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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Animals, Cell Line, Cell Proliferation, Cyclin D1, Cyclin E, Mesangial Cells, Mitogen-Activated Protein Kinase 1, Mitogen-Activated Protein Kinase 3, Phosphorylation, Rats, Signal Transduction, Y-Box-Binding Protein 1.
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Does y-box protein 1 stimulate mesangial cell proliferation via activation of ERK1/2? Context: To investigate the effects of Y-box protein 1 (YB-1) on the mitogen-activated protein kinase pathway to ascertain which signaling pathway is involved in YB-1-induced mesangial cell (MC) proliferation. The rat MC line HBZY-1 was transfected with pcDNA3.1-YB-1. Cell proliferation was determined by [(3)H]thymidine incorporation, cell counting and cell-cycle analysis. The expression of cyclins was examined by real-time RT-PCR and immunoblotting analysis. Phosphorylation of c-Raf, MEK1/2, and ERK1/2 was detected by immunoblotting analysis. MCs transfected with YB-1 showed an increased DNA synthesis and number of cells in the S and G2 phases of the cell cycle. The expression of cyclins (cyclin A2, cyclin D1, cyclin E and p27) was increased, while p21 levels were decreased. The expression levels of phosphorylated c-Raf kinase, MEK1/2 and the ERK1/2 proteins were elevated in MCs transfected with YB-1. YB-1-stimulated cell proliferation was blocked by U0126, a specific inhibitor of ERK1/2. ERK1/2 regulated YB-1 expression in MCs stimulated with TGF-beta, an effect that was inhibited by U0126.
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YB-1 has an apparent stimulatory effect on c-Raf, MEK1/2, ERK1/2 and cell-cycle progression in MCs, after which activated ERK1/2 goes on to upregulate YB-1 expression and augment the proliferative effect of YB-1. Final Decision: yes