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Case SL, Lin R, Thibault O. Age- and sex-dependent alterations in primary somatosensory cortex neuronal calcium network dynamics during locomotion. Aging Cell 2023; 22:e13898. [PMID: 37269157 PMCID: PMC10410056 DOI: 10.1111/acel.13898] [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: 03/16/2023] [Revised: 05/12/2023] [Accepted: 05/22/2023] [Indexed: 06/04/2023] Open
Abstract
Over the past 30 years, the calcium (Ca2+ ) hypothesis of brain aging has provided clear evidence that hippocampal neuronal Ca2+ dysregulation is a key biomarker of aging. Age-dependent Ca2+ -mediated changes in intrinsic excitability, synaptic plasticity, and activity have helped identify some of the mechanisms engaged in memory and cognitive decline based on work done mostly at the single-cell level and in the slice preparation. Recently, our lab identified age- and Ca2+ -related neuronal network dysregulation in the cortex of the anesthetized animal. Still, investigations in the awake animal are needed to test the generalizability of the Ca2+ hypothesis of brain aging. Here, we used in vigilo two-photon imaging in ambulating mice, to image GCaMP8f in the primary somatosensory cortex (S1), during ambulation and at rest. We investigated aging- and sex-related changes in neuronal networks in the C56BL/6J mouse. Following imaging, gait behavior was characterized to test for changes in locomotor stability. During ambulation, in both young adult and aged mice, an increase in network connectivity and synchronicity was noted. An age-dependent increase in synchronicity was seen in ambulating aged males only. Additionally, females displayed increases in the number of active neurons, Ca2+ transients, and neuronal activity compared to males, particularly during ambulation. These results suggest S1 Ca2+ dynamics and network synchronicity are likely contributors of locomotor stability. We believe this work raises awareness of age- and sex-dependent alterations in S1 neuronal networks, perhaps underlying the increase in falls with age.
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Affiliation(s)
- Sami L. Case
- Department of Pharmacology & Nutritional SciencesUniversity of Kentucky College of MedicineLexingtonKentuckyUSA
| | - Ruei‐Lung Lin
- Department of Pharmacology & Nutritional SciencesUniversity of Kentucky College of MedicineLexingtonKentuckyUSA
| | - Olivier Thibault
- Department of Pharmacology & Nutritional SciencesUniversity of Kentucky College of MedicineLexingtonKentuckyUSA
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2
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Caulfield ME, Vander Werp MJ, Stancati JA, Collier TJ, Sortwell CE, Sandoval IM, Manfredsson FP, Steece-Collier K. Downregulation of striatal CaV1.3 inhibits the escalation of levodopa-induced dyskinesia in male and female parkinsonian rats of advanced age. Neurobiol Dis 2023; 181:106111. [PMID: 37001610 DOI: 10.1016/j.nbd.2023.106111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/17/2023] [Accepted: 03/28/2023] [Indexed: 03/31/2023] Open
Abstract
In the past 25 years, the prevalence of Parkinson's disease (PD) has nearly doubled. Age remains the primary risk factor for PD and as the global aging population increases this trend is predicted to continue. Even when treated with levodopa, the gold standard dopamine (DA) replacement therapy, individuals with PD frequently develop therapeutic side effects. Levodopa-induced dyskinesia (LID), a common side effect of long-term levodopa use, represents a significant unmet clinical need in the treatment of PD. Previously, in young adult (3-month-old) male parkinsonian rats, we demonstrated that the silencing of CaV1.3 (Cacan1d) L-type voltage-gated calcium channels via striatal delivery of rAAV-CaV1.3-shRNA provides uniform protection against the induction of LID, and significant reduction of established severe LID. With the goal of more closely replicating a clinical demographic, the current study examined the effects of CaV1.3-targeted gene therapy on LID escalation in male and female parkinsonian rats of advanced age (18-month-old at study completion). We tested the hypothesis that silencing aberrant CaV1.3 channel activity in the parkinsonian striatum would prevent moderate to severe dyskinesia with levodopa dose escalation. To test this hypothesis, 15-month-old male and female F344 rats were rendered unilaterally parkinsonian and primed with low-dose (3-4 mg/kg) levodopa. Following the establishment of stable, mild dyskinesias, rats received an intrastriatal injection of either the Cacna1d-specific rAAV-CaV1.3-shRNA vector (CAV-shRNA), or the scramble control rAAV-SCR-shRNA vector (SCR-shRNA). Daily (M-Fr) low-dose levodopa was maintained for 4 weeks during the vector transduction and gene silencing window followed by escalation to 6 mg/kg, then to 12 mg/kg levodopa. SCR-shRNA-shRNA rats showed stable LID expression with low-dose levodopa and the predicted escalation of LID severity with increased levodopa doses. Conversely, complex behavioral responses were observed in aged rats receiving CAV-shRNA, with approximately half of the male and female subjects-therapeutic 'Responders'-demonstrating protection against LID escalation, while the remaining half-therapeutic 'Non-Responders'-showed LID escalation similar to SCR-shRNA rats. Post-mortem histological analyses revealed individual variability in the detection of Cacna1d regulation in the DA-depleted striatum of aged rats. However, taken together, male and female therapeutic 'Responder' rats receiving CAV-shRNA had significantly less striatal Cacna1d in their vector-injected striatum relative to contralateral striatum than those with SCR-shRNA. The current data suggest that mRNA-level silencing of striatal CaV1.3 channels maintains potency in a clinically relevant in vivo scenario by preventing dose-dependent dyskinesia escalation in rats of advanced age. As compared to the uniform response previously reported in young male rats, there was notable variability between individual aged rats, particularly females, in the current study. Future investigations are needed to derive the sex-specific and age-related mechanisms which underlie variable responses to gene therapy and to elucidate factors which determine the therapeutic efficacy of treatment for PD.
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Maziar A, Critch TNRHY, Ghosh S, Rajani V, Flynn CM, Qin T, Reinhardt C, Man KNM, Lee A, Hell JW, Yuan Q. Aging differentially affects LTCC function in hippocampal CA1 and piriform cortex pyramidal neurons. Cereb Cortex 2023; 33:1489-1503. [PMID: 35437602 PMCID: PMC9930631 DOI: 10.1093/cercor/bhac152] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/25/2022] [Accepted: 03/27/2022] [Indexed: 11/14/2022] Open
Abstract
Aging is associated with cognitive decline and memory loss in humans. In rats, aging-associated neuronal excitability changes and impairments in learning have been extensively studied in the hippocampus. Here, we investigated the roles of L-type calcium channels (LTCCs) in the rat piriform cortex (PC), in comparison with those of the hippocampus. We employed spatial and olfactory tasks that involve the hippocampus and PC. LTCC blocker nimodipine administration impaired spontaneous location recognition in adult rats (6-9 months). However, the same blocker rescued the spatial learning deficiency in aged rats (19-23 months). In an odor-associative learning task, infusions of nimodipine into either the PC or dorsal CA1 impaired the ability of adult rats to learn a positive odor association. Again, in contrast, nimodipine rescued odor associative learning in aged rats. Aged CA1 neurons had higher somatic expression of LTCC Cav1.2 subunits, exhibited larger afterhyperpolarization (AHP) and lower excitability compared with adult neurons. In contrast, PC neurons from aged rats showed higher excitability and no difference in AHP. Cav1.2 expression was similar in adult and aged PC somata, but relatively higher in PSD95- puncta in aged dendrites. Our data suggest unique features of aging-associated changes in LTCCs in the PC and hippocampus.
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Affiliation(s)
- Aida Maziar
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL A1B 3V6, Canada
| | - Tristian N R H Y Critch
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL A1B 3V6, Canada
| | - Sourav Ghosh
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL A1B 3V6, Canada
| | - Vishaal Rajani
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL A1B 3V6, Canada
| | - Cassandra M Flynn
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL A1B 3V6, Canada
| | - Tian Qin
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL A1B 3V6, Canada
| | - Camila Reinhardt
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL A1B 3V6, Canada
| | - Kwun Nok Mimi Man
- Department of Pharmacology, School of Medicine, University of California-Davis, Sacramento, CA 95817, United States
| | - Amy Lee
- Department of Neuroscience, University of Texas-Austin, Austin, TX 78712, United States
| | - Johannes W Hell
- Department of Pharmacology, School of Medicine, University of California-Davis, Sacramento, CA 95817, United States
| | - Qi Yuan
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, NL A1B 3V6, Canada
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Modulation of L-type calcium channels in Alzheimer's disease: A potential therapeutic target. Comput Struct Biotechnol J 2022; 21:11-20. [PMID: 36514335 PMCID: PMC9719069 DOI: 10.1016/j.csbj.2022.11.049] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 11/28/2022] Open
Abstract
Calcium plays a fundamental role in various signaling pathways and cellular processes in the human organism. In the nervous system, voltage-gated calcium channels such as L-type calcium channels (LTCCs) are critical elements in mediating neurotransmitter release, synaptic integration and plasticity. Dysfunction of LTCCs has been implicated in both aging and Alzheimer's Disease (AD), constituting a key component of calcium hypothesis of AD. As such, LTCCs are a promising drug target in AD. However, due to their structural and functional complexity, the mechanisms by which LTCCs contribute to AD are still unclear. In this review, we briefly summarize the structure, function, and modulation of LTCCs that are the backbone for understanding pathological processes involving LTCCs. We suggest targeting molecular pathways up-regulating LTCCs in AD may be a more promising approach, given the diverse physiological functions of LTCCs and the ineffectiveness of LTCC blockers in clinical studies.
