Causes and Consequences of MicroRNA Dysregulation in Neurodegenerative Diseases

Modeling ncRNA-Mediated Circuits in Cell Fate Decision: From Systems Biology to Synthetic Biology

Noncoding RNAs (ncRNAs) play critical roles in essential cell fate decisions. However, the exact molecular mechanisms underlying ncRNA-mediated bistable switches remain elusive and controversial. In recent years, systematic mathematical and quantitative experimental analyses have made significant contributions to elucidating the molecular mechanisms of controlling ncRNA-mediated cell fate decision processes. In this chapter, we review and summarize the general framework of mathematical modeling of ncRNA in a pedagogical way and the application of this general framework to real biological processes. We discuss the emerging properties resulting from the reciprocal regulation between mRNA, miRNA, and competing endogenous mRNA (ceRNA). We also explore the efforts within the synthetic biology approach to understand the fundamental design principles underlying cell fate decisions. Both the positive feedback loops between ncRNAs and transcription factors and the emerging properties from the miRNA-mRNA reciprocal regulation enable bistable switches to direct cell fate decisions.

MicroRNAs regulation in Parkinson's disease, and their potential role as diagnostic and therapeutic targets

MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression by binding to target messenger RNA (mRNA) molecules and promoting their degradation or blocking their translation. Parkinson's disease (PD) is a neurodegenerative disorder caused by the loss of dopaminergic neurons in the substantia nigra. There is increasing evidence to suggest that miRNAs play a role in the pathogenesis of PD. Studies have identified several miRNAs that are dysregulated in the brains of PD patients, and animal models of the disease. MiRNA expression dysregulation contributes to the onset and progression of PD by modulating neuroinflammation, oxidative stress, and protein aggregation genes. Moreover, miRNAs have emerged as potential therapeutic targets for PD. This review elucidates the changes in miRNA expression profiles associated with PD, emphasising their potential as diagnostic biomarkers and therapeutic targets, and detailing specific miRNAs implicated in PD and their downstream targets. Integrated Insights into miRNA Function, Microglial Activation, Diagnostic, and Treatment Prospects in PD Note: This figure is an original figure created by the authors.

Neuroinflammation and the role of epigenetic-based therapies for Huntington's disease management: the new paradigm

Huntington's disease (HD) is an inherited, autosomal, neurodegenerative ailment that affects the striatum of the brain. Despite its debilitating effect on its patients, there is no proven cure for HD management as of yet. Neuroinflammation, excitotoxicity, and environmental factors have been reported to influence the regulation of gene expression by modifying epigenetic mechanisms. Aside focusing on the etiology, changes in epigenetic mechanisms have become a crucial factor influencing the interaction between HTT protein and epigenetically transcribed genes involved in neuroinflammation and HD. This review presents relevant literature on epigenetics with special emphasis on neuroinflammation and HD. It summarizes pertinent research on the role of neuroinflammation and post-translational modifications of chromatin, including DNA methylation, histone modification, and miRNAs. To achieve this about 1500 articles were reviewed via databases like PubMed, ScienceDirect, Google Scholar, and Web of Science. They were reduced to 534 using MeSH words like 'epigenetics, neuroinflammation, and HD' coupled with Boolean operators. Results indicated that major contributing factors to the development of HD such as mitochondrial dysfunction, excitotoxicity, neuroinflammation, and apoptosis are affected by epigenetic alterations. However, the association between neuroinflammation-altered epigenetics and the reported transcriptional changes in HD is unknown. Also, the link between epigenetically dysregulated genomic regions and specific DNA sequences suggests the likelihood that transcription factors, chromatin-remodeling proteins, and enzymes that affect gene expression are all disrupted simultaneously. Hence, therapies that target pathogenic pathways in HD, including neuroinflammation, transcriptional dysregulation, triplet instability, vesicle trafficking dysfunction, and protein degradation, need to be developed.

MicroRNA biomarkers as next-generation diagnostic tools for neurodegenerative diseases: a comprehensive review

Neurodegenerative diseases (NDs) are characterized by abnormalities within neurons of the brain or spinal cord that gradually lose function, eventually leading to cell death. Upon examination of affected tissue, pathological changes reveal a loss of synapses, misfolded proteins, and activation of immune cells-all indicative of disease progression-before severe clinical symptoms become apparent. Early detection of NDs is crucial for potentially administering targeted medications that may delay disease advancement. Given their complex pathophysiological features and diverse clinical symptoms, there is a pressing need for sensitive and effective diagnostic methods for NDs. Biomarkers such as microRNAs (miRNAs) have been identified as potential tools for detecting these diseases. We explore the pivotal role of miRNAs in the context of NDs, focusing on Alzheimer's disease, Parkinson's disease, Multiple sclerosis, Huntington's disease, and Amyotrophic Lateral Sclerosis. The review delves into the intricate relationship between aging and NDs, highlighting structural and functional alterations in the aging brain and their implications for disease development. It elucidates how miRNAs and RNA-binding proteins are implicated in the pathogenesis of NDs and underscores the importance of investigating their expression and function in aging. Significantly, miRNAs exert substantial influence on post-translational modifications (PTMs), impacting not just the nervous system but a wide array of tissues and cell types as well. Specific miRNAs have been found to target proteins involved in ubiquitination or de-ubiquitination processes, which play a significant role in regulating protein function and stability. We discuss the link between miRNA, PTM, and NDs. Additionally, the review discusses the significance of miRNAs as biomarkers for early disease detection, offering insights into diagnostic strategies.

Brain-Periphery Interactions in Huntington's Disease: Mediators and Lifestyle Interventions

Prominent pathological features of Huntington's disease (HD) are aggregations of mutated Huntingtin protein (mHtt) in the brain and neurodegeneration, which causes characteristic motor (such as chorea and dystonia) and non-motor symptoms. However, the numerous systemic and peripheral deficits in HD have gained increasing attention recently, since those factors likely modulate disease progression, including brain pathology. While whole-body metabolic abnormalities and organ-specific pathologies in HD have been relatively well described, the potential mediators of compromised inter-organ communication in HD have been insufficiently characterized. Therefore, we applied an exploratory literature search to identify such mediators. Unsurprisingly, dysregulation of inflammatory factors, circulating mHtt, and many other messenger molecules (hormones, lipids, RNAs) were found that suggest impaired inter-organ communication, including of the gut-brain and muscle-brain axis. Based on these findings, we aimed to assess the risks and potentials of lifestyle interventions that are thought to improve communication across these axes: dietary strategies and exercise. We conclude that appropriate lifestyle interventions have great potential to reduce symptoms and potentially modify disease progression (possibly via improving inter-organ signaling) in HD. However, impaired systemic metabolism and peripheral symptoms warrant particular care in the design of dietary and exercise programs for people with HD.

miR-34a/TAN1/CREB Axis Engages in Alleviating Oligodendrocyte Trophic Factor-Induced Myelin Repair Function and Astrocyte-Dependent Neuroinflammation in the Early Stages of Alzheimer's Disease: The Anti-Neurodegenerative Effect of Treadmill Exercise

Reduced myelin stability observed in the early stages of Alzheimer's disease leads to spatial learning and memory impairment. Exercise has been shown to protect nerves, reduce the risk of Alzheimer's disease, and strengthen synaptic connectivity. However, the underlying mechanisms of how exercise can promote myelin repair and coordinate inflammation and proliferation are still uncertain. In this study, we conducted histological and biochemical assays of cortical lysates after behavioral testing to detect pathological changes, myelin sheath thickness, and mRNA and protein levels. It is notable that D-galactose model mice exhibited elevated miRNA-34a levels, overactive astrocytes, decreased myelin staining scores, increased apoptosis, and decreased synaptic plasticity in the brain. Significantly, after eight weeks of exercise, we observed improvements in LFB scores, NeuN( +) neuron counts, and myelin basic protein (MBP) expression. Additionally, exercise promoted the expression of oligodendrocyte markers Olig2 and PDFGR-α associated with brain proliferation, and improved spatial cognitive function. Furthermore, it decreased the inflammation caused by astrocyte secretions (TNF-α, Cox-2, CXCL2). Interestingly, we also observed downregulation of miR-34a and activation of the TAN1/PI3K/CREB signaling pathway. Our data shed light on a previously unsuspected mechanism by which exercise reduces miR-34a levels and protects neuronal function and survival by preventing excessive demyelination and inflammatory infiltration in the CNS.

