A7 Nicotinic Expression And Function In Human Retinal Pigment Epithelium Cells

MADER J; FERNANDEZ DELIAS, M.F.; CHRESTIA, J.F.; SOTELO FA; ESANDI, M.C.; BOUZAT, C.

Mar del Plata

Congreso; REUNIÓN CONJUNTA SAIC SAB AAFE AACYTAl 2023; 2023

The α7 nicotinic receptor (nAChR) is one of the most abundant nAChRsin the nervous system and is also present in non-neuronalcells, including immune and epithelial cells. It is involved in cognition,memory, pain, neuroprotection and inflammation and its potentiationhas emerged as a therapeutic strategy for neurological, neurodegenerative,and inflammatory disorders. Given that the increasein oxidative stress in retinal pigment epithelial cells contributes to thedevelopment of age-related macular degeneration and that α7 activationexerts cell protective effects, we explored the presence andfunctional relevance of α7 in D407 retinal pigment epithelium cells.By confocal microscopy using the α7 specific antagonist α-bungarotoxinlabeled with Alexa 488 and real time-PCR we demonstratedthe presence of α7 in these epithelial cells. To simulate the eventsoccurring in age-related macular degeneration, we treated cells with500 μM ferric ammonium citrate (FAC) for 48 h to induce stressdamage and measured reactive oxygen species (ROS) with the fluorescentprobe DCFH-DA and cell viability by the MTT assay. FACtreatment resulted in a significant 56 ± 23% increase in ROS levelswith respect to the control. To determine if α7 protects against oxidativedamage, we exposed cells for 4 h to a specific α7 agonist,PNU-282987, before the FAC treatment. This exposure reduced 29± 3% basal levels of ROS. Notably, PNU-282987 exhibited protectiveeffects against the FAC treatment, leading to a reduction of 46 ±15% in ROS levels when compared to the treated cells. In line withthese observations, exposure to the α7 agonist restored the 20%reduction in cell viability induced by FAC. Overall, we demonstratedfor the first time the presence of α7 in the D407 cell line, which is amodel system for studying various retinal diseases, and its protectiverole against oxidative damage, a key factor linked to the onsetof macular degeneration.