Donor-aware integration of public single-cell and spatial transcriptomes identifies a VIC remodeling program and FN1-NT5E spatial association in calcific aortic valve disease

Calcific aortic valve disease (CAVD) involves interacting endothelial, interstitial, immune and extracellular-matrix programs, but public single-cell studies contain many cells and few donors. A staged, donor-aware computational workflow was applied to five public human transcriptomic datasets. GSE220774 was used for single-cell discovery; GSE51472, GSE194180 and GSE235995 for fixed-signature replication; and GSE306288 for donor-level spatial assessment. Donors or patients, rather than cells or spots, were treated as biological replicates. VIC9 ranked highest for a prespecified fibrocalcific composite, although reliable coverage was limited to two donors. Its CTHRC1/FAP/IBSP/CDKN2A core program increased across disease-stage, osteogenic-culture and independent patient datasets. FN1-NT5E was the only prespecified candidate pair detected above the 0.5% spot floor in all six spatial donors. Immediate-neighbor associations were positive in 6/6 donors (median Spearman rho = 0.0717; exact one-sided sign-test P = 0.015625) and remained directionally stable in sensitivity analyses. These results define a reproducible VIC9-like remodeling program and an FN1-rich, NT5E-associated spatial context. They are hypothesis-generating and do not establish direct binding, causal signaling, an irreversible VIC transition or a histologically defined calcification front.