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Grumelli C, Corradini I, Matteoli M, Verderio C. Intrinsic calcium dynamics control botulinum toxin A susceptibility in distinct neuronal populations. Cell Calcium 2010; 47:419-24. [DOI: 10.1016/j.ceca.2010.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 02/23/2010] [Accepted: 03/01/2010] [Indexed: 11/25/2022]
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Grumelli C, Berghuis P, Pozzi D, Caleo M, Antonucci F, Bonanno G, Carmignoto G, Dobszay MB, Harkany T, Matteoli M, Verderio C. Calpain activity contributes to the control of SNAP-25 levels in neurons. Mol Cell Neurosci 2008; 39:314-23. [PMID: 18721885 DOI: 10.1016/j.mcn.2008.07.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 07/04/2008] [Accepted: 07/08/2008] [Indexed: 01/20/2023] Open
Abstract
Calpains are a family of calcium-dependent proteases with abundant expression in the CNS, and potent in cleaving some synaptic components. Assessment of calpain activity by its fluorescent substrate, Boc-Leu-Met-CMAC, revealed that cultured neurons display a significant level of constitutive enzyme activity. Notably, calpain activity differs in distinct neuronal populations, with a significantly higher level of activity in GABAergic cells. Using selectively-enriched cultures of fast-spiking GABAergic interneurons, we show that calpain activity partially contributes to the post-translational down regulation of SNAP-25, a calpain substrate, in differentiated GABA cells. In addition, we demonstrate that SNAP-25 is cleaved by calpain in response to acute seizures induced by intraperitoneal kainate injection in vivo. These data indicate that calpains in neurons are active even at physiological calcium concentrations and that different levels of calpain activation in selected neuron subtypes may contribute to the pattern of synaptic protein expression.
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Affiliation(s)
- Carlotta Grumelli
- Dipartimento di Farmacologia Medica, Istituto CNR di Neuroscienze, Universita' di Milano, Italy
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Pozzi D, Condliffe S, Bozzi Y, Chikhladze M, Grumelli C, Proux-Gillardeaux V, Takahashi M, Franceschetti S, Verderio C, Matteoli M. Activity-dependent phosphorylation of Ser187 is required for SNAP-25-negative modulation of neuronal voltage-gated calcium channels. Proc Natl Acad Sci U S A 2008; 105:323-8. [PMID: 18162553 PMCID: PMC2224210 DOI: 10.1073/pnas.0706211105] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Indexed: 11/18/2022] Open
Abstract
Synaptosomal-associated protein of 25 kDa (SNAP-25) is a SNARE protein that regulates neurotransmission by the formation of a complex with syntaxin 1 and synaptobrevin/VAMP2. SNAP-25 also reduces neuronal calcium responses to stimuli, but neither the functional relevance nor the molecular mechanisms of this modulation have been clarified. In this study, we demonstrate that hippocampal slices from Snap25(+/-) mice display a significantly larger facilitation and that higher calcium peaks are reached after depolarization by Snap25(-/-) and Snap25(+/-) cultured neurons compared with wild type. We also show that SNAP-25b modulates calcium dynamics by inhibiting voltage-gated calcium channels (VGCCs) and that PKC phosphorylation of SNAP-25 at ser187 is essential for this process, as indicated by the use of phosphomimetic (S187E) or nonphosphorylated (S187A) mutants. Neuronal activity is the trigger that induces the transient phosphorylation of SNAP-25 at ser187. Indeed, enhancement of network activity increases the levels of phosphorylated SNAP-25, whereas network inhibition reduces the extent of protein phosphorylation. A transient peak of SNAP-25 phosphorylation also is detectable in rat hippocampus in vivo after i.p. injection with kainate to induce seizures. These findings demonstrate that differences in the expression levels of SNAP-25 impact on calcium dynamics and neuronal plasticity, and that SNAP-25 phosphorylation, by promoting inhibition of VGCCs, may mediate a negative feedback modulation of neuronal activity during intense activation.
