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Chaves-Coira I, García-Magro N, Zegarra-Valdivia J, Torres-Alemán I, Núñez Á. Cognitive Deficits in Aging Related to Changes in Basal Forebrain Neuronal Activity. Cells 2023; 12:1477. [PMID: 37296598 PMCID: PMC10252596 DOI: 10.3390/cells12111477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 05/22/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
Aging is a physiological process accompanied by a decline in cognitive performance. The cholinergic neurons of the basal forebrain provide projections to the cortex that are directly engaged in many cognitive processes in mammals. In addition, basal forebrain neurons contribute to the generation of different rhythms in the EEG along the sleep/wakefulness cycle. The aim of this review is to provide an overview of recent advances grouped around the changes in basal forebrain activity during healthy aging. Elucidating the underlying mechanisms of brain function and their decline is especially relevant in today's society as an increasingly aged population faces higher risks of developing neurodegenerative diseases such as Alzheimer's disease. The profound age-related cognitive deficits and neurodegenerative diseases associated with basal forebrain dysfunction highlight the importance of investigating the aging of this brain region.
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Affiliation(s)
- Irene Chaves-Coira
- Department of Anatomy, Histology and Neurosciences, Universidad Autónoma de Madrid, 28029 Madrid, Spain;
| | - Nuria García-Magro
- Facultad de Ciencias de la Salud, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223 Madrid, Spain;
| | - Jonathan Zegarra-Valdivia
- Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain; (J.Z.-V.); (I.T.-A.)
- Facultad de Ciencias de la Salud, Universidad Señor de Sipán, Chiclayo 02001, Peru
| | - Ignacio Torres-Alemán
- Achucarro Basque Center for Neuroscience, 48940 Leioa, Spain; (J.Z.-V.); (I.T.-A.)
- Ikerbasque Science Foundation, 48009 Bilbao, Spain
| | - Ángel Núñez
- Department of Anatomy, Histology and Neurosciences, Universidad Autónoma de Madrid, 28029 Madrid, Spain;
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Anusha-Kiran Y, Mol P, Dey G, Bhat FA, Chatterjee O, Deolankar SC, Philip M, Prasad TSK, Srinivas Bharath MM, Mahadevan A. Regional heterogeneity in mitochondrial function underlies region specific vulnerability in human brain ageing: Implications for neurodegeneration. Free Radic Biol Med 2022; 193:34-57. [PMID: 36195160 DOI: 10.1016/j.freeradbiomed.2022.09.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/12/2022] [Accepted: 09/22/2022] [Indexed: 12/01/2022]
Abstract
Selective neuronal vulnerability (SNV) of specific neuroanatomical regions such as frontal cortex (FC) and hippocampus (HC) is characteristic of age-associated neurodegenerative diseases (NDDs), although its pathogenetic basis remains unresolved. We hypothesized that physiological differences in mitochondrial function in neuroanatomical regions could contribute to SNV. To investigate this, we evaluated mitochondrial function in human brains (age range:1-90 y) in FC, striatum (ST), HC, cerebellum (CB) and medulla oblongata (MD), using enzyme assays and quantitative proteomics. Striking differences were noted in resistant regions- MD and CB compared to the vulnerable regions- FC, HC and ST. At younger age (25 ± 5 y), higher activity of electron transport chain enzymes and upregulation of metabolic and antioxidant proteins were noted in MD compared to FC and HC, that was sustained with increasing age (≥65 y). In contrast, the expression of synaptic proteins was higher in FC, HC and ST (vs. MD). In line with this, quantitative phospho-proteomics revealed activation of upstream regulators (ERS, PPARα) of mitochondrial metabolism and inhibition of synaptic pathways in MD. Microtubule Associated Protein Tau (MAPT) showed overexpression in FC, HC and ST both in young and older age (vs. MD). MAPT hyperphosphorylation and the activation of its kinases were noted in FC and HC with age. Our study demonstrates that regional heterogeneity in mitochondrial and other cellular functions contribute to SNV and protect regions such as MD, while rendering FC and HC vulnerable to NDDs. The findings also support the "last in, first out" hypothesis of ageing, wherein regions such as FC, that are the most recent to develop phylogenetically and ontogenetically, are the first to be affected in ageing and NDDs.
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Affiliation(s)
- Yarlagadda Anusha-Kiran
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), No. 2900, Hosur Road, Bangalore, 560029, India; Department of Clinical Psychopharmacology and Neurotoxicology, NIMHANS, No. 2900, Hosur Road, Bangalore, 560029, India
| | - Praseeda Mol
- Institute of Bioinformatics, International Technology Park, White Field, Bangalore, 560066, India; Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam, 690525, India
| | - Gourav Dey
- Institute of Bioinformatics, International Technology Park, White Field, Bangalore, 560066, India
| | - Firdous Ahmad Bhat
- Institute of Bioinformatics, International Technology Park, White Field, Bangalore, 560066, India
| | - Oishi Chatterjee
- Institute of Bioinformatics, International Technology Park, White Field, Bangalore, 560066, India; Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam, 690525, India
| | - Sayali Chandrashekhar Deolankar
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, 575018, India
| | - Mariamma Philip
- Department of Biostatistics, NIMHANS, No. 2900, Hosur Road, Bangalore, 560029, India
| | - T S Keshava Prasad
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, 575018, India.
| | - M M Srinivas Bharath
- Department of Clinical Psychopharmacology and Neurotoxicology, NIMHANS, No. 2900, Hosur Road, Bangalore, 560029, India.
| | - Anita Mahadevan
- Department of Neuropathology, National Institute of Mental Health and Neurosciences (NIMHANS), No. 2900, Hosur Road, Bangalore, 560029, India.
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Sutherland TC, Sefiani A, Horvat D, Huntington TE, Lei Y, West AP, Geoffroy CG. Age-Dependent Decline in Neuron Growth Potential and Mitochondria Functions in Cortical Neurons. Cells 2021; 10:1625. [PMID: 34209640 PMCID: PMC8306398 DOI: 10.3390/cells10071625] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 12/23/2022] Open
Abstract
The age of incidence of spinal cord injury (SCI) and the average age of people living with SCI is continuously increasing. However, SCI is extensively modeled in young adult animals, hampering translation of research to clinical applications. While there has been significant progress in manipulating axon growth after injury, the impact of aging is still unknown. Mitochondria are essential to successful neurite and axon growth, while aging is associated with a decline in mitochondrial functions. Using isolation and culture of adult cortical neurons, we analyzed mitochondrial changes in 2-, 6-, 12- and 18-month-old mice. We observed reduced neurite growth in older neurons. Older neurons also showed dysfunctional respiration, reduced membrane potential, and altered mitochondrial membrane transport proteins; however, mitochondrial DNA (mtDNA) abundance and cellular ATP were increased. Taken together, these data suggest that dysfunctional mitochondria in older neurons may be associated with the age-dependent reduction in neurite growth. Both normal aging and traumatic injury are associated with mitochondrial dysfunction, posing a challenge for an aging SCI population as the two elements can combine to worsen injury outcomes. The results of this study highlight this as an area of great interest in CNS trauma.
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Affiliation(s)
- Theresa C. Sutherland
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, Bryan, TX 77807, USA; (T.C.S.); (A.S.); (D.H.); (T.E.H.)
| | - Arthur Sefiani
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, Bryan, TX 77807, USA; (T.C.S.); (A.S.); (D.H.); (T.E.H.)
| | - Darijana Horvat
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, Bryan, TX 77807, USA; (T.C.S.); (A.S.); (D.H.); (T.E.H.)
| | - Taylor E. Huntington
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, Bryan, TX 77807, USA; (T.C.S.); (A.S.); (D.H.); (T.E.H.)
| | - Yuanjiu Lei
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA; (Y.L.); (A.P.W.)
| | - A. Phillip West
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan, TX 77807, USA; (Y.L.); (A.P.W.)
| | - Cédric G. Geoffroy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, Bryan, TX 77807, USA; (T.C.S.); (A.S.); (D.H.); (T.E.H.)
