Peripheral neuropathy (PN) is an incurable complication of multiple myeloma (MM) which adversely affects patients' quality of life. The important roles that Circular RNAs (circRNAs) play in tumor progression, and exosome-mediated intracellular communication has been recognized as a crucial factor in the pathogenesis of MM. However, the role of exosome-derived circRNAs (exo-circRNAs) in MM and MM-induced PN remains elusive. In this study, we aimed to investigate the correlation between serum exo-circRNAs and MM to preliminarily explore the role of exo-circRNAs in MM-related PN. A cohort of 25 MM patients and 5 healthy control (HC) individuals were enrolled in the study. High-throughput sequencing and qRT PCR validation of serum exo-circRNAs were used to generate the aberrantly expressed exo-circRNAs profiles. Bioinformatics analysis was done using GO, KEGG, miRanda, Targetscan and Metascape. Correlation analysis was conducted between chr2:2744228-2,744,407+ and clinical characteristics of PN. ROC curve, univariate and multivariate COX regression models were conducted to identify the prognostic potential of chr2:2744228-2,744,407+ in the MM-related PN. 265 upregulated circRNAs and 787 downregulated circRNAs, with at least a two-fold difference in expression level in MM patients vs HC, were screened. Bioinformatics analysis indicated that upregulated circRNAs had the potential to facilitate MM-related PN. Furthermore, PCR validated the abundant expression of chr2:2744228-2,744,407+ in the serum exosomes of 25 MM patients. Bioinformatics analysis indicated that chr2:2744228-2,744,407+ might induce MM related PN via the downstream miRNA and GRIN2B axis. Overexpressed chr2:2744228-2,744,407+ in the serum exosomes of MM patients might lead to the downregulation of hsa-miR-6829-3p, elevation of GRIN2B in the serum and PC12 cells, and inhibited cell viability. The correlation analysis indicated that the expression of chr 2:2744228-2,744,407+ was positively correlated with the clinical characteristics of PN. ROC curve, univariate and multivariate COX regression analysis identified that chr2:2744228-2,744,407+ is an independent prognostic factor in the MM related PN. We identified that the abnormal expression of the serum exo-circRNA was correlated with MM-related PN, implying that exo-circRNA has potential as a novel therapeutic target for MM related PN.

Keywords: Cellular communication; Circular RNA; Exosome; Multiple myeloma; Peripheral neuropathy.

Childhood adversity is an early life stressor associated with increased risk of several psychiatric disorders such as depression. Epigenetic changes, primarily DNA methylation, can be affected by early life stress, which in turn might contribute to altered disease susceptibility later in life. One plausible biomarker of early life stress is methylation of the ionotropic glutamate receptor NMDA type subunit 2B (GRIN2B) gene, which has been previously shown to be epigenetically affected by prenatal environmental stressors. Here, we set out to investigate if stress-inducing adversity during childhood is associated with changes in methylation of GRIN2B in adulthood. We studied 186 individuals from a Swedish naturalistic population-based cohort who had provided saliva samples (DNA) as well as information regarding both childhood adversity (CA) and depressive symptoms (dep) (n_CA,dep = 41, n_CA,no-dep = 56, n_no-CA,dep = 40, N_no-CA,no-dep = 49). Methylation at four CpG sites in a regulatory region of GRIN2B was analysed using bisulfite pyrosequencing. Associations for methylation status to childhood adversity and to depression status were investigated using linear regression models. Our study shows that childhood adversity is associated with increased methylation levels of GRIN2B in adulthood, for three of the measured CpGs (p = 0.007, 0.006 and 5 × 10^-14). This indicates that GRIN2B methylation is susceptible to early life stress, and that methylation at this gene is persistent over time. No association was found between GRIN2B methylation and depression status. Yet, this does not rule out a role for alterations in GRIN2B methylation for other neuropsychological outcomes not studied here.

Keywords: Childhood adversity; DNA methylation; Depression; Early life stress; Epigenetics; GRIN2B.

