LncRNA ILF3-AS1 mediated the occurrence of epilepsy through suppressing hippocampal miR-212 expression

Emerging roles of long non-coding RNAs in human epilepsy

Genome-scale biological studies conducted in the post-genomic era have revealed that two-thirds of human genes do not encode proteins. Most functional non-coding RNA transcripts in humans are products of long non-coding RNA (lncRNA) genes, an abundant but still poorly understood class of human genes. As a result of their fundamental and multitasking regulatory roles, lncRNAs are associated with a wide range of human diseases, including neurological disorders. Approximately 40% of lncRNAs are specifically expressed in the brain, and many of them exhibit distinct spatiotemporal patterns of expression. Comparative genomics approaches have determined that 65%-75% of human lncRNA genes are primate-specific and hence can be posited as a contributing potential cause of the higher-order complexity of primates, including human, brains relative to those of other mammals. Although lncRNAs present important mechanistic examples of epileptogenic functions, the human/primate specificity of lncRNAs questions their relevance in rodent models. Here, we present an in-depth review that supports the contention that human lncRNAs are direct contributors to the etiology and pathogenesis of human epilepsy, as a means to accelerate the integration of lncRNAs into clinical practice as potential diagnostic biomarkers and therapeutic targets. Meta-analytically, the major finding of our review is the commonality of lncRNAs in epilepsy and cancer pathogenesis through mitogen-activated protein kinase (MAPK)-related pathways. In addition, neuroinflammation may be a relevant part of the common pathophysiology of cancer and epilepsy. LncRNAs affect neuroinflammation-related signaling pathways such as nuclear factor kappa- light- chain- enhancer of activated B cells (NF-κB), Notch, and phosphatidylinositol 3- kinase/ protein kinase B (Akt) (PI3K/AKT), with the NF-κB pathway being the most common. Besides the controversy over lncRNA research in non-primate models, whether neuroinflammation is triggered by injury and/or central nervous system (CNS) toxicity during epilepsy modeling in animals or is a direct consequence of epilepsy pathophysiology needs to be considered meticulously in future studies.

Epigenetic regulation in epilepsy: A novel mechanism and therapeutic strategy for epilepsy

Epilepsy is a common neurological disorder characterized by recurrent seizures with excessive and abnormal neuronal discharges. Epileptogenesis is usually involved in neuropathological processes such as ion channel dysfunction, neuronal injury, inflammatory response, synaptic plasticity, gliocyte proliferation and mossy fiber sprouting, currently the pathogenesis of epilepsy is not yet completely understood. A growing body of studies have shown that epigenetic regulation, such as histone modifications, DNA methylation, noncoding RNAs (ncRNAs), N6-methyladenosine (m6A) and restrictive element-1 silencing transcription factor/neuron-restrictive silencing factor (REST/NRSF) are also involved in epilepsy. Through epigenetic studies, we found that the synaptic dysfunction, nerve damage, cognitive dysfunction and brain development abnormalities are affected by epigenetic regulation of epilepsy-related genes in patients with epilepsy. However, the functional roles of epigenetics in pathogenesis and treatment of epilepsy are still to be explored. Therefore, profiling the array of genes that are epigenetically dysregulated in epileptogenesis is likely to advance our understanding of the mechanisms underlying the pathophysiology of epilepsy and may for the amelioration of these serious human conditions provide novel insight into therapeutic strategies and diagnostic biomarkers for epilepsy to improve serious human condition.

RNA therapeutics for epilepsy: An emerging modality for drug discovery

Drug discovery in epilepsy began with the finding of potassium bromide by Sir Charles Locock in 1857. The following century witnessed the introduction of phenotypic screening tests for discovering antiseizure medications (ASMs). Despite the high success rate of developing ASMs, they have so far failed in eliminating drug resistance and in delivering disease-modifying treatments. This emphasizes the need for new drug discovery strategies in epilepsy. RNA-based drugs have recently shown promise as a new modality with the potential of providing disease modification and counteracting drug resistance in epilepsy. RNA therapeutics can be directed either toward noncoding RNAs, such as microRNAs, long noncoding RNAs (ncRNAs), and circular RNAs, or toward messenger RNAs. The former show promise in sporadic, nongenetic epilepsies, as interference with ncRNAs allows for modulation of entire disease pathways, whereas the latter seem more promising in monogenic childhood epilepsies. Here, we describe therapeutic strategies for modulating disease-associated RNA molecules and highlight the potential of RNA therapeutics for the treatment of different patient populations such as sporadic, drug-resistant epilepsy, and childhood monogenic epilepsies.

