Serum from Antiphospholipid Syndrome Patients Downregulates Endothelial lncRNAs HIF1A-AS1 and OIP5-AS1

This study aimed to evaluate whether serum from patients with primary antiphospholipid syndrome (APS) is associated with changes in the expression of long non-coding RNAs (lncRNAs) in endothelial cells. Human umbilical vein endothelial cells (HUVECs) were cultured with serum from 12 female patients with APS or 8 age-matched healthy female controls. The expression levels of HIF1A-AS1, OIP5-AS1, and GAS5 were quantified by RT-qPCR. Exposure of HUVECs to APS serum was associated with reduced expression of HIF1A-AS1 and OIP5-AS1 compared with cells stimulated with control serum. The median HIF1A-AS1 expression levels were 0.08 a.u. (interquartile range, 0.06–0.10) in APS-stimulated cells versus 0.14 a.u. (0.08–0.16) in controls (p = 0.044). Likewise, OIP5-AS1 levels were 0.09 a.u. (0.01–0.16) in APS-stimulated cells versus 2.24 a.u. (0.70–3.55) in controls (p = 0.018). In contrast, GAS5 expression did not differ significantly between groups (340 a.u. (310–3940 versus 358 a.u. (163–445); p = 0.290). In this proof-of-concept study, serum from APS patients was associated with selective downregulation of HIF1A-AS1 and OIP5-AS1 in endothelial cells. These findings support a potential link between circulating APS-related factors and endothelial lncRNA expression; however, no mechanistic or functional conclusions can be drawn.