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Petrova M, Margasyuk S, Vorobeva M, Skvortsov D, Dontsova O, Pervouchine DD. BRD2 and BRD3 genes independently evolved RNA structures to control unproductive splicing. NAR Genom Bioinform 2024; 6:lqad113. [PMID: 38226395 PMCID: PMC10789245 DOI: 10.1093/nargab/lqad113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/13/2023] [Accepted: 12/28/2023] [Indexed: 01/17/2024] Open
Abstract
The mammalian BRD2 and BRD3 genes encode structurally related proteins from the bromodomain and extraterminal domain protein family. The expression of BRD2 is regulated by unproductive splicing upon inclusion of exon 3b, which is located in the region encoding a bromodomain. Bioinformatic analysis indicated that BRD2 exon 3b inclusion is controlled by a pair of conserved complementary regions (PCCR) located in the flanking introns. Furthermore, we identified a highly conserved element encoding a cryptic poison exon 5b and a previously unknown PCCR in the intron between exons 5 and 6 of BRD3, however, outside of the homologous bromodomain. Minigene mutagenesis and blockage of RNA structure by antisense oligonucleotides demonstrated that RNA structure controls the rate of inclusion of poison exons. The patterns of BRD2 and BRD3 expression and splicing show downregulation upon inclusion of poison exons, which become skipped in response to transcription elongation slowdown, further confirming a role of PCCRs in unproductive splicing regulation. We conclude that BRD2 and BRD3 independently acquired poison exons and RNA structures to dynamically control unproductive splicing. This study describes a convergent evolution of regulatory unproductive splicing mechanisms in these genes, providing implications for selective modulation of their expression in therapeutic applications.
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Affiliation(s)
- Marina Petrova
- Skolkovo Institute of Science and Technology, Bolshoy Bulvar, 30, str. 1, Moscow 121205, Russia
| | - Sergey Margasyuk
- Skolkovo Institute of Science and Technology, Bolshoy Bulvar, 30, str. 1, Moscow 121205, Russia
| | - Margarita Vorobeva
- Faculty of Chemistry, Moscow State University, GSP-1, 1-3 Leninskiye Gory, Moscow 119991, Russia
| | - Dmitry Skvortsov
- Skolkovo Institute of Science and Technology, Bolshoy Bulvar, 30, str. 1, Moscow 121205, Russia
- Faculty of Chemistry, Moscow State University, GSP-1, 1-3 Leninskiye Gory, Moscow 119991, Russia
| | - Olga A Dontsova
- Skolkovo Institute of Science and Technology, Bolshoy Bulvar, 30, str. 1, Moscow 121205, Russia
- Faculty of Chemistry, Moscow State University, GSP-1, 1-3 Leninskiye Gory, Moscow 119991, Russia
| | - Dmitri D Pervouchine
- Skolkovo Institute of Science and Technology, Bolshoy Bulvar, 30, str. 1, Moscow 121205, Russia
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2
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Tian M, Liu X, Lin S, Wang J, Luo S, Gao L, Chen X, Liang X, Liu Z, He N, Yi Y, Liao W. Variants in BRWD3 associated with X-linked partial epilepsy without intellectual disability. CNS Neurosci Ther 2022; 29:727-735. [PMID: 36514184 PMCID: PMC9873514 DOI: 10.1111/cns.14057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 11/23/2022] [Accepted: 11/27/2022] [Indexed: 12/15/2022] Open
Abstract
AIMS Etiology of the majority patients with idiopathic partial epilepsy (IPE) remains elusive. We thus screened the potential disease-associated variants in the patients with IPE. METHODS Trios-based whole exome sequencing was performed in a cohort of 320 patients with IPE. Frequency and molecular effects of variants were predicted. RESULTS Three novel BRWD3 variants were identified in five unrelated cases with IPE, which were four male cases and one female case. The variants included two recurrent missense variants (c.836C>T/p.Thr279Ile and c.4234A>C/p.Ile1412Leu) and one intronic variant close to splice site (c.2475 + 6A>G). The two missense variants were located in WD40 repeat domain and bromodomain, respectively. They were predicted to be damaging by silico tools and change hydrogen bonds with surrounding amino acids. The frequency of mutant alleles in this cohort was significantly higher than that in the controls of East Asian and all population of gnomAD. All these variants were inherited from the asymptomatic mothers. Four male cases presented frequent seizures at onset, while the female case only had two fever-triggered seizures. They showed good responses to valproate and lamotrigine, then finally became seizure free. All the cases had no intellectual disability. Further analysis demonstrated that all previously reported destructive variants of BRWD3 caused intellectual disability, while missense variants located in WD40 repeat domains and bromodomains of BRWD3 were associated with epilepsy. CONCLUSION BRWD3 gene is potentially associated with X-linked partial epilepsy without intellectual disability. The genotypes and locations of BRWD3 variants may explain for their phenotypic variation.
