High-Dose Voclosporin Protects Against Acute Kidney Injury via Regnase-2-Mediated NGAL MRNA Decay.

Acute kidney injury (AKI) is a major complication of lupus nephritis and kidney transplantation, inevitably causing ischemia-reperfusion (I/R) injury. We previously confirmed that high-dose voclosporin induces drug nephropathy through aberrant peroxisome accumulation. The latter induces increased renal indole-3-aceticT acid (IAA) production due to the decreased expression of the IAA-degrading enzyme indolethylamine N-methyltransferase (INMT). Conversely, INMT overexpression prevents this nephropathy, suggesting that high-dose voclosporin could enable a novel therapeutic approach. This prompted us to test whether INMT overexpression with high-dose voclosporin could avert nephrotoxicity and protect against I/R injury. Inmt-overexpressing mice treated with high-dose voclosporin exhibited absence of peroxisomal abnormalities and resistance to I/R injury. RNA sequencing revealed the downregulation of tubular injury markers NGAL (Lcn2) and KIM-1 (Havcr1) concurrent with significant cytokine suppression. Mechanistic analysis revealed the robust induction of Regnase-2, an mRNA decay factor, which directly targeted stem-loop structures within the 3' untranslated region of Lcn2 and Havcr1, thereby promoting their degradation in proximal tubular cells. Importantly, Regnase-2 knockdown mice showed Lcn2 upregulation, mitochondrial dysfunction, and peroxisomal abnormalities culminating in AKI, underscoring its renal protective effects. High-dose voclosporin under Inmt overexpression promoted Regnase-2-mediated mRNA decay to suppress tubular injury. This protective effect extended beyond I/R to rhabdomyolysis- and lipopolysaccharide-induced AKI to prevent nephropathy. Our findings demonstrate the potential transformative therapeutic approach of administering high-dose voclosporin to promote the prophylactic effect of Regnase-2 augmentation against AKI in both native and transplanted human kidneys.