Identification of a common lupus disease-associated microRNA expression pattern in three different murine models of lupus

Background

Recent reports have shown that microRNAs (miRNAs) regulate vital immunological processes and have emerged as key regulators of immune system development and function. Therefore, it is important to determine miRNA dysregulation and its pathogenic contribution in autoimmune diseases, an aspect not adequately addressed thus far.

Methodology/Principal Findings

In this study, we profiled miRNA expressions in splenic lymphocytes from three murine lupus models (MRL-lpr, B6-lpr and NZB/W_F1) with different genetic background by miRNA microarray assays and Real-time RT-PCR. Despite the genetic differences among these three lupus stains, a common set of dysregulated miRNAs (miR-182-96-183 cluster, miR-31, and miR-155) was identified in splenocytes when compared with age-matched control mice. The association of these miRNAs with the disease was highlighted by our observation that this miRNA expression pattern was evident in NZB/W mice only at an age when lupus disease is manifested. Further, we have shown that the miRNA dysregulation in MRL-lpr mice was not simply due to the activation of splenocytes. By Real-time RT-PCR, we confirmed that these miRNAs were upregulated in both purified splenic B and T cells from MRL-lpr mice. miR-127 and miR-379, which were greatly upregulated in splenocytes from lpr mice, were moderately increased in diseased NZB/W mice. In addition, Real-time RT-PCR revealed that miR-146a, miR-101a, and miR-17-92 were also markedly upregulated in splenic T, but not B cells from MRL-lpr mice.

Conclusions/Significance

The identification of common lupus disease-associated miRNAs now forms the basis for the further investigation of the pathogenic contribution of these miRNAs in autoimmune lupus, which will advance our knowledge of the role of miRNAs in autoimmunity. Given that miRNAs are conserved, with regard to both evolution and function, our observation of a common lupus disease-associated miRNA expression pattern in murine lupus models is likely to have significant pathogenic, diagnostic, and/or therapeutic implications in human lupus.     

Deregulation of neuronal miRNAs induced by amyloid-β or TAU pathology

Background

Despite diverging levels of amyloid-β (Aβ) and TAU pathology, different mouse models, as well as sporadic AD patients show predictable patterns of episodic memory loss. MicroRNA (miRNA) deregulation is well established in AD brain but it is unclear whether Aβ or TAU pathology drives those alterations and whether miRNA changes contribute to cognitive decline.

Methods

miRNAseq was performed on cognitively intact (4 months) and impaired (10 months) male APPtg (APP^swe/PS1^L166P) and TAUtg (THY-Tau22) mice and their wild-type littermates (APPwt and TAUwt). We analyzed the hippocampi of 12 mice per experimental group (n =?96 in total), and employed a 2-way linear model to extract differentially expressed miRNAs. Results were confirmed by qPCR in a separate cohort of 4 M and 10 M APPtg and APPwt mice (n =?7–9 per group) and in human sporadic AD and non-demented control brain. Fluorescent in situ hybridization identified their cellular expression. Functional annotation of predicted targets was performed using GO enrichment. Behavior of wild-type mice was assessed after intracerebroventricular infusion of miRNA mimics.

Results

Six miRNAs (miR-10a-5p, miR-142a-5p, miR-146a-5p, miR-155-5p, miR-211-5p, miR-455-5p) are commonly upregulated between APPtg and TAUtg mice, and four of these (miR-142a-5p, miR-146a-5p, miR-155-5p and miR-455-5p) are altered in AD patients. All 6 miRNAs are strongly enriched in neurons. Upregulating these miRNAs in wild-type mice is however not causing AD-related cognitive disturbances.

Conclusion

Diverging AD-related neuropathologies induce common disturbances in the expression of neuronal miRNAs. 4 of these miRNAs are also upregulated in AD patients. Therefore these 4 miRNAs (miR-142a-5p, miR-146a-5p, miR-155-5p and miR-455-5p) appear part of a core pathological process in AD patients and APPtg and TAUtg mice. They are however not causing cognitive disturbances in wild-type mice. As some of these miRNA target AD relevant proteins, they may be, in contrast, part of a protective response in AD.

     

Age and sex differences in kidney microRNA expression during the life span of F344 rats

Background

Growing evidence suggests that epigenetic mechanisms of gene regulation may play a role in susceptibilities to specific toxicities and adverse drug reactions. MiRNAs in particular have been shown to be important regulators in cancer and other diseases and show promise as predictive biomarkers for diagnosis and prognosis. In this study, we characterized the global kidney miRNA expression profile in untreated male and female F344 rats throughout the life span. These findings were correlated with sex-specific susceptibilities to adverse renal events, such as male-biased renal fibrosis and inflammation in old age.

