miR-421 promotes apoptosis and suppresses metastasis of osteosarcoma cells via targeting LTBP2

Increasing evidence has confirmed that microRNAs (miRs) are involved in tumor development and progression. A previous study reported that miR-421 could serve as a diagnostic marker in patients with osteosarcoma (OS). The present study explored the potential roles of miR-421 in the regulation of cell proliferation, apoptosis, migration, invasion, and epithelial-mesenchymal transition of OS cells. Our results showed that miR-421 was upregulated in OS tissues and cell lines (MG63, U2OS, HOS, and Saos-2) compared with the corresponding adjacent tissues or human osteoblast cells hFOB1.19, while the latent transforming growth factor β-binding protein 2 (LTBP2) expression was reduced. In MG63 and U2OS cells, CCK8 assay displayed that cell proliferation was repressed by the miR-421 inhibitor, conversely increased by miR-421 mimics. Inhibition of miR-421 promoted cell apoptosis rate, caspase 3 activity, cleaved-caspase 3 (c-caspase 3) expression, and Bax/Bcl-2 ratio, restoration of miR-421 showed the opposite functions. Suppression of miR-421 blocked migration and invasion, whereas miR-421 overexpression promoted the migration and invasion of MG63 and U2OS cells. In addition, real-time polymerase chain reaction and Western blot analysis revealed that miR-421 negatively regulated E-cadherin expression, and positively regulated the expression of N-cadherin and vimentin. The luciferase reporter assay determined that miR-421 could target LTBP2-3′-UTR, and LTBP2 expression was regulated negatively by miR-421 both in mRNA and protein levels. Depletion of LTBP2 partly abolished the biological functions of miR-421 inhibitor in OS. In conclusion, miR-421 plays an oncogenic role in OS via targeting LTBP2, suggesting that miR-421 may be a potential therapeutic target against OS.     

The expression of miR‐125b in Nrf2‐silenced A549 cells exposed to hyperoxia and its relationship with apoptosis

Bronchopulmonary dysplasia (BPD) is a chronic lung disease that affects the quality of life of infants. At present, premature exposure to hyperoxia for extended periods of time is believed to affect the development of lung tissue and vascularity, resulting in BPD. The oxidative stress caused by hyperoxia exposure is an important risk factor for BPD in premature infants. Nuclear factor E2‐related factor 2 (Nrf2) is an important regulator of antioxidant mechanisms. As a microRNA, microRNA‐125b (miR‐125b) plays an important role in cell proliferation, differentiation and apoptosis. Although the Nrf2/ARE pathway has been extensively studied, little is known about the regulatory role of microRNAs in Nrf2 expression. In this study, the expression levels of Nrf2 and miR‐125b in the lung tissues of premature Sprague Dawley (SD) rats and A549 cells exposed to hyperoxia were detected by quantitative real‐time polymerase chain reaction (qRT‐PCR), and the apoptosis of A549 cells was detected by flow cytometry. The results showed that Nrf2 and miRNA‐125b in the lung tissues of premature rats increased significantly upon exposure to hyperoxia and played a protective role. Nrf2 was suppressed by small interfering RNA (siRNA) in A549 cells, miR‐125b was similarly inhibited, and apoptosis was significantly increased. These results suggest that miR‐125b helps protect against BPD as a downstream target of Nrf2.     

Expression of transforming growth factor beta (TGF-b1) by human preterm lung inflammatory cells

Using a previously published model of human BPD this study examines whether preterm lung inflammatory cells produce transforming growth factor beta 1 (TGF-beta1), a cytokine pivotal in pathogenesis of bronchopulmonary dysplasia (BPD), and whether TGF-beta1 expression is regulated by inflammation. Lung inflammatory cells (neutrophils and macrophages) recovered in the broncho-alveolar (BAL) fluid of premature infants intubated for respiratory distress after birth expressed TGF-b1 mRNA and protein. Total and bioactive TGF-beta1 were abundantly found in the BAL fluid of the same infants. In cell culture stimulation by lipopolysaccharide (LPS) did not result in any further expression of total or bioactive TGF-beta1 by neonatal lung inflammatory cells over constitutive concentrations. In conclusion, lung inflammatory cells from premature infants are a source of TGF-beta1 but LPS does not regulate TGF-b1 production in these cells.     

