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Ban XX, Wan H, Wan XX, Tan YT, Hu XM, Ban HX, Chen XY, Huang K, Zhang Q, Xiong K. Copper Metabolism and Cuproptosis: Molecular Mechanisms and Therapeutic Perspectives in Neurodegenerative Diseases. Curr Med Sci 2024; 44:28-50. [PMID: 38336987 DOI: 10.1007/s11596-024-2832-z] [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] [Received: 11/24/2023] [Accepted: 12/17/2023] [Indexed: 02/12/2024]
Abstract
Copper is an essential trace element, and plays a vital role in numerous physiological processes within the human body. During normal metabolism, the human body maintains copper homeostasis. Copper deficiency or excess can adversely affect cellular function. Therefore, copper homeostasis is stringently regulated. Recent studies suggest that copper can trigger a specific form of cell death, namely, cuproptosis, which is triggered by excessive levels of intracellular copper. Cuproptosis induces the aggregation of mitochondrial lipoylated proteins, and the loss of iron-sulfur cluster proteins. In neurodegenerative diseases, the pathogenesis and progression of neurological disorders are linked to copper homeostasis. This review summarizes the advances in copper homeostasis and cuproptosis in the nervous system and neurodegenerative diseases. This offers research perspectives that provide new insights into the targeted treatment of neurodegenerative diseases based on cuproptosis.
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Affiliation(s)
- Xiao-Xia Ban
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, 430013, China
| | - Hao Wan
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, 430013, China
| | - Xin-Xing Wan
- Department of Endocrinology, Third Xiangya Hospital, Central South University, Changsha, 430013, China
| | - Ya-Ting Tan
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, 430013, China
| | - Xi-Min Hu
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, 430013, China
| | - Hong-Xia Ban
- Affiliated Hospital, Inner Mongolia Medical University, Hohhot, 010050, China
| | - Xin-Yu Chen
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, 430013, China
| | - Kun Huang
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, 430013, China
| | - Qi Zhang
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, 430013, China.
- Key Laboratory of Emergency and Trauma of Ministry of Education, Hainan Medical University, Haikou, 571199, China.
| | - Kun Xiong
- Department of Human Anatomy and Neurobiology, School of Basic Medical Science, Central South University, Changsha, 430013, China.
- Key Laboratory of Emergency and Trauma of Ministry of Education, Hainan Medical University, Haikou, 571199, China.
- Hunan Key Laboratory of Ophthalmology, Changsha, 430013, China.
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Akakpo JY, Ramachandran A, Rumack BH, Wallace DP, Jaeschke H. Lack of mitochondrial Cyp2E1 drives acetaminophen-induced ER stress-mediated apoptosis in mouse and human kidneys: Inhibition by 4-methylpyrazole but not N-acetylcysteine. Toxicology 2023; 500:153692. [PMID: 38042273 PMCID: PMC11097675 DOI: 10.1016/j.tox.2023.153692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 11/20/2023] [Accepted: 11/28/2023] [Indexed: 12/04/2023]
Abstract
Acetaminophen (APAP) overdose causes liver injury and acute liver failure, as well as acute kidney injury, which is not prevented by the clinical antidote N-acetyl-L-cysteine (NAC). The absence of therapeutics targeting APAP-induced nephrotoxicity is due to gaps in understanding the mechanisms of renal injury. APAP metabolism through Cyp2E1 drives cell death in both the liver and kidney. We demonstrate that Cyp2E1 is localized to the proximal tubular cells in mouse and human kidneys. Virtually all the Cyp2E1 in kidney cells is in the endoplasmic reticulum (ER), not in mitochondria. By contrast, hepatic Cyp2E1 is in both the ER and mitochondria of hepatocytes. Consistent with this subcellular localization, a dose of 600 mg/kg APAP in fasted C57BL/6J mice induced the formation of APAP protein adducts predominantly in mitochondria of hepatocytes, but the ER of the proximal tubular cells of the kidney. We found that reactive metabolite formation triggered ER stress-mediated activation of caspase-12 and apoptotic cell death in the kidney. While co-treatment with 4-methylpyrazole (4MP; fomepizole) or the caspase inhibitor Ac-DEVD-CHO prevented APAP-induced cleavage of procaspase-12 and apoptosis in the kidney, treatment with NAC had no effect. These mechanisms are clinically relevant because 4MP but not NAC also significantly attenuated APAP-induced apoptotic cell death in primary human kidney cells. We conclude that reactive metabolite formation by Cyp2E1 in the ER results in sustained ER stress that causes activation of procaspase-12, triggering apoptosis of proximal tubular cells, and that 4MP but not NAC may be an effective antidote against APAP-induced kidney injury.
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Affiliation(s)
- Jephte Y Akakpo
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Anup Ramachandran
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Barry H Rumack
- Department of Emergency Medicine and Pediatrics, University of Colorado School of Medicine, Denver, CO, USA
| | - Darren P Wallace
- Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, KS, USA
| | - Hartmut Jaeschke
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA.
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3
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Clark RSB, Empey PE, Kochanek PM, Bell MJ. N-Acetylcysteine and Probenecid Adjuvant Therapy for Traumatic Brain Injury. Neurotherapeutics 2023; 20:1529-1537. [PMID: 37596428 PMCID: PMC10684451 DOI: 10.1007/s13311-023-01422-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2023] [Indexed: 08/20/2023] Open
Abstract
N-Acetylcysteine (NAC) has shown promise as a putative neurotherapeutic for traumatic brain injury (TBI). Yet, many such promising compounds have limited ability to cross the blood-brain barrier (BBB), achieve therapeutic concentrations in brain, demonstrate target engagement, among other things, that have hampered successful translation. A pharmacologic strategy for overcoming poor BBB permeability and/or efflux out of the brain of organic acid-based, small molecule therapeutics such as NAC is co-administration with a targeted or nonselective membrane transporter inhibitor. Probenecid is a classic ATP-binding cassette and solute carrier inhibitor that blocks transport of organic acids, including NAC. Accordingly, combination therapy using probenecid as an adjuvant with NAC represents a logical neurotherapeutic strategy for treatment of TBI (and other CNS diseases). We have completed a proof-of-concept pilot study using this drug combination in children with severe TBI-the Pro-NAC Trial (ClinicalTrials.gov NCT01322009). In this review, we will discuss the background and rationale for combination therapy with probenecid and NAC in TBI, providing justification for further clinical investigation.
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Affiliation(s)
- Robert S B Clark
- Departments of Critical Care Medicine and Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, USA.
- UPMC Children's Hospital of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.
| | - Philip E Empey
- Department of Pharmacy & Therapeutics, Center for Clinical Pharmaceutical Sciences, University of Pittsburgh School of Pharmacy, Pittsburgh, PA, USA
| | - Patrick M Kochanek
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, USA
- UPMC Children's Hospital of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
- Departments of Critical Care Medicine, Anesthesiology, and Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Michael J Bell
- Division of Critical Care Medicine, Department of Pediatrics, Children's National Medical Center, Washington, DC, USA
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Caridade-Silva R, Araújo B, Martins-Macedo J, Teixeira FG. N-Acetylcysteine Treatment May Compensate Motor Impairments through Dopaminergic Transmission Modulation in a Striatal 6-Hydroxydopamine Parkinson's Disease Rat Model. Antioxidants (Basel) 2023; 12:1257. [PMID: 37371987 DOI: 10.3390/antiox12061257] [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: 04/05/2023] [Revised: 05/29/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
Preventing degeneration and the loss of dopaminergic neurons (DAn) in the brain while mitigating motor symptoms remains a challenge in Parkinson's Disease (PD) treatment development. In light of this, developing or repositioning potential disease-modifying approaches is imperative to achieve meaningful translational gains in PD research. Under this concept, N-acetylcysteine (NAC) has revealed promising perspectives in preserving the dopaminergic system capability and modulating PD mechanisms. Although NAC has been shown to act as an antioxidant and (neuro)protector of the brain, it has yet to be acknowledged how this repurposed drug can improve motor symptomatology and provide disease-modifying properties in PD. Therefore, in the present work, we assessed the impact of NAC on motor and histological deficits in a striatal 6-hydroxydopamine (6-OHDA) rat model of PD. The results revealed that NAC enhanced DAn viability, as we found that it could restore dopamine transporter (DAT) levels compared to the untreated 6-OHDA group. Such findings were positively correlated with a significant amelioration in the motor outcomes of the 6-OHDA-treated animals, demonstrating that NAC may, somehow, be a modulator of PD degenerative mechanisms. Overall, we postulated a proof-of-concept milestone concerning the therapeutic application of NAC. Nevertheless, it is extremely important to understand the complexity of this drug and how its therapeutical properties interact with the cellular and molecular PD mechanisms.
