Transactivation of P53 by cypermethrin induced miR-200 and apoptosis in neuronal cells

Abstract

Cypermethrin, a pyrethroid pesticide, has been shown to induce neurotoxicity in adult mammals. However, studies are also needed to explore its toxicity in developing brains and understand its mechanism of action in neurons. In our recently published study, using nerve growth factor (NGF) differentiated PC12 cells, we have identified the miR-200 family as major up-regulated miRNAs, which regulate differentiation of PC12 cells into neurons. In the present study, the toxicity of cypermethrin is compared between undifferentiated and neuron-like differentiated PC12 cells, and role of the miR-200 family is studied in cypermethrin-induced neuronal cell death. Our studies have shown that a non-cytotoxic concentration of cypermethrin selectively induces the miR-200 family and apoptosis in differentiated PC12 cells, while no significant alterations were observed in undifferentiated PC12 cells. Further, our studies have demonstrated that cypermethrin induces miR-200 by increasing P53 levels in differentiated PC12 cells and we have identified a direct correlation between the expression of miR-200 and levels of P53 in PC12 cells. Further, BCL2 is identified as a target protein of miR-200b/c, and down-regulation of the BCL2 protein regulates cypermethrin-induced apoptosis of differentiated PC12 cells. Rescue experiments carried out with inhibitors of the miR-200 family, have further confirmed the role of the miR-200 family in apoptosis of differentiated PC12 cells exposed to cypermethrin. In conclusion, our studies have shown that differentiated PC12 cells are more sensitive to cypermethrin exposure than naïve and undifferentiated PC12 cells, and P53 mediated induction of the miR-200 family regulates cypermethrin-induced apoptosis of differentiated neuron-like PC12 cells.