Hyperphosphorylation of tau is one of the main hallmarks for Alzheimer's disease (AD) and many other tauopathies. Norepinephrine (NE), a stress-related hormone and 17-β-estradiol (E2) thought to influence tau phosphorylation (p-tau) and AD pathology. The controversy around the impact of NE and E2 requires further clarification. Moreover, the combination effect of physiological and psychological stress and estrogen alteration during menopause, which affect p-tau, has not been addressed. Exposure to E2 is believed to reduce NE release, however, the link between these two hormones and AD at cellular level was also remained unknown. Here, we examined whether NE and E2 treatment of differentiated SH-SY5Y cells affected tau phosphorylation. The involvement of adenosine monophosphate kinase protein kinase (AMPK) and target of Rapamycin (mTOR) as the possible mechanisms, underlying this effect was also investigated. Subsequent to SH-SY5Y differentiation to mature neurons, we treated the cells with NE, E2 and NE plus E2 in presence and absence of Compound C and Rapamycin. Cell viability was not affected by our treatment while our Western blot and immunofluorescent findings showed that exposure to NE and E2 separately, and in combination enhanced p-tau (Ser³⁹⁶) and (Ser²⁶²)/tau but not (Ser²⁰²/Thr²⁰⁵)/tau. Blocking AMPK by Compound C reduced p-tau (Ser³⁹⁶) and (Ser²⁶²), while GSK-3β and PP2A activities were remained unchanged. We also found that blocking mTOR by Rapamycin did not change increased p-tau (Ser³⁹⁶) and (Ser²⁶²) due to NE + E2 treatment. Collectively, our results suggested that tau hyperphosphorylation due to exposure to NE/E2 was mediated by AMPK, the main energy regulator of cells during stress with no significant involvement of mTOR, GSK-3β and PP2A.

τ的过度磷酸化是阿尔茨海默氏病（AD）和许多其他tauopathies的主要标志之一。去甲肾上腺素（NE），一种与压力有关的激素和17-β-雌二醇（E2），被认为会影响tau磷酸化（p-tau）和AD病理。关于NE和E2的影响的争论需要进一步澄清。此外，还没有解决影响绝经期的生理和心理压力以及雌激素改变对p-tau的综合影响。据信暴露于E2可以减少NE的释放，但是，这两种激素与AD在细胞水平之间的联系仍然未知。在这里，我们检查了NE和E2处理分化的SH-SY5Y细胞是否影响tau磷酸化。还研究了腺苷单磷酸激酶蛋白激酶（AMPK）和雷帕霉素靶标（mTOR）参与的可能机制，并探讨了这种作用的潜在原因。SH-SY5Y分化为成熟神经元后，我们在存在和不存在化合物C和雷帕霉素的情况下，用NE，E2和NE加E2处理细胞。细胞存活率不受我们治疗的影响，而我们的蛋白质印迹和免疫荧光结果表明，分别暴露于NE和E2并联合使用可增强p-tau（Ser³⁹⁶）和（Ser ²⁶²）/ tau，但不是（Ser ²⁰² / Thr ²⁰⁵）/ tau。用化合物C阻断AMPK可降低p-tau（Ser ³⁹⁶）和（Ser ²⁶²），而GSK-3β和PP2A活性保持不变。我们还发现，雷帕霉素阻断mTOR并不会改变由于NE + E2处理而增加的p-tau（Ser ³⁹⁶）和（Ser ²⁶²）。总的来说，我们的结果表明，由于暴露于NE / E2而引起的tau过度磷酸化是由AMPK介导的，AMPK是应激期间细胞的主要能量调节剂，而没有mTOR，GSK-3β和PP2A的显着参与。