Analysis of the roles of mutations in thyroid hormone receptor-β by a bacterial biosensor system

Area of Science:

• Endocrinology and Metabolism
• Molecular Biology
• Drug Discovery

Background:

• Thyroid hormone receptors (TRs) are crucial for metabolic and developmental processes.
• Mutations in TRs cause disorders, posing challenges for effective thyromimetic drug treatment.
• Understanding ligand-receptor interactions is key to developing targeted therapies.

Purpose of the Study:

• To analyze the binding characteristics of clinically relevant human TRβ mutants.
• To evaluate the efficacy of various agonist and antagonist compounds against TRβ mutants.
• To demonstrate the utility of an engineered bacterial hormone biosensor for TR research.

Main Methods:

• Utilized an engineered bacterial hormone biosensor to study six clinically observed TRβ mutations.
• Assessed the binding affinity of six agonist compounds (T3, T4, Triac, GC-1, KB-141, CO-23) and one antagonist (NH-3) to wild-type and mutant TRβ.
• Quantified the impact of mutations on ligand-binding capabilities.

Main Results:

• TRβ mutations significantly altered ligand-binding affinity, ranging from several-fold reduction to complete loss.
• Ligand-receptor interactions were highly dependent on both the specific mutation and the compound tested.
• The bacterial system successfully differentiated agonists from antagonists, identifying one mutation with increased antagonist activity.

Conclusions:

• The engineered bacterial biosensor is a rapid and effective tool for characterizing TRβ mutants.
• TRβ mutations exhibit diverse effects on ligand binding, necessitating personalized therapeutic approaches.
• Findings provide insights into TR-mediated disorders and guide the development of novel thyromimetic drugs.