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Niemeyer N, Schleimer JH, Schreiber S. Biophysical models of intrinsic homeostasis: Firing rates and beyond. Curr Opin Neurobiol 2021; 70:81-88. [PMID: 34454303 DOI: 10.1016/j.conb.2021.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 06/14/2021] [Accepted: 07/14/2021] [Indexed: 12/01/2022]
Abstract
In view of ever-changing conditions both in the external world and in intrinsic brain states, maintaining the robustness of computations poses a challenge, adequate solutions to which we are only beginning to understand. At the level of cell-intrinsic properties, biophysical models of neurons permit one to identify relevant physiological substrates that can serve as regulators of neuronal excitability and to test how feedback loops can stabilize crucial variables such as long-term calcium levels and firing rates. Mathematical theory has also revealed a rich set of complementary computational properties arising from distinct cellular dynamics and even shaping processing at the network level. Here, we provide an overview over recently explored homeostatic mechanisms derived from biophysical models and hypothesize how multiple dynamical characteristics of cells, including their intrinsic neuronal excitability classes, can be stably controlled.
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Affiliation(s)
- Nelson Niemeyer
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, 10115, Berlin, Germany; Einstein Center for Neurosciences Berlin, Charitéplatz 1, 10117, Berlin, Germany; Bernstein Center for Computational Neuroscience, 10115, Berlin, Germany
| | - Jan-Hendrik Schleimer
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, 10115, Berlin, Germany; Bernstein Center for Computational Neuroscience, 10115, Berlin, Germany
| | - Susanne Schreiber
- Institute for Theoretical Biology, Humboldt-Universität zu Berlin, 10115, Berlin, Germany; Einstein Center for Neurosciences Berlin, Charitéplatz 1, 10117, Berlin, Germany; Bernstein Center for Computational Neuroscience, 10115, Berlin, Germany.
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52
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Dagra A, Miller DR, Lin M, Gopinath A, Shaerzadeh F, Harris S, Sorrentino ZA, Støier JF, Velasco S, Azar J, Alonge AR, Lebowitz JJ, Ulm B, Bu M, Hansen CA, Urs N, Giasson BI, Khoshbouei H. α-Synuclein-induced dysregulation of neuronal activity contributes to murine dopamine neuron vulnerability. NPJ Parkinsons Dis 2021; 7:76. [PMID: 34408150 PMCID: PMC8373893 DOI: 10.1038/s41531-021-00210-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 07/09/2021] [Indexed: 02/07/2023] Open
Abstract
Pathophysiological damages and loss of function of dopamine neurons precede their demise and contribute to the early phases of Parkinson's disease. The presence of aberrant intracellular pathological inclusions of the protein α-synuclein within ventral midbrain dopaminergic neurons is one of the cardinal features of Parkinson's disease. We employed molecular biology, electrophysiology, and live-cell imaging to investigate how excessive α-synuclein expression alters multiple characteristics of dopaminergic neuronal dynamics and dopamine transmission in cultured dopamine neurons conditionally expressing GCaMP6f. We found that overexpression of α-synuclein in mouse (male and female) dopaminergic neurons altered neuronal firing properties, calcium dynamics, dopamine release, protein expression, and morphology. Moreover, prolonged exposure to the D2 receptor agonist, quinpirole, rescues many of the alterations induced by α-synuclein overexpression. These studies demonstrate that α-synuclein dysregulation of neuronal activity contributes to the vulnerability of dopaminergic neurons and that modulation of D2 receptor activity can ameliorate the pathophysiology. These findings provide mechanistic insights into the insidious changes in dopaminergic neuronal activity and neuronal loss that characterize Parkinson's disease progression with significant therapeutic implications.
