Browsing by Author "Fernandez, Samuel"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Lipopolysaccharide Activates Toll-Like Receptor 4 and Prevents Cardiac Fibroblast-to-Myofibroblast Differentiation
    (HUMANA PRESS INC, 2017) Bolivar, Samir; Santana, Roxana; Ayala, Pedro; Landaeta, Rodolfo; Boza, Pia; Humeres, Claudio; Vivar, Raul; Munoz, Claudia; Pardo, Viviana; Fernandez, Samuel; Anfossi, Renatto; Diaz Araya, Guillermo
    Bacterial lipopolysaccharide (LPS) is a known ligand of Toll-like receptor 4 (TLR4) which is expressed in cardiac fibroblasts (CF). Differentiation of CF to cardiac myofibroblasts (CMF) is induced by transforming growth factor-beta 1 (TGF-beta 1), increasing alpha-smooth muscle actin (alpha-SMA) expression. In endothelial cells, an antagonist effect between LPS-induced signaling and canonical TGF-beta 1 signaling was described; however, it has not been studied whether in CF and CMF the expression of alpha-SMA induced by TGF-beta 1 is antagonized by LPS and the mechanism involved. In adult rat CF and CMF, alpha-SMA, ERK1/2, Akt, NF-kappa beta, Smad3, and Smad7 protein levels were determined by western blot, TGF-beta isoforms by ELISA, and alpha-SMA stress fibers by immunocytochemistry. CF and CMF secrete the three TGF-beta isoforms, and the secretion levels of TGF-beta 2 was affected by LPS treatment. In CF, LPS treatment decreased the protein levels of alpha-SMA, and this effect was prevented by TAK-242 (TLR4 inhibitor) and LY294002 (Akt inhibitor), but not by BAY 11-7082 (NF-kappa beta inhibitor) and PD98059 (ERK1/2 inhibitor). TGF-beta 1 increased alpha-SMA protein levels in CF, and LPS prevented partially this effect. In addition, in CMF alpha-SMA protein levels were decreased by LPS treatment, which was abolished by TAK-242. Finally, in CF LPS decreased the p-Smad3 phosphorylation and increased the Smad7 protein levels. LPS treatment prevents the CF-to-CMF differentiation and reverses the CMF phenotype induced by TGF-beta 1, through decreasing p-Smad3 and increasing Smad7 protein levels.
  • Thumbnail Image
    Item
    The impact of the history of Jesus on the systematics of Chalcedon
    (PONTIFICIA UNIV CATOLICA CHILE, FACULTAD TEOLOGIA, 2011) Fernandez, Samuel
    This article aims to study some particular points of the development of patristic Christology up to Chalcedon, from a historical perspective, in order to show how the historical revelation of God in Jesus of Nazareth had an impact that brought about change in the system of thought. While Christology was gradually being established in the "back and forth" dialogue between the historical event and the thought categories, the purpose of this article is to show, above all, that the historical revelation had such an impact on the theological system that redefining its thought categories was required.