NMDAR PAMs: Multiple Chemotypes for Multiple Binding Sites

CPEB3 can regulate seizure susceptibility by inhibiting the transcriptional activity of STAT3 on NMDARs expression

BACKGROUND

The pathogenesis of epilepsy is complex, and current antiepileptic drugs do not effectively control the seizures. Cytoplasmic polyadenylation element-binding protein 3 (CPEB3) regulates neuronal excitability, but its mechanism of action in epilepsy is not clear. In this paper, we investigated the effect of CPEB3 on seizures and elucidated its underlying molecular mechanism.

METHODS

Bioinformatics-based search for genes closely associated with epilepsy. Changes in expression and cellular localization of CPEB3 in epilepsy were verified by western blotting (WB) and Immunofluorescence staining. Subsequently, The adeno-associated virus was employed to overexpress or knockdown in mice. Behavioral experiments verified the effect of CPEB3 on epileptic phenotype, and the molecular mechanism of CPEB3 affecting epileptic phenotype was explored by WB, real-time quantitative polymerase chain reaction (RT-qPCR), RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (CHIP).

RESULTS

The results were that CPEB3 was downregulated epilepsy in model mice and patients with temporal lobe epilepsy and co-expressed with neurons. Behavioral experiments have shown that CPEB3 negatively regulates epilepsy phenotype in mice. In addition, exogenous CPEB3 can also bind to the mRNA of signal transducer and activator of transcription 3 (STAT3) and inhibit its translation, resulting in lower levels of STAT3 and p-STAT3, reduced nuclear translocation of STAT3, and decreased STAT3-mediated transcriptional activity of GluN1, GluN2A, and GluN2B, suppressing the expression of NMDAR subunits, which attenuate the seizure degree and susceptibility of epileptic mice.

CONCLUSION

These findings suggest that CPEB3 may influence excitability and susceptibility in epileptic mice by regulating STAT3 translation and transcriptional activities to promote NMDARs expression. This mechanism could offer insights into novel therapeutic targets for epilepsy.

The Role of Photobiomodulation to Modulate Ion Channels in the Nervous System: A Systematic Review

Photobiomodulation (PBM) is a safe and effective neurotherapy that modulates cellular pathways by altering cell membrane potentials, leading to beneficial biological effects such as anti-inflammatory and neuroregenerative responses. This review compiles studies from PubMed up to March 2024, investigating the impact of light at wavelengths ranging from 620 to 1270 nm on ion channels. Out of 330 articles screened, 19 met the inclusion criteria. Research indicates that PBM can directly affect various ion channels by influencing neurotransmitter synthesis in neighboring cells, impacting receptors like glutamate and acetylcholine, as well as potassium, sodium channels, and transient receptor potential channels. The diversity of studies hampers a comprehensive meta-analysis for evaluating treatment strategies effectively. This systematic review aims to explore the potential role of optoelectronic signal transduction in PBM, studying the neurobiological mechanisms and therapeutic significance of PBM on ion channels. However, the lack of uniformity in current treatment methods underscores the necessity of establishing standardized and reliable therapeutic approaches.

Acupuncture Alleviates Chronic Ischemic White Matter Injury in SHR Rats via JNK-NMDAR Circuit

