scholarly journals Analyzing Satellite Cell Function During Skeletal Muscle Regeneration by Cardiotoxin Injury and Injection of Self-delivering siRNA In Vivo

10.3791/60194 ◽  
2019 ◽  
Author(s):  
Hellen E. Ahrens ◽  
Henriette Henze ◽  
Svenja C. Schüler ◽  
Manuel Schmidt ◽  
Sören S. Hüttner ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cell ◽  
Muscle Regeneration ◽  
Cell Function ◽  
Skeletal Muscle Regeneration

scholarly journals PEDF-derived peptide promotes skeletal muscle regeneration through its mitogenic effect on muscle progenitor cells

2015 ◽  
Vol 309 (3) ◽  
pp. C159-C168 ◽  
Author(s):  
Tsung-Chuan Ho ◽  
Yi-Pin Chiang ◽  
Chih-Kuang Chuang ◽  
Show-Li Chen ◽  
Jui-Wen Hsieh ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cell Proliferation ◽  
Cyclin D1 ◽  
Satellite Cell ◽  
Muscle Regeneration ◽  
Muscle Fibers ◽  
Skeletal Muscle Regeneration ◽  
Satellite Cell Proliferation

In response injury, intrinsic repair mechanisms are activated in skeletal muscle to replace the damaged muscle fibers with new muscle fibers. The regeneration process starts with the proliferation of satellite cells to give rise to myoblasts, which subsequently differentiate terminally into myofibers. Here, we investigated the promotion effect of pigment epithelial-derived factor (PEDF) on muscle regeneration. We report that PEDF and a synthetic PEDF-derived short peptide (PSP; residues Ser93-Leu112) induce satellite cell proliferation in vitro and promote muscle regeneration in vivo. Extensively, soleus muscle necrosis was induced in rats by bupivacaine, and an injectable alginate gel was used to release the PSP in the injured muscle. PSP delivery was found to stimulate satellite cell proliferation in damaged muscle and enhance the growth of regenerating myofibers, with complete regeneration of normal muscle mass by 2 wk. In cell culture, PEDF/PSP stimulated C2C12 myoblast proliferation, together with a rise in cyclin D1 expression. PEDF induced the phosphorylation of ERK1/2, Akt, and STAT3 in C2C12 myoblasts. Blocking the activity of ERK, Akt, or STAT3 with pharmacological inhibitors attenuated the effects of PEDF/PSP on the induction of C2C12 cell proliferation and cyclin D1 expression. Moreover, 5-bromo-2′-deoxyuridine pulse-labeling demonstrated that PEDF/PSP stimulated primary rat satellite cell proliferation in myofibers in vitro. In summary, we report for the first time that PSP is capable of promoting the regeneration of skeletal muscle. The signaling mechanism involves the ERK, AKT, and STAT3 pathways. These results show the potential utility of this PEDF peptide for muscle regeneration.

scholarly journals Canonical NF-κB signaling regulates satellite stem cell homeostasis and function during regenerative myogenesis

2018 ◽  
Vol 11 (1) ◽  
pp. 53-66 ◽  
Author(s):  
Alex R Straughn ◽  
Sajedah M Hindi ◽  
Guangyan Xiong ◽  
Ashok Kumar
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cell ◽  
Satellite Cells ◽  
Muscle Regeneration ◽  
Cell Function ◽  
Skeletal Muscle Regeneration ◽  
Cell Homeostasis ◽  
Adult Skeletal Muscle ◽  
Adult Mice ◽  
And Function

Abstract Skeletal muscle regeneration in adults is attributed to the presence of satellite stem cells that proliferate, differentiate, and eventually fuse with injured myofibers. However, the signaling mechanisms that regulate satellite cell homeostasis and function remain less understood. While IKKβ-mediated canonical NF-κB signaling has been implicated in the regulation of myogenesis and skeletal muscle mass, its role in the regulation of satellite cell function during muscle regeneration has not been fully elucidated. Here, we report that canonical NF-κB signaling is induced in skeletal muscle upon injury. Satellite cell-specific inducible ablation of IKKβ attenuates skeletal muscle regeneration in adult mice. Targeted ablation of IKKβ also reduces the number of satellite cells in injured skeletal muscle of adult mice, potentially through inhibiting their proliferation and survival. We also demonstrate that the inhibition of specific components of the canonical NF-κB pathway causes precocious differentiation of cultured satellite cells both ex vivo and in vitro. Finally, our results highlight that the constitutive activation of canonical NF-κB signaling in satellite cells also attenuates skeletal muscle regeneration following injury in adult mice. Collectively, our study demonstrates that the proper regulation of canonical NF-κB signaling is important for the regeneration of adult skeletal muscle.

