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Method Article
We describe here a protocol for the generation of iCMs using retrovirus-mediated delivery of Gata4, Tbx5 and Mef2c in a polycistronic construct. This protocol yields a relatively homogeneous population of reprogrammed cells with improved efficiency and quality and is valuable for future studies of iCM reprogramming.
心脏成纤维细胞(CFS)成心肌细胞诱导直接转化(ICMS),通过治疗心脏疾病提供替代战略保持着再生医学的巨大潜力。这个转换已通过确定的因子如GATA4(G),MEF2C(M)和Tbx5中(T)的强制表达来实现。传统上,ICMS是由病毒表达这些个人因素鸡尾酒产生。然而,重新编程的效率是相对低的,大部分的体外 G,M,T转导的成纤维细胞不成为完全重新编程,使得难以研究的重编程机制它。我们最近已经表明,G,M的化学计量,T是用于有效ICM重新编程的关键。 G,M,T的具有M和低水平的G和T的通过使用我们的多顺反子MGT向量(以下称为MGT)显著增加重新编程的效率达到了较高水平的最佳化学计量学和体外改善ICM质量。在这里,我们提供用于产生ICMS与从心脏成纤维细胞MGT构建体的方法的详细描述。心脏成纤维细胞,代病毒重编程和重编程过程的评价的隔离也包括以提供有效和可再现代ICMS的一个平台。
Cardiovascular disease remains the leading cause of death worldwide, accounting for 17.3 million deaths per year1. Loss of cardiomyocytes resulting from myocardial infarction (MI) or progressive heart failure is a major cause of morbidity and mortality2. Due to limited regenerative capacity, adult mammalian hearts usually suffer from impaired pump function and heart failure following injury3-6. As such, efficient (re)generation of cardiomyocytes in vivo and in vitro for treatment of heart disease and for disease modeling is a critical issue needing to be addressed.
Recent development of direct reprogramming, which directly reprograms cells from one differentiated phenotype to another without transitioning through the pluripotent state, offers a promising alternative approach for regenerative medicine. The mammalian heart contains abundant cardiac fibroblasts (CFs), which account for approximately half of the cells in heart and massively proliferate upon injury7-9. Thus, the vast pool of CFs could serve as an endogenous source of new CMs for regenerative therapy if they could be directly reprogrammed into functional CMs. It has been shown that a combination of transcription factors, such as Gata4 (G), Mef2c (M) and Tbx5 (T), with or without microRNAs or small molecules can reprogram fibroblasts into iCMs10-26. Importantly, this conversion can also be induced in vivo, and results in an improvement in cardiac function and a reduction in scar size in an infarcted heart16,27-29. These studies indicate that direct cardiac reprogramming may be a potential avenue to heal an injured heart. However, the low efficiency of iCM reprogramming has become a major hurdle for further mechanistic studies. In addition, the reproducibility of cardiac reprogramming is another controversial issue of this technology11,30,31.
Very recently, we generated a complete set of polycistronic constructs encoding G,M,T in all possible splicing orders with identical 2A sequences in a single mRNA. These polycistronic constructs yielded varied G, M and T protein expression levels, which led to significantly different reprogramming efficiency25. The most efficient construct, named MGT, which showed a relatively high Mef2c and low Gata4 and Tbx5 expression, significantly improved reprogramming efficiency and produced large amounts of iCMs with CM markers expression, robust calcium oscillation and spontaneous beating25. Moreover, by using MGT polycistronic construct, our study avoided the use of multiple vectors and generated cells with homogenous expression ratio of G,M,T, thus providing an improved platform for cardiac reprogramming research. To increase experimental reproducibility, here we describe in detail how to isolate fibroblasts, produce retrovirus carrying MGT cassette, generate iCMs and evaluate the reprogramming efficiency.
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这里列出的协议采用新生小鼠。动物保健和实验是按照由科实验室的动物医学(DLAM)北卡罗来纳大学教堂山分校制定的准则进行。
1.准备缓冲区和媒体
2.代新生小鼠心肌成纤维细胞
3.逆转录病毒生成的ICM重新编程
注意:执行在无菌条件下在一个BSL2生物安全柜以下步骤。妥善处置转染的细胞,吸头和管道的建议,以避免对环境和健康危害的风险。
4.重编程心脏成纤维细胞
重编程效率5.免疫细胞化学分析
重编程效率的6流式细胞仪分析
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重新编程步骤在图1中总结的示意图。MGT转导后,在重新编程的细胞的GFP表达可以早在第3天嘌呤选择转导的细胞的从第3天开始,并在头两个星期保持检测如果PMX-普罗-MGT构建体被使用。在第10天至14天,心肌标记物像cTnT和αActinin的表达可以由两个IC卡(图2B,步骤5)和FACS(图2A,步骤6)被检测到,这表明起始成纤维细胞正在经历重编程朝向心脏细胞命运。
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对于成功的ICM代使用此协议时,存在具有对整体效率产生影响的几个重要因素。尤其在开始成纤维细胞的条件和逆转录病毒编码MGT的质量可以极大地影响重编程效率。
产生的成纤维细胞作为新鲜健康尽可能是重要的。外植体培养方法,成纤维细胞可用于前外植七天后铺于菜肴。酶消化法,成纤维细胞,可以早在隔离的次日使用。冻结或传代的成纤维细胞进行重新编程,不推?...
