1
|
Yamaguchi A, Hirano I, Narusawa S, Shimizu K, Ariyama H, Yamawaki K, Nagao K, Yamamoto M, Shimizu R. Blockade of the interaction between BMP9 and endoglin on erythroid progenitors promotes erythropoiesis in mice. Genes Cells 2021; 26:782-797. [PMID: 34333851 PMCID: PMC9290798 DOI: 10.1111/gtc.12887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 07/26/2021] [Accepted: 07/30/2021] [Indexed: 01/19/2023]
Abstract
Bone morphogenetic protein‐9 (BMP9), a member of the transforming growth factor β (TGFβ) superfamily, plays important roles in the development and maintenance of various cell lineages via complexes of type I and type II TGFβ receptors. Endoglin is a coreceptor for several TGFβ family members, including BMP9, which is highly expressed in a particular stage of differentiation in erythroid cells as well as in endothelial cells. Although the importance of the interaction between BMP9 and endoglin for endothelial development has been reported, the contribution of BMP9 to endoglin‐expressing erythroid cells remains to be clarified. To address this point, we prepared an anti‐BMP9 antibody that blocks the BMP9‐endoglin interaction. Of note, challenge with the antibody promotes erythropoiesis in wild‐type mice but not in a mouse model of renal anemia in which erythropoietin (EPO) production in the kidneys is genetically ablated. While endoglin‐positive erythroid progenitors are mainly maintained as progenitors when bone marrow‐derived lineage‐negative and cKit‐positive cells are cultured in the presence of EPO and stem cell factor, the erythroid‐biased accumulation of progenitors is impeded by the presence of BMP9. Our findings uncover an unrecognized role for BMP9 in attenuating erythroid differentiation via its interaction with endoglin on erythroid progenitors.
Collapse
Affiliation(s)
- Ayami Yamaguchi
- Nephrology Research Labs., Nephrology R&D Unit, R&D Division, Kyowa Kirin Co., Ltd., Machida, Japan
| | - Ikuo Hirano
- Department of Molecular Hematology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Shiho Narusawa
- Department of Molecular Hematology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kiyoshi Shimizu
- Nephrology Research Labs., Nephrology R&D Unit, R&D Division, Kyowa Kirin Co., Ltd., Machida, Japan
| | - Hiroyuki Ariyama
- Nephrology Research Labs., Nephrology R&D Unit, R&D Division, Kyowa Kirin Co., Ltd., Machida, Japan
| | - Kengo Yamawaki
- Nephrology Research Labs., Nephrology R&D Unit, R&D Division, Kyowa Kirin Co., Ltd., Machida, Japan
| | - Kenji Nagao
- Nephrology Research Labs., Nephrology R&D Unit, R&D Division, Kyowa Kirin Co., Ltd., Machida, Japan
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan.,Tohoku Medical Mega-Bank Organization, Tohoku University, Sendai, Japan
| | - Ritsuko Shimizu
- Department of Molecular Hematology, Tohoku University Graduate School of Medicine, Sendai, Japan.,Tohoku Medical Mega-Bank Organization, Tohoku University, Sendai, Japan
| |
Collapse
|
2
|
Abstract
Granulocytes are the major type of phagocytes constituting the front line of innate immune defense against bacterial infection. In adults, granulocytes are derived from hematopoietic stem cells in the bone marrow. Alcohol is the most frequently abused substance in human society. Excessive alcohol consumption injures hematopoietic tissue, impairing bone marrow production of granulocytes through disrupting homeostasis of granulopoiesis and the granulopoietic response. Because of the compromised immune defense function, alcohol abusers are susceptible to infectious diseases, particularly septic infection. Alcoholic patients with septic infection and granulocytopenia have an exceedingly high mortality rate. Treatment of serious infection in alcoholic patients with bone marrow inhibition continues to be a major challenge. Excessive alcohol consumption also causes diseases in other organ systems, particularly severe alcoholic hepatitis which is life threatening. Corticosteroids are the only therapeutic option for improving short-term survival in patients with severe alcoholic hepatitis. The existence of advanced alcoholic liver diseases and administration of corticosteroids make it more difficult to treat serious infection in alcoholic patients with the disorder of granulopoieis. This article reviews the recent development in understanding alcohol-induced disruption of marrow granulopoiesis and the granulopoietic response with the focus on progress in delineating cell signaling mechanisms underlying the alcohol-induced injury to hematopoietic tissue. Efforts in exploring effective therapy to improve patient care in this field will also be discussed.