Downregulation of human farnesoid X receptor by miR-421 promotes proliferation and migration of hepatocellular carcinoma cells

The farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily that is highly expressed in liver, kidney, adrenal gland, and intestine. It plays an important role in regulating the progression of several cancers including hepatocellular carcinoma (HCC). So it is necessary to study the regulation of FXR. In this study, we found that the expression of miR-421 was inversely correlated with FXR protein level in HCC cell lines. Treatment with miR-421 mimic repressed FXR translation. The reporter assay revealed that miR-421 targeted 3' untranslated region of human FXR mRNA. Furthermore, downregulation of FXR by miR-421 promoted the proliferation, migration, and invasion of HCC cells. These results suggest that miR-421 may serve as a novel molecular target for manipulating FXR expression in hepatocyte and for the treatment of HCC.     

The Axonal Guidance Cue Semaphorin 3C Contributes to Alveolar Growth and Repair

Lung diseases characterized by alveolar damage such as bronchopulmonary dysplasia (BPD) in premature infants and emphysema lack efficient treatments. Understanding the mechanisms contributing to normal and impaired alveolar growth and repair may identify new therapeutic targets for these lung diseases. Axonal guidance cues are molecules that guide the outgrowth of axons. Amongst these axonal guidance cues, members of the Semaphorin family, in particular Semaphorin 3C (Sema3C), contribute to early lung branching morphogenesis. The role of Sema3C during alveolar growth and repair is unknown. We hypothesized that Sema3C promotes alveolar development and repair. In vivo Sema3C knock down using intranasal siRNA during the postnatal stage of alveolar development in rats caused significant air space enlargement reminiscent of BPD. Sema3C knock down was associated with increased TLR3 expression and lung inflammatory cells influx. In a model of O₂-induced arrested alveolar growth in newborn rats mimicking BPD, air space enlargement was associated with decreased lung Sema3C mRNA expression. In vitro, Sema3C treatment preserved alveolar epithelial cell viability in hyperoxia and accelerated alveolar epithelial cell wound healing. Sema3C preserved lung microvascular endothelial cell vascular network formation in vitro under hyperoxic conditions. In vivo, Sema3C treatment of hyperoxic rats decreased lung neutrophil influx and preserved alveolar and lung vascular growth. Sema3C also preserved lung plexinA2 and Sema3C expression, alveolar epithelial cell proliferation and decreased lung apoptosis. In conclusion, the axonal guidance cue Sema3C promotes normal alveolar growth and may be worthwhile further investigating as a potential therapeutic target for lung repair.     

Methylation of miR-19b-3p promoter exacerbates inflammatory responses in sepsis-induced ALI via targeting KLF7

Sepsis-induced acute lung injury is associated with dysregulated inflammatory reactions. MiR-19b-3p level was reported to be downregulated in patients with sepsis. To evaluate the role of miR-19b-3p in sepsis, cecum ligation and puncture-induced mouse sepsis model and lpopolysaccharide (LPS)-treated pulmonary microvascular endothelial cells (PMVECs) were used. For in vivo study, lung tissue was harvested for hematoxylin and eosin (H&E) staining, tumor necrosis factor-α, interleukin-6 (IL-6), IL-1β, and p-p65, p-IκB measuring. Cell apoptosis was assessed by TUNEL assay. For in vitro study, cell proliferation and apoptosis were detected by CCK-8 and flow cytometry, respectively. Methylation of miR-19b-3p promoter was measured by methylation-specific PCR (MSP) assay. The target of miR-19b-3p was determined by dual-luciferase reporter gene assay. The level of miR-19b-3p was determined to be downregulated in vitro and in vivo. In addition, miR-19b-3p protected mice from inflammation injury through inhibiting NF-κB signaling pathway. Overexpression of miR-19b-3p increased cell viability, decreased apoptosis, and proinflammatory cytokines secretion in LPS-treated PMVECs. Besides these, Krüppel-like factor 7 (KLF7) was confirmed as the target of miR-19b-3p. And methylation of miR-19b-3p was the reason of decreased miR-19b-3p level. In conclusion, miR-19b-3p protected cells from sepsis-induced inflammation injury via inhibiting NF-κB signaling pathway, and KLF7 was a potential target.     

