Hydroxylation of 3-nitrotyrosine （3-NT） and 3-NT containing peptide Gly-nitroTyr-Gly in aqueous solution by hydroxyl radical were investigated with gamma irradiation. The structures of the hydroxylated products were...Hydroxylation of 3-nitrotyrosine （3-NT） and 3-NT containing peptide Gly-nitroTyr-Gly in aqueous solution by hydroxyl radical were investigated with gamma irradiation. The structures of the hydroxylated products were confirmed by electrospray ionization mass spectrometry and ^1H NMR spectrometry. The reactivity of 3-nitrotyrosine has been investigated using density functional theory （DFT） calculation.展开更多
Objective: Myeloperoxidase (MPO) is an inflammatory enzyme that is mainly released by activated neutrophils and monocytes. 3-nitrotyrosine (NT) is a stable inflammatory end product of MPO that is produced through nitr...Objective: Myeloperoxidase (MPO) is an inflammatory enzyme that is mainly released by activated neutrophils and monocytes. 3-nitrotyrosine (NT) is a stable inflammatory end product of MPO that is produced through nitrosylation of free and protein-bound tyrosines. Determination of the exact levels of free NT is technically a challenging matter. Also, there is limited information about the relationship between MPO and free NT levels and elevation of them in the plasma of patients with coronary artery disease (CAD). Therefore, we sought to determine the exact level of plasma free NT with a simple and exquisite technique in CAD patients. Methods: This study included 50 stable angina, 50 unstable angina patients, and 50 control subjects. Plasma MPO concentration was measured with an immunoassay method. Plasma free NT level was determined by a modified HPLC-fluorescence method. Lipid profile, high sensitivity C-reactive protein (hsCRP) and other clinical risk factors of patients were also assigned. Results: Plasma level of free NT was efficiently measured by the HPLC-fluorescence method. Plasma levels of MPO and NT were significantly higher in patients with stable and unstable CAD than in control subjects (P < 0.001). There was a significant correlation between the two substances in CAD patients (P < 0.001). Conclusions: We determined plasma free NT levels with a sensitive HPLC-fluorescence method with some modifications in a clinical scale. Plasma levels of MPO and NT were profoundly elevated in CAD patients. The significant relationships of the two substances and elevation of them may have useful clinical implication in patients with stable and unstable CAD.展开更多
A high glucose state readily causes peripheral axon atrophy, demyelination, loss of nerve fiber function, and delayed regeneration. However, few studies have examined whether nitration is also critical for diabetic pe...A high glucose state readily causes peripheral axon atrophy, demyelination, loss of nerve fiber function, and delayed regeneration. However, few studies have examined whether nitration is also critical for diabetic peripheral neuropathy. Therefore, this study investigated the effects of high glucose on proliferation, apoptosis, and 3-nitrotyrosine levels of Schwann cells treated with butylphthalide. In addition, we explored potential protective mechanisms of butylphthalide on peripheral nerves. Schwann cells were cultured in vitro with high glucose then stimulated with the peroxynitrite anion inhibitors uric acid and 3-n-butylphthalide for 48 hours. Cell Counting Kit-8 and flow cytometry were used to investigate the effects of uric acid and 3-n-butylphthalide on proliferation and apoptosis of Schwann cells exposed to a high glucose environment. Effects of uric acid and 3-n-butylphthalide on levels of 3-nitrotyrosine in Schwann cells were detected by enzyme-linked immunosorbent assay. The results indicated that Schwann cells cultured in high glucose showed decreased proliferation, but increased apoptosis and intracellular 3-nitrotyrosine levels. However, intervention with uric acid or 3-n-butylphthalide could increase proliferation of Schwann cells cultured in high glucose, and inhibited apoptosis and intracellular 3-nitrotyrosine levels. According to our data, 3-n-butylphthalide may inhibit cell nitrification and apoptosis, and promote cell proliferation, thereby reducing damage to Schwann cells caused by high glucose.展开更多
A novel method for the simultaneous determination of 3-nitrotyrosine(NT) and 3-chlorotyrosine(CT) in human plasma has been developed based on direct analysis in real time–tandem mass spectrometry(DART–MS/MS). Analys...A novel method for the simultaneous determination of 3-nitrotyrosine(NT) and 3-chlorotyrosine(CT) in human plasma has been developed based on direct analysis in real time–tandem mass spectrometry(DART–MS/MS). Analysis was performed in the positive ionization mode using multiple reaction monitoring(MRM) of the ion transitions at m/z 216.2/170.1 for CT, m/z 227.2/181.1 for NT and m/z 230.2/184.2 for the internal standard, d^3-NT. The assay was linear in the ranges 0.5–100 μg/m L for CT and 4–100 μg/m L for NT with corresponding limits of detection of 0.2 and 2 μg/m L. Intra- and inter-day precisions and accuracies were respectively <15% and ±15%. Matrix effects were also evaluated. The method is potentially useful for high throughput analysis although sensitivity needs to be improved before it can be applied in clinical research.展开更多
