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Deng R, Wang F, Wang L, Xiong L, Shen X, Song H. Advances in Plant Polysaccharides as Antiaging Agents: Effects and Signaling Mechanisms. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:7175-7191. [PMID: 37155561 DOI: 10.1021/acs.jafc.3c00493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Aging refers to the gradual physiological changes that occur in an organism after reaching adulthood, resulting in senescence and a decline in biological functions, ultimately leading to death. Epidemiological evidence shows that aging is a driving factor in the developing of various diseases, including cardiovascular diseases, neurodegenerative diseases, immune system disorders, cancer, and chronic low-grade inflammation. Natural plant polysaccharides have emerged as crucial food components in delaying the aging process. Therefore, it is essential to continuously investigate plant polysaccharides as potential sources of new pharmaceuticals for aging. Modern pharmacological research indicates that plant polysaccharides can exert antiaging effects by scavenging free radicals, increasing telomerase activity, regulating apoptosis, enhancing immunity, inhibiting glycosylation, improving mitochondrial dysfunction regulating gene expression, activating autophagy, and modulating gut microbiota. Moreover, the antiaging activity of plant polysaccharides is mediated by one or more signaling pathways, including IIS, mTOR, Nrf2, NF-κB, Sirtuin, p53, MAPK, and UPR signaling pathways. This review summarizes the antiaging properties of plant polysaccharides and signaling pathways participating in the polysaccharide-regulating aging process. Finally, we discuss the structure-activity relationships of antiaging polysaccharides.
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Affiliation(s)
- Rou Deng
- College of Food Science and Engineering, Collaborative Innovation Center for Modern Grain Circulation and Safety, Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Fang Wang
- College of Food Science and Engineering, Collaborative Innovation Center for Modern Grain Circulation and Safety, Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Luanfeng Wang
- College of Food Science and Engineering, Collaborative Innovation Center for Modern Grain Circulation and Safety, Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Ling Xiong
- College of Food Science and Engineering, Collaborative Innovation Center for Modern Grain Circulation and Safety, Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Xinchun Shen
- College of Food Science and Engineering, Collaborative Innovation Center for Modern Grain Circulation and Safety, Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
| | - Haizhao Song
- College of Food Science and Engineering, Collaborative Innovation Center for Modern Grain Circulation and Safety, Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing University of Finance and Economics, Nanjing 210023, China
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Pisani A, Paciello F, Montuoro R, Rolesi R, Galli J, Fetoni AR. Antioxidant Therapy as an Effective Strategy against Noise-Induced Hearing Loss: From Experimental Models to Clinic. Life (Basel) 2023; 13:life13041035. [PMID: 37109564 PMCID: PMC10144536 DOI: 10.3390/life13041035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 04/29/2023] Open
Abstract
Cochlear redox unbalance is the main mechanism of damage involved in the pathogenesis of noise-induced-hearing loss. Indeed, the increased free radical production, in conjunction with a reduced efficacy of the endogenous antioxidant system, plays a key role in cochlear damage induced by noise exposure. For this reason, several studies focused on the possibility to use exogenous antioxidant to prevent or attenuate noise-induce injury. Thus, several antioxidant molecules, alone or in combination with other compounds, have been tested in both experimental and clinical settings. In our findings, we tested the protective effects of several antioxidant enzymes, spanning from organic compounds to natural compounds, such as nutraceuticals of polyphenols. In this review, we summarize and discuss the strengths and weaknesses of antioxidant supplementation focusing on polyphenols, Q-Ter, the soluble form of CoQ10, Vitamin E and N-acetil-cysteine, which showed great otoprotective effects in different animal models of noise induced hearing loss and which has been proposed in clinical trials.
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Affiliation(s)
- Anna Pisani
- Department of Otolaryngology Head and Neck Surgery, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Fabiola Paciello
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Raffaele Montuoro
- Department of Otolaryngology Head and Neck Surgery, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Rolando Rolesi
- Department of Otolaryngology Head and Neck Surgery, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Jacopo Galli
- Department of Otolaryngology Head and Neck Surgery, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Anna Rita Fetoni
- Department of Neuroscience, Reproductive Sciences and Dentistry-Audiology Section, University of Naples Federico II, 80131 Naples, Italy
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Paciello F, Ripoli C, Fetoni AR, Grassi C. Redox Imbalance as a Common Pathogenic Factor Linking Hearing Loss and Cognitive Decline. Antioxidants (Basel) 2023; 12:antiox12020332. [PMID: 36829891 PMCID: PMC9952092 DOI: 10.3390/antiox12020332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/23/2023] [Accepted: 01/29/2023] [Indexed: 02/04/2023] Open
Abstract
Experimental and clinical data suggest a tight link between hearing and cognitive functions under both physiological and pathological conditions. Indeed, hearing perception requires high-level cognitive processes, and its alterations have been considered a risk factor for cognitive decline. Thus, identifying common pathogenic determinants of hearing loss and neurodegenerative disease is challenging. Here, we focused on redox status imbalance as a possible common pathological mechanism linking hearing and cognitive dysfunctions. Oxidative stress plays a critical role in cochlear damage occurring during aging, as well as in that induced by exogenous factors, including noise. At the same time, increased oxidative stress in medio-temporal brain regions, including the hippocampus, is a hallmark of neurodegenerative disorders like Alzheimer's disease. As such, antioxidant therapy seems to be a promising approach to prevent and/or counteract both sensory and cognitive neurodegeneration. Here, we review experimental evidence suggesting that redox imbalance is a key pathogenetic factor underlying the association between sensorineural hearing loss and neurodegenerative diseases. A greater understanding of the pathophysiological mechanisms shared by these two diseased conditions will hopefully provide relevant information to develop innovative and effective therapeutic strategies.
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Affiliation(s)
- Fabiola Paciello
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | - Cristian Ripoli
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
- Correspondence: ; Tel.: +39-0630154966
| | - Anna Rita Fetoni
- Unit of Audiology, Department of Neuroscience, Università degli Studi di Napoli Federico II, 80138 Naples, Italy
| | - Claudio Grassi
- Department of Neuroscience, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
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Mitochondrial Complex I Disruption Causes Broad Reorchestration of Plant Lipidome Including Chloroplast Lipids. Int J Mol Sci 2022; 24:ijms24010453. [PMID: 36613895 PMCID: PMC9820630 DOI: 10.3390/ijms24010453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/28/2022] [Accepted: 12/09/2022] [Indexed: 12/29/2022] Open
Abstract
Mitochondrial complex I (CI) plays a crucial role in oxidising NADH generated by the metabolism (including photorespiration) and thereby participates in the mitochondrial electron transfer chain feeding oxidative phosphorylation that generates ATP. However, CI mutations are not lethal in plants and cause moderate phenotypes, and therefore CI mutants are instrumental to examine consequences of mitochondrial homeostasis disturbance on plant cell metabolisms and signalling. To date, the consequences of CI disruption on the lipidome have not been examined. Yet, in principle, mitochondrial dysfunction should impact on lipid synthesis through chloroplasts (via changes in photorespiration, redox homeostasis, and N metabolism) and the endoplasmic reticulum (ER) (via perturbed mitochondrion-ER crosstalk). Here, we took advantage of lipidomics technology (by LC-MS), phospholipid quantitation by 31P-NMR, and total lipid quantitation to assess the impact of CI disruption on leaf, pollen, and seed lipids using three well-characterised CI mutants: CMSII in N. sylvestris and both ndufs4 and ndufs8 in Arabidopsis. Our results show multiple changes in cellular lipids, including galactolipids (chloroplastic), sphingolipids, and ceramides (synthesised by ER), suggesting that mitochondrial homeostasis is essential for the regulation of whole cellular lipidome via specific signalling pathways. In particular, the observed modifications in phospholipid and sphingolipid/ceramide molecular species suggest that CI activity controls phosphatidic acid-mediated signalling.
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Apparoo Y, Phan CW, Kuppusamy UR, Sabaratnam V. Ergothioneine and its prospects as an anti-ageing compound. Exp Gerontol 2022; 170:111982. [PMID: 36244584 DOI: 10.1016/j.exger.2022.111982] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 10/03/2022] [Accepted: 10/10/2022] [Indexed: 12/29/2022]
Abstract
Healthy ageing is a crucial process that needs to be highlighted as it affects the quality of lifespan. An increase in oxidative stress along with ageing is the major factor related to the age-associated diseases, especially neurodegenerative disorders. An antioxidant-rich diet has been proven to play a significant role in the ageing process. Targeting ageing mechanisms could be a worthwhile approach to improving health standards. Ergothioneine (EGT), a hydrophilic compound with specific transporter known as OCTN1, has been shown to exert anti-ageing properties. In addition to its antioxidant effect, EGT has been reported to have anti-senescence, anti-inflammatory and anti-neurodegenerative properties. This review aims to define the pivotal role of EGT in major signalling pathways in ageing such as insulin/insulin-like growth factor (IGF) signalling (IIS), sirtuin 6 (SIRT6) and mammalian target of rapamycin complex (mTOR) pathways. The review further discusses evidence of EGT on neurodegeneration in its therapeutic context in various model organisms, providing new insights into improving health. In conclusion, an ergothioneine-rich diet may be beneficial in preventing age-related diseases, resulting in a healthy ageing population.