LncRNA FTX Inhibits Ferroptosis of Hippocampal Neurons Displaying Epileptiform Discharges In vitro Through the miR-142-5p/GABPB1 Axis

Epilepsy is a disabling and drug-refractory neurological disorder. Long non-coding RNAs (lncRNAs) play a vital role in neuronal function and central nervous system development. This study aimed to explore the regulatory mechanism of lncRNA five prime to Xist (FTX) in cell ferroptosis following epilepsy to provide a theoretical foundation for epilepsy management. Hippocampal neurons were isolated from brain tissues of healthy male SD rats, and an in vitro cell model of epilepsy was established using magnesium-free (MGF) induction. Patch-clamp technique was used to determine the action potentials of neurons. Neuronal viability and apoptosis were assessed by CCK-8 assay and flow cytometry. Levels of FTX, miR-142-5p, and GABPB1 were determined by RT-qPCR and Western blot, respectively. The cellular location of FTX was predicted and validated by RNA immunoprecipitation. Dual-luciferase assay verified targeting relationships among FTX, miR-142-5p, and GAPBP1. Levels of ferroptosis indicators and ferroptosis-related proteins were measured using Western blot and corresponding kits. Neuronal ferroptosis and apoptosis increased after MGF induction, and FTX was weakly-expressed in MGF-induced neurons. FTX overexpression attenuated ferroptosis and apoptosis of MGF-induced neurons. miR-142-5p was upregulated after MGF induction and downregulated after FTX overexpression, and FTX targeted miR-142-5p. miR-142-5p overexpression partially negated the inhibitory action of FTX overexpression on ferroptosis of MGF-induced neurons. FTX regulated GABPB1 expression by targeting miR-142-5p. In conclusion, FTX overexpression mitigated ferroptosis of MGF-induced neurons through the miR-142-5p/GABPB1 axis. In conclusion, lncRNA FTX inhibited ferroptosis of MGF-induced rat hippocampal neurons via the miR-142-5p/GABPB1 axis.

Liquid Biopsy in Neurological Diseases

The most recent and non-invasive approach for studying early-stage biomarkers is liquid biopsy. This implies the extraction and analysis of non-solid biological tissues (serum, plasma, saliva, urine, and cerebrospinal fluid) without undergoing invasive procedures to determine disease prognosis. Liquid biopsy can be used for the screening of several components, such as extracellular vesicles, microRNAs, cell-free DNA, cell-free mitochondrial and nuclear DNA, circulating tumour cells, circulating tumour DNA, transfer RNA, and circular DNA or RNA derived from body fluids. Its application includes early disease diagnosis, the surveillance of disease activity, and treatment response monitoring, with growing evidence for validating this methodology in cancer, liver disease, and central nervous system (CNS) disorders. This review will provide an overview of mentioned liquid biopsy components, which could serve as valuable biomarkers for the evaluation of complex neurological conditions, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, epilepsy, stroke, traumatic brain injury, CNS tumours, and neuroinfectious diseases. Furthermore, this review highlights the future directions and potential limitations associated with liquid biopsy.

LncRNA PVT1 Promotes Neuronal Cell Apoptosis and Neuroinflammation by Regulating miR-488-3p/FOXD3/SCN2A Axis in Epilepsy

It is vital to understand the mechanism of epilepsy onset and development. Dysregulated lncRNAs are closely associated with epilepsy. Our work probed the role of lncRNA PVT1/miR-488-3p/FOXD3/SCN2A axis in epilepsy. The mRNA and protein expressions were assessed using qRT-PCR and western blot. MTT assay and TUNEL staining were conducted to assess cell viability and apoptosis, respectively. TNFα, IL-1β and IL-6 levels were analyzed using ELISA. LDH level was tested by Assay Kit. The binding relationship between PVT1, miR-488-3p and FOXD3 were verified using dual luciferase reporter gene assay. The epilepsy model of rats was established by lithium-pilocarpine injection. Nissl staining was performed to evaluate neuronal damage. PVT1 was markedly upregulated in epilepsy model cells. Knockdown of PVT1 increased the viability, while repressed the apoptosis and inflammatory cytokines secretion as well as LDH level in epilepsy cell model. MiR-488-3p alleviated neuronal injury and neuroinflammation in model cells. MiR-488-3p functioned as the direct target of PVT1, and its inhibition neutralized the effects of PVT1 silencing on neuronal cell injury and neuroinflammation in model cells. Furthermore, miR-488-3p inhibited neuronal cell injury and neuroinflammation in model cells by regulating FOXD3/SCN2A pathway. Finally, animal experiments proved that PVT1 promoted epilepsy-induced neuronal cell injury and neuroinflammation by regulating miR-488-3p-mediated FOXD3/SCN2A pathway. PVT1 promoted neuronal cell injury and inflammatory response in epilepsy via inhibiting miR-488-3p and further regulating FOXD3/SCN2A pathway.

The regulatory function of lncRNA and constructed network in epilepsy

BACKGROUND

Epilepsy is a neurological disease characterized by neural network dysfunction. Although most reports indicate that the pathological process of epilepsy is related to inflammation, synaptic plasticity, cell apoptosis, and ion channel dysfunction, the underlying molecular mechanisms of epilepsy are not fully understood.

METHODS

This review summarizes the latest literature on the roles and characteristics of long noncoding RNAs (lncRNAs) in the pathogenesis of epilepsy.

