Upregulation of miR-200a and miR-204 in MPP+ -treated differentiated PC12 cells as a model of Parkinson's disease

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.

miR-193b-3p/ PGC-1α pathway regulates an insulin dependent anti-inflammatory response in Parkinson's disease

It has been shown that many miRNAs, including miR-193b-3p, are differentially expressed in Parkinson's disease (PD). Dysregulation of miR-193b-3p/PGC-1α axis may alter homeostasis in cells and can induce an inflammatory response commonly accompanied by metabolic disturbances. The aim of the present study is to investigate if dysregulation of the miR-193-3p/PGC-1α axis may contribute to the pathological changes observed in the PD brain. Brain tissue were obtained from middle frontal gyrus of non-demented controls and individuals with a PD diagnosis. RT-qPCR was used to determine the expression of miR-193b-3p and in situ hybridization (ISH) and immunological analysis were employed to establish the cellular distribution of miR-193b-3p. Functional assays were performed using SH-SY5Y cells, including transfection and knock-down of miR-193b-3p. We found significantly lower expression of miR-193b-3p in the early stages of PD (PD4) which increased throughout disease progression. Furthermore, altered expression of PGC-1α suggested a direct inhibitory effect of miR-193b-3p in the brain of individuals with PD. Moreover, we observed changes in expression of insulin after transfection of SH-SY5Y cells with miR-193b-3p, which led to dysregulation in the expression of several pro- or anti - inflammatory genes. Our findings indicate that the miR-193b-3p/PGC-1α axis is involved in the regulation of insulin signaling. This regulation is crucial, since insulin induced inflammatory response may serve as a protective mechanism during acute situations but potentially evolve into a pathological process in chronic conditions. This novel regulatory mechanism may represent an interesting therapeutic target with potential benefits for various neurodegenerative diseases.

Mechanistic Evaluation of miRNAs and Their Targeted Genes in the Pathogenesis and Therapeutics of Parkinson's Disease

MicroRNA (miRNA) are usually 18-25 nucleotides long non-coding RNA targeting post-transcriptional regulation of genes involved in various biological processes. The function of miRNA is essential for maintaining a homeostatic cellular condition, regulating autophagy, cellular motility, and inflammation. Dysregulation of miRNA is responsible for multiple disorders, including neurodegeneration, which has emerged as a severe problem in recent times and has verified itself as a life-threatening condition that can be understood by the continuous destruction of neurons affecting various cognitive and motor functions. Parkinson's disease (PD) is the second most common, permanently debilitating neurodegenerative disorder after Alzheimer's, mainly characterized by uncontrolled tremor, stiffness, bradykinesia or akinesia (slowness in movement), and post-traumatic stress disorder. PD is mainly caused by the demolition of the primary dopamine neurotransmitter secretory cells and dopaminergic or dopamine secretory neurons in the substantia nigra pars compacta of the midbrain, which are majorly responsible for motor functions. In this study, a systematic evaluation of research articles from year 2017 to 2022 was performed on multiple search engines, and lists of miRNA being dysregulated in PD in different body components were generated. This study highlighted miR-7, miR-124, miR-29 family, and miR-425, showing altered expression levels during PD's progression, further regulating the expression of multiple genes responsible for PD.

The Potential of Targeting Autophagy-Related Non-coding RNAs in the Treatment of Alzheimer's and Parkinson's Diseases