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Affiliation(s)
- Yasaaswini Apparoo
- Department of Pharmaceutical Life Sciences, Faculty of Pharmacy, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Chia Wei Phan
- Department of Pharmaceutical Life Sciences, Faculty of Pharmacy, Universiti Malaya, 50603 Kuala Lumpur, Malaysia; Clinical Investigation Centre (CIC), 5th Floor, East Tower, University Malaya Medical Centre, 59100 Lembah Pantai Kuala Lumpur, Malaysia; Mushroom Research Centre, Universiti Malaya, 50603 Kuala Lumpur, Malaysia.
| | - Umah Rani Kuppusamy
- Department of Biomedical Science, Faculty of Medicine, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
| | - Vikneswary Sabaratnam
- Mushroom Research Centre, Universiti Malaya, 50603 Kuala Lumpur, Malaysia; Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603 Kuala Lumpur, Malaysia
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Bazard P, Pineros J, Frisina RD, Bauer MA, Acosta AA, Paganella LR, Borakiewicz D, Thivierge M, Mannering FL, Zhu X, Ding B. Cochlear Inflammaging in Relation to Ion Channels and Mitochondrial Functions. Cells 2021; 10:2761. [PMID: 34685743 PMCID: PMC8534887 DOI: 10.3390/cells10102761] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/06/2021] [Accepted: 10/12/2021] [Indexed: 12/20/2022] Open
Abstract
The slow accumulation of inflammatory biomarker levels in the body-also known as inflammaging-has been linked to a myriad of age-related diseases. Some of these include neurodegenerative conditions such as Parkinson's disease, obesity, type II diabetes, cardiovascular disease, and many others. Though a direct correlation has not been established, research connecting age-related hearing loss (ARHL)-the number one communication disorder and one of the most prevalent neurodegenerative diseases of our aged population-and inflammaging has gained interest. Research, thus far, has found that inflammatory markers, such as IL-6 and white blood cells, are associated with ARHL in humans and animals. Moreover, studies investigating ion channels and mitochondrial involvement have shown promising relationships between their functions and inflammaging in the cochlea. In this review, we summarize key findings in inflammaging within the auditory system, the involvement of ion channels and mitochondrial functions, and lastly discuss potential treatment options focusing on controlling inflammation as we age.
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Affiliation(s)
- Parveen Bazard
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (J.P.); (M.A.B.); (A.A.A.); (L.R.P.); (D.B.); (M.T.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA;
| | - Jennifer Pineros
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (J.P.); (M.A.B.); (A.A.A.); (L.R.P.); (D.B.); (M.T.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA;
| | - Robert D. Frisina
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (J.P.); (M.A.B.); (A.A.A.); (L.R.P.); (D.B.); (M.T.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA;
- Department Communication Sciences and Disorders, College of Behavioral & Communication Sciences, Tampa, FL 33620, USA
- Morsani College of Medicine, University of South Florida, Tampa, FL 33620, USA
| | - Mark A. Bauer
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (J.P.); (M.A.B.); (A.A.A.); (L.R.P.); (D.B.); (M.T.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA;
| | - Alejandro A. Acosta
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (J.P.); (M.A.B.); (A.A.A.); (L.R.P.); (D.B.); (M.T.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA;
| | - Lauren R. Paganella
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (J.P.); (M.A.B.); (A.A.A.); (L.R.P.); (D.B.); (M.T.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA;
| | - Dominika Borakiewicz
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (J.P.); (M.A.B.); (A.A.A.); (L.R.P.); (D.B.); (M.T.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA;
| | - Mark Thivierge
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (J.P.); (M.A.B.); (A.A.A.); (L.R.P.); (D.B.); (M.T.); (X.Z.); (B.D.)
- Morsani College of Medicine, University of South Florida, Tampa, FL 33620, USA
| | - Freyda L. Mannering
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA;
- Morsani College of Medicine, University of South Florida, Tampa, FL 33620, USA
| | - Xiaoxia Zhu
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (J.P.); (M.A.B.); (A.A.A.); (L.R.P.); (D.B.); (M.T.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA;
| | - Bo Ding
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (J.P.); (M.A.B.); (A.A.A.); (L.R.P.); (D.B.); (M.T.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA;
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Morciano G, Vitto VAM, Bouhamida E, Giorgi C, Pinton P. Mitochondrial Bioenergetics and Dynamism in the Failing Heart. Life (Basel) 2021; 11:life11050436. [PMID: 34066065 PMCID: PMC8151847 DOI: 10.3390/life11050436] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/07/2021] [Accepted: 05/07/2021] [Indexed: 12/13/2022] Open
Abstract
The heart is responsible for pumping blood, nutrients, and oxygen from its cavities to the whole body through rhythmic and vigorous contractions. Heart function relies on a delicate balance between continuous energy consumption and generation that changes from birth to adulthood and depends on a very efficient oxidative metabolism and the ability to adapt to different conditions. In recent years, mitochondrial dysfunctions were recognized as the hallmark of the onset and development of manifold heart diseases (HDs), including heart failure (HF). HF is a severe condition for which there is currently no cure. In this condition, the failing heart is characterized by a disequilibrium in mitochondrial bioenergetics, which compromises the basal functions and includes the loss of oxygen and substrate availability, an altered metabolism, and inefficient energy production and utilization. This review concisely summarizes the bioenergetics and some other mitochondrial features in the heart with a focus on the features that become impaired in the failing heart.
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Affiliation(s)
- Giampaolo Morciano
- Maria Cecilia Hospital, GVM Care&Research, 48033 Cotignola, Italy
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; (V.A.M.V.); (E.B.); (C.G.)
- Correspondence: (G.M.); (P.P.)
| | - Veronica Angela Maria Vitto
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; (V.A.M.V.); (E.B.); (C.G.)
| | - Esmaa Bouhamida
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; (V.A.M.V.); (E.B.); (C.G.)
| | - Carlotta Giorgi
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; (V.A.M.V.); (E.B.); (C.G.)
| | - Paolo Pinton
- Maria Cecilia Hospital, GVM Care&Research, 48033 Cotignola, Italy
- Laboratory for Technologies of Advanced Therapies (LTTA), Section of Experimental Medicine, Department of Medical Sciences, University of Ferrara, 44121 Ferrara, Italy; (V.A.M.V.); (E.B.); (C.G.)
- Correspondence: (G.M.); (P.P.)
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Panuzzo C, Jovanovski A, Pergolizzi B, Pironi L, Stanga S, Fava C, Cilloni D. Mitochondria: A Galaxy in the Hematopoietic and Leukemic Stem Cell Universe. Int J Mol Sci 2020; 21:ijms21113928. [PMID: 32486249 PMCID: PMC7312164 DOI: 10.3390/ijms21113928] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/24/2020] [Accepted: 05/28/2020] [Indexed: 12/17/2022] Open
Abstract
Mitochondria are the main fascinating energetic source into the cells. Their number, shape, and dynamism are controlled by the cell’s type and current behavior. The perturbation of the mitochondrial inward system via stress response and/or oncogenic insults could activate several trafficking molecular mechanisms with the intention to solve the problem. In this review, we aimed to clarify the crucial pathways in the mitochondrial system, dissecting the different metabolic defects, with a special emphasis on hematological malignancies. We investigated the pivotal role of mitochondria in the maintenance of hematopoietic stem cells (HSCs) and their main alterations that could induce malignant transformation, culminating in the generation of leukemic stem cells (LSCs). In addition, we presented an overview of LSCs mitochondrial dysregulated mechanisms in terms of (1) increasing in oxidative phosphorylation program (OXPHOS), as a crucial process for survival and self-renewal of LSCs,(2) low levels of reactive oxygen species (ROS), and (3) aberrant expression of B-cell lymphoma 2 (Bcl-2) with sustained mitophagy. Furthermore, these peculiarities may represent attractive new “hot spots” for mitochondrial-targeted therapy. Finally, we remark the potential of the LCS metabolic effectors to be exploited as novel therapeutic targets.
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Affiliation(s)
- Cristina Panuzzo
- Department of Clinical and Biological Sciences, University of Turin, 10043 Orbassano, Italy; (A.J.); (B.P.); (L.P.); (C.F.)
- Correspondence: (C.P.); (D.C.)
| | - Aleksandar Jovanovski
- Department of Clinical and Biological Sciences, University of Turin, 10043 Orbassano, Italy; (A.J.); (B.P.); (L.P.); (C.F.)
| | - Barbara Pergolizzi
- Department of Clinical and Biological Sciences, University of Turin, 10043 Orbassano, Italy; (A.J.); (B.P.); (L.P.); (C.F.)
| | - Lucrezia Pironi
- Department of Clinical and Biological Sciences, University of Turin, 10043 Orbassano, Italy; (A.J.); (B.P.); (L.P.); (C.F.)
| | - Serena Stanga
- Department of Neuroscience Rita Levi Montalcini, 10124 Turin, Italy;
- Neuroscience Institute Cavalieri Ottolenghi, University of Turin, 10043 Orbassano, Italy
| | - Carmen Fava
- Department of Clinical and Biological Sciences, University of Turin, 10043 Orbassano, Italy; (A.J.); (B.P.); (L.P.); (C.F.)
| | - Daniela Cilloni
- Department of Clinical and Biological Sciences, University of Turin, 10043 Orbassano, Italy; (A.J.); (B.P.); (L.P.); (C.F.)
- Correspondence: (C.P.); (D.C.)
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Dikova V, Vorhauser J, Geng A, Pelster B, Sandbichler AM. Metabolic interaction of hydrogen peroxide and hypoxia in zebrafish fibroblasts. Free Radic Biol Med 2020; 152:469-481. [PMID: 31740229 DOI: 10.1016/j.freeradbiomed.2019.11.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 11/12/2019] [Accepted: 11/12/2019] [Indexed: 11/26/2022]
Abstract
Cells require oxygen for aerobic metabolism, which may also result in the production of reactive oxygen species (ROS) as a by-product. Under low oxygen conditions, ROS formation has been reported to either increase or decrease. We addressed this physiological response for the first time in zebrafish embryonic fibroblasts (Z3) and used a hydrogen peroxide (H2O2)-specific fluorescent protein (roGFP2-Orp1) either targeted to the mitochondria or expressed in the cytosol. Microfluidic live-cell imaging measurements showed that oxygen deprivation in Z3 cells results in decreased or stable H2O2 levels within the mitochondria or the cytosol, respectively, and that the reductive shift recorded in the mitochondrial matrix is directly dependent on oxygen concentration. The response was accompanied by a transient increase in extracellular acidification rate (ECAR) and a lower cellular reducing potential as assessed by the viability stain alamarBlue. Complex I and III inhibition with Rotenone and Antimycin A led to H2O2 production under normoxia but these inhibitors were not able to avert the reductive shift under hypoxia. Only by system-wide inhibition of flavin-containing oxidases with Diphenyleneiodonium (DPI) were we able to decrease the reductive shift, while selective inhibition of NADPH oxidases with the inhibitor Apocynin had no effect on the hypoxia response. Since DPI also led to a strong increase in ECAR we found that, in order to keep the cytosolic H2O2 levels stable, glycolytic metabolism was of fundamental importance. According to our experiments with the glucose-6-phosphate dehydrogenase inhibitor 6-Aminonicotinamide, this was attributable to the pentose phosphate pathway producing reducing equivalents required for ROS degradation.
