Suppression of lncRNA-ATB prevents amyloid-β-induced neurotoxicity in PC12 cells via regulating miR-200/ZNF217 axis

Hsa_circ_0049472 contributed to amyloid-beta peptide-induced neurotoxicity, apoptosis and inflammation via regulating PI3K-AKT signaling pathway by interacting with miR-22-3p/ZNF217 axis

BACKGROUND

Circular RNAs (circRNAs) exhibited important roles in Alzheimer's disease (AD). Here, we focused on the dysregulation of hsa_circ_0049472 (circ_0049472) and potential functions in SK-N-SH cells with amyloid-beta peptide (Aβ) treatment in AD.

METHODS

RNA expression was detected by real-time quantitative PCR. Cell viability and proliferation were measured by MTS and Edu assays. Flow cytometry was used for apoptosis detection, and cell inflammation was assessed using enzyme-linked immunosorbent assay. Target interaction was validated by dual-luciferase reporter assay and RNA immunoprecipitation assay. Protein expression and phosphatidylinositol 3-kinase-protein kinase B (PI3K-AKT) pathway were examined by Immunoblotting.

RESULTS

Aβ treatment inhibited cell viability and proliferation of SK-N-SH cells, but enhanced apoptosis rate, apoptosis protein levels (Bcl2-associated X protein and cleaved-caspase-3) and inflammatory cytokines (interleukin -6, IL-1β, tumor necrosis factor-α). Then, circ_0049472 expression was shown to be upregulated in response to Aβ stimulation and knockdown of circ_0049472 has ameliorated Aβ-induced cell injury. Circ_0049472 was identified as a sponge for miR-22-3p, and miR-22-3p inhibition reversed the regulation of circ_0049472 knockdown in Aβ-treated cells. Furthermore, ZNF217 acted as a target of miR-22-3p and circ_0049472 could regulate ZNF217 expression via binding to miR-22-3p. Overexpression of miR-22-3p abated Aβ-induced apoptosis and inflammation via downregulating ZNF217. Furthermore, Aβ reduced proteins levels of p-PI3K and p-AKT, and this inhibition of PI3K-AKT pathway was restored by the regulation of circ_0049472/miR-22-3p/ZNF217 axis.

CONCLUSION

Circ_0049472 was involved in Aβ-induced neural injury by regulating miR-22-3p/ZNF217 axis to affect PI3K-AKT pathway. This study has discovered an innovative mechanism for AD.

Hidden regulators: the emerging roles of lncRNAs in brain development and disease

Long non-coding RNAs (lncRNAs) have emerged as critical players in brain development and disease. These non-coding transcripts, which once considered as "transcriptional junk," are now known for their regulatory roles in gene expression. In brain development, lncRNAs participate in many processes, including neurogenesis, neuronal differentiation, and synaptogenesis. They employ their effect through a wide variety of transcriptional and post-transcriptional regulatory mechanisms through interactions with chromatin modifiers, transcription factors, and other regulatory molecules. Dysregulation of lncRNAs has been associated with certain brain diseases, including Alzheimer's disease, Parkinson's disease, cancer, and neurodevelopmental disorders. Altered expression and function of specific lncRNAs have been implicated with disrupted neuronal connectivity, impaired synaptic plasticity, and aberrant gene expression pattern, highlighting the functional importance of this subclass of brain-enriched RNAs. Moreover, lncRNAs have been identified as potential biomarkers and therapeutic targets for neurological diseases. Here, we give a comprehensive review of the existing knowledge of lncRNAs. Our aim is to provide a better understanding of the diversity of lncRNA structure and functions in brain development and disease. This holds promise for unravelling the complexity of neurodevelopmental and neurodegenerative disorders, paving the way for the development of novel biomarkers and therapeutic targets for improved diagnosis and treatment.

NcRNAs: A synergistically antiapoptosis therapeutic tool in Alzheimer's disease

AIMS

The aim of this review is to systematically summarize and analyze the noncoding RNAs (ncRNAs), especially microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), in the cell apoptosis among Alzheimer's disease (AD) in recent years to demonstrate their value in the diagnosis and treatment of AD.

METHODS

We systematically summarized in vitro and in vivo studies focusing on the ncRNAs in the regulation of cell apoptosis among AD in PubMed, ScienceDirect, and Google Scholar.

RESULTS

We discover three patterns of ncRNAs (including 'miRNA-mRNA', 'lncRNA-miRNA-mRNA', and 'circRNA-miRNA-mRNA') form the ncRNA-based regulatory networks in regulating cell apoptosis in AD.

CONCLUSIONS

This review provides a future diagnosis and treatment strategy for AD patients based on ncRNAs.

Alzheimer's Disease-Related Epigenetic Changes: Novel Therapeutic Targets

Aging is a significant risk factor for Alzheimer's disease (AD), although the precise mechanism and molecular basis of AD are not yet fully understood. Epigenetic mechanisms, such as DNA methylation and hydroxymethylation, mitochondrial DNA methylation, histone modifications, and non-coding RNAs (ncRNAs), play a role in regulating gene expression related to neuron plasticity and integrity, which are closely associated with learning and memory development. This review describes the impact of dynamic and reversible epigenetic modifications and factors on memory and plasticity throughout life, emphasizing their potential as target for therapeutic intervention in AD. Additionally, we present insight from postmortem and animal studies on abnormal epigenetics regulation in AD, as well as current strategies aiming at targeting these factors in the context of AD therapy.

