1
|
Singh J, Wilkins G, Goodman-Vincent E, Chishti S, Bonilla Guerrero R, McFadden L, Zahavi Z, Santosh P. Co-Occurring Methylenetetrahydrofolate Reductase ( MTHFR) rs1801133 and rs1801131 Genotypes as Associative Genetic Modifiers of Clinical Severity in Rett Syndrome. Brain Sci 2024; 14:624. [PMID: 39061365 PMCID: PMC11275218 DOI: 10.3390/brainsci14070624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 07/28/2024] Open
Abstract
AIM Remethylation disorders such as 5,10-methylenetetrahydrofolate reductase (MTHFR) deficiency reduce the remethylation of homocysteine to methionine. The resulting hyperhomocysteinemia can lead to serious neurological consequences and multisystem toxicity. The role of MTHFR genotypes has not been investigated in patients with Rett Syndrome (RTT). In this study, we sought to assess the impact of co-occurring MTHFR genotypes on symptom profiles in RTT. METHOD Using pharmacogenomic (PGx) testing, the MTHFR genetic polymorphisms rs1801133 (c.665C>T mutation) and rs1801131 (c.1286A>C mutation) were determined in 65 patients (18.7 years ± 12.1 [mean ± standard deviation]) with RTT as part of routine clinical care within the Centre for Interventional Paediatric Psychopharmacology (CIPP) Rett Centre, a National and Specialist Child and Adolescent Mental Health Service (CAMHS) in the UK. The clinical severity of patients was assessed using the RTT-anchored Clinical Global Impression Scale (RTT-CGI). RESULTS The clinical severity symptom distribution varied between the homozygous and heterozygous MTHFR rs1801133 and rs1801131 genotypes. Those with the homozygous genotype had a narrower spread of severity scores across several domains (language and communication, ambulation, hand-use and eye contact clinical domains). Patients with the homozygous genotype had statistically significantly greater CGI-Severity scores than individuals with a non-homozygous MTHFR genotype (Z = -2.44, p = 0.015). When comparing the ratings of moderately impaired (4), markedly impaired (5), severely impaired (6) and extremely impaired (7), individuals with the homozygous MTHFR genotype were more impaired than those with the non-homozygous MTHFR genotype (Z = -2.06, p = 0.039). There was no statistically significant difference in the number of prescribed anti-epileptic drugs between the genotypes. CONCLUSIONS Our findings show that in those with a pathogenic RTT genetic variant, co-occurring homozygotic MTHFR rs1801133 and rs1801131 polymorphisms may act as associative genetic modifiers of clinical severity in a subset of patients. Profiling of rs1801133 and rs1801131 in RTT may therefore be useful, especially for high-risk patients who may be at the most risk from symptom deterioration.
Collapse
Affiliation(s)
- Jatinder Singh
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK; (J.S.); (G.W.); (E.G.-V.); (S.C.); (L.M.)
- Centre for Interventional Paediatric Psychopharmacology and Rare Diseases (CIPPRD), South London and Maudsley NHS Foundation Trust, London SE5 8AZ, UK
- Centre for Interventional Paediatric Psychopharmacology (CIPP) Rett Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK
| | - Georgina Wilkins
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK; (J.S.); (G.W.); (E.G.-V.); (S.C.); (L.M.)
- Centre for Interventional Paediatric Psychopharmacology and Rare Diseases (CIPPRD), South London and Maudsley NHS Foundation Trust, London SE5 8AZ, UK
- Centre for Interventional Paediatric Psychopharmacology (CIPP) Rett Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK
| | - Ella Goodman-Vincent
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK; (J.S.); (G.W.); (E.G.-V.); (S.C.); (L.M.)
- Centre for Interventional Paediatric Psychopharmacology and Rare Diseases (CIPPRD), South London and Maudsley NHS Foundation Trust, London SE5 8AZ, UK
- Centre for Interventional Paediatric Psychopharmacology (CIPP) Rett Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK
| | - Samiya Chishti
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK; (J.S.); (G.W.); (E.G.-V.); (S.C.); (L.M.)
