DNA methylation in AZA+/AZA- mesenchymal stromal cells (MSCs) from patients with chronic myelomonocytic leukemia or healthy individuals

DNA methylation is a fundamental epigenetic modification regulating gene expression. Aberrant DNA methylation may be involved in the transcriptionally/functionally altered CMML-MSCs. However, understanding the overall DNA methylation profile in MSCs and its changes after the intervention of demethylating drugs such as AZA is still lacking. In this present study, In vitro expanded MSCs from CMML patients (n=10) and healthy individuals (n=5) were treated with AZA or DMSO, and then used for DNA methylation profiling (EPIC) respectively. A total of 30 MSC samples were included. MSCs. Our study reveals that MSCs from different individual cohorts (healthy vs. CMML) exhibit significantly different sensitivity and reactivity to AZA. AZA treatment in vitro modulates aberrant DNA methylation profiles in CMML-MSCs and restores their impaired support for healthy hematopoiesis. Our study shows that the therapeutic effect of AZA on CMML patients is not limited to its inhibitory effect on malignant clones, but also manifested in its regulatory effect on the damaged bone marrow stromal microenvironment. Targeted improvement of bone marrow microenvironment may be a potential way to improve and restore normal hematopoiesis in patients with CMML. Bisulphite converted DNA from the 30 samples were hybridised to the Illumina Infinium MethylationEPIC (850K) Beadchip