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Sean S. Davies - One of the best experts on this subject based on the ideXlab platform.
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modification by isolevuglandins highly reactive γ Ketoaldehydes deleteriously alters high density lipoprotein structure and function
Journal of Biological Chemistry, 2018Co-Authors: Linda S Mayzhang, Jiansheng Huang, Patricia G Yancey, Macrae F Linton, Valery Yermalitsky, Tiffany Pleasent, Mark S Borja, Michael N Oda, Gray W Jerome, Sean S. DaviesAbstract:Cardiovascular disease risk depends on high-density lipoprotein (HDL) function, not HDL-cholesterol. Isolevuglandins (IsoLGs) are lipid dicarbonyls that react with lysine residues of proteins and phosphatidylethanolamine. IsoLG adducts are elevated in atherosclerosis. The consequences of IsoLG modification of HDL have not been studied. We hypothesized that IsoLG modification of apoA-I deleteriously alters HDL function. We determined the effect of IsoLG on HDL structure-function and whether pentylpyridoxamine (PPM), a dicarbonyl scavenger, can preserve HDL function. IsoLG adducts in HDL derived from patients with familial hypercholesterolemia (n = 10, 233.4 ± 158.3 ng/mg) were found to be significantly higher than in healthy controls (n = 7, 90.1 ± 33.4 pg/mg protein). Further, HDL exposed to myeloperoxidase had elevated IsoLG-lysine adducts (5.7 ng/mg protein) compared with unexposed HDL (0.5 ng/mg protein). Preincubation with PPM reduced IsoLG-lysine adducts by 67%, whereas its inactive analogue pentylpyridoxine did not. The addition of IsoLG produced apoA-I and apoA-II cross-links beginning at 0.3 molar eq of IsoLG/mol of apoA-I (0.3 eq), whereas succinylaldehyde and 4-hydroxynonenal required 10 and 30 eq. IsoLG increased HDL size, generating a subpopulation of 16-23 nm. 1 eq of IsoLG decreased HDL-mediated [3H]cholesterol efflux from macrophages via ABCA1, which corresponded to a decrease in HDL-apoA-I exchange from 47.4% to only 24.8%. This suggests that IsoLG inhibits apoA-I from disassociating from HDL to interact with ABCA1. The addition of 0.3 eq of IsoLG ablated HDL's ability to inhibit LPS-stimulated cytokine expression by macrophages and increased IL-1β expression by 3.5-fold. The structural-functional effects were partially rescued with PPM scavenging.
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abstract 576 salicylamine a γ Ketoaldehyde scavenger improves hdl function and reduces atherosclerosis in apoe deficient mice
Arteriosclerosis Thrombosis and Vascular Biology, 2017Co-Authors: Jiansheng Huang, John A. Oates, Sean S. Davies, Venkataraman Amarnath, Patricia G Yancey, Lei Ding, Youmin Zhang, Jackson Roberts, Macrae F LintonAbstract:Background: Lipid peroxidation products impair the cholesterol efflux capacity of high-density lipoprotein (HDL) and promote the development of atherosclerosis. The impact of inhibition of malondialdehyde (MDA)-HDL adduct formation by scavengers on HDL function and whether small molecule aldehyde scavengers protect against the development of atherosclerosis was examined. Methods and Results: Western blot analysis of ApoAI revealed that the amount of ApoAI crosslinking increased with MDA concentration. In the presence of LPS, MDA-HDL (HDL modified by 1mM MDA) versus control HDL stimulated 2- and 1.8-fold more expression of TNF-α and IL-1β in Apoe-/- macrophages demonstrating that MDA-HDL has reduced anti-inflammatory function. HDL-mediated macrophage cholesterol efflux was decreased by ~ 42%, 55%, 70%, and 80%, respectively, for HDL modified with 0.125 mM, 0.25 mM, 0.5 mM, and 1mM MDA, demonstrating that MDA modification of HDL affects its cholesterol efflux capacity in a dose dependent manner. Analysis by Western blot demonstrated that 5mM of salicylamine (SAM) and 5mM of pentylpyridoxamine (PPM), γ-Ketoaldehyde scavengers, attenuated MDA mediated crosslinking of apoA-I in HDL (molar ratio of MDA and HDL is 1:5) by 60% and 80 % (P Apoe-/- macrophages. In addition, pretreatment of LDL with SAM prevented MDA-ApoB adduct formation, and compared to incubation with LDL containing MDA-ApoB adducts, SAM treatment resulted in 57% less cholesterol accumulation in J774 macrophages. Importantly, administration of the Ketoaldehyde scavenger, SAM, versus the nonreactive analogue, 4-SAM, to Apoe-/- mice consuming a Western diet for 16 weeks reduced the extent of proximal aortic atherosclerosis by 28% (P Conclusions: Treatment with salicylamine, a γ-Ketoaldehyde scavenger: 1) inhibits MDA-ApoA1 adduct formation thereby preserving HDL cholesterol efflux capacity; 2) prevents MDA-apoB100 formation resulting in less macrophage cholesterol accumulation; 3) reduces atherosclerosis in Apoe -/- mice. These results support the therapeutic potential of salicylamine in the treatment of atherosclerotic cardiovascular disease.
