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Witucki Ł, Jakubowski H. Homocysteine metabolites inhibit autophagy by upregulating miR-21-5p, miR-155-5p, miR-216-5p, and miR-320c-3p in human vascular endothelial cells. Sci Rep 2024; 14:7151. [PMID: 38531978 DOI: 10.1038/s41598-024-57750-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 03/21/2024] [Indexed: 03/28/2024] Open
Abstract
Nutritional and genetic deficiencies in homocysteine (Hcy) metabolism lead to hyperhomocysteinemia (HHcy) and cause endothelial dysfunction, a hallmark of atherosclerosis, which is a major cause of cardiovascular disease (CVD). Impaired autophagy causes the accumulation of damaged proteins and organelles and is associated with CVD. Biochemically, HHcy is characterized by elevated levels of Hcy and its metabolites, Hcy-thiolactone and N-Hcy-protein. However, whether these metabolites can dysregulate mTOR signaling and autophagy in endothelial cells is not known. Here, we examined the influence of Hcy-thiolactone, N-Hcy-protein, and Hcy on autophagy human umbilical vein endothelial cells. We found that treatments with Hcy-thiolactone, N-Hcy-protein, or Hcy significantly downregulated beclin 1 (BECN1), autophagy-related 5 (ATG5), autophagy-related 7 (ATG7), and microtubule-associated protein 1 light chain 3 (LC3) mRNA and protein levels. We also found that these changes were mediated by upregulation by Hcy-thiolactone, N-Hcy-protein, and Hcy of autophagy-targeting microRNA (miR): miR-21, miR-155, miR-216, and miR-320c. The effects of these metabolites on levels of miR targeting autophagy as well as on the levels of BECN1, ATG5, ATG7, and LC3 mRNA and protein were abrogated by treatments with inhibitors of miR-21, miR-155, miR-216, and mir320c. Taken together, our findings show that Hcy metabolites can upregulate miR-21, miR-155, miR-216, and mir320c, which then downregulate autophagy in human endothelial cells, important for vascular homeostasis.
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Affiliation(s)
- Łukasz Witucki
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, 60-632, Poznań, Poland
| | - Hieronim Jakubowski
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, 60-632, Poznań, Poland.
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, International Center for Public Health, Rutgers University, 225 Warren Street, Newark, NJ, 07103, USA.
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Suszyńska-Zajczyk J, Witucki Ł, Perła-Kaján J, Jakubowski H. Diet-induced hyperhomocysteinemia causes sex-dependent deficiencies in offspring musculature and brain function. Front Cell Dev Biol 2024; 12:1322844. [PMID: 38559811 PMCID: PMC10979824 DOI: 10.3389/fcell.2024.1322844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 02/26/2024] [Indexed: 04/04/2024] Open
Abstract
Hyperhomocysteinemia (HHcy), characterized by elevated homocysteine (Hcy) levels, is a known risk factor for cardiovascular, renal, and neurological diseases, as well as pregnancy complications. Our study aimed to investigate whether HHcy induced by a high-methionine (high-Met) diet exacerbates cognitive and behavioral deficits in offspring and leads to other breeding problems. Dietary HHcy was induced four weeks before mating and continued throughout gestation and post-delivery. A battery of behavioral tests was conducted on offspring between postnatal days (PNDs) 5 and 30 to assess motor function/activity and cognition. The results were correlated with brain morphometric measurements and quantitative analysis of mammalian target of rapamycin (mTOR)/autophagy markers. The high-Met diet significantly increased parental and offspring urinary tHcy levels and influenced offspring behavior in a sex-dependent manner. Female offspring exhibited impaired cognition, potentially related to morphometric changes observed exclusively in HHcy females. Male HHcy pups demonstrated muscle weakness, evidenced by slower surface righting, reduced hind limb suspension (HLS) hanging time, weaker grip strength, and decreased activity in the beaker test. Western blot analyses indicated the downregulation of autophagy and the upregulation of mTOR activity in HHcy cortexes. HHcy also led to breeding impairments, including reduced breeding rate, in-utero fetal death, lower pups' body weight, and increased mortality, likely attributed to placental dysfunction associated with HHcy. In conclusion, a high-Met diet impairs memory and cognition in female juveniles and weakens muscle strength in male pups. These effects may stem from abnormal placental function affecting early neurogenesis, the dysregulation of autophagy-related pathways in the cortex, or epigenetic mechanisms of gene regulation triggered by HHcy during embryonic development.
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Affiliation(s)
- Joanna Suszyńska-Zajczyk
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznań, Poland
| | - Łukasz Witucki
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznań, Poland
| | - Joanna Perła-Kaján
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznań, Poland
| | - Hieronim Jakubowski
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznań, Poland
- Department of Microbiology, Biochemistry & Molecular Genetics, Rutgers University, New Jersey Medical School, International Center for Public Health, Newark, NJ, United States
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Colasanti T, Conti F. Autoantibody Recognition of Natural and Homocysteinylated Alpha-1 Antitrypsin: Indirect Enzyme-Linked Immunosorbent Assay (ELISA) Quantification in Sera. Methods Mol Biol 2024; 2750:135-141. [PMID: 38108974 DOI: 10.1007/978-1-0716-3605-3_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
In this chapter, indirect enzyme-linked immunosorbent assays (ELISAs) to quantitatively measure autoantibodies directed to human natural and homocysteinylated alpha-1 antitrypsin (anti-AATA and anti-HAATA, respectively) in serum are described. The illustrated ELISA protocols are slightly different, since the two protein forms have different biochemical features and, consequently, different affinity for the matrix (polystyrene microplate wells), so that specific experimental conditions have to be performed for the quantification of the serum antibody recognition.These procedures can be carried out to evaluate the anti-AATA and the anti-HAATA levels, testing serum samples, for research use.
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Affiliation(s)
- Tania Colasanti
- Rheumatology Unit, Department of Clinical Internal, Anesthesiological and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy
| | - Fabrizio Conti
- Rheumatology Unit, Department of Clinical Internal, Anesthesiological and Cardiovascular Sciences, Sapienza University of Rome, Rome, Italy
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Gospodarczyk A, Marczewski K, Gospodarczyk N, Widuch M, Tkocz M, Zalejska-Fiolka J. HOMOCYSTEINE AND CARDIOVASCULAR DISEASE - A CURRENT REVIEW. WIADOMOSCI LEKARSKIE (WARSAW, POLAND : 1960) 2022; 75:2862-2866. [PMID: 36591781 DOI: 10.36740/wlek202211224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cardiovascular diseases remain the leading cause of death worldwide for the past 20 years. Of these, ischemic heart disease has the highest mortality rate. In over 98% of cases it is caused by atherosclerosis of the coronary arteries. Homocysteine is an amino acid, containing a sulfhydryl group, which is formed as a result of the metabolism of the amino acids methionine and cysteine, which is supplied with protein-containing foods. A small amount of it is necessary for the proper functioning of the body, however, an increased concentration in blood plasma, which hyperhomocysteinemia, negatively affects blood vessels leading to the development of atherosclerosis and thrombotic com¬plications. The adverse effect on blood vessels results from various mechanisms, such as: excessive activation of Toll-like 4 receptor, activation N-methyl-d-aspartate receptors, increased production of reactive oxygen species, and impairment of nitric oxide synthesis. Elevated levels of reactive oxygen species are associated with increased expression of proinflammatory cytokines such as IL-1β, IL-6, TNF-α (tumor necrosis tumor necrosis factor), MCP-1 and intracellular adhesion molecule-1. Another factor contributing to hyperhomocysteinemia is mutation of the MTHFR gene, which in normal conditions is responsible for maintaining homocysteine levels within the normal range. People with MTHFR mutation are more prone to develop atherosclerosis and the following complications: myocardial infarction, stroke, thrombotic episodes and coronary artery disease. The aim of this paper is to present evidence supporting the role of homocysteine in the development of many cardiovascular diseases.
