MicroRNA-27a-3p Downregulation Inhibits Inflammatory Response and Hippocampal Neuronal Cell Apoptosis by Upregulating Mitogen-Activated Protein Kinase 4 (MAP2K4) Expression in Epilepsy: In Vivo and In Vitro Studies

miR-27a-3p promotes inflammatory response in infectious endophthalmitis via targeting TSC1

Infectious endophthalmitis (IE) poses a significant threat to vision. This study aimed to explore the impact of microRNA (miR)-27a-3p on inflammation in IE. A rat model was developed through intravitreal injection of lipopolysaccharide. Clinical and demographic data were collected for 54 participants: 31 diagnosed with IE and 23 non-infectious patients with idiopathic macular holes. Expression levels of miR-27a-3p and inflammatory genes were quantified via reverse transcription quantitative polymerase chain reaction. Concentrations of inflammatory cytokines in human vitreous samples were measured using enzyme-linked immunosorbent assay. In vitro studies were conducted to explore the target gene of miR-27a-3p. The final animal experiments further verified the role of miR-27a-3p and tuberous sclerosis complex (TSC)1 in inflammatory responses. Results showed that miR-27a-3p was elevated in LPS-treated rats and IE patients. Thirty-one IE patients were divided into the High (n = 15) and Low (n = 16) groups according to the expression of miR-27a-3p. No significant differences were observed in baseline clinical and demographic characteristics between the control and IE patient groups. Pro-inflammatory cytokine mRNA levels and concentrations were notably increased in both LPS-treated rats and the High group of patients. Besides, results showed that TSC1 is a target gene of miR-27a-3p. Moreover, TSC1 inhibition promoted inflammation in rat vitreous samples. In summary, our findings suggested that miR-27a-3p exacerbated inflammatory responses in IE though targeting TSC1, offering novel insights for potential therapeutic strategies targeting miR-27a-3p in the clinical management of IE.

Exploring ncRNAs in epilepsy: From oxidative stress regulation to therapy

Epilepsy is a prevalent neurological illness which is linked with high worldwide burdens. Oxidative stress (OS) is recognized to be among the contributors that trigger the advancement of epilepsy, affecting neuronal excitability and synaptic transmission. Various types of non-coding RNAs (ncRNAs) are known to serve vital functions in many disease mechanisms, including epilepsy. The current review sought to understand better the mechanisms through which these ncRNAs regulate epilepsy's OS-related pathways. We investigated the functions of microRNAs in controlling gene expression at the post-translatory stage and their involvement in OS and neuroinflammation. We also looked at the different regulatory roles of long ncRNAs, including molecular scaffolding, enhancer, and transcriptional activator, during OS. Circular RNAs and their capability to act as miRNA decoys and their consequential impact on epilepsy development were also explored. Our review aimed to improve the current understanding of novel therapies for epilepsy based on the role of ncRNAs in OS pathways. We also demonstrated the roles of ncRNAs in epilepsy treatment and diagnosis, explaining that these molecules play vital roles that could be used in therapy as biomarkers.

Circulating miRNAs as Novel Clinical Biomarkers in Temporal Lobe Epilepsy

Temporal lobe epilepsy (TLE) represents the most common form of refractory focal epilepsy. The identification of innovative clinical biomarkers capable of categorizing patients with TLE, allowing for improved treatment and outcomes, still represents an unmet need. Circulating microRNAs (c-miRNAs) are short non-coding RNAs detectable in body fluids, which play crucial roles in the regulation of gene expression. Their characteristics, including extracellular stability, detectability through non-invasive methods, and responsiveness to pathological changes and/or therapeutic interventions, make them promising candidate biomarkers in various disease settings. Recent research has investigated c-miRNAs in various bodily fluids, including serum, plasma, and cerebrospinal fluid, of TLE patients. Despite some discrepancies in methodologies, cohort composition, and normalization strategies, a common dysregulated signature of c-miRNAs has emerged across different studies, providing the basis for using c-miRNAs as novel biomarkers for TLE patient management.

microRNA profilings identify plasma biomarkers and targets associated with pediatric epilepsy patients

BACKGROUND

Although previous studies show that microRNAs (miRNAs) can potentially be used as diagnostic markers for epilepsy, there are very few analyses of pediatric epilepsy patients.

METHODS

miRNA profiles using miRNA-seq was performed on plasma samples from 14 pediatric epileptic patients and 14 healthy children. miRNA miR-27a-3p that were significantly changed between two groups were further evaluated. The potential target genes of miR-27a-3p were screened through unbiased mRNA-seq and further validated using Western blot and immunohistochemistry in HEK-293T cells and in the brains of mice with epilepsy induced by lithium chloride-pilocarpine.

RESULTS

We found 82 upregulated and 76 downregulated miRNAs in the plasma from pediatric patients compared with controls (p < 0.01), of which miR-27a-3p exhibited a very low p value (p < 0.0001) and validated in additional plasma samples. Two genes, GOLM1 and LIMK1, whose mRNA levels were decreased (p < 0.001) with the increase of miR-27a-3p were further validated in both HEK-293T cells and in epileptic mice.

CONCLUSIONS

MiR-27a-3p exhibits potential as a diagnostic and therapeutic marker for epilepsy. We postulate that additional studies on the downstream targets of miR-27a-3p will unravel its roles in epileptogenesis or disease progression.

IMPACT

A total of 158 differentially expressed miRNAs were detected in plasma between epileptic and control children. Plasma miR-27a-3p was one of the miRNAs with a low p value. GOLM1 and LIMK1 were validated as downstream target genes of miR-27a-3p. miR-27a-3p has potential as a diagnostic and therapeutic marker for epilepsy.

