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Bahabry R, Hauser RM, Sánchez RG, Jago SS, Ianov L, Stuckey RJ, Parrish RR, Ver Hoef L, Lubin FD. Alterations in DNA 5-hydroxymethylation patterns in the hippocampus of an experimental model of chronic epilepsy. Neurobiol Dis 2024:106638. [PMID: 39142613 DOI: 10.1016/j.nbd.2024.106638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 07/27/2024] [Accepted: 08/11/2024] [Indexed: 08/16/2024] Open
Abstract
Temporal lobe epilepsy (TLE) is a type of focal epilepsy characterized by spontaneous recurrent seizures originating from the hippocampus. The epigenetic reprogramming hypothesis of epileptogenesis suggests that the development of TLE is associated with alterations in gene transcription changes resulting in a hyperexcitable network in TLE. DNA 5-methylcytosine (5-mC) is an epigenetic mechanism that has been associated with chronic epilepsy. However, the contribution of 5-hydroxymethylcytosine (5-hmC), a product of 5-mC demethylation by the Ten-Eleven Translocation (TET) family proteins in chronic TLE is poorly understood. 5-hmC is abundant in the brain and acts as a stable epigenetic mark altering gene expression through several mechanisms. Here, we found that the levels of bulk DNA 5-hmC but not 5-mC were significantly reduced in the hippocampus of human TLE patients and in the kainic acid (KA) TLE rat model. Using 5-hmC hMeDIP-sequencing, we characterized 5-hmC distribution across the genome and found bidirectional regulation of 5-hmC at intergenic regions within gene bodies. We found that hypohydroxymethylated 5-hmC intergenic regions were associated with several epilepsy-related genes, including Gal, SV2, and Kcnj11 and hyperdroxymethylation 5-hmC intergenic regions were associated with Gad65, TLR4, and Bdnf gene expression. Mechanistically, Tet1 knockdown in the hippocampus was sufficient to decrease 5-hmC levels and increase seizure susceptibility following KA administration. In contrast, Tet1 overexpression in the hippocampus resulted in increased 5-hmC levels associated with improved seizure resiliency in response to KA. These findings suggest an important role for 5-hmC as an epigenetic regulator of epilepsy that can be manipulated to influence seizure outcomes.
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Affiliation(s)
- Rudhab Bahabry
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States of America.
| | - Rebecca M Hauser
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States of America.
| | - Richard G Sánchez
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States of America.
| | - Silvienne Sint Jago
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States of America.
| | - Lara Ianov
- Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL, United States of America.
| | - Remy J Stuckey
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States of America.
| | - R Ryley Parrish
- Department of Cellular and Molecular Biology, Xenon Pharmaceuticals, Burnaby, BC, Canada
| | - Lawrence Ver Hoef
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, United States of America.
| | - Farah D Lubin
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States of America.
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Bahabry R, Hauser RM, Sánchez RG, Jago SS, Ianov L, Stuckey RJ, Parrish RR, Hoef LV, Lubin FD. Alterations in DNA 5-hydroxymethylation Patterns in the Hippocampus of an Experimental Model of Refractory Epilepsy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.03.560698. [PMID: 37873276 PMCID: PMC10592907 DOI: 10.1101/2023.10.03.560698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Temporal lobe epilepsy (TLE) is a type of focal epilepsy characterized by spontaneous recurrent seizures originating from the hippocampus. The epigenetic reprogramming hypothesis of epileptogenesis suggests that the development of TLE is associated with alterations in gene transcription changes resulting in a hyperexcitable network in TLE. DNA 5-methylcytosine (5-mC) is an epigenetic mechanism that has been associated with chronic epilepsy. However, the contribution of 5-hydroxymethylcytosine (5-hmC), a product of 5-mC demethylation by the Ten-Eleven Translocation (TET) family proteins in chronic TLE is poorly understood. 5-hmC is abundant in the brain and acts as a stable epigenetic mark altering gene expression through several mechanisms. Here, we found that the levels of bulk DNA 5-hmC but not 5-mC were significantly reduced in the hippocampus of human TLE patients and in the kainic acid (KA) TLE rat model. Using 5-hmC hMeDIP-sequencing, we characterized 5-hmC distribution across the genome and found bidirectional regulation of 5-hmC at intergenic regions within gene bodies. We found that hypohydroxymethylated 5-hmC intergenic regions were associated with several epilepsy-related genes, including Gal , SV2, and Kcnj11 and hyperdroxymethylation 5-hmC intergenic regions were associated with Gad65 , TLR4 , and Bdnf gene expression. Mechanistically, Tet1 knockdown in the hippocampus was sufficient to decrease 5-hmC levels and increase seizure susceptibility following KA administration. In contrast, Tet1 overexpression in the hippocampus resulted in increased 5-hmC levels associated with improved seizure resiliency in response to KA. These findings suggest an important role for 5-hmC as an epigenetic regulator of epilepsy that can be manipulated to influence seizure outcomes.
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Kumar K, Banerjee J, Tripathi M, Chandra PS, Dixit AB. Epigenetic Regulation of mTOR Pathway in Malformations of Cortical Development. Neurol India 2019; 67:1472-1473. [PMID: 31857538 DOI: 10.4103/0028-3886.273613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Krishan Kumar
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi; Center of Excellence for Epilepsy, AIIMS, New Delhi, India
| | - Jyotirmoy Banerjee
- Center of Excellence for Epilepsy; Department of Biophysics, AIIMS, New Delhi, India
| | - Manjari Tripathi
- Center of Excellence for Epilepsy; Department of Neurology, AIIMS, New Delhi, India
| | - P Sarat Chandra
- Center of Excellence for Epilepsy; Department of Neurosurgery, AIIMS, New Delhi, India
| | - Aparna B Dixit
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi; Center of Excellence for Epilepsy, AIIMS, New Delhi, India
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