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The E3 ubiquitin ligase TRIM62 and inflammation-induced skeletal muscle atrophy.

Schmidt F, Kny M, Zhu X, Wollersheim T, Persicke K, Langhans C, Lodka D, Kleber C, Weber-Carstens S, Fielitz J - Crit Care (2014)

Bottom Line: Trim62 was expressed in myocytes, and its overexpression activated the atrophy-inducing activator protein 1 signal transduction pathway.Knockdown of Trim62 by small interfering RNA inhibited lipopolysaccharide-induced interleukin 6 expression.It could play a role in the pathogenesis of ICUAW by activating and maintaining inflammation in myocytes.

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: ICU-acquired weakness (ICUAW) complicates the disease course of critically ill patients. Inflammation and acute-phase response occur directly within myocytes and contribute to ICUAW. We observed that tripartite motif-containing 62 (TRIM62), an E3 ubiquitin ligase and modifier of inflammation, is increased in the skeletal muscle of ICUAW patients. We investigated the regulation and function of muscular TRIM62 in critical illness.

Methods: Twenty-six critically ill patients with Sequential Organ Failure Assessment scores ≥8 underwent two skeletal muscle biopsies from the vastus lateralis at median days 5 and 15 in the ICU. Four patients undergoing elective orthopedic surgery served as controls. TRIM62 expression and protein content were analyzed in these biopsies. The kinetics of Trim62, Atrogin1 and MuRF1 expression were determined in the gastrocnemius/plantaris and tibialis anterior muscles from mouse models of inflammation-, denervation- and starvation-induced muscle atrophy to differentiate between these contributors to ICUAW. Cultured myocytes were used for mechanistic analyses.

Results: TRIM62 expression and protein content were increased early and remained elevated in muscles from critically ill patients. In all three animal models, muscular Trim62 expression was early and continuously increased. Trim62 was expressed in myocytes, and its overexpression activated the atrophy-inducing activator protein 1 signal transduction pathway. Knockdown of Trim62 by small interfering RNA inhibited lipopolysaccharide-induced interleukin 6 expression.

Conclusions: TRIM62 is activated in the muscles of critically ill patients. It could play a role in the pathogenesis of ICUAW by activating and maintaining inflammation in myocytes.

Trial registration: Current Controlled Trials ID: ISRCTN77569430 (registered 13 February 2008).

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Related in: MedlinePlus

Denervation-induced atrophy. Six- to eight-week-old male C57BL/6 N mice were subjected to surgery. The sciatic nerve of the left hindlimb was dissected (denervated, n =6), and a sham procedure was performed at the right side (innervated, n =6), as indicated. (A) The weights of gastrocnemius/plantaris and tibialis anterior muscles normalized to tibia length were determined at baseline (–) and after 7 days, 14 days and 21 days. Data are presented as mean ± SEM. **P <0.05. Quantitative RT-PCR analyses of Atrogin1(B) and MuRF1(C) expression and immunoblotting of proteins using anti-MuRF1 antibody (D) in gastrocnemius/plantaris and tibialis anterior muscles at 7 days, 14 days and 21 days after surgery, as indicated. Glyceraldehyde 3-phosphate dehydrogenase (Gapdh) expression and protein content were used as reference values, and data shown are the fold changes of the respective innervated sites. Data are presented as mean ± SEM. **P <0.01, *P <0.05. MuRF1, Muscle RING (really interesting new gene) finger–containing protein 1.
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Fig4: Denervation-induced atrophy. Six- to eight-week-old male C57BL/6 N mice were subjected to surgery. The sciatic nerve of the left hindlimb was dissected (denervated, n =6), and a sham procedure was performed at the right side (innervated, n =6), as indicated. (A) The weights of gastrocnemius/plantaris and tibialis anterior muscles normalized to tibia length were determined at baseline (–) and after 7 days, 14 days and 21 days. Data are presented as mean ± SEM. **P <0.05. Quantitative RT-PCR analyses of Atrogin1(B) and MuRF1(C) expression and immunoblotting of proteins using anti-MuRF1 antibody (D) in gastrocnemius/plantaris and tibialis anterior muscles at 7 days, 14 days and 21 days after surgery, as indicated. Glyceraldehyde 3-phosphate dehydrogenase (Gapdh) expression and protein content were used as reference values, and data shown are the fold changes of the respective innervated sites. Data are presented as mean ± SEM. **P <0.01, *P <0.05. MuRF1, Muscle RING (really interesting new gene) finger–containing protein 1.

