Shu-Yang Xie

Alterations of Serum Levels of BDNF-Related miRNAs in Patients with Depression

Depression is a serious and potentially life-threatening mental disorder with unknown etiology. Emerging evidence shows that brain-derived neurotrophic factor (BDNF) and microRNAs (miRNAs) play critical roles in the etiology of depression. Here this study was aimed to identify and characterize the roles of BDNF and its putative regulatory miRNAs in depression. First, we identified that miR-182 may be a putative miRNA that regulates BDNF levels by bioinformatic studies, and characterized the effects of miR-182 on the BDNF levels using cell-based studies, side by side with miR-132 (a known miRNA that regulates BDNF expression). We showed that treatment of miR-132 and miR-182 respectively decreased the BDNF protein levels in a human neuronal cell model, supporting the regulatory roles of miR-132 and miR-182 on the BDNF expression. Furthermore, we explored the roles of miR-132 and miR-182 on the BDNF levels in depression using human subjects by assessing their serum levels. Compared with the healthy controls, patients with depression showed lower serum BDNF levels (via the enzyme-linked immunosorbent assays) and higher serum miR-132 and miR-182 levels (via the real-time PCR). Finally, the Pearson’s (or Spearman’s) correlation coefficient was calculated to study whether there was a relationship among the Self-Rating Depression Scale score, the serum BDNF levels, and serum BDNF-related miRNA levels. Our results revealed that there was a significant negative correlation between the SDS scores and the serum BDNF levels, and a positive correlation between the SDS scores and miR-132 levels. In addition, we found a reverse relationship between the serum BDNF levels and the miR-132/miR-182 levels in depression. Collectively, we provided evidence supporting that miR-182 is a putative BDNF-regulatory miRNA, and suggested that the serum BDNF and its related miRNAs may be utilized as important biomarkers in the diagnosis or as therapeutic targets of depression.

Higher intake of fruits, vegetables or their fiber reduces the risk of type 2 diabetes: A meta‐analysis

Some previous studies reported no significant association of consuming fruit or vegetables, or fruit and vegetables combined, with type 2 diabetes. Others reported that only a greater intake of green leafy vegetables reduced the risk of type 2 diabetes. To further investigate the relationship between them, we carried out a meta‐analysis to estimate the independent effects of the intake of fruit, vegetables and fiber on the risk of type 2 diabetes.

All-transretinoic acid ameliorates bleomycin-induced lung fibrosis by downregulating the TGF-β1/Smad3 signaling pathway in rats.

The transforming growth factor-β1 (TGF-β1)/Smad3 signaling pathway has a central role in pathogenesis of lung fibrosis. In the present study, we investigated if all-trans retinoic acid (ATRA) could attenuate fibrosis in bleomycin (BLM)-induced lung fibrosis in rats through regulating TGF-β1/Smad3 signaling. Beginning on day 14 after BLM administration, the ATRA I and II groups of rats received daily oral administration of ATRA for 14 days. All rats were killed on day 28. Lung tissue sections were prepared and subject to histological assessment, and expression levels of proteins involved in the TGF-β1 signaling cascade and epithelial–mesenchymal transition (EMT) were evaluated by transmission electron microscopy (TEM), quantitative real-time polymerase chain reaction (qRT-PCR), western blot procedure, and immunohistochemical or immunofluorescence staining. BLM significantly increased the alveolar septum infiltrates, inflammatory cell infiltrates, and collagen fibers. These BLM-induced changes were significantly ameliorated by ATRA treatment. In addition, BLM significantly increased levels of lung fibrosis markers α-SMA, hydroxyproline (Hyp), collagen I, Snail, and Twist, whereas significantly decreased E-cadherin expression. ATRA treatment largely reversed BLM-induced changes in these lung fibrosis markers. ATRA also blocked BLM-induced activation of the TGF-β1/Smad3 signaling pathway in lung tissues, including expression of TGF-β1, Smad3, p-Smad3, zinc-finger E-box-binding homeobox 1 and 2 (ZEB1 and ZEB2), and the high-mobility group AT-hook 2 (HMGA2). Our results suggest that ATRA may have potential therapeutic value for lung fibrosis treatment.

Low-dose paclitaxel ameliorates pulmonary fibrosis by suppressing TGF-β1/Smad3 pathway via miR-140 upregulation.

