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Erjavec N, Bayot A, Gareil M, Camougrand N, Nystrom T, Friguet B, Bulteau AL. Deletion of the mitochondrial Pim1/Lon protease in yeast results in accelerated aging and impairment of the proteasome. Free Radic Biol Med 2013; 56:9-16. [PMID: 23220263 DOI: 10.1016/j.freeradbiomed.2012.11.019] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 11/22/2012] [Indexed: 01/20/2023]
Abstract
The Saccharomyces cerevisiae homolog of the ATP-dependent Lon protease, Pim1p, is essential for mitochondrial protein quality control, DNA maintenance, and respiration. Here, we demonstrate that Pim1p activity declines in aging cells and that Pim1p deficiency shortens the replicative life span of yeast mother cells. This accelerated aging of pim1Δ cells is accompanied by elevated cytosolic levels of oxidized and aggregated proteins, as well as reduced proteasome activity. Overproduction of Hsp104p greatly diminishes aggregation of oxidized cytosolic proteins, rescues proteasome activity, and restores life span of pim1Δ cells to near wild-type levels. Our results show that defects in mitochondrial protein quality control have global intracellular effects leading to the increased generation of misfolded proteins and cytosolic protein aggregates, which are linked to a decline in replicative potential.
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Affiliation(s)
- Nika Erjavec
- Department of Cell and Molecular Biology, Gothenburg University, Göteborg 41390, Sweden
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2
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van Rijt SH, Keller IE, John G, Kohse K, Yildirim AÖ, Eickelberg O, Meiners S. Acute cigarette smoke exposure impairs proteasome function in the lung. Am J Physiol Lung Cell Mol Physiol 2012; 303:L814-23. [PMID: 22962013 DOI: 10.1152/ajplung.00128.2012] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cigarette smoke mediates DNA damage, lipid peroxidation, and modification and misfolding of proteins, thereby inducing severe cellular damage. The ubiquitin proteasome system serves as the major disposal system for modified and misfolded proteins and is thus essential for proper cellular function. Its role in cigarette smoke-induced cell damage, however, is largely unknown. We hypothesized that the ubiquitin-proteasome system is involved in the degradation of cigarette smoke-damaged proteins and that cigarette smoke exposure impairs the proteasome itself. Here, we show that treatment of human alveolar epithelial cells with cigarette smoke extract (CSE) induced time- and dose-dependent cell death, a rise in intracellular reactive oxygen species, and increased levels of carbonylated and polyubiquitinated proteins. While high doses of CSE severely impaired all three proteasomal activities, low CSE concentrations significantly inhibited only the trypsin-like activity of the proteasome in alveolar and bronchial epithelial cells. Moreover, acute exposure of mice to cigarette smoke significantly impaired the trypsin-like activity by 25% in the lungs. Reduced proteasome activity was not due to transcriptional regulation of the proteasome. Notably, cigarette smoke exposure induced accumulation of polyubiquitinated proteins in the soluble and insoluble protein fraction of the lung. We show for the first time that acute exposure to cigarette smoke directly impairs proteasome activity in the lungs of mice and in human epithelial cells at low doses without affecting proteasome expression. Our results indicate that defective proteasomal protein quality control may exacerbate the detrimental effects of cigarette smoke in the lung.
