This protocol allows for the reliable generation and characterization of blood outgrowth endothelial cells (BOECs) from a small volume of adult peripheral blood. BOECs can be used as a surrogate for endothelial cells from patients with vascular disorders and as a substrate for the generation of induced pluripotent stem cells.
Historically, the limited availability of primary endothelial cells from patients with vascular disorders has hindered the study of the molecular mechanisms underlying endothelial dysfunction in these individuals. However, the recent identification of blood outgrowth endothelial cells (BOECs), generated from circulating endothelial progenitors in adult peripheral blood, may circumvent this limitation by offering an endothelial-like, primary cell surrogate for patient-derived endothelial cells. Beyond their value to understanding endothelial biology and disease modeling, BOECs have potential uses in endothelial cell transplantation therapies. They are also a suitable cellular substrate for the generation of induced pluripotent stem cells (iPSCs) via nuclear reprogramming, offering a number of advantages over other cell types. We describe a method for the reliable generation, culture and characterization of BOECs from adult peripheral blood for use in these and other applications. This approach (i) allows for the generation of patient-specific endothelial cells from a relatively small volume of adult peripheral blood and (ii) produces cells that are highly similar to primary endothelial cells in morphology, cell signaling and gene expression.
直到最近,产后代新血管被认为是通过被称为血管生成的方法,定义为从预先存在血管内皮细胞的新血管的萌发发生完全。1本过程形成鲜明对比的血管,或从头形成血管内皮前体细胞,这被认为胚胎发育过程中发生的专门2然而,最近的研究已经鉴定和分离在成人的外周血循环内皮祖细胞(EPCs)。这些细胞具有分化成成熟的内皮细胞在培养的能力,被认为参与产后血管。3,4-
协议用于分离和扩增这些内皮祖细胞通常涉及含有内皮细胞生长因子,包括vascul外周血单核细胞(外周血单个核细胞)中的媒体的培养芳内皮生长因子(VEGF)和成纤维细胞生长因子-2 5-8 EPC培养产生各种显着不同的细胞类型。初始培养物(<7天)由单核细胞类型,在文献中被称为“早”内皮祖细胞主导。尽管他们的名字,这些细胞表达单核细胞标志物CD14,是阴性的祖标志物CD34和表达经典内皮细胞标志物CD31和血管内皮生长因子受体2(VEGFR2)的唯一的最低水平。5续文化产生了细胞的二次人口,称为晚期生长内皮祖细胞或血长出内皮细胞(BOECs),其中出现的内皮样细胞为谨慎菌落。不同的是单核细胞早期内皮祖细胞,BOECs,这也被称为内皮细胞集落形成细胞(ECFCs),生长内皮细胞或后期生长的内皮细胞,表现出鹅卵石形态即是典型的内皮细胞单层,并在表面标志高度相似5和基因表达9到成熟内皮细胞。
从外周血内皮样细胞的产生提供了几个优点,特别是对于的内皮细胞功能障碍与血管疾病例如肺动脉高压(PAH)10,或血管性血友病11之前BOECs的可用性,内皮相关的研究细胞只能来自于植器官的死亡或器官移植,或隔离的时间从脐静脉出生。这种减小的可用性是一个严重的限制,以从患者的心血管疾病,以及内皮细胞和任何血细胞或壁细胞之间的相互作用的理解内皮细胞生物学。此外,分离和这些来源的培养的内皮细胞的一个纯人口在技术上是挑战性和由这些方法获得的细胞具有仅一个LIMITEð增殖能力。因此BOECs提供有价值替代物源自患者的原代内皮细胞的分离和培养。
除了 它们在体外应用 ,BOECs,可以在自体细胞移植疗法可能有用。这些应用包括内皮细胞移植,以促进新血管形成(见12和其中的参考文献),以及诱导的多能干细胞的产生(iPS细胞)。13 BOEC衍生的iPSC可用于疾病建模,并提供巨大潜力作为出发材料为自体细胞治疗。 BOECs重新编程更快,具有更高的效率比皮肤成纤维细胞。此外,BOECs还允许iPSCs的是自由核型异常,这是任何技术,就可以适于平移应用的基本的特征的产生。以产生从患者血液样品中的iPSCs的能力LSO省去了皮肤活检和皮肤成纤维细胞的产生,从而促进细胞的产生,从患者的伤口愈合障碍,或非常年轻。
下面详细说明该协议,批准,并按照国家研究伦理服务委员会(英格兰东部)的指导方针进行,提供了简单可靠的方法BOECs的一代从一个相对小的体积大于90%的效率(60外周血毫升)。这些细胞是高度增殖性和可反复传代,允许亿万细胞从单个血样的产生。
We present a detailed protocol that allows for the robust and efficient derivation of BOECs from adult peripheral blood mononuclear cells (PBMNCs). Our protocol includes two important refinements that represent advances on previous methods of BOEC isolation.14-16 These include the absence of heparin in the initial PBMNC culture medium and the use of defined, embryonic stem cell-qualified serum. This latter refinement is of particular importance. Embryonic stem cell (ESC)-qualified serum is a more consistent grade of serum and, although it is not