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1.
Small ; : e2312091, 2024 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-38308418

RESUMEN

Grafted biopolymer binders are demonstrated to improve the processability and cycling stability of the silicon (Si) nanoparticle anodes. However, there is little systematical exploration regarding the relationship between grafting density and performance of grafted binder for Si anodes, especially when Si particles exceed the critical breaking size. Herein, a series of guar gum grafted polyacrylamide (GP) binders with different grafting densities are designed and prepared to determine the optimal grafting density for maximizing the electrochemical performance of Si submicroparticle (SiSMP) anodes. Among various GP binders, GP5 with recommended grafting density demonstrates the strongest adhesion strength, best mechanical properties, and highest intrinsic ionic conductivity. These characteristics enable the SiSMP electrodes to sustain the electrode integrity and accelerate lithium-ion transport kinetics during cycling, resulting in high capacity and stable cyclability. The superior role of GP5 binder in enabling robust structure and stable interface of SiSMP electrodes is revealed through the PeakForce atomic force microscopy and in situ differential electrochemical mass spectrometry. Furthermore, the stable cyclabilities of high-loading SiSMP@GP5 electrode with ultralow GP5 content (1 wt%) at high areal capacity as well as the good cyclability of Ah-level LiNi0.8 Co0.1 Mn0.1 O2 /SiSMP@GP5 pouch cell strongly confirms the practical viability of the GP5 binder.

2.
J Neurol ; 271(5): 2560-2572, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38289536

RESUMEN

OBJECTIVES: To investigate the facial scan patterns during emotion recognition (ER) through the dynamic facial expression task and the awareness of social interference test (TASIT) using eye tracking (ET) technology, and to find some ET indicators that can accurately depict the ER process, which is a beneficial supplement to existing ER assessment tools. METHOD: Ninety-six patients with TLE and 88 healthy controls (HCs) were recruited. All participants watched the dynamic facial expression task and TASIT including a synchronized eye movement recording and recognized the emotion (anger, disgust, happiness, or sadness). The accuracy of ER was recorded. The first fixation time, first fixation duration, dwell time, and fixation count were selected and analyzed. RESULTS: TLE patients exhibited ER impairment especially for disgust (Z = - 3.391; p = 0.001) and sadness (Z = - 3.145; p = 0.002). TLE patients fixated less on the face, as evidenced by the reduced fixation count (Z = - 2.549; p = 0.011) of the face and a significant decrease in the fixation count rate (Z = - 1.993; p = 0.046). During the dynamic facial expression task, TLE patients focused less on the eyes, as evidenced by the decreased first fixation duration (Z = - 4.322; p = 0.000), dwell time (Z = - 4.083; p = 0.000), and fixation count (Z = - 3.699; p = 0.000) of the eyes. CONCLUSION: TLE patients had ER impairment, especially regarding negative emotions, which may be attributable to their reduced fixation on the eyes during ER, and the increased fixation on the mouth could be a compensatory effect to improve ER performance. Eye-tracking technology could provide the process indicators of ER, and is a valuable supplement to traditional ER assessment tasks.


Asunto(s)
Emociones , Epilepsia del Lóbulo Temporal , Tecnología de Seguimiento Ocular , Expresión Facial , Fijación Ocular , Humanos , Masculino , Femenino , Adulto , Fijación Ocular/fisiología , Emociones/fisiología , Epilepsia del Lóbulo Temporal/fisiopatología , Epilepsia del Lóbulo Temporal/psicología , Persona de Mediana Edad , Reconocimiento Facial/fisiología , Adulto Joven
3.
J Neurochem ; 2023 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-37649269

RESUMEN

N-methyl-D-aspartate receptors (NMDAR), ionotropic glutamate receptors, mediate a slow component of excitatory synaptic transmission in the central nervous system and play a key role in normal brain function and development. Genetic variations in GRIN genes encoding NMDAR subunits that alter the receptor's functional characteristics are associated with a wide range of neurological and neuropsychiatric conditions. Pathological GRIN variants located in the M2 re-entrant loop lining the channel pore cause significant functional changes, the most consequential alteration being a reduction in voltage-dependent Mg2+ inhibition. Voltage-dependent Mg2+ block is a unique feature of NMDAR biology whereby channel activation requires both ligand binding and postsynaptic membrane depolarization. Thus, loss of NMDAR Mg2+ block will have a profound impact on synaptic function and plasticity. Here, we choose 11 missense variants within the GRIN1, GRIN2A, and GRIN2B genes that alter residues located in the M2 loop and significantly reduce Mg2+ inhibition. Each variant was evaluated for tolerance to genetic variation using the 3-dimensional structure and assessed for functional rescue pharmacology via electrophysiological recordings. Three FDA-approved NMDAR drugs-memantine, dextromethorphan, and ketamine-were chosen based on their ability to bind near the M2 re-entrant loop, potentially rectifying dysregulated NMDAR function by supplementing the reduced voltage-dependent Mg2+ block. These results provide insight of structural determinants of FDA-approved NMDAR drugs at their binding sites in the channel pore and may further define conditions necessary for the use of such agents as potential rescue pharmacology.

