Abstract 123: Ischemia Mediates Myogenic Progenitor Cell Dysfunction

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Matthew Fincher ◽  
David Abraham ◽  
Daryll Baker ◽  
Janice Tsui
Keyword(s):  
Skeletal Muscle ◽  
Western Blot ◽  
Satellite Cells ◽  
Progenitor Cell ◽  
Caspase 3 ◽  
Myogenic Differentiation ◽  
Critical Limb Ischaemia ◽  
Limb Ischaemia ◽  
Muscle Biopsies ◽  
Myogenic Progenitor

Introduction Treatment options for critical limb ischaemia (CLI) are limited. Recent evidence has suggested that even with successful revascularisation, patients often show little functional improvement. This has been attributed to a musculopathy that occurs in CLI. Myogenic progenitor satellite cells (SCs) provide skeletal muscle with an intrinsic ability to regenerate. It has been shown that there is an increase in SCs in ischaemic muscle, however their function in ischaemia is poorly understood and we hypothesize that ischaemia has a detrimental effect on SC function. Methods Gastrocnemius muscle biopsies were taken from CLI patients and compared with non ischaemic control biopsies. The phenotypical changes and frequency of satellite cells were investigated using PAX 7 immunohistochemistry and western blot. C2C12 myoblasts were used in vitro, to investigate the effect of ischaemia on muscle progenitor cell function. Myoblasts were exposed to simulated ischaemia for 24, 48 and 72hrs. Proliferation rates were assessed using an MTT assay. Differentiation and apoptosis were assessed by MYOD and cleaved caspase 3 western blotting respectively. Results There is an increased expression of PAX 7 in CLI muscle biopsies, shown by both immunostaining and western blot analysis, suggesting an increased number of SCs in ischaemic human skeletal muscle (p<0.05). Myoblasts cultured in ischaemic conditions demonstrated decreased cell proliferation, reduced myogenic differentiation (decreased MYOD expression), and increased apoptosis (increased cleaved caspase 3 expression). Conclusion Despite an upregulation of SCs in ischaemic tissue, their function is suppressed in ischaemic conditions and this may be contributing to the poor functional recovery of patients post revascularisation. Enhancement of muscle regeneration in ischaemia may be a useful therapeutic adjunct in the treatment of CLI.

Abstract 255: Cytoprotective Effects of Erythropoietin and Erythropoietin-derivatives in Ischaemic Human Myotubes and the Role of Pi3k/akt Signalling Pathway

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Rebekah Sian Hwee Yu ◽  
Daryll Baker ◽  
David Abraham ◽  
Janice Tsui
Keyword(s):  
Skeletal Muscle ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Caspase 3 ◽  
Signalling Pathway ◽  
Critical Limb Ischaemia ◽  
Human Myotubes ◽  
Muscle Biopsies

Objectives Erythropoietin (Epo) has tissue-protective effects in response to injury, acting through the EpoR-βcR heteroreceptor. We have previously demonstrated the presence and interaction of the EpoR and βcR in human skeletal muscle. Here we aim to investigate the potential cytoprotective effects of Epo and an Epo-derivative (ARA-290) in a human in vitro model of skeletal muscle and establish a potential downstream signalling pathway utilised in protecting cells from apoptosis (including Jak-2, PI3k/Akt, NFkB). Methods Gastrocnemius muscle biopsies were obtained from patients with critical limb ischaemia and control samples were obtained from non-ischaemic patients. Human myoblasts were isolated from muscle biopsies, cultured, and allowed to differentiate into myotubes in order to investigate the cytoprotective effects of Epo and ARA-290 on myotubes subjected to simulated ischaemia. The PI3k inhibitors, LY294002 and wortmannin, were then used to determine the role of PI3k/Akt pathway in mediating cytoprotection. Following this, inhibitors against the upstreatm (Jak-2) and downstream (NFkB) molecules were also investigated. Western blot analysis, using the pro-apoptotic marker cleaved caspase-3 was performed and compared with levels of Akt and phosphorylated-Akt, using western blot analysis. Results Exogenous administration of Epo and ARA-290 were able to ameliorate the ischaemia-induced apoptosis on isolated human myotubes as shown by a significant reduction in cleaved caspase-3 expression. Addition of all inhibitors, to ARA-290 or Epo pre-treated cells, abolished the reduction in apoptosis. Conclusion The ability of ARA-290 to attenuate apoptosis in human myotubes undergoing ischaemic insult suggests a potential role in tissue protection in skeletal muscle injury. We propose that the PI3k/Akt signalling pathway is involved in mediating this cytoprotection.

