Calpain and caspase-3 play required roles in immobilization-induced limb muscle atrophy

Prolonged skeletal muscle inactivity results in a rapid decrease in fiber size, primarily due to accelerated proteolysis. Although several proteases are known to contribute to disuse muscle atrophy, the ubiquitin proteasome system is often considered the most important proteolytic system during many conditions that promote muscle wasting. Emerging evidence suggests that calpain and caspase-3 may also play key roles in inactivity-induced atrophy of respiratory muscles, but it remains unknown if these proteases are essential for disuse atrophy in limb skeletal muscles. Therefore, we tested the hypothesis that activation of both calpain and caspase-3 is required for locomotor muscle atrophy induced by hindlimb immobilization. Seven days of immobilization (i.e., limb casting) promoted significant atrophy in type I muscle fibers of the rat soleus muscle. Independent pharmacological inhibition of calpain or caspase-3 prevented this casting-induced atrophy. Interestingly, inhibition of calpain activity also prevented caspase-3 activation, and, conversely, inhibition of caspase-3 prevented calpain activation. These findings indicate that a regulatory cross talk exists between these proteases and provide the first evidence that the activation of calpain and caspase-3 is required for inactivity-induced limb muscle atrophy.

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Supplementation of ketoacids contributes to the up-regulation of the Wnt7a/Akt/p70S6K pathway and the down-regulation of apoptotic and ubiquitin–proteasome systems in the muscle of 5/6 nephrectomised rats

British Journal Of Nutrition ◽

10.1017/s0007114513004091 ◽

2014 ◽

Vol 111 (9) ◽

pp. 1536-1548 ◽

Cited By ~ 25

Author(s):

Dong-Tao Wang ◽

Lu Lu ◽

Ying Shi ◽

Zhen-Bo Geng ◽

Yi Yin ◽

...

Keyword(s):

Muscle Mass ◽

Muscle Atrophy ◽

Caspase 3 ◽

Ring Finger ◽

Ubiquitin Proteasome System ◽

Protein Diet ◽

Down Regulation ◽

Beneficial Effects ◽

Phosphorylated Akt ◽

Ubiquitin Proteasome

Ketoacids (KA) are known to improve muscle mass among patients with chronic kidney disease (CKD) on a low-protein diet (CKD-LPD), but the mechanism of its preventive effects on muscle atrophy still remains unclear. Since muscle atrophy in CKD may be attributable to the down-regulation of the Wnt7a/Akt/p70S6K pathway and the activation of the ubiquitin–proteasome system (UPS) and the apoptotic signalling pathway, a hypothesis can readily be drawn that KA supplementation improves muscle mass by up-regulating the Wnt7a/Akt/p70S6K pathway and counteracting the activation of the UPS and caspase-3-dependent apoptosis in the muscle of CKD-LPD rats. Rats with 5/6 nephrectomy were randomly divided into three groups, and fed with either 22 % protein (normal-protein diet; NPD), 6 % protein (LPD) or 5 % protein plus 1 % KA for 24 weeks. Sham-operated rats with NPD intake were used as the control. The results demonstrated that KA supplementation improved protein synthesis and increased related mediators such as Wnt7a, phosphorylated Akt and p70S6K in the muscle of CKD-LPD rats. It also inhibited protein degradation, withheld the increase in ubiquitin and its ligases MAFbx (muscle atrophy F-box) and MuRF1 (muscle ring finger-1) as well as attenuated proteasome activity in the muscle of CKD-LPD rats. Moreover, KA supplementation gave rise to a reduction in DNA fragment, cleaved caspase-3 and 14 kDa actin fragment via the down-regulation of the Bax:Bcl-2 ratio in the muscle of CKD-LPD rats. The beneficial effects unveiled herein further consolidate that KA may be a better therapeutic strategy for muscle atrophy in CKD-LPD.

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Identification of the MuRF1 skeletal muscle ubiquitylome through quantitative proteomics

Function ◽

10.1093/function/zqab029 ◽

2021 ◽

Author(s):

Leslie M Baehr ◽

David C Hughes ◽

Sarah A Lynch ◽

Delphi Van Haver ◽

Teresa Mendes Maia ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Atrophy ◽

