KGF, otherwise known as the Keratinocyte growth factor, is a protein, encoded by the FGF7 gene in humans. KGF has been linked to proliferation, DNA repair, and more.
The Function Of KGF
The protein encoded by this gene is in the fibroblast growth factor family. These ‘FGF’ family members possess a range of mitogenic and cell survival activities. You will find that they are involved in a variety of biological processes, these include:
● embryonic development
● cell growth
● tissue repair
● tumor growth and invasion.
This protein can be considered a potent epithelial cell-specific growth factor, whose mitogenic activity is predominantly exhibited in keratinocytes. However, it is not exhibited in fibroblasts and endothelial cells as you might think.
Keratinocyte growth factor (KGF) has an important part in developing thymocytes with its immunological activity. The secretion of this increases with the degree of development of thymocytes, and is found to be the strongest when it is at the single positive, or SP stage in CD4 lymphocytes and CD8 thymocytes. KGF stimulates the production of TSLP (and IL-6) in the thymic epithelium. That being said, KGF has zero effect on IL-7 production. KGF also reduces the expression of MHC class II molecules in thymic epithelium and inhibits the development of CD4 T thymocytes, however, it expands its compartment increases cellularity in bone marrow, which is caused via FGFRIIIb.
More About KGF And its Effect On The Body
● KGF is a heparin binding growth factor that exerts effects on epithelial cells in a paracrine way through interaction with KGF receptors.
● Preclinical data has demonstrated that KGF can prevent lung and gastrointestinal toxicity after chemotherapy and radiation.
● In the experimental allogeneic bone marrow transplant scenario KGF has shown ability to prevent graft-versus-host disease by maintaining gastrointestinal tract integrity and acting as something called a "cytokine shield". This helps to prevent subsequent proinflammatory cytokine generation.
● Within this setting, KGF has also shown an ability to prevent experimental idiopathic pneumonia syndrome by stimulating production of surfactant protein A, promoting alveolar epithelialization and attenuating immune-mediated injury.
● Perhaps most surprising, is the fact that KGF appears able to maintain thymic function during allogeneic stem cell transplantation and as such works to promote T cell engraftment and reconstitution.
● These beneficial effects are put down to the multiple mechanisms that all together act to strengthen the integrity of the epithelial barrier. This includes the stimulation of things like cell proliferation, migration, differentiation, survival, DNA repair, and induction of enzymes that are involved in the detoxification of reactive oxygen species.
The upregulation of the KGF protein after epithelial injury suggested it played a very important role in tissue repair within the body. Preclinical data from several animal models including mice demonstrated that recombinant human KGF could enhance the regenerative capacity of epithelial tissues and protect them from a wide variety of toxic exposures.
When looking at KFG’s success in ameliorating chemoradiotherapy-induced OM in humans and tissue damage in a variety of animal models, it becomes clear that additional clinical applications of KGF are important and make for a worthwhile investigation.