scholarly journals Palmitic Acid-Induced miR-429-3p Impairs Myoblast Differentiation by Downregulating CFL2

2021 ◽  
Vol 22 (20) ◽  
pp. 10972
Author(s):  
Mai Thi Nguyen ◽  
Kyung-Ho Min ◽  
Wan Lee

MicroRNAs are known to play a critical role in skeletal myogenesis and maintenance, and cofilin-2 (CFL2) is necessary for actin cytoskeleton dynamics and myogenic differentiation. Nonetheless, target molecules and the modes of action of miRNAs, especially those responsible for the inhibitory mechanism on the myogenesis by saturated fatty acids (SFA) or obesity, still remain unclear. Here, we reported the role played by miR-429-3p on CFL2 expression, actin filament dynamics, myoblast proliferation, and myogenic differentiation in C2C12 cells. Palmitic acid (PA), the most abundant SFA in diet, inhibited the myogenic differentiation of myoblasts, accompanied by CFL2 reduction and miR-429-3p induction. Interestingly, miR-429-3p suppressed the expression of CFL2 by targeting the 3′UTR of CFL2 mRNA directly. Transfection of miR-429-3p mimic in myoblasts increased F-actin formation and augmented nuclear YAP level, thereby promoting cell cycle progression and myoblast proliferation. Moreover, miR-429-3p mimic drastically suppressed the expressions of myogenic factors, such as MyoD, MyoG, and MyHC, and impaired myogenic differentiation of C2C12 cells. Therefore, this study unveiled the crucial role of miR-429-3p in myogenic differentiation through the suppression of CFL2 and provided implications of SFA-induced miRNA in the regulation of actin dynamics and skeletal myogenesis.

2021 ◽  
Author(s):  
Siyi Xie ◽  
Chushan Fang ◽  
Yujie Gao ◽  
Jie Yan ◽  
Lina Luo ◽  
...  

Abstract Background: Skeletal muscle is composed of bundles of myofibers ensheathed by extracellular matrix networks. Malformation of skeletal muscle during embryonic development results in congenital myopathies. Disease mechanisms of congenital myopathies remain unclear. PINCH, an adaptor of focal adhesion complex, plays essential roles in multiple cellular processes and organogenesis. Elucidation of the molecular mechanisms underlying skeletal myogenesis will offer new insights into pathogenesis of myopathies.Methods: We generated muscle-specific PINCH knock-out mice to study the functional role of PINCH in skeletal myogenesis. Histologic and Transmission Electron Microscopy analysis demonstrated that Impaired myogenic differentiation and maturation in mice with PINCH1 being ablated in skeletal muscle progenitors, and Ablation of PINCH1 and PINCH2 resulted in reduced size of muscle fibers and impaired multinucleation; Cell culture and immunostaining showed that defects in myoblast fusion and cytoskeleton assembly in PINCH double mutant mice; Western blotting showed that defects in expression of cytoskeleton proteins and proteins involved in myogenesis in DMUT skeletal muscles.Results: Double ablation of PINCH1 and PINCH2 resulted in early postnatal lethality with reduced size of skeletal muscles and detachment of diaphragm muscles from the body wall. Myofibers of PINCH mutant myofibers failed to undergo multinucleation and exhibited disrupted sarcomere structures. The mutant myoblasts in culture were able to adhere to newly formed myotubes, but impeded in cell fusion and subsequent sarcomere genesis and cytoskeleton organization. Consistent with this, expression of integrin β1 and some cytoskeleton proteins, and phosphorylation of ERK and AKT were significantly reduced in PINCH mutants. Expression of MRF4, the most highly expressed myogenic factor at late stages of myogenesis, was abolished in PINCH mutants, that could contribute to observed phenotypes. In addition, mice with PINCH1 being ablated in myogenic progenitors exhibited only mild centronuclear myopathic changes, suggesting a compensatory role of PINCH2 in myogenic differentiation, indicating a critical role of PINCH proteins in myogenic differentiation.Conclusion: Our results demonstrated an essential role of PINCH in skeletal myogenic differentiation.


