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Hingorani S, Paniagua Soriano G, Sánchez Huertas C, Villalba Riquelme EM, López Mocholi E, Martínez Rojas B, Alastrué Agudo A, Dupraz S, Ferrer Montiel AV, Moreno Manzano V. Transplantation of dorsal root ganglia overexpressing the NaChBac sodium channel improves locomotion after complete SCI. Mol Ther 2024; 32:1739-1759. [PMID: 38556794 PMCID: PMC11184342 DOI: 10.1016/j.ymthe.2024.03.038] [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: 12/06/2023] [Revised: 02/21/2024] [Accepted: 03/28/2024] [Indexed: 04/02/2024] Open
Abstract
Spinal cord injury (SCI) is a debilitating condition currently lacking treatment. Severe SCI causes the loss of most supraspinal inputs and neuronal activity caudal to the injury, which, coupled with the limited endogenous capacity for spontaneous regeneration, can lead to complete functional loss even in anatomically incomplete lesions. We hypothesized that transplantation of mature dorsal root ganglia (DRGs) genetically modified to express the NaChBac sodium channel could serve as a therapeutic option for functionally complete SCI. We found that NaChBac expression increased the intrinsic excitability of DRG neurons and promoted cell survival and neurotrophic factor secretion in vitro. Transplantation of NaChBac-expressing dissociated DRGs improved voluntary locomotion 7 weeks after injury compared to control groups. Animals transplanted with NaChBac-expressing DRGs also possessed higher tubulin-positive neuronal fiber and myelin preservation, although serotonergic descending fibers remained unaffected. We observed early preservation of the corticospinal tract 14 days after injury and transplantation, which was lost 7 weeks after injury. Nevertheless, transplantation of NaChBac-expressing DRGs increased the neuronal excitatory input by an increased number of VGLUT2 contacts immediately caudal to the injury. Our work suggests that the transplantation of NaChBac-expressing dissociated DRGs can rescue significant motor function, retaining an excitatory neuronal relay activity immediately caudal to injury.
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Affiliation(s)
- Sonia Hingorani
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Guillem Paniagua Soriano
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Carlos Sánchez Huertas
- Development and Assembly of Bilateral Neural Circuits Laboratory, Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Miguel Hernández, Avenida Santiago Ramon y Cajal, s/n, 03550 Sant Joan d'Alacant, Alicante, Spain
| | - Eva María Villalba Riquelme
- Biochemistry and Molecular Biology Department, Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche-IDiBE, Avenida de la Universidad, s/n, Edificio Torregaitán, 03202 Elche, Alicante, Spain
| | - Eric López Mocholi
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Beatriz Martínez Rojas
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Ana Alastrué Agudo
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain
| | - Sebastián Dupraz
- Laboratory for Axonal Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
| | - Antonio Vicente Ferrer Montiel
- Biochemistry and Molecular Biology Department, Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche-IDiBE, Avenida de la Universidad, s/n, Edificio Torregaitán, 03202 Elche, Alicante, Spain
| | - Victoria Moreno Manzano
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, 46012 Valencia, Spain.
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Wright J, Bourke P. Markov Blankets and Mirror Symmetries-Free Energy Minimization and Mesocortical Anatomy. ENTROPY (BASEL, SWITZERLAND) 2024; 26:287. [PMID: 38667842 PMCID: PMC11049374 DOI: 10.3390/e26040287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 03/21/2024] [Accepted: 03/25/2024] [Indexed: 04/28/2024]
Abstract
A theoretical account of development in mesocortical anatomy is derived from the free energy principle, operating in a neural field with both Hebbian and anti-Hebbian neural plasticity. An elementary structural unit is proposed, in which synaptic connections at mesoscale are arranged in paired patterns with mirror symmetry. Exchanges of synaptic flux in each pattern form coupled spatial eigenmodes, and the line of mirror reflection between the paired patterns operates as a Markov blanket, so that prediction errors in exchanges between the pairs are minimized. The theoretical analysis is then compared to the outcomes from a biological model of neocortical development, in which neuron precursors are selected by apoptosis for cell body and synaptic connections maximizing synchrony and also minimizing axonal length. It is shown that this model results in patterns of connection with the anticipated mirror symmetries, at micro-, meso- and inter-arial scales, among lateral connections, and in cortical depth. This explains the spatial organization and functional significance of neuron response preferences, and is compatible with the structural form of both columnar and noncolumnar cortex. Multi-way interactions of mirrored representations can provide a preliminary anatomically realistic model of cortical information processing.
