microRNA and the Post-Transcriptional Response to Oxidative Stress during Neuronal Differentiation: Implications for Neurodevelopmental and Psychiatric Disorders

Oxidative stress is one of the most important environmental exposures associated with psychiatric disorders, but the underlying molecular mechanisms remain to be elucidated. In a previous study, we observed a substantial alteration of the gene expression landscape in neuron-like cells that were differentiated from SH-SY5Y cells after or during exposure to oxidative stress, with a subset of dysregulated genes being enriched for neurodevelopmental processes. To further explore the regulatory mechanisms that might account for such profound perturbations, we have now applied small RNA-sequencing to investigate changes in the expression of miRNAs. These molecules are known to play crucial roles in brain development and response to stress through their capacity to suppress gene expression and influence complex biological networks. Through these analyses, we observed more than a hundred differentially expressed miRNAs, including 80 previously reported to be dysregulated in psychiatric disorders. The seven most influential miRNAs associated with pre-treatment exposure, including miR-138-5p, miR-96-5p, miR-34c-5p, miR-1287-5p, miR-497-5p, miR-195-5p, and miR-16-5p, supported by at least 10 negatively correlated mRNA connections, formed hubs in the interaction network with 134 genes enriched with neurobiological function, whereas in the co-treatment condition, miRNA-mRNA interaction pairs were enriched in cardiovascular and immunity-related disease ontologies. Interestingly, 12 differentially expressed miRNAs originated from the DLK1-DIO3 location, which encodes a schizophrenia-associated miRNA signature. Collectively, our findings suggest that early exposure to oxidative stress, before and during prenatal neuronal differentiation, might increase the risk of mental illnesses in adulthood by disturbing the expression of miRNAs that regulate neurodevelopmentally significant genes and networks.

miR-181b-5p/SOCS2/JAK2/STAT5 axis facilitates the metastasis of hepatoblastoma

Introduction

Hepatoblastoma (HB) is a malignant liver tumor predominantly found in children and tumor metastasis is one of the main causes of poor prognosis in affected patients. The precise molecular mechanisms responsible for HB metastasis remain incompletely understood. However, there is evidence suggesting a connection between the dysregulation of microRNAs (miRNAs) and the progression of tumor metastasis in HB.

Methods

The study utilized weighted gene co-expression network analysis (WGCNA) to analyze a miRNA microarray dataset of HB. The expression of miR-181b-5p in HB tissues and cells was detected using quantitative real-time PCR. The impact of miR-181b-5p on the metastatic capacity of HB was evaluated through scratch and Transwell assays. The effects of exogenously expressing miR-181b on the metastatic phenotypes of HB cells were evaluated in vivo. Furthermore, a luciferase reporter assay was performed to validate a potential target of miR-181b-5p in HB.

Results

We found that miR-181b-5p was highly expressed in HB tissues and HB cell lines. Overexpression of miR-181b enhanced scratch healing, cell migration, and invasion abilities in vitro, as well as enhancing HB lung metastasis potential in vivo. Dual-luciferase reporter assays showed that Suppressor Of Cytokine Signaling 2 (SOCS2) was a direct target of miR-181b. The overexpression of miR-181b resulted in the suppression of SOCS2 expression, subsequently activating the epithelial-mesenchymal transition and JAK2/STAT5 signaling pathways. The rescue experiment showed that SOCS2 overexpression attenuated the effects of miR-181b on HB cells.

Conclusion

Our study showed that miR-181b promotes HB metastasis by targeting SOCS2 and may be a potential therapeutic target for HB.

miR-181b promotes angiogenesis and neurological function recovery after ischemic stroke

Promotion of new blood vessel formation is a new strategy for treating ischemic stroke. Non-coding miRNAs have been recently considered potential therapeutic targets for ischemic stroke. miR-181b has been shown to promote angiogenesis in hypoxia and traumatic brain injury model, while its effect on ischemic stroke remains elusive. In this study, we found that overexpression of miR-181b in brain microvascular endothelial cells subjected to oxygen-glucose deprivation in vitro restored cell proliferation and enhanced angiogenesis. In rat models of focal cerebral ischemia, overexpression of miR-181b reduced infarction volume, promoted angiogenesis in ischemic penumbra, and improved neurological function. We further investigated the molecular mechanism by which miR-181b participates in angiogenesis after ischemic stroke and found that miR-181b directly bound to the 3'-UTR of phosphatase and tensin homolog (PTEN) mRNA to induce PTEN downregulation, leading to activation of the protein kinase B (Akt) pathway, upregulated expression of vascular endothelial growth factors, down-regulated expression of endostatin, and promoted angiogenesis. Taken together, these results indicate that exogenous miR-181b exhibits neuroprotective effects on ischemic stroke through activating the PTEN/Akt signal pathway and promoting angiogenesis.

Cx43-Delivered miR-181b Negatively Regulates Sirt1/FOXO3a Signalling Pathway-Mediated Apoptosis on Intestinal Injury in Sepsis

INTRODUCTION

Gap junctions can transmit signals between cells, including miRNAs, leading to the amplification of adjacent cell damage. No previous study has addressed gap junctions and miRNAs in sepsis because the internal mechanism of sepsis-induced intestinal injury is complex. Therefore, we studied the relationship between connexin43 (Cx43) and miR-181b and provided a research direction for further study of sepsis.

METHODS

A mouse caecal ligation and puncture method was used to construct a mouse sepsis model. Firstly, damage to intestinal tissues at different time points was analysed. The levels of Cx43, miR-181b, Sirt1, and FOXO3a in intestinal tissues and the transcription and translation of the apoptosis-related genes Bim and puma, which are downstream of FOXO3a were analysed. Secondly, the effect of Cx43 levels on miR-181b and Sirt1/FOXO3a signalling pathway activity was explored by using the Cx43 inhibitor heptanol. Finally, luciferase assays were used to determine miR-181b binding to the predicted target sequence.

RESULTS

The results show that during sepsis, intestinal injury becomes increasingly worse with time, and the expression of Cx43 and miR-181b increase. In addition, we found that heptanol could significantly reduce intestinal injury. This finding indicates that inhibiting Cx43 regulates the transfer of miR-181b between adjacent cells, thereby reducing the activity of the Sirt1/FOXO3a signalling pathway and reducing the degree of intestinal injury during sepsis.

CONCLUSIONS

In sepsis, the enhancement of Cx43 gap junctions leads to an increase in miR-181b intercellular transfer, affects the downstream SIRT1/FOXO3a signalling pathway and causes cell and tissue damage.

Salivary miRNAs Expression in Potentially Malignant Disorders of the Oral Mucosa and Oral Squamous Cell Carcinoma: A Pilot Study on miR-21, miR-27b, and miR-181b

(1) Background: Oral potentially malignant disorders (OPMD) represent a fundamental challenge for clinicians, considering the possibility of progression into oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC). Several studies have examined the expression of miRNAs in humans as diagnostic and prognostic biomarkers. Among these, miR-21, miR-27b, and miR-181b proved to be promising. This cohort study evaluated the different expressions of those miRNAs in the saliva of patients with OPMD and OSCC. (2) Methods: Patients with a clinical diagnosis of OPMD and/or OSCC were enrolled; saliva samples were collected; miRNAs were extracted and quantified via qRT-PCR was performed. Data were analyzed by subgroups based on the histopathological diagnosis (OSCC and the grade of OED) using the ΔΔCt method. Saliva from 10 healthy donors was used as the control. One-way ANOVA and Kruskal-Wallis tests were performed to assess the differences between groups. (3) Results: 23 patients for the OPMD group (6 with no dysplasia, 7 with low-grade, and 10 with high-grade dysplasia) and 10 with OSCC were analyzed. MiR-21 did not show any variation among groups; miR-27b was under-expressed in dysplastic lesions (p = 0.046); miR-181b was upregulated in high-grade dysplasia (p = 0.006), increasing with the degree of dysplasia, and decreasing in OSCCs. (4) Conclusions: Salivary miR-27b and miR-181b could be promising biomarkers for oral dysplasia. Further studies are needed to clarify their feasibility.

SNP rs322931 (C>T) in miR-181b and rs7158663 (G>A) in MEG3 aggravate the inflammatory response of anal abscess in patients with Crohn's disease

BACKGROUND

The MEG3/miR-181b signaling has been implicated in the pathogenesis of several diseases including Crohn's disease. This work aimed to study the correlation between SNPs in MEG3/miR-181b and the severity of anal abscess in patients with Crohn's disease.

METHODS

Quantitative real-time PCR was performed to analyze the expression of MEG3 and miR-181b. ELISA was carried out to examine the expression of TNF-α, IL-1β, IL-6, CRP, SSA, AAT, AAG and HPT in the peripheral blood of patients with Crohn's disease. Luciferase assay was performed to explore the role of miR-181b in the expression of MEG3 and TNF-α.

RESULTS

The expression of MEG3 and miR-181b in the peripheral blood of patients with Crohn's disease was remarkably associated with the rs322931 and rs7158663 polymorphisms. rs322931 (C>T) in miR-181b and rs7158663 (G>A) in MEG3 significantly promoted the expression of TNF-α, IL-1β, IL-6, CRP, SSA, AAT, AAG and HPT. Luciferase assay demonstrated that miR-181b was capable of repressing the expression of MEG3 and TNF-α through binding to their specific binding sites. Moreover, alteration of MEG3 and miR-181b expression also showed a remarkable impact on the MEG3/miR-181b/TNF-α signaling pathway in THP-1 cells.

