Original Article
Subject Categories: Keratinocytes/Epidermis
Journal of Investigative Dermatology (2002) 119, 1220–1223; doi:10.1046/j.1523-1747.2002.19619.x
Low-dose Ultraviolet B Rays Alter the mRNA Expression of the Circadian Clock Genes in Cultured Human Keratinocytes
Shigeru Kawara, Régine Mydlarski, Adam J Mamelak*, Irwin Freed*, Binghe Wang*, Hideaki Watanabe*, Gulnar Shivji, Sherine K Tavadia, Hirotake Suzuki, George A Bjarnason†, Richard C K Jordan† and Daniel N Sauder*
- Division of Dermatology, Sunnybrook & Women's College Health Sciences Center, University of Toronto, Ontario, Canada
- *Department of Dermatology, Johns Hopkins University, Baltimore, MD, U.S.A.
- †Department of Medicine, Toronto-Sunnybrook Regional Cancer Center, University of Toronto, Ontario, Canada
Correspondence: Dr Daniel N. Sauder, Department of Dermatology, Johns Hopkins Outpatient Center, Johns Hopkins University, 601 N. Caroline Street, Room 6068, Baltimore, MD 21287-0900, U.S.A. Email: dsauder@jhmi.edu
Received 11 December 2000; Revised 7 February 2002; Accepted 24 August 2002.
Abstract
Current understanding of mammalian circadian rhythms suggests that they are regulated by light targeting signaling pathways in the hypothalamic suprachiasmatic nuclei. Recently, investigators have identified the existence of extraretinal photoreceptors and a potential role for the skin in this regulatory process has been implied. We demonstrated that mRNA of the circadian clock genes Per1, Clock, and bmal1/mop3 are expressed in normal human cultured keratinocytes. Low-dose ultraviolet B rays initially downregulate all circadian clock genes and then induce altered expression of the genes in keratinocyte cell cultures. Ultraviolet light targeting superficial layers of skin (keratinocytes) may therefore contribute to circadian rhythm modulation.
Keywords:
bmal1, mops, circadian rhythm, Clock, Per
