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  • Title/Summary/Keyword: Skeletal muscle

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Changes in expression of the autophagy-related genes microtubule-associated protein 1 light chain 3β and autophagy related 7 in skeletal muscle of fattening Japanese Black cattle: a pilot study

  • Nakanishi, Tomonori;Tokunaga, Tadaaki;Ishida, Takafumi;Kobayashi, Ikuo;Katahama, Yuta;Yano, Azusa;Erickson, Laurie;Kawahara, Satoshi
    • Asian-Australasian Journal of Animal Sciences
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    • v.32 no.4
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    • pp.592-598
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    • 2019
  • Objective: Autophagy is a bulk degradation system for intracellular proteins which contributes to skeletal muscle homeostasis, according to previous studies in humans and rodents. However, there is a lack of information on the physiological role of autophagy in the skeletal muscle of meat animals. This study was planned as a pilot study to investigate changes in expression of two major autophagy-related genes, microtubule-associated protein 1 light chain 3β (MAP1LC3B) and autophagy related 7 (ATG7) in fattening beef cattle, and to compare them with skeletal muscle growth. Methods: Six castrated Japanese Black cattle (initial body weight: 503±20kg) were enrolled in this study and fattened for 7 months. Three skeletal muscles, M. longissimus, M. gluteus medius, and M. semimembranosus, were collected by needle biopsy three times during the observation period, and mRNA levels of MAP1LC3B and ATG7 were determined by quantitative reverse-transcription polymerase chain reaction. The expression levels of genes associated with the ubiquitin-proteasome system, another proteolytic mechanism, were also analyzed for comparison with autophagy-related genes. In addition, ultrasonic scanning was repeatedly performed to measure M. longissimus area as an index of muscle growth. Results: Our results showed that both MAP1LC3B and ATG7 expression increased over the observation period in all three skeletal muscles. Interestingly, the increase in expression of these two genes in M. longissimus was highly correlated with ultrasonic M. longissimus area and body weight. On the other hand, the expression of genes associated with the ubiquitin-proteasome system was unchanged during the same period. Conclusion: These findings suggest that autophagy plays an important role in the growth of skeletal muscle of fattening beef cattle and imply that autophagic activity affects meat productivity.

microRNA for determining the age-related myogenic capabilities of skeletal muscle

  • Lee, Kwang-Pyo;Shin, Yeo Jin;Kwon, Ki-Sun
    • BMB Reports
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    • v.48 no.11
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    • pp.595-596
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    • 2015
  • Skeletal muscle exhibits a loss of muscle mass and function with age. Decreased regenerative potential of muscle stem/progenitor cells is a major underlying cause of sarcopenia. We analyzed microRNAs (miRNA) that are differentially expressed in young and old myoblasts, to identify novel intrinsic factors that play a degenerative role in aged skeletal muscle. miR-431, one of decreasing miRNAs in old myoblasts, improved the myogenic differentiation when overexpressed in old myoblast, but suppressed their myogenic capability in knockdowned young myoblasts. We found that miR-431 directly binds to 3` untranslated regions (UTR) of Smad4 mRNA, and decreases its expression. Given that SMAD4 is one of the downstream effectors of TGF-β, a well-known degenerative signaling pathway in myogenesis, the decreased miR-431 in old myoblast causes SMAD4 elevation, thus resulting in defective myogenesis. Exogenous expression of miR-431 greatly improved the muscle regeneration in the cardiotoxin-injured hindlimb muscle of old mice by reducing SMAD4 levels. Since the miR-431 seed sequence is conserved in human SMAD4 3'UTR, miR-431 regulates the myogenic capacity of human skeletal myoblasts in the same manner. Our results suggest that age-associated miR-431 is required for the maintenance of the myogenic capability in myoblasts, thus underscoring its potential as a therapeutic target to slow down muscle aging.

