MiR-124-3p attenuates hyperphosphorylation of Tau protein-induced apoptosis via caveolin-1-PI3K/Akt/GSK3β pathway in N2a/APP695swe cells

MicroRNA-based recent research developments in Alzheimer's disease

Alzheimer's disease (AD) is a chronic neurodegenerative disorder that is characterized by memory and physical impairment in aged individuals. microRNAs (miRNAs) are small, single-stranded noncoding RNAs that induce translational repression by binding to the 3' UTR of a target mRNA. miRNAs play a crucial role in neurological activity by mediating cellular proliferation, synaptic plasticity, apoptosis and more. Ongoing research in patents and clinical trials have called attention to promising miRNAs as biomarkers and therapeutics in AD. Recent research has shown that miRNAs are aberrantly expressed in AD brain, blood, cerebrospinal fluid and serum. Attenuated miRNA expressions have diagnostic potential in AD by interacting with amyloid-β synthesis, phosphorylated tau, and neurofibrillary tangles. In this study, miRNA-29a, miRNA-125b, miRNA-34a, miRNA-146a, and miRNA-155 have shown promise as potential biomarker candidates for AD. Improving cognitive symptoms can be traced to restoring the endogenous miRNA activity by synthesizing miRNA mimics and miRNA antisense oligonucleotides. miRNA-483-5p, miRNA-188-5p, miRNA-219, miRNA135a/5p, miRNA-23/23b-3p, miRNA-124, and miRNA-455-3p are growing therapeutics for AD. However, miRNA-based therapeutics struggle outside of preclinical testing. miRNA-107, miRNA-206, miRNA-30/7, and miRNA-142-3p face bottlenecks in clinical trials due to a lack of experimental design, transparency and volunteer size. Patenting recent miRNA-based developments demonstrates the commitment in identifying a new biomarker and/or therapeutic for AD.

Extracellular vesicle-packed microRNAs profiling in Alzheimer's disease: The molecular intermediary between pathology and diagnosis

MicroRNAs (miRNAs), referring to a type of non-coding RNAs functioning in various biological processes, participate in the pathophysiology of Alzheimer's disease (AD) through increasing amyloid-beta (Aβ) production, enhancing Tau phosphorylation, and inducing neuroinflammation. Meanwhile, extracellular vesicles (EVs) have been suggested as promising carriers of AD biomarkers as they possess the ability to transmit information from cerebral tissue to peripheral blood. Inspired by the above findings, we in this review systematically generalized the roles of miRNAs in AD and explored the potential of EV-packed miRNA as biomarkers for early diagnosis of AD. Through the detailed investigation, this review may highlight the promise of EV-packed miRNAs in advancing our understanding of AD, and underscore the imperative needs of further studies on their diagnostic potential.

Parkinson's Disease and MicroRNAs: A Duel Between Inhibition and Stimulation of Apoptosis in Neuronal Cells

Parkinson's disease (PD) is one of the most prevalent diseases of central nervous system that is caused by degeneration of the substantia nigra's dopamine-producing neurons through apoptosis. Apoptosis is regulated by initiators' and executioners' caspases both in intrinsic and extrinsic pathways, further resulting in neuronal damage. In that context, targeting apoptosis appears as a promising therapeutic approach for treating neurodegenerative diseases. Non-coding RNAs-more especially, microRNAs, or miRNAs-are a promising target for the therapy of neurodegenerative diseases because they are essential for a number of cellular processes, including signaling, apoptosis, cell proliferation, and gene regulation. It is estimated that a substantial portion of coding genes (more than 60%) are regulated by miRNAs. These small regulatory molecules can have wide-reaching consequences on cellular processes like apoptosis, both in terms of intrinsic and extrinsic pathways. Furthermore, it was recommended that a disruption in miRNA expression levels could also result in perturbation of typical apoptosis pathways, which may be a factor in certain diseases like PD. The latest research on miRNAs and their impact on neural cell injury in PD models by regulating the apoptosis pathway is summarized in this review article. Furthermore, the importance of lncRNA/circRNA-miRNA-mRNA network for regulating apoptosis pathways in PD models and treatment is explored. These results can be utilized for developing new strategies in PD treatment.

A Comprehensive Review of Membrane Transporters and MicroRNA Regulation in Alzheimer's Disease

Alzheimer's disease (AD) is a distressing neurodegenerative condition characterized by the accumulation of amyloid-beta (Aβ) plaques and tau tangles within the brain. The interconnectedness between membrane transporters (SLCs) and microRNAs (miRNAs) in AD pathogenesis has gained increasing attention. This review explores the localization, substrates, and functions of SLC transporters in the brain, emphasizing the roles of transporters for glutamate, glucose, nucleosides, and other essential compounds. The examination delves into the significance of SLCs in AD, their potential for drug development, and the intricate realm of miRNAs, encompassing their transcription, processing, functions, and regulation. MiRNAs have emerged as significant players in AD, including those associated with mitochondria and synapses. Furthermore, this review discusses the intriguing nexus of miRNAs targeting SLC transporters and their potential as therapeutic targets in AD. Finally, the review underscores the interaction between SLC transporters and miRNA regulation within the context of Alzheimer's disease, underscoring the need for further research in this area. This comprehensive review aims to shed light on the complex mechanisms underlying the causation of AD and provides insights into potential therapeutic approaches.

Role of miRNAs in neurovascular injury and repair

MicroRNAs (miRNA) are endogenously produced small, non-coded, single-stranded RNAs. Due to their involvement in various cellular processes and cross-communication with extracellular components, miRNAs are often coined the "grand managers" of the cell. miRNAs are frequently involved in upregulation as well as downregulation of specific gene expression and thus, are often found to play a vital role in the pathogenesis of multiple diseases. Central nervous system (CNS) diseases prove fatal due to the intricate nature of both their development and the methods used for treatment. A considerable amount of ongoing research aims to delineate the complex relationships between miRNAs and different diseases, including each of the neurological disorders discussed in the present review. Ongoing research suggests that specific miRNAs can play either a pathologic or restorative and/or protective role in various CNS diseases. Understanding how these miRNAs are involved in various regulatory processes of CNS such as neuroinflammation, neurovasculature, immune response, blood-brain barrier (BBB) integrity and angiogenesis is of empirical importance for developing effective therapies. Here in this review, we summarized the current state of knowledge of miRNAs and their roles in CNS diseases along with a focus on their association with neuroinflammation, innate immunity, neurovascular function and BBB.

MicroRNAs: pioneering regulators in Alzheimer's disease pathogenesis, diagnosis, and therapy

This article delves into Alzheimer's disease (AD), a prevalent neurodegenerative condition primarily affecting the elderly. It is characterized by progressive memory and cognitive impairments, severely disrupting daily life. Recent research highlights the potential involvement of microRNAs in the pathogenesis of AD. MicroRNAs (MiRNAs), short non-coding RNAs comprising 20-24 nucleotides, significantly influence gene regulation by hindering translation or promoting degradation of target genes. This review explores the role of specific miRNAs in AD progression, focusing on their impact on β-amyloid (Aβ) peptide accumulation, intracellular aggregation of hyperphosphorylated tau proteins, mitochondrial dysfunction, neuroinflammation, oxidative stress, and the expression of the APOE4 gene. Our insights contribute to understanding AD's pathology, offering new avenues for identifying diagnostic markers and developing novel therapeutic targets.

