title: Melatonin reprogrammes proteomic profile in light-exposed retina in vivo.
abstract: Melatonin, a small organic molecule synthesized by the pineal gland and the retina, has a variety of physiologic functions such as circadian clock pacemaker and antioxidant. Retinal melatonin is down-regulated by light and is barely detectable during the day. The absence of melatonin in the retina during prolonged light exposure may contribute to light-induced retinal degeneration. We sought to investigate the impact of melatonin in the light-exposed retina using proteomic approaches. We exposed mice to either light (250-300lux) for 12h followed by 12h of darkness or the same intensity of continuous light for 7 days. In half of the animals exposed to continuous light, melatonin was injected each night. Proteomic analysis of the retina from these three groups of animals showed that five proteins prominently up-regulated by constant light were down-regulated by melatonin treatment. These five proteins were identified as vimentin, serine/threonine-protein phosphatase 2A, Rab GDP dissociation inhibitor alpha, guanine nucleotide-binding protein G(o) alpha, and retinaldehyde-binding protein. These five proteins are known to be involved in several cellular processes that may contribute to light-induced retinal degeneration. Identification of melatonin target proteins in our study provides a basis for future studies on melatonin's potential in preventing or treating light-induced retinal degeneration.
authors.affiliation: Department of Ophthalmology, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Ruonan
authors.initials: R
authors.lastname: Zhang
authors.forename: William J M
authors.initials: WJ
authors.lastname: Hrushesky
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Wood
authors.forename: Sung Haeng
authors.initials: SH
authors.lastname: Lee
authors.forename: Richard C
authors.initials: RC
authors.lastname: Hunt
authors.forename: Wan Jin
authors.initials: WJ
authors.lastname: Jahng
mesh_terms: D000818:Animals; D003624:Darkness; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D008550:Melatonin / Q000494:pharmacology*; D051379:Mice; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000528:radiation effects; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics; D012160:Retina / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*; D013997:Time Factors; D014746:Vimentin / Q000378:metabolism
chemical_list: D020543:Proteome; D014746:Vimentin; D008550:Melatonin