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Cui X, Wang F, Liu C. A review of TSHR- and IGF-1R-related pathogenesis and treatment of Graves' orbitopathy. Front Immunol 2023; 14:1062045. [PMID: 36742308 PMCID: PMC9893276 DOI: 10.3389/fimmu.2023.1062045] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 01/02/2023] [Indexed: 01/20/2023] Open
Abstract
Graves' orbitopathy (GO) is an organ-specific autoimmune disease, but its pathogenesis remains unclear. There are few review articles on GO research from the perspective of target cells and target antigens. A systematic search of PubMed was performed, focusing mainly on studies published after 2015 that involve the role of target cells, orbital fibroblasts (OFs) and orbital adipocytes (OAs), target antigens, thyrotropin receptor (TSHR) and insulin-like growth factor-1 receptor (IGF-1R), and their corresponding antibodies, TSHR antibodies (TRAbs) and IGF-1R antibodies (IGF-1R Abs), in GO pathogenesis and the potentially effective therapies that target TSHR and IGF-1R. Based on the results, OFs may be derived from bone marrow-derived CD34+ fibrocytes. In addition to CD34+ OFs, CD34- OFs are important in the pathogenesis of GO and may be involved in hyaluronan formation. CD34- OFs expressing Slit2 suppress the phenotype of CD34+ OFs. β-arrestin 1 can be involved in TSHR/IGF-1R crosstalk as a scaffold. Research on TRAbs has gradually shifted to TSAbs, TBAbs and the titre of TRAbs. However, the existence and role of IGF-1R Abs are still unknown and deserve further study. Basic and clinical trials of TSHR-inhibiting therapies are increasing, and TSHR is an expected therapeutic target. Teprotumumab has become the latest second-line treatment for GO. This review aims to effectively describe the pathogenesis of GO from the perspective of target cells and target antigens and provide ideas for its fundamental treatment.
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Affiliation(s)
- Xuejiao Cui
- Department of Endocrinology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Futao Wang
- Department of Endocrinology, Changchun Central Hospital, Changchun, China
| | - Cong Liu
- Department of Endocrinology, Shengjing Hospital of China Medical University, Shenyang, China
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Girnita L, Smith TJ, Janssen JAMJL. It Takes Two to Tango: IGF-I and TSH Receptors in Thyroid Eye Disease. J Clin Endocrinol Metab 2022; 107:S1-S12. [PMID: 35167695 PMCID: PMC9359450 DOI: 10.1210/clinem/dgac045] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Indexed: 12/13/2022]
Abstract
CONTEXT Thyroid eye disease (TED) is a complex autoimmune disease process. Orbital fibroblasts represent the central orbital immune target. Involvement of the TSH receptor (TSHR) in TED is not fully understood. IGF-I receptor (IGF-IR) is overexpressed in several cell types in TED, including fibrocytes and orbital fibroblasts. IGF-IR may form a physical and functional complex with TSHR. OBJECTIVE Review literature relevant to autoantibody generation in TED and whether these induce orbital fibroblast responses directly through TSHR, IGF-IR, or both. EVIDENCE IGF-IR has traditionally been considered a typical tyrosine kinase receptor in which tyrosine residues become phosphorylated following IGF-I binding. Evidence has emerged that IGF-IR possesses kinase-independent activities and can be considered a functional receptor tyrosine kinase/G-protein-coupled receptor hybrid, using the G-protein receptor kinase/β-arrestin system. Teprotumumab, a monoclonal IGF-IR antibody, effectively reduces TED disease activity, proptosis, and diplopia. In addition, the drug attenuates in vitro actions of both IGF-I and TSH in fibrocytes and orbital fibroblasts, including induction of proinflammatory cytokines by TSH and TED IgGs. CONCLUSIONS Although teprotumumab has been proven effective and relatively safe in the treatment of TED, many questions remain pertaining to IGF-IR, its relationship with TSHR, and how the drug might be disrupting these receptor protein/protein interactions. Here, we propose 4 possible IGF-IR activation models that could underlie clinical responses to teprotumumab observed in patients with TED. Teprotumumab is associated with several adverse events, including hyperglycemia and hearing abnormalities. Underpinning mechanisms of these are being investigated. Patients undergoing treatment with drug must be monitored for these and managed with best medical practices.
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Affiliation(s)
- Leonard Girnita
- Department of Oncology and Pathology, BioClinicum, Karolinska Institutet and Karolinska University Hospital, 17164 Stockholm, Sweden
| | - Terry J Smith
- Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, MI 48105, USA
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Joseph A M J L Janssen
- Correspondence: Joseph A.M.J.L. Janssen, MD, PhD, Erasmus Medical Centre, Erasmus MC, Molewaterplein 40, 3015 GD Rotterdam, Netherlands.
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Kim BR, Kim J, Lee JE, Lee EJ, Yoon JS. Therapeutic Effect of Guggulsterone in Primary Cultured Orbital Fibroblasts Obtained From Patients with Graves' Orbitopathy. Invest Ophthalmol Vis Sci 2020; 61:39. [PMID: 32196098 PMCID: PMC7401490 DOI: 10.1167/iovs.61.3.39] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Purpose Inflammation, hyaluronan production, and adipogenesis are the main pathological events leading to Graves' orbitopathy (GO). Guggulsterone (GS), a phytosterol found in the resin of the guggul plant, is a well-known treatment for several inflammatory disorders, such as arthritis, obesity, and hyperlipidemia. Here we investigated the effects of GS treatment on GO pathology. Methods Using primary cultures of orbital fibroblasts from GO patients and non-GO controls, we examined the effects of GS on hyaluronan production and the production of proinflammatory cytokines induced by interleukin (IL)-1β, using real-time reverse transcription-polymerase chain reaction analysis, western blots, and enzyme-linked immunosorbent assays. Further, adipogenic differentiation was evaluated by quantification of Oil Red O staining and assessment of protein levels of peroxisome proliferator activator gamma (PPARγ), CCAAT-enhancer-binding proteins (C/EBP) α and β, and sterol regulatory element-binding protein-1 (SREBP-1). Results Treatment with noncytotoxic concentrations of GS resulted in the dose-dependent inhibition of IL-1β-induced inflammatory cytokines, including IL-6, IL-8, MCP-1, and COX-2, at both mRNA and protein levels. The hyaluronan level was also significantly suppressed by GS. Moreover, GS significantly decreased the formation of lipid droplets and expression of PPARγ, C/EBP α/β, and SREBP-1 in a dose-dependent manner. GS pretreatment attenuated the phosphorylation of nuclear factor-kappa B induced by IL-1β. Conclusions Our data show significant inhibitory effects of GS on inflammation, production of hyaluronan, and adipogenesis in orbital fibroblasts. To our knowledge, this is the first in vitro preclinical evidence of the therapeutic effect of GS in GO.