CONCLUSIONS

In conclusion, our study demonstrated that two SNPs, rs322931 (C>T) in miR-181b and rs7158663 (G>A) in MEG3, could aggravate the inflammatory response of anal abscess in patients with Crohn's disease via modulating the MEG3/miR-181b/TNF-α signaling pathway.

Deciphering the Role of microRNAs in Large-Artery Stiffness Associated With Aging: Focus on miR-181b

Large artery stiffness (LAS) is a major, independent risk factor underlying cardiovascular disease that increases with aging. The emergence of microRNA signaling as a key regulator of vascular structure and function has stimulated interest in assessing its role in the pathophysiology of LAS. Identification of several microRNAs that display age-associated changes in expression in aorta has focused attention on defining their molecular targets and deciphering their role in age-associated arterial stiffening. Inactivation of the microRNA-degrading enzyme, translin/trax, which reverses the age-dependent decline in miR-181b, confers protection from aging-associated arterial stiffening, suggesting that inhibitors targeting this enzyme may have translational potential. As LAS poses a major public health challenge, we anticipate that future studies based on these advances will yield innovative strategies to combat aging-associated arterial stiffening.

Cataloging recent advances in epigenetic alterations in major mental disorders and autism

During the last two decades, diverse epigenetic modifications including DNA methylation, histone modifications, RNA editing and miRNA dysregulation have been associated with psychiatric disorders. A few years ago, in a review we outlined the most common epigenetic alterations in major psychiatric disorders (e.g., aberrant DNA methylation of DTNBP1, HTR2A, RELN, MB-COMT and PPP3CC, and increased expression of miR-34a and miR-181b). Recent follow-up studies have uncovered other DNA methylation aberrations affecting several genes in mental disorders, in addition to dysregulation of many miRNAs. Here, we provide an update on new epigenetic findings and highlight potential origin of the diversity and inconsistencies, focusing on drug effects, tissue/cell specificity of epigenetic landscape and discuss shortcomings of the current diagnostic criteria in mental disorders.

CARD11 is a novel target of miR-181b that is upregulated in chronic lymphocytic leukemia

Aim: To investigate the targets of miR-181b in patients with chronic lymphocytic leukemia (CLL). Materials & methods: The bioinformatic softwares were used to indicate the key target genes associated with miR-181b, and the results were verified in CLL patient samples and 293T cells. Results: CARD11 is a potential target gene of miR-181b, an inverse relationship was revealed between the expression of CARD11 and miR-181b in 104 CLL patients, and it was confirmed in vitro with luciferase assays and western blotting. Kaplan-Meier analysis showed that CLL patients with high CARD11 expression demonstrated poor survival. Conclusion: CARD11 is a novel target of miR-181b that is upregulated, which could be a poor prognostic indicator for CLL patients.

Long non-coding RNA TUG1 promotes airway remodeling and mucus production in asthmatic mice through the microRNA-181b/HMGB1 axis

MicroRNA-181b (miR-181b) has been well noted with anti-inflammatory properties in several pathological conditions. It has also been suggested to be downregulated in patients with asthma. In this study, we explored the function of miR-181b in airway remodeling in asthmatic mice and the molecular mechanism. A mouse model with asthma was induced by ovalbumin (OVA) challenge, and miR-181b was found to be downregulated in lung tissues in the OVA-challenged mice. Overexpression of miR-181b was introduced in mice, after which the respiratory resistance, inflammatory infiltration, mucus production, and epithelial-mesenchymal transition (EMT) and fibrosis in mouse airway tissues were decreased. The integrated bioinformatics analysis suggested long non-coding RNA (lncRNA) TUG1 as a sponge for miR-181b. miR-181 directly targeted high mobility group box 1 (HMGB1) mRNA. HMGB1 was suggested to enhance activation of the nuclear factor kappa B (NF-κB) signaling. Further upregulation of lncRNA TUG1 blocked the protective functions of miR-181b in asthmatic mice. To conclude, this study evidenced that lncRNA TUG1 reinforces HMGB1 expression through sequestering microRNA-181b, which activates the NF-κB signaling pathway and promotes airway remodeling in asthmatic mice. This study may provide novel ideas in asthma management.

miR-181b and miR-204 suppress the VSMC proliferation and migration by downregulation of HCK

BACKGROUND

VSMC proliferation and migration pathways play important roles in plaque formation in the vessel stenosis and re-stenosis processes. The microRNAs affect the expression of many genes that regulate these cellular processes. The aim of this study was to investigate the effects of miR-181b, miR-204, and miR-599 on the gene and protein expression levels of hematopoietic cell kinase (HCK) in VSMCs.

METHODS

miR-181b, miR-204 were predicted for the suppression of HCK in the chemokine signaling pathway using bioinformatics tools. Then, the VSMCs were transfected by PEI-containing microRNAs. The HCK gene and protein expression levels were evaluated using RT-qPCR and Western blotting techniques, respectively. Moreover, the cellular proliferation and migration were evaluated by MTT and scratch assay methods.

RESULTS

The miR-181b and miR-204 decreased significantly the HCK gene and (total and phosphorylated) protein expression levels. Also, the miR-599 did not show any significant effects on the HCK gene and protein levels. The data also showed that miR-181b, miR-204, and miR-599 prevent significantly the proliferation and migration of VSMCs.

CONCLUSION

The downregulation of HCK by miR-181b and miR-204 suppressed the VSMC proliferation and migration.

LncRNA p21, downregulating miR-181b, aggravates neuropathic pain by upregulating Tnfaip1 and inhibit the AKT/CREB axis

Recently, there is evidence that long non-coding RNA p21 may play a regulatory role in the development of neuropathic pain (NPP), but it remains to be studied. In this study, we found that lncRNA p21 and tumor necrosis factor alpha-induced protein 1 (Tnfaip1) expression were up-regulated and miR-181b expression was down-regulated in lipopolysaccharide (LPS)-induced and activated BV-2 microglia. The results of flow cytometry and ELISA suggested that overexpression of lncRNA p21 or Tnfaip1 promoted apoptosis and inflammatory factors secretion, and miR-181b overexpression inhibited apoptosis and secretion of inflammatory factors. Luciferase reporter gene analysis validated the adsorption of miR-181b by lncRNA p21. In addition, the targeting relationship between miR-181b and Tnfaip1 was determined. Next, the up-regulation of lncRNA p21 and miR-181b was used as a reversal experiment, and the results suggested that the up-regulation of miR-181b attenuated the promoting effect of lncRNA p21 and Tnfaip1 on apoptosis and inflammatory response, which may be related to the activation of AKT/cAMP response element binding protein (CREB) axis. Finally, the rat model of SNL with lncRNA p21 knockdown was constructed, and the results of paw retraction mechanical threshold (PWMT) and paw retraction thermal latency (PWTL) measurements showed that knockdown of lncRNA p21 alleviated neuropathic pain in rats. In conclusion, our study found that the lncRNA p21/miR-181b/Tnfaip1 axis probably plays an important role in the progression of neuropathic pain, among which lncRNA p21 may become a new insight in the treatment of neuropathic pain.

Papillary Thyroid Carcinoma Tissue miR-146b, -21, -221, -222, -181b Expression in Relation with Clinicopathological Features

We analyzed miR-146b, miR-21, miR-221, miR-21, and miR-181b in formalin fixed paraffin-embedded papillary thyroid carcinoma (PTC) tissue samples of 312 individuals and evaluated their expression relationship with clinicopathological parameters. A higher expression of miR-21 was related to unifocal lesions (p < 0.011) and autoimmune thyroiditis (0.007). miR-221, miR-222 expression was higher in the PTC tissue samples with extrathyroidal extension (p = 0.049, 0.003, respectively). In a group of PTC patients with pT1a and pT1b sized tumors, the expression of miR-146b, miR-21, miR-221, and miR-222 in PTC tissue samples was lower than in patients with pT2, pT3, and pT4 (p = 0.032; 0.0044; 0.003; 0.001; 0.001, respectively). Patients with lymph node metastases had higher expression of miR-21, -221, -222, and -181b (p < 0.05). A high expression of miR-146b, miR-21, miR-221 panel was associated with decreased overall survival (OS) (Log rank p = 0.019). Univariate analysis revealed that presence of metastatic lymph nodes and high expression of miR-146b, miR-21, and miR-221 panels were associated with increased hazard of shorter OS. After multivariate analysis, only sex (male) and age (≥55 years) emerged as independent prognostic factors associated with shorter OS (HR 0.28 (95% CI 0.09–0.86) and HR 0.05 (95% CI 0.01–0.22), respectively). In conclusion, 5 analyzed miRs expression have significant relations to clinicopathologic parameters so further investigations of these molecules are expedient while searching for prognostic PTC biomarkers.

CircCSNK1G3 up-regulates miR-181b to promote growth and metastasis via TIMP3-mediated epithelial to mesenchymal transitions in renal cell carcinoma

Renal cell carcinoma (RCC) is the most common form of kidney cancer, with a high recurrence rate and metastasis capacity. Circular RNAs (circRNAs) have been suggested to act as the critical regulator in several diseases. This study is designed to investigate the role of circCSNK1G3 on RCC progression. We observed a highly expression of circCSNK1G3 in RCC tissues compared with normal tissues. The aberrantly circCSNK1G3 promoted the tumour growth and metastasis in RCC. In the subsequent mechanism investigation, we discovered that the tumour‐promoting effects of circCSNK1G3 were, at least partly, achieved by up‐regulating miR‐181b. Increased miR‐181b inhibits several tumour suppressor gene, including CYLD, LATS2, NDRG2 and TIMP3. Furthermore, the decreased TIMP3 leads to the enhanced epithelial to mesenchymal transition (EMT) process, thus promoting the cancer metastasis. In conclusion, we identified the oncogenic role of circCSNK1G3 in RCC progression and demonstrated the regulatory role of circCSNK1G3 induced miR‐181b expression, which leads to TIMP3‐mediated EMT process, thus resulting in tumour growth and metastasis in RCC. This study reveals the promise of circCSNK1G3 to be developed as a potential diagnostic and prognostic biomarker in the clinic. And the roles of circCSNK1G3 in cancer research deserve further investigation.

