Developmental differences in IFN signaling affect GATA1s-induced megakaryocyte hyperproliferation
Andrew J. Woo, … , Jonghwan Kim, Alan B. Cantor
Andrew J. Woo, … , Jonghwan Kim, Alan B. Cantor
Published July 1, 2013
Citation Information: J Clin Invest. 2013;123(8):3292-3304. https://doi.org/10.1172/JCI40609.
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Research Article Hematology

Developmental differences in IFN signaling affect GATA1s-induced megakaryocyte hyperproliferation

Abstract

About 10% of Down syndrome (DS) infants are born with a transient myeloproliferative disorder (DS-TMD) that spontaneously resolves within the first few months of life. About 20%–30% of these infants subsequently develop acute megakaryoblastic leukemia (DS-AMKL). Somatic mutations leading to the exclusive production of a short GATA1 isoform (GATA1s) occur in all cases of DS-TMD and DS-AMKL. Mice engineered to exclusively produce GATA1s have marked megakaryocytic progenitor (MkP) hyperproliferation during early fetal liver (FL) hematopoiesis, but not during postnatal BM hematopoiesis, mirroring the spontaneous resolution of DS-TMD. The mechanisms that underlie these developmental stage–specific effects are incompletely understood. Here, we report a striking upregulation of type I IFN–responsive gene expression in prospectively isolated mouse BM- versus FL-derived MkPs. Exogenous IFN-α markedly reduced the hyperproliferation FL-derived MkPs of GATA1s mice in vitro. Conversely, deletion of the α/β IFN receptor 1 (Ifnar1) gene or injection of neutralizing IFN-α/β antibodies increased the proliferation of BM-derived MkPs of GATA1s mice beyond the initial postnatal period. We also found that these differences existed in human FL versus BM megakaryocytes and that primary DS-TMD cells expressed type I IFN–responsive genes. We propose that increased type I IFN signaling contributes to the developmental stage–specific effects of GATA1s and possibly the spontaneous resolution of DS-TMD.

Authors

Andrew J. Woo, Karen Wieland, Hui Huang, Thomas E. Akie, Taylor Piers, Jonghwan Kim, Alan B. Cantor

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Figure 1

Flow cytometric sorting of MkPs from adult BM and E13.5 FL.

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Flow cytometric sorting of MkPs from adult BM and E13.5 FL. (A and B) FA...
(A and B) FACS plots and gates used for cell sorting. Cells were stained with antibodies against lineage markers, c-KIT, Sca-1, CD41, and CD150. Dead cells were identified by staining with DAPI and were excluded. May-Grünwald-Giemsa stains of cytospun freshly sorted BM and FL MkPs are also shown (original magnification, ×1,000). (A) Percent BM-MkPs gated relative to the starting population was as follows: P3, 17%; P4, 16.5%; P5, 1.9%. (B) Percent FL-MkPs gated relative to the starting population was as follows: P3, 38.2%; P4, 24.4%; P5, 1.2%. (C) Colony-forming assays. Percentage of colony type from sorted or unsorted BM and FL cells cultured in semisolid medium (after red blood cell lysis) containing TPO, erythropoietin, stem cell factor, IL-3, IL-11, and GM-CSF. Colonies were enumerated after 8 days. Cell accumulations of 3 or more cells were considered a colony. (D) Representative Mk colonies (unstained) from BM (day 7 of culture) or FL (day 8 of culture). Original magnification, ×100.