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Affiliation(s)
- Mao‐Qiang Tian
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical UniversityKey Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of ChinaGuangzhouChina,Department of PediatricsAffiliated Hospital of Zunyi Medical UniversityZunyiChina
| | - Xiao‐Rong Liu
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical UniversityKey Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of ChinaGuangzhouChina
| | - Si‐Mei Lin
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical UniversityKey Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of ChinaGuangzhouChina
| | - Jie Wang
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical UniversityKey Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of ChinaGuangzhouChina
| | - Sheng Luo
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical UniversityKey Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of ChinaGuangzhouChina
| | - Liang‐Di Gao
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical UniversityKey Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of ChinaGuangzhouChina
| | - Xiao‐Bin Chen
- Department of PediatricsThe 900th Hospital of Joint Logistic Support ForceFuzhouChina
| | - Xiao‐Yu Liang
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical UniversityKey Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of ChinaGuangzhouChina
| | - Zhi‐Gang Liu
- Department of Pediatrics, Affiliated Foshan Maternity & Child Healthcare HospitalSouthern Medical UniversityFoshanChina
| | - Na He
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical UniversityKey Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of ChinaGuangzhouChina
| | - Yong‐Hong Yi
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical UniversityKey Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of ChinaGuangzhouChina
| | - Wei‐Ping Liao
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical UniversityKey Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of ChinaGuangzhouChina
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Branigan GL, Olsen KS, Burda I, Haemmerle MW, Ho J, Venuto A, D’Antonio ND, Briggs IE, DiBenedetto AJ. Zebrafish Paralogs brd2a and brd2b Are Needed for Proper Circulatory, Excretory and Central Nervous System Formation and Act as Genetic Antagonists during Development. J Dev Biol 2021; 9:jdb9040046. [PMID: 34842711 PMCID: PMC8629005 DOI: 10.3390/jdb9040046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/24/2021] [Accepted: 10/26/2021] [Indexed: 12/17/2022] Open
Abstract
Brd2 belongs to the BET family of epigenetic transcriptional co-regulators that act as adaptor-scaffolds for the assembly of chromatin-modifying complexes and other factors at target gene promoters. Brd2 is a protooncogene and candidate gene for juvenile myoclonic epilepsy in humans, a homeobox gene regulator in Drosophila, and a maternal-zygotic factor and cell death modulator that is necessary for normal development of the vertebrate central nervous system (CNS). As two copies of Brd2 exist in zebrafish, we use antisense morpholino knockdown to probe the role of paralog Brd2b, as a comparative study to Brd2a, the ortholog of human Brd2. A deficiency in either paralog results in excess cell death and dysmorphology of the CNS, whereas only Brd2b deficiency leads to loss of circulation and occlusion of the pronephric duct. Co-knockdown of both paralogs suppresses single morphant defects, while co-injection of morpholinos with paralogous RNA enhances them, suggesting novel genetic interaction with functional antagonism. Brd2 diversification includes paralog-specific RNA variants, a distinct localization of maternal factors, and shared and unique spatiotemporal expression, providing unique insight into the evolution and potential functions of this gene.
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Affiliation(s)
- Gregory L. Branigan
- Medical Scientist Training Program, Center for Innovation in Brain Science, Department of Pharmacology, University of Arizona College of Medicine-Tucson, 1501 N Campbell Ave., Tucson, AZ 85724, USA;
| | - Kelly S. Olsen
- Biological and Biomedical Sciences Program, Department of Microbiology and Immunology, University of North Carolina School of Medicine-Chapel Hill, 321 S Columbia St., Chapel Hill, NC 27516, USA;
| | - Isabella Burda
- Department of Molecular Biology and Genetics, Weill Institute for Cell & Molecular Biology, Cornell University, 239 Weill Hall, Ithaca, NY 14853, USA;
| | - Matthew W. Haemmerle
- Institute for Diabetes, Obesity, and Metabolism, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania, Room 12-124, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA;
| | - Jason Ho
- Robert Wood Johnson Medical School, Rutgers University, Clinical Academic Building (CAB), 125 Paterson St., New Brunswick, NJ 08901, USA;
| | - Alexandra Venuto
- Department of Biology, East Carolina University, Greenville, NC 27858, USA;
| | - Nicholas D. D’Antonio
- Sidney Kimmel Medical College, Thomas Jefferson University Hospital, 1025 Walnut St. #100, Philadelphia, PA 19107, USA;
| | - Ian E. Briggs
- Department of Biology, Villanova University, 800 Lancaster Ave., Villanova, PA 19085, USA;
| | - Angela J. DiBenedetto
- Department of Biology, Villanova University, 800 Lancaster Ave., Villanova, PA 19085, USA;
- Correspondence:
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Goel D, Srivastava A, Aledo-Serrano Á, Krishnan A, Vohora D. Pharmacotherapy for SARS-CoV-2 and Seizures for drug repurposing presumed on Mechanistic Targets. Curr Mol Pharmacol 2021; 15:832-845. [PMID: 34645381 DOI: 10.2174/1874467214666211013122528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/16/2021] [Accepted: 09/07/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND The currently circulating novel SARS-CoV-2 coronavirus disease (COVID-19) has brought the whole world to a standstill. Recent studies have deciphered the viral genome structure, epidemiology and are in the process of unveiling multiple mechanisms of pathogenesis. Apart from atypical pneumonia and lung disease manifestations, this disease has also been found to be associated with neurological symptoms, which include dizziness, headache, stroke, or seizures, among others. However, a possible direct or indirect association between SARS-CoV-2 and seizures is still not clear. In any manner, it may be of interest to analyze the drugs being used for viral infection in the background of epilepsy or vice versa. OBJECTIVE To identify the most credible drug candidate for COVID-19 in persons with epilepsy or COVID-19 patients experiencing seizures. METHODS A literature search for original and review articles was performed, and further, the Comparative Toxicogenomics Database was used to unearth the most credible drug candidate. RESULTS Our search based on common mechanistic targets affecting SARS-CoV-2 and seizures revealed ivermectin, dexamethasone, anakinra, and tocilizumab for protection against both COVID-19 and seizures. Amongst the antiseizure medications, we found valproic acid as the most probable pharmacotherapy for COVID-19 patients experiencing seizures. CONCLUSION These findings would hopefully provide the basis for initiating further studies on the pathogenesis and drug targeting strategies for this emerging infection accompanied with seizures or in people with epilepsy.
