Mechanisms stimulating muscle wasting in chronic kidney disease: the roles of the ubiquitin-proteasome system and myostatin

Thomas, Sandhya S.

doi:10.1007/s10157-012-0729-9

Cited by 46 publications

(37 citation statements)

References 46 publications

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“…The losses of body and muscle mass were linked to muscle protein degradation in the UPS, because there was an increase in expression of the ubiquitin E3 ligases, Atrogin1 and MuRF1. 15 SGK-1-KO also amplified the expression of these ubiquitin E3 ligases ( Figure 2F). …”

Section: Resultsmentioning

confidence: 86%

Serum Glucocorticoid–Regulated Kinase 1 Blocks CKD–Induced Muscle Wasting Via Inactivation of FoxO3a and Smad2/3

Luo

Liang

et al. 2016

JASN

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Muscle proteolysis in CKD is stimulated when the ubiquitin-proteasome system is activated. Serum glucocorticoid-regulated kinase 1 (SGK-1) is involved in skeletal muscle homeostasis, but the role of this protein in CKDinduced muscle wasting is unknown. We found that, compared with muscles from healthy controls, muscles from patients and mice with CKD express low levels of SGK-1. In mice, SGK-1-knockout (SGK-1-KO) induced muscle loss that correlated with increased expression of ubiquitin E3 ligases known to facilitate protein degradation by the ubiquitin-proteasome, and CKD substantially aggravated this response. SGK-1-KO also altered the phosphorylation levels of transcription factors FoxO3a and Smad2/3. In C2C12 muscle cells, expression of dominant negative FoxO3a or knockdown of Smad2/3 suppressed the upregulation of E3 ligases induced by loss of SGK-1. Additionally, SGK-1 overexpression increased the level of phosphorylated N-myc downstreamregulated gene 1 protein, which directly interacted with and suppressed the phosphorylation of Smad2/3. Overexpression of SGK-1 in wild-type mice with CKD had similar effects on the phosphorylation of FoxO3a and Smad2/3 and prevented CKD-induced muscle atrophy. Finally, mechanical stretch of C2C12 muscle cells or treadmill running of wild-type mice with CKD stimulated SGK-1 production, and treadmill running inhibited proteolysis in muscle. These protective responses were absent in SGK-1-KO mice. Thus, SGK-1 could be a mechanical sensor that mediates exercise-induced improvement in muscle wasting stimulated by CKD. 27: 279727: -280827: , 201627: . doi: 10.1681 CKD is frequently complicated by muscle atrophy because of stimulation of muscle protein degradation mediated by increased activity of both caspase-3 and the ubiquitin-proteasome system (UPS). 1 In muscles of rodents with CKD, caspase-3 stimulates cleavage of the complex structure of muscle protein to provide substrates for degradation by the UPS; it also stimulates proteolytic activity of the 26S proteasome. 2 The UPS can selectively degrade myofibrillar protein by stimulating the expression of ubiquitin E3 ligases, Atrogin1 and MuRF1. These ligases conjugate ubiquitin to proteins targeted for protein degradation, resulting in their degradation in the 26S proteasome. 3 Conditions associated with CKD that initiate loss of muscle mass include metabolic acidosis, inflammation, excess angiotensin II, myostatin expression, and insulin resistance. 1 J Am Soc Nephrol

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Section: Resultsmentioning

confidence: 86%

Serum Glucocorticoid–Regulated Kinase 1 Blocks CKD–Induced Muscle Wasting Via Inactivation of FoxO3a and Smad2/3

Luo

Liang

et al. 2016

JASN

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“…46 Atrogin-1 is robustly upregulated in skeletal muscle in the rodent model of CKD. 47 In this study, atrogin-1 gene expression was upregulated before apparent skeletal muscle wasting, suggesting that the muscle atrophy program begins at an early stage of kidney disease.…”

Section: Discussionmentioning

confidence: 99%

Akt1-Mediated Fast/Glycolytic Skeletal Muscle Growth Attenuates Renal Damage in Experimental Kidney Disease

Hanatani

Izumiya

Araki

et al. 2014

Journal of the American Society of Nephrology

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Muscle wasting is frequently observed in patients with kidney disease, and low muscle strength is associated with poor outcomes in these patients. However, little is known about the effects of skeletal muscle growth per se on kidney diseases. In this study, we utilized a skeletal muscle-specific, inducible Akt1 transgenic (Akt1 TG) mouse model that promotes the growth of functional skeletal muscle independent of exercise to investigate the effects of muscle growth on kidney diseases. Seven days after Akt1 activation in skeletal muscle, renal injury was induced by unilateral ureteral obstruction (UUO) in Akt1 TG and wild-type (WT) control mice. The expression of atrogin-1, an atrophy-inducing gene in skeletal muscle, was upregulated 7 days after UUO in WT mice but not in Akt1 TG mice. UUO-induced renal interstitial fibrosis, tubular injury, apoptosis, and increased expression of inflammatory, fibrosis-related, and adhesion molecule genes were significantly diminished in Akt1 TG mice compared with WT mice. An increase in the activating phosphorylation of eNOS in the kidney accompanied the attenuation of renal damage by myogenic Akt1 activation. Treatment with the NOS inhibitor L-NAME abolished the protective effect of skeletal muscle Akt activation on obstructive kidney disease. In conclusion, Akt1-mediated muscle growth reduces renal damage in a model of obstructive kidney disease. This improvement appears to be mediated by an increase in eNOS signaling in the kidney. Our data support the concept that loss of muscle mass during kidney disease can contribute to renal failure, and maintaining muscle mass may improve clinical outcome.

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“…Metabolic acidosis potentially accelerates proteolysis and amino acid catabolism, probably through activation of caspase-3 and the ubiquitin proteasome system or via effects on the growth hormone/IGF-1 axis (97,(182)(183)(184)(185)(186) .…”

Section: Dietary Acid-base Loadmentioning

confidence: 99%

Nutritional influences on age-related skeletal muscle loss

2013

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Age-related muscle loss impacts on whole-body metabolism and leads to frailty and sarcopenia, which are risk factors for fractures and mortality. Although nutrients are integral to muscle metabolism the relationship between nutrition and muscle loss has only been extensively investigated for protein and amino acids. The objective of the present paper is to describe other aspects of nutrition and their association with skeletal muscle mass. Mechanisms for muscle loss relate to imbalance in protein turnover with a number of anabolic pathways of which the mechanistic TOR pathway and the IGF-1-Akt-FoxO pathways are the most characterised.

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Mechanisms stimulating muscle wasting in chronic kidney disease: the roles of the ubiquitin-proteasome system and myostatin

Cited by 46 publications

References 46 publications

Serum Glucocorticoid–Regulated Kinase 1 Blocks CKD–Induced Muscle Wasting Via Inactivation of FoxO3a and Smad2/3

Serum Glucocorticoid–Regulated Kinase 1 Blocks CKD–Induced Muscle Wasting Via Inactivation of FoxO3a and Smad2/3

Akt1-Mediated Fast/Glycolytic Skeletal Muscle Growth Attenuates Renal Damage in Experimental Kidney Disease

Nutritional influences on age-related skeletal muscle loss

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