Structural determinants of non-covalent PPARγ inverse agonism and their therapeutic implications

Abstract

Peroxisome proliferator-activated receptor gamma (PPARγ) is a validated therapeutic target for type 2 diabetes (T2D), but current FDA-approved agonists are limited by adverse effects. SR10171, a non-covalent partial inverse agonist with modest binding potency, improves insulin sensitivity in mice without bone loss or marrow adiposity. Here, we characterize a series of SR10171 analogs to define structure-function relationships using biochemical assays, hydrogen-deuterium exchange (HDX), and computational modeling. Analogs featuring flipped indole scaffolds with N-alkyl substitutions exhibited 10- to 100-fold enhanced binding to PPARγ while retaining inverse agonist activity. HDX and molecular dynamic simulations revealed that ligand-induced dynamics within ligand-binding pocket and AF2 domain correlate with enhanced receptor binding and differential repression. Lead analogs restored receptor activity in loss-of-function PPARγ variants and improved insulin sensitivity in adipocytes from a diabetic patient. These findings elucidate mechanisms of non-covalent PPARγ modulation establishing a framework for developing safer, next-generation insulin sensitizers for metabolic disease therapy.