<scp>ARIH1</scp> Promotes Preeclampsia by Inducing <scp>MFN2</scp> ‐Dependent Hypoxia‐Triggered Mitophagy and Endoplasmic Reticulum Stress in Trophoblasts

The pathogenesis of preeclampsia (PE) involves endoplasmic reticulum stress (ERS) and the subsequent induction of mitophagy. Ariadne RBR E3 ubiquitin protein ligase 1 (ARIH1) is a key factor regulating mitophagy, but its role in PE has not been reported. In this study, we aimed to analyze the role of ARIH1 in the pathogenesis of PE. The role of ARIH1 in the pathogenesis of PE was investigated in a PE rat model and in an in vitro hypoxia/reoxygenation (H/R) model using HTR8 trophoblast cells. The study revealed that ARIH1 was upregulated while Mitochondrial fusion protein 2 (MFN2) was downregulated in PE rats and H/R-treated HTR8 cells. Inhibition of ARIH1 reversed the suppressed proliferation and invasion capacities of HTR8 cells under H/R conditions, reduced intracellular reactive oxygen species (ROS) and calcium ions (Ca²⁺), and modulated the protein expression of LC3II/LC3I, p62, glucose-regulatory protein 78 (GRP78), and C/EBP homologous protein (CHOP). Additionally, mitochondrial membrane potential was improved. Interestingly, treatment with Tunicamycin or Thapsigargin could reverse the inhibitory effects of ARIH1 downregulation on trophoblastic cells by activating endoplasmic reticulum stress (ERS) and mitophagy. Notably, the study identified for the first time that ARIH1 mediates the ubiquitination degradation of MFN2. Inhibition of MFN2 abolished the regulatory effects of ARIH1 downegulation on ERS and mitophagy in trophoblast cells, as well as the associated damage in PE rats. Overall, the findings underscore the crucial role of ARIH1 in regulating mitophagy and ERS through MFN2, highlighting its significance in the pathogenesis of PE.