MicroRNA: Implications for Alzheimer Disease and other Human CNS Disorders

Potential therapeutic natural compounds for the treatment of Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a complicated neurodegenerative disease with cognitive impairment occurring in the older people, in which extracellular accumulation of β-amyloid and intracellular aggregation of hyperphosphorylated tau are regarded as the prevailing theories. However, the exact AD mechanism has not been determined. Moreover, there is no effective treatment available in phase III trials to eradicate AD, which is imperative to explore novel treatments.

PURPOSE

A number of up-to-date pre-clinical studies on cognitive impairment is beneficial to clarify the pathology of AD. This review recapitulates several advances in AD pathobiology and discusses the neuroprotective effects of natural compounds, such as phenolic compounds, natural polysaccharides and oligosaccharides, peptide, and lipids, underscoring the therapeutic potential for AD.

METHODS

Electronic databases involving PubMed, Web of Science, and Google Scholar were searched up to October 2023. Articles were conducted using the keywords like Alzheimer's disease, pathogenic mechanisms, natural compounds, and neuroprotection.

RESULT

This review summarized several AD pathologies and the neuroprotective effects of natural compounds such as natural polysaccharides and oligosaccharides, peptide, and lipids.

CONCLUSION

We have discussed the pathogenic mechanisms of AD and the effect natural products on neurodegenerative diseases particularly in treating AD. Specifically, we investigated the molecular pathways and links between natural compounds and Alzheimer's disease such as through NF-κB, Nrf2, and mTOR pathway. Further investigation is necessary in exploring the bioactivity and effectiveness of natural compounds in clinical trials, which may provide a promising treatment for AD patients.

Non-coding RNAs in disease: from mechanisms to therapeutics

Non-coding RNAs (ncRNAs) are a heterogeneous group of transcripts that, by definition, are not translated into proteins. Since their discovery, ncRNAs have emerged as important regulators of multiple biological functions across a range of cell types and tissues, and their dysregulation has been implicated in disease. Notably, much research has focused on the link between microRNAs (miRNAs) and human cancers, although other ncRNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), are also emerging as relevant contributors to human disease. In this Review, we summarize our current understanding of the roles of miRNAs, lncRNAs and circRNAs in cancer and other major human diseases, notably cardiovascular, neurological and infectious diseases. Further, we discuss the potential use of ncRNAs as biomarkers of disease and as therapeutic targets.

Augmentation of 2-arachidonoylglycerol signaling in astrocytes maintains synaptic functionality by regulation of miRNA-30b

2-Arachidonoylglycerol (2-AG), the most abundant endocannabinoid, displays anti-inflammatory and neuroprotective properties. Inhibition of 2-AG degradation by inactivation of monoacylglycerol lipase (MAGL), a key enzyme degrading 2-AG in the brain, alleviates neuropathology and improves synaptic and cognitive functions in animal models of neurodegenerative diseases. In particular, global inactivation of MAGL by genetic deletion of mgll enhances hippocampal long-term potentiation (LTP) and hippocampus-dependent learning and memory. However, our understanding of the molecular mechanisms by which chronic inactivation of MAGL enhances synaptic activity is still limited. Here, we provide evidence that pharmacological inactivation of MAGL suppresses hippocampal expression of miR-30b, a small non-coding microRNA, and upregulates expression of its targets, including ephrin type-B receptor 2 (ephB2), sirtuin1 (sirt1), and glutamate ionotropic receptor AMPA type subunit 2 (GluA2). Importantly, suppression of miR-30b and increase of its targets by inactivation of MAGL result primarily from inhibition of 2-AG metabolism in astrocytes, rather than in neurons. Inactivation of MAGL in astrocytes prevents miR-30b overexpression-induced impairments in synaptic transmission and long-term potentiation (LTP) in the hippocampus. Suppression of miR-30b expression by inactivation of MAGL is apparently associated with augmentation of 2-AG signaling, as 2-AG induces a dose-dependent decrease in expression of miR-30b. 2-AG- or MAGL inactivation-suppressed expression of miR-30b is not mediated via CB1R, but by peroxisome proliferator-activated receptor γ (PPARγ). This is further supported by the results showing that MAGL inactivation-induced downregulation of miR-30b and upregulation of its targets are attenuated by antagonism of PPARγ, but mimicked by PPARγ agonists. In addition, we observed that 2-AG-induced reduction of miR-30b expression is mediated via NF-kB signaling. Our study provides evidence that 2-AG signaling in astrocytes plays an important role in maintaining the functional integrity of synapses in the hippocampus by regulation of miR-30b expression.

Multiomics and artificial intelligence enabled peripheral blood-based prediction of amnestic mild cognitive impairment

BACKGROUND

Since dementia is preventable with early interventions, biomarkers that assist in diagnosing early stages of dementia, such as mild cognitive impairment (MCI), are urgently needed.

METHODS

Multiomics analysis of amnestic MCI (aMCI) peripheral blood (n = 25) was performed covering the transcriptome, microRNA, proteome, and metabolome. Validation analysis for microRNAs was conducted in an independent cohort (n = 12). Artificial intelligence was used to identify the most important features for predicting aMCI.

FINDINGS

We found that hsa-miR-4455 is the best biomarker in all omics analyses. The diagnostic index taking a ratio of hsa-miR-4455 to hsa-let-7b-3p predicted aMCI patients against healthy subjects with 97% overall accuracy. An integrated review of multiomics data suggested that a subset of T cells and the GCN (general control nonderepressible) pathway are associated with aMCI.

INTERPRETATION

The multiomics approach has enabled aMCI biomarkers with high specificity and illuminated the accompanying changes in peripheral blood. Future large-scale studies are necessary to validate candidate biomarkers for clinical use.

Establishment of preanalytical conditions for microRNA profile analysis of clinical plasma samples

The relationship between the expression of microRNAs (miRNAs) in blood and a variety of diseases has been investigated. MiRNA-based liquid biopsy has attracted much attention, and cancer-specific miRNAs have been reported. However, the results of analyses of the expression of these miRNAs vary among studies. The reproduction of results regarding miRNA expression levels could be difficult if there are differences in the data acquisition process. Previous studies have shown that the anticoagulant type used during plasma preparation and sample storage conditions could contribute to differences in measured miRNA levels. Thus, the impact of these preanalytical conditions on comprehensive miRNA expression profiles was examined. First, the miRNA expression profiles of samples obtained from healthy volunteers were analyzed using next-generation sequencing. Based on an analysis of the library concentration, human genome identification rate, ratio of unique sequences and expression profiles, the optimal preanalytical conditions for obtaining highly reproducible miRNA expression profiles were established. The optimal preanalytical conditions were as follows: ethylenediaminetetraacetic acid (EDTA) as the anticoagulant, whole-blood storage at room temperature within 6 hours, and plasma storage at 4°C or -20°C within 30 days. Next, plasma samples were collected from 60 cancer patients (3 facilities × 20 patients/facility), and miRNA expression profiles were analyzed. There were no significant differences in measurements except in the expression of erythrocyte-derived hsa-miR-451a. However, the variation in hsa-miR-451a levels was smaller among facilities than among individuals. This finding suggests that samples obtained from the same facility could show significantly different degrees of hemolysis across individuals. We found that the standardization of anticoagulant use and storage conditions contributed to reducing the variation in sample quality across facilities. The findings from this study could be useful in developing protocols for collecting samples from multiple facilities for cancer screening tests.

Plasma microRNAs as potential biomarkers in early Alzheimer disease expression

The microRNAs (miRNAs) are potential biomarkers for complex pathologies due to their involvement in the regulation of several pathways. Alzheimer Disease (AD) requires new biomarkers in minimally invasive samples that allow an early diagnosis. The aim of this work is to study miRNAS as potential AD biomarkers and their role in the pathology development. In this study, participants (n = 46) were classified into mild cognitive impairment due to AD (MCI-AD, n = 19), preclinical AD (n = 8) and healthy elderly controls (n = 19), according to CSF biomarkers levels (amyloid β42, total tau, phosphorylated tau) and neuropsychological assessment. Then, plasma miRNAomic expression profiles were analysed by Next Generation Sequencing. Finally, the selected miRNAs were validated by quantitative PCR (q-PCR). A panel of 11 miRNAs was selected from omics expression analysis, and 8 of them were validated by q-PCR. Individually, they did not show statistically significant differences among participant groups. However, a multivariate model including these 8 miRNAs revealed a potential association with AD for three of them. Specifically, relatively lower expression levels of miR-92a-3p and miR-486-5p are observed in AD patients, and relatively higher levels of miR-29a-3p are observed in AD patients. These biomarkers could be involved in the regulation of pathways such as synaptic transmission, structural functions, cell signalling and metabolism or transcription regulation. Some plasma miRNAs (miRNA-92a-3p, miRNA-486-5p, miRNA-29a-3p) are slightly dysregulated in AD, being potential biomarkers of the pathology. However, more studies with a large sample size should be carried out to verify these results, as well as to further investigate the mechanisms of action of these miRNAs.

