The Experts below are selected from a list of 53439 Experts worldwide ranked by ideXlab platform
Hans Bloemendal - One of the best experts on this subject based on the ideXlab platform.
-
Characteristics of super αA-crystallin, a product of in vitro exon shuffling
FEBS Letters, 2000Co-Authors: Anke Van Rijk, Wilfried W. De Jong, Maarten J.j. Van Den Hurk, Wouter Renkema, Wilbert C. Boelens, Hans BloemendalAbstract:αA-Crystallin, a small heat shock protein with chaperone-like activity, forms dynamic multimeric complexes. Recently we described the spontaneous generation of a mutant protein (super αA-crystallin) by exon duplication arisen via exon shuffling confirming a classic hypothesis by Gilbert [Nature 271 (1978) 501]. Comparison of super αA-crystallin, which is viable in a mouse Skeletal Muscle Cell line, with normal αA-crystallin shows that it has diminished thermostability, increased exposure of hydrophobic patches, a larger complex size and lost its chaperone activity. However, super αA-crystallin subunits exchange as readily between complexes as does normal αA-crystallin. These data indicate that chaperone-like activity may vanish independent of subunit hydrophobicity and exchangeability.
-
Characteristics of super alphaA-crystallin, a product of in vitro exon shuffling.
FEBS letters, 2000Co-Authors: Anke Van Rijk, Wilfried W. De Jong, Maarten J.j. Van Den Hurk, Wouter Renkema, Wilbert C. Boelens, Hans BloemendalAbstract:alphaA-Crystallin, a small heat shock protein with chaperone-like activity, forms dynamic multimeric complexes. Recently we described the spontaneous generation of a mutant protein (super alphaA-crystallin) by exon duplication arisen via exon shuffling confirming a classic hypothesis by Gilbert [Nature 271 (1978) 501]. Comparison of super alphaA-crystallin, which is viable in a mouse Skeletal Muscle Cell line, with normal alphaA-crystallin shows that it has diminished thermostability, increased exposure of hydrophobic patches, a larger complex size and lost its chaperone activity. However, super alphaA-crystallin subunits exchange as readily between complexes as does normal alphaA-crystallin. These data indicate that chaperone-like activity may vanish independent of subunit hydrophobicity and exchangeability.
Anke Van Rijk - One of the best experts on this subject based on the ideXlab platform.
-
Characteristics of super αA-crystallin, a product of in vitro exon shuffling
FEBS Letters, 2000Co-Authors: Anke Van Rijk, Wilfried W. De Jong, Maarten J.j. Van Den Hurk, Wouter Renkema, Wilbert C. Boelens, Hans BloemendalAbstract:αA-Crystallin, a small heat shock protein with chaperone-like activity, forms dynamic multimeric complexes. Recently we described the spontaneous generation of a mutant protein (super αA-crystallin) by exon duplication arisen via exon shuffling confirming a classic hypothesis by Gilbert [Nature 271 (1978) 501]. Comparison of super αA-crystallin, which is viable in a mouse Skeletal Muscle Cell line, with normal αA-crystallin shows that it has diminished thermostability, increased exposure of hydrophobic patches, a larger complex size and lost its chaperone activity. However, super αA-crystallin subunits exchange as readily between complexes as does normal αA-crystallin. These data indicate that chaperone-like activity may vanish independent of subunit hydrophobicity and exchangeability.
-
Characteristics of super alphaA-crystallin, a product of in vitro exon shuffling.
FEBS letters, 2000Co-Authors: Anke Van Rijk, Wilfried W. De Jong, Maarten J.j. Van Den Hurk, Wouter Renkema, Wilbert C. Boelens, Hans BloemendalAbstract:alphaA-Crystallin, a small heat shock protein with chaperone-like activity, forms dynamic multimeric complexes. Recently we described the spontaneous generation of a mutant protein (super alphaA-crystallin) by exon duplication arisen via exon shuffling confirming a classic hypothesis by Gilbert [Nature 271 (1978) 501]. Comparison of super alphaA-crystallin, which is viable in a mouse Skeletal Muscle Cell line, with normal alphaA-crystallin shows that it has diminished thermostability, increased exposure of hydrophobic patches, a larger complex size and lost its chaperone activity. However, super alphaA-crystallin subunits exchange as readily between complexes as does normal alphaA-crystallin. These data indicate that chaperone-like activity may vanish independent of subunit hydrophobicity and exchangeability.
