Temporal changes in ERK phosphorylation are harmonious with 4E-BP1, but not p70S6K, during clenbuterol-induced hypertrophy in the rat gastrocnemius

Sumi, Koichiro; Higashi, Seiichiro; Natsume, Mitsutaka; Kawahata, Keiko; Nakazato, Koichi

doi:10.1139/apnm-2013-0431

Cited by 4 publications

(2 citation statements)

References 53 publications

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“…However, relatively high concentrations (20 and 50 μM) could only block the translation of other tight junction related proteins, such as occludin or claudin-1, but not ZO-1 (data not shown), suggesting that ZO-1 is a fairly stable protein. In another experiment, inactive forms of the translation repressor 4E-BP1 were examined, as it was reported to be under the control of MAPK/ERK [ 32 , 33 , 34 , 35 ]. Deactivation of 4E-BP1 occurs by phosphorylation at two critical positions: Thr70 and Ser65 [ 36 , 37 , 38 ].…”

Section: Discussionmentioning

confidence: 99%

The Role of Processed Aloe vera Gel in Intestinal Tight Junction: An In Vivo and In Vitro Study

Phan

Park

Jung

et al. 2021

IJMS

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Leaky gut is a condition of increased paracellular permeability of the intestine due to compromised tight junction barriers. In recent years, this affliction has drawn the attention of scientists from different fields, as a myriad of studies prosecuted it to be the silent culprit of various immune diseases. Due to various controversies surrounding its culpability in the clinic, approaches to leaky gut are restricted in maintaining a healthy lifestyle, avoiding irritating factors, and practicing alternative medicine, including the consumption of supplements. In the current study, we investigate the tight junction-modulating effects of processed Aloe vera gel (PAG), comprising 5–400-kD polysaccharides as the main components. Our results show that oral treatment of 143 mg/kg PAG daily for 10 days improves the age-related leaky gut condition in old mice, by reducing their individual urinal lactulose/mannitol (L/M) ratio. In concordance with in vivo experiments, PAG treatment at dose 400 μg/mL accelerated the polarization process of Caco-2 monolayers. The underlying mechanism was attributed to enhancement in the expression of intestinal tight junction-associated scaffold protein zonula occludens (ZO)-1 at the translation level. This was induced by activation of the MAPK/ERK signaling pathway, which inhibits the translation repressor 4E-BP1. In conclusion, we propose that consuming PAG as a complementary food has the potential to benefit high-risk patients.

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Section: Discussionmentioning

confidence: 99%

The Role of Processed Aloe vera Gel in Intestinal Tight Junction: An In Vivo and In Vitro Study

Phan

Park

Jung

et al. 2021

IJMS

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“…Evoked torque was monitored using a custom-made electrical stimulation and joint movement-controlling device that was described previously (Sumi, Higashi, Natsume, Kawahata, & Nakazato, 2014).…”

Section: Forced Resistance Exercise In Vivomentioning

confidence: 99%

Repeated stretch–shortening contraction of the triceps surae attenuates muscle atrophy and liver dysfunction in a rat model of inflammation

Sumi

Ashida

Nakazato

2020

Experimental Physiology

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Stretch-shortening contraction (SSC) is an effective modality to improve skeletal muscle mass.However, the beneficial effects of SSC in the presence of chronic inflammation remain unclear.Here, we imposed five SSC sessions unilaterally on the triceps surae in young female Lewis rats. Rats were injected with vehicle or peptidoglycan-polysaccharide (PG-PS) to induce longlasting inflammation. The PG-PS reduced gastrocnemius muscle mass in both legs, but that of the SSC-trained leg was significantly greater than that of the contralateral leg. Circulating proinflammatory cytokines, such as IL-1 , were significantly increased by PG-PS injection, even if carrying out SSC. The circulating anti-inflammatory cytokine IL-10 increased with SSC in both healthy and inflammatory conditions. Stretch-shortening contraction also prevented increases in serum aspartate aminotransferase activity and plasma free phenylalanine concentration induced by PG-PS, in comparison to the control resistance exercise consisting of isometric contractions. Moreover, aspartate aminotransferase and phenylalanine concentrations demonstrated a

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Resistance exercise with anti-inflammatory foods attenuates skeletal muscle atrophy induced by chronic inflammation

Sumi

Ashida

Nakazato

2020

Journal of Applied Physiology

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Chronic inflammation (CI) can contribute to muscle atrophy and sarcopenia. Resistance exercise (RE) promotes increased and/or maintenance of skeletal muscle mass, but the effects of RE in the presence of CI are unclear. In this study, we developed a novel animal model of CI-induced muscle atrophy and examined the effect of acute or chronic RE by electrical stimulation. CI was induced in young female Lewis rats by injection with peptidoglycan-polysaccharide (PG-PS). Extracellular signal-regulated kinase (ERK), p70S6 kinase (p70S6K), 4E binding protein 1 (4E-BP1), Akt, and Forkhead box O1 (FOXO1) phosphorylation levels increased in gastrocnemius (Gas) muscle from normal rats subjected to acute RE. After acute RE in CI rats, increased levels of phosphorylated ERK, p70S6K, and 4E-BP1, but not Akt or FOXO1, were observed. Chronic RE significantly increased the Gas weight in the exercised limb relative to the nontrained opposing limb in CI rats. Dietary supplementation with anti-inflammatory agents, eicosapentaenoic/docosahexaenoic acid and α-lactalbumin attenuated CI-induced muscle atrophy in the untrained Gas and could promote RE-induced inhibition of atrophy in the trained Gas. In the trained leg, significant negative correlations ( r ≤ −0.80) were seen between Gas weights and CI indices, including proinflammatory cytokines and white blood cell count. These results indicated that the anabolic effects of RE are effective for preventing CI-induced muscle atrophy but are partially attenuated by inflammatory molecules. The findings also suggested that anti-inflammatory treatment together with RE is an effective intervention for muscle atrophy induced by CI. Taken together, we conclude that systemic inflammation levels are associated with skeletal muscle protein metabolism and plasticity. NEW & NOTEWORTHY This study developed a novel chronic inflammation (CI) model rat demonstrating that resistance exercise (RE) induced activation of protein synthesis signaling pathways and mitigated skeletal muscle atrophy. These anabolic effects were partially abrogated likely through attenuation of Akt/Forkhead box O1 axis activity. The degree of skeletal muscle atrophy was related to inflammatory responses. Dietary supplementation with anti-inflammatory agents could enhance the anabolic effect of RE. Our findings provide insight for development of countermeasures for CI-related muscle atrophy, especially secondary sarcopenia.

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Temporal changes in ERK phosphorylation are harmonious with 4E-BP1, but not p70S6K, during clenbuterol-induced hypertrophy in the rat gastrocnemius

Cited by 4 publications

References 53 publications

The Role of Processed Aloe vera Gel in Intestinal Tight Junction: An In Vivo and In Vitro Study

The Role of Processed Aloe vera Gel in Intestinal Tight Junction: An In Vivo and In Vitro Study

Repeated stretch–shortening contraction of the triceps surae attenuates muscle atrophy and liver dysfunction in a rat model of inflammation

Resistance exercise with anti-inflammatory foods attenuates skeletal muscle atrophy induced by chronic inflammation

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