Protein Kinase A Inhibition Epigenetically Silences Ren1

Abstract

RationaleRenin-expressing cells are myoendocrine cells crucial for survival which detect changes in blood pressure and release renin to maintain homeostasis. One of the pathways responsible for renin expression includes cAMP as a crucial factor. cAMP binds to subunits of protein kinase A (PKA), ultimately recruiting both CBP and p300. Binding to the cAMP-responsive element in the renin enhancer region thus amplifies renin transcription. ObjectiveTo evaluate transcriptomic and epigenomic changes occurring at the renin locus via cAMP pathway inhibition. Methods and ResultsWe treated As4.1 cells (a tumoral cell line that constitutively expresses renin) with the PKA inhibitor H89 (treated) or DMSO (control). We then performed independent ATAC-seq, scRNA-seq, and ChIP-seq for H3K27Ac and P300 binding on biological replicates of treated and control As4.1 cells. Ren1 expression is significantly reduced following PKA inhibition with a corresponding loss in H3K27Ac and P300 binding at the locus. A restricted set of nine genes with overlapping dynamically accessible regions, differential gene expression, and H3K27Ac and P300 binding were identified with roles among three primary renin regulatory paradigms. ConclusionsThe data suggests that cAMP pathway inhibition controls renin expression through a reduction not in accessibility alone, but via a switch from an active to poised state of epigenetic control, a shift towards a less differentiated cellular identity, and the disruption of not only cAMP, but baroreceptor and Notch mediated renin regulatory pathways.