Commonly used mesenchymal stem cell markers and tracking labels: Limitations and challenges.
Commonly used mesenchymal stem cell markers and tracking labels: Limitations and challenges.
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DOI：
10.14670/hh-28.1109
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发表时间：
2013-09
影响因子：
2
通讯作者：
Lue TF
中科院分区：
文献类型：
--
作者：
Lin CS;Xin ZC;Dai J;Lue TF
早期的观察表明，培养的间充质干细胞（MSC）可以被诱导表现出骨细胞和软骨细胞的某些特征，这导致了他们可以通过细胞分化移植用于组织修复的建议。因此，许多随后的临床前研究与移植的MSC已努力证明，细胞分化的治疗效果的潜在机制。这些研究通常遵循国际细胞治疗学会设定的最低标准，通过使用CD 70、CD 90和CD 105作为阳性标志物，CD 34作为阴性标志物来确保MSC身份。然而，这三种阳性标志物在多种细胞中共表达，因此，即使组合使用，它们也肯定不能在体内识别MSC。另一种常用的MSC标记物Stro-1已被证明是一种内皮抗原，它是否可以在体内识别MSC仍然未知。另一方面，提出的阴性标志物CD 34已越来越多地显示在天然MSC中表达，例如在脂肪组织中。它还有助于确定MSC可能是驻留在毛细血管和较大血管外膜中的血管干细胞（VSCs）。这些细胞不表达CD 31、CD 104 b或α-SMA，因此命名为CD 34 + CD 31-CD 140 b-SMA-。许多临床前MSC移植研究也试图通过使用标记的MSC来证明细胞分化。然而，所有常用的标签都有缺点，往往使数据解释复杂化。β-gal（LacZ）基因作为标记是有问题的，因为许多哺乳动物组织具有内源性β-gal活性。GFP基因也有类似的问题，因为许多哺乳动物组织都是内源性荧光的。细胞膜标记物DiI可被宿主细胞吸附，核染色剂Hoechst染料和DAPI可转移到宿主细胞。胸苷类似物BrdU与由于苛刻的组织学条件导致的细胞蛋白抗原性丧失相关。较新的胸苷类似物EdU更容易通过与叠氮化物缀合的Alexa荧光剂的化学反应检测到，但某些骨髓细胞在没有EdU的情况下对这些荧光剂有反应。在设计或解释MSC移植实验时需要考虑这些警告。
Early observations that cultured mesenchymal stem cells (MSCs) could be induced to exhibit certain characteristics of osteocytes and chondrocytes led to the proposal that they could be transplanted for tissue repair through cellular differentiation. Therefore, many subsequent preclinical studies with transplanted MSCs have strived to demonstrate that cellular differentiation was the underlying mechanism for the therapeutic effect. These studies generally followed the minimal criteria set by The International Society for Cellular Therapy in assuring MSC identity by using CD70, CD90, and CD105 as positive markers and CD34 as a negative marker. However, the three positive markers are co-expressed in a wide variety of cells, and therefore, even when used in combination, they are certainly incapable of identifying MSCs in vivo. Another frequently used MSC marker, Stro-1, has been shown to be an endothelial antigen and whether it can identify MSCs in vivo remains unknown. On the other hand, the proposed negative marker CD34 has increasingly been shown to be expressed in native MSCs, such as in the adipose tissue. It has also helped establish that MSCs are likely vascular stem cells (VSCs) that reside in the capillaries and in the adventitia of larger blood vessels. These cells do not express CD31, CD104b, or α-SMA, and therefore are designated as CD34+CD31-CD140b-SMA-. Many preclinical MSC transplantation studies have also attempted to demonstrate cellular differentiation by using labeled MSCs. However, all commonly used labels have shortcomings that often complicate data interpretation. The β-gal (LacZ) gene as a label is problematic because many mammalian tissues have endogenous β-gal activities. The GFP gene is similarly problematic because many mammalian tissues are endogenously fluorescent. The cell membrane label DiI can be adsorbed by host cells, and nuclear stains Hoechst dyes and DAPI can be transferred to host cells. Thymidine analog BrdU is associated with loss of cellular protein antigenicity due to harsh histological conditions. Newer thymidine analog EdU is easier to detect by chemical reaction to azide-conjugated Alexa fluors, but certain bone marrow cells are reactive to these fluors in the absence of EdU. These caveats need to be taken into consideration when designing or interpreting MSC transplantation experiments.