Cell-specific NFIA upregulation promotes epileptogenesis by TRPV4-mediated astrocyte reactivity.

BACKGROUND: The astrocytes in the central nervous system (CNS) exhibit morphological and functional diversity in brain region-specific pattern. Functional alterations of reactive astrocytes are commonly present in human temporal lobe epilepsy (TLE) cases, meanwhile the neuroinflammation mediated by reactive astrocytes may advance the development of hippocampal epilepsy in animal models. Nuclear factor I-A (NFIA) may regulate astrocyte diversity in the adult brain. However, whether NFIA endows the astrocytes with regional specificity to be involved in epileptogenesis remains elusive. METHODS: Here, we utilize an interference RNA targeting NFIA to explore the characteristics of NFIA expression and its role in astrocyte reactivity in a 4-aminopyridine (4-AP)-induced seizure model in vivo and in vitro. Combined with the employment of a HA-tagged plasmid overexpressing NFIA, we further investigate the precise mechanisms how NIFA facilitates epileptogenesis. RESULTS: 4-AP-induced NFIA upregulation in hippocampal region is astrocyte-specific, and primarily promotes detrimental actions of reactive astrocyte. In line with this phenomenon, both NFIA and vanilloid transient receptor potential 4 (TRPV4) are upregulated in hippocampal astrocytes in human samples from the TLE surgical patients and mouse samples with intraperitoneal 4-AP. NFIA directly regulates mouse astrocytic TRPV4 expression while the quantity and the functional activity of TRPV4 are required for 4-AP-induced astrocyte reactivity and release of proinflammatory cytokines in the charge of NFIA upregulation. NFIA deficiency efficiently inhibits 4-AP-induced TRPV4 upregulation, weakens astrocytic calcium activity and specific astrocyte reactivity, thereby mitigating aberrant neuronal discharges and neuronal damage, and suppressing epileptic seizure. CONCLUSIONS: Our results uncover the critical role of NFIA in astrocyte reactivity and illustrate how epileptogenic brain injury initiates cell-specific signaling pathway to dictate the astrocyte responses.

COLQ-mutation congenital myasthenic syndrome in late adolescence: Case report and review of the literature.

Congenital myasthenia syndromes (CMS) are a heterogeneous group of hereditary disorders of the neuromuscular junction. The symptoms include fatigue, muscle weakness, ptosis, mastication or swallowing problem, respiratory distress. We present a 42-year-old male patient who was admitted with complaints of paroxysmal limb weakness for 25 years and got repeated apnea crisis due to using AchE inhibitors. We considered this patient to be COLQ-related CMS because of two types characteristics. One is the symptom will deteriorate or non-responsive after giving AchE inhibitors and the other is repeated compound action potentials may appear after one current stimulation. At last we confirmed the diagnosis by genetic testing. It is a rare CMS case caused by homozygous mutation in the COLQ gene which occurred at late adolescence. Our case demonstrates that for those serum-negative MG patients, CMS gene mutation screening should be considered, especially if the patient has an symptom onset of childhood and adolescence.

Effect of Transcranial Direct Current Stimulation on Patients With Disorders of Consciousness: A Systematic Review and Meta-analysis.

OBJECTIVES: The aims of this study are to evaluate the efficacy of transcranial direct current stimulation for improving disorders of consciousness and to compare efficacy of the different etiologies of disorders of consciousness. DESIGN: Randomized controlled trials or crossover trials examining effects of transcranial direct current stimulation in patients with disorders of consciousness were searched in PubMed, Embase, Cochrane Library, and Web of Science. The sample characteristics, etiology, transcranial direct current stimulation treatment characteristics, and outcomes were extracted. Meta-analysis was performed using the RevMan software. RESULTS: We included nine trials providing data with 331 participants and found that transcranial direct current stimulation improved the Coma Recovery Scale-Revised score of disorders of consciousness patients. We found a significant improvement of Coma Recovery Scale-Revised score in the minimally conscious state group (weighted mean difference = 0.77, 95% confidence interval = 0.30-1.23, P = 0.001), but not in the vegetative state or unresponsive wakefulness syndrome group. The effects of transcranial direct current stimulation are related to etiology, as the Coma Recovery Scale-Revised score was improved in the traumatic brain injury group (weighted mean difference = 1.18, 95% confidence interval = 0.60-1.75, P < 0.001), but not in vascular accident and anoxia groups. CONCLUSIONS: This meta-analysis revealed the evidence for positive effects of transcranial direct current stimulation on disorders of consciousness without adverse effects observed in minimally conscious state patients. In particular, transcranial direct current stimulation may be an effective treatment in rehabilitating cognitive functions in people with traumatic brain injury.