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Affiliation(s)
- Valentina Dikova
- Institute of Zoology and Center for Molecular Biosciences (CMBI), University of Innsbruck, Austria
| | - Julia Vorhauser
- Institute of Zoology and Center for Molecular Biosciences (CMBI), University of Innsbruck, Austria
| | - Anne Geng
- Institute of Zoology and Center for Molecular Biosciences (CMBI), University of Innsbruck, Austria
| | - Bernd Pelster
- Institute of Zoology and Center for Molecular Biosciences (CMBI), University of Innsbruck, Austria
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The alterations of mitochondrial DNA in coronary heart disease. Exp Mol Pathol 2020; 114:104412. [PMID: 32113905 DOI: 10.1016/j.yexmp.2020.104412] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 02/24/2020] [Accepted: 02/27/2020] [Indexed: 12/17/2022]
Abstract
Coronary heart disease (CHD) is the major cause of death in modern society. CHD is characterized by atherosclerosis, which could lead to vascular cavity stenosis or obstruction, resulting in ischemic cardiac conditions such as angina and myocardial infarction. In terms of the mitochondrion, the main function is to produce adenosine triphosphate (ATP) for cells. And the alterations (including mutations, altered copy number and haplogroups) of mitochondrial DNA (mtDNA) are associated with the abnormal expression of oxidative phosphorylation (OXPHOS) system, resulting in mitochondrial dysfunction, then leading to perturbation on the electron transport chain and increased ROS generation and reduction in ATP level, contributing to ATP-producing disorders and oxidative stress, which may further accelerate development or vulnerability of atherosclerosis and myocardial ischemic injury. Therefore, the mtDNA defects may play an important role in making an early diagnosis, identifying disease-specific biomarkers and therapeutic targets, and predicting outcomes for patients with atherosclerosis and CHD. In this review, we aim to summarize the contribution of mtDNA mutations, altered mtDNA copy number and mtDNA haplogroups on the occurrence and development of CHD.
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Ruden JB, Quick KL, Gonzales ER, Shah AR, Park TS, Kennedy N, Dugan LL, Gidday JM. Reduction of Leukocyte Microvascular Adherence and Preservation of Blood-Brain Barrier Function by Superoxide-Lowering Therapies in a Piglet Model of Neonatal Asphyxia. Front Neurol 2019; 10:447. [PMID: 31118919 PMCID: PMC6504682 DOI: 10.3389/fneur.2019.00447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/12/2019] [Indexed: 11/13/2022] Open
Abstract
Background: Asphyxia is the most common cause of brain damage in newborns. Substantial evidence indicates that leukocyte recruitment in the cerebral vasculature during asphyxia contributes to this damage. We tested the hypothesis that superoxide radical (O 2 ⋅ _ ) promotes an acute post-asphyxial inflammatory response and blood-brain barrier (BBB) breakdown. We investigated the effects of removingO 2 ⋅ _ by superoxide dismutase (SOD) or C3, the cell-permeable SOD mimetic, in protecting against asphyxia-related leukocyte recruitment. We also tested the hypothesis that xanthine oxidase activity is one source of this radical. Methods: Anesthetized piglets were tracheostomized, ventilated, and equipped with closed cranial windows for the assessment of post-asphyxial rhodamine 6G-labeled leukocyte-endothelial adherence and microvascular permeability to sodium fluorescein in cortical venules. Asphyxia was induced by discontinuing ventilation. SOD and C3 were administered by cortical superfusion. The xanthine oxidase inhibitor oxypurinol was administered intravenously. Results: Leukocyte-venular adherence significantly increased during the initial 2 h of post-asphyxial reperfusion. BBB permeability was also elevated relative to non-asphyxial controls. Inhibition ofO 2 ⋅ _ production by oxypurinol, or elimination ofO 2 ⋅ _ by SOD or C3, significantly reduced rhodamine 6G-labeled leukocyte-endothelial adherence and improved BBB integrity, as measured by sodium fluorescein leak from cerebral microvessels. Conclusion: Using three different strategies to either prevent formation or enhance elimination ofO 2 ⋅ _ during the post-asphyxial period, we saw both reduced leukocyte adherence and preserved BBB function with treatment. These findings suggest that agents which lowerO 2 ⋅ _ in brain may be attractive new therapeutic interventions for the protection of the neonatal brain following asphyxia.
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Affiliation(s)
- Jacob B. Ruden
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
| | | | - Ernesto R. Gonzales
- Hope Center for Neurological Disorders and Department of Neurology, Washington University in Saint Louis School of Medicine, St. Louis, MO, United States
| | - Aarti R. Shah
- Hope Center for Neurological Disorders and Department of Neurology, Washington University in Saint Louis School of Medicine, St. Louis, MO, United States
- Knight Alzheimer's Disease Research Center, Washington University in Saint Louis School of Medicine, St. Louis, MO, United States
| | - T. S. Park
- Department of Neurosurgery, St. Louis Children's Hospital, Washington University in Saint Louis School of Medicine, St. Louis, MO, United States
| | - Nan Kennedy
- Vanderbilt Institute for Clinical and Translational Research, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Laura L. Dugan
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
- Division of Geriatric Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Jeffrey M. Gidday
- Departments of Ophthalmology, Physiology, and Neuroscience, Louisiana State University School of Medicine, New Orleans, LA, United States
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12
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Tawfik KO, Klepper K, Saliba J, Friedman RA. Advances in understanding of presbycusis. J Neurosci Res 2019; 98:1685-1697. [PMID: 30950547 DOI: 10.1002/jnr.24426] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 03/14/2019] [Accepted: 03/18/2019] [Indexed: 12/21/2022]
Abstract
The pathophysiology of age-related hearing loss (ARHL), or presbycusis, involves a complex interplay between environmental and genetic factors. The fundamental biomolecular mechanisms of ARHL have been well described, including the roles of membrane transport, reactive oxygen species, cochlear synaptopathy, vascular insults, hormones, and microRNA, to name a few. The genetic basis underlying these mechanisms remains under-investigated and poorly understood. The emergence of genome-wide association studies has allowed for the identification of specific groups of genes involved in ARHL. This review highlights recent advances in understanding of the pathogenesis of ARHL, the genetic basis underlying these processes and suggests future directions for research and potential therapeutic avenues.
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Affiliation(s)
- Kareem O Tawfik
- Division of Otolaryngology - Head & Neck Surgery, University of California San Diego School of Medicine, San Diego, California
| | - Kristin Klepper
- School of Medicine, University of California San Diego, La Jolla, California
| | - Joe Saliba
- Division of Otolaryngology - Head & Neck Surgery, University of California San Diego School of Medicine, San Diego, California
| | - Rick A Friedman
- Division of Otolaryngology - Head & Neck Surgery, University of California San Diego School of Medicine, San Diego, California
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13
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Tu NC, Friedman RA. Age-related hearing loss: Unraveling the pieces. Laryngoscope Investig Otolaryngol 2018; 3:68-72. [PMID: 29721536 PMCID: PMC5915820 DOI: 10.1002/lio2.134] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/06/2017] [Accepted: 12/04/2017] [Indexed: 01/23/2023] Open
Abstract
Age-related hearing loss (ARHL) is the most common cause of hearing loss in the world. The development of ARHL in each individual is multifactorial, involving both intrinsic and extrinsic factors. This review highlights several of the key findings in the ARHL literature and discusses future directions. LEVEL OF EVIDENCE NA.
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Affiliation(s)
- Nathan C. Tu
- Tina and Rick Caruso Department of Otolaryngology–Head and Neck Surgery (N.C.T., R.A.F.)Keck School of Medicine of the University of Southern CaliforniaLos AngelesCaliforniaU.S.A.
| | - Rick A. Friedman
- Tina and Rick Caruso Department of Otolaryngology–Head and Neck Surgery (N.C.T., R.A.F.)Keck School of Medicine of the University of Southern CaliforniaLos AngelesCaliforniaU.S.A.
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14
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Vallard A, Rancoule C, Guy JB, Espenel S, Sauvaigo S, Rodriguez-Lafrasse C, Magné N. [Biomarkers of radiation-induced DNA repair processes]. Bull Cancer 2017; 104:981-987. [PMID: 29132682 DOI: 10.1016/j.bulcan.2017.09.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 09/21/2017] [Indexed: 12/18/2022]
Abstract
The identification of DNA repair biomarkers is of paramount importance. Indeed, it is the first step in the process of modulating radiosensitivity and radioresistance. Unlike tools of detection and measurement of DNA damage, DNA repair biomarkers highlight the variations of DNA damage responses, depending on the dose and the dose rate. The aim of the present review is to describe the main biomarkers of radiation-induced DNA repair. We will focus on double strand breaks (DSB), because of their major role in radiation-induced cell death. The most important DNA repair biomarkers are DNA damage signaling proteins, with ATM, DNA-PKcs, 53BP1 and γ-H2AX. They can be analyzed either using immunostaining, or using lived cell imaging. However, to date, these techniques are still time and money consuming. The development of "omics" technologies should lead the way to new (and usable in daily routine) DNA repair biomarkers.
