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Alonso M, Petit AC, Lledo PM. The impact of adult neurogenesis on affective functions: of mice and men. Mol Psychiatry 2024; 29:2527-2542. [PMID: 38499657 DOI: 10.1038/s41380-024-02504-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 02/22/2024] [Accepted: 02/27/2024] [Indexed: 03/20/2024]
Abstract
In most mammals, new neurons are not only produced during embryogenesis but also after birth. Soon after adult neurogenesis was discovered, the influence of recruiting new neurons on cognitive functions, especially on memory, was documented. Likewise, the late process of neuronal production also contributes to affective functions, but this outcome was recognized with more difficulty. This review covers hypes and hopes of discovering the influence of newly-generated neurons on brain circuits devoted to affective functions. If the possibility of integrating new neurons into the adult brain is a commonly accepted faculty in the realm of mammals, the reluctance is strong when it comes to translating this concept to humans. Compiling data suggest now that new neurons are derived not only from stem cells, but also from a population of neuroblasts displaying a protracted maturation and ready to be engaged in adult brain circuits, under specific signals. Here, we discuss the significance of recruiting new neurons in the adult brain circuits, specifically in the context of affective outcomes. We also discuss the fact that adult neurogenesis could be the ultimate cellular process that integrates elements from both the internal and external environment to adjust brain functions. While we must be critical and beware of the unreal promises that Science could generate sometimes, it is important to continue exploring the potential of neural recruitment in adult primates. Reporting adult neurogenesis in humankind contributes to a new vision of humans as mammals whose brain continues to develop throughout life. This peculiar faculty could one day become the target of treatment for mental health, cognitive disorders, and elderly-associated diseases. The vision of an adult brain which never stops integrating new neurons is a real game changer for designing new therapeutic interventions to treat mental disorders associated with substantial morbidity, mortality, and social costs.
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Affiliation(s)
- Mariana Alonso
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Perception and Action Unit, F-75015, Paris, France
| | - Anne-Cécile Petit
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Perception and Action Unit, F-75015, Paris, France
- Pôle Hospitalo-Universitaire Psychiatrie Paris 15, GHU Paris Psychiatry and Neurosciences, Hôpital Sainte-Anne, Paris, France
| | - Pierre-Marie Lledo
- Institut Pasteur, Université Paris Cité, CNRS UMR 3571, Perception and Action Unit, F-75015, Paris, France.
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2
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Plácido E, Koss DJ, Outeiro TF, Brocardo PS. Altered hippocampal doublecortin expression in Parkinson's disease. J Neurochem 2024; 168:1514-1526. [PMID: 38485468 DOI: 10.1111/jnc.16101] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 02/28/2024] [Accepted: 03/03/2024] [Indexed: 07/31/2024]
Abstract
Parkinson's disease (PD) is a complex neurodegenerative disorder characterized by motor and non-motor symptoms. Motor symptoms include bradykinesia, resting tremors, muscular rigidity, and postural instability, while non-motor symptoms include cognitive impairments, mood disturbances, sleep disturbances, autonomic dysfunction, and sensory abnormalities. Some of these symptoms may be influenced by the proper hippocampus functioning, including adult neurogenesis. Doublecortin (DCX) is a microtubule-associated protein that plays a pivotal role in the development and differentiation of migrating neurons. This study utilized postmortem human brain tissue of PD and age-matched control individuals to investigate DCX expression in the context of adult hippocampal neurogenesis. Our findings demonstrate a significant reduction in the number of DCX-expressing cells within the subgranular zone (SGZ), as well as a decrease in the nuclear area of these DCX-positive cells in postmortem brain tissue obtained from PD cases, suggesting an impairment in the adult hippocampal neurogenesis. Additionally, we found that the nuclear area of DCX-positive cells correlates with pH levels. In summary, we provide evidence supporting that the process of hippocampal adult neurogenesis is likely to be compromised in PD patients before cognitive dysfunction, shedding light on potential mechanisms contributing to the neuropsychiatric symptoms observed in affected individuals. Understanding these mechanisms may offer novel insights into the pathophysiology of PD and possible therapeutic avenues.