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phosphatidylethanolamines modified by γ Ketoaldehyde γka induce endoplasmic reticulum stress and endothelial activation
Journal of Biological Chemistry, 2011Co-Authors: Lilu Guo, Venkataraman Amarnath, Zhongyi Chen, Brian E Cox, Raquel F Epand, Richard M Epand, Sean S. DaviesAbstract:Peroxidation of plasma lipoproteins has been implicated in the endothelial cell activation and monocyte adhesion that initiate atherosclerosis, but the exact mechanisms underlying this activation remain unclear. Lipid peroxidation generates lipid aldehydes, including the γ-Ketoaldehydes (γKA), also termed isoketals or isolevuglandins, that readily modify the amine headgroup of phosphatidylethanolamine (PE). We hypothesized that aldehyde modification of PE could mediate some of the proinflammatory effects of lipid peroxidation. We found that PE modified by γKA (γKA-PE) induced THP-1 monocyte adhesion to human umbilical cord endothelial cells. γKA-PE also induced expression of adhesion molecules and increased MCP-1 and IL-8 mRNA in human umbilical cord endothelial cells. To determine the structural requirements for γKA-PE activity, we tested several related compounds. PE modified by 4-oxo-pentanal induced THP-1 adhesion, but N-glutaroyl-PE and C18:0N-acyl-PE did not, suggesting that an N-pyrrole moiety was essential for cellular activity. As the N-pyrrole headgroup might distort the membrane, we tested the effect of the pyrrole-PEs on membrane parameters. γKA-PE and 4-oxo-pentanal significantly reduced the temperature for the liquid crystalline to hexagonal phase transition in artificial bilayers, suggesting that these pyrrole-PE markedly altered membrane curvature. Additionally, fluorescently labeled γKA-PE rapidly internalized to the endoplasmic reticulum (ER); γKA-PE induced C/EBP homologous protein CHOP and BiP expression and p38 MAPK activity, and inhibitors of ER stress reduced γKA-PE-induced C/EBP homologous protein CHOP and BiP expression as well as EC activation, consistent with γKA-PE inducing ER stress responses that have been previously linked to inflammatory chemokine expression. Thus, γKA-PE is a potential mediator of the inflammation induced by lipid peroxidation.
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treatment with a γ Ketoaldehyde scavenger prevents working memory deficits in hapoe4 mice
Journal of Alzheimer's Disease, 2011Co-Authors: Sean S. Davies, Thomas J. Montine, Venkataraman Amarnath, Nathalie Bernoudhubac, Elena Matafonova, Chris Bodine, Brooke G Pantazides, Fiona E Harrison, Sandra J Olson, Jackson L RobertsAbstract:Both inflammation and oxidative injury are features of Alzheimer’s disease (AD), but the contribution of these intertwined phenomena to the loss of working memory in this disease is unclear. We tested the hypothesis that highly reactive γ-Ketoaldehydes that are formed both by non-enzymatic free radical catalyzed lipid peroxidation and by cyclooxygenases may be causally linked to the development of memory impairment in AD. We found that levels of γ-Ketoaldehyde protein adducts were increased in the hippocampus of brains obtained postmortem from patients with AD compared to age-matched controls, but that levels of γ-Ketoaldehyde protein adducts in the cerebellum were not different in the two groups. Moreover, immunohistochemistry revealed that adducts localized to hippocampal pyramidal neurons. We tested the effect of an orally available γ-Ketoaldehyde scavenger, salicylamine, on the development of spatial working memory deficits in hApoE4 targeted replacement mice, a mouse model of dementia. Long-term salicylamine supplementation did not significantly alter body weight or survival, but protected against the development of age-related deficits in spatial working memory in 12–14 month old ApoE4 mice. These findings suggest that γ-Ketoaldehyde adduct formation is associated with damage to hippocampal neurons in patients with AD and can contribute to the pathogenesis of spatial working memory deficits in hApoE4 mice. These data provide a rational basis for future studies exploring whether γ-Ketoaldehyde scavengers may mitigate the development of cognitive dysfunction in patients with AD
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phosphatidylethanolamines modified by Ketoaldehyde ka induce endoplasmic reticulum stress and endothelial