Methods

Kidney miRNA expression was examined in F344 rats at 2, 5, 6, 8, 15, 21, 78, and 104 weeks of age in both sexes using Agilent miRNA microarrays. Differential expression was determined using filtering criteria of ≥1.5 fold change and ANOVA or pairwise t-test (FDR <5%) to determine significant age and sex effects, respectively. Pathway analysis software was used to investigate the possible roles of these target genes in age- and sex-specific differences.

Results

Three hundred eleven miRNAs were found to be expressed in at least one age and sex. Filtering criteria revealed 174 differentially expressed miRNAs in the kidney; 173 and 34 miRNAs exhibiting age and sex effects, respectively. Principal component analysis revealed age effects predominated over sex effects, with 2-week miRNA expression being much different from other ages. No significant sexually dimorphic miRNA expression was observed from 5 to 8 weeks, while the most differential expression (13 miRNAs) was observed at 21 weeks. Potential target genes of these differentially expressed miRNAs were identified.

Conclusions

The expression of 56% of detected renal miRNAs was found to vary significantly with age and/or sex during the life span of F344 rats. Pathway analysis suggested that 2-week-expressed miRNAs may be related to organ and cellular development and proliferation pathways. Male-biased miRNA expression at older ages correlated with male-biased renal fibrosis and mononuclear cell infiltration. These miRNAs showed high representation in renal inflammation and nephritis pathways, and included miR-214, miR-130b, miR-150, miR-223, miR-142-5p, miR-185, and miR-296*. Analysis of kidney miRNA expression throughout the rat life span will improve the use of current and future renal biomarkers and inform our assessments of kidney injury and disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13293-014-0019-1) contains supplementary material, which is available to authorized users.     

Mirna expression profiles identify drivers in colorectal and pancreatic cancers

Background and Aim

Altered expression of microRNAs (miRNAs) hallmarks many cancer types. The study of the associations of miRNA expression profile and cancer phenotype could help identify the links between deregulation of miRNA expression and oncogenic pathways.

Methods

Expression profiling of 866 human miRNAs in 19 colorectal and 17 pancreatic cancers and in matched adjacent normal tissues was investigated. Classical paired t-test and random forest analyses were applied to identify miRNAs associated with tissue-specific tumors. Network analysis based on a computational approach to mine associations between cancer types and miRNAs was performed.

Results

The merge between the two statistical methods used to intersect the miRNAs differentially expressed in colon and pancreatic cancers allowed the identification of cancer-specific miRNA alterations. By miRNA-network analysis, tissue-specific patterns of miRNA deregulation were traced: the driving miRNAs were miR-195, miR-1280, miR-140-3p and miR-1246 in colorectal tumors, and miR-103, miR-23a and miR-15b in pancreatic cancers.

Conclusion

MiRNA expression profiles may identify cancer-specific signatures and potentially useful biomarkers for the diagnosis of tissue specific cancers. miRNA-network analysis help identify altered miRNA regulatory networks that could play a role in tumor pathogenesis.     

Profiling microRNAs in individuals at risk of progression to rheumatoid arthritis

Background

Individuals at risk of rheumatoid arthritis (RA) demonstrate systemic autoimmunity in the form of anti-citrullinated peptide antibodies (ACPA). MicroRNAs (miRNAs) are implicated in established RA. This study aimed to (1) compare miRNA expression between healthy individuals and those at risk of and those that develop RA, (2) evaluate the change in expression of miRNA from “at-risk” to early RA and (3) explore whether these miRNAs could inform a signature predictive of progression from “at-risk” to RA.

Methods

We performed global profiling of 754 miRNAs per patient on a matched serum sample cohort of 12 anti-cyclic citrullinated peptide (CCP)?+?“at-risk” individuals that progressed to RA. Each individual had a serum sample from baseline and at time of detection of synovitis, forming the matched element. Healthy controls were also studied. miRNAs with a fold difference/fold change of four in expression level met our primary criterion for selection as candidate miRNAs. Validation of the miRNAs of interest was conducted using custom miRNA array cards on matched samples (baseline and follow up) in 24 CCP+ individuals; 12 RA progressors and 12 RA non-progressors.