To study the protective mechanism of acupuncture at "Jiangya Recipe" on chronic ischemic white matter injury in spontaneously hypertensive rats (SHR) and the regulation of Jun N-terminal kinase-N-methyl-D-aspartate receptor (JNK-NMDAR) loop. A hypertensive white matter injury model was established in 46 male SHR rats aged 11 weeks by bilateral common carotid artery tapering (SHR-2VGO). In the SHR sham operation group, only bilateral common carotid arteries were isolated and in the SHR-2VGO modeling group, 36 rats were used for microcoil spring clip implantation to narrow the common carotid arteries and then, after 2 weeks of modeling, rats with impaired motor function were removed, and SHR-2VGO rats with successful final models were randomly divided into the model group, JNK blocking group, and acupuncture group. The sham operation group, model group, and JNK blocking group underwent the same grasping fixation, and the acupuncture group received acupuncture at acupoints "Jiangya Fang" once daily. In the JNK blocker group, an injection cannula was implanted into the lateral ventricle and sp600125 was injected into the lateral ventricle at 4.5 ul/day for 4 weeks. One week after the end of the intervention, white matter lesions were detected by MRI DWI and T2 imaging, and the learning and memory ability of rats was tested by Y-Maze and Passive Avoidance. Myelin density was detected by luxol fast blue (LFB) staining, also axon arrangement, myelin integrity, and thickness of neurons were detected by electron microscopy; neuronal morphology and the number of Nissl bodies in the hippocampus were detected by Nissl staining, dendritic spine density changes were detected by Golgi staining, and JNK, NMDAR1, and N-methyl-D-receptor 2B (NMDAR2B) in DG, CA3 region of hippocampus were detected by immunohistochemistry, protein expression of p-JNK/JNK, p-NMDAR1/NMDAR1, NMDAR2B, GSK3β protein expression in the fimbria of hippocampus was detected by Western blot. The Y maze test of SHR-2VGO+Acu and SHR-2VGO+ sp600125 group showed that the spontaneous alternating reaction rate increased significantly. At the same time, the incubation period increased significantly and the number of errors decreased significantly in Passive Avoidance. MRI T2WI showed that the white matter high signal of the corpus callosum, internal capsule and hippocampal fimbria in the SHR-2VGO+ sp600125 and SHR-2VGO+Acu groups was significantly lower than that in the SHR-2VGO model group, and the striatum and anterior commissure were not obvious. DWI showed that the SHR-2VGO model group had scattered high signal and limited diffusion movement in both the internal capsule and striatum, but the difference between groups was not obvious. Compared with SHR-2VGO rats, LFB staining of SHR-2VGO + sp600125 and SHR-2VGO +Acu groups showed significant relaxation of myelin porosity in corpus callosum, striatum, inner capsule, anterior commissure and hippocampal fimbria, and electron microscopy showed improved axonal myelin integrity and thickness in corpus callosum region. Also, the number of blue patchy Nissl bodies increased, and the number and complexity of dendritic spines increased significantly in Golgi staining. Immunohistochemical detection showed that JNK levels in DG and CA3 region were increased and NMDAR1 and NMDAR2B levels were decreased in SHR-2VGO+Acu and SHR-2VGO+ sp600125 groups. Meanwhile, protein expressions of GSK3β, NMDAR1/p-NMDAR1 and NMDAR2B in fimbria of hippocampus were increased, and JNK/P-JNK protein expression decreased. Acupuncture can increase the density and thickness of myelin sheath in white matter areas of corpus callosum, anterior commissure and hippocampal fimbria, increase the number and length of hippocampal neuronal dendrites, and improve hypertensive white matter injury and cognitive decline through JNK-NMDAR pathway.

Discovery of GluN2A subtype-selective N-methyl-d-aspartate (NMDA) receptor ligands

The N-methyl-d-aspartate (NMDA) receptors, which belong to the ionotropic Glutamate receptors, constitute a family of ligand-gated ion channels. Within the various subtypes of NMDA receptors, the GluN1/2A subtype plays a significant role in central nervous system (CNS) disorders. The present article aims to provide a comprehensive review of ligands targeting GluN2A-containing NMDA receptors, encompassing negative allosteric modulators (NAMs), positive allosteric modulators (PAMs) and competitive antagonists. Moreover, the ligands' structure-activity relationships (SARs) and the binding models of representative ligands are also discussed, providing valuable insights for the clinical rational design of effective drugs targeting CNS diseases.

Risk Factors and Prognosis in Anti-NMDA Receptor Encephalitis Patients with Disturbance of Consciousness

Purpose

Disturbance of consciousness is common in patients with severe anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. However, little is known about it. This study aimed to analyze the clinical manifestations and prognostic factors of anti-NMDAR encephalitis with disturbance of consciousness.

Methods

In this retrospective study, the clinical features, treatment results, and long-term outcomes of anti-NMDAR encephalitis patients with disturbance of consciousness were analyzed, and multivariate logistic regression was used to analyze the factors affecting their prognosis.