Neurotoxic A1 astrocytes promote neuronal ferroptosis via CXCL10/CXCR3 axis in epilepsy.

Epilepsy is a common neurological disorder with a complex etiology. Ferroptosis, a new form of programmed cell death, is characterized by the accumulation of lipid peroxides and associated with seizures. However, the underlying mechanism of ferroptosis in epilepsy remains elusive. Here, we found that GPX4-GSH-dependent neuronal ferroptosis was detected in epileptic mice, which was attenuated with ferroptosis inhibitors. Moreover, activated neurotoxic A1 astrocytes facilitated seizure-related neuronal ferroptosis in epileptic brains. Inhibition of ferroptosis blocked A1 astrocyte-induced neurotoxicity. A1 astrocyte-secreted CXCL10 enhanced STAT3 phosphorylation but suppressed SLC7A11 in neurons via CXCR3, leading to ferroptosis-associated lipid peroxidation in a GPX4-dependent manner. This was in line with clinical findings, showing a significant correlation between neuronal ferroptosis and A1 astrocytes in epileptic patients. In summary, the present data show that A1 astrocyte-induced neuronal ferroptosis contributes to the pathogenesis of epilepsy, which offers a novel therapeutic target for precision medicine.

Distinct mechanisms underlying therapeutic potentials of CD20 in neurological and neuromuscular disease.

Cluster of differentiation 20 (CD20) is an integral membrane protein expressed mainly on different developmental stages of B lymphocytes and rarely on T lymphocytes, and it functions as a link to B cell antigen receptor (BCR) and immune microenvironment via regulating calcium ion influx, cell cycle progression and interaction between isotypic BCRs and their co-receptors. Diverse therapeutic monoclonal antibodies (mAbs) targeting CD20 are generated and grouped into two types based on the ability to redistribute CD20 into lipid rafts, which results in huge differences in response. Currently, multiple anti-CD20 mAbs have been approved as drugs for neurological and neuromuscular diseases with promising clinical efficacy. This review aims to summarize the potential mechanisms, development and current evidence for anti-CD20 therapy in neurological and neuromuscular diseases.

Inhibition of Transient Receptor Potential Vanilloid 4 (TRPV4) Mitigates Seizures.

Astrocytes are critical regulators of the immune/inflammatory response in several human central nervous system (CNS) diseases. Emerging evidence suggests that dysfunctional astrocytes are crucial players in seizures. The objective of this study was to investigate the role of transient receptor potential vanilloid 4 (TRPV4) in 4-aminopyridine (4-AP)-induced seizures and the underlying mechanism. We also provide evidence for the role of Yes-associated protein (YAP) in seizures. 4-AP was administered to mice or primary cultured astrocytes. YAP-specific small interfering RNA (siRNA) was administered to primary cultured astrocytes. Mouse brain tissue and surgical specimens from epileptic patient brains were examined, and the results showed that TRPV4 was upregulated, while astrocytes were activated and polarized to the A1 phenotype. The levels of glial fibrillary acidic protein (GFAP), cytokine production, YAP, signal transducer activator of transcription 3 (STAT3), intracellular Ca2+([Ca2+]i) and the third component of complement (C3) were increased in 4-AP-induced mice and astrocytes. Perturbations in the immune microenvironment in the brain were balanced by TRPV4 inhibition or the manipulation of [Ca2+]i in astrocytes. Knocking down YAP with siRNA significantly inhibited 4-AP-induced pathological changes in astrocytes. Our study demonstrated that astrocytic TRPV4 activation promoted neuroinflammation through the TRPV4/Ca2+/YAP/STAT3 signaling pathway in mice with seizures. Astrocyte TRPV4 inhibition attenuated neuroinflammation, reduced neuronal injury, and improved neurobehavioral function. Targeting astrocytic TRPV4 activation may provide a promising therapeutic approach for managing epilepsy.

