Glioma stem cell-derived exosomes induce the transformation of astrocytes via the miR-3065-5p/DLG2 signaling axis.

Tumor-associated astrocytes (TAAs) in the glioblastoma microenvironment play an important role in tumor development and malignant progression initiated by glioma stem cells (GSCs). In the current study, normal human astrocytes (NHAs) were cultured and continuously treated with GSC-derived exosomes (GSC-EXOs) induction to explore the mechanism by which GSCs affect astrocyte remodeling. This study revealed that GSC-EXOs can induce the transformation of NHAs into TAAs, with relatively swollen cell bodies and multiple extended processes. In addition, high proliferation, elevated resistance to temozolomide (TMZ), and increased expression of TAA-related markers (TGF-ß, CD44, and tenascin-C) were observed in the TAAs. Furthermore, GSC-derived exosomal miR-3065-5p could be delivered to NHAs, and miR-3065-5p levels increased significantly in TAAs, as verified by miRNA expression profile sequencing and Reverse transcription polymerase chain reaction. Overexpression of miR-3065-5p also enhanced NHA proliferation, elevated resistance to TMZ, and increased the expression levels of TAA-related markers. In addition, both GSC-EXO-induced and miR-3065-5p-overexpressing NHAs promoted tumorigenesis of GSCs in vivo. Discs Large Homolog 2 (DLG2, downregulated in glioblastoma) is a direct downstream target of miR-3065-5p in TAAs, and DLG2 overexpression could partially reverse the transformation of NHAs into TAAs. Collectively, these data demonstrate that GSC-EXOs induce the transformation of NHAs into TAAs via the miR-3065-5p/DLG2 signaling axis and that TAAs can further promote the tumorigenesis of GSCs. Thus, precisely blocking the interactions between astrocytes and GSCs via exosomes may be a novel strategy to inhibit glioblastoma development, but more in-depth mechanistic studies are still needed.

Novel splicing variant and gonadal mosaicism in DYRK1A gene identified by whole-genome sequencing in multiplex autism spectrum disorder families.

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition with considerable genetic heterogeneity. The disorder is clinically diagnosed based on DSM-5 criteria, featuring deficits in social communication and interaction, along with restricted and repetitive behaviours. Here, we performed whole-genome sequencing (WGS) on four individuals with ASD from two multiplex families (MPX), where more than one individual is affected, to identify potential single nucleotide variants (SNVs) and structural variants (SVs) in coding and non-coding regions. A rigorous bioinformatics pipeline was employed for variant detection, followed by segregation analysis. Our investigation revealed an unreported splicing variant in the DYRK1A gene (c.-77 + 2T > C; IVS1 + 2T > C; NM_001396.5), in heterozygote form in two affected children in one of the families (family B), which was absent in the healthy parents and siblings. This finding suggests the presence of gonadal mosaicism in one of the parents, representing the first documented instance of such inheritance for a variant in the DYRK1A gene associated with ASD. Furthermore, we identified a 50 bp deletion in intron 9 of the DLG2 gene in two affected patients from the same family, confirmed by PCR and Sanger sequencing. In Family A, we identified potential candidate variants associated with ASD shared by the two patients. These findings enhance our understanding of the genetic landscape of ASD, particularly in MPX families, and highlight the utility of WGS in uncovering novel genetic contributions to neurodevelopmental disorders.

DLG2 intragenic exonic deletions reinforce the link to neurodevelopmental disorders and suggest a potential association with congenital anomalies and dysmorphism.

