The crosstalk between alternative splicing and histone ubiquitination modulates fast chemical reprogramming to pluripotency.

Cellular reprogramming has revolutionized regenerative medicine. Recently, we develop a fast chemical reprogramming (FCR) system; however, the underlying molecular mechanisms remain largely unknown. Here, we investigated the dynamics of RNA-binding protein (RBP) expression and alternative splicing (AS) events in the FCR system. We found that knockdown of AS regulator PTBP3 significantly enhanced FCR efficiency. Mechanistically, we identified that the PTBP3-SCMH1 axis regulated multiple downstream pathways, including inflammatory pathway. Pharmacological inhibition of inflammatory pathway using Amlexanox and BMS-345541 could further improve FCR efficiency. Collectively, our results highlight the essential role of AS in FCR and suggest that the crosstalk between AS and histone ubiquitination mediated by PTBP3-SCMH1 axis can be harnessed for modulating cell fates. These studies will help to better understand the fascinating question of how small molecules alone can rapidly induce pluripotency and provide new approaches for regeneration and rejuvenation.