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Prakash P, Khodke P, Balasubramaniam M, Davids BO, Hollis T, Davis J, Kumbhar B, Dash C. Three prime repair exonuclease 1 preferentially degrades the integration-incompetent HIV-1 DNA through favorable kinetics, thermodynamic, structural, and conformational properties. J Biol Chem 2024; 300:107438. [PMID: 38838778 DOI: 10.1016/j.jbc.2024.107438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 05/17/2024] [Accepted: 05/24/2024] [Indexed: 06/07/2024] Open
Abstract
HIV-1 integration into the human genome is dependent on 3'-processing of the viral DNA. Recently, we reported that the cellular Three Prime Repair Exonuclease 1 (TREX1) enhances HIV-1 integration by degrading the unprocessed viral DNA, while the integration-competent 3'-processed DNA remained resistant. Here, we describe the mechanism by which the 3'-processed HIV-1 DNA resists TREX1-mediated degradation. Our kinetic studies revealed that the rate of cleavage (kcat) of the 3'-processed DNA was significantly lower (approximately 2-2.5-fold) than the unprocessed HIV-1 DNA by TREX1. The kcat values of human TREX1 for the processed U5 and U3 DNA substrates were 3.8 s-1 and 4.5 s-1, respectively. In contrast, the unprocessed U5 and U3 substrates were cleaved at 10.2 s-1 and 9.8 s-1, respectively. The efficiency of degradation (kcat/Km) of the 3'-processed DNA (U5-70.2 and U3-28.05 pM-1s-1) was also significantly lower than the unprocessed DNA (U5-103.1 and U3-65.3 pM-1s-1). Furthermore, the binding affinity (Kd) of TREX1 was markedly lower (∼2-fold) for the 3'-processed DNA than the unprocessed DNA. Molecular docking and dynamics studies revealed distinct conformational binding modes of TREX1 with the 3'-processed and unprocessed HIV-1 DNA. Particularly, the unprocessed DNA was favorably positioned in the active site with polar interactions with the catalytic residues of TREX1. Additionally, a stable complex was formed between TREX1 and the unprocessed DNA compared the 3'-processed DNA. These results pinpoint the mechanism by which TREX1 preferentially degrades the integration-incompetent HIV-1 DNA and reveal the unique structural and conformational properties of the integration-competent 3'-processed HIV-1 DNA.
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Affiliation(s)
- Prem Prakash
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, Tennessee, USA
| | - Purva Khodke
- Department of Biological Sciences, Sunandan Divatia School of Science, SVKM's NMIMS (Deemed-to-be-) University, Mumbai, Maharashtra, India
| | - Muthukumar Balasubramaniam
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, Tennessee, USA
| | - Benem-Orom Davids
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York City, New York, USA
| | - Thomas Hollis
- Department of Biochemistry and Center for Structural Biology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Jamaine Davis
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, Tennessee, USA
| | - Bajarang Kumbhar
- Department of Biological Sciences, Sunandan Divatia School of Science, SVKM's NMIMS (Deemed-to-be-) University, Mumbai, Maharashtra, India
| | - Chandravanu Dash
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, Tennessee, USA; Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee, USA; Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, USA.
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Prakash P, Khodke P, Balasubramaniam M, Davids BO, Hollis T, Davis J, Pandhare J, Kumbhar B, Dash C. Three Prime Repair Exonuclease 1 preferentially degrades the integration-incompetent HIV-1 DNA through favorable kinetics, thermodynamic, structural and conformational properties. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.19.585766. [PMID: 38562877 PMCID: PMC10983988 DOI: 10.1101/2024.03.19.585766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
HIV-1 integration into the human genome is dependent on 3'-processing of the reverse transcribed viral DNA. Recently, we reported that the cellular Three Prime Repair Exonuclease 1 (TREX1) enhances HIV-1 integration by degrading the unprocessed viral DNA, while the integration-competent 3'-processed DNA remained resistant. Here, we describe the mechanism by which the 3'-processed HIV-1 DNA resists TREX1-mediated degradation. Our kinetic studies revealed that the rate of cleavage (kcat) of the 3'-processed DNA was significantly lower than the unprocessed HIV-1 DNA by TREX1. The efficiency of degradation (kcat/KM) of the 3'-processed DNA was also significantly lower than the unprocessed DNA. Furthermore, the binding affinity (Kd) of TREX1 was markedly lower to the 3'-processed DNA compared to the unprocessed DNA. Molecular docking and dynamics studies revealed distinct conformational binding modes of TREX1 with the 3'-processed and unprocessed HIV-1 DNA. Particularly, the unprocessed DNA was favorably positioned in the active site with polar interactions with the catalytic residues of TREX1. Additionally, a stable complex was formed between TREX1 and the unprocessed DNA compared the 3'-processed DNA. These results pinpoint the biochemical mechanism by which TREX1 preferentially degrades the integration-incompetent HIV-1 DNA and reveal the unique structural and conformational properties of the integration-competent 3'-processed HIV-1 DNA.