PURPOSE: Multiple studies suggest an association between DLG2 and neurodevelopmental disorders and indicate the haploinsufficiency of this gene; however, few cases have been thoroughly described. We performed additional studies to confirm this clinical association and DLG2 haploinsufficiency. METHODS: Chromosomal microarray analysis was performed on 11,107 patients at the Cytogenetics Laboratory at the University of Alabama at Birmingham. The Database of Genomic Variants-Gold Standard Variants and the Genome Aggregation Database were selected for the association analysis. Fifty-nine patients from the literature and DECIPHER, all having DLG2 intragenic deletions, were included for comprehensive analysis of the distribution of these deletions. RESULTS: A total of 13 patients with DLG2 intragenic deletions, from 10 families in our cohort, were identified. Nine of 10 probands presented with clinical features of neurodevelopmental disorders. Congenital anomalies and dysmorphism were common in our cohort of patients. Association analysis showed that the frequency of DLG2 deletions in our cohort is significantly higher than those in the Database of Genomic Variants-Gold Standard Variants and the Genome Aggregation Database. Most of DLG2 intragenic deletions identified in 69 unrelated patients from our cohort, the literature, and DECIPHER map to the 5' region of the gene, with a hotspot centered around HPin7, exon 8, and HPin8. CONCLUSION: Our findings reinforce the link between DLG2 intragenic deletions and neurodevelopmental disorders, strongly support the haploinsufficiency of this gene, and indicate that these deletions might also have an association with congenital anomalies and dysmorphism.

The loss of DLG2 isoform 7/8, but not isoform 2, is critical in advanced staged neuroblastoma.

BACKGROUND: Neuroblastoma is a childhood neural crest tumor showing large clinical and genetic heterogeneity, one form displaying 11q-deletion is very aggressive. It has been shown that 11q-deletion results in decreased expression of DLG2, a gene residing in the deleted region. DLG2 has a number of different isoforms with the main difference is the presence or absence of a L27 domain. The L27 domain containing DLG proteins can form complexes with CASK/MPP and LIN7 protein family members, which will control cell polarity and signaling. METHODS: We evaluated the DLG gene family and the LIN7 gene family for their expression in differently INSS staged neuroblastoma from publically available data and primary tumors, we included two distinct DLG1 and DLG2 N-terminal transcript isoforms encoding L27 domains for their expression. Functionality of DLG2 isoforms and of LIN7A were evaluated in the 11q-deleted neuroblastoma cell line SKNAS. RESULTS: In neuroblastoma only two DLG2 isoforms were expressed: isoform 2 and isoform 7/8. Using the array data we could determine that higher expression of DLG members that contain L27 domains correlated to better survival and prognosis. Whilst DLG1 showed a decrease in both isoforms with increased INSS stage, only the full length L27 containing DLG2 transcripts DLG2-isoform 7/8 showed a decrease in expression in high stage neuroblastoma. We could show that the protein encoded by DLG2-isoform 7 could bind to LIN7A, and increased DLG2-isoform 7 gene expression increased the expression of LIN7A, this reduced neuroblastoma cell proliferation and viability, with increased BAX/BCL2 ratio indicating increased apoptosis. CONCLUSION: We have provided evidence that gene expression of the L27 domain containing DLG2-isoform 7/8 but not L27 domain lacking DLG2-isoform 2 is disrupted in neuroblastoma, in particular in the aggressive subsets of tumors. The presence of the complete L27 domain allows for the binding to LIN7A, which will control cell polarity and signaling, thus affecting cancer cell viability.

SNPs in SNCA, MCCC1, DLG2, GBF1 and MBNL2 are associated with Parkinson's disease in southern Chinese population.

Numerous single nucleotide polymorphisms (SNPs), which have been identified as susceptibility factors for Parkinson's disease (PD) as per genome-wide association studies, have not been fully characterized for PD patients in China. This study aimed to replicate the relationship between 12 novel SNPs of 12 genes and PD risk in southern Chinese population. Twelve SNPs of 12 genes were detected in 231 PD patients and 249 controls, using the SNaPshot technique. Meta-analysis was used to assess heterogeneity of effect sizes between this study and published data. The impact of SNPs on gene expression was investigated by analysing the SNP-gene association in the expression quantitative trait loci (eQTL) data sets. rs8180209 of SNCA (allele model: P = .047, OR = 0.77; additive model: P = .047, OR = 0.77), rs2270968 of MCCC1 (dominant model: P = .024, OR = 1.52), rs7479949 of DLG2 (recessive model; P = .019, OR = 1.52), rs10748818 of GBF1 (additive model: P < .001, OR = 0.37), and rs4771268 of MBNL2 (recessive model: P = .003, OR = 0.48) were replicated to be significantly associated with the increased risk of PD. Noteworthy, a meta-analysis of previous studies suggested rs8180209, rs2270968, rs7479949 and rs4771268 were in line with those of our cohort. Our study replicated five novel functional SNPs in SNCA, MCCC1, DLG2, GBF1 and MBNL2 could be associated with increased risk of PD in southern Chinese population.

