MicroRNA-107 Ameliorates Damage in a Cell Model of Alzheimer's Disease by Mediating the FGF7/FGFR2/PI3K/Akt Pathway

Coenzyme Q10 alleviates AlCl3 and D-galactose induced Alzheimer via modulating oxidative burden and TLR-4/MAPK pathways and regulation microRNA in rat brain

Alzheimer's disease (ad) is the most progressive form of neurodegenerative disease resulting in cognitive and non-cognitive deficits. Coenzyme Q10 (CoQ10) is an anti-inflammatory and anti-oxidative stress supplement that can improve inflammation and oxidative stress associated with ad. This study aimed to explore the protective potential of coenzyme Q10 (CoQ10). It also sought to uncover any synergistic effects when combined with donepezil, an acetylcholinesterase inhibitor, in treating Alzheimer's disease in rats, focusing on the modulation of the TLR-4/MAPK pathway and regulation of microRNA. The experiment involved seventy rats categorized into different groups: control, Reference group (donepezil 10 mg/kg/P.O.), CoQ10 alone (1,200 mg/kg/P.O.), ad-model (D-galactose (120 mg/kg/i.p) + Alcl3 (50 mg/kg/P.O.)), donepezil co-treatment, CoQ10 co-treatment, and CoQ10 + donepezil co-treatment. Behavioral parameter was defined using the Morris-Maze test (MMT) and various assessments, such as GABA, oxidative stress, Aβ1-42, ion homeostasis, toll-like receptor-4 (TLR-4), mitogen-activated protein kinase-1 (MAPK-1), micro-RNA (mir-106b, mir-107, and mir-9) were measured. Immunohistological staining was used to assess structural abnormalities in hippocampus. CoQ10 treatment demonstrated memory improvement, enhanced locomotion, and increased neuronal differentiation, mainly through the activation of the TLR-4/MAPK pathway and regulation of mir-106b, mir-107, and mir-9.

Highlights

Coenzyme Q10 (CoQ10) improved the rats' passive avoidance memory impairment caused by D-gal and AlCl3. ad led to the alteration of the TLR-4/MAPK pathways.CoQ10 as a protective agent, diminishes oxidative burden, improve ion homeostasis.CoQ10 counteracts Alzheimer's disease by enhancing neurotransmitter parameter and regulating the MicroRNA.CoQ10 lowered accumulation of Aβ plaque in the hippocampal neurons of D-Gal and AlCl3-treated rats.One promising therapeutic method was the combination of donepezil and CoQ10 therapy.

Potential therapeutic targets for Alzheimer's disease: Fibroblast growth factors and their regulation of ferroptosis, pyroptosis and autophagy

Alzheimer's disease (AD) is a progressively worsening neurodegenerative disorder characterized primarily by the deposition of amyloid beta (Aβ) plaques in the brain and the abnormal aggregation of tau protein forming neurofibrillary tangles. These pathological changes lead to impaired neuronal function and cell death, subsequently affecting the structure and function of the brain. Fibroblast growth factors (FGFs) are a group of proteins that play crucial roles in various biological processes, including cell proliferation, differentiation, and survival. This article reviews the expression and regulation of FGFs in the central nervous system and how they affect neuronal survival, as well as the changes in FGF signaling pathways and its regulation of programmed cell death in AD. It particularly focuses on the impact of FGF1, FGF2, FGF21, other members of the FGF family, and FGFR on the pathophysiological mechanisms of AD. The potential of the PI3K/AKT/GSK-3β, Wnt/β-catenin, and NF-κB signaling pathways as targets for AD treatment is also discussed. Furthermore, the relationship between FGF-regulated ferroptosis, Pyroptosis and Autophagy and AD is explored, along with the role of these mechanisms in improving the progression of AD.

Intranasal Carrier-Free Nanomodulator Addresses Both Symptomatology and Etiology of Alzheimer's Disease by Restoring Neuron Plasticity and Reprogramming Lesion Microenvironment

The unsatisfactory treatment outcome of Alzheimer's disease (AD) can be attributed to two primary factors, the intricate pathogenic mechanisms leading to restricted treatment effectiveness against single targets and the hindered drug accumulation in brain due to blood-brain barrier obstruction. Therefore, we developed a carrier-free nanomodulator (NanoDS) through the self-assembly of donepezil and simvastatin for direct nose-to-brain delivery. This approach facilitated a rapid and efficient traversal through the nasal epithelial barrier, enabling subsequent drug release and achieving multiple therapeutic effects. Among them, donepezil effectively ameliorated the symptoms of AD and restored synaptic plasticity. Simvastatin exerted a neurotrophic effect and facilitated the clearance of amyloid-β aggregation. At the same time, NanoDS demonstrated effective anti-inflammatory and antioxidative stress effects. This therapy for AD is approached from both symptomatic and etiological perspectives. In the treatment of FAD4T transgenic mice, it highly improved spatial memory impairment and cognitive deficits while restoring the homeostasis of brain microenvironment. Collectively, our study presented a paradigm for both achieving efficient brain delivery and offering pleiotropic therapies for AD.