Results

We report on the first study to use matched serum samples and a comprehensive miRNA array approach to identify in particular, three miRNAs (miR-22, miR-486-3p, and miR-382) associated with progression from systemic autoimmunity to RA inflammation. MiR-22 demonstrated significant fold difference between progressors and non-progressors indicating a potential biomarker role for at-risk individuals.

Conclusions

This first study using a cohort with matched serum samples provides important mechanistic insights in the transition from systemic autoimmunity to inflammatory disease for future investigation, and with further evaluation, might also serve as a predictive biomarker.

     

Epithelial-specific histone modification of the <Emphasis Type="Italic">miR-96/182</Emphasis> locus targeting <Emphasis Type="Italic">AMAP1</Emphasis> mRNA predisposes p53 to suppress cell invasion in epithelial cells

Background

TP53 mutations in cancer cells often evoke cell invasiveness, whereas fibroblasts show invasiveness in the presence of intact TP53. AMAP1 (also called DDEF1 or ASAP1) is a downstream effector of ARF6 and is essential for the ARF6-driven cell-invasive phenotype. We found that AMAP1 levels are under the control of p53 (TP53 gene product) in epithelial cells but not in fibroblasts, and here addressed that molecular basis of the epithelial-specific function of p53 in suppressing invasiveness via targeting AMAP1.

Methods

Using MDA-MB-231 cells expressing wild-type and p53 mutants, we identified miRNAs in which their expression is controlled by normal-p53. Among them, we identified miRNAs that target AMAP1 mRNA, and analyzed their expression levels and epigenetic statuses in epithelial cells and nonepithelial cells.

Results

We found that normal-p53 suppresses AMAP1 mRNA in cancer cells and normal epithelial cells, and that more than 30 miRNAs are induced by normal-p53. Among them, miR-96 and miR-182 were found to target the 3′-untranslated region of AMAP1 mRNA. Fibroblasts did not express these miRNAs at detectable levels. The ENCODE dataset demonstrated that the promoter region of the miR-183-96-182 cistron is enriched with H3K27 acetylation in epithelial cells, whereas this locus is enriched with H3K27 trimethylation in fibroblasts and other non-epithelial cells. miRNAs, such as miR-423, which are under the control of p53 but not associated with AMAP1 mRNA, demonstrated similar histone modifications at their gene loci in epithelial cells and fibroblasts, and were expressed in these cells.

Conclusion

Histone modifications of certain miRNA loci, such as the miR-183-96-182 cistron, are different between epithelial cells and non-epithelial cells. Such epithelial-specific miRNA regulation appears to provide the molecular basis for the epithelial-specific function of p53 in suppressing ARF6-driven invasiveness.

     

Altered miRNA expression in canine retinas during normal development and in models of retinal degeneration

Background

Although more than 246 loci/genes are associated with inherited retinal diseases, the mechanistic events that link genetic mutations to photoreceptor cell death are poorly understood. miRNAs play a relevant role during retinal development and disease. Thus, as a first step in characterizing miRNA involvement during disease expression and progression, we examined miRNAs expression changes in normal retinal development and in four canine models of retinal degenerative disease.

Results

The initial microarray analysis showed that 50 miRNAs were differentially expressed (DE) early (3 vs. 7 wks) in normal retina development, while only 2 were DE between 7 and 16 wks, when the dog retina is fully mature. miRNA expression profiles were similar between dogs affected with xlpra2, an early-onset retinal disease caused by a microdeletion in RPGRORF15, and normal dogs early in development (3 wks) and at the peak of photoreceptor death (7 wks), when only 2 miRNAs were DE. However, the expression varied much more markedly during the chronic cell death stage at 16 wks (118 up-/55 down-regulated miRNAs). Functional analyses indicated that these DE miRNAs are associated with an increased inflammatory response, as well as cell death/survival. qRT-PCR of selected apoptosis-related miRNAs (“apoptomirs”) confirmed the microarray results in xlpra2, and extended the analysis to the early-onset retinal diseases rcd1 (PDE6B-mutation) and erd (STK38L-mutation), as well as the slowly progressing prcd (PRCD-mutation). The results showed up-regulation of anti-apoptotic (miR-9, -19a, -20, -21, -29b, -146a, -155, -221) and down-regulation of pro-apoptotic (miR-122, -129) apoptomirs in the early-onset diseases and, with few exceptions, also in the prcd-mutants.