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Affiliation(s)
- Divya Goel
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi. India
| | - Ankit Srivastava
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi. India
| | - Ángel Aledo-Serrano
- Epilepsy Program, Neurology Department, Ruber Internacional Hospital, Madrid. Spain
| | - Anuja Krishnan
- Department of Molecular Medicine, School of Interdisciplinary Sciences, Jamia Hamdard, New Delhi. India
| | - Divya Vohora
- Department of Pharmacology, School of Pharmaceutical Education and Research, Jamia Hamdard, New Delhi. India
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Iyer H, Wahul AB, P K A, Sawant BS, Kumar A. A BRD's (BiRD's) eye view of BET and BRPF bromodomains in neurological diseases. Rev Neurosci 2021; 32:403-426. [PMID: 33661583 DOI: 10.1515/revneuro-2020-0067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/11/2020] [Indexed: 01/18/2023]
Abstract
Neurological disorders (NLDs) are among the top leading causes for disability worldwide. Dramatic changes in the epigenetic topography of the brain and nervous system have been found in many NLDs. Histone lysine acetylation has prevailed as one of the well characterised epigenetic modifications in these diseases. Two instrumental components of the acetylation machinery are the evolutionarily conserved Bromodomain and PHD finger containing (BRPF) and Bromo and Extra terminal domain (BET) family of proteins, also referred to as acetylation 'readers'. Several reasons, including their distinct mechanisms of modulation of gene expression and their property of being highly tractable small molecule targets, have increased their translational relevance. Thus, compounds which demonstrated promising results in targeting these proteins have advanced to clinical trials. They have been established as key role players in pathologies of cancer, cardiac diseases, renal diseases and rheumatic diseases. In addition, studies implicating the role of these bromodomains in NLDs are gaining pace. In this review, we highlight the findings of these studies, and reason for the plausible roles of all BET and BRPF members in NLDs. A comprehensive understanding of their multifaceted functions would be radical in the development of therapeutic interventions.
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Affiliation(s)
- Harish Iyer
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
| | - Abhipradnya B Wahul
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
| | - Annapoorna P K
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
| | - Bharvi S Sawant
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
| | - Arvind Kumar
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
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6
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Balzano E, Pelliccia F, Giunta S. Genome (in)stability at tandem repeats. Semin Cell Dev Biol 2020; 113:97-112. [PMID: 33109442 DOI: 10.1016/j.semcdb.2020.10.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 09/26/2020] [Accepted: 10/10/2020] [Indexed: 12/12/2022]
Abstract
Repeat sequences account for over half of the human genome and represent a significant source of variation that underlies physiological and pathological states. Yet, their study has been hindered due to limitations in short-reads sequencing technology and difficulties in assembly. A important category of repetitive DNA in the human genome is comprised of tandem repeats (TRs), where repetitive units are arranged in a head-to-tail pattern. Compared to other regions of the genome, TRs carry between 10 and 10,000 fold higher mutation rate. There are several mutagenic mechanisms that can give rise to this propensity toward instability, but their precise contribution remains speculative. Given the high degree of homology between these sequences and their arrangement in tandem, once damaged, TRs have an intrinsic propensity to undergo aberrant recombination with non-allelic exchange and generate harmful rearrangements that may undermine the stability of the entire genome. The dynamic mutagenesis at TRs has been found to underlie individual polymorphism associated with neurodegenerative and neuromuscular disorders, as well as complex genetic diseases like cancer and diabetes. Here, we review our current understanding of the surveillance and repair mechanisms operating within these regions, and we describe how alterations in these protective processes can readily trigger mutational signatures found at TRs, ultimately resulting in the pathological correlation between TRs instability and human diseases. Finally, we provide a viewpoint to counter the detrimental effects that TRs pose in light of their selection and conservation, as important drivers of human evolution.
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Affiliation(s)
- Elisa Balzano
- Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, 00185 Roma, Italy
| | - Franca Pelliccia
- Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, 00185 Roma, Italy
| | - Simona Giunta
- The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, 00185 Roma, Italy.
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7
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Liu M, Li Y, Gao S, Yan S, Zhang Q, Liu G, Ji B. A novel target to reduce microglial inflammation and neuronal damage after deep hypothermic circulatory arrest. J Thorac Cardiovasc Surg 2019; 159:2431-2444.e7. [PMID: 31564537 DOI: 10.1016/j.jtcvs.2019.06.115] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/11/2019] [Accepted: 06/22/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND Neuroinflammation acts as a contributor to neurologic deficits after deep hypothermic circulatory arrest. However, the molecular mechanism remains unclear. This study postulates that cold-inducible RNA-binding protein can promote deep hypothermic circulatory arrest-induced neuroinflammation. METHODS Rats were randomly assigned into 3 groups (n = 5, each group): sham group, deep hypothermic circulatory arrest group, and deep hypothermic circulatory arrest + Cirp-/- group (Cirp-/- group). Murine microglial BV2 cells were administered by adeno-associated viral vectors containing cold-inducible RNA-binding protein small interference RNA or negative control small interference RNA at 2 days before 4-hour oxygen-glucose deprivation at 18°C. Microglial activation, cell death, neuroinflammation, and related protein expression were assessed in tissue samples and cell cultures. RESULTS Cold-inducible RNA-binding protein was elevated along with evident neuroinflammation and neuronal damage in rats exposed to deep hypothermic circulatory arrest. In Cirp-/- rats, histologic injury (3.00 [interquartile range, 2.00-3.00] vs 1.00 [interquartile range, 1.00-1.50] neuropathological score, P < .001) and microglial activation (40 ± 4 vs 13 ± 7 CA1 area, P < .001) were alleviated after deep hypothermic circulatory arrest. With RNA-sequencing analysis, this associated with reduction of key proinflammatory cytokines induced by inhibiting Brd2-NF-κB signals. In BV2 cells treated with small interference RNA-cold-inducible RNA-binding protein, similar protective effects were observed, including decreased proinflammatory cytokines and cytotoxicity. Brd2-NF-κB signals were confirmed by the addition of Brd2 inhibitor JQ1. Notably, the conditioned medium from BV2 cells transfected with small interference RNA cold-inducible RNA-binding protein significantly reduced apoptosis in neural SH-SY5Y cells after oxygen-glucose deprivation, which was similar to that after JQ1 administration. CONCLUSIONS Enhanced cold-inducible RNA-binding protein in microglia aggravates neuronal injury by promoting the release of proinflammatory cytokines, which might be mediated through Brd2-NF-κB signals during deep hypothermic circulatory arrest.
