Dataset Information

TSH-Mediated TNF? Production in Human Fibrocytes Is Inhibited by Teprotumumab, an IGF-1R Antagonist.

ABSTRACT:

Purpose

Fibrocytes (FC) are bone marrow-derived progenitor cells that are more abundant and infiltrate the thyroid and orbit in Graves orbitopathy (GO). FCs express high levels of thyrotropin receptor (TSHR) and insulin-like growth factor-1 receptor (IGF-1R). These receptors are physically and functionally associated, but their role in GO pathogenesis is not fully delineated. Treatment of FCs with thyroid stimulating hormone (TSH) or M22 (activating antibody to TSHR) induces the production of numerous cytokines, including tumor necrosis factor ? (TNF?). Teprotumumab (TMB) is a human monoclonal IGF-1R blocking antibody currently in clinical trial for GO and inhibits TSHR-mediated actions in FCs.

Aim

To characterize the molecular mechanisms underlying TSH-induced TNF? production by FCs, and the role of IGF-1R blockade by TMB.

Design

FCs from healthy and GD patients were treated with combinations of TSH, M22, MG132 and AKTi (inhibitors of NF-?B and Akt, respectively), and TMB. TNF? protein production was measured by Luminex and flow cytometry. Messenger RNA expression was quantified by real time PCR.

Results

Treatment with TSH/M22 induced TNF? protein and mRNA production by FCs, both of which were reduced when FCs were pretreated with MG132 and AKTi (p<0.0001). TMB decreased TSH-induced TNF? protein production in circulating FCs from mean fluorescent index (MFI) value of 2.92 to 1.91, and mRNA expression in cultured FCs from 141- to 52-fold expression (p<0.0001). TMB also decreased M22-induced TNF? protein production from MFI of 1.67 to 1.12, and mRNA expression from 6- to 3-fold expression (p<0.0001).

Conclusion

TSH/M22 stimulates FC production of TNF? mRNA and protein. This process involves the transcription factor NF-?B and its regulator Akt. Blocking IGF-1R attenuates TSH/M22-induced TNF? production. This further delineates the interaction of TSHR and IGF1-R signaling pathways. By modulating the proinflammatory properties of FCs such as TNF? production, TMB may be a promising therapeutic agent for GO.

SUBMITTER: Chen H

PROVIDER: S-EPMC4472723 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

TSH-Mediated TNFα Production in Human Fibrocytes Is Inhibited by Teprotumumab, an IGF-1R Antagonist.

Chen Hong H Shan Shannon J C SJ Mester Tünde T Wei Yi-Hsuan YH Douglas Raymond S RS

PloS one 20150618 6

<h4>Purpose</h4>Fibrocytes (FC) are bone marrow-derived progenitor cells that are more abundant and infiltrate the thyroid and orbit in Graves orbitopathy (GO). FCs express high levels of thyrotropin receptor (TSHR) and insulin-like growth factor-1 receptor (IGF-1R). These receptors are physically and functionally associated, but their role in GO pathogenesis is not fully delineated. Treatment of FCs with thyroid stimulating hormone (TSH) or M22 (activating antibody to TSHR) induces the producti ...[more]

