Convergence of miRNA expression profiling, α-synuclein interacton and GWAS in Parkinson's disease

Integrative Metabolome and Proteome Analysis of Cerebrospinal Fluid in Parkinson's Disease

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra. Recent studies have highlighted the significant role of cerebrospinal fluid (CSF) in reflecting pathophysiological PD brain conditions by analyzing the components of CSF. Based on the published literature, we created a single network with altered metabolites in the CSF of patients with PD. We analyzed biological functions related to the transmembrane of mitochondria, respiration of mitochondria, neurodegeneration, and PD using a bioinformatics tool. As the proteome reflects phenotypes, we collected proteome data based on published papers, and the biological function of the single network showed similarities with that of the metabolomic network. Then, we analyzed the single network of integrated metabolome and proteome. In silico predictions based on the single network with integrated metabolomics and proteomics showed that neurodegeneration and PD were predicted to be activated. In contrast, mitochondrial transmembrane activity and respiration were predicted to be suppressed in the CSF of patients with PD. This review underscores the importance of integrated omics analyses in deciphering PD's complex biochemical networks underlying neurodegeneration.

Cohort-specific boolean models highlight different regulatory modules during Parkinson's disease progression

Parkinson's disease (PD) involves complex molecular interactions and diverse comorbidities. To better understand its molecular mechanisms, we employed systems medicine approaches using the PD map, a detailed repository of PD-related interactions and applied Probabilistic Boolean Networks (PBNs) to capture the stochastic nature of molecular dynamics. By integrating cohort-level and real-world patient data, we modeled PD's subtype-specific pathway deregulations, providing a refined representation of its molecular landscape. Our study identifies key regulatory biomolecules and pathways that vary across PD subtypes, offering insights into the disease's progression and patient stratification. These findings have significant implications for the development of targeted therapeutic interventions.

Regulatory miR-SNP rs4636297A > G in miR-126 is linked to increased risk of rigidity feature in patients with Parkinson's disease

INTRODUCTION

A growing body of strong evidence shows that the dysfunction of miRNAs plays key roles in the development and progression of Parkinson's disease (PD), however, little data has been reported on the association of their SNPs with PD susceptibility. In this study, we investigated the association of regulatory miR-SNP rs4636297A > G with a functional effect on the expression of miRNA-126, as a key dysregulated miRNA in the PD, with the susceptibility and clinical features of the PD.

METHODS AND MATERIALS

In current study, we included a population consisting of 120 patients with PD and 120 clinically healthy individuals, and their blood samples were taken. After extracting the DNAs, the genotyping of the miR-SNP rs4636297A > G was done through RFLP-PCR technique. Finally, the association of this SNP with the risk and clinical features of PD was determined.

RESULTS

Although the results showed that the two groups did not differ significantly in terms of allelic and genotype frequencies, it was clinically found that individuals with genotypes carrying the minor allele G (AG and GG genotypes) of the miR-SNP rs4636297A > G had an increased risk of developing rigidity feature in the PD compared to its homozygous major AA genotype (GG genotype; OR = 5.14, p = 0.038 & GA genotype; OR = 4.32, p = 0.032).

CONCLUSION

We report for the first time a significant association of functional regulatory SNP rs4636297A > G in the miR-126 with the Parkinson's clinicopathology. Therefore, this miR-SNP can have a potential predictive biomarker capacity for rigidity in PD, although this hypothesis needs further investigation in the future.

miR-142-3p alleviates neuronal apoptosis in Parkinson's disease via negatively regulating C9orf72

Although microRNA (miRNA) have important clinical prospects in the early diagnosis and treatment of PD, the functions and mechanisms of miRNAs in PD models remain poorly defined. In this study, we screened 9 miRNAs that differently expressed in PD patients and found that miR-142-3p expression was downregulated in both animal and cell models of PD. We showed that overexpression of miR-142-3p significantly alleviates the neuronal damage induced by MPP+, while knockdown of miR-142-3p exacerbates the neuronal damage caused by MPP+. We further found that miR-142-3p targets and inhibits the expression of C9orf72. Knockdown of C9orf72 mitigated neuronal autophagy dysfunction by reducing excessive activation of the AKT/mTOR pathway after MPP+ stimulation, thereby exerted neuroprotective effects. This study reveals that miR-142-3p protects neuron in PD pathogenesis via negatively regulating C9orf72 and enhancing autophagy. Our findings provides an insight into the development of potential biomarkers and therapeutic targets for PD.

Nuclear alpha-synuclein accelerates cell senescence and neurodegeneration

BACKGROUND

The progression of Parkinson's disease (PD) is related to ageing. The accumulation of nuclear alpha-synuclein (α-syn) may accelerate the occurrence of neurodegenerative diseases, but its role in PD remains poorly understood.

METHODS

In the present study, α-syn expression was specifically targeted to the nucleus by constructing an adeno-associated virus (AAV) vector in which a nuclear localization sequence (NLS) was added to the α-syn coding sequence. Virus-mediated gene transfer, behavioural tests, RNA-Seq, immunohistochemistry, western blotting, and quantitative real-time PCR were then performed.

RESULTS

In vivo experiments using a mouse model showed that nuclear α-syn increased the severity of the PD-like phenotype, including the loss of dopaminergic neurons concomitant with motor impairment and the formation of α-syn inclusions. These nuclear inclusions contained α-syn species of high molecular weights and induced strong transcriptional dysregulation, especially induced high expression of p21 and senescence-associated secretory phenotype (SASP)-related genes. In addition, the transcriptional alterations induced by nuclear α-syn were associated with gliosis, inflammation, oxidative and DNA damage, and lysosomal dysfunction, and they eventually accelerated neuronal loss and neurodegeneration.

CONCLUSIONS

Our results suggest that nuclear α-syn plays a crucial role in PD pathogenesis.

An Overview of Epigenetic Changes in the Parkinson's Disease Brain

Parkinson's disease is a progressive neurodegenerative disorder, predominantly of the motor system. Although some genetic components and cellular mechanisms of Parkinson's have been identified, much is still unknown. In recent years, emerging evidence has indicated that non-DNA-sequence variation (in particular epigenetic mechanisms) is likely to play a crucial role in the development and progression of the disease. Here, we present an up-to-date overview of epigenetic processes including DNA methylation, DNA hydroxymethylation, histone modifications and non-coding RNAs implicated in the brain of those with Parkinson's disease. We will also discuss the limitations of current epigenetic research in Parkinson's disease, the advantages of simultaneously studying genetics and epigenetics, and putative novel epigenetic therapies.