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Affiliation(s)
| | - Kamil Marczewski
- DEPARTMENT OF EMERGENCY MEDICINE, MEDICAL UNIVERSITY OF SILESIA, KATOWICE, POLAND
| | - Natalia Gospodarczyk
- DEPARTMENT OF EMERGENCY MEDICINE, MEDICAL UNIVERSITY OF SILESIA, KATOWICE, POLAND
| | - Michał Widuch
- DEPARTMENT OF BIOCHEMISTRY, MEDICAL UNIVERSITY OF SILESIA, KATOWICE, POLAND
| | - Michał Tkocz
- UROLOGICAL DEPARTMENT OF MUNICIPAL HOSPITAL, MEDICAL UNIVERSITY OF SILESIA, KATOWICE, POLAND
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Todorovic D, Stojanovic M, Medic A, Gopcevic K, Mutavdzin S, Stankovic S, Djuric D. Four Weeks of Aerobic Training Affects Cardiac Tissue Matrix Metalloproteinase, Lactate Dehydrogenase and Malate Dehydrogenase Enzymes Activities, and Hepatorenal Biomarkers in Experimental Hyperhomocysteinemia in Rats. Int J Mol Sci 2021; 22:ijms22136792. [PMID: 34202757 PMCID: PMC8268082 DOI: 10.3390/ijms22136792] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 06/18/2021] [Accepted: 06/22/2021] [Indexed: 12/12/2022] Open
Abstract
The aim of this study was to investigate the effect of the application of homocysteine as well as its effect under the condition of aerobic physical activity on the activities of matrix metalloproteinases (MMP), lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) in cardiac tissue and on hepato-renal biochemical parameters in sera of rats. Male Wistar albino rats were divided into four groups (n = 10, per group): C: 0.9% NaCl 0.2 mL/day subcutaneous injection (s.c.); H: homocysteine 0.45 µmol/g b.w./day s.c.; CPA saline (0.9% NaCl 0.2 mL/day s.c.) and a program of physical activity on a treadmill; and HPA homocysteine (0.45 µmol/g b.w./day s.c.) and a program of physical activity on a treadmill. Subcutaneous injection of substances was applied 2 times a day at intervals of 8 h during the first two weeks of experimental protocol. Hcy level in serum was significantly higher in the HPA group compared to the CPA group (p < 0.05). Levels of glucose, proteins, albumin, and hepatorenal biomarkers were higher in active groups compared with the sedentary group. It was demonstrated that the increased activities of LDH (mainly caused by higher activity of isoform LDH2) and mMDH were found under the condition of homocysteine-treated rats plus aerobic physical activity. Independent application of homocysteine did not lead to these changes. Physical activity leads to activation of MMP-2 isoform and to increased activity of MMP-9 isoform in both homocysteine-treated and control rats.
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Affiliation(s)
- Dusan Todorovic
- Faculty of Medicine, Institute of Medical Physiology “Richard Burian”, University of Belgrade, 11000 Belgrade, Serbia; (D.T.); (M.S.); (S.M.)
| | - Marija Stojanovic
- Faculty of Medicine, Institute of Medical Physiology “Richard Burian”, University of Belgrade, 11000 Belgrade, Serbia; (D.T.); (M.S.); (S.M.)
| | - Ana Medic
- Faculty of Medicine, Institute of Chemistry in Medicine “Prof. Dr. Petar Matavulj”, University of Belgrade, 11000 Belgrade, Serbia; (A.M.); (K.G.)
| | - Kristina Gopcevic
- Faculty of Medicine, Institute of Chemistry in Medicine “Prof. Dr. Petar Matavulj”, University of Belgrade, 11000 Belgrade, Serbia; (A.M.); (K.G.)
| | - Slavica Mutavdzin
- Faculty of Medicine, Institute of Medical Physiology “Richard Burian”, University of Belgrade, 11000 Belgrade, Serbia; (D.T.); (M.S.); (S.M.)
| | - Sanja Stankovic
- Centre of Medical Biochemistry, Clinical Centre of Serbia, 11000 Belgrade, Serbia;
| | - Dragan Djuric
- Faculty of Medicine, Institute of Medical Physiology “Richard Burian”, University of Belgrade, 11000 Belgrade, Serbia; (D.T.); (M.S.); (S.M.)
- Correspondence:
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Balint B, Hergalant S, Camadro JM, Blaise S, Vanalderwiert L, Lignières L, Guéant-Rodriguez RM, Guéant JL. Fetal Programming by Methyl Donor Deficiency Produces Pathological Remodeling of the Ascending Aorta. Arterioscler Thromb Vasc Biol 2021; 41:1928-1941. [PMID: 33827257 DOI: 10.1161/atvbaha.120.315587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Brittany Balint
- UMR Inserm 1256 N-GERE (Nutrition, Génetique et Exposition aux Risques Environmentaux) (B.B., S.H., R.-M.G.-R., J.-L.G.), Université de Lorraine, France
| | - Sébastien Hergalant
- UMR Inserm 1256 N-GERE (Nutrition, Génetique et Exposition aux Risques Environmentaux) (B.B., S.H., R.-M.G.-R., J.-L.G.), Université de Lorraine, France
| | - Jean-Michel Camadro
- Mass Spectrometry Laboratory, Institut Jacques Monod, UMR 7592, Université Paris Diderot, CNRS, Sorbonne Paris Cité, France (J.-M.C., L.L.)
| | | | | | - Laurent Lignières
- Mass Spectrometry Laboratory, Institut Jacques Monod, UMR 7592, Université Paris Diderot, CNRS, Sorbonne Paris Cité, France (J.-M.C., L.L.)
| | - Rosa-Maria Guéant-Rodriguez
- UMR Inserm 1256 N-GERE (Nutrition, Génetique et Exposition aux Risques Environmentaux) (B.B., S.H., R.-M.G.-R., J.-L.G.), Université de Lorraine, France
- Department of Molecular Medicine and National Center of Inborn Errors of Metabolism, University Hospital Center (R.-M.G.-R., J.-L.G.), Université de Lorraine, France
| | - Jean-Louis Guéant
- UMR Inserm 1256 N-GERE (Nutrition, Génetique et Exposition aux Risques Environmentaux) (B.B., S.H., R.-M.G.-R., J.-L.G.), Université de Lorraine, France
- Department of Molecular Medicine and National Center of Inborn Errors of Metabolism, University Hospital Center (R.-M.G.-R., J.-L.G.), Université de Lorraine, France
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7
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Colasanti T, Sabatinelli D, Mancone C, Giorgi A, Pecani A, Spinelli FR, Di Giamberardino A, Navarini L, Speziali M, Vomero M, Barbati C, Perricone C, Ceccarelli F, Finucci A, Celia AI, Currado D, Afeltra A, Schininà ME, Barnaba V, Conti F, Valesini G, Alessandri C. Homocysteinylated alpha 1 antitrypsin as an antigenic target of autoantibodies in seronegative rheumatoid arthritis patients. J Autoimmun 2020; 113:102470. [DOI: 10.1016/j.jaut.2020.102470] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/18/2020] [Accepted: 04/19/2020] [Indexed: 12/21/2022]
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Mechanisms of homocysteine-induced damage to the endothelial, medial and adventitial layers of the arterial wall. Biochimie 2020; 173:100-106. [PMID: 32105811 DOI: 10.1016/j.biochi.2020.02.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/20/2020] [Indexed: 11/23/2022]
Abstract
Homocysteine (Hcy) is a non-protein forming amino acid which is the direct metabolic precursor of methionine. Increased concentration of serum Hcy is considered a risk factor for cardiovascular disease and is specifically linked to various diseases of the vasculature. Serum Hcy is associated with atherosclerosis, hypertension and aneurysms of the aorta in humans, though the precise mechanisms by which Hcy contributes to these conditions remain elusive. Results from clinical trials that successfully lowered serum Hcy without reducing features of vascular disease in cardiovascular patients have cast doubt on whether or not Hcy directly impacts the vasculature. However, studies in animals and in cell culture suggest that Hcy has a vast array of toxic effects on the vasculature, with demonstrated roles in endothelial dysfunction, medial remodeling and adventitial inflammation. It is hypothesized that rather than serum Hcy, tissue-bound Hcy and the incorporation of Hcy into proteins could underlie the toxic effects of Hcy on the vasculature. In this review, we present evidence for Hcy-associated vascular disease in humans, and we critically examine the possible mechanisms by which Hcy specifically impacts the endothelial, medial and adventitial layers of the arterial wall. Deciphering the mechanisms by which Hcy interacts with proteins in the arterial wall will allow for a better understanding of the pathomechanisms of hyperhomocysteinemia and will help to define a better means of prevention at the appropriate window of life.