Urokinase-dependent plasminogen activation is required for efficient skeletal muscle regeneration in vivo

Blood ◽  
2001 ◽  
Vol 97 (6) ◽  
pp. 1703-1711 ◽  
Author(s):  
Frederic Lluı́s ◽  
Josep Roma ◽  
Mònica Suelves ◽  
Maribel Parra ◽  
Gloria Aniorte ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Plasminogen Activator ◽  
Muscle Regeneration ◽  
Plasminogen Activators ◽  
Skeletal Muscle Regeneration ◽  
Plasminogen Activation ◽  
Wild Type ◽  
Type Plasminogen Activator ◽  
Deficient Mice

Plasminogen activators urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA) are extracellular proteases involved in various tissue remodeling processes. A requirement for uPA activity in skeletal myogenesis was recently demonstrated in vitro. The role of plasminogen activators in skeletal muscle regeneration in vivo in wild-type, uPA-deficient, and tPA-deficient mice is investigated here. Wild-type and tPA−/− mice completely repaired experimentally damaged skeletal muscle. In contrast, uPA−/− mice had a severe regeneration defect, with decreased recruitment of blood-derived monocytes to the site of injury and with persistent myotube degeneration. In addition, uPA-deficient mice accumulated fibrin in the degenerating muscle fibers; however, the defibrinogenation of uPA-deficient mice resulted in a correction of the muscle regeneration defect. A similar severe regeneration deficit with persistent fibrin deposition was also reproducible in plasminogen-deficient mice after injury, suggesting that fibrinolysis by uPA-mediated plasminogen activation plays a fundamental role in skeletal muscle regeneration. In conclusion, the uPA-plasmin system is identified as a critical component of the mammalian skeletal muscle regeneration process, possibly because it prevents intramuscular fibrin accumulation and contributes to the adequate inflammatory response after injury. These studies demonstrate the requirement of an extracellular proteolytic cascade during muscle regeneration in vivo.

scholarly journals MLL1 is required for PAX7 expression and satellite cell self-renewal in mice

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Gregory C. Addicks ◽  
Caroline E. Brun ◽  
Marie-Claude Sincennes ◽  
John Saber ◽  
Christopher J. Porter ◽  
...  
Keyword(s):  
Satellite Cell ◽  
Satellite Cells ◽  
Transcriptional Activation ◽  
Cell Activation ◽  
Target Genes ◽  
Cell Function ◽  
Skeletal Muscle Regeneration ◽  
Differentiation Potential ◽  
Self Renewal

Abstract PAX7 is a paired-homeobox transcription factor that specifies the myogenic identity of muscle stem cells and acts as a nodal factor by stimulating proliferation while inhibiting differentiation. We previously found that PAX7 recruits the H3K4 methyltransferases MLL1/2 to epigenetically activate target genes. Here we report that in the absence of Mll1, myoblasts exhibit reduced H3K4me3 at both Pax7 and Myf5 promoters and reduced Pax7 and Myf5 expression. Mll1-deficient myoblasts fail to proliferate but retain their differentiation potential, while deletion of Mll2 had no discernable effect. Re-expression of PAX7 in committed Mll1 cKO myoblasts restored H3K4me3 enrichment at the Myf5 promoter and Myf5 expression. Deletion of Mll1 in satellite cells reduced satellite cell proliferation and self-renewal, and significantly impaired skeletal muscle regeneration. Pax7 expression was unaffected in quiescent satellite cells but was markedly downregulated following satellite cell activation. Therefore, MLL1 is required for PAX7 expression and satellite cell function in vivo. Furthermore, PAX7, but not MLL1, is required for Myf5 transcriptional activation in committed myoblasts.

scholarly journals Conditional Deletion of Dicer in Adult Mice Impairs Skeletal Muscle Regeneration