Results

In the group with disturbance of consciousness, the incidences of seizures, involuntary movements, pulmonary infection, mechanical ventilation, intensive care unit (ICU) admission, neutrophil-lymphocyte ratio (NLR), abnormal cerebrospinal fluid index, plasma exchange, and immunosuppressive therapy were higher than those in the group without disturbance of consciousness (all P<0.05). During the follow-up period (median: 36 months, range: 12-78 months), the modified Rankin scale (mRS) score, the maximum mRS score during hospitalization, the mRS score at discharge, and the mRS score at 12 months after discharge were higher in the disturbance of consciousness group (all P < 0.001). However, there was no significant difference in long-term outcomes and recurrence between the two groups. Multivariate logistic regression analysis showed that mechanical ventilation, elevated IgG index, and delayed immunotherapy were independent risk factors for poor outcomes in patients with anti-NMDAR encephalitis with disturbance of consciousness at 12 months (odds ratio: 22.591, 39.868, 1.195). The receiver operating characteristics (ROC) curve analysis showed that the area under the curve (AUC) of mechanical ventilation, elevated IgG index, and delayed immunotherapy was 0.971 (95% CI=0.934-1.000, P<0.001).

Conclusion

Mechanical ventilation, elevated IgG index, and delayed immunotherapy may be the influencing factors of poor prognosis of anti-NMDAR encephalitis patients with disturbance of consciousness. Although their condition is relatively serious, most patients with anti-NMDAR encephalitis with disturbance of consciousness will achieve favorable long-term outcomes after long-term treatment.

Paroxysmal speech disorder as the initial symptom in a young adult with anti-N-methyl-D-aspartate receptor encephalitis: A case report

BACKGROUND

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a treatable but frequently misdiagnosed autoimmune disease. Speech dysfunction, as one of the common manifestations of anti-NMDAR encephalitis, is usually reported as a symptom secondary to psychiatric symptoms or seizures rather than the initial symptom in a paroxysmal form. We report a case of anti-NMDAR encephalitis with paroxysmal speech disorder as a rare initial manifestation, and hope that it will contribute to the literature.

CASE SUMMARY

A 39-year-old man with anti-NMDAR encephalitis initially presented with paroxysmal nonfluent aphasia and was misdiagnosed with a transient ischemic attack and cerebral infarction successively. The patient subsequently presented with seizures, but no abnormalities were found on brain magnetic resonance imaging or electroencephalogram. Cerebrospinal fluid (CSF) analysis revealed mild pleocytosis and increased protein levels. Anti-NMDAR antibodies in serum and CSF were detected for a conclusive diagnosis. After immunotherapy, the patient made a full recovery.

CONCLUSION

This case suggests that paroxysmal speech disorder may be the presenting symptom of anti-NMDAR encephalitis in a young patient.

Perillaldehyde improves cognitive function in vivo and in vitro by inhibiting neuronal damage via blocking TRPM2/NMDAR pathway

BACKGROUND

Vascular cognitive dysfunction in patients with vascular dementia (VD) is a kind of severe cognitive dysfunction syndrome caused by cerebrovascular diseases. At present, effective drugs to improve the cognitive function of VD patients still need to be explored. Transient Receptor Potential Melastatin 2 (TRPM2) channel is a nonspecific cation channel that plays a key role in the toxic death of neurons. Perillaldehyde (PAE) has the protective effect of epilepsy and insomnia and other central nervous system diseases. The aim of this study is to explore whether PAE improves cognitive function in VD rats and to investigate the potential mechanisms in vivo and vitro.

METHODS

VD rats were induced by bilateral common carotid arteries occlusion (2-vessel occlusion [2VO]) and treated with PAE for 4 weeks. The neuroprotective effects of PAE was subsequently assessed by the Morris water maze, hematoxylin-eosin (HE) staining, Golgi staining, electron microscopy, Neuron-specific nuclear protein (Neu N) staining, and TdT-mediated dUTP nick end labeling (TUNEL) staining. After primary hippocampal neurons were isolated, cell viability was detected by MTT assay and intracellular Ca²⁺ concentration was detected by calcium imaging assay. The content of Nitriteoxide (NO), Malondialdehyde (MDA) and Superoxide dismutase (SOD) activity in serum of rats were observed by Enzyme Linked Immunosorbent Assay (ELISA). Immunohistochemistry, Western blot, and Confocal laser scanning were used to detect the expression levels of N-methyl-D-asprtate receptor-2B (NR2B) and TRPM2.