Cognitive Dysfunction and Exercise: From Epigenetic to Genetic Molecular Mechanisms

Maintaining good health is crucial, and exercise plays a vital role in achieving this goal. It offers a range of positive benefits for cognitive function, regardless of age. However, as our population ages and life expectancy increases, cognitive impairment has become a prevalent issue, often coexisting with age-related neurodegenerative conditions. This can result in devastating consequences such as memory loss, difficulty speaking, and confusion, greatly hindering one's ability to lead an ordinary life. In addition, the decrease in mental capacity has a significant effect on an individual's physical and emotional well-being, greatly reducing their overall level of contentment and causing a significant financial burden for communities. While most current approaches aim to slow the decline of cognition, exercise offers a non-pharmacological, safe, and accessible solution. Its effects on cognition are intricate and involve changes in the brain's neural plasticity, mitochondrial stability, and energy metabolism. Moreover, exercise triggers the release of cytokines, playing a significant role in the body-brain connection and its impact on cognition. Additionally, exercise can influence gene expression through epigenetic mechanisms, leading to lasting improvements in brain function and behavior. Herein, we summarized various genetic and epigenetic mechanisms that can be modulated by exercise in cognitive dysfunction.

Rosuvastatin attenuates total-tau serum levels and increases expression of miR-124-3p in dyslipidemic Alzheimer's patients: a historic cohort study

microRNAs are candidate diagnostic biomarkers for Alzheimer's disease. This study aimed to compare Silymarin with Rosuvastatin and placebo on total-Tau protein level and expression levels of microRNAs and TGF-β and COX-2 in Alzheimer's patients with secondary dyslipidemia. 36 mild AD patients with dyslipidemia were divided into three groups of 12. The first group received silymarin (140mg), the second group received placebo (140mg), and the third group recieved Rosuvastatin (10mg). Tablets were administered three times a day for Six months. The blood samples of the patients were collected before and after the intervention and the serum was separated. Using the RT-qPCR method, the expression levels of miR-124-3p and miR-125b-5p were assessed, and the serum levels of total-Tau, TGF-β, and COX-2 enzyme were measured using the ELISA method. Data were analyzed with SPSS software. In this study, the level of Δtotal-Tau was significantly lower in the Rosuvastatin group compared to the placebo (P = 0.038). Also, a significant reduction in the level of ΔTGF-β was observed in the Silymarin to Rosuvastatin group (p = 0.046) and ΔmiR-124-3p was significantly increased in the Rosuvastatin compared to the placebo group (p = 0.044). Rosuvastatin outperformed silymarin in decreasing Δtotal-Tau serum levels and enhancing expression of ΔmiR-124-3p, attributed to Rosuvastatin's capacity to lower cholesterol levels and inflammation concurrently. Conversely, silymarin was more effective than Rosuvastatin in reducing levels of ΔTGF-β. Serum miR-124-3p could serve as a promising diagnostic biomarker and a new therapeutic focus 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.

MicroRNA biomarkers as next-generation diagnostic tools for neurodegenerative diseases: a comprehensive review

Neurodegenerative diseases (NDs) are characterized by abnormalities within neurons of the brain or spinal cord that gradually lose function, eventually leading to cell death. Upon examination of affected tissue, pathological changes reveal a loss of synapses, misfolded proteins, and activation of immune cells-all indicative of disease progression-before severe clinical symptoms become apparent. Early detection of NDs is crucial for potentially administering targeted medications that may delay disease advancement. Given their complex pathophysiological features and diverse clinical symptoms, there is a pressing need for sensitive and effective diagnostic methods for NDs. Biomarkers such as microRNAs (miRNAs) have been identified as potential tools for detecting these diseases. We explore the pivotal role of miRNAs in the context of NDs, focusing on Alzheimer's disease, Parkinson's disease, Multiple sclerosis, Huntington's disease, and Amyotrophic Lateral Sclerosis. The review delves into the intricate relationship between aging and NDs, highlighting structural and functional alterations in the aging brain and their implications for disease development. It elucidates how miRNAs and RNA-binding proteins are implicated in the pathogenesis of NDs and underscores the importance of investigating their expression and function in aging. Significantly, miRNAs exert substantial influence on post-translational modifications (PTMs), impacting not just the nervous system but a wide array of tissues and cell types as well. Specific miRNAs have been found to target proteins involved in ubiquitination or de-ubiquitination processes, which play a significant role in regulating protein function and stability. We discuss the link between miRNA, PTM, and NDs. Additionally, the review discusses the significance of miRNAs as biomarkers for early disease detection, offering insights into diagnostic strategies.

Unveiling the Role of Novel miRNA PC-5P-12969 in Alleviating Alzheimer's Disease

Background

The intricate and complex molecular mechanisms that underlie the progression of Alzheimer's disease (AD) have prompted a concerted and vigorous research endeavor aimed at uncovering potential avenues for therapeutic intervention.

Objective

This study aims to elucidate the role of miRNA PC-5P-12969 in the pathogenesis of AD.

Methods

We assessed the differential expression of miRNA PC-5P-12969 in postmortem AD brains, AD animal and cell models using real-time reverse-transcriptase RT-PCR, we also checked the gene and protein expression of GSK3α and APP.

Results

Our investigation revealed a notable upregulation of miRNA PC-5P-12969 in postmortem brains of AD patients, in transgenic mouse models of AD, and in mutant APP overexpressing-HT22 cells. Additionally, our findings indicate that overexpression of miRNA PC-5P-12969 exerts a protective effect on cell survival, while concurrently mitigating apoptotic cell death. Further-more, we established a robust and specific interaction between miRNA PC-5P-12969 and GSK3α. Our luciferase reporter assays provided confirmation of the binding between miRNA PC-5P-12969 and the 3'-UTR of the GSK3α gene. Manipulation of miRNA PC-5P-12969 levels in cellular models of AD yielded noteworthy alterations in the gene and protein expression levels of both GSK3α and APP. Remarkably, the manipulation of miRNA PC-5P-12969 levels yielded significant enhancements in mitochondrial respiration and ATP production, concurrently with a reduction in mitochondrial fragmentation, thus unveiling a potential regulatory role of miRNA PC-5P-12969 in these vital cellular processes.

Conclusions

In summary, this study sheds light on the crucial role of miRNA PC-5P-12969 and its direct interaction with GSK3α in the context of AD.

Unraveling the role of miRNAs in the diagnosis, progression, and therapeutic intervention of Alzheimer's disease

Alzheimer's disease (AD) is a multifaceted, advancing neurodegenerative illness that is responsible for most cases of neurological impairment and dementia in the aged population. As the disease progresses, affected individuals may experience cognitive decline, linguistic problems, affective instability, and behavioral changes. The intricate nature of AD reflects the altered molecular mechanisms participating in the affected human brain. MicroRNAs (miRNAs, miR) are essential for the intricate control of gene expression in neurobiology. miRNAs exert their influence by modulating the transcriptome of brain cells, which typically exhibit substantial genetic activity, encompassing gene transcription and mRNA production. Presently, comprehensive studies are being conducted on AD to identify miRNA-based signatures that are indicative of the disease pathophysiology. These findings can contribute to the advancement of our understanding of the mechanisms underlying this disorder and can inform the development of therapeutic interventions based on miRNA and related RNA molecules. Therefore, this comprehensive review provides a detailed holistic analysis of the latest advances discussing the emerging role of miRNAs in the progression of AD and their possible application as potential biomarkers and targets for therapeutic interventions in future studies.

Noncoding RNAs in Alzheimer's Disease: Overview of Functional and Therapeutic Significance

Alzheimer's disease (AD) is a multifactorial disorder resulting from the complex interaction between genetic, epigenetic, and environmental factors. It represents an impending epidemic and lacks effective pharmacological interventions. The emergence of high throughput sequencing techniques and comprehensive genome evaluation has uncovered a diverse spectrum of noncoding RNA (ncRNA) families. ncRNAs are the critical modulators of an eclectic array of biological processes and are now transpiring as imperative players in diagnosing and treating various diseases, including neurodegenerative disorders. Several ncRNAs are explicitly augmented in the brain, wherein they potentially regulate cognitive abilities and other functions of the central nervous system. Growing evidence suggests the substantial role of ncRNAs as modulators of tau phosphorylation, Aβ production, neuroinflammation, and neuronal survival. It indicates their therapeutic relevance as a biomarker and druggable targets against AD. The current review summarizes the existing literature on the functional significance of ncRNAs in AD pathogenesis and its imminent implications in clinics.