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Affiliation(s)
- Sabine H van Rijt
- Comprehensive Pneumology Center, University Hospital, Ludwig-Maximilians-University, Munich, Germany
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3
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Mapanga RF, Rajamani U, Dlamini N, Zungu-Edmondson M, Kelly-Laubscher R, Shafiullah M, Wahab A, Hasan MY, Fahim MA, Rondeau P, Bourdon E, Essop MF. Oleanolic acid: a novel cardioprotective agent that blunts hyperglycemia-induced contractile dysfunction. PLoS One 2012; 7:e47322. [PMID: 23091615 PMCID: PMC3473042 DOI: 10.1371/journal.pone.0047322] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 09/14/2012] [Indexed: 01/08/2023] Open
Abstract
Diabetes constitutes a major health challenge. Since cardiovascular complications are common in diabetic patients this will further increase the overall burden of disease. Furthermore, stress-induced hyperglycemia in non-diabetic patients with acute myocardial infarction is associated with higher in-hospital mortality. Previous studies implicate oxidative stress, excessive flux through the hexosamine biosynthetic pathway (HBP) and a dysfunctional ubiquitin-proteasome system (UPS) as potential mediators of this process. Since oleanolic acid (OA; a clove extract) possesses antioxidant properties, we hypothesized that it attenuates acute and chronic hyperglycemia-mediated pathophysiologic molecular events (oxidative stress, apoptosis, HBP, UPS) and thereby improves contractile function in response to ischemia-reperfusion. We employed several experimental systems: 1) H9c2 cardiac myoblasts were exposed to 33 mM glucose for 48 hr vs. controls (5 mM glucose); and subsequently treated with two OA doses (20 and 50 µM) for 6 and 24 hr, respectively; 2) Isolated rat hearts were perfused ex vivo with Krebs-Henseleit buffer containing 33 mM glucose vs. controls (11 mM glucose) for 60 min, followed by 20 min global ischemia and 60 min reperfusion ± OA treatment; 3) In vivo coronary ligations were performed on streptozotocin treated rats ± OA administration during reperfusion; and 4) Effects of long-term OA treatment (2 weeks) on heart function was assessed in streptozotocin-treated rats. Our data demonstrate that OA treatment blunted high glucose-induced oxidative stress and apoptosis in heart cells. OA therapy also resulted in cardioprotection, i.e. for ex vivo and in vivo rat hearts exposed to ischemia-reperfusion under hyperglycemic conditions. In parallel, we found decreased oxidative stress, apoptosis, HBP flux and proteasomal activity following ischemia-reperfusion. Long-term OA treatment also improved heart function in streptozotocin-diabetic rats. These findings are promising since it may eventually result in novel therapeutic interventions to treat acute hyperglycemia (in non-diabetic patients) and diabetic patients with associated cardiovascular complications.
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Affiliation(s)
- Rudo F. Mapanga
- Cardio-Metabolic Research Group (CMRG), Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Uthra Rajamani
- Cardio-Metabolic Research Group (CMRG), Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Nonkululeko Dlamini
- Discipline of Physiology, School of Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | | | - Roisin Kelly-Laubscher
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory, South Africa
| | - Mohammed Shafiullah
- Faculty of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Athiq Wahab
- Faculty of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Mohamed Y. Hasan
- Faculty of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Mohamed A. Fahim
- Faculty of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Philippe Rondeau
- Groupe d’Etude sur l’Inflammation Chronique et l’Obésité (GEICO), Université de La Réunion, Saint Denis de La Réunion, France
| | - Emmanuel Bourdon
- Groupe d’Etude sur l’Inflammation Chronique et l’Obésité (GEICO), Université de La Réunion, Saint Denis de La Réunion, France
| | - M. Faadiel Essop
- Cardio-Metabolic Research Group (CMRG), Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
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Abstract
The proteasome is an important component of the intracellular system for the turnover of proteins. The mammalian proteasome is engaged to degrade a bulky fraction of soluble intracellular proteins both in an ubiquitin-dependent and independent manner. The proteasome is composed by a central catalytic core--the 20S proteasome--where three different proteases are located, whose activities can be measured. A detailed protocol for measuring accurately the three activities of the 20S proteasome in cell and tissue homogenates, using specific fluorogenic substrates and a microplate reader fluorometer, are described. Successful applications of this method include determining changes in the proteasomal activities during aging, anti-aging interventions, cell cycle analysis, and in various disease states including neurodegenerative diseases and cancers.
