Advanced glycation end-products induce skeletal muscle atrophy and dysfunction in diabetic mice via a RAGE-mediated, AMPK-down-regulated, Akt pathway
Diabetic myopathy, a less studied complication of diabetes, exhibits the clinical observations characterized by a less muscle mass, muscle weakness and a reduced physical functional capacity. Accumulation of advanced glycation end‐products (AGEs), known to play a role in diabetic complications, has...
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| Published in | The Journal of pathology Vol. 238; no. 3; pp. 470 - 482 |
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| Main Authors | , , , , , , , |
| Format | Journal Article |
| Language | English |
| Published |
Chichester, UK
John Wiley & Sons, Ltd
01.02.2016
Wiley Subscription Services, Inc |
| Subjects | |
| Online Access | Get full text |
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| Summary: | Diabetic myopathy, a less studied complication of diabetes, exhibits the clinical observations characterized by a less muscle mass, muscle weakness and a reduced physical functional capacity. Accumulation of advanced glycation end‐products (AGEs), known to play a role in diabetic complications, has been identified in ageing human skeletal muscles. However, the role of AGEs in diabetic myopathy remains unclear. Here, we investigated the effects of AGEs on myogenic differentiation and muscle atrophy in vivo and in vitro. We also evaluated the therapeutic potential of alagebrium chloride (Ala‐Cl), an inhibitor of AGEs. Muscle fibre atrophy and immunoreactivity for AGEs, Atrogin‐1 (a muscle atrophy marker) and phosphorylated AMP‐activated protein kinase (AMPK) expressions were markedly increased in human skeletal muscles from patients with diabetes as compared with control subjects. Moreover, in diabetic mice we found increased blood AGEs, less muscle mass, lower muscular endurance, atrophic muscle size and poor regenerative capacity, and increased levels of muscle AGE and receptor for AGE (RAGE), Atrogin‐1 and phosphorylated AMPK, which could be significantly ameliorated by Ala‐Cl. Furthermore, in vitro, AGEs (in a dose‐dependent manner) reduced myotube diameters (myotube atrophy) and induced Atrogin‐1 protein expression in myotubes differentiated from both mouse myoblasts and primary human skeletal muscle‐derived progenitor cells. AGEs exerted a negative regulation of myogenesis of mouse and human myoblasts. Ala‐Cl significantly inhibited the effects of AGEs on myotube atrophy and myogenesis. We further demonstrated that AGEs induced muscle atrophy/myogenesis impairment via a RAGE‐mediated AMPK‐down‐regulation of the Akt signalling pathway. Our findings support that AGEs play an important role in diabetic myopathy, and that an inhibitor of AGEs may offer a therapeutic strategy for managing the dysfunction of muscle due to diabetes or ageing. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. |
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| Bibliography: | ark:/67375/WNG-NL5TR69L-7 Figure S1. Quantification of the protein expression of signalling molecules in response to AGEs-induced myotube atrophy. Western blot analysis of the expression of RAGE, p-AMPKα-AMPKα, p-Akt-Akt, Atrogin-1 and p-FoxO1/3a in AGEs (200 µg/ml)-treated C2C12 myotubes in the presence or absence of alagebrium chloride (Ala-Cl; 200 µm), (A, E, F), receptor for AGE-neutralized antibody (RAGE Ab; 10 µg/ml) (B, E, F), insulin-like growth factor-I (IGF-I, an Akt activator; 100 ng/ml) (C, E, F), compound C (an AMPK inhibitor; 1 µm) (D, E, F). All data are presented as mean ± SEM for at least three independent experiments; *p < 0.05 as compared with control group; #p < 0.05 as compared with AGEs aloneFigure S2. Quantification of the protein expression of signalling molecules in response to AGEs-inhibited myogenic differentiation. Western blot analysis of the expression of RAGE, p-AMPKα-AMPKα, p-Akt-Akt, myogenin and MHC in AGEs (25 µg/ml)-treated C2C12 myoblasts during myogenic differentiation in the presence or absence of alagebrium chloride (Ala-Cl; 200 µm) (A), receptor for AGE-neutralized antibody (RAGE Ab; 10 µg/ml) (B), insulin-like growth factor-I (IGF-I, an Akt activator; 100 ng/ml) (C) and compound C (an AMPK inhibitor; 1 µm) (D). All data are presented as mean ± SEM for at least three independent experiments; *p < 0.05 as compared with control group; #p < 0.05 as compared with AGEs aloneFigure S3. Effects of metformin (an AMPK activator) and MK-2206 (an Akt inhibitor), with or without AGEs, in inducing myotube atrophy and inhibiting myogenic differentiation in vitro. In the myotube atrophy experiment, western blot analysis of the expression of p-AMPKα-AMPKα, p-Akt-Akt and Atrogin-1 in AGEs (200 µg/ml)-treated C2C12 myotubes in the presence or absence of metformin (0.5 mm) (A) and MK-2206 (125 nm) (B). In the myogenic differentiation experiment, western blot analysis of the expression of p-AMPKα-AMPKα, p-Akt-Akt, myogenin and MHC in AGEs (25 µg/ml)-treated C2C12 myoblasts during myogenic differentiation in the presence or absence of metformin (0.5 mm) (C) and MK-2206 (125 nm) (D). All data are presented as mean ± SEM for at least three independent experiments; *p < 0.05 as compared with control group; #p < 0.05 as compared with AGEs aloneFigure S4. Quantification of the protein expression of signalling molecules in response to AGE-induced myotube atrophy and AGEs-inhibited myogenic differentiation, with or without metformin and MK-2206. In the myotube atrophy experiment, western blot analysis of the expression of p-AMPKα-AMPKα, p-Akt-Akt and Atrogin-1 in AGEs (200 µg/ml)-treated C2C12 myotubes in the presence or absence of metformin (0.5 mm) (A) and MK-2206 (125 nm) (B). In the myogenic differentiation experiment, western blot analysis of the expression of p-AMPKα-AMPKα, p-Akt-Akt, myogenin and MHC in AGEs (25 µg/ml)-treated C2C12 myoblasts during myogenic differentiation in the presence or absence of metformin (0.5 mm) (C) and MK-2206 (125 nm) (D). All data are presented as mean ± SEM for at least three independent experiments; *p < 0.05 as compared with control group; #p < 0.05 as compared with AGEs alone National Science Council, Taiwan - No. NSC102-2628-B-002-030-MY3 ArticleID:PATH4674 istex:19695D911A20C7ECC4E8F6E58C54B20F1F86D145 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 content type line 23 |
| ISSN: | 0022-3417 1096-9896 1096-9896 |
| DOI: | 10.1002/path.4674 |