Abnormal TGF-β1/Smad3 activation plays an important role in the pathogenesis of pulmonary fibrosis, which can be prevented by paclitaxel (PTX). This study aimed to investigate an antifibrotic effect of the low-dose PTX (10 to 50 nM in vitro, and 0.6 mg/kg in vivo). PTX treatment resulted in phenotype reversion of epithelial-mesenchymal transition (EMT) in alveolar epithelial cells (AECs) with increase of miR-140. PTX resulted in an amelioration of bleomycin (BLM)-induced pulmonary fibrosis in rats with reduction of the wet lung weight to body weight ratios and the collagen deposition. Our results further demonstrated that PTX inhibited the effect of TGF-β1 on regulating the expression of Smad3 and phosphorylated Smad3 (p-Smad3), and restored the levels of E-cadherin, vimentin and α-SMA. Moreover, lower miR-140 levels were found in idiopathic pulmonary fibrosis (IPF) patients, TGF-β1-treated AECs and BLM-instilled rat lungs. Through decreasing Smad3/p-Smad3 expression and upregulating miR-140, PTX treatment could significantly reverse the EMT of AECs and prevent pulmonary fibrosis of rats. The action of PTX to ameliorate TGF-β1-induced EMT was promoted by miR-140, which increased E-cadherin levels and reduced the expression of vimentin, Smad3 and p-Smad3. Collectively, our results demonstrate that low-dose PTX prevents pulmonary fibrosis by suppressing the TGF-β1/Smad3 pathway via upregulating miR-140.

miR-511 induces the apoptosis of radioresistant lung adenocarcinoma cells by triggering BAX

Radioresistance is one of the main reasons for the failure of radiotherapy in lung cancer. The present study was conducted to identify the role of miR-511 in suppressing the growth of radioresistant lung adenocarcinoma cells. First, a radioresistant A549/R cell line was generated after prolonged exposure to X-rays for 68 Gy (2 Gy/day, 5 days/week) and the radioresistance was confirmed by wound healing assay. Next, oncogenic TRIB2 was found to be upregulated in the radioresistant A549/R cells when compared to that of the control A549 cells as determined by western blot analysis. As the upstream miRNA, quantitative PCR showed that miR-511 expression was decreased in the radioresistant A549/R cells. Overexpression of miR-511 in miR-511-transfected A549/R cells inhibited cell growth and increased the number of apoptotic cells when compared with the control treatment. Flow cytometric analysis further demonstrated that the growth suppressive effect of miR-511 on A549/R cells was mediated by regulation of the cell cycle, most likely due to a block in the G1-S transition. Finally, our results showed that the expression of BAX was lower in the radioresistant A549/R cells when compared with that in the control A549 cells. After downregulation of TRIB2 by miR-511 treatment, BAX expression was obviously increased in the miR-511-transfected apoptotic A549/R cells when compared to that in the NC-treated or control cultures. In summary, our results revealed that miR-511 regulates the growth of radioresistant A549/R cells by increasing BAX expression through TRIB2, which suggests that miR-511 may be a potential therapeutic molecule for the treatment of radioresistant lung adenocarcinoma.

Let-7c inhibits A549 cell proliferation through oncogenic TRIB2 related factors

MicroRNAs have tumor suppressive or oncogenic roles in carcinogenesis. This study aimed to investigate the mechanism of let‐7c in suppressing lung cancer cell proliferation. First, let‐7c was revealed to be able to inhibit lung adenocarcinoma cell proliferation significantly. TRIB2 was further demonstrated to be a novel target and negatively regulated by let‐7c. As downstream signals of TRIB2, the activities of C/EBP‐α and phosphorylated p38MAPK were increased obviously in let‐7c‐treated cells compared with controls. Our results demonstrate that, through regulating the expression of TRIB2 and its downstream factors, let‐7c can effectively inhibit A549 cell proliferation in vitro and in vivo.

The associations of single nucleotide polymorphisms in miR-146a, miR-196a and miR-499 with breast cancer susceptibility.

Background Previous studies have investigated the association between single nucleotide polymorphisms (SNPs) located in microRNAs (miRNAs) and breast cancer susceptibility; however, because of their limited statistical power, many discrepancies are revealed in these studies. The meta-analysis presented here aimed to identify and characterize the roles of miRNA SNPs in breast cancer risk, and evaluate the associations of polymorphisms in miR-146a rs2910164, miR-196a rs11614913 and miR-499 rs3746444 with breast cancer susceptibility, respectively. Methodology/Principal Findings The PubMed and Embases databases were searched updated to 31st December, 2012. The complete data of polymorphisms in miR-146a rs2910164, miR-196a rs11614913 and miR-499 rs3746444 from case-control studies for breast cancer were analyzed by odds ratios (ORs) with 95% confidence intervals (CIs) to reveal the associations of SNPs in miRNAs with breast cancer susceptibility. Totally, six studies for rs2910164 in miR-146a, involving 4225 cases and 4469 controls; eight studies for rs11614913 in miR-196a, involving 4110 cases and 5100 controls; and three studies of rs3746444 in miR-499, involving 2588 cases and 3260 controls, were investigated in the meta-analysis. The rs11614913 (TT+CT) genotype of miR-196a2 was revealed to be associated with a decreased breast cancer susceptibility compared with the CC genotypes (OR = 0.906, 95% CI: 0.825–0.995, P = 0.039); however, no significant associations were observed between rs2910164 in miR-146a (or rs3746444 in miR-499) and breast cancer susceptibility. Conclusions This meta-analysis demonstrates the compelling evidence that the rs11614913 CC genotype in miR-196a2 increases breast cancer risk, which provides useful information for the early diagnosis and prevention of breast cancer.

