Hierarchical organization of osteoblasts reveals the significant role of CD166 in hematopoietic stem cell maintenance and function

► ALCAM/CD166 expression in CD45 −CD31 −Ter119 −Sca1 − osteoblasts increases during the first week of culture and then dramatically declines with culture duration. ► ALCAM/CD166 expression in osteoblasts directly correlates with hematopoietic activity and function of LSK cells co-cultured with osteoblasts. ► LSK cells co-cultured with Lin −OPN + CD166 + CD44 + CD90 + osteoblasts sustain the highest in vivo repopulating potential in primary and secondary recipients.