scholarly journals Caspase 3 cleavage of Pax7 inhibits self-renewal of satellite cells

2015 ◽  
Vol 112 (38) ◽  
pp. E5246-E5252 ◽  
Author(s):  
Sarah A. Dick ◽  
Natasha C. Chang ◽  
Nicolas A. Dumont ◽  
Ryan A. V. Bell ◽  
Charis Putinski ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cells ◽  
Posttranslational Modifications ◽  
Caspase 3 ◽  
Myogenic Differentiation ◽  
Skeletal Muscle Regeneration ◽  
Stem Cell Population ◽  
Myoblast Differentiation ◽  
Self Renewal

Compensatory growth and regeneration of skeletal muscle is dependent on the resident stem cell population, satellite cells (SCs). Self-renewal and maintenance of the SC niche is coordinated by the paired-box transcription factor Pax7, and yet continued expression of this protein inhibits the myoblast differentiation program. As such, the reduction or removal of Pax7 may denote a key prerequisite for SCs to abandon self-renewal and acquire differentiation competence. Here, we identify caspase 3 cleavage inactivation of Pax7 as a crucial step for terminating the self-renewal process. Inhibition of caspase 3 results in elevated Pax7 protein and SC self-renewal, whereas caspase activation leads to Pax7 cleavage and initiation of the myogenic differentiation program. Moreover, in vivo inhibition of caspase 3 activity leads to a profound disruption in skeletal muscle regeneration with an accumulation of SCs within the niche. We have also noted that casein kinase 2 (CK2)-directed phosphorylation of Pax7 attenuates caspase-directed cleavage. Together, these results demonstrate that SC fate is dependent on opposing posttranslational modifications of the Pax7 protein.

Skeletal Muscle Regeneration: MSC versus Satellite Cells

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P86-P86
Author(s):  
Jens Stern-Straeter ◽  
Juritz Stephanie ◽  
Gregor Bran ◽  
Frank Riedel ◽  
Haneen Sadick ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Stem Cells ◽  
Satellite Cell ◽  
Cell Cultures ◽  
Muscle Tissue ◽  
Satellite Cells ◽  
Myogenic Differentiation ◽  
Culture Conditions ◽  
Muscle Biopsies

Problem Differentiating stem cells into the myogenic linage in order to create functional muscle tissue is a challenging endeavour. In this work, adipose-derived mesenchymal stem cells (MSC) and satellite cells derived from muscle biopsies were compared regarding proliferation and myogenic differentiation potential under standardized cell culture conditions. This data was obtained in order to discover the most promising type of stem cell for regeneration of muscle tissue and to determine the optimal culture conditions for later clinical use. Methods Human MSC were isolated from adipose tissue, and primary human skeletal myoblasts were extracted from muscle biopsies by enzymatic digestion. Proliferation was analysed using the AlamarBlue® assay. Gene expression of marker genes – such as Myogenin, Myo D, Myf 5 and MHC – were analysed by RT-PCR. Immunostainings against desmin and sarcomeric-actin were performed as differentiation markers. Results MSC cell cultures showed a greater proliferation rate compared with satellite cell cultures. In both stem cell cultures, myogenic differentiation/heritage could be verified by immunostainings against the muscle-specific marker desmin. Gene expression and protein analysis revealed a more stable differentiation of human satellite cell cultures. Conclusion Characterization of both human MSC cultures and satellite cell cultures – and thereby an understanding of myogenesis – might lead to their clinical usage in skeletal muscle tissue engineering. The results in this study appear to indicate that human satellite cell cultures have a more stable differentiation under in vitro conditions and that they might offer a greater potential for skeletal muscle tissue engineering purposes. Significance Our study contributes to the understanding of myogenic differentiation of MSC and satellite cells and helps to improve culture systems for later clinical utilization.

