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Published byAbril Boram Modified over 9 years ago
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S-glutathionylated biomarker plasma proteins
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Low pK cysteine residue S-glutathionylation Deglutathionylation Cysteinyl radical Sulfinic acidSulfonic acidSulfenic acid [O] [N] S-Glutathionylation Cycle Protected Glutaredoxin Sulfiredoxin (GSTP) Oxidation Reduction degrade Grx From: Tew, Biochem. Pharmacology 2007
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Protein clusters subject to S-glutathionylation 1.Cytoskeletal (actin) 2.Glycolysis/energy metabolism (e.g. GAPDH, pyruvate kinase, triose phosphoisomerase,phosphoglycerate kinase, aldolase, ketoglutarate dehydrogenase, isocitrate dehydrogenase) 3.Signaling pathways (e.g. MEKK1, Nf B, STAT3, PKC, cAMP dependent PKA, p53, GTPase p21 ras, Trx, GSTP) 4.Calcium homeostasis (e.g. S100A1, SERCA, calmodulin, ryanodine receptor) 5.Phosphatases (e.g. PTP1B, PTEN, PP1, Cdc2, Cdc25a/b) 6.Protein folding (e.g. PDI, HSP65, 20S proteosome) 6.Serine protease inhibitors (SERPIN’s) From: Townsend, Molecular Interventions 2008
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SERPIN’s Serine Protease Inhibitors Inactivate enzymes by binding them covalently Have a characteristic secondary structure of beta sheets and alpha helices antitrypsinantichymotrypsin
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From: Silverman et al, 2006 Possible pathway of activation of proteases by serpinA1 S-glutathionylation Site of S-glutathionylation?
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MALDI-TOF identification of S-glutathionylated plasma proteins following NOV-002 treatment Protein NCBI Accession # Confidence Interval (A) Complement C3 1352102 100% (B, D) Serpin A1 6678087 100% (C) Contrapsin (Serpin A3) 54173 100% A B C D Kda 150 100 75 50 37 NOV-002 (25 mg/kg, iv) 0 ¼ ½ 1 4 24 h WB: PSSG WB: albumin A Mice treated in vivo Mouse plasma treated ex vivo
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D Figure 2 WB:PSSG WB:Serpin A3 0 1 2.5 5 10 20 30 min WB:PSSG WB:Serpin A1 0 1 2.5 5 10 20 30 min A B 0 5 10 25 50 75 100 μM PABA/NO 0 5 10 25 50 75 100 μM PABA/NO WB:PSSG WB: Serpin A1 WB:PSSG WB: Serpin A3 C S-glutathionylation of Serpins A1 & A3 is time and dose dependent and impacts protein structure
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y1* = cysteine + 305 + H 2 O, this ion in absent in the unmodified peptide RLGMFNIQHC*K RLGMFNIQHCK Figure 3A : Serpin A1 is S-glutathionylated at Cys 256 liquid chromatography (LC)-electrospray ionization (ESI)-tandem mass spectrometry (MS/MS)
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DEELSCTVVELK DEELSC*TVVELK y7* = cysteine + 305, this ion in absent in the unmodified peptide Figure 3B : Serpin A3 is S-glutathionylated at Cys 263 liquid chromatography (LC)-electrospray ionization (ESI)-tandem mass spectrometry (MS/MS)
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a c b WB: PSSG WB:albumin 0 2.5 5 15 30 60 120 240 min 75 75 5050 100100 150150 Figure 4 Time Relative Intensity 40μM NOV-002; 20μg plasma A3 IP: WB: SerpinA1 NOV-002: - + - + 250 75 50 100 150 37 A1 - IP: WB: PSSG A3 NOV-002: + - + - + A1 WB: PSSG WB: SerpinA3 A. B. 250 75 50 100 150 37 Immunoprecipitation human plasma treated with 40 mol/L NOV-002 for 1h and biotinylated serpin A1 and A3 antibodies were used to pull-down total unmodified and modified serpins.
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Figure 5 1 2 3 4 5 6 WB: albumin WB: Serpin A1 WB: Serpin A3 WB:PSSGWB:PSSG A. B. C.C. PSSGa IA1) PSSGb(A3) PSSGc(A1) Unmodified serpins are elevated in certain cancers while the ratio of S- glutathionylated to unmodified serpin is decreased
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WB:PSSG WB: albumin 1 2 3 4 1 2 3 4 1 5 6 7 8 1 5 6 7 8 - - - - + + + + - - - - - + + + + + 100μM NOV-002 WB: Serpin A3 WB: Serpin A1 A. PSSGa IA1) PSSGb(A3) PSSGc(A1) Ex vivo treatment with NOV-002 induces serpin A1 and A3 S-glutathionylation and results in greater relative increases in Serpin A1 glutathionylation in normal human plasma
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Parametric data were analyzed using T-tests and non-parametric data using Wilcoxon matched-pairs signed rank test. Data are mean for 45 cancer samples and 8 disease- free +/- SEM. B. C. WB: SERPIN A1 52kDa WB: SERPIN A3 66kDa WB: Albumin 0 2.5 5 15 30 60 120 240 min D. E.
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Low pK cysteine residue S-glutathionylation Deglutathionylation Cysteinyl radical Sulfinic acidSulfonic acidSulfenic acid [O] [N] S-Glutathionylation Cycle Protected Glutaredoxin Sulfiredoxin (GSTP) Oxidation Reduction degrade Grx From: Tew, Biochem. Pharmacology 2007
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1 2 3 4 WB:GSTp WB: albumin WB: Grx1 Figure 7 Cancer patient plasma have decreased GSTP and elevated Grx1.
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What next? Insert biomarkers into a protocol where treatments are likely to modulate redox homeostasis. Volunteers?
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