Enhanced Expression of miR-181b in B Cells of CLL Improves the Anti-Tumor Cytotoxic T Cell Response

The clinical progression of B cell chronic lymphocytic leukemia (CLL) is associated with immune cell dysfunction and a strong decrease of miR-181b-5p (miR-181b), promoting the death of CLL cells. Here we investigated whether the reduction of miR-181b impairs the immune response in CLL. We demonstrate that activated CD4+ T cells increase miR-181b expression in CLL through CD40-CD40L signaling, which enhances the maturation and activity of cytotoxic T cells and, consequently, the apoptotic response of CLL cells. The cytotoxic response is facilitated by a depletion of the anti-inflammatory cytokine interleukin 10, targeted by miR-181b. In vivo experiments in NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice confirmed that miR-181b promotes the apoptotic death of CLL cells only when functional T cells are restored. Overall, our findings suggest that the reinstatement of miR-181b in CLL cells could be an exploitable adjuvant therapeutic option for the treatment of CLL.

Hypermethylation of miR-181b in monocytes is associated with coronary artery disease and promotes M1 polarized phenotype via PIAS1-KLF4 axis

Background

Dysregulated microRNAs are involved in the macrophage polarization and atherosclerotic development. Apart from microRNAs, alteration in DNA methylation is considered as one of the most frequent epigenetic changes. The purpose of the research is to investigate the altered methylation status of miR-181b in the circulating monocytes from patients with coronary artery disease (CAD) and explore the underlying mechanisms.

Methods

We examined the methylation status of miR-181b in purified circulating monocytes from patients with CAD and healthy controls. We then transfected monocytes with miR-181b mimics and determined the role of miR-181b on the phenotypic switch of macrophages and inflammatory response. DNA methylation levels determined by MethyLight PCR and pyrosequencing at the promoter of miR-181b significantly increased in CAD patients. Based on TargetScan database, we identified PIAS1 as the target gene of miR-181b and explored the interaction of miR-181b and PIAS1 by Dual-Luciferase assay, quantitative PCR and immunoblots. We also investigated the role of miR-181b and PIAS1 on macrophage polarization and inflammation.

Results

Hypermethylation at the promoter of miR-181b directly contributed to the decrease of miR-181b activity and expression. Overexpression of miR-181b reduced M1 polarization and facilitated M2 polarization determined by quantitative PCR. While knockdown of PIAS1 induced KLF4 degradation and SUMOylation in monocytes, miR-181b mimics reverse the KLF4 SUMOylation via suppression of PIAS1. Moreover, KLF4 SUMOylation by PIAS1 reversed M1 polarization induced by depletion of miR-181b in monocytes.

Conclusions

Hypermethylation of miR-181b induces M1 polarization and promotes atherosclerosis through activation of PIAS1 and KLF4 SUMOylation in macrophages.

Plasma-Derived miRNA-222 as a Candidate Marker for Papillary Thyroid Cancer

We analyzed five miRNA molecules (miR-221; miR-222; miR-146b; miR-21; miR-181b) in the plasma of patients with papillary thyroid cancer (PTC), nodular goiter (NG) and healthy controls (HC) and evaluated their diagnostic value for differentiation of PTC from NG and HC. Preoperative PTC plasma miRNA expression (n = 49) was compared with plasma miRNA in the HC group (n = 57) and patients with NG (n = 23). It was demonstrated that miR-221; miR-222; miR-146b; miR-21 and miR-181b were overexpressed in preoperative PTC plasma samples compared to HC (p < 0.0001; p < 0.0001; p < 0.0001; p < 0.0001; p < 0.002; respectively). The upregulation in tumor tissue of these miRNAs was consistent with The Cancer Genome Atlas Thyroid Carcinoma dataset. A significant decrease in miR-21; miR-221; miR-146b and miR-181b expression was observed in the plasma of PTC patients after total thyroidectomy (p = 0.004; p = 0.001; p = 0.03; p = 0.036; respectively). The levels of miR-222 were significantly higher in the preoperative PTC compared to the NG group (p = 0.004). ROC curve (receiver operating characteristic curve) analysis revealed miR-222 as a potential marker in distinguishing PTC from NG (AUC 0.711; p = 0.004). In conclusion; circulating miR-222 profiles might be useful in discriminating PTC from NG.

Triptolide Inhibits the Proliferation of HaCaT Cells Induced by IL22 via Upregulating miR-181b-5p

BACKGROUND

Evidence has been shown that triptolide was effective in the treatment of psoriasis; however, the mechanisms remain poorly understood. Thus, this study aimed to investigate the role of triptolide on the proliferation and differentiation of HaCaT cells which are treated with IL22 to mimic abnormal proliferation/differentiation in keratinocyte of psoriasis.

MATERIALS AND METHODS

HaCaT cells were transfected with miR-181b-5p antagomir for 24 h, and then exposed to 10 μM Triptolide for 24 h, following by 100 ng/mL of IL22 for 24 h. In addition, the proliferation and cell cycle distribution in HaCaT cells were assessed by immunofluorescence or flow cytometry assays, respectively.

RESULTS

Triptolide obviously upregulated the level of miR-181b-5p in HaCaT cells. In addition, triptolide significantly inhibited IL22-induced proliferation of HaCaT cells via inducing cell cycle arrest. Moreover, IL22 markedly inhibited the differentiation of HaCaT cells, and this phenomenon was reversed by triptolide treatment. In contrast, the effects of triptolide on the proliferation and differentiation in IL22-stimulated HaCaT cells were notably reversed by miR-181b-5p antagomir. Moreover, dual-luciferase assay showed that E2F5 was the direct target of miR-181b-5p in HaCaT cells. Meanwhile, upregulation of miR-181b-5p obviously decreased the level of E2F5 in HaCaT cells.

CONCLUSION

In this study, we found that triptolide could inhibit the proliferation and promote the differentiation in IL22-stimulated keratinocytes via upregulating miR-181b-5p. These data indicated that triptolide may be a potential agent for the treatment of psoriasis.

MiR-181b suppresses the progression of epilepsy by regulation of lncRNA ZNF883

BACKGROUND

Epilepsy (EP) is a very dangerous neurological disease. MiR-181b was reported to play a regulatory role during the progression of EP. However, the mechanism by which miR-181b regulates the process of EP remains unclear.

METHODS

Hippocampal neurons were extracted from rats, which were treated with magnesium-free to mimic EP in vitro. CCK-8 assay was performed to test the cell viability. Gene and protein expressions in hippocampal neurons were detected by qRT-PCR, immunofluorescence and western blot, respectively. In addition, TUNEL staining was performed to test the cell apoptosis. Finally, dual luciferase report assay was used to verify the relation between miR-181b, ZNF883 and RASSF1A.

RESULTS

Magnesium-free significantly inhibited the proliferation of hippocampal neurons, which was reversed by miR-181b mimics. In consistent, magnesium-free induced apoptosis of cells was notably inhibited by miR-181b mimics. In addition, miR-181b suppressed the progression of EP via directly targeting RASSF1A and activating PI3K/Akt signaling. Finally, upregulation of miR-181b notably suppressed the progression of EP via regulation of ZNF883.

CONCLUSION

MiR-181b suppressed the progression of epilepsy via regulation of RASSF1A and lncRNA ZNF883. Thus, miR-181b might serve as a new target for treatment of EP.

MiR-181b suppress glioblastoma multiforme growth through inhibition of SP1-mediated glucose metabolism

Background

Glucose metabolic reprogramming is a significant hallmark of malignant tumors including GBM. Previous studies suggest that microRNAs play key roles in modulating this process in GBM cells. miR-181b acts as a tumor suppressor miRNA in influencing glioma tumorigenesis. Our previous results showed that miR-181b was down-regulated in glioma cells and tissues.

Methods

The extracellular acidification rate (ECAR), colony formation assay and levels of Glut1 and PKM2 were measured to assess the glucose metabolic and proliferation changes in GBM cells overexpressing miR-181b. Immunoblotting and luciferase reporter assay were performed to confirm the expression and role of SP1 as a direct target of miR-181b. ChIP assay was used to figure out the transcriptional regulation of SP1 on Glut1 and PKM2. In vivo study was examined for the role of miR-181b in GBM cells.

Results

MiR-181b overexpression significantly reduced the glucose metabolic and colony formation ability of GBM cells. And, SP1 was confirmed as a direct target of miR-181b while upregulation of SP1 could reverse the influence of overexpression of miR-181b. Furthermore, Glut1 and PKM2 could be regulated by SP1. Finally, miR-181b could inhibit the tumor growth in vivo.

Conclusions

Our article demonstrated the inhibitory effect of miR-181b on glucose metabolism and proliferation in GBM by suppressing SP1 expression.

