title: Day-night dependence of gene expression and inflammatory responses in the remodeling murine heart post-myocardial infarction.
abstract: Diurnal or circadian rhythms are fundamentally important for healthy cardiovascular physiology and play a role in timing of onset and tolerance to myocardial infarction (MI) in patients. Whether time of day of MI triggers different molecular and cellular responses that can influence myocardial remodeling is not known. This study was designed to test whether time of day of MI triggers different gene expression, humoral, and innate inflammatory responses that contribute to cardiac repair after MI. Mice were infarcted by left anterior descending coronary artery ligation (MI model) within a 2-h time window either shortly after lights on or lights off, and the early remodeling responses at 8 h postinfarction were examined. We found that sleep-MI preferentially triggers early expression of genes associated with inflammatory responses, whereas wake-MI triggers more genes associated with metabolic pathways and transcription/translation, by microarray analyses. Homozygous clock mutant mice exhibit altered diurnal gene expression profiles, consistent with their cycling before onset of MI. In the first 8 h, crucial for innate immune responses to MI, there are also significant differences in sleep-MI and wake-MI serum cytokine responses and in neutrophil infiltration to infarcted myocardium. By 1-wk post-MI, there are differences in survivorship between the sleep and wake MI mice that could be explained by the different molecular and cellular responses. Our whole body physiology, tissues, and cells exhibit endogenous daily rhythms, and understanding their role in triggering effective responses after MI could lead to new strategies to benefit patients with cardiovascular disease.
authors.affiliation: Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: Michael
authors.initials: M
authors.lastname: Bennardo
authors.affiliation: Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: Faisal
authors.initials: F
authors.lastname: Alibhai
authors.affiliation: Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: Elena
authors.initials: E
authors.lastname: Tsimakouridze
authors.affiliation: Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: Nirmala
authors.initials: N
authors.lastname: Chinnappareddy
authors.affiliation: Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: Peter
authors.initials: P
authors.lastname: Podobed
authors.affiliation: Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: Cristine
authors.initials: C
authors.lastname: Reitz
authors.affiliation: Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and.
authors.forename: W Glen
authors.initials: WG
authors.lastname: Pyle
authors.affiliation: Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Simpson
authors.affiliation: Centre for Cardiovascular Investigations, Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada; and tmartino@uoguelph.ca.
authors.forename: Tami A
authors.initials: TA
authors.lastname: Martino
mesh_terms: D000818:Animals; D056926:CLOCK Proteins / Q000276:immunology*; D002940:Circadian Rhythm / Q000276:immunology*; D016207:Cytokines / Q000276:immunology*; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D007113:Immunity, Innate / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009203:Myocardial Infarction / Q000276:immunology* / Q000473:pathology; D009205:Myocarditis / Q000276:immunology* / Q000473:pathology; D012890:Sleep / Q000276:immunology*; D015996:Survival Rate; D014851:Wakefulness
chemical_list: D016207:Cytokines; D056926:CLOCK Proteins
keywords: circadian; diurnal; heart; immune; myocardial infarction