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Thibert C, Lucas A, Billaud M, Torch S, Mével-Aliset M, Allard J. Functions of LKB1 in neural crest development: the story unfolds. Dev Dyn 2023. [PMID: 36880501 DOI: 10.1002/dvdy.581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 02/20/2023] [Accepted: 02/20/2023] [Indexed: 03/08/2023] Open
Abstract
Neural crest cells (NCCs) are highly motile, multipotent, embryonic cells that delaminate from the dorsal edges of the neural tube. NCCs follow stereotypical long-range migratory pathways to reach target organs during development, where they give rise to multiple derivatives. The identification of reservoirs of neural crest stem cells that persist to adulthood has recently aroused renewed interest in the biology of NCCs. In this context, several recent studies have demonstrated the essential role of the metabolic kinase LKB1 in NCC establishment. This review surveys how LKB1 governs the formation and maintenance of several neural crest derivatives, including facial bones, melanocytes, Schwann cells, and the enteric nervous system. We also detail the underlying molecular mechanisms that involve downstream effectors of LKB1, in particular the contribution of the AMPK-mTOR signaling pathway to both polarity and metabolic processes. Collectively, these recent discoveries open promising perspectives for new therapeutic applications for the treatment of neural crest disorders. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Chantal Thibert
- Univ. Grenoble Alpes, INSERM 1209, CNRS 5309, Institute for Advanced Biosciences, Grenoble, France
| | - Anthony Lucas
- Univ. Grenoble Alpes, INSERM 1209, CNRS 5309, Institute for Advanced Biosciences, Grenoble, France
| | - Marc Billaud
- Cell death and Childhood Cancers team, Cancer Research Center of Lyon, INSERM U1052, CNRS UMR5286, University of Lyon, Centre Léon Bérard, Lyon, France
| | - Sakina Torch
- Univ. Grenoble Alpes, INSERM 1209, CNRS 5309, Institute for Advanced Biosciences, Grenoble, France
| | - Marie Mével-Aliset
- Univ. Grenoble Alpes, INSERM 1209, CNRS 5309, Institute for Advanced Biosciences, Grenoble, France
| | - Jordan Allard
- Univ. Grenoble Alpes, INSERM 1209, CNRS 5309, Institute for Advanced Biosciences, Grenoble, France
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2
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Radu AG, Torch S, Fauvelle F, Pernet-Gallay K, Lucas A, Blervaque R, Delmas V, Schlattner U, Lafanechère L, Hainaut P, Tricaud N, Pingault V, Bondurand N, Bardeesy N, Larue L, Thibert C, Billaud M. LKB1 specifies neural crest cell fates through pyruvate-alanine cycling. Sci Adv 2019; 5:eaau5106. [PMID: 31328154 PMCID: PMC6636984 DOI: 10.1126/sciadv.aau5106] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 06/10/2019] [Indexed: 05/08/2023]
Abstract
Metabolic processes underlying the development of the neural crest, an embryonic population of multipotent migratory cells, are poorly understood. Here, we report that conditional ablation of the Lkb1 tumor suppressor kinase in mouse neural crest stem cells led to intestinal pseudo-obstruction and hind limb paralysis. This phenotype originated from a postnatal degeneration of the enteric nervous ganglia and from a defective differentiation of Schwann cells. Metabolomic profiling revealed that pyruvate-alanine conversion is enhanced in the absence of Lkb1. Mechanistically, inhibition of alanine transaminases restored glial differentiation in an mTOR-dependent manner, while increased alanine level directly inhibited the glial commitment of neural crest cells. Treatment with the metabolic modulator AICAR suppressed mTOR signaling and prevented Schwann cell and enteric defects of Lkb1 mutant mice. These data uncover a link between pyruvate-alanine cycling and the specification of glial cell fate with potential implications in the understanding of the molecular pathogenesis of neural crest diseases.
