Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, Sahlgrenska Academy, University of Gothenburg, SE-431 80 Mölndal, Sweden.
Neurodegener Dis. 2009;6(5-6):258-62. doi: 10.1159/000264639. Epub 2009 Dec 3.
Accumulation of amyloid beta (Abeta) in the brain is believed to represent one of the earliest events in the Alzheimer disease process. Abeta is generated from amyloid precursor protein after sequential cleavage by beta- and gamma-secretase. Alternatively, alpha-secretase cleaves within the Abeta sequence, thus, precluding the formation of Abeta. A lot of research has focused on Abeta production, while less is known about the non-amyloidogenic pathway. We have previously shown that Abeta is present in human cerebrospinal fluid (CSF) as several shorter C-terminal truncated isoforms (e.g. Abeta1-15 and Abeta1-16), and that the levels of these shorter isoforms are elevated in media from cells that have been treated with gamma-secretase inhibitors.
To explore the effect of N-[N-(3,5-difluorophenacetyl-L-alanyl)]-S-phenylglycine t-butyl ester (DAPT), a gamma-secretase-inhibitor, treatment on the Abeta isoform pattern in brain tissue and CSF from Tg2576 mice.
Immunoprecipitation using the anti-Abeta antibodies 6E10 and 4G8 was combined with either matrix-assisted laser desorption/ionization time-of-flight mass spectrometry or nanoflow liquid chromatography and tandem mass spectrometry.
All fragments longer than and including Abeta1-17 displayed a tendency towards decreased levels upon gamma-secretase inhibition, whereas Abeta1-15 and Abeta1-16 indicated slightly elevated levels during treatment.
These data suggest that Abeta1-15 and Abeta1-16 may be generated through a third metabolic pathway independent of gamma-secretase, and that these Abeta isoforms may serve as biomarkers for secretase inhibitor treatment.
在阿尔茨海默病的进程中，人们认为淀粉样蛋白β（Abeta）在大脑中的积累是最早的事件之一。Abeta 是在β和γ-分泌酶连续切割淀粉样前体蛋白后产生的。或者，α-分泌酶在 Abeta 序列内切割，从而防止 Abeta 的形成。大量研究集中在 Abeta 的产生上，而对非淀粉样形成途径知之甚少。我们之前已经表明，Abeta 以几种较短的 C 端截断同种型（例如 Abeta1-15 和 Abeta1-16）的形式存在于人类脑脊液（CSF）中，并且这些较短同种型的水平在已经用 γ-分泌酶抑制剂处理的细胞的培养基中升高。
探索 N-[N-（3,5-二氟苯乙酰基-L-丙氨酰]-S-苯甘氨酸叔丁酯（DAPT），一种γ-分泌酶抑制剂，对 Tg2576 小鼠脑组织和 CSF 中 Abeta 同种型模式的影响。
使用抗 Abeta 抗体 6E10 和 4G8 进行免疫沉淀，结合基质辅助激光解吸/电离飞行时间质谱或纳流液相色谱和串联质谱。
所有长度超过 Abeta1-17 的片段在 γ-分泌酶抑制后都显示出降低的趋势，而 Abeta1-15 和 Abeta1-16 在治疗期间显示出略微升高的水平。
这些数据表明 Abeta1-15 和 Abeta1-16 可能通过独立于 γ-分泌酶的第三种代谢途径产生，并且这些 Abeta 同种型可能作为分泌酶抑制剂治疗的生物标志物。
