Downregulation of microRNA-149 in retinal ganglion cells suppresses apoptosis through activation of the PI3K/Akt signaling pathway in mice with glaucoma.

Glaucoma represents a major cause of blindness, generally associated with elevated intraocular pressure (EIOP). The aim of the present study was to investigate whether microRNA-149 (miR-149) affects retinal ganglion cells (RGCs) and the underlying mechanism based on a mouse model of chronic glaucoma with EIOP. The successfully modeled mice were administered with mimics or inhibitors of miR-149. Next, the number of RGCs, ultrastructural changes of RGCs, and purity of RGCs in the retinal tissues were detected. Moreover, the RGCs were collected and subsequently treated with 60 mmHg pressure and transfected with a series of plasmids aiding in the regulation of the expression of miR-149 and betacellulin (BTC). The levels of miR-149, BTC, phosphatidylinositol 3-kinase (PI3K), and Akt were subsequently determined. Finally, RGC viability and apoptosis were detected accordingly. Dual luciferase reporter gene assay provided validation, highlighting BTC was indeed a target gene of miR-149. The downregulation of miR-149 is accompanied by an increased number of RGCs and decreased ultrastructural RGC alterations. Additionally, downregulated miR-149 was noted to increase the levels of BTC, PI3K, and Akt in both the retinal tissues and RGCs, whereas the silencing of miR-149 was observed to promote the viability of RGC and inhibit RGC apoptosis. Taken together, the results of the current study provided validation suggesting that the downregulation of miR-149 confers protection to RGCs by means of activating the PI3K/Akt signaling pathway via upregulation of BTC in mice with glaucoma. Evidence presented indicated the promise of miR-149 inhibition as a potential therapeutic strategy for glaucoma treatment.

Relationship Between Plasma Jagged1 Protein Level and Coronary Collateral Circulation in Patients With Coronary Artery Disease / 中国循环杂志

Objective: To explore the relationship between plasma Jagged1 protein level and coronary collateral circulation (CCC) formation in patients with coronary artery disease(CAD). Methods: According to coronary angiography (CAG) examination, our research was categorized in 2 groups: CAD group, n=89 patients with at least one of left anterior descending (LAD), left circumflex(LCX) or right coronary artery(RCA) stenosis ≥ 95％ and Control group, n=30 subjects without abnormal findings by CAG. Based on Rentrop grading system, CAD group was further divided into 2 subgroups: Good CCC subgroup, n=42 patients with Rentrop grade ≥ 2 and Poor CCC subgroup, n=47 patients with Rentrop grade≤1. Plasma levels of Jagged1 protein,vascular endothelial growth factor (VEGF) were measured by ELISA and the relevant correlation study was conducted by multivariate regression analysis. Results: Compared with Control group, CAD group had increased plasma levels of Jagged1 protein (38.74±10.60)ng/L vs (23.04±8.97)ng/L and elevated VEGF (113.98±30.80)pg/L vs (72.73±14.55)pg/L. Compared with Poor CCC subgroup, Good CCC subgroup presented increased Jagged1 protein (46.77±8.49)ng/L vs (31.56±6.26)ng/L and elevated VEGF (128.10±20.24) pg/L vs (92.43±21.09)pg/L. Correlation study showed that Jagged1 protein was positively related to VEGF in CAD patients (r=0.730, P<0.01); multivariate regression analysis indicated that Jagged1 protein (OR=1.318, P=0.000) and VEGF (OR=1.043, P=0.043) were the independent predictors for CCC processing.Conclusion: CAD patients with good CCC had the higher plasma Jagged1 protein level than the patients with poor CCC which implied that Jagged1 protein played important role in CCC processing, such finding may provide a new direction for treating CAD patients in clinical practice.

Protective effect of O6-methylguanine-DNA-methyltransferase on mammalian cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>O(6)-methylguanine-DNA-methyltransferase (MGMT) is a specific DNA revising enzyme transferring alkylated groups from DNA to its cysteine residue to avoid the abnormal twisting of DNA. Therefore, it is one of the drug resistant genes targeted in the treatment of cancer. This study explored the protective effect of MGMT gene transferred into mammalian cells.</p><p><b>METHODS</b>Mammalian expression vector containing the MGMT gene cloned from human hepatocytes by RT-PCR was constructed and transferred into K562 cells and human peripheral blood mononuclear cells (PBMCs) via liposome, then assayed for gene expression at RNA and protein levels. MTT assay was used to check the drug resistance of cells transfected with MGMT gene.</p><p><b>RESULTS</b>MGMT gene was successfully cloned. Real-time PCR showed that the mRNA expression in gene transfected groups in K562 cell line and PBMC were 13.4 and 4.0 times that of the empty vector transfected groups respectively.</p><p><b>RESULTS</b>of Western blotting showed distinct higher expression of MGMT in gene transfected group than in other two groups. The IC(50) values increased to 7 and 2 times that of the original values respectively in stable transfected K562 cells and transient transfected PBMC.</p><p><b>CONCLUSION</b>The alkylating resistance of eukaryotic cells is enhanced after being transfected with MGMT gene which protein product performs the protective function, and may provide the reference for the protective model of peripheral blood cells in cancer chemotherapy.</p>