1
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Zhao S, Mo G, Wang Q, Xu J, Yu S, Huang Z, Liu W, Zhang W. Role of RB1 in neurodegenerative diseases: inhibition of post-mitotic neuronal apoptosis via Kmt5b. Cell Death Discov 2024; 10:182. [PMID: 38637503 PMCID: PMC11026443 DOI: 10.1038/s41420-024-01955-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 12/04/2023] [Accepted: 04/10/2024] [Indexed: 04/20/2024] Open
Abstract
During the development of the vertebrate nervous system, 50% of the nerve cells undergo apoptosis shortly after formation. This process is important for sculpting tissue during morphogenesis and removing transiently functional cells that are no longer needed, ensuring the appropriate number of neurons in each region. Dysregulation of neuronal apoptosis can lead to neurodegenerative diseases. However, the molecular events involved in activating and regulating the neuronal apoptosis program are not fully understood. In this study, we identified several RB1 mutations in patients with neurodegenerative diseases. Then, we used a zebrafish model to investigate the role of Rb1 in neuronal apoptosis. We showed that Rb1-deficient mutants exhibit a significant hindbrain neuronal apoptosis, resulting in increased microglia infiltration. We further revealed that the apoptotic neurons in Rb1-deficient zebrafish were post-mitotic neurons, and Rb1 inhibits the apoptosis of these neurons by regulating bcl2/caspase through binding to Kmt5b. Moreover, using this zebrafish mutant, we verified the pathogenicity of the R621S and L819V mutations of human RB1 in neuronal apoptosis. Collectively, our data indicate that the Rb1-Kmt5b-caspase/bcl2 axis is crucial for protecting post-mitotic neurons from apoptosis and provides an explanation for the pathogenesis of clinically relevant mutations.
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Affiliation(s)
- Shuang Zhao
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, 510006, China
| | - Guiling Mo
- Guangzhou KingMed Diagnostics Group Co., Ltd., International Biotech Island, Guangzhou, 510005, China
| | - Qiang Wang
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, 510006, China
| | - Jin Xu
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, 510006, China
| | - Shihui Yu
- Guangzhou KingMed Diagnostics Group Co., Ltd., International Biotech Island, Guangzhou, 510005, China
| | - Zhibin Huang
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, 510006, China
| | - Wei Liu
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, 510006, China.
| | - Wenqing Zhang
- The Innovation Centre of Ministry of Education for Development and Diseases, School of Medicine, South China University of Technology, Guangzhou, 510006, China.
- Greater Bay Biomedical Innocenter, Shenzhen Bay Laboratory, Shenzhen, 518055, China.
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2
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Simchi L, Gupta PK, Feuermann Y, Kaphzan H. Elevated ROS levels during the early development of Angelman syndrome alter the apoptotic capacity of the developing neural precursor cells. Mol Psychiatry 2023; 28:2382-2397. [PMID: 36991133 PMCID: PMC10611580 DOI: 10.1038/s41380-023-02038-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/01/2023] [Accepted: 03/14/2023] [Indexed: 03/31/2023]
Abstract
Angelman syndrome (AS) is a rare genetic neurodevelopmental disorder caused by the maternally inherited loss of function of the UBE3A gene. AS is characterized by a developmental delay, lack of speech, motor dysfunction, epilepsy, autistic features, happy demeanor, and intellectual disability. While the cellular roles of UBE3A are not fully understood, studies suggest that the lack of UBE3A function is associated with elevated levels of reactive oxygen species (ROS). Despite the accumulating evidence emphasizing the importance of ROS during early brain development and its involvement in different neurodevelopmental disorders, up to date, the levels of ROS in AS neural precursor cells (NPCs) and the consequences on AS embryonic neural development have not been elucidated. In this study we show multifaceted mitochondrial aberration in AS brain-derived embryonic NPCs, which exhibit elevated mitochondrial membrane potential (ΔΨm), lower levels of endogenous reduced glutathione, excessive mitochondrial ROS (mROS) levels, and increased apoptosis compared to wild-type (WT) littermates. In addition, we report that glutathione replenishment by glutathione-reduced ethyl ester (GSH-EE) corrects the excessive mROS levels and attenuates the enhanced apoptosis in AS NPCs. Studying the glutathione redox imbalance and mitochondrial abnormalities in embryonic AS NPCs provides an essential insight into the involvement of UBE3A in early neural development, information that can serve as a powerful avenue towards a broader view of AS pathogenesis. Moreover, since mitochondrial dysfunction and elevated ROS levels were associated with other neurodevelopmental disorders, the findings herein suggest some potential shared underlying mechanisms for these disorders as well.
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Affiliation(s)
- Lilach Simchi
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Pooja Kri Gupta
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Yonatan Feuermann
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Hanoch Kaphzan
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
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3
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Wiegreffe C, Wahl T, Joos NS, Bonnefont J, Liu P, Britsch S. Developmental cell death of cortical projection neurons is controlled by a Bcl11a/Bcl6‐dependent pathway. EMBO Rep 2022; 23:e54104. [PMID: 35766181 PMCID: PMC9346488 DOI: 10.15252/embr.202154104] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 05/31/2022] [Accepted: 06/08/2022] [Indexed: 12/05/2022] Open
Abstract
Developmental neuron death plays a pivotal role in refining organization and wiring during neocortex formation. Aberrant regulation of this process results in neurodevelopmental disorders including impaired learning and memory. Underlying molecular pathways are incompletely determined. Loss of Bcl11a in cortical projection neurons induces pronounced cell death in upper‐layer cortical projection neurons during postnatal corticogenesis. We use this genetic model to explore genetic mechanisms by which developmental neuron death is controlled. Unexpectedly, we find Bcl6, previously shown to be involved in the transition of cortical neurons from progenitor to postmitotic differentiation state to provide a major checkpoint regulating neuron survival during late cortical development. We show that Bcl11a is a direct transcriptional regulator of Bcl6. Deletion of Bcl6 exerts death of cortical projection neurons. In turn, reintroduction of Bcl6 into Bcl11a mutants prevents induction of cell death in these neurons. Together, our data identify a novel Bcl11a/Bcl6‐dependent molecular pathway in regulation of developmental cell death during corticogenesis.
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Affiliation(s)
| | - Tobias Wahl
- Institute of Molecular and Cellular Anatomy Ulm University Ulm Germany
| | | | - Jerome Bonnefont
- Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), and ULB Neuroscience Institute (UNI) Université Libre de Bruxelles (ULB) Brussels Belgium
- VIB‐KU Leuven Center for Brain & Disease Research, KU Leuven Department of Neuroscience Leuven Brain Institute Leuven Belgium
| | - Pentao Liu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine The University of Hong Kong Hong Kong China
| | - Stefan Britsch
- Institute of Molecular and Cellular Anatomy Ulm University Ulm Germany
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4
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Exploring the Origin and Physiological Significance of DNA Double Strand Breaks in the Developing Neuroretina. Int J Mol Sci 2022; 23:ijms23126449. [PMID: 35742893 PMCID: PMC9224223 DOI: 10.3390/ijms23126449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/06/2022] [Accepted: 06/07/2022] [Indexed: 02/04/2023] Open
Abstract
Genetic mosaicism is an intriguing physiological feature of the mammalian brain that generates altered genetic information and provides cellular, and prospectively functional, diversity in a manner similar to that of the immune system. However, both its origin and its physiological significance remain poorly characterized. Most, if not all, cases of somatic mosaicism require prior generation and repair of DNA double strand breaks (DSBs). The relationship between DSB generation, neurogenesis, and early neuronal cell death revealed by our studies in the developing retina provides new perspectives on the different mechanisms that contribute to DNA rearrangements in the developing brain. Here, we speculate on the physiological significance of these findings.
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5
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Liu KE, Raymond MH, Ravichandran KS, Kucenas S. Clearing Your Mind: Mechanisms of Debris Clearance After Cell Death During Neural Development. Annu Rev Neurosci 2022; 45:177-198. [PMID: 35226828 PMCID: PMC10157384 DOI: 10.1146/annurev-neuro-110920-022431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurodevelopment and efferocytosis have fascinated scientists for decades. How an organism builds a nervous system that is precisely tuned for efficient behaviors and survival and how it simultaneously manages constant somatic cell turnover are complex questions that have resulted in distinct fields of study. Although neurodevelopment requires the overproduction of cells that are subsequently pruned back, very few studies marry these fields to elucidate the cellular and molecular mechanisms that drive nervous system development through the lens of cell clearance. In this review, we discuss these fields to highlight exciting areas of future synergy. We first review neurodevelopment from the perspective of overproduction and subsequent refinement and then discuss who clears this developmental debris and the mechanisms that control these events. We then end with how a more deliberate merger of neurodevelopment and efferocytosis could reframe our understanding of homeostasis and disease and discuss areas of future study. Expected final online publication date for the Annual Review of Neuroscience, Volume 45 is July 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Kendra E Liu
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia, USA
| | - Michael H Raymond
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Center for Clearance, University of Virginia, Charlottesville, Virginia, USA
| | - Kodi S Ravichandran
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Center for Clearance, University of Virginia, Charlottesville, Virginia, USA.,Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA.,VIB-UGent Center for Inflammation Research and the Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Sarah Kucenas
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia, USA; .,Program in Fundamental Neuroscience, University of Virginia, Charlottesville, Virginia, USA.,Department of Biology, University of Virginia, Charlottesville, Virginia, USA
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6
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Levi H, Bar E, Cohen-Adiv S, Sweitat S, Kanner S, Galron R, Mitiagin Y, Barzilai A. Dysfunction of cerebellar microglia in Ataxia-telangiectasia. Glia 2021; 70:536-557. [PMID: 34854502 DOI: 10.1002/glia.24122] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 12/13/2022]
Abstract
Ataxia-telangiectasia (A-T) is a multisystem autosomal recessive disease caused by mutations in the ATM gene and characterized by cerebellar atrophy, progressive ataxia, immunodeficiency, male and female sterility, radiosensitivity, cancer predisposition, growth retardation, insulin-resistant diabetes, and premature aging. ATM phosphorylates more than 1500 target proteins, which are involved in cell cycle control, DNA repair, apoptosis, modulation of chromatin structure, and other cytoplasmic as well as mitochondrial processes. In our quest to better understand the mechanisms by which ATM deficiency causes cerebellar degeneration, we hypothesized that specific vulnerabilities of cerebellar microglia underlie the etiology of A-T. Our hypothesis is based on the recent finding that dysfunction of glial cells affect a variety of process leading to impaired neuronal functionality (Song et al., 2019). Whereas astrocytes and neurons descend from the neural tube, microglia originate from the hematopoietic system, invade the brain at early embryonic stage, and become the innate immune cells of the central nervous system and important participants in development of synaptic plasticity. Here we demonstrate that microglia derived from Atm-/- mouse cerebellum display accelerated cell migration and are severely impaired in phagocytosis, secretion of neurotrophic factors, and mitochondrial activity, suggestive of apoptotic processes. Interestingly, no microglial impairment was detected in Atm-deficient cerebral cortex, and Atm deficiency had less impact on astroglia than microglia. Collectively, our findings validate the roles of glial cells in cerebellar attrition in A-T.