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Affiliation(s)
- Abeer Dagra
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Douglas R. Miller
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Min Lin
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Adithya Gopinath
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Fatemeh Shaerzadeh
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Sharonda Harris
- grid.15276.370000 0004 1936 8091Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL USA
| | - Zachary A. Sorrentino
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Jonatan Fullerton Støier
- grid.5254.60000 0001 0674 042XMolecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sophia Velasco
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Janelle Azar
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Adetola R. Alonge
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Joseph J. Lebowitz
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Brittany Ulm
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Mengfei Bu
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Carissa A. Hansen
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Nikhil Urs
- grid.15276.370000 0004 1936 8091Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL USA
| | - Benoit I. Giasson
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
| | - Habibeh Khoshbouei
- grid.15276.370000 0004 1936 8091Department of Neuroscience, University of Florida, Gainesville, FL USA
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53
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Jaras I, Harada T, Orchard ME, Maldonado PE, Vergara RC. Extending the integrate-and-fire model to account for metabolic dependencies. Eur J Neurosci 2021; 54:5249-5260. [PMID: 34109698 DOI: 10.1111/ejn.15326] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 05/06/2021] [Accepted: 05/23/2021] [Indexed: 12/24/2022]
Abstract
It is widely accepted that the brain, like any other physical system, is subjected to physical constraints that restrict its operation. The brain's metabolic demands are particularly critical for proper neuronal function, but the impact of these constraints continues to remain poorly understood. Detailed single-neuron models are recently integrating metabolic constraints, but these models' computational resources make it challenging to explore the dynamics of extended neural networks, which are governed by such constraints. Thus, there is a need for a simplified neuron model that incorporates metabolic activity and allows us to explore the dynamics of neural networks. This work introduces an energy-dependent leaky integrate-and-fire (EDLIF) neuronal model extension to account for the effects of metabolic constraints on the single-neuron behavior. This simple, energy-dependent model could describe the relationship between the average firing rate and the Adenosine triphosphate (ATP) cost as well as replicate a neuron's behavior under a clinical setting such as amyotrophic lateral sclerosis (ALS). Additionally, EDLIF model showed better performance in predicting real spike trains - in the sense of spike coincidence measure - than the classical leaky integrate-and-fire (LIF) model. The simplicity of the energy-dependent model presented here makes it computationally efficient and, thus, suitable for studying the dynamics of large neural networks.
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Affiliation(s)
- Ismael Jaras
- Department of Electrical Engineering, Faculty of Mathematical and Physical Sciences, University of Chile, Santiago, Chile.,Neurosystems Laboratory, Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Taiki Harada
- Tokyo Medical and Dental University, Tokyo, Japan
| | - Marcos E Orchard
- Department of Electrical Engineering, Faculty of Mathematical and Physical Sciences, University of Chile, Santiago, Chile
| | - Pedro E Maldonado
- Neurosystems Laboratory, Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Rodrigo C Vergara
- Kinesiology Department, Facultad de Artes y Educación Física, Universidad Metropolitana de Ciencias de la Educación, Santiago, Chile
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54
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Jadiya P, Garbincius JF, Elrod JW. Reappraisal of metabolic dysfunction in neurodegeneration: Focus on mitochondrial function and calcium signaling. Acta Neuropathol Commun 2021; 9:124. [PMID: 34233766 PMCID: PMC8262011 DOI: 10.1186/s40478-021-01224-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/27/2021] [Indexed: 02/06/2023] Open
Abstract
The cellular and molecular mechanisms that drive neurodegeneration remain poorly defined. Recent clinical trial failures, difficult diagnosis, uncertain etiology, and lack of curative therapies prompted us to re-examine other hypotheses of neurodegenerative pathogenesis. Recent reports establish that mitochondrial and calcium dysregulation occur early in many neurodegenerative diseases (NDDs), including Alzheimer's disease, Parkinson's disease, Huntington's disease, and others. However, causal molecular evidence of mitochondrial and metabolic contributions to pathogenesis remains insufficient. Here we summarize the data supporting the hypothesis that mitochondrial and metabolic dysfunction result from diverse etiologies of neuropathology. We provide a current and comprehensive review of the literature and interpret that defective mitochondrial metabolism is upstream and primary to protein aggregation and other dogmatic hypotheses of NDDs. Finally, we identify gaps in knowledge and propose therapeutic modulation of mCa2+ exchange and mitochondrial function to alleviate metabolic impairments and treat NDDs.
