Name: visualization and quantification of tgf&#946;/bmp/smad signaling under different fluid shear stress conditions using proximity-ligation-assay
Uploaded: 2021-09-14T13:00:00
Description: Watch this Scientific Journal Video about Visualization and Quantification of TGFÃŽÂ²/BMP/SMAD Signaling under Different Fluid Shear Stress Conditions using Proximity-Ligation-Assay at JoVE.com

我们感谢 Maria Reichenbach 博士和 Christian Hiepen 博士对流程设置系统的支持，并感谢 Eleanor Fox 和 Yunyun Xiao 对手稿的批判性阅读。P-L.M.由国际马克斯普朗克研究学院IMPRS-Biology and Computing（IMPRS-BAC）资助。PK获得了DFG-SFB1444的资助。图 1 是使用 BioRender 创建的。

1. 细胞培养和流体剪切应力暴露
注：以人脐静脉EC（HUVECs）为例研究SS诱导的SMAD相互作用。下面描述的方案可以应用于每种SS响应细胞类型。
<ol><li>在37°C下用0.1%猪皮明胶在PBS中涂覆6通道载玻片30分钟。</li>
	<li>在预包被的6通道载玻片中以每mL2.5×10 6 个细胞的密度在30μL M199全培养基中接种HUVECs。 注：有关如何在流动载玻片中播种细胞的更多信息，请参见参考文献<...