4.
Neurol Sci ; 44(9): 3363-3368, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36988728

RESUMEN

BACKGROUND: POLR3-related leukodystrophy is a group of rare neurodegenerative disorders characterized by degeneration of the white matter with different combinations of major clinical features. CASE: An 18-year-old lady was admitted for no menstruation since childhood. She gradually developed slight symptoms, such as choking after drinking water and unsteady walking in the last 2 years. Furthermore, her test scores and response capability were far lower than that of her peers. Physical examination revealed her to be of a slightly short stature, with stiff expressions and bilateral breast enlargement. She revealed clumsy movements when examined for ataxia, with an SARA score of 9. FINDINGS: The laboratory data revealed a decreased level of estradiol, FSH, and LH, with a MoCA score of 7. Conventional karyotype analysis revealed a 46 XX 9qh + karyotype. Ultrasound indicated primordial uterus (19 × 11 × 10 mm). Brain MRI showed bilateral cerebral hemisphere myelin dysplasia, brain atrophy, thin corpus callosum, and small pituitary gland with uneven reinforcement and enlarged ventricles. Exome sequencing exhibited two missense mutations in the POLR3A gene (c.3013C > T and c.1757C > T), which were inherited from her mother and father, respectively. CONCLUSION: Collectively, we identified novel compound heterozygous mutations of the POLR3A gene that caused POLR3A-related hypomyelinating leukodystrophy with hypogonadism in the patient combined with the clinical presentation, MRI brain pattern, and medical exome sequencing. TEACHING POINTS: The complexity of clinical phenotypes and heterogeneity of genotypes raise new challenges in genetic diagnoses. This study will further aid our understanding of POLR3A-related leukodystrophy and promote further analysis of phenotype-genotype correlations of related diseases.


Asunto(s)
Enfermedades Desmielinizantes , Enfermedades Desmielinizantes del Sistema Nervioso Central Hereditarias , Humanos , Femenino , Enfermedades Desmielinizantes del Sistema Nervioso Central Hereditarias/diagnóstico por imagen , Enfermedades Desmielinizantes del Sistema Nervioso Central Hereditarias/genética , Mutación , Pueblos del Este de Asia , Mutación Missense , ARN Polimerasa III/genética
5.
Cell Mol Life Sci ; 80(2): 42, 2023 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-36645496

RESUMEN

N-methyl-D-aspartate receptors (NMDARs) play vital roles in normal brain functions (i.e., learning, memory, and neuronal development) and various neuropathological conditions, such as epilepsy, autism, Parkinson's disease, Alzheimer's disease, and traumatic brain injury. Endogenous neuroactive steroids such as 24(S)-hydroxycholesterol (24(S)-HC) have been shown to influence NMDAR activity, and positive allosteric modulators (PAMs) derived from 24(S)-hydroxycholesterol scaffold can also enhance NMDAR function. This study describes the structural determinants and mechanism of action for 24(S)-hydroxycholesterol and two novel synthetic analogs (SGE-550 and SGE-301) on NMDAR function. We also show that these agents can mitigate the altered function caused by a set of loss-of-function missense variants in NMDAR GluN subunit-encoding GRIN genes associated with neurological and neuropsychiatric disorders. We anticipate that the evaluation of novel neuroactive steroid NMDAR PAMs may catalyze the development of new treatment strategies for GRIN-related neuropsychiatric conditions.


