博士 (学術), 東京大学

骨格筋

脂肪酸代謝

乳酸

ミトコンドリア

運動

ライフサイエンス, スポーツ科学

2017年10月 - 現在
電気通信大学, 情報理工学域 基盤理工学専攻 化学生命工学プログラム, 准教授

2017年10月 - 現在
電気通信大学, 情報理工学域 共通教育部 健康・スポーツ科学部会, 准教授

2017年04月 - 2017年09月
東京大学, 大学院理学系研究科生物科学専攻, 特任助教

2014年04月 - 2017年03月
東京大学, 大学院理学系研究科生物科学専攻, 日本学術振興会 特別研究員PD

2011年04月 - 2014年03月
東京大学, 大学院・総合文化研究科, 助教

2008年04月 - 2011年03月
東京大学, 大学院総合文化研究科, 広域科学専攻 博士課程

2006年04月 - 2008年03月
東京大学, 大学院総合文化研究科, 広域科学専攻 修士課程

2001年04月 - 2005年03月
筑波大学, 体育専門学群

Time-series transcriptomics reveals distinctive mRNA expression dynamics associated with gene ontology specificity and protein expression in skeletal muscle after electrical stimulation-induced resistance exercise.
Tatsuya Kusano; Yuta Sotani; Reo Takeda; Atsushi Hatano; Kentaro Kawata; Ryotaro Kano; Masaki Matsumoto; Yutaka Kano; Daisuke Hoshino
FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 38巻, 22号, 掲載ページ e70153, 出版日 2024年11月30日, 国際誌, Resistance exercise upregulates and downregulates the expression of a wide range of genes in skeletal muscle. However, detailed analysis of mRNA dynamics such as response rates and temporal patterns of the transcriptome after resistance exercise has not been performed. We aimed to clarify the dynamics of time-series transcriptomics after resistance exercise. We used electrical stimulation-induced muscle contraction as a resistance exercise model (5 sets × 10 times of 3 s of 100-Hz electrical stimulation) on the tibialis anterior muscle of rats and measured the transcriptome in the muscle before and at 0, 1, 3, 6, and 12 h after muscle contractions by RNA sequencing. We also examined the relationship between the parameters of mRNA dynamics and the increase in protein expression at 12 h after muscle contractions. We found that the function of the upregulated genes differed after muscle contractions depending on their response rate. Genes related to muscle differentiation and response to mechanical stimulus were enriched in the sustainedly upregulated genes. Furthermore, there was a positive correlation between the magnitude of upregulated mRNA expression and the corresponding protein expression level at 12 h after muscle contractions. Although it has been theoretically suggested, this study experimentally demonstrated that the magnitude of the mRNA response after electrical stimulation-induced resistance exercise contributes to skeletal muscle adaptation via increases in protein expression. These findings suggest that mRNA expression dynamics such as response rate, a sustained upregulated expression pattern, and the magnitude of the response contribute to mechanisms underlying adaptation to resistance exercise.
研究論文（学術雑誌）, 英語

In vivo intracellular Ca2+ profiles after eccentric rat muscle contractions: Addressing the mechanistic bases for repeated bout protection.
Ayaka Tabuchi; Yudai Kikuchi; Ryo Takagi; Yoshinori Tanaka; Daisuke Hoshino; David C Poole; Yutaka Kano
Journal of applied physiology (Bethesda, Md. : 1985), 出版日 2024年11月15日, 国際誌, Eccentric contractions (ECC) are accompanied by accumulation of intracellular calcium ions ([Ca2+]i) and induce skeletal muscle damage. Suppressed muscle damage in repeated bouts of ECC is well characterized, however, whether it is mediated by altered Ca2+ profiles remains unknown. PURPOSE: We tested the hypothesis that repeated ECC suppresses Ca2+ accumulation via adaptions in Ca2+ regulation. METHODS: Male Wistar rats were divided into two groups: ECC single bout (ECC-SB) and repeated bout (ECC-RB). Tibialis anterior (TA) muscles were subjected to ECC (40 times, 5 sets) once (ECC-SB), or twice 14 days apart (ECC-RB). Under anesthesia, the TA muscle was loaded with Ca2+ indicator Fura-2 AM and the 340/380 nm ratio was evaluated as [Ca2+]i. Ca2+ handling proteins were measured by western blots. RESULTS: ECC induced [Ca2+]i increase in both groups, but ECC-RB evinced a markedly suppressed [Ca2+]i (Time: P < 0.01, Group: P = 0.0357). 5 hours post-ECC, in contrast to the localized [Ca2+]i accumulation in ECC-SB, ECC-RB exhibited lower and more uniform [Ca2+]i (P < 0.01). In ECC-RB mitochondria Ca2+ uniporter complex components, MCU and MICU2, were significantly increased pre-second ECC bout (P < 0.01) and both SERCA1 and MICU1 were better preserved after contractions (P < 0.01). CONCLUSION: 14 days after novel ECC skeletal muscle mitochondrial Ca2+ regulating proteins were elevated. Following subsequent ECC [Ca2+]i accumulation and muscle damage were suppressed and SERCA1 and MICU1 preserved. These findings suggest that tolerance to a subsequent ECC bout is driven, at least in part, by enhanced mitochondrial and SR Ca2+ regulation.
研究論文（学術雑誌）, 英語

Eccentric contraction increases hydrogen peroxide levels and alters gene expression through Nox2 in skeletal muscle of male mice
Ryotaro Kano; Tatsuya Kusano; Reo Takeda; Hideki Shirakawa; David C. Poole; Yutaka Kano; Daisuke Hoshino
Journal of Applied Physiology, American Physiological Society, 137巻, 3号, 掲載ページ 778-788, 出版日 2024年09月01日, This in vivo model successfully characterized the effects of eccentric (ECC) and concentric (CONC) contractions on cytosolic and mitochondrial [H₂O₂] in mouse skeletal muscle. Compared with CONC, ECC induced higher and more sustained [H₂O₂]_cyto—an effect that was abolished by Nox2 inhibition. ECC-induced [H₂O₂]_cyto elevations were requisite for altered gene expression.
研究論文（学術雑誌）

Cmah deficiency blunts cellular senescence in adipose tissues and improves whole-body glucose metabolism in aged mice.
Reo Takeda; Ayaka Tabuchi; Yudai Nonaka; Ryotaro Kano; Mizuki Sudo; Yutaka Kano; Daisuke Hoshino
Geriatrics & gerontology international, 出版日 2023年11月15日, 国内誌, AIM: Cytidine monophosphate-N-acetylneuraminic acid (Neu5Ac) hydroxylase (Cmah) is an enzyme, which converts Neu5Ac to the sialic acid Neu5Gc. Neu5Gc is thought to increase inflammatory cytokines, which are, in part, produced in senescent cells of adipose tissues. Cellular senescence in adipose tissues induces whole-body aging and impaired glucose metabolism. Therefore, we hypothesized that Cmah deficiency would prevent cellular senescence in adipose tissues and impaired glucose metabolism. METHODS: Wild-type (WT) and Cmah knockout (KO) mice aged 24-25 months were used. Whole-body metabolism was assessed using a metabolic gas analysis system. We measured blood glucose and insulin concentrations after oral glucose administration. The size of the lipid droplets in the liver was quantified. Markers of cellular senescence and senescence-associated secretory phenotypes were measured in adipose tissues. RESULTS: Cmah KO had significantly increased VO2 and energy expenditure (P < 0.01). Unlike glucose, the insulin concentration after oral glucose administration was significantly lower in the Cmah KO group than in the WT group (P < 0.001). Lipid droplets in the liver were significantly lower in the Cmah KO group than in the WT group (P < 0.05). The markers of cellular senescence and senescence-associated secretory phenotypes in the adipose tissues were significantly lower in the Cmah KO group than in the WT group (P < 0.05). CONCLUSIONS: Cmah deficiency blunted cellular senescence in adipose tissues and improved whole-body glucose metabolism. These characteristics in aged Cmah KO mice might be associated with higher energy expenditure. Geriatr Gerontol Int 2023; ••: ••-••.
研究論文（学術雑誌）, 英語

Cooling of male rat skeletal muscle during endurance-like contraction attenuates contraction-induced PGC-1α mRNA expression.
Daisuke Hoshino; Ryota Wada; Yutaro Mori; Reo Takeda; Yudai Nonaka; Ryotaro Kano; Ryo Takagi; Yutaka Kano
Physiological reports, 11巻, 21号, 掲載ページ e15867, 出版日 2023年11月, 国際誌, This study aimed to determine effects of cooling on contraction-induced peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) and vascular endothelial growth factor (VEGF) gene expression, phosphorylations of its related protein kinases, and metabolic responses. Male rats were separated into two groups; room temperature (RT) or ice-treated (COLD) on the right tibialis anterior (TA). The TA was contracted isometrically using nerve electrical stimulation (1-s stimulation × 30 contractions, with 1-s intervals, for 10 sets with 1-min intervals). The TA was treated before the contraction and during 1-min intervals with an ice pack for the COLD group and a water pack at RT for the RT group. The muscle temperature of the COLD group decreased to 19.42 ± 0.44°C (p < 0.0001, -36.4%) compared with the RT group after the experimental protocol. An increase in mRNA expression level of PGC-1α, not VEGF, after muscle contractions was significantly lower in the COLD group than in the RT group (p < 0.0001, -63.0%). An increase in phosphorylated AMP-activated kinase (AMPK) (p = 0.0037, -28.8%) and a decrease in glycogen concentration (p = 0.0231, +106.3%) after muscle contraction were also significantly inhibited by cooling. Collectively, muscle cooling attenuated the post-contraction increases in PGC-1α mRNA expression coinciding with decreases in AMPK phosphorylation and glycogen degradation.
研究論文（学術雑誌）, 英語