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Affiliation(s)
- Anca G. Radu
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Sakina Torch
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Florence Fauvelle
- Univ. Grenoble Alpes, INSERM, U1216, Grenoble Institute of Neurosciences GIN, 38000 Grenoble, France
- Univ. Grenoble Alpes, INSERM, US17, MRI facility IRMaGe, 38000 Grenoble, France
| | - Karin Pernet-Gallay
- Univ. Grenoble Alpes, INSERM, U1216, Grenoble Institute of Neurosciences GIN, 38000 Grenoble, France
| | - Anthony Lucas
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Renaud Blervaque
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Véronique Delmas
- Institut Curie, Normal and Pathological Development of Melanocytes, CNRS UMR3347; INSERM U1021; Equipe Labellisée–Ligue Nationale Contre le Cancer, Orsay, France
| | - Uwe Schlattner
- Laboratory of Fundamental and Applied Bioenergetics, Univ Grenoble Alpes, 38185 Grenoble, France
- INSERM U1055, 38041 Grenoble France
| | - Laurence Lafanechère
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Pierre Hainaut
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38000 Grenoble, France
| | - Nicolas Tricaud
- INSERM U1051, Institut des Neurosciences de Montpellier (INM), Université de Montpellier, Montpellier, France
| | | | | | - Nabeel Bardeesy
- Cancer Center, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA
- Center for Regenerative Medicine, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Lionel Larue
- Institut Curie, Normal and Pathological Development of Melanocytes, CNRS UMR3347; INSERM U1021; Equipe Labellisée–Ligue Nationale Contre le Cancer, Orsay, France
| | - Chantal Thibert
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38000 Grenoble, France
- Corresponding author. (M.B.); (C.T.)
| | - Marc Billaud
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38000 Grenoble, France
- “Clinical and experimental model of lymphomagenesis” Univ Lyon, Université Claude Bernard Lyon1, INSERM 1052, CNRS 5286, Centre Léon Bérard, Centre de recherche en cancérologie de Lyon, Lyon France
- Corresponding author. (M.B.); (C.T.)
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3
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Creuzet SE, Viallet JP, Ghawitian M, Torch S, Thélu J, Alrajeh M, Radu AG, Bouvard D, Costagliola F, Borgne ML, Buchet-Poyau K, Aznar N, Buschlen S, Hosoya H, Thibert C, Billaud M. LKB1 signaling in cephalic neural crest cells is essential for vertebrate head development. Dev Biol 2016; 418:283-96. [DOI: 10.1016/j.ydbio.2016.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 07/19/2016] [Accepted: 08/06/2016] [Indexed: 11/25/2022]
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4
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Mahul-Mellier AL, Strappazzon F, Petiot A, Chatellard-Causse C, Torch S, Blot B, Freeman K, Kuhn L, Garin J, Verna JM, Fraboulet S, Sadoul R. Alix and ALG-2 are involved in tumor necrosis factor receptor 1-induced cell death. J Biol Chem 2008; 283:34954-65. [PMID: 18936101 PMCID: PMC3259881 DOI: 10.1074/jbc.m803140200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Revised: 10/01/2008] [Indexed: 12/29/2022] Open
Abstract
Alix/AIP1 regulates cell death in a way involving interactions with the calcium-binding protein ALG-2 and with proteins of ESCRT (endosomal sorting complex required for transport). Using mass spectrometry we identified caspase-8 among proteins co-immunoprecipitating with Alix in dying neurons. We next demonstrated that Alix and ALG-2 interact with pro-caspase-8 and that Alix forms a complex with the TNFalpha receptor-1 (TNF-R1), depending on its capacity to bind ESCRT proteins. Thus, Alix and ALG-2 may allow the recruitment of pro-caspase-8 onto endosomes containing TNF-R1, a step thought to be necessary for activation of the apical caspase. In line with this, expression of Alix deleted of its ALG-2-binding site (AlixDeltaALG-2) significantly reduced TNF-R1-induced cell death, without affecting endocytosis of the receptor. In a more physiological setting, we found that programmed cell death of motoneurons, which can be inhibited by AlixDeltaALG-2, is regulated by TNF-R1. Taken together, these results highlight Alix and ALG-2 as new actors of the TNF-R1 pathway.