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Affiliation(s)
- Rita Caridade-Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, 4710-057/4805-017 Braga/Guimarães, Portugal
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- Center for Translational Health and Medical Biotechnology Research, School of Health, Polytechnic University of Porto, 4200-465 Porto, Portugal
| | - Bruna Araújo
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, 4710-057/4805-017 Braga/Guimarães, Portugal
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- Center for Translational Health and Medical Biotechnology Research, School of Health, Polytechnic University of Porto, 4200-465 Porto, Portugal
| | - Joana Martins-Macedo
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- Center for Translational Health and Medical Biotechnology Research, School of Health, Polytechnic University of Porto, 4200-465 Porto, Portugal
| | - Fábio G Teixeira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, 4710-057/4805-017 Braga/Guimarães, Portugal
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- Center for Translational Health and Medical Biotechnology Research, School of Health, Polytechnic University of Porto, 4200-465 Porto, Portugal
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Lai HY, Setyawati MI, Duarte CV, Chua HM, Low CT, Ng KW. Human hair proteins as natural reactive oxygen species scavengers for in vitro applications. J Biomed Mater Res B Appl Biomater 2023; 111:933-945. [PMID: 36418224 DOI: 10.1002/jbm.b.35203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 11/09/2022] [Accepted: 11/13/2022] [Indexed: 11/25/2022]
Abstract
Human hair proteins are recognized for their intrinsically high cysteine content. They can be solubilized while preserving their highly reductive thiol groups for free radical scavenging applications. The presence of aromatic and nucleophilic amino acids such as methionine, serine, phenylalanine, and threonine further contribute to the antioxidative potential of this material. Herein, utilizing the DPPH (2,2-diphenyl-1-picrylhydrazyl) and acellular 2',7'-dichlorodihydrofluorescein diacetate (H2 DCFDA) assays, keratins are demonstrated to possess the highest radical scavenging activity among the studied hair proteins. Consequently, protection against hydrogen peroxide-induced oxidative stress in human dermal fibroblasts (HDFs) cultured in human hair keratin supplemented media is demonstrated. Quenching of reactive oxygen species in the HDF is observed using the CellROX Green dye and the expression levels of antioxidant (HMOX1, SOD2, GPX1) and tumor suppressor (TP53) genes is analyzed using qPCR. Collectively, this study presents further evidence and demonstrates the in vitro application potential of hair proteins, especially keratins, as an antioxidizing supplement.
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Affiliation(s)
- Hui Ying Lai
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore.,Nanyang Environment & Water Research Institute (Environmental Chemistry and Materials Centre), Interdisciplinary Graduate Program, Nanyang Technological University, Singapore, Singapore
| | | | - Catarina Vizetto Duarte
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Huei Min Chua
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Choon Teck Low
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Kee Woei Ng
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore.,Nanyang Environment & Water Research Institute (Environmental Chemistry and Materials Centre), Interdisciplinary Graduate Program, Nanyang Technological University, Singapore, Singapore.,Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
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6
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Kalyanaraman B. NAC, NAC, Knockin' on Heaven's door: Interpreting the mechanism of action of N-acetylcysteine in tumor and immune cells. Redox Biol 2022; 57:102497. [PMID: 36242913 PMCID: PMC9563555 DOI: 10.1016/j.redox.2022.102497] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 10/05/2022] [Indexed: 11/17/2022] Open
Abstract
N-acetylcysteine (NAC) has been used as a direct scavenger of reactive oxygen species (hydrogen peroxide, in particular) and an antioxidant in cancer biology and immuno-oncology. NAC is the antioxidant drug most frequently employed in studies using tumor cells, immune cells, and preclinical mouse xenografts. Most studies use redox-active fluorescent probes such as dichlorodihydrofluorescein, hydroethidine, mitochondria-targeted hydroethidine, and proprietary kit-based probes (i.e., CellROX Green and CellROX Red) for intracellular detection of superoxide or hydrogen peroxide. Inhibition of fluorescence by NAC was used as a key experimental observation to support the formation of reactive oxygen species and redox mechanisms proposed for ferroptosis, tumor metastasis, and redox signaling in the tumor microenvironment. Reactive oxygen species such as superoxide and hydrogen peroxide stimulate or abrogate tumor cells and immune cells depending on multiple factors. Understanding the mechanism of antioxidants is crucial for interpretation of the results. Because neither NAC nor the fluorescent probes indicated above react directly with hydrogen peroxide, it is critically important to reinterpret the results to advance our understanding of the mechanism of action of NAC and shed additional mechanistic insight on redox-regulated signaling in tumor biology. To this end, this review is focused on how NAC could affect multiple pathways in cancer cells, including iron signaling, ferroptosis, and the glutathione-dependent antioxidant and redox signaling mechanism, and how NAC could inhibit oxidation of the fluorescent probes through multiple mechanisms.
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Affiliation(s)
- Balaraman Kalyanaraman
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, USA.
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Ho T, Ahmadi S, Kerman K. Do glutathione and copper interact to modify Alzheimer's disease pathogenesis? Free Radic Biol Med 2022; 181:180-196. [PMID: 35092854 DOI: 10.1016/j.freeradbiomed.2022.01.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 01/20/2022] [Accepted: 01/24/2022] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder first described in 1906 that is currently estimated to impact ∼40 million people worldwide. Extensive research activities have led to a wealth of information on the pathogenesis, hallmarks, and risk factors of AD; however, therapeutic options remain extremely limited. The large number of pathogenic factors that have been reported to potentially contribute to AD include copper dyshomeostasis as well as increased oxidative stress, which is related to alterations to molecular antioxidants like glutathione (GSH). While the individual roles of GSH and copper in AD have been studied by many research groups, their interactions have received relatively little attention, although they appear to interact and affect each other's regulation. Existing knowledge on how GSH-copper interactions may affect AD is sparse and lacks focus. This review first highlights the most relevant individual roles that GSH and copper play in physiology and AD, and then collects and assesses research concerning their interactions, in an effort to provide a more accessible and understandable picture of the role of GSH, copper, and their interactions in AD.
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Affiliation(s)
- Talia Ho
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada; Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
| | - Soha Ahmadi
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada.
| | - Kagan Kerman
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada; Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada.
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8
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Shaikh DS, Parmar S, Kalia D. Michael addition–elimination–cyclization based turn-on fluorescence (MADELCY TOF) probes for cellular cysteine imaging and estimation of blood serum cysteine and aminoacylase-1. Analyst 2022; 147:3876-3884. [DOI: 10.1039/d2an00713d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Michael addition–elimination–cyclization based turn-on fluorescence (MADELCY TOF) probes for the highly sensitive estimation of Cys and aminoacylase-1 (ACY-1).
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Affiliation(s)
- Dastgir Shakil Shaikh
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhauri, Bhopal Bypass Road, Bhopal, 462066, India
| | - Sangeeta Parmar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhauri, Bhopal Bypass Road, Bhopal, 462066, India
| | - Dimpy Kalia
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Bhopal, Bhauri, Bhopal Bypass Road, Bhopal, 462066, India
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9
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Vobruba S, Kamenik Z, Kadlcik S, Janata J. N-Deacetylation in Lincosamide Biosynthesis Is Catalyzed by a TldD/PmbA Family Protein. ACS Chem Biol 2020; 15:2048-2054. [PMID: 32786288 DOI: 10.1021/acschembio.0c00224] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lincosamides are clinically important antibiotics originally produced as microbial specialized metabolites. The complex biosynthesis of lincosamides is coupled to the metabolism of mycothiol as a sulfur donor. Here, we elucidated the N-deacetylation of the mycothiol-derived N-acetyl-l-cysteine residue of a lincosamide intermediate, which is comprised of an amino acid and an aminooctose connected via an amide bond. We purified this intermediate from the culture broth of a deletion mutant strain and tested it as a substrate of recombinant lincosamide biosynthetic proteins in the in vitro assays that were monitored via liquid chromatography-mass spectrometry. Our findings showed that the N-deacetylation reaction is catalyzed by CcbIH/CcbQ or LmbIH/LmbQ proteins in celesticetin and lincomycin biosynthesis, respectively. These are the first N-deacetylases from the TldD/PmbA protein family, from which otherwise only several proteases and peptidases were functionally characterized. Furthermore, we present a sequence similarity network of TldD/PmbA proteins, which suggests that the lincosamide N-deacetylases are unique among these widely distributed proteins.
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Affiliation(s)
- Simon Vobruba
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Zdenek Kamenik
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Stanislav Kadlcik
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Jiri Janata
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
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Abstract
The mercapturic acid pathway is a major route for the biotransformation of xenobiotic and endobiotic electrophilic compounds and their metabolites. Mercapturic acids (N-acetyl-l-cysteine S-conjugates) are formed by the sequential action of the glutathione transferases, γ-glutamyltransferases, dipeptidases, and cysteine S-conjugate N-acetyltransferase to yield glutathione S-conjugates, l-cysteinylglycine S-conjugates, l-cysteine S-conjugates, and mercapturic acids; these metabolites constitute a "mercapturomic" profile. Aminoacylases catalyze the hydrolysis of mercapturic acids to form cysteine S-conjugates. Several renal transport systems facilitate the urinary elimination of mercapturic acids; urinary mercapturic acids may serve as biomarkers for exposure to chemicals. Although mercapturic acid formation and elimination is a detoxication reaction, l-cysteine S-conjugates may undergo bioactivation by cysteine S-conjugate β-lyase. Moreover, some l-cysteine S-conjugates, particularly l-cysteinyl-leukotrienes, exert significant pathophysiological effects. Finally, some enzymes of the mercapturic acid pathway are described as the so-called "moonlighting proteins," catalytic proteins that exert multiple biochemical or biophysical functions apart from catalysis.