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Immunological Aspects of Graves' Ophthalmopathy. BIOMED RESEARCH INTERNATIONAL 2019; 2019:7453260. [PMID: 31781640 PMCID: PMC6875285 DOI: 10.1155/2019/7453260] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 08/30/2019] [Indexed: 12/13/2022]
Abstract
The body's autoimmune process is involved in the development of Graves' disease (GD), which is manifested by an overactive thyroid gland. In some patients, autoreactive inflammatory reactions contribute to the development of symptoms such as thyroid ophthalmopathy, and the subsequent signs and symptoms are derived from the expansion of orbital adipose tissue and edema of extraocular muscles within the orbit. The autoimmune process, production of antibodies against self-antigens such as TSH receptor (TSHR) and IGF-1 receptor (IGF-1R), inflammatory infiltration, and accumulation of glycosaminoglycans (GAG) lead to edematous-infiltrative changes in periocular tissues. As a consequence, edema exophthalmos develops. Orbital fibroblasts seem to play a crucial role in orbital inflammation, tissue expansion, remodeling, and fibrosis because of their proliferative activity as well as their capacity to differentiate into adipocytes and myofibroblasts and production of GAG. In this paper, based on the available medical literature, the immunological mechanism of GO pathogenesis has been summarized. Particular attention was paid to the role of orbital fibroblasts and putative autoantigens. A deeper understanding of the pathomechanism of the disease and the involvement of immunological processes may give rise to the introduction of new, effective, and safe methods of treatment or monitoring of the disease activity.
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Wang ZM, Wang ZY, Lu Y. The role of cell mediated immunopathogenesis in thyroid-associated ophthalmopathy. Int J Ophthalmol 2019; 12:1209-1214. [PMID: 31341815 DOI: 10.18240/ijo.2019.07.24] [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: 01/03/2019] [Accepted: 05/21/2019] [Indexed: 12/31/2022] Open
Abstract
Currently, thyroid-associated ophthalmopathy (TAO) lacks effective treatment due to our lack of clarity in its immunopathogenesis. Orbital fibroblasts play a key role in altering inflammation and immune response in TAO, and are considered as the key target and effector cells in its pathogenesis. The orbit infiltrating CD34+ fibrocytes add on to the process by expressing high levels of autoantigens and inflammatory cytokines, while also differentiating into myofibroblasts or adipocytes. This review focuses on the role of orbital fibroblasts and CD34+ fibrocytes in the pathogenesis of TAO, highlighting the basis of emerging treatments.
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Affiliation(s)
- Zhen-Mao Wang
- Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong, Shantou 515000, Guangdong Province, China
| | - Zheng-Yan Wang
- The People's Hospital of Xintai, Xintai 271200, Shandong Province, China
| | - Yan Lu
- Department of Ophthalmology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, Jiangsu Province, China
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Kotwal A, Turcu AF, Sonawane V, Bahn RS, Pittelkow MR, Bridges A, Stan MN. Clinical Experience with Rituximab and Intravenous Immunoglobulin for Pretibial Myxedema: A Case Series. Thyroid 2019; 29:692-699. [PMID: 30854936 DOI: 10.1089/thy.2018.0706] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Background: Severe pretibial myxedema (PTM) can be difficult to manage, highlighting the need to investigate newer therapies. Rituximab (RTX) and intravenous immunoglobulin (IVIg) have been tried in Graves' orbitopathy. Since PTM and orbitopathy share a similar underlying pathophysiology, this study aimed to explore these therapies for progressive PTM. Methods: The electronic database was screened for PTM patients evaluated at the Mayo Clinic, Rochester, from 2002 to 2016, and three patients who received IVIg and five who received RTX are reported. PTM pattern was classified as non-pitting edema, plaque and induration, nodular/nummular, and elephantiasis. PTM was confirmed by biopsy in six patients. Results: The patients' median age was 53.8 years, 75% were female, and all but one patient were either active or former smokers. All patients were euthyroid and had progressed despite various therapies prior to starting these agents. Six patients had a plaque and induration pattern, and two had a nodular pattern with elephantiasis. After therapy, six (75%) patients had PTM stability or improvement both subjectively and objectively (80% with RTX and 66% with IVIg). The three patients (one in the IVIg group and two in the RTX group) who had subjective improvement had a plaque pattern. One patient with elephantiasis had a transient response to IVIg and another had stability after RTX. Thyrotropin receptor antibody values and orbitopathy also improved in patients who demonstrated PTM improvement. No serious adverse events were reported, but one patient each had transient hypertension and injection-site thrombophlebitis after IVIg. Conclusions: Immunomodulation therapy was followed by PTM improvement or stability in most patients, with a slightly better response after RTX compared to IVIg. A validated response assessment instrument and larger series of patients are required to determine if the underlying disease process could be curtailed with these agents.
