Both gain-of-function and loss-of-function de novo CACNA1A mutations cause severe developmental epileptic encephalopathies in the spectrum of Lennox-Gastaut syndrome

Xiao Jiang, Praveen K. Raju, Nazzareno D'Avanzo, Mathieu Lachance, Julie Pepin, François Dubeau, Wendy G. Mitchell, Luis E. Bello-Espinosa, Tyler M. Pierson, Berge A. Minassian, Jean Claude Lacaille, Elsa Rossignol

Research output: Contribution to journalArticle

Abstract

Objective: Developmental epileptic encephalopathies (DEEs) are genetically heterogeneous severe childhood-onset epilepsies with developmental delay or cognitive deficits. In this study, we explored the pathogenic mechanisms of DEE-associated de novo mutations in the CACNA1A gene. Methods: We studied the functional impact of four de novo DEE-associated CACNA1A mutations, including the previously described p.A713T variant and three novel variants (p.V1396M, p.G230V, and p.I1357S). Mutant cDNAs were expressed in HEK293 cells, and whole-cell voltage-clamp recordings were conducted to test the impacts on CaV2.1 channel function. Channel localization and structure were assessed with immunofluorescence microscopy and three-dimensional (3D) modeling. Results: We find that the G230V and I1357S mutations result in loss-of-function effects with reduced whole-cell current densities and decreased channel expression at the cell membrane. By contrast, the A713T and V1396M variants resulted in gain-of-function effects with increased whole-cell currents and facilitated current activation (hyperpolarized shift). The A713T variant also resulted in slower current decay. 3D modeling predicts conformational changes favoring channel opening for A713T and V1396M. Significance: Our findings suggest that both gain-of-function and loss-of-function CACNA1A mutations are associated with similarly severe DEEs and that functional validation is required to clarify the underlying molecular mechanisms and to guide therapies.

Original languageEnglish (US)
JournalEpilepsia
DOIs
StateAccepted/In press - Jan 1 2019
Externally publishedYes

Fingerprint

Brain Diseases
Mutation
HEK293 Cells
Fluorescence Microscopy
Epilepsy
Complementary DNA
Cell Count
Cell Membrane
Lennox Gastaut Syndrome
Genes
Therapeutics

Keywords

  • Ca2.1
  • CACNA1A
  • de novo mutations
  • epilepsy
  • epileptic encephalopathies
  • immunofluorescence
  • Lennox-Gastaut syndrome
  • patch-clamp
  • structural modeling

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

Cite this

Both gain-of-function and loss-of-function de novo CACNA1A mutations cause severe developmental epileptic encephalopathies in the spectrum of Lennox-Gastaut syndrome. / Jiang, Xiao; Raju, Praveen K.; D'Avanzo, Nazzareno; Lachance, Mathieu; Pepin, Julie; Dubeau, François; Mitchell, Wendy G.; Bello-Espinosa, Luis E.; Pierson, Tyler M.; Minassian, Berge A.; Lacaille, Jean Claude; Rossignol, Elsa.

In: Epilepsia, 01.01.2019.

Research output: Contribution to journalArticle

Jiang, X, Raju, PK, D'Avanzo, N, Lachance, M, Pepin, J, Dubeau, F, Mitchell, WG, Bello-Espinosa, LE, Pierson, TM, Minassian, BA, Lacaille, JC & Rossignol, E 2019, 'Both gain-of-function and loss-of-function de novo CACNA1A mutations cause severe developmental epileptic encephalopathies in the spectrum of Lennox-Gastaut syndrome', Epilepsia. https://doi.org/10.1111/epi.16316
Jiang, Xiao ; Raju, Praveen K. ; D'Avanzo, Nazzareno ; Lachance, Mathieu ; Pepin, Julie ; Dubeau, François ; Mitchell, Wendy G. ; Bello-Espinosa, Luis E. ; Pierson, Tyler M. ; Minassian, Berge A. ; Lacaille, Jean Claude ; Rossignol, Elsa. / Both gain-of-function and loss-of-function de novo CACNA1A mutations cause severe developmental epileptic encephalopathies in the spectrum of Lennox-Gastaut syndrome. In: Epilepsia. 2019.
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abstract = "Objective: Developmental epileptic encephalopathies (DEEs) are genetically heterogeneous severe childhood-onset epilepsies with developmental delay or cognitive deficits. In this study, we explored the pathogenic mechanisms of DEE-associated de novo mutations in the CACNA1A gene. Methods: We studied the functional impact of four de novo DEE-associated CACNA1A mutations, including the previously described p.A713T variant and three novel variants (p.V1396M, p.G230V, and p.I1357S). Mutant cDNAs were expressed in HEK293 cells, and whole-cell voltage-clamp recordings were conducted to test the impacts on CaV2.1 channel function. Channel localization and structure were assessed with immunofluorescence microscopy and three-dimensional (3D) modeling. Results: We find that the G230V and I1357S mutations result in loss-of-function effects with reduced whole-cell current densities and decreased channel expression at the cell membrane. By contrast, the A713T and V1396M variants resulted in gain-of-function effects with increased whole-cell currents and facilitated current activation (hyperpolarized shift). The A713T variant also resulted in slower current decay. 3D modeling predicts conformational changes favoring channel opening for A713T and V1396M. Significance: Our findings suggest that both gain-of-function and loss-of-function CACNA1A mutations are associated with similarly severe DEEs and that functional validation is required to clarify the underlying molecular mechanisms and to guide therapies.",
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T1 - Both gain-of-function and loss-of-function de novo CACNA1A mutations cause severe developmental epileptic encephalopathies in the spectrum of Lennox-Gastaut syndrome

