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

lncRNA MIR600HG Knockdown Alleviates Cognitive Impairment in Alzheimer's Disease Through NEDD4L Mediated PINK1 Degradation

BACKGROUND

Growing evidence has demonstrated that long non-coding RNAs (lncRNAs) play a critical role in Alzheimer's disease (AD), which is characterized by sustained mitochondrial dysfunction, inevitable memory loss, and cognitive decline. However, the potential function of lncRNAs MIR600 Host Gene (MIR600HG) in AD remains unanswered.

OBJECTIVE

Our study aimed to investigate the role of MIR600HG and its related molecular mechanism in AD.

METHODS

The expression of MIR600HG was examined by qRT-PCR. The MIR600HG interacting proteins were identified by RNA pull-down assay and mass spectrometry and verified by RNA immunoprecipitation. Immunofluorescence staining was applied to examine the colocalization of PINK1 and NEDD4L. The PINK1 level and the activation of autophagy were detected by immunoblotting. Morris water maze test was performed to evaluate cognitive decline in AD mice model.

RESULTS

MIR600HG expression was elevated during aging in two different types of AD transgenic mouse models. Next, we found that increased MIR600HG directly interact with NEDD4L, which promoted PINK1 ubiquitination and degradation, and as well as autophagy activation. Additionally, MIR600HG promoted Aβ production and suppressed Cytochrome C Oxidase activity. Administration of AAV-shMIR600HG restored the Cytochrome C Oxidase activity and inhibited Aβ production. Furthermore, PINK1 overexpression or MIR600HG knockdown significantly ameliorated the cognitive impairment in APP/PS1 mice. PINK1 depletion recovered the spatial memory defect in the AAV-shMIR600HG injected APP/PS1 mice.

CONCLUSION

MIR600HG was increased in AD and promoted AD pathogenesis. Targeting MIR600HG significantly improved cognitive function in AD mice, which could pave the way for exciting new avenues in AD therapeutic strategy research.

Small Molecule Drugs Targeting Non-Coding RNAs as Treatments for Alzheimer's Disease and Related Dementias

Despite the enormous burden of Alzheimer's disease and related dementias (ADRD) on patients, caregivers, and society, only a few treatments with limited efficacy are currently available. While drug development conventionally focuses on disease-associated proteins, RNA has recently been shown to be druggable for therapeutic purposes as well. Approximately 70% of the human genome is transcribed into non-protein-coding RNAs (ncRNAs) such as microRNAs, long ncRNAs, and circular RNAs, which can adopt diverse structures and cellular functions. Many ncRNAs are specifically enriched in the central nervous system, and their dysregulation is implicated in ADRD pathogenesis, making them attractive therapeutic targets. In this review, we first detail why targeting ncRNAs with small molecules is a promising therapeutic strategy for ADRD. We then outline the process from discovery to validation of small molecules targeting ncRNAs in preclinical studies, with special emphasis on primary high-throughput screens for identifying lead compounds. Screening strategies for specific ncRNAs will also be included as examples. Key challenges-including selecting appropriate ncRNA targets, lack of specificity of small molecules, and general low success rate of neurological drugs and how they may be overcome-will be discussed throughout the review.

Identification and Validation of the lncRNA BACE1-AS as Immune-Related Influencing Factor in Tumorigenesis following Pan-Carcinoma Analysis

BACKGROUND

The lncRNA BACE1-AS was identified as a plasma molecular marker in the early diagnosis of Alzheimer's disease, but its role in tumors remains poorly defined.

METHODS

The expression patterns, genomic mutation, and prognostic significance of BACE1-AS in pan-cancers were compared by analyzing 32 types of tumors from The Cancer Genome Atlas and cBioPortal databases. The relationships between BACE1-AS expression levels and the degree of immune cell infiltration, immune components, and immune-related genes were explored. The possible molecular mechanisms of BACE1-AS in tumors were explored using gene set enrichment analysis (GSEA). Finally, the role of BACE1-AS in hepatocellular carcinoma was confirmed via quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

BACE1-AS expression levels were significantly upregulated in LIHC, GBM, KIRC, CHOL, STAD, KICH, COAD, and PRAD. Higher expression levels of BACE1-AS were associated with worse overall survival in patients with HNSC and LIHC, while the opposite was found in PCPG and THCA. The overall mutation rate of BACE1-AS in pan-cancer was only approximately 0.9%, and it occurred mainly in uveal melanoma and uterine carcinoma. Generally, BACE1-AS expression was negatively correlated with the immune microenvironment. BACE1-AS expression was mainly related to naïve B cells, activated memory CD4 T cells, monocytes, M1 macrophages, M2 macrophages, and resting mast cells. The potential mechanisms of BACE1-AS in tumors were mainly via regulating the activities of B cell-mediated immunity, immune response regulating cell surface receptor signaling, RNA binding in posttranscriptional gene silencing, B cell receptor signaling pathways, and immune receptor activity. Finally, the qRT-PCR results confirmed that the expression levels of BACE1-AS in hepatocellular carcinoma cell lines were upregulated.

