A novel small molecule derived from Lentinula edodes targets PRDX1 to inhibit RANKL-induced osteoclast differentiation and rescues the osteoporotic phenotype [PRDX KO]

Bone remodeling, crucial for skeletal integrity, involves osteoclasts and osteoblasts. Osteoclastogenesis, regulated by NFATc1, is activated by c-Fos and NF-κB signaling in response to RANKL. Excessive RANKL signaling contributes to bone loss pathology. Here we reveal denatonium as an inhibitor of RANKL-induced osteoclast differentiation through the p65 pathway. RNA-seq identified downregulated osteoclast-related genes. Affinity chromatography pinpointed 35 denatonium-interacting proteins, with PRDX1 showing specificity. PRDX1 deficiency led to osteoporosis with increased osteoclast activity and enhanced RANKL-induced osteoclast formation. Denatonium blocked PRDX1 lysosomal degradation, stabilizing PRDX1. Through transcription factor binding site analysis, p65 emerged as a major target suppressed by the denatonium-PRDX1 interaction. Chromatin immunoprecipitation confirmed that the denatonium-PRDX1 complex inhibited p65 enrichment at promoter regions critical for osteoclast differentiation. In an osteoporosis animal model, denatonium treatment restored bone health. This study uncovers denatonium's novel role in bone formation regulation by selectively targeting PRDX1, suggesting its potential in osteoporosis treatment.