MicroRNA in Brain pathology: Neurodegeneration the Other Side of the Brain Cancer

Variances in the Expression Profile of Circadian Clock-Related Genes in Astrocytic Brain Tumors

This study explores the role of circadian clock genes in the progression of astrocytic tumors, a prevalent type of brain tumor. The aim was to assess the expression patterns of these genes in relation to the tumor grade. Using microarray analysis, qRT-PCR, and methylation-specific PCR, we examined gene expression, DNA methylation patterns, and microRNA interactions in tumor samples from 60 patients. Our results indicate that the expression of key circadian clock genes, such as clock circadian regulator (CLOCK), protein kinase AMP-activated catalytic subunit alpha 1 (PRKAA1), protein kinase AMP-activated catalytic subunit alpha 2 (PRKAA2), protein kinase AMP-activated non-catalytic subunit beta 1 (PRKAB1), protein kinase AMP-activated non-catalytic subunit beta 2 (PRKAB2), period circadian regulator 1 (PER1), period circadian regulator 2 (PER2) and period circadian regulator 3 (PER3), varies significantly with the tumor grade. Notably, increased CLOCK gene expression and protein levels were observed in higher-grade tumors. DNA methylation analysis revealed that the promoter regions of PER1-3 genes were consistently methylated, suggesting a mechanism for their reduced expression. Our findings also underscore the complex regulatory mechanisms involving miRNAs, such as hsa-miR-106-5p, hsa-miR-20b-5p, and hsa-miR-30d-3p, which impact the expression of circadian clock-related genes. This underscores the importance of circadian clock genes in astrocytic tumor progression and highlights their potential as biomarkers and therapeutic targets. Further research is needed to validate these results and explore their clinical implications.

Bioinformatics and Systems Biology Approaches to Identify the Synergistic Effects of Alcohol Use Disorder on the Progression of Neurological Diseases

Clinical investigations showed that individuals with Alcohol Use Disorder (AUD) have worse Neurological Disease (ND) development, pointing to possible pathogenic relationships between AUD and NDs. It remains difficult to identify risk factors that are predisposing between AUD and NDs. In order to fix these issues, we created the bioinformatics pipeline and network-based approaches for employing unbiased methods to discover genes abnormally stated in both AUD and NDs and to pinpoint some of the common molecular pathways that might underlie AUD and ND interaction. We found 100 differentially expressed genes (DEGs) in both the AUD and ND patient's tissue samples. The most important Gene Ontology (GO) terms and metabolic pathways, including positive control of cytotoxicity caused by T cells, proinflammatory responses, antigen processing and presentation, and platelet-triggered interactions with vascular and circulating cell pathways were then extracted using the overlapped DEGs. Protein-protein interaction analysis was used to identify hub proteins, including CCL2, IL1B, TH, MYCN, HLA-DRB1, SLC17A7, and HNF4A, in the pathways that have been reported as playing a function in these disorders. We determined several TFs (HNF4A, C4A, HLA-B, SNCA, HLA-DMB, SLC17A7, HLA-DRB1, HLA-C, HLA-A, and HLA-DPB1) and potential miRNAs (hsa-mir-34a-5p, hsa-mir-34c-5p, hsa-mir-449a, hsa-mir-155-5p, and hsa-mir-1-3p) were crucial for regulating the expression of AUD and ND which could serve as prospective targets for treatment. Our methodologies discovered unique putative biomarkers that point to the interaction between AUD and various neurological disorders, as well as pathways that could one day be the focus of therapeutic intervention.

MiR-128-3p - a gray eminence of the human central nervous system

MicroRNA-128-3p (miR-128-3p) is a versatile molecule with multiple functions in the physiopathology of the human central nervous system. Perturbations of miR-128-3p, which is enriched in the brain, contribute to a plethora of neurodegenerative disorders, brain injuries, and malignancies, as this miRNA is a crucial regulator of gene expression in the brain, playing an essential role in the maintenance and function of cells stemming from neuronal lineage. However, the differential expression of miR-128-3p in pathologies underscores the importance of the balance between its high and low levels. Significantly, numerous reports pointed to miR-128-3p as one of the most depleted in glioblastoma, implying it is a critical player in the disease's pathogenesis and thus may serve as a therapeutic agent for this most aggressive form of brain tumor. In this review, we summarize the current knowledge of the diverse roles of miR-128-3p. We focus on its involvement in the neurogenesis and pathophysiology of malignant and neurodegenerative diseases. We also highlight the promising potential of miR-128-3p as an antitumor agent for the future therapy of human cancers, including glioblastoma, and as the linchpin of brain development and function, potentially leading to the development of new therapies for neurological conditions.

A Machine Learning Approach for Highlighting microRNAs as Biomarkers Linked to Amyotrophic Lateral Sclerosis Diagnosis and Progression

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive loss of motor neurons in the brain and spinal cord. The early diagnosis of ALS can be challenging, as it usually depends on clinical examination and the exclusion of other possible causes. In this regard, the analysis of miRNA expression profiles in biofluids makes miRNAs promising non-invasive clinical biomarkers. Due to the increasing amount of scientific literature that often provides controversial results, this work aims to deepen the understanding of the current state of the art on this topic using a machine-learning-based approach. A systematic literature search was conducted to analyze a set of 308 scientific articles using the MySLR digital platform and the Latent Dirichlet Allocation (LDA) algorithm. Two relevant topics were identified, and the articles clustered in each of them were analyzed and discussed in terms of biomolecular mechanisms, as well as in translational and clinical settings. Several miRNAs detected in the tissues and biofluids of ALS patients, including blood and cerebrospinal fluid (CSF), have been linked to ALS diagnosis and progression. Some of them may represent promising non-invasive clinical biomarkers. In this context, future scientific priorities and goals have been proposed.

Circulating and extracellular vesicle-derived microRNAs as biomarkers in bone-related diseases

MicroRNAs (miRNA) are small non-coding RNA molecules that regulate posttranscriptional gene expression by repressing messengerRNA-targets. MiRNAs are abundant in many cell types and are secreted into extracellular fluids, protected from degradation by packaging in extracellular vesicles. These circulating miRNAs are easily accessible, disease-specific and sensitive to small changes, which makes them ideal biomarkers for diagnostic, prognostic, predictive or monitoring purposes. Specific miRNA signatures can be reflective of disease status and development or indicators of poor treatment response. This is especially important in malignant diseases, as the ease of accessibility of circulating miRNAs circumvents the need for invasive tissue biopsy. In osteogenesis, miRNAs can act either osteo-enhancing or osteo-repressing by targeting key transcription factors and signaling pathways. This review highlights the role of circulating and extracellular vesicle-derived miRNAs as biomarkers in bone-related diseases, with a specific focus on osteoporosis and osteosarcoma. To this end, a comprehensive literature search has been performed. The first part of the review discusses the history and biology of miRNAs, followed by a description of different types of biomarkers and an update of the current knowledge of miRNAs as biomarkers in bone related diseases. Finally, limitations of miRNAs biomarker research and future perspectives will be presented.

