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Methods to Quantify Nitric Oxide en vivo: Concepts and Considerations R.

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Presentation on theme: "Methods to Quantify Nitric Oxide en vivo: Concepts and Considerations R."— Presentation transcript:

1 Methods to Quantify Nitric Oxide en vivo: Concepts and Considerations R

2 Atmospheric Nitrogen Oxides Los Angeles

3 Nitric Oxide N O Colorless Gas Free Radical Potent Vasodilator (EDRF)

4 NH NH 3 H 2 N + NH 3 NH N-OHH 2 N NH 3 NH O H 2 N NH 3 - OOC + NO NO Production by Nitric Oxide Synthase O2O2 NADPH O2O2 0.5 NADPH L-Arginine N G -Hydroxy-L-ArginineL-Citrulline

5 Nitric Oxide Synthase (NOS) Isoenzymes NOS Constitutive Inducible inducible NOS (iNOS; NOS 2) neuronal NOS (nNOS; NOS 1) endothelial NOS (eNOS; NOS 3)

6 Nitric Oxide is a Pleiotropic Regulator of the Immune, Cardiovascular and Nervous Systems

7 The Chemistry of Nitric Oxide Dictates its Physiological Activity Oxidation RNOS Guanylate Cyclase Cytochromes Lipid Radicals IRP-1 Ribonucleotide reductase O 2 or O 2 - Direct Indirect L-Arginine eNOS nNOS iNOS NO Nitrosation DNA Strand Breaks Lipid Peroxidation Hydroxylation Nitrosothiols Nitrosamines Nitrotyrosine Nitroguanosine Nitration Metal Complexes/Alkyl Radicals

8 Methods to Quantify NO and its Metabolites in Extracellular Fluids and/or Tissue ● Gas Phase Chemiluminescence (NO) ● Spectrophotometric Assays for Oxidized Metabolites of NO (Nitrite/Nitrate) Griess Assay Fluorescence Assay DAF-2 Bio-imaging ● Spectrophotometric Assays for RSNOs Saville Assay Modified Saville Assay

9 Methods to Quantify NO and its Metabolites in Extracellular Fluids and/or Tissue ● Gas Phase Chemiluminescence (NO) ● Spectrophotometric Assays for Oxidized Metabolites of NO (Nitrite/Nitrate) Griess Assay Fluorescence Assay DAF-2 Bio-imaging ● Spectrophotometric Assays for RSNOs Saville Assay Modified Saville Assay

10 NO Detection by Gas Phase Chemiluminescence Detection Principle: NO is purged from an aqueous solution using an innert gas such as Ar or He and transferred to a mixing chamber where it reacts with O 3 under reduced pressure. NO + O 3 NO 2 * + O 2 NO 2 * NO 2 + h.  The light emitted by excited NO 2 upon returning to the ground state is measured by photon counting (fmol-pmol). Not very useful when attempting to quantify NO in physiological fluids such as serum, plasma or urine. Why?

11 Autoxidation of NO 2NO + O 2 2NO 2 2NO + 2NO 2 2N 2 O 3 2N 2 O 3 + H 2 O 4NO H + 4NO + O 2 + 2H 2 O 4NO H +

12 Methods to Quantify NO and its Metabolites in Extracellular Fluids and/or Tissue ● Gas Phase Chemiluminescence (NO) ● Spectrophotometric Assays for Oxidized Metabolites of NO (Nitrite/Nitrate) Griess Assay Fluorescence Assay DAF-2 Bio-imaging ● Spectrophotometric Assays for RSNOs Saville Assay Modified Saville Assay

13 H 2 NSO 3 NN NO + H 2 NSO 3 NH Sulfanilamide NHNH 2 N-(1-Naphthyl)ethylenediamine Griess Reaction NHNH 2 NNH 2 N S O 3 Azo Dye ( max = 540 nm) NO 2 - +H +

14 Although Nitrite is Produced from NO Autoxidation, Nitrate is the Major NO-Derived Metabolite in Plasma and Urine: Role of Hemoglobin 2Hb-Fe +2 O 2 + 3NO H + 2Hb-Fe NO H 2 O 4Hb-Fe +2 O 2 + 4NO H + 4Hb-Fe NO O 2 + 2H 2 O Hb-Fe +2 O 2 + NO Hb-Fe +3 + NO 3 -

15 Quantification of NO-Derived NO 3 - and NO 2 - in Extracellular Fluids NO FAD + NADPH NO NADP + NR Nitrate Reductase (NR) Converts all NO 3 - to NO 2 - All unreacted NADPH must be oxidized NO 2 - quantified by Griess Reaction Grisham, M.B. et.al Quantitation of nitrate and nitrite in extracellular fluids. Methods Enzymol :