RESULTS

lncRNAs are a class of long transcripts without protein-coding functions that perform important regulatory functions in various biological processes. lncRNAs are involved in the regulation of the pathological process of epilepsy and are abnormally expressed in both patients and animal models. This review provides an overview of research progress in epilepsy, the multifunctional features of lncRNAs, the lncRNA expression pattern related to epileptogenesis and status epilepticus, and the potential mechanisms for the two interactions contributing to epileptogenesis and progression.

CONCLUSION

lncRNAs can serve as new diagnostic markers and therapeutic targets for epilepsy in the future.

Discovery and Validation of Circulating microRNAs as Biomarkers for Epileptogenesis after Experimental Traumatic Brain Injury-The EPITARGET Cohort

Traumatic brain injury (TBI) causes 10-20% of structural epilepsies and 5% of all epilepsies. The lack of prognostic biomarkers for post-traumatic epilepsy (PTE) is a major obstacle to the development of anti-epileptogenic treatments. Previous studies revealed TBI-induced alterations in blood microRNA (miRNA) levels, and patients with epilepsy exhibit dysregulation of blood miRNAs. We hypothesized that acutely altered plasma miRNAs could serve as prognostic biomarkers for brain damage severity and the development of PTE. To investigate this, epileptogenesis was induced in adult male Sprague Dawley rats by lateral fluid-percussion-induced TBI. Epilepsy was defined as the occurrence of at least one unprovoked seizure during continuous 1-month video-electroencephalography monitoring in the sixth post-TBI month. Cortical pathology was analyzed by magnetic resonance imaging on day 2 (D2), D7, and D21, and by histology 6 months post-TBI. Small RNA sequencing was performed from tail-vein plasma samples on D2 and D9 after TBI (n = 16, 7 with and 9 without epilepsy) or sham operation (n = 4). The most promising miRNA biomarker candidates were validated by droplet digital polymerase chain reaction in a validation cohort of 115 rats (8 naïve, 17 sham, and 90 TBI rats [21 with epilepsy]). These included 7 brain-enriched plasma miRNAs (miR-434-3p, miR-9a-3p, miR-136-3p, miR-323-3p, miR-124-3p, miR-212-3p, and miR-132-3p) that were upregulated on D2 post-TBI (p < 0.001 for all compared with naïve rats). The acute post-TBI plasma miRNA profile did not predict the subsequent development of PTE or PTE severity. Plasma miRNA levels, however, predicted the cortical pathology severity on D2 (Spearman ρ = 0.345-0.582, p < 0.001), D9 (ρ = 0.287-0.522, p < 0.001-0.01), D21 (ρ = 0.269-0.581, p < 0.001-0.05) and at 6 months post-TBI (ρ = 0.230-0.433, p < 0.001-0.05). We found that the levels of 6 of 7 miRNAs also reflected mild brain injury caused by the craniotomy during sham operation (ROC AUC 0.76-0.96, p < 0.001-0.05). In conclusion, our findings revealed that increased levels of neuronally enriched miRNAs in the blood circulation after TBI reflect the extent of cortical injury in the brain but do not predict PTE development.

Filtered Cerebrospinal Fluid From Patients With Amyotrophic Lateral Sclerosis Displays an Altered Proteome and Affects Motor Phenotype in a Mouse Model

INTRODUCTION

Cerebrospinal fluid (CSF) has been implicated in amyotrophic lateral sclerosis (ALS) due to its ability to spread inflammatory proteins throughout the nervous system. We hypothesized that filtration of the CSF could remove pathogenic proteins and prevent them from altering motor phenotypes in a mouse model.

METHODS

We filtered the CSF from 11 ALS patients via 100 kilodaltons (kD) molecular weight cut-off filters. We used mass spectrometry-based discovery proteomics workflows to compare protein abundances before and after filtration. To test the effects of CSF filtration on motor function, we injected groups of mice with saline, filtered ALS-CSF, or unfiltered ALS-CSF (n=12 per group) and assessed motor function via pole descent and open field tests.

RESULTS

We identified proteins implicated in ALS pathogenesis and showed that these were removed in significant amounts in our workflow. Key filtered proteins included complement proteins, chitinases, serine protease inhibitors, and neuro-inflammatory proteins such as amyloid precursor protein, chromogranin A, and glial fibrillary acidic protein. Compared to the filtered ALS-CSF mice, unfiltered ALS-CSF mice took longer to descend a pole (10 days post-injection, 11.14 seconds vs 14.25 seconds, p = 0.02) and explored less on an open field (one day post-injection, 21.81 m vs 16.83 m, p = 0.0004).

CONCLUSIONS

We demonstrated the ability to filter proteins from the CSF of ALS patients and identified potentially pathologic proteins that were reduced in quantity. Additionally, we demonstrated the ability of unfiltered ALS-CSF to induce motor deficits in mice on the pole descent and open field tests and showed that filtration could prevent this deficit. Given the lack of effective treatments for ALS, this could be a novel solution for patients suffering from this deadly and irreversible condition.