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Affiliation(s)
- Prem Prakash
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, Tennessee, 37208, USA
| | - Purva Khodke
- Sunandan Divatia School of Science, NMIMS University, Mumbai, 400056, India
| | - Muthukumar Balasubramaniam
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, Tennessee, 37208, USA
| | - Benem-Orom Davids
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York City, New York, 10032, USA
| | - Thomas Hollis
- Department of Biochemistry and Center for Structural Biology, Wake Forest University School of Medicine, Winston-Salem, NC, 27157, USA
| | - Jamaine Davis
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, Tennessee, 37208, USA
| | - Jui Pandhare
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee, 37208, USA
| | - Bajarang Kumbhar
- Sunandan Divatia School of Science, NMIMS University, Mumbai, 400056, India
| | - Chandravanu Dash
- Department of Biochemistry, Cancer Biology, Neuroscience and Pharmacology, Meharry Medical College, Nashville, Tennessee, 37208, USA
- Center for AIDS Health Disparities Research, Meharry Medical College, Nashville, Tennessee, 37208, USA
- Department of Microbiology, Immunology, and Physiology, Meharry Medical College, Nashville, Tennessee, 37208, USA
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Justiz-Vaillant AA, Gopaul D, Soodeen S, Arozarena-Fundora R, Barbosa OA, Unakal C, Thompson R, Pandit B, Umakanthan S, Akpaka PE. Neuropsychiatric Systemic Lupus Erythematosus: Molecules Involved in Its Imunopathogenesis, Clinical Features, and Treatment. Molecules 2024; 29:747. [PMID: 38398500 PMCID: PMC10892692 DOI: 10.3390/molecules29040747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 01/14/2024] [Accepted: 01/16/2024] [Indexed: 02/25/2024] Open
Abstract
Systemic lupus erythematosus (SLE) is an idiopathic chronic autoimmune disease that can affect any organ in the body, including the neurological system. Multiple factors, such as environmental (infections), genetic (many HLA alleles including DR2 and DR3, and genes including C4), and immunological influences on self-antigens, such as nuclear antigens, lead to the formation of multiple autoantibodies that cause deleterious damage to bodily tissues and organs. The production of autoantibodies, such as anti-dsDNA, anti-SS(A), anti-SS(B), anti-Smith, and anti-neuronal DNA are characteristic features of this disease. This autoimmune disease results from a failure of the mechanisms responsible for maintaining self-tolerance in T cells, B cells, or both. Immune complexes, circulating antibodies, cytokines, and autoreactive T lymphocytes are responsible for tissue injury in this autoimmune disease. The diagnosis of SLE is a rheumatological challenge despite the availability of clinical criteria. NPSLE was previously referred to as lupus cerebritis or lupus sclerosis. However, these terms are no longer recommended because there is no definitive pathological cause for the neuropsychiatric manifestations of SLE. Currently, the treatment options are primarily based on symptomatic presentations. These include the use of antipsychotics, antidepressants, and anxiolytic medications for the treatment of psychiatric and mood disorders. Antiepileptic drugs to treat seizures, and immunosuppressants (e.g., corticosteroids, azathioprine, and mycophenolate mofetil), are directed against inflammatory responses along with non-pharmacological interventions.
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Affiliation(s)
- Angel A. Justiz-Vaillant
- Department of Para-Clinical Sciences, University of the West Indies, St. Augustine Campus, St. Augustine 00000, Trinidad and Tobago; (S.S.); (C.U.); (R.T.); (B.P.); (P.E.A.)
| | - Darren Gopaul
- Port of Spain General Hospital, University of the West Indies, St. Augustine Campus, St. Augustine 00000, Trinidad and Tobago;
| | - Sachin Soodeen
- Department of Para-Clinical Sciences, University of the West Indies, St. Augustine Campus, St. Augustine 00000, Trinidad and Tobago; (S.S.); (C.U.); (R.T.); (B.P.); (P.E.A.)
| | - Rodolfo Arozarena-Fundora
- Eric Williams Medical Sciences Complex, North Central Regional Health Authority, Champs Fleurs, San Juan 00000, Trinidad and Tobago; (R.A.-F.); (O.A.B.)
- Department of Clinical and Surgical Sciences, Faculty of Medical Sciences, The University of the West Indies, St. Augustine 00000, Trinidad and Tobago
| | - Odette Arozarena Barbosa
- Eric Williams Medical Sciences Complex, North Central Regional Health Authority, Champs Fleurs, San Juan 00000, Trinidad and Tobago; (R.A.-F.); (O.A.B.)
| | - Chandrashehkar Unakal
- Department of Para-Clinical Sciences, University of the West Indies, St. Augustine Campus, St. Augustine 00000, Trinidad and Tobago; (S.S.); (C.U.); (R.T.); (B.P.); (P.E.A.)
| | - Reinand Thompson
- Department of Para-Clinical Sciences, University of the West Indies, St. Augustine Campus, St. Augustine 00000, Trinidad and Tobago; (S.S.); (C.U.); (R.T.); (B.P.); (P.E.A.)
| | - Bijay Pandit
- Department of Para-Clinical Sciences, University of the West Indies, St. Augustine Campus, St. Augustine 00000, Trinidad and Tobago; (S.S.); (C.U.); (R.T.); (B.P.); (P.E.A.)
| | - Srikanth Umakanthan
- Department of Para-Clinical Sciences, University of the West Indies, St. Augustine Campus, St. Augustine 00000, Trinidad and Tobago; (S.S.); (C.U.); (R.T.); (B.P.); (P.E.A.)
| | - Patrick E. Akpaka
- Department of Para-Clinical Sciences, University of the West Indies, St. Augustine Campus, St. Augustine 00000, Trinidad and Tobago; (S.S.); (C.U.); (R.T.); (B.P.); (P.E.A.)