Unveiling the regulatory of miR-101-3p on ZNF746 in a Parkinson's disease cell model: Implications for therapeutic targeting

In this study, we explored the regulatory role of microRNA miR-101-3p on the zinc finger protein 746 (ZNF746), also known as PARIS, which is implicated in both sporadic and familial forms of Parkinson's disease. In a Parkinson's disease cell model, utilizing SH-SY5Y cells treated with 1-methyl-4-phenylpyridine (MPP+), we observed that miR-101-3p was downregulated, while ZNF746 was upregulated. To investigate the direct impact of miR-101-3p on ZNF746, our team conducted overexpression experiments, successfully reversing ZNF746's expression at both the mRNA and protein levels, as confirmed through quantitative PCR and western blotting. We also performed luciferase assays, providing compelling evidence that ZNF746 is a direct target of miR-101-3p. Additionally, we noted that miR-101-3p overexpression resulted in increased expression of PGC1α, a gene targeted by ZNF746. Functionally, we assessed the implications of miR-101-3p overexpression through MTS assays and flow cytometry, revealing significant promotion of cell viability, inhibition of ROS production, and reduced apoptosis in the Parkinson's disease cell model. In conclusion, this study highlights the role of miR-101-3p in regulating ZNF746 expression and suggests its potential as a therapeutic target for Parkinson's disease. These findings provide valuable molecular insights that could pave the way for innovative treatment strategies in combating this debilitating neurodegenerative disorder.

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.

Small RNA-big impact: exosomal miRNAs in mitochondrial dysfunction in various diseases

Mitochondria are multitasking organelles involved in maintaining the cell homoeostasis. Beyond its well-established role in cellular bioenergetics, mitochondria also function as signal organelles to propagate various cellular outcomes. However, mitochondria have a self-destructive arsenal of factors driving the development of diseases caused by mitochondrial dysfunction. Extracellular vesicles (EVs), a heterogeneous group of membranous nano-sized vesicles, are present in a variety of bodily fluids. EVs serve as mediators for intercellular interaction. Exosomes are a class of small EVs (30-100 nm) released by most cells. Exosomes carry various cargo including microRNAs (miRNAs), a class of short noncoding RNAs. Recent studies have closely associated exosomal miRNAs with various human diseases, including diseases caused by mitochondrial dysfunction, which are a group of complex multifactorial diseases and have not been comprehensively described. In this review, we first briefly introduce the characteristics of EVs. Then, we focus on possible mechanisms regarding exosome-mitochondria interaction through integrating signalling networks. Moreover, we summarize recent advances in the knowledge of the role of exosomal miRNAs in various diseases, describing how mitochondria are changed in disease status. Finally, we propose future research directions to provide a novel therapeutic strategy that could slow the disease progress mediated by mitochondrial dysfunction.

Unraveling the role of miRNAs in the diagnosis, progression, and therapeutic intervention of Parkinson's disease

Parkinson's disease (PD) is a debilitating neurological disorder characterized by the impairment of the motor system, resulting in symptoms such as resting tremor, cogwheel rigidity, bradykinesia, difficulty with gait, and postural instability. The occurrence of striatal dopamine insufficiency can be attributed to a notable decline in dopaminergic neurons inside the substantia nigra pars compacta. Additionally, the development of Lewy bodies serves as a pathological hallmark of PD. While current therapy approaches for PD aim to preserve dopaminergic neurons or replenish dopamine levels in the brain, it is important to acknowledge that achieving complete remission of the condition remains elusive. MicroRNAs (miRNAs, miR) are a class of small, non-coding ribonucleic acids involved in regulating gene expression at the post-transcriptional level. The miRNAs play a crucial part in the underlying pathogenic mechanisms of several neurodegenerative illnesses, including PD. The aim of this review is to explore the role of miRNAs in regulating genes associated with the onset and progression of PD, investigate the potential of miRNAs as a diagnostic tool, assess the effectiveness of targeting specific miRNAs as an alternative therapeutic strategy to impede disease advancement, and discuss the utilization of newly developed nanoparticles for delivering miRNAs as neurodegenerative therapies.

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.

Orchestration of a blood-derived and ADARB1-centred network in Alzheimer's and Parkinson's disease

The peripheral immune system is thought to influence the pathogenesis of the central nervous system in Alzheimer's disease (AD) and Parkinson's disease (PD). This study aimed to investigate the characteristics of peripheral leukocytes in AD and PD by comprehensively analyzing the transcriptomic and metabolic features in the blood (NCONTROL = 15; NAD = 11; NPD = 13). The study found an ADARB1-centered module that was associated with diagnosis, phenethylamine, and glutamate. The module consisted of ADARB1, a vital RNA-editing enzyme, LINC02960, and 109 miRNAs. The study also predicted that the ADARB1 and involved regulators were targeted by miRNAs in the ADARB1 module. The integrated analysis of transcriptome and metabolic panel revealed a central role of ADARB1, miR-199b-5p, miR-26a, miR-450b-5p, miR-34c-5p, glutamate and phenethylamine in the regulatory relationships. The study highlights a set of synergetic non-coding RNA related to ADARB1 in the blood ecosystem of AD and PD with dynamic glutamate and phenethylamine, providing new insights into the pathogenesis of these diseases.

MicroRNAs in Parkinson's disease: a systematic review and diagnostic accuracy meta-analysis

Current clinical tests for Parkinson's disease (PD) provide insufficient diagnostic accuracy leading to an urgent need for improved diagnostic biomarkers. As microRNAs (miRNAs) are promising biomarkers of various diseases, including PD, this systematic review and meta-analysis aimed to assess the diagnostic accuracy of biofluid miRNAs in PD. All studies reporting data on miRNAs expression in PD patients compared to controls were included. Gene targets and significant pathways associated with miRNAs expressed in more than 3 biofluid studies with the same direction of change were analyzed using target prediction and enrichment analysis. A bivariate model was used to calculate sensitivity, specificity, likelihood ratios, and diagnostic odds ratio. While miR-24-3p and miR-214-3p were the most reported miRNA (7 each), miR-331-5p was found to be consistently up regulated in 4 different biofluids. Importantly, miR-19b-3p, miR-24-3p, miR-146a-5p, and miR-221-3p were reported in multiple studies without conflicting directions of change in serum and bioinformatic analysis found the targets of these miRNAs to be associated with pathways important in PD pathology. Of the 102 studies from the systematic review, 15 studies reported sensitivity and specificity data on combinations of miRNAs and were pooled for meta-analysis. Studies (17) reporting sensitivity and specificity data on single microRNA were pooled in a separate meta-analysis. Meta-analysis of the combinations of miRNAs (15 studies) showed that biofluid miRNAs can discriminate between PD patients and controls with good diagnostic accuracy (sensitivity = 0.82, 95% CI 0.76-0.87; specificity = 0.80, 95% CI 0.74-0.84; AUC = 0.87, 95% CI 0.83-0.89). However, we found multiple studies included more males with PD than any other group therefore possibly introducing a sex-related selection bias. Overall, our study captures key miRNAs which may represent a point of focus for future studies and the development of diagnostic panels whilst also highlighting the importance of appropriate study design to develop representative biomarker panels for the diagnosis of PD.

