Fibrosis suppressive effect and mechanism of CaSR positive allosteric modulators/p-dioxanone copolymers

Fibroblast-to-myofibroblast transition (FMT) and resistance to apoptosis are central drivers of fibrosis. Here, we report that sustained release of Calcium Sensing Receptor (CaSR) positive allosteric modulators (L-Phe, L-Trp, and cinacalcet) from electrospun p-dioxanone copolymer membranes exerts potent, ligand-specific anti-fibrotic effects. All formulations activated Gq-coupled CaSR, evoking ER-Ca²⁺ release and IP₃ generation. Differential recruitment of Gi yielded distinct cAMP/ROS signatures: cinacalcet (strong Gi bias) lowered cAMP and ROS levels, and suppressed AP-1, collagen-I and α-SMA expression; L-Trp (intermediate Gi) left cAMP unchanged while elevating ROS and inflammatory markers but nonetheless inhibited proliferation; L-Phe (weak Gi) raised cAMP, reduced ROS and fibrotic markers. Molecular docking confirmed Gi-coupling potency: cinacalcet (-125.4 kJ mol⁻¹) > L-Trp (-101.7 kJ mol⁻¹) > L-Phe (-75.5 kJ mol⁻¹). In a rat intestinal-adhesion model, cinacalcet and L-Phe membranes prevented adhesions and collagen deposition, whereas L-Trp only inhibited proliferation. Thus, these findings indicate that CaSR ligands tune fibroblast fate via Gi-biased receptor conformations and that ligand electrospun membranes constitute a versatile materials platform for precision antifibrotic therapy.