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Huang KW, Wu CY, Toh SI, Liu TC, Tu CI, Lin YH, Cheng AJ, Kao YT, Chu JW, Hsiao YY. Molecular insight into the specific enzymatic properties of TREX1 revealing the diverse functions in processing RNA and DNA/RNA hybrids. Nucleic Acids Res 2023; 51:11927-11940. [PMID: 37870446 PMCID: PMC10681709 DOI: 10.1093/nar/gkad910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 09/28/2023] [Accepted: 10/06/2023] [Indexed: 10/24/2023] Open
Abstract
In various autoimmune diseases, dysfunctional TREX1 (Three prime Repair Exonuclease 1) leads to accumulation of endogenous single-stranded DNA (ssDNA), double-stranded DNA (dsDNA) and DNA/RNA hybrids in the cytoplasm and triggers immune activation through the cGAS-STING pathway. Although inhibition of TREX1 could be a useful strategy for cancer immunotherapy, profiling cellular functions in terms of its potential substrates is a key step. Particularly important is the functionality of processing DNA/RNA hybrids and RNA substrates. The exonuclease activity measurements conducted here establish that TREX1 can digest both ssRNA and DNA/RNA hybrids but not dsRNA. The newly solved structures of TREX1-RNA product and TREX1-nucleotide complexes show that 2'-OH does not impose steric hindrance or specific interactions for the recognition of RNA. Through all-atom molecular dynamics simulations, we illustrate that the 2'-OH-mediated intra-chain hydrogen bonding in RNA would affect the binding with TREX1 and thereby reduce the exonuclease activity. This notion of higher conformational rigidity in RNA leading TREX1 to exhibit weaker catalytic cleavage is further validated by the binding affinity measurements with various synthetic DNA-RNA junctions. The results of this work thus provide new insights into the mechanism by which TREX1 processes RNA and DNA/RNA hybrids and contribute to the molecular-level understanding of the complex cellular functions of TREX1 as an exonuclease.
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Affiliation(s)
- Kuan-Wei Huang
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
| | - Chia-Yun Wu
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
| | - Shu-Ing Toh
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
| | - Tung-Chang Liu
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
| | - Chun-I Tu
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
| | - Yin-Hsin Lin
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
| | - An-Ju Cheng
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
| | - Ya-Ting Kao
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Institute of Bioinformatics and Systems Biology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Center for Intelligent Drug Systems and Smart Bio-devices (IDSB), National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
| | - Jhih-Wei Chu
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Institute of Bioinformatics and Systems Biology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Center for Intelligent Drug Systems and Smart Bio-devices (IDSB), National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
| | - Yu-Yuan Hsiao
- Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Institute of Bioinformatics and Systems Biology, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Center for Intelligent Drug Systems and Smart Bio-devices (IDSB), National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan
- Drug Development and Value Creation Research Center, Center for Cancer Research, Kaohsiung Medical University, Kaohsiung 807378, Taiwan
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 807378, Taiwan
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5
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Fang L, Ying S, Xu X, Wu D. TREX1 cytosolic DNA degradation correlates with autoimmune disease and cancer immunity. Clin Exp Immunol 2023; 211:193-207. [PMID: 36745566 PMCID: PMC10038326 DOI: 10.1093/cei/uxad017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 01/22/2023] [Accepted: 02/03/2023] [Indexed: 02/07/2023] Open
Abstract
The N-terminal domain of Three Prime Repair Exonuclease 1 (TREX1) is catalytically active and can degrade dsDNA or ssDNA in the cytosol, whereas the C-terminal domain is primarily involved in protein localization. TREX1 deficiency induces cytosolic DNA accumulation as well as activation of the cGAS-STING-IFN signaling pathway, which results in tissue inflammation and autoimmune diseases. Furthermore, TREX1 expression in cancer immunity can be adaptively regulated to promote tumor proliferation, making it a promising therapeutic target.
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Affiliation(s)
- Liwei Fang
- Pediatric Neurorehabilitation Center, Pediatric Department, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Songcheng Ying
- Department of Immunology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Xi Xu
- Department of Plastic Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - De Wu
- Pediatric Neurorehabilitation Center, Pediatric Department, The First Affiliated Hospital of Anhui Medical University, Hefei, China
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Zhou W, Richmond-Buccola D, Wang Q, Kranzusch PJ. Structural basis of human TREX1 DNA degradation and autoimmune disease. Nat Commun 2022; 13:4277. [PMID: 35879334 PMCID: PMC9314330 DOI: 10.1038/s41467-022-32055-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 07/11/2022] [Indexed: 01/13/2023] Open
Abstract
TREX1 is a cytosolic DNA nuclease essential for regulation of cGAS-STING immune signaling. Existing structures of mouse TREX1 establish a mechanism of DNA degradation and provide a key model to explain autoimmune disease, but these structures incompletely explain human disease-associated mutations and have limited ability to guide development of small-molecule therapeutics. Here we determine crystal structures of human TREX1 in apo and DNA-bound conformations that provide high-resolution detail of all human-specific features. A 1.25 Å structure of human TREX1 establishes a complete model of solvation of the exonuclease active site and a 2.2 Å structure of the human TREX1-DNA complex enables identification of specific substitutions involved in DNA recognition. We map each TREX1 mutation associated with autoimmune disease and establish distinct categories of substitutions predicted to impact enzymatic function, protein stability, and interaction with cGAS-DNA liquid droplets. Our results explain how human-specific substitutions regulate TREX1 function and provide a foundation for structure-guided design of TREX1 therapeutics.
