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Alzheimer's disease (AD) is a progressive disorder that affects the brain and leads to cognitive decline and memory loss, with postmenopausal women being unduly affected. Estrogen is believed to exert neuroprotective effects by influencing amyloid-beta accumulation, tau hyperphosphorylation, oxidative stress, synaptic function, neuroinflammation, and brain-derived neurotrophic factor (BDNF) signalling. This review examines the role of estrogen in AD pathogenesis among postmenopausal women. A systematic literature search was conducted using PubMed, Scopus, and Web of Science. Keywords included "estrogen", "Alzheimer's disease", "neuroprotection", "amyloid-beta," and "BDNF." Inclusion criteria were peer-reviewed studies from the past 10 years focusing on estrogen's effects on AD mechanisms, neurobiology, and therapeutic relevance. Articles were screened by title and abstract. Followed by a full-text review to ensure methodological rigour and relevance. Evidence indicates that estrogen reduces amyloid beta burden, inhibits tau phosphorylation, mitigates oxidative stress, preserves synaptic connectivity, and suppresses neuroinflammation. Estrogen also modulates ApoE-linked lipid metabolism and enhances BDNF signalling, supporting neuronal survival and cognitive resilience. Declining estrogen after menopause increases vulnerability to AD. Understanding estrogen's neuroprotective mechanisms may support targeted therapeutic strategies. Hormone replacement therapy (HRT) and selective estrogen receptor modulators (SERMs) show potential, but further research is needed to optimise timing, dosage, and patient selection in postmenopausal AD prevention and management. Show less

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. To elucidate the role of ERβ/GPR40 axis in AD pathogenesis and to investigate the therapeutic potential of Vin in ameliorating AD-related deficits. 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. 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. 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. Show less

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive dysfunction that is closely associated with cholinergic system damage. Estrogen deficiency is a well-established risk factor for AD in women. Osthole (OST), a phytoestrogen with mild, bidirectional regulatory properties, has been proposed as a potential estrogen replacement. This study aimed to investigate the mechanisms by which OST ameliorates cognitive impairment. Cognitive deficits were induced in female Sprague-Dawley rats by bilateral ovariectomy (OVX), and OST was subsequently administered by oral gavage. Behavioral tests revealed that OST significantly improved learning and memory and reduced anxiety-like and depression-like behaviors in OVX rats. H&E staining and Nissl staining demonstrated that OST reversed neuronal damage in the hippocampus and cortex. Western blotting, ELISA, and immunofluorescence staining indicated that OST treatment restored the estrogen-cholinergic-NGF axis: E Show less