2020 ◽  
Vol 21 (24) ◽  
pp. 9445
Author(s):  
Mai Thi Nguyen ◽  
Kyung-Ho Min ◽  
Wan Lee

Skeletal myogenesis is a multi-stage process that includes the cell cycle exit, myogenic transcriptional activation, and morphological changes to form multinucleated myofibers. Recent studies have shown that saturated fatty acids (SFA) and miRNAs play crucial roles in myogenesis and muscle homeostasis. Nevertheless, the target molecules and myogenic regulatory mechanisms of miRNAs are largely unknown, particularly when myogenesis is dysregulated by SFA deposition. This study investigated the critical role played by miR-96-5p on the myogenic differentiation in C2C12 myoblasts. Long-chain SFA palmitic acid (PA) significantly reduced FHL1 expression and inhibited the myogenic differentiation of C2C12 myoblasts but induced miR-96-5p expression. The knockdown of FHL1 by siRNA stimulated cell proliferation and inhibited myogenic differentiation of myoblasts. Interestingly, miR-96-5p suppressed FHL1 expression by directly targeting the 3’UTR of FHL1 mRNA. The transfection of an miR-96-5p mimic upregulated the expressions of cell cycle-related genes, such as PCNA, CCNB1, and CCND1, and increased myoblast proliferation. Moreover, the miR-96-5p mimic inhibited the expressions of myogenic factors, such as myoblast determination protein (MyoD), myogenin (MyoG), myocyte enhancer factor 2C (MEF2C), and myosin heavy chain (MyHC), and dramatically impeded differentiation and fusion of myoblasts. Overall, this study highlights the role of miR-96-5p in myogenesis via FHL1 suppression and suggests a novel regulatory mechanism for myogenesis mediated by miRNA in a background of obesity.


Author(s):  
Hyunju Liu ◽  
Su-Mi Lee ◽  
Hosouk Joung

AbstractSUMOylation is one of the post-translational modifications that involves the covalent attachment of the small ubiquitin-like modifier (SUMO) to the substrate. SUMOylation regulates multiple biological processes, including myoblast proliferation, differentiation, and apoptosis. 2-D08 is a synthetically available flavone, which acts as a potent cell-permeable SUMOylation inhibitor. Its mechanism of action involves preventing the transfer of SUMO from the E2 thioester to the substrate without influencing SUMO-activating enzyme E1 (SAE-1/2) or E2 Ubc9-SUMO thioester formation. However, both the effects and mechanisms of 2-D08 on C2C12 myoblast cells remain unclear. In the present study, we found that treatment with 2-D08 inhibits C2C12 cell proliferation and differentiation. We confirmed that 2-D08 significantly hampers the viability of C2C12 cells. Additionally, it inhibited myogenic differentiation, decreasing myosin heavy chain (MHC), MyoD, and myogenin expression. Furthermore, we confirmed that 2-D08-mediated anti-myogenic effects impair myoblast differentiation and myotube formation, reducing the number of MHC-positive C2C12 cells. In addition, we found that 2-D08 induces the activation of ErK1/2 and the degradation of MyoD and myogenin in C2C12 cells. Taken together, these results indicated that 2-D08 treatment results in the deregulated proliferation and differentiation of myoblasts. However, further research is needed to investigate the long-term effects of 2-D08 on skeletal muscles.


Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2725
Author(s):  
Mai Thi Nguyen ◽  
Wan Lee

Skeletal myogenesis is required to maintain muscle mass and integrity, and impaired myogenesis is causally linked to the etiology of muscle wasting. Recently, it was shown that excessive uptake of saturated fatty acids (SFA) plays a significant role in the pathogenesis of muscle wasting. Although microRNA (miRNA) is implicated in the regulation of myogenesis, the molecular mechanism whereby SFA-induced miRNAs impair myogenic differentiation remains largely unknown. Here, we investigated the regulatory roles of miR-325-3p on CFL2 expression and myogenic differentiation in C2C12 myoblasts. PA impeded myogenic differentiation, concomitantly suppressed CFL2 and induced miR-325-3p. Dual-luciferase analysis revealed that miR-325-3p directly targets the 3′UTR of CFL2, thereby suppressing the expression of CFL2, a crucial factor for actin dynamics. Transfection with miR-325-3p mimic resulted in the accumulation of actin filaments (F-actin) and nuclear Yes-associated protein (YAP) in myoblasts and promoted myoblast proliferation and cell cycle progression. Consequently, miR-325-3p mimic significantly attenuated the expressions of myogenic factors and thereby impaired the myogenic differentiation of myoblasts. The roles of miR-325-3p on CFL2 expression, F-actin modulation, and myogenic differentiation suggest a novel miRNA-mediated regulatory mechanism of myogenesis and PA-inducible miR-325-3p may be a critical mediator between obesity and muscle wasting.


2020 ◽  
Vol 40 (12) ◽  
Author(s):  
Michael E. O’Brien ◽  
James Londino ◽  
Marcus McGinnis ◽  
Nathaniel Weathington ◽  
Jessica Adair ◽  
...  