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Key Words
- AC, adenylyl cyclase
- AD, Alzheimer’s Disease
- AHP, afterhyperpolarization
- AR, adrenoceptor
- Aging
- Alzheimer’s disease
- Aβ, β-amyloid
- BIN1, bridging integrator 1
- BTZs, benzothiazepines
- CDF, calcium-dependent facilitation
- CDI, calcium-dependent inactivation
- CaMKII, calmodulin-dependent protein kinase II
- DHP, dihydropyridine
- L-type calcium channel
- LTCC, L-type calcium channels
- LTD, long-term depression
- LTP, long-term potentiation
- NFT, neurofibrillary tangles
- NMDAR, N-methyl-D-aspartate receptor
- PAA, phenylalkylamines
- PKA, protein kinase A
- PKC, protein kinase C
- PKG, protein kinase G
- SFK, Src family kinase
- Tau
- VSD, voltage sensing domain
- β-Amyloid
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5
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Tau isoform-specific enhancement of L-type calcium current and augmentation of afterhyperpolarization in rat hippocampal neurons. Sci Rep 2022; 12:15231. [PMID: 36075936 PMCID: PMC9458744 DOI: 10.1038/s41598-022-18648-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 08/17/2022] [Indexed: 11/08/2022] Open
Abstract
Accumulation of tau is observed in dementia, with human tau displaying 6 isoforms grouped by whether they display either 3 or 4 C-terminal repeat domains (3R or 4R) and exhibit no (0N), one (1N) or two (2N) N terminal repeats. Overexpression of 4R0N-tau in rat hippocampal slices enhanced the L-type calcium (Ca2+) current-dependent components of the medium and slow afterhyperpolarizations (AHPs). Overexpression of both 4R0N-tau and 4R2N-tau augmented CaV1.2-mediated L-type currents when expressed in tsA-201 cells, an effect not observed with the third 4R isoform, 4R1N-tau. Current enhancement was only observed when the pore-forming subunit was co-expressed with CaVβ3 and not CaVβ2a subunits. Non-stationary noise analysis indicated that enhanced Ca2+ channel current arose from a larger number of functional channels. 4R0N-tau and CaVβ3 were found to be physically associated by co-immunoprecipitation. In contrast, the 4R1N-tau isoform that did not augment expressed macroscopic L-type Ca2+ current exhibited greatly reduced binding to CaVβ3. These data suggest that physical association between tau and the CaVβ3 subunit stabilises functional L-type channels in the membrane, increasing channel number and Ca2+ influx. Enhancing the Ca2+-dependent component of AHPs would produce cognitive impairment that underlie those seen in the early phases of tauopathies.
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6
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Huffels CFM, van Dijk RE, Karst H, Meye FJ, Hol EM, Middeldorp J. Systemic Injection of Aged Blood Plasma in Adult C57BL/6 Mice Induces Neurophysiological Impairments in the Hippocampal CA1. J Alzheimers Dis 2022; 89:283-297. [PMID: 35871343 DOI: 10.3233/jad-220337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Aging is characterized by systemic alterations and forms an important risk factor for Alzheimer's disease. Recently, it has been indicated that blood-borne factors present in the systemic milieu contribute to the aging process. Exposing young mice to aged blood plasma results in impaired neurogenesis and synaptic plasticity in the dentate gyrus, as well as impaired cognition. Vice versa, treating aged mice with young blood plasma rescues impairments associated with aging. OBJECTIVE Whether blood-borne factors are sufficient to drive impairments outside the dentate gyrus, how they impact neurophysiology, and how the functional outcome compares to impairments found in mouse models for AD is still unclear. METHODS Here, we treated adult mice with blood plasma from aged mice and assessed neurophysiological parameters in the hippocampal CA1. RESULTS Mice treated with aged blood plasma show significantly impaired levels of long-term potentiation (LTP), similar to those present in APP/PS1 mice. These impaired levels of LTP in plasma-treated mice are associated with alterations in basic properties of glutamatergic transmission and the enhanced activity of voltage-gated Ca2 + channels. CONCLUSION Together, the data presented in this study show that blood-borne factors are sufficient to drive neurophysiological impairments in the hippocampal CA1.
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Affiliation(s)
- Christiaan F M Huffels
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Roland E van Dijk
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Henk Karst
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Frank J Meye
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Jinte Middeldorp
- Department of Translational Neuroscience, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands.,Department of Neurobiology & Aging, Biomedical Primate Research Centre, Rijswijk, The Netherlands
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7
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Li Y, Yang H, He T, Zhang L, Liu C. Post-Translational Modification of Cav1.2 and its Role in Neurodegenerative Diseases. Front Pharmacol 2022; 12:775087. [PMID: 35111050 PMCID: PMC8802068 DOI: 10.3389/fphar.2021.775087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/08/2021] [Indexed: 11/26/2022] Open
Abstract
Cav1.2 plays an essential role in learning and memory, drug addiction, and neuronal development. Intracellular calcium homeostasis is disrupted in neurodegenerative diseases because of abnormal Cav1.2 channel activity and modification of downstream Ca2+ signaling pathways. Multiple post-translational modifications of Cav1.2 have been observed and seem to be closely related to the pathogenesis of neurodegenerative diseases. The specific molecular mechanisms by which Cav1.2 channel activity is regulated remain incompletely understood. Dihydropyridines (DHPs), which are commonly used for hypertension and myocardial ischemia, have been repurposed to treat PD and AD and show protective effects. However, further studies are needed to improve delivery strategies and drug selectivity. Better knowledge of channel modulation and more specific methods for altering Cav1.2 channel function may lead to better therapeutic strategies for neurodegenerative diseases.
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Affiliation(s)
- Yun Li
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Hong Yang
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Tianhan He
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Liang Zhang
- Department of Neurology, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Chao Liu
- Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, School of Anesthesiology, Xuzhou Medical University, Xuzhou, China
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Age-Dependent Contributions of NMDA Receptors and L-Type Calcium Channels to Long-Term Depression in the Piriform Cortex. Int J Mol Sci 2021; 22:ijms222413551. [PMID: 34948347 PMCID: PMC8706958 DOI: 10.3390/ijms222413551] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 11/17/2022] Open
Abstract
In the hippocampus, the contributions of N-methyl-D-aspartate receptors (NMDARs) and L-type calcium channels (LTCCs) to neuronal transmission and synaptic plasticity change with aging, underlying calcium dysregulation and cognitive dysfunction. However, the relative contributions of NMDARs and LTCCs in other learning encoding structures during aging are not known. The piriform cortex (PC) plays a significant role in odor associative memories, and like the hippocampus, exhibits forms of long-term synaptic plasticity. Here, we investigated the expression and contribution of NMDARs and LTCCs in long-term depression (LTD) of the PC associational fiber pathway in three cohorts of Sprague Dawley rats: neonatal (1-2 weeks), young adult (2-3 months) and aged (20-25 months). Using a combination of slice electrophysiology, Western blotting, fluorescent immunohistochemistry and confocal imaging, we observed a shift from an NMDAR to LTCC mediation of LTD in aged rats, despite no difference in the amount of LTD expression. These changes in plasticity are related to age-dependent differential receptor expression in the PC. LTCC Cav1.2 expression relative to postsynaptic density protein 95 is increased in the associational pathway of the aged PC layer Ib. Enhanced LTCC contribution in synaptic depression in the PC may contribute to altered olfactory function and learning with aging.
