MicroRNA-199b Deregulation Shows Oncogenic Properties and Promising Clinical Value as Circulating Marker in Locally Advanced Rectal Cancer Patients

The identification of robust prognostic markers still represents a need in locally advanced rectal cancer (LARC). MicroRNAs (miRs) have progressively emerged as promising circulating markers, overcoming some limitations that traditional biopsy comprises. Tissue miR-199b deregulation has been reported to predict outcome and response to neoadjuvant chemoradiotherapy (nCRT) in LARC, and was also found to be associated with disease progression in colorectal cancer. However, its biological and clinical relevance remains to be fully clarified. Thus, we observed here that miR-199b regulates cell migration, aggressiveness, and cell growth, and inhibits colonosphere formation and induces caspase-dependent apoptosis. Moreover, miR-199b expression was quantified by real-time PCR in plasma samples from LARC patients and its downregulation was observed in 22.7% of cases. This alteration was found to be associated with higher tumor size (p = 0.002) and pathological stage (p = 0.020) after nCRT. Notably, we observed substantially lower global miR-199b expression associated with patient downstaging (p = 0.009), as well as in non-responders compared to those cases who responded to nCRT in both pre- (p = 0.003) and post-treatment samples (p = 0.038). In concordance, we found that miR-199b served as a predictor marker of response to neoadjuvant therapy in our cohort (p = 0.011). Altogether, our findings here demonstrate the functional relevance of miR-199b in this disease and its potential value as a novel circulating marker in LARC.     

Identification of the Regulatory Targets of miR-3687 and miR-4417 in Prostate Cancer Cells Using a Proteomics Approach

MicroRNAs (miRNA) are ubiquitous non-coding RNAs that have a prominent role in cellular regulation. The expression of many miRNAs is often found deregulated in prostate cancer (PCa) and castration-resistant prostate cancer (CRPC). Although their expression can be associated with PCa and CRPC, their functions and regulatory activity in cancer development are poorly understood. In this study, we used different proteomics tools to analyze the activity of hsa-miR-3687-3p (miR-3687) and hsa-miR-4417-3p (miR-4417), two miRNAs upregulated in CRPC. PCa and CRPC cell lines were transfected with miR-3687 or miR-4417 to overexpress the miRNAs. Cell lysates were analyzed using 2D gel electrophoresis and proteins were subsequently identified using mass spectrometry (Maldi-MS/MS). A whole cell lysate, without 2D-gel separation, was analyzed by ESI-MS/MS. The expression of deregulated proteins found across both methods was further investigated using Western blotting. Gene ontology and cellular process network analysis determined that miR-3687 and miR-4417 are involved in diverse regulatory mechanisms that support the CRPC phenotype, including metabolism and inflammation. Moreover, both miRNAs are associated with extracellular vesicles, which point toward a secretory mechanism. The tumor protein D52 isoform 1 (TD52-IF1), which regulates neuroendocrine trans-differentiation, was found to be substantially deregulated in androgen-insensitive cells by both miR-3687 and miR-4417. These findings show that these miRNAs potentially support the CRPC by truncating the TD52-IF1 expression after the onset of androgen resistance.     

Circulating Small EVs miRNAs as Predictors of Pathological Response to Neo-Adjuvant Therapy in Breast Cancer Patients

Neo-adjuvant therapy (NAT) is increasingly used in the clinic for the treatment of breast cancer (BC). Pathological response to NAT has been associated with improved patients’ survival; however, the current techniques employed for assessing the tumor response have significant limitations. Small EVs (sEVs)-encapsulated miRNAs have emerged as promising new biomarkers for diagnosis and prediction. Therefore, our study aims to explore the predictive value of these miRNAs for the pathological response to NAT in BC. By employing bioinformatic tools, we selected a set of miRNAs and evaluated their expression in plasma sEVs and BC biopsies. Twelve miRNAs were identified in sEVs, of which, miR-21-5p, 221-3p, 146a-5p and 26a-5p were significantly associated with the Miller–Payne (MP) pathological response to NAT. Moreover, miR-21-5p, 146a-5p, 26a-5p and miR-24-3p were independent as predictors of MP response to NAT. However, the expression of these miRNAs showed no correlation between sEVs and tissue samples, indicating that the mechanisms of miRNA sorting into sEVs still needs to be elucidated. Functional analysis of miRNA target genes and drug interactions revealed that candidate miRNAs and their targets, can be regulated by different NAT regimens. This evidence supports their role in governing the patients’ therapy response and highlights their potential use as prediction biomarkers.     