Epigenetics of Alzheimer’s Disease: Past, Present and Future

Alzheimer’s disease (AD) exemplifies a looming epidemic lacking effective treatment and manifests with the accumulation of neurofibrillary tangles, amyloid-β plaques, neuroinflammation, behavioral changes, and acute cognitive impairments. It is a complex, multifactorial disorder that arises from the intricate interaction between environment and genetic factors, restrained via epigenetic machinery. Though the research progress has improved the understanding of clinical manifestations and disease advancement, the causal mechanism of detrimental consequences remains undefined. Despite the substantial improvement in recent diagnostic modalities, it is challenging to distinguish AD from other forms of dementia. Accurate diagnosis is a major glitch in AD as it banks on the symptoms and clinical criteria. Several studies are underway in exploring novel and reliable biomarkers for AD. In this direction, epigenetic alterations have transpired as key modulators in AD pathogenesis with the impeding inferences for the management of this neurological disorder. The present chapter aims to discuss the significance of epigenetic modifications reported in the pathophysiology of AD such as DNA methylation, hydroxy-methylation, methylation of mtDNA, histone modifications, and noncoding RNAs. Additionally, the chapter also describes the possible therapeutic avenues that target epigenetic modifications in AD.

Roles of microRNA-124 in traumatic brain injury: a comprehensive review

Traumatic brain injury (TBI) is a prominent global cause of mortality due to the limited availability of effective prevention and treatment strategies for this disorder. An effective molecular biomarker may contribute to determining the prognosis and promoting the therapeutic efficiency of TBI. MicroRNA-124 (miR-124) is most abundantly expressed in the brain and exerts different biological effects in a variety of diseases by regulating pathological processes of apoptosis and proliferation. Recently, increasing evidence has demonstrated the association between miR-124 and TBI, but there is still a lack of relevant literature to summarize the current evidence on this topic. Based on this review, we found that miR-124 was involved as a regulatory factor in cell apoptosis and proliferation, and was also strongly related with the pathophysiological development of TBI. MiR-124 played an essential role in TBI by interacting with multiple biomolecules and signaling pathways, such as JNK, VAMP-3, Rela/ApoE, PDE4B/mTOR, MDK/TLR4/NF-κB, DAPK1/NR2B, JAK/STAT3, PI3K/AKT, Ras/MEK/Erk. The potential benefits of upregulating miR-124 in facilitating TBI recovery have been identified. The advancement of miRNA nanocarrier system technology presents an opportunity for miR-124 to emerge as a novel therapeutic target for TBI. However, the specific mechanisms underlying the role of miR-124 in TBI necessitate further investigation. Additionally, comprehensive large-scale studies are required to evaluate the clinical significance of miR-124 as a therapeutic target for TBI.

Extracellular vesicles of human glial cells exert neuroprotective effects via brain miRNA modulation in a rat model of traumatic brain injury

Stem cell-based therapeutic approaches for neurological disorders are widely studied. Paracrine factors secreted by stem cells in vitro and delivered intranasally might allow bypassing the disadvantages associated with a surgical cell delivery procedure with likely immune rejection of a transplant. In this study, we investigated the therapeutic effect of the extracellular vesicles secreted by glial progenitor cells (GPC-EV) derived from human induced pluripotent stem cell in a traumatic brain injury model. Intranasal administration of GPC-EV to Wistar rats for 6 days improved sensorimotor functions assessed over a 14-day observation period. Beside, deep sequencing of microRNA transcriptome of GPC-EV was estimate, and was revealed 203 microRNA species that might be implicated in prevention of various brain pathologies. Modulation of microRNA pools might contribute to the observed decrease in the number of astrocytes that inhibit neurorecovery processes while enhancing neuroplasticity by decreasing phosphorylated Tau forms, preventing inflammation and apoptosis associated with secondary damage to brain tissue. The course of GPC-EV administration was promoted the increasing protein levels of NF-κB in studied areas of the rat brain, indicating NF-κB dependent mechanisms as a plausible route of neuroprotection within the damaged area. This investigation showed that GPC-EV may be representing a therapeutic approach in traumatic brain injury, though its translation into the clinic would require an additional research and development.

Caveolin-1 and lipids: Association and their dualism in oncogenic regulation

Caveolin-1 (Cav-1) is a structural protein of caveolae that functions as a molecular organizer for different cellular functions including endocytosis and cellular signaling. Cancer cells take advantage of the physical position of Cav-1, as it can communicate with extracellular matrix, help to organize growth factor receptors, redistribute cholesterol and glycosphingolipids, and finally transduce signals within the cells for oncogenesis. Recent studies emphasize the exceeding involvement of Cav-1 with different lipid bodies and in altering the metabolism, especially lipid metabolism. However, the association of Cav-1 with different lipid bodies like lipid rafts, lipid droplets, cholesterols, sphingolipids, and fatty acids is remarkably dynamic. The lipid-Cav-1 alliance plays a dual role in carcinogenesis. Both cancer progression and regression are modified and affected by the type of lipid molecule's association with Cav-1. Accordingly, this Cav-1-lipid cooperation exemplifies a cancer-type-specific treatment strategy for a better prognosis of the disease. In this review, we first present Cav-1 as an oncogenic molecule and its communication via lipid raft. We discussed the involvement of Cav-1 with lipid droplets, Cholesterol, sphingolipids, gangliosides, and ceramides. Further, we describe the Cav-1-mediated altered Fatty acid metabolism in cancer and the strategic therapeutic approaches toward Cav-1 targeting.

The microRNAs (miRs) overexpressing mesenchymal stem cells (MSCs) therapy in neurological disorders; hope or hype

Altered expression of multiple miRNAs was found to be extensively involved in the pathogenesis of different neurological disorders including Alzheimer's disease, Parkinson's disease, stroke, epilepsy, multiple sclerosis, amyotrophic lateral sclerosis, and Huntington's disease. One of the biggest concerns within gene-based therapy is the delivery of the therapeutic microRNAs to the intended place, which is obligated to surpass the biological barriers without undergoing degradation in the bloodstream or renal excretion. Hence, the delivery of modified and unmodified miRNA molecules using excellent vehicles is required. In this light, mesenchymal stem cells (MSCs) have attracted increasing attention. The MSCs can be genetically modified to express or overexpress a particular microRNA aimed with promote neurogenesis and neuroprotection. The current review has focused on the therapeutic capabilities of microRNAs-overexpressing MSCs to ameliorate functional deficits in neurological conditions.

Cognitive-exercise dual-task intervention ameliorates cognitive decline in natural aging rats via inhibiting the promotion of LncRNA NEAT1/miR-124-3p on caveolin-1-PI3K/Akt/GSK3β Pathway

Aging-related cognitive impairment (ARCI) is rapidly becoming a healthcare priority. However, there is currently no excellent cure for it. Cognitive-exercise dual-task intervention (CEDI) is a promising method to improve ARCI, while the underlying mechanisms remain unclear. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are involved in the onset, development, and rehabilitation of ARCI. This study aimed to investigate the effects of CEDI and the role of regulation of the lncRNA NEAT1/miR-124-3p on the caveolin-1-PI3K/Akt/GSK3β pathway in CEDI improving cognitive function. Forty 18-month-old natural aging rats were randomly assigned to four groups: exercise training group, cognitive training group, CEDI group, and aging control group, and underwent 12 weeks of intervention. A novel object recognition test was performed to determine the cognitive function, and the hippocampus was separated three days after the behavioral tests for further molecular detection. In an in vitro study, the mouse hippocampal neuronal cell line HT22 was cultured. MiR-124-3p and lncRNA NEAT1 were over-expressed or down-expressed, respectively. The expressions of related proteins, lncRNA, and miRNA were examined by WB and/or qRT-PCR. The results showed that compared with the aging control group, the CEDI group had a higher discrimination index, and significantly decreased the expressions of lncRNA NEAT1, and the protein expressions of caveolin-1 and p-GSK3β, while significantly increased the expressions of miR-124-3p, and the protein expressions of p-PI3K and p-Akt. Inhibition of the lncRNA NEAT1 could significantly increase the protein expressions of p-PI3K and p-Akt in HT22 cells. Upregulation of miR-124-3p decreased the protein expressions of caveolin-1 and p-GSK3β, and increased the protein expressions of p-PI3K and p-Akt significantly. Inhibition of miR-124-3p had the opposite effects. Our study demonstrated that CEDI improved cognitive function in aging rats better than a single intervention. The mechanisms of cognitive improvement could be related to the regulation of the lncRNA NEAT1/miR-124-3p on the caveolin-1-PI3K/Akt/GSK3β pathway.

