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Ohnishi T, Tran V, Sao K, Ramteke P, Querido W, Barve RA, van de Wetering K, Risbud MV. Loss of function mutation in Ank causes aberrant mineralization and acquisition of osteoblast-like-phenotype by the cells of the intervertebral disc. Cell Death Dis 2023; 14:447. [PMID: 37468461 PMCID: PMC10356955 DOI: 10.1038/s41419-023-05893-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 06/09/2023] [Accepted: 06/15/2023] [Indexed: 07/21/2023]
Abstract
Pathological mineralization of intervertebral disc is debilitating and painful and linked to disc degeneration in a subset of human patients. An adenosine triphosphate efflux transporter, progressive ankylosis (ANK) is a regulator of extracellular inorganic pyrophosphate levels and plays an important role in tissue mineralization. However, the function of ANK in intervertebral disc has not been fully explored. Herein we analyzed the spinal phenotype of Ank mutant mice (ank/ank) with attenuated ANK function. Micro-computed tomography and histological analysis showed that loss of ANK function results in the aberrant annulus fibrosus mineralization and peripheral disc fusions with cranial to caudal progression in the spine. Vertebrae in ank mice exhibit elevated cortical bone mass and increased tissue non-specific alkaline phosphatase-positive endplate chondrocytes with decreased subchondral endplate porosity. The acellular dystrophic mineral inclusions in the annulus fibrosus were localized adjacent to apoptotic cells and cells that acquired osteoblast-like phenotype. Fourier transform infrared spectral imaging showed that the apatite mineral in the outer annulus fibrosus had similar chemical composition to that of vertebral bone. Transcriptomic analysis of annulus fibrosus and nucleus pulposus tissues showed changes in several biological themes with a prominent dysregulation of BMAL1/CLOCK circadian regulation. The present study provides new insights into the role of ANK in the disc tissue compartments and highlights the importance of local inorganic pyrophosphate metabolism in inhibiting the mineralization of this important connective tissue.
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Affiliation(s)
- Takashi Ohnishi
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, 060-8638, Japan
| | - Victoria Tran
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Kimheak Sao
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Pranay Ramteke
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - William Querido
- Department of Bioengineering, Temple University, Philadelphia, PA, 19122, USA
| | - Ruteja A Barve
- Department of Genetics, Genome Technology Access Centre at the McDonnell Genome Institute, Washington University, School of Medicine, St. Louis, MO, 63110, USA
| | - Koen van de Wetering
- Department of Dermatology and Cutaneous Biology, Jefferson Institute of Molecular Medicine and PXE International Center of Excellence in Research and Clinical Care, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Makarand V Risbud
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA.
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The relationship of serum vitamin D receptor levels with disease activity and clinical parameters in patients with ankylosing spondylitis. Turk J Phys Med Rehabil 2019; 65:389-393. [PMID: 31893276 DOI: 10.5606/tftrd.2019.3296] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 10/02/2018] [Indexed: 11/21/2022] Open
Abstract
Objectives The aim of this study was to investigate the relationship between serum vitamin D receptor (SVDR) levels and disease activity parameters in patients with ankylosing spondylitis (AS). Patients and methods Between July 2016 and January 2017, a total of 62 patients (51 males, 11 females; mean age 36.5±12.8 years; range, 23 to 49 years) with AS and 32 healthy volunteers (25 males, 7 females; mean age 41.57±13.6 years; range, 26 to 48 years) were included in the study. The SVDR levels were measured using the enzyme-linked immunosorbent assay. Erythrocyte sedimentation rate (ESR) and serum C-reactive protein (CRP) levels were recorded. The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores were used to assess disease activity. Results Although there was no significant difference between the patient and control groups (p=0.66), SVDR levels were significantly elevated in patients with active AS (BASDAI score ≥4) (p=0.01). The SVDR levels significantly increased in AS patients with peripheral joint involvement and enthesitis (p=0.01, p=0.05, respectively). The SVDR levels significantly elevated in patients treated with non-steroidal anti- inflammatory drugs, compared to those treated with biological agents and control group (p=0.01, p=0.03, respectively). The SVDR levels were positively correlated with the BASDAI, CRP and ESR in the patient group (p=0.01, r=0.751; p=0.01, r=0.75; p=0.01, r=0.81, respectively). Conclusion Our study results suggest that serum SVDR levels are associated with the disease activity and clinical parameters in patients with AS. Based on these findings, SVDR level may be used as a marker of disease activity in AS.
