Long non-coding RNA-p21 regulates MPP+-induced neuronal injury by targeting miR-625 and derepressing TRPM2 in SH-SY5Y cells

Non-coding RNAs in Parkinson's disease: Regulating SNCA and alpha-synuclein aggregation

Parkinson's disease is one of the vital neurodegenerative ailments attributed to a rise in Alpha-synuclein proteins leading to the advancement of motor and cognitive deterioration. Interestingly, in PD lncRNAs, miRNAs and siRNAs are also key regulators of SNCA and alpha-synuclein aggregation. This review will focus on the roles of these three types of small RNAs in trebling the development of PD through regulating SNCA expression or alpha-synuclein protein mediating the RNA from acting. Parkinson's disease is defined by the build-up of alpha-synuclein protein resulting predominantly from the elevated expression level of the SNCA gene. Non-coding RNAs have gained broad appeal as fundamental modulators of gene expression and protein aggregation dynamics, with significant implications on the aetiology of PD. LncRNAs modulate SNCA transcription and edit epigenetic modifications, while miRNA target mRNA is involved in the stability and translation of count alpha-synuclein. Considering all these data, siRNAs can achieve the precise gene silencing effect that directly induces the downregulation of SNCA mRNA. This review also summarizes some recent reports about the interaction between these ncRNAs with the SNCA gene and alpha-synuclein protein, each through its independent in addition to synergistic mechanisms. This review highlights the possibility of therapeutic interventions to perturb SNCA expression to prevent alpha-synuclein aggregation via targeting ncRNAs that might be spun off novel drug development for PD.

Hsa_circ_0054220 Upregulates HMGA1 by the Competitive RNA Pattern to Promote Neural Impairment in MPTP Model of Parkinson's Disease

Parkinson's disease (PD) is a common neurodegenerative disease. Circular RNAs (circRNAs) have been confirmed to regulate neurodegenerative diseases. This study was aimed to explore hsa_circ_0054220 functions in PD. MPP-stimulated SH-SY5Y cells were established as the PD cell model. PD mouse model was established by MPTP. Gene expression in cells and tissues was tested by RT-qPCR. Cell viability and apoptosis were evaluated through CCK-8 and TUNEL assays. The interactions of RNAs were determined by RNA pull-down assay, RIP assay, and luciferase reporter assay. Circ_0054220 expressed at a high level in MPP-treated SH-SY5Y cells. Circ_0054220 inhibition promoted viability and suppressed apoptosis in MPP-stimulated cells. Furthermore, we found that circ_0054220 can competitively bind to miR-145 and miR-625 to upregulate high mobility group A1 (HMGA1) expression. HMGA1 was positively regulated by circ_0054220 and overexpressed in MPP-treated cells as well as the striatum (STR), substantia nigra pars compacta (SNpc), and serum of MPTP-induced mouse model of PD. HMGA1 overexpression counteracted the function of circ_0054220 silencing on cell apoptosis. Furthermore, HMGA1 inhibition notably alleviated motor dysfunction and increased the quantity of neurons in mice resembling PD. Circ_0054220 upregulates HMGA1 by the competitive endogenous RNAs (ceRNA) pattern to promote neural impairment in PD.

Non-Coding RNAs and Neurodegenerative Diseases: Information of their Roles in Apoptosis

Apoptosis can be known as a key factor in the pathogenesis of neurodegenerative disorders. In disease conditions, the rate of apoptosis expands and tissue damage may become apparent. Recently, the scientific studies of the non-coding RNAs (ncRNAs) has provided new information of the molecular mechanisms that contribute to neurodegenerative disorders. Numerous reports have documented that ncRNAs have important contributions to several biological processes associated with the increase of neurodegenerative disorders. In addition, microRNAs (miRNAs), circular RNAs (circRNAs), as well as, long ncRNAs (lncRNAs) represent ncRNAs subtypes with the usual dysregulation in neurodegenerative disorders. Dysregulating ncRNAs has been associated with inhibiting or stimulating apoptosis in neurodegenerative disorders. Therefore, this review highlighted several ncRNAs linked to apoptosis in neurodegenerative disorders. CircRNAs, lncRNAs, and miRNAs were also illustrated completely regarding the respective signaling pathways of apoptosis.

The mechanistic view of non-coding RNAs as a regulator of inflammatory pathogenesis of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta, leading to motor and non-motor symptoms. Emerging evidence suggests that inflammation plays a crucial role in the pathogenesis of PD, with the NLRP3 inflammasome implicated as a key mediator. Nfon-coding RNAs (ncRNAs), including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), have recently garnered attention for their regulatory roles in various biological processes, including inflammation. This review aims to provide a mechanistic insight into how ncRNAs function as regulators of inflammatory pathways in PD, with a specific focus on the NLRP3 inflammasome. We discuss the dysregulation of miRNAs and lncRNAs in PD pathogenesis and their impact on neuroinflammation through modulation of NLRP3 activation, cytokine production, and microglial activation. Additionally, we explore the crosstalk between ncRNAs, alpha-synuclein pathology, and mitochondrial dysfunction, further elucidating the intricate network underlying PD-associated inflammation. Understanding the mechanistic roles of ncRNAs in regulating inflammatory pathways may offer novel therapeutic targets for the treatment of PD and provide insights into the broader implications of ncRNA-mediated regulation in neuroinflammatory diseases.

Potential of oligonucleotide- and protein/peptide-based therapeutics in the management of toxicant/stressor-induced diseases

Exposure to toxicants/stressors has been linked to the development of many human diseases. They could affect various cellular components, such as DNA, proteins, lipids, and non-coding RNAs (ncRNA), thereby triggering various cellular pathways, particularly oxidative stress, inflammatory responses, and apoptosis, which can contribute to pathophysiological states. Accordingly, modulation of these pathways has been the focus of numerous investigations for managing related diseases. The involvement of various ncRNAs, such as small interfering RNA (siRNA), microRNAs (miRNA), and long non-coding RNAs (lncRNA), as well as various proteins and peptides in mediating these pathways, provides many target sites for pharmaceutical intervention. In this regard, various oligonucleotide- and protein/peptide-based therapies have been developed to treat toxicity-induced diseases, which have shown promising results in vitro and in vivo. This comprehensive review provides information about various aspects of toxicity-related diseases including their causing factors, main underlying mechanisms and intermediates, and their roles in pathophysiological states. Particularly, it highlights the principles and mechanisms of oligonucleotide- and protein/peptide-based therapies in the treatment of toxicity-related diseases. Furthermore, various issues of oligonucleotides and proteins/peptides for clinical usage and potential solutions are discussed.

Neuronal dysfunction and gene modulation by non-coding RNA in Parkinson's disease and synucleinopathies

Over the last few decades, emerging evidence suggests that non-coding RNAs (ncRNAs) including long-non-coding RNA (lncRNA), microRNA (miRNA) and circular-RNA (circRNA) contribute to the molecular events underlying progressive neuronal degeneration, and a plethora of ncRNAs have been identified significantly misregulated in many neurodegenerative diseases, including Parkinson's disease and synucleinopathy. Although a direct link between neuropathology and causative candidates has not been clearly established in many cases, the contribution of ncRNAs to the molecular processes leading to cellular dysfunction observed in neurodegenerative diseases has been addressed, suggesting that they may play a role in the pathophysiology of these diseases. Aim of the present Review is to overview and discuss recent literature focused on the role of RNA-based mechanisms involved in different aspects of neuronal pathology in Parkinson's disease and synucleinopathy models.

Role of non-coding RNAs in neuroblastoma

Neuroblastoma is known as the most prevalent extracranial malignancy in childhood with a neural crest origin. It has been widely accepted that non-coding RNAs (ncRNAs) play important roles in many types of cancer, including glioma and gastrointestinal cancers. They may regulate the cancer gene network. According to recent sequencing and profiling studies, ncRNAs genes are deregulated in human cancers via deletion, amplification, abnormal epigenetic, or transcriptional regulation. Disturbances in the expression of ncRNAs may act either as oncogenes or as anti-tumor suppressor genes, and can lead to the induction of cancer hallmarks. ncRNAs can be secreted from tumor cells inside exosomes, where they can be transferred to other cells to affect their function. However, these topics still need more study to clarify their exact roles, so the present review addresses different roles and functions of ncRNAs in neuroblastoma.

