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Perluigi M, Di Domenico F, Butterfield DA. Oxidative damage in neurodegeneration: roles in the pathogenesis and progression of Alzheimer disease. Physiol Rev 2024; 104:103-197. [PMID: 37843394 PMCID: PMC11281823 DOI: 10.1152/physrev.00030.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 03/30/2023] [Accepted: 05/24/2023] [Indexed: 10/17/2023] Open
Abstract
Alzheimer disease (AD) is associated with multiple etiologies and pathological mechanisms, among which oxidative stress (OS) appears as a major determinant. Intriguingly, OS arises in various pathways regulating brain functions, and it seems to link different hypotheses and mechanisms of AD neuropathology with high fidelity. The brain is particularly vulnerable to oxidative damage, mainly because of its unique lipid composition, resulting in an amplified cascade of redox reactions that target several cellular components/functions ultimately leading to neurodegeneration. The present review highlights the "OS hypothesis of AD," including amyloid beta-peptide-associated mechanisms, the role of lipid and protein oxidation unraveled by redox proteomics, and the antioxidant strategies that have been investigated to modulate the progression of AD. Collected studies from our groups and others have contributed to unraveling the close relationships between perturbation of redox homeostasis in the brain and AD neuropathology by elucidating redox-regulated events potentially involved in both the pathogenesis and progression of AD. However, the complexity of AD pathological mechanisms requires an in-depth understanding of several major intracellular pathways affecting redox homeostasis and relevant for brain functions. This understanding is crucial to developing pharmacological strategies targeting OS-mediated toxicity that may potentially contribute to slow AD progression as well as improve the quality of life of persons with this severe dementing disorder.
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Affiliation(s)
- Marzia Perluigi
- Department of Biochemical Sciences "A. Rossi Fanelli," Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
| | - Fabio Di Domenico
- Department of Biochemical Sciences "A. Rossi Fanelli," Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
| | - D Allan Butterfield
- Department of Chemistry and Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, United States
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Dubey Tiwari K, Sharma G, Prakash M, Parihar M, Dawane V. Effects of high glutamate concentrations on mitochondria of human neuroblastoma SH-SY5Y cells. ANNALES PHARMACEUTIQUES FRANÇAISES 2022; 81:457-465. [PMID: 36252868 DOI: 10.1016/j.pharma.2022.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 09/17/2022] [Accepted: 10/10/2022] [Indexed: 11/05/2022]
Abstract
BACKGROUND The excess amount of glutamate in neurons is associated with the excitotoxicity and neurodegenerative diseases. Glutamate induces neurotoxicity primarily by immense influx of Ca2+ arising from overstimulation of the NMDA subtype of glutamate receptors. The neuronal death induced by the overstimulation of glutamate receptors depends critically on a sustained increase in mitochondrial Ca2+ influx and impairment in mitochondrial functions. The mitochondrial impairment is an important contributor to the glutamate-induced neuronal toxicity and thus provides an important target for the intervention. The present study investigates the effects of high glutamate concentrations on mitochondrial functions. RESULTS Here, we have shown that the higher concentration of glutamate treatment caused a significant elevation in the N-methyl-D-aspartate (NMDA) receptors expression and elevated the intra-mitochondrial calcium accumulation in SHSY5Y neuronal cells. As a result of an accumulation of intra-mitochondrial calcium, there is a concentration-dependent elevation in ROS in the mitochondria. Tyrosine nitration of several mitochondrial proteins was increased while the mitochondrial membrane potential was dissipated. Furthermore, glutamate treatments also resulted in mitochondrial membrane permeability transition. CONCLUSIONS These findings suggest that treatment of high glutamate concentration causes impairment of mitochondrial functions by an increase in intra-mitochondrial calcium, ROS production, dissipation of mitochondrial membrane potential and mitochondrial permeability transition pore opening in human neuroblastoma SHSY5Y cells.
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Xin N, Durieux J, Yang C, Wolff S, Kim HE, Dillin A. The UPRmt preserves mitochondrial import to extend lifespan. J Cell Biol 2022; 221:e202201071. [PMID: 35608535 PMCID: PMC9134095 DOI: 10.1083/jcb.202201071] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/14/2022] [Accepted: 04/26/2022] [Indexed: 01/07/2023] Open
Abstract
The mitochondrial unfolded protein response (UPRmt) is dedicated to promoting mitochondrial proteostasis and is linked to extreme longevity. The key regulator of this process is the transcription factor ATFS-1, which, upon UPRmt activation, is excluded from the mitochondria and enters the nucleus to regulate UPRmt genes. However, the repair proteins synthesized as a direct result of UPRmt activation must be transported into damaged mitochondria that had previously excluded ATFS-1 owing to reduced import efficiency. To address this conundrum, we analyzed the role of the import machinery when the UPRmt was induced. Using in vitro and in vivo analysis of mitochondrial proteins, we surprisingly find that mitochondrial import increases when the UPRmt is activated in an ATFS-1-dependent manner, despite reduced mitochondrial membrane potential. The import machinery is upregulated, and an intact import machinery is essential for UPRmt-mediated lifespan extension. ATFS-1 has a weak mitochondrial targeting sequence (MTS), allowing for dynamic subcellular localization during the initial stages of UPRmt activation.
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Affiliation(s)
- Nan Xin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
- Department of Integrated Biology and Pharmacology, University of Texas, Health Science Center, Houston, TX
| | - Jenni Durieux
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Chunxia Yang
- Department of Integrated Biology and Pharmacology, University of Texas, Health Science Center, Houston, TX
| | - Suzanne Wolff
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Hyun-Eui Kim
- Department of Integrated Biology and Pharmacology, University of Texas, Health Science Center, Houston, TX
| | - Andrew Dillin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
- Howard Hughes Medical Institute, Chevy Chase, MD
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4
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Bentea E, De Pauw L, Verbruggen L, Winfrey LC, Deneyer L, Moore C, Albertini G, Sato H, Van Eeckhaut A, Meshul CK, Massie A. Aged xCT-Deficient Mice Are Less Susceptible for Lactacystin-, but Not 1-Methyl-4-Phenyl-1,2,3,6- Tetrahydropyridine-, Induced Degeneration of the Nigrostriatal Pathway. Front Cell Neurosci 2022; 15:796635. [PMID: 34975413 PMCID: PMC8718610 DOI: 10.3389/fncel.2021.796635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 11/24/2021] [Indexed: 12/23/2022] Open
Abstract
The astrocytic cystine/glutamate antiporter system x c - (with xCT as the specific subunit) imports cystine in exchange for glutamate and has been shown to interact with multiple pathways in the brain that are dysregulated in age-related neurological disorders, including glutamate homeostasis, redox balance, and neuroinflammation. In the current study, we investigated the effect of genetic xCT deletion on lactacystin (LAC)- and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced degeneration of the nigrostriatal pathway, as models for Parkinson's disease (PD). Dopaminergic neurons of adult xCT knock-out mice (xCT-/-) demonstrated an equal susceptibility to intranigral injection of the proteasome inhibitor LAC, as their wild-type (xCT+/+) littermates. Contrary to adult mice, aged xCT-/- mice showed a significant decrease in LAC-induced degeneration of nigral dopaminergic neurons, depletion of striatal dopamine (DA) and neuroinflammatory reaction, compared to age-matched xCT+/+ littermates. Given this age-related protection, we further investigated the sensitivity of aged xCT-/- mice to chronic and progressive MPTP treatment. However, in accordance with our previous observations in adult mice (Bentea et al., 2015a), xCT deletion did not confer protection against MPTP-induced nigrostriatal degeneration in aged mice. We observed an increased loss of nigral dopaminergic neurons, but equal striatal DA denervation, in MPTP-treated aged xCT-/- mice when compared to age-matched xCT+/+ littermates. To conclude, we reveal age-related protection against proteasome inhibition-induced nigrostriatal degeneration in xCT-/- mice, while xCT deletion failed to protect nigral dopaminergic neurons of aged mice against MPTP-induced toxicity. Our findings thereby provide new insights into the role of system x c - in mechanisms of dopaminergic cell loss and its interaction with aging.
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Affiliation(s)
- Eduard Bentea
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Laura De Pauw
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Lise Verbruggen
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Lila C Winfrey
- Neurocytology Laboratory, Veterans Affairs Medical Center, Research Services, Portland, OR, United States
| | - Lauren Deneyer
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Cynthia Moore
- Neurocytology Laboratory, Veterans Affairs Medical Center, Research Services, Portland, OR, United States
| | - Giulia Albertini
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Hideyo Sato
- Department of Medical Technology, Niigata University, Niigata, Japan
| | - Ann Van Eeckhaut
- Research Group Experimental Pharmacology, Department of Pharmaceutical Chemistry, Drug Analysis and Drug Information, Vrije Universiteit Brussel, Brussels, Belgium
| | - Charles K Meshul
- Neurocytology Laboratory, Veterans Affairs Medical Center, Research Services, Portland, OR, United States.,Department of Behavioral Neuroscience and Pathology, Oregon Health and Science University, Portland, OR, United States
| | - Ann Massie
- Laboratory of Neuro-Aging and Viro-Immunotherapy, Vrije Universiteit Brussel, Brussels, Belgium
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5
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Liang J, Wang C, Zhang H, Huang J, Xie J, Chen N. Exercise-Induced Benefits for Alzheimer's Disease by Stimulating Mitophagy and Improving Mitochondrial Function. Front Aging Neurosci 2021; 13:755665. [PMID: 34658846 PMCID: PMC8519401 DOI: 10.3389/fnagi.2021.755665] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/06/2021] [Indexed: 12/11/2022] Open
Abstract
Neurons are highly specialized post-mitotic cells that are inherently dependent on mitochondria due to their higher bioenergetic demand. Mitochondrial dysfunction is closely associated with a variety of aging-related neurological disorders, such as Alzheimer’s disease (AD), and the accumulation of dysfunctional and superfluous mitochondria has been reported as an early stage that significantly facilitates the progression of AD. Mitochondrial damage causes bioenergetic deficiency, intracellular calcium imbalance and oxidative stress, thereby aggravating β-amyloid (Aβ) accumulation and Tau hyperphosphorylation, and further leading to cognitive decline and memory loss. Although there is an intricate parallel relationship between mitochondrial dysfunction and AD, their triggering factors, such as Aβ aggregation and hyperphosphorylated Tau protein and action time, are still unclear. Moreover, many studies have confirmed abnormal mitochondrial biosynthesis, dynamics and functions will present once the mitochondrial quality control is impaired, thus leading to aggravated AD pathological changes. Accumulating evidence shows beneficial effects of appropriate exercise on improved mitophagy and mitochondrial function to promote mitochondrial plasticity, reduce oxidative stress, enhance cognitive capacity and reduce the risks of cognitive impairment and dementia in later life. Therefore, stimulating mitophagy and optimizing mitochondrial function through exercise may forestall the neurodegenerative process of AD.
