Epilepsy an Update on Disease Mechanisms: The Potential Role of MicroRNAs

Pathophysiology to Risk Factor and Therapeutics to Treatment Strategies on Epilepsy

Epilepsy represents a condition in which abnormal neuronal discharges or the hyperexcitability of neurons occur with synchronicity, presenting a significant public health challenge. Prognostic factors, such as etiology, electroencephalogram (EEG) abnormalities, the type and number of seizures before treatment, as well as the initial unsatisfactory effects of medications, are important considerations. Although there are several third-generation antiepileptic drugs currently available, their multiple side effects can negatively affect patient quality of life. The inheritance and etiology of epilepsy are complex, involving multiple underlying genetic and epigenetic mechanisms. Different neurotransmitters play crucial roles in maintaining the normal physiology of different neurons. Dysregulations in neurotransmission, due to abnormal transmitter levels or changes in their receptors, can result in seizures. In this review, we address the roles played by various neurotransmitters and their receptors in the pathophysiology of epilepsy. Furthermore, we extensively explore the neurological mechanisms involved in the development and progression of epilepsy, along with its risk factors. Furthermore, we highlight the new therapeutic targets, along with pharmacological and non-pharmacological strategies currently employed in the treatment of epileptic syndromes, including drug interventions employed in clinical trials related to epilepsy.

Phthalimide as a versatile pharmacophore scaffold: Unlocking its diverse biological activities

Phthalimide, a pharmacophore exhibiting diverse biological activities, holds a prominent position in medicinal chemistry. In recent decades, numerous derivatives of phthalimide have been synthesized and extensively studied for their therapeutic potential across a wide range of health conditions. This comprehensive review highlights the latest developments in medicinal chemistry, specifically focusing on phthalimide-based compounds that have emerged within the last decade. These compounds showcase promising biological activities, including anti-inflammatory, anti-Alzheimer, antiepileptic, antischizophrenia, antiplatelet, anticancer, antibacterial, antifungal, antimycobacterial, antiparasitic, anthelmintic, antiviral, and antidiabetic properties. The physicochemical profiles of the phthalimide derivatives were carefully analyzed using the online platform pkCSM, revealing the remarkable versatility of this scaffold. Therefore, this review emphasizes the potential of phthalimide as a valuable scaffold for the development of novel therapeutic agents, providing avenues for the exploration and design of new compounds.

Deep brain stimulation for neurological disorders: a protocol for a systematic review with meta-analysis and Trial Sequential Analysis of randomised clinical trials

BACKGROUND

Deep brain stimulation has been used since the 1980s for neurological disorders and the USA and Europe have now approved it for Parkinson's disease, essential tremor, dystonia, and epilepsy. Previous reviews have assessed the effects of deep brain stimulation on different neurological disorders. These reviews all had methodological limitations.

METHODS

This is a protocol for a systematic review based on searches of major medical databases (e.g. MEDLINE, EMBASE, CENTRAL) and clinical trial registries. Two review authors will independently extract data and conduct risk of bias assessment. We will include published and unpublished randomised clinical trial comparing deep brain stimulation versus no intervention, usual care, sham stimulation, medical treatment, or resective surgery for Parkinson's disease, essential tremor, dystonia, or epilepsy. The effects of deep brain stimulation will be analysed separately for each of the different diagnoses. Primary outcomes will be all-cause mortality, disease-specific symptoms, and serious adverse events. Secondary outcomes will be quality of life, depressive symptoms, executive functioning, level of functioning, and non-serious adverse events. Data will be analysed using fixed-effect and random-effects meta-analyses and Trial Sequential Analysis. Risk of bias will be assessed with the Cochrane Risk of Bias tool-version 2, an eight-step procedure to assess if the thresholds for clinical significance are crossed, and the certainty of the evidence will be assessed by Grading of Recommendations, Assessment, Development and Evaluations (GRADE).

DISCUSSION

Deep brain stimulation is increasingly being used for different neurological diseases, and the effects are unclear based on previous evidence. There is a need for a comprehensive systematic review of the current evidence. This review will provide the necessary background for weighing the benefits against the harms when assessing deep brain stimulation as intervention for individual neurological disorders.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO 306,556.

Inhibition of microRNA-129-2-3p protects against refractory temporal lobe epilepsy by regulating GABRA1

BACKGROUND

Accumulating evidence demonstrates that certain microRNAs play critical roles in epileptogenesis. Our previous studies found microRNA (miR)-129-2-3p was induced in patients with refractory temporal lobe epilepsy (TLE). In this study, we aimed to explore the role of miR-129-2-3p in TLE pathogenesis.