Collapse
|
3
|
Jung HE, Shim YR, Oh JE, Oh DS, Lee HK. The autophagy Protein Atg5 Plays a Crucial Role in the Maintenance and Reconstitution Ability of Hematopoietic Stem Cells. Immune Netw 2019; 19:e12. [PMID: 31089439 PMCID: PMC6494762 DOI: 10.4110/in.2019.19.e12] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 01/17/2019] [Accepted: 01/21/2019] [Indexed: 12/19/2022] Open
Abstract
Hematopoietic stem cells (HSCs) in bone marrow are pluripotent cells that can constitute the hematopoiesis system through self-renewal and differentiation into immune cells and red blood cells. To ensure a competent hematopoietic system for life, the maintenance of HSCs is tightly regulated. Although autophagy, a self-degradation pathway for cell homeostasis, is essential for hematopoiesis, the role of autophagy key protein Atg5 in HSCs has not been thoroughly investigated. In this study, we found that Atg5 deficiency in hematopoietic cells causes survival defects, resulting in severe lymphopenia and anemia in mice. In addition, the absolute numbers of HSCs and multiple-lineage progenitor cells were significantly decreased, and abnormal erythroid development resulted in reduced erythrocytes in blood of Vav_Atg5−/− mice. The proliferation of Lin−Sca-1+c-Kit+ HSCs was aberrant in bone marrow of Vav_Atg5−/− mice, and mature progenitors and terminally differentiated cells were also significantly altered. Furthermore, the reconstitution ability of HSCs in bone marrow chimeric mice was significantly decreased in the presence of Atg5 deficiency in HSCs. Mechanistically, impairment of autophagy-mediated clearance of damaged mitochondria was the underlying cause of the HSC functional defects. Taken together, these results define the crucial role of Atg5 in the maintenance and the reconstitution ability of HSCs.
Collapse
Affiliation(s)
- Hi Eun Jung
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Ye Ri Shim
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Ji Eun Oh
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Dong Sun Oh
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.,Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Heung Kyu Lee
- Biomedical Science and Engineering Interdisciplinary Program, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.,Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea.,KAIST Institute for Health Science and Technology, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| |
Collapse
|
4
|
Cai X, Zheng Y, Speck NA. A Western Blotting Protocol for Small Numbers of Hematopoietic Stem Cells. J Vis Exp 2018. [PMID: 30199018 DOI: 10.3791/56855] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Hematopoietic stem cells (HSCs) are rare cells, with the mouse bone marrow containing only ~25,000 phenotypic long term repopulating HSCs. A Western blotting protocol was optimized and suitable for the analysis of small numbers of HSCs (500 - 15,000 cells). Phenotypic HSCs were purified, accurately counted, and directly lysed in Laemmli sample buffer. Lysates containing equal numbers of cells were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the blot was prepared and processed following standard Western blotting protocols. Using this protocol, 2,000 - 5,000 HSCs can be routinely analyzed, and in some cases data can be obtained from as few as 500 cells, compared to the 20,000 to 40,000 cells reported in most publications. This protocol should be generally applicable to other hematopoietic cells, and enables the routine analysis of small numbers of cells using standard laboratory procedures.