microRNA and circRNA in Parkinson's Disease and atypical parkinsonian syndromes

Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP) are atypical parkinsonian syndromes (APS) with various clinical phenotypes and considerable clinical overlap with idiopathic Parkinson's disease (iPD). This disease heterogeneity makes ante-mortem diagnosis extremely challenging with up to 24% of patients misdiagnosed. Because diagnosis is predominantly clinical, there is great interest in identifying biomarkers for early diagnosis and differentiation of the different types of parkinsonism. Compared to protein biomarkers, microRNAs (miRNAs) and circularRNAs (circRNAs) are stable tissue-specific molecules that can be accurately measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). This chapter critically reviews miRNAs and circRNAs as diagnostic biomarkers and therapeutics to differentiate atypical parkinsonian disorders and their role in disease pathogenesis.

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.

MicroRNA super-resolution imaging in blood for Alzheimer's disease

We propose a novel blood biomarker detection method that uses miRNA super-resolution imaging to enable the early diagnosis of Alzheimer's disease (AD). Here, we report a singlemolecule detection method for visualizing disease-specific miRNA in tissue from an AD mice model, and peripheral blood mononuclear cells (PBMCs) from AD patients. Using optimized Magnified Analysis of Proteome (MAPs), we confirmed that five miRNAs contribute to neurodegenerative disease in the brain hippocampi of 5XFAD and wild-type mice. We also assessed PBMCs isolated from the whole blood of AD patients and a healthy control group, and subsequently analyzed those samples using miRNA super-resolution imaging. We detected more miR-200a-3p expression in the cornu ammonis 1 and dentate gyrus regions of 3 month-old 5XFAD mice than in wild-type mice. Additionally, miRNA super-resolution imaging of blood provides AD diagnosis platform for studying miRNA regulation inside cells at the single molecule level. Our results present a potential liquid biopsy method that could improve the diagnosis of early stage AD and other diseases. [BMB Reports 2023; 56(3): 190-195].

Differential serum microRNAs in premotor LRRK2 G2019S carriers from Parkinson's disease

The LRRK2 G2019S pathogenic mutation causes LRRK2-associated Parkinson's disease (L2PD) with incomplete penetrance. LRRK2 non-manifesting carriers (L2NMC) are at PD high risk but predicting pheno-conversion is challenging given the lack of progression biomarkers. To investigate novel biomarkers for PD premotor stages, we performed a longitudinal microRNA (miRNA) assessment of serum samples from G2019S L2NMC followed-up over 8 years. Our cohort consisted of G2019S L2NMC stratified by dopamine transporter single-photon emission computed tomography (DaT-SPECT) into DaT-negative (n = 20) and DaT-positive L2NMC (n = 20), pheno-converted G2019S L2PD patients (n = 20), idiopathic PD (iPD) (n = 19), and controls (n = 40). We also screened a second cohort of L2PD patients (n = 19) and controls (n = 20) (Total n = 158). Compared to healthy controls, we identified eight deregulated miRNAs in DaT-negative L2NMC, six in DaT-positive L2NMC, and one in L2PD. Between groups, the highest miRNA differences, 24 candidate miRNAs, occurred between DaT-positive L2NMC and L2PD. Longitudinally, we found 11 common miRNAs with sustained variation in DaT-negative and DaT-positive L2NMCs compared to their baselines. Our study identifies novel miRNA alterations in premotor stages of PD co-occurring with progressive DaT-SPECT decline before motor manifestation, whose deregulation seems to attenuate after the diagnosis of L2PD. Moreover, we identified four miRNAs with relatively high discriminative ability (AUC = 0.82) between non-pheno-converted DaT-positive G2019S carriers and pheno-converted L2PD patients (miR-4505, miR-8069, miR-6125, and miR-451a), which hold potential as early progression biomarkers for 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.

Emerging Role of MicroRNA-30c in Neurological Disorders

MicroRNAs (miRNAs or miRs) are a class of small non-coding RNAs that negatively regulate the expression of target genes by interacting with 3' untranslated regions of target mRNAs to induce mRNA degradation and translational repression. The miR-30 family members are involved in the development of many tissues and organs and participate in the pathogenesis of human diseases. As a key member of the miR-30 family, miR-30c has been implicated in neurological disorders such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and stroke. Mechanistically, miR-30c may act as a multi-functional regulator of different pathogenic processes such as autophagy, apoptosis, endoplasmic reticulum stress, inflammation, oxidative stress, thrombosis, and neurovascular function, thereby contributing to different disease states. Here, we review and discuss the biogenesis, gene regulation, and the role and mechanisms of action of miR-30c in several neurological disorders and therapeutic potential in clinics.

MicroRNA Expression Profile Changes in the Leukocytes of Parkinson’s Disease Patients

Parkinson’s disease (PD) is one of the most common movement disorders. It is primarily diagnosed clinically. A correct diagnosis of PD in its early stages is important for the development of a pathogenic treatment, which necessitates a search for potential biomarkers of the disease. We evaluated the diagnostic value of several microRNAs and their relationship with the clinical characteristics of PD. The study included 70 PD patients and 40 healthy volunteers. We analyzed the expression of 15 microRNAs in blood leukocytes, which were selected based on literature data and modern concepts of molecular PD pathogenesis. All patients were evaluated using the Hoehn and Yahr scale, UPDRS, NMSQ, and PDQ-39. The data analysis revealed a statistically significant increase in the expression of miR-7-5p, miR-29c-3p, and miR-185-5p and a statistically significant decrease in the expression of miR-29a-3p and miR-30c-1-5p in leukocytes in PD. However, the altered microRNA profile was shown to have a moderate diagnostic value for PD diagnosis. MicroRNA expression changes were associated with the motor and non-motor phenotypic features of PD and administration of anti-Parkinson’s drugs. Also, a relationship between some of the microRNAs studied and the duration and severity of PD was found, which may potentially be used to monitor disease progression.

Serum MicroRNAs Predict Isolated Rapid Eye Movement Sleep Behavior Disorder and Lewy Body Diseases

BACKGROUND

Isolated rapid eye movement sleep behavior disorder (IRBD) is a well-established clinical risk factor for Lewy body diseases (LBDs), such as Parkinson's disease (PD) and dementia with Lewy bodies (DLB).