Assessment of miR-181b-5p, miR-23a-3p, BCL-2, and IL-6 in Peripheral Blood Mononuclear Cells of Autistic Patients; Likelihood of Reliable Biomarkers

Autism is a neurodevelopmental disorder that is recognized by stereotypic and repetitive behaviors after 2 years of old. Dysregulation of the immune system, especially inflammation which is mostly regulated by IL-6, imposes a deficit in CNS development. Along with this crucial biomarker, researchers have proposed BCL-2, micro RNA-23a-3p (miR-23a-3p), miR-181b-5p as other probable biomarkers involved in inflammation and apoptosis. The aim of the study was to evaluate the alteration in the expression of these biomarkers in a group of autism spectrum disorder (ASD) children. Peripheral blood mononuclear cells (PBMCs) were obtained from 37 autistic patients. After RNA extraction with precipitation method, the Syber green qReal-time Polymerase Chain Reaction (PCR) was performed in order to evaluate the possible alteration in the expression of IL-6, BCL-2, miR-181b-5p, and miR-23a-3p. The results were compared with healthy controls. IL-6 was significantly upregulated in ASD patients (p=0.003). On the other hand, miR-23a was upregulated and BCL-2 downregulated in ASD patients but the changes were not significant. In initial evaluations, expression changes of miR-181b-5p were not statistically significant. However, when Patients were divided into two groups of upregulated and downregulated, re-evaluation showed that both up- (p=0.005) and down-regulation (p=0.004) (i.e. changes regardless of the direction) of miR-181b were significant in autistic children. IL-6 and miR-181b-5p can have proper diagnostic values and are reliable biomarkers with high sensitivity and specificity. On the other hand, PBMC can be utilized for such studies and also evaluation of patients' condition instead of brain tissue as it is less accessible.

Evaluation of miR-181b and miR-126-5p expression levels in T2DM patients compared to healthy individuals: Relationship with NF-κB gene expression

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a progressive metabolic disorder whose prevalence is rising very fast across the world. Diagnosis of this disease in early stages (pre-diabetic stage) plays an important role in reducing mortality associated with this disorder. miRNAs, as key players in the pathogenesis of T2DM, have been investigated in several studies. Furthermore, their expression profile changes in the early stages of diabetes mellitus in body fluids such as serum, peripheral blood, and peripheral blood mononuclear cell (PBMC) have been studied. Due to their high stability and the presence of non-invasive sensitive methods for their measurement, such as real-time PCR, they can be used for early diagnosis of T2DM as a biomarker. In this experimental study, the expression levels of miR-181b, miR-126-5p, and NF-κB were measured in patients with T2DM, pre-diabetic subjects, and healthy controls in a Yazd population.

MATERIAL AND METHOD

Ninety asymptomatic subjects including 30 T2DM, 30 pre-diabetic, and 30 healthy subjects (diagnosis based on WHO criteria) were included in this study. Real-time PCR was used to measure the expression levels of miR-181b and miR-126-5p. Moreover, the NF-κB expression level was also measured to determine its relationship with these two microRNAs.

RESULT

In this study, the expression level of miR-181b and miR-126-p decreased gradually in pre-diabetic as well as T2DM subjects compared to healthy controls. Furthermore, our study showed a significant negative correlation between these two miRNAs and NF-κB for the first time.

CONCLUSION

These results introduce these anti-inflammatory miRNAs as powerful tools for early diagnosis of T2DM.

Liquiritigenin suppresses the activation of hepatic stellate cells via targeting miR-181b/PTEN axis

BACKGROUND

Liquiritigenin (LQ), an aglycone of liquiritin in licorice, has demonstrated antioxidant, anti-inflammatory and anti-tumor activities. Previously, LQ was found to inhibit liver fibrosis progression.

PURPOSE

Phosphatase and tensin homolog (PTEN) has been reported to act as a negative regulator of hepatic stellate cell (HSC) activation. However, the roles of PTEN in the effects of LQ on liver fibrosis have not been identified to date.

METHODS

The effects of LQ on liver fibrosis in carbon tetrachloride (CCl₄) mice as well as primary HSCs were examined. Moreover, the roles of PTEN and microRNA-181b (miR-181b) in the effects of LQ on liver fibrosis were examined.

RESULTS

LQ markedly ameliorated CCl₄-induced liver fibrosis, with a reduction in collagen deposition as well as α-SMA level. Moreover, LQ induced an increase in PTEN and effectively inhibited HSC activation including cell proliferation, α-SMA and collagen expression, which was similar with curcumin (a positive control). Notably, loss of PTEN blocked down the effects of LQ on HSC activation. PTEN was confirmed as a target of miR-181b and miR-181b-mediated PTEN was involved in the effects of LQ on liver fibrosis. LQ led to a significant reduction in miR-181b expression. LQ-inhibited HSC activation could be restored by over-expression of miR-181b. Further studies demonstrated that LQ down-regulated miR-181b level via Sp1. Collectively, we demonstrate that LQ inhibits liver fibrosis, at least in part, via regulation of miR-181b and PTEN.

CONCLUSION

LQ down-regulates miR-181b level, leading to the restoration of PTEN expression, which contributes to the suppression of HSC activation. LQ may be a potential candidate drug against liver fibrosis.

Deletion of the microRNA-degrading nuclease, translin/trax, prevents pathogenic vascular stiffness

Vascular stiffness plays a key role in the pathogenesis of hypertension. Recent studies indicate that the age-associated reduction in miR-181b levels in vascular smooth muscle cells (VSMCs) contributes to increased vascular stiffness. As these findings suggest that inhibiting degradation of miR-181b might prevent vascular stiffening, we have assessed whether the microRNA-degrading translin/trax (TN/TX) complex mediates degradation of miR-181b in the aorta.We found that TN^-/- mice display elevated levels of miR-181b expression in the aorta. Therefore, we tested whether TN deletion prevents vascular stiffening in a mouse model of hypertension, induced by chronic high-salt intake (4%NaCl in drinking water for 3 wk; HSW). TN^-/- mice subjected to HSW stress do not show increased vascular stiffness, as monitored by pulse wave velocity and tensile testing. The protective effect of TN deletion in the HSW paradigm appears to be mediated by its ability to increase miR-181b in the aorta since HSW decreases levels of miR-181b in WT mice, but not in TN KO mice. We demonstrate for the first time that interfering with microRNA degradation can have a beneficial impact on the vascular system and identify the microRNA-degrading TN/TX RNase complex as a potential therapeutic target in combatting vascular stiffness.NEW & NOTEWORTHY While the biogenesis and mechanism of action of mature microRNA are well understood, much less is known about the regulation of microRNA via degradation. Recent studies have identified the protein complex, translin(TN)/trax(TX), as a microRNA-degrading enzyme. Here, we demonstrate that TN/TX is expressed in vascular smooth muscle cells. Additionally, deletion of the TN/TX complex selectively increases aortic miR-181b and prevents increased vascular stiffness caused by ingestion of high-salt water. To our knowledge, this is first report describing the role of a microRNA RNAse in cardiovascular biology or pathobiology.

MicroRNA-181b blocks gensenoside Rg3-mediated tumor suppression of gallbladder carcinoma by promoting autophagy flux via CREBRF/CREB3 pathway

BACKGROUND

Gallbladder cancer (GBC) is the seventh most common gastrointestinal cancer. Suppression of autophagy contributes to cell death of gallbladder cancer. Gensenoside Rg3 sensitizes tumor cells to chemotherapeutic agents through autophagy inhibition. However, its role mechanism on the progression of GBC remains vague. The present study is aimed to explore the functional action of Rg3 on GBC progression.

METHODS

Expression of miR-181b and CREBRF in human gallbladder carcinoma specimen were determined by western blotting and qRT-PCR. Biological character of tumor cells were assessed by FACS, CCK8 and xenograft assays, respectively. Dual luciferase assay was employed to explore the targeting site of miR-181b. Autophagy flux was detected by IF staining.

RESULTS

MiR-181b expression was increased, while CREBRF expression was reduced in GBC specimens compared to adjacent normal tissues. Based on Catalogue of Somatic Mutations in Cancer (COSMIC) database (408 GBC samples), there was negative correlation between hsa-miR-181b-5p/-3p and CREBRF which was a direct targeting of miR-181b. miR-181b mimic promoted cell proliferation and autophagy, restrained cell apoptosis by regulating CREBRF/CREB3 pathway. As an anti-tumor agent, gensenoside Rg3 inhibited cell proliferation and tumor growth, while promoted cell apoptosis by inhibiting autophagy. However, exogenous miR-181b blunted Rg3-evoked anti-tumor effect possibly by inhibiting CREBRF/CREB pathway.

CONCLUSION

Collectively, these data indicates that miR-181b possibly mediates the pathologic progression of GBC by CREBRF/CREB3 signaling pathways and impairs anti-tumor effects of Rg3 on GBC development, which suggests that miR-181b might be an key switch in the process of Rg3-mediated tumor cytotoxicity in the progression of GBC.

Aberrant Expression of the miR-181b/miR-222 after Hematopoietic Stem Cell Transplantation in Patients with Acute Myeloid Leukemia

Recently, dysregulated expression of various micro RNAs has been reported in hematologic malignancies, especially AML disease which affects normal hematopoiesis in these patients and thereby contribute to clinical outcome of AML patients, associated with either poor or favorable prognosis. Herein, we evaluated the expression of miR-181b and miR-222 in acute myeloid leukemia patients and correlation with response to therapy after hematopoietic stem cell transplantation. Eighty newly diagnosed AML patients and 80 healthy controls were recruited. The expression of miR-181b and miR-222 was evaluated by real-time SYBR Green PCR method. miR-181b gene expression was significantly increased (4.7 fold) whereas miR-222 was decreased (18.3 fold) in AML patients compared to controls (P = 0.03 and P < 0.001, respectively). Both miR-181b and miR-222 were not associated with response to treatment (P > 0.05). Also, miR-181b and miR-222 were not differentially expressed in AML patients with M3 compared to non-M3 FAB subtypes (P > 0.05). miR-181b and miR-222 are aberrantly expressed in AML patients and their baseline level is not associated with response to treatment.

