Mitochondrial ROS-mediated post-transcriptional regulation of α-synuclein through miR-7 and miR-153

Unlocking Parkinson's disease: the role of microRNAs in regulation, diagnosis, and therapy

Parkinson's disease (PD), the second most prevalent neurodegenerative disorder globally, imposes substantial healthcare burdens on aging populations. The pathogenesis of PD is complex and multifaceted. Emerging evidence highlights microRNA (miRNA) dysregulation as a critical regulatory layer that drives PD progression. These small noncoding RNAs mediate posttranscriptional gene regulation through target mRNA binding, inducing either transcript degradation or translational repression. This article reviews the distinct miRNAs that orchestrate PD pathogenesis by disrupting mitochondrial homeostasis, lysosomal clearance pathways, ferroptosis regulation, and neuroinflammatory responses. Notably, some miRNAs achieve these effects by selectively targeting risk genes central to PD pathology. Crucially, certain miRNAs exhibit aberrant expression patterns in the brain tissues and biofluids of PD patients or models, highlighting their potential as minimally invasive diagnostic or prognostic biomarkers. Furthermore, this review highlights the novel role of exosomes as miRNA carriers, offering innovative possibilities for PD therapeutic interventions. With the deepening understanding of miRNA research advances in PD, we propose that these insights may not only inform PD treatment strategies but also hold relevance for addressing other genetic disorders.

Biological Function Analysis of MicroRNAs and Proteins in the Cerebrospinal Fluid of Patients with Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by alpha-synuclein aggregation into Lewy bodies in the neurons. Cerebrospinal fluid (CSF) is considered the most suited source for investigating PD pathogenesis and identifying biomarkers. While microRNA (miRNA) profiling can aid in the investigation of post-transcriptional regulation in neurodegenerative diseases, information on miRNAs in the CSF of patients with PD remains limited. This review combines miRNA analysis with proteomic profiling to explore the collective impact of CSF miRNAs on the neurodegenerative mechanisms in PD. We constructed separate networks for altered miRNAs and proteomes using a bioinformatics method. Altered miRNAs were poorly linked to biological functions owing to limited information; however, changes in protein expression were strongly associated with biological functions. Subsequently, the networks were integrated for further analysis. In silico prediction from the integrated network revealed relationships between miRNAs and proteins, highlighting increased reactive oxygen species generation, neuronal loss, and neurodegeneration and suppressed ATP synthesis, mitochondrial function, and neurotransmitter release in PD. The approach suggests the potential of miRNAs as biomarkers for critical mechanisms underlying PD. The combined strategy could enhance our understanding of the complex biochemical networks of miRNAs in PD and support the development of diagnostic and therapeutic strategies for precision medicine.

Epigenetic reprogramming of mtDNA and its etiology in mitochondrial diseases

Mitochondrial functionality and its regulation are tightly controlled through a balanced crosstalk between the nuclear and mitochondrial DNA interactions. Epigenetic signatures like methylation, hydroxymethylation and miRNAs have been reported in mitochondria. In addition, epigenetic signatures encoded by nuclear DNA are also imported to mitochondria and regulate the gene expression dynamics of the mitochondrial genome. Alteration in the interplay of these epigenetic modifications results in the pathogenesis of various disorders like neurodegenerative, cardiovascular, metabolic disorders, cancer, aging and senescence. These modifications result in higher ROS production, increased mitochondrial copy number and disruption in the replication process. In addition, various miRNAs are associated with regulating and expressing important mitochondrial gene families like COX, OXPHOS, ND and DNMT. Epigenetic changes are reversible and therefore therapeutic interventions like changing the target modifications can be utilized to repair or prevent mitochondrial insufficiency by reversing the changed gene expression. Identifying these mitochondrial-specific epigenetic signatures has the potential for early diagnosis and treatment responses for many diseases caused by mitochondrial dysfunction. In the present review, different mitoepigenetic modifications have been discussed in association with the development of various diseases by focusing on alteration in gene expression and dysregulation of specific signaling pathways. However, this area is still in its infancy and future research is warranted to draw better conclusions.

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

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

Association of Serum Extracellular Vesicle miRNAs with Cognitive Functioning and Quality of Life in Parkinson's Disease

The identification of mechanisms associated with Parkinson disease (PD) development in cognitive functioning would be of great usefulness to clarify PD pathogenesis and to develop preventive and therapeutic strategies. In this study, blood serum extracellular vesicle (EV) levels of the candidate microRNAs (small noncoding RNAs that play a role in gene expression regulation):,miR-7, miR-21, miR-153, miR-155, miR-200a and miR-214, have been investigated for association with PD in a group of 93 patients with cognitive parameters, PD symptoms, affected quality of life and some clinical characteristics. MiRNA was extracted from patients' blood serum EVs, transcribed into cDNA and their expression was evaluated using RT-PCR. The miR-153 and miR-200a showed the most plausible correlations with cognitive functioning parameters such as general intellectual functioning, psychomotor speed, mental flexibility, and nonverbal executive functions. Moreover, lower levels of miR-153 were associated with attention span, working memory and psychomotor speed with learning. Increased levels of miR-200a, miR-7, miR-214, and miR-155 were also linked with neurological functioning, such as bradykinesia, tremor, balance and others. Despite the fact that due to small sample size, our results should be considered as preliminary, our study suggests that miRNA expression in EVs could be associated with symptom severity, cognitive impairment and quality of life in PD.

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.

