title: Vitamin C protects against hypochlorous Acid-induced glutathione depletion and DNA base and protein damage in human vascular smooth muscle cells.
abstract: Hypochlorous acid (HOCl), generated by myeloperoxidase released from activated macrophages, is thought to contribute to vascular dysfunction and oxidation of low density lipoproteins (LDLs) in atherogenesis. We have previously shown that HOCl exposure can cause chlorination and oxidation of isolated DNA and that vitamin C protects human arterial smooth muscle cells against oxidized LDL-mediated damage. We report in the present study that vitamin C attenuates HOCl-induced DNA base and protein damage and depletion of intracellular glutathione (GSH) and ATP in human arterial smooth muscle cells. Cells were pretreated in the absence or presence of 100 micromol/L vitamin C (24 hours) and then exposed to HOCl (0 to 500 micromol/L, 0 to 60 minutes) in the absence of vitamin C. Intracellular GSH and ATP levels were depleted by HOCl treatment, and gas chromatography-mass spectroscopy revealed a concentration- and time-dependent increase in DNA base oxidation and protein damage (measured as 3-chlorotyrosine). Pretreatment of smooth muscle cells with vitamin C significantly reduced the extent of HOCl-induced DNA and protein damage and attenuated decreases in intracellular ATP and GSH. Our findings suggest that physiological levels of vitamin C provide an important antioxidant defense against HOCl-mediated injury in atherosclerosis.
authors.affiliation: Centre for Cardiovascular Biology and Medicine, Guy's, King's and St. Thomas' School of Biomedical Sciences, King's College, University of London, London, UK.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Jenner
authors.forename: J Emilio
authors.initials: JE
authors.lastname: Ruiz
authors.forename: Christina
authors.initials: C
authors.lastname: Dunster
authors.forename: Barry
authors.initials: B
authors.lastname: Halliwell
authors.forename: Giovanni E
authors.initials: GE
authors.lastname: Mann
authors.forename: Richard C M
authors.initials: RC
authors.lastname: Siow
mesh_terms: D000255:Adenosine Triphosphate / Q000172:deficiency*; D001161:Arteriosclerosis / Q000378:metabolism; D001205:Ascorbic Acid / Q000494:pharmacology*; D002470:Cell Survival; D002478:Cells, Cultured; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D005978:Glutathione / Q000172:deficiency*; D006801:Humans; D006997:Hypochlorous Acid / Q000037:antagonists & inhibitors*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D014469:Umbilical Arteries / Q000187:drug effects / Q000378:metabolism
chemical_list: D006997:Hypochlorous Acid; D000255:Adenosine Triphosphate; D004247:DNA; D005978:Glutathione; D001205:Ascorbic Acid