• Journal of Microbiology and Biotechnology
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• v.30 no.12
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• pp.1896-1904
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• 2020

Muscle atrophy, characterized by a reduced number and size of myofibers, occurs due to immobilization, aging, and several chronic diseases. Leonurus japonicus, belonging to the Labiatae family, is widely used as a traditional medicine in Korea, China, and Japan. Previous studies have reported that L. japonicus has various physiological activities, such as anti-bacteria, anti-cancer, and liver protection. Leonurine, which is a major bioactive in L. japonicas, is known to possess biological effects including anti-inflammation, anti-fibrosis, anti-angiogenesis, and anti-diabetes. However, the preventive effects of L. japonicas and leonurine on muscle have not been reported. The current study aimed to determine the inhibitory effects of standardized L. japonicus extract (LJE) and leonurine on muscle atrophy by clarifying their underlying molecular mechanisms in tumor necrosis factor-alpha (TNF-α)-stimulated L6 myotubes. LJE and leonurine stimulated the phosphatidylinositol 3-kinase/Akt pathway that was reduced by TNF-α treatment. LJE and leonurine not only increased the mammalian target of rapamycin pathway for protein anabolism but also decreased the mRNA expression of E3 ubiquitin ligases by blocking the translocation of Forkhead box O, which is closely linked with proteolysis. Additionally, LJE and leonurine alleviated inflammatory responses by downregulating TNF-α and interleukin-6 mRNA expression and reducing the protein expression of nuclear factor-kappa B, a major transcriptional factor of proinflammatory cytokines. Collectively, LJE and leonurine have potential as therapeutic candidates for inhibiting the development of skeletal muscle atrophy by activating the PI3K/Akt pathway and reducing inflammatory responses.

• Herbal Formula Science
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• v.30 no.4
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• pp.269-280
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• 2022

Objectives : In this study, it was investigated the effects of solid-phase fermentation extraction with Phellinus linteus of discarded Schisandra chinensis extract (PS) and its action mechanism on dexamethasone-induced muscle atrophy in mice. Methods : In mice, muscle atrophy model was induced by dexamethasone (5 mg/kg, I.p) once daily for 2 weeks and with PS extract administration (100 and 300 mg/kg, p.o.) as treatment groups. The changes in body weights, grip strength, Treadmill test, muscle weights, and the expression of atrophy-related genes were measured in muscle atrophy mice. The histological changes of gastrocnemius tissues were also observed by H&E staining with measurement of myofiber size. Results : The administration of PS extract increased significantly body weights, grip strength, treadmill test and muscle weights in muscle atrophy mice. PS extract administration increased significantly the area of myofibers and inhibited structural damages of muscle and increased significantly the expression of myogenin and decreased significantly the expression of MuRF1, Atrogin1 and phosphorylation of AMPK and PGC1α in muscle tissues of muscle atrophy mice. Conclusions : These results indicate that PS extract has a improvement effects on muscle atrophy with stimulation of myogenic differentiation and inhibition of mRNA degradation that could be related with the activation of AMPK and PGC1α signaling pathways in muscle. This suggests that PS extract can apply to treat muscle atrophy in clinics.

• Journal of Genetic Medicine
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• v.16 no.2
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• pp.67-70
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• 2019

Limb-girdle muscular dystrophy (LGMD) is a group of muscular dystrophies that has extremely heterogeneous clinical features and genetic background. The caveolin-3 gene (CAV3) is one of the causative genes. LGMD appears as a clinical continuum, from isolated skeletal muscle involvement to long QT syndrome. Here we report two patients without apparent muscle weakness in a family with CAV3 mutation. A 7-month-old Korean boy visited our muscle clinic because of an incidental finding of elevated serum creatine kinase (CK) concentration (680 IU/L, reference range, 20-270 IU/L) without clinical symptoms. The patient was born after an uneventful pregnancy and showed normal developmental milestones. He developed pseudohypertrophy of his calf muscle during the follow-up. We obtained a muscle biopsy at age 14 months, which showed size variations and degenerating/regenerating myofibers with endomysial fibrosis and immunohistochemical evidence of normal dystrophin. Under the impression of LGMD, we performed target panel sequencing and identified a heterozygous in-frame mutation of CAV3, c.307_312delGTGGTG (p.Val103_Val104del). Immunohistochemical staining of muscle indicated complete loss of caveolin-3 compared with normal control muscle, which supported the variant's pathogenicity. We performed segregation analysis and found that the patient's mother had the same variant with elevated serum CK level (972 IU/L). We report on autosomal dominant familial caveolinopathy caused by a pathogenic variant in CAV3, which was asymptomatic until the fourth decade. This case highlights the utility of next generation sequencing in the diagnosis of muscular dystrophies and the additive role of muscle biopsy to confirm the variants.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.11
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• pp.1807-1817
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• 2018

Objective: This study aimed at investigating white striping (WS) and wooden breast (WB) cases in breast meat collected from commercial broilers. Methods: A total of 183 breast samples were collected from male Ross 308 broilers slaughtered at the age of 6 weeks (n = 100) and 7 weeks (n = 83). The breasts were subjected to meat defect inspection, meat quality determination and histology evaluation. Results: Of 183, 4 breasts from 6-week-old broilers were classified as non-defective while the others exhibited the WS lesion. Among the 6-week-old birds, the defective samples from the medium size birds (carcass weight ${\leq}2.5kg$) showed mild to moderate WS degree with no altered meat quality. Some of the breasts from the 6-week-old birds with carcass weight above 2.5 kg exhibited WB in accompanied with the WS condition. Besides of a reduction of protein content, increases in collagen matter and pH values in the defective samples (p<0.05), no other impaired quality indices were detected within this group. All 7-week-old broilers yielded carcasses weighing above 2.5 kg and showed abnormal characteristics with progressive severity. The breasts affected with severe WS and WB showed the greatest cook loss, hardness, springiness and chewiness (p<0.05). Development of WB induced significantly increased drip loss in the samples (p<0.05). Histology indicated necrotic events in the defective myofibers. Based on logistic regression, increasing percent breast weight by one unit enhanced the chance of WS and WB development with advanced severity by 50.9% and 61.0%, respectively. Delayed slaughter age from 6 to 7 weeks increased the likelihood of obtaining increased WS severity by 56.3%. Conclusion: Cases of WS and WB defects in Southeast Asia have been revealed. Despite few cases of the severe WS and WB, such abnormal conditions significantly impaired technological properties and nutritional quality of broiler breasts.

• Molecules and Cells
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• v.21 no.2
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• pp.206-212
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• 2006

We have established in culture a spontaneously immortalized bovine embryonic fibroblast (BEF) cell line that has lost p53 and $p16^{INK4a}$ functions. MyoD is a muscle-specific regulator capable of inducing myogenesis in a number of cell types. When the BEF cells were transduced with MyoD they differentiated efficiently to desmin-positive myofibers in the presence of 2% horse serum and 1.7 nM insulin. The myogenic differentiation of this cell line was more rapid and obvious than that of C2C12 cells, as judged by morphological changes and expression of various muscle regulatory factors. To confirm that lack of the p53 and $p16^{INK4a}$ pathway does not prevent MyoD-mediated myogenesis, we established a cell line transformed with SV40LT (BEFV) and introduced MyoD into it. In the presence of 2% horse serum and 1.7 nM insulin, the MyoD-transduced BEFV cells differentiated like the MyoD-transduced BEFS cells, and displayed a similar pattern of expression of muscle regulatory proteins. Taken together, our results indicate that MyoD overexpression overcomes the defect in muscle differentiation associated with immortalization and cell transformation caused by the loss of p53 and Rb functions.