Notch Signaling Drives Pro-Regenerative and Migratory Traits in Glandular Stem/Progenitor cells

Organoid models have advanced our understanding of adult stem/progenitor cell dynamics and function. However, uncovering the regulatory mechanisms of scarce and often quiescent stem cells in organs like the salivary glands remains challenging. Using single-cell RNA sequencing and bulk ATAC and RNA-sequencing analysis, we conducted in-depth profiling of the cellular populations and key signaling pathways characterizing a mouse submandibular salivary gland organoid (mSGO) model at different temporal stages and in response to radiation damage. We identified Sox9- and Itgb1- expressing cells as the most primitive adult stem/progenitor populations and uncover novel stemness and migratory roles for Cd44 -expressing cells. Moreover, we revealed that Notch signaling is essential for maintaining self-renewal and migration potential of these stem/progenitor cells post-irradiation. Extending these findings to patient-derived mSGOs, as well as murine and patient-derived mammary and thyroid gland organoids, we confirmed Notch signaling as a conserved regulator of stem/progenitor cell function under migrative and regenerative conditions.