Limited Regeneration of Adult Salivary Glands after Severe Injury Involves Cellular Plasticity

Abstract

Summary: In the adult salivary glands, the origin of replacement and regenerated acinar cells remains unclear. Although many reports describe the identification of stem cells in adult salivary glands, we have shown that differentiated acinar cells can be maintained and regenerated through self-duplication. Here, we have used genetic mouse models to further investigate acinar cell replacement and regeneration during homeostasis and after injury. Under normal conditions or after duct ligation, replacement of duct and acinar cells occurs through lineage-restricted progenitors. In contrast, after irradiation, in vivo lineage tracing shows that acinar, as well as duct, cells contribute to acinar cell regeneration, revealing that cellular plasticity is involved in salivary gland repair. Our results also indicate that even after radiation damage, several cell populations have regenerative potential for restoring salivary gland function. : Using in vivo lineage tracing, Weng et al. demonstrate that salivary gland acinar and duct lineages are maintained separately under homeostasis and after duct ligation, but after irradiation, both duct and acinar cells generate acini. This indicates that several cell populations have the potential to restore salivary gland function.