title: A small molecule antagonist inhibits thyrotropin receptor antibody-induced orbital fibroblast functions involved in the pathogenesis of Graves ophthalmopathy.
abstract: BACKGROUND
  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).
  
  
  METHODS
  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.
  
  
  METHODS
  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.
authors.affiliation: Division of Endocrinology, Diabetes, Metabolism and Nutrition, Mayo Clinic, 200 First Street Southwest, Rochester, Minnesota 55902, USA.
authors.forename: Adina F
authors.initials: AF
authors.lastname: Turcu
authors.forename: Seema
authors.initials: S
authors.lastname: Kumar
authors.forename: Susanne
authors.initials: S
authors.lastname: Neumann
authors.forename: Michael
authors.initials: M
authors.lastname: Coenen
authors.forename: Seethalakshmi
authors.initials: S
authors.lastname: Iyer
authors.forename: Pamela
authors.initials: P
authors.lastname: Chiriboga
authors.forename: Marvin C
authors.initials: MC
authors.lastname: Gershengorn
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Bahn
mesh_terms: D052436:Adipose Tissue, White / Q000187:drug effects / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D000911:Antibodies, Monoclonal / Q000378:metabolism; D054337:Cell Dedifferentiation; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D054314:Drug Inverse Agonism; D005123:Eye / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D005347:Fibroblasts / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D049970:Graves Ophthalmopathy / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D006801:Humans; D006820:Hyaluronic Acid / Q000378:metabolism; D018828:Immunoglobulins, Thyroid-Stimulating / Q000378:metabolism*; D009994:Osmolar Concentration; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology*; D052999:Quinazolinones / Q000494:pharmacology*; D011989:Receptors, Thyrotropin / Q000819:agonists / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013972:Thyrotropin / Q000819:agonists / Q000037:antagonists & inhibitors / Q000494:pharmacology
chemical_list: C582068:2-(3-((2,6-dimethylphenylthio)methyl)-4-methoxyphenyl)-3-(furan-2-ylmethyl)-2,3-dihydroquinazolin-4(1H)-one; D000911:Antibodies, Monoclonal; D018828:Immunoglobulins, Thyroid-Stimulating; C556685:NCGC 00229600; D011725:Pyridines; D052999:Quinazolinones; D011989:Receptors, Thyrotropin; D013972:Thyrotropin; D006820:Hyaluronic Acid; D000242:Cyclic AMP; D051057:Proto-Oncogene Proteins c-akt