MicroRNA expression profiles of peripheral blood and mononuclear cells in myasthenia gravis: A systematic review

BACKGROUND

Studies have described the role of microRNAs (miRNAs) in thymic function, along with directly observing the altered expression of miRNAs in thymuses of myasthenia gravis (MG) patients; so, miRNAs became a core component in the pathophysiology of MG. However, because the miRNA analysis results are contradictory, the identification of MG-related miRNAs is daunting.

OBJECTIVE

We did a systematic review of studies analyzing the miRNA expression profile of peripheral blood and mononuclear cells for patients with MG.

METHODS

We ran a database search in PubMed, Scopus, and Web of Science on August 17, 2021. Original articles that analyzed miRNA profiles in peripheral blood (serum, plasma, and whole blood) and peripheral blood mononuclear cells (PBMCs) for patients with MG in comparison with a non-MG or healthy control (HC) group were eligible. The quality of studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2).

RESULTS

26 studies were included. The quality of studies was fair (median score, 5). Among 226 different miRNAs that were deregulated in at least one study (range, 1-87), ten miRNAs were significantly deregulated in three or more studies. Five miRNAs (50%) showed the same deregulation: miR-106b-3p and miR-21-5p were consistently upregulated, and miR-20b, miR-15b, and miR-16 were consistently downregulated. Also, there were five miRNAs that were mostly upregulated, miR-150-5p, miR-146a, miR-30e-5p, and miR-338-3p, or downregulated, miR-324-3p, across studies.

CONCLUSION

These miRNAs contribute to different pathways, importantly neural apoptosis and autophagy, inflammation, T regulatory cell development, and T helper cell balance. Prior to being used for diagnostic and therapeutic purposes, it is required to pursue molecular mechanisms these consistently and mostly dysregulated miRNAs specifically use in the context of MG.

miR‑382‑3p downregulation contributes to the carcinogenesis of lung adenocarcinoma by promoting AKT SUMOylation and phosphorylation

Lung adenocarcinoma (LA), the primary histological type of non-small cell lung cancer, is still incurable; its diagnosis and treatment remain a major clinical challenge. A previous study by our group examined the microRNA (miRNA/miR) expression profile in the extracellular vesicles from patients with LA and healthy controls and indicated that miR-382-3p levels were reduced in patients with LA. However, the precise roles of miR-382-3p in LA have so far remained elusive. In the present study, the miR-382-3p levels in tumor and adjacent non-tumor control samples from 78 patients with LA were examined and it was identified that miR-382-3p expression was reduced in LA tumor samples compared with that in adjacent non-tumor control tissues (P=0.022). Furthermore, miR-382-3p overexpression inhibited LA growth in a xenograft mouse model. Prediction results indicated that miR-382-3p may regulate protein ubiquitination and SUMOylation. Small ubiquitin-like modifier (SUMO)1 activating enzyme subunit 1 (SAE1), one of the key components of the SUMO-activating complex, was identified as a direct target of miR-382-3p via dual-luciferase and immunoblotting assays. In patients with LA, miR-382-3p expression was negatively correlated with SAE1 protein levels (r=-0.39, P<0.05) and higher SAE1 expression contributed to poor prognosis (P<0.01). Using immunoprecipitation, it was identified that miR-382-3p reduction-induced SAE1 overexpression upregulated AKT SUMOylation, which further promoted AKT phosphorylation and activated the AKT signaling pathway. miR-382-3p inhibition promoted proliferation and inhibited apoptosis in LA cell lines, which was restored by SAE1 knockdown. In conclusion, the present study revealed that downregulation of miR-382-3p contributed to the carcinogenesis of LA via upregulation of SAE1 and promotion of AKT SUMOylation, providing a candidate target for LA treatment.

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.

Fine-tuning miR-21 expression and inhibition of EMT in breast cancer cells using aromatic-neomycin derivatives

MicroRNAs (miRs) are a class of endogenously expressed non-coding RNAs that negatively regulate gene expression within cells and participate in maintaining cellular homeostasis. By targeting 3' UTRs of target genes, individual miRs can control a wide array of gene expressions. Previous research has shed light upon the fact that aberrantly expressed miRs within cells can pertain to diseased conditions, such as cancer. Malignancies caused due to miRs are because of the high expression of onco-miRs or feeble expression of tumor-suppressing miRs. Studies have also shown miRs to engage in epithelial to mesenchymal transition (EMT), which allows cancer cells to become more invasive and metastasize. miR-21 is an onco-miR highly expressed in breast cancer cells and targets protein PTEN, which abrogates EMT. Therefore, we discuss an approach where in-house-developed peptidic amino sugar molecules have been used to target pre-miR-21 to inhibit miR-21 biogenesis, and hence antagonize its tumor-causing effect and inhibit EMT. Our study shows that small-molecule-based fine-tuning of miR expression can cause genotypic as well as phenotypic changes and also reinstates the potential and importance of nucleic acid therapeutics.

Relationship between mir-126 expression in children with psoriasis, disease progression and therapeutic response

This study aimed to investigate the expression level of miR-126 in children with psoriasis in the epidermis affected by psoriasis and intact buccal epithelium, establish the impact on the characteristics of the course of psoriasis and the results of therapy in children with psoriasis of initial expression levels of miR-126. miR-126 expression levels in psoriatic keratinocytes and buccal epithelium were determined in 54 children with psoriasis on the severity of psoriasis, treatment efficacy. miR-126 levels in the buccal epithelium in children with psoriasis were reduced compared to healthy children (AUC=0.776±0.048, p<0.001). There were no discrepancies between miR-126 expression levels in psoriatic keratinocytes and buccal epithelium (p=0.097). There are statistically significant discrepancies between miR-126 expression levels in the psoriatic epidermis depending on the clinical form of psoriasis (AUC=0.637±0.056; p=0.014) and severity according to BSA (AUC=0.634±0.063; p=0.034). Depending on the miR-126 level in the buccal epithelium, the response to treatment (PASI<75) in children with high miR-126 is worse than in children with expected miR-126 levels (OR 2.79; 95%; CI: 1.19 - 6.51). Treatment failures were observed in children with high levels of miR-126 in the buccal epithelium compared to miR-126 in the psoriatic epidermis: children aged 12/13 to 17 years (OR 2.44; 95% CI: 1.02 - 5.85), children with PGA=4 (OR 3.16; 95% CI: 1.34 - 7.43). The location and level of miR-126 expression affects the course of psoriasis and the outcome of treatment. High levels of miR-126 in psoriatic keratinocytes lead to manifestations of plaque psoriasis with a course of moderate to severe forms. Initial miR-126 levels in the buccal epithelium in children with psoriasis are a prognostic criterion for response to therapy and can be used as a marker for prescribing systemic treatment.

PAR-CLIP: A Method for Transcriptome-Wide Identification of RNA Binding Protein Interaction Sites

During post-transcriptional gene regulation (PTGR), RNA binding proteins (RBPs) interact with all classes of RNA to control RNA maturation, stability, transport, and translation. Here, we describe Photoactivatable-Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation (PAR-CLIP), a transcriptome-scale method for identifying RBP binding sites on target RNAs with nucleotide-level resolution. This method is readily applicable to any protein directly contacting RNA, including RBPs that are predicted to bind in a sequence- or structure-dependent manner at discrete RNA recognition elements (RREs), and those that are thought to bind transiently, such as RNA polymerases or helicases.

Elevated Expression of MiR-17 in Microglia of Alzheimer's Disease Patients Abrogates Autophagy-Mediated Amyloid-β Degradation

Autophagy is a proposed route of amyloid-β (Aβ) clearance by microglia that is halted in Alzheimer’s Disease (AD), though mechanisms underlying this dysfunction remain elusive. Here, primary microglia from adult AD (5xFAD) mice were utilized to demonstrate that 5xFAD microglia fail to degrade Aβ and express low levels of autophagy cargo receptor NBR1. In 5xFAD mouse brains, we show for the first time that AD microglia express elevated levels of microRNA cluster Mirc1/Mir17-92a, which is known to downregulate autophagy proteins. By in situ hybridization in post-mortem AD human tissue sections, we observed that the Mirc1/Mir17-92a cluster member miR-17 is also elevated in human AD microglia, specifically in the vicinity of Aβ deposits, compared to non-disease controls. We show that NBR1 expression is negatively correlated with expression of miR-17 in human AD microglia via immunohistopathologic staining in human AD brain tissue sections. We demonstrate in healthy microglia that autophagy cargo receptor NBR1 is required for Aβ degradation. Inhibiting elevated miR-17 in 5xFAD mouse microglia improves Aβ degradation, autophagy, and NBR1 puncta formation in vitro and improves NBR1 expression in vivo. These findings offer a mechanism behind dysfunctional autophagy in AD microglia which may be useful for therapeutic interventions aiming to improve autophagy function in AD.