Circ0106714 inhibits tumorigenesis of colorectal cancer by sponging miR-942-5p and releasing DLG2 via Hippo-YAP signaling.

This study aimed to investigate the role of circ0106714-miR-942-5p-discs large homolog 2 (DLG2), a novel interactome, in colorectal cancer (CRC). Circ0106714 was found to be the most significantly downregulated circular RNA in CRC using a bioinformatics method, and we researched whether the ability of circ0106714 to sponge miR-942-5p and release DLG2 could affect CRC development via Hippo-YES-associated protein (YAP) signaling. We first employed qRT-PCR and immunoblotting to detect messenger RNA (mRNA) and protein expression, respectively. Live imaging of mice tumor xenografts was then conducted to study the effect of circ0106714 on tumor progression in vivo. Reporter gene assays were subsequently conducted to verify the predicted targeting relationship between circ0106714, miR-942-5p, and DLG2 mRNA in SW480 and HCT116 cell lines. As well as using flow cytometry for both apoptosis and cell cycle profile analyses, CCK-8 and clone foci formation assays were performed to assess cell survival. Wound healing assay and transwell invasion assay were later carried out to evaluate the migration and invasion of the cell lines. Findings revealed that circ0106714 and DLG2 were significantly downregulated, while miR-942-5p was significantly upregulated in human CRC tissues and cell lines. However, circ0106714 upregulation significantly suppressed tumor progression in vivo and inhibited the malignancy phenotypes of tumor cells in vitro by targeting miR-942-5p. Also discovered in this research was that miR-942-5p could directly target DLG2 mRNA, thus enhancing the malignancy phenotypes of CRC cells. We even found that DLG2 overexpression resulted in enhanced phosphorylation of YAP, a critical downstream effector of DLG2. This downstream effector was demonstrated to have a tumor-suppressive capacity in CRC cell lines. In sum, circ0106714 could suppress CRC by sponging miR-942-5p and releasing DLG2, thus promoting YAP phosphorylation.

DLG2 variants in patients with pubertal disorders.

PURPOSE: Impaired function of gonadotropin-releasing hormone (GnRH) neurons can cause a phenotypic spectrum ranging from delayed puberty to isolated hypogonadotropic hypogonadism (IHH). We sought to identify a new genetic etiology for these conditions. METHODS: Exome sequencing was performed in an extended family with autosomal dominant, markedly delayed puberty. The effects of the variant were studied in a GnRH neuronal cell line. Variants in the same gene were sought in a large cohort of individuals with IHH. RESULTS: We identified a rare missense variant (F900V) in DLG2 (which encodes PSD-93) that cosegregated with the delayed puberty. The variant decreased GnRH expression in vitro. PSD-93 is an anchoring protein of NMDA receptors, a type of glutamate receptor that has been implicated in the control of puberty in laboratory animals. The F900V variant impaired the interaction between PSD-93 and a known binding partner, Fyn, which phosphorylates NMDA receptors. Variants in DLG2 that also decreased GnRH expression were identified in three unrelated families with IHH. CONCLUSION: The findings indicate that variants in DLG2/PSD-93 cause autosomal dominant delayed puberty and may also contribute to IHH. The findings also suggest that the pathogenesis involves impaired NMDA receptor signaling and consequently decreased GnRH secretion.

