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Einspieler C, Prayer D, Marschik PB. Fetal movements: the origin of human behaviour. Dev Med Child Neurol 2021; 63:1142-1148. [PMID: 33973235 DOI: 10.1111/dmcn.14918] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/15/2021] [Indexed: 02/01/2023]
Abstract
The study of the onset and ontogeny of human behaviour has made it clear that a multitude of fetal movement patterns are spontaneously generated, and that there is a close association between activity and the development of peripheral and central structures. The embryo starts moving by 7.5 week's gestation; 2 to 3 weeks later, a number of movement patterns including general movements, isolated limb and head movements, hiccup, and breathing movements, appear. Some movements (e.g. yawning, smiling, 'pointing'; we show these in eight videos in this review) precede life-long patterns; others have intrauterine functions, such as sucking/swallowing for amniotic fluid regulation, breathing movements for lung development, or eye movements for retinal cell diversity. In cases of developmental brain dysfunction, fetal general movements alter their sequence and gestalt, which suggests a dysfunction of the developing nervous system. The scarcity of longitudinal studies calls for further comprehensive research on the predictive value of prenatal functional deviations. What this paper adds Motor output can occur in the absence of sensory input. Structural development is activity-dependent. Fetal general movements are among the first movement patterns to occur. Pregnancy-related and maternal factors impact quantity and modulation of fetal general movements. Prenatal general movement assessment has not yet brought the expected breakthrough.
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Affiliation(s)
- Christa Einspieler
- Research Unit iDN, Interdisciplinary Developmental Neuroscience, Division of Phoniatrics, Medical University of Graz, Graz, Austria
| | - Daniela Prayer
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Peter B Marschik
- Research Unit iDN, Interdisciplinary Developmental Neuroscience, Division of Phoniatrics, Medical University of Graz, Graz, Austria.,Child and Adolescent Psychiatry and Psychotherapy, University Medical Center Göttingen and LeibnizScience Campus Primate Cognition, Göttingen, Germany.,Department of Women's and Children's Health, Center of Neurodevelopmental Disorders (KIND), Karolinska Institutet, Stockholm, Sweden
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2
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Mukaigasa K, Sakuma C, Okada T, Homma S, Shimada T, Nishiyama K, Sato N, Yaginuma H. Motor neurons with limb-innervating character in the cervical spinal cord are sculpted by apoptosis based on the Hox code in chick embryo. Development 2017; 144:4645-4657. [PMID: 29061638 DOI: 10.1242/dev.158873] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/16/2017] [Indexed: 12/13/2022]
Abstract
In the developing chick embryo, a certain population of motor neurons (MNs) in the non-limb-innervating cervical spinal cord undergoes apoptosis between embryonic days 4 and 5. However, the characteristics of these apoptotic MNs remain undefined. Here, by examining the spatiotemporal profiles of apoptosis and MN subtype marker expression in normal or apoptosis-inhibited chick embryos, we found that this apoptotic population is distinguishable by Foxp1 expression. When apoptosis was inhibited, the Foxp1+ MNs survived and showed characteristics of lateral motor column (LMC) neurons, which are of a limb-innervating subtype, suggesting that cervical Foxp1+ MNs are the rostral continuation of the LMC. Knockdown and misexpression of Foxp1 did not affect apoptosis progression, but revealed the role of Foxp1 in conferring LMC identity on the cervical MNs. Furthermore, ectopic expression of Hox genes that are normally expressed in the brachial region prevented apoptosis, and directed Foxp1+ MNs to LMC neurons at the cervical level. These results indicate that apoptosis in the cervical spinal cord plays a role in sculpting Foxp1+ MNs committed to LMC neurons, depending on the Hox expression pattern.
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Affiliation(s)
- Katsuki Mukaigasa
- Department of Neuroanatomy and Embryology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Chie Sakuma
- Department of Neuroanatomy and Embryology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Tomoaki Okada
- Department of Neuroanatomy and Embryology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Shunsaku Homma
- Department of Neuroanatomy and Embryology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Takako Shimada
- Department of Neuroanatomy and Embryology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Keiji Nishiyama
- Department of Neuroanatomy and Embryology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Noboru Sato
- Division of Gross Anatomy and Morphogenesis, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan
| | - Hiroyuki Yaginuma
- Department of Neuroanatomy and Embryology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
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Tung YT, Lu YL, Peng KC, Yen YP, Chang M, Li J, Jung H, Thams S, Huang YP, Hung JH, Chen JA. Mir-17∼92 Governs Motor Neuron Subtype Survival by Mediating Nuclear PTEN. Cell Rep 2016; 11:1305-18. [PMID: 26004179 DOI: 10.1016/j.celrep.2015.04.050] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 03/17/2015] [Accepted: 04/22/2015] [Indexed: 01/07/2023] Open
Abstract
Motor neurons (MNs) are unique because they project their axons outside of the CNS to innervate the peripheral muscles. Limb-innervating lateral motor column MNs (LMC-MNs) travel substantially to innervate distal limb mesenchyme. How LMC-MNs fine-tune the balance between survival and apoptosis while wiring the sensorimotor circuit en route remains unclear. Here, we show that the mir-17∼92 cluster is enriched in embryonic stem cell (ESC)-derived LMC-MNs and that conditional mir-17∼92 deletion in MNs results in the death of LMC-MNs in vitro and in vivo. mir-17∼92 overexpression rescues MNs from apoptosis, which occurs spontaneously during embryonic development. PTEN is a primary target of mir-17∼92 responsible for LMC-MN degeneration. Additionally, mir-17∼92 directly targets components of E3 ubiquitin ligases, affecting PTEN subcellular localization through monoubiquitination. This miRNA-mediated regulation modulates both target expression and target subcellular localization, providing LMC-MNs with an intricate defensive mechanism that controls their survival.
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Stifani N. Motor neurons and the generation of spinal motor neuron diversity. Front Cell Neurosci 2014; 8:293. [PMID: 25346659 PMCID: PMC4191298 DOI: 10.3389/fncel.2014.00293] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 09/02/2014] [Indexed: 11/13/2022] Open
Abstract
Motor neurons (MNs) are neuronal cells located in the central nervous system (CNS) controlling a variety of downstream targets. This function infers the existence of MN subtypes matching the identity of the targets they innervate. To illustrate the mechanism involved in the generation of cellular diversity and the acquisition of specific identity, this review will focus on spinal MNs (SpMNs) that have been the core of significant work and discoveries during the last decades. SpMNs are responsible for the contraction of effector muscles in the periphery. Humans possess more than 500 different skeletal muscles capable to work in a precise time and space coordination to generate complex movements such as walking or grasping. To ensure such refined coordination, SpMNs must retain the identity of the muscle they innervate. Within the last two decades, scientists around the world have produced considerable efforts to elucidate several critical steps of SpMNs differentiation. During development, SpMNs emerge from dividing progenitor cells located in the medial portion of the ventral neural tube. MN identities are established by patterning cues working in cooperation with intrinsic sets of transcription factors. As the embryo develop, MNs further differentiate in a stepwise manner to form compact anatomical groups termed pools connecting to a unique muscle target. MN pools are not homogeneous and comprise subtypes according to the muscle fibers they innervate. This article aims to provide a global view of MN classification as well as an up-to-date review of the molecular mechanisms involved in the generation of SpMN diversity. Remaining conundrums will be discussed since a complete understanding of those mechanisms constitutes the foundation required for the elaboration of prospective MN regeneration therapies.
