Extracellular vesicles from myelodysplastic mesenchymal stromal cells induce DNA damage and mutagenesis of hematopoietic stem cells through miRNA transfer
Résumé
Physiopathology of myelodysplastic syndrome (MDS) remains poorly understood and the role of the microenvironment is increasingly highlighted. Recent studies in mouse models demonstrate that abnormalities of mesenchymal stromal cells (MSC) contribute to the physiopathology of MDS. In particular, genetic deletion of dicer1, a gene encoding a type III RNase essential for the genesis of miRNA, in murine MSC-derived osteoprogenitors led to a pathological microenvironment generating myelodysplastic features in hematopoietic progenitors and ultimately leading to acute myeloid leukemia [1]. In human, there is an increased susceptibility to senescence of the MDS mesenchymal stem cells and defects in the support properties of the growth of hematopoietic stem cells (HSC) [2]. These observations establish a causal relationship between deregulation of the hematopoietic niche and MDS pathogenesis. However, so far only few studies have addressed the mechanisms by microenvironmental MSC and HSC exchange signals that may interfere with miRNA processing, specifically in the human MDS microenvironment.