Low DLG2 gene expression, a link between 11q-deleted and MYCN-amplified neuroblastoma, causes forced cell cycle progression, and predicts poor patient survival.

BACKGROUND: Neuroblastoma (NB) is a childhood neural crest tumor. There are two groups of aggressive NBs, one with MYCN amplification, and another with 11q chromosomal deletion; these chromosomal aberrations are generally mutually exclusive. The DLG2 gene resides in the 11q-deleted region, thus makes it an interesting NB candidate tumor suppressor gene. METHODS: We evaluated the association of DLG2 gene expression in NB with patient outcomes, stage and MYCN status, using online microarray data combining independent NB patient data sets. Functional studies were also conducted using NB cell models and the fruit fly. RESULTS: Using the array data we concluded that higher DLG2 expression was positively correlated to patient survival. We could also see that expression of DLG2 was inversely correlated with MYCN status and tumor stage. Cell proliferation was lowered in both 11q-normal and 11q-deleted NB cells after DLG2 over expression, and increased in 11q-normal NB cells after DLG2 silencing. Higher level of DLG2 increased the percentage of cells in the G2/M phase and decreased the percentage of cells in the G1 phase. We detected increased protein levels of Cyclin A and Cyclin B in fruit fly models either over expressing dMyc or with RNAi-silenced dmDLG, indicating that both events resulted in enhanced cell cycling. Induced MYCN expression in NB cells lowered DLG2 gene expression, which was confirmed in the fly; when dMyc was over expressed, the dmDLG protein level was lowered, indicating a link between Myc over expression and low dmDLG level. CONCLUSION: We conclude that low DLG2 expression level forces cell cycle progression, and that it predicts poor NB patient survival. The low DLG2 expression level could be caused by either MYCN-amplification or 11q-deletion. Video Abstract.

Identification of a novel Dlg2 isoform differentially expressed in IFNß-producing plasmacytoid dendritic cells.

BACKGROUND: The murine discs large homolog 2 (DLG2; post synaptic density 93 (PSD-93); Chapsyn-110) is a member of the membrane-associated guanylate kinase (MAGUK) protein family involved in receptor assembly and associated with signaling enzymes on cell membranes. In neurons, DLG2 protein isoforms derived from alternatively spliced transcripts have been described to bind to NMDA (N-methyl-aspartate) receptors and K channels and to mediate clustering of these channels in the postsynaptic membrane. In myeloid cells of the immune system, such as dendritic cells (DCs), a lack of data exists on the expression or function of DLG2. In cDNA microarray transcriptome analyses, we found Dlg2 highly expressed in a subpopulation of plasmacytoid DCs (pDCs) stimulated to produce type I interferons (IFNs) such as IFNß. RESULTS: Using RACE- and RT-PCR as well as immunoprecipitation followed by Western blotting we characterised the differential expression of the Dlg2 splice variants in IFNß-producing pDCs. Besides Dlg2É£ this cell population expressed a novel short Dlg2η transcript we termed Dlg2η3. Our expression data were integrated into information from genome databases to obtain a novel and comprehensive overview of the mouse Dlg2 gene architecture. To elucidate the intracellular localisation pattern of protein isoforms, ectopical expression analysis of fluorescently tagged DLG2 splice variants was performed. Here we found an enrichment of the larger isoform DLG2α1 at the plasma membrane while the newly identified shorter (DLG2η) isoform as well as DLG2É£ were equally distributed throughout the cytoplasm. Additionally, DLG2η was also found in the nucleus. Analysis of Dlg2-knockout mice previously generated by deleting exon 9 surprisingly revealed that the protein for the novel DLG2η isoform was still expressed in the brain and in bone marrow-derived pDCs from mice carrying the homozygous deletion (Dlg2 ΔE9/ΔE9 ). CONCLUSION: We describe a novel splice variant of the mouse Dlg2 gene termed Dlg2η and define the differential expression pattern of DLG2 isoforms in IFNß-producing pDCs. The presence of DLG2η protein in the CNS of Dlg2 ΔE9/ΔE9 mice might influence the phenotype of these mice and has to be taken into account in the interpretation of results regarding the functional role of DLG2 in neuronal postsynaptic membranes.

