Exosome-Derived Proteomic Signatures Highlight Pathogenic Mechanisms in Moyamoya Disease

BackgroundThe etiology and molecular mechanisms of Moyamoya disease (MMD) remain unclear. Exosomes, as carriers of bioactive molecules, may reflect disease-specific alterations and serve as potential biomarkers. This study aimed to investigate disease mechanisms using proteomic profiling of serum-derived exosomes (SDEs) in MMD. Materials and MethodsPeripheral blood each from 15 MMD patients and 15 healthy-controls were used to isolate SDEs via ultracentrifugation. Proteins from pooled SDEs were extracted, digested, and analyzed by LC-MS/MS. Differentially expressed proteins were examined using MetaboAnalyst, DAVID, Enrichr, STRING, and Cytoscape. Key targets were validated at transcript and protein levels using RT-qPCR and ELISA in independent cohorts. ResultsA total of 2,554 proteins were identified, with 213 showing differential expression (118 upregulated, 95 downregulated; p [≤] 0.05). Functional and pathway analyses revealed enrichment in angiogenesis, cytoskeletal remodeling, and endothelial signaling. PRKG2 and MYC were upregulated, while RHOA was downregulated, highlighting their involvement in focal adhesion and PI3K-AKT pathways. Validation confirmed these findings. ConclusionDysregulated proteins were linked to RHOA-ROCK and PI3K-Akt signaling, suggesting their role in driving VSMC phenotypic switching, contributing to vascular occlusion. These findings indicate that altered exosomal-proteins may participate in maladaptive vascular remodeling, although the initial trigger for VSMC transition remains unknown.