Estradiol exerts a neuroprotective effect on SH-SY5Y cells through the miR-106b-5p/TXNIP axis

Alzheimer's disease (AD) is a neurodegenerative disease. Thioredoxin and thioredoxin-interacting protein (TXNIP) complexes help sustain cell oxidation/reduction balance. In the present study, we verified the neuroprotective role of estradiol against amyloid-beta 42 in SH-SY5Y cells through inhibiting TXNIP expression, promoting cell viability and DNA synthesis ability, inhibiting cell apoptosis, and affecting caspase and Bax/Bcl-2 apoptotic signaling. miR-106b-5p could bind to TXNIP 3'-untranslated region to inhibit the expression level of TXNIP. Within SH-SY5Y cells, miR-106b-5p inhibition repressed cell viability and DNA synthesis ability and promoted cell apoptosis through caspase and Bax/Bcl-2 apoptotic signaling, while miR-106b-5p overexpression or TXNIP knockdown exerted the opposite effects on SH-SY5Y cells; TXNIP knockdown remarkably attenuated the roles of miR-106b-5p inhibition. In conclusion, estradiol treatment on SH-SY5Y cells downregulates TXNIP expression and upregulates miR-106b-5p expression. miR-106b-5p exerts a neuroprotective effect on SH-SY5Y cells by promoting cell proliferation and inhibiting cell apoptosis through targeting TXNIP.

MicroRNA-451 Aggravates Kainic Acid-induced Seizure and Neuronal Apoptosis by Targeting GDNF

AIM

Epilepsy is a common and serious neurological disease that causes recurrent episodes, but its molecular mechanism remains unclear. Abnormal miRNA expression is associated with epilepsy, including miR-451. This research investigated the role of miR-451 in seizure and its detailed mechanism.

METHODS

The seizure mice model was induced by kainic acid (KA) injection to the right lateral cerebral ventricle. Behavioral changes in mice were observed and evaluated by the Racine Scale. The miR-451 knockout mice were established by adenovirus infection. The in vitro model was performed by miR-451 mimics transfected HEK-293 cells. The amount of neuronal death and morphological changes were evaluated by Nissl staining and H&E staining.

RESULTS

The results showed that miR-451 is up regulated in KA-induced seizure models and miR- 451 knockout decreased the behavior score and improved the pathological changes of the hippocampus. Besides, MiR-451 knockout inhibited the apoptosis of hippocampal neurons. Bioinformatics studies have shown that glial cell line-derived neurotrophic factor (GDNF) is a target gene of miR-451. MiR-451 could negatively regulate the expression of GDNF. GDNF overexpression could reverse the effect of miR-451 on KA induced brain injury and neuronal apoptosis.

CONCLUSION

This research demonstrates that miR-451 can affect the behavior of KA-induced epilepsy mice and hippocampal neuronal damage by regulating GDNF expression. The results would provide an experimental foundation for further research about the potential contribution of mi- RNAs to epilepsy pathophysiology.

Lower growth arrest-specific 5 level in endometrium is related to endometriosis via promoting cell proliferation and angiogenesis

Long noncoding RNAs are a group of more than 200 nt, nonprotein coding RNAs, some of which are dysregulated in many pathophysiological processes including endometriosis. This study aims to clarify the roles of dysregulated growth arrest-specific 5 (GAS5) in patients with endometriosis, and unveil the underlying mechanisms. We obtained endometrium samples from 37 patients with endometriosis and 23 controls without endometriosis. Primary endometrial stromal cells (ESCs) and endothelial cells were separated from the endometrium. Levels of GAS5 were quantified using quantitative real-time polymerase chain reaction, and levels of p27, cleaved caspase-3, cleaved poly (ADP-Ribose) polymerase 1, vascular endothelial growth factor A, tissue inhibitor of metalloproteinases 3 (TIMP3), and trypsin-modified soy protein 10 were assessed by immunoblotting. Cell viability was examined using MTT assays, and the cell cycle and apoptosis were analyzed by flow cytometry. Endothelial cell tube formation capacity was assayed in vitro. GAS5 and p27 levels were found lower in the endometrium samples from patients with endometriosis. Primary ESCs from patients with endometriosis had increased viability, reduced apoptosis, and a relatively uncontrolled cell cycle. Gain- and loss-of-function studies confirmed that GAS5 regulated p27 expression in ESCs. Furthermore, GAS5 level was relatively low in primary endothelial cells from patients with endometriosis and GAS5 acted as an angiogenesis inhibitor by regulating the miR-181c-TIMP3 axis. Thus, lower GAS5 level in endometrium might be related to endometriosis by regulating cell proliferation, apoptosis, cell cycle, and angiogenesis.

RP11-874J12.4, a novel lncRNA, confers chemoresistance in human gastric cancer cells by sponging miR-3972 and upregulating SSR2 expression

Increasing evidence has revealed the contributions of long noncoding RNAs (lncRNAs) in the modulation of drug resistance in gastric cancer. In the present study, we explored the role of a novel lncRNA, RP11-874J12.4, in regulating chemoresistance in gastric cancer and determined the underlying molecular mechanisms. We observed that compared with normal controls, human gastric cancer tissues and cell lines, including MKN-45 and AGS cells, expressed higher RP11-874J12.4 levels. RP11-874J12.4 knockdown sensitized MKN-45 and AGS cells to docetaxel and cisplatin in terms of cell viability and apoptosis rate. In addition, RP11-874J12.4 was found to be a competing endogenous RNA that sponged microRNA (miR)-3972, which showed significantly reduced expression in human gastric cancer tissues and cell lines. Furthermore, signal sequence receptor subunit 2 (SSR2) was identified as a downstream target of miR-3972, and the miR-3972/SSR2 axis was found to regulate chemoresistance in MKN-45 and AGS cells. SSR2 downregulation further sensitized gastric cancer cells with RP11-874J12.4 knockdown to chemotherapeutic drugs via enhanced apoptosis, which was evidenced by significantly upregulated expressions of cleaved caspase-3, cleaved caspase-9, and Bax and downregulated expression of Bcl-2. Furthermore, RP11-874J12.4 knockdown markedly inhibited the growth of xenograft MKN-45 cells in nude mice, which was associated with an increased expression of miR-3972 and decreased expression of SSR2 in tumors. Therefore, the RP11-874J12.4/miR-3972/SSR2 axis plays important roles in the regulation of chemoresistance in MKN-45 and AGS cells and may serve as a target for the diagnosis and treatment of human gastric cancer.

Abnormal expression of miR-135a in patients with depression and its possible involvement in the pathogenesis of the condition

At present, due to the increasing pressures on society and the stress of everyday living, the number of individuals suffering from depression has increased. Therefore, the treatment of depression has also received increasing attention. MicroRNA (miRNA/miR)-135a is a well-studied miRNA. It has been reported that miR-135a is significantly downregulated in patients with depression and may be a potential marker for the diagnosis of the condition. However, the specific mechanisms of action of miR-135a in patients with depression remain unclear. In the present study, it was found that miR-135a was downregulated in patients with depression, and in a mouse model of depression. The effects of miR-135a on depression-related symptoms in mice were then explored. In the mice with chronic unpredictable mild stress (CUMS) that were treated with miR-135a for 3 weeks, a significantly reduced level of weight gain was observed in comparison with the control group. In addition, treatment with miR-135a mimic significantly increased sucrose preference in the sucrose preference test in the mice, and reduced the immobility time in the forced swimming test and tail suspension test. Treatment with miR-135a mimic also inhibited CUMS-induced hippocampal cell apoptosis. Furthermore, treatment with miR-135a mimic and fluoxetine significantly reduced the CUMS-induced increase in the expression levels of inflammatory factors (IL-1β, IL-6 and TNF-α) in the hippocampus of the mice. Subsequently, reverse transcription-quantitative polymerase chain reaction and western blot analysis revealed that treatment with miR-135a mimic significantly inhibited the expression of Toll-like receptor 4 in the mouse hippocampus. In conclusion, the findings of the present study indicate that miR-135a may be a novel potential target for the treatment of depression.