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Affiliation(s)
- Pooja Jadiya
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, 3500 N Broad St, MERB 949, Philadelphia, PA, 19140, USA
| | - Joanne F Garbincius
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, 3500 N Broad St, MERB 949, Philadelphia, PA, 19140, USA
| | - John W Elrod
- Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, 3500 N Broad St, MERB 949, Philadelphia, PA, 19140, USA.
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Kumar BS, Khot A, Chakravarthy VS, Pushpavanam S. A Network Architecture for Bidirectional Neurovascular Coupling in Rat Whisker Barrel Cortex. Front Comput Neurosci 2021; 15:638700. [PMID: 34211384 PMCID: PMC8241226 DOI: 10.3389/fncom.2021.638700] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 05/10/2021] [Indexed: 01/01/2023] Open
Abstract
Neurovascular coupling is typically considered as a master-slave relationship between the neurons and the cerebral vessels: the neurons demand energy which the vessels supply in the form of glucose and oxygen. In the recent past, both theoretical and experimental studies have suggested that the neurovascular coupling is a bidirectional system, a loop that includes a feedback signal from the vessels influencing neural firing and plasticity. An integrated model of bidirectionally connected neural network and the vascular network is hence required to understand the relationship between the informational and metabolic aspects of neural dynamics. In this study, we present a computational model of the bidirectional neurovascular system in the whisker barrel cortex and study the effect of such coupling on neural activity and plasticity as manifest in the whisker barrel map formation. In this model, a biologically plausible self-organizing network model of rate coded, dynamic neurons is nourished by a network of vessels modeled using the biophysical properties of blood vessels. The neural layer which is designed to simulate the whisker barrel cortex of rat transmits vasodilatory signals to the vessels. The feedback from the vessels is in the form of available oxygen for oxidative metabolism whose end result is the adenosine triphosphate (ATP) necessary to fuel neural firing. The model captures the effect of the feedback from the vascular network on the neuronal map formation in the whisker barrel model under normal and pathological (Hypoxia and Hypoxia-Ischemia) conditions.
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Affiliation(s)
- Bhadra S. Kumar
- Computational Neuroscience Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, India
| | - Aditi Khot
- Department of Chemical Engineering, Purdue University, West Lafayette, IN, United States
| | - V. Srinivasa Chakravarthy
- Computational Neuroscience Laboratory, Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, India
| | - S. Pushpavanam
- Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai, India
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56
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Analyzing Olfactory Neuron Precursors Non-Invasively Isolated through NADH FLIM as a Potential Tool to Study Oxidative Stress in Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms22126311. [PMID: 34204595 PMCID: PMC8231156 DOI: 10.3390/ijms22126311] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/29/2021] [Accepted: 04/29/2021] [Indexed: 12/22/2022] Open
Abstract
Among all the proposed pathogenic mechanisms to understand the etiology of Alzheimer’s disease (AD), increased oxidative stress seems to be a robust and early disease feature where many of those hypotheses converge. However, despite the significant lines of evidence accumulated, an effective diagnosis and treatment of AD are not yet available. This limitation might be partially explained by the use of cellular and animal models that recapitulate partial aspects of the disease and do not account for the particular biology of patients. As such, cultures of patient-derived cells of peripheral origin may provide a convenient solution for this problem. Peripheral cells of neuronal lineage such as olfactory neuronal precursors (ONPs) can be easily cultured through non-invasive isolation, reproducing AD-related oxidative stress. Interestingly, the autofluorescence of key metabolic cofactors such as reduced nicotinamide adenine dinucleotide (NADH) can be highly correlated with the oxidative state and antioxidant capacity of cells in a non-destructive and label-free manner. In particular, imaging NADH through fluorescence lifetime imaging microscopy (FLIM) has greatly improved the sensitivity in detecting oxidative shifts with minimal intervention to cell physiology. Here, we discuss the translational potential of analyzing patient-derived ONPs non-invasively isolated through NADH FLIM to reveal AD-related oxidative stress. We believe this approach may potentially accelerate the discovery of effective antioxidant therapies and contribute to early diagnosis and personalized monitoring of this devastating disease.
