1
|
Lhospice F, Brégeon D, Belmant C, Dennler P, Chiotellis A, Fischer E, Gauthier L, Boëdec A, Rispaud H, Savard-Chambard S, Represa A, Schneider N, Paturel C, Sapet M, Delcambre C, Ingoure S, Viaud N, Bonnafous C, Schibli R, Romagné F. Site-Specific Conjugation of Monomethyl Auristatin E to Anti-CD30 Antibodies Improves Their Pharmacokinetics and Therapeutic Index in Rodent Models. Mol Pharm 2015; 12:1863-71. [PMID: 25625323 DOI: 10.1021/mp500666j] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Antibody-drug conjugates (ADCs) have demonstrated clinical benefits that have led to the recent FDA approval of KADCYLA and ADCETRIS. Most ADCs that are currently in clinical use or development, including ADCETRIS, are produced by chemical conjugation of a toxin via either lysine or cysteine residues, inevitably leading to heterogeneous products with variable drug-to-antibody ratios (DARs). Here, we describe the in vitro and in vivo characterization of four novel ADCs that are based on the anti-CD30 antibody cAC10, which has the same polypeptide backbone as ADCETRIS, and compare the results with the latter. Bacterial transglutaminase (BTG) was exploited to site-specifically conjugate derivatives of monomethyl auristatin E (all comprising a cleavable linker) to the glutamine at positions 295 and 297 of cAC10, thereby yielding homogeneous ADCs with a DAR of 4. In vitro cell toxicity experiments using two different CD30-positive cell lines (Karpas 299 and Raji-CD30(+)) revealed comparable EC50 values for ADCETRIS (1.8 ± 0.4 and 3.6 ± 0.6 ng/mL, respectively) and the four cAC10-based ADCs (2.0 ± 0.4 to 4.9 ± 1.0 ng/mL). Quantitative time-dependent in vivo biodistribution studies (3-96 h p.i.) in normal and xenografted (Karpas 299 cells) SCID mice were performed with a selected (125)I-radioiodinated cAC10 ADC and compared with that of (125)I-ADCETRIS. The chemo-enzymatically conjugated, radioiodinated ADC showed higher tumor uptake (17.84 ± 2.2% ID/g 24 h p.i.) than (125)I-ADCETRIS (10.5 ± 1.8% ID/g 24 h p.i.). Moreover, (125)I-ADCETRIS exhibited higher nontargeted liver and spleen uptake. In line with these results, the maximum tolerated dose of the BTG-coupled ADC (>60 mg/kg) was significantly higher than that of ADCETRIS (18 mg/kg) in rats. These results suggest that homogeneous ADCs display improved pharmacokinetics and better therapeutic indexes compared to those of chemically modified ADCs with variable DARs.
Collapse
Affiliation(s)
- F Lhospice
- †Innate Pharma SA, F13276 Marseille, France
| | - D Brégeon
- †Innate Pharma SA, F13276 Marseille, France
| | - C Belmant
- †Innate Pharma SA, F13276 Marseille, France
| | - P Dennler
- ‡Center for Radiopharmaceutical Sciences, ETH-PSI-USZ, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - A Chiotellis
- §Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - E Fischer
- ‡Center for Radiopharmaceutical Sciences, ETH-PSI-USZ, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - L Gauthier
- †Innate Pharma SA, F13276 Marseille, France
| | - A Boëdec
- †Innate Pharma SA, F13276 Marseille, France
| | - H Rispaud
- †Innate Pharma SA, F13276 Marseille, France
| | | | - A Represa
- †Innate Pharma SA, F13276 Marseille, France
| | | | - C Paturel
- †Innate Pharma SA, F13276 Marseille, France
| | - M Sapet
- †Innate Pharma SA, F13276 Marseille, France
| | | | - S Ingoure
- †Innate Pharma SA, F13276 Marseille, France
| | - N Viaud
- †Innate Pharma SA, F13276 Marseille, France
| | | | - R Schibli
- ‡Center for Radiopharmaceutical Sciences, ETH-PSI-USZ, Paul Scherrer Institute, 5232 Villigen, Switzerland.,§Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - F Romagné
- ∥MI-mAbs (C/0 CIML), Parc Scientifique et Technologique de Luminy, Avenue de Luminy case 906, F13288 Marseille Cedex 9, France
| |
Collapse
|
2
|
Lozovaya N, Gataullina S, Tsintsadze T, Tsintsadze V, Pallesi-Pocachard E, Minlebaev M, Goriounova NA, Buhler E, Watrin F, Shityakov S, Becker AJ, Bordey A, Milh M, Scavarda D, Bulteau C, Dorfmuller G, Delalande O, Represa A, Cardoso C, Dulac O, Ben-Ari Y, Burnashev N. Selective suppression of excessive GluN2C expression rescues early epilepsy in a tuberous sclerosis murine model. Nat Commun 2014; 5:4563. [PMID: 25081057 PMCID: PMC4143949 DOI: 10.1038/ncomms5563] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 06/30/2014] [Indexed: 01/06/2023] Open
Abstract
Tuberous sclerosis complex (TSC), caused by dominant mutations in either
TSC1 or
TSC2 tumour
suppressor genes is characterized by the presence of brain malformations, the
cortical tubers that are thought to contribute to the generation of
pharmacoresistant epilepsy. Here we report that tuberless heterozygote
Tsc1+/− mice show
functional upregulation of cortical GluN2C-containing N-methyl-D-aspartate receptors (NMDARs) in an
mTOR-dependent manner and exhibit recurrent, unprovoked seizures during early
postnatal life (<P19). Seizures are generated intracortically in the granular
layer of the neocortex. Slow kinetics of aberrant GluN2C-mediated currents in spiny stellate cells promotes
excessive temporal integration of persistent NMDAR-mediated recurrent excitation and
seizure generation. Accordingly, specific GluN2C/D antagonists block seizures in Tsc1+/− mice in vivo
and in vitro. Likewise, GluN2C expression is upregulated in TSC human surgical
resections, and a GluN2C/D
antagonist reduces paroxysmal hyperexcitability. Thus, GluN2C receptor constitutes a promising
molecular target to treat epilepsy in TSC patients. Tuberous sclerosis complex (TSC) is a rare genetic condition
characterized by epileptic seizures that start in infancy. Here, the authors show that
these seizures are modulated by GluN2C-containing NMDA receptors in the cortex of a
mouse model of TSC, and that suppressing their activity attenuates seizures.
Collapse
Affiliation(s)
- N Lozovaya
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [4]
| | - S Gataullina
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [4]
| | - T Tsintsadze
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3]
| | - V Tsintsadze
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - E Pallesi-Pocachard
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - M Minlebaev
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France [3] Laboratory of Neurobiology, Kazan Federal University, Kremlevskaya street 18, 420000 Kazan, Russia
| | - N A Goriounova
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - E Buhler
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - F Watrin
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - S Shityakov
- Department of Anaesthesia and Critical Care, University of Würzburg, Josef-Schneider-Street 2, 97080 Würzburg, Germany
| | - A J Becker
- Department of Neuropathology, University of Bonn Medical Center, Sigmund Freud Street 25, D-53105 Bonn, Germany
| | - A Bordey
- Neurosurgery, and Cellular and Molecular Physiology Departments, Yale University School of Medicine, PO Box 208082, New Haven, Connecticut 06520-8082, USA
| | - M Milh
- APHM, Department of Pediatric Neurosurgery and Neurology, CHU Timone, 264 Rue Saint-Pierre, 13385 Marseille Cedex 5, France
| | - D Scavarda
- APHM, Department of Pediatric Neurosurgery and Neurology, CHU Timone, 264 Rue Saint-Pierre, 13385 Marseille Cedex 5, France
| | - C Bulteau
- 1] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [2] Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France
| | - G Dorfmuller
- 1] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [2] Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France
| | - O Delalande
- Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France
| | - A Represa
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - C Cardoso
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - O Dulac
- 1] INSERM U1129; University Paris Descartes, CEA, Gif sur Yvette, 149 Rue de Sèvres, 75015 Paris, France [2] Department of Pediatric Neurosurgery, Foundation Rothschild, 29 Rue Manin, 75019 Paris, France [3] APHP, Necker Hospital, 149 Rue de Sèvres, 75015 Paris, France
| | - Y Ben-Ari
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| | - N Burnashev
- 1] INSERM U901, INMED, Parc Scientifique et Technologique de Luminy 163, route de Luminy-BP 13, 13273 Marseille Cedex 09, France [2] UMR901, Aix-Marseille University, 58 Boulevard Charles Livon, 13284 Marseille, France
| |
Collapse
|
3
|
Bonifazi P, Goldin M, Picardo MA, Jorquera I, Cattani A, Bianconi G, Represa A, Ben-Ari Y, Cossart R. GABAergic Hub Neurons Orchestrate Synchrony in Developing Hippocampal Networks. Science 2009; 326:1419-24. [PMID: 19965761 DOI: 10.1126/science.1175509] [Citation(s) in RCA: 439] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- P Bonifazi
- Institut de Neurobiologie de la Méditerranée INSERM U901, Universitéde la Méditerranée, Parc Scientifique de Luminy, Boîte Postale 13, 13273 Marseille Cedex 9, France
| | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Tyzio R, Cossart R, Khalilov I, Represa A, Ben-Ari Y, Khazipov R. Response to Comment on "Maternal Oxytocin Triggers a Transient Inhibitory Switch in GABA Signaling in the Fetal Brain During Delivery". Science 2007. [DOI: 10.1126/science.1141555] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
5
|
Abstract
In the present article we investigated the properties of CA1 and dentate gyrus cell precursors in adult rodents both in vivo and in vitro. Cell proliferation in situ was investigated by rating the number of cells incorporating BrdU after kainate-induced seizures. CA1 precursors displayed a greater proliferation capacity than dentate gyrus precursors. The majority of BrdU-labeled cells in CA1 expressed Nestin and Mash-1, two markers of neural precursors. BrdU-positive cells in the dentate gyrus expressed Nestin, but only a few expressed Mash-1. In animals pretreated with the antimitotic azacytidine, the capacity of kainate to enhance the proliferation was higher in CA1 than in the dentate gyrus. Differences in intrinsic progenitor cell activity could underlie these different expansion capacities. Thus, we compared the renewal- expansion and multipotency of dentate gyrus and CA1 precursors isolated in vitro. We found that the dissected CA1 region, including the periventricular zone, is enriched in neurosphere-forming cells (presumed stem cells), which respond to either EGF or FGF-2. Dentate gyrus contains fewer neurosphere-forming cells and none that respond to FGF-2 alone. Neurospheres generated from CA1 were multipotent and produced neurons, astrocytes, and oligodendrocytes, while dentate gyrus neurospheres mostly produced glial cells. The analysis of the effects of EGF on organotypic cultures of hippocampal slices depicted similar features: BrdU and Nestin immunoreactivities increased after EGF treatment in CA1 but not in the dentate gyrus. These results suggest that CA1 precursors are more stem-cell-like than granule cell precursors, which may represent a more restricted precursor cell.