16 LPS Induces Nitric Oxide Production In Vivo Serum Nitrate and Nitrite (µM) * Saline +LPS Grisham et. al. Meth Enz, 1996

17 Measurement of NO 2 - /NO 3 - in Plasma Using the Griess Reagent: Problems and Considerations Heparin may produce precipitant upon addition of Griess Reagent. Addition of protamine sulfate will remove heparin (Suggestion: Use serum or calcium chelators such as EDTA or citrate). NO 2 - /NO 3 - may be underestimated in hemolyzed plasma or Serum due to Hb-catalyzed oxidation of NO 2 - (Suggestion: Ultrafilterplasma or serum to obtain a low molecular weight fraction; < 15,000). The presence of some plasma or serum-associated proteins may inhibit nitrate reductase (Suggestion: Ultrafilter plasma or serum to obtain a low molecular weight fraction).

18 Simultaneous Quantification of Nitrite and Nitrate by HPLC Using the Griess Reaction Sensitivity: 1 pmol/ml for either anion (injection volume 100µl) No interference by proteins or colored species 100 nM NO nM NO 3 - Rodriguez and Feelisch PNAS 100:336, 2003

19 Sources of NO 2 - /NO 3 - in Extracellular Fluids (Blood, Lymph, Urine, Saliva): NO Bacteria (Enteric; Oral) Diet (need for fasting or nitrate/ nitrite-free chow)

20 Methods to Quantify NO and its Metabolites in Extracellular Fluids and/or Tissue ● Gas Phase Chemiluminescence (NO) ● Spectrophotometric Assays for Oxidized Metabolites of NO (Nitrite/Nitrate) Griess Assay Fluorescence Assay DAF-2 Bio-imaging ● Spectrophotometric Assays for RSNOs Saville Assay Modified Saville Assay

21 N-nitrosation of 2,3 diaminonaphthalene (DAN) to yield 2,3-naphthotriazole (NAT) NH 2 NH 2 NH N N H N NH 2 NO N NH 2 N + -H2O-H2O DAN NAT NO + ex = 375nm em = 415nm NO 2 - +H +

22 N-Nitrosation of DAN By Extravasated PMNs Time (hr) Triazole Formation (nM) x10 6 PMNs 2x10 6 PMNs 1x10 6 PMNs Grisham et. al, Gastroenterology, 1992

23 Methods to Quantify NO and its Metabolites in Extracellular Fluids and/or Tissue ● Gas Phase Chemiluminescence (NO) ● Spectrophotometric Assays for Oxidized Metabolites of NO (Nitrite/Nitrate) Griess Assay Fluorescence Assay DAF-2 Bio-imaging ● Spectrophotometric Assays for RSNOs Saville Assay Modified Saville Assay

24 Bioimaging of Nitric Oxide Using Diaminofluoresceine-2 (DAF-2) Assay limitations: Possible interference by reducing agents and divalent cations, requires standardized illumination conditions Advantages: Sensitivity for NO (5 nM in vitro) with high temporal and spatial resolution. No cross-reactivity to NO 2 - /NO 3 - and ONOO - DAF-2 DA non-fluorescent, cell-permeable esterases NO x DAF-2 non-fluorescent DAF-2 T fluorescent, Ex 495 nm, Em 515 nm Kojima et al., Biol.Pharm. Bull. (1997) O NH 2 AcOOAc O O H 2 N O O NH 2 COO - H 2 N - OO H O - O N N N O COO -

25 Propagation of NO Wave during Stimulation of Endothelial Cells with the Calcium Ionophor, A23187 (1 µM) Feelisch et. al. Unpublished Observations t = min 1 min 1.5 min 2 min 5 min

26 The Chemistry of Nitric Oxide Dictates its Physiological Activity Oxidation RNOS Guanylate Cyclase Cytochromes C,O,N Radicals (Lipid Radicals) O2O2 Direct Indirect L-Arginine eNOS nNOS iNOS NO Nitrosation DNA Strand Breaks Lipid Peroxidation Hydroxylation Nitrosothiols Nitrosamines Nitrotyrosine Nitroguanosine Nitration Metal Complexes/Alkyl Radicals

27 Physiological Roles of Nitrosothiols (RSNOs) Potent vasorelaxants. Regulation of cell signaling/ protein functions. Antiplatelet activity. Intermediates in the metabolism of organic nitrites and nitrates. Antimicrobial activity. Regulation of vasodilation/ oxygenation (hemoglobin). RSNOs S-Nitrosoglutathione (GSNO) S-Nitrosoalbumin (AlbSNO) S-Nitrosohemoglobin (HbSNO)

