miR-181c, a potential mediator for acute kidney injury in a burn rat model with following sepsis

BACKGROUND

The miRNA profile is changed after burn or sepsis and is involved in regulating inflammatory reactions. However, the function and molecular mechanism of miRNAs in regulating burn sepsis-induced acute kidney injury (AKI) are still unclear.

METHODS

In this study, animal and cell sepsis models were established after burned rats were injected with lipopolysaccharide (LPS) or NRK-52E cells treated with LPS, respectively. Cytokine expression, inflammatory cell infiltration, serum creatinine (Scr) and kidney injury molecule-1 (KIM-1) levels were analysed after the indicated treatments.

RESULTS

Burn sepsis increased the expression of inflammatory factors (TNF-α and IL-1β) and chemokines (MIP-1α, MIP-2 and MCP-1). Moreover, burn sepsis promoted macrophage and neutrophil infiltration into the kidney and upregulated the levels of Scr and KIM-1 in the kidney and urine. Ectopic expression of miR-181c significantly reduced LPS-induced TLR4 protein expression, suppressed KIM-1 mRNA levels and subsequently inhibited the activation of inflammatory genes (TNF-α and IL-1β) and chemokine genes (MIP-1α, MIP-2 and MCP-1).

CONCLUSIONS

Our results demonstrated that miR-181c could suppress TLR4 expression, reduce inflammatory factor and chemokine secretion, mitigate inflammatory cell infiltration into the kidney and downregulate KIM-1 expression, which might ultimately attenuate burn sepsis-induced AKI.

Trehalose Attenuates Learning and Memory Impairments in Aged Rats via Overexpression of miR-181c

MicroRNAs have been recognized as important regulators of the aging process. Trehalose, a natural disaccharide, displays protective effects against neuronal impairment through several mechanisms. However, little is known about the interactive effects of aging and trehalose on behavioral function and underlying miRNA expression patterns in the hippocampus of young and old rats. Male Wistar rats were divided into four groups. Two groups of aged (24 months) and young (4 months) rats were administered 2% trehalose solution for 30 days. Two other groups of aged and young rats received regular tap water. At the end of treatment, rats were assessed for cognitive behavior using the Morris water maze test. The expression level of miR-181c and mir-34c was also measured by qRT-PCR. We found that trehalose treatment reduced learning and memory impairment in old rats compared to control old animals (p < 0.05). In contrast, cognitive performance was not significantly improved in trehalose-treated young rats in comparison with young controls (p > 0.05). We also showed that the expression level of miR-181c was significantly increased in trehalose-treated rats (p < 0.01). However, analysis of miR-34c expression level indicated no significant difference between trehalose-treated old rats and non-treated old animals (p > 0.05). Our results indicated that trehalose treatment improved learning and memory function in aged rats by targeting miR-181c. Therefore, trehalose administration may provide a therapeutic strategy to ameliorate age-associated cognitive impairment.

miR-181c regulates MCL1 and cell survival in GATA2 deficient cells

GATA2 is a transcription factor critical for hematopoiesis. Germline mutations in GATA binding protein 2 (GATA2) led to haploinsufficiency, severe cytopenias of multiple cell lineages, susceptibility to infections and strong propensity to develop myelodysplastic syndrome, and acute myeloid leukemia. Mechanisms of progressive cytopenias remain unclear. MicroRNA (miRNA) represents a unique mechanism of post-transcriptional gene regulation. In this study, miRNA profiles were evaluated and eight miRNAs were found to be differentially expressed (≥2-fold, P ≤ 0.05) in patient-derived cell lines (N = 13) in comparison to controls (N = 10). miR-9, miR-181a-2-3p, miR-181c, miR-181c-3p, miR-486-3p, and miR-582 showed increased expression, whereas miR-223 and miR-424-3p showed decreased expression. Cell death assays indicated that miR-181c potently induces cell death in lymphoid (Ly-8 and SP-53) and myeloid (HL-60) cell lines. miR-181c was predicted to target myeloid cell leukemia (MCL)1, which was confirmed by transfection assays, resulting in significantly reduced MCL1 mRNA and decreased live cell numbers. Bone marrow analysis of 34 GATA2 patients showed significantly decreased cellularity, CD34-positive cells, monocytes, dendritic cells, NK cells, B cells, and B cell precursors in comparison to healthy controls (N = 29; P < 0.001 for each), which was accompanied by decreased levels of MCL1 (P < 0.05). GATA2 expression led to significant repression of miR-181c expression in transfection experiments. Conversely, knockdown of GATA2 led to increased miR-181c expression. These findings indicate that miR-181c expression is increased and MCL1 levels decreased in GATA2 deficiency cells, and that GATA2 represses miR-181c transcription. Increased miR-181c may contribute to elevated cell death and cytopenia in GATA2 deficiency potentially through down-regulation of MCL1.

Evidence of A Negative Feedback Network Between TDP-43 and miRNAs Dependent on TDP-43 Nuclear Localization

TAR DNA-binding protein 43 (TDP-43) is a DNA/RNA-binding protein that is integral to RNA processing. Among these functions is a critical role in microRNA (miRNA) biogenesis through interactions with the DROSHA and DICER complexes. It has been previously shown that there is a general reduction in miRNA levels within the spinal cord and spinal motor neurons of amyotrophic lateral sclerosis (ALS) patients. In addition, the most common pathological feature of ALS is re-distribution of TDP-43 from the nucleus to the cytoplasm where it forms cytoplasmic inclusions. Among miRNAs dysregulated in ALS, several are known to regulate TDP-43 expression. In this study, we demonstrate that TDP-43 is in a regulatory negative feedback network with miR-181c-5p and miR-27b-3p that is dependent on its nuclear localization within HEK293T cells. Further, we show that cellular stress which induces a redistribution of TDP-43 from the nucleus to the cytoplasm correlates with the reduced production of miR-27b-3p and miR-181c-5p. This suggests that reduced nuclear TDP-43 disrupts a negative feedback network between itself and miRNAs. These findings provide a further understanding of altered miRNA biogenesis as a key pathogenic process in ALS.