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Affiliation(s)
- Mingyue Liu
- Department of Cardiopulmonary Bypass, State Key Laboratory of Cardiovascular Medicine, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yongnan Li
- Department of Cardiopulmonary Bypass, State Key Laboratory of Cardiovascular Medicine, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China; Department of Cardiac Surgery, Lanzhou University Second Hospital, Lanzhou University, Lanzhou, China
| | - Sizhe Gao
- Department of Cardiopulmonary Bypass, State Key Laboratory of Cardiovascular Medicine, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Shujie Yan
- Department of Cardiopulmonary Bypass, State Key Laboratory of Cardiovascular Medicine, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Qiaoni Zhang
- Department of Cardiopulmonary Bypass, State Key Laboratory of Cardiovascular Medicine, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Gang Liu
- Department of Cardiopulmonary Bypass, State Key Laboratory of Cardiovascular Medicine, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Bingyang Ji
- Department of Cardiopulmonary Bypass, State Key Laboratory of Cardiovascular Medicine, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China.
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Lee DJ, Hwang JH, Ha J, Yu GE, Kwon S, Park DH, Kang DG, Kim TW, Park HC, An SM, Kim CW. Identification of a Bromodomain-containing Protein 2 (BRD2) Gene Polymorphic Variant and Its Effects on Pork Quality Traits in Berkshire Pigs. Korean J Food Sci Anim Resour 2018; 38:703-710. [PMID: 30206429 PMCID: PMC6131382 DOI: 10.5851/kosfa.2018.e7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 06/08/2018] [Accepted: 06/14/2018] [Indexed: 01/21/2023] Open
Abstract
Bromodomain-containing protein 2 (BRD2) is a nuclear serine/threonine kinase involved in transcriptional regulation. We investigated the expression and association of the BRD2 gene as a candidate gene for meat quality traits in Berkshire pigs. BRD2 mRNA was expressed at relatively high levels in muscle tissue. Statistical analysis revealed that the c.1709G>C polymorphism of the BRD2 gene was significantly associated with carcass weight, meat color (a*, redness), protein content, cooking loss, water-holding capacity, carcass temperatures 4, 12 and 24 h postmortem, and the 24 h postmortem pH in 384 Berkshire pigs. Therefore, this polymorphism in the porcine BRD2 gene may be used as a candidate genetic marker to improve meat quality traits in pigs.
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Affiliation(s)
- Dong Ju Lee
- Department of Animal Resource Technology, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Jung Hye Hwang
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Jeongim Ha
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Go Eun Yu
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Seulgi Kwon
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Da Hye Park
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Deok Gyeong Kang
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Tae Wan Kim
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Hwa Chun Park
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Sang Mi An
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Chul Wook Kim
- Department of Animal Resource Technology, Gyeongnam National University of Science & Technology, Jinju 52725, Korea.,Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
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9
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Moloney GM, O'Leary OF, Salvo-Romero E, Desbonnet L, Shanahan F, Dinan TG, Clarke G, Cryan JF. Microbial regulation of hippocampal miRNA expression: Implications for transcription of kynurenine pathway enzymes. Behav Brain Res 2017; 334:50-54. [PMID: 28736331 DOI: 10.1016/j.bbr.2017.07.026] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/17/2017] [Accepted: 07/18/2017] [Indexed: 01/15/2023]
Abstract
Increasing evidence points to a functional role of the enteric microbiota in brain development, function and behaviour including the regulation of transcriptional activity in the hippocampus. Changes in CNS miRNA expression may reflect the colonisation status of the gut. Given the pivotal impact of miRNAs on gene expression, our study was based on the hypothesis that gene expression would also be altered in the germ-free state in the hippocampus. We measured miRNAs in the hippocampus of Germ free (GF), conventional (C) and Germ free colonised (exGF) Swiss Webster mice. miRNAs were selected for follow up based on significant differences in expression between groups according to sex and colonisation status. The expression of miR-294-5p was increased in male germ free animals and was normalised following colonisation. Targets of the differentially expressed miRNAs were over-represented in the kynurenine pathway. We show that the microbiota modulates the expression of miRNAs associated with kynurenine pathway metabolism and, demonstrate that the gut microbiota regulates the expression of kynurenine pathway genes in the hippocampus. We also show a sex-specific role for the microbiota in the regulation of miR-294-5p expression in the hippocampus. The gut microbiota plays an important role in modulating small RNAs that influence hippocampal gene expression, a process critical to hippocampal development.