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Affiliation(s)
- Anne-Laure Mahul-Mellier
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Flavie Strappazzon
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Anne Petiot
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Christine Chatellard-Causse
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Sakina Torch
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Béatrice Blot
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Kimberley Freeman
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Loriane Kuhn
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Jérome Garin
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Jean-Marc Verna
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Sandrine Fraboulet
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
| | - Rémy Sadoul
- INSERM, U836, Equipe 2,
Neurodégénérescence et Plasticité, Grenoble
F-38042, France, Commissariat à
l'Énergie Atomique, Departement des Sciences du Vivant Laboratoire
d'Etude de la Dynamique des Protéomes, Grenoble F-38054, France,
INSERM, U880, Grenoble F-38054, France, and the
Université Joseph Fourier, Grenoble
Institut des Neurosciences, Grenoble F-38042, France
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Petiot A, Strappazzon F, Chatellard-Causse C, Blot B, Torch S, Verna JM, Sadoul R. Alix differs from ESCRT proteins in the control of autophagy. Biochem Biophys Res Commun 2008; 375:63-8. [PMID: 18684393 DOI: 10.1016/j.bbrc.2008.07.136] [Citation(s) in RCA: 12] [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] [Received: 07/03/2008] [Accepted: 07/22/2008] [Indexed: 11/25/2022]
Abstract
Alix/AIP1 is a cytosolic protein that regulates cell death through mechanisms that remain unclear. Alix binds to two protein members of the so-called Endosomal Sorting Complex Required for Transport (ESCRT), which facilitates membrane fission events during multivesicular endosome formation, enveloped virus budding and cytokinesis. Alix itself has been suggested to participate in these cellular events and is thus often considered to function in the ESCRT pathway. ESCRT proteins were recently implicated in autophagy, a process involved in bulk degradation of cytoplasmic constituents in lysosomes, which can also participate in cell death. In this study, we shown that, unlike ESCRT proteins, Alix is not involved in autophagy. These results strongly suggest that the capacity of several mutants of Alix to block both caspase-dependent and independent cell death does not relate to their capacity to modulate autophagy. Furthermore, they reinforce the conclusion of other studies demonstrating that the role of Alix is different from that of classical ESCRT proteins.
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Affiliation(s)
- Anne Petiot
- INSERM U836, Grenoble Institute of Neuroscience, F-38042 Grenoble, France.
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6
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Strappazzon F, Torch S, Trioulier Y, Blot B, Sadoul R, Verna JM. Survival response-linked Pyk2 activation during potassium depletion-induced apoptosis of cerebellar granule neurons. Mol Cell Neurosci 2006; 34:355-65. [PMID: 17188509 DOI: 10.1016/j.mcn.2006.11.012] [Citation(s) in RCA: 7] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Revised: 10/27/2006] [Accepted: 11/14/2006] [Indexed: 11/16/2022] Open
Abstract
Numerous extracellular stimuli trigger trans-autophosphorylation at Tyr402 of Pyk2, inducing its activation. Pyk2 is a key mediator of several signaling pathways and has been implicated in apoptosis induced by specific stress signals. We investigated whether Pyk2 participates in cerebellar granule neuron (CGN) apoptosis induced by the suppression of membrane depolarization. We demonstrate that shifting CGN cultures from 25 mM to 5 mM KCl-containing medium induces an early, transient 70% increase in phosphorylated Tyr402 and Tyr580 Pyk2 levels that is triggered by Ca(2+) released from intracellular stores and mediated by calmodulin (CaM). Overexpression of Pyk2 increases CGN survival after 24 h by 70% compared to the control, thus suggesting that Pyk2 is involved in an anti-apoptotic response to K+ lowering. Furthermore, we show that CGN grown in K25 medium exhibit detectable CaM-dependent Pyk2 activity. When silencing Pyk2 activity by expressing a dominant-negative form, only 40% of the transfected neurons were alive 24 h after transfection when compared to the control. Overall, the present findings demonstrate for the first time that Pyk2 is a critical mediator of CGN survival.