Assessment of tRNAThr and tRNAGln Variants and Mitochondrial Functionality in Parkinson's Disease (PD) Patients of Tamil Nadu Population

Parkinson's disease (PD) is speculated with genetic and environmental factors. At molecular level, the mitochondrial impact is stated to be one of the causative reasons for PD. In this study, we investigated the mitochondrial membrane potential (MMP), reactive oxygen species (ROS) and adenosine triphosphate (ATP) levels along with mitochondrial tRNA alterations among three age categories of PD. By determining the genetic and organellar functionality using molecular techniques, the ROS levels were reported to be high with decreased MMP and ATP in the late-onset age group than in other two age categories. Likewise, the tRNA significancy in tRNAThr and tRNAGln was noticed with C4335T and G15927A mutations in late-onset and early-onset PD groups respectively. Therefore, from the findings, ageing has shown a disruption in tRNA metabolism leading to critical functioning of ATP synthesis and MMP, causing oxidative stress in PD patients. These physiological outcomes show that ageing has a keen role in the divergence of mitochondrial function, thereby proving a correlation with ageing and maintenance of mitochondrial homeostasis in PD.

Shared Molecular Pathways in Glaucoma and Other Neurodegenerative Diseases: Insights from RNA-Seq Analysis and miRNA Regulation for Promising Therapeutic Avenues

Advances in RNA-sequencing technologies have led to the identification of molecular biomarkers for several diseases, including neurodegenerative diseases, such as Alzheimer's, Parkinson's, Huntington's diseases and Amyotrophic Lateral Sclerosis. Despite the nature of glaucoma as a neurodegenerative disorder with several similarities with the other above-mentioned diseases, transcriptional data about this disease are still scarce. microRNAs are small molecules (~17-25 nucleotides) that have been found to be specifically expressed in the CNS as major components of the system regulating the development signatures of neurodegenerative diseases and the homeostasis of the brain. In this review, we sought to identify similarities between the functional mechanisms and the activated pathways of the most common neurodegenerative diseases, as well as to discuss how those mechanisms are regulated by miRNAs, using RNA-Seq as an approach to compare them. We also discuss therapeutically suitable applications for these disease hallmarks in clinical future studies.

A Glance at Biogenesis and Functionality of MicroRNAs and Their Role in the Neuropathogenesis of Parkinson's Disease

MicroRNAs (miRNAs) are short, noncoding RNA transcripts. Mammalian miRNA coding sequences are located in introns and exons of genes encoding various proteins. As the central nervous system is the largest source of miRNA transcripts in living organisms, miRNA molecules are an integral part of the regulation of epigenetic activity in physiological and pathological processes. Their activity depends on many proteins that act as processors, transporters, and chaperones. Many variants of Parkinson's disease have been directly linked to specific gene mutations which in pathological conditions are cumulated resulting in the progression of neurogenerative changes. These mutations can often coexist with specific miRNA dysregulation. Dysregulation of different extracellular miRNAs has been confirmed in many studies on the PD patients. It seems reasonable to conduct further research on the role of miRNAs in the pathogenesis of Parkinson's disease and their potential use in future therapies and diagnosis of the disease. This review presents the current state of knowledge about the biogenesis and functionality of miRNAs in the human genome and their role in the neuropathogenesis of Parkinson's disease (PD)-one of the most common neurodegenerative disorders. The article also describes the process of miRNA formation which can occur in two ways-the canonical and noncanonical one. However, the main focus was on miRNA's use in in vitro and in vivo studies in the context of pathophysiology, diagnosis, and treatment of PD. Some issues, especially those regarding the usefulness of miRNAs in PD's diagnostics and especially its treatment, require further research. More standardization efforts and clinical trials on miRNAs are needed.

Crosstalk between Oxidative Stress and Aging in Neurodegeneration Disorders

The world population is aging rapidly, and increasing lifespan exacerbates the burden of age-related health issues. On the other hand, premature aging has begun to be a problem, with increasing numbers of younger people suffering aging-related symptoms. Advanced aging is caused by a combination of factors: lifestyle, diet, external and internal factors, as well as oxidative stress (OS). Although OS is the most researched aging factor, it is also the least understood. OS is important not only in relation to aging but also due to its strong impact on neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), Alzheimer's disease (AD), and Parkinson's disease (PD). In this review, we will discuss the aging process in relation to OS, the function of OS in neurodegenerative disorders, and prospective therapeutics capable of relieving neurodegenerative symptoms associated with the pro-oxidative condition.

Novel diagnostic biomarkers related to immune infiltration in Parkinson's disease by bioinformatics analysis

Background

Parkinson's disease (PD) is Pengfei Zhang Liwen Zhao Pengfei Zhang Liwen Zhao a common neurological disorder involving a complex relationship with immune infiltration. Therefore, we aimed to explore PD immune infiltration patterns and identify novel immune-related diagnostic biomarkers.

Materials and methods

Three substantia nigra expression microarray datasets were integrated with elimination of batch effects. Differentially expressed genes (DEGs) were screened using the "limma" package, and functional enrichment was analyzed. Weighted gene co-expression network analysis (WGCNA) was performed to explore the key module most significantly associated with PD; the intersection of DEGs and the key module in WGCNA were considered common genes (CGs). The CG protein-protein interaction (PPI) network was constructed to identify candidate hub genes by cytoscape. Candidate hub genes were verified by another two datasets. Receiver operating characteristic curve analysis was used to evaluate the hub gene diagnostic ability, with further gene set enrichment analysis (GSEA). The immune infiltration level was evaluated by ssGSEA and CIBERSORT methods. Spearman correlation analysis was used to evaluate the hub genes association with immune cells. Finally, a nomogram model and microRNA-TF-mRNA network were constructed based on immune-related biomarkers.