Synucleinopathies: Intrinsic and Extrinsic Factors

α-Synucleinopathies are a group of neurodegenerative disorders characterized by alterations in α-synuclein (α-syn), a protein associated with membrane phospholipids, whose precise function in normal cells is still unknown. These kinds of diseases are caused by multiple factors, but the regulation of the α-syn gene is believed to play a central role in the pathology of these disorders; therefore, the α-syn gene is one of the most studied genes. α-Synucleinopathies are complex disorders that derive from the interaction between genetic and environmental factors. Here, we offer an update on the landscape of the epigenetic regulation of α-syn gene expression that has been linked with α-synucleinopathies. We also delve into the reciprocal influence between epigenetic modifications and other factors related to these disorders, such as posttranslational modifications, microbiota participation, interactions with lipids, neuroinflammation and oxidative stress, to promote α-syn aggregation by acting on the transcription and/or translation of the α-syn gene.

Non-coding RNAs as key players in the neurodegenerative diseases: Multi-platform strategies and approaches for exploring the Genome's dark matter

A growing amount of evidence in the last few years has begun to unravel that non-coding RNAs have a myriad of functions in gene regulation. Intensive investigation on non-coding RNAs (ncRNAs) has led to exploring their broad role in neurodegenerative diseases (NDs) owing to their regulatory role in gene expression. RNA sequencing technologies and transcriptome analysis has unveiled significant dysregulation of ncRNAs attributed to their biogenesis, upregulation, downregulation, aberrant epigenetic regulation, and abnormal transcription. Despite these advances, the understanding of their potential as therapeutic targets and biomarkers underpinning detailed mechanisms is still unknown. Advancements in bioinformatics and molecular technologies have improved our knowledge of the dark matter of the genome in terms of recognition and functional validation. This review aims to shed light on ncRNAs biogenesis, function, and potential role in NDs. Further deepening of their role is provided through a focus on the most recent platforms, experimental approaches, and computational analysis to investigate ncRNAs. Furthermore, this review summarizes and evaluates well-studied miRNAs, lncRNAs and circRNAs concerning their potential role in pathogenesis and use as biomarkers in NDs. Finally, a perspective on the main challenges and novel methods for the future and broad therapeutic use of ncRNAs is offered.

Competing endogenous RNA (ceRNA) networks in Parkinson's disease: A systematic review

Parkinson's disease (PD) is a distinctive clinical syndrome with several causes and clinical manifestations. Aside from an infectious cause, PD is a rapidly developing neurological disorder with a global rise in frequency. Notably, improved knowledge of molecular pathways and the developing novel diagnostic methods may result in better therapy for PD patients. In this regard, the amount of research on ceRNA axes is rising, highlighting the importance of these axes in PD. CeRNAs are transcripts that cross-regulate one another via competition for shared microRNAs (miRNAs). These transcripts may be either coding RNAs (mRNAs) or non-coding RNAs (ncRNAs). This research used a systematic review to assess validated loops of ceRNA in PD. The Prisma guideline was used to conduct this systematic review, which entailed systematically examining the articles of seven databases. Out of 309 entries, forty articles met all criteria for inclusion and were summarized in the appropriate table. CeRNA axes have been described through one of the shared vital components of the axes, including lncRNAs such as NEAT1, SNHG family, HOTAIR, MALAT1, XIST, circRNAs, and lincRNAs. Understanding the multiple aspects of this regulatory structure may aid in elucidating the unknown causal causes of PD and providing innovative molecular therapeutic targets and medical fields.

Valproic Acid Attenuated PTZ-induced Oxidative Stress, Inflammation, and Apoptosis in the SH-SY5Y Cells via Modulating the TRPM2 Channel

Valproic acid (VPA) is one of the most widely used antiepileptic drugs. The protective role of VPA and the role of the TRPM2 channel in this mechanism in developing neuronal damage due to increased pentylenetetrazol (PTZ)-induced neurotoxicity in SH-SY5Y cells were not clarified. Here, we investigated the role of VPA via modulation of TRPM2 channel on cell death and oxidative neurotoxicity in SH-SY5Y cells. The SH-SY5Y cell toxicity model was constructed by treating SH-SY5Y cells with PTZ. The VPA and TRPM2 channel antagonist N-(p-amylcinnamoyl) anthranilic acid (ACA) were added to prevent neurotoxicity in PTZ-induced SH-SY5Y cells. The role of the VPA and TRPM2 channel was evaluated using an ELISA kit and patch-clamp. Primarily, antioxidant (GSH and GSH-Px) and oxidative stress (MDA and ROS) levels and inflammatory factors (IL-1β, IL-6, and TNF-α) in cells were determined by ELISA kits. Then, TRPM2 channel activation in cells was detected using both the ELISA kit and patch-clamp methods. In addition, apoptosis and cell viability levels in cells were determined by performing PARP1, caspase-3, caspase-9, and CCK-8 assays by ELISA kits. Our results showed that the TRPM2 channel is vital in damage formation in PTZ-induced cells. Furthermore, we observed that VPA attenuated PTZ-induced neurotoxicity by suppressing cells' oxidative stress and inflammation, and reducing TRPM2 channel activation. In our study, in which the protective effect of VPA and the role of the TRPM2 channel in PTZ-induced SH-SY5Y cells were investigated for the first time, we can conclude that VPA treatment and TRPM2 channel blockade can suppress PTZ-induced neurotoxicity.

Long-noncoding RNAs as epigenetic regulators in neurodegenerative diseases

The growing and rapid development of high-throughput sequencing technologies have allowed a greater understanding of the mechanisms underlying gene expression regulation. Editing the epigenome and epitranscriptome directs the fate of the transcript influencing the functional outcome of each mRNA. In this context, non-coding RNAs play a decisive role in addressing the expression regulation at the gene and chromosomal levels. Long-noncoding RNAs, consisting of more than 200 nucleotides, have been shown to act as epigenetic regulators in several key molecular processes involving neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and Huntington's disease. Long-noncoding RNAs are abundantly expressed in the central nervous system, suggesting that their deregulation could trigger neuronal degeneration through RNA modifications. The evaluation of their diagnostic significance and therapeutic potential could lead to new treatments for these diseases for which there is no cure.

Significant Role of Long Non-coding RNAs in Parkinson's Disease

BACKGROUND

Parkinson's disease (PD) is the second most common neurodegenerative disease in the world, with clinical manifestations of resting tremor, akinesia (or bradykinesia), rigidity, and postural instability. However, the molecular pathogenesis of PD is still unclear, and its effective treatments are limited. Substantial evidence demonstrates that long non-coding RNAs (lncRNAs) have important functions in various human diseases, such as cancer, cardiovascular disease, and neurodegenerative diseases. Therefore, the main purpose of this study is to review the role of lncRNAs in the pathogenesis of PD.

METHODS

The role of lncRNAs in the pathogenesis of PD is summarized by reviewing Pubmed.

RESULTS

Thirty different lncRNAs are aberrantly expressed in PD and promote or inhibit PD by mediating ubiquitin-proteasome system, autophagy-lysosomal pathway, dopamine (DA) neuronal apoptosis, mitochondrial function, oxidative stress, and neuroinflammation.

CONCLUSION

In this direction, lncRNA may contribute to the treatment of PD as a diagnostic and therapeutic target for PD.