Fgf10 dosage is critical for the amplification of epithelial cell progenitors and for the formation of multiple mesenchymal lineages during lung development

The key role played by Fgf10 during early lung development is clearly illustrated in Fgf10 knockout mice, which exhibit lung agenesis. However, Fgf10 is continuously expressed throughout lung development suggesting extended as well as additional roles for FGF10 at later stages of lung organogenesis. We previously reported that the enhancer trap Mlcv1v-nLacZ-24 transgenic mouse strain functions as a reporter for Fgf10 expression and displays decreased endogenous Fgf10 expression. In this paper, we have generated an allelic series to determine the impact of Fgf10 dosage on lung development. We report that 80% of the newborn Fgf10 hypomorphic mice die within 24 h of birth due to respiratory failure. These mutant mouse lungs display severe hypoplasia, dilation of the distal airways and large hemorrhagic areas. Epithelial differentiation and proliferation studies indicate a specific decrease in TTF1 and SP-B expressing cells correlating with reduced epithelial cell proliferation and associated with a decrease in activation of the canonical Wnt signaling in the epithelium. Analysis of vascular development shows a reduction in PECAM expression at E14.5, which is associated with a simplification of the vascular tree at E18.5. We also show a decrease in α-SMA expression in the respiratory airway suggesting defective smooth muscle cell formation. At the molecular level, these defects are associated with decrease in Vegfa and Pdgfa expression likely resulting from the decrease of the epithelial/mesenchymal ratio in the Fgf10 hypomorphic lungs. Thus, our results indicate that FGF10 plays a pivotal role in maintaining epithelial progenitor cell proliferation as well as coordinating alveolar smooth muscle cell formation and vascular development.     

MicroRNA-192 targeting retinoblastoma 1 inhibits cell proliferation and induces cell apoptosis in lung cancer cells

microRNAs play an important roles in cell growth, differentiation, proliferation and apoptosis. They can function either as tumor suppressors or oncogenes. We found that the overexpression of miR-192 inhibited cell proliferation in A549, H460 and 95D cells, and inhibited tumorigenesis in a nude mouse model. Both caspase-7 and the PARP protein were activated by the overexpression of miR-192, thus suggesting that miR-192 induces cell apoptosis through the caspase pathway. Further studies showed that retinoblastoma 1 (RB1) is a direct target of miR-192. Over-expression of miR-192 decreased RB1 mRNA and protein levels and repressed RB1-3'-UTR reporter activity. Knockdown of RB1 using siRNA resulted in a similar cell morphology as that observed for overexpression of miR-192. Additionally, RB1-siRNA treatment inhibited cell proliferation and induced cell apoptosis in lung cancer cells. Analysis of miRNA expression in clinical samples showed that miR-192 is significantly downregulated in lung cancer tissues compared to adjacent non-cancerous lung tissues. In conclusion, our results demonstrate that miR-192 is a tumor suppressor that can target the RB1 gene to inhibit cell proliferation and induce cell apoptosis in lung cancer cells. Furthermore, miR-192 was expressed at low levels in lung cancer samples, indicating that it might be a promising therapeutic target for lung cancer treatment.     

microRNA-383 regulates cell viability and apoptosis by mediating Wnt/β-catenin signaling pathway in non–small cell lung cancer