ZNF217: An Oncogenic Transcription Factor and Potential Therapeutic Target for Multiple Human Cancers

Zinc finger protein 217 (ZNF217) is one of the well-researched members of the Krüppel-like factor transcription factor family. ZNF217 possesses a characteristic structure of zinc finger motifs and plays a crucial role in regulating the biological activities of cells. Recent findings have revealed that ZNF217 is strongly associated with multiple aspects of cancer progression, impacting patient prognosis. Notably, ZNF217 is subject to regulation by non-coding RNAs, suggesting the potential for targeted manipulation of such RNAs as a robust therapeutic avenue for managing cancer in the future. The main purpose of this article is to provide a detailed examination of the role of ZNF217 in human malignant tumors and the regulation of its expression, and to offer new perspectives for cancer treatment.

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.

Roles of Non-Coding RNA in Alzheimer's Disease Pathophysiology

Alzheimer's disease (AD) is a chronic neurodegenerative disorder that is accompanied by deficits in memory and cognitive functions. The disease is pathologically characterised by the accumulation and aggregation of an extracellular peptide referred to as amyloid-β (Aβ) in the form of amyloid plaques and the intracellular aggregation of a hyperphosphorelated protein tau in the form of neurofibrillary tangles (NFTs) that cause neuroinflammation, synaptic dysfunction, and oxidative stress. The search for pathomechanisms leading to disease onset and progression has identified many key players that include genetic, epigenetic, behavioural, and environmental factors, which lend support to the fact that this is a multi-faceted disease where failure in various systems contributes to disease onset and progression. Although the vast majority of individuals present with the sporadic (non-genetic) form of the disease, dysfunctions in numerous protein-coding and non-coding genes have been implicated in mechanisms contributing to the disease. Recent studies have provided strong evidence for the association of non-coding RNAs (ncRNAs) with AD. In this review, we highlight the current findings on changes observed in circular RNA (circRNA), microRNA (miRNA), short interfering RNA (siRNA), piwi-interacting RNA (piRNA), and long non-coding RNA (lncRNA) in AD. Variations in these ncRNAs could potentially serve as biomarkers or therapeutic targets for the diagnosis and treatment of Alzheimer's disease. We also discuss the results of studies that have targeted these ncRNAs in cellular and animal models of AD with a view for translating these findings into therapies for Alzheimer's disease.

The Emerging Role of Autophagy-Associated lncRNAs in the Pathogenesis of Neurodegenerative Diseases

Neurodegenerative diseases (NDDs) have become a significant global public health problem and a major societal burden. The World Health Organization predicts that NDDs will overtake cancer as the second most common cause of human mortality within 20 years. Thus, it is urgently important to identify pathogenic and diagnostic molecular markers related to neurodegenerative processes. Autophagy is a powerful process for removing aggregate-prone proteins in neurons; defects in autophagy are often associated with the pathogenesis of NDDs. Long non-coding RNAs (lncRNAs) have been suggested as key regulators in neurodevelopment; aberrant regulation of lncRNAs contributes to neurological disorders. In this review, we summarize the recent progress in the study of lncRNAs and autophagy in the context of neurodegenerative disorders, especially Alzheimer's disease (AD) and Parkinson's disease (PD). The information presented here should provide guidance for future in-depth investigations of neurodegenerative processes and related diagnostic molecular markers and treatment targets.

New Insights into lncRNAs in Aβ Cascade Hypothesis of Alzheimer's Disease

Alzheimer's disease (AD) is the most common type of dementia, but its pathogenesis is not fully understood, and effective drugs to treat or reverse the progression of the disease are lacking. Long noncoding RNAs (lncRNAs) are abnormally expressed and deregulated in AD and are closely related to the occurrence and development of AD. In addition, the high tissue specificity and spatiotemporal specificity make lncRNAs particularly attractive as diagnostic biomarkers and specific therapeutic targets. Therefore, an in-depth understanding of the regulatory mechanisms of lncRNAs in AD is essential for developing new treatment strategies. In this review, we discuss the unique regulatory functions of lncRNAs in AD, ranging from Aβ production to clearance, with a focus on their interaction with critical molecules. Additionally, we highlight the advantages and challenges of using lncRNAs as biomarkers for diagnosis or therapeutic targets in AD and present future perspectives in clinical practice.

Role of Long Noncoding RNAs in the Regulation of Cellular Immune Response and Inflammatory Diseases

Long noncoding RNAs (lncRNAs) are recently discovered genetic regulatory molecules that regulate immune responses and are closely associated with the occurrence and development of various diseases, including inflammation, in humans and animals. Under specific physiological conditions, lncRNA expression varies at the cell or tissue level, and lncRNAs can bind to specific miRNAs, target mRNAs, and target proteins to participate in certain processes, such as cell differentiation and inflammatory responses, via the corresponding signaling pathways. This review article summarizes the regulatory role of lncRNAs in macrophage polarization, dendritic cell differentiation, T cell differentiation, and endothelial and epithelial inflammation. In addition, it describes the molecular mechanism of lncRNAs in acute kidney injury, hepatitis, inflammatory injury of the lung, osteoarthritis, mastitis, and neuroinflammation to provide a reference for the molecular regulatory network as well as the genetic diagnosis and treatment of inflammatory diseases in humans and animals.