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Riegler B, Polani D, Steuber V. Embodiment and Its Influence on Informational Costs of Decision Density-Atomic Actions vs. Scripted Sequences. Front Robot AI 2021; 8:535158. [PMID: 33996919 PMCID: PMC8121084 DOI: 10.3389/frobt.2021.535158] [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: 02/14/2020] [Accepted: 01/25/2021] [Indexed: 12/03/2022] Open
Abstract
The importance of embodiment for effective robot performance has been postulated for a long time. Despite this, only relatively recently concrete quantitative models were put forward to characterize the advantages provided by a well-chosen embodiment. We here use one of these models, based on the concept of relevant information, to identify in a minimalistic scenario how and when embodiment affects the decision density. Concretely, we study how embodiment affects information costs when, instead of atomic actions, scripts are introduced, that is, predefined action sequences. Their inclusion can be treated as a straightforward extension of the basic action space. We will demonstrate the effect on informational decision cost of utilizing scripts vs. basic actions using a simple navigation task. Importantly, we will also employ a world with "mislabeled" actions, which we will call a "twisted" world. This is a model which had been used in an earlier study of the influence of embodiment on decision costs. It will turn out that twisted scenarios, as opposed to well-labeled ("embodied") ones, are significantly more costly in terms of relevant information. This cost is further worsened when the agent is forced to lower the decision density by employing scripts (once a script is triggered, no decisions are taken until the script has run to its end). This adds to our understanding why well-embodied (interpreted in our model as well-labeled) agents should be preferable, in a quantifiable, objective sense.
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Affiliation(s)
- Bente Riegler
- Sepia Lab, Adaptive Systems Group, School of Engineering and Computer Science, University of Hertfordshire, Hatfield, United Kingdom
| | - Daniel Polani
- Sepia Lab, Adaptive Systems Group, School of Engineering and Computer Science, University of Hertfordshire, Hatfield, United Kingdom
| | - Volker Steuber
- Biocomputation Research Group, School of Engineering and Computer Science, University of Hertfordshire, Hatfield, United Kingdom
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Abstract
PURPOSE OF REVIEW The present review aims to address the clinical benefits of using nicotinamide riboside, a precursor to the essential pyridine nucleotide, nicotinamide adenine dinucleotide (NAD+) as a therapeutic agent to attenuate age-related cognitive decline. RECENT FINDINGS Oral supplementation with nicotinamide riboside can inhibit the accumulation of pathological hallmarks of Alzheimer's disease and improve learning and memory in various murine models for dementia. Nicotinamide riboside can also reduce DNA damage, neuroinflammation, apoptosis, and improved hippocampal synaptic plasticity in diabetic mice, and another Alzheimer's disease mouse model. The cognitive benefits of nicotinamide riboside in Alzheimer's disease models may be modulated in part by upregulation of proliferator-activated-γ coactivator 1α-mediated β-secretase 1(BACE-1) ubiquitination and degradation, preventing Aβ production in the brain. Nicotinamide riboside also maintained blood-brain barrier integrity and maintained the gut microbiota in a mouse model for cerebral small vessel disease and alcohol-induced depression, respectively. Oral nicotinamide riboside has been shown to be bioavailable and well tolerated in humans with limited adverse effects compared to other NAD+ precursors. SUMMARY Oral nicotinamide riboside may represent a promising stratagem to improve cognitive decline during 'normal' ageing, Alzheimer's disease and other diseases. Results from recent clinical trials are needed to enumerate the preclinical benefits in humans.
