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Publication
Journal: European Journal of Medical Genetics
February/16/2017
Abstract
The short arm of chromosome 16 is one of the less stable regions of our genome, as over 10% of the euchromatic region of 16p is composed of highly complex low copy repeats that are known to be predisposed to rearrangements mediated by non-allelic homologous recombination. The 16p13.3p13.13 molecular region has been defined as the 16p duplication hotspot, and duplications of chromosome 16p13 have recently been confirmed to cause a recognizable syndrome, with CREBBP being the main phenotype-causing gene. To date, only one case report is present in the literature with a 16p13 duplication without CREBBP involvement; we describe here a second analogous case with a not previously reported 16p13.2p13.13 microduplication. This paper allows us to better delineate the clinical features of 16p13 microduplications that do not encompass CREBBP and, concurrently, to narrow the molecular region responsible for congenital heart defects in 16p duplications as well as to propose GRIN2A as a candidate gene for epilepsy.
Publication
Journal: Epilepsia
November/28/2011
Abstract
Photoparoxysmal response (PPR) is a highly heritable electroencephalographic trait characterized by an increased sensitivity to photic stimulation. It may serve as an endophenotype for idiopathic generalized epilepsy. Family linkage studies identified susceptibility loci for PPR on chromosomes 5q35.3, 8q21.13, and 16p13.3. This study aimed to identify key candidate genes within these loci. We used bioinformatics tools for gene prioritization integrating information on biologic function, sequence data, gene expression, and others. The prime candidate gene from this analysis was sequenced in 48 photopositive probands. Presumed functional implications of identified polymorphisms were investigated using bioinformatics methods. The glutamate receptor subunit gene GRIN2A was identified as a prime candidate gene. Sequence analysis revealed various new polymorphisms. None of the identified variants was predicted to be functionally relevant. We objectified the selection of candidate genes for PPR without an a priori hypothesis. Particularly among the various ion channel genes in the linkage regions, GRIN2A was identified as the prime candidate gene. GRIN2A mutations have recently been identified in various epilepsies. Even though our mutation analysis failed to demonstrate direct involvement of GRIN2A in photosensitivity, in silico gene prioritization may provide a useful tool for the identification of candidate genes within large genomic regions.
Publication
Journal: Minerva Pediatrica
May/22/2020
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Publication
Journal: Psychiatric Genetics
October/24/2018
Publication
Journal: Neurological Sciences
May/17/2019
Publication
Journal: Journal of Neurotrauma
December/18/2019
Abstract
Variability in recovery between concussed athletes can be attributed to several risk factors. One risk factor not definitively explored is genetic variation. Genetic variations such as variable number tandem repeats (VNTR) in the promotor region are normal in the population, and can lead to disparities in the amount of protein produced, which could be associated with neuronal recovery. Little research has been conducted to investigate promoter VNTRs within genes responsible for recovery following a concussion. The authors implemented a prospective cohort design using a standardized concussion protocol to diagnose and followed 93 athletes to full recovery at 3 different sites to determine the association between promotor GT(n) VNTR polymorphisms and recovery time within concussed athletes. The GT(n) VNTR within the promoter region of GRIN2A, KCNH2, GRIK1, NEFL were genotyped using capillary electrophoresis. GT(n) VNTR promotor polymorphisms were dichotomized into long (L) and short (s) alleles. Using adjusted negative binomial regression models we found athletes carrying the LL GRIN2A GT(n) VNTR within the promoter region were more likely to experience a prolonged concussion recovery, where they were not able to return to play for approximately 60 days. Additionally, there was a trend towards significance, where the ss NEFL GT(n) Caucasian athletes had prolonged concussion recovery. This could be presumably attributed to altered proteins or protein levels that disrupts neuronal recovery. This pilot study suggests that these VNTRs are associated with prolonged concussion recovery. In future studies we plan to measure the extent to which the L or s alleles alter the level and the activity of the GluNR2a and NEFL proteins that GRIN2A and NEFL produce, respectively.