Role of lncRNAs and circRNAs in epilepsy

Epilepsy is a chronic disorder of with a high prevalence and extensive health burden in almost all age groups of the population. This condition is resulted from disturbance in the balance between excitatory and inhibitory factors in the brain. Genetic elements that affect synaptic connectivity, receptors functions or ion channels have been shown to predispose individuals to the epilepsy. More recently, a body of evidence points to the role of non-coding part of the transcriptome in the pathology of epilepsy. Expression levels of NEAT1, H19, PVT1, ILF3-AS1, GAS5, ZFAS1, UCA1, MALAT1 and SNHG1 have been changed in epileptic patients or animal models of epilepsy. Moreover, circ_ANKMY2, circRNA-0067835 and circHivep2 are among circRNAs which are involved in the pathogenesis of epilepsy. Although the mechanistical impact of these transcripts in the pathogenesis of epilepsy has not been fully explored, disturbances in neuron plasticity, apoptosis or differentiation might be implicated in this process. Expression levels of lncRNAs can be used for discrimination of epileptic patients from normal controls or refractory patients from non-refractory ones. JAK/STAT, Wnt, PI3K/AKT and NF-κB signaling pathways are among the regulated pathways by lncRNAs in the context of epilepsy. In the present review, we summarize the role of lncRNAs and circRNAs in the pathogenesis of epilepsy.

Long non-coding RNAs: Potential therapeutic targets for epilepsy

Epilepsy is a common and disastrous neurological disorder characterized by abnormal firing of neurons in the brain, affecting about 70 million people worldwide. Long non-coding RNAs (LncRNAs) are a class of RNAs longer than 200 nucleotides without the capacity of protein coding, but they participate in a wide variety of pathophysiological processes. Alternated abundance and diversity of LncRNAs have been found in epilepsy patients and animal or cell models, suggesting a potential role of LncRNAs in epileptogenesis. This review will introduce the structure and function of LncRNAs, summarize the role of LncRNAs in the pathogenesis of epilepsy, especially its linkage with neuroinflammation, apoptosis, and transmitter balance, which will throw light on the molecular mechanism of epileptogenesis, and accelerate the clinical implementation of LncRNAs as a potential therapeutic target for treatment of epilepsy.

LncRNA ZNF883-Mediated NLRP3 Inflammasome Activation and Epilepsy Development Involve USP47 Upregulation

The goal of this study was to characterize the mechanisms of long noncoding RNA (lncRNA) ZNF883 regulating NOD-like receptor 3 (NLRP3) inflammasome activation in epilepsy (EP). Rat and cellular EP models were established using pilocarpine and magnesium-free extracellular fluid, respectively, to detect the differential expression of ZNF883, microRNA (miR)-138-5p, ubiquitin-specific peptidase 47 (USP47), and NLRP3. The pathology of the hippocampal neurons was examined by whole-cell patch clamping. The expression of ZNF883, miR-138-5p, and USP47 was modified in epileptic neurons, and the EP rats were injected with sh-ZNF883. Then, alterations in ZNF883, miR-138-5p, and USP47 levels were measured. The histopathology of the hippocampus was detected, along with the detection of IL-6, IL-1β, TNF-α, and NLRP3. Neuronal apoptosis in the rat and cellular EP models was determined. The relationship among ZNF883, miR-138-5p, and USP47 as well as the regulation of NLRP3 ubiquitination by USP47 was determined. ZNF883, USP47, and NLRP3 were increasingly expressed and miR-138-5p was downregulated in epileptic neurons and rats, concurrent with aggravated inflammation and apoptosis. ZNF883 overexpression in epileptic neurons elevated USP47 expression. ZNF883 targeted miR-138-5p and miR-138-5p negatively regulated USP47. In epileptic neurons, inhibiting miR-138-5p or overexpressing USP47 partially reversed the ZNF883 silencing-induced inhibition on NLRP3 inflammasome activation, neuronal apoptosis, and epileptiform activity. ZNF883 silencing in EP rats decreased USP47 and NLRP3, increased miR-138-5p, and inhibited inflammation and apoptosis. USP47 reversed the ubiquitination of NLRP3. ZNF883 inhibits NLRP3 ubiquitination and promotes EP through upregulating USP47 by sponging miR-138-5p.

The Coordination of mTOR Signaling and Non-Coding RNA in Regulating Epileptic Neuroinflammation

Epilepsy accounts for a significant proportion of the burden of neurological disorders. Neuroinflammation acting as the inflammatory response to epileptic seizures is characterized by aberrant regulation of inflammatory cells and molecules, and has been regarded as a key process in epilepsy where mTOR signaling serves as a pivotal modulator. Meanwhile, accumulating evidence has revealed that non-coding RNAs (ncRNAs) interfering with mTOR signaling are involved in neuroinflammation and therefore articipate in the development and progression of epilepsy. In this review, we highlight recent advances in the regulation of mTOR on neuroinflammatory cells and mediators, and feature the progresses of the interaction between ncRNAs and mTOR in epileptic neuroinflammation.

