Melatonin regulates trophoblast pyroptosis, invasion and migration in preeclampsia by inhibiting HtrA1 transcription through the microRNA‐520c‐3p/SETD7 axis

Abstract Objective Melatonin has an inhibitory effect on preeclampsia (PE). This study was launched to explore the way that melatonin regulated trophoblast migration, invasion, and pyroptosis in PE and to provide new ideas for the diagnosis and treatment of PE. Methods Expression levels of melatonin receptors (MT1 and MT2), microRNA (miR)‐520c‐3p, SETD7, and HtrA1 in placental tissues and HTR8/SVneo cells were measured by RT‐qPCR and Western blot. Scratch, Transwell, and Western blot assays were performed to detect migration, invasion, and pyroptosis of hypoxia/reoxygenation (H/R)‐treated HTR8/SVneo cells. Dual‐luciferase reporter assay was utilized to verify the targeting relationship between miR‐520c‐3p and SETD7. ChIP experiment was conducted to detect the enrichment of H3K4me3 and SETD7 in HtrA1 promoter. Results Low expression of MT1, MT2, and miR‐520c‐3p and high expression of SETD7 and HtrA1 were observed in the placental tissues of PE patients and H/R‐treated HTR8/Svneo cells. A high concentration of melatonin promoted migration and invasion and inhibited pyroptosis of PE cell models. Knockdown of miR‐520c‐3p, overexpression of SETD7, or overexpression of HtrA1 impaired migration and invasion and accelerated pyroptosis of H/R‐treated HTR8/SVneo cells, but these outcomes could be reversed by treatment with 1000 μM melatonin. miR‐520c‐3p targeted SETD7 which promoted histone methylation in the promoter region of HtrA1. Conclusion Melatonin may inhibit HtrA1 transcription through the miR‐520c‐3p/SETD7 axis to promote trophoblast invasion and migration and reduce trophoblast pyroptosis in PE.