<ol>
	<li>Yadin, D., Knaus, P., Mueller, T. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+insights+into+BMP+receptors:+Specificity,+activation+and+inhibition.">Structural insights into BMP receptors: Specificity, activation and inhibition.</a> Cytokine and Growth Factor Reviews. 27, 13-34 (2016).</li><li>Sieber, C., Kopf, J., Hiepen, C., Knaus, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+advances+in+BMP+receptor+signaling.">Recent advances in BMP receptor signaling.</a> Cytokine and Growth Factor Reviews. 20 (5-6), 343-355 (2009).</li><li>Hiepen, C., 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=BMPR2+acts+as+a+gatekeeper+to+protect+endothelial+cells+from+increased+TGF&#946;+responses+and+altered+cell+mechanics.">BMPR2 acts as a gatekeeper to protect endothelial cells from increased TGF&#946; responses and altered cell mechanics.</a> PLoS Biology. 17 (12), 3000557 (2019).</li><li>Hildebrandt, 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=ActivinA+induced+SMAD1/5+Signaling+in+an+iPSC+derived+EC+model+of+Fibrodysplasia+Ossificans+Progressiva+(FOP)+can+be+rescued+by+the+drug+candidate+saracatinib.">ActivinA induced SMAD1/5 Signaling in an iPSC derived EC model of Fibrodysplasia Ossificans Progressiva (FOP) can be rescued by the drug candidate saracatinib.</a> Stem Cell Reviews and Reports. , (2021).</li><li>Goumans, M. 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=Balancing+the+activation+state+of+the+endothelium+via+two+distinct+TGF-beta+type+I+receptors.">Balancing the activation state of the endothelium via two distinct TGF-beta type I receptors.</a> The EMBO Journal. 21 (7), 1743-1753 (2002).</li><li>Goumans, M. 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=Activin+receptor-like+kinase+(ALK)1+is+an+antagonistic+mediator+of+lateral+TGFbeta/ALK5+signaling.">Activin receptor-like kinase (ALK)1 is an antagonistic mediator of lateral TGFbeta/ALK5 signaling.</a> Molecular Cell. 12 (4), 817-828 (2003).</li><li>Daly, A. C., Randall, R. A., Hill, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transforming+growth+factor+beta-induced+Smad1/5+phosphorylation+in+epithelial+cells+is+mediated+by+novel+receptor+complexes+and+is+essential+for+anchorage-independent+growth.">Transforming growth factor beta-induced Smad1/5 phosphorylation in epithelial cells is mediated by novel receptor complexes and is essential for anchorage-independent growth.</a> Molecular and Cellular Biology. 28 (22), 6889-6902 (2008).</li><li>Ramachandran, A., 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=TGF-&#946;+uses+a+novel+mode+of+receptor+activation+to+phosphorylate+SMAD1/5+and+induce+epithelial-to-mesenchymal+transition.">TGF-&#946; uses a novel mode of receptor activation to phosphorylate SMAD1/5 and induce epithelial-to-mesenchymal transition.</a> eLife. 7, 31756 (2018).</li><li>Flanders, K. C., 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=Brightfield+proximity+ligation+assay+reveals+both+canonical+and+mixed+transforming+growth+factor-&#946;/bone+morphogenetic+protein+Smad+signaling+complexes+in+tissue+sections.">Brightfield proximity ligation assay reveals both canonical and mixed transforming growth factor-&#946;/bone morphogenetic protein Smad signaling complexes in tissue sections.</a> The Journal of Histochemistry and Cytochemistry : The Official Journal of The Histochemistry Society. 62 (12), 846-863 (2014).</li><li>Miyazono, K., Maeda, S., Imamura, T., Dijke, P. T., Heldin, C. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Smad Signal Transduction: Smads in Proliferation, Differentiation and Disease. , 277-293 (2006).</li><li>Goumans, M. J., Zwijsen, A., Ten Dijke, P., Bailly, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bone+morphogenetic+proteins+in+vascular+homeostasis+and+disease.">Bone morphogenetic proteins in vascular homeostasis and disease.</a> Cold Spring Harbor Perspectives in Biology. 10 (2), 031989 (2018).</li><li>Cai, J., Pardali, E., S&#225;nchez-Duffhues, G., ten Dijke, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BMP+signaling+in+vascular+diseases.">BMP signaling in vascular diseases.</a> FEBS Letters. 586 (14), 1993-2002 (2012).</li><li>Cunha, S. I., Magnusson, P. U., Dejana, E., Lampugnani, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deregulated+TGF-&#946;/BMP+signaling+in+vascular+malformations.">Deregulated TGF-&#946;/BMP signaling in vascular malformations.</a> Circulation research. 121 (8), 981-999 (2017).</li><li>MacCarrick, G., 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=Loeys-Dietz+syndrome:+a+primer+for+diagnosis+and+management.">Loeys-Dietz syndrome: a primer for diagnosis and management.