Fibroblast Growth Factor 18 (FGF18) is a protein found naturally within the body. It acts as a signaling molecule, influencing how cells grow, specialize, and develop within different tissues. Understanding its actions is important for comprehending its impact on health and disease.
What is FGF18 and Its Basic Function?
FGF18 is a member of the fibroblast growth factor family, a group of proteins that regulate numerous cellular activities. As a signaling molecule, FGF18 binds to specific receptors on cell surfaces, particularly Fibroblast Growth Factor Receptor 3c (FGFR3c). This interaction helps control cell proliferation, differentiation, and migration, fundamental processes for tissue development and maintenance.
The protein is expressed in various tissues, including the lung, kidney, liver, and intestines. During embryonic development, its presence is noted in several distinct regions, indicating its broad influence on early formation. FGF18 is a pleiotropic growth factor, meaning it has multiple effects. Its core function involves promoting cell growth and regulating tissue development. Its activity depends on the expression of its corresponding FGF receptors in different cell tissues.
Key Biological Roles
FGF18 plays a significant role in skeletal development, particularly in the formation of cartilage and bone. It stimulates chondrogenesis, the process by which cartilage is formed, and is involved in the generation of hyaline cartilage, found in articular joints. This function is relevant for the health and maintenance of joint structures.
Beyond skeletal tissues, FGF18 also participates in tissue repair and regeneration. It promotes the proliferation of cells in various organs, including the lung, liver, stomach, and colorectum. This protein is also involved in wound healing and the regeneration of joint tissues following injury. Its ability to stimulate cell growth and differentiation supports the body’s natural repair mechanisms.
FGF18 influences other developmental processes, such as lung organogenesis, where it promotes the branching morphogenesis of the lung. It stimulates hepatic and intestinal cell proliferation. Studies suggest a role for FGF18 in hair growth and cortical neuronal activity.
Involvement in Disease
Dysregulation of FGF18 activity can contribute to the development or progression of various health conditions. In osteoarthritis, a degenerative joint disease, FGF18 plays a complex role in cartilage health. While it promotes cartilage formation, an imbalance in its signaling can impact disease progression. Research indicates that FGF18 can cause thickening of cartilage in some models of osteoarthritis.
FGF18 has also been linked to certain types of cancer, where its influence varies depending on the specific cancer type and cellular context. It can act as an oncogene, promoting the development of malignant tumors. For instance, FGF18 has been shown to promote the migration, proliferation, invasion, apoptosis, and angiogenesis of hepatocellular carcinoma cells. It also plays a role in promoting the growth and tissue progression of lung cancer cells, often through specific signaling pathways.
Therapeutic Applications
Knowledge about FGF18’s biological functions is being investigated for potential medical treatments. Its role in cartilage formation makes it a target for therapeutic intervention in conditions like osteoarthritis. Recombinant versions of FGF18, such as sprifermin, are undergoing clinical trials as potential treatments for osteoarthritis, aiming to stimulate cartilage repair and regeneration.
FGF18 is also being explored in regenerative medicine approaches, particularly for its ability to promote chondrogenic and osteogenic differentiation of stem cells. In cell culture, FGF18 is used to support the maintenance and proliferation of various cell types, including chondrocytes and fibroblasts. It can also help maintain the undifferentiated state of stem cells and guide their differentiation into chondrocytes and osteoblasts, which are crucial for cartilage and bone formation. These applications highlight FGF18’s potential in developing new strategies for tissue repair and regeneration.