Collapse
Affiliation(s)
- Xiongwei Cai
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center; Department of Cell and Developmental Biology, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania; Department of Obstetrics and Gynecology, Southwest Hospital, Third Military Medical University
| | - Yi Zheng
- Division of Experimental Hematology, Cincinnati Children's Hospital Medical Center
| | - Nancy A Speck
- Department of Cell and Developmental Biology, Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania;
| |
Collapse
|
5
|
Lunger I, Fawaz M, Rieger MA. Single-cell analyses to reveal hematopoietic stem cell fate decisions. FEBS Lett 2017; 591:2195-2212. [PMID: 28600837 DOI: 10.1002/1873-3468.12712] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/19/2017] [Accepted: 06/02/2017] [Indexed: 12/15/2022]
Abstract
Hematopoietic stem cells (HSCs) are the best studied adult stem cells with enormous clinical value. Most of our knowledge about their biology relies on assays at the single HSC level. However, only the recent advances in developing new single cell technologies allowed the elucidation of the complex regulation of HSC fate decision control. This Review will focus on current attempts to investigate individual HSCs at molecular and functional levels. The advantages of these technologies leading to groundbreaking insights into hematopoiesis will be highlighted, and the challenges facing these technologies will be discussed. The importance of combining molecular and functional assays to enlighten regulatory networks of HSC fate decision control, ideally at high temporal resolution, becomes apparent for future studies.
Collapse
Affiliation(s)
- Ilaria Lunger
- Department of Medicine, Hematology/Oncology, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Malak Fawaz
- Department of Medicine, Hematology/Oncology, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Michael A Rieger
- Department of Medicine, Hematology/Oncology, Goethe University Frankfurt, Frankfurt am Main, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany.,German Cancer Research Center (DKFZ), Heidelberg, Germany
| |
Collapse
|
6
|
Damnernsawad A, Kong G, Wen Z, Liu Y, Rajagopalan A, You X, Wang J, Zhou Y, Ranheim EA, Luo HR, Chang Q, Zhang J. Kras is Required for Adult Hematopoiesis. Stem Cells 2016; 34:1859-71. [PMID: 26972179 DOI: 10.1002/stem.2355] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 02/15/2016] [Indexed: 12/21/2022]
Abstract
Previous studies indicate that Kras is dispensable for fetal liver hematopoiesis, but its role in adult hematopoiesis remains unclear. Here, we generated a Kras conditional knockout allele to address this question. Deletion of Kras in adult bone marrow (BM) is mediated by Vav-Cre or inducible Mx1-Cre. We find that loss of Kras leads to greatly reduced thrombopoietin (TPO) signaling in hematopoietic stem cells (HSCs) and multipotent progenitors (MPPs), while stem cell factor-evoked ERK1/2 activation is not affected. The compromised TPO signaling is associated with reduced long term- and intermediate-term HSC compartments and a bias toward myeloid differentiation in MPPs. Although granulocyte macrophage colony-stimulating factor (GM-CSF)-evoked ERK1/2 activation is only moderately decreased in Kras(-/-) myeloid progenitors, it is blunted in neutrophils and neutrophil survival is significantly reduced in vitro. At 9-12 months old, Kras conditional knockout mice develop profound hematopoietic defects, including splenomegaly, an expanded neutrophil compartment, and reduced B cell number. In a serial transplantation assay, the reconstitution potential of Kras(-/-) BM cells is greatly compromised, which is attributable to defects in the self-renewal of Kras(-/-) HSCs and defects in differentiated hematopoietic cells. Our results demonstrate that Kras is a major regulator of TPO and GM-CSF signaling in specific populations of hematopoietic cells and its function is required for adult hematopoiesis. Stem Cells 2016;34:1859-1871.