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Affiliation(s)
- Flavie Strappazzon
- Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire Neurodégénérescence et Plasticité, EMI108, France
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7
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Blum D, Hemming FJ, Galas MC, Torch S, Cuvelier L, Schiffmann SN, Sadoul R. Increased Alix (apoptosis-linked gene-2 interacting protein X) immunoreactivity in the degenerating striatum of rats chronically treated by 3-nitropropionic acid. Neurosci Lett 2005; 368:309-13. [PMID: 15364417 DOI: 10.1016/j.neulet.2004.07.046] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2004] [Revised: 07/15/2004] [Accepted: 07/15/2004] [Indexed: 10/26/2022]
Abstract
Chronic intoxication by 3-nitropropionic acid in the Lewis rat reproduces many features reminiscent of Huntington's disease including behavioural alterations and cortico-striatal degeneration. In particular, in this model, striatal degeneration is accompanied by calpain activation as found in the human disease. The present study was undertaken to determine whether the expression of Alix (apoptosis linked gene-2 interacting protein), a widespread protein involved in neuronal death, would be modified in the striatum and cortex of 3NP-treated rats. The results clearly show that Alix immunoreactivity is increased in the neuronal cell bodies of the lateral striatum, where degeneration is massive. The medial striatum and the cortex that lack neurodegeneration remain only weakly labelled. This is further evidence suggesting an involvement of Alix in the events driving neuronal death.
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Affiliation(s)
- David Blum
- Laboratoire de Neurophysiologie, ULB Erasme, 808 route de Lennik, 1070 Brussels, Belgium.
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8
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Trioulier Y, Torch S, Blot B, Cristina N, Chatellard-Causse C, Verna JM, Sadoul R. Alix, a Protein Regulating Endosomal Trafficking, Is Involved in Neuronal Death. J Biol Chem 2004; 279:2046-52. [PMID: 14585841 DOI: 10.1074/jbc.m309243200] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [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: 11/06/2022] Open
Abstract
Alix/AIP1 is a cytoplasmic protein, which was first characterized as an interactor of ALG-2, a calcium-binding protein necessary for cell death. Alix has also recently been defined as a regulator of the endo-lysosomal system. Here we have used post-mitotic cerebellar neurons to test Alix function in caspase-dependent and -independent cell death. Indeed, these neurons survived when cultured in 25 mm potassium-containing medium but underwent apoptosis soon after the extracellular potassium was lowered to 5 mm. In agreement with other studies, we show that caspases are activated after K+ deprivation, but that inhibition of these proteases, using the pancaspase inhibitor boc-aspartyl(OMe)-fluoromethylketone, has no effect on cell survival. Transfection experiments demonstrated that Alix overexpression is sufficient to induce caspase activation, whereas overexpression of its C-terminal half, Alix-CT, blocks caspase activation and cell death after K+ deprivation. We also define a 12-amino acid PXY repeat of the C-terminal proline-rich domain necessary for binding ALG-2. Deletion of this domain in Alix or in Alix-CT abolished the effects of the overexpressed proteins on neuronal survival, demonstrating that the ALG-2-binding region is crucial for the death-modulating function of Alix. Overall, these findings define the Alix/ALG-2 complex as a regulator of cell death controlling both caspase-dependent and -independent pathways. They also suggest a molecular link between the endo-lysosomal system and the effectors of the cell death machinery.
