MicroRNAs: A Light into the “Black Box” of Neuropediatric Diseases?

Focus on MicroRNAs as Biomarker in Pediatric Diseases

BACKGROUND

MiRNAs are a class of small non-coding RNAs that are involved in the post-transcriptional regulation of gene expression. MiRNAs are considered a class of epigenetic biomarkers. These biomarkers can investigate disease at different stages: diagnosis, therapy or clinical follow-up.

OBJECTIVE

The aim of this paper is to highlight the innovative use of miRNAs in several childhood diseases.

METHODS

We conducted a literature review to search the usage of miRNAs in pediatric clinical routine or experimental trials.

RESULTS

We found a possible key role of miRNAs in different pediatric illnesses (metabolic alterations, coagulation defects, cancer).

CONCLUSION

The modest literature production denotes that further investigation is needed to assess and validate the promising role of miRNAs as non-invasive biomarkers in pediatric disorders.

The Challenge of microRNA as a Biomarker of Epilepsy

BACKGROUND

Epilepsy is one of chronic severe neurological disorders possess to recurring seizures. And now anti-epileptic drugs are only effective in less than one third of epilepsy patients, and biomarkers predicting are not available when the specific antiepileptic drugs treated. Advanced studies have showed that miRNA may be a key in the pathogenesis of epilepsy beginning in the early 2000 years. Several target genes and pathways of miRNA which related to the therapeutic methods to epilepsy.

METHOD

We searched PubMed from Jan 1,2000 to Jan 1, 2017, using the terms "epilepsy AND microRNA AND biomarker" and "seizure AND microRNA AND biomarker". We selected articles that featured novel miRNAs in vivo epilepsy models and patients. We then selected the most relevant articles based on a subjective appraisal of their quality and mechanistic insight that could be relevant to epilepsy.

RESULTS

Decrease the expression of has-miR134 could be a potential non-invasive biomarker to use in diagnosis for the epilepsy patients for using hsa-miR-134 also be identified to distinguish patients with and without epilepsy. miR-181a show significant downregulation in the acute stage, but up regulation in the chronic stage and in the latent stage there is no changing and how about this phenomenon appearance in different stage still should be discussed in the future. Besides that, miR- 146a can down-regulated in the patients using genome-wide for serum in circulating miRNAs.miR- 124, miR-199a, and miR-128 etc. could be a candidate for the biomarker in future. miR-15a-5p and -194-5p down-regulated in epilepsy patients, in the future, it may be used as a novel biomarker for improve diagnosis.

CONCLUSION

These observations give a chance that new development for diagnosis and treatment of epilepsy patients. Advanced technique and miRNA combination may product more effective roles in epilepsy and other disease. These reports will be available to solve the application of miRNAs as biomarkers and novel therapy approaches for epilepsy. In summary, researcher who focus on miRNAs should be understanding of the causes, treatment, and diagnosis of epilepsy. exploration of any of these effects on the efficacy of these drugs is worthwhile.

Expression and Regulatory Network Analysis of miR-140-3p, a New Potential Serum Biomarker for Autism Spectrum Disorder

Given its prevalence and social impact, Autism Spectrum Disorder (ASD) is drawing much interest. Molecular basis of ASD is heterogeneous and only partially known. Many factors, including disorders comorbid with ASD, like TS (Tourette Syndrome), complicate ASD behavior-based diagnosis and make it vulnerable to bias. To further investigate ASD etiology and to identify potential biomarkers to support its precise diagnosis, we used TaqMan Low Density Array technology to profile serum miRNAs from ASD, TS, and TS+ASD patients, and unaffected controls (NCs). Through validation assays in 30 ASD, 24 TS, and 25 TS+ASD patients and 25 NCs, we demonstrated that miR-140-3p is upregulated in ASD vs.: NC, TS, and TS+ASD (Tukey's test, p-values = 0.03, = 0.01, < 0.0001, respectively). ΔCt values for miR-140-3p and YGTSS (Yale Global Tic Severity Scale) scores are positively correlated (Spearman r = 0.33; Benjamini-Hochberg p = 0.008) and show a linear relationship (p = 0.002). Network functional analysis showed that nodes controlled by miR-140-3p, especially CD38 and NRIP1 which are its validated targets, are involved in processes convergingly dysregulated in ASD, such as synaptic plasticity, immune response, and chromatin binding. Biomarker analysis proved that serum miR-140-3p can discriminate among: (1) ASD and NC (Area under the ROC curve, AUC: 0.70; sensitivity: 63.33%; specificity: 68%); (2) ASD and TS (AUC: 0.72; sensitivity: 66.66%; specificity: 70.83%); (3) ASD and TS+ASD (AUC: 0.78; sensitivity: 73.33%; specificity: 76%). Characterization of miR-140-3p network would contribute to further clarify ASD etiology. Serum miR-140-3p could represent a potential non-invasive biomarker for ASD, easy to test through liquid biopsy.

