Regulation of myeloproliferation and M2 macrophage programming in mice by Lyn/Hck, SHIP, and Stat5
Wenbin Xiao, … , Clifford A. Lowell, Toshiaki Kawakami
Wenbin Xiao, … , Clifford A. Lowell, Toshiaki Kawakami
Published February 1, 2008
Citation Information: J Clin Invest. 2008;118(3):924-934. https://doi.org/10.1172/JCI34013.
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Research Article Hematology

Regulation of myeloproliferation and M2 macrophage programming in mice by Lyn/Hck, SHIP, and Stat5

Abstract

The proliferation and differentiation of hematopoietic stem cells (HSCs) is finely regulated by extrinsic and intrinsic factors via various signaling pathways. Here we have shown that, similar to mice deficient in the lipid phosphatase SHIP, loss of 2 Src family kinases, Lyn and Hck, profoundly affects HSC differentiation, producing hematopoietic progenitors with increased proliferation, reduced apoptosis, growth factor–independent survival, and skewed differentiation toward M2 macrophages. This phenotype culminates in a Stat5-dependent myeloproliferative disease that is accompanied by M2 macrophage infiltration of the lung. Expression of a membrane-bound form of SHIP in HSCs lacking both Lyn and Hck restored normal hematopoiesis and prevented myeloproliferation. In vitro and in vivo studies suggested the involvement of autocrine and/or paracrine production of IL-3 and GM-CSF in the increased proliferation and myeloid differentiation of HSCs. Thus, this study has defined a myeloproliferative transformation-sensitive signaling pathway, composed of Lyn/Hck, SHIP, autocrine/paracrine cytokines, and Stat5, that regulates HSC differentiation and M2 macrophage programming.

Authors

Wenbin Xiao, Hong Hong, Yuko Kawakami, Clifford A. Lowell, Toshiaki Kawakami

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Figure 5

Stat5 activation is required for the increased proliferation and macrophage differentiation of SHIP–/– KSL cells.

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Stat5 activation is required for the increased proliferation and macroph...
(A) KSL CD34– cells derived from WT and SHIP–/– mice were sorted into a 96-well plate containing SCF, Flt3 ligand, and IL-11 and cultured for 3 days. *P < 0.05 between WT and mutant. (B) Colony-forming assays showed skewed differentiation of KSL cells of SHIP–/– mice into macrophages in the presence of IL-3, IL-6, SCF, and erythropoietin (left panel). SHIP–/– KSL cells formed colonies in the absence of growth factors (right panel). (C–E) Stat5 in SHIP–/– c-Kit+Lin– cells (C) and F4/80+ lung macrophages (C–E) was constitutively activated, as shown by flow cytometry (C), immunohistochemistry (D), and confocal microscopy (E) using anti–p-Stat5 (Tyr694). Original magnification, ×400 (D and E). (F and G) SHIP–/– and WT KSL cells were transduced with a bicistronic retroviral vector encoding DN Stat5, DN Stat3, or empty vector, together with GFP, and cultured in SCF, Flt3 ligand, and IL-11. Ratios of cell numbers normalized against those of empty vector–transduced cells are plotted. #P < 0.05 compared with cells transduced with empty vector. (F). Transduced cells (150 cells seeded) were cultured to form colonies in methylcellulose medium containing IL-3, IL-6, SCF, and erythropoietin (G).