Genome-wide association study identifies novel susceptibility loci for migraine in Han Chinese resided in Taiwan.

Background Susceptibility genes for migraine, despite it being a highly prevalent and disabling neurological disorder, have not been analyzed in Asians by genome-wide association study (GWAS). Methods We conducted a two-stage case-control GWAS to identify susceptibility genes for migraine without aura in Han Chinese residing in Taiwan. In the discovery stage, we genotyped 1005 clinic-based Taiwanese migraine patients and 1053 population-based sex-matched controls using Axiom Genome-Wide CHB Array. In the replication stage, we genotyped 27 single-nucleotide polymorphisms with p < 10-4 in 1120 clinic-based migraine patients and 604 sex-matched normal controls by using Sequenom. Variants at LRP1, TRPM8, and PRDM, which have been replicated in Caucasians, were also genotyped. Results We identified a novel susceptibility locus (rs655484 in DLG2) that reached GWAS significance level for migraine risk in Han Chinese ( p = 1.45 × 10-12, odds ratio [OR] = 2.42), and also another locus (rs3781545in GFRA1) with suggestive significance ( p = 1.27 × 10-7, OR = 1.38). In addition, we observed positive association signals with a similar trend to the associations identified in Caucasian GWASs for rs10166942 in TRPM8 (OR = 1.33, 95% confidence interval [CI] = 1.14-1.54, Ppermutation = 9.99 × 10-5; risk allele: T) and rs1172113 in LRP1 (OR = 1.23, 95% CI = 1.04-1.45, Ppermutation = 2.9 × 10-2; risk allele: T). Conclusion The present study is the first migraine GWAS conducted in Han-Chinese and Asians. The newly identified susceptibility genes have potential implications in migraine pathogenesis. DLG2 is involved in glutamatergic neurotransmission, and GFRA1 encodes GDNF receptors that are abundant in CGRP-containing trigeminal neurons. Furthermore, positive association signals for TRPM8 and LRP1 suggest the possibility for common genetic contributions across ethnicities.

Mutations in the microtubule-associated protein 1A (Map1a) gene cause Purkinje cell degeneration.

The structural microtubule-associated proteins (MAPs) are critical for the organization of neuronal microtubules (MTs). Microtubule-associated protein 1A (MAP1A) is one of the most abundantly expressed MAPs in the mammalian brain. However, its in vivo function remains largely unknown. Here we describe a spontaneous mouse mutation, nm2719, which causes tremors, ataxia, and loss of cerebellar Purkinje neurons in aged homozygous mice. The nm2719 mutation disrupts the Map1a gene. We show that targeted deletion of mouse Map1a gene leads to similar neurodegenerative defects. Before neuron death, Map1a mutant Purkinje cells exhibited abnormal focal swellings of dendritic shafts and disruptions in axon initial segment (AIS) morphology. Furthermore, the MT network was reduced in the somatodendritic and AIS compartments, and both the heavy and light chains of MAP1B, another brain-enriched MAP, was aberrantly distributed in the soma and dendrites of mutant Purkinje cells. MAP1A has been reported to bind to the membrane-associated guanylate kinase (MAGUK) scaffolding proteins, as well as to MTs. Indeed, PSD-93, the MAGUK specifically enriched in Purkinje cells, was reduced in Map1a(-/-) Purkinje cells. These results demonstrate that MAP1A functions to maintain both the neuronal MT network and the level of PSD-93 in neurons of the mammalian brain.

Extracellular vesicles carrying miR-6836 derived from resistant tumor cells transfer cisplatin resistance of epithelial ovarian cancer via DLG2-YAP1 signaling pathway.