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Affiliation(s)
- Nicolas Stifani
- Medical Neuroscience, Dalhousie University Halifax, NS, Canada
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5
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Kobayashi N, Homma S, Okada T, Masuda T, Sato N, Nishiyama K, Sakuma C, Shimada T, Yaginuma H. Elucidation of target muscle and detailed development of dorsal motor neurons in chick embryo spinal cord. J Comp Neurol 2014; 521:2987-3002. [PMID: 23504940 DOI: 10.1002/cne.23326] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 02/15/2013] [Accepted: 02/26/2013] [Indexed: 11/05/2022]
Abstract
The avian cervical spinal cord includes motoneurons (MNs) that send their axons through the dorsal roots. They have been called dorsal motoneurons (dMNs) and assumed to correspond to MNs of the accessory nerve that innervate the cucullaris muscle (SAN-MNs). However, their target muscles have not been elucidated to date. The present study sought to determine the targets and the specific combination of transcription factors expressed by dMNs and SAN-MNs and to describe the detailed development of dMNs. Experiments with tracing techniques confirmed that axons of dMNs innervated the cucullaris muscle. Retrogradely labeled dMNs were distributed in the ventral horn of C3 and more caudal segments. In most cases, some dMNs were also observed in the C2 segment. It was also demonstrated that SAN-MNs existed in the ventral horn of the C1-2 segments and the adjacent caudal hindbrain. Both SAN-MNs and dMNs expressed Isl1 but did not express Isl2, MNR2, or Lhx3. Rather, these MNs expressed Phox2b, a marker for branchial motoneurons (brMNs), although the intensity of expression was weaker. Dorsal MNs and SAN-MNs were derived from the Nkx2.2-positive precursor domain and migrated dorsally. Dorsal MNs remain in the ventral domain of the neural tube, unlike brMNs in the brainstem. These results indicate that dMNs and SAN-MNs belong to a common MN population innervating the cucullaris muscle and also suggest that they are similar to brMNs of the brainstem, although there are differences in Phox2b expression and in the final location of each population. J. Comp. Neurol. 521: 2987-3002, 2013. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- Nobumi Kobayashi
- Department of Neuroanatomy and Embryology, School of Medicine, Fukushima Medical University, Fukushima, Japan
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6
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Masuda T, Sakuma C, Taniguchi M, Kanemoto A, Yoshizawa M, Satomi K, Tanaka H, Takeuchi K, Ueda S, Yaginuma H, Shiga T. Development of the dorsal ramus of the spinal nerve in the chick embryo: a close relationship between development and expression of guidance cues. Brain Res 2012; 1480:30-40. [PMID: 22981415 DOI: 10.1016/j.brainres.2012.08.055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 08/02/2012] [Accepted: 08/29/2012] [Indexed: 11/15/2022]
Abstract
The spinal nerve, which is composed of dorsal root ganglion (DRG) axons and spinal motor axons, divides into ventral and dorsal rami. Although the development of the ventral ramus has been examined in considerable detail, that of the dorsal ramus has not. Therefore, we first examined the spatial-temporal pattern of the dorsal ramus formation in the chick embryo, with special reference to the projection to the dermamyotome and its derivatives. Next, we focused on two guidance molecules, chick semaphorin 3A (SEMA3A) and fibroblast growth factor 8 (FGF8), because these are the best candidates as molecules for controlling the dorsal ramus formation. Using in situ hybridization and immunohistochemistry methods, we clearly showed a close relationship between the spatial-temporal expression of SEMA3A/FGF8 and the projection of dorsal ramus fibers to the dorsal muscles. We further examined the axonal response of motor and DRG neurons to SEMA3A and FGF8. We showed that motor axons responded to both SEMA3A-induced repulsion and FGF8-induced attraction. On the other hand, DRG axons responded to SEMA3A-induced repulsion but not to FGF8-induced attraction. These findings suggest that FGF8-induced attraction may guide early motor axons beneath the myotome and that SEMA3A-induced repulsion may prevent these early motor axons from entering the myotome. Our results also imply that the loss of SEMA3A expression in the dorsal muscles may lead to the gross projection of the dorsal ramus fibers into the dorsal muscles. Together, SEMA3A and FGF8 may contribute to the proper formation of the dorsal ramus.
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Affiliation(s)
- Tomoyuki Masuda
- Department of Histology and Neurobiology, Dokkyo Medical University School of Medicine, Tochigi 321-0293, Japan.
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7
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Taylor AR, Gifondorwa DJ, Robinson MB, Strupe JL, Prevette D, Johnson JE, Hempstead BL, Oppenheim RW, Milligan CE. Motoneuron programmed cell death in response to proBDNF. Dev Neurobiol 2012; 72:699-712. [PMID: 21834083 PMCID: PMC3233653 DOI: 10.1002/dneu.20964] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Motoneurons (MN) as well as most neuronal populations undergo a temporally and spatially specific period of programmed cell death (PCD). Several factors have been considered to regulate the survival of MNs during this period, including availability of muscle-derived trophic support and activity. The possibility that target-derived factors may also negatively regulate MN survival has been considered, but not pursued. Neurotrophin precursors, through their interaction with p75(NTR) and sortilin receptors have been shown to induce cell death during development and following injury in the CNS. In this study, we find that muscle cells produce and secrete proBDNF. ProBDNF through its interaction with p75(NTR) and sortilin, promotes a caspase-dependent death of MNs in culture. We also provide data to suggest that proBDNF regulates MN PCD during development in vivo.
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Affiliation(s)
- AR Taylor
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine Winston-Salem, NC
| | - DJ Gifondorwa
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine Winston-Salem, NC
| | - MB Robinson
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine Winston-Salem, NC
| | - JL Strupe
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine Winston-Salem, NC
| | - D Prevette
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine Winston-Salem, NC
| | - JE Johnson
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine Winston-Salem, NC
| | - BL Hempstead
- Department of Medicine Cornell University Medical Center, NY
| | - RW Oppenheim
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine Winston-Salem, NC
- Interdisciplinary Neuroscience Program, Wake Forest University School of Medicine Winston-Salem, NC
- ALS Center, Wake Forest University School of Medicine Winston-Salem, NC
| | - CE Milligan
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine Winston-Salem, NC
- Interdisciplinary Neuroscience Program, Wake Forest University School of Medicine Winston-Salem, NC
- ALS Center, Wake Forest University School of Medicine Winston-Salem, NC
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8
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Lin YC, Marra KG. Injectable systems and implantable conduits for peripheral nerve repair. Biomed Mater 2012; 7:024102. [DOI: 10.1088/1748-6041/7/2/024102] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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9
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Wang M, Mominoki K, Kinutani M, Wang Z, Kobayashi N, Shimokawa T, Nabeka H, Fujiwara T, Matsuda S. Developmental delay in islet-1-positive motor neurons in chick spina bifida. J Vet Med Sci 2010; 73:447-52. [PMID: 21127393 DOI: 10.1292/jvms.10-0385] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spina bifida aperta (SBA) is a congenital malformation of the spinal cord with complications such as spinal ataxia and bowel and bladder dysfunction. We have developed a chick model with surgery-induced SBA that shows spinal ataxia after hatching. In the present study, motor neurons in the early stages in chicks with and without SBA were observed by immunohistochemical staining with a monoclonal antibody against Islet-1, a motor neuron marker. Delay in migration and maturation of motor neurons was observed in SBA. Although the final numbers of Islet-1-positive neurons in these two groups were not different, a defect in the production and elimination of excess motor neurons in the early developmental stages in the SBA group may be involved in the pathological mechanism of the motor complications of this disease.
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Affiliation(s)
- Min Wang
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Ehime, Japan
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Sisková Z, Page A, O'Connor V, Perry VH. Degenerating synaptic boutons in prion disease: microglia activation without synaptic stripping. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:1610-21. [PMID: 19779137 DOI: 10.2353/ajpath.2009.090372] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A growing body of evidence suggests that the loss of synapses is an early and major component of a number of neurodegenerative diseases. Murine prion disease offers a tractable preparation in which to study synaptic loss in a chronic neurodegenerative disease and to explore the underlying mechanisms. We have previously shown that synaptic loss in the hippocampus underpins the first behavioral changes and that there is a selective loss of presynaptic elements. The microglia have an activated morphology at this stage but they have an anti-inflammatory phenotype. We reasoned that the microglia might be involved in synaptic stripping, removing synapses undergoing a degenerative process, and that this gives rise to the anti-inflammatory phenotype. Analysis of synaptic density revealed a progressive loss from 12 weeks post disease initiation. The loss of synapses was not associated with microglia processes; instead, we found that the postsynaptic density of the dendritic spine was progressively wrapped around the degenerating presynaptic element with loss of subcellular components. Three-dimensional reconstructions of these structures from Dual Beam electron microscopy support the conclusion that the synaptic loss in prion disease is a neuron autonomous event facilitated without direct involvement of glial cells. Previous studies described synapse engulfment by developing and injured neurons, and we suggest that this mechanism may contribute to developmental and pathological changes in synapse numbers.
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Affiliation(s)
- Zuzana Sisková
- CNS Inflammation Group, Basset Crescent East, School of Biological Sciences, University of Southampton, Southampton SO16 7PX, UK.