Long Non-Coding RNAs, Extracellular Vesicles and Inflammation in Alzheimer's Disease

Alzheimer's Disease (AD) has currently no effective treatment; however, preventive measures have the potential to reduce AD risk. Thus, accurate and early prediction of risk is an important strategy to alleviate the AD burden. Neuroinflammation is a major factor prompting the onset of the disease. Inflammation exerts its toxic effect via multiple mechanisms. Amongst others, it is affecting gene expression via modulation of non-coding RNAs (ncRNAs), such as miRNAs. Recent evidence supports that inflammation can also affect long non-coding RNA (lncRNA) expression. While the association between miRNAs and inflammation in AD has been studied, the role of lncRNAs in neurodegenerative diseases has been less explored. In this review, we focus on lncRNAs and inflammation in the context of AD. Furthermore, since plasma-isolated extracellular vesicles (EVs) are increasingly recognized as an effective monitoring strategy for brain pathologies, we have focused on the studies reporting dysregulated lncRNAs in EVs isolated from AD patients and controls. The revised literature shows a positive association between pro-inflammatory lncRNAs and AD. However, the reports evaluating lncRNA alterations in EVs isolated from the plasma of patients and controls, although still limited, confirm the value of specific lncRNAs associated with AD as reliable biomarkers. This is an emerging field that will open new avenues to improve risk prediction and patient stratification, and may lead to the discovery of potential novel therapeutic targets for AD.

Circular RNAs: Emblematic Players of Neurogenesis and Neurodegeneration

In the fascinating landscape of non-coding RNAs (ncRNAs), circular RNAs (circRNAs) are peeping out as a new promising and appreciated class of molecules with great potential as diagnostic and prognostic biomarkers. They come from circularization of single-stranded RNA molecules covalently closed and generated through alternative mRNA splicing. Dismissed for many years, similar to aberrant splicing by-products, nowadays, their role has been regained. They are able to regulate the expression of linear mRNA transcripts at different levels acting as miRNA sponges, interacting with ribonucleoproteins or exerting a control on gene expression. On the other hand, being extremely conserved across phyla and stable, cell and tissue specific, mostly abundant than the linear RNAs, it is not surprising that they should have critical biological functions. Curiously, circRNAs are particularly expressed in brain and they build up during aging and age-related diseases. These extraordinary peculiarities make circRNAs potentially suitable as promising molecular biomarkers, especially of aging and neurodegenerative diseases. This review aims to explore new evidence on circRNAs, emphasizing their role in aging and pathogenesis of major neurodegenerative disorders, Alzheimer's disease, frontotemporal dementia, and Parkinson's diseases with a look toward their potential usefulness in biomarker searching.

Biomarkers in Human Peripheral Blood Mononuclear Cells: The State of the Art in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease, characterized by the progressive loss of lower motor neurons, weakness and muscle atrophy. ALS lacks an effective cure and diagnosis is often made by exclusion. Thus, it is imperative to search for biomarkers. Biomarkers can help in understanding ALS pathomechanisms, identification of targets for treatment and development of effective therapies. Peripheral blood mononuclear cells (PBMCs) represent a valid source for biomarkers compared to cerebrospinal fluid, as they are simple to collect, and to plasma, because of the possibility of detecting lower expressed proteins. They are a reliable model for patients’ stratification. This review provides an overview on PBMCs as a potential source of biomarkers in ALS. We focused on altered RNA metabolism (coding/non-coding RNA), including RNA processing, mRNA stabilization, transport and translation regulation. We addressed protein abnormalities (aggregation, misfolding and modifications); specifically, we highlighted that SOD1 appears to be the most characterizing protein in ALS. Finally, we emphasized the correlation between biological parameters and disease phenotypes, as regards prognosis, severity and clinical features. In conclusion, even though further studies are needed to standardize the use of PBMCs as a tool for biomarker investigation, they represent a promising approach in ALS research.

CircMIIP Contributes to Non-Small Cell Lung Cancer Progression by Binding miR-766-5p to Upregulate FAM83A Expression

BACKGROUND

Circular RNA migration and invasion inhibitory protein (circMIIP) is reported to be upregulated in non-small cell lung cancer (NSCLC) tissues compared with normal tissues. However, the role and working mechanism of circMIIP in NSCLC progression remain largely unclear.

METHODS

Cell proliferation ability was analyzed by colony formation assay, cell counting kit-8 (CCK-8) assay, and 5-ethynyl-2'-deoxyuridine assay. Cell apoptosis was assessed by flow cytometry. Transwell assays were performed to analyze the migration and invasion abilities of NSCLC cells. The interaction between microRNA-766-5p (miR-766-5p) and circMIIP or family with sequence similarity 83A (FAM83A) was validated by dual-luciferase reporter assay and RNA immunoprecipitation assay. Xenograft tumor model was established to analyze the role of circMIIP on tumor growth in vivo.

RESULTS

CircMIIP was highly expressed in NSCLC tissues and cell lines. CircMIIP knockdown restrained the proliferation, migration and invasion and induced the apoptosis of NSCLC cells. CircMIIP acted as a molecular sponge for miR-766-5p, and circMIIP silencing-mediated anti-tumor effects were largely overturned by the knockdown of miR-766-5p in NSCLC cells. miR-766-5p interacted with the 3' untranslated region (3'UTR) of FAM83A, and FAM83A overexpression largely reversed miR-766-5p accumulation-induced anti-tumor effects in NSCLC cells. CircMIIP competitively bound to miR-766-5p to elevate the expression of FAM83A in NSCLC cells. CircMIIP knockdown significantly restrained xenograft tumor growth in vivo.

