Moreover, in adult progenitors, Flt3-ITD induces self-renewal in a STAT5-dependent manner [36]

Moreover, in adult progenitors, Flt3-ITD induces self-renewal in a STAT5-dependent manner [36]. been evaluated in clinical trials; however, the use of Flt3-ITD inhibitors as single agents resulted in poor clinical outcome due Timosaponin b-II to emergence of drug-resistant cells [5]. This underscores the need to develop combination treatment strategies [6]. Therefore, it is important to identify pathways regulated by the activated Flt3 receptor for the development of new treatment targets. Several pathways have been implicated downstream of the mutated Flt3 receptor in leukemias, including the Wnt pathway and the JAK/STAT pathway [7, 8]. Interestingly, the oncogenes have been implicated downstream of Flt3-ITD signaling [9]. The family genes, including genes and concomitant downregulation of the Myc antagonists, the genes, in different hematopoietic stem and progenitor cell subpopulations, as well as downregulation of the Mxd-related gene and the transcriptional activator and upregulation of the Myc antagonists < 0.05, ??< 0.01). 3. Results 3.1. Myeloid Progenitor and Hematopoietic Stem Cell Populations Are Changed in Flt3-ITD Mice To evaluate the gene expression of the network genes in the bone marrow of Flt3-ITD mice compared with wild-type (WT) mice, hematopoietic stem cell and myeloid progenitor (MPP) subpopulations were identified by staining for surface markers, analyzed by fluorescence-activated cell sorting (FACS), and subsequently sorted. Initially, myeloid progenitors including pre-GM and granulocytic myeloid progenitors (GMPs), as well as Lin?Sca-1+Kit+ (LSK) cells, within which hematopoietic stem cells reside, were sorted using a staining procedure including endoglin and the SLAM receptor CD150, as described previously [23]. The Flt3-ITD mouse has a myeloproliferative disease with expanded myeloid populations [19]. Consistently, we observed that myeloid progenitors (MPs/LK; Lin?Sca-1?Kit+ cells) in Flt3-ITD mice are increased PRKACA to 69.5% in comparison with 54.9% MPs in WT mice (Figure 1(a)). Moreover, we observed that the relative distribution of subpopulations within the MP compartment was altered as well. Importantly, progenitors of the granulocytic/monocytic pathway (pre-GM and GMPs) were increased in Flt3-ITD mice in comparison to WT mice, as we observed that pre-GMs were increased Timosaponin b-II from 39% in WT to 65% in Flt3-ITD mice and GMPs were increased from 41% in WT to 86% in ITD mice (Figure 1(a)). Consistent with our previous data [24], the progenitors of the megakaryocytic and erythroid pathway were diminished (Figure 1(a)). The expression of Flt3 is altered or diminished due to the ITD mutation; therefore, staining to identify HSC subpopulations by utilizing the expression of the Flt3 receptor is not feasible. Here, we identified long-term (LT-) HSCs as CD150+CD105+ utilizing CD150 and endoglin (CD105), while MPPs were identified as CD150?/CD105+. Intriguingly, we observed a decrease in LT-HSCs in favor of MPPs in the ITD mice (Figure 1(b)). Collectively, the above data set indicates that ITD mutation in Timosaponin b-II Flt3 results in the expansion of Timosaponin b-II the pre-GM, GMP, and MPP compartments. Open in a separate window Figure 1 Myeloid progenitor and hematopoietic stem cell populations are changed in Flt3-ITD mice. Analysis of hematopoietic stem cell (HSC) and multipotent progenitor (MPP) subpopulations within the Lin?Sca-1+Kit+ (LSK) population, as well as myeloid progenitors including pre-GM and granulocytic myeloid progenitors (GMPs), in the bone marrow of Flt3-ITD and wild-type (WT) mice, was performed using a staining procedure including endoglin and the SLAM receptor CD150. 3.2. Myeloid and Multipotent Progenitors Have Altered Myc Network Genes.