</a> Genetics in Medicine : An Official Journal of the American College of Medical Genetics. 16 (8), 576-587 (2014).</li><li>Baeyens, N., Bandyopadhyay, C., Coon, B. G., Yun, S., Schwartz, 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=Endothelial+fluid+shear+stress+sensing+in+vascular+health+and+disease.">Endothelial fluid shear stress sensing in vascular health and disease.</a> The Journal of Clinical Investigation. 126 (3), 821-828 (2016).</li><li>Min, E., 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=Activation+of+Smad+2/3+signaling+by+low+shear+stress+mediates+artery+inward+remodeling.">Activation of Smad 2/3 signaling by low shear stress mediates artery inward remodeling.</a> bioRxiv. , 691980 (2019).</li><li>Zhou, 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=BMP+receptor-integrin+interaction+mediates+responses+of+vascular+endothelial+Smad1/5+and+proliferation+to+disturbed+flow.">BMP receptor-integrin interaction mediates responses of vascular endothelial Smad1/5 and proliferation to disturbed flow.</a> Journal of Thrombosis and Haemostasis. 11 (4), 741-755 (2013).</li><li>Zhou, 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=Force-specific+activation+of+Smad1/5+regulates+vascular+endothelial+cell+cycle+progression+in+response+to+disturbed+flow.">Force-specific activation of Smad1/5 regulates vascular endothelial cell cycle progression in response to disturbed flow.</a> Proceedings of the National Academy of Sciences of the United States of America. 109 (20), 7770-7775 (2012).</li><li>van Dijk, R. A., 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=Visualizing+TGF-&#946;+and+BMP+signaling+in+human+atherosclerosis:+A+histological+evaluation+based+on+Smad+activation.">Visualizing TGF-&#946; and BMP signaling in human atherosclerosis: A histological evaluation based on Smad activation.</a> Histology and Histopathology. 27 (3), 387-396 (2012).</li><li>Derwall, M., 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=Inhibition+of+bone+morphogenetic+protein+signaling+reduces+vascular+calcification+and+atherosclerosis.">Inhibition of bone morphogenetic protein signaling reduces vascular calcification and atherosclerosis.</a> Arteriosclerosis, Thrombosis, and Vascular Biology. 32 (3), 613-622 (2012).</li><li>Fredriksson, 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=Protein+detection+using+proximity-dependent+DNA+ligation+assays.">Protein detection using proximity-dependent DNA ligation assays.</a> Nature Biotechnology. 20 (5), 473-477 (2002).</li><li>S&#246;derberg, O., 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=Direct+observation+of+individual+endogenous+protein+complexes+in+situ+by+proximity+ligation.">Direct observation of individual endogenous protein complexes in situ by proximity ligation.</a> Nature Methods. 3 (12), 995-1000 (2006).</li><li>Alam, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proximity+Ligation+Assay+(PLA).">Proximity Ligation Assay (PLA).</a> Current Protocols in Immunology. 123 (1), 58 (2018).</li><li>Application Note 03: Growing Cells in &#181;-Channels. ibidi Available from: <a target="_blank" href="https://ibidi.com/img/cms/support/AN/AN03_Growing_cells.pdf">https://ibidi.com/img/cms/support/AN/AN03_Growing_cells.pdf</a> (2012)</li><li>Application Note 13: HUVECs under perfusion. ibidi Available from: <a target="_blank" href="https://ibidi.com/img/cms/support/AN/AN13_HUVECs_under_perfusion.pdf">https://ibidi.com/img/cms/support/AN/AN13_HUVECs_under_perfusion.pdf</a> (2019)</li><li>ibidi. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+Note+31:+Instructions+&#181;-Slide+VI+0.4.">Application Note 31: Instructions &#181;-Slide VI 0.4.</a> ibidi. , (2013).</li><li>Schindelin, 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=Fiji:+an+open-source+platform+for+biological-image+analysis.">Fiji: an open-source platform for biological-image analysis.</a> Nature Methods. 9 (7), 676-682 (2012).</li><li>Reichenbach, M., 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=Differential+impact+of+fluid+shear+stress+and+YAP/TAZ+on+BMP/TGF-&#946;+induced+osteogenic+target+genes.">Differential impact of fluid shear stress and YAP/TAZ on BMP/TGF-&#946; induced osteogenic target genes.</a> Advanced Biology. 5 (2), 2000051 (2021).</li><li>Hiepen, C., Mendez, P. L., Knaus, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=It+takes+two+to+tango:+Endothelial+TGF&#946;/BMP+signaling+crosstalk+with+mechanobiology.">It takes two to tango: Endothelial TGF&#946;/BMP signaling crosstalk with mechanobiology.</a> Cells. 9 (9), 1965 (2020).</li></ol>

