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Bondi CD, Hartman HL, Tan RJ. NRF2 in kidney physiology and disease. Physiol Rep 2024; 12:e15961. [PMID: 38418382 PMCID: PMC10901725 DOI: 10.14814/phy2.15961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/19/2024] [Accepted: 02/05/2024] [Indexed: 03/01/2024] Open
Abstract
The role of NRF2 in kidney biology has received considerable interest over the past decade. NRF2 transcriptionally controls genes responsible for cellular protection against oxidative and electrophilic stress and has anti-inflammatory functions. NRF2 is expressed throughout the kidney and plays a role in salt and water handling. In disease, animal studies show that NRF2 protects against tubulointerstitial damage and reduces interstitial fibrosis and tubular atrophy, and may slow progression of polycystic kidney disease. However, the role of NRF2 in proteinuric glomerular diseases is controversial. Although the NRF2 inducer, bardoxolone methyl (CDDO-Me), increases glomerular filtration rate in humans, it has not been shown to slow disease progression in diabetic kidney disease and Alport syndrome. Furthermore, bardoxolone methyl was associated with negative effects on fluid retention, proteinuria, and blood pressure. Several animal studies replicate findings of worsened proteinuria and a more rapid progression of kidney disease, although considerable controversy exists. It is clear that further study is needed to better understand the effects of NRF2 in the kidney. This review summarizes the available data to clarify the promise and risks associated with targeting NRF2 activity in the kidney.
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Affiliation(s)
- Corry D. Bondi
- Renal‐Electrolyte Division, Department of MedicineUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | - Hannah L. Hartman
- Renal‐Electrolyte Division, Department of MedicineUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | - Roderick J. Tan
- Renal‐Electrolyte Division, Department of MedicineUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
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2
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Arora S, Satija S, Mittal A, Solanki S, Mohanty SK, Srivastava V, Sengupta D, Rout D, Arul Murugan N, Borkar RM, Ahuja G. Unlocking The Mysteries of DNA Adducts with Artificial Intelligence. Chembiochem 2024; 25:e202300577. [PMID: 37874183 DOI: 10.1002/cbic.202300577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/18/2023] [Accepted: 10/23/2023] [Indexed: 10/25/2023]
Abstract
Cellular genome is considered a dynamic blueprint of a cell since it encodes genetic information that gets temporally altered due to various endogenous and exogenous insults. Largely, the extent of genomic dynamicity is controlled by the trade-off between DNA repair processes and the genotoxic potential of the causative agent (genotoxins or potential carcinogens). A subset of genotoxins form DNA adducts by covalently binding to the cellular DNA, triggering structural or functional changes that lead to significant alterations in cellular processes via genetic (e. g., mutations) or non-genetic (e. g., epigenome) routes. Identification, quantification, and characterization of DNA adducts are indispensable for their comprehensive understanding and could expedite the ongoing efforts in predicting carcinogenicity and their mode of action. In this review, we elaborate on using Artificial Intelligence (AI)-based modeling in adducts biology and present multiple computational strategies to gain advancements in decoding DNA adducts. The proposed AI-based strategies encompass predictive modeling for adduct formation via metabolic activation, novel adducts' identification, prediction of biochemical routes for adduct formation, adducts' half-life predictions within biological ecosystems, and, establishing methods to predict the link between adducts chemistry and its location within the genomic DNA. In summary, we discuss some futuristic AI-based approaches in DNA adduct biology.
