Studies about the cooperative signaling between p75NTR and Trk receptors in the modulation of choroidal neovascularization

SUBIRADA, PAULA V.; TOVO, A.; VAGLIENTI, MARIA V.; DANISA VICENTIN; NICOLÁS RIBOTTA; LUNA PINTO, JD; HORACIO URI SARAGOVI; SÁNCHEZ, MARÍA C.; ANASTASIA, A.; BARCELONA, PABLO F.

Denver, Colorado

Congreso; Annual Meeting of The Association for Research in Vision and Ophthalmology ? ARVO 2022; 2022

ARVO

Purpose : Neovascular age-related macular degeneration (AMD) commonly causes vision loss from aberrant angiogenesis, termed choroidal neovascularization (CNV). To unravel the mechanisms underlying CNV, we focused on the p75 neurotrophin receptor (p75NTR), a transmembrane protein known to mediate neuronal survival and death, and also vascular changes. P75NTR can couple to different co-receptors to transduce intracellular signals. Our previous results showed that p75NTR increases 7 days post-laser in retinal glia (GS+ or GFAP+) and RPE (retinal pigment epithelium)-choroid infiltrate (F4/80+) cells of mice with CNV. The deletion of the receptor reduced CNV area and prevented photoreceptor dysfunction. It has been reported that p75NTR can potentiate Trk signalling in some scenarios. Thus, we aim to determine if p75NTR 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 532nm wavelength slit lamp. 7 days after laser the mice were sacrificed. Samples include RPE-Choroid flatmounts, retina cryosections for immunostaining, and retinal and RPE-Choroid extracts processed separately for Western blot. WT (n=15) and p75NTR KO (n=21) mice were included in the experimental design and animals without CNV (n=10) were used as control.Results : We estimated Trk activation through the activation of its downstream signaling molecule ERK. We detected decreased expression of phosphor-ERK in retina from CNV mice respect to control (p=0,014) and similar phospho-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 in RPE-Choroid flatmounts. Consistently, p75NTRKO mice showed equal phospho-ERK levels 7 days after laser in retina (p=0,322) and RPE-Choroid (p=0,353).Conclusions : In sum, our results suggest that the formation of vascular tufts that are produced during the CNV is not mediated by the cooperative signalling between p75NTR and Trk receptors.