Potential Role ◽

Ubiquitin Proteasome System ◽

In Vivo Electroporation ◽

Adult Mice ◽

Expression Of Genes ◽

Regulation Of Metabolism ◽

Ubiquitin Proteasome

Abstract MuRF1 (TRIM63) is a muscle-specific E3 ubiquitin ligase and component of the ubiquitin proteasome system. MuRF1 is transcriptionally upregulated under conditions that cause muscle loss, in both rodents and humans, and is a recognized marker of muscle atrophy. In this study, we used in vivo electroporation to determine if MuRF1 overexpression alone can cause muscle atrophy and, in combination with ubiquitin proteomics, identify the endogenous MuRF1 substrates in skeletal muscle. Overexpression of MuRF1 in adult mice increases ubiquitination of myofibrillar and sarcoplasmic proteins, increases expression of genes associated with neuromuscular junction instability, and causes muscle atrophy. A total of 169 ubiquitination sites on 56 proteins were found to be regulated by MuRF1. MuRF1-mediated ubiquitination targeted both thick and thin filament contractile proteins, as well as, glycolytic enzymes, deubiquitinases, p62, and VCP. These data reveal a potential role for MuRF1 in not only the breakdown of the sarcomere, but also the regulation of metabolism and other proteolytic pathways in skeletal muscle.

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Increasing autophagy does not affect neurogenic muscle atrophy

European Journal of Translational Myology ◽

10.4081/ejtm.2018.7687 ◽

2018 ◽

Vol 28 (3) ◽

Cited By ~ 5

Author(s):

Eva Pigna ◽

Krizia Sanna ◽

Dario Coletti ◽

Zhenlin Li ◽

Ara Parlakian ◽

...

Keyword(s):

Muscle Mass ◽

Muscle Atrophy ◽

Ubiquitin Proteasome System ◽

Autophagic Flux ◽

Molecular Pathways ◽

Muscle Loss ◽

Relative Contribution ◽

Ubiquitin Proteasome ◽

Muscle Mass Loss ◽

Kinetics Of

Physiological autophagy plays a crucial role in the regulation of muscle mass and metabolism, while the excessive induction or the inhibition of the autophagic flux contributes to the progression of several diseases. Autophagy can be activated by different stimuli, including cancer, exercise, caloric restriction and denervation. The latter leads to muscle atrophy through the activation of catabolic pathways, i.e. the ubiquitin-proteasome system and autophagy. However, the kinetics of autophagy activation and the upstream molecular pathways in denervated skeletal muscle have not been reported yet. In this study, we characterized the kinetics of autophagic induction, quickly triggered by denervation, and report the Akt/mTOR axis activation. Besides, with the aim to assess the relative contribution of autophagy in neurogenic muscle atrophy, we triggered autophagy with different stimuli along with denervation, and observed that four week-long autophagic induction, by either intermitted fasting or rapamycin treatment, did not significantly affect muscle mass loss. We conclude that: i) autophagy does not play a major role in inducing muscle loss following denervation; ii) nonetheless, autophagy may have a regulatory role in denervation induced muscle atrophy, since it is significantly upregulated as early as eight hours after denervation; iii) Akt/mTOR axis, AMPK and FoxO3a are activated consistently with the progression of muscle atrophy, further highlighting the complexity of the signaling response to the atrophying stimulus deriving from denervation.

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Activation of the ubiquitin-proteasome system contributes to oculopharyngeal muscular dystrophy through muscle atrophy

PLoS Genetics ◽

10.1371/journal.pgen.1010015 ◽

2022 ◽

Vol 18 (1) ◽

pp. e1010015

Author(s):

Cécile Ribot ◽

Cédric Soler ◽

Aymeric Chartier ◽

Sandy Al Hayek ◽

Rima Naït-Saïdi ◽

...

Keyword(s):

Muscular Dystrophy ◽

Muscle Atrophy ◽

Late Onset ◽

Oral Treatment ◽

Ubiquitin Proteasome System ◽

Proteasome Activity ◽

Functional Study ◽

Oculopharyngeal Muscular Dystrophy ◽

Ubiquitin Proteasome ◽

And Function

Oculopharyngeal muscular dystrophy (OPMD) is a late-onset disorder characterized by progressive weakness and degeneration of specific muscles. OPMD is due to extension of a polyalanine tract in poly(A) binding protein nuclear 1 (PABPN1). Aggregation of the mutant protein in muscle nuclei is a hallmark of the disease. Previous transcriptomic analyses revealed the consistent deregulation of the ubiquitin-proteasome system (UPS) in OPMD animal models and patients, suggesting a role of this deregulation in OPMD pathogenesis. Subsequent studies proposed that UPS contribution to OPMD involved PABPN1 aggregation. Here, we use a Drosophila model of OPMD to address the functional importance of UPS deregulation in OPMD. Through genome-wide and targeted genetic screens we identify a large number of UPS components that are involved in OPMD. Half dosage of UPS genes reduces OPMD muscle defects suggesting a pathological increase of UPS activity in the disease. Quantification of proteasome activity confirms stronger activity in OPMD muscles, associated with degradation of myofibrillar proteins. Importantly, improvement of muscle structure and function in the presence of UPS mutants does not correlate with the levels of PABPN1 aggregation, but is linked to decreased degradation of muscle proteins. Oral treatment with the proteasome inhibitor MG132 is beneficial to the OPMD Drosophila model, improving muscle function although PABPN1 aggregation is enhanced. This functional study reveals the importance of increased UPS activity that underlies muscle atrophy in OPMD. It also provides a proof-of-concept that inhibitors of proteasome activity might be an attractive pharmacological approach for OPMD.