Recent Advances in the Roles of MicroRNA and MicroRNA-Based Diagnosis in Neurodegenerative Diseases

Neurodegenerative diseases manifest as progressive loss of neuronal structures and their myelin sheaths and lead to substantial morbidity and mortality, especially in the elderly. Despite extensive research, there are few effective treatment options for the diseases. MicroRNAs have been shown to be involved in the developmental processes of the central nervous system. Mounting evidence suggest they play an important role in the development of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. However, there are few reviews regarding the roles of miRNAs in neurodegenerative diseases. This review summarizes the recent developments in the roles of microRNAs in neurodegenerative diseases and presents the application of microRNA-based methods in the early diagnosis of these diseases.

miR-142 Targets TIM-1 in Human Endothelial Cells: Potential Implications for Stroke, COVID-19, Zika, Ebola, Dengue, and Other Viral Infections

T-cell immunoglobulin and mucin domain 1 (TIM-1) has been recently identified as one of the factors involved in the internalization of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in human cells, in addition to angiotensin-converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2), neuropilin-1, and others. We hypothesized that specific microRNAs could target TIM-1, with potential implications for the management of patients suffering from coronavirus disease 2019 (COVID-19). By combining bioinformatic analyses and functional assays, we identified miR-142 as a specific regulator of TIM-1 transcription. Since TIM-1 has been implicated in the regulation of endothelial function at the level of the blood-brain barrier (BBB) and its levels have been shown to be associated with stroke and cerebral ischemia-reperfusion injury, we validated miR-142 as a functional modulator of TIM-1 in human brain microvascular endothelial cells (hBMECs). Taken together, our results indicate that miR-142 targets TIM-1, representing a novel strategy against cerebrovascular disorders, as well as systemic complications of SARS-CoV-2 and other viral infections.

Delivering the Promise of Gene Therapy with Nanomedicines in Treating Central Nervous System Diseases

Central Nervous System (CNS) diseases, such as Alzheimer's diseases (AD), Parkinson's Diseases (PD), brain tumors, Huntington's disease (HD), and stroke, still remain difficult to treat by the conventional molecular drugs. In recent years, various gene therapies have come into the spotlight as versatile therapeutics providing the potential to prevent and treat these diseases. Despite the significant progress that has undoubtedly been achieved in terms of the design and modification of genetic modulators with desired potency and minimized unwanted immune responses, the efficient and safe in vivo delivery of gene therapies still poses major translational challenges. Various non-viral nanomedicines have been recently explored to circumvent this limitation. In this review, an overview of gene therapies for CNS diseases is provided and describes recent advances in the development of nanomedicines, including their unique characteristics, chemical modifications, bioconjugations, and the specific applications that those nanomedicines are harnessed to deliver gene therapies.

Mechanisms and Biomarker Potential of Extracellular Vesicles in Stroke

Simple Summary

A stroke occurs when there is a lack of blood flow to the brain. Stroke injures the brain and can have devastating outcomes depending on the size and location of the brain tissue affected. Currently, there are only a limited number of treatment options for stroke. Extracellular vesicles are small vesicles secreted by cells. Importantly, extracellular vesicles have specific markers indicating the cell they were released from and can pass from the brain into the blood. For these reasons, assessing extracellular vesicles in the blood may create a window into changes occurring in the brain. Assessing changes in extracellular vesicles in the blood during stroke may produce new insight into the cellular changes in the brain causing injury during stroke. This in turn may generate potential targets for the development of future treatments. We summarize what is known about changes in brain-cell-specific extracellular vesicles during stroke and stress the importance of continuing to study these changes.

Abstract

Stoke is a prevalent and devastating neurologic condition with limited options for therapeutic management. Since brain tissue is rarely accessible clinically, peripheral biomarkers for the central nervous system’s (CNS’s) cellular response to stroke may prove critical for increasing our understanding of stroke pathology and elucidating novel therapeutic targets. Extracellular vesicles (EVs) are cell-derived, membrane-enclosed vesicles secreted by all cell types within the CNS that can freely pass the blood-brain barrier (BBB) and contain unique markers and content linked to their cell of origin. These unique qualities make brain-derived EVs novel candidates for non-invasive blood-based biomarkers of both cell specificity and cell physiological state during the progression of stroke and recovery. While studies are continuously emerging that are assessing the therapeutic potential of EVs and profiling EV cargo, a vast minority of these studies link EV content to specific cell types. A better understanding of cell-specific EV release during the acute, subacute, and chronic stages of stroke is needed to further elucidate the cellular processes responsible for stroke pathophysiology. Herein, we outline what is known about EV release from distinct cell types of the CNS during stroke and the potential of these EVs as peripheral biomarkers for cellular function in the CNS during stroke.

Exposure to nanographene oxide induces gene expression dysregulation in normal human astrocytes

Objective. Nanographene oxide, an oxidation derivative of graphene, is considered to be one of the nanomaterials attractive for biomedical applications, although this nanomaterial is toxic. The increasing exploitation of graphene-based materials necessitates a comprehensive evaluation of the potential impact of these materials on the human health. Moreover, it is necessary to investigate in detail the mechanisms of its toxic effect on living cells particularly at the genome level. The present study aimed to evaluate the impact of low doses of nanographene oxide on the expression of key regulatory genes in normal human astrocytes.

Methods. Normal human astrocytes, line NHA/TS, were exposed to low doses of nanographene oxide (1 and 4 ng/ml) for 24 h. RNA was extracted from the cells and used for cDNA synthesis. The expression levels of NAMPT, TSPAN13, BCAR3, BRCA1, PTGS2, P4HA1, and P4HA2 mRNAs as well as microRNAs were measured by quantitative polymerase chain reaction.

Results. It was found that the low doses of nanographene oxide induced a dysregulation in the expression of the key regulatory genes in normal human astrocytes in dose-dependent (1 and 4 ng/ml) and gene-specific manner. Nanographene oxide also strongly suppressed the expression of NAMPT, BCAR3, and TSPAN13 genes and significantly up-regulated BRCA1, PTGS2, P4HA1, and P4HA2 ones with a more significant effect in P4HA1 and P4HA2 genes. The expression of miR-96-5p and miR-145-5p was also down-regulated in astrocytes treated with nanographene oxide in a dose-dependent manner.

Conclusion. The data obtained demonstrate that the low doses of nanographene oxide disturbed the genome functions by changing the expression levels of key regulatory genes in gene-specific and dose-dependent manner. Moreover, a higher dose of nanographene oxide induced more pronounced changes in expression of genes indicating for both genotoxic and neurotoxic possible effects in the normal human astrocytes.