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Neve A, Maruotti N, Corrado A, Cantatore FP. Pathogenesis of ligaments ossification in spondyloarthritis: insights and doubts. Ann Med 2017; 49:196-205. [PMID: 27685190 DOI: 10.1080/07853890.2016.1243802] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Despite intensive research in spondyloarthritis pathogenesis, some important questions still remain unanswered, particularly concerning enthesis new bone formation. Several evidences suggest that it prevalently occurs by endochondral ossification, however it remains to identify factors that can induce and influence its initiation and progression. Recent progress, achieved in animal models and in vitro and genetic association studies, has led us to hypothesize that several systemic factors (adipokines and gut hormones) and local factors (BMP and Wnt signaling) as well as angiogenesis and mechanical stress are involved. We critically review and summarize the available data and delineate the possible mechanisms involved in enthesis ossification, particularly at spinal ligament level. KEY MESSAGES Complete understanding of spondyloarthritis pathophysiology requires insights into inflammation, bone destruction and bone formation, which are all located in entheses and lead all together to ankylosis and functional disability. Several factors probably play a role in the pathogenesis of bone formation in entheses including not only cytokines but also several systemic factors such as adipokines and gut hormones, and local factors, such as BMP and Wnt signaling, as well as angiogenesis and mechanical stress. Data available about pathophysiology of new bone formation in spondyloarthritis are limited and often conflicting and future studies are needed to better delineate it and to develop new therapeutic approaches.
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Affiliation(s)
- Anna Neve
- a Rheumatology Clinic, Department of Medical and Surgical Sciences , University of Foggia Medical School , Foggia , Italy
| | - Nicola Maruotti
- a Rheumatology Clinic, Department of Medical and Surgical Sciences , University of Foggia Medical School , Foggia , Italy
| | - Addolorata Corrado
- a Rheumatology Clinic, Department of Medical and Surgical Sciences , University of Foggia Medical School , Foggia , Italy
| | - Francesco Paolo Cantatore
- a Rheumatology Clinic, Department of Medical and Surgical Sciences , University of Foggia Medical School , Foggia , Italy
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Congenital Cataract in Gpr161vl/vl Mice Is Modified by Proximal Chromosome 15. PLoS One 2017; 12:e0170724. [PMID: 28135291 PMCID: PMC5279759 DOI: 10.1371/journal.pone.0170724] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 01/10/2017] [Indexed: 11/24/2022] Open
Abstract
The morphology and severity of human congenital cataract varies even among individuals with the same mutation, suggesting that genetic background modifies phenotypic penetrance. The spontaneous mouse mutant, vacuolated lens (vl), arose on the C3H/HeSnJ background. The mutation disrupts secondary lens fiber development by E16.5, leading to full penetrance of congenital cataract. The vl locus was mapped to a frameshift deletion in the orphan G protein-coupled receptor, Gpr161, which is expressed in differentiating lens fiber cells. When Gpr161vl/vl C3H mice are crossed to MOLF/EiJ mice an unexpected rescue of cataract is observed, suggesting that MOLF modifiers affect cataract penetrance. Subsequent QTL analysis mapped three modifiers (Modvl3-5: Modifier of vl) and in this study we characterized Modvl4 (Chr15; LOD = 4.4). A Modvl4MOLF congenic was generated and is sufficient to rescue congenital cataract and the lens fiber defect at E16.5. Additional phenotypic analysis on three subcongenic lines narrowed down the interval from 55 to 15Mb. In total only 18 protein-coding genes and 2 micro-RNAs are in this region. Fifteen of the 20 genes show detectable expression in the E16.5 eye. Subsequent expression studies in Gpr161vl/vl and subcongenic E16.5 eyes, bioinformatics analysis of C3H/MOLF polymorphisms, and the biological relevancy of the genes in the interval identified three genes (Cdh6, Ank and Trio) that likely contribute to the rescue of the lens phenotype. These studies demonstrate that modification of the Gpr161vl/vl cataract phenotype is likely due to genetic variants in at least one of three closely linked candidate genes on proximal Chr15.
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Mitton-Fitzgerald E, Gohr CM, Bettendorf B, Rosenthal AK. The Role of ANK in Calcium Pyrophosphate Deposition Disease. Curr Rheumatol Rep 2016; 18:25. [PMID: 27032788 DOI: 10.1007/s11926-016-0574-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The protein product of the progressive ankylosis gene, known as ANK, is a 492-amino acid multi-pass transmembrane protein. This protein is critical for the regulation of pyrophosphate, and gain of function ANK mutations is associated with calcium pyrophosphate deposition disease. Much about the structure, function, and regulation of ANK remain unstudied. This review of the current literature examines recent contributions to our understanding of ANK. We focus on new work on the function, binding partners, and regulators of ANK. A more complete understanding of this important protein may help to identify future therapeutic targets for the treatment of calcium pyrophosphate deposition disease.