2011Co-Authors: Lilu Guo, Venkataraman Amarnath, Zhongyi Chen, Brian E Cox, Raquel F Epand, Richard M Epand, Sean S. DaviesAbstract:Peroxidation of plasma lipoproteins has been implicated in the endothelial cell activation and monocyte adhesion that initiate atherosclerosis, but the exact mechanisms underlying this activation remain unclear. Lipid peroxidation generates lipid aldehydes, including the -Ketoaldehydes (KA), also termed isoketals or isolevuglandins, that readily modify the amine headgroup of phosphatidylethanolamine (PE). We hypothesized that aldehyde modification of PE could mediate some of the proinflammatory effects of lipid peroxidation. We found that PE modified by KA (KA-PE) induced THP-1 monocyte adhesion to human umbilical cord endothelial cells. KA-PE also induced expression of adhesion molecules and increased MCP-1 and IL-8 mRNA in human umbilical cord endothelial cells. To determine the structural requirements for KA-PE activity, we tested several related compounds. PE modified by 4-oxo-pentanal induced THP-1 adhesion, but N-glutaroyl-PE and C18:0N-acyl-PE did not, suggesting that an N-pyrrole moiety was essential for cellular activity. As the N-pyrrole headgroup might distort the membrane, we tested the effect of the pyrrolePEs on membrane parameters.KA-PE and 4-oxo-pentanal significantly reduced the temperature for the liquid crystalline to hexagonal phase transition in artificial bilayers, suggesting that these pyrrole-PE markedly altered membrane curvature. Additionally, fluorescently labeled KA-PE rapidly internalized to the endoplasmic reticulum (ER); KA-PE induced C/EBP homologous protein CHOP and BiP expression and p38 MAPK activity, and inhibitors of ER stress reduced KA-PE-induced C/EBP homologous protein CHOP and BiP expression as well as EC activation, consistent with KA-PE inducing ER stress responses that have been previously linked to inflammatory chemokine expression. Thus,KA-PE is a potential mediator of the inflammation induced by lipid peroxidation.
Venkataraman Amarnath - One of the best experts on this subject based on the ideXlab platform.
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abstract 576 salicylamine a γ Ketoaldehyde scavenger improves hdl function and reduces atherosclerosis in apoe deficient mice
Arteriosclerosis Thrombosis and Vascular Biology, 2017Co-Authors: Jiansheng Huang, John A. Oates, Sean S. Davies, Venkataraman Amarnath, Patricia G Yancey, Lei Ding, Youmin Zhang, Jackson Roberts, Macrae F LintonAbstract:Background: Lipid peroxidation products impair the cholesterol efflux capacity of high-density lipoprotein (HDL) and promote the development of atherosclerosis. The impact of inhibition of malondialdehyde (MDA)-HDL adduct formation by scavengers on HDL function and whether small molecule aldehyde scavengers protect against the development of atherosclerosis was examined. Methods and Results: Western blot analysis of ApoAI revealed that the amount of ApoAI crosslinking increased with MDA concentration. In the presence of LPS, MDA-HDL (HDL modified by 1mM MDA) versus control HDL stimulated 2- and 1.8-fold more expression of TNF-α and IL-1β in Apoe-/- macrophages demonstrating that MDA-HDL has reduced anti-inflammatory function. HDL-mediated macrophage cholesterol efflux was decreased by ~ 42%, 55%, 70%, and 80%, respectively, for HDL modified with 0.125 mM, 0.25 mM, 0.5 mM, and 1mM MDA, demonstrating that MDA modification of HDL affects its cholesterol efflux capacity in a dose dependent manner. Analysis by Western blot demonstrated that 5mM of salicylamine (SAM) and 5mM of pentylpyridoxamine (PPM), γ-Ketoaldehyde scavengers, attenuated MDA mediated crosslinking of apoA-I in HDL (molar ratio of MDA and HDL is 1:5) by 60% and 80 % (P Apoe-/- macrophages. In addition, pretreatment of LDL with SAM prevented MDA-ApoB adduct formation, and compared to incubation with LDL containing MDA-ApoB adducts, SAM treatment resulted in 57% less cholesterol accumulation in J774 macrophages. Importantly, administration of the Ketoaldehyde scavenger, SAM, versus the nonreactive analogue, 4-SAM, to Apoe-/- mice consuming a Western diet for 16 weeks reduced the extent of proximal aortic atherosclerosis by 28% (P Conclusions: Treatment with salicylamine, a γ-Ketoaldehyde scavenger: 1) inhibits MDA-ApoA1 adduct formation thereby preserving HDL cholesterol efflux capacity; 2) prevents MDA-apoB100 formation resulting in less macrophage cholesterol accumulation; 3) reduces atherosclerosis in Apoe -/- mice. These results support the therapeutic potential of salicylamine in the treatment of atherosclerotic cardiovascular disease.