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11
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Beck M, Karch C, Wiese S, Sendtner M. Motoneuron cell death and neurotrophic factors: Basic models for development of new therapeutic strategies in ALS. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/146608201300079454] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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12
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Moret F, Renaudot C, Bozon M, Castellani V. Semaphorin and neuropilin co-expression in motoneurons sets axon sensitivity to environmental semaphorin sources during motor axon pathfinding. Development 2008; 134:4491-501. [PMID: 18039974 DOI: 10.1242/dev.011452] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Class III semaphorins (SemaIIIs) are intercellular cues secreted by surrounding tissues to guide migrating cells and axons in the developing organism. This chemotropic activity is crucial for the formation of nerves and vasculature. Intriguingly, SemaIIIs are also synthesized by neurons during axon pathfinding, but their function as intrinsic cues remains unknown. We have explored the role of Sema3A expression in motoneurons during spinal nerve development. Loss- and gain-of-function in the neural tube of the chick embryo were undertaken to target Sema3A expression in motoneurons while preserving Sema3A sources localized in peripheral tissues, known to provide important repulsive information for delineating the routes of motor axons towards their ventral or dorsal targets. Strikingly, Sema3A overexpression induced defasciculation and exuberant growth of motor axon projections into these normally non-permissive territories. Moreover, knockdown studies showed that motoneuronal Sema3A is required for correct spinal nerve compaction and dorsal motor axon extension. Further analysis of Sema3A gain- and loss-of-function in ex vivo models revealed that Sema3A in motoneurons sets the level of sensitivity of their growth cones to exogenous Sema3A exposure. This regulation is associated with post-transcriptional and local control of the availability of the Sema3A receptor neuropilin 1 at the growth cone surface. Thus, by modulating the strength of Sema3A-mediated environmental repulsive constraints, Sema3A in motoneurons enables axons to extend more or less far away from these repulsive sources. Such interplay between intrinsic and extrinsic Sema3A may represent a fundamental mechanism in the accurate specification of axon pathways.
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Mashayekhi F. Neural cell death is induced by neutralizing antibody to nerve growth factor: an in vivo study. Brain Dev 2008; 30:112-7. [PMID: 17706905 DOI: 10.1016/j.braindev.2007.07.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2007] [Revised: 06/12/2007] [Accepted: 07/03/2007] [Indexed: 11/20/2022]
Abstract
The central nervous system (CNS) of vertebrates originates from neuroepithelial cells located within the embryonic neural tube. Coincidental with the processes of proliferation, migration and differentiation in the developing CNS, cell death is also a major phenomenon during normal development. The investigation of neural cell death in development has focused on the role of target-derived survival factors such as nerve growth factor (NGF). In this study, the effects of anti-NGF antibody on neural cell death in the cerebral cortex have been investigated. Injection of anti-NGF antibody into the cisterna magnum of mouse pups increased the number of neural cell deaths and resulted in thinning of the cerebral cortex compared with a control group. It is concluded that endogenous NGF is essential for cortical cell survival in the cerebral cortex of the newborn mouse. Moreover, this method may be applied to the other factors and different CNS regions, allowing identification of molecules and signals involved in neural cell survival.
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Affiliation(s)
- Farhad Mashayekhi
- Department of Biology, Faculty of Sciences, The University of Guilan, Rasht, Iran.
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14
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Bowen S, Ateh DD, Deinhardt K, Bird MM, Price KM, Baker CS, Robson JC, Swash M, Shamsuddin W, Kawar S, El-Tawil T, Roos J, Hoyle A, Nickols CD, Knowles CH, Pullen AH, Luthert PJ, Weller RO, Hafezparast M, Franklin RJM, Revesz T, King RHM, Berninghausen O, Fisher EMC, Schiavo G, Martin JE. The phagocytic capacity of neurones. Eur J Neurosci 2007; 25:2947-55. [PMID: 17561810 DOI: 10.1111/j.1460-9568.2007.05554.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Phagocytosis is defined as the ingestion of particulates over 0.5 microm in diameter and is associated with cells of the immune system such as macrophages or monocytes. Neurones are not generally recognized to be phagocytic. Using light, confocal, time-lapse and electron microscopy, we carried out a wide range of in-vitro and in-vivo experiments to examine the phagocytic capacity of different neuronal cell types. We demonstrated phagocytosis of material by neurones, including cell debris and synthetic particles up to 2.8 microm in diameter. We showed phagocytosis in different neuronal types, and demonstrated that debris can be transported from neurite extremities to cell bodies and persist within neurones. Flow cytometry analysis demonstrated the lack of certain complement receptors on neurones but the presence of others, including integrin receptors known to mediate macrophage phagocytosis, indicating that a restricted set of phagocytosis receptors may mediate this process. Neuronal phagocytosis occurs in vitro and in vivo, and we propose that this is a more widespread and significant process than previously recognized. Neuronal phagocytosis may explain certain inclusions in neurones during disease, cell-to-cell spread of disease, neuronal death during disease progression and provide a potential mechanism for therapeutic intervention through the delivery of particulate drug carriers.
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Affiliation(s)
- Samantha Bowen
- Neuroscience Centre and Pathology Group, Queen Mary's School of Medicine and Dentistry, Institute of Pathology, Royal London Hospital, London, UK
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15
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16
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Sato N, Sakuma C, Sato Y, Gould TW, Oppenheim RW, Yaginuma H. Distinct susceptibility of developing neurons to death following Bax overexpression in the chicken embryo. Cell Death Differ 2006; 13:435-45. [PMID: 16151456 DOI: 10.1038/sj.cdd.4401760] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Bax is a proapoptotic protein that is required for programmed cell death (PCD) of many neuronal populations. Here we show that, during an early period of retinal PCD and in naturally occurring sensory and motor neuron (MN) death in the spinal cord, Bax delivery results in enhanced death of these neural populations. In contrast, Bax overexpression fails to enhance an early phase of MN death that occurs in the cervical spinal cord, although overexpressed Bax appears to be activated in dying MNs. Bax overexpression does not also affect the survival of immature neurons prior to the PCD period. Taken together, these data provide the first in vivo evidence suggesting that Bax appears to act selectively as an executioner only in neurons undergoing PCD. Furthermore, although Bax appears to mediate the execution pathway for PCD, the effect of Bax overexpression on susceptibility to death differs between different neuronal populations.
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Affiliation(s)
- N Sato
- Department of Neuronatomy & Embryology, Fukushima Medical University School of Medicine, 1-Hikarigaoka, Fukushima 960-1295, Japan.
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17
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Banks GB, Chamberlain JS. Relevance of motoneuron specification and programmed cell death in embryos to therapy of ALS. ACTA ACUST UNITED AC 2006; 75:294-304. [PMID: 16425251 DOI: 10.1002/bdrc.20051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The molecular cues that generate spinal motoneurons in early embryonic development are well defined. Motoneurons are generated in excess and consequently undergo a natural period of programmed cell death. Although it is not known exactly how motoneurons compete for survival in embryonic development, it is hypothesized that they rely on the ability to access limited amounts of trophic factors from peripheral tissues, a process that is tightly regulated by skeletal muscle activity. Attempts to elucidate the molecular mechanisms that underlie motoneuron generation and programmed cell death in embryos have led to various effective strategies for treating injury and disease in animal models. Such studies provide great hope for the amelioration of human amyotrophic lateral sclerosis (ALS), a devastating progressive motoneuron degenerative disease. Here we review the clinical relevance of studying motoneuron specification and death during embryonic development.
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Affiliation(s)
- Glen B Banks
- Department of Neurology, University of Washington, Seattle, Washington 98195, USA.
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18
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Yamasoba T, Kondo K. Supporting cell proliferation after hair cell injury in mature guinea pig cochlea in vivo. Cell Tissue Res 2006; 325:23-31. [PMID: 16525832 DOI: 10.1007/s00441-006-0157-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Accepted: 01/04/2006] [Indexed: 10/24/2022]
Abstract
In cold-blooded animals, lost sensory hair cells can be replaced via a process of regenerative cell proliferation of epithelial supporting cells. In contrast, in mammalian cochlea, receptor (hair) cells are believed to be produced only during embryogenesis; after maturity, sensory or supporting cell proliferation or regeneration are thought to occur neither under normal conditions nor after trauma. Using bromodeoxyuridine (BrdU) as a proliferation marker, we have assessed cell proliferation activity in the mature organ of Corti in the cochlea of young guinea pigs following severe damage to the outer hair cells induced by kanamycin sulfate and ethacrynic acid. Although limited, we have found BrdU-labeled nuclei in the regions of Deiters cells when BrdU is given for 3 days or longer. When BrdU is given for 10 days, at least one labeled nucleus can be observed in the organ of Corti in approximately half of the ears; proliferating cells typically appear as paired daughters, with one nucleus being displaced away from the basement membrane to the position expected of the hair cells. Double-staining with antibodies to cytokeratin, vimentin, and p27 have shown that the BrdU-labeled nuclei are located in cells phenotypically similar to Deiters cells. Most of the uptake of BrdU occurs 3-5 days following ototoxic insult, and the number of BrdU-labeled cells does not decrease until 30 days following insult. These findings indicate that Deiters cells in the mature mammalian cochlea maintain a limited competence to re-enter the cell cycle and proliferate after hair cell injury, and that they can survive at least for 1 month.