Hydrogen-rich saline alleviates cardiomyocyte apoptosis by reducing expression of calpain1 via miR-124-3p

AIMS

Molecular hydrogen has been exhibited a protective function in heart diseases. Our previous study demonstrated that hydrogen-rich saline (HRS) could scavenge free radicals selectively and alleviate the inflammatory response in the myocardial ischaemia/reperfusion (I/R) injury, but the underlying mechanism has not been fully clarified.

METHODS AND RESULTS

Adult (10 weeks) C57BL/6 male mice and neonatal rat cardiomyocytes were used to establish I/R and hypoxia/reoxygenation (H/R) injury models. I/R and H/R models were treated with HRS to classify the mechanisms of cardioproctective function. In this study, we found that miR-124-3p was significantly decreased in both I/R and H/R models, while it was partially ameliorated by HRS pretreatment. HRS treatment also alleviated ischaemia-induced apoptotic cell death and increased cell viability during I/R process, whereas silencing expression of miR-124-3p abolished this protective effect. In addition, we identified calpain1 as a direct target of miR-124-3p, and up-regulation of miR-124-3 produced both activity and expression of calpain1. It was also found that compared with the HRS group, overexpression of calpain1 increased caspase-3 activities, promoted cleaved-caspase3 and Bax protein expressions, and correspondingly decreased Bcl-2, further reducing cell viability. These results illustrated that calpain1 overexpression attenuated protective effect of HRS on cardiomyocytes in H/R model.

CONCLUSIONS

The present study showed a protective effect of HRS on I/R injury, which may be associated with miR-124-3p-calpain1 signalling pathway.

The role of microRNAs in neurobiology and pathophysiology of the hippocampus

MicroRNAs (miRNAs) are short non-coding and well-conserved RNAs that are linked to many aspects of development and disorders. MicroRNAs control the expression of genes related to different biological processes and play a prominent role in the harmonious expression of many genes. During neural development of the central nervous system, miRNAs are regulated in time and space. In the mature brain, the dynamic expression of miRNAs continues, highlighting their functional importance in neurons. The hippocampus, as one of the crucial brain structures, is a key component of major functional connections in brain. Gene expression abnormalities in the hippocampus lead to disturbance in neurogenesis, neural maturation and synaptic formation. These disturbances are at the root of several neurological disorders and behavioral deficits, including Alzheimer's disease, epilepsy and schizophrenia. There is strong evidence that abnormalities in miRNAs are contributed in neurodegenerative mechanisms in the hippocampus through imbalanced activity of ion channels, neuronal excitability, synaptic plasticity and neuronal apoptosis. Some miRNAs affect oxidative stress, inflammation, neural differentiation, migration and neurogenesis in the hippocampus. Furthermore, major signaling cascades in neurodegeneration, such as NF-Kβ signaling, PI3/Akt signaling and Notch pathway, are closely modulated by miRNAs. These observations, suggest that microRNAs are significant regulators in the complicated network of gene regulation in the hippocampus. In the current review, we focus on the miRNA functional role in the progression of normal development and neurogenesis of the hippocampus. We also consider how miRNAs in the hippocampus are crucial for gene expression mechanisms in pathophysiological pathways.

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

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

Cerebrospinal fluid microRNAs as potential biomarkers in Alzheimer's disease

Alzheimer's disease (AD) is the leading form of dementia worldwide, but its early detection and diagnosis remain a challenge. MicroRNAs (miRNAs) are a group of small endogenous RNA molecules that regulate mRNA expression. Recent evidence suggests miRNAs play an important role in the five major hallmarks of AD pathophysiology: amyloidogenesis, tauopathy, neuroinflammation, synaptic dysfunction, and neuronal death. Compared to traditional biomarkers of AD, miRNAs display a greater degree of stability in cerebrospinal fluid. Moreover, aberrant changes in miRNA expression can be measured over time to monitor and guide patient treatment. Specific miRNA profiles and combinations may also be used to distinguish AD subjects from normal controls and other causes of dementia. Because of these properties, miRNAs are now being considered as promising and potential biomarkers of AD. This review comprehensively summarizes the diagnostic potential and regulatory roles miRNAs play in AD.

Common molecular signatures between coronavirus infection and Alzheimer's disease reveal targets for drug development

Cognitive decline has been reported as a common consequence of COVID-19, and studies have suggested a link between COVID-19 infection and Alzheimer's disease (AD). However, the molecular mechanisms underlying this association remain unclear. To shed light on this link, we conducted an integrated genomic analysis using a novel Robust Rank Aggregation method to identify common transcriptional signatures of the frontal cortex, a critical area for cognitive function, between individuals with AD and COVID-19. We then performed various analyses, including the KEGG pathway, GO ontology, protein-protein interaction, hub gene, gene-miRNA, and gene-transcription factor interaction analyses to identify molecular components of biological pathways that are associated with AD in the brain also show similar changes in severe COVID-19. Our findings revealed the molecular mechanisms underpinning the association between COVID-19 infection and AD development and identified several genes, miRNAs, and TFs that may be targeted for therapeutic purposes. However, further research is needed to investigate the diagnostic and therapeutic applications of these findings.

Circulating microRNAs as diagnostic biomarkers for ischemic stroke: evidence from comprehensive analysis and real-world validation

Ischemic stroke (IS) is the majority of strokes which remain the second leading cause of deaths in the last two decades. Circulating microRNAs (miRNAs) have been suggested as potential diagnostic and therapeutic tools for IS by previous studies analyzing their differential expression. However, inconclusive and controversial conclusions of these results have to be addressed. In this study, comprehensive analysis and real-world validation were performed to assess the associations between circulating miRNAs and IS. 29 studies with 112 miRNAs were extracted after manual selection and filtering, 12 differentially expressed miRNAs were obtained from our results of meta-analysis. These miRNAs were evaluated in 20 IS patients, compared to 20 healthy subjects. 4 miRNAs (hsa-let-7e-5p, hsa-miR-124-3p, hsa-miR-17-5p, hsa-miR-185-5p) exhibited the significant expression level in IS patient plasma samples. Pathway and biological process enrichment analysis for the target genes of the 4 validated miRNAs identified cellular senescence and neuroinflammation as key post-IS response pathways. The results of our analyses closely correlated with the pathogenesis and implicated pathways observed in IS subjects suggested by the literature, which may provide aid in the development of circulating diagnostic or therapeutic targets for IS patients.