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Affiliation(s)
- Yaël Trioulier
- Laboratoire Neurodégénérescence et Plasticité, INSERM-UJF, Pavillon de Neurologie, Hopital A. Michallon, 38043 Grenoble Cedex 9, France
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9
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Chatellard-Causse C, Blot B, Cristina N, Torch S, Missotten M, Sadoul R. Alix (ALG-2-interacting protein X), a protein involved in apoptosis, binds to endophilins and induces cytoplasmic vacuolization. J Biol Chem 2002; 277:29108-15. [PMID: 12034747 DOI: 10.1074/jbc.m204019200] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.5] [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: 11/06/2022] Open
Abstract
ALG-2-interacting protein X (Alix), also known as AIP1, is a cytoplasmic protein ubiquitously expressed and concentrated in phagosomes and exosomes. Alix may regulate apoptosis since it binds apoptosis-linked gene 2 (ALG-2), a Ca2+-binding protein necessary for cell death, and also overexpression of its C-terminal half (Alix-CT) blocks death induced by several stimuli. This part of Alix contains a long proline-rich domain containing several potential SH3-binding sites. Using Alix as bait in a yeast two-hybrid system to screen a mouse brain library, we have found that SH3p4, SH3p8, and SH3p13, collectively known as endophilins, bind to Alix. Co-immunoprecipitations and overlay experiments allowed us to demonstrate that endophilins bind to Alix-CT through an SH3/proline-rich domain interaction. We have narrowed the region of Alix interacting with endophilins down to 14 amino acids containing a PXRPPPP consensus sequence, also present in synaptojanin and germinal center kinase-like kinase, allowing their interaction to endophilins. We further show that overexpression of Alix-CT, which blocks cell death, leads to cytoplasmic vacuolization into tubulo-vesicular structures delineated by Alix-CT. This vacuolization phenomenon is greatly enhanced upon co-expression with endophilins and may be part of the protecting mechanism afforded by Alix-CT.
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Affiliation(s)
- Christine Chatellard-Causse
- Laboratoire Neurodégénérescence et Plasticité, INSERM-UJF (EMI 0108), Hopital A. Michallon, CHU, BP 217, 38043 Grenoble Cedex 9, France
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10
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11
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Blum D, Torch S, Lambeng N, Nissou M, Benabid AL, Sadoul R, Verna JM. Molecular pathways involved in the neurotoxicity of 6-OHDA, dopamine and MPTP: contribution to the apoptotic theory in Parkinson's disease. Prog Neurobiol 2001; 65:135-72. [PMID: 11403877 DOI: 10.1016/s0301-0082(01)00003-x] [Citation(s) in RCA: 881] [Impact Index Per Article: 38.3] [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: 12/21/2022]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder characterized by a preferential loss of the dopaminergic neurons of the substantia nigra pars compacta. Although the etiology of PD is unknown, major biochemical processes such as oxidative stress and mitochondrial inhibition are largely described. However, despite these findings, the actual therapeutics are essentially symptomatical and are not able to block the degenerative process. Recent histological studies performed on brains from PD patients suggest that nigral cell death could be apoptotic. However, since post-mortem studies do not allow precise determination of the sequence of events leading to this apoptotic cell death, the molecular pathways involved in this process have been essentially studied on experimental models reproducing the human disease. These latter are created by using neurotoxic compounds such as 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or dopamine (DA). Extensive study of these models have shown that they mimick, in vitro and in vivo, the histological and/or the biochemical characteristics of PD and thus help to define important cellular actors of cell death presumably critical for the nigral degeneration. This review reports recent data concerning the biochemical and molecular apoptotic mechanisms underlying the experimental models of PD and correlates them to the phenomena occurring in human disease.
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Affiliation(s)
- D Blum
- Unité Mixte INSERM/UJF E0108, Neurodégénérescence et plasticité, CHU Michallon, Pavillon de Neurologie, BP217, 38043 Cedex 9, Grenoble, France.