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9
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Reddy VS, Trinath J, Reddy GB. Implication of homocysteine in protein quality control processes. Biochimie 2019; 165:19-31. [PMID: 31269461 DOI: 10.1016/j.biochi.2019.06.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/26/2019] [Indexed: 12/22/2022]
Abstract
Homocysteine (Hcy) is a key metabolite generated during methionine metabolism. The elevated levels of Hcy in the blood are reffered to as hyperhomocystenimeia (HHcy). The HHcy is caused by impaired metabolism/deficiency of either folate or B12 or defects in Hcy metabolism. Accumulating evidence suggests that HHcy is associated with cardiovascular and brain diseases including atherosclerosis, endothelial injury, and stroke etc. Vitamin B12 (cobalamin; B12) is a water-soluble vitamin essential for two metabolic reactions. It acts as a co-factor for methionine synthase and L-methylmalonyl-CoA mutase. Besides, it is also vital for DNA synthesis and maturation of RBC. Deficiency of B12 is associated with haematological and neurological disorders. Hyperhomocysteinemia (HHcy)-induced toxicity is thought to be mediated by the accumulation of Hcy and its metabolites, homocysteinylated proteins. Cellular protein quality control (PQC) is essential for the maintenance of proteome integrity, and cell viability and its failure contributes to the development of multiple diseases. Chaperones, unfolded protein response (UPR), ubiquitin-proteasome system (UPS), and autophagy are analogous strategies of PQC that maintain cellular proteome integrity. Recently, multiple studies reported that HHcy responsible for perturbation of PQC by reducing chaperone levels, activating UPR, and impairing autophagy. Besides, HHcy also induce cytotoxicity, inflammation, protein aggregation and apoptosis. It has been shown that some of the factors including altered SIRT1-HSF1 axis and irreversible homocysteinylation of proteins are responsible for folate and/or B12 deficiency or HHcy-induced impairment of PQC. Therefore, this review highlights the current understanding of HHcy in the context of cellular PQC and their pathophysiological and clinical consequences, epigenomic changes, therapeutic implications of B12, and chemical chaperones based on cell culture and experimental animal models.
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Affiliation(s)
- V Sudhakar Reddy
- Biochemistry Division, National Institute of Nutrition, Hyderabad, India.
| | - Jamma Trinath
- Department of Biological Sciences, BITS-Pilani, 500078, Hyderabad Campus, Hyderabad, Telangana, India
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Jakubowski H. Homocysteine Modification in Protein Structure/Function and Human Disease. Physiol Rev 2019; 99:555-604. [PMID: 30427275 DOI: 10.1152/physrev.00003.2018] [Citation(s) in RCA: 152] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Epidemiological studies established that elevated homocysteine, an important intermediate in folate, vitamin B12, and one carbon metabolism, is associated with poor health, including heart and brain diseases. Earlier studies show that patients with severe hyperhomocysteinemia, first identified in the 1960s, exhibit neurological and cardiovascular abnormalities and premature death due to vascular complications. Although homocysteine is considered to be a nonprotein amino acid, studies over the past 2 decades have led to discoveries of protein-related homocysteine metabolism and mechanisms by which homocysteine can become a component of proteins. Homocysteine-containing proteins lose their biological function and acquire cytotoxic, proinflammatory, proatherothrombotic, and proneuropathic properties, which can account for the various disease phenotypes associated with hyperhomocysteinemia. This review describes mechanisms by which hyperhomocysteinemia affects cellular proteostasis, provides a comprehensive account of the biological chemistry of homocysteine-containing proteins, and discusses pathophysiological consequences and clinical implications of their formation.
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Affiliation(s)
- Hieronim Jakubowski
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers-New Jersey Medical School, International Center for Public Health , Newark, New Jersey ; and Department of Biochemistry and Biotechnology, Poznań University of Life Sciences , Poznań , Poland
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11
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Borowczyk K, Piechocka J, Głowacki R, Dhar I, Midtun Ø, Tell GS, Ueland PM, Nygård O, Jakubowski H. Urinary excretion of homocysteine thiolactone and the risk of acute myocardial infarction in coronary artery disease patients: the WENBIT trial. J Intern Med 2019; 285:232-244. [PMID: 30193001 PMCID: PMC6378604 DOI: 10.1111/joim.12834] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES No individual homocysteine (Hcy) metabolite has been studied as a risk marker for coronary artery disease (CAD). Our objective was to examine Hcy-thiolactone, a chemically reactive metabolite generated by methionyl-tRNA synthetase and cleared by the kidney, as a risk predictor of incident acute myocardial infarction (AMI) in the Western Norway B-Vitamin Intervention Trial. DESIGN Single centre, prospective double-blind clinical intervention study, randomized in a 2 × 2 factorial design. SUBJECTS AND METHODS Patients with suspected CAD (n = 2049, 69.8% men; 61.2-year-old) were randomized to groups receiving daily (i) folic acid (0.8 mg)/vitamin B12 (0.4 mg)/vitamin B6 (40 mg); (ii) folic acid/vitamin B12 ; (iii) vitamin B6 or (iv) placebo. Urinary Hcy-thiolactone was quantified at baseline, 12 and 38 months. RESULTS Baseline urinary Hcy-thiolactone/creatinine was significantly associated with plasma tHcy, ApoA1, glomerular filtration rate, potassium and pyridoxal 5'-phosphate (positively) and with age, hypertension, smoking, urinary creatinine, plasma bilirubin and kynurenine (negatively). During median 4.7-years, 183 patients (8.9%) suffered an AMI. In Cox regression analysis, Hcy-thiolactone/creatinine was associated with AMI risk (hazard ratio = 1.58, 95% confidence interval = 1.10-2.26, P = 0.012 for trend; adjusted for age, gender, tHcy). This association was confined to patients with pyridoxic acid below median (adjusted HR = 2.72, 95% CI = 1.47-5.03, P = 0.0001; Pinteraction = 0.020). B-vitamin/folate treatments did not affect Hcy-thiolactone/creatinine and its AMI risk association. CONCLUSIONS Hcy-thiolactone/creatinine ratio is a novel AMI risk predictor in patients with suspected CAD, independent of traditional risk factors and tHcy, but modified by vitamin B6 catabolism. These findings lend a support to the hypothesis that Hcy-thiolactone is mechanistically involved in cardiovascular disease.
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Affiliation(s)
- K Borowczyk
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers-New Jersey Medical School, International Center for Public Health, Newark, NJ, USA.,Department of Environmental Chemistry, Faculty of Chemistry, University of Łódź, Łódź, Poland
| | - J Piechocka
- Department of Environmental Chemistry, Faculty of Chemistry, University of Łódź, Łódź, Poland
| | - R Głowacki
- Department of Environmental Chemistry, Faculty of Chemistry, University of Łódź, Łódź, Poland
| | - I Dhar
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | | | - G S Tell
- Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.,Division of Mental and Physical Health, Norwegian Institute of Public Health, Bergen, Norway
| | - P M Ueland
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - O Nygård
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Department of Heart Disease, Haukeland University Hospital, Institute of Medicine, University of Bergen, Bergen, Norway
| | - H Jakubowski
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers-New Jersey Medical School, International Center for Public Health, Newark, NJ, USA.,Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznań, Poland
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Comparison of Protein N-Homocysteinylation in Rat Plasma under Elevated Homocysteine Using a Specific Chemical Labeling Method. Molecules 2016; 21:molecules21091195. [PMID: 27617989 PMCID: PMC5292613 DOI: 10.3390/molecules21091195] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 09/02/2016] [Accepted: 09/05/2016] [Indexed: 11/30/2022] Open
Abstract
Elevated blood concentrations of homocysteine have been well established as a risk factor for cardiovascular diseases and neuropsychiatric diseases, yet the etiologic relationship of homocysteine to these disorders remains poorly understood. Protein N-homocysteinylation has been hypothesized as a contributing factor; however, it has not been examined globally owing to the lack of suitable detection methods. We recently developed a selective chemical method to label N-homocysteinylated proteins with a biotin-aldehyde tag followed by Western blotting analysis, which was further optimized in this study. We then investigated the variation of protein N-homocysteinylation in plasma from rats on a vitamin B12 deficient diet. Elevated “total homocysteine” concentrations were determined in rats with a vitamin B12 deficient diet. Correspondingly, overall levels of plasma protein N-homocysteinylation displayed an increased trend, and furthermore, more pronounced and statistically significant changes (e.g., 1.8-fold, p-value: 0.03) were observed for some individual protein bands. Our results suggest that, as expected, a general metabolic correlation exists between “total homocysteine” and N-homocysteinylation, although other factors are involved in homocysteine/homocysteine thiolactone metabolism, such as the transsulfuration of homocysteine by cystathionine β-synthase or the hydrolysis of homocysteine thiolactone by paraoxonase 1 (PON1), may play more significant or direct roles in determining the level of N-homocysteinylation.
