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Sidhar K, Elliott K, Ibrahem M. Heat, Cold, and Environmental Emergencies in Athletes. Clin Sports Med 2023; 42:441-461. [PMID: 37208058 DOI: 10.1016/j.csm.2023.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
With the increase in outdoor events, there is an inevitable rise in climate-related environmental emergencies. Heat exposure can place athletes at risk for life-threatening heatstroke which requires emergent diagnosis and rapid in-field management. Cold exposure can lead to hypothermia, frostbite, and other nonfreezing injuries that require prompt evaluation and management to minimize morbidity and mortality. Altitude exposure can lead to acute mountain sickness or other serious neurologic or pulmonary emergencies. Finally, harsh climate exposure can be life-threatening and require appropriate prevention and event planning.
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Affiliation(s)
- Kartik Sidhar
- Department of Family Medicine, University of Michigan Medical School, 300 North Ingalls Street, NI4C06, Ann Arbor, MI 48109-5435, USA.
| | - Katlyn Elliott
- University of Pittsburgh Medical Center, McKeesport Family Medicine Residency, 2347 5th Avenue, McKeesport, PA 15132, USA
| | - Michael Ibrahem
- University of Pittsburgh Medical Center, Shadyside Family Medicine Residency, 5215 Center Avenue, Pittsburgh, PA 15232, USA
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2
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Schulz N, Müller-Ladner U, Klemm PCM. [30-year-old patient with discolored, painfully swollen fingers]. Dtsch Med Wochenschr 2023; 148:595-596. [PMID: 37105186 DOI: 10.1055/a-2045-5772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Affiliation(s)
- Nils Schulz
- Klinik für Innere Medizin und Rheumatologie, Justus-Liebig-Universität Gießen, Campus Kerckhoff, Bad Nauheim
| | - Ulf Müller-Ladner
- Klinik für Innere Medizin und Rheumatologie, Justus-Liebig-Universität Gießen, Campus Kerckhoff, Bad Nauheim
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3
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Igarashi R, Hoshina T, Oho K, Shimajiri S, Kusuhara K. A Pediatric Case of Gingival Swelling and Chilblains as Previously Unrecognized Manifestations of Chronic Nonbacterial Osteomyelitis. J Clin Rheumatol 2021; 27:e93-e94. [PMID: 31972737 DOI: 10.1097/rhu.0000000000001270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Ryota Igarashi
- From the Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health
| | - Takayuki Hoshina
- From the Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health
| | - Kotaro Oho
- Department of Dentistry and Oral Surgery, University Hospital of Occupational and Environmental Health
| | - Shohei Shimajiri
- Department of Surgical Pathology, School of Medicine, University of Occupational and Environmental Health, Japan
| | - Koichi Kusuhara
- From the Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health
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4
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Shishak M, Shishak S, Rajput S. Differentials of red toes in dermatology – Are COVID toes real? INDIAN JOURNAL OF MEDICAL SCIENCES 2020. [PMCID: PMC7485639 DOI: 10.25259/ijms_93_2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Mansak Shishak
- Department of Dermatology, Indian Spinal Injuries Centre, Vasant Kunj, India,
| | - Sorun Shishak
- Department of Radiation Oncology, All India Institute of Medical Sciences, Ansari Nagar, India,
| | - Smit Rajput
- Department of Internal Medicine, Max Super Speciality Hospital, Saket, New Delhi, India,
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5
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Yi C, Li Q, Xiao J. Familial chilblain lupus due to a novel mutation in TREX1 associated with Aicardi-Goutie'res syndrome. Pediatr Rheumatol Online J 2020; 18:32. [PMID: 32293470 PMCID: PMC7158086 DOI: 10.1186/s12969-020-00423-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 04/03/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Familial chilblain lupus (FCL) is a rare, chronic form of cutaneous lupus erythematosus, which is characterized by painful bluish-red inflammatory cutaneous lesions in acral locations. Mutations in TREX1, SAMHD1 and STING have been described in FCL patients. Less than 10 TREX1 mutation positive FCL families have been described in the literature. CASE PRESENTATION Genetic study was performed in a large, nonconsanguineous Chinese family with 13 members over 4 generations affected by chilblain lupus. Whole exome sequencing was performed for the index patient. Significant variant detection was subsequently validated by resequencing using Sanger sequencing in the index patient and other family members. A novel pathogenic mutation TREX1 p.Asp18His was iditified in the index patient. The mutation was present in affected individuals and was absent in non-affected individuals in the familiy. CONCLUSIONS We present a four-generation Chinese family with FCL caused by a novel heterozygous mutation TREX1 p.Asp18His, which had been reported in a patient with Aicardi-Goutie'res syndrome. This is the first reported Chinese family with FCL based on mutation in TREX1.
