Autophagy regulates bone loss via the RANKL/RANK/OPG axis in an experimental rat apical periodontitis model.

AIM: Autophagy is involved in human apical periodontitis (AP). However, it is not clear whether autophagy is protective or destructive in bone loss via the receptor activator of nuclear factor-κB ligand (RANKL)/RANK/osteoprotegerin (OPG) axis. This study aimed to investigate the involvement of autophagy via the RANKL/RANK/OPG axis during the development of AP in an experimental rat model. METHODOLOGY: Twenty-four female Sprague-Dawley rats were divided into control, experimental AP (EAP) + saline, and EAP + 3-methyladenine (An autophagy inhibitor, 3-MA) groups. The control group did not receive any treatment. The EAP + saline group and the EAP + 3-MA group received intraperitoneal injections of saline and 3-MA, respectively, starting 1 week after the pulp was exposed. Specimens were collected for microcomputed tomography (micro-CT) scanning, histological processing, and immunostaining to examine the expression of light chain 3 beta (LC3B), RANK, RANKL, and OPG. Data were analysed using one-way analysis of variance (p < .05). RESULTS: Micro-CT showed greater bone loss in the EAP + 3-MA group than in the EAP + saline group, indicated by an elevated trabecular space (Tb.Sp) (p < .05). Inflammatory cell infiltration was observed in the EAP + saline and EAP + 3-MA groups. Compared with EAP + saline group, the EAP + 3-MA group showed weaker expression of LC3B (p < .01) and OPG (p < .05), more intense expression of RANK (p < .01) and RANKL (p < .01), and a higher RANKL/OPG ratio (p < .05). CONCLUSION: Autophagy may exert a protective effect against AP by regulating the RANKL/RANK/OPG axis, thereby inhibiting excessive bone loss.

[Retracted] miR­218­5p inhibits the stem cell properties and invasive ability of the A2B5+CD133­ subgroup of human glioma stem cells.

Following the publication of this paper, it was drawn to the Editors' attention by a concerned reader that Fig. 5 on p. 874 contained a series of DAPI panels within the figure that looked unexpectedly similar in appearance, with the similarities also evident in the second and 'Merge' data columns; moreover, of especial note, the similarities in the 'DAPI' panels for the Blank control experiments shown in Fig. 5C and D only affected a partial section of the data. In addition, the 'blank' and 'miR­control' panels in Fig. 6A also appeared to contain overlapping data. Independently of the issues that were raised by the interested reader, the authors themselves requested that their paper be retracted on account of having identified some problems with the presentation of various of the figures, and no longer being able to access their original data. The Editor of Oncology Reports has agreed that this paper should be retracted from the Journal, and apologizes to the readership for any inconvenience caused. [Oncology Reports 35: 869­877, 2016; DOI: 10.3892/or.2015.4418].

MiR-181a-5p Alleviates the Inflammatory Response of PC12 Cells by Inhibiting High-Mobility Group Box-1 Protein Expression.

OBJECTIVE: Neuroinflammation triggers sequelae after spinal cord injury (SCI). Inhibition of inflammation promotes recovery after SCI. MicroRNAs regulate many pathophysiological processes, including inflammation. Any role for miR-181a-5p in the inflammatory response after SCI remains unclear. Thus, we evaluated the effects of miR-181a-5p on inflammation in PC12 cells and the underlying mechanism in play. METHODS: Quantitative reverse transcription-polymerase chain reaction was used to measure the levels of miR-181a-5p and high-mobility group box-1 protein (HMGB1) in SCI tissues. Cell-counting kit-8 assays were used to assess the viability of PC12 cells treated with lipopolysaccharide (LPS). Plasmids encoding MiR-181a-5p mimics, an miR-181a-5p inhibitor, or/and the HMGB1 were transfected into PC12 cells. Quantitative reverse transcription-polymerase chain reaction or/and Western blotting were performed to assess the expression of miR-181a-5p, HMGB1, and inflammatory factors in vitro. RESULTS: MiR-181a-5p expression decreased and HMGB1 expression increased in SCI tissues and LPS-induced PC12 cells. Upregulation of miR-181a-5p (via transfection) inhibited inflammation of, and HMGB1 expression by, LPS-induced PC12 cells. HMGB1 overexpression reversed the anti-inflammatory effects of miR-181a-5p. Dual-luciferase assays confirmed that HMGB1 was a direct target of miR-181a-5p. CONCLUSIONS: miR-181a-5p attenuated the inflammatory response of LPS-induced PC12 cells by directly inhibiting HMGB1; thus, miR-181a-5p may serve as a therapeutic target in SCI.