TRPV1 channel mediates NLRP3 inflammasome-dependent neuroinflammation in microglia.

Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease in the central nervous system (CNS). The NLRP3 inflammasome is considered an important regulator of immunity and inflammation, both of which play a critical role in MS. However, the underlying mechanism of NLRP3 inflammasome activation is not fully understood. Here we identified that the TRPV1 (transient receptor potential vanilloid type 1) channel in microglia, as a Ca2+ influx-regulating channel, played an important role in NLRP3 inflammasome activation. Deletion or pharmacological blockade of TRPV1 inhibited NLRP3 inflammasome activation in microglia in vitro. Further research revealed that TRPV1 channel regulated ATP-induced NLRP3 inflammasome activation through mediating Ca2+ influx and phosphorylation of phosphatase PP2A in microglia. In addition, TRPV1 deletion could alleviate mice experimental autoimmune encephalomyelitis (EAE) and reduce neuroinflammation by inhibiting NLRP3 inflammasome activation. These data suggested that the TRPV1 channel in microglia can regulate NLRP3 inflammasome activation and consequently mediate neuroinflammation. Meanwhile, our study indicated that TRPV1-Ca2+-PP2A pathway may be a novel regulator of NLRP3 inflammasome activation, pointing to TRPV1 as a potential target for CNS inflammatory diseases.

Anticonvulsant agent DPP4 inhibitor sitagliptin downregulates CXCR3/RAGE pathway on seizure models.

Epilepsy is a common neurological disorder with a complex etiology. Our previous study demonstrated that dipeptidyl peptidase IV (DPP4) may be associated with the pathogenesis of epilepsy. However, whether the DPP4 inhibitor sitagliptin has an anticonvulsant effect and the underlying mechanism remain to be elucidated. In this study, we determined that sitagliptin remarkably attenuated the severity of seizures in a pentylenetetrazole (PTZ)-induced rat model. In addition, sitagliptin decreased epileptiform activity measured by electroencephalography (EEG) recordings and patch-clamp methods. Interestingly, sitagliptin pretreatment downregulated the RAGE-JAK2/STAT3 pathway and decreased the expression of CXCL4 and CXCR3. Moreover, CXCR3 knockdown decreased the expression of RAGE, JAK2 and STAT3 in cultured neurons, which suggests that CXCR3 is upstream of the RAGE-JAK2/STAT3 pathway. Altogether, our present data suggest that sitagliptin has an anticonvulsant effect, which might act via downregulation of the CXCL4/CXCR3 axis, followed by a decrease in RAGE and JAK2/STAT3 expression. Considering these effects, sitagliptin could be considered as a novel potential anticonvulsant drug.

A retrospective study of branch atheromatous disease: Analyses of risk factors and prognosis.

The theory of branch atheromatous disease (BAD) has been commonly underused in clinical practice and research since it was proposed in 1989. In this study, we sought to explore clinical characteristics of its substypes and biomarkers for prognosis of BAD. A total of 176 consecutive patients with BAD were classified into two groups: paramedianpontine artery group (PPA group, n=70) and lenticulostriate artery group (LSA group, n=106). Bivariate analyses were used to explore the relationship between white matter hyperintensities (WMHs), National Institutes of Health Stroke Scale (NIHSS) scores and prognosis evaluated by the modified Rank Scale (mRS) at 6th month after stroke. The differences in prevalence of diabetes mellitus and a history of ischemic heart disease were statistically significant between PPA group and LSA group (χ 2=8.255, P=0.004; χ 2=13.402, P<0.001). The bivariate analyses demonstrated a positive correlation between NIHSS and poor prognosis in patients with BAD and in the two subtype groups, and a positive correlation between WMHs and poor prognosis in the PPA group. It is concluded that a significantly higher prevalence of diabetes mellitus and a history of ischemic heart disease exist in the PPA group than in the LSA group. In addition, high grades of NIHSS scores imply poor prognosis in patients with BAD and in the two subtype groups. Moreover, WMHs are a positive predictor for poor prognosis in patients in the PPA group.