Non-coding RNAs: The Neuroinflammatory Regulators in Neurodegenerative Diseases

As a common indication of nervous system diseases, neuroinflammation has attracted more and more attention, especially in the process of a variety of neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Two types of non-coding RNAs (ncRNAs) are widely involved in the process of neuroinflammation in neurodegenerative diseases, namely long non-coding RNAs (lncRNAs) and microRNAs (miRNAs). However, no research has systematically summarized that lncRNAs and miRNAs regulate neurodegenerative diseases through neuroinflammatory mechanisms. In this study, we summarize four main mechanisms of lncRNAs and miRNAs involved in neuroinflammation in neurodegenerative diseases, including the imbalance between proinflammatory and neuroprotective cells in microglia and astrocytes, NLRP3 inflammasome, oxidative stress, and mitochondrial dysfunction, and inflammatory mediators. We hope to clarify the regulatory mechanism of lncRNAs and miRNAs in neurodegenerative diseases and provide new insights into the etiological treatment of neurodegenerative diseases from the perspective of neuroinflammation.

Crosstalk between regulatory non-coding RNAs and oxidative stress in Parkinson’s disease

Parkinson’s disease is the second most common neurodegenerative disease after Alzheimer’s disease, which imposes an ever-increasing burden on society. Many studies have indicated that oxidative stress may play an important role in Parkinson’s disease through multiple processes related to dysfunction or loss of neurons. Besides, several subtypes of non-coding RNAs are found to be involved in this neurodegenerative disorder. However, the interplay between oxidative stress and regulatory non-coding RNAs in Parkinson’s disease remains to be clarified. In this article, we comprehensively survey and overview the role of regulatory ncRNAs in combination with oxidative stress in Parkinson’s disease. The interaction between them is also summarized. We aim to provide readers with a relatively novel insight into the pathogenesis of Parkinson’s disease, which would contribute to the development of pre-clinical diagnosis and treatment.

Long Intergenic Noncoding RNAs Affect Biological Pathways Underlying Autoimmune and Neurodegenerative Disorders

Long intergenic noncoding RNAs (lincRNAs) are a class of independently transcribed molecules longer than 200 nucleotides that do not overlap known protein-coding genes. LincRNAs have diverse roles in gene expression and participate in a spectrum of biological processes. Dysregulation of lincRNA expression can abrogate cellular homeostasis, cell differentiation, and development and can also deregulate the immune and nervous systems. A growing body of literature indicates their important and multifaceted roles in the pathogenesis of several different diseases. Furthermore, certain lincRNAs can be considered potential therapeutic targets and valuable diagnostic or prognostic biomarkers capable of predicting the onset of a disease, its degree of activity, or the progression phase. In this review, we discuss possible mechanisms and molecular functions of lincRNAs in the pathogenesis of selected autoimmune and neurodegenerative disorders: multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, Sjögren’s syndrome, Huntington’s disease, Parkinson’s disease, Alzheimer’s disease, and amyotrophic lateral sclerosis. This summary can provide new ideas for future research, diagnosis, and treatment of these highly prevalent and devastating diseases.

The Role of Non-Coding RNAs in the Pathogenesis of Parkinson’s Disease: Recent Advancement

Parkinson’s disease (PD) is a prevalent neurodegenerative aging disorder that manifests as motor and non-motor symptoms, and its etiopathogenesis is influenced by non-coding RNAs (ncRNAs). Signal pathway and gene sequence studies have proposed that alteration of ncRNAs is relevant to the occurrence and development of PD. Furthermore, many studies on brain tissues and body fluids from patients with PD indicate that variations in ncRNAs and their target genes could trigger or exacerbate neurodegenerative pathogenesis and serve as potential non-invasive biomarkers of PD. Numerous ncRNAs have been considered regulators of apoptosis, α-syn misfolding and aggregation, mitochondrial dysfunction, autophagy, and neuroinflammation in PD etiology, and evidence is mounting for the determination of the role of competing endogenous RNA (ceRNA) mechanisms in disease development. In this review, we discuss the current knowledge regarding the regulation and function of ncRNAs as well as ceRNA networks in PD pathogenesis, focusing on microRNAs, long ncRNAs, and circular RNAs to increase the understanding of the disease and propose potential target identification and treatment in the early stages of PD.

Regulation of Oxidative Stress by Long Non-coding RNAs in Central Nervous System Disorders

Central nervous system (CNS) disorders, such as ischemic stroke, Alzheimer’s disease, Parkinson’s disease, spinal cord injury, glioma, and epilepsy, involve oxidative stress and neuronal apoptosis, often leading to long-term disability or death. Emerging studies suggest that oxidative stress may induce epigenetic modifications that contribute to CNS disorders. Non-coding RNAs are epigenetic regulators involved in CNS disorders and have attracted extensive attention. Long non-coding RNAs (lncRNAs) are non-coding RNAs more than 200 nucleotides long and have no protein-coding function. However, these molecules exert regulatory functions at the transcriptional, post-transcriptional, and epigenetic levels. However, the major role of lncRNAs in the pathophysiology of CNS disorders, especially related to oxidative stress, remains unclear. Here, we review the molecular functions of lncRNAs in oxidative stress and highlight lncRNAs that exert positive or negative roles in oxidation/antioxidant systems. This review provides novel insights into the therapeutic potential of lncRNAs that mediate oxidative stress in CNS disorders.

Downregulation of long non-coding RNAs in patients with bipolar disorder

The abnormal function of signaling cascades is currently a candidate in the pathophysiology of bipolar disorder (BD). One of the factors involved in activating these signals is oxidative stress. Some long non-coding RNAs (lncRNA) are involved in the oxidative stress. In this study, we compared expression levels of lincRNA-p21, lincRNA-ROR, and lincRNA-PINT in the peripheral blood mononuclear cells (PBMC) from BD patients (n = 50) and healthy individuals (n = 50). Expression levels of lincRNA-p21, lincRNA-ROR, and lincRNA-PINT were significantly reduced in patients with BD compared to controls. In sex-based analyses, down-regulation of these lncRNAs was revealed only in male BD patients compared to male healthy subjects. Also, in BD patients, all three lncRNAs showed a significant pairwise positive correlation in expression level. The area under curve values for lincRNA-p21, lincRNA-ROR, and lincRNA-PINT was 0.66, 0.75, and 0.66, respectively. Thus, the ROC curve analysis showed that lncRNA-ROR might serve as a diagnostic biomarker for distinguishing between BD patients and controls. Altogether, the current study proposes a role for lincRNA-p21, lincRNA-ROR, and lincRNA-PINT in the pathogenesis of bipolar disorder. Moreover, the peripheral expression of these lncRNAs might be useful as potential biomarkers for BD.

LncRNA: a new perspective on the study of neurological diseases

Long non-coding RNAs (lncRNAs) are a class of non-coding RNA with a length greater than 200 nt. It has a mRNA-like structure, formed by splicing after transcription, and contains a polyA tail and a promoter, of whom promoter plays a role by binding transcription factors. LncRNAs' sequences are low in conservation, and other species can only find a handful of the same lncRNAs as humans, and there are different splicing ways during the differentiation of identical species, with spatiotemporal expression specificity. With developing high-throughput sequencing and bioinformatics, found that more and more lncRNAs associated with nervous system disease. This article deals with the regulation of certain lncRNAs in the nervous system disease, by mean of to understand its mechanism of action, and the pathogenesis of some neurological diseases have a fresh understanding, deposit a foundation for resulting research and clinical treatment of disease.

A new perspective on depression and neuroinflammation: Non-coding RNA

The high incidence and relapse rate of depression, as well comorbidity with other diseases, has made depression one of the primary causes of years of life lived with disability. Moreover, the unknown biological mechanism of depression has made treatment difficult. Neuroinflammation is important in the pathogenesis of depression. Neuroinflammation may affect depression by regulating the production of immune factors, immune cell activation, neuron generation, synaptic plasticity, and neurotransmission. Non-coding RNAs (ncRNAs) may be a breakthrough link between depression and neuroinflammation, as ncRNAs participate in these biological changes. We summarize the functions and mechanisms of ncRNAs in neuroinflammation and depression, and predict ncRNAs that may regulate the occurrence and progression of depression through neuritis. These findings not only broaden our understanding of the genetic regulation of depression and neuroinflammation but also provide a new perspective of the underlying mechanism and aid in the design of novel prevention, diagnosis, and treatment strategies.

