用3D-FRAP显微镜分析miRNA的间隙连接依赖性转移
Summary
在这里，我们描述了光漂白后三维荧光恢复（3D-FRAP）的应用，用于分析miRNA的间隙连接依赖穿梭。与通常应用的方法相比，3D-FRAP允许实时定量小RNA的细胞间转移，具有高的时空分辨率。
Abstract
小反义RNA（如miRNA和siRNA）在细胞生理学和病理学中起重要作用，而且可用作治疗几种疾病的治疗剂。开发miRNA / siRNA治疗新的创新策略是基于对基础机制的广泛了解。最近的数据表明，小细胞以间隙连接依赖的方式在细胞之间进行交换，从而在受体细胞中诱导基因调控作用。分子生物学技术和流式细胞仪分析通常用于研究miRNA的细胞间交换。然而，这些方法不提供高的时间分辨率，这在研究分子的间隙连接通量时是必需的。因此，为了研究miRNA / siRNA作为细胞间信号分子的影响，需要新的工具，这将允许在细胞水平上分析这些小RNA。本协议描述了ap光漂白后三维荧光恢复（3D-FRAP）显微镜的澄清，以阐明心脏细胞之间的miRNA分子的间隙连接依赖性交换。重要的是，这种直接和非侵入性的活细胞成像方法允许实时荧光标记的小RNA的间隙连接穿梭的可视化和定量，具有高的时空分辨率。通过3D-FRAP获得的数据证实了细胞间基因调控的新途径，其中小RNA作为细胞间网络内的信号分子。
Introduction
小的非编码RNA是细胞基因调控的重要参与者。这些分子由与特异性靶mRNA结合的20-25个核苷酸组成，导致翻译的阻断或mRNA降解1,2 。由小RNA（例如miRNA和siRNA）进行的基因调控过程是许多不同物种中发现的高度保守的机制。特别地，miRNA分子对多种生理过程至关重要，包括增殖，分化和再生4,5 。此外，miRNA表达的失调归因于许多病理学障碍。相应地，miRNA已经被证明适合作为诊断的生物标志物和用作基因治疗的治疗剂6,7 </suP>。
间隙连接（GJs）是两个相邻细胞的质膜中的专门的蛋白质结构，允许分子量高达1kD的扩散交换。已被证明对于组织发育，分化，细胞死亡和病理性疾病如癌症或心血管疾病8,9,10很重要 。已经描述了几个分子能够穿过GJ通道，包括离子，代谢物和核苷酸。有趣的是，还发现GJs为小RNA 11,12的细胞间移动提供了途径。因此，miRNA不仅可以在其产生的细胞内，而且在受体细胞内起作用。这突出了miRNA在细胞间信号转导系统中的作用。同时，数据显示该间隙连接细胞间通讯与miRNA功能密切相关。由于miRNA和GJs对组织稳态，病理学和诊断的重大影响，全面了解GJs的功能和miRNA的相关细胞间动力学有助于阐明基于miRNA的疾病的机制，并制定新的策略miRNA疗法。
根据间隙连接耦合的程度，miRNA分子在细胞间的转移可以是非常快速的过程。因此，需要一种允许可视化和量化这些调节信号分子的快速细胞间移动的方法。通常，已经应用流式细胞术和分子生物学技术来证明小RNA的穿梭11,12,13,14。然而，与FRAP微观相反复制，这些方法缺乏高时间分辨率，这是通过GJs分析miRNA的交换时强制的。此外，FRAP显微镜侵入性较小，因此代表了一种功能强大且新颖的活细胞成像技术，用于评估几种15,16,17型细胞中分子的GJ依赖性交换。
在这里，我们提出了一个详细的协议，描述了3D-FRAP应用于评估心肌细胞之间的miRNA穿梭。为此，用荧光标记的miRNA转染心肌细胞。用该miRNA标记的细胞被光漂白，并且以时间依赖的方式记录来自相邻细胞的间隙连接miRNA再流入。 FRAP实验的高时间分辨率提供了进行动力学研究以准确评估活细胞之间的miRNA和siRNA的细胞间转移的可能性。 Moreo由于小RNA可以通过具有高度不同动力学的不同机制进行交换，FRAP显微镜可以帮助澄清GJ在相应的穿梭过程18中涉及的程度。此外，3D-FRAP可用于研究GJ通透性的生理和病理学改变及其对小RNA转移的影响15,19。
Protocol
Representative Results
Discussion
miRNA是细胞生理学中的关键参与者，并被证明通过使用G_s作为细胞间交换途径，作为信号分子11,12,22。目前的方案提出体外活细胞成像技术来表征使用荧光miRNA在细胞簇内的GJ依赖性穿梭。
该方案作为细胞模型系统在心肌细胞上开发。然而，如果电穿孔是miRNA转染的合适方法，则该方法可以应用于几种细胞类型。除了细胞间细胞交换，所提出的技术也适用于研究miRNA?…
Disclosures
The authors have nothing to disclose.
