MicroRNAs role in retinal stem cells regulation

Abstract

The retina is an essential structure for sensory perception in vertebrates contains photoreceptors (rods and cones) and various subtypes of neurons (bipolar cells, ganglion, amacrine and horizontal) connected in a complex neural network for processing visual information. This tissue is susceptible to various environmental and genetic degenerative insults resulting in visual loss or complete blindness and, although not able to regenerate, some epithelial cells located in the peripheral retina, in the Ciliary Epithelium region, were identified as progenitor/stem cells with the capacity to generate retinal neurons. Although Ciliary Epithelium cells has presented retinal regenerative capacity, this ability is not developed properly, that indicates the presence of inhibitory mechanisms acting on the regenerative potential of these cells. Thus, this project aims to detect and experimentally manipulate a group of small RNAs known to promote the inhibition of the regenerative capacity of mammalian cells: microRNAs. We believe that this manipulation can promote the mechanisms induction for pluripotency and progenitor genes activation from retinal progenitor/stem cells located in the Ciliary Epithelium. The first step will consist in identifying the expression of mature microRNAs in Ciliary Epithelium cells, as well as the relevant targets of these microRNAs. The second step consist in Experimental Manipulation (overexpression and inhibition) of the selected microRNAs in Ciliary Epithelium cell culture experiments and evaluation of progenitor and pluripotent capacity acquired. In the third step, we will study the presence of microvesicles structures in Ciliary Epithelium cells (structures responsible for microRNAs storage) as well as its release, content analysis, incorporation into adjacent cells and its effect on the regenerative capacity. Finally, animals with retinal degeneration will be evaluated for the presence and expression of mature microRNAs in Ciliary Epithelium cells, presence of cellular microvesicles, content analysis of these microvesicles and its effect on the expression of pluripotent and retinal progenitor genes. This study will contribute to a better understanding of the factors involved in retinal regeneration and visual rescue, aiming a possible retinal regenerative therapy or complement to currently available therapies. (AU)