Biology subjects

Izumo, M.

Publications and source records attributed to Izumo, M..

3 recordsLinked to original sources

bioRxiv2026

Mice sense Moon and Sun

Life on earth has always been exposed to the fluctuating Earth's magnetic field, but a magnetic sense affecting behavior has been debated for mammals. We here report that mice, kept under constant laboratory conditions, showed fluctuations in spontaneous behavioral activity with a periodicity of ~14 and ~28 days. This was confirmed in nine cohorts from four facilities on two continents, covering 3 to 41 months. Such oscillations were also maintained in brain Bmal1 knockout mice lacking circadian rhythms, suggesting independence of the circadian clock. The behavioral activity peaked around full and new Moon, and showed a strong alignment with the periodic geomagnetic fluctuations originating in the Earth's iono- and magnetosphere that are modulated by solar rotation and the orbital motion of the Moon. In the ultradian range, this alignment persisted in CRY1/2 knockout mice, suggesting that solar-lunar-driven geomagnetic fluctuations can modulate behavior rhythms independently of CRY1/2.

neuroscience↗

bioRxiv2022

Gut Microbes and the Liver Circadian Clock Partition Glucose and Lipid Metabolism

Circadian rhythms govern glucose homeostasis, and their dysregulation leads to complex metabolic diseases. Gut microbes also exhibit diurnal rhythms that influence host circadian networks and metabolic processes, yet underlying mechanisms remain elusive. Here, we show hierarchical, bi-directional communication between the liver circadian clock, gut microbes, and glucose homeostasis in mice. The liver clock, but not the forebrain clock, requires gut microbes to drive glucose clearance and gluconeogenesis. Liver clock dysfunctionality expands proportions and abundances of oscillating microbial features by two-fold relative to controls. The liver clock is the primary driver of differential and rhythmic hepatic expression of glucose and fatty acid metabolic pathways. Absent the liver clock, gut microbes provide secondary cues that dampen these rhythms, resulting in reduced utilization of lipids as fuel relative to carbohydrates. Together, the liver clock transduces signals from gut microbes necessary to regulate glucose and lipid metabolism and meet energy demands over 24 hours. HighlightsThe liver circadian clock is autonomous from the central clock in metabolic regulation Liver clock and gut microbes interact to direct hepatic glucose and lipid metabolism Reciprocating host-microbe interactions drive rhythmic hepatic transcription Perturbed liver Bmal1 results in chaotic downstream oscillators and metabolism

physiology↗

bioRxiv2018

Cell-autonomous regulation of astrocyte activation by the circadian clock protein BMAL1

Circadian clock dysfunction is a common symptom of aging and neurodegenerative diseases, though its impact on brain health is poorly understood. Astrocyte activation occurs in response to diverse insults, and plays a critical role in brain health and disease. We report that the core clock protein BMAL1 regulates astrogliosis in a synergistic manner via a cell-autonomous mechanism, and via a lesser non-cell-autonomous signal from neurons. Astrocyte-specific Bmal1 deletion induces astrocyte activation in vitro and in vivo, mediated in part by suppression of glutathione-s-transferase signaling. Functionally, loss of Bmal1 in astrocytes promotes neuronal death in vitro. Our results demonstrate that the core clock protein BMAL1 regulates astrocyte activation and function in vivo, elucidating a novel mechanism by which the circadian clock could influence many aspects of brain function and neurologic disease.

neuroscience↗