Person:
Bragado Domingo, Paloma

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First Name
Paloma
Last Name
Bragado Domingo
URI
https://hdl.handle.net/20.500.14352/77645
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Farmacia
Department
Bioquímica y Biología Molecular
Area
Bioquímica y Biología Molecular
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2012 - 20132
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Author: Bragado Domingo, Paloma × Author: Gutiérrez Uzquiza, Álvaro × End date: 2021 × Item Type: Publication ×

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    Met signaling in cardiomyocytes is required for normal cardiac function in adult mice
    (Biochimica et Biophysica Acta (Molecular Basis of disease), 2013) Arechederra Calderón, María; Carmona Mejías, Rita; González-Nuñez, María; Gutiérrez Uzquiza, Álvaro; Bragado Domingo, Paloma; Cruz-González, Ignacio; Cano Rincón, Elena; Guerrero Arroyo, María Del Carmen; Sánchez Muñoz, Aranzazu; López-Novoa, José Miguel; Schneider, Michael D.; Maina, Flavio; Muñoz-Chápuli, Ramón; Porras Gallo, María Almudena
    Hepatocyte growth factor (HGF) and its receptor, Met, are key determinants of distinct developmental processes. Although HGF exerts cardio-protective effects in a number of cardiac pathologies, it remains unknown whether HGF/Met signaling is essential for myocardial development and/or physiological function in adulthood. We therefore investigated the requirement of HGF/Met signaling in cardiomyocyte for embryonic and postnatal heart development and function by conditional inactivation of the Met receptor in cardiomyocytes using the Cre-α-MHC mouse line (referred to as α-MHCMet-KO). Although α-MHCMet-KO mice showed normal heart development and were viable and fertile, by 6 months of age, males developed cardiomyocyte hypertrophy, associated with interstitial fibrosis. A significant upregulation in markers of myocardial damage, such as β-MHC and ANF, was also observed. By the age of 9 months, α-MHCMet-KO males displayed systolic cardiac dysfunction. Mechanistically, we provide evidence of a severe imbalance in the antioxidant defenses in α-MHCMet-KO hearts involving a reduced expression and activity of catalase and superoxide dismutase, with consequent reactive oxygen species accumulation. Similar anomalies were observed in females, although with a slower kinetics. We also found that Met signaling down-regulation leads to an increase in TGF-β production and a decrease in p38MAPK activation, which may contribute to phenotypic alterations displayed in α-MHCMet-KO mice. Consistently, we show that HGF acts through p38α to upregulate antioxidant enzymes in cardiomyocytes. Our results highlight that HGF/Met signaling in cardiomyocytes plays a physiological cardio-protective role in adult mice by acting as an endogenous regulator of heart function through oxidative stress control.
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    p38α Mediates Cell Survival in Response to Oxidative Stress via Induction of Antioxidant Genes
    (Journal of Biological Chemistry, 2012) Gutiérrez Uzquiza, Álvaro; Arechederra, María; Bragado Domingo, Paloma; Aguirre-Ghiso, Julio A.; Porras Gallo, María Almudena
    We reveal a novel pro-survival role for mammalian p38α in response to H(2)O(2), which involves an up-regulation of antioxidant defenses. The presence of p38α increases basal and H(2)O(2)-induced expression of the antioxidant enzymes: superoxide-dismutase 1 (SOD-1), SOD-2, and catalase through different mechanisms, which protects from reactive oxygen species (ROS) accumulation and prevents cell death. p38α was found to regulate (i) H(2)O(2)-induced SOD-2 expression through a direct regulation of transcription mediated by activating transcription factor 2 (ATF-2) and (ii) H(2)O(2)-induced catalase expression through regulation of protein stability and mRNA expression and/or stabilization. As a consequence, SOD and catalase activities are higher in WT MEFs. We also found that this p38α-dependent antioxidant response allows WT cells to maintain an efficient activation of the mTOR/p70S6K pathway. Accordingly, the loss of p38α leads to ROS accumulation in response to H(2)O(2), which causes cell death and inactivation of mTOR/p70S6K signaling. This can be rescued by either p38α re-expression or treatment with the antioxidants, N-acetyl cysteine, or exogenously added catalase. Therefore, our results reveal a novel homeostatic role for p38α in response to oxidative stress, where ROS removal is favored by antioxidant enzymes up-regulation, allowing cell survival and mTOR/p70S6K activation.