Lysine-specific demethylase 1 aggravated oxidative stress and ferroptosis induced by renal ischemia and reperfusion injury through activation of TLR4/NOX4 pathway in mice.

Acute kidney injury (AKI) is mainly caused by renal ischaemia reperfusion injury (IRI). Lots of evidence suggests that ferroptosis and oxidative stress play the vital role in renal IRI. However, the specific mechanism of renal IRI has not been fully elucidated. lysine-specific demethylase 1 (LSD1) has been shown to regulate the pathogenesis of kidney disease. In this study, we firstly found that LSD1 was positively related to renal IRI. TCP, a classical LSD1 inhibitor, could alleviate tissue damage induced by renal IRI. Inhibition of LSD1 with either TCP or LSD1 knockdown could alleviate ferroptosis and oxidative stress caused by IRI both in vivo and in vitro. Furthermore, the results showed that suppression of LSD1 decreased the expression of TLR4/NOX4 pathway in HK-2 cells subjected to H/R. With the si-RNA against TLR4 or NOX4, it showed that the silence of TLR4/NOX4 reduced oxidative stress and ferroptosis in vitro. Moreover, to demonstrate the crucial role of TLR4/NOX4, TLR4 reduction, mediated by inhibition of LSD1, was compensated through delivering the adenovirus carrying TLR4 in vitro. The results showed that the compensation of TLR4 blunted the alleviation of oxidative stress and ferroptosis, induced by LSD1 inhibition. Further study showed that LSD1 activates TLR4/NOX4 pathway by reducing the enrichment of H3K9me2 in the TLR4 promoter region. In conclusion, our results demonstrated that LSD1 inhibition blocked ferroptosis and oxidative stress caused by renal IRI through the TLR4/NOX4 pathway, indicating that LSD1 could be a potential therapeutic target for renal IRI.