METTL3 mediates Ang-II-induced cardiac hypertrophy by regulating KLF5 expression in an m⁶A-dependent manner

Cardiac hypertrophy is a pivotal pathological process leading to heart failure, driven by chronic stress, pressure overload, and neurohormonal stimulation, such as Angiotensin II (Ang II). Although METTL3-mediated m⁶A modification has been implicated in cardiovascular diseases, the precise role and underlying mechanism of the KLF5 in Ang II-induced myocardial hypertrophy remain poorly understood.

H9C2 and AC16 cardiomyocytes were treated with Ang II to establish an in vitro hypertrophy model. The expression of METTL3, KLF5, and hypertrophic markers (ANP, BNP, and β-MHC) was quantified using RT-qPCR and Western blot. Functional validation was performed via lentiviral-mediated knockdown and overexpression. The direct interaction and m⁶A modification of KLF5 mRNA were validated using RIP-qPCR and MeRIP-qPCR assays. Cardiomyocyte surface area and α-actinin distribution were assessed by immunofluorescence. mRNA stability was determined by Actinomycin D assays.

Ang II stimulation significantly upregulated the expression of METTL3 and KLF5 in a dose-dependent manner. Silencing of either METTL3 or KLF5 effectively attenuated Ang II-induced cardiomyocyte enlargement and suppressed the fetal gene program. Mechanistically, METTL3 was found to promote KLF5 expression by increasing its m⁶A modification levels and enhancing its mRNA stability. Furthermore, rescue experiments demonstrated that the inhibitory effect of METTL3 knockdown on cardiomyocyte hypertrophy was substantially reversed by KLF5 overexpression, confirming that KLF5 is a functional downstream effector of METTL3.

METTL3 facilitates Ang II-induced cardiac hypertrophy by modulating KLF5 expression through an m⁶A-dependent mechanism. Targeting the METTL3/KLF5 axis may offer a novel therapeutic strategy for the treatment of pathological myocardial hypertrophy.