Background: Chemotherapy resistance is a significant cause for poor prognosis of epithelial ovarian cancer (EOC). However, the molecular mechanism of chemo-resistance remains unclear, and developing available therapies and effective biomarkers for resistant EOC is in urgent demand. Stemness of cancer cells directly results in chemo-resistance. Exosomal miRNAs rebuild tumor microenvironment (TME) and act as widely used clinical liquid biopsy markers. Methods: In our study, high throughput screenings and comprehensive analysis were performed to screen for miRNAs, which were both up-regulated in resistant EOC tissues and related to stemness, and miR-6836 was identified accordingly. Results: Clinically, high miR-6836 expression was closely correlated with poor chemotherapy response and survival for EOC patients. Functionally, miR-6836 promoted EOC cell cisplatin resistance by increasing stemness and suppressing apoptosis. Mechanistically, miR-6836 directly targeted DLG2 to enhance Yap1 nuclear translocation, and was regulated by TEAD1 forming the positive feedback loop: miR-6836-DLG2-Yap1-TEAD1. Furthermore, miR-6836 could be packaged into secreted exosomes in cisplatin-resistant EOC cells and exosomal miR-6836 was able to be delivered into cisplatin-sensitive EOC cells and reverse their cisplatin response. Conclusion: Our study revealed the molecular mechanisms of chemotherapy resistance, and identified miR-6836 as the possible therapeutic target and effective biopsy marker for resistant EOC.

Impaired reversal learning in the Dlg2+/- rat model of genetic risk for psychiatric disorder: Important questions regarding the neuro-behavioral mechanisms of reversal learning.

In this issue, Griesius et al report that heterozygous Dlg2+/- rats showed a reversal learning impairment on a specific bowl-digging task, whereas other reversal tasks were unaffected. The study suggests that Dlg2 gene disruption, which has been linked to neuropsychiatric disorders, including schizophrenia, may cause relatively specific impairments in reversal learning, an important aspect of cognitive flexibility. The study draws attention to two important issues regarding the neuro-behavioral mechanisms of reversal learning, namely that hippocampal dysfunction, which is prominent in Dlg2+/- rats, may contribute to reversal learning impairments and that, depending on the task and previous experience, brain and behavioral mechanisms of reversal learning may differ.

Inflammation suppresses DLG2 expression decreasing inflammasome formation.

PURPOSE: Loss of expression of DLG2 has been identified in a number of cancers to contribute to the disease by resulting in increased tumor cell proliferation and poor survival. In light of the previous evidence that DLG2 alters the cell cycle and affects proliferation, combined with indications that DLG2 is involved in NLRP3 inflammasome axis we speculated that DLG2 has an immune function. So far, there is no data that clearly elucidates this role, and this study was designed to investigate DLG2 in inflammatory colon disease and in colon cancer as well as its impact on inflammasome induction. METHODS: The DLG2 expression levels were established in publicly available inflammation, colon cancer and mouse model datasets. The overexpression and silencing of DLG2 in colon cancer cells were used to determine the effect of DLG2 expression on the activation of the inflammasome and subsequent cytokine release. RESULTS: The expression of DLG2 is repressed in inflammatory colon diseases IBD and Ulcerative colitis as well as colorectal cancer tissue compared to healthy individuals. We subsequently show that induction with inflammatory agents in cell and animal models results in a biphasic alteration of DLG2 with an initial increase followed by an ensuing decrease. DLG2 overexpression leads to a significant increase in expression of IL1B, IκBζ and BAX, components that result in inflammasome formation. DLG2 silencing in THP1 cells resulted in increased release of IL-6 into the microenvironment which once used to treat bystander COLO205 cells resulted in an increase in STAT3 phosphorylation and an increase proliferating cells and more cells in the G2/M phase. Restoration of DLG2 to the colon resulted in reduced AKT and S6 signaling. CONCLUSION: DLG2 expression is altered in response to inflammation in the gut as well as colon cancer, resulting in altered ability to form inflammasomes. TRIAL REGISTRATION: NCT03072641.

