Müller glial cells as novel photosensitive components in the vertebrate inner retina

MARCHESE, NATALIA A.; RIOS, MAXIMILIANO N.; GUIDO, MARIO E.

Congreso; XXXVI Reunión Anual de la Sociedad Argentina de Investigación en Neurociencias; 2021

Sociedad Argentina de Investigación en Neurociencias

Located all along the inner retina, Müller glial cells(MC) take part in development, metabolism, neurotransmission, injury response and regeneration. Non-canonical opsins in the retina sense environmental lighting conditions along the day to drive specific non-image forming functions(NIF), that include the entrainment of circadian rhythms.Our recent studies in the understanding of NIF in the avian inner retina are focused on light-driven responses of MC. Initially, we identified a gradual increase, throughout development up to the time of hatching, in the expression of Opn3 and glial markers. Furthermore, MC in culture show photic-regulated expression and location of Opn3. Moreover, we identified a direct photic response of MC to a blue light(BL) pulse as an increase in intracellular Ca2+ levels. This response is sustained for several minutes, dependent on opsin activation, specific to BL stimulation and comprises three subpopulations: A. ≥20% increase; B. 10-20% increase; and C. No-increase. MC activation involves Ca2+ release from endoplasmic reticulum(ER); as their depletion decreased the percentage of MC effectively responding to BL, whereas an extracellular Ca2+ chelator did not. Indeed, cytosolic Ca2+ increase goes along with a decrease in Ca2+ levels in the ER.MC can be postulated as new intrinsically photosensitive components in the inner retina of vertebrates potentially contributing to local circuits in the regulation of various physiological processes by BL