Upregulation of Akt/Raptor signaling is associated with rapamycin resistance of breast cancer cells

mTOR inhibitors are considered today to be one of the most promising anticancer drugs. Here to study the mechanism of the acquired resistance of MCF-7 breast cancer cells to mTOR inhibitors two different models of the cell resistance were used: rapamycin-resistant MCF-7/Rap subline developed under long-term rapamycin treatment, and metformin-resistant MCF-7/M subline obtained by long-term metformin treatment. We have found that both resistant sublines were characterized by common features: increased expression of mTOR-interacting Raptor protein, increased phosphorylation of Akt, and activation of growth-related transcriptional factor AP-1. Cell response to mTOR inhibitors was partially restored under treatment with PI3K inhibitor wortmannin supporting the direct connection between Akt activation and poor cell response to therapeutic drugs. Transfection of mir-181c, one of the positive regulators of Akt and mTOR, led to an increase in the cell resistance to both mTOR inhibitors, rapamycin and metformin, which correlated with Raptor overexpression and activation of Akt/AP-1 signaling. In general, the effect of Raptor overexpression in the resistant cells, as well as the ability of mir-181c to modulate the Raptor expression, can open novel perspectives in the treatment of rapalogues-resistant cancers, based on the drugs design targeting mir-181c/Raptor axis.

MiR-181c protects cardiomyocyte injury by preventing cell apoptosis through PI3K/Akt signaling pathway

Background

Cardiomyocyte apoptosis plays an important role in the development of heart failure, which leads to high mortality in patients with cardiovascular diseases. In this study, we are focused to identify the role of miRNA-181c in the regulating of myocardial tissue apoptosis in the doxorubicin (DOX) or hypoxia/reoxygenation (H/R) induced H9C2 cardiomyocyte injury.

Methods

DOX-induced heart failure animal model was established using mice. Total RNA was extracted from tissue and cell using Trizol. RT-PCR was conducted for real-time RNA quantification. H9c2 cells were collected and labeled using an Annexin V-PI apoptosis kit. Flow cytometry was conducted to identify the cell apoptosis. Rat cardiomyocyte H9c2 cell was treated by 16 hours' hypoxia and 2 hours' reoxygenation to induce cell apoptosis. TUNEL assay was employed for myocardial tissue apoptosis analysis.

Results

It was revealed that miR-181c was suppressed on the heart tissue of DOX-induced heart failure animal model. We observed miR-181c overexpression reduced apoptosis through TUNEL assay, which suggested the inhibitory effect of miR-181c on myocardial tissue apoptosis. Transfection of miR-181c mimic could decrease cell apoptosis in H/R treated H9C2 cells in vitro. Under the stimulation of H/R or DOX, miR-181c could downregulate protein expression of Fas, IL-6 and TNF-α, and upregulated Bcl2 and the phosphorylation of Akt.

Conclusions

Our study revealed that miR-181c protected heart failure by impeding cardiomyocyte apoptosis through PI3K/Akt pathway, implying the therapeutic role of miR-181c during the exacerbation of the cardiovascular disease.

Nuclear-mitochondrial communication involving miR-181c plays an important role in cardiac dysfunction during obesity

AIMS

In cardiomyocytes, there is microRNA (miR) in the mitochondria that originates from the nuclear genome and matures in the cytoplasm before translocating into the mitochondria. Overexpression of one such miR, miR-181c, can lead to heart failure by stimulating reactive oxygen species (ROS) production and increasing mitochondrial calcium level ([Ca²⁺]_m). Mitochondrial calcium uptake 1 protein (MICU1), a regulatory protein in the mitochondrial calcium uniporter complex, plays an important role in regulating [Ca²⁺]_m. Obesity results in miR-181c overexpression and a decrease in MICU1. We hypothesize that lowering miR-181c would protect against obesity-induced cardiac dysfunction.

METHODS AND RESULTS

We used an in vivo mouse model of high-fat diet (HFD) for 18 weeks and induced high lipid load in H9c2 cells with oleate-conjugated bovine serum albumin in vitro. We tested the cardioprotective role of lowering miR-181c by using miR-181c/d^-/- mice (in vivo) and AntagomiR against miR-181c (in vitro). HFD significantly upregulated heart levels of miR-181c and led to cardiac hypertrophy in wild-type mice, but not in miR-181c/d^-/- mice. HFD also increased ROS production and pyruvate dehydrogenase activity (a surrogate for [Ca²⁺]_m), but the increases were alleviated in miR-181c/d^-/- mice. Moreover, miR-181c/d^-/- mice fed a HFD had higher levels of MICU1 than did wild-type mice fed a HFD, attenuating the rise in [Ca²⁺]_m. Overexpression of miR-181c in neonatal ventricular cardiomyocytes (NMVM) caused increased ROS production, which oxidized transcription factor Sp1 and led to a loss of Sp1, thereby slowing MICU1 transcription. Hence, miR-181c increases [Ca²⁺]_m through Sp1 oxidation and downregulation of MICU1, suggesting that the cardioprotective effect of miR-181c/d^-/- results from inhibition of Sp1 oxidation.

