ArticlePloS one2022
Initiation of muscle protein synthesis was unrelated to simultaneously upregulated local production of IGF-1 by amino acids in non-proliferating L6 muscle cells.
Article in PloS one, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.
What it found
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The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
6 citing papers in PubMed, 7 citations in OpenAlex.
- Trial
- A randomized translational study on protein- and glucose metabolism in skeletal muscles evaluated by gene-ontology, following preoperative oral carbohydrate loading compared to overnight peripheral parenteral nutrition (PPN) before major cancer surgery.Journal of translational medicine · 2024Trial
- Potential of growth factors and steroid hormones from cell cultures to improveOpen veterinary journal · 2025Review
- Embryonic methionine triggers post-natal developmental programming in Japanese quail.Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2024Article
- Exploring the Integrated Role of miRNAs and lncRNAs in Regulating the Transcriptional Response to Amino Acids and Insulin-like Growth Factor 1 in Gilthead Sea Bream (International journal of molecular sciences · 2024Article
- Expressions of Insulin-like Growth Factor System among Different Breeds Impact Piglets' Growth during Weaning.Animals : an open access journal from MDPI · 2023Article
Corrections and comments
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Authors and funding
3 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundIGF-1 is considered an important regulator of muscle protein synthesis. However, its role in stimulation of muscle protein synthesis by amino acids (AA) is not clear, despite pronounced alterations in IGF-1 mRNA expression and signaling in muscle tissues by feeding. This study evaluates the role of locally produced IGF-1 and IGF-1 signaling when skeletal muscle protein synthesis is activated by increased amino acid availability in confluent, non-proliferating cells.
methodsL6 skeletal muscle cells were subjected to amino acid starvation (24 h, 0.14 mM) followed by 18 h amino acid refeeding in Low AA (0.28 mM) or High AA concentrations (9 mM). Protein synthesis rates were estimated by L-[U-14C]-phenylalanine incorporation into cellular proteins. IGF-1 and IGF-1 receptor mRNA expression were quantified by real time PCR. SiRNA knockdown, antibodies and chemical inhibitors were used to attenuate muscle IGF-1 production and signaling.
resultsHigh AA concentrations (9mM) increased IGF-1 mRNA expression (+ 30%, p<0.05) and increased L-[U-14C]-phenylalanine incorporation compared to Low AA in confluent, non-proliferating muscle cells. Blocking IGF-1 signaling by chemical inhibitors reduced IGF-1 mRNA upregulation (~50%, p< 0.01), without decrease of protein synthesis. SiRNA knockdown of IGF-1 reduced protein synthesis, mainly explained by reduced cell proliferation. High AA or IGF-1 inhibitors did not change IGF-1 receptor mRNA expressions.
conclusionAmino acids increased IGF-1 mRNA expression and stimulated muscle protein synthesis. However, simultaneous upregulation of IGF-1 mRNA did not relate to increased protein synthesis by amino acids. The results indicate that increased IGF-1 mRNA expression is rather a covariate to amino acid initiation of protein synthesis in non-proliferating muscle cells; effects that may be related to unrecognized metabolic activities, such as transport of amino acids.
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