Asunto(s)
Enfermedad de Alzheimer , Enfermedades del Sistema Nervioso , Neuroesteroides , Humanos , Receptores de N-Metil-D-Aspartato/metabolismo , Neuroesteroides/farmacología , Neuroesteroides/uso terapéutico , Hidroxicolesteroles/farmacología , Hidroxicolesteroles/uso terapéutico , Enfermedades del Sistema Nervioso/tratamiento farmacológico , Enfermedades del Sistema Nervioso/genética , Enfermedad de Alzheimer/tratamiento farmacológico , Esteroides/farmacología , Regulación Alostérica/fisiología
6.
ACS Appl Mater Interfaces ; 14(51): 56910-56918, 2022 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-36515974

RESUMEN

The large volume expansion hinders the commercial application of silicon oxide (SiOx) anodes in lithium-ion batteries. Recent studies show that binders play a vital role in mitigating the volume change of SiOx electrodes. Herein, we introduce the small molecule tannic acid (TA) with high branching into the linear poly(acrylic acid) (PAA) binder for SiOx anodes. The three-dimensional (3D) crosslinked network with multiple hydrogen bonds is formed by the incorporation of abundant hydroxyl groups with unique carboxyl groups, which increases the interfacial adhesive strength with SiOx particles. As a consequence, SiOx electrodes based on the PAA-TA binder show an excellent cycling performance with a high specific capacity of 1025 mA h g-1 at 500 mA g-1 after 250 cycles. Moreover, the SiOx||NCM811 full cell exhibits a reversible capacity of 143 mA h g-1 corresponding to 87.4% capacity retention after 100 cycles.

7.
Artículo en Inglés | MEDLINE | ID: mdl-36314536

RESUMEN

Micron-sized silicon oxide (SiOx) has been regarded as a promising anode material for new-generation lithium-ion batteries due to its high capacity and low cost. However, the distinct volume expansion during the repeated (de)lithiation process and poor conductivity can lead to structural collapse of the electrode and capacity fading. In this study, SiOx anode materials coated with TiO0.6N0.4 layers are fabricated by a facile solvothermal and thermal reduction technique. The TiO0.6N0.4 layers are homogeneously dispersed on SiOx particles and form an intimate contact. The TiO0.6N0.4 layers can enhance the conductivity and suppress volume expansion of the SiOx anode, which facilitate ion/electron transport and maintain the integrity of the overall electrode structure. The as-prepared SiOx-TiON-200 composites demonstrate a high reversible capacity of 854 mAh g-1 at 0.5 A g-1 with a mass loading of 2.0 mg cm-2 after 250 cycles. This surface modification technique could be extended to other anodes with low conductivity and large volume expansion for lithium-ion batteries.

8.
Zhongguo Dang Dai Er Ke Za Zhi ; 24(4): 366-371, 2022 Apr 15.
Artículo en Chino | MEDLINE | ID: mdl-35527409

RESUMEN

OBJECTIVES: To investigate the influencing factors for the quality of bowel preparation before colonoscopy in children and the association of the interval from the last administration of laxative to the start of colonoscopy (shortly referred to as waiting time) with the quality of bowel preparation. METHODS: A retrospective analysis was performed for the children who were admitted to the Department of Gastroenterology, Children's Hospital of Nanjing Medical University, from January to November 2020, and received bowel preparation with polyethylene glycol electrolyte powder combined with diet control before colonoscopy. According to the score of Boston bowel preparation scale, they were divided into two groups: adequate bowel preparation group (n=337) and inadequate bowel preparation group (n=30). Related data were collected from the children in both groups, including general information, possible influencing factors for the quality of bowel preparation, adverse reactions associated with bowel preparation, duration of colonoscopy, and postoperative diagnosis. Univariate and multivariate analyses were used to explore the influencing factors for the quality of bowel preparation. RESULTS: The univariate analysis showed that age, body weight, and waiting time were associated with inadequate bowel preparation (P<0.05). The multivariate analysis showed that older age (OR=2.155, 95%CI: 1.087-4.273, P=0.028) and longer waiting time (OR=1.559, 95% CI: 1.191-2.041, P=0.001) were independent risk factors for inadequate bowel preparation. The receiver operating characteristic (ROC) curve analysis showed that the cut-off value of waiting time was 5.5 hours in determining whether bowel preparation was adequate or not, with a sensitivity of 90.0%, a specificity of 50.7%, and an area under the ROC curve of 0.708. After grouping based on waiting time, it was found that the incidence rate of inadequate bowel preparation in the ≥5.5 hours group was significantly higher than that in the <5.5 hours group [14.0% (27/193) vs 1.7% (3/174), P<0.001]. CONCLUSIONS: For children who use polyethylene glycol electrolyte powder combined with diet control for bowel preparation, older age is an independent risk factor for inadequate bowel preparation before colonoscopy, which may be associated with an insufficient dose of polyethylene glycol in older children. Longer waiting time is also an independent risk factor for inadequate bowel preparation, and it is recommended that the waiting time should not exceed 5.5 hours.


