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Ding D, Qi W, Jiang H, Salvi R. Excitotoxic damage to auditory nerve afferents and spiral ganglion neurons is correlated with developmental upregulation of AMPA and KA receptors. Hear Res 2021; 411:108358. [PMID: 34607211 DOI: 10.1016/j.heares.2021.108358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/29/2021] [Accepted: 09/21/2021] [Indexed: 12/31/2022]
Abstract
Excess release of glutamate at the inner hair cell-type I auditory nerve synapse results in excitotoxicity characterized by rapid swelling and disintegration of the afferent synapses, but in some cases, the damage expands to the spiral ganglion soma. Cochlear excitotoxic damage is largely mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) and kainate receptor (KAR) and potentially N-methyl-D-aspartate receptors (NMDAR). Because these receptors are developmentally regulated, the pattern of excitotoxic damage could change during development. To test this hypothesis, we compared AMPAR, NMDAR and KAR immunolabeling and excitotoxic damage patterns in rat postnatal day 3 (P3) and adult cochlear cultures. At P3, AMPAR and KAR immunolabeling, but not NMDAR, was abundantly expressed on peripheral nerve terminals adjacent to IHCs. In contrast, AMPAR, KAR and NMDAR immunolabeling was minimal or undetectable on the SGN soma. In adult rats, however, AMPAR, KAR and NMDAR immunolabeling occurred on both peripheral nerve terminals near IHCs as well as the soma of SGNs. High doses of Glu and KA only damaged peripheral nerve terminals near IHCs, but not SGNs, at P3, consistent with selective expression of AMPAR and KAR expression on the terminals. However, in adults, Glu and KA damaged both peripheral nerve terminals near IHCs and SGNs both of which expressed AMPAR and KAR. These results indicate that cochlear excitotoxic damage is closely correlated with structures that express AMPAR and KAR.
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Affiliation(s)
- Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, Buffalo, NY 14214, USA
| | - Weidong Qi
- Department of Otolaryngology, Huashan Hospital Fudan University, Shanghai 200040, China
| | - Haiyan Jiang
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, Buffalo, NY 14214, USA
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, 137 Cary Hall, Buffalo, NY 14214, USA.
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Cao C, Rioult-Pedotti MS, Migani P, Yu CJ, Tiwari R, Parang K, Spaller MR, Goebel DJ, Marshall J. Impairment of TrkB-PSD-95 signaling in Angelman syndrome. PLoS Biol 2013; 11:e1001478. [PMID: 23424281 PMCID: PMC3570550 DOI: 10.1371/journal.pbio.1001478] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 01/02/2013] [Indexed: 11/19/2022] Open
Abstract
Brain-derived neurotrophic factor signaling is defective in Angelman syndrome and can be rescued by disruption of Arc/PSD95 binding. Angelman syndrome (AS) is a neurodevelopment disorder characterized by severe cognitive impairment and a high rate of autism. AS is caused by disrupted neuronal expression of the maternally inherited Ube3A ubiquitin protein ligase, required for the proteasomal degradation of proteins implicated in synaptic plasticity, such as the activity-regulated cytoskeletal-associated protein (Arc/Arg3.1). Mice deficient in maternal Ube3A express elevated levels of Arc in response to synaptic activity, which coincides with severely impaired long-term potentiation (LTP) in the hippocampus and deficits in learning behaviors. In this study, we sought to test whether elevated levels of Arc interfere with brain-derived neurotrophic factor (BDNF) TrkB receptor signaling, which is known to be essential for both the induction and maintenance of LTP. We report that TrkB signaling in the AS mouse is defective, and show that reduction of Arc expression to control levels rescues the signaling deficits. Moreover, the association of the postsynaptic density protein PSD-95 with TrkB is critical for intact BDNF signaling, and elevated levels of Arc were found to impede PSD-95/TrkB association. In Ube3A deficient mice, the BDNF-induced recruitment of PSD-95, as well as PLCγ and Grb2-associated binder 1 (Gab1) with TrkB receptors was attenuated, resulting in reduced activation of PLCγ-α-calcium/calmodulin-dependent protein kinase II (CaMKII) and PI3K-Akt, but leaving the extracellular signal-regulated kinase (Erk) pathway intact. A bridged cyclic peptide (CN2097), shown by nuclear magnetic resonance (NMR) studies to uniquely bind the PDZ1 domain of PSD-95 with high affinity, decreased the interaction of Arc with PSD-95 to restore BDNF-induced TrkB/PSD-95 complex formation, signaling, and facilitate the induction of LTP in AS mice. We propose that the failure of TrkB receptor signaling at synapses in AS is directly linked to elevated levels of Arc associated with PSD-95 and PSD-95 PDZ-ligands may represent a promising approach to reverse cognitive dysfunction. Angelman syndrome (AS) is a debilitating neurological disorder caused by a dysfunctional Ube3A gene. Most children with AS exhibit developmental delay, movement disorders, speech impairment, and often autistic features. The Ube3A enzyme normally regulates the degradation of the synaptic protein Arc, and in its absence the resulting elevated levels of Arc weaken synaptic contacts, making it difficult to generate long-term potentiation (LTP) and to process and store memory. In this study, we show that increased levels of Arc disrupt brain-derived neurotrophic factor (BDNF) signaling through the TrkB receptor (which is important for both the induction and maintenance of LTP). We find that the association of the postsynaptic density protein PSD-95 with TrkB is critical for intact BDNF signaling, and that the high levels of Arc in AS interfere with BDNF-induced recruitment of postsynaptic density protein-95 (PSD-95) and other effectors to TrkB. By disrupting the interaction between Arc and PSD-95 with the novel cyclic peptidomimetic compound CN2097, we were able to restore BDNF signaling and improve the induction of LTP in a mouse model of AS. We propose that the disruption of TrkB receptor signaling at synapses contributes to the cognitive dysfunction that occurs in Angelman syndrome.