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Affiliation(s)
- James Wright
- Centre for Brain Research, and Department of Psychological Medicine, School of Medicine, University of Auckland, Auckland 1010, New Zealand
| | - Paul Bourke
- School of Social Sciences, Faculty of Arts, Business, Law and Education, University of Western Australia, Perth, WA 6009, Australia
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Wallace JL, Pollen AA. Human neuronal maturation comes of age: cellular mechanisms and species differences. Nat Rev Neurosci 2024; 25:7-29. [PMID: 37996703 DOI: 10.1038/s41583-023-00760-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2023] [Indexed: 11/25/2023]
Abstract
The delayed and prolonged postmitotic maturation of human neurons, compared with neurons from other species, may contribute to human-specific cognitive abilities and neurological disorders. Here we review the mechanisms of neuronal maturation, applying lessons from model systems to understand the specific features of protracted human cortical maturation and species differences. We cover cell-intrinsic features of neuronal maturation, including transcriptional, epigenetic and metabolic mechanisms, as well as cell-extrinsic features, including the roles of activity and synapses, the actions of glial cells and the contribution of the extracellular matrix. We discuss evidence for species differences in biochemical reaction rates, the proposed existence of an epigenetic maturation clock and the contributions of both general and modular mechanisms to species-specific maturation timing. Finally, we suggest approaches to measure, improve and accelerate the maturation of human neurons in culture, examine crosstalk and interactions among these different aspects of maturation and propose conceptual models to guide future studies.
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Affiliation(s)
- Jenelle L Wallace
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA.
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
| | - Alex A Pollen
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, CA, USA.
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA.
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4
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Gonda S, Köhler I, Haase A, Czubay K, Räk A, Riedel C, Wahle P. Optogenetic stimulation shapes dendritic trees of infragranular cortical pyramidal cells. Front Cell Neurosci 2023; 17:1212483. [PMID: 37587917 PMCID: PMC10427221 DOI: 10.3389/fncel.2023.1212483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 06/09/2023] [Indexed: 08/18/2023] Open
Abstract
Spontaneous or experimentally evoked activity can lead to changes in length and/or branching of neocortical pyramidal cell dendrites. For instance, an early postnatal overexpression of certain AMPA or kainate glutamate receptor subunits leads to larger amplitudes of depolarizing events driven by spontaneous activity, and this increases apical dendritic complexity. Whether stimulation frequency has a role is less clear. In this study, we report that the expression of channelrhodopsin2-eYFP was followed by a 5-day optogenetic stimulation from DIV 5-10 or 11-15 in organotypic cultures of rat visual cortex-evoked dendritic remodeling. Stimulation at 0.05 Hz, at a frequency range of spontaneous calcium oscillations known to occur in the early postnatal neocortex in vivo until eye opening, had no effect. Stimulation with 0.5 Hz, a frequency at which the cortex in vivo adopts after eye opening, unexpectedly caused shorter and somewhat less branched apical dendrites of infragranular pyramidal neurons. The outcome resembles the remodeling of corticothalamic and callosal projection neurons of layers VI and V, which in the adult have apical dendrites no longer terminating in layer I. Exposure to 2.5 Hz, a frequency not occurring naturally during the time windows, evoked dendritic damage. The results suggested that optogenetic stimulation at a biologically meaningful frequency for the selected developmental stage can influence dendrite growth, but contrary to expectation, the optogenetic stimulation decreased dendritic growth.