Collapse
Affiliation(s)
- H Becq
- INMED/INSERM U29, Marseille, France
| | | | | | | | | |
Collapse
|
6
|
Aggoun-Zouaoui D, Margalli I, Borrega F, Represa A, Plotkine M, Ben-Ari Y, Charriaut-Marlangue C. Ultrastructural morphology of neuronal death following reversible focal ischemia in the rat. Apoptosis 2003; 3:133-41. [PMID: 14646511 DOI: 10.1023/a:1009653126347] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Electron microscopy and terminal deoxynucleotidyl transferase (TdT) mediated dUTP-biotin nick end-labelling (TUNEL) were used to illustrate the different stages and subcellular alterations of cell degeneration that occur in the striatum of the rat after transient focal ischemia. Degenerating neurons exhibited different morphological types: apoptosis Type 1 (aggregation of dense masses of chromatin beneath the 'intact' nuclear membrane) and Type 2 (high cytoplasmic vacuolization), and necrosis. These profiles were localized in different part of the striatum. Type 1 was found in the head of the caudate putamen, Type 2 in the middle part of the striatum and necrosis in the striatal core. These ultrastructural results demonstrated that apoptosis occurs in neurons following focal ischemia in the striatal penumbra. In contrast, necrosis can be observed in the ischemic core, the region maximally affected by the ischemia. Finally, the presence of astrocytes throughout both the penumbra and ischemic core displaying numerous cytoplasmic vacuoles suggested an activation of glial cells.
Collapse
Affiliation(s)
- D Aggoun-Zouaoui
- Université René Descartes, INSERM U29, 123 bd de Port-Royal, 75014 Paris, France.
| | | | | | | | | | | | | |
Collapse
|
7
|
Abstract
Several reports have suggested that neurite outgrowth is mediated by opposing forces generated on microtubules and microfilaments but the molecular basis underlying these forces have not been determined. Here, we show that in non-neuronal cell lines, the inhibition of actomyosin activity by acidic calponin promotes the formation of processes. This effect is blocked by inhibition of the motor activity of cytoplasmic dynein. Therefore, neurite formation is due to an imbalance between tensile and compressive forces mediated by myosins and dyneins, respectively. We propose a mechanism that involves the motor-mediated forces in a tight regulation of the process formation.
Collapse
Affiliation(s)
- L Ferhat
- INMED/INSERM U29, 163 rue de Luminy, BP 13, 13273 Marseille Cedex 09, France.
| | | | | | | | | |
Collapse
|
8
|
Abstract
Rat perinatal (E20-P0) CA1 pyramidal neurons were either synaptically active or silent. We show here that, during this developmental period, active but not silent cells form recurrent axon-collaterals that invade the radiatum and the lacunosum moleculare strata. These recurrents were never observed in adult rats. We propose that these transient recurrent axons may participate in the activity-dependent modulation of the synaptogenesis
Collapse
Affiliation(s)
- L Aniksztejn
- INMED-INSERM U29, Parc scientifique et technologique de Luminy, 163 Route de Luminy BP 13, 13008 Cedex, Marseille, France
| | | | | | | | | |
Collapse
|
9
|
Abstract
The adult mouse forebrain, which exhibits substantial ongoing cell genesis, contains self-renewing multipotent neural stem cells that respond to epidermal growth factor (EGF), but the adult spinal cord, which exhibits limited cell genesis, does not. Spinal cord development is a process characterized by defined periods of cell histogenesis. Thus, in the present study we asked whether EGF-responsive neural stem cells are present within the spinal cord during development. At embryonic day (E) 11, subsequent to the onset of neurogenesis, only fibroblast growth factor (FGF) receptors and FGF-2 (requiring heparan sulphate)-responsive stem cells are present in the spinal cord. Between E12 and 14, at the peak of spinal cord neurogenesis and the onset of gliogenesis, EGF receptors appear along with clonally derived highly expandable EGF-responsive neural stem cells. Following the cessation of cell histogenesis, the adult spinal cord is largely devoid of both EGF receptors and EGF-responsive stem cells. On the other hand, the FGF receptor1c subtype and multipotent FGF-2-responsive neural stem cells are present in early development and in the adult. The order of appearance of spinal cord neural stem cells and in vitro lineage analysis suggests that a more primitive FGF-2-responsive stem cell produces the EGF-responsive stem cell. These findings suggest that EGF-responsive neural stem cells appear transiently in the spinal cord, during the peak period of cell histogenesis, but are no longer present in the relatively quiescent adult structure.
Collapse
Affiliation(s)
- A Represa
- Genes & Development Research Group, Department of Cell Biology and Anatomy, University of Calgary Faculty of Medicine, 3330 Hospital Drive N.W., Calgary, AB, T2N 4N1 Canada
| | | | | | | |
Collapse
|
10
|
Abstract
Caldesmon and calponin are two actin- and calmodulin-binding proteins involved in the 'actin-linked' regulation of smooth muscle and non-muscle Mg(2+)-actin-activated myosin II ATPase activity. In the present report we show that caldesmon and calponin are present in the post-synaptic side of symmetric synapses and accumulate in the post-synaptic densities of asymmetric synapses. Caldesmon- and calponin-immunoreactivities are also observed at the plasma membrane of the hippocampal neurones. Finally, while caldesmon seems strictly distributed to neurones, acidic calponin is present in both neurones and astrocytes.
Collapse
Affiliation(s)
- C Agassandian
- INMED/INSERM U29, Parc Scientifique de Luminy, 13009 Marseille Cedex, France
| | | | | | | | | |
Collapse
|
11
|
Menn B, Timsit S, Represa A, Mateos S, Calothy G, Lamballe F. Spatiotemporal expression of noncatalytic TrkC NC2 isoform during early and late CNS neurogenesis: a comparative study with TrkC catalytic and p75NTR receptors. Eur J Neurosci 2000; 12:3211-23. [PMID: 10998105 DOI: 10.1046/j.1460-9568.2000.00215.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The TrkC subfamily of primary high-affinity neurotrophin-3 receptors is composed of catalytic (kinase-containing; TrkC K) and noncatalytic (TrkC NC) isoforms generated by alternative splicing. We previously reported the presence of the mouse noncatalytic TrkC NC2 isoform in regions of neuronal differentiation [Menn, B., Timsit, S., Calothy, G. & Lamballe, F. (1998) J. Comp. Neurol., 401, 47-64]. In order to gain insight into specific roles for TrkC NC2 receptors during CNS neurogenesis, we compared its distribution with that of its catalytic counterparts and the p75NTR receptor in in vivo and in vitro model systems of early and late neuronal differentiation. We found that TrkC NC2 expression coincided with the exit of neuronal progenitors from the cell cycle and was maintained in differentiated cerebellar neurons. We also showed that, whilst TrkC K receptors were expressed both in mitotic and postmitotic cells, TrkC NC2 was present only in differentiating neural stem cell progeny, suggesting its involvement in neuronal and glial cell differentiation. During neuritogenesis of primary neocortical neurons, both TrkC isoforms as well as p75NTR were located in axonal and dendritic processes. However, whilst these various receptors were present in the same neuronal compartments, TrkC NC2 distribution was specifically restricted to distinct areas of extending neurites. Taken together, these findings suggest that spatiotemporal localization of the noncatalytic receptor could account for specific local effects of neurotrophin-3.