OBJECTIVE

To elucidate whether serum microRNA (miRNA) deregulation in IRBD can antedate the diagnosis of LBD by performing a longitudinal study in different progression stages of IRBD before and after LBD diagnosis and assessing the predictive performance of differentially expressed miRNAs by machine learning-based modeling.

METHODS

Using genome-wide miRNA analysis and real-time quantitative polymerase chain reaction validation, we assessed serum miRNA profiles from patients with IRBD stratified by dopamine transporter (DaT) single-photon emission computed tomography into DaT-negative IRBD (n = 17) and DaT-positive IRBD (n = 21), IRBD phenoconverted into LBD (n = 13), and controls (n = 20). Longitudinally, we followed up the IRBD cohort by studying three time point serum samples over 26 months.

RESULTS

We found sustained cross-sectional and longitudinal deregulation of 12 miRNAs across the RBD continuum, including DaT-negative IRBD, DaT-positive IRBD, and LBD phenoconverted IRBD (let-7c-5p, miR-19b-3p, miR-140, miR-22-3p, miR-221-3p, miR-24-3p, miR-25-3p, miR-29c-3p, miR-361-5p, miR-425-5p, miR-4505, and miR-451a) (false discovery rate P < 0.05). Age- and sex-adjusted predictive modeling based on the 12 differentially expressed miRNA biosignatures discriminated IRBD and PD or DLB from controls with an area under the curve of 98% (95% confidence interval: 89-99%).

CONCLUSIONS

Besides clinical diagnosis of IRBD or imaging markers such as DaT single-photon emission computed tomography, specific miRNA biosignatures alone hold promise as progression biomarkers for patients with IRBD for predicting PD and DLB clinical outcomes. Further miRNA studies in other PD at-risk populations, such as LRRK2 mutation asymptomatic carriers or hyposmic subjects, are warranted. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

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.

DNA methylation as a mediator of genetic and environmental influences on Parkinson's disease susceptibility: Impacts of alpha-Synuclein, physical activity, and pesticide exposure on the epigenome

Parkinson's disease (PD) is a neurodegenerative disorder with a complex etiology and increasing prevalence worldwide. As PD is influenced by a combination of genetic and environment/lifestyle factors in approximately 90% of cases, there is increasing interest in identification of the interindividual mechanisms underlying the development of PD as well as actionable lifestyle factors that can influence risk. This narrative review presents an outline of the genetic and environmental factors contributing to PD risk and explores the possible roles of cytosine methylation and hydroxymethylation in the etiology and/or as early-stage biomarkers of PD, with an emphasis on epigenome-wide association studies (EWAS) of PD conducted over the past decade. Specifically, we focused on variants in the SNCA gene, exposure to pesticides, and physical activity as key contributors to PD risk. Current research indicates that these factors individually impact the epigenome, particularly at the level of CpG methylation. There is also emerging evidence for interaction effects between genetic and environmental contributions to PD risk, possibly acting across multiple omics layers. We speculated that this may be one reason for the poor replicability of the results of EWAS for PD reported to date. Our goal is to provide direction for future epigenetics studies of PD to build upon existing foundations and leverage large datasets, new technologies, and relevant statistical approaches to further elucidate the etiology of this disease.

Functional Assessment of Stroke-Induced Regulation of miR-20a-3p and Its Role as a Neuroprotectant

MicroRNAs have gained popularity as a potential treatment for many diseases, including stroke. This study identifies and characterizes a specific member of the miR-17-92 cluster, miR-20a-3p, as a possible stroke therapeutic. A comprehensive microRNA screening showed that miR-20a-3p was significantly upregulated in astrocytes of adult female rats, which typically have better stroke outcomes, while it was profoundly downregulated in astrocytes of middle-aged females and adult and middle-aged males, groups that typically have more severe stroke outcomes. Assays using primary human astrocytes and neurons show that miR-20a-3p treatment alters mitochondrial dynamics in both cell types. To assess whether stroke outcomes could be improved by elevating astrocytic miR-20a-3p, we created a tetracycline (Tet)-induced recombinant adeno-associated virus (rAAV) construct where miR-20a-3p was located downstream a glial fibrillary acidic protein promoter. Treatment with doxycycline induced miR-20-3p expression in astrocytes, reducing mortality and modestly improving sensory motor behavior. A second Tet-induced rAAV construct was created in which miR-20a-3p was located downstream of a neuron-specific enolase (NSE) promoter. These experiments demonstrate that neuronal expression of miR-20a-3p is vastly more neuroprotective than astrocytic expression, with animals receiving the miR-20a-3p vector showing reduced infarction and sensory motor improvement. Intravenous injections, which are a therapeutically tractable treatment route, with miR-20a-3p mimic 4 h after middle cerebral artery occlusion (MCAo) significantly improved stroke outcomes including infarct volume and sensory motor performance. Improvement was not observed when miR-20a-3p was given immediately or 24 h after MCAo, identifying a unique delayed therapeutic window. Overall, this study identifies a novel neuroprotective microRNA and characterizes several key pathways by which it can improve stroke outcomes.

Alpha-Synuclein Aggregation Pathway in Parkinson's Disease: Current Status and Novel Therapeutic Approaches

Following Alzheimer’s, Parkinson’s disease (PD) is the second-most common neurodegenerative disorder, sharing an unclear pathophysiology, a multifactorial profile, and massive social costs worldwide. Despite this, no disease-modifying therapy is available. PD is tightly associated with α-synuclein (α-Syn) deposits, which become organised into insoluble, amyloid fibrils. As a typical intrinsically disordered protein, α-Syn adopts a monomeric, random coil conformation in an aqueous solution, while its interaction with lipid membranes drives the transition of the molecule part into an α-helical structure. The central unstructured region of α-Syn is involved in fibril formation by converting to well-defined, β-sheet rich secondary structures. Presently, most therapeutic strategies against PD are focused on designing small molecules, peptides, and peptidomimetics that can directly target α-Syn and its aggregation pathway. Other approaches include gene silencing, cell transplantation, stimulation of intracellular clearance with autophagy promoters, and degradation pathways based on immunotherapy of amyloid fibrils. In the present review, we sum marise the current advances related to α-Syn aggregation/neurotoxicity. These findings present a valuable arsenal for the further development of efficient, nontoxic, and non-invasive therapeutic protocols for disease-modifying therapy that tackles disease onset and progression in the future.

