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.
最近までは、新しい血管の出生後の発生は、既存の血管の内皮細胞からの新しい血管の出芽のように定義される、血管新生と呼ばれるプロセスを介して排他的に起こると考えられていた。1このプロセスは、脈管形成の対比、または胚発生の間に排他的に起こると考えられていた血管内皮前駆細胞からの血管のデノボ形成2が、より最近の研究では、同定され、成人の末梢血中の内皮前駆細胞(EPC)を循環する単離しました。これらの細胞は、培養中で成熟内皮細胞に分化する能力を有し、出生後の血管に関与すると考えられている。3,4
これらのEPCの単離および拡張のためのプロトコールは、典型的にはvascul含む内皮増殖因子を含む培地で、末梢血単核細胞(PBMNCs)の培地を含みますAR内皮増殖因子(VEGF)および線維芽細胞増殖因子-2 5-8 EPC培養は劇的に異なる細胞型の多様性を生み出します。初期の文化(<7日)は、「初期」のEPCとして文献で知られている単球細胞の種類によって支配されています。その名前にもかかわらず、これらの細胞は、単球マーカーCD14を発現し、前駆細胞マーカーCD34について陰性であると古典内皮マーカーCD31およびVEGF受容体2(VEGFR2)の最小限のレベルで発現する。5継続文化は、細胞の二次集団に生じます後半伸長のEPCまたは内皮様細胞のように控えめなコロニーを出現する血液伸長内皮細胞(BOECs)、として知られています。単球の早期のEPCとは異なり、また、内皮コロニー形成細胞(ECFCs)、伸長内皮細胞または後期成長内皮細胞と呼ばれているBOECsは、内皮細胞単層の典型的なものである敷石状の形態を示し、表面マーカーに非常に似ています5遺伝子発現9は、内皮細胞に成熟します。
末梢血からの内皮様細胞の生成は、特に、肺動脈性肺高血圧症(PAH)10またはフォンヴィレブランド病などの血管障害に関連した内皮細胞の機能不全の研究のために、いくつかの利点を提供しています。11前BOECsの可用性に、内皮細胞は死だけや臓器移植の際に外植臓器由来、または出生時の臍帯静脈から単離することができました。この減少可用性は、内皮、心臓血管疾患の患者由来の細胞、ならびに内皮細胞および血液細胞または壁細胞のいずれかの間の相互作用の生物学の理解に重大な制限を表します。また、これらのソースからの内皮細胞の純粋な集団を単離し、培養して技術的に困難であり、これらの方法によって誘導された細胞のみが限られを示しますD増殖能力。 BOECsは、したがって、患者由来の初代内皮細胞の単離および培養のための貴重な代理を提供しています。
それらのインビトロ用途に加えて、BOECsは、自家細胞移植療法においても有用である可能性があります。これらのアプリケーションは、内皮細胞の血管新生を促進するための移植(12およびその中の参考文献を参照のこと)、ならびに人工多能性幹細胞(iPS細胞)の発生の両方を含む。13 BOEC由来のiPS細胞は、疾患のモデリングのために使用され、出発物質として巨大な可能性を提供することができ自家細胞治療用材料。 BOECsは、より速く、皮膚線維芽細胞よりも高い効率で再プログラム。さらに、BOECsも翻訳アプリケーションに適して任意の技術の本質的な特徴である、核型異常のないiPS細胞の生成を可能にします。患者の血液サンプルAからiPS細胞を生成する能力LSOは、それによって創傷治癒障害を有する患者からの細胞の発生を促進する、皮膚生検および皮膚線維芽細胞の生成のための必要性を排除する、または非常に若いです。
以下に詳述するプロトコル、によって承認され、国家研究倫理サービス委員会(東イングランド)のガイドラインに沿って行われ、比較的小容量から90%以上の効率でBOECsの生成のための、シンプルで信頼性の高い方法を提供する(60 ml)の末梢血。これらの細胞は、高度に増殖性であり、単一の血液サンプルからの細胞の数百万の生成を可能にする、繰り返し継代することができます。
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 |