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Affiliation(s)
- Jiling Liang
- Tianjiu Research and Development Center for Exercise Nutrition and Foods, Hubei Key Laboratory of Exercise Training and Monitoring, College of Health Science, Wuhan Sports University, Wuhan, China
| | - Cenyi Wang
- School of Physical Education and Sports Science, Soochow University, Suzhou, China
| | - Hu Zhang
- Tianjiu Research and Development Center for Exercise Nutrition and Foods, Hubei Key Laboratory of Exercise Training and Monitoring, College of Health Science, Wuhan Sports University, Wuhan, China
| | - Jielun Huang
- Tianjiu Research and Development Center for Exercise Nutrition and Foods, Hubei Key Laboratory of Exercise Training and Monitoring, College of Health Science, Wuhan Sports University, Wuhan, China
| | - Juying Xie
- Affiliated Hospital of Xiangnan University, Chenzhou, China
| | - Ning Chen
- Tianjiu Research and Development Center for Exercise Nutrition and Foods, Hubei Key Laboratory of Exercise Training and Monitoring, College of Health Science, Wuhan Sports University, Wuhan, China
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Pharaoh G, Owen D, Yeganeh A, Premkumar P, Farley J, Bhaskaran S, Ashpole N, Kinter M, Van Remmen H, Logan S. Disparate Central and Peripheral Effects of Circulating IGF-1 Deficiency on Tissue Mitochondrial Function. Mol Neurobiol 2019; 57:1317-1331. [PMID: 31732912 PMCID: PMC7060968 DOI: 10.1007/s12035-019-01821-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 10/23/2019] [Indexed: 12/15/2022]
Abstract
Age-related decline in circulating levels of insulin-like growth factor (IGF)-1 is associated with reduced cognitive function, neuronal aging, and neurodegeneration. Decreased mitochondrial function along with increased reactive oxygen species (ROS) and accumulation of damaged macromolecules are hallmarks of cellular aging. Based on numerous studies indicating pleiotropic effects of IGF-1 during aging, we compared the central and peripheral effects of circulating IGF-1 deficiency on tissue mitochondrial function using an inducible liver IGF-1 knockout (LID). Circulating levels of IGF-1 (~ 75%) were depleted in adult male Igf1f/f mice via AAV-mediated knockdown of hepatic IGF-1 at 5 months of age. Cognitive function was evaluated at 18 months using the radial arm water maze and glucose and insulin tolerance assessed. Mitochondrial function was analyzed in hippocampus, muscle, and visceral fat tissues using high-resolution respirometry O2K as well as redox status and oxidative stress in the cortex. Peripherally, IGF-1 deficiency did not significantly impact muscle mass or mitochondrial function. Aged LID mice were insulin resistant and exhibited ~ 60% less adipose tissue but increased fat mitochondrial respiration (20%). The effects on fat metabolism were attributed to increases in growth hormone. Centrally, IGF-1 deficiency impaired hippocampal-dependent spatial acquisition as well as reversal learning in male mice. Hippocampal mitochondrial OXPHOS coupling efficiency and cortex ATP levels (~ 50%) were decreased and hippocampal oxidative stress (protein carbonylation and F2-isoprostanes) was increased. These data suggest that IGF-1 is critical for regulating mitochondrial function, redox status, and spatial learning in the central nervous system but has limited impact on peripheral (liver and muscle) metabolism with age. Therefore, IGF-1 deficiency with age may increase sensitivity to damage in the brain and propensity for cognitive deficits. Targeting mitochondrial function in the brain may be an avenue for therapy of age-related impairment of cognitive function. Regulation of mitochondrial function and redox status by IGF-1 is essential to maintain brain function and coordinate hippocampal-dependent spatial learning. While a decline in IGF-1 in the periphery may be beneficial to avert cancer progression, diminished central IGF-1 signaling may mediate, in part, age-related cognitive dysfunction and cognitive pathologies potentially by decreasing mitochondrial function.
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Affiliation(s)
- Gavin Pharaoh
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Daniel Owen
- Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Alexander Yeganeh
- Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Pavithra Premkumar
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Julie Farley
- Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Shylesh Bhaskaran
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Nicole Ashpole
- Department of Biomolecular Sciences, University of Mississippi, Oxford, MS, USA
| | - Michael Kinter
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Holly Van Remmen
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.,Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Sreemathi Logan
- Oklahoma Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Department of Rehabilitation Sciences, College of Allied Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Mattedi F, Vagnoni A. Temporal Control of Axonal Transport: The Extreme Case of Organismal Ageing. Front Cell Neurosci 2019; 13:393. [PMID: 31555095 PMCID: PMC6716446 DOI: 10.3389/fncel.2019.00393] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/09/2019] [Indexed: 01/05/2023] Open
Abstract
A fundamental question in cell biology is how cellular components are delivered to their destination with spatial and temporal precision within the crowded cytoplasmic environment. The long processes of neurons represent a significant spatial challenge and make these cells particularly dependent on mechanisms for long-range cytoskeletal transport of proteins, RNA and organelles. Although many studies have substantiated a role for defective transport of axonal cargoes in the pathogenesis of neurodevelopmental and neurodegenerative diseases, remarkably little is known about how transport is regulated throughout ageing. The scale of the challenge posed by ageing is considerable because, in this case, the temporal regulation of transport is ultimately dictated by the length of organismal lifespan, which can extend to days, years or decades. Recent methodological advances to study live axonal transport during ageing in situ have provided new tools to scratch beneath the surface of this complex problem and revealed that age-dependent decline in the transport of mitochondria is a common feature across different neuronal populations of several model organisms. In certain instances, the molecular pathways that affect transport in ageing animals have begun to emerge. However, the functional implications of these observations are still not fully understood. Whether transport decline is a significant determinant of neuronal ageing or a mere consequence of decreased cellular fitness remains an open question. In this review, we discuss the latest developments in axonal trafficking in the ageing nervous system, along with the early studies that inaugurated this new area of research. We explore the possibility that the interplay between mitochondrial function and motility represents a crucial driver of ageing in neurons and put forward the hypothesis that declining axonal transport may be legitimately considered a hallmark of neuronal ageing.
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Affiliation(s)
| | - Alessio Vagnoni
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, IoPPN, King’s College London, London, United Kingdom
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Myers MJ, Shepherd DL, Durr AJ, Stanton DS, Mohamed JS, Hollander JM, Alway SE. The role of SIRT1 in skeletal muscle function and repair of older mice. J Cachexia Sarcopenia Muscle 2019; 10:929-949. [PMID: 31197980 PMCID: PMC6711423 DOI: 10.1002/jcsm.12437] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 03/21/2019] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Sirtuin 1 (SIRT1) is a NAD+ sensitive deacetylase that has been linked to longevity and has been suggested to confer beneficial effects that counter aging-associated deterioration. Muscle repair is dependent upon satellite cell function, which is reported to be reduced with aging; however, it is not known if this is linked to an aging-suppression of SIRT1. This study tested the hypothesis that Sirtuin 1 (SIRT1) overexpression would increase the extent of muscle repair and muscle function in older mice. METHODS We examined satellite cell dependent repair in tibialis anterior, gastrocnemius, and soleus muscles of 13 young wild-type mice (20-30 weeks) and 49 older (80+ weeks) mice that were controls (n = 13), overexpressed SIRT1 in skeletal muscle (n = 14), and had a skeletal muscle SIRT1 knockout (n = 12) or a satellite cell SIRT1 knockout (n = 10). Acute muscle injury was induced by injection of cardiotoxin (CTX), and phosphate-buffered saline was used as a vector control. Plantarflexor muscle force and fatigue were evaluated before or 21 days after CTX injection. Satellite cell proliferation and mitochondrial function were also evaluated in undamaged muscles. RESULTS Maximal muscle force was significantly lower in control muscles of older satellite cell knockout SIRT1 mice compared to young adult wild-type (YWT) mice (P < 0.001). Mean contraction force at 40 Hz stimulation was significantly greater after recovery from CTX injury in older mice that overexpressed muscle SIRT1 than age-matched SIRT1 knockout mice (P < 0.05). SIRT1 muscle knockout models (P < 0.05) had greater levels of p53 (P < 0.05 MKO, P < 0.001 OE) in CTX-damaged tissues as compared to YWT CTX mice. SIRT1 overexpression with co-expression of p53 was associated with increased fatigue resistance and increased force potentiation during repeated contractions as compared to wild-type or SIRT1 knockout models (P < 0.001). Muscle structure and mitochondrial function were not different between the groups, but proliferation of satellite cells was significantly greater in older mice with SIRT1 muscle knockout (P < 0.05), but not older SIRT1 satellite cell knockout models, in vitro, although this effect was attenuated in vivo after 21 days of recovery. CONCLUSIONS The data suggest skeletal muscle structure, function, and recovery after CTX-induced injury are not significantly influenced by gain or loss of SIRT1 abundance alone in skeletal muscle; however, muscle function is impaired by ablation of SIRT1 in satellite cells. SIRT1 appears to interact with p53 to improve muscle fatigue resistance after repair from muscle injury.