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levuglandin forms adducts with histone h4 in a cyclooxygenase 2 dependent manner altering its interaction with dna
Biochemistry, 2014Co-Authors: Erica J Carrier, Olivier Boutaud, Irene Zagolikapitte, Venkataraman Amarnath, John A. OatesAbstract:Inflammation and subsequent cyclooxygenase-2 (COX-2) activity has long been linked with the development of cancer, although little is known about any epigenetic effects of COX-2. A product of COX-2 activation, levuglandin (LG) quickly forms covalent bonds with nearby primary amines, such as those in lysine, which leads to LG-protein adducts. Here, we demonstrate that COX-2 activity causes LG-histone adducts in cultured cells and liver tissue, detectable through LC–MS, with the highest incidence in histone H4. Adduction is blocked by a γ-Ketoaldehyde scavenger, which has no effect on COX-2 activity as measured by PGE2 production. Formation of the LG-histone adduct is associated with an increased histone solubility in NaCl, indicating destabilization of the nucleosome structure; this is also reversed with scavenger treatment. These data demonstrate that COX-2 activity can cause histone adduction and loosening of the nucleosome complex, which could lead to altered transcription and contribute to carcinogenesis.
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phosphatidylethanolamines modified by γ Ketoaldehyde γka induce endoplasmic reticulum stress and endothelial activation
Journal of Biological Chemistry, 2011Co-Authors: Lilu Guo, Venkataraman Amarnath, Zhongyi Chen, Brian E Cox, Raquel F Epand, Richard M Epand, Sean S. DaviesAbstract:Peroxidation of plasma lipoproteins has been implicated in the endothelial cell activation and monocyte adhesion that initiate atherosclerosis, but the exact mechanisms underlying this activation remain unclear. Lipid peroxidation generates lipid aldehydes, including the γ-Ketoaldehydes (γKA), also termed isoketals or isolevuglandins, that readily modify the amine headgroup of phosphatidylethanolamine (PE). We hypothesized that aldehyde modification of PE could mediate some of the proinflammatory effects of lipid peroxidation. We found that PE modified by γKA (γKA-PE) induced THP-1 monocyte adhesion to human umbilical cord endothelial cells. γKA-PE also induced expression of adhesion molecules and increased MCP-1 and IL-8 mRNA in human umbilical cord endothelial cells. To determine the structural requirements for γKA-PE activity, we tested several related compounds. PE modified by 4-oxo-pentanal induced THP-1 adhesion, but N-glutaroyl-PE and C18:0N-acyl-PE did not, suggesting that an N-pyrrole moiety was essential for cellular activity. As the N-pyrrole headgroup might distort the membrane, we tested the effect of the pyrrole-PEs on membrane parameters. γKA-PE and 4-oxo-pentanal significantly reduced the temperature for the liquid crystalline to hexagonal phase transition in artificial bilayers, suggesting that these pyrrole-PE markedly altered membrane curvature. Additionally, fluorescently labeled γKA-PE rapidly internalized to the endoplasmic reticulum (ER); γKA-PE induced C/EBP homologous protein CHOP and BiP expression and p38 MAPK activity, and inhibitors of ER stress reduced γKA-PE-induced C/EBP homologous protein CHOP and BiP expression as well as EC activation, consistent with γKA-PE inducing ER stress responses that have been previously linked to inflammatory chemokine expression. Thus, γKA-PE is a potential mediator of the inflammation induced by lipid peroxidation.
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treatment with a γ Ketoaldehyde scavenger prevents working memory deficits in hapoe4 mice
Journal of Alzheimer's Disease, 2011Co-Authors: Sean S. Davies, Thomas J. Montine, Venkataraman Amarnath, Nathalie Bernoudhubac, Elena Matafonova, Chris Bodine, Brooke G Pantazides, Fiona E Harrison, Sandra J Olson, Jackson L RobertsAbstract:Both inflammation and oxidative injury are features of Alzheimer’s disease (AD), but the contribution of these intertwined phenomena to the loss of working memory in this disease is unclear. We tested the hypothesis that highly reactive γ-Ketoaldehydes that are formed both by non-enzymatic free radical catalyzed lipid peroxidation and by cyclooxygenases may be causally linked to the development of memory impairment in AD. We found that levels of γ-Ketoaldehyde protein adducts were increased in the hippocampus of brains obtained postmortem from patients with AD compared to age-matched controls, but that levels of γ-Ketoaldehyde protein adducts in the cerebellum were not different in the two groups. Moreover, immunohistochemistry revealed that adducts localized to hippocampal pyramidal neurons. We tested the