Name: use of two dimensional semi-denaturing detergent agarose gel electrophoresis to confirm size heterogeneity of amyloid or amyloid-like fibers
Uploaded: 2018-04-26T14:30:00.000+00:00
Duration: 10 min 10 s
Description: Watch this Scientific Journal Video about Use of Two Dimensional Semi-denaturing Detergent Agarose Gel Electrophoresis to Confirm Size Heterogeneity of Amyloid or Amyloid-like Fibers at JoVE.com

这项工作得到了何善衡奖学金的支持。从 NIH/NCATS (TL1TR001104), 韦尔奇基金会赠款 (I-1827) 和研究院 (RGM120502A) R01 赠款 z.w.z. W. 是弗吉尼亚默奇森克姆学者在医学研究和癌症预防和研究所得克萨斯学者 (R1222)。

1. 准备样品
<ol><li>培养 2 x 106淀粉样蛋白, 在10厘米组织培养皿中产生 HT-29 结肠癌细胞, 10 毫升的 Dulbecco 修饰鹰培养基 (DMEM) 含有10% 胎牛血清和青霉素-链霉素。培养细胞过夜在37°c 孵化器与 5% CO2。<ol>
<li>细胞生长到80% 融合后, 用10毫升磷酸盐缓冲的生理盐水 (PBS) 冲洗细胞。加入3毫升胰蛋白酶溶液, 在37摄氏度孵育3分钟。</li>
		<li>细胞完全脱离皿后, 加入10毫升培养基, 将10毫升吸管的细胞转移到15毫升圆锥管。在室温下将细胞以 1000 x g 为3分钟离心。吸入培养基, 并用重悬5毫升培养基中的细胞, 并用细胞计数器计数细胞。板 2 x 106单元格中每两个10厘米的菜肴。</li>
		<li>允许细胞在一夜之间坚持和恢复在37°c 孵化器与 5% CO2。对一道菜进行治疗, 以诱导 20 amyloids 肿瘤坏死因子α (TNF α), 100 nM Smac 模拟, 20 µM 泛 caspase 抑制剂 Z-(芬兰马克11 的形成。组合缩写为慈。把另一盘车当作控制品对待。</li>
	</ol>
</li>
	<li>在适当的时间长度以后, 通常 6 h, 收获细胞裂解。<ol>
<li>用塑料刮刀刮掉盘子上的细胞, 然后用10毫升的吸管将其转移到15毫升圆锥管中。离心细胞在 1000 x g 3 分钟在4摄氏度。</li>
		<li>2次通过 resuspending 在10毫升的冰冷 PBS 和离心在 1000 x g 3 分钟, 在4摄氏度清洗细胞。吸入 PBS 溶液。 注: 这个过程可以在这里暂停冻结细胞颗粒在液氮和储存 at#˗80°c 长达1月。</li>
		<li>将细胞颗粒转移到1.5 毫升的离心管上, 在0.3 毫升的裂解缓冲液中孵育30分钟冰。离心机在 2万 x g 15 分钟在4摄氏度。上清是整个细胞裂解。 注意: 这个过程可以在这里暂停, 将样品储存在-20 摄氏度, 长达几个月。</li>
		<li>根据制造商的协议测量蛋白质浓度的布拉德福德化验。添加 4x SDD 龄加载缓冲器, 准备20µL 的3µg/µL 样品, 室温孵育10分钟。</li>
	</ol>
</li>
</ol>2. 准备和运行凝胶
<ol><li>在玻璃烧杯中添加2克琼脂糖到200毫升的1x 三醋酸盐缓冲液中, 在微波炉中加热以融化琼脂糖。添加1毫升 20% sds, 最终浓度为 0.1% sds。仔细地旋转混合。注意不要在 SDS 添加后产生气泡。</li>
	<li>将琼脂糖溶液倒入15厘米 x 14 厘米的凝胶板中。使用1毫升吸管消除任何气泡。在顶部放一把20好梳子。</li>
	<li>第一维: 吸管60µg 全细胞裂解在极右车道。在 60 V 左右运行凝胶约 4 h (直到染料前面是关于¾通过凝胶) 使用泰含 0.1% SDS 作为运行缓冲。</li>
	<li>第二维: 小心旋转凝胶90°逆时针方向 (图 2A)。用60伏的凝胶大约4小时。 注: 一般运行条件为4伏/厘米凝胶长度。重要的是, 在第一和第二维度上, 运行条件是完全相同的。</li>
</ol>3. 转让
<ol><li>使用毛细管转移方法将蛋白质转移到聚偏聚氟 (PVDF) 膜 (图 2B)。<ol>
<li>将500毫升的传输缓冲器添加到大约20厘米 x 20 厘米的容器中。在容器旁边制作一叠5厘米高的纸巾。堆栈顶部的表面积必须大于凝胶尺寸。</li>
		<li>将14厘米 x 15 厘米的滤纸浸泡在传送缓冲器中, 放在纸巾栈的顶部。注意不要在纸上放皱纹或气泡。用另一张滤纸重复。</li>
		<li>激活 14 cm x 15 cm PVDF 膜在甲醇三十年代然后在过滤器纸上把它层起来小心使用滚筒去除所有气泡。用转移缓冲器冲洗凝胶并将其层在膜上, 再滚出任何气泡。</li>
		<li>覆盖最靠近容器的纸巾的边缘与塑料包装。在下一步施工的纸桥不与纸巾栈直接接触是很重要的。</li>
		<li>在传输缓冲器中浸泡一块15厘米 x 35 厘米的滤纸, 然后将其放在一个端盖上, 另一端位于传输缓冲器的容器中。与另一座桥重复。</li>
		<li>用塑料包装把容器盖住, 在室温下过夜。</li>
	</ol>
</li>
</ol>4. 西方印迹检测
<ol><li>用50毫升的 PBS 冲洗膜, 其中 0.05% Tween-20 (PBST) 在20厘米 x 20 厘米的容器中。在 PBST 中加入20毫升5% 牛奶。在室温下晃动30分钟以阻挡。</li>
	<li>吸管10µL 兔抗 MLKL 抗体成20毫升5% 牛奶在 PBST 和添加到容器。在摇杆上孵化过夜在4摄氏度。</li>
	<li>用20毫升的 PBST 冲洗膜5分钟, 重复5次。</li>
	<li>吸管4µL 的抗兔 HRP 到20毫升5% 牛奶在 PBST 和添加到容器。在2小时的室温下在摇杆上孵化。</li>
	<li>用20毫升的 PBST 冲洗膜5分钟, 重复5次。</li>
	<li>添加增强化学发光基底 (ECL), 并根据制造商的协议暴露在 X 射线胶片。</li>
</ol>