Insights into the Role of microRNAs as Clinical Tools for Diagnosis, Prognosis, and as Therapeutic Targets in Alzheimer's Disease

Neurodegenerative diseases (NDDs) are a diverse group of neurological disorders characterized by alterations in the structure and function of the central nervous system. Alzheimer's disease (AD), characterized by impaired memory and cognitive abilities, is the most prevalent type of senile dementia. Loss of synapses, intracellular aggregation of hyperphosphorylated tau protein, and extracellular amyloid-β peptide (Aβ) plaques are the hallmarks of AD. MicroRNAs (miRNAs/miRs) are single-stranded ribonucleic acid (RNA) molecules that bind to the 3' and 5' untranslated regions of target genes to cause post-transcriptional gene silencing. The brain expresses over 70% of all experimentally detected miRNAs, and these miRNAs are crucial for synaptic function and particular signals during memory formation. Increasing evidence suggests that miRNAs play a role in AD pathogenesis and we provide an overview of the role of miRNAs in synapse formation, Aβ synthesis, tau protein accumulation, and brain-derived neurotrophic factor-associated AD pathogenesis. We further summarize and discuss the role of miRNAs as potential therapeutic targets and biomarkers for AD detection and differentiation between early- and late-stage AD, based on recent research. In conclusion, altered expression of miRNAs in the brain and peripheral circulation demonstrates their potential as biomarkers and therapeutic targets in AD.

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.

Exploring the Regulatory Landscape of Dementia: Insights from Non-Coding RNAs

Dementia, a multifaceted neurological syndrome characterized by cognitive decline, poses significant challenges to daily functioning. The main causes of dementia, including Alzheimer's disease (AD), frontotemporal dementia (FTD), Lewy body dementia (LBD), and vascular dementia (VD), have different symptoms and etiologies. Genetic regulators, specifically non-coding RNAs (ncRNAs) such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are known to play important roles in dementia pathogenesis. MiRNAs, small non-coding RNAs, regulate gene expression by binding to the 3' untranslated regions of target messenger RNAs (mRNAs), while lncRNAs and circRNAs act as molecular sponges for miRNAs, thereby regulating gene expression. The emerging concept of competing endogenous RNA (ceRNA) interactions, involving lncRNAs and circRNAs as competitors for miRNA binding, has gained attention as potential biomarkers and therapeutic targets in dementia-related disorders. This review explores the regulatory roles of ncRNAs, particularly miRNAs, and the intricate dynamics of ceRNA interactions, providing insights into dementia pathogenesis and potential therapeutic avenues.

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.

miR-107-5p ameliorates neurological damage, oxidative stress, and immune responses in mice with Alzheimer's disease by suppressing the Toll-like receptor 4 (TLR4)/nuclear factor-kappaB(NF-κB) pathway

Alzheimer's disease (AD) is a progressively debilitating neurodegenerative condition primarily affecting the elderly. Emerging research suggests that microRNAs (miRNAs) play a role in the development of AD. This study investigates the impact of miR-107-5p on neurological damage, oxidative stress, and immune responses in AD. We utilized APP/PS1 mice as AD mouse models and C57BL/6 J mice as controls. AD mice received treatment with agomir miR-107-5p (to overexpress miR-107-5p) or BAY11-7082 (an NF-κB pathway inhibitor). We evaluated learning and memory abilities through the Morris water maze test. Histopathological changes, hippocampal neuron distribution, and apoptosis were assessed using hematoxylin-eosin, Nissl, and TUNEL staining. Reactive oxygen species (ROS) levels, amyloid-Aβ (Aβ1-40/42) contents, and inflammatory factors (TNF-α, IL-6, IL-1β) in hippocampal tissues were measured using ROS kits and enzyme-linked immunosorbent assay (ELISA). Microglial activation in hippocampal tissues was observed under a fluorescence microscope. miR-107-5p's binding to TLR4 was predicted via the TargetScan database and confirmed through a dual-luciferase assay. miR-107-5p expression, along with TLR4, APOE, and TREM2 in hippocampal tissue homogenate, and NF-κB p65 protein expression in the nucleus and cytoplasm were assessed via RT-qPCR and Western blot. Overexpression of miR-107-5p ameliorated hippocampal neurological damage, oxidative stress, and immune responses. This was evidenced by improved enhanced learning/memory abilities, reduced Aβ1-40 and Aβ1-42 levels, diminished neuronal injuries, decreased ROS and TNF-α, IL-6, and IL-1β levels, increased APOE and TREM2 levels, and suppressed microglial activation. miR-107-5p directly targeted and inhibited TLR4 expression, leading to reduced nuclear translocation of NF-κB p65 in the NF-κB pathway. Inhibition of the NF-κB pathway similarly improved neurological damage, oxidative stress, and immune response in AD mice. miR-107-5p exerts its beneficial effects by suppressing the TLR4/NF-κB pathway, ultimately ameliorating neurological damage, oxidative stress, and immune responses in AD mice.

