Winter Randolph L, Seeto Wen J, Tian Yuan, Caldwell Fred J, Lipke Elizabeth A, Wooldridge Anne A
Department of Clinical Sciences, Auburn University, College of Veterinary Medicine, Auburn, AL, USA.
Department of Chemical Engineering, Auburn University, Auburn, AL, USA.
BMC Vet Res. 2018 Aug 23;14(1):247. doi: 10.1186/s12917-018-1572-3.
Endothelial progenitor cells (EPCs) contribute to neovascularization and vascular repair in vivo and are attractive for clinical use in ischemic disease. Tracking of stem and progenitor cells is essential to determine engraftment after administration. Semiconductor quantum dots (QD) are promising for cell labeling due to their ease of uptake by many cell lines and their continued presence after many cell generations. The purpose of this study was to evaluate function and growth of equine EPCs after QD labeling. Additionally, this study evaluated the duration of QD label retention and mechanisms of QD label loss.
Endothelial colony forming cells (ECFCs) from adult horses (N = 3) were employed for this study, with QD labeled and unlabeled ECFCs tested from each horse. Cell proliferation of ECFCs labeled with QD at 20 nM was quantified by comparing the number of cell doublings per day (NCD) and the population doubling time (PDT) in labeled and unlabeled cells. Function of labeled and unlabeled ECFCs was assessed by comparing uptake of acetylated low-density lipoprotein (DiO-Ac-LDL) and tubule formation on growth factor containing matrix. Cell proliferation was not impacted by QD labeling; both NCD (p = 0. 95) and PDT (P = 0. 91) did not differ between unlabeled and QD labeled cells. Function of ECFCs assessed by DiO-Ac-LDL and tubule formation was also not different between unlabeled and QD labeled cells (P = 0. 33 and P = 0. 52, respectively). ECFCs retained their QD labeling over 7 passages with both 5 nM and 20 nM label concentrations. Reduction in label intensity was observed over time, and the mechanism was determined to be cell division.
Equine ECFCs are effectively labeled with QD, and QD concentrations up to 20 nM do not affect cell growth or function. QD label loss is a result of cell division. The use of QD labeling with equine EPCs may be an ideal way to track engraftment of EPCs for in vivo applications.
内皮祖细胞（EPCs）有助于体内新血管形成和血管修复，在缺血性疾病的临床应用中具有吸引力。追踪干细胞和祖细胞对于确定给药后的植入情况至关重要。半导体量子点（QD）因其易于被许多细胞系摄取且在多个细胞代后仍持续存在，在细胞标记方面很有前景。本研究的目的是评估量子点标记后马EPCs的功能和生长情况。此外，本研究还评估了量子点标记保留的持续时间以及量子点标记丢失的机制。
本研究使用了成年马（N = 3）的内皮集落形成细胞（ECFCs），对每匹马的量子点标记和未标记的ECFCs进行了测试。通过比较标记和未标记细胞每天的细胞倍增数（NCD）和群体倍增时间（PDT），对用20 nM量子点标记的ECFCs的细胞增殖进行了定量。通过比较乙酰化低密度脂蛋白（DiO-Ac-LDL）的摄取和在含生长因子基质上的小管形成，评估了标记和未标记ECFCs的功能。细胞增殖不受量子点标记的影响；未标记和量子点标记细胞之间的NCD（p = 0.95）和PDT（P = 0.91）均无差异。通过DiO-Ac-LDL和小管形成评估的ECFCs功能在未标记和量子点标记细胞之间也没有差异（分别为P = 0.33和P = 0.52）。在5 nM和20 nM标记浓度下，ECFCs在7代以上都保留了它们的量子点标记。随着时间的推移，观察到标记强度降低，其机制被确定为细胞分裂。
马ECFCs被量子点有效标记,高达20 nM的量子点浓度不影响细胞生长或功能。量子点标记丢失是细胞分裂的结果。将量子点标记用于马EPCs可能是追踪EPCs体内植入情况的理想方法。
