Generation of Mouse Induced Pluripotent Stem Cells Without Viral Vectors

TLDR

Induced pluripotent stem cells have been produced from mouse and human somatic cells using viral vectors, but viral integration raises tumorigenicity risks, limiting their therapeutic potential. This study demonstrates the generation of mouse iPS cells without viral vectors. Transfecting mouse embryonic fibroblasts with two plasmids encoding Oct3/4, Sox2, Klf4, and c‑Myc yielded virus‑free iPS cells that formed teratomas and contributed to chimeras, thereby mitigating safety concerns for regenerative medicine.

Abstract

Induced pluripotent stem (iPS) cells have been generated from mouse and human somatic cells by introducing Oct3/4 and Sox2 with either Klf4 and c-Myc or Nanog and Lin28 using retroviruses or lentiviruses. Patient-specific iPS cells could be useful in drug discovery and regenerative medicine. However, viral integration into the host genome increases the risk of tumorigenicity. Here, we report the generation of mouse iPS cells without viral vectors. Repeated transfection of two expression plasmids, one containing the complementary DNAs (cDNAs) of Oct3/4, Sox2, and Klf4 and the other containing the c-Myc cDNA, into mouse embryonic fibroblasts resulted in iPS cells without evidence of plasmid integration, which produced teratomas when transplanted into mice and contributed to adult chimeras. The production of virus-free iPS cells, albeit from embryonic fibroblasts, addresses a critical safety concern for potential use of iPS cells in regenerative medicine.