Nrf1 deficiency promotes tubular ferroptosis by regulating ACSL4 in cisplatin-induced acute kidney injury

Nrf1 is a transcription factor that is highly conserved and reacts to oxidative, proteotoxic and endoplasmic reticulum stress in cells; nonetheless, its function in the context of acute kidney injury (AKI) remains unclear. Using a model of cisplatin-induced nephrotoxicity in vitro and in vivo, we found that the expression of Nrf1, which is expressed at high levels in renal tubular cells, was significantly downregulated after cisplatin treatment. Proximal tubule-specific Nrf1 knockout worsened and Nrf1 overexpression attenuated cisplatin-induced (CI)-AKI. RNA sequencing analysis revealed that Nrf1 overexpression decreased the number of transcripts involved in cell death, specifically those associated with ferroptosis, after cisplatin treatment. Furthermore, ferroptosis responses, characterized by increased lipid peroxidation and iron content and decreased FPN, XCT and glutathione peroxidase 4 levels, were attenuated in Nrf1-overexpressing HK-2 cells but worsened in Nrf1-knockout mice and Nrf1-knockdown HK-2 cells. Moreover, lipidomic and RNA sequencing results indicated that Nrf1 regulated the levels of polyunsaturated fatty acids (PUFAs) and inhibited the expression of ACSL4. Additionally, ChIP experiments revealed that Nrf1 bound to the promoter region of ACSL4, thereby inhibiting its transcription. Furthermore, inhibitors of ACSL4 significantly reduced the sensitivity of HK-2 cells to ferroptosis induced by Nrf1 knockdown. Collectively, these findings suggest that Nrf1 is a novel target for inhibiting ferroptosis in renal tubule cells by suppressing the transcription and expression of ACSL4, thereby reducing PUFA levels. Consequently, activators developed for Nrf1 may hold therapeutic potential in the treatment of patients with CI-AKI.