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Affiliation(s)
- Anupam Kotwal
- 1 Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Adina F Turcu
- 2 Division of Metabolism, Endocrinology, and Diabetes, University of Michigan, Ann Arbor, Michigan
| | - Vikram Sonawane
- 1 Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Rebecca S Bahn
- 1 Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | | | - Alina Bridges
- 3 Department of Dermatology, Mayo Clinic, Rochester, Minnesota
- 4 Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Marius N Stan
- 1 Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
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Abstract
PURPOSE Thyroid autoimmunity affects approximately 5% of the population, and its investigation relies heavily on the use of autoantibodies. Thyroid stimulating hormone receptor (TSHR) autoantibodies (TRAb) play a central role in the evaluation of Graves disease (GD), Graves ophthalmopathy (GO) and pretibial myxedema (PTM). However, there is still controversy regarding overall TRAb assay diagnostic accuracy and their prognostic utility. METHODS We reviewed and analyzed the literature reporting TRAb assays and their clinical utility. RESULTS Current assays measure the overall TRAb titer in a competitive manner (TSH binding inhibiting immunoglobulin assay) or biologic activity of the stimulating TSHR autoantibodies (thyroid stimulating immunoglobulin assay). Both types of assays have improved over time with advances in sensitivity and specificity. TRAb are particularly relevant in hyperthyroidism cases where use of iodinated contrast is not an option (e.g., pregnancy or recent use of iodinated contrast) or in cases of euthyroid eye disease, suspicious for GO. Third generation TRAb assays are useful for therapy selection in GD, prognostic predictions in GO and risk prediction for fetal and neonatal thyrotoxicosis. DISCUSSION Given the pathogenic role of TRAb, we expect that the future will bring useful evidence regarding their predictive role with respect to efficacy of therapeutic modalities for GO and PTM. We also hope to better understand the role of blocking and neutral antibodies against TSHR, and harness that ability for modulation of thyroid function or therapy of differentiated thyroid carcinoma managed with TSH suppression. CONCLUSIONS Thyroid autoimmune diseases have seen tremendous gains in understanding their pathophysiology, largely antibody mediated. Better TRAb testing is becoming a springboard for providing individualized patient care.
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Moleti M, Sturniolo G, Vermiglio F. Safety of total thyroid ablation in patients with Graves' orbitopathy. J Endocrinol Invest 2016; 39:1199-201. [PMID: 27206633 DOI: 10.1007/s40618-016-0485-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 05/09/2016] [Indexed: 10/21/2022]
Affiliation(s)
- M Moleti
- Dipartimento di Medicina Clinica e Sperimentale, University of Messina, Messina, Italy
| | - G Sturniolo
- Dipartimento di Medicina Clinica e Sperimentale, University of Messina, Messina, Italy
- Dipartimento di Patologia Umana dell'adulto e dell'età evolutiva "Gaetano Barresi", University of Messina, Via Consolare Valeria 1, 98125, Messina, Italy
| | - F Vermiglio
- Dipartimento di Medicina Clinica e Sperimentale, University of Messina, Messina, Italy.
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Krieger CC, Place RF, Bevilacqua C, Marcus-Samuels B, Abel BS, Skarulis MC, Kahaly GJ, Neumann S, Gershengorn MC. TSH/IGF-1 Receptor Cross Talk in Graves' Ophthalmopathy Pathogenesis. J Clin Endocrinol Metab 2016; 101:2340-7. [PMID: 27043163 PMCID: PMC4891793 DOI: 10.1210/jc.2016-1315] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
CONTEXT The TSH receptor (TSHR) is considered the main target of stimulatory autoantibodies in the pathogenesis of Graves' ophthalmopathy (GO); however, it has been suggested that stimulatory IGF-1 receptor (IGF-1R) autoantibodies also play a role. OBJECTIVE We previously demonstrated that a monoclonal stimulatory TSHR antibody, M22, activates TSHR/IGF-1R cross talk in orbital fibroblasts/preadipocytes obtained from patients with GO (GO fibroblasts [GOFs]). We show that cross talk between TSHR and IGF-1R, not direct IGF-1R activation, is involved in the mediation of GO pathogenesis stimulated by Graves' autoantibodies. DESIGN/SETTING/PARTICIPANTS Immunoglobulins were purified from the sera of 57 GO patients (GO-Igs) and tested for their ability to activate TSHR and/or IGF-1R directly and TSHR/IGF-1R cross talk in primary cultures of GOFs. Cells were treated with M22 or GO-Igs with or without IGF-1R inhibitory antibodies or linsitinib, an IGF-1R kinase inhibitor. MAIN OUTCOME MEASURES Hyaluronan (hyaluronic acid [HA]) secretion was measured as a major biological response for GOF stimulation. IGF-1R autophosphorylation was used as a measure of direct IGF-1R activation. TSHR activation was determined through cAMP production. RESULTS A total of 42 out of 57 GO-Ig samples stimulated HA secretion. None of the GO-Ig samples exhibited evidence for IGF-1R autophosphorylation. Both anti-IGF-1R antibodies completely inhibited IGF-1 stimulation of HA secretion. By contrast, only 1 IGF-1R antibody partially blocked HA secretion stimulated by M22 or GO-Igs in a manner similar to linsitinib, whereas the other IGF-1R antibody had no effect on M22 or GO-Ig stimulation. These findings show that the IGF-1R is involved in GO-Igs stimulation of HA secretion without direct activation of IGF-1R. CONCLUSIONS IGF-1R activation by GO-Igs occurs via TSHR/IGF-1R cross talk rather than direct binding to IGF-1R, and this cross talk is important in the pathogenesis of GO.
