Studies about the cooperative signaling between p75 NTR and Trk receptors in the modulation of choroidal neovascularization.

SUBIRADA, P. V.; TOVO, A.; VAGLIENTI, M.V.; VICENTIN, D.; RIBOTTA, N.A.; LUNA, J.D.; SARAGOVI, H.U.; SANCHEZ, M.C.; ANASTASIA, A.; BARCELONA, P.F.

Denver

Congreso; 2022 ARVO ANNUAL MEETING; 2022

ARVO FOUNDATION

Purpose: Neovascular age-related macular degeneration (AMD) commonly causes vision lossfrom aberrant angiogenesis, termed choroidal neovascularization (CNV). To unravel themechanisms underlying CNV, we focused on the p75 neurotrophin receptor (p75 NTR ), atransmembrane protein known to mediate neuronal survival and death, and also vascularplasticity. P75 NTR can couple to different co-receptors to transduce intracellular signals. Ourprevious results showed that p75 NTR increases 7 days post-laser in retinal glia (GS+ or GFAP+)and RPE (retinal pigment epithelium)-choroid infiltrate (F4/80+) of mice with CNV. Thedeletion of the receptor reduced CNV area and prevented photoreceptor dysfunction. It has beenreported that p75 NTR can potentiate Trk signalling in some scenarios. Thus, we aim to determineif p75 NTR modulates Trk activation to modify neovessel formation in a mouse model of laser-induced CNV. Methods: 2- months old mice were anesthetized and their pupils were dilated;then, 4 injuries were performed in the retina using a photocoagulation laser with a 532nmwavelength slit lamp. 7 days after laser the mice were sacrificed. Samples include RPE-Choroidflatmounts, retina cryosections, and retinal and RPE-Choroid extracts processed separately forWestern blot. WT (n=15) and p75 NTR KO (n=21) mice were included in the experimental designand animals without CNV (n=10) were used as control. Results: We estimated Trk activationthrough the activation of its downstream signaling molecule ERK. We detected decreasedexpression of phosphor-ERK in retina from CNV mice respect to control (p=0,014) and similarphospho-ERK levels in RPE-choroid 7 days post laser (p=0,227) by Western Blot.Immunostaining did not show localization of pan-Trk nor phospho-ERK in retinal glia.Similarly, no overlapping was detected between pan-Trk and RPE-Choroid infiltrate assessed inRPE-Choroid flatmounts. Consistently, p75 NTR KO mice showed equal p-ERK levels 7 days afterlaser in retina (p=0,322) and RPE-Choroid (p=0,353). Conclusions: In sum, our results suggestthat the formation of vascular tufts that are produced during the CNV is not mediated by thecooperative signalling between p75 NTR and Trk receptors.