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Affiliation(s)
- Patrick E Hanna
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - M W Anders
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
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11
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Therapeutic potential of N-acetylcysteine in acrylamide acute neurotoxicity in adult zebrafish. Sci Rep 2019; 9:16467. [PMID: 31712630 PMCID: PMC6848153 DOI: 10.1038/s41598-019-53154-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/28/2019] [Indexed: 02/07/2023] Open
Abstract
Two essential key events in acrylamide (ACR) acute neurotoxicity are the formation of adducts with nucleophilic sulfhydryl groups on cysteine residues of selected proteins in the synaptic terminals and the depletion of the glutathione (GSx) stores in neural tissue. The use of N-acetylcysteine (NAC) has been recently proposed as a potential antidote against ACR neurotoxicity, as this chemical is not only a well-known precursor of the reduced form of glutathione (GSH), but also is an scavenger of soft electrophiles such as ACR. In this study, the suitability of 0.3 and 0.75 mM NAC to protect against the neurotoxic effect of 0.75 mM ACR has been tested in vivo in adult zebrafish. NAC provided only a mild to negligible protection against the changes induced by ACR in the motor function, behavior, transcriptome and proteome. The permeability of NAC to cross blood-brain barrier (BBB) was assessed, as well as the ACR-scavenging activity and the gamma-glutamyl-cysteine ligase (γ-GCL) and acylase I activities. The results show that ACR not only depletes GSx levels but also inhibits it synthesis from NAC/cysteine, having a dramatic effect over the glutathione system. Moreover, results indicate a very low NAC uptake to the brain, probably by a combination of low BBB permeability and high deacylation of NAC during the intestinal absorption. These results strongly suggest that the use of NAC is not indicated in ACR acute neurotoxicity treatment.
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12
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Zuhra K, Tomé CS, Masi L, Giardina G, Paulini G, Malagrinò F, Forte E, Vicente JB, Giuffrè A. N-Acetylcysteine Serves as Substrate of 3-Mercaptopyruvate Sulfurtransferase and Stimulates Sulfide Metabolism in Colon Cancer Cells. Cells 2019; 8:cells8080828. [PMID: 31382676 PMCID: PMC6721681 DOI: 10.3390/cells8080828] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 07/31/2019] [Accepted: 08/02/2019] [Indexed: 12/12/2022] Open
Abstract
Hydrogen sulfide (H2S) is an endogenously produced signaling molecule. The enzymes 3-mercaptopyruvate sulfurtransferase (MST), partly localized in mitochondria, and the inner mitochondrial membrane-associated sulfide:quinone oxidoreductase (SQR), besides being respectively involved in the synthesis and catabolism of H2S, generate sulfane sulfur species such as persulfides and polysulfides, currently recognized as mediating some of the H2S biological effects. Reprogramming of H2S metabolism was reported to support cellular proliferation and energy metabolism in cancer cells. As oxidative stress is a cancer hallmark and N-acetylcysteine (NAC) was recently suggested to act as an antioxidant by increasing intracellular levels of sulfane sulfur species, here we evaluated the effect of prolonged exposure to NAC on the H2S metabolism of SW480 colon cancer cells. Cells exposed to NAC for 24 h displayed increased expression and activity of MST and SQR. Furthermore, NAC was shown to: (i) persist at detectable levels inside the cells exposed to the drug for up to 24 h and (ii) sustain H2S synthesis by human MST more effectively than cysteine, as shown working on the isolated recombinant enzyme. We conclude that prolonged exposure of colon cancer cells to NAC stimulates H2S metabolism and that NAC can serve as a substrate for human MST.
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Affiliation(s)
- Karim Zuhra
- Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, I-00185 Rome, Italy
- CNR Institute of Molecular Biology and Pathology, Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Catarina S Tomé
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB NOVA), Avenida da República (EAN), 2780-157 Oeiras, Portugal
| | - Letizia Masi
- Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Giorgio Giardina
- Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Giulia Paulini
- Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Francesca Malagrinò
- Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Elena Forte
- Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro 5, I-00185 Rome, Italy.
| | - João B Vicente
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB NOVA), Avenida da República (EAN), 2780-157 Oeiras, Portugal.
| | - Alessandro Giuffrè
- CNR Institute of Molecular Biology and Pathology, Piazzale Aldo Moro 5, I-00185 Rome, Italy.
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Balamurugan TST, Huang CH, Chang PC, Huang ST. Electrochemical Molecular Switch for the Selective Profiling of Cysteine in Live Cells and Whole Blood and for the Quantification of Aminoacylase-1. Anal Chem 2018; 90:12631-12638. [PMID: 30350617 DOI: 10.1021/acs.analchem.8b02799] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A first-of-a-kind latent electrochemical redox probe, ferrocene carbamate phenyl acrylate (FCPA), was developed for the selective detection of cysteine (Cys) and aminoacylase (ACY-1). The electrochemical signal generated by this probe was shown to be highly specific to Cys and insensitive to other amino acids and biological redox reactants. The FCPA-incorporated electrochemical sensor exhibited a broad dynamic range of 0.25-100 μM toward Cys. This probe also proficiently monitored the ACY-1-catalyzed biochemical transformation of N-acetylcysteine (NAC) into Cys, and this proficiency was used to develop an electrochemical assay for quantifying active ACY-1, which it did so in a dynamic range of 10-200 pM (0.1-2 mU/cm3) with a detection limit of 1 pM (0.01 mU/cm3). Furthermore, the probe was utilized in real-time tracking and quantification of cellular Cys production, specifically in Escherichia coli W3110, along with a whole blood assay to determine levels of Cys and spiked ACY-1 in blood with a reliable analytical performance.
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Affiliation(s)
- T S T Balamurugan
- Department of Chemical Engineering and Biotechnology , National Taipei University of Technology , Taipei 106 , Taiwan.,Institute of Biochemical and Biomedical Engineering , National Taipei University of Technology , Taipei 106 , Taiwan
| | - Chih-Hung Huang
- Department of Chemical Engineering and Biotechnology , National Taipei University of Technology , Taipei 106 , Taiwan.,Institute of Biochemical and Biomedical Engineering , National Taipei University of Technology , Taipei 106 , Taiwan
| | - Pu-Chieh Chang
- Department of Chemical Engineering and Biotechnology , National Taipei University of Technology , Taipei 106 , Taiwan.,Institute of Biochemical and Biomedical Engineering , National Taipei University of Technology , Taipei 106 , Taiwan
| | - Sheng-Tung Huang
- Department of Chemical Engineering and Biotechnology , National Taipei University of Technology , Taipei 106 , Taiwan.,Institute of Biochemical and Biomedical Engineering , National Taipei University of Technology , Taipei 106 , Taiwan
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14
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Satoh K. Strong carcinogenic stress response induction of preneoplastic cells positive for GST-P in the rat liver: Physiological mechanism for initiation. Life Sci 2018; 200:42-48. [PMID: 29501922 DOI: 10.1016/j.lfs.2018.02.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 02/13/2018] [Accepted: 02/27/2018] [Indexed: 02/06/2023]
Abstract
AIMS To identify experimental conditions that induce preneoplastic cells positive for glutathione S-transferase P-form (GST-P) in the rat liver by new approaches, and analysis of the mechanism of cancer initiation based on the findings. MAIN METHODS The experimental protocols employed to induce GST-P+ preneoplastic cells in rat liver were as follows. Protocol 1: adult rats were fed basal diet containing 2-acetylaminofluorene (AAF, 0.02% by wt) and high concentrations of N-acetyl-l-cysteine (0.5%) over 10 weeks. Protocol 2: rats were subjected to partial hepatectomy (2/3PH), followed by an AAF (0.04%) diet for two more weeks. Vibratome-prepared liver sections were then immunostained for GST-P. KEY FINDINGS GST-P was inducible in the rat liver in response to the strong carcinogenic stress by AAF in the two experimental protocols. When examined immunocytochemically with vibratome sections, the biliary tracts of hepatocytes, GST-P+ single hepatocytes and foci were heavily positive for the marker enzyme in addition to ordinary cytosolic staining of preneoplastic cell populations. The biliary tracts of hepatocytes were severely injured, and the excretory portions of GST-P+ single hepatocytes were significantly injured. SIGNIFICANCE The cytotoxic action of AAF that give rise to the GST-P+ single hepatocytes was suggested to be an injury to the excretory pump(s) and the duct of hepatocytes. A new physiological mechanism was hypothesized for the induction of preneoplastic cell populations in the rat liver instead of a genetic mechanism.
