Neurotrophin signaling is a central mechanism of salivary dysfunction after irradiation that disrupts myoepithelial differentiation

The mechanisms that prevent regeneration of irradiated (IR) salivary glands remain elusive. Bulk RNAseq of IR versus non-IR human salivary glands showed that neurotrophin signaling is highly disrupted post-radiation. Moreover, neurotrophin receptors (NTRs) are significantly upregulated in myoepithelial cells (MECs) post-IR, and scRNAseq revealed that MECs are a main source of neurotrophin ligands. Using two ex vivo models, we show that nerve growth factor (NGF) is essential for MEC differentiation during development, whereas upregulation of NTRs in adult MECs is associated with differentiation defects. The latter morphological abnormalities were confirmed in MECs of human IR glands. As MECs are required for proper acinar cell contraction and secretion, we propose that MEC-specific upregulation of NTRs post-IR disrupts MEC differentiation and potentially hinders the ability of the gland to regenerate. Overall design: Alejandro M. Chibly