Non-coding RNAs and neuroinflammation: implications for neurological disorders

Neuroinflammation is considered a balanced inflammatory response important in the intrinsic repair process after injury or infection. Under chronic states of disease, injury, or infection, persistent neuroinflammation results in a heightened presence of cytokines, chemokines, and reactive oxygen species that result in tissue damage. In the CNS, the surrounding microglia normally contain macrophages and other innate immune cells that perform active immune surveillance. The resulting cytokines produced by these macrophages affect the growth, development, and responsiveness of the microglia present in both white and gray matter regions of the CNS. Controlling the levels of these cytokines ultimately improves neurocognitive function and results in the repair of lesions associated with neurologic disease. MicroRNAs (miRNAs) are master regulators of the genome and subsequently control the activity of inflammatory responses crucial in sustaining a robust and acute immunological response towards an acute infection while dampening pathways that result in heightened levels of cytokines and chemokines associated with chronic neuroinflammation. Numerous reports have directly implicated miRNAs in controlling the abundance and activity of interleukins, TGF-B, NF-kB, and toll-like receptor-signaling intrinsically linked with the development of neurological disorders such as Parkinson's, ALS, epilepsy, Alzheimer's, and neuromuscular degeneration. This review is focused on discussing the role miRNAs play in regulating or initiating these chronic neurological states, many of which maintain the level and/or activity of neuron-specific secondary messengers. Dysregulated miRNAs present in the microglia, astrocytes, oligodendrocytes, and epididymal cells, contribute to an overall glial-specific inflammatory niche that impacts the activity of neuronal conductivity, signaling action potentials, neurotransmitter robustness, neuron-neuron specific communication, and neuron-muscular connections. Understanding which miRNAs regulate microglial activation is a crucial step forward in developing non-coding RNA-based therapeutics to treat and potentially correct the behavioral and cognitive deficits typically found in patients suffering from chronic neuroinflammation.

The emerging role of miRNAs in epilepsy: From molecular signatures to diagnostic potential

Epilepsy is a medical condition characterized by intermittent seizures accompanied by changes in consciousness. Epilepsy significantly impairs the daily functioning and overall well-being of affected individuals. Epilepsy is a chronic neurological disorder characterized by recurrent seizures resulting from various dysfunctions in brain activity. The molecular processes underlying changes in neuronal structure, impaired apoptotic responses in neurons, and disruption of regenerative pathways in glial cells in epilepsy remain unknown. MicroRNAs (miRNAs) play a crucial role in regulating apoptosis, autophagy, oxidative stress, neuroinflammation, and the body's regenerative and immune responses. miRNAs have been shown to influence many pathogenic processes in epilepsy including inflammatory responses, neuronal necrosis and apoptosis, dendritic growth, synaptic remodeling, and other processes related to the development of epilepsy. Therefore, the purpose of our current analysis was to determine the role of miRNAs in the etiology and progression of epilepsy. Furthermore, they have been examined for their potential application as biomarkers and therapeutic targets.

The role of microRNAs in neurobiology and pathophysiology of the hippocampus

MicroRNAs (miRNAs) are short non-coding and well-conserved RNAs that are linked to many aspects of development and disorders. MicroRNAs control the expression of genes related to different biological processes and play a prominent role in the harmonious expression of many genes. During neural development of the central nervous system, miRNAs are regulated in time and space. In the mature brain, the dynamic expression of miRNAs continues, highlighting their functional importance in neurons. The hippocampus, as one of the crucial brain structures, is a key component of major functional connections in brain. Gene expression abnormalities in the hippocampus lead to disturbance in neurogenesis, neural maturation and synaptic formation. These disturbances are at the root of several neurological disorders and behavioral deficits, including Alzheimer's disease, epilepsy and schizophrenia. There is strong evidence that abnormalities in miRNAs are contributed in neurodegenerative mechanisms in the hippocampus through imbalanced activity of ion channels, neuronal excitability, synaptic plasticity and neuronal apoptosis. Some miRNAs affect oxidative stress, inflammation, neural differentiation, migration and neurogenesis in the hippocampus. Furthermore, major signaling cascades in neurodegeneration, such as NF-Kβ signaling, PI3/Akt signaling and Notch pathway, are closely modulated by miRNAs. These observations, suggest that microRNAs are significant regulators in the complicated network of gene regulation in the hippocampus. In the current review, we focus on the miRNA functional role in the progression of normal development and neurogenesis of the hippocampus. We also consider how miRNAs in the hippocampus are crucial for gene expression mechanisms in pathophysiological pathways.

The dysregulation of miRNAs in epilepsy and their regulatory role in inflammation and apoptosis

Epilepsy is a neurological disorder that impacts millions of people worldwide, and it is characterized by the occurrence of recurrent seizures. The pathogenesis of epilepsy is complex, involving dysregulation of various genes and signaling pathways. MicroRNAs (miRNAs) are a group of small non-coding RNAs that play a vital role in the regulation of gene expression. They have been found to be involved in the pathogenesis of epilepsy, acting as key regulators of neuronal excitability and synaptic plasticity. In recent years, there has been a growing interest in exploring the miRNA regulatory network in epilepsy. This review summarizes the current knowledge of the regulatory miRNAs involved in inflammation and apoptosis in epilepsy and discusses its potential as a new avenue for developing targeted therapies for the treatment of epilepsy.

