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SIRT1 Protects the Heart from ER Stress-Induced Injury by Promoting eEF2K/eEF2-Dependent Autophagy.

Cells (2020-02-16)
Julie Pires Da Silva, Kevin Monceaux, Arnaud Guilbert, Mélanie Gressette, Jérôme Piquereau, Marta Novotova, Renée Ventura-Clapier, Anne Garnier, Christophe Lemaire
RÉSUMÉ

Many recent studies have demonstrated the involvement of endoplasmic reticulum (ER) stress in the development of cardiac diseases and have suggested that modulation of ER stress response could be cardioprotective. Previously, we demonstrated that the deacetylase Sirtuin 1 (SIRT1) attenuates ER stress response and promotes cardiomyocyte survival. Here, we investigated whether and how autophagy plays a role in SIRT1-afforded cardioprotection against ER stress. The results revealed that protective autophagy was initiated before cell death in response to tunicamycin (TN)-induced ER stress in cardiac cells. SIRT1 inhibition decreased ER stress-induced autophagy, whereas its activation enhanced autophagy. In response to TN- or isoproterenol-induced ER stress, mice deficient for SIRT1 exhibited suppressed autophagy along with exacerbated cardiac dysfunction. At the molecular level, we found that in response to ER stress (i) the extinction of eEF2 or its kinase eEF2K not only reduced autophagy but further activated cell death, (ii) inhibition of SIRT1 inhibited the phosphorylation of eEF2, (iii) eIF2α co-immunoprecipitated with eEF2K, and (iv) knockdown of eIF2α reduced the phosphorylation of eEF2. Our results indicate that in response to ER stress, SIRT1 activation promotes cardiomyocyte survival by enhancing autophagy at least through activation of the eEF2K/eEF2 pathway.

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Description du produit

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Tamoxifène, ≥99%
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Triton X-100, laboratory grade
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Tunicamycine from Streptomyces sp.
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Chloroquine diphosphate salt, powder or crystals, 98.5-101.0% (EP)
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Anti-LC3B antibody produced in rabbit, ~1 mg/mL, affinity isolated antibody, buffered aqueous solution
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Fluorescein diacetate, used as cell viability stain
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N-éthylmaléimide, BioUltra, ≥99.0% (HPLC)
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3-Methyladenine, autophagy inhibitor
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EX-527, ≥98% (HPLC)
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Anti-Parkin antibody, Mouse monoclonal, clone PRK8, purified from hybridoma cell culture
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Durcupan ACM, set for 1 L embedding mixture
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eEF2K Inhibitor, A-484954, The eEF2K Inhibitor, A-484954, also referenced under CAS 142557-61-7, controls the biological activity of eEF2K Kinase. This small molecule/inhibitor is primarily used for Phosphorylation & Dephosphorylation applications.
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Anti-19S regulator non-ATPase subunit S5a/Rpn10 Antibody, clone S5a-18, clone S5a-18, Upstate®, from mouse