Gordon Center for Medical Imaging, Massachusetts General Hospital, Boston, MA, USA.
Genetics and Aging Research Unit, McCance Center for Brain Health, Mass General Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA.
J Alzheimers Dis. 2021;80(2):775-786. doi: 10.3233/JAD-201419.
Cromolyn is an anti-neuroinflammatory modulator with a multifactorial mechanism of action that has been shown to inhibit amyloid-β (Aβ) aggregation and enhance microglial uptake and clearance of Aβ.
We report the effects of fluoro-cromolyn derivatives on microglial cell toxicity and microglial clearance of Aβ42.
Microglial cell toxicity for cromolyn derivatives were determined in naive BV2 microglial cells. Microglial clearance assays were performed with Aβ42 in naive BV2 microglial cell line and single cell clone BV2 line expressing CD33WT. PET imaging was performed for three F-18 analogs in a rhesus macaque.
All compounds but derivative 8 exhibited low microglial cell toxicity. Cromolyn 1 and derivatives 2, 4, and 7 displayed an increased uptake on Aβ42 in naïve BV2 microglial cells. Derivative 4 increased Aβ42 uptake in a dose-dependent manner and at 75μM resulted in a one-fold increase in Aβ42 uptake in BV2-CD33WT. PET imaging for three [18F]cromolyn analogs revealed the order of brain tracer penetration to be 4a > 10 > 2a. Tracer 4a exhibited enhanced uptake in areas of high perfusion (putamen, grey matter, and cerebellum) and lower signal in areas of lower perfusion (caudate, thalamus, and white matter).
Substantial uptake of Aβ42 in both naïve BV2 and BV2-CD33WT cells observed with 4 indicate conversion of microglial cells from a pro-inflammatory to an activation state favoring Aβ phagocytosis/clearance. These findings suggest that a fluoro-cromolyn analog could reduce fibril-prone Aβ42in vivo and thereby serve as a therapeutic for the treatment and prevention of AD.
克仑硫脲是一种具有多种作用机制的抗神经炎症调节剂，已被证明可抑制淀粉样蛋白-β（Aβ）聚集，并增强小胶质细胞对 Aβ 的摄取和清除。
我们报告氟代克仑硫脲衍生物对小胶质细胞毒性和小胶质细胞对 Aβ42 清除的影响。
在原代 BV2 小胶质细胞中测定克仑硫脲衍生物对小胶质细胞的毒性。在原代 BV2 小胶质细胞系和表达 CD33WT 的单细胞克隆 BV2 系中进行 Aβ42 的小胶质细胞清除实验。在恒河猴中进行三种 F-18 类似物的 PET 成像。
除衍生物 8 外，所有化合物均表现出较低的小胶质细胞毒性。克仑硫脲 1 及其衍生物 2、4 和 7 在原代 BV2 小胶质细胞中显示出对 Aβ42 的摄取增加。衍生物 4 呈剂量依赖性增加 Aβ42 的摄取，在 75μM 时，BV2-CD33WT 中 Aβ42 的摄取增加了一倍。三种[18F]克仑硫脲类似物的 PET 成像显示，脑示踪剂穿透的顺序为 4a > 10 > 2a。示踪剂 4a 在高灌注区（壳核、灰质和小脑）表现出增强的摄取，而在低灌注区（尾状核、丘脑和白质）表现出较低的信号。
在原代 BV2 和 BV2-CD33WT 细胞中观察到的 4 对 Aβ42 的大量摄取表明，小胶质细胞从促炎状态转变为有利于 Aβ 吞噬/清除的激活状态。这些发现表明，氟代克仑硫脲类似物可减少体内纤维状 Aβ42 的形成，从而可用作 AD 的治疗和预防药物。