Insights into the identification of a molecular signature for amyotrophic lateral sclerosis exploiting integrated microRNA profiling of iPSC-derived motor neurons and exosomes

Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disorder characterized by progressive degeneration of motor neurons (MNs). Most cases are sporadic, whereas 10% are familial. The pathological mechanisms underlying the disease are partially understood, but it is increasingly being recognized that alterations in RNA metabolism and deregulation of microRNA (miRNA) expression occur in ALS. In this study, we performed miRNA expression profile analysis of iPSC-derived MNs and related exosomes from familial patients and healthy subjects. We identified dysregulation of miR-34a, miR-335 and miR-625-3p expression in both MNs and exosomes. These miRNAs regulate genes and pathways which correlate with disease pathogenesis, suggesting that studying miRNAs deregulation can contribute to deeply investigate the molecular mechanisms underlying the disease. We also assayed the expression profile of these miRNAs in the cerebrospinal fluid (CSF) of familial (fALS) and sporadic patients (sALS) and we identified a significant dysregulation of miR-34a-3p and miR-625-3p levels in ALS compared to controls. Taken together, all these findings suggest that miRNA analysis simultaneously performed in different human biological samples could represent a promising molecular tool to understand the etiopathogenesis of ALS and to develop new potential miRNA-based strategies in this new propitious therapeutic era.

Roles of Long Non-coding RNAs in the Development of Aging-Related Neurodegenerative Diseases

Aging-related neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and amyotrophic lateral sclerosis (ALS), are gradually becoming the primary burden of society and cause significant health-care concerns. Aging is a critical independent risk factor for neurodegenerative diseases. The pathological alterations of neurodegenerative diseases are tightly associated with mitochondrial dysfunction, inflammation, and oxidative stress, which in turn stimulates the further progression of neurodegenerative diseases. Given the potential research value, lncRNAs have attracted considerable attention. LncRNAs play complex and dynamic roles in multiple signal transduction axis of neurodegeneration. Emerging evidence indicates that lncRNAs exert crucial regulatory effects in the initiation and development of aging-related neurodegenerative diseases. This review compiles the underlying pathological mechanisms of aging and related neurodegenerative diseases. Besides, we discuss the roles of lncRNAs in aging. In addition, the crosstalk and network of lncRNAs in neurodegenerative diseases are also explored.

Circular RNA circ_0070441 regulates MPP+-triggered neurotoxic effect in SH-SY5Y cells via miR-626/IRS2 axis

Circular RNAs (circRNAs) was suggested to play crucial regulatory roles in various human diseases, including Parkinson's disease (PD). This research aimed to investigate the function and potential mechanism of circ_0070441 in PD. MPP⁺ (1-methyl-4-phenylpyridinium)-treated SH-SY5Y cells was used as an in vitro cellular PD model. The expressions of circ_0070441, microRNA (miR)-626 and insulin receptor substrate 2 (IRS2) were measured by quantitative real-time polymerase chain reaction (RT-qPCR) or western blot. Cell Counting Kit-8 (CCK-8) assay, Cytotoxicity Detection Kit (Lactate Dehydrogenase), flow cytometry and Caspase-3 Assay Kit were used to detect cell viability, LDH release, cell apoptosis and caspase-3 activity, respectively. The levels of inflammation-related factors were detected by enzyme-linked immunosorbent assay (ELISA). The correlation among circ_0070441, miR-626 and IRS2 were confirmed by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull-down assay. The levels of circ_0070441 and IRS2 were increased while miR-626 expression was decreased in MPP⁺-treated SH-SY5Y cells in dose- and time-dependent manners. Depletion of circ_0070441 alleviated MPP⁺-triggered neuronal damage by regulating cell apoptosis and inflammation. Circ_0070441 acted as a sponge for miR-626, and IRS2 was a target of miR-626. Besides, the neuroprotective effects of circ_0070441 knockdown or miR-626 overexpression were partly overturned by the suppression of miR-626 or IRS2 overexpression. Moreover, circ_0070441 upregulated IRS2 expression by interacting with miR-626. In summary, circ_0070441 aggravated MPP⁺-triggered neurotoxic effect in SH-SY5Y cells by regulating miR-626/IRS2 axis.

Role of Long Non-coding RNAs in the Pathogenesis of Alzheimer's and Parkinson's Diseases

Neurodegenerative diseases are a diverse group of diseases that are now one of the leading causes of morbidity in the elderly population. These diseases include Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Amyotrophic Lateral Sclerosis (ALS), etc. Although these diseases have a common characteristic feature of progressive neuronal loss from various parts of the brain, they differ in the clinical symptoms and risk factors, leading to the development and progression of the diseases. AD is a neurological condition that leads to dementia and cognitive decline due to neuronal cell death in the brain, whereas PD is a movement disorder affecting neuro-motor function and develops due to the death of the dopaminergic neurons in the brain, resulting in decreased dopamine levels. Currently, the only treatment available for these neurodegenerative diseases involves reducing the rate of progression of neuronal loss. This necessitates the development of efficient early biomarkers and effective therapies for these diseases. Long non-coding RNAs (LncRNAs) belong to a large family of non-coding transcripts with a minimum length of 200 nucleotides. They are implied to be involved in the development of the brain, a variety of diseases, and epigenetic, transcriptional, and posttranscriptional levels of gene regulation. Aberrant expression of lncRNAs in the CNS is considered to play a major role in the development and progression of AD and PD, two of the most leading causes of morbidity among elderly populations. In this mini-review, we discuss the role of various long non-coding RNAs in neurodegenerative diseases, such as Alzheimer's and Parkinson's disease, which can further be studied for the development of potential biomarkers and therapeutic targets for various neurodegenerative diseases.

Ghrelin alleviates 6-hydroxydopamine-induced neurotoxicity in SH-SY5Y cells

Ghrelin is a neuropeptide that has various physiological functions and has been demonstrated to be neuroprotective in a number of neurological disease models. However, the underlying mechanisms of ghrelin in Parkinson’s disease remain largely unexplored. The current study aimed to study the effects of ghrelin in a 6-hydroxydopamine (6-OHDA)-induced Parkinson’s disease model and evaluate the potential underlying mechanisms. In the present study, we treated an SH-SY5Y cell model with 6-OHDA, and observed that pretreatment with different concentrations of ghrelin (1, 10, and 100 nM) for 30 minutes relieved the neurotoxic effects of 6-OHDA, as revealed by Cell Counting Kit-8 and Annexin V/propidium iodide (PI) apoptosis assays. Reverse transcription quantitative polymerase chain reaction and western blot assay results demonstrated that 6-OHDA treatment upregulated α-synuclein and lincRNA-p21 and downregulated TG-interacting factor 1 (TGIF1), which was predicted as a potential transcription regulator of the gene encoding α-synuclein (SNCA). Ghrelin pretreatment was able to reverse the trends caused by 6-OHDA. The Annexin V/PI apoptosis assay results revealed that inhibiting either α-synuclein or lincRNA-p21 expression with small interfering RNA (siRNA) relieved 6-OHDA-induced cell apoptosis. Furthermore, inhibiting lincRNA-p21 also partially upregulated TGIF1. By retrieving information from a bioinformatics database and performing both double luciferase and RNA immunoprecipitation assays, we found that lincRNA-p21 and TGIF1 were able to form a double-stranded RNA-binding protein Staufen homolog 1 (STAU1) binding site and further activate the STAU1-mediated mRNA decay pathway. In addition, TGIF1 was able to transcriptionally regulate α-synuclein expression by binding to the promoter of SNCA. The Annexin V/PI apoptosis assay results showed that either knockdown of TGIF1 or overexpression of lincRNA-p21 notably abolished the neuroprotective effects of ghrelin against 6-OHDA-induced neurotoxicity. Collectively, these findings suggest that ghrelin exerts neuroprotective effects against 6-OHDA-induced neurotoxicity via the lincRNA-p21/TGIF1/α-synuclein pathway.