2019 ◽  
Vol 20 (22) ◽  
pp. 5686 ◽  
Author(s):  
Satoshi Oikawa ◽  
Minjung Lee ◽  
Takayuki Akimoto
Keyword(s):  
Skeletal Muscle ◽  
Muscle Regeneration ◽  
Myogenic Differentiation ◽  
Tibialis Anterior Muscle ◽  
Critical Factor ◽  
Skeletal Muscle Regeneration ◽  
Small Noncoding Rnas ◽  
Adult Mice

Skeletal muscle has a remarkable regenerative capacity, which is orchestrated by multiple processes, including the proliferation, fusion, and differentiation of the resident stem cells in muscle. MicroRNAs (miRNAs) are small noncoding RNAs that mediate the translational repression or degradation of mRNA to regulate diverse biological functions. Previous studies have suggested that several miRNAs play important roles in myoblast proliferation and differentiation in vitro. However, their potential roles in skeletal muscle regeneration in vivo have not been fully established. In this study, we generated a mouse in which the Dicer gene, which encodes an enzyme essential in miRNA processing, was knocked out in a tamoxifen-inducible way (iDicer KO mouse) and determined its regenerative potential after cardiotoxin-induced acute muscle injury. Dicer mRNA expression was significantly reduced in the tibialis anterior muscle of the iDicer KO mice, whereas the expression of muscle-enriched miRNAs was only slightly reduced in the Dicer-deficient muscles. After cardiotoxin injection, the iDicer KO mice showed impaired muscle regeneration. We also demonstrated that the number of PAX7+ cells, cell proliferation, and the myogenic differentiation capacity of the primary myoblasts did not differ between the wild-type and the iDicer KO mice. Taken together, these data demonstrate that Dicer is a critical factor for muscle regeneration in vivo.

scholarly journals Effects of intramuscular administration of 1α,25(OH)2D3 during skeletal muscle regeneration on regenerative capacity, muscular fibrosis, and angiogenesis

2016 ◽  
Vol 120 (12) ◽  
pp. 1381-1393 ◽  
Author(s):  
Ratchakrit Srikuea ◽  
Muthita Hirunsai
Keyword(s):  
Skeletal Muscle ◽  
Vitamin D ◽  
Protein Synthesis ◽  
Cell Differentiation ◽  
Satellite Cell ◽  
Muscle Regeneration ◽  
Fiber Type ◽  
Fiber Formation ◽  
Skeletal Muscle Regeneration ◽  
Type Composition

The recent discovery of the vitamin D receptor (VDR) in regenerating muscle raises the question regarding the action of vitamin D3 on skeletal muscle regeneration. To investigate the action of vitamin D3 on this process, the tibialis anterior muscle of male C57BL/6 mice (10 wk of age) was injected with 1.2% BaCl2 to induce extensive muscle injury. The bioactive form of vitamin D3 [1α,25(OH)2D3] was administered daily via intramuscular injections during the regenerative phase (days 4-7 postinjury). Physiological and supraphysiological doses of 1α,25(OH)2D3 relative to 1 μg/kg muscle wet weight and mouse body weight were investigated. Muscle samples were collected on day 8 postinjury to examine proteins related to vitamin D3 metabolism (VDR, CYP24A1, and CYP27B1), satellite cell differentiation and regenerative muscle fiber formation [myogenin and embryonic myosin heavy chain (EbMHC)], protein synthesis signaling (Akt, p70 S6K1, 4E-BP1, and myostatin), fiber-type composition (fast and slow MHCs), fibrous formation (vimentin), and angiogenesis (CD31). Administration of 1α,25(OH)2D3 at physiological and supraphysiological doses enhanced VDR expression in regenerative muscle. Moreover, CYP24A1 and vimentin expression was increased, accompanying decreased myogenin and EbMHC expression at the supraphysiological dose. However, there was no change in CYP27B1, Akt, p70 S6K1, 4E-BP1, myostatin, fast and slow MHCs, or CD31 expression at any dose investigated. Taken together, administration of 1α,25(OH)2D3 at a supraphysiological dose decreased satellite cell differentiation, delayed regenerative muscle fiber formation, and increased muscular fibrosis. However, protein synthesis signaling, fiber-type composition, and angiogenesis were not affected by either 1α,25(OH)2D3 administration at a physiological or supraphysiological dose.

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