<ol>
	<li>Ross, C. A., Poirier, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protein+aggregation+and+neurodegenerative+disease.">Protein aggregation and neurodegenerative disease.</a> Nature medicine. 10, 10-17 (2004).</li><li>Hou, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MAVS+forms+functional+prion-like+aggregates+to+activate+and+propagate+antiviral+innate+immune+response.">MAVS forms functional prion-like aggregates to activate and propagate antiviral innate immune response.</a> Cell. 146, 448-461 (2011).</li><li>Li, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+RIP1/RIP3+necrosome+forms+a+functional+amyloid+signaling+complex+required+for+programmed+necrosis.">The RIP1/RIP3 necrosome forms a functional amyloid signaling complex required for programmed necrosis.</a> Cell. 150, 339-350 (2012).</li><li>Liu, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MLKL+forms+disulfide+bond-dependent+amyloid-like+polymers+to+induce+necroptosis.">MLKL forms disulfide bond-dependent amyloid-like polymers to induce necroptosis.</a> Proceedings of the National Academy of Sciences of the United States of America. 114, 7450-7459 (2017).</li><li>Uptain, S. M., Lindquist, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prions+as+protein-based+genetic+elements.">Prions as protein-based genetic elements.</a> Annual review of microbiology. 56, 703-741 (2002).</li><li>Halfmann, R., Lindquist, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Screening+for+amyloid+aggregation+by+Semi-Denaturing+Detergent-Agarose+Gel+Electrophoresis.">Screening for amyloid aggregation by Semi-Denaturing Detergent-Agarose Gel Electrophoresis.</a> J Vis Exp. , (2008).</li><li>Sipe, J. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nomenclature+2014:+Amyloid+fibril+proteins+and+clinical+classification+of+the+amyloidosis.">Nomenclature 2014: Amyloid fibril proteins and clinical classification of the amyloidosis.</a> Amyloid : the international journal of experimental and clinical investigation : the official journal of the International Society of Amyloidosis. 21, 221-224 (2014).</li><li>Eisenberg, D. S., Sawaya, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+Studies+of+Amyloid+Proteins+at+the+Molecular+Level.">Structural Studies of Amyloid Proteins at the Molecular Level.</a> Annual review of biochemistry. 86, 69-95 (2017).</li><li>Bagriantsev, S. N., Kushnirov, V. V., Liebman, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Methods in Enzymology. 412, 33-48 (2006).</li><li>Sun, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mixed+lineage+kinase+domain-like+protein+mediates+necrosis+signaling+downstream+of+RIP3+kinase.">Mixed lineage kinase domain-like protein mediates necrosis signaling downstream of RIP3 kinase.</a> Cell. 148, 213-227 (2012).</li><li>He, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Receptor+interacting+protein+kinase-3+determines+cellular+necrotic+response+to+TNF-alpha.">Receptor interacting protein kinase-3 determines cellular necrotic response to TNF-alpha.</a> Cell. 137, 1100-1111 (2009).</li></ol>