ABSTRACT FBXL2 is an important ubiquitin E3 ligase component that modulates inflammatory signaling and cell cycle progression, but its molecular regulation is largely unknown. Here, we show that tumor necrosis factor alpha (TNF-α), a critical cytokine linked to the inflammatory response during skeletal muscle regeneration, suppressed Fbxl2 mRNA expression in C2C12 myoblasts and triggered significant alterations in cell cycle, metabolic, and protein translation processes. Gene silencing of Fbxl2 in skeletal myoblasts resulted in increased proliferative responses characterized by activation of mitogen-activated protein (MAP) kinases and nuclear factor kappa B and decreased myogenic differentiation, as reflected by reduced expression of myogenin and impaired myotube formation. TNF-α did not destabilize the Fbxl2 transcript (half-life [t1/2], ∼10 h) but inhibited SP1 transactivation of its core promoter, localized to bp −160 to +42 within the proximal 5′ flanking region of the Fbxl2 gene. Chromatin immunoprecipitation and gel shift studies indicated that SP1 interacted with the Fbxl2 promoter during cellular differentiation, an effect that was less pronounced during proliferation or after TNF-α exposure. TNF-α, via activation of JNK, mediated phosphorylation of SP1 that impaired its binding to the Fbxl2 promoter, resulting in reduced transcriptional activity. The results suggest that SP1 transcriptional activation of Fbxl2 is required for skeletal muscle differentiation, a process that is interrupted by a key proinflammatory myopathic cytokine. IMPORTANCE Skeletal muscle regeneration and repair involve the recruitment and proliferation of resident satellite cells that exit the cell cycle during the process of myogenic differentiation to form myofibers. We demonstrate that the ubiquitin E3 ligase subunit FBXL2 is essential for skeletal myogenesis through its important effects on cell cycle progression and cell proliferative signaling. Further, we characterize a new mechanism whereby sustained stimulation by a major proinflammatory cytokine, TNF-α, regulates skeletal myogenesis by inhibiting the interaction of SP1 with the Fbxl2 core promoter in proliferating myoblasts. Our findings contribute to the understanding of skeletal muscle regeneration through the identification of Fbxl2 as both a critical regulator of myogenic proliferative processes and a susceptible gene target during inflammatory stimulation by TNF-α in skeletal muscle. Modulation of Fbxl2 activity may have relevance to disorders of muscle wasting associated with sustained proinflammatory signaling.


Cells ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 332 ◽  
Author(s):  
Kim ◽  
Ahmad ◽  
Shaikh ◽  
Jan ◽  
Seo ◽  
...  

Dermatopontin (DPT) is an extensively distributed non-collagenous component of the extracellular matrix predominantly found in the dermis of the skin, and consequently expressed in several tissues. In this study, we explored the role of DPT in myogenesis and perceived that it enhances the cell adhesion, reduces the cell proliferation and promotes the myoblast differentiation in C2C12 cells. Our results reveal an inhibitory effect with fibronectin (FN) in myoblast differentiation. We also observed that DPT and fibromodulin (FMOD) regulate positively to each other and promote myogenic differentiation. We further predicted the 3D structure of DPT, which is as yet unknown, and validated it using state-of-the-art in silico tools. Furthermore, we explored the in-silico protein-protein interaction between DPT-FMOD, DPT-FN, and FMOD-FN, and perceived that the interaction between FMOD-FN is more robust than DPT-FMOD and DPT-FN. Taken together, our findings have determined the role of DPT at different stages of the myogenic process.


2019 ◽  
Vol 27 (5) ◽  
pp. 1644-1659 ◽  
Author(s):  
Yaping Nie ◽  
Shufang Cai ◽  
Renqiang Yuan ◽  
Suying Ding ◽  
Xumeng Zhang ◽  
...  

Abstract Zinc finger protein 422 (Zfp422) is a widely expressed zinc finger protein that serves as a transcriptional factor to regulate downstream gene expression, but until now, little is known about its roles in myogenesis. We found here that Zfp422 plays a critical role in skeletal muscle development and regeneration. It highly expresses in mouse skeletal muscle during embryonic development. Specific knockout of Zfp422 in skeletal muscle impaired embryonic muscle formation. Satellite cell-specific Zfp422 deletion severely inhibited muscle regeneration. Myoblast differentiation and myotube formation were suppressed in Zfp422-deleted C2C12 cells, isolated primary myoblasts, and satellite cells. Chromatin Immunoprecipitation Sequencing (ChIP-Seq) revealed that Zfp422 regulated ephrin type-A receptor 7 (EphA7) expression by binding an upstream 169-bp DNA sequence, which was proved to be an enhancer of EphA7. Knocking EphA7 down in C2C12 cells or deleting Zfp422 in myoblasts will inhibit cell apoptosis which is required for myoblast differentiation. These results indicate that Zfp422 is essential for skeletal muscle differentiation and fusion, through regulating EphA7 expression to maintain proper apoptosis.