MicroRNA-5572 Is Associated with Endoplasmic Reticulum Stress Responses in Low Zinc Treated and SOD1 G85R-Transfected HEK293 Cells

Amyotrophic lateral sclerosis (ALS) is a fetal neurodegenerative disease. The mechanism of sporadic ALS onset remains unclarified in detail. Disruption of zinc homeostasis could be related to sporadic ALS. Previously, we first reported miR-5572 as a microRNA (miRNA) among those identified in the spinal cords of patients with sporadic ALS. However, since its function in ALS remained unknown, this study further examined the role of miR-5572 in low-zinc status and ALS model cells which transfected with causative gene, Cu/Zn superoxide dismutase 1 (SOD1) G85R mutant vector. The miR-5572 level was increased by low-zinc condition accompanied by increase of endoplasmic reticulum (ER) stress. In addition, increase of miR-5572 enhanced the cellular toxicity induced by low-zinc treatment. The expression of miR-5572 was also increased, which was accompanied by an increase of ER stress markers associated with SOD1 aggregation formation. Cell death and ER stress makers levels induced by tunicamycin treatment were further increased in miR-5572 mimic-transfected cells. This study showed that miR-5572 exacerbated ER stress toxicity associated with low-zinc status and mutant SOD1 aggregates in ALS.

Current Updates on the Role of MicroRNA in the Diagnosis and Treatment of Neurodegenerative Diseases

BACKGROUND

MicroRNAs (miRNA) are small noncoding RNAs that play a significant role in the regulation of gene expression. The literature has explored the key involvement of miRNAs in the diagnosis, prognosis, and treatment of various neurodegenerative diseases (NDD), such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). The miRNA regulates various signalling pathways; its dysregulation is involved in the pathogenesis of NDD.

OBJECTIVE

The present review is focused on the involvement of miRNAs in the pathogenesis of NDD and their role in the treatment or management of NDD. The literature provides comprehensive and cutting-edge knowledge for students studying neurology, researchers, clinical psychologists, practitioners, pathologists, and drug development agencies to comprehend the role of miRNAs in the NDD's pathogenesis, regulation of various genes/signalling pathways, such as α-synuclein, P53, amyloid-β, high mobility group protein (HMGB1), and IL-1β, NMDA receptor signalling, cholinergic signalling, etc. Methods: The issues associated with using anti-miRNA therapy are also summarized in this review. The data for this literature were extracted and summarized using various search engines, such as Google Scholar, Pubmed, Scopus, and NCBI using different terms, such as NDD, PD, AD, HD, nanoformulations of mRNA, and role of miRNA in diagnosis and treatment.

RESULTS

The miRNAs control various biological actions, such as neuronal differentiation, synaptic plasticity, cytoprotection, neuroinflammation, oxidative stress, apoptosis and chaperone-mediated autophagy, and neurite growth in the central nervous system and diagnosis. Various miRNAs are involved in the regulation of protein aggregation in PD and modulating β-secretase activity in AD. In HD, mutation in the huntingtin (Htt) protein interferes with Ago1 and Ago2, thus affecting the miRNA biogenesis. Currently, many anti-sense technologies are in the research phase for either inhibiting or promoting the activity of miRNA.

CONCLUSION

This review provides new therapeutic approaches and novel biomarkers for the diagnosis and prognosis of NDDs by using miRNA.

Salivary Biomarkers: Noninvasive Ways for Diagnosis of Parkinson's Disease

Finding reliable biomarkers has a crucial role in Parkinson's disease (PD) assessments. Saliva is a bodily fluid, which might be used as a source of biomarkers for PD. Our article has reviewed several publications on salivary proteins in PD patients and their potential as biomarkers. We find out that α-Syn's proportion in oligomeric form is higher in PD patients' saliva, which is potent to use as a biomarker for PD. The salivary concentration of DJ-1 and alpha-amylase is lower in PD patients. Also, substance P level is more moderate in PD patients. Although salivary flow rate is decreased in PD patients, high levels of heme oxygenase and acetylcholinesterase might be used as noninvasive biomarkers. Salivary miRNAs (miR-153, miR-223, miR-874, and miR-145-3p) are novel diagnostic biomarkers that should be given more attention.

The role of exosomes in pathogenesis and the therapeutic efficacy of mesenchymal stem cell-derived exosomes against Parkinson's disease

Parkinson's disease (PD) is a chronic, progressive, neurodegenerative disease. The predominant pathology of PD is the loss of dopaminergic cells in the substantia nigra. Cell transplantation is a strategy with significant potential for treating PD; mesenchymal stem cells (MSCs) are a tremendous therapeutic cell source because they are easily accessible. MSC-derived exosomes with potential protective action in lesioned sites serve as an essential promoter of neuroprotection, and neurodifferentiation, by modulating neural stem cells, neurons, glial cells, and axonal growth in vitro and in vivo environments. The biological properties of MSC-derived exosomes have been proposed as a beneficial tool in different pathological conditions, including PD. Therefore, in this review, we assort the current understanding of MSC-derived exosomes as a new possible therapeutic strategy for PD by providing an overview of the potential role of miRNAs as a component of exosomes in the cellular and molecular basis of PD.

miRNA in Parkinson's disease: From pathogenesis to theranostic approaches

Parkinson's disease (PD) is an age associated neurological disorder which is specified by cardinal motor symptoms such as tremor, stiffness, bradykinesia, postural instability, and non-motor symptoms. Dopaminergic neurons degradation in substantia nigra region and aggregation of αSyn are the classic signs of molecular defects noticed in PD pathogenesis. The discovery of microRNAs (miRNA) predicted to have a pivotal part in various processes regarding regularizing the cellular functions. Studies on dysregulation of miRNA in PD pathogenesis has recently gained the concern where our review unravels the role of miRNA expression in PD and its necessity in clinical validation for therapeutic development in PD. Here, we discussed how miRNA associated with ageing process in PD through molecular mechanistic approach of miRNAs on sirtuins, tumor necrosis factor-alpha and interleukin-6, dopamine loss, oxidative stress and autophagic dysregulation. Further we have also conferred the expression of miRNAs affected by SNCA gene expression, neuronal differentiation and its therapeutic potential with PD. In conclusion, we suggest more rigorous studies should be conducted on understanding the mechanisms and functions of miRNA in PD which will eventually lead to discovery of novel and promising therapeutics for PD.

Electroacupuncture Enhances Cognitive Deficits in a Rat Model of Rapid Eye Movement Sleep Deprivation via Targeting MiR-132

Deprivation of rapid eye movement sleep (REMSD) reduces the potential for learning and memory. The neuronal foundation of cognitive performance is synapse plasticity. MicroRNA-132 (MiR-132) is an important microRNA related to cognitive and synapse plasticity. Acupuncture is effective at improving cognitive impairment caused by sleep deprivation. Furthermore, its underlying principle is still unclear. Herein, whether electroacupuncture (EA) helps alleviate cognitive impairment in REMSD by targeting miR-132 was assessed. A rat model of REMSD was constructed using the developing multiplatform water environment technique, as well as EA therapy in Baihui (GV20) and Dazhui (GV14) was performed for 15 minutes, once daily for 7 days. Agomir or antagomir of MiR-132 was injected into the hippocampal CA1 areas to assess the EA mechanism in rats with REMSD. Then, the learning and memory abilities were detected by behavioral tests; synapse structure was assessed by transmission electron microscope (TCM); and dendrites branches and length were examined by Golgi staining. MiR-132-3p was assessed by real-time quantitative polymerase chain reaction (qRT-PCR). P250GAP, ras-related C3 botulinum toxin substrate 1 (Rac1), and cell division cycle 42 (Cdc42) expression levels in hippocampal tissues were evaluated by immunohistochemistry and Western blot. According to the research, EA therapy enhanced cognitive in REMSD rats, as evidenced by reduced escape latency; upregulated the performance of platform crossings and prolonged duration in the goal region; and improved spontaneous alternation. EA administration restored synaptic and dendritic structural damage in hippocampal neurons, enhanced miR-132 expression, and reduced p250GAP mRNA and protein levels. Additionally, EA boosted the protein level of Rac1 and Cdc42 associated with synaptic plasticity. MiR-132 agomir enhanced this effect, whereas miR-13 antagomir reversed this action. The current data demonstrate that EA at GV20 and GV14 attenuates cognitive impairment and modulates synaptic plasticity in hippocampal neurons via miR-132 in a sleep-deprived rat model.