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Habich A, Fehér KD, Antonenko D, Boraxbekk CJ, Flöel A, Nissen C, Siebner HR, Thielscher A, Klöppel S. Stimulating aged brains with transcranial direct current stimulation: Opportunities and challenges. Psychiatry Res Neuroimaging 2020; 306:111179. [PMID: 32972813 DOI: 10.1016/j.pscychresns.2020.111179] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 06/30/2020] [Accepted: 09/03/2020] [Indexed: 02/06/2023]
Abstract
Ageing involves significant neurophysiological changes that are both systematic while at the same time exhibiting divergent trajectories across individuals. These changes underlie cognitive impairments in elderly while also affecting the response of aged brains to interventions like transcranial direct current stimulation (tDCS). While the cognitive benefits of tDCS are more variable in elderly, older adults also respond differently to stimulation protocols compared to young adults. The age-related neurophysiological changes influencing the responsiveness to tDCS remain to be addressed in-depth. We review and discuss the premise that, in comparison to the better calibrated brain networks present in young adults, aged systems perform further away from a homoeostatic set-point. We argue that this age-related neurophysiological deviation from the homoeostatic optimum extends the leeway for tDCS to modulate the aged brain. This promotes the potency of immediate tDCS effects to induce directional plastic changes towards the homoeostatic equilibrium despite the impaired plasticity induction in elderly. We also consider how age-related neurophysiological changes pose specific challenges for tDCS that necessitate proper adaptations of stimulation protocols. Appreciating the distinctive properties of aged brains and the accompanying adjustment of stimulation parameters can increase the potency and reliability of tDCS as a treatment avenue in older adults.
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Affiliation(s)
- Annegret Habich
- University Hospital of Old Age Psychiatry and Psychotherpa, University of Bern, Bolligenstrasse 111, 3000 Bern, Switzerland; Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany.
| | - Kristoffer D Fehér
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Bolligenstrasse 111, 3000 Bern, Switzerland
| | - Daria Antonenko
- Department of Neurology, University of Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany
| | - Carl-Johan Boraxbekk
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Østvej, 2650 Hvidovre, Denmark; Department of Radiation Sciences, Umeå University, 90187 Umeå, Sweden; Institute of Sports Medicine Copenhagen (ISMC), Copenhagen University Hospital Bispebjerg, Bispebjerg Bakke 23, 2400 Copenhagen, Denmark
| | - Agnes Flöel
- Department of Neurology, University of Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany; German Center for Neurodegenerative Diseases, Ellernholzstraße 1-2, 17489 Greifswald, Germany
| | - Christoph Nissen
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Bolligenstrasse 111, 3000 Bern, Switzerland; Department of Psychiatry and Psychotherapy, Faculty of Medicine, University of Freiburg, Hauptstraße 5, 79104 Freiburg, Germany
| | - Hartwig Roman Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Østvej, 2650 Hvidovre, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg, Bispebjerg Bakke 23, 2400 Copenhagen, Denmark; Institute for Clinical Medicine, Faculty of Medical and Health Sciences, University of Copenhagen, Nørre Allé 20, 2200 Copenhagen, Denmark
| | - Axel Thielscher
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Østvej, 2650 Hvidovre, Denmark; Department of Electrical Engineering, Technical University of Denmark, Ørsteds Pl. 348, 2800 Kgs. Lyngby, Denmark
| | - Stefan Klöppel
- University Hospital of Old Age Psychiatry and Psychotherpa, University of Bern, Bolligenstrasse 111, 3000 Bern, Switzerland
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5
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Jung H, Kim SY, Canbakis Cecen FS, Cho Y, Kwon SK. Dysfunction of Mitochondrial Ca 2+ Regulatory Machineries in Brain Aging and Neurodegenerative Diseases. Front Cell Dev Biol 2020; 8:599792. [PMID: 33392190 PMCID: PMC7775422 DOI: 10.3389/fcell.2020.599792] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 11/06/2020] [Indexed: 12/20/2022] Open
Abstract
Calcium ions (Ca2+) play critical roles in neuronal processes, such as signaling pathway activation, transcriptional regulation, and synaptic transmission initiation. Therefore, the regulation of Ca2+ homeostasis is one of the most important processes underlying the basic cellular viability and function of the neuron. Multiple components, including intracellular organelles and plasma membrane Ca2+-ATPase, are involved in neuronal Ca2+ control, and recent studies have focused on investigating the roles of mitochondria in synaptic function. Numerous mitochondrial Ca2+ regulatory proteins have been identified in the past decade, with studies demonstrating the tissue- or cell-type-specific function of each component. The mitochondrial calcium uniporter and its binding subunits are major inner mitochondrial membrane proteins contributing to mitochondrial Ca2+ uptake, whereas the mitochondrial Na+/Ca2+ exchanger (NCLX) and mitochondrial permeability transition pore (mPTP) are well-studied proteins involved in Ca2+ extrusion. The level of cytosolic Ca2+ and the resulting characteristics of synaptic vesicle release properties are controlled via mitochondrial Ca2+ uptake and release at presynaptic sites, while in dendrites, mitochondrial Ca2+ regulation affects synaptic plasticity. During brain aging and the progress of neurodegenerative disease, mitochondrial Ca2+ mishandling has been observed using various techniques, including live imaging of Ca2+ dynamics. Furthermore, Ca2+ dysregulation not only disrupts synaptic transmission but also causes neuronal cell death. Therefore, understanding the detailed pathophysiological mechanisms affecting the recently discovered mitochondrial Ca2+ regulatory machineries will help to identify novel therapeutic targets. Here, we discuss current research into mitochondrial Ca2+ regulatory machineries and how mitochondrial Ca2+ dysregulation contributes to brain aging and neurodegenerative disease.
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Affiliation(s)
- Hyunsu Jung
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea.,Division of Life Sciences, Korea University, Seoul, South Korea
| | - Su Yeon Kim
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea.,Department of Biomedical Sciences, College of Medicine, Korea University, Seoul, South Korea
| | - Fatma Sema Canbakis Cecen
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea.,Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, South Korea
| | - Yongcheol Cho
- Division of Life Sciences, Korea University, Seoul, South Korea
| | - Seok-Kyu Kwon
- Center for Functional Connectomics, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea.,Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul, South Korea
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6
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Ghoweri AO, Ouillette L, Frazier HN, Anderson KL, Lin RL, Gant JC, Parent R, Moore S, Murphy GG, Thibault O. Electrophysiological and Imaging Calcium Biomarkers of Aging in Male and Female 5×FAD Mice. J Alzheimers Dis 2020; 78:1419-1438. [PMID: 33164928 PMCID: PMC7836067 DOI: 10.3233/jad-200109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND In animal models and tissue preparations, calcium dyshomeostasis is a biomarker of aging and Alzheimer's disease that is associated with synaptic dysfunction, neuritic pruning, and dysregulated cellular processes. It is unclear, however, whether the onset of calcium dysregulation precedes, is concurrent with, or is the product of pathological cellular events (e.g., oxidation, amyloid-β production, and neuroinflammation). Further, neuronal calcium dysregulation is not always present in animal models of amyloidogenesis, questioning its reliability as a disease biomarker. OBJECTIVE Here, we directly tested for the presence of calcium dysregulation in dorsal hippocampal neurons in male and female 5×FAD mice on a C57BL/6 genetic background using sharp electrodes coupled with Oregon-green Bapta-1 imaging. We focused on three ages that coincide with the course of amyloid deposition: 1.5, 4, and 10 months old. METHODS Outcome variables included measures of the afterhyperpolarization, short-term synaptic plasticity, and calcium kinetics during synaptic activation. Quantitative analyses of spatial learning and memory were also conducted using the Morris water maze. Main effects of sex, age, and genotype were identified on measures of electrophysiology and calcium imaging. RESULTS Measures of resting Oregon-green Bapta-1 fluorescence showed significant reductions in the 5×FAD group compared to controls. Deficits in spatial memory, along with increases in Aβ load, were detectable at older ages, allowing us to test for temporal associations with the onset of calcium dysregulation. CONCLUSION Our results provide evidence that reduced, rather than elevated, neuronal calcium is identified in this 5×FAD model and suggests that this surprising result may be a novel biomarker of AD.