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12
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Abstract
The involvement of nuclear Factor-kappa B (NF-kappa B) transcription factor in PC12 cell death triggered by the dopaminergic neurotoxin 6-hydroxydopamine (6-OHDA) was investigated. Results show that oxidative stress generated by 6-OHDA activates NF-kappa B. When the NF-kappa B activation was inhibited by parthenolide, PC12 cell death induced by 6-OHDA was significantly increased, thus suggesting an involvement of this transcription factor in a protective mechanism against 6-OHDA toxicity. To further assess this hypothesis, we studied the involvement of NF-kappa B in the protective effect of two anti-apoptotic genes, bcl-2 and bfl-1. Although Bcl-2 and Bfl-1 expression normally protects PC12 cells from 6-OHDA, parthenolide strongly decreased the beneficial effects afforded by transgene expression. These results suggest: (1) that the transcription factor NF-kappa B is likely associated with the protection of catecholaminergic PC12 cells and (2) that the protective effects afforded by bcl-2 and bfl-1 expression may be dependent on NF-kappa activation.
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Affiliation(s)
- D Blum
- Laboratoire de Neurophysiologie, Département de Neurosciences, ULB-Erasme, 808 route de Lennik, CP601, 1070 Bruxelles, Belgium.
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13
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Abstract
6-hydroxydopamine (6-OHDA) is usually thought to cross cell membrane through dopamine uptake transporters, to inhibit mitochondrial respiration and to generate intracellular reactive oxygen species. In this study, we show that the anti-oxidants catalase, glutathione and N-acetyl-cysteine are able to reverse the toxic effects of 6-OHDA. These two latter compounds considerably slow down 6-OHDA oxidation in a cell free system suggesting a direct chemical interaction with the neurotoxin. Moreover, desipramine does not protect PC12 cells and 6-OHDA is also strongly toxic towards non-catecholaminergic C6 and NIH3T3 cells. These results thus suggest that 6-OHDA toxicity on PC12 cells mainly involves an extracellular process.
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Affiliation(s)
- D Blum
- ULB-Campus Erasme, Laboratory of Neurophysiology, Department of Neurosciences, 808 Rte de Lennik, CP601, 1070, Brussels, Belgium.
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14
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Abstract
Gene transfection and ectopic expression is a widely used method in experimental biology. In the present report, we would like to point out that this approach may, in certain circumstances, lead to a modification of the transfected cell phenotype. Indeed, we observed that after transfection of bcl-2 gene in the neuronal PC12 cell line some of the selected clones have lost their neuronal and catecholaminergic characteristics, i.e. TH expression and ability to grow neurites in response to NGF. Thus, the resistance of some PC12-Bcl-2 clones against neurotoxic insults may not necessarily reflect the potential benefit afforded by Bcl-2 expression. We therefore encouraged authors to verify cell phenotype after stable transfection to avoid misinterpretation of their results.
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Affiliation(s)
- D Blum
- NDP-LAPSEN, CHU Michallon, Pavillon de Neurologie, BP 217, 38043 Grenoble, France.
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15
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Tosic M, Torch S, Comte V, Dolivo M, Honegger P, Matthieu JM. Triiodothyronine has diverse and multiple stimulating effects on expression of the major myelin protein genes. J Neurochem 1992; 59:1770-7. [PMID: 1383426 DOI: 10.1111/j.1471-4159.1992.tb11009.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.1] [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: 12/26/2022]
Abstract
If the importance of triiodothyronine (T3) on brain development including myelinogenesis has long been recognized, its mechanism of action at the gene level is still not fully elucidated. We studied the effect of T3 on the expression of myelin protein genes in aggregating brain cell cultures. T3 increases the concentrations of mRNA transcribed from the following four myelin protein genes: myelin basic protein (Mbp), myelin-associated glycoprotein (Mag), proteolipid protein (Plp), and 2',3'-cyclic nucleotide 3'-phosphodiesterase (Cnp). T3 is not only a triggering signal for oligodendrocyte differentiation, but it has continuous stimulatory effects on myelin gene expression. Transcription in isolated nuclei experiments shows that T3 increases Mag and Cnp transcription rates. After inhibiting transcription with actinomycin D, we measured the half-lives of specific mRNAs. Our results show that T3 increases the stability of mRNA for myelin basic protein, and probably proteolipid protein. In vitro translation followed by myelin basic protein-specific immunoprecipitation showed a direct stimulatory effect of T3 on myelin basic protein mRNA translation. Moreover, this stimulation was higher when the mRNA was already stabilized in culture, indicating that stabilization is achieved through mRNA structural modifications. These results demonstrate the diverse and multiple mechanisms of T3 stimulation of myelin protein genes.