2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Hristina Obradović ◽  
Jelena Krstić ◽  
Tamara Kukolj ◽  
Drenka Trivanović ◽  
Ivana Okić Đorđević ◽  
...  

Interleukin 17 (IL-17) is a cytokine with pleiotropic effects associated with several inflammatory diseases. Although elevated levels of IL-17 have been described in inflammatory myopathies, its role in muscle remodeling and regeneration is still unknown. Excessive extracellular matrix degradation in skeletal muscle is an important pathological consequence of many diseases involving muscle wasting. In this study, the role of IL-17 on the expression of matrix metalloproteinase- (MMP-) 9 in myoblast cells was investigated. The expression of MMP-9 after IL-17 treatment was analyzed in mouse myoblasts C2C12 cell line. The increase in MMP-9 production by IL-17 was concomitant with its capacity to inhibit myogenic differentiation of C2C12 cells. Doxycycline (Doxy) treatment protected the myogenic capacity of myoblasts from IL-17 inhibition and, moreover, increased myotubes hypertrophy. Doxy blocked the capacity of IL-17 to stimulate MMP-9 production by regulating IL-17-induced ERK1/2 MAPK activation. Our results imply that MMP-9 mediates IL-17’s capacity to inhibit myoblast differentiation during inflammatory diseases and indicate that Doxy can modulate myoblast response to inflammatory induction by IL-17.


2007 ◽  
Vol 179 (1) ◽  
pp. 129-138 ◽  
Author(s):  
Luguo Sun ◽  
Kewei Ma ◽  
Haixia Wang ◽  
Fang Xiao ◽  
Yan Gao ◽  
...  

Skeletal muscle stem cell–derived myoblasts are mainly responsible for postnatal muscle growth and injury-induced muscle regeneration. However, the cellular signaling pathways controlling the proliferation and differentiation of myoblasts are not fully understood. We demonstrate that Janus kinase 1 (JAK1) is required for myoblast proliferation and that it also functions as a checkpoint to prevent myoblasts from premature differentiation. Deliberate knockdown of JAK1 in both primary and immortalized myoblasts induces precocious myogenic differentiation with a concomitant reduction in cell proliferation. This is caused, in part, by an accelerated induction of MyoD, myocyte enhancer–binding factor 2 (MEF2), p21Cip1, and p27Kip1, a faster down-regulation of Id1, and an increase in MEF2-dependent gene transcription. Downstream of JAK1, of all the signal transducer and activator of transcriptions (STATs) present in myoblasts, we find that only STAT1 knockdown promotes myogenic differentiation in both primary and immortalized myoblasts. Leukemia inhibitory factor stimulates myoblast proliferation and represses differentiation via JAK1–STAT1–STAT3. Thus, JAK1–STAT1–STAT3 constitutes a signaling pathway that promotes myoblast proliferation and prevents premature myoblast differentiation.


Endocrinology ◽  
2016 ◽  
Vol 157 (1) ◽  
pp. 4-15 ◽  
Author(s):  
Anna Milanesi ◽  
Jang-Won Lee ◽  
Nam-Ho Kim ◽  
Yan-Yun Liu ◽  
An Yang ◽  
...  

Abstract Thyroid hormone plays an essential role in myogenesis, the process required for skeletal muscle development and repair, although the mechanisms have not been established. Skeletal muscle develops from the fusion of precursor myoblasts into myofibers. We have used the C2C12 skeletal muscle myoblast cell line, primary myoblasts, and mouse models of resistance to thyroid hormone (RTH) α and β, to determine the role of thyroid hormone in the regulation of myoblast differentiation. T3, which activates thyroid hormone receptor (TR) α and β, increased myoblast differentiation whereas GC1, a selective TRβ agonist, was minimally effective. Genetic approaches confirmed that TRα plays an important role in normal myoblast proliferation and differentiation and acts through the Wnt/β-catenin signaling pathway. Myoblasts with TRα knockdown, or derived from RTH-TRα PV (a frame-shift mutation) mice, displayed reduced proliferation and myogenic differentiation. Moreover, skeletal muscle from the TRα1PV mutant mouse had impaired in vivo regeneration after injury. RTH-TRβ PV mutant mouse model skeletal muscle and derived primary myoblasts did not have altered proliferation, myogenic differentiation, or response to injury when compared with control. In conclusion, TRα plays an essential role in myoblast homeostasis and provides a potential therapeutic target to enhance skeletal muscle regeneration.


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