这里描述的基于PLA的方案提供了一种有效的方法来确定暴露于剪切应力的EC中两种蛋白质的接近度（例如，它们的直接相互作用），具有定量和空间分辨率。通过使用具有多个平行通道的流动载玻片，可以在相同的机械条件下同时在细胞中检查几种不同的蛋白质相互作用。相比之下，定制的流室系统通常使用围绕玻璃盖玻片构建的单通道，这将只允许一个PLA实验，而无需每个滑块和泵的必要控制?...

转化生长因子β（TGFβ）超家族的蛋白质是多效性细胞因子，具有多种成员，包括TGFβ，骨形态发生蛋白（BMP）和Activins1，2。配体结合诱导受体低聚物的形成，导致磷酸化，从而激活细胞质调节性SMAD（R-SMAD）。根据配体的亚家族，激活不同的R-SMAD1，2。虽然TGFβs和激活素主要诱导SMAD2 / 3的磷酸化，但BMP诱导SMAD1 / 5 / 8磷酸化。然而，越来越多的证据表明，BMPs和TGFβs/Activins也激活了各自其他亚家族的R-SMAD，其过程称为"横向信号传导"3，4，5，6，7，8，并且存在由SMAD1 / 5和SMAD2 / 3组成的混合SMAD复合物，成员3，9.两个活化的R-SMAD随后与共同介质SMAD4形成三聚体复合物。然后，这些转录因子复合物能够易位到细胞核中并调节靶基因的转录。SMAD可以与各种不同的转录共激活剂和共抑制剂相互作用，从而导致调节靶基因的可能性多样化10。SMAD信号传导的放松管制对多种疾病都有严重影响。与此一致，不平衡的 TGFβ/BMP 信号传导可能导致严重的血管病变，例如肺动脉高压、遗传性出血性毛细血管扩张症或动脉粥样硬化3，11，12，13，14。
内皮细胞（EC）形成血管的最内层，因此暴露于剪切应力（SS），这是由血液粘性流动施加的摩擦力。有趣的是，居住在脉管系统部分的EC暴露于高水平的均匀层流SS，保持稳态和静止状态。相反，经历低、不均匀 SS 的 EC（例如，在主动脉弓的分叉或较小曲率处）会增殖并激活炎症通路15。反过来，功能失调的EC的部位容易发生动脉粥样硬化。有趣的是，这些动脉粥样硬化区域中的EC显示出异常高水平的激活SMAD2 / 3和SMAD1 / 516，17，18。在这种情况下，发现增强的TGFβ / BMP信号传导是动脉粥样硬化病变发展的早期事件19 ，并且发现对BMP信号传导的干扰可显着减少血管炎症，动脉粥样硬化形成和相关钙化20。
邻近连接测定（PLA）是一种原位研究蛋白质 - 蛋白质相互作用的生化技术21，22。它依赖于可以结合目标蛋白的不同物种抗体的特异性，从而允许在单细胞水平上高度特异性地检测内源性蛋白质相互作用。在这里，一抗必须在小于40nm的距离内与其靶表位结合，以允许检测23。因此，PLA与传统的共免疫沉淀方法相比非常有益，因为传统共免疫沉淀方法需要数百万个细胞来检测内源性蛋白质相互作用。在PLA中，物种特异性二抗与DNA片段共价连接（称为加号和减号探针），与一抗结合，如果感兴趣的蛋白质相互作用，加号和减号探针非常接近。DNA在下一步中结扎，并且使环状DNA的滚动圆扩增成为可能。在扩增过程中，荧光标记的互补寡核苷酸与合成的DNA结合，允许通过常规荧光显微镜观察这些蛋白质相互作用。
这里描述的方案使科学家能够使用PLA定量比较体 外 动脉粥样硬化保护和阿瑟罗普酮SS条件下活性SMAD转录复合物的数量。SS通过可编程气动泵系统产生，该系统能够产生定义水平的层流单向流量，并允许逐步增加流速。该方法允许检测SMAD1 / 5或SMAD2 / 3与SMAD4之间的相互作用，以及混合R-SMAD复合物。它可以很容易地扩展到分析SMAD与转录共调节因子的相互作用或SMAD以外的转录因子复合物。 图 1 显示了下面显示的协议的主要步骤。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/62608/62608fig01.jpg"> 图1：所描述的协议的示意图。 （A）接种在6通道载玻片中的细胞暴露于气动泵系统的剪切应力。（B）固定电池用于PLA实验或用于对照条件。（C）使用荧光显微镜获取PLA实验的图像，并使用ImageJ分析软件进行分析。 <a href="https://www.jove.com/files/ftp_upload/62608/62608fig01large.jpg" target="_blank">请点击此处查看此图的放大版本。</a>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>&#181;-Slide VI 0.4</td>
			<td>ibidi</td>
			<td>80606</td>
			<td>6-channel slide</td>
		</tr>
		<tr>
			<td>Ammonium Chloride</td>
			<td>Carl Roth</td>
			<td>K298.1</td>
			<td>Quenching</td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin</td>
			<td>Carl Roth</td>
			<td>8076.4</td>
			<td>Blocking</td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Sigma Aldrich/ Merck</td>
			<td>D9542</td>
			<td>Stain DNA/Nuclei</td>
		</tr>
		<tr>
			<td>DPBS</td>
			<td>PAN Biotech</td>
			<td>P04-53500</td>
			<td>PBS</td>
		</tr>
		<tr>
			<td>Duolink In Situ Detection Reagents Green</td>
			<td>Sigma Aldrich/ Merck</td>
			<td>DUO92014</td>
			<td>PLA kit containing Ligase, ligation buffer, polymerase and amplification buffer (with green labeled oligonucleotides)</td>
		</tr>
		<tr>
			<td>Duolink In Situ PLA Probe Anti-Mouse MINUS</td>
			<td>Sigma Aldrich/ Merck</td>
			<td>DUO92004</td>
			<td>MINUS probe</td>
		</tr>
		<tr>
			<td>Duolink In Situ PLA Probe Anti-Rabbit PLUS</td>
			<td>Sigma Aldrich/ Merck</td>
			<td>DUO92002</td>
			<td>PLUS probe</td>
		</tr>
		<tr>
			<td>Duolink In Situ Wash Buffers, Fluorescence</td>
			<td>Sigma Aldrich/ Merck</td>
			<td>DUO82049</td>
			<td>PLA wash buffers A and B</td>
		</tr>
		<tr>
			<td>Endothelial Cell Growth Supplement</td>
			<td>Corning</td>
