miR-124 promotes proliferation and differentiation of neuronal stem cells through inactivating Notch pathway

Abstract

BackgroundNeural stem cells (NSCs) are able to differentiate into neurons and astroglia. miRNAs have been demonstrated to be involved in NSC self-renewal, proliferation and differentiation. However, the exact role of miR-124 in the development of NSCs and its underlying mechanism remain to be explored.MethodsPrimary NSCs were isolated from embryos of Wistar rats. Immunocytochemistry was used to stain purified NSCs. miR-124, Delta-like 4 (DLL4), ki-67, Nestin, β-tubulin III, glial fibrillary acidic protein (GFAP), HES1, HEY2, and cyclin D1 (CCND1) expressions were detected by qRT-PCR and western blot. The interaction between miR-124 and DLL4 was confirmed by luciferase reporter assay. Cell proliferation was assessed by MTT assay.ResultsNSCs could self-proliferate and differentiate into neurons and astrocyte. miR-124 was up-regulated and DLL4 was down-regulated during NSC differentiation. DLL4 was identified as a target of miR-124 in NSCs. Ectopic expression of miR-124 or knockdown of DLL4 promoted the proliferation and the formation of NSCs to neurospheres. Moreover, miR-124 overexpression or DLL4 down-regulation improved β-tubulin III expression but decreased GFAP expression in NSCs. Furthermore, enforced expression of DLL4 partially reversed the effects of miR-124 on NSCs proliferation and differentiation. Elevated expression of miR-124 suppressed the expressions of HES1, HEY2, and CCND1 in NSCs, while these effects were attenuated following the enhancement of DLL4 expression.ConclusionmiR-124 promoted proliferation and differentiation of NSCs through inactivating Notch pathway.

MicroRNA‐124: An emerging therapeutic target in cancer

“…More data demonstrated that miR‐124 promoted neuronal differentiation of and neurite outgrowth in mouse inner ear neural stem cells (NSCs) by regulating tropomyosin receptor kinase B (TrkB) and cell division control protein 42 homolog (Cdc42) . Another study also elucidated that miR‐124 promoted neural differentiation of NSCs by directly targeting DLL4 through suppression of the Notch pathway . Some scholars have suggested that Lhx2 is a primary target gene of miR‐124a and that Lhx2 downregulation by miR‐124a is required for the prevention of apoptosis in the developing retina and for proper axonal development of hippocampal neurons .…”

“…34 Another study also elucidated that miR-124 promoted neural differentiation of NSCs by directly targeting DLL4 through suppression of the Notch pathway. 38 Some scholars have suggested that Lhx2 is a primary target gene of miR-124a and that Lhx2 downregulation by miR-124a is required for the prevention of apoptosis in the developing retina and for proper axonal development of hippocampal neurons. 39 Kaili Liu et al showed that NeuroD1 could act as a direct target of miR-124 in vivo to control Xenopus cell proliferation and neurogenesis.…”

MicroRNA‐212 promotes the recovery function and vascular regeneration of endothelial progenitor cells in mice with ischemic stroke through inactivation of the notch signaling pathway via downregulating MMP9 expression

“…MMP9 functions as a transcription factor, which can bind to and inhibit the Notch1 signaling pathway (Bin Hafeez et al, ). The Notch signaling pathway is an evolutionarily highly conserved signaling pathway which plays an important role in serval biological processes, such as cell proliferation, differentiation and apoptosis (Jiao, Liu, Yao, & Teng, ). In mammals, there are four Notch receptors (Notch1, 2, 3, 4), and upon binding by a membrane bound ligand on a neighboring cell, the Notch receptors undergo proteolytic cleavages leading to the release of the Notch intracellular domain (Zou, Luo, & Xiang, ).…”

Selective effects of miRNA effector protein Argonaute on miRNA processing

“…Distruption of miR-124 results in neural abnormalities, indicating that miR-124 is important for the maturation and survival of dentate gyrus neurons and retinal cones (Sanuki, Onishi et al 2011). Overexpression of miR-124 promotes neuronal differentiation in a variety of neural progenitor cells, including mesenchymal, brain tumor and neuronal stem cells (Silber, Lim et al 2008, Zou, Chen et al 2014, Mondanizadeh, Arefian et al 2015, Jiang, Du et al 2016, Jiao, Liu et al 2017, Sharif, Ghahremani et al 2017, and overexpression of both miR-124 and miR-9 were sufficient to induce differentiation of neural progenitor cells and fibroblasts into neurons (Krichevsky, Sonntag et al 2006, Yoo, Sun et al 2011. miR-124 has been shown to be an important neuronal fate determinant for the neuronal stem cells in the subventricular zone (SVZ), the largest neurogenic region in the adult mammalian brain (Cheng, Pastrana et al 2009, Akerblom, Sachdeva et al 2012.…”

“…Moreover, SCP1 (Small C-terminal domain phosphatase 1) which is recruited by REST to RE-1 element to function as a silencer for neuronal genes in non-neuronal cells (Yeo, Lee et al 2005), is directly targeted by miR-124 on its 3' UTR during neuronal differentiation (Visvanathan, Lee et al 2007). Additionally, miR-124 also regulates neuronal differentiation through the Notch signaling pathway via repression of the Notch ligands Jag1 (Jagged1) (Cheng, Pastrana et al 2009, Liu, Chopp et al 2011) and DLL4 (Delta-like 4) (Jiao, Liu et al 2017), allowing exit from stem cell self-renewal and differentiation into neuronal cell fate.…”