The aim of this study was to investigate the roles of microRNA-383 (miRNA-383) in progression of non–small cell lung cancer (NSCLC) and the potential mechanism. The expressions of miR-383 and Wnt1 protein were detected in lung cancer tissues and cells by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis. After the transfection of miR-383 mimics, si-Wnt1 or miR-383+Wnt1, the viability and apoptosis of NSCLC cells were detected by cell counting kit-8 and terminal deoxynucleotidyl transferase–mediated dUTP nick-end labeling, respectively. The interaction between miR-383 and Wnt1 was investigated by luciferase activity and Western blot analysis. Cells stably transfected with miR-383 mimics were inoculated into the right axillary of nude mice by subcutaneous injection. The tumor volume and weight were measured, and the expressions of miR-383, Wnt1, β-catenin, and cyclin D1 were detected by qRT-PCR and Western blot analysis. The expression of miR-383 was significantly decreased, and the level of Wnt1 was significantly increased (P < 0.05) in lung cancer tissues and cells. Upregulation of miR-383 or inhibition of Wnt1 expression inhibited the cell viability and induce apoptosis in NSCLC cells. Moreover, Wnt1 was the target gene of miR-383, and its overexpression weakened the regulatory effect of miR-383 on cell viability and apoptosis in NSCLC cells. Besides, the addition of miR-383 decreased the tumor volume and size and inhibited the expressions of Wnt1, β-catenin, and cyclin D1 at the protein level in nude mice. Collectively, miR-383 induced apoptosis and inhibited cell viability as well as tumorigenic capacity in nude mice via regulating the Wnt/β-catenin signaling pathway.     

MiR-143 is not essential for adipose development as revealed by in vivo antisense targeting

MiR-143 plays an important role in promoting the adipogenic differentiation of pre-adipocytes. Here, we report that systematic silencing of miR-143 in mice by using a locked-nucleic-acid-modified oligonucleotide (LNA-antimiR) did not lead to any obvious abnormalities in the adipose tissue differentiation. Furthermore, there were no significant differences in the expression level of several adipogenic marker genes, such as PPARγ and C/EBPα, in these animals compared with the controls. Therefore, we hypothesize that miR-143 may function as a fine tuning molecule rather than as a switch in the adipogenic regulatory network in mice. In addition, the proposed miR-143 target, ERK5, which was previously identified in human preadipocytes, was not effectively inhibited by miR-143 either in the murine preadipocyte cell line, 3T3-L1, or in primary mouse adipose tissue. However, we did fibroblast growth factor 7 (Fgf7) was identified as a target of miR-143 in murine adipogenesis.     

A transcriptional target of androgen receptor,miR-421 regulates proliferation and metabolism of prostate cancer cells

Prostate cancer is one of the most common malignancies, and microRNAs have been recognized to be involved in tumorigenesis of various kinds of cancer including prostate cancer (PCa). Androgen receptor (AR) plays a core role in prostate cancer progression and is responsible for regulation of numerous downstream targets including microRNAs. This study identified an AR-repressed microRNA, miR-421, in prostate cancer. Expression of miR-421 was significantly suppressed by androgen treatment, and correlated to AR expression in different prostate cancer cell lines. Furthermore, androgen-activated AR could directly bind to androgen responsive element (ARE) of miR-421, as predicted by bioinformatics resources and demonstrated by ChIP and luciferase reporter assays. In addition, over-expression of miR-421 markedly supressed cell viability, delayed cell cycle, reduced glycolysis and inhibited migration in prostate cancer cells. According to the result of miR-421 target genes searching, we focused on 4 genes NRAS, PRAME, CUL4B and PFKFB2 based on their involvement in cell proliferation, cell cycle progression and metabolism. The expression of these 4 downstream targets were significantly repressed by miR-421, and the binding sites were verified by luciferase assay. Additionally, we explored the expression of miR-421 and its target genes in human prostate cancer tissues, both in shared microarray data and in our own cohort. Significant differential expression and inverse correlation were found in PCa patients.     