CONCLUSION

This study has identified a unique nuclear-mitochondrial communication mechanism in the heart orchestrated by miR-181c. Obesity-induced overexpression of miR-181c increases [Ca²⁺]_m via downregulation of MICU1 and leads to cardiac injury. A strategy to inhibit miR-181c in cardiomyocytes can preserve cardiac function during obesity by improving mitochondrial function. Altering miR-181c expression may provide a pharmacologic approach to improve cardiomyopathy in individuals with obesity/type 2 diabetes.

MicroRNA-181c provides neuroprotection in an intracerebral hemorrhage model

Apoptosis is an important factor during the early stage of intracerebral hemorrhage. MiR-181c plays a key regulatory role in apoptosis. However, whether miR-181c is involved in apoptosis of prophase cells after intracerebral hemorrhage remains unclear. Therefore, in vitro and in vivo experiments were conducted to test this hypothesis. In vivo experiments: collagenase type VII was injected into the basal ganglia of adult Sprague-Dawley rats to establish an intracerebral hemorrhage model. MiR-181c mimic or inhibitor was injected in situ 4 hours after intracerebral hemorrhage. Neurological functional defects (neurological severity scores) were assessed 1, 7, and 14 days after model establishment. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and western blot assay were conducted 14 days after model establishment. In vitro experiments: PC12 cells were cultured under oxygen-glucose deprivation, and hemins were added to simulate intracerebral hemorrhage in vitro. MiR-181c mimic or inhibitor was added to regulate miR-181c expression. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, luciferase reporter system, and western blot assay were performed. Experimental results revealed differences in miR-181c expression in brain tissues of both patients and rats with cerebral hemorrhage. In addition, in vitro experiments found that miR-181c overexpression could upregulate the Bcl-2/Bax ratio to inhibit apoptosis, while inhibition of miR-181c expression could reduce the Bcl-2/Bax ratio and aggravate apoptosis of cells. Regulation of apoptosis occurred through the phosphoinositide 3 kinase (PI3K)/Akt pathway by targeting of phosphatase and tensin homolog deleted on chromosome ten (PTEN). Higher miR-181c overexpression correlated with lower neurological severity scores, indicating better recovery of neurological function. In conclusion, miR-181c affects the prognosis of intracerebral hemorrhage by regulating apoptosis, and these effects might be directly mediated and regulated by targeting of the PTEN\PI3K/Akt pathway and Bcl-2/Bax ratio. Furthermore, these results indicated that miR-181c played a neuroprotective role in intracerebral hemorrhage by regulating apoptosis of nerve cells, thus providing a potential target for the prevention and treatment of intracerebral hemorrhage. Testing of human serum was authorized by the Ethics Committee of China Medical University (No. 2012-38-1) on February 20, 2012. The protocol was registered with the Chinese Clinical Trial Registry (Registration No. ChiCTR-COC-17013559). The animal study was approved by the Institutional Animal Care and Use Committee of China Medical University (approval No. 2017008) on March 8, 2017.

SPP1 functions as an enhancer of cell growth in hepatocellular carcinoma targeted by miR-181c

Patients diagnosed with hepatocellular carcinoma (HCC) suffered a high risk of recurrence and poor prognosis. Identification of differentially expressed genes (DEGs) in HCC provides potential biomarkers for evaluating prognosis and specific therapeutic treatments. In this study, DEGs over-expressed in HCC specimens with a fold change over 2.0 were collected through integrative bioinformatics analysis from GEO datasets. Gene ontology and KEGG pathway enrichment were conducted by applying DAVID database. We noticed Secreted phosphoprotein 1 (SPP1) as one of the signature genes up-regulated in HCC tissues with a close relation to the tumor process. Eighty-seven paired HCC specimens from our medical center were explored to verify the aberrant expression of SPP1 by IHC and qRT-PCR assay. Depletion of SPP1 in HCC Hep3B cells was established. The cell proliferation was impaired in SPP1 depleted cells, along with a resistance of cell apoptosis by down-regulating SPP1. Intriguingly, we further validated a direct interaction between miR-181c and SPP1, which indicated a post-transcriptional regulation mechanism of SPP1 in HCC. Thus, our results suggest that SPP1 may function as an enhancer of HCC growth targeted by miR-181c, and probably provide us an innovational target for HCC diagnose and therapeutic treatment.

Pretreatment of bone mesenchymal stem cells with miR181-c facilitates craniofacial defect reconstruction via activating AMPK-Mfn1 signaling pathways

Context: Bone mesenchymal stem cells (BMSC)-based regenerative therapy is critical for the craniofacial defect reconstruction. However, oxidative stress micro-environment after transplantation limits the therapeutic efficiency of BMSC. The miR-181c has been found to be associated with cell survival and proliferation. Objective: Herein, we investigated whether prior miR-181c treatment promoted BMSC proliferation and survival under oxidative stress injury. Materials and methods: Cells were treated with hydrogen peroxide (H₂O₂) and then cell viability was determined via MTT assay, TUNEL staining and ELISA. Western blotting and immunofluorescence assay were used to detect those alterations of mitochondrial function. Results: H₂O₂ treatment reduced BMSC viability and this effect could be reversed via additional supplementation of miR181-c. Mechanistically, oxidative stress increased cell apoptosis, augmented caspase-3 activity, promoted reactive oxygen species (ROS) synthesis, impaired mitochondrial potential, and induced mitochondrial dynamics imbalance. However, miR-181c pretreatment reversed these effects of oxidative stress on BMSC. Moreover, miR-181c treatment improved BMSC proliferation, migration and paracrine, which are very important for craniofacial reconstruction. In addition, we identified that AMPK-Mfn1 axis was the direct targets of miR-181c in BMSC. Mfn1 silencing impaired the protective effects miR-181c on BMSC viability and proliferation under oxidative stress environment. Conclusions: Collectively, our results indicate that miR-181c participates in oxidative stress-mediated BMSC damage by modulating the AMPK-Mfn1 signaling pathway, suggesting miR-181c-AMPK-Mfn1 axis may serves as novel therapeutic targets to facilitate craniofacial defect reconstruction.