Friend or foe: role of pathological tau in neuronal death

Neuronal death is one of the most common pathological hallmarks of diverse neurological diseases, which manifest varying degrees of cognitive or motor dysfunction. Neuronal death can be classified into multiple forms with complicated and unique regulatory signaling pathways. Tau is a key microtubule-associated protein that is predominantly expressed in neurons to stabilize microtubules under physiological conditions. In contrast, pathological tau always detaches from microtubules and is implicated in a series of neurological disorders that are characterized by irreversible neuronal death, such as necrosis, apoptosis, necroptosis, pyroptosis, ferroptosis, autophagy-dependent neuronal death and phagocytosis by microglia. However, recent studies have also revealed that pathological tau can facilitate neuron escape from acute apoptosis, delay necroptosis through its action on granulovacuolar degeneration bodies (GVBs), and facilitate iron export from neurons to block ferroptosis. In this review, we briefly describe the current understanding of how pathological tau exerts dual effects on neuronal death by acting as a double-edged sword in different neurological diseases. We propose that elucidating the mechanism by which pathological tau affects neuronal death is critical for exploring novel and precise therapeutic strategies for neurological disorders.

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.

Common Molecular Signatures Between Coronavirus Infection and Alzheimer's Disease Reveal Targets for Drug Development

BACKGROUND

Cognitive decline is a common consequence of COVID-19, and studies suggest a link between COVID-19 and Alzheimer's disease (AD). However, the molecular mechanisms underlying this association remain unclear.

OBJECTIVE

To understand the potential molecular mechanisms underlying the association between COVID-19 and AD development, and identify the potential genetic targets for pharmaceutical approaches to reduce the risk or delay the development of COVID-19-related neurological pathologies.

METHODS

We analyzed transcriptome datasets of 638 brain samples using a novel Robust Rank Aggregation method, followed by functional enrichment, protein-protein, hub genes, gene-miRNA, and gene-transcription factor (TF) interaction analyses to identify molecular markers altered in AD and COVID-19 infected brains.

RESULTS

Our analyses of frontal cortex from COVID-19 and AD patients identified commonly altered genes, miRNAs and TFs. Functional enrichment and hub gene analysis of these molecular changes revealed commonly altered pathways, including downregulation of the cyclic adenosine monophosphate (cAMP) signaling and taurine and hypotaurine metabolism, alongside upregulation of neuroinflammatory pathways. Furthermore, gene-miRNA and gene-TF network analyses provided potential up- and downstream regulators of identified pathways.

CONCLUSION

We found that downregulation of cAMP signaling pathway, taurine metabolisms, and upregulation of neuroinflammatory related pathways are commonly altered in AD and COVID-19 pathogenesis, and may make COVID-19 patients more susceptible to cognitive decline and AD. We also identified genetic targets, regulating these pathways that can be targeted pharmaceutically to reduce the risk or delay the development of COVID-19-related neurological pathologies and AD.

The landscape of the long non-coding RNAs and circular RNAs of the abdominal fat tissues in the chicken lines divergently selected for fatness

BACKGROUND

Excessive deposition of abdominal fat poses serious problems in broilers owing to rapid growth. Recently, the evolution of the existing knowledge on long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) have established their indispensable roles in multiple physiological metabolic processes, including adipogenesis and fat deposition. However, not much has been explored on their profiles in the abdominal fat tissues of broilers to date. In the study, we aimed to characterize the vital candidates of lncRNAs and circRNAs and their underlying regulations for abdominal fat deposition in broilers.

RESULTS

The present study sequenced the lncRNAs and circRNAs expression profiles in the abdominal fat tissues isolated from 7-week-old broilers, who were divergently selected for their fatness. It identified a total of 3359 lncRNAs and 176 circRNAs, demonstrating differential expressed (DE) 30 lncRNAs and 17 circRNAs between the fat- and lean-line broilers (|log2FC| ≥ 1, P < 0.05). Subsequently, the 20 cis-targets and 48 trans-targets of the candidate DE lncRNAs were identified for depositing abdominal fat by adjacent gene analysis and co-expression analysis, respectively. In addition, the functional enrichment analysis showed the DE lncRNAs targets and DE circRNAs host genes to be mainly involved in the cellular processes, amino/fatty acid metabolism, and immune inflammation-related pathways and GO terms. Finally, the vital 16 DE lncRNAs located in cytoplasm and specifically expressed in fat/lean line and their targets were used to construct the lncRNA-miRNA-mRNA competing endogenous RNA (ceRNA) regulatory network, comprising 7 DE lncRNAs, 28 miRNAs, 11 DE mRNAs. Notably, three lncRNAs including XR_001468036.2, XR_003077610.1 and XR_001466431.2 with the most connected degrees might play hub regulatory roles in abdominal fat deposition of broilers.

CONCLUSIONS

This study characterized the whole expression difference of lncRNAs and circRNAs between the two lines broilers with divergently ability of abdominal fat. The vital candidate DE lncRNAs/circRNAs and ceRNA regulations were identified related to the deposition of abdominal fat in chicken. These results might further improve our understanding of regulating the non-coding RNAs in obesity.

The role of microRNAs in neurodegenerative diseases: a review

MicroRNAs (miRNAs) are non-coding RNAs which are essential post-transcriptional gene regulators in various neuronal degenerative diseases and playact a key role in these physiological progresses. Neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, multiple sclerosis, and, stroke, are seriously threats to the life and health of all human health and life kind. Recently, various studies have reported that some various miRNAs can regulate the development of neurodegenerative diseases as well as act as biomarkers to predict these neuronal diseases conditions. Endogenic miRNAs such as miR-9, the miR-29 family, miR-15, and the miR-34 family are generally dysregulated in animal and cell models. They are involved in regulating the physiological and biochemical processes in the nervous system by targeting regulating different molecular targets and influencing a variety of pathways. Additionally, exogenous miRNAs derived from homologous plants and defined as botanmin, such as miR2911 and miR168, can be taken up and transferred by other species to be and then act analogously to endogenic miRNAs to regulate the physiological and biochemical processes. This review summarizes the mechanism and principle of miRNAs in the treatment of some neurodegenerative diseases, as well as discusses several types of miRNAs which were the most commonly reported in diseases. These miRNAs could serve as a study provided some potential biomarkers in neurodegenerative diseases might be an ideal and/or therapeutic targets for neurodegenerative diseases. Finally, the role accounted of the prospective exogenous miRNAs involved in mammalian diseases is described.

Synaptosome microRNAs regulate synapse functions in Alzheimer's disease

MicroRNAs (miRNAs) are found in nerve terminals, synaptic vesicles, and synaptosomes, but it is unclear whether synaptic and cytosolic miRNA populations differ in Alzheimer's disease (AD) or if synaptosomal miRNAs affect AD synapse activity. To address these questions, we generated synaptosomes and cytosolic fractions from postmortem brains of AD and unaffected control (UC) samples and analyzed them using a global Affymetrix miRNAs microarray platform. A group of miRNAs significantly differed (P < 0.0001) with high fold changes variance (+/- >200-fold) in their expressions in different comparisons: (1) UC synaptosome vs UC cytosol, (2) AD synaptosomes vs AD cytosol, (3) AD cytosol vs UC cytosol, and (4) AD synaptosomes vs UC synaptosomes. MiRNAs data analysis revealed that some potential miRNAs were consistently different across sample groups. These differentially expressed miRNAs were further validated using AD postmortem brains, brains of APP transgenic (Tg2576), Tau transgenic (P301L), and wild-type mice. The miR-501-3p, miR-502-3p, and miR-877-5p were identified as potential synaptosomal miRNAs upregulated with disease progression based on AD Braak stages. Gene Ontology Enrichment and Ingenuity Pathway Analysis of synaptosomal miRNAs showed the involvement of miRNAs in nervous system development, cell junction organization, synapse assembly formation, and function of GABAergic synapse. This is the first description of synaptic versus cytosolic miRNAs in AD and their significance in synapse function.