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Affiliation(s)
- Adam O Ghoweri
- UKMC MS313, Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Lara Ouillette
- 5037 BSRB, Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Hilaree N Frazier
- UKMC MS313, Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Katie L Anderson
- UKMC MS313, Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Ruei-Lung Lin
- UKMC MS313, Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - John C Gant
- UKMC MS313, Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Rachel Parent
- 5037 BSRB, Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Shannon Moore
- 5037 BSRB, Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.,5037 BSRB, Molecular and Integrative Physiology, Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
| | - Geoffrey G Murphy
- 5037 BSRB, Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.,5037 BSRB, Molecular and Integrative Physiology, Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
| | - Olivier Thibault
- UKMC MS313, Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
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7
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Shiraishi H, Yamada K, Oki E, Ishige M, Fukao T, Hamada Y, Sakai N, Ochi F, Watanabe A, Kawakami S, Kuzume K, Watanabe K, Sameshima K, Nakamagoe K, Tamaoka A, Asahina N, Yokoshiki S, Miyakoshi T, Oba K, Isoe T, Hayashi H, Yamaguchi S, Sato N. Open-label clinical trial of bezafibrate treatment in patients with fatty acid oxidation disorders in Japan; 2nd report QOL survey. Mol Genet Metab Rep 2019; 20:100496. [PMID: 31372341 PMCID: PMC6661278 DOI: 10.1016/j.ymgmr.2019.100496] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 07/14/2019] [Accepted: 07/14/2019] [Indexed: 12/31/2022] Open
Abstract
Introduction Fatty acid oxidation disorders (FAODs) are rare diseases caused by a defective mitochondrial fatty acid oxidation (FAO) enzyme. We recently reported that bezafibrate improved patient quality of life (QOL) based on the SF-36 questionnaire score in patients with FAODs during a 50-week, open-label, clinical trial. Herein we conducted further survey assessments of the trial patients to define the long-term efficacy and safety of bezafibrate. Materials and methods This trial was an open-label, non-randomized, and multicenter study of bezafibrate treatment in five patients with very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency and one patient with carnitine palmitoyltransferase-II (CPT-2) deficiency (median age, 15.9 years; range, 5.8-26.4 years). The bezafibrate administration was continued for a further 102-174 weeks after the 24-week treatment described in our previous study. QOL was quantitated using the 36-Item Short Form Health Survey (SF-36) questionnaire, which constitutes eight components: physical functioning (PF), role limitation due to physical problems, bodily pain, general health perception, vitality, social functioning, role limitation due to emotional problems, and mental health. Results PF was elevated in all patients and continued to rise during the study, with the total QOL scores increased from baseline in five of the six cases. In particular, three patients older than 20 years showed treatment efficacy, and all subcategories of QOL were elevated in two of these cases. Conclusion Our findings supported one of the stated benefits of bezafibrate in improving QOL for patients with FAODs.
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Affiliation(s)
- Hideaki Shiraishi
- Department of Pediatrics, Hokkaido University School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan
| | - Kenji Yamada
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1, En-ya-cho, Izumo, Shimane 693-8501, Japan
| | - Eishin Oki
- Department of Pediatrics, Tsugaru General Hospital, 12-3, Iwaki-cho, Goshogawara, Aomori 037-0074, Japan
| | - Mika Ishige
- Department of Pediatrics and Child Health, Nihon University School of Medicine, 1-6, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8309, Japan
| | - Toshiyuki Fukao
- Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1, Yanagido, Gifu 501-1194, Japan
| | - Yusuke Hamada
- Child Healthcare and Genetic Science Laboratory, Division of Health Sciences, Osaka University Graduate School of Medicine, 1-7 Yamada-oka, Suita, Osaka 565-0871, Japan.,Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization, 4-2-78, Fukushima, Fukushima-ku, Osaka 553-0003, Japan
| | - Norio Sakai
- Child Healthcare and Genetic Science Laboratory, Division of Health Sciences, Osaka University Graduate School of Medicine, 1-7 Yamada-oka, Suita, Osaka 565-0871, Japan.,Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization, 4-2-78, Fukushima, Fukushima-ku, Osaka 553-0003, Japan
| | - Fumihiro Ochi
- Department of Pediatrics, Yawatahama City General Hospital, 638, Ohira-ichibankochi, Yawatahama, Ehime 796-8502, Japan.,Department of Pediatrics, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan
| | - Asami Watanabe
- Department of Pediatrics, Yawatahama City General Hospital, 638, Ohira-ichibankochi, Yawatahama, Ehime 796-8502, Japan.,Department of Pediatrics, Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan
| | - Sanae Kawakami
- Department of Pediatrics, Yawatahama City General Hospital, 638, Ohira-ichibankochi, Yawatahama, Ehime 796-8502, Japan
| | - Kazuyo Kuzume
- Department of Pediatrics, Yawatahama City General Hospital, 638, Ohira-ichibankochi, Yawatahama, Ehime 796-8502, Japan.,Department of Community and Emergency Medicine, Ehime University School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan
| | - Kenji Watanabe
- Department of Pediatrics, Kagoshima City Hospital, 37-1, Uearata-cho, Kagoshima 890-8760, Japan
| | - Koji Sameshima
- Department of Pediatrics, Kagoshima City Hospital, 37-1, Uearata-cho, Kagoshima 890-8760, Japan
| | - Kiyotaka Nakamagoe
- Department of Neurology, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1, Tennoudai, Tsukuba, Ibaraki 305-8575, Japan
| | - Akira Tamaoka
- Department of Neurology, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1, Tennoudai, Tsukuba, Ibaraki 305-8575, Japan
| | - Naoko Asahina
- Department of Pediatrics, Hokkaido University School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan
| | - Saki Yokoshiki
- Hokkaido University Hospital Clinical Research and Medical Innovation Center, Research and Development Division, North 14, West 5, Kita-ku, Sapporo 060-8648, Japan
| | - Takashi Miyakoshi
- Hokkaido University Hospital Clinical Research and Medical Innovation Center, Research and Development Division, North 14, West 5, Kita-ku, Sapporo 060-8648, Japan
| | - Koji Oba
- Department of Biostatistics, School of Public Health, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Toshiyuki Isoe
- Hokkaido University Hospital Clinical Research and Medical Innovation Center, Research and Development Division, North 14, West 5, Kita-ku, Sapporo 060-8648, Japan
| | - Hiroshi Hayashi
- Hokkaido University Hospital Clinical Research and Medical Innovation Center, Research and Development Division, North 14, West 5, Kita-ku, Sapporo 060-8648, Japan
| | - Seiji Yamaguchi
- Department of Pediatrics, Shimane University Faculty of Medicine, 89-1, En-ya-cho, Izumo, Shimane 693-8501, Japan
| | - Norihiro Sato
- Hokkaido University Hospital Clinical Research and Medical Innovation Center, North 14, West 5, Kita-ku, Sapporo 060-8648, Japan
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8
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McGuire PJ. Mitochondrial Dysfunction and the Aging Immune System. BIOLOGY 2019; 8:biology8020026. [PMID: 31083529 PMCID: PMC6627503 DOI: 10.3390/biology8020026] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/04/2019] [Accepted: 01/16/2019] [Indexed: 01/28/2023]
Abstract
Mitochondria are ancient organelles that have co-evolved with their cellular hosts, developing a mutually beneficial arrangement. In addition to making energy, mitochondria are multifaceted, being involved in heat production, calcium storage, apoptosis, cell signaling, biosynthesis, and aging. Many of these mitochondrial functions decline with age, and are the basis for many diseases of aging. Despite the vast amount of research dedicated to this subject, the relationship between aging mitochondria and immune function is largely absent from the literature. In this review, three main issues facing the aging immune system are discussed: (1) inflamm-aging; (2) susceptibility to infection and (3) declining T-cell function. These issues are re-evaluated using the lens of mitochondrial dysfunction with aging. With the recent expansion of numerous profiling technologies, there has been a resurgence of interest in the role of metabolism in immunity, with mitochondria taking center stage. Building upon this recent accumulation of knowledge in immunometabolism, this review will advance the hypothesis that the decline in immunity and associated pathologies are partially related to the natural progression of mitochondrial dysfunction with aging.
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Affiliation(s)
- Peter J McGuire
- Metabolism, Infection and Immunity Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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9
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Freitas HR, Ferreira GDC, Trevenzoli IH, Oliveira KDJ, de Melo Reis RA. Fatty Acids, Antioxidants and Physical Activity in Brain Aging. Nutrients 2017; 9:nu9111263. [PMID: 29156608 PMCID: PMC5707735 DOI: 10.3390/nu9111263] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 11/11/2017] [Accepted: 11/14/2017] [Indexed: 12/25/2022] Open
Abstract
Polyunsaturated fatty acids and antioxidants are important mediators in the central nervous system. Lipid derivatives may control the production of proinflammatory agents and regulate NF-κB activity, microglial activation, and fatty acid oxidation; on the other hand, antioxidants, such as glutathione and ascorbate, have been shown to signal through transmitter receptors and protect against acute and chronic oxidative stress, modulating the activity of different signaling pathways. Several authors have investigated the role of these nutrients in the brains of the young and the aged in degenerative diseases such as Alzheimer’s and Parkinson’s, and during brain aging due to adiposity- and physical inactivity-mediated metabolic disturbances, chronic inflammation, and oxidative stress. Through a literature review, we aimed to highlight recent data on the role of adiposity, fatty acids, antioxidants, and physical inactivity in the pathophysiology of the brain and in the molecular mechanisms of senescence. Data indicate the complexity and necessity of endogenous/dietary antioxidants for the maintenance of redox status and the control of neuroglial signaling under stress. Recent studies also indicate that omega-3 and -6 fatty acids act in a competitive manner to generate mediators for energy metabolism, influencing feeding behavior, neural plasticity, and memory during aging. Finding pharmacological or dietary resources that mitigate or prevent neurodegenerative affections continues to be a great challenge and requires additional effort from researchers, clinicians, and nutritionists in the field.