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Affiliation(s)
- Kimihiko Satoh
- Department of Biomedical Sciences, Hirosaki University, Graduate School of Health Sciences, Hon-Cho 66-1, Hirosaki 036-8564, Japan.
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15
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N-Acetyl Cysteine Functions as a Fast-Acting Antioxidant by Triggering Intracellular H 2S and Sulfane Sulfur Production. Cell Chem Biol 2018; 25:447-459.e4. [PMID: 29429900 DOI: 10.1016/j.chembiol.2018.01.011] [Citation(s) in RCA: 237] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 12/04/2017] [Accepted: 01/11/2018] [Indexed: 12/11/2022]
Abstract
The cysteine prodrug N-acetyl cysteine (NAC) is widely used as a pharmacological antioxidant and cytoprotectant. It has been reported to lower endogenous oxidant levels and to protect cells against a wide range of pro-oxidative insults. As NAC itself is a poor scavenger of oxidants, the molecular mechanisms behind the antioxidative effects of NAC have remained uncertain. Here we show that NAC-derived cysteine is desulfurated to generate hydrogen sulfide, which in turn is oxidized to sulfane sulfur species, predominantly within mitochondria. We provide evidence suggesting the possibility that sulfane sulfur species produced by 3-mercaptopyruvate sulfurtransferase and sulfide:quinone oxidoreductase are the actual mediators of the immediate antioxidative and cytoprotective effects provided by NAC.
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16
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Abstract
Many potentially toxic electrophilic xenobiotics and some endogenous compounds are detoxified by conversion to the corresponding glutathione S-conjugate, which is metabolized to the N-acetylcysteine S-conjugate (mercapturate) and excreted. Some mercapturate pathway components, however, are toxic. Bioactivation (toxification) may occur when the glutathione S-conjugate (or mercapturate) is converted to a cysteine S-conjugate that undergoes a β-lyase reaction. If the sulfhydryl-containing fragment produced in this reaction is reactive, toxicity may ensue. Some drugs and halogenated workplace/environmental contaminants are bioactivated by this mechanism. On the other hand, cysteine S-conjugate β-lyases occur in nature as a means of generating some biologically useful sulfhydryl-containing compounds.
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17
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Luo YS, Cichocki JA, McDonald TJ, Rusyn I. Simultaneous detection of the tetrachloroethylene metabolites S-(1,2,2-trichlorovinyl) glutathione, S-(1,2,2-trichlorovinyl)-L-cysteine, and N-acetyl-S-(1,2,2-trichlorovinyl)-L-cysteine in multiple mouse tissues via ultra-high performance liquid chromatography electrospray ionization tandem mass spectrometry. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2017; 80:513-524. [PMID: 28696834 PMCID: PMC5749336 DOI: 10.1080/15287394.2017.1330585] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Tetrachloroethylene (perchloroethylene; PERC) is a high-production volume chemical and ubiquitous environmental contaminant that is hazardous to human health. Toxicity attributed to PERC is mediated through oxidative and glutathione (GSH) conjugation metabolites. The conjugation of PERC by glutathione-s-transferase to generate S-(1,2,2-trichlorovinyl) glutathione (TCVG), which is subsequently metabolized to form S-(1,2,2-trichlorovinyl)-L-cysteine (TCVC) is of special importance to human health. Specifically, TCVC may be metabolized to N-acetyl-S-(1,2,2-trichlorovinyl)-L-cysteine (NAcTCVC) which is excreted through urine, or to electrophilic metabolites that are nephrotoxic and mutagenic. Little is known regarding toxicokinetics of TCVG, TCVC, and NAcTCVC as analytical methods for simultaneous determination of these metabolites in tissues have not yet been reported. Hence, an ultra-high-performance liquid chromatography electrospray ionization tandem mass spectrometry-based method was developed for analysis of TCVG, TCVC, and NAcTCVC in liver, kidneys, serum, and urine. The method is rapid, sensitive, robust, and selective for detection all three analytes in every tissue examined, with limits of detection (LOD) ranging from 1.8 to 68.2 femtomoles on column, depending on the analyte and tissue matrix. This method was applied to quantify levels of TCVG, TCVC, and NAcTCVC in tissues from mice treated with PERC (10 to 1000 mg/kg, orally) with limits of quantitation (LOQ) of 1-2.5 pmol/g in liver, 1-10 pmol/g in kidney, 1-2.5 pmol/ml in serum, and 2.5-5 pmol/ml in urine. This method is useful for further characterization of the GSH conjugative pathway of PERC in vivo and improved understanding of PERC toxicity.
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Affiliation(s)
- Yu-Syuan Luo
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA
| | - Joseph A. Cichocki
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA
| | - Thomas J. McDonald
- Department of Environmental and Occupational Health, Texas A&M University, College Station, TX, USA
| | - Ivan Rusyn
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, USA
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18
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Azevedo AMO, Pereira SAP, Passos MLC, Costa SPF, Pinto PCAG, Araujo ARTS, Saraiva MLMFS. Assessment of ionic liquids' toxicity through the inhibition of acylase I activity on a microflow system. CHEMOSPHERE 2017; 173:351-358. [PMID: 28126569 DOI: 10.1016/j.chemosphere.2016.12.138] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 12/06/2016] [Accepted: 12/27/2016] [Indexed: 06/06/2023]
Abstract
Acylase I (ACY I) plays a role in the detoxication and bioactivation of xenobiotics as well in other physiological functions. In this context, an automated ACY I assay for the evaluation of ionic liquids' (ILs) toxicity was developed. The assay was implemented in a sequential injection analysis (SIA) system and was applied to eight commercially available ILs. The SIA methodology was based on the deacetylation of N-acetyl-l-methionine with production of l-methionine, which was determined using fluorescamine. ACY I inhibition in the presence of ILs was monitored by the decrease of fluorescence intensity. The obtained results confirmed the influence of ILs' structural elements on its toxicity and revealed that pyridinium and phosphonium cations, longer alkyl side chains and tetrafluoroborate anion displayed higher toxic effect on enzyme activity. The developed methodology proved to be robust and exhibited good repeatability (RSD < 1.3%, n = 10), leading also to a reduction of reagents consumption and effluents production. Thus, it is expected that the proposed assay can be used as a novel tool for ILs' toxicity screening.
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Affiliation(s)
- Ana M O Azevedo
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Sarah A P Pereira
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; Escola Superior de Saúde, Instituto Politécnico da Guarda, Avenida Rainha D. Amélia, S/N, 6300-749 Guarda, Portugal
| | - Marieta L C Passos
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Susana P F Costa
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Paula C A G Pinto
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; A3D - Association for Drug Discovery and Development, Aveiro, Portugal
| | - André R T S Araujo
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal; Unidade de Investigação para o Desenvolvimento do Interior, Instituto Politécnico da Guarda, Avenida Dr. Francisco de Sá Carneiro, 50, 6300-559 Guarda, Portugal
| | - M Lúcia M F S Saraiva
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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19
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A AH, Ali F, Kushwaha S, Taye N, Chattopadhyay S, Das A. A Cysteine-Specific Fluorescent Switch for Monitoring Oxidative Stress and Quantification of Aminoacylase-1 in Blood Serum. Anal Chem 2016; 88:12161-12168. [DOI: 10.1021/acs.analchem.6b03066] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Anila H A
- Organic
Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Firoj Ali
- Organic
Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Shilpi Kushwaha
- Organic
Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Nandaraj Taye
- Chromatin
and Disease Laboratory, National Center for Cell Science, Pune 411007, India
| | - Samit Chattopadhyay
- Chromatin
and Disease Laboratory, National Center for Cell Science, Pune 411007, India
- CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Amitava Das
- Organic
Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
- CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar 364002, Gujrat, India
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20
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Stocker P, Brunel JM, de Rezende L, -do Amaral AT, Morelli X, Roche P, Vidal N, Giardina T, Perrier J. Aminoacylase 1-catalysed deacetylation of bioactives epoxides mycotoxin-derived mercapturates; 3,4-epoxyprecocenes as models of cytotoxic epoxides. Biochimie 2012; 94:1668-75. [DOI: 10.1016/j.biochi.2012.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 01/10/2012] [Indexed: 12/25/2022]
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21
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Tsirulnikov K, Abuladze N, Bragin A, Faull K, Cascio D, Damoiseaux R, Schibler MJ, Pushkin A. Inhibition of aminoacylase 3 protects rat brain cortex neuronal cells from the toxicity of 4-hydroxy-2-nonenal mercapturate and 4-hydroxy-2-nonenal. Toxicol Appl Pharmacol 2012; 263:303-14. [PMID: 22819785 DOI: 10.1016/j.taap.2012.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 06/11/2012] [Accepted: 07/02/2012] [Indexed: 12/21/2022]
Abstract
4-Hydroxy-2-nonenal (4HNE) and acrolein (ACR) are highly reactive neurotoxic products of lipid peroxidation that are implicated in the pathogenesis and progression of Alzheimer's and Parkinson's diseases. Conjugation with glutathione (GSH) initiates the 4HNE and ACR detoxification pathway, which generates the mercapturates of 4HNE and ACR that can be excreted. Prior work has shown that the efficiency of the GSH-dependent renal detoxification of haloalkene derived mercapturates is significantly decreased upon their deacetylation because of rapid transformation of the deacetylated products into toxic compounds mediated by β-lyase. The enzymes of the GSH-conjugation pathway and β-lyases are expressed in the brain, and we hypothesized that a similar toxicity mechanism may be initiated in the brain by the deacetylation of 4HNE- and ACR-mercapturate. The present study was performed to identify an enzyme(s) involved in 4HNE- and ACR-mercapturate deacetylation, characterize the brain expression of this enzyme and determine whether its inhibition decreases 4HNE and 4HNE-mercapturate neurotoxicity. We demonstrated that of two candidate deacetylases, aminoacylases 1 (AA1) and 3 (AA3), only AA3 efficiently deacetylates both 4HNE- and ACR-mercapturate. AA3 was further localized to neurons and blood vessels. Using a small molecule screen we generated high-affinity AA3 inhibitors. Two of them completely protected rat brain cortex neurons expressing AA3 from the toxicity of 4HNE-mercapturate. 4HNE-cysteine (4HNE-Cys) was also neurotoxic and its toxicity was mostly prevented by a β-lyase inhibitor, aminooxyacetate. The results suggest that the AA3 mediated deacetylation of 4HNE-mercapturate may be involved in the neurotoxicity of 4HNE.