METHOD

By bioinformatics, we predicted miR-129-2-3p may target the gene GABRA1 encoding the GABA type A receptor subunit alpha 1. Luciferase assay was used to investigate the regulation of miR-129-2-3p on GABRA1 3'UTR. The dynamic expression of miR-129-2-3p and GABRA1 mRNA and protein levels were measured in primary hippocampal neurons and a rat kainic acid (KA)-induced seizure model by quantitative reverse transcription-polymerase chain reaction (qPCR), Western blotting, and immunostaining. MiR-129-2-3p agomir and antagomir were utilized to explore their role in determining GABRA1 expression. The effects of targeting miR-129-2-3p and GABRA1 on epilepsy were assessed by electroencephalography (EEG) and immunostaining.

RESULTS

Luciferase assay, qPCR, and Western blot results suggested GABRA1 as a direct target of miR-129-2-3p. MiR-129-2-3p level was significantly upregulated, whereas GABRA1 expression downregulated in KA-treated rat primary hippocampal neurons and KA-induced seizure model. In vivo knockdown of miR-129-2-3p by antagomir alleviated the seizure-like EEG findings in accordance with the upregulation of GABRA1. Furthermore, the seizure-suppressing effect of the antagomir was partly GABRA1 dependent.

CONCLUSIONS

The results suggested GABRA1 as a target of miR-129-2-3p in rat primary hippocampal neurons and a rat kainic acid (KA) seizure model. Silencing of miR-129-2-3p exerted a seizure-suppressing effect in rats. MiR-129-2-3p/GABRA1 pathway may represent a potential target for the prevention and treatment of refractory epilepsy.

Curcumin: A Review of Its Effects on Epilepsy

Central nervous system (CNS) diseases pose an enormous healthcare burden, at both an individual and a societal level. Epilepsy has now become one of the most prevalent CNS disorders. Pharmaceutical drugs prescribed for epilepsy often have serious side effects and, for this reason, attention has turned to the use of medicinal plants. Curcumin (diferuloylmethane) is a major component of Curcuma longa and exhibits various pharmacological effects, including anti-inflammatory, antioxidant, and immunoregulatory properties. Here, we have reviewed the literature relating specifically to the antiepileptic effects of curcumin. The evidence suggests a protective effect of curcumin in the control of epileptic seizures, together with a protective effect on the relief of memory impairment, which may stem from its influence on monoamine levels in the brain.

Propofol inhibited apoptosis of hippocampal neurons in status epilepticus through miR-15a-5p/NR2B/ERK1/2 pathway

Although a previous study reported that propofol had a therapeutic effect in status epilepticus (SE), the mechanisms underlying the effect of propofol in SE remain unclear. The aim of this study was to explore the regulatory mechanisms underlying propofol-induced inhibition of SE.A rat SE model was established using the lithium-pilocarpine injection method. A qRT-PCR and Western blot were utilized to detect the expression of relative molecules. Cell apoptosis was evaluated by a flow cytometry assay. The interaction between miR-15a-5p and NR2B was assessed using a luciferase reporter assay.Propofol inhibited cell apoptosis and increased miR-15a-5p expression both in hippocampal tissues of SE rats and low Mg²⁺-induced hippocampal neurons. Propofol-induced attenuation of apoptosis of low Mg²⁺-induced hippocampal neurons was mediated by miR-15a-5p. miR-15a-5p targeted NR2B and negatively regulated its expression. Propofol downregulated NR2B expression, mediated by miR-15a-5p. In terms of the mechanism of action, propofol suppressed the apoptosis of Mg²⁺-induced hippocampal neurons through the miR-15a-5p/NR2B/ERK1/2 pathway. In vivo experiment suggested that propofol inhibited the apoptosis of hippocampal neurons in SE rats by upregulating miR-15a-5p.In terms of the molecular mechanism of propofol, it appears to inhibit apoptosis of hippocampal neurons in SE through the miR-15a-5p/NR2B/ERK1/2 pathway. The findings provide theoretical support for propofol treatment of SE.

Modulation of NMDA receptor by miR-219 in the amygdala and hippocampus of patients with mesial temporal lobe epilepsy

Mesial temporal lobe epilepsy with hippocampal sclerosis is the most frequent form of focal epilepsy in adults, and it is often refractory to drug treatment. Regardless of the efforts on developing new antiepileptic drugs for refractory cases, studies suggest a need for better understanding the molecular bases of epilepsy. The microRNAs have been progressively investigated as potential targets for both epilepsy mechanisms elucidation and treatment. Therefore, the goal of this study was to evaluate the differential expression of miR-219, miR-181b, and miR-195, previously described as regulators of the excitatory neurotransmitter receptors NMDA-R1 and AMPA-GluR2 and inhibitory neurotransmitter GABA_A (α2, β3, and γ2 subunits) in the amygdala and hippocampus of patients with mesial temporal lobe epilepsy. Based on genes and miRNAs' quantitative Polymerase Chain Reaction (qPCR) from 18 patients with epilepsy, our results showed an inverse relationship between miR-219 and NMDA-NR1 expression in both the amygdala and hippocampus in comparison to their expression in controls. NR1 and GluR2 were upregulated in the amygdala of epileptic patients. Low miR-195 expression was observed in the amygdala of patients with epilepsy. Our findings indicate that miR-219 has a possible regulatory role in excitatory neurotransmission in patients with epilepsy, contributing to the new avenue of miRNA biology in drug-resistant epilepsy, reserving huge potential for future applications and clinical interventions in conjunction with existing therapies.