CONCLUSION

CircMIIP promoted cell proliferation, migration and invasion and suppressed cell apoptosis in NSCLC cells through mediating miR-766-5p/FAM83A axis.

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

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

LncRNAs as the Regulators of Brain Function and Therapeutic Targets for Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common type of dementia and a serious threat to the health and safety of the elderly population. It has become an emerging public health problem and a major economic and social burden. However, there is currently no effective treatment for AD. Although the mechanism of AD pathogenesis has been investigated substantially, the full range of molecular factors that contribute to its development remain largely unclear. In recent years, accumulating evidence has revealed that long non-coding RNAs (lncRNAs), a type of non-coding RNA longer than 200 nucleotides, play important roles in multiple biological processes involved in AD pathogenesis. With the further exploration of genomics, the role of lncRNA in the pathogenesis of AD has been phenotypically or mechanistically studied. Herein, we systematically review the current knowledge about lncRNAs implicated in AD and elaborate on their main regulatory pathways, which may contribute to the discovery of novel therapeutic targets and drugs for AD.

Missing lnc(RNAs) in Alzheimer's Disease?

With the ongoing demographic shift towards increasingly elderly populations, it is estimated that approximately 150 million people will live with Alzheimer's disease (AD) by 2050. By then, AD will be one of the most burdensome diseases of this and potentially next centuries. Although its exact etiology remains elusive, both environmental and genetic factors play crucial roles in the mechanisms underlying AD neuropathology. Genome-wide association studies (GWAS) identified genetic variants associated with AD susceptibility in more than 40 different genomic loci. Most of these disease-associated variants reside in non-coding regions of the genome. In recent years, it has become clear that functionally active transcripts arise from these non-coding loci. One type of non-coding transcript, referred to as long non-coding RNAs (lncRNAs), gained significant attention due to their multiple roles in neurodevelopment, brain homeostasis, aging, and their dysregulation or dysfunction in neurological diseases including in AD. Here, we will summarize the current knowledge regarding genetic variations, expression profiles, as well as potential functions, diagnostic or therapeutic roles of lncRNAs in AD. We postulate that lncRNAs may represent the missing link in AD pathology and that unraveling their role may open avenues to better AD treatments.

Molecular Insight Into the Therapeutic Potential of Long Non-coding RNA-Associated Competing Endogenous RNA Axes in Alzheimer's Disease: A Systematic Scoping Review

Alzheimer’s disease (AD) is a heterogeneous degenerative brain disorder with a rising prevalence worldwide. The two hallmarks that characterize the AD pathophysiology are amyloid plaques, generated via aggregated amyloid β, and neurofibrillary tangle, generated via accumulated phosphorylated tau. At the post-transcriptional and transcriptional levels, the regulatory functions of non-coding RNAs, in particular long non-coding RNAs (lncRNAs), have been ascertained in gene expressions. It is noteworthy that a number of lncRNAs feature a prevalent role in their potential of regulating gene expression through modulation of microRNAs via a process called the mechanism of competing endogenous RNA (ceRNA). Given the multifactorial nature of ceRNA interaction networks, they might be advantageous in complex disorders (e.g., AD) investigations at the therapeutic targets level. We carried out scoping review in this research to analyze validated loops of ceRNA in AD and focus on ceRNA axes associated with lncRNA. This scoping review was performed according to a six-stage methodology structure and PRISMA guideline. A systematic search of seven databases was conducted to find eligible articles prior to July 2021. Two reviewers independently performed publications screening and data extraction, and quantitative and qualitative analyses were conducted. Fourteen articles were identified that fulfill the inclusion criteria. Studies with different designs reported nine lncRNAs that were experimentally validated to act as ceRNA in AD in human-related studies, including BACE1-AS, SNHG1, RPPH1, NEAT1, LINC00094, SOX21-AS1, LINC00507, MAGI2-AS3, and LINC01311. The BACE1-AS/BACE1 was the most frequent ceRNA pair. Among miRNAs, miR-107 played a key role by regulating three different loops. Understanding the various aspects of this regulatory mechanism can help elucidate the unknown etiology of AD and provide new molecular targets for use in therapeutic and clinical applications.

CircLPAR1/miR-212-3p/ZNF217 feedback loop promotes amyloid β-induced neuronal injury in Alzheimer's Disease

BACKGROUND

Alzheimer's Disease (AD) is a neurodegenerative disorder characterized by progressive memory loss and cognition and language impairment. CircRNA lysophosphatidic acid receptor 1 (circLPAR1) was found to be increased in AD patients, however, the potential role of circLPAR1 in AD process remains unclear.

METHODS

Beta-amyloid (Aβ) 25-35-stimulated CHP-212 and IMR-32 cells were used to perform expression and function analyses. The expression of genes and proteins was determined by qRT-PCR and Western blot. Cell proliferation and apoptosis were analyzed using cell counting kit-8 (CCK-8) assay, flow cytometry, and Western blot, respectively. ELISA analysis was used to detect the levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α). The levels of reactive oxygen species (ROS), lactate dehydrogenase (LDH) and superoxide dismutase (SOD) were detected using commercial kits. The direct interactions between miR-212-3p and ZNF217 (Zinc finger protein 217) or circLPAR1 was verified using dual-luciferase reporter and RNA immunoprecipitation (RIP) assays.