Plasma microRNAs as a Potential Biomarker for Identification of Progressive Supranuclear Palsy

Progressive supranuclear palsy (PSP) is the second most common Parkinsonian disorder with complex etiology. The underlying molecular mechanism of PSP pathogenesis remains unclear. The present study aims to find the feasibility of using plasma miRNAs as novel biomarkers. Plasma-focused qPCR panels were used for microRNA profiling and identified differentially expressed microRNAs in PSP compared to controls. The DIANA-miRPath v3.0 was used to perform KEGG pathway analysis. We then confirmed the expression of selected candidates by RT-qPCR and their clinical utility was assessed by ROC analysis. Profiling data revealed 28 differentially expressed microRNAs in PSP. Five overexpressed miRNAs were selected for further analysis. The KEGG pathway analysis revealed 48 high-risk pathways. The study revealed that as a single marker—miR-19b-3p, miR-33a-5p, miR-130b-3p, miR-136-3p, and miR-210-3p had a specificity of 64.71%, 82.35%, 68.75%, 82.35%, and 70.59% at sensitivity 77.78%, 77.78%, 66.67%, 73.33%, and 66.67%, respectively. The result suggests that circulating plasma miRNAs were altered in PSP compared to control. The findings of this study may provide potential biomarkers and pathways associated with PSP. Further large-scale validation studies are required to confirm the same.

The impact of single walled carbon nanotubes on the expression of microRNA in zebrafish (Danio rerio) embryos

Objective. Single-walled carbon nanotubes (SWCNTs) are able to cross the blood-brain barrier, penetrate through the cell membrane, and accumulate in the cell nucleus, which purposefully allows their use in the health sciences as imaging probes and drug carriers in the cancer therapy. The aim of this study was to investigate the effect of low doses of SWCNTs on the expression of microRNAs associated with the cell proliferation and the brain development in zebrafish (Danio rerio) embryos. Methods. The zebrafish embryos (72 h post fertilization) were exposed to low doses of SWCNTs (2 and 8 ng/ml of medium) for 24 or 72 h. The microRNAs (miR-19, miR-21, miR-96, miR-143, miR-145, miR-182, and miR-206) expression levels were measured by quantitative polymerase chain reaction analysis. Results. It was found that low doses of SWCNTs elicited dysregulation in the expression of numerous cell proliferation and brain development-related microRNAs (miR-19, miR-21, miR-96, miR-143, miR-145, miR-182, and miR-206) in dose- (2 and 8 ng/ml of medium) as well as malformations in the zebrafish embryos brain development in a time-dependent (24 and 72 h) manner. Conclusion. Taken together, the present data indicate that the low doses of SWCNTs disturbed the genome functions and reduced the miR-19, miR-21, miR-96, miR-143, miR-145, miR-182, and miR-206 expression levels in dose- and time-dependent manners and interrupted the brain development in the zebrafish embryos indicating for both the genotoxic and the neurotoxic interventions.

Sporadic Alzheimer's Disease- and Neurotoxicity-Related microRNAs Affecting Key Events of Tau-Driven Adverse Outcome Pathway Toward Memory Loss

BACKGROUND

A complex network of aging-related homeostatic pathways that are sensitive to further deterioration in the presence of genetic, systemic, and environmental risk factors, and lifestyle, is implicated in the pathogenesis of progressive neurodegenerative diseases, such as sporadic (late-onset) Alzheimer's disease (sAD).

OBJECTIVE

Since sAD pathology and neurotoxicity share microRNAs (miRs) regulating common as well as overlapping pathological processes, environmental neurotoxic compounds are hypothesized to exert a risk for sAD initiation and progression.

METHODS

Literature search for miRs associated with human sAD and environmental neurotoxic compounds was conducted. Functional miR analysis using PathDip was performed to create miR-target interaction networks.

RESULTS

The identified miRs were successfully linked to the hypothetical starting point and key events of the earlier proposed tau-driven adverse outcome pathway toward memory loss. Functional miR analysis confirmed most of the findings retrieved from literature and revealed some interesting findings. The analysis identified 40 miRs involved in both sAD and neurotoxicity that dysregulated processes governing the plausible adverse outcome pathway for memory loss.

CONCLUSION

Creating miR-target interaction networks related to pathological processes involved in sAD initiation and progression, and environmental chemical-induced neurotoxicity, respectively, provided overlapping miR-target interaction networks. This overlap offered an opportunity to create an alternative picture of the mechanisms underlying sAD initiation and early progression. Looking at initiation and progression of sAD from this new angle may open for new biomarkers and novel drug targets for sAD before the appearance of the first clinical symptoms.

The Biogenesis of miRNAs and Their Role in the Development of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects upper and lower motor neurons. As there is no effective treatment for ALS, it is particularly important to screen key gene therapy targets. The identifications of microRNAs (miRNAs) have completely changed the traditional view of gene regulation. miRNAs are small noncoding single-stranded RNA molecules involved in the regulation of post-transcriptional gene expression. Recent advances also indicate that miRNAs are biomarkers in many diseases, including neurodegenerative diseases. In this review, we summarize recent advances regarding the mechanisms underlying the role of miRNAs in ALS pathogenesis and its application to gene therapy for ALS. The potential of miRNAs to target diverse pathways opens a new avenue for ALS therapy.

Liraglutide Improves Cognitive and Neuronal Function in 3-NP Rat Model of Huntington's Disease

Huntington’s disease (HD) is an autosomal dominant inherited neurodegenerative disease characterized by progressive motor, psychiatric, and cognitive abnormalities. The antidiabetic drug liraglutide possesses a neuroprotective potential against several neurodegenerative disorders; however, its role in Huntington’s disease (HD) and the possible mechanisms/trajectories remain elusive, which is the aim of this work. Liraglutide (200 μg/kg, s.c) was administered to rats intoxicated with 3-nitropropionic acid (3-NP) for 4 weeks post HD model induction. Liraglutide abated the 3-NP-induced neurobehavioral deficits (open field and elevated plus maze tests) and histopathological changes. Liraglutide downregulated the striatal mRNA expression of HSP 27, PBR, and GFAP, while it upregulated that of DARPP32. On the molecular level, liraglutide enhanced striatal miR-130a gene expression and TrKB protein expression and its ligand BDNF, while it reduced the striatal protein content and mRNA expression of the death receptors sortilin and p75NTR, respectively. It enhanced the neuroprotective molecules cAMP, p-PI3K, p-Akt, and p-CREB, besides modulating the p-GSK-3β/p-β-catenin axis. Liraglutide enhanced the antioxidant transcription factor Nrf2, abrogated TBARS, upregulated both Bcl2 and Bcl-XL, and downregulated Bax along with decreasing caspase-3 activity. Therefore, liraglutide exerts a neurotherapeutic effect on 3-NP-treated rats that is, besides the upturn of behavioral and structural findings, it at least partially, increased miR-130a and modulated PI3K/Akt/CREB/BDNF/TrKB, sortilin, and p75NTR, and Akt/GSK-3β/p-β-catenin trajectories besides its capacity to decrease apoptosis and oxidative stress, as well as its neurotrophic activity.

