Antimicrobial Drugs Could Come From Eye Proteins
September 25, 2012

Eye Proteins Proved Effective In Fighting Pathogens

Connie K. Ho for — Your Universe Online

Researchers from the University of California, Berkeley recently discovered that fragments of keratin protein in the eye have the power to prevent pathogens and could possibly be used to develop new antimicrobial drugs.

In the study, the group of vision scientists tested synthetic versions of the keratin fragments against pathogens. They discovered that the synthetic fragments were able to eliminate the bacteria that could have otherwise caused cystic fibrosis lung infections, staph infections, strep throat, and diarrhea. The results of the study will be published in the upcoming October issue of the Journal of Clinical Investigation.

“What´s really exciting is that the keratins in our study are already in the body, so we know that they are not toxic, and that they are biocompatible,” remarked the study´s principal investigator Suzanne Fleiszig, a professor at UC Berkeley´s School of Optometry who studies infectious diseases and microbiology, in a prepared statement. “The problem with small, naturally occurring, antimicrobial molecules identified in previous research is that they were either toxic or easily inactivated by concentrations of salt that are normally found in our bodies.”

Based on the findings, the researchers believe that the keratin fragment could be produced and utilized as therapeutics for a low cost. The proteins included in the study were taken from cytokeratin 6A, a filament protein that links together to produce a mesh layer throughout the cytoplasm of epithelial cells. The scientists in Fleiszig´s lab worked to understand how the eye can be successful against infections and discovered the benefits of cytokeratin 6A. In particular, they found that the surface of the eye does not have bacteria residing on top of it and, through various label culture experiments, corneal tissue proved strong to enough to kill other pathogens.

“We used to think that cytokeratins were primarily structural proteins, but our study shows that these fragments of keratin also have microbe-fighting capabilities,” noted study lead author Connie Tam, an assistant research scientist in Fleiszig´s lab, in the statement. “Cytokeratin 6A can be found in the epithelial cells of the human cornea as well as in skin, hair and nails. These are all areas of the body that are constantly exposed to microbes, so it makes sense that they would be part of the body´s defense.”

The tests of fragments from cytokeratin 6A also showed that the molecules could rapidly eliminate bacteria that were in water and in a saline solution. The saline solution proved that the keratin fragments could even withstand human tears that contained salt. Other experiments completed by the team of investigators highlighted how cytokeratin 6A fragments could limit bacteria from targeting epithelial cells, while the proteins could allow the bacterial membranes to leak and eliminate the pathogens quickly.

“It is very difficult to infect the cornea of a healthy eye,” continued Fleiszig in the statement. “We´ve even used tissue paper to damage the eye´s surface cells and then plastered them with bacteria, and still had trouble getting bacteria to enter the cornea. So we proposed that maybe there were antimicrobial factors that are unique to the eye.”

Following the current study, the researchers hope to pursue further research to determine different keratin fragments in the body that acts as defense mechanism.

“Keratins may represent a novel class of antimicrobials with the potential to be designed to selectively kill specific pathogens,” concluded Tam in the statement.