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5
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Favaro J, Colombo MA, Mikulan E, Sartori S, Nosadini M, Pelizza MF, Rosanova M, Sarasso S, Massimini M, Toldo I. The maturation of aperiodic EEG activity across development reveals a progressive differentiation of wakefulness from sleep. Neuroimage 2023:120264. [PMID: 37399931 DOI: 10.1016/j.neuroimage.2023.120264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/04/2023] [Accepted: 07/01/2023] [Indexed: 07/05/2023] Open
Abstract
During development, the brain undergoes radical structural and functional changes following a posterior-to-anterior gradient, associated with profound changes of cortical electrical activity during both wakefulness and sleep. However, a systematic assessment of the developmental effects on aperiodic EEG activity maturation across vigilance states is lacking, particularly regarding its topographical aspects. Here, in a population of 160 healthy infants, children and teenagers (from 2 to 17 years, 10 subjects for each year), we investigated the development of aperiodic EEG activity in wakefulness and sleep. Specifically, we parameterized the shape of the aperiodic background of the EEG Power Spectral Density (PSD) by means of the spectral exponent and offset; the exponent reflects the rate of exponential decay of power over increasing frequencies and the offset reflects an estimate of the y-intercept of the PSD. We found that sleep and development caused the EEG-PSD to rotate over opposite directions: during wakefulness the PSD showed a flatter decay and reduced offset over development, while during sleep it showed a steeper decay and a higher offset as sleep becomes deeper. During deep sleep (N2, N3) only the spectral offset decreased over age, indexing a broad-band voltage reduction. As a result, the difference between values in deep sleep and those in both light sleep (N1) and wakefulness increased with age, suggesting a progressive differentiation of wakefulness from sleep EEG activity, most prominent over the frontal regions, the latest to complete maturation. Notably, the broad-band spectral exponent values during deep sleep stages were entirely separated from wakefulness values, consistently across developmental ages and in line with previous findings in adults. Concerning topographical development, the location showing the steepest PSD decay and largest offset shifted from posterior to anterior regions with age. This shift, particularly evident during deep sleep, paralleled the migration of sleep slow wave activity and was consistent with neuroanatomical and cognitive development. Overall, aperiodic EEG activity distinguishes wakefulness from sleep regardless of age; while, during development, it reveals a postero-anterior topographical maturation and a progressive differentiation of wakefulness from sleep. Our study could help to interpret changes due to pathological conditions and may elucidate the neurophysiological processes underlying the development of wakefulness and sleep.
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Affiliation(s)
- Jacopo Favaro
- Pediatric Neurology and Neurophysiology Unit, Department of Women's and Children Health, University of Padua, 35128, Padua, Italy.
| | - Michele A Colombo
- Department of Clinical and Biomedical Sciences "L. Sacco", University of Milan, 20157, Milan, Italy.
| | - Ezequiel Mikulan
- Department of Clinical and Biomedical Sciences "L. Sacco", University of Milan, 20157, Milan, Italy
| | - Stefano Sartori
- Pediatric Neurology and Neurophysiology Unit, Department of Women's and Children Health, University of Padua, 35128, Padua, Italy; Neuroimmunology Group, Pediatric Research Institute "Città della Speranza", 35127, Padua, Italy; Department of Neuroscience, University of Padua, 35121, Padua, Italy
| | - Margherita Nosadini
- Pediatric Neurology and Neurophysiology Unit, Department of Women's and Children Health, University of Padua, 35128, Padua, Italy; Neuroimmunology Group, Pediatric Research Institute "Città della Speranza", 35127, Padua, Italy
| | - Maria Federica Pelizza
- Pediatric Neurology and Neurophysiology Unit, Department of Women's and Children Health, University of Padua, 35128, Padua, Italy
| | - Mario Rosanova
- Department of Clinical and Biomedical Sciences "L. Sacco", University of Milan, 20157, Milan, Italy
| | - Simone Sarasso
- Department of Clinical and Biomedical Sciences "L. Sacco", University of Milan, 20157, Milan, Italy
| | - Marcello Massimini
- Department of Clinical and Biomedical Sciences "L. Sacco", University of Milan, 20157, Milan, Italy; IRCCS, Fondazione Don Carlo Gnocchi Onlus, 20148, Milan, Italy.
