Expression of Endogenous Putative TSH Binding Protein in Orbit
| Autor: | Samuel Lewin Evans, D. Aled Rees, Mohd Shazli Draman, Anjana S Haridas, Colin M. Dayan, Fiona Grennan-Jones, Carol M. Lane, Ilaria Muller, Daniel S Morris, Lei Zhang, Marian Ludgate, Peter N. Taylor |
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| Rok vydání: | 2021 |
| Předmět: |
Microbiology (medical)
endocrine system endocrine system diseases QH301-705.5 thyrostimulin Cellular differentiation Gene Expression Thyrotropin binding protein Microbiology Thyrotropin receptor Pathogenesis Western blot medicine Humans Biology (General) Molecular Biology Autoantibodies biology medicine.diagnostic_test Chemistry Binding protein Genetic Variation Receptors Thyrotropin General Medicine Molecular biology thyrotropin receptor eye diseases Graves’ Orbitopathy Graves Ophthalmopathy variant Adipogenesis biology.protein Disease Susceptibility Antibody Carrier Proteins Ex vivo Biomarkers |
| Zdroj: | Current Issues in Molecular Biology, Vol 43, Iss 126, Pp 1794-1804 (2021) Current Issues in Molecular Biology Volume 43 Issue 3 Pages 126-1804 |
| ISSN: | 1467-3045 1467-3037 |
| Popis: | Thyroid stimulating antibodies (TSAB) cause Graves’ disease and contribute to Graves’ Orbitopathy (GO) pathogenesis. We hypothesise that the presence of TSH binding proteins (truncated TSHR variants (TSHRv)) and/or nonclassical ligands such as thyrostimulin (α2β5) might provide a mechanism to protect against or exacerbate GO. We analysed primary human orbital preadipocyte-fibroblasts (OF) from GO patients and people free of GO (non-GO). Transcript (QPCR) and protein (western blot) expression levels of TSHRv were measured through an adipogenesis differentiation process. Cyclic-AMP production by TSHR activation was studied using luciferase-reporter and RIA assays. After differentiation, TSHRv levels in OF from GO were significantly higher than non-GO (p = 0.039), and confirmed in ex vivo analysis of orbital adipose samples. TSHRv western blot revealed a positive signal at 46 kDa in cell lysates and culture media (CM) from non-GO and GO-OF. Cyclic-AMP decreased from basal levels when OF were stimulated with TSH or Monoclonal TSAB (M22) before differentiation protocol, but increased in differentiated cells, and was inversely correlated with the TSHRv:TSHR ratio (Spearman correlation: TSH r = −0.55, p = 0.23, M22 r = 0.87, p = 0.03). In the bioassay, TSH/M22 induced luciferase-light was lower in CM from differentiated GO-OF than non-GO, suggesting that secreted TSHRv had neutralised their effects. α2 transcripts were present but reduced during adipogenesis (p < 0.005) with no difference observed between non-GO and GO. β5 transcripts were at the limit of detection. Our work demonstrated that TSHRv transcripts are expressed as protein, are more abundant in GO than non-GO OF and have the capacity to regulate signalling via the TSHR. |
| Databáze: | OpenAIRE |
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