known yet what component(s) are enriched in the serum that benefit BOEC isolation, the impact of this defined serum on the efficiency of BOEC generation is clear in our hands. In addition, we have also had success in isolating BOECs using human serum, thereby allowing for the generation of BOECs for clinical translation. In our hands, this refined protocol results in the successful isolation of stable BOEC cultures from greater than 90% of donors, making it one of the most reliable BOEC generation methods reported thus far. Although the use of particular sera is critical to BOEC generation, it also represents a primary limitation of the current protocol. Future improvements to the technique could include the generation of these cells in serum-free, defined culture conditions.
Critical Steps in the protocol include processing blood samples as soon as possible after collection, complete harvesting of the buffy coat cells after density gradient centrifugation and the timely passaging of initial colonies from P0 to P1. This passaging step is critical to establishment of a stable isolation. Like other endothelial cells, BOECs appear to be very sensitive to plating density. If the plating density after passaging is too low, the BOECs will not proliferate. Conversely, if the colonies are allowed to become overconfluent before passaging, the cells will also cease to proliferate and have the tendency to convert into an elongated, mesenchymal cell phenotype. If few colonies appear from days 7 to 14, or if the colonies are small in size, troubleshooting can include increasing cell density by passaging P0 colonies into a T-25 flask instead of a T-75.
Once the technique is mastered, the resultant BOECs can be used in several applications, including in vitro studies of endothelial cell biology, disease modeling and drug screening, as well as in vivo cell transplantation therapies. An important consideration for the development of any cell therapy process is to use cells that are free from pathogenic mutations. We have previously shown that BOECs isolated using our protocol possess genomes that are free from copy number variations and are thus representative of the individual from which they were collected. In addition, we have also demonstrated that the majority of BOEC-derived iPSC lines are free from copy number variations.13 This contrasts with previous reports of copy number variation in fibroblast-derived iPSCs. To date, these cells remain the only iPSCs for which this degree of genomic fidelity has been reported. This feature is important for the field of iPSC biology and the use of iPSCs in disease modeling, drug screening and future cell transplantation therapies.
The authors have nothing to disclose.
This work was supported by grants funded by the British Heart Foundation (BHF), Dinosaur Trust, McAlpine Foundation, Fondation Leducq, Fight for Sight, the Cambridge Biomedical Research Centre, National Institute of Health Research including (i) the BHF Oxbridge Centre of Regenerative Medicine [RM/13/3/30159], (ii) the BHF Cambridge Centre of Research Excellence, (iii) Addenbrooke’s Hospital, Cambridge University Hospitals NHS Foundation Trust and (iv) Papworth Hospital NHS Foundation Trust, and supported the Cambridge NIHR BRC Cell Phenotyping Hub. MLO is funded by a BHF Intermediate Fellowship. FNK is funded by a BHF PhD Studentship.