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Affiliation(s)
- Sakshi Arora
- Department of Computational Biology, Indraprastha Institute of Information Technology (IIIT-Delhi) Okhla, Phase III, New Delhi, 110020, India
| | - Shiva Satija
- Department of Computational Biology, Indraprastha Institute of Information Technology (IIIT-Delhi) Okhla, Phase III, New Delhi, 110020, India
| | - Aayushi Mittal
- Department of Computational Biology, Indraprastha Institute of Information Technology (IIIT-Delhi) Okhla, Phase III, New Delhi, 110020, India
| | - Saveena Solanki
- Department of Computational Biology, Indraprastha Institute of Information Technology (IIIT-Delhi) Okhla, Phase III, New Delhi, 110020, India
| | - Sanjay Kumar Mohanty
- Department of Computational Biology, Indraprastha Institute of Information Technology (IIIT-Delhi) Okhla, Phase III, New Delhi, 110020, India
| | - Vaibhav Srivastava
- Division of Glycoscience, Department of Chemistry CBH School, Royal Institute of Technology (KTH) AlbaNova University Center, 10691, Stockholm, Sweden
| | - Debarka Sengupta
- Department of Computational Biology, Indraprastha Institute of Information Technology (IIIT-Delhi) Okhla, Phase III, New Delhi, 110020, India
| | - Diptiranjan Rout
- Department of Transfusion Medicine National Cancer Institute, AIIMS, New Delhi, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110608, India
| | - Natarajan Arul Murugan
- Department of Computational Biology, Indraprastha Institute of Information Technology (IIIT-Delhi) Okhla, Phase III, New Delhi, 110020, India
| | - Roshan M Borkar
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER)-Guwahati, Sila Katamur Halugurisuk P.O.: Changsari, Dist, Guwahati, Assam, 781101, India
| | - Gaurav Ahuja
- Department of Computational Biology, Indraprastha Institute of Information Technology (IIIT-Delhi) Okhla, Phase III, New Delhi, 110020, India
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3
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Rathmacher JA, Fuller JC, Abumrad NN, Flynn CR. Inflammation Biomarker Response to Oral 2-Hydroxybenzylamine (2-HOBA) Acetate in Healthy Humans. Inflammation 2023; 46:1343-1352. [PMID: 36935449 PMCID: PMC10025056 DOI: 10.1007/s10753-023-01801-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 02/28/2023] [Accepted: 03/02/2023] [Indexed: 03/21/2023]
Abstract
Inflammation is associated with the formation of reactive oxygen species (ROS) and the formation of lipid-derived compounds, such as isolevuglandins (IsoLGs), malondialdehyde, 4-hydroxy-nonenal, and 4-oxo-nonenal. The most reactive of these are the IsoLGs, which form covalent adducts with lysine residues and other cellular primary amines leading to changes in protein function, immunogenicity, and epigenetic alterations and have been shown to contribute to a number of inflammatory diseases. 2-Hydroxybenzylamine (2-HOBA) is a natural compound found in buckwheat seeds and reacts with all IsoLG adducts preventing adduct formation with proteins and DNA. Therefore, 2-HOBA is well positioned as an agent for the prevention of inflammatory-prone diseases. In this study, we examined the potential beneficial effects of 2-HOBA on oxidative stress and inflammatory biomarkers in two cohorts of healthy younger and older adults. We utilized the Olink® targeted inflammation panel before and after an oral 15-day treatment regimen with 2-HOBA. We found significant relative changes in the plasma concentration of 15 immune proteins that may reflect the in vivo immune targets of 2-HOBA. Treatment of 2-HOBA resulted in significant increased levels of CCL19, IL-12β, IL-20Rα, and TNFβ, whereas levels of TWEAK significantly decreased. Ingenuity Pathway Analysis identified canonical pathways regulated by the differentially secreted cytokines, chemokines, and growth factors upon 2-HOBA treatment and further points to biofunctions related to the recruitment, attraction, and movement of different immune cell types. In conclusion, 2-HOBA significantly altered the protein biomarkers CCL19, IL-12β, IL-20Rα, TNFβ, and TWEAK, and these may be responsible for the protective effects of 2-HOBA against reactive electrophiles, such as IsoLGs, commonly expressed in conditions of excessive oxidative stress. 2-HOBA has a role as a IsoLG scavenger to proactively improve immune health in a variety of conditions.