Publication
Journal: American Journal of Speech-Language Pathology
July/11/2020
Abstract
Purpose Successful oral feeding and speech emergence are dependent upon the coordination of shared oral muscles and facial nerves. We aimed to determine if the speech-associated genes, forkhead box P2 (FOXP2), contactin-associated protein-like 2 (CNTNAP2), glutamate receptor, ionotropic, N-methyl D-aspartate 2A (GRIN2A), and neurexin 1, were detectable in neonatal saliva and could predict feeding outcomes in premature newborns. Method In this prospective, observational, preliminary study, saliva collected from 51 premature infants (gestational ages: 30-34 6/7 weeks) at different stages of oral feeding development underwent gene expression analysis. Binary (+/-) expression profiles were explored and examined in relation to days to achieve full oral feeds. Results GRIN2A and neurexin 1 rarely amplified in neonatal saliva and were not informative. Infants who amplified FOXP2 but not CNTNAP2 at the start of oral feeds achieved oral feeding success 3.20 (95% CI [-2.5, 8.9]) days sooner than other gene combinations. Conclusions FOXP2 and CNTNAP2 may be informative in predicting oral feeding outcomes in newborns. Salivary analysis at the start of oral feeding trials may inform feeding outcomes in this population and warrants further investigation.
Publication
Journal: PLoS ONE
June/3/2021
Abstract
The genetic influence in epilepsy, characterized by unprovoked and recurrent seizures, is through variants in genes critical to brain development and function. We have carried out variant calling in Mesial Temporal Lobe Epilepsy (MTLE) patients by mapping the RNA-Seq data available at SRA, NCBI, USA onto human genome assembly hg-19. We have identified 1,75,641 SNVs in patient samples. These SNVs are distributed over 14700 genes of which 655 are already known to be associated with epilepsy. Large number of variants occur in the 3'-UTR, which is one of the regions involved in the regulation of protein translation through binding of miRNAs and RNA-binding proteins (RBP). We have focused on studying the structure-function relationship of the 3'-UTR SNVs that are common to at-least 10 of the 35 patient samples. For the first time we find SNVs exclusively in the 3'-UTR of FGF12, FAR1, NAPB, SLC1A3, SLC12A6, GRIN2A, CACNB4 and FBXO28 genes. Structural modelling reveals that the variant 3'-UTR segments possess altered secondary and tertiary structures which could affect mRNA stability and binding of RBPs to form proper ribonucleoprotein (RNP) complexes. Secondly, these SNVs have either created or destroyed miRNA-binding sites, and molecular modeling reveals that, where binding sites are created, the additional miRNAs bind strongly to 3'-UTR of only variant mRNAs. These two factors affect protein production thereby creating an imbalance in the amounts of select proteins in the cell. We suggest that in the absence of missense and nonsense variants, protein-activity imbalances associated with MTLE patients can be caused through 3'-UTR variants in relevant genes by the mechanisms mentioned above. 3'-UTR SNV has already been identified as causative variant in the neurological disorder, Tourette syndrome. Inhibition of these miRNA-mRNA bindings could be a novel way of treating drug-resistant MTLE patients. We also suggest that joint occurrence of these SNVs could serve as markers for MTLE. We find, in the present study, SNV-mediated destruction of miRNA binding site in the 3'-UTR of the gene encoding glutamate receptor subunit, and, interestingly, overexpression of one of this receptor subunit is also associated with Febrile Seizures.
Publication
Journal: Frontiers in Oncology
May/23/2021
Abstract
Colorectal mucinous carcinoma (MC) is associated with inferior prognosis and response to treatment compared to adenocarcinoma (AC). The molecular landscapes of MC and adenocarcinoma with mucous composition (AMC) are not well-defined. We aimed to describe the genomic landscape of MC and AMC in a large colorectal cancer cohort. Tumor samples from patients with MC, AMC, or AC were analyzed using next-generation sequencing. MC had a molecular signature distinct from that of AC; genomic features were similar between AMC and MC but not between AMC and AC. HER2 amplification and TP53 and APC mutation rates were lower, whereas SMAD4, PIK3CA, ACVR2A, KMT2D, LRP1, TGFBR2, GRIN2A, BRAF V600E, PTEN, and BRCA2 mutation rates were higher in MC than in AC. The mutation frequencies in MAPK, PI3K, and TGF- pathways were higher, whereas those of cell cycle proteins and Wnt were lower in MC and AMC than in AC. The proportion of hypermutated tumors was significantly higher in MC and AMC than in AC. As MC has a distinct molecular signature from AC, immunotherapy can be potentially applied in treating MC. Similar molecular profiles of AMC and MC suggest that treatment strategies for MC, but not AC, can be used for AMC treatment.
