The biomarker and therapeutic potential of miRNA in Alzheimer's disease

microRNA Profile Changes in Brain, Cerebrospinal Fluid, and Blood Following Low-Level Repeated Blast Exposure in a Rat Model

It is well documented that service members are exposed to repeated low-level blast overpressure during training with heavy weapons such as artillery, mortars and explosive breaching. Often, acute symptoms associated with these exposures are transient but cumulative effect of low-level repeated blast exposures (RBEs) can include persistent deficits in cognitive and behavioral health. Thus far, reliable diagnostic biomarkers which can guide countermeasure strategies have not been identified. In this study, rats were exposed to multiple field-relevant blast waves with 8.5 and 10 psi peak positive overpressures, applying one exposure per day for 14 consecutive days. micro-RNAs that can potentially be used as biomarkers for RBEs were assessed in blood, brain, and cerebrospinal fluid (CSF). RBE caused a differential pattern of changes in various miRNAs in blood, brain and CSF in an overpressure-dependent manner. Our key outcomes were decrease of mir-6215 and let-7 family miRNAs and increase of mir-6321 and mir-222-5p in brain, blood, and CSF. Expression pattern of these miRNAs is in concurrence with various neurological conditions such as upregulation of mir-6321 in focal ischemic injury and downregulation of mir-6215 in nerve injury model. Contrarily, Let-7 family miRNAs have neuroprotective role and their downregulation suggests progression of blast induced traumatic brain injury (bTBI) with RBE at 14× -8.5 psi. Repeated blast caused alterations in miRNAs that are likely involved in vascular integrity, inflammation, and cell death. These results indicate that miRNAs are differentially dysregulated in response to blast injuries and may represent better prognostic and diagnostic biomarkers than traditional molecules to identify blast-specific brain injury.

miRNA375-3p/rapamycin mediates the mTOR pathway by decreasing PS1, enhances microglial cell activity to regulate autophagy in Alzheimer's disease

The clinical prevention, diagnosis, treatment, and drug development of Alzheimer's disease (AD) require urgent detection of novel targets and methods. Autophagy and microglia are significantly associated with the pathogenesis of early AD. This study indicated that microRNA-375-3p can inhibit autophagy by promoting mTOR phosphorylation in normal physiological conditions, while microRNA-375-3p promoted autophagy and enhanced neural repair by inhibiting the expression of presenilin 1 in early AD pathogenesis. Furthermore, co-treatment of rapamycin, and microRNA-375-3p can synergistically promote the autophagy and microglial activation in a neuroprotective manner, clear Aβ accumulation, repair nerve damage, and alleviate cognitive dysfunction and memory defects in APP/PS1 TG mice. This research revealed the impact and mechanism of miR375-3p on the early stage of AD through in vivo and in vitro experiments and provides new ideas and directions for the early treatment of AD.

Genetic Factors and MicroRNAs in the Development of Gallbladder Cancer: The Prospective Clinical Targets

Gallbladder cancer (GBC) is an uncommon condition in which malignant (cancer) cells are detected in gallbladder tissue. Cancer is often triggered when normal cells turn malignant and begin to spread. Cancer can also be caused by genetic anomalies that result in uncontrolled cell proliferation and tumor development. MicroRNAs (also known as miRNAs or miRs) are a group of small, endogenous, non-coding RNAs of 19-23 nucleotides in length, which play a key role in post-transcriptional gene regulation. These miRNAs serve as negative gene regulators by supervising target genes and regulating biological processes, including cell proliferation, migration, invasion, and apoptosis. Cancer development and progression relate to aberrant miRNA expression. This review demonstrated the implication of various genetic factors and microRNAs in developing and regulating GBC. This suggests the potential of genes and RNAs as the diagnostic, prognostic, and therapeutic targets in gallbladder cancer.

Discerning the Prospects of miRNAs as a Multi-Target Therapeutic and Diagnostic for Alzheimer's Disease

Although over the last few decades, numerous attempts have been made to halt Alzheimer's disease (AD) progression and mitigate its symptoms, only a few have been proven beneficial. Most medications available, still only cater to the symptoms of the disease rather than fixing the cause at the root level. A novel approach involving the use of miRNAs, which work on the principle of gene silencing, is being explored by scientists. Naturally present miRNAs in the biological system help to regulate various genes than may be implicated in AD-like BACE-1 and APP. One miRNA thus, holds the power to keep a check on several genes, conferring it the ability to be used as a multi-target therapeutic. With aging and the onset of diseased pathology, dysregulation of these miRNAs is observed. This flawed miRNA expression is responsible for the unusual buildup of amyloid proteins, fibrillation of tau proteins in the brain, neuronal death and other hallmarks leading to AD. The use of miRNA mimics and miRNA inhibitors provides an attractive perspective for fixing the upregulation and downregulation of miRNAs that led to abnormal cellular activities. Furthermore, the detection of miRNAs in the CSF and serum of diseased patients might be considered an earlier biomarker for the disease. While most of the therapies designed around AD have not succeeded completely, the targeting of dysregulated miRNAs in AD patients might give a new direction to scholars to develop an effective treatment for Alzheimer's disease.

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.

Role of miRNAs in Neurodegeneration: From Disease Cause to Tools of Biomarker Discovery and Therapeutics

Neurodegenerative diseases originate from neuronal loss in the central nervous system (CNS). These debilitating diseases progress with age and have become common due to an increase in longevity. The National Institute of Environmental Health Science’s 2021 annual report suggests around 6.2 million Americans are living with Alzheimer’s disease, and there is a possibility that there will be 1.2 million Parkinson’s disease patients in the USA by 2030. There is no clear-cut universal mechanism for identifying neurodegenerative diseases, and therefore, they pose a challenge for neurobiology scientists. Genetic and environmental factors modulate these diseases leading to familial or sporadic forms. Prior studies have shown that miRNA levels are altered during the course of the disease, thereby suggesting that these noncoding RNAs may be the contributing factor in neurodegeneration. In this review, we highlight the role of miRNAs in the pathogenesis of neurodegenerative diseases. Through this review, we aim to achieve four main objectives: First, we highlight how dysregulation of miRNA biogenesis led to these diseases. Second, we highlight the computational or bioinformatics tools required to identify the putative molecular targets of miRNAs, leading to biological molecular pathways or mechanisms involved in these diseases. Third, we focus on the dysregulation of miRNAs and their target genes leading to several neurodegenerative diseases. In the final section, we highlight the use of miRNAs as potential diagnostic biomarkers in the early asymptomatic preclinical diagnosis of these age-dependent debilitating diseases. Additionally, we discuss the challenges and advances in the development of miRNA therapeutics for brain targeting. We list some of the innovative strategies employed to deliver miRNA into target cells and the relevance of these viral and non-viral carrier systems in RNA therapy for neurodegenerative diseases. In summary, this review highlights the relevance of studying brain-enriched miRNAs, the mechanisms underlying their regulation of target gene expression, their dysregulation leading to progressive neurodegeneration, and their potential for biomarker marker and therapeutic intervention. This review thereby highlights ways for the effective diagnosis and prevention of these neurodegenerative disorders in the near future.