Advances on Therapeutic Strategies for Alzheimer's Disease: From Medicinal Plant to Nanotechnology

Alzheimer's disease (AD) is a chronic dysfunction of neurons in the brain leading to dementia. It is characterized by gradual mental failure, abnormal cognitive functioning, personality changes, diminished verbal fluency, and speech impairment. It is caused by neuronal injury in the cerebral cortex and hippocampal area of the brain. The number of individuals with AD is growing at a quick rate. The pathology behind AD is the progress of intraneuronal fibrillary tangles, accumulation of amyloid plaque, loss of cholinergic neurons, and decrease in choline acetyltransferase. Unfortunately, AD cannot be cured, but its progression can be delayed. Various FDA-approved inhibitors of cholinesterase enzyme such as rivastigmine, galantamine, donepezil, and NDMA receptor inhibitors (memantine), are available to manage the symptoms of AD. An exhaustive literature survey was carried out using SciFinder's reports from Alzheimer's Association, PubMed, and Clinical Trials.org. The literature was explored thoroughly to obtain information on the various available strategies to prevent AD. In the context of the present scenario, several strategies are being tried including the clinical trials for the treatment of AD. We have discussed pathophysiology, various targets, FDA-approved drugs, and various drugs in clinical trials against AD. The goal of this study is to shed light on current developments and treatment options, utilizing phytopharmaceuticals, nanomedicines, nutraceuticals, and gene therapy.

miR-23b-3p rescues cognition in Alzheimer's disease by reducing tau phosphorylation and apoptosis via GSK-3β signaling pathways

Dysregulated microRNA (miRNA) expression in the brain can contribute to cognitive dysfunction and aberrant tau hyperphosphorylation in Alzheimer’s disease (AD). Several studies have reported a role for microRNA-23b-3p (miR-23b-3p) in various neurologic disorders; however, its involvement in cognition-related functions remains unclear. In the present study, we investigated the potential therapeutic effects and mechanisms of miR-23b-3p in AD. miRNA profiles in the cortex of amyloid precursor protein (APP)/presenilin 1 (PS1) double transgenic mice (APP/PS1 mice) demonstrated that miR-23b-3p was reduced. This decrease was verified in APPswe cells, SAMP8 mouse brains, and plasma from AD patients. Furthermore, glycogen synthase kinase-3β (GSK-3β), a major tau kinase implicated in tau pathology, was identified as a target of miR-23b-3p. Functional in vivo studies demonstrated that intracerebroventricular delivery of miR-23b-3p in APP/PS1 mice ameliorated cognitive deficits, histopathological changes, and tau phosphorylation immunoreactivity at several sites by inhibiting GSK-3β expression and activation. Similarly, the upregulation of miR-23b-3p in APPswe cells inhibited GSK-3β-mediated tau hyperphosphorylation, Aβ_1-42 generation, and neuronal apoptosis, resulting in the suppression of the GSK-3β/p-tau and Bax/caspase-3 pathways. Collectively, our findings strongly support the hypothesis that miR-23b-3p plays a neuroprotective role in AD, thereby identifying miR-23b-3p as a promising therapeutic target for AD.

A novel approach to type 3 diabetes mechanism: The interplay between noncoding RNAs and insulin signaling pathway in Alzheimer's disease

Today, growing evidence indicates that patients with type 2 diabetes (T2D) are at a higher risk of developing Alzheimer's disease (AD). Indeed, AD as one of the main causes of dementia in people aged more than 65 years can be aggravated by insulin resistance (IR) and other metabolic risk factors related to T2D which are also linked to the function of the brain. Remarkably, a new term called "type 3 diabetes" has been suggested for those people who are diagnosed with AD while also showing the symptoms of IR and T2D. In this regard, the role of genetic and epigenetic changes associated with AD has been confirmed by many studies. On the other hand, it should be noted that the insulin signaling pathway is highly regulated by various mechanisms, including epigenetic factors. Among these, the role of noncoding RNAs (ncRNAs), including microRNAs and long noncoding RNAs has been comprehensively studied with respect to the pathology of AD and the most well-known underlying mechanisms. Nevertheless, the number of studies exploring the association between ncRNAs and the downstream targets of the insulin signaling pathway in the development of AD has notably increased in recent years. With this in view, the present study aimed to review the interplay between different ncRNAs and the insulin signaling pathway targets in the pathogenesis of AD to find a new approach in the field of combining biomarkers or therapeutic targets for this disease.

MicroRNA modulation is a potential molecular mechanism for neuroprotective effects of intranasal insulin administration in amyloid βeta oligomer induced Alzheimer's like rat model

Substantial evidence indicates that imbalance in the expression of miR-132-3p, miR-181b-5p, miR-125b-5p, miR-26a-5p, miR-124-3p, miR-146a-5p, miR-29a-3p, and miR-30a-5p in the AD brain are associated with amyloid-beta (Aβ) aggregation, tau pathology, neuroinflammation, and synaptic dysfunction, the major pathological hallmarks of Alzheimer's disease)AD(. Several studies have reported that intranasal insulin administration ameliorates memory in AD patients and animal models. However, the underlying molecular mechanisms are not yet completely elucidated. Therefore, the aim of this study was to determine whether insulin is involved in regulating the expression of AD-related microRNAs. Pursuing this objective, we first investigated the therapeutic effect of intranasal insulin on Aβ oligomer (AβO)-induced memory impairment in male rats using the Morris water maze task. Then, molecular and histological changes in response to AβO and/or insulin time course were assessed in the extracted hippocampi on days 1, 14, and 21 of the study using congo red staining, western blot and quantitative real-time PCR analyses. We observed memory impairment, Aβ aggregation, tau hyper-phosphorylation, neuroinflammation, insulin signaling dys-regulation, and down-regulation of miR-26a, miR-124, miR-29a, miR-181b, miR-125b, miR-132, and miR-146a in the hippocampus of AβO-exposed rats 21 days after AβO injection. Intranasal insulin treatment ameliorated memory impairment and concomitantly increased miR-132, miR-181b, and miR-125b expression, attenuated tau phosphorylation levels, Aβ aggregation, and neuroinflammation, and regulated the insulin signaling as well. In conclusion, our study suggest that the neuroprotective effects of insulin on memory observed in AD-like rats could be partially due to the restoration of miR-132, miR-181b, and miR-125b expression in the brain.

Molecular Biomarkers and Their Implications for the Early Diagnosis of Selected Neurodegenerative Diseases

The degeneration and dysfunction of neurons are key features of neurodegenerative diseases (NDs). Currently, one of the main challenges facing researchers and clinicians is the ability to obtain reliable diagnostic tools that will allow for the diagnosis of NDs as early as possible and the detection of neuronal dysfunction, preferably in the presymptomatic stage. Additionally, better tools for assessing disease progression in this group of disorders are also being sought. The ideal biomarker must have high sensitivity and specificity, be easy to measure, give reproducible results, and reflect the disease progression. Molecular biomarkers include miRNAs and extracellular microvesicles known as exosomes. They may be measured in two extracellular fluids of the highest importance in NDs, i.e., cerebrospinal fluid (CSF) and blood. The aim of the current review is to summarize the pathophysiology of the four most frequent NDs—i.e., Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS)—as well as current progress in the research into miRNAs as biomarkers in these major neurodegenerative diseases. In addition, we discuss the possibility of using miRNA-based therapies in the treatment of neurodegenerative diseases, and present the limitations of this type of therapy.

MicroRNAs in Alzheimer's disease: Potential diagnostic markers and therapeutic targets

Alzheimer's disease (AD) is the most common neurodegenerative disease, with cognitive decline as the primary clinical feature. According to epidemiological statistics, 50 million people worldwide are currently affected by Alzheimer's disease. Although new drugs such as aducanumab have been approved for use in the treatment of AD, none of them have reversed the progression of AD. MicroRNAs (miRNAs) are small molecule RNAs that exert their biological functions by regulating the expression of intracellular proteins, and differential abundance and varieties are found between the central and peripheral tissues of AD patients and healthy controls. This article will summarise the changes of miRNAs in the AD process, and the potential role of diagnostic markers and therapeutic targets in AD will be explored.

