Development of Retinal Astroglia

Müller cells and retinal nerve fiber layer astrocytes are the major astroglia of the mammalian retina. They have numerous important functions in adulthood for maintaining neuronal homeostasis as well as in developing retina, where they facilitate key events in the assembly of the retinal tissue. Recent years have seen substantial progress in understanding how these astroglial cells develop and how their development shapes the cells around them. We review the mechanisms underlying the formation, maturation, and spatial patterning of Müller glia and retinal astrocytes, with an emphasis on how they acquire their functional properties. We focus on developmental events that have a major impact on overall retinal integrity, such as the formation of neuro–glial junctions at the outer limiting membrane and the patterning of retinal astrocytes into a template that guides angiogenesis. Finally, we discuss examples of retinal diseases that originate in developmental defects affecting Müller cells or retinal astrocytes. These include certain classes of inherited retinal degenerations, as well as retinopathy of prematurity.