scholarly journals RNASeq Analysis of a Pax3-Expressing Myoblast Clone in-Vitro and Effect of Culture Surface Stiffness on Differentiation

Author(s):  
Louise Richardson ◽  
Dapeng Wang ◽  
Ruth Hughes ◽  
Colin A Johnson ◽  
Michelle Peckham

Abstract Skeletal muscle satellite cells cultured on soft surfaces (12kPa) show improved differentiation than cells cultured on stiff surfaces (approximately 100kPa). To better understand the reasons for this, we performed an RNASeq analysis for a single satellite cell clone (C1F) derived from the H2kb-tsA58 immortomouse, which differentiates into myotubes under tightly regulated conditions (withdrawal of ɣ-interferon, 37°C). As expected, the largest change in overall gene expression occurred at day 1, as cells switch from proliferation to differentiation. Surprisingly, further analysis showed that proliferating C1F cells express Pax3 and not Pax7, confirmed by immunostaining, yet their subsequent differentiation into myotubes is normal, and enhanced on softer surfaces, as evidenced by significantly higher expression levels of myogenic regulatory factors, sarcomeric genes, enhanced fusion and improved myofibrillogenesis. Levels of RNA encoding extracellular matrix structural constituents and related genes were consistently upregulated on hard surfaces, suggesting that a consequence of differentiating satellite cells on hard surfaces is that they attempt to manipulate their niche prior to differentiating. This comprehensive RNASeq dataset will be a useful resource for understanding Pax3 expressing cells.

2021 ◽  
Author(s):  
Louise Richardson ◽  
Dapeng Wang ◽  
Ruth E Hughes ◽  
Colin Anfimov Johnson ◽  
Michelle Peckham

Skeletal muscle satellite cells cultured on soft surfaces (12kPa) show improved differentiation than cells cultured on stiff surfaces (approximately 100kPa). To better understand the reasons for this, we performed an RNA Seq analysis for a single satellite cell clone (C1F) derived from the H2kb-tsA58 immortomouse, which differentiates into myotubes under tightly regulated conditions (withdrawal of γ-interferon, 37°C). As expected, the largest change in overall gene expression occurred at day 1, as cells switch from proliferation to differentiation. Surprisingly, further analysis showed that proliferating C1F cells express Pax3 and not Pax7, confirmed by immunostaining, yet their subsequent differentiation into myotubes is normal, and enhanced on softer surfaces, as evidenced by significantly higher expression levels of myogenic regulatory factors, sarcomeric genes, enhanced fusion and improved myofibrillogenesis. Levels of RNA encoding extracellular matrix structural constituents and related genes were consistently upregulated on hard surfaces, suggesting that a consequence of differentiating satellite cells on hard surfaces is that they attempt to manipulate their niche prior to differentiating. This comprehensive RNASeq dataset will be a useful resource for understanding Pax3 expressing cells.


1995 ◽  
Vol 268 (4) ◽  
pp. H1613-H1620
Author(s):  
C. J. de Groot ◽  
V. A. Chao ◽  
J. M. Roberts ◽  
R. N. Taylor

Human umbilical vein endothelial (HUVE) cells plated on plastic or gelatin-coated dishes grow as a “cobblestone” monolayer. By contrast, endothelial cells cultured on a complex matrix (e.g., Matrigel) form three-dimensional, capillary-like structures. In the current study, we verified the capillary phenotype of the latter structures and asked whether the morphological changes induced by extracellular matrix also affect human endothelial gene expression and function in vitro. Concentrations of cellular fibronectin, prostacyclin, and endothelin-1 were measured in the conditioned media by enzyme-linked immunosorbent and radioimmunoassays. Steady-state concentrations of HUVE mRNA were estimated by reverse transcription-polymerase chain reaction and quantified by Northern analyses to assess fibronectin and endothelin-1 gene expression. We found that the subjacent extracellular matrix affects the morphology, proliferation, and differentiation of HUVE cells in vitro. Cells cultured on gelatin were more mitotically active, expressed significantly less cellular fibronectin, made similar amounts of prostacyclin, and secreted significantly more endothelin-1 compared with the same cells grown on a Matrigel substrate.


2021 ◽  
Vol 49 (2) ◽  
pp. 332-339
Author(s):  
Hideyuki Shirasawa ◽  
Noboru Matsumura ◽  
Masaki Yoda ◽  
Kazumasa Okubo ◽  
Masayuki Shimoda ◽  
...  

