Reversal of high-glucose-induced transcriptional and epigenetic memories through NRF2 pathway activation (RNA-seq).
Aims: Evaluate the genome-wide gene expression and epigenomic alterations caused by transient high glucose (HG) in endothelial cells (ECs), and to assess NRF2 pathway activation as a potential treatment for the diabetes-associated transcriptional memory. Methods and results: We exposed human umbilical vein endothelial cells (HUVEC) to three different glucose treatments: control (5.5 mM for 8 days), HG (30 mM for 8 days) and memory (5.5 mM for 4 days followed by 30 mM for 4 days). After these treatments we conducted a series of experiments, first we found that cells in the HG treatment had sustained alterations in both glycolytic and respiratory rates that persisted in the memory treatment, this without changes in proliferation or cell viability. Similarly, HG provoked substantial changes in the expression of genes belonging to pathways known to be impaired in diabetes, like the TGF-beta, TNF, foxO, p53 and NRF2 pathways, many of which were still present in memory. In addition, we found persistent changes in chromatin accessibility located mainly in non-promoter regions, some of which we identified as putative enhancer regions neighboring genes altered in memory. Finally, we demonstrated that activation of the NRF2 pathway through either NRF2 overexpression or sulforaphane treatment was able to substantially revert the glucose-induced transcriptional memory in ECs. Conclusions: Our results demonstrate that transient HG induces persistent changes in both the transcriptomic and chromatin accessibility profiles of ECs, and that pharmacological NRF2 pathway activation through sulforaphane supplementation is able to prevent and revert the glucose-induced transcriptional memory. Overall design: RNA-seq/ATAC-seq of human umbilical vein endothelial cells in three different treatments: 8 days in 5.5 mM glucose (control), 8 days in 30 mM glucose (high glucose) and 4 days in 30 mM glucose followed by 4 days in 5.5 mM glucose (memory). Additionally, to evaluate the role of NRF2 pathway activation in the high-glucose-induced transcriptional memory, we performed RNA-seq of HUVECs exposed to our high glucose or memory treatments that were either overexpressing NRF2 or incubated with 1 µM sulforaphane. Finally, to evaluate the role of NRF2 pathway activation in the high-glucose-induced epigenetic memory, we performed ATAC-seq of HUVECs exposed to our memory treatment plus supplementation with 1 µM sulforaphane.