A critical review of the epidemiological evidence of effects of air pollution on dementia, cognitive function and cognitive decline in adult population

Dementia is arguably the most pressing public health challenge of our age. Since dementia does not have a cure, identifying risk factors that can be controlled has become paramount to reduce the personal, societal and economic burden of dementia. The relationship between exposure to air pollution and effects on cognitive function, cognitive decline and dementia has stimulated increasing scientific interest in the past few years. This review of the literature critically examines the available epidemiological evidence of associations between exposure to ambient air pollutants, cognitive performance, acceleration of cognitive decline, risk of developing dementia, neuroimaging and neurological biomarker studies, following Bradford Hill guidelines for causality. The evidence reviewed has been consistent in reporting associations between chronic exposure to air pollution and reduced global cognition, as well as impairment in specific cognitive domains including visuo-spatial abilities. Cognitive decline and dementia incidence have also been consistently associated with exposure to air pollution. The neuro-imaging studies reviewed report associations between exposure to air pollution and white matter volume reduction. Other reported effects include reduction in gray matter, larger ventricular volume, and smaller corpus callosum. Findings relating to ischemic (white matter hyperintensities/silent cerebral infarcts) and hemorrhagic (cerebral microbleeds) markers of cerebral small vessel disease have been heterogeneous, as have observations on hippocampal volume and air pollution. The few studies available on neuro-inflammation tend to report associations with exposure to air pollution. Several effect modifiers have been suggested in the literature, but more replication studies are required. Traditional confounding factors have been controlled or adjusted for in most of the reviewed studies. Additional confounding factors have also been considered, but the inclusion of these has varied among the different studies. Despite all the efforts to adjust for confounding factors, residual confounding cannot be completely ruled out, especially since the factors affecting cognition and dementia are not yet fully understood. The available evidence meets many of the Bradford Hill guidelines for causality. The reported associations between a range of air pollutants and effects on cognitive function in older people, including the acceleration of cognitive decline and the induction of dementia, are likely to be causal in nature. However, the diversity of study designs, air pollutants and endpoints examined precludes the attribution of these adverse effects to a single class of pollutant and makes meta-analysis inappropriate.

Effects of therapeutic probiotics on modulation of microRNAs

Probiotics are beneficial bacteria that exist within the human gut, and which are also present in different food products and supplements. They have been investigated for some decades, due to their potential beneficial impact on human health. Probiotics compete with pathogenic microorganisms for adhesion sites within the gut, to antagonize them or to regulate the host immune response resulting in preventive and therapeutic effects. Therefore, dysbiosis, defined as an impairment in the gut microbiota, could play a role in various pathological conditions, such as lactose intolerance, gastrointestinal and urogenital infections, various cancers, cystic fibrosis, allergies, inflammatory bowel disease, and can also be caused by antibiotic side effects. MicroRNAs (miRNAs) are short non-coding RNAs that can regulate gene expression in a post-transcriptional manner. miRNAs are biochemical biomarkers that play an important role in almost all cellular signaling pathways in many healthy and disease states. For the first time, the present review summarizes current evidence suggesting that the beneficial properties of probiotics could be explained based on the pivotal role of miRNAs.

MicroRNA-542-3p Regulates P-glycoprotein Expression in Rat Epilepsy via the Toll-like Receptor 4/Nuclear Factor-kappaB Signaling Pathway

BACKGROUND

The function of microRNA-542-3p (miR-542-3p) in rat epilepsy is still unclear.

METHODS

The levels of miR-542-3p and toll-like receptor 4 (TLR4) were determined through quantitative real-time PCR. The protein levels were examined via the western blot analysis. The relationship between miR-542-3p and TLR4 was confirmed through luciferase assay. Pathological changes were analyzed via Hematoxylin-eosin (HE) and Nissl staining.

RESULTS

The rats and hippocampal cells were treated with kainic acid (KA) in vivo and in vitro. miR-542-3p was low in KA-treated rats, hippocampal cells and cerebrospinal fluid of patients with epilepsy. Further functional analysis showed that miR-542-3p overexpression inhibited KAinduced average seizure frequency, damage of hippocampal neuron and cell apoptosis, leading to the alleviation of the brain injury in epilepsy rats. miR-542-3p was determined to downregulate TLR4 expression. The relationship between miR-542-3p and TLR4 was confirmed. TLR4 knockdown reduced KA-induced nuclear factor-kappa B p65 (NF-κB p65), multidrug resistance 1 (MDR1), P-glycoprotein (P-gp) and apoptosis-associated protein levels. Further, for NF-κB p65, MDR1, P-gp and apoptosis-associated protein levels detection, miR-542-3p mimic showed a suppressive effect on these KA-induced protein levels, whereas TLR4 overexpression ameliorated the miR-542-3p-induced these protein levels in KA-treated epilepsy rats.

CONCLUSION

We identified that miR-542-3p attenuated seizure-induced brain injury and the expression of P-gp in epilepsy rats through inhibiting TLR4/NF-κB signaling pathway, which might contribute to improved epilepsy therapy.

Exosomal miRNAs as Potential Diagnostic Biomarkers in Alzheimer's Disease

Alzheimer’s disease (AD), a neurodegenerative disease, is linked to a variety of internal and external factors present from the early stages of the disease. There are several risk factors related to the pathogenesis of AD, among these exosomes and microRNAs (miRNAs) are of particular importance. Exosomes are nanocarriers released from many different cell types, including neuronal cells. Through the transfer of bioactive molecules, they play an important role both in the maintenance of physiological and in pathological conditions. Exosomes could be carriers of potential biomarkers useful for the assessment of disease progression and for therapeutic applications. miRNAs are small noncoding endogenous RNA sequences active in the regulation of protein expression, and alteration of miRNA expression can result in a dysregulation of key genes and pathways that contribute to disease development. Indeed, the involvement of exosomal miRNAs has been highlighted in various neurodegenerative diseases, and this opens the possibility that dysregulated exosomal miRNA profiles may influence AD disease. The advances in exosome-related biomarker detection in AD are summarized. Finally, in this review, we highlight the use of exosomal miRNAs as essential biomarkers in preclinical and clinical studies in Alzheimer’s disease, also taking a look at their potential clinical value.

The Effect of Sialic Acid on the Expression of miR-218, NF-kB, MMP-9, and TIMP-1

Sialic acid (N-acetylneuraminic acid, NANA) is found at all cell surfaces of vertebrates. Although it is widely accepted that sialic acid is an essential substrate for brain development via a significant role in nerve transfers, structure of glycosides, and synaptogenesis phenomena, there are some reports on the elevated levels of sialic acid and prevalence of neurodegeneration. Matrix metalloproteases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) are involved in neuroinflammation disorders and produced by many cell types, including activated T cells, macrophages, neurons, astrocytes, and microglial cells. It can be hypothesized that sialic acid may have a potentially critical role in regulation of a wide range of uncovered neurodegeneration factors as its downstream targets. In this study, for the first time, we aimed to analyze the possible effect of the sialic acid solution exposure in the human C118 cell line, which was derived from a human brain astrocytoma (glial cells), on the expression patterns of miR-218, NF-kB, MMP-9, and TIMP-1. For MMP-9, protein levels were studied too. Half maximal inhibitory concentration (IC₅₀) value of NANA was obtained by MTT assay. Glial cell line was treated with sialic acid (300, 500, and 1000 µg/ml) for 24 h to investigate the effects of this ligand on the expression of miR-218, NF-kB, MMP-9, and TIMP-1 genes. Protein levels were checked by Western blotting, and by using zymography, the gelatinolytic activity of MMP-9 secreted into conditioned media was assayed. At 300 µM, 500 µM, and 1000 µM sialic acid treatments, the expression of miR-218 was downregulated; subsequently, the NF-kB, MMP-9, and TIMP-1 genes as well as their protein expressions were upregulated. More interestingly, the enzyme activity of secreted MMP-9 was upregulated too (p-values ≤ 0.05). This study could demonstrate the significant effect of sialic acid on miR-218, NF-kB, MMP-9 , and TIMP-1 expressions in gene and protein levels and also the levels of enzyme activity of secreted MMP-9. Therefore, provided information indicates the novel idea of a possible linkage between sialic acid species and regulation of these neuroinflammation genes in Glial cell line.

Modulation of oligonucleotide-binding dynamics on WS2 nanosheet interfaces for detection of Alzheimer's disease biomarkers

Non-covalent adsorption and desorption of oligonucleotides on two-dimensional nanosheets are widely employed to design nanobiosensors for the rapid optical detection of targets. A precise control over the weak interactions between nanosheet interfaces and oligonucleotides is crucial for a high-sensing performance. Herein, the interface of ultrathin WS₂ nanosheets used as a fluorescence quencher was engineered by four different dextran polymers in an aqueous solution to control the adsorption kinetics and thermodynamics of the DNA probe. The WS₂ nanosheets, functionalized by the carboxyl group-bearing dextran (CM-dex-WS₂) or the trimethylammonium-modified dextran (TMA-dex-WS₂), exhibited 3.6-fold faster adsorption rates of the fluorescein-labeled DNA probe (FAM-DNA), which led to the effective fluorescence quenching of FAM, compared to the nanosheets functionalized with pristine dextran (dex-WS₂) or the hydrophobic phenoxy groups-bearing dextran (PhO-dex-WS₂). Isothermal titration calorimetry measurements showed that the adsorption strength of FAM-DNA for CM-dex-WS₂ was one order of magnitude greater than its hybridization energy for a target microRNA (miR-29a) that is well-known as an Alzheimer's disease (AD) biomarker, leading to the unfavorable desorption of the DNA probe from the surface. In contrast, TMA-dex-WS₂ exhibited the proper adsorption strength of FAM-DNA, which was lower than its hybridization energy for miR-29a, leading to its favorable desorption from the nanosheet surface along with the noticeable restoration of the quenched fluorescence after its hybridization with miR-29a. Finally, the interface modulation of WS₂ nanosheets allowed the selective and sensitive recognition of miR-29a against non-complementary RNA and single base-mismatched RNA in human serum via increases in target-specific fluorescence.