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9
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Meyer C, Kettner A, Hochenegg U, Rubi L, Hilber K, Koenig X, Boehm S, Hotka M, Kubista H. On the Origin of Paroxysmal Depolarization Shifts: The Contribution of Ca v1.x Channels as the Common Denominator of a Polymorphous Neuronal Discharge Pattern. Neuroscience 2021; 468:265-281. [PMID: 34015369 DOI: 10.1016/j.neuroscience.2021.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 04/29/2021] [Accepted: 05/08/2021] [Indexed: 11/15/2022]
Abstract
Since their discovery in the 1960s, the term paroxysmal depolarization shift (PDS) has been applied to a wide variety of reinforced neuronal discharge patterns. Occurrence of PDS as cellular correlates of electrographic spikes during latent phases of insult-induced rodent epilepsy models and their resemblance to giant depolarizing potentials (GDPs) nourished the idea that PDS may be involved in epileptogenesis. Both GDPs and - in analogy - PDS may lead to progressive changes of neuronal properties by generation of pulsatile intracellular Ca2+ elevations. Herein, a key element is the gating of L-type voltage gated Ca2+ channels (LTCCs, Cav1.x family), which may convey Ca2+ signals to the nucleus. Accordingly, the present study investigates various insult-associated neuronal challenges for their propensities to trigger PDS in a LTCC-dependent manner. Our data demonstrate that diverse disturbances of neuronal function are variably suited to induce PDS-like events, and the contribution of LTCCs is essential to evoke PDS in rat hippocampal neurons that closely resemble GDPs. These PDS appear to be initiated in the dendritic sub-compartment. Their morphology critically depends on the position of recording electrodes and on their rate of occurrence. These results provide novel insight into induction mechanisms, origin, variability, and co-existence of PDS with other discharge patterns and thereby pave the way for future investigations regarding the role of PDS in epileptogenesis.
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Affiliation(s)
- Christiane Meyer
- Center of Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria.
| | - Annika Kettner
- University of Applied Sciences (FH Campus Wien), Favoritenstrasse 226, 1100 Vienna, Austria.
| | - Ulla Hochenegg
- Center of Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Lena Rubi
- Center of Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria.
| | - Karlheinz Hilber
- Center of Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria.
| | - Xaver Koenig
- Center of Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria.
| | - Stefan Boehm
- Center of Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria.
| | - Matej Hotka
- Center of Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria.
| | - Helmut Kubista
- Center of Physiology and Pharmacology, Department of Neurophysiology and -pharmacology, Medical University of Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria.
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10
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The aging mouse brain: cognition, connectivity and calcium. Cell Calcium 2021; 94:102358. [PMID: 33517250 DOI: 10.1016/j.ceca.2021.102358] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/16/2021] [Accepted: 01/18/2021] [Indexed: 02/08/2023]
Abstract
Aging is a complex process that differentially impacts multiple cognitive, sensory, neuronal and molecular processes. Technological innovations now allow for parallel investigation of neuronal circuit function, structure and molecular composition in the brain of awake behaving adult mice. Thus, mice have become a critical tool to better understand how aging impacts the brain. However, a more granular systems-based approach, which considers the impact of age on key features relating to neural processing, is required. Here, we review evidence probing the impact of age on the mouse brain. We focus on a range of processes relating to neuronal function, including cognitive abilities, sensory systems, synaptic plasticity and calcium regulation. Across many systems, we find evidence for prominent age-related dysregulation even before 12 months of age, suggesting that emerging age-related alterations can manifest by late adulthood. However, we also find reports suggesting that some processes are remarkably resilient to aging. The evidence suggests that aging does not drive a parallel, linear dysregulation of all systems, but instead impacts some processes earlier, and more severely, than others. We propose that capturing the more fine-scale emerging features of age-related vulnerability and resilience may provide better opportunities for the rejuvenation of the aged brain.
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11
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Pousinha PA, Mouska X, Bianchi D, Temido-Ferreira M, Rajão-Saraiva J, Gomes R, Fernandez SP, Salgueiro-Pereira AR, Gandin C, Raymond EF, Barik J, Goutagny R, Bethus I, Lopes LV, Migliore M, Marie H. The Amyloid Precursor Protein C-Terminal Domain Alters CA1 Neuron Firing, Modifying Hippocampus Oscillations and Impairing Spatial Memory Encoding. Cell Rep 2020; 29:317-331.e5. [PMID: 31597094 DOI: 10.1016/j.celrep.2019.08.103] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 08/09/2019] [Accepted: 08/29/2019] [Indexed: 12/15/2022] Open
Abstract
There is a growing consensus that Alzheimer's disease (AD) involves failure of the homeostatic machinery, which underlies the firing stability of neural circuits. What are the culprits leading to neuron firing instability? The amyloid precursor protein (APP) is central to AD pathogenesis, and we recently showed that its intracellular domain (AICD) could modify synaptic signal integration. We now hypothesize that AICD modifies neuron firing activity, thus contributing to the disruption of memory processes. Using cellular, electrophysiological, and behavioral techniques, we show that pathological AICD levels weaken CA1 neuron firing activity through a gene-transcription-dependent mechanism. Furthermore, increased AICD production in hippocampal neurons modifies oscillatory activity, specifically in the γ-frequency range, and disrupts spatial memory task. Collectively, our data suggest that AICD pathological levels, observed in AD mouse models and in human patients, might contribute to progressive neuron homeostatic failure, driving the shift from normal aging to AD.
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Affiliation(s)
| | - Xavier Mouska
- Université Côte d'Azur, CNRS UMR 7275, IPMC, Valbonne, France
| | - Daniela Bianchi
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Mariana Temido-Ferreira
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Lisboa, Portugal
| | - Joana Rajão-Saraiva
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Lisboa, Portugal
| | - Rui Gomes
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Lisboa, Portugal
| | | | | | - Carine Gandin
- Université Côte d'Azur, CNRS UMR 7275, IPMC, Valbonne, France
| | | | - Jacques Barik
- Université Côte d'Azur, CNRS UMR 7275, IPMC, Valbonne, France
| | - Romain Goutagny
- Université de Strasbourg, CNRS UMR 7364, LNCA, Strasbourg, France
| | - Ingrid Bethus
- Université Côte d'Azur, CNRS UMR 7275, IPMC, Valbonne, France
| | - Luisa V Lopes
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Lisboa, Portugal
| | - Michele Migliore
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Hélène Marie
- Université Côte d'Azur, CNRS UMR 7275, IPMC, Valbonne, France
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Aging Alters Olfactory Bulb Network Oscillations and Connectivity: Relevance for Aging-Related Neurodegeneration Studies. Neural Plast 2020; 2020:1703969. [PMID: 32774353 PMCID: PMC7396091 DOI: 10.1155/2020/1703969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/27/2020] [Accepted: 02/12/2020] [Indexed: 11/18/2022] Open
Abstract
The aging process eventually cause a breakdown in critical synaptic plasticity and connectivity leading to deficits in memory function. The olfactory bulb (OB) and the hippocampus, both regions of the brain considered critical for the processing of odors and spatial memory, are commonly affected by aging. Using an aged wild-type C57B/6 mouse model, we sought to define the effects of aging on hippocampal plasticity and the integrity of cortical circuits. Specifically, we measured the long-term potentiation of high-frequency stimulation (HFS-LTP) at the Shaffer-Collateral CA1 pyramidal synapses. Next, local field potential (LFP) spectra, phase-amplitude theta-gamma coupling (PAC), and connectivity through coherence were assessed in the olfactory bulb, frontal and entorhinal cortices, CA1, and amygdala circuits. The OB of aged mice showed a significant increase in the number of histone H2AX-positive neurons, a marker of DNA damage. While the input-output relationship measure of basal synaptic activity was found not to differ between young and aged mice, a pronounced decline in the slope of field excitatory postsynaptic potential (fEPSP) and the population spike amplitude (PSA) were found in aged mice. Furthermore, aging was accompanied by deficits in gamma network oscillations, a shift to slow oscillations, reduced coherence and theta-gamma PAC in the OB circuit. Thus, while the basal synaptic activity was unaltered in older mice, impairment in hippocampal synaptic transmission was observed only in response to HFS. However, age-dependent alterations in neural network appeared spontaneously in the OB circuit, suggesting the neurophysiological basis of synaptic deficits underlying olfactory processing. Taken together, the results highlight the sensitivity and therefore potential use of LFP quantitative network oscillations and connectivity at the OB level as objective electrophysiological markers that will help reveal specific dysfunctional circuits in aging-related neurodegeneration studies.