| | - Irene Toldo
- Pediatric Neurology and Neurophysiology Unit, Department of Women's and Children Health, University of Padua, 35128, Padua, Italy
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Schroer J, Warm D, De Rosa F, Luhmann HJ, Sinning A. Activity-dependent regulation of the BAX/BCL-2 pathway protects cortical neurons from apoptotic death during early development. Cell Mol Life Sci 2023; 80:175. [PMID: 37269320 DOI: 10.1007/s00018-023-04824-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/05/2023]
Abstract
During early brain development, homeostatic removal of cortical neurons is crucial and requires multiple control mechanisms. We investigated in the cerebral cortex of mice whether the BAX/BCL-2 pathway, an important regulator of apoptosis, is part of this machinery and how electrical activity might serve as a set point of regulation. Activity is known to be a pro-survival factor; however, how this effect is translated into enhanced survival chances on a neuronal level is not fully understood. In this study, we show that caspase activity is highest at the neonatal stage, while developmental cell death peaks at the end of the first postnatal week. During the first postnatal week, upregulation of BAX is accompanied by downregulation of BCL-2 protein, resulting in a high BAX/BCL-2 ratio when neuronal death rates are high. In cultured neurons, pharmacological blockade of activity leads to an acute upregulation of Bax, while elevated activity results in a lasting increase of BCL-2 expression. Spontaneously active neurons not only exhibit lower Bax levels than inactive neurons but also show almost exclusively BCL-2 expression. Disinhibition of network activity prevents the death of neurons overexpressing activated CASP3. This neuroprotective effect is not the result of reduced caspase activity but is associated with a downregulation of the BAX/BCL-2 ratio. Notably, increasing neuronal activity has a similar, non-additive effect as the blockade of BAX. Conclusively, high electrical activity modulates BAX/BCL-2 expression and leads to higher tolerance to CASP3 activity, increases survival, and presumably promotes non-apoptotic CASP3 functions in developing neurons.
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Affiliation(s)
- Jonas Schroer
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, 55128, Mainz, Germany
| | - Davide Warm
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, 55128, Mainz, Germany
| | - Federico De Rosa
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, 55128, Mainz, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, 55128, Mainz, Germany
| | - Anne Sinning
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, 55128, Mainz, Germany.
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7
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Wright JJ, Bourke PD. The mesoanatomy of the cortex, minimization of free energy, and generative cognition. Front Comput Neurosci 2023; 17:1169772. [PMID: 37251599 PMCID: PMC10213520 DOI: 10.3389/fncom.2023.1169772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/10/2023] [Indexed: 05/31/2023] Open
Abstract
Capacity for generativity and unlimited association is the defining characteristic of sentience, and this capacity somehow arises from neuronal self-organization in the cortex. We have previously argued that, consistent with the free energy principle, cortical development is driven by synaptic and cellular selection maximizing synchrony, with effects manifesting in a wide range of features of mesoscopic cortical anatomy. Here, we further argue that in the postnatal stage, as more structured inputs reach the cortex, the same principles of self-organization continue to operate at multitudes of local cortical sites. The unitary ultra-small world structures that emerged antenatally can represent sequences of spatiotemporal images. Local shifts of presynapses from excitatory to inhibitory cells result in the local coupling of spatial eigenmodes and the development of Markov blankets, minimizing prediction errors in each unit's interactions with surrounding neurons. In response to the superposition of inputs exchanged between cortical areas, more complicated, potentially cognitive structures are competitively selected by the merging of units and the elimination of redundant connections that result from the minimization of variational free energy and the elimination of redundant degrees of freedom. The trajectory along which free energy is minimized is shaped by interaction with sensorimotor, limbic, and brainstem mechanisms, providing a basis for creative and unlimited associative learning.
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Affiliation(s)
- James Joseph Wright
- Centre for Brain Research, and Department of Psychological Medicine, School of Medicine, University of Auckland, Auckland, New Zealand
| | - Paul David Bourke
- School of Social Sciences, Faculty of Arts, Business, Law and Education, University of Western Australia, Perth, WA, Australia
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8
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Wright JJ, Bourke PD. Unification of free energy minimization, spatiotemporal energy, and dimension reduction models of V1 organization: Postnatal learning on an antenatal scaffold. Front Comput Neurosci 2022; 16:869268. [PMID: 36313813 PMCID: PMC9614369 DOI: 10.3389/fncom.2022.869268] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 09/27/2022] [Indexed: 11/23/2022] Open
Abstract
Developmental selection of neurons and synapses so as to maximize pulse synchrony has recently been used to explain antenatal cortical development. Consequences of the same selection process—an application of the Free Energy Principle—are here followed into the postnatal phase in V1, and the implications for cognitive function are considered. Structured inputs transformed via lag relay in superficial patch connections lead to the generation of circumferential synaptic connectivity superimposed upon the antenatal, radial, “like-to-like” connectivity surrounding each singularity. The spatiotemporal energy and dimension reduction models of cortical feature preferences are accounted for and unified within the expanded model, and relationships of orientation preference (OP), space frequency preference (SFP), and temporal frequency preference (TFP) are resolved. The emergent anatomy provides a basis for “active inference” that includes interpolative modification of synapses so as to anticipate future inputs, as well as learn directly from present stimuli. Neurodynamic properties are those of heteroclinic networks with coupled spatial eigenmodes.
