PDCD4 and erectile dysfunction: For example, bone marrow-derived stem cells (BMSCs) treated with miR-21-5p-agomir resulted in the increase of miR-21-5p in BMSC-derived exosomes, which decreased the expression of target gene programmed cell death 4 (PDCD4) in CCSMCs, attenuating the erectile dysfunction through leading to the proliferation and apoptosis inhibition of these cells (53).