The neuroinflammatory response to peripheral nerve injury is associated with chronic pain and significant changes in the molecular expression profiles of mRNAs in neurons, glia and infiltrating immune cells. Chronic constriction injury (CCI) of the rat sciatic nerve provides an opportunity to mimic neuropathic injury and quantitatively assess behavior and differential gene expression in individual animals. Previously, we have shown that a single intravenous injection of nanoemulsion containing celecoxib (0.24 mg/kg) reduces inflammation of the sciatic nerve and relieves pain-like behavior for up to 6 days. Here, we use this targeted therapy to explore the impact on mRNA expression changes in both pain and pain-relieved states. Sciatic nerve tissue recovered from CCI animals is used to evaluate the mRNA expression profiles utilizing quantitative PCR. We observe mRNA changes consistent with the reduced recruitment of macrophages evident by a reduction in chemokine and cytokine expression. Furthermore, genes associated with adhesion of macrophages, as well as changes in the neuronal and glial mRNAs are observed. Moreover, genes associated with neuropathic pain including Maob, Grin2b/NMDAR2b, TrpV3, IL-6, Cacna1b/Ca_vv2 at the site of injury, pain relief includes partial reversal of the gene expression profiles associated with chronic pain.

Epilepsy is a brain disorder with a global prevalence of 1%. It has been attributed to genetics and environmental factors. Despite efforts to identify the molecular pathology of epilepsy, the underlying mechanism is not understood yet. This study was carried out to compare GRIN2B, BDNF, and IL-1β gene expressions in 50 patients suffering from generalized epilepsy with tonic-colonic seizures and 50 age- and sex-matched healthy subjects using TaqMan Real-time PCR. Our results demonstrated significant upregulation of these genes in people with epilepsy compared with healthy subjects. We also found a positive correlation between GRIN2B and BDNF expression (r2=0.4619, p < 0.0001), BDNF and IL-1β expression (r2 = 0.515, p < 0.0001), and GRIN2B and IL-1β gene expressions (r2 = 0.666, p < 0.0001) which implies the possibility to estimate the expression level of these genes by assessment of expression of one of them. Considering the results of the previous animal studies which showed upregulation of these genes in brain tissues of epileptic animals, the expression levels of GRIN2B, BDNF, and IL-1β in blood samples might be related to their expression in brain samples. Future studies are needed to assess the role of these genes in the pathogenesis of epilepsy and evaluate whether altered expression of these genes along with imaging methods can facilitate subtyping the epilepsy.

Male broiler breeders (n=32) of 55 weeks of age were administered four different doses of capsulated d-aspartate (DA; 0, 100, 200 or 300mgkg-1day-1, p.o. (DA0, DA100, DA200 and DA300 respectively)) for 12 successive weeks to assess reproductive performance, blood testosterone, testicular histology and transcript levels of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc), androgen receptor (AR), LH receptor (LHR), 3β-hydroxysteroid dehydrogenase (3BHSD), proliferating cell nuclear antigen (PCNA), glutamate ionotropic receptor NMDA type subunit 1 (GRIN1) and glutamate ionotropic receptor NMDA type subunit 2B (GRIN2B). Blood samples and ejaculates were collected, and bodyweight was recorded weekly for 10 weeks. AI was performed weekly for the last 2 weeks to determine the number of sperm penetration holes in the perivitelline layer, fertility and hatchability. Testes histology and transcript levels were evaluated in the 12th week. Bodyweight, numbers of Leydig cells and blood vessels, testis index and levels of sperm abnormalities were not affected (P>0.05) by the treatment. However, sperm total and forward motility, plasma membrane integrity and functionality of sperm, ejaculate volume, testosterone concentration and fertility were higher (P<0.05) in both the DA200 and DA300 groups compared with the other groups. In the DA100 and DA200 groups, sperm concentration, number of spermatogonia, thickness of the seminiferous epithelium and the diameter of tubules were significantly higher (P<0.05) than the other DA-treated groups. The number of penetration holes, hatchability and malondialdehyde concentration were higher in the DA200, all DA-treated and DA300 groups respectively compared with the control and other treatment groups. Except for P450scc, AR, LHR and PCNA transcript levels in the DA300 groups, the relative expression of the genes evaluated improved significantly in the other DA-treated groups. Based on these experimental findings, it is concluded that DA improves reproductive performance of aged roosters.