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Affiliation(s)
- Davide Pozzi
- *Department of Medical Pharmacology and Consiglio Nazionale delle Ricerche–Institute of Neuroscience, University of Milano, Via Vanvitelli 32, 20129 Milan, Italy
- Italian Institute of Technology, Via Morego 30, 16163 Genoa, Italy
| | - Steven Condliffe
- *Department of Medical Pharmacology and Consiglio Nazionale delle Ricerche–Institute of Neuroscience, University of Milano, Via Vanvitelli 32, 20129 Milan, Italy
| | - Yuri Bozzi
- Consiglio Nazionale delle Ricerche Institute of Neuroscience, Via G. Moruzzi 1, 56100 Pisa, Italy
| | - Maia Chikhladze
- Istituto Neurologico C. Besta, Via Celoria 11, 20133 Milan, Italy
| | - Carlotta Grumelli
- *Department of Medical Pharmacology and Consiglio Nazionale delle Ricerche–Institute of Neuroscience, University of Milano, Via Vanvitelli 32, 20129 Milan, Italy
| | | | - Masami Takahashi
- Department of Biochemistry, Kitasato University School of Medicine, Kanagawa 228-8555, Japan
| | | | - Claudia Verderio
- *Department of Medical Pharmacology and Consiglio Nazionale delle Ricerche–Institute of Neuroscience, University of Milano, Via Vanvitelli 32, 20129 Milan, Italy
| | - Michela Matteoli
- *Department of Medical Pharmacology and Consiglio Nazionale delle Ricerche–Institute of Neuroscience, University of Milano, Via Vanvitelli 32, 20129 Milan, Italy
- **Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Don C. Gnocchi, 20129 Milan, Italy; and
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Verderio C, Grumelli C, Raiteri L, Coco S, Paluzzi S, Caccin P, Rossetto O, Bonanno G, Montecucco C, Matteoli M. Traffic of botulinum toxins A and E in excitatory and inhibitory neurons. Traffic 2007; 8:142-53. [PMID: 17241445 DOI: 10.1111/j.1600-0854.2006.00520.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Botulinum neurotoxins (BoNTs), proteases specific for the SNARE proteins, are used to study the molecular machinery supporting exocytosis and are used to treat human diseases characterized by cholinergic hyperactivity. The recent extension of the use of BoNTs to central nervous system (CNS) pathologies prompted the study of their traffic in central neurons. We used fluorescent BoNT/A and BoNT/E to study the penetration, the translocation and the catalytic action of these toxins in excitatory and inhibitory neurons. We show that BoNT/A and BoNT/E, besides preferentially inhibiting synaptic vesicle recycling at glutamatergic relative to Gamma-aminobutyric acid (GABA)-ergic neurons, are more efficient in impairing the release of excitatory than inhibitory neurotransmitter from brain synaptosomes. This differential effect does not result from a defective penetration of the toxin in line with the presence of the BoNT/A receptor, synaptic vesicle protein 2 (SV2), in both types of neurons. Interestingly, exogenous expression of SNAP-25 in GABAergic neurons confers sensitivity to BoNT/A. These results indicate that the expression of the toxin substrate, and not the toxin penetration, most likely accounts for the distinct effects of the two neurotoxins at the two types of terminals and support the use of BoNTs for the therapy of CNS diseases caused by the altered activity of selected neuronal populations.
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Affiliation(s)
- Claudia Verderio
- Department of Medical Pharmacology, University of Milano, Via Vanvitelli 32, 20129 Milano, Italy
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Verderio C, Rossetto O, Grumelli C, Frassoni C, Montecucco C, Matteoli M. Entering neurons: botulinum toxins and synaptic vesicle recycling. EMBO Rep 2006; 7:995-9. [PMID: 17016457 PMCID: PMC1618376 DOI: 10.1038/sj.embor.7400796] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Accepted: 07/27/2006] [Indexed: 11/08/2022] Open
Abstract
Botulinum toxins are metalloproteases that act inside nerve terminals and block neurotransmitter release through their cleavage of components of the exocytosis machinery. These toxins are used to treat human diseases that are characterized by hyperfunction of cholinergic terminals. Recently, evidence has accumulated that gangliosides and synaptic vesicle proteins cooperate to mediate toxin binding to the presynaptic terminal. The differential distribution of synaptic vesicle protein receptors, gangliosides and toxin substrates in distinct neuronal populations opens up the possibility of using different serotypes of botulinum toxins for the treatment of central nervous system diseases caused by altered activity of selected neuronal populations.
