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Abstract
Within the past decade, multiple lines of evidence have converged to identify a critical role for activity-regulated myelination in tuning the function of neural networks. In this Review, we provide an overview of accumulating evidence that activity-regulated myelination is required for brain adaptation and learning across multiple domains. We then discuss dysregulation of activity-dependent myelination in the context of neurological disease, a novel frontier with the potential to uncover new mechanisms of disease pathogenesis and to develop new therapeutic strategies. Alterations in myelination and neural network function can result from deficient myelin plasticity that impairs neurological function or from maladaptive myelination, in which intact activity-dependent myelination contributes to the disease process by promoting pathological patterns of neuronal activity. These emerging mechanisms suggest new avenues for therapeutic intervention that could more fully address the complex interactions between neurons and oligodendroglia.
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Knowles JK, Xu H, Soane C, Batra A, Saucedo T, Frost E, Tam LT, Fraga D, Ni L, Villar K, Talmi S, Huguenard JR, Monje M. Maladaptive myelination promotes generalized epilepsy progression. Nat Neurosci 2022; 25:596-606. [PMID: 35501379 PMCID: PMC9076538 DOI: 10.1038/s41593-022-01052-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 03/14/2022] [Indexed: 12/18/2022]
Abstract
Activity-dependent myelination can fine-tune neural network dynamics. Conversely, aberrant neuronal activity, as occurs in disorders of recurrent seizures (epilepsy), could promote maladaptive myelination, contributing to pathogenesis. In this study, we tested the hypothesis that activity-dependent myelination resulting from absence seizures, which manifest as frequent behavioral arrests with generalized electroencephalography (EEG) spike-wave discharges, promote thalamocortical network hypersynchrony and contribute to epilepsy progression. We found increased oligodendrogenesis and myelination specifically within the seizure network in two models of generalized epilepsy with absence seizures (Wag/Rij rats and Scn8a+/mut mice), evident only after epilepsy onset. Aberrant myelination was prevented by pharmacological seizure inhibition in Wag/Rij rats. Blocking activity-dependent myelination decreased seizure burden over time and reduced ictal synchrony as assessed by EEG coherence. These findings indicate that activity-dependent myelination driven by absence seizures contributes to epilepsy progression; maladaptive myelination may be pathogenic in some forms of epilepsy and other neurological diseases.
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Affiliation(s)
- Juliet K Knowles
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
| | - Haojun Xu
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.,Ph.D. Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Japan
| | - Caroline Soane
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Ankita Batra
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Tristan Saucedo
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Eleanor Frost
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Lydia T Tam
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Danielle Fraga
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Lijun Ni
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Katlin Villar
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Sydney Talmi
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - John R Huguenard
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
| | - Michelle Monje
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA. .,Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
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