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Affiliation(s)
- Hércules Rezende Freitas
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
| | - Gustavo da Costa Ferreira
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
- Laboratory of Neuroenergetics and Inborn Errors of Metabolism, Institute of Medical Biochemistry Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
| | - Isis Hara Trevenzoli
- Laboratory of Molecular Endocrinology, Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
| | - Karen de Jesus Oliveira
- Laboratory of Endocrine Physiology and Metabology, Biomedical Institute, Universidade Federal Fluminense, Niterói 24210-130, Brazil.
| | - Ricardo Augusto de Melo Reis
- Laboratory of Neurochemistry, Institute of Biophysics Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-901, Brazil.
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10
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1,3-Dinitrobenzene neurotoxicity - Passage effect in immortalized astrocytes. Neurotoxicology 2016; 53:74-84. [PMID: 26769196 DOI: 10.1016/j.neuro.2015.11.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 11/16/2015] [Accepted: 11/18/2015] [Indexed: 11/21/2022]
Abstract
Age-related disturbances in astrocytic mitochondrial function are linked to loss of neuroprotection and decrements in neurological function. The immortalized rat neocortical astrocyte-derived cell line, DI-TNC1, provides a convenient model for the examination of cellular aging processes that are difficult to study in primary cell isolates from aged brain. Successive passages in culture may serve as a surrogate of aging in which time-dependent adaptation to culture conditions may result in altered responses to xenobiotic challenge. To investigate the hypothesis that astrocytic mitochondrial homeostatic function is decreased with time in culture, low passage DI-TNC1 astrocytes (LP; #2-8) and high passage DI-TNC1 astrocytes (HP; #17-28) were exposed to the mitochondrial neurotoxicant 1,3-dinitrobenzene (DNB). Cells were exposed in either monoculture or in co-culture with primary cortical neurons. Astrocyte mitochondrial membrane potential, morphology, ATP production and proliferation were monitored in monoculture, and the ability of DI-TNC1 cells to buffer K(+)-induced neuronal depolarization was examined in co-cultures. In HP DI-TNC1 cells, DNB exposure decreased proliferation, reduced mitochondrial membrane potential and significantly decreased mitochondrial form factor. Low passage DI-TNC1 cells effectively attenuated K(+)-induced neuronal depolarization in the presence of DNB whereas HP counterparts were unable to buffer K(+) in DNB challenge. Following DNB challenge, LP DI-TNC1 cells exhibited greater viability in co-culture than HP. The data provide compelling evidence that there is an abrupt phenotypic change in DI-TNC1 cells between passage #9-16 that significantly diminishes the ability of DI-TNC1 cells to compensate for neurotoxic challenge and provide neuroprotective spatial buffering. Whether or not these functional changes have an in vivo analog in aging brain remains to be determined.
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11
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Proft J, Weiss N. Looking for answers to L-type calcium channels in the ageing brain (Commentary on Zanoset al.). Eur J Neurosci 2015; 42:2496-8. [DOI: 10.1111/ejn.13017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Juliane Proft
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Prague Czech Republic
| | - Norbert Weiss
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Prague Czech Republic
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12
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Ron-Harel N, Sharpe AH, Haigis MC. Mitochondrial metabolism in T cell activation and senescence: a mini-review. Gerontology 2014; 61:131-8. [PMID: 25402204 DOI: 10.1159/000362502] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 03/27/2014] [Indexed: 11/19/2022] Open
Abstract
The aging immune system is unable to optimally respond to pathogens and generate long-term immunological memory against encountered antigens. Amongst the immune components most affected by aging are T lymphocytes. T lymphocytes are cells of the cell-mediated immune system, which can recognize microbial antigens and either directly kill infected cells or support the maturation and activation of other immune cells. When activated, T cells undergo a metabolic switch to accommodate their changing needs at every stage of the immune response. Here we review the different aspects of metabolic regulation of T cell activation, focusing on the emerging role of mitochondrial metabolism, and discuss changes that may contribute to age-related decline in T cell potency. Better understanding of the role of mitochondrial metabolism in immune cell function could provide insights into mechanisms of immune senescence with the potential for developing novel therapeutic approaches to improve immune responses in aged individuals.
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Affiliation(s)
- Noga Ron-Harel
- Department of Cell Biology, Harvard Medical School, Boston, Mass., USA
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13
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Proft J, Weiss N. T-type Ca(2+) channels: New players in the aging brain. Commun Integr Biol 2014; 7:e28424. [PMID: 24748914 PMCID: PMC3990594 DOI: 10.4161/cib.28424] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Accepted: 03/03/2014] [Indexed: 11/19/2022] Open
Abstract
Perhaps one of the most remarkable features of T-type calcium channels is their low-threshold of activation that makes these channels important candidates for calcium entry near the resting membrane potential of neurons. Hence, they mediate low-threshold burst discharges that occur during different forms of neuronal rhythmogenesis, but play also important roles in sensory transmission, as well as hormone and neurotransmitter release. Additionally, they have been implicated in an increasing number of neuronal pathologies including neuropathy, autism spectrum disorders and some forms of epilepsy. More recently, an implication of T-type calcium channel in the processing of Amyloid Precursor Protein was documented, with possible implication in the pathogenesis of Alzheimer’s disease.
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Affiliation(s)
- Juliane Proft
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Prague, Czech Republic
| | - Norbert Weiss
- Institute of Organic Chemistry and Biochemistry; Academy of Sciences of the Czech Republic; Prague, Czech Republic
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14
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de Souza L, Smaili SS, Ureshino RP, Sinigaglia-Coimbra R, Andersen ML, Lopes GS, Tufik S. Effect of chronic sleep restriction and aging on calcium signaling and apoptosis in the hippocampus of young and aged animals. Prog Neuropsychopharmacol Biol Psychiatry 2012; 39:23-30. [PMID: 22343009 DOI: 10.1016/j.pnpbp.2012.01.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 01/25/2012] [Accepted: 01/31/2012] [Indexed: 11/19/2022]
Abstract
Aging leads to progressive deterioration of physiological function and diminished responses to environmental stress. Organic and functional alterations are frequently observed in elderly subjects. Although chronic sleep loss is observed during senescence, little is known about the impact of insufficient sleep on cellular function in aging neurons. Disruption of neuronal calcium (Ca²⁺) signaling is related to impaired neuronal function and cell death. It has been hypothesized that sleep deprivation may compromise neuronal stability and induce cell death in young neurons; however, it is necessary to evaluate the impact of aging on this process. Therefore, the aim of this study was to evaluate the effects of chronic sleep restriction (CSR) on Ca²⁺ signaling and cell death in the hippocampus of young and aged animals. We found that glutamate and carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP) induced a greater elevation in cytosolic Ca²⁺ ([Ca²⁺](c)) in hippocampal slices from aged rats subjected to CSR compared to age-matched controls. Interestingly, aged-matched controls showed a reduced Ca²⁺ response to glutamate and FCCP, relative to both CSR and control young animals. Apoptotic nuclei were observed in aged rats from both treatment groups; however, the profile of apoptotic nuclei in aged CSR rats was highly variable. Bax and Bcl-2 protein expression did not change with aging in the CSR groups. Our study indicates that aging promotes changes in Ca²⁺ signaling, which may also be affected by CSR. These age-dependent changes in Ca²⁺ signaling may increase cellular vulnerability during CSR and contribute to Ca²⁺ signaling dysregulation, which may ultimately induce cell death.
