Circadian MicroRNAs in Cardioprotection.
AI Summary
This review explores the connection between light-regulated circadian rhythms and heart protection, with potential implications for morning sunlight exposure. The study suggests that the circadian rhythm protein Period 2 (PER2), which is regulated by light, provides natural protection against heart attacks. Researchers found that among 352 microRNAs studied, miR-21 was identified as a key PER2-dependent microRNA that helps mediate this cardioprotective effect. The research indicates that heart attacks show circadian patterns in their timing of onset, highlighting the importance of our body's internal clock in cardiovascular health. Notably, the study suggests that intense light therapy could potentially enhance miR-21 activity, which may strengthen the heart's natural protective mechanisms. While this research focuses on therapeutic light interventions rather than natural morning sunlight specifically, it provides scientific foundation for how light exposure influences cardiovascular protection through circadian rhythm regulation. The findings are preliminary and focus on identifying potential therapeutic pathways rather than providing direct clinical applications for morning sunlight exposure.
Key Findings
- The light-regulated circadian protein Period 2 (PER2) provides natural cardioprotection from heart attacks
- Heart attacks exhibit circadian periodicity in their timing of onset
- MicroRNA miR-21 was identified as a key PER2-dependent molecule that mediates cardioprotective effects
- Intense light therapy was suggested as a potential strategy to enhance miR-21 activity in humans
Abstract
The most dramatic feature of life on Earth is our adaptation to the cycle of day and night. Throughout evolutionary time, almost all living organisms developed a molecular clock linked to the light-dark cycles of the sun. In present time, we know that this molecular clock is crucial to maintain metabolic and physiological homeostasis. Indeed, a dysregulated molecular clockwork is a major contributing factor to many metabolic diseases. In fact, the time of onset of acute myocardial infarction exhibits a circadian periodicity and recent studies have found that the light regulated circadian rhythm protein Period 2 (PER2) elicits endogenous cardioprotection from ischemia. Manipulating the molecular clockwork may prove beneficial during myocardial ischemia in humans. MicroRNAs are small non-coding RNA molecules capable of silencing messenger RNA (mRNA) targets. MicroRNA dysregulation has been linked to cancer development, cardiovascular and neurological diseases, lipid metabolism, and impaired immunity. Therefore, microRNAs are gaining interest as putative novel disease biomarkers and therapeutic targets. To identify circadian microRNA-based cardioprotective pathways, a recent study evaluated transcriptional changes of PER2 dependent microRNAs during myocardial ischemia. Out of 352 most abundantly expressed microRNAs, miR-21 was amongst the top PER2 dependent microRNAs and was shown to mediate PER2 elicited cardioprotection. Further analysis suggested circadian entrainment via intense light therapy to be a potential strategy to enhance miR-21 activity in humans. In this review, we will focus on circadian microRNAs in the context of cardioprotection and will highlight new discoveries, which could lead to novel therapeutic concepts to treat myocardial ischemia.
Authors
Yoshimasa Oyama, Colleen Marie Bartman, Jennifer Gile, Tobias Eckle