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Shabani Z, Liu J, Su H. Vascular Dysfunctions Contribute to the Long-Term Cognitive Deficits Following COVID-19. BIOLOGY 2023; 12:1106. [PMID: 37626992 PMCID: PMC10451811 DOI: 10.3390/biology12081106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/31/2023] [Accepted: 08/03/2023] [Indexed: 08/27/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a single-stranded RNA virus and a member of the corona virus family, primarily affecting the upper respiratory system and the lungs. Like many other respiratory viruses, SARS-CoV-2 can spread to other organ systems. Apart from causing diarrhea, another very common but debilitating complication caused by SARS-CoV-2 is neurological symptoms and cognitive difficulties, which occur in up to two thirds of hospitalized COVID-19 patients and range from shortness of concentration and overall declined cognitive speed to executive or memory function impairment. Neuro-cognitive dysfunction and "brain fog" are frequently present in COVID-19 cases, which can last several months after the infection, leading to disruption of daily life. Cumulative evidence suggests that SARS-CoV-2 affects vasculature in the extra-pulmonary systems directly or indirectly, leading to impairment of endothelial function and even multi-organ damage. The post COVID-19 long-lasting neurocognitive impairments have not been studied fully and their underlying mechanism remains elusive. In this review, we summarize the current understanding of the effects of COVID-19 on vascular dysfunction and how vascular dysfunction leads to cognitive impairment in patients.
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Affiliation(s)
- Zahra Shabani
- Center for Cerebrovascular Research, University of California (San Francisco), San Francisco, CA 94131, USA;
- Department of Anesthesia and Perioperative Care, University of California (San Francisco), San Francisco, CA 94131, USA
| | - Jialing Liu
- Department of Neurosurgery, University of California (San Francisco), San Francisco, CA 94131, USA;
| | - Hua Su
- Center for Cerebrovascular Research, University of California (San Francisco), San Francisco, CA 94131, USA;
- Department of Anesthesia and Perioperative Care, University of California (San Francisco), San Francisco, CA 94131, USA
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The Dialogue Between Neuroinflammation and Adult Neurogenesis: Mechanisms Involved and Alterations in Neurological Diseases. Mol Neurobiol 2023; 60:923-959. [PMID: 36383328 DOI: 10.1007/s12035-022-03102-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 10/23/2022] [Indexed: 11/18/2022]
Abstract
Adult neurogenesis occurs mainly in the subgranular zone of the hippocampal dentate gyrus and the subventricular zone of the lateral ventricles. Evidence supports the critical role of adult neurogenesis in various conditions, including cognitive dysfunction, Alzheimer's disease (AD), and Parkinson's disease (PD). Several factors can alter adult neurogenesis, including genetic, epigenetic, age, physical activity, diet, sleep status, sex hormones, and central nervous system (CNS) disorders, exerting either pro-neurogenic or anti-neurogenic effects. Compelling evidence suggests that any insult or injury to the CNS, such as traumatic brain injury (TBI), infectious diseases, or neurodegenerative disorders, can provoke an inflammatory response in the CNS. This inflammation could either promote or inhibit neurogenesis, depending on various factors, such as chronicity and severity of the inflammation and underlying neurological disorders. Notably, neuroinflammation, driven by different immune components such as activated glia, cytokines, chemokines, and reactive oxygen species, can regulate every step of adult neurogenesis, including cell proliferation, differentiation, migration, survival of newborn neurons, maturation, synaptogenesis, and neuritogenesis. Therefore, this review aims to present recent findings regarding the effects of various components of the immune system on adult neurogenesis and to provide a better understanding of the role of neuroinflammation and neurogenesis in the context of neurological disorders, including AD, PD, ischemic stroke (IS), seizure/epilepsy, TBI, sleep deprivation, cognitive impairment, and anxiety- and depressive-like behaviors. For each disorder, some of the most recent therapeutic candidates, such as curcumin, ginseng, astragaloside, boswellic acids, andrographolide, caffeine, royal jelly, estrogen, metformin, and minocycline, have been discussed based on the available preclinical and clinical evidence.
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Cellular, synaptic, and network effects of chemokines in the central nervous system and their implications to behavior. Pharmacol Rep 2021; 73:1595-1625. [PMID: 34498203 PMCID: PMC8599319 DOI: 10.1007/s43440-021-00323-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/15/2021] [Accepted: 08/16/2021] [Indexed: 02/07/2023]
Abstract
Accumulating evidence highlights chemokines as key mediators of the bidirectional crosstalk between neurons and glial cells aimed at preserving brain functioning. The multifaceted role of these immune proteins in the CNS is mirrored by the complexity of the mechanisms underlying its biological function, including biased signaling. Neurons, only in concert with glial cells, are essential players in the modulation of brain homeostatic functions. Yet, attempts to dissect these complex multilevel mechanisms underlying coordination are still lacking. Therefore, the purpose of this review is to summarize the current knowledge about mechanisms underlying chemokine regulation of neuron-glia crosstalk linking molecular, cellular, network, and behavioral levels. Following a brief description of molecular mechanisms by which chemokines interact with their receptors and then summarizing cellular patterns of chemokine expression in the CNS, we next delve into the sequence and mechanisms of chemokine-regulated neuron-glia communication in the context of neuroprotection. We then define the interactions with other neurotransmitters, neuromodulators, and gliotransmitters. Finally, we describe their fine-tuning on the network level and the behavioral relevance of their modulation. We believe that a better understanding of the sequence and nature of events that drive neuro-glial communication holds promise for the development of new treatment strategies that could, in a context- and time-dependent manner, modulate the action of specific chemokines to promote brain repair and reduce the neurological impairment.
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The microcephaly gene Donson is essential for progenitors of cortical glutamatergic and GABAergic neurons. PLoS Genet 2021; 17:e1009441. [PMID: 33739968 PMCID: PMC8011756 DOI: 10.1371/journal.pgen.1009441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 03/31/2021] [Accepted: 02/23/2021] [Indexed: 11/19/2022] Open
Abstract
Biallelic mutations in DONSON, an essential gene encoding for a replication fork protection factor, were linked to skeletal abnormalities and microcephaly. To better understand DONSON function in corticogenesis, we characterized Donson expression and consequences of conditional Donson deletion in the mouse telencephalon. Donson was widely expressed in the proliferation and differentiation zones of the embryonic dorsal and ventral telencephalon, which was followed by a postnatal expression decrease. Emx1-Cre-mediated Donson deletion in progenitors of cortical glutamatergic neurons caused extensive apoptosis in the early dorsomedial neuroepithelium, thus preventing formation of the neocortex and hippocampus. At the place of the missing lateral neocortex, these mutants exhibited a dorsal extension of an early-generated paleocortex. Targeting cortical neurons at the intermediate progenitor stage using Tbr2-Cre evoked no apparent malformations, whereas Nkx2.1-Cre-mediated Donson deletion in subpallial progenitors ablated 75% of Nkx2.1-derived cortical GABAergic neurons. Thus, the early telencephalic neuroepithelium depends critically on Donson function. Our findings help explain why the neocortex is most severely affected in individuals with DONSON mutations and suggest that DONSON-dependent microcephaly might be associated with so far unrecognized defects in cortical GABAergic neurons. Targeting Donson using an appropriate recombinase is proposed as a feasible strategy to ablate proliferating and nascent cells in experimental research. The cerebral cortex constitutes the largest part of the mammalian brain and is generated prenatally by highly proliferative progenitors. Genes encoding proteins that are essential for chromosomal segregation, mitotic division, DNA repair, and DNA damage response are frequently mutated in individuals diagnosed with microcephaly, a clinical condition characterized by cerebrocortical hypotrophy. Recent findings suggest that biallelic mutations in DONSON, a replication fork stabilization factor, cause microcephaly and skeletal defects, but this has not been formally tested. Here, we find that Cre-mediated Donson deletion in progenitors of cortical glutamatergic and cortical GABAergic neurons causes extensive programmed cell death at early stages of cortical development in mice. Cell death is induced in the proliferation zones and the postmitotic differentiation zones of the targeted progenitors. Mice undergoing Donson ablation in glutamatergic progenitors do not develop the hippocampus and dorsolateral neocortex, which leads to a dorsal shift of the early-generated piriform cortex. Donson deletion in GABAergic progenitors eliminates the vast majority of GABAergic neurons and oligodendrocyte precursors arising in the targeted lineage. We thus establish that Donson is essential for diverse early telencephalic progenitors. Targeting Donson might be used to kill off highly proliferating cells in experimental and probably therapeutic settings.
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Senf K, Karius J, Stumm R, Neuhaus EM. Chemokine signaling is required for homeostatic and injury-induced neurogenesis in the olfactory epithelium. Stem Cells 2021; 39:617-635. [PMID: 33470495 DOI: 10.1002/stem.3338] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/10/2020] [Indexed: 12/24/2022]
Abstract
The olfactory epithelium (OE) possesses unique lifelong neuroregenerative capacities and undergoes constitutive neurogenesis throughout mammalian lifespan. Two populations of stem cells, frequently dividing globose basal cells (GBCs) and quiescent horizontal basal cells (HBCs), readily replace olfactory neurons throughout lifetime. Although lineage commitment and neuronal differentiation of stem cells has already been described in terms of transcription factor expression, little is known about external factors balancing between differentiation and self-renewal. We show here that expression of the CXC-motif chemokine receptor 4 (CXCR4) distinguishes both types of stem cells. Extensive colocalization analysis revealed exclusive expression of CXCR4 in proliferating GBCs and their neuronal progenies. Moreover, only neuronal lineage cells were derived from CXCR4-CreER-tdTomato reporter mice in the OE. Furthermore, Cre-tdTomato mice specific for HBCs (Nestin+ and Cytokeratin14+) did not reduce CXCR4 expression when bred to mice bearing floxed CXCR4 alleles, and did not show labeling of the neuronal cells. CXCR4 and its ligand CXCL12 were markedly upregulated upon induction of GBC proliferation during injury-induced regeneration. in vivo overexpression of CXCL12 did downregulate CXCR4 levels, which results in reduced GBC maintenance and neuronal differentiation. We proved that these effects were caused by CXCR4 downregulation rather than over-activation by showing that the phenotypes of CXCL12-overexpressing mice were highly similar to the phenotypes of CXCR4 knockout mice. Our results demonstrate functional CXCR4 signaling in GBCs regulates cell cycle exit and neural differentiation. We propose that CXCR4/CXCL12 signaling is an essential regulator of olfactory neurogenesis and provide new insights into the dynamics of neurogenesis in the OE.