Collapse
MESH Headings
- Animals
- Axons/chemistry
- Axons/enzymology
- Catalytic Domain/physiology
- Cell Differentiation/physiology
- Cells, Cultured
- Cerebellum/chemistry
- Cerebellum/embryology
- Cerebellum/enzymology
- Fluorescent Antibody Technique
- Gene Expression Regulation, Developmental
- Growth Cones/chemistry
- Growth Cones/enzymology
- Isomerism
- Mice
- Mice, Inbred C57BL
- Mitosis/physiology
- Neocortex/chemistry
- Neocortex/embryology
- Neocortex/enzymology
- Neuroglia/chemistry
- Neuroglia/cytology
- Neuroglia/enzymology
- Neurons/chemistry
- Neurons/enzymology
- Neurons/ultrastructure
- RNA, Messenger/analysis
- Rats
- Rats, Wistar
- Receptor, Nerve Growth Factor/analysis
- Receptor, Nerve Growth Factor/genetics
- Receptor, trkC/analysis
- Receptor, trkC/chemistry
- Receptor, trkC/genetics
- Stem Cells/chemistry
- Stem Cells/cytology
- Stem Cells/enzymology
Collapse
Affiliation(s)
- B Menn
- CNRS UMR 146, Institut Curie, CNRS UMR 146, Régulations Cellulaires et Oncogénèse, Centre Universitaire, Bât. 110, 91405 Orsay Cedex, France
| | | | | | | | | | | |
Collapse
|
12
|
Represa A. Molecular mechanisms of seizure-induced cerebral plasticity. Adv Neurol 1999; 81:61-7. [PMID: 10609003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- A Represa
- INSERM Unit 29, Université René Descartes, Paris, France
| |
Collapse
|
13
|
Tyzio R, Represa A, Jorquera I, Ben-Ari Y, Gozlan H, Aniksztejn L. The establishment of GABAergic and glutamatergic synapses on CA1 pyramidal neurons is sequential and correlates with the development of the apical dendrite. J Neurosci 1999; 19:10372-82. [PMID: 10575034 PMCID: PMC6782402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
We have performed a morphofunctional analysis of CA1 pyramidal neurons at birth to examine the sequence of formation of GABAergic and glutamatergic postsynaptic currents (PSCs) and to determine their relation to the dendritic arborization of pyramidal neurons. We report that at birth pyramidal neurons are heterogeneous. Three stages of development can be identified: (1) the majority of the neurons (80%) have small somata, an anlage of apical dendrite, and neither spontaneous nor evoked PSCs; (2) 10% of the neurons have a small apical dendrite restricted to the stratum radiatum and PSCs mediated only by GABA(A) receptors; and (3) 10% of the neurons have an apical dendrite that reaches the stratum lacunosum moleculare and PSCs mediated both by GABA(A) and glutamate receptors. These three groups of pyramidal neurons can be differentiated by their capacitance (C(m) = 17.9 +/- 0.8; 30.2 +/- 1.6; 43.2 +/- 3.0 pF, respectively). At birth, the synaptic markers synapsin-1 and synaptophysin labeling are present in dendritic layers but not in the stratum pyramidale, suggesting that GABAergic peridendritic synapses are established before perisomatic ones. The present observations demonstrate that GABAergic and glutamatergic synapses are established sequentially with GABAergic synapses being established first most likely on the apical dendrites of the principal neurons. We propose that different sets of conditions are required for the establishment of functional GABA and glutamate synapses, the latter necessitating more developed neurons that have apical dendrites that reach the lacunosum moleculare region.
Collapse
Affiliation(s)
- R Tyzio
- Institut de Neurobiologie de la Méditérranée, Institut National de la Santé, et de la Recherche Médicale, 13273 Marseille Cedex 09, France
| | | | | | | | | | | |
Collapse
|
14
|
Chevassus-Au-Louis N, Jorquera I, Ben-Ari Y, Represa A. Abnormal connections in the malformed cortex of rats with prenatal treatment with methylazoxymethanol may support hyperexcitability. Dev Neurosci 1999; 21:385-92. [PMID: 10575262 DOI: 10.1159/000017388] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Prenatal treatment with methylazoxymethanol (MAM) in rats generates animals with a diffuse cortical malformation associated with hyperexcitability. These alterations are reminiscent of the cortical malformations associated with epilepsy in children. We hypothesised that one of the mechanisms supporting hyperexcitability in MAM rats could be the presence of abnormal cortical connections in the malformed cortex. Using a variety of anatomical techniques, we provide evidences for three types of such abnormal connections: (i) tangential bundles of corticocortical fibres in and below the neocortical molecular layer; (ii) partial deafferentation of neocortical heterotopias by afferent cortical fibres whatever their location; (iii) exuberant innervation of hippocampal CA3 pyramidal cells by mossy fibres that form ectopic mossy boutons on their basal dendrites. We conclude that these abnormal intrinsic cortical connections may support the propagation of paroxymal activity in the neocortex of MAM-treated rats.
Collapse
|
15
|
Benjelloun N, Renolleau S, Represa A, Ben-Ari Y, Charriaut-Marlangue C. Inflammatory responses in the cerebral cortex after ischemia in the P7 neonatal Rat. Stroke 1999; 30:1916-23; discussion 1923-4. [PMID: 10471445 DOI: 10.1161/01.str.30.9.1916] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND AND PURPOSE The contribution of inflammatory response to the pathogenesis of ischemic lesions in the neonate is still uncertain. This study described the chronological sequence of inflammatory changes that follow cerebral ischemia with reperfusion in the neonatal P7 rat. METHODS P7 rats underwent left middle cerebral artery electrocoagulation associated with 1-hour left common carotid artery occlusion. The spatiotemporal pattern of cellular responses was characterized immunocytochemically with the use of antibodies against rat endogenous immunoglobulins to visualize the area of the breakdown of the blood-brain barrier. Infiltration of neutrophils and T lymphocytes was demonstrated by antibodies against myeloperoxidase and a pan-T cell marker, respectively. Antibodies ED1 and OX-42 were applied to identify microglial cells and macrophages. The response of astrocytes was shown with antibodies against glial fibrillary acidic protein. Cell survival was assessed by Bcl-2 expression. Cell death was demonstrated by DNA fragmentation with the use of the terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling (TUNEL) assay and Bax immunodetection. RESULTS Endogenous immunoglobulin extravasation through the blood-brain barrier occurred at 2 hours of recirculation and persisted until 1 month after ischemia. Neutrophil infiltration began at 24 hours and peaked at 72 to 96 hours (30+/-3.4 neutrophils per 0.3 mm(2); P<0.0001), then disappeared at 14 days after ischemia. T cells were observed between 24 and 96 hours of reperfusion. Resident microglia-macrophages exhibited morphological remnants and expressed the cell death inhibitor Bcl-2 at 24 hours of recirculation. They became numerous within the next 48 hours and peaked at 7 days after ischemia. Phenotypic changes of resident astrocytes were apparent at 24 hours, and they proliferated between 48 hours and 7 days after ischemia. Progressively inflammatory cells showed DNA fragmentation and the cell death activator Bax expression. Cell elimination continued until there was a complete disappearance of the frontoparietal cortex. CONCLUSIONS These data demonstrate that perinatal ischemia with reperfusion triggers acute inflammatory responses with granulocytic cell infiltration, which may be involved in accelerating the destructive processes.
Collapse
|
16
|
Chevassus-au-Louis N, Represa A. The right neuron at the wrong place: biology of heterotopic neurons in cortical neuronal migration disorders, with special reference to associated pathologies. Cell Mol Life Sci 1999; 55:1206-15. [PMID: 10487203 DOI: 10.1007/s000180050367] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
During the development of the neocortex, neurogenesis and neuronal differentiation occur in two separate locations. Thus neurons have to migrate through the future white matter. Arrested or excessive migration leads neurons to differentiate in a heterotopic position. Such neuronal migration disorders (NMDs) occur sporadically in normal development but are markedly increased as a consequence of genetic defects or after exposure to toxic drugs during the period of migration. Anatomofunctional studies in rodents with NMDs have revealed that heterotopic neurons form essentially normal afferent and efferent connections, which has been interpreted as evidence that the connection pattern of cortical neurons is specified prior to migration. In addition, recent data show that heterotopic neurons can be contacted by environmental, that is local, fibres that normally never innervate the neocortex. This dual connectivity leads heterotopias to form bridges between their environmental and original network. Such an abnormal pattern of connectivity could contribute to the pathophysiology of disorders associated with NMDs such as epilepsy.
