The Circadian PER2 Enhancer Nobiletin Reverses the Deleterious Effects of Midazolam in Myocardial Ischemia and Reperfusion Injury

Abstract

Background: Recently, we identified the circadian rhythm protein Period 2 (PER2) in robust cardioprotection from myocardial ischemia (MI). Based on findings that perioperative MI is the most common major cardiovascular complication and that anesthetics can alter the expression of PER2, we hypothesized that an anesthesia mediated downregulation of PER2 could be detrimental if myocardial ischemia and reperfusion (IR) would occur. Methods and Results: We exposed mice to pentobarbital, fentanyl, ketamine, propofol, midazolam or isoflurane and determined cardiac Per2 mRNA levels. Unexpectedly, only midazolam treatment resulted in an immediate and significant downregulation of Per2 transcript levels. Subsequent studies in mice pretreated with midazolam using an in-situ mouse model for myocardial (IR)-injury revealed a significant and dramatic increase in infarct sizes or Troponin-I serum levels in the midazolam treated group when compared to controls. Using the recently identified flavonoid, nobiletin, as a PER2 enhancer completely abolished the deleterious effects of midazolam during myocardial IR-injury. Moreover, nobiletin treatment alone significantly reduced infarct sizes or Troponin I levels in wildtype but not in Per2−/− mice. Pharmacological studies on nobiletin like flavonoids revealed that only nobiletin and tangeritin, both found to enhance PER2, were cardioprotective in our murine model for myocardial IR-injury. Conclusion: We identified midazolam mediated downregulation of cardiac PER2 as an underlying mechanism for a deleterious effect of midazolam pretreatment in myocardial IR-injury. These findings highlight PER2 as a cardioprotective mechanism and suggest the PER2 enhancers nobiletin or tangeritin as preventative therapy for myocardial IR-injury in the perioperative setting where midazolam pretreatment occurs frequently.

Circadian-Hypoxia Link and its Potential for Treatment of Cardiovascular Disease

“…Indeed, our group found that nobiletin induces cardiac Per2 and provides a cardioprotective effect from myocardial IR injury in a Per2-dependent manner. Furthermore, we demonstrated that the deleterious effects on the heart of the commonly-prescribed benzodiazepine midazolam can be rescued when nobiletin is administered prior to myocardial IR-injury [208]. Our studies are in line with other groups targeting nuclear receptors, in particular REV-ERBs, as a promising strategy in the context of cardiac IR-injury.…”

Intense Light-Mediated Circadian Cardioprotection via Transcriptional Reprogramming of the Endothelium

“…Moreover, our in vivo and in vitro studies suggest that light-elicited transcriptional reprogramming of endothelial cells protects endothelial barrier function during IR injury. Together with previous studies on myocardial IR injury (Yang et al, 2016), these studies highlight the importance of cardiac endothelia in IR injury and point toward unrecognized therapeutic strategies for cardiovascular disease using intense light or pharmacological compounds, such as the circadian rhythm enhancer nobiletin (Gile et al, 2018; Oyama et al, 2018), to increase the amplitude of endothelial PER2. Despite this strong evidence, our studies are limited to analysis of endothelia-specific PER2-deficient mice; thus, the contribution of other cardiac cells cannot be fully excluded (Seo et al, 2015).…”

Endothelial specific PER2 at the crossroads of light elicited circadian amplitude enhancement as novel cardioprotective strategy and transcriptional regulation of HIF1A-dependent metabolic adaptation to myocardial ischemia

“…Moreover, our in vivo and in vitro studies suggest that light elicited reprogramming of endothelial metabolism protects the endothelial barrier function during IR-injury. Together with previous studies on myocardial IR-injury (Yang et al, 2016), these studies highlight the importance of cardiac endothelial metabolism in IR-injury and point towards unrecognized therapeutic strategies for cardiovascular disease using intense light or pharmacological compounds, such as the circadian rhythm enhancer nobiletin Oyama et al, 2018), to increase endothelial PER2 amplitude.…”