Mechanical ventilation induces alterations of the ubiquitin-proteasome pathway in the diaphragm

2005 ◽  
Vol 98 (4) ◽  
pp. 1314-1321 ◽  
Author(s):  
Keith C. DeRuisseau ◽  
Andreas N. Kavazis ◽  
Melissa A. Deering ◽  
Darin J. Falk ◽  
Darin Van Gammeren ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Control Group ◽  
20S Proteasome ◽  
Mrna Levels ◽  
Α Subunit ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Conjugating Enzyme ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Conjugating Enzyme

Prolonged mechanical ventilation (MV) results in diaphragmatic atrophy due, in part, to an increase in proteolysis. These experiments tested the hypothesis that MV-induced diaphragmatic proteolysis is accompanied by increased expression of key components of the ubiquitin-proteasome pathway (UPP). To test this postulate, we investigated the effect of prolonged MV on UPP components and determined the trypsin-like and peptidylglutamyl peptide hydrolyzing activities of the 20S proteasome. Adult Sprague-Dawley rats were assigned to either control or 12-h MV groups ( n = 7/group). MV animals were anesthetized, tracheostomized, and ventilated with room air for 12 h. Animals in the control group were acutely anesthetized but not exposed to MV. Compared with controls, MV animals demonstrated increased diaphragmatic mRNA levels of two ubiquitin ligases, muscle atrophy F-box (+8.3-fold) and muscle ring finger 1 (+19.0-fold). However, MV did not alter mRNA levels of 14-kDa ubiquitin-conjugating enzyme, polyubiquitin, proteasome-activating complex PA28, or 20S α-subunit 7. Protein levels of 14-kDa ubiquitin-conjugating enzyme and proteasome-activating complex PA28 were not altered following MV, but 20S α-subunit 7 levels declined (−17.7%). MV increased diaphragmatic trypsin-like activity (+31%) but did not alter peptidylglutamyl peptide hydrolyzing activity. Finally, compared with controls, MV increased ubiquitin-protein conjugates in both the myofibrillar (+24.9%) and cytosolic (+54.7%) fractions of the diaphragm. These results are consistent with the hypothesis that prolonged MV increases diaphragmatic levels of key components within the UPP and that increases in 20S proteasome activity contribute to MV-induced diaphragmatic proteolysis and atrophy.

scholarly journals Role of Ubiquitin-Conjugating Enzyme UBE2C in Gastrointestinal Cancers

2021 ◽  
Vol 5 (5) ◽  
pp. 64-72
Author(s):  
Ce Guo ◽  
Xing Guo ◽  
Zhen Wei ◽  
Qian Wang ◽  
Huiqing Zhang
Keyword(s):  
Prognostic Marker ◽  
Therapeutic Target ◽  
Potential Role ◽  
Gastrointestinal Cancers ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Conjugating Enzyme ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Conjugating Enzyme

Ubiquitin-conjugating enzyme UBE2C is one of the important members of ubiquitin-proteasome pathway (UPP). Amplification and/or overexpression of UBE2C have been reported in many malignancies, and a high expression of UBE2C is associated with poor clinical outcomes. In this review, the pathological role of dysregulated UBE2C in gastrointestinal cancers and its potential role as a diagnostic and/or a prognostic marker as well as a therapeutic target in these cancers are discussed.

scholarly journals Toll-like Receptor 4 Signaling in Ventilator-induced Diaphragm Atrophy

2012 ◽  
Vol 117 (2) ◽  
pp. 329-338 ◽  
Author(s):  
Willem-Jan M. Schellekens ◽  
Hieronymus W. H. van Hees ◽  
Michiel Vaneker ◽  
Marianne Linkels ◽  
P. N. Richard Dekhuijzen ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Caspase 3 ◽  
Toll Like Receptor ◽  
Wild Type ◽  
Toll Like Receptor 4 ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Diaphragm Atrophy ◽  
Deficient Mice