Asunto(s)
Catárticos , Colonoscopía , Niño , Dieta , Electrólitos , Humanos , Polietilenglicoles/efectos adversos , Polvos , Estudios Retrospectivos
9.
Front Cardiovasc Med ; 8: 714460, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34485412

RESUMEN

The neuromuscular adverse events of immune checkpoint inhibitor (ICI) treatment include myositis, polymyalgia rheumatica, myocarditis, and myasthenia syndrome. We report a 47-year old female presenting with external ophthalmoplegia, generalized muscle weakness, and third-degree atrioventricular block 4 weeks after toripalimab treatment for metastatic thymoma. Creatine kinase was elevated to 25,200 U/l and cardiac troponin I to 2.796 ng/ml. Autoantibody profiling shows positive anti-ryanodine receptor and anti-acetylcholine receptor antibodies and negative myositis specific antibodies. Repetitive nerve stimulation did not reveal decrement of compound muscle action potentials. Pulse methylprednisolone and immunoglobulin infusion, together with temporary pacemaker insertion normalized her muscle enzyme levels and cardiac rhythm. This is the first report of overlaping neuromuscular adverse event of toripalimab.

10.
Prion ; 15(1): 177-182, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34486485

RESUMEN

We report a case of genetic Creutzfeldt-Jakob disease (gCJD), which has a clinical phenotype that is highly similar to Fatal Family Insomnia (FFI) and has a triad of Wernicke-Korsakoff syndrome (WKs) at the developmental stage of the disease. The 51-year-old male complained of sleep disorder and imbalance who had visited five different hospitals before diagnosed. A neurological examination revealed a triad of symptoms characteristic for WKs such as gaze paresis, ataxia of limbs and trunk, and memory disturbances. The disturbances increased during the course of the disease, which led to the death of the patient 18 months after the appearance of the signs. Although the patient show negative in brain magnetic resonance imaging (MRI) and 14-3-3 protein of cerebrospinal fluid (CSF), he was finally diagnosed with gCJD disease by the human prion protein (PRNP) gene mutations.


Asunto(s)
Síndrome de Creutzfeldt-Jakob , Insomnio Familiar Fatal , Priones , Trastornos del Inicio y del Mantenimiento del Sueño , Síndrome de Creutzfeldt-Jakob/genética , Humanos , Insomnio Familiar Fatal/genética , Masculino , Persona de Mediana Edad , Fenotipo , Priones/genética
11.
Front Genet ; 12: 694312, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34413877

RESUMEN

N-Methyl-D-aspartate receptors (NMDARs) are highly expressed in brain and play important roles in neurodevelopment and various neuropathologic conditions. Here, we describe a new phenotype in an individual associated with a novel de novo deleterious variant in GRIN1 (c.1595C>A, p.Pro532His). The clinical phenotype is characterized with developmental encephalopathy, striking stimulus-sensitive myoclonus, and frontal lobe and frontal white matter hypoplasia, with no apparent seizures detected. NMDARs that contained the P532H within the glycine-binding domain of GluN1 with either the GluN2A or GluN2B subunits were evaluated for changes in their pharmacological and biophysical properties, which surprisingly revealed only modest changes in glycine potency but a significant decrease in glutamate potency, an increase in sensitivity to endogenous zinc inhibition, a decrease in response to maximally effective concentrations of agonists, a shortened synaptic-like response time course, a decreased channel open probability, and a reduced receptor cell surface expression. Molecule dynamics simulations suggested that the variant can lead to additional interactions across the dimer interface in the agonist-binding domains, resulting in a more open GluN2 agonist-binding domain cleft, which was also confirmed by single-molecule fluorescence resonance energy transfer measurements. Based on the functional deficits identified, several positive modulators were evaluated to explore potential rescue pharmacology.

