Aerobic exercise training upregulates skeletal muscle calpain and ubiquitin-proteasome systems in healthy mice. Telma F Cunha,Jose B N Moreira,Nathalie A Paixão,Juliane C Campos,Alex W A Monteiro,Aline V N Bacurau,Carlos R Bueno,Julio C B Ferreira,Patricia C Brum Journal of applied physiology (Bethesda, Md. : 1985)
112
2012
Show Abstract
Aerobic exercise training (AET) is an important mechanical stimulus that modulates skeletal muscle protein turnover, leading to structural rearrangement. Since the ubiquitin-proteasome system (UPS) and calpain system are major proteolytic pathways involved in protein turnover, we aimed to investigate the effects of intensity-controlled AET on the skeletal muscle UPS and calpain system and their association to training-induced structural adaptations. Long-lasting effects of AET were studied in C57BL/6J mice after 2 or 8 wk of AET. Plantaris cross-sectional area (CSA) and capillarization were assessed by myosin ATPase staining. mRNA and protein expression levels of main components of the UPS and calpain system were evaluated in plantaris by real-time PCR and Western immunoblotting, respectively. No proteolytic system activation was observed after 2 wk of AET. Eight weeks of AET resulted in improved running capacity, plantaris capillarization, and CSA. Muscle RING finger-1 mRNA expression was increased in 8-wk-trained mice. Accordingly, elevated 26S proteasome activity was observed in the 8-wk-trained group, without accumulation of ubiquitinated or carbonylated proteins. In addition, calpain abundance was increased by 8 wk of AET, whereas no difference was observed in its endogenous inhibitor calpastatin. Taken together, our findings indicate that skeletal muscle enhancements, as evidenced by increased running capacity, plantaris capillarization, and CSA, occurred in spite of the upregulated UPS and calpain system, suggesting that overactivation of skeletal muscle proteolytic systems is not restricted to atrophying states. Our data provide evidence for the contribution of the UPS and calpain system to metabolic turnover of myofibrillar proteins and skeletal muscle adaptations to AET. | | 22461440
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Impact of obesity control on circulating level of endothelial progenitor cells and angiogenesis in response to ischemic stimulation. Yung-Lung Chen,Chia-Lo Chang,Cheuk-Kwan Sun,Chiung-Jen Wu,Tzu-Hsien Tsai,Sheng-Ying Chung,Sarah Chua,Kuo-Ho Yeh,Steve Leu,Jiunn-Jye Sheu,Fan-Yen Lee,Chia-Hung Yen,Hon-Kan Yip Journal of translational medicine
10
2012
Show Abstract
ABSTRACT: | | 22568992
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Intra-coronary administration of tacrolimus markedly attenuates infarct size and preserves heart function in porcine myocardial infarction. Sarah Chua,Steve Leu,Jiunn-Jye Sheu,Yu-Chun Lin,Li-Teh Chang,Ying-Hsien Kao,Chia-Hung Yen,Tzu-Hsien Tsai,Yung-Lung Chen,Hsueh-Wen Chang,Cheuk-Kwan Sun,Hon-Kan Yip Journal of inflammation (London, England)
9
2012
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ABSTRACT: | | 22658082
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Novel protective mechanisms for S-adenosyl-l-methionine against acetaminophen hepatotoxicity: Improvement of key antioxidant enzymatic function. James Michael Brown,John G Ball,Michael Scott Wright,Stephanie Van Meter,Monica A Valentovic Toxicology letters
212
2012
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Acetaminophen (APAP) overdose leads to severe hepatotoxicity, increased oxidative stress and mitochondrial dysfunction. S-adenosyl-l-methionine (SAMe) protects against APAP toxicity at a mmol/kg equivalent dose to N-acetylcysteine (NAC). SAMe acts as a principle biological methyl donor and participates in polyamine synthesis which increase cell growth and has a role in mitochondrial protection. The purpose of the current study tested the hypothesis that SAMe protects against APAP toxicity by maintaining critical antioxidant enzymes and markers of oxidative stress. Male C57Bl/6 mice were treated with vehicle (Veh; water 15ml/kg, ip), SAMe (1.25mmol/kg, ip), APAP (250mg/kg, ip), and SAMe+APAP (SAMe given 1h following APAP). Liver was collected 2 and 4h following APAP administration; mitochondrial swelling as well as hepatic catalase, glutathione peroxidase (GPx), glutathione reductase, and both Mn- and Cu/Zn-superoxide dismutase (SOD) enzyme activity were evaluated. Mitochondrial protein carbonyl, 3-nitrotyrosine cytochrome c leakage were analyzed by Western blot. SAMe significantly increased SOD, GPx, and glutathione reductase activity at 4h following APAP overdose. SAMe greatly reduced markers of oxidative stress and cytochrome C leakage following APAP overdose. Our studies also demonstrate that a 1.25mmol/kg dose of SAMe does not inhibit CYP 2E1 enzyme activity. The current study identifies a plausible mechanism for the decreased oxidative stress observed when SAMe is given following APAP. | | 22683606
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Exercise training prevents oxidative stress and ubiquitin-proteasome system overactivity and reverse skeletal muscle atrophy in heart failure. Telma F Cunha,Aline V N Bacurau,Jose B N Moreira,Nathalie A Paixão,Juliane C Campos,Julio C B Ferreira,Marcelo L Leal,Carlos E Negrão,Anselmo S Moriscot,Ulrik Wisløff,Patricia C Brum PloS one
7
2012
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Heart failure (HF) is known to lead to skeletal muscle atrophy and dysfunction. However, intracellular mechanisms underlying HF-induced myopathy are not fully understood. We hypothesized that HF would increase oxidative stress and ubiquitin-proteasome system (UPS) activation in skeletal muscle of sympathetic hyperactivity mouse model. We also tested the hypothesis that aerobic exercise training (AET) would reestablish UPS activation in mice and human HF. | | 22870245
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Chronic paracetamol treatment influences indices of reactive oxygen species accumulation in the aging Fischer 344 X Brown Norway rat aorta. Kevin M Rice,Sarath Meduru,Sunil K Kakarla,Anjaiah Katta,Sriram P Mupparaju,Brent Kidd,Lynne J Goebel,Eric R Blough Annals of clinical and laboratory science
42
2012
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Previous reports have demonstrated that increased levels of reactive oxygen species (ROS) and alterations in cell signaling characterize aging in the Fischer 344 X Brown Norway (FBN) rat aorta. Other work has suggested that increases in ROS may be related to vascular wall thickening and the development of hypertension. Paracetamol (acetaminophen) is a potent antioxidant that has been found to diminish free radicals in ischemia-reperfusion studies. However, it remains unclear whether chronic paracetamol administration influences signaling or ROS accumulation in the aging aorta. FBN rats (27 months old; n=8) were subjected to 6 months of treatment with a therapeutic dose of paracetamol (30 mg/kg/day) and compared to age-matched untreated FBN rat controls (n=8). Compared to measurements in the aortae of 6-month old animals, tunica media thickness, tissue superoxide levels, and protein oxidation levels were 38 ± 7%, 92 ± 31%, and 7 ± 2% higher in the aortae of 33-month control animals (p ?0.05). Chronic paracetamol treatment decreased tunica media thickness and the amount of oxidized protein by 13 ± 4% and 30 ± 1%, respectively (p ?0.05). This finding of diminished aortic thickening was associated with increased phosphorylation (activation) of the mitogen activated protein kinases and diminished levels of the anti-apoptotic protein Bcl-2. Taken together, these data suggest that chronic paracetamol treatment may decrease the deleterious effects of aging in the FBN rat aorta. | | 22585611
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Neuroglial alterations in rats submitted to the okadaic acid-induced model of dementia. Costa AP, Tramontina AC, Biasibetti R, Batassini C, Lopes MW, Wartchow KM, Bernardi C, Tortorelli LS, Leal RB, Gonçalves CA Behavioural brain research
226
420-7. Epub 2011 Oct 1.