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The authors have nothing to disclose.
We are grateful for expert technical assistance from the UNC Flow Cytometry Core and UNC Microscopy Core. We thank members of the Qian lab and the Liu lab for helpful discussions and critical reviews of the manuscript. This study was supported by NIH/NHLBI R00 HL109079 grant to Dr. Liu and American Heart Association (AHA) Scientist Development Grant 13SDG17060010 and the Ellison Medical Foundation (EMF) New Scholar Grant AG-NS-1064-13 to Dr. Qian.
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Name | Company | Catalog Number | Comments |
anti-cardiac troponin T | Thermo Scientific | MS-295-PO | 1:200 for FACS and 1:400 for ICC |
anti-GFP | Life Technologies | A11122 | 1:500 for both FACS and ICC |
anti- aActinin | Sigma-Aldrich | A7811 | 1:500 for both FACS and ICC |
anti-Connexin43 | Sigma-Aldrich | C6219 | 1:500 for ICC |
anit-Mef2c | Abcam | ab64644 | 1:1,000 for ICC |
anti-Gata4 | Santa Cruz Biotechnology | sc-1237 | 1:200 for ICC |
anti-Tbx5 | Santa Cruz Biotechnology | sc-17866 | 1:200 for ICC |
Alexa Fluor 488–conjugated donkey anti-rabbit IgG | Jackson ImmunoResearch Inc | 711-545-152 | 1:500 for both FACS and ICC |
Alexa Fluor 647–conjugated donkey anti-mouse IgG | Jackson ImmunoResearch Inc | 715-605-150 | 1:500 for both FACS and ICC |
Cytofix/Cytoperm kit for intracellular staining | BD Biosciences | 554722 | |
Rhod-3 Calcium Imaging Kit | Life Technologies | R10145 | |
Thy1.2 microbeads | Miltenyi Biotec | 130-049-101 | |
Vectashield solution with DAPI | Vector labs | H-1500 | |
FBS | Sigma-Aldrich | F-2442 | |
Trypsin-EDTA (0.05%) | Corning | 25-052 | |
PRMI1640 medium | Life Technologies | 11875-093 | |
B27 supplement | Life Technologies | 17504-044 | |
IMDM | Life Technologies | 12440-053 | |
Opti-MEM Reduced Serum Medium | Life Technologies | 31985-070 | |
M199 medium | Life Technologies | 10-060 | |
DMEM, high glucose | Life Technologies | 10-013 | |
Penicillin-streptomycin | Corning | 30-002 | |
Non-essential amino acids | Life Technologies | 11130-050 | |
Lipofectamine 2000 | Life Technologies | 11668500 | |
blasticidin | Life Technologies | A11139-03 | |
puromycin | Life Technologies | A11138-03 | |
Collagenase II | Worthington | LS004176 | |
polybrene | Millipore | TR-1003-G | |
Triton X-100 | Fisher | BP151-100 | |
CaCl2 | Sigma-Aldrich | C7902 | |
HEPES | Sigma-Aldrich | H4034 | |
NaCl | Sigma-Aldrich | BP358-212 | |
KCl | Sigma-Aldrich | PX1405 | |
Na2HPO4 | Sigma-Aldrich | S7907 | |
Glucose | Sigma-Aldrich | G6152 | |
Bovine serum albumin | Fisher | 9048-46-8 | |
paraformaldehyde | EMS | 15714 | |
Retrovirus Precipitation Solution | ALSTEM | VC-200 | |
0.4% Trypan blue solution | Sigma-Aldrich | T8154 | |
gelatin | Sigma-Aldrich | G1393 | |
Dulbecco's PBS without CaCl2 and MgCl2 (D-PBS, 1x) | Sigma-Aldrich | D8537 | |
HBSS (Hanks Balanced Salt Solution) | Corning | 21022 | |
LS column | Miltenyi Biotec | 130-042-401 | |
0.45 μm cellulose acetate filter | Thermo Scientific | 190-2545 | |
24-well plates | Corning | 3524 | |
10 cm Tissue culture dishes | Thermo Scientific | 172958 | |
60 mm center well culture dish | Corning | 3260 | |
96 Well Clear V-Bottom 2 ml Polypropylene Deep Well Plate | Denville Scientific | P9639 | |
Polystyrene round-bottom tubes with cell-strainer cap | BD Biosciences | 352235 | |
Centrifuge | Eppendorf | 5810R | |
Vortexer MINI | VWR | 58816-121 | |
EVOS FL Auto Cell Imaging System | Life Technologies | AMAFD1000 | |
MACS MultiStand | Miltenyi Biotec | 130-042-303 | |
MidiMACS Separator | Miltenyi Biotec | 130-042-302 | |
Round glass cover slip | Electron Microscopy Sciences | 72195-15 |
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