Brain Tumors and Circulating microRNAs: A Systematic Review and Diagnostic Meta-Analysis

PURPOSE

Brain tumors (BT) are among the most prevalent cancers in recent years. Various studies have examined the diagnostic role of microRNAs in different diseases; however, their diagnostic role in BT has not been comprehensively investigated. Therefore, this meta-analysis was performed to assess microRNAs in the blood of patients with BTs accurately.

METHODS

Twenty-six eligible studies were included for analysis. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), area under curve (AUC), Q*index, summary receiver-operating characteristic (SROC) were assessed using the Meta-Disc V.1.4 and Comprehensive Meta-Analysis V.3.3 software. The Egger's test was used to evaluate publication bias in this study.

RESULTS

The diagnostic accuracy of microRNA was high in identifying BT based on the pooled sensitivity 0.82 (95% CI: 0.816 - 0.84), specificity 0.82 (95% CI: 0.817 - 0.84), PLR 5.101 (95% CI: 3.99 - 6.51), NLR 0.187 (95% CI: 0.149 - 0.236), DOR 34.07 (95% CI: 22.56 - 51.43) as well as AUC (0.92), and Q*-index (0.86). Subgroup analyses was also performed for sample types (serum/plasma), reference genes (RNU6, miR-39, and miR-24), and region to determine the diagnostic power of microRNAs in the diagnosis of BT using pooled sensitivity, specificity, PLR, NLR, AUC, and DOR.

CONCLUSION

This meta-analysis proved that circulating microRNAs were the potential markers for BT and could potentially be used as non-invasive early detection biomarkers.

Nutraceutical regulation of miRNAs involved in neurodegenerative diseases and brain cancers

The human brain is a well-connected, intricate network of neurons and supporting glial cells. Neurodegenerative diseases arise as a consequence of extensive loss of neuronal cells leading to disruption of their natural structure and function. On the contrary, rapid proliferation and growth of glial as well as neuronal cells account for the occurrence of malignancy in brain. In both cases, the molecular microenvironment holds pivotal importance in the progression of the disease. MicroRNAs (miRNA) are one of the major components of the molecular microenvironment. miRNAs are small, noncoding RNAs that control gene expression post-transcriptionally. As compared to other tissues, the brain expresses a substantially high number of miRNAs. In the early stage of neurodegeneration, miRNA expression upregulates, while in oncogenesis, miRNA expression is gradually lost. Neurodegeneration and brain cancer is presumed to be under the influence of identical pathways of cell proliferation, differentiation and cell death which are tightly regulated by miRNAs. It has been confirmed experimentally that miRNA expression can be regulated by nutraceuticals - macronutrients, micronutrients or natural products derived from food; thereby making dietary supplements immensely significant for targeting miRNAs having altered expression patterns during neurodegeneration or oncogenesis. In this review, we will discuss in detail, about the common miRNAs involved in brain cancers and neurodegenerative diseases along with the comprehensive list of miRNAs involved separately in both pathological conditions. We will also discuss the role of nutraceuticals in the regulation of those miRNAs which are involved in both of these pathological conditions.

Alzheimer's Disease and microRNA-132: A Widespread Pathological Factor and Potential Therapeutic Target

Alzheimer's disease (AD) is a common neurodegenerative disease in the elderly and is the most common type of dementia. AD is mostly gradual onset, and involves slow, progressive mental decline, accompanied by personality changes; the incidence of AD gradually increases with age. The etiology of AD is unknown, although it is currently believed to be related to abnormal deposition of amyloid β-protein (Aβ) in the brain, hyperphosphorylation of microtubule-associated protein tau, and the release of various cytokines, complements, activators and chemokines by cells. MicroRNAs (miRNAs) are a class of highly conserved non-coding RNAs that regulate gene expression at the post-transcriptional level, and manipulate the functions of intracellular proteins and physiological processes. Emerging studies have shown that miRNA plays an important role in regulating AD-related genes. MiR-132 is known as "NeurimmiR" due to its involvement in numerous neurophysiological and pathological processes. Accumulating pre-clinical results suggest that miR-132 may be involved in the progression of Aβ and tau pathology. Moreover, clinical studies have indicated that decreased circulating miR-132 levels could be used a potential diagnostic biomarker in AD. Here, we review the pathogenic role of miR-132 activity in AD, and the potential of targeting miR-132 for developing future therapeutic strategies.

miRNAs as biomarkers for early cancer detection and their application in the development of new diagnostic tools

Over the last decades, microRNAs (miRNAs) have emerged as important molecules associated with the regulation of gene expression in humans and other organisms, expanding the strategies available to diagnose and handle several diseases. This paper presents a systematic review of literature of miRNAs related to cancer development and explores the main techniques used to quantify these molecules and their limitations as screening strategy. The bibliographic research was conducted using the online databases, PubMed, Google Scholar, Web of Science, and Science Direct searching the terms "microRNA detection", "miRNA detection", "miRNA and prostate cancer", "miRNA and cervical cancer", "miRNA and cervix cancer", "miRNA and breast cancer", and "miRNA and early cancer diagnosis". Along the systematic review over 26,000 published papers were reported, and 252 papers were returned after applying the inclusion and exclusion criteria, which were considered during this review. The aim of this study is to identify potential miRNAs related to cancer development that may be useful for early cancer diagnosis, notably in the breast, prostate, and cervical cancers. In addition, we suggest a preliminary top 20 miRNA panel according to their relevance during the respective cancer development. Considering the progressive number of new cancer cases every year worldwide, the development of new diagnostic tools is critical to refine the accuracy of screening tests, improving the life expectancy and allowing a better prognosis for the affected patients.

miR-24 targets SARS-CoV-2 co-factor Neuropilin-1 in human brain microvascular endothelial cells: Insights for COVID-19 neurological manifestations

Neuropilin-1 is a transmembrane glycoprotein that has been implicated in several processes including angiogenesis and immunity. Recent evidence has also shown that it is implied in the cellular internalization of the severe acute respiratory syndrome coronavirus (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19). We hypothesized that specific microRNAs can target Neuropilin-1. By combining bioinformatic and functional approaches, we identified miR-24 as a regulator of Neuropilin-1 transcription. Since Neuropilin-1 has been shown to play a key role in the endothelium-mediated regulation of the blood-brain barrier, we validated miR-24 as a functional modulator of Neuropilin-1 in human brain microvascular endothelial cells (hBMECs), which are the most suitable cell line for an in vitro bloodâ€"brain barrier model.

miR-24 Targets the Transmembrane Glycoprotein Neuropilin-1 in Human Brain Microvascular Endothelial Cells

Neuropilin-1 is a transmembrane glycoprotein that has been implicated in several processes including angiogenesis and immunity. Recent evidence has also shown that it is implied in the cellular internalization of the severe acute respiratory syndrome coronavirus (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19). We hypothesized that specific microRNAs can target Neuropilin-1. By combining bioinformatic and functional approaches, we identified miR-24 as a regulator of Neuropilin-1 transcription. Since Neuropilin-1 has been shown to play a key role in the endothelium-mediated regulation of the blood-brain barrier, we validated miR-24 as a functional modulator of Neuropilin-1 in human brain microvascular endothelial cells (hBMECs), which are the most suitable cell line for an in vitro blood-brain barrier model.