Retracted: Long noncoding LINC01551 promotes hepatocellular carcinoma cell proliferation,migration, and invasion by acting as a competing endogenous RNA of microRNA-122-5p to regulate ADAM10 expression

Hepatocellular carcinoma (HCC) is a severe disease with high mortality in the world. It has been shown that long noncoding RNA (lncRNA) might play a role in HCC. The aim of the present study was to identify the role of long intergenic noncoding RNA 01551 (LINC01551) in the HCC development and explore the underlying mechanism of LINC01551/miR-122-5p/ADAM10 axis. The differentially expressed lncRNAs associated with HCC were screened out by a microarray analysis. The expression of LINC01551, miR-122-5p, and ADAM10 was determined in HCC tissues and cells. The potential miRNA (miR-122-5p) regulated by LINC01551 was explored, and the target relationship between miR-122-5p and ADAM10 was confirmed. To evaluate the effect of LINC01551 and miR-122-5p on proliferation, migration, invasion, and apoptosis of HCC, different plasmids were delivered into MHCC97-H cells. High expression of LINC01551 and ADAM10 yet low-expression of miR-122-5p were revealed in HCC tissues and cells. Overexpression of miR-122-5p could downregulate ADAM10. Biological prediction websites and fluorescence in situ hybridization assay verified that LINC01551 was mainly expressed in the cytoplasm. Silencing LINC01551 reduced HCC cell viability, proliferation, migration, invasion, and cell cycle entry yet induce cell apoptosis. Upregulation of LINC01551 increased its ability of competitively binding to miR-122-5p, thus reducing miR-122-5p and upregulating ADAM10 expression, as well as promoting the proliferative, migrative, and invasive ability. Taken together the results, it is highly possible that LINC01551 functions as an competing endogenous RNA (ceRNA) to regulate the miRNA target ADAM10 by sponging miR-122-5p and therefore promotes the development of HCC, highlighting a promising competitive new target for the HCC treatment.     

Conditional overexpression of TGFβ1 promotes pulmonary inflammation,apoptosis and mortality via TGFβR2 in the developing mouse lung

Background

Earlier studies have reported that transforming growth factor beta 1(TGFβ1) is a critical mediator of hyperoxia-induced acute lung injury (HALI) in developing lungs, leading to impaired alveolarization and a pulmonary phenotype of bronchopulmonary dysplasia (BPD). However, the mechanisms responsible for the TGFβ1-induced inflammatory signals that lead to cell death and abnormal alveolarization are poorly understood. We hypothesized that TGFβ1 signaling via TGFβR2 is necessary for the pathogenesis of the BPD pulmonary phenotype resulting from HALI.

Methods

We utilized lung epithelial cell-specific TGFβ1 overexpressing transgenic and TGFβR2 null mutant mice to evaluate the effects on neonatal mortality as well as pulmonary inflammation and apoptosis in developing lungs. Lung morphometry was performed to determine the impaired alveolarization and multicolor flow cytometry studies were performed to detect inflammatory macrophages and monocytes in lungs. Apoptotic cell death was measured with TUNEL assay, immunohistochemistry and western blotting and protein expression of angiogenic mediators were also analyzed.

Results

Our data reveals that increased TGFβ1 expression in newborn mice lungs leads to increased mortality, macrophage and immature monocyte infiltration, apoptotic cell death specifically in Type II alveolar epithelial cells (AECs), impaired alveolarization, and dysregulated angiogenic molecular markers.

Conclusions

Our study has demonstrated the potential role of inhibition of TGFβ1 signaling via TGFβR2 for improved survival, reduced inflammation and apoptosis that may provide insights for the development of potential therapeutic strategies targeted against HALI and BPD.     

Epidermal growth factor-like domain 7 protects endothelial cells from hyperoxia-induced cell death