			<td></td>
			<td>supplement for medium (ECGS)</td>
		</tr>
		<tr>
			<td>Fetal calf Serum</td>
			<td></td>
			<td></td>
			<td>supplement for medium</td>
		</tr>
		<tr>
			<td>FIJI</td>
			<td></td>
			<td></td>
			<td>Image Analysis software</td>
		</tr>
		<tr>
			<td>Formaldehyde solution 4% buffered</td>
			<td>KLINIPATH/VWR</td>
			<td>VWRK4186.BO1</td>
			<td>PFA</td>
		</tr>
		<tr>
			<td>Full medium</td>
			<td></td>
			<td></td>
			<td>M199 basal medium +20 % FCS +1 % P/S + 2 nM L-Glu +&#160; 25 &#181;g/mL Hep +&#160;&#160; 50 &#181;g/mL ECGS</td>
		</tr>
		<tr>
			<td>Gelatin from porcine skin, Type A</td>
			<td>Sigma Aldrich</td>
			<td>G2500</td>
			<td>Use 0.1% in PBS for coating of flow channels</td>
		</tr>
		<tr>
			<td>GraphPad Prism v.7</td>
			<td>GarphPad</td>
			<td></td>
			<td>Statistical Program used for the Plots and statistical calculations</td>
		</tr>
		<tr>
			<td>Heparin sodium salt from porcine intestinal mucosa</td>
			<td>Sigma Aldrich</td>
			<td>H4784-250MG</td>
			<td>supplement for medium (Hep)</td>
		</tr>
		<tr>
			<td>HUVECs</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ibidi Mounting Medium</td>
			<td>ibidi</td>
			<td>50001</td>
			<td>Liquid mounting medium</td>
		</tr>
		<tr>
			<td>ibidi Pump System</td>
			<td>ibidi</td>
			<td>10902</td>
			<td>pneumatic pump</td>
		</tr>
		<tr>
			<td>Leica TCS SP8</td>
			<td>Leica</td>
			<td></td>
			<td>confocal microscope</td>
		</tr>
		<tr>
			<td>L-Glutamin 200mM</td>
			<td>PAN Biotech</td>
			<td>P04-80100</td>
			<td>supplement for medium (L-Glu)</td>
		</tr>
		<tr>
			<td>Medium 199</td>
			<td>Sigma Aldrich</td>
			<td>M2154</td>
			<td>Base medium</td>
		</tr>
		<tr>
			<td>mouse anti- SMAD1 Antibody</td>
			<td>Abcam</td>
			<td>ab53745</td>
			<td>Suited for PLA</td>
		</tr>
		<tr>
			<td>mouse anti- SMAD2/3 Antibody</td>
			<td>BD Bioscience</td>
			<td>610843</td>
			<td>Not suited for PLA in combination with CST 9515</td>
		</tr>
		<tr>
			<td>mousee anti- SMAD4 Antibody</td>
			<td>Sanata Cruz Biotechnology</td>
			<td>sc-7966</td>
			<td>Suited for PLA</td>
		</tr>
		<tr>
			<td>Penicillin 10.000U/ml /Streptomycin 10mg/ml</td>
			<td>PAN Biotech</td>
			<td>P06-07100</td>
			<td>supplement for medium (P/S)</td>
		</tr>
		<tr>
			<td>Perfusion Set WHITE</td>
			<td>ibidi</td>
			<td>10963</td>
			<td>Tubings used for 1 dyn/cm2</td>
		</tr>
		<tr>
			<td>Perfusion Set YELLOW and GREEN</td>
			<td>ibidi</td>
			<td>10964</td>
			<td>Tubings used for 30 dyn/cm2</td>
		</tr>
		<tr>
			<td>rabbit anti- phospho SMAD1/5 Antibody</td>
			<td>Cell Signaling Technologies</td>
			<td>9516</td>
			<td>Suited for PLA</td>
		</tr>
		<tr>
			<td>rabbit anti- SMAD2/3 XP Antibody</td>
			<td>Cell Signaling Technologies</td>
			<td>8685</td>
			<td>Suited for PLA</td>
		</tr>
		<tr>
			<td>rabbit anti- SMAD4 Antibody</td>
			<td>Cell Signaling Technologies</td>
			<td>9515</td>
			<td>Not suited for PLA in combination with BD 610843</td>
		</tr>
		<tr>
			<td>Serial Connector for &#181;-Slides</td>
			<td>ibidi</td>
			<td>10830</td>
			<td>serial connection tubes</td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Carl Roth</td>
			<td>6683.1</td>
			<td>Permeabilization</td>
		</tr>
	</tbody>
</table>