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Affiliation(s)
- Tatsuya Yamasoba
- Department of Otolaryngology and Head and Neck Surgery, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8655, Japan.
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Duenker N. Transforming growth factor-beta (TGF-beta) and programmed cell death in the vertebrate retina. ACTA ACUST UNITED AC 2006; 245:17-43. [PMID: 16125544 DOI: 10.1016/s0074-7696(05)45002-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Programmed cell death (PCD) is a precisely regulated phenomenon essential for the homeostasis of multicellular organisms. Developmental systems, particularly the nervous system, have provided key observations supporting the physiological role of PCD. We have recently shown that transforming growth factor-beta (TGF-beta) plays an important role in mediating ontogenetic PCD in the nervous system. As part of the central nervous system the developing retina serves as an ideal model system for investigating apoptotic processes during neurogenesis in vivo as it is easily accessible experimentally and less complex due to its limited number of different neurons. This review summarizes data indicating a pivotal role of TGF-beta in mediating PCD in the vertebrate retina. The following topics are discussed: expression of TGF-beta isoforms and receptors in the vertebrate retina, the TGF-beta signaling pathway, functions and molecular mechanisms of PCD in the nervous system, TGF-beta-mediated retinal apoptosis in vitro and in vivo, and interactions of TGF-beta with other pro- and anti-apoptotic factors.
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Affiliation(s)
- Nicole Duenker
- Institute for Anatomy, Department of Neuroanatomy, University of Duisburg-Essen, 45122 Essen, Germany
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Przedborski S. Programmed cell death in amyotrophic lateral sclerosis: a mechanism of pathogenic and therapeutic importance. Neurologist 2004; 10:1-7. [PMID: 14720310 DOI: 10.1097/01.nrl.0000106920.84668.37] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Amyotrophic lateral sclerosis (ALS) is a fatal paralytic disease of adulthood. Mounting evidence indicates that molecular components of the programmed cell death (PCD) machinery are implicated in the demise of motor neurons in this illness. PCD, rather than being passive, is an active mechanism of cell death tightly regulated by multiple molecular pathways. REVIEW SUMMARY Thus far, little is known about the etiology and the pathogenesis of ALS. However, several studies support the view that PCD is instrumental in ALS neurodegenerative process. Data from postmortem ALS specimens and from experimental models of ALS show that some dying motor neurons exhibit features reminiscent of apoptosis, a prominent morphologic form of PCD. In addition, many key molecular components of the PCD machinery are activated in ALS spinal cords. Supporting the significance of these alterations, genetic and pharmacological interventions aimed at mitigating these changes prolong survival and attenuate neurodegeneration in a mouse model of ALS. CONCLUSIONS The morphologic evidence of PCD in ALS remains an equivocal. However, the molecular evidence of PCD involvement in ALS is compelling. Moreover, preclinical studies in mice demonstrate the beneficial effects of targeting PCD on ALS-like neurodegeneration. The neurologist needs to be familiar with the concept of PCD and the potential significance of targeting PCD as neuroprotective strategies for ALS.
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Affiliation(s)
- Serge Przedborski
- Department of Neurology, Center of Neurobiology and Behavior, Columbia University, New York, NY, USA.
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22
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Wiese S, Beck M, Karch C, Sendtner M. Signalling mechanisms for survival of lesioned motoneurons. ACTA NEUROCHIRURGICA. SUPPLEMENT 2004; 89:21-35. [PMID: 15335098 DOI: 10.1007/978-3-7091-0603-7_4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Mechanisms controlling neuronal survival play an important role both during development and after birth, in particular when the nervous system is lesioned. Isolated embryonic motoneurons and other types of primary neurons have been a useful tool for studying basic mechanisms underlying neuronal cell death during development and under pathophysiological conditions after neurotrauma. These studies have led to the identification of neurotrophic factors which under physiological conditions regulate survival and functional properties, and after neurotrauma promote regeneration and plasticity. Functional analysis of these molecules, in particular by generation of gene knockout mice, has led to a more detailed understanding of complex requirements of individual types of neurons for their survival and also paved the way for a better understanding of the signalling pathways in lesioned neurons which decide on cell death or survival after axotomy and other pathophysiological conditions. These findings could ultimately lead to a rational basis for therapeutic approaches aiming at improving neuronal survival and regeneration after neurotrauma.
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Affiliation(s)
- S Wiese
- Institute for Clinical Neurobiology, Würzburg, Germany
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23
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Homma S, Yaginuma H, Vinsant S, Seino M, Kawata M, Gould T, Shimada T, Kobayashi N, Oppenheim RW. Differential expression of the GDNF family receptors RET and GFRalpha1, 2, and 4 in subsets of motoneurons: a relationship between motoneuron birthdate and receptor expression. J Comp Neurol 2003; 456:245-59. [PMID: 12528189 DOI: 10.1002/cne.10529] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Previous studies have demonstrated the expression of specific members of the glial cell line-derived neurotrophic factor (GDNF) receptor family alpha (GFRalpha) in subsets of motoneurons (MNs) in the developing mouse spinal cord. We examined the expression pattern of GFRalpha and RET in the avian lumbar spinal cord during the period of programmed cell death (PCD) of MNs by using double labeling in situ hybridization and immunohistochemistry. In the lateral motor column (LMC) of the lumbar spinal cord, a laminar organization of GFRalpha expression was observed: GFRalpha1-positive MNs were located in the medial LMC; GFRalpha1-, 2-, and 4-positive MNs were situated in the lateral LMC; and GFRalpha4-positive MNs were located in the intermediate LMC. The species of GFRalpha receptor that was expressed in MNs was found to be related to their birthdates. The expression of subpopulation-specific transcriptional factors was also used to define MNs that express a specific pattern of GFRalpha. This analysis suggests that motor pools as defined by these transcriptional factors have unique expression patterns of GFRalpha receptor. Early limb bud ablation did not affect the expression of GFRalpha in the spinal cord, indicating that regulation of receptor expression is independent of target-derived signals. Finally, GDNF mRNA expression was found in the limb during the PCD period of MNs. In conclusion, these results indicate that time of withdrawal from the mitotic cycle may specify the expression pattern of GFRalpha in subsets of MNs and that GDNF may function as a target-derived neurotrophic factor for specific subpopulations of MNs.
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Affiliation(s)
- Shunsaku Homma
- Department of Anatomy, School of Medicine, Fukushima Medical University, Japan.
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24
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Przedborski S, Vila M, Jackson-Lewis V. Series Introduction: Neurodegeneration: What is it and where are we? J Clin Invest 2003. [DOI: 10.1172/jci200317522] [Citation(s) in RCA: 248] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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26
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Sato N, Sakuma C, Kato H, Milligan CE, Oppenheim RW, Yaginuma H. Bcl-2 rescues motoneurons from early cell death in the cervical spinal cord of the chicken embryo. JOURNAL OF NEUROBIOLOGY 2002; 53:381-90. [PMID: 12382265 DOI: 10.1002/neu.10108] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Motoneurons (MNs) in the cervical spinal cord of the chicken embryo undergo programmed cell death (PCD) between embryonic day (E) 4 and E5. The intracellular molecules regulating this early phase of PCD remain unknown. Here we show that introduction of Bcl-2 by a replication-competent avian retroviral vector prevented MN degeneration at E4.5, whereas the expression of the green fluorescent protein (GFP) was ineffective. Bcl-2 expression did not affect the number of Islet-1/2-positive MNs at the onset of cell death (E4). However, when examined at the end of the cell death period (E5.5), the number of Islet-1/2-positive MNs was clearly increased in Bcl-2-transfected embryos compared with control and GFP-transfected embryos. Activation of caspase-3, which is normally observed in this early MN death, was also prevented by Bcl-2. Thus, MNs in the cervical spinal cord appear to use intracellular pathway(s) for early PCD that is responsive to Bcl-2.