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Affiliation(s)
- Evelini Plácido
- Neuroscience Graduate Program, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - David J Koss
- Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle Upon Tyne, UK
- Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
| | - Tiago Fleming Outeiro
- Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle Upon Tyne, UK
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Göttingen, Germany
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Patricia S Brocardo
- Neuroscience Graduate Program, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
- Morphological Sciences Department, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil
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3
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Khalil MH. Environmental enrichment: a systematic review on the effect of a changing spatial complexity on hippocampal neurogenesis and plasticity in rodents, with considerations for translation to urban and built environments for humans. Front Neurosci 2024; 18:1368411. [PMID: 38919908 PMCID: PMC11196820 DOI: 10.3389/fnins.2024.1368411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 05/21/2024] [Indexed: 06/27/2024] Open
Abstract
Introduction Hippocampal neurogenesis is critical for improving learning, memory, and spatial navigation. Inhabiting and navigating spatial complexity is key to stimulating adult hippocampal neurogenesis (AHN) in rodents because they share similar hippocampal neuroplasticity characteristics with humans. AHN in humans has recently been found to persist until the tenth decade of life, but it declines with aging and is influenced by environmental enrichment. This systematic review investigated the impact of spatial complexity on neurogenesis and hippocampal plasticity in rodents, and discussed the translatability of these findings to human interventions. Methods Comprehensive searches were conducted on three databases in English: PubMed, Web of Science, and Scopus. All literature published until December 2023 was screened and assessed for eligibility. A total of 32 studies with original data were included, and the process is reported in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement and checklist. Results The studies evaluated various models of spatial complexity in rodents, including environmental enrichment, changes to in-cage elements, complex layouts, and navigational mazes featuring novelty and intermittent complexity. A regression equation was formulated to synthesize key factors influencing neurogenesis, such as duration, physical activity, frequency of changes, diversity of complexity, age, living space size, and temperature. Conclusion Findings underscore the cognitive benefits of spatial complexity interventions and inform future translational research from rodents to humans. Home-cage enrichment and models like the Hamlet complex maze and the Marlau cage offer insight into how architectural design and urban navigational complexity can impact neurogenesis in humans. In-space changing complexity, with and without physical activity, is effective for stimulating neurogenesis. While evidence on intermittent spatial complexity in humans is limited, data from the COVID-19 pandemic lockdowns provide preliminary evidence. Existing equations relating rodent and human ages may allow for the translation of enrichment protocol durations from rodents to humans.
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Lazarov O, Disouky A, Sanborn M, Mostafa M, Sabitha K, Schantz A, Kim N, Pawlowski S, Honer W, Bennett D, Zhou Y, Keene C, Maienschein-Cline M, Rehman J. A roadmap to human hippocampal neurogenesis in adulthood, aging and AD. RESEARCH SQUARE 2024:rs.3.rs-4469965. [PMID: 38854131 PMCID: PMC11160907 DOI: 10.21203/rs.3.rs-4469965/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
In the rodent, hippocampal neurogenesis plays critical roles in learning and memory1,2, is tightly regulated by inhibitory neurons3-7 and contributes to memory dysfunction in Alzheimer's disease (AD) mouse models8-10. In contrast, the mechanisms regulating neurogenesis in the adult human hippocampus, the dynamic shifts in the transcriptomic and epigenomic profiles in aging and AD and putative niche interactions within the cellular environment, remain largely unknown. Using single nuclei multi-omics of postmortem human hippocampi we map the molecular mechanisms of hippocampal neurogenesis across aging, cognitive decline, and AD neuropathology. Transcriptomic and epigenetic profiling of neural stem cells (NSCs), neuroblasts and immature neurons suggests that the earliest shift in the characteristics of neurogenesis takes place in NSCs in aging. Cognitive impairment was associated with changes in neuroblast profile. In AD, there was a widespread cessation of the transcription machinery in immature neurons, with robust downregulation of genes regulating ribosomal and mitochondrial function. Further, there was substantial loss of parvalbumin+ inhibitory neurons in the hippocampus in aging. The number of the rest of inhibitory neurons were reduced as a function of age and diagnosis. Notably, a similar system-level effect was observed between immature and inhibitory neurons in the transition from aging to AD, manifested by common molecular pathways that were ultimately lost in AD. The numbers of neuroblasts, immature and GABAergic neurons inversely correlated with extent of neuropathology. Using CellChat and NeuronChat, we inferred the ligands and receptors by which neurogenic cells communicate with their cellular environment. Loss of synaptic adhesion molecules and neurotransmitters, either sent or received by neurogenic cells, was observed in AD. Together, this study delineates the molecular mechanisms and dynamics of human neurogenesis, functional association with inhibitory neurons and a mechanism of hippocampal hyperexcitability in AD.