effect of an orally available γ-Ketoaldehyde scavenger, salicylamine, on the development of spatial working memory deficits in hApoE4 targeted replacement mice, a mouse model of dementia. Long-term salicylamine supplementation did not significantly alter body weight or survival, but protected against the development of age-related deficits in spatial working memory in 12–14 month old ApoE4 mice. These findings suggest that γ-Ketoaldehyde adduct formation is associated with damage to hippocampal neurons in patients with AD and can contribute to the pathogenesis of spatial working memory deficits in hApoE4 mice. These data provide a rational basis for future studies exploring whether γ-Ketoaldehyde scavengers may mitigate the development of cognitive dysfunction in patients with AD
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phosphatidylethanolamines modified by Ketoaldehyde ka induce endoplasmic reticulum stress and endothelial
2011Co-Authors: Lilu Guo, Venkataraman Amarnath, Zhongyi Chen, Brian E Cox, Raquel F Epand, Richard M Epand, Sean S. DaviesAbstract:Peroxidation of plasma lipoproteins has been implicated in the endothelial cell activation and monocyte adhesion that initiate atherosclerosis, but the exact mechanisms underlying this activation remain unclear. Lipid peroxidation generates lipid aldehydes, including the -Ketoaldehydes (KA), also termed isoketals or isolevuglandins, that readily modify the amine headgroup of phosphatidylethanolamine (PE). We hypothesized that aldehyde modification of PE could mediate some of the proinflammatory effects of lipid peroxidation. We found that PE modified by KA (KA-PE) induced THP-1 monocyte adhesion to human umbilical cord endothelial cells. KA-PE also induced expression of adhesion molecules and increased MCP-1 and IL-8 mRNA in human umbilical cord endothelial cells. To determine the structural requirements for KA-PE activity, we tested several related compounds. PE modified by 4-oxo-pentanal induced THP-1 adhesion, but N-glutaroyl-PE and C18:0N-acyl-PE did not, suggesting that an N-pyrrole moiety was essential for cellular activity. As the N-pyrrole headgroup might distort the membrane, we tested the effect of the pyrrolePEs on membrane parameters.KA-PE and 4-oxo-pentanal significantly reduced the temperature for the liquid crystalline to hexagonal phase transition in artificial bilayers, suggesting that these pyrrole-PE markedly altered membrane curvature. Additionally, fluorescently labeled KA-PE rapidly internalized to the endoplasmic reticulum (ER); KA-PE induced C/EBP homologous protein CHOP and BiP expression and p38 MAPK activity, and inhibitors of ER stress reduced KA-PE-induced C/EBP homologous protein CHOP and BiP expression as well as EC activation, consistent with KA-PE inducing ER stress responses that have been previously linked to inflammatory chemokine expression. Thus,KA-PE is a potential mediator of the inflammation induced by lipid peroxidation.
Michael Legge - One of the best experts on this subject based on the ideXlab platform.
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oocyte and zygote Ketoaldehyde utilisation
Biochimica et Biophysica Acta, 1997Co-Authors: Michael LeggeAbstract:Abstract Mouse oocytes and zygotes, when solubilised demonstrated that a range of Ketoaldehydes could be utilised as substrates. Of the five Ketoaldehydes investigated the overall substrate utilisation was hydroxypyruvate>glyoxylate>2-ketobutyrate>pyruvate>glycolate. The utilisation of these Ketoaldehydes during early development by LD-1 may provide a source of new metabolic substrates in addition to the potential control of aldehyde toxicity. It is proposed therefore that the LD-1 isoenzyme is responsible for Ketoaldehyde utilisation prior to implantation thereby providing a source of alternative metabolic substrates for the developing embryo.
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rapid report oocyte and zygote Ketoaldehyde utilisation
1997Co-Authors: Michael LeggeAbstract:Mouse oocytes and zygotes, when solubilised demonstrated that a range of Ketoaldehydes could be utilised as substrates. Of the five Ketoaldehydes investigated the overall substrate utilisation was hydroxypyruvate ) glyoxylate ) 2-ketobutyrate ) pyruvate) glycolate. The utilisation of these Ketoaldehydes during early development by LD-1 may provide a source of new metabolic substrates in addition to the potential control of aldehyde toxicity. It is proposed therefore that the LD-1 isoenzyme is responsible for Ketoaldehyde utilisation prior to implantation thereby providing a source of alternative metabolic substrates for the developing embryo.
Jackson L Roberts - One of the best experts on this subject based on the ideXlab platform.