LncRNA, an Emerging Approach for Neurological Diseases Treatment by Regulating Microglia Polarization

Neurological disorders cause untold human disability and death each year. For most neurological disorders, the efficacy of their primary treatment strategies remains suboptimal. Microglia are associated with the development and progression of multiple neurological disorders. Targeting the regulation of microglia polarization has emerged as an important therapeutic strategy for neurological disorders. Their pro-inflammatory (M1)/anti-inflammatory (M2) phenotype microglia are closely associated with neuronal apoptosis, synaptic plasticity, blood-brain barrier integrity, resistance to iron death, and astrocyte regulation. LncRNA, a recently extensively studied non-coding transcript of over 200 nucleotides, has shown great value to intervene in microglia polarization. It can often participate in gene regulation of microglia by directly regulating transcription or sponging downstream miRNAs, for example. Through proper regulation, microglia can exert neuroprotective effects, reduce neurological damage and improve the prognosis of many neurological diseases. This paper reviews the progress of research linking lncRNAs to microglia polarization and neurological diseases.

LncRNA GAS5 promotes epilepsy progression through the epigenetic repression of miR-219, in turn affecting CaMKIIγ/NMDAR pathway

It has been widely reported that dysregulated long-chain noncoding RNAs (lncRNAs) are closely associated with epilepsy. This study aimed to probe the function of lncRNA growth arrest-specific 5 (GAS5), microRNA (miR)-219 and Calmodulin-dependent protein kinase II (CaMKII)γ/N-methyl-D-aspartate receptor (NMDAR) pathway in epilepsy. Epileptic cell and animal models were constructed using magnesium deficiency treatment and diazepam injection, respectively. GAS5 and miR-219 expressions in epileptic cell and animal models were determined using qRT-PCR assay. The protein levels of CaMKIIγ, NMDAR and apoptosis-related proteins levels were assessed by western blot. Cell counting kit-8 (CCK-8) assay was employed to determine cell proliferation. Besides, TNFα, IL-1β, IL-6 and IL-8 levels were analyzed using enzyme-linked immunosorbent assay (ELISA). Furthermore, cell apoptosis was evaluated using TUNEL staining and flow cytometric analysis. Finally, the binding relationship between GAS5 and EZH2 was verified using RIP and ChIP assay. Our results revealed that GAS5 was markedly upregulated in epileptic cell and animal models, while miR-219 was down-regulated. GAS5 knockdown dramatically increased cell proliferation of epileptic cells, whereas suppressed inflammation and the apoptosis. Furthermore, our results showed that GAS5 epigenetically suppressed transcriptional miR-219 expression via binding to EZH2. miR-219 mimics significantly enhanced cell proliferation of epileptic cells, while inhibited inflammation and the apoptosis, which was neutralized by CaMKIIγ overexpression. Finally, miR-219 inhibition reversed the effects of GAS5 silence on epileptic cells, which was eliminated by CaMKIIγ inhibition. In conclusion, GAS5 affected inflammatory response and cell apoptosis of epilepsy via inhibiting miR-219 and further regulating CaMKIIγ/NMDAR pathway (See graphic summary in Supplementary Material).

Non-Coding RNAs: New Biomarkers and Therapeutic Targets for Temporal Lobe Epilepsy

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy; it is considered a network disorder associated with structural changes. Incomplete knowledge of the pathological changes in TLE complicates a therapeutic approach; indeed, 30 to 50% of patients with TLE are refractory to drug treatment. Non-coding RNAs (ncRNAs), acting as epigenetic factors, participate in the regulation of the pathophysiological processes of epilepsy and are dysregulated during epileptogenesis. Abnormal expression of ncRNA is observed in patients with epilepsy and in animal models of epilepsy. Furthermore, ncRNAs could also be used as biomarkers for the diagnosis and prognosis of treatment response in epilepsy. In summary, ncRNAs can represent important mechanisms and targets for the modulation of brain excitability and can provide information on pathomechanisms, biomarkers and novel therapies for epilepsy. In this review, we summarize the latest research advances concerning mainly molecular mechanisms, regulated by ncRNA, such as synaptic plasticity, inflammation and apoptosis, already associated with the pathogenesis of TLE. Moreover, we discuss the role of ncRNAs, such as microRNAs, long non-coding RNAs and circular RNAs, in the pathophysiology of epilepsy, highlighting their use as potential biomarkers for future therapeutic approaches.