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Affiliation(s)
- Katja Senf
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Julia Karius
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Ralf Stumm
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Eva M Neuhaus
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
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Bobkova NV, Poltavtseva RA, Leonov SV, Sukhikh GT. Neuroregeneration: Regulation in Neurodegenerative Diseases and Aging. BIOCHEMISTRY (MOSCOW) 2020; 85:S108-S130. [PMID: 32087056 DOI: 10.1134/s0006297920140060] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
It had been commonly believed for a long time, that once established, degeneration of the central nervous system (CNS) is irreparable, and that adult person merely cannot restore dead or injured neurons. The existence of stem cells (SCs) in the mature brain, an organ with minimal regenerative ability, had been ignored for many years. Currently accepted that specific structures of the adult brain contain neural SCs (NSCs) that can self-renew and generate terminally differentiated brain cells, including neurons and glia. However, their contribution to the regulation of brain activity and brain regeneration in natural aging and pathology is still a subject of ongoing studies. Since the 1970s, when Fuad Lechin suggested the existence of repair mechanisms in the brain, new exhilarating data from scientists around the world have expanded our knowledge on the mechanisms implicated in the generation of various cell phenotypes supporting the brain, regulation of brain activity by these newly generated cells, and participation of SCs in brain homeostasis and regeneration. The prospects of the SC research are truthfully infinite and hitherto challenging to forecast. Once researchers resolve the issues regarding SC expansion and maintenance, the implementation of the SC-based platform could help to treat tissues and organs impaired or damaged in many devastating human diseases. Over the past 10 years, the number of studies on SCs has increased exponentially, and we have already become witnesses of crucial discoveries in SC biology. Comprehension of the mechanisms of neurogenesis regulation is essential for the development of new therapeutic approaches for currently incurable neurodegenerative diseases and neuroblastomas. In this review, we present the latest achievements in this fast-moving field and discuss essential aspects of NSC biology, including SC regulation by hormones, neurotransmitters, and transcription factors, along with the achievements of genetic and chemical reprogramming for the safe use of SCs in vitro and in vivo.
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Affiliation(s)
- N V Bobkova
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | - R A Poltavtseva
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia. .,National Medical Research Center for Obstetrics, Gynecology and Perinatology named after Academician V. I. Kulakov, Ministry of Healthcare of Russian Federation, Moscow, 117997, Russia
| | - S V Leonov
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia. .,Moscow Institute of Physics and Technology (National Research University), The Phystech School of Biological and Medical Physics, Dolgoprudny, Moscow Region, 141700, Russia
| | - G T Sukhikh
- National Medical Research Center for Obstetrics, Gynecology and Perinatology named after Academician V. I. Kulakov, Ministry of Healthcare of Russian Federation, Moscow, 117997, Russia.
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Epigenetic upregulation of hippocampal CXCL12 contributes to context spatial memory-associated morphine conditioning. Brain Behav Immun 2020; 84:72-79. [PMID: 31751616 DOI: 10.1016/j.bbi.2019.11.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 11/15/2019] [Accepted: 11/17/2019] [Indexed: 11/21/2022] Open
Abstract
Conditioned place preference (CPP) is a learned behavior, in which animals learn to associate environmental contexts with rewarding effects. The formation of CPP is an integrated outcome of multiple learning processes. Although multiple anatomical substrates underlying this contextual learning have been proposed, it remains unknown whether a specific molecular signaling pathway within CA1 mediates context learning associated with morphine conditioning. Here, we showed that repeated context learning associated with morphine conditioning significantly increased CXCL12 levels in hippocampal CA1 neurons, and the inhibition of CXCL12 expression ameliorated the CPP behavior following context exposure with morphine conditioning. Additionally, repeated context exposure with morphine conditioning increased the phosphorylation of STAT3 and the acetylation of histone H4 in CXCL12-expressing neurons in CA1. Immunoprecipitation and chromatin immunoprecipitation assays demonstrated that repeated context exposure with morphine conditioning increased the binding of STAT3 to the CXCL12 gene promoter and the interaction between STAT3 and p300, which contributed to the enhanced transcription of CXCL12 by increasing the acetylation of histone H4 in the CXCL12 gene promoter. The inhibition of STAT3 by intrathecal injection of S3I-201 suppressed the acetylation of histone H4. These data demonstrated the epigenetic upregulation of CXCL12 following repeated context exposure with morphine conditioning, which potentially contributed to the spatial memory consolidation associated with conditioned place preference induced by morphine conditioning.
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A Toolbox of Criteria for Distinguishing Cajal-Retzius Cells from Other Neuronal Types in the Postnatal Mouse Hippocampus. eNeuro 2020; 7:ENEURO.0516-19.2019. [PMID: 31907212 PMCID: PMC7004485 DOI: 10.1523/eneuro.0516-19.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 12/12/2019] [Indexed: 01/05/2023] Open
Abstract
The study of brain circuits depends on a clear understanding of the role played by different neuronal populations. Therefore, the unambiguous identification of different cell types is essential for the correct interpretation of experimental data. Here, we emphasize to the broader neuroscience community the importance of recognizing the persistent presence of Cajal-Retzius cells in the molecular layers of the postnatal hippocampus, and then we suggest a variety of criteria for distinguishing Cajal-Retzius cells from other neurons of the hippocampal molecular layers, such as GABAergic interneurons and semilunar granule cells. The toolbox of criteria that we have investigated (in male and female mice) can be useful both for anatomical and functional experiments, and relies on the quantitative study of neuronal somatic/nuclear morphology, location and developmental profile, expression of specific molecular markers (GAD67, reelin, COUP-TFII, calretinin, and p73), single cell anatomy, and electrophysiological properties. We conclude that Cajal-Retzius cells are small, non-GABAergic neurons that are tightly associated with the hippocampal fissure (HF), and that, within this area of interest, selectively express the proteins p73 and calretinin. We highlight the dangers of using markers such as reelin or COUP-TFII to identify Cajal-Retzius cells or GABAergic interneurons because of their poor specificity. Lastly, we examine neurons of the postnatal hippocampal molecular layers and show cell type-specific differences in their dendritic/axonal morphologies and density distributions, as well as in their membrane properties and spontaneous synaptic inputs. These parameters can be used to distinguish biocytin-filled and/or electrophysiologically recorded neurons and should be considered to avoid interpretational mistakes.
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Anstötz M, Lee SK, Neblett TI, Rune GM, Maccaferri G. Experience-Dependent Regulation of Cajal-Retzius Cell Networks in the Developing and Adult Mouse Hippocampus. ACTA ACUST UNITED AC 2019. [PMID: 28637318 DOI: 10.1093/cercor/bhx153] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In contrast to their near-disappearance in the adult neocortex, Cajal-Retzius cells have been suggested to persist longer in the hippocampus. A distinctive feature of the mature hippocampus, not maintained by other cortical areas, is its ability to sustain adult neurogenesis. Here, we have investigated whether environmental manipulations affecting hippocampal postnatal neurogenesis have a parallel impact on Cajal-Retzius cells. We used multiple mouse reporter lines to unequivocally identify Cajal-Retzius cells and quantify their densities during postnatal development. We found that exposure to an enriched environment increased the persistence of Cajal-Retzius cells in the hippocampus, but not in adjacent cortical regions. We did not observe a similar effect for parvalbumin-expressing interneurons, which suggested the occurrence of a cell type-specific process. In addition, we did not detect obvious changes either in Cajal-Retzius cell electrophysiological or morphological features, when compared with what previously reported in animals not exposed to enriched conditions. However, optogenetically triggered synaptic output of Cajal-Retzius cells onto local interneurons was enhanced, consistent with our observation of higher Cajal-Retzius cell densities. In conclusion, our data reveal a novel form of hippocampal, cell type-specific, experience-dependent network plasticity. We propose that this phenomenon may be involved in the regulation of enrichment-dependent enhanced hippocampal postnatal neurogenesis.
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Affiliation(s)
- Max Anstötz
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611-3008, USA.,Institute for Neuroanatomy, University/University Hospital Hamburg, 20246 Hamburg, Germany
| | - Sun Kyong Lee
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611-3008, USA
| | - Tamra I Neblett
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611-3008, USA
| | - Gabriele M Rune
- Institute for Neuroanatomy, University/University Hospital Hamburg, 20246 Hamburg, Germany
| | - Gianmaria Maccaferri
- Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611-3008, USA
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Smolders SMT, Kessels S, Vangansewinkel T, Rigo JM, Legendre P, Brône B. Microglia: Brain cells on the move. Prog Neurobiol 2019; 178:101612. [PMID: 30954517 DOI: 10.1016/j.pneurobio.2019.04.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/13/2019] [Accepted: 04/01/2019] [Indexed: 02/08/2023]
Abstract
In the last decade, tremendous progress has been made in understanding the biology of microglia - i.e. the fascinating immigrated resident immune cell population of the central nervous system (CNS). Recent literature reviews have largely dealt with the plentiful functions of microglia in CNS homeostasis, development and pathology, and the influences of sex and the microbiome. In this review, the intriguing aspect of their physical plasticity during CNS development will get specific attention. Microglia move around (mobility) and reshape their processes (motility). Microglial migration into and inside the CNS is most prominent throughout development and consequently most of the data described in this review concern mobility and motility in the changing environment of the developing brain. Here, we first define microglia based on their highly specialized age- and region-dependent gene expression signature and associated functional heterogeneity. Next, we describe their origin, the migration route of immature microglial cells towards the CNS, the mechanisms underlying their invasion of the CNS, and their spatiotemporal localization and surveying behaviour inside the developing CNS. These processes are dependent on microglial mobility and motility which are determined by the microenvironment of the CNS. Therefore, we further zoom in on the changing environment during CNS development. We elaborate on the extracellular matrix and the respective integrin receptors on microglia and we discuss the purinergic and molecular signalling in microglial mobility. In the last section, we discuss the physiological and pathological functions of microglia in which mobility and motility are involved to stress the importance of microglial 'movement'.
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Affiliation(s)
- Sophie Marie-Thérèse Smolders
- UHasselt, BIOMED, Diepenbeek, Belgium; INSERM, UMR-S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
| | | | | | | | - Pascal Legendre
- INSERM, UMR-S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UM CR18, Neuroscience Paris Seine, Paris, France
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Ganeshan V, Skladnev NV, Kim JY, Mitrofanis J, Stone J, Johnstone DM. Pre-conditioning with Remote Photobiomodulation Modulates the Brain Transcriptome and Protects Against MPTP Insult in Mice. Neuroscience 2019; 400:85-97. [PMID: 30625333 DOI: 10.1016/j.neuroscience.2018.12.050] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 12/18/2018] [Accepted: 12/30/2018] [Indexed: 12/14/2022]
Abstract
Transcranial photobiomodulation (PBM), which involves the application of low-intensity red to near-infrared light (600-1100 nm) to the head, provides neuroprotection in animal models of various neurodegenerative diseases. However, the absorption of light energy by the human scalp and skull may limit the utility of transcranial PBM in clinical contexts. We have previously shown that targeting light at peripheral tissues (i.e. "remote PBM") also provides protection of the brain in an MPTP mouse model of Parkinson's disease, suggesting remote PBM might be a viable alternative strategy for overcoming penetration issues associated with transcranial PBM. This present study aimed to determine an effective pre-conditioning regimen of remote PBM for inducing neuroprotection and elucidate the molecular mechanisms by which remote PBM enhances the resilience of brain tissue. Balb/c mice were irradiated with 670-nm light (4 J/cm2 per day) targeting dorsum and hindlimbs for 2, 5 or 10 days, followed by injection of the parkinsonian neurotoxin MPTP (50 mg/kg) over two consecutive days. Despite no direct irradiation of the head, 10 days of pre-conditioning with remote PBM significantly attenuated MPTP-induced loss of midbrain tyrosine hydroxylase-positive dopaminergic cells and mitigated the increase in FOS-positive neurons in the caudate-putamen complex. Interrogation of the midbrain transcriptome by RNA microarray and pathway enrichment analysis suggested upregulation of cell signaling and migration (including CXCR4+ stem cell and adipocytokine signaling), oxidative stress response pathways and modulation of the blood-brain barrier following remote PBM. These findings establish remote PBM preconditioning as a viable neuroprotective intervention and provide insights into the mechanisms underlying this phenomenon.