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Affiliation(s)
- Alexis Vallard
- Institut de cancérologie Lucien-Neuwirth, département de radiothérapie, , 108, bis avenue Albert-Raimond, BP60008, 42271 Saint-Priest-en-Jarez cedex, France; Institut de physique nucléaire de Lyon, IPNL, CNRS-UMR-5822, laboratoire de radiobiologie cellulaire et moléculaire, 69622 Villeurbanne, France
| | - Chloé Rancoule
- Institut de cancérologie Lucien-Neuwirth, département de radiothérapie, , 108, bis avenue Albert-Raimond, BP60008, 42271 Saint-Priest-en-Jarez cedex, France; Institut de physique nucléaire de Lyon, IPNL, CNRS-UMR-5822, laboratoire de radiobiologie cellulaire et moléculaire, 69622 Villeurbanne, France
| | - Jean-Baptiste Guy
- Institut de cancérologie Lucien-Neuwirth, département de radiothérapie, , 108, bis avenue Albert-Raimond, BP60008, 42271 Saint-Priest-en-Jarez cedex, France; Institut de physique nucléaire de Lyon, IPNL, CNRS-UMR-5822, laboratoire de radiobiologie cellulaire et moléculaire, 69622 Villeurbanne, France
| | - Sophie Espenel
- Institut de cancérologie Lucien-Neuwirth, département de radiothérapie, , 108, bis avenue Albert-Raimond, BP60008, 42271 Saint-Priest-en-Jarez cedex, France; Institut de physique nucléaire de Lyon, IPNL, CNRS-UMR-5822, laboratoire de radiobiologie cellulaire et moléculaire, 69622 Villeurbanne, France
| | | | - Claire Rodriguez-Lafrasse
- Institut de physique nucléaire de Lyon, IPNL, CNRS-UMR-5822, laboratoire de radiobiologie cellulaire et moléculaire, 69622 Villeurbanne, France
| | - Nicolas Magné
- Institut de cancérologie Lucien-Neuwirth, département de radiothérapie, , 108, bis avenue Albert-Raimond, BP60008, 42271 Saint-Priest-en-Jarez cedex, France; Institut de physique nucléaire de Lyon, IPNL, CNRS-UMR-5822, laboratoire de radiobiologie cellulaire et moléculaire, 69622 Villeurbanne, France.
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15
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Cheng Z, Peng HL, Zhang R, Fu XM, Zhang GS. Rejuvenation of Cardiac Tissue Developed from Reprogrammed Aged Somatic Cells. Rejuvenation Res 2017; 20:389-400. [PMID: 28478705 DOI: 10.1089/rej.2017.1930] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Induced pluripotent stem cells (iPSCs) derived via somatic cell reprogramming have been reported to reset aged somatic cells to a more youthful state, characterized by elongated telomeres, a rearranged mitochondrial network, reduced oxidative stress, and restored pluripotency. However, it is still unclear whether the reprogrammed aged somatic cells can function normally as embryonic stem cells (ESCs) during development and be rejuvenated. In the current study, we applied the aggregation technique to investigate whether iPSCs derived from aged somatic cells could develop normally and be rejuvenated. iPSCs derived from bone marrow myeloid cells of 2-month-old (2 M) and 18-month-old (18 M) C57BL/6-Tg (CAG-EGFP)1Osb/J mice were aggregated with embryos derived from wild-type ICR mice to produce chimeras (referred to as 2 M CA and 18 M CA, respectively). Our observations focused on comparing the ability of the iPSCs derived from 18 M and 2 M bone marrow cells to develop rejuvenated cardiac tissue (the heart is the most vital organ during aging). The results showed an absence of p16 and p53 upregulation, telomere length shortening, and mitochondrial gene expression and deletion in 18 M CA, whereas slight changes in mitochondrial ultrastructure, cytochrome C oxidase activity, ATP production, and reactive oxygen species production were observed in CA cardiac tissues. The data implied that all of the aging characteristics observed in the newborn cardiac tissue of 18 M CA were comparable with those of 2 M CA newborn cardiac tissue. This study provides the first direct evidence of the aging-related characteristics of cardiac tissue developed from aged iPSCs, and our observations demonstrate that partial rejuvenation can be achieved by reprogramming aged somatic cells to a pluripotent state.
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Affiliation(s)
- Zhao Cheng
- 1 Department of Hematology, Institute of Molecular Hematology, The Second Xiang-ya Hospital, Central South University , Changsha, People's Republic of China
| | - Hong-Ling Peng
- 1 Department of Hematology, Institute of Molecular Hematology, The Second Xiang-ya Hospital, Central South University , Changsha, People's Republic of China
| | - Rong Zhang
- 2 Division of Cancer Immunotherapy, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center , Kashiwanoha, Kashiwa, Japan
| | - Xian-Ming Fu
- 3 Department of Cardiac Surgery, The Second Xiang-ya Hospital, Central South University , Changsha, People's Republic of China
| | - Guang-Sen Zhang
- 1 Department of Hematology, Institute of Molecular Hematology, The Second Xiang-ya Hospital, Central South University , Changsha, People's Republic of China
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16
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Moreno-Loshuertos R, Enríquez JA. Respiratory supercomplexes and the functional segmentation of the CoQ pool. Free Radic Biol Med 2016; 100:5-13. [PMID: 27105951 DOI: 10.1016/j.freeradbiomed.2016.04.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 04/15/2016] [Accepted: 04/17/2016] [Indexed: 12/14/2022]
Abstract
The evidence accumulated during the last fifteen years on the existence of respiratory supercomplexes and their proposed functional implications has changed our understanding of the OXPHOS system complexity and regulation. The plasticity model is a point of encounter accounting for the apparently contradictory experimental observations claimed to support either the solid or the fluid models. It allows the explanation of previous observations such as the dependence between respiratory complexes, supercomplex assembly dynamics or the existence of different functional ubiquinone pools. With the general acceptation of respiratory supercomplexes as true entities, this review evaluates the supporting evidences in favor or against the existence of different ubiquinone pools and the relationship between supercomplexes, ROS production and pathology.
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Affiliation(s)
- Raquel Moreno-Loshuertos
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna, 12, Zaragoza 50009, Spain
| | - José Antonio Enríquez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III, Melchor Fernández Almagro, 3, 28029 Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Pedro Cerbuna, 12, Zaragoza 50009, Spain.
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17
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Porras CAM, Bai Y. Respiratory supercomplexes: plasticity and implications. Front Biosci (Landmark Ed) 2015; 20:621-34. [PMID: 25553469 DOI: 10.2741/4327] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The plasticity model of the electron transport chain has slowly begun to replace both the liquid model of free complexes and the solid model of supercomplexes. The plasticity model predicts that respiratory complexes exist and function both as single complexes and as supercomplexes. The advantages of this system is an electron transport train which is able to adapt to changes in its environment. This review will investigate the current body of work on supercomplexes including their assembly, regulation, and plasticity, and particularly their role in the generation of reactive oxygen species and aging.
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Affiliation(s)
- Christina Ann-Marie Porras
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Yidong Bai
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
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18
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Sobenin IA, Zhelankin AV, Sinyov VV, Bobryshev YV, Orekhov AN. Mitochondrial Aging: Focus on Mitochondrial DNA Damage in Atherosclerosis - A Mini-Review. Gerontology 2014; 61:343-9. [DOI: 10.1159/000368923] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 10/08/2014] [Indexed: 11/19/2022] Open
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19
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Melis JPM, Jonker MJ, Vijg J, Hoeijmakers JHJ, Breit TM, van Steeg H. Aging on a different scale--chronological versus pathology-related aging. Aging (Albany NY) 2014; 5:782-8. [PMID: 24131799 PMCID: PMC3838780 DOI: 10.18632/aging.100606] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In the next decades the elderly population will increase dramatically, demanding appropriate solutions in health care and aging research focusing on healthy aging to prevent high burdens and costs in health care. For this, research targeting tissue-specific and individual aging is paramount to make the necessary progression in aging research. In a recently published study we have attempted to make a step interpreting aging data on chronological as well as pathological scale. For this, we sampled five major tissues at regular time intervals during the entire C57BL/6J murine lifespan from a controlled in vivo aging study, measured the whole transcriptome and incorporated temporal as well as physical health aspects into the analyses. In total, we used 18 different age-related pathological parameters and transcriptomic profiles of liver, kidney, spleen, lung and brain and created a database that can now be used for a broad systems biology approach. In our study, we focused on the dynamics of biological processes during chronological aging and the comparison between chronological and pathology-related aging.
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Affiliation(s)
- Joost P M Melis
- National Institute for Public Health and the Environment (RIVM), Center for Health Protection, Bilthoven, the Netherlands
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20
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Comegna M, Succoio M, Napolitano M, Vitale M, D'Ambrosio C, Scaloni A, Passaro F, Zambrano N, Cimino F, Faraonio R. Identification of miR-494 direct targets involved in senescence of human diploid fibroblasts. FASEB J 2014; 28:3720-33. [PMID: 24823364 DOI: 10.1096/fj.13-239129] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Cellular senescence is a permanent cell cycle arrest triggered by different stimuli. We recently identified up-regulation of microRNA (miR)-494 as a component of the genetic program leading to senescence of human diploid IMR90 fibroblasts. Here, we used 2-dimensional differential gel electrophoresis (2D-DIGE) coupled to mass spectrometry to profile protein expression changes induced by adoptive overexpression of miR-494 in IMR90 cells. miR-494 induced robust perturbation of the IMR90 proteome by significantly (P≤0.05) down-regulating a number of proteins. Combination of mass spectrometry-based identification of down-regulated proteins and bioinformatic prediction of the miR-494 binding sites on the relevant mRNAs identified 26 potential targets of miR-494. Among them, computational analysis identified 7 potential evolution-conserved miR-494 targets. Functional miR-494 binding sites were confirmed in 3'-untranslated regions (UTRs) of 4 of them [heterogeneous nuclear ribonucleoprotein A3 (hnRNPA3), protein disulfide isomerase A3 (PDIA3), UV excision repair protein RAD23 homolog B (RAD23B), and synaptotagmin-binding cytoplasmic RNA-interacting protein (SYNCRIP)/heterogeneous nuclear ribonucleoprotein Q (hnRNPQ)]. Their reduced expression correlated with miR-494 up-regulation in senescent cells. RNA interference-mediated knockdown of hnRNPA3 and, to a lesser extent, RAD23B mirrored the senescent phenotype induced by miR-494 overexpression, blunting cell proliferation and causing up-regulation of SA-β-galactosidase and DNA damage. Ectopic expression of hnRNPA3 or RAD23B slowed the appearance of the senescent phenotype induced by miR-494. Overall, these findings identify novel miR-494 direct targets that are involved in cellular senescence.