Results

A total of 263 CGs were identified by the intersection of 319 DEGs and 1539 genes in the key turquoise module. Eleven candidate hub genes were screened by the R package "UpSet." We verified the candidate hub genes based on two validation sets and identified six (SYT1, NEFM, NEFL, SNAP25, GAP43, and GRIA1) that distinguish the PD group from healthy controls. Both CIBERSORT and ssGSEA revealed a significantly increased proportion of neutrophils in the PD group. Correlation between immune cells and hub genes showed SYT1, NEFM, GAP43, and GRIA1 to be significantly related to immune cells. Moreover, the microRNA-TFs-mRNA network revealed that the microRNA-92a family targets all four immune-related genes in PD pathogenesis. Finally, a nomogram exhibited a reliable capability of predicting PD based on the four immune-related genes (AUC = 0.905).

Conclusion

By affecting immune infiltration, SYT1, NEFM, GAP43, and GRIA1, which are regulated by the microRNA-92a family, were identified as diagnostic biomarkers of PD. The correlation of these four genes with neutrophils and the microRNA-92a family in PD needs further investigation.

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.

Dysregulation of a Heme Oxygenase-Synuclein Axis in Parkinson Disease

α-Synuclein is a key driver of the pathogenesis of Parkinson disease (PD). Heme oxygenase-1 (HO-1), a stress protein that catalyzes the conversion of heme to biliverdin, carbon monoxide and free ferrous iron, is elevated in PD-affected neural tissues and promotes iron deposition and mitochondrial dysfunction in models of the disease, pathways also impacted by α-synuclein. Elevated expression of human HO-1 in astrocytes of GFAP.HMOX1 transgenic mice between 8.5 and 19 months of age elicits a parkinsonian phenotype characterized by nigrostriatal hypodopaminergia, locomotor incoordination and overproduction of neurotoxic native S129-phospho-α-synuclein. Two microRNAs (miRNA) known to regulate α-synuclein, miR-153 and miR-223, are significantly decreased in the basal ganglia of GFAP.HMOX1 mice. Serum concentrations of both miRNAs progressively decline in wild-type (WT) and GFAP.HMOX1 mice between 11 and 18 months of age. Moreover, circulating levels of miR-153 and miR-223 are significantly lower, and erythrocyte α-synuclein concentrations are increased, in GFAP.HMOX1 mice relative to WT values. MiR-153 and miR-223 are similarly decreased in the saliva of PD patients compared to healthy controls. Upregulation of glial HO-1 may promote parkinsonism by suppressing miR-153 and miR-223, which, in turn, enhance production of neurotoxic α-synuclein. The aim of the current review is to explore the link between HO-1, α-synuclein and PD, evaluating evidence derived from our laboratory and others. HO-1, miR-153 and miR-223 and α-synuclein may serve as potential biomarkers and targets for disease-modifying therapy in idiopathic PD.

Empagliflozin alleviates endoplasmic reticulum stress and augments autophagy in rotenone-induced Parkinson's disease in rats: Targeting the GRP78/PERK/eIF2α/CHOP pathway and miR-211-5p

Empagliflozin, a selective sodium-glucose co-transporter-2 inhibitor, has been demonstrated to provide additional non-glycemic benefits, including neuroprotection. Endoplasmic reticulum (ER) stress is a key player in neurodegeneration and occurs at the crossroads of other pathologic mechanisms; however, its role in the pathogenesis of Parkinson's disease (PD) is still elusive. miR-211-5p regulates neuronal differentiation and viability and was predicted to target CHOP, a downstream effector in the ER stress pathway. For the first time, this study investigated the possible neuroprotective effect of empagliflozin in a rotenone-induced rat model of PD from the perspective of ER stress. Rotenone (1.5 mg/kg) was administered subcutaneously every other day for 3 weeks. Meanwhile, the treated group received empagliflozin 10 mg/kg/day orally for 15 consecutive days post-PD induction. On the molecular level, the ER stress pathway components; GRP78, total and phosphorylated PERK, eIF2α and CHOP, along with miR-211-5p expression were upregulated in the striatum of rotenone-injected rats. Concurrently, the untreated rats showed elevated striatal α-synuclein levels along with diminished autophagy and the proteasome system as evidenced by reduced beclin-1 protein and ELF2/NERF mRNA expression levels. The rotenone-induced striatal oxidative stress and neuroinflammation were expressed by reduced catalase activity and elevated interleukin (IL)-1β levels. miR-211-5p was positively correlated with PERK/eIF2α/CHOP, IL-1β and α-synuclein, while negatively correlated with ELF2/NERF, beclin-1 and catalase activity. Empagliflozin treatment showed a restorative effect on all biochemical alterations and improved the motor function of rats tested by open field, grip strength and footprint gait analysis. In the histopathological examination, empagliflozin increased the intact neuron count and attenuated astrogliosis and microgliosis by reducing the glial fibrillary protein and ionized calcium-binding adaptor protein 1 immunostaining. Conclusively, these results emphasize the neurotherapeutic impact of empagliflozin in PD by moderating the GRP78/PERK/eIF2α/CHOP ER stress pathway, downregulating miR-211-5p, resolving oxidative stress, lessening astrocyte/microglial activation and neuroinflammation, along with augmenting autophagy.

LINC00667 regulates MPP + ‐induced neuronal injury in Parkinson’s disease

Objective

Parkinson’s disease (PD), also known as paralysis tremor, is a chronic disease of the central nervous system. It has been reported that hepatocyte nuclear factor 4 alpha (HNF4A) is upregulated in PD, but its specific function has not been well explored.

