Analysis Of Fibrogenic Ability Of CD26 Positive Fibroblast Cell Population In Keloid Disease

ObjetiveWe aim to verify CD26 expression differences between keloid fibroblasts(KFs)and normal skin fibroblasts(NFs)as well as investigate the function of CD26 positive(CD26+)and CD26 negative(CD26-)fibroblasts in keloid progression.Subsequent tests analyzed the effect of CD26 inhibitor diprotin A on CD26+ keloid fibroblasts.This study paves the way to future studies with innovative strategies that focus on targeting KFs by novel cell lineages and potentially important clinical implications for the management of keloids.Methods1.Keloid fibroblasts were used as experimental group(n=10)and normal skin fibroblasts(NFs)were used as control group(n=10).Flow cytometry technology was used to analyze the expression of CD26 marker on NFs and KFs.2.KFs and NFs were obtained from the patients with keloid and normal skin tissues,and then were isolated by flow cytometery and later divided into four groups by their CD26 expression differences: KFs CD26+;KFs CD26-;NFs CD26+;NFs CD26-.The isolated fibroblasts were subsequently cultured for 7 days,and then cell proliferation was analyzed by CCK-8 assay and Ki-67 staining.Profibrotic phenotype differences were detected by q RT-PCR,western blot,ELISA and immunofluorescence.Scratching experiment and transwell assay were used to assess invasion ability of CD26+/CD26-fibroblasts.3.Diprotin A was used as a CD26 inhibitor to incubate the CD26+ KFs in vitro by gradient concentration to further investigate the function of CD26 fibroblasts in keloid.Results1.KFs displayed higher expression rate of CD26(46.65±13.97)% than NFs with that of(24.75±16.85)%,(P<0.01).2.Observation of cell morphology after 7-days in vitro culture diaplayed similar shape and cell density between CD26-cell population and CD26+ cell populationin.In both KFs and NFs groups,CD26+ fibroblasts showed accelerated proliferation compared with CD26-fibroblasts.3.CD26+ fibroblasts secreted excess keloid related cytokines(including TGF-β1,IGF-1 and IL-6)and extracellular matrix(including COL 1、COL 3 and FN)compared with CD26-fibroblasts in both NFs and KFs groups.4.CD26+ fibroblasts displayed more aggressive ability compared with CD26-fibroblasts in both NFs and KFs groups.5.CD26 Inhibitor suppressed the invasive growth and aberrant cytokines and ECM formation of CD26+ fibroblasts isolated from KFs ConclusionOur findings suggest that CD26+ fibroblasts showed higher proportion compare to CD26-fibroblasts in keloid dermis.Furthermore compared to CD26-fibroblasts,CD26+ fibroblasts play a prime role in keloid profibrotic progression.The present study paves the way for future study of pathological mechanism of keloid disease and provides the possibility to exploring new clinical implications for the management of keloids.