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Affiliation(s)
- Matthew J. Myers
- Laboratory of Muscle Biology and SarcopeniaWest Virginia University School of MedicineMorgantownUSA
| | - Danielle L. Shepherd
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory SciencesWest Virginia University School of MedicineMorgantownUSA
| | - Andrya J. Durr
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory SciencesWest Virginia University School of MedicineMorgantownUSA
| | - David S. Stanton
- Laboratory of Muscle Biology and SarcopeniaWest Virginia University School of MedicineMorgantownUSA
| | - Junaith S. Mohamed
- Laboratory of Muscle Biology and SarcopeniaWest Virginia University School of MedicineMorgantownUSA
- Laboratory of Nerve and Muscle, Department of Clinical Laboratory Sciences, College of Health ProfessionsUniversity of Tennessee Health Science CenterMemphisUSA
| | - John M. Hollander
- Division of Exercise Physiology and Center for Cardiovascular and Respiratory SciencesWest Virginia University School of MedicineMorgantownUSA
| | - Stephen E. Alway
- Laboratory of Muscle Biology and SarcopeniaWest Virginia University School of MedicineMorgantownUSA
- Laboratory of Muscle Biology and Sarcopenia, Department of Physical Therapy, College of Health ProfessionsUniversity of Tennessee Health Science CenterMemphisUSA
- Department of Physiology, College of MedicineUniversity of Tennessee Health Science CenterMemphisUSA
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Sharma G, Parihar A, Parihar P, Parihar MS. Downregulation of sirtuin 3 by palmitic acid increases the oxidative stress, impairment of mitochondrial function, and apoptosis in liver cells. J Biochem Mol Toxicol 2019; 33:e22337. [DOI: 10.1002/jbt.22337] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/10/2019] [Accepted: 03/25/2019] [Indexed: 01/22/2023]
Affiliation(s)
- Garima Sharma
- School of Studies in Zoology & BiotechnologyVikram University Ujjain Madhya Pradesh India
| | - Arti Parihar
- Department of ScienceBellingham Technical College Bellingham Washington USA
| | - Priyanka Parihar
- School of Studies in Zoology & BiotechnologyVikram University Ujjain Madhya Pradesh India
| | - Mordhwaj Singh Parihar
- School of Studies in Zoology & BiotechnologyVikram University Ujjain Madhya Pradesh India
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Logan S, Pharaoh GA, Marlin MC, Masser DR, Matsuzaki S, Wronowski B, Yeganeh A, Parks EE, Premkumar P, Farley JA, Owen DB, Humphries KM, Kinter M, Freeman WM, Szweda LI, Van Remmen H, Sonntag WE. Insulin-like growth factor receptor signaling regulates working memory, mitochondrial metabolism, and amyloid-β uptake in astrocytes. Mol Metab 2018; 9:141-155. [PMID: 29398615 PMCID: PMC5870102 DOI: 10.1016/j.molmet.2018.01.013] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/11/2018] [Accepted: 01/16/2018] [Indexed: 01/01/2023] Open
Abstract
Objective A decline in mitochondrial function and biogenesis as well as increased reactive oxygen species (ROS) are important determinants of aging. With advancing age, there is a concomitant reduction in circulating levels of insulin-like growth factor-1 (IGF-1) that is closely associated with neuronal aging and neurodegeneration. In this study, we investigated the effect of the decline in IGF-1 signaling with age on astrocyte mitochondrial metabolism and astrocyte function and its association with learning and memory. Methods Learning and memory was assessed using the radial arm water maze in young and old mice as well as tamoxifen-inducible astrocyte-specific knockout of IGFR (GFAP-CreTAM/igfrf/f). The impact of IGF-1 signaling on mitochondrial function was evaluated using primary astrocyte cultures from igfrf/f mice using AAV-Cre mediated knockdown using Oroboros respirometry and Seahorse assays. Results Our results indicate that a reduction in IGF-1 receptor (IGFR) expression with age is associated with decline in hippocampal-dependent learning and increased gliosis. Astrocyte-specific knockout of IGFR also induced impairments in working memory. Using primary astrocyte cultures, we show that reducing IGF-1 signaling via a 30–50% reduction IGFR expression, comparable to the physiological changes in IGF-1 that occur with age, significantly impaired ATP synthesis. IGFR deficient astrocytes also displayed altered mitochondrial structure and function and increased mitochondrial ROS production associated with the induction of an antioxidant response. However, IGFR deficient astrocytes were more sensitive to H2O2-induced cytotoxicity. Moreover, IGFR deficient astrocytes also showed significantly impaired glucose and Aβ uptake, both critical functions of astrocytes in the brain. Conclusions Regulation of astrocytic mitochondrial function and redox status by IGF-1 is essential to maintain astrocytic function and coordinate hippocampal-dependent spatial learning. Age-related astrocytic dysfunction caused by diminished IGF-1 signaling may contribute to the pathogenesis of Alzheimer's disease and other age-associated cognitive pathologies. Altered mitochondrial structure and function with IGFR deficiency in astrocytes is proposed. Increased reactive oxygen species production and susceptibility to peroxide induced cytotoxicity. Decreased Aβ uptake and impairment in spatial working memory.
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Affiliation(s)
- Sreemathi Logan
- Reynold's Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, USA.
| | - Gavin A Pharaoh
- Department of Physiology, University of Oklahoma Health Sciences Center, USA; Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, USA
| | - M Caleb Marlin
- Graduate College, University of Oklahoma Health Sciences Center, USA
| | - Dustin R Masser
- Reynold's Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, USA; Department of Physiology, University of Oklahoma Health Sciences Center, USA
| | - Satoshi Matsuzaki
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, USA; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, USA
| | - Benjamin Wronowski
- Reynold's Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, USA; Department of Physiology, University of Oklahoma Health Sciences Center, USA
| | - Alexander Yeganeh
- Reynold's Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, USA; Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, USA
| | - Eileen E Parks
- Reynold's Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, USA; Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, USA
| | - Pavithra Premkumar
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, USA
| | - Julie A Farley
- Reynold's Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, USA
| | - Daniel B Owen
- Reynold's Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, USA
| | - Kenneth M Humphries
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, USA; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, USA
| | - Michael Kinter
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, USA
| | - Willard M Freeman
- Reynold's Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, USA; Department of Physiology, University of Oklahoma Health Sciences Center, USA; Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, USA
| | - Luke I Szweda
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, USA; Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, USA
| | - Holly Van Remmen
- Department of Physiology, University of Oklahoma Health Sciences Center, USA; Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, USA; Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, USA
| | - William E Sonntag
- Reynold's Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, USA; Department of Physiology, University of Oklahoma Health Sciences Center, USA; Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, USA
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11
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Him A, Altuntaş S, Öztürk G, Erdoğan E, Cengiz N. Isolation and culture of adult mouse vestibular nucleus neurons. Turk J Med Sci 2017; 47:1903-1911. [PMID: 29306256 DOI: 10.3906/sag-1706-158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Background/aim: Isolated cell cultures are widely used to study neuronal properties due to their advantages. Although embryonic animals are preferred for culturing, their morphological or electrophysiological properties may not reflect adult neurons, which may be important in neurodegenerative diseases. This paper aims to develop a method for preparing isolated cell cultures of medial vestibular nucleus (MVN) from adult mice and describe its morphological and electrophysiological properties.Materials and methods: Vestibular nucleus neurons were mechanically and enzymatically isolated and cultured using a defined medium with known growth factors. Cell survival was measured with propidium iodide, and electrophysiological properties were investigated with current-clamp recording.Results: Vestibular neurons grew neurites in cultures, gaining adult-like morphological properties, and stayed viable for 3 days in culture. Adding bovine calf serum, nerve growth factor, or insulin-like growth factor into the culture medium enhanced neuronal viability. Current-clamp recording of the cultured neurons revealed tonic and phasic-type neurons with similar input resistance, resting membrane potential, action potential amplitude, and duration. Conclusion: Vestibular neurons from adult mice can be cultured, and regenerate axons in a medium containing appropriate growth factors. Culturing adult vestibular neurons provides a new method to study age-related pathologies of the vestibular system.
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12
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Neuroinflammation, immune system and Alzheimer disease: searching for the missing link. Aging Clin Exp Res 2017; 29:821-831. [PMID: 27718173 DOI: 10.1007/s40520-016-0637-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 09/29/2016] [Indexed: 12/19/2022]
Abstract
Due to an increasingly aging population, Alzheimer disease (AD) represents a crucial issue for the healthcare system because of its widespread prevalence and the burden of its care needs. Several hypotheses on AD pathogenesis have been proposed and current therapeutical strategies have shown limited effectiveness. In the last decade, more evidence has supported a role for neuroinflammation and immune system dysregulation in AD. It remains unclear whether astrocytes, microglia and immune cells influence disease onset, progression or both. Amyloid-β peptides that aggregate extracellularly in the typical neuritic plaques generate a constant inflammatory environment. This causes a prolonged activation of microglial and astroglial cells that potentiate neuronal damage and provoke the alteration of the blood brain barrier (BBB), damaging the permeability of blood vessels. Recent data support the role of the BBB as a link between neuroinflammation, the immune system and AD. Hence, a thorough investigation of the neuroinflammatory and immune system pathways that impact neurodegeneration and novel exciting findings such as microglia-derived microvesicles, inflammasomes and signalosomes will ultimately enhance our understanding of the pathological process. Eventually, we should proceed with caution in defining a causal or consequential role of neuroinflammation in AD, but rather focus on identifying its exact pathological contribution.
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13
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Mitochondrial Function and Mitophagy in the Elderly: Effects of Exercise. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:2012798. [PMID: 28900532 PMCID: PMC5576425 DOI: 10.1155/2017/2012798] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 06/04/2017] [Accepted: 07/06/2017] [Indexed: 12/22/2022]
Abstract
Aging is a natural, multifactorial and multiorganic phenomenon wherein there are gradual physiological and pathological changes over time. Aging has been associated with a decrease of autophagy capacity and mitochondrial functions, such as biogenesis, dynamics, and mitophagy. These processes are essential for the maintenance of mitochondrial structural integrity and, therefore, for cell life, since mitochondrial dysfunction leads to an impairment of energy metabolism and increased production of reactive oxygen species, which consequently trigger mechanisms of cellular senescence and apoptotic cell death. Moreover, reduced mitochondrial function can contribute to age-associated disease phenotypes in model organisms and humans. Literature data show beneficial effects of exercise on the impairment of mitochondrial biogenesis and dynamics and on the decrease in the mitophagic capacity associated to aging. Thus, exercise could have effects on the major cell signaling pathways that are involved in the mitochondria quality and quantity control in the elderly. Although it is known that several exercise protocols are able to modify the activity and turnover of mitochondria, further studies are necessary in order to better identify the mechanisms of interaction between mitochondrial functions, aging, and physical activity, as well as to analyze possible factors influencing these processes.
