Roles and action mechanisms of NRIP1 in pre-eclampsia

Pre-eclampsia (PE) is characterized by the onset of hypertension and proteinuria during pregnancy. Here, we aimed to explore the functions of nuclear receptor-interacting protein 1 (NRIP1) in PE mice and human placental JEG-3 cells. We evaluated its effects on JEG-3 cell proliferation, apoptosis, invasion, and inflammatory response and regulation of Wnt/β-catenin pathway.

NRIP1 levels in human serum and placental tissues, JEG-3 cells, and mouse models were assessed via quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting. JEG-3 cell growth, apoptosis, migration, and invasion were evaluated via 5-ethynyl-2'-deoxyuridine, flow cytometry, and transwell assays. Levels of the inflammatory factors, matrix metalloproteinase (MMP)-2, tumor necrosis factor (TNF)-α, and interleukin (IL)-6, were determined via enzyme-linked immunosorbent assay. Wnt/β-catenin pathway was assessed via western blotting and qRT-PCR. Systolic blood pressure and proteinuria were measured using the non-invasive tail cuff method and Coomassie brilliant blue assay, respectively. TdT-mediated dUTP nick-end labeling assay was used to assess cell apoptosis in the placental tissues of PE mice.

NRIP1 levels were upregulated in the serum and placental tissues of patients with PE. In vitro experiments revealed that NRIP1-small interfering RNA (siRNA) increased the cell viability, migration, and invasion and reduced the cell apoptosis compared to the control siRNA. Moreover, NRIP1-siRNA activated the Wnt/β-catenin signaling pathway, as indicated by the increased Wnt3a, β-catenin, p-glycogen synthase kinase-3β, c-Myc, and cyclin D1 levels. Levels of the inflammatory factors, IL-6, TNF-α, and MMP-2, were decreased in the NRIP1-siRNA-treated group. Notably, NRIP1 downregulation improved the PE-like symptoms, inhibited the inflammatory responses, and reduced apoptosis in PE mice.

This study revealed the crucial roles of NRIP1 in PE. Our findings revealed that NRIP1 downregulation relieved PE symptoms by inhibiting cell proliferation, migration, and invasion via the Wnt/β-catenin pathway, thus providing a novel candidate for PE treatment.