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Affiliation(s)
- Elizabeth Mitton-Fitzgerald
- The Division of Rheumatology, Department of Medicine, Medical College of Wisconsin and the Zablocki VA Medical Center, Milwaukee, WI, 53295-1000, USA
| | - Claudia M Gohr
- The Division of Rheumatology, Department of Medicine, Medical College of Wisconsin and the Zablocki VA Medical Center, Milwaukee, WI, 53295-1000, USA.
| | - Brittany Bettendorf
- The Division of Rheumatology, Department of Medicine, Medical College of Wisconsin and the Zablocki VA Medical Center, Milwaukee, WI, 53295-1000, USA
| | - Ann K Rosenthal
- The Division of Rheumatology, Department of Medicine, Medical College of Wisconsin and the Zablocki VA Medical Center, Milwaukee, WI, 53295-1000, USA
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Bougault C, Briolay A, Boutet MA, Pilet P, Delplace S, Le Goff B, Guicheux J, Blanchard F, Magne D. Wnt5a is expressed in spondyloarthritis and exerts opposite effects on enthesis and bone in murine organ and cell cultures. Transl Res 2015; 166:627-38. [PMID: 26163991 DOI: 10.1016/j.trsl.2015.06.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 06/07/2015] [Accepted: 06/16/2015] [Indexed: 12/17/2022]
Abstract
Spondyloarthritis (SpA) is a chronic inflammatory joint disorder that initiates at the enthesis, where tendons attach to bone through a fibrocartilage zone. At late stages, excessive bone apposition appears within the diseased enthesis. Because Wnt5a participates to normal bone formation and appears related to inflammatory processes, we investigated the role of this Wnt growth factor in inflammation-associated ossification in SpA. The concentration of Wnt5a assessed by enzyme-linked immunosorbent assay in synovial fluids of patients with SpA (2.58 ± 0.98 ng/mL) was higher than in osteoarthritic patients (1.33 ± 0.71 ng/mL). In murine primary cultures of tendon cells, chondrocytes, and osteoblasts and in an organotypic model of mouse ankle, we showed that tumor necrosis factor α reversibly diminished Wnt5a expression and secretion, respectively. Wnt5a decreased gene expression of differentiation markers and mineralization in cultured chondrocytes and reduced alkaline phosphatase activity in Achilles tendon enthesis (-14%) and osteocalcin protein levels released by ankle explants (-36%). On the contrary, Wnt5a stimulated ossification markers' expression in cultured osteoblasts and increased the bone volume of the tibial plateau of the cultured explants (+19%). In conclusion, our results suggest that Wnt5a is expressed locally in the joints of patients with SpA. Wnt5a appears more associated with ossification than with inflammation and tends to inhibit mineralization in chondrocytes and enthesis, whereas it seems to favor the ossification process in osteoblasts and bone. Further studies are needed to decipher the opposing effects observed locally in enthesis and systemically in bone in SpA.
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Affiliation(s)
- Carole Bougault
- Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, Université Claude Bernard-Lyon 1, Université de Lyon, UMR CNRS 5246, Villeurbanne, France.