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Affiliation(s)
- Claudia Verderio
- Department of Pharmacology and CNR Institute of Neuroscience, Center of Excellence for Neurodegenerative Diseases, University of Milano, Via Vanvitelli 32, 20129 Milano, Italy
| | - Ornella Rossetto
- Dipartimento di Scienze Biomediche Sperimentali, Università di Padova, Via G. Colombo 3, 35121 Padova, Italy
| | - Carlotta Grumelli
- Department of Pharmacology and CNR Institute of Neuroscience, Center of Excellence for Neurodegenerative Diseases, University of Milano, Via Vanvitelli 32, 20129 Milano, Italy
| | | | - Cesare Montecucco
- Dipartimento di Scienze Biomediche Sperimentali, Università di Padova, Via G. Colombo 3, 35121 Padova, Italy
| | - Michela Matteoli
- Department of Pharmacology and CNR Institute of Neuroscience, Center of Excellence for Neurodegenerative Diseases, University of Milano, Via Vanvitelli 32, 20129 Milano, Italy
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Grumelli C, Verderio C, Pozzi D, Rossetto O, Montecucco C, Matteoli M. Internalization and Mechanism of Action of Clostridial Toxins in Neurons. Neurotoxicology 2005; 26:761-7. [PMID: 15925409 DOI: 10.1016/j.neuro.2004.12.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Accepted: 12/21/2004] [Indexed: 10/25/2022]
Abstract
Botulinum toxins are metalloproteases that act inside nerve terminals and block neurotransmitter release via their activity directed specifically on SNARE proteins. This review summarizes data on botulinum toxin modes of binding, sites of action, and biochemical activities. Their use in cell biology and neuroscience is considered, as well as their therapeutic utilization in human diseases characterized by hyperfunction of cholinergic terminals.
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Affiliation(s)
- Carlotta Grumelli
- Department of Medical Pharmacology and CNR Institute of Neuroscience, Center of Excellence for Neurodegenerative Diseases, University of Milano, Via Vanvitelli 32, 20129 Milano, Italy
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Frassoni C, Inverardi F, Coco S, Ortino B, Grumelli C, Pozzi D, Verderio C, Matteoli M. Analysis of SNAP-25 immunoreactivity in hippocampal inhibitory neurons during development in culture and in situ. Neuroscience 2005; 131:813-23. [PMID: 15749336 DOI: 10.1016/j.neuroscience.2004.11.042] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2004] [Indexed: 11/23/2022]
Abstract
Synaptosomal associated protein of 25 kDa (SNAP-25) is a component of the soluble N-ethylmaleimide-sensitive fusion protein (NSF) attachment protein receptor (SNARE) complex which plays a central role in synaptic vesicle exocytosis. We have previously demonstrated that adult rat hippocampal GABAergic synapses, both in culture and in brain, are virtually devoid of SNAP-25 immunoreactivity and are less sensitive to the action of botulinum toxin type A, which cleaves this SNARE protein [Neuron 41 (2004) 599]. In the present study, we extend our findings to the adult mouse hippocampus and we also provide demonstration that hippocampal inhibitory synapses lacking SNAP-25 labeling belong to parvalbumin-, calretinin- and cholecystokinin-positive interneurons. A partial colocalization between SNAP-25 and glutamic acid decarboxylase is instead detectable in developing mouse hippocampus at P0 and, at a lesser extent, at P5. In rat embryonic hippocampal cultures at early developmental stages, SNAP-25 immunoreactivity is detectable in a percentage of GABAergic neurons, which progressively reduces with time in culture. Consistent with the presence of the substrate, botulinum toxin type A is partially effective in inhibiting synaptic vesicle recycling in immature GABAergic neurons. Since SNAP-25, beside its role as a SNARE protein, is involved in additional processes, such as neurite outgrowth and regulation of calcium dynamics, the presence of higher levels of the protein at specific stages of neuronal differentiation may have implications for the construction and for the functional properties of brain circuits.
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Affiliation(s)
- C Frassoni
- Department of Medical Pharmacology, CNR Institute of Neuroscience, University of Milano, Center of Excellence on Neurodegenerative Diseases, Milano, Italy
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