CONCLUSIONS

Overall, our results suggest that BACE1-AS is associated with the expression, prognosis, and rate of immune cell infiltration of most tumors. Thus, BACE1-AS may be a potential target for immunotherapies aimed at improving cancer patient outcomes.

Non-coding RNAs: New players in mitophagy and neurodegeneration

Mitophagy controls mitochondrial quality to maintain cellular homeostasis, while aberrations in this process are responsible for neurodegenerative diseases. Mitophagy is initiated through the recruitment of autophagosomes in a ubiquitin-dependent or ubiquitin-independent manner under different stress conditions. Although the detailed molecular mechanisms of how mitophagy processes influence neurodegeneration remain largely uncharacterized, there is mounting evidence indicating that non-coding RNAs (ncRNAs), a variety of endogenous regulators, including microRNAs and long non-coding RNAs, extensively participate in mitophagy processes and play pivotal roles in the aging process and neurodegenerative diseases. Here, we reviewed the major mitophagy pathways modulated by some classical and newly found ncRNAs and summarized the diverse mechanisms in a regulatory network. We also discussed the generalizability of ncRNAs in the development of common neurodegenerative diseases related to proteotoxicity and the importance of mitophagy in the pathogenesis of these diseases. In summary, we propose that ncRNAs act as linkers between mitophagy and neurodegeneration, showing the potential therapeutic application of mitophagy regulation mediated by ncRNAs in neurodegenerative diseases.

Autophagy and apoptosis cascade: which is more prominent in neuronal death?

Autophagy and apoptosis are two crucial self-destructive processes that maintain cellular homeostasis, which are characterized by their morphology and regulated through signal transduction mechanisms. These pathways determine the fate of cellular organelle and protein involved in human health and disease such as neurodegeneration, cancer, and cardiovascular disease. Cell death pathways share common molecular mechanisms, such as mitochondrial dysfunction, oxidative stress, calcium ion concentration, reactive oxygen species, and endoplasmic reticulum stress. Some key signaling molecules such as p53 and VEGF mediated angiogenic pathway exhibit cellular and molecular responses resulting in the triggering of apoptotic and autophagic pathways. Herein, based on previous studies, we describe the intricate relation between cell death pathways through their common genes and the role of various stress-causing agents. Further, extensive research on autophagy and apoptotic machinery excavates the implementation of selective biomarkers, for instance, mTOR, Bcl-2, BH3 family members, caspases, AMPK, PI3K/Akt/GSK3β, and p38/JNK/MAPK, in the pathogenesis and progression of neurodegenerative diseases. This molecular phenomenon will lead to the discovery of possible therapeutic biomolecules as a pharmacological intervention that are involved in the modulation of apoptosis and autophagy pathways. Moreover, we describe the potential role of micro-RNAs, long non-coding RNAs, and biomolecules as therapeutic agents that regulate cell death machinery to treat neurodegenerative diseases. Mounting evidence demonstrated that under stress conditions, such as calcium efflux, endoplasmic reticulum stress, the ubiquitin-proteasome system, and oxidative stress intermediate molecules, namely p53 and VEGF, activate and cause cell death. Further, activation of p53 and VEGF cause alteration in gene expression and dysregulated signaling pathways through the involvement of signaling molecules, namely mTOR, Bcl-2, BH3, AMPK, MAPK, JNK, and PI3K/Akt, and caspases. Alteration in gene expression and signaling cascades cause neurotoxicity and misfolded protein aggregates, which are characteristics features of neurodegenerative diseases. Excessive neurotoxicity and misfolded protein aggregates lead to neuronal cell death by activating death pathways like autophagy and apoptosis. However, autophagy has a dual role in the apoptosis pathways, i.e., activation and inhibition of the apoptosis signaling. Further, micro-RNAs and LncRNAs act as pharmacological regulators of autophagy and apoptosis cascade, whereas, natural compounds and chemical compounds act as pharmacological inhibitors that rescue neuronal cell death through inhibition of apoptosis and autophagic cell death.

Gene regulation by antisense transcription: A focus on neurological and cancer diseases

Advances in high-throughput sequencing over the past decades have led to the identification of thousands of non-coding RNAs (ncRNAs), which play a major role in regulating gene expression. One emerging class of ncRNAs is the natural antisense transcripts (NATs), the RNA molecules transcribed from the opposite strand of a protein-coding gene locus. NATs are known to concordantly and discordantly regulate gene expression in both cis and trans manners at the transcriptional, post-transcriptional, translational, and epigenetic levels. Aberrant expression of NATs can therefore cause dysregulation in many biological pathways and has been observed in many genetic diseases. This review outlines the involvements and mechanisms of NATs in the pathogenesis of various diseases, with a special emphasis on neurodegenerative diseases and cancer. We also summarize recent findings on NAT knockdown and/or overexpression experiments and discuss the potential of NATs as promising targets for future gene therapies.

