Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0322, USA ; Department of Bioengineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0322, USA.
College of Life Sciences, Peking University, Beijing 100871, China.
Stem Cell Reports. 2014 Mar 27;2(4):399-405. doi: 10.1016/j.stemcr.2014.02.005. eCollection 2014 Apr 8.
Ectopic expression of reprogramming factors has been widely adopted to reprogram somatic nucleus into a pluripotent state (induced pluripotent stem cells [iPSCs]). However, genetic aberrations such as somatic gene mutation in the resulting iPSCs have raised concerns regarding their clinical utility. To test whether the increased somatic mutations are primarily the by-products of current reprogramming methods, we reprogrammed embryonic fibroblasts of inbred C57BL/6 mice into either iPSCs (8 lines, 4 previously published) or embryonic stem cells (ESCs) with somatic cell nuclear transfer (SCNT ESCs; 11 lines). Exome sequencing of these lines indicates a significantly lower mutation load in SCNT ESCs than iPSCs of syngeneic background. In addition, one SCNT-ESC line has no detectable exome mutation, and two pairs of SCNT-ESC lines only have shared preexisting mutations. In contrast, every iPSC line carries unique mutations. Our study highlights the need for improving reprogramming methods in more physiologically relevant conditions.
重编程因子的异位表达已被广泛用于将体细胞核重编程为多能状态（诱导多能干细胞[iPSCs]）。然而，由此产生的 iPSCs 中的体细胞基因突变等遗传异常引起了人们对其临床应用的关注。为了测试增加的体细胞突变是否主要是当前重编程方法的副产品，我们将近交 C57BL/6 小鼠的胚胎成纤维细胞重编程为 iPSCs（8 个系，其中 4 个之前已发表）或体细胞核移植（SCNT-ESCs；11 个系）的胚胎干细胞。对这些系进行外显子组测序表明，SCNT-ESC 中的突变负荷明显低于同基因背景的 iPSC。此外，一个 SCNT-ESC 系没有检测到外显子突变，两对 SCNT-ESC 系只有共同存在的预先存在的突变。相比之下，每个 iPSC 系都携带独特的突变。我们的研究强调了需要在更生理相关的条件下改进重编程方法。