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treatment with a γ Ketoaldehyde scavenger prevents working memory deficits in hapoe4 mice
Journal of Alzheimer's Disease, 2011Co-Authors: Sean S. Davies, Thomas J. Montine, Venkataraman Amarnath, Nathalie Bernoudhubac, Elena Matafonova, Chris Bodine, Brooke G Pantazides, Fiona E Harrison, Sandra J Olson, Jackson L RobertsAbstract:Both inflammation and oxidative injury are features of Alzheimer’s disease (AD), but the contribution of these intertwined phenomena to the loss of working memory in this disease is unclear. We tested the hypothesis that highly reactive γ-Ketoaldehydes that are formed both by non-enzymatic free radical catalyzed lipid peroxidation and by cyclooxygenases may be causally linked to the development of memory impairment in AD. We found that levels of γ-Ketoaldehyde protein adducts were increased in the hippocampus of brains obtained postmortem from patients with AD compared to age-matched controls, but that levels of γ-Ketoaldehyde protein adducts in the cerebellum were not different in the two groups. Moreover, immunohistochemistry revealed that adducts localized to hippocampal pyramidal neurons. We tested the effect of an orally available γ-Ketoaldehyde scavenger, salicylamine, on the development of spatial working memory deficits in hApoE4 targeted replacement mice, a mouse model of dementia. Long-term salicylamine supplementation did not significantly alter body weight or survival, but protected against the development of age-related deficits in spatial working memory in 12–14 month old ApoE4 mice. These findings suggest that γ-Ketoaldehyde adduct formation is associated with damage to hippocampal neurons in patients with AD and can contribute to the pathogenesis of spatial working memory deficits in hApoE4 mice. These data provide a rational basis for future studies exploring whether γ-Ketoaldehyde scavengers may mitigate the development of cognitive dysfunction in patients with AD
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reactive γ Ketoaldehydes formed via the isoprostane pathway disrupt mitochondrial respiration and calcium homeostasis
Free Radical Biology and Medicine, 2010Co-Authors: Irina G Stavrovskaya, Sean S. Davies, Jackson L Roberts, Sergei V Baranov, Xiaofeng Guo, Bruce S KristalAbstract:Isoketals (IsoKs) are gamma-Ketoaldehydes formed via the isoprostane pathway of arachidonic acid peroxidation and are among the most reactive by-products of lipid peroxidation. IsoKs selectively adduct to protein lysine residues and are highly cytotoxic, but the targets and molecular events involved in IsoK-induced cell death are poorly defined. Our previous work established that physiologically relevant aldehydes induce mitochondrial dysfunction (Kristal et al., J. Biol. Chem.271:6033-6038; 1996). We therefore examined whether IsoKs induced mitochondrial dysfunction. Incubation of mitochondria with synthetic IsoKs in the presence or absence of Ca(2+) was associated with alterations in mitochondrial respiration, membrane potential (DeltaPsi), and pyridine nucleotide redox state. IsoKs dose dependently (0.5-4microM) accelerated liver mitochondria swelling induced by low concentrations of Ca(2+) and Zn(2+) or by the prooxidant tert-butylhydroperoxide, and release of cytochrome c, with similar observations in heart/brain mitochondria. The mitochondrial permeability transition (mPT) inhibitor cyclosporine A delayed IsoK-induced mitochondria dysfunction. The actions of IsoKs are consistent with interactions with cytochrome c, a protein rich in lysine residues. Direct reaction of IsoKs with select lysines in cytochrome c was demonstrated using high-resolution mass spectrometry. Overall, these results suggest that IsoKs may, in part, mediate their cytotoxic effects through induction of the mPT and subsequent activation of downstream cell death cascades.
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determination of the pharmacokinetics and oral bioavailability of salicylamine a potent γ Ketoaldehyde scavenger by lc ms ms
Pharmaceutics, 2010Co-Authors: Irene Zagolikapitte, Olivier Boutaud, John A. Oates, Venkataraman Amarnath, Jackson L Roberts, Elena Matafonova, Christopher L Bodine, Rommel G Tirona, Sean S. DaviesAbstract:Levels of reactive γ-Ketoaldehydes derived from arachidonate increase in diseases associated with inflammation and oxidative injury. To assess the biological importance of these γ-Ketoaldehydes, we previously identified salicylamine as an effective γ-Ketoaldehyde scavenger in vitro and in cells. To determine if salicylamine could be administered in vivo, we developed an LC/MS/MS assay to measure salicylamine in plasma and tissues. In mice, half-life (t1/2) was 62 minutes. Drinking water supplementation (1-10 g/L) generated tissue concentrations (10-500 μM) within the range previously shown to inhibit γ-Ketoaldehydes in cells. Therefore, oral administration of salicylamine can be used to assess the contribution of γ-Ketoaldehydes in animal models of disease.
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measurement of chronic oxidative and inflammatory stress by quantification of isoketal levuglandin gamma Ketoaldehyde protein adducts using liquid chromatography tandem mass spectrometry
Nature Protocols, 2007Co-Authors: Sean S. Davies, Olivier Boutaud, Venkataraman Amarnath, Cynthia J Brame, Jackson L RobertsAbstract:Measurement of F2-isoprostanes (F2-IsoPs) has been independently verified as one of the most reliable approaches to assess oxidative stress in vivo. However, the rapid clearance of F2-IsoPs makes the timing of sample collection critical for short-lived oxidative insults. Isoketals (IsoKs) are γ-Ketoaldehydes formed via the IsoP pathway of lipid peroxidation that rapidly react with lysyl residues of proteins to form stable protein adducts. Oxidative stress can also activate cyclooxygenases to produce prostaglandin H2, which can form two specific isomers of IsoK—levuglandin (LG) D2 and E2. Because adducted proteins are not rapidly cleared, IsoK/LG protein adduct levels can serve as a dosimeter of oxidative and inflammatory damage over prolonged periods of time as well as brief episodes of injury. Quantification of IsoK/LG protein adducts begins with liquid-phase extraction to separate proteins from lipid membranes, allowing measurement of both IsoK/LG protein adducts and F2-IsoP from the same sample if desired. IsoK/LG-lysyl-lactam adducts are measured by liquid chromatography tandem mass spectrometry after proteolytic digestion of extracted proteins, solid-phase extraction and preparative HPLC.