Dysregulated miRNAs as Biomarkers and Therapeutical Targets in Neurodegenerative Diseases

Alzheimer’s disease (AD), Parkinson’s disease (PD), and Amyotrophic Lateral Sclerosis (ALS) are representative neurodegenerative diseases (NDs) characterized by degeneration of selective neurons, as well as the lack of effective biomarkers and therapeutic treatments. In the last decade, microRNAs (miRNAs) have gained considerable interest in diagnostics and therapy of NDs, owing to their aberrant expression and their ability to target multiple molecules and pathways. Here, we provide an overview of dysregulated miRNAs in fluids (blood or cerebrospinal fluid) and nervous tissue of AD, PD, and ALS patients. By emphasizing those that are commonly dysregulated in these NDs, we highlight their potential role as biomarkers or therapeutical targets and describe the use of antisense oligonucleotides as miRNA therapies.

Hippocampal miR-124 Participates in the Pathogenesis of Depression via Regulating the Expression of BDNF in a Chronic Social Defeat Stress Model of Depression

OBJECTIVE

As one of the most prevalent psychiatric disorders, the exact pathogenesis of depression remains elusive. Therefore, there is an urgent need to identify novel antidepressants for effective treatment. MicroRNA-124 (miR-124), the most abundant miRNA in brain tissue, plays a key effect on adult neurogenesis and neuronal differentiation. However, the mechanism of miR-124 in depression has not been clarified so far. The aim of this study is to provide broad insight into the mechanisms underlying depression.

METHODS

In the study, we used the forced swim test (FST), the tail suspension test (TST), and a Chronic Social Defeat Stress (CSDS) mice model of depression. Quantitative real-time reverse transcription PCR (qRT-PCR), western blotting, immunofluorescence and virus-mediated gene transfer were used together. The level of plasma corticosterone in mice was analyzed by Enzyme Linked Immunosorbent Assay (ELISA).

RESULTS

It was found that CSDS robustly increased the level of miR-124 in the hippocampus. Genetic knockdown of hippocampal miR-124 produced significant antidepressant-like effects in the CSDS model of depression. Furthermore, AAV-siR-124-EGFP treatment increased the level of plasma corticosterone in CSDS-induced mice. Moreover, it was found that the antidepressant-like effects induced by miR-124 inhibition required the hippocampal BDNF-TrkB system.

CONCLUSION

Hippocampal miR-124 participated in the pathogenesis of depression by regulating BDNF biosynthesis and was a feasible antidepressant target.

Deubiquitinating enzymes (DUBs): decipher underlying basis of neurodegenerative diseases

Neurodegenerative diseases (NDs) are characterized by the aggregation of neurotoxic proteins in the central nervous system. Aberrant protein accumulation in NDs is largely caused by the dysfunction of the two principal protein catabolism pathways, the ubiquitin-proteasome system (UPS), and the autophagy-lysosomal pathway (ALP). The two protein quality control pathways are bridged by ubiquitination, a post-translational modification that can induce protein degradation via both the UPS and the ALP. Perturbed ubiquitination leads to the formation of toxic aggregates and inclusion bodies that are deleterious to neurons. Ubiquitination is promoted by a cascade of ubiquitinating enzymes and counter-regulated by deubiquitinating enzymes (DUBs). As fine-tuning regulators of ubiquitination and protein degradation, DUBs modulate the stability of ND-associated pathogenic proteins including amyloid β protein, Tau, and α-synuclein. Besides, DUBs also influence ND-associated mitophagy, protein secretion, and neuroinflammation. Given the various and critical functions of DUBs in NDs, DUBs may become potential therapeutic targets for NDs.

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.

Roles of Non-Coding RNAs as Novel Diagnostic Biomarkers in Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder, affecting 5%of the elderly population. Currently, the diagnosis of PD is mainly based on clinical features and no definitive diagnostic biomarkers have been identified. The discovery of biomarkers at the earliest stages of PD is of extreme interest. This review focuses on the current findings in the field of circulating non-coding RNAs in PD. We briefly describe the more established circulating biomarkers in PD and provide a more thorough review of non-coding RNAs, in particular microRNAs, long non-coding RNAs and circular RNAs, differentially expressed in PD, highlighting their potential for being considered as biomarkers for diagnosis. Together, these studies hold promise for the use of peripheral biomarkers for the diagnosis of PD.

The role of noncoding RNAs in Parkinson's disease: biomarkers and associations with pathogenic pathways

The discovery of various noncoding RNAs (ncRNAs) and their biological implications is a growing area in cell biology. Increasing evidence has revealed canonical and noncanonical functions of long and small ncRNAs, including microRNAs, long ncRNAs (lncRNAs), circular RNAs, PIWI-interacting RNAs, and tRNA-derived fragments. These ncRNAs have the ability to regulate gene expression and modify metabolic pathways. Thus, they may have important roles as diagnostic biomarkers or therapeutic targets in various diseases, including neurodegenerative disorders, especially Parkinson's disease. Recently, through diverse sequencing technologies and a wide variety of bioinformatic analytical tools, such as reverse transcriptase quantitative PCR, microarrays, next-generation sequencing and long-read sequencing, numerous ncRNAs have been shown to be associated with neurodegenerative disorders, including Parkinson's disease. In this review article, we will first introduce the biogenesis of different ncRNAs, including microRNAs, PIWI-interacting RNAs, circular RNAs, long noncoding RNAs, and tRNA-derived fragments. The pros and cons of the detection platforms of ncRNAs and the reproducibility of bioinformatic analytical tools will be discussed in the second part. Finally, the recent discovery of numerous PD-associated ncRNAs and their association with the diagnosis and pathophysiology of PD are reviewed, and microRNAs and long ncRNAs that are transported by exosomes in biofluids are particularly emphasized.

Non-coding RNAs and their bioengineering applications for neurological diseases

Engineering of cellular biomolecules is an emerging landscape presenting creative therapeutic opportunities. Recently, several strategies such as biomimetic materials, drug-releasing scaffolds, stem cells, and dynamic culture systems have been developed to improve specific biological functions, however, have been confounded with fundamental and technical roadblocks. Rapidly emerging investigations on the bioengineering prospects of mammalian ribonucleic acid (RNA) is expected to result in significant biomedical advances. More specifically, the current trend focuses on devising non-coding (nc) RNAs as therapeutic candidates for complex neurological diseases. Given the pleiotropic and regulatory role, ncRNAs such as microRNAs and long non-coding RNAs are deemed as attractive therapeutic candidates. Currently, the list of non-coding RNAs in mammals is evolving, which presents the plethora of hidden possibilities including their scope in biomedicine. Herein, we critically review on the emerging repertoire of ncRNAs in neurological diseases such as Alzheimer’s disease, Parkinson’s disease, neuroinflammation and drug abuse disorders. Importantly, we present the advances in engineering of ncRNAs to improve their biocompatibility and therapeutic feasibility as well as provide key insights into the applications of bioengineered non-coding RNAs that are investigated for neurological diseases.

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.