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13
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Jakubowski H. Quantification of urinary S- and N-homocysteinylated protein and homocysteine-thiolactone in mice. Anal Biochem 2016; 508:118-23. [DOI: 10.1016/j.ab.2016.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/31/2016] [Accepted: 06/01/2016] [Indexed: 12/22/2022]
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Perła-Kajan J, Utyro O, Rusek M, Malinowska A, Sitkiewicz E, Jakubowski H. N-Homocysteinylation impairs collagen cross-linking in cystathionine β-synthase-deficient mice: a novel mechanism of connective tissue abnormalities. FASEB J 2016; 30:3810-3821. [PMID: 27530978 DOI: 10.1096/fj.201600539] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/27/2016] [Indexed: 02/04/2023]
Abstract
Cystathionine β-synthase (CBS) deficiency, a genetic disorder in homocysteine (Hcy) metabolism in humans, elevates plasma Hcy-thiolactone and leads to connective tissue abnormalities that affect the cardiovascular and skeletal systems. However, the underlying mechanism of these abnormalities is not understood. Hcy-thiolactone has the ability to form isopeptide bonds with protein lysine residues, which generates N-homocysteinylated protein. Because lysine residues are involved in collagen cross-linking, N-homocysteinylation of these lysines should impair cross-linking. Using a Tg-I278T Cbs-/- mouse model of hyperhomocysteinemia (HHcy) which replicates the connective tissue abnormalities observed in CBS-deficient patients, we found that N-Hcy-collagen was elevated in bone, tail, and heart of Cbs-/- mice, whereas pyridinoline cross-links were significantly reduced. Plasma deoxypyridinoline cross-link and cross-linked carboxyterminal telopeptide of type I collagen were also significantly reduced in the Cbs-/- mice. Lysine oxidase activity and mRNA level were not reduced by the Cbs-/- genotype. We also showed that collagen carries S-linked Hcy bound to the thiol of N-linked Hcy. In vitro experiments showed that Hcy-thiolactone modifies lysine residues in collagen type I α-1 chain. Residue K160, located in the nonhelical N-telopeptide region and involved in pyridinoline cross-link formation, was also N-homocysteinylated in vivo Taken together, our findings showed that N-homocysteinylation of collagen in Cbs-/- mice impairs its cross-linking. These findings explain, at least in part, connective tissue abnormalities observed in HHcy.-Perła-Kajan, J., Utyro, O., Rusek, M., Malinowska, A., Sitkiewicz, E., Jakubowski, H. N-Homocysteinylation impairs collagen cross-linking in cystathionine β-synthase-deficient mice: a novel mechanism of connective tissue abnormalities.
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Affiliation(s)
- Joanna Perła-Kajan
- Department of Biochemistry and Biotechnology, University of Life Sciences, Poznań, Poland
| | - Olga Utyro
- Institute of Bioorganic Chemistry, Poznań, Poland
| | - Marta Rusek
- Department of Microbiology, Biochemistry and Molecular Genetics, International Center for Public Health, Rutgers-New Jersey Medical School, Rutgers University, Newark, New Jersey, USA; and
| | - Agata Malinowska
- Proteomics Laboratory, Biophysics Department, Institute of Biochemistry and Biophysics, Warsaw, Poland
| | - Ewa Sitkiewicz
- Proteomics Laboratory, Biophysics Department, Institute of Biochemistry and Biophysics, Warsaw, Poland
| | - Hieronim Jakubowski
- Department of Biochemistry and Biotechnology, University of Life Sciences, Poznań, Poland; .,Institute of Bioorganic Chemistry, Poznań, Poland.,Department of Microbiology, Biochemistry and Molecular Genetics, International Center for Public Health, Rutgers-New Jersey Medical School, Rutgers University, Newark, New Jersey, USA; and
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15
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Denny KJ, Kelly CF, Kumar V, Witham KL, Cabrera RM, Finnell RH, Taylor SM, Jeanes A, Woodruff TM. Autoantibodies against homocysteinylated protein in a mouse model of folate deficiency-induced neural tube defects. ACTA ACUST UNITED AC 2016; 106:201-7. [PMID: 26900104 DOI: 10.1002/bdra.23483] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Periconceptional supplementation with folic acid results in a significant reduction in the incidence of neural tube defects (NTDs). Nonetheless, NTDs remain a leading cause of perinatal morbidity and mortality worldwide, and the mechanism(s) by which folate exerts its protective effects are unknown. Homocysteine is an amino acid that accumulates under conditions of folate-deficiency, and is suggested as a risk factor for NTDs. One proposed mechanism of homocysteine toxicity is its accumulation into proteins in a process termed homocysteinylation. METHODS & RESULTS Herein, we used a folate-deficient diet in pregnant mice to demonstrate that there is: (i) a significant inverse correlation between maternal serum folate levels and serum homocysteine; (ii) a significant positive correlation between serum homocysteine levels and titers of autoantibodies against homocysteinylated protein; and (iii) a significant increase in congenital malformations and NTDs in mice deficient in serum folate. Furthermore, in mice administered the folate-deplete diet before conception, supplementation with folic acid during the gestational period completely rescued the embryos from congenital defects, and resulted in homocysteinylated protein titers at term that are comparable to that of mice administered a folate-replete diet throughout both the pre- and postconception period. These results demonstrate that a low-folate diet that induces NTDs also increases protein homocysteinylation and the subsequent generation of autoantibodies against homocysteinylated proteins. CONCLUSION These data support the hypotheses that homocysteinylation results in neo-self antigen formation under conditions of maternal folate deficiency, and that this process is reversible with folic acid supplementation.
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Affiliation(s)
- Kerina J Denny
- School of Biomedical Sciences, University of Queensland, Brisbane, Australia.,School of Medicine, University of Queensland, Brisbane, Australia
| | - Christina F Kelly
- School of Biomedical Sciences, University of Queensland, Brisbane, Australia
| | - Vinod Kumar
- School of Biomedical Sciences, University of Queensland, Brisbane, Australia
| | - Katey L Witham
- School of Biomedical Sciences, University of Queensland, Brisbane, Australia
| | - Robert M Cabrera
- Department of Nutritional Sciences, The University of Texas, Austin, Texas
| | - Richard H Finnell
- Department of Nutritional Sciences, The University of Texas, Austin, Texas
| | - Stephen M Taylor
- School of Biomedical Sciences, University of Queensland, Brisbane, Australia
| | - Angela Jeanes
- School of Biomedical Sciences, University of Queensland, Brisbane, Australia
| | - Trent M Woodruff
- School of Biomedical Sciences, University of Queensland, Brisbane, Australia
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16
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Homocysteine thiolactone and N-homocysteinylated protein induce pro-atherogenic changes in gene expression in human vascular endothelial cells. Amino Acids 2015; 47:1319-39. [PMID: 25802182 PMCID: PMC4458266 DOI: 10.1007/s00726-015-1956-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/04/2015] [Indexed: 12/11/2022]
Abstract
Genetic or nutritional deficiencies in homocysteine (Hcy) metabolism lead to hyperhomocysteinemia (HHcy) and cause endothelial dysfunction, a hallmark of atherosclerosis. In addition to Hcy, related metabolites accumulate in HHcy but their role in endothelial dysfunction is unknown. Here, we examine how Hcy-thiolactone, N-Hcy-protein, and Hcy affect gene expression and molecular pathways in human umbilical vein endothelial cells. We used microarray technology, real-time quantitative polymerase chain reaction, and bioinformatic analysis with PANTHER, DAVID, and Ingenuity Pathway Analysis (IPA) resources. We identified 47, 113, and 30 mRNAs regulated by N-Hcy-protein, Hcy-thiolactone, and Hcy, respectively, and found that each metabolite induced a unique pattern of gene expression. Top molecular pathways affected by Hcy-thiolactone were chromatin organization, one-carbon metabolism, and lipid-related processes [−log(P value) = 20–31]. Top pathways affected by N-Hcy-protein and Hcy were blood coagulation, sulfur amino acid metabolism, and lipid metabolism [−log(P value)] = 4–11; also affected by Hcy-thiolactone, [−log(P value) = 8–14]. Top disease related to Hcy-thiolactone, N-Hcy-protein, and Hcy was ‘atherosclerosis, coronary heart disease’ [−log(P value) = 9–16]. Top-scored biological networks affected by Hcy-thiolactone (score = 34–40) were cardiovascular disease and function; those affected by N-Hcy-protein (score = 24–35) were ‘small molecule biochemistry, neurological disease,’ and ‘cardiovascular system development and function’; and those affected by Hcy (score = 25–37) were ‘amino acid metabolism, lipid metabolism,’ ‘cellular movement, and cardiovascular and nervous system development and function.’ These results indicate that each Hcy metabolite uniquely modulates gene expression in pathways important for vascular homeostasis and identify new genes and pathways that are linked to HHcy-induced endothelial dysfunction and vascular disease.