A logical relationship for schizophrenia, bipolar, and major depressive disorder. Part 1: Evidence from chromosome 1 high density association screen

Familial clustering of schizophrenia (SCZ), bipolar disorder (BPD), and major depressive disorder (MDD) was investigated systematically (Aukes et al., Genetics in Medicine, 2012, 14, 338-341) and any two or even three of these disorders could coexist in some families. Furthermore, evidence from symptomatology and psychopharmacology also imply the existence of intrinsic connections between these three major psychiatric disorders. A total of 71,445 SNPs on chromosome 1 were genotyped on 119 SCZ, 253 BPD (type-I), 177 MDD cases and 1000 controls and further validated in 986 SCZ patients in the population of Shandong province of China. Outstanding psychosis genes are systematically revealed( ATP1A4, ELTD1, FAM5C, HHAT, KIF26B, LMX1A, NEGR1, NFIA, NR5A2, NTNG1, PAPPA2, PDE4B, PEX14, RYR2, SYT6, TGFBR3, TTLL7, and USH2A). Unexpectedly, flanking genes for up to 97.09% of the associated SNPs were also replicated in an enlarged cohort of 986 SCZ patients. From the perspective of etiological rather than clinical psychiatry, bipolar, and major depressive disorder could be subtypes of schizophrenia. Meanwhile, the varied clinical feature and prognosis might be the result of interaction of genetics and epigenetics, for example, irreversible or reversible shut down, and over or insufficient expression of certain genes, which may gives other aspects of these severe mental disorders.

Rac1 relieves neuronal injury induced by oxygenglucose deprivation and re-oxygenation via regulation of mitochondrial biogenesis and function

Certain microRNAs (miRNAs) can function as neuroprotective factors after reperfusion/ischemia brain injury. miRNA-142-3p can participate in the occurrence and development of tumors and myocardial ischemic injury by negatively regulating the activity of Rac1, but it remains unclear whether miRNA-142-3p also participates in cerebral ischemia/reperfusion injury. In this study, a model of oxygen-glucose deprivation/re-oxygenation in primary cortical neurons was established and the neurons were transfected with miR-142-3p agomirs or miR-142-3p antagomirs. miR-142-3p expression was down-regulated in neurons when exposed to oxygen-glucose deprivation/re-oxygenation. Over-expression of miR-142-3p using its agomir remarkably promoted cell death and apoptosis induced by oxygen-glucose deprivation/re-oxygenation and improved mitochondrial biogenesis and function, including the expression of peroxisome proliferator-activated receptor-γ coactivator-1α, mitochondrial transcription factor A, and nuclear respiratory factor 1. However, the opposite effects were produced if miR-142-3p was inhibited. Luciferase reporter assays verified that Rac Family Small GTPase 1 (Rac1) was a target gene of miR-142-3p. Over-expressed miR-142-3p inhibited NOX2 activity and expression of Rac1 and Rac1-GTPase (its activated form). miR-142-3p antagomirs had opposite effects after oxygen-glucose deprivation/re-oxygenation. Our results indicate that miR-142-3p down-regulates the expression and activation of Rac1, regulates mitochondrial biogenesis and function, and inhibits oxygen-glucose deprivation damage, thus exerting a neuroprotective effect. The experiments were approved by the Committee of Experimental Animal Use and Care of Central South University, China (approval No. 201703346) on March 7, 2017.

MicroRNA-134-5p inhibition rescues long-term plasticity and synaptic tagging/capture in an Aβ(1-42)-induced model of Alzheimer's disease

Progressive memory loss is one of the most common characteristics of Alzheimer's disease (AD), which has been shown to be caused by several factors including accumulation of amyloid β peptide (Aβ) plaques and neurofibrillary tangles. Synaptic plasticity and associative plasticity, the cellular basis of memory, are impaired in AD. Recent studies suggest a functional relevance of microRNAs (miRNAs) in regulating plasticity changes in AD, as their differential expressions were reported in many AD brain regions. However, the specific role of these miRNAs in AD has not been elucidated. We have reported earlier that late long-term potentiation (late LTP) and its associative mechanisms such as synaptic tagging and capture (STC) were impaired in Aβ (1-42)-induced AD condition. This study demonstrates that expression of miR-134-5p, a brain-specific miRNA is upregulated in Aβ (1-42)-treated AD hippocampus. Interestingly, the loss of function of miR-134-5p restored late LTP and STC in AD. In AD brains, inhibition of miR-134-5p elevated the expression of plasticity-related proteins (PRPs), cAMP-response-element binding protein (CREB-1) and brain-derived neurotrophic factor (BDNF), which are otherwise downregulated in AD condition. The results provide the first evidence that the miR-134-mediated post-transcriptional regulation of CREB-1 and BDNF is an important molecular mechanism underlying the plasticity deficit in AD; thus demonstrating the critical role of miR-134-5p as a potential therapeutic target for restoring plasticity in AD condition.

microRNA-592 blockade inhibits oxidative stress injury in Alzheimer's disease astrocytes via the KIAA0319-mediated Keap1/Nrf2/ARE signaling pathway

MicroRNA-592 (miR-592) has been reported to play a significant role in mediating neuronal activity, but its possible link with Alzheimer's disease (AD) remains unclear. We aimed to explore the mechanism of miR-592 in oxidative stress (OS) injury of astrocytes (ASTs) from AD rat models induced by D-galactose or Aβ_25-35 injection. Bioinformatics website and dual-luciferase reporter gene assay clarified the binding affinity between miR-592 and KIAA0319. KIAA0319 was identified as a target gene of miR-592. The mechanism of miR-592, KIAA0319 and the Keap1/Nrf2/ARE signaling pathway in AD was examined after transducing miR-592 mimic, miR-592 inhibitor and siRNA-KIAA0319 into ASTs to query cell viability, OS injury and reactive oxygen species (ROS). The rat models of AD Exhibited highly expressed miR-592 and poorly expressed KIAA0319. Furthermore, inhibition of miR-592 diminished C-Keap1 expression and enhanced N-Nrf2 and NQO1 expression, thus promoting cell viability and reducing OS injury of ASTs. Taken together, these findings suggested that the downregulation of miR-592 inhibited OS injury of ASTs in rat models of AD by up-regulating KIAA0319 through the activation of the Keap1/Nrf2/ARE signaling pathway.

A comparison of machine learning classifiers for dementia with Lewy bodies using miRNA expression data

Background

Dementia with Lewy bodies (DLB) is the second most common subtype of neurodegenerative dementia in humans following Alzheimer’s disease (AD). Present clinical diagnosis of DLB has high specificity and low sensitivity and finding potential biomarkers of prodromal DLB is still challenging. MicroRNAs (miRNAs) have recently received a lot of attention as a source of novel biomarkers.

Methods

In this study, using serum miRNA expression of 478 Japanese individuals, we investigated potential miRNA biomarkers and constructed an optimal risk prediction model based on several machine learning methods: penalized regression, random forest, support vector machine, and gradient boosting decision tree.

Results

The final risk prediction model, constructed via a gradient boosting decision tree using 180 miRNAs and two clinical features, achieved an accuracy of 0.829 on an independent test set. We further predicted candidate target genes from the miRNAs. Gene set enrichment analysis of the miRNA target genes revealed 6 functional genes included in the DHA signaling pathway associated with DLB pathology. Two of them were further supported by gene-based association studies using a large number of single nucleotide polymorphism markers (BCL2L1: P = 0.012, PIK3R2: P = 0.021).

Conclusions

Our proposed prediction model provides an effective tool for DLB classification. Also, a gene-based association test of rare variants revealed that BCL2L1 and PIK3R2 were statistically significantly associated with DLB.

Plasma expression of miRNA-21, - 214, -34a, and -200a in patients with persistent HPV infection and cervical lesions

Background

To examine differences in the plasma levels of miRNA-21, − 214, −34a, and -200a in patients with persistent high-risk human papillomavirus (hr-HPV) infection or with cervical lesions of different grades.