Mechanism and Therapeutic Prospect of miRNAs in Neurodegenerative Diseases

MicroRNAs (miRNAs) are the smallest class of noncoding RNAs, which widely exist in animals and plants. They can inhibit translation or overexpression by combining with mRNA and participate in posttranscriptional regulation of genes, resulting in reduced expression of target proteins, affecting the development, growth, aging, metabolism, and other physiological and pathological processes of animals and plants. It is a powerful negative regulator of gene expression. It mediates the information exchange between different cellular pathways in cellular homeostasis and stress response and regulates the differentiation, plasticity, and neurotransmission of neurons. In neurodegenerative diseases, in addition to the complex interactions between genetic susceptibility and environmental factors, miRNAs can serve as a promising diagnostic tool for diseases. They can also increase or reduce neuronal damage by regulating the body's signaling pathways, immune system, stem cells, gut microbiota, etc. They can not only affect the occurrence of diseases and exacerbate disease progression but also promote neuronal repair and reduce apoptosis, to prevent and slow down the development of diseases. This article reviews the research progress of miRNAs on the mechanism and treatment of neurodegenerative diseases in the nervous system. This trial is registered with NCT01819545, NCT02129452, NCT04120493, NCT04840823, NCT02253732, NCT02045056, NCT03388242, NCT01992029, NCT04961450, NCT03088839, NCT04137926, NCT02283073, NCT04509271, NCT02859428, and NCT05243017.

MicroRNA networks linked with BRCA1/2, PTEN, and common genes for Alzheimer's disease and breast cancer share highly enriched pathways that may unravel targets for the AD/BC comorbidity treatment

MicroRNAs (miRNAs) are involved in the regulation of various cellular processes including pathological conditions. MiRNA networks have been extensively researched in age-related degenerative diseases, such as cancer, Alzheimer's disease (AD), and heart failure. Thus, miRNA has been studied from different approaches, in vivo, in vitro, and in silico including miRNA networks. Networks linking diverse biomedical entities unveil information not readily observable by other means. This work focuses on biological networks related to Breast cancer susceptibility 1 (BRCA1) in AD and breast cancer (BC). Using various bioinformatics approaches, we identified subnetworks common to AD and BC that suggest they are linked. According to our results, miR-107 was identified as a potentially good candidate for both AD and BC treatment (targeting BRCA1/2 and PTEN in both diseases), accompanied by miR-146a and miR-17. The analysis also confirmed the involvement of the miR-17-92 cluster, and miR-124-3p, and highlighted the importance of poorly researched miRNAs such as mir-6785 mir-6127, mir-6870, or miR-8485. After filtering the in silico analysis results, we found 49 miRNA molecules that modulate the expression of at least five genes common to both BC and AD. Those 49 miRNAs regulate the expression of 122 genes in AD and 93 genes in BC, from which 26 genes are common genes for AD and BC involved in neuron differentiation and genesis, cell differentiation and migration, regulation of cell cycle, and cancer development. Additionally, the highly enriched pathway was associated with diabetic complications, pointing out possible interplay among molecules underlying BC, AD, and diabetes pathology.

Revealing the Mechanisms of Byu dMar 25 in the Treatment of Alzheimer's Disease through Network Pharmacology, Molecular Docking, and In Vivo Experiment

BACKGROUND

Alzheimer's disease (AD) is the most common neurodegenerative disease, severely reducing the cognitive level and life quality of patients. Byu dMar 25 (BM25) has been proved to have a therapeutic effect on AD. However, the pharmacological mechanism is still unclear. Therefore, this study aims to reveal the potential mechanism of BM25 affecting AD from the perspective of network pharmacology and experimental validation.

METHODS

The potential active ingredients of BM25 were obtained from the TCMSP database and literature. Possible targets were predicted using SwissTargetPrediction tools. AD-related genes were identified by using GeneCards, OMIM, DisGeNET, and Drugbank databases. The candidate genes were obtained by extraction of the intersection network. Additionally, the "drug-target-disease" network was constructed by Cytoscape 3.7.2 for visualization. The PPI network was constructed by the STRING database, and the core network modules were filtered by Cytoscape 3.7.2. Enrichment analysis of GO and KEGG was carried out in the Metascape platform. Ledock software was used to dock the critical components with the core target. Furthermore, protein levels were evaluated by immunohistochemistry.

