Dataset Information

A drug-like antagonist inhibits thyrotropin receptor-mediated stimulation of cAMP production in Graves' orbital fibroblasts.

ABSTRACT:

Background

Fibroblasts (FIBs) within the retro-orbital space of patients with Graves' disease (GOFs) express thyrotropin receptors (TSHRs) and are thought to be an orbital target of TSHR-stimulating autoantibodies in Graves' ophthalmopathy (GO). Recently, we developed a low molecular weight, drug-like TSHR antagonist (NCGC00229600) that inhibited TSHR activation in a model cell system overexpressing TSHRs and in normal human thyrocytes expressing endogenous TSHRs. Herein, we test the hypothesis that NCGC00229600 will inhibit activation of TSHRs endogenously expressed in GOFs.

Methods

Three strains of GOFs, previously obtained from patients with GO, were studied as undifferentiated FIBs and after differentiation into adipocytes (ADIPs), and another seven strains were studied only as FIBs. ADIP differentiation was monitored by morphology and measurement of adiponectin mRNA. FIBs and ADIPs were treated with the TSH- or TSHR-stimulating antibody M22 in the absence or presence of NCGC00229600 and TSHR activation was monitored by cAMP production.

Results

FIBs contained few if any lipid vesicles and undetectable levels of adiponectin mRNA, whereas ADIPs exhibited abundant lipid vesicles and levels of adiponectin mRNA more than 250,000 times greater than FIBs; TSHR mRNA levels were 10-fold higher in ADIPs than FIBs. FIBs exhibited higher absolute levels of basal and forskolin-stimulated cAMP production than ADIPs. Consistent with previous findings, TSH stimulated cAMP production in the majority of ADIP strains and less consistently in FIBs. Most importantly, NCGC00229600 reduced both TSH- and M22-stimulated cAMP production in GOFs.

Conclusions

These data confirm previous findings that TSHR activation may cause increased cAMP production in GOFs and show that NCGC00229600 can inhibit TSHR activation in GOFs. These findings suggest that drug-like TSHR antagonists may have a role in treatment of GO.

SUBMITTER: Neumann S

PROVIDER: S-EPMC3407388 | biostudies-literature | 2012 Aug

REPOSITORIES: biostudies-literature

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Publications

A drug-like antagonist inhibits thyrotropin receptor-mediated stimulation of cAMP production in Graves' orbital fibroblasts.

Neumann Susanne S Pope Arthur A Geras-Raaka Elizabeth E Raaka Bruce M BM Bahn Rebecca S RS Gershengorn Marvin C MC

Thyroid : official journal of the American Thyroid Association 20120711 8

<h4>Background</h4>Fibroblasts (FIBs) within the retro-orbital space of patients with Graves' disease (GOFs) express thyrotropin receptors (TSHRs) and are thought to be an orbital target of TSHR-stimulating autoantibodies in Graves' ophthalmopathy (GO). Recently, we developed a low molecular weight, drug-like TSHR antagonist (NCGC00229600) that inhibited TSHR activation in a model cell system overexpressing TSHRs and in normal human thyrocytes expressing endogenous TSHRs. Herein, we test the hyp ...[more]

PMID: 22784331

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Project description:BackgroundGraves' ophthalmopathy (GO) is a frequent extrathyroidal complication of Graves' hyperthyroidism. Orbital fibroblasts contribute to both orbital tissue inflammation and remodeling in GO, and as such are crucial cellular elements in active GO and inactive GO. However, so far it is largely unknown whether GO disease progression is associated with functional reprogramming of the orbital fibroblast effector function. Therefore, the aim of this study was to compare both the proteome and global DNA methylation patterns between orbital fibroblasts isolated from active GO, inactive GO and healthy controls.MethodsOrbital fibroblasts from inactive GO (n=5), active GO (n=4) and controls (n=5) were cultured and total protein and DNA was isolated. Labelled and fractionated proteins were analyzed with a liquid chromatography tandem-mass spectrometer (LC-MS/MS). Data are available via ProteomeXchange with identifier PXD022257. Furthermore, bisulphite-treated DNA was analyzed for methylation pattern with the Illumina Infinium Human Methylation 450K beadchip. In addition, RNA was isolated from the orbital fibroblasts for real-time quantitative (RQ)-PCR. Network and pathway analyses were performed.ResultsOrbital fibroblasts from active GO displayed overexpression of proteins that are typically involved in inflammation, cellular proliferation, hyaluronan synthesis and adipogenesis, while various proteins associated with extracellular matrix (ECM) biology and fibrotic disease, were typically overexpressed in orbital fibroblasts from inactive GO. Moreover, orbital fibroblasts from active GO displayed hypermethylation of genes that linked to inflammation and hypomethylated genes that linked to adipogenesis and autoimmunity. Further analysis revealed networks that contained molecules to which both hypermethylated and hypomethylated genes were linked, including NF-?B, ERK1/2, Alp, RNA polymerase II, Akt and IFN?. In addition, NF-?B, Akt and IFN? were also identified in networks that were derived from the differentially expressed proteins. Generally, poor correlation between protein expression, DNA methylation and mRNA expression was observed.ConclusionsBoth the proteomics and DNA methylation data support that orbital fibroblasts from active GO are involved in inflammation, adipogenesis, and glycosaminoglycan production, while orbital fibroblasts from inactive disease are more skewed towards an active role in extracellular matrix remodeling. This switch in orbital fibroblast effector function may have therapeutic implications and further studies into the underlying mechanism are thus warranted.