RNA Therapeutics - Research and Clinical Advancements

RNA therapeutics involve the use of coding RNA such as mRNA as well as non-coding RNAs such as small interfering RNAs (siRNA), antisense oligonucleotides (ASO) to target mRNA, aptamers, ribozymes, and clustered regularly interspaced short palindromic repeats-CRISPR-associated (CRISPR/Cas) endonuclease to target proteins and DNA. Due to their diverse targeting ability and research in RNA modification and delivery systems, RNA-based formulations have emerged as suitable treatment options for many diseases. Therefore, in this article, we have summarized different RNA therapeutics, their targeting strategies, and clinical progress for various diseases as well as limitations; so that it might help researchers formulate new and advanced RNA therapeutics for various diseases. Additionally, U.S. Food and Drug Administration (USFDA)-approved RNA-based therapeutics have also been discussed.

miR-584 and miR-146 are candidate biomarkers for acute respiratory distress syndrome

MicroRNAs (miRNAs/miRs) have important roles in inflammation and infections, which are common manifestations of acute respiratory distress syndrome (ARDS). The present study aimed to assess whether serum miRNAs are potential diagnostic biomarkers for human ARDS. For this, two sets of serum samples from healthy individuals and patients with ARDS were analysed by high-throughput sequencing to identify differentially expressed genes in ARDS. A total of 679 valid sequences were identified as differentially expressed (P<0.05). Of these, five differentially expressed miRNAs were subjected to reverse transcription-quantitative PCR validation. Finally, two miRNAs (miR-584 and miR-146a) were successfully verified. These two miRNAs were significantly downregulated in the serum of patients with ARDS. Gene Ontology annotations and Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that their target transcripts were implicated in a broad range of biological processes and various metabolic pathways, including involvement in the regulation of various inflammatory factors. The present study provided a framework for understanding the molecular mechanisms of ARDS and suggested that miR-584 and miR-146a are associated with ARDS and may be potential therapeutic targets.

MiR-330-3p and miR-485-5p as biomarkers for glioblastoma: An integrated bioinformatics and experimental study

Glioblastoma Multiforme (GBM) is the most common, invasive, and malignant primary brain tumor with a poor prognosis and a median survival of 12-15 months. This study tried to identify the most significant miRNA biomarkers in both tissue and serum samples of GBM. GSE25632 was employed from gene expression omnibus and using WGCNA package, association of miRNA networks and clinical data was explored and brown and green modules identified as the most relevant modules. Independently, Limma package was utilized to identify differentially expressed miRNAs (DEMs) in GSE25632 by cutoff logFC > 2 and P.value < 0.05. By merging the results of Limma and WGCNA, the miRNAs that were in brown and green modules and had mentioned cutoff were selected as hub miRNAs. Performing enrichment analysis, Pathways in cancer, Prostate cancer, Glioma, p53 signaling pathway, and Focal adhesion were identified as the most important signaling pathways. Based on miRNA- target genes, has-mir-330-3p and has-mir-485-5p were identified as core miRNAs. The expression level of core miRNAs was validated by GSE90604, GSE42657, and GSE93850. We evaluated the expression level of common target genes of two detected core genes based on GSE77043, GSE42656, GSE22891, GSE15824, and GSE122498. The ability of detected miRNAs to discriminate GBM from healthy controls was assessed by area under the curve (AUC) using the ROC curve analysis. Based on TCGA database, we tested the prognostic significance of miRNAs using overall survival analysis. We evaluated the expression level of the miRNAs in tissue of 83 GBM patients and also non-tumoral adjacent (as control) tissues. We used serum samples of 34 GBM patients to evaluate the expression levels of the hub miRNAs compare to the controls. Our results showed that has-mir-330-3p and has-mir-485-5p could be potential biomarkers in GBM.

The Role of HSA21 Encoded Mirna in Down Syndrome Pathophysiology:Opportunities in miRNA-Targeted Pharmacotherapy and Diagnosis of the Down Syndrome

Trisomy 21 is the most prevalent aneuploidy disorder among live-born children worldwide. Itresults from the presence of an extra copy of chromosome 21 which leads to a wide spectrum ofpathophysiological abnormalities and intellectual disabilities. Nevertheless human chromosome21 (HSA21) possess protein non-coding regions where HAS-21 derived-microRNA genes aretranscribed from. In turn, these HSA21-derived miRNAs curb protein translation of severalgenes which are essential to meet memory and cognitive abilities. From the genetics andmolecular biology standpoints, dissecting the mechanistic relationship between DS pathology/symptoms and five chromosome 21-encoded miRNAs including miR-99a, let-7c, miR-125b-2,miR-155 and miR-802 seems pivotal for unraveling novel therapeutic targets. Recently,several studies have successfully carried out small molecule inhibition of miRNAs function,maturation, and biogenesis. One might assume in the case of DS trisomy, the pharmacologicalinhibition of these five overexpressed miRNAs might open new avenues for amelioration of theDS symptoms and complications. In this review, we primarily elucidated the role of HSA21-encoded miRNAs in the DS pathology which in turn introduced and addressed importanttherapeutic targets. Moreover, we reviewed relevant pharmaceutical efforts that based theirgoals on inhibition of these pathological miRNAs at their different biogenesis steps. We havealso discussed the challenges that undermine and question the reliability of miRNAs as noneinvasivebiomarkers in prenatal diagnosis.

MicroRNA-20b-5p aggravates neuronal apoptosis induced by β-Amyloid via down-regulation of Ras homolog family member C in Alzheimer's disease

Recent studies have reported that microRNAs are abnormally expressed in brain tissues of Alzheimers disease (AD) patients. However, the accurate function of miR-20b-5p in AD has not been elucidated. We intended to investigate the role and underlying mechanism of miR-20b-5p in AD. The expression of miR-20b-5p was increased, and the expression of RhoC was decreased in the hippocampus of Appswe/PS△E 9 mice. In order to construct a cell model in vitro to study the underlying action mechanism, PC12 cells were treated with Aβ_25-35. The cell apoptosis detected by flow cytometry and the expression of cleaved-caspase-3 detected by western blot were both remarkably increased in PC12 cells treated with Aβ_25-35, but they were reduced by miR-20b-5p inhibitor. In addition, MTT test showed that the cell survival rate in Aβ_25-35 + miR-20b-5p inhibitor group was higher than that in Aβ_25-35 + NC inhibitor group. Double luciferase reporter gene analysis confirmed that the binding site of miR-20b-5p was in 3'- UTR of RhoC mRNA. Knockdown of RhoC increased neuronal apoptosis induced by Aβ25-35 and the expression of cleaved-caspase-3, while miR-20b-5p inhibitor reversed these effects. Knockdown of RhoC aggravated the inhibition effect on cell viability induced by Aβ_25-35, while miR-20b-5p inhibitor diminished these effects. In conclusion, inhibition of miR-20b-5p attenuates apoptosis induced by Aβ_25-35 in PC12 cells through targeting RhoC. Therefore, miR-20b-5p may be a perspective curative target for AD.

