Upregulated FTO promotes TNIP1 m6A demethylation induced penile corpus cavernosum endothelial pyroptosis and erectile dysfunction in type 2 diabetic rats

BACKGROUND: Erectile dysfunction (ED) is a prevalent complication of type 2 diabetes mellitus (T2DM). However, the role of RNA N6-methyladenosine (m6A) methylation in T2DM-associated ED remains unclear. AIM: To determine whether m6A demethylation of TNFAIP3-interacting protein 1 (TNIP1) RNA mediated by fat mass and obesity-associated protein (FTO) regulates pyroptosis in corpus cavernosum endothelial cells in T2DM and contributes to ED. METHODS: The endothelial cells of the penile corpus cavernosum were obtained from Sprague-Dawley (SD) rats aged 8 weeks and assigned to five groups as follows: Control group, KD-FTO group that treated with the FTO-targeting siRNA lentivirus, OE-FTO group that treated with the FTO-overexpression lentiviral vector, KD-NC group that treated with the control siRNA lentivirus, and OE-NC group that treated with the empty FTO-overexpression lentiviral vector. The levels of FTO, TNIP1, NFκB, caspase-1, p-eNOS/eNOS, and NO were measured. TNIP1 mRNA stability was assessed. Male SD rats aged 8 weeks were randomly allocated to six groups: Control group, NC + Con group that SD rats treated with the empty lentivirus, NC + FTO-OE group that SD rats treated with the lentiviral vector carrying an over-expressed FTO gene, T2DM rats, T2DM + Con group that T2DM rats treated with the empty lentivirus, and T2DM + FTO-KD group that T2DM rats treated with the lentivirus carrying an siRNA targeting FTO. Two weeks after injection, the expression of FTO, TNIP1, caspase-1, p-eNOS/eNOS, as well as the ratio of pyroptotic endothelial cells in the penile corpus cavernosum, was evaluated. OUTCOMES: Upregulation of FTO in the penile corpus cavernosum of T2DM rats promoted m6A demethylation of TNIP1 mRNA, decreased TNIP1 expression, and enhanced the NFκB/caspase-1 pathway, thereby increasing endothelial pyroptosis and reducing ED. RESULTS: Compared with the NC group, the T2DM group exhibited significantly increased FTO expression, whereas global RNA m6A methylation, ICPmax/MAP, p-eNOS/eNOS, and NO levels were significantly decreased (P < .05). Compared with the T2DM group, the T2DM + FTO-KD group showed markedly higher TNIP1 levels, p-eNOS/eNOS, and ICPmax/MAP, accompanied by reduced expression of FTO, NFκB, caspase-1, and significantly lower pyroptotic endothelial cells (P < .05). CLINICAL IMPLICATIONS: Targeting FTO-mediated TNIP1 m6A demethylation may offer a therapeutic strategy for T2DM-associated ED. STRENGTHS AND LIMITATIONS: Other m6A regulators potentially involved in this process were not assessed. CONCLUSION: In T2DM, upregulated FTO promoted m6A demethylation of TNIP1 mRNA, downregulated TNIP1 expression, enhanced NFκB/caspase-1 signaling, and increased endothelial cell pyroptosis in the penile corpus cavernosum, thereby contributing to ED.