Fig 1: Patterns of CD26 Expression in Intact Normal Skin and Skin Wound Models. (A) Immunohistochemical staining of CD26 in samples of excisional wounds on days 7, 14 and 21. The lower panel corresponds to the high magnification area in the upper panel. (B) Immunohistochemical staining of CD26 in burn wound samples on days 7, 14, and 21. The lower panel corresponds to the high magnification area in the upper panel. (C) The mRNA expression levels of CD26 and Col1 were significantly increased in samples of skin excisional wounds compared with normal skin (n=5). (D) The mRNA expression levels of CD26 and Col1 were significantly increased in burn wound samples compared with normal skin (n=5). (E) The proportion of CD26+ fibroblasts was significantly higher in WFs than in NFs (detected by FACS and its quantification) (n=5). Scale bar: 200 µm, t test, * P<0.05 vs Intact skin group, ** P<0.01 vs Intact skin group.
Fig 2: Sitagliptin inhibits the pathological features of CD26+ wound ?broblasts in vitro. (A) The expression of CD26 and Col1 in WFs and CD26+ WFs was measured by western blot following a concentration gradient of sitagliptin treatment. Representative images are shown. (B) Immunofluorescent staining of CD26 in WFs and CD26+ WFs after sitagliptin treatment. Representative images are shown. (C) The migration ability of CD26+ WFs was significantly reduced following sitagliptin treatment (20 nM) in wound healing assays. (D) The migration ability of CD26+ WFs was significantly reduced after sitagliptin treatment (20 nM) in transwell assays. (E, F) An evident increase in apoptosis within the WFs and CD26+ WFs following sitagliptin treatment (20 nM) as assayed by Annexin V-PI staining and its quantification (n=5). Scale bar: 100 µm. t test, * P<0.05 vs WF group, ** P<0.01 vs WF group.
Fig 3: Pharmacological inhibition of CD26 inhibits collagen biosynthesis during skin wound healing and reduces scar formation. (A) Immunohistochemistry staining of CD26 in samples of normal skin, burn wounds, and wounds treated with sitagliptin. Scale bar: 100 µm. (B) Masson staining in samples of normal skin, burn wounds, and wounds treated with sitagliptin and its quantification (n=5). Scale bar: 200 µm. (C) The protein expressions levels of CD26 and Col1 in tissue samples following sitagliptin treatment were measured by western blot. Representative images are shown. (D) The mRNA expression levels of CD26 and Col1 were significantly decreased in samples of skin burn wounds following sitagliptin treatment (n=5). t test, * P<0.05 vs Normal group, ** P<0.01 vs Normal group.
Fig 4: CD26 promotes cell proliferation, migration, and collagen biosynthesis in vitro. (A) Cell proliferation was remarkably increased in CD26+ WFs (CCK-8 viability assay). (B) The expressions levels of CD26 and Col1 were significantly increased in CD26+ WFs. Representative images of WB are shown. (C) The concentrations of CD26 and Col1 in the supernatant were determined by ELISA (n=5). * P<0.05 vs CD26+ NF group, ** P<0.01 vs CD26+ NF group. (D) Significant enhancement of cell migration in CD26+ WFs as gauged by wound healing assay and quantification (n=5). * P<0.05 vs CD26- NF group, ** P<0.01 vs CD26- WF group. (E) Significant enhancement of cell migration in CD26+ WFs as gauged by transwell assay and its quantification (n=5). ** P<0.01 vs CD26- NF/WF group. Scale bar: 100 µm, t test.
Supplier Page from Abcam for Mouse DPP4 ELISA Kit (CD26)