12.
Circ Cardiovasc Imaging ; 14(4): e010953, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33832329

RESUMEN

BACKGROUND: Remnant cholesterol makes great contribution to residual risk of cardiovascular disease, but population-based evidence on the relationship between remnant cholesterol and atherosclerosis is rare. Common carotid artery intima-media thickness (cIMT) is an imaging marker of subclinical atherosclerosis. We aimed to explore the association between remnant cholesterol levels and cIMT in patients with ischemic stroke. METHODS: One thousand four hundred ninety-six ischemic stroke patients with baseline serum lipids and carotid artery imaging data were included in this analysis. Fasting remnant cholesterol was calculated as total cholesterol minus HDL (high-density lipoprotein) cholesterol minus LDL (low-density lipoprotein) cholesterol. Abnormal cIMT was defined as mean cIMT and maximum cIMT value ≥1 mm. Logistic regression and restricted cubic spline models were used to assess the relationships between remnant cholesterol levels and abnormal cIMT. RESULTS: The multivariable-adjusted odds ratios (95% CIs) for the highest versus lowest quartile of remnant cholesterol were 2.06 (1.46-2.91) for abnormal mean cIMT and 1.70 (1.23-2.35) for abnormal maximum cIMT. There were linear associations between remnant cholesterol levels and both abnormal mean cIMT (P for linearity, <0.001) and abnormal maximum cIMT (P for linearity, 0.003). Moreover, the remnant cholesterol-cIMT association remained significant in the subsample of patients with optimal LDL cholesterol levels (n=179). CONCLUSIONS: Elevated fasting remnant cholesterol levels were positively associated with mean cIMT and maximum cIMT in patients with ischemic stroke, even in patients with optimal LDL cholesterol levels. Future prospective studies are needed to verify our findings and to assess the effect of remnant cholesterol-lowering interventions in patients with ischemic stroke.


Asunto(s)
Isquemia Encefálica/diagnóstico , Arteria Carótida Común/diagnóstico por imagen , Grosor Intima-Media Carotídeo , Colesterol/sangre , Anciano , Biomarcadores/sangre , Isquemia Encefálica/sangre , Femenino , Estudios de Seguimiento , Humanos , Masculino , Estudios Retrospectivos , Factores de Riesgo , Ultrasonografía
13.
Stereotact Funct Neurosurg ; 99(1): 55-64, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33302280

RESUMEN

PURPOSE: Abnormal neurogenesis in the hippocampus after status epilepticus (SE) has been suggested as a key pathogeny of temporal lobe epilepsy. This study aimed to investigate the effect of deep brain stimulation of the anterior thalamic nucleus (ANT-DBS) on hippocampal neurogenesis in LiCl-pilocarpine-induced epileptic rats and to analyze its relationship with postoperative spontaneous recurrent seizures (SRS) and anxiety. METHOD: SE was induced by a systemic LiCl-pilocarpine injection in adult male rats. Rats in the DBS group underwent ANT-DBS immediately after successful SE induction. SRS was only recorded during the chronic stage. An elevated plus maze was used to evaluate the level of anxiety in rats 7, 28, and 60 days after SE onset. After the elevated plus-maze experiment, rats were sacrificed under anesthesia in order to evaluate hippocampal neurogenesis. Doublecortin (DCX) was used as a marker for neurogenesis. RESULTS: During the chronic stage, SRS in rats in the DBS group were significantly decreased. The level of anxiety was increased significantly in rats in the DBS group 28 days after SE, while no significant differences in anxiety levels were found 7 and 60 days after SE. The number of DCX-positive cells in the hippocampus was significantly increased 7 days after SE and was significantly decreased 60 days after SE in all rats in which SE was induced. However, the number of DCX-positive cells in the DBS group was significantly lower than that in the other groups 28 days after SE. CONCLUSIONS: ANT-DBS may suppress SRS and increase the postoperative anxiety of epileptic rats by influencing hippocampal neurogenesis.


Asunto(s)
Estimulación Encefálica Profunda/métodos , Epilepsia/fisiopatología , Hipocampo/fisiología , Cloruro de Litio/toxicidad , Neurogénesis/fisiología , Pilocarpina/toxicidad , Animales , Núcleos Talámicos Anteriores/efectos de los fármacos , Núcleos Talámicos Anteriores/fisiología , Estimulación Encefálica Profunda/efectos adversos , Proteína Doblecortina , Epilepsia/inducido químicamente , Epilepsia/terapia , Hipocampo/citología , Masculino , Neurogénesis/efectos de los fármacos , Ratas , Ratas Sprague-Dawley
14.
Front Neurol ; 11: 471, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32612568

RESUMEN

Autoimmune encephalitic syndromes include mutism, somnolence, movement disorder, and behavioral, or psychiatric symptoms. When paired with bilateral basal ganglia lesions on magnetic resonance imaging, these support the diagnosis of basal ganglia encephalitis (BGE). BGE is a rare but distinct entity of putative autoimmune etiology, with specific basal ganglia inflammation and acute movement disorders. A previous study identified dopamine-2 receptors (D2R) antibody to be positive in most BGE children, indicating that the D2R antibody may trigger the downstream pathological process in BGE patients. The highest levels of D2R are found in the striatum, the nucleus accumbens, and the olfactory tubercle. D2R antibody-positive BGE is widely reported in children. Here we present a 17-year-old girl with a typical clinical feature of basal ganglia encephalitis, who benefited from immune therapy.

