ABSTRACT: Diabetic retinopathy (DR), a leading cause of irreversible vision loss in the working-age population, is an inflammatory, neuro-vascular complication of diabetes with poorly understood mechanism. N6-methyladenosine (m6A) modification plays crucial roles in biological and pathological events, while its role in DR remain elusive. Herein, we identified the pathological involvement of m6A demethylase FTO in DR. FTO expression was elevated in proliferative membranes of DR patients, endothelial cells (EC) under diabetic stress, and retinal vessels of diabetic murine models. FTO overexpression in EC promoted EC cycle progression and tip cell formation to facilitate angiogenesis in vitro, in mice and in zebrafish. FTO also regulated EC-pericyte crosstalk to trigger diabetes-induced microvascular leakage, and mediated EC-microglia crosstalk to induce retinal inflammation and subsequent neurodegeneration in vivo and in vitro. Mechanistically, FTO regulated EC features depending on its demethylation activity via modulating CDK2 mRNA stability with YTHDF2 as the reader. Moreover, FTO up-regulation in EC under diabetic conditions was driven by lactic acid mediated histone lactylation. FB23-2, which inhibits FTO’s m6A demethylase activity, suppressed diabetes associated endothelial phenotypes in vitro and in vivo. Noteworthy, we developed a novel macrophage membrane coated and PLGA-Dil based nanoplatform encapsulating FB23-2 for systemic administration, and confirmed its targeting and therapeutic efficacy in mice. Collectively, our study demonstrated an FTO-mediated regulatory network that coordinates EC biology and retinal homeostasis in DR, providing a promising nanotherapeutic approach for DR treatment. Diabetic retinopathy (DR), a leading cause of irreversible vision loss in the working-age population, is an inflammatory, neuro-vascular complication of diabetes with poorly understood mechanism. N6-methyladenosine (m6A) modification plays crucial roles in biological and pathological events, while its role in DR remain elusive. Herein, we identified the pathological involvement of m6A demethylase FTO in DR. FTO expression was elevated in proliferative membranes of DR patients, endothelial cells (EC) under diabetic stress, and retinal vessels of diabetic murine models. FTO overexpression in EC promoted EC cycle progression and tip cell formation to facilitate angiogenesis in vitro, in mice and in zebrafish. FTO also regulated EC-pericyte crosstalk to trigger diabetes-induced microvascular leakage, and mediated EC-microglia crosstalk to induce retinal inflammation and subsequent neurodegeneration in vivo and in vitro. Mechanistically, FTO regulated EC features depending on its demethylation activity via modulating CDK2 mRNA stability with YTHDF2 as the reader. Moreover, FTO up-regulation in EC under diabetic conditions was driven by lactic acid mediated histone lactylation. FB23-2, which inhibits FTO’s m6A demethylase activity, suppressed diabetes associated endothelial phenotypes in vitro and in vivo. Noteworthy, we developed a novel macrophage membrane coated and PLGA-Dil based nanoplatform encapsulating FB23-2 for systemic administration, and confirmed its targeting and therapeutic efficacy in mice. Collectively, our study demonstrated an FTO-mediated regulatory network that coordinates EC biology and retinal homeostasis in DR, providing a promising nanotherapeutic approach for DR treatment.