Identification of microRNAs modulated by DNA hypomethylating drugs in extranodal NK/T-cell lymphoma

To identify epigenetically silenced miRNAs and to investigate their influences on predictive target oncogenes in extranodal natural killer/T-cell lymphoma (NKTCL). Decitabine treatment was performed to evaluate methylated miRNAs in NKTCL cells. The relationship between a given miRNA and its target mRNA was validated using 24 tumor tissues. miR-379, miR-134, miR-20b, miR-376a, miR-654-3p, miR-143, miR-181c, miR-1225-5p, miR-1246, and miR-1275 were epigenetically silenced in SNK6 cells. miR-134, miR-376a, miR-143 and miR-181c significantly affected cellular viability. PDGFRα was regulated by miR-34a and miR-181c. miR-143, miR-20b and miR34a regulated STAT3 expression. miR-20b and miR-143 expression showed inverse correlations with STAT3 mRNA expression in NKTCL tissues. K-RAS was regulated by miR-181c. Downregulation of cell viability by salirasib treatment was identified. miRNAs were downregulated by DNA methylation, and several microRNAs affected the viability of NKTCL cells. miR-34a and miR-181c may be involved in the oncogenic progression of NKTCL through the regulation of PDGFRα, STAT3, and K-RAS.

miR-181c expression in neuroblastoma children and proliferation of neuroblastoma M17 cells

Expression level of miR-181c in neuroblastoma children and its effect on proliferation of neuroblastoma M17 cells were investigated. Fifty-seven neuroblastoma patients admitted to Weifang People's Hospital from January 2013 to December 2017 were selected and their cancer tissues and normal adjacent tissues were obtained. The expression level of miR-181c in the tissues of neuroblastoma patients was measured. The association of miR-181c expression level with the clinical and pathological features was analyzed. Neuroblastoma M17 cells were cultured in vitro, and cells were transfected and divided into miR-181c and blank groups. MTT assay was used to observe the proliferation of cells at 24, 48 and 72 h. The results of RT-qPCR detection showed that the expression level of miR-181c was significantly lower in neuroblastoma cancer tissues than that in adjacent tissues, with a statistically significant difference (t=18.570, P<0.001). The expression of miR-181c was not associated with sex (P=0.632), but associated with age, differentiation degree, lymph node metastasis, distant metastasis and the International Neuroblastoma Risk Group Staging System (INRGSS), with statistically significant differences (P<0.05). Following transfection of miR-181c into M17 cells, the results of MTT assay showed that there was no significant difference between the two groups in the proliferation of M17 cells at 24 h (P>0.05). After 48 h, differences between the two groups were recorded. Proliferation of M17 cells was significantly lower in the miR-181c group than that in the blank group, with a statistically significant difference (P<0.05). Age, differentiation degree, lymph node metastasis, distant metastasis, and INRGSS staging were independent risk factors for neuroblastoma (P<0.05). miR-181c has certain clinical significance in evaluating pathogenesis, early diagnosis and treatment of patients with neuroblastoma.

MiR-181c affects estrogen-dependent endometrial carcinoma cell growth by targeting PTEN

MicroRNAs (miRNAs), which is a type of non-coding and single-stranded small molecule RNA, bind either completely or incompletely to 3'-UTR of the target gene mRNA to inhibit mRNA translation or degradation. In our study, we aimed to explore the roles and mechanisms of miR-181c in the apoptosis of RL95-2 human endometrial carcinoma cells. Cell activity and apoptosis were detected by cell counting Kit-8 (CCK-8) assay and flow cytometry (FCM), respectively. Related mRNAs and proteins expression was determined by quantitative real-time reverse transcription PCR (qRT-PCR) and western blot assays, respectively. The binding capacity of PTEN-3'-UTR and miR-181c was assessed by luciferase reporter assay. The obtained results suggested that E2 evidently increased the cell activity of RL95-2 cells. In addition, miR-181c inhibitor suppressed the cell viability and enhanced the apoptosis capacity of E2-induced RL95-2 cells and distinctly reduced the miR-181c expression. We also found that miR-181c could bind to PTEN-3'-UTR and miR-181c inhibitor up-regulated the expression level of PTEN in E2-induced RL95-2 cells. Besides, overexpression of PTEN markedly promoted the apoptosis of E2-induced RL95-2 cells through regulating the Bax and Bcl-2 expression, and modulated the expression of AKT pathway, p53 and Cyclin D. In conclusion, our findings revealed that miR-181c affected the estrogen-dependent endometrial carcinoma cell growth by targeting PTEN. The potential effects of miR-181c on the apoptosis of E2-induced RL95-2 cells suggest that miR-181c could be an effective target for endometrial carcinoma therapies.

MicroRNA-181c prevents apoptosis by targeting of FAS receptor in Ewing's sarcoma cells

Background

MicroRNAs (miRNAs) are endogenous, small non-coding RNAs that play important roles in multiple biological processes. Here, we show that miRNAs play an important function in the down-regulation of FAS expression in Ewing's sarcoma (ES) cells.

Methods

To identify and characterize possible oncogenic factors in ES, we employed a microarray-based approach to profile the changes in the expression of miRNAs and their target mRNAs in five ES cell lines and human mesenchymal stem cells (hMSCs).