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Affiliation(s)
- John A Rathmacher
- MTI BioTech, Inc, Iowa State University Research Park, Ames, IA, USA
- Department of Animal Science, Iowa State University, Ames, IA, USA
| | | | - Naji N Abumrad
- MTI BioTech, Inc, Iowa State University Research Park, Ames, IA, USA
- Metabolic Technologies, LLC, Missoula, MT, USA
- Department of Surgery, Vanderbilt University Medical Center, MRBIV Room 8465A, Nashville, TN, 37232, USA
| | - Charles R Flynn
- Department of Surgery, Vanderbilt University Medical Center, MRBIV Room 8465A, Nashville, TN, 37232, USA.
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Barbasiewicz M, Fedoryński M, Loska R, Mąkosza M. Analogy of the Reactions of Aromatic and Aliphatic π- Electrophiles with Nucleophiles. Molecules 2023; 28:molecules28104015. [PMID: 37241756 DOI: 10.3390/molecules28104015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/01/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
The aim of this essay is to disclose the similarity of a great variety of reactions that proceed between nucleophiles and π-electrophiles-both aromatic and aliphatic. These reactions proceed via initial reversible addition, followed by a variety of transformations that are common for the adducts of both aliphatic and aromatic electrophiles. We hope that understanding of this analogy should help to expand the scope of the known reactions and inspire the search for new reactions that were overlooked.
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Affiliation(s)
| | - Michał Fedoryński
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Rafał Loska
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Mieczysław Mąkosza
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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5
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Hill J, Beckler TD, Crich D. Recent Advances in the Synthesis of Di- and Trisubstituted Hydroxylamines. Molecules 2023; 28:molecules28062816. [PMID: 36985788 PMCID: PMC10051932 DOI: 10.3390/molecules28062816] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/08/2023] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
As an underrepresented functional group in bioorganic and medicinal chemistry, the hydroxylamine unit has historically received little attention from the synthetic community. Recent developments, however, suggest that hydroxylamines may have broader applications such that a review covering recent developments in the synthesis of this functional group is timely. With this in mind, this review primarily covers developments in the past 15 years in the preparation of di- and trisubstituted hydroxylamines. The mechanism of the reactions and key features and shortcomings are discussed throughout the review.
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Affiliation(s)
- Jarvis Hill
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA 30602, USA
- Department of Chemistry, University of Georgia, 302 East Campus Road, Athens, GA 30602, USA
| | - Thomas D Beckler
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA 30602, USA
- Department of Chemistry, University of Georgia, 302 East Campus Road, Athens, GA 30602, USA
| | - David Crich
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA 30602, USA
- Department of Chemistry, University of Georgia, 302 East Campus Road, Athens, GA 30602, USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
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Wilkinson IVL, Castro-Falcón G, Roda-Serrat MC, Purdy TN, Straetener J, Brauny MM, Maier L, Brötz-Oesterhelt H, Christensen LP, Sieber SA, Hughes CC. The Cyanobacterial "Nutraceutical" Phycocyanobilin Inhibits Cysteine Protease Legumain. Chembiochem 2023; 24:e202200455. [PMID: 36538283 DOI: 10.1002/cbic.202200455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 12/19/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
The blue biliprotein phycocyanin, produced by photo-autotrophic cyanobacteria including spirulina (Arthrospira) and marketed as a natural food supplement or "nutraceutical," is reported to have anti-inflammatory, antioxidant, immunomodulatory, and anticancer activity. These diverse biological activities have been specifically attributed to the phycocyanin chromophore, phycocyanobilin (PCB). However, the mechanism of action of PCB and the molecular targets responsible for the beneficial properties of PCB are not well understood. We have developed a procedure to rapidly cleave the PCB pigment from phycocyanin by ethanolysis and then characterized it as an electrophilic natural product that interacts covalently with thiol nucleophiles but lacks any appreciable cytotoxicity or antibacterial activity against common pathogens and gut microbes. We then designed alkyne-bearing PCB probes for use in chemical proteomics target deconvolution studies. Target identification and validation revealed the cysteine protease legumain (also known as asparaginyl endopeptidase, AEP) to be a target of PCB. Inhibition of this target may account for PCB's diverse reported biological activities.