Keywords: adenocarcinoma with mucous composition; colorectal cancer; hypermutated tumor; mucinous adenocarcinoma; next-generation sequencing.
Publication
Journal: Alcoholism: Clinical and Experimental Research
August/27/2021
Abstract
Background: Alcohol intoxication produces ataxia by affecting the cerebellum, which coordinates movements. Fragile X mental retardation (FMR) protein is a complex regulator of RNA and synaptic plasticity implicated in fragile X-associated tremor/ataxia syndrome, which features ataxia and increased Fmr1 mRNA expression resulting from epigenetic dysregulation of FMRP. We recently demonstrated that acute ethanol-induced ataxia is associated with increased cerebellar Fmr1 gene expression via histone modifications in rats, but it is unknown whether similar behavioral and molecular changes occur following chronic ethanol exposure. Here, we investigated the effects of chronic ethanol exposure on ataxia and epigenetically regulated changes in Fmr1 expression in the cerebellum.
Methods: Male adult Sprague-Dawley rats were trained on the accelerating rotarod and then fed with chronic ethanol or a control Lieber-DeCarli diet while undergoing periodic behavioral testing for ataxia during ethanol exposure and withdrawal. Cerebellar tissues were analyzed for expression of the Fmr1 gene and its targets using a real-time quantitative polymerase chain reaction assay. The epigenetic regulation of Fmr1 was also investigated using a chromatin immunoprecipitation assay.
Results: Ataxic behavior measured by the accelerating rotarod behavioral test developed during chronic ethanol treatment and persisted at both the 8-h and 24-h withdrawal time points compared to control diet-fed rats. In addition, chronic ethanol treatment resulted in up-regulated expression of Fmr1 mRNA and increased activating epigenetic marks H3K27 acetylation and H3K4 trimethylation at 2 sites within the Fmr1 promoter. Finally, measurement of the expression of relevant FMRP mRNA targets in the cerebellum showed that chronic ethanol up-regulated cAMP response element binding (CREB) Creb1, Psd95, Grm5, and Grin2b mRNA expression without altering Grin2a, Eaa1, or histone acetyltransferases CREB binding protein (Cbp) or p300 mRNA transcripts.
Conclusions: These results suggest that epigenetic regulation of Fmr1 and subsequent FMRP regulation of target mRNA transcripts constitute neuroadaptations in the cerebellum that may underlie the persistence of ataxic behavior during chronic ethanol exposure and withdrawal.
Keywords: FMR1; ataxia; cerebellum; epigenetics; ethanol.
Publication
Journal: Molecular neuropsychiatry
November/12/2018
Abstract
Given the cognitive and behavioral effects following in utero Δ9-tetrahydrocannabinol (THC) exposure that have been reported in humans and rodents, it is critical to understand the precise consequences of THC on developing human neurons. Here, we utilize excitatory neurons derived from human-induced pluripotent stem cells (hiPSCs), and report that in vitro THC exposure reduced expression of glutamate receptor subunit genes (GRIA1, GRIA2, GRIN2A, and GRIN2B). By expanding these studies across hiPSC-derived neurons from individuals with a variety of genotypes, we believe that a hiPSC-based model will facilitate studies of the interaction of THC exposure and the genetic risk factors underlying neuropsychiatric disease vulnerability.