Collapse
Affiliation(s)
- Alisa Damnernsawad
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Wisconsin, USA
| | - Guangyao Kong
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Wisconsin, USA
| | - Zhi Wen
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Wisconsin, USA
| | - Yangang Liu
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Wisconsin, USA
| | - Adhithi Rajagopalan
- Cellular and Molecular Biology Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Xiaona You
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Wisconsin, USA
| | - Jinyong Wang
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Wisconsin, USA
| | - Yun Zhou
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Wisconsin, USA
| | - Erik A Ranheim
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Hongbo R Luo
- Department of Pathology, Harvard Medical School and Boston Children's Hospital, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Qiang Chang
- Department of Medical Genetics and Department of Neurology, Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jing Zhang
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Wisconsin, USA
| |
Collapse
|
7
|
Wang T, Li C, Xia C, Dong Y, Yang D, Geng Y, Cai J, Zhang J, Zhang X, Wang J. Oncogenic NRAS hyper-activates multiple pathways in human cord blood stem/progenitor cells and promotes myelomonocytic proliferation in vivo. Am J Transl Res 2015; 7:1963-1973. [PMID: 26692939 PMCID: PMC4656772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 10/08/2015] [Indexed: 06/05/2023]
Abstract
Oncogenic NRAS mutations are prevalent in human myeloid leukemia, especially in chronic myelomonocytic leukemia (CMML). NrasG12D mutation at its endogenous locus in murine hematopoietic stem cells (HSCs) leads to CMML and acute T-cell lymphoblastic lymphoma/leukemia in a dose-dependent manner. Hyper-activated MAPK and STAT5 pathways by oncogenic Nras contribute to the leukemogenesis in vivo. However, it is unclear whether these conclusions remain true in a more human relevant model. Here, we evaluated the effects of NRASG12D on human hematopoiesis and leukemogenesis in vitro and in vivo by ectopically expressing NRASG12D in human cord blood stem/progenitor cells (hSPCs). NRASG12D expressing hSPCs preferentially differentiated into myelomonocytic lineage cells, demonstrated by forming more colony forming unit-macrophages than control hSPCs in cultures. Transplantation of NRASG12D expressing hSPCs initiated myeloproliferative neoplasm in immune deficiency mice. All the recipient mice died of myeloid tumor burdens in spleens and bone marrows and none developed lymphoid leukemia. Phospho-flow analysis of CD34(+) CD38(-) hSPCs confirmed that NRASG12D hyper-activated MAPK, AKT and STAT5 pathways. Our study provides the strong evidence that NRASG12D mutation mainly targets monocytic lineage cells and leads to myelomonocytic proliferation in vivo in a highly human relevant context.
Collapse
Affiliation(s)
- Tongjie Wang
- School of Life Sciences, University of Science and Technology of ChinaAnhui, China
- Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineGuangzhou, China
| | - Chen Li
- Department of Hematology, The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhou, China
| | - Chengxiang Xia
- School of Life Sciences, University of Science and Technology of ChinaAnhui, China
- Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineGuangzhou, China
| | - Yong Dong
- Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineGuangzhou, China
| | - Dan Yang
- Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineGuangzhou, China
| | - Yang Geng
- Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineGuangzhou, China
| | - Jizhen Cai
- Laboratory Animal Center, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of SciencesChina
| | - Jing Zhang
- McArdle Laboratory for Cancer Research, University of Wisconsin-MadisonMadison, WI 53706, USA
| | - Xiangzhong Zhang
- Department of Hematology, The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhou, China
| | - Jinyong Wang
- School of Life Sciences, University of Science and Technology of ChinaAnhui, China
- Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative MedicineGuangzhou, China
| |
Collapse
|
8
|