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Affiliation(s)
- Gerard M Moloney
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland.
| | - Olivia F O'Leary
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland.
| | - Eloisa Salvo-Romero
- Laboratory of Neuro-Immuno-Gastroenterology, Digestive Diseases Research Unit, Vall d'Hebron Institut de Recerca, Department of Gastroenterology, Hospital Universitario Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, Spain.
| | - Lieve Desbonnet
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
| | - Fergus Shanahan
- APC Microbiome Institute, University College Cork, Cork, Ireland.
| | - Timothy G Dinan
- Department of Psychiatry and Neurobehavioural Science, University College Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland.
| | - Gerard Clarke
- Department of Psychiatry and Neurobehavioural Science, University College Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland.
| | - John F Cryan
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland.
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10
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Knockdown of epigenetic transcriptional co-regulator Brd2a disrupts apoptosis and proper formation of hindbrain and midbrain-hindbrain boundary (MHB) region in zebrafish. Mech Dev 2017; 146:10-30. [PMID: 28549975 DOI: 10.1016/j.mod.2017.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 05/17/2017] [Accepted: 05/22/2017] [Indexed: 01/03/2023]
Abstract
Brd2 is a member of the bromodomain-extraterminal domain (BET) family of proteins and functions as an acetyl-histone-directed transcriptional co-regulator and recruitment scaffold in chromatin modification complexes affecting signal-dependent transcription. While Brd2 acts as a protooncogene in mammalian blood, developmental studies link it to regulation of neuronal apoptosis and epilepsy, and complete knockout of the gene is invariably embryonic lethal. In Drosophila, the Brd2 homolog acts as a maternal effect factor necessary for segment formation and identity and proper expression of homeotic loci, including Ultrabithorax and engrailed. To test the various roles attributed to Brd2 in a single developmental system representing a non-mammalian vertebrate, we conducted a phenotypic characterization of Brd2a deficient zebrafish embryos produced by morpholino knockdown and corroborated by Crispr-Cas9 disruption and small molecule inhibitor treatments. brd2aMO morphants exhibit reduced hindbrain with an ill-defined midbrain-hindbrain boundary (MHB) region; irregular notochord, neural tube, and somites; and abnormalities in ventral trunk and ventral nerve cord interneuron positioning. Using whole mount TUNEL and confocal microscopy, we uncover a significant decrease, then a dramatic increase, of p53-independent cell death at the start and end of segmentation, respectively. In contrast, using qualitative and quantitative analyses of BrdU incorporation, phosphohistone H3-tagging, and flow cytometry, we detect little effect of Brd2a knockdown on overall proliferation levels in embryos. RNA in situ hybridization shows reduced or absent expression of homeobox gene eng2a and paired box gene pax2a, in the hindbrain domain of the MHB region, and an overabundance of pax2a-positive kidney progenitors, in knockdowns. Together, these results suggest an evolutionarily conserved role for Brd2 in the proper formation and/or patterning of segmented tissues, including the vertebrate CNS, where it acts as a bi-modal regulator of apoptosis, and is necessary, directly or indirectly, for proper expression of genes that pattern the MHB and/or regulate differentiation in the anterior hindbrain.
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Padmanabhan B, Mathur S, Manjula R, Tripathi S. Bromodomain and extra-terminal (BET) family proteins: New therapeutic targets in major diseases. J Biosci 2017; 41:295-311. [PMID: 27240990 DOI: 10.1007/s12038-016-9600-6] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The bromodomains and extra-terminal domain (BET) family proteins recognize acetylated chromatin through their bromodomains (BDs) and help in regulating gene expression. BDs are chromatin 'readers': by interacting with acetylated lysines on the histone tails, they recruit chromatin-regulating proteins on the promoter region to regulate gene expression and repression. Extensive efforts have been employed by scientific communities worldwide to identify and develop potential inhibitors of BET family BDs to regulate protein expression by inhibiting acetylated histone (H3/H4) interactions. Several small molecule inhibitors have been reported, which not only have high affinity but also have high specificity to BET BDs. These developments make BET family proteins an important therapeutic targets for major diseases such as cancer, neurological disorders, obesity and inflammation. Here, we review and discuss the structural biology of BET family BDs and their applications in major diseases.
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Affiliation(s)
- Balasundaram Padmanabhan
- Department of Biophysics, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore 560 029, India
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The Epigenetic Reader BRD2 as a Specific Modulator of PAI-1 Expression in Lipopolysaccharide-Stimulated Mouse Primary Astrocytes. Neurochem Res 2015; 40:2211-9. [PMID: 26349765 DOI: 10.1007/s11064-015-1710-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 08/13/2015] [Accepted: 08/25/2015] [Indexed: 12/19/2022]
Abstract
The post translational modification of lysine acetylation is a key mechanism that regulates chromatin structure. Epigenetic readers, such as the BET domains, are responsible for reading histone lysine acetylation which is a hallmark of open chromatin structure, further providing a scaffold that can be accessed by RNA polymerases as well as transcription factors. Recently, several reports have assessed and highlighted the roles of epigenetic readers in various cellular contexts. However, little is known about their role in the regulation of inflammatory genes, which is critical in exquisitely tuning inflammatory responses to a variety of immune stimuli. In this study, we investigated the role of epigenetic readers BRD2 and BRD4 in the lipopolysaccharide (LPS)-induced immune responses in mouse primary astrocytes. Inflammatory stimulation by LPS showed that the levels of Brd2 mRNA and protein were increased, while Brd4 mRNA levels did not change. Knocking down of Brd2 mRNA using specific small interfering RNA (siRNA) in cultured mouse primary astrocytes inhibited LPS-induced mRNA expression and secretion of plasminogen activator inhibitor-1 (PAI-1). However, no other pro-inflammatory cytokines, such as Il-6, Il-1β and Tnf-α, were affected. Indeed, treatment with bromodomain-containing protein inhibitor, JQ1, blocked Pai-1 mRNA expression through the inhibition of direct BRD2 protein-binding and active histone modification on Pai-1 promoter. Taken together, our data suggest that BRD2 is involved in the modulation of neuroinflammatory responses through PAI-1 and via the regulation of epigenetic reader BET protein, further providing a potential novel therapeutic strategy in neuroinflammatory diseases.