scholarly journals Toll-Like Receptors in Ischaemia and Its Potential Role in the Pathophysiology of Muscle Damage in Critical Limb Ischaemia

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Hemanshu Patel ◽  
Sidney G. Shaw ◽  
Xu Shi-Wen ◽  
David Abraham ◽  
Daryll M. Baker ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Damage ◽  
Potential Role ◽  
Arterial Disease ◽  
Severe Form ◽  
Tissue Loss ◽  
Critical Limb Ischaemia ◽  
Limb Ischaemia ◽  
Toll Like Receptors ◽  
Skeletal Muscle Damage

Toll-like receptors (TLRs) are key receptors of the innate immune system which are expressed on immune and nonimmune cells. They are activated by both pathogen-associated molecular patterns and endogenous ligands. Activation of TLRs culminates in the release of proinflammatory cytokines, chemokines, and apoptosis. Ischaemia and ischaemia/reperfusion (I/R) injury are associated with significant inflammation and tissue damage. There is emerging evidence to suggest that TLRs are involved in mediating ischaemia-induced damage in several organs. Critical limb ischaemia (CLI) is the most severe form of peripheral arterial disease (PAD) and is associated with skeletal muscle damage and tissue loss; however its pathophysiology is poorly understood. This paper will underline the evidence implicating TLRs in the pathophysiology of cerebral, renal, hepatic, myocardial, and skeletal muscle ischaemia and I/R injury and discuss preliminary data that alludes to the potential role of TLRs in the pathophysiology of skeletal muscle damage in CLI.

scholarly journals The LIM domain protein nTRIP6 modulates the dynamics of myogenic differentiation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tannaz Norizadeh Abbariki ◽  
Zita Gonda ◽  
Denise Kemler ◽  
Pavel Urbanek ◽  
Tabea Wagner ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cells ◽  
Muscle Regeneration ◽  
Myogenic Differentiation ◽  
Skeletal Muscle Regeneration ◽  
Temporal Control ◽  
Lim Domain ◽  
Lim Domain Protein ◽  
Domain Protein

AbstractThe process of myogenesis which operates during skeletal muscle regeneration involves the activation of muscle stem cells, the so-called satellite cells. These then give rise to proliferating progenitors, the myoblasts which subsequently exit the cell cycle and differentiate into committed precursors, the myocytes. Ultimately, the fusion of myocytes leads to myofiber formation. Here we reveal a role for the transcriptional co-regulator nTRIP6, the nuclear isoform of the LIM-domain protein TRIP6, in the temporal control of myogenesis. In an in vitro model of myogenesis, the expression of nTRIP6 is transiently up-regulated at the transition between proliferation and differentiation, whereas that of the cytosolic isoform TRIP6 is not altered. Selectively blocking nTRIP6 function results in accelerated early differentiation followed by deregulated late differentiation and fusion. Thus, the transient increase in nTRIP6 expression appears to prevent premature differentiation. Accordingly, knocking out the Trip6 gene in satellite cells leads to deregulated skeletal muscle regeneration dynamics in the mouse. Thus, dynamic changes in nTRIP6 expression contributes to the temporal control of myogenesis.

scholarly journals MiR-27b Promotes Muscle Development by Inhibiting MDFI Expression

2018 ◽  
Vol 46 (6) ◽  
pp. 2271-2283 ◽  
Author(s):  
Lianjie Hou ◽  
Jian Xu ◽  
Yiren Jiao ◽  
Huaqin Li ◽  
Zhicheng Pan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Western Blot ◽  
Satellite Cells ◽  
Muscle Regeneration ◽  
Muscle Injury ◽  
Target Gene ◽  
Muscle Development ◽  
Muscle Satellite Cells ◽  
Qrt Pcr