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Affiliation(s)
- James Joseph Wright
- Centre for Brain Research, University of Auckland, Auckland, New Zealand
- Department of Psychological Medicine, School of Medicine, University of Auckland, Auckland, New Zealand
- *Correspondence: James Joseph Wright,
| | - Paul David Bourke
- Faculty of Arts, Business, Law and Education, School of Social Sciences, University of Western Australia, Perth, WA, Australia
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9
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Tabuena DR, Huynh R, Metcalf J, Richner T, Stroh A, Brunton BW, Moody WJ, Easton CR. Large-scale waves of activity in the neonatal mouse brain in vivo occur almost exclusively during sleep cycles. Dev Neurobiol 2022; 82:596-612. [PMID: 36250606 PMCID: PMC10166374 DOI: 10.1002/dneu.22901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 09/09/2022] [Accepted: 10/06/2022] [Indexed: 01/30/2023]
Abstract
Spontaneous electrical activity plays major roles in the development of cortical circuitry. This activity can occur highly localized regions or can propagate over the entire cortex. Both types of activity coexist during early development. To investigate how different forms of spontaneous activity might be temporally segregated, we used wide-field trans-cranial calcium imaging over an entire hemisphere in P1-P8 mouse pups. We found that spontaneous waves of activity that propagate to cover the majority of the cortex (large-scale waves; LSWs) are generated at the end of the first postnatal week, along with several other forms of more localized activity. We further found that LSWs are segregated into sleep cycles. In contrast, cortical activity during wake states is more spatially restricted and the few large-scale forms of activity that occur during wake can be distinguished from LSWs in sleep based on their initiation in the motor cortex and their correlation with body movements. This change in functional cortical circuitry to a state that is permissive for large-scale activity may temporally segregate different forms of activity during critical stages when activity-dependent circuit development occurs over many spatial scales. Our data also suggest that LSWs in early development may be a functional precursor to slow sleep waves in the adult, which play critical roles in memory consolidation and synaptic rescaling.
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Affiliation(s)
- Dennis R Tabuena
- Department of Biology, University of Washington, Seattle, Washington, USA.,Graduate Program in Neuroscience, University of Washington, Seattle, Washington, USA
| | - Randy Huynh
- Department of Biology, University of Washington, Seattle, Washington, USA
| | - Jenna Metcalf
- Department of Biology, University of Washington, Seattle, Washington, USA
| | - Thomas Richner
- Institute for Neuroengineering, University of Washington, Seattle, Washington, USA
| | - Albrecht Stroh
- Institute of Pathophysiology, University Medical Center Mainz, Mainz, Germany.,Leibniz Institute for Resilience Research, University Medical Center Mainz, Mainz, Germany
| | - Bingni W Brunton
- Department of Biology, University of Washington, Seattle, Washington, USA.,Institute for Neuroengineering, University of Washington, Seattle, Washington, USA
| | - William J Moody
- Department of Biology, University of Washington, Seattle, Washington, USA.,Institute for Neuroengineering, University of Washington, Seattle, Washington, USA
| | - Curtis R Easton
- Department of Biology, University of Washington, Seattle, Washington, USA
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Arjun McKinney A, Petrova R, Panagiotakos G. Calcium and activity-dependent signaling in the developing cerebral cortex. Development 2022; 149:dev198853. [PMID: 36102617 PMCID: PMC9578689 DOI: 10.1242/dev.198853] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Calcium influx can be stimulated by various intra- and extracellular signals to set coordinated gene expression programs into motion. As such, the precise regulation of intracellular calcium represents a nexus between environmental cues and intrinsic genetic programs. Mounting genetic evidence points to a role for the deregulation of intracellular calcium signaling in neuropsychiatric disorders of developmental origin. These findings have prompted renewed enthusiasm for understanding the roles of calcium during normal and dysfunctional prenatal development. In this Review, we describe the fundamental mechanisms through which calcium is spatiotemporally regulated and directs early neurodevelopmental events. We also discuss unanswered questions about intracellular calcium regulation during the emergence of neurodevelopmental disease, and provide evidence that disruption of cell-specific calcium homeostasis and/or redeployment of developmental calcium signaling mechanisms may contribute to adult neurological disorders. We propose that understanding the normal developmental events that build the nervous system will rely on gaining insights into cell type-specific calcium signaling mechanisms. Such an understanding will enable therapeutic strategies targeting calcium-dependent mechanisms to mitigate disease.