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Affiliation(s)
- Hadar Levi
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ela Bar
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Stav Cohen-Adiv
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Suzan Sweitat
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Sivan Kanner
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ronit Galron
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Yulia Mitiagin
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ari Barzilai
- Department of Neurobiology, George S. Wise, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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7
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Azoxystrobin Impairs Neuronal Migration and Induces ROS Dependent Apoptosis in Cortical Neurons. Int J Mol Sci 2021; 22:ijms222212495. [PMID: 34830376 PMCID: PMC8622671 DOI: 10.3390/ijms222212495] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/17/2021] [Accepted: 11/17/2021] [Indexed: 11/17/2022] Open
Abstract
Fungicides often cause genotoxic stress and neurodevelopmental disorders such as autism (ASD). Fungicide-azoxystrobin (AZOX) showed acute and chronic toxicity to various organisms, and remained a concern for ill effects in developing neurons. We evaluated the neurotoxicity of AZOX in developing mouse brains, and observed prenatal exposure to AZOX reduced neuronal viability, neurite outgrowth, and cortical migration process in developing brains. The 50% inhibitory concentration (IC50) of AZOX for acute (24 h) and chronic (7 days) exposures were 30 and 10 μM, respectively. Loss in viability was due to the accumulation of reactive oxygen species (ROS), and inhibited neurite outgrowth was due to the deactivation of mTORC1 kinase activity. Pretreatment with ROS scavenger- N-acetylcysteine (NAC) reserved the viability loss and forced activation of mTORC1 kinase revived the neurite outgrowth in AZOX treated neurons. Intra-amniotic injection of AZOX coupled with in utero electroporation of GFP-labelled plasmid in E15.5 mouse was performed and 20 mg/kg AZOX inhibited radial neuronal migration. Moreover, the accumulation of mitochondria was significantly reduced in AZOX treated primary neurons, indicative of mitochondrial deactivation and induction of apoptosis, which was quantified by Bcl2/Bax ratio and caspase 3 cleavage assay. This study elucidated the neurotoxicity of AZOX and explained the possible cure from it.
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8
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Transitory and Vestigial Structures of the Developing Human Nervous System. Pediatr Neurol 2021; 123:86-101. [PMID: 34416613 DOI: 10.1016/j.pediatrneurol.2021.07.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 07/02/2021] [Accepted: 07/03/2021] [Indexed: 11/23/2022]
Abstract
As with many body organs, the human central nervous system contains many structures and cavities that may have had functions in embryonic and fetal life but are vestigial or atrophic at maturity. Examples are the septum pellucidum, remnants of the lamina terminalis, Cajal-Retzius neurons, induseum griseum, habenula, and accessory olfactory bulb. Other structures are transitory in fetal or early postnatal life, disappearing from the mature brain. Examples are the neural crest, subpial granular glial layer of Brun over cerebral cortex, radial glial cells, and subplate zone of cerebral cortex. At times persistent fetal structures that do not regress may cause neurological problems or indicate a pathologic condition, such as Blake pouch cyst. Transitory structures thus can become vestigial. Examples are an excessively wide cavum septi pellucidi, suprapineal recess of the third ventricle, trigeminal artery of the posterior fossa circulation, and hyaloid ocular artery. Arrested maturation might be considered another aspect of vestigial structure. An example is the persistent microcolumnar cortical architecture in focal cortical dysplasia type Ia, in cortical zones of chronic fetal ischemia, and in some metabolic/genetic congenital encephalopathies. Some transitory structures in human brain are normal adult structures in lower vertebrates. Recognition of transitory and vestigial structures by fetal or postnatal neuroimaging and neuropathologically enables better understanding of cerebral ontogenesis and avoids misinterpretations.
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9
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Abstract
Long-term effective use of antiretroviral therapy (ART) among people with HIV (PWH) has significantly reduced the burden of disease, yet a cure for HIV has not been universally achieved, likely due to the persistence of an HIV reservoir. The central nervous system (CNS) is an understudied HIV sanctuary. Importantly, due to viral persistence in the brain, cognitive disturbances persist to various degrees at high rates in PWH despite suppressive ART. Given the complexity and accessibility of the CNS compartment and that it is a physiologically and anatomically unique immune site, human studies to reveal molecular mechanisms of viral entry, reservoir establishment, and the cellular and structural interactions leading to viral persistence and brain injury to advance a cure and either prevent or limit cognitive impairments in PWH remain challenging. Recent advances in human brain organoids show that they can mimic the intercellular dynamics of the human brain and may recapitulate many of the events involved in HIV infection of the brain (neuroHIV). Human brain organoids can be produced, spontaneously or with addition of growth factors and at immature or mature states, and have become stronger models to study neurovirulent viral infections of the CNS. While organoids provide opportunities to study neuroHIV, obstacles such as the need to incorporate microglia need to be overcome to fully utilize this model. Here, we review the current achievements in brain organoid biology and their relevance to neuroHIV research efforts.
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10
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Asadzadeh Z, Safarzadeh E, Safaei S, Baradaran A, Mohammadi A, Hajiasgharzadeh K, Derakhshani A, Argentiero A, Silvestris N, Baradaran B. Current Approaches for Combination Therapy of Cancer: The Role of Immunogenic Cell Death. Cancers (Basel) 2020; 12:E1047. [PMID: 32340275 PMCID: PMC7226590 DOI: 10.3390/cancers12041047] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/08/2020] [Accepted: 04/17/2020] [Indexed: 12/31/2022] Open
Abstract
Cell death resistance is a key feature of tumor cells. One of the main anticancer therapies is increasing the susceptibility of cells to death. Cancer cells have developed a capability of tumor immune escape. Hence, restoring the immunogenicity of cancer cells can be suggested as an effective approach against cancer. Accumulating evidence proposes that several anticancer agents provoke the release of danger-associated molecular patterns (DAMPs) that are determinants of immunogenicity and stimulate immunogenic cell death (ICD). It has been suggested that ICD inducers are two different types according to their various activities. Here, we review the well-characterized DAMPs and focus on the different types of ICD inducers and recent combination therapies that can augment the immunogenicity of cancer cells.
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Affiliation(s)
- Zahra Asadzadeh
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz 5165665811, Iran; (Z.A.); (S.S.); (K.H.); (A.D.)
| | - Elham Safarzadeh
- Department of Immunology and Microbiology, Faculty of Medicine, Ardabil University of Medical Sciences, Ardabil 5618985991, Iran;
| | - Sahar Safaei
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz 5165665811, Iran; (Z.A.); (S.S.); (K.H.); (A.D.)
| | - Ali Baradaran
- Research & Development Lab, BSD Robotics, 4500 Brisbane, Australia;
| | - Ali Mohammadi
- Department of Cancer and Inflammation Research, Institute for Molecular Medicine, University of Southern Denmark, 5230 Odense, Denmark;
| | - Khalil Hajiasgharzadeh
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz 5165665811, Iran; (Z.A.); (S.S.); (K.H.); (A.D.)
| | - Afshin Derakhshani
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz 5165665811, Iran; (Z.A.); (S.S.); (K.H.); (A.D.)
| | | | - Nicola Silvestris
- IRCCS Istituto Tumori “Giovanni Paolo II” of Bari, 70124 Bari, Italy;
- Department of Biomedical Sciences and Human Oncology, University of Bari “Aldo Moro”, 70124 Bari, Italy
| | - Behzad Baradaran
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz 5165665811, Iran; (Z.A.); (S.S.); (K.H.); (A.D.)
- Department of Immunology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz 5166614766, Iran
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11
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Sena E, Bou-Rouphael J, Rocques N, Carron-Homo C, Durand BC. Mcl1 protein levels and Caspase-7 executioner protease control axial organizer cells survival. Dev Dyn 2020; 249:847-866. [PMID: 32141178 DOI: 10.1002/dvdy.169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 02/05/2020] [Accepted: 02/29/2020] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Organizing centers are groups of specialized cells that secrete morphogens, thereby influencing development of their neighboring territories. Apoptosis is a form of programmed cell death reported to limit the size of organizers. Little is known about the identity of intracellular signals driving organizer cell death. Here we investigated in Xenopus the role of both the anti-apoptotic protein Myeloid-cell-leukemia 1 (Mcl1) and the cysteine proteases Caspase-3 and Caspase-7 in formation of the axial organizing center-the notochord-that derives from the Spemann organizer, and participates in the induction and patterning of the neuroepithelium. RESULTS We confirm a role for apoptosis in establishing the axial organizer in early neurula. We show that the expression pattern of mcl1 is coherent with a role for this gene in early notochord development. Using loss of function approaches, we demonstrate that Mcl1 depletion decreases neuroepithelium width and increases notochord cells apoptosis, a process that relies on Caspase-7, and not on Caspase-3, activity. Our data provide evidence that Mcl1 protein levels physiologically control notochord cells' survival and that Caspase-7 is the executioner protease in this developmental process. CONCLUSIONS Our study reveals new functions for Mcl1 and Caspase-7 in formation of the axial signalling center.
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Affiliation(s)
- Elena Sena
- Institut Curie, PSL Research University, Orsay, France.,Université Paris Sud, Orsay, France
| | - Johnny Bou-Rouphael
- Sorbonne Université, CNRS UMR7622, IBPS Developmental Biology Laboratory, Paris, France
| | - Nathalie Rocques
- Institut Curie, PSL Research University, Orsay, France.,Université Paris Sud, Orsay, France
| | - Clémence Carron-Homo
- Sorbonne Université, CNRS UMR7622, IBPS Developmental Biology Laboratory, Paris, France
| | - Béatrice C Durand
- Institut Curie, PSL Research University, Orsay, France.,Université Paris Sud, Orsay, France.,Sorbonne Université, CNRS UMR7622, IBPS Developmental Biology Laboratory, Paris, France
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12
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Mavrovic M, Uvarov P, Delpire E, Vutskits L, Kaila K, Puskarjov M. Loss of non-canonical KCC2 functions promotes developmental apoptosis of cortical projection neurons. EMBO Rep 2020; 21:e48880. [PMID: 32064760 DOI: 10.15252/embr.201948880] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 01/16/2020] [Accepted: 01/24/2020] [Indexed: 01/01/2023] Open
Abstract
KCC2, encoded in humans by the SLC12A5 gene, is a multifunctional neuron-specific protein initially identified as the chloride (Cl- ) extruder critical for hyperpolarizing GABAA receptor currents. Independently of its canonical function as a K-Cl cotransporter, KCC2 regulates the actin cytoskeleton via molecular interactions mediated through its large intracellular C-terminal domain (CTD). Contrary to the common assumption that embryonic neocortical projection neurons express KCC2 at non-significant levels, here we show that loss of KCC2 enhances apoptosis of late-born upper-layer cortical projection neurons in the embryonic brain. In utero electroporation of plasmids encoding truncated, transport-dead KCC2 constructs retaining the CTD was as efficient as of that encoding full-length KCC2 in preventing elimination of migrating projection neurons upon conditional deletion of KCC2. This was in contrast to the effect of a full-length KCC2 construct bearing a CTD missense mutation (KCC2R952H ), which disrupts cytoskeletal interactions and has been found in patients with neurological and psychiatric disorders, notably seizures and epilepsy. Together, our findings indicate ion transport-independent, CTD-mediated regulation of developmental apoptosis by KCC2 in migrating cortical projection neurons.