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Presynaptic L-Type Ca 2+ Channels Increase Glutamate Release Probability and Excitatory Strength in the Hippocampus during Chronic Neuroinflammation. J Neurosci 2020; 40:6825-6841. [PMID: 32747440 DOI: 10.1523/jneurosci.2981-19.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 06/18/2020] [Accepted: 07/20/2020] [Indexed: 12/21/2022] Open
Abstract
Neuroinflammation is involved in the pathogenesis of several neurologic disorders, including epilepsy. Both changes in the input/output functions of synaptic circuits and cell Ca2+ dysregulation participate in neuroinflammation, but their impact on neuron function in epilepsy is still poorly understood. Lipopolysaccharide (LPS), a toxic byproduct of bacterial lysis, has been extensively used to stimulate inflammatory responses both in vivo and in vitro LPS stimulates Toll-like receptor 4, an important mediator of the brain innate immune response that contributes to neuroinflammation processes. Although we report that Toll-like receptor 4 is expressed in both excitatory and inhibitory mouse hippocampal neurons (both sexes), its chronic stimulation by LPS induces a selective increase in the excitatory synaptic strength, characterized by enhanced synchronous and asynchronous glutamate release mechanisms. This effect is accompanied by a change in short-term plasticity with decreased facilitation, decreased post-tetanic potentiation, and increased depression. Quantal analysis demonstrated that the effects of LPS on excitatory transmission are attributable to an increase in the probability of release associated with an overall increased expression of L-type voltage-gated Ca2+ channels that, at presynaptic terminals, abnormally contributes to evoked glutamate release. Overall, these changes contribute to the excitatory/inhibitory imbalance that scales up neuronal network activity under inflammatory conditions. These results provide new molecular clues for treating hyperexcitability of hippocampal circuits associated with neuroinflammation in epilepsy and other neurologic disorders.SIGNIFICANCE STATEMENT Neuroinflammation is thought to have a pathogenetic role in epilepsy, a disorder characterized by an imbalance between excitation/inhibition. Fine adjustment of network excitability and regulation of synaptic strength are both implicated in the homeostatic maintenance of physiological levels of neuronal activity. Here, we focused on the effects of chronic neuroinflammation induced by lipopolysaccharides on hippocampal glutamatergic and GABAergic synaptic transmission. Our results show that, on chronic stimulation with lipopolysaccharides, glutamatergic, but not GABAergic, neurons exhibit an enhanced synaptic strength and changes in short-term plasticity because of an increased glutamate release that results from an anomalous contribution of L-type Ca2+ channels to neurotransmitter release.
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14
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Wang S, Cortes CJ. Interactions with PDZ proteins diversify voltage-gated calcium channel signaling. J Neurosci Res 2020; 99:332-348. [PMID: 32476168 DOI: 10.1002/jnr.24650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 04/29/2020] [Accepted: 05/07/2020] [Indexed: 11/12/2022]
Abstract
Voltage-gated Ca2+ (CaV ) channels are crucial for neuronal excitability and synaptic transmission upon depolarization. Their properties in vivo are modulated by their interaction with a variety of scaffolding proteins. Such interactions can influence the function and localization of CaV channels, as well as their coupling to intracellular second messengers and regulatory pathways, thus amplifying their signaling potential. Among these scaffolding proteins, a subset of PDZ (postsynaptic density-95, Drosophila discs-large, and zona occludens)-domain containing proteins play diverse roles in modulating CaV channel properties. At the presynaptic terminal, PDZ proteins enrich CaV channels in the active zone, enabling neurotransmitter release by maintaining a tight and vital link between channels and vesicles. In the postsynaptic density, these interactions are essential in regulating dendritic spine morphology and postsynaptic signaling cascades. In this review, we highlight the studies that demonstrate dynamic regulations of neuronal CaV channels by PDZ proteins. We discuss the role of PDZ proteins in controlling channel activity, regulating channel cell surface density, and influencing channel-mediated downstream signaling events. We highlight the importance of PDZ protein regulations of CaV channels and evaluate the link between this regulatory effect and human disease.
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Affiliation(s)
- Shiyi Wang
- Department of Cell Biology, Duke University, Durham, NC, USA.,Department of Neurology, Duke University, Durham, NC, USA
| | - Constanza J Cortes
- Department of Neurology, Duke University, Durham, NC, USA.,Department of Cell, Developmental and Integrative Biology, University of Alabama Birmingham, Birmingham, AL, USA
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15
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Moore SJ, Murphy GG. The role of L-type calcium channels in neuronal excitability and aging. Neurobiol Learn Mem 2020; 173:107230. [PMID: 32407963 DOI: 10.1016/j.nlm.2020.107230] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/09/2020] [Accepted: 04/12/2020] [Indexed: 12/11/2022]
Abstract
Over the last two decades there has been significant progress towards understanding the neural substrates that underlie age-related cognitive decline. Although many of the exact molecular and cellular mechanisms have yet to be fully understood, there is consensus that alterations in neuronal calcium homeostasis contribute to age-related deficits in learning and memory. Furthermore, it is thought that the age-related changes in calcium homeostasis are driven, at least in part, by changes in calcium channel expression. In this review, we focus on the role of a specific class of calcium channels: L-type voltage-gated calcium channels (LVGCCs). We provide the reader with a general introduction to voltage-gated calcium channels, followed by a more detailed description of LVGCCs and how they serve to regulate neuronal excitability via the post burst afterhyperpolarization (AHP). We conclude by reviewing studies that link the slow component of the AHP to learning and memory, and discuss how age-related increases in LVGCC expression may underlie cognitive decline by mediating a decrease in neuronal excitability.
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Affiliation(s)
- Shannon J Moore
- Michigan Neuroscience Institute, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109, United States; Department of Molecular and Integrative Physiology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109, United States
| | - Geoffrey G Murphy
- Michigan Neuroscience Institute, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109, United States; Department of Molecular and Integrative Physiology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109, United States.
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16
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Hopp SC. Targeting microglia L-type voltage-dependent calcium channels for the treatment of central nervous system disorders. J Neurosci Res 2020; 99:141-162. [PMID: 31997405 DOI: 10.1002/jnr.24585] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/03/2020] [Accepted: 01/08/2020] [Indexed: 12/14/2022]
Abstract
Calcium (Ca2+ ) is a ubiquitous mediator of a multitude of cellular functions in the central nervous system (CNS). Intracellular Ca2+ is tightly regulated by cells, including entry via plasma membrane Ca2+ permeable channels. Of specific interest for this review are L-type voltage-dependent Ca2+ channels (L-VDCCs), due to their pleiotropic role in several CNS disorders. Currently, there are numerous approved drugs that target L-VDCCs, including dihydropyridines. These drugs are safe and effective for the treatment of humans with cardiovascular disease and may also confer neuroprotection. Here, we review the potential of L-VDCCs as a target for the treatment of CNS disorders with a focus on microglia L-VDCCs. Microglia, the resident immune cells of the brain, have attracted recent attention for their emerging inflammatory role in several CNS diseases. Intracellular Ca2+ regulates microglia transition from a resting quiescent state to an "activated" immune-effector state and is thus a valuable target for manipulation of microglia phenotype. We will review the literature on L-VDCC expression and function in the CNS and on microglia in vitro and in vivo and explore the therapeutic landscape of L-VDCC-targeting agents at present and future challenges in the context of Alzheimer's disease, Parkinson's disease, Huntington's disease, neuropsychiatric diseases, and other CNS disorders.
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Affiliation(s)
- Sarah C Hopp
- Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health Science Center San Antonio, San Antonio, TX, USA.,Department of Pharmacology, University of Texas Health Science Center San Antonio, San Antonio, TX, USA
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17
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Kumar A. Calcium Signaling During Brain Aging and Its Influence on the Hippocampal Synaptic Plasticity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:985-1012. [PMID: 31646542 DOI: 10.1007/978-3-030-12457-1_39] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Calcium (Ca2+) ions are highly versatile intracellular signaling molecules and are universal second messenger for regulating a variety of cellular and physiological functions including synaptic plasticity. Ca2+ homeostasis in the central nervous system endures subtle dysregulation with advancing age. Research has provided abundant evidence that brain aging is associated with altered neuronal Ca2+ regulation and synaptic plasticity mechanisms. 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 aging. The current chapter takes a specific perspective, assessing various Ca2+ sources and the influence of aging on Ca2+ sources and synaptic plasticity in the hippocampus. Integrating the knowledge of the complexity of age-related alterations in neuronal Ca2+ signaling and synaptic plasticity mechanisms will positively shape the development of highly effective therapeutics to treat brain disorders including cognitive impairment associated with aging and neurodegenerative disease.
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Affiliation(s)
- Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
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18
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Calcium Signaling in Neurons and Glial Cells: Role of Cav1 channels. Neuroscience 2019; 421:95-111. [DOI: 10.1016/j.neuroscience.2019.09.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 09/27/2019] [Accepted: 09/30/2019] [Indexed: 11/18/2022]
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19
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Man KNM, Navedo MF, Horne MC, Hell JW. β 2 Adrenergic Receptor Complexes with the L-Type Ca 2+ Channel Ca V1.2 and AMPA-Type Glutamate Receptors: Paradigms for Pharmacological Targeting of Protein Interactions. Annu Rev Pharmacol Toxicol 2019; 60:155-174. [PMID: 31561738 DOI: 10.1146/annurev-pharmtox-010919-023404] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Formation of signaling complexes is crucial for the orchestration of fast, efficient, and specific signal transduction. Pharmacological disruption of defined signaling complexes has the potential for specific intervention in selected regulatory pathways without affecting organism-wide disruption of parallel pathways. Signaling by epinephrine and norepinephrine through α and β adrenergic receptors acts on many signaling pathways in many cell types. Here, we initially provide an overview of the signaling complexes formed between the paradigmatic β2 adrenergic receptor and two of its most important targets, the L-type Ca2+ channel CaV1.2 and the AMPA-type glutamate receptor. Importantly, both complexes contain the trimeric Gs protein, adenylyl cyclase, and the cAMP-dependent protein kinase, PKA. We then discuss the functional implications of the formation of these complexes, how those complexes can be specifically disrupted, and how such disruption could be utilized in the pharmacological treatment of disease.