Results

MiRNA, miR-181c, was significantly up-regulated, whereas FAS receptor expression was significantly down-regulated in all tested ES cells compared with hMSCs. Introducing anti-miR-181c into ES cell lines resulted in an increased expression of FAS2. Additionally, anti-miR-181c prohibited cell growth and cell cycle progression in ES cells. Anti-miR-181c also promoted apoptosis in ES cells. Furthermore, the down-regulation of miR-181c in ES cells significantly suppressed tumor growth in vivo.

Conclusions

These results suggest that unregulated expression of miR-181c could contribute to ES by targeting FAS. Reduction of miR181c increased expression of FAS. This proves that retardation of cell cycle progression removes apoptosis resistance, thereby repressing the growth of Ewing sarcoma. Since FAS signaling is involved in regulation of apoptosis and tumor proliferation, our findings might contribute to new therapeutic targets for ES.

High expression of miR-181c as a predictive marker of recurrence in stage II colorectal cancer

INTRODUCTION

A standard treatment for stage II colorectal cancer (CRC) is surgical resection without adjuvant chemotherapy. However, the recurrence rate of these patients is approximately 20%. To date, there are no robust biomarkers suitable for predicting recurrence in stage II CRC patients. In this study, microRNAs (miRNAs) extracted from CRC tissues were examined for a possible biomarker to predict recurrence in stage II CRC patients.

RESULTS

From the comprehensive analysis, 15 miRNAs were selected as candidates for further study. Regarding let-7a, -7d, -7e, miR-23c, -26b, -128a, -151-5p, and -181c, recurrence rates in training cohort patients with higher expression of these miRNAs isolated from their frozen tissues samples were significantly higher than those with lower expression (P < 0.05). According to multivariate analysis, the higher expression of miR-181c was detected as an independent predictive factor of recurrence (P = 0.001, OR: 9.43, 95% CI: 2.57–34.48). Results were similar in miR-181c extracted from FFPE tissues obtained from the training cohort (P = 0.003, OR: 7.46, 95% CI: 1.97–28.57). In the validation cohort using FFPE tissues, the recurrence rate in patients with higher miR-181c expression was significantly higher than those with lower miR-181c expression (P < 0.001).

MATERIAL AND METHODS

Comprehensive analysis using a highly sensitive miRNA chip was initially performed to select candidate miRNAs associated with recurrence. Candidate miRNAs were analyzed by real-time RT-PCR using RNA from frozen and formalin-fixed, paraffin-embedded (FFPE) tissues.

CONCLUSIONS

Higher expression of miR-181c may be a useful recurrence predictor of stage II CRC patients.

Upregulation of miR-181c inhibits chemoresistance by targeting ST8SIA4 in chronic myelocytic leukemia

Chemotherapy resistance frequently drives tumor progression. Increased expression of ST8SIA4 has been reported in diverse carcinomas and highly correlates with leukemia multidrug resistance (MDR). MicroRNAs (miRNA) are widely recognized as key players in cancer progression and drug resistance. Here, to explore whether miRNA modulates the sensitivity of chronic myelocytic leukemia (CML) to chemotherapeutic agents and regulates ST8SIA4 expression, we analyzed the complete miRNA expression profile and found a subset of miRNAs specifically dysregulated in adriamycin-resistant CML cell line K562/ADR and its parent cell line K562. Compared with three pairs of CML cell lines and 38 clinical samples of peripheral blood mononuclear cells (PBMC) of CML patients, miR-181c expression was down-regulated in drug-resistant cell lines and CML/MDR samples. Altered expression levels of miR-181c influenced the MDR phenotypes of K562 and K562/ADR. Reporter-gene assay showed that miR-181c directly targeted and inhibited the ST8SIA4 expression, as well as miR-181c was inversely correlated with the levels of ST8SIA4 expression in CML cell lines and samples. Moreover, ST8SIA4 could reverse the effect of miR-181c on drug resistance in K562 and K562/ADR cells in vitro. Upregulation of miR-181c sensitized K562/ADR cells to adriamycin in vivo through directly suppressing ST8SIA4 expression. Further investigation showed that miR-181c mediated the activity of phosphoinositide-3 kinase (PI3K)/AKT signal pathway, and inhibition of PI3K/Akt in K562 cells counteracted miR-181c-mediated MDR phenotype. These data revealed an important role for miR-181c in the regulation of chemoresistance in CML, and suggested the potential application of miR-181c in drug resistance treatment.

Loss of miR-107, miR-181c and miR-29a-3p Promote Activation of Notch2 Signaling in Pediatric High-Grade Gliomas (pHGGs)

The mechanisms by which microRNAs control pediatric high-grade gliomas (pHGGs) have yet to be fully elucidated. Our studies of patient-derived pHGG tissues and of the pHGG cell line KNS42 revealed down-regulation in these tumors of three microRNAs, specifically miR-107, miR-181c, and miR-29a-3p. This down-regulation increases the proliferation of KNS42 cells by de-repressing expression of the Notch2 receptor (Notch2), a validated target of miR-107 and miR-181c and a putative target of miR-29a-3p. Inhibition (either pharmacologic or genetic) of Notch2 or re-expression of the implicated microRNAs (all three combined but also individually) significantly reduced KNS42 cell proliferation. These findings suggest that Notch2 pathway activation plays a critical role in pHGGs growth and reveal a direct epigenetic mechanism that controls Notch2 expression, which could potentially be targeted by novel forms of therapy for these childhood tumors characterized by high-morbidity and high-mortality.

Dysregulation of miR-181c expression influences recurrence of endometrial endometrioid adenocarcinoma by modulating NOTCH2 expression: An NRG Oncology/Gynecologic Oncology Group study

OBJECTIVE

Endometrial cancer can be diagnosed early and cured, yet cases that recur portend a very poor prognosis with over 10,000 women succumbing to the disease every year. In this study we addressed the question of how to recognize cases likely to recur early in the course of therapy using dysregulation of tumor microRNAs (miRNAs) as predictors.

