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β‐Arrestin‐Biased β2‐Adrenergic Receptor Signaling Provides Cardioprotection in Ischemia/Reperfusion Injury
Author(s) -
Grisanti Laurel A,
Lucia Claudio,
Gao Erhe A,
Koch Walter J,
Benovic Jeffrey L,
Tilley Douglas G
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1069.4
Subject(s) - cardioprotection , contractility , cardiac function curve , medicine , receptor , ischemia , tunel assay , reperfusion injury , endocrinology , pharmacology , cardiology , heart failure , immunohistochemistry
β‐Adrenergic receptors (βAR) are important regulators of cardiac function in the normal and failing heart. Activation of the β1AR subtype increases contractility and cardiomyocyte death whereas the β2AR can promote survival. In response to cardiac injury, increased catecholamines activate and downregulate β1AR thus, β‐adrenergic receptor antagonists or β‐blockers are commonly prescribed in to restore β1AR expression and preserve contractility. However, promoting the pro‐survival effects of β2AR, which are known to occur in part through β‐arrestin (ARR)‐dependent signaling, may be a beneficial therapeutic strategy. Pepducins have been developed based on the intracellular loop (ICL) domains of β2AR to activate either Gαs‐ or βARR‐dependent β2AR signaling pathways. We hypothesized that pepducin‐mediated engagement of βARR‐dependent β2AR signaling in the heart would be therapeutically advantageous following ischemia/reperfusion (I/R) injury. To test this, wild‐type (WT) C57BL/6 mice received three intracardiac injections of either a βARR‐biased pepducin (ICL1‐9) or a scrambled control pepducin at the time of ischemia (30 min) followed by reperfusion. Assessment of cardiomyocyte death 24h post‐I/R using TUNEL staining showed a decrease in cell death in animals treated with ICL1‐9 when compared to scrambled pepducin, correlating with decreased infarct size and improved cardiac function as measured by echocardiography. Assessment of cardiac function at later time points showed that the cardioprotective effects of ICL1‐9 were preserved over time and resulted in decreased cardiac remodeling. Although βARR1KO mice displayed similar cell death, infarct size, and contractility changes following I/R as their WT counterparts, they did not manifest a cardioprotective response from ICL1‐9 treatment, indicating that βARR signaling is essential in relaying ICL1‐9‐dependent cardioprotection. These results demonstrate that pharmacologically‐mediated activation of βARR‐biased β2AR signaling provides a therapeutic benefit in the context of I/R‐induced injury and may provide an improved strategy for the treatment of acute cardiac injury. Support or Funding Information NIH‐HL‐105414‐DGT