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Sun R, Wu Y, Wang Y, Zang K, Wei H, Wang F, Yu M. DNA methylation regulates bromodomain-containing protein 2 expression during adipocyte differentiation. Mol Cell Biochem 2015; 402:23-31. [DOI: 10.1007/s11010-014-2310-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 12/20/2014] [Indexed: 01/24/2023]
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Subaran RL, Greenberg DA. The Genetics of Common Epilepsy Disorders: Lessons Learned from the Channelopathy Era. CURRENT GENETIC MEDICINE REPORTS 2014. [DOI: 10.1007/s40142-014-0040-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Thompson P, Urayama K, Zheng J, Yang P, Ford M, Buffler P, Chokkalingam A, Lightfoot T, Taylor M. Differences in meiotic recombination rates in childhood acute lymphoblastic leukemia at an MHC class II hotspot close to disease associated haplotypes. PLoS One 2014; 9:e100480. [PMID: 24959916 PMCID: PMC4069019 DOI: 10.1371/journal.pone.0100480] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 05/20/2014] [Indexed: 12/20/2022] Open
Abstract
Childhood Acute Lymphoblastic Leukemia (ALL) is a malignant lymphoid disease of which B-cell precursor- (BCP) and T-cell- (T) ALL are subtypes. The role of alleles encoded by major histocompatibility loci (MHC) have been examined in a number of previous studies and results indicating weak, multi-allele associations between the HLA-DPB1 locus and BCP-ALL suggested a role for immunosusceptibility and possibly infection. Two independent SNP association studies of ALL identified loci approximately 37 kb from one another and flanking a strong meiotic recombination hotspot (DNA3), adjacent to HLA-DOA and centromeric of HLA-DPB1. To determine the relationship between this observation and HLA-DPB1 associations, we constructed high density SNP haplotypes of the 316 kb region from HLA-DMB to COL11A2 in childhood ALL and controls using a UK GWAS data subset and the software PHASE. Of four haplotype blocks identified, predicted haplotypes in Block 1 (centromeric of DNA3) differed significantly between BCP-ALL and controls (P = 0.002) and in Block 4 (including HLA-DPB1) between T-ALL and controls (P = 0.049). Of specific common (>5%) haplotypes in Block 1, two were less frequent in BCP-ALL, and in Block 4 a single haplotype was more frequent in T-ALL, compared to controls. Unexpectedly, we also observed apparent differences in ancestral meiotic recombination rates at DNA3, with BCP-ALL showing increased and T-ALL decreased levels compared to controls. In silico analysis using LDsplit sotware indicated that recombination rates at DNA3 are influenced by flanking loci, including SNPs identified in childhood ALL association studies. The observed differences in rates of meiotic recombination at this hotspot, and potentially others, may be a characteristic of childhood leukemia and contribute to disease susceptibility, alternatively they may reflect interactions between ALL-associated haplotypes in this region.
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Affiliation(s)
- Pamela Thompson
- Paediatric & Familial Cancer Research Group, Institute of Cancer Sciences, University of Manchester, St Mary's Hospital, Manchester, United Kingdom
| | - Kevin Urayama
- School of Public Health, University of California, Berkeley, Berkeley, California, United States of America
- Department of Human Genetics and Disease Diversity, Tokyo Medical and Dental University, Tokyo, Japan
| | - Jie Zheng
- School of Computer Engineering, Nanyang Technological University, Singapore
- Genome Institute of Singapore, A*STAR (Agency for Science, Technology, and Research), Biopolis, Singapore
| | - Peng Yang
- Data Analytics Department, Institute for Infocomm Research, A*STAR, Singapore
| | - Matt Ford
- Research Computing Services, Faculty of Medical and Human Sciences, University of Manchester, Manchester, United Kingdom
| | - Patricia Buffler
- School of Public Health, University of California, Berkeley, Berkeley, California, United States of America
| | - Anand Chokkalingam
- School of Public Health, University of California, Berkeley, Berkeley, California, United States of America
| | | | - Malcolm Taylor
- Independent Researcher, Handforth, Cheshire, United Kingdom
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Remind me again what disease we are studying? A population genetics, genetic analysis, and real data perspective on why progress on identifying genetic influences on common epilepsies has been so slow. PROGRESS IN BRAIN RESEARCH 2014; 213:199-221. [DOI: 10.1016/b978-0-444-63326-2.00011-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Monson MS, Mendoza KM, Velleman SG, Strasburg GM, Reed KM. Expression profiles for genes in the turkey major histocompatibility complex B-locus. Poult Sci 2013; 92:1523-34. [PMID: 23687148 DOI: 10.3382/ps.2012-02951] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The major histocompatibility complex (MHC) is a highly polymorphic region of the genome essential to immune responses and animal health. In galliforms, the MHC is divided into 2 genetically unlinked regions (MHC-B and MHC-Y). Many MHC-B genes are involved in adaptive or innate immunity, yet others have nonimmune or unknown functions. The sequenced MHC-B region of the turkey (Meleagris gallopavo) contains 40 genes, the majority of which are predicted transcripts based on comparison with the chicken or quail, without direct evidence for expression. This study was designed to test for the presence of MHC-B gene transcripts in a panel of immune and nonimmune system tissues from domestic turkeys. This analysis provides the first locus-wide examination of MHC-B gene expression in any avian species. Most MHC-B genes were broadly expressed across tissues. Expression of all predicted genes was verified by reverse-transcription PCR, including B-butyrophilin 2 (BTN2), a predicted gene with no previous evidence for expression in any species. Previously undescribed splice variants were also detected and sequenced from 3 genes. Characterization of MHC-B expression patterns helps elucidate unknown gene functions and potential gene coregulation. Determining turkey MHC-B expression profiles increases our overall understanding of the avian MHC and provides a necessary resource for future research on the immunological response of these genes.
