The Retinal Circadian Clock and Photoreceptor Viability

• Type of Material: Article
• Authors: Kenkichi Baba, Morehouse School of Medicine; Christophe P. Ribelayga, University of Texas Houston; Paul Iuvone, Emory University; Gianluca Tosini, Emory University
• Language: English
• Date: 2018-01-01
• Publisher: Springer Verlag (Germany)
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2018, Springer International Publishing AG, part of Springer Nature.
• Final Published Version (URL): http://dx.doi.org/10.1007/978-3-319-75402-4_42
• Title of Journal or Parent Work: Advances in Experimental Medicine and Biology
• ISSN: 0065-2598
• Volume: 1074
• Start Page: 345
• End Page: 350
• Grant/Funding Information: Research in the author’s laboratories is supported by NIH grants GM116760 to KB, EY018640 to CR, R01EY004864 and P30EY006360 to PMI, EY022216, EY026291 to GT, and an unrestricted departmental grant from Research to Prevent Blindness (Emory Department of Ophthalmology).
• Keywords: Photoreceptors; Science & Technology; Medicine, Research & Experimental; Life Sciences & Biomedicine; Clock genes; Aging; Cell Biology; COMPONENT; Research & Experimental Medicine; Cell viability; Ophthalmology; Cone; Oscillation; MAMMALIAN RETINA; Retinal degeneration; Circadian rhythm; RHYTHM; Knockout mice
• Research Categories: Health Sciences, Pharmacology; Biology, Neuroscience; Biology, Cell

Abstract

Circadian rhythms are present in most living organisms, and these rhythms are not just a consequence of the day/night fluctuation, but rather they are generated by endogenous biological clocks with a periodicity of about 24 h. In mammals, the master pacemaker of circadian rhythms is localized in the suprachiasmatic nuclei (SCN) of the hypothalamus. The SCN controls circadian rhythms in peripheral organs. The retina also contains circadian clocks which regulate many aspects of retinal physiology, independently of the SCN. Emerging experimental evidence indicates that the retinal circadian clocks also affect ocular health, and a few studies have now demonstrated that disruption of retinal clocks may contribute to the development of retinal diseases. Our study indicates that in mice lacking the clock gene Bmal1, photoreceptor viability during aging is significantly reduced. Bmal1 knockout mice at 8–9 months of age have 20–30% less nuclei in the outer nuclear layer. No differences were observed in the other retinal layers. Our study suggests that the retinal circadian clock is an important modulator of photoreceptor health.