1. Irx1 mechanisms for oral epithelial basal stem cell plasticity during reepithelialization after injury.
- Author
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Su D, Krongbaramee T, Swearson S, Sweat Y, Sweat M, Shao F, Eliason S, and Amendt BA
- Subjects
- Animals, Mice, Re-Epithelialization genetics, Cell Plasticity genetics, Cell Differentiation, Cell Movement, Gingiva cytology, Gingiva metabolism, Gingiva pathology, SOX9 Transcription Factor metabolism, SOX9 Transcription Factor genetics, Keratin-14 metabolism, Keratin-14 genetics, Stem Cell Niche, Epithelial Cells metabolism, Homeodomain Proteins genetics, Homeodomain Proteins metabolism, Keratinocytes metabolism, Transcription Factors genetics, Transcription Factors metabolism, Mouth Mucosa metabolism, Mouth Mucosa cytology, Mouth Mucosa pathology, Wound Healing physiology, Wound Healing genetics, Cell Proliferation, Stem Cells metabolism
- Abstract
The oral mucosa undergoes daily insults, and stem cells in the epithelial basal cell layer regenerate gingiva tissue to maintain oral health. The Iroquois Homeobox 1 (IRX1) protein is expressed in the stem cell niches in human/mouse oral epithelium and mesenchyme under homeostasis. We found that Irx1+/- heterozygous (Het) mice have delayed wound closure, delayed morphological changes of regenerated epithelium, and defective keratinocyte proliferation and differentiation during wound healing. RNA-Seq analyses between WT and Irx1+/- mice at 3 days postinjury (dpi) found impaired epithelial migration and decreased keratinocyte-related genes upon injury. IRX1-expressing cells are found in the gingival epithelial basal cell layer, a stem cell niche for gingival maintenance. IRX1-expressing cells are also found in cell niches in the underlying stroma. IRX1 activates SOX9 in the transient amplifying layer to increase cell proliferation, and EGF signaling is activated to induce cell migration. Krt14CreERT lineage tracing experiments reveal defects in the stratification of the Irx1+/- HET mouse oral epithelium. IRX1 is primed at the base of the gingiva in the basal cell layer of the oral epithelium, facilitating rapid and scarless wound healing through activating SOX9 and the EGF signaling pathway.
- Published
- 2025
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