lnc-MRGPRF-6:1 Promotes ox-LDL-Induced Macrophage Ferroptosis via Suppressing GPX4.

BACKGROUND: Ferroptosis, a newly discovered mode of cell death, emerges as a new target for atherosclerosis (AS). Long noncoding RNAs (lncRNAs) are involved in the regulation of ferroptosis. In our previous study, lnc-MRGPRF-6:1 was highly expressed in patients with coronary atherosclerotic disease (CAD) and closely associated with macrophage-mediated inflammation in AS. In the present study, we aim to investigate the role of lnc-MRGPRF-6:1 in oxidized-low-density lipoprotein (ox-LDL)-induced macrophage ferroptosis in AS.

METHODS: Firstly, ox-LDL-treated macrophages were used to simulate macrophage injury in AS. Then, ferroptosis-related biomarkers and mitochondrial morphology were detected and observed in ox-LDL-treated macrophages. Subsequently, we constructed lnc-MRGPRF-6:1 knockdown and overexpression of THP-1-derived macrophages and investigated the role of lnc-MRGPRF-6:1 in ox-LDL-induced ferroptosis. Then human monocytes were isolated successfully and were used to explore the role of lnc-MRGPRF-6:1 in macrophage ferroptosis. Likely, we constructed lnc-MRGPRF-6:1 knockdown and overexpression of human monocyte-derived macrophages and detected the expression levels of ferroptosis-related biomarkers. Then, transcriptome sequencing, literature searching, and following quantitative real-time polymerase chain reaction and western blot were implemented to explore specific signaling pathway in the process. It was demonstrated that lnc-MRGPRF-6:1 may regulate ox-LDL-induced macrophage ferroptosis through glutathione peroxidase 4 (GPX4). Eventually, the correlation between lnc-MRGPRF-6:1 and GPX4 was measured in monocyte-derived macrophages of CAD patients and controls.

RESULTS: The ox-LDL-induced injury in macrophages was involved in ferroptosis. The knockdown of lnc-MRGPRF-6:1 could alleviate ox-LDL-induced ferroptosis in macrophages. Meanwhile, the overexpression of lnc-MRGPRF-6:1 could intensify ox-LDL-induced ferroptosis. Furthermore, the knockdown of lnc-MRGPRF-6:1 could alleviate the decrease of GPX4 induced by RAS-selective lethal compounds 3 (RSL-3). These indicated that lnc-MRGPRF-6:1 may suppress GPX4 to induce macrophage ferroptosis. Eventually, lnc-MRGPRF-6:1 was highly expressed in the monocyte-derived macrophages of CAD patients and was negatively correlated with the expression of GPX4.

CONCLUSION: lnc-MRGPRF-6:1 can promote ox-LDL-induced macrophage ferroptosis through inhibiting GPX4.