Hepatitis B virus X protein promotes proliferation of hepatocellular carcinoma cells by upregulating miR-181b by targeting ING5

Hepatitis B virus X protein (HBx) played a key role in the development of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Emerging evidence has demonstrated that miR-181b and the inhibitor of growth protein 5 (ING5) participated in the pathophysiological process. However, the regulatory mechanism of HBx remained unknown. The expression of miR-181b and ING5 in HCC tissues and cell lines were examined using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Cell viability was determined using the MTT method following HCC cell lines transfection. The interaction between miR-181b and ING5 was assessed by luciferase reporter assay. The nude mice tumor model was well established to evaluate the role and biological functions of HBx on the progression of HBV-related HCC in vivo. MiR-181b was upregulated and ING5 was downregulated in HCC tissues and cell lines. As suggested by the results from in vitro and in vivo experiments, HBx downregulates the expression of the miR-181b target gene ING5, resulting in the promotion of HCC cell proliferation. HBx accelerates proliferation activity of HCC cells by increasing miR-181b expression via targeting ING5, thereby influencing the progression of HBV-related HCC.

BRAF V600E mutation and microRNAs are helpful in distinguishing papillary thyroid malignant lesions: Tissues and fine needle aspiration cytology cases

AIMS

Mutations of BRAF oncogene are considered to contribute in the invasiveness and poor clinicopathologic features of papillary thyroid cancer (PTC). As a step towards understanding the underlying molecular mechanisms of this contribution, we aimed to examine the association of four microRNAs' (miR-222, -137, -214, -181b) levels with BRAFV600E and clinicopathological features in PTC tissues and fine needle aspiration (FNA) specimens.

METHODS

In total, 56 PTC and 27 benign with multinodular goiter tissue samples, 95 FNA samples, and B-CPAP and HEK293 cell lines were examined. BRAFV600E mutation was examined in PTC tissues and FNA samples. Expression of microRNAs was assessed by real-time quantitative reverse transcription-PCR.

KEY FINDINGS

The frequency of BRAFV600E in PTC tissues and FNA samples "suspicious for PTC" was 41.1 and 36.8%, respectively. MiR-222, -137, -214, and -181b were significantly upregulated in PTC tumors (P < 0.05) and in B-CPAP cell line (P < 0.001). In FNA, the expressions of miR-222, -181b and -214 were significantly elevated in patients suspected for PTC (P < 0.05), while there was no significant difference in miR-137. After adjustment for age and sex, miR-181b was associated with an increased risk of bearing BRAFV600E mutation (OR: 1.27; 95% CI: 1.01-1.61; P = 0.045) and risk of lymphovascular invasion (OR: 1.66; 95% CI: 1.01-2.72; P = 0.045); miR-137 was associated with the risk of larger tumor size (OR: 1.31; 95% CI: 1.04-1.65; P = 0.022); miR-222 was related to increase in extracapsular invasion (OR: 1.28; 95% CI: 1.04-1.57; P = 0.018).

SIGNIFICANCE

Upregulation of miR-222, -214 and -181b has been confirmed in PTC tumors, FNA samples and cell line. MiR-137 upregulation has been confirmed in PTC tumors and cell line, but not in FNA samples. MiR-222, -137 and -181b showed an association with the degree of malignancy in PTC tumors.

Role of Serum miR-181b, Proinflammatory Cytokine, and Adhesion Molecules in Behçet's Disease

Behçet's disease (BD) is a chronic multi-systemic inflammatory disease of uncertain pathogenesis and with no definitive diagnostic test. The aims of this study were to investigate serum levels of miR-181b in BD patients and to correlate this candidate biomarker with disease activity, cytokines, and adhesion molecules to identify new markers that can be used as a diagnostic tool for BD. Blood samples were collected from 96 participants who were classified according to their BD current activity form into 3 groups: healthy control, active BD, and inactive BD patients. MiR-181b was estimated by real-time polymerase chain reaction. However, high sensitive C-reactive protein (hs-CRP), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), E-selectin, and vascular cell adhesion molecule 1 (VCAM-1) levels were determined by enzyme-linked immunosorbent assay. Serum levels of miR-181b, hs-CRP, TNF-α, IL-6, E-selectin, and VCAM-1 were significantly higher in patients than in controls, but no significant difference was observed between the active and inactive BD groups. IL-6 was positively correlated with adhesion molecules, E-selectin, and VCAM-1. MiR-181b was positively correlated with hs-CRP, TNF-α, IL-6, and VCAM-1 in all subjects. In conclusion, miR-181b could play an important role in BD pathophysiology. MiR-181b could be utilized as potential biomarker for diagnosis and therapeutic targeting of BD. However, further studies with larger patient number are required to support these findings.

miR-181b regulates ER stress induced neuron death through targeting Heat Shock Protein A5 following intracerebral haemorrhage

Endoplasmic reticulum (ER) stress acts as a protein folding and contributes to neuronal damage and neurological deterioration following intracerebral hemorrhage (ICH). Heat Shock Protein A5 (HSPA5) serves as an essential regulator of the endoplasmic reticulum (ER) stress response. However, the specific mechanism has not been will identified. Primary cortical neurons from C57BL/6 mice were subjected to erythrocyte lysates. Cell viability, microRNA and HSPA5 levels, and ER stress was detected. The interaction between microRNA and the target HSPA5 was identified by dual luciferase reporter gene assay. In addition, inflammatory cytokines, brain edema, and neurological functions in ICH mice were also assessed. Erythrocyte lysates induced ER stress and neuron damage, downregulated miR-181b and upregulated HSPA5 levels. MiR-181b suppressed HSPA5 expression by directly binding its 3'-untranslated region. Correspondingly, our data demonstrated that overexpression of miR-181b attenuated erythrocyte lysates induced neuronal necrosis and apoptosis. In vivo, downregulated miR-181b increased the HSPA5 level, along with significant elevations of pro-inflammatory cytokines, brain edema, and neurological injury following ICH. HSPA5 pathway plays an important role in ER stress induced brain damage following ICH. In addition, miR-181b has neuroprotective effects that alleviates neurological injury and represents a promising therapeutic strategy in ICH.

Licochalcone A attenuates abdominal aortic aneurysm induced by angiotensin II via regulating the miR-181b/SIRT1/HO-1 signaling

Licochalcone A (LA), a chalcone derived from liquorice, exhibits multiple biological activities, including anti-oxidation and anti-inflammation. This study aimed to investigate the role and underlying mechanism of LA in the abdominal aortic aneurysm (AAA). AAA model was established by continuous infusion of 1000 ng/kg/min of angiotensin II (AngII) in ApoE ^-/- mice for 4 weeks. At 7 days before AngII administration, 5 mg/kg/day or 10 mg/kg/day of LA was intraperitoneally administered to mice and continued for 4 weeks. The characteristics and quantification of AAAs were determined in situ. Real-time PCR or western blot was used to measure mRNA or protein levels of matrix metalloproteinase 2 and matrix metalloproteinase 9; pro-inflammatory cytokines tumor necrosis factor-α, interleukin-1β, and interleukin-6; apoptosis-related proteins Bax, Bcl-2, and active caspase-3; miR-181b; Sirtuin 1 (SIRT1); and heme oxygenase-1 (HO-1). Mouse-aorta-origin vascular smooth muscle (MOVAS) cells were used to confirm the involved pathways in vitro. We found LA administration dose-dependently reduced the incidence of AngII-induced AAA, aneurysm diameter enlargement, elastin degradation, matrix metalloproteinase production, pro-inflammatory cytokines and miR-181b expression, and vascular smooth muscle cell apoptosis. It elevated SIRT1 and HO-1 expression that was suppressed by AngII. AngII enhanced miR-181b but reduced SIRT1 and HO-1 expression in MOVAS cells. In AngII-stimulated MOVAS cells, downregulation of miR-181b significantly upregulated the expression of SIRT1 and HO-1, the effect of which was abrogated by SIRT1 siRNA. Collectively, LA could attenuate AngII-induced AAA by modulating the miR-181b/SIRT1/HO-1 signaling. LA might be a potential medical therapy for small AAA.

The interplay of LncRNA ANRIL and miR-181b on the inflammation-relevant coronary artery disease through mediating NF-κB signalling pathway

This study was designed to investigate whether ANRIL affected the aetiology of coronary artery disease (CAD) by acting on downstream miR-181b and NF-κB signalling. Altogether 327 CAD patients diagnosed by angiography were included, and mice models of CAD were established. Human coronary endothelial cells (HCAECs) and human umbilical vein endothelial cells (HUVECs) were also purchased. In addition, shRNA-ANRIL, shRNA-NC, pcDNA3.1-ANRIL, miR-181b mimic, miR-181b inhibitor and miR-NC were transfected into the cells. The lipopolysaccharides (LPS) and pyrrolidine dithiocarbamate (PDTC) were also added to activate or deactivate NF-κB signalling. Both highly expressed ANRIL and lowly expressed miR-181b were associated with CAD population aged over 60 years old, with smoking history, with hypertension and hyperlipidemia, with CHOL H 4.34 mmol/L, TG ≥ 1.93 mmol/L and Hcy ≥ 16.8 μmol/L (all P < 0.05). Besides, IL-6, IL-8, NF-κB, TNF-α, iNOS, ICAM-1, VCAM-1 and COX-2 expressions observed within AD mice models were all beyond those within NC and sham-operated groups (P < 0.05). Also VEGF and HSP 70 were highly expressed within AD mice models than within NC and sham-operated mice (P < 0.05). Transfection of either pcDNA-ANRIL or miR-181b inhibitor could significantly fortify HCAECs' viability and put on their survival rate. At the meantime, the inflammatory factors and vascular-protective parameters were released to a greater level (P < 0.05). Finally, highly expressed ANRIL also notably bring down miR-181b expression and raise p50/p65 expressions within HCAECs (P < 0.05). The joint role of ANRIL, miR-181b and NF-κB signalling could aid in further treating and diagnosing CAD.

