Search

BackgroundMalformations of cortical development (MCDs) have been reported in a subset of patients with pathogenic heterozygous variants inGRIN1orGRIN2B, genes which encode for subunits of the N-methyl-D-aspartate receptor (NMDAR). The aim of this study was to further define the phenotypic spectrum of NMDAR-related MCDs.MethodsWe report the clinical, radiological and molecular features of 7 new patients and review data on 18 previously reported individuals with NMDAR-related MCDs. Neuropathological findings for two individuals with heterozygous variants inGRIN1are presented. We report the clinical and neuropathological features of one additional individual with homozygous pathogenic variants inGRIN1.ResultsHeterozygous variants inGRIN1andGRIN2Bwere associated with overlapping severe clinical and imaging features, including global developmental delay, epilepsy, diffuse dysgyria, dysmorphic basal ganglia and hippocampi. Neuropathological examination in two fetuses with heterozygousGRIN1variants suggests that proliferation as well as radial and tangential neuronal migration are impaired. In addition, we show that neuronal migration is also impaired by homozygousGRIN1variants in an individual with microcephaly with simplified gyral pattern.ConclusionThese findings expand our understanding of the clinical and imaging features of the ‘NMDARopathy’ spectrum and contribute to our understanding of the likely underlying pathogenic mechanisms leading to MCD in these patients.

Significant progress has been made in wireless Joint Source-Channel Coding (JSCC) using deep learning techniques. The latest DL-based image JSCC methods have demonstrated exceptional performance across various signal-to-noise ratio (SNR) levels during transmission, while also avoiding cliff effects. However, current channel adaptive JSCC methods rely heavily on channel prior knowledge, which can lead to performance degradation in practical applications due to channel mismatch effects. This paper proposes a novel approach for image transmission, called Channel Blind Joint Source-Channel Coding (CBJSCC). CBJSCC utilizes Deep Learning techniques to achieve exceptional performance across various signal-to-noise ratio (SNR) levels during transmission, without relying on channel prior information. We have designed an Inverted Residual Attention Bottleneck (IRAB) module for the model, which can effectively reduce the number of parameters while expanding the receptive field. In addition, we have incorporated a convolution and self-attention mixed encoding module to establish long-range dependency relationships between channel symbols. Our experiments have shown that CBJSCC outperforms existing channel adaptive DL-based JSCC methods that rely on feedback information. Furthermore, we found that channel estimation does not significantly benefit CBJSCC, which provides insights for the future design of DL-based JSCC methods. The reliability of the proposed method is further demonstrated through an analysis of the model bottleneck and its adaptability to different domains, as shown by our experiments.

Malformations of cortical development (MCDs) have been reported in a subset of patients with pathogenic heterozygous variants inWe report the clinical, radiological and molecular features of 7 new patients and review data on 18 previously reported individuals with NMDAR-related MCDs. Neuropathological findings for two individuals with heterozygous variants inHeterozygous variants inThese findings expand our understanding of the clinical and imaging features of the 'NMDARopathy' spectrum and contribute to our understanding of the likely underlying pathogenic mechanisms leading to MCD in these patients.

β-Glucan exhibits many biological activities and functions such as stimulation of the immune system and anti-inflammatory, anti-microbial, anti-infective, anti-viral, anti-tumor, anti-oxidant, anti-coagulant, cholesterol-lowering, radio protective, and wound healing effects. It has a wide variety of uses in pharmaceutical, cosmetic, and chemical industries as well as in food processing units. However, due to its dense triple helix structure, formed by the interaction of polyhydroxy groups in the β-d-glucan molecule, it features poor solubility, which not only constrains its applications, but also inhibits its physiological function in vivo. One aim is to expand the applications for modified β-glucan with potential to prevent disease, various therapeutic purposes and as health-improving ingredients in functional foods and cosmetics. This review introduces the major modification methods required to understand the bioactivity of β-glucan and critically provides a literature survey on the structural features of this molecule and reported biological activity. We also discuss a new method to create novel opportunities to exploit maximally various properties of β-glucan, namely ultrasound-assisted enzymatic modification.