28 NO-Dependent Formation of S-Nitrosothiols (RSNOs): Large Amounts of NO 2 NO + O 2 2 NO 2 2 NO NO 2 N 2 O 3 2 N 2 O RSH 2 RSNO + 2 NO 2 - RSNOs S-Nitrosohemoglobin (SNOHb) S-Nitrosoglutathione (SNOGSH ) S-Nitrosoalbumin (SNOAlb)

29 NO-Dependent Formation of S-Nitrosothiols (RSNOs): Physiological Levels of Oxygen, NO and RSH 2 NO + O 2 2 NO 2 2 NO RSH 2 NO RS + 2H + 2 NO + 2 RS 2 RSNO RSNOs S-Nitrosohemoglobin (SNOHb) S-Nitrosoglutathione (SNOGSH ) S-Nitrosoalbumin (SNOAlb) ● ●

30 Methods to Quantify NO and its Metabolites in Extracellular Fluids and/or Tissue ● Gas Phase Chemiluminescence (NO) ● Spectrophotometric Assays for Oxidized Metabolites of NO (Nitrite/Nitrate) Griess Assay Fluorescence Assay DAF-2 Bio-imaging ● Spectrophotometric Assays for RSNOs Saville Assay Modified Saville Assay

31 Saville Reaction RSNO + Hg +2 RS - + Hg +3 + NO +

32 Saville/Griess Reaction 2 + NO + H 2 NSO 3 NN + + H 2 NSO 3 NH Sulfanilamide NHNH 2 N-(1-Naphthyl)ethylenediamine NHNH 2 NNH 2 NSO 3 Azo Dye ( max = 540 nm) RSNO + Hg +2 + RS -

33 Methods to Quantify NO and its Metabolites in Extracellular Fluids and/or Tissue ● Gas Phase Chemiluminescence (NO) ● Spectrophotometric Assays for Oxidized Metabolites of NO (Nitrite/Nitrate) Griess Assay Fluorescence Assay DAF-2 Bio-imaging ● Spectrophotometric Assays for RSNOs Saville Assay Modified Saville Assay

34 Fluorometric Determination of S-Nitrosothiols (RSNO) NH N NN NH 2 N+N+ NH 2 NH 2 H N NH 2 NO -H 2 O NO + RSNO + Hg +2 DAN NAT

35 S-Nitrosothiol Formation in Blood of LPS-Treated Rats * + * S-Nitrosothiol Concentration (nM) Control + LPS Jourd’heuil et al BBRC, 2000 SNO-Alb SNO-Hb

36 The Chemistry of Nitric Oxide Dictates its Physiological Activity Oxidation RNOS Guanylate Cyclase Cytochromes C,O,N Radicals (Lipid Radicals) O2- O2- Direct Indirect L-Arginine eNOS nNOS iNOS NO Nitrosation DNA Strand Breaks Lipid Peroxidation Hydroxylation Nitrosothiols Nitrosamines Nitrotyrosine Nitroguanosine Nitration Metal Complexes/Alkyl Radicals

37 O NO ONOO - ONOO - + H + ONOOH ONOOH ONOOH * (“OH. + NO 2. ”) ONOOH * NO H + Sum: O NO NO 3 - Interaction Between Superoxide and Nitric Oxide: Formation of Peroxynitrite/Peroxynitrous Acid + H +

38 OH N O 2 R OH R + ONOO - Tyrosine 3-Nitrotyrosine Peroxynitrite Nitrates Tyrosine to Yield 3-Nitrotyrosine

39 3-Nitrotyrosine Formation in vivo: Specific Footprint for Peroxynitrite?

40 Hemoproteins (MPO,Mb) + H 2 O 2 + NO 2 R OH N O 2 Generation of 3-Nitrotyrosine ONOO _ NO 2 HNO O2O2 _ NO 2 + H + NO HOCl + NO 2 _ _ O2O2

41 Myoglobin-Catalyzed Formation of 3-Nitrotyrosine (3-NT) Time (min.) 3-Nitrotyrosine Formation (uM) Kilinc and Grisham BBRC, 2001 H 2 O 2 + NO Tyr 3NT Mb

42 Martin Feelisch (NitroMed) Steve Laroux (Harvard) Kamer Kilinc (Ankara Univ) LSU Health Sciences Center Grambling State University Allen M. Miles National Cancer Institute David A. Wink Mike Espey Katrina Miranda (Univ Arizona) Albany College of Medicine David Jourd’heuil LSU


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