Minoxidil Restores Thymic Growth in 22q11.2 Deletion Syndrome by Limiting Sox9+ Chondrocyte Expansion

The study investigates the effects of minoxidil on thymic growth in mouse models of 22q11.2 deletion syndrome (22q11.2DS), which causes thymic hypoplasia, hypoparathyroidism, and cardiac defects. Researchers found that embryonic thymuses in these models have an expansion of Sox9+ chondrocytes, affecting thymus size and vascularization. Administering minoxidil to pregnant mice before thymic development restored thymic growth and corrected mesenchymal and endothelial dysregulation. This was evidenced by reduced expression of Sox9-driven cartilaginous collagens and corrected parathyroid location. The findings suggest that targeting prenatal mesenchymal differentiation can address multiple congenital anomalies in 22q11.2DS mouse models.