Impact of All-trans Retinoic Acid on Skeletal Development: Mechanisms of Growth Plate Closure

All-trans retinoic acid (ATRA), a therapeutic mainstay for acute promyelocytic leukemia, is associated with off-target effects on skeletal development, including premature growth plate closure. However, the molecular mechanisms underlying ATRA-induced growth plate senescence remain poorly understood.

Using Sprague-Dawley rats, ADTC5 chondrocyte cell lines, and integrated multiomics approaches (transcriptome sequencing, weighted gene co-expression network analysis, molecular docking, and functional assays), we investigated how ATRA modulates growth plate development. Animal models were treated with graded ATRA doses, while in vitro studies included cell viability assays, RNA interference, and Western blot analysis to validate interactions in the signaling pathway.

ATRA induced dose-dependent growth plate thinning (high-dose: 59.79 μm vs. control: 511.35 μm) and skeletal growth retardation in rats. Transcriptomic analysis identified ITGB2 as a pivotal gene, with molecular docking revealing a strong binding interaction (-240.25 kcal/mol) between ITGB2 and YAP mediated by hydrogen bonds/salt bridges. Functional experiments revealed that ATRA upregulated ITGB2, which activated YAP, a Hippo pathway effector, thereby suppressing Wnt/β-catenin signaling by inhibiting β-catenin. This led to downregulation of osteogenic markers (Runx2/SOX9) and enhanced growth plate closure. YAP knockdown reversed these effects, restoring β-catenin and downstream target gene expression (c-myc, cyclin D).

ATRA accelerates growth plate closure through the ITGB2-YAP axis, disrupting Wnt/β-catenin signaling. These findings establish a mechanistic framework for developing therapeutic strategies targeting ITGB2 or YAP to delay premature growth plate senescence in pediatric disorders.