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Affiliation(s)
- Wen Zhou
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.
| | - Desmond Richmond-Buccola
- Department of Microbiology, Harvard Medical School, Boston, MA, 02115, USA
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
| | - Qiannan Wang
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Philip J Kranzusch
- Department of Microbiology, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
- Parker Institute for Cancer Immunotherapy at Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
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Wang Q, Du J, Hua S, Zhao K. TREX1 Plays Multiple Roles in Human Diseases. Cell Immunol 2022; 375:104527. [DOI: 10.1016/j.cellimm.2022.104527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/12/2022] [Accepted: 04/10/2022] [Indexed: 11/15/2022]
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Systemic lupus erythematosus overlapping dermatomyositis owing to a heterozygous TREX1 Asp130Asn missense mutation. Clin Immunol 2021; 227:108732. [PMID: 33892200 DOI: 10.1016/j.clim.2021.108732] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 11/21/2022]
Abstract
The 3' repair exonuclease 1 (TREX1) gene encodes a nuclear protein with 3' exonuclease activity, and the mutations have been associated with autoimmune diseases. Herein, we performed genetic analysis for the TREX1 gene in 55 patients with systemic lupus erythematosus (SLE). We identified one SLE patient with overlapping dermatomyositis having a heterozygous p.Asp130Asn mutation in the TREX1 gene. The patient had a high level of serum interferon (IFN)-α compared with that in healthy controls and other patients with SLE. In addition, the patient expressed elevated IFN signature genes compared with healthy controls. Our molecular dynamics simulation of the TREX1 protein in a complex with double-stranded DNA revealed that the D130N mutant causes significant changes in the active site's interaction network. One of our cases exhibited a heterozygous TREX1 p.Asp130Asn mutation that contributed to the type I IFN pathway, which may lead to the development of a severe SLE phenotype.
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Hemphill WO, Simpson SR, Liu M, Salsbury FR, Hollis T, Grayson JM, Perrino FW. TREX1 as a Novel Immunotherapeutic Target. Front Immunol 2021; 12:660184. [PMID: 33868310 PMCID: PMC8047136 DOI: 10.3389/fimmu.2021.660184] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/15/2021] [Indexed: 12/13/2022] Open
Abstract
Mutations in the TREX1 3' → 5' exonuclease are associated with a spectrum of autoimmune disease phenotypes in humans and mice. Failure to degrade DNA activates the cGAS-STING DNA-sensing pathway signaling a type-I interferon (IFN) response that ultimately drives immune system activation. TREX1 and the cGAS-STING DNA-sensing pathway have also been implicated in the tumor microenvironment, where TREX1 is proposed to degrade tumor-derived DNA that would otherwise activate cGAS-STING. If tumor-derived DNA were not degraded, the cGAS-STING pathway would be activated to promote IFN-dependent antitumor immunity. Thus, we hypothesize TREX1 exonuclease inhibition as a novel immunotherapeutic strategy. We present data demonstrating antitumor immunity in the TREX1 D18N mouse model and discuss theory surrounding the best strategy for TREX1 inhibition. Potential complications of TREX1 inhibition as a therapeutic strategy are also discussed.
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Affiliation(s)
- Wayne O. Hemphill
- Department of Biochemistry, Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Sean R. Simpson
- Department of Biochemistry, Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Mingyong Liu
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Freddie R. Salsbury
- Department of Physics, Wake Forest University, Winston-Salem, NC, United States
| | - Thomas Hollis
- Department of Biochemistry, Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Jason M. Grayson
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Fred W. Perrino
- Department of Biochemistry, Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC, United States
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Tao SS, Wu GC, Zhang Q, Zhang TP, Leng RX, Pan HF, Ye DQ. TREX1 As a Potential Therapeutic Target for Autoimmune and Inflammatory Diseases. Curr Pharm Des 2020; 25:3239-3247. [PMID: 31475890 DOI: 10.2174/1381612825666190902113218] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 08/27/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND OBJECTIVES The 3' repair exonuclease 1 (TREX1) gene is the major DNA-specific 3'-5 'exonuclease of mammalian cells which reduces single- and double-stranded DNA (ssDNA and dsDNA) to prevent undue immune activation mediated by the nucleic acid. TREX1 is also a crucial suppressor of selfrecognition that protects the host from inappropriate autoimmune activations. It has been revealed that TREX1 function is necessary to prevent host DNA accumulating after cell death which could actuate an autoimmune response. In the manuscript, we will discuss in detail the latest advancement to study the role of TREX1 in autoimmune disease. METHODS As a pivotal cytoprotective, antioxidant, anti-apoptotic, immunosuppressive, as well as an antiinflammatory molecule, the functional mechanisms of TREX1 were multifactorial. In this review, we will briefly summarize the latest advancement in studying the role of TREX1 in autoimmune disease, and discuss its potential as a therapeutic target for these diseases. RESULTS Deficiency of TREX1 in human patients and murine models is characterized by systemic inflammation and the disorder of TREX1 functions drives inflammatory responses leading to autoimmune disease. Moreover, much more studies revealed that mutations in TREX1 have been associated with a range of autoimmune disorders. But it is also unclear whether the mutations of TREX1 play a causal role in the disease progression, and whether manipulation of TREX1 has a beneficial effect in the treatment of autoimmune diseases. CONCLUSION Integration of functional TREX1 biology into autoimmune diseases may further deepen our understanding of the development and pathogenesis of autoimmune diseases and provide new clues and evidence for the treatment of autoimmune diseases.
