MicroRNA-125b Promotes Neuronal Differentiation in Human Cells by Repressing Multiple Targets

Whitehead Institute for Biomedical Research, 9 Cambridge Center, Suite 601, Cambridge, MA 02142, USA.
Molecular and Cellular Biology (Impact Factor: 4.78). 08/2009; 29(19):5290-305. DOI: 10.1128/MCB.01694-08
Source: PubMed


MicroRNAs (miRNAs) are a class of small noncoding RNAs that regulate gene expression at the posttranscriptional level. Research on miRNAs has highlighted their importance in neural development, but the specific functions of neurally enriched miRNAs remain poorly understood. We report here the expression profile of miRNAs during neuronal differentiation in the human neuroblastoma cell line SH-SY5Y. Six miRNAs were significantly upregulated during differentiation induced by all-trans-retinoic acid and brain-derived neurotrophic factor. We demonstrated that the ectopic expression of either miR-124a or miR-125b increases the percentage of differentiated SH-SY5Y cells with neurite outgrowth. Subsequently, we focused our functional analysis on miR-125b and demonstrated the important role of this miRNA in both the spontaneous and induced differentiations of SH-SH5Y cells. miR-125b is also upregulated during the differentiation of human neural progenitor ReNcell VM cells, and miR-125b ectopic expression significantly promotes the neurite outgrowth of these cells. To identify the targets of miR-125b regulation, we profiled the global changes in gene expression following miR-125b ectopic expression in SH-SY5Y cells. miR-125b represses 164 genes that contain the seed match sequence of the miRNA and/or that are predicted to be direct targets of miR-125b by conventional methods. Pathway analysis suggests that a subset of miR-125b-repressed targets antagonizes neuronal genes in several neurogenic pathways, thereby mediating the positive effect of miR-125b on neuronal differentiation. We have further validated the binding of miR-125b to the miRNA response elements of 10 selected mRNA targets. Together, we report here for the first time the important role of miR-125b in human neuronal differentiation.

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Available from: Beiyan Zhou
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    • "We asked whether LSD1+8a expression was also dynamically regulated during human neuronal differentiation using SH-SY5Y cells, which are human neuronal cells derived from neuroblastoma. Sequential exposure of these cells to retinoic acid (RA) for 4 days (day D0 to D4) and then to brainderived neurotrophic factor (BDNF) in a serum-free medium for 5 days (day D4/B0 to B5) yields a homogeneous population of differentiated neuronal cells that possess many features of primary neurons (Figure S1A) (Encinas et al., 2000; Le et al., 2009). While exposure of SH-SY5Y cells to RA slightly reduced the level of both types of LSD1 transcripts (LSD1-8a and LSD1+8a), BDNF treatment increased the expression level of LSD1+8a isoforms more than that of LSD1-8a isoforms between day B0 and B5 (3.85 ± 0.3 versus 1.47 ± 0.15) (Figure 1A). "
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    • "These experiments showed that overexpression of LSD1 inhibited neurite extension and the expression of neuronal markers in differentiating SH- SY5Y cells, effects that could be abolished by co-overexpression of Jade-2 but not Jade-2-C202A or Jade-2-C243A (Figures 7C and 7D). Full differentiation of SH-SY5Y cells by sequential exposure to RA and brain-derived neurotrophic factor (BDNF0) (Encinas et al., 2000; Le et al., 2009) (Figure S5B) showed that both mRNA and protein levels of LSD1 decreased, whereas the expression of Jade-2 did not change during neuronal differentiation (Figure S5C). Subsequently, we showed that LSD1 inhibits neuronal differentiation of SH-SY5Y cells, whereas Jade-2 promotes this process, which could be offset by simultaneous overexpression of LSD1 (Figures S5D and S5E). "
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