The present invention relates to a novel method for preparing induced pluripotent stem cells (iPSCs) by introducing three genes, Oct3/4, Sox2, and Parp1, into somatic cells. The present invention also relates to the iPSCs produced by the aforementioned method. Also provided is a method of rejuvenating cells by use of a PARylated protein or an enzyme with PARylation activity. Further provided is a method for inducing the secretion of interferon-&gamma； inducible protein-10 (IP-10) comprising administering to a subject in need thereof an effective amount of iPSCs or iPSC-CM.