In vivo cytosolic H2O2 changes and Ca2+ homeostasis in mouse skeletal muscle.
Ryotaro Kano; Ayaka Tabuchi; Yoshinori Tanaka; Hideki Shirakawa; Daisuke Hoshino; David C Poole; Yutaka Kano
American journal of physiology. Regulatory, integrative and comparative physiology, 出版日 2023年10月30日, 査読付, 国際誌, Hydrogen peroxide (H2O2) and calcium ions (Ca2+) are functional regulators of skeletal muscle contraction and metabolism. Although H2O2 is one of the activators of the type-1 ryanodine receptor (RyR1) in the Ca2+ release channel, the interdependence between H2O2 and Ca2+ dynamics remains unclear. This study tested the following hypotheses using an in vivo model of mouse tibialis anterior (TA) skeletal muscle. 1. Under resting conditions, elevated cytosolic H2O2 concentration ([H2O2]cyto) leads to a concentration-dependent increase in cytosolic Ca2+concentration ([Ca2+]cyto) through its effect on RyR1. 2. In hypoxia (cardiac arrest) and muscle contractions (electrical stimulation), increased [H2O2]cyto induce Ca2+ accumulation. Cytosolic H2O2 (HyPer7) and Ca2+ (Fura-2) dynamics were resolved by TA bioimaging in C57BL/6J male mice under four conditions: Elevated exogenous H2O2, Cardiac arrest, Twitch and Tetanic contractions. Exogenous H2O2 (0.1-100mM) induced a concentration-dependent increase in [H2O2]cyto (+55%,0.1mM; +280%,100mM) and an increase in [Ca2+]cyto (+3%,1.0mM; +8%,10mM). This increase in [Ca2+]cyto was inhibited by pharmacological inhibition of RyR1 by dantrolene. Cardiac arrest-induced hypoxia increased [H2O2]cyto (+33%) and [Ca2+]cyto (+20%) 50min post-cardiac arrest. Compared to exogenous 1.0mM H2O2 condition, [H2O2]cyto after tetanic contractions rose less than one-tenth as much, while [Ca2+]cyto was 4.7-fold higher. In conclusion, substantial increases in [H2O2]cyto levels evoke only modest Ca2+ accumulation via their effect on the sarcoplasmic reticulum RyR1. On the other hand, contrary to hypoxia secondary to cardiac arrest, increases in [H2O2]cyto from contractions are small, indicating that H2O2 generation is unlikely to be a primary factor driving the significant Ca2+ accumulation after, especially tetanic, muscle contractions.
研究論文（学術雑誌）, 英語

高圧高酸素処置が運動後の筋グリコーゲン回復に及ぼす影響
野中 雄大; 竹田 怜央; 小間 陸嗣; 狩野 遼太郎; 柳下 和慶; 芝口 翼; 増田 和実; 狩野 豊; 星野 太佑
体力科学, (一社)日本体力医学会, 72巻, 4号, 掲載ページ 331-331, 出版日 2023年08月
日本語

Chronic repetitive cooling and caffeine-induced intracellular Ca²⁺ elevation differentially impact adaptations in slow- and fast-twitch rat skeletal muscles
Ryo Takagi; Ayaka Tabuchi; Kosei Hayakawa; Shion Osana; Hiroya Yabuta; Daisuke Hoshino; David C. Poole; Yutaka Kano
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, American Physiological Society, 出版日 2023年06月19日, Intracellular Ca²⁺ concentration ([Ca²⁺]i) is considered important in the regulation of skeletal muscle mass. This study tested the hypothesis that chronic repeated cooling and/or caffeine ingestion would acutely increase [Ca²⁺]i and hypertrophy muscles potentially in a fiber type-dependent manner. Control rats and those fed caffeine, were subjected to repeated bidiurnal treatments of percutaneous icing, under anaesthesia, to reduce the muscle temperature below ~5°C. The predominantly fast twitch tibialis anterior (TA) and slow twitch soleus (SOL) muscles were evaluated after 28 days intervention. The [Ca²⁺]i elevating response to icing was enhanced by caffeine loading only in the SOL muscle, with the response present across a significantly higher temperature range than in the TA muscle under caffeine loading conditions. In both the TA and SOL muscles, myofiber cross-sectional area (CSA) was decreased by chronic caffeine treatment (mean reductions of 10.5% and 20.4%, respectively). However, in the TA , but not the SOL, CSA was restored by icing (+15.4 ± 4.3% vs. non-iced, P<0.01). In the SOL but not TA, icing+caffeine increased myofiber number (20.5 ± 6.7%, P<0.05) and satellite cell density (2.5 ± 0.3-fold) in cross sections. These contrasting muscle responses to cooling and caffeine may reflect fiber-type specific [Ca²⁺]i responses and/or differential responses to elevated [Ca²⁺]i.
研究論文（学術雑誌）

Branched-chain amino acid supplementation suppresses the detraining-induced reduction of mitochondrial content in mouse skeletal muscle.
Yutaka Matsunaga; Yuki Tamura; Kenya Takahashi; Yu Kitaoka; Yumiko Takahashi; Daisuke Hoshino; Tomoyasu Kadoguchi; Hideo Hatta
FASEB journal : official publication of the Federation of American Societies for Experimental Biology, 36巻, 12号, 掲載ページ e22628, 出版日 2022年12月, 国際誌, Exercise training enhances oxidative capacity whereas detraining reduces mitochondrial content in skeletal muscle. The strategy to suppress the detraining-induced reduction of mitochondrial content has not been fully elucidated. As previous studies reported that branched-chain amino acid (BCAA) ingestion increased mitochondrial content in skeletal muscle, we evaluated whether BCAA supplementation could suppress the detraining-induced reduction of mitochondrial content. Six-week-old male Institute of Cancer Research (ICR) mice were randomly divided into four groups as follows: control (Con), endurance training (Tr), detraining (DeTr), and detraining with BCAA supplementation (DeTr + BCAA). Mice in Tr, DeTr, and DeTr + BCAA performed treadmill running exercises [20-30 m/min, 60 min, 5 times/week, 4 weeks]. Then, mice in DeTr and DeTr + BCAA were administered with water or BCAA [0.6 mg/g of body weight, twice daily] for 2 weeks of detraining. In whole skeletal muscle, mitochondrial enzyme activities and protein content were decreased after 2 weeks of detraining, but the reduction was suppressed by BCAA supplementation. Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) protein content, a master regulator of mitochondrial biogenesis, was decreased by detraining irrespective of BCAA ingestion. Regarding mitochondrial degradation, BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3), a mitophagy-related protein, was significantly higher in the Tr group than in the DeTr + BCAA group, but not different from in the DeTr group. With respect to mitochondrial quality, BCAA ingestion did not affect oxygen consumption rate (OCR) and reactive oxygen species (ROS) production in isolated mitochondria. Our findings suggest that BCAA ingestion suppresses the detraining-induced reduction of mitochondrial content partly through inhibiting mitophagy.
研究論文（学術雑誌）, 英語

Effect of endurance training and PGC-1α overexpression on calculated lactate production volume during exercise based on blood lactate concentration.
Reo Takeda; Yudai Nonaka; Katsuyuki Kakinoki; Shinji Miura; Yutaka Kano; Daisuke Hoshino
Scientific reports, 12巻, 1号, 掲載ページ 1635-1635, 出版日 2022年01月31日, 査読付, 国際誌, Lactate production is an important clue for understanding metabolic and signal responses to exercise but its measurement is difficult. Therefore, this study aimed (1) to develop a method of calculating lactate production volume during exercise based on blood lactate concentration and compare the effects between endurance exercise training (EX) and PGC-1α overexpression (OE), (2) to elucidate which proteins and enzymes contribute to changes in lactate production due to EX and muscle PGC-1α OE, and (3) to elucidate the relationship between lactate production volume and signaling phosphorylations involved in mitochondrial biogenesis. EX and PGC-1α OE decreased muscle lactate production volume at the absolute same-intensity exercise, but only PGC-1α OE increased lactate production volume at the relative same-intensity exercise. Multiple linear regression revealed that phosphofructokinase, monocarboxylate transporter (MCT)1, MCT4, and citrate synthase equally contribute to the lactate production volume at high-intensity exercise within physiological adaptations, such as EX, not PGC-1α OE. We found that an exercise intensity-dependent increase in the lactate production volume was associated with a decrease in glycogen concentration and an increase in P-AMPK/T-AMPK. This suggested that the calculated lactate production volume was appropriate and reflected metabolic and signal responses but further modifications are needed for the translation to humans.
研究論文（学術雑誌）, 英語