PMID: 26087256

Similar Datasets

Project description:ContextThe molecular basis for anatomically dispersed clinical manifestations in Graves' disease (GD) eludes our understanding. Bone marrow-derived, pluripotent fibrocytes represent a subset of peripheral blood mononuclear cells and infiltrate the orbital and thyroid tissues in GD. These cells may be involved in the pathogenesis of thyroid-associated ophthalmopathy (TAO).ObjectiveThe objective of the study was to quantify fibrocyte display of functional cell surface TSH receptor (TSHR), identify the profile of chemokines they express after TSHR activation, and determine whether circulating TSHR(+) peripheral blood fibrocytes are more frequent in situ in patients with TAO.Design/setting/participantsUsing a newly developed technique, fibrocytes were directly identified in peripheral blood from 31 patients with TAO and 19 healthy subjects receiving care at a multidisciplinary academic center.Main outcome measuresThe frequency in situ of fibrocytes (collagen 1(+), CD45(+), CD34(+), CD14(+), CD86(+) peripheral blood mononuclear cells) was assessed by multiparameter flow cytometry and correlated to clinical disease activity and smoking status. Levels of TSHR-displaying fibrocytes and their response to TSH and TSHR-activating antibody, M22, were measured by flow cytometry, Luminex, and real-time PCR.ResultsThe levels of TSHR expression by fibrocytes are substantially higher than those found in orbital fibroblasts. Moreover, the frequency of TSHR(+) fibrocytes in patients with TAO was greater than that in healthy subjects in situ. Their abundance is not influenced by disease activity or smoking history. These cells produce high levels of several cytokines and chemokines including IL-8, regulated upon activation, normal T cell expressed and secreted, and monocyte chemoattractant protein-1 when treated with TSH or M22. TSH induces IL-8 production at the pretranslational level. This induced cytokine can be detected in intact fibrocytes ex vivo.ConclusionsFrequency of circulating TSHR(+) fibrocytes is markedly increased in patients with TAO, and they express proinflammatory chemokines in response to TSH. Because they infiltrate both orbit and thyroid in GD, they may represent the link between systemic immunoreactivity and organ-specific autoimmunity.

Project description:BackgroundExosomes may contain excess cellular components released by cells in response to harmful external stimuli to maintain cellular homeostasis. Inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), can induce cell apoptosis, alter cellular component expression levels, and stimulate exosome release. In this study, we examined whether exosomes released from nucleus pulposus cells (NPCs) under inflammatory conditions could induce normal NP cell apoptosis in rats and its underlining mechanism.MethodsExosomes were isolated from TNF-α-treated NPCs and used to treat normal NPCs. The effects were assessed by flow cytometry and western blot analysis. Anti-apoptotic insulin-like growth factor-1 (IGF-1) expression in NPCs was assessed by western blot analysis. Given the exosomal miRNAs might be the key factors of exosomes, bioinformatics approaches and quantitative real-time polymerase chain reaction (qRT-PCR) were used to identify IGF-1-regulating micro RNAs (miRNAs), including miR-16. Luciferase reporter assay assessed miR-16 regulation of IGF-1 and IGF-1 receptor (IGF-1R). NPCs were transfected with miR-16 mimic, and exosomes were applied to normal NPCs. NPCs were pretreated with 10 ng/mL TNF-α, transfected with miR-16 inhibitors, and the exosomes were isolated. Cell and exosome miR-16 levels were detected by qRT-PCR. Western blot analysis determined IGF-1, IGF-1R, and apoptotic marker levels in exosome-treated NPCs.ResultsExosomes from TNF-α-treated NPCs induced apoptosis in normal NPCs and repressed IGF-1 expression. Exosomal miR-16 regulated IGF-1 and induced NPC apoptosis. The dual-luciferase reporter assay revealed that miR-16 binds the 3' untranslated regions (3'-UTRs) of IGF-1 and IGF-1R. Exosomal miR-16 repressed IGF-1 and the IGF-1R/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway which therefore induced NPC apoptosis. Rescue experiments using miR-16 inhibitors further validated these findings.ConclusionsThe inflammatory factor TNF-α stimulated exosome release from NPCs, which induced the apoptosis of normal NPCs through the actions of exosomal miR-16. Exosomal miR-16 directly repressed the anti-apoptotic IGF-1/IGF-1R pathway, increasing the apoptosis of NPCs.