visualization and quantification of tgf&#946;/bmp/smad signaling under different fluid shear stress conditions using proximity-ligation-assay

转化生长因子β（TGFβ）/骨形态发生蛋白（BMP）信号传导在脉管系统的发展和稳态期间受到严格调节和平衡因此，该信号通路中的失调导致严重的血管病变，例如肺动脉高血压，遗传性出血性毛细血管扩张症和动脉粥样硬化。内皮细胞（EC）作为血管的最内层，不断暴露于液体剪切应激（SS）。液体SS的异常模式已被证明可以增强TGFβ / BMP信号传导，其与其他刺激一起诱导动脉粥样硬化发生。与此相关，发现低层流SS的动脉粥样硬化素可以增强TGFβ / BMP信号传导，而动脉粥样硬化保护，高层流SS可以减少这种信号传导。为了有效地分析这些途径的激活，我们设计了一个工作流程，使用市售的气动泵系统和接近连接测定（PLA）研究在低层流SS和高层流SS条件下转录因子复合物的形成。
活性TGFβ / BMP信号传导需要形成由两个调节性SMAD（R-SMAD）组成的三聚体SMAD复合物;分别用于TGFβ和BMP信号传导的SMAD2 / 3和SMAD1 / 5 / 8，具有共同介质SMAD（co-SMAD;SMAD4）。使用PLA靶向三聚体SMAD复合物的不同亚基，即R-SMAD / co-SMAD或R-SMAD / R-SMAD，可以使用荧光显微镜定量和空间测量活性SMAD转录因子复合物的形成。
使用具有6个小平行通道的流动载玻片，可以串联连接，允许研究转录因子复合物的形成并包含必要的对照。 
这里解释的工作流程可以很容易地适应针对SMADs与其他转录因子或转录因子复合物的接近性的研究，在不同的流体SS条件下。本文介绍的工作流程展示了一种快速有效的方法，可以从定量和空间上研究EC中的流体SS诱导的TGFβ / BMP信号传导。

我们之前使用PLA来检测不同SMAD蛋白3 的相互作用，并分析了剪切应力引起的SMAD磷酸化变化28。
在这里，这两种方法都与上述协议相结合。将HUVECs置于1 dyn/cm2 和30 dyn/cm2 的剪切应力下，并分析SMAD转录因子的相互作用。我们表明，与高剪切应力（30 dyn / cm2）相比，低剪切应力（1 dyn / cm2）导致SMAD1-SMAD2 / 3相互作...

Watch this Scientific Journal Video about Visualization and Quantification of TGFÃŽÂ²/BMP/SMAD Signaling under Different Fluid Shear Stress Conditions using Proximity-Ligation-Assay at JoVE.com

Visualization and Quantification of TGFÃƒÅ½Ã‚Â²/BMP/SMAD Signaling under Different Fluid Shear Stress Conditions using Proximity-Ligation-Assay

在这里，我们建立了一个方案，使用暴露于病理和生理流体剪切应激条件下的内皮细胞中的接近连接测定（PLA）同时可视化和分析多个SMAD复合物。

使用接近-连接-测定法对不同流体剪切应力条件下TGFβ/BMP/SMAD信号传导的可视化和定量

Transforming Growth Factor &#946; (TGF&#946;)/Bone Morphogenetic Protein (BMP) signaling is tightly regulated and balanced during the development and ...