Mutations in the GRIN2A gene, which encodes the GluN2A (glutamate [NMDA] receptor subunit epsilon-1) subunit of the N-methyl-d-aspartate receptor, have been identified in patients with epilepsy-aphasia spectrum disorders, idiopathic focal epilepsies with centrotemporal spikes, and epileptic encephalopathies with severe developmental delay. However, thus far, mutations in this gene have not been associated with a nonepileptic neurodevelopmental disorder with dystonia.The objective of this study was to identify the disease-causing gene in 2 siblings with neurodevelopmental and movement disorders with no epileptiform abnormalities.The study method was targeted next-generation sequencing panel for neuropediatric disorders and subsequent electrophysiological studies.The 2 siblings carry a novel missense mutation in the GRIN2A gene (p.Ala643Asp) that was not detected in genomic DNA isolated from blood cells of their parents, suggesting that the mutation is the consequence of germinal mosaicism in 1 progenitor. In functional studies, the GluN2A-A643D mutation increased the potency of the agonists L-glutamate and glycine and decreased the potency of endogenous negative modulators, including protons, magnesium and zinc but reduced agonist-evoked peak current response in mammalian cells, suggesting that this mutation has a mixed effect on N-methyl-d-aspartate receptor function.De novo GRIN2A mutations can give rise to a neurodevelopmental and movement disorder without epilepsy. © 2018 International Parkinson and Movement Disorder Society.

Mutations in the GRIN2A gene, which encodes the GluN2A (glutamate [NMDA] receptor subunit epsilon-1) subunit of the N-methyl-d-aspartate receptor, have been identified in patients with epilepsy-aphasia spectrum disorders, idiopathic focal epilepsies with centrotemporal spikes, and epileptic encephalopathies with severe developmental delay. However, thus far, mutations in this gene have not been associated with a nonepileptic neurodevelopmental disorder with dystonia.

ObjectiveEarly-onset epileptic encephalopathies have been associated with de novo mutations of numerous ion channel genes. We employed techniques of modern translational medicine to identify a disease-causing mutation, analyze its altered behavior, and screen for therapeutic compounds to treat the proband.MethodsThree modern translational medicine tools were utilized: 1) high-throughput sequencing technology to identify a novel de novo mutation; 2) in vitro expression and electrophysiology assays to confirm the variant protein's dysfunction; and 3) screening of existing drug libraries to identify potential therapeutic compounds.ResultsA de novo GRIN2A missense mutation (c.2434C>A; p.L812M) increased the charge transfer mediated by NMDA receptors containing the mutant GluN2A-L812M subunit. In vitro analysis with NMDA receptor blockers indicated that GLuN2A-L812M-containing NMDARs retained their sensitivity to the use-dependent channel blocker memantine; while screening of a previously reported GRIN2A mutation (N615K) with these compounds produced contrasting results. Consistent with these data, adjunct memantine therapy reduced our proband's seizure burden.InterpretationThis case exemplifies the potential for personalized genomics and therapeutics to be utilized for the early diagnosis and treatment of infantile-onset neurological disease.

NMDA receptors comprised of different NR2 subunits exhibit strikingly unique biophysical and pharmacological properties. Here, we report that the extracellular amino-terminal domain (ATD) of the NR2 subunit controls pharmacological and kinetic properties of recombinant NMDA receptors, such as agonist potency, deactivation time course, open probability (P(OPEN)), and mean open/shut duration. Using ATD deletion mutants of NR2A, NR2B, NR2C, NR2D, and chimeras of NR2A and NR2D with interchanged ATD [NR2A-(2D-ATD) and NR2D-(2A-ATD)], we show that the ATD contributes to the low glutamate potency of NR2A-containing NMDA receptors and the high glutamate potency of NR2D-containing receptors. The ATD influences the deactivation time courses of NMDA receptors, as removal of the ATD from NR2A slows the deactivation rate, while removal of the ATD from NR2B, NR2C and NR2D accelerates the deactivation rate. Open probability also is influenced by the ATD. Removal of the ATD from NR2A or replacement of the NR2A-ATD with that of NR2D decreases P(OPEN) in single-channel recordings from outside-out patches of HEK 293 cells. In contrast, deletion of the ATD from NR2D or replacement of the NR2D ATD with that of NR2A increases P(OPEN) and mean open duration. These data demonstrate the modular nature of NMDA receptors, and show that the ATD of the different NR2 subunits plays an important role in fine-tuning the functional properties of the individual NMDA receptor subtypes.