miR-34b Modulates Skeletal Muscle Cell Proliferation and Differentiation

2017 ◽  
Vol 118 (12) ◽  
pp. 4285-4295 ◽  
Author(s):  
Zhixiong Tang ◽  
Huiling Qiu ◽  
Lan Luo ◽  
Nian Liu ◽  
Jiasheng Zhong ◽  
...  
2019 ◽  
Vol 127 (2) ◽  
pp. 342-355 ◽  
Author(s):  
Cecilie J. L. Bechshøft ◽  
Peter Schjerling ◽  
Michael Kjaer ◽  
Abigail L. Mackey

Underpinning skeletal muscle plasticity is the interplay between many cell types, of which fibroblasts are emerging as potent players, both negatively in the development of fibrosis but also positively in stimulating muscle repair through enhancing myogenesis. The mechanisms behind this interaction however remain unknown. To investigate this, waste hamstring muscle tissue was obtained from eight healthy young men undergoing reconstructive anterior cruciate ligament surgery and primary myoblasts and fibroblasts were isolated. Myoblasts were cultured alone or with fibroblasts, either in direct or indirect contact (separated by an insert with a permeable membrane). The myogenesis parameters proliferation, differentiation, and fusion were determined from immunostained cells, while, in replicate samples, gene expression levels of GAPDH, Ki67, Pax7, MyoD, myogenin, myomaker, MHC-Iβ, TCF7L2, COL1A1, and p16 were determined by RT-PCR. We found only trends for an influence of skeletal muscle fibroblasts on myogenic cell proliferation and differentiation. While greater mRNA levels of GAPDH, Pax7, MyoD, myogenin, and MHC-Iβ were observed in myogenic cells in indirect contact with fibroblasts (insert) when compared with cells cultured alone, a similar effect of an empty insert was also observed. In conclusion we find very little influence of skeletal muscle fibroblasts on myoblasts derived from the same tissue, although it cannot be excluded that a different outcome would be seen under less optimal myogenic growth conditions. NEW & NOTEWORTHY Using passage one primary myoblasts and fibroblasts isolated from human skeletal muscle, we found only a trend for an effect of skeletal muscle fibroblasts on myogenic cell proliferation and differentiation. This is contrary to previous reports and raises the possibility that fibroblasts of different tissue origins exert distinct roles.


2020 ◽  
Author(s):  
Amina El Ayadi ◽  
Melody R.S. Threlkeld ◽  
Steven E. Wolf ◽  
Juquan Song

Abstract Background: Skeletal muscle injury leads to loss of muscle function that lasts well into recovery and can be permanent. Application of the novel bio-scaffold termed porcine-derived urinary bladder matrix (UBM) has a potential benefit to mitigate injury through tissue regeneration. To date, findings of potential benefit in animal models were limited to short assessment times. The purpose of this study was to investigate whether UBM treatment 14 days after injury sustainably improves the recovery of muscle function in injured mice. Methods: C57BL/6 adult male mice received bilateral laceration injuries on the gastrocnemius (GN) muscle under anesthesia and were then treated with vehicle or 150 µg of UBM nanoparticles. Treatment was applied immediately after injury or 14 days later. Muscle isometric force was measured 60 days after injury. Previous time course analyses have shown that muscle function did not start to improve until after 42 days after injury. Therefore, we designed a second experiment to trace the time course of UBM effects on muscle function recovery by measuring the isometric muscle force at 49 and 90 days after injury. In vitro, we analyzed the effects of UBM on muscle cell proliferation and differentiation. Results: UBM promotes muscle cell proliferation and differentiation. Twitch (Pt), tetanic (Po) force and maximal fatigue were significantly decreased in the injured mice on day 60. Muscle fatigue maximum force significantly recovered when UBM treatment was applied 14 days after injury (p<0.05) but not when UBM was applied immediately after the injury. Time course analysis demonstrated that UBM improvement of Pt and Po was evident by day 49 after injury (p<0.05). However, no further muscle function improvement was observed on day 90. Conclusions: Delayed treatment with the UBM improves muscle function recovery following laceration injury starting 49 days after injury. These effects may be mediated by improvements in muscle cell proliferation and differentiation. This animal model is suitable to test other therapeutic strategies to improve muscle function after injury.


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 97-97
Author(s):  
Zong-ming Zhang ◽  
Chun-qi Gao ◽  
Hui-chao Yan ◽  
Xiu-qi Wang

Abstract Wnt/β-catenin plays a crucial role in skeletal muscle growth, but its specific mechanism still unclear. In this study, due to the distinct role of lysine in pig industry, we provided it as an entry point to investigate the role of Wnt/β-catenin in governing skeletal muscle growth. Firstly, total 18 weaned piglets were divided into three groups: control group, lysine deficiency group and lysine re-supplementation group (lysine levels added from 0.83% to 1.31% at 14 d). After 28 d experiment, all pigs were slaughtered to measure the change of Wnt/β-catenin in skeletal muscle. Secondly, satellite cell (SC) was isolated and cultured with Wnt activator, such as Wnt3a and WRN (Wnt3a, R-spondin1, Noggin) after lysine deficiency for 48 h to investigate cell proliferation and differentiation ability and the level of Wnt/β-catenin in different conditions. The results showed that compared with the control group, lysine deficiency significantly reduced longissimus dorsi muscle weight and Pax7 positive SC, and inhibited Wnt/β-catenin (P &lt; 0.05). Fortunately, these restrictions were rescued to the control levels by lysine re-supplementation (P &gt; 0.05). Meanwhile, compared with the lysine deficiency group, the MTT and western blotting assay showed cell proliferation ability was significantly increased with re-activated Wnt/β-catenin by re-supplemented lysine, Wnt3a or WRN (P &lt; 0.05), respectively. Moreover, under the condition of cell differentiation, compared with the control group, cell fusion index was significantly decreased in the lysine deficiency group (P &lt; 0.05), whereas it was significantly increased with lysine re-supplementation group, Wnt3a or WRN respective supplementation group in comparison with the lysine deficiency group (P &lt; 0.05). In addition, compared with the lysine deficiency group, the protein levels of myogenic regulatory factors and Wnt/β-catenin pathway were also re-activated by re-supplemented lysine, Wnt3a or WRN (P &lt; 0.05). Collectively, we found Wnt/β-catenin activation is required for porcine SC proliferation and differentiation to promote skeletal muscle growth.


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