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Affiliation(s)
- Martina Mavrovic
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Pavel Uvarov
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University, Nashville, TN, USA
| | - Laszlo Vutskits
- Department of Basic Neurosciences, University of Geneva Medical School, Geneva 4, Switzerland.,Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva, Geneva 4, Switzerland
| | - Kai Kaila
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Martin Puskarjov
- Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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13
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Álvarez-Lindo N, Baleriola J, de Los Ríos V, Suárez T, de la Rosa EJ. RAG-2 deficiency results in fewer phosphorylated histone H2AX foci, but increased retinal ganglion cell death and altered axonal growth. Sci Rep 2019; 9:18486. [PMID: 31811168 PMCID: PMC6898044 DOI: 10.1038/s41598-019-54873-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 11/19/2019] [Indexed: 02/06/2023] Open
Abstract
DNA double-strand breaks (DSBs), selectively visualized as γ-H2AX+ foci, occur during the development of the central nervous system, including the retina, although their origin and biological significance are poorly understood. Mutant mice with DSB repair mechanism defects exhibit increased numbers of γ-H2AX+ foci, increased cell death during neural development, and alterations in axonogenesis in the embryonic retina. The aim of this study was to identify putative sources of DSBs. One of the identified DSBs sources is LINE-1 retrotransposition. While we did not detect changes in LINE-1 DNA content during the early period of cell death associated with retinal neurogenesis, retinal development was altered in mice lacking RAG-2, a component of the RAG-1,2-complex responsible for initiating somatic recombination in lymphocytes. Although γ-H2AX+ foci were less abundant in the rag2−/− mouse retina, retinal ganglion cell death was increased and axonal growth and navigation were impaired in the RAG-2 deficient mice, a phenotype shared with mutant mice with defective DNA repair mechanisms. These findings demonstrate that RAG-2 is necessary for proper retinal development, and suggest that both DSB generation and repair are genuine processes intrinsic to neural development.
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Affiliation(s)
- Noemí Álvarez-Lindo
- 3D Lab: Development, Differentiation & Degeneration, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CIB/CSIC), Madrid, Spain
| | - Jimena Baleriola
- 3D Lab: Development, Differentiation & Degeneration, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CIB/CSIC), Madrid, Spain.,Laboratory of local translation in neurons and glia, Achucarro Basque Center for Neuroscience; Department of Cell Biology and Histology, University of the Basque Country, Leioa; and Ikerbasque Foundation, Bilbao, Bizkaia, Spain
| | - Vivian de Los Ríos
- Proteomics and Genomics, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CIB/CSIC), Madrid, Spain
| | - Teresa Suárez
- 3D Lab: Development, Differentiation & Degeneration, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CIB/CSIC), Madrid, Spain
| | - Enrique J de la Rosa
- 3D Lab: Development, Differentiation & Degeneration, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas (CIB/CSIC), Madrid, Spain.
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14
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Matamoro-Vidal A, Levayer R. Multiple Influences of Mechanical Forces on Cell Competition. Curr Biol 2019; 29:R762-R774. [DOI: 10.1016/j.cub.2019.06.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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15
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Miltner AM, Mercado-Ayon Y, Cheema SK, Zhang P, Zawadzki RJ, La Torre A. A Novel Reporter Mouse Uncovers Endogenous Brn3b Expression. Int J Mol Sci 2019; 20:E2903. [PMID: 31197108 PMCID: PMC6627301 DOI: 10.3390/ijms20122903] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 12/18/2022] Open
Abstract
Brn3b (Pou4f2) is a class-4 POU domain transcription factor known to play central roles in the development of different neuronal populations of the Central Nervous System, including retinal ganglion cells (RGCs), the neurons that connect the retina with the visual centers of the brain. Here, we have used CRISPR-based genetic engineering to generate a Brn3b-mCherry reporter mouse without altering the endogenous expression of Brn3b. In our mouse line, mCherry faithfully recapitulates normal Brn3b expression in the retina, the optic tracts, the midbrain tectum, and the trigeminal ganglia. The high sensitivity of mCherry also revealed novel expression of Brn3b in the neuroectodermal cells of the optic stalk during early stages of eye development. Importantly, the fluorescent intensity of Brn3b-mCherry in our reporter mice allows for noninvasive live imaging of RGCs using Scanning Laser Ophthalmoscopy (SLO), providing a novel tool for longitudinal monitoring of RGCs.
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Affiliation(s)
- Adam M Miltner
- Department of Cell Biology and Human Anatomy, University of California-Davis, Davis, CA 95616, USA.
| | - Yesica Mercado-Ayon
- Department of Cell Biology and Human Anatomy, University of California-Davis, Davis, CA 95616, USA.
| | - Simranjeet K Cheema
- Department of Cell Biology and Human Anatomy, University of California-Davis, Davis, CA 95616, USA.
| | - Pengfei Zhang
- Department of Cell Biology and Human Anatomy, University of California-Davis, Davis, CA 95616, USA.
- UC Davis EyePod Small Animal Ocular Imaging Laboratory, University of California-Davis, Davis, CA 95616, USA.
| | - Robert J Zawadzki
- UC Davis EyePod Small Animal Ocular Imaging Laboratory, University of California-Davis, Davis, CA 95616, USA.
- Department of Ophthalmology and Vision Science, University of California-Davis, Sacramento, CA 95817, USA.
| | - Anna La Torre
- Department of Cell Biology and Human Anatomy, University of California-Davis, Davis, CA 95616, USA.
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16
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Abstract
Brain development is a highly regulated process that involves the precise spatio-temporal activation of cell signaling cues. Transcription factors play an integral role in this process by relaying information from external signaling cues to the genome. The transcription factor Forkhead box G1 (FOXG1) is expressed in the developing nervous system with a critical role in forebrain development. Altered dosage of FOXG1 due to deletions, duplications, or functional gain- or loss-of-function mutations, leads to a complex array of cellular effects with important consequences for human disease including neurodevelopmental disorders. Here, we review studies in multiple species and cell models where FOXG1 dose is altered. We argue against a linear, symmetrical relationship between FOXG1 dosage states, although FOXG1 levels at the right time and place need to be carefully regulated. Neurodevelopmental disease states caused by mutations in FOXG1 may therefore be regulated through different mechanisms.
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Affiliation(s)
- Nuwan C Hettige
- Department of Human Genetics, McGill University, Montreal, QC, Canada.,Psychiatric Genetics Group, Douglas Mental Health University Institute, Montreal, QC, Canada
| | - Carl Ernst
- Department of Human Genetics, McGill University, Montreal, QC, Canada.,Psychiatric Genetics Group, Douglas Mental Health University Institute, Montreal, QC, Canada.,Department of Psychiatry, McGill University, Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
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17
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Chen J, Gong X, Huang L, Chen P, Wang T, Zhou W, Luo K, Wang J. MiR-199a-5p regulates sirtuin1 and PI3K in the rat hippocampus with intrauterine growth restriction. Sci Rep 2018; 8:13813. [PMID: 30217997 PMCID: PMC6138635 DOI: 10.1038/s41598-018-32189-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 07/10/2018] [Indexed: 12/16/2022] Open
Abstract
In humans, malnutrition during pregnancy results in intrauterine growth restriction (IUGR) and an increased risk of neurological morbidities; altered miRNA characteristics have been suggested to contribute to IUGR neurological pathogenesis. A miRNA microarray was used to identify differentially expressed miRNA molecules in the hippocampi of rats with IUGR. Five of the molecules in question were selectively validated using real-time PCR in rats with IUGR. We then investigated the role of miR-199a-5p in hippocampal pathology. Bioinformatics analysis results suggested that TNF-α, caspase-3 and SIRT1 were potential targets of miR-199a-5p. Changes in PI3K, SIRT1 and caspase-3 protein expressions levels in the hippocampus were confirmed by Western blot analysis (all P < 0.05). Studies using the pheochromocytoma cell line PC12 cells and primary neurons demonstrated that miR-199a-5p modulated PI3K, caspase-3 and SIRT1 expression. Additionally, there was an inverse correlation between miR-199a-5p and caspase-3 expression, though dual-luciferase reporter assays showed that caspase-3 is not a target of miR-199a-5p. We conclude that IUGR affects hippocampal miRNAs characteristics. Our results also indicated that aberrantly high expression levels of miR-199a-5p may play an important role in the pathogenesis of IUGR by regulating SIRT1 and PI3K.