Short-Term Calorie Restriction Maintains Plasma Insulin Concentrations along with a Reduction in Hepatic Insulin-Degrading Enzyme Levels in db/db Mice.
Yudai Nonaka; Reo Takeda; Yutaka Kano; Daisuke Hoshino
Nutrients, 13巻, 4号, 出版日 2021年04月03日, 国際誌, Maintaining blood insulin levels is important for patients with diabetes because insulin secretion capacity declines with the development of the disease. Calorie restriction (CR) is effective for the improvement of glucose tolerance, but it is not clear whether CR can maintain insulin levels in the late stage of diabetes. We examined the effect of CR on whole-body glucose tolerance and fasting blood insulin concentrations in the late stage of diabetes. Male db/db mice were subjected to either a standard laboratory diet ad libitum for 3 weeks (dbdb group) or 40% CR (dbdb+CR group). CR significantly decreased body mass and epididymal fat weight. Glucose tolerance and fasting glucose levels were significantly improved with 3-week CR. Fasting insulin concentrations were decreased in the dbdb group but were maintained in the dbdb+CR group. CR significantly reduced insulin-degrading enzyme (IDE) levels in the liver, and hepatic IDE levels were significantly positively and negatively correlated with plasma glucose concentrations (area under the curve) after glucose administration and after fasting insulin concentrations, respectively. Therefore, 3-week CR maintained blood insulin levels and improved glucose tolerance with decreased hepatic IDE levels in an animal model of late-stage diabetes.
研究論文（学術雑誌）, 英語

In vivo Ca2+ dynamics during cooling after eccentric contractions in rat skeletal muscle.
Ryo Takagi; Ayaka Tabuchi; Tomoyo Asamura; Seiya Hirayama; Ryo Ikegami; Yoshinori Tanaka; Daisuke Hoshino; David C Poole; Yutaka Kano
American journal of physiology. Regulatory, integrative and comparative physiology, 320巻, 2号, 掲載ページ R129-R137, 出版日 2021年02月01日, 国際誌, The effect of cooling on in vivo intracellular calcium ion concentration [Ca2+]i after eccentric contractions (ECs) remains to be determined. We tested the hypothesis that cryotherapy following ECs promotes an increased [Ca2+]i and induces greater muscle damage in two muscles with substantial IIb and IIx fiber populations. The thin spinotrapezius (SPINO) muscles of Wistar rats were used for in vivo [Ca2+]i imaging, and tibialis anterior (TA) muscles provided greater fidelity and repeatability of contractile function measurements. SPINO [Ca2+]i was estimated using fura 2-AM and the magnitude, location, and temporal profile of [Ca2+]i determined as the temperature near the muscle surface post-ECs was decreased from 30°C (control) to 20°C or 10°C. Subsequently, in the TA, the effect of post-ECs cooling to 10°C on muscle contractile performance was determined at 1 and 2 days after ECs. TA muscle samples were examined by hematoxylin and eosin staining to assess damage. In SPINO, reducing the muscle temperature from 30°C to 10°C post-ECs resulted in a 3.7-fold increase in the spread of high [Ca2+]i sites generated by ECs (P < 0.05). These high [Ca2+]i sites demonstrated partial reversibility when rewarmed to 30°C. Dantrolene, a ryanodine receptor Ca2+ release inhibitor, reduced the presence of high [Ca2+] sites at 10°C. In the TA, cooling exacerbated ECs-induced muscle strength deficits via enhanced muscle fiber damage (P < 0.05). By demonstrating that cooling post-ECs potentiates [Ca2+]i derangements, this in vivo approach supports a putative mechanistic basis for how postexercise cryotherapy might augment muscle fiber damage and decrease subsequent exercise performance.
研究論文（学術雑誌）, 英語

Trans-omic Analysis Reveals ROS-Dependent Pentose Phosphate Pathway Activation after High-Frequency Electrical Stimulation in C2C12 Myotubes.
Daisuke Hoshino; Kentaro Kawata; Katsuyuki Kunida; Atsushi Hatano; Katsuyuki Yugi; Takumi Wada; Masashi Fujii; Takanori Sano; Yuki Ito; Yasuro Furuichi; Yasuko Manabe; Yutaka Suzuki; Nobuharu L Fujii; Tomoyoshi Soga; Shinya Kuroda
iScience, 23巻, 10号, 掲載ページ 101558-101558, 出版日 2020年10月23日, 国際誌, Skeletal muscle adaptation is mediated by cooperative regulation of metabolism, signal transduction, and gene expression. However, the global regulatory mechanism remains unclear. To address this issue, we performed electrical pulse stimulation (EPS) in differentiated C2C12 myotubes at low and high frequency, carried out metabolome and transcriptome analyses, and investigated phosphorylation status of signaling molecules. EPS triggered extensive and specific changes in metabolites, signaling phosphorylation, and gene expression during and after EPS in a frequency-dependent manner. We constructed trans-omic network by integrating these data and found selective activation of the pentose phosphate pathway including metabolites, upstream signaling molecules, and gene expression of metabolic enzymes after high-frequency EPS. We experimentally validated that activation of these molecules after high-frequency EPS was dependent on reactive oxygen species (ROS). Thus, the trans-omic analysis revealed ROS-dependent activation in signal transduction, metabolome, and transcriptome after high-frequency EPS in C2C12 myotubes, shedding light on possible mechanisms of muscle adaptation.
研究論文（学術雑誌）, 英語

Single-Cell Information Analysis Reveals That Skeletal Muscles Incorporate Cell-to-Cell Variability as Information Not Noise.
Takumi Wada; Ken-Ichi Hironaka; Mitsutaka Wataya; Masashi Fujii; Miki Eto; Shinsuke Uda; Daisuke Hoshino; Katsuyuki Kunida; Haruki Inoue; Hiroyuki Kubota; Tsuguto Takizawa; Yasuaki Karasawa; Hirofumi Nakatomi; Nobuhito Saito; Hiroki Hamaguchi; Yasuro Furuichi; Yasuko Manabe; Nobuharu L Fujii; Shinya Kuroda
Cell reports, 32巻, 9号, 掲載ページ 108051-108051, 出版日 2020年09月01日, 国際誌, Cell-to-cell variability in signal transduction in biological systems is often considered noise. However, intercellular variation (i.e., cell-to-cell variability) has the potential to enable individual cells to encode different information. Here, we show that intercellular variation increases information transmission of skeletal muscle. We analyze the responses of multiple cultured myotubes or isolated skeletal muscle fibers as a multiple-cell channel composed of single-cell channels. We find that the multiple-cell channel, which incorporates intercellular variation as information, not noise, transmitted more information in the presence of intercellular variation than in the absence according to the "response diversity effect," increasing in the gradualness of dose response by summing the cell-to-cell variable dose responses. We quantify the information transmission of human facial muscle contraction during intraoperative neurophysiological monitoring and find that information transmission of muscle contraction is comparable to that of a multiple-cell channel. Thus, our data indicate that intercellular variation can increase the information capacity of tissues.
研究論文（学術雑誌）, 英語

Effects of electrical stimulation-induced resistance exercise training on white and brown adipose tissues and plasma meteorin-like concentration in rats.
Yuhei Amano; Yudai Nonaka; Reo Takeda; Yutaka Kano; Daisuke Hoshino
Physiological reports, 8巻, 16号, 掲載ページ e14540, 出版日 2020年08月, 国際誌, Chronic endurance exercise training induces morphological and metabolic alterations including mitochondrial biogenesis in white adipose tissue (WAT) and brown adipose tissue (BAT) in rodents. A myokine called meteorin-like (Metrnl) is associated with morphological and metabolic adaptation and increased in blood after acute resistance exercise. However, the effects of chronic resistance exercise training (RT), which aims to increase muscle mass and strength, on WAT and BAT are unclear. Therefore, we aimed to clarify the effects of RT on morphological and metabolic parameters in WAT and BAT and on plasma Metrnl concentrations. We applied electrical stimulation to both legs of rats as RT three times a week for 4 weeks. RT reduced adipocyte size in subcutaneous WAT but induced no changes in mitochondrial and thermogenesis proteins. In BAT, peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) protein levels and mitochondrial content markers were significantly higher in the RT group compared with the control group. A significant positive correlation was found between the expression of PGC-1α in BAT and plasma Metrnl concentrations. These results suggest that plasma Metrnl is associated with PGC-1α and mitochondrial biogenesis in BAT. This study describes a potential role of RT in preventing metabolic diseases via altering WAT and BAT and increasing plasma Mertnl concentrations.
研究論文（学術雑誌）, 英語

Effects of acute 3-h swimming exercise on insulin secretion capacity of pancreatic islets
Yudai Nonaka; Reo Takeda; Yutaka Kano; Daisuke Hoshino
The Journal of Physical Fitness and Sports Medicine, The Japanese Society of Physical Fitness and Sports Medicine, 9巻, 4号, 掲載ページ 173-179, 出版日 2020年07月25日
研究論文（学術雑誌）

Monitoring and mathematical modeling of mitochondrial ATP in myotubes at single-cell level reveals two distinct population with different kinetics.
Naoki Matsuda; Ken-ichi Hironaka; Masashi Fujii; Takumi Wada; Katsuyuki Kunida; Haruki Inoue; Miki Eto; Daisuke Hoshino; Yasuro Furuichi; Yasuko Manabe; Nobuharu L. Fujii; Hiroyuki Noji; Hiromi Imamura; Shinya Kuroda
Quant. Biol., 8巻, 3号, 掲載ページ 228-237, 出版日 2020年
研究論文（学術雑誌）

