Institute for Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany.
Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States; Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY, United States.
Brain Behav Immun. 2018 Oct;73:21-33. doi: 10.1016/j.bbi.2018.07.017. Epub 2018 Jul 21.
The accumulation of neurotoxic amyloid-beta (Aβ) in the brain is a characteristic hallmark of Alzheimer's disease (AD). The blood-brain barrier (BBB) provides a large surface area and has been shown to be an important mediator for removal of brain Aβ. Both, the ABC transporter P-glycoprotein (ABCB1/P-gp) and the receptor low-density lipoprotein receptor-related protein 1 (LRP1) have been implicated to play crucial roles in Aβ efflux from brain. Here, with immunoprecipitation experiments, co-immunostainings and dual inhibition of ABCB1/P-gp and LRP1, we show that both proteins are functionally linked, mediating a concerted transcytosis of Aβ through endothelial cells. Late-onset AD risk factor Phosphatidylinositol binding clathrin assembly protein (PICALM) is associated with both ABCB1/P-gp and LRP1 representing a functional link and guiding both proteins through the brain endothelium. Together, our results give more mechanistic insight on Aβ transport across the BBB and show that the functional interplay of different clearance proteins is needed for the rapid removal of Aβ from the brain.
脑内神经毒性淀粉样蛋白-β(Aβ)的积累是阿尔茨海默病(AD)的一个特征性标志。血脑屏障(BBB)提供了一个大的表面积,并已被证明是清除脑 Aβ 的重要介质。ABC 转运蛋白 P-糖蛋白(ABCB1/P-gp)和受体低密度脂蛋白受体相关蛋白 1(LRP1)都被认为在 Aβ从脑内流出中发挥关键作用。在这里,通过免疫沉淀实验、共免疫染色和 ABCB1/P-gp 和 LRP1 的双重抑制,我们表明这两种蛋白在功能上是相关的,通过内皮细胞共同转导 Aβ。晚发性 AD 风险因子磷脂酰肌醇结合网格蛋白装配蛋白(PICALM)与 ABCB1/P-gp 和 LRP1 相关,代表了一种功能联系,并引导这两种蛋白穿过脑内皮细胞。总之,我们的研究结果提供了对 Aβ 通过 BBB 转运的更多机制见解,并表明不同清除蛋白的功能相互作用对于 Aβ 从脑内快速清除是必需的。