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Affiliation(s)
- Juncao Chen
- Institute of Pediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, 510623, China
- Division of Neonatology, The Second Xiangya Hospital, Central South University, 139 Renmin Middle Rd, Changsha, Hunan, 410011, China
| | - Xiaoyun Gong
- Division of Neonatology, The Second Xiangya Hospital, Central South University, 139 Renmin Middle Rd, Changsha, Hunan, 410011, China
| | - Li Huang
- Division of Neonatology, The Second Xiangya Hospital, Central South University, 139 Renmin Middle Rd, Changsha, Hunan, 410011, China
| | - Pingyang Chen
- Division of Neonatology, The Second Xiangya Hospital, Central South University, 139 Renmin Middle Rd, Changsha, Hunan, 410011, China.
| | - Tao Wang
- Division of Neonatology, The Second Xiangya Hospital, Central South University, 139 Renmin Middle Rd, Changsha, Hunan, 410011, China
| | - Wei Zhou
- Division of Neonatology, Guangzhou Women and Children's Medical Centre, Guangzhou Medical University, Guangzhou, 510623, China
| | - Kaiju Luo
- Division of Neonatology, The Second Xiangya Hospital, Central South University, 139 Renmin Middle Rd, Changsha, Hunan, 410011, China
| | - Jing Wang
- Division of Neonatology, The Second Xiangya Hospital, Central South University, 139 Renmin Middle Rd, Changsha, Hunan, 410011, China
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18
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Chen X, Wu H, Chen H, Wang Q, Xie XJ, Shen J. Astragaloside VI Promotes Neural Stem Cell Proliferation and Enhances Neurological Function Recovery in Transient Cerebral Ischemic Injury via Activating EGFR/MAPK Signaling Cascades. Mol Neurobiol 2018; 56:3053-3067. [PMID: 30088176 DOI: 10.1007/s12035-018-1294-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 08/01/2018] [Indexed: 12/13/2022]
Abstract
Radix Astragali (AR) is a commonly used medicinal herb for post-stroke disability in Traditional Chinese Medicine but its active compounds for promoting neurogenic effects are largely unknown. In the present study, we tested the hypothesis that Astragaloside VI could be a promising active compound from AR for adult neurogenesis and brain repair via targeting epidermal growth factor (EGF)-mediated MAPK signaling pathway in post-stroke treatment. By using cultured neural stem cells (NSCs) and experimental stroke rat model, we investigated the effects of Astragaloside VI on inducing NSCs proliferation and self-renewal in vitro, and enhancing neurogenesis for the recovery of the neurological functions in post-ischemic brains in vivo. For animal experiments, rats were undergone 1.5 h middle cerebral artery occlusion (MCAO) plus 7 days reperfusion. Astragaloside VI (2 μg/kg) was daily administrated by intravenous injection (i.v.) for 7 days. Astragaloside VI treatment promoted neurogenesis and astrogenic formation in dentate gyrus zone, subventricular zone, and cortex of the transient ischemic rat brains in vivo. Astragaloside VI treatment enhanced NSCs self-renewal and proliferation in the cultured NSCs in vitro without affecting NSCs differentiation. Western blot analysis showed that Astragaloside VI up-regulated the expression of nestin, p-EGFR and p-MAPK, and increased neurosphere sizes, whose effects were abolished by the co-treatment of EGF receptor inhibitor gefitinib and ERK inhibitor PD98059. Behavior tests revealed that Astragaloside VI promoted the spatial learning and memory and improved the impaired motor function in transient cerebral ischemic rats. Taken together, Astragaloside VI could effectively activate EGFR/MAPK signaling cascades, promote NSCs proliferation and neurogenesis in transient cerebral ischemic brains, and improve the repair of neurological functions in post-ischemic stroke rats. Astragaloside VI could be a new therapeutic drug candidate for post-stroke treatment.
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Affiliation(s)
- Xi Chen
- Department of Core Facility, The People's Hospital of Bao-an, Shenzhen, China.,The 8th people's Hospital of Shenzhen, The Affiliated Bao-an Hospital of Southern Medical University, Shenzhen, 518000, China.,School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 10 Sassoon Road, Pokfulam, Hong Kong, SAR, China
| | - Hao Wu
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 10 Sassoon Road, Pokfulam, Hong Kong, SAR, China
| | - Hansen Chen
- School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 10 Sassoon Road, Pokfulam, Hong Kong, SAR, China
| | - Qi Wang
- Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China
| | - Xue-Jiao Xie
- School of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha, China
| | - Jiangang Shen
- Department of Core Facility, The People's Hospital of Bao-an, Shenzhen, China. .,School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 10 Sassoon Road, Pokfulam, Hong Kong, SAR, China. .,Institute of Clinical Pharmacology, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China.
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19
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Nicolás-Ávila JA, Hidalgo A, Ballesteros I. Specialized functions of resident macrophages in brain and heart. J Leukoc Biol 2018; 104:743-756. [PMID: 29947422 DOI: 10.1002/jlb.6mr0118-041r] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 05/08/2018] [Accepted: 05/30/2018] [Indexed: 12/16/2022] Open
Abstract
The functions of macrophages in healthy tissues extend beyond their well-established roles as immune sentinels and effectors. Among tissues, cells of the brain and heart possess unique excitatory properties that likely demand special support. Accordingly, existing evidence demonstrates that microglia in the brain has an active role in synaptic organization, control of neuronal excitability, phagocytic removal of debris, and trophic support during brain development. In the heart, recent studies suggest that cardiac macrophages are involved in the regulation of heart homeostasis by phagocytosis, production of trophic, and immune-related factors, and by forming direct contacts with cardiomyocytes to regulate electrical conduction. In this review, we discuss mechanisms associated with the high degree of specialization of resident macrophages in both tissues, their origin and heterogeneity, and their contributions in regulating homeostasis under steady-state and pathological conditions.
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Affiliation(s)
| | - Andrés Hidalgo
- Area of Cell and Developmental Biology, Fundación CNIC, Madrid, Spain
| | - Iván Ballesteros
- Area of Cell and Developmental Biology, Fundación CNIC, Madrid, Spain
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20
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Lopez‐Atalaya JP, Askew KE, Sierra A, Gomez‐Nicola D. Development and maintenance of the brain's immune toolkit: Microglia and non-parenchymal brain macrophages. Dev Neurobiol 2018; 78:561-579. [PMID: 29030904 PMCID: PMC6001428 DOI: 10.1002/dneu.22545] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 09/29/2017] [Accepted: 10/06/2017] [Indexed: 01/10/2023]
Abstract
Microglia and non-parenchymal macrophages located in the perivascular space, the meninges and the choroid plexus are independent immune populations that play vital roles in brain development, homeostasis, and tissue healing. Resident macrophages account for a significant proportion of cells in the brain and their density remains stable throughout the lifespan thanks to constant turnover. Microglia develop from yolk sac progenitors, later evolving through intermediate progenitors in a fine-tuned process in which intrinsic factors and external stimuli combine to progressively sculpt their cell type-specific transcriptional profiles. Recent evidence demonstrates that non-parenchymal macrophages are also generated during early embryonic development. In recent years, the development of powerful fate mapping approaches combined with novel genomic and transcriptomic methodologies have greatly expanded our understanding of how brain macrophages develop and acquire specialized functions, and how cell population dynamics are regulated. Here, we review the transcription factors, epigenetic remodeling, and signaling pathways orchestrating the embryonic development of microglia and non-parenchymal macrophages. Next, we describe the dynamics of the macrophage populations of the brain and discuss the role of progenitor cells, to gain a better understanding of their functions in the healthy and diseased brain. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 561-579, 2018.
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Affiliation(s)
- Jose P. Lopez‐Atalaya
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández‐Consejo Superior de Investigaciones Científicas (UMH‐CSIC), Avenida Ramón y Cajal, s/n, Sant Joan d'AlacantSpain
| | - Katharine E. Askew
- Southampton General Hospital, Biological Sciences, University of Southampton, South Lab&Path Block, LD80C, MP840SO166YDSouthamptonUnited Kingdom
| | - Amanda Sierra
- Achucarro Basque Center for NeuroscienceLeioa48940Spain
- Ikerbasque FoundationBilbao48013Spain
- University of the Basque Country EHU/UPVLeioa48940Spain
| | - Diego Gomez‐Nicola
- Southampton General Hospital, Biological Sciences, University of Southampton, South Lab&Path Block, LD80C, MP840SO166YDSouthamptonUnited Kingdom
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21
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Siew JJ, Chern Y. Microglial Lectins in Health and Neurological Diseases. Front Mol Neurosci 2018; 11:158. [PMID: 29867350 PMCID: PMC5960708 DOI: 10.3389/fnmol.2018.00158] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 04/25/2018] [Indexed: 12/11/2022] Open
Abstract
Microglia are the innate sentinels of the central nervous system (CNS) and are responsible for the homeostasis and immune defense of the CNS. Under the influence of the local environment and cell-cell interaction, microglia exhibit a multidimensional and context-dependent phenotypes that can be cytotoxic and neuroprotective. Recent studies suggest that microglia express multitudinous types of lectins, including galectins, Siglecs, mannose-binding lectins (MBLs) and other glycan binding proteins. Because most studies that examine lectins focus on the peripheral system, the functions of lectins have not been critically investigated in the CNS. In addition, the types of brain cells that contribute to the altered levels of lectins present in diseases are often unclear. In this review, we will discuss how galectins, Siglecs, selectins and MBLs contribute to the dynamic functions of microglia. The interacting ligands of these lectins are complex glycoconjugates, which consist of glycoproteins and glycolipids that are expressed on microglia or surrounding cells. The current understanding of the heterogeneity and functions of glycans in the brain is limited. Galectins are a group of pleotropic proteins that recognize both β-galactoside-containing glycans and non- β-galactoside-containing proteins. The function and regulation of galectins have been implicated in immunomodulation, neuroinflammation, apoptosis, phagocytosis and oxidative bursts. Most Siglecs are expressed at a low level on the plasma membrane and bind to sialic acid residues for immunosurveillance and cell-cell communication. Siglecs are classified based on their inhibitory and activatory downstream signaling properties. Inhibitory Siglecs negatively regulate microglia activation upon recognizing the intact sialic acid patterns and vice versa. MBLs are expressed upon infection in cytoplasm and can be secreted in order to recognize molecules containing terminal mannose as an innate immune defense machinery. Most importantly, multiple studies have reported dysregulation of lectins in neurological disorders. Here, we reviewed recent studies on microglial lectins and their functions in CNS health and disease, and suggest that these lectin families are novel, potent therapeutic targets for neurological diseases.
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Affiliation(s)
- Jian Jing Siew
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yijuang Chern
- Taiwan International Graduate Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan.,Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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22
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Sánchez-Ramón S, Faure F. The Thymus/Neocortex Hypothesis of the Brain: A Cell Basis for Recognition and Instruction of Self. Front Cell Neurosci 2017; 11:340. [PMID: 29163052 PMCID: PMC5663735 DOI: 10.3389/fncel.2017.00340] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 10/13/2017] [Indexed: 12/18/2022] Open
Abstract
The recognition of internal and external sources of stimuli, the self from non-self, seems to be an intrinsic property to the adequate functioning of the immune system and the nervous system, both complex network systems that have evolved to safeguard the self biological identity of the organism. The mammalian brain development relies on dynamic and adaptive processes that are now well described. However, the rules dictating this highly constrained developmental process remain elusive. Here we hypothesize that there is a cellular basis for brain selfhood, based on the analogy of the global mechanisms that drive the self/non-self recognition and instruction by the immune system. In utero education within the thymus by multi-step selection processes discard overly low and high affinity T-lymphocytes to self stimuli, thus avoiding expendable or autoreactive responses that might lead to harmful autoimmunity. We argue that the self principle is one of the chief determinants of neocortical brain neurogenesis. According to our hypothesis, early-life education on self at the subcortical plate of the neocortex by selection processes might participate in the striking specificity of neuronal repertoire and assure efficiency and self tolerance. Potential implications of this hypothesis in self-reactive neurological pathologies are discussed, particularly involving consciousness-associated pathophysiological conditions, i.e., epilepsy and schizophrenia, for which we coined the term autophrenity.