For blood collection | |||
60 mL syringe with luer-lok tip | BD | 309653 | |
19G Surflo Winged Infusion Set | Terumo | SV-19BL | |
50 mL conical centrifuge tube | StarLab | E1450 | 2 per donor |
Sodium Citrate | Martindale Pharmaceuticals | 270541 | |
Name | Company | Catalog Number | Comments |
For buffy coat isolation | |||
Ficoll-Paque Plus | GE Healthcare | 17-1440-03 | |
Dulbecco’s PBS (without Ca2+ and Mg2+) | Sigma-Aldrich | D8537 | |
Sterile wrapped plastic transfer pipettes | Appleton Woods | KC231 | |
Turk’s Solution | Millipore | 1.093E+09 | |
Name | Company | Catalog Number | Comments |
For cell culture, passaging and freezing cells | |||
Type 1 Collagen (derived from rat tail) | BD Biosciences | 35-4236 | |
Dulbecco’s PBS (without Ca2+ and Mg2+) | Sigma-Aldrich | D8537 | |
0.02M Acetic Acid | Sigma-Aldrich | A6283 | prepared in reagent grade water |
Endothelial Growth Medium-2MV (containing Bullet Kit, but not serum) |
Lonza | CC-3202 | Note: It is essential that the medium does not contain heparin. Do not use EGM-2. |
Fetal Bovine Serum (U.S.), Defined | Hyclone | SH30070 | |
10x Trypsin EDTA | Gibco | T4174 | Dilute to 1x in PBS prior to use |
Heat Inactivated FBS | Gibco | 10500-064 | |
DMEM | Gibco | 41965-039 | |
DMSO | Sigma-Aldrich | 276855 | |
Nalgene Mr. Frosty Freezing Container | Sigma-Aldrich | C1562 | |
Name | Company | Catalog Number | Comments |
For flow cytometric characterization | |||
FITC-conjugated mouse anti-human CD14 | BD Biosciences | 555397 | Mouse IgG1k, Clone: WM59 Dilution: 1:20 |
FITC-conjugated mouse anti-human CD31 | BD Biosciences | 555445 | Mouse IgG1k, Clone: WM59 Dilution: 1:20 |
APC-conjugated mouse anti-human CD34 | BD Biosciences | 555824 | Mouse IgG1k, Clone: 581/CD34 Dilution: 1:20 |
FITC-conjugated mouse anti-human CD45 | BD Biosciences | 560976 | Mouse IgG1k, Clone: HI30 Dilution: 1:20 |
APC-conjugated mouse anti-human VEGFR2 | R&D Systems | FAB357A | Mouse IgG1, Clone: 89106 Dilution: 1:10 |
FITC-conjugated mouse IgG1k isotype control | BD Biosciences | 555748 | Clone: MOPC-21 Dilution: 1:20 |
APC-conjugated mouse IgG1k isotype control | BD Biosciences | 555751 | Clone: MOPC-21 Dilution: 1:20 |
APC-conjugated mouse IgG1k isotype control | R&D Systems | IC002A Dilution: 1:10 |
Clone: 11711 |
EDTA, 0.5M solution | Sigma-Aldrich | E7889 | |
Name | Company | Catalog Number | Comments |
For immunofluorescent microscopy | |||
Corning Costar 24-well tissue culture plate | Sigma-Aldrich | CLS3527 | |
Paraformaldehyde | Sigma-Aldrich | 158127 | |
BSA | Sigma-Aldrich | A7906 | |
Polysorbate 20 | Sigma-Aldrich | P2287 | |
Monoclonal mouse anti-human CD34 antibody | R&D Systems | MAB72271 | Clone 756510, IgG1, use at 10 μg/ml |
Polyclonal goat anti-human VE-cadherin (CD144) | R&D Systems | AF938 | Antigen affinity- purified IgG, use at 1:300 |
Monoclonal rabbit anti-human Von Willebrand Factor (vWF) | Abcam | ab154193 | Clone EPSISR15, use at 1:250 |
Donkey anti-mouse IgG (H+L) secondary antibody, Alexa Fluor 488 conjugate | Life Technologies | A-21202 | Polyclonal, 2 mg/ml, use at 1:200 |
Donkey anti-goat IgG (H+L) secondary antibody, Alexa Fluor 488 conjugate | Life Technologies | A-11055 | Polyclonal, 2 mg/ml, 1:200 |
Donkey anti-rabbit IgG (H+L) secondary antibody, Alexa Fluor 568 conjugate | Life Technologies | A-10042 | Polyclonal, 2 mg/ml, 1:200 |
DAPI (4′,6-Diamidino-2-phenylindole dihydrochloride) | Sigma-Aldrich | D9542 | use at 1 μg/ml |