LncRNA DLX6-AS1 promoted cancer cell proliferation and invasion by attenuating the endogenous function of miR-181b in pancreatic cancer

Background

Pancreatic cancer, one of the most aggressive malignancies, ranks the fourth cause of cancer-related death worldwide. Aberrantly expressed long non-coding RNAs (lncRNAs) functioned as oncogenes or tumor suppressors in pancreatic cancer. This study aimed to determine the expression of lncRNA DLX6 antisense RNA 1 (DLX6-AS1) in pancreatic cancer tissues and to explore the DLX6-AS1-related pathway in pancreatic cancer.

Materials and methods

The gene expression levels were determined by quantitative real-time PCR, and protein expression levels were determined by western blot assay. CCK-8 assay, colony formation assay and Transwell migration and invasion assays were used to examine cell proliferation, migration and invasion. Luciferase reporter assay was used to confirm the binding between DLX6-AS1and its potential targets. In vivo study used the mouse xenograft model to test the anti-tumor effect of DLX6-AS1 knockdown.

Results

The high expression of DLX6-AS1 was observed in pancreatic cancer tissues, and high expression of DLX6-AS1 was positively correlated with larger tumor size, advanced TNM stage and lymph node metastasis. Knockdown of DLX6-AS1 dramatically impaired cancer cell proliferation, migration and invasion. MiR-181b was the downstream target of DLX6-AS1. Knockdown of miR-181b reversed the suppression of cell viability, migration and invasion abilities caused by DLX6-AS1 knockdown. MiR-181b was found to target Zinc finger E-box-binding homeobox 2 and to modulate epithelial-mesenchymal transition. Furthermore, DLX6-AS1 knockdown inhibited tumor growth and tumor metastasis in vivo.

Conclusion

Collectively, our data suggested that DLX6-AS1 promotes cancer cell proliferation and invasion by attenuating the endogenous function of miR-181b in pancreatic cancer.

MiR-181a/b induce the growth, invasion, and metastasis of neuroblastoma cells through targeting ABI1

Neuroblastoma is a pediatric malignancy, and the clinical phenotypes range from localized tumors with excellent outcomes to widely metastatic disease in which long-term survival is approximately 40%, despite intensive therapy. Emerging evidence suggests that aberrant miRNA regulation plays a role in neuroblastoma, but the miRNA functions and mechanisms remain unknown. miR-181 family members were detected in 32 neuroblastoma patients, and the effects of miR-181a/b on cell viability, invasion, and migration were evaluated in vitro and in vivo. A parallel global mRNA expression profile was obtained for neuroblastoma cells overexpressing miR-181a. The potential targets of miR-181a/b were validated. miR-181a/b expression levels were positively associated with MYCN amplification and neuroblastoma aggressiveness. Moreover, ectopic miR-181a/b expression significantly induced the growth and invasion of neuroblastoma cells in vitro and in vivo. Microarray analysis revealed that mRNAs were consistently downregulated after miR-181a overexpression, leading to cell migration. In addition, the expression of ABI1 was suppressed by miR-181a/b, and ABI1 was validated as a direct target of miR-181a/b. We concluded that miR-181a/b were significantly upregulated in aggressive neuroblastoma, which enhanced its tumorigenesis and progression by suppressing the expression of ABI1.

PTPN22 Silencing in Human Acute T-Cell Leukemia Cell Line (Jurkat Cell) and its Effect on the Expression of miR-181a and miR-181b

Purpose: T-cell acute lymphoblastic leukemia (T-ALL) is one of the most common malignancies associated with T-lymphocytes, accounting for 10 to 15 percent of ALL cases in children and 25 percent in adults. Innovative therapeutic approaches that overcome ineffective treatments on tumor cells may be a potential source of improvement in therapeutic approaches. Suppression of gene expression at transfusion level is one of the important strategies in gene therapy. The expression of PTPN22 and miR-181 genes in all types of hematologic malignancies increases and is likely to contribute to the survival and death of cells by affecting a variety of signaling pathways. The purpose of this study was to determine the role of PTPN22 inhibition by siRNA, and alteration in miR-181a and miR-181b in Jurkat cell line.

Methods: Jurkat cells were transfected with 80 pmol of siRNA to inhibit PTPN22. After that, expression of PTPN22 mRNA and transcript levels of miR-181a and miR-181b were measured with Real-time PCR after 48hrs.

Results: Experiments demonstrated that siRNA transfection resulted in significant downregulation of PTPN22 mRNA after 48 hrs in 80 pmol dose of siRNA. Moreover, transcript levels of both miR-181a and miR-181b was decreased after transfection.

Conclusion: PTPN22, miR-181a and miR-181b might be involved in progression of Jurkat cells and targeting these molecules by RNAi might confer promising tool in treatment of T-ALL.

miR-181b inhibits chemoresistance in cisplatin-resistant H446 small cell lung cancer cells by targeting Bcl-2

INTRODUCTION

MicroRNAs (miRNAs) are a group of small non-coding RNAs that affect multiple aspects of tumor biology including chemo resistance. miR-181b has been reported to modulate multidrug resistance in non-small cell lung cancer cells. This study was undertaken to determine the role of miR-181b in chemo resistance of small cell lung cancer cells.

MATERIAL AND METHODS

This study was undertaken to determine the role of miR-181b in chemoresistance of small cell lung cancer cells with use of qRt-PCR, WB, bioinformatics analysis, and double luciferase reporter system.

RESULTS

Our data showed that miR-181b was significantly downregulated in cisplatin-resistant H446 small cell lung cancer cells, compared to parental cells, compared to parental cells. Ectopic expression of miR-181b inhibited cell proliferation and invasion in cisplatin-resistant H446 cells (p = 0.023). Moreover, overexpression of miR-181b increased the susceptibility of cisplatin-resistant H446 cells to cisplatin. Mechanistic investigations demonstrated that miR-181b inhibited B-cell lymphoma-2 (Bcl-2) expression by binding to the 3'-untranslated region. Overexpression of Bcl-2 reversed miR-181b-mediated chemo sensitization, which is accompanied by a reduced apoptotic response.

CONCLUSIONS

Taken together, this work demonstrated that miR-181b might have the ability to overcome chemo resistance of small cell lung cancer cells, and restoration of this miRNA may represent a potential therapeutic strategy for improving chemo sensitivity in small cell lung cancer.

MiR-181b inhibits P38/JNK signaling pathway to attenuate autophagy and apoptosis in juvenile rats with kainic acid-induced epilepsy via targeting TLR4

OBJECTIVE

To explore the role of miR-181b in alterations of apoptosis and autophagy in the kainic acid (KA)-induced epileptic juvenile rats via modulating TLR4 and P38/JNK signaling pathway.

METHODS

Dual-luciferase reporter assay was performed to testify the targeting relationship between miR-181b and TLR4. After intracerebroventricular injection (i.c.v.) of KA, rats were injected with miR-181b agomir and TLR4 inhibitor (TAK-242). The TLR-4 activator lipopolysaccharide (LPS) was also administered into rats immediately after injection with miR-181b agomir. Quantitative real-time-polymerase chain reaction (qRT-PCR) was used for detections of miR-181b and TLR4 expressions, hematoxylin-eosin (HE) and Nissl staining for observation of the hippocampus morphological changes, and TUNEL staining for apoptosis analysis. Moreover, western blot was determined to detect TLR4 and P38/JNK pathway proteins, as well as autophagy- and apoptosis-related proteins.

RESULTS

TLR4 was identified as a direct target of miR-181b using Dual-luciferase reporter assay. KA rats injected with miR-181b agomir or TAK-242 had improved learning and memory abilities, reduced seizure severity of Racine's scale, and lessened neuron injury. Additionally, miR-181b agomir or TAK-242 could significantly inhibit P38/JNK signaling, decrease LC3II/I, Beclin-1, ATG5, ATG7, ATG12, Bax, and cleaved caspases-3, but increase p62 and Bcl-2 expression. No significances were found between KA group and KA + miR-181b + LPS group.

CONCLUSION

MiR-181b could inhibit P38/JNK signaling pathway via targeting TLR4, thereby exerting protective roles in attenuating autophagy and apoptosis of KA-induced epileptic juvenile rats.

MiR-181b regulates autophagy in a model of Parkinson's disease by targeting the PTEN/Akt/mTOR signaling pathway

OBJECTIVE

Parkinson's disease (PD) is the second most common neurodegenerative disease. Recent studies have shown that dysregulation of microRNA plays an important role in PD, and defects in autophagy are also critically associated with mechanisms underlying PD. We aim to investigate the effect of miR-181b on autophagy, particularly the involvement of miR-181b in the regulation of the phosphatase and tensin homolog (PTEN)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway and neuronal autophagy in a 1-methyl-4- phenylpyridinium iodide(MPP⁺)-induced cellular model of Parkinson's disease.

MATERIALS AND METHODS

We used MPP⁺ as a tool to construct the PD cell model, using miR-181b mimics or inhibitors to regulate the expression of miR-181b. PC12 cell viability was detected by MTT. The expression of miR-181b was determined by quantitative real-time PCR analysis. The expression of autophagy protein markers (LC3II) and PTEN/Akt/mTOR signaling proteins (PTEN, p-AKT,p-mTOR and p-p70S6K) were determined by Western blotting analysis.

