Lymphoid priming in human bone marrow begins before expression of CD10 with upregulation of L-selectin.

Department of Pathology & Laboratory Medicine, University of California, Los Angeles, California, USA.
Nature Immunology (Impact Factor: 24.97). 09/2012; 13(10):963-71. DOI: 10.1038/ni.2405
Source: PubMed

ABSTRACT Expression of the cell-surface antigen CD10 has long been used to define the lymphoid commitment of human cells. Here we report a unique lymphoid-primed population in human bone marrow that was generated from hematopoietic stem cells (HSCs) before onset of the expression of CD10 and commitment to the B cell lineage. We identified this subset by high expression of the homing molecule L-selectin (CD62L). CD10(-)CD62L(hi) progenitors had full lymphoid and monocytic potential but lacked erythroid potential. Gene-expression profiling placed the CD10(-)CD62L(hi) population at an intermediate stage of differentiation between HSCs and lineage-negative (Lin(-)) CD34(+)CD10(+) progenitors. CD62L was expressed on immature thymocytes, and its ligands were expressed at the cortico-medullary junction of the thymus, which suggested a possible role for this molecule in homing to the thymus. Our studies identify the earliest stage of lymphoid priming in human bone marrow.

  • [Show abstract] [Hide abstract]
    ABSTRACT: B lymphocytes differentiate from hematopoietic stem cells through a series of distinct stages. Early B cell development proceeds in bone marrow until immature B cells migrate out to secondary lymphoid tissues, such as a spleen and lymph nodes, after completion of immunoglobulin heavy and light chain rearrangement. Although the information about the regulation by numerous factors, including signaling molecules, transcription factors, epigenetic changes and the microenvironment, could provide the clinical application, our knowledge on human B lymphopoiesis is limited. However, with great methodological advances, significant progress for understanding B lymphopoiesis both in human and mouse has been made. In this review, we summarize the experimental models for studies about human adult B lymphopoiesis, and the role of microenvironment and signaling molecules, such as cytokines, transforming growth factor-β superfamily, Wnt family and Notch family, with point-by-point comparison between human and mouse.
    World journal of stem cells. 09/2014; 6(4):421-31.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Although the role for the individual Notch receptors in early hematopoiesis have been thoroughly investigated in mouse, studies in human have been mostly limited to the use of pan-Notch inhibitors. However, such studies in human are important to predict potential side effects of specific Notch receptor blocking reagents because these are currently being considered as therapeutic tools to treat various Notch-dependent diseases. In this study, we studied the individual roles of Notch1 and Notch3 in early human hematopoietic lineage decisions, particularly during T-lineage specification. Although this process in mice is solely dependent on Notch1 activation, we recently reported Notch3 expression in human uncommitted thymocytes, raising the possibility that Notch3 mediates human T-lineage specification. Although expression of a constitutive activated form of Notch3 (ICN3) results in the induction of T-lineage specification in human CD34(+) hematopoietic progenitor cells, similar to ICN1 overexpression, loss-of-function studies using blocking Abs reveal that only Notch1, but not Notch3, is critical in this process. Blocking of Notch1 activation in OP9-DLL4 cocultures resulted in a complete block in T-lineage specification and induced monocytic and plasmacytoid dendritic cell differentiation instead. In fetal thymus organ cultures, impeded Notch1 activation resulted in B and dendritic cell development. In contrast, Notch3 blocking Abs only marginally affected T-lineage specification and hematopoietic differentiation with a slight increase in monocyte development. No induction of B or dendritic cell development was observed. Thus, our results unambiguously reveal a nonredundant role for Notch1 in human T-lineage specification, despite the expression of other Notch receptors.
    Journal of immunology (Baltimore, Md. : 1950). 11/2014;
  • Source


Available from