High glucose concentration induces endothelial cell proliferation by regulating cyclin-D2-related miR-98.

Cyclin D2 is involved in the pathology of vascular complications of type 2 diabetes mellitus (T2DM). This study investigated the role of cyclin‐D2‐regulated miRNAs in endothelial cell proliferation of T2DM. Results showed that higher glucose concentration (4.5 g/l) significantly promoted the proliferation of rat aortic endothelial cells (RAOECs), and significantly increased the expression of cyclin D2 and phosphorylation of retinoblastoma 1 (p‐RB1) in RAOECs compared with those under low glucose concentration. The cyclin D2‐3′ untranslated region is targeted by miR‐98, as demonstrated by miRNA analysis software. Western blot also confirmed that cyclin D2 and p‐RB1 expression was regulated by miR‐98. The results indicated that miR‐98 treatment can induce RAOEC apoptosis. The suppression of RAOEC growth by miR‐98 might be related to regulation of Bcl‐2, Bax and Caspase 9 expression. Furthermore, the expression levels of miR‐98 decreased in 4.5 g/l glucose‐treated cells compared with those treated by low glucose concentration. Similarly, the expression of miR‐98 significantly decreased in aortas of established streptozotocin (STZ)‐induced diabetic rat model compared with that in control rats; but cyclin D2 and p‐RB1 levels remarkably increased in aortas of STZ‐induced diabetic rats compared with those in healthy control rats. In conclusion, this study demonstrated that high glucose concentration induces cyclin D2 up‐regulation and miR‐98 down‐regulation in the RAOECs. By regulating cyclin D2, miR‐98 can inhibit human endothelial cell growth, thereby providing novel therapeutic targets for vascular complication of T2DM.

MiR-320a effectively suppresses lung adenocarcinoma cell proliferation and metastasis by regulating STAT3 signals.

ABSTRACT MicroRNAs play important roles in tumorigenesis of various types of cancers. MiR-320a can inhibits cell proliferation of some cancers, but the biologic roles of miR-320a in lung cancer need to be further studied. Here, we investigated the roles of miR-320a in suppressing the proliferation of lung adenocarcinoma cells. MiR-320a treatment was found to effectively suppress LTEP-a-2 and A549 cell proliferation, and induce more apoptotic cells with irradiation treatment compared with control treatment. Our results also showed that miR-320a, as a novel miRNA, directly regulated signal transducer and activator of transcription 3 (STAT3) and its signals, such as Bcl−2, Bax, and Caspase 3. The siRNA-inhibited STAT3 levels further proved its roles in regulating STAT3 signals. Moreover, miR-320a treatment effectively suppressed cancer cell growth in mice xenografts compared with controls, and significantly inhibited cell migration in vitro and in vivo. Our findings collectively demonstrated that miR-320a, by directly regulating STAT3 signals, not only suppressed cell proliferation and metastasis, but also enhanced irradiation-induced apoptosis of adenocarcinomia cells.

Sulindac has strong antifibrotic effects by suppressing STAT3-related miR-21.

Pulmonary fibrosis (PF) is a disease with an unknown cause and a poor prognosis. In this study, we aimed to explore the pathogenesis of PF and the mechanism of sulindac in attenuating bleomycin (BLM)‐induced PF. The rat PF model was induced by BLM and verified through histological studies and hydroxyproline assay. The severity of BLM‐induced PF in rats and other effects, such as the extent of the wet lung to bw ratios, thickening of alveolar interval or collagen deposition, was obviously ameliorated in sulindac‐treated rat lungs compared with BLM‐induced lungs. Sulindac also reversed the epithelial mesenchymal transition (EMT) and inhibited the PF process by restoring the levels of E‐cadherin and α‐smooth muscle actin (SMA) in A549 cells. Our results further demonstrated that the above effects of sulindac might be related to regulating of interferon gamma (IFN‐γ) expression, which further affects signal transducers and activators of transcription 3 (STAT3) and phosphorylated STAT3 (p‐STAT3) levels. Moreover, higher miR‐21 levels with the decreased E‐cadherin and increased α‐SMA expressions were found in transforming growth factor‐β1‐treated A549 cells, which can be reversed by sulindac. Collectively, our results demonstrate that by decreasing IFN‐γ‐induced STAT3/p‐STAT3 expression to down‐regulate miR‐21, sulindac could significantly reverse EMT in A549 cells and prevent BLM‐induced PF.