15.
Neuropharmacology ; 177: 108247, 2020 10 15.
Artículo en Inglés | MEDLINE | ID: mdl-32712275

RESUMEN

N-methyl-d-aspartate receptors (NMDARs) mediate a slow component of excitatory synaptic transmission that plays important roles in normal brain function and development. A large number of disease-associated variants in the GRIN gene family encoding NMDAR GluN subunits have been identified in patients with various neurological and neuropsychiatric disorders. Many of these variants reduce the function of NMDARs by a range of different mechanisms, including reduced glutamate potency, reduced glycine potency, accelerated deactivation time course, decreased surface expression, and/or reduced open probability. We have evaluated whether three positive allosteric modulators of NMDAR receptor function (24(S)-hydroxycholesterol, pregnenolone sulfate, tobramycin) and three co-agonists (d-serine, l-serine, and d-cycloserine) can mitigate the diminished function of NMDARs harboring GRIN variants. We examined the effects of these modulators on NMDARs that contained 21 different loss-of-function variants in GRIN1, GRIN2A, or GRIN2B, identified in patients with epilepsy, intellectual disability, autism, and/or movement disorders. For all variants, some aspect of the reduced function was partially restored. Moreover, some variants showed enhanced sensitivity to positive allosteric modulators compared to wild type receptors. These results raise the possibility that enhancement of NMDAR function by positive allosteric modulators may be a useful therapeutic strategy.


Asunto(s)
Variación Genética/genética , Trastornos Mentales/genética , Proteínas del Tejido Nervioso/genética , Enfermedades del Sistema Nervioso/genética , Receptores de N-Metil-D-Aspartato/genética , Regulación Alostérica/efectos de los fármacos , Regulación Alostérica/fisiología , Animales , Relación Dosis-Respuesta a Droga , Sistemas de Liberación de Medicamentos/métodos , Femenino , Humanos , Mutación con Pérdida de Función/genética , Trastornos Mentales/tratamiento farmacológico , Trastornos Mentales/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Enfermedades del Sistema Nervioso/tratamiento farmacológico , Enfermedades del Sistema Nervioso/metabolismo , Pregnenolona/administración & dosificación , Estructura Secundaria de Proteína , Receptores de N-Metil-D-Aspartato/metabolismo , Serina/administración & dosificación , Tobramicina/administración & dosificación , Xenopus laevis
16.
Brain ; 143(7): 2039-2057, 2020 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-32577763

RESUMEN

NMDA receptors play crucial roles in excitatory synaptic transmission. Rare variants in GRIN2A encoding the GluN2A subunit are associated with a spectrum of disorders, ranging from mild speech and language delay to intractable neurodevelopmental disorders, including but not limited to developmental and epileptic encephalopathy. A de novo missense variant, p.Ser644Gly, was identified in a child with this disorder, and Grin2a knock-in mice were generated to model and extend understanding of this intractable childhood disease. Homozygous and heterozygous mutant mice exhibited altered hippocampal morphology at 2 weeks of age, and all homozygotes exhibited lethal tonic-clonic seizures by mid-third week. Heterozygous adults displayed susceptibility to induced generalized seizures, hyperactivity, repetitive and reduced anxiety behaviours, plus several unexpected features, including significant resistance to electrically-induced limbic seizures and to pentylenetetrazole induced tonic-clonic seizures. Multielectrode recordings of neuronal networks revealed hyperexcitability and altered bursting and synchronicity. In heterologous cells, mutant receptors had enhanced NMDA receptor agonist potency and slow deactivation following rapid removal of glutamate, as occurs at synapses. NMDA receptor-mediated synaptic currents in heterozygous hippocampal slices also showed a prolonged deactivation time course. Standard anti-epileptic drug monotherapy was ineffective in the patient. Introduction of NMDA receptor antagonists was correlated with a decrease in seizure burden. Chronic treatment of homozygous mouse pups with NMDA receptor antagonists significantly delayed the onset of lethal seizures but did not prevent them. These studies illustrate the power of using multiple experimental modalities to model and test therapies for severe neurodevelopmental disorders, while revealing significant biological complexities associated with GRIN2A developmental and epileptic encephalopathy.