Acknowledgements
德国联邦教育和研究部（FKZ 0312138A和FKZ 316159），梅克伦堡 – 西波美拉尼亚与欧盟结构基金（ESF / IVWM-B34-0030 / 10和ESF / IVBM-B35-0010 / 12），DFG（DA1296-1）和德国心脏基金会（F / 01/12）。此外，RD由罗斯托克大学医学中心（889001），DAMP基金会和BMBF（VIP + 00240）的FORUN计划支持。
Materials
| neonatal NMRI mice | Charles River | ||
| Gelatin | Sigma Aldrich | G7041 | 0.1% solution in PBS, sterilized |
| PBS | Pan Biotech | P04-53500 | |
| Dulbecco´s modified medium | Pan Biotech | P04-03550 | |
| Penicillin/Streptomycin | Thermo Fisher Scientific | 15140122 | 100 U/ml, 100µg/ml |
| Fetal bovine serum | Pan Biotech | P30-3306 | |
| Cell culture plastic | TPP | ||
| Primary Cardiomyocyte Isolation Kit | Thermo Fisher Scientific | 88281 | |
| HBSS | Thermo Fisher Scientific | 88281 | included in primary cardiomyocyte isolation kit |
| Trypan blue | Thermo Fisher Scientific | 15250061 | |
| miRIDIAN Dy547 labeled microRNA Mimic | Dharmacon | CP-004500-01-05 | dissolve in RNAse free water, stock solution 20µM |
| Sodium phosphate monobasic | Sigma | S3139 | |
| Sodium phosphate dibasic | Carl Roth | T877.2 | |
| Potassium chloride | Sigma | P9333 | |
| Magnesium chloride | Serva | 28305.01 | |
| Sodium succinate | Carl Roth | 3195.1 | |
| 0.05% Trypsin/EDTA solution | Merck | L2153 | |
| 4-well- Glass bottom chamber slides | IBIDI | 80827 | coat with 0.1% gelatin solution |
| Amaxa Nucleofector II | Lonza | program G-009 was used for Electroporation | |
| LSM 780 ELYRA PS.1 system | Zeiss | ||
| Excel software | Microsoft | ||
| α-actinin antibody | Abcam | ab9465 | dilution 1:200 |
| Connexin43 antibody | Santa Cruz | sc-9059 | dilution 1:200 |
| goat anti-mouse Alexa 594 antibody | Thermo Fisher Scientific | A-11005 | dilution 1:300 |
| goat anti-rabbit Alexa 488 antibody | Thermo Fisher Scientific | A-11034 | dilution 1:300 |
| Connexin43 siRNA | Thermo Fisher Scientific | AM16708 ID158724 | final concentration 250nM |
| Near-IR Live/Dead Cell Stain Kit | Thermo Fisher Scientific | L10119 | |
| CellTrace Calcein Red-Orange | Thermo Scientific | C34851 | |
| DAPI nuclear stain | Thermo Scientific | D1306 |
References
- Carthew, R. W., Sontheimer, E. J. Origins and Mechanisms of miRNAs and siRNAs. Cell. 136 (4), 642-655 (2009).
- Fire, A., Xu, S., Montgomery, M. K., Kostas, S. A., Driver, S. E., Mello, C. C. Potent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans. Nature. 391 (6669), 806-811 (1998).
- Grimm, D. Small silencing RNAs: state-of-the-art. Adv Drug Deliv Rev. 61 (9), 672-703 (2009).
- Raghunathan, S., Patel, B. M. Therapeutic implications of small interfering RNA in cardiovascular diseases. Fundam Clin Pharmacol. 27 (1), 1-20 (2013).
- Sluijter, J. P. G. MicroRNAs in Cardiovascular Regenerative Medicine: Directing Tissue Repair and Cellular Differentiation. ISRN Vasc Med. , 1-16 (2013).
- Li, M., Zhang, J. Circulating MicroRNAs: Potential and Emerging Biomarkers for Diagnosis of Cardiovascular and Cerebrovascular Diseases. Biomed Res Int. , 1-9 (2015).
- Romaine, S. P. R., Tomaszewski, M., Condorelli, G., Samani, N. J. MicroRNAs in cardiovascular disease: an introduction for clinicians. Heart. 101 (12), 921-928 (2015).
- Maes, M., Crespo Yanguas, ., Willebrords, S., Cogliati, J., Vinken, B., M, Connexin and pannexin signaling in gastrointestinal and liver disease. Transl Res. 166 (4), 332-343 (2015).
- Michela, P., Velia, V., Aldo, P., Ada, P. Role of connexin 43 in cardiovascular diseases. Eur. J. Pharmacol. 768, 71-76 (2015).
- Naus, C. C., Laird, D. W. Implications and challenges of connexin connections to cancer. Nat Rev Cancer. 10 (6), 435-441 (2010).
- Hong, X., Sin, W. C., Harris, A. L., Naus, C. C. Gap junctions modulate glioma invasion by direct transfer of microRNA. Oncotarget. 6 (17), 15566-15577 (2015).
