Biology subjects

Contin, M. A.

Publications and source records attributed to Contin, M. A..

2 recordsLinked to original sources

bioRxiv2024

Stress granule induction in rat retinas damaged by constant LED light.

ObjectivesStress granules (SGs) are cytoplasmic biocondensates formed in response to various cellular stressors, contributing to cell survival. While implicated in diverse pathologies, their role in retinal degeneration (RD) remain unclear. We aimed to investigate SG formation in the retina and its induction by excessive LED light in a RD model. MethodsRat retinas were immunohistochemically analyzed for SG markers G3BP1 and eIF3, and SGs were also visualized by RNA FISH. Additionally, SGs were induced in primary retinal cell and eyeball cultures using sodium arsenite. Light exposure experiments utilized LED lamps with a color temperature of 5,500 K and 200 lux intensity for short-term or 2-8-day exposures. ResultsSGs were predominantly detected in retinal ganglion cells (RGCs) and inner nuclear layer (INL) cells, confirmed by sodium arsenite induction. SG abundance was higher in animals exposed to light for 2-8 days compared to light/dark cycle controls. RGCs consistently exhibited more SGs than INL cells, and INL cells more than outer nuclear layer cells (Scheirer-Ray-Hare test: H 13.2, p = 0.0103 for light condition, and H 278.2, p < 0.00001 for retinal layer). These observations were consistent across four independent experiments, each with three animals per light condition. ConclusionsThis study identifies SGs in the mammalian retina for the first time, with increased prevalence following excessive LED light exposure. RGCs and INL cells showed heightened SG formation, suggesting a potential protective mechanism against photodamage. Further investigations are warranted to elucidate SGs role in shielding against light stress and their implications in retinopathies.

cell biology↗

bioRxiv2021

Glial Cell Responses to constant low Light exposure in Rat Retina.

Retinal damage promoted by constant illumination of low intensity resulted in a diminution in classical photoreceptors cells. Glial cells exert profound effects on neurons, vasculature and other glial cells. Macroglia and microglia with specific morphological, physiological, and antigenic characteristics may play an essential role in both the maintenance and control of retinal homeostasis, or to exert mechanisms that promote cell death. The role of glial cells and immune function in the pathogenesis promoted by low light is poorly understood. We performed glial cells characterization along the time-course of retinal degeneration induced by chronic exposure to low intensity of light in Wistar rats. We exposed the animals at constant light from 2 to 8 days and assessed the retinal glia. After 6 days of light exposure, retinas presented increased levels of GFAP, a macroglia marker and microglia markers Iba1 and CD68 displayed increased mRNA levels after 6 days. The number of Iba1 positive cells increased in the outer nuclear layer, showing ameboid morphology with thicker processes characteristic of microglial activated cells. The expression levels of immune mediators TNF-{square} and IL-6 were also significantly increased after 6 days. Finally, chemokines analysis showed that CX3CR1 and CCL2 expression levels were significantly elevated after 6 days. Hence, all the events of glial activation occurred after 5-6 days of constant light exposure, when the number of cells of the outer nuclear layer has already decreased significantly. Herein we demonstrated that glial and immune activation are secondary to neurodegeneration; in this scenario, our results suggest that photoreceptor death is an early event that may be induced by phototransduction-dependent mechanisms.

neuroscience↗