RESULTS

The expression of miR-181b and autophagy-related proteins was gradually decreased with increasing MPP⁺ content. Overexpression of miR-181b significantly decreased the LC3II/GAPDH ratio and increased cell viability compared to the MPP⁺ treated group, whereas inhibition of miR-181b attenuated these effects. In addition, we observed that PTEN expression was reduced by miR-181b mimics and induced by its inhibitors in MPP⁺-treated PC12 cells. Additionally, the indicators of AKT/mTOR signaling, phosphorylated (active) AKT, mTOR and p70S6K were both increased by miR-181b mimics and decreased by its inhibitors.

CONCLUSIONS

Our results suggest that miR-181b regulates autophagy by targeting the PTEN/Akt/mTOR signaling pathway, thereby affecting cell viability in PD.

miR-181b-induced SMAD7 downregulation controls granulosa cell apoptosis through TGF-β signaling by interacting with the TGFBR1 promoter

SMAD7 disrupts the TGF-β signaling pathway by influencing TGFBR1 stability and by blocking the binding of TGFBR1 to SMAD2/3. In this study, we showed that SMAD7 attenuated the TGF-β signaling pathway in ovarian granulosa cells (GCs) by regulating TGFBR1 transcriptional activity. To function as a transcription factor, SMAD7 downregulated the mRNA levels of TGFBR1 via direct binding to the SMAD-binding elements (SBEs) within the promoter region of pig TGFBR1. We also showed that SMAD7 enhanced porcine GC apoptosis by interrupting TGFBR1 and the TGF-β signaling pathway. Interestingly, miR-181b, a microRNA that is downregulated during porcine follicular atresia, was identified to be directly targeting SMAD7 at its 3'-UTR. By inhibiting SMAD7, miR-181b could inhibit GC apoptosis by activating the TGF-β signaling pathway. Our findings provide new insights into the mechanisms underlying the regulation of the TGF-β signaling pathway by SMAD7 and miR-181b.

Experimental Demyelination and Axonal Loss Are Reduced in MicroRNA-146a Deficient Mice

Background

The cuprizone (CPZ) model of multiple sclerosis (MS) was used to identify microRNAs (miRNAs) related to in vivo de- and remyelination. We further investigated the role of miR-146a in miR-146a-deficient (KO) mice: this miRNA is differentially expressed in MS lesions and promotes differentiation of oligodendrocyte precursor cells (OPCs) during remyelination, but its role has not been examined during demyelination.

Methods

MicroRNAs were examined by Agilent Mouse miRNA Microarray in the corpus callosum during CPZ-induced demyelination and remyelination. Demyelination, axonal loss, changes in number of oligodendrocytes, OPCs, and macrophages/microglia was compared by histology/immunohistochemistry between KO and WT mice. Differential expression of target genes and proteins of miR-146a was analyzed in the transcriptome (4 × 44K Agilent Whole Mouse Genome Microarray) and proteome (liquid chromatography tandem mass spectrometry) of CPZ-induced de- and remyelination in WT mice. Levels of proinflammatory molecules in the corpus callosum were compared in WT versus KO mice by Meso Scale Discovery multiplex protein analysis.

Results

miR-146a was increasingly upregulated during CPZ-induced de- and remyelination. The absence of miR-146a in KO mice protected against demyelination, axonal loss, body weight loss, and atrophy of thymus and spleen. The number of CNP⁺ oligodendrocytes was increased during demyelination in the miR-146a KO mice, while there was a trend of increased number of NG2⁺ OPCs in the WT mice. miR-146a target genes, SNAP25 and SMAD4, were downregulated in the proteome of demyelinating corpus callosum in WT mice. Higher levels of SNAP25 were measured by ELISA in the corpus callosum of miR-146a KO mice, but there was no difference between KO and WT mice during demyelination. Multiplex protein analysis of the corpus callosum lysate revealed upregulated TNF-RI, TNF-RII, and CCL2 in the WT mice in contrast to KO mice. The number of Mac3⁺ and Iba1⁺ macrophages/microglia was reduced in the demyelinating corpus callosum of the KO mice.

Conclusion

During demyelination, absence of miR-146a reduced inflammatory responses, demyelination, axonal loss, the number of infiltrating macrophages, and increased the number of myelinating oligodendrocytes. The number of OPCs was slightly higher in the WT mice during remyelination, indicating a complex role of miR-146a during in vivo de- and remyelination.

Effects of Panax notoginseng saponins on severe acute pancreatitis through the regulation of mTOR/Akt and caspase-3 signaling pathway by upregulating miR-181b expression in rats

BACKGROUND

In China, Panax notoginseng has been used to treat oxidative stress-related diseases for a long time. Panax notoginseng saponins is an extract from Panax notoginseng Ledeb. Its therapeutic potential is related to antioxidant activity, but related mechanisms are still unclear. The study aims to assess the protection effects of Panax notoginseng saponins in the taurocholate-induced rat model of acute pancreatitis (AP) and explore underlying mechanisms.

METHODS

A rat model of severe acute pancreatitis (SAP) was established in rats induced with taurocholate. Panax notoginseng saponins was firstly administered in the treatment group via intravenous injection. After 2 h, taurocholate administration was performed. After 24 h, the expression levels of miR-181b, Beclin1, LC3-II, Akt and mTOR from pancreas tissues were measured by Western Blotting and RT-PCR. Then the expression levels of Caspase-3 and Blc-2 were determined by immunohistochemistry. Apoptosis was assessed by the TUNEL assay. Amylase and lipase in serum were determined by ELISA and pancreatic water contents in pancreatic tissue were measured. After eosin and hematoxylin staining, the histologic analysis was performed.

RESULTS

After SAP induction by taurocholate and the treatment with Panax notoginseng saponins for 24 h, we detected the up-regulated miR-181b, the reduced Bcl-2 expression, the increased activity of mTOR/Akt, the blocked Beclin1 and LC3-II expressions, and the enhanced Caspase-3 expression. Serum lipase and amylase levels were significantly decreased in the treatment group of Panax notoginseng saponins compared to the control group. Histological analysis results verified the attenuation effects of Panax notoginseng saponins on taurocholate-induced pancreas injury, apoptosis, and autophagy.

CONCLUSION

By up-regulating the miR-181b expression level, Panax notoginseng saponins significantly reduced taurocholate-induced pancreas injury and autophagy and increased apoptosis. The significant protection effects of Panax notoginseng saponins suggested its potential in treating taurocholate induced-acute pancreatitis.

MIAT promotes proliferation and hinders apoptosis by modulating miR-181b/STAT3 axis in ox-LDL-induced atherosclerosis cell models

BACKGROUND

Plenty of lncRNAs and microRNAs have been identified to be critical mediators in the progression of atherosclerosis (AS). Myocardial infarction-associated transcript (MIAT) were aberrantly high expressed and closely associated with the pathogenesis of AS. However, its molecular mechanism has not been well characterized.

METHODS

The expression patterns of MIAT and microRNA-181b (miR-181b) in clinical samples and cells were measured by RT-qPCR assays. Luciferase reporter assay and RIP assays were used to manifest the potential interaction between MIAT, miR-181b and signal transducer and activator of transcription 3 (STAT3). Cell Counting Kit-8 (CCK-8), Propidium Iodide (PI) staining, Terminal dexynucleotidyl transferase(TdT)-mediated dUTP nick end labeling (TUNEL) and western blot assays were carried out to detect cell proliferation, cell cycle distribution, apoptosis, and STAT3 protein level, respectively.

RESULTS

MIAT expression was up-regulated and miR-181b expression was down-regulated in AS patients serum and oxidized low-density lipoprotein (ox-LDL) induced AS cells model. MIAT facilitated cell proliferation, accelerated cell cycle progression and inhibited apoptosis in ox-LDL-induced AS cell lines, while this effect was partly reversed by miR-181b overexpression. Moreover, MIAT enhanced STAT3 expression through sequestering miR-181b as a molecular sponge. Furthermore, MiR-181b hindered cell growth, induced cell cycle arrest and promoted apoptosis by directly targeting STAT3.

CONCLUSION

MIAT performed as an induction factor of AS by regulating miR-181b/STAT3 axis in ox-LDL-induced AS cell lines, offering a new insight into the potential application of MIAT in AS treatment.

CDX2 is involved in microRNA-associated inflammatory carcinogenesis in gastric cancer

The development of gastric cancer is significantly associated with chronic inflammation, such as caused by Helicobacter pylori (H. pylori) infection. Caudal-type homeobox 2 (CDX2) is a homeobox protein involved in intestinal differentiation in normal and in aberrant locations, and is associated with inflammation. The authors of the present study have previously reported that CDX2 may have a suppressive role in the progression and carcinogenesis of gastric carcinoma. In the present study, the authors initially confirmed that a decreased expression of CDX2, as detected by immunohistochemistry, is associated with poor cancer-specific survival in 210 gastric cancer cases, which is consistent with several previously published studies. To elucidate the potential mechanisms underlying this association, the authors investigated the mechanism of CDX2 suppression, which included interleukin (IL)-6/signal transducer and activator of transcription 3 (STAT3) and p53 signaling pathways. The present study confirmed that CDX2 was suppressed by activation of the IL-6/STAT3 signaling pathway via miR-181b in vitro. It was further revealed that gastric cancer with negative CDX2 expression is associated with negative p53 staining, and this association was particularly significant in undifferentiated gastric cancer. The activation of the IL-6/STAT3 signaling pathway suppressed miR-34a, which is induced by p53. This suggests that the activation of the IL-6/STAT3 signaling pathway inflammation signaling pathway suppresses the p53 signaling pathway in tumors without TP53 mutation, which results in poor prognostic outcomes. In conclusion, CDX2 may be a useful prognostic biomarker for gastric cancer and is associated with p53 inactivation.

