Analyse oxidativer Stressinduktion in Fibroblasten und der Interaktion von Fibroblasten und Keratinozyten in einem 2-dimensionalen Modell der Atopischen Dermatitis

Evidence spreads that oxidative stress plays a role in the pathophysiology of Atopic Dermatitis (AD). As there is not much known about oxidative stress and the role of fibroblasts in AD, in vitro models of AD have been established and examined. AD-model fibroblasts exhibit elevated basal levels of intracellular oxidative stress compared to a control. Stress induction leads to even higher levels of reactive oxygen species (ROS) and AD-model fibroblasts react more sensitive to this treatment than control fibroblasts. By inhibiting nicotinamide adenine dinucleotide phosphate (NADPH)-oxidases the level of oxidative stress is reduced, therefore it can be assumed that fibroblasts produce ROS in response to oxidative stress which leads to a positive feedback cycle of ROS generation. The cell viability is not reduced in AD-model fibroblasts compared to a control, while it is reduced by the induction of oxidative stress. The induction of oxidative stress leads to DNA damage which can be abrogated by inhibiting NADPH oxidases. There is no difference in the extent of damage between AD-model and control fibroblasts. The ability of fibroblasts to cope with oxidative stress seems to be unaffected by AD. The induction of oxidative stress leads to an activation of both pro-apoptotic and pro-survival pathways and promotes inflammation. Crosstalk experiments showed that fibroblasts induce a stronger reaction towards oxidative stress in keratinocytes. Keratinocytes induce a stronger reaction towards oxidative stress in fibroblasts but in a more powerful way. In both cases the reaction could be suppressed by inhibiting NADPH oxidases, therefore it can be assumed that the reaction is mediated by NADPH oxidases. It can be assumed that both keratinocytes and fibroblasts secrete factors that prime the other cells to react more sensitive to subsequent oxidative stress and lead to a reinforcement of oxidative stress in neighbouring tissues

Nutrition-Based Modulation of Poly-ADP-Ribosylation and its possible role in Alzheimer’s disease

Alzheimer’s Disease (AD) is the most common neurodegenerative disease and the main reason of dementia in the elderly. On the pathological point of view, it is characterized by extracellular aggregates of amyloid peptides and intracellular deposits of tau protein. These deposits affect neuron viability and functions by inducing (among other pathological pathways) oxidative stress and triggering mitochondrial dysfunction. It is now evident that free radicalinduced oxidative damage is strongly involved in the pathogenesis of AD. Oxidative damage occurs early in disease pathogenesis and can exacerbate its progression. Post-mortem brain of individuals affected by AD, evidenced an extensive state of oxidative stress compared to healthy controls; markers of increased oxidation include, among others, DNA damage. DNA damage can induce the activity of the enzyme poly (ADP-ribose) polymerase 1 (PARP-1) that catalyze the reaction of poly (ADP-ribosylation). This post-translational modification modulates the functions of proteins involved in many physiological processes such as gene expression, maintenance of genomic stability and cell death. Therefore, inhibiting PARP-1 activity can represent a possible new strategy to reduce the impact of the oxidative stress in AD as well as in other neurodegenerative diseases. Here we discuss the role of nutrients in modulating PARP-1 activity and its perspective potential application

Surfactant Protein (SP) induces preterm birth by promoting oxidative stress via upregulating Storkhead-Box Protein 1

Preterm birth is the leading cause of infant mortality. The mechanisms that instigate preterm birth remain elusive and this makes it difficult to predict or prevent preterm birth. In this study, the authors found that SP-A induced pathological damage to the placenta and promoted preterm birth. Through mechanism, SP-A promoted the expression of STOX1 which further promoted the oxidative stress in the placenta by inhibiting the activities of a series of antioxidant enzymes including SOD, CAT and GSH-Px. SP-A also induced dysregulation of arginine metabolism by inhibiting NOS2 and ARG2. Overexpression of STOX1 aggravated SP-A induced oxidative stress, pathological damage, and preterm birth, whereas knockdown of STOX1 alleviated SP-A induced oxidative stress, pathological damage and preterm birth. The present study uncovers that SP-A induces preterm birth by promoting oxidative stress via upregulating STOX1, which provides new targets for the prediction and prevention of preterm birth