Background/Aims: Skeletal muscle plays an essential role in the body movement. However, injuries to the skeletal muscle are common. Lifelong maintenance of skeletal muscle function largely depends on preserving the regenerative capacity of muscle. Muscle satellite cells proliferation, differentiation, and myoblast fusion play an important role in muscle regeneration after injury. Therefore, understanding of the mechanisms associated with muscle development during muscle regeneration is essential for devising the alternative treatments for muscle injury in the future. Methods: Edu staining, qRT-PCR and western blot were used to evaluate the miR-27b effects on pig muscle satellite cells (PSCs) proliferation and differentiation in vitro. Then, we used bioinformatics analysis and dual-luciferase reporter assay to predict and confirm the miR-27b target gene. Finally, we elucidate the target gene function on muscle development in vitro and in vivo through Edu staining, qRT-PCR, western blot, H&E staining and morphological observation. Result: miR-27b inhibits PSCs proliferation and promotes PSCs differentiation. And the miR-27b target gene, MDFI, promotes PSCs proliferation and inhibits PSCs differentiation in vitro. Furthermore, interfering MDFI expression promotes mice muscle regeneration after injury. Conclusion: our results conclude that miR-27b promotes PSCs myogenesis by targeting MDFI. These results expand our understanding of muscle development mechanism in which miRNAs and genes work collaboratively in regulating skeletal muscle development. Furthermore, this finding has implications for obtaining the alternative treatments for patients with the muscle injury.

scholarly journals Beneficial Effect of IL-4 and SDF-1 on Myogenic Potential of Mouse and Human Adipose Tissue-Derived Stromal Cells

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1479
Author(s):  
Karolina Archacka ◽  
Joanna Bem ◽  
Edyta Brzoska ◽  
Areta M. Czerwinska ◽  
Iwona Grabowska ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Satellite Cells ◽  
Stromal Cells ◽  
Muscle Regeneration ◽  
Myogenic Differentiation ◽  
Human Adipose Tissue ◽  
Skeletal Muscle Regeneration ◽  
Animal Cells ◽  
The Impact

Under physiological conditions skeletal muscle regeneration depends on the satellite cells. After injury these cells become activated, proliferate, and differentiate into myofibers reconstructing damaged tissue. Under pathological conditions satellite cells are not sufficient to support regeneration. For this reason, other cells are sought to be used in cell therapies, and different factors are tested as a tool to improve the regenerative potential of such cells. Many studies are conducted using animal cells, omitting the necessity to learn about human cells and compare them to animal ones. Here, we analyze and compare the impact of IL-4 and SDF-1, factors chosen by us on the basis of their ability to support myogenic differentiation and cell migration, at mouse and human adipose tissue-derived stromal cells (ADSCs). Importantly, we documented that mouse and human ADSCs differ in certain reactions to IL-4 and SDF-1. In general, the selected factors impacted transcriptome of ADSCs and improved migration and fusion ability of cells in vitro. In vivo, after transplantation into injured muscles, mouse ADSCs more eagerly participated in new myofiber formation than the human ones. However, regardless of the origin, ADSCs alleviated immune response and supported muscle reconstruction, and cytokine treatment enhanced these effects. Thus, we documented that the presence of ADSCs improves skeletal muscle regeneration and this influence could be increased by cell pretreatment with IL-4 and SDF-1.

scholarly journals Potential Role of Omega-3 Fatty Acids on the Myogenic Program of Satellite Cells

2016 ◽  
Vol 9 ◽  
pp. NMI.S27481 ◽  
Author(s):  
Amritpal S. Bhullar ◽  
Charles T. Putman ◽  
Vera C. Mazurak
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Satellite Cells ◽  
Muscle Regeneration ◽  
Myogenic Differentiation ◽  
Skeletal Muscle Regeneration ◽  
Stem Cell Population ◽  
Omega 3 Fatty Acids ◽  
Omega 3 ◽  
Myogenic Program

Skeletal muscle loss is associated with aging as well as pathological conditions. Satellite cells (SCs) play an important role in muscle regeneration. Omega-3 fatty acids are widely studied in a variety of muscle wasting diseases; however, little is known about their impact on skeletal muscle regeneration. The aim of this review is to evaluate studies examining the effect of omega-3 fatty acids, α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid on the regulation of SC proliferation and differentiation. This review highlights mechanisms by which omega-3 fatty acids may modulate the myogenic program of the stem cell population within skeletal muscles and identifies considerations for future studies. It is proposed that minimally three myogenic transcriptional regulatory factors, paired box 7 (Pax7), myogenic differentiation 1 protein, and myogenin, should be measured to confirm the stage of SCs within the myogenic program affected by omega-3 fatty acids.

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