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Noncoding RNA MaIL1 is an integral component of the TLR4–TRIF pathway

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1920393117 ◽

2020 ◽

Vol 117 (16) ◽

pp. 9042-9053 ◽

Cited By ~ 4

Author(s):

Marina Aznaourova ◽

Harshavardhan Janga ◽

Stephanie Sefried ◽

Andreas Kaufmann ◽

Jens Dorna ◽

...

Keyword(s):

Mammalian Cells ◽

Noncoding Rna ◽

Signal Transduction Pathway ◽

Ubiquitin Proteasome System ◽

Lavage Fluid ◽

Cellular Protein ◽

Type I ◽

Toll Like Receptor 4 ◽

Ubiquitin Proteasome ◽

Highly Correlated

RNA has been proposed as an important scaffolding factor in the nucleus, aiding protein complex assembly in the dense intracellular milieu. Architectural contributions of RNA to cytosolic signaling pathways, however, remain largely unknown. Here, we devised a multidimensional gradient approach, which systematically locates RNA components within cellular protein networks. Among a subset of noncoding RNAs (ncRNAs) cosedimenting with the ubiquitin–proteasome system, our approach unveiled ncRNA MaIL1 as a critical structural component of the Toll-like receptor 4 (TLR4) immune signal transduction pathway. RNA affinity antisense purification–mass spectrometry (RAP-MS) revealed MaIL1 binding to optineurin (OPTN), a ubiquitin-adapter platforming TBK1 kinase. MaIL1 binding stabilized OPTN, and consequently, loss of MaIL1 blunted OPTN aggregation, TBK1-dependent IRF3 phosphorylation, and type I interferon (IFN) gene transcription downstream of TLR4. MaIL1 expression was elevated in patients with active pulmonary infection and was highly correlated with IFN levels in bronchoalveolar lavage fluid. Our study uncovers MaIL1 as an integral RNA component of the TLR4–TRIF pathway and predicts further RNAs to be required for assembly and progression of cytosolic signaling networks in mammalian cells.

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Pueraria lobata and Daidzein Reduce Cytotoxicity by Enhancing Ubiquitin-Proteasome System Function in SCA3-iPSC-Derived Neurons

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/8130481 ◽

2019 ◽

Vol 2019 ◽

pp. 1-18

Author(s):

I-Cheng Chen ◽

Kuo-Hsuan Chang ◽

Yi-Jing Chen ◽

Yi-Chun Chen ◽

Guey-Jen Lee-Chen ◽

...

Keyword(s):

Proteasome Inhibitor ◽

Caspase 3 ◽

Neurodegenerative Disorder ◽

Ubiquitin Proteasome System ◽

Proteasome Activity ◽

Cag Repeats ◽

Spinocerebellar Ataxia Type ◽

Pueraria Lobata ◽

Protein Ubiquitination ◽

Ubiquitin Proteasome

Spinocerebellar ataxia type 3 (SCA3) is an autosomal dominant neurodegenerative disorder caused by a CAG repeat expansion within the ATXN3/MJD1 gene. The expanded CAG repeats encode a polyglutamine (polyQ) tract at the C-terminus of the ATXN3 protein. ATXN3 containing expanded polyQ forms aggregates, leading to subsequent cellular dysfunctions including an impaired ubiquitin-proteasome system (UPS). To investigate the pathogenesis of SCA3 and develop potential therapeutic strategies, we established induced pluripotent stem cell (iPSC) lines from SCA3 patients (SCA3-iPSC). Neurons derived from SCA3-iPSCs formed aggregates that are positive to the polyQ marker 1C2. Treatment with the proteasome inhibitor, MG132, on SCA3-iPSC-derived neurons downregulated proteasome activity, increased production of radical oxygen species (ROS), and upregulated the cleaved caspase 3 level and caspase 3 activity. This increased susceptibility to the proteasome inhibitor can be rescued by a Chinese herbal medicine (CHM) extract NH037 (from Pueraria lobata) and its constituent daidzein via upregulating proteasome activity and reducing protein ubiquitination, oxidative stress, cleaved caspase 3 level, and caspase 3 activity. Our results successfully recapitulate the key phenotypes of the neurons derived from SCA3 patients, as well as indicate the potential of NH037 and daidzein in the treatment for SCA3 patients.

