GCH1-regulated miRNAs are potential targets for microglial activation in neuropathic pain

Neuropathic pain (NP) is a chronic pain directly caused by injury or disease of the somatosensory nervous system. Previous studies suggest that GTP cyclohydrolase I (GCH1) may play a pivotal role in microglial activation, which has been shown to be essential for NP. However, its underlying mechanisms in microglial activation remain unclear. A wide range of microRNAs (miRNAs) have been found to be involved in microglial activation-induced NP. To identify the miRNAs regulated by GCH1 and predict their functions in the progression of microglial activation, we analyzed the miRNA expression profiles of GCH1-knockdown (KD) BV2 microglial cells. Small RNA-sequencing analysis revealed 13 differentially expressed (DE) miRNAs in GCH1-KD cells. The target genes of DE miRNAs mainly participate in PI3K-Akt signaling pathway, peroxisome and ferroptosis. The miRNA–mRNA regulatory network analysis showed that GCH1, MAP4K5 and YWHAB acted as hub genes. qRT-PCR results further verified the expression levels of mmu-miR-1a-3p, mmu-miR-133a-3p, mmu-miR-7a-5p and mmu-miR-10a-5p in GCH1-KD cells, which were consistent with the sequencing data. In addition, our data indicated that overexpression of mmu-miR-133a-3p alleviated the pro-inflammatory cytokines IL-1β and IL-6 production induced by lipopolysaccharide (LPS), indicating that mmu-miR-133a-3p has a negative effect on microglial activation. Taken together, our findings suggest that many miRNAs regulated by GCH1 may be involved in microglial activation, which may provide new potential targets for GCH1 in the pathogenesis of NP.     

Identification of the microRNA Expression Profile in the Regenerative Neonatal Mouse Heart by Deep Sequencing

MicroRNAs (miRNAs) are small noncoding RNAs that are involved in key biological processes, including development, differentiation, and regeneration. The global miRNA expression profile that regulates the regenerative potential of the neonatal mouse heart has not been reported. We performed deep sequencing to determine the genome-wide miRNA expression profile of the neonatal mouse heart at three key ages (1, 6, and 7 days). The miRNAs at least 1.4-fold differentially expressed between the three time points were selected for further analysis. Two miRNAs (mmu-miR-22-5p and mmu-miR-338-3p) were significantly upregulated, and nine miRNAs (mmu-miR-324-5p, mmu-miR-337-5p, mmu-miR-339-5p, mmu-miR-365-1-5p, mmu-miR-500-3p, mmu-miR-505-5p, mmu-miR-542-5p, mmu-miR-668-3p, and mmu-miR-92a-1-5p) were significantly downregulated in cardiac tissue of 7-day-old mice compared to 1- and 6-day-old mice. The expression patterns of five significantly different miRNAs were verified by quantitative real-time PCR. Furthermore, the potential targets of these putative miRNAs were suggested using miRNA target prediction tools. The candidate target genes are involved in the myocardial regenerative process, with a prominent role for the Notch signaling pathway. Our study provides a valuable resource for future investigation of the biological function of miRNAs in heart regeneration.     

Weight-reduction through a low-fat diet causes differential expression of circulating microRNAs in obese C57BL/6 mice

Background

To examine the circulating microRNA (miRNA) expression profile in a mouse model of diet-induced obesity (DIO) with subsequent weight reduction achieved via low-fat diet (LFD) feeding.

Results

Eighteen C57BL/6NCrl male mice were divided into three subgroups: (1) control, mice were fed a standard AIN-76A (fat: 11.5 kcal %) diet for 12 weeks; (2) DIO, mice were fed a 58 kcal % high-fat diet (HFD) for 12 weeks; and (3) DIO + LFD, mice were fed a HFD for 8 weeks to induce obesity and then switched to a 10.5 kcal % LFD for 4 weeks. A switch to LFD feeding led to decreases in body weight, adiposity, and blood glucose levels in DIO mice. Microarray analysis of miRNA using The Mouse & Rat miRNA OneArray® v4 system revealed significant alterations in the expression of miRNAs in DIO and DIO + LFD mice. Notably, 23 circulating miRNAs (mmu-miR-16, mmu-let-7i, mmu-miR-26a, mmu-miR-17, mmu-miR-107, mmu-miR-195, mmu-miR-20a, mmu-miR-25, mmu-miR-15b, mmu-miR-15a, mmu-let-7b, mmu-let-7a, mmu-let-7c, mmu-miR-103, mmu-let-7f, mmu-miR-106a, mmu-miR-106b, mmu-miR-93, mmu-miR-23b, mmu-miR-21, mmu-miR-30b, mmu-miR-221, and mmu-miR-19b) were significantly downregulated in DIO mice but upregulated in DIO + LFD mice. Target prediction and function annotation of associated genes revealed that these genes were predominantly involved in metabolic, insulin signaling, and adipocytokine signaling pathways that directly link the pathophysiological changes associated with obesity and weight reduction.