Mario Pende - One of the best experts on this subject based on the ideXlab platform.
-
Important role for AMPKalpha1 in limiting Skeletal Muscle Cell hypertrophy.
FASEB Journal, 2009Co-Authors: Rémi Mounier, Louise Lantier, Jocelyne Leclerc, Athanassia Sotiropoulos, Mario Pende, Dominique Daegelen, Kei Sakamoto, Marc Foretz, Benoit ViolletAbstract:Activation of AMP-activated protein kinase (AMPK) inhibits protein synthesis through the suppression of the mammalian target of rapamycin complex 1 (mTORC1), a critical regulator of Muscle growth. The purpose of this investigation was to determine the role of the AMPKalpha1 catalytic subunit on Muscle Cell size control and adaptation to Muscle hypertrophy. We found that AMPKalpha1(-/-) primary cultured myotubes and myofibers exhibit larger Cell size compared with control Cells in response to chronic Akt activation. We next subjected the plantaris Muscle of AMPKalpha1(-/-) and control mice to mechanical overloading to induce Muscle hypertrophy. We observed significant elevations of AMPKalpha1 activity in the control Muscle at days 7 and 21 after the overload. Overloading-induced Muscle hypertrophy was significantly accelerated in AMPKalpha1(-/-) mice than in control mice [+32 vs. +53% at day 7 and +57 vs. +76% at day 21 in control vs. AMPKalpha1(-/-) mice, respectively]. This enhanced growth of AMPKalpha1-deficient Muscle was accompanied by increased phosphorylation of mTOR signaling downstream targets and decreased phosphorylation of eukaryotic elongation factor 2. These results demonstrate that AMPKalpha1 plays an important role in limiting Skeletal Muscle overgrowth during hypertrophy through inhibition of the mTOR-signaling pathway.
-
growth hormone promotes Skeletal Muscle Cell fusion independent of insulin like growth factor 1 up regulation
Proceedings of the National Academy of Sciences of the United States of America, 2006Co-Authors: Athanassia Sotiropoulos, Mickael Ohanna, Cecile Kedzia, Ram K Menon, John J Kopchick, Paul A Kelly, Mario PendeAbstract:Growth hormone (GH) participates in the postnatal regulation of Skeletal Muscle growth, although the mechanism of action is unclear. Here we show that the mass of Skeletal Muscles lacking GH receptors is reduced because of a decrease in myofiber size with normal myofiber number. GH signaling controls the size of the differentiated myotubes in a Cell-autonomous manner while having no effect on size, proliferation, and differentiation of the myoblast precursor Cells. The GH hypertrophic action leads to an increased myonuclear number, indicating that GH facilitates fusion of myoblasts with nascent myotubes. NFATc2, a transcription factor regulating this phase of fusion, is required for GH action because GH is unable to induce hypertrophy of NFATc2−/− myotubes. Finally, we provide three lines of evidence suggesting that GH facilitates Cell fusion independent of insulin-like growth factor 1 (IGF-1) up-regulation. First, GH does not regulate IGF-1 expression in myotubes; second, GH action is not mediated by a secreted factor in conditioned medium; third, GH and IGF-1 hypertrophic effects are additive and rely on different signaling pathways. Taken together, these data unravel a specific function of GH in the control of Cell fusion, an essential process for Muscle growth.
Anna Polesskaya - One of the best experts on this subject based on the ideXlab platform.
-
Post-transcriptional modulation of interleukin 8 by CNOT6L regulates Skeletal Muscle differentiation
Biochimica et Biophysica Acta - Molecular Cell Research, 2016Co-Authors: Anna Polesskaya, Guillaume Pinna, Yassine Sassi, Marie Vandamme, Anne Bigot, Vincent Mouly, Nadya Morozova, Annick Harel-bellan, Cindy DegernyAbstract:CNOT6L is a deadenylase subunit belonging to the CCR4-NOT complex, a major deadenylase complex in eukaryotes involved at multiple levels in regulation of gene expression. While CNOT6L is expressed in Skeletal Muscle Cells, its specific functions in this tissue are still largely unknown. Our previous work highlighted the functional of CNOT6L in Skeletal Muscle Cell differentiation. To further explore how CNOT6L regulates myogenesis, we used here gene expression analysis to identify CNOT6L mRNA targets in human myoblasts. Among these novel targets, IL-8 (interleukin 8) mRNA was the most upregulated in CNOT6L knock-down (KD) Cells. Biochemical approaches and poly (A) tail length assays showed that IL-8 mRNA is a direct target of CNOT6L, and further investigations by loss- and gain-of-function assays pointed out that IL-8 is an important effector of myogenesis. Therefore, we have characterized CNOT6L-IL-8 as a new signaling axis that regulates myogenesis.
