Fluorescence-Guided Spatial Mapping of p21-Expressing Senescent Cells in Aged Liver at Single-Cell Resolution

) state than their resting counterparts. Transcriptomic profiling of p21-expressing cells indicated heterogeneous senescence-associated secretory phenotype (SASP) programs, with distinct inflammatory and remodeling signatures across cell identities and their spatial positions. In parallel, we identified an aggregation of interferon-stimulated gene (ISG)-expressing cells with limited overlap with p21 positivity, suggesting a distinct aging-associated stress program. Taken together, our fluorescence-guided spatial transcriptomic framework enables high-resolution, single-cell mapping of senescence in situ, delineating both senescent cell type specificity and cell identity-independent senescence programs, thereby advancing a more comprehensive understanding of regulatory mechanisms underlying aging.