Clearance of accumulated protein aggregates is one of the functions of autophagy. Recently, a clearer understanding of non-coding RNAs (ncRNAs) functions documented that ncRNAs have important roles in several biological processes associated with the development and progression of neurodegenerative disorders. Subtypes of ncRNA, including microRNA (miRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA), are commonly dysregulated in neurodegenerative disorders such as Alzheimer and Parkinson diseases. Dysregulation of these non-coding RNAs has been associated with inhibition or stimulation of autophagy. Decreased miR-124 led to decreased/increased autophagy in experimental model of Alzheimer and Parkinson diseases. Increased BACE1-AS showed enhanced autophagy in Alzheimer disease by targeting miR-214-3p, Beclin-1, LC3-I/LC3-II, p62, and ATG5. A significant increase in NEAT1led to stimulated autophagy in experimental model of PD by targeting PINK1, LC3-I, LC3-II, p62 and miR-374c-5p. In addition, increased BDNF-AS and SNHG1 decreased autophagy in MPTP-induced PD by targeting miR-125b-5p and miR-221/222, respectively. The upregulation of circNF1-419 and circSAMD4A resulted in an increased autophagy by regulating Dynamin-1 and miR-29c 3p, respectively. A detailed discussion of miRNAs, circRNAs, and lncRNAs in relation to their autophagy-related signaling pathways is presented in this study.

The SH-SY5Y cell line: a valuable tool for Parkinson's disease drug discovery

INTRODUCTION

Owing to limited efficient treatment strategies for highly prevalent and distressing Parkinson's disease (PD), an impending need emerged for deciphering new modes and mechanisms for effective management. SH-SY5Y-based in vitro neuronal models have emerged as a new possibility for the elucidation of cellular and molecular processes in the pathogenesis of PD. SH-SY5Y cells are of human origin, adhered to catecholaminergic neuronal attributes, which consequences in imparting wide acceptance and significance to this model over conventional in vitro PD models for high-throughput screening of therapeutics.

AREAS COVERED

Herein, the authors review the SH-SY5Y cell line and its value to PD research. The authors also provide the reader with their expert perspectives on how these developments can lead to the development of new impactful therapeutics.

EXPERT OPINION

Encouraged by recent research on SH-SY5Y cell lines, it was envisaged that this in vitro model can serve as a primary model for assessing efficacy and toxicity of new therapeutics as well as for nanocarriers' capacity in delivering therapeutic agents across BBB. Considering the proximity with human neuronal environment as in pathogenic PD conditions, SH-SY5Y cell lines vindicated consistency and reproducibility in experimental results. Accordingly, exploitation of this standardized SH-SY5Y cell line can fast-track the drug discovery and development path for novel therapeutics.

The Construction and Validation of a Novel Ferroptosis-Related Gene Signature in Parkinson's Disease

As a newly discovered regulated cell death mode, ferroptosis is associated with the development of Parkinson's disease (PD) and has attracted much attention. Nonetheless, the relationship between ferroptosis and PD pathogenesis remains unclear. The GSE8397 dataset includes GPL96 and GPL97 platforms. The differential genes were analyzed by immune infiltration and Gene Set Enrichment Analysis (GSEA) (p < 0.05), and differential multiple |logFC| > 1 and weighted gene coexpression network analysis (WGCNA) were used to screen differential expression genes (DEGs). The intersection with 368 ferroptosis-related genes (FRGs) was conducted for gene ontology/Kyoto encyclopedia of gene and genome (GO/KEGG) enrichment analysis, gene expression analysis, correlation analysis, single-cell sequencing analysis, and prognosis analysis (area under the curve, AUC) and to predict relevant miRNAs and construct network diagrams using Cytoscape. The intersection genes of differentially expressed ferroptosis-related genes (DEFRGs) and mitochondrial dysfunction genes were validated in the substantia nigra of MPTP-induced PD mice models by Western blotting and immunohistochemistry, and the protein-binding pocket was predicted using the DoGSiteScorer database. According to the results, the estimated scores were positively correlated with the stromal scores or immune scores in the GPL96 and GPL97 platforms. In the GPL96 platform, the GSEA showed that differential genes were mainly involved in the GnRH signaling pathway, B cell receptor signaling pathway, inositol phosphate metabolism, etc. In the GPL97 platform, the GSEA showed that differential genes were mainly involved in the ubiquitin-mediated proteolysis, axon guidance, Wnt signaling pathway, MAPK signaling pathway, etc. We obtained 26 DEFRGs, including 12 up-regulated genes and 14 down-regulated genes, with good correlation. The area under the prognostic analysis curve (AUC > 0.700) showed a good prognostic ability. We found that they were enriched in different neuronal cells, oligodendrocytes, astrocytes, oligodendrocyte precursor cells, and microglial cells, and their expression scores were positively correlated, and selected genes with an AUC curve ≥0.9 were used to predict miRNA, including miR-214/761/3619-5p, miR-203, miR-204/204b/211, miR-128/128ab, miR-199ab-5p, etc. For the differentially expressed ferroptosis-mitochondrial dysfunction-related genes (DEF-MDRGs) (AR, ISCU, SNCA, and PDK4), in the substantia nigra of mice, compared with the Saline group, the expression of AR and ISCU was decreased (p < 0.05), and the expression of α-Syn and PDK4 was increased (p < 0.05) in the MPTP group. Therapeutic drugs that target SNCA include ABBV-0805, Prasinezumab, Cinpanemab, and Gardenin A. The results of this study suggest that cellular DEF-MDRGs might play an important role in PD. AR, ISCU, SNCA, and PDK4 have the potential to be specific biomarkers for the early diagnosis of PD.

