Cardioprotection by adaptation to ischaemia augments autophagy in association with BAG-1 protein

Cardiovascular Research Center, University of Connecticut School of Medicine, Farmington, 06030-1110, USA.
Journal of Cellular and Molecular Medicine (Impact Factor: 4.01). 10/2008; 13(2):373-87. DOI: 10.1111/j.1582-4934.2008.00495.x
Source: PubMed

ABSTRACT Autophagy is an intracellular process in which a cell digests its own constituents via lysosomal degradative pathway. Though autophagy has been shown in several cardiac diseases like heart failure, hypertrophy and ischaemic cardiomyopathy, the role and the regulation of autophagy is still largely unknown. Bcl-2-associated athanogene (BAG-1) is a multifunctional pro-survival molecule that binds with Hsp70/Hsc70. In this study, myocardial adaptation to ischaemia by repeated brief episodes of ischaemia and reperfusion (I/R) prior to lethal I/R enhanced the expression of autophagosomal membrane specific protein light chain 3 (LC3)-II, and Beclin-1, a molecule involved in autophagy and BAG-1. Autophagosomes structures were found in the adapted myocardium through electron microscopy. Co-immunoprecipitation and co-immunofluorescence analyses revealed that LC3-II was bound with BAG-1. Inhibition of autophagy by treating rats with Wortmannin (15 microg/kg; intraperitoneally) abolished the ischaemic adaptation-induced induction of LC3-II, Beclin-1, BAG-1 and cardioprotection. Intramyocardial injection of BAG-1 siRNA attenuated the induction of LC3-II, and abolished the cardioprotection achieved by adaptation. Furthermore, hypoxic adaptation in cardiac myoblast cells induced LC3-II and BAG-1. BAG-1 siRNA treatment attenuated hypoxic adaptation-induced LC3-II and BAG-1, and abolished improvement in cardiac cell survival and reduction of cell death. These results clearly indicate that myocardial protection elicited by adaptation is mediated at least in part via up-regulation of autophagy in association with BAG-1 protein.

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    • "In mammals, autophagy can be induced by exogenous H 2 O 2 (Zhang et al., 2009) or internal ROS generated mainly from mitochondria (Chen et al., 2007; Scherz-Shouval et al., 2007; Moore, 2008; Azad et al., 2009). However, autophagy can serve to reduce ROS levels and reduce oxidative damage (Kaushik and Cuervo, 2006; Scherz- Shouval and Elazar, 2007; Gurusamy et al., 2009; Jain et al., 2010). "
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    ABSTRACT: Autophagy as a conserved catabolic pathway can respond to reactive oxygen species (ROS) and plays an important role in degrading oxidized proteins in plants under various stress conditions. However, how ROS regulates autophagy in response to oxidative stresses is largely unknown. Here, we show that autophagy-related protein 3 (ATG3) interacts with the cytosolic glyceraldehyde-3-phosphate dehydrogenases (GAPCs) to regulate autophagy in Nicotiana benthamiana plants. We found that oxidative stress inhibits the interaction of ATG3 with GAPCs. Silencing of GAPCs significantly activates ATG3-dependent autophagy, while overexpression of GAPCs suppresses autophagy in N. benthamiana plants. Moreover, silencing of GAPCs enhances N gene-mediated cell death and plant resistance against both incompatible pathogens Tobacco mosaic virus and Pseudomonas syringae pv tomato DC3000, as well as compatible pathogen P. syringae pv tabaci. These results indicate that GAPCs have multiple functions in the regulation of autophagy, hypersensitive response, and plant innate immunity. © 2015 American Society of Plant Biologists. All rights reserved.
    The Plant Cell 03/2015; 27(4). DOI:10.1105/tpc.114.134692 · 9.34 Impact Factor
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    • "Autophagy activation has been proposed as one mechanism of cardioprotection [15]. In isolated rat hearts, protection by ischemic preconditioning, i.e., brief episodes of coronary artery occlusion/reperfusion, was associated with enhanced myocardial expression of LC3-II, beclin-1 [16], and p62 [14] as well as with enhanced expression of parkin in the mitochondrial fraction [17]. Parkin is a requisite for autophagic removal of mitochondria [17]. "
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    PLoS ONE 06/2014; 9(5):e96567. DOI:10.1371/journal.pone.0096567 · 3.23 Impact Factor
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    • "Heart tissue samples were collected at the end of experiments, fixed in 2% buffered paraformaldehyde (pH 7.4), embedded and frozen in O.C.T. compound, and subjected to cryosectioning. The obtained specimens (5-μm cuts) were processed for immunofluorescence analysis as described previously [23]. Primary antibodies against Sirt3 (rabbit IgG from Santa Cruz Biotechnology, Inc), PARKIN (rabbit IgG from Abcam), Foxo3a (goat IgG from Abcam), PINK1 (goat IgG from Abcam), Tom20 (mouse IgG from Abcam), and LC3 (rabbit and goat IgG from Santa Cruz Biotechnology, Inc) were used with optimal dilution of 1 : 250. "
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