Review
Biochemistry & Molecular Biology
Qingqing Lu, Jin Young Kim
Summary: The brain is a complex structure composed of hundreds of regions forming networks to cooperate body functions. Understanding how different brain regions communicate with each other and with peripheral organs is crucial for understanding human physiology. The circadian clock, governed by the SCN in the brain, plays a key role in maintaining daily physiological rhythms and metabolism.
Review
Biochemistry & Molecular Biology
Amy R. Poe, Kyla D. Mace, Matthew S. Kayser
Summary: Research shows that while molecular circadian rhythms are present in early development, most behavioral rhythms, like sleep-wake cycles, only emerge later. The study focuses on the development of circadian clocks, outputs, and behaviors in various species, with a specific emphasis on Drosophila. Potential mechanisms for communication between central clocks and circadian output sites are explored, along with the evolutionary perspective on why behavioral rhythms emerge long after central clocks begin functioning.
Review
Biochemistry & Molecular Biology
Abdurrahman Coskun, Atefeh Zarepour, Ali Zarrabi
Summary: The concentration of biomolecules in living systems exhibits systematic and random variations. Systematic variations can be classified into ultradian, circadian, and infradian rhythms based on their frequency, while random biological variations include variations between individuals and within individuals. Physiological rhythms and random biological variations are important for predictive, preventive, and personalized laboratory medicine.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Review
Biochemistry & Molecular Biology
Leonardo Vinicius Monteiro de Assis, Henrik Oster
Summary: The circadian clock plays a crucial role in maintaining systemic homeostasis by synchronizing with environmental challenges and biological processes. Communication between central and peripheral clocks is essential, and the modulation of metabolic organs by the circadian clock is a key aspect of its function. Recent studies on communication between peripheral tissues provide new insights into circadian organization.
CELLULAR AND MOLECULAR LIFE SCIENCES
(2021)
Review
Biochemistry & Molecular Biology
Evrim Yildirim, Rachel Curtis, Dae-Sung Hwangbo
Summary: Biological clocks are essential mechanisms that synchronize physiological and behavioral processes with external cues to ensure organisms' fitness and survival. While the central clock in the brain drives daily activity rhythms, peripheral tissues have their own clock systems generating metabolic and physiological rhythms. The fruit fly Drosophila melanogaster has been a widely studied model organism for investigating the mechanism and functions of circadian clocks.
Review
Neurosciences
Javier Cavieres-Lepe, John Ewer
Summary: Circadian rhythms in animals are driven by intracellular transcriptional/translational feedback loops, and Ca2+ signaling plays a crucial role in regulating the molecular rhythms and behavior. There is evidence of reciprocal interaction between Ca2+ signaling and circadian clocks, with genes encoding Ca2+ channels and binding proteins showing rhythmic expression and disruption affecting circadian function. Additionally, Ca2+ rhythms and signaling pathways modulate clock gene expression at transcriptional and post-translational levels, potentially impacting pharmacotherapy and clinical interventions.
FRONTIERS IN MOLECULAR NEUROSCIENCE
(2021)
Review
Physiology
Maria Luisa Jabbur, Carl Hirschie Johnson
Summary: This paper reviews the literature on the ecology and evolution of circadian clocks, with a special focus on cyanobacteria as model organisms. It discusses the role of circadian clocks in adaptive fitness and their potential response to climate change. The paper also explores the oldest known circadian clock and its evolution under early Earth conditions.
FRONTIERS IN PHYSIOLOGY
(2022)
Review
Cell Biology
Rona Aviram, Yaarit Adamovich, Gad Asher
Summary: Circadian clocks are present in most light-sensitive organisms, leading to circadian rhythmicity in various biological functions, including intracellular organelles. Although there have been studies on the rhythmicity of organelles, there still exist knowledge gaps, particularly in the understanding of molecular mechanisms and functional significance.
Review
Physiology
Yaarit Adamovich, Vaishnavi Dandavate, Gad Asher
Summary: This article reviews the interaction between the circadian clock and the oxygen-signalling pathway in mammals under normal and pathological conditions. Evidence suggests that the circadian clock can sense and regulate changes in oxygen levels through the HIF-1 signalling pathway, further influencing the rhythmicity of the clock itself.
Review
Cardiac & Cardiovascular Systems
Nadim El Jamal, Ronan Lordan, Sarah L. Teegarden, Tilo Grosser, Garret FitzGerald
Summary: Cardiac physiology is regulated by autonomous molecular clocks and the suprachiasmatic nucleus, exhibiting diurnal rhythms. Disrupting molecular clocks can lead to heart failure, and the time of day can condition myocardial response to injury. Human studies support the involvement of molecular clocks and circadian rhythms in the pathogenesis of heart failure. Certain circadian rhythms are maintained in heart failure patients, which can guide optimal timing of therapy. Manipulation of circadian rhythms and molecular clocks show promise in the prevention and treatment of heart failure.
CIRCULATION RESEARCH
(2023)
Article
Biology
Peter S. Johnstone, Maite Ogueta, Olga Akay, Inan Top, Sheyum Syed, Ralf Stanewsky, Deniz Top
Summary: This study developed a new method, called Locally Activatable BioLuminescence (LABL), to directly measure the transcriptional oscillation of specific neuronal and peripheral clocks in intact Drosophila. The results showed that loss of the receptor for the circadian neurotransmitter PDF only disrupted locomotor activity but not all tissue-specific circadian clocks.
Review
Endocrinology & Metabolism
Marine Adlanmerini, Mitchell A. Lazar
Summary: REV-ERB nuclear receptors are potent transcriptional repressors that play crucial roles in the mammalian molecular clock and metabolism. Deletion of REV-ERB alpha and REV-ERB beta in a tissue-specific manner in mice has provided insights into their specific functions in regulating clock mechanisms and circadian metabolism. Recent findings highlight the importance of REV-ERBs as key circadian regulators in various tissues, controlling overlapping and distinct processes that are essential for maintaining normal physiology and protecting against metabolic dysfunction.
Article
Physics, Fluids & Plasmas
Lukas Oberreiter, Udo Seifert, Andre C. Barato
Summary: Biochemical clocks are crucial for all living systems and can only oscillate coherently for a limited number of times when isolated from external signals and subject to fluctuations. Moreover, these clocks can only oscillate if they consume free energy. We propose a universal bound that determines the minimum amount of free energy required for a certain number of coherent oscillations.
Review
Behavioral Sciences
Jacob R. Bumgarner, William H. Walker, Randy J. Nelson
Summary: The circadian rhythms of pain are not produced by a single locus, but are a complex result of distributed rhythms throughout the pain system and interacting systems, including the opioid, endocrine, and immune systems.
NEUROSCIENCE AND BIOBEHAVIORAL REVIEWS
(2021)
Review
Physiology
Anna-Marie Finger, Achim Kramer
Summary: The endogenous circadian clock system in humans and other mammals is crucial for health, but modern lifestyles with artificial lighting, shift work, and travel across time zones can disrupt this system and lead to associated diseases. This review highlights the importance of a functional clock machinery and alignment between body clocks, as well as the impact of circadian disruption on health.