Collapse
|
17
|
Plantier M, Fattoum A, Menn B, Ben-Ari Y, Der Terrossian E, Represa A. Acidic calponin immunoreactivity in postnatal rat brain and cultures: subcellular localization in growth cones, under the plasma membrane and along actin and glial filaments. Eur J Neurosci 1999; 11:2801-12. [PMID: 10457177 DOI: 10.1046/j.1460-9568.1999.00702.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Acidic calponin, an F-actin-binding protein, is particularly enriched in brain, where calponin protein and mRNA are mainly expressed by neurons. The presence of calponin immunoreactivity in cultured astroglial cells has been reported, but the presence of acidic calponin in astrocytes in vivo appears equivocal. For the present study, we raised a specific polyclonal antibody against the 16-residue synthetic peptide covering the sequence E311-Q326 (EYPDEYPREYQYGDDQ) situated at the carboxy-terminal end of rat acidic calponin, and we investigated the cellular and subcellular localization of the protein in the developing central nervous system. Our results show that acidic calponin is particularly enriched in: (i) growth cones and submembranous fields of maturing cerebellar and cortical cells, where it codistributes with microfilaments and (ii) glial cells in vivo, including radial glia, glia limitans, Bergmann glia and mature astrocytes, and ex vivo, where acidic calponin strongly colocalizes with intermediate glial fibrillary acidic protein (GFAP) and vimentin filaments. Finally, up to four acidic calponin subtypes with different isoelectric point (pI) values were identified by two-dimensional gel electrophoresis of cerebellar and hippocampal extracts. The more acidic isoforms were developmentally regulated. As only one single mRNA for acidic calponin has been identified, these isoforms must reflect postsynthesis changes probably related to the particular functions of acidic calponin in maturing cells. Although brain acidic calponin's exact role remains uncertain, the present data suggest that it is involved in neuronal and glial plasticity.
Collapse
Affiliation(s)
- M Plantier
- Université René Descartes, Paris V and INSERM U29, Paris, France
| | | | | | | | | | | |
Collapse
|
18
|
Bernard A, Ferhat L, Dessi F, Charton G, Represa A, Ben-Ari Y, Khrestchatisky M. Q/R editing of the rat GluR5 and GluR6 kainate receptors in vivo and in vitro: evidence for independent developmental, pathological and cellular regulation. Eur J Neurosci 1999; 11:604-16. [PMID: 10051761 DOI: 10.1046/j.1460-9568.1999.00479.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Kainate (KA) is a potent neuroexcitatory agent in several areas of the adult brain, with convulsant and excitotoxic properties that increase as ontogeny proceeds. Besides its depolarizing actions, KA may enhance intracellular accumulation of Ca2+ to promote selective neuronal damage. The effects of KA are mediated by specific receptors recently considered to be involved in fast neurotransmission and that can be activated synaptically. KA receptors, e.g. GluR5 and GluR6 have been characterized by molecular cloning. Structure-function relationships indicate that in the MII domain of these KA receptors, a glutamine (Q) or arginine (R) residue determines ion selectivity. The arginine stems from post-transcriptional editing of the GluR5 and GluR6 pre-RNAs, and the unedited and edited versions of GluR6 elicit distinct Ca2+ permeability. Using a PCR-based approach, we show that in vivo, Q/R editing in the GluR5 and GluR6 mRNAs is modulated during ontogeny and differs substantially in a variety of nervous tissues. GluR5 editing is highest in peripheral nervous tissue, e.g. the dorsal root ganglia, where GluR6 expression is barely detectable. In contrast, GluR6 editing is maximal in forebrain and cerebellar structures where GluR5 editing is lower. Intra-amygdaloid injections of KA provide a model of temporal lobe epilepsy, and we show that following seizures, the extent of GluR5 and GluR6 editing is altered in the hippocampus. However, in vitro, high levels of glutamate and potassium-induced depolarizations have no effect on GluR5 and GluR6 Q/R editing. GluR6 editing is rapidly enhanced to maximal levels in primary cultures of cerebellar granule neurons but not in cultured hippocampal pyramidal neurons. Finally, we show that cultured glial cells express partially edited GluR6 mRNAs. Our results indicate that Q/R editing of GluR5 and GluR6 mRNAs is structure-, cell type- and time-dependent, and suggest that editing of these mRNAs is not co-regulated.
Collapse
Affiliation(s)
- A Bernard
- Université René Descartes Paris V, INSERM Unité 29, Paris, France
| | | | | | | | | | | | | |
Collapse
|
19
|
Chevassus-Au-Louis N, Congar P, Represa A, Ben-Ari Y, Gaïarsa JL. Neuronal migration disorders: heterotopic neocortical neurons in CA1 provide a bridge between the hippocampus and the neocortex. Proc Natl Acad Sci U S A 1998; 95:10263-8. [PMID: 9707635 PMCID: PMC21496 DOI: 10.1073/pnas.95.17.10263] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neuronal migration disorders have been involved in various pathologies, including epilepsy, but the properties of the neural networks underlying disorders have not been determined. In the present study, patch clamp recordings were made from intrahippocampal heterotopic as well as from neocortical and hippocampal neurons from brain slices of rats with prenatally methylazoxymethanol-induced cortical malformation. We report that heterotopic neurons have morphometrical parameters and cellular properties of neocortical supragranular neurons and are integrated in both neocortical and hippocampal networks. Thus, stimulation of the white matter induces both antidromic and orthodromic response in heterotopic and neocortical neurons. Stimulation of hippocampal afferents evokes a monosynaptic response in the majority of heterotopic neurons and a polysynaptic all-or-none epileptiform burst in the presence of bicuculline to block gamma-aminobutyric acid type A inhibition. Furthermore, hippocampal paroxysmal activity generated by bath application of bicuculline can spread directly to the neocortex via the heterotopia in methylazoxymethanol-treated but not in naive rats. We conclude that heterotopias form a functional bridge between the limbic system and the neocortex, providing a substrate for pathological conditions.
Collapse
Affiliation(s)
- N Chevassus-Au-Louis
- Institut National de la Santé et de la Recherche Médicale U29, Université Paris 5 René Descartes, 123 Boulevard de Port Royal, 75 674 Paris cedex 14, France.
| | | | | | | | | |
Collapse
|
20
|
Chevassus-Au-Louis N, Rafiki A, Jorquera I, Ben-Ari Y, Represa A. Neocortex in the hippocampus: an anatomical and functional study of CA1 heterotopias after prenatal treatment with methylazoxymethanol in rats. J Comp Neurol 1998; 394:520-36. [PMID: 9590559 DOI: 10.1002/(sici)1096-9861(19980518)394:4<520::aid-cne9>3.0.co;2-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Migration disorders cause neurons to differentiate in an abnormal heterotopic position. Although significant insights have been gained into the etiology of these disorders, very little is known about the anatomy of heterotopias. We have studied heterotopic masses arising in the hippocampal CA1 region after prenatal treatment with methylazoxymethanol (MAM) in rats. Heterotopic cells were phenotypically similar to neocortical supragranular neurons and exhibited the same temporal profile of migration and neurogenesis. However, they did not express molecules characteristic of CA1 neurons such as the limbic-associated membrane protein. Horseradish peroxidase injections in heterotopia demonstrated labeled fibers not only in the neocortex and white matter but also in the CA1 stratum radiatum and stratum lacunosum. To study the pathophysiological consequences of this connectivity, we compared the effects of neocortical and limbic seizures on the expression of Fos protein and on cell death in MAM animals. After metrazol-induced seizures, Fos-positive cells were present in CA1 heterotopias, the only hippocampal region to be activated with the neocortex. By contrast, kainic acid-induced seizures caused a prominent delayed cell death in limbic regions and in CA1 heterotopias. Together, these results suggest that neocortical heterotopias in the CA1 region are integrated in both the hippocampal and neocortical circuitry.
Collapse
|
21
|
Plantier M, Der Terrossian E, Represa A. Beta-actin immunoreactivity in rat microglial cells: developmental pattern and participation in microglial reaction after kainate injury. Neurosci Lett 1998; 247:49-52. [PMID: 9637407 DOI: 10.1016/s0304-3940(98)00280-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the present study we investigated the developmental and post-injury pattern of beta-actin immunoreactivity in rat brain. Our data suggest that beta-actin is higher in microglia-macrophages than in any other central nervous system cell type, including neurons and astrocytes. We also show that beta-actin immunoreactivity is particularly high in ameboid-macrophagic cells, suggesting a role on the plastic changes that these cells experience during maturation or after activation.
