No abstract

Angiotensin II (Ang II) is a key contributor to glomerular disease by predominantly resulting in podocyte injury, whereas the underlying molecular mechanisms has not been fully understood. This study aimed to investigate if and how ADP-ribosylation factor 6 (Arf6), a small GTP-binding protein, involves Ang II-induced cellular injury in cultured human podocytes. Cellular injury was evaluated with caspase 3 activity, reactive oxygen species (ROS) level and TUNEL assay. Arf6 activity was measured using an Arf6-GTP Pull-Down Assay. Ang II significantly enhanced Arf6 expressions accompanied by increase of Arf6-GTP. The TUNEL-positive cells as well as activated caspase 3, NADPH oxidase 4 protein (Nox4) and ROS levels were dramatically increased in Ang II-treated podocytes, which was prevented by secinH3, an Arf6 activity inhibitor. Induction of ROS by Ang II was inhibited in podocytes with Nox4 knockdown. Ang II-induced elevation of Nox4 and ROS was prevented by Arf6 knockdown. Phpspho-Erk1/2 Thr202/Tyr204 levels were upregulated remarkably following Ang II treatment, and Erk inhibitor LY3214996 significantly downregulated Nox4 expression. In addition, Ang II decreased CD2AP expression. Overexpression of CD2AP prevented Ang IIinduced upregulation of Arf6-GTP. Our data demonstrated that Ang II promotes ROS production and podocytes injury through activation of Arf6-Erk1/2-Nox4 signaling. We also provided evidence that Ang II activates Arf6 by degradation of CD2AP.

Medulloblastoma (MB) is the most prevalent brain tumor that occurs during childhood and originates from cerebellar granule cell precursors. Based on recent studies, the differential expression of several microRNAs is involved in MB, while the role of microRNA‐494 (miR‐494) in MB remains unclear. Therefore, we conducted this study to investigate the regulative role of miR‐494 in MB cells via the p38 mitogen‐activated protein kinase (MAPK) signaling pathway by mediating c‐myc. In the current study, MB cells were collected and transfected with miR‐494 mimic, miR‐494 inhibitor, siRNA‐ c‐myc, and miR‐494 inhibitor + siRNA‐c‐myc. The expressions of miR‐494, c‐myc, p38 MAPK, B‐cell lymphoma‐2 (Bcl‐2), Bcl‐2‐associated X protein (Bax), interleukin‐6 (IL‐6), metadherin (MTDH), phosphatase and tensin homolog (PTEN) and survivin were determined. Cell proliferation, cell‐cycle distribution, apoptosis, migration, and invasion were evaluated. The results revealed that there was a poor expression of miR‐494 and high expression of c‐myc in MB tissues. C‐myc was determined as the target gene of miR‐494. In response to miR‐494 mimic, MB cells were found to have increased Bax and PTEN expressions, as well as cell number in G1 phase and cell apoptosis and decreased c‐myc, p38 MAPK, Bcl‐2, MTDH, IL‐6, and survivin expression and cell number count in the S phase, cell proliferation, migration, and invasion. In conclusion, the results demonstrated that the upregulation of miR‐494 results in the suppression of cell proliferation, migration, and invasion, while it promotes apoptosis of MB cells through the negative mediation of c‐myc, which in turn inactivates the p38 MAPK pathway.

Wilms’ tumor is the most common pediatric renal malignancy. MiRNAs are important regulators in multiple cancers including Wilms’ tumor. In this study, we examined the role of miR-483-3p on proliferation, chemosensitivity, migration, and invasion of Wilms’ tumor cells. The proliferation of Wilms’ tumor cells was examined using WST-1 assay. The migration and invasion of Wilms’ tumor cells were evaluated by transwell migration assay and matrigel invasion assay. The protein expression levels were detected by Western blot. The effect of miR-483-3p on doxorubicin-induced apoptosis in Wilms’ tumor cells was evaluated by caspase-Glo3/7 assay. Forced expression of miR-483-3p promoted the proliferation, migration, and invasion in Wilms’ tumor cells. Meanwhile, miR-483-3p decreased the sensitivity of Wilms’ tumor cells after doxorubicin treatment. MiR-483-3p inhibited the doxorubicin-induced apoptosis in Wilms’ tumor cells by the regulation of BAX and Bcl-2 expression. Furthermore, miR-483-3p regulated epithelial–mesenchymal transition by affecting the expression of E-cadherin, N-cadherin, snail, and vimentin in Wilms’ tumor cells. Further studies showed that the expression levels of PTEN and p-AKT in Wilms’ tumor cells were changed after aberrant expression of miR-483-3p by binding to 3′-UTR of PTEN. Our study suggests that miR-483-3p played important roles in proliferation and progression in Wilms’ tumor cells and might serve as a potential prognostic biomarker and predict chemotherapy response in Wilms’ tumor.

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease characterized by immune-mediated destruction of pancreatic beta-cells. Multiple microRNAs (miRNAs) have been implicated in T1DM pathogenesis. Although histone deacetylase 3 (HDAC3) has been reported to be involved in T1DM, the underlying mechanisms remain to be further elucidated. This study was designed to investigate the potential regulatory role of Hdac3 on T1DM progression. The expression of miR-296-5p and B-cell leukemia-XL (BCL-XL) was determined using RT-qPCR and Western blot assay in peripheral blood mononuclear cells (PBMCs) of patients with T1DM, tumor necrosis factor-α (TNF-α)-and cycloheximide (CHX)-induced cell model, and streptozotocin (STZ)-induced rat model. The binding affinity between miR-296-5p and Bcl-xl was verified by using dual-luciferase reporter gene assay, and the binding between Hdac3 and the promoter region of miR-296-5p was validated using chromatin immunoprecipitation assay. Western blot analysis and flow cytometry were conducted to assess the apoptotic events of lymphocytes. miR-296-5p expression was downregulated while BCL-XL expression was upregulated in PBMCs of patients with T1DM. An adverse correlation was identified between miR-296-5p and Bcl-xl in mouse TE15 B lymphocytes. Bcl-xl was further validated to be targeted and negatively regulated by miR-296-5p in 293 T cells. Hdac3 inhibited miR-296-5p expression by binding to its promoter region. The effects of overexpressed Hdac3 on lymphocyte apoptosis was counterweighed via downregulation of Bcl-xl or upregulation of miR-296-5p, the mechanism of which was further validated in a rat model of DM. Taken together, the Hdac3-mediated upregulation of Bcl-xl via inhibiting miR-296-5p promoter activity enhanced the antiapoptotic capacity of lymphocytes to accelerate the occurrence of T1DM.