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Affiliation(s)
| | | | | | | | - K Sabitha
- The University of Illinois at Chicago
| | | | | | | | | | | | - Yi Zhou
- Institute of Neuroscience, Chinese Academy of Sciences
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Simard S, Matosin N, Mechawar N. Adult Hippocampal Neurogenesis in the Human Brain: Updates, Challenges, and Perspectives. Neuroscientist 2024:10738584241252581. [PMID: 38757781 DOI: 10.1177/10738584241252581] [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: 05/18/2024]
Abstract
The existence of neurogenesis in the adult human hippocampus has been under considerable debate within the past three decades due to the diverging conclusions originating mostly from immunohistochemistry studies. While some of these reports conclude that hippocampal neurogenesis in humans occurs throughout physiologic aging, others indicate that this phenomenon ends by early childhood. More recently, some groups have adopted next-generation sequencing technologies to characterize with more acuity the extent of this phenomenon in humans. Here, we review the current state of research on adult hippocampal neurogenesis in the human brain with an emphasis on the challenges and limitations of using immunohistochemistry and next-generation sequencing technologies for its study.
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Affiliation(s)
- Sophie Simard
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montréal, Canada
| | - Natalie Matosin
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Naguib Mechawar
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, McGill University, Montréal, Canada
- Department of Psychiatry, McGill University, Montréal, Canada
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6
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Lazarov O, Gupta M, Kumar P, Morrissey Z, Phan T. Memory circuits in dementia: The engram, hippocampal neurogenesis and Alzheimer's disease. Prog Neurobiol 2024; 236:102601. [PMID: 38570083 PMCID: PMC11221328 DOI: 10.1016/j.pneurobio.2024.102601] [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: 08/10/2023] [Revised: 03/20/2024] [Accepted: 03/22/2024] [Indexed: 04/05/2024]
Abstract
Here, we provide an in-depth consideration of our current understanding of engrams, spanning from molecular to network levels, and hippocampal neurogenesis, in health and Alzheimer's disease (AD). This review highlights novel findings in these emerging research fields and future research directions for novel therapeutic avenues for memory failure in dementia. Engrams, memory in AD, and hippocampal neurogenesis have each been extensively studied. The integration of these topics, however, has been relatively less deliberated, and is the focus of this review. We primarily focus on the dentate gyrus (DG) of the hippocampus, which is a key area of episodic memory formation. Episodic memory is significantly impaired in AD, and is also the site of adult hippocampal neurogenesis. Advancements in technology, especially opto- and chemogenetics, have made sophisticated manipulations of engram cells possible. Furthermore, innovative methods have emerged for monitoring neurons, even specific neuronal populations, in vivo while animals engage in tasks, such as calcium imaging. In vivo calcium imaging contributes to a more comprehensive understanding of engram cells. Critically, studies of the engram in the DG using these technologies have shown the important contribution of hippocampal neurogenesis for memory in both health and AD. Together, the discussion of these topics provides a holistic perspective that motivates questions for future research.