Sands B, Jenkins P, Peria WJ, Naivar M, Houston JP, Brent R. Measuring and sorting cell populations expressing isospectral fluorescent proteins with different fluorescence lifetimes. PLoS One 2014; 9:e109940. [PMID: 25302964 PMCID: PMC4193854 DOI: 10.1371/journal.pone.0109940] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 09/04/2014] [Indexed: 01/03/2023] Open
Abstract
Study of signal transduction in live cells benefits from the ability to visualize and quantify light emitted by fluorescent proteins (XFPs) fused to different signaling proteins. However, because cell signaling proteins are often present in small numbers, and because the XFPs themselves are poor fluorophores, the amount of emitted light, and the observable signal in these studies, is often small. An XFP's fluorescence lifetime contains additional information about the immediate environment of the fluorophore that can augment the information from its weak light signal. Here, we constructed and expressed in Saccharomyces cerevisiae variants of Teal Fluorescent Protein (TFP) and Citrine that were isospectral but had shorter fluorescence lifetimes, ∼1.5 ns vs ∼3 ns. We modified microscopic and flow cytometric instruments to measure fluorescence lifetimes in live cells. We developed digital hardware and a measure of lifetime called a “pseudophasor” that we could compute quickly enough to permit sorting by lifetime in flow. We used these abilities to sort mixtures of cells expressing TFP and the short-lifetime TFP variant into subpopulations that were respectively 97% and 94% pure. This work demonstrates the feasibility of using information about fluorescence lifetime to help quantify cell signaling in living cells at the high throughput provided by flow cytometry. Moreover, it demonstrates the feasibility of isolating and recovering subpopulations of cells with different XFP lifetimes for subsequent experimentation.
Collapse
Affiliation(s)
- Bryan Sands
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Patrick Jenkins
- Department of Chemical Engineering, New Mexico State University, Las Cruces, New Mexico, United States of America
| | - William J. Peria
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Mark Naivar
- Darkling X, LLC, Los Alamos, New Mexico, United States of America
| | - Jessica P. Houston
- Department of Chemical Engineering, New Mexico State University, Las Cruces, New Mexico, United States of America
| | - Roger Brent
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * E-mail:
| |
Collapse
|
9
|
Kong G, Wunderlich M, Yang D, Ranheim EA, Young KH, Wang J, Chang YI, Du J, Liu Y, Tey SR, Zhang X, Juckett M, Mattison R, Damnernsawad A, Zhang J, Mulloy JC, Zhang J. Combined MEK and JAK inhibition abrogates murine myeloproliferative neoplasm. J Clin Invest 2014; 124:2762-73. [PMID: 24812670 DOI: 10.1172/jci74182] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Overactive RAS signaling is prevalent in juvenile myelomonocytic leukemia (JMML) and the myeloproliferative variant of chronic myelomonocytic leukemia (MP-CMML) in humans, and both are refractory to conventional chemotherapy. Conditional activation of a constitutively active oncogenic Nras (NrasG12D/G12D) in murine hematopoietic cells promotes an acute myeloproliferative neoplasm (MPN) that recapitulates many features of JMML and MP-CMML. We found that NrasG12D/G12D-expressing HSCs, which serve as JMML/MP-CMML-initiating cells, show strong hyperactivation of ERK1/2, promoting hyperproliferation and depletion of HSCs and expansion of downstream progenitors. Inhibition of the MEK pathway alone prolonged the presence of NrasG12D/G12D-expressing HSCs but failed to restore their proper function. Consequently, approximately 60% of NrasG12D/G12D mice treated with MEK inhibitor alone died within 20 weeks, and the remaining animals continued to display JMML/MP-CMML-like phenotypes. In contrast, combined inhibition of MEK and JAK/STAT signaling, which is commonly hyperactivated in human and mouse CMML, potently inhibited human and mouse CMML cell growth in vitro, rescued mutant NrasG12D/G12D-expressing HSC function in vivo, and promoted long-term survival without evident disease manifestation in NrasG12D/G12D animals. These results provide a strong rationale for further exploration of combined targeting of MEK/ERK and JAK/STAT in treating patients with JMML and MP-CMML.