A Review of miRNAs as Biomarkers and Effect of Dietary Modulation in Obesity Associated Cognitive Decline and Neurodegenerative Disorders

There has been a progressive increase in the prevalence of obesity and its comorbidities such as type 2 diabetes and cardiovascular diseases worldwide. Recent studies have suggested that the crosstalk between adipose tissue and central nervous system (CNS), through cellular mediators and signaling pathways, may causally link obesity with cognitive decline and give rise to neurodegenerative disorders. Several mechanisms have been proposed in obesity, including inflammation, oxidative stress, insulin resistance, altered lipid and cholesterol homeostasis, which may result in neuroinflammation, altered brain insulin signaling, amyloid-beta (Aβ) deposition and neuronal cell death. Since obesity is associated with functional and morphological alterations in the adipose tissues, the resulting peripheral immune response augments the development and progression of cognitive decline and increases susceptibility of neurodegenerative disorders, such as Alzheimer's Disease (AD) and Parkinson's Disease (PD). Studies have also elucidated an important role of high fat diet in the exacerbation of these clinical conditions. However, the underlying factors that propel and sustain this obesity associated cognitive decline and neurodegeneration, remains highly elusive. Moreover, the mechanisms linking these phenomena are not well-understood. The cumulative line of evidence have demonstrated an important role of microRNAs (miRNAs), a class of small non-coding RNAs that regulate gene expression and transcriptional changes, as biomarkers of pathophysiological conditions. Despite the lack of utility in current clinical practices, miRNAs have been shown to be highly specific and sensitive to the clinical condition being studied. Based on these observations, this review aims to assess the role of several miRNAs and aim to elucidate underlying mechanisms that link obesity with cognitive decline and neurodegenerative disorders. Furthermore, this review will also provide evidence for the effect of dietary modulation which can potentially ameliorate cognitive decline and neurodegenerative diseases associated with obesity.

MiRNA-199a-5p targets WNT2 to regulate depression through the CREB/BDNF signaling in hippocampal neuron

INTRODUCTION

This study mainly investigated the role of miR-199a-5p in depression.

METHODS

qRT-PCR and western blotting were employed to detect the expressions of miR-199a-5p, CREB and BDNF. Sucrose preference test, forced swimming test, and tail suspension test were performed to evaluate depression-related symptoms. MTT assays and flow cytometry were used to examine the cell reproduction and apoptotic cells of hippocampal neuron.

RESULTS

The data demonstrated that the expression levels of miR-199a-5p in the cerebrospinal fluids and serums of depression patient and the hippocampus of chronic unpredictable mild stress (CUMS) mouse were significantly increased. However, the expressions of WNT2, p-CREB, and BDNF were inhibited. In addition, miR-199a-5p-inhibitor enhanced sucrose preferences of CUMS mouse and decreased immobile time in sucrose preference test and forced swimming test. Knockdown of WNT2 attenuated the effects of miR-199a-5p-inhibitor on cell reproduction and apoptotic cells of hippocampal neuron and the expression of WNT2, p-CREB, and BDNF.

CONCLUSION

MiR-199a-5p can target WNT2 to enhance the development of depression through regulation of the CREB/BDNF signaling.

TRIAL REGISTRATION

JNU-Hos-49284.

Plasma hsa-mir-19b is a potential LevoDopa therapy marker

Parkinson's disease (PD) is the second most common neurodegenerative disorder among the elderly, the diagnostic and prognostic of which is based mostly on clinical signs. LevoDopa replacement is the gold standard therapy for PD, as it ameliorates the motor symptoms. However, it does not affect the progression of the disease and its long‐term use triggers severe complications. There are no bona fide biomarkers for monitoring the patients’ response to LevoDopa and predicting the efficacy of levodopa treatment. Here, we have combined qPCR microRNA array screening with analysis of validated miRs in naïve versus Levodopa‐treated PD patients. We have identified plasma miR‐19b as a possible biomarker for LevoDopa therapy and validated this result in human differentiated dopaminergic neurons exposed to LevoDopa. In silico analysis suggests that the LevoDopa‐induced miR‐19b regulates ubiquitin‐mediated proteolysis.

Expression levels of specific microRNAs are increased after exercise and are associated with cognitive improvement in Parkinson's disease

There is a consensus regarding the efficacy of physical exercise in maintaining or improving human health; however, there are few studies examining the effect of physical exercise on the expression levels of microRNAs (miRNA/miRs) in Parkinson's disease (PD). The aim of the present study was to investigate the effects of an interval training program on a cycle ergometer on the expression levels of miR‑106a‑5p, miR‑103a‑3p and miR‑29a‑3p in serum samples from men with PD. This was a quasi‑experimental study with pre‑ and post‑testing and with a non‑equivalent group design. The participants were selected based on the eligibility criteria and subsequently classified into two groups: Experimental group and control group. The evaluations were performed at the beginning of the study (week 0) and after 8 weeks of the intervention program (week 9). The interval training program was performed on a cycle ergometer for 30 min, three times a week during an 8‑week period. The expression levels of miR‑106a‑5p, miR‑103a‑3p and miR‑29a‑3p in the experimental group were increased after physical exercise and were associated with cognitive improvement in men with PD. However, further studies are required to clarify the potential use of these circulating miRNAs as markers of adaptation to physical exercise. Collectively, the present results indicated that these three miRNAs may be associated with the exercise response and cognitive improvement in men with PD.

miR-335 Targets LRRK2 and Mitigates Inflammation in Parkinson's Disease

Parkinson’s disease (PD) is mainly driven by dopaminergic neuronal degeneration in the substantia nigra pars compacta accompanied by chronic neuroinflammation. Despite being mainly sporadic, approximately 10% of all cases are defined as heritable forms of PD, with mutations in the leucine-rich repeat kinase (LRRK2) gene being the most frequent known cause of familial PD. MicroRNAs (miRNAs or miRs), including miR-335, are frequently deregulated in neurodegenerative diseases, such as PD. Here, we aimed to dissect the protective role of miR-335 during inflammation and/or neurodegenerative events in experimental models of PD. Our results showed that miR-335 is significantly downregulated in different PD-mimicking conditions, including BV2 microglia cells stimulated with lipopolysaccharide (LPS) and/or overexpressing wild-type LRRK2. Importantly, these results were confirmed in serum of mice injected with 1-methyl-1-4-phenyl-1,2,3,6-tetrahydripyridine hydrochloride (MPTP), and further validated in patients with idiopathic PD (iPD) and those harboring mutations in LRRK2 (LRRK2-PD), thus corroborating potential clinical relevance. Mechanistically, miR-335 directly targeted LRRK2 mRNA. In the BV2 and N9 microglia cell lines, miR-335 strongly counteracted LPS-induced proinflammatory gene expression, and downregulated receptor interacting protein 1 (RIP1) and RIP3, two important players of necroptotic and inflammatory signaling pathways. Further, miR-335 inhibited LPS-mediated ERK1/2 activation. LRRK2-Wt-induced proinflammatory gene expression was also significantly reduced by miR-335 overexpression. Finally, in SH-SY5Y neuroblastoma cells, miR-335 decreased the expression of pro-inflammatory genes triggered by α-synuclein. In conclusion, we revealed novel roles for miR-335 in both microglia and neuronal cells that strongly halt the effects of classical inflammatory stimuli or LRRK2-Wt overexpression, thus attenuating chronic neuroinflammation.