Decreased Methylation Level of H3K27me3 Increases Seizure Susceptibility.

Epigenetic modifications including histone modifications are associated with seizure development and epileptogenesis; however, its underlying mechanism remains to be elucidated. Dipeptidyl peptidase 4 (DPP4) and IL6 are identified as febrile seizure (FS)-related genes using gene microarray analysis in hyperthermia prone (HP) rats. This purpose of the study focused on exploring whether epigenetic modifications marker histone H3 lysine 27 trimethylation (H3K27me3)-regulated DPP4 and IL6 expression further affected seizures development. Herein, we reported broad between-group differences in the global levels of H3K27me3 with increased seizure severity in vivo. Using chromatin immunoprecipitation (ChIP), we identified markedly decreased H3K27me3 enrichment at their promoters of DPP4 and IL6 in vivo. We further showed that hyperthermia significantly decreased protein levels of H3K27me3, increased mRNA levels of DPP4 and IL6 by decreasing H3K27me3 enrichment at their promoters of DPP4 and IL6 in vitro. Importantly, H3K27me3 loss via enhancer of zeste homolog 2 (EZH2) knockdown promoted expression of DPP4 and IL6 via the same mechanism in vitro. EZH2 knockdown also increased neuronal firing frequency in vitro and FS susceptibility in vivo companied with upregulation expression of DPP4 and IL6. Taken together, our study provided the first evidence that hyperthermia-induced decreased of H3K27me3 promoted seizure susceptibility via regulating the expression pattern of DPP4 and IL6. These findings suggested that the methylation level of H3K27me3 might be a key regulator of seizure susceptibility.

Long-term metabolic alterations in a febrile seizure model.

OBJECTIVE: Febrile seizures (FS) are the most common neurological disease in infancy and early childhood, it can lead to metabolic changes and have long-term health implications. Aim of this study was to investigate the long-term effects of FS on metabolism. METHODS: We measured certain metabolic parameters in hyperthermia-prone (HP) rats, which were developed using a selective breeding process and showed a lower seizure threshold than wild-type (WT) rats. Body weight, body length, abdominal circumference and the levels of fasting blood glucose, serum triglyceride, and total cholesterol concentrations were analyzed. The mRNA expression of genes involved in glucose and lipid metabolism was determined by qPCR and the histone methylation level in the liver was determined by western blot. RESULTS: We found that the body weight of the HP rats was significantly lower than that of the WT rats. Similarly, the fasting blood glucose and serum triglyceride levels were lower in the HP group compared with the WT group. These changes were accompanied by increased mRNA expression of genes such as phosphoenolpyruvate carboxykinase (PEPCK) and carnitine palmitoyl transferase-1 (CPT-1), but not peroxisome proliferator-activated receptor α (PPARα). We also found tri-methylation of histone 3 at Lys9 and Lys27 was decreased in the HP group. CONCLUSIONS: These data may suggest an underlying mechanism by which FS have a long-term effect on energy metabolism via histone methylation.

Radix Angelica Sinensis Promotes Synaptic Plasticity During Cognitive Recovery in Chronically Stressed Rats.