Role of epigenetic abnormalities and intervention in obstructive sleep apnea target organs

ABSTRACT

Obstructive sleep apnea (OSA) is a common condition that has considerable impacts on human health. Epigenetics has become a rapidly developing and exciting area in biology, and it is defined as heritable alterations in gene expression and has regulatory effects on disease progression. However, the published literature that is integrating both of them is not sufficient. The purpose of this article is to explore the relationship between OSA and epigenetics and to offer better diagnostic methods and treatment options. Epigenetic modifications mainly manifest as post-translational modifications in DNA and histone proteins and regulation of non-coding RNAs. Chronic intermittent hypoxia-mediated epigenetic alterations are involved in the progression of OSA and diverse multiorgan injuries, including cardiovascular disease, metabolic disorders, pulmonary hypertension, neural dysfunction, and even tumors. This article provides deeper insights into the disease mechanism of OSA and potential applications of targeted diagnosis, treatment, and prognosis in OSA complications.

miRNA dysregulation in traumatic brain injury and epilepsy: a systematic review to identify putative biomarkers for post-traumatic epilepsy

Traumatic brain injury (TBI) leads to post-traumatic epilepsy (PTE); hence, both TBI and PTE share various similar molecular mechanisms. MicroRNA (miRNA) is a small noncoding RNA that acts as a gene-silencing molecule. Notably, the dysregulation of miRNAs in various neurological diseases, including TBI and epilepsy, has been reported in several studies. However, studies on commonly dysregulated miRNAs and the regulation of shared pathways in both TBI and epilepsy that can identify potential biomarkers of PTE are still lacking. This systematic review covers the peer-review publications of TBI and database studies of epilepsy-dysregulated miRNAs of clinical studies. For TBI, 290 research articles were identified after screening, and 12 provided data for dysregulated miRNAs in humans. The compiled data suggest that 85 and 222 miRNAs are consecutively dysregulated in TBI and epilepsy. In both, 10 miRNAs were found to be commonly dysregulated, implying that they are potentially dysregulated miRNAs for PTE. Furthermore, the targets and involvement of each putative miRNA in different pathways were identified and evaluated. Additionally, clusters of predicted miRNAs were analyzed. Each miRNA's regulatory role was linked with apoptosis, inflammation, and cell cycle regulation pathways. Hence, these findings provide insight for future diagnostic biomarkers.

Stage- and Subfield-Associated Hippocampal miRNA Expression Patterns after Pilocarpine-Induced Status Epilepticus

OBJECTIVE

To investigate microRNA (miRNA) expression profiles before and after pilocarpine-induced status epilepticus (SE) in the cornu ammonis (CA) and dentated gyrus (DG) areas of the mouse hippocampus, and to predict the downstream proteins and related pathways based on bioinformatic analysis.

METHODS

An epileptic mouse model was established using a pilocarpine injection. Brain tissues from the CA and DG were collected separately for miRNA analysis. The miRNAs were extracted using a kit, and the expression profiles were generated using the SurePrint G3 Mouse miRNA microarray and validated. The intersecting genes of TargetScan and miRanda were selected to predict the target genes of each miRNA. For gene ontology (GO) studies, the parent-child-intersection (pci) method was used for enrichment analysis, and Benjamini-Hochberg was used for multiple test correction. The Kyoto Encyclopedia of Genes and Genomes (KEGG) was used to detect disease-related pathways among the large list of miRNA-targeted genes. All analyses mentioned above were performed at the time points of control, days 3, 14, and 60 post-SE.

RESULTS

Control versus days 3, 14, and 60 post-SE: in the CA area, a total of 131 miRNAs were differentially expressed; 53, 49, and 26 miRNAs were upregulated and 54, 10, and 22 were downregulated, respectively. In the DG area, a total of 171 miRNAs were differentially expressed; furthermore, 36, 32, and 28 miRNAs were upregulated and 78, 58, and 44 were downregulated, respectively. Of these, 92 changed in both the CA and DG, 39 only in the CA, and 79 only in the DG area. The differentially expressed miRNAs target 11-1630 genes. Most of these proteins have multiple functions in epileptogenesis. There were 15 common pathways related to altered miRNAs: nine different pathways in the CA and seven in the DG area.

CONCLUSIONS

Stage- and subfield-associated hippocampal miRNA expression patterns are closely related to epileptogenesis, although the detailed mechanisms need to be explored in the future.

FOXO4 alleviates hippocampal neuronal damage in epileptic mice via the miR-138-5p/ROCK2 axis

Epilepsy (EP) is one of the most universal neurological disorders. This study investigated the mechanism of forkhead box protein O4 (FOXO4) on hippocampal neuronal damage in EP mice. Initially, the EP mouse model and the in vitro HT-22 cell model were established. EP seizures and neuronal damage in mice were assessed. FOXO4, microRNA (miR)-138-5p, and rho-associated coiled-coil containing protein kinase 2 (ROCK2) levels in hippocampal tissues or HT-22 cells were examined. The cell viability and apoptosis of HT-22 cells were determined. The concentrations of oxidative stress markers and the levels of inflammatory cytokines in hippocampal tissues or HT-22 cells were detected. We found that FOXO4 was poorly expressed in EP. FOXO4 overexpression alleviated hippocampal neuronal damage in EP mice and improved HT-22 cell viability and inhibited apoptosis, and decreased oxidative stress and inflammation in hippocampal tissue and HT-22 cells. The bindings of miR-138-5p to FOXO4 and ROCK2 were analyzed, which showed that FOXO4 promoted miR-138-5p via binding to the miR-138-5p promoter region, and miR-138-5p inhibited ROCK2 expression. Joint experiments showed that miR-138-5p suppression or ROCK2 overexpression reversed the alleviation of FOXO4 overexpression on hippocampal neuronal damage. FOXO4 inhibited ROCK2 expression via promoting miR-138-5p expression, thus alleviating hippocampal neuronal damage in EP mice.

