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Heiblig M, Patel B, Jamilloux Y. VEXAS syndrome, a new kid on the block of auto-inflammatory diseases: A hematologist's point of view. Best Pract Res Clin Rheumatol 2023; 37:101861. [PMID: 37652853 DOI: 10.1016/j.berh.2023.101861] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/29/2023] [Accepted: 07/24/2023] [Indexed: 09/02/2023]
Abstract
The recently discovered VEXAS syndrome is caused by the clonal expansion of hematopoietic stem or progenitor cells with acquired mutations in UBA1 gene, which encodes for a key enzyme of the ubiquitylation proteasome system. As a result, a shorter cytoplasmic isoform of UBA1 is transcribed, which is non-functional. The disease is characterized by non-specific and highly heterogeneous inflammatory manifestations and macrocytic anemia. VEXAS syndrome is a unique acquired hematological monogenic disease with unexpected association with hematological neoplasms. Despite its hematopoetic origin, patients with VEXAS syndrome usually present with multi-systemicinflammatory disease and are treated by physicians from many different specialties (rheumatologists, dermatologists, hematologistis, etc.). Furthermore, manifestations of VEXAS may fulfill criteria for existing diseases: relapsing polychondritis, giant cell arteritis, polyarteritis nodosa, and myelodysplastic syndrome. The goal of this review is to depict VEXAS syndrome from a hematologic point of view regarding its consequences on hematopoiesis and the current strategies on therapeutic interventions.
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Affiliation(s)
- Maël Heiblig
- Hospices Civils de Lyon, Hôpital Lyon Sud, Service d'hématologie clinique, Lyon, France; Université Claude Bernard Lyon 1, Faculté de médecine et de maïeutique Lyon Sud Charles Mérieux, Lymphoma Immunobiology Team, Pierre Bénite, France.
| | - Bhavisha Patel
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Yvan Jamilloux
- Hospices Civils de Lyon, Hôpital de la Croix Rousse, Service de médecine interne, Lyon, France
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2
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The diverse repertoire of ISG15: more intricate than initially thought. Exp Mol Med 2022; 54:1779-1792. [PMID: 36319753 PMCID: PMC9722776 DOI: 10.1038/s12276-022-00872-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 08/03/2022] [Accepted: 08/08/2022] [Indexed: 11/05/2022] Open
Abstract
ISG15, the product of interferon (IFN)-stimulated gene 15, is the first identified ubiquitin-like protein (UBL), which plays multifaceted roles not only as a free intracellular or extracellular molecule but also as a post-translational modifier in the process of ISG15 conjugation (ISGylation). ISG15 has only been identified in vertebrates, indicating that the functions of ISG15 and its conjugation are restricted to higher eukaryotes and have evolved with IFN signaling. Despite the highlighted complexity of ISG15 and ISGylation, it has been suggested that ISG15 and ISGylation profoundly impact a variety of cellular processes, including protein translation, autophagy, exosome secretion, cytokine secretion, cytoskeleton dynamics, DNA damage response, telomere shortening, and immune modulation, which emphasizes the necessity of reassessing ISG15 and ISGylation. However, the underlying mechanisms and molecular consequences of ISG15 and ISGylation remain poorly defined, largely due to a lack of knowledge on the ISG15 target repertoire. In this review, we provide a comprehensive overview of the mechanistic understanding and molecular consequences of ISG15 and ISGylation. We also highlight new insights into the roles of ISG15 and ISGylation not only in physiology but also in the pathogenesis of various human diseases, especially in cancer, which could contribute to therapeutic intervention in human diseases.
