The expression levels of two autophagy-related genes, MAP1LC3B and ATG7, and two muscle specific E3 ubiquitin ligases,
atrogin-1 and muscle RING-finger protein-1 (MuRF-1) were assessed using pre-designed primers for each gene (BA055881, MAP1LC3B; BA091910, ATG7; BA048605,
atrogin-1; BA091225, MuRF-1, Takara Bio Inc., Shiga, Japan).
While the exact mechanism underlying glucocorticoid-induced reduction in MM is unclear, augmented muscle protein breakdown via stimulation of the catabolic ubiquitin-proteasome system brought about by increased expression of atrogenes (genes, such as FOXO,
Atrogin-1, and MuRF-1, involved in muscle atrophy) and attenuated muscle protein synthesis via inhibition of anabolic pathways (e.g., mTOR/S6 kinase 1, PBK/Akt, and insulin-like growth factor-l) have been observed (for a review see) (13).
Inflammatory cytokines may lead to the inhibition of skeletal muscle protein synthesis and myoblast differentiation by activating MAFbx/
atrogin-1, eIF3-f, MyoD, and MuRf1 (35-37).
(21) Vibration increased synthesis and decreased activation of the ubiquitin-proteasome pathway with myostatin and
Atrogin-1 suppression, in vitro.
Using RT-PCR, the expression levels of cytokines (IL-6, transforming growth factor [beta] (TGF [beta])), chemokines, and chemokine receptors C-X-C motif chemokine receptor 3 (CXCR3), interferon gamma inducible protein 10 (IP-10), and monocyte chemoattractant protein 1 (MCP-1), and the atrophy-associated gene
atrogin-1 were analyzed.
O TF e um importante regulador de marcadores anabolicos e catabolicos e a pratica regular dessa atividade pode contribuir para a fosforilacao de alguns marcadores anabolicos como a via Akt/mTOR e na cascata de sinalizadores que culminam na sintese proteica como a GSK-3beta, p70S6K e 4E-BP1, alem da inibicao de marcadores catabolicos como Foxo1, Foxo3,
atrogin-1 e MuRF-1 (Leger e colaboradores, 2006; Terzis e colaboradores, 2008).
Simultaneously intense exercise may stimulate the ubiquitin proteasome pathway and the induction of muscle-specific E3-ubiquitin ligases,
atrogin-1 and muscle RING finger-1 (MuRF1) which promote muscle turnover (Rahbek et al., 2015; Stefanetti et al., 2014).
Similarly,
atrogin-1 expression was significantly increased in skeletal muscle at end-stage disease in CBA-administered, SIV-infected macaques (Molina et al.
In IBD, as in chronic inflammatory conditions, a significant reduction in plasma and muscle IGF1 can be seen in response to the elevated concentrations of TNF-alpha and IL-6, cytokines that cause GH resistance in liver and muscles, inducing downregulation of mTOR pathway with activation of ubiquitin ligands and expression of enzymes involved in protein degradation, in particular
atrogin-1, MuRFl, and MUSA1 [39-41].
Methods: TGF-[beta]1 and
atrogin-1 expression was evaluated by RT-qPCR and/or ELISA; Smad3 phosphorylation by western blot; Smad4 nuclear translocation by indirect immunofluorescence; and ROS levels by DCF probe fluorescent measurements.