Epigenetic and in vivo comparison of diverse mesenchymal stromal cell sources reveals an endochonrdal signature for human hematopoietic niche formation. Homo sapiens

Despite similarities in morphology, phenotype and in vitro behavior, Mesenchymal Stromal Cells (MSC) form various tissue sources show striking differences in their in vivo potential to form bone, cartilage and hematopoietic support tissue. Comparing four commonly use MSC sources (bone marrow (BM), white adipose tissue (WAT), umbilical cord (UC) and skin) we found only bone marrow (BM)-derived MSCs capable of endochondral ossification and marrow attraction. To gain mechanistic insights explaining this differences we analyzed gene expression characteristics of MSC from all four tissue sources using Affymetrix Genechip Human Gene 2.0 ST Array. Overall design: MSCs from BM, WAT, UC and skin were isolated using plastic adherence. Cells were expanded in standard alpha-MEM supplemented with pooled human platelet lysate fully replacing fetal bovine serum. MSCs were subcutaneously implanted into immune-compromised mice to comparatively evaluate bone formation and subsequent bone marrow attraction. In parallel we have isolated RNA from all sources to analyze tissue source specific gene expression profile.