MiR-485-3p serves as a biomarker and therapeutic target of Alzheimer's disease via regulating neuronal cell viability and neuroinflammation by targeting AKT3

BACKGROUND

Numerous microRNAs (miRNAs) have been identified as functional molecules in Alzheimer's disease (AD) pathogenesis. This study aimed to investigate the diagnostic value of microRNA-485-3p (miR-485-3p) in AD patients, evaluate the effect of miR-485-3p on neuronal viability and neuroinflammation, as well as the underlying molecular mechanisms.

METHODS

Quantitative Real-Time PCR was used to estimate expression of miR-485-3p and AKT3. A ROC analysis was used to evaluate the diagnostic value of miR-485-3p. The correlation of miR-485-3p with patients' MMSE score and inflammatory response was analyzed. Using Aβ-treated SH-SY5Y and BV2 cells models, the effects of miR-485-3p on neuronal proliferation, apoptosis, and neuroinflammation were explored. A luciferase reporter assay was used to confirm the target gene of miR-485-3p in both SH-SY5Y and BV2 cells.

RESULTS

Serum miR-485-3p expression was significantly upregulated in AD patients and cell models, which had a high diagnostic accuracy and correlated with MMSE score and inflammatory response in AD patients. The knockdown of miR-485-3p in SH-SY5Y and BV2 cells was found to significantly reverse the effect of Aβ treatment on neuronal viability and neuroinflammation. AKT3 was determined as a target of miR-485-3p, which might mediate the biological function of miR-485-3p in AD pathogenesis.

CONCLUSION

All the data indicated that increased serum miR-485-3p serves as a diagnostic biomarker in AD patients, and knockdown of miR-485-3p exerts a neuroprotective role by improving neuronal viability and weakening neuroinflammation, which may be mediated by AKT3. This study may provide a novel biomarker and therapeutic target for AD therapy.

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

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

Inhibition of microRNA-155 Alleviates Cognitive Impairment in Alzheimer's Disease and Involvement of Neuroinflammation

BACKGROUND

Neuroinflammation has important effects on cognitive functions in the pathophysiological process of Alzheimer's Disease (AD). In the current report, we determined the effects of microRNA-155 (miR-155) on the levels of IL-1β, IL-6 and TNF-α, and their respective receptors in the hippocampus using a rat model of AD.

METHODS

Real-time RT-PCR, ELISA and western blot analysis were used to examine the miR-155, PICs and PIC receptors. The Morris water maze and spatial working memory tests were used to assess cognitive functions.

RESULTS

miR-155 was increased in the hippocampus of AD rats, accompanied by amplification of IL-1β, IL-6 and TNF-α. Intracerebroventricular infusion of miR-155 inhibitor, but not its scramble attenuated the increases of IL-1β, IL-6 and TNF-α and upregulation of their receptors. MiR-155 inhibitor also attenuated upregulation of apoptotic Caspase-3 in the hippocampus of AD rats. Notably, inhibition of miR- 155 or PIC receptors largely recovered the impaired learning performance in AD rat.

CONCLUSION

We showed the critical role of miR-155 in regulating the memory impairment in AD rats likely via engagement of neuroinflammatory mechanisms, suggesting that miR-155 and its signaling molecules may present prospects in preventing and/or improving the development of the impaired cognitive functions in AD.

Extraction of Small RNAs by Titanium Dioxide Nanofibers

MicroRNAs (miRNAs) are small RNAs, that bind to mRNA targets and regulate their translation. Functional study of miRNAs and exploration of their utility as disease markers require miRNA extraction from biological samples, which contain large amounts of interfering compounds for downstream RNA identification and quantification. The most common extraction methods employ either silica columns or TRIzol reagent, but these approaches afford low recovery for small RNAs, possibly due to their short strand lengths. Here, we describe the fabrication of titanium dioxide nanofibers and the optimal extraction conditions to improve miRNA recovery from biological buffers, cell lysate, and serum.

Current Status of microRNA-Based Therapeutic Approaches in Neurodegenerative Disorders

MicroRNAs (miRNAs) are a key gene regulator and play essential roles in several biological and pathological mechanisms in the human system. In recent years, plenty of miRNAs have been identified to be involved in the development of neurodegenerative disorders (NDDs), thus making them an attractive option for therapeutic approaches. Hence, in this review, we provide an overview of the current research of miRNA-based therapeutics for a selected set of NDDs, either for their high prevalence or lethality, such as Alzheimer's, Parkinson's, Huntington's, Amyotrophic Lateral Sclerosis, Friedreich's Ataxia, Spinal Muscular Atrophy, and Frontotemporal Dementia. We also discuss the relevant delivery techniques, pertinent outcomes, their limitations, and their potential to become a new generation of human therapeutic drugs in the near future.

Single-Measurement Multiplexed Quantification of MicroRNAs from Human Tissue Using Catalytic Hairpin Assembly and Förster Resonance Energy Transfer

Absolute quantification of microRNAs (miRNAs) or other nucleic acid biomarkers is an important requirement for molecular and clinical biosensing. Emerging technologies with beneficial features concerning simplicity and multiplexing present an attractive route for advancing diagnostic tools toward rapid and low-cost bioanalysis. However, the actual translation into the clinic by miRNA quantification in human samples is often missing. Here, we show that implementing time-gated Förster resonance energy transfer (TG-FRET) into a catalytic hairpin assembly (CHA) can be used for the simultaneous quantification of two miRNAs with a single measurement from total RNA extracts of human tissues. A single terbium-dye FRET pair was conjugated at two specific distances within target-specific CHA hairpin probes, such that each miRNA resulted in distinct amplified photoluminescence (PL) decays that could be distinguished and quantified by TG PL intensity detection. Enzyme-free amplification in a separation-free assay format and the absence of autofluorescence background allowed for simple, specific, and sensitive detection of miR-21 and miR-20a with limits of detection down to 1.8 pM (250 amol). Reliable duplexed quantification of both miRNAs at low picomolar concentrations was confirmed by analyzing total RNA extracts from different colon and rectum tissues with single- and dual-target CHA-TG-FRET and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) for comparison. These simple and multiplexed nucleic acid biomarker assays present a capable method for clinical diagnostics and biomolecular research.