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Affiliation(s)
- Cuili Yi
- grid.12955.3a0000 0001 2264 7233Pediatric Rheumatology Unit, Pediatric Department, The First Affilated Hospital of Xiamen University, No. 55 Zhenhai Road, Xiamen, Fujian China
| | - Qiyuan Li
- Genokon Medical Laboratory, Xiamen, China
| | - Jihong Xiao
- Pediatric Rheumatology Unit, Pediatric Department, The First Affilated Hospital of Xiamen University, No. 55 Zhenhai Road, Xiamen, Fujian, China.
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6
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Smith EMD, Lythgoe H, Midgley A, Beresford MW, Hedrich CM. Juvenile-onset systemic lupus erythematosus: Update on clinical presentation, pathophysiology and treatment options. Clin Immunol 2019; 209:108274. [PMID: 31678365 DOI: 10.1016/j.clim.2019.108274] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 10/12/2019] [Accepted: 10/13/2019] [Indexed: 12/25/2022]
Abstract
Juvenile-onset systemic lupus erythematosus (jSLE) accounts for up to 20% of all SLE patients. Key differences between juvenile- and adult-onset (aSLE) disease include higher disease activity, earlier development of damage, and increased use of immunosuppressive treatment in jSLE suggesting (at least partial) infectivity secondary to variable pathomechanisms. While the exact pathophysiology of jSLE remains unclear, genetic factors, immune complex deposition, complement activation, hormonal factors and immune cell dysregulation are involved to variable extents, promising future patient stratification based on immune phenotypes. Though less effective and potentially toxic, jSLE patients are treated based upon evidence from studies in aSLE cohorts. Here, age-specific clinical features of jSLE, underlying pathomechanisms, treatment options and disease outcomes will be addressed. Future directions to improve the care of jSLE patients, including implementation of the Single Hub and Access point for pediatric Rheumatology in Europe (SHARE) recommendations, biomarkers, treat to target and personalized medicine approaches are discussed.
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Affiliation(s)
- Eve Mary Dorothy Smith
- Department of Women's & Children's Health, Institution of Translational Medicine, University of Liverpool, UK; Department of Paediatric Rheumatology, Alder Hey Children's NHS Foundation Trust, Eaton Rd, Liverpool L12 2AP, UK.
| | - Hanna Lythgoe
- Department of Paediatric Rheumatology, Alder Hey Children's NHS Foundation Trust, Eaton Rd, Liverpool L12 2AP, UK
| | - Angela Midgley
- Department of Women's & Children's Health, Institution of Translational Medicine, University of Liverpool, UK
| | - Michael William Beresford
- Department of Women's & Children's Health, Institution of Translational Medicine, University of Liverpool, UK; Department of Paediatric Rheumatology, Alder Hey Children's NHS Foundation Trust, Eaton Rd, Liverpool L12 2AP, UK
| | - Christian Michael Hedrich
- Department of Women's & Children's Health, Institution of Translational Medicine, University of Liverpool, UK; Department of Paediatric Rheumatology, Alder Hey Children's NHS Foundation Trust, Eaton Rd, Liverpool L12 2AP, UK.