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Affiliation(s)
- Kirill Tsirulnikov
- Department of Medicine, University of California at Los Angeles, CA 90095-1689, USA
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22
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Abstract
Trichloroethylene (TCE) is one of the most widespread environmental contaminants, which is metabolized to N-acetyl-S-1,2-dichlorovinyl-L-cysteine (NA-DCVC) before being excreted in the urine. Alternatively, NA-DCVC can be deacetylated by aminoacylase 3 (AA3), an enzyme that is highly expressed in the kidney, liver, and brain. NA-DCVC deacetylation initiates the transformation into toxic products that ultimately causes acute renal failure. AA3 inhibition is therefore a target of interest to prevent TCE induced nephrotoxicity. Here we report the crystal structure of recombinant mouse AA3 (mAA3) in the presence of its acetate byproduct and two substrates: N(α)-acetyl-L-tyrosine and NA-DCVC. These structures, in conjunction with biochemical data, indicated that AA3 mediates substrate specificity through van der Waals interactions providing a dynamic interaction interface, which facilitates a diverse range of substrates.
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Nolin TD, Ouseph R, Himmelfarb J, McMenamin ME, Ward RA. Multiple-dose pharmacokinetics and pharmacodynamics of N-acetylcysteine in patients with end-stage renal disease. Clin J Am Soc Nephrol 2010; 5:1588-94. [PMID: 20538838 DOI: 10.2215/cjn.00210110] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND OBJECTIVES ESRD is associated with systemic oxidative stress, an important nontraditional risk factor for the development of cardiovascular disease. Since interventions aimed at reducing oxidative stress may be beneficial, we examined the pharmacokinetics and pharmacodynamics of the widely used antioxidant N-acetylcysteine (NAC) after oral administration in patients with ESRD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Twenty-four ESRD patients were randomly assigned to receive 600 or 1200 mg of sustained-release NAC orally every 12 hours for 14 days. Seven healthy control subjects received NAC 600 mg in the same manner. Blood samples were obtained on days 1 and 15 for determination of NAC pharmacokinetics and pharmacodynamics. RESULTS Significant dose-related increases in NAC plasma concentrations were observed in ESRD patients with no change in total clearance; a doubling of the dose resulted in a 2-fold increase in NAC area under the plasma concentration-time curve (AUC). However, NAC clearance was reduced by 90% in ESRD, leading to a 7-fold larger AUC and 13-fold longer half-life compared with healthy control subjects. NAC administration resulted in a significant reduction in total homocysteine plasma concentrations in ESRD and healthy subjects, but had no effect on several other oxidative stress markers. CONCLUSIONS These findings indicate that the total clearance of oral NAC is significantly reduced in ESRD patients, leading to marked increases in systemic exposure, and suggest that NAC may have a limited role in the chronic treatment of oxidative stress-related illness.
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Affiliation(s)
- Thomas D Nolin
- University of Pittsburgh School of Pharmacy, Department of Pharmacy & Therapeutics, Pittsburgh, PA 15261, USA.
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24
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Abstract
Many potentially toxic electrophiles react with glutathione to form glutathione S-conjugates in reactions catalyzed or enhanced by glutathione S-transferases. The glutathione S-conjugate is sequentially converted to the cysteinylglycine-, cysteine- and N-acetyl-cysteine S-conjugate (mercapturate). The mercapturate is generally more polar and water soluble than the parent electrophile and is readily excreted. Excretion of the mercapturate represents a detoxication mechanism. Some endogenous compounds, such as leukotrienes, prostaglandin (PG) A2, 15-deoxy-Δ12,14-PGJ2, and hydroxynonenal can also be metabolized to mercapturates and excreted. On occasion, however, formation of glutathione S- and cysteine S-conjugates are bioactivation events as the metabolites are mutagenic and/or cytotoxic. When the cysteine S-conjugate contains a strong electron-withdrawing group attached at the sulfur, it may be converted by cysteine S-conjugate β-lyases to pyruvate, ammonium and the original electrophile modified to contain an –SH group. If this modified electrophile is highly reactive then the enzymes of the mercapturate pathway together with the cysteine S-conjugate β-lyases constitute a bioactivation pathway. Some endogenous halogenated environmental contaminants and drugs are bioactivated by this mechanism. Recent studies suggest that coupling of enzymes of the mercapturate pathway to cysteine S-conjugate β-lyases may be more common in nature and more widespread in the metabolism of electrophilic xenobiotics than previously realized.
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25
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Oboh OT, Lamango NS. Liver prenylated methylated protein methyl esterase is the same enzyme as Sus scrofa carboxylesterase. J Biochem Mol Toxicol 2008; 22:51-62. [PMID: 18273909 DOI: 10.1002/jbt.20214] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The C-terminal --COOH of prenylated proteins is methylated to --COOCH3. The --COOCH3 ester forms are hydrolyzed by prenylated methylated protein methyl esterase (PMPMEase) to the original acid forms. This is the only reversible step of the prenylation pathway. PMPMEase has not been purified and identified and is therefore understudied. Using a prenylated-L-cysteine methyl ester as substrate, PMPMEase was purified to apparent homogeneity from porcine liver supernatant. SDS-PAGE analysis revealed an apparent mass of 57 kDa. Proteomics analyses identified 17 peptides (242 amino acids). A Mascot database search revealed these as portions of the Sus scrofa carboxylesterase, a 62-kDa serine hydrolase with the C-terminal HAEL endoplasmic reticulum-retention signal. It is at least 71% identical to such mammalian carboxylesterases as human carboxylesterase 1 with affinities toward hydrophobic substrates and known to activate prodrugs, metabolize active drugs, as well as detoxify various substances such as cocaine and food-derived esters. The purified enzyme hydrolyzed benzoyl-Gly-farnesyl-L-cysteine methyl ester and hydrocinamoyl farnesyl-L-cysteine methyl ester with Michaelis-Menten constant (K(m)) values of 33 +/- 4 and 25 +/- 4 microM and V(max) values of 4.51 +/- 0.28 and 6.80 +/- 0.51 nmol/min/mg of protein, respectively. It was inhibited by organophosphates, chloromethyl ketones, ebelactone A and B, and phenylmethylsulfonyl fluoride.
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Affiliation(s)
- Onovughode T Oboh
- College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA
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Pushkin A, Kurtz I. Measurement of aminoacylases. CURRENT PROTOCOLS IN TOXICOLOGY 2008; Chapter 6:Unit6.14. [PMID: 23045009 DOI: 10.1002/0471140856.tx0614s35] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The unit describes the assays for aminoacylase activity, with specific emphasis on aminoacylase III. The methods are based on the determination of deacetylated products of the aminoacylase-catalyzed reactions in fluorescence and absorbance assays. The unit also provides methods for isolation of the aminoacylase III from tissues and bacterial or mammalian cells and subsequent purification and analysis.
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Fishbane S. N-acetylcysteine in the prevention of contrast-induced nephropathy. Clin J Am Soc Nephrol 2007; 3:281-7. [PMID: 18003766 DOI: 10.2215/cjn.02590607] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND AND OBJECTIVES Contrast-induced nephropathy (CIN) is a common clinical problem that is growing in importance as an increasing number of tests and procedures that utilize contrast media are performed. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS The biological and pharmacological properties of n-acetylcysteine (NAC) are reviewed, as well as the current literature relevant to the ability of NAC to prevent CIN. RESULTS After publication of a seminal study by Tepel et al. in 2000, there has been a surge in interest regarding the ability of NAC to reduce the risk for CIN. Since then a large number of studies, mostly with relatively small sample sizes, have been published. CONCLUSIONS The results have been remarkably varied with some studies finding great efficacy with NAC but most finding no significant benefit.