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Trougakos IP, Gonos ES. Regulation of clusterin/apolipoprotein J, a functional homologue to the small heat shock proteins, by oxidative stress in ageing and age-related diseases. Free Radic Res 2007; 40:1324-34. [PMID: 17090421 DOI: 10.1080/10715760600902310] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Clusterin/apolipoprotein J (CLU) gene has a nearly ubiquitous expression pattern in human tissues. The two main CLU protein isoforms in human cells include the conventional glycosylated secreted heterodimer (sCLU) and a truncated nuclear form (nCLU). CLU has been implicated in various physiological processes and in many severe physiological disturbance states including ageing, cancer progression, vascular damage, diabetes, kidney and neuron degeneration. Although unrelated in their etiology and clinical manifestation, these diseases represent states of increased oxidative stress, which in turn, promotes amorphous aggregation of target proteins, increased genomic instability and high rates of cellular death. Among the various properties attributed to CLU so far, those mostly investigated and invariably appreciated are its small heat shock proteins-like chaperone activity and its involvement in cell death regulation, which are both directly correlated to the main features of oxidant injury. Moreover, the presence of both a heat shock transcription factor-1 and an activator protein-1 element in the CLU gene promoter indicate that CLU gene can be an extremely sensitive biosensor to reactive oxygen species. This review emphasizes on CLU gene regulation by oxidative stress that is the common link between all pathological conditions where CLU has been implicated.
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Affiliation(s)
- Ioannis P Trougakos
- Laboratory of Molecular & Cellular Ageing, Institute of Biological Research & Biotechnology, National Hellenic Research Foundation, Athens, Greece
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Bulteau AL, Moreau M, Saunois A, Nizard C, Friguet B. Algae extract-mediated stimulation and protection of proteasome activity within human keratinocytes exposed to UVA and UVB irradiation. Antioxid Redox Signal 2006; 8:136-43. [PMID: 16487047 DOI: 10.1089/ars.2006.8.136] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Sun exposure is the major environmental influence for epidermal cells; the harmful effect of UV radiation on skin is related to the generation of reactive oxygen species that alter cellular components including proteins. It is now well established that the proteasome is responsible for the degradation of most of oxidized proteins and that impairment of proteasome function is a hallmark of cellular aging. In a previous study, we investigated the effects of UV irradiation on proteasomes in human keratinocyte cultures and showed that all three peptidase activities were decreased 24 h after irradiation of the cells. Increased levels of oxidatively modified proteins were observed in irradiated cells and were found to act as endogenous inhibitors of the proteasome. We report here on the stimulating and protective effects of an algae extract, prepared from Phaeodactylum tricornutum, on proteasome peptidase activities of human keratinocytes exposed to UVA and UVB irradiation. In addition, preserving proteasome function resulted in lowering the extent of the irradiation-induced protein oxidative damage, opening up new strategies for protection of epidermal cells against the detrimental effects of UV irradiation.
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Affiliation(s)
- Anne-Laure Bulteau
- Laboratoire de Biologie et Biochimie Cellulaire du Vieillissement, Université Paris 7-Denis Diderot, Paris, France
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Asher G, Tsvetkov P, Kahana C, Shaul Y. A mechanism of ubiquitin-independent proteasomal degradation of the tumor suppressors p53 and p73. Genes Dev 2005; 19:316-21. [PMID: 15687255 PMCID: PMC546509 DOI: 10.1101/gad.319905] [Citation(s) in RCA: 285] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Protein degradation is an essential and highly regulated process. The proteasomal degradation of the tumor suppressors p53 and p73 is regulated by both polyubiquitination and by an ubiquitin-independent process. Here, we show that this ubiquitin-independent process is mediated by the 20S proteasomes and is regulated by NQO1. NQO1 physically interacts with p53 and p73 in an NADH-dependent manner and protects them from 20S proteasomal degradation. Remarkably, the vast majority of NQO1 in cells is found in physical association with the 20S proteasomes, suggesting that NQO1 functions as a gatekeeper of the 20S proteasomes. We further show that this pathway plays a role in p53 accumulation in response to ionizing radiation. Our findings provide the first evidence for in vivo degradation of p53 and p73 by the 20S proteasomes and its regulation by NQO1 and NADH level.
