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Morodomi Y, Kanaji S, Sullivan BM, Zarpellon A, Orje JN, Won E, Shapiro R, Yang XL, Ruf W, Schimmel P, Ruggeri ZM, Kanaji T. Inflammatory platelet production stimulated by tyrosyl-tRNA synthetase mimicking viral infection. Proc Natl Acad Sci U S A 2022; 119:e2212659119. [PMID: 36409883 PMCID: PMC9860251 DOI: 10.1073/pnas.2212659119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/20/2022] [Indexed: 11/22/2022] Open
Abstract
Platelets play a role not only in hemostasis and thrombosis, but also in inflammation and innate immunity. We previously reported that an activated form of tyrosyl-tRNA synthetase (YRSACT) has an extratranslational activity that enhances megakaryopoiesis and platelet production in mice. Here, we report that YRSACT mimics inflammatory stress inducing a unique megakaryocyte (MK) population with stem cell (Sca1) and myeloid (F4/80) markers through a mechanism dependent on Toll-like receptor (TLR) activation and type I interferon (IFN-I) signaling. This mimicry of inflammatory stress by YRSACT was studied in mice infected by lymphocytic choriomeningitis virus (LCMV). Using Sca1/EGFP transgenic mice, we demonstrated that IFN-I induced by YRSACT or LCMV infection suppressed normal hematopoiesis while activating an alternative pathway of thrombopoiesis. Platelets of inflammatory origin (Sca1/EGFP+) were a relevant proportion of those circulating during recovery from thrombocytopenia. Analysis of these "inflammatory" MKs and platelets suggested their origin in myeloid/MK-biased hematopoietic stem cells (HSCs) that bypassed the classical MK-erythroid progenitor (MEP) pathway to replenish platelets and promote recovery from thrombocytopenia. Notably, inflammatory platelets displayed enhanced agonist-induced activation and procoagulant activities. Moreover, myeloid/MK-biased progenitors and MKs were mobilized from the bone marrow, as evidenced by their presence in the lung microvasculature within fibrin-containing microthrombi. Our results define the function of YRSACT in platelet generation and contribute to elucidate platelet alterations in number and function during viral infection.
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Affiliation(s)
- Yosuke Morodomi
- Department of Molecular Medicine, MERU-Roon Research Center on Vascular Biology, The Scripps Research Institute, La Jolla, CA92037
- The Scripps Laboratories for tRNA Synthetase Research, Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA92037
| | - Sachiko Kanaji
- Department of Molecular Medicine, MERU-Roon Research Center on Vascular Biology, The Scripps Research Institute, La Jolla, CA92037
- The Scripps Laboratories for tRNA Synthetase Research, Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA92037
| | - Brian M. Sullivan
- Viral-Immunobiology Laboratory, Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA92037
| | | | - Jennifer N. Orje
- Department of Molecular Medicine, MERU-Roon Research Center on Vascular Biology, The Scripps Research Institute, La Jolla, CA92037
- MERU-VasImmune, Inc., San Diego, CA92121
| | - Eric Won
- Department of Molecular Medicine, MERU-Roon Research Center on Vascular Biology, The Scripps Research Institute, La Jolla, CA92037
- Department of Hematology and Oncology, University of California, San Diego, CA92093
- Rady Children’s Hospital, San Diego, CA92123
| | - Ryan Shapiro
- The Scripps Laboratories for tRNA Synthetase Research, Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA92037
| | - Xiang-Lei Yang
- The Scripps Laboratories for tRNA Synthetase Research, Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA92037
| | - Wolfram Ruf
- Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg University, 55128Germany
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA92037
| | - Paul Schimmel
- The Scripps Laboratories for tRNA Synthetase Research, Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA92037
| | - Zaverio M. Ruggeri
- Department of Molecular Medicine, MERU-Roon Research Center on Vascular Biology, The Scripps Research Institute, La Jolla, CA92037
- MERU-VasImmune, Inc., San Diego, CA92121
| | - Taisuke Kanaji
- Department of Molecular Medicine, MERU-Roon Research Center on Vascular Biology, The Scripps Research Institute, La Jolla, CA92037
