TET3-mediated novel regulatory mechanism affecting trophoblast invasion and migration: Implications for preeclampsia development

Introduction: Aberrant expression of genes has been demonstrated to be related to the abnormal function of trophoblasts and lead to the occurrence and progression of Preeclampsia (PE). However, the underlying mechanism of PE has not been elucidated. Methods: We performed PCR analysis to investigate TET3 expression in PE placental tissues. Cell assays were performed in HTR-8/SVneo and JAR. Cell invasion and migration events were investigated by transwell assays in vitro. ChIP-PCR and Targeted bisulfite sequencing were conducted to detect the demethylation of related CpG sites in the KLF13 promoter after inhibition of TET3. In conjunction with bioinformatics analysis, luciferase reporter assays were performed to elucidate the mechanism by which miR-544 binds to TET3/KLF13 mRNA. Results: In this study, we identified genes associated with human extravillous trophoblasts by conducting sc-seq analysis from the GEO. Then, we measured the expression of TET3 in a larger clinical sample. The results showed that TET3, a DNA demethylase, was found to be expressed at much higher levels in the preeclamptic placenta compared to the control. Then, the inhibition of TET3 significantly promoted trophoblast cell migration and invasion. Conversely, TET3 overexpression suppressed cell migration and invasion in vitro. Further RNA sequencing and mechanism analysis indicated that the inhibition of TET3 suppressed the activation of KLF13 by reducing the demethylation of related CpG sites in the KLF13 promoter, thereby transcriptionally inactivating KLF13 expression. Moreover, luciferase reporter assay indicate that TET3 and KLF13 were direct targets of miR544. Discussion: This study uncovers a TET3-mediated regulatory mechanism in PE progression and suggests that targeting the placental miR-544-TET3-KLF13-axis might provide new diagnostic and therapeutic strategies for PE.