作者声明没有利益冲突。

2D SDD 年龄的最关键的方面是电泳条件是相同的第一和第二个维度。在 45° (表明没有离解或退化发生) 的情况下, 检测到一条锋利的对角线的能力取决于在两个电泳中以相同方式迁移的纤维。使用不同的条件, 例如改变电压或运行时间的长短, 将会掩盖这些结果。同样, 与传统的 1D SDD 年龄的情况一样, 煮沸的样品应该避免, 因为这将扰乱淀粉样蛋白和淀粉样的纤维。与所有转移的情况一样, 应注意避?...

由于蛋白质错误折叠, 淀粉样纤维的形成早已被人们所熟知, 它在阿尔茨海默病、帕金森病、亨廷顿病等病理状况中起到了1的作用.最近, 淀粉样蛋白或淀粉样纤维的形成已被证明是人类信号通路的一部分, 包括在抗病毒先天免疫应答中2和 necroptosis3,4, 和在较低的有机体如酵母5,6。因此, 在实验室中检测这些纤维的能力是很重要的。目前, 有三种主要的方法来检测淀粉样蛋白和淀粉样的纤维: 使用染料, EM 和 SDD 年龄。
使用染料, 如刚果红或 Thioflavin T, 提供了快速和容易检测使用显微镜或光谱学7的优势。然而, 在刚果红的情况下, 显微镜下的检测不提供任何蛋白质组成纤维或纤维大小的特异性。同样, 使用光谱学检测刚果红或 Thioflavin T 结合蛋白复合物只提供了积极或消极的结果。
EM 提供了有关纤维的存在的确凿证据, 以及关于光纤长度和直径8的定量信息。然而, 这种方法需要非常严格的净化。此外, EM 是一种专门的技术, 使用昂贵的设备。
SDD 年龄已被用来检测抗 SDS 的巨型道尔顿蛋白复合物, 包括淀粉样蛋白或淀粉样的纤维。它提供了许多优点。首先, 它不需要对纤维进行纯化, 并且很容易请执行 9.其次, 它提供了有关纤维大小的定性信息, 包括纤维 heterogenicity 的相对大小和数量。最后, 由于西方印迹可以在电泳后进行, 所以很容易检测出有抗体的任何蛋白质的存在, 虽然应该指出, 由于 SDD 年龄是半变性, 一些表位可能仍然隐蔽通过抗体使得检测复杂化。
最近, 据报道, 受体相互作用蛋白激酶 1 (RIPK1) 和 3 (RIPK3) 形成淀粉样纤维作为信号平台在 necroptosis 期间, 一个程序性的形式坏死3。在研究这些纤维时, 我们的实验室发现另一种 necroptosis 相关的蛋白质, 混合谱系激酶域样 (MLKL), 也形成淀粉样的纤维4。然而, 在 SDD 年龄的检查, MLKL 纤维的大小似乎有别于 RIPK1 和 RIPK3 纤维, 这似乎彼此相同 (图 1)。这是意外的, 因为众所周知, MLKL 绑定到 RIPK1/RIPK3, 形成称为 necrosome10的 necroptosis 信号复合体。
至少有两种解释。首先, 两个完全不同的淀粉样的纤维可能形成在 necroptosis, 一个含有 RIPK1/RIPK3 和其他含有 MLKL。其次, 在 necroptosis 期间, 只有一种含有 RIPK1/RIPK3/MLKL 的淀粉样纤维可以形成, 但 MLKL 与其他蛋白质的关联性较弱, 在 SDD 时代离解。
为了解决这个问题, 我们建议执行一个二维 (2D) SDD 年龄。在第一和第二维电泳中, SDD 稳定的淀粉样蛋白或淀粉样蛋白纤维将具有相同的迁移模式。这将是可检测的, 将蛋白质转移到膜, 并进行了一个西方的印迹。稳定的纤维会呈现尖锐的对角线图案。任何偏离这一点将表明, 纤维发生变化, 由于 SDS 电泳。