The accumulation of chronic stress is associated with cognitive dysfunction. Radix Angelica Sinensis (RAS) has been shown to have neuroprotective potential for treating Alzheimer's disease and vascular dementia. However, the impact of RAS on cognitive impairment induced by chronic stress has not been studied. In the present study, RAS significantly alleviated cognitive deficits in rats subjected to chronic restraint stress. This neuroprotective effect was associated with enhancement of synaptic efficacy by improving field excitatory postsynaptic potential amplitudes, alleviating adverse alterations in the structure of synapses and neurons in the hippocampus, and increasing the levels of brain-derived neurotrophic factor, microtubule-associated protein-2, and synaptophysin in the hippocampus. These findings provide initial evidence for the therapeutic potential of RAS for the treatment of neuronal deterioration caused by chronic stress.

Transcriptome analysis of the hippocampus in novel rat model of febrile seizures.

Febrile seizures (FS) are the most common type of convulsive events in infants and young children, but the precise underlying genetic mechanism remains to be explored. To investigate the underlying pathogenic factors in FS and subsequent epilepsy, alterations in gene expression between the two new strains of rats (hyperthermia-prone [HP] vs hyperthermia-resistant [HR]), were investigated by using the Whole Rat Genome Oligo Microarray. This process identified 1,140 differentially expressed genes (DEGs; 602 upregulated and 538 downregulated), which were analyzed to determine significant Gene Ontology (GO) categories, signaling pathways and gene networks. Based on the GO analyses, the modified genes are closely related to various FS pathogenesis factors, including immune and inflammatory responses and ion transport. Certain DEGs identified have not been previously examined in relation to FS pathogenesis. Among these genes is dipeptidyl peptidase 4 (DPP4), a gene closely linked to interleukin 6 (IL-6), which played a key role in the gene network analysis. Furthermore, sitagliptin, a DPP4 inhibitor significantly decreased epileptic discharge in rats, observed via electroencephalogram, suggesting an important role for DPP4 in FS. The effectiveness of sitagliptin in reducing seizure activity may occur through a mechanism that stabilizes cellular Ca2+ homeostasis. In addition, DPP4 expression may be regulated by DNA methylation. The hippocampal gene expression profiles in novel rat models of FS provides a large database of candidate genes and pathways, which will be useful for researchers interested in disorders of neuronal excitability.

Abnormal levels of brain metabolites may mediate cognitive impairment in stroke-free patients with cerebrovascular risk factors.

OBJECTIVE: conventional vascular risk factors (VRFs) are associated with cognitive impairment independent of stroke and detectable cerebral lesions. We used proton magnetic resonance spectroscopy ((1)H MRS) to examine the hypotheses that abnormal levels of brain metabolites may mediate the relationship between VRFs and cognitive impairment. METHODS: a group of 54 stroke-free subjects with various VRFs underwent comprehensive cognitive assessments and (1)H MRS scan of the left hippocampus and prefrontal cortex. We indirectly measured the concentrations of N-acetylaspartate (NAA), choline, inositol, creatine (Cr) and total concentrations of glutamate plus glutamine (Glx). VRFs were quantified by Framingham stroke risk profile (FSRP) score. Subjects were divided into low- (<10%), medium- (10-20%) and high-risk (>20%) groups according to their FSRP scores. Pearson and partial correlation analysis were used to investigate the correlation between FSRP scores and cognitive performance along with the brain metabolism. RESULTS: compared with subjects in low-risk group, high-risk group subjects had significantly poor performances on the tasks of working memory, delayed recall and executive function. In high-risk group, hippocampal Glx/Cr ratios and prefrontal NAA/Cr ratios were significantly lower than those in low-risk group. Lower prefrontal NAA/Cr ratios were associated with executive dysfunction, and lower hippocampal Glx/Cr ratios were associated with impaired delayed recall. CONCLUSION: abnormal concentrations of brain metabolites and decreased glutamate plus glutamine concentration may play an important role in the pathophysiology of VRF-associated cognitive impairment. Brain metabolites detected by (1)H MRS may serve as important markers for monitoring VRFs burden.

Effects of fluoxetine on brain-derived neurotrophic factor serum concentration and cognition in patients with vascular dementia.

