Involvement of insulin-like growth factor-I and insulin-like growth factor binding proteins in pro-B-cell development.
Exp Hematol 2006;
34:508-18. [PMID:
16569597 DOI:
10.1016/j.exphem.2006.01.009]
[Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2005] [Revised: 12/12/2005] [Accepted: 01/12/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE
Insulin-like growth factor (IGF)-binding proteins (IGFBPs) are a family of proteins thought to modulate IGF function. By employing an in vitro culture system of human hematopoietic stem cells cocultured with murine bone marrow stromal cells, we examined the effects of IGF-I and IGFBPs on early B-cell development.
MATERIALS AND METHODS
Human CD34(+) bone marrow cells were cocultured with murine stromal MS-5 cells for 4 weeks, and pro-B-cell number was analyzed by flow cytometry. After administration of reagents that are supposed to modulate IGF-I or IGFBP function to the culture, the effect on pro-B-cell development was examined.
RESULTS
After cultivation for 4 weeks, effective induction of pro-B-cell proliferation was observed. Experiments using several distinct factors, all of which neutralize IGF-I function, revealed that impairment of IGF-I function results in a significant reduction in pro-B-cell development from CD34(+) cells. In addition, when the effect of recombinant proteins of IGFBPs and antibodies against IGFBPs were tested, IGFBP-3 was found to inhibit pro-B-cell development, while IGFBP-6 was required for pro-B-cell development.
CONCLUSIONS
IGF-I is essential for development of bone marrow CD34(+) cells into pro-B cells. Moreover, IGFBPs are likely involved in regulation of pro-B-cell development.
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