scholarly journals Lipid droplets contribute myogenic differentiation in C2C12 by promoting the remodeling of the acstin-filament

2021 ◽  
Vol 12 (12) ◽  
Author(s):  
Yanjie Tan ◽  
Yi Jin ◽  
Pengxiang Zhao ◽  
Jian Wu ◽  
Zhuqing Ren

AbstractLipid droplet (LD), a multi-functional organelle, is found in most eukaryotic cells. LDs participate in the regulation of many cellular processes including proliferation, stress, and apoptosis. Previous studies showed the athlete’s paradox that trained athletes accumulate LDs in their skeletal muscle. However, the impact of LDs on skeletal muscle and myogenesis is not clear. We discovered that C2C12 myoblast cells containing more LDs formed more multinucleated muscle fibers. We also discovered that LDs promoted cell migration and fusion by promoting actin-filaments remodeling. Mechanistically, two LD-proteins, Acyl-CoA synthetase long chain family member 3 (ACSL3) and lysophosphatidylcholine acyltransferase 1 (LPCAT1), medicated the recruitment of actinin proteins which contributed to actin-filaments formation on the surface of LDs. During remodeling, the actinin proteins on LDs surface translocated to actin-filaments via ARF1/COPI vesicles. Our study demonstrate LDs contribute to cell differentiation, which lead to new insight into the LD function.

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1479
Author(s):  
Karolina Archacka ◽  
Joanna Bem ◽  
Edyta Brzoska ◽  
Areta M. Czerwinska ◽  
Iwona Grabowska ◽  
...  

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.


2020 ◽  
Vol 178 (1) ◽  
pp. 189-200
Author(s):  
Jiongjie Jing ◽  
Yong Pu ◽  
Almudena Veiga-Lopez ◽  
Lihua Lyu

Abstract Bisphenols are endocrine disrupting chemicals to which humans are ubiquitously exposed to. Prenatal bisphenol A exposure can lead to insulin resistance. However, the metabolic effects of other emerging bisphenols, such as bisphenol S (BPS) and bisphenol F (BPF), are less understood. Because the skeletal muscle is the largest of the insulin target tissues, the goal of this study was to evaluate the effects of 2 emerging bisphenols (BPS and BPF) on cytotoxicity, proliferation, myogenic differentiation, and insulin responsiveness in skeletal muscle cells. We tested this using a dose-response approach in C2C12 mouse and L6 rat myoblast cell lines. The results showed that C2C12 mouse myoblasts were more susceptible to bisphenols compared with L6 rat myoblasts. In both cell lines, bisphenol A was more cytotoxic, followed by BPF and BPS. C2C12 myoblast proliferation was higher upon BPF exposure at the 10−4 M dose and the fusion index was increased after exposure to either BPF or BPS at doses over 10−10 M. Exposure to BPS and BPF also reduced baseline expression of p-AKT (Thr) and p-GSK-3β, but not downstream effectors such as mTOR and glucose transporter-4. In conclusion, at noncytotoxic doses, BPS and BPF can alter myoblast cell proliferation, differentiation, and partially modulate early effectors of the insulin receptor signaling pathway. However, BPS or BPF short-term exposure evaluated here does not result in impaired insulin responsiveness.


2021 ◽  
Author(s):  
Laura Rihani ◽  
Sophie Franzmeier ◽  
Wei Wu ◽  
Jürgen Schlegel

Abstract Background Satellite cells (SC) constitute the stem cell population of skeletal muscle tissue and are determinants for myogenesis. Aldehyde Dehydrogenase 1 (ALDH1) enzymatic activity correlates with myogenic properties of SCs and, recently, we could show co-localization of its isoforms ALDH1A1 and ALDH1A3 in SCs of human skeletal muscle. ALDH1 is not only the pacemaker enzyme in retinoic acid signaling and differentiation, but also protecting cell maintenance against oxidative stress products. However, the molecular mechanism of ALDH1 in SC activation and regulation of myogenesis has not yet been characterized. In regard of ALDH1A1 and ALDH1A1 expression in myogenesis human RH30 and murine C2C12 myoblast cell lines were investigated using Western Blot, Immunofluorescence and Aldefluor Assay. Results Here, we show, that isoforms ALDH1A1 and ALDH1A3 are pivotal factors in the process of myogenic differentiation, since ALDH1A1 knock-out and ALDH1A3 knock-out, respectively, impaired differentiation potential. Recombinant re-expression of ALDH1A1 and ALDH1A3, respectively, in corresponding ALDH1-isoform knock-out cells recovered their differentiation potential. Most interestingly, the chemical inhibition of enzymatic activity by disulfiram leads to ALDH1A1 and ALDH1A3 protein upregulation and subsequent myogenic differentiation. Conclusion Our findings indicate that ALDH1A1 and ALDH1A3 proteins are important for myogenic differentiation and, therefore, seem to be essential activators and regulators of SCs.