<table><tbody><tr><td>gel electrophoresis unit</td><td>Fisher</td><td>HE99XPRO</td><td>appratus for gel running.</td></tr><tr><td>agrose</td><td>VWR</td><td>97062-250</td><td>For agarose gel.</td></tr><tr><td>paper tower</td><td>Fisher</td><td>19-120-2484</td><td>for transfering</td></tr><tr><td>filter paper</td><td>VWR</td><td>21427-386</td><td>for transfering</td></tr><tr><td>PVDF membrane</td><td>Bio-Rad</td><td>162-0177</td><td>for transfering</td></tr><tr><td>blocking milk powder</td><td>Bio-Rad</td><td>1706404XTU</td><td>for blocking in Western blot</td></tr><tr><td>MLKL antibody</td><td>Genetex</td><td>GTX107538</td><td>rabbit anti-MLKL antibody</td></tr><tr><td>RIPK1 antibody</td><td>BD Biosciences</td><td>610459</td><td>mouse anti-RIPK1 antibody</td></tr><tr><td>RIPK3 antibody</td><td>gift from Dr. Xiaodong Wang</td><td></td><td>rabbit anti-RIPK3. See refenence 11.</td></tr><tr><td>anti-Rabbit-HRP</td><td>Sigma</td><td>A6154</td><td>secondary antibody</td></tr><tr><td>ECL</td><td>Fisher</td><td>WBKLS0500</td><td>Western chemiluminescent HRP substrate</td></tr><tr><td>X-ray film</td><td>Fisher</td><td>F-BX810</td><td>for Western blot result</td></tr><tr><td>DMEM</td><td>Sigma</td><td>D6429</td><td>for cell culture</td></tr><tr><td>fetal bovine serum</td><td>Sigma</td><td>F4135</td><td>for cell culture</td></tr><tr><td>penicilin-streptomycin</td><td>Sigma</td><td>P4333</td><td>for cell culture</td></tr><tr><td>Trypsin solution</td><td>Sigma</td><td>T4049</td><td>for cell culture</td></tr><tr><td>PBS for tissue culture</td><td>Sigma</td><td>D8662</td><td>for cell culture</td></tr><tr><td>recombinant TNF</td><td>made in our lab</td><td></td><td>for inducing necroptosis. See reference 11.</td></tr><tr><td>smac-mimetic</td><td>gift from Dr. Xiaodong Wang</td><td></td><td>for inducing necroptosis. See reference 11.</td></tr><tr><td>ZVAD-FMK</td><td>ApexBio</td><td>A1902</td><td>for inducing necroptosis. See reference 11.</td></tr><tr><td>Cell Counter</td><td>Bio-Rad</td><td>1450102</td><td>Model TC20; for counting cells</td></tr><tr><td>Pierce&amp;trade; BCA Protein Assay Kit</td><td>Thermo Scientific</td><td>23225</td><td>for measuring protein concentration in cell lysates</td></tr><tr><td>Cell lifter</td><td>Fisher</td><td>07-200-364</td><td>to remove cells from dish</td></tr><tr><td>Lysis Buffer (1 L)</td><td></td><td></td><td>20 mL 1 M Tris pH 7.4&lt;br/&gt; 10 mL glycerol&lt;br/&gt; 30 mL 5 M NaCl&lt;br/&gt; 840 mL ddH&lt;sub&gt;2&lt;/sub&gt;O&lt;br/&gt; 10 mL Triton-X100&lt;br/&gt; (protease and phosphates inhibitors as desired)</td></tr><tr><td>10X TAE (1 L)</td><td></td><td></td><td>48.4 g Tris base&lt;br/&gt; 11.42 mL glacial acetic acid&lt;br/&gt; 20 mL 0.5M EDTA pH 8&lt;br/&gt; ddH&lt;sub&gt;2&lt;/sub&gt;0 to 1 L</td></tr><tr><td>4X SDD-AGE loading buffer (50 mL)</td><td></td><td></td><td>5 mL 10X TAE&lt;br/&gt; 10 mL glycerol&lt;br/&gt; 4 mL 20% SDS&lt;br/&gt; 0.5 mL 10% bromophenol blue&lt;br/&gt; 31 mL ddH&lt;sub&gt;2&lt;/sub&gt;O</td></tr><tr><td>TBS Transfer Buffer (1 L)</td><td></td><td></td><td>20 mL 1 M Tris pH 7.4&lt;br/&gt; 30 mL 5 M NaCl&lt;br/&gt; 950 mL ddH&lt;sub&gt;2&lt;/sub&gt;O</td></tr><tr><td>PBST Wash Buffer (1 L)</td><td></td><td></td><td>100 mL 10xPBS&lt;br/&gt; 800 mL ddH&lt;sub&gt;2&lt;/sub&gt;O&lt;br/&gt; 1 mL Tween20</td></tr><tr><td>10X PBS (10 L)</td><td></td><td></td><td>800 g NaCl&lt;br/&gt; 20 g KCl&lt;br/&gt; 144 g Na&lt;sub&gt;2&lt;/sub&gt;HPO&lt;sub&gt;4&lt;/sub&gt;&amp;middot;2H&lt;sub&gt;2&lt;/sub&gt;O&lt;br/&gt; 24 g KH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;&lt;br/&gt; add ddH&lt;sub&gt;2&lt;/sub&gt;O to 10 L</td></tr></tbody></table>