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14
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Liao Y, Dong Y, Cheng J. The Function of the Mitochondrial Calcium Uniporter in Neurodegenerative Disorders. Int J Mol Sci 2017; 18:ijms18020248. [PMID: 28208618 PMCID: PMC5343785 DOI: 10.3390/ijms18020248] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/17/2017] [Accepted: 01/18/2017] [Indexed: 11/16/2022] Open
Abstract
The mitochondrial calcium uniporter (MCU)-a calcium uniporter on the inner membrane of mitochondria-controls the mitochondrial calcium uptake in normal and abnormal situations. Mitochondrial calcium is essential for the production of adenosine triphosphate (ATP); however, excessive calcium will induce mitochondrial dysfunction. Calcium homeostasis disruption and mitochondrial dysfunction is observed in many neurodegenerative disorders. However, the role and regulatory mechanism of the MCU in the development of these diseases are obscure. In this review, we summarize the role of the MCU in controlling oxidative stress-elevated mitochondrial calcium and its function in neurodegenerative disorders. Inhibition of the MCU signaling pathway might be a new target for the treatment of neurodegenerative disorders.
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Affiliation(s)
- Yajin Liao
- The Brain Science Center, Beijing Institute of Basic Medical Sciences, No. 27 Taiping Road, Haidian District, Beijing 100039, China.
- The State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Yuan Dong
- Department of Biochemistry, Qingdao University Medical College, Qingdao 266071, China.
| | - Jinbo Cheng
- The State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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15
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Stebbings KA, Choi HW, Ravindra A, Llano DA. The impact of aging, hearing loss, and body weight on mouse hippocampal redox state, measured in brain slices using fluorescence imaging. Neurobiol Aging 2016; 42:101-9. [PMID: 27143426 DOI: 10.1016/j.neurobiolaging.2016.03.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/18/2016] [Accepted: 03/05/2016] [Indexed: 01/21/2023]
Abstract
The relationships between oxidative stress in the hippocampus and other aging-related changes such as hearing loss, cortical thinning, or changes in body weight are not yet known. We measured the redox ratio in a number of neural structures in brain slices taken from young and aged mice. Hearing thresholds, body weight, and cortical thickness were also measured. We found striking aging-related increases in the redox ratio that were isolated to the stratum pyramidale, while such changes were not observed in thalamus or cortex. These changes were driven primarily by changes in flavin adenine dinucleotide, not nicotinamide adenine dinucleotide hydride. Multiple regression analysis suggested that neither hearing threshold nor cortical thickness independently contributed to this change in hippocampal redox ratio. However, body weight did independently contribute to predicted changes in hippocampal redox ratio. These data suggest that aging-related changes in hippocampal redox ratio are not a general reflection of overall brain oxidative state but are highly localized, while still being related to at least one marker of late aging, weight loss at the end of life.
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Affiliation(s)
- Kevin A Stebbings
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Hyun W Choi
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Aditya Ravindra
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Daniel Adolfo Llano
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA; Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
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16
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Kubik LL, Philbert MA. The role of astrocyte mitochondria in differential regional susceptibility to environmental neurotoxicants: tools for understanding neurodegeneration. Toxicol Sci 2015; 144:7-16. [PMID: 25740792 DOI: 10.1093/toxsci/kfu254] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In recent decades, there has been a significant expansion in our understanding of the role of astrocytes in neuroprotection, including spatial buffering of extracellular ions, secretion of metabolic coenzymes, and synaptic regulation. Astrocytic neuroprotective functions require energy, and therefore require a network of functional mitochondria. Disturbances to astrocytic mitochondrial homeostasis and their ability to produce ATP can negatively impact neural function. Perturbations in astrocyte mitochondrial function may accrue as the result of physiological aging processes or as a consequence of neurotoxicant exposure. Hydrophobic environmental neurotoxicants, such as 1,3-dinitrobenzene and α-chlorohydrin, cause regionally specific spongiform lesions mimicking energy deprivation syndromes. Astrocyte involvement includes mitochondrial damage that either precedes or is accompanied by neuronal damage. Similarly, environmental neurotoxicants that are implicated in the etiology of age-related neurodegenerative conditions cause regionally specific damage in the brain. Based on the regioselective nature of age-related neurodegenerative lesions, chemically induced models of regioselective lesions targeting astrocyte mitochondria can provide insight into age-related susceptibilities in astrocyte mitochondria. Most of the available research to date focuses on neuronal damage in cases of age-related neurodegeneration; however, there is a body of evidence that supports a central mechanistic role for astrocyte mitochondria in the expression of neural injury. Regional susceptibility to neuronal damage induced by aging by exposure to neurotoxicants may be a reflection of highly variable regional energy requirements. This review identifies region-specific vulnerabilities in astrocyte mitochondria in examples of exposure to neurotoxicants and in age-related neurodegeneration.
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Affiliation(s)
- Laura L Kubik
- Toxicology Program, Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109
| | - Martin A Philbert
- Toxicology Program, Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109
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17
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von Bernhardi R, Eugenín-von Bernhardi L, Eugenín J. Microglial cell dysregulation in brain aging and neurodegeneration. Front Aging Neurosci 2015; 7:124. [PMID: 26257642 PMCID: PMC4507468 DOI: 10.3389/fnagi.2015.00124] [Citation(s) in RCA: 357] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2015] [Accepted: 06/22/2015] [Indexed: 12/29/2022] Open
Abstract
Aging is the main risk factor for neurodegenerative diseases. In aging, microglia undergoes phenotypic changes compatible with their activation. Glial activation can lead to neuroinflammation, which is increasingly accepted as part of the pathogenesis of neurodegenerative diseases, including Alzheimer’s disease (AD). We hypothesize that in aging, aberrant microglia activation leads to a deleterious environment and neurodegeneration. In aged mice, microglia exhibit an increased expression of cytokines and an exacerbated inflammatory response to pathological changes. Whereas LPS increases nitric oxide (NO) secretion in microglia from young mice, induction of reactive oxygen species (ROS) predominates in older mice. Furthermore, there is accumulation of DNA oxidative damage in mitochondria of microglia during aging, and also an increased intracellular ROS production. Increased ROS activates the redox-sensitive nuclear factor kappa B, which promotes more neuroinflammation, and can be translated in functional deficits, such as cognitive impairment. Mitochondria-derived ROS and cathepsin B, are also necessary for the microglial cell production of interleukin-1β, a key inflammatory cytokine. Interestingly, whereas the regulatory cytokine TGFβ1 is also increased in the aged brain, neuroinflammation persists. Assessing this apparent contradiction, we have reported that TGFβ1 induction and activation of Smad3 signaling after inflammatory stimulation are reduced in adult mice. Other protective functions, such as phagocytosis, although observed in aged animals, become not inducible by inflammatory stimuli and TGFβ1. Here, we discuss data suggesting that mitochondrial and endolysosomal dysfunction could at least partially mediate age-associated microglial cell changes, and, together with the impairment of the TGFβ1-Smad3 pathway, could result in the reduction of protective activation and the facilitation of cytotoxic activation of microglia, resulting in the promotion of neurodegenerative diseases.
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Affiliation(s)
- Rommy von Bernhardi
- Department of Neurology, Faculty of Medicine, Pontificia Universidad Católica de Chile Santiago, Chile
| | | | - Jaime Eugenín
- Laboratory of Neural Systems, Department of Biology, Faculty of Chemistry and Biology, Universidad de Santiago de Chile (USACH) Santiago, Chile
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18
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Montes de Oca Balderas P, Aguilera P. A Metabotropic-Like Flux-Independent NMDA Receptor Regulates Ca2+ Exit from Endoplasmic Reticulum and Mitochondrial Membrane Potential in Cultured Astrocytes. PLoS One 2015; 10:e0126314. [PMID: 25954808 PMCID: PMC4425671 DOI: 10.1371/journal.pone.0126314] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 03/31/2015] [Indexed: 01/22/2023] Open
Abstract
Astrocytes were long thought to be only structural cells in the CNS; however, their functional properties support their role in information processing and cognition. The ionotropic glutamate N-methyl D-aspartate (NMDA) receptor (NMDAR) is critical for CNS functions, but its expression and function in astrocytes is still a matter of research and debate. Here, we report immunofluorescence (IF) labeling in rat cultured cortical astrocytes (rCCA) of all NMDAR subunits, with phenotypes suggesting their intracellular transport, and their mRNA were detected by qRT-PCR. IF and Western Blot revealed GluN1 full-length synthesis, subunit critical for NMDAR assembly and transport, and its plasma membrane localization. Functionally, we found an iCa2+ rise after NMDA treatment in Fluo-4-AM labeled rCCA, an effect blocked by the NMDAR competitive inhibitors D(-)-2-amino-5-phosphonopentanoic acid (APV) and Kynurenic acid (KYNA) and dependent upon GluN1 expression as evidenced by siRNA knock down. Surprisingly, the iCa2+ rise was not blocked by MK-801, an NMDAR channel blocker, or by extracellular Ca2+ depletion, indicating flux-independent NMDAR function. In contrast, the IP3 receptor (IP3R) inhibitor XestosponginC did block this response, whereas a Ryanodine Receptor inhibitor did so only partially. Furthermore, tyrosine kinase inhibition with genistein enhanced the NMDA elicited iCa2+ rise to levels comparable to those reached by the gliotransmitter ATP, but with different population dynamics. Finally, NMDA depleted the rCCA mitochondrial membrane potential (mΔψ) measured with JC-1. Our results demonstrate that rCCA express NMDAR subunits which assemble into functional receptors that mediate a metabotropic-like, non-canonical, flux-independent iCa2+ increase.