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Publication
Journal: Genetics and Molecular Research
September/14/2016
Abstract
The gene glutamate receptor, ionotropic, N-methyl D-aspartate 2A (GRIN2A) is associated with development and neuron viability, and our previous studies showed it to be substantially methylated in nasopharyngeal carcinoma, indicating a link to this disease. The aim of this work was to investigate GRIN2A expression and its clinical significance in nasopharyngeal carcinoma, in contrast to nasopharyngitis and nasopharyngeal precancerous lesions. Fifty patients with nasopharyngeal carcinoma were selected as study subjects, while 28 chronic nasopharyngitis patients and 22 individuals with nasopharyngeal precancerous lesions were used as controls. Immunohistochemical analysis was used to study GRIN2A protein expression, and its relationship with nasopharyngeal carcinoma clinical stage and histopathological features were assessed. GRIN2A appeared as yellow staining in the cytoplasm or nucleus. It was strongly expressed in the nasopharyngeal epithelial tissues of patients with chronic nasopharyngitis and in nasopharyngeal precancerous lesions, the proportions of GRIN2A-positive cells being 82.1 and 72.7%, respectively. However, it was weakly expressed in nasopharyngeal carcinoma tissues, with 28.0% of cells testing positive (P < 0.001). No significant difference in the expression of GRIN2A was observed between different clinical stages and pathological grades. We conclude that weak GRIN2A expression is a major feature of nasopharyngeal carcinoma.
Publication
Journal: Comparative Medicine
December/12/2016
Abstract
Many studies have shown that postweaning social isolation (pwSI) alters various behavioral phenotypes, including hippocampusdependent tasks. Here, we report the comprehensive analysis of the expression of glutamatergic and GABAergic neurotransmissionrelated genes in the distinct hippocampal subregions of pwSI rats. Male F344 rats (age, 4 wk) experienced either pwSI or group housing (controls). At 7 wk of age, the hippocampus of each rat was removed and laser-microdissected into the CA1 and CA3 layers of pyramidal cells and the granule cell layer of the dentate gyrus. Subsequently, the expression of glutamatergic- and GABAergic- related genes was analyzed by quantitative RT-PCR. In the CA1 and CA3 pyramidal cell layers, 18 of 24 glutamate receptor subunit genes were at least 1.5-fold increased in expression after pwSI. In particular, the expression of several N-methyl-D-aspartate and kainate receptors (for example, Grin2a in CA1, Grik4 in CA3) was significantly increased after pwSI. In contrast, pwSI tended to decrease the expression of GABAA receptor subunit genes, and Gabra1, Gabra2, Gabra4, Gabra5, Gabrb2, Gabrg1, and Gabrg2 were all significantly decreased in expression compared with the levels in the group-housed rats. These results indicate a subregion- specific increase of glutamate receptors and reduction of GABAA receptors, suggesting that the hippocampal circuits of pwSI rats may be in more excitable states than those of group-housed rats.
Publication
Journal: Frontiers in Pediatrics
November/25/2020
Abstract
Objective: This study aims to analyze the electroclinical characteristics and gene test results of children on the severe end of the epilepsy aphasia spectrum (EAS) and also the correlation of EAS-related GRIN2A genes to explore the genotype-phenotype relationships, as well as potential pathogenic mechanism of EAS. Methods: A retrospective study was conducted on the participants diagnosed with Landau-Kleffner syndrome (LKS), epileptic encephalopathy with continuous spike-and-wave during sleep (CSWS), and atypical benign partial epilepsy (ABPE) at the Children's Hospital of Chongqing Medical University from January 2013 to June 2019. Whole-exome sequencing was performed in six patients, and epileptic panel was carried out in two. In addition, we reviewed all the published literatures reporting EAS patients with pathogenic variants until June 2019 and conducted Gene Ontology (GO) analysis, as well as protein-protein interaction (PPI) network. Results: The mean age at seizure onset was 55.4 ± 27.0 months. The baseline severity of the spike-wave index (SWI) was not significantly correlated with intellectual disability (ID) level. Two pathogenic de novo GRIN2A null variants were identified in patients with ABPE who had less severe ID, despite the electrical status epilepticus during slow-wave sleep (ESES). By literature reviewing, 18 GRIN2A missense mutations and 11 GRIN2A truncating mutations which lead to N-methyl-d-aspartate receptors' loss of function has been reported. Of these mutations, 9 (31.0%) are situated in amino (N)-terminal domain, 6 (20.7%) in linger-binding domain S1, and 10 (34.5%) in linger-binding domain S2. EAS-related genes were enriched in the biological process of chemical synaptic transmission and vocalization (FDR, <0.01). The hub protein in PPI network is GluN2A, which might affect language function via foxp2-srpx2/uPAR signal network. Conclusion: Our data suggested that when children suspected with benign epilepsy of children with centrotemporal spikes (BECTs) have early-onset age, changed seizure semiology, and deterioration of behavior/cognition/motor function, neurologists should be alert of the appearance of ESES. The neuropsychological deterioration in children with EAS might not only be completely affected by electric discharge severity but also genetic etiology. Our finding also enforced the current genotype-phenotype relationship theory about EAS. For EAS children, GRIN2A-FOXP2-SRPX2/uPAR signal network might contribute to the mechanism of their language deficit.
