Visualising age- and cataract-related changed within cell membranes of human eye lens using molecular rotors

ended

The lens of a mammalian eye is a unique tissue, which maintains high transparency during an individual lifespan, yet has no protein and lipid turnover. Thus, the eye lens is considered as one of ideal models of human aging. With age the proteins and lipids of the lens accumulate numerous post-translational modifications, leading to defects in the cell membrane structure and, therefore, to impairments of metabolite transport. The retarding of the metabolite exchange predisposes the lens nucleus to oxidative stress – a key factor in the formation of cataracts. Therefore, a study of the normal functioning of the lens, as well as age- and cataract-related changes in metabolite transport through the lens cells may shed light on the general mechanism of the lens aging and cataractogenesis. The present project is aimed at investigating and directly quantifying age- and cataract-related changes in the properties of cell membranes of the human eye lens by Fluorescence Lifetime Imaging Microscopy (FLIM), employing fluorescent viscosity-sensitive probes termed ‘molecular rotors’. We envisage that the results obtained will show the distribution of viscosity within membranes of fibre cells and will allow to directly visualise how the age and the early stages of cataract influence on fluidity of these lipid bilayers, which are of vital importance in maintaining the clarity of our eye lens and our vision. Analysis of age-related changes in the structure of membrane proteins and experiments with animal eye lenses subjected to photo-oxidation and chemical oxidation will provide additional information on the mechanisms of age- and cataract-related changes in viscosity within lens fibre cell membranes. Overall, this project addresses issues of fundamental importance in biophysics, as well as provides underpinning knowledge for understanding of health and disease and the treatment of an important eye condition: cataract.