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Affiliation(s)
- Sha-Sha Tao
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, China
| | - Guo-Cui Wu
- School of Nursing, Anhui Medical University, 15 Feicui Road, Hefei, Anhui, China
| | - Qin Zhang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, China
| | - Tian-Ping Zhang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, China
| | - Rui-Xue Leng
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, China
| | - Hai-Feng Pan
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, China
| | - Dong-Qing Ye
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, 81 Meishan Road, Hefei, Anhui, China
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Simpson SR, Hemphill WO, Hudson T, Perrino FW. TREX1 - Apex predator of cytosolic DNA metabolism. DNA Repair (Amst) 2020; 94:102894. [PMID: 32615442 DOI: 10.1016/j.dnarep.2020.102894] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Accepted: 06/03/2020] [Indexed: 12/13/2022]
Abstract
The cytosolic Three prime Repair EXonuclease 1 (TREX1) is a powerful DNA-degrading enzyme required for clearing cytosolic DNA to prevent aberrant inflammation and autoimmunity. In the absence of TREX1 activity, cytosolic DNA pattern recognition receptors of the innate immune system are constitutively activated by undegraded TREX1 substrates. This triggers a chronic inflammatory response in humans expressing mutant TREX1 alleles, eliciting a spectrum of rare autoimmune diseases dependent on the nature of the mutation. The precise origins of cytosolic DNA targeted by TREX1 continue to emerge, but DNA emerging from the nucleus or taken up by the cell could represent potential sources. In this Review, we explore the biochemical and immunological data supporting the role of TREX1 in suppressing cytosolic DNA sensing, and discuss the possibility that TREX1 may contribute to maintenance of genome integrity.
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Affiliation(s)
- Sean R Simpson
- Department of Biochemistry, Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Wayne O Hemphill
- Department of Biochemistry, Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Teesha Hudson
- Department of Biochemistry, Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - Fred W Perrino
- Department of Biochemistry, Center for Structural Biology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
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Matz KM, Guzman RM, Goodman AG. The Role of Nucleic Acid Sensing in Controlling Microbial and Autoimmune Disorders. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 345:35-136. [PMID: 30904196 DOI: 10.1016/bs.ircmb.2018.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Innate immunity, the first line of defense against invading pathogens, is an ancient form of host defense found in all animals, from sponges to humans. During infection, innate immune receptors recognize conserved molecular patterns, such as microbial surface molecules, metabolites produces during infection, or nucleic acids of the microbe's genome. When initiated, the innate immune response activates a host defense program that leads to the synthesis proteins capable of pathogen killing. In mammals, the induction of cytokines during the innate immune response leads to the recruitment of professional immune cells to the site of infection, leading to an adaptive immune response. While a fully functional innate immune response is crucial for a proper host response and curbing microbial infection, if the innate immune response is dysfunctional and is activated in the absence of infection, autoinflammation and autoimmune disorders can develop. Therefore, it follows that the innate immune response must be tightly controlled to avoid an autoimmune response from host-derived molecules, yet still unencumbered to respond to infection. In this review, we will focus on the innate immune response activated from cytosolic nucleic acids, derived from the microbe or host itself. We will depict how viruses and bacteria activate these nucleic acid sensing pathways and their mechanisms to inhibit the pathways. We will also describe the autoinflammatory and autoimmune disorders that develop when these pathways are hyperactive. Finally, we will discuss gaps in knowledge with regard to innate immune response failure and identify where further research is needed.
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Affiliation(s)
- Keesha M Matz
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - R Marena Guzman
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Alan G Goodman
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA, United States; Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States.
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Anunobi R, Boone BA, Cheh N, Tang D, Kang R, Loux T, Lotze MT, Zeh HJ. Extracellular DNA promotes colorectal tumor cell survival after cytotoxic chemotherapy. J Surg Res 2018; 226:181-191. [DOI: 10.1016/j.jss.2018.02.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/09/2018] [Accepted: 02/20/2018] [Indexed: 12/15/2022]
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Structural basis for overhang excision and terminal unwinding of DNA duplexes by TREX1. PLoS Biol 2018; 16:e2005653. [PMID: 29734329 PMCID: PMC5957452 DOI: 10.1371/journal.pbio.2005653] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/17/2018] [Accepted: 04/03/2018] [Indexed: 01/12/2023] Open
Abstract
Three prime repair exonuclease 1 (TREX1) is an essential exonuclease in mammalian cells, and numerous in vivo and in vitro data evidenced its participation in immunity regulation and in genotoxicity remediation. In these very complicated cellular functions, the molecular mechanisms by which duplex DNA substrates are processed are mostly elusive because of the lack of structure information. Here, we report multiple crystal structures of TREX1 complexed with various substrates to provide the structure basis for overhang excision and terminal unwinding of DNA duplexes. The substrates were designed to mimic the intermediate structural DNAs involved in various repair pathways. The results showed that the Leu24-Pro25-Ser26 cluster of TREX1 served to cap the nonscissile 5′-end of the DNA for precise removal of the short 3′-overhang in L- and Y-structural DNA or to wedge into the double-stranded region for further digestion along the duplex. Biochemical assays were also conducted to demonstrate that TREX1 can indeed degrade double-stranded DNA (dsDNA) to a full extent. Overall, this study provided unprecedented knowledge at the molecular level on the enzymatic substrate processing involved in prevention of immune activation and in responses to genotoxic stresses. For example, Arg128, whose mutation in TREX1 was linked to a disease state, were shown to exhibit consistent interaction patterns with the nonscissile strand in all of the structures we solved. Such structure basis is expected to play an indispensable role in elucidating the functional activities of TREX1 at the cellular level and in vivo. Three prime repair exonuclease 1 (TREX1) was shown to participate in various cellular events such as DNA repair, immunity regulation, and viral infection. In addition to relating to autoimmune diseases, this exonuclease also acts as a potential protein target for anticancer or antiviral therapies. A key for such broad attendance of TREX1 is the activities of precise trimming of the 3′-overhang in a double-stranded (dsDNA) and breaking of the terminal base pairing of the duplex. Here, we designed a series of structural DNA substrates and activity assays to delineate the underlying mechanisms. The structures newly resolved in this work indicated that the Leu24-Pro25-Ser26 cluster of TREX1 is essential for the enzyme to carry out the aforementioned activities. Together, our results established an integrated structure view into the versatile exonuclease functions of TREX1 and illuminated the molecular origin for the unique catalytic properties of TREX1 in processing various DNA intermediates in DNA repair and in cytosolic immunity regulation.