Methods

Venous blood was collected from 232 individuals to measure the plasma expression levels of miRNA-21, − 214, −34a, and -200a. The subjects included normal controls and patients with persistent hr-HPV infection, CIN1, CIN2, CIN3, or cervical cancer (n = 42, 31, 19, 54, 71, and 15 patients, respectively). Cervical conization specimens were collected from all the women. To ensure the accuracy of histopathology, three consecutive tissue sections with an identical diagnosis were selected, and dissection samples were taken from them for miRNA detection. Eligible cases met the inclusion criteria based on sample observation using the middle slice of sandwich tissue sections from the pathological tissue in accordance with the diagnosis of CIN1, CIN2 and CIN3 in 8, 29, and 26 cases, respectively. The miRNA-21, − 214, −34a, and -200a expression levels in the paraffin-embedded tissue samples were determined. The percentage of patients with a CIN2+ diagnosis at 30–49 years old was significantly different from that of those diagnosed with CIN1. The incidence of CIN2+ patients exposed to passive smoking was significantly different from that of CIN1- patients. The percentage of CIN2+ patients with three pregnancies was significantly different from that of those with CIN1, and the percentage of CIN2+ subjects with ≥4 pregnancies was significantly different from that of CIN1- patients. The number of CIN2+ patients with two or more induced abortions was significantly different from that of patients with CIN1. The percentage of CIN2+ patients who underwent a caesarean section was significantly different from that of patients with CIN. The percentage of CIN2+ patients with first-degree relatives with cancer was significantly different from that of those with CIN1. Among CIN2+ patients, the percentage with a first sexual encounter at ≤20 years old was significantly different from that of those with CIN1. The percentage of CIN2+ patients with ≥2 sexual partners was significantly different from that of CIN1- patients.

Results

The plasma miRNA-214, −34a, and -200a expression levels were decreased in patients with more severe cervical lesions. Plasma miRNA levels in CIN1- patients were significantly different from those in CIN2+ patients. The kappa values for miRNA-21, − 214, −34a and -200a in tissue versus plasma were 0.7122, 0.9998, 0.8986 and 0.7458, respectively. The sensitivity of each biomarker for detecting CIN2 was calculated, and ROC curves of the four miRNA biomarkers were drawn. The AUC of the four plasma miRNAs was greater than 0.5, with the AUC of miRNA-21 being the largest at 0.703. The plasma miRNA expression levels exhibited at least one tie between CIN1 and CIN2. The AUCs for miRNA-21, −34a, −200a and − 214 were 0.613, 0.508, 0.615 and 0.505, respectively.

Conclusions

Changes in plasma miRNA-21, − 214, −34a and -200a levels were associated with cervical lesion severity. The plasma miRNA levels in CIN1- subjects were significantly different from those in CIN2+ subjects. This analysis may help in detection of high-grade cervical lesions.

Deregulated miR-29b-3p Correlates with Tissue-Specific Activation of Intrinsic Apoptosis in An Animal Model of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is one of the most common incurable motor neuron disorders in adults. The majority of all ALS cases occur sporadically (sALS). Symptoms of ALS are caused by a progressive degeneration of motor neurons located in the motor cortex and spinal cord. The question arises why motor neurons selectively degenerate in ALS, while other cells and systems appear to be spared the disease. Members of the intrinsic apoptotic pathway are frequent targets of altered microRNA expression. Therefore, microRNAs and their effects on cell survival are subject of controversial debates. In this study, we investigated the expression of numerous members of the intrinsic apoptotic cascade by qPCR, western blot, and immunostaining in two different regions of the CNS of wobbler mice. Further we addressed the expression of miR-29b-3p targeting BMF, Bax, and, Bak, members of the apoptotic pathway. We show a tissue-specific differential expression of BMF, Bax, and cleaved-Caspase 3 in wobbler mice. An opposing regulation of miR-29b-3p expression in the cerebellum and cervical spinal cord of wobbler mice suggests different mechanisms regulating the intrinsic apoptotic pathway. Based on our findings, it could be speculated that miR-29b-3p might regulate antiapoptotic survival mechanisms in CNS areas that are not affected by neurodegeneration in the wobbler mouse ALS model.

MiR-101 relates to chronic peripheral neuropathic pain through targeting KPNB1 and regulating NF-κB signaling

Accumulating evidences indicates that chronic neuropathic pain is a kind of neuro-immune disorder with enhanced activation of the immune system. Although the prevalence is very high, neuropathic pain remains extremely difficult to cure. miRNAs are a group of short nonprotein coding RNAs, regulating target genes expression via targeting 3'-untranslated region. More and more research indicates that altered miRNAs expression profile relates to the pathogenesis of neuropathic pain. In this study, we firstly detected the expression of six candidate miRNAs in the plasma samples from 23 patients with neuropathic pain and 10 healthy controls. Subsequently, the level of miR-132 and miR-101 was detected in the sural nerve biopsies. We found miR-101 level was significantly repressed in both the plasma samples and sural nerve biopsies from neuropathic pain patients. Predicted by bioinformatics tools and confirmed by dual luciferase assay and immunoblotting, we identified that KPNB1 is a direct target of miR-101. The negative correlation between miR-101 and KPNB1 was also confirmed in the sural nerve biopsies, and miR-101 reduction relates to the activation of NF-κB signaling in vivo and in vitro which contributes to the pathogenesis of neuropathic pain.

1,3,5,8-Tetrahydroxy-9H-xanthen-9-one exerts its antiageing effect through the regulation of stress-response genes and the MAPK signaling pathway

The antioxidative effects of 30 xanthone derivatives (XDs) (XD-n, n = 1-30) in HepG2 cells were evaluated by the cellular antioxidant activity assay. Results showed that all XDs were antioxidants and 1,3,5,8-tetrahydroxy-9H-xanthen-9-one (XD-2) was the most active antioxidant. The all-oxygenated substituted xanthones extended the lifespan of wild-type N2 nematodes under normal culture conditions and XD-2 was the best one. XD-2 eliminated excessive intracellular reactive oxygen species and enhanced the expression levels and activities of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase. XD-2 inhibited the H₂ O₂ -increased phosphorylation levels of c-JUN N-terminal kinase, extracellular signal-regulated kinase, and p38 in HepG2 cells. In vivo, XD-2 also extended the lifespan of wild-type N2 nematodes under oxidative stress induced by paraquat, but failed in extending the lifespan of CF1038 (daf-16 deletion) and AY102 (pmk-1 deletion) mutant nematodes. It was revealed by real-time polymerase chain reaction that the genes daf-16, sir-2.1, akt-1, and age-1 were all inhibited by paraquat stimuli, while XD-2 reversed these inhibitions; in contrast, paraquat stimuli upregulated both the skn-1 and pmk-1 genes. However, treatment by XD-2 further increased the levels of both genes. These pieces of evidence implied that XD-2 promotes longevity through endogenous signaling pathways rather than through the antioxidative activity alone. Taken all together, it may be concluded that XD-2 is a promising antiageing agent.

Lentivirus-mediated microRNA-26a-modified neural stem cells improve brain injury in rats with cerebral palsy

This study is launched to investigate the effect of lentivirus-mediated microRNA-26a (miR-26a)-modified neural stem cells (NSCs) in brain injury in rats with cerebral palsy (CP). The successfully constructed miR-26a lentivirus expression vector and empty vector virus were used to modify NSCs. The model of CP with ischemia and anoxia was established in rats. NSCs and miR-26a-NSCs were stereoscopically injected into the cerebral cortex of the modeled rats, respectively. The survival and migration of NSCs infected with recombinant lentivirus expressing green fluorescence in vivo was observed under a light microscope. The neurobehavioral functions, morphology, and ultrastructure of cerebral cortex and hippocampus, apoptosis of brain cells, expression of apoptosis-related protein caspase-3 and Bax, together with the expression of the glial fibrillary acidic protein (GFAP) in cerebral cortex and hippocampus were determined. Expression of miR-26a in NSCs infected with plVTHM-miR-26a increased significantly. After NSCs transplantation, the neurobehavioral status of CP rats was improved, the degree of brain pathological injury was alleviated, the apoptotic index of cells in cerebral cortex and hippocampus and the expression of the apoptotic protein (caspase-3 and Bax) were decreased, the expression of GFAP were significantly decreased. After miR-26a-NSCs transplantation, these aforementioned results further improved or decreased. Our study suggests that miR-26a-modified NSCs mediated by lentivirus can improve brain injury, inhibit apoptosis of brain cells and activation of astrocytes in CP rats.