MicroRNA‑27a Aggravates Ferroptosis during early Ischemic Stroke of Rats Through Nrf2

Ischaemic stroke (IS) is characterized by high morbidity, disability and mortality and lacks effective solutions. MiRNA-27a has been implicated in ferroptosis, but evidence that miRNA-27a regulates ferroptosis in ischaemic stroke is lacking. Nrf2 could reduce brain tissue injury in ischaemic stroke and resist ferroptosis. The current study aimed to investigate the relationship between miRNA-27a/Nrf2 and ferroptosis in ischaemic stroke. In this study, IS was simulated using a permanent middle cerebral artery occlusion (pMCAO) model. The degree of brain tissue injury was assessed by conducting TTC staining and neurological function scoring. MiRNA-27a expression levels were altered via the intracerebroventricular injection of miRNA‑27a agonist or antagonist. Glutathione peroxidase 4 (GPX4), glutathione (GSH), Fe and malondialdehyde (MDA) are considered biomarkers for ferroptosis. The expression of GPX4 and Nrf2 was analysed by Western blot assay. The GSH, Fe and MDA contents were detected by detection kits. We found that the expression levels of Fe and MDA were increased, while GPX4 and GSH were decreased in the pMCAO groups compared with the control group. These results indicated that ferroptosis intensified over time during IS. In addition, the miRNA‑27a agonist significantly aggravated ferroptosis and reduced neurological function scores compared with those of the control group. Subsequently, a luciferase reporter gene system verified the targeted binding of miRNA‑27a to Nrf2. The results showed that miRNA‑27a inhibited Nrf2 in a targeted manner, which also exacerbated the extent of ferroptosis. However, the miRNA‑27a antagonist reversed the miR‑27a agonist‑mediated effects. Therefore, the present study indicated that miRNA‑27a may aggravate brain tissue ferroptosis during ischaemic stroke, potentially by inhibiting Nrf2.

Neuroendocrine microRNAs linked to energy homeostasis: future therapeutic potential

The brain orchestrates whole-body metabolism through an intricate system involving interneuronal crosstalk and communication. Specifically, a key player in this complex circuitry is the hypothalamus that controls feeding behaviour, energy expenditure, body weight and metabolism, whereby hypothalamic neurons sense and respond to circulating hormones, nutrients, and chemicals. Dysregulation of these neurons contributes to the development of metabolic disorders, such as obesity and type 2 diabetes. The involvement of hypothalamic microRNAs, post-transcriptional regulators of gene expression, in the central regulation of energy homeostasis has become increasingly apparent, although not completely delineated. This review summarizes current evidence demonstrating the regulation of feeding-related neuropeptides by brain-derived microRNAs as well as the regulation of specific miRNAs by nutrients and other peripheral signals. Moreover, the involvement of microRNAs in the central nervous system control of insulin, leptin, and estrogen signal transduction is examined. Finally, the therapeutic and diagnostic potential of microRNAs for metabolic disorders will be discussed and the regulation of brain-derived microRNAs by nutrients and other peripheral signals is considered. Demonstrating a critical role of microRNAs in hypothalamic regulation of energy homeostasis is an innovative route to uncover novel biomarkers and therapeutic candidates for metabolic disorders.

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.

H19 silencing decreases kainic acid-induced hippocampus neuron injury via activating the PI3K/AKT pathway via the H19/miR-206 axis

Temporal lobe epilepsy (TLE) is the most common type of intractable epilepsy and is refractory to medications. However, the role and mechanism of H19 in regulating TLE remains largely undefined. Expression of H19 and miR-206 was detected using real-time quantitative PCR (RT-qPCR). Cell apoptosis, autophagy and inflammatory response were determined by flow cytometry, western blotting and enzyme-linked immunosorbent assay (ELISA). The interaction between H19 and miR-206 was predicted on the miRcode database and confirmed by luciferase reporter assay, RNA immunoprecipitation (RIP) and RNA pull-down. H19 was upregulated and miR-206 was downregulated in the rat hippocampus neurons after kainic acid (KA) treatment. Functionally, both H19 knockdown and miR-206 overexpression weakened KA-induced apoptosis, autophagy, inflammatory response, and oxidative stress in hippocampus neurons. Mechanically, the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway was activated by H19 knockdown and miR-206 was confirmed to be targeted and negatively regulated by H19. Moreover, downregulation of miR-206 could counteract the effects of H19 knockdown in KA-induced hippocampus neurons. Knockdown of H19 suppressed hippocampus neuronal apoptosis, autophagy and inflammatory response presumably through directly upregulating miR-206 and activating the PI3K/AKT signaling pathway.

Transporter Regulation in Critical Protective Barriers: Focus on Brain and Placenta

Drug transporters play an important role in the maintenance of chemical balance and homeostasis in different tissues. In addition to their physiological functions, they are crucial for the absorption, distribution, and elimination of many clinically important drugs, thereby impacting therapeutic efficacy and toxicity. Increasing evidence has demonstrated that infectious, metabolic, inflammatory, and neurodegenerative diseases alter the expression and function of drug transporters. However, the current knowledge on transporter regulation in critical protective barriers, such as the brain and placenta, is still limited and requires more research. For instance, while many studies have examined P-glycoprotein, it is evident that research on the regulation of highly expressed transporters in the blood–brain barrier and blood–placental barrier are lacking. The aim of this review is to summarize the currently available literature in order to better understand transporter regulation in these critical barriers.

Identification of Ion Channel-Related Genes and miRNA-mRNA Networks in Mesial Temporal Lobe Epilepsy

Objective: It aimed to construct the miRNA-mRNA regulatory network related to ion channel genes in mesial temporal lobe epilepsy (mTLE), and further identify the vital node in the network.

Methods: Firstly, we identified ion channel-related differentially expressed genes (DEGs) in mTLE using the IUPHAR/BPS Guide to Pharmacology (GTP) database, neXtProt database, GeneCards database, and the high-throughput sequencing dataset. Then the STRING online database was used to construct a protein-protein interaction (PPI) network of DEGs, and the hub module in the PPI network was identified using the cytoHubba plug-in of Cytoscape software. In addition, the Single Cell Portal database was used to distinguish genes expression in different cell types. Based on the TarBase database, EpimiRBase database and the high-throughput sequencing dataset GSE99455, miRNA-mRNA regulatory network was constructed from selected miRNAs and their corresponding target genes from the identified DEGs. Finally, the rats were selected to construct chronic li-pilocarpine epilepsy model for the next stage experimental verification, and the miR-27a-3p mimic was used to regulate the miRNA expression level in PC12 cells. The relative expression of miR-27a-3p and its targeting mRNAs were determined by RT-qPCR.

