FTO alleviates Aβ1-40 induced retinal pigment epithelium degeneration via PKA/CREB signaling pathway

Abstract Background Amyloid-β (Aβ), a component of age-related macular degeneration (AMD) hallmark drusen, induces retinal pigment epithelium (RPE) cell degeneration and promotes the progress of AMD. Evidence shows that epigenetics mechanism is involved in the regulation of AMD. In this study, we aimed to investigate the roles of N6-methyladenosine (m6A) and its demethylase the fat mass and obesity-associated gene (FTO) in Aβ-mediated degeneration. Methods The molecular characteristics and morphology of FTO were examined by quantitative Real-Time PCR (qRT-PCR), Western blot and immunofluorescence. Inhibition of FTO was conducted to analyze its function on cell survival. Ocular Coherence Tomography and Fundus Photography was performed to evaluate the fundus of animal models. m6A-mRNA Epi-transcriptomic microarray, bioinformatics analysis and experimental verification were used to explore the potential molecular mechanism and signaling pathway. Results We found overexpression of FTO in Aβ model and demonstrated that inhibition of FTO by the sodium form of Meclofenamic acid (MA1) aggravated RPE impairment. Mechanistically, we identified protein kinase A (PKA) as FTO’s mediating target and found that FTO epigenetically demethylated PKA mRNA and decreased PKA expression, leading to suppressed PKA/ cyclin AMP-responsive element binding (CREB) signaling pathway. Moreover, inhibition of FTO promoted PKA/CREB signaling pathway inducing greater RPE degeneration and death. Conclusions These data demonstrated the functional significance of FTO in Aβ-induced RPE degeneration and the regulatory mechanism of PKA/CREB signaling pathway, implying FTO as a potentially therapeutic target for AMD.