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Affiliation(s)
- M Tosic
- Laboratoire de Neurochimie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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16
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Barret L, Torch S, Usson Y, Gonthier B, Saxod R. A morphometric evaluation of the effects of trichloroethylene and dichloroacetylene on the rat mental nerve. Preliminary results. Neurosci Lett 1991; 131:141-44. [PMID: 1762688 DOI: 10.1016/0304-3940(91)90598-n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [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: 12/28/2022]
Abstract
Morphometric analysis was used to compare the effects of trichloroethylene (Tri) and dichloroacetylene (Dca) on the fibre parameters of the trigeminal nerve. Treated animals were clearly separated from controls according to a discriminant analysis. Furthermore, in the class of nerve fibres defined by a clustering analysis and corresponding to the largest fibres, myelin thickness was significantly decreased in the Dca group, but less so in the Tri group. In the group of the smallest fibres however, the myelin thickness was significantly increased by the treatments, but especially by Tri. Such a variability in the effects of Tri has already been demonstrated. Mechanisms for this are quite unclear although demyelination could be involved as already suggested. Our results thus show the ability of Tri and Dca to alter nerve parameters but probably with different modes of action depending on the size of the fibre.
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Affiliation(s)
- L Barret
- Laboratoire de Toxicologie, CHU de Grenoble, France
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17
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Usson Y, Torch S, Saxod R. Morphometry of human nerve biopsies by means of automated cytometry: assessment with reference to ultrastructural analysis. Anal Cell Pathol 1991; 3:91-102. [PMID: 2025607] [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: 12/29/2022] Open
Abstract
The morphometric analysis of myelinated fibres is a tool for diagnosis of neuropathies and for assessing nerve regeneration after reconstructive surgery. In order to obtain reliable information, sampling techniques should be avoided and the measurement of all the fibres within a nerve fascicle requiring the use of automated cytometry is necessary. We have developed a programme on the SAMBA cytological image analyser for the automated measurement of myelinated fibres. Different techniques of segmentation were tested and adaptive grey level thresholding gave the more reliable result. Accuracy and reproducibility were tested using a set of five human superficial peroneal nerve biopsies that were previously analysed by means of semi-automatic ultrastructural morphometry. A maximum difference of 9% in the number of fibres counted was obtained when comparing the automatic and the semi-automatic methods. In all cases the histograms of the morphometrical variables (fibre and axon diameters, myelin sheath thickness) were found to be identical to the reference histograms obtained by the semi-automatic method.
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Affiliation(s)
- Y Usson
- TIM3, USR B 690 CNRS, Equipe de Reconnaissance des formes et Microscopie Quantitative, CERMO, Grenoble, France
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18
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Abstract
In this paper we describe a program using the image analyzer SAMBA, which allows an automatic analysis of silver stained semithin nerve sections. The operator can interactively delimit the contour of the fascicle to be analysed by means of a digitizing tablet connected to the system which generates a mask of the region. Segmentation of the fibre images is conducted as a function of brightness threshold defined by the operator. Fibre clusters are automatically separated using morphological procedures like dilatation. Morphometric parameters such as the external and axonal diameters, myelin sheath thickness and circularity are measured. We are now testing this method on normal and pathological human superficial peroneal nerves. Preliminary results are promising and the development of adequate statistical analysis of morphometric data will provide us with a new tool for the diagnosis of peripheral neuropathies.
