MiR-125b orchestrates cell proliferation, differentiation and migration in neural stem/progenitor cells by targeting Nestin.

<div class="collapsible-content"><h4>Background</h4><p style="line-height: 160%">The emerging concept is that microRNAs (miRNAs) play a central role in controlling stem cell self-renewal and fate determination by regulating the expression of stem cell regulators. <em>miR-125b</em>, one of neuronal miRNAs, recently was found to be necessary for neural differentiation of neural stem/progenitor cells (NS/PCs). However, the other specific biological role of <em>miR-125b</em> in NS/PCs is little known. We used rat NS/PCs as a model system to study the role of <em>miR-125b</em> in governing the behavior of NS/PCs. </p><h4>Results</h4><p style="line-height: 160%">We report here the transfection of exogenous <em>miR-125b</em> inhibited proliferation of NS/PCs but promoted differentiation and migration. Whereas anti-miR-125b had the opposite effect. Similar results were observed when <em>Nestin</em> was knocked down by siRNA. Subsequently, we demonstrated that <em>Nestin</em> was a direct functional target of <em>miR-125b</em>. <em>MiR-125b</em> downregulates the expression of luciferase through <em>Nestin</em> 3&rsquo;untranslated region (3&rsquo;-UTR), and the regulation was abolished by mutations in the <em>miR-125b</em> binding site. <em>MiR-125b</em> targeted the 3'-UTR of <em>Nestin</em> and reduced the abundance of <em>Nestin</em> at both mRNA and protein levels. </p><h4>Conclusion</h4><p style="line-height: 160%">The results provided new insight into the function by which <em>miR-125b</em> modulates NS/PCs proliferation, differentiation and migration. The data also indicated the regulatory role of <em>miR-125b</em> in NS/PCs might through the suppression of <em>Nestin</em> expression. </p>