use of two dimensional semi-denaturing detergent agarose gel electrophoresis to confirm size heterogeneity of amyloid or amyloid-like fibers

淀粉样蛋白或像淀粉样的纤维已经与许多人类疾病相关, 现在被发现对许多信号通路是重要的。在不同的实验条件下, 能够很容易地检测出这些纤维的形成, 对于了解它们的潜在功能是至关重要的。许多方法已被用来检测纤维, 但没有一些缺点。例如, 电子显微镜 (EM), 或染色与刚果红或 Thioflavin T 往往需要纯化的纤维。另一方面, 半变性洗涤剂琼脂糖凝胶电泳 (SDD 年龄) 允许检测的 SDS 耐药淀粉样纤维在细胞提取物没有纯化。另外, 它允许比较纤维的大小区别。更重要的是, 它可以用来识别纤维内的特定蛋白质由西方印迹。它的耗时更少, 更容易被更多的实验室所访问。SDD 年龄的结果往往表现出不同程度的异质性。它提出了一个问题, 即非异质性的一部分是由蛋白质复合体在电泳过程中的分离而产生的。由于这个原因, 我们使用了 SDD 年龄的第二个维度来确定 SDD 年龄所看到的大小异质性是否真的是纤维异质性在体内的结果, 而不是由于某些蛋白质的降解或离解而导致电泳。这种方法可以快速、定性地确认淀粉样蛋白或淀粉样蛋白纤维在 SDD 年龄过程中没有部分游离。

在 necroptosis 诱导, RIPK1 和 RIPK3 显示几乎相同的淀粉样蛋白样的模式 (车道2和 4,图 1)。然而, MLKL 纤维更异质, 似乎小于 RIPK1/RIPK3 纤维 (6 车道,图 1)。这促使我们开发了 2D SDD 的方法, 以解决 MLKL 是否形成 RIPK1/RIPK3-independent 纤维或 MLKL 简单离解在 RIPK1/RIPK3/MLKL 年龄的大 SDD 纤维的可能性。
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Use of Two Dimensional Semi-denaturing Detergent Agarose Gel Electrophoresis to Confirm Size Heterogeneity of Amyloid or Amyloid-like Fibers

二维半变性洗涤剂琼脂糖凝胶电泳法确定淀粉样或淀粉样纤维的粒度异质性

在这里, 我们使用二维半变性琼脂糖凝胶电泳, 以确认存在的异质淀粉样纤维的异构大小, 并排除了大小异质性是由于淀粉样纤维在凝胶中离解的可能性运行过程。

Amyloid or amyloid-like fibers have been associated with many human diseases, and are now being discovered to be important for many signaling pathways. ...

use-two-dimensional-semi-denaturing-detergent-agarose-gel

Universidad San Sebastian

Research

JoVE Journal

Biochemistry

9.7K 次观看.  UT Southwestern Medical Center. 在这里, 我们使用二维半变性琼脂糖凝胶电泳, 以确认存在的异质淀粉样纤维的异构大小, 并排除了大小异质性是由于淀粉样纤维在凝胶中离解的可能性运行过程。

视频: Use of Two Dimensional Semi-denaturing Detergent Agarose Gel Electrophoresis to Confirm Size Heterogeneity of Amyloid or Amyloid-like Fibers

SDS-PAGE/Immunoblot Detection of A&beta; Multimers in Human Cortical Tissue Homogenates using Antigen-Epitope Retrieval