Collapse
Affiliation(s)
- M Plantier
- Université René Descartes (Paris V) and INSERM U29, France
| | | | | |
Collapse
|
22
|
Rafiki A, Ben-Ari Y, Khrestchatisky M, Represa A. Long-lasting enhanced expression in the rat hippocampus of NMDAR1 splice variants in a kainate model of epilepsy. Eur J Neurosci 1998; 10:497-507. [PMID: 9749712 DOI: 10.1046/j.1460-9568.1998.00054.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chronic epilepsy is associated with increased excitability which may result from abnormal glutamatergic synaptic transmission involving altered properties of N-methyl-D-aspartate (NMDA) receptors. To date two gene families encoding NMDA receptor subunits have been cloned, NR1 and NR2. Eight NR1 mRNAs are generated by alternative splicing of exons 5, 21 and 22; the NR1-1 to NR1-4 C-terminal variants exist in the a or b version depending on the presence or absence of the domain encoded by exon 5. Epilepsy was induced in rats by unilateral intra-amygdalar injection of kainate and animals were killed from 6 h to 4 months following the injection. Increased NR1 mRNA levels were observed during status epilepticus (6-24 h after the injection), both psilateral and contralateral, while a second wave of NMDAR1 mRNA increase occurred in chronic epileptic animals, between 21 days and 4 months following kainate injection. Our data show: (i) a permanent increase of the NR1-2a and NR1-2b mRNA species (containing exon 22) in all hippocampal fields, both ipsilateral and contralateral, and (ii) an increase of the NR1-3 (a and b) mRNAs (containing exon 21) in the ipsilateral CA1, and NR1-3a mRNA in the ipsilateral dentate gyrus. No long-term changes were observed for the NR1-1 and NR14 splice variants. In the ipsilateral CA3 area a globally decreased mRNA expression was associated with neuronal loss. A possible contribution to the maintenance of the epileptic state by an increased expression of NMDA receptors is discussed.
Collapse
Affiliation(s)
- A Rafiki
- Université René Descartes (Paris V), France
| | | | | | | |
Collapse
|
23
|
Rafiki A, Chevassus-au-Louis N, Ben-Ari Y, Khrestchatisky M, Represa A. Glutamate receptors in dysplasic cortex: an in situ hybridization and immunohistochemistry study in rats with prenatal treatment with methylazoxymethanol. Brain Res 1998; 782:142-52. [PMID: 9519258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Injection of the antimitotic drug methylazoxymethanol (MAM) in the pregnant rat at E14 leads in the offsprings to a severe malformation with microcephaly and cortical heterotopiae in the white matter and in the CA1 field of the hippocampus. These animals suffer cognitive and epileptic disorders. Since these pathologies have been associated with glutamatergic transmission abnormalities, we have examined by in situ hybridization and immunohistochemistry the distribution and expression levels of several glutamate receptors subunits in these rats. Examination of the GluR2 flip and flop, NR1, NR2A and NR2B subunit gene transcripts showed a qualitatively similar distribution in both the neocortex and hippocampus of MAM and control rats. Quantitative analysis revealed an altered proportion of the GluR2 flip and flop subunits in the CA1 region of MAM animals as compared to controls. Moreover, a 26% reduction in the expression of the NR1 subunit and a 40% increase in the expression of the GluR2 flip subunit were noted in cortical heterotopiae, as compared to the adjacent neocortex. Immunostaining for GluR2/3, NR1 or NR2 showed, in both MAM and control animals, that glutamate receptors were mainly concentrated in the soma and dendrites of neocortical and hippocampal pyramidal cells, including in heterotopiae, and in the apical dendrites of hippocampal granule cells. Abnormalities in the expression of glutamate receptor subtypes in cortical heterotopiae and in the hippocampal CA1 region could contribute to functional disorders previously reported in MAM animals such as memory impairments and epilepsy.
Collapse
Affiliation(s)
- A Rafiki
- INSERM U29, Université Paris 5 René Descartes, France
| | | | | | | | | |
Collapse
|
24
|
Ferhat L, Represa A, Ferhat W, Ben-Ari Y, Khrestchatisky M. MAP2d mRNA is expressed in identified neuronal populations in the developing and adult rat brain and its subcellular distribution differs from that of MAP2b in hippocampal neurones. Eur J Neurosci 1998; 10:161-71. [PMID: 9753123 DOI: 10.1046/j.1460-9568.1998.00044.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The brain microtubule-associated protein MAP2 family is composed of high-molecular-weight (MAP2a and MAP2b) and low-molecular-weight (MAP2c and MAP2d) isoforms. The common C-terminal region of HMW MAP2 and MAP2c contains three repeated microtubule-binding domains while MAP2d comprises four repeats. MAP2c mRNA is known to be expressed at high levels in the immature brain. We show that in the brains of rat pups, MAP2c mRNAs are indeed expressed at high levels compared with MAP2d. However, in adult rat brains, MAP2d mRNA levels are higher than MAP2c. In order to identify the neural cells expressing MAP2d, we used in situ hybridization. In vivo, we show that MAP2d mRNA is expressed in well-identified neuronal populations of the brain. In primary cultures of hippocampal neurones, double-labelling experiments confirm that MAP2d is clearly expressed in neurones. We also evaluated in this study the subcellular distribution of the MAP2d mRNAs in cultured hippocampal neurones and we report that in contrast with MAP2b mRNAs, mostly localized in dendrites, MAP2d mRNAs are essentially located in neuronal cell bodies.
Collapse
Affiliation(s)
- L Ferhat
- Université René Descartes, Paris V, INSERM U-29, Paris, France
| | | | | | | | | |
Collapse
|
25
|
Chevassus-au-Louis N, Congar P, Ben-Ari Y, Gaïarsa JL, Represa A. Epilepsie et troubles de la migration neuronale : les hétérotopies forment des ponts entre structures normalement non connectées. Med Sci (Paris) 1998. [DOI: 10.4267/10608/949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
26
|
Rafiki A, Chevassus-au-Louis N, Ben-Ari Y, Khrestchatisky M, Represa A. Glutamate receptors in dysplasic cortex: an in situ hybridization and immunohistochemistry study in rats with prenatal treatment with methylazoxymethanol. Brain Res 1998. [DOI: 10.1016/s0006-8993(97)01273-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
27
|
Mahler M, Ben-Ari Y, Represa A. Differential expression of fibronectin, tenascin-C and NCAMs in cultured hippocampal astrocytes activated by kainate, bacterial lipopolysaccharide or basic fibroblast growth factor. Brain Res 1997; 775:63-73. [PMID: 9439829 DOI: 10.1016/s0006-8993(97)00901-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Different reports demonstrated that reactive glial cells express increased amounts of adhesion and matrix molecules. Despite a wealth of information on the expression of these molecules during development and after lesion, very little is known of how this expression is regulated. In the present report we used Western blots and immunocytochemistry to investigate the expression of neural cell adhesion molecule (NCAM), fibronectin and tenascin-C in cultured astrocytes from rat hippocampus. The effects of three different extracellular signals were analyzed: the glutamatergic receptor agonist kainic acid, the basic fibroblast growth factor (bFGF) and the bacterial lipopolysaccharide. Each treatment had a specific pattern of glial activation and differentially modified the expression of these proteins. Treatment of astrocytes with kainic acid resulted in an increase of tenascin-C, a decrease of fibronectin and a shift of NCAMs isoforms: NCAM 140 and PSA-NCAM (polysialic acid-rich NCAMs) were increased while NCAM 120 was decreased, bFGF increased fibronectin, tenascin-C and NCAM 120, while decreasing PSA-NCAM. Finally, the treatment of astrocytes with lipopolysaccharide induced a significant increase of fibronectin, tenascin-C and NCAM 120 but did not modify the expression of NCAM 140 and PSA-NCAM. These data suggest different mechanisms for modulation of cell surface interactions. They suggest that glial activation by bFGF and lipopolysaccharide are associated with an increase of the adhesive properties, while kainate action is rather associated with a decrease of the adhesiveness of astrocytes.
Collapse
Affiliation(s)
- M Mahler
- Université René Descartes, Paris V, France
| | | | | |
Collapse
|
28
|
Pollard H, Bugra K, Khrestchatisky M, Represa A, Ben-Ari Y. Seizure-induced molecular changes, sprouting and synaptogenesis of hippocampal mossy fibers. Epilepsy Res Suppl 1997; 12:355-63. [PMID: 9302535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- H Pollard
- INSERM U29, Port Royal, Paris, France
| | | | | | | | | |
Collapse
|
29
|
Abstract
Tenascin-C is an extracellular matrix glycoprotein with trophic and repulsive properties on neuronal cells, involved in migratory processes of immature neurons. Previous reports demonstrated that this molecule is produced and secreted by astrocytes, in vitro after activation by bFGF or in vivo after CNS lesion. In injured brain the expression of tenascin-C has been correlated with the glial reaction since it was observed in regions suffering a dramatic glial proliferation and hypertrophy. In this report we show that the treatment of cultured hippocampal astrocytes with tenascin-C results in an increased fibronectin and NCAM immunoreactivities. In addition, treated astrocytes form longer extensions than control ones. The number of cells as well as the levels of GFAP mRNA and protein immunoreactivity are not modified after tenascin-C treatment. The present changes may, therefore, be related to the modification of the adhesive properties of astrocytes to the substrate. These observations are compatible with the hypothesis that tenascin-C may contribute to the glial scarring process.
