CD146 expression on primary non-hematopoietic bone marrow stem cells correlates to in situ localization.
Nummer: Mar 17
Non-hematopoietic bone marrow mesenchymal stem cells (BM-MSC) are of central importance for bone marrow stroma and the hematopoietic environment. However, the exact phenotype and anatomical distribution of specified MSC populations in the marrow are unknown. We have characterized the phenotype of primary human BM-MSC and found that all assayable CFU-F were highly and exclusively enriched not only in the lin(-)/CD271(+)/CD45(-)/CD146(+) stem cell fraction, but also in lin(-)/CD271(+)/CD45(-)/CD146(-/low) cells. Both populations, regardless of CD146 expression, shared a similar phenotype and genotype, gave rise to typical cultured stroma cells, and formed bone and hematopoietic stroma in vivo. Interestingly, CD146 was up-regulated in normoxia, and down-regulated in hypoxia. This correlated to in situ localization differences with CD146 co-expressing reticular cells located in perivascular regions, whereas bone-lining MSC expressed CD271 alone. In both regions, CD34(+) hematopoietic stem/progenitor cells were located in close proximity to MSC. These novel findings show that the expression of CD146 differentiates between perivascular versus endosteal localization of non-hematopoietic bone marrow stem cell populations, which has apparent implications for the study of the hematopoietic environment.
- Medicine and Health Sciences
- ISSN: 1528-0020