Abstract 20010: Diet-induced Obesity Stimulates Inflammatory Monopoiesis From Hematopoietic Stem Progenitor Cells Through Activating Histone Methylation

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Milie Fang ◽  
Rita Mirza ◽  
Timothy J Koh ◽  
Norifumi Urao

Obesity-induced monopoiesis has been implicated in the development of obesity-related complications. Monopoiesis is largely dependent on hematopoietic stem progenitor cells (HSPCs) in the bone marrow (BM). However, little is known about hematopoietic control mechanisms in diet-induced obesity. In a mouse model of diet-induced obesity (DIO), we found leukocytosis (9.465 ± 0.7350 K/ul versus 7.277 ± 0.3450 K/ul in healthy controls, n=7 each? , p=0.023) and increased inflammatory Ly6Chi monocytes in circulation (377.2 ± 40.94/ul vs. 224.8 ± 39.18/ul in lean control; n=7; p=0.023), associated with increased myeloid progenitor cells (60% increase in granulocyte-monocyte progenitor cells, n=4) in the BM. By flow cytometry based profiling, we found that active marks for transcription, histone 3 lysine 4 trimethylation (H3K4me3), are upregulated (1.82-fold increase in mean fluorescent intensity (MFI) vs. lean mice, n=5, p<0.05) in Ly6Chi inflammatory monocytes in DIO mice, along with increased inflammatory gene expression in response to TLR (toll-like receptor) 4 stimulation. In the BM, HSPCs but not myeloid progenitor cells have enriched H3K4me3 in DIO mice (2.84-fold in MFI in cKit+Sca1+Lin- cells, n=5, p<0.05). This activated mark in HSPCs is associated with increased monopoiesis from HSPCs (1.55-fold increase in output CD11b+Ly6Chi monocytes from cultured HSPCs, n=3-5, p<0.01) in response to TLR2 and TLR4 stimulations. Of note, HSPCs produce inflammatory cytokines to promote differentiation into inflammatory monocytes. Moreover, HIF-1a, a potential upstream of H3K4me3, is upregulated (2.29-fold in MFI, n=5, p<0.05) in HSPCs in DIO mice. These results suggest that obesity increases HIF-1a-mediated H3K4me3 enrichment in HSPCs, which in turn contributes to inflammatory cytokine expression and to increased inflammatory monopoiesis. Thus, epigenetic marks in HSPCs could be a target for obesity-related complications.

Blood ◽  
1992 ◽  
Vol 79 (9) ◽  
pp. 2229-2236 ◽  
Author(s):  
MJ Robertson ◽  
RJ Soiffer ◽  
AS Freedman ◽  
SL Rabinowe ◽  
KC Anderson ◽  
...  

Abstract The CD33 antigen, identified by murine monoclonal antibody anti-MY9, is expressed by clonogenic leukemic cells from almost all patients with acute myeloid leukemia; it is also expressed by normal myeloid progenitor cells. Twelve consecutive patients with de novo acute myeloid leukemia received myeloablative therapy followed by infusion of autologous marrow previously treated in vitro with anti-MY9 and complement. Anti-MY9 and complement treatment eliminated virtually all committed myeloid progenitors (colony-forming unit granulocyte- macrophage) from the autografts. Nevertheless, in the absence of early relapse of leukemia, all patients showed durable trilineage engraftment. The median interval post bone marrow transplantation (BMT) required to achieve an absolute neutrophil count greater than 500/microL was 43 days (range, 16 to 75), to achieve a platelet count greater than 20,000/microL without transfusion was 92 days (range, 35 to 679), and to achieve red blood cell transfusion independence was 105 days (range, 37 to 670). At the time of BM harvest, 10 patients were in second remission, one patient was in first remission, and one patient was in third remission. Eight patients relapsed 3 to 18 months after BMT. Four patients transplanted in second remission remain disease-free 34+, 37+, 52+, and 57+ months after BMT. There was no treatment-related mortality. Early engraftment was significantly delayed in patients receiving CD33-purged autografts compared with concurrently treated patients receiving CD9/CD10-purged autografts for acute lymphoblastic leukemia or patients receiving CD6-purged allografts from HLA- compatible sibling donors. In contrast, both groups of autograft patients required a significantly longer time to achieve neutrophil counts greater than 500/microL and greater than 1,000/microL than did patients receiving normal allogeneic marrow. CD33(+)-committed myeloid progenitor cells thus appear to play an important role in the early phase of hematopoietic reconstitution after BMT. However, our results also show that human marrow depleted of CD33+ cells can sustain durable engraftment after myeloablative therapy, and provide further evidence that the CD33 antigen is absent from the human pluripotent hematopoietic stem cell.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1572-1572
Author(s):  
Chirag Shah ◽  
Hao Wang ◽  
Elizabeth A. Eklund