In vitro antioxidant activities of resveratrol and piceid against peroxynitrite（ONOO-） were examined by the inhibition of 3-nitrotyrosine formation.Trolox was used as a positive control.Resveratrol and piceid exhibi...In vitro antioxidant activities of resveratrol and piceid against peroxynitrite（ONOO-） were examined by the inhibition of 3-nitrotyrosine formation.Trolox was used as a positive control.Resveratrol and piceid exhibited high ONOO--scavenging activities in a concentration dependent manner.The antioxidant activities（the concentration of test compound required to yield a 50% inhibition of tyrosine nitration,IC 50） of resveratrol and piceid against ONOO-were（48.34±0.97） and（74.69±1.49） μmol/L,respectively.Compared with that of trolox[（105.40±1.16） μmol/L],their scavenging activities were 2.2-and 1.5-fold higher for resveratrol and piceid.Formation of nitroresveratrol as shown by UV-Vis spectroscopy and liquid chromatography-tandom mass spectrometry（LC-MS/MS） analysis indicates that resveratrol could directly scavenge ONOO-via nitration reaction.Our results demonstrate that foods and medicinal herbs with resveratrol and piceid as stronger ONOO-scavengers are valuable ingredients and have healthy application in preventing humans from peroxynitrite-mediated oxidative damage by scavenging peroxynitrite efficiently.展开更多
Background: To investigate the effects of unsafe decompression on rat pulmonary endothelial function and its relevant mechanisms.Methods: Sixty male Sprague-Dawley(SD) rats were randomly divided into a control group(n...Background: To investigate the effects of unsafe decompression on rat pulmonary endothelial function and its relevant mechanisms.Methods: Sixty male Sprague-Dawley(SD) rats were randomly divided into a control group(n=30) and a decompression sickness(DCS) group(n=30). The DCS model was established by placing the rats in the DCS group in a pressurized cabin where they were exposed to a 600 k Pa compressed air environment for 60 min, and the pressure was then reduced by 100 k Pa/min until it reached atmospheric pressure. After the surviving rats in the DCS group and the rats in the control group were anesthetized, their pulmonary arteries were stripped to test the in vitro pulmonary artery endothelium-dependent vasodilation capacity. Western blotting was used to measure the expression and dissociation of endothelial nitric oxide synthase(e NOS) in pulmonary artery tissues and all protein nitration levels in pulmonary artery tissues; reactive oxygen species(ROS) formation was measured via in vitro pulmonary artery superoxide anion probe dihydroethidium(DHE) staining.Results: After experiencing unsafe decompression, 10 of the 30 rats in the DCS group died. The pulmonary artery endothelium-dependent vasodilation capacity in the surviving rats decreased significantly(P<0.05). The difference in e NOS expression between the DCS group and the control group was statistically insignificant(P>0.05), but the ratio of e NOS monomer/dimer in the DCS group was significantly higher than that in the control group(P<0.05). All protein tyrosine nitration levels in the pulmonary artery tissues of the DCS group were significantly higher than those of the control group(P<0.05). The results of DHE staining showed that the amount of ROS formation in the pulmonary arteries of the DCS group was significantly higher than that of the control group(P<0.05).Conclusion: Unsafe decompression during a simulated submarine escape process can lead to e NOS dimer uncoupling in the pulmonary artery endothelium. The dissociated e NOS monomer cannot synthesize nitric oxide(NO) and thus affect the endothelium-dependent vasodilation capacity. The e NOS monomer can promote peroxynitrite(ONOO–) synthesis, leading to an increase in protein tyrosine nitration levels in pulmonary artery tissues and causing disorder in cell cycle regulation. The e NOS monomer can also cause an increase in the formation of ROS and thus mediate peroxidation damage.展开更多
