A systems biology approach for defining the molecular framework of the hematopoietic stem cell niche

Hematopoietic stem/progenitor cells (HSPCs) are at the basis of the hematopoietic hierarchy. Their ability to self-renew and differentiate is strictly controlled by molecular signals produced by their surrounding micorenvironments composed of stromal cells. HSPCs first emerge in the AGM (Aorta Gonads Mesonephros) region, amplify in the fetal liver (FL) and are maintained in the adult bone marrow (BM). To further characterize the molecular program of the HSPC niches, we have compared the global transcriptome of HSPC-supportive and non/less-supportive stromal clones established from the AGM, FL and BM. We took advantage of stromal clones established from the AGM, FL and BM and tested for their ability to support or not HSPCs ex vivo. RNA were extracted from confluent stromal cultures or sorted cells and used for hybridization of Affymetrix (mouse gene 1.0 ST) microarrays.