Conclusions

These results imply that obesity-related reductions in the expression of circulating miRNAs could be reversed through changes in metabolism associated with weight reduction achieved through LFD feeding.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1896-3) contains supplementary material, which is available to authorized users.     

Genome-wide microRNA screening reveals miR-582-5p as a mesenchymal stem cell-specific microRNA in subchondral bone of the human knee joint

Emerging evidence suggests that microRNAs (miRNAs) may be pathologically involved in osteoarthritis (OA). Subchondral bone (SCB) sclerosis is accounted for the knee osteoarthritis (KOA) development and progression. In this study, we aimed to screen the miRNA biomarkers of KOA and investigated whether these miRNAs regulate the differentiation potential of mesenchymal stem cells (MSCs) and thus contributing to SCB. We identified 48 miRNAs in the blood samples in KOA patients (n = 5) through microarray expression profiling detection. After validation with larger sample number, we confirmed hsa-miR-582-5p and hsa-miR-424-5p were associated with the pathology of SCB sclerosis. Target genes prediction and pathway analysis were implemented with online databases, indicating these two candidate miRNAs were closely related to the pathways of pluripotency of stem cells and pathology of OA. Surprisingly, mmu-miR-582-5p (homology of hsa-miR-582-5p) was downregulated in osteogenic differentiation and upregulated in adipogenic differentiation of mesenchymal progenitor C3H10T1/2 cells, whereas mmu-mir-322-5p (homology of hsa-miR-424-5p) showed no change through the in vitro study. Supplementing mmu-miR-582-5p mimics blocked osteogenic and induced adipogenic differentiation of C3H10T1/2 cells, whereas silencing of the endogenous mmu-miR-582-5p enhanced osteogenic and repressed adipogenic differentiation. Further mechanism studies showed that mmu-miR-582-5p was directly targeted to Runx2. Mutation of putative mmu-miR-582-5p binding sites in Runx2 3′ untranslated region (3′UTR) could abolish the response of the 3′UTR-luciferase construct to mmu-miR-582-5p supplementation. Generally speaking, our data suggest that miR-582-5p is an important biomarker of KOA and is able to regulate osteogenic and adipogenic differentiation of MSCs via targeting Runx2. The study also suggests that miR-582-5p may play a crucial role in SCB sclerosis of human KOA.     

Differential expression of microRNAs in adipose tissue after long-term high-fat diet-induced obesity in mice

Obesity is a major health concern worldwide which is associated with increased risk of chronic diseases such as metabolic syndrome, cardiovascular disease and cancer. The elucidation of the molecular mechanisms involved in adipogenesis and obesogenesis is of essential importance as it could lead to the identification of novel biomarkers and therapeutic targets for the development of anti-obesity drugs. MicroRNAs (miRNAs) have been shown to play regulatory roles in several biological processes. They have become a growing research field and consist of promising pharmaceutical targets in various fields such as cancer, metabolism, etc. The present study investigated the possible implication of miRNAs in adipose tissue during the development of obesity using as a model the C57BLJ6 mice fed a high-fat diet.C57BLJ6 wild type male mice were fed either a standard (SD) or a high-fat diet (HFD) for 5 months. Total RNA was prepared from white adipose tissue and was used for microRNA profiling and qPCR.Twenty-two of the most differentially expressed miRNAs, as identified by the microRNA profiling were validated using qPCR. The results of the present study confirmed previous results. The up-regulation of mmu-miR-222 and the down-regulation of mmu-miR-200b, mmu-miR-200c, mmu-miR-204, mmu-miR-30a*, mmu-miR-193, mmu-miR-378 and mmu-miR-30e* after HFD feeding has also been previously reported. On the other hand, we show for the first time the up-regulation of mmu-miR-342-3p, mmu-miR-142-3p, mmu-miR-142-5p, mmu-miR-21, mmu-miR-146a, mmu-miR-146b, mmu-miR-379 and the down-regulation of mmu-miR-122, mmu-miR-133b, mmu-miR-1, mmu-miR-30a*, mmu-miR-192 and mmu-miR-203 during the development of obesity. However, future studies are warranted in order to understand the exact role that miRNAs play in adipogenesis and obesity.     

