Circ_DLEU2 knockdown represses cell proliferation, migration and invasion, and induces cell apoptosis through the miR-582-5p/COX2 pathway in acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML) is a malignant hematological neoplasm in adults. Researche indicates that circular RNAs (circRNAs) play paramount roles in the pathological process of AML. In this study, the role of circ_DLEU2 (circ_0000488) in AML is revealed. METHODS: The expression of circ_DLEU2, microRNA-582-5p (miR-582-5p) and cyclooxygenase 2 (COX2) was determined by quantitative real-time PCR. Protein expression was detected by western blot. Cell proliferation was investigated by cell cycle, 5-Ethynyl-29-deoxyuridine and 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assays. Cell apoptosis was elucidated by apoptosis analysis assay. The targeting relationship between miR-582-5p and circ_DLEU2 or COX2 was predicted by the starbase online database, and identified by a dual-luciferase reporter assay. RESULTS: Circ_DLEU2 and COX2 expression were substantially up-regulated, while miR-582-5p was down-regulated in AML marrow samples and cells compared with control groups. Circ_DLEU2 knockdown suppressed cell proliferation, whereas it induced cell arrest at G0/G1 phase and cell apoptosis in AML; however, these effects were attenuated by miR-582-5p inhibitor. Additionally, circ_DLEU2 was associated with miR-582-5p, and miR-582-5p bound to COX2 in AML cells. Also, we found that circ_DLEU2 regulated COX2 expression by interacting with miR-582-5p. CONCLUSION: Circ_DLEU2 silencing hindered AML malignant progression via downregulating COX2 through sponging miR-582-5p. Our finding provides a theoretical basis for studying circRNA-directed therapy of AML.

Hypoxia Preconditioning Promotes the Proliferation and Migration of Human Urine-Derived Stem Cells in Chronically Injured Liver of Mice by Upregulating CXCR4.

Our previous studies reported that urine-derived stem cells (USCs) possess a strong self-renewal ability and multidirectional differentiation potential and thus are an ideal candidate cell source for hepatocellular transplantation. USC transplantation may repair the pathological changes of chronic liver injury to a certain extent, and hypoxia pretreatment may improve the recovery efficiency of USCs. Therefore, the present study aimed to investigate the possible mechanism of the improved recovery efficiency of hypoxia-pretreated USCs. A chronic liver injury model was established by intraperitoneal injection of carbon tetrachloride into nude mice. USCs were transplanted via caudal vein injection. Hematoxylin and eosin staining and Masson's staining were performed to determine the pathology of the liver. Immunofluorescence and frozen section biopsy were performed to determine differentiation and cell fusion in vivo. Cell coculture was used to detect cell fusion in vitro. The proliferative ability of USCs was evaluated using cell viability and colony formation assays, and the migratory functions of USCs were evaluated using wound healing and transwell assays. The degeneration of hepatocytes and the level of fibrosis in the hypoxia transplantation group were improved compared with the normoxia transplantation group. It was found that exogenous USCs may be differentiated into functional hepatocytes or fused with hepatocytes in vivo. C-X-C motif chemokine (CXC) ligand 12 (CXCL12) expression levels in liver tissue of the chronic liver injury model were upregulated compared with those in the control group. The expression of CXC receptor 4 (CXCR4) in hypoxia-pretreated USCs was also significantly upregulated. The results suggested that USCs fused with different types of liver cells and that hypoxia treatment promoted the fusion rate in vitro by upregulating CXCR4 signaling. Furthermore, hypoxia pretreatment promoted cell proliferation, migration, and cell fusion by inducing CXCR4 signaling, leading to USC-elicited liver tissue recovery following injury in vivo.

Skewed balance of regulatory T cell and inflammatory T cell in IL-17 defect with human metapneumovirus infection.