Reduction of Oxidative Stress and Storage Lesions (RCSL) in Red Blood Cells: Analysis of Ascorbic Acid (AA), N-Acetylcysteine amide (AD4), and Serotonin (5-HT)

Oxidative stress is a common occurrence in red blood cell (RBC) storage in blood banks throughout the world. Typically RBC units stored under routine standard protocol (stored in SAGM-CPD additive solution) can only be kept up to forty-two days for transfusion usage before being discarded. I am studying the effects of Ascorbic Acid (AA), N-acetylcysteine amide (AD4), and Serotonin or 5-hydroxytryptamine (5- HT) as additives in blood bank storage to find out if these additives can reduce storageinduced oxidative stress on red blood cells (RBCs), as well as to understand how potential blood storage additives can affect the shelf life of blood and post-transfusion recovery in patients. I conducted a literature review by studying various journal articles that examined metabolism to proteomics and the synergy of the different additives. These various additives significantly alleviated a range of signs of oxidative stress on RBCs including but not limited to replenishing glutathione (GSH), decreasing percent hemolysis, inhibiting the phospholipid rearrangement, and encouraging ATP production. By reducing these symptoms of oxidative stress, RBCs are able to last longer without any significant changes biochemically, and decrease the chances of post-transfusion complications such as Graft vs Host Disease (GVHD). The new additive solution could potentially increase the patient’s post-transfusion recovery rates as well as increase the shelf life of RBC storage units past the standard forty-two days

Fluoride Increases Superoxide Production and Impairs the Respiratory Chain in ROS 17/2.8 Osteoblastic Cells

It is known that fluoride produces oxidative stress. Inflammation in bone tissue and an impairment of the respiratory chain of liver have been described in treatments with fluoride. Whether the impairment of the respiratory chain and oxidative stress are related is not known. The aim of this work was to study the effects of fluoride on the production of superoxide radical, the function of the respiratory chain and the increase in oxidative stress in ROS 17/2.8 osteoblastic cells. We measured the effect of fluoride (100 mM) on superoxide production, oxygen consumption, lipid peroxidation and antioxidant enzymes activities of cultured cells following the treatment with fluoride. Fluoride decreased oxygen consumption and increased superoxide production immediately after its addition. Furthermore, chronic treatment with fluoride increased oxidative stress status in osteoblastic cells. These results indicate that fluoride could damage bone tissue by inhibiting the respiratory chain, increasing the production of superoxide radicals and thus of the others reactive oxygen speciesFil: Fina, Brenda. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Laboratorio de Biología Ósea; ArgentinaFil: Lombarte, Mercedes. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Laboratorio de Biología Ósea; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rigalli, Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Fisiología Experimental. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Fisiología Experimental; ArgentinaFil: Rigalli, Alfredo. Universidad Nacional de Rosario. Facultad de Ciencias Médicas. Laboratorio de Biología Ósea; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Extra Virgin Olive Oil Polyphenols Promote Cholesterol Efflux and Improve HDL Functionality

Results of the present work give evidence from the beneficial role of extra virgin olive of oil (EVOO) consumption towards oxidative stress and cardiovascular diseases. Polyphenols contained in EVOO are responsible for inhibiting lipoproteins oxidative damages and promoting reverse cholesterol transport process via ABCA1 pathway

How innate immunity proteins kill bacteria and why they are not prone to resistance

