Nitric Oxide and Lipid Peroxidation Valerie B ODonnella

Nitric Oxide and Lipid Peroxidation Valerie B. O’Donnella, Neil Hoggb and Victor M. Darley Usmarc a. Dept of Med. Biochem. University of Wales College of Medicine, Heath Park, Cardiff CF 14 4 XN, UK. Ph: 0044 -2920 -748447 Fax: 0044 -2920 -744905 Email: o-donnellvb@cardiff. ac. uk NO & LPO b. Biophysics Research Institute, Medical College of Wisconsin, Milwaukee, WI USA. c. Department of Pathology, University of Alabama at Birmingham, AL USA Society For Free Radical Biology and Medicine O’Donnell et al. 1

Nitric Oxide is a Free Radical N=O NO & LPO Society For Free Radical Biology and Medicine O’Donnell et al. 2

c Nitric oxide is not particularly oxidizing. Nitric oxide is (infinitely) stable*. Nitric oxide does not rapidly react with organic molecules. *In the absence of dioxygen. NO & LPO Society For Free Radical Biology and Medicine O’Donnell et al. 3

The Nitric Oxide ‘Radical’ and some of its stable end-products • N=O…nitric oxide -O-N=O…nitrite RO-N=O…alkyl nitrite RS-N=O…nitrosothiol NO & LPO Society For Free Radical Biology and Medicine O’Donnell et al. 4

Reactions of • NO with Other Free Radicals Oxidation of NO to nitrite: 4 NO+ O=O +2 H 2 O 4 HNO 2 Nitric oxide reaction with organic peroxyl radicals: NO+ NO & LPO ROONO ? ? Society For Free Radical Biology and Medicine O’Donnell et al. 5

Lipid Peroxidation LOO + LH + O 2 LOO + LOOH LOO is the central and rate-limiting species of lipid peroxidation NO & LPO Society For Free Radical Biology and Medicine O’Donnell et al. 6

LOOH Non-enzymatic lipid oxidation Metal or enzyme LOO AOO O 2 LH Initiation NO & LPO LH LH L O 2 L LOOH O 2 LOOH GPx LOH LOO GPx Propagation LOH Society For Free Radical Biology and Medicine Propagation O’Donnell et al. 7

Lipid peroxidation products in an atherosclerotic lesion are both enzymatically and nonenzymatically produced. Foam cell 15 -LOX Necrotic core lipid hydroxides, hydroperoxides, aldehydes, epoxides, ketones, ceroid, isoprostanes NO & LPO Society For Free Radical Biology and Medicine Fibrous cap O’Donnell et al. 8

Location of lipid oxidation enzymes in the vasculature LOX: lipoxygenase PGHS: prostaglandin H synthase Smooth muscle: 12 -LOX Endothelium PGHS-1 NO & LPO Monocyte: PGHS-1, 2 5, 15 -LOX Platelet: PGHS-1 12 -LOX Society For Free Radical Biology and Medicine Neutrophil: PGHS-1, 2 5, 12 -LOX O’Donnell et al. 9

Lipid oxidation enzymes are upregulated during vascular disease. * Inhibition of 12 -LOX restores blood pressure in Angiotensin. II dependent hypertensive rats. * Increased products of PGHS in hypertensive rats, and PGHS inhibition restores blood pressure in humans and rats. * Smooth muscle 12 -LOX in hypertension * Platelet 12 -LOX in hypertension * Foam cell/macrophage 15 -LOX in atherosclerosis. NO & LPO Society For Free Radical Biology and Medicine O’Donnell et al. 10

Nitric oxide reaction with lipid peroxyl radicals NO LOONO [LO NO 2] H 2 O LOOH + NO 2 - LO NO 2 NO LONO NO & LPO NO NO 2 Society For Free Radical Biology and Medicine [L(O) NO 2] L(O)NO 2 O’Donnell et al. 11

