GALVESTON, Texas - University of Texas Medical Branch at Galveston researcher Irina A. Pikuleva has received a four-year, $1.2 million grant from the National Eye Institute to advance her research on the significance of particular enzymes in retinal function.

"This research will be critical for understanding the development of certain eye diseases that reduce vision," said Pikuleva.

Cytochrome P450 (P450 or CYP) enzymes metabolize a wide variety of substrates and play key roles in many biological processes. Only recently has it become clear that normal and pathological visual functions are among these.

A growing body of evidence suggests the importance of cholesterol in the retina for normal vision. However, little is known about cholesterol turnover in the retina and the significance of cholesterol-hydroxylating P450s in retinal function.

Two cholesterol-metabolizing P450s (27A1 and 46A1) were recently found to be highly expressed in the retina. CYP46A1 is a recently cloned, and therefore much less studied, enzyme. It is known, however, to control cholesterol elimination from the brain, and its deficiency may contribute to Alzheimer's disease.

The grant is focused on delineation of the specific roles of cholesterol-metabolizing P450s as well as of cholesterol metabolism in the retina.