Background: The infiltration of fat tissue into skeletal muscle, a condition referred to as muscle fatty infiltration or fatty degeneration, is regarded as an irreversible event that significantly compromises the motor function of skeletal muscle. Purpose: To investigate the effect of retinoic acid receptor (RAR) agonists in suppressing the adipogenic differentiation of fibroadipogenic progenitors (FAPs) in vitro and fatty infiltration after rotator cuff tear in mice. Study Design: Controlled laboratory study. Methods: FAPs isolated from mouse skeletal muscle were cultured in adipogenic differentiation medium in the presence or absence of an RAR agonist. At the end of cell culture, adipogenic differentiation was evaluated by gene expression analysis and oil red O staining. A mouse model of fatty infiltration—which includes the resection of the rotator cuff, removal of the humeral head, and denervation the supraspinatus muscle—was used to induce fatty infiltration in the supraspinatus muscle. The mice were orally or intramuscularly administered with an RAR agonist after the surgery. Muscle fatty infiltration was evaluated by histology and gene expression analysis. Results: RAR agonists effectively inhibited the adipogenic differentiation of FAPs in vitro. Oral and intramuscular administration of RAR agonists suppressed the development of muscle fatty infiltration in the mice after rotator cuff tear. In accordance, we found a significant decrease in the number of intramuscular fat cells and suppressed expression in adipogenic markers. RAR agonists also increased the expression of the transcripts for collagens; however, an accumulation of collagenous tissues was not histologically evident in the present model. Conclusion: Muscle fatty infiltration can be alleviated by RAR agonists through suppressing the adipogenic differentiation of FAPs. The results also suggest that RAR agonists are potential therapeutic agents for treating patients who are at risk of developing muscle fatty infiltration. The consequence of the increased expression of collagen transcripts by RAR agonists needs to be clarified. Clinical Relevance: RAR agonists can be used to prevent the development of muscle fatty infiltration after rotator cuff tear. Nevertheless, further studies are mandatory in a large animal model to examine the safety and efficacy of intramuscular injection of RAR agonists.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tannaz Norizadeh Abbariki ◽  
Zita Gonda ◽  
Denise Kemler ◽  
Pavel Urbanek ◽  
Tabea Wagner ◽  
...  

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.


2014 ◽  
Author(s):  
◽  
Danny A. Stark

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Skeletal muscle can be isolated into 642 individual muscles and makes up to one third to one half of the mass of the human body. Each of these muscles is specified and patterned prenatally and after birth they will increase in size and take on characteristics suited to each muscle's unique function. To make the muscles functional, each muscle cell must be innervated by a motor neuron, which will also affect the characteristics of the mature muscle. In a healthy adult, muscles will maintain their specialized pattern and function during physiological homeostasis, and will also recapitulate them if the integrity or health of the muscle is disrupted. This repair and regeneration is dependent satellite cells, the skeletal muscle stem cells. In this dissertation, we study a family of receptor tyrosine kinases, Ephs, and their juxtacrine ephrin ligands in the context of skeletal muscle specification and regeneration. First, using a classical ephrin 'stripe' assay to test for contact-mediated repulsion, we found that satellite cells respond to a subset of ephrins with repulsive motility in vitro and that these forward signals through Ephs also promote patterning of differentiating myotubes parallel to ephrin stripes. This pattering can be replicated in a heterologous in vivo system (the hindbrain of the developing quail, where neural crest cells migrate in streams to the branchial arches, and in the forelimb of the developing quail, where presumptive limb myoblasts emigrate from the somite). Second, we present evidence that specific pairwise interactions between Eph receptor tyrosine kinases and ephrin ligands are required to ensure appropriate muscle innervation when it is originally set during postnatal development and when it is recapitulated after muscle or nerve trauma during adulthood. We show expression of a single ephrin, ephrin-A3, exclusively on type I (slow) myofibers shortly after birth, while its receptor EphA8 is only localized to fast motor endplates, suggesting a functional repulsive interaction for motor axon guidance and/or synaptogenesis. Adult EFNA3-/- mutant mice show a significant loss of slow myofibers, while misexpression of ephrin-A3 on fast myofibers results in a switch from a fast fiber type to slow in the context of sciatic nerve injury and regrowth. Third, we show that EphA7 is expressed on satellite cell derived myocytes in vitro, and marks both myocytes and regenerating myofibers in vivo. In the EPHA7 knockout mouse, we find a regeneration defect in a barium chloride injury model starting 3 days post injection in vivo, and that cultured mutant satellite cells are slow to differentiate and divide. Finally, we present other potential Ephs and ephrins that may affect skeletal muscle, such as EphB1 that is expressed on all MyHC-IIb fibers and a subset of MyHC-IIx fibers, and we show a multitude of Ephs and ephrins at the neuromuscular junction that appear to localize on specific myofibers and at different areas of the synapse. We propose that Eph/ephrin signaling, though well studied in development, continues to be important in regulating post natal development, regeneration, and homeostasis of skeletal muscle.


Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Karien J Rodriguez ◽  
Kristyn S Masters

Calcification is the leading cause of bioprosthetic and native aortic valve failure, but relatively little is known regarding the factors that contribute to the progression of valvular calcification. Because extracellular matrix (ECM) disarray is often observed in explanted diseased valves, we have investigated the role of individual ECM components in the in vitro calcification of valvular interstitial cells (VICs). The transformation of VICs to an osteoblast-like phenotype was quantified in VICs cultured on different types of ECM coatings. The results show that the number and size of calcific nodules formed in VIC cultures, as well as the expression of mineralization markers alkaline phosphatase (ALP) and CBFa1, were highly dependent upon the composition of the culture surface. In fact, VICs cultured on certain ECM components, namely collagen (Coll) and fibronectin (FN), were resistant to calcification, even upon treatment with potent mineralization-inducing growth factors, such as transforming growth factor beta1 (TGFb1). Meanwhile, VIC cultures on fibrin (FB), laminin, and heparin not only had a high number of calcified nodules (p<0.001 vs. Coll, FN), but also elevated levels of ALP and CBFa1 (p<0.02), and the number of nodules on these ‘pro-calcific’ coatings significantly increased upon treatment with exogenous TGFb1 (p<0.05). To explain the ECM-dependence of calcification, the endogenous production of a pro-mineralization factor (TGFb1) was assessed in VICs on anti-calcific (Coll) and pro-calcific (FB) substrates. Quantification of TGFb1 mRNA revealed that VICs on Coll surfaces expressed a significantly lower amount of TGFb1 mRNA than VICs on FB (p<0.01). Furthermore, treatment with a neutralizing antibody to TGFb1 decreased TGFb1 mRNA expression by VICs on Coll in comparison to VICs on FB or polystyrene controls (p<0.02). Thus, we have discovered a strong correlation between VIC calcification and ECM composition. Our findings show that the ECM plays an important role in controlling TGFb1 expression and subsequent calcification of VICs, which may significantly impact the design of biomaterials for valve tissue engineering, understanding of valvular disease, and the development of preventative treatments for valve calcification.


Alcohol ◽  
2013 ◽  
Vol 47 (7) ◽  
pp. 575
Author(s):  
L. Simon ◽  
N. LeCapitaine ◽  
P. Berner ◽  
T. Dodd ◽  
C. Vande Stouwe ◽  
...  

2018 ◽  
Vol 125 (5) ◽  
pp. 1536-1554 ◽  
Author(s):  
Mette Flindt Heisterberg ◽  
Jesper L. Andersen ◽  
Peter Schjerling ◽  
Alberte Lund ◽  
Simone Dalskov ◽  
...  

Our purpose here was to investigate the potential of blocking the angiotensin II type I receptor (AT1R) on the hypertrophy response of elderly human skeletal muscle to 4 mo of heavy-resistance exercise training. Fifty-eight healthy elderly men (+65 yr) were randomized into three groups, consuming either AT1R blocker (losartan, 100 mg/day) or placebo for 4 mo. Two groups performed resistance training (RT) and were treated with either losartan or placebo, and one group did not train but was treated with losartan. Quadriceps muscle biopsies, MR scans, and strength tests were performed at baseline and after 8 and 16 wk. Biopsies were sectioned for immunohistochemistry to determine the number of satellite cells, capillaries, fiber type distribution, and fiber area. Gene expression levels of myostatin, connective tissue, and myogenic signaling pathways were determined by real-time RT-PCR. Four months of heavy-resistance training led in both training groups to expected improvements in quadriceps (∼3–4%) and vastus lateralis (∼5–6%), cross-sectional area, and type II fiber area (∼10–18%), as well as dynamic (∼13%) and isometric (∼19%) quadriceps peak force, but with absolutely no effect of losartan on these outcomes. Furthermore, no changes were seen in satellite cell number with training, and most gene targets failed to show any changes induced by training or losartan treatment. We conclude that there does not appear to be any effect of AT1R blocking in elderly men during 4 mo of resistance training. Therefore, we do not find any support for using AT1R blockers for promoting muscle adaptation to training in humans. NEW & NOTEWORTHY Animal studies have suggested that blocking angiotensin II type I receptor (AT1R) enhances muscle regeneration and prevents disuse atrophy, but studies in humans are limited. Focusing on hypertrophy, satellite cells, and gene expression, we found that AT1R blocking did not result in any greater responses with 4 mo of resistance training. These results do not support previous findings and question the value of blocking AT1R in the context of preserving aging human muscle.


2018 ◽  
Vol 46 (6) ◽  
pp. 2271-2283 ◽  
Author(s):  
Lianjie Hou ◽  
Jian Xu ◽  
Yiren Jiao ◽  
Huaqin Li ◽  
Zhicheng Pan ◽  
...  

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.


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