The anomalous folding and polymerization of the &beta;-amyloid (A&beta;) peptide is thought to initiate the neurodegenerative cascade in Alzheimer's disease pathogenesis1. A&beta; is predominantly a 40- or 42-amino acid peptide that is prone to self-aggregation into &beta;-sheet-rich amyloid fibrils that are found in the cores of cerebral senile plaques in Alzheimer's disease. Increasing evidence suggests that low molecular weight, soluble A&beta; multimers are more toxic than fibrillar A&beta; amyloid2. The identification and quantification of low- and high-molecular weight multimeric A&beta; species in brain tissue is an essential objective in Alzheimer's disease research, and the methods employed also can be applied to the identification and characterization of toxic multimers in other proteopathies3. Naturally occurring A&beta; multimers can be detected by SDS-polyacrylamide gel electrophoresis followed by immunoblotting with A&beta;-specific antibodies. However, the separation and detection of multimeric A&beta; requires the use of highly concentrated cortical homogenates and antigen retrieval in small pore-size nitrocellulose membranes. Here we describe a technique for the preparation of clarified human cortical homogenates, separation of proteins by SDS-PAGE, and antigen-epitope retrieval/Western blotting with antibody 6E10 to the N-terminal region of the A&beta; peptide. Using this protocol, we consistently detect A&beta; monomers, dimers, trimers, tetramers, and higher molecular weight multimers in cortical tissue from humans with Alzheimer's pathology.

SDS-PAGE/Immunoblot Detection of A&#946; Multimers in Human Cortical Tissue Homogenates using Antigen-Epitope Retrieval

We describe a technique for the preparation of clarified human cortical homogenates, protein separation by SDS-PAGE, antigen retrieval and immunoblotting with an antibody to the A&beta; peptide. Using this protocol, we consistently detect monomeric and multimeric A&beta; in cortical tissue from humans with Alzheimer's pathology.

SDS-PAGE/Immunoblot检测人脑皮层组织中的Aβ多聚匀浆使用抗原表位检索

The anomalous folding and polymerization of the &beta;-amyloid (A&beta;) peptide is thought to initiate the neurodegenerative cascade in Alzheimer's ...

科研

神经科学

A11-positive &#946;-amyloid Oligomer Preparation and Assessment Using Dot Blotting Analysis

&#946;-amyloid (A&#946;) is a hydrophobic peptide with an intrinsic tendency to self-assemble into aggregates. Among various aggregates, A&#946; oligomer is widely accepted as the leading neurotoxin in the progress of Alzheimer&#39;s disease (AD) and is considered to be the crucial event in the pathogenesis of AD. Therefore, A&#946; oligomer inhibitors might prevent neurodegeneration and have the potential to be developed as disease-modifying treatments of AD. However, different formation protocols of A&#946; oligomer might lead to oligomers with different characteristics. Moreover, there are not many methods to effectively screen A&#946;1-42 oligomer inhibitors. An A11 antibody can react with a subset of toxic A&#946;1-42 oligomer with anti-parallel &#946;-sheet structures. In this protocol, we describe how to prepare an A11-positive A&#946;1-42 oligomer-rich sample from a synthetic A&#946;1-42 peptide in vitro and to evaluate relative amounts of A11-positive A&#946;1-42 oligomer in samples by a dot blotting analysis using A11 and A&#946;1-42-specific 6E10 antibodies. Using this protocol, inhibitors of A11-positive A&#946;1-42 oligomer can also be screened from semi-quantitative experimental results.

This protocol describes how to prepare A&#946; oligomers from a synthetic peptide in vitro and to evaluate relative amounts of A&#946; oligomer by a dot blotting analysis.

用斑点印迹分析 A11-positive β淀粉样寡聚物的制备与评价

&#946;-amyloid (A&#946;) is a hydrophobic peptide with an intrinsic tendency to self-assemble into aggregates. Among various aggregates, A&#946; oligomer ...

生物化学

Screening for Amyloid Aggregation by Semi-Denaturing Detergent-Agarose Gel Electrophoresis

Amyloid aggregation is associated with numerous protein misfolding pathologies and underlies the infectious properties of prions, which are conformationally self-templating proteins that are thought to have beneficial roles in lower organisms.  Amyloids have been notoriously difficult to study due to their insolubility and structural heterogeneity.  However, resolution of amyloid polymers based on size and detergent insolubility has been made possible by Semi-Denaturing Detergent-Agarose Gel Electrophoresis (SDD-AGE).  This technique is finding widespread use for the detection and characterization of amyloid conformational variants.  Here, we demonstrate an adaptation of this technique that facilitates its use in large-scale applications, such as screens for novel prions and other amyloidogenic proteins.  The new SDD-AGE method uses capillary transfer for greater reliability and ease of use, and allows any sized gel to be accomodated.  Thus, a large number of samples, prepared from cells or purified proteins, can be processed simultaneously for the presence of SDS-insoluble conformers of tagged proteins.