Multiple sclerosis (MS) is a chronic autoimmune disorder affecting the central nervous system (CNS) through demyelination and neurodegeneration. Several lines of evidence support a role for oxidative and nitrative str...Multiple sclerosis (MS) is a chronic autoimmune disorder affecting the central nervous system (CNS) through demyelination and neurodegeneration. Several lines of evidence support a role for oxidative and nitrative stress (OS and NS) in pathogenesis of multiple sclerosis. The mechanism of influence of OS and NS on blood-brainbarrier (BBB) has critical importance for evaluating antioxidant therapies. As far as we know, markers of oxidative and nitrative stress in MS patients have been investigated independently for their relationship with the state of the blood-brain-barrier. Blood plasma samples of 58 patients with relapse-remitting MS (RRMS) with normal (Group A, n = 48, 36.2 ± 10.5 years) and damaged BBB (Group B, n = 10, 38.2 ± 11.2 years) and of 44 healthy controls (39.2 ± 14.9 years) were analyzed. TAS (total antioxidant plasma status), lipoperoxides, protein carbonyls, 3-nitrotyrosine and uric acid were evaluated in each group. Our results confirmed decreased TAS (Group A: 1.35 ± 0.55 mmol/l, P e level of lipoperoxidation positively correlated with the state of BBB (P of protein’s carbonyls (A: 0.48 ± 0.11 nmol/mg protein, P nmol/l, P ed damage to plasma proteins, what was confirmed by their positive mutual correlation (P The level of uric acid was physiological and correlated negatively with protein’s carbonyls (P 0.05) while there was no significant relationship with 3-nitotyrosine. The results suggest the role of this antioxidant in the protection of the proteins against OS what was confirmed by its positive correlation with TAS展开更多
The direct cleavage of C–NO_(2)bonds for reductive denitration of nitroarenes remains a challenging transformation in synthetic organic chemistry.Herein,we report a biocompatible palladium-deposited graphdiyne nanoca...The direct cleavage of C–NO_(2)bonds for reductive denitration of nitroarenes remains a challenging transformation in synthetic organic chemistry.Herein,we report a biocompatible palladium-deposited graphdiyne nanocatalyst(Pd@GDY/DSPE-PEG)that can catalyze reductive denitration of nitroarenes under ambient physiological conditions.Mechanistic studies support this transformation via the oxidative addition of nitroarenes with Pd(0)and subsequent ligand exchange to form arylpalladium hydride.This one-step reductive denitration via Pd@GDY/DSPE-PEG successfully facilitates the repair of the nitrated proteins arising from endogenic ONOO−and restores their physiological function,including blocking the apoptosis pathway in living cells.Moreover,Pd@GDY/DSPE-PEG was further successfully applied for catalytic denitration to reduce the level of 3-nitrotyrosine residues of proteins located in the mouse brain hippocampus in vivo.This study provides an ideal strategy for designing highly active enzymatic mimicking synthetic catalysts for the regulation of the nitrated protein level and the detoxification of nitrative damage of living cells and tissues.展开更多
基金The authors would like to thank the financial support from the National Natural Science Foundation of China （No. 20320130046） ；the Specialized Research Fund for the Doctoral Program of Higher Education （SRFDP） of M0E （No. 20030003049）.
文摘Hydroxylation of 3-nitrotyrosine （3-NT） and 3-NT containing peptide Gly-nitroTyr-Gly in aqueous solution by hydroxyl radical were investigated with gamma irradiation. The structures of the hydroxylated products were confirmed by electrospray ionization mass spectrometry and ^1H NMR spectrometry. The reactivity of 3-nitrotyrosine has been investigated using density functional theory （DFT） calculation.
文摘Objective: Myeloperoxidase (MPO) is an inflammatory enzyme that is mainly released by activated neutrophils and monocytes. 3-nitrotyrosine (NT) is a stable inflammatory end product of MPO that is produced through nitrosylation of free and protein-bound tyrosines. Determination of the exact levels of free NT is technically a challenging matter. Also, there is limited information about the relationship between MPO and free NT levels and elevation of them in the plasma of patients with coronary artery disease (CAD). Therefore, we sought to determine the exact level of plasma free NT with a simple and exquisite technique in CAD patients. Methods: This study included 50 stable angina, 50 unstable angina patients, and 50 control subjects. Plasma MPO concentration was measured with an immunoassay method. Plasma free NT level was determined by a modified HPLC-fluorescence method. Lipid profile, high sensitivity C-reactive protein (hsCRP) and other clinical risk factors of patients were also assigned. Results: Plasma level of free NT was efficiently measured by the HPLC-fluorescence method. Plasma levels of MPO and NT were significantly higher in patients with stable and unstable CAD than in control subjects (P < 0.001). There was a significant correlation between the two substances in CAD patients (P < 0.001). Conclusions: We determined plasma free NT levels with a sensitive HPLC-fluorescence method with some modifications in a clinical scale. Plasma levels of MPO and NT were profoundly elevated in CAD patients. The significant relationships of the two substances and elevation of them may have useful clinical implication in patients with stable and unstable CAD.
