAs contributing to development of most cells and organs. Although miRNAs are clearly interwoven into known regulatory networks that control cell development, the specific modalities by which they intersect are often quite distinct and cleverly achieved. The frequently emerging theme of feed-back and feed-forward loops to either counterbalance or reinforce the gene programs that they influence is a common thread. Many of these examples of miRNAs as developmental regulators are presently found in organs with different miRNAs and targets, whereas novel, unexpected themes emerge in the context of mouse development as we learn more about this rapidly developing area of biology. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.
    Cold Spring Harbor perspectives in biology 07/2015; 7(7). DOI:10.1101/cshperspect.a008144 · 8.68 Impact Factor
    • "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 · 3.26 Impact Factor
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