- Lee, H. K. H., et al. Mesenchymal stem cells deliver synthetic microRNA mimics to glioma cells and glioma stem cells and inhibit their cell migration and self-renewal. Oncotarget. 4 (2), 346-361 (2013).
- Katakowski, M., Buller, B., Wang, X., Rogers, T., Chopp, M. Functional microRNA is transferred between glioma cells. Cancer Res. 70 (21), 8259-8263 (2010).
- Zong, L., Zhu, Y., Liang, R., Zhao, H. -. B. Gap junction mediated miRNA intercellular transfer and gene regulation: A novel mechanism for intercellular genetic communication. Sci Rep. 6, 19884 (2016).
- Yum, S. W., Zhang, J., Scherer, S. S. Dominant connexin26 mutants associated with human hearing loss have trans-dominant effects on connexin30. Neurobiol Dis. 38 (2), 226-236 (2010).
- Kuzma-Kuzniarska, M., Yapp, C., Pearson-Jones, T. W., Jones, A. K., Hulley, P. A. Functional assessment of gap junctions in monolayer and three-dimensional cultures of human tendon cells using fluorescence recovery after photobleaching. J Biomed Opt. 19 (1), 15001 (2013).
- Lemcke, H., Nittel, M. -. L., Weiss, D. G., Kuznetsov, S. A. Neuronal differentiation requires a biphasic modulation of gap junctional intercellular communication caused by dynamic changes of connexin43 expression. Eur J Neurosci. 38 (2), 2218-2228 (2013).
- Lemcke, H., Steinhoff, G., David, R. Gap junctional shuttling of miRNA – A novel pathway of intercellular gene regulation and its prospects in clinical application. Cell Signal. 27 (12), 2506-2514 (2015).
- Lemcke, H., Kuznetsov, S. A. Involvement of connexin43 in the EGF/EGFR signalling during self-renewal and differentiation of neural progenitor cells. Cell Signal. 25 (12), 2676-2684 (2013).
- Lemcke, H., Peukert, J., Voronina, N., Skorska, A., Steinhoff, G., David, R. Applying 3D-FRAP microscopy to analyse gap junction-dependent shuttling of small antisense RNAs between cardiomyocytes. J. Mol. Cell. Cardiol. 98, 117-127 (2016).
- Laupheimer, M., et al. Selective Migration of Subpopulations of Bone Marrow Cells along an SDF-1 α and ATP Gradient. Bone Marrow Res. , 1-10 (2014).
- Zhang, S., Wang, Q., Liu, L., Hong, X., Zhang, Y., Tao, L. Gap junctions enhance the antiproliferative effect of microRNA-124-3p in glioblastoma cells. J Cell Physiol Physiol. 230 (10), 2476-2488 (2015).
- Vasilescu, C., Tanase, M., Dragomir, M., Calin, G. A. From mobility to crosstalk. A model of intracellular miRNAs motion may explain the RNAs interaction mechanism on the basis of target subcellular localization. Math Biosci. 280, 50-61 (2016).
- Pitchiaya, S., Androsavich, J. R., Walter, N. G. Intracellular single molecule microscopy reveals two kinetically distinct pathways for microRNA assembly. EMBO Rep. 13 (8), 709-715 (2012).
- Heinze, K. G., Costantino, S., De Koninck, P., Wiseman, P. W. Beyond photobleaching, laser illumination unbinds fluorescent proteins. J Phys Chem B. 113 (15), 5225-5233 (2009).
- Jou, M. J., Jou, S. B., Guo, M. J., Wu, H. Y., Peng, T. I. Mitochondrial reactive oxygen species generation and calcium increase induced by visible light in astrocytes. Ann N Y Acad Sci. 1011, 45-56 (2004).
- Dong, H., Lei, J., Ding, L., Wen, Y., Ju, H., Zhang, X. MicroRNA: Function, detection, and bioanalysis. Chem Rev. 113 (8), 6207-6233 (2013).
- Liang, Y., Ridzon, D., Wong, L., Chen, C. Characterization of microRNA expression profiles in normal human tissues. BMC Genomics. 8 (1), 166 (2007).
- Mittelbrunn, M., et al. Unidirectional transfer of microRNA-loaded exosomes from T cells to antigen-presenting cells. Nat Commun. 2, 282 (2011).
- Squadrito, M. L., et al. Endogenous RNAs Modulate MicroRNA Sorting to Exosomes and Transfer to Acceptor Cells. Cell Rep. 8, 1432-1446 (2014).
- Zhang, B., Farwell, M. A. microRNAs: a new emerging class of players for disease diagnostics and gene therapy. J Cell Mol Med. 12 (1), 3-21 (2008).
- Chen, Y., Gao, D. -. Y., Huang, L. In vivo delivery of miRNAs for cancer therapy: Challenges and strategies. Adv Drug Deliv Rev. 81C, 128-141 (2015).
