Stromal TNF–NFκB signaling impairs acinar differentiation through inflammation-driven epithelial–stromal crosstalk in chimeric salivary gland organoids

Salivary gland organoids enable long-term epithelial expansion but lack stromal compartments that regulate glandular differentiation in vivo. Here, we developed chimeric salivary gland organoids (cSGOs) by layering embryonic day 13 stromal cells over postnatal day 1 epithelial organoids. cSGOs incorporated fibroblasts, immune cells, endothelial cells, and neuronal populations while preserving acino-ductal architecture. Single-cell RNA sequencing revealed that stromal fibroblasts supply FGF ligands supporting epithelial proliferation, yet acinar differentiation remained stalled. Pseudotime and pathway analyses identified TNF-NFκB signaling from stromal immune cells as selectively enriched in proacinar cells. Dexamethasone suppressed this inflammatory axis, expanded the proacinar population, and restored acinar marker expression. Direct NFκB inhibition with BAY11-7082 phenocopied the glucocorticoid effect, implicating epithelial NFκB as a stromal-derived inflammatory checkpoint limiting acinar maturation. These findings support a mechanistic link between stromal inflammation and impaired acinar differentiation and identify a candidate signaling node for therapeutic intervention.