RESULTS

The results showed that PAE can improve the number and activity of neurons, increase the length and number of dendrites in hippocampus, decrease the Vv value and PE value of neuronal nucleus and mitochondrial structure significantly, increase the s value and L value in nucleus structure, decrease the s value and L value in mitochondrial structure, and improve the learning and memory ability of rats significantly. And PAE can strengthen the ability of antioxidant stress confirmed by increasing the activity of SOD and reducing the production of MDA. The results of western blot, immunohistochemistry and immunofluorescence showed that PAE could reduce the level of TRPM2 and increase the expression of NR2B.

CONCLUSIONS

Taken together, our findings provide evidence that the neuroprotective effects of PAE in VD rats maybe through TRPM2 inhibition and subsequent activation of NMDAR signaling pathway.

Gastrodin Attenuates Tourette Syndrome by Regulating EAATs and NMDA Receptors in the Striatum of Rats

PURPOSE

This study explored whether gastrodin (Gas) could attenuate the symptoms of Tourette syndrome(TS) via the regulation of glutamate (Glu), its transporters (EAAT1 and EAAT2) and its receptors (NMDAR1, NMDAR2A and NMDAR2B) in rats.

MATERIALS AND METHODS

Seventy-five Wistar male rats were randomly divided into five groups (n=15 each): the control, TS, Tia (tiapride, 25mg/kg), Gas60 (gastrodin, 60mg/kg) and Gas120 groups (gastrodin, 120mg/kg). Rats in all groups except the control group received intraperitoneal injection of 3,3'-iminodipropionitrile (IDPN) for 7 consecutive days to establish the TS model. Thereafter, rats in the Tia, Gas60, and Gas120 groups were gavaged with 25mg/kg Tia, 60mg/kg Gas and 120mg/kg Gas for 28 days. Rats in the control and TS groups were gavaged with 0.9% normal saline. Behavioral evaluation was performed by using stereotypy scoring, nodding experiment and autonomic activity test. The Glu level was measured by UPLC-QqQ-MS analysis. The expression of EAAT1, EAAT2, NMDAR1, NMDAR2A and NMDAR2B was measured by Western blot and quantitative real-time PCR (qRT-PCR) analyses.

RESULTS

The results showed that rats with IDPN-induced TS exhibited an increase in stereotypy score, nodding numbers, number of times to enter the central area and autonomic total distance, which could be improved by Tia and Gas treatments. Furthermore, Tia and Gas treatments significantly decreased the IDPN-induced the increase in Glu levels in rats with TS. Furthermore, the decreased expression of EAAT1 and EAAT2 and increased expression of NMDAR1, NMDAR2A, and NMDAR2B in rats with TS induced by IDPN could be substantially altered by Tia and Gas treatments.

CONCLUSION

Gas ameliorated the behavioral dysfunction of rats with TS by maintaining Glu at a normal level, upregulating the expression of EAAT1 and EAAT2, and downregulating the expression of NMDAR1, NMDAR2A and NMDAR2B.

Obesity and Related Type 2 Diabetes: A Failure of the Autonomic Nervous System Controlling Gastrointestinal Function?

The pandemic spread of obesity and type 2 diabetes is a serious health problem that cannot be contained with common therapies. At present, the most effective therapeutic tool is metabolic surgery, which substantially modifies the gastrointestinal anatomical structure. This review reflects the state of the art research in obesity and type 2 diabetes, describing the probable reason for their spread, how the various brain sectors are involved (with particular emphasis on the role of the vagal system controlling different digestive functions), and the possible mechanisms for the effectiveness of bariatric surgery. According to the writer’s interpretation, the identification of drugs that can modulate the activity of some receptor subunits of the vagal neurons and energy-controlling structures of the central nervous system (CNS), and/or specific physical treatment of cortical areas, could reproduce, non-surgically, the positive effects of metabolic surgery.