RESULTS

CircLPAR1 was highly expressed in AD patients and Aβ25-35-stimulated CHP-212 and IMR-32 cells. Knockdown of circLPAR1 suppressed Aβ25-35-induced neuronal apoptosis, inflammation, and oxidative stress. Mechanistically, circLPAR1 competitively bound to miR-212-3p to elevate its target ZNF217. Rescue experiments suggested that miR-212-3p inhibition reversed circLPAR1 silencing-evoked inhibition on neuronal injury under Aβ25-35 stimulation. Moreover, miR-212-3p re-expression reduced Aβ25-35-induced neuronal apoptosis, inflammation, and oxidative stress, which were abolished by ZNF217 up-regulation.

CONCLUSION

CircLPAR1 promotes Aβ25-35-induced apoptosis, inflammation, and oxidative stress via miR-212-3p/ZNF217 axis, suggesting a new insight into the pathogenesis of AD.

The Perspective of Dysregulated LncRNAs in Alzheimer's Disease: A Systematic Scoping Review

LncRNAs act as part of non-coding RNAs at high levels of complex and stimulatory configurations in basic molecular mechanisms. Their extensive regulatory activity in the CNS continues on a small scale, from the functions of synapses to large-scale neurodevelopment and cognitive functions, aging, and can be seen in both health and disease situations. One of the vast consequences of the pathological role of dysregulated lncRNAs in the CNS due to their role in a network of regulatory pathways can be manifested in Alzheimer's as a neurodegenerative disease. The disease is characterized by two main hallmarks: amyloid plaques due to the accumulation of β-amyloid components and neurofibrillary tangles (NFT) resulting from the accumulation of phosphorylated tau. Numerous studies in humans, animal models, and various cell lines have revealed the role of lncRNAs in the pathogenesis of Alzheimer's disease. This scoping review was performed with a six-step strategy and based on the Prisma guideline by systematically searching the publications of seven databases. Out of 1,591 records, 69 articles were utterly aligned with the specified inclusion criteria and were summarized in the relevant table. Most of the studies were devoted to BACE1-AS, NEAT1, MALAT1, and SNHG1 lncRNAs, respectively, and about one-third of the studies investigated a unique lncRNA. About 56% of the studies reported up-regulation, and 7% reported down-regulation of lncRNAs expressions. Overall, this study was conducted to investigate the association between lncRNAs and Alzheimer's disease to make a reputable source for further studies and find more molecular therapeutic goals for this disease.

LncRNA Neat1/miR-298-5p/Srpk1 Contributes to Sevoflurane-Induced Neurotoxicity

Sevoflurane is a widely used volatile anesthetic, that can cause long-term neurotoxicity and learning and memory impairment. Long non-coding RNAs (lncRNAs) have been demonstrated to function as key mediators in neurotoxicity. This study aimed to investigate the effects of lncRNA Neat1 on sevoflurane-induced neurotoxicity. The expression of Neat1, miR-298-5p, and Srpk1 was measured by RT-qPCR. Cell viability, cell apoptosis, inflammation markers, and reactive oxygen species (ROS) generation were examined by CCK-8, TUNEL, ELISA, and the ROS kit. The interaction between miR-298-5p and Neat1 or Srpk1 was confirmed by luciferase reporter assay. In our study, it was found that sevoflurane aggravated neurotoxicity through inhibiting cell viability and enhancing cell apoptosis, neuroinflammation, and ROS generation. Neat1 was up-regulated in sevoflurane-treated HT22 cells, and Neat1 knockdown improved sevoflurane-mediated neurotoxicity. Through the exploration of the ceRNA mechanism, we found that Neat1 bound with miR-298-5p, and Srpk1 was a direct target gene of miR-298-5p. Finally, rescue assays proved that up-regulation of Srpk1 reversed the effects of Neat1 knockdown on neurotoxicity. In conclusion, our study revealed that lncRNA Neat1 facilitated sevoflurane-stimulated neurotoxicity by sponging miR-298-5p to up-regulate Srpk1. These findings might provide novel insights into the treatment of sevoflurane-induced neurotoxicity.

lncRNA SNHG1 Knockdown Alleviates Amyloid-β-Induced Neuronal Injury by Regulating ZNF217 via Sponging miR-361-3p in Alzheimer's Disease

BACKGROUND

Long noncoding RNAs have been proven to play an important role in the progression of Alzheimer's disease (AD). However, the function of small nucleolar RNA host gene 1 (SNHG1) in AD progression remains to be studied.

OBJECTIVE

To explore the role of SNHG1 in AD progression and clarify its potential mechanism.

METHODS

Amyloid β-protein (Aβ) was used to construct an AD cell model in vitro. The expression levels of SNHG1 and miR-361-3p were determined by quantitative real-time polymerase chain reaction. Cell viability and apoptosis were measured by cell counting kit 8 assay and flow cytometry. The levels of apoptosis-related proteins and zinc finger gene 217 (ZNF217) protein were evaluated by western blot analysis. Additionally, the contents of inflammatory cytokines and oxidative stress markers were tested by enzyme-linked immunosorbent assay. Furthermore, dual-luciferase reporter and RNA immunoprecipitation assays were used to verify the interaction between miR-361-3p and SNHG1 or ZNF217.

RESULTS

Aβ could induce cell injury, while resveratrol could reverse this effect. SNHG1 expression was positively regulated by Aβ and negatively regulated by resveratrol. SNHG1 knockdown could reverse the promotion effect of Aβ on cell injury. Moreover, SNHG1 sponged miR-361-3p, and miR-361-3p targeted ZNF217. Additionally, miR-361-3p overexpression reversed the promotion effect of SNHG1 overexpression on cell injury, and ZNF217 silencing also reversed the promotion effect of miR-361-3p inhibitor on cell injury.