Circulating miR-23b-3p,miR-145-5p and miR-200b-3p are potential biomarkers to monitor acute pain associated with laminitis in horses

Circulating microRNAs (miRNAs) are emerging as promising biomarkers for several disorders and related pain. In equine practice, acute laminitis is a common disease characterised by intense pain that severely compromises horse welfare. Recently, the Horse Grimace Scale (HGS), a facial expression-based pain coding system, was shown to be a valid welfare indicator to identify pain linked to acute laminitis. The present study aimed to: determine whether miRNAs can be used as biomarkers for acute pain in horses (Equus caballus) affected by laminitis; integrate miRNAs to their target genes and to categorise target genes for biological processes; gather additional evidence on concurrent validity of HGS by investigating how it correlates to miRNAs. Nine horses presenting acute laminitis with no prior treatment were recruited. As control group, nine healthy horses were further included in the experimental design. Samples were collected from horses with laminitis at admission before any treatment (‘pre-treatment’) and 7 days after routine laminitis treatment (‘post-treatment’). The expression levels of nine circulating miRNAs, namely hsa-miR-532-3p, hsa-miR-219-5p, mmu-miR-134-5p, mmu-miR-124a-3p, hsa-miR-200b-3p, hsa-miR-146a-5p, hsa-miR-23b-3p, hsa-miR-145-5p and hsa-miR-181a-5p, were detected and assessed as potential biomarkers of pain by quantitative PCR using TaqMan® probes. The area under the receiver operating curve (AUC) was then used to evaluate the diagnostic performance of miRNAs. Molecular data were integrated with HGS scores assessed by one trained treatment and time point blind veterinarian. The comparative analysis demonstrated that the levels of miR-23b-3p (P=0.029), miR-145-5p (P=0.015) and miR-200b-3p (P=0.023) were significantly higher in pre-treatment and the AUCs were 0.854, 0.859 and 0.841, respectively. MiR-200b-3p decreased after routine laminitis treatment (P=0.043). Combining two miRNAs in a panel, namely miR-145-5p and miR-200b-3p, increased efficiency in distinguishing animals with acute pain from controls. In addition, deregulated miRNAs were positively correlated to HGS scores. Computational target prediction and functional enrichment identified common biological pathways between different miRNAs. In particular, the glutamatergic pathway was affected by all three miRNAs, suggesting a crucial role in the pathogenesis of pain. In conclusion, the dynamic expression of circulating miR-23b-3p, miR-145-5p and miR-200b-3p was detected in horses with acute laminitis and miRNAs can be considered potentially promising pain biomarkers. Further studies are needed in order to assess their relevancy in other painful conditions severely compromising horse welfare. An important implication would be the possibility to use them for the concurrent validation of non-invasive indicators of pain in horses.     

XB130, a New Adaptor Protein,Regulates Expression of Tumor Suppressive MicroRNAs in Cancer Cells

XB130, a novel adaptor protein, promotes cell growth by controlling expression of many related genes. MicroRNAs (miRNAs), which are frequently mis-expressed in cancer cells, regulate expression of targeted genes. In this present study, we aimed to explore the oncogenic mechanism of XB130 through miRNAs regulation. We analyzed miRNA expression in XB130 short hairpin RNA (shRNA) stably transfected WRO thyroid cancer cells by a miRNA array assay, and 16 miRNAs were up-regulated and 22 miRNAs were down-regulated significantly in these cells, in comparison with non-transfected or negative control shRNA transfected cells. We chose three of the up-regulated miRNAs (miR-33a, miR-149 and miR-193a-3p) and validated them by real-time qRT-PCR. Ectopic overexpression of XB130 suppressed these 3 miRNAs in MRO cells, a cell line with very low expression of XB130. Furthermore, we transfected miR mimics of these 3 miRNAs into WRO cells. They negatively regulated expression of oncogenes (miR-33a: MYC, miR-149: FOSL1, miR-193a-3p: SLC7A5), by targeting their 3′ untranslated region, and reduced cell growth. Our results suggest that XB130 could promote growth of cancer cells by regulating expression of tumor suppressive miRNAs and their targeted genes.     

