Novel Sigma-1 receptor agonist alleviates renal ischemic injury by targeting apoptotic and inflammatory pathways

Renal ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury, yet its mechanisms remain unclear, and effective treatments are lacking. We previously showed that the Sigma-1 receptor (S1R) agonist fluvoxamine protects against IRI and IRI-induced graft injury during transplantation. Here, we developed a novel compound, 'VCC904125', with potent S1R affinity and minimal blood-brain barrier penetration to mitigate renal IRI without psychoactive side effects. Mice were treated with VCC904125 before clamping the left renal pedicles, followed by contralateral nephrectomy. VCC904125 markedly alleviated BUN and serum creatinine levels, KIM-1 and NGAL expression, and structural damage at both 24 and 48 h after reperfusion. S1R activation by VCC904125 targets key pathways underlying IRI, including apoptosis and inflammation. VCC904125 treatment impeded the apoptotic p53-Bax pathway and influenced CaMKII-NF-κB signaling, resulting in diminished proinflammatory cytokine expression. In the ex vivo model, kidneys were perfused and stored in an HTK preservation solution supplemented with VCC904125 to simulate cold storage conditions before transplantation. VCC904125 ameliorated structural injury profoundly after cold ischemia. Taken together, S1R activation by VCC904125 decreases renal IRI via ameliorating apoptotic and inflammatory pathways. These results highlight the therapeutic promise of S1R activation in mitigating cold and warm ischemia and improving transplant outcomes.