Small RNA-seq during acute maximal exercise reveal RNAs involved in vascular inflammation and cardiometabolic health: brief report

Exercise improves cardiometabolic and vascular function, although the mechanisms remain unclear. Our objective was to demonstrate the diversity of circulating extracellular RNA (ex-RNA) release during acute exercise in humans and its relevance to exercise-mediated benefits on vascular inflammation. We performed plasma small RNA sequencing in 26 individuals undergoing symptom-limited maximal treadmill exercise, with replication of our top candidate miRNA in a separate cohort of 59 individuals undergoing bicycle ergometry. We found changes in miRNAs and other ex-RNAs with exercise (e.g., Y RNAs and tRNAs) implicated in cardiovascular disease. In two independent cohorts of acute maximal exercise, we identified miR-181b-5p as a key ex-RNA increased in plasma after exercise, with validation in a separate cohort. In a mouse model of acute exercise, we found significant increases in miR-181b-5p expression in skeletal muscle after acute exercise in young (but not older) mice. Previous work revealed a strong role for miR-181b-5p in vascular inflammation in obesity, insulin resistance, sepsis, and cardiovascular disease. We conclude that circulating ex-RNAs were altered in plasma after acute exercise target pathways involved in inflammation, including miR-181b-5p. Further investigation into the role of known (e.g., miRNA) and novel (e.g., Y RNAs) RNAs is warranted to uncover new mechanisms of vascular inflammation on exercise-mediated benefits on health.NEW & NOTEWORTHY How exercise provides benefits to cardiometabolic health remains unclear. We performed RNA sequencing in plasma during exercise to identify the landscape of small noncoding circulating transcriptional changes. Our results suggest a link between inflammation and exercise, providing rich data on circulating noncoding RNAs for future studies by the scientific community.

Prognostic value of miRNA-181a/b in colorectal cancer: a meta-analysis

AIMS

miR-181a and miR-181b have been investigated as prognostic biomarkers of colorectal cancer (CRC). However, there is controversy about the role of miR-181a and miR-181b in predicting CRC prognosis. Therefore, we performed this meta-analysis to evaluate prognostic values of miR-181a and miR-181b in CRC patients.

MATERIALS & METHODS

Studies were systemically searched from publications and analyzed, and 999 CRC cases in nine studies were examined in this meta-analysis.

RESULTS

Hazard ratio for overall survival of high miR-181a and miR-181b expression in CRC was 1.65. More prominent predictive effects were observed in black people, miR-181b group and small-sample-size group.

CONCLUSION

High levels of miR-181a and miR-181b predict poor overall survival in CRC patients. miR-181a and miR-181b are promising biomarkers for CRC prognosis.

Construction of competitive endogenous RNA network reveals regulatory role of long non-coding RNAs in type 2 diabetes mellitus

Increasing epidemic of type 2 diabetes mellitus (T2DM) and its comorbidities makes it urgent to understand the pathogenesis and regulatory mechanism. However, little is known about the regulatory role of lncRNAs in diabetes. Here, we constructed a T2DM‐related competitive endogenous RNA (ceRNA) network (DMCN) to explore biological function of lncRNAs during the development of diabetes mellitus. This network contained 351 nodes including 98 mRNAs, 86 microRNAs and 167 lncRNAs. Functional analysis showed that the mRNAs in DMCN were annotated into some diabetes‐related pathways. Furthermore, mTOR‐centred subnetwork was extracted and ncRNA‐involved mTOR pathway was established. Finally, we validated that NEAT1 was potentially communicated with mTOR signalling target protein mLST8 via the association with miR‐181b. These findings provide significant insight into lncRNA regulatory network in T2DM.

MicroRNA-181b-5p, ETS1, and the c-Met pathway exacerbate the prognosis of pancreatic ductal adenocarcinoma after radiation therapy

Preoperative chemoradiation therapy (CRT) for pancreatic ductal adenocarcinoma (PDAC) has emerged as a reasonable strategy that shows good prognostic impact. However, after preoperative CRT, resected specimens show remnant tumor cells, which indicate that some tumor cells had acquired or were selected for resistance to CRT. Recently, two oncological mechanisms, the EMT and the presence of CSCs, were reported to be associated with resistance in various cancers. Previous reports showed that HGF could induce EMT in PDAC cells; moreover, the HGF receptor, c‐Met, was identified as a dominant pancreatic CSC marker. However, the clinical significance of c‐Met expression remains unclear. So, we hypothesized that remnant PDAC tissue after CRT might harbor cells with high c‐Met expression, and these cells may exacerbate patients’ prognosis. In the immunohistochemical analysis, we showed that preoperative CRT was significantly associated with high c‐Met expression; moreover, high c‐Met expression was a significant marker of a dismal prognosis. Next, we investigated mechanisms of c‐Met upregulation in PDAC cells. We established GEM‐resistant and radioresistant PDAC cells to analyze the transcriptome involved in c‐Met expression. The microarray data for the established radiation‐resistant PDAC cells indicated miR‐181b‐5p downregulation, which targets ETS1, one of the transcription factors for c‐Met, and it was shown that radiation exposure induced c‐Met expression through ETS1 increase by the suppression of miR‐181b‐5p. These results suggested that targeting these mechanisms may promote the development of a novel multidisciplinary treatment strategy for improving preoperative CRT efficiency.

The clinical characteristics and prognostic significance of AID, miR-181b, and miR-155 expression in adult patients with de novo B-cell acute lymphoblastic leukemia

This study aimed to investigate clinical characteristics and prognostic significance of activation-induced cytidine deaminase (AID) gene, miR-181b and miR-155 expression in de novo adult B-cell acute lymphoblastic leukemia (B-ALL) patients. Results showed that AID and miR-155 expression were higher in B-ALL patients than healthy controls, while miR-181b expression was lower in B-ALL patients. In addition, Ph⁺ B-ALLs had higher AID expression than Ph^- B-ALLs, and its high expression was associated with BCR-ABL. Moreover, B-ALL patients with AID^high or miR-181b^low expression had a shorter overall survival (OS). AID^high with miR-181b^low, AID^high with miR-155^low, miR-181b^low, miR-155^low, AID^high with miR-181b^low and miR-155^low expression were associated with shorter OS. Combination of the three molecules are more accurate predictors for unfavorable OS compared with univariate group. Therefore, AID, miR-181b and miR-155 provide clinical prognosis of adult de novo B-ALL patients and may refine their molecular risk classification.

MiR-181b Antagonizes Atherosclerotic Plaque Vulnerability Through Modulating Macrophage Polarization by Directly Targeting Notch1

Atherosclerotic plaque vulnerability is the major cause for acute stroke and could be regulated by macrophage polarization. MicroRNA-181b (miR-181b) was involved in macrophage differential. Here, we explore whether miR-181b could regulate atherosclerotic plaque vulnerability by modulating macrophage polarization and the underline mechanisms. In acute stroke patients with atherosclerotic plaque, we found that the serum level of miR-181b was decreased. Eight-week apolipoprotein E knockout (ApoE^-/-) mice were randomly divided into three groups (N = 10): mice fed with normal saline (Ctrl), mice fed with high-fat diet, and tail vein injection with miRNA agomir negative control (AG-NC)/miR-181b agomir (181b-AG, a synthetic miR-181b agonist). We found that the serum level of miR-181b in AG-NC group was lower than that in Ctrl group. Moreover, 181b-AG could upregulate miR-181b expression, reduce artery burden and attenuate atherosclerotic plaque vulnerability by modulating macrophage polarization. In RAW264.7 cells treated with oxidized low-density lipoprotein (ox-LDL), we found miR-181b could reverse the function of ox-LDL on M1/M2 markers at both mRNA and protein levels. Furthermore, by employing luciferase reporter assay, we found that Notch1 was a direct target of miR-181b and could be regulated by miR-181b in vivo and in vitro. Finally, inhibition of Notch1 could abolish the function of downregulating miR-181b on increasing M2 phenotype macrophages. Our study demonstrates that administration of miR-181b could reduce atherosclerotic plaque vulnerability partially through modulating macrophage phenotype by directly targeting Notch1.

miR-181b functions as an oncomiR in colorectal cancer by targeting PDCD4

Programmed cell death 4 (PDCD4) is a RNA-binding protein that acts as a tumor suppressor in many cancer types, including colorectal cancer (CRC). During CRC carcinogenesis, PDCD4 protein levels remarkably decrease, but the underlying molecular mechanism for decreased PDCD4 expression is not fully understood. In this study, we performed bioinformatics analysis to identify miRNAs that potentially target PDCD4. We demonstrated miR-181b as a direct regulator of PDCD4. We further showed that activation of IL6/STAT3 signaling pathway increased miR-181b expression and consequently resulted in downregulation of PDCD4 in CRC cells. In addition, we investigated the biological effects of PDCD4 inhibition by miR-181b both in vitro and in vivo and found that miR-181b could promote cell proliferation and migration and suppress apoptosis in CRC cells and accelerate tumor growth in xenograft mice, potentially through targeting PDCD4. Taken together, this study highlights an oncomiR role for miR-181b in regulating PDCD4 in CRC and suggests that miR-181b may be a novel molecular therapeutic target for CRC.