Browsing by Author "Pennanen, Christian"

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    Insulin Stimulates Mitochondrial Fusion and Function in Cardiomyocytes via the Akt-mTOR-NF kappa B-Opa-1 Signaling Pathway
    (AMER DIABETES ASSOC, 2014) Parra, Valentina; Verdejo, Hugo E.; Iglewski, Myriam; del Campo, Andrea; Troncoso, Rodrigo; Jones, Deborah; Zhu, Yi; Kuzmicic, Jovan; Pennanen, Christian; Lopez Crisosto, Camila; Jana, Fabian; Ferreira, Jorge; Noguera, Eduard; Chiong, Mario; Bernlohr, David A.; Klip, Amira; Hill, Joseph A.; Rothermel, Beverly A.; Abel, Evan Dale; Zorzano, Antonio; Lavandero, Sergio
    Insulin regulates heart metabolism through the regulation of insulin-stimulated glucose uptake. Studies have indicated that insulin can also regulate mitochondrial function. Relevant to this idea, mitochondrial function is impaired in diabetic individuals. Furthermore, the expression of Opa-1 and mitofusins, proteins of the mitochondrial fusion machinery, is dramatically altered in obese and insulin-resistant patients. Given the role of insulin in the control of cardiac energetics, the goal of this study was to investigate whether insulin affects mitochondrial dynamics in cardiomyocytes. Confocal microscopy and the mitochondrial dye MitoTracker Green were used to obtain three-dimensional images of the mitochondrial network in cardiomyocytes and L6 skeletal muscle cells in culture. Three hours of insulin treatment increased Opa-1 protein levels, promoted mitochondrial fusion, increased mitochondrial membrane potential, and elevated both intracellular ATP levels and oxygen consumption in cardiomyocytes in vitro and in vivo. Consequently, the silencing of Opa-1 or Mfn2 prevented all the metabolic effects triggered by insulin. We also provide evidence indicating that insulin increases mitochondrial function in cardiomyocytes through the Akt-mTOR-NFB signaling pathway. These data demonstrate for the first time in our knowledge that insulin acutely regulates mitochondrial metabolism in cardiomyocytes through a mechanism that depends on increased mitochondrial fusion, Opa-1, and the Akt-mTOR-NFB pathway.
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    Mitochondrial Dynamics: a Potential New Therapeutic Target for Heart Failure
    (EDICIONES DOYMA S A, 2011) Kuzmicic, Jovan; del Campo, Andrea; Lopez Crisosto, Camila; Morales, Pablo E.; Pennanen, Christian; Bravo Sagua, Roberto; Hechenleitner, Jonathan; Zepeda, Ramiro; Castro, Pablo F.; Verdejo, Hugo E.; Parra, Valentina; Chiong, Mario; Lavandero, Sergio
    Mitochondria are dynamic organelles able to vary their morphology between elongated interconnected mitochondrial networks and fragmented disconnected arrays, through events of mitochondrial fusion and fission, respectively. These events allow the transmission of signaling messengers and exchange of metabolites within the cell. They have also been implicated in a variety of biological processes including embryonic development, metabolism, apoptosis, and autophagy. Although the majority of these studies have been confined to noncardiac cells, emerging evidence suggests that changes in mitochondrial morphology could participate in cardiac development, the response to ischemia-reperfusion injury, heart failure, and diabetes mellitus. In this article, we review how the mitochondrial dynamics are altered in different cardiac pathologies, with special emphasis on heart failure, and how this knowledge may provide new therapeutic targets for treating cardiovascular diseases. Full English text available from: www.revespcardiol.org (C) 2011 Sociedad Espanola de Cardiologia. Published by Elsevier Espana, SI. All rights reserved.
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    The complex interplay between mitochondrial dynamics and cardiac metabolism
    (2011) Parra, Valentina; Verdejo Pinochet, Hugo; Del Campo, Andrea; Pennanen, Christian; Kuzmicic, Jovan; Iglewski, Myriam; Hill, Joséph A; Rothermel, Beverly A.; Lavandero, Sergio