Targeting MicroRNA-125b Promotes Neurite Outgrowth but Represses Cell Apoptosis and Inflammation via Blocking PTGS2 and CDK5 in a FOXQ1-Dependent Way in Alzheimer Disease

This study aimed to explore the molecular regulatory network among microRNA-125b (miR-125b), forkhead box Q1 (FOXQ1), prostaglandin-endoperoxide synthase 2 (PTGS2), and cyclin-dependent kinase 5 (CDK5), as well as their effects on cell apoptosis, neurite outgrowth, and inflammation in Alzheimer disease (AD). Rat embryo cerebral cortex neurons and nerve growth factor-stimulated PC12 cells were insulted by Aβ_1-42 to construct two AD cellular models. Negative control (NC) inhibitor, miR-125b inhibitor, NC siRNA, FOXQ1 siRNA, PTGS2 siRNA, and CDK5 siRNA were transferred into the two AD cellular models alone or combined. Then, cell apoptosis, neurite outgrowth, proinflammatory cytokines, miR-125b, FOXQ1, PTGS2, and CDK5 expressions were detected. MiR-125b inhibition facilitated neurite outgrowth but suppressed cell apoptosis and proinflammatory cytokines (tumor necrosis factor-α, interleukin 1β, and interleukin 6); meanwhile, it upregulated FOXQ1 but downregulated PTGS2 and CDK5. Furthermore, FOXQ1 inhibition promoted cell apoptosis and proinflammatory cytokines but repressed neurite outgrowth; PTGS2 inhibition achieved the opposite effects; CDK5 inhibition attenuated cell apoptosis, whereas it less affected neurite outgrowth and inflammation. Notably, FOXQ1 inhibition attenuated, whereas PTGS2 inhibition elevated the effect of miR-125b inhibition on regulating neurite outgrowth, cell apoptosis, and proinflammatory cytokines. As for CDK5 inhibition, it enhanced the effect of miR-125b inhibition on regulating cell apoptosis, but less impacted the neurite outgrowth and proinflammatory cytokines. Additionally, PTGS2 inhibition and CDK5 inhibition both reversed the effect of FOXQ1 inhibition on regulating cell apoptosis, neurite outgrowth, and proinflammatory cytokines. In conclusion, targeting miR-125b alleviates AD progression via blocking PTGS2 and CDK5 in a FOXQ1-dependent way.

The underlying molecular mechanism and drugs for treatment in adrenal cortical carcinoma

Purpose: The study aimed to predict and explore the possible clinical value and mechanism of genetic markers in adrenal cortical carcinoma using a bioinformatics analysis method. Methods: The RNA-seqs and miRNAs data were downloaded from TCGA database to identify the differentially expressed genes and differentially expressed miRNAs. The hub-genes were screened by building protein-protein interaction sub-networks with 12 topological analysis methods. We conducted the receiver operating characteristic curve to elevate the diagnostic value of hub-genes in distinguishing the death and alive groups. The survival analysis of hub-genes and key miRNAs were conducted using Kaplan-Meier curves. Furthermore, most significant small molecules were identified as therapeutic candidates for adrenal cortical carcinoma by the CMap analysis. Results: Compared to survival group, we found 475 up-regulated genes and 354 genes and the key pathways leading to the death of different ACC individual patients. Then we used 12 topological analysis methods to found the most possible 22 hub-genes. Among these hub-genes, nine hub-genes (C3, CXCL5, CX3CR1, GRM8, HCAR2, HTR1B, SUCNR1, PTGER3 and SSTR1) could be used to distinguish the death and survival groups for patients. We also revealed that mRNA expressions of 12 genes (C3, CXCL8, CX3CR1, GNAT3, GNGT1, GRM8, HCAR2, HTR1B, HTR1D, PTGER3, SSTR1 and SUCNR1) and four key miRNAs (hsa-mir-330, hsa-mir-489, hsa-mir-508 and hsa-mir-513b) were related to survival. Three most small molecules were identified (H-9, AZ-628 and phensuximide) as potential therapeutic drugs for adrenal cortical carcinoma. Conclusion: The hub-genes expression was significant useful in adrenal cortical carcinoma, provide new diagnostic, prognosis and therapeutic approaches for adrenal cortical carcinoma. Furthermore, we also explore the possible miRNAs involved in regulation of hub-genes.

Potential role of exosome in post-stroke reorganization and/or neurodegeneration

Currently, stroke is a common and devastating condition, which is sometimes associated with permanent cerebral damages. Although in early time after stroke, the related treatments are mainly focused on the restoration of cerebral blood flow (CBF), at the same time, some changes are commencing that continue for a long time and need to be specially noticed. Previous studies have proposed several molecular mechanisms in these post-stroke events. Exosomes are a type of vesicle, which are formed and secreted by most cells as a mean to transfer cellular constituents such as proteins, DNA and/or RNA to distant cells. Therefore, they are considered as a novel mechanism of cellular communication. Herein, we reviewed the current knowledge on cascades, which are activated after stroke and consequently lead to the reorganization and/or continuance of tissue damage and development of other disorders such as Neurodegenerative diseases (ND). Thereafter, we summarized the latest proofs about the possible participation of exosomes in transferring some components such as proteins and micro-RNAs (miRs), from the affected areas to other parts of the brain and eventually cause the above-mentioned post-stroke events.

Exosomes and exosomal microRNA in non-targeted radiation bystander and abscopal effects in the central nervous system

Localized cranial radiotherapy is a dominant treatment for brain cancers. After being subjected to radiation, the central nervous system (CNS) exhibits targeted effects as well as non-targeted radiation bystander effects (RIBE) and abscopal effects (RIAE). Radiation-induced targeted effects in the CNS include autophagy and various changes in tumor cells due to radiation sensitivity, which can be regulated by microRNAs. Non-targeted radiation effects are mainly induced by gap junctional communication between cells, exosomes containing microRNAs can be transduced by intracellular endocytosis to regulate RIBE and RIAE. In this review, we discuss the involvement of microRNAs in radiation-induced targeted effects, as well as exosomes and/or exosomal microRNAs in non-targeted radiation effects in the CNS. As a target pathway, we also discuss the Akt pathway which is regulated by microRNAs, exosomes, and/or exosomal microRNAs in radiation-induced targeted effects and RIBE in CNS tumor cells. As the CNS-derived exosomes can cross the blood-brain-barrier (BBB) into the bloodstream and be isolated from peripheral blood, exosomes and exosomal microRNAs can emerge as promising minimally invasive biomarkers and therapeutic targets for radiation-induced targeted and non-targeted effects in the CNS.

