Corticostriatal maldevelopment in the R6/2 mouse model of juvenile Huntington's disease

There is a growing consensus that brain development in Huntington's disease (HD) is abnormal, leading to the idea that HD is not only a neurodegenerative but also a neurodevelopmental disorder. Indeed, structural and functional abnormalities have been observed during brain development in both h...

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Main Authors: Carlos Cepeda, Sandra M. Holley, Joshua Barry, Katerina D. Oikonomou, Vannah-Wila Yazon, Allison Peng, Deneen Argueta, Michael S. Levine
Format: Article
Language:English
Published: Elsevier 2025-01-01
Series:Neurobiology of Disease
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Online Access:http://www.sciencedirect.com/science/article/pii/S0969996124003541
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author Carlos Cepeda
Sandra M. Holley
Joshua Barry
Katerina D. Oikonomou
Vannah-Wila Yazon
Allison Peng
Deneen Argueta
Michael S. Levine
author_facet Carlos Cepeda
Sandra M. Holley
Joshua Barry
Katerina D. Oikonomou
Vannah-Wila Yazon
Allison Peng
Deneen Argueta
Michael S. Levine
author_sort Carlos Cepeda
collection DOAJ
description There is a growing consensus that brain development in Huntington's disease (HD) is abnormal, leading to the idea that HD is not only a neurodegenerative but also a neurodevelopmental disorder. Indeed, structural and functional abnormalities have been observed during brain development in both humans and animal models of HD. However, a concurrent study of cortical and striatal development in a genetic model of HD is still lacking. Here we report significant alterations of corticostriatal development in the R6/2 mouse model of juvenile HD. We examined wildtype (WT) and R6/2 mice at postnatal (P) days 7, 14, and 21. Morphological examination demonstrated early structural and cellular alterations reminiscent of malformations of cortical development, and ex vivo electrophysiological recordings of cortical pyramidal neurons (CPNs) demonstrated significant age- and genotype-dependent changes of intrinsic membrane and synaptic properties. In general, R6/2 CPNs had reduced cell membrane capacitance and increased input resistance (P7 and P14), along with reduced frequency of spontaneous excitatory and inhibitory synaptic events during early development (P7), suggesting delayed cortical maturation. This was confirmed by increased occurrence of GABAA receptor-mediated giant depolarizing potentials at P7. At P14, the rheobase of CPNs was significantly reduced, along with increased excitability. Altered membrane and synaptic properties of R6/2 CPNs recovered progressively, and by P21 they were similar to WT CPNs. In striatal medium-sized spiny neurons (MSNs), a different picture emerged. Intrinsic membrane properties were relatively normal throughout development, except for a transient increase in membrane capacitance at P14. The first alterations in MSNs synaptic activity were observed at P14 and consisted of significant deficits in GABAergic inputs, however, these also were normalized by P21. In contrast, excitatory inputs began to decrease at this age. We conclude that the developing HD brain is capable of compensating for early developmental abnormalities and that cortical alterations precede and are a main contributor of striatal changes. Addressing cortical maldevelopment could help prevent or delay disease manifestations.
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spelling doaj-art-f3ac089decaf4e6d877173f479aa7d0f2025-01-07T04:17:05ZengElsevierNeurobiology of Disease1095-953X2025-01-01204106752Corticostriatal maldevelopment in the R6/2 mouse model of juvenile Huntington's diseaseCarlos Cepeda0Sandra M. Holley1Joshua Barry2Katerina D. Oikonomou3Vannah-Wila Yazon4Allison Peng5Deneen Argueta6Michael S. Levine7Corresponding author at: IDDRC, Semel Institute for Neuroscience, Room 58-258, UCLA, David Geffen School of Medicine, 760 Westwood Plaza, Los Angeles, CA 90024-1759, USA.; IDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USAIDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USAIDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USAIDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USAIDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USAIDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USAIDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USAIDDRC, Jane and Terry Semel Institute for Neuroscience & Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USAThere is a growing consensus that brain development in Huntington's disease (HD) is abnormal, leading to the idea that HD is not only a neurodegenerative but also a neurodevelopmental disorder. Indeed, structural and functional abnormalities have been observed during brain development in both humans and animal models of HD. However, a concurrent study of cortical and striatal development in a genetic model of HD is still lacking. Here we report significant alterations of corticostriatal development in the R6/2 mouse model of juvenile HD. We examined wildtype (WT) and R6/2 mice at postnatal (P) days 7, 14, and 21. Morphological examination demonstrated early structural and cellular alterations reminiscent of malformations of cortical development, and ex vivo electrophysiological recordings of cortical pyramidal neurons (CPNs) demonstrated significant age- and genotype-dependent changes of intrinsic membrane and synaptic properties. In general, R6/2 CPNs had reduced cell membrane capacitance and increased input resistance (P7 and P14), along with reduced frequency of spontaneous excitatory and inhibitory synaptic events during early development (P7), suggesting delayed cortical maturation. This was confirmed by increased occurrence of GABAA receptor-mediated giant depolarizing potentials at P7. At P14, the rheobase of CPNs was significantly reduced, along with increased excitability. Altered membrane and synaptic properties of R6/2 CPNs recovered progressively, and by P21 they were similar to WT CPNs. In striatal medium-sized spiny neurons (MSNs), a different picture emerged. Intrinsic membrane properties were relatively normal throughout development, except for a transient increase in membrane capacitance at P14. The first alterations in MSNs synaptic activity were observed at P14 and consisted of significant deficits in GABAergic inputs, however, these also were normalized by P21. In contrast, excitatory inputs began to decrease at this age. We conclude that the developing HD brain is capable of compensating for early developmental abnormalities and that cortical alterations precede and are a main contributor of striatal changes. Addressing cortical maldevelopment could help prevent or delay disease manifestations.http://www.sciencedirect.com/science/article/pii/S0969996124003541Juvenile Huntington's diseaseDevelopmentEx vivo electrophysiologySynaptic activityR6/2 mouse
spellingShingle Carlos Cepeda
Sandra M. Holley
Joshua Barry
Katerina D. Oikonomou
Vannah-Wila Yazon
Allison Peng
Deneen Argueta
Michael S. Levine
Corticostriatal maldevelopment in the R6/2 mouse model of juvenile Huntington's disease
Neurobiology of Disease
Juvenile Huntington's disease
Development
Ex vivo electrophysiology
Synaptic activity
R6/2 mouse
title Corticostriatal maldevelopment in the R6/2 mouse model of juvenile Huntington's disease
title_full Corticostriatal maldevelopment in the R6/2 mouse model of juvenile Huntington's disease
title_fullStr Corticostriatal maldevelopment in the R6/2 mouse model of juvenile Huntington's disease
title_full_unstemmed Corticostriatal maldevelopment in the R6/2 mouse model of juvenile Huntington's disease
title_short Corticostriatal maldevelopment in the R6/2 mouse model of juvenile Huntington's disease
title_sort corticostriatal maldevelopment in the r6 2 mouse model of juvenile huntington s disease
topic Juvenile Huntington's disease
Development
Ex vivo electrophysiology
Synaptic activity
R6/2 mouse
url http://www.sciencedirect.com/science/article/pii/S0969996124003541
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