Gentisic acid ameliorates type 2 diabetes induced by Nicotinamide-Streptozotocin in male mice by attenuating pancreatic oxidative stress and inflammation through modulation of Nrf2 and NF-кB pathways

AIMS

There is a close link between oxidative stress, inflammation, and type 2 diabetes mellitus (T2DM). Gentisic acid (GA) is a di-phenolic compound and an active metabolite of aspirin that possesses antioxidant and anti-inflammatory properties, but its potential anti-diabetic effects have not been evaluated so far. Therefore, this study aimed to evaluate GA's potential antidiabetic effects through the Nuclear Factor Erythroid 2-Related Factor (Nrf2) and Nuclear Factor Kappa Beta (NF-кB) signaling pathways.

MATERIAL AND METHODS

In this study, T2DM induced by a single intraperitoneal injection of STZ (65 mg/kg B.W) after 15 min nicotinamide (120 mg/kg B.W) injection. After seven days of injections, fasting blood glucose (FBS) was measured. Seven days after FBS monitoring treatments started. Grouping and treatments were as follows: 1) Normal control group; NC, 2) Diabetic control group; DC, 3) Metformin group; MT (150 mg/kg B.W, daily), 4) Test group; GA (100 mg/kg B.W, daily). Treatments continued for 14 consecutive days.

KEY FINDINGS

Diabetic mice treatment with GA significantly decreased FBS, improved plasma lipid profiles and pancreatic antioxidant status. GA modulated Nrf2 pathway by upregulation of Nrf2 protein, NAD(P)H: quinone oxidoreductase 1 (Nqo1), and p21, and downregulation of miR-200a, Kelch-like ECH-associated protein 1 (Keap1), and nicotinamide adenine dinucleotide phosphate oxidase-2 (NOX2). Also, GA attenuated inflammation by upregulation of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and interleukin-10 (IL-10) and downregulation of miR-125b, NF-кB, tumor necrosis factor-alpha (TNF-α), and interleukin-1 beta (IL-1ß).

SIGNIFICANCE

GA attenuates T2DM, possibly by improving antioxidant status through the Nrf2 pathway and attenuation of inflammation.

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

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

Small noncoding RNA dysregulation is implicated in manganism in a rat model of methylcyclopentadienyl manganese tricarbonyl-induced unrepaired striatum damage