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Affiliation(s)
- Cong Cao
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, Rhode Island, United States of America
- Institute of Neuroscience, The Second Affiliated Hospital of Soochow University, Soochow University, Suzhou, China
| | - Mengia S. Rioult-Pedotti
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, Rhode Island, United States of America
| | - Paolo Migani
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, Italy
| | - Crystal J. Yu
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, Rhode Island, United States of America
| | - Rakesh Tiwari
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island, United States of America
| | - Keykavous Parang
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island, United States of America
| | - Mark R. Spaller
- Norris Cotton Cancer Center and Department of Pharmacology and Toxicology, Dartmouth Medical School, Lebanon, New Hampshire, United States of America
| | - Dennis J. Goebel
- Department of Anatomy and Cell Biology, Wayne State University, Detroit, Michigan, United States of America
- * E-mail: (DJG); (JM)
| | - John Marshall
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, Rhode Island, United States of America
- * E-mail: (DJG); (JM)
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Chen J, Herrup K. Selective vulnerability of neurons in primary cultures and in neurodegenerative diseases. Rev Neurosci 2009; 19:317-26. [PMID: 19145987 DOI: 10.1515/revneuro.2008.19.4-5.317] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Primary neuronal cultures are commonly used to dissect the molecular and cellular mechanisms that underlie human brain diseases. Neurons dissociated from an embryonic brain and grown in culture dishes are almost by definition different from those residing inside a living brain. Not only are the individual cells stripped of their normal chemical and physical contacts, but the cellular composition of the cultures (the ratio of cell types) can be affected by many intrinsic and extrinsic factors, including brain region, neuronal birthday, gender, genetic background and in vitro age. Changes in any of these factors may have a strong impact on the outcome of the experiment. In a recent study, Romito-DiGiacomo et al. /54/ demonstrated that when neurons were harvested from murine embryonic cortex, the typical protocol favored cells that were just finishing cell division at the time of harvest. By taking advantage of the fact that the date of the final cell division (birthday) of a neuron correlates with its final position in the cortical plate they were able to assay deeper layer neurons (layers V-VI) separately from the more superficial layers (layers II-III). They reported that while the superficial cells were sensitive to the toxic effect of beta-amyloid, the deeper layer neurons were virtually resistant to death in its presence. The findings recapitulate selective vulnerability in the neocortex of Alzheimer's disease. This is a beautiful example of how to turn the apparent weakness of primary cultures into strength through experimental design and data interpretation. Selective vulnerability is a common feature of neurodegenerative disease, thus it is critical to use the right primary culture. Do you know what is in your culture?
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Affiliation(s)
- Jianmin Chen
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ 08901, USA
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Lee HY, Greene LA, Mason CA, Manzini MC. Isolation and culture of post-natal mouse cerebellar granule neuron progenitor cells and neurons. J Vis Exp 2009:990. [PMID: 19229177 PMCID: PMC2781826 DOI: 10.3791/990] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The cerebellar cortex is a well described structure that provides unique opportunities for studying neuronal properties and development1,2. Of the cerebellar neuronal types (granule cells, Purkinje cells and inhibitory interneurons), granule neurons are by far the most numerous and are the most abundant type of neurons in the mammalian brain. In rodents, cerebellar granule neurons are generated during the first two post-natal weeks from progenitor cells in the outermost layer of the cerebellar cortex, the external granule layer (EGL). The protocol presented here describes techniques to enrich and culture granule neurons and their progenitor cells from post-natal mouse cerebellum. We will describe procedures to obtain cultures of increasing purity3,4, which can be used to study the differentiation of proliferating progenitor cells into granule neurons5,6. Once the progenitor cells differentiate, the cultures also provide a homogenous population of granule neurons for experimental manipulation and characterization of phenomena such as synaptogenesis, glutamate receptor function7, interaction with other purified cerebellar cells8,9 or cell death7.
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Affiliation(s)
- Hae Young Lee
- Department of Genetics and Development, Columbia University, USA
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