Keywords: Landau-Kleffner syndrome (LKS); atypical benign partial epilepsy (ABPE); epileptic encephalopathy with continuous spike-and-wave during sleep (CSWS); epileptic-aphasia spectrum disorder; genotype-phenotype relationship.
Publication
Journal: Pharmacological Reports
November/24/2020
Abstract
Background: Schizophrenia is a mental disease that affects approximately 1% of the population. Despite over 100 years of research, its pathomechanism has still not been clarified. Cognitive deficits, which are one of the symptomatic dimensions of schizophrenia, usually appear a few years before the first psychotic episode. Therefore, this is why they are probably the clinical manifestation of the primary pathomechanism of schizophrenia. It is also supposed that N-methyl-D-aspartate receptor (NMDA-R) insufficiency in the prefrontal cortex is responsible for cognitive deficits in schizophrenia. The study aimed to examine whether four selected single nucleotide variants in GRIN1, GRIN2A and GRIN2B encoding NMDA-R subunits, of which two have not been tested before, are linked with the selected clinical phenotype of cognitive dysfunction in schizophrenia.
Methods: The study included the targeted group of 117 patients diagnosed with schizophrenia, all with cognitive deficits and in symptomatic remission. DNA fragments including the studied polymorphisms of the NMDA receptors subunit genes were amplified by polymerase chain reaction and subjected to sequencing.
Results: The study did not confirm the presence of any of the four selected single nucleotide variants in GRIN1, GRIN2A and GRIN2B subunits of NMDA-R.
Conclusions: The finding indicates that selected single nucleotide variants in GRIN2A and GRIN2B encoding subunits of the NMDA receptor are not associated with the presence of cognitive deficits in schizophrenia.
Keywords: Cognitive deficits; NMDA receptor; Schizophrenia; Single nucleotide variants.
Publication
Journal: Brain and Development
June/1/2021
Abstract
Background: Memantine is an N-methyl-D-aspartate receptor (NMDA-R) antagonist, approved for dementia, but also studied in pediatric autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD).
Methods: We reviewed children treated with memantine in a single-centre pediatric neurology clinic. Clinical data extracted included age, sex, weight, clinical history, reason for memantine prescription, period of treatment trial and dosage, treatment response, side effects, and concomitant medications.
Results: Eight patients met inclusion criteria with diagnoses including developmental and epileptic encephalopathy, focal epilepsy, ASD, ADHD. Four reported clear cognitive improvement, though two of these started other concurrent treatments at the time of memantine initiation. One of three patients with poorly-controlled epilepsy, a girl with a GRIN2A variant of uncertain significance, had a clear reduction in seizure frequency. No serious adverse events were noted.
Conclusions: Memantine is generally well-tolerated in children, and may have potential benefit for a broad range of pediatric neurodevelopmental disorders.
Keywords: Attention deficit hyperactivity disorder; Autistic spectrum disorder; Developmental and epileptic encephalopathy; GRIN2A; Memantine; N-methyl-D-aspartate receptor.
Publication
Journal: Neurochemistry International
January/28/2013
Abstract
Much evidence exists for the involvement of vesicular zinc in neurotransmission and cortical plasticity. Recent studies have reported that mice deficient in zinc transporter-3 protein (ZnT3) and thus, vesicular zinc, have significant behavioural and biochemical deficits. Here, we examined whether phenotypic differences existed in the barrel cortices of ZnT3 KO mice using functional proteomics and quantitative PCR. Additionally, by manipulating whisker input, we also investigated experience-dependent changes in protein and gene expression, thereby assaying how cortical plasticity is different in the absence of vesicular zinc. The GABA metabolizing protein ABAT was observed in lower abundances consistently in KO mice. Several presynaptic proteins were identified that were abundant in differing amounts between the WT and KO groups in an experience-dependent manner. At baseline, we observed a decrease in the relative expression of Dlg4, Grin2a, Mt3, and Ntrkb genes in KO mice. The reduced expression of Nrtkb persisted with whisker plucking. These data demonstrate that fundamental changes in the expression of proteins and genes important in neurotransmission occur in the absence of vesicular zinc. Furthermore, the complement of experience-dependent changes were different between WT and KO mice, indicating that the lack of vesicular zinc affects the process of cortical plasticity.