Results: 80 mTLE ion channel-related DEGs had been screened. The functional enrichment analysis results of these genes were highly enriched in voltage-gated channel activation and ion transport across membranes. In addition, the hub module, consisting of the Top20 genes in the protein-protein interaction (PPI) network, was identified, which was mainly enriched in excitatory neurons in the CA3 region of the hippocampus. Besides, 14 miRNAs targeting hub module genes were screened, especially the miR-27a-3p deserving particular attention. miR-27a-3p was capable of regulating multiple mTLE ion channel-related DEGs. Moreover, in Li–pilocarpine-induced epilepsy models, the expression level of miR-27a-3p was increased and the mRNAs expression level of KCNB1, SCN1B and KCNQ2 was decreased significantly. The mRNAs expression level of KCNB1 and KCNQ2 was decreased significantly following PC12 cells transfection with miR-27a-3p mimics.

Conclusion: The hub ion channel-related DEGs in mTLE and the miRNA-mRNA regulatory networks had been identified. Moreover, the network of miR-27a-3p regulating ion channel genes will be of great value in mTLE.

Insights into nervous system repair from the fruit fly

Millions of people experience injury to the central nervous system (CNS) each year, many of whom are left permanently disabled, providing a challenging hurdle for the field of regenerative medicine. Repair of damage in the CNS occurs through a concerted effort of phagocytosis of debris, cell proliferation and differentiation to produce new neurons and glia, distal axon/dendrite degeneration, proximal axon/dendrite regeneration and axon re-enwrapment. In humans, regeneration is observed within the peripheral nervous system, while in the CNS injured axons exhibit limited ability to regenerate. This has also been described for the fruit fly Drosophila. Powerful genetic tools available in Drosophila have allowed the response to CNS insults to be probed and novel regulators with mammalian orthologs identified. The conservation of many regenerative pathways, despite considerable evolutionary separation, stresses that these signals are principal regulators and may serve as potential therapeutic targets. Here, we highlight the role of Drosophila CNS injury models in providing key insight into regenerative processes by exploring the underlying pathways that control glial and neuronal activation in response to insult, and their contribution to damage repair in the CNS.

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.

Unlocking the Memory Component of Alzheimer’s Disease:Biological Processes and Pathways across Brain Regions

Alzheimer’s Disease (AD) is a neurodegenerative disorder characterized by a progressive loss of memory and a general cognitive decline leading to dementia. AD is characterized by changes in the behavior of the genome and can be traced across multiple brain regions and cell types. It is mainly associated with β-amyloid deposits and tau protein misfolding, leading to neurofibrillary tangles. In recent years, however, research has shown that there is a high complexity of mechanisms involved in AD neurophysiology and functional decline enabling its diverse presentation and allowing more questions to arise. In this study, we present a computational approach to facilitate brain region-specific analysis of genes and biological processes involved in the memory process in AD. Utilizing current genetic knowledge we provide a gene set of 265 memory-associated genes in AD, combinations of which can be found co-expressed in 11 different brain regions along with their functional role. The identified genes participate in a spectrum of biological processes ranging from structural and neuronal communication to epigenetic alterations and immune system responses. These findings provide new insights into the molecular background of AD and can be used to bridge the genotype–phenotype gap and allow for new therapeutic hypotheses.

Aberrant expression of miRNAs in epilepsy

Epilepsy is manifested by intermittent convulsions and alterations in consciousness. This disorder has serious effects on daily functions and physical and mental health of affected patients. A variety of temporary irregularities in the function of brain can results in epilepsy. The molecular mechanism of epilepsy and the underlying causes of abnormal apoptotic responses in neurons, dysregulation of regenerative mechanisms in glial cells and abnormal immune reactions in the context of epilepsy are not clear. microRNAs (miRNAs) as important regulators of cell apoptosis as well as regenerative and immune responses have been shown to affect pathologic events in epilepsy. In the current review, we aimed at defining the role of miRNAs in the pathophysiology of epilepsy. We have listed dysregulated miRNAs in animal models of epilepsy and human subjects. miR-25-3p, miR-494, miR-139-5p, miR-101a-3p, miR-344a, miR-129, miR-298 and miR-187 are among down-regulated miRNAs in epilepsy. Moreover, expressions of miR-132, miR-146a, miR-181a and miR-155 have been reported to be increased in epilepsy. A number of genetic variants within miRNAs can affect risk of epilepsy. We discuss the role of miRNAs in the development of epilepsy.

Role of miR-27a in the regulation of cellular function via the inhibition of MAP2K4 in patients with asthma

Asthma is a respiratory disease with a clinically high incidence, and repeated attacks of asthma severely affect the quality of life and even pose a threat to health, leading to severe burdens on families and even the society. A thorough understanding of the pathogenesis of asthma is essential for the prevention and treatment of asthma. This study aimed to examine the effect of the microRNA miR-27a on asthma and its relationship with mitogen activated protein kinase 4 (MAP2K4). Patients with asthma admitted to our hospital from August 2016 to August 2018 and healthy participants in the same period were included in this prospective analysis. The mRNA expression levels of miR-27a and MAP2K4 in peripheral blood were determined. Airway smooth muscle cells (ASMCs) were used to study the effects of miR-27a and MAP2K4 on cell biological behavior. The relationship between miR-27a and MAP2K4 was verified using dual-luciferase reporter assay. miR-27a expression was increased and MAP2K4 mRNA expression was decreased in asthma (P < 0.05). Increasing miR-27a expression and inhibiting MAP2K4 expression could enhance the activity of ASMCs, whereas inhibiting miR-27a expression and increasing MAP2K4 expression had the opposite effect (P < 0.05). Dual-luciferase reporter assay results showed that the fluorescence activity of MAP2K4-wild type was inhibited by increased miR-27a expression (P < 0.05). miR-27a promotes the proliferation and invasion of ASMCs by targeting MAP2K4 and is involved in the occurrence of asthma.