The accumulation of excessively high manganese levels within the brain can contribute to a series of Parkinsonian symptoms referred to as manganism. The gasoline antiknock additive Methylcyclopentadienyl Manganese Tricarbonyl (MMT) is an environmental source of manganese exposure and can induce manganism in rats. While some prior reports have demonstrated the differential expression of small noncoding RNAs (sncRNAs) in patients with Parkinson's disease (PD), the degree of sncRNA dysfunction in manganism has yet to be clearly documented. As sncRNAs such as transfer RNA-derived small RNAs (tsRNAs) and ribosomal RNA-derived small RNAs (rsRNAs) exhibit high levels of modifications such as 3' terminal 3'-phosphate and 2',3'-cyclic phosphate modifications that disrupt the process of adapter ligation and m1A, m3C, m1G, and m22G RNA methylation, these transcripts are not detected in traditional small RNA-sequencing studies. Here, differential sncRNA expression was analyzed by comparing a rat model of MMT-induced unrepaired striatum damage to appropriate control samples via PANDORA-Seq, which can detect highly modified sncRNAs. Following the removal of sncRNA modifications, this approach identified 599 sncRNAs that were differentially expressed in the striatum of MMT-exposed rats relative to controls, as well as 1155 sncRNAs that were differentially expressed in Mn-treated and control rats. Additional functional analyses were performed to predict the putative targets of these sncRNAs, implicating a role for such sncRNA dysregulation in the pathogenesis of manganism in this rat model system.

Lmx1a-Dependent Activation of miR-204/211 Controls the Timing of Nurr1-Mediated Dopaminergic Differentiation

The development of midbrain dopaminergic (DA) neurons requires a fine temporal and spatial regulation of a very specific gene expression program. Here, we report that during mouse brain development, the microRNA (miR-) 204/211 is present at a high level in a subset of DA precursors expressing the transcription factor Lmx1a, an early determinant for DA-commitment, but not in more mature neurons expressing Th or Pitx3. By combining different in vitro model systems of DA differentiation, we show that the levels of Lmx1a influence the expression of miR-204/211. Using published transcriptomic data, we found a significant enrichment of miR-204/211 target genes in midbrain dopaminergic neurons where Lmx1a was selectively deleted at embryonic stages. We further demonstrated that miR-204/211 controls the timing of the DA differentiation by directly downregulating the expression of Nurr1, a late DA differentiation master gene. Thus, our data indicate the Lmx1a-miR-204/211-Nurr1 axis as a key component in the cascade of events that ultimately lead to mature midbrain dopaminergic neurons differentiation and point to miR-204/211 as the molecular switch regulating the timing of Nurr1 expression.

Revisiting the miR-200 Family: A Clan of Five Siblings with Essential Roles in Development and Disease

Over two decades of studies on small noncoding RNA molecules illustrate the significance of microRNAs (miRNAs/miRs) in controlling multiple physiological and pathological functions through post-transcriptional and spatiotemporal gene expression. Among the plethora of miRs that are essential during animal embryonic development, in this review, we elaborate the indispensable role of the miR-200 family (comprising miR-200a, -200b, 200c, -141, and -429) in governing the cellular functions associated with epithelial homeostasis, such as epithelial differentiation and neurogenesis. Additionally, in pathological contexts, miR-200 family members are primarily involved in tumor-suppressive roles, including the reversal of the cancer-associated epithelial–mesenchymal transition dedifferentiation process, and are dysregulated during organ fibrosis. Moreover, recent eminent studies have elucidated the crucial roles of miR-200s in the pathophysiology of multiple neurodegenerative diseases and tissue fibrosis. Lastly, we summarize the key studies that have recognized the potential use of miR-200 members as biomarkers for the diagnosis and prognosis of cancers, elaborating the application of these small biomolecules in aiding early cancer detection and intervention.

Deregulated mitochondrial microRNAs in Alzheimer's disease: Focus on synapse and mitochondria