Background Mechanical ventilation induces diaphragm muscle atrophy, which plays a key role in difficult weaning from mechanical ventilation. The signaling pathways involved in ventilator-induced diaphragm atrophy are poorly understood. The current study investigated the role of Toll-like receptor 4 signaling in the development of ventilator-induced diaphragm atrophy. Methods Unventilated animals were selected for control: wild-type (n = 6) and Toll-like receptor 4 deficient mice (n = 6). Mechanical ventilation (8 h): wild-type (n = 8) and Toll-like receptor 4 deficient (n = 7) mice.Myosin heavy chain content, proinflammatory cytokines, proteolytic activity of the ubiquitin-proteasome pathway, caspase-3 activity, and autophagy were measured in the diaphragm. Results Mechanical ventilation reduced myosin content by approximately 50% in diaphragms of wild-type mice (P less than 0.05). In contrast, ventilation of Toll-like receptor 4 deficient mice did not significantly affect diaphragm myosin content. Likewise, mechanical ventilation significantly increased interleukin-6 and keratinocyte-derived chemokine in the diaphragm of wild-type mice, but not in ventilated Toll-like receptor 4 deficient mice. Mechanical ventilation increased diaphragmatic muscle atrophy factor box transcription in both wild-type and Toll-like receptor 4 deficient mice. Other components of the ubiquitin-proteasome pathway and caspase-3 activity were not affected by ventilation of either wild-type mice or Toll-like receptor 4 deficient mice. Mechanical ventilation induced autophagy in diaphragms of ventilated wild-type mice, but not Toll-like receptor 4 deficient mice. Conclusion Toll-like receptor 4 signaling plays an important role in the development of ventilator-induced diaphragm atrophy, most likely through increased expression of cytokines and activation of lysosomal autophagy.

scholarly journals The Proteasome Inhibitor, MG132, Attenuates Diabetic Nephropathy by Inhibiting SnoN DegradationIn VivoandIn Vitro

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Wei Huang ◽  
Chen Yang ◽  
Qinling Nan ◽  
Chenlin Gao ◽  
Hong Feng ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
High Glucose ◽  
Proteasome Inhibitor ◽  
Kidney Damage ◽  
Control Group ◽  
Glomerular Mesangial Cells ◽  
Proteasome Inhibitor Mg132 ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway

Transforming growth factor-β(TGF-β) has been shown to be involved in diabetic nephropathy (DN). The SnoN protein can regulate TGF-βsignaling through interaction with Smad proteins. Recent studies have shown that SnoN is mainly degraded by the ubiquitin-proteasome pathway. However, the role of SnoN in the regulation of TGF-β/Smad signaling in DN is still unclear. In this study, diabetic rats were randomly divided into a diabetic control group (DC group) and a proteasome inhibitor (MG132) diabetes therapy group (DT group). Kidney damage parameters and the expression of SnoN, Smurf2, and TGF-βwere observed. Simultaneously, we cultured rat glomerular mesangial cells (GMCs) stimulated with high glucose, and SnoN and Arkadia expression were measured. Results demonstrated that 24-hour urine protein, ACR, BUN, and the expression of Smurf2 and TGF-βwere significantly increased (P<0.05), whereas SnoN was significantly decreased in the DC group (P<0.05). However, these changes diminished after treatment with MG132. SnoN expression in GMCs decreased significantly (P<0.05), but Arkadia expression gradually increased due to high glucose stimulation (P<0.05), which could be almost completely reversed by MG132 (P<0.05). The present results support the hypothesis that MG132 may alleviate kidney damage by inhibiting SnoN degradation and TGF-βactivation, suggesting that the ubiquitin-proteasome pathway may become a new therapeutic target for DN.

Mechanisms of Cancer Cachexia

2009 ◽  
Vol 89 (2) ◽  
pp. 381-410 ◽  
Author(s):  
Michael J. Tisdale
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Adipose Tissue ◽  
Protein Degradation ◽  
Initiation Factor ◽  
Tissue Loss ◽  
Α Subunit ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway

Up to 50% of cancer patients suffer from a progressive atrophy of adipose tissue and skeletal muscle, called cachexia, resulting in weight loss, a reduced quality of life, and a shortened survival time. Anorexia often accompanies cachexia, but appears not to be responsible for the tissue loss, particularly lean body mass. An increased resting energy expenditure is seen, possibly arising from an increased thermogenesis in skeletal muscle due to an increased expression of uncoupling protein, and increased operation of the Cori cycle. Loss of adipose tissue is due to an increased lipolysis by tumor or host products. Loss of skeletal muscle in cachexia results from a depression in protein synthesis combined with an increase in protein degradation. The increase in protein degradation may include both increased activity of the ubiquitin-proteasome pathway and lysosomes. The decrease in protein synthesis is due to a reduced level of the initiation factor 4F, decreased elongation, and decreased binding of methionyl-tRNA to the 40S ribosomal subunit through increased phosphorylation of eIF2 on the α-subunit by activation of the dsRNA-dependent protein kinase, which also increases expression of the ubiquitin-proteasome pathway through activation of NFκB. Tumor factors such as proteolysis-inducing factor and host factors such as tumor necrosis factor-α, angiotensin II, and glucocorticoids can all induce muscle atrophy. Knowledge of the mechanisms of tissue destruction in cachexia should improve methods of treatment.