- The Scripps Laboratories for tRNA Synthetase Research, Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA92037
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Baymiller M, Nordick B, Forsyth CM, Martinis SA. Tissue-specific alternative splicing separates the catalytic and cell signaling functions of human leucyl-tRNA synthetase. J Biol Chem 2022; 298:101757. [PMID: 35202654 PMCID: PMC8941210 DOI: 10.1016/j.jbc.2022.101757] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 02/11/2022] [Accepted: 02/12/2022] [Indexed: 11/29/2022] Open
Abstract
The aminoacyl-tRNA synthetases are an ancient and ubiquitous component of all life. Many eukaryotic synthetases balance their essential function, preparing aminoacyl-tRNA for use in mRNA translation, with diverse roles in cell signaling. Herein, we use long-read sequencing to discover a leukocyte-specific exon skipping event in human leucyl-tRNA synthetase (LARS). We show that this highly expressed splice variant, LSV3, is regulated by serine-arginine-rich splicing factor 1 (SRSF1) in a cell-type-specific manner. LSV3 has a 71 amino acid deletion in the catalytic domain and lacks any tRNA leucylation activity in vitro. However, we demonstrate that this LARS splice variant retains its role as a leucine sensor and signal transducer for the proliferation-promoting mTOR kinase. This is despite the exon deletion in LSV3 including a portion of the previously mapped Vps34-binding domain used for one of two distinct pathways from LARS to mTOR. In conclusion, alternative splicing of LARS has separated the ancient catalytic activity of this housekeeping enzyme from its more recent evolutionary role in cell signaling, providing an opportunity for functional specificity in human immune cells.
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Affiliation(s)
- Max Baymiller
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Benjamin Nordick
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Connor M Forsyth
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Susan A Martinis
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
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Preger C, Wigren E, Ossipova E, Marks C, Lengqvist J, Hofström C, Andersson O, Jakobsson PJ, Gräslund S, Persson H. Generation and validation of recombinant antibodies to study human aminoacyl-tRNA synthetases. J Biol Chem 2020; 295:13981-13993. [PMID: 32817337 DOI: 10.1074/jbc.ra120.012893] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 08/10/2020] [Indexed: 11/06/2022] Open
Abstract
Aminoacyl-tRNA synthetases (aaRSs) have long been viewed as mere housekeeping proteins and have therefore often been overlooked in drug discovery. However, recent findings have revealed that many aaRSs have noncanonical functions, and several of the aaRSs have been linked to autoimmune diseases, cancer, and neurological disorders. Deciphering these roles has been challenging because of a lack of tools to enable their study. To help solve this problem, we have generated recombinant high-affinity antibodies for a collection of thirteen cytoplasmic and one mitochondrial aaRSs. Selected domains of these proteins were produced recombinantly in Escherichia coli and used as antigens in phage display selections using a synthetic human single-chain fragment variable library. All targets yielded large sets of antibody candidates that were validated through a panel of binding assays against the purified antigen. Furthermore, the top-performing binders were tested in immunoprecipitation followed by MS for their ability to capture the endogenous protein from mammalian cell lysates. For antibodies targeting individual members of the multi-tRNA synthetase complex, we were able to detect all members of the complex, co-immunoprecipitating with the target, in several cell types. The functionality of a subset of binders for each target was also confirmed using immunofluorescence. The sequences of these proteins have been deposited in publicly available databases and repositories. We anticipate that this open source resource, in the form of high-quality recombinant proteins and antibodies, will accelerate and empower future research of the role of aaRSs in health and disease.
