Distinct patterns of transcriptional and epigenetic alterations characterize acute and chronic kidney injury.

Acute kidney injury (AKI) and chronic kidney disease (CKD) are considered early and late phases of a pathologic continuum of interconnected disease states. Although changes in gene expression patterns have recently been elucidated for the transition of AKI to CKD, the epigenetic regulation of key kidney injury related genes remains poorly understood. We used multiplex RT-qPCR, ChIP-qPCR and integrative analysis to compare transcriptional and epigenetic changes at renal disease-associated genes across mouse AKI and CKD models. These studies showed that: (i) there are subsets of genes with distinct transcriptional and epigenetically profiles shared by AKI and CKD but also subsets that are specific to either the early or late stages of renal injury; (ii) differences in expression of a small number of genes is sufficient to distinguish AKI from CKD; (iii) transcription plays a key role in the upregulation of both AKI and CKD genes while post-transcriptional regulation appears to play a more significant role in decreased expression of both AKI and CKD genes; and (iv) subsets of transcriptionally upregulated genes share epigenetic similarities while downregulated genes do not. Collectively, our study suggests that identified common transcriptional and epigenetic profiles of kidney injury loci could be exploited for therapeutic targeting in AKI and CKD.