- Centre for Interventional Paediatric Psychopharmacology and Rare Diseases (CIPPRD), South London and Maudsley NHS Foundation Trust, London SE5 8AZ, UK
- Centre for Interventional Paediatric Psychopharmacology (CIPP) Rett Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK
| | | | - Leighton McFadden
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK; (J.S.); (G.W.); (E.G.-V.); (S.C.); (L.M.)
- Centre for Interventional Paediatric Psychopharmacology and Rare Diseases (CIPPRD), South London and Maudsley NHS Foundation Trust, London SE5 8AZ, UK
- Centre for Interventional Paediatric Psychopharmacology (CIPP) Rett Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK
| | - Zvi Zahavi
- Myogenes Limited, Borehamwood WD6 4PJ, UK;
| | - Paramala Santosh
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK; (J.S.); (G.W.); (E.G.-V.); (S.C.); (L.M.)
- Centre for Interventional Paediatric Psychopharmacology and Rare Diseases (CIPPRD), South London and Maudsley NHS Foundation Trust, London SE5 8AZ, UK
- Centre for Interventional Paediatric Psychopharmacology (CIPP) Rett Centre, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE5 8AF, UK
| |
Collapse
|
2
|
Besen S, Ozkale Y, Ceylaner S, Noyan A, Erol I. Clinical and laboratory findings and etiologies of genetic homocystinemia: a single-center experience. Acta Neurol Belg 2024; 124:213-222. [PMID: 37728847 DOI: 10.1007/s13760-023-02356-1] [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: 05/03/2023] [Accepted: 07/31/2023] [Indexed: 09/21/2023]
Abstract
BACKGROUND Homocysteine (Hcy) is an endogenous nonprotein sulfur-containing amino acid biosynthesized from methionine by the removal of its terminal methyl group. Hyperhomocysteinemia (HHcy) has been linked to many systemic disorders, including stroke, proteinuria, epilepsy, psychosis, diabetes, lung disease, and liver disease. The clinical effects of high serum Hcy level, also known as hyperhomocysteinemia, have been explained by different mechanisms. However, little has been reported on the clinical and laboratory findings and etiologies of genetic HHcy in children. This study aimed to examine the relationships between clinical features, laboratory findings, and genetic defects of HHcy. METHODS We retrospectively evaluated 20 consecutive children and adolescents with inherited HHcy at the pediatric neurology division of Baskent University, Adana Hospital (Adana, Turkey) between December 2011 and December 2022. RESULTS Our main finding is that the most common cause of genetic HHcy is MTHFR mutation. The other main finding is that the Hcy level was higher in patients with CBS deficiency and intracellular cbl defects than in MTHFR mutations. We also found that clinical presentations of genetic HHcy vary widely, and the most common clinical finding is seizures. Here, we report the first and only case of a cbl defect with nonepileptic myoclonus. We also observed that mild and intermediate HHcy associated with the MTHFR mutation may be related to migraine, vertigo, tension-type headache, and idiopathic intracranial hypertension. Although some of the patients were followed up in tertiary care centers for a long time, they were not diagnosed with HHcy. Therefore, we suggest evaluating Hcy levels in children with unexplained neurological symptoms. CONCLUSIONS Our findings suggest that genetic HHcy might be associated with different clinical manifestations and etiologies. Therefore, we suggest evaluating Hcy levels in children with unexplained neurologic symptoms.
