IADR Abstract Archives
DDR1 Localizes to Epithelial Leading Edge During Palatal Wound Healing
Objectives: Discoidin domain receptor 1 (DDR1) is a non-integrin collagen receptor that affects resident and immune cell function and matrix remodeling. We investigated developmental expression of Ddr1 mRNA in mouse tissues and localization of DDR1 mRNA in human palatal biopsy healing, and determined whether phenytoin, a drug associated with gingival overgrowth, affected DDR1 expression in human healing.
Methods: In situ hybridization (ISH) was used to localize Ddr1 in mouse tissues. Circular 4-mm palatal wounds were created bilaterally in 20 human subjects (baseline). Phenytoin was applied on one side (test). Wound areas were harvested after 1 or 5 days. DDR1 ISH was performed on sections from 5 individuals on day 1 (n=2) or 5 (n=3) and compared to Masson’s trichrome-stained sections. Measurements of initial wound length and superficial epithelial migration were used to calculate Superficial Contraction Index (SCI) and DDR1 staining was quantified. Comparisons were analyzed by Student t-test.
Results: In mouse tissues at 8, 14, and 26 days postnatal, Ddr1 was expressed in epithelial cells in epidermis, hair follicles, enamel organ, and oral epithelium basal layers. In human tissues, DDR1 was similarly expressed in oral epithelium basal layers. In healing sections (days 1/5), DDR1 localized to the leading edge of ingrowing epithelium, as shown by comparable SCI measurements on DDR1 ISH and Masson-stained sections (0.2905 vs. 0.2945, p=0.84). DDR1 staining quantification showed comparable expression between 0-1 day (p=0.99, control; p = 0.39, test), 0-5 days (p=1, control; p = 0.62, test), and 1-5 days (p=0.8, control; p=0.14, test). DDR1 expression was not altered by phenytoin application.
Conclusions: In both mouse and human tissues, Ddr1/DDR1 is expressed in oral epithelium basal cells. DDR1 localizes to the ingrowing epithelium during human palatal wound healing, suggesting an important role in reestablishment of the epithelial layer. Application of phenytoin does not affect DDR1 during palatal wound healing.
Methods: In situ hybridization (ISH) was used to localize Ddr1 in mouse tissues. Circular 4-mm palatal wounds were created bilaterally in 20 human subjects (baseline). Phenytoin was applied on one side (test). Wound areas were harvested after 1 or 5 days. DDR1 ISH was performed on sections from 5 individuals on day 1 (n=2) or 5 (n=3) and compared to Masson’s trichrome-stained sections. Measurements of initial wound length and superficial epithelial migration were used to calculate Superficial Contraction Index (SCI) and DDR1 staining was quantified. Comparisons were analyzed by Student t-test.
Results: In mouse tissues at 8, 14, and 26 days postnatal, Ddr1 was expressed in epithelial cells in epidermis, hair follicles, enamel organ, and oral epithelium basal layers. In human tissues, DDR1 was similarly expressed in oral epithelium basal layers. In healing sections (days 1/5), DDR1 localized to the leading edge of ingrowing epithelium, as shown by comparable SCI measurements on DDR1 ISH and Masson-stained sections (0.2905 vs. 0.2945, p=0.84). DDR1 staining quantification showed comparable expression between 0-1 day (p=0.99, control; p = 0.39, test), 0-5 days (p=1, control; p = 0.62, test), and 1-5 days (p=0.8, control; p=0.14, test). DDR1 expression was not altered by phenytoin application.
Conclusions: In both mouse and human tissues, Ddr1/DDR1 is expressed in oral epithelium basal cells. DDR1 localizes to the ingrowing epithelium during human palatal wound healing, suggesting an important role in reestablishment of the epithelial layer. Application of phenytoin does not affect DDR1 during palatal wound healing.