Project description:Graves’ ophthalmopathy (GO) is an extrathyroidal complication of Graves’ hyperthyroidism. Orbital fibroblast, an important cell in the pathogenesis of GO, is responsible for GO characteristics during active and inactive stages; however, information on the extensive profiles and the mechanistic regulations behind orbital fibroblast phenotypes are currently limited. The aim of this study was to compare the proteome profile of orbital fibroblasts isolated from inactive GO, active GO and healthy control. The proteome profile was further integrated with global DNA methylation data to identify this epigenetics regulation involved in the pathogenesis of GO. Methods Orbital fibroblasts culture isolated from five inactive GO, four active GO and five controls were cultured for total protein and DNA extraction. The labelled and fractionated proteins were analyzed with a liquid chromatography tandem-mass spectrometer (LC-MS/MS). On the other hand, the bisulphite-treated DNA was measured with the Illumina Infinium Human Methylation 450K beadchip. Proteome and methylation data were validated by real-time quantitative (RQ)-PCR. Network, pathway and functional analysis were performed by Ingenuity (Qiagen). Results Orbital fibroblasts from active GO displayed overexpression of proteins typically involved with inflammation, cellular proliferation, hyaluronan synthesis and adipogenesis, while several proteins linked to extracellular matrix (ECM) biology and fibrotic disease were overexpressed in orbital fibroblasts from inactive GO. The DNA methylation patterns were similar in healthy control and inactive GO orbital fibroblasts which were distinct from active GO orbital fibroblasts. In orbital fibroblasts from active GO hypermethylated genes link to inflammation while those genes hypomethylated are involved in adipogenesis and autoimmune-related genes. For the network analysis, overlapped between hypermethylated and hypomethylated genes were observed including NF-B, ERK1/2, Alp, RNA polymerase II, Akt and IFNα. In addition, NF-κB, Akt and IFNα were also identified in networks from the differentially expressed proteins. In general, poor correlation between protein expression, DNA methylation and mRNA expression in our study was observed.

Project description:PURPOSE:Chemokines are involved in the pathogenesis of various autoimmune diseases, including Graves' orbitopathy (GO), but comprehensive analyses of the dynamics of these cytokines and their receptors in such diseases remain lacking. In this study, we investigated the expressions of chemokines and their receptors during adipogenesis and inflammation in primary cultured orbital fibroblasts from patients with GO. METHODS:The messenger RNA (mRNA) expression levels of chemokines were compared between GO (n = 6) and non-GO (n = 5) orbital tissues by real-time polymerase chain reaction. After adipogenesis was induced in primary cultured orbital fibroblasts from patients with GO (n =5) and following stimulation with interleukin (IL)-1? and tumor necrosis factor (TNF)-?, the mRNA expression levels of chemokines and their receptors were analyzed. RESULTS:Chemokines were significantly downregulated in GO orbital tissues compared to non-GO orbital tissues (p < 0.05). Adipogenesis resulted in a strong increase in mRNA expression levels of chemokines and their receptors at an early stage (day 1); however, expression levels started to decrease thereafter and, eventually, decreased to below basal levels at the end of adipogenesis (day 10). Following stimulation with IL-1? and TNF-?, the mRNA expression levels of chemokines and their receptors increased, showing different responses to various proinflammatory cytokines. CONCLUSIONS:Chemokines were strongly upregulated in the early phase of adipogenesis before decreasing continuously until the end of adipogenesis. Also, overt mature GO tissues showed reduced mRNA expression of chemokines compared to controls, which might indicate the existence of a shorter window for effective medical inflammatory treatment. The heightened levels of chemokines and their receptors observed after stimulation with IL-1? and TNF-? suggest a crucial role of proinflammatory cytokines in the pathogenesis of GO and, further, support the idea that chemokines could be used as biomarkers of GO activity.

Dataset Information

A drug-like antagonist inhibits thyrotropin receptor-mediated stimulation of cAMP production in Graves' orbital fibroblasts.

Background

Methods

Results

Conclusions

Publications

A drug-like antagonist inhibits thyrotropin receptor-mediated stimulation of cAMP production in Graves' orbital fibroblasts.

Similar Datasets

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