FGF21 promotes wound healing of rat brain microvascular endothelial cells through facilitating TNF-α-mediated VEGFA and ERK1/2 signaling pathway.

[BACKGROUND] Wound healing is an essential physiological process in recovery after microsurgery.

[OBJECTIVES] To further understand the functions of fibroblast growth factor 21 (FGF21), the roles of this factor were examined and its correlations with inflammation, vascular endothelial growth factor A (VEGFA) and ERK1/2 signaling pathway activation were analyzed.

[MATERIAL AND METHODS] Rat brain microvascular endothelial cells (RBMECs) were treated with interleukin (IL)-1β and used for the experiments. Cell Counting Kit-8 (CCK-8) was used to detect the cell viability of RBMECs after treatment with IL-1β (1 ng/mL) and FGF21 or VEGFA overexpression, while changes in apoptosis were measured through flow cytometry. Migration was checked through the scratch test. FGF21 and VEGFA RNA expression was assessed using reverse-transcription quantitative polymerase chain reaction (RT-qPCR), which was also used to examine RNA expression of Bcl-2, Bax and caspase-3. After IL-1β treatment and FGF21 overexpression, tumor necrosis factor alpha (TNF-α) and tumor growth factor β1 (TGF-β1) proteins level were observed with enzyme-linked immunosorbent assay (ELISA), which was also applied to check the expression of ERK1/2 after overexpression of FGF21 and VEGFA. PD98059 (50 μM), an ERK1/2 inhibitor, was used to examine the roles of ERK1/2 in regulating cell viability and apoptosis.

[RESULTS] The IL-1β treatment significantly decreased the viability of RBMECs and TGF-β1, but promoted cell apoptosis and TNF-α expression. FGF21 was downregulated by IL-1β treatment but its overexpression enhanced the viability of RBMECs and TGF-β1 and ERK1/2 protein levels, and attenuated cell apoptosis and TNF-α. Upregulated TNF-α restrained cell viability and apoptosis of RBMECs after FGF21 overexpression, and its upregulation not only suppressed FGF21, but also VEGFA. Moreover, VEGFA suppression by TNF-α increased cell viability and ERK1/2 protein levels, and suppressed the apoptosis of RBMECs through its upregulation. However, PD98059 obstructed the functions of FGF21 and VEGFA.

[CONCLUSIONS] FGF21 promoted the cell viability of RBMECs through upregulating TNF-α-mediated VEGFA and ERK1/2 signaling.