Collapse
Affiliation(s)
- Seyda Besen
- Division of Neurology, Faculty of Medicine, Adana Dr. Turgut Noyan Teaching and Medical Research Center, Baskent University, Adana, Turkey
| | - Yasemin Ozkale
- Division of Pediatrics, Faculty of Medicine, Adana Teaching and Medical Research Center, Baskent University, BarajYolu 1 Durak, Seyhan, 01120, Adana, Turkey.
| | - Serdar Ceylaner
- Clinical Genetics Unit, Intergen Genetics and Rare Diseases Research and Application Center, Ankara, Turkey
| | - Aytul Noyan
- Division of Nephrology, Faculty of Medicine, Adana Dr. Turgut Noyan Teaching and Medical Research Center, Baskent University, Adana, Turkey
| | - Ilknur Erol
- Division of Neurology, Faculty of Medicine, Adana Dr. Turgut Noyan Teaching and Medical Research Center, Baskent University, Adana, Turkey
| |
Collapse
|
3
|
Yakovlev AV, Kurmashova E, Gataulina E, Gerasimova E, Khalilov I, Sitdikova GF. Maternal hyperhomocysteinemia increases seizures susceptibility of neonatal rats. Life Sci 2023; 329:121953. [PMID: 37467884 DOI: 10.1016/j.lfs.2023.121953] [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: 05/26/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 07/21/2023]
Abstract
AIMS Neonatal seizures are severe pathologies which may result in long-term neurological consequences. High plasma concentrations of homocysteine - hyperhomocysteinemia (hHCy) - are associated with epilepsy. In the present study, we evaluated susceptibility to seizure of neonatal rats with prenatal hHCy. MAIN METHODS Prenatal hHCy was induced by feeding females with a high-methionine diet. Experiments were performed on pups during the first three postnatal weeks. Flurothyl-induced epileptic behavior was assessed according to Racine's scale. Epileptiform activity in the hippocampus was recorded using electrophysiological methods. The balance of excitation/inhibition, functional GABAergic inhibition and GABA reversal potential in hippocampal neurons were analyzed. KEY FINDINGS Rats with hHCy developed more severe stages of behavioral patterns during flurothyl-induced epilepsy with shorter latency. Electrophysiological recordings demonstrated higher background neuronal activity in rats with hHCy. Seizure-like events triggered by flurothyl (in vivo) or 4-aminopyridine (in vitro) showed shorter latency, higher power and amplitude. An increased glutamate/GABA synaptic ratio was shown in the pyramidal neurons of rats with hHCy and more slices demonstrated excitation by isoguvacine, a selective GABA(A) receptor agonist, during the first and second postnatal weeks. The GABA driving force and the reversal potential of GABA(A) currents were more positive during the second postnatal week for hHCy rats. SIGNIFICANCE The higher susceptibility to seizures in rats with prenatal hHCy due to a shift in the balance of excitation/inhibition toward excitation may underlie the clinical evidence about the association of hHCy with an increased risk of epilepsy.
Collapse
Affiliation(s)
- A V Yakovlev
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia.
| | - E Kurmashova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - E Gataulina
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - E Gerasimova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - I Khalilov
- Institut de Neurobiologie de la Méditerranée, INMED UMR901 Parc scientifique de Luminy, 163 avenue de Luminy BP13 - 13273, Marseille cedex 09, France; Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| | - G F Sitdikova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str 18, Kazan 420008, Russia
| |
Collapse
|
4
|
Sarecka-Hujar B. Is There a Relation between 677C>T Polymorphism in the MTHFR Gene and the Susceptibility to Epilepsy in Young Patients? A Meta-Analysis. Brain Sci 2021; 11:brainsci11101327. [PMID: 34679392 PMCID: PMC8533948 DOI: 10.3390/brainsci11101327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/03/2021] [Accepted: 10/05/2021] [Indexed: 11/16/2022] Open
Abstract