Liquid biopsies in epilepsy: biomarkers for etiology, diagnosis, prognosis, and therapeutics

Epilepsy is one of the most common diseases of the central nervous system, impacting nearly 50 million people around the world. Heterogeneous in nature, epilepsy presents in children and adults alike. Currently, surgery is one treatment approach that can completely cure epilepsy. However, not all individuals are eligible for surgical procedures or have successful outcomes. In addition to surgical approaches, antiepileptic drugs (AEDs) have also allowed individuals with epilepsy to achieve freedom from seizures. Others have found treatment through nonpharmacologic approaches such as vagus nerve stimulation, or responsive neurostimulation. Difficulty in accessing samples of human brain tissue along with advances in sequencing technology have driven researchers to investigate sampling liquid biopsies in blood, serum, plasma, and cerebrospinal fluid within the context of epilepsy. Liquid biopsies provide minimal or non-invasive sample collection approaches and can be assayed relatively easily across multiple time points, unlike tissue-based sampling. Various efforts have investigated circulating nucleic acids from these samples including microRNAs, cell-free DNA, transfer RNAs, and long non-coding RNAs. Here, we review nucleic acid-based liquid biopsies in epilepsy to improve understanding of etiology, diagnosis, prediction, and therapeutic monitoring.

A putative role for lncRNAs in epigenetic regulation of memory

The central dogma of molecular genetics is defined as encoded genetic information within DNA, transcribed into messenger RNA, which contain the instructions for protein synthesis, thus imparting cellular functionality and ultimately life. This molecular genetic theory has given birth to the field of neuroepigenetics, and it is now well established that epigenetic regulation of gene transcription is critical to the learning and memory process. In this review, we address a potential role for a relatively new player in the field of epigenetic crosstalk - long non-coding RNAs (lncRNAs). First, we briefly summarize epigenetic mechanisms in memory formation and examine what little is known about the emerging role of lncRNAs during this process. We then focus discussions on how lncRNAs interact with epigenetic mechanisms to control transcriptional programs under various conditions in the brain, and how this may be applied to regulation of gene expression necessary for memory formation. Next, we explore how epigenetic crosstalk in turn serves to regulate expression of various individual lncRNAs themselves. To highlight the importance of further exploring the role of lncRNA in epigenetic regulation of gene expression, we consider the significant relationship between lncRNA dysregulation and declining memory reserve with aging, Alzheimer's disease, and epilepsy, as well as the promise of novel therapeutic interventions. Finally, we conclude with a discussion of the critical questions that remain to be answered regarding a role for lncRNA in memory.

Multi-omic strategies applied to the study of pharmacoresistance in mesial temporal lobe epilepsy

Mesial temporal lobe epilepsy (MTLE) is the most common type of focal epilepsy in adults, and hippocampal sclerosis (HS) is a frequent histopathological feature in patients with MTLE. Pharmacoresistance is present in at least one-third of patients with MTLE with HS (MTLE+HS). Several hypotheses have been proposed to explain the mechanisms of pharmacoresistance in epilepsy, including the effect of genetic and molecular factors. In recent years, the increased knowledge generated by high-throughput omic technologies has significantly improved the power of molecular genetic studies to discover new mechanisms leading to disease and response to treatment. In this review, we present and discuss the contribution of different omic modalities to understand the basic mechanisms determining pharmacoresistance in patients with MTLE+HS. We provide an overview and a critical discussion of the findings, limitations, new approaches, and future directions of these studies to improve the understanding of pharmacoresistance in MTLE+HS. However, it is important to point out that, as with other complex traits, pharmacoresistance to anti-seizure medications is likely a multifactorial condition in which gene-gene and gene-environment interactions play an important role. Thus, studies using multidimensional approaches are more likely to unravel these intricate biological processes.

Identification of significant immune-related genes for epilepsy via bioinformatics analysis

Background

Epilepsy is one of the most common neurological disorders, but its underlying mechanism has remained obscure, and the role of immune-related genes (IRGs) in epilepsy have not yet been investigated. Therefore, in this study, we explored the association between IRGs and epilepsy.

Methods

An IRG list was collected from the ImmPort database. The gene expression profiles of GSE143272 were collected from the Gene Expression Omnibus (GEO) database (https://www.ncbi.nlm.nih.gov/geo/). Differentially expressed genes (DEGs) between epilepsy and normal samples were analyzed, and the intersections between IRGs and DEGs were identified using the VennDiagram package, with the intersected genes subjected to further analysis. Enrichment function for intersected genes were performed, constructed a protein-protein interaction (PPI) network via the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, and the hub genes (top 10) of the PPI network were calculated by the cytoHubba plug-in in Cytoscape. The top correlated genes were selected to perform correlation analysis with immune cells infiltration and expression levels. Finally, we performed validation of the top correlated genes transcriptional expression levels using an animal model.

Results

There were a total of 245 DEGs detected in GSE143272, among which 143 were upregulated and 102 downregulated genes in epilepsy. A total of 44 differential IRGs were obtained via intersection of DEGs and IRGs. Enrichment function analysis of DEGs showed that they played a significant role in immune response. The gene CXCL1 was the most correlated with other differentially expressed IRGs via the PPI network. The results of immune cell infiltration analysis indicated that epilepsy patients had higher activated mast cells infiltration (P=0.021), but lower activated CD4 memory T cells (P=0.001), resting CD4 memory T cells (P=0.011), and gamma delta T cells (P=0.038) infiltration. It was revealed that CXCL1 and activated mast cells (R=0.25, P=0.019) and neutrophils (R=0.3, P=0.0043), and a negative correlation with T cells gamma delta (R=−0.25, P=0.018). The levels of CXCL1 expression were significantly lower in epilepsy patients than those in normal samples.

