کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
3055354 1186481 2016 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
BAG2 expression dictates a functional intracellular switch between the p38-dependent effects of nicotine on tau phosphorylation levels via the α7 nicotinic receptor
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی عصب شناسی
پیش نمایش صفحه اول مقاله
BAG2 expression dictates a functional intracellular switch between the p38-dependent effects of nicotine on tau phosphorylation levels via the α7 nicotinic receptor
چکیده انگلیسی


• Low BAG2 expression is conducive to nicotine-induced phospho-tau accumulation.
• BAG2 overexpression shifts the effect of nicotine to lowering phospho-tau levels.
• The effects of nicotine on p-tau in the presence or absence of BAG2 is p38-dependent.
• The BAG2-dependent effect of nicotine on p-tau is via the alpha7 nicotinic receptor.

The histopathological hallmarks present in Alzheimer's disease (AD) brain are plaques of Aβ peptide, neurofibrillary tangles of hyperphosphorylated tau protein, and a reduction in nicotinic acetylcholine receptor (nAChR) levels. The role of nAChRs in AD is particularly controversial. Tau protein function is regulated by phosphorylation, and its hyperphosphorylated forms are significantly more abundant in AD brain. Little is known about the relationship between nAChR and phospho-tau degradation machinery. Activation of nAChRs has been reported to increase and decrease tau phosphorylation levels, and the mechanisms responsible for this discrepancy are not presently understood. The co-chaperone BAG2 is capable of regulating phospho-tau levels via protein degradation. In SH-SY5Y cell line and rat primary hippocampal cell culture low endogenous BAG2 levels constitute an intracellular environment conducive to nicotine-induced accumulation of phosphorylated tau protein. Further, nicotine treatment inhibited endogenous expression of BAG2, resulting in increased levels of phosphorylated tau indistinguishable from those induced by BAG2 knockdown. Conversely, overexpression of BAG2 is conducive to a nicotine-induced reduction in cellular levels of phosphorylated tau protein. In both cases the effect of nicotine was p38MAPK-dependent, while the α7 antagonist MLA was synthetic to nicotine treatment, either increasing levels of phospho-Tau in the absence of BAG2, or further decreasing the levels of phospho-Tau in the presence of BAG2. Taken together, these findings reconcile the apparently contradictory effects of nicotine on tau phosphorylation by suggesting a role for BAG2 as an important regulator of p38-dependent tau kinase activity and phospho-tau degradation in response to nicotinic receptor stimulation. Thus, we report that BAG2 expression dictates a functional intracellular switch between the p38-dependent functions of nicotine on tau phosphorylation levels via the α7 nicotinic receptor.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Experimental Neurology - Volume 275, Part 1, January 2016, Pages 69–77
نویسندگان
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