Analysis of the expression of FAP-alpha protein in 2D-keloid fibroblast cultures and in 3D models of keloid

Objective: Keloids arise most often as a result of abnormal wound healing. The lesion characterizes inflammation and fibroproliferation. Fibroblast activation protein alpha (FAP-alpha) is one of enzymes engaged in keloid formation. It is serine protease that facilitates cells invasion and growth. FAP-alpha possess also non-enzymatic activity and plays role in activation of cell signaling. The aim of the study was to assess the impact of culture conditions on the proliferation of keloid fibroblasts and the expression of FAP-alpha. Analysis of utility of 3D models of keloid in in vitro study of pathogenesis of keloids was also made. Methods: NHDF and KEL FIB cells were cultured in vitro in 2D cultures and 3D Matrigel models. The viability of cells was assayed spectrophotometrically with WST-1 test. FAP-alpha protein amount in cell cultures and 3D models was evaluated with the use of ELISA test. Results: KEL FIB fibroblasts exhibited higher viability than NHDF fibroblasts in all three models of keloid. The expression of FAP-alpha is different in normal and keloid fibroblasts. In vitro conditions influence the expression of FAP-alpha in NHDF cells but not in KEL FIB cells. Conclusions: This preliminary study has shown that the expression of FAP-alpha, similarly to other enzymes engaged in keloid formation, is different in keloids in vivo and in in vitro models. FAP-alpha expression is modulated by in vitro conditions in normal fibroblasts but not in keloid fibroblasts.