Human metapneumovirus (hMPV) is a common cause of respiratory infections in children. However, the precise mechanisms underlying the development of hMPV-induced pulmonary pathology remain unknown. Studies show that IL-17 plays an important role in some inflammatory diseases of the airways, including asthma and chronic obstructive pulmonary disease. Here, we generated an IL-17 KO murine model of hMPV infection and used it to characterize the role of IL-17 hMPV-induced pulmonary inflammation. The results demonstrated that the defect in IL-17 resulted in less neutrophil influx into the lungs, along with reduced ventilatory function. Meanwhile, viral infection in IL-17 KO mice increased regulatory T cells (Tregs) and reduced Th1 and Th2 cells in the lung, suggesting that lack of IL-17 skews the immune response in the lung toward an anti-inflammatory profile, as exhibited by a greater number of Treg cells and fewer Th1 and Th2 cells.

Effect of CD40/CD40L signaling on IL-10-producing regulatory B cells in Chinese children with Henoch-Schönlein purpura nephritis.

The aim of the present study was to examine the role and mechanism of interleukin-10 (IL-10)-producing regulatory B cells (B10 cells) in the pathogenesis of Henoch-Schönlein purpura nephritis (HSPN). We examined the percentage of B10 cells, CD19+CD24hiCD38hi B cells, CD19+CD24hiCD27+ B cells, Th17 cells, and T regulatory (Treg) cells within the peripheral blood mononuclear cell (PBMC) population in healthy subjects and HSP/HSPN patients. The percentage of B10 cells and CD19+CD24hiCD38hi B cells was reduced in HSPN patients and that of CD19+CD24hiCD27+ B cells was decreased only in HSPN patients with hematuria and proteinuria or massive proteinuria. The expression of IL-10 by B10 cells and their subsets was decreased in HSPN patients and returned to normal levels in HSP/HSPN patients in remission. B10 cells and their subsets negatively correlated with the Th17/Treg ratio. There was no difference in B10pro + B10 cells, Th17 cells, Treg cells, and the Th17/Treg ratio between children with HSP/HSPN and healthy controls after CD40L stimulation. On the other hand, the level of IL-10 expressed by CD19+CD40+ B cells was decreased in HSPN, and the percentage of B10pro + B10 cells and Treg cells was reduced and that of Th17 cell was increased in the presence of anti-CD40L monoclonal antibody (mAb). Thus, decreased B10 cells and CD19+CD24hiCD38hi B cells may function as an early marker of renal impairment in HSPN. The dysfunction of B10 cells may play a role in the pathogenesis of HSPN by regulating the Th17/Treg balance. Moreover, the CD40/CD40L signaling pathway may play a role in B10 cell differentiation and functional maturation.

LIGHT/IFN-γ triggers ß cells apoptosis via NF-κB/Bcl2-dependent mitochondrial pathway.

LIGHT recruits and activates naive T cells in the islets at the onset of diabetes. IFN-γ secreted by activated T lymphocytes is involved in beta cell apoptosis. However, whether LIGHT sensitizes IFNγ-induced beta cells destruction remains unclear. In this study, we used the murine beta cell line MIN6 and primary islet cells as models for investigating the underlying cellular mechanisms involved in LIGHT/IFNγ - induced pancreatic beta cell destruction. LIGHT and IFN-γ synergistically reduced MIN6 and primary islet cells viability; decreased cell viability was due to apoptosis, as demonstrated by a significant increase in Annexin V(+) cell percentage, detected by flow cytometry. In addition to marked increases in cytochrome c release and NF-κB activation, the combination of LIGHT and IFN-γ caused an obvious decrease in expression of the anti-apoptotic proteins Bcl-2 and Bcl-xL, but an increase in expression of the pro-apoptotic proteins Bak and Bax in MIN6 cells. Accordingly, LIGHT deficiency led to a decrease in NF-κB activation and Bak expression, and peri-insulitis in non-obese diabetes mice. Inhibition of NF-κB activation with the specific NF-κB inhibitor, PDTC (pyrrolidine dithiocarbamate), reversed Bcl-xL down-regulation and Bax up-regulation, and led to a significant increase in LIGHT- and IFN-γ-treated cell viability. Moreover, cleaved caspase-9, -3, and PARP (poly (ADP-ribose) polymerase) were observed after LIGHT and IFN-γ treatment. Pretreatment with caspase inhibitors remarkably attenuated LIGHT- and IFNγ-induced cell apoptosis. Taken together, our results indicate that LIGHT signalling pathway combined with IFN-γ induces beta cells apoptosis via an NF-κB/Bcl2-dependent mitochondrial pathway.