Transient non-integrative nuclear reprogramming promotes multifaceted reversal of aging in human cells

Transient reprogramming, mediated by transient expression of mRNAs, promotes a rapid reversal of both cellular aging and of epigenetic clock in human fibroblasts and endothelial cells. Transient on-integrative reprogramming protocol optimized based on a cocktail of mRNAs expressing OCT4, SOX2, KLF4, c-MYC, LIN28 and NANOG (OSKMLN). This protocol consistently produces induced pluripotent stem cell (iPSC) colonies, regardless of age of the donors, after 12-15 daily transfections. Here we adopted a transient reprogramming protocol where OSKMLN were daily transfected for only four consecutive days. Methylation profiles were used to estimate two epigenetic clocks: the pan tissue clock from Horvath 2013 (PubMedIdentifier PMID: 24138928 or PMCID: PMC4015143) and the skin & blood clock from Horvath 2018 (PMID: 30048243 PMCID: PMC6075434). Here we adopted a transient reprogramming protocol where OSKMLN were daily transfected for only four consecutive days. Genome wide DNA methylation profiling of two cell types: human fibroblasts from skin and endothelial cells from veins. The Illumina Infinium EPIC DNA methylation Beadchip was used to obtain DNA methylation profiles