A comprehensive bioinformatic analysis revealed novel MicroRNA biomarkers of Parkinson's disease

Parkinson's disease (PD) is categorized as a neurodegenerative disorder. Different studies have focused on the role of microRNAs (miRNAs) on PD progression. Due to its complexity in initiation and progression, a considerable requirement has arisen to identify novel miRNA biomarkers in a noninvasive manner. In silico analysis has been used to select differentially expressed miRNAs (DE-miRNAs) and key pathways in this disease. In this manner, several data sets of different neurodegenerative diseases have been analyzed to purify the findings of the present study. Totally, 15 DE miRNAs showed significant changes compared to healthy controls and other neurodegenerative diseases. Then, the targets of the miRNAs were predicted through miRTarBase and TargetScan databases. Besides, enrichment analysis was implemented for predicted target genes. Most of the target genes were enriched in the TRAIL signaling pathway, Regulation of nucleobase, nucleoside, nucleotide and nucleic acid metabolism, protein serine/threonine kinase activity, and Cytoplasm. Moreover, a protein-protein interaction network was constructed to find the most key DE miRNAs and targets in this disease. The results of the present study may help researchers shed light on the discovery of novel biomarkers for PD.

Role of miRNAs in Neurodegeneration: From Disease Cause to Tools of Biomarker Discovery and Therapeutics

Neurodegenerative diseases originate from neuronal loss in the central nervous system (CNS). These debilitating diseases progress with age and have become common due to an increase in longevity. The National Institute of Environmental Health Science’s 2021 annual report suggests around 6.2 million Americans are living with Alzheimer’s disease, and there is a possibility that there will be 1.2 million Parkinson’s disease patients in the USA by 2030. There is no clear-cut universal mechanism for identifying neurodegenerative diseases, and therefore, they pose a challenge for neurobiology scientists. Genetic and environmental factors modulate these diseases leading to familial or sporadic forms. Prior studies have shown that miRNA levels are altered during the course of the disease, thereby suggesting that these noncoding RNAs may be the contributing factor in neurodegeneration. In this review, we highlight the role of miRNAs in the pathogenesis of neurodegenerative diseases. Through this review, we aim to achieve four main objectives: First, we highlight how dysregulation of miRNA biogenesis led to these diseases. Second, we highlight the computational or bioinformatics tools required to identify the putative molecular targets of miRNAs, leading to biological molecular pathways or mechanisms involved in these diseases. Third, we focus on the dysregulation of miRNAs and their target genes leading to several neurodegenerative diseases. In the final section, we highlight the use of miRNAs as potential diagnostic biomarkers in the early asymptomatic preclinical diagnosis of these age-dependent debilitating diseases. Additionally, we discuss the challenges and advances in the development of miRNA therapeutics for brain targeting. We list some of the innovative strategies employed to deliver miRNA into target cells and the relevance of these viral and non-viral carrier systems in RNA therapy for neurodegenerative diseases. In summary, this review highlights the relevance of studying brain-enriched miRNAs, the mechanisms underlying their regulation of target gene expression, their dysregulation leading to progressive neurodegeneration, and their potential for biomarker marker and therapeutic intervention. This review thereby highlights ways for the effective diagnosis and prevention of these neurodegenerative disorders in the near future.

Extracellular Vesicles, Stem Cells and the Role of miRNAs in Neurodegeneration

There are different modalities of intercellular communication governed by cellular homeostasis. In this review, we will explore one of these forms of communication called extracellular vesicles (EVs). These vesicles are released by all cells in the body and are heterogeneous in nature. The primary function of EVs is to share information through their cargo consisting of proteins, lipids and nucleic acids (mRNA, miRNA, dsDNA etc.) with other cells, which have a direct consequence on their microenvironment. We will focus on the role of EVs of mesenchymal stem cells (MSCs) in the nervous system and how these participate in intercellular communication to maintain physiological function and provide neuroprotection. However, deregulation of this same communication system could play a role in several neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, multiple sclerosis, prion disease and Huntington's disease. The release of EVs from a cell provides crucial information to what is happening inside the cell and thus could be used in diagnostics and therapy. We will discuss and explore new avenues for the clinical applications of using engineered MSC-EVs and their potential therapeutic benefit in treating neurodegenerative diseases.

SNCA 3' UTR Genetic Variants in Patients with Parkinson's Disease

The SNCA (Synuclein Alpha) gene represents a major risk gene for Parkinson's disease (PD) and SNCA polymorphisms have been associated with the common sporadic form of PD. Numerous Genome-Wide Association Studies showed strong signals located in the SNCA 3' UTR (untranslated region) region indicating that variants in 3' UTRs of PD-associated genes could contribute to neurodegeneration and may regulate the risk for PD. Genetic variants in 3' UTR can affect miRNA activity and consequently change the translation process. The aim of this study was to access the differences in 3' UTR variants of SNCA genes in a cohort of PD patients and control subjects from Croatia. The cohort consisted of 52 PD patients and 23 healthy control subjects. Differences between 3' UTR allele and genotype frequencies were accessed through next generation sequencing approach from whole blood samples. In our study, we identified four previously reported single nucleotide polymorphisms (SNPs) and one insertion in the 3' UTR region of SNCA gene, namely rs1045722, rs3857053, rs577490090, rs356165, and rs777296100, and five variants not reported in the literature, namely rs35270750, rs529553259, rs377356638, rs571454522, and rs750347645. Our results indicate a significantly higher occurrence of the rs571454522 variant in the PD population. To the best of our knowledge, this variant has not been reported until now in the literature. We analyzed our results in the context of previous research, creating a brief overview of the importance of 3' UTR variants of the SNCA gene. Further studies will be needed to gain a more profound insight regarding their role in PD development, which will help to assess the role and impact of post-transcriptional regulation on disease pathology.

Parkinson's disease and microRNAs - Lessons from model organisms and human studies

Parkinson's disease (PD) is a progressive, age-associated neurodegenerative disorder that affects an estimated 10 million people worldwide. PD is characterized by proteinaceous, cytoplasmic inclusions containing α-synuclein, called Lewy Bodies, which form in dopaminergic neurons in an age-dependent manner, and are associated with the emergence of characteristic PD symptoms such as resting tremor, rigidity, slow movements and postural instability. Although considerable progress has been made in recent years in identifying genetic and environmental factors that are associated with PD, early diagnosis and therapeutic options remain severely lacking. Recently, microRNAs (miRNAs) have emerged as novel therapeutic targets in various diseases, such as cancer and neurodegenerative diseases. MiRNAs have been shown to play roles in various aging and neurodegenerative disease models across phyla. More recently, studies have identified specific roles for miRNAs and their targets in the pathogenesis and progression of PD in several model organisms. Here, we discuss the evolving field of miRNAs, their association with PD, and the outlook for the future.

The role of microRNAs in diseases and related signaling pathways

MicroRNAs (miRNAs) are epigenetic regulators of the gene expression and act through posttranslational modification. They bind to 3'-UTR of target mRNAs to inhibit translation or increase the degradation mRNA in many tissues. Any alteration in the level of miRNA expression in many human diseases indicates their involvement in the pathogenesis of many diseases. On the other hand, the regulation of the signaling pathways is necessary for the maintenance of natural and physiological characteristics of any cell. It is worth mentioning that dysfunction of the signaling pathways manifests itself as a disorder or disease. The significant evidence report that miRNAs regulate the several signaling pathways in many diseases. Base on previous studies, miRNAs can be used for therapeutic or diagnostic purposes. According to the important role of miRNAs on the cell signaling pathways, this article reviews miRNAs involvement in incidence of diseases by changing signaling pathways.