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3
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More than Meets the ISG15: Emerging Roles in the DNA Damage Response and Beyond. Biomolecules 2020; 10:biom10111557. [PMID: 33203188 PMCID: PMC7698331 DOI: 10.3390/biom10111557] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 12/13/2022] Open
Abstract
Maintenance of genome stability is a crucial priority for any organism. To meet this priority, robust signalling networks exist to facilitate error-free DNA replication and repair. These signalling cascades are subject to various regulatory post-translational modifications that range from simple additions of chemical moieties to the conjugation of ubiquitin-like proteins (UBLs). Interferon Stimulated Gene 15 (ISG15) is one such UBL. While classically thought of as a component of antiviral immunity, ISG15 has recently emerged as a regulator of genome stability, with key roles in the DNA damage response (DDR) to modulate p53 signalling and error-free DNA replication. Additional proteomic analyses and cancer-focused studies hint at wider-reaching, uncharacterised functions for ISG15 in genome stability. We review these recent discoveries and highlight future perspectives to increase our understanding of this multifaceted UBL in health and disease.
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4
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Wu SF, Xia L, Shi XD, Dai YJ, Zhang WN, Zhao JM, Zhang W, Weng XQ, Lu J, Le HY, Tao SC, Zhu J, Chen Z, Wang YY, Chen S. RIG-I regulates myeloid differentiation by promoting TRIM25-mediated ISGylation. Proc Natl Acad Sci U S A 2020; 117:14395-14404. [PMID: 32513696 PMCID: PMC7322067 DOI: 10.1073/pnas.1918596117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Retinoic acid-inducible gene I (RIG-I) is up-regulated during granulocytic differentiation of acute promyelocytic leukemia (APL) cells induced by all-trans retinoic acid (ATRA). It has been reported that RIG-I recognizes virus-specific 5'-ppp-double-stranded RNA (dsRNA) and activates the type I interferons signaling pathways in innate immunity. However, the functions of RIG-I in hematopoiesis remain unclear, especially regarding its possible interaction with endogenous RNAs and the associated pathways that could contribute to the cellular differentiation and maturation. Herein, we identified a number of RIG-I-binding endogenous RNAs in APL cells following ATRA treatment, including the tripartite motif-containing protein 25 (TRIM25) messenger RNA (mRNA). TRIM25 encodes the protein known as an E3 ligase for ubiquitin/interferon (IFN)-induced 15-kDa protein (ISG15) that is involved in RIG-I-mediated antiviral signaling. We show that RIG-I could bind TRIM25 mRNA via its helicase domain and C-terminal regulatory domain, enhancing the stability of TRIM25 transcripts. RIG-I could increase the transcriptional expression of TRIM25 by caspase recruitment domain (CARD) domain through an IFN-stimulated response element. In addition, RIG-I activated other key genes in the ISGylation pathway by activating signal transducer and activator of transcription 1 (STAT1), including the modifier ISG15 and several enzymes responsible for the conjugation of ISG15 to protein substrates. RIG-I cooperated with STAT1/2 and interferon regulatory factor 1 (IRF1) to promote the activation of the ISGylation pathway. The integrity of ISGylation in ATRA or RIG-I-induced cell differentiation was essential given that knockdown of TRIM25 or ISG15 resulted in significant inhibition of this process. Our results provide insight into the role of the RIG-I-TRIM25-ISGylation axis in myeloid differentiation.