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Affiliation(s)
- Silvia Sánchez-Ramón
- Department of Clinical Immunology and IdISSC, Hospital Clínico San Carlos, Madrid, Spain.,Department of Microbiology I, School of Medicine, Complutense University of Madrid, Madrid, Spain
| | - Florence Faure
- PSL Research University, INSERM U932, Institut Curie, Paris, France
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23
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Chen VS, Morrison JP, Southwell MF, Foley JF, Bolon B, Elmore SA. Histology Atlas of the Developing Prenatal and Postnatal Mouse Central Nervous System, with Emphasis on Prenatal Days E7.5 to E18.5. Toxicol Pathol 2017; 45:705-744. [PMID: 28891434 DOI: 10.1177/0192623317728134] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Evaluation of the central nervous system (CNS) in the developing mouse presents unique challenges, given the complexity of ontogenesis, marked structural reorganization over very short distances in 3 dimensions each hour, and numerous developmental events susceptible to genetic and environmental influences. Developmental defects affecting the brain and spinal cord arise frequently both in utero and perinatally as spontaneous events, following teratogen exposure, and as sequelae to induced mutations and thus are a common factor in embryonic and perinatal lethality in many mouse models. Knowledge of normal organ and cellular architecture and differentiation throughout the mouse's life span is crucial to identify and characterize neurodevelopmental lesions. By providing a well-illustrated overview summarizing major events of normal in utero and perinatal mouse CNS development with examples of common developmental abnormalities, this annotated, color atlas can be used to identify normal structure and histology when phenotyping genetically engineered mice and will enhance efforts to describe and interpret brain and spinal cord malformations as causes of mouse embryonic and perinatal lethal phenotypes. The schematics and images in this atlas illustrate major developmental events during gestation from embryonic day (E)7.5 to E18.5 and after birth from postnatal day (P)1 to P21.
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Affiliation(s)
- Vivian S Chen
- 1 Charles River Laboratories Inc., Durham, North Carolina, USA.,Authors contributed equally
| | - James P Morrison
- 2 Charles River Laboratories Inc., Shrewsbury, Massachusetts, USA.,Authors contributed equally
| | - Myra F Southwell
- 3 Cellular Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | - Julie F Foley
- 4 Bio-Molecular Screening Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
| | | | - Susan A Elmore
- 3 Cellular Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
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24
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Abstract
Neurotrophins, including nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), bind to their high-affinity receptors to promote neuronal survival during brain development. One of the key downstream pathways is the phospholipase C (PLC) pathway, which not only plays a central role in calcium release from internal store but also in activation of TRPC channels coupled with neurotrophin receptors. TRPC channels are required for the neurotrophin-mediated neuronal protective effects. In addition, activation of TRPC channels is able to protect neurons in the absence of neurotrophin. In some circumstances, TRPC channels coupled with metabotropic glutamate receptor may mediate the excitotoxicity by calcium overload. One of the key questions in the field is the channel gating mechanisms; understanding of which would help design compounds to modulate the channel properties. The development and identification of TRPC channel agonists or blockers are promising and may unveil new therapeutic drugs for the treatment of neurodegenerative diseases and epilepsy.
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25
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Almeida AS, Vieira HLA. Role of Cell Metabolism and Mitochondrial Function During Adult Neurogenesis. Neurochem Res 2016; 42:1787-1794. [DOI: 10.1007/s11064-016-2150-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/09/2016] [Accepted: 12/10/2016] [Indexed: 12/15/2022]
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26
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Abstract
For almost two decades, cell-based therapies have been tested in modern regenerative medicine to either replace or regenerate human cells, tissues, or organs and restore normal function. Secreted paracrine factors are increasingly accepted to exert beneficial biological effects that promote tissue regeneration. These factors are called the cell secretome and include a variety of proteins, lipids, microRNAs, and extracellular vesicles, such as exosomes and microparticles. The stem cell secretome has most commonly been investigated in pre-clinical settings. However, a growing body of evidence indicates that other cell types, such as peripheral blood mononuclear cells (PBMCs), are capable of releasing significant amounts of biologically active paracrine factors that exert beneficial regenerative effects. The apoptotic PBMC secretome has been successfully used pre-clinically for the treatment of acute myocardial infarction, chronic heart failure, spinal cord injury, stroke, and wound healing. In this review we describe the benefits of choosing PBMCs instead of stem cells in regenerative medicine and characterize the factors released from apoptotic PBMCs. We also discuss pre-clinical studies with apoptotic cell-based therapies and regulatory issues that have to be considered when conducting clinical trials using cell secretome-based products. This should allow the reader to envision PBMC secretome-based therapies as alternatives to all other forms of cell-based therapies.
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Affiliation(s)
- Lucian Beer
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Cardiac and Thoracic Diagnosis and Regeneration, Medical University of Vienna, Vienna, Austria
| | - Michael Mildner
- Department of Dermatology, Medical University of Vienna, Vienna, Austria
| | - Mariann Gyöngyösi
- Division of Cardiology, Medical University of Vienna, Vienna, Austria
| | - Hendrik Jan Ankersmit
- Christian Doppler Laboratory for Cardiac and Thoracic Diagnosis and Regeneration, Medical University of Vienna, Vienna, Austria.
- Head FFG Project 852748 "APOSEC", FOLAB Surgery, Medical University of Vienna, Vienna, Austria.
- Department of Thoracic Surgery, Medical University Vienna, Vienna, Austria.
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27
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Increased neuronal death and disturbed axonal growth in the Polμ-deficient mouse embryonic retina. Sci Rep 2016; 6:25928. [PMID: 27172884 PMCID: PMC4865816 DOI: 10.1038/srep25928] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 04/25/2016] [Indexed: 01/04/2023] Open
Abstract
Programmed cell death occurs naturally at different stages of neural development, including neurogenesis. The functional role of this early phase of neural cell death, which affects recently differentiated neurons among other cell types, remains undefined. Some mouse models defective in DNA double-strand break (DSB) repair present massive cell death during neural development, occasionally provoking embryonic lethality, while other organs and tissues remain unaffected. This suggests that DSBs occur frequently and selectively in the developing nervous system. We analyzed the embryonic retina of a mouse model deficient in the error-prone DNA polymerase μ (Polμ), a key component of the non-homologous end-joining (NHEJ) repair system. DNA DSBs were increased in the mutant mouse at embryonic day 13.5 (E13.5), as well as the incidence of cell death that affected young neurons, including retinal ganglion cells (RGCs). Polμ(-/-) mice also showed disturbed RGC axonal growth and navigation, and altered distribution of the axonal guidance molecules L1-CAM and Bravo (also known as Nr-CAM). These findings demonstrate that Polμ is necessary for proper retinal development, and support that the generation of DSBs and their repair via the NHEJ pathway are genuine processes involved in neural development.
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28
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Almeida AS, Soares NL, Vieira M, Gramsbergen JB, Vieira HLA. Carbon Monoxide Releasing Molecule-A1 (CORM-A1) Improves Neurogenesis: Increase of Neuronal Differentiation Yield by Preventing Cell Death. PLoS One 2016; 11:e0154781. [PMID: 27144388 PMCID: PMC4856303 DOI: 10.1371/journal.pone.0154781] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 04/19/2016] [Indexed: 11/19/2022] Open
Abstract
Cerebral ischemia and neurodegenerative diseases lead to impairment or death of neurons in the central nervous system. Stem cell based therapies are promising strategies currently under investigation. Carbon monoxide (CO) is an endogenous product of heme degradation by heme oxygenase (HO) activity. Administration of CO at low concentrations produces several beneficial effects in distinct tissues, namely anti-apoptotic and anti-inflammatory. Herein the CO role on modulation of neuronal differentiation was assessed. Three different models with increasing complexity were used: human neuroblastoma SH-S5Y5 cell line, human teratocarcinoma NT2 cell line and organotypic hippocampal slice cultures (OHSC). Cell lines were differentiated into post-mitotic neurons by treatment with retinoic acid (RA) supplemented with CO-releasing molecule A1 (CORM-A1). CORM-A1 positively modulated neuronal differentiation, since it increased final neuronal production and enhanced the expression of specific neuronal genes: Nestin, Tuj1 and MAP2. Furthermore, during neuronal differentiation process, there was an increase in proliferative cell number (ki67 mRNA expressing cells) and a decrease in cell death (lower propidium iodide (PI) uptake, limitation of caspase-3 activation and higher Bcl-2 expressing cells). CO supplementation did not increase the expression of RA receptors. In the case of SH-S5Y5 model, small amounts of reactive oxygen species (ROS) generation emerges as important signaling molecules during CO-promoted neuronal differentiation. CO's improvement of neuronal differentiation yield was validated using OHSC as ex vivo model. CORM-A1 treatment of OHSC promoted higher levels of cells expressing the neuronal marker Tuj1. Still, CORM-A1 increased cell proliferation assessed by ki67 expression and also prevented cell death, which was followed by increased Bcl-2 expression, decreased levels of active caspase-3 and PI uptake. Likewise, ROS signaling emerged as key factors in CO's increasing number of differentiated neurons in OHSC. In conclusion, CO's increasing number of differentiated neurons is a novel biological role disclosed herein. CO improves neuronal yield due to its capacity to reduce cell death, promoting an increase in proliferative population. However, one cannot disregard a direct CO's effect on specific cellular processes of neuronal differentiation. Further studies are needed to evaluate how CO can potentially modulate cell mechanisms involved in neuronal differentiation. In summary, CO appears as a promising therapeutic molecule to stimulate endogenous neurogenesis or to improve in vitro neuronal production for cell therapy strategies.
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Affiliation(s)
- Ana S. Almeida
- CEDOC, Faculdade de Ciência Médicas, Universidade Nova de Lisboa, 1169-056, Lisboa, Portugal
- Instituto de Tecnologia Química e Biológica (ITQB), Universidade Nova de Lisboa, Apartado 127, 2781-901 Oeiras, Portugal
- Instituto de Biologia Experimental e Tecnológica (iBET), Apartado 12, 2781-901 Oeiras, Portugal
| | - Nuno L. Soares
- CEDOC, Faculdade de Ciência Médicas, Universidade Nova de Lisboa, 1169-056, Lisboa, Portugal
| | - Melissa Vieira
- CEDOC, Faculdade de Ciência Médicas, Universidade Nova de Lisboa, 1169-056, Lisboa, Portugal
| | - Jan Bert Gramsbergen
- Institute of Molecular Medicine, University of Southern Denmark, Winsløwparken 21, DK-5000 Odense C, Denmark
| | - Helena L. A. Vieira
- CEDOC, Faculdade de Ciência Médicas, Universidade Nova de Lisboa, 1169-056, Lisboa, Portugal
- Instituto de Biologia Experimental e Tecnológica (iBET), Apartado 12, 2781-901 Oeiras, Portugal
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29
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Xavier AL, Menezes JRL, Goldman SA, Nedergaard M. Fine-tuning the central nervous system: microglial modelling of cells and synapses. Philos Trans R Soc Lond B Biol Sci 2015; 369:20130593. [PMID: 25225087 DOI: 10.1098/rstb.2013.0593] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Microglia constitute as much as 10-15% of all cells in the mammalian central nervous system (CNS) and are the only glial cells that do not arise from the neuroectoderm. As the principal CNS immune cells, microglial cells represent the first line of defence in response to exogenous threats. Past studies have largely been dedicated to defining the complex immune functions of microglial cells. However, our understanding of the roles of microglia has expanded radically over the past years. It is now clear that microglia are critically involved in shaping neural circuits in both the developing and adult CNS, and in modulating synaptic transmission in the adult brain. Intriguingly, microglial cells appear to use the same sets of tools, including cytokine and chemokine release as well as phagocytosis, whether modulating neural function or mediating the brain's innate immune responses. This review will discuss recent developments that have broadened our views of neuro-glial signalling to include the contribution of microglial cells.