Pathogenesis of cerebral palsy through the prism of immune regulation of nervous tissue homeostasis: literature review

BACKGROUND

The cerebral palsy is highly actual issue of pediatrics, causing significant neurological disability. Though the great progress in the neuroscience has been recently achieved, the pathogenesis of cerebral palsy is still poorly understood.

METHODS

In this work, we reviewed available experimental and clinical data concerning the role of immune cells in pathogenesis of cerebral palsy. Maintaining of homeostasis in nervous tissue and its transformation in case of periventricular leukomalacia were analyzed.

RESULTS

The reviewed data demonstrate involvement of immune regulatory cells in the formation of nervous tissue imbalance and chronicity of inborn brain damage. The supported opinion, that periventricular leukomalacia is not a static phenomenon, but developing process, encourages our optimism about the possibility of its correction.

CONCLUSIONS

The further studies of changes of the nervous and immune systems in cerebral palsy are needed to create fundamentally new directions of the specific therapy and individual schemes of rehabilitation.

Changes in microglial inflammation-related and brain-enriched MicroRNAs expressions in response to in vitro oxygen-glucose deprivation

Microglia plays important role in central nervous system immune surveillance and has emerged as an essential cellular component for understanding brain diseases. MicroRNAs (miRs) are small, noncoding RNAs that regulate the post-transcriptional expression of protein-coding mRNAs, which may have key roles in microglial activation in response to brain ischemia and other stressors. Primary cultured rat microglial cells were prepared, and then microglial activation model was established by oxygen-glucose deprivation (OGD) method. Morphological observation, CD11b/c immunofluorence, MTT assay and Propidium iodide staining were done to test microglia viability at different OGD time points (0, 5, 10, 15, 30, 60 min). qPCR were performed to detect the dynamic changes in expressions of inflammation-related miRs (146a, 21, 181a, 221, and 222) and brain-enriched miRs (124, 134, 9, 132, and 138) in resting microglia and after challenge with OGD for the same time points. The activation and viability of the microglia was time dependent. Similarly, expressions of different miRs in microglia were significantly upregulated and reached the peak at different time points before reaching the baseline level with extension of OGD. Our data demonstrates for the first time that OGD as a model of an ischemic insult modulates the expressions of some inflammation-related and brain-enriched miRs. These changes may help to explore the molecular basis of microglia activation on the post-transcriptional level in response to different time points of OGD.

Effects of MRP8, LPS, and lenalidomide on the expressions of TNF-α , brain-enriched, and inflammation-related microRNAs in the primary astrocyte culture

Astrocytes are now recognized as a heterogeneous class of cells with many important and diverse functions in healthy and diseased central nervous system (CNS). MicroRNAs (miRNAs) are small, noncoding RNAs which may have key roles in astrocytes activation in response to various stimuli. We performed quantitative real-time PCR (qPCR) to detect changes in the expressions of brain-enriched miRNAs (124, 134, 9, 132, and 138), inflammation-related miRNAs (146a, 21, 181a, 221, and 222), and tumor necrosis factor alpha (TNF- α ) in the rat primary astrocyte cultures after stimulation with myeloid-related protein 8 (MRP8) and lipopolysaccharides (LPS). Further, we inhibited the expression of TNF- α in the astrocytes by using TNF- α inhibitor (lenalidomide) and tested for the first time the effect of this inhibition on the expressions of the same tested miRNAs. Stimulation of the astrocytes with MRP8 or LPS leads to significant upregulation of miRNAs (124, 134, 9, 132, 146a, 21, 181a, 221, and 222), while miRNA-138 was downregulated. TNF- α inhibition with lenalidomide leads to opposite expressions of the tested miRNAs. These miRNAs may play an important role in activation of the astrocytes and may be a novel target for cell-specific therapeutic interventions in multiple CNS diseases.

