The peptide KLVFF-K(6) promotes beta-amyloid(1-40) protofibril growth by association but does not alter protofibril effects on cellular reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT).
The peptide KLVFF-K(6) promotes beta-amyloid(1-40) protofibril growth by association but does not alter protofibril effects on cellular reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT).
复制标题
肽 KLVFF-K(6) 通过缔合促进 β-淀粉样蛋白 (1-40) 原纤维生长，但不会改变原纤维对 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四唑的细胞还原作用
DOI：
10.1124/mol.64.5.1160
复制
发表时间：
2003
影响因子：
3.6
通讯作者：
T. Rosenberry
中科院分区：
文献类型：
--
作者：
M. Moss;M. Nichols;D. K. Reed;J. Hoh;T. Rosenberry
Lowe等人观察到肽KLVFF-K6同时增强淀粉样β蛋白（Abeta）原纤维形成并降低细胞毒性，如在3-（4，5-二甲基噻唑-2-基）-2，5-二苯基四唑溴化物（MTT）还原测定中所测量的。据推测，由KLVFF-K6诱导的加速的Abeta聚集和沉淀可能导致毒性较低的不溶性原纤维的增加，代价是毒性更高的可溶性原纤维。在以前的研究中，我们区分了两种模式的原纤维生长：单体沉积和直接的原纤维-原纤维协会伸长。这些生长机制可以通过改变Abeta单体和NaCl浓度来解决。使用旨在分离这些不同模式的原纤维生长的测定，我们在这里报告，在KLVFF-K6的存在下形成的较大的Abeta聚集体导致增强的原纤维协会。3 H-辐射甲基化KLVFF-K6与相关的原纤维结合，表观Kd为180 nM，在此范围内的游离[3 H]KLVFF-K6浓度足以将可溶性原纤维转化为可沉积的原纤维。然而，通过KLVFF-K6促进Abeta原纤维缔合对Abeta诱导的细胞MTT减少的降低没有影响。因此，我们的数据不支持用KLVFF-K6形成的不溶性原纤维比可溶性原纤维毒性小的提议。KLVFF-K6不改变单体沉积引起的原纤维伸长速率。相比之下，当加入到使用尺寸排阻色谱分离的Abeta单体中时，KLVFF-K6抑制原纤维形成，如通过硫磺素T荧光测量的，并且这种抑制被未能改变细胞MTT减少所抵消。
The peptide KLVFF-K6 was observed by Lowe et al. to simultaneously enhance amyloid beta-protein (Abeta) fibrillogenesis and decrease cellular toxicity, as measured in a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. It was postulated that accelerated Abeta aggregation and precipitation induced by KLVFF-K6 may lead to an increase in less toxic insoluble fibrils at the expense of more toxic soluble protofibrils. In a previous study, we distinguished between two modes of protofibril growth: elongation by monomer deposition and direct protofibril-protofibril association. These growth mechanisms could be resolved by varying Abeta monomer and NaCl concentrations. Using assays designed to isolate these distinct modes of protofibril growth, we report here that larger Abeta aggregates formed in the presence of KLVFF-K6 resulted from enhanced protofibril association. 3H-Radiomethylated KLVFF-K6 bound to associated protofibrils with an apparent Kd of 180 nM, and concentrations of free [3H]KLVFF-K6 in this range were sufficient to convert soluble protofibrils to sedimentable fibrils. However, promotion of Abeta protofibril association by KLVFF-K6 had no effect on Abeta-induced decreases in cellular MTT reduction. Therefore, our data do not support the proposal that insoluble fibrils formed with KLVFF-K6 are less toxic than soluble protofibrils. KLVFF-K6 did not alter rates of protofibril elongation by monomer deposition. In contrast, when added to Abeta monomers isolated with the use of size-exclusion chromatography, KLVFF-K6 inhibited fibrillogenesis, as measured by thioflavin T fluorescence, and this inhibition was paralleled by a failure to alter cellular MTT reduction.
登录
查看更多内容
影响因子：
2.2
作者：
Nociari, MM;Shalev, A;Russo, C
通讯作者：
Russo, C
影响因子：
3.9
作者：
MILLER, DL;PAPAYANNOPOULOS, IA;IQBAL, K
通讯作者：
IQBAL, K
影响因子：
2.9
作者：
Pallitto, MM;Ghanta, J;Murphy, RM
通讯作者：
Murphy, RM
影响因子：
2.9
作者：
Lowe, TL;Strzelec, A;Murphy, RM
通讯作者：
Murphy, RM