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Affiliation(s)
- Kwun Nok Mimi Man
- Department of Pharmacology, University of California, Davis, California 95616, USA;
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, California 95616, USA;
| | - Mary C Horne
- Department of Pharmacology, University of California, Davis, California 95616, USA;
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, California 95616, USA;
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20
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Higham JP, Hidalgo S, Buhl E, Hodge JJL. Restoration of Olfactory Memory in Drosophila Overexpressing Human Alzheimer's Disease Associated Tau by Manipulation of L-Type Ca 2+ Channels. Front Cell Neurosci 2019; 13:409. [PMID: 31551716 PMCID: PMC6746915 DOI: 10.3389/fncel.2019.00409] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 08/26/2019] [Indexed: 01/13/2023] Open
Abstract
The cellular underpinnings of memory deficits in Alzheimer’s disease (AD) are poorly understood. We utilized the tractable neural circuits sub-serving memory in Drosophila to investigate the role of impaired Ca2+ handling in memory deficits caused by expression of human 0N4R isoform of tau which is associated with AD. Expression of tau in mushroom body neuropils, or a subset of mushroom body output neurons, led to impaired memory. By using the Ca2+ reporter GCaMP6f, we observed changes in Ca2+ signaling when tau was expressed in these neurons, an effect that could be blocked by the L-type Ca2+ channel antagonist nimodipine or reversed by RNAi knock-down of the L-type channel gene. The L-type Ca2+ channel itself is required for memory formation, however, RNAi knock-down of the L-type Ca2+ channel in neurons overexpressing human tau resulted in flies whose memory is restored to levels equivalent to wild-type. Expression data suggest that Drosophila L-type Ca2+ channel mRNA levels are increased upon tau expression in neurons, thus contributing to the effects observed on memory and intracellular Ca2+ homeostasis. Together, our Ca2+ imaging and memory experiments suggest that expression of the 0N4R isoform of human tau increases the number of L-type Ca2+ channels in the membrane resulting in changes in neuronal excitability that can be ameliorated by RNAi knockdown or pharmacological blockade of L-type Ca2+ channels. This highlights a role for L-type Ca2+ channels in tauopathy and their potential as a therapeutic target for AD.
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Affiliation(s)
- James P Higham
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Sergio Hidalgo
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Edgar Buhl
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - James J L Hodge
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
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21
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Temido-Ferreira M, Coelho JE, Pousinha PA, Lopes LV. Novel Players in the Aging Synapse: Impact on Cognition. J Caffeine Adenosine Res 2019; 9:104-127. [PMID: 31559391 PMCID: PMC6761599 DOI: 10.1089/caff.2019.0013] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
While neuronal loss has long been considered as the main contributor to age-related cognitive decline, these alterations are currently attributed to gradual synaptic dysfunction driven by calcium dyshomeostasis and alterations in ionotropic/metabotropic receptors. Given the key role of the hippocampus in encoding, storage, and retrieval of memory, the morpho- and electrophysiological alterations that occur in the major synapse of this network-the glutamatergic-deserve special attention. We guide you through the hippocampal anatomy, circuitry, and function in physiological context and focus on alterations in neuronal morphology, calcium dynamics, and plasticity induced by aging and Alzheimer's disease (AD). We provide state-of-the art knowledge on glutamatergic transmission and discuss implications of these novel players for intervention. A link between regular consumption of caffeine-an adenosine receptor blocker-to decreased risk of AD in humans is well established, while the mechanisms responsible have only now been uncovered. We review compelling evidence from humans and animal models that implicate adenosine A2A receptors (A2AR) upsurge as a crucial mediator of age-related synaptic dysfunction. The relevance of this mechanism in patients was very recently demonstrated in the form of a significant association of the A2AR-encoding gene with hippocampal volume (synaptic loss) in mild cognitive impairment and AD. Novel pathways implicate A2AR in the control of mGluR5-dependent NMDAR activation and subsequent Ca2+ dysfunction upon aging. The nature of this receptor makes it particularly suited for long-term therapies, as an alternative for regulating aberrant mGluR5/NMDAR signaling in aging and disease, without disrupting their crucial constitutive activity.
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Affiliation(s)
- Mariana Temido-Ferreira
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Joana E. Coelho
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Paula A. Pousinha
- Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), CNRS UMR7275, Université Côte d'Azur, Valbonne, France
| | - Luísa V. Lopes
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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22
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Foster TC. Senescent neurophysiology: Ca 2+ signaling from the membrane to the nucleus. Neurobiol Learn Mem 2019; 164:107064. [PMID: 31394200 DOI: 10.1016/j.nlm.2019.107064] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/29/2019] [Accepted: 08/03/2019] [Indexed: 12/16/2022]
Abstract
The current review provides a historical perspective on the evolution of hypothesized mechanisms for senescent neurophysiology, focused on the CA1 region of the hippocampus, and the relationship of senescent neurophysiology to impaired hippocampal-dependent memory. Senescent neurophysiology involves processes linked to calcium (Ca2+) signaling including an increase in the Ca2+-dependent afterhyperpolarization (AHP), decreasing pyramidal cell excitability, hyporesponsiveness of N-methyl-D-aspartate (NMDA) receptor function, and a shift in Ca2+-dependent synaptic plasticity. Dysregulation of intracellular Ca2+ and downstream signaling of kinase and phosphatase activity lies at the core of senescent neurophysiology. Ca2+-dysregulation involves a decrease in Ca2+ influx through NMDA receptors and an increase release of Ca2+ from internal Ca2+ stores. Recent work has identified changes in redox signaling, arising in middle-age, as an initiating factor for senescent neurophysiology. The shift in redox state links processes of aging, oxidative stress and inflammation, with functional changes in mechanisms required for episodic memory. The link between age-related changes in Ca2+ signaling, epigenetics and gene expression is an exciting area of research. Pharmacological and behavioral intervention, initiated in middle-age, can promote memory function by initiating transcription of neuroprotective genes and rejuvenating neurophysiology. However, with more advanced age, or under conditions of neurodegenerative disease, epigenetic changes may weaken the link between environmental influences and transcription, decreasing resilience of memory function.
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Affiliation(s)
- Thomas C Foster
- Department of Neuroscience and Genetics and Genomics Program, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA.
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23
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Store depletion-induced h-channel plasticity rescues a channelopathy linked to Alzheimer's disease. Neurobiol Learn Mem 2018; 154:141-157. [PMID: 29906573 DOI: 10.1016/j.nlm.2018.06.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 05/25/2018] [Accepted: 06/11/2018] [Indexed: 12/20/2022]
Abstract
Voltage-gated ion channels are critical for neuronal integration. Some of these channels, however, are misregulated in several neurological disorders, causing both gain- and loss-of-function channelopathies in neurons. Using several transgenic mouse models of Alzheimer's disease (AD), we find that sub-threshold voltage signals strongly influenced by hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels progressively deteriorate over chronological aging in hippocampal CA1 pyramidal neurons. The degraded signaling via HCN channels in the transgenic mice is accompanied by an age-related global loss of their non-uniform dendritic expression. Both the aberrant signaling via HCN channels and their mislocalization could be restored using a variety of pharmacological agents that target the endoplasmic reticulum (ER). Our rescue of the HCN channelopathy helps provide molecular details into the favorable outcomes of ER-targeting drugs on the pathogenesis and synaptic/cognitive deficits in AD mouse models, and implies that they might have beneficial effects on neurological disorders linked to HCN channelopathies.
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24
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Deficiency of PRKD2 triggers hyperinsulinemia and metabolic disorders. Nat Commun 2018; 9:2015. [PMID: 29789568 PMCID: PMC5964083 DOI: 10.1038/s41467-018-04352-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 04/23/2018] [Indexed: 01/21/2023] Open
Abstract
Hyperinsulinemia is the earliest symptom of insulin resistance (IR), but a causal relationship between the two remains to be established. Here we show that a protein kinase D2 (PRKD2) nonsense mutation (K410X) in two rhesus monkeys with extreme hyperinsulinemia along with IR and metabolic defects by using extreme phenotype sampling and deep sequencing analyses. This mutation reduces PRKD2 at both the mRNA and the protein levels. Taking advantage of a PRKD2-KO mouse model, we demonstrate that PRKD2 deletion triggers hyperinsulinemia which precedes to IR and metabolic disorders in the PRKD2 ablation mice. PRKD2 deficiency promotes β-cell insulin secretion by increasing the expression and activity of L-type Ca2+ channels and subsequently augmenting high glucose- and membrane depolarization-induced Ca2+ influx. Altogether, these results indicate that down-regulation of PRKD2 is involved in the pathogenesis of hyperinsulinemia which, in turn, results in IR and metabolic disorders. Hyperinsulinemia can precede the development of insulin resistance. Here the authors identify a PKD2 mutation that leads to hyperinsulinemia and insulin resistance in Rhesus monkey and show that PKD2 deficiency promotes beta cell insulin secretion by activating L-type Ca2+ channels.