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7
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Paradis C, Cadieux-Dion M, Meloche C, Gravel M, Paradis J, Des Roches A, Leclerc G, Cossette P, Begin P. TREX-1-Related Disease Associated with the Presence of Cryofibrinogenemia. J Clin Immunol 2019; 39:118-125. [DOI: 10.1007/s10875-018-0584-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/17/2018] [Indexed: 12/19/2022]
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8
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Li Q, Wu H, Liao W, Zhao M, Chan V, Li L, Zheng M, Chen G, Zhang J, Lau CS, Lu Q. A comprehensive review of immune-mediated dermatopathology in systemic lupus erythematosus. J Autoimmun 2018; 93:1-15. [DOI: 10.1016/j.jaut.2018.07.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 07/05/2018] [Indexed: 12/15/2022]
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9
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Lo MS. Insights Gained From the Study of Pediatric Systemic Lupus Erythematosus. Front Immunol 2018; 9:1278. [PMID: 29922296 PMCID: PMC5996073 DOI: 10.3389/fimmu.2018.01278] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/22/2018] [Indexed: 12/21/2022] Open
Abstract
The pathophysiology of systemic lupus erythematosus (SLE) has been intensely studied but remains incompletely defined. Currently, multiple mechanisms are known to contribute to the development of SLE. These include inadequate clearance of apoptotic debris, aberrant presentation of self nucleic antigens, loss of tolerance, and inappropriate activation of T and B cells. Genetic, hormonal, and environmental influences are also known to play a role. The study of lupus in children, in whom there is presumed to be greater genetic influence, has led to new understandings that are applicable to SLE pathophysiology as a whole. In particular, characterization of inherited disorders associated with excessive type I interferon production has elucidated specific mechanisms by which interferon is induced in SLE. In this review, we discuss several monogenic forms of lupus presenting in childhood and also review recent insights gained from cytokine and autoantibody profiling of pediatric SLE.
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Affiliation(s)
- Mindy S Lo
- Division of Immunology, Boston Children's Hospital, Boston, MA, United States.,Department of Pediatrics, Harvard Medical School, Boston, MA, United States
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10
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Abstract
PURPOSE OF REVIEW Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease known for its clinical heterogeneity. Over time, new insights into the complex genetic origin of SLE have started to explain some of this clinical variability. These findings, reviewed here, have also yielded important understanding in the immune mechanisms behind SLE pathogenesis. RECENT FINDINGS Several new monogenic disorders with lupus-like phenotype have been described. These can be organized into physiologic pathways that parallel mechanisms of disease in SLE. Examples include genes important for DNA damage repair (e.g., TREX1), nucleic acid sensing and type I interferon overproduction (e.g., STING, TREX1), apoptosis (FASLG), tolerance (PRKCD), and clearance of self-antigen (DNASE1L3). Further study of monogenic lupus may lead to better genotype/phenotype correlations in SLE. Eventually, the ability to understand individual patients according to their genetic profile may allow the development of more targeted and personalized approaches to therapy.
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Affiliation(s)
- Mindy S Lo
- Division of Immunology, Boston Children's Hospital, 300 Longwood Ave, Boston, MA, USA.
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
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11
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Kisla Ekinci RM, Balci S, Bisgin A, Altintas DU, Yilmaz M. A homozygote TREX1 mutation in two siblings with different phenotypes: Chilblains and cerebral vasculitis. Eur J Med Genet 2017; 60:690-694. [PMID: 28919362 DOI: 10.1016/j.ejmg.2017.09.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 08/10/2017] [Accepted: 09/10/2017] [Indexed: 10/18/2022]
Abstract
Three prime repair exonuclease 1 degrades single and double stranded DNA with 3'-5' nuclease activity and its mutations are related to type 1 IFN mediated autoinflammation due to accumulated intracellular nucleic acids. To date, several cases of systemic lupus erythematosus, Aicardi-Goutieres syndrome, familial chilblain lupus, retinal vasculopathy-cerebral leukodystrophy have been reported with TREX1 mutations. Chilblain lupus is a skin disease characterized by blue-reddish coloring, swelling or ulcers on acral regions of body such as fingertips, heels, nose and auricles. Central nervous system vasculitis is a prominent cause of childhood strokes. 10 families with familial chilblain lupus related to TREX1 mutations were reported previously in the literature, in which homozygote D18N variant in TREX1 gene was related to chilblains with cerebral vasculitis. In this report, whole-exome-sequencing revealed a homozygote R114C mutation in TREX1 gene was shown in two siblings with recurrent chilblains whom one of them was the second case accompanied by cerebral vasculitis in the literature. As a result, the approach of WES in clinical use revealed a novel mutation in clinically heterogenous patients to provide genetic counseling.