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Affiliation(s)
- Marika Comegna
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy; Center of Genetics Engineering (CEINGE) Biotecnologie Avanzate s.c. a r.l, Naples, Italy; and
| | - Mariangela Succoio
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy; Center of Genetics Engineering (CEINGE) Biotecnologie Avanzate s.c. a r.l, Naples, Italy; and
| | - Marco Napolitano
- Fondazione SDN, Istituto di Ricerca Diagnostica e Nucleare, Naples, Italy
| | - Monica Vitale
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy; Center of Genetics Engineering (CEINGE) Biotecnologie Avanzate s.c. a r.l, Naples, Italy; and
| | - Chiara D'Ambrosio
- Proteomics and Mass Spectrometry Laboratory, National Research Council, Naples, Italy
| | - Andrea Scaloni
- Proteomics and Mass Spectrometry Laboratory, National Research Council, Naples, Italy
| | - Fabiana Passaro
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy; Fondazione SDN, Istituto di Ricerca Diagnostica e Nucleare, Naples, Italy; Center of Genetics Engineering (CEINGE) Biotecnologie Avanzate s.c. a r.l, Naples, Italy; and
| | - Nicola Zambrano
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy; Center of Genetics Engineering (CEINGE) Biotecnologie Avanzate s.c. a r.l, Naples, Italy; and
| | - Filiberto Cimino
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy; Fondazione SDN, Istituto di Ricerca Diagnostica e Nucleare, Naples, Italy; Center of Genetics Engineering (CEINGE) Biotecnologie Avanzate s.c. a r.l, Naples, Italy; and
| | - Raffaella Faraonio
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy; Center of Genetics Engineering (CEINGE) Biotecnologie Avanzate s.c. a r.l, Naples, Italy; and
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21
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Electron Transport in the Mitochondrial Respiratory Chain. THE STRUCTURAL BASIS OF BIOLOGICAL ENERGY GENERATION 2014. [DOI: 10.1007/978-94-017-8742-0_21] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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22
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Cheng Z, Ito S, Nishio N, Thanasegaran S, Fang H, Isobe KI. Characteristics of cardiac aging in C57BL/6 mice. Exp Gerontol 2013; 48:341-8. [DOI: 10.1016/j.exger.2013.01.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 12/05/2012] [Accepted: 01/08/2013] [Indexed: 11/29/2022]
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Gasparre G, Porcelli AM, Lenaz G, Romeo G. Relevance of mitochondrial genetics and metabolism in cancer development. Cold Spring Harb Perspect Biol 2013; 5:5/2/a011411. [PMID: 23378588 DOI: 10.1101/cshperspect.a011411] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cancer cells are characterized in general by a decrease of mitochondrial respiration and oxidative phosphorylation, together with a strong enhancement of glycolysis, the so-called Warburg effect. The decrease of mitochondrial activity in cancer cells may have multiple reasons, related either to the input of reducing equivalents to the electron transfer chain or to direct alterations of the mitochondrial respiratory complexes. In some cases, the depression of respiratory activity is clearly the consequence of disruptive mitochondrial DNA (mtDNA) mutations and leads as a consequence to enhanced generation of reactive oxygen species (ROS). By acting both as mutagens and cellular mitogens, ROS may contribute directly to cancer progression. On the basis of our experimental evidence, we suggest a deep implication of the supercomplex organization of the respiratory chain as a missing link between oxidative stress, energy failure, and tumorigenesis. We speculate that under conditions of oxidative stress, a dissociation of mitochondrial supercomplexes occurs, with destabilization of complex I and secondary enhanced generation of ROS, thus leading to a vicious circle amplifying mitochondrial dysfunction. An excellent model to dissect the role of pathogenic, disassembling mtDNA mutations in tumor progression and their contribution to the metabolic reprogramming of cancer cells (glycolysis vs. respiration) is provided by an often underdiagnosed subset of tumors, namely, the oncocytomas, characterized by disruptive mutations of mtDNA, especially of complex I subunits. Such mutations almost completely abolish complex I activity, which slows down the Krebs cycle, favoring a high ratio of α-ketoglutarate/succinate and consequent destabilization of hypoxia inducible factor 1α (HIF1α). On the other hand, if complex I is partially defective, the levels of NAD(+) may be sufficient to implement the Krebs cycle with higher levels of intermediates that stabilize HIF1α, thus favoring tumor malignancy. The threshold model we propose, based on the population-like dynamics of mitochondrial genetics (heteroplasmy vs. homoplasmy), implies that below threshold complex I is present and functioning correctly, thus favoring tumor growth, whereas above threshold, when complex I is not assembled, tumor growth is arrested. We have therefore termed "oncojanus" the mtDNA genes whose disruptive mutations have such a double-edged effect.
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Affiliation(s)
- Giuseppe Gasparre
- Department of Medical and Surgical Sciences, Unit of Medical Genetics, University of Bologna Medical School, 40138 Bologna, Italy
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24
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The mitochondrion: a perpetrator of acquired hearing loss. Hear Res 2013; 303:12-9. [PMID: 23361190 DOI: 10.1016/j.heares.2013.01.006] [Citation(s) in RCA: 142] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 12/22/2012] [Accepted: 01/06/2013] [Indexed: 02/01/2023]
Abstract
Age, drugs, and noise are major causes of acquired hearing loss. The involvement of reactive oxygen species (ROS) in hair cell death has long been discussed, but there is considerably less information available as to the mechanisms underlying ROS formation. Most cellular ROS arise in mitochondria and this review will evaluate evidence for mitochondrial pathology in general and dysfunction of the mitochondrial respiratory chain in particular in acquired hearing loss. We will discuss evidence that different pathways can lead to the generation of ROS and that oxidative stress might not necessarily be causal to all three pathologies. Finally, we will detail recent advances in exploiting knowledge of aminoglycoside-mitochondria interactions for the development of non-ototoxic antibacterials. This article is part of a Special Issue entitled "Annual Reviews 2013".
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25
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Giannone FA, Treré D, Domenicali M, Grattagliano I, Baracca A, Sgarbi G, Maggioli C, Longobardi P, Solaini G, Derenzini M, Bernardi M, Caraceni P. An innovative hyperbaric hypothermic machine perfusion protects the liver from experimental preservation injury. ScientificWorldJournal 2012; 2012:573410. [PMID: 22593698 PMCID: PMC3345935 DOI: 10.1100/2012/573410] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 12/18/2011] [Indexed: 02/07/2023] Open
Abstract
Purpose. Hypothermic machine perfusion systems seem more effective than the current static storage to prevent cold ischemic liver injury. Thus, we test an innovative hyperbaric hypothermic machine perfusion (HHMP), which combines hyperbaric oxygenation of the preservation solution and continuous perfusion of the graft. Methods. Rat livers were preserved with Celsior solution according to 4 different modalities: normobaric static preservation; hyperbaric static preservation at 2 atmosphere absolute (ATA); normobaric dynamic preservation, with continuous perfusion; hyperbaric dynamic preservation, with continuous perfusion at 2 ATA. After 24 h cold preservation, we assessed different parameters. Results. Compared to baseline, livers preserved with the current static storage showed severe ultrastructural damage, glycogen depletion and an increased oxidative stress. Normobaric perfused livers showed improved hepatocyte ultrastructure and ameliorated glycogen stores, but they still suffered a significant oxidative damage. The addition of hyperbaric oxygen produces an extra benefit by improving oxidative injury and by inducing endothelial NO synthase (eNOS) gene expression. Conclusions. Preservation by means of the present innovative HHMP reduced the liver injury occurring after the current static cold storage by lowering glycogen depletion and oxidative damage. Interestingly, only the use of hyperbaric oxygen was associated to a blunted oxidative stress and an increased eNOS gene expression.
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Affiliation(s)
- Ferdinando A Giannone
- Department of Clinical Medicine, Alma Mater Studiorum University of Bologna, 40138 Bologna, Italy
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Lenaz G, Genova ML. Supramolecular Organisation of the Mitochondrial Respiratory Chain: A New Challenge for the Mechanism and Control of Oxidative Phosphorylation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:107-44. [DOI: 10.1007/978-1-4614-3573-0_5] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Lenaz G. Mitochondria and reactive oxygen species. Which role in physiology and pathology? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 942:93-136. [PMID: 22399420 DOI: 10.1007/978-94-007-2869-1_5] [Citation(s) in RCA: 139] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Oxidative stress is among the major causes of toxicity due to interaction of Reactive Oxygen Species (ROS) with cellular macromolecules and structures and interference with signal transduction pathways. The mitochondrial respiratory chain, specially from Complexes I and III, is considered the main origin of ROS particularly under conditions of high membrane potential, but several other sources may be important for ROS generation, such as mitochondrial p66(Shc), monoamine oxidase, α-ketoglutarate dehydogenase, besides redox cycling of redox-active molecules. ROS are able to oxidatively modify lipids, proteins, carbohydrates and nucleic acids in mitochondria and to activate/inactivate signalling pathways by oxidative modification of redox-active factors. Cells are endowed with several defence mechanisms including repair or removal of damaged molecules, and antioxidant systems, either enzymatic or non-enzymatic. Oxidative stress is at the basis of ageing and many pathological disorders, such as ischemic diseases, neurodegenerative diseases, diabetes, and cancer, although the underlying mechanisms are not always completely understood.
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Affiliation(s)
- Giorgio Lenaz
- Dipartimento di Biochimica, Università di Bologna, Bologna, Italy.
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Sgarbi G, Giannone F, Casalena GA, Baracca A, Baldassare M, Longobardi P, Caraceni P, Derenzini M, Lenaz G, Trerè D, Solaini G. Hyperoxia fully protects mitochondria of explanted livers. J Bioenerg Biomembr 2011; 43:673-82. [PMID: 22015484 DOI: 10.1007/s10863-011-9390-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2011] [Accepted: 09/28/2011] [Indexed: 12/18/2022]
Abstract
Liver ischemia-reperfusion injury is still an open problem in many clinical circumstances, including surgery and transplantation. This study investigates how mitochondrial structure, mass and oxidative phosphorylation change and may be preserved during a brief period of ischemia followed by a long period of reperfusion, an experimental model that mimics the condition to which a liver is exposed during transplantation. Livers were explanted from rats and exposed for 24 h to three different oxygen availability conditions at 4 °C. Mitochondrial mass, respiration, oxidative phosphorylation (OXPHOS), and levels of OXPHOS complexes were all significantly altered in livers stored under the currently used preservation condition of normoxia. Remarkably, liver perfusion with hyperoxic solutions fully preserved mitochondrial morphology and function, suggesting that perfusion of the graft with hyperoxic solution should be considered in human transplantation.
