Mucins: integral components of the ocular surface system

Ilene Gipson, PhD, received the Friedenwald Award for her seminal contributions to basic and clinicalunderstanding of wound healing, epithelial anchorage, and mucin biology in the areas of ocular surfaceand cornea research.

Dr. Gipson, senior scientist and ocular surface scholar, Schepens Eye Research Institute, andprofessor of ophthalmology, Department of Ophthalmology, Harvard Medical School, Boston, deliveredthe lecture entitled "The ocular surface: the challenge to enable and protect vision."

Her career in biology ultimately led to her interest in mucins, which are components of the tear filmthat protect the refractive surface. One of the most important findings that took place under herwatch was the isolation of H185, which was later determined to be a mucin, and which changed thedirection of the research taking place in her laboratory. Another important finding was that H185monoclonal antibody binding has altered distribution in dry eye. This was later followed by othermajor discoveries, i.e., mucin genes are expressed by the ocular surface epithelium, Sjörgen'ssyndrome is characterized by decreased expression of MUC5, ocular cicatrical pemphigoid has alteredexpression of glycoltransferases that add glycans to mucins, and vitamin A deficiency ischaracterized by lost expression of all mucins except MUC1.

The discovery that H185 and MUC16 are identical led to a number of considerations, such as: Is theredecreased expression, altered glycosylation, and increased shedding of mucin?

"Very little is known about mucins, which are the subject of recent effort. Perseverance resulted inidentifying H185 as MUC16 and as result we learned a great deal about the protective mucins of theocular surface and their alterations in surface disease," Dr. Gipson said.

The future of this field lies in research into the ocular surface, Dr. Gipson emphasized.

"There are tremendous opportunities there because we know so little about the ocular surface systemand about the composition of the apical membranes on the surface of the eye," Dr. Gipson said. "We doknow that if there is an imbalance in the finely tuned integrated system on the ocular surface,disease processes can occur. There are no adequate treatments for dry eye syndrome and ocular surfacedisease.

"The ocular surface is an extraordinary model for the study of basic mechanisms of epithelialfunction and defense," Dr. Gipson concluded. "The surface of the eye is a remarkable place to look ateverything in biology, particularly as it relates to mucin function. I am confident that through allour basic research new treatments for devastating ocular surface diseases will be developed."