Regulation of Cu-Zn superoxide dismutase on SCN2A in SH-SY5Y cells as a potential therapy for temporal lobe epilepsy

Superoxide dismutase and neurological disorders

Superoxide dismutase (SOD) is a common antioxidant enzyme found majorly in living cells. The main physiological role of SOD is detoxification and maintain the redox balance, acts as a first line of defence against Reactive nitrogen species (RNS), Reactive oxygen species (ROS), and other such potentially hazardous molecules. SOD catalyses the conversion of superoxide anion free radicals (O 2 -.) into molecular oxygen (O 2) and hydrogen peroxide (H 2O 2) in the cells. Superoxide dismutases (SODs) are expressed in neurons and glial cells throughout the CNS both intracellularly and extracellularly. Endogenous oxidative stress (OS) linked with enlarged production of reactive oxygen metabolites (ROMs), inflammation, deregulation of redox balance, mitochondrial dysfunction and bioenergetic crisis are found to be prerequisite for neuronal loss in neurological diseases. Clinical and genetic studies indicate a direct correlation between mutations in SOD gene and neurodegenerative diseases, like Amyotrophic Lateral Sclerosis (ALS), Huntington's disease (HD), Parkinson's Disease (PD) and Alzheimer's Disease (AD). Therefore, inhibitors of OS are considered as an optimistic approach to prevent neuronal loss. SOD mimetics like Metalloporphyrin Mn (II)-cyclic polyamines, Nitroxides and Mn (III)- Salen complexes are designed and used as therapeutic extensively in the treatment of neurological disorders. SODs and SOD mimetics are promising future therapeutics in the field of various diseases with OS-mediated pathology.

Circulating glutathione peroxidase and superoxide dismutase levels in patients with epilepsy: A meta-analysis

PURPOSE

Glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) are assessed as oxidative stress markers to determine the impact of oxidation on the levels of GSH-Px and SOD in patients with epilepsy (PWE) and healthy controls.

METHODS

A meta-analysis was completed on twenty-nine published studies. A total of 636 PWE and 665 healthy controls, 303 PWE and 191 controls, and 22 PWE and 22 controls were included to study GSH-Px levels in erythrocytes, serum and plasma, respectively. For SOD studies, there were 610 PWE and 680 controls, 464 PWE and 382 controls, and 62 PWE with 77 controls for erythrocytes, serum and plasma, respectively.

RESULTS

Meta-analysis showed that the erythrocyte SOD level was significantly lower in PWE than in healthy controls (SMD =-1.96; 95% CI [-2.93, -0.99]; P<0.0001). Moreover, the meta-analysis demonstrated that in serum and plasma, SOD levels in PWE were significantly lower than those in healthy controls (SMD =-1.47; 95% CI [-2.47, -0.48]; P<0.0001). Erythrocyte GSH-Px levels had a tendency to decrease in PWE compared with healthy controls (SMD =-0.31; 95% CI [-1.48, 0.85]; P=0.598), but the results showed no significant difference.

CONCLUSION

Our results showed reduced SOD levels in erythrocytes, serum and plasma in PWE, which may be an indicator of oxidative damage in epilepsy. This is the first meta-analysis of circulating GSH-Px and SOD levels in PWE and healthy controls.

Nutritional intake and its impact on patients with epilepsy: an analytical cross-sectional study

BACKGROUND

Anecdotal reports have proposed that diet might influence the occurrence of seizures.

OBJECTIVES

Our objectives were to assess nutritional status in a sample of patients with epilepsy and to investigate the impact of nutrition on epilepsy control.

PATIENTS AND METHODS

One hundred and fifty patients with epilepsy participated in the study. To assess nutritional status, sociodemographic characteristics, anthropometric measurements, dietary food intake, and 24-hour food intake were evaluated. Patients answered questions using a food frequency questionnaire.