NMDA receptor dysfunction is central to the encephalopathies caused by missense mutations in the NMDA receptor subunit genes. Missense variants of GRIN1, GRIN2A, and GRIN2B cause similar syndromes with varying severity of intellectual impairment, autism, epilepsy, and motor dysfunction. To gain insight into possible biomarkers of NMDAR hypofunction, we asked whether a loss-of-function variant in the Grin1 gene would cause structural changes in the brain that could be detected by MRI. We also studied the developmental trajectory of these changes to determine whether structural changes coincided with reported cognitive impairments in the mice. We performed magnetic resonance imaging in male Grin1-/- knockdown mice (GluN1KD) that were three, six, or twelve weeks old. Deformation-based morphometry was used to assess neuroanatomical differences. Volumetric reductions were detected in substantia nigra and striatum of GluN1KD mice at all ages. Changes in limbic structures were only evident at six weeks of age. Reductions in white matter volumes were first evident at three weeks, and additional deficits were detected at six and twelve weeks. FluoroJade immunofluorescence revealed degenerating neurons in twelve-week old GluN1KD mice. We conclude that Grin1 loss-of-function mutations cause volume reductions in dopaminergic structures early in development, while changes to limbic and white matter structures are delayed and are more pronounced in post-adolescent ages. The evidence of degenerating neurons in the mature brain indicates an ongoing process of cell loss as a consequence of NMDAR hypofunction.

Background: Data from the Global Burden of Disease Study 2016 recently estimated that after opioid and cannabis use disorders, cocaine use disorders were among the most common, with around 5.8 million cases around the world. Several genome-wide expression studies (GWES) for cocaine misuse have been carried out in brain tissues from patients and controls and in mouse and rat models. Objectives: In the current work, we used a convergent functional genomics approach to identify novel candidate genes and pathways for cocaine misuse. Methods: We carried out meta-analyses for available GWES for cocaine misuse in humans and mouse and rat models (three, four, and two GWES, respectively). Multiple lines of evidence (GWES, genome-wide association and epigenomic data) were integrated to prioritize top candidate genes, and a functional enrichment analysis was carried out. Results: Several top candidate genes supported by multiple lines of genomic evidence, and with known roles in brain plasticity, were identified: APP, GRIN2A, GRIN2B, KCNA2, MAP4, PCDH10, PPP3CA, SNCB, and SV2C. An enrichment of genes regulated by the AP1 transcription factor was found. Conclusion: This is the first meta-analysis of GWES for cocaine misuse in humans and mouse and rat models. The analysis of convergence of multiple lines of genome-wide evidence identified novel candidate genes and pathways for cocaine misuse, which are of basic and clinical importance.

OBJECTIVE

Brain structure differences and adolescent alcohol dependence both show substantial heritability. However, exactly which genes are responsible for brain volume variation in adolescents with substance abuse disorders are currently unknown. The aim of this investigation was to determine whether genetic variants previously implicated in psychiatric disorders are associated with variation in brain volume in adolescents with alcohol use disorder (AUD).

METHODS

The cohort consisted of 58 adolescents with DSM-IV AUD and 58 age and gender-matched controls of mixed ancestry ethnicity. An Illumina Infinium iSelect custom 6000 bead chip was used to genotype 5348 single nucleotide polymorphisms (SNPs) in 378 candidate genes. Magnetic resonance images were acquired and volumes of global and regional structures were estimated using voxel-based morphometry. To determine whether any of the genetic variants were associated with brain volume, association analysis was conducted using linear regression in Plink.

RESULTS

From the exploratory analysis, the GRIN2B SNP rs219927 was associated with brain volume in the left posterior cingulate cortex (p<0.05), whereby having a G-allele was associated with a bigger volume.

CONCLUSIONS

The GRIN2B gene is involved in glutamatergic signalling and may be associated with developmental differences in AUD in brain regions such as the posterior cingulate cortex. Such differences may play a role in risk for AUD, and deserve more detailed investigation.