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Affiliation(s)
- Varshika Ganeshan
- Bosch Institute, University of Sydney, NSW 2006, Australia; Discipline of Physiology, University of Sydney, NSW 2006, Australia
| | - Nicholas V Skladnev
- Bosch Institute, University of Sydney, NSW 2006, Australia; Discipline of Physiology, University of Sydney, NSW 2006, Australia
| | - Ji Yeon Kim
- Bosch Institute, University of Sydney, NSW 2006, Australia; Discipline of Physiology, University of Sydney, NSW 2006, Australia; School of Medicine, University of Queensland Centre for Clinical Research, QLD 4029, Australia
| | - John Mitrofanis
- Bosch Institute, University of Sydney, NSW 2006, Australia; Discipline of Anatomy & Histology, University of Sydney, NSW 2006, Australia
| | - Jonathan Stone
- Bosch Institute, University of Sydney, NSW 2006, Australia; Discipline of Physiology, University of Sydney, NSW 2006, Australia
| | - Daniel M Johnstone
- Bosch Institute, University of Sydney, NSW 2006, Australia; Discipline of Physiology, University of Sydney, NSW 2006, Australia.
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12
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Ectopic neurogenesis induced by prenatal antiepileptic drug exposure augments seizure susceptibility in adult mice. Proc Natl Acad Sci U S A 2018; 115:4270-4275. [PMID: 29610328 PMCID: PMC5910824 DOI: 10.1073/pnas.1716479115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Recent clinical studies suggest that environmental insults, such as valproic acid (VPA) exposure, in utero can have adverse effects on brain function of the offspring in later life, although the underlying mechanisms of these impairments remain poorly understood. By focusing on the property of neural stem/progenitor cells (NS/PCs) residing in the adult hippocampus, we identified the mechanism of increased seizure sensitivity in prenatally VPA-exposed adult mice. Furthermore, we found that voluntary exercise can overcome the adverse effects through normalizing VPA-induced transcriptome alterations in NS/PCs. We believe that our study provides insights for further understanding and developing treatment strategies for neurological disorders induced by prenatal environmental insults. Epilepsy is a neurological disorder often associated with seizure that affects ∼0.7% of pregnant women. During pregnancy, most epileptic patients are prescribed antiepileptic drugs (AEDs) such as valproic acid (VPA) to control seizure activity. Here, we show that prenatal exposure to VPA in mice increases seizure susceptibility in adult offspring through mislocalization of newborn neurons in the hippocampus. We confirmed that neurons newly generated from neural stem/progenitor cells (NS/PCs) are integrated into the granular cell layer in the adult hippocampus; however, prenatal VPA treatment altered the expression in NS/PCs of genes associated with cell migration, including CXC motif chemokine receptor 4 (Cxcr4), consequently increasing the ectopic localization of newborn neurons in the hilus. We also found that voluntary exercise in a running wheel suppressed this ectopic neurogenesis and countered the enhanced seizure susceptibility caused by prenatal VPA exposure, probably by normalizing the VPA-disrupted expression of multiple genes including Cxcr4 in adult NS/PCs. Replenishing Cxcr4 expression alone in NS/PCs was sufficient to overcome the aberrant migration of newborn neurons and increased seizure susceptibility in VPA-exposed mice. Thus, prenatal exposure to an AED, VPA, has a long-term effect on the behavior of NS/PCs in offspring, but this effect can be counteracted by a simple physical activity. Our findings offer a step to developing strategies for managing detrimental effects in offspring exposed to VPA in utero.
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Abe P, Wüst HM, Arnold SJ, van de Pavert SA, Stumm R. CXCL12-mediated feedback from granule neurons regulates generation and positioning of new neurons in the dentate gyrus. Glia 2018. [PMID: 29537098 DOI: 10.1002/glia.23324] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Adult hippocampal neurogenesis is implicated in learning and memory processing. It is tightly controlled at several levels including progenitor proliferation as well as migration, differentiation and integration of new neurons. Hippocampal progenitors and immature neurons reside in the subgranular zone (SGZ) and are equipped with the CXCL12-receptor CXCR4 which contributes to defining the SGZ as neurogenic niche. The atypical CXCL12-receptor CXCR7 functions primarily by sequestering extracellular CXCL12 but whether CXCR7 is involved in adult neurogenesis has not been assessed. We report that granule neurons (GN) upregulate CXCL12 and CXCR7 during dentate gyrus maturation in the second postnatal week. To test whether GN-derived CXCL12 regulates neurogenesis and if neuronal CXCR7 receptors influence this process, we conditionally deleted Cxcl12 and Cxcr7 from the granule cell layer. Cxcl12 deletion resulted in lower numbers, increased dispersion and abnormal dendritic growth of immature GN and reduced neurogenesis. Cxcr7 ablation caused an increase in progenitor proliferation and progenitor numbers and reduced dispersion of immature GN. Thus, we provide a new mechanism where CXCL12-signals from GN prevent dispersion and support maturation of newborn GN. CXCR7 receptors of GN modulate the CXCL12-mediated feedback from GN to the neurogenic niche.
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Affiliation(s)
- Philipp Abe
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, 07747, Germany
| | - Hannah M Wüst
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, 07747, Germany
| | - Sebastian J Arnold
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Centre of Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Serge A van de Pavert
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, INSERM, CNRS, Marseille, France
| | - Ralf Stumm
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, 07747, Germany
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14
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Neural mechanisms underlying GABAergic regulation of adult hippocampal neurogenesis. Cell Tissue Res 2017; 371:33-46. [PMID: 28948349 DOI: 10.1007/s00441-017-2668-y] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 07/01/2017] [Indexed: 12/25/2022]
Abstract
Within the dentate gyrus of the adult hippocampus is the subgranular zone, which contains a neurogenic niche for radial-glia like cells, the most primitive neural stem cells in the adult brain. The quiescence of neural stem cells is maintained by tonic gamma-aminobutyric acid (GABA) released from local interneurons. Once these cells differentiate into neural progenitor cells, GABA continues to regulate their development into mature granule cells, the principal cell type of the dentate gyrus. Here, we review the role of GABA circuits, signaling, and receptors in regulating development of adult-born cells, as well as the molecular players that modulate GABA signaling. Furthermore, we review recent findings linking dysregulation of adult hippocampal neurogenesis to the altered GABAergic circuitry and signaling under various pathological conditions.
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15
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Dynamics and function of CXCR4 in formation of the granule cell layer during hippocampal development. Sci Rep 2017; 7:5647. [PMID: 28717168 PMCID: PMC5514042 DOI: 10.1038/s41598-017-05738-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 06/02/2017] [Indexed: 01/03/2023] Open
Abstract
In the developing hippocampus, granule cell progenitors (GCPs) arising in the ventricular zone (VZ) migrate to the subpial region, and form the granule cell layer (GCL) of the dentate gyrus (DG). To understand the mechanism of GCL formation, we investigated the dynamics and function of CXCR4 which is expressed by the GCPs and is a receptor of the CXCL12 chemokine secreted by cells surrounding the DG. In the VZ, CXCR4 was expressed on the plasma membrane of the GCPs. During their migration and in the DG, CXCR4 was internalized and accumulated as puncta close to the centrosomes, Golgi apparatus, and lysosomes. Phosphatase analysis suggested that both phosphorylated and dephosphorylated CXCR4 exist on the plasma membrane, whereas CXCR4 in intracellular puncta was mainly dephosphorylated. Intraventricular administration of the CXCR4 antagonist AMD3100 resulted in the disappearance of CXCR4 expression from the intracellular puncta, and its appearance on the plasma membranes. Furthermore, AMD3100 treatment resulted in precocious differentiation, delayed migration, and ectopic GCPs. Taken together, these results suggest that during the development and migration of GCPs, CXCR4 on the plasma membrane is phosphorylated, internalized, sorted to the centrosomes, Golgi apparatus, and lysosomes, and functionally regulates GCP differentiation, migration and positioning.
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16
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SDF-1/CXCR4 Signaling Maintains Stemness Signature in Mouse Neural Stem/Progenitor Cells. Stem Cells Int 2017; 2017:2493752. [PMID: 28408934 PMCID: PMC5376953 DOI: 10.1155/2017/2493752] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 01/29/2017] [Accepted: 02/01/2017] [Indexed: 11/17/2022] Open
Abstract
SDF-1 and its primary receptor, CXCR4, are highly expressed in the embryonic central nervous system (CNS) and play a crucial role in brain architecture. Loss of SDF-1/CXCR4 signaling causes abnormal development of neural stem/progenitor cells (NSCs/NPCs) in the cerebellum, hippocampus, and cortex. However, the mechanism of SDF-1/CXCR4 axis in NSCs/NPCs regulation remains unknown. In this study, we found that elimination of SDF-1/CXCR4 transduction caused NSCs/NPCs to lose their stemness characteristics and to encounter neurogenic differentiation. Moreover, Notch and RE1 silencing transcription factor (REST) both play an essential role in NSCs/NPCs maintenance and neuronal differentiation and were dramatically downregulated following SDF-1/CXCR4 cascade inhibition. Finally, we demonstrated that the expression of achaete-scute homolog 1 (Ascl1), a proneural gene, and p27, an antiproliferative gene, were significantly increased after genetic elimination of SDF-1 alleles. Our results support that the loss of functional SDF-1/CXCR4 signaling pathway in NSCs/NPCs induces exit of cell cycle and promotes premature neural differentiation.