Reactions between NO-derived reactive nitrogen species and unsaturated lipid NO O 2 NO L(O)NO 2 LOONO O 2 - 2 L LH NO NO ONOO- & LPO O 2 , ONOO 2 LOO HONO LOOH e -, H + LNO 2 Society For Free Radical Biology and Medicine O’Donnell et al. 12

Nitric oxide inhibition of lipid oxidation coincides with fast rates of NO uptake during ABAP-dependent linoleate oxidation. (A) (B) Oxygen (µM) 0. 2 ABAP 100 -0. 2 [ NO] = 0. 9 µM added at vertical lines to 7. 3 m. M linoleate in 0. 5% cholate, 11 m. M ABAP 0 0 NO & LPO 400 800 Time/s Society For Free Radical Biology and Medicine -0. 6 1200 O’Donnell et al. 13 NO (µM) 0. 6 200

Mechanism of Inhibition of LDL Oxidation by NO LOO + NO LOONO LOOH LO + NO 2 LONO 2 OLOO + NO OLOONO OLONO 2 Two NO consumed for each LOO 4 NO + 2 LOO + H 2 O NO & LPO 2 HNO 2 + LONO Society For Free Radical Biology and Medicine O’Donnell et al. 14

Cholesteryl Ester Triglyceride Phospholipid Apolipoprotein B LH Oxidant O 2 LH LOO • O 2 • NO L • • NO 2 2 LNO 2 L • -Tocopherol LOOH • NO L(O)NO 2 Cholesterol • NO NO & LPO Society For Free Radical Biology and Medicine O’Donnell et al. 15

NO and LDL Oxidation: The effect of HPODE Lag time of LDL (125 g/ml) oxidation by Cu(II) (20 M) with and without HPODE (5 M) NO & LPO Society For Free Radical Biology and Medicine O’Donnell et al. 16

Comparison of nitric oxide and tocopherol inhibition of linoleate oxidation. ABAP [Oxygen]/µM 300 a -tocopherol (1 µM) NO 200 (1 µM) Tinh 100 Tinh 0 0 200 400 600 800 1000 1200 Time/s Oxidation of linoleate (7. 3 m. M) by ABAP (11 m. M) NO & LPO Society For Free Radical Biology and Medicine O’Donnell et al. 17

Nitric oxide is consumed by rabbit 15 -lipoxygenase during oxidation of linoleate. Add figure caption NO & LPO Society For Free Radical Biology and Medicine O’Donnell et al. 18

Site of lipoxygenase inhibition by NO & LPO Society For Free Radical Biology and Medicine O’Donnell et al. 19

Activation of LOX inhibits activation of s. GC by NO Lox NO s. GC c. GMP (% control) 100 50 ** 0 control NO & LPO AA, 5 µM LOX AA, 5 µM, LOX Society For Free Radical Biology and Medicine O’Donnell et al. 20

Further Reading: Darley-Usmar, VM et al. , (1992) Free Radic. Res. Commun. 17, 9 -20 Graham, A et al. , (1993) FEBS Lett. 330, 181 -185 Rubbo, H et al. , (1994) J. Biol. Chem. 265, 26066 -26075 Hogg, N et al. , (1995) J. Lipid Res. 36, 1756 -1762 Struck, N et al. , (1995) FEBS Lett 361, 291 -294 O’Donnell, VB et al. , (1997) Biochemistry 36, 15216 -15223 O’Donnell, VB et al. , (1999) Chem. Res. Toxicol. 12, 83 -92 O’Donnell, VB et al. , (1999) J. Biol. Chem. 274, 20083 -20091 Hogg, N & Kalyanaraman, B (1999) Biochim. Biophys. Acta. 1411, 378 -384 Rubbo, H et al. , (2000) J. Biol. Chem. 275, 10812 -10818 O’Donnell, VB & Freeman, BA (2001) Circ. Res. 88, 16 -25 NO & LPO Society For Free Radical Biology and Medicine O’Donnell et al. 21