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Affiliation(s)
- Pavel Montes de Oca Balderas
- Unidad de Neurobiología Dinámica, Departamento de Neuroquímica, Instituto Nacional de Neurología y Neurocirugía, México City, México
- * E-mail:
| | - Penélope Aguilera
- Laboratorio de Patología Vascular Cerebral, Instituto Nacional de Neurología y Neurocirugía, México City, México
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19
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Burjanadze G, Kuchukashvili Z, Chachua M, Menabde K, Dachanidze N, Koshoridze N. Changes in activity of hippocampus creatine kinase under circadian rhythm disorders. BIOL RHYTHM RES 2014. [DOI: 10.1080/09291016.2014.888172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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Baltan S. Excitotoxicity and mitochondrial dysfunction underlie age-dependent ischemic white matter injury. ADVANCES IN NEUROBIOLOGY 2014; 11:151-70. [PMID: 25236728 DOI: 10.1007/978-3-319-08894-5_8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The central nervous system white matter is damaged during an ischemic stroke and therapeutic strategies derived from experimental studies focused exclusively on young adults and gray matter have been unsuccessful in the more clinically relevant aging population. The risk for stroke increases with age and the white matter inherently becomes more susceptible to injury as a function of age. Age-related changes in the molecular architecture of white matter determine the principal injury mechanisms and the functional outcome. A prominent increase in the main plasma membrane Na(+)-dependent glutamate transporter, GLT-1/EAAT2, together with increased extracellular glutamate levels may reflect an increased need for glutamate signaling in the aging white matter to maintain its function. Mitochondria exhibit intricate dynamics to efficiently buffer Ca(2+), to produce sufficient ATP, and to effectively scavenge reactive oxygen species (ROS) in response to excitotoxicity to sustain axon function. Aging exacerbates mitochondrial fusion, leading to progressive alterations in mitochondrial dynamics and function, presumably to effectively buffer increased Ca(2+) load and ROS production. Interestingly, these adaptive adjustments become detrimental under ischemic conditions, leading to increased and early glutamate release and a rapid exhaustion of mitochondrial capacity to sustain energy status of axons. Consequently, protective interventions in young white matter become injurious or ineffective to promote recovery in aging white matter after an ischemic episode. An age-specific understanding of the mechanisms of injury processes in white matter is vital in order to design dynamic therapeutic approaches for stroke victims.
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Affiliation(s)
- Selva Baltan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, NC30, Cleveland, OH, 44195, USA,
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21
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Lourhmati A, Buniatian GH, Paul C, Verleysdonk S, Buecheler R, Buadze M, Proksch B, Schwab M, Gleiter CH, Danielyan L. Age-dependent astroglial vulnerability to hypoxia and glutamate: the role for erythropoietin. PLoS One 2013; 8:e77182. [PMID: 24124607 PMCID: PMC3790708 DOI: 10.1371/journal.pone.0077182] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 09/02/2013] [Indexed: 12/13/2022] Open
Abstract
Extracellular accumulation of toxic concentrations of glutamate (Glu) is a hallmark of many neurodegenerative diseases, often accompanied by hypoxia and impaired metabolism of this neuromediator. To address the question whether the multifunctional neuroprotective action of erythropoietin (EPO) extends to the regulation of extracellular Glu-level and is age-related, young and culture-aged rat astroglial primary cells (APC) were simultaneously treated with 1mM Glu and/or human recombinant EPO under normoxic and hypoxic conditions (NC and HC). EPO increased the Glu uptake by astrocytes under both NC and especially upon HC in culture-aged APC (by 60%). Moreover, treatment with EPO up-regulated the activity of glutamine synthetase (GS), the expression of glutamate-aspartate transporter (GLAST) and the level of EPO mRNA. EPO alleviated the Glu- and hypoxia-induced LDH release from astrocytes. These protective EPO effects were concentration-dependent and they were strongly intensified with age in culture. More than a 4-fold increase in apoptosis and a 2-fold decrease in GS enzyme activity was observed in APC transfected with EPO receptor (EPOR)-siRNA. Our in vivo data show decreased expression of EPO and a strong increase of EPOR in brain homogenates of APP/PS1 mice and their wild type controls during aging. Comparison of APP/PS1 and age-matched WT control mice revealed a stronger expression of EPOR but a weaker one of EPO in the Alzheimer's disease (AD) model mice. Here we show for the first time the direct correlation between the extent of differentiation (age) of astrocytes and the efficacy of EPO in balancing extracellular glutamate clearance and metabolism in an in-vitro model of hypoxia and Glu-induced astroglial injury. The clinical relevance of EPO and EPOR as markers of brain cells vulnerability during aging and neurodegeneration is evidenced by remarkable changes in their expression levels in a transgenic model of AD and their WT controls.
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Affiliation(s)
- Ali Lourhmati
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Tuebingen, Germany
| | - Gayane H. Buniatian
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Tuebingen, Germany
- H. Buniatyan Institute of Biochemistry, National Academy of Sciences, Yerevan, Armenia
| | - Christina Paul
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Tuebingen, Germany
| | | | - Reinhild Buecheler
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Tuebingen, Germany
| | - Marine Buadze
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Tuebingen, Germany
| | - Barbara Proksch
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Tuebingen, Germany
| | - Matthias Schwab
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Tuebingen, Germany
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, University of Tübingen, Stuttgart, Stuttgart, Germany
| | - Christoph H. Gleiter
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Tuebingen, Germany
| | - Lusine Danielyan
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tuebingen, Tuebingen, Germany
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Lu CB, Vreugdenhil M, Toescu EC. The effect of aging-associated impaired mitochondrial status on kainate-evoked hippocampal gamma oscillations. Neurobiol Aging 2012; 33:2692-703. [PMID: 22405041 PMCID: PMC3657166 DOI: 10.1016/j.neurobiolaging.2012.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 12/23/2011] [Accepted: 01/07/2012] [Indexed: 01/08/2023]
Abstract
Oscillations in hippocampal neuronal networks in the gamma frequency band have been implicated in various cognitive tasks and we showed previously that aging reduces the power of such oscillations. Here, using submerged hippocampal slices allowing simultaneous electrophysiological recordings and imaging, we studied the correlation between the kainate-evoked gamma oscillation and mitochondrial activity, as monitored by rhodamine 123. We show that the initiation of kainate-evoked gamma oscillations induces mitochondrial depolarization, indicating a metabolic response. Aging had an opposite effect on these parameters: while depressing the gamma oscillation strength, it increases mitochondrial depolarization. Also, in the aged neurons, kainate induced significantly larger Ca2+ signals. In younger slices, acute mitochondrial depolarization induced by low concentrations of mitochondrial protonophores strongly, but reversibly, inhibits gamma oscillations. These data indicating that the complex network activity required by the maintenance of gamma activity is susceptible to changes and modulations in mitochondrial status.
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Affiliation(s)
| | | | - Emil C. Toescu
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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A reversible early oxidized redox state that precedes macromolecular ROS damage in aging nontransgenic and 3xTg-AD mouse neurons. J Neurosci 2012; 32:5821-32. [PMID: 22539844 DOI: 10.1523/jneurosci.6192-11.2012] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The brain depends on redox electrons from nicotinamide adenine dinucleotide (reduced form; NADH) to produce ATP and oxyradicals (reactive oxygen species [ROS]). Because ROS damage and mitochondrial dysregulation are prominent in aging and Alzheimer's disease (AD) and their relationship to the redox state is unclear, we wanted to know whether an oxidative redox shift precedes these markers and leads to macromolecular damage in a mouse model of AD. We used the 3xTg-AD mouse model, which displays cognitive deficits beginning at 4 months. Hippocampal/cortical neurons were isolated across the age span and cultured in common nutrients to control for possible hormonal and vascular differences. We found an increase of NAD(P)H levels and redox state in nontransgenic (non-Tg) neurons until middle age, followed by a decline in old age. The 3xTg-AD neurons maintained much lower resting NAD(P)H and redox states after 4 months, but the NADH regenerating capacity continuously declined with age beginning at 2 months. These redox characteristics were partially reversible with nicotinamide, a biosynthetic precursor of NAD+. Nicotinamide also protected against glutamate excitotoxicity. Compared with non-Tg neurons, 3xTg-AD neurons had more mitochondria/neuron and lower glutathione (GSH) levels that preceded age-related increases in ROS levels. These GSH deficits were again reversible with nicotinamide in 3xTg-AD neurons. Surprisingly, low macromolecular ROS damage was only elevated after 4 months in the 3xTg-AD neurons if antioxidants were removed. The present data suggest that a more oxidized redox state and a lower antioxidant GSH defense can be dissociated from neuronal ROS damage, changes that precede the onset of cognitive deficits in the 3xTg-AD model.
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von Bernhardi R, Eugenín J. Alzheimer's disease: redox dysregulation as a common denominator for diverse pathogenic mechanisms. Antioxid Redox Signal 2012; 16:974-1031. [PMID: 22122400 DOI: 10.1089/ars.2011.4082] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia and a progressive neurodegeneration that appears to result from multiple pathogenic mechanisms (including protein misfolding/aggregation, involved in both amyloid β-dependent senile plaques and tau-dependent neurofibrillary tangles), metabolic and mitochondrial dysfunction, excitoxicity, calcium handling impairment, glial cell dysfunction, neuroinflammation, and oxidative stress. Oxidative stress, which could be secondary to several of the other pathophysiological mechanisms, appears to be a major determinant of the pathogenesis and progression of AD. The identification of oxidized proteins common for mild cognitive impairment and AD suggests that key oxidation pathways are triggered early and are involved in the initial progression of the neurodegenerative process. Abundant data support that oxidative stress, also considered as a main factor for aging, the major risk factor for AD, can be a common key element capable of articulating the divergent nature of the proposed pathogenic factors. Pathogenic mechanisms influence each other at different levels. Evidence suggests that it will be difficult to define a single-target therapy resulting in the arrest of progression or the improvement of AD deterioration. Since oxidative stress is present from early stages of disease, it appears as one of the main targets to be included in a clinical trial. Exploring the articulation of AD pathogenic mechanisms by oxidative stress will provide clues for better understanding the pathogenesis and progression of this dementing disorder and for the development of effective therapies to treat this disease.
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Affiliation(s)
- Rommy von Bernhardi
- Department of Neurology, Pontificia Universidad Católica de Chile, Santiago, Chile
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25
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Sponsors of SENS5. Rejuvenation Res 2011. [DOI: 10.1089/rej.2011.14.sensabs] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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26
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Dong W, Cheng S, Huang F, Fan W, Chen Y, Shi H, He H. Mitochondrial dysfunction in long-term neuronal cultures mimics changes with aging. Med Sci Monit 2011; 17:BR91-6. [PMID: 21455101 PMCID: PMC3539510 DOI: 10.12659/msm.881706] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Background Aging is a highly complex process that affects various tissues and systems in the body. Senescent changes are relatively more prevalent and severe in the postmitotic cells. Mitochondria play an important role in the aging process. Recently, cell cultures have been widely used as an in vitro model to study aging. The present study was designed to investigate mitochondrial dysfunction associated with aging in a long-term cell culture system. Material/Methods Rat hippocampal neurons were maintained in culture in serum-free medium for 30 days in vitro (DIV). The morphology and development of hippocampal neurons was observed by phase contrast microscope. The levels of cellular senescence were evaluated by cytochemical staining of senescence-associated β-galactosidase (SA-β-Gal) at DIV 5, 10, 15, 20, 25 and 30. In addition, we investigated the changes in mitochondrial membrane potential (Δψm) and intracellular reactive oxygen species (ROS) generation of hippocampal neurons by flow cytometry at different ages. Results The proportion of the senescent cells steadily increased with age in neuron cultures. Δψm decreased gradually with age in long-term culture, while ROS generation increased. Conclusions This study indicates an age-related decrease in mitochondrial function in long-term hippocampal neuronal culture and suggests that DIV 25 neurons could possibly serve as a platform for the future study of anti-aging from the perspective of mitochondrial function.
