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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

Starvation leads to skeletal muscle atrophyin vivo. Six- to eight-week-old male C57BL/6 N mice were subjected to food deprivation for 24 hours (n =6) or 48 hours (n =6), as indicated. Mice fed standard chow (controls, –; n =6) were used as controls. (A) Weights of gastrocnemius/plantaris and tibialis anterior muscles normalized to tibia length are shown. Data are presented as mean ± SEM. ***P <0.001, **P <0.01. 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 of control animals (–) and mice deprived of food for 24 hours and 48 hours are shown, as indicated. Glyceraldehyde 3-phosphate dehydrogenase (Gapdh) expression and protein content were used as reference values, and data shown are fold changes compared to controls. 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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Fig5: Starvation leads to skeletal muscle atrophyin vivo. Six- to eight-week-old male C57BL/6 N mice were subjected to food deprivation for 24 hours (n =6) or 48 hours (n =6), as indicated. Mice fed standard chow (controls, –; n =6) were used as controls. (A) Weights of gastrocnemius/plantaris and tibialis anterior muscles normalized to tibia length are shown. Data are presented as mean ± SEM. ***P <0.001, **P <0.01. 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 of control animals (–) and mice deprived of food for 24 hours and 48 hours are shown, as indicated. Glyceraldehyde 3-phosphate dehydrogenase (Gapdh) expression and protein content were used as reference values, and data shown are fold changes compared to controls. Data are presented as mean ± SEM. **P <0.01, *P <0.05. MuRF1, Muscle RING (really interesting new gene) finger–containing protein 1.

Mentions: To investigate the impact of starvation on muscle atrophy, mice were food-deprived for 24 hours and 48 hours. Food deprivation led to decreases in body weight (14% after 24 hours (P <0.01) and 20% after 48 hours (P <0.01)) (Additional file 4: Figure S3B). Following food deprivation, a reduction in muscle weight was found for the gastrocnemius/plantaris muscles (15% after 48 hours (P <0.001) of starvation), but not tibialis anterior muscle (Figure 5A). qRT-PCR experiments showed an upregulation of muscular Atrogin1 and MuRF1 expression during starvation (Figures 5B and 5C). Atrogin1 expression increased 21.6-fold and 29.4-fold after 24 hours and 48 hours of starvation, respectively, in gastrocnemius/plantaris muscles (P <0.01 for both). Atrogin1 expression was also increased in tibialis anterior muscle (Figure 5B). In gastrocnemius/plantaris muscles, MuRF1 expression increased 21-fold and 24-fold after 24 hours and 48 hours of starvation, respectively (P <0.01 for both). MuRF1 expression was also increased in tibialis anterior muscle (Figure 5C). The MuRF1 protein content was increased in gastrocnemius/plantaris and tibialis anterior muscles of mice subjected to starvation (Figure 5D).Figure 5


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)

Starvation leads to skeletal muscle atrophyin vivo. Six- to eight-week-old male C57BL/6 N mice were subjected to food deprivation for 24 hours (n =6) or 48 hours (n =6), as indicated. Mice fed standard chow (controls, –; n =6) were used as controls. (A) Weights of gastrocnemius/plantaris and tibialis anterior muscles normalized to tibia length are shown. Data are presented as mean ± SEM. ***P <0.001, **P <0.01. 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 of control animals (–) and mice deprived of food for 24 hours and 48 hours are shown, as indicated. Glyceraldehyde 3-phosphate dehydrogenase (Gapdh) expression and protein content were used as reference values, and data shown are fold changes compared to controls. 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

Fig5: Starvation leads to skeletal muscle atrophyin vivo. Six- to eight-week-old male C57BL/6 N mice were subjected to food deprivation for 24 hours (n =6) or 48 hours (n =6), as indicated. Mice fed standard chow (controls, –; n =6) were used as controls. (A) Weights of gastrocnemius/plantaris and tibialis anterior muscles normalized to tibia length are shown. Data are presented as mean ± SEM. ***P <0.001, **P <0.01. 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 of control animals (–) and mice deprived of food for 24 hours and 48 hours are shown, as indicated. Glyceraldehyde 3-phosphate dehydrogenase (Gapdh) expression and protein content were used as reference values, and data shown are fold changes compared to controls. Data are presented as mean ± SEM. **P <0.01, *P <0.05. MuRF1, Muscle RING (really interesting new gene) finger–containing protein 1.
Mentions: To investigate the impact of starvation on muscle atrophy, mice were food-deprived for 24 hours and 48 hours. Food deprivation led to decreases in body weight (14% after 24 hours (P <0.01) and 20% after 48 hours (P <0.01)) (Additional file 4: Figure S3B). Following food deprivation, a reduction in muscle weight was found for the gastrocnemius/plantaris muscles (15% after 48 hours (P <0.001) of starvation), but not tibialis anterior muscle (Figure 5A). qRT-PCR experiments showed an upregulation of muscular Atrogin1 and MuRF1 expression during starvation (Figures 5B and 5C). Atrogin1 expression increased 21.6-fold and 29.4-fold after 24 hours and 48 hours of starvation, respectively, in gastrocnemius/plantaris muscles (P <0.01 for both). Atrogin1 expression was also increased in tibialis anterior muscle (Figure 5B). In gastrocnemius/plantaris muscles, MuRF1 expression increased 21-fold and 24-fold after 24 hours and 48 hours of starvation, respectively (P <0.01 for both). MuRF1 expression was also increased in tibialis anterior muscle (Figure 5C). The MuRF1 protein content was increased in gastrocnemius/plantaris and tibialis anterior muscles of mice subjected to starvation (Figure 5D).Figure 5

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