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17
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Zhang L, Hua Q, Tang K, Shi C, Xie X, Zhang R. CXCR4 activation promotes differentiation of human embryonic stem cells to neural stem cells. Neuroscience 2016; 337:88-97. [DOI: 10.1016/j.neuroscience.2016.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 08/30/2016] [Accepted: 09/01/2016] [Indexed: 12/29/2022]
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18
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Zhao S, Qu H, Zhao Y, Xiao T, Zhao M, Li Y, Jolkkonen J, Cao Y, Zhao C. CXCR4 antagonist AMD3100 reverses the neurogenesis and behavioral recovery promoted by forced limb-use in stroke rats. Restor Neurol Neurosci 2016; 33:809-21. [PMID: 26444377 DOI: 10.3233/rnn-150515] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
PURPOSE Forced limb-use can enhance neurogenesis and behavioral recovery as well as increasing the level of stromal cell-derived factor-1 (SDF-1) in stroke rats. We examined whether the SDF-1/CXCR4 pathway is involved in the enhanced neurogenesis and promoted behavioral recovery induced by forced limb-use in the chronic phase of stroke. METHODS The CXCR4 antagonist, AMD3100, was used to block the SDF-1/CXCR4 pathway in the ischemic rats. Brain ischemia was induced by endothelin-1. One week after ischemia, the unimpaired forelimb of rats was immobilized for 3 weeks. The proliferation, migration, and survival of DCX-positive cells in the subventricular zone (SVZ), and the dendritic complexity of DCX-positive cells in the dentate gyrus (DG), as well as the inflammatory response in the infarcted striatum were analyzed by immunohistochemistry. Functional recovery was assessed in beam-walking and water maze tests. RESULTS Forced limb-use enhanced the proliferation, migration, dendritic complexity and the survival of newborn neurons. Furthermore, forced limb-use suppressed the inflammatory response and improved both motor and cognitive functions after stroke. AMD3100 significantly abrogated the enhanced neurogenesis and behavioral recovery induced by forced limb-use without influencing the inflammatory response. CONCLUSIONS SDF-1/CXCR4 pathway seems to be involved in the enhancement of neurogenesis and behavioral recovery induced by post-stroke forced limb-use.
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Affiliation(s)
- Shanshan Zhao
- Department of Neurology, The First Hospital of China Medical University, Shenyang, China
| | - Huiling Qu
- Department of Neurology, The First Hospital of China Medical University, Shenyang, China
| | - Yi Zhao
- Department of Obstetrics, The First Hospital of China Medical University, Shenyang, China
| | - Ting Xiao
- Department of Dermatology, The First Hospital of China Medical University, Shenyang, China.,Key Laboratory of Immunodermatology, Ministry of Health, Ministry of Education, Shenyang, China
| | - Mei Zhao
- Department of Cardiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yong Li
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jukka Jolkkonen
- Institute of Clinical Medicine - Neurology, University of Eastern Finland, Kuopio, Finland
| | - Yunpeng Cao
- Department of Neurology, The First Hospital of China Medical University, Shenyang, China
| | - Chuansheng Zhao
- Department of Neurology, The First Hospital of China Medical University, Shenyang, China
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19
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Ngalula KP, Cramer N, Schell MJ, Juliano SL. Transplanted Neural Progenitor Cells from Distinct Sources Migrate Differentially in an Organotypic Model of Brain Injury. Front Neurol 2015; 6:212. [PMID: 26500604 PMCID: PMC4595842 DOI: 10.3389/fneur.2015.00212] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/17/2015] [Indexed: 01/19/2023] Open
Abstract
Brain injury is a major cause of long-term disability. The possibility exists for exogenously derived neural progenitor cells to repair damage resulting from brain injury, although more information is needed to successfully implement this promising therapy. To test the ability of neural progenitor cells (NPCs) obtained from rats to repair damaged neocortex, we transplanted neural progenitor cell suspensions into normal and injured slice cultures of the neocortex acquired from rats on postnatal day 0–3. Donor cells from E16 embryos were obtained from either the neocortex, including the ventricular zone (VZ) for excitatory cells, ganglionic eminence (GE) for inhibitory cells or a mixed population of the two. Cells were injected into the ventricular/subventricular zone (VZ/SVZ) or directly into the wounded region. Transplanted cells migrated throughout the cortical plate with GE and mixed population donor cells predominately targeting the upper cortical layers, while neocortically derived NPCs from the VZ/SVZ migrated less extensively. In the injured neocortex, transplanted cells moved predominantly into the wounded area. NPCs derived from the GE tended to be immunoreactive for GABAergic markers while those derived from the neocortex were more strongly immunoreactive for other neuronal markers such as MAP2, TUJ1, or Milli-Mark. Cells transplanted in vitro acquired the electrophysiological characteristics of neurons, including action potential generation and reception of spontaneous synaptic activity. This suggests that transplanted cells differentiate into neurons capable of functionally integrating with the host tissue. Together, our data suggest that transplantation of neural progenitor cells holds great potential as an emerging therapeutic intervention for restoring function lost to brain damage.
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Affiliation(s)
- Kapinga P Ngalula
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of Health Sciences , Bethesda, MD , USA
| | - Nathan Cramer
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of Health Sciences , Bethesda, MD , USA
| | - Michael J Schell
- Department of Pharmacology, Uniformed Services University of Health Sciences , Bethesda, MD , USA
| | - Sharon L Juliano
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of Health Sciences , Bethesda, MD , USA
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20
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Coste C, Neirinckx V, Gothot A, Wislet S, Rogister B. Are neural crest stem cells the missing link between hematopoietic and neurogenic niches? Front Cell Neurosci 2015; 9:218. [PMID: 26136659 PMCID: PMC4469833 DOI: 10.3389/fncel.2015.00218] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 05/22/2015] [Indexed: 12/24/2022] Open
Abstract
Hematopoietic niches are defined as cellular and molecular microenvironments that regulate hematopoietic stem cell (HSC) function together with stem cell autonomous mechanisms. Many different cell types have been characterized as contributors to the formation of HSC niches, such as osteoblasts, endothelial cells, Schwann cells, and mesenchymal progenitors. These mesenchymal progenitors have themselves been classified as CXC chemokine ligand (CXCL) 12-abundant reticular (CAR) cells, stem cell factor expressing cells, or nestin-positive mesenchymal stem cells (MSCs), which have been recently identified as neural crest-derived cells (NCSCs). Together, these cells are spatially associated with HSCs and believed to provide appropriate microenvironments for HSC self-renewal, differentiation, mobilization and hibernation both by cell-cell contact and soluble factors. Interestingly, it appears that regulatory pathways governing the hematopoietic niche homeostasis are operating in the neurogenic niche as well. Therefore, this review paper aims to compare both the regulation of hematopoietic and neurogenic niches, in order to highlight the role of NCSCs and nervous system components in the development and the regulation of the hematopoietic system.
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Affiliation(s)
- Cécile Coste
- Groupe Interdisciplinaire de Génoprotéomique Appliquée-Neurosciences, Unit of Nervous System Disorders and Treatment, University of Liège Liège, Belgium
| | - Virginie Neirinckx
- Groupe Interdisciplinaire de Génoprotéomique Appliquée-Neurosciences, Unit of Nervous System Disorders and Treatment, University of Liège Liège, Belgium
| | - André Gothot
- Groupe Interdisciplinaire de Génoprotéomique Appliquée-Cardiovascular Sciences, University of Liège Liège, Belgium ; Hematology Department, University Hospital Liège, Belgium
| | - Sabine Wislet
- Groupe Interdisciplinaire de Génoprotéomique Appliquée-Neurosciences, Unit of Nervous System Disorders and Treatment, University of Liège Liège, Belgium
| | - Bernard Rogister
- Groupe Interdisciplinaire de Génoprotéomique Appliquée-Neurosciences, Unit of Nervous System Disorders and Treatment, University of Liège Liège, Belgium ; Groupe Interdisciplinaire de Génoprotéomique Appliquée-Development, Stem Cells and Regenerative Medicine, University of Liège Liège, Belgium ; Neurology Department, University Hospital Liège, Belgium
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21
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Banisadr G, Podojil JR, Miller SD, Miller RJ. Pattern of CXCR7 Gene Expression in Mouse Brain Under Normal and Inflammatory Conditions. J Neuroimmune Pharmacol 2015; 11:26-35. [PMID: 25997895 DOI: 10.1007/s11481-015-9616-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 05/06/2015] [Indexed: 12/20/2022]
Abstract
The chemokine stromal cell-derived factor-1 (SDF-1)/CXCL12 acting via its G-protein coupled receptor (GPCR) CXCR4 has been implicated in neurogenesis, neuromodulation, brain inflammation, HIV-1 encephalopathy and tumor growth. CXCR7 was identified as an alternate receptor for SDF-1/CXCL12. Characterization of CXCR7-deficient mice demonstrated a role for CXCR7 in fetal endothelial biology, cardiac development, and B-cell localization. Despite its ligand binding properties, CXCR7 does not seem to signal like a conventional GPCR. It has been suggested that CXCR7 may not function alone but in combination with CXCR4. Here, we investigated the regional localization of CXCR7 receptors in adult mouse brain using CXCR7-EGFP transgenic mice. We found that the receptors were expressed in various brain regions including olfactory bulb, cerebral cortex, hippocampus, subventricular zone (SVZ), hypothalamus and cerebellum. Extensive CXCR7 expression was associated with cerebral blood vessels. Using cell type specific markers, CXCR7 expression was found in neurons, astrocytes and oligodendrocyte progenitors. GAD-expressing neurons exhibited CXCR7 expression in the hippocampus. Expression of CXCR7 in the dentate gyrus included cells that expressed nestin, GFAP and cells that appeared to be immature granule cells. In mice with Experimental Autoimmune Encephalomyelitis (EAE), CXCR7 was expressed by migrating oligodendrocyte progenitors in the SVZ. We then compared the distribution of SDF-1/CXCL12 and CXCR7 using bitransgenic mice expressing both CXCR7-EGFP and SDF-1-mRFP. Enhanced expression of SDF-1/CXCL12 and CXCR7 was observed in the corpus callosum, SVZ and cerebellum. Overall, the expression of CXCR7 in normal and pathological nervous system suggests CXCR4-independent functions of SDF-1/CXCL12 mediated through its interaction with CXCR7.