Concurrent Chemoradiotherapy-Driven Cell Plasticity by miR-200 Family Implicates the Therapeutic Response of Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is a common and fatal malignancy with an increasing incidence worldwide. Over the past decade, concurrent chemoradiotherapy (CCRT) with or without surgery is an emerging therapeutic approach for locally advanced ESCC. Unfortunately, many patients exhibit poor response or develop acquired resistance to CCRT. Once resistance occurs, the overall survival rate drops down rapidly and without proper further treatment options, poses a critical clinical challenge for ESCC therapy. Here, we utilized lab-created CCRT-resistant cells as a preclinical study model to investigate the association of chemoradioresistantresistance with miRNA-mediated cell plasticity alteration, and to determine whether reversing EMT status can re-sensitize refractory cancer cells to CCRT response. During the CCRT treatment course, refractory cancer cells adopted the conversion of epithelial to mesenchymal phenotype; additionally, miR-200 family members were found significantly down-regulated in CCRT resistance cells by miRNA microarray screening. Down-regulated miR-200 family in CCRT resistance cells suppressed E-cadherin expression through snail and slug, and accompany with an increase in N-cadherin. Rescuing expressions of miR-200 family members in CCRT resistance cells, particularly in miR-200b and miR-200c, could convert cells to epithelial phenotype by increasing E-cadherin expression and sensitize cells to CCRT treatment. Conversely, the suppression of miR-200b and miR-200c in ESCC cells attenuated E-cadherin, and that converted cells to mesenchymal type by elevating N-cadherin expression, and impaired cell sensitivity to CCRT treatment. Moreover, the results of ESCC specimens staining established the clinical relevance that higher N-cadherin expression levels associate with the poor CCRT response outcome in ESCC patients. Conclusively, miR-200b and miR-200c can modulate the conversion of epithelial–mesenchymal phenotype in ESCC, and thereby altering the response of cells to CCRT treatment. Targeting epithelial–mesenchymal conversion in acquired CCRT resistance may be a potential therapeutic option for ESCC patients.     

miRNAs Participate in the Regulation of Oxidative Stress-Related Gene Expression in Endometrioid Endometrial Cancer

Reactive oxygen species are formed as by-products of normal cell metabolism. They are needed to maintain cell homeostasis and signaling, which is possible due to defense systems. Disruption of this balance leads to oxidative stress that can induce cancer. Redox regulation by miRNAs may be a potential therapeutic target. The aim of the study was to assess the activity of genes associated with oxidative stress in endometrial cancer and to determine their relationship with miRNAs. The study included 45 patients with endometrioid endometrial cancer and 45 without neoplastic changes. The expression profile of genes associated with oxidative stress was determined with mRNA microarrays, RT-qPCR and ELISA. The miRNA prediction was performed based on the miRNA microarray experiment and the mirDB tool. PRDX2 and AQP1 showed overexpression that was probably not related to miRNA activity. A high level of PKD2 may be the result of a decrease in the activity of miR-195-3p, miR-20a, miR-134. A SOD3 level reduction can be caused by miR-328, miR-363. In addition, miR-363 can also regulate KLF2 expression. In the course of endometrial cancer, the phenomenon of oxidative stress is observed, the regulation of which may be influenced by miRNAs.     

The Tumor Suppressor Roles of miR-433 and miR-127 in Gastric Cancer

The discovery of microRNAs (miRNAs) provides a new and powerful tool for studying the mechanism, diagnosis and treatment of human cancers. Currently, the methylation epigenetic silencing of miRNAs with tumor suppressor features by CpG island hypermethylation is emerging as a common hallmark of different tumors. Here we showed that miR-433 and miR-127 were significantly down-regulated in gastric cancer (GC) tissues compared with the adjacent normal regions in 86 paired samples. Moreover, the lower level of miR-433 and miR-127 was associated with pM or pTNM stage in clinical gastric cancer patients. The restored expression of miR-433 and miR-127 in GC cells upon 5-Aza-CdR and TSA treatment suggested the loss of miR-433 and miR-127 was at least partly regulated by epigenetic modification in GC. Furthermore, the ectopic expression of miR-433 and miR-127 in gastric cancer cell lines HGC-27 inhibits cell proliferation, cell cycle progression, cell migration and invasion by directly interacting with the mRNA encoding oncogenic factors KRAS and MAPK4 respectively. Taken together, our results showed that miR-433 and miR-127 might act as tumor suppressors in GC, and it may provide novel diagnostic and therapeutic options for human GC clinical operation in the near future.     