2020 ◽  
Author(s):  
Li Li ◽  
Xiao Zhang ◽  
Hailong Yang ◽  
Xiaoli Xu ◽  
Yuan Chen ◽  
...  

Abstract BackgroundAs a well-known cancer-related miRNA, miR-193b-3p is enriched in skeletal muscle but dysregulated in muscle disease. However, mechanism underpinning has not been addressed so far. MethodsHere, we probed the impact of miR-193b-3p on myogenesis by mainly using goat tissues and skeletal muscle satellite cells (MuSCs), with combined methods including RNA-seq to profile the transcriptome affected by miR-193b-3p, cell-counting kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) for cell proliferation assay, and RNA-RNA dual-labeled fluorescence in situ hybridization (FISH) for RNA colocalization. ResultsmiR-193b-3p is highly enriched in goat skeletal muscles, and ectopic miR-193b-3p promotes MuSCs proliferation and differentiation. Moreover, insulin-like growth factor-2 mRNA-binding protein 1 (IGF2BP1) is the most activated insulin signaling genes when overexpression miR-193b-3p and the miRNA recognition element (MRE) within IGF1BP1 3ʹ untranslated region (UTR) is indispensable for its activation caused by miR-193b-3p. Consistently, expression patterns and function of IGF2BP1 were similar to those of miR-193b-3p in tissues and MuSCs. While the overexpression of miR-193b-3p failed to induce pax7 expression and myoblast proliferation when IGF2BP1 knockdown. Furthermore, miR-193b-3p destabilized IGF2BP1 mRNA but unexpectedly promoted levels of IGF2BP1 heteronuclear RNA (hnRNA) dramatically. Moreover, miR-193b-3p could enhance fly luciferase activity when inserted upstream of its promoter, and induce neighboring genes of itself. However, miR-193b-3p inversely regulated IGF2BP1 and myoblast proliferation in mouse C2C12 myoblast. These data unveil that goat miR-193b-3p promotes myoblast proliferation via activating IGF2BP1 by binding on its 3ʹ UTR.ConclusionsOur novel findings highlight the positive regulation between miRNA and its target genes in muscle development, which further extends the repertoire of miRNA functions.


2017 ◽  
Vol 131 (15) ◽  
pp. 1919-1922 ◽  
Author(s):  
Gareth A. Nye ◽  
Giorgos K. Sakellariou ◽  
Hans Degens ◽  
Adam P. Lightfoot

Mitochondria are no longer solely regarded as the cellular powerhouse; instead, they are now implicated in mediating a wide-range of cellular processes, in the context of health and disease. A recent article in Clinical Science, Ventura-Clapier et al. highlights the role of sexual dimorphism in mitochondrial function in health and disease. However, we feel the authors have overlooked arguably one of the most mitochondria-rich organs in skeletal muscle. Many studies have demonstrated that mitochondria have a central role in mediating the pathogenesis of myopathologies. However, the impact of sexual dimorphism in this context is less clear, with several studies reporting conflicting observations. For instance in ageing studies, a rodent model reported female muscles have higher antioxidant capacity compared with males; in contrast, human studies demonstrate no sex difference in mitochondrial bioenergetics and oxidative damage. These divergent observations highlight the importance of considering models and methods used to examine mitochondrial function, when interpreting these data. The use of either isolated or intact mitochondrial preparations in many studies appears likely to be a source of discord, when comparing many studies. Overall, it is now clear that more research is needed to determine if sexual dimorphism is a contributing factor in the development of myopathologies.