Methods

We established an in vitro PD model in SH‐SY5Y cells stimulated with 1‐methyl‐4‐phenylpyridinium (MPP⁺). Meanwhile, the effect of HNF4A on MPP⁺‐treated SH‐SY5Y cell behavior was monitored by functional assays. Mechanism assays were conducted to verify the relationship among LINC00667/miR‐34c‐5p/HNF4A. Rescue experiments validated the regulatory mechanism in PD model.

Results

The results revealed that depletion of HNF4A suppressed cell cytotoxicity and apoptosis caused by MPP⁺. Knockdown of HNF4A recovered MPP⁺‐stimulated oxidative stress and neuroinflammation. Mechanically, HNF4A was targeted and inhibited by miR‐34c‐5p. Furthermore, we found that LINC00667 positively modulated HNF4A expression via sequestering miR‐34c‐5p in MPP⁺‐stimulated SH‐SY5Y cells. Interestingly, the data indicated that HNF4A could transcriptionally activate LINC00667 expression. Rescue experiments presented that miR‐34c‐5p interference or HNF4A overexpression could mitigate the effects of LINC00667 knockdown on cell viability, cytotoxicity, cell apoptosis, oxidative stress, and neuroinflammation in MPP⁺‐treated SH‐SY5Y cells.

Conclusion

Our study first proved LINC00667, miR‐34c‐5p, and HNF4A constructed a positive feedback loop in MPP⁺‐treated SH‐SY5Y cells, enriching our understanding of PD.

MicroRNAs in the pathophysiology of Alzheimer's disease and Parkinson's disease: an overview

Neurodegenerative diseases are characterized by a progressive loss of neurons of the central nervous system (CNS) and serve as a major cause of morbidity, mortality and functional dependence especially among the elderly. Despite extensive research and development efforts, the success rate of clinical pipelines has been very limited. However, microRNAs (miRs) have been proved to be of crucial importance in regulating intracellular pathways for various pathologic conditions including those of a neurodegenerative nature. There is ample evidence of altered levels of various miRs in clinical samples of Alzheimer's disease and Parkinson's disease patients with potentially major clinical implications. In the current review, we aim to summarize the relevant literature on the role of miRs in the pathophysiology of Alzheimer's disease (AD) and Parkinson's disease (PD) as the two globally predominant neurodegenerative conditions.

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.

Extracellular Vesicles and HIV-Associated Neurocognitive Disorders: Implications in Neuropathogenesis and Disease Diagnosis

Extracellular vesicles are heterogeneous cell-derived membranous structures of nanometer size that carry diverse cargoes including nucleic acids, proteins, and lipids. Their secretion into the extracellular space and delivery of their cargo to recipient cells can alter cellular function and intracellular communication. In this review, we summarize the role of extracellular vesicles in the disease pathogenesis of HIV-associated neurocognitive disorder (HAND) by focusing on their role in viral entry, neuroinflammation, and neuronal degeneration. We also discuss the potential role of extracellular vesicles as biomarkers of HAND. Together, this review aims to convey the importance of extracellular vesicles in the pathogenesis of HAND and foster interest in their role in neuroinflammatory diseases.

Role of Mitochondria in Neurodegenerative Diseases: From an Epigenetic Perspective

Mitochondria, the centers of energy metabolism, have been shown to participate in epigenetic regulation of neurodegenerative diseases. Epigenetic modification of nuclear genes encoding mitochondrial proteins has an impact on mitochondria homeostasis, including mitochondrial biogenesis, and quality, which plays role in the pathogenesis of neurodegenerative diseases like Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and amyotrophic lateral sclerosis. On the other hand, intermediate metabolites regulated by mitochondria such as acetyl-CoA and NAD⁺, in turn, may regulate nuclear epigenome as the substrate for acetylation and a cofactor of deacetylation, respectively. Thus, mitochondria are involved in epigenetic regulation through bidirectional communication between mitochondria and nuclear, which may provide a new strategy for neurodegenerative diseases treatment. In addition, emerging evidence has suggested that the abnormal modification of mitochondria DNA contributes to disease development through mitochondria dysfunction. In this review, we provide an overview of how mitochondria are involved in epigenetic regulation and discuss the mechanisms of mitochondria in regulation of neurodegenerative diseases from epigenetic perspective.

The importance of non-coding RNAs in environmental stress-related developmental brain disorders: A systematic review of evidence associated with exposure to alcohol, anesthetic drugs, nicotine, and viral infections

Brain development is a dynamic and lengthy process that includes cell proliferation, migration, neurogenesis, gliogenesis, synaptogenesis, and pruning. Disruption of any of these developmental events can result in long-term outcomes ranging from brain structural changes, to cognitive and behavioral abnormality, with the mechanisms largely unknown. Emerging evidence suggests non-coding RNAs (ncRNAs) as pivotal molecules that participate in normal brain development and neurodevelopmental disorders. NcRNAs such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are transcribed from the genome but not translated into proteins. Many ncRNAs have been implicated as tuners of cell fate. In this review, we started with an introduction of the current knowledge of lncRNAs and miRNAs, and their potential roles in brain development in health and disorders. We then reviewed and discussed the evidence of ncRNA involvement in abnormal brain development resulted from alcohol, anesthetic drugs, nicotine, and viral infections. The complex connections among these ncRNAs were also discussed, along with potential overlapping ncRNA mechanisms, possible pharmacological targets for therapeutic/neuroprotective interventions, and potential biomarkers for brain developmental disorders.