Hsa-miR-27a-3p and epidermal growth factor receptor expression analysis in glioblastoma FFPE samples

AIM

Glioblastoma multiforme (GBM) is the most invasive type of glial tumors. MicroRNAs as the small, noncoding RNAs have been revealed that play an important role in tumorigenic processes. So, they may be used as potential biomarkers for detection and prognosis of cancers at the early stages. In addition, they can be applied as therapeutic targets. In the present study, the expression levels of hsa-miR-27a-3p and EGFR were investigated in GBM.

METHODS

Real-time RT-PCR was applied to evaluate hsa-miR-27a-3p and EGFR expressions in the formalin-fixed paraffin-embedded (FFPE) tissue samples obtained from 50 GBM and 50 normal people.

RESULTS

The expression level of hsa-miR-27a-3p and EGFR was significantly different between cases and controls. Positive association was found between gene expressions and immunohistochemistry markers, such as Ki67 and glial fibrillary acidic protein, except for IDH1 status.

CONCLUSION

We showed the association of hsa-miR-27a-3p and EGFR with GBM and it can be concluded that they have a promising potential to use as primary cancer biomarkers.

Biomolecules and Electrochemical Tools in Chronic Non-Communicable Disease Surveillance: A Systematic Review

Over recent three decades, the electrochemical techniques have become widely used in biological identification and detection, because it presents optimum features for efficient and sensitive molecular detection of organic compounds, being able to trace quantities with a minimum of reagents and sample manipulation. Given these special features, electrochemical techniques are regularly exploited in disease diagnosis and monitoring. Specifically, amperometric electrochemical analysis has proven to be quite suitable for the detection of physiological biomarkers in monitoring health conditions, as well as toward the control of reactive oxygen species released in the course of oxidative burst during inflammatory events. Besides, electrochemical detection techniques involve a simple and swift assessment that provides a low detection-limit for most of the molecules enclosed biological fluids and related to non-transmittable morbidities.

Therapeutically Significant MicroRNAs in Primary and Metastatic Brain Malignancies

Simple Summary

The overall survival of brain cancer patients remains grim, with conventional therapies such as chemotherapy and radiotherapy only providing marginal benefits to patient survival. Cancers are complex, with multiple pathways being dysregulated simultaneously. Non-coding RNAs such as microRNA (miRNAs) are gaining importance due to their potential in regulating a variety of targets implicated in the pathology of cancers. This could be leveraged for the development of targeted and personalized therapies for cancers. Since miRNAs can upregulate and/or downregulate proteins, this review aims to understand the role of these miRNAs in primary and metastatic brain cancers. Here, we discuss the regulatory mechanisms of ten miRNAs that are highly dysregulated in glioblastoma and metastatic brain tumors. This will enable researchers to develop miRNA-based targeted cancer therapies and identify potential prognostic biomarkers.

Abstract

Brain cancer is one among the rare cancers with high mortality rate that affects both children and adults. The most aggressive form of primary brain tumor is glioblastoma. Secondary brain tumors most commonly metastasize from primary cancers of lung, breast, or melanoma. The five-year survival of primary and secondary brain tumors is 34% and 2.4%, respectively. Owing to poor prognosis, tumor heterogeneity, increased tumor relapse, and resistance to therapies, brain cancers have high mortality and poor survival rates compared to other cancers. Early diagnosis, effective targeted treatments, and improved prognosis have the potential to increase the survival rate of patients with primary and secondary brain malignancies. MicroRNAs (miRNAs) are short noncoding RNAs of approximately 18–22 nucleotides that play a significant role in the regulation of multiple genes. With growing interest in the development of miRNA-based therapeutics, it is crucial to understand the differential role of these miRNAs in the given cancer scenario. This review focuses on the differential expression of ten miRNAs (miR-145, miR-31, miR-451, miR-19a, miR-143, miR-125b, miR-328, miR-210, miR-146a, and miR-126) in glioblastoma and brain metastasis. These miRNAs are highly dysregulated in both primary and metastatic brain tumors, which necessitates a better understanding of their role in these cancers. In the context of the tumor microenvironment and the expression of different genes, these miRNAs possess both oncogenic and/or tumor-suppressive roles within the same cancer.

Neuroprotective effect of 3,3'-Diindolylmethane against perinatal asphyxia involves inhibition of the AhR and NMDA signaling and hypermethylation of specific genes

Each year, 1 million children die due to perinatal asphyxia; however, there are no effective drugs to protect the neonatal brain against hypoxic/ischemic damage. In this study, we demonstrated for the first time the neuroprotective capacity of 3,3’-diindolylmethane (DIM) in an in vivo model of rat perinatal asphyxia, which has translational value and corresponds to hypoxic/ischemic episodes in human newborns. Posttreatment with DIM restored the weight of the ipsilateral hemisphere and normalized cell number in the brain structures of rats exposed to perinatal asphyxia. DIM also downregulated the mRNA expression of HIF1A-regulated Bnip3 and Hif1a which is a hypoxic marker, and the expression of miR-181b which is an indicator of perinatal asphyxia. In addition, DIM inhibited apoptosis and oxidative stress accompanying perinatal asphyxia through: downregulation of FAS, CASP-3, CAPN1, GPx3 and SOD-1, attenuation of caspase-9 activity, and upregulation of anti-apoptotic Bcl2 mRNA. The protective effects of DIM were accompanied by the inhibition of the AhR and NMDA signaling pathways, as indicated by the reduced expression levels of AhR, ARNT, CYP1A1, GluN1 and GluN2B, which was correlated with enhanced global DNA methylation and the methylation of the Ahr and Grin2b genes. Because our study provided evidence that in rat brain undergoing perinatal asphyxia, DIM predominantly targets AhR and NMDA, we postulate that compounds that possess the ability to inhibit their signaling are promising therapeutic tools to prevent stroke.

Oxidative Stress-Part of the Solution or Part of the Problem in the Hypoxic Environment of a Brain Tumor

Rapid growth of brain tumors such as glioblastoma often results in oxygen deprivation and the emergence of hypoxic zones. In consequence, the enrichment of reactive oxygen species occurs, harming nonmalignant cells and leading them toward apoptotic cell death. However, cancer cells survive such exposure and thrive in a hypoxic environment. As the mechanisms responsible for such starkly different outcomes are not sufficiently explained, we aimed to explore what transcriptome rearrangements are used by glioblastoma cells in hypoxic areas. Using metadata analysis of transcriptome in different subregions of the glioblastoma retrieved from the Ivy Glioblastoma Atlas Project, we created the reactive oxygen species-dependent map of the transcriptome. This map was then used for the analysis of differential gene expression in the histologically determined cellular tumors and hypoxic zones. The gene ontology analysis cross-referenced with the clinical data from The Cancer Genome Atlas revealed that the metabolic shift is one of the major prosurvival strategies applied by cancer cells to overcome hypoxia-related cytotoxicity.