Effects of clenbuterol administration on mitochondrial morphology and its regulatory proteins in rat skeletal muscle.
Yu Kitaoka; Daiki Watanabe; Yudai Nonaka; Kazuyoshi Yagishita; Yutaka Kano; Daisuke Hoshino
Physiol Rep, Wiley, 7巻, 19号, 掲載ページ e14266-e14266, 出版日 2019年10月, Clenbuterol induces a slow-to-fast fiber type transition in skeletal muscle. This muscle fiber transition decreased mitochondrial oxidative capacity and respiratory function. We hypothesized that the clenbuterol-mediated reduction in oxidative capacity is associated with the alteration in mitochondrial morphology. To verify this hypothesis, we examined whether clenbuterol alters mitochondrial morphology and mitochondrial regulatory proteins in rat skeletal muscle. Clenbuterol was administered to rats via drinking water (30 mg/L) for 3 weeks. Myosin heavy chain (MHC) isoform composition, mitochondrial morphology, and fusion and fission regulatory protein levels in deep region and superficial region in tibialis anterior (TA) muscles were assessed. Clenbuterol induced the fiber type transition from slow to fast in both the regions of TA. The levels of optic atrophy protein 1, mitofusin 2, and mitochondrial fission 1, but not of dynamin-related protein 1, significantly decreased in deep and superficial muscles after clenbuterol administration (P < 0.01). Also, observation using the transmission electron microscopy showed a decrease in mitochondrial volume (P < 0.05) and an increa
研究論文（学術雑誌）, 英語

Effects of low-carbohydrate diet and resistance exercise training on physical characteristics and concentrations of plasma metabolites and hormones
Sho Ito; Yasuaki Karasawa; Daisuke Hoshino; Masashi Fujii; Miki Eto; Junya Tsuru; Chieko Kashiwado; Shinya Kuroda
Japanese Journal of Physical Fitness and Sports Medicine, The Japanese Society of Physical Fitness and Sports Medicine, 68巻, 3号, 掲載ページ 223-227, 出版日 2019年06月01日
研究論文（学術雑誌）

低糖質食事法およびレジスタンス運動が身体組成と血中代謝物・ホルモン濃度に与える影響
伊藤 翔; 唐沢 康暉; 星野 太佑; 藤井 雅史; 衛藤 樹; 鶴 純也; 柏戸 千絵子; 黒田 真也
体力科学, (一社)日本体力医学会, 68巻, 3号, 掲載ページ 223-227, 出版日 2019年06月, 低糖質食事法およびレジスタンス運動の併用介入が身体組成と血中代謝物およびホルモン濃度に与える影響について検討した。男性7名と女性3名(平均年齢39.6±7.0歳)を対象に、低糖質食事法およびレジスタンス運動を8〜12週間実施した。食事内容は初回の採血終了後から、16回目の運動セッションが終了するまで毎食記録し、自己申告に基づいてトレーナーが日々指導した。体重、BMI、体脂肪量、体脂肪率、筋重量、体水分量は介入後に有意に減少し、筋重量体重比は介入により有意に上昇した。血中代謝物・ホルモンのうち、介入前後で有意に増加した項目はグリシン、3-メチルヒスチジン、無機リン、尿素窒素、尿素窒素クレアチニン比、有意に減少した項目はヘモグロビンA1c、白血球数、β-アミノイソ酪酸、アドレナリン、遊離T4、血中アンモニア、γGTP、コリンエステラーゼ、レプチンであった。
日本語

Accumulation of intramyocyte TRPV1-mediated calcium during heat stress is inhibited by concomitant muscle contractions.
Ryo Ikegami; Hiroaki Eshima; Takuro Mashio; Tomosada Ishiguro; Daisuke Hoshino; David C Poole; Yutaka Kano
Journal of applied physiology (Bethesda, Md. : 1985), 126巻, 3号, 掲載ページ 691-698, 出版日 2019年03月01日, 査読付, 国際誌, Heat stress promotes intramyocyte calcium concentration ([Ca2+]i) accumulation via transient receptor potential vanilloid 1 (TRPV1) channels. We tested the hypothesis that muscle contractile activity concomitant with heat stress would accelerate the increase in [Ca2+]i via TRPV1, further impairing [Ca2+]i homeostasis. Spinotrapezius muscles of adult Wistar rats were exteriorized in vivo and loaded with the fluorescent Ca2+ probe fura 2-AM. Heat stress (muscle surface temperature 40°C) was used as TRPV1 activator. An isometric contraction (100 Hz, 5-10 V, 30 s) was induced electrically concomitant with heat stress. [Ca2+]i was determined for 20 min using in vivo fluorescence microscopy, and the phosphorylation response of TRPV1 was determined by Western blotting. Heat stress induced a significant [Ca2+]i increase of 18.5 ± 8.1% at 20 min and TRPV1 phosphorylation (+231%), which was inhibited by addition of the TRPV1 inhibitor (capsazepine). However, contrary to expectations, the heat stress and isometric contraction condition almost completely inhibited TRPV1 phosphorylation and the consequent [Ca2+]i elevation (<2.8% accumulation during heat stress, P > 0.05). In conclusion, this in vivo physiological model demonstrated that isometric muscle contraction(s) can suppress the phosphorylation response of TRPV1 and maintain [Ca2+]i homeostasis during heat stress. NEW & NOTEWORTHY This investigation is the first document the dynamics of intramyocyte calcium concentration ([Ca2+]i) increase in the myoplasm of skeletal muscle fibers in response to heat stress where the muscle blood flow is preserved. Heat stress at 40°C drives a myoplasmic [Ca2+]i accumulation in concert with transient receptor potential vanilloid 1 (TRPV1) phosphorylation. However, muscle contraction caused TRPV1 channel deactivation by dephosphorylation of TRPV1. TRPV1 inactivation via isometric contraction(s) permits maintenance of [Ca2+]i homeostasis even under high imposed muscle temperature.
研究論文（学術雑誌）, 英語

Automatic Quantitative Segmentation of Myotubes Reveals Single-cell Dynamics of S6 Kinase Activation.
Inoue H; Kunida K; Matsuda N; Hoshino D; Wada T; Imamura H; Noji H; Kuroda S
Cell structure and function, 43巻, 2号, 掲載ページ 153-169, 出版日 2018年08月, 査読付, 国内誌, Automatic cell segmentation is a powerful method for quantifying signaling dynamics at single-cell resolution in live cell fluorescence imaging. Segmentation methods for mononuclear and round shape cells have been developed extensively. However, a segmentation method for elongated polynuclear cells, such as differentiated C2C12 myotubes, has yet to be developed. In addition, myotubes are surrounded by undifferentiated reserve cells, making it difficult to identify background regions and subsequent quantification. Here we developed an automatic quantitative segmentation method for myotubes using watershed segmentation of summed binary images and a two-component Gaussian mixture model. We used time-lapse fluorescence images of differentiated C2C12 cells stably expressing Eevee-S6K, a fluorescence resonance energy transfer (FRET) biosensor of S6 kinase (S6K). Summation of binary images enhanced the contrast between myotubes and reserve cells, permitting detection of a myotube and a myotube center. Using a myotube center instead of a nucleus, individual myotubes could be detected automatically by watershed segmentation. In addition, a background correction using the two-component Gaussian mixture model permitted automatic signal intensity quantification in individual myotubes. Thus, we provide an automatic quantitative segmentation method by combining automatic myotube detection and background correction. Furthermore, this method allowed us to quantify S6K activity in individual myotubes, demonstrating that some of the temporal properties of S6K activity such as peak time and half-life of adaptation show different dose-dependent changes of insulin between cell population and individuals.Key words: time lapse images, cell segmentation, fluorescence resonance energy transfer, C2C12, myotube.
研究論文（学術雑誌）, 英語

Selective control of up-regulated and down-regulated genes by temporal patterns and doses of insulin
Takanori Sano; Kentaro Kawata; Satoshi Ohno; Katsuyuki Yugi; Hiroaki Kakuda; Hiroyuki Kubota; Shinsuke Uda; Masashi Fujii; Katsuyuki Kunida; Daisuke Hoshino; Atsushi Hatano; Yuki Ito; Miharu Sato; Yutaka Suzuki; Shinya Kuroda
Science Signaling, AMER ASSOC ADVANCEMENT SCIENCE, 9巻, 455号, 掲載ページ ra112, 出版日 2016年11月, 査読付, Secretion of insulin transiently increases after eating, resulting in a high circulating concentration. Fasting limits insulin secretion, resulting in a low concentration of insulin in the circulation. We analyzed transcriptional responses to different temporal patterns and doses of insulin in the hepatoma FAO cells and identified 13 up-regulated and 16 down-regulated insulin-responsive genes (IRGs). The up-regulated IRGs responded more rapidly than did the down-regulated IRGs to transient stepwise or pulsatile increases in insulin concentration, whereas the down-regulated IRGs were repressed at lower concentrations of insulin than those required to stimulate the up-regulated IRGs. Mathematical modeling of the insulin response as two stages-(i) insulin signaling to transcription and (ii) transcription and mRNA stability-indicated that the first stage was the more rapid stage for the down-regulated IRGs, whereas the second stage of transcription was the more rapid stage for the up-regulated IRGs. A subset of the IRGs that were up-regulated or down-regulated in the FAO cells was similarly regulated in the livers of rats injected with a single dose of insulin. Thus, not only can cells respond to insulin but they can also interpret the intensity and pattern of signal to produce distinct transcriptional responses. These results provide insight that may be useful in treating obesity and type 2 diabetes associated with aberrant insulin production or tissue responsiveness.
研究論文（学術雑誌）, 英語

