Stem Cell Biology Department, National Institute for Research in Reproductive Health (Indian Council of Medical Research), Jehangir Merwanji Street, Parel, Mumbai, 400 012, India.
Stem Cell Rev Rep. 2017 Apr;13(2):202-216. doi: 10.1007/s12015-016-9714-0.
Very small embryonic-like stem cells (VSELs) have been reported in various adult tissues, express pluripotent and primordial germ cells (PGCs) specific markers, are mobilized under stress/disease conditions, give rise to tissue committed progenitors and thus help regenerate and maintain homeostasis. The aim of the present study was to evaluate in vitro differentiation potential of VSELs using a quantitative approach. VSELs were collected from mouse bone marrow after 4 days of 5-fluorouracil (5-FU, 150 mg/Kg) treatment, further enriched by size based filtration and cultured on a feeder support in the presence of specific differentiation media. Cultured VSELs were found to differentiate into all three embryonic germ cell lineages, germ and hematopoietic cells after 14 days in culture. This was confirmed by studying Nestin, PDX-1, NKX2.5, DAZL, CD45 and other markers expression by various approaches. Very small, CD45 negative cells collected and enriched from GFP positive 5-FU treated mice bone marrow transitioned into CD45 positive cells in vitro thus demonstrating that VSELs can give rise to hematopoietic stem cells (HSCs). We envision that VSELs may be responsible for plasticity and ability of bone marrow cells to give rise to non-hematopoietic tissue progenitors of all 3 germ layers. Moreover the ability of VSELs to differentiate into germ cells as well as all the three lineages provides further evidence to support their pluripotent state and confirms developmental link between bone marrow VSELs and PGCs. The property of quiescence, no risk of teratoma formation and autologus source, make pluripotent VSELs a potential candidate to facilitate endogenous regeneration compared to cell replacement strategy envisioned using embryonic and induced pluripotent stem cells.
非常小的胚胎样干细胞（VSELs）已在各种成人组织中被报道，表达多能性和原始生殖细胞（PGCs）特异性标志物，在应激/疾病条件下被动员，产生组织定向祖细胞，从而有助于再生和维持体内平衡。本研究的目的是使用定量方法评估 VSELs 的体外分化潜能。VSELs 是从小鼠骨髓中在 5-氟尿嘧啶（5-FU，150mg/Kg）处理 4 天后收集的，进一步通过基于大小的过滤进行富集，并在饲养细胞支持物上培养，同时使用特定的分化培养基。培养的 VSELs 在培养 14 天后被发现分化为所有三种胚胎生殖细胞谱系、生殖细胞和造血细胞。这通过研究巢蛋白、PDX-1、NKX2.5、DAZL、CD45 和其他标志物的表达得到了证实。从小鼠骨髓中收集和富集的 GFP 阳性 5-FU 处理的非常小的 CD45 阴性细胞在体外转化为 CD45 阳性细胞，这表明 VSELs 可以产生造血干细胞（HSCs）。我们设想 VSELs 可能负责骨髓细胞的可塑性和产生所有 3 个胚层的非造血组织祖细胞的能力。此外，VSELs 分化为生殖细胞以及所有三个谱系的能力提供了进一步的证据，支持它们的多能状态，并证实了骨髓 VSELs 和 PGCs 之间的发育联系。静止、无畸胎瘤形成风险和自体来源的特性，使多能 VSELs 成为促进内源性再生的潜在候选物，与使用胚胎和诱导多能干细胞设想的细胞替代策略相比。