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Affiliation(s)
- G Sgarbi
- Department of Biochemistry, University of Bologna, Via Irnerio, 48, 40126, Bologna, Italy
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Picard M. Pathways to aging: the mitochondrion at the intersection of biological and psychosocial sciences. J Aging Res 2011; 2011:814096. [PMID: 21961065 PMCID: PMC3180824 DOI: 10.4061/2011/814096] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 05/11/2011] [Accepted: 07/11/2011] [Indexed: 01/10/2023] Open
Abstract
Compelling evidence suggests that both biological and psychosocial factors impact the process of aging. However, our understanding of the dynamic interplay among biological and psychosocial factors across the life course is still fragmentary. For example, it needs to be established how the interaction of individual factors (e.g., genetic and epigenetic endowment and personality), behavioral factors (e.g., physical activity, diet, and stress management), and psychosocial experiences (e.g., social support, well-being, socioeconomic status, and marriage) in perinatal, childhood, and adulthood influence health across the aging continuum. This paper aims to outline potential intersection points serving as an interface between biological and psychosocial factors, with an emphasis on the mitochondrion. Mitochondria are cellular organelles which play a critical role in cellular senescence. Both chronic exposure to psychosocial stress and genetic-based mitochondrial dysfunction have strikingly similar biological consequences; both predispose individuals to adverse age-related health disorders and early mortality. Exploring the interactive nature of the factors resulting in pathways to normal healthy aging, as well as those leading to morbidity and early mortality, will continue to enhance our ability to translate research into effective practices that can be implemented throughout the life course to optimise the aging process.
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Affiliation(s)
- Martin Picard
- Department of Kinesiology and Physical Education, McGill University, 475 Pine Avenue, Montreal, QC, Canada H2W 1S4
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Genova ML, Lenaz G. New developments on the functions of coenzyme Q in mitochondria. Biofactors 2011; 37:330-54. [PMID: 21989973 DOI: 10.1002/biof.168] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 04/06/2011] [Indexed: 12/12/2022]
Abstract
The notion of a mobile pool of coenzyme Q (CoQ) in the lipid bilayer has changed with the discovery of respiratory supramolecular units, in particular the supercomplex comprising complexes I and III; in this model, the electron transfer is thought to be mediated by tunneling or microdiffusion, with a clear kinetic advantage on the transfer based on random collisions. The CoQ pool, however, has a fundamental function in establishing a dissociation equilibrium with bound quinone, besides being required for electron transfer from other dehydrogenases to complex III. The mechanism of CoQ reduction by complex I is analyzed regarding recent developments on the crystallographic structure of the enzyme, also in relation to the capacity of complex I to generate superoxide. Although the mechanism of the Q-cycle is well established for complex III, involvement of CoQ in proton translocation by complex I is still debated. Some additional roles of CoQ are also examined, such as the antioxidant effect of its reduced form and the capacity to bind the permeability transition pore and the mitochondrial uncoupling proteins. Finally, a working hypothesis is advanced on the establishment of a vicious circle of oxidative stress and supercomplex disorganization in pathological states, as in neurodegeneration and cancer.
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Why are there no proven therapies for genetic mitochondrial diseases? Mitochondrion 2011; 11:679-85. [PMID: 21605707 DOI: 10.1016/j.mito.2011.05.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 04/04/2011] [Accepted: 05/05/2011] [Indexed: 12/13/2022]
Abstract
Although mitochondrial disease research in general is robust, adequate treatment of these life-threatening conditions has lagged, partly because of a persistence of clinical anecdotes as substitutes for scientifically and ethically rigorous clinical trials. Here I summarize the key lessons learned from some of the "first generation" of randomized controlled trials for genetic mitochondrial diseases and suggest how future trials may benefit from both past experience and exciting new resources available for patient-oriented research and training in this field.
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Smith BC, Settles B, Hallows WC, Craven MW, Denu JM. SIRT3 substrate specificity determined by peptide arrays and machine learning. ACS Chem Biol 2011; 6:146-57. [PMID: 20945913 DOI: 10.1021/cb100218d] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Accumulating evidence suggests that reversible protein acetylation may be a major regulatory mechanism that rivals phosphorylation. With the recent cataloging of thousands of acetylation sites on hundreds of proteins comes the challenge of identifying the acetyltransferases and deacetylases that regulate acetylation levels. Sirtuins are a conserved family of NAD(+)-dependent protein deacetylases that are implicated in genome maintenance, metabolism, cell survival, and lifespan. SIRT3 is the dominant protein deacetylase in mitochondria, and emerging evidence suggests that SIRT3 may control major pathways by deacetylation of central metabolic enzymes. Here, to identify potential SIRT3 substrates, we have developed an unbiased screening strategy that involves a novel acetyl-lysine analogue (thiotrifluoroacetyl-lysine), SPOT-peptide libraries, machine learning, and kinetic validation. SPOT peptide libraries based on known and potential mitochondrial acetyl-lysine sites were screened for SIRT3 binding and then analyzed using machine learning to establish binding trends. These trends were then applied to the mitochondrial proteome as a whole to predict binding affinity of all lysine sites within human mitochondria. Machine learning prediction of SIRT3 binding correlated with steady-state kinetic k(cat)/K(m) values for 24 acetyl-lysine peptides that possessed a broad range of predicted binding. Thus, SPOT peptide-binding screens and machine learning prediction provides an accurate and efficient method to evaluate sirtuin substrate specificity from a relatively small learning set. These analyses suggest potential SIRT3 substrates involved in several metabolic pathways such as the urea cycle, ATP synthesis, and fatty acid oxidation.
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Affiliation(s)
- Brian C. Smith
- Department of Biomolecular Chemistry, ‡Department of Computer Sciences, and §Department of Biostatistics & Medical Informatics, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Burr Settles
- Department of Biomolecular Chemistry, ‡Department of Computer Sciences, and §Department of Biostatistics & Medical Informatics, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - William C. Hallows
- Department of Biomolecular Chemistry, ‡Department of Computer Sciences, and §Department of Biostatistics & Medical Informatics, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Mark W. Craven
- Department of Biomolecular Chemistry, ‡Department of Computer Sciences, and §Department of Biostatistics & Medical Informatics, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - John M. Denu
- Department of Biomolecular Chemistry, ‡Department of Computer Sciences, and §Department of Biostatistics & Medical Informatics, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
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Fetoni AR, Picciotti PM, Paludetti G, Troiani D. Pathogenesis of presbycusis in animal models: a review. Exp Gerontol 2011; 46:413-25. [PMID: 21211561 DOI: 10.1016/j.exger.2010.12.003] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 11/04/2010] [Accepted: 12/15/2010] [Indexed: 12/14/2022]
Abstract
Presbycusis is the most common cause of hearing loss in aged subjects, reducing individual's communicative skills. Age related hearing loss can be defined as a progressive, bilateral, symmetrical hearing loss due to age related degeneration and it can be considered a multifactorial complex disorder, with both environmental and genetic factors contributing to the aetiology of the disease. The decline in hearing sensitivity caused by ageing is related to the damage at different levels of the auditory system (central and peripheral). Histologically, the aged cochlea shows degeneration of the stria vascularis, the sensorineural epithelium, and neurons of the central auditory pathways. The mechanisms responsible for age-associated hearing loss are still incompletely characterized. This work aims to give a broad overview of the scientific findings related to presbycusis, focusing mainly on experimental studies in animal models.
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Affiliation(s)
- Anna R Fetoni
- Institute of Otolaryngology, School of Medicine, Catholic University of Rome, Largo A. Gemelli, 8 00168 Rome, Italy.
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Manolopoulos KN, Klotz LO, Korsten P, Bornstein SR, Barthel A. Linking Alzheimer's disease to insulin resistance: the FoxO response to oxidative stress. Mol Psychiatry 2010; 15:1046-52. [PMID: 20966918 DOI: 10.1038/mp.2010.17] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Oxidative stress is an important determinant not only in the pathogenesis of Alzheimer's disease (AD), but also in insulin resistance (InsRes) and diabetic complications. Forkhead box class O (FoxO) transcription factors are involved in both insulin action and the cellular response to oxidative stress, thereby providing a potential integrative link between AD and InsRes. For example, the expression of intra- and extracellular antioxidant enzymes, such as manganese-superoxide dismutase and selenoprotein P, is regulated by FoxO proteins, as is the expression of important hepatic enzymes of gluconeogenesis. Here, we review the molecular mechanisms involved in the pathogenesis of AD and InsRes and discuss the function of FoxO proteins in these processes. Both InsRes and oxidative stress may promote the transcriptional activity of FoxO proteins, resulting in hyperglycaemia and a further increased production of reactive oxygen species (ROS). The consecutive activation of c-Jun N-terminal kinases and inhibition of Wingless (Wnt) signalling may result in the formation of β-amyloid plaques and τ protein phosphorylation. Wnt inhibition may also result in a sustained activation of FoxO proteins with induction of apoptosis and neuronal loss, thereby completing a vicious circle from oxidative stress, InsRes and hyperglycaemia back to the formation of ROS and consecutive neurodegeneration. In view of their central function in this model, FoxO proteins may provide a potential molecular target for the treatment of both InsRes and AD.
