抗疟药青蒿琥酯通过在血脑屏障上调 PICALM 来预防小鼠淀粉样β病理的发展。

Anti-malaria drug artesunate prevents development of amyloid-β pathology in mice by upregulating PICALM at the blood-brain barrier.

机构信息

Department of Physiology and Neuroscience and the Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, 1501 San Pablo St, Los Angeles, CA, 90089, USA.

出版信息

Mol Neurodegener. 2023 Jan 27;18(1):7. doi: 10.1186/s13024-023-00597-5.

DOI:10.1186/s13024-023-00597-5

PMID:36707892

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC9883925/

Abstract

BACKGROUND

PICALM is one of the most significant susceptibility factors for Alzheimer's disease (AD). In humans and mice, PICALM is highly expressed in brain endothelium. PICALM endothelial levels are reduced in AD brains. PICALM controls several steps in Aβ transcytosis across the blood-brain barrier (BBB). Its loss from brain endothelium in mice diminishes Aβ clearance at the BBB, which worsens Aβ pathology, but is reversible by endothelial PICALM re-expression. Thus, increasing PICALM at the BBB holds potential to slow down development of Aβ pathology.

METHODS

To identify a drug that could increase PICALM expression, we screened a library of 2007 FDA-approved drugs in HEK293t cells expressing luciferase driven by a human PICALM promoter, followed by a secondary mRNA screen in human Eahy926 endothelial cell line. In vivo studies with the lead hit were carried out in Picalm-deficient (Picalm) mice, Picalm; 5XFAD mice and Picalm; Cdh5-Cre; 5XFAD mice with endothelial-specific Picalm knockout. We studied PICALM expression at the BBB, Aβ pathology and clearance from brain to blood, cerebral blood flow (CBF) responses, BBB integrity and behavior.

RESULTS

Our screen identified anti-malaria drug artesunate as the lead hit. Artesunate elevated PICALM mRNA and protein levels in Eahy926 endothelial cells and in vivo in brain capillaries of Picalm mice by 2-3-fold. Artesunate treatment (32 mg/kg/day for 2 months) of 3-month old Picalm; 5XFAD mice compared to vehicle increased brain capillary PICALM levels by 2-fold, and reduced Aβ42 and Aβ40 levels and Aβ and thioflavin S-load in the cortex and hippocampus, and vascular Aβ load by 34-51%. Artesunate also increased circulating Aβ42 and Aβ40 levels by 2-fold confirming accelerated Aβ clearance from brain to blood. Consistent with reduced Aβ pathology, treatment of Picalm; 5XFAD mice with artesunate improved CBF responses, BBB integrity and behavior on novel object location and recognition, burrowing and nesting. Endothelial-specific knockout of PICALM abolished all beneficial effects of artesunate in 5XFAD mice indicating that endothelial PICALM is required for its therapeutic effects.

CONCLUSIONS

Artesunate increases PICALM levels and Aβ clearance at the BBB which prevents development of Aβ pathology and functional deficits in mice and holds potential for translation to human AD.

摘要

背景

PICALM 是阿尔茨海默病（AD）的最重要的易感性因素之一。在人类和小鼠中，PICALM 在脑内皮细胞中高度表达。AD 大脑中的 PICALM 内皮水平降低。PICALM 控制着 Aβ 通过血脑屏障（BBB）的转胞吞作用的几个步骤。其从小鼠脑内皮细胞中的丢失会降低 BBB 处的 Aβ 清除率，从而使 Aβ 病理学恶化，但内皮细胞 PICALM 的重新表达可使其逆转。因此，增加 BBB 处的 PICALM 有可能减缓 Aβ 病理学的发展。

方法

为了鉴定一种可以增加 PICALM 表达的药物，我们在表达荧光素酶的 HEK293t 细胞中筛选了 2007 种已批准的 FDA 药物文库，然后在人 Eahy926 内皮细胞系中进行了二次 mRNA 筛选。用先导化合物对 Picalm 缺陷型（Picalm）小鼠、Picalm；5XFAD 小鼠和 Picalm；Cdh5-Cre；5XFAD 内皮细胞特异性 Picalm 敲除小鼠进行了体内研究。我们研究了 BBB 处的 PICALM 表达、Aβ 病理学和从脑到血的清除率、脑血流（CBF）反应、BBB 完整性和行为。

结果

我们的筛选发现抗疟疾药物青蒿琥酯是先导化合物。青蒿琥酯使 Eahy926 内皮细胞和体内 Picalm 小鼠的脑毛细血管中的 PICALM mRNA 和蛋白水平分别升高了 2-3 倍。与载体相比，用 32mg/kg/天青蒿琥酯治疗 3 个月大的 Picalm；5XFAD 小鼠增加了脑毛细血管中的 PICALM 水平 2 倍，降低了皮质和海马体中的 Aβ42 和 Aβ40 水平以及 Aβ 和硫代黄素 S 负荷，并减少了 34-51%的血管 Aβ 负荷。青蒿琥酯还使循环中的 Aβ42 和 Aβ40 水平增加了 2 倍，证实了 Aβ 从脑到血的清除速度加快。与 Aβ 病理学减轻一致，用青蒿琥酯治疗 Picalm；5XFAD 小鼠改善了新物体位置和识别、挖掘和筑巢的 CBF 反应、BBB 完整性和行为。内皮细胞特异性 PICALM 敲除消除了青蒿琥酯在 5XFAD 小鼠中的所有治疗作用，表明内皮细胞 PICALM 是其治疗作用所必需的。