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Affiliation(s)
- Christine C Krieger
- Laboratory of Endocrinology and Receptor Biology (C.C.K., R.F.P., C.B., B.M.-S., S.N., M.C.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Nova Therapeutics LLC (R.F.P.), Pasadena, California; Diabetes, Endocrinology, and Obesity Branch (B.S.A., M.C.S.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; and Johannes Gutenberg University Medical Center (G.J.K.), Mainz, Germany
| | - Robert F Place
- Laboratory of Endocrinology and Receptor Biology (C.C.K., R.F.P., C.B., B.M.-S., S.N., M.C.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Nova Therapeutics LLC (R.F.P.), Pasadena, California; Diabetes, Endocrinology, and Obesity Branch (B.S.A., M.C.S.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; and Johannes Gutenberg University Medical Center (G.J.K.), Mainz, Germany
| | - Carmine Bevilacqua
- Laboratory of Endocrinology and Receptor Biology (C.C.K., R.F.P., C.B., B.M.-S., S.N., M.C.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Nova Therapeutics LLC (R.F.P.), Pasadena, California; Diabetes, Endocrinology, and Obesity Branch (B.S.A., M.C.S.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; and Johannes Gutenberg University Medical Center (G.J.K.), Mainz, Germany
| | - Bernice Marcus-Samuels
- Laboratory of Endocrinology and Receptor Biology (C.C.K., R.F.P., C.B., B.M.-S., S.N., M.C.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Nova Therapeutics LLC (R.F.P.), Pasadena, California; Diabetes, Endocrinology, and Obesity Branch (B.S.A., M.C.S.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; and Johannes Gutenberg University Medical Center (G.J.K.), Mainz, Germany
| | - Brent S Abel
- Laboratory of Endocrinology and Receptor Biology (C.C.K., R.F.P., C.B., B.M.-S., S.N., M.C.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Nova Therapeutics LLC (R.F.P.), Pasadena, California; Diabetes, Endocrinology, and Obesity Branch (B.S.A., M.C.S.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; and Johannes Gutenberg University Medical Center (G.J.K.), Mainz, Germany
| | - Monica C Skarulis
- Laboratory of Endocrinology and Receptor Biology (C.C.K., R.F.P., C.B., B.M.-S., S.N., M.C.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Nova Therapeutics LLC (R.F.P.), Pasadena, California; Diabetes, Endocrinology, and Obesity Branch (B.S.A., M.C.S.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; and Johannes Gutenberg University Medical Center (G.J.K.), Mainz, Germany
| | - George J Kahaly
- Laboratory of Endocrinology and Receptor Biology (C.C.K., R.F.P., C.B., B.M.-S., S.N., M.C.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Nova Therapeutics LLC (R.F.P.), Pasadena, California; Diabetes, Endocrinology, and Obesity Branch (B.S.A., M.C.S.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; and Johannes Gutenberg University Medical Center (G.J.K.), Mainz, Germany
| | - Susanne Neumann
- Laboratory of Endocrinology and Receptor Biology (C.C.K., R.F.P., C.B., B.M.-S., S.N., M.C.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Nova Therapeutics LLC (R.F.P.), Pasadena, California; Diabetes, Endocrinology, and Obesity Branch (B.S.A., M.C.S.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; and Johannes Gutenberg University Medical Center (G.J.K.), Mainz, Germany
| | - Marvin C Gershengorn
- Laboratory of Endocrinology and Receptor Biology (C.C.K., R.F.P., C.B., B.M.-S., S.N., M.C.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; Nova Therapeutics LLC (R.F.P.), Pasadena, California; Diabetes, Endocrinology, and Obesity Branch (B.S.A., M.C.S.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892; and Johannes Gutenberg University Medical Center (G.J.K.), Mainz, Germany
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Smith TJ, Janssen JAMJL. Building the Case for Insulin-Like Growth Factor Receptor-I Involvement in Thyroid-Associated Ophthalmopathy. Front Endocrinol (Lausanne) 2016; 7:167. [PMID: 28096798 PMCID: PMC5206614 DOI: 10.3389/fendo.2016.00167] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 12/13/2016] [Indexed: 11/18/2022] Open
Abstract
The pathogenesis of orbital Graves' disease (GD), a process known as thyroid-associated ophthalmopathy (TAO), remains incompletely understood. The thyrotropin receptor (TSHR) represents the central autoantigen involved in GD and has been proposed as the thyroid antigen shared with the orbit that could explain the infiltration of immune cells into tissues surrounding the eye. Another cell surface protein, insulin-like growth factor-I receptor (IGF-IR), has recently been proposed as a second antigen that participates in TAO by virtue of its interactions with anti-IGF-IR antibodies generated in GD, its apparent physical and functional complex formation with TSHR, and its necessary involvement in TSHR post-receptor signaling. The proposal that IGF-IR is involved in TAO has provoked substantial debate. Furthermore, several studies from different laboratory groups, each using different experimental models, have yielded conflicting results. In this article, we attempt to summarize the biological characteristics of IGF-IR and TSHR. We also review the evidence supporting and refuting the postulate that IGF-IR is a self-antigen in GD and that it plays a potentially important role in TAO. The putative involvement of IGF-IR in disease pathogenesis carries substantial clinical implications. Specifically, blocking this receptor with monoclonal antibodies can dramatically attenuate the induction by TSH and pathogenic antibodies generated in GD of proinflammatory genes in cultured orbital fibroblasts and fibrocytes. These cell types appear critical to the development of TAO. These observations have led to the conduct of a now-completed multicenter therapeutic trial of a fully human monoclonal anti-IGF-IR blocking antibody in moderate to severe, active TAO.
