Methylation Pattern of Human Mesenchymal Stromal Cells

In this study, we have analyzed DNA methylation changes upon long-term culture and aging of MSC by using the HumanMethylation27 BeadChip assessing 27,578 unique CpG sites. Cells were taken from bone marrow aspirates from iliac crest (BM) of healthy donors or from the caput femoris (HIP) of elderly patients that received femoral head prosthesis.Overall, the methylation pattern was maintained throughout both long-term culture and aging but highly significant differences were observed at specific CpG sites. Notably, methylation changes in MSC were related in long-term culture and aging in vivo. Mesenchymal stromal cells (MSC) were isolated from human bone marrow as described before (Wagner et al., 2006, Exp Hematol, 34, 536-548; Wagner et al.,2008, PLoS One 21;3(5):e2213.; Wagner et al., PLoS One. 2009 Jun 9;4(6):e5846.) Cells were always replated when grown to confluency. A sample for DNA isolation was taken at every passage until the cells finally became senescent. For methylation profiles upon long-term culture we used the samples of early passage (P2) and senescent passage (PX). For methylation profiles upon aging we have only used the samples of passage 2 of younger and elderly donors. Gene expression data of these samples have been previously deposited unter GSE9593 and GSE12274.