Yu Tahara 교수

Microbiota-derived short-chain fatty acids (SCFAs) and organic acids produced by the fermentation of non-digestible fibre can communicate from the microbiome to host tissues and modulate homeostasis in mammals. The microbiome has circadian rhythmicity and helps the host circadian clock function. We investigated the effect of SCFA or fibre-containing diets on circadian clock phase adjustment in mouse peripheral tissues (liver, kidney, and submandibular gland). Initially, caecal SCFA concentration

The mammalian circadian clock regulates day-night fluctuations in various physiological processes. The circadian clock consists of the central clock in the suprachiasmatic nucleus of the hypothalamus and peripheral clocks in peripheral tissues. External environmental cues, including light/dark cycles, food intake, stress, and exercise, provide important information for adjusting clock phases. This review focuses on stress and exercise as potent entrainment signals for both central and peripheral

The effects of acute stress on the peripheral circadian system are not well understood in vivo. Here, we show that sub-acute stress caused by restraint or social defeat potently altered clock gene expression in the peripheral tissues of mice. In these peripheral tissues, as well as the hippocampus and cortex, stressful stimuli induced time-of-day-dependent phase-advances or -delays in rhythmic clock gene expression patterns; however, such changes were not observed in the suprachiasmatic nucleus,

The mammalian circadian clock is known to be entrained by both a daily light-dark cycle and daily feeding cycle. However, the mechanisms of feeding-induced entrainment are not as fully understood as those of light entrainment. To elucidate the first step of entrainment of the liver clock, we identified the circadian clock gene(s) that show both phase advance and acute change of gene expression during the early term of the daytime refeeding schedule in mice. The expressions of liver Per2 and Rev-

The circadian clock system in mammals drives many physiological processes including the daily rhythms of sleep-wake behavior, hormonal secretion, and metabolism. This system responds to daily environmental changes, such as the light-dark cycle, food intake, and drug administration. In this review, we focus on the central and peripheral circadian clock systems in response to drugs, food, and nutrition. We also discuss the adaptation and anticipation mechanisms of our body with regard to clock sys

The ability of the circadian clock to adapt to environmental changes is critical for maintaining homeostasis, preventing disease, and limiting the detrimental effects of aging. To date, little is known about age-related changes in the entrainment of peripheral clocks to external cues. We therefore evaluated the ability of the peripheral clocks of the kidney, liver, and submandibular gland to be entrained by external stimuli including light, food, stress, and exercise in young versus aged mice us

We propose a method to improve the enhanced permeability and retention (EPR) effect of nanomedicines based on tumor-specific vasodilation using a nitric oxide (NO) donor-containing liposome. NONOate, a typical NO donor, was incorporated into a PEGylated liposome to retard the protonation-induced release of NO from NONOate by the protecting lipid bilayer membrane. The NONOate-containing liposome (NONOate-LP) showed similar blood retention to an empty PEGylated liposome but almost twice the amount

Breakfast skipping and nighttime snacking have been identified as risk factors for obesity, diabetes, and cardiovascular diseases. However, the effects of irregularity of meal timing on health and daily quality of life are still unclear. In this study, a web-based self-administered questionnaire survey was conducted involving 4490 workers (73.3% males; average age = 47.4 ± 0.1 years) in Japan to investigate the association between meal habits, health, and social relationships. This study identif

Restricted feeding induces anticipatory activity rhythm and also entrains the peripheral circadian clocks, although the underlying brain mechanisms have not been fully elucidated. The dorsomedial hypothalamus (DMH) has been implicated in the regulation of restricted feeding-induced anticipatory activity rhythms (FAA), but the role of the DMH in restricted feeding- induced entrainment of peripheral circadian clocks is still unknown. In the present study, the role of the DMH in entrainment of the

Although there is cumulative evidence showing a relationship between late chronotype and obesity, it is still unclear about the potential benefit of the chronotype management to control body weight. Thus, to the best of our knowledge, this is the first study investigating the association between chronotype and weight changes by leveraging a large cohort.