Conclusions

Our results suggest that apoptomirs might be expressed by diseased retinas in an attempt to counteract the degenerative process. The pattern of expression in diseased retinas mirrored the morphology and cell death kinetics previously described for these diseases. This study suggests that common miRNA regulatory mechanisms may be involved in retinal degeneration processes and provides attractive opportunities for the development of novel miRNA-based therapies to delay the progression of the degenerative process.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-172) contains supplementary material, which is available to authorized users.     

Microrna expression signatures predict patient progression and disease outcome in pediatric embryonal central nervous system neoplasms

Background

Although, substantial experimental evidence related to diagnosis and treatment of pediatric central nervous system (CNS) neoplasms have been demonstrated, the understanding of the etiology and pathogenesis of the disease remains scarce. Recent microRNA (miRNA)-based research reveals the involvement of miRNAs in various aspects of CNS development and proposes that they might compose key molecules underlying oncogenesis. The current study evaluated miRNA differential expression detected between pediatric embryonal brain tumors and normal controls to characterize candidate biomarkers related to diagnosis, prognosis and therapy.

Methods

Overall, 19 embryonal brain tumors; 15 Medulloblastomas (MBs) and 4 Atypical Teratoid/Rabdoid Tumors (AT/RTs) were studied. As controls, 13 samples were used; The First-Choice Human Brain Reference RNA and 12 samples from deceased children who underwent autopsy and were not present with any brain malignancy. RNA extraction was carried out using the Trizol method, whilst miRNA extraction was performed with the mirVANA miRNA isolation kit. The experimental approach included miRNA microarrays covering 1211 miRNAs. Quantitative Real-Time Polymerase Chain Reaction was performed to validate the expression profiles of miR-34a and miR-601 in all 32 samples initially screened with miRNA microarrays and in an additional independent cohort of 30 patients (21MBs and 9 AT/RTs). Moreover, meta-analyses was performed in total 27 embryonal tumor samples; 19 MBs, 8 ATRTs and 121 control samples. Twelve germinomas were also used as an independent validation cohort. All deregulated miRNAs were correlated to patients’ clinical characteristics and pathological measures.

Results

In several cases, there was a positive correlation between individual miRNA expression levels and laboratory or clinical characteristics. Based on that, miR-601 could serve as a putative tumor suppressor gene, whilst miR-34a as an oncogene. In general, miR-34a demonstrated oncogenic roles in all pediatric embryonal CNS neoplasms studied.

Conclusions

Deeper understanding of the aberrant miRNA expression in pediatric embryonal brain tumors might aid in the development of tumor-specific miRNA signatures, which could potentially afford promising biomarkers related to diagnosis, prognosis and patient targeted therapy.

     

Whole blood-derived microRNA signatures in mice exposed to lipopolysaccharides

Background

Lipopolysaccharide (LPS) is recognized as the most potent microbial mediator presaging the threat of invasion of Gram-negative bacteria that implicated in the pathogenesis of sepsis and septic shock. This study was designed to examine the microRNA (miRNA) expression in whole blood from mice injected with intraperitoneal LPS.

Methods

C57BL/6 mice received intraperitoneal injections of varying concentrations (range, 10–1000 μg) of LPS from different bacteria, including Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, Salmonella enterica, and Serratia marcescens and were killed 2, 6, 24, and 72 h after LPS injection. Whole blood samples were obtained and tissues, including lung, brain, liver, and spleen, were harvested for miRNA expression analysis using an miRNA array (Phalanx miRNA OneArray® 1.0). Upregulated expression of miRNA targets in the whole blood of C57BL/6 and Tlr4^−/− mice injected with LPS was quantified using real-time RT-PCR and compared with that in the whole blood of C57BL/6 mice injected with lipoteichoic acid (LTA) from Staphylococcus aureus.

Results

Following LPS injection, a significant increase of 15 miRNAs was observed in the whole blood. Among them, only 3 miRNAs showed up-regulated expression in the lung, but no miRNAs showed a high expression level in the other examined tissues. Upregulated expression of the miRNA targets (let-7d, miR-15b, miR-16, miR-25, miR-92a, miR-103, miR-107 and miR-451) following LPS injection on real-time RT-PCR was dose- and time-dependent. miRNA induction occurred after 2 h and persisted for at least 6 h. Exposure to LPS from different bacteria did not induce significantly different expression of these miRNA targets. Additionally, significantly lower expression levels of let-7d, miR-25, miR-92a, miR-103, and miR-107 were observed in whole blood of Tlr4^−/− mice. In contrast, LTA exposure induced moderate expression of miR-451 but not of the other 7 miRNA targets.