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Affiliation(s)
- Ghazal Banisadr
- Department of Pharmacology, Northwestern University Medical School, 303 E Superior Ave, Chicago, IL, 60611, USA.
| | - Joseph R Podojil
- Department of Microbiology-Immunology, Northwestern University Medical School, 303 E Chicago Ave, Chicago, IL, 60611, USA
| | - Stephen D Miller
- Department of Microbiology-Immunology, Northwestern University Medical School, 303 E Chicago Ave, Chicago, IL, 60611, USA
| | - Richard J Miller
- Department of Pharmacology, Northwestern University Medical School, 303 E Superior Ave, Chicago, IL, 60611, USA
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22
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Optogenetic activation of cajal-retzius cells reveals their glutamatergic output and a novel feedforward circuit in the developing mouse hippocampus. J Neurosci 2014; 34:13018-32. [PMID: 25253849 DOI: 10.1523/jneurosci.1407-14.2014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cajal-Retzius cells orchestrate the development of cortical circuits by secreting the glycoprotein reelin. However, their computational functions are still unknown. In fact, the nature of their postsynaptic targets, major neurotransmitter released, as well as the class of postsynaptic receptors activated by their firing remain unclear. Here, we have addressed these questions by activating Cajal-Retzius cells optogenetically in mouse hippocampal slices. Light delivered to stratum lacunosum-moleculare triggered EPSCs both on local interneurons and on pyramidal cells. Responses recorded under voltage-clamp conditions had identical short latencies and similar amplitudes, but were kinetically different (i.e., faster in interneurons vs pyramidal cells). In both cases, responses were blocked by TTX, indicating that they were generated by action potential-dependent release. Responses in interneurons were rescued by the addition of 4-AP to TTX, and decreased when presynaptic firing in Cajal-Retzius cells was reduced by the chemokine CXCL12, indicating the existence of a direct Cajal-Retzius cell-interneuron monosynaptic connection. Although the combined application of 4-AP and TTX did not rescue responses in pyramidal cells, neither were they affected by the GABAA receptor blocker gabazine, which would be expected if they were polysynaptic. Both connections showed physiological and pharmacological properties indicating the involvement of AMPA- and NMDA-type glutamate receptors. The connectivity from presynaptic Cajal-Retzius cells to interneurons was strong enough to generate long-latency feedforward GABAergic input onto pyramidal cells. We propose that this newly defined Cajal-Retzius cell-dependent microcircuit may regulate synaptic plasticity and dendritic development in stratum lacunosum-moleculare, thus impacting the integrative properties of the developing hippocampus.
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23
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Guha SK, Tillu R, Sood A, Patgaonkar M, Nanavaty IN, Sengupta A, Sharma S, Vaidya VA, Pathak S. Single episode of mild murine malaria induces neuroinflammation, alters microglial profile, impairs adult neurogenesis, and causes deficits in social and anxiety-like behavior. Brain Behav Immun 2014; 42:123-37. [PMID: 24953429 DOI: 10.1016/j.bbi.2014.06.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 06/09/2014] [Accepted: 06/13/2014] [Indexed: 12/26/2022] Open
Abstract
Cerebral malaria is associated with cerebrovascular damage and neurological sequelae. However, the neurological consequences of uncomplicated malaria, the most prevalent form of the disease, remain uninvestigated. Here, using a mild malaria model, we show that a single Plasmodium chabaudi adami infection in adult mice induces neuroinflammation, neurogenic, and behavioral changes in the absence of a blood-brain barrier breach. Using cytokine arrays we show that the infection induces differential serum and brain cytokine profiles, both at peak parasitemia and 15days post-parasite clearance. At the peak of infection, along with the serum, the brain also exhibited a definitive pro-inflammatory cytokine profile, and gene expression analysis revealed that pro-inflammatory cytokines were also produced locally in the hippocampus, an adult neurogenic niche. Hippocampal microglia numbers were enhanced, and we noted a shift to an activated profile at this time point, accompanied by a striking redistribution of the microglia to the subgranular zone adjacent to hippocampal neuronal progenitors. In the hippocampus, a distinct decline in progenitor turnover and survival was observed at peak parasitemia, accompanied by a shift from neuronal to glial fate specification. Studies in transgenic Nestin-GFP reporter mice demonstrated a decline in the Nestin-GFP(+)/GFAP(+) quiescent neural stem cell pool at peak parasitemia. Although these cellular changes reverted to normal 15days post-parasite clearance, specific brain cytokines continued to exhibit dysregulation. Behavioral analysis revealed selective deficits in social and anxiety-like behaviors, with no change observed in locomotor, cognitive, and depression-like behaviors, with a return to baseline at recovery. Collectively, these findings indicate that even a single episode of mild malaria results in alterations of the brain cytokine profile, causes specific behavioral dysfunction, is accompanied by hippocampal microglial activation and redistribution, and a definitive, but transient, suppression of adult hippocampal neurogenesis.
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Affiliation(s)
- Suman K Guha
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Rucha Tillu
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Ankit Sood
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Mandar Patgaonkar
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Ishira N Nanavaty
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Arjun Sengupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Shobhona Sharma
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Vidita A Vaidya
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
| | - Sulabha Pathak
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
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24
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Stumm R. Somatostatin receptor sst2 reduces Akt activity and aggravates hypoxic/ischemic death in cerebral cortical neurons. Neuropharmacology 2014; 77:249-56. [DOI: 10.1016/j.neuropharm.2013.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/16/2013] [Accepted: 10/07/2013] [Indexed: 10/26/2022]
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25
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Schultheiß C, Abe P, Hoffmann F, Mueller W, Kreuder AE, Schütz D, Haege S, Redecker C, Keiner S, Kannan S, Claasen JH, Pfrieger FW, Stumm R. CXCR4 prevents dispersion of granule neuron precursors in the adult dentate gyrus. Hippocampus 2013; 23:1345-58. [PMID: 23929505 DOI: 10.1002/hipo.22180] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2013] [Indexed: 11/10/2022]
Abstract
Neurogenesis in the adult dentate gyrus (DG) generates new granule neurons that differentiate in the inner one-third of the granule cell layer (GCL). The migrating precursors of these neurons arise from neural stem cells (NSCs) in the subgranular zone (SGZ). Although it is established that pathological conditions, including epilepsy and stroke, cause dispersion of granule neuron precursors, little is known about the factors that regulate their normal placement. Based on the high expression of the chemokine CXCL12 in the adult GCL and its role in guiding neuronal migration in development, we addressed the function of the CXCL12 receptor CXCR4 in adult neurogenesis. Using transgenic reporter mice, we detected Cxcr4-GFP expression in NSCs, neuronal-committed progenitors, and immature neurons of adult and aged mice. Analyses of hippocampal NSC cultures and hippocampal tissue by immunoblot and immunohistochemistry provided evidence for CXCL12-promoted phosphorylation/activation of CXCR4 receptors in NSCs in vivo and in vitro. Cxcr4 deletion in NSCs of the postnatal or mature DG using Cre technology reduced neurogenesis. Fifty days after Cxcr4 ablation in the mature DG, the SGZ showed a severe reduction of Sox2-positive neural stem/early progenitor cells, NeuroD-positive neuronal-committed progenitors, and DCX-positive immature neurons. Many immature neurons were ectopically placed in the hilus and inner molecular layer, and some developed an aberrant dendritic morphology. Only few misplaced cells survived permanently as ectopic neurons. Thus, CXCR4 signaling maintains the NSC pool in the DG and specifies the inner one-third of the GCL as differentiation area for immature granule neurons.
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Affiliation(s)
- Clara Schultheiß
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
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26
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Mithal DS, Ren D, Miller RJ. CXCR4 signaling regulates radial glial morphology and cell fate during embryonic spinal cord development. Glia 2013; 61:1288-305. [PMID: 23828719 DOI: 10.1002/glia.22515] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 03/04/2013] [Accepted: 04/01/2013] [Indexed: 12/20/2022]
Abstract
Embryonic meninges secrete the chemokine SDF-1/CXCL12 as a chemotactic guide for migrating neural stem cells, but SDF-1 is not known to directly regulate the functions of radial glia. Recently, the developing meninges have been shown to regulate radial glial function, yet the mechanisms and signals responsible for this phenomenon remain unclear. Moreover, as a nonmigratory cell type, radial glia do not conform to traditional models associated with chemokine signaling in the central nervous system. Using fluorescent transgenes, in vivo genetic manipulations and pharmacological techniques, we demonstrate that SDF-1 derived from the meninges exerts a CXCR4-dependent effect on radial glia. Deletion of CXCR4 expression by radial glia influences their morphology, mitosis, and progression through both oligodendroglial and astroglial lineages. Additionally, disruption of CXCR4 signaling in radial glia has a transient effect on the migration of oligodendrocyte progenitors. These data indicate that a specific chemokine signal derived from the meninges has multiple regulatory effects on radial glia.
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Affiliation(s)
- Divakar S Mithal
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, 303 E Chicago Ave, Chicago, IL 60611, USA
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27
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Williamson LL, Bilbo SD. Chemokines and the hippocampus: a new perspective on hippocampal plasticity and vulnerability. Brain Behav Immun 2013; 30:186-94. [PMID: 23376170 DOI: 10.1016/j.bbi.2013.01.077] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 01/07/2013] [Accepted: 01/15/2013] [Indexed: 12/13/2022] Open
Abstract
The hippocampus is critical for several aspects of learning and memory and is unique among other cortical regions in structure, function and the potential for plasticity. This remarkable region recapitulates development throughout the lifespan with enduring neurogenesis and well-characterized plasticity. The structure and traits of the hippocampus that distinguish it from other brain regions, however, may be the same reasons that this important brain region is particularly vulnerable to insult and injury. The immune system within the brain responds to insult and injury, and the hippocampus and the immune system are extensively interconnected. Immune signaling molecules, cytokines and chemokines (chemotactic cytokines), are well known for their functions during insult or injury. They are also increasingly implicated in normal hippocampal neurogenesis (e.g., CXCR4 on newborn neurons), cellular plasticity (e.g., interleukin-6 in LTP maintenance), and learning and memory (e.g., interleukin-1β in fear conditioning). We provide evidence from the small but growing literature that neuroimmune interactions and immune signaling molecules, especially chemokines, may be a primary underlying mechanism for the coexistence of plasticity and vulnerability within the hippocampus. We also highlight the evidence that the hippocampus exhibits a remarkable resilience in response to diverse environmental events (e.g., enrichment, exercise), which all may converge onto common neuroimmune mechanisms.
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Affiliation(s)
- Lauren L Williamson
- Duke University, Genome Science Research Building 2, 210 Research Dr., Box 91050, Durham, NC 27710, United States.
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28
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Réaux-Le Goazigo A, Van Steenwinckel J, Rostène W, Mélik Parsadaniantz S. Current status of chemokines in the adult CNS. Prog Neurobiol 2013; 104:67-92. [PMID: 23454481 DOI: 10.1016/j.pneurobio.2013.02.001] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 02/01/2013] [Accepted: 02/03/2013] [Indexed: 12/13/2022]
Abstract
Chemokines - chemotactic cytokines - are small secreted proteins that attract and activate immune and non-immune cells in vitro and in vivo. It has been suggested that chemokines and their receptors play a role in the central nervous system (CNS), in addition to their well established role in the immune system. We focus here on three chemokines-CXCL12 (C-X-C motif ligand 12), CCL2 (C-C motif ligand 2), and CX3CL1 (C-X-3C motif ligand 1) - and their principal receptors - CXCR4 (C-X-C motif receptor 4), CCR2 (C-C motif receptor 2) and CX3CR1 (C-X-3C motif receptor 1), respectively. We first introduce the classification of chemokines and their G-protein coupled receptors and the main signaling pathways triggered by receptor activation. We then discuss the cellular distribution of CXCL12/CXCR4, CCL2/CCR2 and CX3CL1/CX3CR1 in adult brain and the neurotransmission and neuromodulation effects controlled by these chemokines in the adult CNS. Changes in the expression of CXCL12, CCL2 and CX3CL1 and their respective receptors are also increasingly being implicated in the pathogenesis of CNS disorders, such as Alzheimer's disease, Parkinson's disease, HIV-associated encephalopathy, stroke and multiple sclerosis, and are therefore plausible targets for future pharmacological intervention. The final section thus discusses the role of these chemokines in these pathophysiological states. In conclusion, the role of these chemokines in cellular communication may make it possible: (i) to identify new pathways of neuron-neuron, glia-glia or neuron-glia communications relevant to both normal brain function and neuroinflammatory and neurodegenerative diseases; (ii) to develop new therapeutic approaches for currently untreatable brain diseases.