Abstract Abstract 1572 HoxA10 is a homeodomain transcription factor which functions as a myeloid leukemia promoter. Correlative clinical studies found that increased expression of a group of HoxA proteins, including HoxA10, in acute myeloid leukemia (AML) was associated with poor prognosis. In murine models, overexpression of HoxA10 in the bone marrow was associated with development of a myeloproliferative disease which progressed to AML with time. These results suggested that HoxA10-overexpression dysregulated cell proliferation and/or survival, and predisposed to acquisition of additional mutations which led to differentiation block and AML. Additional investigations, we and others demonstrated that HoxA10 overexpression in murine hematopoietic stem cells (HSC) expanded the granulocyte/monocyte progenitor (GMP) population in vitro and in vivo. Despite this information about the impact of HoxA10 overexpression on myeloid leukemogenesis, the mechanisms by which HoxA10 exerts this effect are largely unknown. To investigate such mechanisms, we have been identifying HoxA10 target genes. In previous studies, we identified a number of HoxA10 target genes that encode phagocyte effector proteins. HoxA10 represses transcription of these gene in myeloid progenitors, and decreased HoxA10 repression activity contributes to phenotypic differentiation as myelopoiesis proceeds. This provided a potential mechanism for HoxA10 involvement in differentiation block, but not progenitor survival or expansion. We used a chromatin immuno-precipitation based approach to identify additional HoxA10 target genes involved in these activities. Previously, we reported that HoxA10 activated the DUSP4 gene in myeloid progenitor cells. This gene encodes Mitogen Activated Protein Kinase Phosphatase 2 (Mkp2) which inhibits Jnk-induced apoptosis in myeloid progenitor cells. This provided a mechanism for increased cell survival in HoxA10-overexpressing cells. In the current studies, we identified TGFB2 as a HoxA10 target gene. This gene encodes Transforming Growth Factor Beta 2 (TgfB2) a member of the TgfB super family of cytokines. Similar to TgfB1 and 3, TgfB2 interacts with TgfB-receptors I and II. However, unlike these more classical family members, TgfB2 induces proliferation of hematopoietic stem and progenitor cells. We found that HoxA10 activated the TGFB2 promoter via tandem cis elements in the proximal promoter. This resulted in autocrine stimulation of proliferation in HoxA10-overexpressing GMP and leukemia cells in vitro. Increased proliferation in HoxA10-overexpressing cells involved activation of the MAP kinase pathway in a TgfB2 dependent manner. These studies identify autocrine production of pro-proliferative cytokines as a novel mechanism for the function of Hox proteins. These findings have implications for ex vivo expansion of HSC and myeloid progenitors for tissue engineering. These result also have implications for therapeutic approaches to poor prognosis AML characterized by increased Hox expression. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2634-2634
Author(s):  
Hui Luo ◽  
Jennifer A. Cain ◽  
AnnaLynn Molitoris ◽  
Joseph Opferman ◽  
Michael H. Tomasson

Abstract Ectopic expression of Myc in most primary cell types induces apoptosis, and cancer development typically requires additional, anti-apoptotic mutations. We reported previously that ectopic expression of Myc in unfractionated murine bone marrow cells induced rapid onset acute myeloid leukemia (AML) without detectable anti-apoptotic mutations. We hypothesized that AML developed in our model because a subset of normal primary bone marrow cells were inherently resistant to Myc-induced apoptosis. Consistent with this model, seven days of Myc activation in the bone marrow of mice caused the reduction of B-lineage cells while at the same time inducing the expansion of myeloid lineage cells. We sought to determine the mechanism by which myeloid progenitor cells evaded Myc-induced apoptosis, and found that Myc-induced AML cells exhibited a distinct profile of pro- and anti-apoptotic proteins, including high levels of the anti-apoptotic Bcl-2 family member Mcl-1. To prioritize apoptosis genes, we examined AML patient microarray data and found MCL1 to be uniformly expressed at high levels in human AML (94/94, 100%). We used Mcl1 heterozygous mice (Mcl1F/null) as bone marrow donors for transduction-transplantation experiments and found that, compared with Mcl1 wild-type (median survival=60 days), haploinsufficiency for Mcl1 completely protected mice from Myc-induced AML (median survival not reached). Mice transplanted with Mcl1F/null cells co-expressing Myc and Bcl2 succumbed rapidly to disease (median survival 25 days). In wild-type mice, defined hematopoietic stem and myeloid progenitor cell populations were not significantly increased by Myc activation. However, Myc transduction conferred serial replating ability to sorted hematopoietic stem and progenitor cells including lineage-committed (Lin+Kit+) progenitors cells. These data demonstrate a critical role for Mcl1 in our AML model and suggest that dysregulation of MYC in MCL1-expressing progenitor cells may mediate AML pathogenesis in humans.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3038-3038
Author(s):  
Jos Domen ◽  
Mastura Wahedi ◽  
Esther Danenberg ◽  
Stephanie Smith-Berdan ◽  
Julie Christensen ◽  
...  

