Biology subjects

Onishi, H.

Publications and source records attributed to Onishi, H..

5 recordsLinked to original sources

bioRxiv2024

Muscle-derived miR-200a-3p through light-intensity exercise may contribute to improve memory dysfunction in type 2 diabetic mice

BackgroundMemory dysfunction associated with type 2 diabetes mellitus (T2DM) poses a considerable threat to overall well-being. Engaging in light-intensity exercise has been shown to exert favorable effects on hippocampal function and molecular profiles, including Mct2 mRNA and miR-200a-3p. Nonetheless, a comprehensive understanding of the mechanisms underlying the positive impact of light-intensity exercise remains elusive. Here, we assessed the influence of exosomal miR-200a-3p secretion from gastrocnemius muscles in T2DM mice undergoing light-intensity exercise intervention, focusing on its potential to ameliorate memory dysfunction. Basic proceduresWe initially assessed the effects of light-intensity exercise (7.0 m/min for healthy mice, 5.0 m/min for ob/ob mice, 30 min/day, five days/week, over a four-week period) on memory function, hippocampal mRNA associated with memory function, and the secretion of exosomal miR-200a-3p from their gastrocnemius muscle. Subsequently, the impact of a daily intraperitoneal injection of the miR-200a-3p mimic over a four-week duration was investigated, focusing on its influence on hippocampal dysregulation in ob/ob mice. Main findingsThe light-intensity exercise intervention increased gastrocnemius muscle-derived and plasma exosomal miR-200a-3p levels in ob/ob mice, concomitant with improved memory dysfunction. Intriguingly, the daily intraperitoneal injection of mmu-miR-200a-3p mimic also demonstrated an ameliorative effect on memory function in ob/ob mice. Notably, both the exercise intervention and miR-200a-3p mimic treatment induced downregulation in hippocampal Keap1 mRNA and upregulation in mRNA of Hsp90aa1 and Mct2 in ob/ob mice. Principal conclusionsThe current results imply that the augmentation of exosomal miR-200a-3p derived from the gastrocnemius muscle contributes to the amelioration of memory dysfunction in T2DM undergoing light-intensity exercise. Additionally, it is proposed that miR-200a-3p emulates the effects of light-intensity exercise, suggesting a potential therapeutic pathway for addressing hippocampal complications in the context of T2DM.

neuroscience↗

bioRxiv2024

Exercising with virtual reality is potentially better for the working memory and positive mood than cycling alone

Although virtual reality (VR) exercise has attracted attention as a factor in exercise habituation due to its mood-enhancing effects, its impact on brain function remains unclear. This study, involving 23 healthy university students, used functional magnetic resonance imaging (fMRI) to explore how VR exercise affects working memory, a key executive function, and its underlying neural mechanisms. Our findings indicate that a 10-min VR exercise session improved mood (arousal and vitality level) and working memory task performance (3-back task) more effectively than exercise or rest alone. Furthermore, the results confirmed that increased vitality from exercise and VR exercise interventions was associated with improved 3-back task performance. However, specific brain regions contributing to this enhancement remain unidentified. These results highlight VR exercise as the optimal exercise program for enhancing working memory function by increasing vitality level. These insights underscore VRs potential as a novel exercise modality with benefits extending beyond exercise adherence to potentially preventing dementia and depression.

neuroscience↗

bioRxiv2024

Feeding a low-carbohydrate and high-protein diet diminishes working memory in healthy mice: possible involvement of miR-539-3p/Lrp6/Igf1r axis in the hippocampus

A low-carbohydrate and high-protein (LC-HP) diet demonstrates favorable impacts on metabolic parameters, albeit it leads to a decline in hippocampal function among healthy mice. The reduction in working memory induced by LC-HP diets is attributed to the decreased expression of hippocampal IGF-1 receptor (IGF-1R). However, the precise mechanisms underlying this phenomenon remain unexplored. Here, we investigated that by analyzing alterations in hippocampal miRNA profiles. C57BL/6 mice were divided into the LC-HP diet-fed group (25.1% carbohydrate, 57.2% protein, and 17.7% fat as percentages of calories) and the control diet-fed group (58.9% carbohydrate, 24.0% protein, and 17.1% fat as percentages of calories). After four weeks, all mice underwent the Y-maze test, followed by analyses of mRNA and miRNA expressions in the hippocampus. Our investigation revealed that feeding the LC-HP diet suppressed working memory function and hippocampal Igf1r mRNA levels in mice. Sequencing of miRNA demonstrated 17 upregulated and 27 downregulated miRNAs in the hippocampus of LC-HP diet-fed mice. Notably, upregulation of miR-539-3p, predicted to modulate Igf1r gene expression, was observed. Consequently, we found decreased hippocampal mRNA levels of low-density lipoprotein receptor-related protein 6 (Lrp6), a gene modulated by miR-539-3p, in mice fed the LC-HP diet. Furthermore, a significant positive correlation was observed between Lrp6 and Igf1r mRNA levels in the hippocampus. These findings suggest that LC-HP diets may suppress hippocampal function via the miR-539-3p/Lrp6/Igf1r axis, offering a potential target for nutritional strategies to preserve hippocampal health.

neuroscience↗

bioRxiv2022

Castration alters the circadian clock and Ucp1 expression in subcutaneous white adipose tissue of mice

Castration increases the risk of metabolic syndromes in mammals. In addition, recent studies have demonstrated that castration increases the expression of Ucp1 in subcutaneous white adipose tissue (scWAT). However, how castration leads to thermogenic aberration remains poorly understood. Here, we found that castrated mice showed elevated Ucp1 expression in scWAT in response to cold exposure with an increase in body temperature in the light phase and a reduction in body weight gain with fat reduction despite showing no alterations in food intake, locomotor activity in a novel environment, and gastrocnemius muscle weight. We also analyzed the circadian behavioral rhythm and the expression rhythm of clock genes in the suprachiasmatic nucleus (SCN) and scWAT. We found that castrated mice showed fluctuations in circadian locomotor activity and a decrease in the expression rhythm of clock genes in the SCN (clock) and scWAT (Bmal1 and Per2). Moreover, the expression of Ucp1 in scWAT was rhythmic, and it was increased in castrated mice, while the expression of clock genes was decreased. These results indicate that castration may impact browning in scWAT through variations in the circadian clock and Ucp1 expression.

physiology↗

bioRxiv2021

Reward priming differentially modulates enhancement and inhibition in auditory decision-making

In cognitive sciences, rewards, such as money and food, play a fundamental role in individuals daily lives and well-being. Moreover, rewards that are irrelevant to the task alter individuals behavior. However, it is unclear whether explicit knowledge of reward irrelevancy has an impact on reward priming enhancements and inhibition. In this study, an auditory change-detection task with task-irrelevant rewards was introduced. The participants were informed explicitly in advance that the rewards would be given randomly. The results revealed that while inhibition related to reward priming only occurred when the participants were explicitly informed about rewards, implicit instruction thereof resulted in enhancement and inhibition associated with reward priming. These findings highlight the contribution of explicit information about rewards associated with auditory decisions.

neuroscience↗