Sleep Disruption Worsens Seizures: Neuroinflammation as a Potential Mechanistic Link

Sleep disturbances, such as insomnia, obstructive sleep apnea, and daytime sleepiness, are common in people diagnosed with epilepsy. These disturbances can be attributed to nocturnal seizures, psychosocial factors, and/or the use of anti-epileptic drugs with sleep-modifying side effects. Epilepsy patients with poor sleep quality have intensified seizure frequency and disease progression compared to their well-rested counterparts. A better understanding of the complex relationship between sleep and epilepsy is needed, since approximately 20% of seizures and more than 90% of sudden unexpected deaths in epilepsy occur during sleep. Emerging studies suggest that neuroinflammation, (e.g., the CNS immune response characterized by the change in expression of inflammatory mediators and glial activation) may be a potential link between sleep deprivation and seizures. Here, we review the mechanisms by which sleep deprivation induces neuroinflammation and propose that neuroinflammation synergizes with seizure activity to worsen neurodegeneration in the epileptic brain. Additionally, we highlight the relevance of sleep interventions, often overlooked by physicians, to manage seizures, prevent epilepsy-related mortality, and improve quality of life.

Circulating miRNAs as Potential Biomarkers Distinguishing Relapsing-Remitting from Secondary Progressive Multiple Sclerosis. A Review

Multiple sclerosis (MS) is a debilitating neurodegenerative, highly heterogeneous disease with a variable course. The most common MS subtype is relapsing–remitting (RR), having interchanging periods of worsening and relative stabilization. After a decade, in most RR patients, it alters into the secondary progressive (SP) phase, the most debilitating one with no clear remissions, leading to progressive disability deterioration. Among the greatest challenges for clinicians is understanding disease progression molecular mechanisms, since RR is mainly characterized by inflammatory processes, while in SP, the neurodegeneration prevails. This is especially important because distinguishing RR from the SP subtype early will enable faster implementation of appropriate treatment. Currently, the MS course is not well-correlated with the biomarkers routinely used in clinical practice. Despite many studies, there are still no reliable indicators correlating with the disease stage and its activity degree. Circulating microRNAs (miRNAs) may be considered valuable molecules for the MS diagnosis and, presumably, helpful in predicting disease subtype. MiRNA expression dysregulation is commonly observed in the MS course. Moreover, knowledge of diverse miRNA panel expression between RRMS and SPMS may allow for deterring disability progression through successful treatment. Therefore, in this review, we address the current state of research on differences in miRNA panel expression between the phases.

Regulation of P-glycoprotein by miR-27a-3p at the Brain Endothelial Barrier

Multi-drug resistance P-glycoprotein (P-gp/MDR1) is one of the most clinically relevant ABC transporters, highly enriched at the blood-brain barrier (BBB) with a broad substrate spectrum including therapeutic drugs and metabolic waste products. Altered P-gp transport function has been implicated in multi-drug resistance and in the pathogenesis and progression of neurological diseases. Recent studies have shown that P-gp expression is modulated by micro-RNAs in peripheral organs. Particularly, miR-27a-3p has been shown to play a critical role in the regulation of P-gp in multi-drug resistant cancer cells. In brain disorders, altered levels of miR-27a-3p were reported in several diseases associated with alterations in P-gp expression at the BBB. However, effect of altered miR-27a-3p expression on P-gp expression at the BBB remains to be determined. In this study, we investigated the role of miR-27a-3p in the regulation of P-gp expression and activity at the brain endothelium. Levels of miR-27a-3p were modulated by mimic and inhibitor transfection in an in-vitro model of human brain endothelial hCMEC/D3 cells. Effect of miR-27a-3p modulation on P-gp expression and activity was examined and the underlying regulatory mechanisms explored. Our results showed that transfection of hCMEC/D3 cells with miR-27a-3p mimic induces expression and activity of P-gp while miR-27a-3p inhibition exerted opposite effects. Mechanistic studies revealed that miR-27a-3p regulates P-gp by mediating Glycogen Synthase Kinase 3 Beta (GSK3ß) inhibition and activating Wnt/ß-catenin signaling. These findings shed light on miR-27a-3p/GSK3ß/ß-catenin as a novel axis that could be exploited to modulate P-gp efflux activity at the brain endothelium and help improving CNS diseases treatment or brain protection.

Comprehensive analysis of hub mRNA, lncRNA and miRNA, and associated ceRNA networks implicated in grass carp (Ctenopharyngodon idella) growth traits

Grass carp (Ctenopharyngodon idella) is the most productive freshwater aquaculture fish in worldwide. However, the molecular mechanism of its growth traits has not been fully elucidated. Whole transcriptome analysis of the brain and hepatopancreas of 29 six-month-old grass carp with different growth rates was performed. Weighted gene co-expression network analysis (WGCNA) was used to construct a weighted gene co-expression network of mRNA, miRNA and lncRNA separately. A total of 35 hub mRNAs, 47 hub lncRNAs and 33 hub miRNAs were identified from the brain, 37 hub mRNAs, 110 hub lncRNAs and 36 hub miRNAs were identified from the hepatopancreas. The ceRNA networks in the brain and hepatopancreas were involved in brain development and nutrient metabolism, respectively. Overall, this is the first investigation of the growth-related transcriptomic characteristics in the brain and hepatopancreas of grass carp, thus will help us to further explore the molecular mechanism of grass carp growth rate.

