Vincamine as a GPR40 agonist shows potential in treating female Alzheimer’s disease

BACKGROUND: Women face a heightened risk of Alzheimer's disease (AD), partly attributed to post-menopausal estrogen loss. Given that ERβ activation avoids the oncogenic risks of ERα and GPR40 plays a pivotal role in neuronal function, the ERβ/GPR40 axis show a promising therapeutic target for anti-AD drug discovery. To inspect the role of this axis, we employed Vincamine (Vin), a monoterpenoid indole alkaloid from Madagascar periwinkle that we previously identified as a GPR40 agonist. PURPOSE: To elucidate the role of ERβ/GPR40 axis in AD pathogenesis and to investigate the therapeutic potential of Vin in ameliorating AD-related deficits. METHODS: We combined analyses of clinical data from female AD patients (GSE33000) with the research in 3×Tg-AD mice to examine the differences in ERβ/GPR40 expression. The binding of ERβ and GPR40 was detected by CUT&Tag assay, protein-DNA docking simulation and molecular dynamics simulation assays. Vin was used to evaluate the therapeutic potential of ERβ/GPR40 axis activation for AD. The underlying mechanisms were investigated by assay against the adeno-associated virus (AAV)-CMV-PHP.eB-KD-GPR40 injected 3×Tg-AD female mice. RESULTS: ERβ and GPR40 are both downregulated in brains of female AD patients and 3×Tg-AD mice, and ERβ directly binds to GPR40 promoter. Brain-specific GPR40 knockdown caused cognitive impairment in female wild type (WT) mice. Vin as a GPR40 agonist but not an ERβ ligand ameliorated AD-like pathology in 3×Tg-AD female mice. Specifically, Vin suppressed neuroinflammation via GPR40/NF-κB/NLRP3 pathway, inhibited neuronal tau hyperphosphorylation via GPR40/GSK3β/CaMKII pathway, while promoted synaptic plasticity via GPR40/PKA/CREB/BDNF pathway. CONCLUSION: To our knowledge, our study provides the first identification of the specific ERβ-binding regions and key residues within the GPR40 promoter, offering novel mechanistic insight into their transcriptional regulation. Furthermore, our work establishes ERβ/GPR40 axis as a potentially therapeutic strategy for female AD and highlight the medication interest of Vin in treating this disease.