Exosomal miR-21/Let-7a ratio distinguishes non-small cell lung cancer from benign pulmonary diseases

Aim

To assess the exosomal miR‐21/Let‐7a ratio, a noninvasive method, in distinguishing non‐small cell lung cancer (NSCLC) from benign pulmonary diseases.

Methods

The exosomes were extracted from the peripheral blood serum using serum exosomal extraction kit. miR‐21 and Let‐7a levels were evaluated by quantitative reverse transcription polymerase chain reaction.

Results

We found that miR‐21/Let‐7a ratio of NSCLC patients was significantly higher than that of healthy people, patients with pulmonary inflammation diseases, and benign pulmonary nodules, respectively. Receiver‐operating characteristic analysis revealed that as compared with healthy controls, miR‐21/Let‐7a produced the area under the curve (AUC) at 0.8029 in patients with NSCLC, which helped to distinguish NSCLC from healthy controls with 81.33% sensitivity and 69.57% specificity. In addition, the AUC of miR‐21/Let‐7a in NSCLC patients was 0.8196 in comparison to patients with pulmonary inflammation diseases. Meanwhile, the sensitivity and specificity were 56.00% and 100%, respectively. Furthermore, compared with patients with benign pulmonary nodules, the AUC of miR‐21/Let‐7a in NSCLC patients was 0.7539. The sensitivity and specificity were 56.00% and 82.61%, respectively.

Conclusion

In the present study, our findings revealed that exosomal miR‐21/Let‐7a ratio holds considerable promise as a noninvasive biomarker for the diagnosis of NSCLC from benign pulmonary diseases.

MiR-539-5p Decreases amyloid β-protein production, hyperphosphorylation of Tau and Memory Impairment by Regulating PI3K/Akt/GSK-3β Pathways in APP/PS1 Double Transgenic Mice

The production of amyloid β (Aβ) and tau hyperphosphorylation have been identified as key processes in Alzheimer's disease (AD) pathogenesis. MiR-539-5p has been found to be abnormally expressed in brain tissue; however, the functional role of miR-539-5p in the pathogenesis of AD remains unclear. In our study, we found that the expression of miR-539-5p was significantly downregulated in humans and mice with AD and was negatively correlated with expression of APP, caveolin 1, and GSK-3β. Moreover, upregulation of miR-539-5p inhibited Aβ accumulation, tau phosphorylation, oxidative stress, and apoptosis and improved memory ability in AD mice. Furthermore, by using bioinformatics tool and dual-luciferase reporter assay, APP, Caveolin 1, and GSK-3β were confirmed as direct targets of miR-539-5p. In addition, the PI3K/AKT/GSK-3β signaling pathway can be regulated by miR-539-5p. In conclusion, this study provided a novel insight into the pathologic mechanism of AD by identifying that miR-539-5p plays a neuroprotective role in AD.

STAT4-mediated down-regulation of miR-3619-5p facilitates stomach adenocarcinoma by modulating TBC1D10B

BACKGROUND

MicroRNAs (miRNAs) as the subtype of non-coding RNAs are revealed to be crucial players in cellular activities. It has been reported that miR-3619-5p functions as a tumor inhibitor in several cancers. However, the connection between miR-3619-5p and stomach adenocarcinoma (STAD) remains to be discovered.

AIM OF THE STUDY

The purpose of the study is to figure out the role and molecular regulation mechanism of miR-3619-5p in STAD.

METHODS

The expression of miR-3619-5p was evaluated via qRT-PCR analysis. Gain-of-function experiments demonstrated the effects of miR-3619-5p on cellular functions. The upper-stream transcription factor STAT4 and downstream target gene TBC1D10B of miR-3619-5p were identified by bioinformatic analysis. The binding and interaction between the indicated molecules were verified by RNA pull-down and luciferase reporter assays.

RESULTS

The expression of miR-3619-5p was prominently down-regulated in STAD cells and tissues. MiR-3619-5p suppresses cell proliferation, migration, invasion and tumor growth in STAD. Further, STAT4 bound with miR-3619-5p promoter and inhibited its transcription. MiR-3619-5p was also recognized to modulate STAD progression through the regulation of downstream target gene TBC1D10B.

CONCLUSION

STAT4-mediated miR-3619-5p controls STAD carcinogenesis and progression through modulating TBC1D10B expression, which may provide a novel insight for researching the STAD-related molecular mechanism.

EVmiRNA: a database of miRNA profiling in extracellular vesicles

Extracellular vesicles (EVs), such as exosomes and microvesicles, acted as cell-to-cell communication vectors and potential biomarkers for diseases. microRNAs (miRNAs) are the most well studied molecules in EVs, thus a comprehensive investigation of miRNA expression profiles in EVs will be helpful to explore their functions and biomarkers. We curated 462 small RNA sequencing samples of EVs from 17 sources/diseases and constructed the EVmiRNA database (http://bioinfo.life.hust.edu.cn/EVmiRNA) to show the miRNA expression profiles. We found >1000 miRNAs expressed in these EVs and detected specific miRNAs for EVs of each source/disease. EVmiRNA provides three functional modules: (i) the miRNA expression profiles and the sample information of EVs from different sources (such as blood, breast milk etc.); (ii) the specifically expressed miRNAs in different EVs that would be helpful for biomarker identification; (iii) the miRNA annotations including the miRNA expression in EVs and TCGA cancer types, miRNA pathway regulations as well as miRNA function and publications. EVmiRNA has a user-friendly web interface with powerful browse and search functions, as well as data downloading. It is the first database focusing on miRNA expression profiles in EVs and will be useful for the research and application community of EV biomarker, miRNA function and liquid biopsy.

GOLPH3 Regulates Exosome miRNA Secretion in Glioma Cells

We aimed to examine whether golgi protein GOLPH3 could affect the secretion of glioma cell-derived exosomes. The exosomes were extracted by ultra-centrifugation from the supernatant of U251 and U87 cell cultures and identified by transmission electron microscopy (TEM), Malvern analyzer, and western blot. The quantity of exosomes was examined by measuring the total protein levels and the number of multiple vesicle bodies (MVBs), the source of exosomes. The exosome miRNAs were analyzed by high-throughput sequencing followed by GO and KEGG analysis, and validated by qRT-PCR. GOLPH3 could not affect the total protein levels of exosomes and the number of MVBs. However, we found 149 differentially expressed miRNAs in exosomes between vector and GOLPH3 over-expression group, and 14 miRNAs were only examined in GOLPH3 over-expression cells. The predicted target genes of these miRNAs had functions in binding and catalytic activity, which were enriched in the pathways of endocytosis, RNA transportation, thyroid hormone signaling and miRNAs in cancer. GOLPH3 could not affect the quantity of exosomes, but rather contribute to miRNA expression in exosomes, which may play some functions in the promotion effect of GOLPH3 on glioma development.