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Affiliation(s)
- Weiguo Dong
- Department of Integrated Traditional Chinese and Western Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, China
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27
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Abstract
Alzheimer's disease is associated with synapse loss, memory dysfunction, and pathological accumulation of amyloid-β (Aβ) in plaques. However, an exclusively pathological role for Aβ is being challenged by new evidence for an essential function of Aβ at the synapse. Aβ protein exists in different assembly states in the central nervous system and plays distinct roles ranging from synapse and memory formation to memory loss and neuronal cell death. Aβ is present in the brain of symptom-free people where it likely performs important physiological roles. New evidence indicates that synaptic activity directly evokes the release of Aβ at the synapse. At physiological levels, Aβ is a normal, soluble product of neuronal metabolism that regulates synaptic function beginning early in life. Monomeric Aβ40 and Aβ42 are the predominant forms required for synaptic plasticity and neuronal survival. With age, some assemblies of Aβ are associated with synaptic failure and Alzheimer's disease pathology, possibly targeting the N-methyl-D-aspartic acid receptor through the nicotinic acetylcholine receptor, mitochondrial Aβ alcohol dehydrogenase, and cyclophilin D. But emerging data suggests a distinction between age effects on the target response in contrast to the assembly state or the accumulation of the peptide. Both aging and Aβ independently decrease neuronal plasticity. Our laboratory has reported that Aβ, glutamate, and lactic acid are each increasingly toxic with neuron age. The basis of the age-related toxicity partly resides in age-related mitochondrial dysfunction and an oxidative shift in mitochondrial and cytoplasmic redox potential. In turn, signaling through phosphorylated extracellular signal-regulated protein kinases is affected along with an age-independent increase in phosphorylated cAMP response element-binding protein. This review examines the long-awaited functional impact of Aβ on synaptic plasticity.
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Affiliation(s)
- Mordhwaj S Parihar
- School of Studies in Biotechnology & Zoology, Vikram University, Ujjain, MP, India
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28
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Abstract
Dopaminergic neurons of the substantia nigra pars compacta are defective in Parkinson's disease, but the specificity of this dysfunction is not understood. One hypothesis is that mitochondrial bioenergetic capacity is intrinsically lower in striatal dopaminergic presynaptic nerve varicosities, making them unusually susceptible to inhibition of electron transport by oxidative damage. To test this hypothesis, we separated isolated synaptosomes bearing dopamine transporters using immunomagnetic beads and compared their respiration with that of the residual nondopaminergic synaptosomes. As predicted, dopaminergic synaptosomes from striatum had lower respiratory rates. However, so did dopaminergic synaptosomes from cortex, indicating a lack of the predicted striatal specificity. We used fluorescent probes to analyze the bioenergetic competence of individual synaptosomes in the two fractions. The respiratory differences became nonsignificant when respiration rates were normalized to the number of respiration-competent synaptosomes, suggesting that differences reflected the quality of the different fractions. To circumvent damage induced by synaptosomal separation, we monitored membrane potentials in whole unseparated single synaptosomes using fluorescent imaging, and then identified the dopaminergic subpopulation using a fluorescent dopamine transporter substrate (ASP(+) [4-(4-diethylaminostyryl)-N-methylpyridinium iodide]). The capacity of dopaminergic and nondopaminergic synaptosomes to maintain plasma membrane and mitochondrial membrane potential under several stresses did not differ. In addition, this capacity did not decline in either subpopulation with age, a risk factor for Parkinson's disease. We conclude that the intrinsic bioenergetic capacities of dopaminergic and nondopaminergic presynaptic synaptosomes from mice do not differ.
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Brewer GJ. Why vitamin E therapy fails for treatment of Alzheimer's disease. J Alzheimers Dis 2010; 19:27-30. [PMID: 20061623 DOI: 10.3233/jad-2010-1238] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Gregory J Brewer
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, IL 62794-9626, USA.
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30
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Brewer GJ. Epigenetic oxidative redox shift (EORS) theory of aging unifies the free radical and insulin signaling theories. Exp Gerontol 2009; 45:173-9. [PMID: 19945522 DOI: 10.1016/j.exger.2009.11.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 11/17/2009] [Accepted: 11/18/2009] [Indexed: 12/14/2022]
Abstract
Harman's free radical theory of aging posits that oxidized macromolecules accumulate with age to decrease function and shorten life-span. However, nutritional and genetic interventions to boost anti-oxidants have generally failed to increase life-span. Furthermore, the free radical theory fails to explain why exercise causes higher levels of oxyradical damage, but generally promotes healthy aging. The separate anti-aging paradigms of genetic or caloric reductions in the insulin signaling pathway is thought to slow the rate of living to reduce metabolism, but recent evidence from Westbrook and Bartke suggests metabolism actually increases in long-lived mice. To unify these disparate theories and data, here, we propose the epigenetic oxidative redox shift (EORS) theory of aging. According to EORS, sedentary behavior associated with age triggers an oxidized redox shift and impaired mitochondrial function. In order to maintain resting energy levels, aerobic glycolysis is upregulated by redox-sensitive transcription factors. As emphasized by DeGrey, the need to supply NAD(+) for glucose oxidation and maintain redox balance with impaired mitochondrial NADH oxidoreductase requires the upregulation of other oxidoreductases. In contrast to the 2% inefficiency of mitochondrial reduction of oxygen to the oxyradical, these other oxidoreductases enable glycolytic energy production with a deleterious 100% efficiency in generating oxyradicals. To avoid this catastrophic cycle, lactate dehydrogenase is upregulated at the expense of lactic acid acidosis. This metabolic shift is epigenetically enforced, as is insulin resistance to reduce mitochondrial turnover. The low mitochondrial capacity for efficient production of energy reinforces a downward spiral of more sedentary behavior leading to accelerated aging, increased organ failure with stress, impaired immune and vascular functions and brain aging. Several steps in the pathway are amenable to reversal for exit from the vicious cycle of EORS. Examples from our work in the aging rodent brain as well as other aging models are provided.
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Affiliation(s)
- Gregory J Brewer
- Kenneth Stark Endowed Chair in Alzheimer Research, Southern Illinois University School of Medicine, Springfield, IL 62794-9626, USA.
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31
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Jones TT, Brewer GJ. Age-related deficiencies in complex I endogenous substrate availability and reserve capacity of complex IV in cortical neuron electron transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:167-76. [PMID: 19799853 DOI: 10.1016/j.bbabio.2009.09.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 09/22/2009] [Accepted: 09/24/2009] [Indexed: 10/20/2022]
Abstract
Respiratory enzyme complex dysfunction is mechanistically involved in mitochondrial failure leading to neurodegenerative disease, but the pathway is unclear. Here, age-related differences in mitochondrial respiration were measured in both whole and permeabilized neurons from 9-month and 24-month adult rat cortex cultured in common conditions. After permeabilization, respiration increased in both ages of neurons with excess substrates. To dissect specific deficiencies in the respiratory chain, inhibitors for each respiratory chain complex were used to isolate their contributions. Relative to neurons from 9-month rats, in neurons isolated from 24-month rats, complexes I, III, and IV were more sensitive to selective inhibition. Flux control point analysis identified complex I in neurons isolated from 24-month rats as the most sensitive to endogenous substrate availability. The greatest age-related deficit in flux capacity occurred at complex IV with a 29% decrease in neurons isolated from 24-month rats relative to those from 9-month rats. The deficits in complexes I and III may contribute to a redox shift in the quinone pool within the electron transport chain, further extending these age-related deficits. Together these changes could lead to an age-related catastrophic decline in energy production and neuronal death.
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Affiliation(s)
- Torrie T Jones
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, PO Box 19626, Springfield, IL 62794-9626, USA
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32
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Abiram A, Kolandaivel P. Structural analysis and the effect of cyclo(His-Pro) dipeptide on neurotoxins--a dynamics and density functional theory study. J Mol Model 2009; 16:193-202. [PMID: 19554355 DOI: 10.1007/s00894-009-0531-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Accepted: 04/21/2009] [Indexed: 10/20/2022]
Abstract
The switching propensity and maximum probability of occurrence of the side chain imidazole group in the dipeptide cyclo(His-Pro) (CHP) were studied by applying molecular dynamics simulations and density functional theory. The atomistic behaviour of CHP with the neurotoxins glutamate (E) and paraquat (Pq) were also explored; E and Pq engage in hydrogen bond formation with the diketopiperazine (DKP) ring of the dipeptide, with which E shows a profound interaction, as confirmed further by NH and CO stretching vibrational frequencies. The effect of CHP was found to be greater on E than on Pq neurotoxin. A ring puckering study indicated a twist boat conformation for the six-membered DKP ring. Molecular electrostatic potential (MESP) mapping was also used to explore the hydrogen bond interactions prevailing between the neurotoxins and the DKP ring. The results of this study reveal that the DKP ring of the dipeptide CHP can be expected to play a significant role in reducing effects such as oxidative stress and cell death caused by neurotoxins.
