ML224 : TSHR (Thyroid Stimulating Hormone Receptor) Inverse agonist

ML224
Target Name
Thyroid Stimulating Hormone Receptor
Target Alias
TSHR
Target Class
G-protein Coupled Receptor
Mechanism of Action
Inverse agonist of TSHR
Biology / Disease Relevance
Thyroid homeostasis, TSHR biology
In vitro activity
TSHR bioassay (IC50)Cellular activity
TSHR ELISA assay (IC50)Target Information
Thyroid Stimulating Hormone (TSH) is a heterodimeric glycoprotein hormone that regulates thyroid homeostasis upon interaction with the TSH receptor (TSHR). TSH binds to the TSH receptor, which couples preferentially to the G-alpha (s) (Gs) protein, resulting in activation of adenylate cyclase and an increase in cyclic adenosine 3’, 5’ monophosphate (cAMP). Preliminary structure activity relationship studies led to the discovery of a selective TSHR inverse agonist, ML224, which could be a useful tool for studying TSHR functions; it could also be a potential lead for development of drugs to treat TSHR-mediated hyperthyroidism caused by constitutively activating mutations or stimulating auto-antibodies associated with Graves’ disease.
Properties

ML224
NCGC00242364
Physical & chemical properties | ||||
---|---|---|---|---|
Molecular Weight | 525.6 g/mol | |||
Molecular Formula | C31H31N3O5 | |||
cLogP | 4.7 | |||
PSA | 93 Ų | |||
Storage | ||||
Solubility | ||||
CAS Number | 1338824-21-7 |
SMILES:
COC1=C(COC2=C(C)C=C(NC(C)=O)C=C2C)C=C(C3NC4=C(C(N3CC5=CC=CO5)=O)C=CC=C4)C=C1
InChI:
1S/C31H31N3O5/c1-19-14-24(32-21(3)35)15-20(2)29(19)39-18-23-16-22(11-12-28(23)37-4)30-33-27-10-6-5-9-26(27)31(36)34(30)17-25-8-7-13-38-25/h5-16,30,33H,17-18H2,1-4H3,(H,32,35)
InChIKey:
BFTSWGYWHRJVNI-UHFFFAOYSA-N
Activity
Summary activity statement /
Thyroid Stimulating Hormone (TSH) is a heterodimeric glycoprotein hormone that regulates thyroid homeostasis upon interaction with the TSH receptor (TSHR). TSH binds to the TSH receptor, which couples preferentially to the G-alpha (s) (Gs) protein, resulting in activation of adenylate cyclase and an increase in cyclic adenosine 3’, 5’ monophosphate (cAMP)1. TSHR exhibits basal (agonist-independent or constitutive) signaling, and the current state of the art is lacking any small-molecule TSHR inverse agonists. ML224 (SID 109967290; CID 50897809) is a member of a series of TSHR modulators and selectively inhibits TSH-stimulated cAMP production with an IC50 = 2.3 μM, and TSHR basal activity with an IC50 = 6 μM. This probe can be used to study TSHR functions in vitro; it could also be used as a lead for development of drugs to treat hyperthyroidism caused by TSHR constitutively activating mutations or stimulating auto-antibodies associated with Graves’ disease.
In vitro activity - Selectivity Assay
Bioassay | ML224 (IC50) |
---|---|
TSHR |
2300 nM |
LHR (Anti-Target) |
Inactive |
FSHR (Anti-Target) |
Inactive |
Summary /
ML209 is found to have > 20 fold selective against the TSHR vs. other hormone receptor.

Figure 1. Activity of ML224 at the three glycoprotein hormone receptors in the ELISA cAMP assays. The compound is selective towards the TSHR.
Cellular activity - Human Thyrocytes and HEK-EM 293 cell
Summary /
TSHR antagonists from this series were found to be active against the THSH expressed stably in HEK-EM 293 cells and primary cultures of human thyrocytes (AID 504380) . No toxicity has been seen in in vitro studies in HEK cells stably expressing the TSHR and in primary cultures of human thyrocytes.
In vitro activity - Mechanism of Action Study
Summary /
A Schild analysis of TSH-stimulated cAMP production shows that CID 2887926 acts as a competitive antagonist of TSH signaling. The Schild plot of these data was linear with a slope of 1.0, which is typical for a competitive ligand. CID 2887926 had no effect on [125I] TSH binding to TSHRs on the surface of HEK-EM 293 cells. A lack of effect of CID 2887926 on TSH binding was expected because we have previously shown that CID 25246343, a TSHR agonist that contains the same scaffold as CID 2887926, does not affect TSH binding and provided evidence that it binds in the transmembrane domain of TSHR24. We assume that CID 2887926 and other TSHR antagonists from these series bind in the serpentine region of TSHR.
References
- PubChem link: qHTS Assay for Inverse Agonists of the Thyroid Stimulating Hormone Receptor: Summary
- Huang W, Englund E, Titus S, et al. Identification of Thyroid Stimulating Hormone Receptor Inverse Agonists. 2011 Mar 31 [Updated 2013 Feb 28]. In: Probe Reports from the NIH Molecular Libraries Program [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2010-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK133424/
- RT-PCR Analysis of TSH-dependent transcripts in primary cultures of human thyrocytes