Mechanisms of Cardiovascular Disorders in Patients With Chronic Kidney Disease: A Process Related to Accelerated Senescence

Cardiovascular diseases (CVDs), especially those involving a systemic inflammatory process such as atherosclerosis, remain the leading cause of morbidity and mortality in patients with chronic kidney disease (CKD). CKD is a systemic condition affecting approximately 10% of the general population. The prevalence of CKD has increased over the past decades because of the aging of the population worldwide. Indeed, CVDs in patients with CKD constitute a premature form of CVD observed in the general population. Multiple studies indicate that patients with renal disease undergo accelerated aging, which precipitates the appearance of pathologies, including CVDs, usually associated with advanced age. In this review, we discuss several aspects that characterize CKD-associated CVDs, such as etiopathogenic elements that CKD patients share with the general population, changes in the cellular balance of reactive oxygen species (ROS), and the associated process of cellular senescence. Uremia-associated aging is linked with numerous changes at the cellular and molecular level. These changes are similar to those observed in the normal process of physiologic aging. We also discuss new perspectives in the study of CKD-associated CVDs and epigenetic alterations in intercellular signaling, mediated by microRNAs and/or extracellular vesicles (EVs), which promote vascular damage and subsequent development of CVD. Understanding the processes and factors involved in accelerated senescence and other abnormal intercellular signaling will identify new therapeutic targets and lead to improved methods of diagnosis and monitoring for patients with CKD-associated CVDs.

Identification of a Diagnostic Set of Endomyocardial Biopsy microRNAs for Acute Cellular Rejection Diagnostics in Patients after Heart Transplantation Using Next-Generation Sequencing

Introduction: Acute cellular rejection (ACR) of heart allografts represents the most common reason for graft failure. Endomyocardial biopsies (EMB) are still subject to substantial interobserver variability. Novel biomarkers enabling precise ACR diagnostics may decrease interobserver variability. We aimed to identify a specific subset of microRNAs reflecting the presence of ACR. Patients and Methods: Monocentric retrospective study. A total of 38 patients with the anamnesis of ACR were identified and for each patient three consecutive samples of EMB (with, prior and after ACR) were collected. Sixteen trios were used for next-generation sequencing (exploratory cohort); the resting 22 trios were used for validation with qRT-PCR (validation cohort). Statistical analysis was performed using R software. Results: The analysis of the exploration cohort provided the total of 11 miRNAs that were altered during ACR, the three of which (miR-144, miR-589 and miR-182) were further validated in the validation cohort. Using the levels of all 11 miRNAs and principal component analysis, an ACR score was created with the specificity of 91% and sensitivity of 68% for detecting the presence of ACR in the EMB sample. Conclusion: We identified a set of microRNAs altered in endomyocardial biopsies during ACR and using their relative levels we created a diagnostic score that can be used for ACR diagnosis.

Cofilin 2 in Serum as a Novel Biomarker for Alzheimer's Disease in Han Chinese

The identification of biomarkers of Alzheimer’s disease (AD) is an important and urgent area of study, not only to aid in the early diagnosis of AD, but also to evaluate potentially new anti-AD drugs. The aim of this study was to explore cofilin 2 in serum as a novel biomarker for AD. The upregulation was observed in AD patients and different AD animal models compared to the controls, as well as in AD cell models. Memantine and donepezil can attenuate the upregulation of cofilin 2 expression in APP/PS1 mice. The serum levels of cofilin 2 in AD or mild cognitive impairment (MCI) patients were significantly higher compared to controls (AD: 167.9 ± 35.3 pg/mL; MCI: 115.9 ± 15.4 pg/mL; Control: 90.5 ± 27.1 pg/mL; p < 0.01). A significant correlation between cofilin 2 levels and cognitive decline was observed (r = –0.792; p < 0.001). The receiver operating characteristic curve (ROC) analysis showed the area under the curve (AUC) of cofilin 2 was 0.957, and the diagnostic accuracy was 80%, with 93% sensitivity and 87% specificity. The optimal cut-off value was 130.4 pg/ml. Our results indicate the possibility of serum cofilin 2 as a novel and non-invasive biomarker for AD. In addition, the expression of cofilin 2 was found to be significantly increased in AD compared to vascular dementia (VaD), and only an increased trend but not significant was detected in VaD compared to the controls. ROC analysis between AD and VaD showed that the AUC was 0.824, which could indicate a role of cofilin 2 as a biomarker in the differential diagnosis between AD and VaD.

A four serum-miRNA panel serves as a potential diagnostic biomarker of osteosarcoma

BACKGROUND

Osteosarcoma (OS) is the most common malignant bone tumor in young adults and adolescents with approximately 3 million new cases annually. Due to the lack of sensitive and specific diagnostic biomarkers, although OS patients are curable after surgical resection, many patients suffer from metastasis or recurrence. This study aimed to investigate whether circulating microRNAs (miRNAs) could serve as biomarkers for the diagnosis of OS.

MATERIALS AND METHODS

Healthy individuals and OS patients enrolled in this study came from Nanjing First Hospital. First, candidate miRNAs were selected by integrated analysis of two GEO datasets and a publicly available miRNA dataset. The expression of these miRNAs in tissues and serum samples were subsequently examined through qRT-PCR. The diagnostic utility of these differential miRNAs was examined by using receiver operating characteristic (ROC) curve analysis. Finally, the potential signaling pathways associated with candidate miRNAs were searched through online tools.

RESULTS

Four miRNAs (miR-487a, miR-493-5p, miR-501-3p and miR-502-5p) were selected to further investigate their diagnostic potential for OS. We discovered miR-487a, miR-493-5p, miR-501-3p and miR-502-5p were upregulated in OS tissues and serums. Besides, miR-487a, miR-493-5p, miR-501-3p and miR-502-5p in peripheral blood of OS patients were tumor-derived. The area under the ROC curve (AUC) was 0.83 (95% CI 0.71-0.97) for miR-487a, 0.79 (95% CI 0.66-0.93) for miR-493-5p, 0.82 (95% CI 0.68-0.95) for miR-501-3p, 0.83 (95% CI 0.72-0.95) for miR-502-5p, and 0.89 (95% CI 0.78-1.0) for miRNAs combination.

CONCLUSION

Circulating miR-487a, miR-493-5p, miR-501-3p and miR-502-5p were novel potential diagnostic biomarkers of OS.

Construction of Potential Glioblastoma Multiforme-Related miRNA-mRNA Regulatory Network

Background: Glioblastoma multiforme (GBM), the most common and aggressive human malignant brain tumor, is notorious for its limited treatment options and poor prognosis. MicroRNAs (miRNAs) are found to be involved in tumorigenesis of GBM. However, a comprehensive miRNA-mRNA regulatory network has still not been established.