RESULTS

In patients with epilepsy, there was insufficient intake of water, fiber, potassium, magnesium and some vitamins (C, E, B12, folate and niacin); suboptimal intake of calories, zinc, calcium, and some vitamins (A, B1 and B6); optimal intake of total fats; and over-intake of proteins, carbohydrates, phosphorus, iron, sodium, and vitamins D and B2. Moreover, there was a statistically significant difference between patients with controlled versus uncontrolled seizures regarding frequency of vegetable intake and percentage of caloric intake from the recommended dietary allowance. Stepwise logistic regression indicated that those with low intake of vegetables had a 2.3 times higher likelihood of uncontrolled seizure occurrence compared to those with a high intake of vegetables per week. Also, those with optimal caloric intake were 80% less likely to have uncontrolled seizures than those with too much caloric intake.

CONCLUSION

Macro- and micronutrient intake were unbalanced in patients with epilepsy. Patients who consumed too many calories and too few vegetables were more likely to have improper seizure control.

Ferulic acid ameliorates pentylenetetrazol-induced seizures by reducing neuron cell death

To investigate the neuroprotective effect of ferulic acid (FA) in a pentylenetetrazol (PTZ)-induced seizures model in rat, the motor response, spatial learning ability and memory capability of the rats were assessed. Both the antioxidation and anti-apoptosis pathways were also investigated. In this study, male Wistar rats were randomly divided into 3 groups (n = 12 in each group). For 28 days, the rats were administered saline alone (i.p. normal saline, NS group), PTZ (40 mg/kg, i.p., PTZ group) once daily to induce seizures, or FA (i.p. 60 mg/kg) 20 min before being given PTZ (40 mg/kg, i.p., FA + PTZ group) to assess the neuroprotective effect of FA. The motor response of the rats was analysed with the Racine scale. The spatial learning and memory capacity of the rats were assessed by the Morris water maze test. The superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were measured, and both in situ staining with the DNA-binding bisbenzimide Hoechst 33258 and TUNEL assays were used to assess apoptosis. Western blotting was used to further analyse the expression of Apaf-1, caspase-9, caspase-3, Bcl-2, Bid, Bax, cleaved caspase-3 and cytochrome c. The results showed that compared to the those of the PTZ group, FA pre-treatment significantly (p <  0.01) reduced the Racine scores starting at day 4, prolonged the latency of the onset of seizure at day 28, reduced the escape latency period starting at day 2, increased the frequency of crossing the platform location, increased the SOD activity, reduced the MDA content and apoptosis percentage, and upregulated the Bcl-2 levels whilst downregulating the Bax, cytochrome c, Apaf-1, caspase-9, caspase-3, cleaved caspase-3 and Bid expression levels. This study demonstrated that pre-treatment with FA exerts strong neuroprotective effects by reducing the motor response and by improving spatial learning ability and memory capacity. The neuroprotective effect may be a result of a reduction in neuron cell death that occurs via the antioxidative and anti-apoptotic pathways.

SCN1B and SCN2B gene variants analysis in dravet syndrome patients: Analysis of 22 cases

Previous research identified SCN1B variants in some cases of Dravet syndrome (DS). We investigated whether SCN1B and SCN2B variants are commonly happened in DS patients without SCN1A variants. A total of 22 DS patients without SCN1A variants and 100 healthy controls were enrolled in this genetic study. DNA from DS patients was sequenced by Sanger method in whole exons of SCN1B and SCN2B genes. We identified two exon variants (c.351C>T, p.G117G and c.467C>T, p.T156M), which were present both in 1000 egenomes database and in healthy controls with a frequency of 0.54% and 4%, 0.06% and 0%, respectively. Additionally, eight intron or 3 prime UTR variants showing benign clinical significance have also been identified. Our results suggest that variants of SCN1B and SCN2B may not be common causes of DS according to our data. Further large sample-size cohort studies are needed to confirm our conclusion.