METHODS

Using the tissue collection from Gynecologic Oncology Group Study-210, we selected and analyzed expression of miRNAs in 54 recurrent and non-recurrent cases. The three most common histologic types, endometrioid adenocarcinoma (EEA), serous adenocarcinoma (ESA) and carcinosarcoma (UCS), were analyzed as three independent sets and their miRNA expression profiles compared.

RESULTS

Only one miRNA was statistically different between recurrent and non-recurrent cases, and in only one histologic type: significant down-regulation of miR-181c was observed in EEA recurrence. Using several well-known databases to assess miR-181c targets, one target of particular relevance to cancer, NOTCH2, was well supported. Using The Cancer Genome Atlas and our validation tumor panel from the GOG-210 cohort, we confirmed that NOTCH2 is significantly over-expressed in EEA. In the most relevant endometrial adenocarcinoma cell model, Ishikawa H, altering miR-181c expression produces significant changes in NOTCH2 expression, consistent with direct targeting.

CONCLUSIONS

Our findings suggest that increased NOTCH2 via loss of miR-181c is a significant component of EEA recurrence. This presents an opportunity to develop miR-181c and NOTCH2 as markers for early identification of high risk cases and the use of NOTCH inhibitors in the prevention or treatment of recurrent disease.

NFE2L2/NRF2 Activity Is Linked to Mitochondria and AMP-Activated Protein Kinase Signaling in Cancers Through miR-181c/Mitochondria-Encoded Cytochrome c Oxidase Regulation

AIMS

The nuclear factor (erythroid-derived 2)-like 2 (NFE2L2; NFE2L2/NRF2) pathway contributes to the environmental resistance of cancers by enhancing the antioxidant capacity. Here, we explored the potential connection between NFE2L2/NRF2 and mitochondrial function in cancers.

RESULTS

Global miRNA expression analysis of HT29 and HCT116 human colon cancer cells identified that NFE2L2/NRF2 silencing upregulated miR-181c through nuclear factor-κB signaling, and this increase was associated with the reduction in mitochondria-encoded cytochrome c oxidase subunit-1 (MT-CO1), a catalytic core subunit of the complex IV of the electron transport chain (ETC). As a result of ETC dysfunction, NFE2L2/NRF2-silenced cancer cells exhibited the decreases in the mitochondrial membrane potential, oxygen consumption rate, and cellular adenosine triphosphate (ATP) contents. Notably, these changes induced adenosine monophosphate (AMP)-activated protein kinase-α (AMPKα) activation and subsequent metabolic adaptation signaling, including the inhibition of fatty acid and sterol biosynthesis enzymes. As supportive evidence of AMPKα-driven adaption, NFE2L2/NRF2-silenced cells were more vulnerable to AMPKα inhibition-induced growth suppression. Similarly, mouse tumor xenografts derived from NFE2L2/NRF2-silenced HT29 exhibited MT-CO1 reduction and AMPKα activation, thereby increasing responsiveness to the AMPK inhibitor treatment. The association of NFE2L2/NRF2 with MT-CO1 and AMPKα was confirmed in breast cancer cells.

INNOVATION

We demonstrated the significance of NFE2L2/NRF2 in cancer mitochondria by elucidating the involvement of miR-181c/MT-CO1 as underlying molecular events. We also provide evidence of the crosstalk between NFE2L2/NRF2 and AMPKα as an adaptive link in cancers.

CONCLUSION

Therefore, it may be an effective strategy to inhibit both NFE2L2/NRF2 and AMPKα signaling to overcome adaptive behaviors of cancer. Antioxid. Redox Signal. 27, 945-961.

miR-181c protects CsA-induced renal damage and fibrosis through inhibiting EMT

Cyclosporine A (CsA), a widely used immunosuppressive drug in organ transplantation and autoimmune disorders, frequently induces renal damage and fibrosis. Recent evidence has implicated epithelial-mesenchymal transition (EMT) in CsA-induced nephrotoxicity. Microarray analysis disclosed miR-181c as the microRNA most dramatically repressed by CsA. Downregulation of miR-181c expression at the transcriptional level by CsA is dependent on the transcription factor Nrf2. miR-181c mimics or inhibitors attenuate or aggravate CsA-induced EMT gene changes, respectively. Importantly, in Nrf2-/- mice, CsA-induced renal damage, fibrosis, and EMT gene changes are restored by miR-181c mimics. Mechanistically, we identified Notch2 as a potential target of miR-181c. Collectively, our data support the notion that miR-181c may serve as an important factor for protecting renal tissues from CsA-induced nephrotoxicity.

MicroRNA-181c inhibits cigarette smoke-induced chronic obstructive pulmonary disease by regulating CCN1 expression

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is an obstinate pulmonary disease, causing irreversible alveoli collapse and increasing the risk for cardiovascular disease. Accumulating evidence has shown that the dysregulation of miRNAs is crucially involved in the pathogenesis and development of COPD. However, the effects and role of microRNA-181c (miR-181c) have not been investigated in a murine model of COPD.

METHODS

miR-181c expression was detected in human lung tissue samples of 34 patients, an in vivo murine model of CS exposure, and primary human bronchial epithelial cells (HBECs) by qRT-PCR. Degeneration of lung tissue, necrosis, infiltration and neutrophil cells were assessed with H&E and flow cytometry. Interleukin (IL)-6 and IL-8 levels were determined by an enzyme-linked immunosorbent assay and qRT-PCR. Luciferase reporter assay and correlation analyses were used to confirm and measure the levels between miR-181c and its target CCN1.