Background: Numerous data show a role for genetic polymorphisms in the development of epilepsy. Previously, the TT genotype of the MTHFR 677C>T polymorphism was found to be associated with a decreased leucocyte DNA methylation status. Polymorphisms in the MTHFR gene could modify the pharmacodynamics of many drugs. This meta-analysis aimed to assess the relationship between MTHFR 677C>T polymorphism and susceptibility to epilepsy in young patients. Methods: Available databases (PubMed, Embase, Google Scholar, SciELO, and Medline) were searched using specific keywords. Eight studies, published between 1999 and 2019, with 1678 young patients with epilepsy and 1784 controls, met the inclusion criteria. Apart from the total groups, additional analyses in age subgroups (i.e., young adults and children) were conducted. Statistical analyses were conducted using the RevMan 5.4 and MedCalc software. The pooled odds ratio (OR) was estimated with a random- or fixed-effects model depending on the heterogeneity. Analyses were performed for five genetic models, i.e., dominant (CT + TT vs. CC), recessive (TT vs. CC + CT), additive (TT vs. CC), heterozygous (CT vs. CC), and allelic (T vs. C). The publication bias was assessed with the use of Egger's and Begg's tests. Results: Both the MTHFR TT genotype (in the additive model) and the T allele (in the allelic model) significantly increased the risk of epilepsy when the total groups were compared (OR = 1.44, p = 0.002, and OR = 1.183, p = 0.001, respectively). The sensitivity analysis for these models indicated the stability of the results. Similarly, significant results were obtained among young adults for all the genetic models (dominant model: OR = 1.28, p = 0.002; recessive model: OR = 1.48, p = 0.003; additive model: OR = 1.63, p < 0.001; heterozygous model: OR = 1.21, p = 0.028; and allelic model: OR = 1.256, p < 0.001). Those results were also stable and reliable. In the group of children, no relation between 677C>T polymorphism and epilepsy was observed; however, the analysis was based only on three studies, and one study also comprised young adults. No publication bias was demonstrated. Conclusions: The meta-analysis revealed that the carrier state for the T allele as well as the TT genotype of the MTHFR 677C>T polymorphism increases the risk of epilepsy in young adults but not in children.
Collapse
Affiliation(s)
- Beata Sarecka-Hujar
- Department of Basic Biomedical Science, Faculty of Pharmaceutical Sciences in Sosnowiec, Medical University of Silesia in Katowice, 41-200 Sosnowiec, Poland
| |
Collapse
|
5
|
Al-Eitan LN, Al-Dalalah IM, Mustafa MM, Alghamdi MA, Elshammari AK, Khreisat WH, Aljamal HA. Effects of MTHFR and ABCC2 gene polymorphisms on antiepileptic drug responsiveness in Jordanian epileptic patients. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2019; 12:87-95. [PMID: 31354331 PMCID: PMC6572658 DOI: 10.2147/pgpm.s211490] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 05/27/2019] [Indexed: 01/09/2023]
Abstract
Background Epilepsy is one of the most common neurological diseases with unclear etiology where its genetic background and treatment regime still need further exploration. Objectives This study designed to evaluate the pharmacogenomics of MTHFR and ABCC2 genes, and their association with epilepsy susceptibility among Jordanian population. Methods A case-control study was conducted on Jordanian cohort of 296 epileptic patients and 299 healthy individuals. Custom platform array was used to genotype the genetic polymorphisms within MTHFR (rs1801133) and ABCC2 (rs717620, rs3740066, rs2273697) genes. Results This study revealed a significant genetic association of MTHFR rs1801133 polymorphism with susceptibility to generalized in general and generalized tonic-clonic epilepsy (GTCE)(p=0.018 and 0.01, respectively). Regarding ABCC2 gene, rs717620 was of linkage with generalized and GTCE subtypes (p=0.045 and 0.048, respectively), while rs717620 was associated with poor responder patients (p=0.036) with no linkage of the ABCC2 haplotypes. Conclusions MTHFR and ABCC2 polymorphisms showed an association with either epilepsy types in general or subtypes and treatment response among Jordanian population. This study also suggested that these gene polymorphisms have an important role in epilepsy development and drug effectiveness and could be of a great impact in the era of epilepsy diagnosis and treatment.