| | - Anne Briolay
- Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, Université Claude Bernard-Lyon 1, Université de Lyon, UMR CNRS 5246, Villeurbanne, France
| | - Marie-Astrid Boutet
- Physiopathologie de la Résorption Osseuse et Thérapie des Tumeurs Osseuses Primitives, Université de Nantes, INSERM, UMR957, Nantes, France
| | - Paul Pilet
- Laboratoire d'ingénierie ostéoarticulaire et dentaire, INSERM, UMRS 791, Nantes, France
| | - Séverine Delplace
- Physiopathology of Inflammatory Bone Diseases, Université du Littoral-Côte d'Opale, EA 4490, Boulogne-sur-Mer, France
| | - Benoît Le Goff
- Physiopathologie de la Résorption Osseuse et Thérapie des Tumeurs Osseuses Primitives, Université de Nantes, INSERM, UMR957, Nantes, France; Department of Rheumatology, Hôtel-Dieu, CHU de Nantes, Nantes, France
| | - Jérôme Guicheux
- Laboratoire d'ingénierie ostéoarticulaire et dentaire, INSERM, UMRS 791, Nantes, France; UFR Odontologie, Université de Nantes, Nantes, France; PHU4 OTONN, CHU de Nantes, Nantes, France
| | - Frédéric Blanchard
- Physiopathologie de la Résorption Osseuse et Thérapie des Tumeurs Osseuses Primitives, Université de Nantes, INSERM, UMR957, Nantes, France
| | - David Magne
- Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, Université Claude Bernard-Lyon 1, Université de Lyon, UMR CNRS 5246, Villeurbanne, France
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Pacheco-Tena C, Pérez-Tamayo R, Pineda C, González-Chávez SA, Quiñonez-Flores C, Ugalde Vitelly A, Inman RD, Aubin JE, Vázquez-Mellado J, Burgos-Vargas R. Bone Lineage Proteins in the Entheses of the Midfoot in Patients with Spondyloarthritis. J Rheumatol 2014; 42:630-7. [DOI: 10.3899/jrheum.140218] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2014] [Indexed: 02/02/2023]
Abstract
Objective.Patients with juvenile-onset spondyloarthritis (SpA) may develop ankylosis of the midfoot resembling the spinal changes seen in patients with ankylosing spondylitis (AS). The study of the histopathology of the feet of patients with tarsitis could help us understand the pathogenesis of bone formation in affected structures in the SpA. The objective of our study was to describe the histopathologic characteristics of the midfoot in patients with tarsitis associated with SpA.Methods.We obtained synovial sheaths, entheses, and bone samples from 20 patients with SpA with midfoot pain/tenderness and swelling. Tissue samples underwent H&E staining; immunohistochemistry for CD3, CD4, CD8, CD68, and CD20 cell identification; and immunofluorescence for bone lineage proteins, including osteocalcin, osteopontin, parathyroid hormone-related protein, bone sialoprotein, and alkaline phosphatase.Results.Slight edema and hyalinization were found in some tendon sheaths, and few inflammatory cells were detected in the entheses. In bones, we found some changes suggesting osteoproliferation, including endochondral and intramembranous ossification, but no inflammatory cells. In entheses showing bone proliferation, we detected osteocalcin and osteopontin in cells with a fibroblast-mesenchymal phenotype, suggesting the induction of entheseal cells toward an osteoblast phenotype.Conclusion.Osteoproliferation and abnormal expression of bone lineage proteins, but no inflammatory infiltration, characterize midfoot involvement in patients with SpA. In this sense, tarsitis (or ankylosing tarsitis) resembles the involvement of the spine in patients with AS. Ossification may be in part explained by the differentiation of mesenchymal entheseal cells toward the osteoblastic lineage.
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Wallis D, Inman RD. Recognition of Preclinical and Early Disease in Axial Spondyloarthritis. Rheum Dis Clin North Am 2014; 40:685-97. [DOI: 10.1016/j.rdc.2014.07.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Xu HG, Zhang W, Zheng Q, Yu YF, Deng LF, Wang H, Liu P, Zhang M. Investigating conversion of endplate chondrocytes induced by intermittent cyclic mechanical unconfined compression in three-dimensional cultures. Eur J Histochem 2014; 58:2415. [PMID: 25308847 PMCID: PMC4194395 DOI: 10.4081/ejh.2014.2415] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 06/10/2014] [Accepted: 06/12/2014] [Indexed: 12/25/2022] Open
Abstract
Mechanical stimulation is known to regulate the calcification of endplate chondrocytes. The Ank protein has a strong influence on anti-calcification by transports intracellular inorganic pyrophosphate (PPi) to the extracellular matrix. It is known that TGF-β1 is able to induce Ank gene expression and protect chondrocyte calcification. Intermittent cyclic mechanical tension (ICMT) could induce calcification of endplate chondrocytes by decrease the expression of Ank gene. In this study, we investigated the relation of intermittent cyclic mechanical unconfined compression (ICMC) and Ank gene expression. We found that ICMC decreased the Ank gene expression in the endplate chondrocytes, and there was an decreased in the TGF-β1 expression after ICMC stimulation. The Ank gene expression significantly increased when treated by transforming growth factor alpha 1 (TGF-β1) in a dose-dependent manner and decreased when treated by SB431542 (ALK inhibitor) in a dose-dependent manner. Our results implicate that ICMC-induced downregulation of Ank gene expression may be regulated by TGF-β1 in end-plate chondrocytes.