Exercise-induced expression of monocarboxylate transporter 2 in the cerebellum and its contribution to motor performance
Daisuke Hoshino; Susumu Setogawa; Yu Kitaoka; Hiroyuki Masuda; Yuki Tamura; Hideo Hatta; Dai Yanagihara
NEUROSCIENCE LETTERS, ELSEVIER IRELAND LTD, 633巻, 掲載ページ 1-6, 出版日 2016年10月, 査読付, Monocarboxylate transporter 2 (MCT2) is an important component of the lactate transport system in neurons of the adult brain. Purkinje cells in the cerebellum have been shown to have high levels of MCT2, suggesting that this protein has a key function in energy metabolism and neuronal activities in these cells. However, it is not known whether inhibition of lactate transport via MCT2 in the cerebellum affects motor performance. To address this question, we examined motor performance in mice following the inhibition of lactate transport via MCT2 in the cerebellum using cc-cyano-4-hydroxycinnamate (4-CIN). 4-CIN or saline was injected into the subarachnoidal space of the cerebellum of mice and motor performance was analyzed by a rotarod test both before and after injection. 4-CIN injection reduced retention time in the rotarod test by approximately 80% at 1 h post-injection compared with pre-injection. No effect was observed at 2 h post-injection or in mice treated with the vehicle control. Because we observed that MCT2 plays an important role in motor performance, we next investigated the effects of acute exercise on MCT2 transcription and protein levels in mice sampled pre-exercise and at 0 and 5 h after 2 h of treadmill running. We found a significant increase in MCT2 mRNA levels, but not of protein levels, in the cerebellum at 5 h after exercise. Our results indicate that lactate transport via MCT2 in the cerebellum may play an important role in motor performance and that exercise can increase MCT2 expression at the transcriptional level. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
研究論文（学術雑誌）, 英語

High-intensity interval training enhances oxidative capacity and substrate availability in skeletal muscle
Hoshino Daisuke; Kitaoka Yu; Hatta Hideo
The Journal of Physical Fitness and Sports Medicine, 一般社団法人日本体力医学会, 5巻, 1号, 掲載ページ 13-23, 出版日 2016年, 査読付, High-intensity interval training (HIIT) consists of repeated short bursts of high-intensity exercise and rest. Here we review recent work focusing on the metabolic adaptations to HIIT, especially in oxidative capacity and substrate availability in skeletal muscle. In this review, HIIT is defined as chronic training, for at least 2 weeks, involving repeated short-duration high-intensity exercise at >85% VO2 max, followed by complete rest or active rest, for any given duration of exercise and rest. First, we describe the effects of HIIT on muscle substrate oxidative metabolism, specifically in terms of mitochondria and substrate transporters. HIIT changes muscle mitochondrial content, function and dynamics. HIIT increases the protein content of transporters of glucose, lactate and fatty acids in skeletal muscle. These adaptations of mitochondria and transporter proteins improve oxidative capacity and substrate availability in skeletal muscle. Second, we introduce a potential mechanism of HIIT-induced adaptations in skeletal muscle, focusing on mitochondrial biogenesis. It is well known that a mechanism of mitochondrial biogenesis involves PGC-1alpha protein and its upstream signaling pathways including Ca2+/calmodulin-dependent protein kinase, AMP-activated protein kinase and mitogen-activated protein kinase p38. Given that mitochondrial biogenesis occurs in an exercise-intensity-dependent manner, mobilization of fast-twitch fibers and lactate accumulation are important. Finally, we discuss the future direction of HIIT research, involving systems biology approaches such as omics technologies and mathematical modeling, which may overcome current limitations and accelerate our understanding of mechanisms of HIIT-induced adaptations.
英語

Effects of decreased lactate accumulation after dichloroacetate administration on exercise training-induced mitochondrial adaptations in mouse skeletal muscle.
Daisuke Hoshino; Yuki Tamura; Hiroyuki Masuda; Yutaka Matsunaga; Hideo Hatta
Physiological reports, 3巻, 9号, 出版日 2015年09月, 査読付, 国際誌, Recent studies suggested that lactate accumulation can be a signal for mitochondrial biogenesis in skeletal muscle. We investigated whether reductions in lactate concentrations in response to dichloroacetate (DCA), an activator of pyruvate dehydrogenase, attenuate mitochondrial adaptations after exercise training in mice. We first confirmed that DCA administration (200 mg/kg BW by i.p. injection) 10 min before exercise decreased muscle and blood lactate concentrations after high-intensity interval exercise (10 bouts of 1 min treadmill running at 40 m/min with a 1 min rest). At the same time, exercise-induced signal cascades did not change by pre-exercise DCA administration. These results suggested that DCA administration affected only lactate concentrations after exercise. We next examined the effects of acute DCA administration on mRNA expressions involved with mitochondrial biogenesis after same high-intensity interval exercise and the effects of chronic DCA administration on mitochondrial adaptations after high-intensity interval training (increasing intensity from 38 to 43 m/min by the end of training period). Acute DCA administration did not change most of the exercise-induced mRNA upregulation. These data suggest that lactate reductions by DCA administration did not affect transcriptional activation after high-intensity interval exercise. However, chronic DCA administration attenuated, in part, mitochondrial adaptations such as training-induced increasing rates of citrate synthase (P = 0.06), β-hydroxyacyl CoA dehydrogenase activity (P < 0.05), cytochrome c oxidase IV (P < 0.05) and a fatty acid transporter, fatty acid translocase/CD36 (P < 0.05), proteins after exercise training. These results suggest that lactate accumulation during high-intensity interval exercise may be associated with mitochondrial adaptations after chronic exercise training.
研究論文（学術雑誌）, 英語

Daily heat stress treatment rescues denervation-activated mitochondrial clearance and atrophy in skeletal muscle
Yuki Tamura; Yu Kitaoka; Yutaka Matsunaga; Daisuke Hoshino; Hideo Hatta
JOURNAL OF PHYSIOLOGY-LONDON, WILEY-BLACKWELL, 593巻, 12号, 掲載ページ 2707-2720, 出版日 2015年06月, 査読付, Traumatic nerve injury or nerve disease leads to denervation and severe muscle atrophy. Recent evidence shows that mitochondrial loss could be a key mediator of skeletal muscle atrophy. Here, we show that daily heat stress treatment rescues denervation-induced loss of mitochondria and concomitant muscle atrophy. We also found that denervation-activated autophagy-dependent mitochondrial clearance (mitophagy) was suppressed by daily heat stress treatment. The molecular basis of this observation is explained by our results showing that heat stress treatment attenuates the increase of key proteins that regulate the tagging step for mitochondrial clearance and the intermediate step of autophagosome formation in denervated muscle. These findings contribute to the better understanding of mitochondrial quality control in denervated muscle from a translational perspective and provide a mechanism behind the attenuation of muscle wasting by heat stress.
Traumatic nerve injury or motor neuron disease leads to denervation and severe muscle atrophy. Recent evidence indicates that loss of mitochondria and the related reduction in oxidative capacity could be key mediators of skeletal muscle atrophy. As our previous study showed that heat stress increased the numbers of mitochondria in skeletal muscle, we evaluated whether heat stress treatment could have a beneficial impact on denervation-induced loss of mitochondria and subsequent muscle atrophy. Here, we report that daily heat stress treatment (mice placed in a chamber with a hot environment; 40 degrees C, 30minday(-1), for 7days) rescues the following parameters: (i)muscle atrophy (decreased gastrocnemius muscle mass); (ii)loss of mitochondrial content (decreased levels of ubiquinol-cytochrome c reductase core proteinII, cytochrome c oxidase subunitsI and IV and voltage-dependent anion channel protein); and (iii)reduction in oxidative capacity (reduced maximal activities of citrate synthase and 3-hydroxyacyl-CoA dehydrogenase) in denervated muscle (produced by unilateral sciatic nerve transection). In order to gain a better understanding of the above mitochondrial adaptations, we also examined the effects of heat stress on autophagy-dependent mitochondrial clearance (mitophagy). Daily heat stress normalized denervation-activated induction of mitophagy (increased mitochondrial microtubule-associated protein 1A/1B-light chain3-II (LC3-II) with and without blocker of autophagosome clearance). The molecular basis of this observation was explained by the results that heat stress attenuated the denervation-induced increase in key proteins that regulate the following steps: (i)the tagging step of mitochondrial clearance (increased mitochondrial Parkin, ubiquitin-conjugated, P62/sequestosome 1 (P62/SQSTM1)); and (ii)the elongation step of autophagosome formation (increased Atg5-Atg12 conjugate and Atg16L). Overall, our results contribute to the better understanding of mitochondrial quality control and the mechanisms behind the attenuation of muscle wasting by heat stress in denervated skeletal muscle.
研究論文（学術雑誌）, 英語

Pre-exercise casein peptide supplementation enhances endurance training-induced mitochondrial enzyme activity in slow twitch muscle, but not fast twitch muscle of high fat diet-fed mice
Matsunaga Yutaka; Tamura Yuki; Takahashi Yumiko; Masuda Hiroyuki; Hoshino Daisuke; Kitaoka Yu; Saito Noriko; Nakamura Hirohiko; Takeda Yasuhiro; Hatta Hideo
The Journal of Physical Fitness and Sports Medicine, The Japanese Society of Physical Fitness and Sports Medicine, 4巻, 5号, 掲載ページ 377-384, 出版日 2015年, 査読付