SDD-AGE is a useful technique for the detection and characterization of amyloid-like polymers in cells. Here we demonstrate an adaptation that makes this technique amenable to large-scale applications.

半变性洗涤剂琼脂糖凝胶电泳筛选淀粉样蛋白聚合

Amyloid aggregation is associated with numerous protein misfolding pathologies and underlies the infectious properties of prions, which are ...

生物学

Consensus Brain-derived Protein, Extraction Protocol for the Study of Human and Murine Brain Proteome Using Both 2D-DIGE and Mini 2DE Immunoblotting

Two-dimensional gel electrophoresis (2DE) is a powerful tool to uncover proteome modifications potentially related to different physiological or pathological conditions. Basically, this technique is based on the separation of proteins according to their isoelectric point in a first step, and secondly according to their molecular weights by SDS polyacrylamide gel electrophoresis (SDS-PAGE). In this report an optimized sample preparation protocol for little amount of human post-mortem and mouse brain tissue is described. This method enables to perform both two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) and mini 2DE immunoblotting. The combination of these approaches allows one to not only find new proteins and/or protein modifications in their expression thanks to its compatibility with mass spectrometry detection, but also a new insight into markers validation. Thus, mini-2DE coupled to western blotting permits to identify and validate post-translational modifications, proteins catabolism and provides a qualitative comparison among different conditions and/or treatments. Herein, we provide a method to study components of protein aggregates found in AD and Lewy body dementia such as the amyloid-beta peptide and the alpha-synuclein. Our method can thus be adapted for the analysis of the proteome and insoluble proteins extract from human brain tissue and mice models too. In parallel, it may provide useful information for the study of molecular and cellular pathways involved in neurodegenerative diseases as well as potential novel biomarkers and therapeutic targets.

A common protein extraction protocol using urea/thiourea/SDS buffer for human and mice brain tissue allows indentification of proteins by 2D-DIGE and their subsequent characterization by mini 2DE immunoblotting. This method enables one to obtain more reproducible and reliable results from human biopsies and experimental models.

共识脑源性蛋白，人类和小鼠脑蛋白质组使用两个2D-DIGE和Mini双向电泳免疫印迹法研究提取协议

Two-dimensional gel electrophoresis (2DE) is a powerful tool to uncover proteome modifications potentially related to different physiological or ...

使用偏振敏感双光子显微镜表征球晶

Polarization-Sensitive Two-Photon Microscopy for a Label-Free Amyloid Structural Characterization

Compared to its one-photon counterpart, two-photon excitation is beneficial for bioimaging experiments because of its lower phototoxicity, deeper tissue penetration, efficient operation in densely packed systems, and reduced angular photoselection of fluorophores. Thus, the introduction of polarization analysis in two-photon fluorescence microscopy (2PFM) provides a more precise determination of molecular organization in a sample compared to standard imaging methods based on linear optical processes. In this work, we focus on polarization-sensitive 2PFM (ps-2PFM) and its application in the determination of molecular ordering within complex bio-structures-amyloid spherulites. Neurodegenerative diseases such as Alzheimer's or Parkinson's are often diagnosed through the detection of amyloids-protein aggregates formed due to an impaired protein misfolding process. Exploring their structure leads to a better understanding of their creation pathway and consequently, to developing more sensitive diagnostic methods. This paper presents the ps-2PFM adapted for the determination of local fibril ordering inside the bovine insulin spherulites and spherical amyloidogenic protein aggregates. Moreover, we prove that the proposed technique can resolve the three-dimensional organization of fibrils inside the spherulite.

作者聚焦:使用偏振敏感双光子显微镜对复杂生物结构进行无创成像 

This paper describes how polarization-sensitive two-photon microscopy could be applied to characterize the local organization within label-free amyloid superstructures-spherulites. It also describes how to prepare and measure the sample, assemble the required setup, and analyze the data to obtain information about the local organization of amyloid fibrils.

偏振敏感双光子显微镜用于无标记淀粉样蛋白结构表征

Compared to its one-photon counterpart, two-photon excitation is beneficial for bioimaging experiments because of its lower phototoxicity, deeper tissue ...