Overexpression of miR-133b protects against isoflurane-induced learning and memory impairment

A number of microRNAs (miRs) have been identified as being involved in the regulation of anesthesia-induced cognitive impairment. The aim of the present study was to investigated the role and potential mechanism of miR-133b in isoflurane-induced learning and memory impairment. An animal model of isoflurane exposure was established using neonatal Sprague-Dawley rats. The rats were trained for Morris water maze (MWM) testing to assess their spatial learning and memory ability. Reverse transcription-quantitative polymerase chain reaction was used for the measurement of miR-133b expression in hippocampal tissues and primary hippocampal neuron cultures. Cell viability was assessed using a Cell Counting Kit-8 assay, and flow cytometric analysis was used to determine the rate of apoptosis. The MWM test results indicated that during the training period, the time required to locate the platform was significantly increased for rats exposed to isoflurane, and this increased time was reduced by the overexpression of miR-133b. The results of a probe trial indicated that isoflurane exposure increased escape latency and decreased the time spent in the platform area for isoflurane-treated rats; however, these effects were reversed by the injection of miR-133b agomir. The in vitro experiments demonstrated that the overexpression of miR-133b attenuated the reduction of neuronal cell viability induced by isoflurane, and inhibited the isoflurane-induced apoptosis of hippocampal neurons. In conclusion, the present study revealed that the overexpression of miR-133b attenuated isoflurane-induced learning and memory impairment in rats. Furthermore, miR-133b overexpression promoted the viability of hippocampal neurons and their resistance to apoptosis when exposed to isoflurane.

An Insight into the microRNAs Associated with Arteriovenous and Cavernous Malformations of the Brain

Background: Brain arteriovenous malformations (BAVMs) and cerebral cavernous malformations (CCMs) are rare developmental anomalies of the intracranial vasculature, with an irregular tendency to rupture, and as of yet incompletely deciphered pathophysiology. Because of their variety in location, morphology, and size, as well as unpredictable natural history, they represent a management challenge. MicroRNAs (miRNAs) are strands of non-coding RNA of around 20 nucleotides that are able to modulate the expression of target genes by binding completely or partially to their respective complementary sequences. Recent breakthroughs have been made on elucidating their contribution to BAVM and CCM occurrence, growth, and evolution; however, there are still countless gaps in our understanding of the mechanisms involved. Methods: We have searched the Medline (PubMed; PubMed Central) database for pertinent articles on miRNAs and their putative implications in BAVMs and CCMs. To this purpose, we employed various permutations of the terms and idioms: ‘arteriovenous malformation’, ‘AVM’, and ‘BAVM’, or ‘cavernous malformation’, ‘cavernoma’, and ‘cavernous angioma’ on the one hand; and ‘microRNA’, ‘miRNA’, and ‘miR’ on the other. Using cross-reference search; we then investigated additional articles concerning the individual miRNAs identified in other cerebral diseases. Results: Seven miRNAs were discovered to play a role in BAVMs, three of which were downregulated (miR-18a, miR-137, and miR-195*) and four upregulated (miR-7-5p, miR-199a-5p, miR-200b-3p, and let-7b-3p). Similarly, eight miRNAs were identified in CCM in humans and experimental animal models, two being upregulated (miR-27a and mmu-miR-3472a), and six downregulated (miR-125a, miR-361-5p, miR-370-3p, miR-181a-2-3p, miR-95-3p, and let-7b-3p). Conclusions: The following literature review endeavored to address the recent discoveries related to the various implications of miRNAs in the formation and growth of BAVMs and CCMs. Additionally, by presenting other cerebral pathologies correlated with these miRNAs, it aimed to emphasize the potential directions of upcoming research and biological therapies.

MiR-27a-3p suppresses cerebral ischemia-reperfusion injury by targeting FOXO1

Cerebral ischemia-reperfusion (CI/R) injury is a serious complication when treating patients experiencing ischemic stroke. Although the microRNA miR-27a-3p reportedly participates in ischemia/reperfusion (I/R) injury, its actions in CI/R remain unclear. To mimic CI/R in vitro, HT22 cells were subjected to oxygen glucose deprivation/reoxygenation (OGD/R). The results indicate that OGD inhibited growth and induced apoptosis among HT22 cells. The apoptosis was accompanied by increases in activated caspases 3 and 9 and decreases in Bcl-2. Oxidative stress was also increased, as indicated by increases in ROS and malondialdehyde and decreases in glutathione and superoxide dismutase. In addition, OGD induced G1 arrest in HT22 cells with corresponding upregulation of FOXO1 and p27 Kip1, suggesting the cell cycle arrest was mediated by FOXO1/p27 Kip1 signaling. Notably, FOXO1 was found to be the direct target of miR-27a-3p in HT22 cells. MiR-27a-3p was downregulated in OGD/R-treated HT22 cells, and miR-27a-3p mimics partially or entirely reversed all of the in vitro effects of OGD. Moreover, miR-27a-3p agomir significantly alleviated the symptoms of CI/R in vivo in a rat model of CI/R. Thus, MiR-27a-3p appears to suppress CI/R injury by targeting FOXO1.

MicroRNA Dysregulation in Epilepsy: From Pathogenetic Involvement to Diagnostic Biomarker and Therapeutic Agent Development

Epilepsy is the result of a group of transient abnormalities in brain function caused by an abnormal, highly synchronized discharge of brain neurons. MicroRNA (miRNA) is a class of endogenous non-coding single-stranded RNA molecules that participate in a series of important biological processes. Recent studies demonstrated that miRNAs are involved in a variety of central nervous system diseases, including epilepsy. Although the exact mechanism underlying the role of miRNAs in epilepsy pathogenesis is still unclear, these miRNAs may be involved in the inflammatory response in the nervous system, neuronal necrosis and apoptosis, dendritic growth, synaptic remodeling, glial cell proliferation, epileptic circuit formation, impairment of neurotransmitter and receptor function, and other processes. Here, we discuss miRNA metabolism and the roles of miRNA in epilepsy pathogenesis and evaluate miRNA as a potential new biomarker for the diagnosis of epilepsy, which enhances our understanding of disease processes.