Author(s):  
Manuel Schmidt ◽  
Anja Weidemann ◽  
Christine Poser ◽  
Anne Bigot ◽  
Julia von Maltzahn

Myogenic differentiation, muscle stem cell functionality, and regeneration of skeletal muscle are cellular processes under tight control of various signaling pathways. Here, we investigated the role of non-canonical NF-κB signaling in myogenic differentiation, muscle stem cell functionality, and regeneration of skeletal muscle. We stimulated non-canonical NF-κB signaling with an agonistically acting antibody of the lymphotoxin beta receptor (LTβR). Interestingly, we found that stimulation of non-canonical NF-κB signaling through the LTβR agonist impairs myogenic differentiation, muscle stem cell function, and regeneration of skeletal muscle. Furthermore, we show that stimulation of non-canonical NF-κB signaling by the LTβR agonist coincides with activation of canonical NF-κB signaling. We suggest a direct crosstalk between canonical and non-canonical NF-κB signaling during myogenic differentiation which is required for proper myogenic differentiation and thereby regeneration of skeletal muscle.


2018 ◽  
Vol 10 (2) ◽  
pp. 102-117 ◽  
Author(s):  
Giuseppe Militello ◽  
Mohammed Rabiul Hosen ◽  
Yuliya Ponomareva ◽  
Pascal Gellert ◽  
Tyler Weirick ◽  
...  

Abstract Myogenesis is a complex process required for skeletal muscle formation during embryonic development and for regeneration and growth of myofibers in adults. Accumulating evidence suggests that long non-coding RNAs (lncRNAs) play key roles in regulating cell fate decision and function in various tissues. However, the role of lncRNAs in the regulation of myogenesis remains poorly understood. In this study, we identified a novel muscle-enriched lncRNA called ‘Myolinc (AK142388)’, which we functionally characterized in the C2C12 myoblast cell line. Myolinc is predominately localized in the nucleus, and its levels increase upon induction of the differentiation. Knockdown of Myolinc impairs the expression of myogenic regulatory factors and formation of multi-nucleated myotubes in cultured myoblasts. Myolinc also regulates the expression of Filip1 in a cis-manner. Similar to Myolinc, knockdown of Filip1 inhibits myogenic differentiation. Furthermore, Myolinc binds to TAR DNA-binding protein 43 (TDP-43), a DNA/RNA-binding protein that regulates the expression of muscle genes (e.g. Acta1 and MyoD). Knockdown of TDP-43 inhibits myogenic differentiation. We also show that Myolinc−TDP-43 interaction is essential for the binding of TDP-43 to the promoter regions of muscle marker genes. Finally, we show that silencing of Myolinc inhibits skeletal muscle regeneration in adult mice. Altogether, our study identifies a novel lncRNA that controls key regulatory networks of myogenesis.


2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 1010-1010
Author(s):  
Giulia Lizzo ◽  
Kamila Muller ◽  
Jonathan Thevenet ◽  
Stefan Christen ◽  
Kim Zarse ◽  
...  

Abstract Glycine is the simplest amino acid and it has a pivotal role in different metabolic processes, such as being a building block of glutathione, collagen and purine bases, or taking part in methylation reactions, detoxication and ammonia metabolism. Although considered for many years a non-essential amino acid, glycine levels are decreased in certain conditions, as the endogenous synthesis cannot fulfill the needs required to sustain all the cellular processes in which glycine is involved. Here we describe that glycine levels are significantly lower in skeletal muscle of aged zebrafish and mice and in plasma of humans compared to young subjects. We therefore fed healthy old mice for 6 weeks with a glycine-supplemented diet and observed a significant restoration of glycine levels in skeletal muscle and liver towards young mouse levels. Moreover, old mice showed decreased mitochondrial function in glycolytic and oxidative fibers, and a significant increase in oxygen consumption was observed in glycolytic fibers after glycine supplementation. The improvement of mitochondrial function is not associated to an increased mitochondrial biogenesis or an increased antioxidant capacity, but glycine supplementation increases both total GSH and GSSG levels, suggestive of a pro-oxidant environment. Overall, glycine supplementation induced an increase in the cross-sectional area of fibers. Finally, we carried out RNA-Seq study to decipher the impact of higher glycine intake. Our results suggest that age-associated glycine deficiency plays an important role in atrophy of muscle, especially in glycolytic fibers, and is reversible with a dietary supplementation.


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