Publication
Journal: Food and Chemical Toxicology
September/20/2018
Abstract
To investigate the developmental exposure effect of citreoviridin (CIT) on postnatal hippocampal neurogenesis, pregnant ICR mice were dietary exposed to CIT at 0, 1, 3 and 10 ppm from gestation day 6 to postnatal day (PND) 21 on weaning. Offspring were maintained through PND 77 without CIT exposure. Male offspring were analyzed. At 10 ppm on PND 21, weak changes suggestive of neural stem cell reduction and progenitor cell proliferation were observed. Number of hilar CALB1+ interneurons reduced, suggesting an influence on neurogenesis. In contrast, number of hilar SST+ interneurons increased and Bdnf and Ntrk2 transcripts upregulated in the dentate gyrus, suggesting a facilitation of BDNF-TRKB signaling for progenitor cell proliferation. Transcript expression changes of an outside regulatory system suggested suppressed function of GABAergic interneurons, especially of PVALB+ interneurons for compensation on neural stem cell reduction. At ≥ 3 ppm, number of ARC+ mature granule cells increased, and at 10 ppm, number of hilar GRIA1+ cells increased and Gria2 and Gria3 upregulated, suggesting an operation of AMPA receptor membrane trafficking on the increase of ARC-mediated synaptic plasticity. On PND 77, all the transcript expression changes of the neurogenesis regulatory system except for Grin2d were inverted, suggesting an operation of a homeostatic mechanism on CIT-induced disruptive neurogenesis. Simultaneous downregulation of Grin2a and Grin2d suggests suppression of GABAergic interneuron function to adjust neurogenesis at the normal level. The no-observed-adverse-effect level of CIT for offspring neurogenesis was determined to be 1 ppm, translating to 0.13-0.51 mg/kg body weight/day of maternal oral exposure.
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Publication
Journal: Behavioural Brain Research
November/5/2017
Abstract
Molecular mechanisms of depression-like pathophysiology in female rodent models are less reported compared to males, despite its higher prevalence in human females. Moreover, the stress-response in brain circuitries including reward and cognition circuitries varies with age or hormonal status of the females. So, to understand the stress-induced mood and cognitive disorders in intact females (with ovaries) and ovariectomized (OVX) females, we studied changes in mouse hippocampus, a functionally heterogeneous neural structure involved in both affective and cognitive behaviors. Here, we used a 6-day Chronic Unpredictable Stress (CUS) paradigm in mice to induce depression and related mood disorders. Interestingly, intact females and OVX females showed difference in mood disorder sub-phenotypes to CUS. Similar to an earlier report of CUS affecting the critical reward circuitry structure the nucleus accumbens differently in females with and without ovaries, cognitive behavior in intact females and OVX females also responded differentially to CUS, as evident from Morris Water Maze (MWM) test results. We report that the presence or absence of ovarian hormones, particularly the estrogen, has a significant impact in altering the hippocampus related spatial memory and affective behavior, in females. Our results also illustrate that estrogen administration improves both reward and cognitive behavior, and plays a significant role in alleviating stress-induced despair behavior and enhancing spatial reference memory following a brief 6-day stressful paradigm. Further, it also indicates that the NMDA receptor subunits, GRIN2A and GRIN2B, might mediate the effects of estrogen in the hippocampal functions, thus suggestive of a translational significance of the finding.
Publication
Journal: Osteoarthritis and Cartilage
October/23/2018
Abstract
The chondrocyte circadian clock is altered in osteoarthritis. This change is implicated in the disease-associated changes in chondrocyte phenotype and cartilage loss. Why the clock is changed is unknown. N-methyl-D-aspartate receptors (NMDAR) are critical for regulating the hypothalamic clock. Chondrocytes also express NMDAR and the type of NMDAR subunits expressed changes in osteoarthritis.
