TY - JOUR A1 - Nowotny, Kerstin A1 - Castro, Jose Pedro A1 - Hugo, Martin A1 - Braune, Sabine A1 - Weber, Daniela A1 - Pignitter, Marc A1 - Somoza, Veronika A1 - Bornhorst, Julia A1 - Schwerdtle, Tanja A1 - Grune, Tilman T1 - Oxidants produced by methylglyoxal-modified collagen trigger ER stress and apoptosis in skin fibroblasts JF - Free radical biology and medicine : the official journal of the Oxygen Society, a constituent member of the International Society for Free Radical Research N2 - Methylglyoxal (MG), a highly reactive dicarbonyl, interacts with proteins to form advanced glycation end products (AGEs). AGEs include a variety of compounds which were shown to have damaging potential and to accumulate in the course of different conditions such as diabetes mellitus and aging. After confirming collagen as a main target for MG modifications in vivo within the extracellular matrix, we show here that MG-collagen disrupts fibroblast redox homeostasis and induces endoplasmic reticulum (ER) stress and apoptosis. In particular, MG-collagen-induced apoptosis is associated with the activation of the PERK-eIF2 alpha pathway and caspase-12. MG-collagen contributes to altered redox homeostasis by directly generating hydrogen peroxide and oxygen-derived free radicals. The induction of ER stress in human fibroblasts was confirmed using collagen extracts isolated from old mice in which MG-derived AGEs were enriched. In conclusion, MG-derived AGEs represent one factor contributing to diminished fibroblast function during aging. KW - Advanced glycation end products KW - Aging KW - Apoptosis KW - Collagen KW - ER stress KW - Methylglyoxal KW - Redox homeostasis Y1 - 2018 U6 - https://doi.org/10.1016/j.freeradbiomed.2018.03.022 SN - 0891-5849 SN - 1873-4596 VL - 120 SP - 102 EP - 113 PB - Elsevier CY - New York ER - TY - JOUR A1 - Henkel, Janin A1 - Coleman, Charles Dominic A1 - Schraplau, Anne A1 - Jöhrens, Korinna A1 - Weber, Daniela A1 - Castro, Jose Pedro A1 - Hugo, Martin A1 - Schulz, Tim Julius A1 - Krämer, Stephanie A1 - Schürmann, Annette A1 - Püschel, Gerhard Paul T1 - Induction of Steatohepatitis (NASH) with Insulin Resistance in Wild-type B6 Mice by a Western-type Diet Containing Soybean Oil and Cholesterol JF - Molecular medicine N2 - Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are hepatic manifestations of the metabolic syndrome. Many currently used animal models of NAFLD/NASH lack clinical features of either NASH or metabolic syndrome such as hepatic inflammation and fibrosis (e.g., high-fat diets) or overweight and insulin resistance (e.g., methionine-choline-deficient diets), or they are based on monogenetic defects (e.g., ob/ob mice). In the current study, a Western-type diet containing soybean oil with high n-6-PUFA and 0.75% cholesterol (SOD + Cho) induced steatosis, inflammation and fibrosis accompanied by hepatic lipid peroxidation and oxidative stress in livers of C57BL/6-mice, which in addition showed increased weight gain and insulin resistance, thus displaying a phenotype closely resembling all clinical features of NASH in patients with metabolic syndrome. In striking contrast, a soybean oil-containing Western-type diet without cholesterol (SOD) induced only mild steatosis but not hepatic inflammation, fibrosis, weight gain or insulin resistance. Another high-fat diet, mainly consisting of lard and supplemented with fructose in drinking water (LAD + Fru), resulted in more prominent weight gain, insulin resistance and hepatic steatosis than SOD + Cho, but livers were devoid of inflammation and fibrosis. Although both LAD + Fru-and SOD + Cho-fed animals had high plasma cholesterol, liver cholesterol was elevated only in SOD + Cho animals. Cholesterol induced expression of chemotactic and inflammatory cytokines in cultured Kupffer cells and rendered hepatocytes more susceptible to apoptosis. In summary, dietary cholesterol in the SOD + Cho diet may trigger hepatic inflammation and fibrosis. SOD + Cho-fed animals may be a useful disease model displaying many clinical features of patients with the metabolic syndrome and NASH. KW - Nonalcoholic Steatohepatitis (NASH) KW - Typical Western Diet KW - Nonalcoholic Fatty Liver Disease (NAFLD) KW - Dietary Cholesterol KW - Kupffer Cells Y1 - 2017 U6 - https://doi.org/10.2119/molmed.2016.00203 SN - 1076-1551 SN - 1528-3658 VL - 23 SP - 70 EP - 82 PB - Feinstein Inst. for Medical Research CY - Manhasset ER - TY - JOUR A1 - Reyes, Anibal M. A1 - Vazquez, Diego S. A1 - Zeida, Ari A1 - Hugo, Martin A1 - Dolores Pineyro, M. A1 - Ines De Armas, Maria A1 - Estrin, Dario A1 - Radi, Rafael A1 - Santos, Javier A1 - Trujillo, Madia T1 - PrxQ B from Mycobacterium tuberculosis is a monomeric, thioredoxin-dependent and highly efficient fatty acid hydroperoxide reductase JF - Free radical biology and medicine : the official journal of the Oxygen Society, a constituent member of the International Society for Free Radical Research N2 - Mycobacterium tuberculosis (M. tuberculosis) is the intracellular bacterium responsible for tuberculosis disease (TD). Inside the phagosomes of activated macrophages, M. tuberculosis is exposed to cytotoxic hydroperoxides such as hydrogen peroxide, fatty acid hydroperoxides and peroxynitrite. Thus, the characterization of the bacterial antioxidant systems could facilitate novel drug developments. In this work, we characterized the product of the gene Rv1608c from M. tuberculosis, which according to sequence homology had been annotated as a putative peroxiredoxin of the peroxiredoxin Q subfamily (PrxQ B from M. tuberculosis or MtPrxQ B). The protein has been reported to be essential for M. tuberculosis growth in cholesterol-rich medium. We demonstrated the M. tuberculosis thioredoxin B/C-dependent peroxidase activity of MtPrxQ B, which acted as a two-cysteine peroxiredoxin that could function, although less efficiently, using a one-cysteine mechanism. Through steady-state and competition kinetic analysis, we proved that the net forward rate constant of MtPrxQ B reaction was 3 orders of magnitude faster for fatty acid hydroperoxides than for hydrogen peroxide (3x10(6) vs 6x10(3) M-1 s(-1), respectively), while the rate constant of peroxynitrite reduction was (0.6-1.4) x10(6) M-1 s(-1) at pH 7.4. The enzyme lacked activity towards cholesterol hydroperoxides solubilized in sodium deoxycholate. Both thioredoxin B and C rapidly reduced the oxidized form of MtPrxQ B, with rates constants of 0.5x10(6) and 1x10(6) M-1 s(-1), respectively. Our data indicated that MtPrxQ B is monomeric in solution both under reduced and oxidized states. In spite of the similar hydrodynamic behavior the reduced and oxidized forms of the protein showed important structural differences that were reflected in the protein circular dichroism spectra. KW - Mycobacterium tuberculosis KW - Peroxiredoxin KW - Thioredoxin KW - Peroxynitrite KW - Fatty acid hydroperoxides KW - Thiol-dependent peroxidase KW - Peroxidatic and resolving cysteine Y1 - 2016 U6 - https://doi.org/10.1016/j.freeradbiomed.2016.10.005 SN - 0891-5849 SN - 1873-4596 VL - 101 SP - 249 EP - 260 PB - Elsevier CY - New York ER -