Abstract Neutropenia induced by chemotherapy, hematopoietic cell transplantation, as well as radiation-induced neutropenia is accompanied by a significant morbidity and mortality due to increased susceptibility to a variety of pathogens. Despite clinical advances, such as the availability of growth factors that can stimulate granulopoiesis, like G-CSF, and new generations of antibiotics and antifungal agents, the problem persists. Direct cellular therapy with mature granulocytes has met with limited success, and would be difficult to implement due to the large number of cells needed, their very short lifespan and the inability to store the cells between harvesting and use. Our long-term goal is to develop a non-HLA-restricted cell-based short-term bridging therapy to reduce susceptibility to infection and enhance recovery from infections in the setting of neutropenia. The recent characterization of surface marker profiles of early myeloid progenitors has allowed the prospective testing of these cells. It has been clearly shown that the use of limited numbers of a combination of Common Myeloid Progenitors (CMP) and Granulocyte-Macrophage-Progenitors (GMP), purified from bone marrow, can protect mice from a normally lethal challenge with fungus or bacteria [Blood100:4660-7(2002)]. We have extended these observations and tested whether myeloid progenitors (MP) with similar properties can be obtained in large numbers from hematopoietic stem cells (HSC) in vitro. Here we report that a one week, serum-free culture can result in a 200-fold expansion of cells with myeloid progenitor activity with respect to the starting CD117+, CD90.1low, Linneg/low and Sca-1+ KTLS-HSC. Furthermore, these myeloid progenitor cells are as effective as Myeloid Progenitors sorted directly from bone marrow in preventing death due to invasive aspergillosis, even when the cells are fully allogeneic and have been cryopreserved prior to use. These results indicate a way in which myeloid progenitor cells, which can be stored frozen prior to use, can be obtained in large numbers. This process, once translated to human cells, would also open the way for the stockpiling of MP for use in nuclear disasters.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3537-3537
Author(s):  
Ling Bei ◽  
Chirag Shah ◽  
Hao Wang ◽  
Elizabeth Eklund

Abstract Leukemias with chromosomal translocation or partial tandem duplications involving the MLL (mixed lineage leukemia) gene have exceptionally poor prognosis (referred to as 11q23-leukemias). At the molecular level, 11q23-leukemias are characterized by aberrant expression of a set of homeodomain transcription factors in hematopoietic stem cells (HSC) and differentiating myeloid progenitor cells. This transcription factor set includes HoxB3, B4, A7-11, Cdx2-4 and Meis1. Cdx and Hox proteins are involved in regulating hematopoiesis. Transcription of HOX and CDX genes decreases normal myelopoiesis, but is aberrantly sustained in 11q23-leukemias. Cdx4 activates transcription of the HOXA9 and HOXA10 genes, and HoxA10 activates CDX4 transcription. The events that break this feedback loop, permitting a decrease in Cdx4-expression during normal myelopoiesis, were previously undefined. In the current study, we find that HoxA9 represses CDX4 transcription in differentiating myeloid cells; antagonizing activation by HoxA10. We determine that tyrosine phosphorylation of HoxA10 impairs transcriptional activation of CDX4, but tyrosine phosphorylation of HoxA9 facilitates repression of this gene. Since HoxA9 and HoxA10 are phosphorylated during myelopoiesis, this provides a mechanism for differentiation-stage-specific Cdx4 expression. HoxA9 and HoxA10 are increased in cells expressing Mll-Ell, a leukemia associated MLL1 fusion protein. We find that Mll-Ell induces a HoxA10-dependent increase in Cdx4-expression in myeloid progenitor cells. However, expression of Cdx4 decreases in a HoxA9-dependent manner upon exposure of Mll-Ell-expressing cells to differentiating cytokines. Leukemia associated, constitutively active mutants of Shp2 block cytokine-induced tyrosine phosphorylation of HoxA9 and HoxA10. In comparison to cells expressing Mll-Ell alone, we find that co-expression of Mll-Ell plus constitutively active Shp2 increases CDX4 transcription and Cdx4 expression in myeloid progenitor cells. And, increased Cdx4 expression is sustained upon exposure of these cells to differentiating cytokines. Our results identify a mechanism for increased and sustained CDX4 transcription in leukemias co-overexpressing HoxA9 and HoxA10 in combination with constitutive activation of Shp2. We also demonstrate that inhibition of Shp2-PTP activity decreases Cdx4 expression in Hox-overexpressing human myeloid leukemias. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2544-2544
Author(s):  
Naoki Hosen ◽  
Emmanuelle Passegue ◽  
Irving L. Weissman

