Activation of the sigma-1 receptor attenuates blood–brain barrier disruption by inhibiting amyloid deposition in Alzheimer’s disease mice

The sigma-1 receptor is an important target for drug development in several neuropsychiatric diseases, including Alzheimer's disease (AD). Accumulating evidence has shown that the integrity and functional activity of the blood-brain barrier (BBB) in AD are impaired, which is closely related to the movement of amyloid beta (Aβ) across the BBB and the formation of Aβ plaques. In this study, we investigated the effects of sigma-1 receptor activation on BBB disruption and Aβ levels in AD mice. We found that PRE-084, a sigma-1 receptor agonist, attenuated learning and memory deficits in Aβ-injected mice, significantly increased levels of low-density lipoprotein receptor-related protein 1 (LRP-1), and lowered the Aβ level synergistically in the brain. Moreover, the upregulation of vascular endothelial growth factor (VEGF) levels through the sigma-1 receptor may be involved in the reduction of the BBB permeability by PRE-084. The identification of this previously unexplored role of the sigma-1 receptor in alleviating BBB disruption via upregulating the levels of VEGF and LRP-1 in AD suggests that reversing BBB dysfunction through sigma-1 receptor activation may be a promising treatment for AD.