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Preclinical Evaluation of a Food-Derived Functional Ingredient to Address Skeletal Muscle Atrophy

Nutrients ◽

10.3390/nu12082274 ◽

2020 ◽

Vol 12 (8) ◽

pp. 2274

Author(s):

Roi Cal ◽

Heidi Davis ◽

Alish Kerr ◽

Audrey Wall ◽

Brendan Molloy ◽

...

Keyword(s):

Skeletal Muscle ◽

Muscle Atrophy ◽

Soleus Muscle ◽

Murine Model ◽

The Body ◽

Skeletal Muscle Atrophy ◽

Type I ◽

Disuse Atrophy ◽

Tnf Α

Skeletal muscle is the metabolic powerhouse of the body, however, dysregulation of the mechanisms involved in skeletal muscle mass maintenance can have devastating effects leading to many metabolic and physiological diseases. The lack of effective solutions makes finding a validated nutritional intervention an urgent unmet medical need. In vitro testing in murine skeletal muscle cells and human macrophages was carried out to determine the effect of a hydrolysate derived from vicia faba (PeptiStrong: NPN_1) against phosphorylated S6, atrophy gene expression, and tumour necrosis factor alpha (TNF-α) secretion, respectively. Finally, the efficacy of NPN_1 on attenuating muscle waste in vivo was assessed in an atrophy murine model. Treatment of NPN_1 significantly increased the phosphorylation of S6, downregulated muscle atrophy related genes, and reduced lipopolysaccharide-induced TNF-α release in vitro. In a disuse atrophy murine model, following 18 days of NPN_1 treatment, mice exhibited a significant attenuation of muscle loss in the soleus muscle and increased the integrated expression of Type I and Type IIa fibres. At the RNA level, a significant upregulation of protein synthesis-related genes was observed in the soleus muscle following NPN_1 treatment. In vitro and preclinical results suggest that NPN_1 is an effective bioactive ingredient with great potential to prolong muscle health.

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The ubiquitin proteasome system in atrophying skeletal muscle: roles and regulation

AJP Cell Physiology ◽

10.1152/ajpcell.00125.2016 ◽

2016 ◽

Vol 311 (3) ◽

pp. C392-C403 ◽

Cited By ~ 57

Author(s):

Philippe A. Bilodeau ◽

Erin S. Coyne ◽

Simon S. Wing

Keyword(s):

Signaling Pathways ◽

Muscle Atrophy ◽

Molecular Mechanisms ◽

Muscle Wasting ◽

Clinical Problem ◽

Ubiquitin Proteasome System ◽

Mechanisms Of Action ◽

Loss Of Function ◽

Critical Determinant ◽

Ubiquitin Proteasome

Muscle atrophy complicates many diseases as well as aging, and its presence predicts both decreased quality of life and survival. Much work has been conducted to define the molecular mechanisms involved in maintaining protein homeostasis in muscle. To date, the ubiquitin proteasome system (UPS) has been shown to play an important role in mediating muscle wasting. In this review, we have collated the enzymes in the UPS whose roles in muscle wasting have been confirmed through loss-of-function studies. We have integrated information on their mechanisms of action to create a model of how they work together to produce muscle atrophy. These enzymes are involved in promoting myofibrillar disassembly and degradation, activation of autophagy, inhibition of myogenesis as well as in modulating the signaling pathways that control these processes. Many anabolic and catabolic signaling pathways are involved in regulating these UPS genes, but none appear to coordinately regulate a large number of these genes. A number of catabolic signaling pathways appear to instead function by inhibition of the insulin/IGF-I/protein kinase B anabolic pathway. This pathway is a critical determinant of muscle mass, since it can suppress key ubiquitin ligases and autophagy, activate protein synthesis, and promote myogenesis through its downstream mediators such as forkhead box O, mammalian target of rapamycin, and GSK3β, respectively. Although much progress has been made, a more complete inventory of the UPS genes involved in mediating muscle atrophy, their mechanisms of action, and their regulation will be useful for identifying novel therapeutic approaches to this important clinical problem.

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