Recent advances on antibacterial activity of peptidoglycan recognition proteins (PGRPs) offer some insight into how innate immunity has retained its antimicrobial effectiveness for millions of years with no frequent emergence of resistant strains. First, PGRP can bind to multiple components of bacterial envelope (peptidoglycan, lipoteichoic acid, and lipopolysaccharide). Second, PGRP simultaneously induces oxidative, thiol, and metal stress responses in bacteria, which individually are bacteriostatic, but in combination are bactericidal. Third, PGRP induces oxidative, thiol, and metal stress responses in bacteria through three independent pathways. Fourth, antibacterial effects of PGRP are enhanced by other innate immune responses. Thus, emergence of PGRP resistance is prevented by bacteriostatic effect and independence of each PGRP-induced stress response, as PGRP resistance would require simultaneous acquisition of three separate mechanisms disabling the induction of all three stress responses. By contrast, each antibiotic has one primary target and one primary antibacterial mechanism, and for this reason resistance to antibiotics can be generated by inhibition of this primary mechanism. Manipulating bacterial metabolic responses can enhance bacterial killing by antibiotics and elimination of antibiotic-tolerant bacteria, but such manipulations do not overcome genetically encoded antibiotic resistance. Pathogens cause infections by evading, inhibiting, or subverting host immune responses

Protective Role of Kallistatin in Vascular Injury, Senescence and Aging

Kallistatin, a plasma protein, consists of two essential structural elements, an active site and a heparin-binding domain. Kallistatin exerts pleiotropic effects on angiogenesis, inflammation, fibrosis and tumor growth. This study aims to decipher the role and mechanism of kallistatin in vascular injury, senescence and aging. First, we determined the effect of kallistatin on endothelial-mesenchymal transition (EndMT), a process mediating vascular injury, organ fibrosis and cancer progression. Recombinant human kallistatin via its heparin-binding site blocked TGF-β-induced EndMT, associated with downregulated microRNA (miR)-21-Akt signaling and oxidative stress in human endothelial cells. Kallistatin’s active site is essential for stimulating antioxidant genes, endothelial nitric oxide synthase (eNOS) and sirtuin 1 (SIRT1) by interacting with a tyrosine kinase. These findings indicate that kallistatin suppresses EndMT by inhibiting miR-21-Akt signaling and oxidative stress. Secondly, we determined the role and mechanism of kallistatin in vascular senescence and aging. Kallistatin antagonized TNF- α-induced senescence and oxidative stress, and inhibited miR-34a, a senescence inducer, leading to elevated SIRT1/eNOS synthesis in human endothelial progenitor cells. Kallistatin administration in streptozotocin (STZ)-induced diabetic mice attenuated aortic senescence associated with reduced miR-34a and elevated SIRT1/eNOS levels. Consistently, kallistatin delayed stress-induced organismal aging in Caenorhabditis elegans by inhibiting miR-34 and elevating the longevity gene, sir-2.1 (SIRT1 homolog) synthesis. Therefore, kallistatin reduces vascular senescence and aging by inhibiting miR-34a-SIRT1/eNOS pathway. Thirdly, we determined the role of endogenous kallistatin in endothelial senescence, oxidative stress and inflammation by generating two strains of kallistatin knockout mice, endothelial cell-specific and general kallistatin knockout mice. Kallistatin via inducing an endo-protective miRNA Let-7g antagonized miR-34a-SIRT1-eNOS pathway and inhibited senescence, oxidative stress and inflammation in human endothelial cells. Conversely, kallistatin deficiency in mouse lung endothelial cells aggravated H2O2-induced senescence, oxidative stress and inflammation associated with downregulated Let-7g and antioxidant genes and upregulated miR-34a synthesis, indicating that kallistatin protects against endothelial senescence by modulating Let-7g mediated miR-34a-SIRT1-eNOS pathway. Moreover, systemic depletion of kallistatin exacerbated aortic oxidative stress and renal fibrosis in STZ-induced diabetic mice. These studies indicate that kallistatin plays a novel role in protection against vascular injury, senescence and aging by regulating Let-7g, miR-34a and miR-21 synthesis, and antioxidant gene expression