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Affiliation(s)
- Orly Lazarov
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA.
| | - Muskan Gupta
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Pavan Kumar
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Zachery Morrissey
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Trongha Phan
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
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7
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Feng X, Qi F, Huang Y, Zhang G, Deng W. Reduced Expression of CLEC4G in Neurons Is Associated with Alzheimer's Disease. Int J Mol Sci 2024; 25:4621. [PMID: 38731839 PMCID: PMC11083414 DOI: 10.3390/ijms25094621] [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: 03/10/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 05/13/2024] Open
Abstract
CLEC4G, a glycan-binding receptor, has previously been demonstrated to inhibit Aβ generation, yet its brain localization and functions in Alzheimer's disease (AD) are not clear. We explored the localization, function, and regulatory network of CLEC4G via experiments and analysis of RNA-seq databases. CLEC4G transcripts and proteins were identified in brain tissues, with the highest expression observed in neurons. Notably, AD was associated with reduced levels of CLEC4G transcripts. Bioinformatic analyses revealed interactions between CLEC4G and relevant genes such as BACE1, NPC1, PILRA, TYROBP, MGAT1, and MGAT3, all displaying a negative correlation trend. We further identified the upstream transcriptional regulators NR2F6 and XRCC4 for CLEC4G and confirmed a decrease in CLEC4G expression in APP/PS1 transgenic mice. This study highlights the role of CLEC4G in protecting against AD progression and the significance of CLEC4G for AD research and management.
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Affiliation(s)
- Xinwei Feng
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen 510631, China
| | - Fangfang Qi
- Department of Neurology, Mayo Clinic, Rochester, MN 55901, USA
- Department of Anatomy and Physiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Yuying Huang
- Department of Microbial and Biochemical Pharmacy, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Ge Zhang
- Department of Microbial and Biochemical Pharmacy, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Wenbin Deng
- School of Pharmaceutical Sciences (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen 510631, China
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8
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González-Arnay E, Pérez-Santos I, Jiménez-Sánchez L, Cid E, Gal B, de la Prida LM, Cavada C. Immunohistochemical field parcellation of the human hippocampus along its antero-posterior axis. Brain Struct Funct 2024; 229:359-385. [PMID: 38180568 PMCID: PMC10917878 DOI: 10.1007/s00429-023-02725-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 10/15/2023] [Indexed: 01/06/2024]
Abstract
The primate hippocampus includes the dentate gyrus, cornu ammonis (CA), and subiculum. CA is subdivided into four fields (CA1-CA3, plus CA3h/hilus of the dentate gyrus) with specific pyramidal cell morphology and connections. Work in non-human mammals has shown that hippocampal connectivity is precisely patterned both in the laminar and longitudinal axes. One of the main handicaps in the study of neuropathological semiology in the human hippocampus is the lack of clear laminar and longitudinal borders. The aim of this study was to explore a histochemical segmentation of the adult human hippocampus, integrating field (medio-lateral), laminar, and anteroposterior longitudinal patterning. We provide criteria for head-body-tail field and subfield parcellation of the human hippocampus based on immunodetection of Rabphilin3a (Rph3a), Purkinje-cell protein 4 (PCP4), Chromogranin A and Regulation of G protein signaling-14 (RGS-14). Notably, Rph3a and PCP4 allow to identify the border between CA3 and CA2, while Chromogranin A and RGS-14 give specific staining of CA2. We also provide novel histological data about the composition of human-specific regions of the anterior and posterior hippocampus. The data are given with stereotaxic coordinates along the longitudinal axis. This study provides novel insights for a detailed region-specific parcellation of the human hippocampus useful for human brain imaging and neuropathology.
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Affiliation(s)
- Emilio González-Arnay
- Department of Anatomy, Histology and Neuroscience, Universidad Autónoma de Madrid, Madrid, Spain
- Department of Basic Medical Science-Division of Human Anatomy, Universidad de La Laguna, Santa Cruz de Tenerife, Canary Islands, Spain
| | - Isabel Pérez-Santos
- Department of Anatomy, Histology and Neuroscience, Universidad Autónoma de Madrid, Madrid, Spain
| | - Lorena Jiménez-Sánchez
- Department of Anatomy, Histology and Neuroscience, Universidad Autónoma de Madrid, Madrid, Spain
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Elena Cid
- Instituto Cajal, CSIC, Madrid, Spain
| | - Beatriz Gal
- Instituto Cajal, CSIC, Madrid, Spain
- Universidad CEU-San Pablo, Madrid, Spain
| | | | - Carmen Cavada
- Department of Anatomy, Histology and Neuroscience, Universidad Autónoma de Madrid, Madrid, Spain.