Regulation of elastin gene transcription by proteasome dysfunction

2005 ◽  
Vol 289 (3) ◽  
pp. C766-C773 ◽  
Author(s):  
Ping-Ping Kuang ◽  
Ronald H. Goldstein
Keyword(s):  
Gene Expression ◽  
Gene Transcription ◽  
Proteasome Inhibitors ◽  
Lung Fibroblasts ◽  
Extracellular Matrix Protein ◽  
Mrna Levels ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Elastin Gene

Elastin, a major extracellular matrix protein and the core component of elastic fiber, is essential to maintain lung structural integrity and normal physiological function. We previously found that the downregulation of elastin gene transcription by IL-1β is mediated via activation of NF-κB and CCAAT/enhancer binding protein (C/EBP)β, both targets of the ubiquitin-proteasome pathway. To further investigate the molecular mechanisms that underlie the control of elastin gene expression, we disrupted the ubiquitin-proteasome pathway with specific proteasome inhibitors. We found that specific proteasome inhibitors decreased the steady-state level of elastin mRNA in a dose-responsive manner. Run-on assay and promoter reporter study indicated that the proteasome inhibitor MG-132 repressed the rate of elastin transcription. MG-132 did not affect mRNA levels of NF-κB and C/EBPβ, or the nuclear presence of NF-κB, but markedly increased C/EBPβ isoforms, including liver-enriched transcriptional activating protein and liver-enriched transcriptional inhibitory protein. Addition of cycloheximide blocked these increases and the downregulation of elastin mRNA by MG-132. The MG-132-induced downregulation of elastin transcription was dependent on C/EBPβ expression as assessed with small interfering RNA. These results indicate that the ubiquitin-proteasome pathway plays an essential role in maintaining elastin gene expression in lung fibroblasts. Disruption of this pathway results in the downregulation of tropoelastin transcription via posttranscriptionally induced C/EBPβ isoforms.

Clenbuterol induces muscle-specific attenuation of atrophy through effects on the ubiquitin-proteasome pathway

2005 ◽  
Vol 99 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Tossaporn Yimlamai ◽  
Stephen L. Dodd ◽  
Stephen E. Borst ◽  
Sooyeon Park
Keyword(s):  
Muscle Atrophy ◽  
Tibialis Anterior ◽  
Weight Bearing ◽  
Ubiquitin Proteasome Pathway ◽  
Igf I ◽  
Ubiquitin Conjugating Enzyme ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway ◽  
Slow Twitch Fibers ◽  
Fast Twitch

The ubiquitin-proteasome pathway is primarily responsible for myofibrillar protein degradation during hindlimb unweighting (HU). β-Adrenergic agonists such as clenbuterol (CB) induce muscle hypertrophy and attenuate muscle atrophy due to disuse or inactivity. However, the molecular mechanism by which CB exerts these effects remains poorly understood. The aims of this study were to investigate whether CB attenuates HU-induced muscle atrophy through an inhibition of the ubiquitin-proteasome pathway and whether insulin-like growth factor I (IGF-I) mediates this inhibition. Rats were randomized to the following groups: weight-bearing control, 14-day CB-treated, 14-day HU, and CB + HU. HU-induced atrophy was associated with increased proteolysis and upregulation of components of the ubiquitin-proteasome pathway (ubiquitin conjugates, ubiquitin conjugating enzyme E2-14kDa, and 20S proteasome activity). Upregulation of the ubiquitin proteasome occurred in all muscles tested but was more pronounced in muscles composed primarily of slow-twitch fibers (soleus) than in fast-twitch muscles (plantaris and tibialis anterior). Although CB induced hypertrophy in all muscles, CB attenuated the HU-induced atrophy and reduced ubiquitin conjugates only in the fast plantaris and tibialis anterior and not in the slow soleus muscle. CB did not elevate IGF-I protein content in either of the muscles examined. These results suggest that CB induces hypertrophy and alleviates HU-induced atrophy, particularly in the fast muscles, at least in part through a muscle-specific inhibition of the ubiquitin-proteasome pathway and that these effects are not mediated by the local production of IGF-I in skeletal muscle.