RESULTS

In this study, 112 active components, 1112 disease candidate genes, 3084 GO functions, and 277 KEGG pathways were obtained. Molecular docking showed that the effective components of BM25 in treating AD were β-asarone and hydroxysafflor yellow A. The most important targets were APP, PIK3R1, and PIK3CA. Enrichment analysis indicated that the Golgi genetic regulation, peroxidase activity regulation, phosphatidylinositol 3-kinase complex IA, 5-hydroxytryptamine receptor complexes, cancer pathways, and neuroactive ligand-receptor interactions played vital roles against AD. The rat experiment verified that BM25 affected PI3K-Akt pathway activation in AD.

CONCLUSIONS

This study reveals the mechanism of BM25 in treating AD with network pharmacology, which provides a foundation for further study on the molecular mechanism of AD treatment.

Targeting Novel microRNAs in Developing Novel Alzheimer's Disease Treatments

Alzheimer's disease (AD) is considered a multifactorial disease and a significant cause of dementia during aging. This neurodegenerative disease process is classically divided into two different pathologies cerebral accumulation of amyloid-β and hyperphosphorylated neurofibrillary tau tangles. In recent years, massive efforts have been made to treat AD by decreasing amyloid-β and tau in the brains of patients with AD, with no success. The dysfunction of a wide range of microRNAs promotes the generation and insufficient clearance of amyloid-β (Aβ) and increases tau plaques which are the pathophysiological markers of AD. Disturbance of these microRNAs is associated with mitochondrial dysfunction, oxidative damage, inflammation, apolipoprotein E4 (APOE4) pathogenic process, synaptic loss, and cognitive deficits induced by AD. Targeting a specific microRNA to restore AD-induced impairments at multiple stages might provide a promising approach for developing new drugs and therapeutic strategies for patients with AD. This review focuses on different mechanisms of microRNAs in AD pathophysiology.

MicroRNA-125a-3p Modulate Amyloid β-Protein through the MAPK Pathway in Alzheimer's Disease

BACKGROUND

MicroRNA (miR)-125a-3p is reported to play an important role in some central nervous system diseases, such as Alzheimer's disease (AD). However, a study has not been conducted on the mechanism of miR-125a-3p in the pathological process of AD.

METHODS

First, we assessed the expression of miR-125a-3p in AD cohort. Subsequently, we altered the expressions of miR-125a-3p to assess its role in cell viability, cell apoptosis, amyloid-β (Aβ) metabolism, and synaptic activity. Finally, we identified its potential mechanism underlying AD pathology.

RESULTS

This study unveiled the potential function of miR-125a-3p through modulating amyloid precursor protein processing. Additionally, miR-125a-3p influenced cell survival and activated synaptic expression through the modulation of Aβ metabolism in the mitogen-activated protein kinase (MAPK) pathway via fibroblast growth factor receptor 2.

CONCLUSION

Our study indicates that targeting miR-125a-3p may be an applicable therapy for AD in the future. However, more in vitro and in vivo studies with more samples are needed to confirm these results.

Fibroblast growth factor 7 alleviates myocardial infarction by improving oxidative stress via PI3Kα/AKT-mediated regulation of Nrf2 and HXK2

Acute myocardial infarction (MI) triggers oxidative stress, which worsen cardiac function, eventually leads to remodeling and heart failure. Unfortunately, effective therapeutic approaches are lacking. Fibroblast growth factor 7 (FGF7) is proved with respect to its proliferative effects and high expression level during embryonic heart development. However, the regulatory role of FGF7 in cardiovascular disease, especially MI, remains unclear. FGF7 expression was significantly decreased in a mouse model at 7 days after MI. Further experiments suggested that FGF7 alleviated MI-induced cell apoptosis and improved cardiac function. Mechanistic studies revealed that FGF7 attenuated MI by inhibiting oxidative stress. Overexpression of FGF7 actives nuclear factor erythroid 2-related factor 2 (Nrf2) and scavenging of reactive oxygen species (ROS), and thereby improved oxidative stress, mainly controlled by the phosphatidylinositol-3-kinase α (PI3Kα)/AKT signaling pathway. The effects of FGF7 were partly abrogated in Nrf2 deficiency mice. In addition, overexpression of FGF7 promoted hexokinase2 (HXK2) and mitochondrial membrane translocation and suppressed mitochondrial superoxide production to decrease oxidative stress. The role of HXK2 in FGF7-mediated improvement of mitochondrial superoxide production and protection against MI was verified using a HXK2 inhibitor (3-BrPA) and a HXKII VDAC binding domain (HXK2VBD) peptide, which competitively inhibits localization of HXK2 on mitochondria. Furthermore, inhibition of PI3Kα/AKT signaling abolished regulation of Nrf2 and HXK2 by FGF7 upon MI. Together, these results indicate that the cardio protection of FGF7 under MI injury is mostly attributable to its role in maintaining redox homeostasis via Nrf2 and HXK2, which is mediated by PI3Kα/AKT signaling.