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Affiliation(s)
- Anna L Xavier
- Laboratório de Neuroanatomia Celular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941-902, Brazil Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, NY 14642, USA
| | - João R L Menezes
- Laboratório de Neuroanatomia Celular, Instituto de Ciências Biomédicas, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Steven A Goldman
- Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, NY 14642, USA
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Noguchi KK, Cabrera OH, Swiney BS, Salinas-Contreras P, Smith JK, Farber NB. Hedgehog regulates cerebellar progenitor cell and medulloblastoma apoptosis. Neurobiol Dis 2015; 83:35-43. [PMID: 26319366 DOI: 10.1016/j.nbd.2015.08.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/12/2015] [Accepted: 08/19/2015] [Indexed: 12/12/2022] Open
Abstract
The external granule layer (EGL) is a proliferative region that produces over 90% of the neurons in the cerebellum but can also malignantly transform into a cerebellar tumor called the medulloblastoma (the most common malignant brain tumor in children). Current dogma considers Hedgehog stimulation a potent proliferative signal for EGL neural progenitor cells (NPCs) and medulloblastomas. However, the Hedgehog pathway also acts as a survival signal in the neural tube where it regulates dorsoventral patterning by controlling NPC apoptosis. Here we show that Hedgehog stimulation is also a potent survival signal in the EGL and medulloblastomas that produces a massive apoptotic response within hours of signal loss in mice. This toxicity can be produced by numerous Hedgehog antagonists (vismodegib, cyclopamine, and jervine) and is Bax/Bak dependent but p53 independent. Finally, since glucocorticoids can also induce EGL and medulloblastoma apoptosis, we show that Hedgehog's effects on apoptosis can occur independent of glucocorticoid stimulation. This effect may play a major role in cerebellar development by directing where EGL proliferation occurs thereby morphologically sculpting growth. It may also be a previously unknown major therapeutic effect of Hedgehog antagonists during medulloblastoma therapy. Results are discussed in terms of their implications for both cerebellar development and medulloblastoma treatment.
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Affiliation(s)
- Kevin Kiyoshi Noguchi
- Washington University in St. Louis, Department of Psychiatry, 660 South Euclid, St. Louis, MO 63110, USA.
| | - Omar Hoseá Cabrera
- University of Missouri-St. Louis, Department of Psychological Sciences, One University Boulevard, 325 Stadler Hall, St. Louis, MO 63121, USA.
| | - Brant S Swiney
- Washington University in St. Louis, Department of Psychiatry, 660 South Euclid, St. Louis, MO 63110, USA.
| | - Patricia Salinas-Contreras
- Washington University in St. Louis, Department of Psychiatry, 660 South Euclid, St. Louis, MO 63110, USA.
| | - Julie Kathryn Smith
- Washington University in St. Louis, Department of Psychiatry, 660 South Euclid, St. Louis, MO 63110, USA.
| | - Nuri B Farber
- Washington University in St. Louis, Department of Psychiatry, 660 South Euclid, St. Louis, MO 63110, USA.
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Chung KM, Park H, Jung S, Ha S, Yoo SJ, Woo H, Lee HJ, Kim SW, Kim EK, Moon C, Yu SW. Calpain Determines the Propensity of Adult Hippocampal Neural Stem Cells to Autophagic Cell Death Following Insulin Withdrawal. Stem Cells 2015; 33:3052-64. [DOI: 10.1002/stem.2082] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/12/2015] [Accepted: 05/23/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Kyung Min Chung
- Department of Brain and Cognitive Sciences; Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
| | - Hyunhee Park
- Department of Brain and Cognitive Sciences; Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
| | - Seonghee Jung
- Department of Brain and Cognitive Sciences; Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
| | - Shinwon Ha
- Department of Brain and Cognitive Sciences; Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
| | - Seung-Jun Yoo
- Department of Brain and Cognitive Sciences; Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
| | - Hanwoong Woo
- Department of Brain and Cognitive Sciences; Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
| | - Hyang Ju Lee
- Department of Biochemistry and Molecular Biology; Asan Medical Center, University of Ulsan College of Medicine; Seoul Republic of Korea
| | - Seong Who Kim
- Department of Biochemistry and Molecular Biology; Asan Medical Center, University of Ulsan College of Medicine; Seoul Republic of Korea
| | - Eun-Kyoung Kim
- Department of Brain and Cognitive Sciences; Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
- Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
| | - Cheil Moon
- Department of Brain and Cognitive Sciences; Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
- Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
| | - Seong-Woon Yu
- Department of Brain and Cognitive Sciences; Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
- Neurometabolomics Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST); Daegu Republic of Korea
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Abstract
Microglia are macrophages that colonize the brain during development to establish a resident population of professional phagocytes that protect against invading pathogens and contribute to brain development and homeostasis. As such, these cells sit at the interface between immunology and neurobiology. In addition to their key roles in brain physiology, microglia offer a great opportunity to address central questions in biology relating to how migrating cells find their positions in the embryo, adopt a behavior that is appropriate for that position, and interact with their local environment. We aim, in this review, to survey key recent advances in microglial research.
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Affiliation(s)
- Alessandra Maria Casano
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Francesca Peri
- European Molecular Biology Laboratory, Developmental Biology Unit, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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Amelioration of Auditory Response by DA9801 in Diabetic Mouse. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:230747. [PMID: 25878713 PMCID: PMC4387908 DOI: 10.1155/2015/230747] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/04/2015] [Accepted: 03/10/2015] [Indexed: 12/04/2022]
Abstract
Diabetes mellitus (DM) is a metabolic disease that involves disorders such as diabetic retinopathy, diabetic neuropathy, and diabetic hearing loss. Recently, neurotrophin has become a treatment target that has shown to be an attractive alternative in recovering auditory function altered by DM. The aim of this study was to evaluate the effect of DA9801, a mixture of Dioscorea nipponica and Dioscorea japonica extracts, in the auditory function damage produced in a STZ-induced diabetic model and to provide evidence of the mechanisms involved in enhancing these protective effects. We found a potential application of DA9801 on hearing impairment in the STZ-induced diabetic model, demonstrated by reducing the deterioration produced by DM in ABR threshold in response to clicks and normalizing wave I–IV latencies and Pa latencies in AMLR. We also show evidence that these effects might be elicited by inducing NGF related through Nr3c1 and Akt. Therefore, this result suggests that the neuroprotective effects of DA9801 on the auditory damage produced by DM may be affected by NGF increase resulting from Nr3c1 via Akt transformation.
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34
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Juraver-Geslin HA, Durand BC. Early development of the neural plate: new roles for apoptosis and for one of its main effectors caspase-3. Genesis 2015; 53:203-24. [PMID: 25619400 DOI: 10.1002/dvg.22844] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 01/07/2015] [Indexed: 12/12/2022]
Abstract
Despite its tremendous complexity, the vertebrate nervous system emerges from a homogenous layer of neuroepithelial cells, the neural plate. Its formation relies on the time- and space-controlled progression of developmental programs. Apoptosis is a biological process that removes superfluous and potentially dangerous cells and is implemented through the activation of a molecular pathway conserved during evolution. Apoptosis and an unconventional function of one of its main effectors, caspase-3, contribute to the patterning and growth of the neuroepithelium. Little is known about the intrinsic and extrinsic cues controlling activities of the apoptotic machinery during development. The BarH-like (Barhl) proteins are homeodomain-containing transcription factors. The observations in Caenorhabditis elegans, Xenopus, and mice document that Barhl proteins act in cell survival and as cell type-specific regulators of a caspase-3 function that limits neural progenitor proliferation. In this review, we discuss the roles and regulatory modes of the apoptotic machinery in the development of the neural plate. We focus on the Barhl2, the Sonic Hedgehog, and the Wnt pathways and their activities in neural progenitor survival and proliferation.
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Affiliation(s)
- Hugo A Juraver-Geslin
- Department of Basic Science, Craniofacial Biology, College of Dentistry, New York University, New York, New York
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35
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Azzarelli R, Kerloch T, Pacary E. Regulation of cerebral cortex development by Rho GTPases: insights from in vivo studies. Front Cell Neurosci 2015; 8:445. [PMID: 25610373 PMCID: PMC4285737 DOI: 10.3389/fncel.2014.00445] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 12/11/2014] [Indexed: 12/31/2022] Open
Abstract
The cerebral cortex is the site of higher human cognitive and motor functions. Histologically, it is organized into six horizontal layers, each containing unique populations of molecularly and functionally distinct excitatory projection neurons and inhibitory interneurons. The stereotyped cellular distribution of cortical neurons is crucial for the formation of functional neural circuits and it is predominantly established during embryonic development. Cortical neuron development is a multiphasic process characterized by sequential steps of neural progenitor proliferation, cell cycle exit, neuroblast migration and neuronal differentiation. This series of events requires an extensive and dynamic remodeling of the cell cytoskeleton at each step of the process. As major regulators of the cytoskeleton, the family of small Rho GTPases has been shown to play essential functions in cerebral cortex development. Here we review in vivo findings that support the contribution of Rho GTPases to cortical projection neuron development and we address their involvement in the etiology of cerebral cortex malformations.