Abstract For most leukemia the target cells of transforming mutations are still unknown. Here, we studied the developmental origin of t(8;21)-acute myeloid leukemia (AML), t(15;17)-acute promyelocytic leukemia (APL), and t(9;22)-chronic myeloid leukemia (CML). Purified mouse hematopoietic stem cells (HSCs) and various committed myeloid progenitor cells were retrovirally transduced with AML1/ETO, PML/RARα, or p210 BCR/ABL and subjected to in-vitro serial replating assay and in-vivo transplantation. Myeloid progenitors were efficiently immortalized in-vitro by AML1/ETO or PML/RARα as assayed in serial replating assays. However, following transplantation into lethally irradiated mice, neither AML1/ETO- nor PML/RARα-transduced myeloid progenitors were expanded in-vivo, although cells carrying the fusion gene DNA persisted well beyond their non-transduced control progenitors. In addition, 10 months after the transplant with transduced myeloid progenitor cells, PML/RARα but not AML1/ETO mRNA expression was still detected in committed myeloid progenitors, although PML/RARα-expressing cells were still not expanded. This finding demonstrates the ability of PML/RARα to increase the lifespan of committed myeloid progenitor cells both in-vitro and in-vivo and suggest that t(15;17)-APL could possibly evolve from persisting progenitor-derived cells. In contrast, BCR/ABL-expressing myeloid progenitors disappeared within 3 months post transplantation. Analysis of mice transplanted with transduced-HSCs demonstrated that AML1/ETO induced the accumulation of the most immature subset of HSCs (Lin-/c-kit+/Sca-1+/Flk-2-), while in contrast PML/RARα induced HSCs disappearance in most (5 out of 6) cases. In addition, we demonstrate that p210 BCR/ABL could induce the development of a CML-like disease from transduced HSCs (6 out of 16 cases), which is compatible with previous report. Together, these results suggest the existence of novel pre-leukemic stem cells (pre-LSCs) entities. Slowly expanding pre-LSCs could be generated from HSCs transformed by the expression of AML1/ETO. Persisting pre-LSCs could be generated from myeloid progenitors transformed by the expression of PML/RARα. These pre-LSC populations could mediate the early phases of t(8;21)-AML and t(15;17)-APL pathogenesis and could represent novel key targets for anti-leukemia therapies.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Fei Tang ◽  
Peng Zhang ◽  
Peiying Ye ◽  
Christopher A Lazarski ◽  
Qi Wu ◽  
...  

Adaptive autoimmunity is restrained by controlling population sizes and pathogenicity of harmful clones, while innate destruction is controlled at effector phase. We report here that deletion of Rptor in mouse hematopoietic stem/progenitor cells causes self-destructive innate immunity by massively increasing the population of previously uncharacterized innate myelolymphoblastoid effector cells (IMLECs). Mouse IMLECs are CD3-B220-NK1.1-Ter119- CD11clow/-CD115-F4/80low/-Gr-1- CD11b+, but surprisingly express high levels of PD-L1. Although they morphologically resemble lymphocytes and actively produce transcripts from Immunoglobulin loci, IMLECs have non-rearranged Ig loci, are phenotypically distinguishable from all known lymphocytes, and have a gene signature that bridges lymphoid and myeloid leukocytes. Rptor deletion unleashes differentiation of IMLECs from common myeloid progenitor cells by reducing expression of Myb. Importantly, IMLECs broadly overexpress pattern-recognition receptors and their expansion causes systemic inflammation in response to Toll-like receptor ligands in mice. Our data unveil a novel leukocyte population and an unrecognized role of Raptor/mTORC1 in innate immune tolerance.


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