Effects of exercise on AKT/PGC1-α/FOXO3a pathway and muscle atrophy in cisplatin-administered rat skeletal muscle

  • Bae, Jun Hyun;Seo, Dae Yun;Lee, Sang Ho;Shin, Chaeyoung;Jamrasi, Parivash;Han, Jin;Song, Wook
    • The Korean Journal of Physiology and Pharmacology
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    • v.25 no.6
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    • pp.585-592
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    • 2021
  • Cisplatin has been reported to cause side effects such as muscle wasting in humans and rodents. The physiological mechanisms involved in preventing muscle wasting, such as the regulation of AKT, PGC1-α, and autophagy-related factor FOXO3a by MuRF 1 and Atrogin-1, remain unclear following different types of exercise and in various skeletal muscle types. Eight-week-old male Wistar rats (n = 34) were assigned to one of four groups: control (CON, n = 6), cisplatin injection (1 mg/kg) without exercise (CC, n = 8), cisplatin (1 mg/kg) + resistance exercise (CRE, n = 9) group, and cisplatin (1 mg/kg) + aerobic exercise (CAE, n = 11). The CRE group performed progressive ladder exercise (starting with 10% of body weight on a 1-m ladder with 2-cm-interval grids, at 85°) for 8 weeks. The CAE group exercised by treadmill running (20 m/min for 60 min daily, 4 times/week) for 8 weeks. Compared with the CC group, the levels of the autophagy-related factors BNIP3, Beclin 1, LC3-II/I ratio, p62, and FOXO3a in the gastrocnemius and soleus muscles were significantly decreased in the CRE and CAE groups. The CRE and CAE groups further showed significantly decreased MuRF 1 and Atrogin-1 levels and increased phosphorylation of AKT, FOXO3a, and PGC1-α. These results suggest that both ladder and aerobic exercise directly affected muscle wasting by modulating the AKT/PGC1-α/FOXO3a signaling pathways regardless of the skeletal muscle type.

Effects of Muscular Endurance Exercise and Supplement Intake on Appendicular Skeletal Muscle and Muscle Function-Related Physical Strength, Blood Lipids, and IGF-1 in Obese Older Adults with Sarcopenia (근감소성(sarcopenia) 비만 노인의 근지구력 운동과 보충제 섭취가 사지 근육량과 근기능 관련 체력과 혈중지질 및 IGF-1에 미치는 영향)

  • Jae-Suk Shin;Hyun-Jun Kim
    • Journal of The Korean Society of Integrative Medicine
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    • v.11 no.4
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    • pp.95-104
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    • 2023
  • Purpose : This study aimed to introduce a 12-week muscular endurance exercise program and β-glucan consumption to obese elderly people with sarcopenia. We evaluated the program's impact on appendicular skeletal muscle strength and function, muscle function-related physical strength, blood lipids, and IGF-1. The results will serve as foundational data for preventing and improving sarcopenia. Methods : Forty elderly people aged 65 or older were recruited and underwent dual-energy X-ray absorptiometry. Based on criteria related to appendicular skeletal muscle mass (ASM/Height2: less than 5.4 kg/m2) and body fat percentage (at least 30% for women and 25% for men), we selected 24 obese elderly people with sarcopenia and excluded 56 who did not meet the criteria. Variables related to sarcopenia, blood lipids, IGF-1, and muscle function were measured before the 12-week muscular endurance exercise program. Results : In sarcopenic obese elderly participants, the 12-week muscular endurance exercise program significantly increased bone density and muscle mass while decreasing fat mass and percentage (p<.05). This program also improved grip strength, static balance, and SPPB in sarcopenic obese older adults. Furthermore, their 6-minute walk distance significantly increased (p<.05). Conclusion : Muscular endurance exercises combined with supplement intake can increase appendicular skeletal muscle and improve muscle strength and function, thereby improving the daily physical performance of the elderly.

Prognostic Value of Artificial Intelligence-Driven, Computed Tomography-Based, Volumetric Assessment of the Volume and Density of Muscle in Patients With Colon Cancer

  • Minsung Kim;Sang Min Lee;Il Tae Son;Taeyong Park;Bo Young Oh
    • Korean Journal of Radiology
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    • v.24 no.9
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    • pp.849-859
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    • 2023
  • Objective: The prognostic value of the volume and density of skeletal muscles in the abdominal waist of patients with colon cancer remains unclear. This study aimed to investigate the association between the automated computed tomography (CT)-based volume and density of the muscle in the abdominal waist and survival outcomes in patients with colon cancer. Materials and Methods: We retrospectively evaluated 474 patients with colon cancer who underwent surgery with curative intent between January 2010 and October 2017. Volumetric skeletal muscle index and muscular density were measured at the abdominal waist using artificial intelligence (AI)-based volumetric segmentation of body composition on preoperative pre-contrast CT images. Patients were grouped based on their skeletal muscle index (sarcopenia vs. not) and muscular density (myosteatosis vs. not) values and combinations (normal, sarcopenia alone, myosteatosis alone, and combined sarcopenia and myosteatosis). Postsurgical disease-free survival (DFS) and overall survival (OS) were analyzed using univariable and multivariable analyses, including multivariable Cox proportional hazard regression. Results: Univariable analysis showed that DFS and OS were significantly worse for the sarcopenia group than for the non-sarcopenia group (P = 0.044 and P = 0.003, respectively, by log-rank test) and for the myosteatosis group than for the non-myosteatosis group (P < 0.001 by log-rank test for all). In the multivariable analysis, the myosteatotic muscle type was associated with worse DFS (adjusted hazard ratio [aHR], 1.89 [95% confidence interval, 1.25-2.86]; P = 0.003) and OS (aHR, 1.90 [95% confidence interval, 1.84-3.04]; P = 0.008) than the normal muscle type. The combined muscle type showed worse OS than the normal muscle type (aHR, 1.95 [95% confidence interval, 1.08-3.54]; P = 0.027). Conclusion: Preoperative volumetric sarcopenia and myosteatosis, automatically assessed from pre-contrast CT scans using AI-based software, adversely affect survival outcomes in patients with colon cancer.

