Downregulation of LINC00221 promotes angiopoiesis in HUVEC and inhibits recruitment of macrophages by augmenting miR-542-3p in trophoblast cells

To investigate the effects of long intergenic non-protein coding RNA 221 (LINC00221) on preeclampsia (PE) and its mechanism. The expression of LINC00221 was detected in placental tissues from PE patients and normal pregnant women (non-PE). Next, the effects of LINC00221 silencing on trophoblast cells (HTR-8/SVneo and JEG-3) and co-cultured HUVECs or macrophages were evaluated. Afterwards, miR-542-3p was confirmed to bind to LINC00221 directly, and miR-542-3p mimics and inhibitors were transfected into trophoblast cells. Next, a rescue experiment was performed to examine the effect of LINC00221/miR-542-3p axis. Finally, the effect of LINC00221 was also verified in vivo in rat PE models. The expression of LINC00221 was higher in placental tissues of PE patients than those of non-PE. LINC00221 silencing significantly reduced MCP1 level and increased the VEGF level in trophoblast cells. LINC00221 knockdown in trophoblast cells remarkably enhanced VEGFR expression and the angiopoiesis of HUVECs, and decreased the migration and invasion of macrophages and reduced TNF-α level. Besides, LINC00221 knockdown decreased CHOP, p-IREα, p-PERK, and iNOS expression and increased Trx expression. Notably, LINC00221 negatively regulated miR-542-3p expression. MiR-542-3p overexpression had an effect to that of LINC00221 knockdown, while miR-542-3p inhibition had the opposite effect. Treatment with miR-542-3p inhibitors partially reversed the protective effect of LINC00221 silencing. PE rat model results were consistent with those of in vitro experiments. Downregulation of LINC00221 might reduce dysfunction, inflammatory responses, endoplasmic reticulum stress, and oxidative stress, and thereby protect against PE by augmenting miR-542-3p.