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pyridoxamine analogues scavenge lipid derived γ Ketoaldehydes and protect against h2o2 mediated cytotoxicity
Biochemistry, 2006Co-Authors: Sean S. Davies, Olivier Boutaud, John A. Oates, Irene Zagolikapitte, Venkataraman Amarnath, Eric J Brantley, Paul A Voziyan, Billy G Hudson, Jackson L RobertsAbstract:Isoketals and levuglandins are highly reactive γ-Ketoaldehydes formed by oxygenation of arachidonic acid in settings of oxidative injury and cyclooxygenase activation, respectively. These compounds rapidly adduct to proteins via lysyl residues, which can alter protein structure/function. We examined whether pyridoxamine, which has been shown to scavenge α-Ketoaldehydes formed by carbohydrate or lipid peroxidation, could also effectively protect proteins from the more reactive γ-Ketoaldehydes. Pyridoxamine prevented adduction of ovalbumin and also prevented inhibition of RNase A and glutathione reductase activity by the synthetic γ-Ketoaldehyde, 15-E2-isoketal. We identified the major products of the reaction of pyridoxamine with the 15-E2-isoketal, including a stable lactam adduct. Two lipophilic analogs of pyridoxamine, salicylamine and 5’O-pentylpyridoxamine, also formed lactam adducts when reacted with 15-E2-isoketal. When we oxidized arachidonic acid in the presence of pyridoxamine or its analogs, pyridoxamine-isoketal adducts were found in significantly greater abundance than the pyridoxamine-N-acyl adducts formed by α-Ketoaldehyde scavenging. Therefore, pyridoxamine and its analogs appear to preferentially scavenge γ-Ketoaldehydes. Both pyridoxamine and its lipophilic analogs inhibited the formation of lysyl-levuglandin adducts in platelets activated ex vivo with arachidonic acid. The two lipophilic pyridoxamine analogs provided significant protection against H2O2-mediated cytotoxicity in HepG2 cells. These results demonstrate the utility of pyridoxamine and lipophilic pyridoxamine analogs to assess the potential contributions of isoketals and levuglandins in oxidant injury and inflammation and suggest their potential utility as pharmaceutical agents in these conditions.
Olivier Boutaud - One of the best experts on this subject based on the ideXlab platform.
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levuglandin forms adducts with histone h4 in a cyclooxygenase 2 dependent manner altering its interaction with dna
Biochemistry, 2014Co-Authors: Erica J Carrier, Olivier Boutaud, Irene Zagolikapitte, Venkataraman Amarnath, John A. OatesAbstract:Inflammation and subsequent cyclooxygenase-2 (COX-2) activity has long been linked with the development of cancer, although little is known about any epigenetic effects of COX-2. A product of COX-2 activation, levuglandin (LG) quickly forms covalent bonds with nearby primary amines, such as those in lysine, which leads to LG-protein adducts. Here, we demonstrate that COX-2 activity causes LG-histone adducts in cultured cells and liver tissue, detectable through LC–MS, with the highest incidence in histone H4. Adduction is blocked by a γ-Ketoaldehyde scavenger, which has no effect on COX-2 activity as measured by PGE2 production. Formation of the LG-histone adduct is associated with an increased histone solubility in NaCl, indicating destabilization of the nucleosome structure; this is also reversed with scavenger treatment. These data demonstrate that COX-2 activity can cause histone adduction and loosening of the nucleosome complex, which could lead to altered transcription and contribute to carcinogenesis.
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determination of the pharmacokinetics and oral bioavailability of salicylamine a potent γ Ketoaldehyde scavenger by lc ms ms
Pharmaceutics, 2010Co-Authors: Irene Zagolikapitte, Olivier Boutaud, John A. Oates, Venkataraman Amarnath, Jackson L Roberts, Elena Matafonova, Christopher L Bodine, Rommel G Tirona, Sean S. DaviesAbstract:Levels of reactive γ-Ketoaldehydes derived from arachidonate increase in diseases associated with inflammation and oxidative injury. To assess the biological importance of these γ-Ketoaldehydes, we previously identified salicylamine as an effective γ-Ketoaldehyde scavenger in vitro and in cells. To determine if salicylamine could be administered in vivo, we developed an LC/MS/MS assay to measure salicylamine in plasma and tissues. In mice, half-life (t1/2) was 62 minutes. Drinking water supplementation (1-10 g/L) generated tissue concentrations (10-500 μM) within the range previously shown to inhibit γ-Ketoaldehydes in cells. Therefore, oral administration of salicylamine can be used to assess the contribution of γ-Ketoaldehydes in animal models of disease.