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25
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Altered function of neuronal L-type calcium channels in ageing and neuroinflammation: Implications in age-related synaptic dysfunction and cognitive decline. Ageing Res Rev 2018; 42:86-99. [PMID: 29339150 DOI: 10.1016/j.arr.2018.01.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 01/10/2018] [Accepted: 01/11/2018] [Indexed: 12/29/2022]
Abstract
The rapid developments in science have led to an increase in human life expectancy and thus, ageing and age-related disorders/diseases have become one of the greatest concerns in the 21st century. Cognitive abilities tend to decline as we get older. This age-related cognitive decline is mainly attributed to aberrant changes in synaptic plasticity and neuronal connections. Recent studies show that alterations in Ca2+ homeostasis underlie the increased vulnerability of neurons to age-related processes like cognitive decline and synaptic dysfunctions. Dysregulation of Ca2+ can lead to dramatic changes in neuronal functions. We discuss in this review, the recent advances on the potential role of dysregulated Ca2+ homeostasis through altered function of L-type voltage gated Ca2+ channels (LTCC) in ageing, with an emphasis on cognitive decline. This review therefore focuses on age-related changes mainly in the hippocampus, and with mention of other brain areas, that are important for learning and memory. This review also highlights age-related memory deficits via synaptic alterations and neuroinflammation. An understanding of these mechanisms will help us formulate strategies to reverse or ameliorate age-related disorders like cognitive decline.
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26
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Ghosh A, Carew SJ, Chen X, Yuan Q. The Role of L-type Calcium Channels in Olfactory Learning and Its Modulation by Norepinephrine. Front Cell Neurosci 2017; 11:394. [PMID: 29321726 PMCID: PMC5732138 DOI: 10.3389/fncel.2017.00394] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Accepted: 11/28/2017] [Indexed: 11/25/2022] Open
Abstract
L type calcium channels (LTCCs) are prevalent in different systems and hold immense importance for maintaining/performing selective functions. In the nervous system, CaV1.2 and CaV1.3 are emerging as critical modulators of neuronal functions. Although the general role of these calcium channels in modulating synaptic plasticity and memory has been explored, their role in olfactory learning is not well understood. In this review article we first discuss the role of LTCCs in olfactory learning especially focusing on early odor preference learning in neonate rodents, presenting evidence that while NMDARs initiate stimulus-specific learning, LTCCs promote protein-synthesis dependent long-term memory (LTM). Norepinephrine (NE) release from the locus coeruleus (LC) is essential for early olfactory learning, thus noradrenergic modulation of LTCC function and its implication in olfactory learning is discussed here. We then address the differential roles of LTCCs in adult learning and learning in aged animals.
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Affiliation(s)
- Abhinaba Ghosh
- Laboratory of Neuroscience, Department of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Samantha J Carew
- Laboratory of Neuroscience, Department of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Xihua Chen
- Laboratory of Neuroscience, Department of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Qi Yuan
- Laboratory of Neuroscience, Department of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
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27
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Sheng Y, Tang L, Kang L, Xiao R. Membrane ion Channels and Receptors in Animal lifespan Modulation. J Cell Physiol 2017; 232:2946-2956. [PMID: 28121014 PMCID: PMC7008462 DOI: 10.1002/jcp.25824] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 01/01/2023]
Abstract
Acting in the interfaces between environment and membrane compartments, membrane ion channels, and receptors transduce various physical and chemical cues into downstream signaling events. Not surprisingly, these membrane proteins play essential roles in a wide range of cellular processes such as sensory perception, synaptic transmission, cellular growth and development, fate determination, and apoptosis. However, except insulin and insulin-like growth factor receptors, the functions of membrane receptors in animal lifespan modulation have not been well appreciated. On the other hand, although ion channels are popular therapeutic targets for many age-related diseases, their potential roles in aging itself are largely neglected. In this review, we will discuss our current understanding of the conserved functions and mechanisms of membrane ion channels and receptors in the modulation of lifespan across multiple species including Caenorhabditis elegans, Drosophila, mouse, and human.
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Affiliation(s)
- Yi Sheng
- Division of Biology of Aging, Department of Aging and Geriatric Research, Institute on Aging, College of Medicine, University of Florida, Gainesville, Florida
| | - Lanlan Tang
- Division of Biology of Aging, Department of Aging and Geriatric Research, Institute on Aging, College of Medicine, University of Florida, Gainesville, Florida
| | - Lijun Kang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, China
| | - Rui Xiao
- Division of Biology of Aging, Department of Aging and Geriatric Research, Institute on Aging, College of Medicine, University of Florida, Gainesville, Florida
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, Florida
- Center for Smell and Taste, University of Florida, Gainesville, Florida
- Genetics Institute, University of Florida, Gainesville, Florida
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Maimaiti S, Frazier HN, Anderson KL, Ghoweri AO, Brewer LD, Porter NM, Thibault O. Novel calcium-related targets of insulin in hippocampal neurons. Neuroscience 2017; 364:130-142. [PMID: 28939258 DOI: 10.1016/j.neuroscience.2017.09.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 01/28/2023]
Abstract
Both insulin signaling disruption and Ca2+ dysregulation are closely related to memory loss during aging and increase the vulnerability to Alzheimer's disease (AD). In hippocampal neurons, aging-related changes in calcium regulatory pathways have been shown to lead to higher intracellular calcium levels and an increase in the Ca2+-dependent afterhyperpolarization (AHP), which is associated with cognitive decline. Recent studies suggest that insulin reduces the Ca2+-dependent AHP. Given the sensitivity of neurons to insulin and evidence that brain insulin signaling is reduced with age, insulin-mediated alterations in calcium homeostasis may underlie the beneficial actions of insulin in the brain. Indeed, increasing insulin signaling in the brain via intranasal delivery has yielded promising results such as improving memory in both clinical and animal studies. However, while several mechanisms have been proposed, few have focused on regulation on intracellular Ca2+. In the present study, we further examined the effects of acute insulin on calcium pathways in primary hippocampal neurons in culture. Using the whole-cell patch-clamp technique, we found that acute insulin delivery reduced voltage-gated calcium currents. Fura-2 imaging was used to also address acute insulin effects on spontaneous and depolarization-mediated Ca2+ transients. Results indicate that insulin reduced Ca2+ transients, which appears to have involved a reduction in ryanodine receptor function. Together, these results suggest insulin regulates pathways that control intracellular Ca2+ which may reduce the AHP and improve memory. This may be one mechanism contributing to improved memory recall in response to intranasal insulin therapy in the clinic.
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Affiliation(s)
- Shaniya Maimaiti
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Hilaree N Frazier
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Katie L Anderson
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Adam O Ghoweri
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Lawrence D Brewer
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Nada M Porter
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States
| | - Olivier Thibault
- Department of Pharmacology and Nutritional Sciences, University of Kentucky Medical Center, UKMC, MS-310; 800 Rose Street, Lexington, KY 40536, United States.
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Differential Roles for L-Type Calcium Channel Subtypes in Alcohol Dependence. Neuropsychopharmacology 2017; 42:1058-1069. [PMID: 27905406 PMCID: PMC5506795 DOI: 10.1038/npp.2016.266] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Revised: 11/24/2016] [Accepted: 11/25/2016] [Indexed: 12/14/2022]
Abstract
It has previously been shown that the inhibition of L-type calcium channels (LTCCs) decreases alcohol consumption, although the contribution of the central LTCC subtypes Cav1.2 and Cav1.3 remains unknown. Here, we determined changes in Cav1.2 (Cacna1c) and Cav1.3 (Cacna1d) mRNA and protein expression in alcohol-dependent rats during protracted abstinence and naive controls using in situ hybridization and western blot analysis. Functional validation was obtained by electrophysiological recordings of calcium currents in dissociated hippocampal pyramidal neurons. We then measured alcohol self-administration and cue-induced reinstatement of alcohol seeking in dependent and nondependent rats after intracerebroventricular (i.c.v.) injection of the LTCC antagonist verapamil, as well as in mice with an inducible knockout (KO) of Cav1.2 in Ca2+/calmodulin-dependent protein kinase IIα (CaMKIIα)-expressing neurons. Our results show that Cacna1c mRNA concentration was increased in the amygdala and hippocampus of alcohol-dependent rats after 21 days of abstinence, with no changes in Cacna1d mRNA. This was associated with increased Cav1.2 protein concentration and L-type calcium current amplitudes. Further analysis of Cacna1c mRNA in the CA1, basolateral amygdala (BLA), and central amygdala (CeA) revealed a dynamic regulation over time during the development of alcohol dependence. The inhibition of central LTCCs via i.c.v. administration of verapamil prevented cue-induced reinstatement of alcohol seeking in alcohol-dependent rats. Further studies in conditional Cav1.2-KO mice showed a lack of dependence-induced increase of alcohol-seeking behavior. Together, our data indicate that central Cav1.2 channels, rather than Cav1.3, mediate alcohol-seeking behavior. This finding may be of interest for the development of new antirelapse medications.