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The expression of FGF7 in cardiomyocytes is decreased upon myocardial infarction (MI).

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Overexpression of FGF7 in the heart protects against cardiomyocytes apoptosis in a rodent model of MI.

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FGF7 attenuates MI-induced cardiac apoptosis via maintaining redox homeostasis.

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FGF7 maintains redox homeostasis by promoting mitochondrial HXK2 localization and Nrf2 nuclear translocation.

Circ_0049472 regulates the damage of Aβ-induced SK-N-SH and CHP-212 cells by mediating the miR-107/KIF1B axis

Alzheimer's disease (AD) is a neurodegenerative disease that seriously affects the life and health of the elderly. Studies have found that circular RNAs (circRNAs) are associated with human diseases, including AD. Hsa_circ_0049472 has been uncovered to be overexpressed in AD, but the role of circ_0049472 remains unclear. AD patients were recruited to collect cerebrospinal fluid (CSF) and serum samples. Amyloid beta (Aβ)-induced SK-N-SH and CHP-212 cells were used as the AD cell models in vitro. Quantitative real-time PCR (qRT-PCR) was used to assess the expression of circ_0049472, microRNA-107 (miR-107) and kinesin family member 1B (KIF1B). Cell counting kit-8 assay tested the cell viability, and flow cytometry measured cell apoptosis. The levels of proliferating cell nuclear antigen (PCNA), BCL2 Associated X (Bax) and kinesin family member 1B (KIF1B) protein were examined by western blot. In addition, the relative inflammatory cytokines (TNF-α, IL-6 and IL-1β) were detected by enzyme-linked immunosorbent assay (ELISA). The malondialdehyde (MDA) level and superoxide dismutase (SOD) activity were measured by relative kits. Dual-luciferase reporter assays and RNA pull-down assay verified the relationship between miR-107 and circ_0049472 or KIF1B. Circ_0049472 and KIF1B were overexpressed in AD patient-derived cerebrospinal fluid (CSF) and serum samples, as well as Aβ-induced SK-N-SH and CHP-212 cells. Silencing circ_0049472 promoted cell proliferation, and inhibited cell apoptosis in Aβ-induced SK-N-SH and CHP-212 cells. MiR-107 was a target of circ_0049472. MiR-107 silencing abolished the cell viability and apoptosis affected by down-regulation of circ_0049472 in Aβ-induced SK-N-SH and CHP-212 cells. Besides, miR-107 targeted KIF1B, and overexpressed KIF1B reverted miR-107 elevation-mediated effects on cell apoptosis, inflammation, and oxidative stress of Aβ-induced SK-N-SH and CHP-212 cells. Circ_0049472 modulated KIF1B by serving as a miR-107 decoy, thereby mediating Aβ-induced neurotoxicity, suggesting that circ_0049472 may be involved in AD pathogenesis.

New developments in the biology of fibroblast growth factors

The fibroblast growth factor (FGF) family is composed of 18 secreted signaling proteins consisting of canonical FGFs and endocrine FGFs that activate four receptor tyrosine kinases (FGFRs 1-4) and four intracellular proteins (intracellular FGFs or iFGFs) that primarily function to regulate the activity of voltage-gated sodium channels and other molecules. The canonical FGFs, endocrine FGFs, and iFGFs have been reviewed extensively by us and others. In this review, we briefly summarize past reviews and then focus on new developments in the FGF field since our last review in 2015. Some of the highlights in the past 6 years include the use of optogenetic tools, viral vectors, and inducible transgenes to experimentally modulate FGF signaling, the clinical use of small molecule FGFR inhibitors, an expanded understanding of endocrine FGF signaling, functions for FGF signaling in stem cell pluripotency and differentiation, roles for FGF signaling in tissue homeostasis and regeneration, a continuing elaboration of mechanisms of FGF signaling in development, and an expanding appreciation of roles for FGF signaling in neuropsychiatric diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology Congenital Diseases > Stem Cells and Development Cancer > Stem Cells and Development.