MicroRNAs Involved in Oxidative Stress Processes Regulating Physiological and Pathological Responses

Oxidative stress influences several physiological and pathological cellular events, including cell differentiation, excessive growth, proliferation, apoptosis, and the inflammatory response. Therefore, oxidative stress is involved in the pathogenesis of various diseases, including pulmonary fibrosis, epilepsy, hypertension, atherosclerosis, Parkinson's disease, cardiovascular disease, and Alzheimer's disease. Recent studies have shown that several microRNAs (miRNAs) are involved in developing various diseases caused by oxidative stress and that miRNAs may be helpful to determine the inflammatory characteristics of immune responses during infection and disease. This review describes the known effects of miRNAs on reactive oxygen species to induce oxidative stress and the miRNA regulatory mechanisms involved in the uncoupling of Keap1-Nrf2 complexes. Finally, we summarized the functions of miRNAs in several antioxidant genes. Understanding the crosstalk between miRNAs and oxidative stress-inducing factors during physiological and pathological cellular events may have implications for designing more effective treatments for immune diseases.

Mitophagy and Oxidative Stress: The Role of Aging

Mitochondrial dysfunction is a hallmark of aging. Dysfunctional mitochondria are recognized and degraded by a selective type of macroautophagy, named mitophagy. One of the main factors contributing to aging is oxidative stress, and one of the early responses to excessive reactive oxygen species (ROS) production is the induction of mitophagy to remove damaged mitochondria. However, mitochondrial damage caused at least in part by chronic oxidative stress can accumulate, and autophagic and mitophagic pathways can become overwhelmed. The imbalance of the delicate equilibrium among mitophagy, ROS production and mitochondrial damage can start, drive, or accelerate the aging process, either in physiological aging, or in pathological age-related conditions, such as Alzheimer’s and Parkinson’s diseases. It remains to be determined which is the prime mover of this imbalance, i.e., whether it is the mitochondrial damage caused by ROS that initiates the dysregulation of mitophagy, thus activating a vicious circle that leads to the reduced ability to remove damaged mitochondria, or an alteration in the regulation of mitophagy leading to the excessive production of ROS by damaged mitochondria.

MicroRNA Dysregulation in Parkinson's Disease: A Narrative Review

Parkinson’s disease (PD) is a severely debilitating neurodegenerative disease, affecting the motor system, leading to resting tremor, cogwheel rigidity, bradykinesia, walking and gait difficulties, and postural instability. The severe loss of dopaminergic neurons in the substantia nigra pars compacta causes striatal dopamine deficiency and the presence of Lewy bodies indicates a pathological hallmark of PD. Although the current treatment of PD aims to preserve dopaminergic neurons or to replace dopamine depletion in the brain, it is notable that complete recovery from the disease is yet to be achieved. Given the complexity and multisystem effects of PD, the underlying mechanisms of PD pathogenesis are yet to be elucidated. The advancement of medical technologies has given some insights in understanding the mechanism and potential treatment of PD with a special interest in the role of microRNAs (miRNAs) to unravel the pathophysiology of PD. In PD patients, it was found that striatal brain tissue and dopaminergic neurons from the substantia nigra demonstrated dysregulated miRNAs expression profiles. Hence, dysregulation of miRNAs may contribute to the pathogenesis of PD through modulation of PD-associated gene and protein expression. This review will discuss recent findings on PD-associated miRNAs dysregulation, from the regulation of PD-associated genes, dopaminergic neuron survival, α-synuclein-induced inflammation and circulating miRNAs. The next section of this review also provides an update on the potential uses of miRNAs as diagnostic biomarkers and therapeutic tools for PD.

miR-7b-3p Exerts a Dual Role After Spinal Cord Injury, by Supporting Plasticity and Neuroprotection at Cortical Level

Spinal cord injury (SCI) affects 6 million people worldwide with no available treatment. Despite research advances, the inherent poor regeneration potential of the central nervous system remains a major hurdle. Small RNAs (sRNAs) 19-33 nucleotides in length are a set of non-coding RNA molecules that regulate gene expression and have emerged as key players in regulating cellular events occurring after SCI. Here we profiled a class of sRNA known as microRNAs (miRNAs) following SCI in the cortex where the cell bodies of corticospinal motor neurons are located. We identified miR-7b-3p as a candidate target given its significant upregulation after SCI in vivo and we screened by miRWalk PTM the genes predicted to be targets of miR-7b-3p (among which we identified Wipf2, a gene regulating neurite extension). Moreover, 16 genes, involved in neural regeneration and potential miR-7b-3p targets, were found to be downregulated in the cortex following SCI. We also analysed miR-7b-3p function during cortical neuron development in vitro: we observed that the overexpression of miR-7b-3p was important (1) to maintain neurons in a more immature and, likely, plastic neuronal developmental phase and (2) to contrast the apoptotic pathway; however, in normal conditions it did not affect the Wipf2 expression. On the contrary, the overexpression of miR-7b-3p upon in vitro oxidative stress condition (mimicking the SCI environment) significantly reduced the expression level of Wipf2, as observed in vivo, confirming it as a direct miR-7b-3p target. Overall, these data suggest a dual role of miR-7b-3p: (i) the induction of a more plastic neuronal condition/phase, possibly at the expense of the axon growth, (ii) the neuroprotective role exerted through the inhibition of the apoptotic cascade. Increasing the miR-7b-3p levels in case of SCI could reactivate in adult neurons silenced developmental programmes, supporting at the same time the survival of the axotomised neurons.

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.