Identification of microRNAs associated with glioma diagnosis and prognosis.

The sensitivity and specificity of microRNAs (miRNAs) for diagnosing glioma are controversial. We therefore performed a meta-analysis to systematically identify glioma-associated miRNAs. We initially screened five miRNA microarray datasets to evaluate the differential expression of miRNAs between glioma and normal tissues. We next compared the expression of the miRNAs in different organs and tissues to assess the sensitivity and specificity of the differentially expressed miRNAs in the diagnosis of glioma. Finally, pathway analysis was performed using GeneGO. We identified 27 candidate miRNAs associated with glioma initiation, progression, and patient prognosis. Sensitivity and specificity analysis indicated miR-15a, miR-16, miR-21, miR-23a, and miR-9 were up-regulated, while miR-124 was down-regulated in glioma. Ten signaling pathways showed the strongest association with glioma development and progression: the p53 pathway feedback loops 2, Interleukin signaling pathway, Toll receptor signaling pathway, Parkinson's disease, Notch signaling pathway, Cadherin signaling pathway, Apoptosis signaling pathway, VEGF signaling pathway, Alzheimer disease-amyloid secretase pathway, and the FGF signaling pathway. Our results indicate that the integration of miRNA, gene, and protein expression data can yield valuable biomarkers for glioma diagnosis and treatment. Indeed, six of the miRNAs identified in this study may be useful diagnostic and prognostic biomarkers in glioma.

MiR-218-5p inhibits the stem cell properties and invasive ability of the A2B5⁺CD133⁻ subgroup of human glioma stem cells.

MicroRNAs (miRs) act as oncogenes or tumor-suppressor genes, and regulate the proliferation, apoptosis, invasion, differentiation, angiogenesis and behavior of glioma stem cells, which are important in glioma development and recurrence. The present study was performed to investigate the impact of miR-218-5p on stem cell properties and invasive ability of the A2B5+CD133- human glioma stem cell subgroup. qRT-PCR was used to detect miR-218-5p expression in non-cancerous brain and human glioma tissues, human glioma cell lines and human glioma stem cell lines. Lentivirus vectors encoding miR-218-5p and anti-miR-218-5p were constructed and stably transfected into A2B5+CD133- SHG-139s cells. Neurosphere formation Cell Counting Kit-8 (CCK-8) and Transwell assays, immunofluorescence and qRT-PCR analyses were used to explore the role of miR-218-5p in SHG-139s cells. qRT-PCR analysis showed that miR-218-5p expression was lower in human glioma tissues and cells than in non-cancerous brain tissues and normal human astrocyte cells, and lower in A2B5+CD133- (SHG-139s) cells than in CD133+ (SU2 and U87s) cells. The CCK-8 assay demonstrated that the growth curve was significantly inhibited in the miR-218-5p-SHG-139s cells compared to the miR-control, blank and anti-miR­218-5p groups. The neurosphere formation assay indicated that upregulation of miR­218-5p expression inhibited SHG-139s neurosphere formation. Immunofluorescence staining and qRT-PCR showed that miR-218-5p reduced stem cell marker (A2B5, nestin, PLAGL2, ALDH1 and Sox2) expression compared with the controls; however, immunofluorescence staining analysis showed that upregulation of miR-218-5p expression led to no difference in CD133 expression. miR­218-5p reduced SHG-139s cell invasiveness in the Transwell assay and reduced MMP9 expression as detected in qRT-PCR and immunofluorescence analyses. All differences were statistically significant. miR-218-5p expression was lower in human glioma tissues, cells and the A2B5+CD133- human glioma stem cell subgroup. miR-218-5p may be a tumor-suppressor gene in glioma that functions by upregulating miR-218-5p expression, which inhibits the stem cell properties and invasive properties of SHG-139s cells.

miR-132 can inhibit glioma cells invasion and migration by target MMP16 in vitro.