CONCLUSION

SNHG1 promoted cell injury by regulating the miR-361-3p/ZNF217 axis, which might provide a theoretical basis for molecular therapy of AD.

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

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

Long non-coding RNA ZFAS1 alleviates bupivacaine-induced neurotoxicity by regulating the miR-421/zinc finger protein564 (ZNF564) axis

This research aimed to explore the biological role of long non-coding RNA (lncRNA) ZFAS1 in bupivacaine-induced neurotoxicity. The levels of lncRNA ZFAS1, miR-421, and zinc finger protein 564 (ZNF564) were detected by RT-qPCR. MTT and TUNEL assays were utilized to evaluate cell viability and apoptosis, respectively. Caspase-3 activity was measured by the caspase-3 activity assay kit. The binding ability between miR-421 and ZFAS1 or ZNF564 was confirmed by Rip and dual-luciferase reporter assays. In this study, it was found that the levels of ZFAS1 and ZNF564 were gradually upregulated and miR-421 expression was downregulated with increasing concentrations of bupivacaine. Functional assays indicated that the silencing of ZFAS1 suppressed cell viability and facilitated cell apoptosis of SH-SY5Y cells, while overexpression of ZFAS1 had the opposite effects. Moreover, it was identified that miR-421 was a target of ZFAS1, and ZFAS1 regulated the bupivacaine-induced neurotoxicity via miR-421. In addition, we confirmed that ZNF564 was a downstream target of miR-421. The upregulation of miR-421 decreased the cell viability, and increased the cell apoptosis rate and caspase-3 activity, while the upregulation of ZND564 partially abolished these effects. Finally, it was demonstrated that ZFAS1 could upregulate the expression of ZNF564 by targeting miR-421. In conclusion, our results demonstrated that ZFAS1 alleviated bupivacaine-induced neurotoxicity through the miR-421/ZNF564 axis, suggesting a new strategy for the amelioration of bupivacaine-induced neurotoxicity.

Expression of Linear and Circular lncRNAs in Alzheimer's Disease

Alzheimer's disease is a neurodegenerative disorder of the elderly described by progressive cognitive debility. Recent studies have displayed the significance of linear and circular long non-coding RNAs (lncRNAs) in the pathobiology of Alzheimer's disease. These studies have reported the downregulation of MALAT1, while the upregulation of NEAT1, RP11-543N12.1, SOX21-AS1, BDNF-AS, BACE1-AS, ANRIL, XIST, and some other linear lncRNAs in clinical samples are obtained from these patients or animal models of Alzheimer's disease. A number of circRNAs such as ciRS-7, ciRS-7, circNF1-419, circHDAC9, circ_0000950,and circAβ-a have been shown to partake in the pathogenesis of this disorder. In the present manuscript, we provide a review of the impact of linear and circular lncRNAs in the pathobiology of Alzheimer's disease and their potential application as markers for this neurodegenerative condition.

Advances with Long Non-Coding RNAs in Alzheimer's Disease as Peripheral Biomarker

One of the most compelling needs in the study of Alzheimer’s disease (AD) is the characterization of cognitive decline peripheral biomarkers. In this context, the theme of altered RNA processing has emerged as a contributing factor to AD. In particular, the significant role of long non-coding RNAs (lncRNAs) associated to AD is opening new perspectives in AD research. This class of RNAs may offer numerous starting points for new investigations about pathogenic mechanisms and, in particular, about peripheral biomarkers. Indeed, altered lncRNA signatures are emerging as potential diagnostic biomarkers. In this review, we have collected and fully explored all the presented data about lncRNAs and AD in the peripheral system to offer an overview about this class of non-coding RNAs and their possible role in AD.

The Role of Non-coding RNAs in Alzheimer's Disease: From Regulated Mechanism to Therapeutic Targets and Diagnostic Biomarkers

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder. AD is characterized by the production and aggregation of beta-amyloid (Aβ) peptides, hyperphosphorylated tau proteins that form neurofibrillary tangles (NFTs), and subsequent neuroinflammation, synaptic dysfunction, autophagy and oxidative stress. Non-coding RNAs (ncRNAs) can be used as potential therapeutic targets and biomarkers due to their vital regulatory roles in multiple biological processes involved in disease development. The involvement of ncRNAs in the pathogenesis of AD has been increasingly recognized. Here, we review the ncRNAs implicated in AD and elaborate on their main regulatory pathways, which might have contributions for discovering novel therapeutic targets and drugs for AD.

Competing Endogenous RNA Networks as Biomarkers in Neurodegenerative Diseases

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

Effect of lncRNA WT1-AS regulating WT1 on oxidative stress injury and apoptosis of neurons in Alzheimer's disease via inhibition of the miR-375/SIX4 axis

Objective: To study the effect of lncRNA WT1-AS on oxidative stress injury (OSI) and apoptosis of neurons in Alzheimer's disease (AD) and its specific mechanisms related to the microRNA-375 (miR-375)/SIX4 axis and WT1 expression.

Results: After bioinformatic prediction, WT1-AS was found to be downregulated in Aβ_25-35treated SH-SY5Y cells, and WT1-AS overexpression inhibited WT1 expression. WT1 could target miR-375 to promote its expression. miR-375 bound to SIX4, and miR-375 overexpression inhibited SIX4 expression. WT1-AS inhibited OSI and apoptosis, while WT1 and miR-375 overexpression or SIX4 silencing reversed the WT1-AS effect on OSI and apoptosis. In vivo experiments revealed that WT1-AS improved learning/memory abilities and inhibited OSI and apoptosis in AD mice.