AU - Jiang, Xiao

AU - Raju, Praveen K.

AU - D'Avanzo, Nazzareno

AU - Lachance, Mathieu

AU - Pepin, Julie

AU - Dubeau, François

AU - Mitchell, Wendy G.

AU - Bello-Espinosa, Luis E.

AU - Pierson, Tyler M.

AU - Minassian, Berge A.

AU - Lacaille, Jean Claude

AU - Rossignol, Elsa

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Objective: Developmental epileptic encephalopathies (DEEs) are genetically heterogeneous severe childhood-onset epilepsies with developmental delay or cognitive deficits. In this study, we explored the pathogenic mechanisms of DEE-associated de novo mutations in the CACNA1A gene. Methods: We studied the functional impact of four de novo DEE-associated CACNA1A mutations, including the previously described p.A713T variant and three novel variants (p.V1396M, p.G230V, and p.I1357S). Mutant cDNAs were expressed in HEK293 cells, and whole-cell voltage-clamp recordings were conducted to test the impacts on CaV2.1 channel function. Channel localization and structure were assessed with immunofluorescence microscopy and three-dimensional (3D) modeling. Results: We find that the G230V and I1357S mutations result in loss-of-function effects with reduced whole-cell current densities and decreased channel expression at the cell membrane. By contrast, the A713T and V1396M variants resulted in gain-of-function effects with increased whole-cell currents and facilitated current activation (hyperpolarized shift). The A713T variant also resulted in slower current decay. 3D modeling predicts conformational changes favoring channel opening for A713T and V1396M. Significance: Our findings suggest that both gain-of-function and loss-of-function CACNA1A mutations are associated with similarly severe DEEs and that functional validation is required to clarify the underlying molecular mechanisms and to guide therapies.

AB - Objective: Developmental epileptic encephalopathies (DEEs) are genetically heterogeneous severe childhood-onset epilepsies with developmental delay or cognitive deficits. In this study, we explored the pathogenic mechanisms of DEE-associated de novo mutations in the CACNA1A gene. Methods: We studied the functional impact of four de novo DEE-associated CACNA1A mutations, including the previously described p.A713T variant and three novel variants (p.V1396M, p.G230V, and p.I1357S). Mutant cDNAs were expressed in HEK293 cells, and whole-cell voltage-clamp recordings were conducted to test the impacts on CaV2.1 channel function. Channel localization and structure were assessed with immunofluorescence microscopy and three-dimensional (3D) modeling. Results: We find that the G230V and I1357S mutations result in loss-of-function effects with reduced whole-cell current densities and decreased channel expression at the cell membrane. By contrast, the A713T and V1396M variants resulted in gain-of-function effects with increased whole-cell currents and facilitated current activation (hyperpolarized shift). The A713T variant also resulted in slower current decay. 3D modeling predicts conformational changes favoring channel opening for A713T and V1396M. Significance: Our findings suggest that both gain-of-function and loss-of-function CACNA1A mutations are associated with similarly severe DEEs and that functional validation is required to clarify the underlying molecular mechanisms and to guide therapies.

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KW - Lennox-Gastaut syndrome

KW - patch-clamp

KW - structural modeling

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