SOX21-AS1 modulates neuronal injury of MMP+-treated SH-SY5Y cells via targeting miR-7-5p and inhibiting IRS2

Parkinson's disease (PD), caused by the decreased number of dopaminergic neurons in the substantia nigra, is identified as the second most familiar age-dependent neurodegenerative disease to the public. Long non-coding RNAs (lncRNAs) have been reported to participate in the development of PD. In our research, the expression of lncRNA SRY-box transcription factor 21 antisense divergent transcript 1 (SOX21-AS1) was up-regulated in 1-methyl-4-phenylpyridinium (MMP⁺)-treated SH-SY5Y cells. In addition, SOX21-AS1 depletion weakened the cell injury induced by MMP⁺. Moreover, SOX21-AS1 knockdown decreased Reactive Oxygen Species (ROS) generation and levels of TNF-α, IL-1β and IL-6, but increased SOD activity. However, SOX21-AS1 up-regulation led to opposite results. Further, SOX21-AS1 could bind with miR-7-5p, whose overexpression relieved MMP⁺-induced cell injury. Additionally, insulin receptor substrate 2 (IRS2) served as the target gene of miR-7-5p, and its expression was positively modulated by SOX21-AS1. Similarly, IRS2 knockdown also had alleviative effects on cell injury stimulated by MMP⁺ treatment. In sum up, our study demonstrated a new regulatory network consisted of SOX21-AS1, miR-7-5p and IRS2 in SH-SY5Y cells, supplying with a better comprehension about the pathogenic mechanism of PD.

Novel Interplay between p53 and HO-1 in Embryonic Stem Cells

Stem cells genome safeguarding requires strict oxidative stress control. Heme oxygenase-1 (HO-1) and p53 are relevant components of the cellular defense system. p53 controls cellular response to multiple types of harmful stimulus, including oxidative stress. Otherwise, besides having a protective role, HO-1 is also involved in embryo development and in embryonic stem (ES) cells differentiation. Although both proteins have been extensively studied, little is known about their relationship in stem cells. The aim of this work is to explore HO-1-p53 interplay in ES cells. We studied HO-1 expression in p53 knockout (KO) ES cells and we found that they have higher HO-1 protein levels but similar HO-1 mRNA levels than the wild type (WT) ES cell line. Furthermore, cycloheximide treatment increased HO-1 abundance in p53 KO cells suggesting that p53 modulates HO-1 protein stability. Notably, H₂O₂ treatment did not induce HO-1 expression in p53 KO ES cells. Finally, SOD2 protein levels are also increased while Sod2 transcripts are not in KO cells, further suggesting that the p53 null phenotype is associated with a reinforcement of the antioxidant machinery. Our results demonstrate the existence of a connection between p53 and HO-1 in ES cells, highlighting the relationship between these stress defense pathways.

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.

Circulating RNAs as Potential Biomarkers in Amyotrophic Lateral Sclerosis

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

Knockdown of long non-coding RNA AL049437 mitigates MPP+ -induced neuronal injury in SH-SY5Y cells via the microRNA-205-5p/MAPK1 axis

BACKGROUND

Long noncoding RNAs (lncRNAs) have been defined as critical regulators of various human diseases. However, the functions of lncRNAs in Parkinson's disease (PD) have not yet been elucidated. In this study, we investigated the role of lncRNA AL049437 in PD and its underlying mechanism.

METHODS

An in vivo model of PD was established using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), while an in vitro model was created using N-methyl-4-phenylpyridinium (MPP+). Gene expression was evaluated using quantitative reverse transcriptase polymerase chain reaction and western blotting. The effects and mechanism of AL049437 in PD were explored using Cell Counting Kit-8 assay, flow cytometry, enzyme-linked immunosorbent assay, and 2',7'-dichlorodihydrofluorescein diacetate fluorescence assay. The interaction between AL049437, miR-205-5p, and mitogen-activated protein kinase 1 (MAPK1) was evaluated using luciferase reporter and RNA pull-down assays.

RESULTS

The expression of AL049437 was upregulated, while that of miR-205-5p was downregulated in MPTP-induced PD mouse model and MPP+-treated SH-SY5Y cells. Silencing of AL049437 mitigated MPP+-induced neurotoxicity in SH-SY5Y cells, as demonstrated by increased cell viability and reduced cell apoptosis. Furthermore, silencing of AL049437 alleviated MPP+-induced neuroinflammation and oxidative stress, as indicated by the reduction in tumor necrosis factor-α and interleukin-6 levels and reactive oxygen species production. In addition, AL049437 was predominantly localized in the cytoplasm of SH-SY5Y cells and functioned as an miR-205-5p sponge. Moreover, MAPK1 was identified as a downstream target of miR-205-5p. Remarkably, the impact of AL049437 silencing on MPP+-induced neuronal damage could be blocked by miR-205-5p inhibition or MAPK1 overexpression.

CONCLUSION

Knockdown of lncRNA AL049437 mitigates MPP+ -induced neuronal injury in SH-SY5Y cells by regulating the miR-205-5p/MAPK1 axis. Our research reveals a novel regulatory mechanism of AL049437 in PD progression.

SNHG1 promotes MPP+-induced cytotoxicity by regulating PTEN/AKT/mTOR signaling pathway in SH-SY5Y cells via sponging miR-153-3p

Background

Long non-coding RNA small molecule RNA host gene 1 (SNHG1) was previously identified to be relevant with Parkinson’s disease (PD) pathogenesis. This work aims to further elucidate the regulatory networks of SNHG1 involved in PD.

