siah介导α-synuclein泛素化在其自噬性降解中作用-role of siah - mediated alpha-synuclein ubiquitination in autophagy degradation.docx

SIAH 介导的α-synuclein 泛素化在其自噬性降解中的作用英文摘要The role of SIAH in the autophagic clearance of monoubiquitinated α-synuclein mediated by SIAH AbstractObjective: (1) To observe the role of exogenous toxins MPP+ in SIAH activity and alpha-synuclein monoubiquitination and its degradation pathway . (2) To interfere with SIAH activity on cell viability and alpha- synuclein ubiquitination and its degradation pathway .Methods: Before and after treated by different leves of MPP+(0.25mM、0.5mM、1.0mM) and SIAH-1 antibody（2ug/ml、4ug/ml、8ug/ml）we measured cell viability through the MTT method, at last we used MPP+(0.5mM)、SIAH-1 antibody（4ug/ml）to investigate cell viability of pheochromocytoma (PC12) cell lines, and we detected theexpression levels of α-synuclein, microtubule-associated protein light chain 3(LC3-II), SIAH and E1 through Western Blot and quantified PCR.Results: (1) After treated with MPP+ for 24 h, 0.25mM concentration of MPP+ did notshown significant effect on cell growth state compare with normal condition, but 0.5mM and1.0mM concentration of MPP+ cells became shrinked and round, many cells divorced from plate wall, some processes shortened and were broken. Cell viability significantly decreased in this two concentration of MPP+-treated groups, especially in 1.0mM MPP+ group. (2) SIAH-1 antibody at a concentration of 2, 4 and 8ug/ml showed significant effect on PC12 cells, The cell viability was significantly increased after 24 h exposure to it,especially in 4ug/ml、8ug/ml SIAH-1 antibody group. (3) The expression of α-synuclein,LC3, E1and SIAH was obviously increased in the level of protein and mRNA after treatment of MPP+, compared with untreated group, After treated with SIAH-1 antibody again, this trend has been reversed and the level of E1was significantly increased.Conclusion: In this study, we demonstrated that MPP+ could impair the clearance ofα-synuclein by increasing the activity of SIAH, inducing the up-regulation/aggregation of α-synuclein, which may be delete