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Affiliation(s)
- Nady Braidy
- Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Sydney, Australia
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59
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Panchal K, Tiwari AK. Miro (Mitochondrial Rho GTPase), a key player of mitochondrial axonal transport and mitochondrial dynamics in neurodegenerative diseases. Mitochondrion 2020; 56:118-135. [PMID: 33127590 DOI: 10.1016/j.mito.2020.10.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 10/14/2020] [Accepted: 10/19/2020] [Indexed: 02/07/2023]
Abstract
Miro (mitochondrial Rho GTPases) a mitochondrial outer membrane protein, plays a vital role in the microtubule-based mitochondrial axonal transport, mitochondrial dynamics (fusion and fission) and Mito-Ca2+ homeostasis. It forms a major protein complex with Milton (an adaptor protein), kinesin and dynein (motor proteins), and facilitates bidirectional mitochondrial axonal transport such as anterograde and retrograde transport. By forming this protein complex, Miro facilitates the mitochondrial axonal transport and fulfills the neuronal energy demand, maintain the mitochondrial homeostasis and neuronal survival. It has been demonstrated that altered mitochondrial biogenesis, improper mitochondrial axonal transport, and mitochondrial dynamics are the early pathologies associated with most of the neurodegenerative diseases (NDs). Being the sole mitochondrial outer membrane protein associated with mitochondrial axonal transport-related processes, Miro proteins can be one of the key players in various NDs such as Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD). Thus, in the current review, we have discussed the evolutionarily conserved Miro proteins and its role in the pathogenesis of the various NDs. From this, we indicated that Miro proteins may act as a potential target for a novel therapeutic intervention for the treatment of various NDs.
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Affiliation(s)
- Komal Panchal
- Genetics & Developmental Biology Laboratory, Department of Biological Sciences & Biotechnology, Institute of Advanced Research (IAR), Koba, Gandhinagar, Gujarat 382426, India
| | - Anand Krishna Tiwari
- Genetics & Developmental Biology Laboratory, Department of Biological Sciences & Biotechnology, Institute of Advanced Research (IAR), Koba, Gandhinagar, Gujarat 382426, India.
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60
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Metabolic tuning of inhibition regulates hippocampal neurogenesis in the adult brain. Proc Natl Acad Sci U S A 2020; 117:25818-25829. [PMID: 32973092 DOI: 10.1073/pnas.2006138117] [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] [Indexed: 12/12/2022] Open
Abstract
Hippocampus-engaged behaviors stimulate neurogenesis in the adult dentate gyrus by largely unknown means. To explore the underlying mechanisms, we used tetrode recording to analyze neuronal activity in the dentate gyrus of freely moving adult mice during hippocampus-engaged contextual exploration. We found that exploration induced an overall sustained increase in inhibitory neuron activity that was concomitant with decreased excitatory neuron activity. A mathematical model based on energy homeostasis in the dentate gyrus showed that enhanced inhibition and decreased excitation resulted in a similar increase in neurogenesis to that observed experimentally. To mechanistically investigate this sustained inhibitory regulation, we performed metabolomic and lipidomic profiling of the hippocampus during exploration. We found sustainably increased signaling of sphingosine-1-phosphate, a bioactive metabolite, during exploration. Furthermore, we found that sphingosine-1-phosphate signaling through its receptor 2 increased interneuron activity and thus mediated exploration-induced neurogenesis. Taken together, our findings point to a behavior-metabolism circuit pathway through which experience regulates adult hippocampal neurogenesis.