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Affiliation(s)
- M S Monson
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, 55108, USA
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Berkovits BD, Wolgemuth DJ. The role of the double bromodomain-containing BET genes during mammalian spermatogenesis. Curr Top Dev Biol 2013; 102:293-326. [PMID: 23287038 DOI: 10.1016/b978-0-12-416024-8.00011-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The double bromodomain-containing BET (bromodomain and extra terminal) family of proteins is highly conserved from yeast to humans and consists not just of transcriptional regulators but also histone-interacting chromatin remodelers. The four mammalian BET genes are each expressed at unique times during spermatogenesis, and the testis-specific gene Brdt is essential for spermatogenesis. Loss of the first bromodomain of BRDT results in improper/incomplete spermatid elongation and severely morphologically defective sperm. The elongation defects observed in mutant spermatids can be directly tied to altered postmeiotic chromatin architecture. BRDT is required for creation/maintenance of the chromocenter of round spermatids, a structure that forms just after completion of meiosis. The chromocenter creates a defined topology in spermatids, and the presence of multiple chromocenters rather than a single intact chromocenter correlates with loss of spermatid polarity, loss of heterochromatin foci at the nuclear envelope, and loss of proper spermatid elongation. BRDT is not only essential for proper chromatin organization but also involved in regulation of transcription and in cotranscriptional processing. That is, transcription and alternative splicing are altered in spermatocytes and spermatids that lack full-length BRDT. Additionally, the transcription of mRNAs with short 3' UTRs, which is characteristic of round spermatids, is also altered. Examination of the genes regulated by BRDT yields many possible targets that could in part explain the morphologically abnormal sperm produced by the BRDT mutant testes. Thus, BRDT and possibly the other BET genes are required for proper spermatogenesis, which opens up the possibility that the recently discovered small molecule inhibitors of the BET family could be useful as reversible male contraceptives.
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Affiliation(s)
- Binyamin D Berkovits
- Department of Genetics and Development, Columbia University Medical Center, New York, USA
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Bromodomain-Containing Protein 2 gene in photosensitive epilepsy. Seizure 2012; 21:646-8. [DOI: 10.1016/j.seizure.2012.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 05/31/2012] [Accepted: 06/02/2012] [Indexed: 11/20/2022] Open
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Gemayel R, Cho J, Boeynaems S, Verstrepen KJ. Beyond junk-variable tandem repeats as facilitators of rapid evolution of regulatory and coding sequences. Genes (Basel) 2012; 3:461-80. [PMID: 24704980 PMCID: PMC3899988 DOI: 10.3390/genes3030461] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 07/19/2012] [Accepted: 07/21/2012] [Indexed: 01/19/2023] Open
Abstract
Copy Number Variations (CNVs) and Single Nucleotide Polymorphisms (SNPs) have been the major focus of most large-scale comparative genomics studies to date. Here, we discuss a third, largely ignored, type of genetic variation, namely changes in tandem repeat number. Historically, tandem repeats have been designated as non functional “junk” DNA, mostly as a result of their highly unstable nature. With the exception of tandem repeats involved in human neurodegenerative diseases, repeat variation was often believed to be neutral with no phenotypic consequences. Recent studies, however, have shown that as many as 10% to 20% of coding and regulatory sequences in eukaryotes contain an unstable repeat tract. Contrary to initial suggestions, tandem repeat variation can have useful phenotypic consequences. Examples include rapid variation in microbial cell surface, tuning of internal molecular clocks in flies and the dynamic morphological plasticity in mammals. As such, tandem repeats can be useful functional elements that facilitate evolvability and rapid adaptation.
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Affiliation(s)
- Rita Gemayel
- Laboratory for Systems Biology, VIB, Gaston Geenslaan 1, B-3001 Heverlee, Belgium.
| | - Janice Cho
- Laboratory for Systems Biology, VIB, Gaston Geenslaan 1, B-3001 Heverlee, Belgium.
| | - Steven Boeynaems
- Laboratory for Systems Biology, VIB, Gaston Geenslaan 1, B-3001 Heverlee, Belgium.
| | - Kevin J Verstrepen
- Laboratory for Systems Biology, VIB, Gaston Geenslaan 1, B-3001 Heverlee, Belgium.