A putative role for lncRNAs in epigenetic regulation of memory

The central dogma of molecular genetics is defined as encoded genetic information within DNA, transcribed into messenger RNA, which contain the instructions for protein synthesis, thus imparting cellular functionality and ultimately life. This molecular genetic theory has given birth to the field of neuroepigenetics, and it is now well established that epigenetic regulation of gene transcription is critical to the learning and memory process. In this review, we address a potential role for a relatively new player in the field of epigenetic crosstalk - long non-coding RNAs (lncRNAs). First, we briefly summarize epigenetic mechanisms in memory formation and examine what little is known about the emerging role of lncRNAs during this process. We then focus discussions on how lncRNAs interact with epigenetic mechanisms to control transcriptional programs under various conditions in the brain, and how this may be applied to regulation of gene expression necessary for memory formation. Next, we explore how epigenetic crosstalk in turn serves to regulate expression of various individual lncRNAs themselves. To highlight the importance of further exploring the role of lncRNA in epigenetic regulation of gene expression, we consider the significant relationship between lncRNA dysregulation and declining memory reserve with aging, Alzheimer's disease, and epilepsy, as well as the promise of novel therapeutic interventions. Finally, we conclude with a discussion of the critical questions that remain to be answered regarding a role for lncRNA in memory.

Regulatory role of long non coding RNAs (lncRNAs) in neurological disorders: From novel biomarkers to promising therapeutic strategies

Long non coding RNAs (lncRNAs) are non-protein or low-protein coding transcripts that contain more than 200 nucleotides. They representing a large share of the cell's transcriptional output, demonstrate functional attributes viz. tissue-specific expression, determination of cell fate, controlled expression, RNA processing and editing, dosage compensation, genomic imprinting, conserved evolutionary traits etc. These long non coding variants are well associated with pathogenicity of various diseases including the neurological disorders like Alzheimer's disease, schizophrenia, Huntington's disease, Parkinson's disease etc. Neurological disorders are widespread and there knowing the underlying mechanisms become crucial. The lncRNAs take part in the pathogenesis by a plethora of mechanisms like decoy, scaffold, mi-RNA sequestrator, histone modifiers and in transcriptional interference. Detailed knowledge of the role of lncRNAs can help to use them further as novel biomarkers for therapeutic aspects. Here, in this review we discuss regulation and functional roles of lncRNAs in eight neurological diseases and psychiatric disorders, and the mechanisms by which they act. With these, we try to establish their roles as potential markers and viable diagnostic tools in these disorders.

Long Noncoding RNAs in Neurodegenerative Diseases: Pathogenesis and Potential Implications as Clinical Biomarkers

Neurodegenerative diseases (NDDs), including Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and amyotrophic lateral sclerosis (ALS), are progressive and ultimately fatal. NDD onset is influenced by several factors including heredity and environmental cues. Long noncoding RNAs (lncRNAs) are a class of noncoding RNA molecules with: (i) lengths greater than 200 nucleotides, (ii) diverse biological functions, and (iii) highly conserved structures. They directly interact with molecules such as proteins and microRNAs and subsequently regulate the expression of their targets at the genetic, transcriptional, and post-transcriptional levels. Emerging studies indicate the important roles of lncRNAs in the progression of neurological diseases including NDDs. Additionally, improvements in detection technologies have enabled quantitative lncRNA detection and application to circulating fluids in clinical settings. Here, we review current research on lncRNAs in animal models and patients with NDDs. We also discuss the potential applicability of circulating lncRNAs as biomarkers in NDD diagnostics and prognostics. In the future, a better understanding of the roles of lncRNAs in NDDs will be essential to exploit these new therapeutic targets and improve noninvasive diagnostic methods for diseases.

The epigenetic mechanisms involved in mitochondrial dysfunction: Implication for Parkinson's disease

Mitochondrial dysfunction is one of the crucial factors involved in PD’s pathogenicity, which emerges from a combination of genetic and environmental factors. These factors cause differential molecular expression in neurons, such as varied transcriptional regulation of genes, elevated oxidative stress, α‐synuclein aggregation and endogenous neurotoxins release, which induces epigenetic modifications and triggers energy crisis by damaging mitochondria of the dopaminergic neurons (DN). So far, these events establish a complicated relationship with underlying mechanisms of mitochondrial anomalies in PD, which has remained unclear for years and made PD diagnosis and treatment extremely difficult. Therefore, in this review, we endeavored to discuss the complex association of epigenetic modifications and other associated vital factors in mitochondrial dysfunction. We propose a hypothesis that describes a vicious cycle in which mitochondrial dysfunction and oxidative stress act as a hub for regulating DA neuron's fate in PD. Oxidative stress triggers the release of endogenous neurotoxins (CTIQs) that lead to mitochondrial dysfunction along with abnormal α‐synuclein aggregation and epigenetic modifications. These disturbances further intensify oxidative stress and mitochondrial damage, amplifying the synthesis of CTIQs and works vice versa. This vicious cycle may result in the degeneration of DN to hallmark Parkinsonism. Furthermore, we have also highlighted various endogenous compounds and epigenetic marks (neurotoxic and neuroprotective), which may help for devising future diagnostic biomarkers and target specific drugs using novel PD management strategies.

Downregulation of long noncoding RNA SNHG7 protects against inflammation and apoptosis in Parkinson's disease model by targeting the miR-425-5p/TRAF5/NF-κB axis

Accumulated evidence has manifested that long noncoding RNA (lncRNA) is involved in the progress of Parkinson's disease (PD). SNHG7, a novel lncRNA, has been found to be involved in tumorigenesis. However, SNHG7 expression and its functional effects on PD remain uncharted. Rotenone (Rot) was adopted to construct PD models in Sprague-Dawley (SD) rats and SH-SY5Y cells, respectively. The expression levels of caspase 3, tyrosine hydroxylase (TH), ionized calcium-binding adapter molecule 1 (Iba1) in SD rat striatum were measured via immunohistochemistry and western blot. Additionally, the expressions of inflammatory cytokines (interleukin 1β [IL-1β], IL-6, tumor necrosis factor α) and oxidative stress factors (malondialdehyde, superoxide dismutase, and glutathione peroxidase) in the brain tissues were examined using real-time polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Moreover, the protein levels of tumor necrosis factor receptor-associated factor (TRAF5), I-κB, nuclear factor-κB (NF-κB), HO-1, Nrf2 were detected via western blot. Bioinformatics was applied to predict the targeting relationship between SNHG7, miR-425-5p, and TRAF5. Dual-luciferase activity assay and RNA immunoprecipitation assays were conducted to verify their interactions. In comparison to healthy donors, SNHG7 was found upregulated while miR-425-5p expression was downregulated in PD patients. Functional experiments confirmed that SNHG7 downregulation or miR-425-5p overexpression attenuated neuronal apoptosis in the Rot-mediated PD model, TH-positive cell loss, and microglial activation by mitigating inflammation and oxidative stress. Mechanistically, SNHG7 served as a competitive endogenous RNA by sponging miR-425-5p and promoted TRAF5 mediated inflammation and oxidative stress. Inhibition of SNHG7 ameliorated neuronal apoptosis in PD through relieving miR-425-5p/TRAF5/NF-κB signaling pathway modulated inflammation and oxidative stress, and similar results were observed in the Rot-mediated rat model of PD.

lncRNA NEAT1 prompts autophagy and apoptosis in MPTP-induced Parkinson's disease by impairing miR-374c-5p

Long non-coding RNAs (lncRNAs) play biological roles in brain disorder and neurodegenerative diseases. As the functions of lncRNA NEAT1 in Parkinson's disease (PD) remain unknown, in the present study, we aimed to explore the roles and underlying molecular mechanisms of NEAT1 in PD. A PD mouse model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and a cell model of SH-SY5Y induced by N-methyl-4-phenylpyridinium (MPP+) were established. The ratio of tyrosine hydroxylase (TH+) cells was determined by immunofluorescence assay, and the behavioral changes in mice were observed using pole tests and rotarod tests. The cellular viability and apoptosis of SH-SY5Y were detected by MTT assay and flow cytometric analysis, respectively, and the number of autophagosomes was subsequently measured by transmission electron microscopy. High-performance liquid chromatography was performed to detect the content of dopamine, and a dual-luciferase reporter assay was used to clarify the target of NEAT1 simultaneously. The results demonstrated that the level of NEAT1 was upregulated in the MPTP-induced PD mice, dopamine neurons, and the SH-SY5Y cells treated with MPP+, whereas the level of miR-374c-5p was downregulated. NEAT1 level was positively correlated with MPP+ in a concentration-dependent manner. NEAT1 inhibition efficiently facilitated cell proliferation but inhibited apoptosis and autophagy in the MPP+-treated SH-SY5Y cells. Additionally, silencing of NEAT1 increased the TH+ rate of neurons and suppressed autophagy greatly in PD mice. As a possible target of NEAT1, miR-374c-5p could impact on the apoptosis and autophagy of the SH-SY5Y cells. NEAT1 inhibition upregulated the expression of miR-374c-5p, enhanced SH-SY5Y cell viability, and repressed autophagy and apoptosis in MPTP-induced PD mice. These findings indicated a potential therapeutic role of NEAT1 in treating PD.