Hypoxic Roadmap of Glioblastoma-Learning about Directions and Distances in the Brain Tumor Environment

Malignant brain tumor-glioblastoma is not only difficult to treat but also hard to study and model. One of the reasons for these is their heterogeneity, i.e., individual tumors consisting of cancer cells that are unlike each other. Such diverse cells can thrive due to the simultaneous co-evolution of anatomic niches and adaption into zones with distorted homeostasis of oxygen. It dampens cytotoxic and immune therapies as the response depends on the cellular composition and its adaptation to hypoxia. We explored what transcriptome reposition strategies are used by cells in the different areas of the tumor. We created the hypoxic map by differential expression analysis between hypoxic and cellular features using RNA sequencing data cross-referenced with the tumor's anatomic features (Ivy Glioblastoma Atlas Project). The molecular functions of genes differentially expressed in the hypoxic regions were analyzed by a systematic review of the gene ontology analysis. To put a hypoxic niche signature into a clinical context, we associated the model with patients' survival datasets (The Cancer Genome Atlas). The most unique class of genes in the hypoxic area of the tumor was associated with the process of autophagy. Both hypoxic and cellular anatomic features were enriched in immune response genes whose, along with autophagy cluster genes, had the power to predict glioblastoma patient survival. Our analysis revealed that transcriptome responsive to hypoxia predicted worse patients' outcomes by driving tumor cell adaptation to metabolic stress and immune escape.

Neuro-toxic and Reproductive Effects of BPA

Background:

Bisphenol A (BPA) is one of the highest volume chemicals produced worldwide. It has recognized activity as an endocrine-disrupting chemical and has suspected roles as a neurological and reproductive toxicant. It interferes in steroid signaling, induces oxidative stress, and affects gene expression epigenetically. Gestational, perinatal and neonatal exposures to BPA affect developmental processes, including brain development and gametogenesis, with consequences on brain functions, behavior, and fertility.

Methods:

This review critically analyzes recent findings on the neuro-toxic and reproductive effects of BPA (and its ana-logues), with focus on neuronal differentiation, synaptic plasticity, glia and microglia activity, cognitive functions, and the central and local control of reproduction.

Results:

BPA has potential human health hazard associated with gestational, peri- and neonatal exposure. Beginning with BPA’s disposition, this review summarizes recent findings on the neurotoxicity of BPA and its analogues, on neuronal dif-ferentiation, synaptic plasticity, neuro-inflammation, neuro-degeneration, and impairment of cognitive abilities. Furthermore, it reports the recent findings on the activity of BPA along the HPG axis, effects on the hypothalamic Gonadotropin Releas-ing Hormone (GnRH), and the associated effects on reproduction in both sexes and successful pregnancy.

Conclusion:

BPA and its analogues impair neuronal activity, HPG axis function, reproduction, and fertility. Contrasting re-sults have emerged in animal models and human. Thus, further studies are needed to better define their safety levels. This re-view offers new insights on these issues with the aim to find the “fil rouge”, if any, that characterize BPA’s mechanism of action with outcomes on neuronal function and reproduction.

Identification of differentially expressed microRNAs and their target genes in the hippocampal tissues of Fmr1 knockout mice

Fragile X syndrome (FXS) is one of the most common forms of inherited mental retardation; it is usually associated with the transcriptional silencing of the Fmr1 gene and loss of its encoded protein, the fragile X mental retardation protein (FMRP). FMRP is an RNA-binding protein and participates in regulating the development of dendritic spines and synaptic plasticity. To uncover the possible role of microRNAs (miRNAs) in FXS and their relationship with FMRP, we used microarray analysis to investigate the miRNA expression profiles in the hippocampal tissues of Fmr1 knockout (Fmr1-KO) mice and wild type (WT) mice. A total of 75 differentially expressed miRNAs were identified, of which 58 were significantly upregulated and no miRNAs were significantly downregulated in Fmr1-KO mice. Quantitative real-time PCR (qRT-PCR) analysis was applied to validate the expression of 7 upregulated miRNAs; results indicated that the levels of only miR-449a and miR-720 were significantly upregulated. We further used bioinformatics software and databases to predict the target genes of these two miRNAs. The genes were related to dendritic spine development and synaptic plasticity; the qRT-PCR and western blotting results showed that cyclin-dependent kinase 5 (CDK5) and synaptotagmin 1 (SYT1) were differentially expressed in the Fmr1-KO mice and WT mice. In conclusion, this study evidenced diverse changes in the expression of miRNAs, and validated the miRNAs and their targeted genes in Fmr1-KO mice. Although further studies are required to better understand the function of miRNAs in FXS, the present research highlights a potential role of miRNAs in the pathogenesis of FXS.

Circulating RNAs as Potential Biomarkers in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a complex multi-system neurodegenerative disorder with currently limited diagnostic and no therapeutic options. Despite the intense efforts no clinically applicable biomarkers for ALS are yet established. Most current research is thus focused, in particular, in identifying potential non-invasive circulating biomarkers for more rapid and accurate diagnosis and monitoring of the disease. In this review, we have focused on messenger RNA (mRNA), non-coding RNAs (lncRNAs), micro RNAs (miRNAs) and circular RNA (circRNAs) as potential biomarkers for ALS in peripheral blood serum, plasma and cells. The most promising miRNAs include miR-206, miR-133b, miR-27a, mi-338-3p, miR-183, miR-451, let-7 and miR-125b. To test clinical potential of this miRNA panel, a useful approach may be to perform such analysis on larger multi-center scale using similar experimental design. However, other types of RNAs (lncRNAs, circRNAs and mRNAs) that, together with miRNAs, represent RNA networks, have not been yet extensively studied in blood samples of patients with ALS. Additional research has to be done in order to find robust circulating biomarkers and therapeutic targets that will distinguish key RNA interactions in specific ALS-types to facilitate diagnosis, predict progression and design therapy.