Methods: A miRNA microarray dataset (GSE90603) was obtained from GEO database. Then, we employed GEO2R tool to perform differential expression analysis. Potential transcription factors and target genes of screened differentially expressed miRNAs (DE-miRNAs) were predicted. The GBM mRNA dataset were downloaded from TCGA database for identifying differentially expressed genes (DEGs). Next, GO annotation and KEGG pathway enrichment analysis was conducted. PPI network was then established, and hub genes were identified via Cytoscape software. The expression and prognostic roles of hub genes was further evaluated.

Results: Total 33 DE-miRNAs, consisting of 10 upregulated DE-miRNAs and 23 downregulated DE-miRNAs, were screened. SP1 was predicted to potentially regulate most of screened DE-miRNAs. Three thousand and twenty seven and 3,879 predicted target genes were obtained for upregulated and downregulated DE-miRNAs, respectively. Subsequently, 1,715 upregulated DEGs and 1,259 downregulated DEGs were identified. Then, 149 and 295 potential downregulated and upregulated genes commonly appeared in target genes of DE-miRNAs and DEGs were selected for GO annotation and KEGG pathway enrichment analysis. The downregulated genes were significantly enriched in cGMP-PKG signaling pathway and calcium signaling pathway whereas the upregulated genes were enriched in pathways in cancer and PI3K-Akt signaling pathway. Construction and analysis of PPI network showed that STXBP1 and TP53 were recognized as hub genes with the highest connectivity degrees. Expression analytic result of the top 20 hub genes in GBM using GEPIA database was generally identical with previous differential expression analysis for TCGA data. EGFR, PPP3CB, and MYO5A expression was significantly associated with patients' OS.

Conclusions: In this study, we established a potential GBM-related miRNA-mRNA regulatory network, which explores a comprehensive understanding of the molecular mechanisms and provides key clues in seeking novel therapeutic targets for GBM. In the future, more experiments need to be performed to validate our current findings.

miR-15b-5p targeting amyloid precursor protein is involved in the anti-amyloid eflect of curcumin in swAPP695-HEK293 cells

Curcumin exerts a neuroprotective effect on Alzheimer's disease; however, it is not known whether microRNAs are involved in this protective effect. This study was conducted using swAPP695-HEK293 cells as an Alzheimer's disease cell model. swAPP695-HEK293 cells were treated with 0, 0.5, 1, 2, 5, and 10 μM curcumin for 24 hours. The changes in miR-15b-5p, miR-19a-3p, miR-195-5p, miR-101-3p, miR-216b-5p, miR-16-5p and miR-185-5p expression were assessed by real-time quantitative polymerase chain reaction. The mRNA and protein levels of amyloid precursor protein, amyloid-β40 and amyloid-β42 were evaluated by quantitative real-time polymerase chain reaction, western blot assays and enzyme-linked immunosorbent assays. swAPP695-HEK293 cells were transfected with miR-15b-5p mimic, or treated with 1 μM curcumin 24 hours before miR-15b-5p inhibitor transfection. The effects of curcumin on amyloid precursor protein, amyloid-β40 and amyloid-β42 levels were evaluated by western blot assays and enzyme-linked immunosorbent assay. Luciferase assays were used to analyze the interaction between miR-15b-5p and the 3'-untranslated region of amyloid precursor protein. The results show that amyloid precursor protein and amyloid-β expression were enhanced in swAPP695-HEK293 cells compared with HEK293 parental cells. Curcumin suppressed the expression of amyloid precursor protein and amyloid-β and up-regulated the expression of miR-15b-5p in swAPP695-HEK293 cells. In addition, we found a negative association of miR-15b-5p expression with amyloid precursor protein and amyloid-β levels in the curcumin-treated cells. Luciferase assays revealed that miR-15b-5p impaired the luciferase activity of the plasmid harboring the 3'-untranslated region of amyloid precursor protein. These findings indicate that curcumin down-regulates the expression of amyloid precursor protein and amyloid-β in swAPP695-HEK293 cells, which was partially mediated by miR-15b-5p via targeting of the 3'-untranslated region of amyloid precursor protein.

microRNA diagnostic panel for Alzheimer's disease and epigenetic trade-off between neurodegeneration and cancer

microRNAs (miRNAs) have been extensively studied as potential biomarkers for Alzheimer's disease (AD). Their profiles have been analyzed in blood, cerebrospinal fluid (CSF) and brain tissue. However, due to the high variability between the reported data, stemming from the lack of methodological standardization and the heterogeneity of AD, the most promising miRNA biomarker candidates have not been selected. Our literature review shows that out of 137 miRNAs found to be altered in AD blood, 36 have been replicated in at least one independent study, and out of 166 miRNAs reported as differential in AD CSF, 13 have been repeatedly found. Only 3 miRNAs have been consistently reported as altered in three analyzed specimens: blood, CSF and the brain (hsa-miR-146a, hsa-miR-125b, hsa-miR-135a). Nonetheless, all 36 repeatedly differential miRNAs in AD blood are promising as components of the diagnostic panel. Given their predicted functions, such miRNA panel may report multiple pathways contributing to AD pathology, enabling the design of personalized therapies. In addition, the analysis revealed that the miRNAs dysregulated in AD overlap highly with miRNAs implicated in cancer. However, the directions of the miRNA changes are usually opposite in cancer and AD, indicative of an epigenetic trade-off between the two diseases.

Comparative study of microRNA profiling in one Chinese Family with PSEN1 G378E mutation

MicroRNAs are not widely studied in familial Alzheimer's disease cases, whether the microRNA profilings in familial Alzheimer's disease patients are similar to the sporadic AD patients is not known. This study aims to investigate the differential expression of microRNAs (miRNAs) associated with early-onset familial Alzheimer's disease (EO-FAD) in a Chinese family. We performed the gene mutation analysis in a family clinically diagnosed of EO-FAD. Micro-arrays were used to profile the miRNAs in cerebrospinal fluid of 2 affected members, 2 unaffected carriers and 2 mutation negative controls. The clinical presentation confirmed the EO-FAD diagnosis, and a recurrent mutation of the PSEN1 p.G378E was found in the family. The result showed that in the miRNAs expression profile, a total of 166 miRNAs were up-regulated and 3 miRNAs were down-regulated in the affected individuals compared with mutation negative individuals. But after Benjamini Hochberg FDR correction, only 25 miRNAs were significantly up-regulated and no miRNA was down-regulated, the levels of miR-30a-5p, miR-4758-3p and let-7a-3p were elevated significantly. Compared with mutation negative controls, 21 miRNAs were up-regulated and 18 microRNAs were down-regulated in the unaffected mutation carriers, after Benjamini Hochberg FDR correction, miR-345-5p was up-regulated and miR-4795-3p was down-regulated in the unaffected mutation carriers. And there was no difference between the affected members and unaffected mutation carriers. GO database showed that the top biological processes affected by the predicted target genes are nucleic acid binding transcription factor activity and transcription factor activity (sequence-specific DNA binding) (GO:0001071 and GO:0003700). The result of KEGG pathways showed 64 pathways were implicated in the regulatory network. The present study identified the miRNA profiling of Chinese siblings with G378E mutation in the PSEN1. Compared with mutation negative controls, the levels of 25 miRNAs including miR-30a-5p, miR-4758-3p and let-7a-3p were elevated significantly in the affected members, miR-345-5p was up-regulated and miR-4795-3p was down-regulated in the unaffected mutation carriers. Our study showed the microRNA profilings in the cases of a EO-FAD family with PSEN1 p.G378E mutation, but because of the individuals in the family was small, the results in other types of EO-FAD still need further studied.