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Affiliation(s)
- Roberta Azzarelli
- Department of Oncology, Hutchison/MRC Research Centre, Cambridge Biomedical Campus, University of Cambridge Cambridge, UK
| | - Thomas Kerloch
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie Bordeaux, France ; Institut National de la Santé et de la Recherche Médicale, Physiopathologie de la Plasticité Neuronale, Université de Bordeaux Bordeaux, France
| | - Emilie Pacary
- Institut National de la Santé et de la Recherche Médicale U862, Neurocentre Magendie Bordeaux, France ; Institut National de la Santé et de la Recherche Médicale, Physiopathologie de la Plasticité Neuronale, Université de Bordeaux Bordeaux, France
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36
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Flow cytometric analysis of DNA synthesis and apoptosis in central nervous system using fresh cell nuclei. Methods Mol Biol 2015; 1254:33-42. [PMID: 25431055 DOI: 10.1007/978-1-4939-2152-2_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The use of flow cytometry in vertebrate nervous tissues is hampered by the morphological complexity and high level of interconnectivity intrinsic to their cellular constituents. Here we describe a simplified procedure for the identification and quantitative analysis of neural cells by flow cytometry based on the isolation and immunolabeling of fresh cell nuclei. We have applied this procedure for the quantitative analysis of apoptosis and DNA synthesis in the embryonic brain.
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37
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Moreno E, Rhiner C. Darwin's multicellularity: from neurotrophic theories and cell competition to fitness fingerprints. Curr Opin Cell Biol 2014; 31:16-22. [PMID: 25022356 PMCID: PMC4238900 DOI: 10.1016/j.ceb.2014.06.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 06/16/2014] [Accepted: 06/19/2014] [Indexed: 12/15/2022]
Abstract
Metazoans have evolved ways to engage only the most appropriate cells for long-term tissue development and homeostasis. In many cases, competitive interactions have been shown to guide such cell selection events. In Drosophila, a process termed cell competition eliminates slow proliferating cells from growing epithelia. Recent studies show that cell competition is conserved in mammals with crucial functions like the elimination of suboptimal stem cells from the early embryo and the replacement of old T-cell progenitors in the thymus to prevent tumor formation. Moreover, new data in Drosophila has revealed that fitness indicator proteins, required for cell competition, are also involved in the culling of retinal neurons suggesting that 'fitness fingerprints' may play a general role in cell selection.
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Affiliation(s)
- Eduardo Moreno
- Institute of Cell Biology, IZB, University of Bern, Bern CH-3012, Switzerland.
| | - Christa Rhiner
- Institute of Cell Biology, IZB, University of Bern, Bern CH-3012, Switzerland.
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38
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Perillo M, Arnone MI. Characterization of insulin-like peptides (ILPs) in the sea urchin Strongylocentrotus purpuratus: insights on the evolution of the insulin family. Gen Comp Endocrinol 2014; 205:68-79. [PMID: 24971803 DOI: 10.1016/j.ygcen.2014.06.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 06/10/2014] [Accepted: 06/15/2014] [Indexed: 11/21/2022]
Abstract
The evolutionary history of the insulin-like peptides (ILPs), members of the insulin family, is still a matter of debate. Although ILPs structure and expression have been described in different metazoans, little is known about these molecules in non-chordate deuterostomes, such as the echinoderms. In order to fill this gap in the current literature, we have characterized two members of the insulin family found in the sea urchin Strongylocentrotus purpuratus genome (SpIgf1 and SpIgf2 that, after our analysis, we suggest to rename SpILP1 and SpILP2, respectively) together with their putative receptor (SpInsr). We found that SpILP1 gene structure is more similar to the cephalochordate amphioxus ILP, while the SpILP2 gene shows a completely different organization. In addition, we have revealed that SpILP1 and SpILP2 transcripts are expressed in different compartments during embryo/larva development and that the SpILP1 protein mature form differs in the egg and the larva, suggesting different biological roles. Finally, we have analyzed SpILP1 transcript and protein expression in response to different feeding regimes through real-time quantitative PCR, Western blot and immunohistochemistry methodologies, and found that its expression and localization are feeding-dependent. We discuss our findings in a comparative evolutionary perspective including data available in other animal models and provide new insights into the evolution of the insulin family molecules. In the model we put forward, the last common ancestor of all deuterostomes presented an ILP composed of the B-C-A-D-E domains, and successive lineage specific independent gene duplication events resulted in the presence of several ILPs in vertebrates and in echinoderms.
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Affiliation(s)
- Margherita Perillo
- Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Napoli, Italy
| | - Maria Ina Arnone
- Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, Napoli, Italy.
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39
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Francisco-Morcillo J, Bejarano-Escobar R, Rodríguez-León J, Navascués J, Martín-Partido G. Ontogenetic cell death and phagocytosis in the visual system of vertebrates. Dev Dyn 2014; 243:1203-25. [PMID: 25130286 DOI: 10.1002/dvdy.24174] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 07/04/2014] [Accepted: 07/25/2014] [Indexed: 12/25/2022] Open
Abstract
Programmed cell death (PCD), together with cell proliferation, cell migration, and cell differentiation, is an essential process during development of the vertebrate nervous system. The visual system has been an excellent model on which to investigate the mechanisms involved in ontogenetic cell death. Several phases of PCD have been reported to occur during visual system ontogeny. During these phases, comparative analyses demonstrate that dying cells show similar but not identical spatiotemporally restricted patterns in different vertebrates. Additionally, the chronotopographical coincidence of PCD with the entry of specialized phagocytes in some regions of the developing vertebrate visual system suggests that factors released from degenerating cells are involved in the cell migration of macrophages and microglial cells. Contradicting this hypothesis however, in many cases the cell corpses generated during degeneration are rapidly phagocytosed by neighboring cells, such as neuroepithelial cells or Müller cells. In this review, we describe the occurrence and the sites of PCD during the morphogenesis and differentiation of the retina and optic pathways of different vertebrates, and discuss the possible relationship between PCD and phagocytes during ontogeny.
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40
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Cohen G, Ettinger K, Lecht S, Lelkes PI, Lazarovici P. Transcriptional Down-regulation of Epidermal Growth Factor (EGF) Receptors by Nerve Growth Factor (NGF) in PC12 Cells. J Mol Neurosci 2014; 54:574-85. [DOI: 10.1007/s12031-014-0388-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Accepted: 07/22/2014] [Indexed: 12/14/2022]
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41
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Barton A, Fendrik AJ, Rotondo E. A stochastic model of neurogenesis controlled by a single factor. J Theor Biol 2014; 355:77-82. [PMID: 24721477 DOI: 10.1016/j.jtbi.2014.03.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 03/17/2014] [Accepted: 03/31/2014] [Indexed: 10/25/2022]
Abstract
The researches on cortical neurogenesis reveal that asymmetric division plays a key role in controlling the balance between the self-renewal of stem cells and the beginning of the neural differentiation. In such a process a neural stem cell divides by mitosis, originating a postmitotic neuron and other pluripotent stem cell available for subsequent differentiation events. In addition, studies of cell lineage trees of cultured neural progenitors reveal tree shapes and subtrees recurrent, consistent with a stochastic model of division symmetrical/asymmetrical. These considerations have led us to develop a stochastic model of neurogenesis in order to explore the possibility that this is controlled primarily by a single factor (i.e. the concentration of mNumb in the cell). We contrast the predictions of our model with experimental data and compare it with other models of neurogenesis.
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Affiliation(s)
- A Barton
- Instituto de Ciencias, Universidad Nacional de General Sarmiento, J.M. Gutierrez 1150, 1613 Los Polvorines, Buenos Aires, Argentina.
| | - A J Fendrik
- Instituto de Ciencias, Universidad Nacional de General Sarmiento, J.M. Gutierrez 1150, 1613 Los Polvorines, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina.
| | - E Rotondo
- Instituto de Ciencias, Universidad Nacional de General Sarmiento, J.M. Gutierrez 1150, 1613 Los Polvorines, Buenos Aires, Argentina.
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42
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Noguchi KK. Glucocorticoid Induced Cerebellar Toxicity in the Developing Neonate: Implications for Glucocorticoid Therapy during Bronchopulmonary Dysplasia. Cells 2014; 3:36-52. [PMID: 24501683 PMCID: PMC3910303 DOI: 10.3390/cells3010036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Prematurely born infants commonly suffer respiratory dysfunction due to the immature state of their lungs. As a result, clinicians often administer glucocorticoid (GC) therapy to accelerate lung maturation and reduce inflammation. Unfortunately, several studies have found GC therapy can also produce neuromotor/cognitive deficits and selectively stunt the cerebellum. However, despite its continued use, relatively little is known about how exposure to this hormone might produce neurodevelopmental deficits. In this review, we use rodent and human research to provide evidence that GC therapy may disrupt cerebellar development through the rapid induction of apoptosis in the cerebellar external granule layer (EGL). The EGL is a transient proliferative region responsible for the production of over 90% of the neurons in the cerebellum. During normal development, endogenous GC stimulation is thought to selectively signal the elimination of the EGL once production of new neurons is complete. As a result, GC therapy may precociously eliminate the EGL before it can produce enough neurons for normal cerebellar function. It is hoped that this review may provide information for future clinical research in addition to translational guidance for the safer use of GC therapy.
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Affiliation(s)
- Kevin K Noguchi
- Department of Psychiatry, School of Medicine, Washington University in St. Louis, 660 South Euclid, Box #8134, St. Louis, MO 63110, USA; Tel.: +1-314-362-7007
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43
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Abstract
Mammalian neural stem cells (NSCs) are of particular interest because of their role in brain development and function. Recent findings suggest the intimate involvement of programmed cell death (PCD) in the turnover of NSCs. However, the underlying mechanisms of PCD are largely unknown. Although apoptosis is the best-defined form of PCD, accumulating evidence has revealed a wide spectrum of PCD encompassing apoptosis, autophagic cell death (ACD) and necrosis. This mini-review aims to illustrate a unique regulation of PCD in NSCs. The results of our recent studies on autophagic death of adult hippocampal neural stem (HCN) cells are also discussed. HCN cell death following insulin withdrawal clearly provides a reliable model that can be used to analyze the molecular mechanisms of ACD in the larger context of PCD. More research efforts are needed to increase our understanding of the molecular basis of NSC turnover under degenerating conditions, such as aging, stress and neurological diseases. Efforts aimed at protecting and harnessing endogenous NSCs will offer novel opportunities for the development of new therapeutic strategies for neuropathologies.
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Affiliation(s)
- Kyung Min Chung
- Department of Brain Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, Korea
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44
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Nguyen-Ba-Charvet KT, Chédotal A. Development of retinal layers. C R Biol 2014; 337:153-9. [PMID: 24702841 DOI: 10.1016/j.crvi.2013.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 11/28/2013] [Indexed: 11/26/2022]
Abstract
A noticeable characteristic of nervous systems is the arrangement of synapses into distinct layers. Such laminae are fundamental for the spatial organisation of synaptic connections transmitting different kinds of information. A major example of this is the inner plexiform layer (IPL) of the vertebrate retina, which is subdivided into at least ten sublayers. Another noticeable characteristic of these retina layers is that neurons are displayed in the horizontal plane in a non-random array termed as mosaic patterning. Recent studies of vertebrate and invertebrate systems have identified molecules that mediate these interactions. Here, we review the last mechanisms and molecules mediating retinal layering.