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Ryazantsev S, Abuladze N, Newman D, Bondar G, Kurtz I, Pushkin A. Structural characterization of dimeric murine aminoacylase III. FEBS Lett 2007; 581:1898-902. [PMID: 17434493 DOI: 10.1016/j.febslet.2007.03.088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 03/14/2007] [Accepted: 03/22/2007] [Indexed: 01/08/2023]
Abstract
Aminoacylase III (AAIII) plays an important role in deacetylation of acetylated amino acids and N-acetylated S-cysteine conjugates of halogenated alkenes and alkanes. AAIII, recently cloned from mouse kidney and partially characterized, is a mixture of tetramers and dimers. In the present work, AAIII dimers were purified and shown to be enzymatically active. Limited trypsinolysis showed two domains of approximately 9 and 25 kDa. The three-dimensional structure of the dimer was studied by electron microscopy of negative stained samples and by single-particle reconstruction. A 16A resolution model of the AAIII dimer was created. It has an unusual, cage-like, structure. A realistic AAIII tetramer model was built from two dimers.
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Affiliation(s)
- Sergey Ryazantsev
- Department of Biological Chemistry, David Geffen School of Medicine, University of California at Los Angeles, Room 33-080 CHS, 10833 Le Conte Avenue, CA 90095-1689, USA
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29
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Raftos JE, Whillier S, Chapman BE, Kuchel PW. Kinetics of uptake and deacetylation of N-acetylcysteine by human erythrocytes. Int J Biochem Cell Biol 2007; 39:1698-706. [PMID: 17544838 DOI: 10.1016/j.biocel.2007.04.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 04/17/2007] [Accepted: 04/18/2007] [Indexed: 01/23/2023]
Abstract
Overproduction of reactive oxygen species associated with several diseases including sickle cell anaemia reduces the concentration of glutathione, a principal cellular antioxidant. Glutathione depletion in sickle erythrocytes increases their conversion to irreversible sickle cells that promote vaso-occlusion. Therapeutically, N-acetylcysteine partially restores glutathione concentrations but its mode of action is controversial. Following glutathione depletion, glutathione synthesis is limited by the supply of cysteine and it has been assumed that deacetylation of N-acetylcysteine within erythrocytes provides cysteine to accelerate glutathione production. To determine whether this is the case we studied the kinetics of transport and deacetylation of N-acetylcysteine. Uptake of N-acetylcysteine had a first order rate constant of 2.40+/-0.070min(-1) and only saturated above 10mM. Inhibition experiments showed that 56% of N-acetylcysteine transport was via the anion exchange protein. Deacetylation, measured using (1)H NMR, had a K(m) of 1.49+/-0.16mM and V(max) of 2.61+/-0.08micromolL(-1)min(-1). Oral doses of N-acetylcysteine increase glutathione concentrations in sickle erythrocytes at plasma N-acetylcysteine concentrations of approximately 10microM. At this concentration, calculated rates of N-acetylcysteine uptake and deacetylation were approximately 5% of the rate required to maintain normal glutathione production. We concluded that on oral administration, intracellular deacetylation of N-acetylcysteine supplies little of the cysteine required for accelerated glutathione production. Instead, N-acetylcysteine acts by freeing bound cysteine in the plasma that then enters the erythrocytes. To be effective, intracellular cysteine precursors must be designed to enter erythrocytes rapidly and employ enzymes with high activity within erythrocytes to liberate the cysteine.
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Affiliation(s)
- Julia E Raftos
- Department of Biological Sciences, Macquarie University, NSW 2109, Australia.
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Newman D, Abuladze N, Scholz K, Dekant W, Tsuprun V, Ryazantsev S, Bondar G, Sassani P, Kurtz I, Pushkin A. Specificity of Aminoacylase III-Mediated Deacetylation of Mercapturic Acids. Drug Metab Dispos 2006; 35:43-50. [PMID: 17012540 DOI: 10.1124/dmd.106.012062] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Trichloroethylene (TCE) and other halogenated alkenes are known environmental contaminants with cytotoxic and nephrotoxic effects, and are potential carcinogens. Their metabolism via the mercapturate metabolic pathway was shown to lead to their detoxification. The final products of this pathway, mercapturic acids or N-acetyl-l-cysteine S-conjugates, are secreted into the lumen in the renal proximal tubule. The proximal tubule may also deacetylate mercapturic acids, and the resulting cysteine S-conjugates are transformed by cysteine S-conjugate beta-lyases to nephrotoxic reactive thiols. The specificity and rate of mercapturic acid deacetylation may determine the toxicity of certain mercapturic acids; however, the exact enzymologic processes involved are not known in detail. In the present study we characterized the kinetics of the recently cloned mouse aminoacylase III (AAIII) toward a wide spectrum of halogenated mercapturic acids and N-acetylated amino acids. In general, the V(max) value of AAIII was significantly larger with chlorinated and brominated mercapturic acids, whereas fluorination significantly decreased it. The enzyme deacetylated mercapturic acids derived from the TCE metabolism including N-acetyl-S-(1,2-dichlorovinyl)-l-cysteine (NA-1,2-DCVC) and N-acetyl-S-(2,2-dichlorovinyl)-l-cysteine (NA-2,2-DCVC). Both mercapturic acids induced cytotoxicity in mouse proximal tubule mPCT cells expressing AAIII, which was decreased by an inhibitor of beta-lyase, aminooxyacetate. The toxic effect of NA-2,2-DCVC was smaller than that of NA-1,2-DCVC, indicating that factors other than the intracellular activity of AAIII mediate the cytotoxicity of these mercapturic acids. Our results indicate that in proximal tubule cells, AAIII plays an important role in deacetylating several halogenated mercapturic acids, and this process may be involved in their cyto- and nephrotoxicity.
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Affiliation(s)
- Debra Newman
- Division of Nephrology, David Geffen School of Medicine at UCLA, 10833 Le Conte Avenue, 7-155 Factor Building, Los Angeles, CA 90095-1689, USA
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31
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Perrier J, Durand A, Giardina T, Puigserver A. The rat kidney acylase 1. Evidence for a new cDNA form and comparisons with the porcine intestinal enzyme. Comp Biochem Physiol B Biochem Mol Biol 2004; 138:277-83. [PMID: 15253876 DOI: 10.1016/j.cbpc.2004.04.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Revised: 04/04/2004] [Accepted: 04/05/2004] [Indexed: 11/22/2022]
Abstract
A new cDNA form encoding the rat kidney acylase I was characterized and found to show as much as 93.5% identity in its translated nucleotide sequence and, to a lesser extent, in its 3'-untranslated region with the nucleotide sequence we previously reported in 2000. Comparisons between the amino acid sequences of the two corresponding proteins showed the presence of N-terminal fragments with 88.5% identity and different cysteine profiles. The cDNA nucleotide sequence of the pig intestinal enzyme isolated from a marathon library turned out to be 100% identical to that of the kidney enzyme, but differed from those of the two rat kidney acylase I forms.
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Affiliation(s)
- Josette Perrier
- Institut Méditerranéen de Recherche en Nutrition, INRA-UMR 1111 service 342, Faculté des Sciences et Techniques Saint-Jérôme, Avenue Escadrille Normandie Niemen, F-13397 Marseille cedex 20, France.
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32
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Pushkin A, Carpenito G, Abuladze N, Newman D, Tsuprun V, Ryazantsev S, Motemoturu S, Sassani P, Solovieva N, Dukkipati R, Kurtz I. Structural characterization, tissue distribution, and functional expression of murine aminoacylase III. Am J Physiol Cell Physiol 2004; 286:C848-56. [PMID: 14656720 DOI: 10.1152/ajpcell.00192.2003] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many xenobiotics are detoxified through the mercapturate metabolic pathway. The final product of the pathway, mercapturic acids ( N-acetylcysteine S-conjugates), are secreted predominantly by renal proximal tubules. Mercapturic acids may undergo a transformation mediated by aminoacylases and cysteine S-conjugate β-lyases that leads to nephrotoxic reactive thiol formation. The deacetylation of cysteine S-conjugates of N-acyl aromatic amino acids is thought to be mediated by an aminoacylase whose molecular identity has not been determined. In the present study, we cloned aminoacylase III, which likely mediates this process in vivo, and characterized its function and structure. The enzyme consists of 318 amino acids and has a molecular mass (determined by SDS-PAGE) of ∼35 kDa. Under nondenaturing conditions, the molecular mass of the enzyme is ∼140 kDa as determined by size-exclusion chromatography, which suggests that it is a tetramer. In agreement with this hypothesis, transmission electron microscopy and image analysis of aminoacylase III showed that the monomers of the enzyme are arranged with a fourfold rotational symmetry. Northern analysis demonstrated an ∼1.4-kb transcript that was expressed predominantly in kidney and showed less expression in liver, heart, small intestine, brain, lung, testis, and stomach. In kidney, aminoacylase III was immunolocalized predominantly to the apical domain of S1 proximal tubules and the cytoplasm of S2 and S3 proximal tubules. The data suggest that in kidney proximal tubules, aminoacylase III plays an important role in deacetylating mercapturic acids. The predominant cytoplasmic localization of aminoacylase III may explain the greater sensitivity of the proximal straight tubule to the nephrotoxicity of mercapturic acids.
