A New Imaging Method for Ocular Lens Protein Modifications

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DESCRIPTION (provided by applicant): The ocular lens provides a unique environment for protein biochemistry necessitated by the need to maintain transparency over the lifetime of the organism. After organelle loss, little protein turnover occurs allowing post-translational modifications to accumulate over the lifetime of the organism. It is these modifications that have been linked to protein aggregation, insolubilization, and cataract-formation. Although a number of modifications have been cataloged, the spatial distribution of modified proteins in the human lens has been little-studied. It is precisely the spatial patterns of modification that can differentiate normal developmental or regulatory modifications from age-related and cataract-specific modifications. The objective of this proposal is to develop a new imaging technology for measuring lens protein distributions with high spatial resolution. MALDI tissue imaging has been applied to several tissues to map tumor-specific proteins, organ-specific protein distributions, and distributions in infected versus normal tissues. The promise of imaging lens proteins and their modifications is that new mechanisms of cataractogenesis will be revealed. Indeed, in preliminary studies, two previously unreported modifications have been imaged directly from lens tissue. The first aim of this developmental application is to determine optimum sample preparation and image acquisition requirements for imaging ocular lens proteins. The second aim is apply the conditions determined in aim 1 to image human lenses of varying age and cataract status. Ultimately, new spatially-resolved information on lens protein modification will be acquired that can be used to formulate hypotheses on cataract formation and lead to strategies to delay the onset of pacification. PUBLIC HEALTH RELEVANCE: The development of a new imaging technology is proposed for ocular lens tissue in which the spatial distributions of age- and cataract-specific protein modifications will be acquired. Knowledge of spatial patterns of lens protein modifications achieved by this new technology will lead to new mechanistic hypotheses and potential therapeutic targets for cataracts.