miRNA-Mediated Epigenetic Regulation of Treatment Response in RA Patients—A Systematic Review

This study aimed to evaluate the role of microRNAs (miRNA) as biomarkers of treatment response in rheumatoid arthritis (RA) patients through a systematic review of the literature. The MEDLINE and Embase databases were searched for studies including RA-diagnosed patients treated with disease-modifying antirheumatic drugs (DMARDs) that identify miRNAs as response predictors. Review inclusion criteria were met by 10 studies. The main outcome of the study was the response to treatment, defined according to EULAR criteria. A total of 839 RA patients and 67 healthy donors were included in the selected studies. RA patients presented seropositivity for the rheumatoid factor of 74.7% and anti-citrullinated C-peptide antibodies of 63.6%. After revision, 15 miRNAs were described as treatment response biomarkers for methotrexate, anti-tumour necrosis factor (TNF), and rituximab. Among treatments, methotrexate presented the highest number of predictor miRNAs: miR-16, miR-22, miR-132, miR-146a and miR-155. The most polyvalent miRNAs were miR-146a, predicting response to methotrexate and anti-TNF, and miR-125b, which predicts response to infliximab and rituximab. Our data support the role of miRNAs as biomarkers of treatment response in RA and point to DMARDs modifying the miRNAs expression. Nevertheless, further studies are needed since a meta-analysis that allows definitive conclusions is not possible due to the lack of studies in this field.     

Integrated Genomics Identifies miR-181/TFAM Pathway as a Critical Driver of Drug Resistance in Melanoma

MicroRNAs (miRNAs) are attractive therapeutic targets and promising candidates as molecular biomarkers for various therapy-resistant tumors. However, the association between miRNAs and drug resistance in melanoma remains to be elucidated. We used an integrative genomic analysis to comprehensively study the miRNA expression profiles of drug-resistant melanoma patients and cell lines. MicroRNA-181a and -181b (miR181a/b) were identified as the most significantly down-regulated miRNAs in resistant melanoma patients and cell lines. Re-establishment of miR-181a/b expression reverses the resistance of melanoma cells to the BRAF inhibitor dabrafenib. Introduction of miR-181 mimics markedly decreases the expression of TFAM in A375 melanoma cells resistant to BRAF inhibitors. Furthermore, melanoma growth was inhibited in A375 and M14 resistant melanoma cells transfected with miR-181a/b mimics, while miR-181a/b depletion enhanced resistance in sensitive cell lines. Collectively, our study demonstrated that miR-181a/b could reverse the resistance to BRAF inhibitors in dabrafenib resistant melanoma cell lines. In addition, miR-181a and -181b are strongly down-regulated in tumor samples from patients before and after the development of resistance to targeted therapies. Finally, melanoma tissues with high miR-181a and -181b expression presented favorable outcomes in terms of Progression Free Survival, suggesting that miR-181 is a clinically relevant candidate for therapeutic development or biomarker-based therapy selection.     

Extracellular Disposal of Tumor-Suppressor miRs-145 and -34a via Microvesicles and 5-FU Resistance of Human Colon Cancer Cells

The dysregulation of microRNA (miRNA) expression causes various kinds of diseases. Especially, alterations in miRNA expression levels are frequently observed in human tumor cells and are associated with cancer pathogenesis. Earlier we established Fluorouracil (5-FU)-resistant human colon cancer DLD-1 cells (DLD-1/5FU) from parental 5-FU- sensitive DLD-1 cells. In the present study, we examined the expression of miRNA in each cell line and in its extracellular microvesicles (MVs) before and after treatment with 5-FU. The nascent RNAs of anti-oncogenic miR-34a and -145 labeled with EU in both cells were proved to be transferred into MVs in both cell lines. The levels of miR-34a and -145 in the cells and in their MVs were not largely different in the two cell lines, and a substantial amount of both miRNAs was secreted by both cell lines even in the steady-state condition. The exposure of both cell lines to 5-FU significantly increased the intracellular levels of miR-145 and miR-34a in the 5-FU-sensitive DLD-1 cells, whereas the level of neither miR was elevated in the DLD-1/5FU cells. Interestingly, the amount of miR-145 detected in the small MVs shed into the medium of the parental cells was reduced after the treatment with 5-FU. On the other hand, the intracellular expression of miR-34a in the DLD-1/5FU cells was down-regulated compared with that in the parental DLD-1 cells even in the steady-state condition. As to the miR-34a secreted into MVs, the increase in the level in DLD-1/5FU cells was greater than that in the parental DLD-1 cells after the treatment with 5-FU. Thus, the intra- and extracellular miR-145 and -34a were closely associated with 5-FU resistance, and the resistance was in part due to the enhanced secretion of miR-145 and -34a via MVs, resulting in low intracellular levels of both miRNAs.     