Circulating Biomarkers in Neuromuscular Disorders: What Is Known, What Is New

The urgent need for new therapies for some devastating neuromuscular diseases (NMDs), such as Duchenne muscular dystrophy or amyotrophic lateral sclerosis, has led to an intense search for new potential biomarkers. Biomarkers can be classified based on their clinical value into different categories: diagnostic biomarkers confirm the presence of a specific disease, prognostic biomarkers provide information about disease course, and therapeutic biomarkers are designed to predict or measure treatment response. Circulating biomarkers, as opposed to instrumental/invasive ones (e.g., muscle MRI or nerve ultrasound, muscle or nerve biopsy), are generally easier to access and less “time-consuming”. In addition to well-known creatine kinase, other promising molecules seem to be candidate biomarkers to improve the diagnosis, prognosis and prediction of therapeutic response, such as antibodies, neurofilaments, and microRNAs. However, there are some criticalities that can complicate their application: variability during the day, stability, and reliable performance metrics (e.g., accuracy, precision and reproducibility) across laboratories. In the present review, we discuss the application of biochemical biomarkers (both validated and emerging) in the most common NMDs with a focus on their diagnostic, prognostic/predictive and therapeutic application, and finally, we address the critical issues in the introduction of new biomarkers.

Dysregulation of miRNA in Leukemia: Exploiting miRNA Expression Profiles as Biomarkers

Micro RNAs (miRNAs) are a class of small non-coding RNAs that have a crucial role in cellular processes such as differentiation, proliferation, migration, and apoptosis. miRNAs may act as oncogenes or tumor suppressors; therefore, they prevent or promote tumorigenesis, and abnormal expression has been reported in many malignancies. The role of miRNA in leukemia pathogenesis is still emerging, but several studies have suggested using miRNA expression profiles as biomarkers for diagnosis, prognosis, and response to therapy in leukemia. In this review, the role of miRNAs most frequently involved in leukemia pathogenesis is discussed, focusing on the class of circulating miRNAs, consisting of cell-free RNA molecules detected in several body fluids. Circulating miRNAs could represent new potential non-invasive diagnostic and prognostic biomarkers of leukemia that are easy to isolate and characterize. The dysregulation of some miRNAs involved in both myeloid and lymphoid leukemia, such as miR-155, miR-29, let-7, and miR-15a/miR-16-1 clusters is discussed, showing their possible employment as therapeutic targets.

Voluntary wheel-running exercise attenuates brain aging of rats through activating miR-130a-mediated autophagy

Autophagy is a highly regulated intracellular process for the degradation of protein aggregates and damaged organelles. Recently, autophagy has been implicated in Alzheimer's disease (AD) and aging. Autophagy process is regulated by the recruitment and assembly of several autophagy-related genes (Atgs) such as, Atg7 and LC3, as the highly conserved and important markers involved in the regulation of autophagy. We recently reported the reduced LC3-II/LC3-I ratio, down-regulated ATG7, and increased p62 protein levels in hippocampal tissues of aging rats. MicroRNA-130a (miR-130a) plays a crucial role in physiological and pathological processes, but whether miR-130a affects the autophagy of brain is unknown. We aim to explore the regulatory role of miR-130a on the autophagy and cell senescence of SH-SY5Y, as well as LC3-II/LC3-I ratio, and the expression of p62, ATG7, Ac-p53 and p21 during exercise intervention of aging rats. In this study, miR-130a expression was markedly down-regulated in the hippocampal of aged rats companying with up-regulated expression of Ac-p53 and p21 when compared with young rats. In contrast, voluntary wheel running could up-regulate miR-130a expression; decrease the expression of Ac-p53 and p21 in aging rats. Interestingly, exercise reversed the impaired autophagy resulted from aging possibly by activating AMPK signaling. Moreover, overexpression of miR-130a in d-galactose (D-gal)-induced SH-SY5Y cell senescence model attenuated d-gal-induced impaired autophagy and cell senescence, demonstrated by decreased levels of LC3, Ac-p53, p21 and increased p62, suggesting that voluntary wheel running can alleviate brain aging in natural aging rats by up-regulating miR-130a-mediated autophagy.

The pleiotropic neuroprotective effects of resveratrol in cognitive decline and Alzheimer's disease pathology: From antioxidant to epigenetic therapy

While the elderly segment of the population continues growing in importance, neurodegenerative diseases increase exponentially. Lifestyle factors such as nutrition, exercise, and education, among others, influence ageing progression, throughout life. Notably, the Central Nervous System (CNS) can benefit from nutritional strategies and dietary interventions that prevent signs of senescence, such as cognitive decline or neurodegenerative diseases such as Alzheimer's disease and Parkinson's Disease. The dietary polyphenol Resveratrol (RV) possesses antioxidant and cytoprotective effects, producing neuroprotection in several organisms. The oxidative stress (OS) occurs because of Reactive oxygen species (ROS) accumulation that has been proposed to explain the cause of the ageing. One of the most harmful effects of ROS in the cell is DNA damage. Nevertheless, there is also evidence demonstrating that OS can produce other molecular changes such as mitochondrial dysfunction, inflammation, apoptosis, and epigenetic modifications, among others. Interestingly, the dietary polyphenol RV is a potent antioxidant and possesses pleiotropic actions, exerting its activity through various molecular pathways. In addition, recent evidence has shown that RV mediates epigenetic changes involved in ageing and the function of the CNS that persists across generations. Furthermore, it has been demonstrated that RV interacts with gut microbiota, showing modifications in bacterial composition associated with beneficial effects. In this review, we give a comprehensive overview of the main mechanisms of action of RV in different experimental models, including clinical trials and discuss how the interconnection of these molecular events could explain the neuroprotective effects induced by RV.

Perspectives on Epigenetics Alterations Associated with Smoking and Vaping

Epigenetic alterations, including DNA methylation, microRNA, and long noncoding RNA, play important roles in the pathogenesis of numerous respiratory health conditions and diseases. Exposure to tobacco smoking has been found to be associated with epigenetic changes in the respiratory tract. Marketed as a less harmful alternative to combustible cigarettes, electronic cigarette (e-cigarette) has rapidly gained popularity in recent years, especially among youth and young adults. Accumulative evidence from both animal and human studies has shown that e-cigarette use (vaping) is also linked to similar respiratory health conditions as observed with cigarette smoking, including wheezing, asthma, and COPD. This review aims to provide an overview of current studies on associations of smoking and vaping with epigenetic alterations in respiratory cells and provide future research directions in epigenetic studies related to vaping.

Dysregulation of MicroRNAs and PIWI-Interacting RNAs in a Caenorhabditis elegans Parkinson's Disease Model Overexpressing Human α-Synuclein and Influence of tdp-1

MicroRNAs (miRNAs) and PIWI-interacting RNAs (piRNAs) regulate gene expression and biological processes through specific genetic and epigenetic mechanisms. Recent studies have described a dysregulation of small non-coding RNAs in Parkinson’s disease (PD) tissues but have been limited in scope. Here, we extend these studies by comparing the dysregulation of both miRNAs and piRNAs from transgenic Caenorhabditis elegans (C. elegans) nematodes overexpressing pan-neuronally human α-synuclein wild-type (WT) (HASN^WT OX) or mutant (HASN^A53T OX). We observed 32 miRNAs and 112 piRNAs dysregulated in HASN^A53T OX compared with WT. Genetic crosses of HASN^A53T OX PD animal models with tdp-1 null mutants, the C. elegans ortholog of TDP-43, an RNA-binding protein aggregated in frontal temporal lobar degeneration, improved their behavioral deficits and changed the number of dysregulated miRNAs to 11 and piRNAs to none. Neuronal function-related genes T28F4.5, C34F6.1, C05C10.3, camt-1, and F54D10.3 were predicted to be targeted by cel-miR-1018, cel-miR-355-5p (C34F6.1 and C05C10.3), cel-miR-800-3p, and 21ur-1581 accordingly. This study provides a molecular landscape of small non-coding RNA dysregulation in an animal model that provides insight into the epigenetic changes, molecular processes, and interactions that occur during PD-associated neurodegenerative disorders.