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Affiliation(s)
- Luciane de Souza
- Departamento de Psicobiologia, Universidade Federal de São Paulo/UNIFESP, Rua Napoleão de Barros 925, Vila Clementino, 04024-002 São Paulo, SP, Brazil
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15
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Kawamoto EM, Vivar C, Camandola S. Physiology and pathology of calcium signaling in the brain. Front Pharmacol 2012; 3:61. [PMID: 22518105 PMCID: PMC3325487 DOI: 10.3389/fphar.2012.00061] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 03/26/2012] [Indexed: 12/31/2022] Open
Abstract
Calcium (Ca(2+)) plays fundamental and diversified roles in neuronal plasticity. As second messenger of many signaling pathways, Ca(2+) as been shown to regulate neuronal gene expression, energy production, membrane excitability, synaptogenesis, synaptic transmission, and other processes underlying learning and memory and cell survival. The flexibility of Ca(2+) signaling is achieved by modifying cytosolic Ca(2+) concentrations via regulated opening of plasma membrane and subcellular Ca(2+) sensitive channels. The spatiotemporal patterns of intracellular Ca(2+) signals, and the ultimate cellular biological outcome, are also dependent upon termination mechanism, such as Ca(2+) buffering, extracellular extrusion, and intra-organelle sequestration. Because of the central role played by Ca(2+) in neuronal physiology, it is not surprising that even modest impairments of Ca(2+) homeostasis result in profound functional alterations. Despite their heterogeneous etiology neurodegenerative disorders, as well as the healthy aging process, are all characterized by disruption of Ca(2+) homeostasis and signaling. In this review we provide an overview of the main types of neuronal Ca(2+) channels and their role in neuronal plasticity. We will also discuss the participation of Ca(2+) signaling in neuronal aging and degeneration.
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Affiliation(s)
- Elisa Mitiko Kawamoto
- Laboratory of Neurosciences, National Institute on Aging, Intramural Research ProgramBaltimore, MD, USA
| | - Carmen Vivar
- Laboratory of Neurosciences, National Institute on Aging, Intramural Research ProgramBaltimore, MD, USA
| | - Simonetta Camandola
- Laboratory of Neurosciences, National Institute on Aging, Intramural Research ProgramBaltimore, MD, USA
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16
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Bickler PE, Fahlman CS, Gray JJ. Hypoxic preconditioning failure in aging hippocampal neurons: Impaired gene expression and rescue with intracellular calcium chelation. J Neurosci Res 2010; 88:3520-9. [DOI: 10.1002/jnr.22508] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 06/19/2010] [Accepted: 08/12/2010] [Indexed: 12/29/2022]
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17
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Kozoriz MG, Church J, Ozog MA, Naus CC, Krebs C. Temporary sequestration of potassium by mitochondria in astrocytes. J Biol Chem 2010; 285:31107-19. [PMID: 20667836 DOI: 10.1074/jbc.m109.082073] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Increases in extracellular potassium concentration ([K(+)](o)), which can occur during neuronal activity and under pathological conditions such as ischemia, lead to a variety of potentially detrimental effects on neuronal function. Although astrocytes are known to contribute to the clearance of excess K(+)(o), the mechanisms are not fully understood. We examined the potential role of mitochondria in sequestering K(+) in astrocytes. Astrocytes were loaded with the fluorescent K(+) indicator PBFI and release of K(+) from mitochondria into the cytoplasm was examined after uncoupling the mitochondrial membrane potential with carbonyl cyanide m-chlorophenylhydrazone (CCCP). Under the experimental conditions employed, transient applications of elevated [K(+)](o) led to increases in K(+) within mitochondria, as assessed by increases in the magnitudes of cytoplasmic [K(+)] ([K(+)](i)) transients evoked by brief exposures to CCCP. When mitochondrial K(+) sequestration was impaired by prolonged application of CCCP, there was a robust increase in [K(+)](i) upon exposure to elevated [K(+)](o). Blockade of plasmalemmal K(+) uptake routes by ouabain, Ba(2+), or a mixture of voltage-activated K(+) channel inhibitors reduced K(+) uptake into mitochondria. Also, reductions in mitochondrial K(+) uptake occurred in the presence of mito-K(ATP) channel inhibitors. Rises in [K(+)](i) evoked by brief applications of CCCP following exposure to high [K(+)](o) were also reduced by gap junction blockers and in astrocytes isolated from connexin43-null mice, suggesting that connexins also play a role in K(+) uptake into astrocyte mitochondria. We conclude that mitochondria play a key role in K(+)(o) handling by astrocytes.
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Affiliation(s)
- Michael G Kozoriz
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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18
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Kumar A, Bodhinathan K, Foster TC. Susceptibility to Calcium Dysregulation during Brain Aging. Front Aging Neurosci 2009; 1:2. [PMID: 20552053 PMCID: PMC2874411 DOI: 10.3389/neuro.24.002.2009] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 10/27/2009] [Indexed: 01/06/2023] Open
Abstract
Calcium (Ca(2+)) is a highly versatile intracellular signaling molecule that is essential for regulating a variety of cellular and physiological processes ranging from fertilization to programmed cell death. Research has provided ample evidence that brain aging is associated with altered Ca(2+) homeostasis. Much of the work has focused on the hippocampus, a brain region critically involved in learning and memory, which is particularly susceptible to dysfunction during senescence. The current review takes a broader perspective, assessing age-related changes in Ca(2+) sources, Ca(2+) sequestration, and Ca(2+) binding proteins throughout the nervous system. The nature of altered Ca(2+) homeostasis is cell specific and may represent a deficit or a compensatory mechanism, producing complex patterns of impaired cellular function. Incorporating the knowledge of the complexity of age-related alterations in Ca(2+) homeostasis will positively shape the development of highly effective therapeutics to treat brain disorders.
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Affiliation(s)
- Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida Gainesville, FL, USA
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19
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Murchison D, McDermott AN, Lasarge CL, Peebles KA, Bizon JL, Griffith WH. Enhanced calcium buffering in F344 rat cholinergic basal forebrain neurons is associated with age-related cognitive impairment. J Neurophysiol 2009; 102:2194-207. [PMID: 19675291 DOI: 10.1152/jn.00301.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Alterations in neuronal Ca(2+) homeostasis are important determinants of age-related cognitive impairment. We examined the Ca(2+) influx, buffering, and electrophysiology of basal forebrain neurons in adult, middle-aged, and aged male F344 behaviorally assessed rats. Middle-aged and aged rats were characterized as cognitively impaired or unimpaired by water maze performance relative to young cohorts. Patch-clamp experiments were conducted on neurons acutely dissociated from medial septum/nucleus of the diagonal band with post hoc identification of phenotypic marker mRNA using single-cell RT-PCR. We measured whole cell calcium and barium currents and dissected these currents using pharmacological agents. We combined Ca(2+) current recording with Ca(2+)-sensitive ratiometric microfluorimetry to measure Ca(2+) buffering. Additionally, we sought changes in neuronal firing properties using current-clamp recording. There were no age- or cognition-related changes in the amplitudes or fractional compositions of the whole cell Ca(2+) channel currents. However, Ca(2+) buffering was significantly enhanced in cholinergic neurons from aged cognitively impaired rats. Moreover, increased Ca(2+) buffering was present in middle-aged rats that were not cognitively impaired. Firing properties were largely unchanged with age or cognitive status, except for an increase in the slow afterhyperpolarization in aged cholinergic neurons, independent of cognitive status. Furthermore, acutely dissociated basal forebrain neurons in which choline acetyltransferase mRNA was detected had the electrophysiological profiles of identified cholinergic neurons. We conclude that enhanced Ca(2+) buffering by cholinergic basal forebrain neurons may be important during aging.
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Affiliation(s)
- David Murchison
- 1Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College Station, Texas77843-1114, USA
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20
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Kashiyae Y, Kontani M, Kawashima H, Kiso Y, Kudo Y, Sakakibara M. Arachidonic acid enhances intracellular calcium levels in dentate gyrus, but not CA1, in aged rat. Neurosci Res 2009; 64:143-51. [DOI: 10.1016/j.neures.2009.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 02/17/2009] [Accepted: 02/19/2009] [Indexed: 01/29/2023]
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21
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Pancani T, Phelps JT, Searcy JL, Kilgore MW, Chen KC, Porter NM, Thibault O. Distinct modulation of voltage-gated and ligand-gated Ca2+ currents by PPAR-gamma agonists in cultured hippocampal neurons. J Neurochem 2009; 109:1800-11. [PMID: 19453298 DOI: 10.1111/j.1471-4159.2009.06107.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Type 2 diabetes mellitus is a metabolic disorder characterized by hyperglycemia and is especially prevalent in the elderly. Because aging is a risk factor for type 2 diabetes mellitus, and insulin resistance may contribute to the pathogenesis of Alzheimer's disease (AD), anti-diabetic agents (thiazolidinediones-TZDs) are being studied for the treatment of cognitive decline associated with AD. These agents normalize insulin sensitivity in the periphery and can improve cognition and verbal memory in AD patients. Based on evidence that Ca(2+) dysregulation is a pathogenic factor of brain aging/AD, we tested the hypothesis that TZDs could impact Ca(2+) signaling/homeostasis in neurons. We assessed the effects of pioglitazone and rosiglitazone (TZDs) on two major sources of Ca(2+) influx in primary hippocampal cultured neurons, voltage-gated Ca(2+) channel (VGCC) and the NMDA receptor (NMDAR). VGCC- and NMDAR-mediated Ca(2+) currents were recorded using patch-clamp techniques, and Ca(2+) intracellular levels were monitored with Ca(2+) imaging techniques. Rosiglitazone, but not pioglitazone reduced VGCC currents. In contrast, NMDAR-mediated currents were significantly reduced by pioglitazone but not rosiglitazone. These results show that TZDs modulate Ca(2+)-dependent pathways in the brain and have different inhibitory profiles on two major Ca(2+) sources, potentially conferring neuroprotection to an area of the brain that is particularly vulnerable to the effects of aging and/or AD.