Reprogramming Cells for Synergistic Combination Therapy with Nanotherapeutics against Uveal Melanoma

Uveal melanoma (UM) is the most common primary intraocular malignant tumor in adults and around half of the patients develop metastasis and die shortly after because of the lack of effective therapies for metastatic UM. Consequently, new therapeutic approaches to this disease are welcome. In this regard, microRNAs have been shown to have a key role in neoplasia progression and have the potential to be used as therapeutic tools. In addition, in different cancers including UM, a particular microRNA signature appears that is different from healthy cells. Thus, restoring the regular levels of microRNAs could restore the normal behavior of cells. In this study, four microRNAs downregulated in UM have been chosen to reprogram cancer cells, to promote cell death or increase their sensitivity to the chemotherapeutic SN38. Furthermore, to improve the internalization, stability and/or solubility of the therapeutic molecules employed in this approach, gold nanoparticles (AuNPs) were used as carriers. Remarkably, this study found a synergistic effect when the four oligonucleotides were employed and when the chemotherapeutic drug was added.

Extraction of microRNAs from biological matrices with titanium dioxide nanofibers

MicroRNAs (miRNAs) are small RNAs that bind to mRNA targets and regulate their translation. A functional study of miRNAs and exploration of their utility as disease markers require miRNA extraction from biological samples, which contain large amounts of interfering compounds for downstream RNA identification and quantification. The most common extraction methods employ silica columns or the TRIzol reagent but give out low recovery for small RNAs probably due to their short strand lengths. Herein, we fabricated the titanium dioxide nanofibers using electrospinning to facilitate miRNA extraction and developed the optimal buffer conditions to improve miRNA recovery from biological matrices of cell lysate and serum. We found that our TiO₂ fibers could obtain a recovery of 18.0 ± 3.6% for miRNA fibers while carrying out the extraction in the more complex medium of cell lysate, much higher than the 0.02 ± 0.0001% recovery from the commercial kit. The much improved extraction of miRNAs from our fibers could be originated from the strong coordination between TiO₂ and RNA's phosphate backbone. In addition, the binding, washing, and elution buffers judiciously developed in the present study can achieve selective extraction of small RNA shorter than 500 nucleotides in length. Our results demonstrate that TiO₂ nanofibers can work as a valuable tool for extraction of miRNAs from biological samples with high recovery. Graphical abstract Schematic for extraction of small RNAs using TiO₂ nanofibers.

The Role of MicroRNAs in Aβ Deposition and Tau Phosphorylation in Alzheimer's Disease

Alzheimer’s disease (AD), with main clinical features of progressive impairment in cognitive and behavioral functions, is the most common degenerative disease of the central nervous system. Recent evidence showed that microRNAs (miRNAs) played important roles in the pathological progression of AD. In this article, we reviewed the promising role of miRNAs in both Aβ deposition and Tau phosphorylation, two key pathological characters in the pathological progression of AD, which might be helpful for the understanding of pathogenesis and the development of new strategies of clinical diagnosis and treatment of AD.

MicroRNAs in model and complex organisms

Non-coding RNAs such as microRNAs (miRNAs) are very tiny ribonucleotides having an essential role in gene regulation at both post-transcriptional and translational levels. They are very conserved and expressed in worms, flies, plants, and mammals in a sequence-specific manner. Furthermore, it is now possible to clone miRNAs using the new genome editing tool CRISPR/cas9, which shows benefit in control of untargeted effect. In this special issue, we tried to cover researches associated with functional roles of miRNAs accross model and complex organisms.

Synaptic Dysfunction in Alzheimer's Disease: Aβ, Tau, and Epigenetic Alterations

Alzheimer's disease (AD) is a complex neurodegenerative disorder characterized in the early stages by loss of learning and memory. However, the mechanism underlying these symptoms remains unclear. The best correlation between cognitive decline and pathological changes is in synaptic dysfunction. Histopathological hallmarks of AD are the abnormal aggregation of Aβ and Tau. Evidence suggests that Aβ and Tau oligomers contribute to synaptic loss in AD. Recently, direct links between epigenetic alterations, such as dysfunction in non-coding RNAs (ncRNAs), and synaptic pathologies have emerged, raising interest in exploring the potential roles of ncRNAs in the synaptic deficits in AD. In this paper, we summarize the potential roles of Aβ, Tau, and epigenetic alterations (especially by ncRNAs) in the synaptic dysfunction of AD and discuss the novel findings in this area.

Chronically dysregulated NOTCH1 interactome in the dentate gyrus after traumatic brain injury

Traumatic brain injury (TBI) can result in several dentate gyrus-regulated disabilities. Almost nothing is known about the chronic molecular changes after TBI, and their potential as treatment targets. We hypothesized that chronic transcriptional alterations after TBI are under microRNA (miRNA) control. Expression of miRNAs and their targets in the dentate gyrus was analyzed using microarrays at 3 months after experimental TBI. Of 305 miRNAs present on the miRNA-array, 12 were downregulated (p<0.05). In parallel, 75 of their target genes were upregulated (p<0.05). A bioinformatics analysis of miRNA targets highlighted the dysregulation of the transcription factor NOTCH1 and 39 of its target genes (NOTCH1 interactome). Validation assays confirmed downregulation of miR-139-5p, upregulation of Notch1 and its activated protein, and positive enrichment of NOTCH1 target gene expression. These findings demonstrate that miRNA-based transcriptional regulation can be present at chronic time points after TBI, and highlight the NOTCH1 interactome as one of the mechanisms behind the dentate gyrus pathology-related morbidities.

miRNases: Novel peptide-oligonucleotide bioconjugates that silence miR-21 in lymphosarcoma cells

MicroRNAs (miRNAs) are active regulators in malignant growth and constitute potential targets for anticancer therapy. Consequently, considerable effort has focused on identifying effective ways to modulate aberrant miRNA expression. Here we introduce and assess a novel type of chemically engineered biomaterial capable of cleaving specific miRNA sequences, i.e. miRNA-specific artificial ribonucleases (hereafter 'miRNase'). The miRNase template presented here consists of the catalytic peptide Acetyl-[(LeuArg)₂Gly]₂ covalently attached to a miRNA-targeting oligonucleotide, which can be linear or hairpin. The peptide C-terminus is conjugated to an aminohexyl linker located at either the 3'- or 5'-end of the oligonucleotide. The cleavage efficacy, structural aspects of cleavage and biological relevance of a set of these designed miRNases was assayed with respect to highly oncogenic miR-21. Several miRNases demonstrated effective site-selective cleavage of miR-21 exclusively at G-X bonds. One of the most efficient miRNase was shown to specifically inhibit miR-21 in lymphosarcoma cells and lead to a reduction in their proliferative activity. This report provides the first experimental evidence that metallo-independent peptide-oligonucleotide chemical ribonucleases are able to effectively and selectively down-regulate oncogenic miRNA in tumour cells, thus suggesting their potential in development of novel therapeutics aimed at overcoming overexpression of disease-related miRNAs.