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The effect of tumor necrosis factor-blockade on new bone formation in ankylosing spondylitis. Curr Opin Rheumatol 2014; 26:389-94. [DOI: 10.1097/bor.0000000000000077] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Tsui FW, Tsui HW, Akram A, Haroon N, Inman RD. The genetic basis of ankylosing spondylitis: new insights into disease pathogenesis. APPLICATION OF CLINICAL GENETICS 2014; 7:105-15. [PMID: 24971029 PMCID: PMC4070859 DOI: 10.2147/tacg.s37325] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ankylosing spondylitis (AS) is a complex disease involving multiple risk factors, both genetic and environmental. AS patients are predominantly young men, and the disease is characterized by inflammation and ankylosis, mainly at the cartilage–bone interface and enthesis. HLA-B27 has been known to be the major AS-susceptibility gene for more than 40 years. Despite advances made in the past few years, progress in the search for non-human leukocyte antigen susceptibility genes has been hampered by the heterogeneity of the disease. Compared to other complex diseases, such as inflammatory bowel disease (IBD), fewer susceptibility loci have been identified in AS. Furthermore, non-major histocompatibility-complex susceptibility loci discovered, such as ERAP1 and IL23R, are likely contributors to joint inflammation. Identification and confirmation of functional variants remains a significant challenge of investigations involving genome-wide association studies (GWAS). It remains unclear why none of the AS-susceptibility genes identified in GWAS appear to be directly involved in the ankylosing process. Numerous reviews have recently been published on the genetics of AS. Therefore, aside from a brief summary of what AS GWAS has successfully achieved thus far, this review will focus on directions that could address unanswered questions raised by GWAS.
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Affiliation(s)
- Florence Wl Tsui
- Genetics and Development Division, Toronto Western Research Institute, University Health Network ; Department of Immunology
| | - Hing Wo Tsui
- Genetics and Development Division, Toronto Western Research Institute, University Health Network
| | - Ali Akram
- Genetics and Development Division, Toronto Western Research Institute, University Health Network ; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Nigil Haroon
- Genetics and Development Division, Toronto Western Research Institute, University Health Network ; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Robert D Inman
- Genetics and Development Division, Toronto Western Research Institute, University Health Network ; Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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Tsui FWL, Tsui HW, Las Heras F, Pritzker KPH, Inman RD. Serum levels of novel noggin and sclerostin-immune complexes are elevated in ankylosing spondylitis. Ann Rheum Dis 2013; 73:1873-9. [PMID: 23894062 DOI: 10.1136/annrheumdis-2013-203630] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Unravelling the basis of joint inflammation and ankylosis represents a major challenge in ankylosing spondylitis (AS) research. As noggin (NOG) and sclerostin (SOST) have recently been associated with the disease process in mouse and human studies, respectively, we explored the immune responses to these two molecules in AS. METHODS Immune complexes (IC) composed of IgG autoantibodies to NOG and SOST were detected by immunoprecipitation and Western blot analyses. Epitope-specific IgG were measured using peptide-binding ELISA. Serum samples were obtained from healthy controls and patients with AS, mechanical back pain (MBP) and inflammatory bowel disease (IBD) with or without concomitant AS. RESULTS NOG and SOST-IgG IC were present in NOG-treated and untreated ank/ank (progressive ankylosis), but not in wild-type mice. Higher than normal levels of NOG and SOST-IgG IC are present in AS sera (p<0.001). We showed a SOST peptide (SOST-S146, with homology to a bacterial glycotransferase peptide) binds to a NOG peptide (NOG-N54), which contains a N-glycosylation site. AS patients have higher levels of IgG recognising the NOG-N54 and SOST-S146 peptides compared to the levels in normal controls, IBD and MBP patients (one way analysis of variance p<0.0001). CONCLUSIONS This is the first report showing IgG autoantibodies to NOG and SOST in normal individuals, and higher levels of NOG and/or SOST-IgG IC probably contribute to neo-ossification in AS patients. These novel findings hold the promise of earlier diagnosis, better management of AS with comorbidities and new therapeutic approaches to modulate ankylosis in AS.
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Affiliation(s)
- Florence W L Tsui
- Genetics and Development Division, TorontoWestern Research Institute, University Health Network, Toronto, Ontario, Canada Departments of Immunology and Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Hing Wo Tsui
- Genetics and Development Division, TorontoWestern Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Facundo Las Heras
- Department of Anatomical Pathology, University of Chile Clinical Hospital, Santiago, Chile
| | - Kenneth P H Pritzker
- Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Robert D Inman
- Genetics and Development Division, TorontoWestern Research Institute, University Health Network, Toronto, Ontario, Canada Departments of Immunology and Medicine, University of Toronto, Toronto, Ontario, Canada
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