Long non-coding RNA: An underlying bridge linking neuroinflammation and central nervous system diseases

Central nervous system (CNS) diseases are responsible for a large proportion of morbidity and mortality worldwide. CNS diseases caused by intrinsic and extrinsic stimuli stimulate the resident immune cells including microglia and astrocyte, resulting in neuroinflammation that exacerbates the progression of diseases. Recent evidence reveals the aberrant expression patterns of long non-coding RNAs (lncRNAs) in the damaged tissues following CNS diseases. It was also proposed that lncRNAs possessed immune-modulatory activities by directly or indirectly affecting various effector proteins including transcriptional factor, acetylase, protein kinase, phosphatase, etc. In addition, lncRNAs can form a sophisticated network by interacting with other molecules to regulate the expression or activation of downstream immune response pathways. However, the major roles of lncRNAs in CNS pathophysiologies are still elusive, especially in neuroinflammation. Herein, we tend to review some potential roles of lncRNAs in modulating neuroinflammation based on current evidence in various CNS diseases, in order to provide novel explanations for the initiation and progression of CNS diseases and help to establish therapeutic strategies targeting neuroinflammation.

Long non-coding RNAs in neurodegenerative diseases

Neurodegenerative diseases are gradually becoming the main burden of society. The morbidity and mortality caused by neurodegenerative diseases remain significant health-care concerns. For most neurodegenerative diseases, there are no effective treatments. Over the past few decades, in a quest to exploit efficacious disease-modifying therapies for the treatment of neurodegenerative diseases, disease mechanisms, reliable biomarkers and therapeutic targets have become a research priority. At present, lncRNA is an area with potential research value. In this article, we first summarize some of the existing results of research into lncRNAs, including origin, molecular characteristics, location types, and functional types. We then introduce the possible functions of lncRNAs in different neurodegenerative diseases. Furthermore, some lncRNAs which show promise as biomarkers or potential therapeutic targets are systematically summarized.

Epigenetic Regulation of Neuroinflammation in Parkinson's Disease

Neuroinflammation is one of the most significant factors involved in the initiation and progression of Parkinson's disease. PD is a neurodegenerative disorder with a motor disability linked with various complex and diversified risk factors. These factors trigger myriads of cellular and molecular processes, such as misfolding defective proteins, oxidative stress, mitochondrial dysfunction, and neurotoxic substances that induce selective neurodegeneration of dopamine neurons. This neuronal damage activates the neuronal immune system, including glial cells and inflammatory cytokines, to trigger neuroinflammation. The transition of acute to chronic neuroinflammation enhances the susceptibility of inflammation-induced dopaminergic neuron damage, forming a vicious cycle and prompting an individual to PD development. Epigenetic mechanisms recently have been at the forefront of the regulation of neuroinflammatory factors in PD, proposing a new dawn for breaking this vicious cycle. This review examined the core epigenetic mechanisms involved in the activation and phenotypic transformation of glial cells mediated neuroinflammation in PD. We found that epigenetic mechanisms do not work independently, despite being coordinated with each other to activate neuroinflammatory pathways. In this regard, we attempted to find the synergic correlation and contribution of these epigenetic modifications with various neuroinflammatory pathways to broaden the canvas of underlying pathological mechanisms involved in PD development. Moreover, this study highlighted the dual characteristics (neuroprotective/neurotoxic) of these epigenetic marks, which may counteract PD pathogenesis and make them potential candidates for devising future PD diagnosis and treatment.

Inhibition of Long Non-Coding RNA KCNQ1OT1 Attenuates Neuroinflammation and Neuronal Apoptosis Through Regulating NLRP3 Expression via Sponging miR-30e-3p

Background

Neuroinflammation and neuronal apoptosis are considered as the critical factors in the pathogenesis of multiple neurological diseases. Recent studies have shown that long non-coding RNA (lncRNA) plays a crucial part in neuroinflammation and neuronal apoptosis.

Methods

The expression levels of lncRNA KCNQ1OT1, miR-30e-3p and NLRP3 in lipopolysaccharide (LPS)-induced HMC3 cells were analyzed using RT-qPCR. MTT assay, LDH release assay and ELISA were used to assess the effect of KCNQ1OT1 and miR-30e-3p on neuroinflammation and neuronal apoptosis. The targeted regulatory relationships among KCNQ1OT1, miR-30e-3p and NLRP3 were evaluated by bioinformatics analysis, dual-luciferase reporter gene assay, RT-qPCR and Western blot.

Results

In LPS-induced HMC3 cells, the expression levels of KCNQ1OT1 and NLRP3 were increased, while the expression level of miR-30e-3p was reduced. Knockdown of KCNQ1OT1 alleviated LPS-induced apoptosis and neuroinflammation of HMC3 cells, accompanied by increased cell viability, low LDH release and reduced cell apoptosis rate, and reduced levels of TNF-α, IL-1β and IL-6. Overexpression of miR-30e-3p had a similar effect. Additionally, KCNQ1OT1 could bind with miR-30e-3p and repress its expression in HMC3 cells, and KCNQ1OT1 overexpression counteracted miR-30e-3p’s inhibitory effect on LPS-induced neuronal damage and inflammatory response in HMC3 cells. Furthermore, KCNQ1OT1 could positively regulate the expression of NLRP3 via repressing miR-30e-3p.

Conclusion

Inhibition of KCNQ1OT1 could reduce neuroinflammation and neuronal apoptosis induced by LPS in HMC3 cells by regulating miR-30e-3p/NLRP3 pathway, suggesting that KCNQ1OT1 and miR-30e-3p could serve as promising therapeutic targets for treating neurological diseases.

LncRNA p21, downregulating miR-181b, aggravates neuropathic pain by upregulating Tnfaip1 and inhibit the AKT/CREB axis

Recently, there is evidence that long non-coding RNA p21 may play a regulatory role in the development of neuropathic pain (NPP), but it remains to be studied. In this study, we found that lncRNA p21 and tumor necrosis factor alpha-induced protein 1 (Tnfaip1) expression were up-regulated and miR-181b expression was down-regulated in lipopolysaccharide (LPS)-induced and activated BV-2 microglia. The results of flow cytometry and ELISA suggested that overexpression of lncRNA p21 or Tnfaip1 promoted apoptosis and inflammatory factors secretion, and miR-181b overexpression inhibited apoptosis and secretion of inflammatory factors. Luciferase reporter gene analysis validated the adsorption of miR-181b by lncRNA p21. In addition, the targeting relationship between miR-181b and Tnfaip1 was determined. Next, the up-regulation of lncRNA p21 and miR-181b was used as a reversal experiment, and the results suggested that the up-regulation of miR-181b attenuated the promoting effect of lncRNA p21 and Tnfaip1 on apoptosis and inflammatory response, which may be related to the activation of AKT/cAMP response element binding protein (CREB) axis. Finally, the rat model of SNL with lncRNA p21 knockdown was constructed, and the results of paw retraction mechanical threshold (PWMT) and paw retraction thermal latency (PWTL) measurements showed that knockdown of lncRNA p21 alleviated neuropathic pain in rats. In conclusion, our study found that the lncRNA p21/miR-181b/Tnfaip1 axis probably plays an important role in the progression of neuropathic pain, among which lncRNA p21 may become a new insight in the treatment of neuropathic pain.

