qHTS Assay for Inverse Agonists of the Thyroid Stimulating Hormone Receptor: Summary
TSH is an alpha/beta heterodimeric glycoprotein hormone secreted from the anterior pituitary gland which belongs to the glycoprotein hormone family. The actions of TSH are mediated by a seven-transmembrane receptor, which upon TSH binding couples preferentially to the G-alpha (s) protein (Gs), resulting in activation of adenylate cyclase and increase in cyclic adenosine 3', 5' monophosphate more ..
TSH is an alpha/beta heterodimeric glycoprotein hormone secreted from the anterior pituitary gland which belongs to the glycoprotein hormone family. The actions of TSH are mediated by a seven-transmembrane receptor, which upon TSH binding couples preferentially to the G-alpha (s) protein (Gs), resulting in activation of adenylate cyclase and increase in cyclic adenosine 3', 5' monophosphate (cAMP). The TSH receptor (THSR) is mainly expressed in thyroid follicular cells and regulates their growth and function. This cell based assay was conducted on a TSHR transfected HEK 293 cell line, measuring cAMP stimulation using antibody-based Homogeneous Time Resolved Fluorescence (HTRF).
Our goal is to identify small molecules that will inhibit (antagonize) the thyroid-stimulating hormone receptor (TSHR), a member of the 7 transmembrane-spanning receptor (7TMR) family of cell surface receptors. TSHR-mediated hyperthyroidism is important in thyroid pathology. The development of small molecule antagonists of TSHR may lead to therapeutic approaches for TSHR-mediated hyperthyroidism caused by constitutively activating mutations or stimulating auto-antibodies associated with Graves' disease. Graves' disease is the leading cause of hyperthyroidism and is caused by autoantibodies that stimulate TSHR (TsAbs) causing thyroid growth and unregulated overproduction of thyroid hormones and existing treatments have liabilities (agranulocytosis). In addition, TSHRs are known to be expressed in multiple extrathyroidal tissues including bone, brain, kidney, testis, fat and cells of the immune system but the role of the TSHR in these tissues is not clear. Therefore, TSHR antagonists/inverse agonists could be used as probes of extrathyroidal TSHR function. Finally, TSHR inverse agonists, which are a subclass of antagonists that inhibit agonist-independent (or basal or constitutive) TSHR signaling, could be used to inhibit TSH-independent signaling in patients with recurrent or metastatic thyroid cancer who are receiving thyroid hormone to suppress TSH.
This summary is written for the purposes of summarizing the probe activities from the project. MLSCN probes are given a score of 100. Molecules in the prior art are given a score of 80. Other, less active molecules in the same chemical series as the probe molecules are given a score of 50. Inactive analogues from these series are given a score of 0. The primary screen for this project is still being completed.
Categorized Comment - additional comments and annotations
Assay Cell Type: HEK293
From MLP Probe Report:
Probe count: 1
MLP Probe ML# for probe 1: ML224
PubChem Substance ID (SID) for probe 1: 109967290
PubChem Compound ID (CID) for probe 1: 50897809
Probe type for probe 1: Inhibitor
IC50/EC50 (nM) for probe 1: 2300
Target for probe 1: TSHR (gi: 38016895)
Disease relevance for probe 1: Hyperthyroidism
Anti-target for probe 1: LHR, FSHR
Fold selectivity for probe 1: >20
NCBI Book chapter link for probe 1: http://www.ncbi.nlm.nih.gov/books/NBK133424/ (ID: 3025830)
Grant number for probe 1: MH090855-01
NCBI Book chapter title for probe 1: Identification of Thyroid Stimulating Hormone Receptor Inverse Agonists