miR-451靶向调控肾小球系膜细胞Ywhaz基因的表达

目的探讨miR-451对肾小球系膜细胞Ywhaz基因表达的靶向调控。方法应用生物信息学技术对miR-451的靶基因进行预测,PCR法扩增靶基因3′UTR全长片段,插入荧光素酶报告载体pmiR-RB-REPORTTMvector中,构建荧光素酶报告质粒pmiR-Ywhaz-3′UTR。将miR-451 mimics和NC mimics分别转染高糖培养条件下的小鼠系膜细胞,将miR-451 inhibitor和NC inhibitor分别转染低糖培养条件下的小鼠系膜细胞,采用Real-time RT-PCR和Westernblot法检测miR-451和Ywhaz的表达水平;将miR-451 mimics和NC mimics分别与pmiR-Ywhaz-3′UTR共转染高糖培养条件下的小鼠系膜细胞,miR-451 inhibitor和NC inhibitor分别与pmiR-Ywhaz-3′UTR共转染低糖培养条件下的小鼠系膜细胞,检测各组细胞荧光素酶活性。结果 Ywhaz基因3′UTR区有11个碱基与miR-451种子序列匹配,其中7个碱基呈高度保守性;荧光素酶报告质粒经测序鉴定构建正确;miR-451在miR-451 mimics组呈高表达,在miR-451 inhibitor组表达降低;miR-451可抑制Ywhaz的蛋白表达;荧光素酶活性检测发现,miR-451可通过与Ywhaz3′UTR的结合,抑制Ywhaz的表达。结论 miR-451可直接靶向糖尿病相关基因Ywhaz,抑制其蛋白表达,为进一步研究miR-451调控早期糖尿病肾病发生发展的机制提供了依据。     

The Relationship and Expression of miR-451a,miR-25-3p and PTEN in Early Peritoneal Endometriotic Lesions and Their Modulation In Vitro

Background: miR-451a can function as a tumor suppresser and has been shown to be elevated in both endometriotic lesion tissue and serum from women with endometriosis. To further explore the role of miR-451a in the pathophysiology of endometriosis, specifically, further evaluating its association with the tumor suppressor, phosphatase and tensin homolog (PTEN), we examined their expression in individual endometriotic lesion tissue to gain insight into their relationship and further explore if miR-451a regulates PTEN expression. Methods: A total of 55 red, peritoneal endometriotic lesions and matched eutopic endometrial specimens were obtained from 46 patients with endometriosis. miR-451a, miR-25-3p and PTEN mRNA levels were assessed by qRT-PCR and reported for each matched eutopic and ectopic sample. To evaluate miR-451a and miR-25-3p expression of miR-25-3p and PTEN, respectively, 12Z cells (endometriotic epithelial cell line) were transfected and miR-25-3p expression was assessed by qRT-PCR, while PTEN protein expression was assessed by Western blotting. Results: PTEN and miR-25-3p expression exhibited an inverse relationship, as did miR-25-3p and miR-451a in individual lesions. Over-expression of miR-451a in 12Z cells resulted in down-regulation of miR-25-3p, while up-regulation of miR-25-3p resulted in down-regulation of PTEN protein expression. Conclusions: By assessing individual endometriotic lesion expression, we discovered an inverse relationship between miR-451a, miR-25-3p and PTEN, while in vitro cell transfection studies suggest that miR-451a may regulate PTEN expression via modulating miR-25-3p.     