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Affiliation(s)
- Song-Fang Wu
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Li Xia
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiao-Dong Shi
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yu-Jun Dai
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wei-Na Zhang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jun-Mei Zhao
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Wu Zhang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xiang-Qin Weng
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jing Lu
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Huang-Ying Le
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Sheng-Ce Tao
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jiang Zhu
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Zhu Chen
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China;
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yue-Ying Wang
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China;
| | - Saijuan Chen
- State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, National Research Center for Translational Medicine at Shanghai, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China;
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China
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Teplyakov E, Wu Q, Liu J, Pugacheva EM, Loukinov D, Boukaba A, Lobanenkov V, Strunnikov A. The downregulation of putative anticancer target BORIS/CTCFL in an addicted myeloid cancer cell line modulates the expression of multiple protein coding and ncRNA genes. Oncotarget 2017; 8:73448-73468. [PMID: 29088719 PMCID: PMC5650274 DOI: 10.18632/oncotarget.20627] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 08/23/2017] [Indexed: 12/27/2022] Open
Abstract
The BORIS/CTCFL gene, is a testis-specific CTCF paralog frequently erroneously activated in cancer, although its exact role in cancer remains unclear. BORIS is both a transcription factor and an architectural chromatin protein. BORIS' normal role is to establish a germline-like gene expression and remodel the epigenetic landscape in testis; it similarly remodels chromatin when activated in human cancer. Critically, at least one cancer cell line, K562, is dependent on BORIS for its self-renewal and survival. Here, we downregulate BORIS expression in the K562 cancer cell line to investigate downstream pathways regulated by BORIS. RNA-seq analyses of both mRNA and small ncRNAs, including miRNA and piRNA, in the knock-down cells revealed a set of differentially expressed genes and pathways, including both testis-specific and general proliferation factors, as well as proteins involved in transcription regulation and cell physiology. The differentially expressed genes included important transcriptional regulators such as SOX6 and LIN28A. Data indicate that both direct binding of BORIS to promoter regions and locus-control activity via long-distance chromatin domain regulation are involved. The sum of findings suggests that BORIS activation in leukemia does not just recapitulate the germline, but creates a unique regulatory network.
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Affiliation(s)
- Evgeny Teplyakov
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, China.,The University of the Chinese Academy of Sciences, Beijing, China
| | - Qiongfang Wu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, China
| | - Jian Liu
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, China
| | | | - Dmitry Loukinov
- NIH, NIAID, Laboratory of Immunogenetics, Rockville, MD, USA
| | - Abdelhalim Boukaba
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, China
| | | | - Alexander Strunnikov
- Molecular Epigenetics Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, China.,The University of the Chinese Academy of Sciences, Beijing, China
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6
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Komeno Y, Huang YJ, Qiu J, Lin L, Xu Y, Zhou Y, Chen L, Monterroza DD, Li H, DeKelver RC, Yan M, Fu XD, Zhang DE. SRSF2 Is Essential for Hematopoiesis, and Its Myelodysplastic Syndrome-Related Mutations Dysregulate Alternative Pre-mRNA Splicing. Mol Cell Biol 2015; 35:3071-82. [PMID: 26124281 PMCID: PMC4525309 DOI: 10.1128/mcb.00202-15] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 03/19/2015] [Accepted: 06/19/2015] [Indexed: 01/06/2023] Open
Abstract
Myelodysplastic syndromes (MDS) are a group of neoplasms characterized by ineffective myeloid hematopoiesis and various risks for leukemia. SRSF2, a member of the serine/arginine-rich (SR) family of splicing factors, is one of the mutation targets associated with poor survival in patients suffering from myelodysplastic syndromes. Here we report the biological function of SRSF2 in hematopoiesis by using conditional knockout mouse models. Ablation of SRSF2 in the hematopoietic lineage caused embryonic lethality, and Srsf2-deficient fetal liver cells showed significantly enhanced apoptosis and decreased levels of hematopoietic stem/progenitor cells. Induced ablation of SRSF2 in adult Mx1-Cre Srsf2(flox/flox) mice upon poly(I):poly(C) injection demonstrated a significant decrease in lineage(-) Sca(+) c-Kit(+) cells in bone marrow. To reveal the functional impact of myelodysplastic syndromes-associated mutations in SRSF2, we analyzed splicing responses on the MSD-L cell line and found that the missense mutation of proline 95 to histidine (P95H) and a P95-to-R102 in-frame 8-amino-acid deletion caused significant changes in alternative splicing. The affected genes were enriched in cancer development and apoptosis. These findings suggest that intact SRSF2 is essential for the functional integrity of the hematopoietic system and that its mutations likely contribute to development of myelodysplastic syndromes.
