Spatial transcriptomics reveals TGF-β-driven endothelial-mesenchymal transition in vascular remodeling of moyamoya disease.

Current understanding of molecular mechanisms driving moyamoya disease (MMD) remains limited. This study aimed to elucidate the role of TGF-β signaling in MMD vascular remodeling via endothelial-to-mesenchymal transition (EndMT). Spatial transcriptomics (10x Visium) was performed on 11 MMD specimens, while hematoxylin-eosin (HE) staining, immunohistochemistry (lHC), and immunofluorescence were conducted on a total of 51 MD and 11 control vascular specimens. Pseudotemporal trajectory analysis and cell-cell communication modeling were employed to map EndMT dynamics. MMD vessels exhibited intimal hyperplasia (STA: N1/N = 0.38 ± 0.12 vs 0.25 ± 0.12, p < 0.01) and medial atrophy. Spatial transcriptomics identified dual-positive SMC-Endo clusters (13.6%) within hyperplastic intima, co-expressing endothelial (PECAM1, CDH5) and mesenchymal markers (ACTA2, S100A4). The TGF-β pathway was significantly enriched in EndMT-active cells (FDR = 2.1 × 10-5), with elevated TGFBR1 and Snail expression in MMD intima (TGFBR1: 0.020 ± 0.008 vs 0.005 ± 0.004, p < 0.001; Snail: 0.10 ± 0.03 vs 0.06 ± 0.02, p < 0.01). Cell-cell networks revealed TGF-β-driven pro-fibrotic interactions. Immunofluorescence confirmed increased PECAM1+ α-SMA+ dual-positive cells in MMD vessels. These findings establish TGF-β/Snail-driven EndMT as a key mechanism in MMD vascular remodeling. Targeting TGF-β signaling or transitional cell states may halt or potentially reverse intimal hyperplasia, offering novel therapeutic strategies. Further validation in preclinical models is warranted.