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Affiliation(s)
- Tristano Pancani
- Department of Molecular and Biomedical Pharmacology, University of Kentucky Medical Center, 800 Rose Street, MS 310, Lexington, Kentucky 40536-0298, USA
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22
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Gleichmann M, Collis LP, Smith PJS, Mattson MP. Simultaneous single neuron recording of O2 consumption, [Ca2+]i and mitochondrial membrane potential in glutamate toxicity. J Neurochem 2009; 109:644-55. [PMID: 19226367 DOI: 10.1111/j.1471-4159.2009.05997.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In order to determine the sequence of cellular processes in glutamate toxicity, we simultaneously recorded O(2) consumption, cytosolic Ca(2+) concentration ([Ca(2+)](i)), and mitochondrial membrane potential (mDeltapsi) in single cortical neurons. Oxygen consumption was measured using an amperometric self-referencing platinum electrode adjacent to neurons in which [Ca(2+)](i) and mDeltapsi were monitored with Fluo-4 and TMRE(+), respectively, using a spinning disk laser confocal microscope. Excitotoxic doses of glutamate caused an elevation of [Ca(2+)](i) followed seconds afterwards by an increase in O(2) consumption which reached a maximum level within 1-5 min. A modest increase in mDeltapsi occurred during this time period, and then, shortly before maximal O(2) consumption was reached, the mDeltapsi, as indicated by TMRE(+) fluorescence, dissipated. Maximal O(2) consumption lasted up to 5 min and then declined together with mDeltapsi and ATP levels, while [Ca(2+)](i) further increased. mDeltapsi and [Ca(2+)](i) returned to baseline levels when neurons were treated with an NMDA receptor antagonist shortly after the [Ca(2+)](i) increased. Our unprecedented spatial and time resolution revealed that this sequence of events is identical in all neurons, albeit with considerable variability in magnitude and kinetics of changes in O(2) consumption, [Ca(2+)](i), and mDeltapsi. The data obtained using this new method are consistent with a model where Ca(2+) influx causes ATP depletion, despite maximal mitochondrial respiration, minutes after glutamate receptor activation.
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Affiliation(s)
- Marc Gleichmann
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Biomedical Research Center, Baltimore, Maryland, USA
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23
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Murchison D, Griffith WH. Calcium buffering systems and calcium signaling in aged rat basal forebrain neurons. Aging Cell 2007; 6:297-305. [PMID: 17517040 PMCID: PMC2810842 DOI: 10.1111/j.1474-9726.2007.00293.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Disturbances of neuronal Ca2+ homeostasis are considered to be important determinants of age-related cognitive impairment. Cholinergic neurons of the basal forebrain (BF) are principal targets of decline associated with aging and dementia. During the last several years, we have attempted to link these concepts in a rat model of 'normal' aging. In this review, we will describe some changes that we have observed in Ca2+ signaling of aged BF neurons and the reversal of one of these changes by dietary caloric restriction. Our evidence supports a scenario in which subtle changes in the properties of voltage-gated Ca2+ channels result in increased Ca2+ influx during aging. This increased Ca2+, in turn, triggers an increase in rapid Ca2+ buffering in the somatic compartment of aged BF neurons. However, this nominal 'compensation', along with other changes in Ca2+ handling machinery (notably mitochondria) alters the Ca2+ signal with age in a way that is dependent on the magnitude of the Ca2+ load. By combining whole-cell patch clamp electrophysiology, ratiometric Ca2+-sensitive microfluorimetry and single-cell reverse transcription-polymerase chain reaction, we have determined that age-related rapid buffering changes are present in identified cholinergic BF neurons and that these changes can be prevented by a caloric restriction dietary regimen. Because caloric restriction extends lifespan and retards the progression of age-related dysfunction, these findings suggest that increased Ca2+ buffering in cholinergic neurons may be relevant to cognitive decline during normal aging. Importantly, calcium homeostatic mechanisms of BF cholinergic neurons are amenable to dietary interventions that could promote cognitive health during aging.
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Affiliation(s)
- David Murchison
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University System Health Science Center, College Station, TX 77843-1114, USA
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24
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Toescu EC, Verkhratsky A. The importance of being subtle: small changes in calcium homeostasis control cognitive decline in normal aging. Aging Cell 2007; 6:267-73. [PMID: 17517038 DOI: 10.1111/j.1474-9726.2007.00296.x] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Aging is a complex, multifactorial process. One of the features of normal aging of the brain is a decline in cognitive functions and much experimental attention has been devoted to understanding this process. Evidence accumulated in the last decade indicates that such functional changes are not due to gross morphological alterations, but to subtle functional modification of synaptic connectivity and intracellular signalling and metabolism. Such synaptic modifications are compatible with a normal level of activity and allow the maintenance of a certain degree of functional reserve. This is in contrast to the changes in various neurodegenerative diseases, characterized by significant neuronal loss and dramatic and irreversible functional deficit. This whole special issue has been initiated with the intention of focusing on the processes of normal brain aging. In this review, we present data that shows how subtle changes in Ca(2+) homeostasis or in the state of various Ca(2+)-dependent processes or molecules, which occur in aging can have significant functional consequences.
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Affiliation(s)
- Emil C Toescu
- Department of Physiology, Division of Medical Sciences, The Medical School, University of Birmingham, Birmingham B15 2TT, UK.
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25
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Pi Y, Goldenthal MJ, Marín-García J. Mitochondrial channelopathies in aging. J Mol Med (Berl) 2007; 85:937-51. [PMID: 17426949 DOI: 10.1007/s00109-007-0190-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2006] [Revised: 01/20/2007] [Accepted: 02/16/2007] [Indexed: 12/15/2022]
Abstract
Defects in ion channels (channelopathies) are increasingly found in a large spectrum of human pathologies including aging. Mutations in genes encoding ion channel proteins, which disrupt channel function, are the most commonly identified cause of channelopathies. Mutations in associated proteins, alterations in the expression of ion channels, or changes in the activity of non-mutated channel genes or associated proteins can also produce acquired channelopathies. Mitochondria, the powerhouse of the cells, are considered to be the most important cellular organelles to contribute to aging mainly because of their role in the production of reactive oxygen species in the initiation of apoptotic cell remodeling and in efficient ATP synthesis. During the past 50 years, multiple ion channels or transporters have been found in mitochondria, and the relationship between the activity of these channels and cellular aging, as well as the overall cellular biological function, has been intensively studied in a number of cell types and animal models. In this review, we discuss the better characterized mitochondrial ion channels whose dysfunction (mitochondrial channelopathies) may affect or accelerate the aging processes. These channels include the mitochondrial ATP-sensitive potassium channel (mitoK(ATP)), Ca(2+) transporters, voltage-dependent anion channel, and the mitochondrial permeability transition pore (mitoPTP).