MicroRNA expression profiling after recurrent febrile seizures in rat and emerging role of miR-148a-3p/SYNJ1 axis

Febrile seizures (FSs) are common neurological disorders in both infants and children, although the precise underlying mechanism remains to be explored, especially in the expression pattern and function of microRNAs (miRNAs). In this report, we aimed to screen new potential miRNAs and examine the role of miR-148a-3p in hippocampal neurons in FS rats via Synaptojanin-1 (SYNJ1). Thirty rats were randomly divided into the normal and FS model groups, which were investigated by miRNA array. This process identified 31 differentially expressed (20 upregulated and 11 downregulated) miRNAs and potential miRNA target genes. In addition, hippocampal neurons were assigned into five groups for different transfections. Apoptosis was detected by TUNEL and flow cytometry. SYNJ1 was identified as a target gene of miR-148-3p. In vitro experiments revealed that inhibition of miR-148a-3p decreased neuronal cell apoptosis. Moreover, overexpression of miR-148a-3p resulted in activation of PI3K/Akt signaling pathway and the apoptosis of hippocampal neurons. MiR-148a-3p inhibitor could reverse the above events. Taken together, our data demonstrated that the hippocampal miRNA expression profiles of a rat model of FS provide a large database of candidate miRNAs and neuron-related target genes. Furthermore, miR-148a-3p acted as a apoptosis enhcaner via the activation of the SYNJ1/PI3K/Akt signaling pathway, highlighting a potential therapeutic target in the treatment of infants with hyperthermia-induced brain injury.

miR-124-3p Ameliorates Isoflurane-Induced Learning and Memory Impairment via Targeting STAT3 and Inhibiting Neuroinflammation

INTRODUCTION

Substantial evidence has indicated that isoflurane leads to learning and memory impairment. This study was designed to investigate the potential role of microRNA-124-3p (miR-124-3p) in isoflurane-induced learning and memory impairment in rats.

METHODS

Spatial learning and memory of rats were estimated by the Morris water maze (MWM) test after the construction of isoflurane-treated models. qRT-PCR was performed to assess the expression levels of miR-124-3p. The levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α in the hippocampal tissues were determined by enzyme-linked immunosorbent assay. The luciferase activity was determined by using a dual-luciferase reporter assay system.

RESULTS

The higher escape latency and lower time spent in the original quadrant were shown in isoflurane-treated rats compared with the control rats. Moreover, treatment with isoflurane could induce neuroinflammation, and miR-124-3p was poorly expressed in the hippocampal tissue of isoflurane-treated rats. Furthermore, STAT3 is a functional target of miR-124-3p, and inflammatory cytokine level was downregulated by miR-124-3p.

DISCUSSION/CONCLUSION

Combining the results of the current study demonstrates that miR-124-3p may have pivotal roles in improving isoflurane-induced learning and memory impairment via targeting STAT3 and inhibiting neuroinflammation.

Inhibition of miR-181a-5p reduces astrocyte and microglia activation and oxidative stress by activating SIRT1 in immature rats with epilepsy

MicroRNAs regulate gene expression at the posttranscriptional level, and this process has been shown to be implicated in the pathological processes of temporal lobe epilepsy. At present, studies about the impact of microRNA-181a (miR-181a) on epilepsy have focused on hippocampal neurons, and the effect of miR-181a on other cells in the hippocampus remains poorly understood. Herein, we explored the role of miR-181a-5p in a lithium-pilocarpine model of epilepticus in immature rats. We found that the hippocampal expression level of miR-181a-5p was increased. Inhibition of miR-181a-5p protected the hippocampus against epilepsy, including hippocampal insults, neuronal apoptosis, astrocyte and microglia activation, neuroinflammation, oxidative stress, mitochondrial function, and cognitive dysfunction. Moreover, miR-181a-5p inhibition exerted a seizure-suppressing effect via SIRT1 upregulation. Overall, our findings reveal the potential role of the miR-181a-5p/SIRT1 pathway in the development of temporal lobe epilepsy, and this pathway may represent a novel target for ameliorating epilepsy and its sequelae.

Long Noncoding RNA SOX2-OT Exacerbates Hypoxia-Induced Cardiomyocytes Injury by Regulating miR-27a-3p/TGFβR1 Axis

Background

Myocardial infarction (MI) was a severe cardiovascular disease resulted from acute, persistent hypoxia, or ischemia condition. Additionally, MI generally led to heart failure, even sudden death. A multitude of research studies proposed that long noncoding RNAs (lncRNAs) frequently participated in the regulation of heart diseases. The specific function and molecular mechanism of SOX2-OT in MI remained unclear. Aim of the Study. The current research was aimed to explore the role of SOX2-OT in MI.

Methods

Bioinformatics analysis (DIANA tools and Targetscan) and a wide range of experiments (CCK-8, flow cytometry, RT-qPCR, luciferase reporter, RIP, caspase-3 activity, trans-well, and western blot assays) were adopted to investigate the function and mechanism of SOX2-OT.

Results

We discovered that hypoxia treatment decreased cell viability but increased cell apoptosis. Besides, lncRNA SOX2-OT expression was upregulated in hypoxic HCMs. Hereafter, we confirmed that SOX2-OT could negatively regulate miR-27a-3p levels by directly binding with miR-27a-3p, and miR-27a-3p also could negatively regulate SOX2-OT levels. Furthermore, knockdown of SOX2-OT promoted cell proliferation, migration, and invasion, but limited cell apoptosis. However, these effects were reversed by anti-miR-27a-5p. Besides, we verified that miR-27a-3p binding with the 3′UTR of TGFBR1 and SOX2-OT regulated TGFβR1 level by collaborating with miR-27a-3p in HCMs. Eventually, rescue assays validated that the influence of SOX2-OT silence or miR-27a-3p overexpression on cellular processes in cardiomyocytes injury was counteracted by TGFBR1 overexpression.

Conclusions

Long noncoding RNA SOX2-OT exacerbated hypoxia-induced cardiomyocytes injury by regulating miR-27a-3p/TGFβR1 axis, which may provide a novel insight for heart failure treatment.