Inhibition of miR-96-5p in the mouse brain increases glutathione levels by altering NOVA1 expression

Glutathione (GSH) is an important antioxidant that plays a critical role in neuroprotection. GSH depletion in neurons induces oxidative stress and thereby promotes neuronal damage, which in turn is regarded as a hallmark of the early stage of neurodegenerative diseases. The neuronal GSH level is mainly regulated by cysteine transporter EAAC1 and its inhibitor, GTRAP3-18. In this study, we found that the GTRAP3-18 level was increased by up-regulation of the microRNA miR-96-5p, which was found to decrease EAAC1 levels in our previous study. Since the 3'-UTR region of GTRAP3-18 lacks the consensus sequence for miR-96-5p, an unidentified protein should be responsible for the intermediate regulation of GTRAP3-18 expression by miR-96-5p. Here, we discovered that RNA-binding protein NOVA1 functions as an intermediate protein for GTRAP3-18 expression via miR-96-5p. Moreover, we show that intra-arterial injection of a miR-96-5p-inhibiting nucleic acid to living mice by a drug delivery system using microbubbles and ultrasound decreased the level of GTRAP3-18 via NOVA1 and increased the levels of EAAC1 and GSH in the dentate gyrus of the hippocampus. These findings suggest that the delivery of a miR-96-5p inhibitor to the brain would efficiently increase the neuroprotective activity by increasing GSH levels via EAAC1, GTRAP3-18 and NOVA1.

The role of exosomal microRNAs in central nervous system diseases

MicroRNAs (miRNA), endogenous non-coding RNAs approximately 22 nucleotides long, regulate gene expression by mediating translational inhibition or mRNA degradation. Exosomes are a tool for intercellular transmission of information in which miRNA exchange plays an important role. Under pathophysiological conditions in the central nervous system (CNS), cellular transmission of exosomal miRNAs can regulate signaling pathways. Exosomal miRNAs are involved in the occurrence and development of diverse CNS diseases, such as traumatic brain injury, spinal cord injury, stroke, neurodegenerative diseases, epilepsy, and glioma. The use of exosomes as transport vehicles for certain miRNAs provides a novel therapeutic strategy for CNS diseases. Furthermore, the exosomes in body fluids change with the occurrence of diseases, indicating that subtle changes in physiological and pathological processes in vivo could be recognized by analyzing exosomes. Exosomal analysis is expected to act as a novel tool for diagnosis and prediction of neurological diseases. In this review, we present the current understanding of the implications of miRNAs in CNS diseases and summarize the role and mechanism of action of exosomal miRNA in nervous system disease models.

Downregulation of microRNA-15b-5p Targeting the Akt3-Mediated GSK-3β/β-Catenin Signaling Pathway Inhibits Cell Apoptosis in Parkinson's Disease

Parkinson's disease (PD) is an incurable progressive disorder resulting from neurodegeneration, and apoptosis is considered a dominant mechanism underlying the process of neurodegeneration. MicroRNAs (miRNAs), which are small and noncoding RNAs involved in many a biological process like apoptosis and regulation of gene expressions, have been found in postmortem brain samples of patients with PD, as well as in vitro and in vivo models of PD. To explore the impact of miR-15b-5p and Akt3 on apoptosis in the progression of PD, the method of quantitative reverse transcription polymerase chain reaction (qRT-PCR) was employed, and the analysis result showed upregulated expression of miR-15b-5p and downregulated expression of Akt3 in the serum of PD patients, MPP+-induced SH-SY5Y cells, and the brain tissues of MPTP-induced mice. Meanwhile, the dual-luciferase reporter assay was used to demonstrate the regulator-target interaction between miR-15b-5p and Akt3; flow cytometry and spectrophotometry revealed that transfection of miR-15b-5p mimic and si-Akt3 increased the rate of apoptosis and caspase-3 activity, whereas transfecting the miR-15b-5p inhibitor and Akt3-overexpression plasmid repressed the rate of apoptosis and caspase-3 activity in the MPP+-induced SH-SY5Y cell model and the MPTP-induced mouse model. Additionally, analysis of western blotting (WB) assays in vivo and in vitro revealed that proapoptosis proteins (Bax, caspase-3, GSK-3β, and β-catenin) showed markedly upregulated expression in the miR-15b-5p inhibitor and si-Akt3-overexpression groups, while the expression of an antiapoptosis gene (i.e., Bcl2) was downregulated. These analysis results indicate that downregulation of miR-15b-5p by targeting the Akt3-mediated GSK-3β/β-catenin signaling pathway would repress cell apoptosis in PD in vivo and in vitro. It is expected that the research findings would help find new therapeutic targets for treatment of PD.

Circulating microRNAs as potential biomarkers and therapeutic targets in spinal muscular atrophy

Spinal muscular atrophy (SMA), a leading genetic cause of infant death, is a neurodegenerative disease characterized by the selective loss of particular groups of motor neurons (MNs) in the anterior horn of the spinal cord with progressive muscle wasting. SMA is caused by a deficiency of the survival motor neuron (SMN) protein due to a homozygous deletion or mutation of the SMN1 gene. However, the molecular mechanisms whereby the SMN complex regulates MN functions are not fully elucidated. Emerging studies on SMA pathogenesis have turned the attention of researchers to RNA metabolism, given that increasingly identified SMN-associated modifiers are involved in both coding and non-coding RNA (ncRNA) processing. Among various ncRNAs, microRNAs (miRNAs) are the most studied in terms of regulation of posttranscriptional gene expression. Recently, the discovery that miRNAs are critical to MN function and survival led to the study of dysregulated miRNAs in SMA pathogenesis. Circulating miRNAs have drawn attention as a readily available biomarker due to their property of being clinically detectable in numerous human biofluids through non-invasive approaches. As there are recent promising findings from novel miRNA-based medicines, this article presents an extensive review of the most up-to-date studies connecting specific miRNAs to SMA pathogenesis and the potential applications of miRNAs as biomarkers and therapeutic targets for SMA.

Exosomal miRNAs as Potential Diagnostic Biomarkers in Alzheimer's Disease

Alzheimer’s disease (AD), a neurodegenerative disease, is linked to a variety of internal and external factors present from the early stages of the disease. There are several risk factors related to the pathogenesis of AD, among these exosomes and microRNAs (miRNAs) are of particular importance. Exosomes are nanocarriers released from many different cell types, including neuronal cells. Through the transfer of bioactive molecules, they play an important role both in the maintenance of physiological and in pathological conditions. Exosomes could be carriers of potential biomarkers useful for the assessment of disease progression and for therapeutic applications. miRNAs are small noncoding endogenous RNA sequences active in the regulation of protein expression, and alteration of miRNA expression can result in a dysregulation of key genes and pathways that contribute to disease development. Indeed, the involvement of exosomal miRNAs has been highlighted in various neurodegenerative diseases, and this opens the possibility that dysregulated exosomal miRNA profiles may influence AD disease. The advances in exosome-related biomarker detection in AD are summarized. Finally, in this review, we highlight the use of exosomal miRNAs as essential biomarkers in preclinical and clinical studies in Alzheimer’s disease, also taking a look at their potential clinical value.

Evolution of a Human-Specific Tandem Repeat Associated with ALS

Tandem repeats are proposed to contribute to human-specific traits, and more than 40 tandem repeat expansions are known to cause neurological disease. Here, we characterize a human-specific 69 bp variable number tandem repeat (VNTR) in the last intron of WDR7, which exhibits striking variability in both copy number and nucleotide composition, as revealed by long-read sequencing. In addition, greater repeat copy number is significantly enriched in three independent cohorts of individuals with sporadic amyotrophic lateral sclerosis (ALS). Each unit of the repeat forms a stem-loop structure with the potential to produce microRNAs, and the repeat RNA can aggregate when expressed in cells. We leveraged its remarkable sequence variability to align the repeat in 288 samples and uncover its mechanism of expansion. We found that the repeat expands in the 3'-5' direction, in groups of repeat units divisible by two. The expansion patterns we observed were consistent with duplication events, and a replication error called template switching. We also observed that the VNTR is expanded in both Denisovan and Neanderthal genomes but is fixed at one copy or fewer in non-human primates. Evaluating the repeat in 1000 Genomes Project samples reveals that some repeat segments are solely present or absent in certain geographic populations. The large size of the repeat unit in this VNTR, along with our multiplexed sequencing strategy, provides an unprecedented opportunity to study mechanisms of repeat expansion, and a framework for evaluating the roles of VNTRs in human evolution and disease.