Skeletal muscle mRNA levels for cathepsin B, but not components of the ubiquitin–proteasome pathway, are increased in patients with lung cancer referred for thoracotomy

2002 ◽  
Vol 102 (3) ◽  
pp. 353-361 ◽  
Author(s):  
R. Thomas JAGOE ◽  
Christopher P.F. REDFERN ◽  
Russell G. ROBERTS ◽  
G. John GIBSON ◽  
Timothy H.J. GOODSHIP
Keyword(s):  
Gene Expression ◽  
Lung Cancer ◽  
Skeletal Muscle ◽  
Cathepsin B ◽  
Muscle Wasting ◽  
Fat Free Mass ◽  
Mrna Levels ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway

Muscle wasting is a common and prominent feature of advanced cancer, including lung cancer. Evidence from animal experiments suggests that accelerated proteolysis via the ubiquitin-proteasome pathway is the primary cause of cancer-related cachexia. However, there are few data on the role of this pathway in determining muscle wasting in human cancer. The present study was designed to measure whether skeletal muscle gene expression of components of the ubiquitin-proteasome pathway and/or the lysosomal proteolytic pathway was increased in patients with early lung cancer. A total of 36 patients with lung cancer referred for curative resection and 10 control subjects had biopsies of latissimus dorsi muscle taken at operation. mRNA levels of four components of the ubiquitin-proteasome pathway, i.e. polyubiquitin, C2α proteasome subunit, 14kDa ubiquitin-carrier protein and ubiquitin-activating protein, and of two lysosomal proteolytic enzymes, i.e. cathepsin B and cathepsin D, were measured using quantitative Northern blotting. mRNA levels for cathepsin B, but not for components of the ubiquitin-proteasome pathway, were higher in patients with cancer compared with controls (P = 0.01). Among lung cancer patients, cathepsin B mRNA levels correlated with fat-free mass index (r =-0.57, P = 0.003) and tumour stage (rs = 0.45, P = 0.03), and were higher in smokers (P = 0.04). Thus gene expression of the lysosomal protease cathepsin B is increased in the skeletal muscle of patients with early lung cancer, and the strong inverse relationship with fat-free mass suggests that cathepsin B may have a role in inducing muscle wasting in the early stages of lung cancer.

Skeletal muscle mRNA levels for cathepsin B, but not components of the ubiquitin‒proteasome pathway, are increased in patients with lung cancer referred for thoracotomy

2002 ◽  
Vol 102 (3) ◽  
pp. 353 ◽  
Author(s):  
R. Thomas JAGOE ◽  
Christopher P. F. REDFERN ◽  
Russell G. ROBERTS ◽  
G. John GIBSON ◽  
Timothy H. J. GOODSHIP
Keyword(s):  
Lung Cancer ◽  
Skeletal Muscle ◽  
Cathepsin B ◽  
Mrna Levels ◽  
Ubiquitin Proteasome Pathway ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway

scholarly journals Proteasome inhibitors: new class of antitumor agents

2003 ◽  
Vol 3 (4) ◽  
pp. 5-10
Author(s):  
Gordan Srkalović
Keyword(s):  
Antitumor Agents ◽  
Proteasome Inhibitors ◽  
26S Proteasome ◽  
Ubiquitin Proteasome Pathway ◽  
Cellular Processes ◽  
New Class ◽  
C Terminus ◽  
Ubiquitin Conjugating Enzyme ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway

The ubiquitin-proteasome pathway is the principal pathway for intracellular protein degradation1,2 (Fig 1). This pathway selectively degrades an extensive number of short-lived regulatory proteins involved in the control of normal cellular processes. In order to be degraded, proteins targeted by the ubiquitin-proteasome pathway are covalently tagged by polyubiquitination, via a three-step enzymatic process, which ultimately leads to their recognition and degradation, by the 26S proteasome in a highly specific and regulated manner. This process is accomplished by the sequential action of three enzymes: an ATP-dependent ubiquitin-activating enzyme (E1), an ubiquitin-conjugating enzyme (E2) and an ubiquitin-pro-tein ligase (E3).3 This cascade covalently links the C terminus of ubiquitin to a free amino group on the target protein, usually the ε-amino of a lysine residue.

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