Effects of cisplatin on mitochondrial function and autophagy-related proteins in skeletal muscle of rats

  • Seo, Dae Yun;Bae, Jun Hyun;Zhang, Didi;Song, Wook;Kwak, Hyo-Bum;Heo, Jun-Won;Jung, Su-Jeen;Yun, Hyeong Rok;Kim, Tae Nyun;Lee, Sang Ho;Kim, Amy Hyein;Jeong, Dae Hoon;Kim, Hyoung Kyu;Han, Jin
    • BMB Reports
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    • v.54 no.11
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    • pp.575-580
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    • 2021
  • Cisplatin is widely known as an anti-cancer drug. However, the effects of cisplatin on mitochondrial function and autophagy-related proteins levels in the skeletal muscle are unclear. The purpose of this study was to investigate the effect of different doses of cisplatin on mitochondrial function and autophagy-related protein levels in the skeletal muscle of rats. Eight-week-old male Wistar rats (n = 24) were assigned to one of three groups; the first group was administered a saline placebo (CON, n = 10), and the second and third groups were given 0.1 mg/kg body weight (BW) (n = 6), and 0.5 mg/kg BW (n = 8) of cisplatin, respectively. The group that had been administered 0.5 mg cisplatin exhibited a reduced BW, skeletal muscle tissue weight, and mitochondrial function and upregulated levels of autophagy-related proteins, including LC3II, Beclin 1, and BNIP3. Moreover, this group had a high LC3 II/I ratio in the skeletal muscle; i.e., the administration of a high dose of cisplatin decreased the muscle mass and mitochondrial function and increased the levels of autophagy-related proteins. These results, thus, suggest that reducing mitochondrial dysfunction and autophagy pathways may be important for preventing skeletal muscle atrophy following cisplatin administration.

Swim Training Improves Fitness in High Fat Diet-fed Female Mice

  • Jun, Jong-Kui;Lee, Wang-Lok;Lee, Young-Ran;Jeong, Sun-Hyo
    • Biomedical Science Letters
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    • v.16 no.3
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    • pp.151-159
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    • 2010
  • The peroxisome proliferator-activated receptor α (PPARα) is a nuclear transcription factor that plays a central role in lipid metabolism and obesity. Exercise also is a powerful modifier of the manifestations of the lipid metabolism and obesity in animal models and humans with obesity and metabolic syndrome. However, effects of exercise on lipid metabolism and obesity in normal-weight younger female subjects, having functional ovaries and not metabolic disease, remain unexplained. To explore the effects of exercise on the development of obesity and its molecular mechanism in high fat diet-fed female C57BL/6J mice, we experimented the effects of swim training on body weight, adipose tissue mass, serum lipid levels, morphological changes of adipocytes and the expression of PPARα target genes involved in fat oxidation in skeletal muscle tissue of female C57BL/6J mice. Swim-trained mice had significantly decreased body weight, adipose tissue mass, serum triglycerides compared with female control mice. Histological studies showed that swim training significantly decreased the average size of adipoctyes in parametrial adipose tissue. Swim training did not affect the expression of PPARα mRNA in skeletal muscle. Concomitantly, swim training did not increase mRNA levels of PPARα target genes responsible for fatty acid β-oxidation, such as carnitine palmitoyltransferase 1, medium chain acyl-CoA dehydrogenase, enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase, and thiolase in skeletal muscle. In conclusion, these results indicate that swim training regulates lipid metabolism and obesity in high fat diet fed-female mice although swim training did not increase mRNA levels of PPARα target genes involved in fatty acid β-oxidation in skeletal muscle, suggesting that swim training may prevent obesity and improve fitness through other mechanisms in female with ovaries, not through the activation of skeletal muscle PPARα.