Extracellular vesicle‑delivered miR‑505‑5p, as a diagnostic biomarker of early lung adenocarcinoma, inhibits cell apoptosis by targeting TP53AIP1

Lung adenocarcinoma (LA) is the most commonly occurring histological type of non‑small cell lung cancer. Diagnosis and treatment of LA remain a major clinical challenge. In the present study, to identify early LA biomarkers, extracellular vesicles (EVs) were separated from the plasma samples from 153 patients with LA and 75 healthy controls. microRNA (miRNA) expression profiling was performed at the screening stage (5 patients with LA vs. 5 controls), followed by verification at the validation stage (40 patients with LA vs. 20 controls) using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). The four disordered miRNAs (miR‑505‑5p, miR‑486‑3p, miR‑486‑3p and miR‑382‑3p) identified in the plasma EVs were further evaluated at the testing stage (108 patients with LA vs. 50 controls) by RT‑qPCR. It was revealed that miR‑505‑5p was upregulated, whereas miR‑382‑3p was downregulated, in the EVs from patients with LA. Furthermore, miR‑505‑5p was also upregulated in tumor tissues, compared with adjacent non‑tumor control tissues. Subsequently, the direct targets of miR‑505‑5p were predicted using bioinformatics analyses, and verified by luciferase assay and immunoblotting. The present study determined that miR‑505‑5p functions as an oncogene, promoting lung cancer cell proliferation and inhibiting cancer cell apoptosis via the targeting of tumor protein P53‑regulated apoptosis‑inducing protein 1 (TP53AIP1). Finally, it was confirmed that miR‑505‑5p in plasma EVs could be delivered to lung cancer cells, inhibiting cell apoptosis and promoting cell proliferation by targeting TP53AIP1. In conclusion, the present study indicated that miRNA‑505‑5p functions as an oncogene that may be used as a novel biomarker for the diagnosis and treatment of LA.

Risk prediction models for dementia constructed by supervised principal component analysis using miRNA expression data

Alzheimer's disease (AD) is the most common subtype of dementia, followed by Vascular Dementia (VaD), and Dementia with Lewy Bodies (DLB). Recently, microRNAs (miRNAs) have received a lot of attention as the novel biomarkers for dementia. Here, using serum miRNA expression of 1,601 Japanese individuals, we investigated potential miRNA biomarkers and constructed risk prediction models, based on a supervised principal component analysis (PCA) logistic regression method, according to the subtype of dementia. The final risk prediction model achieved a high accuracy of 0.873 on a validation cohort in AD, when using 78 miRNAs: Accuracy = 0.836 with 86 miRNAs in VaD; Accuracy = 0.825 with 110 miRNAs in DLB. To our knowledge, this is the first report applying miRNA-based risk prediction models to a dementia prospective cohort. Our study demonstrates our models to be effective in prospective disease risk prediction, and with further improvement may contribute to practical clinical use in dementia.

Comprehensive analysis of the lncRNA-associated ceRNA network identifies neuroinflammation biomarkers for Alzheimer's disease

Accumulating evidence has highlighted the important roles of long non-coding RNAs (lncRNAs) acting as competing endogenous RNAs (ceRNAs) in Alzheimer's disease (AD).

A novel mechanism of synaptic and cognitive impairments mediated via microRNA-30b in Alzheimer's disease

BACKGROUND

It is widely accepted that cognitive and memory deficits in Alzheimer's disease (AD) primarily result from synaptic failure. However, the mechanisms that underlie synaptic and cognitive dysfunction remain unclear.

METHODS

We utilized molecular biology techniques, electrophysiological recordings, fluorescence in situ hybridization (FISH), immuno- and Golgi-staining, chromatin immunoprecipitation (CHIP); lentivirus (LV)-based microRNA overexpression and 'sponging', and behavioral tests to assess upregulated miR-30b causing synaptic and cognitive declines in APP transgenic (TG) mice.

FINDINGS

We provide evidence that expression of miR-30b, which targets molecules important for maintaining synaptic integrity, including ephrin type-B receptor 2 (ephB2), sirtuin1 (sirt1), and glutamate ionotropic receptor AMPA type subunit 2 (GluA2), is robustly upregulated in the brains of both AD patients and APP transgenic (TG) mice, an animal model of AD, while expression of its targets is significantly downregulated. Overexpression of miR-30b in the hippocampus of normal wild-type (WT) mice impairs synaptic and cognitive functions, mimicking those seen in TG mice. Conversely, knockdown of endogenous miR-30b in TG mice prevents synaptic and cognitive decline. We further observed that expression of miR-30b is upregulated by proinflammatory cytokines and Aβ42 through NF-κB signaling.

INTERPRETATION

Our results provide a previously undefined mechanism by which unregulated miR-30b causes synaptic and cognitive dysfunction in AD, suggesting that reversal of dysregulated miR-30b in the brain may prevent or slow cognitive declines in AD. FUND: This work was supported by National Institutes of Health grants R01NS076815, R01MH113535, R01AG058621, P30GM103340 Pilot Project, and by the LSUHSC School of Medicine Research Enhancement Program grant (to C.C.).

FMSM: a novel computational model for predicting potential miRNA biomarkers for various human diseases

Background

MicroRNA (miRNA) plays a key role in regulation mechanism of human biological processes, including the development of disease and disorder. It is necessary to identify potential miRNA biomarkers for various human diseases. Computational prediction model is expected to accelerate the process of identification.

Results

Considering the limitations of previously proposed models, we present a novel computational model called FMSM. It infers latent miRNA biomarkers involved in the mechanism of various diseases based on the known miRNA-disease association network, miRNA expression similarity, disease semantic similarity and Gaussian interaction profile kernel similarity. FMSM achieves reliable prediction performance in 5-fold and leave-one-out cross validations with area under ROC curve (AUC) values of 0.9629+/− 0.0127 and 0.9433, respectively, which outperforms the state-of-the-art competitors and classical algorithms. In addition, 19 of top 25 predicted miRNAs have been validated to have associations with Colonic Neoplasms in case study.

Conclusions

A factored miRNA similarity based model and miRNA expression similarity substantially contribute to the well-performing prediction. The list of the predicted most latent miRNA biomarkers of various human diseases is publicized. It is anticipated that FMSM could serve as a useful tool guiding the future experimental validation for those promising miRNA biomarker candidates.

Electronic supplementary material

The online version of this article (10.1186/s12918-018-0664-9) contains supplementary material, which is available to authorized users.

Temporal Integrative Analysis of mRNA and microRNAs Expression Profiles and Epigenetic Alterations in Female SAMP8, a Model of Age-Related Cognitive Decline

A growing body of research shows that epigenetic mechanisms are critically involved in normal and pathological aging. The Senescence-Accelerated Mouse Prone 8 (SAMP8) can be considered a useful tool to better understand the dynamics of the global epigenetic landscape during the aging process since its phenotype is not fully explained by genetic factors. Here we investigated dysfunctional age-related transcriptional profiles and epigenetic programming enzymes in the hippocampus of 2- and 9-month-old SAMP8 female mice using the Senescent-Accelerated Resistant 1 (SAMR1) mouse strain as control. SAMP8 mice presented 1,062 genes dysregulated at 2 months of age, and 1,033 genes at 9 months, with 92 genes concurrently dysregulated at both ages compared to age-matched SAMR1. SAMP8 mice showed a significant decrease in global DNA methylation (5-mC) at 2 months while hydroxymethylation (5-hmC) levels were increased in SAMP8 mice at 2 and 9 months of age compared to SAMR1. These changes were accompanied by changes in the expression of several enzymes that regulate 5-mC and methylcytosine oxidation. Acetylated H3 and H4 histone levels were significantly diminished in SAMP8 mice at 2-month-old compared to SAMR1 and altered Histone DeACetylase (HDACs) profiles were detected in both young and old SAMP8 mice. We analyzed 84 different mouse miRNAs known to be altered in neurological diseases or involved in neuronal development. Compared with SAMR1, SAMP8 mice showed 28 and 17 miRNAs differentially expressed at 2 and 9 months of age, respectively; 6 of these miRNAs overlapped at both ages. We used several bioinformatic approaches to integrate our data in mRNA:miRNA regulatory networks and functional predictions for young and aged animals. In sum, our study reveals interplay between epigenetic mechanisms and gene networks that seems to be relevant for the progression toward a pathological aging and provides several potential markers and therapeutic candidates for Alzheimer's Disease (AD) and age-related cognitive impairment.

Revealing post-transcriptional microRNA-mRNA regulations in Alzheimer's disease through ensemble graphs

BACKGROUND

In silico investigations on the integration of multiple datasets are in need of higher statistical power methods to unveil secondary findings that were hidden from the initial analyses. We present here a novel method for the network analysis of messenger RNA post-translational regulation by microRNA molecules. The method integrates expression data and sequence binding predictions through a set of sound machine learning techniques, forwarding all results to an ensemble graph of regulations.

RESULTS

Bayesian network classifiers are induced based on a pool of ensemble graphs with ascending order of complexity. Individual goodness-of-fit and classification performances are evaluated for each learned model. As a testbed, four Alzheimer's disease datasets are integrated using the new approach, achieving top values of 0.9794 ± 0.01 for the area under the receiver operating characteristic curve and 0.9439 ± 0.0234 for the prediction accuracy.

CONCLUSIONS

Post-transcriptional regulations found by the optimal network classifier concur with previous literature findings. Furthermore, additional network structures suggest previously unreported regulations in the state of the art of Alzheimer's research. The quantitative performance as well as sound biological findings provide confidence in the ensemble approach and encourage similar integrative analyses for other conditions.