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Affiliation(s)
- Charlotta Preger
- Structural Genomics Consortium, Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Edvard Wigren
- Structural Genomics Consortium, Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Elena Ossipova
- Structural Genomics Consortium, Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Carolyn Marks
- Structural Genomics Consortium, Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | | | - Camilla Hofström
- Science for Life Laboratory, Drug Discovery and Development, Stockholm, Sweden.,School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, Stockholm, Sweden
| | - Oskar Andersson
- Science for Life Laboratory, Drug Discovery and Development, Stockholm, Sweden.,School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, Stockholm, Sweden
| | - Per-Johan Jakobsson
- Structural Genomics Consortium, Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Susanne Gräslund
- Structural Genomics Consortium, Division of Rheumatology, Department of Medicine Solna, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Helena Persson
- Science for Life Laboratory, Drug Discovery and Development, Stockholm, Sweden .,School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, Stockholm, Sweden
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Wakasugi K, Yokosawa T. Non-canonical functions of human cytoplasmic tyrosyl-, tryptophanyl- and other aminoacyl-tRNA synthetases. Enzymes 2020; 48:207-242. [PMID: 33837705 DOI: 10.1016/bs.enz.2020.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Aminoacyl-tRNA synthetases catalyze the aminoacylation of their cognate tRNAs. Here we review the accumulated knowledge of non-canonical functions of human cytoplasmic aminoacyl-tRNA synthetases, especially tyrosyl- (TyrRS) and tryptophanyl-tRNA synthetase (TrpRS). Human TyrRS and TrpRS have an extra domain. Two distinct cytokines, i.e., the core catalytic "mini TyrRS" and the extra C-domain, are generated from human TyrRS by proteolytic cleavage. Moreover, the core catalytic domains of human TyrRS and TrpRS function as angiogenic and angiostatic factors, respectively, whereas the full-length forms are inactive for this function. It is also known that many synthetases change their localization in response to a specific signal and subsequently exhibit alternative functions. Furthermore, some synthetases function as sensors for amino acids by changing their protein interactions in an amino acid-dependent manner. Further studies will be necessary to elucidate regulatory mechanisms of non-canonical functions of aminoacyl-tRNA synthetases in particular, by analyzing the effect of their post-translational modifications.
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Affiliation(s)
- Keisuke Wakasugi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan; Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | - Takumi Yokosawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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Jin M. Unique roles of tryptophanyl-tRNA synthetase in immune control and its therapeutic implications. Exp Mol Med 2019; 51:1-10. [PMID: 30613102 PMCID: PMC6321835 DOI: 10.1038/s12276-018-0196-9] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 08/15/2018] [Accepted: 08/27/2018] [Indexed: 12/11/2022] Open
Abstract
Tryptophanyl tRNA synthetase (WRS) is an essential enzyme as it catalyzes the ligation of tryptophan to its cognate tRNA during translation. Interestingly, mammalian WRS has evolved to acquire domains or motifs for novel functions beyond protein synthesis; WRS can also further expand its functions via alternative splicing and proteolytic cleavage. WRS is localized not only to the nucleus but also to the extracellular space, playing a key role in innate immunity, angiogenesis, and IFN-γ signaling. In addition, the expression of WRS varies significantly in different tissues and pathological states, implying that it plays unique roles in physiological homeostasis and immune defense. This review addresses the current knowledge regarding the evolution, structural features, and context-dependent functions of WRS, particularly focusing on its roles in immune regulation. Targeting tryptophanyl tRNA synthetase (WRS), an evolutionarily conserved enzyme involved in protein synthesis, could be an effective strategy for modulating the immune system. In addition to helping translate mRNA into amino acid sequences in cytoplasm, human WRS can be secreted and activate immune responses against invading pathogens. Mirim Jin at Gachon University, Incheon, South Korea, reviews recent studies on the structure, expression pattern and functions of WRS other than protein synthesis. High levels of WRS protein have been found in patients with sepsis and autoimmune diseases suggesting that inhibiting WRS could be a potential therapeutic approach for treating these conditions. Further research into WRS will shed light not only on how it regulates the immune system, but also on how it exerts other reported effects on blood vessel formation and cell migration.
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Affiliation(s)
- Mirim Jin
- Department of Microbiology, College of Medicine, Gachon University, Incheon, Korea. .,Department of Health Science and Technology, GAIHST, Gachon University, Incheon, Korea.
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Debard S, Bader G, De Craene JO, Enkler L, Bär S, Laporte D, Hammann P, Myslinski E, Senger B, Friant S, Becker HD. Nonconventional localizations of cytosolic aminoacyl-tRNA synthetases in yeast and human cells. Methods 2017; 113:91-104. [DOI: 10.1016/j.ymeth.2016.09.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 09/27/2016] [Accepted: 09/30/2016] [Indexed: 11/26/2022] Open
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