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Affiliation(s)
- Terry J. Smith
- Department of Ophthalmology and Visual Sciences, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
- *Correspondence: Terry J. Smith,
| | - Joseph A. M. J. L. Janssen
- Department of Internal Medicine, Erasmus Medical Center, Division of Endocrinology, Rotterdam, Netherlands
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Le Moli R, Muscia V, Tumminia A, Frittitta L, Buscema M, Palermo F, Sciacca L, Squatrito S, Vigneri R. Type 2 diabetic patients with Graves' disease have more frequent and severe Graves' orbitopathy. Nutr Metab Cardiovasc Dis 2015; 25:452-457. [PMID: 25746910 DOI: 10.1016/j.numecd.2015.01.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 01/09/2015] [Accepted: 01/18/2015] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND AIMS Due to the worldwide increasing prevalence of diabetes (DM), patients with both diabetes and Graves' disease (GD) have become more frequent. Sporadic reports indicate that Graves' orbitopathy (GO), a GD complication that affects orbital soft tissues, can be severe in DM patients. The relationship between these diseases is not well understood. This study aims at evaluating the association of GD and GO with autoimmune and non-autoimmune diabetes (DM) and to assess diabetic features that influence GD and GO prevalence and severity. METHODS AND RESULTS This retrospective study evaluated GD, GO and DM association in 1211 consecutive GD patients (447 with GO and 77 with DM). A case-control study was carried out to evaluate DM relationship with GO severity by comparing at 1:2 ratio GO patients with or without DM. A strong association was found between GD and T1DM (p = 0.01) but not T2DM. Instead, the presence of GO was strongly associated with T2DM (p = 0.01). Moreover, GO was more frequently severe in GD patients with T2DM (11/30 or 36.6%) than in those without T2DM (1/60 or 1.7%, p = 0.05). T2DM was the strongest risk factor for severe GO (OR = 34.1 vs. 4.4 p < 0.049 in cigarette smokers). DM duration, obesity and vascular complications, but not metabolic control were significant determinants of GO severity. CONCLUSIONS GD is associated with T1DM but not with T2DM, probably because of the common autoimmune background. GO, in contrast, is more frequent and severe in T2DM, significantly associated with obesity, diabetes duration and diabetic vasculopathy but not metabolic control.
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Affiliation(s)
- R Le Moli
- Department of Clinical and Molecular Biomedicine, Endocrinology Unit, Garibaldi-Nesima Medical Center, University of Catania, Via Palermo 636, 95100 Catania, Italy.
| | - V Muscia
- Department of Clinical and Molecular Biomedicine, Endocrinology Unit, Garibaldi-Nesima Medical Center, University of Catania, Via Palermo 636, 95100 Catania, Italy
| | - A Tumminia
- Department of Clinical and Molecular Biomedicine, Endocrinology Unit, Garibaldi-Nesima Medical Center, University of Catania, Via Palermo 636, 95100 Catania, Italy
| | - L Frittitta
- Department of Clinical and Molecular Biomedicine, Endocrinology Unit, Garibaldi-Nesima Medical Center, University of Catania, Via Palermo 636, 95100 Catania, Italy
| | - M Buscema
- Department of Clinical and Molecular Biomedicine, Endocrinology Unit, Garibaldi-Nesima Medical Center, University of Catania, Via Palermo 636, 95100 Catania, Italy
| | - F Palermo
- Department of Clinical and Molecular Biomedicine, Endocrinology Unit, Garibaldi-Nesima Medical Center, University of Catania, Via Palermo 636, 95100 Catania, Italy
| | - L Sciacca
- Department of Clinical and Molecular Biomedicine, Endocrinology Unit, Garibaldi-Nesima Medical Center, University of Catania, Via Palermo 636, 95100 Catania, Italy
| | - S Squatrito
- Department of Clinical and Molecular Biomedicine, Endocrinology Unit, Garibaldi-Nesima Medical Center, University of Catania, Via Palermo 636, 95100 Catania, Italy
| | - R Vigneri
- Department of Clinical and Molecular Biomedicine, Endocrinology Unit, Garibaldi-Nesima Medical Center, University of Catania, Via Palermo 636, 95100 Catania, Italy; National Research Council (CNR), Department of Biostructures and Bioimmaging, Catania, Italy
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Siiskonen H, Oikari S, Pasonen-Seppänen S, Rilla K. Hyaluronan synthase 1: a mysterious enzyme with unexpected functions. Front Immunol 2015; 6:43. [PMID: 25699059 PMCID: PMC4318391 DOI: 10.3389/fimmu.2015.00043] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 01/22/2015] [Indexed: 11/13/2022] Open
Abstract
Hyaluronan synthase 1 (HAS1) is one of three isoenzymes responsible for cellular hyaluronan synthesis. Interest in HAS1 has been limited because its role in hyaluronan production seems to be insignificant compared to the two other isoenzymes, HAS2 and HAS3, which have higher enzymatic activity. Furthermore, in most cell types studied so far, the expression of its gene is low and the enzyme requires high concentrations of sugar precursors for hyaluronan synthesis, even when overexpressed in cell cultures. Both expression and activity of HAS1 are induced by pro-inflammatory factors like interleukins and cytokines, suggesting its involvement in inflammatory conditions. Has1 is upregulated in states associated with inflammation, like atherosclerosis, osteoarthritis, and infectious lung disease. In addition, both full length and splice variants of HAS1 are expressed in malignancies like bladder and prostate cancers, multiple myeloma, and malignant mesothelioma. Interestingly, immunostainings of tissue sections have demonstrated the role of HAS1 as a poor predictor in breast cancer, and is correlated with high relapse rate and short overall survival. Utilization of fluorescently tagged proteins has revealed the intracellular distribution pattern of HAS1, distinct from other isoenzymes. In all cell types studied so far, a high proportion of HAS1 is accumulated intracellularly, with a faint signal detected on the plasma membrane and its protrusions. Furthermore, the pericellular hyaluronan coat produced by HAS1 is usually thin without induction by inflammatory agents or glycemic stress and depends on CD44–HA interactions. These specific interactions regulate the organization of hyaluronan into a leukocyte recruiting matrix during inflammatory responses. Despite the apparently minor enzymatic activity of HAS1 under normal conditions, it may be an important factor under conditions associated with glycemic stress like metabolic syndrome, inflammation, and cancer.
