Glial Bmal1 role in mammalian retina daily changes

Visual information processing in the retina requires the rhythmic expression of clock genes. The intrinsic retinal circadian clock is independent of the master clock located in the hypothalamic suprachiasmatic nucleus and emerges from retinal cells, including glia. Less clear is how glial oscillators influence the daily regulation of visual information processing in the mouse retina. Here, we demonstrate that the adult conditional deletion of the gene Bmal1 in GLAST-positive glial cells alters retinal physiology. Specifically, such deletion was sufficient to lower the amplitude of the electroretinogram b-wave recorded under light-adapted conditions. Furthermore, recordings from > 20,000 retinal ganglion cells (RGCs), the retina output, showed a non-uniform effect on RGCs activity in response to light across different cell types and over a 24-h period. Overall, our results suggest a new role of a glial circadian gene in adjusting mammalian retinal output throughout the night-day cycle.