Mentions: We investigated if Trim62 was regulated in neurogenic muscle atrophy. A progressive loss of muscle weight was observed for gastrocnemius/plantaris and tibialis anterior muscles. Weights of gastrocnemius/plantaris and tibialis anterior muscles were significantly decreased after 7 days of denervation (Figure 4A). A continuous decrease in muscle mass was observed until 21 days of denervation, reaching 54% and 49% (P <0.01 for both) of muscle weight for gastrocnemius/plantaris and tibialis anterior muscles, respectively (Figure 4A). Atrogin1 (Figure 4B) and MuRF1 (Figure 4C) expression was significantly increased at both time points in gastrocnemius/plantaris and tibialis anterior muscles. More specifically, Atrogin1 and MuRF1 expression was highest after 7 days of denervation. Atrogin1 expression was 8.3- and 4.2-fold upregulated in gastrocnemius/plantaris and tibialis anterior muscles, respectively, after 7 days of denervation (P <0.01 for both) (Figure 4B). At the same time point, MuRF1 expression was increased four- and threefold in gastrocnemius/plantaris and tibialis anterior muscles, respectively (P <0.01 for both) (Figure 4C). The MuRF1 protein content showed a comparable time course during denervation in gastrocnemius/plantaris and tibialis anterior muscles (Figure 4D).Figure 4


The E3 ubiquitin ligase TRIM62 and inflammation-induced skeletal muscle atrophy.

Schmidt F, Kny M, Zhu X, Wollersheim T, Persicke K, Langhans C, Lodka D, Kleber C, Weber-Carstens S, Fielitz J - Crit Care (2014)

Denervation-induced atrophy. Six- to eight-week-old male C57BL/6 N mice were subjected to surgery. The sciatic nerve of the left hindlimb was dissected (denervated, n =6), and a sham procedure was performed at the right side (innervated, n =6), as indicated. (A) The weights of gastrocnemius/plantaris and tibialis anterior muscles normalized to tibia length were determined at baseline (–) and after 7 days, 14 days and 21 days. Data are presented as mean ± SEM. **P <0.05. Quantitative RT-PCR analyses of Atrogin1(B) and MuRF1(C) expression and immunoblotting of proteins using anti-MuRF1 antibody (D) in gastrocnemius/plantaris and tibialis anterior muscles at 7 days, 14 days and 21 days after surgery, as indicated. Glyceraldehyde 3-phosphate dehydrogenase (Gapdh) expression and protein content were used as reference values, and data shown are the fold changes of the respective innervated sites. Data are presented as mean ± SEM. **P <0.01, *P <0.05. MuRF1, Muscle RING (really interesting new gene) finger–containing protein 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4231194&req=5