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17
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Eksin E, Erdem A. Electrochemical detection of N-homocysteinylated BSA in the fetal bovine serum medium. RSC Adv 2015. [DOI: 10.1039/c4ra13303j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The immobilization of bovine serum albumin (BSA), homocysteine-thiolactone (HTL) andN-homocysteinylated BSA (N-Hcy-BSA) onto the surface of each PGE was performed by passive adsorption and the electrochemical detection of these components was investigated individually.
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Affiliation(s)
- Ece Eksin
- Ege University
- Faculty of Pharmacy
- Analytical Chemistry Department
- Izmir
- Turkey
| | - Arzum Erdem
- Ege University
- Faculty of Pharmacy
- Analytical Chemistry Department
- Izmir
- Turkey
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18
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The application of a chemical determination of N-homocysteinylation levels in developing mouse embryos: implication for folate responsive birth defects. J Nutr Biochem 2014; 26:312-8. [PMID: 25620692 DOI: 10.1016/j.jnutbio.2014.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Revised: 09/24/2014] [Accepted: 10/07/2014] [Indexed: 12/19/2022]
Abstract
Elevated homocysteine levels have long been associated with various disease states, including cardiovascular disease and birth defects, including neural tube defects (NTDs). One hypothesis regarding the strong correlation between these various disorders and high levels of homocysteine is that a reactive form of this small molecule can attach to mammalian proteins in a phenomenon known as homocysteinylation. These posttranslational modifications may become antigenic or may even directly disrupt certain protein function. It remains to be determined whether dietary influences that can cause globally increased levels of circulating homocysteine confer negative effects maternally, or may otherwise negatively and materially impact the metabolic balance in developing embryos. Herein we present the application of a chemical method of determination of N-homocysteinylation to a set of neural tube closure stage mouse embryos and their mothers. We explore the uses of this newly described technique to investigate levels of maternal and embryonic N-homocysteinylation using dietary manipulations of one-carbon metabolism with two known folate-responsive NTD mouse models. The data presented reveal that although diet appeared to have significant effects on the maternal metabolic status, those effects did not directly correlate to the embryonic folate or N-homocysteinylation status. Our studies indicate that maternal diet and embryonic genotype most significantly affected the embryonic developmental outcome.
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19
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Identification of N-homocysteinylation sites in plasma proteins. Amino Acids 2013; 46:235-44. [DOI: 10.1007/s00726-013-1617-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 10/29/2013] [Indexed: 11/27/2022]
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20
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Jakubowski H. The Mechanism and Consequences of Homocysteine Incorporation Into Protein in Humans. PHOSPHORUS SULFUR 2013. [DOI: 10.1080/10426507.2012.736104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Hieronim Jakubowski
- a Department of Microbiology & Molecular Genetics, UMDNJ-New Jersey Medical School , International Center for Public Health , Newark , NJ , USA
- b Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, and Department of Biochemistry and Biotechnology , University of Life Sciences , Poznań , Poland
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21
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Borowczyk K, Shih DM, Jakubowski H. Metabolism and neurotoxicity of homocysteine thiolactone in mice: evidence for a protective role of paraoxonase 1. J Alzheimers Dis 2012; 30:225-31. [PMID: 22406444 DOI: 10.3233/jad-2012-111940] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Homocysteine (Hcy)-thiolactone is toxic, induces epileptic seizures in rodents, and has been implicated in Alzheimer's disease. Paraoxonase 1 (Pon1), a component of high-density lipoprotein, hydrolyzes Hcy-thiolactone in vitro. Whether this reflects a physiological function and whether Pon1 can protect against Hcy-thiolactone toxicity was unknown. Here we show that Hcy-thiolactone was elevated in brains of Pon1-/- mice (1.5-fold, p = 0.047) and that Pon1-/- mice excrete more Hcy-thiolactone than wild type animals (2.4-fold, p = 0.047). The frequency of seizures induced by intraperitoneal injections of L-Hcy-thiolactone was significantly higher in Pon1-/- mice compared with wild type animals (52.8% versus 29.5%, p = 0.042); the latency of seizures was lower in Pon1-/- mice than in wild type animals (31.8 min versus 41.2 min, p = 0.019). Using the Pon1 null mice, we provide the first direct evidence that a specific Hcy metabolite, Hcy-thiolactone, rather than Hcy itself is neurotoxic in vivo. Our findings indicate that Pon1 protects mice against Hcy-thiolactone neurotoxicity by hydrolyzing it in the brain, and suggest a mechanism by which Pon1 can protect against neurodegeneration associated with hyperhomocysteinemia and Alzheimer's disease.
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Affiliation(s)
- Kamila Borowczyk
- Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, International Center for Public Health, Newark, NJ 07101, USA
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22
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Perła-Kaján J, Jakubowski H. Paraoxonase 1 and homocysteine metabolism. Amino Acids 2012; 43:1405-17. [PMID: 22643843 DOI: 10.1007/s00726-012-1321-z] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 05/04/2012] [Indexed: 01/23/2023]
Abstract
Paraoxonase 1 (PON1), a component of high-density lipoprotein (HDL), is a calcium-dependent multifunctional enzyme that connects metabolisms of lipoproteins and homocysteine (Hcy). Both PON1 and Hcy have been implicated in human diseases, including atherosclerosis and neurodegeneration. The involvement of Hcy in disease could be mediated through its interactions with PON1. Due to its ability to reduce oxidative stress, PON1 contributes to atheroprotective functions of HDL in mice and humans. Although PON1 has the ability to hydrolyze a variety of substrates, only one of them-Hcy-thiolactone-is known to occur naturally. In humans and mice, Hcy-thiolactonase activity of PON1 protects against N-homocysteinylation, which is detrimental to protein structure and function. PON1 also protects against neurotoxicity associated with hyperhomocysteinemia in mouse models. The links between PON1 and Hcy in relation to pathological states such as coronary artery disease, stroke, diabetic mellitus, kidney failure and Alzheimer's disease that emerge from recent studies are the topics of this review.
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Affiliation(s)
- Joanna Perła-Kaján
- Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, Poznan, Poland.