Conclusion: Overexpression of WT1-AS can inhibit the miR-375/SIX4 axis, OSI and neuronal apoptosis in AD by inhibiting WT1 expression.

Methods: Related lncRNAs were identified, and miR-375 downstream targets were predicted. WT1-AS, WT1, miR-375 and SIX4 expression was detected in a cell model induced by Aβ_25-35. The binding of WT1 with miR-375 and that of miR-375 with SIX4 were further confirmed. Adenosine triphosphate (ATP), reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and lactate dehydrogenase (LDH) activities, and apoptosis levels were tested after mitochondrial membrane potential observation. Learning/memory abilities and neuronal apoptosis were tested in a mouse model.

LncRNA BACE1-AS Promotes Autophagy-Mediated Neuronal Damage Through The miR-214-3p/ATG5 Signalling Axis In Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disease and is characterized by progressive memory loss and cognitive dysfunction. Long non-coding RNAs (lncRNAs) have been shown to be among the most promising biomarkers and therapeutic targets of AD. Here, we aimed to investigate whether lncRNA BACE1-AS plays a role in the potential mechanisms of AD. The expression of BACE1-AS, miR-214-3p and ATG5 mRNA was detected using qRT-PCR. The expression of the LC3, P62, ATG5, Bcl-2, p-Tau and cleaved-caspase 3 proteins was examined using western blot analysis. Cell apoptosis, cytotoxicity and ROS levels were estimated using flow cytometry, an LDH kit and a DCFH-DA assay, respectively. The interaction between BACE1-AS or ATG5 and miR-214-3p was validated using a dual-luciferase reporter assay. HE staining and a TUNEL assay were employed to evaluate hippocampal neuronal injury. The BACE1-AS level was found to be upregulated in serum samples of AD patients, brain tissues of AD transgenic (Tg) mice and Aβ_1-42-treated SH-SY5Y cells. Autophagy activity was increased in both Tg mice and Aβ_1-42-treated cells. BACE1-AS knockdown alleviated Aβ_1-42-induced cell injury. Rapamycin abolished the protective effects of sh BACE1-AS against Aβ_1-42 induced cell injury. BACE1-AS indirectly regulated ATG5 expression by binding miR-214-3p. The miR-214-3p inhibitor reversed the protective effects of sh BACE1-AS and sh ATG5 against Aβ_1-42-induced cell injury. Knockdown of BACE1-AS alleviated neuronal injury by repressing autophagy in vivo. Our findings demonstrate that silencing of BACE1-AS alleviated neuronal injury by regulating autophagy through the miR-214-3p/ATG5 signalling axis in AD.

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

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

LncRNA-MYL2-2 and miR-124-3p Are Associated with Perioperative Neurocognitive Disorders in Patients after Cardiac Surgery

BACKGROUND

Perioperative neurocognitive disorders (PND) resulting from cardiac surgery is a complication with high morbidity and mortality. However, the pathogenesis is unknown.

METHODS

For the sake of investigating the risk factors and mechanism of PND, we collected the characteristics and neurological scores of patients undergoing cardiac surgery in the Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University and Affiliated Hospital of Southwest Medical University from Jan 1, 2016 to Dec 11, 2018.

RESULTS

We found that age and left atrial thrombus are independent risk factors for PND after cardiac surgery. Furthermore, the serum of 29 patients was collected on the 7th day after cardiac surgery for detecting the expression of lncRNA-MYL2-2 and miR-124-3p. Increased lncRNA-MYL2-2 and decreased miR-124-3p in serum were associated with the decline of patients' cognition.

CONCLUSIONS

LncRNA-MYL2-2 and miRNA-124-3p may jointly participate in the occurrence and development of PND after cardiac surgery. These important findings are advantaged to further understand the pathogenesis of PND and prevent it, provide new biomarkers for the diagnosis and monitoring of PND.

MiR-9-5p inhibits mitochondrial damage and oxidative stress in AD cell models by targeting GSK-3β

This study aims to investigate the effects and underlying mechanisms of overexpression microRNA-9-5p (miR-9-5p) on the Aβ-induced mouse hippocampal neuron cell line HT22. Different concentrations of Aβ_25-35 (10, 20, 40, 80, and 160 μM) treatment were used to establish AD model in HT22 cells. The CCK-8 assay was used to measure the cell viability. The mRNA expression levels of miR-9-5p and glycogen synthase kinase-3β (GSK-3β) were determined by RT-qPCR. HT22 cell apoptosis was analyzed flow cytometry. MiR-9-5p was down-regulated in Aβ_25-35-induced HT22 cells. GSK-3β is a functional target for miR-9-5p. MiR-9-5p overexpression inhibited Aβ_25-35-induced mitochondrial dysfunction, cell apoptosis, and oxidative stress by regulating GSK-3β expression in HT22 cells. Furthermore, through targeting GSK-3β, overexpression of miR-9-5p partly activated nuclear factor Nrf2/Keap1 signaling, including part increases of Nrf2, HO-1, SOD-1, GCLC expression and slight decrease of Keap1 expression. Our results showed miR-9-5p may play a powerful role in the pathogenesis of AD.