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Affiliation(s)
- S Torch
- Laboratoire de Biologie Animale, Equipe de Neurobiologie du Développement, Université Joseph Fourier, Grenoble, France
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19
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Torch S, Stoebner P, Usson Y, D'Aubigny GD, Saxod R. There is no simple adequate sampling scheme for estimating the myelinated fibre size distribution in human peripheral nerve: a statistical ultrastructural study. J Neurosci Methods 1989; 27:149-64. [PMID: 2709883 DOI: 10.1016/0165-0270(89)90098-8] [Citation(s) in RCA: 22] [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: 01/02/2023]
Abstract
Morphometric studies of peripheral nerves (PN) usually involve some sampling of the myelinated fibres (MF). In order to scrutinize the statistical properties of the sampling processes in common use and the reliability of the resulting estimates, a quantitative analysis of human superficial peroneal nerves from 8 different normal subjects was undertaken at the ultrastructural level, both in terms of MF spatial distribution and of their size distribution. This study used sampling rates involving more than 10% of the whole myelinated fibre population observed in each nerve fascicle. However, in nearly all the fascicles evaluated, the sampling fluctuations are so high that neither the number of axons nor their diameter distribution can be assessed with enough accuracy. A systematic study of the myelinated fibres shows that the spatial distribution of their size is not uniform. This marked heterogeneity in the MF size distribution imposes measurement of large enough samples (500 or 600 MFs usually represent about one-half or two-thirds of the whole MF population) in a way to secure a reliable enough estimate of the density and size distributions. However, the practical usefulness of sampling schemes requiring more than one-half of the whole MF population in a nerve fascicle, is questionable.
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Affiliation(s)
- S Torch
- Laboratoire de Biologie Animale, Unité Associée CNRS no 682, Université Joseph Fourier, Grenoble, France
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20
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Usson Y, Torch S, Drouet d'Aubigny G. A method for automatic classification of large and small myelinated fibre populations in peripheral nerves. J Neurosci Methods 1987; 20:237-48. [PMID: 3306173 DOI: 10.1016/0165-0270(87)90056-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The statistical analysis of morphometric data collected from biopsies of human superficial peroneal nerve is complicated by the heterogeneity of the population of myelinated fibres. In order to make separate statistical analyses of the subpopulations of large and small fibres we have developed a computer program (written in PASCAL) for their automatic separation. The method is based on a dynamic centres clustering algorithm and was applied to the multifactorial space defined by the principal component analysis of the morphometric variables: axonal diameter, myelin sheath thickness, circularity index and g-ratio. The classification technique was applied to measurements obtained from 5 control nerves, and to simulated data, and in each case it gave consistent Gaussian subpopulations with no need for the introduction of supplementary variables.
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21
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Saxod R, Torch S, Vila A, Laurent A, Stoebner P. The density of myelinated fibres is related to the fascicle diameter in human superficial peroneal nerve. Statistical study of 41 normal samples. J Neurol Sci 1985; 71:49-64. [PMID: 4087019 DOI: 10.1016/0022-510x(85)90036-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The density of myelinated fibres in the superficial peroneal nerve was studied in 41 samples from 24 control human subjects. Photographic montages of the whole nerve fascicle were made from semithin and ultrathin transverse sections and used for a statistical analysis of sampling procedures, range of variations and relations between density and other variables. The results indicate that the spatial distribution of myelinated fibres within a nerve is often non-uniform. Therefore, it was not possible to define a statistically valid sampling system. The study of relations between variables shows the lack of any correlation between density and age and a considerable variation in the density. In contrast, there is a strong positive linear correlation between the surface area of the nerve fascicle and its content of myelinated fibres. That is, the fibre density of a given normal nerve is related to its diameter and can be predicted within a narrow range of error. We propose the term "derived density" for this value, and its application as a tool in the diagnosis of peripheral neuropathies is now being studied.
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