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Douaud M, Feve K, Pituello F, Gourichon D, Boitard S, Leguern E, Coquerelle G, Vieaud A, Batini C, Naquet R, Vignal A, Tixier-Boichard M, Pitel F. Epilepsy caused by an abnormal alternative splicing with dosage effect of the SV2A gene in a chicken model. PLoS One 2011; 6:e26932. [PMID: 22046416 PMCID: PMC3203167 DOI: 10.1371/journal.pone.0026932] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 10/06/2011] [Indexed: 11/18/2022] Open
Abstract
Photosensitive reflex epilepsy is caused by the combination of an individual's enhanced sensitivity with relevant light stimuli, such as stroboscopic lights or video games. This is the most common reflex epilepsy in humans; it is characterized by the photoparoxysmal response, which is an abnormal electroencephalographic reaction, and seizures triggered by intermittent light stimulation. Here, by using genetic mapping, sequencing and functional analyses, we report that a mutation in the acceptor site of the second intron of SV2A (the gene encoding synaptic vesicle glycoprotein 2A) is causing photosensitive reflex epilepsy in a unique vertebrate model, the Fepi chicken strain, a spontaneous model where the neurological disorder is inherited as an autosomal recessive mutation. This mutation causes an aberrant splicing event and significantly reduces the level of SV2A mRNA in homozygous carriers. Levetiracetam, a second generation antiepileptic drug, is known to bind SV2A, and SV2A knock-out mice develop seizures soon after birth and usually die within three weeks. The Fepi chicken survives to adulthood and responds to levetiracetam, suggesting that the low-level expression of SV2A in these animals is sufficient to allow survival, but does not protect against seizures. Thus, the Fepi chicken model shows that the role of the SV2A pathway in the brain is conserved between birds and mammals, in spite of a large phylogenetic distance. The Fepi model appears particularly useful for further studies of physiopathology of reflex epilepsy, in comparison with induced models of epilepsy in rodents. Consequently, SV2A is a very attractive candidate gene for analysis in the context of both mono- and polygenic generalized epilepsies in humans.
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Affiliation(s)
- Marine Douaud
- INRA-ENVT, Laboratoire de Génétique Cellulaire, Castanet-Tolosan, France
| | - Katia Feve
- INRA-ENVT, Laboratoire de Génétique Cellulaire, Castanet-Tolosan, France
| | - Fabienne Pituello
- CNRS-Université Toulouse III, Centre de Biologie du Développement, Toulouse, France
| | - David Gourichon
- INRA PEAT, Pôle d'Expérimentation Avicole de Tours, Nouzilly, France
| | - Simon Boitard
- INRA-ENVT, Laboratoire de Génétique Cellulaire, Castanet-Tolosan, France
| | - Eric Leguern
- INSERM, Neurogénétique Moléculaire et Cellulaire, Paris, France
| | - Gérard Coquerelle
- INRA, Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Agathe Vieaud
- INRA, Génétique Animale et Biologie Intégrative, Jouy-en-Josas, France
| | - Cesira Batini
- CNRS, Laboratoire de Génétique Moléculaire de la Neurotransmission et des Processus Neurodégénératifs, Paris, France
| | - Robert Naquet
- CNRS, Institut de Neurobiologie Alfred Fessard, Gif-sur-Yvette, France
| | - Alain Vignal
- INRA-ENVT, Laboratoire de Génétique Cellulaire, Castanet-Tolosan, France
| | | | - Frédérique Pitel
- INRA-ENVT, Laboratoire de Génétique Cellulaire, Castanet-Tolosan, France
- * E-mail:
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Velíšek L, Shang E, Velíšková J, Chachua T, Macchiarulo S, Maglakelidze G, Wolgemuth DJ, Greenberg DA. GABAergic neuron deficit as an idiopathic generalized epilepsy mechanism: the role of BRD2 haploinsufficiency in juvenile myoclonic epilepsy. PLoS One 2011; 6:e23656. [PMID: 21887291 PMCID: PMC3161054 DOI: 10.1371/journal.pone.0023656] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 07/22/2011] [Indexed: 11/23/2022] Open
Abstract
Idiopathic generalized epilepsy (IGE) syndromes represent about 30% of all epilepsies. They have strong, but elusive, genetic components and sex-specific seizure expression. Multiple linkage and population association studies have connected the bromodomain-containing gene BRD2 to forms of IGE. In mice, a null mutation at the homologous Brd2 locus results in embryonic lethality while heterozygous Brd2+/− mice are viable and overtly normal. However, using the flurothyl model, we now show, that compared to the Brd2+/+ littermates, Brd2+/− males have a decreased clonic, and females a decreased tonic-clonic, seizure threshold. Additionally, long-term EEG/video recordings captured spontaneous seizures in three out of five recorded Brd2+/− female mice. Anatomical analysis of specific regions of the brain further revealed significant differences in Brd2+/− vs +/+ mice. Specifically, there were decreases in the numbers of GABAergic (parvalbumin- or GAD67-immunopositive) neurons along the basal ganglia pathway, i.e., in the neocortex and striatum of Brd2+/− mice, compared to Brd2+/+ mice. There were also fewer GABAergic neurons in the substantia nigra reticulata (SNR), yet there was a minor, possibly compensatory increase in the GABA producing enzyme GAD67 in these SNR cells. Further, GAD67 expression in the superior colliculus and ventral medial thalamic nucleus, the main SNR outputs, was significantly decreased in Brd2+/− mice, further supporting GABA downregulation. Our data show that the non-channel-encoding, developmentally critical Brd2 gene is associated with i) sex-specific increases in seizure susceptibility, ii) the development of spontaneous seizures, and iii) seizure-related anatomical changes in the GABA system, supporting BRD2's involvement in human IGE.
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Affiliation(s)
- Libor Velíšek
- Department of Cell Biology & Anatomy, New York College of Medicine, Valhalla, New York, United States of America.
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