Chronic Post-Exercise Lactate Administration with Endurance Training Increases Glycogen Concentration and Monocarboxylate Transporter 1 Protein in Mouse White Muscle
Daisuke Hoshino; Tatsuya Hanawa; Yumiko Takahashi; Hiroyuki Masuda; Mai Kato; Hideo Hatta
JOURNAL OF NUTRITIONAL SCIENCE AND VITAMINOLOGY, CENTER ACADEMIC PUBL JAPAN, 60巻, 6号, 掲載ページ 413-419, 出版日 2014年12月, 査読付, Lactate is oxidized as an energy fuel during exercise, and it also plays a key role in the regulation of glycogen synthesis in the muscles and liver after exercise. Previous studies have suggested that lactate is converted to glycogen and stimulates glycogen synthesis. However, it remains unclear whether chronic post-exercise lactate administration can increase glycogen storage in skeletal muscle. We examined whether 3 wk of chronic post-exercise lactate administration with training can increase muscle glycogen storage and whether such changes are associated with monocarboxylate transporter 1 (MCT1) protein expression in mice. Mice were assigned to receive saline with training (SA+T group; n=6) or lactate with training (LA+T group; n=6). All mice performed 40 min of treadmill running at 25 m/min, following which they received saline or lactate (2.5 mg/g body weight), 6 d/wk for 3 wk. After 3 wk, glycogen concentration at rest was higher in the white tibialis anterior (TA; p<0.05, +34%), but not in the red TA, in the LA+T group. Protein expression of MCT1, the primary lactate transporter, was increased with chronic post-exercise lactate administration in the white TA (p<0.05, +32%), but not in the red TA. MCT1 protein expression was significantly correlated with muscle glycogen concentration in the red and white TA in both groups (p<0.05, r=0.9.69). These results suggest that chronic lactate administration after exercise increases MCT1 protein expression, which can be involved in the regulation of the observed increase in muscle glycogen storage after exercise training.
研究論文（学術雑誌）, 英語

Postexercise whole body heat stress additively enhances endurance training-induced mitochondrial adaptations in mouse skeletal muscle
Yuki Tamura; Yutaka Matsunaga; Hiroyuki Masuda; Yumiko Takahashi; Yuki Takahashi; Shin Terada; Daisuke Hoshino; Hideo Hatta
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, AMER PHYSIOLOGICAL SOC, 307巻, 7号, 掲載ページ R931-R943, 出版日 2014年10月, 査読付, A recent study demonstrated that heat stress induces mitochondrial biogenesis in C2C12 myotubes, thereby implying that heat stress may be an effective treatment to enhance endurance training-induced mitochondrial adaptations in skeletal muscle. However, whether heat stress actually induces mitochondrial adaptations in skeletal muscle in vivo is unclear. In the present study, we report the novel findings that 1) whole body heat stress produced by exposure of ICR mice to a hot environment (40(circle)C, 30 min/day, 5 days/wk, 3 wk) induced mitochondrial adaptations such as increased mitochondrial enzyme activity (citrate synthase and 3-hydroxyacyl CoA dehydrogenase) and respiratory chain protein content (complexes I-V) in skeletal muscle in vivo and 2) postexercise whole body heat stress additively enhanced endurance training-induced mitochondrial adaptations (treadmill running, 25 m/min, 30 min/day, 5 days/wk, 3 wk). Moreover, to determine the candidate mechanisms underlying mitochondrial adaptations, we investigated the acute effects of postexercise whole body heat stress on the phosphorylation status of cellular signaling cascades that subsequently induce mitochondrial gene transcription. We found that whole body heat stress boosted the endurance exercise-induced phosphorylation of p38 MAPK, increased the phosphorylation status of p70S6K, a biomarker of mammalian target of rapamycin complex 1 activity, and unexpectedly dephosphorylated AMP-activated protein kinase and its downstream target acetyl-CoA carboxylase in skeletal muscle. Our present observations suggest that heat stress can act as an effective postexercise treatment. Heat stress treatment appeared to be clinically beneficial for people who have difficulty participating in sufficient exercise training, such as the elderly, injured athletes, and patients.
研究論文（学術雑誌）, 英語

High-intensity interval training increases intrinsic rates of mitochondrial fatty acid oxidation in rat red and white skeletal muscle
Daisuke Hoshino; Yuko Yoshida; Yu Kitaoka; Hideo Hatta; Arend Bonen
Applied Physiology, Nutrition and Metabolism, 3, 38巻, 3号, 掲載ページ 326-333, 出版日 2013年, 査読付, High-intensity interval training (HIIT) can increase mitochondrial volume in skeletal muscle. However, it is unclear whether HIIT alters the intrinsic capacity of mitochondrial fatty acid oxidation, or whether such changes are associated with changes in mitochondrial FAT/CD36, a regulator of fatty acid oxidation, or with reciprocal changes in the nuclear receptor coactivator (peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1α)) and the corepressor (receptorinteracting protein 140 (RIP140)). We examined whether HIIT alters fatty acid oxidation rates in the isolated subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria of red and white skeletal muscle and (or) induces changes in muscle PGC-1α and RIP140 proteins and mitochondrial FAT/CD36 protein content. Rats were divided into untrained or HIIT-trained groups. HIIT animals performed 10 bouts of 1-min high-intensity treadmill running (30-55 m·min-1), separated by 2 min of rest, for 5 days a week for 4 weeks. As expected, after the training period, HIIT increased mitochondrial enzymes (citrate synthase, COXIV, and β-hydroxyacyl CoA dehydrogenase) in red and white muscle, indicating that muscle mitochondrial volume had increased. HIIT also increased the rates of palmitate oxidation in mitochondria of red (37% for SS and 19% for IMF) and white (36% for SS and 12% for IMF) muscle. No changes occurred in SS and IMF mitochondrial FAT/CD36 proteins, despite increasing FAT/CD36 at the whole-muscle level (27% for red and 22% for white). Concurrently, muscle PGC-1α protein was increased in red (22%) and white (16%) muscle, but RIP140 was not altered. These results indicate that increases in SS and IMF mitochondrial fatty acid oxidation induced by HIIT are accompanied by an increase in PGC-1α, but not RIP140 or FAT/CD36.
研究論文（学術雑誌）, 英語

Monocarboxylate transporter and lactate metabolism
Kitaoka Yu; Hoshino Daisuke; Hatta Hideo
The journal of physical fitness and sports medicine : JPFSM, The Japanese Society of Physical Fitness and Sports Medicine, 1巻, 2号, 掲載ページ 247-252, 出版日 2012年07月, For many years, lactate was considered as a metabolic waste product, and a cause of fatigue during exercise. However, lactate is now known as a carbohydrate fuel source, shuttled between cells and tissues. The movement of lactate across the plasma membrane is facilitated by a family of monocarboxylate transporters (MCTs). Among 14 identified MCT isoforms, MCT1 and MCT4 are present in the plasma membranes of skeletal muscle and are suggested to be related to exercise performance. Reports have shown that exercise training increases both MCT1 and MCT4 in skeletal muscle. This review will discuss the role of lactate as a fuel and exercise training-induced changes in lactate metabolism. In addition, studies of Thoroughbred horses, as models of elite athletes, are introduced.
英語

Clenbuterol, a β2-adrenergic agonist, reciprocally alters PGC-1 alpha and RIP140 and reduces fatty acid and pyruvate oxidation in rat skeletal muscle.
Hoshino D; Yoshida Y; Holloway GP; Lally J; Hatta H; Bonen A
American journal of physiology. Regulatory, integrative and comparative physiology, AMER PHYSIOLOGICAL SOC, 302巻, 3号, 掲載ページ R373-R384, 出版日 2012年02月, 査読付, Hoshino D, Yoshida Y, Holloway GP, Lally J, Hatta H, Bonen A. Clenbuterol, a beta 2-adrenergic agonist, reciprocally alters PGC-1 alpha and RIP140 and reduces fatty acid and pyruvate oxidation in rat skeletal muscle. Am J Physiol Regul Integr Comp Physiol 302: R373-R384, 2012. First published November 9, 2011; doi:10.1152/ajpregu.00183.2011.-Clenbuterol, a beta 2-adrenergic agonist, reduces mitochondrial content and enzyme activities in skeletal muscle, but the mechanism involved has yet to be identified. We examined whether clenbuterol-induced changes in the muscles' metabolic profile and the intrinsic capacity of mitochondria to oxidize substrates are associated with reductions in the nuclear receptor coactivator PGC-1 alpha and/or an increase in the nuclear corepressor RIP140. In rats, clenbuterol was provided in the drinking water (30 mg/l). In 3 wk, this increased body (8%) and muscle weights (12-17%). In red (R) and white (W) muscles, clenbuterol induced reductions in mitochondrial content (citrate synthase: R, 27%; W, 52%; cytochrome-c oxidase: R, 24%; W, 34%), proteins involved in fatty acid transport (fatty acid translocase/CD36: R, 36%; W, 35%) and oxidation [beta-hydroxyacyl CoA dehydrogenase (beta-HAD): R, 33%; W, 62%], glucose transport (GLUT4: R, 8%; W, 13%), lactate transport monocarboxylate transporter (MCT1: R, 61%; W, 37%), and pyruvate oxidation (PDHE1 alpha, R, 18%; W, 12%). Concurrently, only red muscle lactate dehydrogenase activity (25%) and MCT4 (31%) were increased. Palmitate oxidation was reduced in subsarcolemmal (SS) (R, 30%; W, 52%) and intermyofibrillar (IMF) mitochondria (R, 17%; W, 44%) along with reductions in beta-HAD activity (SS: R, 17%; W, 51%; IMF: R, 20%; W, 57%). Pyruvate oxidation was only reduced in SS mitochondria (R, 20%; W, 28%), but this was not attributable solely to PDHE1 alpha, which was reduced in both SS (R, 21%; W, 20%) and IMF mitochondria (R, 15%; W, 43%). These extensive metabolic changes induced by clenbuterol were associated with reductions in PGC-1 alpha (R, 37%; W, 32%) and increases in RIP140 (R, 23%; W, 21%). This is the first evidence that clenbuterol appears to exert its metabolic effects via simultaneous and reciprocal changes in the nuclear receptor coactivator PGC-1 alpha and the nuclear corepressor RIP140.
研究論文（学術雑誌）, 英語

