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Lookup NU author(s): Damien Maggiorani,
Dr Joao Passos
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© 2018 The Anatomical Society and John Wiley & Sons Ltd. Cellular senescence, the irreversible cell cycle arrest observed in somatic cells, is an important driver of age-associated diseases. Mitochondria have been implicated in the process of senescence, primarily because they are both sources and targets of reactive oxygen species (ROS). In the heart, oxidative stress contributes to pathological cardiac ageing, but the mechanisms underlying ROS production are still not completely understood. The mitochondrial enzyme monoamine oxidase-A (MAO-A) is a relevant source of ROS in the heart through the formation of H2O2 derived from the degradation of its main substrates, norepinephrine (NE) and serotonin. However, the potential link between MAO-A and senescence has not been previously investigated. Using cardiomyoblasts and primary cardiomyocytes, we demonstrate that chronic MAO-A activation mediated by synthetic (tyramine) and physiological (NE) substrates induces ROS-dependent DNA damage response, activation of cyclin-dependent kinase inhibitors p21cip, p16ink4a, and p15ink4b and typical features of senescence such as cell flattening and SA-β-gal activity. Moreover, we observe that ROS produced by MAO-A lead to the accumulation of p53 in the cytosol where it inhibits parkin, an important regulator of mitophagy, resulting in mitochondrial dysfunction. Additionally, we show that the mTOR kinase contributes to mitophagy dysfunction by enhancing p53 cytoplasmic accumulation. Importantly, restoration of mitophagy, either by overexpression of parkin or inhibition of mTOR, prevents mitochondrial dysfunction and induction of senescence. Altogether, our data demonstrate a novel link between MAO-A and senescence in cardiomyocytes and provides mechanistic insights into the potential role of MAO-dependent oxidative stress in age-related pathologies.
Author(s): Manzella N, Santin Y, Maggiorani D, Martini H, Douin-Echinard V, Passos JF, Lezoualc'h F, Binda C, Parini A, Mialet-Perez J
Publication type: Article
Publication status: Published
Journal: Aging Cell
Print publication date: 01/10/2018
Online publication date: 12/07/2018
Acceptance date: 28/05/2018
ISSN (print): 1474-9718
ISSN (electronic): 1474-9726
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