Insulin Resistance of Skeletal Muscle was Recovered by Leptin Injection in vivo, but not in vitro, in High-fat Diet Fed Rats

  • Doh, Kyung-Oh;Park, Jeong-Oak;Jeon, Jeong-Ryne;Kim, Jong-Yeon
    • The Korean Journal of Physiology and Pharmacology
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    • v.9 no.2
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    • pp.125-130
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    • 2005
  • We examined the effect of leptin on the insulin resistance in skeletal muscles by measuring the glucose transport. Male Wistar rats were fed with chow or high-fat diets for 30 days. Three days before sacrifice, high-fat fed rats were subcutaneously injected with leptin (1 mg/kg body weight) for 3 days. The glucose transports in the epitrochlearis and soleus muscle were not different among the experimental groups under basal state, however these were decreased significantly in the high fat-diet rats under insulin-stimulation (p<0.01). Leptin treatment recovered the decreased glucose transport in the epitrochlearis (p<0.05) and soleus (p=0.08). Triglyceride concentration in the soleus muscle was increased significantly in the high fat-fed rats, compared to chow diet rats (p<0.01), and it was decreased significantly by leptin treatment (p<0.01). The glucose transport was measured under basal and 60μu/ml of insulin with or without 50 ng/ml of leptin. Leptin had no direct stimulatory effect on glucose transport under both basal and insulin-stimulated conditions in vitro. These results demonstrate that leptin injection to high fat diet fed rats recovered impaired insulin responsiveness of the skeletal muscles and muscle triglyceride concentration. However, there was no direct stimulatory effect of leptin on insulin sensitivity of the skeletal muscle in vitro.

Effects of the Protein Fraction of Panax ginseng on Primary Cultured Chicken Skeletal Muscle Cells (인삼 단백분획물이 일차배양한 계배의 근육세포에 미치는 영향)

  • Park, Mi-Jung;Song, Jin-Ho;Lee, Heun-Pa;Kim, Young-Choong
    • Korean Journal of Pharmacognosy
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    • v.21 no.3
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    • pp.210-216
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    • 1990
  • Effects of the protein fraction of Panax ginseng on chicken embryonic skeletal muscle cells cultured with a decfiient medium were studied. The protein fraction was further fractionated into four groups according to the molecular weight; larger than 10,000 dalton(fraction A), between 5,000 and 10,000 dalton(fraction B), between 1,000 and 5,000 dalton(fraction C), between 500 and 1,000 dalton(fraction D). According to the microscopic observation, all four protein fractions at the concentration of 10100μg/ml showed the tendency to stimulate the growth and differentiation of the muscle cells. The activity of acetylcholinesterase in muscle cells was significantly elevated by the protein fraction A at the concentration of 100μg/ml. Protein fractions B,C and D significantly enhanced the synthesis of RNA in the muscle cells. The synthesis of DNA in muscle cells was significantly enhanced by protein fractions A,B and C.

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The effect of thalidomide on visceral fat pad mass and triglyceride concentration of the skeletal muscles in rats

  • Kim, Ki-Hoon;Choi, Chang-Bon;Kim, Jong-Yeon
    • Journal of Yeungnam Medical Science
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    • v.35 no.2
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    • pp.213-218
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    • 2018
  • Background: Body fats, especially both of abdominal fat pad mass and skeletal muscle fat content, are inversely related to insulin action. Therefore, methods for decreasing visceral fat mass and muscle triglyceride content may be helpful for the prevention of insulin resistance. Methods: Thalidomide, used for its anti-angiogenic and anti-inflammatory properties, was administered to rats for 4 weeks. A 10% solution of thalidomide in dimethyl sulfoxide was injected daily into the peritoneal cavity as much as 100 mg/kg of body weight. Results: The total visceral fat pad mass in the thalidomide-treated group was 11% lower than in the control group. The size of adipocytes of the epididymal fat pad mass in the thalidomide-treated group was smaller than in the control group. The intraperitoneal thalidomide treatment increased triglyceride concentrations by 16% in the red muscle, but not in the white muscle. Conclusion: The results suggested that intraperitoneal thalidomide treatment inhibited abdominal fat accumulation, and that the free fatty acids in the blood were preferentially accumulated in the red muscle rather than in the white muscle.