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measurement of chronic oxidative and inflammatory stress by quantification of isoketal levuglandin gamma Ketoaldehyde protein adducts using liquid chromatography tandem mass spectrometry
Nature Protocols, 2007Co-Authors: Sean S. Davies, Olivier Boutaud, Venkataraman Amarnath, Cynthia J Brame, Jackson L RobertsAbstract:Measurement of F2-isoprostanes (F2-IsoPs) has been independently verified as one of the most reliable approaches to assess oxidative stress in vivo. However, the rapid clearance of F2-IsoPs makes the timing of sample collection critical for short-lived oxidative insults. Isoketals (IsoKs) are γ-Ketoaldehydes formed via the IsoP pathway of lipid peroxidation that rapidly react with lysyl residues of proteins to form stable protein adducts. Oxidative stress can also activate cyclooxygenases to produce prostaglandin H2, which can form two specific isomers of IsoK—levuglandin (LG) D2 and E2. Because adducted proteins are not rapidly cleared, IsoK/LG protein adduct levels can serve as a dosimeter of oxidative and inflammatory damage over prolonged periods of time as well as brief episodes of injury. Quantification of IsoK/LG protein adducts begins with liquid-phase extraction to separate proteins from lipid membranes, allowing measurement of both IsoK/LG protein adducts and F2-IsoP from the same sample if desired. IsoK/LG-lysyl-lactam adducts are measured by liquid chromatography tandem mass spectrometry after proteolytic digestion of extracted proteins, solid-phase extraction and preparative HPLC.
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pyridoxamine analogues scavenge lipid derived γ Ketoaldehydes and protect against h2o2 mediated cytotoxicity
Biochemistry, 2006Co-Authors: Sean S. Davies, Olivier Boutaud, John A. Oates, Irene Zagolikapitte, Venkataraman Amarnath, Eric J Brantley, Paul A Voziyan, Billy G Hudson, Jackson L RobertsAbstract:Isoketals and levuglandins are highly reactive γ-Ketoaldehydes formed by oxygenation of arachidonic acid in settings of oxidative injury and cyclooxygenase activation, respectively. These compounds rapidly adduct to proteins via lysyl residues, which can alter protein structure/function. We examined whether pyridoxamine, which has been shown to scavenge α-Ketoaldehydes formed by carbohydrate or lipid peroxidation, could also effectively protect proteins from the more reactive γ-Ketoaldehydes. Pyridoxamine prevented adduction of ovalbumin and also prevented inhibition of RNase A and glutathione reductase activity by the synthetic γ-Ketoaldehyde, 15-E2-isoketal. We identified the major products of the reaction of pyridoxamine with the 15-E2-isoketal, including a stable lactam adduct. Two lipophilic analogs of pyridoxamine, salicylamine and 5’O-pentylpyridoxamine, also formed lactam adducts when reacted with 15-E2-isoketal. When we oxidized arachidonic acid in the presence of pyridoxamine or its analogs, pyridoxamine-isoketal adducts were found in significantly greater abundance than the pyridoxamine-N-acyl adducts formed by α-Ketoaldehyde scavenging. Therefore, pyridoxamine and its analogs appear to preferentially scavenge γ-Ketoaldehydes. Both pyridoxamine and its lipophilic analogs inhibited the formation of lysyl-levuglandin adducts in platelets activated ex vivo with arachidonic acid. The two lipophilic pyridoxamine analogs provided significant protection against H2O2-mediated cytotoxicity in HepG2 cells. These results demonstrate the utility of pyridoxamine and lipophilic pyridoxamine analogs to assess the potential contributions of isoketals and levuglandins in oxidant injury and inflammation and suggest their potential utility as pharmaceutical agents in these conditions.
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prostaglandin h2 derived adducts of proteins correlate with alzheimer s disease severity
Journal of Neurochemistry, 2005Co-Authors: Irene Zagolikapitte, Olivier Boutaud, Tina S. Masterson, Ventkataraman Amarnath, Thomas J. Montine, Katrin Andreasson, John A. OatesAbstract:The formation of cyclooxygenase-derived lipid adducts of protein in brains of patients who had Alzheimer's disease has been investigated. The enzymatic product of the cyclooxygenases, prostaglandin H2, rearranges in part to highly reactive γ-Ketoaldehydes, levuglandin (LG) E2 and LGD2. These γ-Ketoaldehydes react with free amines on proteins to yield a covalent adduct. Utilizing analysis of the levuglandinyl-lysine adducts by liquid chromatography-tandem mass spectrometry, we now find that this post-translational modification is increased significantly in the hippocampus in Alzheimer's disease. The magnitude of the increase correlates with the pathological evidence of severity.