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Affiliation(s)
- Noboru Sato
- Department of Anatomy, Fukushima Medical University School of Medicine, Fukushima 960-1295 Japan
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27
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Chan WY, Lorke DE, Tiu SC, Yew DT. Proliferation and apoptosis in the developing human neocortex. THE ANATOMICAL RECORD 2002; 267:261-76. [PMID: 12124904 DOI: 10.1002/ar.10100] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The cell kinetics of the developing central nervous system (CNS) is determined by both proliferation and apoptosis. In the human neocortex at week 6 of gestation, proliferation is confined to the ventricular zone, where mitotic figures and nuclear immunoreactivity for proliferating cell nuclear antigen (PCNA) are detectable. Cell division is symmetric, with both daughter cells reentering mitosis. At week 7, the subventricular zone, a secondary proliferative zone, appears. It mainly gives rise to local circuit neurons and glial cells. Around week 12, the ventricular and subventricular zones are thickest, and the nuclear PCNA label is strongest, indicating that proliferation peaks at this stage. Thereafter, asymmetric division becomes the predominant mode of proliferation, with one daughter cell reentering mitosis and the other one migrating out. Towards late gestation, the ventricular and subventricular zones almost completely disappear and proliferation shifts towards the intermediate and subplate zones, where mainly glial cells are generated. A remnant of the subventricular zone with proliferative activity persists into adulthood. In general, proliferation follows a latero-medial gradient in the neocortex lasting longer in its lateral parts. Apoptotic nuclei have been detected around week 5, occurring in low numbers in the ventricular zone at this stage. Apoptotic cell death increases around midgestation and then spreads throughout all cortical layers, with most dying cells located in the ventricular and subventricular zones. This spatial distribution of apoptosis extends into late gestation. During the early postnatal period, most apoptotic cells are still located in the subcortical layers. During early embryonic development, proliferation and apoptosis are closely related, and are probably regulated by common regulators. In the late fetal and early postnatal periods, when proliferation has considerably declined in all cortical layers, apoptosis may occur in neurons whose sprouting axons do not find their targets.
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Affiliation(s)
- Wood Yee Chan
- Department of Anatomy, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
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28
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Falkowski A, Hammond R, Han V, Richardson B. Apoptosis in the preterm and near term ovine fetal brain and the effect of intermittent umbilical cord occlusion. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2002; 136:165-73. [PMID: 12101033 DOI: 10.1016/s0165-3806(02)00361-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Programmed cell death or apoptosis plays a central role during the development of the brain, but can also be activated by hypoxic/ischemic insult. The purpose of the present study was to determine the regional distribution of apoptotic cells in the preterm and near term ovine fetal brain and thus in relation to the maturation of neurobehavioural activity, and the effect of intermittent umbilical cord occlusion (UCO), which might then contribute to adverse neurodevelopment. Fetal sheep (control and experimental groups at 0.75 and 0.90 of gestation) were studied over 4 days with UCOs performed in the experimental group animals by complete inflation of an occluder cuff for 90 s every 30 min for 3 to 5 h each day. Animals were then euthanized and the fetal brain perfusion-fixed and prepared for subsequent histology and apoptosis staining using the TUNEL assay method. The number of TUNEL positive cells for both the preterm and near term control group animals was low but with a significant regional hierarchy whereby values were higher in the cerebellar peduncle and cortex and lower in the cortical grey and white matter, hippocampus, and pons. While the apoptotic indices (expressed as TUNEL positive cells/1000 cells or high powered field) for most brain regions were not significantly changed between the preterm and near term control group animals, that for the hippocampus and pons were increased approximately 5- and 4-fold, respectively, (both P<0.05), in the near term animals. Intermittent UCO with severe but limited hypoxemia and no cumulative acidosis to ensure longer term survival, had no significant effect on apoptotic indices in the brains of either the preterm or near term animals, although hippocampal values for both occlusion groups were increased approximately 2-3-fold. Levels of apoptosis noted for the ovine fetal brain at 0.75 to 0.90 of gestation are thus low and likely approaching the basal levels of later life, but there are regional differences and changes over this period although little change in response to intermittent cord occlusion as studied, with implications for behavioural state activity and antenatal hypoxic insults in the brain's development.
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Affiliation(s)
- Anna Falkowski
- CIHR Group in Fetal and Neonatal Health and Development, Department of Obstetrics and Gynaecology, The Lawson Heath Research Institute, University of Western Ontario, London, Canada
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29
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Bennet MR, Gibson WG, Lemon G. Neuronal cell death, nerve growth factor and neurotrophic models: 50 years on. Auton Neurosci 2002; 95:1-23. [PMID: 11871773 DOI: 10.1016/s1566-0702(01)00358-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Viktor Hamburger has just died at the age of 100. It is 50 years since he and Rita Levi-Montalcini laid the foundations for the study of naturally occurring cell death and of neurotrophic factors in the nervous system. In a period of less than 10 years, from 1949 to 1958, Hamburger and Levi-Montalcini made the following seminal discoveries: that neuron cell death occurs in dorsal root ganglia, sympathetic ganglia and the cervical column of motoneurons; that the predictions arising from this observation, namely that survival is dependent on the supply of a trophic factor, could be substantiated by studying the effects of a sarcoma on the proliferation of ganglionic processes both in vivo and in vitro; and that the proliferation of these processes could be used as an assay system to isolate the factor. This work provides a short review mostly of the early history of this subject in the context of the Hamburger/Levi-Montalcini paradigm. This acts as an introduction to a consideration of models that have been proposed to account for how the different sources of growth factors provide for the survival of neurons during development. It is suggested that what has been called the 'social-control' model provides the most parsimonious quantitative description of the contribution of trophic factors to neuronal survival, a concept for which we are in debt to Viktor Hamburger and Rita Levi-Montalcini.
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Affiliation(s)
- M R Bennet
- Department of Physiology, Institute for Biomedical Research, University of Sydney, New South Wales, Australia.
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30
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Yaginuma H, Sato N, Homma S, Oppenheim RW. Roles of caspases in the programmed cell death of motoneurons in vivo. ARCHIVES OF HISTOLOGY AND CYTOLOGY 2001; 64:461-74. [PMID: 11838706 DOI: 10.1679/aohc.64.461] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cysteine proteases comprising the caspase family have been considered one of the major executioners of programmed cell death. However, detailed analyses of the programmed cell death of developing motoneurons in mice following the genetic deletion of two key caspases, casp-3 and casp-9, and in the chick embryo following treatment with caspase inhibitors, indicate that normal amounts of cell loss occur although the death process is delayed. Motoneurons undergoing programmed cell death without caspase activities exhibit a nonapoptotic morphology in which nuclear changes such as chromatin condensation are absent or reduced and which exhibit extensive cytoplasmic vacuolization such as is rarely observed in degenerating control neurons. These results suggest that caspases are involved in, but are not indispensable for, the developmental death of motoneurons, and that one function of caspases may be to facilitate the removal of cells that are destined to die. Possible alternative caspase-independent pathways for the programmed death of motoneurons are discussed.
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Affiliation(s)
- H Yaginuma
- Department of Anatomy, School of Medicine, Fukushima Medical University, Japan.
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31
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Nat R, Radu E, Regalia T, Popescu LM. Apoptosis in human embryo development: 3. Fas-induced apoptosis in brain primary cultures. J Cell Mol Med 2001; 5:417-28. [PMID: 12067476 PMCID: PMC6740267 DOI: 10.1111/j.1582-4934.2001.tb00177.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Fas (APO-1/CD95) is an important apoptotic mediator for both immune and nervous systems. In the present study, we have investigated the expression and function of Fas in human embryonic/fetal brain primary cultures from 12 human embryos and fetuses with gestational ages between 5 to 22 weeks. Anti-Fas fluorescent antibody was used for labeling of Fas positive cells and for quantitation of Fas expression in brain cultures. To demonstrate that Fas receptor is functional in human embryonic/fetal brain cells, anti-Human-Fas monoclonal antibody (0.5 microg/ml) was used to induce apoptosis in brain primary cultures. Apoptosis was investigated by flow-cytometry and fluorescent microscopy using TUNEL and annexin V labeling. Fas was found to be expressed in the embryonic/fetal human primary brain cultures, on neuronal and glial cells or their precursors, varying with gestational ages. Cross-linking of Fas induced apoptosis in brain cultures indicating that Fas receptor functions as a death receptor. We also showed that cell death triggered through Fas receptor was caspase dependent, hence it was blocked by a selective caspase-8 inhibitor (IETD-fmk). These results suggest that Fas is involved in neuronal apoptosis in the developing human brain.