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9
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Perez GA, Park KW, Lanza D, Cicardo J, Danish Uddin M, Jankowsky JL. Generation of a Dcx-CreER T2 knock-in mouse for genetic manipulation of newborn neurons. Genesis 2024; 62:e23584. [PMID: 38102875 PMCID: PMC11021165 DOI: 10.1002/dvg.23584] [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: 10/13/2023] [Revised: 11/19/2023] [Accepted: 11/29/2023] [Indexed: 12/17/2023]
Abstract
A wide variety of CreERT2 driver lines are available for genetic manipulation of adult-born neurons in the mouse brain. These tools have been instrumental in studying fate potential, migration, circuit integration, and morphology of the stem cells supporting lifelong neurogenesis. Despite a wealth of tools, genetic manipulation of adult-born neurons for circuit and behavioral studies has been limited by poor specificity of many driver lines targeting early progenitor cells and by the inaccessibility of lines selective for later stages of neuronal maturation. We sought to address these limitations by creating a new CreERT2 driver line targeted to the endogenous mouse doublecortin locus as a marker of fate-specified neuroblasts and immature neurons. Our new model places a T2A-CreERT2 cassette immediately downstream of the Dcx coding sequence on the X chromosome, allowing expression of both Dcx and CreERT2 proteins in the endogenous spatiotemporal pattern for this gene. We demonstrate that the new mouse line drives expression of a Cre-dependent reporter throughout the brain in neonatal mice and in known neurogenic niches of adult animals. The line has been deposited with the Jackson Laboratory and should provide an accessible tool for studies targeting fate-restricted neuronal precursors.
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Affiliation(s)
- Gabriella A. Perez
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
| | - Kyung-Won Park
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
| | - Denise Lanza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030
| | - Jenna Cicardo
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
| | - M. Danish Uddin
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
| | - Joanna L. Jankowsky
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
- Departments of Neurology, Neurosurgery, and Molecular and Cellular Biology, Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030
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10
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Loef D, Tendolkar I, van Eijndhoven PFP, Hoozemans JJM, Oudega ML, Rozemuller AJM, Lucassen PJ, Dols A, Dijkstra AA. Electroconvulsive therapy is associated with increased immunoreactivity of neuroplasticity markers in the hippocampus of depressed patients. Transl Psychiatry 2023; 13:355. [PMID: 37981649 PMCID: PMC10658169 DOI: 10.1038/s41398-023-02658-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 10/23/2023] [Accepted: 11/07/2023] [Indexed: 11/21/2023] Open
Abstract
Electroconvulsive therapy (ECT) is an effective therapy for depression, but its cellular effects on the human brain remain elusive. In rodents, electroconvulsive shocks increase proliferation and the expression of plasticity markers in the hippocampal dentate gyrus (DG), suggesting increased neurogenesis. Furthermore, MRI studies in depressed patients have demonstrated increases in DG volume after ECT, that were notably paralleled by a decrease in depressive mood scores. Whether ECT also triggers cellular plasticity, inflammation or possibly injury in the human hippocampus, was unknown. We here performed a first explorative, anatomical study on the human post-mortem hippocampus of a unique, well-documented cohort of bipolar or unipolar depressed patients, who had received ECT in the 5 years prior to their death. They were compared to age-matched patients with a depressive disorder who had not received ECT and to matched healthy controls. Upon histopathological examination, no indications were observed for major hippocampal cell loss, overt cytoarchitectural changes or classic neuropathology in these 3 groups, nor were obvious differences present in inflammatory markers for astrocytes or microglia. Whereas the numbers of proliferating cells expressing Ki-67 was not different, we found a significantly higher percentage of cells positive for Doublecortin, a marker commonly used for young neurons and cellular plasticity, in the subgranular zone and CA4 / hilus of the hippocampus of ECT patients. Also, the percentage of positive Stathmin 1 cells was significantly higher in the subgranular zone of ECT patients, indicating neuroplasticity. These first post-mortem observations suggest that ECT has no damaging effects but may rather have induced neuroplasticity in the DG of depressed patients.
