Chromatin accessibility dynamics dictate renal tubular epithelial cell response to injury

Renal tubular epithelial cells (TECs) can initiate an adaptive response to completely recover from mild acute kidney injury (AKI), whereas severe injury often leads to persistence of maladaptive repair and progression to kidney fibrosis. Through profiling of active DNA regulatory elements by ATAC-seq, we reveal widespread, dynamic changes in the chromatin accessibility of TECs after ischemia-reperfusion injury. We show that injury-specific domains of regulatory chromatin become accessible prior to gene activation, creating poised chromatin states to activate the consequent gene expression program and injury response. We further identify RXR alpha as a key transcription factor in promoting adaptive repair. Activation of RXR alpha by bexarotene, an FDA-approved RXR alpha agonist, restores the chromatin state and gene expression program to protect TECs against severe kidney injury. Together, our findings elucidate a chromatin-mediated mechanism underlying differential responses of TECs to varying injuries and identify RXR alpha as a therapeutic target of acute kidney injury. Renal tubular epithelial cells (TECs) can initiate an adaptive or maladaptive response after injuries of different severity. Here, the authors elucidate a chromatin-mediated mechanism underlying the responses of TECs to varying kidney injuries.