Effect of growth on monocarboxylate transporters and indicators of energy metabolism in the gluteus medius muscle of Thoroughbreds
Yu Kitaoka; Daisuke Hoshino; Kazutaka Mukai; Atsushi Hiraga; Tohru Takemasa; Hideo Hatta
AMERICAN JOURNAL OF VETERINARY RESEARCH, AMER VETERINARY MEDICAL ASSOC, 72巻, 8号, 掲載ページ 1107-1111, 出版日 2011年08月, 査読付, Objective-To examine the changes in monocarboxylate transporter (MCT) 1 and MCT4 content and in indicators of energy metabolism in the gluteus medius muscle (GMM) of Thoroughbreds during growth.
Animals-6 Thoroughbreds (3 males and 3 females).
Procedures-Samples of GMM were obtained when horses were 2, 6, 12, and 24 months old. Muscle proteins were separated via SDS-PAGE; amounts of MCT1 and MCT4 and peroxisome proliferator-activated receptor-gamma coactivator-1 alpha content were determined by use of western blotting. Muscle activities of phosphofructokinase and citrate synthase were measured biochemically; lactate dehydrogenase isoenzymes were separated by agarose gel electrophoresis and quantified.
Results-Compared with findings when horses were 2 months old, MCT1 protein content in GMM samples obtained when the horses were 24 months old was significantly higher; however, MCT4 protein content remained unchanged throughout the study period. Peroxisome proliferator-activated receptor-alpha coactivator-1 alpha content was significantly increased at 24 months of age and citrate synthase activity was increased at 6 and 24 months of age, compared with findings at 2 months. Phosphofructokinase activity remained unaltered during growth. The percentage contributions of lactate dehydrogenase 1 and 2 isoenzymes to the total amount of all 5 isoenzymes at 12 and 24 months of age were significantly higher than those at 2 months of age.
Conclusions and Clinical Relevance-Changes in protein contents of MCTs and the lactate dehydrogenase isoenzyme profile in GMM samples suggested that lactate usage capacity increases with growth and is accompanied by an increase in the oxidative capacity in Thoroughbreds. (Am J Vet Res 2011;72:1107-1111)
研究論文（学術雑誌）, 英語

Higher Lactate Transporter Protein and Citrate Synthase Activity Following Short-term High-intensity Repetition Training in Mice
Hoshino Daisuke; Matsumae Haruka; Kato Mai; Hatta Hideo
International Journal of Sport and Health Science, Japan Society of Physical Education, Health and Sport Sciences, 8巻, 掲載ページ 43-49, 出版日 2010年, 査読付, The purpose of this study was to examine the effects of high-intensity repetition training, consisting of 4 bouts of high-intensity exercise with long rest periods, on lactate metabolism. To achieve this goal, we compared effects of 3 weeks of two different exercise regimes: high-intensity repetition training (4×1 min run at 45-53 m/min with 19 min of recovery=total 36 running bouts of 1 min), and voluntary wheel running activity, which mimics endurance training. To evaluate the effects on lactate metabolism, we measured protein levels of the monocarboxylate transporters (MCT). We also measured citrate synthase activity as a marker of oxidative capacity in working muscle. After 3 weeks of training, repetition training, but not wheel running training, increased the levels of MCT1 protein, which contributes to lactate uptake into skeletal muscle, in soleus (p<0.05) and also muscular citrate synthase activity in tibialis anterior (p<0.05). MCT4 protein, which plays the role in the removal of lactate from muscle, did not change in plantaris or tibialis anterior following either training regime. These data suggest that short-term high-intensity repetition training is effective at increasing MCT1 and mitochondrial oxidative capacity in skeletal muscle compared to running wheel activity.

英語

Effects of high-intensity training on monocarboxylate transporters in Thoroughbred horses
Yu Kitaoka; Yuki Wakasugi; Daisuke Hoshino; Kazutaka Mukai; Atsushi Hiraga; Hideo Hatta
Comparative Exercise Physiology, 6巻, 4号, 掲載ページ 171-175, 出版日 2009年, 査読付, The aim of this study was to investigate the effect of high-intensity training on lactate transporters (monocarboxylate transporters (MCTs)) in Thoroughbred horses. Five Thoroughbreds (three males and two geldings
3–10 years old
478 ± 13 kg) ran at 100% maximal oxygen uptake (VO2max) for 1 min (3 days per week, 3 weeks) or 2 min (2 days per week, 4 weeks) on a treadmill for 7 weeks. VO2max and ability to sustain an incremental all-out test of maximal running were measured, and muscle samples were obtained from the gluteus medius muscle at rest before and after the training. The performance in the all-out test and VO2max were increased after the training. The protein content of MCT1 and MCT4 in the gluteus medius muscles was not significantly altered. However, MCT1 showed a relationship with the duration of maximal exercise after the training. The changes in MCT4 showed a relationship with the increase in exercise duration by the training. These results suggest that in Thoroughbreds, although the overall changes in MCT protein after endurance training are small, MCT1 and MCT4 can play important roles in the capacity to sustain maximal exercise. © 2010, Cambridge University Press. All rights reserved.
研究論文（学術雑誌）, 英語

Single-cell information analysis reveals small intra- and large intercellular variations increase cellular information capacity
Wada T; Wataya M; Fujii M; Hironaka K; Eto M; Uda S; Hoshino D; Kunida K; Inoue H; Kubota H; Hamaguchi H; Furuichi Y; Manabe Y; Fujii N; Kuroda S
出版日 2019年05月, bioRxiv

B-1-3 Heat stress treatment rescues denervation-induced mitochondrial loss in skeletal muscle(The Proceedings of the 23rd Annual Meetings of Japan Society of Exercise and Sports Physiology July 25・26, (Tokyo)) :
Tamura Yuki; Kitaoka Yu; Matsunaga Yutaka; Hoshino Daisuke; Hatta Hideo
Japan Society of Exercise and Sports Physiology, 出版日 2015年, Advances in exercise and sports physiology, 21巻, 4号, 掲載ページ 77-77, 英語, 1340-3141, 110010015279, AA11107566

High-intensity interval training increases the rate of mitochondrial fatty acid oxidation in rat skeletal muscle
HOSHINO Daisuke; YOSHIDA Yuko; HATTA Hideo
出版日 2012年02月01日, 体力科學, 61巻, 1号, 掲載ページ 55-55, 英語, 0039-906X, 10030139788, AN00137986

カゼインペプチドの長期摂取がエネルギー代謝に及ぼす影響
松永裕; 田村優樹; 増田紘之; 高橋祐美子; 星野太佑; 八田秀雄
出版日 2012年, 体力科学, 61巻, 6号, 0039-906X, 201302250175802178

2-A-09 Single oral taurine supplementation activates muscleglycogen resynthesis during period of recovery from exhaustive exercise(The Proceedings of the 19th Annual Meetings of Japan Society of Exercise and Sports Physiology August 25・26, (Tokushima)) :
Takahashi Yumiko; Hoshino Daisuke; Hatta Hideo
Japan Society of Exercise and Sports Physiology, 出版日 2011年, Advances in exercise and sports physiology, 17巻, 2号, 掲載ページ 54-54, 英語, 1340-3141, 110009437974, AA11107566

2-A-08 Changes in protein contents of PGC-1α and RIP140 and metabolic adaptation after three weeks of clenbuterol administration(The Proceedings of the 19th Annual Meetings of Japan Society of Exercise and Sports Physiology August 25・26, (Tokushima)) :
HOSHINO Daisuke; HATTA Hideo
Japan Society of Exercise and Sports Physiology, 出版日 2011年, Advances in exercise and sports physiology, 17巻, 2号, 掲載ページ 54-54, 英語, 1340-3141, 110009437973, AA11107566

265. サラブレッドにおける発育発達によるMCTタンパク質量の変化(代謝,一般口演,第63回日本体力医学会大会)
北岡 祐; 星野 太佑; 向井 和隆; 平賀 敦; 八田 秀雄
日本体力医学会, 出版日 2008年12月01日, 体力科學, 57巻, 6号, 0039-906X, 110007164556

273. ビタミンB1誘導体の投与が、安静時及び持久的運動時における糖代謝に与える影響(代謝,一般口演,第63回日本体力医学会大会)
増田 紘之; 増田 毅; 星野 太佑; 北岡 祐; 加藤 麻衣; 八田 秀雄
日本体力医学会, 出版日 2008年12月01日, 体力科學, 57巻, 6号, 掲載ページ 769-769, 日本語, 0039-906X, 110007164789, AN00137986

244. 高強度のレペティショントレーニングは糖の利用を増加させる(代謝,一般口演,第63回日本体力医学会大会)
星野 太佑; 加藤 麻衣; 増田 紘之; 北岡 祐; 八田 秀雄
日本体力医学会, 出版日 2008年12月01日, 体力科學, 57巻, 6号, 0039-906X, 110007165072

194. 3週間の高強度トレーニングがマウスの乳酸代謝に与える影響(代謝,第62回日本体力医学会大会)
星野 太佑; 松前 遥; 加藤 麻衣; 増田 紘之; 八田 秀雄
日本体力医学会, 出版日 2007年12月01日, 体力科學, 56巻, 6号, 掲載ページ 675-675, 日本語, 0039-906X, 110006652488, AN00137986