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Affiliation(s)
- Alexander Pushkin
- Division of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095-1689, USA.
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33
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Ahola T, Lapatto R, Raivio KO, Selander B, Stigson L, Jonsson B, Jonsbo F, Esberg G, Stövring S, Kjartansson S, Stiris T, Lossius K, Virkola K, Fellman V. N-acetylcysteine does not prevent bronchopulmonary dysplasia in immature infants: a randomized controlled trial. J Pediatr 2003; 143:713-9. [PMID: 14657813 DOI: 10.1067/s0022-3476(03)00419-0] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To evaluate whether N-acetylcysteine (NAC) infusion during the first week of life reduces the risk of death or bronchopulmonary dysplasia (BPD) in infants with extremely low birth weight. Study design In a Nordic multicenter, double-blind trial, infants (n=391) weighing 500 to 999 g and on ventilator or nasal continuous positive airway pressure were randomized before the age of 36 hours to receive NAC 16 to 32 mg/kg/d (n=194) or placebo (n=197) intravenously for 6 days. Primary end points were death or BPD, defined as supplementary oxygen requirement at 36 weeks' gestational age. RESULTS There was no difference in the combined incidence of the primary end points death or BPD, 51% vs. 49%, between the NAC group and control group. Also similar was the incidence of BPD in survivors at 36 weeks' gestational age, 40% vs. 40%, and the mean oxygen requirement at the age of 28 days, 31.2% vs. 30.7%, respectively. The severity of BPD was similar in both groups. CONCLUSIONS A 6-day course of intravenous N-acetylcysteine at the dosage used does not prevent BPD or death in infants with extremely low birth weight.
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Affiliation(s)
- Terhi Ahola
- Hospital for Children and Adolescents, Helsinki University Central Hospital, Helsinki, Finland
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34
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Durand A, Giardina T, Villard C, Roussel A, Puigserver A, Perrier J. Rat kidney acylase I: further characterisation and mutation studies on the involvement of Glu 147 in the catalytic process. Biochimie 2003; 85:953-62. [PMID: 14644550 DOI: 10.1016/j.biochi.2003.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Rat kidney acylase I was characterised by performing site-directed mutagenesis and enzymatic analysis in the presence of various chemical inhibitors. Site-directed mutagenesis on E147 and overexpression of the protein in a bacterial system, revealed the importance of this residue in enzymatic activity, it corresponds to the putative catalytic E175 in carboxypeptidase G2 from Pseudomonas aeruginosa. The reactivity of histidine and cysteine residues of acylase I with diethylpyrocarbonate (DEPC) and mercuric chloride, respectively, showed that these two amino acids are required for the enzyme to be fully active. Interestingly, the effects of mercuric chloride on rat kidney acylase I were not as great as those on the porcine enzyme, in agreement with previously observed differences between the two enzymes. Moreover, N-[3-(2-furyl)-acryloyl-L-methionine] (FA-Met) a synthetic substrate of the porcine acylase I was found to be an inhibitor of the rat kidney enzyme. These results strongly suggest the existence of differences between the active site of rat and porcine kidney acylases I. Lastly, the rat kidney enzyme was as sensitive as its porcine counterpart to two metal chelating agents, 1,10-phenanthroline and ethylenediamine tetraacetate (EDTA).
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Affiliation(s)
- Anne Durand
- Faculté des Sciences et Techniques Saint-Jérôme, Institut Méditerranéen de Recherche en Nutrition, Service 342, Umr Université Aix-Marseille III-INRA 1111, avenue Escadrille-Normandie-Niemen, 13397 Marseille cedex 20, France
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35
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Stödeman M, Schwarz FP. Importance of product inhibition in the kinetics of the acylase hydrolysis reaction by differential stopped flow microcalorimetry. Anal Biochem 2002; 308:285-93. [PMID: 12419341 DOI: 10.1016/s0003-2697(02)00339-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The hydrolysis of N-acetyl-L-methionine, N-acetylglycine, N-acetyl-L-phenylalanine, and N-acetyl-L-alanine at 298.35K by porcine kidney acylase I (EC 3.5.1.14) was monitored by the heat released upon mixing of the substrate and enzyme in a differential stopped flow microcalorimeter. Values for the Michaelis constant (K(m)) and the catalytic constant (k(cat)) were determined from the progress of the reaction curve employing the integrated form of the Michaelis-Menten equation for each reaction mixture. When neglecting acetate product inhibition of the acylase, values for k(cat) were up to a factor of 2.3 larger than those values determined from reciprocal initial velocity-initial substrate concentration plots for at least four different reaction mixtures. In addition, values for K(m) were observed to increase linearly with an increase in the initial substrate concentration. When an acetate product inhibition constant of 600+/-31M(-1), determined by isothermal titration calorimetry, was used in the progress curve analysis, values for K(m) and k(cat) were in closer agreement with their values determined from the reciprocal initial velocity versus initial substrate concentration plots. The reaction enthalpies, Delta(r)H(cal), which were determined from the integrated heat pulse per amount of substrate in the reaction mixture, ranged from -4.69+/-0.09kJmol(-1) for N-acetyl-L-phenylalanine to -1.87+/-0.23kJmol(-1) for N-acetyl-L-methionine.
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Affiliation(s)
- Magnus Stödeman
- Center for Advanced Research in Biotechnology/National Institute of Standards and Technology, Rockville, MD 20850, USA
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36
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Cooper AJL, Bruschi SA, Anders MW. Toxic, halogenated cysteine S-conjugates and targeting of mitochondrial enzymes of energy metabolism. Biochem Pharmacol 2002; 64:553-64. [PMID: 12167474 DOI: 10.1016/s0006-2952(02)01076-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Several haloalkenes are metabolized in part to nephrotoxic cysteine S-conjugates; for example, trichloroethylene and tetrafluoroethylene are converted to S-(1,2-dichlorovinyl)-L-cysteine (DCVC) and S-(1,1,2,2-tetrafluoroethyl)-L-cysteine (TFEC), respectively. Although DCVC-induced toxicity has been investigated since the 1950s, the toxicity of TFEC and other haloalkene-derived cysteine S-conjugates has been studied more recently. Some segments of the US population are exposed to haloalkenes either through drinking water or in the workplace. Therefore, it is important to define the toxicological consequences of such exposures. Most halogenated cysteine S-conjugates are metabolized by cysteine S-conjugate beta-lyases to pyruvate, ammonia, and an alpha-chloroenethiolate (with DCVC) or an alpha-difluoroalkylthiolate (with TFEC) that may eliminate halide to give a thioacyl halide, which reacts with epsilon-amino groups of lysine residues in proteins. Nine mammalian pyridoxal 5'-phosphate (PLP)-containing enzymes catalyze cysteine S-conjugate beta-lyase reactions, including mitochondrial aspartate aminotransferase (mitAspAT), and mitochondrial branched-chain amino acid aminotransferase (BCAT(m)). Most of the cysteine S-conjugate beta-lyases are syncatalytically inactivated. TFEC-induced toxicity is associated with covalent modification of several mitochondrial enzymes of energy metabolism. Interestingly, the alpha-ketoglutarate- and branched-chain alpha-keto acid dehydrogenase complexes (KGDHC and BCDHC), but not the pyruvate dehydrogenase complex (PDHC), are susceptible to inactivation. mitAspAT and BCAT(m) may form metabolons with KGDHC and BCDHC, respectively, but no PLP enzyme is known to associate with PDHC. Consequently, we hypothesize that not only do these metabolons facilitate substrate channeling, but they also facilitate toxicant channeling, thereby promoting the inactivation of proximate mitochondrial enzymes and the induction of mitochondrial dysfunction.
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Affiliation(s)
- Arthur J L Cooper
- Department of Biochemistry, Weill Medical College of Cornell University, New York, NY 10021, USA.