Asunto(s)
Modelos Animales de Enfermedad , Epilepsia Generalizada/tratamiento farmacológico , Epilepsia Generalizada/genética , Antagonistas de Aminoácidos Excitadores/uso terapéutico , Receptores de N-Metil-D-Aspartato/genética , Animales , Dextrometorfano/uso terapéutico , Epilepsia Generalizada/patología , Técnicas de Sustitución del Gen , Humanos , Lactante , Masculino , Memantina/uso terapéutico , Ratones , Trastornos del Neurodesarrollo/genética , Trastornos del Neurodesarrollo/patología
17.
Neuropharmacology ; 176: 108117, 2020 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-32389749

RESUMEN

NMDA receptors are ligand-gated ion channels that mediate excitatory neurotransmission. Most native NMDA receptors are tetrameric assemblies of two glycine-binding GluN1 and two glutamate-binding GluN2 subunits. Co-assembly of the glycine-binding GluN1 with glycine-binding GluN3 subunits (GluN3A-B) creates glycine activated receptors that possess strikingly different functional and pharmacological properties compared to GluN1/GluN2 NMDA receptors. The role of GluN1/GluN3 receptors in neuronal function remains unknown, in part due to lack of pharmacological tools with which to explore their physiological roles. We have identified the negative allosteric modulator EU1180-438, which is selective for GluN1/GluN3 receptors over GluN1/GluN2 NMDA receptors, AMPA, and kainate receptors. EU1180-438 is also inactive at GABA, glycine, and P2X receptors, but displays inhibition of some nicotinic acetylcholine receptors. Furthermore, we demonstrate that EU1180-438 produces robust inhibition of glycine-activated current responses mediated by native GluN1/GluN3A receptors in hippocampal CA1 pyramidal neurons. EU1180-438 is a non-competitive antagonist with activity that is independent of membrane potential (i.e. voltage-independent), glycine concentration, and extracellular pH. Non-stationary fluctuation analysis of neuronal current responses provided an estimated weighted mean unitary conductance of 6.1 pS for GluN1/GluN3A channels, and showed that EU1180-438 has no effect on conductance. Site-directed mutagenesis suggests that structural determinants of EU1180-438 activity reside near a short pre-M1 helix that lies parallel to the plane of the membrane below the agonist binding domain. These findings demonstrate that structural differences between GluN3 and other glutamate receptor subunits can be exploited to generate subunit-selective ligands with utility in exploring the roles GluN3 in neuronal function.


Asunto(s)
Antagonistas de Aminoácidos Excitadores/farmacología , Proteínas del Tejido Nervioso/química , Proteínas del Tejido Nervioso/metabolismo , Receptores de N-Metil-D-Aspartato/química , Receptores de N-Metil-D-Aspartato/metabolismo , Regulación Alostérica/efectos de los fármacos , Regulación Alostérica/fisiología , Animales , Relación Dosis-Respuesta a Droga , Agonistas de Aminoácidos Excitadores/farmacología , Femenino , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Humanos , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Proteínas del Tejido Nervioso/agonistas , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Técnicas de Cultivo de Órganos , Unión Proteica/efectos de los fármacos , Unión Proteica/fisiología , Estructura Secundaria de Proteína , Receptores de N-Metil-D-Aspartato/agonistas , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Xenopus laevis
18.
Front Neurol ; 11: 602000, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33633657

RESUMEN

Purpose: To evaluate the attitudes toward epilepsy among parents of children with epilepsy (CWE) in China and identify some related factors for future interventions for parents to offer more social support for CWE. Method: The Chinese Public Attitudes Toward Epilepsy (CPATE) scale was administered to 234 parents of CWE and 203 parents of normal children in Xiangya hospital during 2019-2020. Results: The cumulative score of the parents of CWE (26.427 ± 6.688) was significantly lower than that of the normal children group (32.330 ± 7.234, p < 0.001). Subanalysis showed more positive attitudes among parents of CWE than the control group (p < 0.001) toward education (4.765 ± 1.985 vs. 6.621 ± 2.419), social life (6.556 ± 2.456 vs. 8.010 ± 2.683), marriage (9.586 ± 2.675 vs. 11.025 ± 2.900), and employment (3.876 ± 1.364 vs. 4.5123 ± 1.283). The attitudes toward epilepsy among parents of CWE with seizures in public (27.16 ± 6.66) or during sleep (27.10 ± 6.38) were more negative than those without (25.35 ± 6.62 and 25.08 ± 7.10, respectively) (p < 0.05). In addition, female and low income were negatively related to parents' attitudes toward epilepsy. Conclusions: More active policy guidance and adequate social support should be given to parents of children with seizures in public or during sleep to instruct their children to form a positive perception about epilepsy, which is expected to have a positive impact on their social abilities in the future.