MicroRNAs Dysregulation and Mitochondrial Dysfunction in Neurodegenerative Diseases

Neurodegenerative diseases are debilitating and currently incurable conditions causing severe cognitive and motor impairments, defined by the progressive deterioration of neuronal structure and function, eventually causing neuronal loss. Understand the molecular and cellular mechanisms underlying these disorders are essential to develop therapeutic approaches. MicroRNAs (miRNAs) are short non-coding RNAs implicated in gene expression regulation at the post-transcriptional level. Moreover, miRNAs are crucial for different processes, including cell growth, signal transmission, apoptosis, cancer and aging-related neurodegenerative diseases. Altered miRNAs levels have been associated with the formation of reactive oxygen species (ROS) and mitochondrial dysfunction. Mitochondrial dysfunction and ROS formation occur in many neurodegenerative diseases such as Alzheimer's, Parkinson's and Huntington's diseases. The crosstalk existing among oxidative stress, mitochondrial dysfunction and miRNAs dysregulation plays a pivotal role in the onset and progression of neurodegenerative diseases. Based on this evidence, in this review, with a focus on miRNAs and their role in mitochondrial dysfunction in aging-related neurodegenerative diseases, with a focus on their potential as diagnostic biomarkers and therapeutic targets.

Dihydroquercetin attenuates lipopolysaccharide-induced acute lung injury through modulating FOXO3-mediated NF-κB signaling via miR-132-3p

BACKGROUND

Dihydroquercetin (DHQ) is a potent flavonoid which has been demonstrated to have multiple biological activities including anti-inflammation activity, antioxidant activity as well as anti-cancer activity etc. Recently, many studies have focused on the antioxidant activity of DHQ. However, the use of the anti-inflammation activity of DHQ in acute lung injury (ALI) has not been reported.

METHODS

Cell viability was examined by CCK-8 assay. The relative expression of miR-132-3p, FOXO3 were detected by qPCR. The levels of TNF-α, IL-6 and IL-1β were detected using enzyme-linked immunosorbent assay. The amount of apoptosis cells was detected by flow cytometry. The protein levels of Bcl-2, Bax, p-p65 and p-IκBα were measured by western blot.

RESULTS

We found that DHQ-induced the expression of miR-132-3p in LPS-induced ALI. Overexpression of miR-132-3p resulted in the inhibition of FOXO3 expression and then suppressed FOXO3-activated NF-κB pathway, attenuating LPS-induced inflammatory response and apoptosis.

CONCLUSION

We demonstrated FOXO3 to be a target of miR-132-3p, and DHQ could induce the expression of miR-132-3p, relieving LPS-induced ALI via miR-132-3p/FOXO3/NF-κB axis, providing a promising therapeutic target for ALI.

A blood miRNA signature associates with sporadic Creutzfeldt-Jakob disease diagnosis

Sporadic Creutzfeldt-Jakob disease (sCJD) presents as a rapidly progressive dementia which is usually fatal within six months. No clinical blood tests are available for diagnosis or disease monitoring. Here, we profile blood microRNA (miRNA) expression in sCJD. Sequencing of 57 sCJD patients, and healthy controls reveals differential expression of hsa-let-7i-5p, hsa-miR-16-5p, hsa-miR-93-5p and hsa-miR-106b-3p. Downregulation of hsa-let-7i-5p, hsa-miR-16-5p and hsa-miR-93-5p replicates in an independent cohort using quantitative PCR, with concomitant upregulation of four mRNA targets. Absence of correlation in cross-sectional analysis with clinical phenotypes parallels the lack of association between rate of decline in miRNA expression, and rate of disease progression in a longitudinal cohort of samples from 21 patients. Finally, the miRNA signature shows a high level of accuracy in discriminating sCJD from Alzheimer’s disease. These findings highlight molecular alterations in the periphery in sCJD which provide information about differential diagnosis and improve mechanistic understanding of human prion diseases.

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rapidly progressive dementia. No clinical blood tests are available for diagnosis. The authors identified three miRNAs in whole-blood that are downregulated in sCJD patients, and discriminate sCJD from Alzheimer’s disease patients and healthy controls.

miRNA target identification and prediction as a function of time in gene expression data

The understanding of miRNA target interactions is still limited due to conflicting data and the fact that high-quality validation of targets is a time-consuming process. Faster methods like high-throughput screens and bioinformatics predictions are employed but suffer from several problems. One of these, namely the potential occurrence of downstream (i.e. secondary) effects in high-throughput screens has been only little discussed so far. However, such effects limit usage for both the identification of interactions and for the training of bioinformatics tools. In order to analyse this problem more closely, we performed time-dependent microarray screening experiments overexpressing human miR-517a-3p, and, together with published time-dependent datasets of human miR-17-5p, miR-135b and miR-124 overexpression, we analysed the dynamics of deregulated genes. We show that the number of deregulated targets increases over time, whereas seed sequence content and performance of several miRNA target prediction algorithms actually decrease over time. Bioinformatics recognition success of validated miR-17 targets was comparable to that of data gained only 12 h post-transfection. We therefore argue that the timing of microarray experiments is of critical importance for detecting direct targets with high confidence and for the usability of these data for the training of bioinformatics prediction tools.

MicroRNA-5572 Is a Novel MicroRNA-Regulating SLC30A3 in Sporadic Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive degenerative disease caused by the loss of motor neurons. Although the pathogenesis of sporadic ALS (sALS) remains unclear, it has recently been suggested that disorders of microRNA (miRNA) may be involved in neurodegenerative conditions. The purpose of this study was to investigate miRNA levels in sALS and the target genes of miRNA. Microarray and real-time RT-PCR analyses revealed significantly-decreased levels of miR-139-5p and significantly increased levels of miR-5572 in the spinal cords of sALS patients compared with those in controls. We then focused on miR-5572, which has not been reported in ALS, and determined its target gene. By using TargetScan, we predicted SLC30A3 as the candidate target gene of miR-5572. In a previous study, we found decreased SLC30A3 levels in the spinal cords of sALS patients. We revealed that SLC30A3 was regulated by miR-5572. Taken together, these results demonstrate that the level of novel miRNA miR-5572 is increased in sALS and that SLC30A3 is one of the target genes regulated by miR-5572.

Droplet digital polymerase chain reaction-based quantification of circulating microRNAs using small RNA concentration normalization

Quantification of plasma microRNAs (miRNAs) as non-invasive disease biomarkers is subject to multiple technical variabilities. This study aimed to develop an optimized protocol for miRNA quantification from rodent plasma. We hypothesized that a fixed small RNA concentration input for reverse transcription (RT) reaction will provide better miRNA quantification than a fixed RNA volume input. For this, tail-vein plasma was collected from 30 naïve, adult male Sprague-Dawley rats. Plasma hemolysis was measured with NanoDrop-1000 and Denovix DS-11 spectrophotometers. Plasma was then pooled, and RNA was extracted from 50-μl, 100-μl or 200-μl pool aliquots. Small RNA concentration was measured with Qubit miRNA assay. A fixed RNA volume (un-normalized) or a fixed small RNA concentration was used for RT (concentration-normalized). The method was setup with miR-23a-3p and validated with miR-103a-3p and miR-451a. Hemolysis measurements from Denovix and NanoDrop strongly correlated. Qubit revealed increased small RNA concentrations with increasing starting plasma volumes. With concentration-normalization, miRNA levels from 100-µl and 200-µl plasma volume groups mostly normalized to the level of the 50-µl in ddPCR. Our results indicate that miRNA quantification with ddPCR should be performed with small RNA concentration-normalization to minimize variations in eluted RNA concentrations occuring during RNA extraction.

MicroRNAs alteration as early biomarkers for cancer and neurodegenerative diseases: New challenges in pesticides exposure

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Current knowledge linking pesticide exposure, cancer and neuro-degenerative diseases to dysregulation of microRNA network was summarized.

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Literature indicates differential miRNA expression targeting biomolecules and pathways involved in cancer and neurodegenerative diseases.

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Evaluation of miRNA expression may be used to develop new non-invasive strategies for the prediction and prognosis of diseases including cancer.

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The application of miRNAs as diagnostic and therapeutic biomarkers in the clinical field is extremely challenging.

This review summarizes the current knowledge linking cancer and neuro-degenerative diseases to dysregulation of microRNA network following pesticide exposure. Most findings revealed differential miRNA expression targeting biomolecules and pathways involved in various neoplastic localizations and neurodegenerative diseases.

A growing body of evidence in recent literature indicates that alteration of specific miRNAs can represent an early biomarker of disease following exposure to chemical agents, including pesticides. Different miRNAs seem to regulate cell proliferation, apoptosis, migration, invasion, and metastasis via many biological pathways through modulation of the expression of target mRNAs.

