Neuroprotective Effects of lncRNA EPB41L4A-AS1 Against Ischemic Stroke Injury Through Regulating Microglial State...

Long non-coding RNAs (lncRNAs) regulate microRNAs and their target genes to control key pathological processes after acute ischemic stroke (AIS). To investigate lncRNA EPB41L4A-AS1's role in microglial function via miR-214-3p/GPX4, and its clinical relevance as a prognostic indicator in AIS. EPB41L4A-AS1 levels were measured by RT-qPCR in 120 AIS patients and OGD/R-treated BV2 microglia. ELISA and western blot were employed to assess microglial state transition and ferroptosis in OGD/R-injured BV2 cells. A combination of RIP, RNA pull-down, and luciferase reporter assays were employed to validate the miRNA and gene targets regulated by EPB41L4A-AS1. Functional rescue assays were conducted by co-transfecting miR-214-3p with GPX4 to validate the regulatory relationship in vitro. EPB41L4A-AS1 was significantly downregulated in the serum of AIS patients, with lower levels predicting worse prognosis. Elevated EPB41L4A-AS1 expression substantially reduced pro-inflammatory markers (iNOS, TL-1β and TNF-α), but enhanced anti-inflammatory markers (Arg1 and IL-10) of OGD/R-injured BV2 cells. Meanwhile, the iron overload and lipid peroxidation in OGD/R cells were also improved. RIP, RNA pull-down, and luciferase reporter assays confirmed the specific binding of miR-214-3p to EPB41L4A-AS1 and GPX4. Upon EPB41L4A-AS1 overexpression, miR-214-3p mimic amplified the iron overload and oxidative stress and led to a pro-inflammatory state of BV2 cells under OGD/R conditions. Restoring GPX4 expression abrogated these observed effects. Lower serum EPB41L4A-AS1 correlates with poor prognosis in AIS patients. The mechanism underlying its neuroprotective effects against microglial state transition and ferroptosis was delineated through the miR-214-3p/GPX4 axis.