To improve our understanding of the effects of standardized extract of Ginkgo biloba (EGb) as a cognitive enhancer, we investigated the conditioned lick suppression-induced expression (mRNA and protein) of the GluN2B-containing N-methyl-D-aspartic acid receptor (GluN2B-NMDAR), serotonin (5-HT) 1A receptor (5-HT_1AR), gamma-aminobutyric acid type A receptor (GABA_AR) and glial fibrillary acidic protein (GFAP) in the dorsal hippocampal formation (dHF) of untreated and EGb-treated (0.25, 0.5 and 1.0 g.kg^-1) groups of rats. To substantiate our data, we analysed the molecular changes in dHF following treatment with vehicle, with agonists or antagonists of GABA_AR, GluN2B-NMDAR and 5-HT_1AR or with one of these antagonists prior to EGb and fear memory acquisition. Additionally, we performed a pharmacological analysis of the drug-receptor-receptor interactions and their supplemental role in fear memory by blocking individual receptors and analysed the possible changes in expression level with each of the other receptors in the study as well as astrocytes. Our data show for the first time that EGb treatment not only upregulated GluN2B, GABA_AR-α5, and GFAP compared with the control but also differentially upregulated GABA_AR-α1 in the dHF and 5HT_1AR in the CA3. We found that the activation of GABA_ARs (diazepam) and the inactivation of GluN2B-NMDARs (Ro25-6981) or 5-HT_1AR ((S)-WAY100135) resulted in memory impairment. Further, higher doses of EGb treatment reversed the effect of blocking GluN2B (P < 0.001) and 5-HT_1AR (P < 0.001). Here, treatment with Ro25-6981 + EGb or (S)-WAY100135 + EGb prevented the impairment of the acquisition of lick suppression in association with the upregulation or prevention of the downregulation of Grin2b expression as well as the expression of GluN2B-NMDA and/or α1 and α5 subunit-containing GABA_AR in the CA1 (P < 0.0001). Our data are in line with previous findings concerning the necessity of GluN2B for fear memory formation and add to the current knowledge of the role of the GABA_AR-α1 and -α5 subunits and of GluN2B as a target of cognitive enhancers. Furthermore, our data show that these receptors play a complementary role in controlling the neural circuitry in the dHF that seems to be essential to conditioned lick suppression and the modulatory effects of EGb.

The effects of flavonoids have been correlated with their ability to modulate the glutamatergic, serotoninergic, and GABAergic neurotransmission; the major targets of these substances are N-methyl-D-aspartic acid receptor (NMDARs), serotonin type1A receptor (5-HT1ARs), and the gamma-aminobutyric acid type A receptors (GABAARs). Several studies showed that these receptors are involved in the acquisition and extinction of fear memory. This study assessed the effects of treatment prior to conditioning with a flavonoid-rich fraction from the stem bark of Erythrina falcata (FfB) on the acquisition and extinction of the conditioned suppression following pharmacological manipulations and on gene expression in the dorsal hippocampus (DH). Adult male Wistar rats were treated before conditioned fear with FfB, vehicle, an agonist or antagonist of the 5-HT1AR, GABAARs or the GluN2B-NMDAR or one of these antagonists before FfB treatment. The effects of these treatments on fear memory retrieval, extinction training and extinction retrieval were evaluated at 48, 72, and 98 h after conditioning, respectively. We found that activation of GABAARs and inactivation of GluN2B-NMDARs play important roles in the acquisition of lick response suppression. FfB reversed the effect of blocking GluN2B-NMDARs on the conditioned fear and induced the spontaneous recovery. Blocking the 5-HT1AR and the GluN2B-NMDAR before FfB treatment seemed to be associated with weakening of the spontaneous recovery. Expression of analysis of DH samples via qPCR showed that FfB treatment resulted in the overexpression of Htr1a, Grin2a, Gabra5, and Erk2 after the retention test and of Htr1a and Erk2 after the extinction retention test. Moreover, blocking the 5-HT1ARs and the GluN2B-NMDARs before FfB treatment resulted in reduced Htr1a and Grin2b expression after the retention test, but played a distinct role in Grin2a and Erk2 expression, according session evaluated. We show for the first time that the serotoninergic and glutamatergic receptors are important targets for the effect of FfB on the conditioned fear and spontaneous recovery, in which the ERK signaling pathway appears to be modulated. Further, these results provide important information regarding the role of the DH in conditioned suppression. Taken together, our data suggest that FfB represents a potential therapy for preventing or treating memory impairments.