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Li P, Du J, Goodier JL, Hou J, Kang J, Kazazian HH, Zhao K, Yu XF. Aicardi-Goutières syndrome protein TREX1 suppresses L1 and maintains genome integrity through exonuclease-independent ORF1p depletion. Nucleic Acids Res 2017; 45:4619-4631. [PMID: 28334850 PMCID: PMC5416883 DOI: 10.1093/nar/gkx178] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 03/11/2017] [Indexed: 12/22/2022] Open
Abstract
Maintaining genome integrity is important for cells and damaged DNA triggers autoimmunity. Previous studies have reported that Three-prime repair exonuclease 1(TREX1), an endogenous DNA exonuclease, prevents immune activation by depleting damaged DNA, thus preventing the development of certain autoimmune diseases. Consistently, mutations in TREX1 are linked with autoimmune diseases such as systemic lupus erythematosus, Aicardi–Goutières syndrome (AGS) and familial chilblain lupus. However, TREX1 mutants competent for DNA exonuclease activity are also linked to AGS. Here, we report a nuclease-independent involvement of TREX1 in preventing the L1 retrotransposon-induced DNA damage response. TREX1 interacted with ORF1p and altered its intracellular localization. Furthermore, TREX1 triggered ORF1p depletion and reduced the L1-mediated nicking of genomic DNA. TREX1 mutants related to AGS were deficient in inducing ORF1p depletion and could not prevent L1-mediated DNA damage. Therefore, our findings not only reveal a new mechanism for TREX1-mediated L1 suppression and uncover a new function for TREX1 in protein destabilization, but they also suggest a novel mechanism for TREX1-mediated suppression of innate immune activation through maintaining genome integrity.
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Affiliation(s)
- Peng Li
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, Jilin 130061, China
| | - Juan Du
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, Jilin 130061, China
| | - John L Goodier
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jingwei Hou
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, Jilin 130061, China
| | - Jian Kang
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, Jilin 130061, China
| | - Haig H Kazazian
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ke Zhao
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, Jilin 130061, China
| | - Xiao-Fang Yu
- Institute of Virology and AIDS Research, First Hospital of Jilin University, Changchun, Jilin 130061, China.,Bloomberg School of Public Health, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Fisher C. Recent Insights into the Control of Human Papillomavirus (HPV) Genome Stability, Loss, and Degradation. J Clin Med 2015; 4:204-30. [PMID: 25798290 PMCID: PMC4366058 DOI: 10.3390/jcm4020204] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Most human papillomavirus (HPV) antiviral strategies have focused upon inhibiting viral DNA replication, but it is increasingly apparent that viral DNA levels can be chemically controlled by approaches that promote its instability. HPVs and other DNA viruses have a tenuous relationship with their hosts. They must replicate and hide from the DNA damage response (DDR) and innate immune systems, which serve to protect cells from foreign or “non-self” DNA, and yet they draft these same systems to support their life cycles. DNA binding antiviral agents promoting massive viral DNA instability and elimination are reviewed. Mechanistic studies of these agents have identified genetic antiviral enhancers and repressors, antiviral sensitizers, and host cell elements that protect and stabilize HPV genomes. Viral DNA degradation appears to be an important means of controlling HPV DNA levels in some cases, but the underlying mechanisms remain poorly understood. These findings may prove useful not only for understanding viral DNA persistence but only in devising future antiviral strategies.
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Affiliation(s)
- Chris Fisher
- NanoVir, 4717 Campus, Kalamazoo, MI 49008, USA; ; Tel.: +1-269-372-3261
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Yuan F, Dutta T, Wang L, Song L, Gu L, Qian L, Benitez A, Ning S, Malhotra A, Deutscher MP, Zhang Y. Human DNA Exonuclease TREX1 Is Also an Exoribonuclease That Acts on Single-stranded RNA. J Biol Chem 2015; 290:13344-53. [PMID: 25855793 DOI: 10.1074/jbc.m115.653915] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Indexed: 01/22/2023] Open
Abstract
3' repair exonuclease 1 (TREX1) is a known DNA exonuclease involved in autoimmune disorders and the antiviral response. In this work, we show that TREX1 is also a RNA exonuclease. Purified TREX1 displays robust exoribonuclease activity that degrades single-stranded, but not double-stranded, RNA. TREX1-D200N, an Aicardi-Goutieres syndrome disease-causing mutant, is defective in degrading RNA. TREX1 activity is strongly inhibited by a stretch of pyrimidine residues as is a bacterial homolog, RNase T. Kinetic measurements indicate that the apparent Km of TREX1 for RNA is higher than that for DNA. Like RNase T, human TREX1 is active in degrading native tRNA substrates. Previously reported TREX1 crystal structures have revealed that the substrate binding sites are open enough to accommodate the extra hydroxyl group in RNA, further supporting our conclusion that TREX1 acts on RNA. These findings indicate that its RNase activity needs to be taken into account when evaluating the physiological role of TREX1.