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Affiliation(s)
- K N Manolopoulos
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital Oxford, Oxford, UK
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36
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Holmuhamedov EL, Czerny C, Lovelace G, Beeson CC, Baker T, Johnson CB, Pediaditakis P, Teplova VV, Tikunov A, MacDonald J, Lemasters JJ. Role of voltage-dependent anion channels of the mitochondrial outer membrane in regulation of cell metabolism. Biophysics (Nagoya-shi) 2010. [DOI: 10.1134/s0006350910050088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Solaini G, Sgarbi G, Baracca A. Oxidative phosphorylation in cancer cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:534-42. [PMID: 20849810 DOI: 10.1016/j.bbabio.2010.09.003] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 08/31/2010] [Accepted: 09/02/2010] [Indexed: 12/26/2022]
Abstract
Evidence suggests that mitochondrial metabolism may play a key role in controlling cancer cells life and proliferation. Recent evidence also indicates how the altered contribution of these organelles to metabolism and the resistance of cancer mitochondria against apoptosis-associated permeabilization are closely related. The hallmarks of cancer growth, increased glycolysis and lactate production in tumours, have raised attention due to recent observations suggesting a wide spectrum of oxidative phosphorylation deficit and decreased availability of ATP associated with malignancies and tumour cell expansion. More specifically, alteration in signal transduction pathways directly affects mitochondrial proteins playing critical roles in controlling the membrane potential as UCP2 and components of both MPTP and oxphos complexes, or in controlling cells life and death as the Bcl-2 proteins family. Moreover, since mitochondrial bioenergetics and dynamics, are also involved in processes of cells life and death, proper regulation of these mitochondrial functions is crucial for tumours to grow. Therefore a better understanding of the key pathophysiological differences between mitochondria in cancer cells and in their non-cancer surrounding tissue is crucial to the finding of tools interfering with these peculiar tumour mitochondrial functions and will disclose novel approaches for the prevention and treatment of malignant diseases. Here, we review the peculiarity of tumour mitochondrial bioenergetics and the mode it is linked to the cell metabolism, providing a short overview of the evidence accumulated so far, but highlighting the more recent advances.
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Affiliation(s)
- Giancarlo Solaini
- Department of Biochemistry "G. Moruzzi", University of Bologna, Via Irnerio 48, 40126 Bologna, Italy.
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Brys K, Castelein N, Matthijssens F, Vanfleteren JR, Braeckman BP. Disruption of insulin signalling preserves bioenergetic competence of mitochondria in ageing Caenorhabditis elegans. BMC Biol 2010; 8:91. [PMID: 20584279 PMCID: PMC2914644 DOI: 10.1186/1741-7007-8-91] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 06/28/2010] [Indexed: 11/30/2022] Open
Abstract
Background The gene daf-2 encodes the single insulin/insulin growth factor-1-like receptor of Caenorhabditis elegans. The reduction-of-function allele e1370 induces several metabolic alterations and doubles lifespan. Results We found that the e1370 mutation alters aerobic energy production substantially. In wild-type worms the abundance of key mitochondrial proteins declines with age, accompanied by a dramatic decrease in energy production, although the mitochondrial mass, inferred from the mitochondrial DNA copy number, remains unaltered. In contrast, the age-dependent decrease of both key mitochondrial proteins and bioenergetic competence is considerably attenuated in daf-2(e1370) adult animals. The increase in daf-2(e1370) mitochondrial competence is associated with a higher membrane potential and increased reactive oxygen species production, but with little damage to mitochondrial protein or DNA. Together these results point to a higher energetic efficiency of daf-2(e1370) animals. Conclusions We conclude that low daf-2 function alters the overall rate of ageing by a yet unidentified mechanism with an indirect protective effect on mitochondrial function.
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Affiliation(s)
- Kristel Brys
- Department of Biology, Ghent University, K L Ledeganckstraat 35, Ghent B-9000, Belgium.
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The toxic effect of thioacetamide on rat liver in vitro. Toxicol In Vitro 2010; 24:2097-103. [PMID: 20600801 DOI: 10.1016/j.tiv.2010.06.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 05/07/2010] [Accepted: 06/08/2010] [Indexed: 01/23/2023]
Abstract
Thioacetamide (TAA) is a hepatotoxin frequently used for experimental purposes which produces centrilobular necrosis after a single dose administration. In spite of the fact that oxidative stress seems to play a very important role in the mechanism of TAA-induced injury, the effect of TAA on hepatocytes in primary culture with respect to the influence on mitochondria has yet to be verified. Hepatocytes were incubated for 24h in a medium containing TAA (0-70 mmol/l). Glutathione content (GSH/GSSG), reactive oxygen species and malondialdehyde formation were assessed as markers of cell redox state. Toxicity was determined by lactate dehydrogenase leakage and WST-1 assay. The functional capacity of hepatocytes was evaluated from albumin and urea production. Mitochondrial metabolism was assessed by measuring mitochondrial membrane potential and oxygen consumption. Our results show that a profound decrease in the GSH level in hepatocytes precedes a sharp rise in endogenous ROS production. ROS production correlates with an increase in lipoperoxidation. Mitochondria are affected by TAA secondarily as a consequence of oxidative stress. Oxidation of the NADH-dependent substrates of respiratory Complex I is significantly more sensitive to the toxic action of TAA than oxidation of the flavoprotein-dependent substrate of Complex II. Mitochondria can also maintain their membrane potential better when they utilize succinate as a respiratory substrate. It appears that GSH should be depleted below a certain critical level in order to cause a marked increase in lipid peroxidation. Mitochondrial injury can then occur and cell death develops.
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Solaini G, Baracca A, Lenaz G, Sgarbi G. Hypoxia and mitochondrial oxidative metabolism. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1797:1171-7. [PMID: 20153717 DOI: 10.1016/j.bbabio.2010.02.011] [Citation(s) in RCA: 395] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 02/02/2010] [Accepted: 02/07/2010] [Indexed: 12/20/2022]
Abstract
It is now clear that mitochondrial defects are associated with a large variety of clinical phenotypes. This is the result of the mitochondria's central role in energy production, reactive oxygen species homeostasis, and cell death. These processes are interdependent and may occur under various stressing conditions, among which low oxygen levels (hypoxia) are certainly prominent. Cells exposed to hypoxia respond acutely with endogenous metabolites and proteins promptly regulating metabolic pathways, but if low oxygen levels are prolonged, cells activate adapting mechanisms, the master switch being the hypoxia-inducible factor 1 (HIF-1). Activation of this factor is strictly bound to the mitochondrial function, which in turn is related with the oxygen level. Therefore in hypoxia, mitochondria act as [O2] sensors, convey signals to HIF-1 directly or indirectly, and contribute to the cell redox potential, ion homeostasis, and energy production. Although over the last two decades cellular responses to low oxygen tension have been studied extensively, mechanisms underlying these functions are still indefinite. Here we review current knowledge of the mitochondrial role in hypoxia, focusing mainly on their role in cellular energy and reactive oxygen species homeostasis in relation with HIF-1 stabilization. In addition, we address the involvement of HIF-1 and the inhibitor protein of F1F0 ATPase in the hypoxia-induced mitochondrial autophagy.
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Affiliation(s)
- Giancarlo Solaini
- Department of Biochemistry G. Moruzzi, University of Bologna, Bologna, Italy.
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Lenaz G, Baracca A, Barbero G, Bergamini C, Dalmonte ME, Del Sole M, Faccioli M, Falasca A, Fato R, Genova ML, Sgarbi G, Solaini G. Mitochondrial respiratory chain super-complex I–III in physiology and pathology. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:633-40. [DOI: 10.1016/j.bbabio.2010.01.025] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 01/20/2010] [Accepted: 01/20/2010] [Indexed: 11/27/2022]
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Xie X, Hu J, Liu X, Qin H, Percival-Smith A, Rao Y, Li SSC. NIP/DuoxA is essential for Drosophila embryonic development and regulates oxidative stress response. Int J Biol Sci 2010; 6:252-67. [PMID: 20567495 PMCID: PMC2878171 DOI: 10.7150/ijbs.6.252] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 09/15/2009] [Indexed: 01/10/2023] Open
Abstract
NIP/DuoxA, originally cloned as a protein capable of binding to the cell fate determinant Numb in Drosophila, was recently identified as a modulator of reactive oxygen species (ROS) production in mammalian systems. Despite biochemical and cellular studies that link NIP/DuoxA to the generation of ROS through the dual oxidase (Duox) enzyme, the in vivo function of NIP/DuoxA has not been characterized to date. Here we report a genetic and functional characterization of nip in Drosophila melanogaster. We show that nip is essential for Drosophila development as nip null mutants die at the 1(st) larval instar. Expression of UAS-nip, but not UAS-Duox, rescued the lethality. To understand the function of nip beyond the early larval stage, we generated GAL4 inducible UAS-RNAi transgenes. da(G32)-GAL4 driven, ubiquitous RNAi-mediated silencing of nip led to profound abnormality in pre-adult development, crinkled wing and markedly reduced lifespan at 29 degrees C. Compared to wild type flies, da-GAL4 induced nip-RNAi transgenic flies exhibited significantly reduced ability to survive under oxidative stress and displayed impaired mitochondrial aconitase function. Our work provides in vivo evidence for a critical role for nip in the development and oxidative stress response in Drosophila.
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Affiliation(s)
- Xiaojun Xie
- Department of Biochemistry and the Siebens-Drake Medical Research Institute, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
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Poeggeler B, Sambamurti K, Siedlak SL, Perry G, Smith MA, Pappolla MA. A novel endogenous indole protects rodent mitochondria and extends rotifer lifespan. PLoS One 2010; 5:e10206. [PMID: 20421998 PMCID: PMC2858081 DOI: 10.1371/journal.pone.0010206] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 03/04/2010] [Indexed: 12/31/2022] Open
Abstract
Aging is a multi-factorial process, however, it is generally accepted that reactive oxygen species (ROS) are significant contributors. Mitochondria are important players in the aging process because they produce most of the cellular ROS. Despite the strength of the free-radical hypothesis, the use of free radical scavengers to delay aging has generated mixed results in vertebrate models, and clinical evidence of efficacy is lacking. This is in part due to the production of pro-oxidant metabolites by many antioxidants while scavenging ROS, which counteract their potentially beneficial effects. As such, a more effective approach is to enhance mitochondrial metabolism by reducing electron leakage with attendant reduction of ROS generation. Here, we report on the actions of a novel endogenous indole derivative, indolepropionamide (IPAM), which is similar in structure to melatonin. Our results suggest that IPAM binds to the rate-limiting component of oxidative phosphorylation in complex I of the respiratory chain and acts as a stabilizer of energy metabolism, thereby reducing ROS production. IPAM reversed the age-dependent decline of mitochondrial energetic capacity and increased rotifer lifespan, and it may, in fact, constitute a novel endogenous anti-aging substance of physiological importance.