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Affiliation(s)
- Dore Loef
- Amsterdam UMC, location VUmc, Amsterdam, Department of Psychiatry, Amsterdam Neuroscience, Amsterdam, the Netherlands.
- GGZ inGeest Specialized Mental Health Care, Amsterdam, the Netherlands.
| | - Indira Tendolkar
- Department of Psychiatry, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behavior, Centre for Cognitive Neuroimaging, Nijmegen, the Netherlands
- Department of Psychiatry and Psychotherapy, University Hospital Essen, Essen, Germany
| | - Philip F P van Eijndhoven
- Department of Psychiatry, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behavior, Centre for Cognitive Neuroimaging, Nijmegen, the Netherlands
| | - Jeroen J M Hoozemans
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, the Netherlands
| | - Mardien L Oudega
- Amsterdam UMC, location VUmc, Amsterdam, Department of Psychiatry, Amsterdam Neuroscience, Amsterdam, the Netherlands
- GGZ inGeest Specialized Mental Health Care, Amsterdam, the Netherlands
| | - Annemieke J M Rozemuller
- Department of Pathology, Amsterdam Neuroscience, Amsterdam University Medical Centre, Amsterdam, the Netherlands
| | - Paul J Lucassen
- Brain Plasticity Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands
| | - Annemiek Dols
- Amsterdam UMC, location VUmc, Amsterdam, Department of Psychiatry, Amsterdam Neuroscience, Amsterdam, the Netherlands
- Department of Psychiatry, UMC Utrecht Brain Center, University Utrecht, Utrecht, the Netherlands
| | - Anke A Dijkstra
- Molecular Neuroscience Group, Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands
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11
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Stone J, Mitrofanis J, Johnstone DM, Robinson SR. Twelve protections evolved for the brain, and their roles in extending its functional life. Front Neuroanat 2023; 17:1280275. [PMID: 38020212 PMCID: PMC10657866 DOI: 10.3389/fnana.2023.1280275] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
As human longevity has increased, we have come to understand the ability of the brain to function into advanced age, but also its vulnerability with age, apparent in the age-related dementias. Against that background of success and vulnerability, this essay reviews how the brain is protected by (by our count) 12 mechanisms, including: the cranium, a bony helmet; the hydraulic support given by the cerebrospinal fluid; the strategically located carotid body and sinus, which provide input to reflexes that protect the brain from blood-gas imbalance and extremes of blood pressure; the blood brain barrier, an essential sealing of cerebral vessels; the secretion of molecules such as haemopexin and (we argue) the peptide Aβ to detoxify haemoglobin, at sites of a bleed; autoregulation of the capillary bed, which stabilises metabolites in extracellular fluid; fuel storage in the brain, as glycogen; oxygen storage, in the haemoprotein neuroglobin; the generation of new neurones, in the adult, to replace cells lost; acquired resilience, the stress-induced strengthening of cell membranes and energy production found in all body tissues; and cognitive reserve, the ability of the brain to maintain function despite damage. Of these 12 protections, we identify 5 as unique to the brain, 3 as protections shared with all body tissues, and another 4 as protections shared with other tissues but specialised for the brain. These protections are a measure of the brain's vulnerability, of its need for protection. They have evolved, we argue, to maintain cognitive function, the ability of the brain to function despite damage that accumulates during life. Several can be tools in the hands of the individual, and of the medical health professional, for the lifelong care of our brains.