Collapse
Affiliation(s)
- M Mahler
- Universite René Descartes (Paris V), France
| | | | | | | |
Collapse
|
30
|
Ferhat L, Represa A, Zouaoui-Aggoun D, Ferhat W, Ben-Ari Y, Khrestchatisky M. FGF-2 induces nerve growth factor expression in cultured rat hippocampal neurons. Eur J Neurosci 1997; 9:1282-9. [PMID: 9215712 DOI: 10.1111/j.1460-9568.1997.tb01483.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Basic fibroblast growth factor (FGF-2) is expressed in the hippocampus and has been demonstrated to promote neurotrophic effects on hippocampal neurons in vitro. We show that these neurons, even at the embryonic stage, express the mRNAs encoding the FGF receptors, bek and flg. We have characterized the effects of FGF-2 on the expression of nerve growth factor (NGF) using the reverse transcription-coupled polymerase chain reaction, in situ hybridization and immunocytochemistry. In hippocampal neurons grown in the absence of serum, FGF-2 exposure induces an important elevation of NGF mRNA expression followed by a marked increase in NGF immunoreactivity. Combining in situ hybridization with an NGF probe and microtubule-associated protein-2 (MAP2) immunocytochemistry we show that the induction of NGF mRNA by FGF-2 is localized in MAP2-immunoreactive neurons. These results suggest roles for FGF-2 in the development of hippocampal neurons and in the maintenance of connections in the central nervous system, particularly the septo-hippocampal pathway, via the regulation of an important neurotrophin.
Collapse
Affiliation(s)
- L Ferhat
- Université Rene Descartes, Paris V, INSERM Unité 29, France
| | | | | | | | | | | |
Collapse
|
31
|
Abstract
The neural cell adhesion molecule (NCAM), probably the best characterized and most abundant cell adhesion molecule on neurons, is thought to be a major regulator of axonal growth and pathfinding. Here we present a detailed analysis of these processes in mice deficient for all NCAM isoforms, generated by gene targeting. The hippocampal mossy fiber tract shows prominent expression of polysialylated NCAM and the generation of new axonal projections throughout life. Focusing on this important intrahippocampal connection, we demonstrate that in the absence of NCAM, fasciculation and pathfinding of these axons are strongly affected. In addition we show alterations in the distribution of mossy fiber terminals. The phenotype is more severe in adult than in young animals, suggesting an essential role for NCAM in the maintenance of plasticity in the mature nervous system.
Collapse
Affiliation(s)
- H Cremer
- IBDM, CNRS/INSERM/Université de la Méditerranée, Marseille Cedex 9, France
| | | | | | | |
Collapse
|
32
|
Abstract
Entactin (nidogen) is a glycoprotein of 150 kDa mainly found in the basement membranes of peripheral tissues where it is co-localized and forms a very tight complex with the outgrowth-promoting molecule laminin. In the present report we tested by immunoblotting the specificity of polyclonal antibodies to laminin and entactin isolated from Engelbreth-Holm-Swarm (EHS) mouse sarcoma and investigated laminin and entactin immunoreactivities in the hippocampus of newborn, adult control and kainate-injured rats. The three polyclonal antibodies to laminin (two of them commercial) used in the present study stained somas of neurons, blood vessels and reactive glial cells, in agreement with previous reports. Nevertheless, all of them cross-reacted with entactin. The anti-entactin serum, which specifically recognized entactin protein, but not laminin or fibronectin, stained mainly the walls of blood vessels in rat brain slices. We observed a stronger entactin expression in immature than in adult brain, and a dramatic increase of vascular staining in kainate-injured hippocampus, suggesting a contribution of entactin to both development and reactive angiogenesis.
Collapse
Affiliation(s)
- J Niquet
- Université René Descartes, INSERM U29, Paris, France
| | | |
Collapse
|
33
|
Mahler M, Ferhat L, Gillian A, Ben-Ari Y, Represa A. Tenascin-C mRNA and tenascin-C protein immunoreactivity increase in astrocytes after activation by bFGF. Cell Adhes Commun 1996; 4:175-86. [PMID: 8969863 DOI: 10.3109/15419069609014221] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Tenascin-C is an extracellular matrix glycoprotein with trophic and repulsive properties, involved in migratory processes in CNS. Previous reports demonstrated that this molecule is produced and secreted by astrocytes. Preliminary data on fibroblasts and astrocytes have suggested that bFGF may modulate tenascin-C expression. bFGF is a mitogenic growth factor, involved in cell differentiation and neovascularization. In the present study, we examined whether bFGF modulates the expression of tenascin-C in hippocampal astrocytes from newborn rats. Our results suggest that bFGF increases the production of tenascin-C by cultured hippocampal astrocytes. We found that both tenascin-C mRNA and protein immunoreactivity were increased after bFGF treatment. Our results also demonstrated that tenascin-C polypeptides were secreted into the extracellular medium. In agreement with previous studies, we suggest that secreted tenascin-C is mainly the high molecular weight form. In addition, our results suggest that a cleavage of the high molecular weight form. In addition, our results suggest that a cleavage of the high molecular weight form may occur in the extracellular medium causing production of proteolytic fragments, that may modify the biological properties of tenascin-C. The present results may be relevant to the understanding of lesion scarring and regeneration process.
Collapse
Affiliation(s)
- M Mahler
- Université René Descartes (Paris V). Unité de Neurobiologie et Physiopathologie du developpement, U29 INSERM, France
| | | | | | | | | |
Collapse
|
34
|
Ferhat L, Chevassus-Au-Louis N, Khrestchatisky M, Ben-Ari Y, Represa A. Seizures induce tenascin-C mRNA expression in neurons. J Neurocytol 1996; 25:535-46. [PMID: 8910799 DOI: 10.1007/bf02284821] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Tenascin-C, an extracellular matrix glycoprotein that exhibits both growth-promoting and growth-inhibiting properties, is produced in the CNS mainly by astrocytes. In the present study we show that kainate-induced seizures result in an increased expression of tenascin-C in rat brain. Tenascin-C mRNA was increased mainly in the granule cell layer of the hippocampal complex, but tenascin-C mRNA expression was also observed in the pyriform cortex and amygdalo-cortical nucleus. Double labelling experiments using tenascin-C probes and MAP2 (a neuronal microtubule associated protein) antibodies revealed many neurons in these layers that express tenascin-C mRNA. These results support our previous findings of an increased tenascin-C immunoreactivity associated with the axons of granule cells. Tenascin-C expression is rapidly induced by seizures (6 h), preceding any lesion and glial reaction. In this pathological condition tenascin-C appears to be produced by both glia and neurons. The functional repercussions on the scarring and remodelling processes are also discussed.
Collapse
Affiliation(s)
- L Ferhat
- Université René Descartes, Paris V, INSERM U29, France
| | | | | | | | | |
Collapse
|
35
|
Ferhat L, Charton G, Represa A, Ben-Ari Y, der Terrossian E, Khrestchatisky M. Acidic calponin cloned from neural cells is differentially expressed during rat brain development. Eur J Neurosci 1996; 8:1501-9. [PMID: 8758957 DOI: 10.1111/j.1460-9568.1996.tb01612.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Calponin is an actin-, tropomyosin- and Ca2+ calmodulin-binding protein that inhibits in vitro the actomyosin MgATPase. Basic and acidic variants of calponin have been described to date. Although the cerebral expression of calponin remained controversial for some time, transcripts encoding acidic calponin in the adult rat brain and in cultured cerebellar cells have been reported. In the present work, we report the expression of acidic calponin mRNAs and the isolation of cDNAs encoding the full-length acidic calponin in cultured neuronal and glial cells and in adult rat brain. Sequence analysis reveals that acidic calponin in the brain is identical to that previously described in rat aortic vascular smooth muscle. In situ hybridization shows that calponin is highly expressed during ontogenesis in granule cells of the dentate gyrus of the hippocampus, in all layers of the olfactory bulb and in cerebellar granule neurons of the external and internal layers. In the adult rat brain, calponin expression decreased in these fields, but increased in choroid plexus cells. Bergmann glial cells were also labelled by a calponin probe. The reverse transcription-coupled polymerase chain reaction confirms that calponin mRNA levels are highest in the early stages of hippocampal development and that expression levels are low in adult hippocampi. The developmental expression pattern of brain acidic calponin suggests that calponin could be involved in contractile activity associated with neural cell proliferation or neuronal migration.
Collapse
Affiliation(s)
- L Ferhat
- Université René Descartes, Paris V, INSERM U29, 123 Bld de Port Royal,75014 Paris, France
| | | | | | | | | | | |
Collapse
|
36
|
Ferhat L, Represa A, Bernard A, Ben-Ari Y, Khrestchatisky M. MAP2d promotes bundling and stabilization of both microtubules and microfilaments. J Cell Sci 1996; 109 ( Pt 5):1095-103. [PMID: 8743956 DOI: 10.1242/jcs.109.5.1095] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two low molecular weight MAP2 variants have been described, MAP2c and MAP2d. These variants are produced from a single gene by alternative splicing, and in their C-terminal regions contain, respectively, 3 and 4 tandem repeats, some of which are known to be involved in binding to microtubules. Substantial differences in the developmental expression pattern of MAP2c and MAP2d suggest they have different functions in neural cells. In order to investigate the respective roles of these MAP2 variants, we have analyzed the effects of MAP2c and MAP2d expression on microtubule and microfilament organization in transiently transfected cells. Our results show that both variants stabilize microtubules, but only MAP2d stabilizes microfilaments.