Gliomas are the most common malignant primary brain tumors, and new clinical biomarkers and therapeutic targets are imminently required. MicroRNAs (miRNAs) are a novel class of small non-coding RNAs (∼22nt) involved in the regulation of various biological processes. Here, by using real-time polymerase chain reaction, miRNA-132 was found to be significantly deregulated in glioma tissues. Based on the prediction of the target genes of miR-132, we hypothesized that there is a significant association between miR-132 and matrix metalloproteinase (MMP) 16 (MT3-MMP), a protein of the MMP family. We showed that the up-expression of miR-132 inhibited cell migration and invasion in the human glioma cell lines A172, SHG44, and U87. Furthermore, the overexpression of miR-132 reduced the expression of MMP16 in A172, SHG44, and U87 cells. Taken together, our study suggested that miR-132 affects glioma cell migration and invasion by MMP16 and implicates miR-132 as a metastasis-inhibiting miRNA in gliomas.

MicroRNA-184 inhibits cell proliferation and invasion, and specifically targets TNFAIP2 in Glioma.

BACKGROUND: miRNA-184 is an oncogene in human hepatocellular carcinoma but acts as a tumor suppressor in tongue squamous cell carcinoma. Studies have shown that miR-184 was down-regulated in glioma and TNFα-induced protein 2 (TNFAIP2) was closely related to tumorigenesis. This study aimed to determine the functions of miR-184 in glioma and the mechanisms of miRNA-184-TNFAIP2 mediated glioma progression. METHODS: Real-time reverse-transcription PCR detected expression of miR-184 and TNFAIP2. U87 and U251 cells were transfected with miR-184 mimic, inhibitor, or negative control miRNA, and their invasion abilities were assayed. Cellular proliferation was measured by the cell counting kit-8 assay. miR-184 effects on glioma cell apoptosis and cell cycle were assessed by flow cytometer. Biological information software have predicted that miR-184 could target TNFα-induced protein 2 (TNFAIP2), Which was further validated by Western blot and qRT-PCR in glioma cells. In vivo, U87 cells transduced with either lentiviral over-expressed miR-184 or control lentivirus were injected into nude mice subcutaneously and intracranial respectively. RESULTS: Expression of miR-184 was significantly lower in glioma tissues and cell-lines compared to normal brain tissues. Protein and mRNA expression of TNFAIP2 were inversely correlated with miR-184 in glioma. In vitro, proliferation and invasion abilities were also decreased in U87 and U251 cells after transfection with miR-184 mimic. In vivo, the xenografted tumor size in the miR-184 overexpressing group were smaller than the miR-NC group. Concordantly, U87 and U251 cells transfected with miR-184 mimic had a higher apoptosis rate, triggering an accumulation of cells at the G0/G1 phase and decreased cells in S-phase. CONCLUSIONS: miR-184 could regulate TNFAIP2 expression and affected its translation in glioma. miR-184 could also inhibit glioma progression and might serve as a novel therapeutic target in glioma.

miR-494-3p Regulates Cellular Proliferation, Invasion, Migration, and Apoptosis by PTEN/AKT Signaling in Human Glioblastoma Cells.

Malignant gliomas are the most common primary brain tumors, and the molecular mechanisms involving their progression and recurrence are still largely unclear. Substantial data indicate that the oncogene miR-494-3p is significantly elevated in gliomas, but the molecular functions of miR-494-3p in gliomagenesis are largely unknown. The present study aimed to explore the role of miR-494-3p and its molecular mechanism in human brain gliomas, malignant glioma cell lines, and cancer stem-like cells. The expression level of miR-494-3p in 48 human glioma issues and 8 normal brain tissues was determined using stem-loop real-time polymerase chain reaction (PCR). To study the function of miR-494-3p inhibitor in glioma cells, the miR-494-3p inhibitor lentivirus was used to transfect glioma cells. Transwell invasion system was used to estimate the effects of miR-494-3p inhibitor on the invasiveness of glioma cells. A mouse model was used to test the effect of miR-494-3p inhibitor on glioma proliferation and invasion in vivo. Results showed that the expression of miR-494-3p in human brain glioma tissues was higher than in normal brain tissues. Downregulated expression of miR-494-3p can inhibit the invasion and proliferation and promote apoptosis in glioma cells. Quantitative reverse transcription PCR and Western blotting analysis revealed that the expression of PTEN was increased after downexpression of miR-494-3p in glioma cells (U87 and U251). miR-494-3p inhibitor could prevent migration, invasion, proliferation, and promote apotosis in gliomas through PTEN/AKT pathway. Therefore, the study results have shown that miR-494-3p may act as a therapeutic target in gliomas.