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Affiliation(s)
| | - Kumar Sambamurti
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail: (KS); (MAP)
| | - Sandra L. Siedlak
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - George Perry
- UTSA Neurosciences Institute and Department of Biology, College of Sciences, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Mark A. Smith
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Miguel A. Pappolla
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail: (KS); (MAP)
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Lenaz G, Genova ML. Structure and organization of mitochondrial respiratory complexes: a new understanding of an old subject. Antioxid Redox Signal 2010; 12:961-1008. [PMID: 19739941 DOI: 10.1089/ars.2009.2704] [Citation(s) in RCA: 185] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The enzymatic complexes of the mitochondrial respiratory chain have been extensively investigated in their structural and functional properties. A clear distinction is possible today between three complexes in which the difference in redox potential allows proton translocation (complexes I, III, and IV) and those having the mere function to convey electrons to the respiratory chain. We also have a clearer understanding of the structure and function of most respiratory complexes, of their biogenesis and regulation, and of their capacity to generate reactive oxygen species. Past investigations led to the conclusion that the complexes are randomly dispersed and functionally connected by diffusion of smaller redox components, coenzyme Q and cytochrome c. More-recent investigations by native gel electrophoresis and single-particle image processing showed the existence of supramolecular associations. Flux-control analysis demonstrated that complexes I and III in mammals and I, III, and IV in plants kinetically behave as single units, suggesting the existence of substrate channeling. This review discusses conditions affecting the formation of supercomplexes that, besides kinetic advantage, have a role in the stability and assembly of the individual complexes and in preventing excess oxygen radical formation. Disruption of supercomplex organization may lead to functional derangements responsible for pathologic changes.
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Affiliation(s)
- Giorgio Lenaz
- Dipartimento di Biochimica "G. Moruzzi," Alma Mater Studiorum, Università di Bologna, Bologna, Italy.
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Chepelev NL, Bennitz JD, Wright JS, Smith JC, Willmore WG. Oxidative modification of citrate synthase by peroxyl radicals and protection with novel antioxidants. J Enzyme Inhib Med Chem 2010; 24:1319-31. [PMID: 19795928 DOI: 10.3109/14756360902852586] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In mammals, aging is linked to a decline in the activity of citrate synthase (CS; E.C. 2.3.3.1), the first enzyme of the citric acid cycle. We used 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH), a water-soluble generator of peroxyl and alkoxyl radicals, to investigate the susceptibility of CS to oxidative damage. Treatment of isolated mitochondria with AAPH for 8-24 h led to CS inactivation; however, the activity of aconitase, a mitochondrial enzyme routinely used as an oxidative stress marker, was unaffected. In addition to enzyme inactivation, AAPH treatment of purified CS resulted in dityrosine formation, increased protein surface hydrophobicity, and loss of tryptophan fluorescence. Propyl gallate, 1,8-naphthalenediol, 2,3-naphthalenediol, ascorbic acid, glutathione, and oxaloacetate protected CS from AAPH-mediated inactivation, with IC(50) values of 9, 14, 34, 37, 150, and 160 muM, respectively. Surprisingly, the antioxidant epigallocatechin gallate offered no protection against AAPH, but instead caused CS inactivation. Our results suggest that the current practice of using the enzymatic activity of CS as an index of mitochondrial abundance and the use of aconitase activity as an oxidative stress marker may be inappropriate, especially in oxidative stress-related studies, during which alkyl peroxyl and alkoxyl radicals can be generated.
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Dogliotti G, Galliera E, Dozio E, Vianello E, Villa R, Licastro F, Barajon I, Corsi M. Okadaic acid induces apoptosis in Down syndrome fibroblasts. Toxicol In Vitro 2010; 24:815-21. [DOI: 10.1016/j.tiv.2009.12.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Revised: 11/12/2009] [Accepted: 12/09/2009] [Indexed: 10/20/2022]
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Baracca A, Chiaradonna F, Sgarbi G, Solaini G, Alberghina L, Lenaz G. Mitochondrial Complex I decrease is responsible for bioenergetic dysfunction in K-ras transformed cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:314-23. [PMID: 19931505 DOI: 10.1016/j.bbabio.2009.11.006] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 11/06/2009] [Accepted: 11/12/2009] [Indexed: 10/20/2022]
Abstract
Many cancer cells are characterized by high rate of glycolysis and reduced rate of aerobic respiration, whose mechanism is still elusive. Here we investigate the down-regulation of oxidative phosphorylation (OXPHOS) in K-ras transformed mouse fibroblasts as compared to a control counterpart. Transcriptional analysis showed different expression levels of several OXPHOS nuclear genes in the two cell lines. In particular, during the exponential growth phase most genes encoding proteins of Complex I were expressed at lower levels in transformed cells. Consistently, a significant decrease of Complex I content was found in transformed cells. Moreover, analysis of NAD-dependent respiration and ATP synthesis indicated a strong decrease of Complex I activity in the mitochondria from neoplastic cells, that was confirmed by direct assay of the enzyme redox activity. At variance, succinate-dependent respiration and ATP synthesis were not significantly affected. Taken together, our results provide the new insight that the reduction of respiration observed in K-ras transformed cells is specifically due to a Complex I activity decrease.
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Affiliation(s)
- Alessandra Baracca
- Department of Biochemistry "G. Moruzzi", University of Bologna, Bologna, Italy
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Lenaz G, Genova ML. Structural and functional organization of the mitochondrial respiratory chain: a dynamic super-assembly. Int J Biochem Cell Biol 2009; 41:1750-1772. [PMID: 19711505 DOI: 10.1016/j.biocel.2009.04.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The structural organization of the mitochondrial oxidative phosphorylation (OXPHOS) system has received large attention in the past and most investigations led to the conclusion that the respiratory enzymatic complexes are randomly dispersed in the lipid bilayer of the inner membrane and functionally connected by fast diffusion of smaller redox components, Coenzyme Q and cytochrome c. More recent investigations by native gel electrophoresis, however, have shown the existence of supramolecular associations of the respiratory complexes, confirmed by electron microscopy analysis and single particle image processing. Flux control analysis has demonstrated that Complexes I and III in mammalian mitochondria and Complexes I, III, and IV in plant mitochondria kinetically behave as single units with control coefficients approaching unity for each single component, suggesting the existence of substrate channelling within the supercomplexes. The reasons why the presence of substrate channelling for Coenzyme Q and cytochrome c was overlooked in the past are analytically discussed. The review also discusses the forces and the conditions responsible for the formation of the supramolecular units. The function of the supercomplexes appears not to be restricted to kinetic advantages in electron transfer: we discuss evidence on their role in the stability and assembly of the individual complexes and in preventing excess oxygen radical formation. Finally, there is increasing evidence that disruption of the supercomplex organization leads to functional derangements responsible for pathological changes.
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Affiliation(s)
- Giorgio Lenaz
- Dipartimento di Biochimica G. Moruzzi, Università di Bologna, Via Irnerio 48, 40126 Bologna, Italy.
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Modrick ML, Didion SP, Sigmund CD, Faraci FM. Role of oxidative stress and AT1 receptors in cerebral vascular dysfunction with aging. Am J Physiol Heart Circ Physiol 2009; 296:H1914-9. [PMID: 19395552 DOI: 10.1152/ajpheart.00300.2009] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Vascular dysfunction occurs with aging. We hypothesized that oxidative stress and ANG II [acting via ANG II type 1 (AT(1)) receptors] promotes cerebral vascular dysfunction with aging. We studied young (5-6 mo), old (17-19 mo), and very old (23 +/- 1 mo) mice. In basilar arteries in vitro, acetylcholine (an endothelium-dependent agonist) produced dilation in young wild-type mice that was reduced by approximately 60 and 90% (P < 0.05) in old and very old mice, respectively. Similar effects were seen using A23187, a second endothelium-dependent agonist. The vascular response to acetylcholine in very old mice was almost completely restored with tempol (a scavenger of superoxide) and partly restored by PJ34, an inhibitor of poly(ADP-ribose) polymerase (PARP). We used mice deficient in Mn-SOD (Mn-SOD(+/-)) to test whether this form of SOD protected during aging but found that age-induced endothelial dysfunction was not altered by Mn-SOD deficiency. Cerebral vascular responses were similar in young mice lacking AT(1) receptors (AT(1)(-/-)) and wild-type mice. Vascular responses to acetylcholine and A23187 were reduced by approximately 50% in old wild-type mice (P < 0.05) but were normal in old AT(1)-deficient mice. Thus, aging produces marked endothelial dysfunction in the cerebral artery that is mediated by ROS, may involve the activation of PARP, but was not enhanced by Mn-SOD deficiency. Our findings suggest a novel and fundamental role for ANG II and AT(1) receptors in age-induced vascular dysfunction.
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Affiliation(s)
- Mary L Modrick
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, E318-2 GH, Iowa City, IA 52242-1081, USA
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Choi SW, Gerencser AA, Nicholls DG. Bioenergetic analysis of isolated cerebrocortical nerve terminals on a microgram scale: spare respiratory capacity and stochastic mitochondrial failure. J Neurochem 2009; 109:1179-91. [PMID: 19519782 DOI: 10.1111/j.1471-4159.2009.06055.x] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Pre-synaptic nerve terminals (synaptosomes) require ATP for neurotransmitter exocytosis and recovery and for ionic homeostasis, and are consequently abundantly furnished with mitochondria. Pre-synaptic mitochondrial dysfunction is implicated in a variety of neurodegenerative disorders, although there is no precise definition of the term 'dysfunction'. In this study, we test the hypothesis that partial restriction of electron transport through Complexes I and II in synaptosomes to mimic possible defects associated with Parkinson's and Huntington's diseases respectively, sensitizes individual terminals to mitochondrial depolarization under conditions of enhanced proton current utilization, even though these stresses are within the respiratory capacity of the synaptosomes when averaged over the entire population. We combine two novel techniques, firstly using a modification of a plate-based respiration and glycolysis assay that requires only microgram quantities of synaptosomal protein, and secondly developing an improved method for fluorescent imaging and statistical analysis of single synaptosomes. Conditions are defined for optimal substrate supply to the in situ mitochondria within mouse cerebrocortical synaptosomes, and the energetic demands of ion cycling and action-potential firing at the plasma membrane are additionally determined.
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Affiliation(s)
- Sung W Choi
- Buck Institute for Age Research, Novato, California 94945, USA
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