Conclusions

In this study, the results showed that IRGs such as CXCL1 have a significant influence on epilepsy via regulation of immune cells infiltration.

ILF3-AS1 promotes the aerobic glycolysis and proliferation of melanoma cells by regulating miR-493-5p/PDK1 pathway

BACKGROUND

To investigate the role of ILF3-AS1 in regulating the survival of melanoma and its molecular mechanism.

METHODS

The relative expression level of ILF3-AS1 in melanoma was assessed by qPCR. The effect of ILF3-AS1 and PDK1 on the cell viability was tested by MTT assay. Glucose uptake colorimetric assay, lactate assay, the measurements of extracellular acidification rate (ECAR) and Oxygen consumption rate (OCR) were performed to test the effect of ILF3-AS1 and PDK1 on the cellular glycolysis. Luciferase assay was conducted to detect the interactions of ILF3-AS1, miR-493-5p and PDK1. RNA immunoprecipitation chip (RIP) assay was used to detect the enrichments of ILF3-AS1 and miR-493-5p in the complex. Protein level of PDK1 was detected by western blot analysis.

RESULTS

qPCR revealed that ILF3-AS1 was upregulated in human melanoma cell lines. MTT assay showed that ILF3-AS1 knockdown blunted cell proliferation, which was rescued by the overexpression of PDK1. Glucose uptake colorimetric assay, lactate assay, the measurements of ECAR and OCR indicated that ILF3-AS1 promoted glycolysis through PDK1. Western blotting results showed that ILF3-AS1 overexpression promoted PDK1 expression, which was prevented by miR-493-5p overexpression in SK-MEL-1 cells.

CONCLUSIONS

ILF3-AS1 promotes the aerobic glycolysis and survival of melanoma cells involving miR-493-5p/PDK1 pathway.

HNRNPD interacts with ZHX2 regulating the vasculogenic mimicry formation of glioma cells via linc00707/miR-651-3p/SP2 axis

Studies have found that RNA-binding proteins (RBPs) are dysfunctional and play a significant regulatory role in the development of glioma. Based on The Cancer Genome Atlas database and the previous studies, we selected heterogeneous nuclear ribonucleoprotein (HNRNPD) as the research candidate and sought its downstream targeted genes. In the present study, HNRNPD, linc00707, and specific protein 2 (SP2) were highly expressed, while zinc fingers and homeboxes 2 (ZHX2) and miR-651-3p were remarkedly downregulated in glioma tissues and cells. HNRNPD, linc00707, and SP2 knockdown or ZHX2 and miR-651-3p overexpression suppressed glioma cells proliferation, migration, and invasion and vasculogenic mimicry (VM) formation. Knockdown of HNRNPD increased the stability of ZHX2 mRNA. ZHX2 bound to the promoter region of linc00707 and negatively regulate its expression. Linc00707 could bind with miR-651-3p, while miR-651-3p bound to the 3' untranslated region (3'UTR) of SP2 mRNA to negatively regulate its expression. The transcription factor SP2 directly bound to the promoter regions of the VM formation-related proteins MMP2, MMP9, and VE-cadherin, playing a role in promoting transcription in order to regulate the VM formation ability of glioma cells.

Long Noncoding RNA X-Inactive-Specific Transcript Promotes the Secretion of Inflammatory Cytokines in LPS Stimulated Astrocyte Cell Via Sponging miR-29c-3p and Regulating Nuclear Factor of Activated T cell 5 Expression

BACKGROUND

Astrocyte activation promotes glutamate accumulation and secretion of inflammatory factors, mainly responsible for epilepsy. Long noncoding RNA (lncRNA) X-inactive-specific transcript (XIST) regulates inflammation; however, the biological role and regulatory mechanism of XIST during astrocyte activation remain unclear.

METHODS

In the present study, rat epilepsy model and lipopolysaccharide (LPS)-treated CTX-TNA2 were established. XIST and miR-29c-3p expression were evaluated using quantitative real-time polymerase chain reaction. Nuclear factor of activated T cells 5 (NFAT5) was measured using western blot analysis. Interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and L-glutamate levels in the culture supernatants were assessed using enzyme-linked immunosorbent assay. The binding between XIST and miR-29c-3p and between miR-29c-3p and the 3'-UTR of NFAT5 was analyzed using dual-luciferase reporter, RNA-binding protein immunoprecipitation (RIP), and Biotin pull-down assay. The proliferation and apoptosis were evaluated using CCK8 and flow cytometry, respectively.