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Abstract
Many tissues of the body cannot only repair themselves, but also self-renew, a property mainly due to stem cells and the various mechanisms that regulate their behavior. Stem cell biology is a relatively new field. While advances are slowly being realized, stem cells possess huge potential to ameliorate disease and counteract the aging process, causing its speculation as the next panacea. Amidst public pressure to advance rapidly to clinical trials, there is a need to understand the biology of stem cells and to support basic research programs. Without a proper comprehension of how cells and tissues are maintained during the adult life span, clinical trials are bound to fail. This review will cover the basic biology of stem cells, the various types of stem cells, their potential function, and the advantages and disadvantages to their use in medicine. We will next cover the role of G protein-coupled receptors in the regulation of stem cells and their potential in future clinical applications.
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Affiliation(s)
- VAN A. DOZE
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA (V.A.D.), and Department of Molecular Cardiology, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA (D.M.P.)
| | - DIANNE M. PEREZ
- Department of Pharmacology, Physiology and Therapeutics, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA (V.A.D.), and Department of Molecular Cardiology, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA (D.M.P.)
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30
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Choe Y, Pleasure SJ. Wnt signaling regulates intermediate precursor production in the postnatal dentate gyrus by regulating CXCR4 expression. Dev Neurosci 2012; 34:502-14. [PMID: 23257686 DOI: 10.1159/000345353] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 10/15/2012] [Indexed: 01/31/2023] Open
Abstract
Previous studies have examined the role of diverse signaling pathways in dentate neurogenesis, but how these signaling pathways are integrated remains unknown. Using mice that allow genetic manipulation of type 1 radial progenitors in the dentate, we show that forced induction of Wnt signaling leads to expansion of the intermediate progenitor cell (IPC) pool while selective activation of Sonic hedgehog (Shh) signaling drives neurogenesis without significant expansion of IPCs. Thus, both Wnt and Shh signaling are proneurogenic, but they act in distinct manners when their signaling is forced in subgranular zone radial progenitors. We examined potential targets of the Wnt pathway in these cells and found that Cxcr4 is a direct target of Lef1 in dentate gyrus progenitors and that loss of Cxcr4 in postnatal neurogenesis decreases the production of IPCs. This suggests that Wnt activation of dentate gyrus progenitors induces Cxcl12 signaling by regulating receptor expression. This study provides evidence that distinct morphogenic pathways have notably different roles in regulating ongoing dentate neurogenesis.
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Affiliation(s)
- Youngshik Choe
- Department of Neurology, Programs in University of California, San Francisco, CA 94158, USA
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31
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Fuentealba LC, Obernier K, Alvarez-Buylla A. Adult neural stem cells bridge their niche. Cell Stem Cell 2012; 10:698-708. [PMID: 22704510 DOI: 10.1016/j.stem.2012.05.012] [Citation(s) in RCA: 264] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Major developments in the neural stem cell (NSC) field in recent years provide new insights into the nature of the NSC niche. In this perspective, we integrate recent anatomical data on the organization of the two main neurogenic niches in the adult brain, the ventricular-subventricular zone (V-SVZ) and the subgranular zone (SGZ), with signaling pathways that control the behavior of NSCs. NSCs in the adult brain stretch into physiologically distinct compartments of their niche. We propose how adult NSCs' morphology may allow these cells to integrate multiple signaling pathways arising from unique locations of their niche.
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Affiliation(s)
- Luis C Fuentealba
- Department of Neurological Surgery and Institute for Regeneration Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Kirsten Obernier
- Department of Neurological Surgery and Institute for Regeneration Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Arturo Alvarez-Buylla
- Department of Neurological Surgery and Institute for Regeneration Medicine, University of California, San Francisco, San Francisco, CA 94143, USA.
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32
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Melnik A, Tauber S, Dumrese C, Ullrich O, Wolf SA. Murine adult neural progenitor cells alter their proliferative behavior and gene expression after the activation of Toll-like-receptor 3. Eur J Microbiol Immunol (Bp) 2012; 2:239-48. [PMID: 24688771 DOI: 10.1556/eujmi.2.2012.3.10] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 06/25/2012] [Indexed: 11/19/2022] Open
Abstract
Viral infections during pregnancy significantly increase the risk for psychological pathologies like schizophrenia in the offspring. One of the main morphological hallmarks of schizophrenia is a reduced size of the hippocampus. Since new neurons are produced in this particular brain compartment throughout life, it might be possible that low neurogenesis levels triggered by a maternal viral infection contribute to developmental deficits of the hippocampus. We injected polyinosinic:polycytidylic acid (Poly I:C) in pregnant C57Bl/6 mice to stimulate an anti-viral response through TLR3 and examined gene expressions in the neuronal progenitor cells (NPCs) of the offspring at different ages. Additionally, we treated adult NPC lines with Poly I:C to investigate its direct effect. We could show for the first time that TLR3 and its downstream effector molecule IRF3 are expressed in adult NPCs. Poly I:C treatment in vitro and in vivo led to the regulation of proliferation and genes involved in antiviral response, migration, and survival. These findings indicate that NPCs of the fetus are able to react towards an in utero immune response, and thus, changes in the neuronal stem cell pool can contribute to the development of neurological diseases like schizophrenia.
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33
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Zhu Y, Murakami F. Chemokine CXCL12 and its receptors in the developing central nervous system: emerging themes and future perspectives. Dev Neurobiol 2012; 72:1349-62. [PMID: 22689506 DOI: 10.1002/dneu.22041] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 05/25/2012] [Accepted: 06/01/2012] [Indexed: 01/24/2023]
Abstract
Homeostatic chemokine CXCL12 (also known as SDF-1) and its receptor CXCR4 are indispensable for the normal development of the nervous system. This chemokine system plays a plethora of functions in numerous neural developmental processes, from which the underlying molecular and cellular mechanisms are beginning to be unravelled. Recent identification of CXCR7 as a second receptor for CXCL12 provides opportunities to gain deeper insights into how CXCL12 operates in the nervous system. Here, we review the diverse roles of CXCL12 in the developing central nervous system, summarize the recent progress in uncovering CXCR7 functions, and discuss the emerging common themes from these works and future perspectives.
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Affiliation(s)
- Yan Zhu
- Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 1-3, Suita, Osaka 565-0871, Japan.
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34
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CXC chemokine receptor 7 (CXCR7) regulates CXCR4 protein expression and capillary tuft development in mouse kidney. PLoS One 2012; 7:e42814. [PMID: 22880115 PMCID: PMC3412803 DOI: 10.1371/journal.pone.0042814] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 07/12/2012] [Indexed: 02/07/2023] Open
Abstract
Background The CXCL12/CXCR4 axis is involved in kidney development by regulating formation of the glomerular tuft. Recently, a second CXCL12 receptor was identified and designated CXCR7. Although it is established that CXCR7 regulates heart and brain development in conjunction with CXCL12 and CXCR4, little is known about the influence of CXCR7 on CXCL12 dependent kidney development. Methodology/Principal Findings We provided analysis of CXCR7 expression and function in the developing mouse kidney. Using in situ hybridization, we identified CXCR7 mRNA in epithelial cells including podocytes at all nephron stages up to the mature glomerulus. CXCL12 mRNA showed a striking overlap with CXCR7 mRNA in epithelial structures. In addition, CXCL12 was detected in stromal cells and the glomerular tuft. Expression of CXCR4 was complementary to that of CXCR7 as it occurred in mesenchymal cells, outgrowing ureteric buds and glomerular endothelial cells but not in podocytes. Kidney examination in CXCR7 null mice revealed ballooning of glomerular capillaries as described earlier for CXCR4 null mice. Moreover, we detected a severe reduction of CXCR4 protein but not CXCR4 mRNA within the glomerular tuft and in the condensed mesenchyme. Malformation of the glomerular tuft in CXCR7 null mice was associated with mesangial cell clumping. Conclusions/Significance We established that there is a similar glomerular pathology in CXCR7 and CXCR4 null embryos. Based on the phenotype and the anatomical organization of the CXCL12/CXCR4/CXCR7 system in the forming glomerulus, we propose that CXCR7 fine-tunes CXCL12/CXCR4 mediated signalling between podocytes and glomerular capillaries.
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35
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Bilbo SD, Schwarz JM. The immune system and developmental programming of brain and behavior. Front Neuroendocrinol 2012; 33:267-86. [PMID: 22982535 PMCID: PMC3484177 DOI: 10.1016/j.yfrne.2012.08.006] [Citation(s) in RCA: 389] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 08/28/2012] [Accepted: 08/29/2012] [Indexed: 12/16/2022]
Abstract
The brain, endocrine, and immune systems are inextricably linked. Immune molecules have a powerful impact on neuroendocrine function, including hormone-behavior interactions, during health as well as sickness. Similarly, alterations in hormones, such as during stress, can powerfully impact immune function or reactivity. These functional shifts are evolved, adaptive responses that organize changes in behavior and mobilize immune resources, but can also lead to pathology or exacerbate disease if prolonged or exaggerated. The developing brain in particular is exquisitely sensitive to both endogenous and exogenous signals, and increasing evidence suggests the immune system has a critical role in brain development and associated behavioral outcomes for the life of the individual. Indeed, there are associations between many neuropsychiatric disorders and immune dysfunction, with a distinct etiology in neurodevelopment. The goal of this review is to describe the important role of the immune system during brain development, and to discuss some of the many ways in which immune activation during early brain development can affect the later-life outcomes of neural function, immune function, mood and cognition.
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Affiliation(s)
- Staci D Bilbo
- Department of Psychology and Neuroscience, Duke University, 572 Research Drive, Box 91050, Durham, NC 27708, USA.
