Department of Medicine, Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA.
Department of Obstetrics and Gynecology, West China Second University Hospital, Sichuan University, Chengdu, China.
Stem Cell Res Ther. 2020 Feb 13;11(1):55. doi: 10.1186/s13287-020-1567-4.
In a number of disease processes, the body is unable to repair injured tissue, promoting the need to develop strategies for tissue repair and regeneration, including the use of cellular therapeutics. Trophoblast stem cells (TSCs) are considered putative stem cells as they differentiate into other subtypes of trophoblast cells. To identify cells for future therapeutic strategies, we investigated whether TSCs have properties of stem/progenitor cells including self-renewal and the capacity to differentiate into parenchymal cells of fetal organs, in vitro and in vivo.
TSCs were isolated using anti-CD117 micro-beads, from embryonic day 18.5 placentas. In vitro, CD117 TSCs were cultured, at a limiting dilution in growth medium for the development of multicellular clones and in specialized medium for differentiation into lung epithelial cells, cardiomyocytes, and retinal photoreceptor cells. CD117 TSCs were also injected in utero into lung, heart, and the sub-retinal space of embryonic day 13.5 fetuses, and the organs were harvested for histological assessment after a natural delivery.
We first identified CD117 cells within the labyrinth zone and chorionic basal plate of murine placentas in late pregnancy, embryonic day 18.5. CD117 TSCs formed multicellular clones that remained positive for CD117 in vitro, consistent with self-renewal properties. The clonal cells demonstrated multipotency, capable of differentiating into lung epithelial cells (endoderm), cardiomyocytes (mesoderm), and retinal photoreceptor cells (ectoderm). Finally, injection of CD117 TSCs in utero into lungs, hearts, and the sub-retinal spaces of fetuses resulted in their engraftment on day 1 after birth, and the CD117 TSCs differentiated into lung alveolar epithelial cells, heart cardiomyocytes, and retina photoreceptor cells, corresponding with the organs in which they were injected.
Our findings demonstrate that CD117 TSCs have the properties of stem cells including clonogenicity, self-renewal, and multipotency. In utero administration of CD117 TSCs engraft and differentiate into resident cells of the lung, heart, and retina during mouse development.
在许多疾病过程中，身体无法修复受损组织，因此需要开发组织修复和再生策略，包括使用细胞治疗。滋养层干细胞（TSC）被认为是多能干细胞，因为它们可以分化为其他滋养层细胞亚型。为了确定未来治疗策略的细胞，我们研究了 TSC 是否具有干细胞/祖细胞的特性，包括自我更新和分化为胎儿器官实质细胞的能力，无论是在体外还是体内。
我们使用抗 CD117 微珠从胚胎第 18.5 天的胎盘分离 TSC。在体外，将 CD117 TSC 进行培养，在生长培养基中进行有限稀释以开发多细胞克隆，并在专门的培养基中分化为肺上皮细胞、心肌细胞和视网膜光感受器细胞。我们还将 CD117 TSC 注射到胚胎第 13.5 天胎儿的肺、心脏和视网膜下腔，在自然分娩后收获器官进行组织学评估。
我们首先在妊娠晚期即胚胎第 18.5 天的胎盘母体迷路区和绒毛基底层鉴定出 CD117 细胞。CD117 TSC 形成多细胞克隆，在体外保持 CD117 阳性，这与自我更新特性一致。克隆细胞表现出多能性，能够分化为肺上皮细胞（内胚层）、心肌细胞（中胚层）和视网膜光感受器细胞（外胚层）。最后，将 CD117 TSC 注射到胎儿的肺、心脏和视网膜下腔，在出生后第 1 天即可植入，CD117 TSC 分化为肺泡上皮细胞、心肌细胞和视网膜光感受器细胞，与注射的器官相对应。
我们的发现表明，CD117 TSC 具有干细胞的特性，包括克隆形成能力、自我更新和多能性。在体内给予 CD117 TSC 后，在小鼠发育过程中，它们可以植入并分化为肺、心脏和视网膜的固有细胞。