Methods

1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-hydrochloride (MPTP)-induced mice and 1-methyl-4-phenylpyridinium (MPP⁺)-treated SH-SY5Y cells were respectively constructed as the in vivo and in vitro PD models. Expression levels of SNHG1 and miR-153-3p were detected by qRT-PCR. Protein expression levels of phosphate and tension homology deleted on chromosome ten (PTEN) were measured by western blotting assay. Cell viability and apoptosis were determined by MTT and flow cytometry assays. The interactions among SNHG1, miR-153-3p and PTEN were identified by luciferase reporter assay, RNA immunoprecipitation, and/or RNA pull-down analysis.

Results

Increased SNHG1 expression was found in midbrain of MPTP-induced PD mice and MPP⁺-treated SH-SY5Y cells. Overexpression of SNHG1 lowered viability and enhanced apoptosis in MPP⁺-treated SH-SY5Y cells. Moreover, SNHG1 acted as a molecular sponge to inhibit the expression of miR-153-3p. Furthermore, miR-153-3p-mediated suppression of MPP⁺-induced cytotoxicity was abated following SNHG1 up-regulation. Additionally, PTEN was identified as a direct target of miR-153-3p, and SNHG1 could serve as a competing endogenous RNA (ceRNA) of miR-153-3p to improve the expression of PTEN. Besides, enforced expression of PTEN displayed the similar functions as SNHG1 overexpression in regulating the viability and apoptosis of MPP⁺-treated SH-SY5Y cells. Finally, SNHG1 was found to activate PTEN/AKT/mTOR signaling pathway in SH-SY5Y cells by targeting miR-153-3p.

Conclusion

SNHG1 aggravates MPP⁺-induced cellular toxicity in SH-SY5Y cells by regulating PTEN/AKT/mTOR signaling via sponging miR-153-3p, indicating the potential of SNHG1 as a promising therapeutic target for PD.

Glial HMOX1 expression promotes central and peripheral α-synuclein dysregulation and pathogenicity in parkinsonian mice

α-Synuclein is a key player in the pathogenesis of Parkinson disease (PD). Expression of human heme oxygenase-1 (HO-1) in astrocytes of GFAP.HMOX1 transgenic (TG) mice between 8.5 and 19 months of age results in a parkinsonian phenotype characterized by neural oxidative stress, nigrostriatal hypodopaminergia associated with locomotor incoordination, and overproduction of α-synuclein. We identified two microRNAs (miR-), miR-153 and miR-223, that negatively regulate α-synuclein in the basal ganglia of male and female GFAP.HMOX1 mice. Serum concentrations of both miRNAs progressively declined in the wild-type (WT) and GFAP.HMOX1 mice between 11 and 19 months of age. Moreover, at each time point surveyed, circulating levels of miR-153 were significantly lower in the TG animals compared to WT controls, while α-synuclein protein concentrations were elevated in erythrocytes of the GFAP.HMOX1 mice at 19 months of age relative to WT values. Primary WT neurons co-cultured with GFAP.HMOX1 astrocytes exhibited enhanced protein oxidation, mitophagy and apoptosis, aberrant expression of genes regulating the dopaminergic phenotype, and an imbalance in gene expression profiles governing mitochondrial fission and fusion. Many, but not all, of these neuronal abnormalities were abrogated by small interfering RNA (siRNA) knockdown of α-synuclein, implicating α-synuclein as a potent, albeit partial, mediator of HO-1's neurodystrophic effects in these parkinsonian mice. Overexpression of HO-1 in stressed astroglia has previously been documented in the substantia nigra of idiopathic PD and may promote α-synuclein production and toxicity by downmodulating miR-153 and/or miR-223 both within the CNS and in peripheral tissues.

MicroRNAs: Game Changers in the Regulation of α-Synuclein in Parkinson's Disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder. Its neuropathological hallmarks include neuronal loss in the substantia nigra pars compacta (SNpc) and the presence of Lewy bodies containing aggregates of α-synuclein (α-syn). An imbalance between the rates of α-syn synthesis, aggregation, and clearance can result in abnormal α-syn levels and contribute to the pathogenesis of PD. MicroRNAs (miRNAs) are endogenous single-stranded noncoding RNAs (∼22 nucleotides) that have recently emerged as key posttranscriptional regulators of gene expression. In this review, we summarize the functions of miRNAs that directly target α-syn. We also review miRNAs that indirectly impact α-syn levels or toxicity through different pathways, including those involved in the clearance of α-syn and neuroinflammation.

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

Parkinson's disease (PD), the second most prevalent age-related neurodegenerative disease, occurs as a result of the loss of dopaminergic neurons in the substantia nigra. Long non-coding RNA-p21 (lnc-p21) has been demonstrated to be upregulated in PD. However, its role in PD is unknown. Here, the results showed that lnc-p21 was highly expressed in human neuroblastoma SH-SY5Y cells treated with MPP⁺. Knockdown of lnc-p21 attenuated the cytotoxicity and cell apoptosis induced by MPP⁺ as shown by enhanced cell viability, decreased LDH release and cell apoptosis rate, accompanying with reduction of caspase-3 activity and Bax expression, and enhancement of Bcl-2 expression. Furthermore, knockdown of lnc-p21 mitigated MPP⁺-induced oxidative stress and neuroinflammation, as evidenced by the decrease in ROS generation, increase in SOD activity and decline in TNF-α, IL-1β and IL-6 levels. Conversely, overexpression of lnc-p21 resulted in the opposite effect. miR-625 was identified as a target of lnc-p21. lnc-p21 overturned the inhibitory effect of miR-625 on MPP⁺-induced neuronal injury in SH-SY5Y cells. Additionally, lnc-p21 positively regulated TRPM2 expression by targeting miR-625, and knockdown of TRPM2 inhibited MPP⁺-induced neuronal injury. Overall, our study identified a new lnc-p21-miR-625-TRPM2 regulatory network that lnc-p21 regulated MPP + -induced neuronal injury by sponging miR-625 and upregulating TRPM2 in SH-SY5Y cells, which provide a better understanding for the pathogenesis of PD.