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Affiliation(s)
- Hanna Siiskonen
- Department of Dermatology, Kuopio University Hospital, University of Eastern Finland , Kuopio , Finland
| | - Sanna Oikari
- Institute of Biomedicine, University of Eastern Finland , Kuopio , Finland
| | | | - Kirsi Rilla
- Institute of Biomedicine, University of Eastern Finland , Kuopio , Finland
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14
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Krieger CC, Gershengorn MC. A modified ELISA accurately measures secretion of high molecular weight hyaluronan (HA) by Graves' disease orbital cells. Endocrinology 2014; 155:627-34. [PMID: 24302624 PMCID: PMC3891933 DOI: 10.1210/en.2013-1890] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Excess production of hyaluronan (hyaluronic acid [HA]) in the retro-orbital space is a major component of Graves' ophthalmopathy, and regulation of HA production by orbital cells is a major research area. In most previous studies, HA was measured by ELISAs that used HA-binding proteins for detection and rooster comb HA as standards. We show that the binding efficiency of HA-binding protein in the ELISA is a function of HA polymer size. Using gel electrophoresis, we show that HA secreted from orbital cells is primarily comprised of polymers more than 500 000. We modified a commercially available ELISA by using 1 million molecular weight HA as standard to accurately measure HA of this size. We demonstrated that IL-1β-stimulated HA secretion is at least 2-fold greater than previously reported, and activation of the TSH receptor by an activating antibody M22 from a patient with Graves' disease led to more than 3-fold increase in HA production in both fibroblasts/preadipocytes and adipocytes. These effects were not consistently detected with the commercial ELISA using rooster comb HA as standard and suggest that fibroblasts/preadipocytes may play a more prominent role in HA remodeling in Graves' ophthalmopathy than previously appreciated.
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Affiliation(s)
- Christine C Krieger
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892
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15
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Oh SR, Priel A, Granet DB, Levi L, Korn BS, Kikkawa DO. Thyroid-related orbitopathy: a multidisciplinary perspective. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.10.81] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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16
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Hyaluronan synthase 1 (HAS1) produces a cytokine-and glucose-inducible, CD44-dependent cell surface coat. Exp Cell Res 2014; 320:153-63. [DOI: 10.1016/j.yexcr.2013.09.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 09/23/2013] [Accepted: 09/28/2013] [Indexed: 02/04/2023]
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17
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Turcu AF, Kumar S, Neumann S, Coenen M, Iyer S, Chiriboga P, Gershengorn MC, Bahn RS. A small molecule antagonist inhibits thyrotropin receptor antibody-induced orbital fibroblast functions involved in the pathogenesis of Graves ophthalmopathy. J Clin Endocrinol Metab 2013; 98:2153-9. [PMID: 23482611 PMCID: PMC3644605 DOI: 10.1210/jc.2013-1149] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Graves ophthalmopathy (GO) is an autoimmune disorder characterized by increased adipogenesis and hyaluronan (HA) production by orbital fibroblasts. Circulating autoantibodies (thyroid-stimulating antibodies [TSAbs]) directed at the thyrotropin receptor (TSHR) on these cells stimulate or augment these cellular processes. A recently developed drug-like small molecule inverse agonist of TSHR, NCGC00229600, termed 1, binds to TSHR and blocks basal and stimulated signal transduction. OBJECTIVE The purpose of this article was to determine whether 1 might inhibit HA production and relevant signaling pathways in orbital fibroblasts cultured in the presence of monoclonal TSAbs or bovine TSH (bTSH). DESIGN Primary cultures of undifferentiated GO orbital fibroblasts (n = 13) were untreated or treated with a TSAb (M22 or MS-1) or bTSH in serum-free medium, with or without 1 or a TSHR neutral antagonist, NCGC00242595, termed 2, which does not inhibit basal signaling but does inhibit stimulated signaling. MAIN OUTCOME MEASURES cAMP production, Akt phosphorylation (Ser473pAkt in media and immunoblotting for pAkt/total Akt), and HA production were analyzed. RESULTS Compound 1 inhibited basal cAMP, pAkt, and HA production and that stimulated by M22 in undifferentiated orbital fibroblasts. Inhibition of HA production was dose-dependent, with a half-maximal inhibitory dose of 830 nM. This compound also inhibited MS-1- and bTSH-stimulated cAMP, pAkt, and HA production. Compound 2 did not inhibit basal HA production but did inhibit M22-stimulated HA production. CONCLUSIONS Because cAMP, pAkt, and HA production are fibroblast functions that are activated via TSHR signaling and are important in the pathogenesis of GO, small molecule TSHR antagonists may prove to be effective in the treatment or prevention of the disease in the future.
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MESH Headings
- Adipose Tissue, White/drug effects
- Adipose Tissue, White/immunology
- Adipose Tissue, White/metabolism
- Adipose Tissue, White/pathology
- Antibodies, Monoclonal/metabolism
- Cell Dedifferentiation
- Cells, Cultured
- Cyclic AMP/metabolism
- Drug Inverse Agonism
- Eye/drug effects
- Eye/immunology
- Eye/metabolism
- Eye/pathology
- Fibroblasts/drug effects
- Fibroblasts/immunology
- Fibroblasts/metabolism
- Fibroblasts/pathology
- Graves Ophthalmopathy/drug therapy
- Graves Ophthalmopathy/immunology
- Graves Ophthalmopathy/metabolism
- Graves Ophthalmopathy/pathology
- Humans
- Hyaluronic Acid/metabolism
- Immunoglobulins, Thyroid-Stimulating/metabolism
- Osmolar Concentration
- Phosphorylation/drug effects
- Protein Processing, Post-Translational/drug effects
- Proto-Oncogene Proteins c-akt/metabolism
- Pyridines/pharmacology
- Quinazolinones/pharmacology
- Receptors, Thyrotropin/agonists
- Receptors, Thyrotropin/antagonists & inhibitors
- Receptors, Thyrotropin/metabolism
- Signal Transduction/drug effects
- Thyrotropin/agonists
- Thyrotropin/antagonists & inhibitors
- Thyrotropin/pharmacology
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Affiliation(s)
- Adina F Turcu
- Division of Endocrinology, Diabetes, Metabolism and Nutrition, Mayo Clinic, 200 First Street Southwest, Rochester, Minnesota 55902, USA
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18
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Abstract
Graves' ophthalmopathy is an inflammatory autoimmune disorder of the orbit. The close clinical and temporal relationships between Graves' hyperthyroidism and ophthalmopathy have long suggested that both conditions derive from a single systemic process and share the thyrotropin receptor as a common autoantigen. This receptor is expressed not only in thyroid follicular cells, but also in orbital fibroblasts with higher levels measured in orbital cells from ophthalmopathy patients than in cells from normal individuals. Recent studies from several laboratories have shown that thyrotropin receptor activation in orbital fibroblasts enhances hyaluronic acid synthesis and adipogenesis, both cellular functions that appear to be upregulated in the diseased orbit. The phosphoinositide 3-kinase/Akt signaling cascade, along with other effector pathways including adenylyl cyclase/cAMP, appears to mediate these processes. Future therapies for this condition may involve inhibition of thyrotropin receptor signaling in orbital fibroblasts.
