MALAT1 modulates granulosa cells ferroptosis and apoptosis through PAK2 upregulation in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a complicated endocrinological disorder. We investigated the ferroptosis-regulated role of MALAT1 and its potential modulatory mechanisms in granulosa cells (GCs). Reverse transcripton quantitative polymerase chain reaction (RT-qPCR) was used to measure the relative expression of MALAT1/miR-155-5p/PAK2 in KGN cells after transfection. Online bioinformatic analysis was performed to predict the interactions between MALAT1/PAK2 and miR-155-5p. Dual luciferase assays were performed for relative luciferase activity in cell groups co-transfected with the pmiRGLO plasmids containing wild type (wt) or mutant type (mt) of MALAT1 (MALAT1-wt, MALAT1-mt), siRNA targeting MALAT1(si-MALAT1) miR-155-5p inhibitor or their control was transfected into KGN cells using Lipofectamine 2000. After 48 h, the transfected cells were collected for the following experiments. Cell viability and apoptosis were measured using Cell Counting Kit-8 (CCK-8) and flow cytometry. Malondialdehyde (MDA) level and reduced glutathione (GSH) / oxidized glutathione disulfide (GSSG) ratio were detected using commercial kits. Western blot was used to measure the relative protein changes in PAK2, SLC7A11 and GPX4. Knockdown of MALAT1 decreased cell viability, increased apoptosis and ferroptosis, which was reversed by miR-155-5p inhibition. MALAT1 downregulation inhibited PAK2, while miR-155-5p inhibition activated PAK2. The increase of relative luciferase activity in cells transfected with MALAT1-wt or PAK2-wt and miR-155-5p inhibitor suggests the bindings between miR-155-5p and MALAT1 or PAK2. This study revealed a novel ferroptosis-modulated role of MALAT1 in PCOS in vitro via interactions with miR-155-5p/PAK2. Further in vivo and clinical studies are needed to validate these in vitro findings and fully assess the therapeutic potential of MALAT1 in PCOS.