Circ-HUWE1 Knockdown Alleviates Amyloid-β-Induced Neuronal Injury in SK-N-SH Cells via miR-433-3p Release-Mediated FGF7 Downregulation

Alzheimer's disease (AD) is a progressive neurodegenerative disease, characterized by Amyloid-β accumulation-induced neuronal injury. Emerging evidence shows that circular RNA (circRNA) is involved in AD development. The aim of this study was to illustrate the role of circ-HUWE1 in Amyloid-β accumulation-induced neuronal injury. Quantitative real-time PCR (qPCR) or western blot was conducted for the expression analysis of circ-HUWE1, miR-433-3p, and fibroblast growth factor 7 (FGF7). In functional assays, cell viability was determined by CCK-8 assay, and cell apoptosis was examined by flow cytometry assay, the protein levels of apoptosis-related markers, and caspase1 or caspase3 activity. The release of pro-inflammatory factors was monitored by ELISA. The predicted binding relationship between miR-433-3p and circ-HUWE1 or FGF7 was validated by dual-luciferase reporter assay. We discovered that circ-HUWE1 absence alleviated Amyloid-β-induced cell viability degradation, cell apoptosis, and inflammatory responses in SK-N-SH cells. MiR-433-3p was a target of circ-HUWE1, and miR-433-3p inhibition reversed the effects of circ-HUWE1 knockdown. In addition, FGF7 was a downstream target of miR-433-3p whose function could be abolished by FGF7 reintroduction. Circ-HUWE1 positively regulated FGF7 expression via competitively targeting miR-433-3p. Moreover, circ-HUWE1 knockdown activated the WNT signaling pathway in Amyloid-β-treated SK-N-SH cells by targeting the miR-433-3p/FGF7 axis. In conclusion, circ-HUWE1 knockdown alleviates Amyloid-β-induced neuronal injury in SK-N-SH cells via miR-433-3p release-mediated FGF7 depletion.

MicroRNA Alteration, Application as Biomarkers, and Therapeutic Approaches in Neurodegenerative Diseases

MicroRNAs (miRNAs) are essential post-transcriptional gene regulators involved in various neuronal and non-neuronal cell functions and play a key role in pathological conditions. Numerous studies have demonstrated that miRNAs are dysregulated in major neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, amyotrophic lateral sclerosis, or Huntington’s disease. Hence, in the present work, we constructed a comprehensive overview of individual microRNA alterations in various models of the above neurodegenerative diseases. We also provided evidence of miRNAs as promising biomarkers for prognostic and diagnostic approaches. In addition, we summarized data from the literature about miRNA-based therapeutic applications via inhibiting or promoting miRNA expression. We finally identified the overlapping miRNA signature across the diseases, including miR-128, miR-140-5p, miR-206, miR-326, and miR-155, associated with multiple etiological cellular mechanisms. However, it remains to be established whether and to what extent miRNA-based therapies could be safely exploited in the future as effective symptomatic or disease-modifying approaches in the different human neurodegenerative disorders.

Alzheimer’s Disease: An Update and Insights Into Pathophysiology

Alzheimer’s disease (AD) is an irreversible brain disorder associated with slow, progressive loss of brain functions mostly in older people. The disease processes start years before the symptoms are manifested at which point most therapies may not be as effective. In the hippocampus, the key proteins involved in the JAK2/STAT3 signaling pathway, such as p-JAK2-Tyr1007 and p-STAT3-Tyr705 were found to be elevated in various models of AD. In addition to neurons, glial cells such as astrocytes also play a crucial role in the progression of AD. Without having a significant effect on tau and amyloid pathologies, the JAK2/STAT3 pathway in reactive astrocytes exhibits a behavioral impact in the experimental models of AD. Cholinergic atrophy in AD has been traced to a trophic failure in the NGF metabolic pathway, which is essential for the survival and maintenance of basal forebrain cholinergic neurons (BFCN). In AD, there is an alteration in the conversion of the proNGF to mature NGF (mNGF), in addition to an increase in degradation of the biologically active mNGF. Thus, the application of exogenous mNGF in experimental studies was shown to improve the recovery of atrophic BFCN. Furthermore, it is now coming to light that the FGF7/FGFR2/PI3K/Akt signaling pathway mediated by microRNA-107 is also involved in AD pathogenesis. Vascular dysfunction has long been associated with cognitive decline and increased risk of AD. Vascular risk factors are associated with higher tau and cerebral beta-amyloid (Aβ) burden, while synergistically acting with Aβ to induce cognitive decline. The apolipoprotein E4 polymorphism is not just one of the vascular risk factors, but also the most prevalent genetic risk factor of AD. More recently, the research focus on AD shifted toward metabolisms of various neurotransmitters, major and minor nutrients, thus giving rise to metabolomics, the most important “omics” tool for the diagnosis and prognosis of neurodegenerative diseases based on an individual’s metabolome. This review will therefore proffer a better understanding of novel signaling pathways associated with neural and glial mechanisms involved in AD, elaborate potential links between vascular dysfunction and AD, and recent developments in “omics”-based biomarkers in AD.

