Knocking down macrophages Caspase-6 through HMGB1 coordinates macrophage trophoblast crosstalk to suppress ferroptosis and alleviate preeclampsia.

ABSTRACT

OBJECTIVE: Caspase-6 is an important regulatory factor in innate immunity, inflammasome activation, and host defense, but its role in preeclampsia (PE) is unknown. This study aims to investigate the mechanism of Caspase-6 in the interaction between PE rats and macrophage-trophoblast cells, in order to provide a new theoretical basis for the treatment of PE. METHODS: Co-cultures of THP-1 cells and HTR8/SVneo cells were employed to investigate the HMGB1 signaling in macrophages (transfection with si-Caspase-6) and HTR8/SVneo cells. The PE rat model was constructed by using the reduced uterine perfusion pressure (RUPP) surgery to explore the therapeutic effects of bone marrow-derived macrophages (BMDM) transfected with si-Caspase-6 in PE rats. ELISA, Western blot, immunofluorescence, etc., were employed to characterize the expression of ferroptosis-related markers. RESULTS: Caspase-6 expression was significantly increased in CD14+ macrophages in the placental tissue of PE rats. Overexpression of Caspase-6 in THP-1 cells induced ferroptosis of HTR8/SVneo cells, but this process was blocked by anti-HMGB1 neutralizing antibody. Knockdown of Caspase-6 in macrophages could alleviate ferroptosis of HTR8/SVneo cells and restore its basic characteristics. Knockdown of Caspase-6 in BMDM downregulated ferroptosis in placental tissue of PE rats through HMGB1, thereby improving the disease phenotype in rats. CONCLUSION: Knocking down Caspase-6 in BMDM regulated the crosstalk between macrophages and HTR8/SVneo cells through HMGB1, inhibiting HTR8/SVneo cell ferroptosis, thereby improving adverse pregnancy outcomes of PE.