Collapse
Affiliation(s)
- Laith N Al-Eitan
- Department of Applied Biological Sciences, Jordan University of Science and Technology, Irbid, Jordan.,Department of Biotechnology and Genetic Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - Islam M Al-Dalalah
- Department of Applied Biological Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Mohamed M Mustafa
- Department of Neuroscience, Jordan University of Science and Technology, Irbid, Jordan
| | | | - Afrah K Elshammari
- Queen Rania Hospital for Children, King Hussein Medical Center, Royal Medical Services, Amman, Jordan
| | - Wael H Khreisat
- Queen Rania Hospital for Children, King Hussein Medical Center, Royal Medical Services, Amman, Jordan
| | - Hanan A Aljamal
- Department of Applied Biological Sciences, Jordan University of Science and Technology, Irbid, Jordan
| |
Collapse
|
6
|
Colliva C, Ferrari M, Benatti C, Guerra A, Tascedda F, Blom JMC. Executive functioning in children with epilepsy: Genes matter. Epilepsy Behav 2019; 95:137-147. [PMID: 31054523 DOI: 10.1016/j.yebeh.2019.02.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/18/2019] [Accepted: 02/18/2019] [Indexed: 02/02/2023]
Abstract
Pediatric epilepsy has emerged as a chronic medical disease with a characteristic behavioral and cognitive phenotype, which includes compromised executive functioning (EF) and attention-related deficits. However, considerable interindividual variability exists; children often display very different or even opposite outcomes, and some children are more likely than others to develop neurocognitive problems in the face of similar individual and disease-related problems. The factors responsible for this interindividual variability are still largely unknown, but we do know that some genetic factors render the developing brain more susceptible to damage or traumatic experiences than others. Dopamine availability has a neuromodulatory function in the prefrontal cortex (PFC) and especially affects EF. Dopamine availability relates to polymorphisms in the gene encoding catechol-O-methyltransferase (COMT Val158Met), which in turn is affected by the methylation state of its promoter. Allelic variation of the methylenetetrahydrofolate reductase (MTHFR C677T) gene, alters methylation and may influence the methylation state of the COMT promoter. Given this, we tested the hypothesis that these polymorphisms interact in children with epilepsy, and that variability in allelic expression is associated with variability in cognitive phenotype. Executive function was tested directly and indirectly (parent-rated) in 42 children between 5 and 12 years of age. The MTHFR T allele carriers performed worse than MTHFR homozygous CC carriers on indirect EF, and a significant decline was observed when T allele carriers had at least one met allele of the COMT gene, especially on Working Memory. Direct EF was significantly compromised in COMT Val/Val carriers where reduced dopamine availability seems to confer a higher risk in a test that requests a high degree of executive attention and planning. This finding suggests that in children with epilepsy, genes that influence methylation and dopamine availability affect PFC-related EF. Therefore, we should consider genetic vulnerability as a polygenic risk, which might predispose for a particular phenotype and include specific genetic signatures as part of each patient's behavioral and cognitive profile from the moment that we start to take care of the child.
Collapse
Affiliation(s)
- Chiara Colliva
- Dept. of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | | | - Cristina Benatti
- Dept. of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy; Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - Azzurra Guerra
- Dept. of Medical and Surgical science, University of Modena and Reggio Emilia, Modena, Italy
| | - Fabio Tascedda
- Dept. of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy; Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy
| | - Joan M C Blom
- Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Modena, Italy; Dept. of Education and Human Sciences, University of Modena and Reggio Emilia, Modena, Italy.
