MicroRNAs miR-25, let-7 and miR-124 regulate the neurogenic potential of Müller glia in mice [NanoString]

In order to identify the miRNAs in postnatal day 2 (P2) retinal progenitor cells (RPCs), and P8, P11, and adult Müller glia (MG) of the neural retina, we isolated the retinal progenitors from Sox2-CreER: Stopf/f-tdTomato and MG from Rlbp-CreER: Stopf/f-tdTomato mice by means of fluorescent activated cell sorting and analyzed their miRNAs using NanoStrings Technologies®. We next compared miRNA expression of RPCs with MG. We found that most specific miRNAs decline with glial maturation (RPC miRNAs) while others increase (MG miRNAs). Overexpression of miRNA-25 found in RPCs and inhibition of MG miRNA let-7 can induce a neurogenic potential in MG and initiates a de novo differentiation toward neuronal fates. We used fluorescence activated cell sorting (FACS) to purify adult RPCs (pooled from 8 retina) and MG (P8, P11 and adult, pooled from 52, 32 and 40 retinas respectively), using an RPC and MG specific cre-lox labeling strategy by crossing Sox2-CreER or Rlbp-CreER mice with stopf/f-tdTomato mice. The RNA was extracted from purified MG. The miRNA expression of P2 RPCs and P8, P11 and adult MG were analyzed using NanoStrings® and nCounter Technologies ®.