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Affiliation(s)
- Jonathan Stone
- Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia
| | - John Mitrofanis
- Grenoble and Institute of Ophthalmology, Fonds de Dotation Clinatec, Université Grenoble Alpes, University College London, London, United Kingdom
| | - Daniel M. Johnstone
- School of Biomedical Sciences and Pharmacy, University of Newcastle and School of Medical Sciences, The University of Sydney, Camperdown, NSW, Australia
| | - Stephen R. Robinson
- School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, Australia
- Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia
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12
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Gallardo-Caballero M, Rodríguez-Moreno CB, Álvarez-Méndez L, Terreros-Roncal J, Flor-García M, Moreno-Jiménez EP, Rábano A, Llorens-Martín M. Prolonged fixation and post-mortem delay impede the study of adult neurogenesis in mice. Commun Biol 2023; 6:978. [PMID: 37741930 PMCID: PMC10517969 DOI: 10.1038/s42003-023-05367-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 09/15/2023] [Indexed: 09/25/2023] Open
Abstract
Adult hippocampal neurogenesis (AHN) gives rise to new neurons throughout life. This phenomenon takes place in more than 120 mammalian species, including humans, yet its occurrence in the latter was questioned after one study proposed the putative absence of neurogenesis markers in the adult human hippocampus. In this regard, we showed that prolonged fixation impedes the visualization of Doublecortin+ immature neurons in this structure, whereas other authors have suggested that a dilated post-mortem delay (PMD) underlies these discrepancies. Nevertheless, the individual and/or additive contribution of fixation and the PMD to the detection (or lack thereof) of other AHN markers has not been studied to date. To address this pivotal question, we used a tightly controlled experimental design in mice, which allowed the dissection of the relative contribution of the aforementioned factors to the visualization of markers of individual AHN stages. Fixation time emerged as the most prominent factor globally impeding the study of this process in mice. Moreover, the visualization of other particularly sensitive epitopes was further prevented by prolonged PMD. These results are crucial to disambiguate current controversies related to the occurrence of AHN not only in humans but also in other mammalian species.
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Affiliation(s)
- M Gallardo-Caballero
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - C B Rodríguez-Moreno
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - L Álvarez-Méndez
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - J Terreros-Roncal
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - M Flor-García
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - E P Moreno-Jiménez
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | | | - M Llorens-Martín
- Department of Molecular Neuropathology, Centro de Biología Molecular "Severo Ochoa" (CBMSO), Spanish Research Council (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain.
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain.
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain.
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Thyroid Hormone Transporters MCT8 and OATP1C1 Are Expressed in Pyramidal Neurons and Interneurons in the Adult Motor Cortex of Human and Macaque Brain. Int J Mol Sci 2023; 24:ijms24043207. [PMID: 36834621 PMCID: PMC9965431 DOI: 10.3390/ijms24043207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/26/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
Monocarboxylate transporter 8 (MCT8) and organic anion transporter polypeptide 1C1 (OATP1C1) are thyroid hormone (TH) transmembrane transporters that play an important role in the availability of TH for neural cells, allowing their proper development and function. It is important to define which cortical cellular subpopulations express those transporters to explain why MCT8 and OATP1C1 deficiency in humans leads to dramatic alterations in the motor system. By means of immunohistochemistry and double/multiple labeling immunofluorescence in adult human and monkey motor cortices, we demonstrate the presence of both transporters in long-projection pyramidal neurons and in several types of short-projection GABAergic interneurons in both species, suggesting a critical position of these transporters for modulating the efferent motor system. MCT8 is present at the neurovascular unit, but OATP1C1 is only present in some of the large vessels. Both transporters are expressed in astrocytes. OATP1C1 was unexpectedly found, only in the human motor cortex, inside the Corpora amylacea complexes, aggregates linked to substance evacuation towards the subpial system. On the basis of our findings, we propose an etiopathogenic model that emphasizes these transporters' role in controlling excitatory/inhibitory motor cortex circuits in order to understand some of the severe motor disturbances observed in TH transporter deficiency syndromes.
