Inhibition of ferroptosis-related NCF2 blocks the progression of lupus nephritis by activating PPARα pathway.

Abstract

Background: Ferroptosis is involved in the pathogenesis of Lupus nephritis (LN), but its mechanism of action in LN remains unknown. This study aims to explore the effect of the ferroptositic-related gene neutrophil cytosolic factor 2 (NCF2) on LN and its potential downstream mechanism.

Method: Differentially expressed genes (DEGs) between LN tissues and control tissues were screened out using "limma" R package. Weighted gene co-expression network analysis (WGCNA) was used to identify the key modules related to inflammation in LN based on DEGs. The genes associated with ferroptosis were obtained from the FerrDb database. Support vector machine recursive feature elimination (SVM-RFE) was used to screen candidate key genes. The expression and the diagnostic ability of candidate key genes was evaluated using an external validation set. Immune infiltration analysis was performed using CIBERSORT. Gene set enrichment analysis was used to reveal the molecular mechanisms of key genes. A cell model of LN was constructed using lipopolysaccharide (LPS) -induced human renal cortical proximal tubule epithelial cells HK-2 to explore the potential functions and mechanisms of the key gene NCF2 in LN.

Result: Nine ferroptosis-related genes in LN were obtained after cross-analysis, and six candidate genes were screened out using machine learning approach. Among them, NCF2 was identified as a key gene related to ferroptosis in LN. The expression of NCF2 was positively correlated with the infiltration levels of pro-inflammatory cells such as monocytes and M1 macrophages, and negatively correlated with those of anti-inflammatory cells such as regulatory T cells (Tregs). NCF2-related DEGs were significantly enriched in the peroxisome proliferator-activated receptor (PPAR) signaling pathway. In vitro experiments demonstrated that knocking down NCF2 significantly inhibited LPS-induced suppression of viability, apoptosis, inflammatory response and ferroptosis of HK-2 cells. NCF2 knockdown also inhibited ferroptosis by activating the PPARα pathway.

Conclusion: NCF2 is a key regulatory factor of LN. Its knockdown inhibits ferroptosis by activating the PPARα signaling, thereby alleviating inflammatory injury of renal tubular epithelial cells. Targeting NCF2 may provide a new strategy for the treatment of LN.