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Affiliation(s)
- Fenghua Yuan
- From the Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136
| | - Tanmay Dutta
- From the Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136
| | - Ling Wang
- the Department of Medicine, Center for Inflammation, Infectious Diseases, and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614, and
| | - Lei Song
- From the Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136
| | - Liya Gu
- the Graduate Center for Toxicology, University of Kentucky College of Medicine, Lexington, Kentucky 40536
| | - Liangyue Qian
- From the Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136
| | - Anaid Benitez
- From the Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136
| | - Shunbin Ning
- the Department of Medicine, Center for Inflammation, Infectious Diseases, and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614, and
| | - Arun Malhotra
- From the Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136
| | - Murray P Deutscher
- From the Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136
| | - Yanbin Zhang
- From the Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136,
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Exonuclease TREX1 degrades double-stranded DNA to prevent spontaneous lupus-like inflammatory disease. Proc Natl Acad Sci U S A 2015; 112:5117-22. [PMID: 25848017 DOI: 10.1073/pnas.1423804112] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The TREX1 gene encodes a potent DNA exonuclease, and mutations in TREX1 cause a spectrum of lupus-like autoimmune diseases. Most lupus patients develop autoantibodies to double-stranded DNA (dsDNA), but the source of DNA antigen is unknown. The TREX1 D18N mutation causes a monogenic, cutaneous form of lupus called familial chilblain lupus, and the TREX1 D18N enzyme exhibits dysfunctional dsDNA-degrading activity, providing a link between dsDNA degradation and nucleic acid-mediated autoimmune disease. We determined the structure of the TREX1 D18N protein in complex with dsDNA, revealing how this exonuclease uses a novel DNA-unwinding mechanism to separate the polynucleotide strands for single-stranded DNA (ssDNA) loading into the active site. The TREX1 D18N dsDNA interactions coupled with catalytic deficiency explain how this mutant nuclease prevents dsDNA degradation. We tested the effects of TREX1 D18N in vivo by replacing the TREX1 WT gene in mice with the TREX1 D18N allele. The TREX1 D18N mice exhibit systemic inflammation, lymphoid hyperplasia, vasculitis, and kidney disease. The observed lupus-like inflammatory disease is associated with immune activation, production of autoantibodies to dsDNA, and deposition of immune complexes in the kidney. Thus, dysfunctional dsDNA degradation by TREX1 D18N induces disease in mice that recapitulates many characteristics of human lupus. Failure to clear DNA has long been linked to lupus in humans, and these data point to dsDNA as a key substrate for TREX1 and a major antigen source in mice with dysfunctional TREX1 enzyme.
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Human Disease Phenotypes Associated With Mutations in TREX1. J Clin Immunol 2015; 35:235-43. [DOI: 10.1007/s10875-015-0147-3] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 01/19/2015] [Indexed: 12/25/2022]
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Abstract
PURPOSE OF REVIEW Cutaneous Lupus Erythematous (CLE) is an autoimmune disease in which patients may present with isolated skin findings or have CLE associated with underlying systemic disease. The most significant recent studies on its pathogenesis and therapeutic management are reviewed here. RECENT FINDINGS Patients with subacute and Discoid Lupus Erythematous had elevated Interferon score, about a third of all cases of SCLE could be attributed to previous drug exposure, and smoking may be more closely associated with CLE than Systemic Lupus Erythematous (SLE). An underlying genetic defect in some subsets of CLE patients may also be shared with SLE. Efficacy of antimalarial therapy is enhanced by increasing treatment duration or maintaining higher blood drug concentrations. Combination antimalarials that include quinacrine, thalidomide analogs, and Mycophenalate Mofetil may also be effective in refractory CLE. SUMMARY The pathogenesis of CLE remains unclear, and is likely multifactorial. Identified associations with subsets of CLE suggest future research questions in CLE pathogenesis. Subsets of CLE associated with interface dermatitis may share an underlying genetic defect in interferon signaling with SLE. The Cutaneous Lupus Disease Area and Severity Index is a valuable and widely used tool allowing standardized assessment and reporting of cutaneous disease activity and damage. More evidence is available to guide treatment of refractory CLE, but larger studies are needed. VIDEO ABSTRACT http://links.lww.com/COR/A4.
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Fye JM, Coffin SR, Orebaugh CD, Hollis T, Perrino FW. The Arg-62 residues of the TREX1 exonuclease act across the dimer interface contributing to catalysis in the opposing protomers. J Biol Chem 2014; 289:11556-11565. [PMID: 24616097 DOI: 10.1074/jbc.m114.559252] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
TREX1 is a 3'-deoxyribonuclease that degrades single- and double-stranded DNA (ssDNA and dsDNA) to prevent inappropriate nucleic acid-mediated immune activation. More than 40 different disease-causing TREX1 mutations have been identified exhibiting dominant and recessive genetic phenotypes in a spectrum of autoimmune disorders. Mutations in TREX1 at positions Asp-18 and Asp-200 to His and Asn exhibit dominant autoimmune phenotypes associated with the clinical disorders familial chilblain lupus and Aicardi-Goutières syndrome. Our previous biochemical studies showed that the TREX1 dominant autoimmune disease phenotype depends upon an intact DNA-binding process coupled with dysfunctional active site chemistry. Studies here show that the TREX1 Arg-62 residues extend across the dimer interface into the active site of the opposing protomer to coordinate substrate DNA and to affect catalysis in the opposing protomer. The TREX1(R62A/R62A) homodimer exhibits ∼50-fold reduced ssDNA and dsDNA degradation activities relative to TREX1(WT). The TREX1 D18H, D18N, D200H, and D200N dominant mutant enzymes were prepared as compound heterodimers with the TREX1 R62A substitution in the opposing protomer. The TREX1(D18H/R62A), TREX1(D18N/R62A), TREX1(D200H/R62A), and TREX1(D200N/R62A) compound heterodimers exhibit higher levels of ss- and dsDNA degradation activities than the homodimers demonstrating the requirement for TREX1 Arg-62 residues to provide necessary structural elements for full catalytic activity in the opposing TREX1 protomer. This concept is further supported by the loss of dominant negative effects in the TREX1 D18H, D18N, D200H, and D200N compound heterodimers. These data provide compelling evidence for the required TREX1 dimeric structure for full catalytic function.