19.
Hum Mutat ; 40(12): 2393-2413, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31429998

RESUMEN

N-methyl-D-aspartate receptors (NMDARs) mediate slow excitatory postsynaptic transmission in the central nervous system, thereby exerting a critical role in neuronal development and brain function. Rare genetic variants in the GRIN genes encoding NMDAR subunits segregated with neurological disorders. Here, we summarize the clinical presentations for 18 patients harboring 12 de novo missense variants in GRIN1, GRIN2A, and GRIN2B that alter residues in the M2 re-entrant loop, a region that lines the pore and is intolerant to missense variation. These de novo variants were identified in children with a set of neurological and neuropsychiatric conditions. Evaluation of the receptor cell surface expression, pharmacological properties, and biophysical characteristics show that these variants can have modest changes in agonist potency, proton inhibition, and surface expression. However, voltage-dependent magnesium inhibition is significantly reduced in all variants. The NMDARs hosting a single copy of a mutant subunit showed a dominant reduction in magnesium inhibition for some variants. These variant NMDARs also show reduced calcium permeability and single-channel conductance, as well as altered open probability. The data suggest that M2 missense variants increase NMDAR charge transfer in addition to varied and complex influences on NMDAR functional properties, which may underlie the patients' phenotypes.


Asunto(s)
Mutación Missense , Proteínas del Tejido Nervioso/genética , Enfermedades del Sistema Nervioso/genética , Receptores de N-Metil-D-Aspartato/genética , Animales , Niño , Modelos Animales de Enfermedad , Femenino , Células HEK293 , Humanos , Masculino , Modelos Moleculares , Proteínas del Tejido Nervioso/química , Fenotipo , Conformación Proteica , Receptores de N-Metil-D-Aspartato/química , Xenopus laevis
20.
ACS Chem Neurosci ; 10(5): 2263-2275, 2019 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-30698943

RESUMEN

GluN2B is the most studied subunit of N-methyl-d-aspartate receptors (NMDARs) and implicated in the pathologies of various central nervous system disorders and neurodegenerative diseases. As pan NMDAR antagonists often produce debilitating side effects, new approaches in drug discovery have shifted to subtype-selective NMDAR modulators, especially GluN2B-selective antagonists. While positron emission tomography (PET) studies of GluN2B-selective NMDARs in the living brain would enable target engagement in drug development and improve our understanding in the NMDAR signaling pathways between normal and disease conditions, a suitable PET ligand is yet to be identified. Herein we developed an 18F-labeled potent antagonist, 2-((1-(4-[18F]fluoro-3-methylphenyl)-1 H-1,2,3-triazol-4-yl)methoxy)-5-methoxypyrimidine ([18F]13; also called [18F]N2B-0518) as a PET tracer for imaging the GluN2B subunit. The radiofluorination of [18F]13 was efficiently achieved by our spirocyclic iodonium ylide (SCIDY) method. In in vitro autoradiography studies, [18F]13 displayed highly region-specific binding in brain sections of rat and nonhuman primate, which was in accordance with the expression of GluN2B subunit. Ex vivo biodistribution in mice revealed that [18F]13 could penetrate the blood-brain barrier with moderate brain uptake (3.60% ID/g at 2 min) and rapid washout. Altogether, this work provides a GluN2B-selective PET tracer bearing a new chemical scaffold and shows high specificity to GluN2B subunit in vitro, which may pave the way for the development of a new generation of GluN2B PET ligands.


Asunto(s)
Encéfalo/diagnóstico por imagen , Tomografía de Emisión de Positrones/métodos , Receptores de N-Metil-D-Aspartato/metabolismo , Triazoles , Animales , Autorradiografía , Encéfalo/metabolismo , Radioisótopos de Flúor , Radiofármacos , Ratas
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