Sporadic Alzheimer's Disease- and Neurotoxicity-Related microRNAs Affecting Key Events of Tau-Driven Adverse Outcome Pathway Toward Memory Loss

BACKGROUND

A complex network of aging-related homeostatic pathways that are sensitive to further deterioration in the presence of genetic, systemic, and environmental risk factors, and lifestyle, is implicated in the pathogenesis of progressive neurodegenerative diseases, such as sporadic (late-onset) Alzheimer's disease (sAD).

OBJECTIVE

Since sAD pathology and neurotoxicity share microRNAs (miRs) regulating common as well as overlapping pathological processes, environmental neurotoxic compounds are hypothesized to exert a risk for sAD initiation and progression.

METHODS

Literature search for miRs associated with human sAD and environmental neurotoxic compounds was conducted. Functional miR analysis using PathDip was performed to create miR-target interaction networks.

RESULTS

The identified miRs were successfully linked to the hypothetical starting point and key events of the earlier proposed tau-driven adverse outcome pathway toward memory loss. Functional miR analysis confirmed most of the findings retrieved from literature and revealed some interesting findings. The analysis identified 40 miRs involved in both sAD and neurotoxicity that dysregulated processes governing the plausible adverse outcome pathway for memory loss.

CONCLUSION

Creating miR-target interaction networks related to pathological processes involved in sAD initiation and progression, and environmental chemical-induced neurotoxicity, respectively, provided overlapping miR-target interaction networks. This overlap offered an opportunity to create an alternative picture of the mechanisms underlying sAD initiation and early progression. Looking at initiation and progression of sAD from this new angle may open for new biomarkers and novel drug targets for sAD before the appearance of the first clinical symptoms.

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

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

miRNAs as Therapeutic Tools in Alzheimer's Disease

Alzheimer's disease (AD), an age-dependent, progressive neurodegenerative disorder, is the most common type of dementia, accounting for 50-70% of all dementia cases. Due to the increasing incidence and corresponding socioeconomic burden of dementia, it has rapidly emerged as a challenge to public health worldwide. The characteristics of AD include the development of extracellular amyloid-beta plaques and intracellular neurofibrillary tangles, vascular changes, neuronal inflammation, and progressive brain atrophy. However, the complexity of the biology of AD has hindered progress in elucidating the underlying pathophysiological mechanisms of AD, and the development of effective treatments. MicroRNAs (miRNAs, which are endogenous, noncoding RNAs of approximately 22 nucleotides that function as posttranscriptional regulators of various genes) are attracting attention as powerful tools for studying the mechanisms of diseases, as they are involved in several biological processes and diseases, including AD. AD is a multifactorial disease, and several reports have suggested that miRNAs play an important role in the pathological processes of AD. In this review, the basic biology of miRNAs is described, and the function and physiology of miRNAs in the pathological processes of AD are highlighted. In addition, the limitations of current pharmaceutical therapies for the treatment of AD and the development of miRNA-based next-generation therapies are discussed.

MicroRNA-124: A Key Player in Microglia-Mediated Inflammation in Neurological Diseases

Neurological disorders are mainly characterized by progressive neuron loss and neurological deterioration, which cause human disability and death. However, many types of neurological disorders have similar pathological mechanisms, including the neuroinflammatory response. Various microRNAs (miRs), such as miR-21, miR-124, miR-146a, and miR-132 were recently shown to affect a broad spectrum of biological functions in the central nervous system (CNS). Microglia are innate immune cells with important roles in the physiological and pathological activities of the CNS. Recently, abnormal expression of miR-124 was shown to be associated with the occurrence and development of various diseases in CNS via regulating microglia function. In addition, miR-124 is a promising biomarker and therapeutic target. Studies on the role of miR-124 in regulating microglia function involved in pathogenesis of neurological disorders at different stages will provide new ideas for the use of miR-124 as a therapeutic target for different CNS diseases.

miRNA-124-3p targeting of LPIN1 attenuates inflammation and apoptosis in aged male rats cardiopulmonary bypass model of perioperative neurocognitive disorders

Perioperative neurocognitive disorder (PND) is recently recommended to define the cognitive decrease during the perioperative period. However, the disease's underlying mechanisms remain unclear. MicroRNAs (miRNAs) are noncoding RNAs that play a vital role in regulating neuroregeneration and neuronal apoptosis. In this study, miR-124-3p was significantly reduced in the PND rat model after a cardiopulmonary bypass (CPB) procedure. MicroRNA-124 (miR-124)-3p-overexpressed lentivirus was constructed and injected via the intracerebroventricular method before CPB. Morris Water Maze test (WMW) and the Open-Field test (OFT) were used to measure behavior changes, data shows decline of cognitive function of rats after CPB. PND rats expressed higher Aβ and p-Tau Protein by using immunohistochemistry (IHC) analyses and Enzyme-Linked Immune Sorbent Assay (ELISA). Moreover, the results of IHC, ELISA, Western Blot analysis (WB) and Terminal-deoxynucleotidyl Transferase Mediated Nick End Labeling Assay (TUNEL) showed CPB procedure induced inflammation and apoptosis in rats with PND. The data also revealed the protective function of miR-124-3p overexpression against PND in relieving inflammation, cell apoptosis, and alleviating repaired cognitive function. Moreover, miR-124-3p was predicted by directly targeting LPIN1. This study gives a novel viewpoint that miR-124-3p could improve the state of PND via modulating LPIN1, therefore providing a new strategy for preventing and treating PND in a preclinical application.

Neuronal Dynamics and miRNA Signaling Differ between SH-SY5Y APPSwe and PSEN1 Mutant iPSC-Derived AD Models upon Modulation with miR-124 Mimic and Inhibitor

Neuronal miRNA dysregulation may have a role in the pathophysiology of Alzheimer's disease (AD). miRNA(miR)-124 is largely abundant and a critical player in many neuronal functions. However, the lack of models reliably recapitulating AD pathophysiology hampers our understanding of miR-124's role in the disease. Using the classical human SH-SY5Y-APP695 Swedish neuroblastoma cells (SH-SWE) and the PSEN1 mutant iPSC-derived neurons (iNEU-PSEN), we observed a sustained upregulation of miR-124/miR-125b/miR-21, but only miR-124 was consistently shuttled into their exosomes. The miR-124 mimic reduced APP gene expression in both AD models. While miR-124 mimic in SH-SWE neurons led to neurite outgrowth, mitochondria activation and small Aβ oligomer reduction, in iNEU-PSEN cells it diminished Tau phosphorylation, whereas miR-124 inhibitor decreased dendritic spine density. In exosomes, cellular transfection with the mimic predominantly downregulated miR-125b/miR-21/miR-146a/miR-155. The miR-124 inhibitor upregulated miR-146a in the two experimental cell models, while it led to distinct miRNA signatures in cells and exosomes. In sum, though miR-124 function may be dependent on the neuronal AD model, data indicate that keeping miR-124 level strictly controlled is crucial for proper neuronal function. Moreover, the iNEU-PSEN cellular model stands out as a useful tool for AD mechanistic studies and perhaps for the development of personalized therapeutic strategies.