The evaluation of miRNA expression levels may be used to develop new non-invasive strategies for the prediction and prognosis of many diseases, including cancer. However, the application of miRNAs as diagnostic and therapeutic biomarkers in the clinical field is extremely challenging.

Cytoplasmic TDP43 Binds microRNAs: New Disease Targets in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive, fatal, and incurable neurodegenerative disease. Recent studies suggest that dysregulation of gene expression by microRNAs (miRNAs) may play an important role in ALS pathogenesis. The reversible nature of this dysregulation makes miRNAs attractive pharmacological targets and a potential therapeutic avenue. Under physiological conditions, miRNA biogenesis, which begins in the nucleus and includes further maturation in the cytoplasm, involves trans-activation response element DNA/RNA-binding protein of 43 kDa (TDP43). However, TDP43 mutations or stress trigger TDP43 mislocalization and inclusion formation, a hallmark of most ALS cases, that may lead to aberrant protein/miRNA interactions in the cytoplasm. Herein, we demonstrated that TDP43 exhibits differential binding affinity for select miRNAs, which prompted us to profile miRNAs that preferentially bind cytoplasmic TDP43. Using cellular models expressing TDP43 variants and miRNA profiling analyses, we identified differential levels of 65 cytoplasmic TDP43-associated miRNAs. Of these, approximately 30% exhibited levels that differed by more than 3-fold in the cytoplasmic TDP43 models relative to our control model. The hits included both novel miRNAs and miRNAs previously associated with ALS that potentially regulate several predicted genes and pathways that may be important for pathogenesis. Accordingly, these findings highlight specific miRNAs that may shed light on relevant disease pathways and could represent potential biomarkers and reversible treatment targets for ALS.

Differential Expression of Plasma Exo-miRNA in Neurodegenerative Diseases by Next-Generation Sequencing

Neurodegenerative diseases encompass a wide variety of pathological conditions caused by a loss of neurons in the central nervous system (CNS) and are severely debilitating. Exosome contains bio-signatures of great diagnostic and therapeutic value. There is proof that exosomal proteins can be biomarkers for Alzheimer’s disease (AD) and Parkinson’s disease (PD). MicroRNAs in exosome has potential to be an important source of biomarkers for neurodegenerative diseases. Here, we report exosomal microRNA performance of human plasma in neurodegenerative diseases by small RNA sequencing. A wide range of altered exo-miRNA expression levels were detected in both AD and PD patients. Down-regulated miRNAs in AD samples were enriched in ECM-receptor interaction pathway and both up-/down-regulated miRNAs in PD samples were enriched in fatty acid biosynthesis pathway. Compared to the control, 8 miRNAs were found to be significantly elevated/declined in AD and PD samples, of which 4 miRNAs were newly identified. Additionally, two exosome isolating methods were compared and the reproducibility of plasma exo-miRNA expression was confirmed, suggesting the feasibility of large-scale clinical application of this method. This study revealed exo-miRNA expression levels in neurodegenerative diseases, proposed new biomarkers and their potential functional pathway for AD and PD, confirmed the reproductivity of exo-miRNA profiles by using a different exosome isolating method, and compared the results with plasma miRNA expression. Therefore, this study also provides a precedent for identifying exosomal biomarkers of neurodegenerative diseases in plasma by high-throughput sequencing and it could extend the therapeutic repertoire of exosomal biomarkers.

miR-30b protects nigrostriatal dopaminergic neurons from MPP(+)-induced neurotoxicity via SNCA

OBJECTIVE

To explore the function of miR-30b in pathogenesis of Parkinson's disease (PD) and its underlying molecular mechanism.

MATERIALS AND METHODS

We used 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPP(+)) as a tool for constructing the PD cell model, using miR-30b mimics or inhibitors to manipulate miR-30b level for an experimental model of acquisition. The cell viability of SH-SY5Y was detected by CCK, and luciferase was used to screen the binding of target genes. The protein levels of SNCA were measured by Western blot. Then, we investigate the changes in pro- and anti-apoptotic markers with or without miR-30b treatment.

RESULTS

There was a significant low expression of MiR-30b in MPP(+)-induced cells. SH-SY5Y cell viability was rescued by MiR-30b overexpression. Luciferase experiments showed that MiR-30b may bind to the 3'-UTR side of SNCA and inhibited its expression. By Western blot, the SNCA level was markedly decreased by miR-30b. miR-30b attenuated the upregulation of Bax and the depletion of Bcl-2 induced by MPP(+).

Methylglyoxal-induced miR-223 suppresses rat vascular KATP channel activity by downregulating Kir6.1 mRNA in carbonyl stress

The vascular ATP-sensitive K⁺ (K_ATP) channel composed of Kir6.1 and SUR2B subunits regulates cellular activity by coupling intermediary metabolism to membrane excitability. Our previous studies have shown that both Kir6.1 and SUB2B are post-transcriptionally downregulated by methylglyoxal (MGO) which is a reactive carbonyl specie and can cause disruption of vascular tone regulation under diabetic conditions. We have shown that the SUB2B downregulation is mediated by the microRNA (miR) miR-9a, while the mechanism underlying Kir6.1 inhibition is still unclear. Studying the microRNA databases, we found that miR-223 has sequence similarities to the 3' untranslated sequence (3'UTR) of Kir6.1 mRNA suggesting their potential interactions. Therefore, we explored the role of miR-233 in K_ATP channel regulation by up/down-regulation of miR-223 in smooth muscle cells (SMCs) and mesenteric arterials. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis showed augmentation of miR-223 expression in the cultured SMCs after 300 μM MGO exposure by 5-6 folds. miR-223 overexpression down-regulated Kir6.1 mRNA levels by ~2.6 times while miR-223 knockdown diminished the effect of 300 μM MGO by ~50% in the SMCs. Luciferase assay and mutagenesis studies showed that the effect of miR-223 was abolished when the potential interaction site in the 3' UTR was mutated. Studies with Western blot, patch clamp, and perfused mesenteric arterial rings showed that transfection of miR-223 downregulated K_ATP protein expression, inhibited K_ATP channel activity and enhanced vasoconstriction. These results therefore suggest that miR-223 is induced by MGO exposure, which subsequently downregulates the Kir6.1 mRNA, suppresses K_ATP channel function, and impairs functional regulation of vascular tones.

BACKGROUND

Methylglyoxal causes transcriptional inhibition of the vascular K_ATP channel.

RESULTS

Exogenous miR-223 down-regulated Kir6.1. miR-223 knockdown alleviated the effect of MGO.

CONCLUSION

Vascular K_ATP channel is important for miR-223 targeting.

SIGNIFICANCE

Regulation of the miR-223 level may be a novel strategy for clinical treatment of diabetes.

Deiodinases, organic anion transporter polypeptide polymorphisms and ischemic stroke outcomes

BACKGROUND

Ischemic stroke is a major cause of premature death and chronic disability worldwide, and individual variation in functional outcome is strongly influenced by genetic factors. Neuroendocrine signaling by the hypothalamic-hypophyseal-thyroid axis is a critical regulator of post-stroke pathogenesis, suggesting that allelic variants in thyroid hormone (TH) signaling can influence stroke outcome.

AIM

To examine associations between acute ischemic stroke (AIS) outcome and allelic variants of the TH metabolizing enzymes deiodinase type 1-3 (DIO1-3) and membrane transporting organic anion polypeptide C1 (OATP1C1).

METHODS

Eligible AIS patients from Lithuania (n = 248) were genotyped for ten DIO1-3 and OATP1C1 single nucleotide polymorphisms (SNPs): DIO1 rs12095080-A/G, rs11206244-C/T, and rs2235544-A/C; DIO2 rs225014-T/C and rs225015-G/A; DIO3 rs945006-T/G; OATP1C1 rs974453-G/A, rs10444412-T/C, rs10770704-C/T, and rs1515777-A/G. Functional outcome was evaluated one year after index AIS using the modified Rankin Scale. Analyses were adjusted for important confounders, including serum free triiodothyronine.

RESULTS

After adjustment for potential confounders, the major allelic (wild-type) DIO3 genotype rs945006-TT was associated with better 1-year AIS functional outcome (odds ratio [OR] = 0.25; 95% confidence interval [CI]: 0.08-0.74; p = .013), while the wild-type OATP1C1 genotype rs10770704-CC was associated with poorer outcome (OR = 2.00, 95%CI: 1.04-3.86; p = .038).