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36
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Abstract
The importance of adult neurogenesis has only recently been accepted, resulting in a completely new field of investigation within stem cell biology. The regulation and functional significance of adult neurogenesis is currently an area of highly active research. G-protein-coupled receptors (GPCRs) have emerged as potential modulators of adult neurogenesis. GPCRs represent a class of proteins with significant clinical importance, because approximately 30% of all modern therapeutic treatments target these receptors. GPCRs bind to a large class of neurotransmitters and neuromodulators such as norepinephrine, dopamine, and serotonin. Besides their typical role in cellular communication, GPCRs are expressed on adult neural stem cells and their progenitors that relay specific signals to regulate the neurogenic process. This review summarizes the field of adult neurogenesis and its methods and specifies the roles of various GPCRs and their signal transduction pathways that are involved in the regulation of adult neural stem cells and their progenitors. Current evidence supporting adult neurogenesis as a model for self-repair in neuropathologic conditions, adult neural stem cell therapeutic strategies, and potential avenues for GPCR-based therapeutics are also discussed.
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Affiliation(s)
- Van A Doze
- Department of Molecular Cardiology, NB50, Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Ave., Cleveland, OH 44195, USA
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37
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Song J, Christian KM, Ming GL, Song H. Modification of hippocampal circuitry by adult neurogenesis. Dev Neurobiol 2012; 72:1032-43. [PMID: 22354697 PMCID: PMC3710549 DOI: 10.1002/dneu.22014] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The adult hippocampus is one of the primary neural structures involved in memory formation. In addition to synapse-specific modifications thought to encode information at the subcellular level, changes in the intrahippocampal neuro-populational activity and dynamics at the circuit-level may contribute substantively to the functional capacity of this region. Within the hippocampus, the dentate gyrus has the potential to make a preferential contribution to neural circuit modification owing to the continuous addition of new granule cell population. The integration of newborn neurons into pre-existing circuitry is hypothesized to deliver a unique processing capacity, as opposed to merely replacing dying granule cells. Recent studies have begun to assess the impact of hippocampal neurogenesis by examining the extent to which adult-born neurons participate in hippocampal networks, including when newborn neurons become engaged in ongoing network activity and how they modulate circuit dynamics via their unique intrinsic physiological properties. Understanding the contributions of adult neurogenesis to hippocampal function will provide new insight into the fundamental aspects of brain plasticity, which can be used to guide therapeutic interventions to replace neural populations damaged by disease or injury.
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Affiliation(s)
- Juan Song
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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38
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Kizil C, Kaslin J, Kroehne V, Brand M. Adult neurogenesis and brain regeneration in zebrafish. Dev Neurobiol 2012; 72:429-61. [DOI: 10.1002/dneu.20918] [Citation(s) in RCA: 249] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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39
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Mithal DS, Banisadr G, Miller RJ. CXCL12 signaling in the development of the nervous system. J Neuroimmune Pharmacol 2012; 7:820-34. [PMID: 22270883 DOI: 10.1007/s11481-011-9336-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 12/14/2011] [Indexed: 11/30/2022]
Abstract
Chemokines are small, secreted proteins that have been shown to be important regulators of leukocyte trafficking and inflammation. All the known effects of chemokines are transduced by action at a family of G protein coupled receptors. Two of these receptors, CCR5 and CXCR4, are also known to be the major cellular receptors for HIV-1. Consideration of the evolution of the chemokine family has demonstrated that the chemokine Stromal cell Derived Factor-1 or SDF1 (CXCL12) and its receptor CXCR4 are the most ancient members of the family and existed in animals prior to the development of a sophisticated immune system. Thus, it appears that the original function of chemokine signaling was in the regulation of stem cell trafficking and development. CXCR4 signaling is important in the development of many tissues including the nervous system. Here we discuss the manner in which CXCR4 signaling can regulate the development of different structures in the central and peripheral nervous systems and the different strategies employed to achieve these effects.
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Affiliation(s)
- Divakar S Mithal
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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40
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Shin JW, Lee JK, Lee JE, Min WK, Schuchman EH, Jin HK, Bae JS. Combined effects of hematopoietic progenitor cell mobilization from bone marrow by granulocyte colony stimulating factor and AMD3100 and chemotaxis into the brain using stromal cell-derived factor-1α in an Alzheimer's disease mouse model. Stem Cells 2011; 29:1075-89. [PMID: 21608078 DOI: 10.1002/stem.659] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Transplantation of bone marrow-derived stem cells (BMSCs) has been suggested as a potential therapeutic approach to prevent neurodegenerative diseases, but it remains problematic due to issues of engraftment, potential toxicities, and other factors. An alternative strategy is pharmacological-induced recruitment of endogenous BMSCs into an injured site by systemic administration of growth factors or chemokines. Therefore, the aim of this study was to examine the effects of therapy involving granulocyte colony stimulating factor (G-CSF)/AMD3100 (CXCR4 antagonist) and stromal cell-derived factor-1α (SDF-1α) on endogenous BM-derived hematopoietic progenitor cell (BM-HPC) recruitment into the brain of an Alzheimer's disease (AD) mouse model. To mobilize BM-HPCs, G-CSF was injected intraperitoneally and boosted by AMD3100. Simultaneously, these mice received an intracerebral injection with SDF-1α to induce migration of mobilized BM-HPCs into brain. We found that the memory deficit in the AD mice was significantly improved by these treatments, but amyloid β deposition was unchanged. Interestingly, microglial activation was increased with alternative activation of microglia to a neuroprotective phenotype. Furthermore, by generating an amyloid precursor protein/presenilin 1-green fluorescent protein (GFP) chimeric mouse, we ascertained that the GFP positive microglia identified in the brain were BM-derived. Additionally, increased hippocampal neurogenesis and improved memory was observed in mice receiving combined G-CSF/AMD3100 and SDF-1α, but not in controls or animals receiving each treatment alone. These results suggest that SDF-1α is an effective adjuvant in inducing migration into brain of the endogenous BM-HPCs, mobilized by G-CSF/AMD3100, and that the two can act synergistically to produce a therapeutic effect. This approach warrants further investigation as a potential therapeutic option for the treatment of AD patients in the future.
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Affiliation(s)
- Ji-Woong Shin
- Stem Cell Neuroplasticity Research Group, Kyungpook National University, Daegu, Korea
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41
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Banisadr G, Bhattacharyya BJ, Belmadani A, Izen SC, Ren D, Tran PB, Miller RJ. The chemokine BRAK/CXCL14 regulates synaptic transmission in the adult mouse dentate gyrus stem cell niche. J Neurochem 2011; 119:1173-82. [PMID: 21955359 DOI: 10.1111/j.1471-4159.2011.07509.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The chemokine BRAK/CXCL14 is an ancient member of the chemokine family whose functions in the brain are completely unknown. We examined the distribution of CXCL14 in the nervous system during development and in the adult. Generally speaking, CXCL14 was not expressed in the nervous system prior to birth, but it was expressed in the developing whisker follicles (E14.5) and subsequently in the hair follicles and skin. Postnatally, CXCL14 was also highly expressed in many regions of the brain, including the cortex, basal ganglia, septum and hippocampus. CXCL14 was also highly expressed in the dorsal root ganglia. We observed that in the hippocampal dentate gyrus (DG) CXCL14 was expressed by GABAergic interneurons. We demonstrated that CXCL14 inhibited GABAergic transmission to nestin-EGFP-expressing neural stem/progenitor cells in the adult DG. CXCL14 inhibited both the tonic and phasic effects of synaptically released GABA. In contrast CXCL12 enhanced the effects of GABA at these same synapses. CXCL14 increased [Ca(2+)](i) in neural stem cells cultured from the postnatal brain indicating that they expressed the CXCL14 receptor. These observations are consistent with the view that CXCL12 and CXCL14 may normally act as positive and negative regulators of the effects of GABA in the adult DG stem cell niche.
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Affiliation(s)
- Ghazal Banisadr
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University School of Medicine, Chicago, Illinois, USA
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42
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Masiulis I, Yun S, Eisch AJ. The interesting interplay between interneurons and adult hippocampal neurogenesis. Mol Neurobiol 2011; 44:287-302. [PMID: 21956642 DOI: 10.1007/s12035-011-8207-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 09/07/2011] [Indexed: 10/17/2022]
Abstract
Adult neurogenesis is a unique form of plasticity found in the hippocampus, a brain region key to learning and memory formation. While many external stimuli are known to modulate the generation of new neurons in the hippocampus, little is known about the local circuitry mechanisms that regulate the process of adult neurogenesis. The neurogenic niche in the hippocampus is highly complex and consists of a heterogeneous population of cells including interneurons. Because interneurons are already highly integrated into the hippocampal circuitry, they are in a prime position to influence the proliferation, survival, and maturation of adult-generated cells in the dentate gyrus. Here, we review the current state of our understanding on the interplay between interneurons and adult hippocampal neurogenesis. We focus on activity- and signaling-dependent mechanisms, as well as research on human diseases that could provide better insight into how interneurons in general might add to our comprehension of the regulation and function of adult hippocampal neurogenesis.
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Affiliation(s)
- Irene Masiulis
- UT Southwestern Medical Center, Dallas, TX 75390-9070, USA.
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43
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Wilson NM, Jung H, Ripsch MS, Miller RJ, White FA. CXCR4 signaling mediates morphine-induced tactile hyperalgesia. Brain Behav Immun 2011; 25:565-73. [PMID: 21193025 PMCID: PMC3039030 DOI: 10.1016/j.bbi.2010.12.014] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 12/17/2010] [Accepted: 12/18/2010] [Indexed: 01/15/2023] Open
Abstract
Morphine and related compounds are the first line of therapy in the treatment of moderate to severe pain. Over time, individuals taking opioids can develop an increasing sensitivity to noxious stimuli, even evolving into a painful response to previously non-noxious stimuli (opioid-induced hyperalgesia; OIH). The mechanism underlying OIH is not well understood although complex intracellular neural mechanisms, including opioid receptor desensitization and down-regulation, are believed to be major mechanisms underlying OIH. However, OIH may also be associated with changes in gene expression. A growing body of evidence suggests that cellular exposure to mu agonists upregulate chemokines/receptors and recent work from our laboratory implicates chemokine upregulation in a variety of neuropathic pain behaviors. Here we characterized the degree to which chemokines/receptors signaling is increased in primary afferent neurons of the dorsal root ganglion (DRG) following chronic morphine sulfate treatment and correlated these changes with tactile hyperalgesic behavior in rodents. We demonstrate that mRNA expression of the chemokine, stromal-derived factor-1 (SDF1/CXCL12) is upregulated following morphine treatment in sensory neurons of the rat. The release of SDF1 was found to be constitutive when compared with the activity dependent release of the C-C chemokine, monocyte chemoattractant protein-1 (MCP1/CCL2) in a line of F11 neuroblastoma-sensory neuron hybrid cells. We further determined that there is pronounced CXCR4 expression in satellite glial cells and following morphine treatment, increased functional CXCR4 expression in sensory neurons of the DRG. Moreover, intraperitoneal administration of the specific CXCR4 antagonist, AMD3100, completely reversed OIH in the rat. Taken together; the data suggest that opioid-induced SDF1/CXCR4 signaling is central to the development of long lasting OIH and that receptor antagonists represent a promising novel approach to the management of the side effects associated with the use of opioids for chronic pain management.