Fig4: Denervation-induced atrophy. Six- to eight-week-old male C57BL/6 N mice were subjected to surgery. The sciatic nerve of the left hindlimb was dissected (denervated, n =6), and a sham procedure was performed at the right side (innervated, n =6), as indicated. (A) The weights of gastrocnemius/plantaris and tibialis anterior muscles normalized to tibia length were determined at baseline (–) and after 7 days, 14 days and 21 days. Data are presented as mean ± SEM. **P <0.05. Quantitative RT-PCR analyses of Atrogin1(B) and MuRF1(C) expression and immunoblotting of proteins using anti-MuRF1 antibody (D) in gastrocnemius/plantaris and tibialis anterior muscles at 7 days, 14 days and 21 days after surgery, as indicated. Glyceraldehyde 3-phosphate dehydrogenase (Gapdh) expression and protein content were used as reference values, and data shown are the fold changes of the respective innervated sites. Data are presented as mean ± SEM. **P <0.01, *P <0.05. MuRF1, Muscle RING (really interesting new gene) finger–containing protein 1.
Mentions: We investigated if Trim62 was regulated in neurogenic muscle atrophy. A progressive loss of muscle weight was observed for gastrocnemius/plantaris and tibialis anterior muscles. Weights of gastrocnemius/plantaris and tibialis anterior muscles were significantly decreased after 7 days of denervation (Figure 4A). A continuous decrease in muscle mass was observed until 21 days of denervation, reaching 54% and 49% (P <0.01 for both) of muscle weight for gastrocnemius/plantaris and tibialis anterior muscles, respectively (Figure 4A). Atrogin1 (Figure 4B) and MuRF1 (Figure 4C) expression was significantly increased at both time points in gastrocnemius/plantaris and tibialis anterior muscles. More specifically, Atrogin1 and MuRF1 expression was highest after 7 days of denervation. Atrogin1 expression was 8.3- and 4.2-fold upregulated in gastrocnemius/plantaris and tibialis anterior muscles, respectively, after 7 days of denervation (P <0.01 for both) (Figure 4B). At the same time point, MuRF1 expression was increased four- and threefold in gastrocnemius/plantaris and tibialis anterior muscles, respectively (P <0.01 for both) (Figure 4C). The MuRF1 protein content showed a comparable time course during denervation in gastrocnemius/plantaris and tibialis anterior muscles (Figure 4D).Figure 4

Bottom Line: Trim62 was expressed in myocytes, and its overexpression activated the atrophy-inducing activator protein 1 signal transduction pathway.Knockdown of Trim62 by small interfering RNA inhibited lipopolysaccharide-induced interleukin 6 expression.It could play a role in the pathogenesis of ICUAW by activating and maintaining inflammation in myocytes.

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: ICU-acquired weakness (ICUAW) complicates the disease course of critically ill patients. Inflammation and acute-phase response occur directly within myocytes and contribute to ICUAW. We observed that tripartite motif-containing 62 (TRIM62), an E3 ubiquitin ligase and modifier of inflammation, is increased in the skeletal muscle of ICUAW patients. We investigated the regulation and function of muscular TRIM62 in critical illness.

Methods: Twenty-six critically ill patients with Sequential Organ Failure Assessment scores ≥8 underwent two skeletal muscle biopsies from the vastus lateralis at median days 5 and 15 in the ICU. Four patients undergoing elective orthopedic surgery served as controls. TRIM62 expression and protein content were analyzed in these biopsies. The kinetics of Trim62, Atrogin1 and MuRF1 expression were determined in the gastrocnemius/plantaris and tibialis anterior muscles from mouse models of inflammation-, denervation- and starvation-induced muscle atrophy to differentiate between these contributors to ICUAW. Cultured myocytes were used for mechanistic analyses.

Results: TRIM62 expression and protein content were increased early and remained elevated in muscles from critically ill patients. In all three animal models, muscular Trim62 expression was early and continuously increased. Trim62 was expressed in myocytes, and its overexpression activated the atrophy-inducing activator protein 1 signal transduction pathway. Knockdown of Trim62 by small interfering RNA inhibited lipopolysaccharide-induced interleukin 6 expression.

Conclusions: TRIM62 is activated in the muscles of critically ill patients. It could play a role in the pathogenesis of ICUAW by activating and maintaining inflammation in myocytes.

Trial registration: Current Controlled Trials ID: ISRCTN77569430 (registered 13 February 2008).

Show MeSH
Related in: MedlinePlus