Overview of host miRNA properties and their association with epigenetics, long non-coding RNAs, and Xeno-infectious factors

MicroRNA-derived structures play impressive roles in various biological processes. So dysregulation of miRNAs can lead to different human diseases. Recent studies have extended our comprehension of the control of miRNA function and features. Here, we overview some remarkable miRNA properties that have potential implications for the miRNA functions, including different variants of a miRNA called isomiRs, miRNA arm selection/arm switching, and the effect of these factors on miRNA target selection. Besides, we review some aspects of miRNA interactions such as the interaction between epigenetics and miRNA (different miRNAs and their related processing enzymes are epigenetically regulated by multiple DNA methylation enzymes. moreover, DNA methylation could be controlled by diverse mechanisms related to miRNAs), direct and indirect crosstalk between miRNA and lnc (Long Non-Coding) RNAs as a further approach to conduct intercellular regulation called "competing endogenous RNA" (ceRNA) that is involved in the pathogenesis of different diseases, and the interaction of miRNA activities and some Xeno-infectious (virus/bacteria/parasite) factors, which result in modulation of the pathogenesis of infections. This review provides some related studies to a better understanding of miRNA involvement mechanisms and overcoming the complexity of related diseases that may be applicable and useful to prognostic, diagnostic, therapeutic purposes and personalized medicine in the future.

Long Non-coding RNAs in Parkinson's Disease

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder and is associated with a range of motor and non-motor clinical symptoms. The underlying molecular pathogenesis of PD involves a variety of pathways and mechanisms, including α-synuclein proteostasis, mitochondrial dysfunction, oxidative stress, autophagy and apoptosis, neuroinflammation, and epigenetic regulation. Long non-coding RNAs (lncRNAs) are involved in the regulation of multiple pathological processes of PD. In this review, we provide an overview of large-scale studies on lncRNA expression profiling in PD patients and models, as well as highlight the impacts of lncRNAs on the pathogenesis of PD, which could provide basic information regarding the putative lncRNA-based biomarkers and therapeutic targets for the early diagnosis and treatment strategies for PD.

NEAT1 Decreasing Suppresses Parkinson's Disease Progression via Acting as miR-1301-3p Sponge

Long non-coding RNA (lncRNA) plays a crucial role in multiple disorders, while the role of it in Parkinson's disease (PD) is still unclear. Here, the increased lncRNA NEAT1 was discovered in MPP+-induced SH-SY5Y cells. Then, we proved that NEAT1 decreasing suppressed MPP+-induced neuronal apoptosis, upregulation of α-syn and activation of NLRP3 inflammasome. Rescue experiments shown that the inhibition of NEAT1 decreasing to MPP+-induced activation of NLRP3 inflammasome and subsequent neuronal apoptosis can be reversed by overexpressed α-syn. Subsequently, we indicated the interaction between NEAT1 and miR-1301-3p, as well as between NEAT1 and miR-5047. Interesting, we found that NEAT1 decreasing repressed the expression of GJB1, a downstream target of miR-1301-3p and miR-5047, through promoting miR-1301-3p rather than miR-5047 expression. Finally, we transfected miR-1301-3p inhibitor to MPP+-induced SH-SY5Y cells following si-NEAT1, and found that downregulation of NEAT1 repressed α-syn-mediated the activation of NLRP3 inflammasome through regulating miR-1301-3p/GJB1 signaling pathway. Overall, our data demonstrated that NEAT1 decreasing effectively suppressed MPP+-induced neuronal apoptosis. Mechanismly, downregulation of NEAT1 repressed α-syn-induced activation of NLRP3 inflammasome via inhibiting the expression of GJB1 by targeting miR-1301-3p. Our study supported a new and reliable evidence for lncRNA NEAT1 as a potential target for PD treatment.

LncRNA XIST sponges miR-199a-3p to modulate the Sp1/LRRK2 signal pathway to accelerate Parkinson's disease progression

In vitro and in vivo models of Parkinson’s disease were established to investigate the effects of the lncRNA XIST/miR-199a-3p/Sp1/LRRK2 axis. The binding between XIST and miR-199a-3p as well as miR-199a-3p and Sp1 were examined by luciferase reporter assay and confirmed by RNA immunoprecipitation analysis. Following the Parkinson’s disease animal behavioural assessment by suspension and swim tests, the brain tissue injuries were evaluated by hematoxylin and eosin, TdT-mediated dUTP-biotin nick end labelling, and tyrosine hydroxylase stainings. The results indicated that miR-199a-3p expression was downregulated, whereas that of XIST, Sp1 and LRRK2 were upregulated in Parkinson’s disease. Moreover, miR-199a-3p overexpression or XIST knockdown inhibited the cell apoptosis induced by MPP⁺ treatment and promoted cell proliferation. The neurodegenerative defects were significantly recovered by treating the cells with shXIST or shSp1, whereas miR-199a-3p inhibition or Sp1 and LRRK2 overexpression abrogated these beneficial effects. Furthermore, the results of our in vivo experiments confirmed the neuroprotective effects of shXIST and miR-199a-3p against MPTP-induced brain injuries, and the Parkinson’s disease behavioural symptoms were effectively alleviated upon shXIST or miR-199a-3p treatment. In summary, the results of the present study showed that lncRNA XIST sponges miR-199a-3p to modulate Sp1 expression and further accelerates Parkinson’s disease progression by targeting LRRK2.

Competing Endogenous RNA Networks as Biomarkers in Neurodegenerative Diseases

Protein aggregation is classically considered the main cause of neuronal death in neurodegenerative diseases (NDDs). However, increasing evidence suggests that alteration of RNA metabolism is a key factor in the etiopathogenesis of these complex disorders. Non-coding RNAs are the major contributor to the human transcriptome and are particularly abundant in the central nervous system, where they have been proposed to be involved in the onset and development of NDDs. Interestingly, some ncRNAs (such as lncRNAs, circRNAs and pseudogenes) share a common functionality in their ability to regulate gene expression by modulating miRNAs in a phenomenon known as the competing endogenous RNA mechanism. Moreover, ncRNAs are found in body fluids where their presence and concentration could serve as potential non-invasive biomarkers of NDDs. In this review, we summarize the ceRNA networks described in Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis and spinocerebellar ataxia type 7, and discuss their potential as biomarkers of these NDDs. Although numerous studies have been carried out, further research is needed to validate these complex interactions between RNAs and the alterations in RNA editing that could provide specific ceRNET profiles for neurodegenerative disorders, paving the way to a better understanding of these diseases.

LncRNA-T199678 Mitigates α-Synuclein-Induced Dopaminergic Neuron Injury via miR-101-3p

Parkinson's disease (PD) is the second most common neurodegenerative disorder characterized by dopaminergic neuron death and the abnormal accumulation and aggregation of α-synuclein (α-Syn) in the substantia nigra (SN). Although the abnormal accumulation of α-Syn can solely promote and accelerate the progress of PD, the underlying molecular mechanisms remain unknown. Mounting evidence confirms that the abnormal expression of long non-coding RNA (lncRNA) plays an important role in PD. Our previous study found that exogenous α-Syn induced the downregulation of lncRNA-T199678 in SH-SY5Y cells via a gene microarray analysis. This finding suggested that lncRNA-T199678 might have a potential pathological role in the pathogenesis of PD. This study aimed to explore the influence of lncRNA-T199678 on α-Syn-induced dopaminergic neuron injury. Overexpression of lncRNA-T199678 ameliorated the neuron injury induced by α-Syn via regulating oxidative stress, cell cycle, and apoptosis. Studies indicate lncRNAs could regulate posttranscriptional gene expression via regulating the downstream microRNA (miRNA). To discover the downstream molecular target of lncRNA-T199678, the following experiment found out that miR-101-3p was a potential target for lncRNA-T199678. Further study showed that the upregulation of lncRNA-T199678 reduced α-Syn-induced neuronal damage through miR-101-3p in SH-SY5Y cells and lncRNA-T199678 was responsible for the α-Syn-induced intracellular oxidative stress, dysfunction of the cell cycle, and apoptosis. All in all, lncRNA-T199678 mitigated the α-Syn-induced dopaminergic neuron injury via targeting miR-101-3p, which contributed to promote PD. Our results highlighted the role of lncRNA-T199678 in mitigating dopaminergic neuron injury in PD and revealed a new molecular target for PD.