A whole-genome linkage analysis in a Finnish pedigree of eight cases with developmental dyslexia (DD) revealed several regions shared by the affected individuals. Analysis of coding variants from two affected individuals identified rs146011974G>> A (Ala1039Thr), a rare variant within the NCAN gene co-segregating with DD in the pedigree. This variant prompted us to consider this gene as a putative candidate for DD. The RNA expression pattern of the NCAN gene in human tissues was highly correlated (R>> 0.8) with that of the previously suggested DD susceptibility genes KIAA0319, CTNND2, CNTNAP2 and GRIN2B. We investigated the association of common variation in NCAN to brain structures in two data sets: young adults (Brainchild study, Sweden) and infants (FinnBrain study, Finland). In young adults, we found associations between a common genetic variant in NCAN, rs1064395, and white matter volume in the left and right temporoparietal as well as the left inferior frontal brain regions. In infants, this same variant was found to be associated with cingulate and prefrontal grey matter volumes. Our results suggest NCAN as a new candidate gene for DD and indicate that NCAN variants affect brain structure.

We investigated the possible association between two NMDA subunit gene polymorphisms (GRIN2B rs2284411 and GRIN2A rs2229193) and treatment response to methylphenidate (MPH) in attention-deficit/hyperactivity disorder (ADHD).

A total of 75 ADHD patients aged 6-17 years underwent 6 months of MPH administration. Treatment response was defined by changes in scores of the ADHD-IV Rating Scale (ADHD-RS), clinician-rated Clinical Global Impression-Improvement (CGI-I), and Continuous Performance Test (CPT). The association of the GRIN2B and GRIN2A polymorphisms with treatment response was analyzed using logistic regression analyses.

The GRIN2B rs2284411 C/C genotype showed significantly better treatment response as assessed by ADHD-RS inattention ( p=0.009) and CGI-I scores ( p=0.009), and there was a nominally significant association in regard to ADHD-RS hyperactivity-impulsivity ( p=0.028) and total ( p=0.023) scores, after adjusting for age, sex, IQ, baseline Clinical Global Impression-Severity (CGI-S) score, baseline ADHD-RS total score, and final MPH dose. The GRIN2B C/C genotype also showed greater improvement at the CPT response time variability ( p<0.001). The GRIN2A G/G genotype was associated with a greater improvement in commission errors of the CPT compared to the G/A genotype ( p=0.001).

The results suggest that the GRIN2B rs2284411 genotype may be an important predictor of MPH response in ADHD.

Background: Methylmercury (MeHg) is present in fish and is a neurotoxicant at sufficiently high levels. One potential mechanism of MeHg toxicity early in life is epigenetic dysregulation that may affect long-term neurodevelopment. Altered DNA methylation of nervous system-related genes has been associated with adult mental health outcomes.

Objective: To assess associations between prenatal MeHg exposure and DNA methylation (at the cytosine of CG dinucleotides, CpGs) in three nervous system-related genes, encoding brain-derived neurotropic factor (BDNF), glutamate receptor subunit NR2B (GRIN2B), and the glucocorticoid receptor (NR3C1), in children who were exposed to MeHg in utero.

Methods: We tested 406 seven-year-old Seychellois children participating in the Seychelles Child Development Study (Nutrition Cohort 2), who were prenatally exposed to MeHg from maternal fish consumption. Total mercury in maternal hair (prenatal MeHg exposure measure) collected during pregnancy was measured using atomic absorption spectroscopy. Methylation in DNA from the children's saliva was measured by pyrosequencing. To assess associations between prenatal MeHg exposure and CpG methylation at seven years of age, we used multivariable linear regression models adjusted for covariates.

Results: We identified associations with prenatal MeHg exposure for DNA methylation of one GRIN2B CpG and two NR3C1 CpGs out of 12 total CpG sites. Higher prenatal MeHg was associated with higher methylation for each CpG site. For example, NR3C1 CpG3 had an expected increase of 0.03-fold for each additional 1 ppm of prenatal MeHg (B = 0.030, 95% CI 0.001, 0.059; p = 0.047). Several CpG sites associated with MeHg are located in transcription factor binding sites and the observed methylation changes are predicted to lead to lower gene expression.

Conclusions: In a population of people who consume large amounts of fish, we showed that higher prenatal MeHg exposure was associated with differential DNA methylation at seven years of age at specific CpG sites that may influence neurodevelopment and mental health.

