Atrogin-1 deficiency promotes cardiomyopathy and premature death via impaired autophagy

Zaglia, Tania; Milan, Giulia; Ruhs, Aaron; Franzoso, Mauro; Bertaggia, Enrico; Pianca, Nicola; Carpi, Andrea; Carullo, Pierluigi; Paterini, Paola; Sacerdoti, David; Sarais, Cristiano; Catalucci, Daniele; Krüger, Marcus; Mongillo, Marco; Sandri, Marco

doi:10.1172/jci66339

Cited by 123 publications

(120 citation statements)

References 60 publications

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“…However, there is evidence that autophagy is enhanced in various pathological conditions, including cardiac hypertrophy [35], cardiomyopathy [62], and heart failure. Our results revealed that 3MA reversed the increase of the diameter, volume, and protein content of H9c2 cells induced by apelin-13.…”

Section: Discussionmentioning

confidence: 99%

Apelin-13 promotes cardiomyocyte hypertrophy via PI3K-Akt-ERK1/2-p70S6K and PI3K-induced autophagy

Xie

Liu

Feng

et al. 2015

ABBS

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Apelin is highly expressed in rat left ventricular hypertrophy Sprague Dawley rat models, and it plays a crucial role in the cardiovascular system. The aim this study was to clarify whether apelin-13 promotes hypertrophy in H9c2 rat cardiomyocytes and to investigate its underlying mechanism. The cardiomyocyte hypertrophy was observed by measuring the diameter, volume, and protein content of H9c2 cells. The activation of autophagy was evaluated by observing the morphology of autophagosomes by transmission electron microscopy, observing the subcellular localization of LC3 by light microscopy, and detecting the membrane-associated form of LC3 by western blot analysis. The phosphatidylinositol 3-kinase (PI3K) signaling pathway was identified and the proteins expression was detected using western blot analysis. The results revealed that apelin-13 increased the diameter, volume, and protein content of H9c2 cells and promoted the phosphorylation of PI3K, Akt, ERK1/2, and p70S6K. Apelin-13 activated the PI3K-Akt-ERK1/2-p70S6K pathway. PI3K inhibitor LY294002, Akt inhibitor 1701-1, ERK1/2 inhibitor PD98059 attenuated the increase of the cell diameter, volume, protein content induced by apelin-13. Apelin-13 increased the autophagosomes and up-regulated the expressions of beclin 1 and LC3-II/I both transiently and stably. The autophagy inhibitor 3MA ameliorated the increase of cell diameter, volume, and protein content that were induced by apelin-13. These results suggested that apelin-13 promotes H9c2 rat cardiomyocyte hypertrophy via PI3K-Akt-ERK1/2-p70S6K and PI3K-induced autophagy.

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Section: Discussionmentioning

confidence: 99%

Apelin-13 promotes cardiomyocyte hypertrophy via PI3K-Akt-ERK1/2-p70S6K and PI3K-induced autophagy

Xie

Liu

Feng

et al. 2015

ABBS

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“…23 Previous studies using animal models provided evidence for exercise-induced autophagy in muscle to maintain energy and nutrient supply. [24][25][26][27][28][29] A prominent example is the BCL2-regulated autophagy pathway that is essential for glucose homeostasis in skeletal and cardiac muscles of mice. 29 It remains to be seen whether this pathway is linked to CASA, in particular because the CASA-inducing cochaperone BAG3 belongs to a family of BCL2-interacting proteins and modulates the interaction of BCL2 with BECN1.…”

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confidence: 99%

Induction and adaptation of chaperone-assisted selective autophagy CASA in response to resistance exercise in human skeletal muscle

et al. 2015

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“…Protein degradation and clearance of damaged organelles are critical for cellular physiology, and failure in proper clearance has been shown to have pathological repercussions (9). Autophagy is a major mechanism that mediates protein and organelle degradation in response to external and internal signals.…”

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confidence: 99%

Metformin increases degradation of phospholamban via autophagy in cardiomyocytes

Teng

Miyake

Yokoe

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Phospholamban (PLN) is an effective inhibitor of the sarco(endo) plasmic reticulum Ca 2+ ATPase (SERCA). Here, we examined PLN stability and degradation in primary cultured mouse neonatal cardiomyocytes (CMNCs) and mouse hearts using immunoblotting, molecular imaging, and [ 35 S]methionine pulse-chase experiments, together with lysosome (chloroquine and bafilomycin A1) and autophagic (3-methyladenine and Atg5 siRNA) antagonists. Inhibiting lysosomal and autophagic activities promoted endogenous PLN accumulation, whereas accelerating autophagy with metformin enhanced PLN degradation in CMNCs. This reduction in PLN levels was functionally correlated with an increased rate of SERCA2a activity, accounting for an inotropic effect of metformin. Metabolic labeling reaffirmed that metformin promoted wild-type and R9C PLN degradation. Immunofluorescence showed that PLN and the autophagy marker, microtubule light chain 3, became increasingly colocalized in response to chloroquine and bafilomycin treatments. Mechanistically, pentameric PLN was polyubiquitinylated at the K3 residue and this modification was required for p62-mediated selective autophagy trafficking. Consistently, attenuated autophagic flux in HECT domain and ankyrin repeat-containing E3 ubiquitin protein ligase 1-null mouse hearts was associated with increased PLN levels determined by immunoblots and immunofluorescence. Our study identifies a biological mechanism that traffics PLN to the lysosomes for degradation in mouse hearts.selective autophagy | ubiquitinylation | protein degradation P hospholamban (PLN) is a 52-amino acid peptide located in the sarcoplasmic reticulum (SR) membrane in cardiac, slowtwitch skeletal, and smooth muscle, where it exists as a monomer or pentamer. Whereas monomeric PLN physically interacts with sarco(endo)plasmic reticulum Ca 2+ ATPase type 2a (SERCA2a) to antagonize its function, pentameric PLN complexes are thought to be a reservoir of inactive PLN (1-3). The physical interaction between SERCA2a and PLN reduces the apparent affinity of SERCA2a for Ca 2+ , thereby making SERCA2a less active in transporting Ca 2+ from the cytoplasm to the lumen of the SR at the same concentration of cytoplasmic Ca 2+. The physical interaction between the two proteins is regulated by phosphorylation of PLN at Ser16 by protein kinase A or at Thr17 by Ca 2+ /calmodulin-dependent protein kinase II (2). Phosphorylation of PLN reduces its affinity for SERCA2a, thereby increasing SERCA2a activity (2). Evidence from transgenic mice also supports the inhibitory function of PLN. Although targeted PLN deletion enhances baseline cardiac performance, cardiac-specific overexpression of superinhibitory forms of PLN leads to decreases in the affinity of SERCA2a for Ca 2+ (2). These observations underscore the primary role of PLN as a regulator of SERCA2a activity and, therefore, as a crucial regulator of cardiac contractility. PLN inhibition of SERCA2a can be reversed by either external (i.e., activation of β-adrenergic receptors) or internal (i.e., increased...

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Atrogin-1 deficiency promotes cardiomyopathy and premature death via impaired autophagy

Cited by 123 publications

References 60 publications

Apelin-13 promotes cardiomyocyte hypertrophy via PI3K-Akt-ERK1/2-p70S6K and PI3K-induced autophagy

Apelin-13 promotes cardiomyocyte hypertrophy via PI3K-Akt-ERK1/2-p70S6K and PI3K-induced autophagy

Induction and adaptation of chaperone-assisted selective autophagy CASA in response to resistance exercise in human skeletal muscle

Metformin increases degradation of phospholamban via autophagy in cardiomyocytes

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