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Affiliation(s)
- Yukiko Komeno
- Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California, USA
| | - Yi-Jou Huang
- Division of Biological Sciences, University of California, San Diego, La Jolla, California, USA
| | - Jinsong Qiu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA
| | - Leo Lin
- Division of Biological Sciences, University of California, San Diego, La Jolla, California, USA
| | - YiJun Xu
- Division of Biological Sciences, University of California, San Diego, La Jolla, California, USA
| | - Yu Zhou
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA
| | - Liang Chen
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA
| | - Dora D Monterroza
- Division of Biological Sciences, University of California, San Diego, La Jolla, California, USA
| | - Hairi Li
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA
| | - Russell C DeKelver
- Division of Biological Sciences, University of California, San Diego, La Jolla, California, USA
| | - Ming Yan
- Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California, USA
| | - Xiang-Dong Fu
- Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California, USA Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California, USA
| | - Dong-Er Zhang
- Moores UCSD Cancer Center, University of California, San Diego, La Jolla, California, USA Division of Biological Sciences, University of California, San Diego, La Jolla, California, USA Department of Pathology, University of California, San Diego, La Jolla, California, USA
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7
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Mechanism of Dose-Dependent Regulation of UBE1L by Polyphenols in Human Bronchial Epithelial Cells. J Cell Biochem 2015; 116:1553-62. [DOI: 10.1002/jcb.25109] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 01/23/2015] [Indexed: 11/07/2022]
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8
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Glass C, Wuertzer C, Cui X, Bi Y, Davuluri R, Xiao YY, Wilson M, Owens K, Zhang Y, Perkins A. Global Identification of EVI1 Target Genes in Acute Myeloid Leukemia. PLoS One 2013; 8:e67134. [PMID: 23826213 PMCID: PMC3694976 DOI: 10.1371/journal.pone.0067134] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 05/19/2013] [Indexed: 12/20/2022] Open
Abstract
The ecotropic virus integration site 1 (EVI1) transcription factor is associated with human myeloid malignancy of poor prognosis and is overexpressed in 8-10% of adult AML and strikingly up to 27% of pediatric MLL-rearranged leukemias. For the first time, we report comprehensive genomewide EVI1 binding and whole transcriptome gene deregulation in leukemic cells using a combination of ChIP-Seq and RNA-Seq expression profiling. We found disruption of terminal myeloid differentiation and cell cycle regulation to be prominent in EVI-induced leukemogenesis. Specifically, we identified EVI1 directly binds to and downregulates the master myeloid differentiation gene Cebpe and several of its downstream gene targets critical for terminal myeloid differentiation. We also found EVI1 binds to and downregulates Serpinb2 as well as numerous genes involved in the Jak-Stat signaling pathway. Finally, we identified decreased expression of several ATP-dependent P2X purinoreceptors genes involved in apoptosis mechanisms. These findings provide a foundation for future study of potential therapeutic gene targets for EVI1-induced leukemia.
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Affiliation(s)
- Carolyn Glass
- Department of Pathology and Lab Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Charles Wuertzer
- Department of Pathology and Lab Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Xiaohui Cui
- Department of Pathology and Lab Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Yingtao Bi
- Molecular and Cellular Oncogenesis Program, Center for Systems and Computational Biology The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Ramana Davuluri
- Molecular and Cellular Oncogenesis Program, Center for Systems and Computational Biology The Wistar Institute, Philadelphia, Pennsylvania, United States of America
| | - Ying-Yi Xiao
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Michael Wilson
- Department of Pathology and Lab Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Kristina Owens
- Department of Pathology and Lab Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Yi Zhang
- Department of Pathology and Lab Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Archibald Perkins
- Department of Pathology and Lab Medicine, University of Rochester Medical Center, Rochester, New York, United States of America
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Cong XL, Lo MC, Reuter BA, Yan M, Fan JB, Zhang DE. Usp18 promotes conventional CD11b+ dendritic cell development. THE JOURNAL OF IMMUNOLOGY 2012; 188:4776-81. [PMID: 22491252 DOI: 10.4049/jimmunol.1101609] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Dendritic cells (DCs) represent the key cells linking innate and adaptive immune responses. It is critical to understand the molecular factors regulating DC differentiation. Usp18 is an IFN-inducible member of the ubiquitin-specific protease family, which deconjugates ubiquitin-like modifier ISG15 from target proteins and competitively inhibits IFN-α/β-induced JAK/STAT activation. This study demonstrates that the frequency of conventional CD11b(+) DCs in the spleen of Usp18(-/-) mice was significantly reduced, whereas the frequencies of conventional CD8(+) DCs and plasmacytoid DCs remained normal. In addition, Usp18(-/-) bone marrow (BM) cells generate DCs less efficiently in GM-CSF-supplemented culture, demonstrating a fundamental defect throughout the DC differentiation pathway. Usp18(-/-) BM cells were rescued by exogenous expression of either wild-type or deconjugation-inactive Usp18, and superimposition of an IFN-α/β receptor knockout returned in vivo DC populations to normal, clearly showing that the defect seen is due solely to Usp18's effect on IFN signaling. Finally, Usp18(-/-) BM-derived DCs expressed high levels of SOCS1/SOCS3, known inhibitors of GM-CSF signaling, providing a mechanistic explanation for the phenotype. In conclusion, we have identified a novel role of Usp18 in modulating conventional CD11b(+) DC development via its inhibitory effect on type I IFN signaling.