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Affiliation(s)
- R Nat
- Division of Cellular and Molecular Medicine, Carol Davila University of Medicine and Pharmacy, 8 Eroilor Sanitari, Bucharest, Romania
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32
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Esdar C, Milasta S, Maelicke A, Herget T. Differentiation-associated apoptosis of neural stem cells is effected by Bcl-2 overexpression: impact on cell lineage determination. Eur J Cell Biol 2001; 80:539-53. [PMID: 11561905 DOI: 10.1078/0171-9335-00185] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Apoptosis is an integral part of neural development. To elucidate the importance of programmed cell death on cell lineage determination we utilized murine PCC7-Mzl cells, a model system for neural differentiation. Treatment of pluripotent PCC7-Mzl stem cells with 0.1 microM all-trans retinoic acid (RA) causes a cease of proliferation and an initiation of differentiation into neurons, glial cells and fibroblasts. Simultaneously, a fraction of the cell culture (ca. 25%) dies within 24 h by apoptosis. We transfected PCC7-Mzl cells with the human bcl-2 cDNA and generated PCC7-Mz-Bcl-2 cell lines expressing two- to tenfold higher levels of Bcl-2 than parental cells. Overexpression of Bcl-2 resulted in hypophosphorylation of the retinoblastoma (Rb) protein and consequently prolonged the doubling time of the culture from 18 h to 23 h. RA-induced apoptosis was drastically reduced to 3 to 15% depending on the level of Bcl-2 expression. RA-induced caspase activation, cytochrome c release from the mitochondria to the cytosol and DNA fragmentation was completely blocked. Furthermore, treating Bcl-2 cultures with ceramide (10 microM), a second messenger mediating the RA-initiated death signal in parental cells, no longer caused DNA laddering. Bcl-2 overexpression did not interfere with the potential of PCC7-Mz cells to develop into neurons, glial cells and fibroblasts. However, the relative distribution of cell types in the culture was shifted such that the fraction of neurons was reduced to half (from 60 to 30%) with a concomitant increase in the number of glial and fibroblastoid cells. Furthermore, Bcl-2-overexpressing neurons, but not neurons of parental or mock-transfected PCC7-Mzl cultures, were able to grow as single cells.
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Affiliation(s)
- C Esdar
- Axxima Pharmaceuticals AG, Martinsried/Germany
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33
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Yaginuma H, Shiraiwa N, Shimada T, Nishiyama K, Hong J, Wang S, Momoi T, Uchiyama Y, Oppenheim RW. Caspase activity is involved in, but is dispensable for, early motoneuron death in the chick embryo cervical spinal cord. Mol Cell Neurosci 2001; 18:168-82. [PMID: 11520178 DOI: 10.1006/mcne.2001.1009] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined the role of caspases in the early programmed cell death (PCD) of motoneurons (MNs) in the chick embryo cervical cord between embryonic day (E) 4 and E5. An increase in caspase-3-like activity in MNs was observed at E4.5. Treatment with an inhibitor of caspase-3-like activity, Ac-DEVD-CHO, for 12 h blocked this increase and revealed that caspase-3-like activity is mainly responsible for DNA fragmentation and the nuclear changes during PCD but not for degenerative changes in the cytoplasm. When a more broad-spectrum caspase inhibitor was used (bocaspartyl (OMe)-fluoromethyl ketone, BAF), the appearance of degenerative changes in the cytoplasm was delayed by at least 12 h. However, following treatment with either Ac-DEVD-CHO or BAF for 24 h, the number of surviving healthy MNs did not differ from controls, indicating a normal occurrence of PCD despite the inhibition of caspases. These results suggest that caspase cascades that occur upstream of and are independent of the activation of caspase-3-like activity are responsible for the degenerative changes in the cytoplasm of dying cervical MNs. These data also suggest that, although one function of caspases may be to facilitate the kinetics of PCD, caspases are nonetheless dispensable for at least some forms of normal neuronal PCD in vivo.
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Affiliation(s)
- H Yaginuma
- Department of Anatomy, Fukushima Medical University, Fukushima 960-1295, Japan.
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34
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Oppenheim RW, Flavell RA, Vinsant S, Prevette D, Kuan CY, Rakic P. Programmed cell death of developing mammalian neurons after genetic deletion of caspases. J Neurosci 2001; 21:4752-60. [PMID: 11425902 PMCID: PMC6762357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
An analysis of programmed cell death of several populations of developing postmitotic neurons after genetic deletion of two key members of the caspase family of pro-apoptotic proteases, caspase-3 and caspase-9, indicates that normal neuronal loss occurs. Although the amount of cell death is not altered, the death process may be delayed, and the cells appear to use a nonapoptotic pathway of degeneration. The neuronal populations examined include spinal interneurons and motor, sensory, and autonomic neurons. When examined at both the light and electron microscopic levels, the caspase-deficient neurons exhibit a nonapoptotic morphology in which nuclear changes such as chromatin condensation are absent or reduced; in addition, this morphology is characterized by extensive cytoplasmic vacuolization that is rarely observed in degenerating control neurons. There is also reduced terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling in dying caspase-deficient neurons. Despite the altered morphology and apparent temporal delay in cell death, the number of neurons that are ultimately lost is indistinguishable from that seen in control animals. In contrast to the striking perturbations in the morphology of the forebrain of caspase-deficient embryos, the spinal cord and brainstem appear normal. These results are consistent with the growing idea that the involvement of specific caspases and the occurrence of caspase-independent programmed cell death may be dependent on brain region, cell type, age, and species or may be the result of specific perturbations or pathology.
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Affiliation(s)
- R W Oppenheim
- Department of Neurobiology and Anatomy and the Neuroscience Program, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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35
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Pifl C, Zezula J, Spittler A, Kattinger A, Reither H, Caron MG, Hornykiewicz O. Antiproliferative action of dopamine and norepinephrine in neuroblastoma cells expressing the human dopamine transporter. FASEB J 2001; 15:1607-9. [PMID: 11427501 DOI: 10.1096/fj.00-0738fje] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- C Pifl
- Brain Research Institute, Pharmacological Institute and. Department of Surgery, University of Vienna, 1090 Vienna, Austria.
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36
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Lance-Jones C, Omelchenko N, Bailis A, Lynch S, Sharma K. Hoxd10 induction and regionalization in the developing lumbosacral spinal cord. Development 2001; 128:2255-68. [PMID: 11493545 DOI: 10.1242/dev.128.12.2255] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have used Hoxd10 expression as a primary marker of the lumbosacral region to examine the early programming of regional characteristics within the posterior spinal cord of the chick embryo. Hoxd10 is uniquely expressed at a high level in the lumbosacral cord, from the earliest stages of motor column formation through stages of motoneuron axon outgrowth. To define the time period when this gene pattern is determined, we assessed Hoxd10 expression after transposition of lumbosacral and thoracic segments at early neural tube stages. We present evidence that there is an early prepattern for Hoxd10 expression in the lumbosacral neural tube; a prepattern that is established at or before stages of neural tube closure. Cells within more posterior lumbosacral segments have a greater ability to develop high level Hoxd10 expression than the most anterior lumbosacral segments or thoracic segments. During subsequent neural tube stages, this prepattern is amplified and stabilized by environmental signals such that all lumbosacral segments acquire the ability to develop high levels of Hoxd10, independent of their axial environment. Results from experiments in which posterior neural segments and/or paraxial mesoderm segments were placed at different axial levels suggest that signals setting Hoxd10 expression form a decreasing posterior-to-anterior gradient. Our experiments do not, however, implicate adjacent paraxial mesoderm as the only source of graded signals. We suggest, instead, that signals from more posterior embryonic regions influence Hoxd10 expression after the early establishment of a regional prepattern. Concurrent analyses of patterns of LIM proteins and motor column organization after experimental surgeries suggest that the programming of these characteristics follows similar rules.
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Affiliation(s)
- C Lance-Jones
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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Nakatsuji Y, Miller RH. Selective cell-cycle arrest and induction of apoptosis in proliferating neural cells by ganglioside GM3. Exp Neurol 2001; 168:290-9. [PMID: 11259117 DOI: 10.1006/exnr.2000.7602] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Control of cell proliferation and cell survival is critical during development of the vertebrate central nervous system (CNS). Much of the cell death seen during early stages of CNS development occurs through apoptosis; however, the factors that induce this early apoptosis are not clearly understood. Gangliosides, sialylated glycosphingolipids, are expressed in the CNS and have been proposed to regulate cell growth and differentiation. Here we show that the simple ganglioside GM3 selectively inhibits the proliferation of and induces apoptosis of actively dividing astrocyte precursors and other neural progenitors. The inhibition of astrocyte precursor proliferation by GM3 appears to be mediated in part by the cyclin-dependent kinase (Cdk) inhibitor p27(Kip1). During neonatal development there is extensive cell proliferation and little apoptosis in the ventricular and subventricular zones of the CNS. This proliferation was dramatically inhibited and the degree of apoptosis dramatically increased following intraventricular administration of GM3. These data suggest that GM3, a simple ganglioside, may regulate cell proliferation and death in the CNS and as such may have potential for brain tumor therapy.