Downregulation of miR-506-3p Facilitates EGFR-TKI Resistance through Induction of Sonic Hedgehog Signaling in Non-Small-Cell Lung Cancer Cell Lines

Non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation eventually develop resistance to EGFR-targeted tyrosine kinase inhibitors (TKIs). Treatment resistance remains the primary obstacle to the successful treatment of NSCLC. Although drug resistance mechanisms have been studied extensively in NSCLC, the regulation of these mechanisms has not been completely understood. Recently, increasing numbers of microRNAs (miRNAs) are implicated in EGFR-TKI resistance, indicating that miRNAs may serve as novel targets and may hold promise as predictive biomarkers for anti-EGFR therapy. MicroRNA-506 (miR-506) has been identified as a tumor suppressor in many cancers, including lung cancer; however, the role of miR-506 in lung cancer chemoresistance has not yet been addressed. Here we report that miR-506-3p expression was markedly reduced in erlotinib-resistant (ER) cells. We identified Sonic Hedgehog (SHH) as a novel target of miR-506-3p, aberrantly activated in ER cells. The ectopic overexpression of miR-506-3p in ER cells downregulates SHH signaling, increases E-cadherin expression, and inhibits the expression of vimentin, thus counteracting the epithelial–mesenchymal transition (EMT)-mediated chemoresistance. Our results advanced our understanding of the molecular mechanisms underlying EGFR-TKI resistance and indicated that the miR-506/SHH axis might represent a novel therapeutic target for future EGFR mutated lung cancer treatment.     

MicroRNAs in Leukemias: A Clinically Annotated Compendium

Leukemias are a group of malignancies of the blood and bone marrow. Multiple types of leukemia are known, however reliable treatments have not been developed for most leukemia types. Furthermore, even relatively reliable treatments can result in relapses. MicroRNAs (miRNAs) are a class of short, noncoding RNAs responsible for epigenetic regulation of gene expression and have been proposed as a source of potential novel therapeutic targets for leukemias. In order to identify central miRNAs for leukemia, we conducted data synthesis using two databases: miRTarBase and DISNOR. A total of 137 unique miRNAs associated with 16 types of leukemia were retrieved from miRTarBase and 86 protein-coding genes associated with leukemia were retrieved from the DISNOR database. Based on these data, we formed a visual network of 248 miRNA-target interactions (MTI) between leukemia-associated genes and miRNAs associated with ≥4 leukemia types. We then manually reviewed the literature describing these 248 MTIs for interactions identified in leukemia studies. This manually curated data was then used to visualize a network of 64 MTIs identified in leukemia patients, cell lines and animal models. We also formed a visual network of miRNA-leukemia associations. Finally, we compiled leukemia clinical trials from the ClinicalTrials database. miRNAs with the highest number of MTIs were miR-125b-5p, miR-155-5p, miR-181a-5p and miR-19a-3p, while target genes with the highest number of MTIs were TP53, BCL2, KIT, ATM, RUNX1 and ABL1. The analysis of 248 MTIs revealed a large, highly interconnected network. Additionally, a large MTI subnetwork was present in the network visualized from manually reviewed data. The interconnectedness of the MTI subnetwork suggests that certain miRNAs represent central disease molecules for multiple leukemia types. Additional studies on miRNAs, their target genes and associated biological pathways are required to elucidate the therapeutic potential of miRNAs in leukemia.     

MiR-25 Protects Cardiomyocytes against Oxidative Damage by Targeting the Mitochondrial Calcium Uniporter

MicroRNAs (miRNAs) are a class of small non-coding RNAs, whose expression levels vary in different cell types and tissues. Emerging evidence indicates that tissue-specific and -enriched miRNAs are closely associated with cellular development and stress responses in their tissues. MiR-25 has been documented to be abundant in cardiomyocytes, but its function in the heart remains unknown. Here, we report that miR-25 can protect cardiomyocytes against oxidative damage by down-regulating mitochondrial calcium uniporter (MCU). MiR-25 was markedly elevated in response to oxidative stimulation in cardiomyocytes. Further overexpression of miR-25 protected cardiomyocytes against oxidative damage by inactivating the mitochondrial apoptosis pathway. MCU was identified as a potential target of miR-25 by bioinformatical analysis. MCU mRNA level was reversely correlated with miR-25 under the exposure of H₂O₂, and MCU protein level was largely decreased by miR-25 overexpression. The luciferase reporter assay confirmed that miR-25 bound directly to the 3'' untranslated region (UTR) of MCU mRNA. MiR-25 significantly decreased H₂O₂-induced elevation of mitochondrial Ca²⁺ concentration, which is likely to be the result of decreased activity of MCU. We conclude that miR-25 targets MCU to protect cardiomyocytes against oxidative damages. This finding provides novel insights into the involvement of miRNAs in oxidative stress in cardiomyocytes.     