Serum-based microRNA biomarkers for major depression: MiR-16, miR-135a, and miR-1202

Background

Depression is a common medical condition with a high prevalence leading to emotional abnormality. Despite some drawbacks, depression currently diagnosed using a combination of patient interviews and self-report questionnaires. Recently, there is emerging emphasis to establish biomarkers to diagnosis and clinical management of depression. This case-control study was designed to develop microRNA (miRNA)-based serum biomarker for depression.

Materials and Methods

In this study, 39 patients with depression and 36 healthy controls were enrolled. Serum miRNAs gene expression was measured using real-time polymerase chain reaction (PCR) analysis; finally, the data represent as the 2^-ΔCt followed by further statistical analysis.

Results

The serum level of miR-16 was significantly (P < 0.001) down-regulated (mean: 0.9123 and standard deviation [SD]: 0.06) in compared to normal individuals (mean: 1.6848 and SD: 0.09). The concentration of miR-135a was also catastrophically decreased (P < 0.001) in the patients (mean: 1.160 and SD: 0.07) in compared to control (mean: 1.819 and SD: 0.09). The relative miR-1202 expression levels were significantly lower (P < 0.001) in the patients (mean: 0.1755 and SD: 0.01) than in the healthy individuals (mean: 0.2939 and SD: 0.01). The receiver operating characteristic curve analysis indicated the obvious separation between patient and healthy control, with an AUC of 0.75 (95% confidence interval [CI] = 0.642-0.858, P < 0.001), 0.72 (95% CI = 0.607-0.834, P < 0.001), and 0.74 (95% CI = 0.630-0.861, P < 0.001) for miR-16, miR-135a, and miR-1202, respectively. The data suggest that these miRNAs have a potential to be used as a biomarker of depression with sensitivity 77.8% and specificity of 61.5% for miR-16, 94.4% and 41.0% for miR-135a as well as 86.1% and 61.5% for miR-1202, respectively (P < 0.001).

Conclusion

Our findings showed that these miRNA can be used as a biomarker of depression diagnosis. MiR-135a and miR-1202 exhibited better sensitivity and specificity, respectively.

Up-regulated miR-192-5p expression rescues cognitive impairment and restores neural function in mice with depression via the Fbln2-mediated TGF-β1 signaling pathway

Depression represents a condition characterized by cognitive deficits and neural dysfunction and has recently been correlated with microRNAs (miRs) and their respective target genes. The present study was conducted with the goal of investigating the expression of miR-192-5p and its target gene fibulin (Fbln)-2 in an attempt to evaluate their roles in the occurrence and progression of cognitive impairment and neural function in mice with chronic unpredictable mild stress (CUMS)-induced depression through regulation of the TGF-β1 signal transduction pathway. Verification of the targeting relationship between miR-192-5p and Fbln2 was provided in the form of initial bioinformatics prediction, followed by a further verification in the form of a dual-luciferase reporter gene assay. Normal mice and models induced by CUMS were assigned into various groups, whereas mimics, inhibitors, and small interfering RNA were introduced to validate the regulatory mechanism by which miR-192-5p regulates Fbln2 depression. Novel object recognition, tail suspension testing, and Morris water maze were all employed 28 d after transfection. Hippocampal electrophysiological recordings, Golgi staining, HPLC mass spectrometry, and fluorescence immunohistochemistry were performed to further evaluate cognitive function and neuron regeneration. CUMS-induced depression was determined to represent a predisposing factor for cognitive impairment and damage to neural function in mice, highlighted by novel object recognition, learning and memory abilities, population spike amplitude, synaptic transmission, cAMP levels, neuronal regeneration, and increased behavioral changes that resemble depression. Furthermore, increased Fbln2 expression, an activated TGF-β1 signaling pathway, and decreased expression of miR-192-5p, synaptophysin, brain-derived neurotrophic factor, N-methyl-d-aspartate receptor subunit 2B, and calmodulin-dependent protein kinase II were noted. Up-regulated miR-192-5p targeting Fbln2 acts to alleviate CUMS-induced depression by inhibiting the TGF-β1 signaling pathway, resulting in the enhanced cognitive function in novel object recognition, learning and memory ability, population spike amplitude, synaptic transmission, neuron regeneration, and alleviation of behavioral symptoms. The central findings of the present study indicate that up-regulated levels of miR-192-5p expression act to suppress activation of the TGF-β1 signaling pathway by means of binding to Fbln2, thereby ameliorating cognitive impairment and strengthening neural function in a mouse model of depression.-Tang, C.-Z., Yang, J.-T., Liu, Q.-H., Wang, Y.-R., Wang, W.-S. Up-regulated miR-192-5p expression rescues cognitive impairment and restores neural function in mice with depression via the Fbln2-mediated TGF-β1 signaling pathway.

Role of Melt Curve Analysis in Interpretation of Nutrigenomics' MicroRNA Expression Data

This article illustrates the importance of melt curve analysis (MCA) in interpretation of mild nutrogenomic micro(mi)RNA expression data, by measuring the magnitude of the expression of key miRNA molecules in stool of healthy human adults as molecular markers, following the intake of Pomegranate juice (PGJ), functional fermented sobya (FS), rich in potential probiotic lactobacilli, or their combination. Total small RNA was isolated from stool of 25 volunteers before and following a three-week dietary intervention trial. Expression of 88 miRNA genes was evaluated using Qiagen's 96 well plate RT² miRNA qPCR arrays. Employing parallel coordinates plots, there was no observed significant separation for the gene expression (Cq) values, using Roche 480® PCR LightCycler instrument used in this study, and none of the miRNAs showed significant statistical expression after controlling for the false discovery rate. On the other hand, melting temperature profiles produced during PCR amplification run, found seven significant genes (miR-184, miR-203, miR-373, miR-124, miR-96, miR-373 and miR-301a), which separated candidate miRNAs that could function as novel molecular markers of relevance to oxidative stress and immunoglobulin function, for the intake of polyphenol (PP)-rich, functional fermented foods rich in lactobacilli (FS), or their combination. We elaborate on these data, and present a detailed review on use of melt curves for analyzing nutigenomic miRNA expression data, which initially appear to show no significant expressions, but are actually more subtle than this simplistic view, necessitating the understanding of the role of MCA for a comprehensive understanding of what the collective expression and MCA data collectively imply.

Altered Micro-RNA Regulation and Neuroprotection Activity of Eremostachys labiosiformis in Alzheimer's Disease Model

Background

Amyloid-β peptide (Aβ) is involved in the formation of senile plaques in Alzheimer's disease (AD), and causes neuronal cell death by inducing oxidative stress.

Objective

We investigated the protective effect of Eremostachys labiosiformis extract against the Aβ-induced toxicity in SH-SY5Y cells.

Methods

Methanolic extract from the aerial parts of E. labiosiformis was prepared by percolation method at room temperature. SH-SY5Y cells were treated and incubated with different concentrations of the extract for 1 h, before addition of Aβ. Cytotoxicity was measured 24 h after the addition of Aβ to the medium using MTT and reactive oxygen species (ROS) assays. Effective doses were evaluated using real-time polymerase chain reaction to evaluate expression of miR-212 and miR-132. The results were analyzed using SPSS software (16).

Results

Exposure of -SH-SY5Y cells to Aβ significantly affected the viability of cells and increased ROS levels. The results revealed that 1.2 and 2.5 μg/mL of the E. labiosiformis extract reduced Aβ-induced deterioration. Only 2.5 μg/mL of the extract could reduce ROS levels. In addition, 5 μg/mL of the extract increased the expression of the miRNAs, which was reduced after exposure to Aβ.

Conclusion

Based on the antioxidant and protective effects of the E. labiosiformis extract on expression of miR-132 and miR-212 and ROS level, this herb could be used as a suitable candidate for future studies on neurodegenerative diseases including AD.

MicroRNAs, Long Noncoding RNAs, and Their Functions in Human Disease

Majority of the human genome is transcribed into RNAs with absent or limited protein-coding potential. microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are two major families of the non-protein-coding transcripts. miRNAs and lncRNAs can regulate fundamental cellular processes via diverse mechanisms. The expression and function of miRNAs and lncRNAs are tightly regulated in development and physiological homeostasis. Dysregulation of miRNAs and lncRNAs is critical to pathogenesis of human disease. Moreover, recent evidence indicates a cross talk between miRNAs and lncRNAs. Herein we review recent advances in the biology of miRNAs and lncRNAs with respect to the above aspects. We focus on their roles in cancer, respiratory disease, and neurodegenerative disease. The complexity, flexibility, and versatility of the structures and functions of miRNAs and lncRNAs demand integration of experimental and bioinformatics tools to acquire sufficient knowledge for applications of these noncoding RNAs in clinical care.