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Affiliation(s)
- Arpana Arjun McKinney
- Graduate Program in Developmental and Stem Cell Biology, University of California, San Francisco, CA 94143, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA 94143, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA 94143, USA
| | - Ralitsa Petrova
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA 94143, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA 94143, USA
| | - Georgia Panagiotakos
- Graduate Program in Developmental and Stem Cell Biology, University of California, San Francisco, CA 94143, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, CA 94143, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA 94143, USA
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11
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Warm D, Bassetti D, Schroer J, Luhmann HJ, Sinning A. Spontaneous Activity Predicts Survival of Developing Cortical Neurons. Front Cell Dev Biol 2022; 10:937761. [PMID: 36035995 PMCID: PMC9399774 DOI: 10.3389/fcell.2022.937761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Spontaneous activity plays a crucial role in brain development by coordinating the integration of immature neurons into emerging cortical networks. High levels and complex patterns of spontaneous activity are generally associated with low rates of apoptosis in the cortex. However, whether spontaneous activity patterns directly encode for survival of individual cortical neurons during development remains an open question. Here, we longitudinally investigated spontaneous activity and apoptosis in developing cortical cultures, combining extracellular electrophysiology with calcium imaging. These experiments demonstrated that the early occurrence of calcium transients was strongly linked to neuronal survival. Silent neurons exhibited a higher probability of cell death, whereas high frequency spiking and burst behavior were almost exclusively detected in surviving neurons. In local neuronal clusters, activity of neighboring neurons exerted a pro-survival effect, whereas on the functional level, networks with a high modular topology were associated with lower cell death rates. Using machine learning algorithms, cell fate of individual neurons was predictable through the integration of spontaneous activity features. Our results indicate that high frequency spiking activity constrains apoptosis in single neurons through sustained calcium rises and thereby consolidates networks in which a high modular topology is reached during early development.
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12
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Chromatin compaction precedes apoptosis in developing neurons. Commun Biol 2022; 5:797. [PMID: 35941180 PMCID: PMC9359995 DOI: 10.1038/s42003-022-03704-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 07/11/2022] [Indexed: 11/19/2022] Open
Abstract
While major changes in cellular morphology during apoptosis have been well described, the subcellular changes in nuclear architecture involved in this process remain poorly understood. Imaging of nucleosomes in cortical neurons in vitro before and during apoptosis revealed that chromatin compaction precedes the activation of caspase-3 and nucleus shrinkage. While this early chromatin compaction remained unaffected by pharmacological blockade of the final execution of apoptosis through caspase-3 inhibition, interfering with the chromatin dynamics by modulation of actomyosin activity prevented apoptosis, but resulted in necrotic-like cell death instead. With super-resolution imaging at different phases of apoptosis in vitro and in vivo, we demonstrate that chromatin compaction occurs progressively and can be classified into five stages. In conclusion, we show that compaction of chromatin in the neuronal nucleus precedes apoptosis execution. These early changes in chromatin structure critically affect apoptotic cell death and are not part of the final execution of the apoptotic process in developing cortical neurons. Single-molecule imaging in developing cortical neurons shows that chromatin compaction precedes apoptosis and is an essential part of it, but can be uncoupled from the following apoptotic process.
