Mutation of the circadian clock gene per2 alters vascular endothelial function

• Published in: Circulation (New York, N.Y.) N.Y.), 2007-04, Vol.115 (16), p.2188-2195
• Main Authors: VISWAMBHARAN, Hema, CARVAS, Joao M, ANTIC, Vladan, MARECIC, Ana, JUD, Corinne, ZAUGG, Christian E, MING, Xiu-Fen, MONTANI, Jean-Pierre, ALBRECHT, Urs, ZHIHONG YANG
• Format: Article
• Language: English
• Subjects: Acetylcholine - pharmacology; Adenosine Triphosphate - pharmacology; Animals; Antioxidants - pharmacology; Aorta, Thoracic - drug effects; Aorta, Thoracic - physiopathology; Atherosclerosis (general aspects, experimental research); Biological and medical sciences; Blood and lymphatic vessels; Blood Glucose - analysis; Blood Pressure; Blood vessels and receptors; Cardiology. Vascular system; Cardiovascular Diseases - etiology; Cardiovascular Diseases - physiopathology; Cell Cycle Proteins - genetics; Cell Cycle Proteins - physiology; Circadian Rhythm - genetics; Circadian Rhythm - radiation effects; Cyclooxygenase 1 - biosynthesis; Cyclooxygenase 1 - genetics; Cyclooxygenase 1 - physiology; Cyclooxygenase Inhibitors - pharmacology; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Endothelium, Vascular - physiopathology; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation; Indomethacin - pharmacology; Ionomycin - toxicity; Lipids - blood; Male; Medical sciences; Mice; Mice, Knockout; NG-Nitroarginine Methyl Ester - pharmacology; Nitric Oxide - deficiency; Nitric Oxide Donors - pharmacology; Nitric Oxide Synthase Type II - biosynthesis; Nitric Oxide Synthase Type II - genetics; Nitric Oxide Synthase Type III; Nitroprusside - pharmacology; Nuclear Proteins - genetics; Nuclear Proteins - physiology; Period Circadian Proteins; Receptor, Muscarinic M3 - biosynthesis; Receptor, Muscarinic M3 - genetics; Transcription Factors - genetics; Transcription Factors - physiology; Vasodilation - drug effects; Vasodilation - physiology; Vertebrates: cardiovascular system
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/CIRCULATIONAHA.106.653303

The circadian clock regulates biological processes including cardiovascular function and metabolism. In the present study, we investigated the role of the circadian clock gene Period2 (Per2) in endothelial function in a mouse model. Compared with the wild-type littermates, mice with Per2 mutation exhibited impaired endothelium-dependent relaxations to acetylcholine in aortic rings suspended in organ chambers. During transition from the inactive to active phase, this response was further increased in the wild-type mice but further decreased in the Per2 mutants. The endothelial dysfunction in the Per2 mutants was also observed with ionomycin, which was improved by the cyclooxygenase inhibitor indomethacin. No changes in the expression of endothelial acetylcholine-M3 receptor or endothelial nitric oxide synthase protein but increased cyclooxygenase-1 (not cyclooxygenase-2) protein levels were observed in the aortas of the Per2 mutants. Compared with Per2 mutants, a greater endothelium-dependent relaxation to ATP was observed in the wild-type mice, which was reduced by indomethacin. In quiescent aortic rings, ATP caused greater endothelium-dependent contractions in the Per2 mutants than in the wild-type mice, contractions that were abolished by indomethacin. The endothelial dysfunction in the Per2 mutant mice is not associated with hypertension or dyslipidemia. Mutation in the Per2 gene in mice is associated with aortic endothelial dysfunction involving decreased production of NO and vasodilatory prostaglandin(s) and increased release of cyclooxygenase-1-derived vasoconstrictor(s). The results suggest an important role of the Per2 gene in maintenance of normal cardiovascular functions.