Galactose-modified small molecule modulator targets RORα to enhance circadian rhythm and alleviate...

Circadian rhythm disorders are associated with dysfunction in inflammatory diseases, and targeted regulation of the circadian rhythm could serve as an intervention strategy. RORα/γ, as core components of circadian clock genes, positively modulate the key circadian molecule BMAL1. In this study, Gala-SR, a potent small-molecule compound designed to effectively regulate circadian rhythms, was synthesized through a monosaccharide modification prodrug strategy via a hydrolysable conjugation of galactose onto SR1078, an unique synthetic agonist of RORα/γ. Compared with SR1078, Gala-SR exhibited significantly greater aqueous solubility, cytocompatibility, pharmacokinetic characteristics and efficacy in the targeted activation of RORα. Importantly, Gala-SR ameliorated rhythm disorders by enhancing amplitude of the circadian rhythm both in vitro and in vivo. In circadian rhythm disordered mice with periodontitis, Gala-SR restored local circadian rhythm and mitigated inflammation in periodontal tissue in a circadian clock-dependent manner, and alleviated alveolar bone loss. Our study demonstrates that Gala-SR exhibits great promise in restoration of circadian rhythm and could potentially serve as a targeted therapeutic intervention for treating inflammatory diseases arising from disruptions in circadian rhythm. This work provides a feasible paradigm for the development and translational application of small molecule modulators targeting circadian rhythms.