Sigma–1 receptor activation alleviates blood–brain barrier disruption post cerebral ischemia stroke by stimulating the GDNF–GFRα1–RET pathway

Blood–brain barrier (BBB) disruption is one of the most important pathological manifestations of ischemic stroke. Reducing BBB collapse is effective in alleviating brain parenchymal injury and cognitive dysfunction. Our previous study reported that Sigma–1 receptor (Sig–1R) activation in cerebral microvascular endothelial cells (CMECs) ameliorated BBB impairment, but the detailed mechanism remains unclear. In this study, we investigated Sig–1R activation as a BBB integrity promoter via many post ischemic stroke pathways. Sig–1R activation in BBB–associated astrocytes can increase glia–derived neurotrophic factor (GDNF) secretion in bilateral common carotid artery occlusion (BCCAO) mice. Upregulated GDNF activates its receptors in CMECs to promote BBB integrity, and activated Sig–1R in CMECs facilitates this process. In vitro experiments have found that Sig–1R activation in CMECs promotes the interaction between the GDNF α1 receptor and transduction rearrangement gene, increasing PI3K–AKT–junction protein signaling pathway expression. Sig–1R activation could be an effective therapeutic method for preventing BBB damage in ischemic stroke and other neurological conditions.