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23
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She ZG, Chen HZ, Yan Y, Li H, Liu DP. The human paraoxonase gene cluster as a target in the treatment of atherosclerosis. Antioxid Redox Signal 2012; 16:597-632. [PMID: 21867409 PMCID: PMC3270057 DOI: 10.1089/ars.2010.3774] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The paraoxonase (PON) gene cluster contains three adjacent gene members, PON1, PON2, and PON3. Originating from the same fungus lactonase precursor, all of the three PON genes share high sequence identity and a similar β propeller protein structure. PON1 and PON3 are primarily expressed in the liver and secreted into the serum upon expression, whereas PON2 is ubiquitously expressed and remains inside the cell. Each PON member has high catalytic activity toward corresponding artificial organophosphate, and all exhibit activities to lactones. Therefore, all three members of the family are regarded as lactonases. Under physiological conditions, they act to degrade metabolites of polyunsaturated fatty acids and homocysteine (Hcy) thiolactone, among other compounds. By detoxifying both oxidized low-density lipoprotein and Hcy thiolactone, PONs protect against atherosclerosis and coronary artery diseases, as has been illustrated by many types of in vitro and in vivo experimental evidence. Clinical observations focusing on gene polymorphisms also indicate that PON1, PON2, and PON3 are protective against coronary artery disease. Many other conditions, such as diabetes, metabolic syndrome, and aging, have been shown to relate to PONs. The abundance and/or activity of PONs can be regulated by lipoproteins and their metabolites, biological macromolecules, pharmacological treatments, dietary factors, and lifestyle. In conclusion, both previous results and ongoing studies provide evidence, making the PON cluster a prospective target for the treatment of atherosclerosis.
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Affiliation(s)
- Zhi-Gang She
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
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Borowczyk K, Tisończyk J, Jakubowski H. Metabolism and neurotoxicity of homocysteine thiolactone in mice: protective role of bleomycin hydrolase. Amino Acids 2012; 43:1339-48. [PMID: 22227865 DOI: 10.1007/s00726-011-1207-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 12/21/2011] [Indexed: 10/14/2022]
Abstract
Genetic or nutritional disorders in homocysteine (Hcy) metabolism elevate Hcy-thiolactone and cause heart and brain diseases. Hcy-thiolactone has been implicated in these diseases because it has the ability to modify protein lysine residues and generate toxic N-Hcy-proteins with auto-immunogenic, pro-thrombotic, and amyloidogenic properties. Bleomycin hydrolase (Blmh) has the ability to hydrolyze L-Hcy-thiolactone (but not D-Hcy-thiolactone) to Hcy in vitro, but whether this reflects a physiological function has been unknown. Here, we show that Blmh (-/-) mice excreted in urine 1.8-fold more Hcy-thiolactone than wild-type Blmh (+/+) animals (P = 0.02). Hcy-thiolactone was elevated 2.3-fold in brains (P = 0.004) and 2.0-fold in kidneys (P = 0.047) of Blmh (-/-) mice relative to Blmh (+/+) animals. Plasma N-Hcy-protein was elevated in Blmh (-/-) mice fed a normal (2.3-fold, P < 0.001) or hyperhomocysteinemic diet (1.5-fold, P < 0.001), compared with Blmh (+/+) animals. More intraperitoneally injected L-Hcy-thiolactone was recovered in plasma in Blmh (-/-) mice than in wild-type Blmh (+/+) animals (83.1 vs. 39.3 μM, P < 0.0001). In Blmh (+/+) mice injected intraperitoneally with D-Hcy-thiolactone, D,L-Hcy-thiolactone, or L-Hcy-thiolactone, 88, 47, or 6.3%, respectively, of the injected dose was recovered in plasma. The incidence of seizures induced by L-Hcy-thiolactone injections (3,700 nmol/g body weight) was higher in Blmh (-/-) than in Blmh (+/+) mice (93.8 vs. 29.5%, P < 0.001). Using the Blmh null mice, we provide the first direct evidence that a specific Hcy metabolite, Hcy-thiolactone, rather than Hcy itself, is neurotoxic in vivo. Taken together, our findings indicate that Blmh protects mice against L-Hcy-thiolactone toxicity by metabolizing it to Hcy and suggest a mechanism by which Blmh might protect against neurodegeneration associated with hyperhomocysteinemia and Alzheimer's disease.
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Affiliation(s)
- Kamila Borowczyk
- Department of Microbiology and Molecular Genetics, International Center for Public Health, UMDNJ-New Jersey Medical School, 225 Warren Street, Newark, NJ 07101, USA
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Tetrahydrocurcumin ameliorates homocysteinylated cytochrome-c mediated autophagy in hyperhomocysteinemia mice after cerebral ischemia. J Mol Neurosci 2012; 47:128-38. [PMID: 22212488 DOI: 10.1007/s12031-011-9695-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 12/08/2011] [Indexed: 12/21/2022]
Abstract
High levels of homocysteine (Hcy) known as hyperhomocysteinemia (HHcy), contribute to autophagy and ischemia/reperfusion injury (I/R). Previous studies have shown that I/R injury and HHcy cause increased cerebrovascular permeability; however, the associated mechanism remains obscure. Interestingly, during HHcy, cytochome-c becomes homocysteinylated (Hcy-cyto-c). Cytochrome-c (cyto-c) transports electrons and facilitates bioenergetics in the system. However, its role in autophagy during ischemia/reperfusion injury is unclear. Tetrahydrocurcumin (THC) is a major herbal antioxidant and anti-inflammatory agent. Therefore, the objective of this study was to determine whether THC ameliorates autophagy during ischemia/reperfusion injury by reducing homocysteinylation of cyto-c in hyperhomocysteinemia pathological condition. To test this hypothesis, we employed 8-10-week-old male cystathionine-beta-synthase heterozygote knockout (CBS⁺/⁻) mice (genetically hyperhomocystemic mice). Experimental group was: CBS⁺/⁻, CBS⁺/⁻ + THC (25 mg/kg in 0.1% DMSO dose); CBS ⁺/⁻/I/R, and CBS⁺/⁻/I/R + THC (25 mg/kg in 0.1% DMSO dose). Ischemia was performed for 30 min and reperfusion for 72 h. THC was injected intra-peritoneally (I.P.) once daily for a period of 3 days after 30 min of ischemia. The infarct area was measured using 2,3,5-triphenyltetrazolium chloride staining. Permeability was determined by brain edema and Evans Blue extravasation. The brain tissues were analyzed for oxidative stress, matrix metalloproteinase-9 (MMP-9), damage-regulated autophagy modulator (DRAM), and microtubule-associated protein 1 light chain 3 (LC3) by Western blot. The mRNA levels of S-adenosyl-L-homocysteine hydrolases (SAHH) and methylenetetrahydrofolate reductase (MTHFR) genes were measured by quantitative real-time polymerase chain reaction. Co-immunoprecipitation was used to determine the homocysteinylation of cyto-c. We found that brain edema and Evans Blue leakage were reduced in I/R + THC-treated groups as compared to sham-operated groups along with reduced brain infarct size. THC also decreased oxidative damage and ameliorated the homocysteinylation of cyto-c in-part by MMP-9 activation which leads to autophagy in I/R groups as compared to sham-operated groups. This study suggests a potential therapeutic role of dietary THC in cerebral ischemia.
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Jakubowski H, Głowacki R. Chemical biology of homocysteine thiolactone and related metabolites. Adv Clin Chem 2011; 55:81-103. [PMID: 22126025 DOI: 10.1016/b978-0-12-387042-1.00005-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Protein-related homocysteine (Hcy) metabolism produces Hcy-thiolactone, N-Hcy-protein, and N epsilon-homocysteinyl-lysine (N epsilon-Hcy-Lys). Hcy-thiolactone is generated in an error-editing reaction in protein biosynthesis when Hcy is erroneously selected in place of methionine by methionyl-tRNA synthetase. Hcy-thiolactone, an intramolecular thioester, is chemically reactive and forms isopeptide bonds with protein lysine residues in a process called N-homocysteinylation, which impairs or alters the protein's biological function. The resulting protein damage is exacerbated by a thiyl radical-mediated oxidation. N-Hcy-proteins undergo structural changes leading to aggregation and amyloid formation. These structural changes generate proteins, which are toxic and which induce an autoimmune response. Proteolytic degradation of N-Hcy-proteins generates N epsilon-Hcy-Lys. Levels of Hcy-thiolactone, N-Hcy-protein, and N epsilon-Hcy-Lys increase under pathological conditions in humans and mice and have been linked to cardiovascular and brain disorders. This chapter reviews fundamental biological chemistry of Hcy-thiolactone, N-Hcy-protein, and N epsilon-Hcy-Lys and discusses their clinical significance.
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Affiliation(s)
- Hieronim Jakubowski
- Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, International Center for Public Health, Newark, New Jersey, USA.
