Expression of Rab3b in Human Glioma: Influence on Cell Proliferation and Apoptosis.

BACKGROUND: Glioma is the most common human central nervous system tumour with a high degree of malignancy. Some Rab GTPases have significant effects on glioma. OBJECTIVE: This study aimed to investigate the effect of Rab3b (Rab GTPase3b) on human glioma cell proliferation and apoptosis by silencing Rab3b and to initially verify the value of Rab3b expression for the diagnosis and progression in human glioma. METHODS: Rab3b was silenced by siRNA transfection. Human glioma tissues and normal brain tissues adjacent to glioma were obtained by surgery. Rab3b, P53, Caspase 7, Bax, and Bim mRNA and protein expression levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Cell proliferation was detected by the cell counting kit-8 assay, and the cell cycle and apoptosis were analysed using flow cytometry. RESULTS: Rab3b mRNA and protein expression in human glioma U251 and U87 cells were significantly downregulated after Rab3b silencing. Rab3b silencing inhibited glioma cell proliferation by promoting cell cycle arrest and induced apoptosis by upregulating the expression of apoptosis-related proteins. Rab3b expression in human glioma (n = 33) was significantly higher than that in normal brain tissues adjacent to glioma (n = 15). In addition, Rab3b expression levels in high-grade gliomas (WHO III-IV, n = 19) were also significantly higher than those in low-grade gliomas (WHO I-II, n = 14). CONCLUSION: Rab3b expression levels are significantly related to the progression of gliomas. Moreover, Rab3b silencing not only significantly inhibits cell proliferation in gliomas via cell cycle arrest but also promotes cell apoptosis by upregulating the expression levels of apoptosis-related proteins; however these preliminary in vitro results warrant validation on in vivo studies.

miR-199a-5p targeted regulation of MAGT1 expression in the functional depletion of CD8+T cells in HBV infection.

Magnesium transporter 1 (MAGT1) is a key protein that regulates the level of free Mg2+ in cells. Previous studies found that the downregulation of MAGT1 expression in CD8+T cells of HBV patients was correlated with the decrease of intracellular magnesium. However, the expression of MAGT1 mRNA in the CD8+T cells from HBV patients was not significantly altered, indicating that the change in MAGT1 expression was accomplished through posttranscriptional regulation. Through bioinformatics and qRT-PCR detection, miR-199a-5p was found to have a target gene relationship with MAGT1. The expression levels of miR-199a-5p and MAGT1 in HBV infection were evaluated. Lentivirus assays were used to analyze the effects of miR-199a-5p upregulation and downregulation on the MAGT1 expression level and the immune system. Results showed no significant change in the expression of MAGT1 mRNA in HBV-infected cell lines, but the expression of MAGT1 was downregulated. Additionally, the expression level of miR-199a-5p was significantly increased. To this end, we predicted a target relationship between miR-199a-5p and MAGT1 by using TargetScan and verified this relationship through a luciferase activity reporter gene assay. As a result, MAGT1 was found to be the direct target of miR-199a-5p. The targeted inhibition of MAGT1 induced by miR-199a-5p overexpression led to the immune function depletion of CD8+T cells in HBV patients. Downregulating the expression level of miR-199a-5p could effectively improve the functional depletion of CD8+T cells. These findings indicate that miR-199a-5p and MAGT1 could potentially be used as biomarkers for the diagnosis and treatment of chronic HBV infection.