Alzheimer's disease (AD) is the most common cause of dementia and is currently one of the biggest public health concerns in the world. Mitochondrial dysfunction in neurons is one of the major hallmarks of AD. Emerging evidence suggests that mitochondrial miRNAs potentially play important roles in the mitochondrial dysfunctions, focusing on synapse in AD progression. In this meta-analysis paper, a comprehensive literature review was conducted to identify and discuss the (1) role of mitochondrial miRNAs that regulate mitochondrial and synaptic functions; (2) the role of various factors such as mitochondrial dynamics, biogenesis, calcium signaling, biological sex, and aging on synapse and mitochondrial function; (3) how synapse damage and mitochondrial dysfunctions contribute to AD; (4) the structure and function of synapse and mitochondria in the disease process; (5) latest research developments in synapse and mitochondria in healthy and disease states; and (6) therapeutic strategies that improve synaptic and mitochondrial functions in AD. Specifically, we discussed how differences in the expression of mitochondrial miRNAs affect ATP production, oxidative stress, mitophagy, bioenergetics, mitochondrial dynamics, synaptic activity, synaptic plasticity, neurotransmission, and synaptotoxicity in neurons observed during AD. However, more research is needed to confirm the locations and roles of individual mitochondrial miRNAs in the development of AD.

Thioredoxin-1 Rescues MPP+/MPTP-Induced Ferroptosis by Increasing Glutathione Peroxidase 4

Parkinson's disease (PD), a common neurodegenerative disease, is typically associated with the loss of dopaminergic neuron in the substantia nigra pars compacta (SNpc). Ferroptosis is a newly identified cell death, which associated with iron accumulation, glutathione (GSH) depletion, lipid peroxidation formation, reactive oxygen species (ROS) accumulation, and glutathione peroxidase 4 (GPX4) reduction. It has been reported that ferroptosis is linked with PD.Thioredoxin-1 (Trx-1) is a redox regulating protein and plays various roles in regulating the activity of transcription factors and inhibiting apoptosis. However, whether Trx-1 plays the role in regulating ferroptosis involved in PD is still unknown. Our present study showed that 1-methyl-4-phenylpyridinium (MPP+) decreased cell viability, GPX4, and Trx-1, which were reversed by Ferrostatin-1 (Fer-1) in PC 12 cells and SH-SY5Y cells. Moreover, the decreased GPX4 and GSH, and increased ROS were inhibited by Fer-1 and Trx-1 overexpression. We further repeated that behavior deficits resulted from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were improved in Trx-1 overexpression transgenic mice. Trx-1 reversed the decreases of GPX4 and tyrosine hydroxylase (TH) induced by MPTP in the substantia nigra pars compacta (SNpc). Our results suggest that Trx-1 inhibits ferroptosis in PD through regulating GPX4 and GSH.

MiR-141-3p and miR-200a-3p are involved in Th17 cell differentiation by negatively regulating RARB expression

Among T helper (Th) lineages differentiated from naïve CD4⁺ T cells, interleukin (IL)-17-producing Th17 cells are highly correlated with the pathogenesis of autoimmune disorders. This study aimed to clarify the involvement of miR-141-3p and miR-200a-3p in Th17 cell differentiation as well as explore their potential target genes involved. For this purpose, human naïve CD4⁺ T cells were cultured under Th17 cell polarizing condition. The differentiation process was confirmed through measurement of IL-17 secretion using the ELISA method and assessment of Th17 cell-defining genes expression during the differentiation period. MiR-141-3p and miR-200a-3p downstream genes were identified via consensus and integration in silico approach and their expression pattern and alterations were evaluated by quantitative real-time PCR. Finally, direct interaction between both microRNAs (miRNAs) and their common predicted target sequences was approved by dual-luciferase reporter assay. Highly increased IL-17 secretion and Th17 lineage-specific genes expression confirmed Th17 cell differentiation. Our results have demonstrated that miR-141-3p and miR-200a-3p are Th17 cell-associated miRNAs and their expression level is upregulated significantly during Th17 cell induction. We have also found that retinoic acid receptor beta (RARB) gene, whose product has been reported as a negative regulator of Th17 cell generation, is a direct target of both miRNAs and its downregulation can affect the transcriptional level of JAK/STAT pathway genes. Overall, our results have identified two novel Th17 lineage-associated miRNAs and have provided evidence for the RARB-dependent mechanism of miR-141-3p and miR-200a-3p-induced Th17 cell differentiation and hence Th17-mediated autoimmunity.

