FGF-2/bFGF

FGF-2/bFGF is a member of the fibroblast family and has a high affinity for heparin. FGF-2 plays an important role in tendon to bone healing, cartilage repair, bone repair, and nerve regeneration. FGF-2 specifically binds to tyrosine kinase receptors and activates the FGF/FGFR signaling pathway. Subsequently, FGF-2 influences cell proliferation, differentiation and apoptosis, as well as immune regulation by transducing other classical pathways. For example, FGF-2 regulates the JAK-STAT signaling pathway to regulate cartilage metabolism. FGF-2 also acts as a mitotic promoter to accelerate cell proliferation. Therefore, (1) FGF-2 is an important growth factor in the healing process of ligament/tendon injury. In vitro experiments, low-dose FGF-2 can stimulate the proliferation and differentiation of bone marrow mesenchymal stem cells, and up-regulate the mRNA expression of type I/III collagen and fibronectin. However, high doses of FGF-2 did not stimulate extracellular matrix (ECM) protein proliferation and gene expression. (2) FGF-2 is also an endogenous and intrinsic growth factor in cartilage repair. FGF-2 binds to heparan sulfate proteoglycan and is stored in the ECM of articular cartilage. When cartilage is damaged or degenerated, ECM rapidly releases FGF-2 and activates ERK signaling pathways to promote cartilage regeneration. FGF-2 exhibits a biphasic effect in combination with its specific receptor. FGF-2 combined with FGFR3 promoted the repair of articular cartilage. FGF-2 combined with FGFR1 promoted the degeneration of articular cartilage^[1]. FGF-2 is expressed in granulosa cells and colliculus cells, as well as hepatocellular cancer cells, but not in non-cancerous liver tissues. This reveals the role of FGF-2 in brain tumors, particularly glioblastoma. According to studies, FGF-2 is a known carcinogenic factor in GBM. FGF-2 increases the self-renewal of glioblastoma stem cells and contributes to the growth and vascularization of glioma^[2]. FGF-2 protein is highly conserved in some species, and the similarity rate of human FGF-2 protein sequence to rat, mouse, and bovine was 97.4%, 95.45%, and 98.71%, respectively.