Evening exposure to blue light stimulates the expression of the clock gene PER2 in humans.
We developed a non-invasive method to measure and quantify human circadian PER2 gene expression in oral mucosa samples and show that this gene oscillates in a circadian (= about a day) fashion. We also have the first evidence that induction of human PER2 expression is stimulated by exposing subjects to 2 h of light in the evening. This increase in PER2 expression was statistically significant in comparison to a non-light control condition only after light at 460 nm (blue) but not after light exposure at 550 nm (green). Our results indicate that the non-image-forming visual system is involved in human circadian gene expression. The demonstration of a functional circadian machinery in human buccal samples and its response to light opens the door for investigation of human circadian rhythms at the gene level and their associated disorders.
Cajochen
Christian
C
Centre for Chronobiology, Psychiatric University Clinics, University of Basel, CH-4025 Basel, Switzerland. christian.cajochen@unibas.ch
Jud
Corinne
C
Münch
Mirjam
M
Kobialka
Szymon
S
Wirz-Justice
Anna
A
Albrecht
Urs
U
D000328:Adult; D003116:Color; D003624:Darkness; D004307:Dose-Response Relationship, Radiation; D005260:Female; D015870:Gene Expression / Q000528:radiation effects*; D006801:Humans; D008027:Light; D008297:Male; D008550:Melatonin / Q000378:metabolism; D009092:Mucous Membrane / Q000378:metabolism / Q000528:radiation effects; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D056950:Period Circadian Proteins; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D009687:Nuclear Proteins; C421902:PER2 protein, human; D056950:Period Circadian Proteins; D014157:Transcription Factors; D008550:Melatonin