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Yu XW, Curlik DM, Oh MM, Yin JC, Disterhoft JF. CREB overexpression in dorsal CA1 ameliorates long-term memory deficits in aged rats. eLife 2017; 6. [PMID: 28051768 PMCID: PMC5214885 DOI: 10.7554/elife.19358] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 12/15/2016] [Indexed: 11/20/2022] Open
Abstract
The molecular mechanisms underlying age-related cognitive deficits are not yet fully elucidated. In aged animals, a decrease in the intrinsic excitability of CA1 pyramidal neurons is believed to contribute to age-related cognitive impairments. Increasing activity of the transcription factor cAMP response element-binding protein (CREB) in young adult rodents facilitates cognition, and increases intrinsic excitability. However, it has yet to be tested if increasing CREB expression also ameliorates age-related behavioral and biophysical deficits. To test this hypothesis, we virally overexpressed CREB in CA1 of dorsal hippocampus. Rats received CREB or control virus, before undergoing water maze training. CREB overexpression in aged animals ameliorated the long-term memory deficits observed in control animals. Concurrently, cells overexpressing CREB in aged animals had reduced post-burst afterhyperpolarizations, indicative of increased intrinsic excitability. These results identify CREB modulation as a potential therapy to treat age-related cognitive decline. DOI:http://dx.doi.org/10.7554/eLife.19358.001
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Affiliation(s)
- Xiao-Wen Yu
- Department of Physiology, Northwestern University,Feinberg School of Medicine, Chicago, United States
| | - Daniel M Curlik
- Department of Physiology, Northwestern University,Feinberg School of Medicine, Chicago, United States.,Department of Behavioral Sciences, Psychology Program, York College of Pennsylvania, York, United States
| | - M Matthew Oh
- Department of Physiology, Northwestern University,Feinberg School of Medicine, Chicago, United States
| | - Jerry Cp Yin
- Departments of Genetics and Neurology, University of Wisconsin-Madison, Madison, United States
| | - John F Disterhoft
- Department of Physiology, Northwestern University,Feinberg School of Medicine, Chicago, United States
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31
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Villanueva-Castillo C, Tecuatl C, Herrera-López G, Galván EJ. Aging-related impairments of hippocampal mossy fibers synapses on CA3 pyramidal cells. Neurobiol Aging 2016; 49:119-137. [PMID: 27794263 DOI: 10.1016/j.neurobiolaging.2016.09.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 09/15/2016] [Accepted: 09/17/2016] [Indexed: 11/16/2022]
Abstract
The network interaction between the dentate gyrus and area CA3 of the hippocampus is responsible for pattern separation, a process that underlies the formation of new memories, and which is naturally diminished in the aged brain. At the cellular level, aging is accompanied by a progression of biochemical modifications that ultimately affects its ability to generate and consolidate long-term potentiation. Although the synapse between dentate gyrus via the mossy fibers (MFs) onto CA3 neurons has been subject of extensive studies, the question of how aging affects the MF-CA3 synapse is still unsolved. Extracellular and whole-cell recordings from acute hippocampal slices of aged Wistar rats (34 ± 2 months old) show that aging is accompanied by a reduction in the interneuron-mediated inhibitory mechanisms of area CA3. Several MF-mediated forms of short-term plasticity, MF long-term potentiation and at least one of the critical signaling cascades necessary for potentiation are also compromised in the aged brain. An analysis of the spontaneous glutamatergic and gamma-aminobutyric acid-mediated currents on CA3 cells reveal a dramatic alteration in amplitude and frequency of the nonevoked events. CA3 cells also exhibited increased intrinsic excitability. Together, these results demonstrate that aging is accompanied by a decrease in the GABAergic inhibition, reduced expression of short- and long-term forms of synaptic plasticity, and increased intrinsic excitability.
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Affiliation(s)
| | - Carolina Tecuatl
- Departamento de Farmacobiología, Cinvestav Sede Sur, México City, México
| | | | - Emilio J Galván
- Departamento de Farmacobiología, Cinvestav Sede Sur, México City, México.
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Krueger JN, Moore SJ, Parent R, McKinney BC, Lee A, Murphy GG. A novel mouse model of the aged brain: Over-expression of the L-type voltage-gated calcium channel Ca V1.3. Behav Brain Res 2016; 322:241-249. [PMID: 27368417 DOI: 10.1016/j.bbr.2016.06.054] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 06/09/2016] [Accepted: 06/27/2016] [Indexed: 11/16/2022]
Abstract
The aged population is growing rapidly, which has sparked tremendous interest in elucidating mechanisms of aging in both the body and the brain. Animal models have become an indispensable tool in biomedical science, but because of the cost and extended timeframe associated with aging animals to appropriate time points, studies that rely on using aged animals are often not feasible. Somewhat surprisingly, there are relatively few animal models that have been specifically engineered to mimic physiological changes known to occur during "normal" aging. Developing transgenic animal models that faithfully mimic key aspects of aging would likely be of great utility in studying both age-related deficits in the absence of overt pathology as well as an adjunct for transgenic models of diseases where aging is a primary risk factor. In particular, there are several alterations in the aged brain that are amenable to being modeled genetically. We have focused on one key aspect that has been repeatedly demonstrated in aged animals - an increase in the L-type voltage-gated calcium channel CaV1.3. Here we present a novel transgenic mouse line in which expression of CaV1.3 is increased by approximately 50% in the forebrain of young mice. These mice do not display any overt physical or non-cognitive deficits, exhibiting normal exploratory behavior, motor function, and affective-like responses, suggesting that these mice can be successfully deployed to assess the impact of an "aged brain" in a variety of conditions.
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Affiliation(s)
- Jamie N Krueger
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States
| | - Shannon J Moore
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States.
| | - Rachel Parent
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States
| | - Brandon C McKinney
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States
| | - Amy Lee
- Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA 52242, United States
| | - Geoffrey G Murphy
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, United States; Department of Physiology, University of Michigan, Ann Arbor, MI 48109, United States.
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Oh MM, Simkin D, Disterhoft JF. Intrinsic Hippocampal Excitability Changes of Opposite Signs and Different Origins in CA1 and CA3 Pyramidal Neurons Underlie Aging-Related Cognitive Deficits. Front Syst Neurosci 2016; 10:52. [PMID: 27375440 PMCID: PMC4899460 DOI: 10.3389/fnsys.2016.00052] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 05/27/2016] [Indexed: 11/13/2022] Open
Abstract
Aging-related cognitive deficits have been attributed to dysfunction of neurons due to failures at synaptic or intrinsic loci, or both. Given the importance of the hippocampus for successful encoding of memory and that the main output of the hippocampus is via the CA1 pyramidal neurons, much of the research has been focused on identifying the aging-related changes of these CA1 pyramidal neurons. We and others have discovered that the postburst afterhyperpolarization (AHP) following a train of action potentials is greatly enlarged in CA1 pyramidal neurons of aged animals. This enlarged postburst AHP is a significant factor in reducing the intrinsic excitability of these neurons, and thus limiting their activity in the neural network during learning. Based on these data, it has largely been thought that aging-related cognitive deficits are attributable to reduced activity of pyramidal neurons. However, recent in vivo and ex vivo studies provide compelling evidence that aging-related deficits could also be due to a converse change in CA3 pyramidal neurons, which show increased activity with aging. In this review, we will incorporate these recent findings and posit that an interdependent dynamic dysfunctional change occurs within the hippocampal network, largely due to altered intrinsic excitability in CA1 and CA3 hippocampal pyramidal neurons, which ultimately leads to the aging-related cognitive deficits.
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Affiliation(s)
- M Matthew Oh
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - Dina Simkin
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - John F Disterhoft
- Department of Physiology, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
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Aging-Related Hyperexcitability in CA3 Pyramidal Neurons Is Mediated by Enhanced A-Type K+ Channel Function and Expression. J Neurosci 2015; 35:13206-18. [PMID: 26400949 DOI: 10.1523/jneurosci.0193-15.2015] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aging-related impairments in hippocampus-dependent cognition have been attributed to maladaptive changes in the functional properties of pyramidal neurons within the hippocampal subregions. Much evidence has come from work on CA1 pyramidal neurons, with CA3 pyramidal neurons receiving comparatively less attention despite its age-related hyperactivation being postulated to interfere with spatial processing in the hippocampal circuit. Here, we use whole-cell current-clamp to demonstrate that aged rat (29-32 months) CA3 pyramidal neurons fire significantly more action potentials (APs) during theta-burst frequency stimulation and that this is associated with faster AP repolarization (i.e., narrower AP half-widths and enlarged fast afterhyperpolarization). Using a combination of patch-clamp physiology, pharmacology, Western blot analyses, immunohistochemistry, and array tomography, we demonstrate that these faster AP kinetics are mediated by enhanced function and expression of Kv4.2/Kv4.3 A-type K(+) channels, particularly within the perisomatic compartment, of CA3 pyramidal neurons. Thus, our study indicates that inhibition of these A-type K(+) channels can restore the intrinsic excitability properties of aged CA3 pyramidal neurons to a young-like state. Significance statement: Age-related learning deficits have been attributed, in part, to altered hippocampal pyramidal neuronal function with normal aging. Much evidence has come from work on CA1 neurons, with CA3 neurons receiving comparatively less attention despite its age-related hyperactivation being postulated to interfere with spatial processing. Hence, we conducted a series of experiments to identify the cellular mechanisms that underlie the hyperexcitability reported in the CA3 region. Contrary to CA1 neurons, we demonstrate that postburst afterhyperpolarization is not altered with aging and that aged CA3 pyramidal neurons are able to fire significantly more action potentials and that this is associated with faster action potential repolarization through enhanced expression of Kv4.2/Kv4.3 A-type K(+) channels, particularly within the cell bodies of CA3 pyramidal neurons.