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14
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Salta E, Lazarov O, Fitzsimons CP, Tanzi R, Lucassen PJ, Choi SH. Adult hippocampal neurogenesis in Alzheimer's disease: A roadmap to clinical relevance. Cell Stem Cell 2023; 30:120-136. [PMID: 36736288 PMCID: PMC10082636 DOI: 10.1016/j.stem.2023.01.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 02/05/2023]
Abstract
Adult hippocampal neurogenesis (AHN) drops sharply during early stages of Alzheimer's disease (AD), via unknown mechanisms, and correlates with cognitive status in AD patients. Understanding AHN regulation in AD could provide a framework for innovative pharmacological interventions. We here combine molecular, behavioral, and clinical data and critically discuss the multicellular complexity of the AHN niche in relation to AD pathophysiology. We further present a roadmap toward a better understanding of the role of AHN in AD by probing the promises and caveats of the latest technological advancements in the field and addressing the conceptual and methodological challenges ahead.
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Affiliation(s)
- Evgenia Salta
- Laboratory of Neurogenesis and Neurodegeneration, Netherlands Institute for Neuroscience, Meibergdreef 47, 1105 BA, Amsterdam, The Netherlands
| | - Orly Lazarov
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, 808 S Wood St., Chicago, IL 60612, USA
| | - Carlos P Fitzsimons
- Brain Plasticity group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Rudolph Tanzi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, McCance Center for Brain Health, 114 16th Street, Boston, MA 02129, USA.
| | - Paul J Lucassen
- Brain Plasticity group, Swammerdam Institute for Life Sciences, Faculty of Science, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands; Center for Urban Mental Health, University of Amsterdam, Kruislaan 404, 1098 SM, Amsterdam, The Netherlands.
| | - Se Hoon Choi
- Genetics and Aging Research Unit, MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, McCance Center for Brain Health, 114 16th Street, Boston, MA 02129, USA.
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15
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Inoue R, Ni X, Mori H. Blockade of D-serine signaling and adult hippocampal neurogenesis attenuates remote contextual fear memory following multiple memory retrievals in male mice. Front Neurosci 2023; 16:1030702. [PMID: 36685240 PMCID: PMC9845639 DOI: 10.3389/fnins.2022.1030702] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 12/06/2022] [Indexed: 01/06/2023] Open
Abstract
The retrieval of fear memories induces two opposing processes, reconsolidation, and extinction. The memory reconsolidation is an active process that involves gene expression and updates an existing memory. It is hypothesized that blockade of reconsolidation by manipulating the neurobiological factors, which are mechanistically involved in the process, could weaken or disrupt the original fear memory. The N-methyl-D-aspartate (NMDA) receptor and hippocampal neurogenesis play crucial roles in hippocampus-dependent memory processes, including reconsolidation. Using contextual fear conditioning paradigm with multiple retrievals, we attempted to weaken the original contextual fear memory by repeatedly disrupting retrieval-induced reconsolidation via downregulation of NMDA receptor signaling and inhibition of neurogenesis. In the first experiment, prior to fear conditioning, NMDA receptor signaling was downregulated by the genetic reduction of its co-agonist, D-serine, and the neurogenesis was dampened by focal X-ray irradiation on the hippocampus. We found that simultaneous D-serine reduction and neurogenesis dampening resulted in a progressive decrease in freezing following each retrieval, leading to an attenuation of remote contextual fear memory on day 28. In the second experiment using the same behavioral protocols, after conditioning, pharmacological approaches were conducted to simultaneously block D-serine signaling and neurogenesis, resulting in a similar suppressive effect on the remote fear memory. The present findings provide insights for understanding the role of D-serine-mediated NMDA receptor signaling and neurogenesis in memory retrieval and the maintenance of remote fear memory, and improving the efficacy of exposure-based therapy for the treatment of post-traumatic stress disorder (PTSD).
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Affiliation(s)
- Ran Inoue
- Department of Molecular Neuroscience, Faculty of Medicine, University of Toyama, Toyama, Japan,Research Center for Idling Brain Science, University of Toyama, Toyama, Japan
| | - Xiance Ni
- Department of Molecular Neuroscience, Faculty of Medicine, University of Toyama, Toyama, Japan,Graduate School of Innovative Life Science, University of Toyama, Toyama, Japan
| | - Hisashi Mori
- Department of Molecular Neuroscience, Faculty of Medicine, University of Toyama, Toyama, Japan,Research Center for Idling Brain Science, University of Toyama, Toyama, Japan,*Correspondence: Hisashi Mori,
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