Abstract
Purpose: :
Adaptation to different levels of illumination is central to the function of the retina. We were interested to study whether the process of light-dark adaptation in the mouse retina involves microRNAs and if so, which cellular targets are influenced by microRNAs.
Methods: :
We used sequencing techniques to profile expression patterns of microRNAs quantitatively and qualitatively that derived from either light- or dark-adapted adult retinas. Kinetics of microRNA turnover was studied by QPCR and its mechanism was revealed by pharmacology. We used target prediction algorithms to identify potential microRNA targets that were verified by gene arrays and biochemical techniques. In vivo microRNA knockdown studies were also performed by cell-type specific expression of so called "microRNA sponges".
Results: :
We demonstrated that levels of the miR-183/96/182 cluster, miR-204, and miR-211 were regulated by different light levels in the mouse retina. Concentrations of these micro-RNAs were down-regulated during dark adaptation and up-regulated in light-adapted retinas, with rapid decay and increased transcription being responsible for the respective changes. We identified the voltage-dependent glutamate transporter Slc1a1 as one of the miR-183/96/182 targets in photoreceptor cells. We found that microRNAs in retinal neurons decay much faster than microRNAs in non-neuronal cells.
Conclusions: :
Our results demonstrate that microRNA metabolism in retinal neurons is higher than in most other cells types and linked to neuronal activity.
Keywords: genetics • ion transporters • transcription