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Affiliation(s)
- Gad Asher
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
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Das S, Powell SR, Wang P, Divald A, Nesaretnam K, Tosaki A, Cordis GA, Maulik N, Das DK. Cardioprotection with palm tocotrienol: antioxidant activity of tocotrienol is linked with its ability to stabilize proteasomes. Am J Physiol Heart Circ Physiol 2005; 289:H361-7. [PMID: 15708953 DOI: 10.1152/ajpheart.01285.2004] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tocotrienols, isomers of vitamin E, have been found to possess many health benefits. The present study was designed to determine whether tocotrienol has a direct cardioprotective role. Isolated rat hearts were perfused for 15 min with Krebs-Ringer bicarbonate buffer in the absence or presence of palm tocotrienol derived from the tocotrienol-rich fraction (0.035%) of palm oil (TRF). In another group of studies, the hearts were preperfused for 15 min in the presence of a c-Src inhibitor, 4-amino-5-(4-methylphenyl)-7-(t-butyl)-pyrazolo-3,4-d-pyrimidine (PPI). The hearts were then subjected to 30 min of global ischemia followed by 2 h of reperfusion. As expected, ischemia-reperfusion caused ventricular dysfunction, electrical rhythm disturbances, and increased myocardial infarct size. PPI or TRF could reverse the ischemia-reperfusion-mediated cardiac dysfunction. Ischemia-reperfusion also upregulated c-Src expression and phosphorylation. Although TRF only minimally affected c-Src expression, it significantly inhibited the phosphorylation of c-Src. Ischemia-reperfusion reduced 20S and 26S proteasome activities, an effect prevented by TRF pretreatment. PPI exerted a cardioprotective effect that is not mediated by the proteasome but, rather, through direct inhibition of c-Src. The results of this study support a role for c-Src in postischemic cardiac injury and dysfunction and demonstrate direct cardioprotective effects of TRF. The cardioprotective properties of TRF appear to be due to inhibition of c-Src activation and proteasome stabilization.
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Affiliation(s)
- Samarjit Das
- Cardiovascular Research Center, Univ. of Connecticut, School of Medicine, Farmington, CT 06030-1110, USA.
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McBride WH, Chiang CS, Olson JL, Wang CC, Hong JH, Pajonk F, Dougherty GJ, Iwamoto KS, Pervan M, Liao YP. A Sense of Danger from Radiation1. Radiat Res 2004; 162:1-19. [PMID: 15222781 DOI: 10.1667/rr3196] [Citation(s) in RCA: 234] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Tissue damage caused by exposure to pathogens, chemicals and physical agents such as ionizing radiation triggers production of generic "danger" signals that mobilize the innate and acquired immune system to deal with the intrusion and effect tissue repair with the goal of maintaining the integrity of the tissue and the body. Ionizing radiation appears to do the same, but less is known about the role of "danger" signals in tissue responses to this agent. This review deals with the nature of putative "danger" signals that may be generated by exposure to ionizing radiation and their significance. There are a number of potential consequences of "danger" signaling in response to radiation exposure. "Danger" signals could mediate the pathogenesis of, or recovery from, radiation damage. They could alter intrinsic cellular radiosensitivity or initiate radioadaptive responses to subsequent exposure. They may spread outside the locally damaged site and mediate bystander or "out-of-field" radiation effects. Finally, an important aspect of classical "danger" signals is that they link initial nonspecific immune responses in a pathological site to the development of specific adaptive immunity. Interestingly, in the case of radiation, there is little evidence that "danger" signals efficiently translate radiation-induced tumor cell death into the generation of tumor-specific immunity or normal tissue damage into autoimmunity. The suggestion is that radiation-induced "danger" signals may be inadequate in this respect or that radiation interferes with the generation of specific immunity. There are many issues that need to be resolved regarding "danger" signaling after exposure to ionizing radiation. Evidence of their importance is, in some areas, scant, but the issues are worthy of consideration, if for no other reason than that manipulation of these pathways has the potential to improve the therapeutic benefit of radiation therapy. This article focuses on how normal tissues and tumors sense and respond to danger from ionizing radiation, on the nature of the signals that are sent, and on the impact on the eventual consequences of exposure.