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Benedetto A, Au C, Aschner M. Manganese-Induced Dopaminergic Neurodegeneration: Insights into Mechanisms and Genetics Shared with Parkinson’s Disease. Chem Rev 2009; 109:4862-84. [DOI: 10.1021/cr800536y] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Alexandre Benedetto
- Department of Pediatrics, Center for Molecular Neuroscience, Department of Pharmacology, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee 37232-0414
| | - Catherine Au
- Department of Pediatrics, Center for Molecular Neuroscience, Department of Pharmacology, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee 37232-0414
| | - Michael Aschner
- Department of Pediatrics, Center for Molecular Neuroscience, Department of Pharmacology, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee 37232-0414
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34
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Tonkikh AA, Carlen PL. Impaired presynaptic cytosolic and mitochondrial calcium dynamics in aged compared to young adult hippocampal CA1 synapses ameliorated by calcium chelation. Neuroscience 2009; 159:1300-8. [PMID: 19215725 DOI: 10.1016/j.neuroscience.2008.12.057] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 12/17/2008] [Accepted: 12/18/2008] [Indexed: 11/25/2022]
Abstract
Impaired regulation of presynaptic intracellular calcium is thought to adversely affect synaptic plasticity and cognition in the aged brain. We studied presynaptic cytosolic and mitochondrial calcium (Ca) dynamics using axonally loaded Calcium Green-AM and Rhod-2 AM fluorescence respectively in young (2-3 months) and aged (23-26 months) CA3 to CA1 Schaffer collateral excitatory synapses in hippocampal brain slices from Fisher 344 rats. After a tetanus (100 Hz, 200 ms), the presynaptic cytosolic Ca peaked at approximately 10 s in the young and approximately 12 s in the aged synapses. Administration of the membrane permeant Ca chelator, bis (O-aminophenoxy)-ethane-N,N,N,N-tetraacetic acid (BAPTA-AM), significantly attenuated the Ca response in the aged slices, but not in the young slices. The presynaptic mitochondrial Ca signal was much slower, peaking at approximately 90 s in both young and aged synapses, returning to baseline by 300 s. BAPTA-AM significantly attenuated the mitochondrial calcium signal only in the young synapses. Uncoupling mitochondrial respiration by carbonyl cyanide m-chlorophenylhydrazone (CCCP) application evoked a massive intracellular cytosolic Ca increase and a significant drop of mitochondrial Ca, especially in aged slices wherein the cytosolic Ca signal disappeared after approximately 150 s of washout and the mitochondrial Ca signal disappeared after 25 s of washout. These signals were preserved in aged slices by BAPTA-AM. Five minutes of oxygen glucose deprivation (OGD) was associated with a significant increase in cytosolic Ca in both young and aged synapses, which was irreversible in the aged synapses. These responses were significantly attenuated by BAPTA-AM in both the young and aged synapses. These results support the hypothesis that increasing intracellular calcium neuronal buffering in aged rats ameliorates age-related impaired presynaptic Ca regulation.
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Affiliation(s)
- A A Tonkikh
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
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35
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Gupta R, Deshpande SB. 3-Nitropropionic acid-induced depression of spinal reflexes involves mechanisms different from ischemia-induced depression. Brain Res Bull 2008; 77:382-7. [DOI: 10.1016/j.brainresbull.2008.09.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Revised: 09/17/2008] [Accepted: 09/19/2008] [Indexed: 10/21/2022]
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36
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García-Matas S, Gutierrez-Cuesta J, Coto-Montes A, Rubio-Acero R, Díez-Vives C, Camins A, Pallàs M, Sanfeliu C, Cristòfol R. Dysfunction of astrocytes in senescence-accelerated mice SAMP8 reduces their neuroprotective capacity. Aging Cell 2008; 7:630-40. [PMID: 18616637 DOI: 10.1111/j.1474-9726.2008.00410.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Early onset increases in oxidative stress and tau pathology are present in the brain of senescence-accelerated mice prone (SAMP8). Astrocytes play an essential role, both in determining the brain's susceptibility to oxidative damage and in protecting neurons. In this study, we examine changes in tau phosphorylation, oxidative stress and glutamate uptake in primary cultures of cortical astrocytes from neonatal SAMP8 mice and senescence-accelerated-resistant mice (SAMR1). We demonstrated an enhancement of abnormally phosphorylated tau in Ser(199) and Ser(396) in SAMP8 astrocytes compared with that of SAMR1 control mice. Gsk3beta and Cdk5 kinase activity, which regulate tau phosphorylation, was also increased in SAMP8 astrocytes. Inhibition of Gsk3beta by lithium or Cdk5 by roscovitine reduced tau phosphorylation at Ser(396). Moreover, we detected an increase in radical superoxide generation, which may be responsible for the corresponding increase in lipoperoxidation and protein oxidation. We also observed a reduced mitochondrial membrane potential in SAMP8 mouse astrocytes. Glutamate uptake in astrocytes is a critical neuroprotective mechanism. SAMP8 astrocytes showed a decreased glutamate uptake compared with those of SAMR1 controls. Interestingly, survival of SAMP8 or SAMR1 neurons cocultured with SAMP8 astrocytes was significantly reduced. Our results indicate that alterations in astrocyte cultures from SAMP8 mice are similar to those detected in whole brains of SAMP8 mice at 1-5 months. Moreover, our findings suggest that this in vitro preparation is suitable for studying the molecular and cellular processes underlying early aging in this murine model. In addition, our study supports the contention that astrocytes play a key role in neurodegeneration during the aging process.
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Affiliation(s)
- Silvia García-Matas
- Department of Pharmacology and Toxicology, Institut d'Investigacions Biomèdiques de Barcelona, CSIC-IDIBAPS, Barcelona, Spain
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37
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Patel JR, Brewer GJ. Age-related changes to tumor necrosis factor receptors affect neuron survival in the presence of beta-amyloid. J Neurosci Res 2008; 86:2303-13. [PMID: 18418902 DOI: 10.1002/jnr.21663] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Inflammation including local accumulations of tumor necrosis factor alpha (TNF-alpha) is a part of Alzheimer's disease pathology and may exacerbate age-related neurodegeneration. Most studies on TNF-alpha and TNF neuronal receptors are conducted by using embryonic neurons. Few studies consider age-related deficits that may occur in neurons. Age-related changes in susceptibility to TNF-alpha through TNF receptor 1 (TNFR1) and receptor 2 (TNFR2) expression could increase susceptibility to beta-amyloid (1-42, Abeta42). Evidence is conflicting about which receptor mediates survival and/or apoptosis. We determined how aging affects receptor expression in cultured adult rat cortical neurons. Old neurons were more susceptible to Abeta42 toxicity than middle-aged neurons, and the addition of TNF-alpha was neuroprotective in middle-aged neurons, but exacerbated the toxicity from Abeta42 in old neurons. These pathologic and protective responses in old and middle-aged neurons, respectively, correlated with higher starting TNFR1 and TNFR2 mRNA levels in old vs. middle-aged neurons. Middle-aged neurons treated with TNF-alpha plus Abeta42 did not show an increase in either TNFR1 or TNFR2 mRNA, but old neurons showed an up-regulation in TNFR2 mRNA and not TNFR1 mRNA. Despite these mRNA changes, surface immunoreactivity of both TNFR1 and TNFR2 increased with the dose of TNF-alpha in middle-aged neurons. However, middle-aged neurons treated with TNF-alpha plus Abeta42 showed an up-regulation in both TNFR1 and TNFR2 surface expression, whereas old neurons failed to up-regulate surface expression of either receptor. These findings support the hypothesis that age-related changes in TNF-alpha surface receptor expression contribute to the neuronal loss associated with inflammation in Alzheimer's disease.
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Affiliation(s)
- Jigisha R Patel
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University, School of Medicine, Springfield, Illinois 62702, USA
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38
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Jones TT, Brewer GJ. Critical age-related loss of cofactors of neuron cytochrome C oxidase reversed by estrogen. Exp Neurol 2008; 215:212-9. [PMID: 18930048 DOI: 10.1016/j.expneurol.2008.09.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 08/22/2008] [Accepted: 09/11/2008] [Indexed: 11/25/2022]
Abstract
The mechanistic basis for the correlation between mitochondrial dysfunction and neurodegenerative disease is unclear, but evidence supports involvement of cytochrome C oxidase (CCO) deficits with age. Neurons isolated from the brains of 24 month and 9 month rats and cultured in common conditions provide a model of intrinsic neuronal aging. In situ CCO activity was decreased in 24 month neurons relative to 9 month neurons. Possible CCO-related deficits include holoenzyme activity, cofactor, and substrate. No difference was found between neurons from 24 month and 9 month rats in mitochondrial counts per neuron, CCO activity in submitochondrial particles, or basal respiration. Immunostaining for cytochrome C in individual mitochondria revealed an age-related deficit of this electron donor. 24 month neurons did not have adequate respiratory capacity to upregulate respiration after a glutamate stimulus, in spite of a two-fold upregulation of respiration seen in 9 month neurons. Respiration in 24 month neurons was inhibited by lower concentrations of potassium cyanide, suggesting a 50% deficit in functional enzyme in 24 month compared to 9 month neurons. In addition to cytochrome C, CCO requires cardiolipin to function. Staining with nonylacridine orange revealed an age-related deficit in cardiolipin. Treatment of 24 month neurons with 17-beta-estradiol restored cardiolipin levels (10 ng/mL) and upregulated respiration under glutamate stress (1 pg/mL). Attempts to induce mitochondrial turnover by neuronal multiplication also rejuvenated CCO activity in 24 month neurons. These data suggest cytochrome C and cardiolipin levels are deficient in 24 month neurons, preventing normal upregulation of respiration needed for oxidative phosphorylation in response to stress. Furthermore, the data suggest this deficit can be corrected with estrogen treatment.
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Affiliation(s)
- Torrie T Jones
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, 825 Rutledge, Springfield, IL 62702, USA.
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39
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Parihar MS, Kunz EA, Brewer GJ. Age-related decreases in NAD(P)H and glutathione cause redox declines before ATP loss during glutamate treatment of hippocampal neurons. J Neurosci Res 2008; 86:2339-52. [PMID: 18438923 DOI: 10.1002/jnr.21679] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Age-related glutamate excitotoxicity depends in an unknown manner on active mitochondria, which are key determinants of the cellular redox potential. Compared with embryonic and middle-aged neurons, old-aged rat hippocampal neurons have a lower resting reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) and a lower redox ratio (NAD(P)H/flavin adenine nucleotide). Glutamate treatment resulted in an initial increase in NAD(P)H concentrations in all ages, followed by a profound calcium-dependent, age-related decline in NAD(P)H concentration and redox ratio. With complex I of the electron transport chain inhibited by rotenone, treatment with glutamate or ionomycin only resulted in the increase in NAD(P)H fluorescence. High-performance liquid chromatography analysis of adenine nucleotides in brain extracts showed 50% less nicotinamide adenine dinucleotide (NADH) and almost twice as much oxidized nicotinamide adenine dinucleotide, demonstrating a more oxidized ratio in old than middle-aged brain. Resting glutathione content also declined with age and further decreased with glutamate treatment without accompanying changes in adenosine triphosphate levels. We conclude that age does not affect production of NADH by dehydrogenases but that old-aged neurons consume more NADH and glutathione, leading to a catastrophic decline in redox ratio.
