The piRNA CHAPIR is identified as the upstream of METTL3.331CHAPIR regulates cardiac hypertrophy by interacting with METTL3 and inhibiting its methylase activity, leading to the hypomethylation of the ADP-ribosyltransferase Parp10 mRNA and the inhibition of YTHDF2-mediated degradation. This evidence concerns the gene METTL3 and cardiac hypertrophy.