Methoxy-X04 is a fluorescent derivative of Congo Red and Thioflavin T, lacking acidic groups, with a smaller molecular weight and increased lipophilicity. Methoxy-X04 can cross the blood-brain barrier and selectively binds to the beta-sheet structures in dense core amyloid-beta (Aβ) plaques. Methoxy-X04 retains its in vitro binding affinity for amyloid-beta (Aβ) protofibrils, Ki=26.8nM. In vitro, Methoxy-X04 can stain plaques, tangles, and cerebral amyloid angiopathy in post-mortem Alzheimer's disease (AD) brain sections, demonstrating good specificity. In vivo, Methoxy-X04 can be used for imaging Aβ amyloid plaques in the brains of living APP/PS1 mice [1,2].
References:
[1] Bisht K, et al. Correlative Light and Electron Microscopy to Study Microglial Interactions with β-Amyloid Plaques. J Vis Exp. 2016 Jun 1;(112):54060.
[2] Klunk WE, et al. Imaging Abeta plaques in living transgenic mice with multiphoton microscopy and methoxy-X04, a systemically administered Congo red derivative. J Neuropathol Exp Neurol. 2002 Sep;61(9):797-805.
Methoxy-X04是一种具有荧光性的刚果红和柯胺G的衍生物，不含酸性基团，分子量更小且亲脂性更强。Methoxy-X04可以穿过血脑屏障，选择性地结合在致密中心淀粉样蛋白Aβ斑块中的β-折叠层。Methoxy-X04 保留对淀粉样蛋白-β（aβ）原纤维的体外结合亲和力 ，Ki= 26.8 nM。Methoxy-X04在体外可对阿兹海默症 (AD) 大脑死后切片中的斑块、缠结和脑血管淀粉样蛋白进行染色，具有良好的特异性。Methoxy-X04在体内可用于APP/PS1小鼠活体内的大脑Aβ淀粉样斑块成像[1,2]。