MiR-193b deregulation is associated with Parkinson's disease

PGC-1α/FNDC5/BDNF has found to be a critical pathway in neurodegeneration. MicroRNAs (miR(NA)s) are non-coding regulatory RNAs whose dysregulation has been observed in multiple neurological disorders, and miRNA-mediated gene deregulation plays a decisive role in PD. Here, candidate miRNA was chosen based on the literature survey and in silico studies. Chronic and acute models of PD were created using MPP+-treated SH-SY5Y cells. Twenty PD patients and 20 healthy volunteers were recruited. RT-qPCR was performed to assess the expression of miRNA and genes. Severe mitochondrial dysfunction induced by acute MPP+ treatment instigated compensatory mechanisms through enhancing expression of PGC-1α/FNDC5/BDNF pathway genes, while chronic MPP+ toxicity led to down-regulated levels of the genes in SH-SY5Y cells. PD peripheral blood mononuclear cells (PBMCs) also showed decreased expression of target genes. There were significant changes in the level of miR-193b in both models, as well as PD PBMCs. Moreover, miR-193b overexpression significantly affected PGC-1α, FNDC5 and TFAM levels. Interestingly, down-regulations of PGC-1α, FNDC5, BDNF and TFAM were inversely correlated with miR-193b up-regulation in PD PBMCs. This study showed the deregulation of PGC-1α/FNDC5/BDNF pathway in PD models and PBMCs, verifying its importance in neurodegeneration. Our findings also revealed that miR-193b functions in PD development, possibly through regulating PGC-1α/FNDC5/BDNF pathway, suggesting miR-193b as a potential biomarker for PD diagnosis.

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.

MicroRNAs, Parkinson's Disease, and Diabetes Mellitus

Parkinson’s disease (PD) is a neurodegenerative disorder that affects 1% of the population over the age of 60. Diabetes Mellitus (DM) is a metabolic disorder that affects approximately 25% of adults over the age of 60. Recent studies showed that DM increases the risk of developing PD. The link between DM and PD has been discussed in the literature in relation to different mechanisms including mitochondrial dysfunction, oxidative stress, and protein aggregation. In this paper, we review the common microRNA (miRNA) biomarkers of both diseases. miRNAs play an important role in cell differentiation, development, the regulation of the cell cycle, and apoptosis. They are also involved in the pathology of many diseases. miRNAs can mediate the insulin pathway and glucose absorption. miRNAs can also regulate PD-related genes. Therefore, exploring the common miRNA biomarkers of both PD and DM can shed a light on how these two diseases are correlated, and targeting miRNAs is a potential therapeutic opportunity for both diseases.

Mir-141-3p Regulates Apoptosis and Mitochondrial Membrane Potential via Targeting Sirtuin1 in a 1-Methyl-4-Phenylpyridinium in vitro Model of Parkinson's Disease

Objectives

Parkinson's disease (PD) is a common neurodegenerative disease characterized by the loss of midbrain dopaminergic neurons in the substantia nigra. The present study investigated miR-141-3p/sirtuin1 (SIRT1) activity in a 1-methyl-4-phenylpyridinium- (MPP+-) induced PC12-cell model of PD.

Methods

PC12 cells were exposed to MMP+ following induction of differentiation by nerve growth factor (NGF). miR-141-3p and SIRT1 expressions were examined using RT-qPCR and western blot. Cell viability was evaluated using the MTT assay. Apoptosis percentage, reactive oxygen species (ROS) production, and mitochondrial membrane potential (Δψm) were evaluated using flow cytometry. Expression of Nuclear factor-kappa B- (NF-κB-) related proteins was determined by western blot. Bioinformatic analysis, RT-qPCR, and luciferase reporter assay were used to confirm the interaction between miR-141-3p and SIRT1.