Curcumin Intake Affects miRNA Signature in Murine Melanoma with mmu-miR-205-5p Most Significantly Altered

Melanoma is the most aggressive form of skin cancer with estimated 48,000 deaths per year worldwide. The polyphenol curcumin derived from the plant Curcuma longa is well known for its anti-inflammatory and anti-cancerogenic properties. Accordingly, dietary intake of this compound may be suitable for melanoma prevention. However, how this compound affects basic cellular mechanisms in developing melanoma still remains elusive. Therefore, the aim of this study was to investigate for the first time the impact of oral curcumin administration on the miRNA signature of engrafting melanoma. For this purpose, the effects of a 4% curcumin diet were tested on melanoma, which were established by injection of murine B78H1 cells in the flank of C57BL/6 mice. Curcumin diet or standard chow (control) was administered two weeks prior to injection of tumor cells until termination of the experiment. High throughput chip-based array analysis was deployed to detect alterations in the miRNA signature of the tumors. Curcumin treatment significantly reduced the growth of the flank tumors. Furthermore the miRNA expression signature in tumors was substantially altered by curcumin intake with mmu-miR-205-5p over 100 times higher expressed when compared to controls. The expression levels of identified key miRNAs in the tumor samples were confirmed by quantitative real-time polymerase chain reaction (qRT-PCR). A comparable expression pattern of these miRNAs was also detected in other curcumin-treated melanoma cell lines under in vitro conditions. Putative targets of curcumin-induced up-regulated miRNAs were enriched in ‘o-glycan biosynthesis’, ‘endoplasmatic reticulum protein processing’ and different cancer-related pathways. Western Blot analyses revealed that of these targets anti-apoptotic B-cell CLL/lymphoma 2 (Bcl-2) and proliferating cell nuclear antigen (PCNA) were significantly down-regulated in curcumin-treated tumors. These findings demonstrate a profound alteration of the miRNA expression signature in engrafting curcumin-treated melanoma with mmu-miR-205-5p being up-regulated most significantly.     

A Viral microRNA Down-Regulates Multiple Cell Cycle Genes through mRNA 5′UTRs

Global gene expression data combined with bioinformatic analysis provides strong evidence that mammalian miRNAs mediate repression of gene expression primarily through binding sites within the 3′ untranslated region (UTR). Using RNA induced silencing complex immunoprecipitation (RISC-IP) techniques we have identified multiple cellular targets for a human cytomegalovirus (HCMV) miRNA, miR-US25-1. Strikingly, this miRNA binds target sites primarily within 5′UTRs, mediating significant reduction in gene expression. Intriguingly, many of the genes targeted by miR-US25-1 are associated with cell cycle control, including cyclin E2, BRCC3, EID1, MAPRE2, and CD147, suggesting that miR-US25-1 is targeting genes within a related pathway. Deletion of miR-US25-1 from HCMV results in over expression of cyclin E2 in the context of viral infection. Our studies demonstrate that a viral miRNA mediates translational repression of multiple cellular genes by targeting mRNA 5′UTRs.     

MicroRNAs profiling in murine models of acute and chronic asthma: a relationship with mRNAs targets

Background

miRNAs are now recognized as key regulator elements in gene expression. Although they have been associated with a number of human diseases, their implication in acute and chronic asthma and their association with lung remodelling have never been thoroughly investigated.

Methodology/Principal Findings

In order to establish a miRNAs expression profile in lung tissue, mice were sensitized and challenged with ovalbumin mimicking acute, intermediate and chronic human asthma. Levels of lung miRNAs were profiled by microarray and in silico analyses were performed to identify potential mRNA targets and to point out signalling pathways and biological processes regulated by miRNA-dependent mechanisms. Fifty-eight, 66 and 75 miRNAs were found to be significantly modulated at short-, intermediate- and long-term challenge, respectively. Inverse correlation with the expression of potential mRNA targets identified mmu-miR-146b, -223, -29b, -29c, -483, -574-5p, -672 and -690 as the best candidates for an active implication in asthma pathogenesis. A functional validation assay was performed by cotransfecting in human lung fibroblasts (WI26) synthetic miRNAs and engineered expression constructs containing the coding sequence of luciferase upstream of the 3′UTR of various potential mRNA targets. The bioinformatics analysis identified miRNA-linked regulation of several signalling pathways, as matrix metalloproteinases, inflammatory response and TGF-β signalling, and biological processes, including apoptosis and inflammation.