RESULTS

We showed that miR-181c was significantly down-regulated in lung tissues from patients with COPD compared to individuals who had never smoked (p < 0.01). We also observed a down-regulation of miR-181c in HBECs and a mouse model after cigarette smoke (CS) exposure. Functional assays demonstrated that miR-181c over-expression decreased the inflammatory response, neutrophil infiltration, reactive oxygen species (ROS) generation, and inflammatory cytokines induced by CS, while its down-regulation produced the opposite effects. Subsequent investigation found that CCN1 was a direct target of miR-181c. CCN1 expression was increased in lung tissues of COPD patients, and was negatively correlated with miR-181c expression in human COPD samples (p < 0.01).

CONCLUSIONS

Taken together, our data suggest the critical roles of miR-181c and its target CCN1 in COPD development, and provide potential therapeutic targets for COPD treatment.

NEAT1/miR-181c Regulates Osteopontin (OPN)-Mediated Synoviocyte Proliferation in Osteoarthritis

Osteoarthritis (OA) is characterized by progressive destruction of articular cartilage, resulting in significant disability. Inflammatory cytokines commonly initiate the extreme changes in the synovium and cartilage microenvironment of the OA patients, subsequently resulting in cell dysfunctions, especially synoviocyte dysfunction. We revealed that the expression of osteopontin (OPN), which has been reported to regulate expression of various inflammatory factors associating with the pathogenesis of OA including matrix metalloprotease 13 (MMP13), interlukine-6 and 8 (IL-6 and IL-8), is significantly upregulated in OA tissues. In the present study, online tools were used to screen out the candidate miRNAs of OPN. Among the candidate miRNAs, miR-181c inhibited OPN mRNA expression the most strongly. Ectopic expression of miR-181c significantly repressed synoviocyte proliferation, as well as the levels of OPN, MMP13, IL-6, and IL-8. Further, the candidate lncRNAs of miR-181c were screened out by using DianaTools; among which NEAT1 showed to inversely regulate miR-181c. By performing Luciferase assays, we revealed that NEAT1 competed with OPN for miR-181c binding. After NEAT1 knockdown, MMP13, IL-6, and IL-8 expression was reduced; the synoviocyte proliferation was repressed, as well as OPN protein levels; the suppressive effect of NETA1 knockdown on synoviocyte proliferation and the indicated factors were partially reversed by miR-181c inhibition. In OA tissues, OPN mRNA, and NEAT1 expression was upregulated, whereas miR-181c expression was downregulated, indicating that targeting NEAT1 to rescue miR-181c expression so as to inhibit OPN expression and synoviocyte proliferation might be an efficient strategy for OA treatment. J. Cell. Biochem. 118: 3775-3784, 2017. © 2017 Wiley Periodicals, Inc.

Upregulation of miR-181c contributes to chemoresistance in pancreatic cancer by inactivating the Hippo signaling pathway

The Hippo signaling pathway plays a crucial role in regulating tissue homeostasis, organ size, tumorigenesis and cancer chemoresistance when deregulated. Physiologically, the Hippo core kinase cassette that consists of mamma-lian STE20-like protein kinase 1/2 (MST1/2), and large tumour suppressor 1/2 (LATS1/2), together with the adaptor proteins Salvador homologue 1 (SAV1) and MOB kinase activator 1 (MOB1), tightly restricts the activities of homologous oncoproteins Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) to low levels. However, how the Hippo kinase cassette core components are simultaneously inhibited, to exhibit constitutively inactivated Hippo signaling and activated YAP/TAZ in cancer remains puzzling. Herein, we reported that miR-181c directly repressed MST1, LATS2, MOB1 and SAV1 expression in human pancreatic cancer cells. Overexpression of miR-181c induced hyperactivation of the YAP/TAZ and enhanced expression of the Hippo signaling downstream genes CTGF, BIRC5 and BLC2L1, leading to pancreatic cancer cell survival and chemoresistance in vitro and in vivo. Importantly, high miR-181c levels were significantly correlated with Hippo signaling inactivation in pancreatic cancer samples, and predicted a poor patient overall survival. These findings provide a novel mechanism for Hippo signaling inactivation in cancer, indicating not only a potentially pivotal role for miR-181c in the progression of pancreatic cancer, but also may represent a new therapeutic target and prognostic marker.

Exosome Derived From Human Umbilical Cord Mesenchymal Stem Cell Mediates MiR-181c Attenuating Burn-induced Excessive Inflammation

Mesenchymal stem cell (MSC)-derived exosomes have diverse functions in regulating wound healing and inflammation; however, the molecular mechanism of human umbilical cord MSC (hUCMSC)-derived exosomes in regulating burn-induced inflammation is not well understood. We found that burn injury significantly increased the inflammatory reaction of rats or macrophages exposed to lipopolysaccharide (LPS), increased tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) levels and decreased IL-10 levels. hUCMSC-exosome administration successfully reversed this reaction. Further studies showed that miR-181c in the exosomes played a pivotal role in regulating inflammation. Compared to control hUCMSC-exosomes, hUCMSC-exosomes overexpressing miR-181c more effectively suppressed the TLR4 signaling pathway and alleviated inflammation in burned rats. Administration of miR-181c-expressing hUCMSC-exosomes or TLR4 knockdown significantly reduced LPS-induced TLR4 expression by macrophages and the inflammatory reaction. In summary, miR-181c expression in hUCMSC-exosomes reduces burn-induced inflammation by downregulating the TLR4 signaling pathway.