FOXD3 inhibits SCN2A gene transcription in intractable epilepsy cell models

The expression of sodium voltage-gated channel alpha subunit 2 (SCN2A) is closely related to the development of epilepsy. This study investigated regulatory element of the SCN2A gene involved in epilepsy. An intractable epilepsy cell model was constructed using hippocampal primary neurons and the SH-SY5Y cell line. SCN2A protein and gene expression in cells as well as the level of lactic acid dehydrogenase (LDH) in the cell culture supernatants was detected. Potential regulatory factors of SCN2A and its upstream regulatory elements were identified using the dual-luciferase reporter assay. Finally, the role of the hypothetical transcription factor in epilepsy was examined by using its small interfering RNA (siRNA). Results found that levels of LDH and expression of the hypothetical transcription factor, Forkhead box D3 (FOXD3), was both increased in the model cells, whereas that of SCN2A was decreased. The results of dual-luciferase reporter assays revealed that an upstream region of SCN2A gene spanning from nucleotides -1617 to -1470 was a transcription factor binding region and a trans-acting factor role of FOXD3 was identified in the core region (GGCAAAATTAT). Then the FOXD3 binding site was further verified by the chromatin immunoprecipitation (ChIP) assay and electrophoretic mobility shift assay (EMSA). After SH-SY5Y cells were transfected with FOXD3 siRNA, the release of LDH into culture supernatants and the LDH expression levels in cells were significantly decreased. SCN2A expression in model cells was increased by knockdown of FOXD3. Therefore, this study demonstrated that FOXD3 is a trans-acting factor of SCN2A, and this mechanism may play a role in cell injury after epilepsy.

Anticonvulsant effect of piperine ameliorates memory impairment, inflammation and oxidative stress in a rat model of pilocarpine-induced epilepsy

The primary active component of black pepper is piperine, which is purified and used to treat epilepsy, achieving higher efficiency when purified. The present study was conducted to evaluate whether the anticonvulsant effect of piperine ameliorates pilocarpine-induced epilepsy, and to investigate the mechanism underlying these effects. Epilepsy was induced in Sprague Dawley rats using pilocarpine. Pilocarpine-induced epilepsy in the rats was treated with 40 mg/kg piperine for 45 consecutive days. Status epilepticus and a Morris water maze test were used to analyze the anticonvulsant effects of piperine in the epileptic rats. Inflammation and oxidative stress were then measured using commercially-available kits following piperine treatment. Lastly, the activity of caspase-3 and the protein expression levels of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) were evaluated using commercially-available kits and western blot analysis, respectively. The results demonstrated that treatment with piperine was able to reduce the status epilepticus and prevented memory impairment following pilocarpine-induced epilepsy in rats. The anticonvulsant effects of piperine decreased inflammation and oxidative stress following pilocarpine-induced epilepsy in rats. The upregulated activity of caspase-3 and expression levels of Bax/Bcl-2 were suppressed following treatment with piperine in the rats with pilocarpine-induced epilepsy. These results suggest that the anticonvulsant effects of piperine ameliorate memory impairment, inflammation and oxidative stress in a rat model of pilocarpine-induced epilepsy.

Nutritional Aspects of Treatment in Epileptic Patients

Epilepsy is a neurological disorder characterized by interruption of normal neuronal functions that is manifested by behavioral disorders, changing of awareness level, and presence of some sensory, autonomic and motor symptoms or signs. It is resulted from many different causes. Many antiepileptic drugs (AEDs) are considered to manage epileptic attacks. Some of them change metabolism and absorption of many nutrients. Therefore, epileptic patients may be in higher risk of nutrient deficiency and its unwelcome effects. In the present paper, we intend to review the relationship between nutrition and epilepsy in two aspects. In one aspect we discuss the nutritional status in epileptic patients, the causes of nutritional deficiencies and the way of compensation of the nutrient deficiencies. It will guide these patients to have a healthy life. In another aspect we explain the role of some nutrients and specific diets in management of epileptic attacks. It can help to better control of epileptic attacks in these patients.