microRNA expression in the neural retina: Focus on Muller glia

The neural retina hosts a unique specialized type of macroglial cell that not only preserves retinal homeostasis, function, and integrity but also may serve as a source of new neurons during regenerative processes: the Muller cell. Precise microRNA-driven mechanisms of gene regulation impel and direct the processes of Muller glia lineage acquisition from retinal progenitors during development, the triggering of their response to retinal degeneration and, in some cases, Muller cell reprogramming and regenerative events. In this review we survey the recent reports describing, through functional assays, the regulatory role of microRNAs in Muller cell physiology, differentiation potential, and retinal pathology. We discuss also the evidence based on expression analysis that points out the relevance of a Muller glia-specific microRNA signature that would orchestrate these processes.