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Affiliation(s)
- YeQing Pi
- The Molecular Cardiology and Neuromuscular Institute, 75 Raritan Avenue, Highland Park, NJ 08904, USA
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26
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Parihar MS, Brewer GJ. Simultaneous age-related depolarization of mitochondrial membrane potential and increased mitochondrial reactive oxygen species production correlate with age-related glutamate excitotoxicity in rat hippocampal neurons. J Neurosci Res 2007; 85:1018-32. [PMID: 17335078 DOI: 10.1002/jnr.21218] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mitochondria are implicated in glutamate excitotoxicity by causing bioenergetic collapse, loss of Ca(2+) homeostasis, and generation of reactive oxygen species (ROS), all of which become increasingly important clinically with age. Little is known about how aging affects the relative importance of mitochondrial membrane potential (DeltaPsi(m)) and ROS production. To determine aging affects on DeltaPsi(m) and ROS production in individual somal and axonal/dendritic mitochondria, we compared ROS production while simultaneously monitoring DeltaPsi(m) before and after glutamate treatment of live neurons from embryonic (day 18), middle-aged (9-12 months), and old (24 months) rats. At rest, old neuronal mitochondria 1) showed a higher rate of ROS production that was particularly strong in axonal/dendritic mitochondria relative to that in middle-age neurons, 2) were more depolarized in comparison with neurons of other ages, and 3) showed no differences in ROS or DeltaPsi(m) as a function of distance from the nucleus. All DeltaPsi(m) grouped into three classes of high (less than -120 mV), medium (-85 to -120 mV), and low (greater than -85 mV) polarization that shifted toward the lower classes with age at rest. Glutamate exposure dramatically depolarized the DeltaPsi(m) in parallel with greatly increased ROS production, with a surprising absence of an effect of age or distance from the nucleus on these mitochondrial parameters. These data suggest that old neurons are more susceptible to glutamate excitotoxicity because of an insidious depolarization of DeltaPsi(m) and rate of ROS generation at rest that lead to catastrophic failure of phosphorylative and reductive energy supplies under stress.
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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, USA
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Foster KA, Margraf RR, Turner DA. NADH hyperoxidation correlates with enhanced susceptibility of aged rats to hypoxia. Neurobiol Aging 2006; 29:598-613. [PMID: 17184883 PMCID: PMC3341851 DOI: 10.1016/j.neurobiolaging.2006.11.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Revised: 11/09/2006] [Accepted: 11/13/2006] [Indexed: 11/28/2022]
Abstract
Aging increases mitochondrial dysfunction and susceptibility to hypoxia. Previous reports have indicated an association between post-hypoxic hyperoxidation of intra-mitochondrial enzymes and delayed neuronal injury. Therefore we investigated the relationship between NADH fluorescence and neuronal function during and after hypoxia across the lifespan. Hippocampal slices were prepared from adult (1 to >22 months) F344 rats. NADH fluorescence, extracellular voltage and tissue PO(2) were recorded from the CA1 region during hypoxia (95% N(2)) of various lengths following onset of hypoxic spreading depression (hsd). Slices from younger rats recovered evoked neuronal responses to a greater degree and exhibited less hyperoxidation after a hypoxic episode, than slices from older rats. However, the use of Ca(2+) free-media in slices from >22 month old rats improved recovery and delayed NADH hyperoxidation (2.5 min hypoxia after hsd). Post-hypoxic decrease of NADH fluorescence (hyperoxidation) was age dependent and correlated with decreased neuronal recovery. Slices exposed to repeated hypoxic episodes yielded data suggesting depletion of the NAD(+) pool, which may have contributed to the deterioration of neuronal function.
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Affiliation(s)
- Kelley A Foster
- Research and Surgery Services, Durham Veterans Affairs Medical Center, Durham, NC 27710, USA.
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Murphy GG, Shah V, Hell JW, Silva AJ. Investigation of age-related cognitive decline using mice as a model system: neurophysiological correlates. Am J Geriatr Psychiatry 2006; 14:1012-21. [PMID: 17138808 DOI: 10.1097/01.jgp.0000209404.54310.b3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Learning and memory impairments without overt pathology often accompany advancing age. To gain a better understanding of the underlying neuronal substrates associated with this age-related cognitive decline, the authors have begun to use mice as an animal model system. As described in the companion paper, mice exhibit age-related impairments in cognition. Here, the authors explore the possibility that age-related changes in neuronal function may be the result of deregulation of cytosolic free calcium homeostasis. METHODS Calcium homeostasis in young and aged mice was examined by measuring the slow afterhyperpolarization (sAHP) in hippocampal neurons as well as assessing voltage-dependent calcium channel mediated long-term potentiation (vdccLTP). In addition, putative changes in phosphorylation of the L-type channel Ca(V)1.2 by cAMP-dependent protein kinase were examined. RESULTS Both neurophysiological measures of calcium homeostasis indicated an increase in activity-dependent calcium influx. This increase was not the result of an age-related increase in phosphorylation of the L-type channel Ca(V)1.2 by cAMP-dependent protein kinase. CONCLUSIONS Like in other areas of biomedical research, mice have become an invaluable research tool in the investigation of learning and memory. It is expected that similar benefits can be realized by developing mouse models for age-related cognitive decline.
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Affiliation(s)
- Geoffrey G Murphy
- Department of Neurobiology, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095-1761, USA
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29
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Abstract
Mitochondria are central for various cellular processes that include ATP production, intracellular Ca(2+) signaling, and generation of reactive oxygen species. Neurons critically depend on mitochondrial function to establish membrane excitability and to execute the complex processes of neurotransmission and plasticity. While much information about mitochondrial properties is available from studies on isolated mitochondria and dissociated cell cultures, less is known about mitochondrial function in intact neurons in brain tissue. However, a detailed description of the interactions between mitochondrial function, energy metabolism, and neuronal activity is crucial for the understanding of the complex physiological behavior of neurons, as well as the pathophysiology of various neurological diseases. The combination of new fluorescence imaging techniques, electrophysiology, and brain slice preparations provides a powerful tool to study mitochondrial function during neuronal activity, with high spatiotemporal resolution. This review summarizes recent findings on mitochondrial Ca(2+) transport, mitochondrial membrane potential (DeltaPsi(m)), and energy metabolism during neuronal activity. We will first discuss interactions of these parameters for experimental stimulation conditions that can be related to the physiological range. We will then describe how mitochondrial and metabolic dysfunction develops during pathological neuronal activity, focusing on temporal lobe epilepsy and its experimental models. The aim is to illustrate that 1) the structure of the mitochondrial compartment is highly dynamic in neurons, 2) there is a fine-tuned coupling between neuronal activity and mitochondrial function, and 3) mitochondria are of central importance for the complex behavior of neurons.
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Affiliation(s)
- Oliver Kann
- Institut für Neurophysiologie, Charité-Universitätsmedizin Berlin, Tucholskystrasse 2, 10117 Berlin, Germany.
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30
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Abstract
Normal ageing is associated with a degree of decline in a number of cognitive functions. Apart from the issues raised by the current attempts to expand the lifespan, understanding the mechanisms and the detailed metabolic interactions involved in the process of normal neuronal ageing continues to be a challenge. One model, supported by a significant amount of experimental evidence, views the cellular ageing as a metabolic state characterized by an altered function of the metabolic triad: mitochondria-reactive oxygen species (ROS)-intracellular Ca2+. The perturbation in the relationship between the members of this metabolic triad generate a state of decreased homeostatic reserve, in which the aged neurons could maintain adequate function during normal activity, as demonstrated by the fact that normal ageing is not associated with widespread neuronal loss, but become increasingly vulnerable to the effects of excessive metabolic loads, usually associated with trauma, ischaemia or neurodegenerative processes. This review will concentrate on some of the evidence showing altered mitochondrial function with ageing and also discuss some of the functional consequences that would result from such events, such as alterations in mitochondrial Ca2+ homeostasis, ATP production and generation of ROS.
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Affiliation(s)
- Emil C Toescu
- Division of Medical Sciences, University of Birmingham Department of Physiology Edgbaston, Birmingham B15 2TT, UK.
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Gant JC, Sama MM, Landfield PW, Thibault O. Early and simultaneous emergence of multiple hippocampal biomarkers of aging is mediated by Ca2+-induced Ca2+ release. J Neurosci 2006; 26:3482-90. [PMID: 16571755 PMCID: PMC6673869 DOI: 10.1523/jneurosci.4171-05.2006] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Age-dependent changes in multiple Ca2+-related electrophysiological processes in the hippocampus appear to be consistent biomarkers of aging, and several also correlate with cognitive decline. These findings have led to the hypothesis that a common mechanism of Ca2+ dyshomeostasis underlies aspects of aging-dependent brain impairment. However, some key predictions of this view remain untested, including that multiple Ca2+-related biomarkers should emerge concurrently during aging and their onset should also precede/coincide with initial signs of cognitive decline. Moreover, blocking a putative common source of dysregulated Ca2+ should eliminate aging differences. Here, we tested these predictions using combined electrophysiological, imaging, and pharmacological approaches in CA1 neurons to determine the ages of onset (across 4-, 10-, 12-, 14-, and 23-month-old F344 rats) of several established biomarkers, including the increases in the slow afterhyperpolarization, spike accommodation, and [Ca2+]i rise during repetitive synaptic stimulation. In addition, we tested the hypothesis that altered Ca2+-induced Ca2+ release (CICR) from ryanodine receptors, which can be triggered by L-type Ca2+ channels, provides a common source of dysregulated Ca2+ in aging. Results showed that multiple aging biomarkers were first detectable at about the same age (12 months of age; approximately midlife), sufficiently early to influence initial cognitive decline. Furthermore, selectively blocking CICR with ryanodine slowed the Ca2+ rise during synaptic stimulation more in aged rat neurons and, notably, reduced or eliminated aging differences in the biomarkers. Thus, this study provides the first evidence that altered CICR plays a role in driving the early and simultaneous emergence in hippocampus of multiple Ca2+-related biomarkers of aging.