BACKGROUND: Selective serotonin reuptake inhibitors improve cognition in patients with stroke and increase the expression of brain-derived neurotrophic factor (BDNF) in the rat hippocampus. However, the effects of selective serotonin reuptake inhibitors on cognition and serum BDNF levels in patients with vascular dementia are largely unknown. We performed an open-label study to investigate the effects of fluoxetine, a selective serotonin reuptake inhibitor, on cognition and serum BDNF levels in patients with vascular dementia. METHODS: Fifty patients with vascular dementia were randomly allocated to receive fluoxetine (20 mg/day; n=25) or no fluoxetine (control group; n=25) for 12 weeks. Both groups received secondary prevention of stroke. Serum BDNF level, Mini-Mental State Examination (MMSE) score, Ten-Point Clock Drawing score, and Digit Span Test and Verbal Fluency Test scores were measured at baseline and at week 12 in the both groups. RESULTS: The baseline serum BDNF level correlated significantly with the MMSE score. MMSE score, Ten-Point Clock Drawing score, and serum BDNF level increased significantly in the fluoxetine group but not in the control group. The increase in serum BDNF level correlated with the increase in MMSE score in the fluoxetine group. CONCLUSION: Fluoxetine may potentially improve cognition in patients with vascular dementia and requires further investigation. BDNF may play an important role in cognitive recovery.

Fluoxetine enhances Brain Derived Neurotropic Factor Serum Concentration and Cognition in Patients with Vascular Dementia.

Selective serotonin reuptake inhibitors (SSRIs) improve cognition in patients with stroke and increase the expression of brain-derived neurotrophic factor (BDNF) in the rat hippocampus. However, the effects of SSRIs on cognition and BDNF level in vascular dementia (VaD) patients are largely unknown. We performed an open-label study to investigate the effects of fluoxetine, a selective serotonin reuptake inhibitor, on mini-mental state examination (MMSE) score and serum BDNF level in VaD patients. Fifty VaD patients were randomly allocated to receive fluoxetine (20 mg/d; n = 25) or no fluoxetine (control group; n = 25) for 12 weeks. Both groups received secondary prevention of stroke. Baseline serum BDNF level correlated with MMSE score (r = 0.326, p = 0.021). MMSE score increased in the fluoxetine group (15.1 ± 3.0 at baseline vs. 16.1 ± 2.9 at week 12, p = 0.0004) but not in the control group (15.7 ± 2.6 vs. 15.8 ± 2.7, p = 0.566). Serum BDNF level increased in the fluoxetine group (21.2 ± 3.2 ng/ml at baseline vs. 25.7 ± 4.0 ng/ml at week 12, p < 0.001) but not in the control group (21.4 ± 5.8 ng/ml vs. 21.5 ± 6.9 ng/ml, p = 0.921). In the fluoxetine group, the increase in serum BDNF level correlated with the increase in MMSE score (r = 0.413, p = 0.04). The utility of SSRIs during cognitive recovery of VaD patients requires further investigation. BDNF may play an important role in cognitive recovery. (Trial registration: chictr.org, Identifier: ChiCTR-TRC-12002247).

Hyperthermia-induced seizures: development of hyperthermia-prone and hyperthermia-resistant rats.

Febrile seizures (FS), as a multifactorial and genetic disease, are the most common type of convulsive event in infants and young children. Their genetic basis, however, remains elusive. To investigate the genetic mechanisms involved in FS and to identify novel susceptibility genes, we developed two new strains of rats that are hyperthermia-prone (HP, lower seizure threshold) and hyperthermia-resistant (HR, higher seizure threshold) using an established model of hyperthermia-induced seizures combined with selective breeding process. With each subsequent generation, the morbidity of the FS gradually increased in the HP group and gradually decreased in the HR group. Changes in seizure susceptibility between the two genotypes were investigated using kainic acid (KA)-induced seizures and electroencephalography (EEG). The HP rats had a greater seizure severity compared with the HR rats. Our findings may be a significant step toward discovering the genetic mechanisms involved in FS and may elucidate the pathogenesis of this disorder.