2012
Show Abstract
Several types of animal models have been developed to investigate Alzheimer\'s disease (AD). Okadaic acid (OA), a potent inhibitor of phosphatases 1 and 2A, induces characteristics that resemble AD-like pathology. Memory impairment induced by intra-hippocampal injection of OA has been reported, accompanied by remarkable neuropathological changes including hippocampal neurodegeneration, a paired helical filament-like phosphorylation of tau protein, and formation of β-amyloid containing plaque-like structures. Rats were submitted to bilateral intrahippocampal okadaic acid-injection (100ng) and, 12 days after the surgery, behavioral and biochemical tests were performed. Using this model, we evaluated spatial cognitive deficit and neuroglial alterations, particularly astroglial protein markers such as glial fibrillary acidic protein (GFAP) and S100B, metabolism of glutamate, oxidative parameters and alterations in MAPKs. Our results indicate significant hippocampal changes, including increased GFAP, protein oxidation, and phosphorylation of p38(MAPK); and decreases in glutathione content, transporter EAAT2/GLT-1, and glutamine synthetase activity as well as a decrease in cerebrospinal fluid S100B. No alterations were observed in glutamate uptake activity and S100B content. In conclusion, the OA-induced model of dementia caused spatial cognitive deficit and oxidative stress in this model and, for the first time to our knowledge, specific astroglial alterations. Findings contribute to understanding diseases accompanied by cognitive deficits and the neural damage induced by AO administration.Copyright © 2011 Elsevier B.V. All rights reserved. | | 21982813
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Mononuclear iron enzymes are primary targets of hydrogen peroxide stress. Adil Anjem,James A Imlay The Journal of biological chemistry
287
2012
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This study tested whether nonredox metalloenzymes are commonly charged with iron in vivo and are primary targets of oxidative stress because of it. Indeed, three sample mononuclear enzymes, peptide deformylase, threonine dehydrogenase, and cytosine deaminase, were rapidly damaged by micromolar hydrogen peroxide in vitro and in live Escherichia coli. The first two enzymes use a cysteine residue to coordinate the catalytic metal atom; it was quantitatively oxidized by the radical generated by the Fenton reaction. Because oxidized cysteine can be repaired by cellular reductants, the effect was to avoid irreversible damage to other active-site residues. Nevertheless, protracted H(2)O(2) exposure gradually inactivated these enzymes, consistent with the overoxidation of the cysteine residue to sulfinic or sulfonic forms. During H(2)O(2) stress, E. coli defended all three proteins by inducing MntH, a manganese importer, and Dps, an iron-sequestration protein. These proteins appeared to collaborate in replacing the iron atom with nonoxidizable manganese. The implication is that mononuclear metalloproteins are common targets of H(2)O(2) and that both structural and metabolic arrangements exist to protect them. | | 22411989
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Autophagy proteins LC3B, ATG5 and ATG12 participate in quality control after mitochondrial damage and influence lifespan. Sören Mai,Britta Muster,Jürgen Bereiter-Hahn,Marina Jendrach Autophagy
8
2012
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Mitochondrial health is maintained by the quality control mechanisms of mitochondrial dynamics (fission and fusion) and mitophagy. Decline of these processes is thought to contribute to aging and neurodegenerative diseases. To investigate the role of mitochondrial quality control in aging on the cellular level, human umbilical vein endothelial cells (HUVEC) were subjected to mitochondria-targeted damage by combining staining of mitochondria and irradiation. This treatment induced a short boost of reactive oxygen species, which resulted in transient fragmentation of mitochondria followed by mitophagy, while mitochondrial dynamics were impaired. Furthermore, targeted mitochondrial damage upregulated autophagy factors LC3B, ATG5 and ATG12. Consequently these proteins were overexpressed in HUVEC as an in vitro aging model, which significantly enhanced the replicative life span up to 150% and the number of population doublings up to 200%, whereas overexpression of LAMP-1 did not alter the life span. Overexpression of LC3B, ATG5 and ATG12 resulted in an improved mitochondrial membrane potential, enhanced ATP production and generated anti-apoptotic effects, while ROS levels remained unchanged and the amount of oxidized proteins increased. Taken together, these data relate LC3B, ATG5 and ATG12 to mitochondrial quality control after oxidative damage, and to cellular longevity. | | 22170153
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Enhancement of proteasome function by PA28α overexpression protects against oxidative stress. Li J, Powell SR, Wang X The FASEB journal : official publication of the Federation of American Societies for Experimental Biology
25
883-93. Epub 2010 Nov 23.
2011
Show Abstract
The principal function of the proteasome is targeted degradation of intracellular proteins. Proteasome dysfunction has been observed in experimental cardiomyopathies and implicated in human congestive heart failure. Measures to enhance proteasome proteolytic function are currently lacking but would be beneficial in testing the pathogenic role of proteasome dysfunction and could have significant therapeutic potential. The association of proteasome activator 28 (PA28) with the 20S proteasome may play a role in antigen processing. It is unclear, however, whether the PA28 plays any important role outside of antigen presentation, although up-regulation of PA28 has been observed in certain types of cardiomyopathy. Here, we show that PA28α overexpression (PA28αOE) stabilized PA28β, increased 11S proteasomes, and enhanced the degradation of a previously validated proteasome surrogate substrate (GFPu) in cultured neonatal rat cardiomyocytes. PA28αOE significantly attenuated H(2)O(2)-induced increases in the protein carbonyls and markedly suppressed apoptosis in cultured cardiomyocytes under basal conditions or when stressed by H(2)O(2). We conclude that PA28αOE is sufficient to up-regulate 11S proteasomes, enhance proteasome-mediated removal of misfolded and oxidized proteins, and protect against oxidative stress in cardiomyocytes, providing a highly sought means to increase proteasomal degradation of abnormal cellular proteins. | | 21098724
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