LncRNA MALAT1 affects the migration and invasion of trophoblast cells by regulating FOS expression in early-onset preeclampsia

Background: Preeclampsia (PE), particularly early-onset PE (ePE), causes maternal and fetal complications and remains a major health problem in modern society. Aberrant uterine spiral artery remodeling leads to ePE through poor placentation. In this study, we investigated the role of the long non-coding RNA (lncRNA) MALAT1 in ePE pathogenesis. Methods: Total RNA was extracted from 40 paired placental ePE tissues and control groups. RNA levels were quantified by qRT-PCR and protein expression was determined by western blot and immunohistochemistry (IHC) analysis. The effects of MALAT1 on trophoblast migration and invasion were evaluated in HTR-8/SVneo and JAR cells. FOS was identified as a downstream functional gene of MALAT1 by RNA-seq. RNA binding protein immunoprecipitations (RIPs) were performed to reveal the cellular targets of MALAT1. Results: MALAT1 was poorly expressed in ePE placentas and its silencing (-/-) inhibited trophoblast invasion and migration. MALAT1 -/- also decreased N-cadherin and vimentin expression, but increased E-cadherin expression. RNA-seq analysis and subsequent RIP assays showed that MALAT1 improved FOS through Hu-antigen R (HuR) binding. FOS overexpression similarly enhanced trophoblast migration and invasion. IHC staining showed that E-cadherin was upregulated in placenta tissue from ePE groups, whilst FOS, N-cadherin, and vimentin were downregulated. Conclusion: MALAT1 promotes trophoblast migration and invasion through FOS-induced epithelial mesenchymal transition (EMT). This highlights new roles for MALAT1 in the impairment of spiral artery remodeling in ePE pathogenesis.