Inhibition of <i>METTL3</i> attenuates renal injury and inflammation by alleviating <i>TAB3</i> m6A modifications via IGF2BP2-dependent mechanisms

Abstract

The role of <i>N</i>⁶-methyladenosine (m6A) modifications in renal diseases is largely unknown. Here, we characterized the role of <i>N</i>⁶-adenosine-methyltransferase-like 3 (METTL3), whose expression is elevated in renal tubules in different acute kidney injury (AKI) models as well as in human biopsies and cultured tubular epithelial cells (TECs). <i>METTL3</i> silencing alleviated renal inflammation and programmed cell death in TECs in response to stimulation by tumor necrosis factor-α (TNF-α), cisplatin, and lipopolysaccharide (LPS), whereas <i>METTL3</i> overexpression had the opposite effects. Conditional knockout of <i>METTL3</i> from mouse kidneys attenuated cisplatin- and ischemic/reperfusion (I/R)-induced renal dysfunction, injury, and inflammation. Moreover, <i>TAB3</i> [TGF-β-activated kinase 1 (MAP3K7) binding protein 3] was identified as a target of METTL3 by m6A methylated RNA immunoprecipitation sequencing and RNA sequencing. The stability of <i>TAB3</i> was increased through binding of IGF2BP2 (insulin-like growth factor 2 binding protein 2) to its m6A-modified stop codon regions. The proinflammatory effects of TAB3 were then explored both in vitro and in vivo. Adeno-associated virus 9 (AAV9)-mediated <i>METTL3</i> silencing attenuated renal injury and inflammation in cisplatin- and LPS-induced AKI mouse models. We further identified Cpd-564 as a METTL3 inhibitor that had better protective effects against cisplatin- and ischemia/reperfusion-induced renal injury and inflammation than <i>S</i>-adenosyl-l-homocysteine, a previously identified METTL3 inhibitor. Collectively, METTL3 promoted m6A modifications of <i>TAB3</i> and enhanced its stability via IGF2BP2-dependent mechanisms. Both genetic and pharmacological inhibition of METTL3 attenuated renal injury and inflammation, suggesting that the METTL3/TAB3 axis is a potential target for treatment of AKI.