多功能蛋白P62在tau转基因小鼠脑中的表达

Expression profile of p62 in brain of tau transgenic mice

目的:探讨含P301L转基因小鼠脑中与自噬相关的多功能蛋白p62(p62/SQSTM1/sequestosome 1,p62)的表达情况。方法:取3月龄和9月龄雄性人tau基因P301L突变转基因小鼠及同窝雄性野生型小鼠脑组织,采用Western blotting方法检测各组小鼠脑匀浆中tau蛋白磷酸化水平和p62表达水平,并通过免疫组化的方法检测小鼠脑片海马区域磷酸化tau蛋白和p62的表达情况。结果:Western blotting结果显示,P301L转基因小鼠和野生型小鼠脑内tau蛋白磷酸化和p62蛋白水平均随着年龄的增长而增加;P301L转基因小鼠脑内tau蛋白磷酸化水平高于同龄野生型小鼠,而p62水平低于野生型小鼠。免疫组化染色结果显示,P301L转基因小鼠海马tau蛋白磷酸化水平增高,且阳性神经元的数量随年龄的增长而增加;P301L转基因小鼠海马p62表达较同龄野生型小鼠显著减少。结论:P301L转基因小鼠脑内p62表达量减少,尤其表现在海马区,提示tau蛋白过度磷酸化导致自噬水平异常增高。

Objective To compare the expression profile of multifunctional protein p62(p62/SQSTM1/sequestosome 1,p62)associated with autophagy in brains of tau transgenic mice.Methods Brain homogenates and sections from male P301l tau transgenic mice and their male wild type(C57BL/6)littermates aged 3 and 9 months old(n=4 for each age)were subjected in this study.Western blotting and Immunohistochemical staining analysis were applied to detect the expression level of hyperphosphorylated tau and p62 in brain homogenates.The former measure is used to detect the whole brain and the latter one is for morphologic observation in the hippocampus especially.Results In brains of all mice,it showed an age-dependent increase of hyperphosphorylated tau and p62 in both western blotting and immunohistochemical staining.Hyperphosphorylated tau was elevated as early as 3 months in tau transgenic mice,however,their the expression of p62 was less than wild type mice remarkably at both 3 and 9 months.Conclusion P62 expression increased with aging was decreased in the hippocampus of tau transgenic mice suggesting that hyperphosphorylated tau could activate autophagy excessively.