Transient Receptor Potential Channels as an Emerging Target for the Treatment of Parkinson's Disease: An Insight Into Role of Pharmacological Interventions

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the symptoms of motor deficits and cognitive decline. There are a number of therapeutics available for the treatment of PD, but most of them suffer from serious side effects such as bradykinesia, dyskinesia and on-off effect. Therefore, despite the availability of these pharmacological agents, PD patients continue to have an inferior quality of life. This has warranted a need to look for alternate strategies and molecular targets. Recent evidence suggests the Transient Receptor Potential (TRP) channels could be a potential target for the management of motor and non-motor symptoms of PD. Though still in the preclinical stages, agents targeting these channels have shown immense potential in the attenuation of behavioral deficits and signaling pathways. In addition, these channels are known to be involved in the regulation of ionic homeostasis, which is disrupted in PD. Moreover, activation or inhibition of many of the TRP channels by calcium and oxidative stress has also raised the possibility of their paramount involvement in affecting the other molecular mechanisms associated with PD pathology. However, due to the paucity of information available and lack of specificity, none of these agents have gone into clinical trials for PD treatment. Considering their interaction with oxidative stress, apoptosis and excitotoxicity, TRP channels could be considered as a potential future target for the treatment of PD.

LINC00943 knockdown attenuates MPP+-induced neuronal damage via miR-15b-5p/RAB3IP axis in SK-N-SH cells

OBJECTIVES

Parkinson's disease (PD) is a neurodegenerative problem correlated with neuronal damage. Long noncoding RNAs (lncRNAs) are implicated in neuronal damage in PD development. This research aims to analyze the function and mechanism of LINC00943 in 1-methyl-4-phenylpyridinium (MPP⁺)-caused neuronal injury.

METHODS

MPP⁺-challenged SK-N-SH cells served as a PD-like model of neuronal damage. LINC00943, microRNA-15b-5p (miR-15b-5p) and RAB3A interacting protein (RAB3IP) abundances were examined via quantitative reverse transcription polymerase chain reaction or western blot. MPP⁺-caused neuronal damage was assessed via cell viability, apoptosis, inflammatory injury and oxidative injury. The association between miR-15b-5p and LINC00943 or RAB3IP was determined via dual-luciferase reporter analysis and RNA immunoprecipitation.

RESULTS

LINC00943 abundance was up-regulated in MPP⁺-challenged SK-N-SH cells. LINC00943 silence alleviated MPP⁺-caused decrease of cell viability and elevation of apoptosis, inflammatory injury and oxidative injury. miR-15b-5p was inhibited via LINC00943, and miR-15b-5p inhibition reversed knockdown of LINC00943-mediated suppression of MPP⁺-induced neuronal damage. RAB3IP was targeted via miR-15b-5p, and LINC00943 could regulate RAB3IP via miR-15b-5p. miR-15b-5p addition mitigated MPP⁺-induced neuronal damage through decreasing RAB3IP.

CONCLUSION

LINC00943 inhibition alleviated MPP⁺-induced neuronal injury via miR-15b-5p/RAB3IP axis, indicating a potential target for treatment of PD.

Non-Coding RNAs as Sensors of Oxidative Stress in Neurodegenerative Diseases

Oxidative stress (OS) results from an imbalance between the production of reactive oxygen species and the cellular antioxidant capacity. OS plays a central role in neurodegenerative diseases, where the progressive accumulation of reactive oxygen species induces mitochondrial dysfunction, protein aggregation and inflammation. Regulatory non-protein-coding RNAs (ncRNAs) are essential transcriptional and post-transcriptional gene expression controllers, showing a highly regulated expression in space (cell types), time (developmental and ageing processes) and response to specific stimuli. These dynamic changes shape signaling pathways that are critical for the developmental processes of the nervous system and brain cell homeostasis. Diverse classes of ncRNAs have been involved in the cell response to OS and have been targeted in therapeutic designs. The perturbed expression of ncRNAs has been shown in human neurodegenerative diseases, with these changes contributing to pathogenic mechanisms, including OS and associated toxicity. In the present review, we summarize existing literature linking OS, neurodegeneration and ncRNA function. We provide evidences for the central role of OS in age-related neurodegenerative conditions, recapitulating the main types of regulatory ncRNAs with roles in the normal function of the nervous system and summarizing up-to-date information on ncRNA deregulation with a direct impact on OS associated with major neurodegenerative conditions.

Tristetraprolin destabilizes NOX2 mRNA and protects dopaminergic neurons from oxidative damage in Parkinson's disease

Tristetraprolin (TTP), an RNA-binding protein encoded by the ZFP36 gene, is vital for neural differentiation; however, its involvement in neurodegenerative diseases such as Parkinson's disease (PD) remains unclear. To explore the role of TTP in PD, an in vitro 1-methyl-4-phenylpyridinium (MPP⁺ ) cell model and an in vivo 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) of PD were used. Transfection of small interfering (si)-TTP RNA upregulated pro-oxidative NOX2 expression and ROS formation, downregulated anti-oxidative GSH and SOD activity；si-TTP upregulated pro-apoptotic cleaved-caspase-3 expression, and downregulated antiapoptotic Bcl-2 expression; while overexpression (OE)-TTP lentivirus caused opposite effects. Through database prediction, luciferase experiment, RNA immunoprecipitation (RIP), and mRNA stability analysis, we evaluated the potential binding sites of TTP to 3'-untranslated regions (3'-UTR) of NOX2 mRNA. TTP affected the NOX2 luciferase activity by binding to two sites in the NOX2 3'-UTR. RIP-qPCR confirmed TTP binding to both sites, with a higher affinity for site-2. In addition, TTP reduced the NOX2 mRNA stability. si-NOX2 and antioxidant N-acetyl cysteine (NAC) reversed si-TTP-induced cell apoptosis. In MPTP-treated mice, TTP expression increased and was co-located with dopaminergic neurons. TTP also inhibited NOX2 and decreased the oxidative stress in vivo. In conclusion, TTP protects against dopaminergic oxidative injury by promoting NOX2 mRNA degradation in the MPP⁺ /MPTP model of PD, suggesting that TTP could be a potential therapeutic target for regulating the oxidative stress in PD.

Non-Coding RNAs in the Brain-Heart Axis: The Case of Parkinson's Disease

Parkinson's disease (PD) is a complex and heterogeneous disorder involving multiple genetic and environmental influences. Although a wide range of PD risk factors and clinical markers for the symptomatic motor stage of the disease have been identified, there are still no reliable biomarkers available for the early pre-motor phase of PD and for predicting disease progression. High-throughput RNA-based biomarker profiling and modeling may provide a means to exploit the joint information content from a multitude of markers to derive diagnostic and prognostic signatures. In the field of PD biomarker research, currently, no clinically validated RNA-based biomarker models are available, but previous studies reported several significantly disease-associated changes in RNA abundances and activities in multiple human tissues and body fluids. Here, we review the current knowledge of the regulation and function of non-coding RNAs in PD, focusing on microRNAs, long non-coding RNAs, and circular RNAs. Since there is growing evidence for functional interactions between the heart and the brain, we discuss the benefits of studying the role of non-coding RNAs in organ interactions when deciphering the complex regulatory networks involved in PD progression. We finally review important concepts of harmonization and curation of high throughput datasets, and we discuss the potential of systems biomedicine to derive and evaluate RNA biomarker signatures from high-throughput expression data.