MicroRNA Expression Profile in TSC Cell Lines and the Impact of mTOR Inhibitor

The aim of this study was to assess the potential implication of microRNA on tuberous sclerosis (TSC) pathogenesis by performing microRNA profiling on cell lines silencing TSC1 or TSC2 genes using qPCR panels, before and after incubation with rapamycin. Significant differences in expression were observed between samples before and after rapamycin treatment in nineteen miRNAs in TSC1, five miRNAs in TSC2 and seven miRNAs in controls. Of miRNAs dysregulated before rapamycin treatment, three normalized after treatment in the TSC1 group (miR-21-3p, miR-433-3p, let-7g-3p) and one normalized in the TSC2 group (miR-1224-3p). Of the miRNAs dysregulated before rapamycin treatment in the TSC1 and TSC2 groups, two did not normalize after treatment (miR-33a-3p, miR-29a-3p). The results of the possible targets indicated that there are four common genes with seed regions susceptible to regulation by those miRNAs: ZBTB20, PHACTR2, PLXNC1 and ATP1B4. Our data show no changes in mRNA expression of these targets after rapamycin treatment. In conclusion, results of our study indicate the involvement of miRNA dysregulation in the pathogenesis of TSC. Some of the miRNA might be used as markers of treatment efficacy and autonomic miRNA as a target for future therapy.     

Integrative Analyses of Circulating Small RNAs and Kidney Graft Transcriptome in Transplant Glomerulopathy

Transplant glomerulopathy develops through multiple mechanisms, including donor-specific antibodies, T cells and innate immunity. This study investigates circulating small RNA profiles in serum samples of kidney transplant recipients with biopsy-proven transplant glomerulopathy. Among total small RNA population, miRNAs were the most abundant species in the serum of kidney transplant patients. In addition, fragments arising from mature tRNA and rRNA were detected. Most of the tRNA fragments were generated from 5′ ends of mature tRNA and mainly from two parental tRNAs: tRNA-Gly and tRNA-Glu. Moreover, transplant patients with transplant glomerulopathy displayed a novel tRNA fragments signature. Gene expression analysis from allograft tissues demonstrated changes in canonical pathways related to immune activation such as iCos-iCosL signaling pathway in T helper cells, Th1 and Th2 activation pathway, and dendritic cell maturation. mRNA targets of down-regulated miRNAs such as miR-1224-5p, miR-4508, miR-320, miR-378a from serum were globally upregulated in tissue. Integration of serum miRNA profiles with tissue gene expression showed that changes in serum miRNAs support the role of T-cell mediated mechanisms in ongoing allograft injury.     

Oxidative Stress Mediated-Alterations of the MicroRNA Expression Profile in Mouse Hippocampal Neurons

Oxidative stress plays a critical role in the etiology and pathogenesis of neurodegenerative disorders, and the molecular mechanisms that control the neuron response to ROS have been extensively studied. However, the oxidative stress-effect on miRNA expression in hippocampal neurons has not been investigated, and little is known on the effect of ROS-modulated miRNAs on cell function. In this study, H₂O₂ was used to stimulate the mouse primary hippocampal neurons to develop an oxidative stress cell model. The alterations of miRNAs expression were detected by microarray analysis and five miRNAs were validated by real-time RT-PCR. The bioinformatic analysis of deregulated miRNAs was performed to determine their potential roles in the pathogenesis of neurological disorders. We found that H₂O₂ mediated a total of 101 deregulated miRNAs, which mainly took part in the regulation of the MAPK pathway. Among them, miR-135b and miR-708 were up-regulated significantly and their targets were predicted to be involved in DNA recombination, protein ubiquitination, protein autophosphorylation and development of neurons. These results demonstrated that oxidative stress alters the miRNA expression profile of hippocampal neurons, and the deregulated miRNAs might play a potential role in the pathogenesis of neurodegenerative diseases, such as Alzheimer’s disease (AD).