The Department of Pediatrics/Human Development, Center For Integrative Toxicology, College of Human Medicine, Michigan State University, East Lansing, MI, USA.
Adv Exp Med Biol. 2018;1103:131-152. doi: 10.1007/978-4-431-56847-6_7.
From the transition of single-cell organisms to multicellularity of metazoans, evolutionary pressures selected new genes and phenotypes to cope with the oxygenation of the Earth's environment, especially via the symbiotic acquisition of the mitochondrial organelle. There were many new genes and phenotypes that appeared, namely, stem cells, low-oxygen-micro-environments to house these genes ("niches"), new epigenetic mechanisms to regulate , selectively, the gene repertoire to control proliferation, differentiation, apoptosis, senescence and DNA protection mechanisms, including antioxidant genes and DNA repair. This transition required a critical regulation of the metabolism of glucose to produce energy for both the stem cell quiescent state and the energy-requiring differentiated state. While the totipotent-, embryonic-, pluripotent-, and a few adult organ-specific stem cells were recognized, only relatively recently, because of the isolation of somatic cell nuclear transfer (SCNT) stem cells and "induced pluripotent stem" cells, challenges to the origin of these "iPS" cells have been made. The isolation and characterization of human MUSE stem cells and more adult organ-specific adult stem cells have indicated that these MUSE cells have many shared characteristics of the "iPS" cells, yet they do not form teratomas but can give rise to the trigeminal cell layers. While the MUSE cells are a subset of human fibroblastic cells, they have not been characterized, yet, for the mitochondrial metabolic genes, either in the stem cell state or during their differentiation processes. A description of other human adult stem cells will be made to set future studies of how the MUSE stem cells compare to all other stem cells.
从单细胞生物向多细胞后生动物的转变过程中，进化压力选择了新的基因和表型来应对地球环境的氧化，特别是通过共生获得线粒体细胞器。出现了许多新的基因和表型，即干细胞、为这些基因提供住所的低氧微环境（“龛位”）、新的表观遗传机制，选择性地调节基因库，以控制增殖、分化、凋亡、衰老和 DNA 保护机制，包括抗氧化基因和 DNA 修复。这种转变需要对葡萄糖代谢进行严格调控，以产生能量，满足干细胞静止状态和能量需求的分化状态。虽然全能性、胚胎性、多能性和少数成人器官特异性干细胞已经得到认可，但直到最近，由于体细胞细胞核移植（SCNT）干细胞和“诱导多能性干细胞”的分离，这些“iPS”细胞的起源才受到挑战。人类 MUSE 干细胞和更多成人器官特异性成体干细胞的分离和鉴定表明，这些 MUSE 细胞具有许多“iPS”细胞的共同特征，但它们不会形成畸胎瘤，而是可以产生三叉神经细胞层。虽然 MUSE 细胞是人类成纤维细胞的一个子集，但它们的线粒体代谢基因在干细胞状态或分化过程中尚未得到表征。本文将对其他人类成体干细胞进行描述，以设定未来的研究，比较 MUSE 干细胞与所有其他干细胞的差异。
