In vivo interleukin-1 (IL-1) administration indirectly promotes type II IL-1 receptor expression on hematopoietic bone marrow cells: novel mechanism for the hematopoietic effects of IL-1.
Interleukin-1 (IL-1) has profound stimulatory effects on hematopoiesis but the mechanism(s) of action remain unknown. The direct action of IL-1 on hematopoietic progenitor cells requires the presence of a specific IL-1 receptor (IL-1R). In this report, we tested the effect of in vivo IL-1 treatment on the expression of IL-1R on bone marrow (BM) cells. Injection of mice with IL-1 results in a marked upregulation of IL-1R on light-density BM cells as on a subpopulation enriched for myeloid precursors. Pretreatment of mice with anti-type I IL-1R antibody (35F5), which has been shown to prevent the radioprotective effect of IL-1, also blocked IL-1-induced IL-1R expression on BM cells. This antibody did not directly bind and block IL-1 binding to the type II IL-1R expressed on hematopoietic cells, suggesting that IL-1R upregulation by IL-1 is indirect. It is therefore possible that IL-1 acts on type I IL-1R-expressing accessory cells such as stromal cells or T cells to induce production of hematopoietic growth factors (HGFs). In support of this, granulocyte colony-stimulating factor administration can induce the increase of IL-1R on BM cells. Thus, the increased expression of IL-1R on hematopoietic BM cells by IL-1 is indirect, probably mediated in part through endogenous HGF production. These results also suggest that the restorative hematopoietic effect of IL-1 occurs through both indirect and direct mechanisms.
Dubois
C M
CM
Program Resources, Inc/DynCorp, National Cancer Institute-Frederick Cancer Research and Development Center, MD.
Ruscetti
F W
FW
Keller
J R
JR
Oppenheim
J J
JJ
Hestdal
K
K
Chizzonite
R
R
Neta
R
R
D000818:Animals; D001854:Bone Marrow Cells; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D006410:Hematopoiesis / Q000187:drug effects*; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology; D008297:Male; D051379:Mice; D011971:Receptors, Immunologic / Q000378:metabolism*; D017472:Receptors, Interleukin-1; D015854:Up-Regulation
D007375:Interleukin-1; D011971:Receptors, Immunologic; D017472:Receptors, Interleukin-1; D016179:Granulocyte Colony-Stimulating Factor; D015847:Interleukin-4; D007371:Interferon-gamma