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

The mammalian brain is made up of billions of neurons and supporting cells (glial cells), intricately connected. Molecular perturbations often lead to neurodegeneration by progressive loss of structure and malfunction of neurons, including their death. On the other side, a combination of genetic and cellular factors in glial cells, and less frequently in neurons, drive oncogenic transformation. In both situations, microenvironmental niches influence the progression of diseases and therapeutic responses. Dynamic changes that occur in cellular transcriptomes during the progression of developmental lineages and pathogenesis are controlled through a variety of regulatory networks. These include epigenetic modifications, signaling pathways, and transcriptional and post-transcriptional mechanisms. One prominent component of the latter is small non-coding RNAs, including microRNAs, that control the vast majority of these networks including genes regulating neural stemness, differentiation, apoptosis, projection fates, migration and many others. These cellular processes are also profoundly dependent on the microenvironment, stemness niche, hypoxic microenvironment, and interactions with associated cells including endothelial and immune cells. Significantly, the brain of all other mammalian organs expresses the highest number of microRNAs, with an additional gain in expression in the early stage of neurodegeneration and loss in expression in oncogenesis. However, a mechanistic explanation of the concept of an apparent inverse correlation between the odds of cancer and neurodegenerative diseases is only weakly developed. In this review, we thus will discuss widespread de-regulation of microRNAome observed in these two major groups of brain pathologies. The deciphering of these intricacies is of importance, as therapeutic restoration of pre-pathological microRNA landscape in neurodegeneration must not lead to oncogenesis and vice versa. We thus focus on microRNAs engaged in cellular processes that are inversely regulated in these diseases. We also aim to define the difference in microRNA networks between pro-survival and pro-apoptotic signaling in the brain.

Upregulated lncRNA small nucleolar RNA host gene 1 promotes 1-methyl-4-phenylpyridinium ion-induced cytotoxicity and reactive oxygen species production through miR-15b-5p/GSK3β axis in human dopaminergic SH-SY5Y cells

Long noncoding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) has been demonstrated to be upregulated and play a crucial role in the pathology of Parkinson's disease (PD). However, the exact role of SNHG1 and its underlying mechanisms in PD remains elusive. In this study, we found that SNHG1 and glycogen synthase kinase 3 beta (GSK3β) were upregulated, but miR-15b-5p was downregulated in 1-methyl-4-phenylpyridinium ion (MPP⁺ )-treated SH-SY5Y cells. The upregulation of SNHG1 enhanced MPP⁺ -induced cellular toxicity in SH-SY5Y cells, as shown by decreased cell viability, increased ROS production, and increased number of TdT-mediated dUTP Nick-End labeling-positive cells, accompanied with the upregulation of cleaved caspase 3 and elevation of cytochrome C release. Meanwhile, SNHG1 knockdown presented the converse effects. SNHG1 was demonstrated to interact with miR-15b-5p. Moreover, SNHG1 could attenuate the inhibitory effects of miR-15b-5p on MPP⁺ -induced cytotoxicity and production of ROS. Besides, GSK3β was identified as a direct target of miR-15b-5p. The inhibitory effects of SNHG1 knockdown or miR-15b-5p overexpression on MPP⁺ -induced cytotoxicity and reactive oxygen species (ROS) production were abrogated by upregulation of GSK3β. Taken together, these results demonstrate that upregulated lncRNA SNHG1 promotes MPP⁺ -induced cytotoxicity and ROS production through the miR-15b-5p/GSK3β axis in human dopaminergic SH-SY5Y cells, suggesting that SNHG1 may act as a potential therapeutic target for PD treatment in the future.

The Role of miRNA-132 against Apoptosis and Oxidative Stress in Heart Failure

OBJECTIVE

To explore the effect of microRNA-132 of heart failure and provide theoretical guidance for clinical treatment of heart failure (HF).

METHODS

Peripheral blood was collected from HF patients. RT-qPCR was used to determine microRNA-132 expression. Mouse models of heart failure were established. Color Doppler ultrasound was utilized to measure the changes of cardiac function. HE and Masson staining were applied to observe pathological changes of the myocardium. After H9C2 cells were transfected with microRNA-132, MTT assay was employed to detect the stability of H9C2 cells. ELISA was used to measure the levels of oxidative stress factors. Western blot assay and RT-qPCR were utilized to determine the expression of Bax, Bcl-2, TGF-β1, and smad3.

RESULTS

MicroRNA-132 expression was downregulated in HF patients' blood. After establishing mouse models of HF, cardiac function obviously decreased. HE staining revealed the obvious edema and hypertrophy of cardiomyocytes. Masson staining demonstrated that cardiomyocytes were markedly fibrotic. After microRNA-132 transfection and H9C2 cell apoptosis induced by H2O2, antioxidant stress and antiapoptotic ability of the H9C2 cells obviously increased. TGF-β1 and smad3 expression remarkably diminished.

CONCLUSION

Overexpression of microRNA-132 dramatically increased the antioxidant stress and antiapoptotic ability of H9C2 cells and decreased the expression of TGF-β1 and smad3.