MicroRNAs: new insights into chronic childhood diseases

Chronic diseases are the major cause of morbidity and mortality worldwide and have shown increasing incidence rates among children in the last decades. Chronic illnesses in the pediatric population, even if well managed, affect social, psychological, and physical development and often limit education and active participation and increase the risk for health complications. The significant pediatric morbidity and mortality rates caused by chronic illnesses call for serious efforts toward better understanding of the pathogenesis of these disorders. Recent studies have shown the involvement of microRNAs (miRNAs) in various aspects of major pediatric chronic non-neoplastic diseases. This review focuses on the role of miRNAs in four major pediatric chronic diseases including bronchial asthma, diabetes mellitus, epilepsy and cystic fibrosis. We intend to emphasize the importance of miRNA-based research in combating these major disorders, as we believe this approach will result in novel therapies to aid securing normal development and to prevent disabilities in the pediatric population.

Expressions of tumor necrosis factor alpha and microRNA-155 in immature rat model of status epilepticus and children with mesial temporal lobe epilepsy

Recently, the role of inflammation has attracted great attention in the pathogenesis of mesial temporal lobe epilepsy (MTLE), and microRNAs start to emerge as promising new players in MTLE pathogenesis. In this study, we investigated the dynamic expression patterns of tumor necrosis factor alpha (TNF-α) and microRNA-155 (miR-155) in the hippocampi of an immature rat model of status epilepticus (SE) and children with MTLE. The expressions of TNF-α and miR-155 were significantly upregulated in the seizure-related acute and chronic stages of MTLE in the immature rat model and also in children with MTLE. Modulation of TNF-α expression, either by stimulation using myeloid-related protein (MRP8) or lipopolysaccharide or inhibition using lenalidomide on astrocytes, leads to similar dynamic changes in miR-155 expression. Our study is the first to focus on the dynamic expression pattern of miR-155 in the immature rat of SE lithium-pilocarpine model and children with MTLE and to detect their relationship at the astrocyte level. TNF-α and miR-155, having similar expression patterns in the three stages of MTLE development, and their relationship at the astrocyte level may suggest a direct interactive relationship during MTLE development. Therefore, modulation of the TNF-α/miR-155 axis may be a novel therapeutic target for the treatment of MTLE.

microRNA s (9, 138, 181A, 221, and 222) and mesial temporal lobe epilepsy in developing brains

Background: Recently, microRNAs (miRNAs) have attracted much attention as novel players in the pathogenesis of mesial temporal lobe epilepsy (MTLE) in mature and developing brains. This study aimed to investigate the expression dynamics of miR-9, miR-138, miR-181a, miR-221, and miR-222 in the hippocampus of an immature rat model during the three stages of MTLE development and in children with MTLE. Methodology: qPCR was used to measure expression levels during the three stages of MTLE development (2 h, 3, and 8 weeks after induction of lithium-pilocarpine status epilepticus, representing the acute, latent, and chronic stages, respectively. Expression levels were also measured in hippocampi obtained from children with MTLE and normal controls. Results: In the rat model, miR-9 was significantly upregulated during the acute and chronic stages relative to controls, but not during the latent stage. MiR-138, miR-221 and miR-222 were all downregulated during all three stages of MTLE development. MiR-181a was downregulated during the acute stage, upregulated during the chronic stage, and unaltered during the latent stage. In children, miR-9 and miR-181a were upregulated, while miR-138, miR-221, and miR-222 were downregulated. Conclusion: Modulation of these miRNAs may be a new strategy in designing antiepileptic and anticonvulsant therapies for the developing brain.