Keywords: DNA methylation; Early life; Epigenetic; Fish consumption; MeHg; Methylmercury; Neurodevelopment.

Background: Schizophrenia is a common mental illness whose pathogenesis is still unknown. The vulnerability and stress model in schizophrenia assume that susceptibility to the disease is mainly associated with genes. Of the five symptomatic dimensions of schizophrenia, cognitive impairment appears to be most associated with the pathogenesis of schizophrenia. The aim of the study was to explore whether selected nucleotide variants in GRIN1, GRIN2A, and GRIN2B encoding subunits of the N-methyl-D-aspartate receptor (NMDA-R) receptor occur in a selected group of patients with treatment resistant schizophrenia with cognitive impairment.

Methods: The study included 45 patients diagnosed with super refractory schizophrenia, all with cognitive deficits and chronically psychotic. 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 in the study group.

Conclusion: Results of the study indicated that the selected single-nucleotide variants are not associated both with resistance to clozapine and the presence of cognitive deficits in schizophrenia. It is possible, however, that a more extensive sequencing along with analyzing the expression of these genes may reveal different single-nucleotide variants than those assumed in the study.

Keywords: Clozapine-resistant schizophrenia; Cognitive deficits; NMDA receptor; Single-nucleotide variants.

Alzheimer's disease (AD), the most common type of dementia, is a serious neurodegenerative disease that has no cure yet, but whose symptoms can be alleviated with available medications. Therefore, early and accurate diagnosis of the disease and elucidation of the molecular mechanisms involved in the progression of pathogenesis are critically important. This study aimed to identify dysregulated miRNAs and their target mRNAs through the integrated analysis of miRNA and mRNA expression profiling in AD patients versus unaffected controls. Expression profiles in postmortem brain samples from AD patients and healthy individuals were extracted from the Gene Expression Omnibus database and were analyzed using bioinformatics approaches to identify gene ontologies, pathways, and networks. Finally, the module analysis of the PPI network and hub gene selection was carried out. A total of five differentially expressed miRNAs were extracted from the miRNA dataset, and 4312 differentially expressed mRNAs were obtained from the mRNA dataset. By comparing the DEGs and the putative targets of the altered miRNAs, 116 (3 upregulated and 113 downregulated) coordinated genes were determined. Also, six hub genes (SNAP25, GRIN2A, GRIN2B, DLG2, ATP2B2, and SCN2A) were identified by constructing a PPI network. The results of the present study provide insight into mechanisms such as synaptic machinery and neuronal communication underlying AD pathogenesis, specifically concerning miRNAs.

Keywords: Alzheimer's disease; Differentially expressed genes; Integrated analysis; mRNA; miRNA.

Polymicrogyria is a malformation of cortical development characterized by overfolding and abnormal lamination of the cerebral cortex. Manifestations include epilepsy, speech disturbance and motor and cognitive disability. Causes include acquired prenatal insults and inherited and de novo genetic variants. The proportion of patients with polymicrogyria and a causative germline or mosaic variant is not known. The aim of this study was to identify the monogenic causes of polymicrogyria in a heterogeneous cohort of patients reflective of specialized referral services. Patients with polymicrogyria were recruited from two clinical centres in Australia and Belgium. Patients with evidence of congenital cytomegalovirus infection or causative chromosomal copy number variants were excluded. One hundred and twenty-three patients were tested using deep sequencing gene panels including known and candidate genes for malformations of cortical development. Causative and potentially causative variants were identified and correlated with phenotypic features. Pathogenic or likely pathogenic variants were identified in 25/123 (20.3%) patients. A candidate variant was identified for an additional patient but could not be confirmed as de novo, and therefore it was classified as being of uncertain significance with high clinical relevance. Of the 22 dominant variants identified, 5 were mosaic with allele fractions less than 0.33 and the lowest allele fraction 0.09. The most common causative genes were TUBA1A and PIK3R2. The other eleven causative genes were PIK3CA, NEDD4L, COL4A1, COL4A2, GPSM2, GRIN2B, WDR62, TUBB3, TUBB2B, ACTG1 and FH. A genetic cause was more likely to be identified in the presence of an abnormal head size or additional brain malformations suggestive of a tubulinopathy, such as dysmorphic basal ganglia. A gene panel test provides greater sequencing depth and sensitivity for mosaic variants than whole exome or genome sequencing but is limited to the genes included, potentially missing variants in newly discovered genes. The diagnostic yield of 20.3% indicates that polymicrogyria may be associated with genes not yet known to be associated with brain malformations, brain-specific somatic mutations or non-genetic causes.