OBJECTIVE
To determine if NMDAR regulate the chondrocyte clock and phenotype.
METHODS
Chondrocytes isolated from macroscopically-normal (MN) and osteoarthritic human cartilage were treated with NMDAR antagonists or transfected with GRIN2A or GRIN2B-targetting siRNA. H5 chondrocytes were transfected with GluN2B-expression plasmids. Clock genes and chondrocyte phenotypic markers were measured by RT-qPCR.
RESULTS
PER2 amplitude was higher and BMAL1 amplitude lower in osteoarthritic compared to MN chondrocytes. In osteoarthritic chondrocytes, NMDAR inhibition restored PER2 and BMAL1 expression to levels similar to MN chondrocytes, and resulted in reduced MMP13 and COL10A1. Paradoxically, NMDAR inhibition in MN chondrocytes resulted in increased PER2, decreased BMAL1 and increased MMP13 and COL10A1. Osteoarthritic, but not MN chondrocytes expressed GluN2B NMDAR subunits. GluN2B knockdown in osteoarthritic chondrocytes restored expression of circadian clock components and phenotypic markers to levels similar to MN chondrocytes. Ectopic expression of GluN2B resulted in reduced BMAL1, increased PER2 and altered SOX9, RUNX2 and MMP13 expression. Knockdown of PER2 mitigated the effects of GluN2B on SOX9 and MMP13.
CONCLUSIONS
NMDAR regulate the chondrocyte clock and phenotype suggesting NMDAR may also regulate clocks in other peripheral tissues. GluN2B expression in osteoarthritis may contribute to pathology by altering the chondrocyte clock.
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Publication
Journal: Psychiatria Polska
March/19/2007
Abstract
Recent studies have shown that in the aetiology of attention-deficit hyperactivity disorder (ADHD) genetic factors may be of importance. Biochemical and pharmacological studies reveal a connection between abnormalities of dopaminergic, adrenergic and serotonergic system and ADHD. Therefore genes for enzymes synthesizing or degrading proper neurotransmitters, genes for adequate transporters and receptors and genes for other substances, which altered the level of neurotransmitters, are studied. Many authors describe the connection between ADHD development and the synaptosomal-associated protein 25 (SNAP-25) gene. This protein plays a role in catecholamine secretion. Its higher expression is specific for neurones. SNAP-25 gene mutation may change this protein level, function of synapse and neurotransmitters storage. Acetylcholine receptor alpha4 subunit gene stimulation increases the dopamine level. Therefore this receptor gene may be important in the aetiology of ADHD studies. Other possible factors in ADHD background are substance influence on brain maturation, including N-methyl-D aspartate glutamate receptor 2A gene polymorphism (GRIN2A) and brain derived neurotrophic factor (BDNF) gene. One of the greatest challenges in studying the genetic basis of psychiatric disorders is to find appropriate ways to define the relevant endophenotype. ADHD often coexists with other psychiatric disorders, including specific developmental disorders, conduct disorders, obsessive-compulsive disorder and early onset of bipolar disorder.
Publication
Journal: Reproductive Toxicology
October/15/2016
Abstract
To elucidate the developmental exposure effects of ochratoxin A (OTA) on postnatal hippocampal neurogenesis, pregnant SD rats were provided a diet containing 0, 0.12, 0.6, or 3.0ppm OTA from gestation day 6 to day 21 on weaning after delivery. Offspring were maintained through postnatal day (PND) 77 without OTA exposure. At 3.0ppm, offspring of both sexes showed a transient body weight decrease after weaning. Changes in hippocampal neurogenesis-related parameters as measured in male PND 21 offspring were observed at 3.0ppm. In the subgranular zone (SGZ) of the dentate gyrus, PAX6+ or TBR2+ cells were decreased, while GFAP+ or DCX+ cells did not fluctuate in number, suggesting decreased numbers of type-2 progenitor cells. On the other hand, SGZ cells accumulating malondialdehyde increased. In the hilus of the dentate gyrus, SST+ or CHRNB2+ γ-aminobutyric acid (GABA)-ergic interneurons decreased, accompanied with transcript downregulation of Chrnb2 in the dentate gyrus. These results suggest that maternal exposure to OTA decreased type-2 progenitor cells by reducing hilar GABAergic interneurons innervating type-2 progenitor cells via cholinergic signal downregulation and also by increasing oxidative stress in the SGZ. Transcript levels of neurotrophin (Bdnf), glutamatergic receptors (Gria1, Gria2, and Grin2a), serotonin-synthesizing enzyme, and serotonergic receptors (Tph2, Htr1a, and Htr4) increased in the dentate gyrus, suggesting multiple neuroprotective actions against OTA-induced aberrant neurogenesis. All observed fluctuations were reversed by PND 77. The no-observed-adverse-effect level for offspring neurogenesis was determined to be 0.6ppm, corresponding to 39.3-76.0μg/kg body weight/day.