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del Corsso C, Ostrovskaya O, McAllister CE, Murray K, Hatton WJ, Gurney AM, Spencer NJ, Wilson SM. Effects of aging on Ca2+ signaling in murine mesenteric arterial smooth muscle cells. Mech Ageing Dev 2006; 127:315-23. [PMID: 16413046 DOI: 10.1016/j.mad.2005.12.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 11/23/2005] [Accepted: 12/07/2005] [Indexed: 11/21/2022]
Abstract
Pathophysiological changes in arterial smooth muscle structure and function occur with aging and there are a number of reports illustrating reductions in vascular responsiveness with aging. While much is known about arterial remodeling and functional adaptations with aging, very little is known about the biophysical adaptations in individual arterial myocytes. Cytosolic Ca2+ signaling, involving activation of L-type Ca2+ channels on the plasma membrane as well as InsP3 and ryanodine receptors on the sarcoplasmic reticulum, is integral to vascular tone and reactivity. Thus, we tested the hypothesis that aging results in reductions in the functional expression of L-type channels and temporal aspects of ryanodine receptor and InsP3 receptor Ca2+ signaling, in mesenteric arterial smooth muscle cells isolated from 6 and 30 months old C57Bl/6 mice. Comparisons of L-type current activity were made using dialyzed, whole-cell voltage-clamp techniques and Ba2+ as charge carrier. Ca2+ signaling was measured using fura-2 fluorescence microscopy techniques. Cell morphological changes were also investigated using electrophysiological and immunocytochemical approaches. The amplitudes of L-type Ca2+ currents were increased in older mice, but this was associated with membrane surface area increases of approximately 50%, due to increases in cell length not cell width. Consequently, L-type Ca2+ current densities were preserved with age, indicating functional channel expression was unchanged. In contrast, aging was associated with decrements in Ca2+ signaling in response to either ryanodine receptor stimulation by caffeine or InsP3 receptor activation with phenylephrine. These changes with aging may be related to the previously reported depression in myogenic reactivity.
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Affiliation(s)
- Cristiane del Corsso
- Department of Physiology, University of Nevada School of Medicine, Reno, NV 89557, USA
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Abstract
Everyone ages, but only some will develop a neurodegenerative disorder in the process. Disease might occur when cells fail to respond adaptively to age-related increases in oxidative, metabolic and ionic stress, thereby resulting in the accumulation of damaged proteins, DNA and membranes. Determinants of neuronal vulnerability might include cell size and location, metabolism of disease-specific proteins and a repertoire of signal transduction pathways and stress resistance mechanisms. Emerging evidence on protein interaction networks that monitor and respond to the normal ageing process suggests that successful neural ageing is possible for most people, but also cautions that cures for neurodegenerative disorders are unlikely in the near future.
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Affiliation(s)
- Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland 21224-6825, USA.
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Brown MR, Sullivan PG, Geddes JW. Synaptic mitochondria are more susceptible to Ca2+overload than nonsynaptic mitochondria. J Biol Chem 2006; 281:11658-68. [PMID: 16517608 DOI: 10.1074/jbc.m510303200] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Mitochondria in nerve terminals are subjected to extensive Ca2+ fluxes and high energy demands, but the extent to which the synaptic mitochondria buffer Ca2+ is unclear. In this study, we identified a difference in the Ca2+ clearance ability of nonsynaptic versus synaptic mitochondrial populations enriched from rat cerebral cortex. Mitochondria were isolated using Percoll discontinuous gradients in combination with high pressure nitrogen cell disruption. Mitochondria in the nonsynaptic fraction originate from neurons and other cell types including glia, whereas mitochondria enriched from a synaptosomal fraction are predominantly neuronal and presynaptic in origin. There were no differences in respiration or initial Ca2+ loads between nonsynaptic and synaptic mitochondrial populations. Following both bolus and infusion Ca2+ addition, nonsynaptic mitochondria were able to accumulate significantly more exogenously added Ca2+ than the synaptic mitochondria before undergoing mitochondrial permeability transition, observed as a loss in mitochondrial membrane potential and decreased Ca2+ uptake. The limited ability of synaptic mitochondria to accumulate Ca2+ could result from several factors including a primary function of ATP production to support the high energy demand of presynaptic terminals, their relative isolation in comparison with the threads or clusters of mitochondria found in the soma of neurons and glia, or the older age and increased exposure to oxidative damage of synaptic versus nonsynaptic mitochondria. By more readily undergoing permeability transition, synaptic mitochondria may initiate neuron death in response to insults that elevate synaptic levels of intracellular Ca2+, consistent with the early degeneration of distal axon segments in neurodegenerative disorders.
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Affiliation(s)
- Maile R Brown
- Graduate Center for Gerontology, Sanders-Brown Center on Aging, Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY 40536-0509, USA
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Hemond P, Jaffe DB. Caloric restriction prevents aging-associated changes in spike-mediated Ca2+ accumulation and the slow afterhyperpolarization in hippocampal CA1 pyramidal neurons. Neuroscience 2006; 135:413-20. [PMID: 16112472 DOI: 10.1016/j.neuroscience.2005.05.044] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2005] [Revised: 05/24/2005] [Accepted: 05/25/2005] [Indexed: 11/26/2022]
Abstract
In hippocampal pyramidal neurons from aged animals voltage-gated Ca2+ entry and the slow, post-burst afterhyperpolarization are enhanced. As a result, there is a decrease in neuronal excitability and, in turn, an alteration in synaptic plasticity. Restricting the caloric intake of a rodent is a well-known paradigm for increasing lifespan and ameliorating a number of neurodegenerative features of aging, including deficits in synaptic plasticity and cognition. Here we show in rat CA1 pyramidal neurons from aged animals (18-20 months old) that a restricted diet prevents the enhancement of dendritic spike-mediated Ca2+ accumulation. In contrast, no significant changes in the rates of Ca2+ recovery were observed suggesting that Ca2+ clearance mechanisms are not affected by aging or caloric restriction. Lastly, we found that caloric restriction also prevented the aging-associated increase in the slow, post-burst afterhyperpolarization. Our results suggest that caloric restriction-sensitive changes in Ca2+ accumulation and membrane excitability may in part account for the protective effects of dietary restriction on synaptic plasticity and learning deficits in aged animals.
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Affiliation(s)
- P Hemond
- Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, USA
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Lin DT, Wu J, Holstein D, Upadhyay G, Rourk W, Muller E, Lechleiter JD. Ca2+ signaling, mitochondria and sensitivity to oxidative stress in aging astrocytes. Neurobiol Aging 2005; 28:99-111. [PMID: 16359757 DOI: 10.1016/j.neurobiolaging.2005.11.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 10/31/2005] [Accepted: 11/09/2005] [Indexed: 11/30/2022]
Abstract
Age-related changes in astrocytes that could potentially affect neuroprotection have been largely unexplored. To test whether astrocyte function was diminished during the aging process, we examined cell growth, Ca2+ signaling, mitochondrial membrane potential (DeltaPsi) and neuroprotection of NGF-differentiated PC12 cells. We observed that cell growth was significantly slower for astrocytes cultured from old (26-29 months) mice as compared to young (4-6 months) mice. DeltaPsis in old astrocytes were also more depolarized (lower) than in young astrocytes and old astrocytes showed greater sensitivity to the oxidant tert-butyl hydrogen peroxide (t-BuOOH). ATP-induced Ca2+ responses in old astrocytes were consistently larger in amplitude and more frequently oscillatory than in young astrocytes, which may be attributable to lower mitochondrial Ca2+ sequestration. Finally, NGF-differentiated PC12 cells that were co-cultured with old astrocytes were significantly more sensitive to t-BuOOH treatment than co-cultures of NGF-differentiated PC12 cells with young astrocytes. Together, these data demonstrate that astrocyte physiology is significantly altered during the aging process and that the astrocyte's ability to protect neurons is compromised.
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Affiliation(s)
- Da-Ting Lin
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, United States
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