DLG2 impairs dsDNA break repair and maintains genome integrity in neuroblastoma.

BACKGROUND: In primary neuroblastoma, deletions on chromosome 11q are known to result in an increase in the total number of chromosomal breaks. The DNA double-strand break repair pathways mediated by NHEJ are often upregulated in cancer. DLG2, a candidate tumor suppressor gene on chromosome 11q, has previously been implicated in DNA repair. METHODS: We evaluated an association between gene expression and neuroblastoma patient outcome, risk categorization, and 11q status using publicly available microarray data from independent neuroblastoma patient datasets. Functional studies were conducted using comet assay and H2AX phosphorylation in neuroblastoma cell lines and in the fruit fly with UVC-induced DNA breaks. RESULTS: We show that the NHEJ genes PARP1 and FEN1 are over expressed in neuroblastoma and restoration of DLG2 impairs their gene and protein expression. When exposed to UVC radiation, cells with DLG2 over expression show less DNA fragmentation and induce apoptosis in a p53 S46 dependent manner. We could also confirm that DLG2 over expression results in CHK1 phosphorylation consistent with previous reports of G2/M maintenance. CONCLUSIONS: Taken together, we show that DLG2 over expression increases p53 mediated apoptosis in response to etoposide and UVC mediated genotoxicity and reduced DNA replication machinery.

Behavioural and molecular characterisation of the Dlg2 haploinsufficiency rat model of genetic risk for psychiatric disorder.

Genetic studies implicate disruption to the DLG2 gene in copy number variants as increasing risk for schizophrenia, autism spectrum disorders and intellectual disability. To investigate psychiatric endophenotypes associated with DLG2 haploinsufficiency (and concomitant PSD-93 protein reduction) a novel clinically relevant Dlg2+/- rat was assessed for abnormalities in anxiety, sensorimotor gating, hedonic reactions, social behaviour, and locomotor response to the N-Methyl-D-aspartic acid receptor antagonist phencyclidine. Dlg gene and protein expression were also investigated to assess model validity. Reductions in PSD-93 messenger RNA and protein were observed in the absence of compensation by other related genes or proteins. Behaviourally Dlg2+/- rats show a potentiated locomotor response to phencyclidine, as is typical of psychotic disorder models, in the absence of deficits in the other behavioural phenotypes assessed here. This shows that the behavioural effects of Dlg2 haploinsufficiency may specifically relate to psychosis vulnerability but are subtle, and partially dissimilar to behavioural deficits previously reported in Dlg2+/- mouse models demonstrating issues surrounding the comparison of models with different aetiology and species. Intact performance on many of the behavioural domains assessed here, such as anxiety and reward processing, will remove these as confounds when continuing investigation into this model using more complex cognitive tasks.

Actionable Genomics in Clinical Practice: Paradigmatic Case Reports of Clinical and Therapeutic Strategies Based upon Genetic Testing.

In clinical settings, the information provided by genetic testing can explain the triggers and processes underlying clinical presentations, such as neurodevelopmental disorders, in up to one third of affected individuals. However, translating this knowledge into better and more personalized clinical management to many appears a distant target. This article presents three paradigmatic cases to exemplify how this translational effort can, at least in some instances, be undertaken today with very positive results: (a) a young girl carrying a chr. 16p11.2 duplication can be screened using targeted exams and undertake therapeutic/preventive interventions related to her genetic diagnosis; (b) a 13-year-old boy with intellectual disability and autism spectrum disorder carries a chr. 11q14.1 deletion, partly spanning the DLG2 gene important for synaptic function, and gained over 20 I.Q. points ostensibly due to carbolithium, prescribed in the absence of affective symptoms, exclusively following the pathophysiology pointed out by the genetic results; (c) a 58-year-old woman carries a COL3A1 gene variant responsible for the vascular form of Ehler-Danlos syndrome with colon rupture. Detection of this variant in six members of her extended family allows for better clinical management of the proband and targeted genetic counselling for family members at risk of this connective tissue disorder. The unprecedented flow of genetic information available today through new technologies, if interpreted in the light of current knowledge in clinical diagnosis and care of those with connective tissue disorders and neurodevelopmental disturbances, in biology and in neuropsychopharmacology, can promote better clinical and pharmacological treatment, disease surveillance, and management provided and incorporated into the clinical setting.