Conclusions

We identified a specific whole blood–derived miRNA signature in mice exposed to LPS, but not to LTA, from different gram-negative bacteria. These whole blood-derived miRNAs are promising as biomarkers for LPS exposure.     

Human T-cell leukemia virus type I infects human lung epithelial cells and induces gene expression of cytokines, chemokines and cell adhesion molecules

Background

Cellular miRNAs play an important role in the regulation of gene expression in eukaryotes. Recently, miRNAs have also been shown to be able to target and inhibit viral gene expression. Computational predictions revealed earlier that the HIV-1 genome includes regions that may be potentially targeted by human miRNAs. Here we report the functionality of predicted miR-29a target site in the HIV-1 nef gene.

Results

We find that the human miRNAs hsa-miR-29a and 29b are expressed in human peripheral blood mononuclear cells. Expression of a luciferase reporter bearing the nef miR-29a target site was decreased compared to the luciferase construct without the target site. Locked nucleic acid modified anti-miRNAs targeted against hsa-miR-29a and 29b specifically reversed the inhibitory effect mediated by cellular miRNAs on the target site. Ectopic expression of the miRNA results in repression of the target Nef protein and reduction of virus levels.

Conclusion

Our results show that the cellular miRNA hsa-miR29a downregulates the expression of Nef protein and interferes with HIV-1 replication.     

MicroRNAs Show Mutually Exclusive Expression Patterns in the Brain of Adult Male Rats

Background

The brain is a major site of microRNA (miRNA) gene expression, but the spatial expression patterns of miRNAs within the brain have not yet been fully covered.

Methodology/Principal Findings

We have characterized the regional expression profiles of miRNAs in five distinct regions of the adult rat brain: amygdala, cerebellum, hippocampus, hypothalamus and substantia nigra. Microarray profiling uncovered 48 miRNAs displaying more than three-fold enrichment between two or more brain regions. Notably, we found reciprocal expression profiles for a subset of the miRNAs predominantly found (> ten times) in either the cerebellum (miR-206 and miR-497) or the forebrain regions (miR-132, miR-212, miR-221 and miR-222).

Conclusions/Significance

The results indicate that some miRNAs could be important for area-specific functions in the brain. Our data, combined with previous studies in mice, provides additional guidance for future investigations of miRNA functions in the brain.     

Coordinated aberrant expression of miRNAs in colon cancer

Applying the method of multiple parallel sequencing on the MiSeq platform (Illumina, United States), a comparative analysis of miRNA expression in tumor and normal colon tissue cells was performed. Forty miRNAs aberrantly expressed in cancer were detected. Among them, 15 and 25 miRNAs showed increased and decreased expression, respectively, for all or most of the cases. Sixteen miRNA clusters were identified, which showed a coordinated or incompletely coordinated aberrant expression in colorectal cancer cells. In two (miR-183/182 and miR-106b/25) and four (miR-143/145, miR-497/195, miR-30e/30c-1, and miR-30a/30c-2) miRNA clusters, respectively, a statistically significant coordinated increase or decrease in expression was registered for all miRNAs within the corresponding cluster. Three aberrantly expressed well-known miRNAs (miR-100-5p, miR-30d-5p, and miR-204-5p) were identified, which, however, had never before been associated with colorectal cancer. The obtained results demonstrate the potential and promising application of 6 miRNA clusters with coordinated aberrant expression as markers for colorectal cancer.     

An integrated approach of bioinformatic prediction and in vitro analysis identified that miR-34a targets <Emphasis Type="Italic">MET</Emphasis> and <Emphasis Type="Italic">AXL</Emphasis> in triple-negative breast cancer

Background

Breast cancer is the most prevalent cancer among women, and AXL and MET are the key genes in the PI3K/AKT/mTOR pathway as critical elements in proliferation and invasion of cancer cells. MicroRNAs (miRNAs) are small non-coding RNAs regulating the expression of genes.

Methods

Bioinformatic approaches were used to find a miRNA that simultaneously targets both AXL and MET 3′-UTRs. The expression of target miRNA was evaluated in triple-negative (MDA-MB-231) and HER2-overexpressing (SK-BR-3) breast cancer cell lines as well as normal breast cells, MCF-10A, using quantitative real-time PCR. Then, the miRNA was overexpressed in normal and cancer cell lines using a lentiviral vector system. Afterwards, effects of overexpressed miRNA on the expression of AXL and MET genes were evaluated using quantitative real-time PCR.