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hUCMSC-exosome administration attenuated burn-induced inflammation

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miR-181c in hUCMSC-exosome served an pivotal role in regulating inflammation

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miR-181c repressed burn-induced inflammation via targeting TLR4

This study wants to address the potential function of exosomal miRNA on regulating burn-induced inflammation, and our results indicated that exosome derived from stem cells administration attenuated burn-induced inflammation of rats. Further study elucidated that miR-181c might serve an essential role in regulating inflammation. miR-181c suppressed toll-like receptor 4 expression, and subsequently reduced the expression of pro-inflammatory factors TNF-α, IL-1β. Forced expression of miR-181c in exosome further alleviated burn-induced inflammation. So our study provided a complete understanding of exosomal miR-181c in regulating burn-induced inflammation and its potentials as clinical therapeutic target of burn patients.

MiR181c inhibits ovarian cancer metastasis and progression by targeting PRKCD expression

MicroRNAs (miRNAs) regulate many important cancer related gene expression in the posttranscriptional process. Dysregulated expression of miRNAs has been observed in numerous human cancers including ovarian cancer. In this study, we found that the expression of the miR-181c was significantly decreased in ovarian cancer tissue and in tissues with lymph node metastasis when compared with their control samples, respectively. Moreover, among pathological stages, the expression of miR-181c was significantly decreased in the tissues with IV stage compared with other stages. In vitro, miR-181c significantly inhibited the proliferation, metastasis of A2780 cell line, and induced G1 phase arrest. Through bioinformatics prediction, protein kinase C delta (PRKCD) was identified as a target gene of miR-181c. Western blot results showed that PRKCD was increased in ovarian cancer tissue, in tissues with lymph node metastasis and IV stage of ovarian cancer pathological samples. After knocking down PRKCD, the cell cycle of A2780 cells was also arrested in G1 phase. The proliferation and the metastasis of A2780 cells were reduced. The dual luciferase reporter experiments showed that miR-181c regulated the expression of PRKCD by combining with its 3'UTR. These results indicate that miR-181c inhibits ovarian cancer metastasis and progression by targeting PRKCD expression.

MicroRNA-181c negatively regulates the inflammatory response in oxygen-glucose-deprived microglia by targeting Toll-like receptor 4

Cerebral hypoxia/ischemia rapidly induces inflammation in the brain, which is characterized by microglial activation and the release of inflammatory cytokines. We have previously demonstrated that miR-181c can directly regulate tumor necrosis factor (TNF)-α production post-transcriptionally. Here, we determined that hypoxia up-regulated TLR4 expression but down-regulated miR-181c expression in primary microglia. We also demonstrated that miR-181c suppresses TLR4 by directly binding its 3'-untranslated region. In addition, miR-181c inhibited NF-κB activation and the downstream production of proinflammatory mediators, such as TNF-α, IL-1β, and iNOS. Knocking down TLR4 in microglia significantly decreased TLR4 expression and inhibited NF-κB activation and the downstream production of proinflammatory mediators, whereas ectopic TLR4 expression significantly abrogated the suppressed inflammatory response induced by miR-181c. Therefore, our study identified an important role for the miR-181c-TLR4 pathway in hypoxic microglial activation and neuroinflammation. This pathway could represent a potential therapeutic target for cerebral hypoxic diseases associated with microglial activation and the inflammatory response. Cerebral hypoxia/ischemia induces microglial activation and the release of inflammatory cytokines. We found that hypoxia down-regulated miR-181c in primary microglia. In addition, miR-181c inhibited TLR4 expression through binding to its 3'UTR, thus inhibiting NF-kB activation and the production of downstream proinflammatory mediators. Therefore, the miR-181c-TLR4 pathway may be a potential therapeutic target for the treatment of cerebral hypoxic diseases.

MiR-181c modulates the proliferation, migration, and invasion of neuroblastoma cells by targeting Smad7

MicroRNAs (miRNAs) function as key regulators of gene expression in various cancers. In this study, the aim is to explore the roles and regulation mechanism of miR-181c in neuroblastoma (NB) cells. We found that miR-181c was downregulated in metastatic NB tissues, compared with primary NB tissues. Then functional studies indicated that miR-181c overexpression inhibited NB cell proliferation, migration, and invasion, while miR-181c inhibition increased cell proliferation, migration, and invasion. EGFP reporter assay, real-time polymerase chain reaction and western blot analysis validated that Smad7 was a direct target of miR-181c. MiR-181c reduced Smad7 expression at both mRNA and protein levels. Finally, functional assays showed that the effect of Smad7 knockdown on cells was similar to that of miR-181c overexpression. Importantly, Smad7 overexpression could restore the antitumor effects that were induced by miR-181c. In conclusion, our results demonstrated that miR-181c inhibits NB cell growth and metastasis-related traits through the suppression of Smad7, functioning as a tumor suppressor. Moreover, our results suggested that miR-181c may serve as an important therapeutic target for NB patients.

Roles of miR-1-1 and miR-181c in ventricular septal defects

BACKGROUND

MicroRNAs (miRNAs) are endogenous noncoding RNAs of approximately 22 nucleotides in length that mediate post-transcriptional gene silencing by annealing to sequences in the 3'-untranslated region of target mRNAs.

METHODS

In this study, we analyzed 25 candidate miRNAs selected based on microarray data for cardiac tissue from individuals with congenital heart defects (CHDs) and from healthy control tissue.

RESULTS

This study identified specific changes in the miR-1-1 and miR-181c levels in human cardiac samples from individuals with ventricular septal defects (VSDs) relative to the levels in healthy control tissue. Increased levels of GJA1 and SOX9 were associated with the decreased expression of miR-1-1 in VSD patients, and increased miR-181c expression was correlated with downregulated BMPR2 levels. In addition, the results revealed that miR-1-1 and miR-181c directly regulate the expression of these predicted targets.

CONCLUSIONS

miR-1-1 and miR-181c are associated with the pathogenesis of VSDs.