该协议使科学家能够定量比较不同剪切应激条件下转录因子复合物的数量，并且有利于血管生物学的研究。该协议的主要优点是使用微流体流道，允许同时研究多个抗体对，包括相应的对照。首先，通过将PBS中制备的0.1%猪皮明胶加入通道中，在37摄氏度下涂覆六通道载玻片30分钟。从明胶溶液中清空通道，并在预编码的六通道载玻片中以2.5倍10到每毫升第六个细胞的密度在30微升M199完整培养基中播种Huvecs。让细胞在37摄氏度下在加湿的培养箱中粘附一小时。向每个储液槽中加入60微升预先警告的M199完整培养基。在37摄氏度下将细胞在24小时后在加湿的培养箱中培养两天，并置换培养基。将硅管安装在流体单元上，用至少10毫升预先警告的M199完整介质填充储液罐。将带有管路的流体装置连接到泵系统，并在没有电池的情况下进行预运行，以平衡介质并去除任何剩余的空气。使用串行连接管连接六个通道滑道上的单个通道。将滑块上的第一个和最后一个通道连接到安装在流体装置上的管子。对于细胞暴露于高水平的纯粹应力，请通过适应阶段逐步增加纯粹应力，以每30分钟每平方厘米5个测功元的增量设置步进。在流体剪切应力暴露后，使用管道上的团块将载玻片从泵上拆下，避免培养箱中的介质溢出，并在冰上转移流动载玻片。将管道从储液槽中分离出来时，用手指关闭储液槽的另一侧，以避免将气泡困在通道中。保持流动在冰上滑动，小心地从储层中吸出培养基，而不是从细胞所在的通道吸出。将PBS加入一个储液槽中，用90微升冷无菌PBS洗涤样品，并从另一个储液槽中小心地吸出，然后对所有通道重复。通过将90微升缓冲的4%PFA溶液添加到添加PBS的同一储液槽中来固定细胞，并如图所示从另一个储液罐中吸出液体。将细胞固定在所有六个通道中后，将样品从冰转移到室温，并孵育20分钟。用PBS洗涤细胞三次，方法是将PBS添加到一个储液槽中，并在所有通道中小心地将其从另一个储液槽中吸出，注意不要使通道变干。通过将PBS中制备的90微升环境15毫摩尔氯化铵添加到其中一个储液槽中来淬火访问PFA。从另一个储液槽吸出并孵育细胞10分钟。通过在空储液器中加入在PBS中制备的90微升0.3%Triton X 100来透化细胞。从另一个储液槽吸出每个通道并孵育10分钟，然后如前所述用PBS洗涤三次。在90微升无菌PLA封闭溶液到一个储液器。从另一侧吸出每个通道，并在加湿室中以37摄氏度孵育一小时。在PLA抗体稀释剂和涡流中添加一抗。小心地从储液槽和通道中吸出阻塞溶液。在加入溶液的同时，通过倾斜载玻片，立即将30微升一抗溶液加入空通道中。对所有通道重复上述步骤，并在加湿室中以4摄氏度孵育过夜或在37摄氏度下孵育一小时。稀释减去兔和加小鼠PLA探针一至五的PLA抗体稀释剂。通过加入90微升洗涤缓冲液A并吸气来洗涤所有通道两次，如图所示。吸出洗涤缓冲液后，加入30微升PLA探针溶液，在加湿室中孵育。在D离子水中稀释连接缓冲液1至5，并在稀释的连接缓冲液中稀释一至40的莱格斯酶。洗涤并完全吸出洗涤缓冲液A后，在倾斜载玻片的同时向空通道中加入30微升连接溶液，并在加湿室中孵育。在去离子水中稀释扩增缓冲液一至五，然后在冰上稀释的扩增缓冲液中稀释一至80聚合酶。洗涤并完全吸出洗涤缓冲液A后，在倾斜载玻片的同时向空通道中加入30微升扩增溶液，并将其在加湿室中孵育。将DAPI稀释至500洗涤缓冲液B中，并通过加入90微升含有洗涤缓冲液B的DAPI并吸气以蒸煮细胞核来洗涤所有通道一次。然后用不含DAPI的洗涤缓冲液B洗涤所有通道一次。将洗涤缓冲液B在去离子水中稀释一至10，并用90微升稀释的洗涤缓冲液B洗涤所有通道一次.吸出洗涤缓冲液B后，立即向一个储液器中加入两到三滴液体安装介质，并倾斜载玻片以在所有通道中分布安装介质。将样品以四摄氏度储存在潮湿的环境中，直到成像。Huvecs暴露在高和低的纯粹压力下。低剪切应激增加了细胞质基质和细胞核中的SMAD蛋白相互作用。单抗体对照显示的信号很少，证明了实验的成功。抗体浓度的增加导致每个细胞的PLA事件数量增加，但高纯度和低纯度暴露细胞之间的PLA信号差异减小。用于封闭和抗体稀释的自制缓冲液可用作商业缓冲液的替代品。对PLA事件进行商业和自制稀释剂和阻断溶液的定量，在胞质和核区域显示出相同的PLA信号模式。然而，使用商业解决方案时，每个细胞的PLA事件总数更高。SMAD Two/Three，SMAD Four抗体的组合用于SMAD Four抗体不适合免疫荧光实验的地方。在实验性与对照条件下，PLA事件没有差异，表明选择正确的抗体组合检测PLA事件的重要性。所描述的方案可以适应于检测与SMAD不同的转录因子复合物的相互作用，因此有助于理解易发生和动脉粥样硬化保护条件下的基因调控。