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37
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Rooseboom M, Vermeulen NPE, Groot EJ, Commandeur JNM. Tissue distribution of cytosolic beta-elimination reactions of selenocysteine Se-conjugates in rat and human. Chem Biol Interact 2002; 140:243-64. [PMID: 12204580 DOI: 10.1016/s0009-2797(02)00039-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Selenocysteine Se-conjugates (e.g. methylselenocysteine) have been shown to be potent chemopreventive and chemoprotective agents, and inducers of apoptosis. Although the mechanism of action remains to be elucidated, beta-elimination of these compounds by beta-lyase enzymes into corresponding selenols, pyruvate and ammonia is thought to be critical. This study describes in vitro beta-lyase activity in nine rat organs using three selenocysteine Se-conjugates and S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine. For all substrates the highest beta-elimination rates were found in kidney, followed by liver, while brain, spleen, heart, large and small intestine, thyroid and lung were of minor importance. Since liver plays an important role in beta-elimination, hepatic beta-lyase activity was extensively studied using 23 selenocysteine Se-conjugates and S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine and was compared with previously obtained renal beta-lyase data. The results showed that hepatic beta-lyase activities were 4-25-fold lower than the corresponding renal beta-lyase activities. Hepatic beta-elimination of the substrates appeared to be exclusively catalyzed by the pyridoxal 5'-phosphate-dependent beta-lyase enzyme kynureninase. Studies performed with human hepatic cytosols of three individuals showed that hepatic beta-lyase activity was 2-5-fold higher when compared with the previously obtained human renal activity. Significant correlation was obtained between human hepatic beta-lyase activities of three individuals. The relevance of this data for using SeCys-conjugates as chemopreventive and a chemoprotective agent is discussed. Based on the large differences in organ-selective beta-elimination and specific beta-lyase activity between rat and humans, the rat might not be a good model to investigate nephrotoxicity of cysteine S-conjugates, and chemoprevention and chemoprotection of SeCys-conjugates in man.
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Affiliation(s)
- Martijn Rooseboom
- Department of Pharmacochemistry, Division of Molecular Toxicology, Leiden/Amsterdam Center for Drug Research (LACDR), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
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38
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Yamauchi A, Ueda N, Hanafusa S, Yamashita E, Kihara M, Naito S. Tissue distribution of and species differences in deacetylation of N-acetyl-L-cysteine and immunohistochemical localization of acylase I in the primate kidney. J Pharm Pharmacol 2002; 54:205-12. [PMID: 11848284 DOI: 10.1211/0022357021778394] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Species differences in the biotransformation of N-acetyl-L-cysteine (NAC) have been investigated to evaluate the usefulness of NAC as a constituent in parenteral nutrition solutions in place of cysteine. The activity of NAC-deacetylating enzyme (acylase) was measured in various tissues of different species (rat, rabbit, dog, monkey, and man). Acylase activity was highest in the kidney in all species studied. Enzyme activity in the liver was 10 %-22 % of that in the kidney in the rat, rabbit, monkey, and man, but almost no hepatic activity was seen in the dog. NAC-deacetylating activity was very low in other organs. The tissue distribution of acylase I was determined by Western blotting and an immunohistochemical method employing specific antibody against porcine acylase I (EC 3.5.1.14). The immunoblotting study showed a 46-kDa protein band corresponding to porcine acylase I in the kidney of all species. In liver cytosol, 46 kDa and/or 29 kDa bands were observed in the rat, rabbit, monkey, and man, but not in the dog. In the immunohistochemical study, positive staining with anti-acylase I antibody was observed clearly in the renal proximal tubules in the monkey and man. These results suggested that the kidney and liver were the main organs responsible for the biotransformation of NAC to cysteine in mammals other than the dog.
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Affiliation(s)
- Aiko Yamauchi
- Department of Pharmaceutical Information Science, Graduate School of Pharmacy, The University of Tokushima, Japan.
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39
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Pombrio JM, Giangreco A, Li L, Wempe MF, Anders MW, Sweet DH, Pritchard JB, Ballatori N. Mercapturic acids (N-acetylcysteine S-conjugates) as endogenous substrates for the renal organic anion transporter-1. Mol Pharmacol 2001; 60:1091-9. [PMID: 11641438 DOI: 10.1124/mol.60.5.1091] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mercapturic acids are N-acetyl-L-cysteine S-conjugates that are formed from a range of endogenous and exogenous chemicals. Although the kidney is a major site for elimination of mercapturic acids, the transport mechanisms involved have not been identified. The present study examined whether mercapturic acids are substrates for the renal basolateral organic anion transporter-1 (Oat1) from rat kidney. This carrier mediates uptake of organic anions from the bloodstream in exchange for intracellular alpha-ketoglutarate. Uptake of [(3)H]p-aminohippuric acid (PAH) in Oat1-expressing Xenopus laevis oocytes was strongly inhibited by S-(2,4-dinitrophenyl)-N-acetyl-L-cysteine (DNP-NAC) and by all other mercapturic acids tested, including the endogenous mercapturic acid N-acetyl-leukotriene E(4). Inhibition by the mercapturic acids was competitive, which is consistent with the hypothesis that these compounds are substrates for Oat1. This conclusion was supported by the direct demonstration of saturable [(35)S]DNP-NAC uptake in Oat1-expressing oocytes. [(35)S]DNP-NAC uptake was inhibited by PAH and other mercapturic acids and was stimulated in oocytes preloaded with glutarate. The apparent K(m) value for DNP-NAC uptake was only 2 microM, indicating that this mercapturic acid is a high affinity substrate for Oat1. Together, these data indicate that clearance of endogenous mercapturic acids is an important function of the renal organic anion transporter.
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Affiliation(s)
- J M Pombrio
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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40
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Story SV, Grunden AM, Adams MW. Characterization of an aminoacylase from the hyperthermophilic archaeon Pyrococcus furiosus. J Bacteriol 2001; 183:4259-68. [PMID: 11418567 PMCID: PMC95316 DOI: 10.1128/jb.183.14.4259-4268.2001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aminoacylase was identified in cell extracts of the hyperthermophilic archaeon Pyrococcus furiosus by its ability to hydrolyze N-acetyl-L-methionine and was purified by multistep chromatography. The enzyme is a homotetramer (42.06 kDa per subunit) and, as purified, contains 1.0 +/- 0.48 g-atoms of zinc per subunit. Treatment of the purified enzyme with EDTA resulted in complete loss of activity. This was restored to 86% of the original value (200 U/mg) by treatment with ZnCl(2) (and to 74% by the addition of CoCl(2)). After reconstitution with ZnCl(2), the enzyme contained 2.85 +/- 0.48 g-atoms of zinc per subunit. Aminoacylase showed broad substrate specificity and hydrolyzed nonpolar N-acylated L amino acids (Met, Ala, Val, and Leu), as well as N-formyl-L-methionine. The high K(m) values for these compounds indicate that the enzyme plays a role in the metabolism of protein growth substrates rather than in the degradation of cellular proteins. Maximal aminoacylase activity with N-acetyl-L-methionine as the substrate occurred at pH 6.5 and a temperature of 100 degrees C. The N-terminal amino acid sequence of the purified aminoacylase was used to identify, in the P. furiosus genome database, a gene that encodes 383 amino acids. The gene was cloned and expressed in Escherichia coli by using two approaches. One involved the T7 lac promoter system, in which the recombinant protein was expressed as inclusion bodies. The second approach used the Trx fusion system, and this produced soluble but inactive recombinant protein. Renaturation and reconstitution experiments with Zn(2+) ions failed to produce catalytically active protein. A survey of databases showed that, in general, organisms that contain a homolog of the P. furiosus aminoacylase (> or = 50% sequence identity) utilize peptide growth substrates, whereas those that do not contain the enzyme are not known to be proteolytic, suggesting a role for the enzyme in primary catabolism.
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Affiliation(s)
- S V Story
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602, USA
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41
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Giardina T, Perrier J, Puigserver A. The rat kidney acylase I, characterization and molecular cloning. Differences with other acylases I. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:6249-55. [PMID: 11012679 DOI: 10.1046/j.1432-1327.2000.01712.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The soluble acylase I from rat kidney was purified to homogeneity using a five-step procedure. As the resulting protein was found to have a relative molecular mass of 125 kDa based on size-exclusion chromatography and 44 kDa based on SDS/PAGE, the native protein was taken to consist of three subunits. The amino-acid sequence of a peptide resulting from limited proteolysis of the polypeptide chain with proteinase K, which was determined by microsequencing (RHEFHALRAGFALDEGLA), was found to be very similar to the corresponding sequence of porcine kidney acylase I. However, as N-furyl-acryloyl-L-methionine, a synthetic substrate for porcine acylases, was not hydrolyzed by the rat enzyme, it was suggested that the polypeptide chain might differ in other respects from those of the other acylases I. A full length cDNA coding for the rat kidney acylase I was therefore isolated and found to contain a 1224-bp open reading frame encoding a protein consisting of 408 amino-acid residues, which corresponded to a calculated molecular mass of 45 847 Da per subunit. The deduced amino-acid sequence showed 93.6% and 87.2% identity with that of the human liver and porcine kidney, respectively.
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Affiliation(s)
- T Giardina
- Institut Méditerranéen de Recherche en Nutrition, CNRS-ESA 6033, Faculté des Sciences et Techniques Saint-Jérôme, Marseille Cedex 20, France
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