UNIGE document Scientific Article
previous document  unige:5299  next document
add to browser collection
Title

Angiotensin II and tumour necrosis factor alpha as mediators of ATP-dependent potassium channel remodelling in post-infarction heart failure

Authors
Isidoro Tavares, Nadia
Published in Cardiovascular research. 2009, vol. 83, no. 4, p. 726-36
Abstract AIMS: Angiotensin II (Ang II) and tumour necrosis factor alpha (TNFalpha) are involved in the progression from compensated hypertrophy to heart failure. Here, we test their role in the remodelling of ATP-dependent potassium channel (K(ATP)) in heart failure, conferring increased metabolic and diazoxide sensitivity. METHODS AND RESULTS: We observed increased expression of both angiotensinogen and TNFalpha in the failing rat myocardium, with a regional gradient matching that of the K(ATP) subunit Kir6.1 expression. Both angiotensinogen and TNFalpha expression correlated positively with Kir6.1 and negatively with Kir6.2 expression across the post-infarction myocardium. To further identify a causal relationship, cardiomyocytes isolated from normal rat hearts were exposed in vitro to Ang II or TNFalpha. We observed increased Kir6.1 and SUR subunit and reduced Kir6.2 subunit mRNA expression in cardiomyocytes cultured with Ang II or TNFalpha, similar to what was observed in failing hearts. In patch-clamp experiments, cardiomyocytes cultured with Ang II or TNFalpha exhibited responsiveness to diazoxide, in terms of both K(ATP) current and action potential shortening. This was not observed in untreated cardiomyocytes and resembles the diazoxide sensitivity of failing cardiomyocytes that also overexpress Kir6.1. Ang II exerted its effect through induction of TNFalpha expression, because TNFalpha-neutralizing antibody abolished the effect of Ang II, and in failing hearts, regional expression of angiotensinogen matched TNFalpha expression. Finally, Ang II and TNFalpha regulated K(ATP) subunit expression, possibly through differential expression of Forkhead box transcription factors. CONCLUSION: This study identifies Ang II and TNFalpha as mediators of the remodelling of K(ATP) channels in heart failure.
Keywords ATP-Binding Cassette Transporters/genetics/metabolismAction Potentials/drug effectsAngiotensin II/metabolism/pharmacologyAnimalsCells, CulturedDiazoxide/pharmacologyForkhead Transcription Factors/genetics/metabolismGene Expression/drug effectsHeart Failure/etiology/genetics/metabolismKATP Channels/genetics/metabolismMyocardial Infarction/complications/genetics/metabolismMyocytes, Cardiac/drug effects/metabolismPatch-Clamp TechniquesPotassium Channels, Inwardly Rectifying/genetics/metabolismRNA, Messenger/genetics/metabolismRatsReceptors, Drug/genetics/metabolismTumor Necrosis Factor-alpha/antagonists & inhibitors/metabolism/pharmacologyVentricular Remodeling/drug effects/genetics/physiology
Identifiers
PMID: 19460779
Full text
Article (Published version) (426 Kb) - document accessible for UNIGE members only Limited access to UNIGE
Appendix (1.6 MB) - document accessible for UNIGE members only Limited access to UNIGE
Other version: http://cardiovascres.oxfordjournals.org/content/83/4/726.long
Structures
Research group Biologie du myocarde (22)
Citation
(ISO format)
ISIDORO TAVARES, Nadia et al. Angiotensin II and tumour necrosis factor alpha as mediators of ATP-dependent potassium channel remodelling in post-infarction heart failure. In: Cardiovascular research, 2009, vol. 83, n° 4, p. 726-36. https://archive-ouverte.unige.ch/unige:5299

199 hits

0 download

Update

Deposited on : 2010-03-02

Export document
Format :
Citation style :