Keywords: cortical malformation; epilepsy; genetic testing; high-throughput nucleotide sequencing; somatic mutation.

The α-secretase A disintegrin and metalloprotease 10 (ADAM10) regulates various physiological and pathophysiological processes. Despite its broad functional implications during development, plasticity, and disease, no pharmacological approaches to inhibit ADAM10 in acute brain injury have been reported. Here, we examined the effects of the ADAM10 inhibitor GI254023X on the neurological and histopathological outcome after experimental traumatic brain injury (TBI). C57BL/6N mice were subjected to the controlled cortical impact (CCI) model of TBI or sham procedure and received GI254023X or vehicle during the acute phase of injury (n = 40, 100 mg/kg, 25% DMSO, 0.1 M Na₂CO₃, intraperitoneal, 30 min and 24 h after TBI). GI254023X treatment did not improve neurological deficits from 1 to 7 days post-injury (dpi) but animals treated with GI254023X exhibited smaller brain lesions compared to vehicle treatment. Determination of brain mRNA expression by quantitative PCR showed that TBI-induced up-regulation of Adam10 and Adam17 was not influenced by GI254023X but the up-regulation of the matrix metalloproteinase genes Mmp2 and Mmp9 was attenuated. GI254023X treatment further increased the T cell marker Cd247 but did not affect blood brain barrier integrity, as assessed by Occludin mRNA expression and IgG brain extravasation. However, in agreement with neuroprotective effects of ADAM10 inhibition, GI254023X treatment attenuated axonal injury, as indicated by decreased generation of spectrin breakdown products (SBDPs) and decreased immunostaining using anti-non-phosphorylated neurofilament (SMI-32). Interestingly, reduced axonal injury in GI254023X-treated animals coincided with subtle mRNA dysregulation in the glutamate receptor subunit genes Gria1 and Grin2b. Quantitative PCR also revealed that GI254023X mitigated up-regulation of the pro-inflammatory markers Il6, Tnfa, and Lcn2 but not the up-regulation of the pan-microglia marker Aif1, the M2 microglia marker Arg1 and the reactive astrocyte marker Gfap. Taken together, the ADAM10 inhibitor GI254023X attenuates brain tissue loss, axonal injury and pro-inflammatory gene expression in the CCI model of TBI. These results suggest that ADAM10 may represent a therapeutic target in the acute phase of TBI.

Keywords: ADAM10 (a disintegrin and metalloprotease 10); GI254023X; axonal injury; neuroinflammation; neuroprotection; traumatic brain injury.

Background: Somatic mutations arising from the brain have recently emerged as significant contributors to neurodevelopmental disorders, including childhood intractable epilepsy and cortical malformations. However, whether brain somatic mutations are implicated in schizophrenia (SCZ) is not well established.

Methods: We performed deep whole exome sequencing (average read depth > 550×) of matched dorsolateral prefrontal cortex and peripheral tissues from 27 patients with SCZ and 31 age-matched control individuals, followed by comprehensive and strict analysis of somatic mutations, including mutagenesis signature, substitution patterns, and involved pathways. In particular, we explored the impact of deleterious mutations in GRIN2B through primary neural culture.

Results: We identified an average of 4.9 and 5.6 somatic mutations per exome per brain in patients with SCZ and control individuals, respectively. These mutations presented with average variant allele frequencies of 8.0% in patients with SCZ and 7.6% in control individuals. Although mutational profiles, such as the number and type of mutations, showed no significant difference between patients with SCZ and control individuals, somatic mutations in SCZ brains were significantly enriched for SCZ-related pathways, including dopamine receptor, glutamate receptor, and long-term potentiation pathways. Furthermore, we showed that brain somatic mutations in GRIN2B (encoding glutamate ionotropic NMDA receptor subunit 2B), which were found in two patients with SCZ, disrupted the location of GRIN2B across the surface of dendrites among primary cultured neurons.