CONCLUSION

Allelic variants in thyroid axis genes may prove useful for prognosis and treatment guidance.

The role of microRNAs in acute lymphoblastic leukaemia: From biology to applications

MicroRNAs (miRNAs) that are characterized by small, noncoding RNA have an essential role in the pathogenesis of human diseases, including cancer. Furthermore, miRNAs, as a new paradigm of epigenetic regulators, play an important role in normal development and cellular function. This literature review summarizes the recurrent mechanism of gene regulation through miRNAs and, consequently, the impact of regulated genes on different cellular processes, including proliferation, metastasis, prognosis, and apoptosis. Additionally, what is important to note is that the expression of miRNAs in various cancer cells is different, and miRNAs have various target genes in various cancers. Accordingly, a proper understanding of gene regulation by miRNAs contributes to new perspectives in miRNA-based therapeutic strategies. SIGNIFICANCE OF THE STUDY: MiRNAs are considered as a crucial regulator of gene expression. The genes also play an important role in the expression of miRNAs; as a result, there is a relationship between them. In recent years, targeted therapy with miRNAs has been a significant challenge. Studying the mechanisms through which miRNAs regulate various cancer cell processes, including apoptosis, proliferation, and metastasis, is very critical in the treatment of cancer through miRNAs. Definitely, a proper understanding of the impacts of aberrant expression of miRNAs on cancer cell processes leads to new therapeutic strategies in the targeted therapy with miRNAs.

The Potential Markers of Circulating microRNAs and long non-coding RNAs in Alzheimer's Disease

Alzheimer’s disease (AD) is a neurodegenerative disorder and one of the leading causes of disability and mortality in the late life with no curative treatment currently. Thus, it is urgently to establish sensitive and non-invasive biomarkers for AD diagnosis, particularly in the early stage. Recently, emerging number of microRNAs (miRNAs) and long-noncoding RNAs (lncRNAs) are considered as effective biomarkers in various diseases as they possess characteristics of stable, resistant to RNAase digestion and many extreme conditions in circulatory fluid. This review highlights recent advances in the identification of the aberrantly expressed miRNAs and lncRNAs in circulatory network for detection of AD. We summarized the abnormal expressed miRNAs in blood and cerebrospinal fluid (CSF), and detailed discussed the functions and molecular mechanism of serum or plasma miRNAs-miR-195, miR-155, miR-34a, miR-9, miR-206, miR-125b and miR-29 in the regulation of AD progression. In addition, we also elaborated the role of circulating lncRNA major including beta-site APP cleaving enzyme 1 (BACE1) and its antisense lncRNA BACE1-AS in AD pathological advancement. In brief, confirming the aberrantly expressed circulating miRNAs and lncRNAs will provide an effective testing tools for treatment of AD in the future.

MicroRNAs Dysregulation and Metabolism in Multiple System Atrophy

Multiple system atrophy (MSA) is an adult onset, fatal disease, characterized by an accumulation of alpha-synuclein (α-syn) in oligodendroglial cells. MicroRNAs (miRNAs) are small non-coding RNAs involved in post-translational regulation and several biological processes. Disruption of miRNA-related pathways in the central nervous system (CNS) plays an important role in the pathogenesis of neurodegenerative diseases, including MSA. While the exact mechanisms underlying miRNAs in the pathogenesis of MSA remain unclear, it is known that miRNAs can repress the translation of messenger RNAs (mRNAs) that regulate the following pathogenesis associated with MSA: autophagy, neuroinflammation, α-syn accumulation, synaptic transmission, oxidative stress, and apoptosis. In this review, the metabolism of miRNAs and their functional roles in the pathogenesis of MSA are discussed, thereby highlighting miRNAs as potential new biomarkers for the diagnosis of MSA and in increasing our understanding of the disease process.

Long non-coding RNA LINC00152 promotes tumorigenesis via sponging miR-193b-3p in osteosarcoma

The majority of the human genome has been revealed to be non-protein-coding, which are transcribed into noncoding RNAs (ncRNA), RNAs which are not translated into protein. Long non-coding RNAs (lncRNAs), including LINC00152, may be associated with the pathogenesis of different types of cancer. LINC00152 serves as an endogenous sponge by binding to micro-RNAs (miRNAs) and inhibiting their activity. The current study revealed that LINC00152 is overexpressed in osteosarcoma cells, leading to increased cell proliferation, and decreased G0/G1 cell cycle arrest and apoptosis. The binding of miR-193b-3p to LINC00152 was demonstrated by dual-luciferase assay, and led to miR-193b-3p downregulation in osteosarcoma cells. Knockdown of LINC00152 revealed an antitumorigenic effect by reducing cell proliferation and increasing G0/G1 arrest and apoptosis. Inhibiting miR-193b-3p reversed the effects of LINC00152 knockdown. These results suggested that LINC00152 binds to miR-193b-3p and reduces its expression level, leading to increased cell proliferation and decreased G0/G1 cell cycle arrest and apoptosis in osteosarcoma cells.

The Emerging Role of microRNAs in Polyglutamine Diseases

MicroRNAs (miRNAs) are small non-coding molecules that regulate a large amount of post-transcriptional repressor genes by recognizing semi-complementary target sequences that are normally located in the 3' UTR of the mRNA. Altered expression of miRNA has been related to several pathological processes, including polyglutamine (Poly Q) diseases. Specific expression patterns in the circulating fluids and brain parenchyma have been speculated as potential biomarkers for Poly Q disease diagnosis and prognosis. Several miRNAs have been consistently identified in diseases including Huntington's disease (HD) and spinocerebellar ataxia (SCA). In our review, we describe the emerging role of miRNAs in Poly Q diseases and provide an overview on general miRNA biology, implications in pathophysiology, and their potential roles as future biomarkers and applications for therapy.

miRNAs Identify Shared Pathways in Alzheimer's and Parkinson's Diseases

Despite the identification of several dozens of common genetic variants associated with Alzheimer's disease (AD) and Parkinson's disease (PD), most of the genetic risk remains uncharacterised. Therefore, it is important to understand the role of regulatory elements, such as miRNAs. Dysregulated miRNAs are implicated in AD and PD, with potential value in dissecting the shared pathophysiology between the two disorders. miRNAs relevant to both neurodegenerative diseases are related to axonal guidance, apoptosis, and inflammation, therefore, AD and PD likely arise from similar underlying biological pathway defects. Furthermore, pathways regulated by APP, L1CAM, and genes of the caspase family may represent promising therapeutic miRNA targets in AD and PD since they are targeted by dysregulated miRNAs in both disorders.

miR-9-5p modulates the progression of Parkinson's disease by targeting SIRT1

Parkinson's disease (PD) is a most common progressive neurodegenerative disease mainly occurring in the elderly. Plenty of miRNAs are reported to involve in the progression of PD. However, the role of miR-9-5p in the regulation of PD pathogenesis remains unclear. The expressions of miR-9-5p and Sirtuin 1 (SIRT1) at mRNA and protein levels were determined by qRT-PCR and western blotting (WB) analyses. Cell viability and apoptosis were evaluated by MTT and flow cytometry. The levels of apoptosis-related proteins Bcl-2, Bax, Caspase-3 were detected by WB analysis. The releases of inflammatory cytokines IL-1β and TNF-α were examined by ELISA assay. ROS generation, LDH and SOD activity were evaluated using commercially available kits. Bioinformatics analysis, luciferase reporter, and qRT-PCR assays were performed to demonstrate the true interaction between miR-9-5p and SIRT1. Results showed miR-9-5p was upregulated and SIRT1 was downregulated in MPP⁺-treated SH-SY5Y cells in dose- and time- dependent manners. miR-9-5p knockdown attenuated MPP⁺-induced neurotoxicity in SH-SY5Y cells, as evidenced by the enhancement in cell viability, and the suppression in cell apoptosis, inflammation, and oxidative stress. SIRT1 was identified to be a target of miR-9-5p. Restoration of miR-9-5p aggravated SIRT1-attenuated neurotoxicity in MPP⁺-treated SH-SY5Y cells. Our data suggested these data indicated that miR-9-5p exerted a neurotoxic role in MPP⁺-derived PD by directly targeting STAT1, providing a potential therapeutic strategy for patients troubled by PD.