Does an activation of RAR improve Alzheimer disease by the expression of transthyretin?

以促衰老(SAMP8)小鼠为模型，探讨维甲酸受体激活对促衰老(SAMP8)小鼠抗阿尔茨海默病的作用机制。结果表明，激活RAR可改善SAMP8的记忆功能。但未见TTR蛋白的表达。另一方面，具有α分泌酶活性的与神经发生相关的ADAM10蛋白被RAR激活后显著恢复。由于SAMP8小鼠在本研究中没有表现出淀粉样β蛋白的沉积，因此ADAM10衍生的α分泌酶活性对淀粉样β蛋白的影响尚不清楚。然而，与神经发生相关的Hes5的表达在RAR激活的SAMP8小鼠中显著增加。此外，ADAM10和Hes5的表达呈显著正相关。本研究结果提示，通过恢复ADAM10的表达，RAR的激活改善了SAMP8的记忆功能。

I investigate the mechanism of anti-Alzheimer effect of retinoic acid receptor activation focused on the transthyretin (TTR), by using senescence accelerated (SAMP8) mice. As the results, the activation of RAR improves the memory function of SAMP8. However, the protein expression of TTR was not shown. On the other hands, Adam10 protein, which has α-secretase activity and correlates with neurogenesis, is significantly recovered by the RAR activation. The effect of Adam10-derivedα-secretase activity for amyloid beta is not clear because SAMP8 mice did not show the deposit of amyloid beta in this study. However, the expression of Hes5, which associates with neurogenesis, showed the significant increase in RAR-activated SAMP8 mice. Besides that, the expression of Adam10 and Hes5 are significantly correlated. The results in this study suggest that the RAR activation is improved memory function of SAMP8 by the recovery of Adam10 expression.