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Affiliation(s)
- Seethalakshmi Iyer
- Division of Endocrinology, Metabolism and Nutrition, Mayo Clinic, 200 First Street SW, Rochester, MN, USA 55905, , Phone 507 284-2462, Fax 507 266-2270
| | - Rebecca Bahn
- Corresponding author: , Mayo Clinic, 200 First Street SW, Rochester, MN, USA 55905, , Phone 507 284-9564, Fax 507 266-2270
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19
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Abstract
Smoking is the most important risk factor for the occurrence/progression of Graves' ophthalmopathy (GO), as well as for its lower/slower response to immunosuppression. Accordingly, refrain from smoking should be urged, both as primary prevention (removal of risk factors in Graves' patients without GO), secondary prevention (early detection and treatment of asymptomatic/very mild GO) and tertiary prevention (reduction of complications/disability of overt GO). A 6-month course of 200 μg/day sodium selenite can prevent progression of mild GO to more severe GO and is, therefore, a form of secondary prevention and, probably, primary prevention. Correction of thyroid dysfunction and stable maintenance of euthyroidism are important preventive measures. The optimal treatment for hyperthyroidism in patients with GO is uncertain, because evidence demonstrating the superiority of antithyroid drugs over thyroid ablation (radioiodine, thyroidectomy, or both) is lacking. If radioiodine is used, low-dose steroid prophylaxis is recommended, particularly in smokers, to prevent radioiodine-associated GO progression.
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Affiliation(s)
- Luigi Bartalena
- Department of Clinical and Experimental Medicine, University of Insubria, Endocrine Unit, Ospedale di Circolo, viale Borri, 57, 21100 Varese, Italy.
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20
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Smith TJ, Hegedüs L, Douglas RS. Role of insulin-like growth factor-1 (IGF-1) pathway in the pathogenesis of Graves' orbitopathy. Best Pract Res Clin Endocrinol Metab 2012; 26:291-302. [PMID: 22632366 PMCID: PMC3712747 DOI: 10.1016/j.beem.2011.10.002] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The etiology of Graves' orbitopathy (GO) remains enigmatic and thus controversy surrounds its pathogenesis. The role of the thyroid stimulating hormone receptor (TSHR) and activating antibodies directed against it in the hyperthyroidism of Graves' disease (GD) is firmly established. Less well elucidated is what part the TSHR pathway might play in the development of GO. Also uncertain is the participation of other cell surface receptors in the disease. Elevated levels of insulin-like growth factor-1 receptor (IGF-1R) have been found in orbital fibroblasts as well as B and T cells from patients with GD. These abnormal patterns of IGF-1R display are also found in rheumatoid arthritis and carry functional consequences. In addition, activating IgGs capable of displacing IGF-1 from IGF-1R have also been detected in patients with these diseases. IGF-1R forms a complex with TSHR which is necessary for at least some of the non-canonical signaling observed following TSHR activation. Functional TSHR and IGF-1R have also been found on fibrocytes, CD34⁺ bone marrow-derived cells from the monocyte lineage. Levels of TSHR on fibrocytes greatly exceed those found on orbital fibroblasts. When ligated by TSH or M22, a TSHR-activating monoclonal antibody, fibrocytes produce extremely high levels of several cytokines and chemokines. Moreover, fibrocytes infiltrate both the orbit and thyroid in GD. In sum, based on current evidence, IGF-1R and TSHR can be thought of as "partners in crime". Involvement of the former probably transcends disease boundaries, while TSHR may not.
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Affiliation(s)
- Terry J Smith
- University of Michigan Medical School, Ann Arbor, MI 48105, USA.
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van Steensel L, Hooijkaas H, Paridaens D, van den Bosch WA, Kuijpers RWAM, Drexhage HA, van Hagen PM, Dik WA. PDGF enhances orbital fibroblast responses to TSHR stimulating autoantibodies in Graves' ophthalmopathy patients. J Clin Endocrinol Metab 2012; 97:E944-53. [PMID: 22438231 DOI: 10.1210/jc.2012-1020] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
PURPOSE Thyroid-stimulating hormone receptor (TSHR) stimulating autoantibodies are associated with Graves' ophthalmopathy (GO), the orbital manifestation of Graves' disease (GD). TSHR autoantibody levels and orbital TSHR expression levels correlate positively with GO disease activity. Platelet-derived growth factors (PDGF) are increased in GO and potently activate orbital fibroblast effector functions. We investigated the possible relationship between PDGF and TSHR expression on orbital fibroblasts and how that influences the immunopathological effects of TSHR autoantibodies on orbital fibroblast activity. METHODS Orbital fibroblasts were stimulated with PDGF-AA, PDGF-AB, and PDGF-BB, and TSHR expression was determined by flow cytometry. Stimulatory effects of bovine TSH and GD immunoglobulins on orbital fibroblasts (with or without PDGF-BB preincubation) were determined by IL-6, IL-8, chemokine (C-C motif) ligand (CCL)-2, CCL5, CCL7, and hyaluronan ELISA. The TSHR blocking antibody K1-70 and the cAMP inhibitor H89 were used to determine involvement of TSHR signaling. RESULTS PDGF-AB and PDGF-BB stimulation increased TSHR expression on orbital fibroblasts, whereas PDGF-AA did not. Furthermore, stimulation with bovine TSH and immunoglobulins from GD patients induced IL-6, IL-8, CCL2, and hyaluronan production by orbital fibroblasts, and PDGF-BB preincubation enhanced this response of orbital fibroblasts. Blocking studies with a TSHR blocking antibody and a cAMP inhibitor inhibited these effects, indicating the involvement of TSHR signaling and thus of TSHR stimulating autoantibodies herein. CONCLUSIONS These findings indicate that PDGF-B containing PDGF isoforms amplify the immunopathological effects of TSHR-stimulating autoantibodies in GO patients by stimulating TSHR expression on orbital fibroblasts.
