PDCD4 and polycystic ovary syndrome: Zhao et al. explored the impact of exosomal miR-323-3p from adipose mesenchymal stem cells (AMSCs) on cumulus cells (CCs) of polycystic ovary syndrome (PCOS) patients, finding that it inhibited apoptosis by targeting programmed cell death protein 4 (PDCD4) and alleviated PCOS (Zhao et al., 2019).