Conclusions: Taken together, this study shows that brain somatic mutations are associated with the pathogenesis of SCZ.

Keywords: Brain somatic mutations; Genetic architecture; Glutamate receptor signaling pathways; Grin2B, Low-level somatic mutations; Schizophrenia.

Zhi-Zi-Hou-Po Decoction (ZZHPD) is a well-known traditional Chinese medicine (TCM) that has been widely used in depression. However, the antidepressant mechanism of ZZHPD has not yet been fully elucidated. The purpose of this study was to explore the pharmacological mechanisms of ZZHPD acting on depression by combining ultra flow liquid chromatography with quadrupole time-of-flight mass spectrometry (UFLC-Q-TOF/MS) and network pharmacology strategy. The chemical components of ZZHPD were identified using UFLC-Q-TOF/MS, while the potential drug targets and depression-related targets were collected from databases on the basis of the identified compounds of ZZHPD. Protein-protein interaction (PPI) network, gene ontology (GO), and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analyses were used to unravel potential antidepressant mechanisms. The predicted antidepressant targets from the pharmacology-based analysis were further verified in vivo. As a result, a total of 31 chemical compounds were identified by UFLC-Q-TOF/MS; 514 promising drug targets were mined by using the Swiss Target Prediction; and 527 depression-related target genes were pinpointed by the GeneCards and OMIM databases. STRING database and Cytoscape's topological analysis revealed 80 potential targets related to the antidepressant mechanism of ZZHPD. The KEGG pathway analysis revealed that the antidepressant targets of ZZHPD were mainly involved in dopaminergic synapse, serotonin synapse, cAMP, and mTOR signaling pathways. Furthermore, based on the animal model of depression induced by chronic corticosterone, the regulatory effects of ZZHPD on the expression of MAOA, MAOB, DRD2, CREBBP, AKT1, MAPK1, HTR1A, and GRIN2B mRNA levels as well as the cAMP signaling pathway and monoaminergic metabolism were experimentally verified in rats. Our study revealed that ZZHPD is expounded to target various genes and pathways to perform its antidepressant effect.

Keywords: CAMP signaling pathway; UFLC-Q-TOF/MS; Zhi-Zi-Hou-Po decoction; depression; network pharmacology.

Schizophrenia is a severe and complex mental disorder with high heritability. There is evidence that mutations in the gene of Nmethyl-d-aspartate-type glutamate receptors (NMDAR) are associated with schizophrenia. GRIN2B encodes a subunit of NMDARs, and has been identified as a candidate gene for many psychiatric disorders, especially schizophrenia. In this study, we investigated whether single nucleotide polymorphisms (SNPs) in GRIN2B were associated with schizophrenia. Four SNPs (rs890, rs1806191, rs219872, rs172677) were genotyped in 752 schizophrenic patients and 846 healthy controls of the Chinese Han population. Our results indicate differences in allele and genotype frequencies of rs890 between case and control. These results were assessed by adapting different genetic models (codominant, dominant, recessive, overdominant, log-additive models). After controlling for confounding factors including sex and age, rs890 remained associated with schizophrenia. In addition, rs890 and rs1806191 were found to form a haplotype associated with schizophrenia. In summary, our results indicate that the GRIN2B SNP rs890 might be associated with schizophrenia in the Chinese Han population.

OBJECTIVE

To search for the association between the GRIN2B gene and signs of thought and speech disorders which may be the result of decreased accessibility to the mental lexicon.

METHODS

The association between the GRIN2B polymorphism rs7301328 with semantic verbal fluency and five symptoms of thought and speech disorders, as assessed with the PANSS, was studied in 552 patients with schizophrenia-spectrum disorders.

CONCLUSIONS

There was the association of the GRIN2B gene with verbal fluency and the PANSS item «Difficulty in Abstract Thinking». The association was not modified by verbal fluency. The results suggest that the GRIN2B gene may modify the linguistic processes involved in the retrieval of information from the mental lexicon on the basis of semantic traits and, moreover, contribute to the variability of clinical symptoms of impairment of abstract thinking in patients with schizophrenia. The heterozygous genotype may be protective against the development of thought and speech disorders.