Inhibition of Long non-coding RNA zinc finger antisense 1 improves functional recovery and angiogenesis after focal cerebral ischemia via microRNA-144-5p/fibroblast growth factor 7 axis

Long non-coding RNA zinc finger antisense 1 (ZFAS1) has been probed in cerebral ischemia, while the regulatory mechanism of ZFAS1 in focal cerebral ischemia (FCI) via binding to microRNA (miR)-144-5p remains rarely explored. This study aims to decipher the function of ZFAS1 on FCI via sponging miR-144-5p to modulate fibroblast growth factor 7 (FGF7). The focal cerebral ischemia rat model was established by occlusion of the middle cerebral artery (MCAO) Lentivirus vectors altering ZFAS1, miR-144-5p or FGF7 expression were injected into rats before MCAO. Then, ZFAS1, miR-144-5p, and FGF7 levels were detected, the inflammatory factor level, oxidative stress level, angiogenesis, neurological function injury and neuronal apoptosis were assessed. The binding relations among ZFAS1, miR-144-5p and FGF7 were validated. ZFAS1 and FGF7 expression was elevated, while miR-144-5p expression was reduced in FCI rats. Decreased ZFAS1 or FGF7 or enriched miR-144-5p repressed the inflammatory response, oxidative stress, neuronal apoptosis, while it improved angiogenesis, and neurological function recovery; while up-regulated ZFAS1 exerted opposite effects. The augmented miR-144-5p or silenced FGF7 reversed the effects of enriched ZFAS1. ZFAS1 sponged miR-144-5p that targeted FGF7. Inhibition of lncRNA ZFAS1 improves functional recovery and angiogenesis after FCI via miR-144-5p/FGF7 axis. This study provides novel therapeutic targets for FCI treatment.

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.

Non-coding RNAs and their bioengineering applications for neurological diseases

Engineering of cellular biomolecules is an emerging landscape presenting creative therapeutic opportunities. Recently, several strategies such as biomimetic materials, drug-releasing scaffolds, stem cells, and dynamic culture systems have been developed to improve specific biological functions, however, have been confounded with fundamental and technical roadblocks. Rapidly emerging investigations on the bioengineering prospects of mammalian ribonucleic acid (RNA) is expected to result in significant biomedical advances. More specifically, the current trend focuses on devising non-coding (nc) RNAs as therapeutic candidates for complex neurological diseases. Given the pleiotropic and regulatory role, ncRNAs such as microRNAs and long non-coding RNAs are deemed as attractive therapeutic candidates. Currently, the list of non-coding RNAs in mammals is evolving, which presents the plethora of hidden possibilities including their scope in biomedicine. Herein, we critically review on the emerging repertoire of ncRNAs in neurological diseases such as Alzheimer’s disease, Parkinson’s disease, neuroinflammation and drug abuse disorders. Importantly, we present the advances in engineering of ncRNAs to improve their biocompatibility and therapeutic feasibility as well as provide key insights into the applications of bioengineered non-coding RNAs that are investigated for neurological diseases.

Association of peripheral blood DNA methylation level with Alzheimer's disease progression

Background

Identifying biomarkers associated with Alzheimer’s disease (AD) progression may enable patient enrichment and improve clinical trial designs. Epigenome-wide association studies have revealed correlations between DNA methylation at cytosine-phosphate-guanine (CpG) sites and AD pathology and diagnosis. Here, we report relationships between peripheral blood DNA methylation profiles measured using Infinium® MethylationEPIC BeadChip and AD progression in participants from the Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort.

Results

The rate of cognitive decline from initial DNA sampling visit to subsequent visits was estimated by the slopes of the modified Preclinical Alzheimer Cognitive Composite (mPACC; mPACC_digit and mPACC_trailsB) and Clinical Dementia Rating Scale Sum of Boxes (CDR-SB) plots using robust linear regression in cognitively normal (CN) participants and patients with mild cognitive impairment (MCI), respectively. In addition, diagnosis conversion status was assessed using a dichotomized endpoint. Two CpG sites were significantly associated with the slope of mPACC in CN participants (P < 5.79 × 10⁻⁸ [Bonferroni correction threshold]); cg00386386 was associated with the slope of mPACC_digit, and cg09422696 annotated to RP11-661A12.5 was associated with the slope of CDR-SB. No significant CpG sites associated with diagnosis conversion status were identified. Genes involved in cognition and learning were enriched. A total of 19, 13, and 5 differentially methylated regions (DMRs) associated with the slopes of mPACC_trailsB, mPACC_digit, and CDR-SB, respectively, were identified by both comb-p and DMRcate algorithms; these included DMRs annotated to HOXA4. Furthermore, 5 and 19 DMRs were associated with conversion status in CN and MCI participants, respectively. The most significant DMR was annotated to the AD-associated gene PM20D1 (chr1: 205,818,956 to 205,820,014 [13 probes], Sidak-corrected P = 7.74 × 10⁻²⁴), which was associated with both the slope of CDR-SB and the MCI conversion status.