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Marschallinger J, Sah A, Schmuckermair C, Unger M, Rotheneichner P, Kharitonova M, Waclawiczek A, Gerner P, Jaksch-Bogensperger H, Berger S, Striessnig J, Singewald N, Couillard-Despres S, Aigner L. The L-type calcium channel Cav1.3 is required for proper hippocampal neurogenesis and cognitive functions. Cell Calcium 2015; 58:606-16. [PMID: 26459417 DOI: 10.1016/j.ceca.2015.09.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 09/04/2015] [Accepted: 09/29/2015] [Indexed: 11/29/2022]
Abstract
L-type voltage gated Ca(2+) channels (LTCCs) are widely expressed within different brain regions including the hippocampus. The isoforms Cav1.2 and Cav1.3 have been shown to be involved in hippocampus-dependent learning and memory, cognitive functions that require proper hippocampal neurogenesis. In vitro, functional LTCCs are expressed on neuronal progenitor cells, where they promote neuronal differentiation. Expression of LTCCs on neural stem and progenitor cells within the neurogenic regions in the adult brain in vivo has not been examined so far, and a contribution of the individual isoforms Cav1.2 and Cav1.3 to adult neurogenesis remained to be clarified. To reveal the role of these channels we first evaluated the expression patterns of Cav1.2 and Cav1.3 in the hippocampal dentate gyrus and the subventricular zone (SVZ) in adult (2- and 3-month old) and middle-aged (15-month old) mice on mRNA and protein levels. We performed immunohistological analysis of hippocampal neurogenesis in adult and middle-aged Cav1.3(-/-) mice and finally addressed the importance of Cav1.3 for hippocampal function by evaluating spatial memory and depression-like behavior in adult Cav1.3(-/-) mice. Our results showed Cav1.2 and Cav1.3 expression at different stages of neuronal differentiation. While Cav1.2 was primarily restricted to mature NeuN(+) granular neurons, Cav1.3 was expressed in Nestin(+) neural stem cells and in mature NeuN(+) granular neurons. Adult and middle-aged Cav1.3(-/-) mice showed severe impairments in dentate gyrus neurogenesis, with significantly smaller dentate gyrus volume, reduced survival of newly generated cells, and reduced neuronal differentiation. Further, Cav1.3(-/-) mice showed impairment in the hippocampus dependent object location memory test, implicating Cav1.3 as an essential element for hippocampus-associated cognitive functions. Thus, modulation of LTCC activities may have a crucial impact on neurogenic responses and cognition, which should be considered for future therapeutic administration of LTCCs modulators.
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Affiliation(s)
- Julia Marschallinger
- Institute of Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), Paracelsus Medical University, Salzburg, Austria
| | - Anupam Sah
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens-University of Innsbruck, Innsbruck, Austria
| | - Claudia Schmuckermair
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens-University of Innsbruck, Innsbruck, Austria
| | - Michael Unger
- Institute of Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), Paracelsus Medical University, Salzburg, Austria
| | - Peter Rotheneichner
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), Paracelsus Medical University, Salzburg, Austria; Institute of Experimental Neuroregeneration, Paracelsus Medical University, Salzburg, Austria
| | - Maria Kharitonova
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens-University of Innsbruck, Innsbruck, Austria
| | - Alexander Waclawiczek
- Institute of Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), Paracelsus Medical University, Salzburg, Austria
| | - Philipp Gerner
- Institute of Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), Paracelsus Medical University, Salzburg, Austria
| | - Heidi Jaksch-Bogensperger
- Institute of Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), Paracelsus Medical University, Salzburg, Austria
| | - Stefan Berger
- Department of Molecular Biology, Central Institute of Mental Health and Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Jörg Striessnig
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens-University of Innsbruck, Innsbruck, Austria
| | - Nicolas Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens-University of Innsbruck, Innsbruck, Austria
| | - Sebastien Couillard-Despres
- Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), Paracelsus Medical University, Salzburg, Austria; Institute of Experimental Neuroregeneration, Paracelsus Medical University, Salzburg, Austria
| | - Ludwig Aigner
- Institute of Molecular Regenerative Medicine, Paracelsus Medical University, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center Salzburg (SCI-TReCS), Paracelsus Medical University, Salzburg, Austria.
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Zanos P, Bhat S, Terrillion CE, Smith RJ, Tonelli LH, Gould TD. Sex-dependent modulation of age-related cognitive decline by the L-type calcium channel gene Cacna1c (Cav 1.2). Eur J Neurosci 2015; 42:2499-507. [PMID: 25989111 PMCID: PMC4615431 DOI: 10.1111/ejn.12952] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 04/27/2015] [Accepted: 05/14/2015] [Indexed: 11/27/2022]
Abstract
Increased calcium influx through L-type voltage-gated calcium channels has been implicated in the neuronal dysfunction underlying age-related memory declines. The present study aimed to test the specific role of Cacna1c (which encodes Cav 1.2) in modulating age-related memory dysfunction. Short-term, spatial and contextual/emotional memory was evaluated in young and aged, wild-type as well as mice with one functional copy of Cacna1c (haploinsufficient), using the novel object recognition, Y-maze and passive avoidance tasks, respectively. Hippocampal expression of Cacna1c mRNA was measured by quantitative polymerase chain reaction. Ageing was associated with object recognition and contextual/emotional memory deficits, and a significant increase in hippocampal Cacna1c mRNA expression. Cacna1c haploinsufficiency was associated with decreased Cacna1c mRNA expression in both young and old animals. However, haploinsufficient mice did not manifest an age-related increase in expression of this gene. Behaviourally, Cacna1c haploinsufficiency prevented object recognition deficits during ageing in both male and female mice. A significant correlation between higher Cacna1c levels and decreased object recognition performance was observed in both sexes. Also, a sex-dependent protective role of decreased Cacna1c levels in contextual/emotional memory loss has been observed, specifically in male mice. These data provide evidence for an association between increased hippocampal Cacna1c expression and age-related cognitive decline. Additionally, they indicate an interaction between the Cacna1c gene and sex in the modulation of age-related contextual memory declines.
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Affiliation(s)
- Panos Zanos
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
| | - Shambhu Bhat
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
| | | | - Robert J. Smith
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
| | - Leonardo H. Tonelli
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
| | - Todd D. Gould
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD
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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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Aging decreases L-type calcium channel currents and pacemaker firing fidelity in substantia nigra dopamine neurons. J Neurosci 2014; 34:9310-8. [PMID: 25009264 DOI: 10.1523/jneurosci.4228-13.2014] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Substantia nigra dopamine neurons are involved in behavioral processes that include cognition, reward learning, and voluntary movement. Selective deterioration of these neurons is responsible for the motor deficits associated with Parkinson's disease (PD). Aging is the leading risk factor for PD, suggesting that adaptations occurring in dopamine neurons during normal aging may predispose individuals to the development of PD. Previous studies suggest that the unique set of ion conductances that drive spontaneous, rhythmic firing of action potentials could predispose substantia nigra dopamine neurons to selective neurodegeneration. Here we show, using patch-clamp electrophysiological recordings in brain slices, that substantia nigra dopamine neurons from mice 25-30 months of age (old) have comparable membrane capacitance and input resistance to neurons from mice 2-7 months of age (young). However, neurons from old mice exhibit slower firing rates, narrower spike widths, and more variable interspike intervals compared with neurons from young mice. Dopamine neurons from old mice also exhibit smaller L-type calcium channel currents, providing a plausible mechanism that likely contributes to the changes in impulse activity. Age-related decrements in the physiological function of dopamine neurons could contribute to the decrease in voluntary movement and other dopamine-mediated behaviors observed in aging populations. Furthermore, as pharmacological antagonism of L-type calcium channels has been proposed as a potential treatment for the early stages of PD, our results could point to a limited temporal window of opportunity for this therapeutic intervention.
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