Lens transparency is dependent upon the orderly arrangement of cell lamellae and the composition, distribution, and organization of its highly concentrated constituent proteins, the crystallins. Previous results indicate that maintenance of transparency in the metabolically active cortex is dependent upon a number of factors which differ substantially from those of the nuclear region. However, the role of metabolism in the maintenance of lens clarity remains vague. The objective of this proposal is to establish, and thus define, the linkage between the organizational stability of lens macromolecular components necessary for lens transparency, and energy yielding metabolic processes. Three areas of research will pursued in parallel: (I) Ex vivo lens incubation studies during which lenses will be subjected to established diabetic stress factors. The application of both invasive and non-invasive nuclear magnetic resonance (NMR) techniques will be coordinated to measure changes in lenticular metabolism, composition, and macromolecular organization. (II) Molecular studies to investigate our hypothesis that the macromolecular oraganization of the cortex is dependent upon a functional link between actin, gamma-crystallin, and L-alpha- glycerolphosphate (e.g., gamma-crystallin, and L-gamm- glycerolphosphate (e.g., gamma-crystallin effects on actin polymerization and the apparent L-alpha-glycerolphosphate binding to gamma-crystallin). (III) Developmental lens studies will continue to further define lens organizational changes occurring during the pre- and post-critical maturation periods and their impact on susceptibility to insult. The proposed studies will provide new insights into the sequence of molecular events which provoke the loss of lens transparency. Ultimately, such information may be of use in the design of non-invasive probes for the in vivo assessment of lens functional integrity.