Hyperoxia is one of the major contributors to the development of bronchopulmonary dysplasia (BPD), a chronic lung disease in premature infants. Emerging evidence suggests that the arrested lung development of BPD is associated with pulmonary endothelial cell death and vascular dysfunction resulting from hyperoxia-induced lung injury. A better understanding of the mechanism of hyperoxia-induced endothelial cell death will provide critical information for the pathogenesis and therapeutic development of BPD. Epidermal growth factor-like domain 7 (EGFL7) is a protein secreted from endothelial cells. It plays an important role in vascular tubulogenesis. In the present study, we found that Egfl7 gene expression was significantly decreased in the neonatal rat lungs after hyperoxic exposure. The Egfl7 expression was returned to near normal level 2 wk after discounting oxygen exposure during recovery period. In cultured human endothelial cells, hyperoxia also significantly reduced Egfl7 expression. These observations suggest that diminished levels of Egfl7 expression might be associated with hyperoxia-induced endothelial cell death and lung injury. When we overexpressed human Egfl7 (hEgfl7) in EA.hy926 human endothelial cell line, we found that hEgfl7 overexpression could partially block cytochrome c release from mitochondria and decrease caspase-3 activation. Further Western blotting analyses showed that hEgfl7 overexpression could reduce expression of a proapoptotic protein, Bax, and increase expression of an antiapoptotic protein, Bcl-xL. Theses findings indicate that hEGFL7 may protect endothelial cell from hyperoxia-induced apoptosis by inhibition of mitochondria-dependent apoptosis pathway.     

MicroRNA-190 alleviates neuronal damage and inhibits neuroinflammation via Nlrp3 in MPTP-induced Parkinson's disease mouse model

Parkinson's disease (PD) is neurodegenerative dyskinesia characterized by loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Although neuroinflammation is one of the pathological features of PD, its mechanism of promoting PD is still not fully understood. Recently, the microRNA (miR) is considered to play a critical regulatory role in inflammatory responses. In this study, we examined the anti-inflammatory activity, antineuronal injury, and the underlying target of miR-190 with MPTP-induced PD mouse model and BV2 cells. The results showed that miR-190 is downregulated in lipopolysaccharide (LPS)-induced BV2 cells; however, when the miR-190 overexpressed, the expression of proinflammatory mediators, such as iNOS, IL-6, TNF-α, and TGF-β1, were inhibited and the anti-inflammatory mediator such IL-10 was increased. In addition, we predicted the potential target of miR-190 to be Nlrp3 and verified by luciferase reporter assay. The results also showed that Nlrp3 was upregulated in LPS-induced BV2 cells, whereas knockdown of Nlrp3 inhibited the LPS-induced inflammatory response in BV2 cells. Furthermore, upregulation of miR-190 or knockdown of Nlrp3 inhibited LPS-induced apoptosis in BV2 cells. However, the apoptosis inhibition effect of miR-190 was abrogated by overexpression of Nlrp3. Finally, upregulation of miR-190 inhibited the activation of microglial cells and inflammation and attenuated the tyrosine hydroxylase loss in SNpc in MPTP-induced PD mice. In conclusion, we demonstrated that miR-190 alleviates neuronal damage and inhibits inflammation via negatively regulating the expression and activation of Nlrp3 in MPTP-induced PD mouse model.     

MicroRNA-2861 and microRNA-5115 regulates myocardial ischemia–reperfusion injury through the GPR30/mTOR signaling pathway by binding to GPR30

Myocardial ischemia–reperfusion (I/R) injury, a major contributor to morbidity and mortality, represents a combination of intrinsic cellular response to ischemia and the extrinsic acute inflammatory response. In the present study, microarray analysis of GSE67308 and GSE50885 identified differentially expressed GPR30 and upstream regulatory miR-2861 and miR-5115 in myocardial I/R. Furthermore, GPR30 was confirmed as a common target gene of miR-2861 and miR-5115, and miR-2861 and miR-5115 inhibited GPR30 expression. Poor expression of GPR30 was identified in the myocardial I/R injury mouse model. Overexpressed GPR30 led to alleviated the pathological conditions, diminished myocardial infarct size and apoptosis of myocardial tissue in mice. Moreover, miR-2861 and miR-5115 were found to be highly expressed in the myocardial I/R injury mouse model and to subsequently accelerate the disease progression. Notably, PR30 curtailed the development of myocardial I/R injury through activation of the mTOR signaling pathway. The key findings suggested that miR-2861 and miR-5115 blocked the activation of the GPR30/mTOR signaling pathway by targeting GPR30, thereby accelerating myocardial I/R injury in mice.