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27
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Jakubowski H. Quality control in tRNA charging. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 3:295-310. [PMID: 22095844 DOI: 10.1002/wrna.122] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Faithful translation of the genetic code during protein synthesis is fundamental to the growth, development, and function of living organisms. Aminoacyl-tRNA synthetases (AARSs), which define the genetic code by correctly pairing amino acids with their cognate tRNAs, are responsible for 'quality control' in the flow of information from a gene to a protein. When differences in binding energies of amino acids to an AARS are inadequate, editing is used to achieve high selectivity. Editing occurs at the synthetic active site by hydrolysis of noncognate aminoacyl-adenylates (pretransfer editing) and at a dedicated editing site located in a separate domain by deacylation of mischarged aminoacyl-tRNA (posttransfer editing). Access of nonprotein amino acids, such as homocysteine or ornithine, to the genetic code is prevented by the editing function of AARSs, which functionally partitions amino acids present in living cells into protein and nonprotein amino acids. Continuous editing is part of the tRNA aminoacylation process in living organisms from bacteria to human beings. Preventing mistranslation by the clearance of misactivated amino acids is crucial to cellular homeostasis and has a role in etiology of disease. Although there is a strong selective pressure to minimize mistranslation, some organisms possess error-prone AARSs that cause mistranslation. Elevated levels of mistranslation and the synthesis of statistical proteins can be beneficial for pathogens by increasing phenotypic variation essential for the evasion of host defenses.
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Affiliation(s)
- Hieronim Jakubowski
- Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, International Center for Public Health, Newark, NJ, USA.
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Jakubowski H. The role of paraoxonase 1 in the detoxification of homocysteine thiolactone. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 660:113-27. [PMID: 20221875 DOI: 10.1007/978-1-60761-350-3_11] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The thioester homocysteine (Hcy)-thiolactone, product of an error-editing reaction in protein biosynthesis, forms when Hcy is mistakenly selected by methionyl-tRNA synthetase. Accumulating evidence suggests that Hcy-thiolactone plays an important role in atherothrombosis. The thioester chemistry of Hcy-thiolactone underlies its ability to form isopeptide bonds with protein lysine residues, which impairs or alters protein function and has pathophysiological consequences including activation of an autoimmune response and enhanced thrombosis. Mammalian organisms, including human, have evolved the ability to eliminate Hcy-thiolactone. One such mechanism involves paraoxonase 1 (PON1), which has the ability to hydrolyze Hcy-thiolactone. This article outlines Hcy-thiolactone pathobiology and reviews evidence documenting the role of PON1 in minimizing Hcy-thiolactone and N-Hcy-protein accumulation.
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Affiliation(s)
- Hieronim Jakubowski
- Department of Biochemistry and Biotechnology, University of Life Sciences, Poznań, Poland.
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29
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Direct monitoring of albumin lysine-525 N-homocysteinylation in human serum by liquid chromatography/mass spectrometry. Anal Biochem 2010; 405:132-4. [DOI: 10.1016/j.ab.2010.04.034] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 04/27/2010] [Accepted: 04/28/2010] [Indexed: 11/22/2022]
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Aléssio ACM, Santos CXC, Debbas V, Oliveira LC, Haddad R, Annichino-Bizzacchi JM. Evaluation of mild hyperhomocysteinemia during the development of atherosclerosis in apolipoprotein E-deficient and normal mice. Exp Mol Pathol 2010; 90:45-50. [PMID: 20696152 DOI: 10.1016/j.yexmp.2010.07.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 07/29/2010] [Accepted: 07/29/2010] [Indexed: 11/16/2022]
Abstract
We focused on the effect of mild hyperhomocysteinemia (HHcy) on the development of atherosclerosis, using apolipoprotein E-deficient (apoE(-/-)) and normal mice. Mice received diets enriched in methionine with low or high levels of folate, B(12) and B(6) (diets B and C, respectively), and diet only with low levels of folate, B(12) and B(6) (diets D), to induce mild HHcy. Normal mice fed on diets B, C and D presented mild HHcy, but they did not develop atherosclerotic lesions after 24 weeks of diet. In addition, increased endoplasmic reticulum stress was present in normal mice fed on diet B, compared to others groups. ApoE(-/-) mice fed on diet B for 20 weeks presented the greatest atherosclerotic lesion area at the aortic sinus than other groups. These results suggest that the methionine may have a toxic effect on endothelium, and the B-vitamins addition on diet may have a protective effect in the long term, despite the increase on homocysteine levels. Mild HHcy accelerated the development of atherosclerosis in apoE(-/-) mice, and supplementation with B-vitamins is important for prevention of vascular disease, principally in the long term.
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Affiliation(s)
- Ana C M Aléssio
- Hematology-Hemotherapy Center, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil.
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Ishimine N, Usami Y, Nogi S, Sumida T, Kurihara Y, Matsuda K, Nakamura K, Yamauchi K, Okumura N, Tozuka M. Identification of N-homocysteinylated apolipoprotein AI in normal human serum. Ann Clin Biochem 2010; 47:453-9. [DOI: 10.1258/acb.2010.010035] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background In human serum, a portion of homocysteine (Hcy) exists as an N-linked form to the ε-amino group of protein lysine residues. N-homocysteinylated proteins differ structurally and functionally from native proteins. The present study strives to develop detection and potential semi-quantification methods for N-homocysteinylated apolipoprotein AI ( N-Hcy-apoAI) in human serum. Methods Serum treated with or without cysteamine was supplied to isoelectric focusing (IEF) followed by an immunoblot using an anti-apoAI antibody. Cysteamine treatment increased the isoelectric point for N-Hcy-apoAI, but not for unmodified apoAI, due to the presence of -SH group(s) derived from Hcy and the absence of a cysteine residue in the apoAI molecule. N-Hcy-apoAI was semi-quantified from the scanned immunoblot pattern via a computer. Results After cysteamine treatment, N-Hcy-apoAI in the serum was identified by IEF at the position with a higher pI value compared with intact apoAI. The reproducibility (between assays) of the semi-quantification method was 19.1% CV (coefficient of variation) for an average ratio 5.9% of N-Hcy-apoAI to the whole apoAI in the serum. Approximately 1.0–7.4% of apoAI was N-homocysteinylated in the serum obtained from 27 healthy subjects. Neither the ratio of N-Hcy-apoAI nor its concentration, calculated by total apoAI concentration, indicated correlation with the so-called total (free and S-linked) Hcy concentration. Conclusions We directly found that a portion of apoAI in the serum undergoes homocysteinylation in an N-linkage manner, and used this to develop a potential semi-quantification method for N-Hcy-apoAI.
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Affiliation(s)
- N Ishimine
- Analytical Laboratory Chemistry, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo
- Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto
| | - Y Usami
- Analytical Laboratory Chemistry, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo
| | - S Nogi
- Analytical Laboratory Chemistry, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo
| | - T Sumida
- Analytical Laboratory Chemistry, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo
| | - Y Kurihara
- Analytical Laboratory Chemistry, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo
| | - K Matsuda
- Department of Laboratory Medicine, Shinshu University Hospital, Matsumoto
| | - K Nakamura
- Department of Clinical Laboratory, The University of Tokyo Hospital, Tokyo
| | - K Yamauchi
- Clinical Pathology, Graduate School of Comprehensive Human Sciences, Tsukuba University, Tsukuba
| | - N Okumura
- Department of Biomedical Laboratory Sciences, School of Health Sciences, Shinshu University, Matsumoto, Japan
| | - M Tozuka
- Analytical Laboratory Chemistry, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo
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Homocysteine and Hypertension in Diabetes: Does PPARgamma Have a Regulatory Role? PPAR Res 2010; 2010:806538. [PMID: 20613990 PMCID: PMC2895301 DOI: 10.1155/2010/806538] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Revised: 11/11/2009] [Accepted: 05/10/2010] [Indexed: 12/31/2022] Open
Abstract
Dysfunction of macro- and microvessels is a major cause of morbidity and mortality in patients with cardio-renovascular diseases such as atherosclerosis, hypertension, and diabetes. Renal failure and impairment of renal function due to vasoconstriction of the glomerular arteriole in diabetic nephropathy leads to renal volume retention and increase in plasma homocysteine level. Homocysteine, which is a nonprotein amino acid, at elevated levels is an independent cardio-renovascular risk factor. Homocysteine induces oxidative injury of vascular endothelial cells, involved in matrix remodeling through modulation of the matrix metalloproteinase (MMP)/tissue inhibitor of metalloproteinase (TIMP) axis, and increased formation and accumulation of extracellular matrix protein, such as collagen. In heart this leads to increased endothelial-myocyte uncoupling resulting in diastolic dysfunction and hypertension. In the kidney, increased matrix accumulation in the glomerulus causes glomerulosclerosis resulting in hypofiltration, increased renal volume retention, and hypertension. PPARγ agonist reduces tissue homocysteine levels and is reported to ameliorate homocysteine-induced deleterious vascular effects in diabetes. This review, in light of current information, focuses on the beneficial effects of PPARγ agonist in homocysteine-associated hypertension and vascular remodeling in diabetes.