Collapse
Affiliation(s)
- L Ferhat
- Université René Descartes, Paris V, INSERM Unité 29, France
| | | | | | | | | |
Collapse
|
37
|
Abstract
Injection of kainic acid into the amygdala induces in addition to a local cell loss a seizure related distal damage of the hippocampal complex, in particular in the CA3 field and hilus. This neuronal lesion is associated with hypertrophy and proliferation of astroglial cells which start around 3 days after kainate and peaks within 20 days of kainate. We now report that reactive astrocytes are labelled with antibodies against vitronectin in the CA3 field and hilus. In the present study we also exclude that the presence of vitronectin into the brain is due to an extravasation from serum throughout a blood brain barrier leakage. The present results constitute the first demonstration for a glial expression of vitronectin in vivo. Vitronectin is an extracellular matrix glycoprotein involved in axonal growth. The glial expression of vitronectin may therefore contribute to the synaptic remodeling of mossy fibers induced in the hippocampus by such treatment.
Collapse
Affiliation(s)
- J Niquet
- Université René Descartes (Paris V), INSERUM U29, Paris, France
| | | | | | | |
Collapse
|
38
|
Charriaut-Marlangue C, Aggoun-Zouaoui D, Represa A, Ben-Ari Y. Apoptotic features of selective neuronal death in ischemia, epilepsy and gp 120 toxicity. Trends Neurosci 1996; 19:109-14. [PMID: 9054057 DOI: 10.1016/s0166-2236(96)80039-7] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The occurrence of physiological cell death has been known for decades, but interest in the subject was renewed in 1972 when Kerr, Wyllie and Currie described in detail the ultrastructural changes characteristic of dying cells and coined the term apoptosis to describe the process. Cells display a wide variety of morphological changes when dying during development or following a toxic insult. A binary classification scheme suggests that physiologically appropriate death is due to apoptosis and that pathological mechanisms involve necrosis. However, recent studies indicate a potential involvement of apoptotic cell death in ischemia, status epilepticus and HIV-1 infection.
Collapse
|
39
|
Charriaut-Marlangue C, Margaill I, Represa A, Popovici T, Plotkine M, Ben-Ari Y. Apoptosis and necrosis after reversible focal ischemia: an in situ DNA fragmentation analysis. J Cereb Blood Flow Metab 1996; 16:186-94. [PMID: 8594049 DOI: 10.1097/00004647-199603000-00002] [Citation(s) in RCA: 279] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Apoptosis is one of the two forms of cell death and occurs under a variety of physiological and pathological conditions. Cells undergoing apoptotic cell death reveal a characteristic sequence of cytological alternations including membrane blebbing and nuclear and cytoplasmic condensation. Early activation of an endonuclease has been previously demonstrated after a transient focal ischemia in the rat brain Charriaut-Marlangue C, Margaill I, Plotkine M, Ben-Ari Y (1995) Early endonuclease activation following reversible focal ischemia. J Cereb Blood Flow Metab 15:385-388). We now show that a significant number of striatal and cortical neurons, exhibited chromatin condensation, nucleus segmentation, and apoptotic bodies increasing with recirculation time, as demonstrated by in situ labeling of DNA breaks in cryostat sections. Apoptotic nuclei were also detected in the horizontal limb diagonal band, accumbens nucleus and islands of Calleja. Several necrotic neurons, in which random DNA fragmentation occurs, were also shown at 6 h recirculation, in the ischemic core. Further investigation with hematoxylin/eosin staining revealed that apoptotic nuclei were present in cells with a large and swelled cytoplasm and in cells with an apparently well-preserved cytoplasm. These two types of cell death were reminiscent of those described in developmental cell death. Our data suggested that apoptosis may contribute to the expansion of the ischemic lesion.
Collapse
|
40
|
Aggoun-Zouaoui D, Charriaut-Marlangue C, Rivera S, Jorquera I, Ben-Ari Y, Represa A. The HIV-1 envelope protein gp120 induces neuronal apoptosis in hippocampal slices. Neuroreport 1996; 7:433-6. [PMID: 8730799 DOI: 10.1097/00001756-199601310-00014] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The HIV-1 envelope protein gp120 produces neuronal cell damage in primary cultures of a variety of cell types including hippocampal and retinal ganglion cell neurons. The properties of primary cell cultures are, however, often markedly different from those of cells living in their normal environment. We now report that gp120 induces widespread chromatin condensation and lesions in pyramidal granular neurones and in interneurones of rat hippocampal organotypic slice cultures. This damage is clearly of an apoptotic (programmed cell death) type. The use of an in vitro organized structure will enable the molecular and cellular mechanism of action of gp120 to be examined in conditions which are particularly suitable and relevant to the in vivo situation.
Collapse
|
41
|
Ferhat L, Chevassus au Louis N, Jorquera I, Niquet J, Khrestchatisky M, Ben-Ari Y, Represa A. Transient increase of tenascin-C in immature hippocampus: astroglial and neuronal expression. J Neurocytol 1996; 25:53-66. [PMID: 8852938 DOI: 10.1007/bf02284785] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In the present report we describe the anatomical localization of cells expressing tenascin-C, an extracellular matrix glycoprotein, in the hippocampal complex of developing rats. We report a development-dependent down regulation of both tenascin-C protein and mRNA. The highest levels of expression of tenascin-C was observed in rat pups from embryonic day 18 to postnatal day 7. Double labelling experiments performed with a tenascin-C antibody or tenascin-C probes combined with specific markers of astrocytes (GFAP) or neurons (MAP2 and Tau) allowed us to demonstrate that tenascin-C is expressed by both immature astrocytes and neurons in immature hippocampus. The temporal and topographic distribution of cells expressing tenascin-C (in the hilus and the stratum oriens of CA3) correlate with the localization and period of migration and maturation of post-mitotic cells. In view of these data we discuss the hypothesis that tenascin-C, as a mediator of neuron-glia interactions, may contribute to the development of hippocampal cells.
Collapse
Affiliation(s)
- L Ferhat
- Université René Descartes (Paris V), INSERM U29, France
| | | | | | | | | | | | | |
Collapse
|
42
|
Aggoun D, Medina I, Ghose S, Ben-Ari Y, Represa A. Le virus VIH-1 et la mort neuronale : étude des effets de la protéine de l'enveloppe virale gp120. Med Sci (Paris) 1996. [DOI: 10.4267/10608/801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
43
|
Represa A, Trabelsi-Terzidis H, Plantier M, Fattoum A, Jorquera I, Agassandian C, Ben-Ari Y, der Terrossian E. Distribution of caldesmon and of the acidic isoform of calponin in cultured cerebellar neurons and in different regions of the rat brain: an immunofluorescence and confocal microscopy study. Exp Cell Res 1995; 221:333-43. [PMID: 7493632 DOI: 10.1006/excr.1995.1383] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Caldesmon and calponin are two F-actin-binding and calcium-calmodulin-dependent proteins. In smooth muscle and nonmuscle cells both proteins are localized on actin filaments. Using one- or two-dimensional gel electrophoresis followed by the Western blot technique, and by immunofluorescence studies, we have given evidence that calponin is also present in rat and pig brain. In the present study, for the first time, we demonstrate caldesmon- and calponin-specific immunoreactivities in cerebellar cultured neurons. In the rat central nervous system these antibodies mainly stain neuronal cell bodies and dendrites. By confocal analysis we observed that calponin and caldesmon are located in the actomyosin domain although the total actin and myosin were not saturated. In many cases it is clear that these two proteins are adjacent rather than superimposed in the same domain of the cell. These results are compatible with the functional role of caldesmon and calponin in the regulation of the actomyosin activity as described by others and suggest that they are part of the contractile apparatus of neural cells.
Collapse
Affiliation(s)
- A Represa
- Université René Descartes, Paris V, France
| | | | | | | | | | | | | | | |
Collapse
|
44
|
Niquet J, Jorquera I, Faissner A, Ben-Ari Y, Represa A. Gliosis and axonal sprouting in the hippocampus of epileptic rats are associated with an increase of tenascin-C immunoreactivity. J Neurocytol 1995; 24:611-24. [PMID: 7595669 DOI: 10.1007/bf01257376] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Temporal lobe epilepsy is associated with neuronal death, gliosis and sprouting of mossy fibres in the hippocampus of human and rats. In the present study we show that immunoreactivity for tenascin-C (an extracellular matrix glycoprotein) increase in the hippocampus of epileptic rats. However, this increase was only observed in the cases displaying neuronal cell loss and glial reaction (i.e. after kainate treatment but not after kindling). Tenascin-C increase was particularly striking at Ammon's horn, where the antibody labelled both reactive astrocytes (confirmed by double-labelling experiments) and axonal plasma membranes. In the molecular layer tenascin-C immunoreactivity remained unchanged in both kindled or kainate treated rats. It is interesting that increased tenascin-C immunoreactivity was observed within zones in which axonal regeneration did not occur (the CA3 area in kainate-treated animals) whereas zones in which reactive synaptogenesis occurred (such as the CA3 area of kindled rats or the molecular layer of both kindled and kainate-treated rats) were devoid of tenascin-C immunoreactivity. We infer from these results that tenascin-C impedes the terminal sprouting of mossy fibres in CA3 of kainate-treated rats.
Collapse
Affiliation(s)
- J Niquet
- Université René Descartes (Paris V), INSERM U29, France
| | | | | | | | | |
Collapse
|
45
|
Khrestchatisky M, Ferhat L, Charton G, Bernard A, Pollard H, Represa A, Ben-Ari Y. Molecular correlates between reactive and developmental plasticity in the rat hippocampus. J Neurobiol 1995; 26:426-36. [PMID: 7775975 DOI: 10.1002/neu.480260314] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Area CA3 of the hippocampus is the most epileptogenic structure of the brain. Various studies have shown that kainate-induced experimental epilepsy in rats and human cases of epilepsy are associated with sprouting of the mossy fibers of the dentate granule neurons and selective loss of pyramidal neurons, notably in the CA3-CA4 areas of Ammon's horn. In experimental models of epilepsy, brief seizure activity initiates a cascade of molecular alterations that will contribute to changes in the expression of numerous genes, which can last several weeks. The products of some of these genes will contribute to the permanent state of enhanced synaptic efficiency, to the sprouting and formation of novel excitatory synapses, and possibly to neuronal cell loss. The expression of genes encoding transcription factors and numerous growth factors is rapidly altered following seizure episodes. Based on observations in vivo and in vitro in cultured hippocampal neurons, it is hypothesized that an interplay between transcription and growth factors, because of their pleiotropic effects on the regulation of effector genes, may be instrumental in coupling transient extracellular stimuli to irreversible cellular alterations.
Collapse
|
46
|
Abstract
Seizures set in motion complex molecular and morphological changes in vulnerable structures, such as the hippocampal complex. A number of these changes are responsible for neuronal death of CA3 and hilar cells, which involves necrotic and apoptotic mechanisms. In surviving dentate granule cells seizures induce an increased expression of tubulin subunits and microtubule-associated proteins, suggesting that an overproduction of tubulin polymers would lead to a remodeling of mossy fibers (the axons of granule cells). In fact, these fibers sprout in the dentate gyrus to innervate granule cell dendrites, creating recurrent excitatory circuits. In contrast, terminal mossy fibers do not sprout in the CA3 field. Navigation of mossy fiber's growth cones may be facilitated by astrocytes, which would exert differential effects by producing and excreting cell adhesion and substrate molecules. In the light of the results discussed here, we suggest that in adult brain activated-resident astrocytes (nonproliferating, tenascin-negative, neuronal cell-adhesion molecule-positive astrocytes) could contribute to the process of axonal outgrowth and synaptogenesis in the dentate gyrus, while proliferating astrocytes, tenascin-positive, could impede any axonal rearrangement in CA3.
Collapse
Affiliation(s)
- A Represa
- INSERM U29, Hôpital de Port Royal, Paris, France
| | | | | | | |
Collapse
|
47
|
Trabelsi-Terzidis H, Fattoum A, Represa A, Dessi F, Ben-Ari Y, der Terrossian E. Expression of an acidic isoform of calponin in rat brain: western blots on one- or two-dimensional gels and immunolocalization in cultured cells. Biochem J 1995; 306 ( Pt 1):211-5. [PMID: 7864813 PMCID: PMC1136503 DOI: 10.1042/bj3060211] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Calponin, an actin- and Ca(2+)-calmodulin-binding protein characterized as an inhibitory factor of the smooth-muscle actomyosin activity, has also been shown to be present in some non-muscle cells. However, there is a controversy as to whether calponin is present or not in brain. Several laboratories indicate that this protein is absent in chicken or bovine brains, while Applegate et al. [Applegate, Feng, Green and Taubman (1994) J. Biol. Chem. 269, 10683-10690] have recently reported the identification of an mRNA specific for a 36 kDa non-muscle calponin analogue in homogenates of rat brains. For the first time we demonstrate, by Western blots and in situ immunofluorescence localization using monoclonal as well as affinity-purified polyclonal antibody to gizzard calponin, that a 36-37 kDa and a 35-36 kDa calponin-like proteins are expressed respectively in pig and rat brains and in rat cerebellar cultured cells. The acidic pI (5.2-5.4) of the rat brain protein revealed by isoelectric focusing is in good agreement with that of the protein coded for by the calponin isoform mRNA described by Applegate et al. and is different from that of the protein from chicken gizzard (pI 9.9). Brain calponin-like protein is different from two other Ca(2+)-calmodulin-binding proteins previously identified in brain, namely caldesmon and adducin, and from tropomyosin.
Collapse
|
48
|
Abstract
We have examined the role apoptosis plays in epileptic brain damage using intra-amygdaloid injection of kainate. With the silver staining technique of Gallyas, argyrophylic (dying) neurons were observed, a few hours after the injection, in the amygdala and in the vulnerable pyramidal neurons of the hippocampal CA3 region. In both areas, cell death has apoptotic features, including: (i) nuclear chromatin condensation and marginalization with light and electron microscopy; (ii) DNA fragmentation with a typical ladder pattern on agarose gel electrophoresis; (iii) positive nuclear labelling with a selective in situ DNA fragmentation staining method. Combined in situ DNA labelling and silver staining showed that the DNA fragmentation occurred in dying neurons. CA1 or granule cells which do not degenerate following intra-amygdaloid injection of kainate were not stained with the in situ DNA labelling or the argyrophylic technique. Administration of diazepam blocked the kainate-induced seizures and prevented DNA fragmentation in CA3 but not in the amygdala. Therefore, apoptosis contributes to the local and distant damage induced by kainate.
Collapse
Affiliation(s)
- H Pollard
- INSERM U 29, Laboratoire de Neurobiologie et Physiopathologie du Développement, Hopital de Port Royal, Paris, France
| | | | | | | | | | | | | |
Collapse
|
49
|
Abstract
Kainic acid treatment, a model of temporal lobe epilepsy, induces in CA3-CA4 fields of hippocampal complex a neuronal degeneration associated with glial hypertrophy and proliferation. After treatment with kainate, fibronectin (an extracellular matrix protein) immunoreactivity increases in CA3-CA4. Fibronectin antibodies stain proliferative cells (simultaneously labelled by [3H]thymidin) of astrocytic type (double-immunostained by GFAP antibodies). This result constitutes the first direct demonstration of astroglial fibronectin expression in vivo. In the molecular layer of kainate-treated rats there is an axon-terminal degeneration of association-fibers. This is associated with a transient hypertrophy of resident astrocytes but not with any glial proliferation. Reactive astrocytes do not express (or faintly) fibronectin immunoreactivity in this layer. Since fibronectin is involved in astroglial proliferation in vitro, the present observations suggest that astrocytes contribute in vivo to the astroglial proliferation by an autocrin mechanism.
Collapse
Affiliation(s)
- J Niquet
- Université René Descartes-Paris V, INSERM U29, Paris, France
| | | | | | | |
Collapse
|
50
|
Niquet J, Ben-Ari Y, Represa A. Glial reaction after seizure induced hippocampal lesion: immunohistochemical characterization of proliferating glial cells. J Neurocytol 1994; 23:641-56. [PMID: 7836958 DOI: 10.1007/bf01191558] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Kainic acid treatment (a model of temporal lobe epilepsy) induces Ammon's horn sclerosis, which is characterized by degeneration of CA3 pyramidal neurons and reactive gliosis. In the present study we have combined autoradiographic analysis of 3H-thymidine incorporation and immunocytochemistry to investigate this glial scarring phenomenon. The present results demonstrate that in the fields showing neuronal degeneration (i.e. CA3-CA4 fields of Ammon's horn and dentate hilus) the glial reaction consists of a proliferation and hypertrophy of astrocytes and microglia-macrophages. In the regions showing exclusively terminal axonal degeneration (i.e. the molecular layer of kainate-treated rats), glial cells do not proliferate but astrocytes show a transient hypertrophy. These results also demonstrate that oligodendrocytes do not proliferate in the hippocampus of kainate-treated rats. In agreement with our previous report we find that hippocampal astrocytes from kainate-treated rats express A2B5 immunoreactivity, a marker of type-2 astrocytes. A2B5 immunoreactivity was expressed by astrocytes not only in areas showing glial proliferation such as CA3-CA4 fields, but also in the molecular layer, where astrocytes do not proliferate. This suggests that in the CNS, normal resident astrocytes acquire the phenotypic properties of type-2 astrocytes.
Collapse
|