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Affiliation(s)
- Natalie M. Wilson
- Department of Pharmacology, Loyola University, Chicago, Maywood, Illinois 60153
| | - Hosung Jung
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, Chicago, IL 60611
| | - Matthew S. Ripsch
- Department of Anesthesia, Indiana University, Indianapolis, IN 46208
| | - Richard J. Miller
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, Chicago, IL 60611
| | - Fletcher A. White
- Department of Anesthesia, Program in Medical Neurosciences, Stark Neurosciences Research Institute, Indiana University, Indianapolis, IN 46208
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44
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Sánchez-Alcañiz JA, Haege S, Mueller W, Pla R, Mackay F, Schulz S, López-Bendito G, Stumm R, Marín O. Cxcr7 controls neuronal migration by regulating chemokine responsiveness. Neuron 2011; 69:77-90. [PMID: 21220100 DOI: 10.1016/j.neuron.2010.12.006] [Citation(s) in RCA: 232] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2010] [Indexed: 12/17/2022]
Abstract
The chemokine Cxcl12 binds Cxcr4 and Cxcr7 receptors to control cell migration in multiple biological contexts, including brain development, leukocyte trafficking, and tumorigenesis. Both receptors are expressed in the CNS, but how they cooperate during migration has not been elucidated. Here, we used the migration of cortical interneurons as a model to study this process. We found that Cxcr4 and Cxcr7 are coexpressed in migrating interneurons, and that Cxcr7 is essential for chemokine signaling. Intriguingly, this process does not exclusively involve Cxcr7, but most critically the modulation of Cxcr4 function. Thus, Cxcr7 is necessary to regulate Cxcr4 protein levels, thereby adapting chemokine responsiveness in migrating cells. This demonstrates that a chemokine receptor modulates the function of another chemokine receptor by controlling the amount of protein that is made available for signaling at the cell surface.
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45
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Hartman NW, Carpentino JE, LaMonica K, Mor DE, Naegele JR, Grabel L. CXCL12-mediated guidance of migrating embryonic stem cell-derived neural progenitors transplanted into the hippocampus. PLoS One 2010; 5:e15856. [PMID: 21209827 PMCID: PMC3013129 DOI: 10.1371/journal.pone.0015856] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 11/26/2010] [Indexed: 01/19/2023] Open
Abstract
Stem cell therapies for neurodegenerative disorders require accurate delivery of the transplanted cells to the sites of damage. Numerous studies have established that fluid injections to the hippocampus can induce lesions in the dentate gyrus (DG) that lead to cell death within the upper blade. Using a mouse model of temporal lobe epilepsy, we previously observed that embryonic stem cell-derived neural progenitors (ESNPs) survive and differentiate within the granule cell layer after stereotaxic delivery to the DG, replacing the endogenous cells of the upper blade. To investigate the mechanisms for ESNP migration and repair in the DG, we examined the role of the chemokine CXCL12 in mice subjected to kainic acid-induced seizures. We now show that ESNPs transplanted into the DG show extensive migration through the upper blade, along the septotemporal axis of the hippocampus. Seizures upregulate CXCL12 and infusion of the CXCR4 antagonist AMD3100 by osmotic minipump attenuated ESNP migration. We also demonstrate that seizures promote the differentiation of transplanted ESNPs toward neuronal rather than astrocyte fates. These findings suggest that ESNPs transplanted into the adult rodent hippocampus migrate in response to cytokine-mediated signals.
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Affiliation(s)
- Nathaniel W Hartman
- Department of Biology, Wesleyan University, Middletown, Connecticut, United States of America.
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46
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Kobayashi NR, Hawes SM, Crook JM, Pébay A. G-protein coupled receptors in stem cell self-renewal and differentiation. Stem Cell Rev Rep 2010; 6:351-66. [PMID: 20625855 DOI: 10.1007/s12015-010-9167-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Stem cells have great potential for understanding early development, treating human disease, tissue trauma and early phase drug discovery. The factors that control the regulation of stem cell survival, proliferation, migration and differentiation are still emerging. Some evidence now exists demonstrating the potent effects of various G-protein coupled receptor (GPCR) ligands on the biology of stem cells. This review aims to give an overview of the current knowledge of the regulation of embryonic and somatic stem cell maintenance and differentiation by GPCR ligands.
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Ingold B, Schulz S, Budczies J, Neumann U, Ebert MPA, Weichert W, Röcken C. The role of vascular CXCR4 expression in colorectal carcinoma. Histopathology 2010; 55:576-86. [PMID: 19912363 DOI: 10.1111/j.1365-2559.2009.03426.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
AIMS The chemokine receptor CXCR4 plays a prominent role in the biology of many different tumours, promoting angiogenesis and metastasis. The impact of CXCR4 expression on tumour biology has been described in various gastrointestinal malignancies, but data on its in situ expression and clinicopathological correlations are sparse. Using a novel specific rabbit anti-CXCR4 antibody, the aim was to assess CXCR4 expression immunohistochemically on tissue microarrays generated from 402 colorectal cancers (CRCs) and compare it with CXCL12 expression and various clinicopathological parameters. METHODS AND RESULTS CXCR4-expressing tumour cells were observed in 31% of the cases, and expression correlated only with blood vessel invasion (P = 0.049). Furthermore, CXCR4 was found in tumour microvessels in 25% of CRCs. This pattern of CXCR4 expression correlated significantly with T- (P = 0.008), N- (P = 0.009), M- (P = 0.043), L- (P = 0.014) and V-category (P = 0.043) as well as with International Union Against Cancer (UICC) stage (P = 0.001). Furthermore, in node negative CRCs, vascular CXCR4 expression was an independent adverse prognostic factor [hazard ratio 2.87 (1.31-6.29), P = 0.009]. No correlation with CXCL12 expression was found. CONCLUSIONS Our data provide evidence that CXCR4 plays an important role in tumour angiogenesis of CRC. Therefore, the CXCR4 pathway is a promising therapeutic target for anti-angiogenic therapies in CRC.
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Affiliation(s)
- Barbara Ingold
- Institute of Pathology Campus Mitte, Charité University Hospital, Berlin, Germany.
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Ransohoff RM. Chemokines and chemokine receptors: standing at the crossroads of immunobiology and neurobiology. Immunity 2009; 31:711-21. [PMID: 19836265 DOI: 10.1016/j.immuni.2009.09.010] [Citation(s) in RCA: 269] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Accepted: 09/29/2009] [Indexed: 12/11/2022]
Abstract
There are several molecular entities common to the immune and nervous systems. Salient among them are the chemokines and their receptors, which play remarkably varied and potent roles in immunobiology and neurobiology. This review limns several illustrative examples and presents general principles of chemokine action that are manifest in both systems. These include the following: (1) chemokines tend equally to arrest cells and to make them move, in the process of positioning target cells with spatiotemporal precision; (2) signaling and nonsignaling receptors collaborate to adjust the chemokine environment for maximal efficacy; and (3) expression of a single chemokine receptor on circulating blood cells and parenchymal cells is often used to coordinate complex tissue responses. The challenge is to integrate knowledge of the roles of key receptors (as well as their ligands) into a coherent account of events during pathologic processes, in order to guide therapeutic development.
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Affiliation(s)
- Richard M Ransohoff
- Neuroinflammation Research Center (Lerner Research Institute) and Mellen Center for MS Treatment and Research (Neurological Institute), Cleveland Clinic, Mail Code NC30, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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Bruel-Jungerman E, Veyrac A, Dufour F, Horwood J, Laroche S, Davis S. Inhibition of PI3K-Akt signaling blocks exercise-mediated enhancement of adult neurogenesis and synaptic plasticity in the dentate gyrus. PLoS One 2009; 4:e7901. [PMID: 19936256 PMCID: PMC2775944 DOI: 10.1371/journal.pone.0007901] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 10/23/2009] [Indexed: 02/06/2023] Open
Abstract
Background Physical exercise has been shown to increase adult neurogenesis in the dentate gyrus and enhances synaptic plasticity. The antiapoptotic kinase, Akt has also been shown to be phosphorylated following voluntary exercise; however, it remains unknown whether the PI3K-Akt signaling pathway is involved in exercise-induced neurogenesis and the associated facilitation of synaptic plasticity in the dentate gyrus. Methodology/Principal Findings To gain insight into the potential role of this signaling pathway in exercise-induced neurogenesis and LTP in the dentate gyrus rats were infused with the PI3K inhibitor, LY294002 or vehicle control solution (icv) via osmotic minipumps and exercised in a running wheel for 10 days. Newborn cells in the dentate gyrus were date-labelled with BrdU on the last 3 days of exercise. Then, they were either returned to the home cage for 2 weeks to assess exercise-induced LTP and neurogenesis in the dentate gyrus, or were killed on the last day of exercise to assess proliferation and activation of the PI3K-Akt cascade using western blotting. Conclusions/Significance Exercise increases cell proliferation and promotes survival of adult-born neurons in the dentate gyrus. Immediately after exercise, we found that Akt and three downstream targets, BAD, GSK3β and FOXO1 were activated. LY294002 blocked exercise-induced phosphorylation of Akt and downstream target proteins. This had no effect on exercise-induced cell proliferation, but it abolished most of the beneficial effect of exercise on the survival of newly generated dentate gyrus neurons and prevented exercise-induced increase in dentate gyrus LTP. These results suggest that activation of the PI3 kinase-Akt signaling pathway plays a significant role via an antiapoptotic function in promoting survival of newly formed granule cells generated during exercise and the associated increase in synaptic plasticity in the dentate gyrus.
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Affiliation(s)
- Elodie Bruel-Jungerman
- CNRS, UMR 8620, Orsay, France
- Université Paris-Sud, Laboratoire de Neurobiologie de l'Apprentissage, de la Mémoire et de la Communication, UMR 8620, Orsay, France
| | - Alexandra Veyrac
- CNRS, UMR 8620, Orsay, France
- Université Paris-Sud, Laboratoire de Neurobiologie de l'Apprentissage, de la Mémoire et de la Communication, UMR 8620, Orsay, France
| | - Franck Dufour
- CNRS, UMR 8620, Orsay, France
- Université Paris-Sud, Laboratoire de Neurobiologie de l'Apprentissage, de la Mémoire et de la Communication, UMR 8620, Orsay, France
| | | | - Serge Laroche
- CNRS, UMR 8620, Orsay, France
- Université Paris-Sud, Laboratoire de Neurobiologie de l'Apprentissage, de la Mémoire et de la Communication, UMR 8620, Orsay, France
| | - Sabrina Davis
- CNRS, UMR 8620, Orsay, France
- Université Paris-Sud, Laboratoire de Neurobiologie de l'Apprentissage, de la Mémoire et de la Communication, UMR 8620, Orsay, France
- * E-mail:
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