DLG2 Mutations in the Etiology of Pubertal Delay and Idiopathic Hypogonadotropic Hypogonadism.

INTRODUCTION: Idiopathic hypogonadotropic hypogonadism (IHH) is caused by dysfunction of the hypothalamic-pituitary-gonadal axis. DLG2 was recently implicated as a gene associated with delayed puberty and which may also contribute to IHH. The confirmation of the candidate puberty genes in independent IHH cohorts has become crucial due to the lack of proper genotype-phenotype segregations in reported pedigrees. Therefore, we aimed to screen DLG2 in patient variants in a large cohort of IHH patients. METHODS: The present study included a total of 336 IHH patients from 290 independent families. The coding and flanking regions of DLG2 were screened for potentially important variants in the WES data. Candidate variants were evaluated in the -gnomAD and GME databases according to their allele frequencies, and only those with a frequency <0.0001 were considered rare. Detected variants were classified according to the ACMG/AMP criteria. RESULTS: We found 1 homozygous and 2 heterozygous missense variants in 3 independent pedigrees. Identified variants were found extremely rare or not reported in gnomAD. Two variants were categorized as "uncertain significance," and the other one was "likely pathogenic" according to the ACMG criteria. All patients were normosmic, and in 2 of the 3 families, there were no causal variants in other IHH-related genes. CONCLUSION: We detected 3 rare sequencing variants in DLG2 in 5 patients with IHH or delayed puberty in a large IHH cohort. Our results support the contention that the DLG2 mutations are associated with IHH in human puberty.

Chromosome Imbalances in Neuroblastoma-Recent Molecular Insight into Chromosome 1p-deletion, 2p-gain, and 11q-deletion Identifies New Friends and Foes for the Future.

Neuroblastoma is the most common extracranial solid pediatric tumor, with around 15% childhood cancer-related mortality. High-risk neuroblastomas exhibit a range of genetic, morphological, and clinical heterogeneities, which add complexity to diagnosis and treatment with existing modalities. Identification of novel therapies is a high priority in high-risk neuroblastoma, and the combination of genetic analysis with increased mechanistic understanding-including identification of key signaling and developmental events-provides optimism for the future. This focused review highlights several recent findings concerning chromosomes 1p, 2p, and 11q, which link genetic aberrations with aberrant molecular signaling output. These novel molecular insights contribute important knowledge towards more effective treatment strategies for neuroblastoma.

The palmitoyl acyltransferase ZDHHC14 controls Kv1-family potassium channel clustering at the axon initial segment.

The palmitoyl acyltransferase (PAT) ZDHHC14 is highly expressed in the hippocampus and is the only PAT predicted to bind Type-I PDZ domain-containing proteins. However, ZDHHC14's neuronal roles are unknown. Here, we identify the PDZ domain-containing Membrane-associated Guanylate Kinase (MaGUK) PSD93 as a direct ZDHHC14 interactor and substrate. PSD93, but not other MaGUKs, localizes to the axon initial segment (AIS). Using lentiviral-mediated shRNA knockdown in rat hippocampal neurons, we find that ZDHHC14 controls palmitoylation and AIS clustering of PSD93 and also of Kv1 potassium channels, which directly bind PSD93. Neurodevelopmental expression of ZDHHC14 mirrors that of PSD93 and Kv1 channels and, consistent with ZDHHC14's importance for Kv1 channel clustering, loss of ZDHHC14 decreases outward currents and increases action potential firing in hippocampal neurons. To our knowledge, these findings identify the first neuronal roles and substrates for ZDHHC14 and reveal a previously unappreciated role for palmitoylation in control of neuronal excitability.