| |
Collapse
|
7
|
Abstract
Here, we report the association of the rs694539 variant of nicotinamide-N-methyltransferase gene with epilepsy in a case-control study of 215 patients with epilepsy and 239 healthy controls (χ (2) = 11.641, P = 0.003). The individuals with the GG genotype revealed protection against epilepsy (χ (2) = 5.866, P = 0.015, OR = 0.623, 95 % CI = 0.425-0.915), whereas the individuals with the AA genotype showed statistically significant increased risk for epilepsy (χ (2) = 8.676, P = 0.003, OR = 5.479, 95 % CI = 1.553-19.337). In addition, the G allele was protective against epilepsy (χ (2) = 8.676, P = 0.003, OR = 0.183, 95 % CI = 0.052-0.644); on the contrary, the A allele was a genetic risk factor for epilepsy (χ (2) = 5.866, P = 0.015, OR = 1.604, 95 % CI = 1.093-2.354). Stratification analysis revealed that the association was statistically significant in male patients with epilepsy (χ (2) = 6.682, P = 0.035). However, the statistical power was only 0.33 in female patients with epilepsy (χ (2) = 5.275, P = 0.072). This finding, for the first time, suggests the involvement of the NNMT gene rs694539 variant in the etiology of epilepsy.
Collapse
|
8
|
Sontag JM, Wasek B, Taleski G, Smith J, Arning E, Sontag E, Bottiglieri T. Altered protein phosphatase 2A methylation and Tau phosphorylation in the young and aged brain of methylenetetrahydrofolate reductase (MTHFR) deficient mice. Front Aging Neurosci 2014; 6:214. [PMID: 25202269 PMCID: PMC4141544 DOI: 10.3389/fnagi.2014.00214] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 08/04/2014] [Indexed: 11/13/2022] Open
Abstract
Common functional polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene, a key enzyme in folate and homocysteine metabolism, influence risk for a variety of complex disorders, including developmental, vascular, and neurological diseases. MTHFR deficiency is associated with elevation of homocysteine levels and alterations in the methylation cycle. Here, using young and aged Mthfr knockout mouse models, we show that mild MTHFR deficiency can lead to brain-region specific impairment of the methylation of Ser/Thr protein phosphatase 2A (PP2A). Relative to wild-type controls, decreased expression levels of PP2A and leucine carboxyl methyltransferase (LCMT1) were primarily observed in the hippocampus and cerebellum, and to a lesser extent in the cortex of young null Mthfr (-/-) and aged heterozygous Mthfr (+/-) mice. A marked down regulation of LCMT1 correlated with the loss of PP2A/Bα holoenzymes. Dietary folate deficiency significantly decreased LCMT1, methylated PP2A and PP2A/Bα levels in all brain regions examined from aged Mthfr (+/+) mice, and further exacerbated the regional effects of MTHFR deficiency in aged Mthfr (+/-) mice. In turn, the down regulation of PP2A/Bα was associated with enhanced phosphorylation of Tau, a neuropathological hallmark of Alzheimer's disease (AD). Our findings identify hypomethylation of PP2A enzymes, which are major CNS phosphatases, as a novel mechanism by which MTHFR deficiency and Mthfr gene-diet interactions could lead to disruption of neuronal homeostasis, and increase the risk for a variety of neuropsychiatric disorders, including age-related diseases like sporadic AD.
Collapse
Affiliation(s)
- Jean-Marie Sontag
- School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle and Hunter Medical Research Institute Callaghan, NSW, Australia
| | - Brandi Wasek
- Institute of Metabolic Disease and Baylor Research Institute, Baylor University Medical Center Dallas, TX, USA
| | - Goce Taleski
- School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle and Hunter Medical Research Institute Callaghan, NSW, Australia
| | - Josephine Smith
- School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle and Hunter Medical Research Institute Callaghan, NSW, Australia
| | - Erland Arning
- Institute of Metabolic Disease and Baylor Research Institute, Baylor University Medical Center Dallas, TX, USA
| | - Estelle Sontag
- School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle and Hunter Medical Research Institute Callaghan, NSW, Australia
| | - Teodoro Bottiglieri
- Institute of Metabolic Disease and Baylor Research Institute, Baylor University Medical Center Dallas, TX, USA
| |
Collapse
|