The neurobiology of non-coding RNAs and Alzheimer's disease pathogenesis: Pathways, mechanisms and translational opportunities

In the past two decades, advances in sequencing technology and analysis of the human and mouse genome have led to the discovery of many non-protein-coding RNAs (ncRNAs) including: microRNA, small-interfering RNAs, piwi-associated small RNAs, transfer RNA-derived small RNAs, long-non-coding RNAs and circular RNAs. Compared with healthy controls, levels of some ncRNAs are significantly altered in the central nervous system and blood of patients affected by neurodegenerative disorders like Alzheimer's disease (AD). Although the mechanisms are still not fully elucidated, studies have revealed that these highly conserved ncRNAs are important modulators of gene expression, amyloid-β production, tau phosphorylation, inflammation, synaptic plasticity and neuronal survival, all features considered central to AD pathogenesis. Despite considerable difficulties due to their large heterogeneity, and the complexity of their regulatory pathways, research in this rapidly growing field suggests that ncRNAs hold great potential as biomarkers and therapeutic targets against AD. Herein, we summarize the current knowledge regarding the neurobiology of ncRNA in the context of AD pathophysiology.

MicroRNA-214-5p involves in the protection effect of Dexmedetomidine against neurological injury in Alzheimer's disease via targeting the suppressor of zest 12

OBJECTIVE

Alzheimer's disease (AD) is a neurological disease. Dexmedetomidine (Dex) has been evidenced to exert neuroprotective effects on multiple neurological diseases, while the function of microRNA(miR)- 214-5p on Dex-mediated AD progression via targeting the suppressor of zest 12 (SUZ12) remains unclear. This study obligates to investigate the regulatory functions of Dex, miR-214-5p and SUZ12 on AD.

METHODS

The expression of miR-214-5p and SUZ12 in APPswe/PS1dE9 mice (hereinafter referred to as AD mice) was examined. Thereafter, the AD mice were treated with Dex or increased miR-214-5p or reduced SUZ12 to determine the spatial memory ability, apoptosis of hippocampal neurons and the contents of serum inflammatory and oxidative stress factors of AD mice. Finally, the target relationship between miR-214-5p and SUZ12 was detected.

RESULTS

MiR-214-5p was reduced and SUZ12 was elevated in AD mice. Dex administration reduced the apoptosis of hippocampal neurons, the contents of serum inflammatory factor and oxidative stress, and attenuated the cognitive impairment of AD mice accompanied by up-regulated miR-214-5p and down-regulated SUZ12, and the overexpression of miR-214-5p or reduction of SUZ12 could effectively enhance the Dex-treated effects on AD mice. MiR-214-5p targeted SUZ12.

CONCLUSION

Dex may have a potential neuroprotective effect on AD via the miR-214-5p/SUZ12 axis. This study provides novel therapeutic targets for AD treatment.

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.

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.

The regulatory roles of microRNAs toward pathogenesis and treatments in Huntington's disease

Huntington's disease (HD) is one of neurodegenerative diseases, and is defined as a monogenetic disease due to the mutation of Huntingtin gene. This disease affects several cellular functions in neurons, and further influences motor and cognitive ability, leading to the suffering of devastating symptoms in HD patients. MicroRNA (miRNA) is a non-coding RNA, and is responsible for gene regulation at post-transcriptional levels in cells. Since one miRNA targets to several downstream genes, it may regulate different pathways simultaneously. As a result, it raises a potential therapy for different diseases using miRNAs, especially for inherited diseases. In this review, we will not only introduce the update information of HD and miRNA, but also discuss the development of potential miRNA-based therapy in HD. With the understanding toward the progression of miRNA studies in HD, we anticipate it may provide an insight to treat this devastating disease, even applying to other genetic diseases.

Mechanism of Autonomic Exercise Improving Cognitive Function of Alzheimer's Disease by Regulating lncRNA SNHG14

This paper studied the influence of exercise on the cognitive ability of AD patients and elucidated potential mechanisms. The expression of SNHG14 was validated by qRT-PCR. The cognitive impairment of mice was examined by MWM Test. ELISA tests were applied to discover the influence of SNHG14 on inflammation. Overexpression of SNHG14 was found in AD patients and underexpression of SNHG14 was identified in these AD patients after exercise. In APP/PS1 double transgenic mice, SNHG14 reversed the protective impacts of exercise on escape latency and distance moved. The upregulation of SNHG14 also inhibited the effects of exercise on the percentage of time spent in the target quadrant and times of platform crossing. Besides, overexpression of SNHG14 reversed the repressed expression of IL-6, IL-1β, and TNF-α. In total, exercise could ameliorate cognitive disorder and inflammation activity by reducing the levels of SNHG14.