The Guardian of Human Skeleton: FGFs

Fibroblast growth factor (FGFs) is a polypeptide composed of about 150-200 amino acids and exists in two closely related forms, namely, basic fibroblast growth factor (bFGF) and acidic fibroblast growth factor (aFGF). Its receptor (FGFR) belongs to the receptor protein tyrosine kinase, currently known FGFR mainly includes four types, FGFR1, FGFR2, FGFR3 and FGFR4. Clinically, FGFR overexpression and activation in tumor tissues are found to be associated with the occurrence of a variety of cancers, which can promote tumor angiogenesis and tumor cell proliferation. Therefore, FGFR is widely considered as an important drug target for anti-tumor, which has attracted extensive attention from pharmaceutical scientists in various countries.

In vitro experiments, both types of FGF stimulated the DNA synthesis of osteoblast-like cells isolated from rat cranial cap. Meanwhile, bFGF stimulated the colony formation of differentiated chondrocytes in AGAR, playing a role in mitogen and morphology. AFGF can be formed by macrophages, cartilage and chondrocytes, which can stimulate the proliferation of immature chondrocytes and their progenitors. In vivo studies, FGF has been observed to promote the repair of articular cartilage. The expression of FGF was also found in the mouse fracture model by immunohistochemistry.

In addition, fibroblast growth factor has the following main effects on the human body:

  1. Effects on the skeletal system: It promotes the generation of a large number of osteoblasts and inhibits osteoclasts. To treat osteoporosis, femoral head necrosis, arthritis, rheumatism and diseases caused by calcium deficiency.
  2. Effects on the digestive system: It can strengthen gastrointestinal function, promote the digestion of enzymes, increase appetite, treatment of chronic gastritis.
  3. Effects on the blood system: It can strengthen the hematopoietic function of bone marrow, promote the generation of stem cells, and then generate a large number of red blood cells and white blood cells. Strengthening left ventricular thickness, enhancing myocardial elasticity, effectively treating heart disease. Effectively removing low density protein in the blood, preventing deposition in the blood vessel wall, and treating thrombosis.

Here are some important FGFs members and their main functions below:

  1. FGF2

Fibroblast growth factor 2(FGF2), also called the basic fibroblast growth factor(bFGF), is widely involved in cell growth, differentiation, migration, angiogenesis and tumorigenesis. The FGF2 gene is located at 4q26 of human chromosome, the length of which is 38kb, contains 3 exons and 2 introns. The active FGF2 can be combined with the fibroblast growth factor receptor (FGFR) which has the nature of tyrosine kinase receptor (FGFR) through heparin sulfate proteoglycans (HSPG), activate PKC, Ras /Raf /MEK/ERK, P13K, JAK/STAT and other signaling pathways, and participate in the regulation of cell proliferation, differentiation and malignant transformation. In the cardiovascular system, studies have shown that FGF2 is involved in cardiac hypertrophy caused by stress load and angiotensin. However, some studies also have shown that FGF2 can cause cell chromatin concentration, inhibit proliferation and cause cell apoptosis. Clearly, the cardiovascular role of FGF2 is not fully understood.

  1. FGF18

FGF18 is a highly conserved protein composed of 207 amino acids, with 30% to 70% homology with other members of FGFs found. FGF18 exists in a variety of cell types, and its function is not limited to skeletal development, but can stimulate the proliferation of numerous mesenchymal cells, epithelial cells and tissues, including lung, kidney, heart, testis, spleen, skeletal muscle and brain. As a member of the growth factor family, FGF18 plays an important role in morphogenesis, tumor growth and other cellular and tissue development. Compared with other growth factors except wound surface repair, FGF18 has potential clinical value in the treatment of skeletal diseases such as chondrodysplasia, chondroplasia and bone repair, with a wider range of effects. The decreased expression of FGFR3 was also observed by studying the FGFR3 and STAT1 signaling pathways, suggesting that FGF18 may play a role independent of FGFR3.

  1. FGF23

FGF23 is an endocrine protein synthesized by osteoblasts and osteoblasts. It has been confirmed that the main role of FGF23 is to regulate the level of blood phosphorus as a hormone, which plays an important role in the metabolism of calcium and phosphorus, parathyroid gland, as well as participates in the regulation of bone mineral metabolism. FGF23 is a protective factor for kidney, promoting urinary phosphorus excretion and maintaining stable blood phosphorus metabolism.

In addition, FGF also has powerful functions and deep repair effect. The study of FGFs plays an immeasurable role in modern clinical medicine, surgery and cosmetic surgery.