Reporting in the January 2002 issue of the Journal of Cell Biology, Manuela Martins-Green, associate professor of biology, and three of her students note that the chicken chemokine "cCAF" is critical to healing chicken wounds, and appears similar in function to human chemokine interleuken-8 or IL-8.
The discovery may help researchers understand how wound-healing can be accelerated in humans.
Focusing the experimentation on chickens because chickens heal much the way humans do, Martins-Green's laboratory has shown that cCAF can by itself orchestrate much of the wound-healing process, including causing blood vessels to grow toward the wound to replace the blood system damaged by wounding and thereby provide nutrients for the recovering tissue.
Chemokines - small proteins that play important roles in wound healing and in response to cancerous tumors - first became known for their property of attracting white blood cells to sites of inflammation. (Inflammation is an important process in guarding against infection during wound healing and in fighting tumors.) "Our more recent work, still in progress, has shown that interleukin-8 and cCAF can behave in a similar way," Martins-Green says.
In December, 2001, Martins-Green and her students reported at the meeting of the American Society for Cell Biology in Washington, D.C. that IL-8 is also able to stimulate contraction and closure of wounds in chickens. "Both the human and chicken chemokines stimulate a common cell type -- fibroblasts -- to become a slightly different type of cell that has the ability to contract, much like a small muscle," Martins-Green says. "These cells proliferate in the healing tissue of the wound and then pull it together when the time is right."
The fact that cCAF and IL-8 produce the same effects in chickens strongly suggests that there is potential to develop treatments for humans who heal poorly, such as diabetics, people with pressure ulcers and people with bedsores. At present, Martins-Green's team is collaborating with chemists to modify the amino acids to obtain mimetics (compounds that mimic the function of other molecules via their high degree of structural similarity) that can still perform their function without being destroyed by enzymes in the wound.
"Chemokines are very small molecules that have few structural modifications," explains Martins-Green, "meaning that they can be synthesized easily and cheaply for drug development. Moreover, in many cases, including wound closure, the process can be accomplished by even smaller parts of the molecules, called peptides, suggesting that drugs could be made and included in drops, dressings, ointments, and so on. This would be of great benefit to society in that mimetics are not only stable and easy to apply but also cheap to manufacture."
Journal
Journal of Cell Biology