CASP3 and mucopolysaccharidosis: Intriguingly, co-immunostaining for EMCN and c-Caspase-3 showed that RU486 treatment in mice significantly alleviated endothelial apoptosis in response to MPS treatment daily for 3 days, as shown by the reduction in c-Caspase3+ endothelial cells in the femoral heads of MPS-treated mice (Fig. S2m, n).