Results

By applying bioinformatic software and programs, miRNAs that target the 3′-UTR of both AXL and MET mRNAs were determined, and according to the scores, miR-34a was selected for further analyses. The expression level of miR-34a in MDA-MB-231 and SK-BR-3 was lower than that of MCF-10A. Furthermore, AXL and MET expression in SK-BR-3 and MDA-MB-231 was lower and higher, respectively, than that of MCF-10A. After miR-34a overexpression, MET and AXL were downregulated in MDA-MB-231. In addition, MET was downregulated in SK-BR-3, while AXL was upregulated in this cell line.

Conclusions

These findings may indicate that miR-34a is an oncogenic miRNA, downregulated in the distinct breast cancer subtypes. It also targets MET and AXL 3′-UTRs in triple-negative breast cancer. Therefore, it can be considered as a therapeutic target in this type of breast cancer.

     

Targeting of HER3 with Functional Cooperative miRNAs Enhances Therapeutic Activity in HER2-Overexpressing Breast Cancer Cells

Background

The HER3 receptor functions as a major cause of drug resistance in cancer treatment. It is believed that therapeutic targeting of HER3 is required to improve patient outcomes. It is not clear whether a novel strategy with two functional cooperative miRNAs would effectively inhibit erbB3 expression and potentiate the anti-proliferative/anti-survival effects of a HER2-targeted therapy (trastuzumab) and chemotherapy (paclitaxel) on HER2-overexpressing breast cancer cells.

Results

Combination of miR-125a and miR-205, as compared to either miRNA alone, potently inhibited expression of HER3 in HER2-overexpressing breast cancer BT474 cells. Co-expression of the two miRNAs not only reduced the levels of phosphorylated erbB3 (P-erbB3), Akt (P-Akt), and Src (P-Src), it also inhibited cell proliferation and increased cells at G1 phase. A multi-miRNA lentiviral vector - the cluster of miR-125a and miR-205 - was constructed to simultaneously express the two miRNAs in HER2-overexpressing breast cancer cells. Concurrent expression of miR-125a and miR-205 via the miRNA cluster transfection significantly enhanced trastuzumab-mediated growth inhibition and cell cycle G1 arrest in BT474 cells and markedly increased paclitaxel-induced apoptosis in another HER2-overexpressing breast cancer cell line HCC1954.

Conclusions

Here, we showed that functional cooperative miRNAs effectively suppressed erbB3 expression. This novel approach targeting of HER3 was able to enhance the therapeutic efficacy of trastuzumab and paclitaxel against HER2-overexpressing breast cancer.

     

The emerging role of microRNA-4487/6845-3p in Alzheimer’s disease pathologies is induced by Aβ25–35 triggered in SH-SY5Y cell

Background

Accumulation of amyloid β-peptide (Aβ) is implicated in the pathogenesis and development of Alzheimer’s disease (AD). Neuron-enriched miRNA was aberrantly regulated and may be associated with the pathogenesis of AD. However, regarding whether miRNA is involved in the accumulation of Aβ in AD, the underlying molecule mechanism remains unclear. Therefore, we conduct a systematic identification of the promising role of miRNAs in Aβ deposition, and shed light on the molecular mechanism of target miRNAs underlying SH-SY5Y cells treated with Aβ-induced cytotoxicity.

Results

Statistical analyses of microarray data revealed that 155 significantly upregulated and 50 significantly downregulated miRNAs were found on the basis of log2 | Fold Change |?≥?0.585 and P?< 0.05 filter condition through 2588 kinds of mature miRNA probe examined. PCR results show that the expression change trend of the selected six miRNAs (miR-6845-3p, miR-4487, miR-4534, miR-3622-3p, miR-1233-3p, miR-6760-5p) was consistent with the results of the gene chip. Notably, Aβ_25–35 downregulated hsa-miR-4487 and upregulated hsa-miR-6845-3p in SH-SY5Y cell lines associated with Aβ-mediated pathophysiology. Increase of hsa-miR-4487 could inhibit cells apoptosis, and diminution of hsa-miR-6845-3p could attenuate axon damage mediated by Aβ_25–35 in SH-SY5Y.

Conclusions

Together, these findings suggest that dysregulation of hsa-miR-4487 and hsa-miR-6845-3p contributed to the pathogenesis of AD associated with Aβ25–35 mediated by triggering cell apoptosis and synaptic dysfunction. It might be beneficial to understand the pathogenesis and development of clinical diagnosis and treatment of AD. Further, our well-designed validation studies will test the miRNAs signature as a prognostication tool associated with clinical outcomes in AD.