Publication
Journal: Current Gene Therapy
January/31/2020
Abstract
Gene therapy may provide a valuable alternative for recognized therapeutic approaches to specific types of epilepsy. Focal lesion appears to be best candidate's form of therapeutic approaches for epilepsies. Gene therapy has been explored to generate antiepileptogenic (determent of progress of epilepsy in subject at threat after having an epileptogenic injury), antiseizure (diminution of severity of seizures), and disease-modifying (modification of the instinctive history of the disease) effects. Advancement of innovative therapeutic alternatives, specifically those with the capability to be remedial is assured. Channelopathies are a divergent class of human derangements that are induced by mutation in such genes coding for channel-regulating proteins or ion channels. Considerable number of channelopathies have been described that associate both non-excitable cells along with electrically effective tissues like skeletal, brain and heart or the smooth muscle. Developments in structural biology (Design of ion channels facilitate us to justify how mutations may cause to channelopathies) has advanced significantly in modern time. Considerable number of new studies showing the significance of mutation in mammalian target of rapamycin pathway, NMDA receptors, GABA receptors, potassium channels, G-protein coupled receptors and chromatin alteration are identified. Illustration of meticulous drug in epilepsy targeting new expression of mutations in SCN8A, GRIN2A, GRIN2D and KCNT1 are confered. Possible causes for the dearth of examples of meticulous therapeutic agent for loss-of-function mutations are depicted. In this current review emphasized on how bilological information on genetics along with gene network investigations have indicated that route way disturbed in epilepsy imbricate with another neurodevelopmental character along with cognition. Analysis of gene network attempt hopes to explore contemporary route for epilepsy, to decode epilepsy's association to another neurodevelopmental features and to build a new way to epilepsy medicine disclosure.
Publication
Journal: FASEB Journal
May/31/2020
Abstract
Alzheimer's disease (AD) is the leading cause of dementia with very limited therapeutic options. Amyloid β (Aβ) and phosphorylated Tau (p-Tau) are key pathogenic molecules in AD. P38α-MAPK is specifically activated in AD lesion sites. However, its effects on AD pathogenesis, especially on p-Tau-associated brain pathology, and the underlying molecular mechanisms remain unclear. We mated human APP-transgenic mice and human P301S Tau-transgenic mice with mapk14-floxed and neuron-specific Cre-knock-in mice. We observed that deletion of p38α-MAPK specifically in neurons improves the cognitive function of both 9-month-old APP and Tau-transgenic AD mice, which is associated with decreased Aβ and p-Tau load in the brain. We further used next-generation sequencing to analyze the gene transcription in brains of p38α-MAPK deficient and wild-type APP-transgenic mice, which indicated that deletion of p38α-MAPK regulates the transcription of calcium homeostasis-related genes, especially downregulates the expression of grin2a, a gene encoding NMDAR subunit NR2A. Cell culture experiments further verified that deletion of p38α-MAPK inhibits NMDA-triggered calcium influx and neuronal apoptosis. Our systemic studies of AD pathogenic mechanisms using both APP- and Tau-transgenic mice suggested that deletion of neuronal p38α-MAPK attenuates AD-associated brain pathology and protects neurons in AD pathogenesis. This study supports p38α-MAPK as a novel target for AD therapy.
Keywords: Alzheimer's disease; Mapk14; calcium homeostasis; neurodegeneration; transcriptome analysis.
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