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Affiliation(s)
- William H McBride
- Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1714, USA.
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Gozal D, Row BW, Kheirandish L, Liu R, Guo SZ, Qiang F, Brittian KR. Increased susceptibility to intermittent hypoxia in aging rats: changes in proteasomal activity, neuronal apoptosis and spatial function. J Neurochem 2003; 86:1545-52. [PMID: 12950463 DOI: 10.1046/j.1471-4159.2003.01973.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Obstructive sleep apnea (OSA) is a frequent medical condition characterized by intermittent hypoxia (IH) during sleep, and is associated with neurodegenerative changes in several brain regions along with learning deficits. We hypothesized that aging rats exposed to IH during sleep would be particularly susceptible. Young (3-4 months) and aging (20-22 months) Sprague-Dawley rats were therefore exposed to either room air or IH for 14 days. Learning and memory was assessed with a standard place-training version of the Morris water maze. Aging rats exposed to room air (RA) or IH displayed significant spatial learning impairments compared with similarly exposed young rats; furthermore, the decrements in performance between RA and IH were markedly greater in aging compared with young rats (p < 0.01), and coincided with the magnitude of IH-induced decreases in cyclic AMP response element binding (CREB) phosphorylation. Furthermore, decreases in proteasomal activity occurred in both young and aging rats exposed to IH, but were substantially greater in the latter (p < 0.001). Neuronal apoptosis, as shown by cleaved caspase 3 expression, was particularly increased in aging rats exposed to IH (p < 0.01 versus young rats exposed to IH). Collectively, these findings indicate unique vulnerability of the aging rodent brain to IH, which is reflected at least in part, by the more prominent decreases in CREB phosphorylation and a marked inability of the ubiquitin-proteasomal pathway to adequately clear degraded proteins.
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Affiliation(s)
- David Gozal
- Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville, Kentucky, USA.
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Hermann J, Gulati R, Napoli C, Woodrum JE, Lerman LO, Rodriguez-Porcel M, Sica V, Simari RD, Ciechanover A, Lerman A. Oxidative stress-related increase in ubiquitination in early coronary atherogenesis. FASEB J 2003; 17:1730-2. [PMID: 12958191 DOI: 10.1096/fj.02-0841fje] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The ubiquitin-proteasome system (UPS) is involved in the removal of damaged proteins and the activation of transcription factors, such as nuclear-factor-kappaB. Recent reports, however, questioned the functional activity of the UPS under conditions of increased oxidative stress, such as experimental hypercholesterolemia, which was the objective of our study. Pigs were placed on a normal chow diet (N) or on a hypercholesterolemic diet without (HC) or with vitamin C and E supplementation (HC+VIT) for 12 weeks. Compared with N, plasma concentration of total cholesterol increased in both HC and HC+VIT [76 +/- 21 vs. 400 +/- 148 (P<0.05) and 329 +/- 102 (P<0.05) mg/dL], whereas increase in lipid peroxidation, as assessed by LDL-malondialdehyde plasma concentration, was found in HC but not in HC+VIT [6.6 +/- 0.7 vs. 8.5 +/- 0.3 (P<0.05) and 6.8 +/- 0.7 nmol/mg protein]. In comparison with N, the level of ubiquitin conjugates in the coronary artery, as assessed by immunoblotting, increased by 42% in HC but not in HC+VIT and was localized predominantly to media vascular smooth muscle cells by immunostaining. There was no difference in proteasome proteolytic activity among the study groups. These results demonstrate that the UPS is functionally active in early atherogenesis despite increase in oxidative stress with important repercussions in the pathophysiology and therapy of cardiovascular diseases.
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Affiliation(s)
- Joerg Hermann
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA
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