Timed use of digoxin prevents heart ischemia-reperfusion injury through a REV-ERBα-UPS signaling pathway

ABSTRACT: Myocardial ischemia-reperfusion injury (MIRI) is a major threat to heart functional integrity and pharmacological means to achieve cardioprotection are sorely needed. The sequential hypoxic/normoxic status of the cardiac tissue triggers life-threatening damages through the activation of multiple intra-cellular pathways. Heart tolerance to MIRI varies according to a day-night cycle and is regulated by components of the molecular clock such as the transcriptional repressor and nuclear receptor REV-ERBα. Timed REV-ERBα antagonism alleviates sensitivity to myocardial infarction in mice. Here we show that timed administration of digoxin is cardioprotective by triggering REV-ERBα protein degradation. Kinomics and transcriptomic assays revealed that in several cardiomyocyte cellular models, digoxin and other cardiotonic steroids induced multiple signaling pathways. Pharmacological inhibition and knockdown approaches revealed that inhibition of the Src tyrosine-kinase partially alleviated digoxin-induced REV-ERBα degradation, which was fully prevented upon proteasome inhibition. REV-ERBα is increasingly ubiquitinylated in digoxin-treated cells, and its degradation depends on its ability to bind its natural ligand, heme. In unchallenged conditions, the proteasomal degradation of REV-ERBα is controlled by several known (HUWE1, FXW7, SIAH2) or novel (CBL, UBE4B)E3 ubiquitin ligases. Only SIAH2 together with the proteasome subunit PSMB5 were found tocontribute to the digoxin-induced degradation of REV-ERBα. Taken together, these results show that controlling REV-ERBα proteostasis is an appealing cardioprotective strategy, and bring further support to the rationale, timed use of CTS in prophylactic cardiac preconditioning to MIRI.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Agnès Hovasse  

LAB HEAD: Agnes Hovasse

PROVIDER: PXD036607 | Pride | 2022-09-13

REPOSITORIES: Pride