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Evidence That Graves' Ophthalmopathy Immunoglobulins Do Not Directly Activate IGF-1 Receptors.

ABSTRACT: BACKGROUND:Graves' ophthalmopathy (GO) pathogenesis involves thyrotropin (TSH) receptor (TSHR)-stimulating autoantibodies. Whether there are autoantibodies that directly stimulate insulin-like growth factor 1 receptors (IGF-1Rs), stimulating insulin-like growth factor receptor antibodies (IGFRAbs), remains controversial. This study attempted to determine whether there are stimulating IGFRAbs in patients with GO. METHODS:Immunoglobulins (Igs) were purified from normal volunteers (NV-Igs) and patients with GO (GO-Igs). The effects of TSH, IGF-1, NV-Igs, and GO-Igs on pAKT and pERK1/2, members of pathways used by IGF-1R and TSHR, were compared in orbital fibroblasts from GO patients (GOFs) and U2OS-TSHR cells overexpressing TSHRs, and U2OS cells that express TSHRs at very low endogenous levels. U2OS-TSHR and U2OS cells were used because GOFs are not easily manipulated using molecular techniques such as transfection, and U2OS cells because they express TSHRs at levels that do not measurably stimulate signaling. Thus, comparing U2OS-TSHR and U2OS cells permits specifically distinguishing signaling mediated by the TSHR and IGF-1R. RESULTS:In GOFs, all GO-Igs stimulated pERK1/2 formation and 69% stimulated pAKT. In U2OS-TSHR cells, 15% of NV-IGs and 83% of GO-Igs stimulated increases in pERK1/2, whereas all NV-Igs and GO-Igs stimulated increases in pAKT. In U2OS cells, 70% of GO-Igs stimulated small increases in pAKT. Knockdown of IGF-1R caused a 65?±?6.3% decrease in IGF-1-stimulated pAKT but had no effect on GO-Igs stimulation of pAKT. Thus, GO-Igs contain factor(s) that stimulate pAKT formation. However, this factor(s) does not directly activate IGF-1R. CONCLUSIONS:Based on the findings analyzing these two signaling pathways, it is concluded there is no evidence of stimulating IGFRAbs in GO patients.

SUBMITTER: Marcus-Samuels B

PROVIDER: S-EPMC5952334 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

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Evidence That Graves' Ophthalmopathy Immunoglobulins Do Not Directly Activate IGF-1 Receptors.

Marcus-Samuels Bernice B Krieger Christine C CC Boutin Alisa A Kahaly George J GJ Neumann Susanne S Gershengorn Marvin C MC

Thyroid : official journal of the American Thyroid Association 20180430 5

<h4>Background</h4>Graves' ophthalmopathy (GO) pathogenesis involves thyrotropin (TSH) receptor (TSHR)-stimulating autoantibodies. Whether there are autoantibodies that directly stimulate insulin-like growth factor 1 receptors (IGF-1Rs), stimulating insulin-like growth factor receptor antibodies (IGFRAbs), remains controversial. This study attempted to determine whether there are stimulating IGFRAbs in patients with GO.<h4>Methods</h4>Immunoglobulins (Igs) were purified from normal volunteers (N ...[more]

PMID: 29631510

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Project description:BackgroundA large gene region, called GD-1, was first described by this laboratory as linked to Graves' disease (GD) and included the gene for the thyroid-stimulating hormone receptor (TSHR). Recent studies have now suggested an association of TSHR intronic polymorphisms with GD. We have taken the opportunity to examine a population of well-characterized patients with autoimmune thyroid disease (AITD) typed for an additional thyroid susceptibility gene, the immunoregulatory gene for cytotoxic T-lymphocyte antigen 4 (CTLA-4), to examine its relationship with the susceptibility to GD endowed by TSHR gene polymorphisms.MethodsWe used TSHR-SNP-rs2268458, located in intron 1 of the TSHR gene, measured using standard PCR-RFLP procedures, as our marker for the TSHR gene association. We genotyped 200 patients with GD, 83 patients with Hashimoto's thyroiditis (HT), and 118 healthy controls (all female Caucasians).ResultsThe allele and genotype frequencies from GD patients, but not HT patients, were significantly different from controls. The frequency of the combined genotype (allele) CC + TC was significantly higher in GD patients versus controls, suggesting that the C-containing genotype increased the risk for GD in a dominant manner (p = 0.018, odds ratio [OR] = 1.8). When compared with CTLA-4 (A/G)(49) single-nucleotide polymorphism (SNP), we were unable to demonstrate additive risk in patients with established AITD. Further, subsetting the patients (n = 120) into those with clinically significant Graves' ophthalmopathy (GO) showed no association with the TSHR SNP.ConclusionsThese results demonstrated that the intronic TSHR-SNP-rs2268458 was associated with GD, but not with HT, thus indicating that the TSHR gene has the potential to increase susceptibility to GD. However, we were not able to demonstrate any additive risk with the CTLA-4 (A/G)(49) SNP, which is, therefore, an independent risk factor for AITD. This suggested that, within the limits of the study population, each of these two genes provided a small contribution to GD susceptibility and that neither was essential. In addition, there was no evidence for the TSHR gene association adding to the risk of developing GO. Direct functional analyses are now needed to help explain the mechanisms of this TSHR gene susceptibility to GD.