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Affiliation(s)
- Mordhwaj S Parihar
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, Illinois 62794-9626, USA
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40
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Patel JR, Brewer GJ. Age-related differences in NFkappaB translocation and Bcl-2/Bax ratio caused by TNFalpha and Abeta42 promote survival in middle-age neurons and death in old neurons. Exp Neurol 2008; 213:93-100. [PMID: 18625500 DOI: 10.1016/j.expneurol.2008.05.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 04/02/2008] [Accepted: 05/02/2008] [Indexed: 01/12/2023]
Abstract
Alzheimer's disease is associated with an age-related accumulation of Abeta and inflammation. The inflammatory mediator, TNFalpha activates a signaling cascade involving NFkappaB translocation to the nucleus and a beneficial or detrimental transcriptional response, depending on the age of the neurons and the type of stress applied. Relative to treatment with Abeta42 alone, previously we found that TNFalpha plus Abeta42, applied to old rat neurons (24 month) is toxic, while the same treatment of middle-age neurons (10 month) is protective. In contrast to improved survival of middle-age rat cortical neurons, neurons from old rats are killed by TNFalpha plus Abeta42 despite greater p50 nuclear translocation. In middle-age neurons, blocking TNFR1 does not affect NFkappaB translocation, whereas blocking TNFR2 results in an increase in NFkappaB translocation. For old neurons, blocking either receptor, does not change NFkappaB translocation, but improves cell survival. To account for these effects on cell viability in response to TNF+Abeta, measures of the Bcl-2/Bax ratio positively correlate with survival. In the setting of old neurons, these results suggest that overactivated nuclear translocation of NFkappaB and lower Bcl-2 levels promote death that is reduced by inhibition of either TNFR1 or R2.
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Affiliation(s)
- Jigisha R Patel
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University, School of Medicine, Springfield, IL, USA
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41
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Cyclo(His-Pro) promotes cytoprotection by activating Nrf2-mediated up-regulation of antioxidant defence. J Cell Mol Med 2008; 13:1149-61. [PMID: 18373731 PMCID: PMC4496110 DOI: 10.1111/j.1582-4934.2008.00326.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Hystidyl-proline [cyclo(His-Pro)] is an endogenous cyclic dipeptide produced by the cleavage of thyrotropin releasing hormone. Previous studies have shown that cyclo(His-Pro) protects against oxidative stress, although the underlying mechanism has remained elusive. Here, we addressed this issue and found that cyclo(His-Pro) triggered nuclear accumulation of NF-E2-related factor-2 (Nrf2), a transcription factor that up-regulates antioxidant-/electrophile-responsive element (ARE-EpRE)-related genes, in PC12 cells. Cyclo(His-Pro) attenuated reactive oxygen species production, and prevented glutathione depletion caused by glutamate, rotenone, paraquat and β-amyloid treatment. Moreover, real-time PCR analyses revealed that cyclo(His-Pro) induced the expression of a number of ARE-related genes and protected cells against hydrogen peroxide-mediated apoptotic death. Furthermore, these effects were abolished by RNA interference-mediated Nrf2 knockdown. Finally, pharmacological inhibition of p-38 MAPK partially prevented both cyclo(His-Pro)-mediated Nrf2 activation and cellular protection. These results suggest that the signalling mechanism responsible for the cytoprotective actions of cyclo(His-Pro) would involve p-38 MAPK activation leading to Nrf2-mediated up-regulation of antioxidant cellular defence.
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42
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Larsen GA, Skjellegrind HK, Vinje ML, Berg-Johnsen J. Mitochondria are More Resistant to Hypoxic Depolarization in the Newborn than in the Adult Brain. Neurochem Res 2008; 33:1894-900. [DOI: 10.1007/s11064-008-9664-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Accepted: 03/11/2008] [Indexed: 11/29/2022]
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43
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Parihar MS, Parihar A, Chen Z, Nazarewicz R, Ghafourifar P. mAtNOS1 regulates mitochondrial functions and apoptosis of human neuroblastoma cells. Biochim Biophys Acta Gen Subj 2008; 1780:921-6. [PMID: 18359297 DOI: 10.1016/j.bbagen.2008.02.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2008] [Revised: 02/19/2008] [Accepted: 02/19/2008] [Indexed: 01/11/2023]
Abstract
mAtNOS1 is a novel gene recently reported in mammalian cells with functions that are not fully understood. The present study generated human neuroblastoma SHSY cells over- and underexpressing mAtNOS1 and shows that mAtNOS1 is involved in regulating mitochondrial nitric oxide, mitochondrial transmembrane potential, protein tyrosine nitration, cytochrome c release, and apoptosis of those cells.
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Affiliation(s)
- Mordhwaj S Parihar
- Department of Surgery, Davis Heart & Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
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44
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Parihar MS, Parihar A, Villamena FA, Vaccaro PS, Ghafourifar P. Inactivation of mitochondrial respiratory chain complex I leads mitochondrial nitric oxide synthase to become pro-oxidative. Biochem Biophys Res Commun 2008; 367:761-7. [DOI: 10.1016/j.bbrc.2008.01.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Accepted: 01/04/2008] [Indexed: 11/29/2022]
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45
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Persistent mitochondrial dysfunction and oxidative stress hinder neuronal cell recovery from reversible proteasome inhibition. Apoptosis 2008; 13:588-99. [DOI: 10.1007/s10495-008-0182-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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46
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Shokouhi G, Tubbs RS, Shoja MM, Roshangar L, Mesgari M, Ghorbanihaghjo A, Ahmadi N, Sheikhzadeh F, Rad JS. The effects of aerobic exercise training on the age-related lipid peroxidation, Schwann cell apoptosis and ultrastructural changes in the sciatic nerve of rats. Life Sci 2008; 82:840-6. [PMID: 18336840 DOI: 10.1016/j.lfs.2008.01.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 12/10/2007] [Accepted: 01/25/2008] [Indexed: 12/20/2022]
Abstract
The potential role of exercise in preventing the age-related spontaneous peripheral neuropathy has not been studied. We examined the effects of long-term aerobic exercise training on lipid peroxidation, Schwann cell (SC) apoptosis and ultrastructural changes in the sciatic nerve of rats during aging. Three groups of 12-week old Wistar rats ran on a treadmill for 6, 9 and 12 months (exercise trained (ET) group, n=10 each) according to an exercise training program targeted at a speed of 22 m/min (at 7 degrees incline), 60 min/day, 6 days/week. Three corresponding groups of untrained rats were used as the controls (sedentary (SED) group). At the end of each period, sciatic nerve biopsies were performed, and processed for biochemical, immunohistochemical and ultrastructural analyses. The results showed that aging was associated with an increased level of nerve malondialdehyde (MDA, marker of lipid peroxidation) and a higher number of SC apoptosis in SED group. The SED group showed irregular nerve fibers with thin myelin sheaths and areas of myelin-axon detachment. However, the ET group had significantly diminished nerve lipid peroxidation and SC apoptosis. In the ET group, nerve fibers had a thick myelin sheath with frequent folding. These findings suggest that aerobic exercise training protects peripheral nerves by attenuating oxidative reactions, and preserving SCs and myelin sheath from pathologic changes, which occur during normal aging.
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Affiliation(s)
- Ghaffar Shokouhi
- Department of Neurosurgery, Tabriz University of Medical Sciences, Tabriz, Iran
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Ballard JWO, Katewa SD, Melvin RG, Chan G. Comparative analysis of mitochondrial genotype and aging. Ann N Y Acad Sci 2007; 1114:93-106. [PMID: 17934050 DOI: 10.1196/annals.1396.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A common feature across all animals, including humans, is that mitochondrial bioenergetics is linked to oxidative stress, but the nature of these relationships with survival is yet to be properly defined. In this study we included 12 Drosophila simulans isofemale lines: four of each distinct mtDNA haplogroup (siI, -II, and -III). First, we investigated sequence variation in six mtDNA and 13 nuclear encoded genes (nine nuclear-encoded subunits, and the four known isoforms, of complex IV of the electron transport chain). As expected we observed high divergence among the three distinct mitotypes and greatest mtDNA variability in siII-harboring flies. In the nuclear encoded genes, no fixed amino acid differences were observed and levels of polymorphism did not differ significantly among flies harboring distinct mtDNA types. Second, 15,456 flies were included in mortality studies. We observed that mtDNA type influenced survival (siII approximately siIII > siI), flies harboring siII mtDNA had the greatest variation in mortality rates, and in all cases males were longer lived than females. We also assayed maximal rates of hydrogen peroxide (H(2)O(2)) production from complex III of the electron transport chain in mitochondria isolated from 11-day-old flies. Contrary to our prediction, rates of H(2)O(2) production tended to increase with mean survival. This result suggests that higher rates of H(2)O(2) production in younger flies may lead to an upregulation of antioxidants, age-dependent increase in the rate of H(2)O(2) production differ, and/or flies vary in their mitochondrial uncoupling. Alternatively, the whole organism may not regularly, if ever, experience maximal H(2)O(2) production rates.
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Affiliation(s)
- J William O Ballard
- Ramaciotti Centre for Gene Function Analysis, School of Biotechnology and Biomolecular Sciences, 217B Biology Building, University of New South Wales, Sydney, NSW, Australia 2052.
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Abstract
Here we present a protocol for extraction and culture of neurons from adult rat or mouse CNS. The method proscribes an optimized protease digestion of slices, control of osmolarity and pH outside the incubator with Hibernate and density gradient separation of neurons from debris. This protocol produces yields of millions of cortical, hippocampal neurons or neurosphere progenitors from each brain. The entire process of neuron isolation and culture takes less than 4 h. With suitable growth factors, adult neuron regeneration of axons and dendrites in culture proceeds over 1-3 weeks to allow controlled studies in pharmacology, electrophysiology, development, regeneration and neurotoxicology. Adult neurospheres can be collected in 1 week as a source of neuroprogenitors ethically preferred over embryonic or fetal sources. This protocol emphasizes two differences between neuron differentiation and neurosphere proliferation: adhesion dependence and the differentiating power of retinyl acetate.
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Affiliation(s)
- Gregory J Brewer
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, Illinois 62794-9626, USA.
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