New RNA-Based Breakthroughs in Alzheimer's Disease Diagnosis and Therapeutics

Dementia is described as the fifth leading cause of death worldwide and Alzheimer’s disease (AD) is recognized as the most common, causing a huge impact on health costs and quality of patients’ lives. The main hallmarks that are commonly associated with the pathologic process are amyloid deposition, pathologic Tau phosphorylation and neurodegeneration. It is still unclear how these events are linked to the disease progression, due to the complex pathologic mechanisms. Nevertheless, several hypotheses have been proposed for a better understanding of AD. The AD diagnosis is performed by using a combination of several tools to detect β-amyloid peptide (Aβ) deposits and modifications in cognitive performance, sometimes being expensive and invasive. In the treatment field, there is still an absence of effective treatments to delay or stop the progression of the disease, with most of the approved drugs used to relieve symptoms, and all of them with significant adverse side effects. Considering all limitations, the need to establish new and more effective diagnostic and therapeutic strategies becomes clear. This review aims not only to describe the disease and its impact but also to collect the currently available diagnostic and therapeutic strategies, highlighting new promising RNA-based strategies for AD.

miR-124-3p Inhibits Microglial Secondary Inflammation After Basal Ganglia Hemorrhage by Targeting TRAF6 and Repressing the Activation of NLRP3 Inflammasome

Objectives: Intracerebral hemorrhage (ICH) represents a serious central nervous system emergency with high morbidity and mortality, and the basal ganglia is the most commonly affected brain region. Differentially expressed microRNAs (miRs) have recently been highlighted to serve as potential diagnostic biomarkers and therapeutic targets for ICH. This study investigated the mechanism of miR-124-3p in microglial secondary inflammation after ICH.

Methods: In this study, 48 patients with primary basal ganglia ICH and 48 healthy volunteers were selected and venous blood was collected from all patients on the second morning of admission (within 24 h of stroke onset). The expression of miR-124-3p in serum was detected by RT-qPCR. Three months after ICH, the patients were assessed by modified Rankin Scale (mRS), and the correlation between miR-124-3p expression and mRS score was analyzed by Pearson. The inflammatory response of microglia was induced by lipopolysaccharide (LPS) to establish the cell model of microglial inflammation. miR-124-3p expression patterns were detected in the serum of ICH patients and healthy volunteers, normal microglia, and LPS-induced microglia. The miR-124-3p mimic was transfected into LPS-induced microglia, followed by measurement of the inflammatory factors, apoptosis rate, and cell viability. The target gene of miR-124-3p was predicted and verified. The expression patterns of tumor necrosis factor receptor-associated factor 6 (TRAF6) were detected. pcDNA3.1 and pcDNA3.1-TRAF6 were transfected into LPS-induced HMC3 cells, and nucleotide-binding oligomerization domain-like receptor (NLR) pyrin domain-containing 3 (NLRP3) expression patterns were determined. Lastly, the effects of TRAF6 overexpression on apoptosis, cell viability, and inflammation in HMC3 cells were measured.

Results: miR-124-3p was downregulated in the serum of basal ganglia ICH patients and LPS-induced microglia, and miR-124-3p expression was negatively correlated with mRS. Overexpression of miR-124-3p reduced the inflammatory factors and apoptosis rate and promoted cell activity in LPS-induced microglia. miR-124-3p was found to target TRAF6. Overexpression of TRAF6 enhanced the expression of NLRP3 inflammasome, inflammatory factors and apoptosis rate, and reduced cell viability.

Conclusion: Our findings indicate that miR-124-3p repressed the activation of NLRP3 inflammasome by targeting TRAF6, thus inhibiting microglial secondary inflammation after ICH in basal ganglia.

MicroRNA-124-3p inhibits the differentiation of precartilaginous stem cells into nucleus pulposus-like cells via targeting FSTL1

MicroRNA (miRNA/miR)-124-3p has been extensively studied in tumor biology and stem cells. However, little is known regarding its functional roles in the differentiation of precartilaginous stem cells (PSCs) into nucleus pulposus-like cells (NPLCs). In the present study, using miRNA microarray screening, it was demonstrated that the miRNA expression profiles differed between rat primary PSCs and TGF-β1-induced differentiated NPLCs, and that miR-124-3p was significantly differentially expressed during the differentiation of PSCs to NPLCs. Furthermore, RT-qPCR analysis verified that miR-124-3p expression was decreased during PSC differentiation, with the lowest levels being detected at the later stages. Subsequent experiments revealed that miR-124-3p overexpression significantly decreased the expression of the extracellular matrix proteins, aggrecan and collagen type II, which was accompanied by a significant decrease in follistatin-related protein 1 (FSTL1) expression levels. Moreover, bioinformatics analysis indicated that FSTL1 was a potential target of miR-124-3p, which was additionally verified using luciferase reporter assays. Taken together, these data revealed a specific regulatory pathway of miR-124-3p, which negatively regulated its target gene, FSTL1, during the differentiation of PSCs to NPLCs, and suggested a functional role for miR-124-3p in the differentiation of PSCs.

Key Disease Mechanisms Linked to Alzheimer's Disease in the Entorhinal Cortex

Alzheimer’s disease (AD) is a chronic, neurodegenerative brain disorder affecting millions of Americans that is expected to increase in incidence with the expanding aging population. Symptomatic AD patients show cognitive decline and often develop neuropsychiatric symptoms due to the accumulation of insoluble proteins that produce plaques and tangles seen in the brain at autopsy. Unexpectedly, some clinically normal individuals also show AD pathology in the brain at autopsy (asymptomatic AD, AsymAD). In this study, SWItchMiner software was used to identify key switch genes in the brain’s entorhinal cortex that lead to the development of AD or disease resilience. Seventy-two switch genes were identified that are differentially expressed in AD patients compared to healthy controls. These genes are involved in inflammation, platelet activation, and phospholipase D and estrogen signaling. Peroxisome proliferator-activated receptor γ (PPARG), zinc-finger transcription factor (YY1), sterol regulatory element-binding transcription factor 2 (SREBF2), and early growth response 1 (EGR1) were identified as transcription factors that potentially regulate switch genes in AD. Comparing AD patients to AsymAD individuals revealed 51 switch genes; PPARG as a potential regulator of these genes, and platelet activation and phospholipase D as critical signaling pathways. Chemical–protein interaction analysis revealed that valproic acid is a therapeutic agent that could prevent AD from progressing.

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.

An update on the role of miR-124 in the pathogenesis of human disorders

MicroRNA-124 (miR-124) is a copious miRNA in the brain, but it is expressed in a wide range of human/animal tissues participating in the pathogenesis of several disorders. Based on its important function in the development of the nervous system, abnormal expression of miR-124 has been detected in nervous system diseases including Alzheimer's disease, Parkinson's disease, Hypoxic-Ischemic Encephalopathy, Huntington's disease, and ischemic stroke. In addition to these conditions, miR-124 contributes to the pathogenesis of cardiovascular disorders, hypertension, and atherosclerosis. Besides, it has been shown to be down-regulated in a wide range of human cancers such as colorectal cancer, breast cancer, gastric cancer, glioma, pancreatic cancer, and other types of cancer. Yet, few studies have reported upregulation of miR-124 in some cancer types. In the current study, we describe the role of miR-124 in these malignant and non-malignant conditions.

miR-124-3p Ameliorates Isoflurane-Induced Learning and Memory Impairment via Targeting STAT3 and Inhibiting Neuroinflammation

INTRODUCTION

Substantial evidence has indicated that isoflurane leads to learning and memory impairment. This study was designed to investigate the potential role of microRNA-124-3p (miR-124-3p) in isoflurane-induced learning and memory impairment in rats.

METHODS

Spatial learning and memory of rats were estimated by the Morris water maze (MWM) test after the construction of isoflurane-treated models. qRT-PCR was performed to assess the expression levels of miR-124-3p. The levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α in the hippocampal tissues were determined by enzyme-linked immunosorbent assay. The luciferase activity was determined by using a dual-luciferase reporter assay system.

RESULTS

The higher escape latency and lower time spent in the original quadrant were shown in isoflurane-treated rats compared with the control rats. Moreover, treatment with isoflurane could induce neuroinflammation, and miR-124-3p was poorly expressed in the hippocampal tissue of isoflurane-treated rats. Furthermore, STAT3 is a functional target of miR-124-3p, and inflammatory cytokine level was downregulated by miR-124-3p.

DISCUSSION/CONCLUSION

Combining the results of the current study demonstrates that miR-124-3p may have pivotal roles in improving isoflurane-induced learning and memory impairment via targeting STAT3 and inhibiting neuroinflammation.