Global mRNA and miRNA Analysis Reveal Key Processes in the Initial Response to Infection with WSSV in the Pacific Whiteleg Shrimp

White Spot Disease (WSD) presents a major barrier to penaeid shrimp production. Mechanisms underlying White Spot Syndrome Virus (WSSV) susceptibility in penaeids are poorly understood due to limited information related to early infection. We investigated mRNA and miRNA transcription in Penaeus vannamei over 36 h following infection. Over this time course, 6192 transcripts and 27 miRNAs were differentially expressed—with limited differential expression from 3–12 h post injection (hpi) and a more significant transcriptional response associated with the onset of disease symptoms (24 hpi). During early infection, regulated processes included cytoskeletal remodelling and alterations in phagocytic activity that may assist WSSV entry and translocation, novel miRNA-induced metabolic shifts, and the downregulation of ATP-dependent proton transporter subunits that may impair cellular recycling. During later infection, uncoupling of the electron transport chain may drive cellular dysfunction and lead to high mortalities in infected penaeids. We propose that post-transcriptional silencing of the immune priming gene Dscam (downregulated following infections) by a novel shrimp miRNA (Pva-pmiR-78; upregulated) as a potential mechanism preventing future recognition of WSSV that may be suppressed in surviving shrimp. Our findings improve our understanding of WSD pathogenesis in P. vannamei and provide potential avenues for future development of prophylactics and treatments.

Oxytocin Alleviates MPTP-Induced Neurotoxicity in Mice by Targeting MicroRNA-26a/Death-Associated Protein Kinase 1 Pathway

Neurotoxicity is one of the major pathological changes in multiple neurological disorders, including Alzheimer's disease (AD) and Parkinson's disease (PD), the second popular neurodegenerative disease in aged people. It is known that the AD and PD share the similar neuropathological hallmarks, such as the oxidative stress, loss of specific neurons, and aggregation of specific proteins. However, there are no effective therapeutic drugs for both AD and PD yet. Oxytocin (OXT) is a small peptide with 9 amino acids that is neuroprotective to many neurological disorders. Whether OXT administration confers neuroprotection to 1-methyl-4-phenyl-1, 2, 3, 6- tetrahydropyridine (MPTP)-induced neurotoxicity in mice are still not known. In this study, we first found that the OXT levels are decreased in MPTP mice. Supplementation with OXT effectively rescues the locomotor disabilities and anxiety-like behaviors in MPTP mice. OXT also alleviates the hyperphosphorylation of α-synuclein at S129 site and the loss of dopaminergic neurons in the substantia nigra pars compacta, as well as the oxidative stress in the MPTP mice, and alleviates both oxidative stress and cell cytotoxicity in vitro. Furthermore, we found that OXT could inhibit the miR-26a/DAPK1 signal pathway in MPTP mice. In summary, our study demonstrates protective effects of OXT in MPTP mice and that miR-26a/DAPK1 signaling pathway may play an important role in mediating the protection of OXT.

Deep sequencing of sncRNAs reveals hallmarks and regulatory modules of the transcriptome during Parkinson’s disease progression

Noncoding RNAs have diagnostic and prognostic importance in Parkinson's disease (PD). We studied circulating small noncoding RNAs (sncRNAs) in two large-scale longitudinal PD cohorts (Parkinson's Progression Markers Initiative (PPMI) and Luxembourg Parkinson's Study (NCER-PD)) and modeled their impact on the transcriptome. Sequencing of sncRNAs in 5,450 blood samples of 1,614 individuals in PPMI yielded 323 billion reads, most of which mapped to microRNAs but covered also other RNA classes such as piwi-interacting RNAs, ribosomal RNAs and small nucleolar RNAs. Dysregulated microRNAs associated with disease and disease progression occur in two distinct waves in the third and seventh decade of life. Originating predominantly from immune cells, they resemble a systemic inflammation response and mitochondrial dysfunction, two hallmarks of PD. Profiling 1,553 samples from 1,024 individuals in the NCER-PD cohort validated biomarkers and main findings by an independent technology. Finally, network analysis of sncRNA and transcriptome sequencing from PPMI identified regulatory modules emerging in patients with progressing PD.

Comprehensive miRNome-Wide Profiling in a Neuronal Cell Model of Synucleinopathy Implies Involvement of Cell Cycle Genes

Growing evidence suggests that epigenetic mechanisms like microRNA-mediated transcriptional regulation contribute to the pathogenesis of parkinsonism. In order to study the influence of microRNAs (miRNAs), we analyzed the miRNome 2 days prior to major cell death in α-synuclein-overexpressing Lund human mesencephalic neurons, a well-established cell model of Parkinson’s disease (PD), by next-generation sequencing. The expression levels of 23 miRNAs were significantly altered in α-synuclein-overexpressing cells, 11 were down- and 12 upregulated (P < 0.01; non-adjusted). The in silico analysis of known target genes of these miRNAs was complemented by the inclusion of a transcriptome dataset (BeadChip) of the same cellular system, revealing the G0/G1 cell cycle transition to be markedly enriched. Out of 124 KEGG-annotated cell cycle genes, 15 were present in the miRNA target gene dataset and six G0/G1 cell cycle genes were found to be significantly altered upon α-synuclein overexpression, with five genes up- (CCND1, CCND2, and CDK4 at P < 0.01; E2F3, MYC at P < 0.05) and one gene downregulated (CDKN1C at P < 0.001). Additionally, several of these altered genes are targeted by miRNAs hsa-miR-34a-5p and hsa-miR-34c-5p, which also modulate α-synuclein expression levels. Functional intervention by siRNA-mediated knockdown of the cell cycle gene cyclin D1 (CCND1) confirmed that silencing of cell cycle initiation is able to substantially reduce α-synuclein-mediated cytotoxicity. The present findings suggest that α-synuclein accumulation induces microRNA-mediated aberrant cell cycle activation in post-mitotic dopaminergic neurons. Thus, the mitotic cell cycle pathway at the level of miRNAs might offer interesting novel therapeutic targets for PD.