Conclusion

Candidate CpG sites and regions in peripheral blood were identified as associated with the rate of cognitive decline in participants in the ADNI cohort. While we did not identify a single CpG site with sufficient clinical utility to be used by itself due to the observed effect size, a biosignature composed of DNA methylation changes may have utility as a prognostic biomarker for AD progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01179-2.

Systematic Search for Novel Circulating Biomarkers Associated with Extracellular Vesicles in Alzheimer's Disease: Combining Literature Screening and Database Mining Approaches

miRNAs play an important role in neurodegenerative diseases. Many miRNA-target gene interactions (MTI) have been experimentally confirmed and associated with Alzheimer’s disease (AD). miRNAs may also be contained within extracellular vesicles (EVs), mediators of cellular communication and a potential source of circulating biomarkers in body fluids. Therefore, EV-associated miRNAs (EV-miRNAs) in peripheral blood could support earlier and less invasive AD diagnostics. We aimed to prioritize EV-related miRNA with AD-related genes and to identify the most promising candidates for novel AD biomarkers. A list of unique EV-miRNAs from the literature was combined with a known set of AD risk genes and enriched for MTI. Additionally, miRNAs associated with the AD phenotype were combined with all known target genes in MTI enrichment. Expression in different sample types was analyzed to identify AD-associated miRNAs with the greatest potential as AD circulating biomarkers. Four common MTI were observed between EV-miRNAs and AD-associated miRNAs: hsa-miR-375–APH1B, hsa-miR-107–CDC42SE2, hsa-miR-375–CELF2, and hsa-miR-107–IL6. An additional 61 out of 169 unique miRNAs (36.1%) and seven out of 84 unique MTI (8.3%), observed in the body fluids of AD patients, were proposed as very strong AD-circulating biomarker candidates. Our analysis summarized several potential novel AD biomarkers, but further studies are needed to evaluate their potential in clinical practice.

In silico Analysis of Polymorphisms in microRNAs Deregulated in Alzheimer Disease

BACKGROUND

Alzheimer's disease (AD) is a degenerative condition characterized by progressive cognitive impairment and dementia. Findings have revolutionized current knowledge of miRNA in the neurological conditions. Two regulatory mechanisms determine the level of mature miRNA expression; one is miRNA precursor processing, and the other is gene expression regulation by transcription factors. This study is allocated to the in-silico investigation of miRNA's SNPs and their effect on other cell mechanisms.

METHODS

We used databases which annotate the functional effect of SNPs on mRNA-miRNA and miRNA-RBP interaction. Also, we investigated SNPs which are located on the promoter or UTR region.

RESULTS

miRNA SNP3.0 database indicated several SNPs in miR-339 and miR-34a in the upstream and downstream of pre-miRNA and mature miRNAs. While, for some miRNAs miR-124, and miR-125, no polymorphism was observed, and also miR-101 with ΔG -3.1 and mir-328 with ΔG 5.8 had the highest and lowest potencies to produce mature microRNA. SNP2TFBS web-server presented several SNPs which altered the Transcription Factor Binding Sites (TFBS) or generated novel TFBS in the promoter regions of related miRNA. At last, RBP-Var database provided a list of SNPs which alter miRNA-RBP interaction pattern and can also influence other miRNAs' expression.

DISCUSSION

The results indicated that SNPs microRNA affects both miRNA function and miRNA expression. Our study expands molecular insight into how SNPs in different parts of miRNA, including the regulatory (promoter), the precursor (pre-miRNA), functional regions (seed region of mature miRNA), and RBP-binding motifs, which theoretically may be correlated to the Alzheimer's disease.

The Eminent Role of microRNAs in the Pathogenesis of Alzheimer's Disease

Alzheimer's disease (AD) is an irrevocable neurodegenerative condition characterized by the presence of senile plaques comprising amassed β-amyloid peptides (Aβ) and neurofibrillary tangles mainly comprising extremely phosphorylated Tau proteins. Recent studies have emphasized the role of microRNAs (miRNAs) in the development of AD. A number of miRNAs, namely, miR-200a-3p, miR-195, miR-338-5p, miR-34a-5p, miR-125b-5p, miR-132, miR-384, miR-339-5p, miR-135b, miR-425-5p, and miR-339-5p, have been shown to participate in the development of AD through interacting with BACE1. Other miRNAs might affect the inflammatory responses in the course of AD. Aberrant expression of several miRNAs in the plasma samples of AD subjects has been shown to have the aptitude for differentiation of AD subjects from healthy subjects. Finally, a number of AD-modifying agents affect miRNA profile in cell cultures or animal models. We have performed a comprehensive search and summarized the obtained data about the function of miRNAs in AD in the current review article.