Results

miR-141-3p was upregulated, and SIRT1 was downregulated in MPP+-treated PC12 cells. MPP+ treatment also upregulated nitric oxide synthase 1 (Nos1) and α-synuclein. miR-141-3p induced apoptosis, oxidative stress, mitochondrial dysfunction, and downregulated the SIRT1 mRNA expression. The luciferase reporter assay showed that SIRT1 was the target of miR-141-3p. SIRT1 transfection attenuated apoptosis, ROS production and maintained Δψm. SIRT1 also downregulated Nos1, tumor necrosis factor-α (TNF-α), interleukin 1 beta (IL-1β), interleukin 6(IL-6) and upregulated B cell lymphoma 2 (Bcl-2) protein. In addition, SIRT1 activator resveratrol blocked the effects of miR-141-3p mimic on Nos1, α-synuclein, and mitochondrial membrane potential. SIRT1 inhibitor sirtinol reversed the biological effects of miR-141-3p.

Conclusion

Increased miR-141-3p induced apoptosis, oxidative stress, and mitochondrial dysfunction in MPP+-treated PC12 cells by directly targeting the SIRT1 expression. Our study provided a potential therapeutic strategy for PD.

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

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

DNA three-way junction-actuated strand displacement for miRNA detection using a fluorescence light-up Ag nanocluster probe

A rapid and label-free fluorescence biosensing strategy for highly sensitive detection of microRNA-122 (miR-122) has been developed by the combination of DNA three-way junction (TWJ)-actuated strand displacement and a fluorescence light-up Ag nanocluster (AgNC) probe. In the presence of target miR-122, the attachment of miR-122 to its complementary DNA results in the unblocking of the toehold and branch migration domains in the TWJ, activating the strand displacement reaction (SDR) accompanied by the proximity between the G-rich DNA probe and DNA-AgNC probe; thus a remarkably enhanced fluorescence signal of AgNCs can be obtained owing to the G-rich fluorescence enhancement mechanism. The results reveal that this biosensor exhibits superb specificity and high sensitivity toward miR-122 with a detection limit of 0.030 nM. In addition, the practicality of the biosensor is demonstrated by analyzing miR-122 in three cell lines with satisfactory results. Furthermore, by the utilization of the toehold-mediated SDR and DNA-AgNC conjugates, this proposed strategy offers the advantages of rapidness, convenience, low cost, and simplified operation without the need for biological labeling and the addition of enzymes. Thus, the constructed biosensor might provide a valuable and practical tool for detecting miRNA and the related clinical diagnosis and fundamental biomedicine research.

Upregulation of miR-200a and miR-204 in MPP+ -treated differentiated PC12 cells as a model of Parkinson's disease

Background

Parkinson's disease (PD) is ranked as the second most common neurodegenerative disorder caused by loss of dopaminergic neurons in the substantia nigra. Micro(mi)RNAs are a class of small noncoding RNAs that regulate gene expression and aberrant expression of them is closely correlated with many neurodegenerative conditions including PD. Silent information regulator 1 (SIRT1) as a known deacetylase and B‐cell lymphoma‐2 (BCL2) as an antiapoptotic factor play vital roles in neural protection and survival.

Methods

Differentiated PC12 cells exposed to MPP⁺ were served here as a known PD model. Cell viability was determined by MTS assay. Apoptotic cells and ROS levels were detected using flow cytometry. Gene selection and miRNA–mRNA interaction analysis were performed through in silico methods. Relative expression of miRNAs and genes was examined by RT‐qPCR.

Results

MPP⁺ exposure markedly reduced cell viability, enhanced oxidative stress, and induced apoptosis in differentiated PC12 cells. Sirt1 and BCL2were shown to be markedly declined in response to MPP⁺, while miR‐200a and miR‐204 were significantly upregulated.

Conclusion

The first novel finding of the current study is altered expression of miR‐200a and miR‐204 in differentiated PC12 cells in response to MPP⁺, suggesting that deregulation of them participate in MPP⁺ neurotoxicity mechanisms, possibly via affecting the expression of Sirt1 and BCL2 as potential targets.