Project description:Primary bone tumor, also known as osteosarcoma (OS), is the most common primary malignancy of bone in children and young adults. Current treatment protocols yield a 5-year survival rate of near 70% although approximately 80% of patients have metastatic disease at the time of diagnosis. However, long-term survival rates have remained virtually unchanged for nearly four decades, largely due to our limited understanding of the disease process. One major signaling pathway that has been implicated in human OS tumorigenesis is the insulin-like growth factor (IGF)/insulin-like growth factor-1 receptor (IGF1R) signaling axis. IGF1R is a heterotetrameric α2β2 receptor, in which the α subunits comprise the ligand binding site, whereas the β subunits are transmembrane proteins containing intracellular tyrosine kinase domains. Although numerous strategies have been devised to target IGF/IGF1R axis, most of them have failed in clinical trials due to the lack of specificity and/or limited efficacy. Here, we investigated whether a more effective and specific blockade of IGF1R activity in human OS cells can be accomplished by employing dominant-negative IGF1R (dnIGF1R) mutants. We engineered the recombinant adenoviruses expressing two IGF1R mutants derived from the α (aa 1-524) and β (aa 741-936) subunits, and found that either dnIGF1Rα and/or dnIGF1Rβ effectively inhibited cell migration, colony formation, and cell cycle progression of human OS cells, which could be reversed by exogenous IGF1. Furthermore, dnIGF1Rα and/or dnIGF1Rβ inhibited OS xenograft tumor growth in vivo, with the greatest inhibition of tumor growth shown by dnIGF1Rα. Mechanistically, the dnIGF1R mutants down-regulated the expression of PI3K/AKT and RAS/RAF/MAPK, BCL2, Cyclin D1 and most EMT regulators, while up-regulating pro-apoptotic genes in human OS cells. Collectively, these findings strongly suggest that the dnIGF1R mutants, especially dnIGF1Rα, may be further developed as novel anticancer agents that target IGF signaling axis with high specificity and efficacy.

Project description:Abstract Introduction: Teprotumumab treatment resulted in statistically and clinically meaningful improvements across multiple facets of active TED and was generally well-tolerated in Phase 2 and 3 trials.1,2 An initial intravenous infusion of 10 mg/kg followed by 20 mg/kg every 3 weeks was selected based on in vitro activity and clinical PK profile, to maintain pharmacologically active exposures and >90% saturation of IGF-1R over dosing intervals and to achieve efficacy at a well-tolerated dose for this vision-threatening disease. Methods: Population PK analysis were performed on data from a Phase 1 oncology study (n=60)3 and Phase 2 and 3 trials in active TED (N=83)2,3 and covariate effect on PK was assessed. Exposure-response relationship was evaluated in TED studies for key efficacy endpoints (proptosis response rate, % patients with a clinical activity score value of 0 or 1, and diplopia responder rate) and selected safety variables (hyperglycemia and muscle spasms). Results: Teprotumumab PK was linear in TED patients and consistent with other immunoglobulin G1 monoclonal antibodies (IgG1 mAbs), with low systemic clearance (0.334 L/day), low volume of distribution (3.9 L for central compartment and 4.2 L for peripheral compartment), and long elimination half-life (19.9 days). 4,5 Model-predicted mean (± standard deviation) steady-state area under the concentration curve (AUCss), peak (Cmax,ss), and trough (Cmin,ss) concentrations in TED patients were 131 (± 30.9) mg∙hr/mL, 643 (± 130) µg/mL and 157 (± 50.6) µg/mL, respectively, suggesting low inter-subject variability. Population PK analysis indicated no significant impact of baseline age, gender, race, weight, smoking status, renal impairment (mild/moderate), and hepatic function (total bilirubin, aspartate and alanine aminotransferases) on teprotumumab PK. Female patients had 15% higher Cmax,ss but similar AUC compared to male patients, which is not considered clinically relevant. Exposure-response analysis from the TED dose regimen indicated no meaningful correlations between exposures (AUCss, Cmax,ss and Cmin,ss) and key efficacy endpoints or selected safety variables, supporting the demonstrated, favorable benefit-risk profile of the TED dose regimen.2 Conclusion: Teprotumumab PK was characterized in TED patients by long elimination half-life, low systemic clearance and low volume of distribution, consistent with other IgG1 mAbs. There was no meaningful exposure-response relationship at the selected TED dose regimen for both efficacy and safety endpoints, supporting the teprotumumab dose regimen used in TED patients. Reference: (1) Smith TJ, et al. N Engl J Med 2017;376:1748-1761. (2) Douglas RS, et al. AACE 2019 late-breaking abstract. (3) ClinicalTrials.gov: NCT00400361. (4) Dirks NL et al. Clin Pharmacokinet. 2010;49(10):633-59. (5) Ryman JT et al. CPT Pharmacometrics Syst Pharmacol. 2017;6(9):576-88.