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Affiliation(s)
- Jason M Fye
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157
| | - Stephanie R Coffin
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157
| | - Clinton D Orebaugh
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157
| | - Thomas Hollis
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157
| | - Fred W Perrino
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157.
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Abe J, Nakamura K, Nishikomori R, Kato M, Mitsuiki N, Izawa K, Awaya T, Kawai T, Yasumi T, Toyoshima I, Hasegawa K, Ohshima Y, Hiragi T, Sasahara Y, Suzuki Y, Kikuchi M, Osaka H, Ohya T, Ninomiya S, Fujikawa S, Akasaka M, Iwata N, Kawakita A, Funatsuka M, Shintaku H, Ohara O, Ichinose H, Heike T. A nationwide survey of Aicardi-Goutières syndrome patients identifies a strong association between dominant TREX1 mutations and chilblain lesions: Japanese cohort study. Rheumatology (Oxford) 2013; 53:448-58. [PMID: 24300241 DOI: 10.1093/rheumatology/ket372] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVES Aicardi-Goutières syndrome (AGS) is a rare, genetically determined, early onset progressive encephalopathy associated with autoimmune manifestations. AGS is usually inherited in an autosomal recessive manner. The disease is rare, therefore the clinical manifestations and genotype-phenotype correlations, particularly with regard to autoimmune diseases, are still unclear. Here we performed a nationwide survey of AGS patients in Japan and analysed the genetic and clinical data. METHODS Patients were recruited via questionnaires sent to paediatric or adult neurologists in Japanese hospitals and institutions. Genetic analysis was performed and clinical data were collected. RESULTS Fourteen AGS patients were identified from 13 families; 10 harboured genetic mutations. Three patients harboured dominant-type TREX1 mutations. These included two de novo cases: one caused by a novel heterozygous p.His195Tyr mutation and the other by a novel somatic mosaicism resulting in a p.Asp200Asn mutation. Chilblain lesions were observed in all patients harbouring dominant-type TREX1 mutations. All three patients harbouring SAMHD1 mutations were diagnosed with autoimmune diseases, two with SLE and one with SS. The latter is the first reported case. CONCLUSION This study is the first to report a nationwide AGS survey, which identified more patients with sporadic AGS carrying de novo dominant-type TREX1 mutations than expected. There was a strong association between the dominant-type TREX1 mutations and chilblain lesions, and between SAMHD1 mutations and autoimmunity. These findings suggest that rheumatologists should pay attention to possible sporadic AGS cases presenting with neurological disorders and autoimmune manifestations.
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Affiliation(s)
- Junya Abe
- Department of Pediatrics, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
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Tomicic MT, Aasland D, Nikolova T, Kaina B, Christmann M. Human three prime exonuclease TREX1 is induced by genotoxic stress and involved in protection of glioma and melanoma cells to anticancer drugs. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1832-43. [PMID: 23578789 DOI: 10.1016/j.bbamcr.2013.03.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 03/15/2013] [Accepted: 03/29/2013] [Indexed: 11/25/2022]
Abstract
To counteract genotoxic stress, DNA repair functions are in effect. Most of them are constitutively expressed while some of them can be up-regulated depending on the level of DNA damage. In human cells, only few DNA repair functions are subject of induction following DNA damage, and thus there is a need to identify and characterize inducible repair functions more thoroughly. Here, we provide evidence that the "three prime exonuclease I" (TREX1) is up-regulated in human fibroblasts and cancer cells on mRNA and protein level. Transcriptional upregulation of TREX1 was observed upon exposure to ultraviolet light and various anticancer drugs in glioma and malignant melanoma cells. Induction of TREX1 was found following treatment with the crosslinking alkylating agents nimustine, carmustine, fotemustine and the topoisomerase I inhibitor topotecan, but not following temozolomide, etoposide and ionizing radiation. Induction of TREX1 following DNA damage requires the AP-1 components c-Jun and c-Fos, as shown by siRNA knockdown, EMSA experiments, ChIP analysis and reporter assays with the TREX1 promoter and constructs harboring mutations in the AP-1 binding site. To analyze whether TREX1 expression impacts the sensitivity of cancer cells to therapeutics, TREX1 expression was down-regulated by siRNA in malignant glioma and melanoma cells. TREX1 knockdown resulted in enhanced cell death following nimustine, fotemustine and topotecan and to a reduced recovery from the anticancer drug induced block to replication. The data revealed that induction of TREX1 is a survival response evoked by various genotoxic anticancer drugs and identified TREX1 as a potential therapeutic target for anticancer therapy.
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Affiliation(s)
- Maja T Tomicic
- Department of Toxicology, University Medical Center, Mainz, Germany
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