A Network-Based Bioinformatics Approach to Identify Molecular Biomarkers for Type 2 Diabetes that Are Linked to the Progression of Neurological Diseases

Neurological diseases (NDs) are progressive disorders, the progression of which can be significantly affected by a range of common diseases that present as comorbidities. Clinical studies, including epidemiological and neuropathological analyses, indicate that patients with type 2 diabetes (T2D) have worse progression of NDs, suggesting pathogenic links between NDs and T2D. However, finding causal or predisposing factors that link T2D and NDs remains challenging. To address these problems, we developed a high-throughput network-based quantitative pipeline using agnostic approaches to identify genes expressed abnormally in both T2D and NDs, to identify some of the shared molecular pathways that may underpin T2D and ND interaction. We employed gene expression transcriptomic datasets from control and disease-affected individuals and identified differentially expressed genes (DEGs) in tissues of patients with T2D and ND when compared to unaffected control individuals. One hundred and ninety seven DEGs (99 up-regulated and 98 down-regulated in affected individuals) that were common to both the T2D and the ND datasets were identified. Functional annotation of these identified DEGs revealed the involvement of significant cell signaling associated molecular pathways. The overlapping DEGs (i.e., seen in both T2D and ND datasets) were then used to extract the most significant GO terms. We performed validation of these results with gold benchmark databases and literature searching, which identified which genes and pathways had been previously linked to NDs or T2D and which are novel. Hub proteins in the pathways were identified (including DNM2, DNM1, MYH14, PACSIN2, TFRC, PDE4D, ENTPD1, PLK4, CDC20B, and CDC14A) using protein-protein interaction analysis which have not previously been described as playing a role in these diseases. To reveal the transcriptional and post-transcriptional regulators of the DEGs we used transcription factor (TF) interactions analysis and DEG-microRNAs (miRNAs) interaction analysis, respectively. We thus identified the following TFs as important in driving expression of our T2D/ND common genes: FOXC1, GATA2, FOXL1, YY1, E2F1, NFIC, NFYA, USF2, HINFP, MEF2A, SRF, NFKB1, USF2, HINFP, MEF2A, SRF, NFKB1, PDE4D, CREB1, SP1, HOXA5, SREBF1, TFAP2A, STAT3, POU2F2, TP53, PPARG, and JUN. MicroRNAs that affect expression of these genes include mir-335-5p, mir-16-5p, mir-93-5p, mir-17-5p, mir-124-3p. Thus, our transcriptomic data analysis identifies novel potential links between NDs and T2D pathologies that may underlie comorbidity interactions, links that may include potential targets for therapeutic intervention. In sum, our neighborhood-based benchmarking and multilayer network topology methods identified novel putative biomarkers that indicate how type 2 diabetes (T2D) and these neurological diseases interact and pathways that, in the future, may be targeted for treatment.

Candidate Genes and MiRNAs Linked to the Inverse Relationship Between Cancer and Alzheimer's Disease: Insights From Data Mining and Enrichment Analysis

The incidence of cancer and Alzheimer’s disease (AD) increases exponentially with age. A growing body of epidemiological evidence and molecular investigations inspired the hypothesis of an inverse relationship between these two pathologies. It has been proposed that the two diseases might utilize the same proteins and pathways that are, however, modulated differently and sometimes in opposite directions. Investigation of the common processes underlying these diseases may enhance the understanding of their pathogenesis and may also guide novel therapeutic strategies. Starting from a text-mining approach, our in silico study integrated the dispersed biological evidence by combining data mining, gene set enrichment, and protein-protein interaction (PPI) analyses while searching for common biological hallmarks linked to AD and cancer. We retrieved 138 genes (ALZCAN gene set), computed a significant number of enriched gene ontology clusters, and identified four PPI modules. The investigation confirmed the relevance of autophagy, ubiquitin proteasome system, and cell death as common biological hallmarks shared by cancer and AD. Then, from a closer investigation of the PPI modules and of the miRNAs enrichment data, several genes (SQSTM1, UCHL1, STUB1, BECN1, CDKN2A, TP53, EGFR, GSK3B, and HSPA9) and miRNAs (miR-146a-5p, MiR-34a-5p, miR-21-5p, miR-9-5p, and miR-16-5p) emerged as promising candidates. The integrative approach uncovered novel miRNA-gene networks (e.g., miR-146 and miR-34 regulating p62 and Beclin1 in autophagy) that might give new insights into the complex regulatory mechanisms of gene expression in AD and cancer.

MicroRNA Signature in Human Normal and Tumoral Neural Stem Cells

MicroRNAs, also called miRNAs or simply miR-, represent a unique class of non-coding RNAs that have gained exponential interest during recent years because of their determinant involvement in regulating the expression of several genes. Despite the increasing number of mature miRNAs recognized in the human species, only a limited proportion is engaged in the ontogeny of the central nervous system (CNS). miRNAs also play a pivotal role during the transition of normal neural stem cells (NSCs) into tumor-forming NSCs. More specifically, extensive studies have identified some shared miRNAs between NSCs and neural cancer stem cells (CSCs), namely miR-7, -124, -125, -181 and miR-9, -10, -130. In the context of NSCs, miRNAs are intercalated from embryonic stages throughout the differentiation pathway in order to achieve mature neuronal lineages. Within CSCs, under a different cellular context, miRNAs perform tumor suppressive or oncogenic functions that govern the homeostasis of brain tumors. This review will draw attention to the most characterizing studies dealing with miRNAs engaged in neurogenesis and in the tumoral neural stem cell context, offering the reader insight into the power of next generation miRNA-targeted therapies against brain malignances.

The analysis of miRNA expression profiling datasets reveals inverse microRNA patterns in glioblastoma and Alzheimer's disease

There is recent evidence to indicate the existence of an inverse association between the incidence of neurological disorders and cancer development. Concurrently, the transcriptional pathways responsible for the onset of glioblastoma multiforme (GBM) and Alzheimer's disease (AD) have been found to be mutually exclusive between the two pathologies. Despite advancements being made concerning the knowledge of the molecular mechanisms responsible for the development of GBM and AD, little is known about the identity of the microRNA (miRNAs or miRs) involved in the development and progression of these two pathologies and their possible inverse expression patterns. On these bases, the aim of the present study was to identify a set of miRNAs significantly de-regulated in both GBM and AD, and hence to determine whether the identified miRNAs exhibit an inverse association within the two pathologies. For this purpose, miRNA expression profiling datasets derived from the Gene Expression Omnibus (GEO) DataSets and relative to GBM and AD were used. Once the miRNAs significantly de-regulated in both pathologies were identified, DIANA-mirPath pathway prediction and STRING Gene Ontology enrichment analyses were performed to establish their functional roles in each of the pathologies. The results allowed the identification of a set of miRNAs found de-regulated in both GBM and AD, whose expression levels were inversely associated in the two pathologies. In particular, a strong negative association was observed between the expression levels of miRNAs in GBM compared to AD, suggesting that although the molecular pathways behind the development of these two pathologies are the same, they appear to be inversely regulated by miRNAs. Despite the identification of this set of miRNAs which may be used for diagnostic, prognostic and therapeutic purposes, further functional in vitro and in vivo evaluations are warranted in order to validate the diagnostic and therapeutic potential of the identified miRNAs, as well as their involvement in the development of GBM and AD.