Collapse
MESH Headings
- Animals
- Cell Proliferation/drug effects
- Genes, ras
- Humans
- Janus Kinases/antagonists & inhibitors
- Leukemia, Myelomonocytic, Chronic/drug therapy
- Leukemia, Myelomonocytic, Chronic/enzymology
- Leukemia, Myelomonocytic, Chronic/genetics
- Leukemia, Myelomonocytic, Juvenile/drug therapy
- Leukemia, Myelomonocytic, Juvenile/enzymology
- Leukemia, Myelomonocytic, Juvenile/genetics
- MAP Kinase Signaling System/drug effects
- Mice
- Mice, Mutant Strains
- Mitogen-Activated Protein Kinase Kinases/antagonists & inhibitors
- Myeloproliferative Disorders/drug therapy
- Myeloproliferative Disorders/enzymology
- Myeloproliferative Disorders/pathology
- Protein Kinase Inhibitors/administration & dosage
- Signal Transduction/drug effects
Collapse
|
10
|
Thrombopoietin promotes NHEJ DNA repair in hematopoietic stem cells through specific activation of Erk and NF-κB pathways and their target, IEX-1. Blood 2013; 123:509-19. [PMID: 24184684 DOI: 10.1182/blood-2013-07-515874] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Loss of hematopoietic stem cell (HSC) function and increased risk of developing hematopoietic malignancies are severe and concerning complications of anticancer radiotherapy and chemotherapy. We have previously shown that thrombopoietin (TPO), a critical HSC regulator, ensures HSC chromosomal integrity and function in response to γ-irradiation by regulating their DNA-damage response. TPO directly affects the double-strand break (DSB) repair machinery through increased DNA-protein kinase (DNA-PK) phosphorylation and nonhomologous end-joining (NHEJ) repair efficiency and fidelity. This effect is not shared by other HSC growth factors, suggesting that TPO triggers a specific signal in HSCs facilitating DNA-PK activation upon DNA damage. The discovery of these unique signaling pathways will provide a means of enhancing TPO-desirable effects on HSCs and improving the safety of anticancer DNA agents. We show here that TPO specifically triggers Erk and nuclear factor κB (NF-κB) pathways in mouse hematopoietic stem and progenitor cells (HSPCs). Both of these pathways are required for a TPO-mediated increase in DSB repair. They cooperate to induce and activate the early stress-response gene, Iex-1 (ier3), upon DNA damage. Iex-1 forms a complex with pERK and the catalytic subunit of DNA-PK, which is necessary and sufficient to promote TPO-increased DNA-PK activation and NHEJ DSB repair in both mouse and human HSPCs.
Collapse
|
11
|
Nras(G12D/+) promotes leukemogenesis by aberrantly regulating hematopoietic stem cell functions. Blood 2013; 121:5203-7. [PMID: 23687087 DOI: 10.1182/blood-2012-12-475863] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Oncogenic NRAS mutations are frequently identified in human myeloid leukemias. In mice, expression of endogenous oncogenic Nras (Nras(G12D/+)) in hematopoietic cells leads to expansion of myeloid progenitors, increased long-term reconstitution of bone marrow cells, and a chronic myeloproliferative neoplasm (MPN). However, acute expression of Nras(G12D/+) in a pure C57BL/6 background does not induce hyperactivated granulocyte macrophage colony-stimulating factor signaling or increased proliferation in myeloid progenitors. It is thus unclear how Nras(G12D/+) signaling promotes leukemogenesis. Here, we show that hematopoietic stem cells (HSCs) expressing Nras(G12D/+) serve as MPN-initiating cells. They undergo moderate hyperproliferation with increased self-renewal. The aberrant Nras(G12D/+) HSC function is associated with hyperactivation of ERK1/2 in HSCs. Conversely, downregulation of MEK/ERK by pharmacologic and genetic approaches attenuates the cycling of Nras(G12D/+) HSCs and prevents the expansion of Nras(G12D/+) HSCs and myeloid progenitors. Our data delineate critical mechanisms of oncogenic Nras signaling in HSC function and leukemogenesis.
Collapse
|