Amyloid-β (Aβ) is thought to be a critical pathologic factor of retinal pigment epithelium (RPE) degeneration in
age-related macular degeneration (AMD). Aβ induces inflammatory responses in RPE cells and recent studies demonstrate the
N6-methyladenosine (m6A) regulatory role in RPE cell
inflammation.
m6A is a reversible epigenetic posttranslational modification, but its relationship with Aβ-induced RPE degeneration is yet to be thoroughly investigated. The present study explored the role and mechanism of
m6A in Aβ-induced RPE degeneration model. This model was induced via intravitreally injecting oligomeric Aβ and the morphology of its retina was analyzed. One of
m6A demethylases, the fat mass and
obesity-associated (FTO) gene expression, was assessed. An m6A-messenger
RNA (
mRNA) epitranscriptomic microarray was employed for further bioinformatic analyses. It was confirmed that Aβ induced FTO upregulation within the RPE.
Hypopigmentation alterations and structural disorganization were observed in Aβ-treated eyes, and inhibition of FTO exacerbated
retinal degeneration and RPE impairment. Moreover, the m6A-mRNA epitranscriptomic microarray suggested that
protein kinase A (PKA) was a target of FTO, and the PKA/
cyclic AMP-responsive
element binding (CREB) signaling pathway was involved in Aβ-induced RPE degeneration. m6A-RNA
binding protein immunoprecipitation confirmed that FTO demethylated PKA within the RPE cells of Aβ-treated eyes. Altered expression of PKA and its downstream targets (CREB and
brain-derived neurotrophic factor) was confirmed by quantitative reverse-transcription polymerase chain reaction and Western blot analyses. Hence, this study's findings shed light on FTO-mediated
m6A modification in Aβ-induced RPE degeneration and indicate potential therapeutic targets for AMD.