Project description:BackgroundSeveral immunosuppressive therapeutic regimens are widely used to treat Graves' ophthalmopathy (GO), including oral glucocorticoids (OGC), intravenous glucocorticoids (IVGC), retrobulbar injections of glucocorticoids (ROGC) and orbital radiotherapy (OR). The priority among these is unknown. This meta-analysis investigated the efficacy and tolerability of the above regimens.MethodsThe PubMed, EMBASE, and Cochrane Library databases and the Chinese Biomedicine Database were searched up to November 18, 2014. Randomized controlled trials (RCTs) comparing monotherapies (OGC, IVGC, ROGC and OR) in patients with moderate-to-severe active GO were selected. The main efficacy measures were the response rate, the standard mean difference (SMD) in the reduction in the clinical activity score (CAS) and the mean difference (MD) in proptosis from baseline to the end of treatment. The main tolerability measure was the risk ratio (RR) for adverse events. The pooled estimates and 95% confidence intervals (95% CIs) were calculated using the RevMan software, version 5.1.ResultsSeven published RCTs involving 328 participants were included in the present meta-analysis, including IVGC versus OGC (3 trials), ROGC versus OGC (3 trials) and OR versus OGC (1 trial). IVGC was more effective than OGC in response rate (RR = 1.48, 95% CI = 1.18-1.87) and had an obvious CAS reduction (SMD = 0.69, 95% CI = 0.13-1.25). IVGC caused fewer adverse events than OGC. ROGC and OGC had no statistically significant difference in response rate (RR = 1.16, 95% CI = 0.94-1.42). OR also did not differ significantly compared with OGC (RR = 0.93, 95% CI = 0.54-1.60). ROGC and OR had fewer adverse events, such as weight gain, compared with OGC.ConclusionsFor patients with GO in the moderate-to-severe active phase, current evidence gave priority to IVGC, which had a statistically significant advantage over OGC and caused fewer adverse events. ROGC and OR did not provide greater efficacy than OGC, although better tolerability and fewer adverse events were shown.

Project description:BackgroundGraves' ophthalmopathy (GO) significantly impairs the quality of life of affected individuals and the most severe cases can be sight threatening. Given the limited therapeutic options, a strong emphasis should be placed on disease prevention to diminish the significant morbidity associated with this disease.SummaryGO is most prevalent in women and most severe in men. Although some genetic differences between GO patients and Graves' disease patients without ophthalmopathy have been identified, none of the polymorphisms identified to date impart a high enough risk of GO to justify genetic testing to guide therapy or preventive strategies. Poorly defined mechanical factors that appear also to play a role in GO susceptibility will likely be better elucidated with advances in imaging techniques. Tobacco smoking has been consistently linked to development or deterioration of GO. Smokers who receive radioactive iodine have the highest incidence of unfavorable GO outcome, which is proportional to the number of cigarettes smoked per day. Several studies have reported an association between radioactive iodine treatment for Graves' disease and worsening or development of GO. Observational studies suggest that the same appears to be true for thyroid dysfunction, including both hyper- and hypothyroidism. While thyrotropin receptor antibody levels appear to be useful in predicting the course of disease and response to therapy, it is not known whether they are predictive of GO development. The puzzling scenarios of euthyroid or clinically unilateral GO, the large number of nonsmoking GO patients, and the occasional development of GO years after thyroid dysfunction has been treated all underline the multifactorial etiology of this disorder in which no single factor determines the clinical outcome.ConclusionsGO appears to have a complex genetic basis with multiple susceptibility alleles that act in combination with nongenetic factors to contribute to disease expression.

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Evidence That Graves' Ophthalmopathy Immunoglobulins Do Not Directly Activate IGF-1 Receptors.

Publications

Evidence That Graves' Ophthalmopathy Immunoglobulins Do Not Directly Activate IGF-1 Receptors.

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