Molecular mechanisms underlying replicative stress and genome damage in pluripotent stem cells

早期胚胎中的多能干细胞（PSCs）会产生体内所有的体细胞。维持PSCs的遗传完整性对于防止遗传缺陷传递给多个子代细胞至关重要，这将对发育中的胚胎有害。当置于适当的培养条件下时，PSCs保留了从所有三个胚胎胚层产生分化细胞的能力，同时获得了广泛的自我更新能力，从而为研究控制基因组完整性的机制提供了一个优秀的遗传正常模型系统。我们和其他人之前已经表明，psc在长期培养中获得非随机遗传变化。然而，其获得的分子机制仍然知之甚少。为此，我们的项目将确定不同的基因组损伤机制对我们观察到的共同遗传变化的贡献。我们还将阐明外部环境（特别是培养基成分）如何增强或减少这些损伤机制。我们之前的数据表明，在不同的培养基和环境条件下生长的细胞显著改变了它们的突变率。其他研究小组的工作强调白蛋白是培养基的关键组成部分，对于稳定小分子和离子以及清除可能对大分子（尤其是DNA）有害的自由基是必要的。因此，我们将与专业生产重组白蛋白的工业伙伴Albumedix合作，确定PSCs基因组损伤的内在机制和生态位条件的贡献。

Pluripotent stem cells (PSCs) in the early embryo give rise to all ofthe somatic cells in the body. Maintenance of the genetic integrity of PSCs isessential for preventing genetic defects to be passed onto multiple progeny cells,which would be detrimental for a developing embryo. When placed underappropriate culture conditions, PSCs retain the ability to give rise to differentiatedcells from all three embryonic germ layers, whilst acquiring the ability to self-renew extensively and thus provide an excellent, genetically normal modelsystem to investigate mechanisms that control genome integrity. We and othershave previously shown that PSCs acquire non-random genetic changes uponprolonged culture. However, the molecular mechanisms underlying theiracquisition remain poorly understood. To this end, our project will determine thecontribution of different genome damage mechanisms to the common geneticchanges we observe. We will also elucidate how extrinsic environment(specifically, culture medium composition) enhance or diminish these damagemechanisms. Our previous data has shown that growing cells in different culturemedia and environmental conditions significantly alters their mutation rates.Work from other groups highlighted albumin as a key component of the medium,necessary for stabilizing small molecules and ions and scavenging free radicalsthat could be harmful for macromolecules, particularly the DNA. Hence, incollaboration with our industrial partner Albumedix, who specializes inrecombinant albumin production, we will determine the contribution of intrinsicmechanisms and niche conditions on genome damage of PSCs.