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Affiliation(s)
- Y Nakatsuji
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
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38
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Abstract
The important effect of cell death on projecting neurons during development is well established. However, this mainstream research might have diverted recognition of the cell death that occurs at earlier stages of neural development, affecting proliferating neural precursor cells and young neuroblasts. In this article, we briefly present observations supporting the occurrence of programmed cell death during early neural development in a regulated fashion that to some extent parallels the death of projecting neurons lacking neurotrophic support. These findings raise new questions, in particular the magnitude and the role of this early neural cell death.
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Affiliation(s)
- E J de la Rosa
- Dept of Cell and Developmental Biology, Centro de Investigaciones Biológicas, CSIC, Velázquez 144, E-28006, Madrid, Spain
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Herget T, Esdar C, Oehrlein SA, Heinrich M, Schütze S, Maelicke A, van Echten-Deckert G. Production of ceramides causes apoptosis during early neural differentiation in vitro. J Biol Chem 2000; 275:30344-54. [PMID: 10862608 DOI: 10.1074/jbc.m000714200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To investigate signal transduction pathways leading to apoptosis during the early phase of neurogenesis, we employed PCC7-Mz1 cells, which cease to proliferate and begin to differentiate into a stable pattern of neurons, astroglial cells, and fibroblasts upon incubation with retinoic acid (RA). As part of lineage determination, a sizable fraction of RA-treated cultures die by apoptosis. Applying natural long-chain C(16)-ceramides as well as membrane-permeable C(2)/C(6)-ceramide analogs caused apoptosis, whereas the biologically nonactive C(2)-dihydroceramide did not. Treating PCC7-Mz1 stem cells with a neutral sphingomyelinase or with the ceramidase inhibitor N-oleoylethanolamine elevated the endogenous ceramide levels and concomitantly induced apoptosis. Addition of RA caused an increase in ceramide levels within 3-5 h, which reached a maximum (up to 3.5-fold of control) between days 1 and 3 of differentiation. Differentiated PCC7-Mz1 cells did not respond with ceramide formation and apoptosis to RA treatment. The acidic sphingomyelinase contributed only weakly and the neutral Mg(2+)-dependent and Mg(2+)-independent sphingomyelinases not at all to the RA-mediated production of ceramides. However, ceramide increase was sensitive to the ceramide synthase inhibitor fumonisin B(1), suggesting a crucial role for the de novo synthesis pathway. Enzymatic assays revealed that ceramide synthase activity remained unaltered, whereas serine palmitoyltransferase (SPT), a key enzyme in ceramide synthesis, was activated approximately 2.5-fold by RA treatment. Activation of SPT seemed to be mediated via a post-translational mechanism because levels of the mRNAs coding for the two SPT subunits were unaffected. Expression of marker proteins shows that ceramide regulates apoptosis, rather than differentiation, during early neural differentiation.
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Affiliation(s)
- T Herget
- Laboratory of Molecular Neurobiology, University of Mainz, 55099 Mainz, Germany.
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Abstract
Programmed cell death (PCD) in the form of apoptosis is recognized as one of the central events in the development of the central nervous system. To study the time of onset, extent and distribution of PCD in the human telencephalon, embryos and fetuses from 4.5 to 27 gestational weeks (g.w.) were examined using the TUNEL (TdT-mediated dUTP-biotin nick-end labelling) in situ method. At 4.5 g.w. sparse TUNEL(+) nuclei were observed in the ventricular zone of the neural tube. With the formation of the cortical plate at 7-8 g.w. , TUNEL(+) nuclei were seen in all developmental layers of the cortical anlage, as well as in the subcortical regions such as the ganglionic eminence and the internal capsule. The proliferative zones (the ventricular zone, the subventricular zone and the ganglionic eminence) contained the majority of all apoptotic nuclei observed in each specimen. However, the apoptotic index was highest in the subplate zone and in layer I. Double-labelling experiments suggested that neuronal precursors were the main population of cells undergoing PCD in the first trimester of gestation, whereas glial cells probably start dying around midgestation. The onset of labelling of microglial cells and apoptotic nuclei were synchronous, indicating the involvement of microglia in PCD. In conclusion, two distinct types of PCD were observed during human telencephalic development: embryonic apoptosis, which was synchronous with proliferation and migration of neuronal cells and probably not related to establishment of neuronal circuitry, and fetal apoptosis, which coincided with differentiation and synaptogenesis, and therefore may be related to the development of axonal-target connectivity.
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Affiliation(s)
- S Rakic
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030-3401, USA
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41
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Abstract
To review the data on the origins, phenotype, and function of embryonic phagocytes that has accumulated over past decade. Most of the relevant articles were selected based on the PubMed database entries. In additional, the Interactive Fly database (http://sdb.bio. purdue.edu/fly/aimain/1aahome.htm), FlyBase (http://flybase.bio. indiana.edu:82/), and TBase (http://tbase.jax.org/) were used to search for relevant information and articles. Phagocytes in a vertebrate embryo develop in two sites (yolk sac and liver) and contribute to organogenesis in part through their ability to recognize and clear apoptotic cells. Yolk sac-derived phagocytes differ in differentiation pathway and marker gene expression from macrophages produced via classic hematopoietic progenitors in the liver. We argue that yolk sac-derived phagocytes constitute a separate cell lineage. This conclusion raises the question of whether primitive phagocytes persist into the adulthood.
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Affiliation(s)
- A M Lichanska
- Departments of Medical Genetics and Ophthalmology, Queen's University of Belfast, Belfast, United Kingdom
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Holzenberger M, Lapointe F, Ayer-LeLièvre C. Expression of insulin-like growth factor-I (IGF-I) and IGF-II in the avian brain: relationship of in situ hybridization patterns with IGF type 1 receptor expression. Int J Dev Neurosci 2000; 18:69-82. [PMID: 10708908 DOI: 10.1016/s0736-5748(99)00076-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Insulin-like growth factors (IGFs) are expressed in defined spatiotemporal patterns during the development of the mammalian central nervous system (CNS). Since IGF expression in avian species is less well documented, we studied here the expression of IGF-I and IGF-II during chicken CNS development, using in situ hybridization and reverse transcriptase-PCR, and compared the results with the expression of the IGF type 1 receptor (IGF-1R). IGF-II expression started early in embryonic life, shortly after the onset of IGF-1R expression. During organogenesis, IGF-II was strongly expressed in kidney, liver and gut primordia, in contrast with IGF-1R mRNA, which is highly enriched in proliferating neuroepithelia. During the second half of embryonic development, IGF-I and IGF-II had distinct expression patterns, suggesting specific roles for each ligand during brain maturation. IGF-II mRNA was found in numerous brainstem nuclei and in the optic tectum, whereas IGF-I mRNA was found predominantly in telencephalic regions. Both ligands were expressed in the cerebellum, but each by different cell layers. Some brain regions (olfactory bulb and olivo-cerebellar system) did not exhibit the postnatal downregulation typical of extrahepatic IGF-I expression, but continued to express IGF-I into adulthood. Purkinje cells expressed IGF-II in the embryo, but switched to IGF-I expression in the adult. The conservation of embryonic and postnatal IGF expression patterns in the CNS between avians and mammals suggests that the involvement of the IGF system in neurogenesis and differentiation, and possibly in neural plasticity and learning, may have arisen early during tetrapode/vertebrate evolution.
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Affiliation(s)
- M Holzenberger
- INSERM Unite 515, Hôpital Saint-Antoine, F-75571, Paris, France.
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Miller RH, Hayes JE, Dyer KL, Sussman CR. Mechanisms of oligodendrocyte commitment in the vertebrate CNS. Int J Dev Neurosci 1999; 17:753-63. [PMID: 10593611 DOI: 10.1016/s0736-5748(99)00068-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- R H Miller
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106, USA.