Synthesis, molecular docking, and antiepileptic activity of novel phthalimide derivatives bearing amino acid conjugated anilines

A series of N-aryl-2-(1,3-dioxoisoindolin-2-yl)-3-phenylpropanamides derivatives were synthesized in two steps. Phthalic anhydride and phenylalanine are first reacted under microwave radiation to form 2-(1,3-dioxoisoindolin-2-yl)-3-phenylpropanoic acid, which finally took part in an amidation reaction with different anilines. The final products were characterized by infrared, proton nuclear magnetic resonance (¹H NMR) and mass spectroscopy techniques. The antiepileptic activity of the synthesized compounds at a fixed dose of 10 mg/kg was evaluated by pentylenetetrazole at 70 mg/kg induced seizure threshold method in male mice (n = 5) and compared with aqueous DMSO (10 %, v/v; as negative control) and thalidomide (70 mg/kg; as positive control). The results indicated that compounds 5c, 5e, and 5f as well as thalidomide significantly have higher latency time than what observed with aqueous DMSO (P < 0.05). The seizure latency threshold for 5e and 5f were statistically similar to the results of thalidomide but compound 5c showed significantly higher latency time than thalidomide. While, the electron-deficient benzene ring (5a and 5b) has demonstrated the lowest activity but compound 5e, which is the most electron rich product among tested compounds, showed good antiepileptic activity. Molecular docking was performed in order to understand how the synthetized compounds, interact with gamma-aminobutyric acid (GABA)A receptor. Docking results were in good harmony with experimental data and indicated that lowest binding energy belongs to compound 5c, which has strongest interactions with the active site of GABAA receptor. Compound 5c could be used for further investigation.

Role of non-coding RNA in the pathogenesis of depression

Depression is increasingly threatening human health as a serious psychological problem. However, it is remarkable that the precise mechanism underlying depression remains unelucidated. Recent studies have clarified that non-coding RNA, including but not limited to microRNA, long non-coding RNA, and circular RNA, plays an important role in the pathogenesis of depression. The research results cited in this paper reveal the origin, expression, distribution, function, and mechanism of microRNA in the nervous system. MicroRNA is involved in regulation of life activities, including growth, immune reaction, haematopoiesis, and metabolism, which are significant for maintaining normal physiological functions. Moreover, microRNA plays an important role in cell death and proliferation, development of cancer, and disease prognosis. Here, we also introduce the general research status of long non-coding RNA and circular RNA. Next, descriptive study methods, including fluorescence quantitative polymerase chain reaction, northern blot, microarray technology, RNA-seq, and fluorescent in situ hybridization are discussed. Functional study methods are also summarized and divided into gain- and loss-of-function studies. Moreover, the roles of non-coding RNA in the pathogenesis of depression, including neurogenesis, synaptic plasticity, brain-derived neurotrophic factor expression, HPA axis regulation, neurotransmission, neuropeptide expression, neuro-inflammation, and polyamine synthesis are discussed. Nevertheless, many unknown associations between non-coding RNA and depression remain to be clarified.

Envisioning the neuroprotective effect of Metformin in experimental epilepsy: A portrait of molecular crosstalk

Epilepsy is a neurological disorder characterized by an enduring predisposition to generate and aggravate epileptic seizures affecting around 1% of global population making it a serious health concern. Despite the recent advances in epilepsy research, no disease-modifying treatment able to terminate epileptogenesis have been reported yet reflecting the complexity in understanding the disease pathogenesis. To overcome the current treatment gap against epilepsy, one effective approach is to explore anti-epileptic effects from a drug that are approved to treat non-epileptic diseases. In this regard, Metformin emerged as an ideal candidate which is a first line treatment option for type 2 diabetes mellitus (T2DM), has conferred neuroprotection in several in vivo neurological disorders such as Alzheimer's diseases (AD), Parkinson's disease (PD), Stroke, Huntington's diseases (HD) including epilepsy. In addition, Metformin has ameliorated cognitive alteration, learning and memory induced by epilepsy as well as in animal model of AD. Herein, we review the promising findings demonstrated upon Metformin treatment against animal model of epilepsy however, the precise underlying mechanism of anti-epileptic potential of Metformin is not well understood. However, there is a growing understanding that Metformin demonstrates its anti-epileptic effect mainly via ameliorating brain oxidative damage, activation of AMPK, inhibition of mTOR pathway, downregulation of α-synuclein, reducing apoptosis, downregulation of BDNF and TrkB level. These reflects that Metformin being non-anti-epileptic drug (AED) has a potential to ameliorate the cellular pathways that were impaired in epilepsy reflecting its therapeutical potential against epileptic seizure that might plausibly overcome the limitations of today epilepsy treatment.