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Identification and origin of Nε-homocysteinyl-lysine isopeptide in humans and mice. Amino Acids 2010; 39:1563-9. [DOI: 10.1007/s00726-010-0627-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/08/2010] [Indexed: 10/19/2022]
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Głowacki R, Bald E, Jakubowski H. An on-column derivatization method for the determination of homocysteine-thiolactone and protein N-linked homocysteine. Amino Acids 2010; 41:187-94. [DOI: 10.1007/s00726-010-0521-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Accepted: 02/09/2010] [Indexed: 11/30/2022]
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Zang T, Dai S, Chen D, Lee BWK, Liu S, Karger BL, Zhou ZS. Chemical methods for the detection of protein N-homocysteinylation via selective reactions with aldehydes. Anal Chem 2009; 81:9065-71. [PMID: 19874060 PMCID: PMC2771319 DOI: 10.1021/ac9017132] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Elevated blood levels of homocysteine (Hcy), hyperhomocysteinemia or homocystinuria, have been associated with various diseases and conditions. Homocysteine thiolactone (Hcy TL) is a metabolite of Hcy and reacts with amine groups in proteins to form stable amides, homocystamides, or N-homocysteinylated proteins. It has been proposed that protein N-homocysteinylation contributes to the cytotoxicity of elevated Hcy. Due to its heterogeneity and relatively low abundance, detection of this posttranslational modification remains challenging. On the other hand, the gamma-aminothiol group in homocystamides imparts different chemical reactivities than the native proteins. Under mildly acidic conditions, gamma-aminothiols irreversibly and stoichiometrically react with aldehydes to form stable 1,3-thiazines, whereas the reversible Schiff base formation between aldehydes and amino groups in native proteins is markedly disfavored due to protonation of amines. As such, we have developed highly selective chemical methods to derivatize N-homocysteinylated proteins with various aldehyde tags, thereby facilitating the subsequent analyses. For instance, fluorescent or biotin tagging coupled with gel electrophoresis permits quantification and global profiling of complex biological samples, such as hemoglobin and plasma from rat, mouse and human; affinity enrichment with aldehyde resins drastically reduces sample complexity. In addition, different reactivities of lysine residues in hemoglobin toward Hcy TL were observed.
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Affiliation(s)
- Tianzhu Zang
- Barnett Institute of Chemical and Biological Analysis and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Shujia Dai
- Barnett Institute of Chemical and Biological Analysis and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Dajun Chen
- Barnett Institute of Chemical and Biological Analysis and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Bobby W. K. Lee
- Barnett Institute of Chemical and Biological Analysis and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Suli Liu
- Barnett Institute of Chemical and Biological Analysis and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Barry L. Karger
- Barnett Institute of Chemical and Biological Analysis and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Zhaohui Sunny Zhou
- Barnett Institute of Chemical and Biological Analysis and Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
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Perla‐Kaján J, Jakubowski H. Paraoxonase 1 protects against protein
N
‐homocysteinylation in humans. FASEB J 2009; 24:931-6. [DOI: 10.1096/fj.09-144410] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Joanna Perla‐Kaján
- Department of Microbiology and Molecular GeneticsUniversity of Medicine and Dentistry New Jersey‐New Jersey Medical SchoolInternational Center for Public HealthNewarkNew JerseyUSA
- Department of Biochemistry and BiotechnologyUniversity of Life SciencesPoznanPoland
| | - Hieronim Jakubowski
- Department of Microbiology and Molecular GeneticsUniversity of Medicine and Dentistry New Jersey‐New Jersey Medical SchoolInternational Center for Public HealthNewarkNew JerseyUSA
- Department of Biochemistry and BiotechnologyUniversity of Life SciencesPoznanPoland
- Institute of Bioorganic ChemistryPoznanPoland
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Jakubowski H, Perla-Kaján J, Finnell RH, Cabrera RM, Wang H, Gupta S, Kruger WD, Kraus JP, Shih DM. Genetic or nutritional disorders in homocysteine or folate metabolism increase protein N-homocysteinylation in mice. FASEB J 2009; 23:1721-7. [PMID: 19204075 DOI: 10.1096/fj.08-127548] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Genetic disorders of homocysteine (Hcy) or folate metabolism or high-methionine diets elevate plasma Hcy and its atherogenic metabolite Hcy-thiolactone. In humans, severe hyperhomocysteinemia due to genetic alterations in cystathionine beta-synthase (Cbs) or methylenetetrahydrofolate reductase (Mthfr) results in neurological abnormalities and premature death from vascular complications. In mouse models, dietary or genetic hyperhomocysteinemia results in liver or brain pathological changes and accelerates atherosclerosis. Hcy-thiolactone has the ability to form isopeptide bonds with protein lysine residues, which generates modified proteins (N-Hcy-protein) with autoimmunogenic and prothrombotic properties. Our aim was to determine how N-Hcy-protein levels are affected by genetic or nutritional disorders in Hcy or folate metabolism in mice. We found that plasma N-Hcy-protein was elevated 10-fold in mice fed a high-methionine diet compared with the animals fed a normal commercial diet. We also found that inactivation of Cbs, Mthfr, or the proton-coupled folate transporter (Pcft) gene resulted in a 10- to 30-fold increase in plasma or serum N-Hcy-protein levels. Liver N-Hcy-protein was elevated 3.4-fold in severely and 11-fold in extremely hyperhomocysteinemic Cbs-deficient mice, 3.6-fold in severely hyperhomocysteinemic Pcft mice, but was not elevated in mildly hyperhomocysteinemic Mthfr-deficient animals, suggesting that mice have a capacity to prevent accumulation of N-Hcy-protein in their organs. These findings provide evidence that N-Hcy-protein is an important metabolite associated with Hcy pathophysiology in the mouse.
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Affiliation(s)
- Hieronim Jakubowski
- Department of Microbiology and Molecular Genetics, UMDNJ-New Jersey Medical School, International Center for Public Health, 225 Warren St., Newark, NJ 07101-1709, USA.
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Jakubowski H, Boers GHJ, Strauss KA. Mutations in cystathionine beta-synthase or methylenetetrahydrofolate reductase gene increase N-homocysteinylated protein levels in humans. FASEB J 2008; 22:4071-6. [PMID: 18708589 DOI: 10.1096/fj.08-112086] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Severely elevated plasma homocysteine (Hcy) levels observed in genetic disorders of Hcy metabolism are associated with pathologies in multiple organs and lead to premature death due to vascular complications. In addition to elevating plasma Hcy, mutations in cystathionine beta-synthase (CBS) or methylenetetrahydrofolate reductase (MTHFR) gene lead to markedly elevated levels of circulating Hcy-thiolactone. The thiooester chemistry of Hcy-thiolactone underlies its ability to form isopeptide bonds with protein lysine residues (N-Hcy-protein), which may impair or alter the protein's function. However, it was not known whether genetic deficiencies in Hcy metabolism affect N-Hcy-protein levels in humans. Here we show that plasma N-Hcy-protein levels are significantly elevated in CBS- and MTHFR-deficient patients. We also show that CBS-deficient patients have significantly elevated plasma levels of prothrombotic N-Hcy-fibrinogen. These results provide a possible explanation for increased atherothrombosis observed in CBS-deficient patients.
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Affiliation(s)
- Hieronim Jakubowski
- Department of Microbiology & Molecular Genetics, UMDNJ-New Jersey Medical School, International Center for Public Health, 225 Warren St., Newark, NJ 07101-1709, USA.
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