Meclofenamic acid promotes cisplatin-induced acute kidney injury by inhibiting fat mass and obesity-associated protein-mediated m6A abrogation in RNA

Abstract

The role of RNA methylation on the sixth N atom of adenylate (m⁶A) in acute kidney injury (AKI) is unknown. FTO (fat mass and obesity-associated protein) reverses the m⁶A modification in cisplatin-induced AKI. Here, we aimed to determine FTO's role in AKI. We induced AKI in c57BL/6 mice by intraperitoneal cisplatin injection and treated the animal with vehicle or an FTO inhibitor meclofenamic acid (MA) for 3 days. Moreover, as an in vitro model, human kidney proximal tubular cells (HK2 cells) were treated with cisplatin. We found that the cisplatin treatment reduces FTO expression and increases m⁶A levels in vivo and in vitro MA aggravated renal damage and increased apoptosis in cisplatin-treated kidneys, phenotypes that were correlated with reduced FTO expression and increased m⁶A levels. Moreover, MA promoted apoptosis in cisplatin-treated HK2 cells, which was correlated with the reduced FTO expression and increased m⁶A in HK2 cells. FTO protein overexpression reduced m⁶A levels and inhibited apoptosis in cisplatin-treated HK2 cells and also blocked the MA-induced increase in m⁶A levels and apoptosis rates. In agreement, overexpression of the m⁶A-generating methyltransferase-like 3 and 14 (METTL3 and METTL14) or siRNA-mediated FTO knockdown promoted apoptosis and enhanced m⁶A levels in cisplatin-treated HK2 cells. MA increased p53 mRNA and protein levels in AKI both in vitro and in vivo, and FTO overexpression reduced p53 expression and reversed the MA-induced p53 increase in AKI. In conclusion, reduced renal FTO expression in cisplatin-induced AKI increases RNA m⁶A levels and aggravates renal damages.

Keywords: Fat mass and obesity-associated protein, FTO; N6-methyladenosine, m6A; RNA methylation; RNA modification; acute kidney injury, AKI; apoptosis; caspase; cell signaling; cisplatin; kidney; p53.