Data Integration Reveals the Potential Biomarkers of Circulating MicroRNAs in Osteoarthritis

The abnormal expression of circulating miRNAs (c-miRNAs) has become an emerging field in the development of miRNAs-based diagnostic and therapeutic tools for human diseases, including osteoarthritis (OA). OA is the most common form of arthritis leading to disability and a major socioeconomic burden. The abnormal expression of miRNAs plays important roles in the pathogenesis of OA. Unraveling the role of miRNAs in the pathogenesis of OA will throw light on the potential for the development of miRNAs-based diagnostic and therapeutic tools for OA. This article reviews and highlights recent advances in the study of miRNAs in OA, with specific demonstration of the functions of miRNA, especially c-miRNA, in OA pathogenesis as well as its potential implication in the treatment of OA. Based on a systematic literature search using online databases, we figured out the following main points: (1) the integrative systematic review of c-mRNAs and its target genes related to OA pathogenesis; (2) the potential use of c-miRNAs for OA diagnosis purposes as potential biomarkers; and (3) for therapeutic purposes, and we also highlight certain remedies that regulate microRNA expression based on its target genes.

An Introspective Approach: A Lifetime of Parkinson's Disease Research and Not Much to Show for it Yet?

I feel part of a massive effort to understand what is wrong with motor systems in the brain relating to Parkinson’s disease. Today, the symptoms of the disease can be modified slightly, but dopamine neurons still die; the disease progression continues inexorably. Maybe the next research phase will bring the power of modern genetics to bear on halting, or better, preventing cell death. The arrival of accessible human neuron assemblies in organoids perhaps will provide a better access to the processes underlying neuronal demise.

microRNA signatures in prodromal REM sleep behavior disorder and early Parkinson's disease as noninvasive biomarkers

The flow of gene expression or "The central dogma of molecular biology": DNA - RNA - protein, proposed by Watson & Crick sixty years ago, is a tightly controlled cell process. In the middle of this journey, the mRNA molecule is regulated by "RNA interference" (RNAi), a posttranscriptional gene silencing mechanism. A microRNA is an endogenous short double-stranded RNA that down-regulates hundreds of mRNAs by RNAi, maintaining healthy cell physiology. In contrast, aberrant expressions of microRNAs play a role in Parkinson's disease (PD) pathogenesis. The damage may start at an early period of brain degeneration, in the non-motor or "prodromal" stage, where autonomic, mood and sleep changes are often manifested. REM-sleep behavior disorder (RBD) is the prodromal manifestation with the highest odds for conversion into PD, thereby a valuable phenotype for disease prediction. The present review focuses on microRNAs' role in the pathogenesis of PD and RBD, summarizing the state-of-the-art of these RNA molecules as noninvasive biomarkers for non-motor prodromal (RBD) and early PD.

Cytokine and Gene Expression Profiling in Patients with HFE-Associated Hereditary Hemochromatosis according to Genetic Profile

BACKGROUND

Hemochromatosis gene (HFE)-associated hereditary hemochromatosis (HH) is characterized by downregulation of hepcidin synthesis, leading to increased intestinal iron absorption.

OBJECTIVES

The objectives were to characterize and elucidate a possible association between gene expression profile, hepcidin levels, disease severity, and markers of inflammation in HFE-associated HH patients.

METHODS

Thirty-nine HFE-associated HH patients were recruited and assigned to 2 groups according to genetic profile: C282Y homozygotes in 1 group and patients with H63D, as homozygote or in combination with C282Y, in the other group. Eleven healthy first-time blood donors were recruited as controls. Gene expression was characterized from peripheral blood cells, and inflammatory cytokines and hepcidin-25 isoform were quantified in serum. Biochemical disease characteristics were recorded.

RESULTS

Elevated levels of interleukin 8 were observed in a significant higher proportion of patients than controls. In addition, compared to controls, gene expression of ζ-globin was significantly increased among C282Y homozygote patients, while gene expression of matrix metalloproteinase 8, and other neutrophil-secreted proteins, was significantly upregulated in patients with H63D.

CONCLUSION

Different disease signatures may characterize HH patients according to their HFE genetic profile. Studies on larger populations, including analyses at protein level, are necessary to confirm these findings.

Statistical methods with exhaustive search in the identification of gene-gene interactions for colorectal cancer

Though additive forms of heritability are primarily studied in genetics, nonlinear, non-additive gene-gene interactions, that is, epistasis, could explain a portion of the missing heritability in complex human diseases including cancer. In recent years, powerful computational methods have been introduced to understand multivariable genetic factors of these complex human diseases in extremely high-dimensional genome-wide data. In this study, we investigated the performance of three powerful methods, BOolean Operation-based Screening and Testing (BOOST), FastEpistasis, and Tree-based Epistasis Association Mapping (TEAM) to identify interacting genetic risk factors of colorectal cancer (CRC) for genome-wide association studies (GWAS). After quality-control based data preprocessing, we applied these three algorithms to a CRC GWAS data set, and selected the top-ranked 100 single-nucleotide polymorphism (SNP) pairs identified by each method (251 SNPs in total), among which 74 pairs were common between FastEpistasis and BOOST. The identified SNPs by BOOST, FastEpistasis, and TEAM mapped to 58, 57, and 62 genes, respectively. Some genes highlighted by our study, including MACF1, USP49, SMAD2, SMAD3, TGFBR1, and RHOA, have been detected in previous CRC-related research. We also identified some new genes with potential biological relevance to CRC such as CCDC32. Furthermore, we constructed the network of these top SNP pairs for three methods, and the patterns identified in the networks show that some SNPs including rs2412531, rs349699, and rs17142011 play a crucial role in the classification of disease status in our study.

Parkinson's disease and pesticides: Are microRNAs the missing link?

Parkinson's disease (PD) is a common neurodegenerative disorder that leads to significant morbidity and decline in the quality of life. It develops due to loss of dopaminergic neurons in the substantia nigra pars compacta, and among its pathogenic factors oxidative stress plays a critical role in disease progression. Pesticides are a broad class of chemicals widely used in agriculture and households for the protection of crops from insects and fungi. Several of them have been incriminated as risk factors for PD, but the underlying mechanisms have yet to be fully understood. MicroRNAs (miRNAs) are small, non-coding RNA molecules that play an important role in regulating mRNA translation and protein synthesis. miRNA levels have been shown to be affected in several diseases as well. Since the studies on the association between pesticides and PD have yet to reach definitive conclusions, here we review recent evidence on deregulated microRNAs upon pesticide exposure, and attempt to find an overlap between miRNAs deregulated in PD and pesticides, as a missing link between the two, and enhance future research in this direction.