Conclusions/Significance

This study highlights that specific miRNAs are likely to be involved in asthma disease and could represent a valuable resource both for biological makers identification and for unveiling mechanisms underlying the pathogenesis of asthma.     

Possible Roles of mmu-miR-141 in the Endometrium of Mice in Early Pregnancy Following Embryo Implantation

Objective

Embryo implantation is directly affected by genes related to uterine receptivity. Studies have demonstrated the important roles of miRNAs in the regulation of gene expression. Our early miRNA chip analyses revealed that the mmu-miR-141 expression in endometrial tissue is lower after embryo implantation than before it. However, the possible roles of miR-141 in embryo implantation have not yet been elucidated. Here, mmu-miR-141 was designed to detect the expression and role of miR-141 in the endometria of mice in early pregnancy following embryo implantation.

Methods

Real-time PCR and in-situ hybridization were used to study mmu-miR-141 expression in mouse uterus. Cell proliferation was detected by tetrazolium dye (MTT) assay and flow cytometry. Real-time PCR and Western blot analysis were used to confirm the mRNA and protein levels of phosphatase and tensin homolog (PTEN) to determine whether it was the target gene of mmu-miR-141. Enhanced green fluorescent protein (EGFP) fluorescence reporter vector analysis was also performed. A functional study was performed by injecting mice uteri with mmu-miR-141 inhibitor or mimic vectors.

Results

mmu-miR-141 expression was lower on day 6 (D6) than day 4 (D4) and could be increased by progesterone. Reduced mmu-miR-141 could decrease the proliferation activity of stromal cells and promote apoptosis. Upregulation of mmu-miR-141 inhibited PTEN protein expression but downregulation of mmu-miR-141 increased it, while the mRNA level remained unchanged. EGFP fluorescence reporter vector analysis showed that miR-141 targets the 3′-untranslated region of the PTEN mRNA. In addition, when the physiological mmu-miR-141 level was altered on D2 by injecting with inhibitor or mimic, the embryo implantation sites were significantly decreased on D7.

Conclusions

This study demonstrated that mmu-miR-141 might influence cell proliferation and apoptosis in the endometrium by negatively regulating PTEN expression, and could also influence the number of embryo implantation sites. mmu-miR-141 plays an essential role in embryo implantation.     

miR-1207-5p and miR-1266 suppress gastric cancer growth and invasion by targeting telomerase reverse transcriptase

hTERT is the catalytic subunit of the telomerase complex. Elevated expression of hTERT is associated with the expansion and metastasis of gastric tumor. In this study, we aimed to identify novel tumor suppressor miRNAs that restrain hTERT expression. We began our screen for hTERT-targeting miRNAs with a miRNA microarray. miRNA candidates were further filtered by bioinformatic analysis, general expression pattern in different cell lines, gain-of-function effects on hTERT protein and the potential of these effects to suppress hTERT 3′ untranslated region (3′UTR) luciferase activity. The clinical relevance of two miRNAs (miR-1207-5p and miR-1266) was evaluated by real-time RT-PCR. The effects of these miRNAs on cell growth, cell cycle and invasion of gastric cancer cells were measured with CCK-8, flow cytometry and transwell assays. Finally, the ability of these miRNAs to suppress the transplanted tumors was also investigated. Fourteen miRNAs were identified using a combination of bioinformatics and miRNA microarray analysis. Of these fourteen miRNAs, nine were expressed at significantly lower levels in hTERT-positive cell lines compared with hTERT-negative cell lines and five could downregulate hTERT protein expression. Only miR-1207-5p and miR-1266 interacted with the 3′ UTR of hTERT and the expression levels of these two miRNAs were significantly decreased in gastric cancer tissues. These two miRNAs also inhibited gastric tumor growth in vitro and in vivo. Altogether, miR-1207-5p and miR-1266 were determined to be hTERT suppressors in gastric cancer, and the delivery of these two miRNAs represents a novel therapeutic strategy for gastric cancer treatment.