基金supported by the Natural Science Foundation of Anhui Province,China,No.1608085MH209(to YBW)New Medicine of University of Science and Techology of China,No.WK110000036(to YBW)
文摘A high glucose state readily causes peripheral axon atrophy, demyelination, loss of nerve fiber function, and delayed regeneration. However, few studies have examined whether nitration is also critical for diabetic peripheral neuropathy. Therefore, this study investigated the effects of high glucose on proliferation, apoptosis, and 3-nitrotyrosine levels of Schwann cells treated with butylphthalide. In addition, we explored potential protective mechanisms of butylphthalide on peripheral nerves. Schwann cells were cultured in vitro with high glucose then stimulated with the peroxynitrite anion inhibitors uric acid and 3-n-butylphthalide for 48 hours. Cell Counting Kit-8 and flow cytometry were used to investigate the effects of uric acid and 3-n-butylphthalide on proliferation and apoptosis of Schwann cells exposed to a high glucose environment. Effects of uric acid and 3-n-butylphthalide on levels of 3-nitrotyrosine in Schwann cells were detected by enzyme-linked immunosorbent assay. The results indicated that Schwann cells cultured in high glucose showed decreased proliferation, but increased apoptosis and intracellular 3-nitrotyrosine levels. However, intervention with uric acid or 3-n-butylphthalide could increase proliferation of Schwann cells cultured in high glucose, and inhibited apoptosis and intracellular 3-nitrotyrosine levels. According to our data, 3-n-butylphthalide may inhibit cell nitrification and apoptosis, and promote cell proliferation, thereby reducing damage to Schwann cells caused by high glucose.
文摘A novel method for the simultaneous determination of 3-nitrotyrosine(NT) and 3-chlorotyrosine(CT) in human plasma has been developed based on direct analysis in real time–tandem mass spectrometry(DART–MS/MS). Analysis was performed in the positive ionization mode using multiple reaction monitoring(MRM) of the ion transitions at m/z 216.2/170.1 for CT, m/z 227.2/181.1 for NT and m/z 230.2/184.2 for the internal standard, d^3-NT. The assay was linear in the ranges 0.5–100 μg/m L for CT and 4–100 μg/m L for NT with corresponding limits of detection of 0.2 and 2 μg/m L. Intra- and inter-day precisions and accuracies were respectively <15% and ±15%. Matrix effects were also evaluated. The method is potentially useful for high throughput analysis although sensitivity needs to be improved before it can be applied in clinical research.
基金Supported by the National Basic Research Program of China(Nos.2012CB721105,2011CBA00802,2007CB714301)the National Natural Science Foundation of China(No.30873400)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20090032110015)
文摘In vitro antioxidant activities of resveratrol and piceid against peroxynitrite（ONOO-） were examined by the inhibition of 3-nitrotyrosine formation.Trolox was used as a positive control.Resveratrol and piceid exhibited high ONOO--scavenging activities in a concentration dependent manner.The antioxidant activities（the concentration of test compound required to yield a 50% inhibition of tyrosine nitration,IC 50） of resveratrol and piceid against ONOO-were（48.34±0.97） and（74.69±1.49） μmol/L,respectively.Compared with that of trolox[（105.40±1.16） μmol/L],their scavenging activities were 2.2-and 1.5-fold higher for resveratrol and piceid.Formation of nitroresveratrol as shown by UV-Vis spectroscopy and liquid chromatography-tandom mass spectrometry（LC-MS/MS） analysis indicates that resveratrol could directly scavenge ONOO-via nitration reaction.Our results demonstrate that foods and medicinal herbs with resveratrol and piceid as stronger ONOO-scavengers are valuable ingredients and have healthy application in preventing humans from peroxynitrite-mediated oxidative damage by scavenging peroxynitrite efficiently.
