Loss of functional beta cell mass is a hallmark of both type 1 and type 2 diabetes. However, the mechanism that mediates this process has not been elucidated, and corresponding therapies have not been developed. MicroRNAs are ~ 22-nt small RNAs that mediate post-transcriptional regulation of gene expression. Dr. Xu found that diabetes induces the beta cell miR-204, which in turn represses insulin transcription by targeting and inhibiting the insulin transcription factor MAFA. His work also showed that miR-204 exacerbates ER stress-induced beta cell death by targeting the UPR protein PERK. His current work aims at inhibiting miR-204 to improve beta cell function and survival in the context of diabetes. In addition, Dr. Xu also works on developing strategies to halt beta cell loss in diabetes. He found that the anti-hypertension drug verapamil can prevent and even rescue beta cell apoptosis by targeting thioredoxin interacting protein (TXNIP) in the context of type 1 and type 2 diabetes. This study is currently in a phase II clinical trial.