An integrated proteomics approach shows synaptic plasticity changes in an APP/PS1 Alzheimer's mouse model

The aim of this study was to elucidate the molecular signature of Alzheimer's disease-associated amyloid pathology.We used the double APPswe/PS1ΔE9 mouse, a widely used model of cerebral amyloidosis, to compare changes in proteome, including global phosphorylation and sialylated N-linked glycosylation patterns, pathway-focused transcriptome and neurological disease-associated miRNAome with age-matched controls in neocortex, hippocampus, olfactory bulb and brainstem. We report that signalling pathways related to synaptic functions associated with dendritic spine morphology, neurite outgrowth, long-term potentiation, CREB signalling and cytoskeletal dynamics were altered in 12 month old APPswe/PS1ΔE9 mice, particularly in the neocortex and olfactory bulb. This was associated with cerebral amyloidosis as well as formation of argyrophilic tangle-like structures and microglial clustering in all brain regions, except for brainstem. These responses may be epigenetically modulated by the interaction with a number of miRNAs regulating spine restructuring, Aβ expression and neuroinflammation.We suggest that these changes could be associated with development of cognitive dysfunction in early disease states in patients with Alzheimer's disease.

The role of microRNAs in gallbladder cancer

MicroRNAs (also referred to as miRNAs or miRs) play a crucial role in post-transcriptional gene regulation and serve as negative gene regulators by controlling a variety of target genes and regulating diverse biological processes, such as cell proliferation, invasion, migration and apoptosis. Aberrant expression of miRNAs is associated with the development and progression of cancer. Recent studies have reported that miRNAs may repress or promote the expression of cancer-related genes via several different signaling pathways in gallbladder cancer (GBC) patients and may function as tumor suppressors or oncogenes, thus providing a promising tool for the diagnosis and therapeutics of GBCs. In this review, we summarize the role of dysregulawted miRNA expression in the signaling pathways implicated in GBC and discuss the significant role of circulating miRNAs in GBC. Therefore, miRNAs may serve as novel therapeutic targets as well as diagnostic or prognostic markers in GBC.

MicroRNA (miRNA)-Mediated Pathogenetic Signaling in Alzheimer's Disease (AD)

Alzheimer's disease (AD) is an expanding health and socioeconomic concern in industrialized societies, and the leading cause of intellectual impairment in our aging population. The cause of AD remains unknown, and there are currently no effective treatments to stop or reverse the progression of this uniquely human and age-related neurological disorder. Elucidation of the AD mechanism and factors that contribute to the initiation, progression, and spreading of this chronic and fatal neurodegeneration will ultimately result in improved and effective diagnostics and therapeutic strategies.microRNAs (miRNAs) comprise a relatively recently discovered category of 20-24 nucleotide non-coding RNAs that function post-transcriptionally in shaping the transcriptome of the cell, and in doing so, contribute to the molecular-genetics and phenotype of human CNS health and disease. To date about 2550 unique mature human miRNAs have been characterized, however only highly selected miRNA populations appear to be enriched in different anatomical compartments within the CNS.This general commentary for the 'Special Issue: 40th Year of Neurochemical Research' will bring into perspective (i) some very recent findings on the extraordinary biophysics and signaling properties of CNS miRNA in AD and aging human brain; (ii) how specific intrinsic biophysical attributes of miRNAs may play defining roles in the establishment, proliferation and spreading of the AD phenotype; and (iii) how miRNAs can serve as prospective therapeutic targets and biomarkers potentially useful in the clinical management of this terminal neurological disease whose incidence in our rapidly aging population is reaching epidemic proportions.

Increased number of circulating exosomes and their microRNA cargos are potential novel biomarkers in alcoholic hepatitis

Background

It has been well documented that alcohol and its metabolites induce injury and inflammation in the liver. However, there is no potential biomarker to monitor the extent of liver injury in alcoholic hepatitis patients. MicroRNAs (miRNAs) are a class of non-coding RNAs that are involved in various physiologic and pathologic processes. In the circulation, a great proportion of miRNAs is associated with extracellular vesicles (EVs)/exosomes. Here, we hypothesized that the exosome-associated miRNAs can be used as potential biomarkers in alcoholic hepatitis (AH).

Methods

Exosomes were isolated from sera of alcohol-fed mice or pair-fed mice, and plasma of alcoholic hepatitis patients or healthy controls by ExoQuick. The exosomes were characterized by transmission electron microscopy and Western blot and enumerated with a Nanoparticle Tracking Analysis system. Firefly™ microRNA Assay was performed on miRNA extracted from mice sera. TaqMan microRNA assay was used to identify differentially expressed miRNAs in plasma of cohort of patients with AH versus controls followed by construction of receiver operating characteristic (ROC) curves to determine the sensitivity and specificity of the candidates.

Results

The total number of circulating EVs was significantly increased in mice after alcohol feeding. Those EVs mainly consisted of exosomes, the smaller size vesicle subpopulation of EVs. By performing microarray screening on exosomes, we found nine inflammatory miRNAs which were deregulated in sera of chronic alcohol-fed mice compared to controls including upregulated miRNAs: miRNA-192, miRNA-122, miRNA-30a, miRNA-744, miRNA-1246, miRNA 30b and miRNA-130a. The ROC analyses indicated excellent diagnostic value of miRNA-192, miRNA-122, and miRNA-30a to identify alcohol-induced liver injury. We further validated findings from our animal model in human samples. Consistent with the animal model, total number of EVs, mostly exosomes, was significantly increased in human subjects with AH. Both miRNA-192 and miRNA-30a were significantly increased in the circulation of subjects with AH. miRNA-192 showed promising value for the diagnosis of AH.

Conclusion

Elevated level of EVs/exosomes and exosome-associated miRNA signature could serve as potential diagnostic markers for AH. In addition to the biomarker diagnostic capabilities, these findings may facilitate development of novel strategies for diagnostics, monitoring, and therapeutics of AH.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0623-9) contains supplementary material, which is available to authorized users.