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Affiliation(s)
| | - Sibel Balci
- Department of Pediatric Rheumatology, Cukurova University Faculty of Medicine, Adana, Turkey.
| | - Atil Bisgin
- Department of Medical Genetics, AGENTEM (Adana Genetic Diseases Diagnosis and Treatment Center), Cukurova University Faculty of Medicine, Adana, Turkey.
| | - Derya Ufuk Altintas
- Department of Pediatric Allergy and Immunology, Cukurova University Faculty of Medicine, Adana, Turkey.
| | - Mustafa Yilmaz
- Department of Pediatric Rheumatology, Cukurova University Faculty of Medicine, Adana, Turkey.
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12
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Hansen CB, Callen JP. Current and future treatment options for cutaneous lupus erythematosus. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1048224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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13
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Yun D, Stein SL. Review of the cutaneous manifestations of autoimmune connective tissue diseases in pediatric patients. World J Dermatol 2015; 4:80-94. [DOI: 10.5314/wjd.v4.i2.80] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 02/25/2015] [Accepted: 04/07/2015] [Indexed: 02/06/2023] Open
Abstract
Autoimmune connective tissue diseases are chronic inflammatory disorders associated with complex genetic and environmental interplay resulting in a variety of cutaneous and systemic manifestations. Pediatric onset of these disorders carries a unique diagnostic pressure for the clinician due to the potential years of disease burden and complications. Mortality and morbidity from these disorders has fallen dramatically over the past fifty years due to increasing awareness of these disease sequelae and utilization of systemic treatment modalities when necessary. This review highlights the clinical features that are unique to pediatric presentations of lupus erythematosus, juvenile idiopathic arthritis, juvenile dermatomyositis, juvenile onset systemic sclerosis and morphea. Each of these disorders has a distinct appearance corresponding to a particular cutaneous and systemic clinical course and prognosis. Awareness of the associated potential systemic complications can also alert the clinician to make astute management decisions when confronted with a probable rheumatologic case. Cutaneous symptoms may predate onset of systemic symptoms and by keeping the rheumatologic differential diagnoses in mind, the dermatologist can play a key role in potentially offsetting autoimmune disease burden in children.
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14
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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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15
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Kono DH, Baccala R, Theofilopoulos AN. TLRs and interferons: a central paradigm in autoimmunity. Curr Opin Immunol 2013; 25:720-7. [PMID: 24246388 DOI: 10.1016/j.coi.2013.10.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/06/2013] [Indexed: 01/08/2023]
Abstract
Investigations into the pathogenesis of lupus have largely focused on abnormalities in components of the adaptive immune system. Despite important advances, however, the question about the origin of the pathogenic process, the primary disease trigger, and the dominance of autoantibodies against nuclear components, remained unanswered. Discoveries in the last decade have provided some resolution to these questions by elucidating the central role of nucleic acid-sensing TLRs and the attendant inflammatory response, particularly the production of type I interferons. These priming events are responsible for initiating the adaptive responses that ultimately mediate the pathogenic process.
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Affiliation(s)
- Dwight H Kono
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, United States.
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16
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Rare variants in the TREX1 gene and susceptibility to autoimmune diseases. BIOMED RESEARCH INTERNATIONAL 2013; 2013:471703. [PMID: 24224166 PMCID: PMC3810194 DOI: 10.1155/2013/471703] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 07/18/2013] [Accepted: 09/21/2013] [Indexed: 01/19/2023]
Abstract
TREX1 (DNase III) is an exonuclease involved in response to oxidative stress and apoptosis. Heterozygous mutations in TREX1 were previously observed in patients with systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS). We performed a mutational analysis of the TREX1 gene on three autoimmune diseases: SLE (210 patients) and SS (58 patients), to confirm a TREX1 involvement in the Italian population, and systemic sclerosis (SSc, 150 patients) because it shares similarities with SLE (presence of antinuclear antibodies and connective tissue damage). We observed 7 variations; two of these are novel nonsynonymous variants (p.Glu198Lys and p.Met232Val). They were detected in one SS and in one SSc patient, respectively, and in none of the 200 healthy controls typed in this study and of the 1712 published controls. In silico analysis predicts a possibly damaging role on protein function for both variants. The other 5 variations are synonymous and only one of them is novel (p.Pro48Pro).