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61
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Thomas CW, Guillaumin MCC, McKillop LE, Achermann P, Vyazovskiy VV. Global sleep homeostasis reflects temporally and spatially integrated local cortical neuronal activity. eLife 2020; 9:e54148. [PMID: 32614324 PMCID: PMC7332296 DOI: 10.7554/elife.54148] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 06/19/2020] [Indexed: 12/16/2022] Open
Abstract
Sleep homeostasis manifests as a relative constancy of its daily amount and intensity. Theoretical descriptions define 'Process S', a variable with dynamics dependent on global sleep-wake history, and reflected in electroencephalogram (EEG) slow wave activity (SWA, 0.5-4 Hz) during sleep. The notion of sleep as a local, activity-dependent process suggests that activity history must be integrated to determine the dynamics of global Process S. Here, we developed novel mathematical models of Process S based on cortical activity recorded in freely behaving mice, describing local Process S as a function of the deviation of neuronal firing rates from a locally defined set-point, independent of global sleep-wake state. Averaging locally derived Processes S and their rate parameters yielded values resembling those obtained from EEG SWA and global vigilance states. We conclude that local Process S dynamics reflects neuronal activity integrated over time, and global Process S reflects local processes integrated over space.
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Affiliation(s)
- Christopher W Thomas
- Department of Physiology, Anatomy and Genetics, University of OxfordOxfordUnited Kingdom
| | | | - Laura E McKillop
- Department of Physiology, Anatomy and Genetics, University of OxfordOxfordUnited Kingdom
| | - Peter Achermann
- Institute of Pharmacology and Toxicology, University of ZurichZurichSwitzerland
- The KEY Institute for Brain-Mind Research, Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of PsychiatryZurichSwitzerland
| | - Vladyslav V Vyazovskiy
- Department of Physiology, Anatomy and Genetics, University of OxfordOxfordUnited Kingdom
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62
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Ghosh Dastidar S, Das Sharma S, Chakraborty S, Chattarji S, Bhattacharya A, Muddashetty RS. Distinct regulation of bioenergetics and translation by group I mGluR and NMDAR. EMBO Rep 2020; 21:e48037. [PMID: 32351028 PMCID: PMC7271334 DOI: 10.15252/embr.201948037] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/12/2020] [Accepted: 03/27/2020] [Indexed: 12/11/2022] Open
Abstract
Neuronal activity is responsible for the high energy consumption in the brain. However, the cellular mechanisms draining ATP upon the arrival of a stimulus are yet to be explored systematically at the post-synapse. Here, we provide evidence that a significant fraction of ATP is consumed upon glutamate stimulation to energize mGluR-induced protein synthesis. We find that both mGluR and NMDAR alter protein synthesis and ATP consumption with distinct kinetics at the synaptic-dendritic compartments. While mGluR activation leads to a rapid and sustained reduction in neuronal ATP levels, NMDAR activation has no immediate impact on the same. ATP consumption correlates inversely with the kinetics of protein synthesis for both receptors. We observe a persistent elevation in protein synthesis within 5 minutes of mGluR activation and a robust inhibition of the same within 2 minutes of NMDAR activation, assessed by the phosphorylation status of eEF2 and metabolic labeling. However, a delayed protein synthesis-dependent ATP expenditure ensues after 15 minutes of NMDAR stimulation. We identify a central role for AMPK in the correlation between protein synthesis and ATP consumption. AMPK is dephosphorylated and inhibited upon mGluR activation, while it is phosphorylated upon NMDAR activation. Perturbing AMPK activity disrupts receptor-specific modulations of eEF2 phosphorylation and protein synthesis. Our observations, therefore, demonstrate that the regulation of the AMPK-eEF2 signaling axis by glutamate receptors alters neuronal protein synthesis and bioenergetics.
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Affiliation(s)
- Sudhriti Ghosh Dastidar
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
- Manipal Academy of Higher EducationManipalIndia
| | - Shreya Das Sharma
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
- The University of Trans‐Disciplinary Health Sciences and TechnologyBangaloreIndia
| | - Sumita Chakraborty
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
| | - Sumantra Chattarji
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
- National Center for Biological SciencesBangaloreIndia
| | - Aditi Bhattacharya
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
| | - Ravi S Muddashetty
- Institute for Stem Cell Sciences and Regenerative MedicineBangaloreIndia
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