-
TNF-α and IGF1 modify the microRNA signature in Skeletal Muscle Cell differentiation
Cell Communication and Signaling, 2015Co-Authors: Swanhild U Meyer, Christian Thirion, Anna Polesskaya, Stefan Bauersachs, Sebastian Kaiser, Sabine Krause, Michael W PfafflAbstract:Background Elevated levels of the inflammatory cytokine TNF-α are common in chronic diseases or inherited or degenerative Muscle disorders and can lead to Muscle wasting. By contrast, IGF1 has a growth promoting effect on Skeletal Muscle. The molecular mechanisms mediating the effect of TNF-α and IGF1 on Muscle Cell differentiation are not completely understood. Muscle Cell proliferation and differentiation are regulated by microRNAs (miRNAs) which play a dominant role in this process. This study aims at elucidating how TNF-α or IGF1 regulate microRNA expression to affect myoblast differentiation and myotube formation. Results In this study, we analyzed the impact of TNF-α or IGF1 treatment on miRNA expression in myogenic Cells. Results reveal that i) TNF-α and IGF1 regulate miRNA expression during Skeletal Muscle Cell differentiation in vitro , ii) microRNA targets can mediate the negative effect of TNF-α on fusion capacity of Skeletal myoblasts by targeting genes associated with axon guidance, MAPK signalling, focal adhesion, and neurotrophin signalling pathway, iii) inhibition of miR-155 in combination with overexpression of miR-503 partially abrogates the inhibitory effect of TNF-α on myotube formation, and iv) MAPK/ERK inhibition might participate in modulating the effect of TNF-α and IGF1 on miRNA abundance. Conclusions The inhibitory effects of TNF-α or the growth promoting effects of IGF1 on Skeletal Muscle differentiation include the deregulation of known Muscle-regulatory miRNAs as well as miRNAs which have not yet been associated with Skeletal Muscle differentiation or response to TNF-α or IGF1. This study indicates that miRNAs are mediators of the inhibitory effect of TNF-α on myoblast differentiation. We show that intervention at the miRNA level can ameliorate the negative effect of TNF-α by promoting myoblast differentiation. Moreover, we cautiously suggest that TNF-α or IGF1 modulate the miRNA biogenesis of some miRNAs via MAPK/ERK signalling. Finally, this study identifies indicative biomarkers of myoblast differentiation and cytokine influence and points to novel RNA targets.
-
TNF-α and IGF1 modify the microRNA signature in Skeletal Muscle Cell differentiation.
Cell Communication and Signaling, 2015Co-Authors: Swanhild U Meyer, Christian Thirion, Anna Polesskaya, Stefan Bauersachs, Sebastian Kaiser, Sabine Krause, Michael W PfafflAbstract:Elevated levels of the inflammatory cytokine TNF-α are common in chronic diseases or inherited or degenerative Muscle disorders and can lead to Muscle wasting. By contrast, IGF1 has a growth promoting effect on Skeletal Muscle. The molecular mechanisms mediating the effect of TNF-α and IGF1 on Muscle Cell differentiation are not completely understood. Muscle Cell proliferation and differentiation are regulated by microRNAs (miRNAs) which play a dominant role in this process. This study aims at elucidating how TNF-α or IGF1 regulate microRNA expression to affect myoblast differentiation and myotube formation.
-
The microRNA miR-181 targets the homeobox protein Hox-A11 during mammalian myoblast differentiation.