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Yamamoto Y, Henderson CE. Patterns of programmed cell death in populations of developing spinal motoneurons in chicken, mouse, and rat. Dev Biol 1999; 214:60-71. [PMID: 10491257 DOI: 10.1006/dbio.1999.9413] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During embryonic development, approximately one-half of the spinal motoneurons initially generated are lost during a wave of programmed cell death (PCD). Classical studies in this system laid the basis of much work on the role and control of neuronal cell death during development. However, we have little information concerning the timing of cell death in motoneuron pools at different rostrocaudal levels, especially in rodents. We developed a novel protocol for whole-mount TUNEL labeling that allows apoptotic nuclei to be visualized in whole-mount preparations of embryonic spinal cord; double labeling with antibodies to Islet 1/2 showed that nearly all TUNEL-positive cells were motoneurons. In chicken and mouse embryos, the density of TUNEL-positive nuclei was specifically increased following target ablation. The pattern of naturally occurring motoneuron PCD was studied in spinal cords from different species and ages: chick (E4.5-E9.0), mouse (E11.5-E15.5), and rat (E13.5-E16. 5). In all species, motoneuron PCD is first apparent at cervical levels and last at sacral levels. However, motoneuron PCD does not follow a strict rostrocaudal sequence. Following cervical motoneuron PCD, TUNEL profiles are first observed at lumbar levels in chick but at thoracic levels in rat. At a given rostrocaudal level, medial motoneurons tend to die before lateral populations, but here too there are exceptions. Motoneuron cell death is thus regulated in a highly stereotyped manner during development of vertebrate spinal cord. Our technique will provide a basis for the monitoring even localized changes in this pattern.
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Affiliation(s)
- Y Yamamoto
- INSERM U.382, Developmental Biology Institute of Marseille (IBDM), CNRS, INSERM, Université Méditerranée, AP Marseille, Campus de Luminy, Case 907, Marseille Cedex 09, 13288, France
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45
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46
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Wagner JP, Black IB, DiCicco-Bloom E. Stimulation of neonatal and adult brain neurogenesis by subcutaneous injection of basic fibroblast growth factor. J Neurosci 1999; 19:6006-16. [PMID: 10407038 PMCID: PMC6783097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/1998] [Revised: 04/13/1999] [Accepted: 04/28/1999] [Indexed: 02/13/2023] Open
Abstract
Mounting evidence indicates that extracellular factors exert proliferative effects on neurogenetic precursors in vivo. Recently we found that systemic levels of basic fibroblast growth factor (bFGF) regulate neurogenesis in the brain of newborn rats, with factors apparently crossing the blood-brain barrier (BBB) to stimulate mitosis. To determine whether peripheral bFGF affects proliferation during adulthood, we focused on regions in which neurogenesis persists into maturity, the hippocampus and the forebrain subventricular zone (SVZ). In postnatal day 1 (P1) rats, 8 hr after subcutaneous injection (5 ng/gm body weight), bFGF increased [(3)H]thymidine incorporation 70% in hippocampal and SVZ homogenates and elicited twofold increases in mitotic nuclei in the dentate gyrus and the dorsolateral SVZ, detected by bromodeoxyuridine immunohistochemistry. Because approximately 25% of proliferating hippocampal cells stimulated in vivo expressed neuronal traits in culture, bFGF-induced mitosis may reflect increased neurogenesis. bFGF effects were not restricted to the perinatal period; hippocampal DNA synthesis was stimulated by peripheral factor in older animals (P7-P21), indicating the persistence of bFGF-responsive cells and activity of peripheral bFGF into late development. To begin defining underlying mechanisms, pharmacokinetic studies were performed in P28 rats; bFGF transferred from plasma to CSF rapidly, levels rising in both compartments in parallel, indicating that peripheral factor crosses the BBB during maturity. Consequently, we tested bFGF in adults; peripheral bFGF increased the number of mitotic nuclei threefold in the SVZ and olfactory tract, regions exhibiting persistent neurogenesis. Our observations suggest that bFGF regulates ongoing neurogenesis via a unique, endocrine-like pathway, potentially coordinating neuron number and body growth, and potentially providing new approaches for treating damaged brain during development and adulthood.
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Affiliation(s)
- J P Wagner
- Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey/Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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47
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Hatton WJ, Von Bartheld CS. Analysis of cell death in the trochlear nucleus of the chick embryo: Calibration of the optical disector counting method reveals systematic bias. J Comp Neurol 1999. [DOI: 10.1002/(sici)1096-9861(19990628)409:2<169::aid-cne1>3.0.co;2-o] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Berggren K, McCaffery P, Dräger U, Forehand CJ. Differential distribution of retinoic acid synthesis in the chicken embryo as determined by immunolocalization of the retinoic acid synthetic enzyme, RALDH-2. Dev Biol 1999; 210:288-304. [PMID: 10357892 DOI: 10.1006/dbio.1999.9286] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Retinaldehyde dehydrogenase type 2 (RALDH-2) is a major retinoic acid generating enzyme in the early embryo. Here we report the immunolocalization of this enzyme (RALDH-2-IR) in stage 6-29 chicken embryos; we also show that tissues that exhibit strong RALDH-2-IR in the embryo contain RALDH-2 and synthesize retinoic acid. RALDH-2-IR indicates dynamic and discrete patterns of retinoic acid synthesis in the embryo, particularly within the somitic mesoderm, lateral mesoderm, kidney, heart, and spinal motor neurons. Prior to somitogenesis, RALDH-2-IR is present in the paraxial mesoderm with a rostral boundary at the level of the presumptive first somite; as the somites form, they exhibit strong RALDH-2-IR. Cervical presomitic mesoderm exhibits RALDH-2-IR but thoracic presomitic mesoderm does not. Neural crest cells do not express detectable levels of RALDH-2, but migrating crest cells are associated with RALDH-2 expressing mesoderm. The developing limb mesoderm expresses little RALDH-2-IR; however, RALDH-2-IR is strongly expressed in tissues adjacent to the limb. The most lateral, earliest-projecting motor neurons at all levels of the spinal cord exhibit RALDH-2-IR. Subsequently, many additional motor neurons in the brachial and lumbar cord regions express RALDH-2-IR. Motor neuronal expression of RALDH-2-IR is present in the growing axons as they extend to the periphery, indicating a potential role of retinoic acid in nerve influences on peripheral differentiation. With the exception of a transient expression in the facial/vestibulocochlear nucleus, cranial motor neurons do not express detectable levels of RALDH-2-IR.
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Affiliation(s)
- K Berggren
- Department of Anatomy and Neurobiology, University of Vermont, Burlington, Vermont, 05405, USA
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49
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Sakamoto H, Yoshida M, Uematsu K. Naturally occurring somatic motoneuron death in a teleost angelfish, Pterophyllum scalare. Neurosci Lett 1999; 267:145-8. [PMID: 10400233 DOI: 10.1016/s0304-3940(99)00353-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Naturally occurring somatic motoneuron death in a teleost angelfish, Pterophyllum scalare, was investigated histochemically and electron microscopically. The number of motor axons in the ventral root, which corresponds to the motoneuron number in spinal hemisegment, was rapidly increased beyond the adult value within 3 days after hatching, and then decreased to reach the adult value within a few weeks. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) histochemistry, which detects fragmented nuclear DNA characteristic to apoptotic cells, showed that the apoptotic cells are located in the motor column of the cord in the larvae at specific developmental stages. Electron microscopic observations of the spinal cells further confirmed the motoneuron apoptosis. The present data suggest that the massive death of somatic motoneurons at certain ontogenic stages which has been known to occur in higher vertebrates also takes place in fish.
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Affiliation(s)
- H Sakamoto
- Laboratory of Fish Physiology, Faculty of Applied Biological Science, Hiroshima University, Higashi-Hiroshima, Japan
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50
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Oppenheim RW, Homma S, Marti E, Prevette D, Wang S, Yaginuma H, McMahon AP. Modulation of early but not later stages of programmed cell death in embryonic avian spinal cord by sonic hedgehog. Mol Cell Neurosci 1999; 13:348-61. [PMID: 10356297 DOI: 10.1006/mcne.1999.0755] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sonic hedgehog (Shh) is a secreted glycoprotein expressed by the notochord and floor plate that is involved in the induction and specification of ventral phenotypes in the vertebrate neural tube. Recently, Shh has also been shown to promote the survival of cultured rat embryo ventral brain and spinal cord cells. We have examined whether Shh can promote the survival of chick embryo neurons in vivo or in vitro. In the chick, Shh is expressed in notochord, floor plate, and ventral neural tube/spinal cord at several stages at which programmed cell death (PCD) occurs. However, the administration of exogenous Shh to embryos in vivo or to motoneuron cultures at these stages failed to promote the survival of several different neuronal populations, including spinal motoneurons, spinal interneurons, sympathetic preganglionic neurons, sensory neurons, and neuronal precursor cells. Rather, at the earliest stage of PCD examined here (embryonic day 3) Shh selectively induced the death of ventral neuronal precursors and floor-plate cells, resulting in a net loss of cells in the neural tube. Altered concentrations of Shh induce aberrant phenotypes that are removed by PCD. Accordingly, normal PCD in the early neural tube may play a role in dorsal-ventral patterning.
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Affiliation(s)
- R W Oppenheim
- Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, North Carolina, 27157, USA
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