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Affiliation(s)
- Kim Tuyen Nguyen-Ba-Charvet
- Institut national de la santé et de la recherche médicale, UMR S968, CNRS UMR 7210, Université Pierre et Marie Curie (Paris-6), Institut de la vision, 17, rue Moreau, 75012 Paris, France
| | - Alain Chédotal
- Institut national de la santé et de la recherche médicale, UMR S968, CNRS UMR 7210, Université Pierre et Marie Curie (Paris-6), Institut de la vision, 17, rue Moreau, 75012 Paris, France.
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45
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Intrinsic noise induces critical behavior in leaky Markovian networks leading to avalanching. PLoS Comput Biol 2014; 10:e1003411. [PMID: 24415927 PMCID: PMC3886886 DOI: 10.1371/journal.pcbi.1003411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 11/05/2013] [Indexed: 12/02/2022] Open
Abstract
The role intrinsic statistical fluctuations play in creating avalanches – patterns of complex bursting activity with scale-free properties – is examined in leaky Markovian networks. Using this broad class of models, we develop a probabilistic approach that employs a potential energy landscape perspective coupled with a macroscopic description based on statistical thermodynamics. We identify six important thermodynamic quantities essential for characterizing system behavior as a function of network size: the internal potential energy, entropy, free potential energy, internal pressure, pressure, and bulk modulus. In agreement with classical phase transitions, these quantities evolve smoothly as a function of the network size until a critical value is reached. At that value, a discontinuity in pressure is observed that leads to a spike in the bulk modulus demarcating loss of thermodynamic robustness. We attribute this novel result to a reallocation of the ground states (global minima) of the system's stationary potential energy landscape caused by a noise-induced deformation of its topographic surface. Further analysis demonstrates that appreciable levels of intrinsic noise can cause avalanching, a complex mode of operation that dominates system dynamics at near-critical or subcritical network sizes. Illustrative examples are provided using an epidemiological model of bacterial infection, where avalanching has not been characterized before, and a previously studied model of computational neuroscience, where avalanching was erroneously attributed to specific neural architectures. The general methods developed here can be used to study the emergence of avalanching (and other complex phenomena) in many biological, physical and man-made interaction networks. Networks of noisy interacting components arise in diverse scientific disciplines. Here, we develop a mathematical framework to study the underlying causes of a bursting phenomenon in network activity known as avalanching. As prototypical examples, we study a model of disease spreading in a population of individuals and a model of brain activity in a neural network. Although avalanching is well-documented in neural networks, thought to be crucial for learning, information processing, and memory, it has not been studied before in disease spreading. We employ tools originally used to analyze thermodynamic systems to argue that randomness in the actions of individual network components plays a fundamental role in avalanche formation. We show that avalanching is a spontaneous behavior, brought about by a phenomenon reminiscent to a phase transition in statistical mechanics, caused by increasing randomness as the network size decreases. Our work demonstrates that a previously suggested balanced feed-forward network structure is not necessary for neuronal avalanching. Instead, we attribute avalanching to a reallocation of the global minima of the network's stationary potential energy landscape, caused by a noise-induced deformation of its topographic surface.
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Shirazi Fard S, All-Ericsson C, Hallböök F. The heterogenic final cell cycle of chicken retinal Lim1 horizontal cells is not regulated by the DNA damage response pathway. Cell Cycle 2013; 13:408-17. [PMID: 24247150 DOI: 10.4161/cc.27200] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cells with aberrations in chromosomal ploidy are normally removed by apoptosis. However, aneuploid neurons have been shown to remain functional and active both in the cortex and in the retina. Lim1 horizontal progenitor cells in the chicken retina have a heterogenic final cell cycle, producing some cells that enter S-phase without proceeding into M-phase. The cells become heteroploid but do not undergo developmental cell death. This prompted us to investigate if the final cell cycle of these cells is under the regulation of an active DNA damage response. Our results show that the DNA damage response pathway, including γ-H2AX and Rad51 foci, is not triggered during any phase of the different final cell cycles of horizontal progenitor cells. However, chemically inducing DNA adducts or double-strand breaks in Lim1 horizontal progenitor cells activated the DNA damage response pathway, showing that the cells are capable of a functional response to DNA damage. Moreover, manipulation of the DNA damage response pathway during the final cell cycle using inhibitors of ATM/ATR, Chk1/2, and p38MAPK, neither induced apoptosis nor mitosis in the Lim1 horizontal progenitor cells. We conclude that the DNA damage response pathway is functional in the Lim1 horizontal progenitor cells, but that it is not directly involved in the regulation of the final cell cycle that gives rise to the heteroploid horizontal cell population.
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Affiliation(s)
| | | | - Finn Hallböök
- Department of Neuroscience; BMC Uppsala University; Uppsala, Sweden
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Park S. Brain-Region Specific Apoptosis Triggered by Eph/ephrin Signaling. Exp Neurobiol 2013; 22:143-8. [PMID: 24167409 PMCID: PMC3807001 DOI: 10.5607/en.2013.22.3.143] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 09/11/2013] [Accepted: 09/11/2013] [Indexed: 11/19/2022] Open
Abstract
Eph receptors and their ligands, ephrins, are abundantly expressed in neuroepithelial cells of the early embryonic brain. Overstimulation of Eph signaling in vivo increases apoptotic cell death of neuroepithelial cells, whereas null mutation of the Eph gene leads to the development of a larger brain during embryogenesis. Thus, it appears that Eph-ephrin signaling plays a role in regulating apoptotic cell death of neuroepithelial cells, thereby influencing brain size during embryonic development. Interestingly, Eph-ephrin signaling is bi-directional, with forward signaling from ephrin- to Eph-expressing cells and reverse signaling from Eph- to ephrin-expressing cells. However, it is not clear whether this forward or reverse signaling plays a role in regulating the size of the neuroepithelial cell population during early brain development. Also, Eph receptors and their corresponding ligands are mutually exclusive in their expression domains, and they encounter each other only at interfaces between their expression domains. This expression pattern may be a critical mechanism for preventing overstimulation of Eph-ephrin signaling. Nevertheless, Eph receptors are co-expressed with their corresponding ligands in certain brain regions. Recently, two studies demonstrated that brain region-specific apoptosis may be triggered by the overlapping expression of Eph and ephrin, a theme that will be explored in this mini-review.
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Affiliation(s)
- Soochul Park
- Department of Biological Science, Sookmyung Women's University, Seoul 140-742, Korea
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48
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Phagocyte dysfunction, tissue aging and degeneration. Ageing Res Rev 2013; 12:1005-12. [PMID: 23748186 DOI: 10.1016/j.arr.2013.05.006] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 05/28/2013] [Indexed: 12/11/2022]
Abstract
Immunologically-silent phagocytosis of apoptotic cells is critical to maintaining tissue homeostasis and innate immune balance. Aged phagocytes reduce their functional activity, leading to accumulation of unphagocytosed debris, chronic sterile inflammation and exacerbation of tissue aging and damage. Macrophage dysfunction plays an important role in immunosenescence. Microglial dysfunction has been linked to age-dependent neurodegenerations. Retinal pigment epithelial (RPE) cell dysfunction has been implicated in the pathogenesis of age-related macular degeneration (AMD). Despite several reports on the characterization of aged phagocytes, the role of phagocyte dysfunction in tissue aging and degeneration is yet to be fully appreciated. Lack of knowledge of molecular mechanisms by which aging reduces phagocyte function has hindered our capability to exploit the therapeutic potentials of phagocytosis for prevention or delay of tissue degeneration. This review summarizes our current knowledge of phagocyte dysfunction in aged tissues and discusses possible links to age-related diseases. We highlight the challenges to decipher the molecular mechanisms, present new research approaches and envisage future strategies to prevent phagocyte dysfunction, tissue aging and degeneration.
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Zemianek JM, Lee S, Shea TB. Acceleration of myofiber formation in culture by a digitized synaptic signal. Tissue Eng Part A 2013; 19:2693-702. [PMID: 23859139 DOI: 10.1089/ten.tea.2012.0619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Developing myofibers require chemical and electrical stimulation to induce functional muscle tissue. Tissue engineering protocols utilize either or both of these to initiate differentiation ex vivo. Current methodologies typically deliver multi-volt electrical signals, which may be hazardous to developing tissues. In attempts to mimic in vivo muscle development, we stimulated cultured muscle precursor cells with a low-voltage (1 mV) digitized synaptic signal derived from cultured cortical neurons. This synaptic signal induced larger and more adherent myofibers, along with markers of myoblast differentiation, compared to those induced following stimulation with a conventional (28 V) square signal. These findings suggest that stimulation with a digitized synaptic signal may be useful in tissue engineering and physical therapy.
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Affiliation(s)
- Jill M Zemianek
- Department of Biological Sciences, Center for Cellular Neurobiology and Neurodegeneration Research, University of Massachusetts at Lowell , Lowell, Massachusetts
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Lee H, Park E, Kim Y, Park S. EphrinA5-EphA7 complex induces apoptotic cell death via TNFR1. Mol Cells 2013; 35:450-5. [PMID: 23657875 PMCID: PMC3887865 DOI: 10.1007/s10059-013-0072-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 03/14/2013] [Accepted: 03/14/2013] [Indexed: 10/26/2022] Open
Abstract
A previous study showed that the EphA7 receptor regulates apoptotic cell death during early brain development. In this study, we provide evidence that the EphA7 receptor interacts with death receptors such as tumor necrosis factor receptor 1 (TNFR1) to decrease cell viability. We showed that ephrinA5 stimulates EphA7 to activate the TNFR1-mediated apoptotic signaling pathway. In addition, a pull-down assay using biotinylated ephrinA5-Fc revealed that ephrinA5-EphA7 complexes recruit TNFR1 to form a multi-protein complex. Immunocytochemical staining analysis showed that EphA7 was co-localized with TNFR1 on the cell surface when cells were incubated with ephrinA5 at low temperatures. Finally, both the internalization motif and death domain of TNFR1 was important for interacting with an intracytoplasmic region of EphA7; this interaction was essential for inducing the apoptotic signaling cascade. This result suggests that a distinct multi-protein complex comprising ephrinA5, EphA7, and TNFR1 may constitute a platform for inducing caspase-dependent apoptotic cell death.
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Affiliation(s)
- Haeryung Lee
- Department of Biological Science, Sookmyung Women’s University, Seoul 140-742,
Korea
| | - Eunjeong Park
- Department of Biological Science, Sookmyung Women’s University, Seoul 140-742,
Korea
| | - Yujin Kim
- Department of Biological Science, Sookmyung Women’s University, Seoul 140-742,
Korea
| | - Soochul Park
- Department of Biological Science, Sookmyung Women’s University, Seoul 140-742,
Korea
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