206. 乳酸の長期投与が運動中の乳酸を中心とする糖代謝に及ぼす影響(代謝,第62回日本体力医学会大会)
加藤 麻衣; 星野 太佑; 松前 遥; 増田 紘之; 八田 秀雄
日本体力医学会, 出版日 2007年12月01日, 体力科學, 56巻, 6号, 0039-906X, 110006652500

207. フルスルチアミン投与が持久的運動における乳酸を中心とする糖代謝に与える影響(代謝,第62回日本体力医学会大会)
増田 紘之; 松前 遥; 星野 太佑; 加藤 麻衣; 八田 秀雄
日本体力医学会, 出版日 2007年12月01日, 体力科學, 56巻, 6号, 掲載ページ 682-682, 日本語, 0039-906X, 110006652501, AN00137986

208. サラブレッドの各組織におけるMCTタンパク質の分布(代謝,第62回日本体力医学会大会)
北岡 祐; 星野 太佑; 向井 和隆; 平賀 敦; 八田 秀雄
日本体力医学会, 出版日 2007年12月01日, 体力科學, 56巻, 6号, 0039-906X, 110006652502

3. Effect of one week of high intensity training on lactate metabolism in mice(The Proceedings of the 15th Annual Meetings of Japan Society of Exercise and Sports Physiology July 26-27, (Hirosaki)) :
HOSHINO Daisuke; MATSUMAE Haruka; HATTA Hideo
Japan Society of Exercise and Sports Physiology, 出版日 2007年, Advances in exercise and sports physiology, 13巻, 3号, 掲載ページ 56-56, 英語, 1340-3141, 110006570705, AA11107566

6. Effect of TTFD administration on glucose and lactate metabolism in mice during high intensity exercise(The Proceedings of the 15th Annual Meetings of Japan Society of Exercise and Sports Physiology July 26-27, (Hirosaki)) :
MATSUMAE Haruka; HOSHINO Daisuke; HATTA Hideo
Japan Society of Exercise and Sports Physiology, 出版日 2007年, Advances in exercise and sports physiology, 13巻, 3号, 掲載ページ 57-57, 英語, 1340-3141, 110006570708, AA11107566

乳酸が骨格筋の適応を引き起こす新たな基盤創出とその応用
八田 秀雄; 北岡 祐; 高橋 謙也; 星野 太佑
日本学術振興会, 科学研究費助成事業, 東京大学, 基盤研究(B), 24K02812
研究期間 2024年04月01日 - 2028年03月31日

乳酸による適応のメカニズム解明とその応用
八田 秀雄; 北岡 祐; 星野 太佑
日本学術振興会, 科学研究費助成事業 基盤研究(B), 東京大学, 基盤研究(B), 昨年度、運動時の乳酸産生量を血中乳酸濃度から算出する方法を確立し、持久的トレーニングを実施したマウスに適用したところ、乳酸産生量として妥当な結果が得られた。そこで、今年度は運動時の血中乳酸濃度が低いことが明らかになっているperoxisome proliferator-activated receptor γ coactivator-1 (PGC-1)αの過剰発現マウスにおいて運動中の乳酸産生量を算出し、持久的トレーニングと比較・検討した。まず、PGC-1α過剰発現マウスの全身の乳酸取り込み能力は、野生型マウスと比較して有意に高いことがわかった。次に、絶対的な運動強度 (トレッドミルの速度)をあわせた運動中の乳酸産生量を算出したところ、PGC-1α過剰発現マウスの乳酸産生量は、野生型マウスと比較して有意に低値を示した。血中乳酸濃度が同等になるように相対的に運動強度を合わせた場合、PGC-1α過剰発現は乳酸産生量を増加させた。この結果は、全身の乳酸取り込み能力の高い動物が、コントロールの動物と同じ血中乳酸濃度を達成するためには、運動中より多くの乳酸産生量が必要であることを示唆している。また、重回帰分析により、持久的トレーニングを実施したマウスにおける乳酸産生量は、PFKとMCT4により正に、MCT1とミトコンドリア量により負に貢献していたが、PGC-1α過剰発現マウスにおける乳酸産生量には、そのような関係はみられなかった。このことから、PGC-1α過剰発現による乳酸産生量の抑制は、それらのタンパク質以外の影響が大きい可能性が示唆された。, 20H04071
研究期間 2020年04月01日 - 2024年03月31日

持久的運動効果の減弱化のメカニズム解明とその解決策
星野 太佑
日本学術振興会, 科学研究費助成事業 基盤研究(C), 電気通信大学, 基盤研究(C), 昨年度，冷却はミトコンドリア生合成のマスターレギュレーターであるperoxisome proliferator-activated receptor γ coactivator-1 (PGC-1)αのmRNA発現量の筋収縮後の増加を減弱させることを明らかにした．今年度はその分子メカニズムについて，シグナル分子のリン酸化に着目し検証した． Wistar系雄性ラットを常温群と冷却群にわけ，常温群は水, 冷却群は氷水の入った袋を用いて，下腿前部を3分間冷却した. その後, 前脛骨筋を20 Hzにて1秒間電気刺激, 1秒間休息を30回繰り返すプロトコルを1セットとし, これを10セット実施した. 筋収縮直後に両脚の前脛骨筋を摘出し，AMP-activatedprotein kinase (AMPK) calcium/calmodulin-dependent protein kinase II (CaMKII)，p38 mitogen-activated protein kinase (p38 MAPK)のリン酸化をウエスタンブロッティングを用いて，測定した．また，筋グリコーゲン濃度と筋中乳酸濃度を生化学的に測定した．その結果，両群のAMPK，CaMKII，p38 MAPKのリン酸化は，筋収縮によって有意に増加した．さらに，冷却は，AMPKのリン酸化の増加を有意に減弱させた．しかし，CaMKII，p38 MAPKのリン酸化には，冷却の影響は見られなかった．また，筋グリコーゲン濃度の筋収縮による減少は，冷却により有意に抑制された． 以上の結果から，冷却は，筋収縮によるAMPKの活性化および筋グリコーゲン分解を減弱させ，PGC-1αのmRNA発現量の増加を抑制する可能性が示唆された．, 20K11417
研究期間 2020年04月01日 - 2023年03月31日

ドーピング禁止薬物の投与による代謝的適応にエピジェネティクスな制御は関わるか
星野 太佑
日本学術振興会, 科学研究費助成事業 若手研究, 電気通信大学, 若手研究, 本研究では，筋肥大を引き起こすクレンブテロール摂取およびレジスタンストレーニングが骨格筋と脂肪組織に代謝的適応に与える影響を検証した．クレンブテロール摂取は，骨格筋のミトコンドリアの融合・分裂に関わるタンパク質の発現量の減少させ，ミトコンドリアの異常な形態変化を誘導した．そのような変化が起きる時，ヒストン脱アセチル化酵素4 (HDAC4)の核移行に変化はなかった．4週間のレジスタンストレーニングは，皮下白色脂肪細胞の大きさを減少させ，褐色脂肪細胞のミトコンドリアの酵素のタンパク質量を増加させることを明らかにした．以上のような現象のメカニズムについて今後さらに検証する必要がある．, 18K17792
研究期間 2018年04月01日 - 2020年03月31日

乳酸による骨格筋ミトコンドリア新生のメカニズムの解明
星野 太佑
文部科学省, 科学研究費補助金(若手研究(B)), 東京大学, 若手研究(B), 研究代表者, 本研究では、乳酸が骨格筋ミトコンドリア増殖を引き起こすのか、摘出筋を用いた実験系とC2C12筋管細胞の電気刺激の系で検証した。その結果、摘出筋に対する10mM乳酸刺激は、ミトコンドリアの新生を抑制した。しかし、この時乳酸添加24時間後では、培地中の乳酸濃度が25mMを超えており、非生理学的な高い乳酸濃度であった。電気刺激による乳酸濃度の増加は、C2C12筋管細胞のPGC-1alphaのmRNA量を増加させた。以上の結果から、筋収縮に伴うような乳酸濃度の増加は、転写制御を介してミトコンドリアの新生を引き起こす可能性を示唆した。今後、乳酸濃度の濃度応答性の違いをさらに検証する必要がある。, 25750331
研究期間 2013年 - 2015年

骨格筋の適応を引き起こす筋収縮の時間と強度の最適パターンの解明
星野太佑
文部科学省, 特別研究員奨励費, 研究代表者
研究期間 2014年04月

運動における小脳の乳酸輸送単体monocarboxylate transporter2(MCT2)の役割の解明
星野太佑
日本科学協会, 笹川科学研究助成, 研究代表者
研究期間 2013年04月 - 2014年03月

乳酸がミトコンドリア増殖のシグナルとなる可能性の検討
星野 太佑
文部科学省, 科学研究費補助金(研究活動スタート支援, 研究活動スタート支援), 東京大学, 研究活動スタート支援, 研究活動スタート支援, 研究代表者, 本研究では、乳酸が運動による骨格筋ミトコンドリア増殖のシグナル因子となるのか明らかにすることを目的とし、研究を行った。まず、マウスへの運動前のジクロロ酢酸摂取が、運動中の体内の乳酸濃度を低下させることを確認した。そのDCA摂取を用いて、マウスに乳酸濃度の低い運動を継続して行うトレーニングを4週間行わせた結果、同じ強度でも乳酸濃度の低い運動トレーニングを行った群では、通常のトレーニングによって引き起こされるミトコンドリアの増加が抑制されることが明らかとなった。このことは、乳酸がミトコンドリア増殖のシグナル因子になりうる可能性を示唆するものである。, 23800021
研究期間 2011年 - 2012年