Research

JoVE Journal

Biochemistry

Visualization and Quantification of TGF&#946;/BMP/SMAD Signaling under Different Fluid Shear Stress Conditions using Proximity-Ligation-Assay

Quantification of Bacterial Histidine Kinase Autophosphorylation Using a Nitrocellulose Binding Assay

使用硝酸纤维素结合分析细菌组氨酸激酶自身磷酸化的定量分析

We demonstrate a useful method for quantifying autophosphorylation of purified bacterial histidine kinases. Histidine kinases are known for their ...

科研

生物化学

Visualization of Protein-protein Interaction in Nuclear and Cytoplasmic Fractions by Co-immunoprecipitation and In Situ Proximity Ligation Assay

Visualization of Protein-protein Interaction in Nuclear and Cytoplasmic Fractions by Co-immunoprecipitation and In Situ Proximity Ligation Assay

通过免疫共沉淀在核质馏分蛋白质相互作用的可视化和<em&gt;原位</em&gt;接近结扎分析

Protein-protein interactions are involved in thousands of cellular processes and occur in distinct spatial context. Traditionally, co-immunoprecipitation ...

Hydrolysis of a Ni-Schiff-Base Complex Using Conditions Suitable for Retention of Acid-labile Protecting Groups

镍 - 席夫碱的水解复杂环境条件适宜酸不稳定保护基团的保留

Unnatural amino acids, amino acids containing side-chain functionalities not commonly seen in nature, are increasingly found in synthetic peptide ...

Detection and Visualization of DNA Damage-induced Protein Complexes in Suspension Cell Cultures Using the Proximity Ligation Assay

检测和可视化DNA损伤诱导的蛋白质复合物悬浮细胞培养使用邻近连接测定

The DNA damage response orchestrates the repair of DNA lesions that occur spontaneously, are caused by genotoxic stress, or appear in the context of ...

Detection of Heterodimerization of Protein Isoforms Using an in Situ Proximity Ligation Assay

Detection of Heterodimerization of Protein Isoforms Using an in Situ Proximity Ligation Assay

原位近接结扎法检测蛋白异构体的 Heterodimerization

Regulated protein-protein interactions are a guiding principle for many signaling events, and the detection of such events is an important element in ...

Calibration-free In Vitro Quantification of Protein Homo-oligomerization Using Commercial Instrumentation and Free, Open Source Brightness Analysis Software

Calibration-free In Vitro Quantification of Protein Homo-oligomerization Using Commercial Instrumentation and Free, Open Source Brightness Analysis Software

利用商用仪器和自由开源亮度分析软件对蛋白质的聚齐聚进行无标定的体外定量化

Number and brightness is a calibration-free fluorescence fluctuation spectroscopy (FFS) technique for detecting protein homo-oligomerization. It can be ...

Quantification of Hypopigmentation Activity In Vitro

低聚活性的体外定量

This study presents laboratory methods for the quantification of hypopigmentation activity in vitro. Melanin, the major pigment in melanocytes, is ...

Quantification of Protein Interaction Network Dynamics using Multiplexed Co-Immunoprecipitation

使用多路复用共免疫沉淀对蛋白质相互作用网络动力学进行量化

Dynamic protein-protein interactions control cellular behavior, from motility to DNA replication to signal transduction. However, monitoring dynamic ...

Medium Preparation for the Cultivation of Microorganisms under Strictly Anaerobic/Anoxic Conditions

严格厌氧/缺氧条件下微生物培养的介质制备

In contrast to aerobic organisms, strictly anaerobic microorganisms require the absence of oxygen and usually a low redox potential to initiate growth. As ...

Quantification of Coenzyme A in Cells and Tissues

细胞和组织中辅酶A的定量

Emerging research has revealed that the cellular coenzyme A (CoA) supply can become limiting with a detrimental impact on growth, metabolism and survival. ...