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13
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Pumo GM, Kitazawa T, Rijli FM. Epigenetic and Transcriptional Regulation of Spontaneous and Sensory Activity Dependent Programs During Neuronal Circuit Development. Front Neural Circuits 2022; 16:911023. [PMID: 35664458 PMCID: PMC9158562 DOI: 10.3389/fncir.2022.911023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 04/28/2022] [Indexed: 11/13/2022] Open
Abstract
Spontaneous activity generated before the onset of sensory transduction has a key role in wiring developing sensory circuits. From axonal targeting, to synapse formation and elimination, to the balanced integration of neurons into developing circuits, this type of activity is implicated in a variety of cellular processes. However, little is known about its molecular mechanisms of action, especially at the level of genome regulation. Conversely, sensory experience-dependent activity implements well-characterized transcriptional and epigenetic chromatin programs that underlie heterogeneous but specific genomic responses that shape both postnatal circuit development and neuroplasticity in the adult. In this review, we focus on our knowledge of the developmental processes regulated by spontaneous activity and the underlying transcriptional mechanisms. We also review novel findings on how chromatin regulates the specificity and developmental induction of the experience-dependent program, and speculate their relevance for our understanding of how spontaneous activity may act at the genomic level to instruct circuit assembly and prepare developing neurons for sensory-dependent connectivity refinement and processing.
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Affiliation(s)
- Gabriele M. Pumo
- Laboratory of Neurodevelopmental Epigenetics, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Department Biozentrum, University of Basel, Basel, Switzerland
| | - Taro Kitazawa
- Laboratory of Neurodevelopmental Epigenetics, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Filippo M. Rijli
- Laboratory of Neurodevelopmental Epigenetics, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- Department Biozentrum, University of Basel, Basel, Switzerland
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Warm D, Schroer J, Sinning A. Gabaergic Interneurons in Early Brain Development: Conducting and Orchestrated by Cortical Network Activity. Front Mol Neurosci 2022; 14:807969. [PMID: 35046773 PMCID: PMC8763242 DOI: 10.3389/fnmol.2021.807969] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/06/2021] [Indexed: 01/22/2023] Open
Abstract
Throughout early phases of brain development, the two main neural signaling mechanisms—excitation and inhibition—are dynamically sculpted in the neocortex to establish primary functions. Despite its relatively late formation and persistent developmental changes, the GABAergic system promotes the ordered shaping of neuronal circuits at the structural and functional levels. Within this frame, interneurons participate first in spontaneous and later in sensory-evoked activity patterns that precede cortical functions of the mature brain. Upon their subcortical generation, interneurons in the embryonic brain must first orderly migrate to and settle in respective target layers before they can actively engage in cortical network activity. During this process, changes at the molecular and synaptic level of interneurons allow not only their coordinated formation but also the pruning of connections as well as excitatory and inhibitory synapses. At the postsynaptic site, the shift of GABAergic signaling from an excitatory towards an inhibitory response is required to enable synchronization within cortical networks. Concomitantly, the progressive specification of different interneuron subtypes endows the neocortex with distinct local cortical circuits and region-specific modulation of neuronal firing. Finally, the apoptotic process further refines neuronal populations by constantly maintaining a controlled ratio of inhibitory and excitatory neurons. Interestingly, many of these fundamental and complex processes are influenced—if not directly controlled—by electrical activity. Interneurons on the subcellular, cellular, and network level are affected by high frequency patterns, such as spindle burst and gamma oscillations in rodents and delta brushes in humans. Conversely, the maturation of interneuron structure and function on each of these scales feeds back and contributes to the generation of cortical activity patterns that are essential for the proper peri- and postnatal development. Overall, a more precise description of the conducting role of interneurons in terms of how they contribute to specific activity patterns—as well as how specific activity patterns impinge on their maturation as orchestra members—will lead to a better understanding of the physiological and pathophysiological development and function of the nervous system.
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Wright JJ, Bourke PD. Combining inter-areal, mesoscopic, and neurodynamic models of cortical function: Response to Commentary on "The growth of cognition: Free energy minimization and the embryogenesis of cortical computation". Phys Life Rev 2021; 39:88-95. [PMID: 34393081 DOI: 10.1016/j.plrev.2021.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 10/20/2022]
Affiliation(s)
- J J Wright
- Centre for Brain Research, and Department of Psychological Medicine, School of Medicine, University of Auckland, Auckland, New Zealand.
| | - P D Bourke
- School of Social Sciences, Faculty of Arts, Business, Law and Education, University of Western Australia, Perth, Australia
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