Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
Stem Cells. 2010 Aug;28(8):1315-25. doi: 10.1002/stem.456.
The low efficiency of reprogramming and genomic integration of virus vectors obscure the potential application of induced pluripotent stem (iPS) cells; therefore, identification of chemicals and cooperative factors that may improve the generation of iPS cells will be of great value. Moreover, the cellular mechanisms that limit the reprogramming efficiency need to be investigated. Through screening a chemical library, we found that two chemicals reported to upregulate E-cadherin considerably increase the reprogramming efficiency. Further study of the process indicated that E-cadherin is upregulated during reprogramming and the established iPS cells possess E-cadherin-mediated cell-cell contact, morphologically indistinguishable from embryonic stem (ES) cells. Our experiments also demonstrate that overexpression of E-cadherin significantly enhances reprogramming efficiency, whereas knockdown of endogenous E-cadherin reduces the efficiency. Consistently, abrogation of cell-cell contact by the inhibitory peptide or the neutralizing antibody against the extracellular domain of E-cadherin compromises iPS cell generation. Further mechanistic study reveals that adhesive binding activity of E-cadherin is required. Our results highlight the critical role of E-cadherin-mediated cell-cell contact in reprogramming and suggest new routes for more efficient iPS cell generation.
病毒载体的重编程和基因组整合效率低下，这使得诱导多能干细胞（iPS）的潜在应用受到了阻碍；因此，鉴定可能提高 iPS 细胞生成效率的化学物质和协同因子将具有重要价值。此外，还需要研究限制重编程效率的细胞机制。通过筛选化学文库，我们发现两种被报道能显著上调 E-钙黏蛋白的化学物质可极大地提高重编程效率。进一步的研究表明，E-钙黏蛋白在重编程过程中上调，并且所建立的 iPS 细胞具有 E-钙黏蛋白介导的细胞间接触，在形态上与胚胎干细胞（ES）细胞无法区分。我们的实验还表明，E-钙黏蛋白的过表达可显著提高重编程效率，而内源性 E-钙黏蛋白的敲低则降低了效率。同样，E-钙黏蛋白的细胞间接触通过抑制肽或针对 E-钙黏蛋白细胞外结构域的中和抗体的抑制，会损害 iPS 细胞的生成。进一步的机制研究表明，E-钙黏蛋白的黏附结合活性是必需的。我们的研究结果强调了 E-钙黏蛋白介导的细胞间接触在重编程中的关键作用，并为更高效的 iPS 细胞生成提供了新途径。
