Protection of cardiomyocytes from the hypoxia-mediated injury by a peptide targeting the activator of G-protein signaling 8.

ABSTRACT: Signaling via heterotrimeric G-protein is involved in the development of human diseases including ischemia-reperfusion injury of the heart. We previously identified an ischemia-inducible G-protein activator, activator of G-protein signaling 8 (AGS8), which regulates G?? signaling and plays a key role in the hypoxia-induced apoptosis of cardiomyocytes. Here, we attempted to intervene in the AGS8-G?? signaling process and protect cardiomyocytes from hypoxia-induced apoptosis with a peptide that disrupted the AGS8-G?? interaction. Synthesized AGS8-peptides, with amino acid sequences based on those of the G??-binding domain of AGS8, successfully inhibited the association of AGS8 with G??. The AGS8-peptide effectively blocked hypoxia-induced apoptosis of cardiomyocytes, as determined by DNA end-labeling and an increase in cleaved caspase-3. AGS8-peptide also inhibited the change in localization/permeability of channel protein connexin 43, which was mediated by AGS8-G?? under hypoxia. Small compounds that inhibit a wide range of G?? signals caused deleterious effects in cardiomyocytes. In contrast, AGS8-peptide did not cause cell damage under normoxia, suggesting an advantage inherent in targeted disruption of the AGS8-G?? signaling pathway. These data indicate a pivotal role for the interaction of AGS8 with G?? in hypoxia-induced apoptosis of cardiomyocytes, and suggest that targeted disruption of the AGS8-G?? signal provides a novel approach for protecting the myocardium against ischemic injury.

SUBMITTER: Sato M 

PROVIDER: S-EPMC3954831 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature