Pre-ischaemic empagliflozin treatment attenuates blood–brain barrier disruption via β-catenin mediated protection of cerebral endothelial cells

Abstract Aims Microvascular endothelial cells dysfunction can significantly worsen ischaemic stroke outcomes by disrupting tight junctions and increasing the acquisition of adhesion molecules, accelerating blood–brain barrier (BBB) disruption and pro-inflammatory response. The identification of drugs that improve endothelial cell function may be crucial for ischaemic stroke. It has been validated that empagliflozin (EMPA), a novel antidiabetic drug, protects endothelial cells regardless of the diabetic status of the patient. However, the impact of EMPA on stroke outcomes is unclear. We hypothesized that EMPA would exert a beneficial effect on ischaemic stroke outcome by protecting microvascular endothelial cells against tight junction disruption and the increase of adhesion molecules. Methods and results Young adult male mice were administered with EMPA or vehicle (dimethyl sulfoxide) daily for 7 days before being subjected to transient middle cerebral artery occlusion (tMCAO). Neurological deficits were evaluated for up to 28 days post-tMCAO. Infarct volume, BBB disruption, and inflammatory status were assessed 1 day after tMCAO.bEnd.3 cells and primary brain microvascular endothelial cells were treated with EMPA or vehicle under oxygen and glucose deprivation/reperfusion (OGD/R), and the lactate dehydrogenase release, transendothelial electrical resistance, leakage of fluorescein isothiocyanate-dextran, and tight junction and adhesion molecules proteins were examined. Mechanistic studies probing the effect of EMPA on endothelial cells were conducted by RNA-seq. EMPA treatment before ischaemia markedly improved infarct volume, BBB disruption, and inflammation 1-day post-tMCAO, and further enhanced neurobehavioral function up to 28 days. Pre-treatment of EMPA attenuated endothelial cell dysfunction under OGD/R conditions. In mechanistic terms, RNA-seq data from isolated cerebral microvessels revealed that the Wnt/β-catenin signalling pathway was preserved in the EMPA group, in contrast to the vehicle group. Pre-treatment with EMPA inhibited β-catenin ubiquitination and promoted β-catenin translocation from the cytoplasm to the nucleus to improve endothelial cell function. Importantly, the β-catenin inhibitor XAV-939 eliminated this protective function of EMPA. Conclusion EMPA administration before tMCAO attenuated ischaemia/reperfusion-induced BBB disruption and inflammation via β-catenin-mediated protection of cerebral microvascular endothelial cells. Therefore, EMPA shows potential for improving stroke outcomes as an adjunctive preventive strategy.