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Affiliation(s)
- Xiu-Li Cong
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, USA
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10
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Erg is required for self-renewal of hematopoietic stem cells during stress hematopoiesis in mice. Blood 2011; 118:2454-61. [PMID: 21673349 DOI: 10.1182/blood-2011-03-344739] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Hematopoietic stem cells (HSCs) are rare residents of the bone marrow responsible for the lifelong production of blood cells. Regulation of the balance between HSC self-renewal and differentiation is central to hematopoiesis, allowing precisely regulated generation of mature blood cells at steady state and expanded production at times of rapid need, as well as maintaining ongoing stem cell capacity. Erg, a member of the Ets family of transcription factors, is deregulated in cancers; and although Erg is known to be required for regulation of adult HSCs, its precise role has not been defined. We show here that, although heterozygosity for functional Erg is sufficient for adequate steady-state HSC maintenance, Erg(+/Mld2) mutant mice exhibit impaired HSC self-renewal after bone marrow transplantation or during recovery from myelotoxic stress. Moreover, although mice functionally compromised for either Erg or Mpl, the receptor for thrombopoietin, a key regulator of HSC quiescence, maintained sufficient HSC activity to sustain hematopoiesis, Mpl(-/-) Erg(+/Mld2) compound mutant mice displayed exacerbated stem cell deficiencies and bone marrow failure. Thus, Erg is a critical regulator of adult HSCs, essential for maintaining self-renewal at times of high HSC cycling.
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11
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Zhang D, Zhang DE. Interferon-stimulated gene 15 and the protein ISGylation system. J Interferon Cytokine Res 2010; 31:119-30. [PMID: 21190487 DOI: 10.1089/jir.2010.0110] [Citation(s) in RCA: 245] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Interferon-stimulated gene 15 (ISG15) is one of the most upregulated genes upon Type I interferon treatment or pathogen infection. Its 17 kDa protein product, ISG15, was the first ubiquitin-like modifier identified, and is similar to a ubiquitin linear dimer. As ISG15 modifies proteins in a similar manner to ubiquitylation, protein conjugation by ISG15 is termed ISGylation. Some of the primary enzymes that promote ISGylation are also involved in ubiquitin conjugation. The process to remove ISG15 from its conjugated proteins, termed de-ISGylation, is performed by a cellular ISG15-specific protease, ubiquitin-specific proteases with molecular mass 43 kDa (UBP43)/ubiquitin-specific proteases 18. Relative to ubiquitin, the biological function of ISG15 is still poorly understood, but ISG15 appears to play important roles in various biological and cellular functions. Therefore, there is growing interest in ISG15, as the study of free ISG15 and functional consequences of ISGylation/de-ISGylation may identify useful therapeutic targets. This review highlights recent discoveries and remaining questions important to understanding the biological functions of ISG15.
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Affiliation(s)
- Dongxian Zhang
- Sanford-Burnham Medical Research Institute, La Jolla, California, USA
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