Source of Dietary Fat in Pig Diet Affects Adipose Expression of Genes Related to Cancer, Cardiovascular, and Neurodegenerative Diseases

It has been known for many years that excessive consumption of saturated fats has proatherogenic properties, contrary to unsaturated fats. However, the molecular mechanism covering these effects is not fully understood. In this paper, we aimed to identify differentially expressed genes (DEGs) using RNA-sequencing, following feeding pigs with different sources of fat. After comparison of adipose samples from three dietary groups (rapeseed oil (n = 6), beef tallow (n = 5), coconut oil (n = 5)), we identified 29 DEGs (adjusted p-value < 0.05, fold change > 1.3) between beef tallow and rapeseed oil and 2 genes between coconut oil and rapeseed oil groups. No differentially expressed genes were observed between coconut oil and beef tallow groups. Almost all 29 DEGs between rapeseed oil and beef tallow groups are connected to neurodegenerative, cardiovascular diseases, or cancer (e.g., PLAU, CYBB, NCF2, ZNF217, CHAC1, CTCFL). Functional analysis of these genes revealed that they are associated with fluid shear stress response, complement and coagulation cascade, ROS signaling, neurogenesis, and regulation of protein binding and protein catabolic processes. Furthermore, gene set enrichment analysis (GSEA) of the whole datasets from all three comparisons suggests that both beef tallow and coconut oil may trigger changes in the expression level of genes crucial in the pathogenesis of civilization diseases.

Molecular mechanism of myofibroblast formation and strategies for clinical drugs treatments in hypertrophic scars

Hypertrophic scars (HTS) commonly occurred after burn and trauma. It was characterized by the excessive deposition of extracellular matrix with the inadequate remodeling, which could result in severe physiological and psychological problems. However, the effective available prevention and treatment measures were still limited. The main pathological feature of HTS was the excessive formation of myofibroblasts, and they persist in the repaired tissue. To better understand the mechanics of this process, this review focused on the characteristics and formation of myofibroblasts, the main effector cells in HTS. We summarized the present theories and opinions on myofibroblasts formation from the perspective of related signaling pathways and epigenetic regulation, such as DNA methylation, miRNA/lncRNA/ceRNA action, histone modification, and so forth for a better understanding on the development of HTS. This information might assist in developing effective experimental and clinical treatment strategies. Additionally, we also summarized currently known clinical strategies for HTS treatment, including traditional drugs, molecular medicine, stem cells, and exosomes.

Optimization of Degradation Conditions with PRG, a Polysaccharide from Phellinus ribis, by RSM and the Neuroprotective Activity in PC12 Cells Damaged by Aβ25-35

In the previous work, we found PRG, a polysaccharide from Phellinus ribis, exhibited neurotrophic activity. To obtain an active structural unit with lower molecular weight, PRG was degraded to prepare the degraded PRG (DPRG) using ascorbic acid and H₂O₂. The aim of the paper was to obtain DPRG by optimizing the degradation conditions using response surface methodology (RSM) and to study its protective effects of PC12 cells induced by Aβ_25–35. The optimum conditions were as follows; the concentration of H₂O₂-Vc was 17 mM and degradation temperature was 50 °C; when degradation time was 1.6 h, the experimental response value of PC12 cell viability was 83.4 ± 0.15%, which was in accordance with the predicted value (83.5%). We also studied the protective effects of DPRG against the Aβ_25–35-induced neurotoxicity and explored the underlying mechanism. The results showed that treatment with DPRG could attenuate PC12 cells death. The mechanism was relative to the inhibition of cell apoptosis by increasing the MMP level and decreasing the protein expression of cytochrome C (Cytc) in PC12 cells. In conclusion, DPRG with lower molecular weight was obtained successfully. It possessed neuroprotective properties and might be a candidate for neurodegenerative disease treatment.

Retracted Article: Berberine alleviates amyloid beta-induced injury in Alzheimer's disease by miR-107/ZNF217

Berberine plays a neuroprotective role in neurodegenerative disorders, including Alzheimer's disease (AD). However, the underlying mechanism by which berberine inhibits AD progression remains largely unclear. The AD model was established using PC12 cells after treatment of amyloid beta (Aβ)_25-35. Cells were transfected with microRNA (miRNA)-107 mimic, inhibitor, zinc finger protein 217 (ZNF217) overexpression or corresponding negative controls. Cell viability, apoptosis and inflammatory cytokine secretion were measured by MTT, flow cytometry or enzyme linked immunosorbent assay, respectively. The expressions of miR-107, ZNF217 and phosphorylated tau (p-Tau) were detected by quantitative real-time polymerase chain reaction or Western blot. The association between miR-107 and ZNF217 was explored by luciferase reporter assay and RNA immunoprecipitation. Berberine attenuated Aβ_25-35-induced viability suppression in PC12 cells. Moreover, berberine inhibited the Aβ_25-35-induced increase of inflammatory cytokine expression, apoptosis and p-Tau level in PC12 cells. miR-107 expression was reduced in Aβ_25-35-treated PC12 cells and its overexpression alleviated Aβ_25-35-induced injury, which was further weakened by combination with berberine. ZNF217 was a target of miR-107 and its addition reversed miR-107-mediated inhibition of inflammatory injury, apoptosis and phosphorylation of tau. Besides, ZNF217 protein level was decreased by berberine via regulating miR-107 in Aβ_25-35-treated PC12 cells. Berberine protected against Aβ_25-35-induced inflammatory injury, apoptosis and phosphorylation of tau by regulating miR-107 and ZNF217, indicating berberine as a promising neuroprotective agent for therapeutics of AD.

Berberine plays a neuroprotective role in neurodegenerative disorders, including Alzheimer's disease (AD).