The Effects Of Stress On The Mammalian Nucleolus And Ribosome Synthesis

Ribosomes are responsible for translating every protein in the cell and are essential in all domains of life. Ribosome biosynthesis (RB) takes place in the nucleolus and is an intricate hierarchical process involving over 200 factors, including ribosomal proteins, ribosomal RNA (rRNA), and trans-acting ribosome biogenesis factors (RBFs). Inhibiting RB can disrupt nucleolar integrity, causing ribosomal- and nucleolar-factors to delocalize. This can stabilize the transcription factor p53, which is normally degraded rapidly, ultimately causing cell cycle arrest or apoptosis, through a mechanism termed the nucleolar stress response (NSR). This thesis explores the effects of inhibiting RB post rRNA transcription and discusses its role in human diseases. Using a dominate-negative RBF mutant, this work demonstrates that targeting RB after rRNA transcription is a viable approach to increase the efficacy of the chemotherapeutic agent camptothecin (CPT) against p53-negative cancers. Importantly, this model of targeting RB is independent of DNA damage, unlike currently developed molecular inhibitors of RB. In addition to exploring the combinational effects of CPT and post-transcriptional inhibition of RB, this thesis also investigated the impact of oxidative stress on nucleolar function. The onset of several diseases, including cancer and neurodegeneration, has been linked to both oxidative stress and nucleolar stress. However, very little has been reported on the effects of oxidative stress on the nucleolus. Using a newly generated nucleolar-specific redox sensor, this work demonstrates an increase in the oxidative state of the nucleolus and oxidative damage in nucleolar RNA when cells are challenged with a variety of chemical pro-oxidants. Additionally, rRNA processing and ribosomal subunit synthesis is inhibited by pro-oxidants. This phenotype was exacerbated when the antioxidant glutathione was depleted. The significance of this work demonstrates the susceptibility of the nucleolus to oxidative stress

Ceramide is a Mediator of Apoptosis in Retina Photoreceptors

PURPOSE. The precise mechanisms involved in photoreceptor apoptosis are still unclear. We here investigated the role of ceramide, a sphingolipid precursor that induces apoptosis upon cellular stress, in activating this death in photoreceptors. METHODS. Rat retina neuronal cultures, with or without docosahexaenoic acid (DHA), were treated with the ceramide analog acetylsphingosine (C2-ceramide), and with a glucosylceramide synthase inhibitor. Ceramide synthesis in cultures treated with the oxidant paraquat was evaluated with [3H]palmitate. The effect of inhibitors of ceramide de novo synthesis, fumonisin B1 and cycloserine, on photoreceptor apoptosis was investigated. Apoptosis, mitochondrial membrane potential and Bcl-2 expression were determined. RESULTS. Addition of C2-ceramide induced photoreceptor apoptosis. Paraquat increased formation of [3H]ceramide in photoreceptors, compared to controls, while inhibition of ceramide synthesis, immediately before paraquat treatment, prevented paraquat-induced photoreceptor apoptosis. Fumonisin also reduced photoreceptor apoptosis during early development in vitro. DHA, the retina major polyunsaturated fatty acid, which protects photoreceptors from oxidative stress-induced apoptosis, completely blocked C2-ceramide-induced photoreceptor death, simultaneously increasing Bcl-2 expression. Inhibiting glucosylceramide synthase, which catalyzes ceramide glucosylation, before ceramide or paraquat treatment blocked DHA protective effect. CONCLUSIONS. Our results suggest that oxidative stress stimulated an increase in ceramide levels, which induced photoreceptor apoptosis. DHA prevented oxidative stress and ceramide damage by up regulating Bcl-2 expression and glucosylating ceramide, thus decreasing its intracellular concentration. This shows for the first time that ceramide is a critical mediator for triggering photoreceptor apoptosis in mammalian retina and suggests that modulating ceramide levels might provide a therapeutic tool for preventing photoreceptor death in neurodegenerative diseases.Fil: German, Olga Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Miranda, Gisela Edit. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Abrahan, Carolina Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; ArgentinaFil: Rotstein, Nora Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Investigaciones Bioquímicas de Bahía Blanca. Universidad Nacional del Sur. Instituto de Investigaciones Bioquímicas de Bahía Blanca; Argentin