Calcium-Dependent Hyperexcitability in Human Stem Cell–Derived Rett Syndrome Neuronal Networks
Background: Mutations in MECP2 predominantly cause Rett syndrome and can be modeled in vitro using human stem cell–derived neurons. Patients with Rett syndrome have signs of cortical hyperexcitability, such as seizures. Human stem cell–derived MECP2 null excitatory neurons have smaller soma size and...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2024-03-01
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| Series: | Biological Psychiatry Global Open Science |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S266717432400003X |
| _version_ | 1827344791042523136 |
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| author | Kartik S. Pradeepan Fraser P. McCready Wei Wei Milad Khaki Wenbo Zhang Michael W. Salter James Ellis Julio Martinez-Trujillo |
| author_facet | Kartik S. Pradeepan Fraser P. McCready Wei Wei Milad Khaki Wenbo Zhang Michael W. Salter James Ellis Julio Martinez-Trujillo |
| author_sort | Kartik S. Pradeepan |
| collection | DOAJ |
| description | Background: Mutations in MECP2 predominantly cause Rett syndrome and can be modeled in vitro using human stem cell–derived neurons. Patients with Rett syndrome have signs of cortical hyperexcitability, such as seizures. Human stem cell–derived MECP2 null excitatory neurons have smaller soma size and reduced synaptic connectivity but are also hyperexcitable due to higher input resistance. Paradoxically, networks of MECP2 null neurons show a decrease in the frequency of network bursts consistent with a hypoconnectivity phenotype. Here, we examine this issue. Methods: We reanalyzed multielectrode array data from 3 isogenic MECP2 cell line pairs recorded over 6 weeks (n = 144). We used a custom burst detection algorithm to analyze network events and isolated a phenomenon that we termed reverberating super bursts (RSBs). To probe potential mechanisms of RSBs, we conducted pharmacological manipulations using bicuculline, EGTA-AM, and DMSO on 1 cell line (n = 34). Results: RSBs, often misidentified as single long-duration bursts, consisted of a large-amplitude initial burst followed by several high-frequency, low-amplitude minibursts. Our analysis revealed that MECP2 null networks exhibited increased frequency of RSBs, which produced increased bursts compared with isogenic controls. Bicuculline or DMSO treatment did not affect RSBs. EGTA-AM selectively eliminated RSBs and rescued network burst dynamics. Conclusions: During early development, MECP2 null neurons are hyperexcitable and produce hyperexcitable networks. This may predispose them to the emergence of hypersynchronic states that potentially translate into seizures. Network hyperexcitability depends on asynchronous neurotransmitter release that is likely driven by presynaptic Ca2+ and can be rescued by EGTA-AM to restore typical network dynamics. |
| first_indexed | 2024-03-07T22:53:37Z |
| format | Article |
| id | doaj.art-bf64c74f1669454c9420b1a4508cfb26 |
| institution | Directory Open Access Journal |
| issn | 2667-1743 |
| language | English |
| last_indexed | 2024-03-07T22:53:37Z |
| publishDate | 2024-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Biological Psychiatry Global Open Science |
| spelling | doaj.art-bf64c74f1669454c9420b1a4508cfb262024-02-23T05:00:58ZengElsevierBiological Psychiatry Global Open Science2667-17432024-03-0142100290Calcium-Dependent Hyperexcitability in Human Stem Cell–Derived Rett Syndrome Neuronal NetworksKartik S. Pradeepan0Fraser P. McCready1Wei Wei2Milad Khaki3Wenbo Zhang4Michael W. Salter5James Ellis6Julio Martinez-Trujillo7Graduate Program in Neuroscience, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada; Robarts Research Institute, Western University, London, Ontario, CanadaDepartment of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada; Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, CanadaDevelopmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, CanadaRobarts Research Institute, Western University, London, Ontario, CanadaNeuroscience & Mental Health, The Hospital for Sick Children, Toronto, Ontario, CanadaNeuroscience & Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Physiology, University of Toronto, Toronto, Ontario, CanadaDepartment of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada; Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada; Address correspondence to James Ellis, Ph.D.Graduate Program in Neuroscience, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada; Robarts Research Institute, Western University, London, Ontario, Canada; Western Institute for Neuroscience, Western University, London, Ontario, Canada; Department of Physiology and Pharmacology, and Psychiatry, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada; Department of Psychiatry, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada; Julio Martinez-Trujillo, M.D., Ph.D.Background: Mutations in MECP2 predominantly cause Rett syndrome and can be modeled in vitro using human stem cell–derived neurons. Patients with Rett syndrome have signs of cortical hyperexcitability, such as seizures. Human stem cell–derived MECP2 null excitatory neurons have smaller soma size and reduced synaptic connectivity but are also hyperexcitable due to higher input resistance. Paradoxically, networks of MECP2 null neurons show a decrease in the frequency of network bursts consistent with a hypoconnectivity phenotype. Here, we examine this issue. Methods: We reanalyzed multielectrode array data from 3 isogenic MECP2 cell line pairs recorded over 6 weeks (n = 144). We used a custom burst detection algorithm to analyze network events and isolated a phenomenon that we termed reverberating super bursts (RSBs). To probe potential mechanisms of RSBs, we conducted pharmacological manipulations using bicuculline, EGTA-AM, and DMSO on 1 cell line (n = 34). Results: RSBs, often misidentified as single long-duration bursts, consisted of a large-amplitude initial burst followed by several high-frequency, low-amplitude minibursts. Our analysis revealed that MECP2 null networks exhibited increased frequency of RSBs, which produced increased bursts compared with isogenic controls. Bicuculline or DMSO treatment did not affect RSBs. EGTA-AM selectively eliminated RSBs and rescued network burst dynamics. Conclusions: During early development, MECP2 null neurons are hyperexcitable and produce hyperexcitable networks. This may predispose them to the emergence of hypersynchronic states that potentially translate into seizures. Network hyperexcitability depends on asynchronous neurotransmitter release that is likely driven by presynaptic Ca2+ and can be rescued by EGTA-AM to restore typical network dynamics.http://www.sciencedirect.com/science/article/pii/S266717432400003XBurst detectionHuman stem cell-derived neuronsMultielectrode arrayRett syndromeReverberations |
| spellingShingle | Kartik S. Pradeepan Fraser P. McCready Wei Wei Milad Khaki Wenbo Zhang Michael W. Salter James Ellis Julio Martinez-Trujillo Calcium-Dependent Hyperexcitability in Human Stem Cell–Derived Rett Syndrome Neuronal Networks Biological Psychiatry Global Open Science Burst detection Human stem cell-derived neurons Multielectrode array Rett syndrome Reverberations |
| title | Calcium-Dependent Hyperexcitability in Human Stem Cell–Derived Rett Syndrome Neuronal Networks |
| title_full | Calcium-Dependent Hyperexcitability in Human Stem Cell–Derived Rett Syndrome Neuronal Networks |
| title_fullStr | Calcium-Dependent Hyperexcitability in Human Stem Cell–Derived Rett Syndrome Neuronal Networks |
| title_full_unstemmed | Calcium-Dependent Hyperexcitability in Human Stem Cell–Derived Rett Syndrome Neuronal Networks |
| title_short | Calcium-Dependent Hyperexcitability in Human Stem Cell–Derived Rett Syndrome Neuronal Networks |
| title_sort | calcium dependent hyperexcitability in human stem cell derived rett syndrome neuronal networks |
| topic | Burst detection Human stem cell-derived neurons Multielectrode array Rett syndrome Reverberations |
| url | http://www.sciencedirect.com/science/article/pii/S266717432400003X |
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