Salivary gland homeostasis is maintained through acinar cell self-duplication

Dev Cell. 2015 Apr 20;33(2):231-7. doi: 10.1016/j.devcel.2015.02.013. Epub 2015 Apr 2.

Abstract

Current dogma suggests that salivary gland homeostasis is stem cell dependent. However, the extent of stem cell contribution to salivary gland maintenance has not been determined. We investigated acinar cell replacement during homeostasis, growth, and regeneration, using an inducible CreER(T2) expressed under the control of the Mist1 gene locus. Genetic labeling, followed by a chase period, showed that acinar cell replacement is not driven by the differentiation of unlabeled stem cells. Analysis using R26(Brainbow2.1) reporter revealed continued proliferation and clonal expansion of terminally differentiated acinar cells in all major salivary glands. Induced injury also demonstrated the regenerative potential of pre-labeled acinar cells. Our results support a revised model for salivary gland homeostasis based predominantly on self-duplication of acinar cells, rather than on differentiation of stem cells. The proliferative capacity of differentiated acinar cells may prove critical in the implementation of cell-based strategies to restore the salivary glands.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acinar Cells / cytology*
  • Acinar Cells / metabolism
  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / genetics*
  • Cell Differentiation / genetics
  • Cell Proliferation
  • Homeostasis / physiology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Salivary Glands / cytology*
  • Salivary Glands / physiology
  • Stem Cells / cytology

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Bhlha15 protein, mouse