Expression of miR-145 and Its Target Proteins Are Regulated by miR-29b in Differentiated Neurons
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MicroRNAs (miRNAs) are emerging as the most potential regulator of neuronal development. Recent studies from our lab and elsewhere have demonstrated a direct role of miRNAs in regulating neuronal differentiation and synaptogenesis. MicroRNA-145, a miRNA identified to regulate pluripotency of stem cells, downregulates the protein levels of reprogramming transcription factors (RTFs) like OCT4, SOX2, and KLF4 (cell, 137,647–658,2009). Studies have shown that miR-145 is multifunctional and crucial for fate determination of neurons. In our recently published study, we have identified a set of miRNAs including miR-145 and miR-29b families differentially expressed in SH-SY5Y cells exposed sequentially with retinoic acid + brain-derived neurotrophic factor (RA+BDNF) for differentiation into mature neurons (Mol Neurobiol (2016) doi: https://doi.org/10.1007/s12035-016-0042-9). In the present study, we have identified the role of miR-29b in upregulation of miR-145, which is upregulated after exposure of RA+BDNF in a P53-dependent manner. In differentiating SH-SY5Y cells, expression of miR-29b downregulates expression of P85α, a P53 inhibitor, which results in upregulation of miR-145 and downregulation of RTF proteins. Ectopic expression of miR-145 and miR-29b in amounts equivalent to their endogenous expression has induced G1 phase cell cycle arrest. In conclusion, our studies have identified miR-29b as an upstream regulator of miR-145 and targets its RTF genes during differentiation of SH-SY5Y cells.
KeywordsMicroRNAs Neuronal differentiation Reprogramming transcription factors (RTFs) P53,SH-SY5Y cells SOX2 KLF4 OCT4 NANOG miR-145 miR-29b
brain-derived neurotrophic factor
integrated density value
polymerase chain reaction
reprogramming transcription factor
phosphate buffer saline
Mr. Abhishek Jauhari is grateful to UGC, New Delhi, and Ms. Tanisha Singh is grateful to DST, New Delhi, for providing research fellowships. The technical assistance of Mr. B S Pandey and Mr. Puneet Khare is also gratefully acknowledged. The CSIR-IITR communication reference number is 3493.
Funding for the work carried out in the present study had been provided by the CSIR network project (miND).
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
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