RESULTS

XIST expression and NFAT5 protein level was increased, whereas miR-29c-3p expression was decreased in the epilepsy rat model and LPS-treated CTX-TNA2 cells. Silenced XIST expression, miR-29c-3p overexpression, or silenced NFAT5 expression inhibited the secretion of IL-1β, IL-6, and TNF-α and promoted glutamate transport in LPS-treated CTX-TNA2 cells. miR-29c-3p was the potential miRNA sponged by XIST. NFAT5 acted as a direct binding target of miR-29c-3p. Silenced miR-29c-3p expression or NFAT5 overexpression reversed the effect of silenced XIST expression on LPS-treated CTX-TNA2.XIST and miR-29c-3p treatment does not affect NFAT5 mRNA expression, but affects NFAT5 protein level. Furthermore, underexpressed XIST or overexpressed miR-29c-3p in LPS-stimulated CTX-TNA2 can attenuate neuronal apoptosis induced by LPS-stimulated CTX-TNA2.

CONCLUSION

LncRNA XIST promotes the secretion of inflammatory cytokines in LPS- treated CTX-TNA2 via sponging miR-29c-3p and regulating NFAT5 expression.

Long non-coding RNA small nucleolar RNA host gene 1 alleviates the progression of epilepsy by regulating the miR-181a/BCL-2 axis in vitro

PURPOSE

Long non-coding RNAs (lncRNAs) have been reported to be involved in regulating epilepsy. The purpose of this study is to investigate the possibly regulatory mechanism of small nucleolar RNA host gene 1 (SNHG1) on epilepsy.

METHODS

Quantitative real-time PCR was utilized to detect the expression of SNHG1, microRNA (miR)-181a, and B-cell lymphoma-2 (BCL-2). Through an enzyme-linked immunosorbent assay, the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and cyclooxygenase-2 (COX-2) were determined. The viability and apoptosis of CTX-TNA2 cells were measured using MTT assay and flow cytometry analysis, respectively. Western blot assay was performed to analyze the protein levels of Bcl-2, BCL2-associated X, and Caspase-3. The relationships between miR-181a and SNHG1/BCL-2 were confirmed by the dual-luciferase reporter assay.

RESULTS

SNHG1 expression was down-regulated in EP tissues and kainic acid (KA)-induced CTX-TNA2 cells. The apoptosis and release of inflammatory factors (TNF-α, IL-1β, IL-6, and COX-2) in KA-induced CTX-TNA2 cells were suppressed by SNHG1 overexpression and promoted by miR-181a up-regulation. In addition, we confirmed that SNHG1 targeted miR-181a, whereas BCL-2 was a target gene of miR-181a. Negative correlations between SNHG1 and miR-181a, as well as miR-181a and BCL-2 were exhibited. Both the up-regulation of miR-181a and down-regulation of BCL-2 reversed the inhibiting effects of SNHG1 on apoptosis and inflammatory response of KA-induced CTX-TNA2 cells, and the promoting effect upon cell viability.

CONCLUSIONS

SNHG1 alleviated the progression of EP by modulating the miR-181a/BCL-2 axis in vitro, thus SNHG1 could act as a possible therapeutic target for treating EP.

Long-noncoding RNA Peg13 alleviates epilepsy progression in mice via the miR-490-3p/Psmd11 axis to inactivate the Wnt/β-catenin pathway

Epilepsy, one of the most common neurological diseases with spontaneous recurrent seizures, is a severe health problem globally. The present study aimed to study the role and upstream mechanism of 26S proteasome non-ATPase regulatory subunit 11 (Psmd11) in epilepsy. In the current paper, epileptic mice models were successfully established. Hematoxylin and eosin (HE) staining was performed to reveal morphology of hippocampal tissues. Nissl's staining was performed for detection of neuron injury. Enzyme-linked immunosorbent assay (ELISA) was conducted to detect concentrations of pro-inflammatory cytokines. The expression of Psmd11 was downregulated in the hippocampal tissues of epileptic mice, and overexpression of Psmd11 improved the spatial learning and memory of epileptic mice. Further, upregulation of Psmd11 protected epileptic hippocampal neurons from injury. Moreover, Psmd11 overexpression inhibited cell apoptosis, suppressed the activities of microglia and astrocytes, as well as reduced inflammatory response in epileptic hippocampi. Psmd11 was a downstream target of miR-490-3p. Long noncoding RNA (lncRNA) Peg13 bound with miR-490-3p to upregulate Psmd11. Subsequently, rescue experiments revealed that Peg13 suppressed the progression of epilepsy via upregulating Psmd11. Furthermore, Psmd11 was verified to inactivate the Wnt/β-catenin pathway. Peg13 repressed the Wnt/β-catenin pathway via upregulation of Peg13. In conclusion, this paper illuminated the function and upstream mechanism of Psmd11 in epilepsy. Psmd11 was upregulated by Peg13 at a miR-490-3p dependent way, thus inactivating the Wnt/β-catenin pathway and alleviating epilepsy course in mice, which may be a promising approach for epilepsy treatment.