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Affiliation(s)
- L van Steensel
- Department of Immunology, Erasmus Medical Center, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands
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Kumar S, Iyer S, Bauer H, Coenen M, Bahn RS. A stimulatory thyrotropin receptor antibody enhances hyaluronic acid synthesis in graves' orbital fibroblasts: inhibition by an IGF-I receptor blocking antibody. J Clin Endocrinol Metab 2012; 97:1681-7. [PMID: 22399503 PMCID: PMC3339886 DOI: 10.1210/jc.2011-2890] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
CONTEXT Graves' ophthalmopathy (GO) is characterized by expanded volume of the orbital fat and extraocular muscle tissues and elevated levels of TSH receptor autoantibodies (TRAb). The expansion of orbital tissues involves accumulation of hyaluronic acid (HA) within the orbit. OBJECTIVE The objective of the study was to determine whether a monoclonal stimulatory TRAb (M22) impacts HA synthesis in GO orbital cells and, if so, whether this might be blocked by an IGF-I receptor (IGF-IR)-blocking antibody (1H7) or inhibitors of various downstream signaling cascades. DESIGN GO orbital fibroblast cultures (n = 6) were treated with M22, bovine TSH (bTSH), or IGF-I in serum-free medium. Some cultures also received 1H7, LY294002, rapamycin, or protein kinase A inhibitor. MAIN OUTCOME MEASURES HA production and phosphorylated Akt levels in media or immunoblotting for phosphorylated Akt were measured. RESULTS M22 or bTSH stimulated HA synthesis (2.1-fold with 100 ng/ml M22 and 1.9-fold with 10 U/liter bTSH; P < 0.05 each). M22-induced HA synthesis was inhibited by LY294002 or rapamycin but not by protein kinase inhibitor. HA synthesis stimulated by M22 or IGF-I was inhibited by 1H7 (mean 36.6 ± 5.6% and mean 45.8 ± 7.6%, respectively; P < 0.05 each). Similarly, M22- or IGF-I-stimulated Akt phosphorylation was inhibited by 1H7 (mean 54 ± 9.6 and 36.1 ± 8.8%, respectively; P = 0.01 each). CONCLUSIONS The stimulatory TRAb M22 increases HA production in undifferentiated GO orbital fibroblasts via phosphoinositide 3-kinase/phosphorylated AKT/mammalian target of rapamycin activation. Blockade of IGF-IR inhibits both HA synthesis and Akt phosphorylation induced by M22 or IGF-I in these cells, suggesting that TSH receptor and IGF-IR signaling may be closely linked in the GO orbit.
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Affiliation(s)
- Seema Kumar
- Division of Pediatric Endocrinology and Metabolism, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55902, USA
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23
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van Zeijl CJJ, Fliers E, van Koppen CJ, Surovtseva OV, de Gooyer ME, Mourits MP, Wiersinga WM, Miltenburg AMM, Boelen A. Thyrotropin receptor-stimulating Graves' disease immunoglobulins induce hyaluronan synthesis by differentiated orbital fibroblasts from patients with Graves' ophthalmopathy not only via cyclic adenosine monophosphate signaling pathways. Thyroid 2011; 21:169-76. [PMID: 20954819 DOI: 10.1089/thy.2010.0123] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Both expression of the thyrotropin receptor (TSHR) and the production of hyaluronan (HA) by orbital fibroblasts (OF) have been proposed to be implicated in the pathogenesis of Graves' ophthalmopathy (GO). HA is synthesized by three types of HA synthase. We hypothesized that TSHR activation by recombinant human TSH (rhTSH) and TSHR-stimulating Graves' disease immunoglobulins (GD-IgGs) via induced cyclic adenosine monophosphate (cAMP) signaling increases HA synthesis in differentiated OF from GO patients. METHODS Cultured human OF, obtained during decompression surgery from 17 patients with severe GO, were stimulated in vitro to differentiate into adipocytes. Differentiation was evaluated by phase-contrast microscopy. The differentiated OF were stimulated by rhTSH or by TSHR-stimulating GD-IgG. We measured cAMP using a biochemical assay, HA synthase mRNA expression by quantitative polymerase chain reaction, and HA in the supernatant by enzyme-linked immunosorbent assay. RESULTS All differentiated OF cultures expressed higher levels of TSHR mRNA than nondifferentiated OF cultures. Stimulation by rhTSH induced a marked cAMP response in 11 of 12 differentiated OF cultures, but no measurable HA response in all but one differentiated OF cultures. By contrast, stimulation by GD-IgG induced a moderate cAMP response in a number of differentiated OF cultures, but a marked HA response in the majority of differentiated OF cultures. CONCLUSION Stimulation of differentiated OF by GD-IgG, but not by rhTSH, induces HA synthesis in the majority of patients, suggesting that in most patients TSHR-mediated cAMP signaling does not play a pivotal role in GD-IgG-induced HA synthesis in differentiated OF cultures.
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Affiliation(s)
- Clementine J J van Zeijl
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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