基金supported by the Army on the Subject of China (10ZYZ219)
文摘Background: To investigate the effects of unsafe decompression on rat pulmonary endothelial function and its relevant mechanisms.Methods: Sixty male Sprague-Dawley(SD) rats were randomly divided into a control group(n=30) and a decompression sickness(DCS) group(n=30). The DCS model was established by placing the rats in the DCS group in a pressurized cabin where they were exposed to a 600 k Pa compressed air environment for 60 min, and the pressure was then reduced by 100 k Pa/min until it reached atmospheric pressure. After the surviving rats in the DCS group and the rats in the control group were anesthetized, their pulmonary arteries were stripped to test the in vitro pulmonary artery endothelium-dependent vasodilation capacity. Western blotting was used to measure the expression and dissociation of endothelial nitric oxide synthase(e NOS) in pulmonary artery tissues and all protein nitration levels in pulmonary artery tissues; reactive oxygen species(ROS) formation was measured via in vitro pulmonary artery superoxide anion probe dihydroethidium(DHE) staining.Results: After experiencing unsafe decompression, 10 of the 30 rats in the DCS group died. The pulmonary artery endothelium-dependent vasodilation capacity in the surviving rats decreased significantly(P<0.05). The difference in e NOS expression between the DCS group and the control group was statistically insignificant(P>0.05), but the ratio of e NOS monomer/dimer in the DCS group was significantly higher than that in the control group(P<0.05). All protein tyrosine nitration levels in the pulmonary artery tissues of the DCS group were significantly higher than those of the control group(P<0.05). The results of DHE staining showed that the amount of ROS formation in the pulmonary arteries of the DCS group was significantly higher than that of the control group(P<0.05).Conclusion: Unsafe decompression during a simulated submarine escape process can lead to e NOS dimer uncoupling in the pulmonary artery endothelium. The dissociated e NOS monomer cannot synthesize nitric oxide(NO) and thus affect the endothelium-dependent vasodilation capacity. The e NOS monomer can promote peroxynitrite(ONOO–) synthesis, leading to an increase in protein tyrosine nitration levels in pulmonary artery tissues and causing disorder in cell cycle regulation. The e NOS monomer can also cause an increase in the formation of ROS and thus mediate peroxidation damage.
文摘Multiple sclerosis (MS) is a chronic autoimmune disorder affecting the central nervous system (CNS) through demyelination and neurodegeneration. Several lines of evidence support a role for oxidative and nitrative stress (OS and NS) in pathogenesis of multiple sclerosis. The mechanism of influence of OS and NS on blood-brainbarrier (BBB) has critical importance for evaluating antioxidant therapies. As far as we know, markers of oxidative and nitrative stress in MS patients have been investigated independently for their relationship with the state of the blood-brain-barrier. Blood plasma samples of 58 patients with relapse-remitting MS (RRMS) with normal (Group A, n = 48, 36.2 ± 10.5 years) and damaged BBB (Group B, n = 10, 38.2 ± 11.2 years) and of 44 healthy controls (39.2 ± 14.9 years) were analyzed. TAS (total antioxidant plasma status), lipoperoxides, protein carbonyls, 3-nitrotyrosine and uric acid were evaluated in each group. Our results confirmed decreased TAS (Group A: 1.35 ± 0.55 mmol/l, P e level of lipoperoxidation positively correlated with the state of BBB (P of protein’s carbonyls (A: 0.48 ± 0.11 nmol/mg protein, P nmol/l, P ed damage to plasma proteins, what was confirmed by their positive mutual correlation (P The level of uric acid was physiological and correlated negatively with protein’s carbonyls (P 0.05) while there was no significant relationship with 3-nitotyrosine. The results suggest the role of this antioxidant in the protection of the proteins against OS what was confirmed by its positive correlation with TAS
基金support from the National Natural Science Foundation of China(grant nos.22021002,22020102005,and 22022705)the CAS-Croucher Funding Scheme for Joint Laboratories.
文摘The direct cleavage of C–NO_(2)bonds for reductive denitration of nitroarenes remains a challenging transformation in synthetic organic chemistry.Herein,we report a biocompatible palladium-deposited graphdiyne nanocatalyst(Pd@GDY/DSPE-PEG)that can catalyze reductive denitration of nitroarenes under ambient physiological conditions.Mechanistic studies support this transformation via the oxidative addition of nitroarenes with Pd(0)and subsequent ligand exchange to form arylpalladium hydride.This one-step reductive denitration via Pd@GDY/DSPE-PEG successfully facilitates the repair of the nitrated proteins arising from endogenic ONOO−and restores their physiological function,including blocking the apoptosis pathway in living cells.Moreover,Pd@GDY/DSPE-PEG was further successfully applied for catalytic denitration to reduce the level of 3-nitrotyrosine residues of proteins located in the mouse brain hippocampus in vivo.This study provides an ideal strategy for designing highly active enzymatic mimicking synthetic catalysts for the regulation of the nitrated protein level and the detoxification of nitrative damage of living cells and tissues.