Nature Cell Biology, 2006Co-Authors: Irina Naguibneva, Anna Polesskaya, Maya Ameyar-zazoua, Slimane Ait-si-ali, Reguina Groisman, Mouloud Souidi, Sylvain Cuvellier, Annick Harel-bellanAbstract:Deciphering the mechanisms underlying Skeletal Muscle-Cell differentiation in mammals is an important challenge. Cell differentiation involves complex pathways regulated at both transcriptional and post-transcriptional levels. Recent observations have revealed the importance of small (20-25 base pair) non-coding RNAs (microRNAs or miRNAs) that are expressed in both lower organisms and in mammals. miRNAs modulate gene expression by affecting mRNA translation or stability. In lower organisms, miRNAs are essential for Cell differentiation during development; some miRNAs are involved in maintenance of the differentiated state. Here, we show that miR-181, a microRNA that is strongly upregulated during differentiation, participates in establishing the Muscle phenotype. Moreover, our results suggest that miR-181 downregulates the homeobox protein Hox-A11 (a repressor of the differentiation process), thus establishing a functional link between miR-181 and the complex process of mammalian Skeletal-Muscle differentiation. Therefore, miRNAs can be involved in the establishment of a differentiated phenotype - even when they are not expressed in the corresponding fully differentiated tissue.
Michael W Pfaffl - One of the best experts on this subject based on the ideXlab platform.
-
TNF-α and IGF1 modify the microRNA signature in Skeletal Muscle Cell differentiation
Cell Communication and Signaling, 2015Co-Authors: Swanhild U Meyer, Christian Thirion, Anna Polesskaya, Stefan Bauersachs, Sebastian Kaiser, Sabine Krause, Michael W PfafflAbstract:Background Elevated levels of the inflammatory cytokine TNF-α are common in chronic diseases or inherited or degenerative Muscle disorders and can lead to Muscle wasting. By contrast, IGF1 has a growth promoting effect on Skeletal Muscle. The molecular mechanisms mediating the effect of TNF-α and IGF1 on Muscle Cell differentiation are not completely understood. Muscle Cell proliferation and differentiation are regulated by microRNAs (miRNAs) which play a dominant role in this process. This study aims at elucidating how TNF-α or IGF1 regulate microRNA expression to affect myoblast differentiation and myotube formation. Results In this study, we analyzed the impact of TNF-α or IGF1 treatment on miRNA expression in myogenic Cells. Results reveal that i) TNF-α and IGF1 regulate miRNA expression during Skeletal Muscle Cell differentiation in vitro , ii) microRNA targets can mediate the negative effect of TNF-α on fusion capacity of Skeletal myoblasts by targeting genes associated with axon guidance, MAPK signalling, focal adhesion, and neurotrophin signalling pathway, iii) inhibition of miR-155 in combination with overexpression of miR-503 partially abrogates the inhibitory effect of TNF-α on myotube formation, and iv) MAPK/ERK inhibition might participate in modulating the effect of TNF-α and IGF1 on miRNA abundance. Conclusions The inhibitory effects of TNF-α or the growth promoting effects of IGF1 on Skeletal Muscle differentiation include the deregulation of known Muscle-regulatory miRNAs as well as miRNAs which have not yet been associated with Skeletal Muscle differentiation or response to TNF-α or IGF1. This study indicates that miRNAs are mediators of the inhibitory effect of TNF-α on myoblast differentiation. We show that intervention at the miRNA level can ameliorate the negative effect of TNF-α by promoting myoblast differentiation. Moreover, we cautiously suggest that TNF-α or IGF1 modulate the miRNA biogenesis of some miRNAs via MAPK/ERK signalling. Finally, this study identifies indicative biomarkers of myoblast differentiation and cytokine influence and points to novel RNA targets.
-
TNF-α and IGF1 modify the microRNA signature in Skeletal Muscle Cell differentiation.
Cell Communication and Signaling, 2015Co-Authors: Swanhild U Meyer, Christian Thirion, Anna Polesskaya, Stefan Bauersachs, Sebastian Kaiser, Sabine Krause, Michael W PfafflAbstract:Elevated levels of the inflammatory cytokine TNF-α are common in chronic diseases or inherited or degenerative Muscle disorders and can lead to Muscle wasting. By contrast, IGF1 has a growth promoting effect on Skeletal Muscle. The molecular mechanisms mediating the effect of TNF-α and IGF1 on Muscle Cell differentiation are not completely understood. Muscle Cell proliferation and differentiation are regulated by microRNAs (miRNAs) which play a dominant role in this process. This study aims at elucidating how TNF-α or IGF1 regulate microRNA expression to affect myoblast differentiation and myotube formation.