This study contributes to the demonstration that TREX1 is involved in autoimmune diseases and proposes that the spectrum of involved autoimmune diseases can be broader and includes SSc. We do not confirm a role of TREX1 variants in SLE.
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Orebaugh CD, Fye JM, Harvey S, Hollis T, Wilkinson JC, Perrino FW. The TREX1 C-terminal region controls cellular localization through ubiquitination. J Biol Chem 2013; 288:28881-92. [PMID: 23979357 DOI: 10.1074/jbc.m113.503391] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
TREX1 is an autonomous 3'-exonuclease that degrades DNA to prevent inappropriate immune activation. The TREX1 protein is composed of 314 amino acids; the N-terminal 242 amino acids contain the catalytic domain, and the C-terminal region (CTR) localizes TREX1 to the cytosolic compartment. In this study, we show that TREX1 modification by ubiquitination is controlled by a highly conserved sequence in the CTR to affect cellular localization. Transfection of TREX1 deletion constructs into human cells demonstrated that this sequence is required for ubiquitination at multiple lysine residues through a "non-canonical" ubiquitin linkage. A proteomic approach identified ubiquilin 1 as a TREX1 CTR-interacting protein, and this interaction was verified in vitro and in vivo. Cotransfection studies indicated that ubiquilin 1 localizes TREX1 to cytosolic punctate structures dependent upon the TREX1 CTR and lysines within the TREX1 catalytic core. Several TREX1 mutants linked to the autoimmune diseases Aicardi-Goutières syndrome and systemic lupus erythematosus that exhibit full catalytic function were tested for altered ubiquitin modification and cellular localization. Our data show that these catalytically competent disease-causing TREX1 mutants exhibit differential levels of ubiquitination relative to WT TREX1, suggesting a novel mechanism of dysfunction. Furthermore, these differentially ubiquitinated disease-causing mutants also exhibit altered ubiquilin 1 co-localization. Thus, TREX1 post-translational modification indicates an additional mechanism by which mutations disrupt TREX1 biology, leading to human autoimmune disease.
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Affiliation(s)
- Clinton D Orebaugh
- From the Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157
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18
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Defects in DNA degradation revealed in crystal structures of TREX1 exonuclease mutations linked to autoimmune disease. DNA Repair (Amst) 2011; 11:65-73. [PMID: 22071149 DOI: 10.1016/j.dnarep.2011.10.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 10/07/2011] [Accepted: 10/07/2011] [Indexed: 12/13/2022]
Abstract
Mutations within the human TREX1 3' exonuclease are associated with Aicardi-Goutières Syndrome (AGS) and familial chilblain lupus (FCL). Both AGS and FCL are autoimmune diseases that result in increased levels of interferon alpha and circulating antibodies to DNA. TREX1 is a member of the endoplasmic reticulum (ER)-associated SET complex and participates in granzyme A-mediated cell death to degrade nicked genomic DNA. The loss of TREX1 activity may result in the accumulation of double-stranded DNA (dsDNA) degradation intermediates that trigger autoimmune activation. The X-ray crystal structures of the TREX1 wt apoprotein, the dominant D200H, D200N and D18N homodimer mutants derived from AGS and FCL patients, as well as the recessive V201D homodimer mutant have been determined. The structures of the D200H and D200N mutant proteins reveal the enzyme has lost coordination of one of the active site metals, and the catalytic histidine (H195) is trapped in a conformation pointing away from the active site. The TREX1 D18N and V201D mutants are able to bind both metals in the active site, but with inter-metal distances that are larger than optimal for catalysis. Additionally, all of the mutant structures reveal a reduced mobility in the catalytic histidine, providing further explanation for the loss of catalytic activity. The structures of the mutant TREX1 proteins provide insight into the dysfunction relating to human disease. Additionally, the TREX1 apoprotein structure together with the previously determined wild type substrate and product structures allow us to propose a distinct mechanism for the TREX1 exonuclease.
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Arias-Santiago SA, Girón-Prieto MS, Callejas-Rubio JL, Fernández-Pugnaire MA, Ortego-Centeno N. Lupus Pernio or Chilblain Lupus? Chest 2009; 136:946-947. [DOI: 10.1378/chest.09-1005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
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