化学

Biochemical Purification and Proteomic Characterization of Amyloid Fibril Cores from the Brain

Proteinaceous fibrillar inclusions are key pathological hallmarks of multiple neurodegenerative diseases. In the early stages of Alzheimer&#39;s disease (AD), amyloid-beta peptides form protofibrils in the extracellular space, which act as seeds that gradually grow and mature into large amyloid plaques. Despite this basic understanding, current knowledge of the amyloid fibril structure, composition, and deposition patterns in the brain is limited. One major barrier has been the inability to isolate highly purified amyloid fibrils from brain extracts. Affinity purification and laser capture microdissection-based approaches have been previously used to isolate amyloids but are limited by the small quantity of material that can be recovered. This novel, robust protocol describes the biochemical purification of amyloid plaque cores using sodium dodecyl sulfate (SDS) solubilization with sucrose density gradient ultracentrifugation and ultrasonication and yields highly pure fibrils from AD patients and AD model brain tissues. Mass spectrometry (MS)-based bottom-up proteomic analysis of the purified material represents a robust strategy to identify nearly all the primary protein components of amyloid fibrils. Previous proteomic studies of proteins in the amyloid coronae have revealed an unexpectedly large and functionally diverse collection of proteins. Notably, after refining the purification strategy, the number of co-purifying proteins was reduced by more than 10-fold, indicating the high purity of the isolated SDS insoluble material. Negative staining and immuno-gold electron microscopy allowed confirmation of the purity of these preparations. Further studies are required to understand the spatial and biological attributes that contribute to the deposition of these proteins into amyloid inclusions. Taken together, this analytical strategy is well-positioned to increase the understanding of amyloid biology.

This biochemical purification method with mass spectrometry-based proteomic analysis facilitates the robust characterization of amyloid fibril cores, which may accelerate the identification of targets for preventing Alzheimer's disease.

来自大脑的淀粉样原纤维核心的生化纯化和蛋白质组学表征

Proteinaceous fibrillar inclusions are key pathological hallmarks of multiple neurodegenerative diseases. In the early stages of Alzheimer&#39;s disease ...

Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis for Protein Analysis: A Technique to Separate and Visualize Proteins Based on Molecular Weight

Source: Sultana, S. et al. <a href="https://www-jove-com.bdigitaluss.remotexs.co/v/62628">Extraction and Visualization of Protein Aggregates after Treatment of Escherichia coli with a Proteotoxic Stressor</a>. J. Vis. Exp. (2021).
This video demonstrates a denaturing polyacrylamide-based separation technique for proteins. This technique helps in the preliminary identification of proteins based on their molecular weights.

用于蛋白质分析的十二烷基硫酸钠聚丙烯酰胺凝胶电泳:一种基于分子量分离和可视化蛋白质的技术

Source: Sultana, S. et al. Extraction and Visualization of Protein Aggregates after Treatment of Escherichia coli with a Proteotoxic Stressor. J. Vis. ...

JoVE Encyclopedia of Experiments

Biological Techniques

Electrophoresis Techniques

Isolation of Amyloid Fibrils from Brain Tissue Extract

Source: Upadhyay, A. et al., <a href="https://app-jove-com.bdigitaluss.remotexs.co/v/63816">Biochemical Purification and Proteomic Characterization of Amyloid Fibril Cores from the Brain.</a> J. Vis. Exp. (2022)
This video demonstrates the protocol for isolating&#160; amyloid fibrils from mouse brain tissue extract using density gradient centrifugation and digestion of non-amyloid proteins.

从脑组织提取物中分离淀粉样蛋白原纤维

All procedures involving animal samples have been reviewed and approved by the appropriate animal ethical review committee.
1. Tissue harvesting and ...

二维半变性洗涤剂琼脂糖凝胶电泳法确定淀粉样或淀粉样纤维的粒度异质性

摘要

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此视频中的章节

SDS-PAGE/Immunoblot检测人脑皮层组织中的Aβ多聚匀浆使用抗原表位检索

用斑点印迹分析 A11-positive β淀粉样寡聚物的制备与评价

半变性洗涤剂琼脂糖凝胶电泳筛选淀粉样蛋白聚合

共识脑源性蛋白，人类和小鼠脑蛋白质组使用两个2D-DIGE和Mini双向电泳免疫印迹法研究提取协议

偏振敏感双光子显微镜用于无标记淀粉样蛋白结构表征

偏振敏感双光子显微镜用于无标记淀粉样蛋白结构表征

偏振敏感双光子显微镜用于无标记淀粉样蛋白结构表征

来自大脑的淀粉样原纤维核心的生化纯化和蛋白质组学表征

用于蛋白质分析的十二烷基硫酸钠聚丙烯酰胺凝胶电泳:一种基于分子量分离和可视化蛋白质的技术

从脑组织提取物中分离淀粉样蛋白原纤维