Exploring neuron-specific steroid synthesis and DHEAS therapy in Alzheimer's disease.

Alzheimer's Disease (AD) is a neurodegenerative disorder characterized by cognitive decline and memory loss. Recent studies have suggested a potential role for steroid synthesis in AD pathology. This study investigated the co-localization of steroidogenic enzymes in neuronal cells, changes in enzyme expression in an AD mouse model, and steroid expressions in human AD samples. Additionally, we conducted a steroidomic metabolomics analysis and evaluated the effects of dehydroepiandrosterone sulfate (DHEAS) treatment in an AD mouse model. Immunofluorescence analysis revealed significant co-localization of cytochrome P450 family 17 subfamily A member 1 (CYP17A1) and steroidogenic acute regulatory protein (StAR) proteins with α-synuclein in presynaptic neurons, suggesting active steroid synthesis in these cells. Conversely, such co-localization was absent in astrocytes. In the AD mouse model, a marked decrease in the expression of steroidogenic enzymes (Cyp11a1, Cyp17a1, Star) was observed, especially in areas with amyloid beta plaque accumulation. Human AD and MS brain tissues showed similar reductions in StAR and CYP17A1 expressions. Steroidomic analysis indicated a downregulation of key steroids in the serum of AD patients. DHEAS treatment in AD mice resulted in improved cognitive function and reduced Aβ accumulation. Our findings indicate a neuron-specific pathway for steroid synthesis, potentially playing a crucial role in AD pathology. The reduction in steroidogenic enzymes and key steroids in AD models and human samples suggests that impaired steroid synthesis is a feature of neurodegenerative diseases. The therapeutic potential of targeting steroid synthesis pathways, as indicated by the positive effects of DHEAS treatment, warrants further investigation.