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Affiliation(s)
- Isabel V L Wilkinson
- Center for Protein Assemblies (CPA), Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 8, 85748, Garching, Germany
| | - Gabriel Castro-Falcón
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, CA 92093, USA
| | - Maria C Roda-Serrat
- Department of Green Technology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Trevor N Purdy
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, CA 92093, USA
| | - Jan Straetener
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076, Tübingen, Germany
| | - Melanie M Brauny
- Cluster of Excellence EXC 2124, Controlling Microbes to Fight Infection, University of Tübingen, 72076, Tübingen, Germany
- Microbiome-Host-Interaction Lab, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076, Tübingen, Germany
| | - Lisa Maier
- Cluster of Excellence EXC 2124, Controlling Microbes to Fight Infection, University of Tübingen, 72076, Tübingen, Germany
- Microbiome-Host-Interaction Lab, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076, Tübingen, Germany
| | - Heike Brötz-Oesterhelt
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076, Tübingen, Germany
- Cluster of Excellence EXC 2124, Controlling Microbes to Fight Infection, University of Tübingen, 72076, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, 72076, Tübingen, Germany
| | - Lars P Christensen
- Department of Green Technology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Stephan A Sieber
- Center for Protein Assemblies (CPA), Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 8, 85748, Garching, Germany
| | - Chambers C Hughes
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, CA 92093, USA
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, 72076, Tübingen, Germany
- Cluster of Excellence EXC 2124, Controlling Microbes to Fight Infection, University of Tübingen, 72076, Tübingen, Germany
- German Center for Infection Research, Partner Site Tübingen, 72076, Tübingen, Germany
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7
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Perez HL, Andonian C. A novel approach for the bioanalysis of short-lived aldehydes. Bioanalysis 2022; 14:1317-26. [PMID: 36541259 DOI: 10.4155/bio-2022-0187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Background: The instability of aldehydes in biological matrices is associated with their reactions with thiol and amino moieties in proteins. This chemical reaction is reversible by nature and highly pH dependent. Method: A novel approach that includes protein precipitation with an acidic solution of acetonitrile/water/formic acid (85/14/1; v/v/v) was developed to efficiently recover Aldehyde-1 from plasma by shifting the equilibrium toward the formation of the free form. Results: This enabled the support of two GLP studies where Aldehyde-1 was administered to mice. The recovery of Aldehyde-1 from plasma exceeded 88% at three concentration levels. Plasma stability was confirmed at ambient conditions for 24 h and in the freezer for at least 43 (-20°C) and 64 (-70°C) days.
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Wu H, Niu C, Qu Y, Sun X, Wang K. Selective activation of TRPA1 ion channels by nitrobenzene skin sensitizers DNFB and DNCB. J Biol Chem 2021; 298:101555. [PMID: 34973335 PMCID: PMC8800105 DOI: 10.1016/j.jbc.2021.101555] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 12/17/2021] [Accepted: 12/28/2021] [Indexed: 12/21/2022] Open
Abstract
2, 4-dinitrofluorobenzene (DNFB) and 2, 4-dinitrochlorobenzene (DNCB) are well known as skin sensitizers that can cause dermatitis. DNFB has shown to more potently sensitize skin; however, how DNFB and DNCB cause skin inflammation at a molecular level and why this difference in their sensitization ability is observed remains unknown. In this study, we aimed to identify the molecular targets and mechanisms on which DNFB and DNCB act. We used a fluorescent calcium imaging plate reader in an initial screening assay before patch-clamp recordings for validation. Molecular docking in combination with site-directed mutagenesis was then carried out to investigate DNFB and DNCB binding sites in the TRPA1 ion channel that may be selectively activated by these tow sensitizers. We found that DNFB and DNCB selectively activated TRPA1 channel with EC50 values of 2.3 ± 0.7 μM μM and 42.4 ± 20.9 μM, respectively. Single-channel recordings revealed that DNFB and DNCB increase the probability of channel opening and acts on three residues (C621, E625 and Y658) critical for TRPA1 activation. Our findings may not only help explain the molecular mechanism underlying the dermatitis and pruritus caused by chemicals like DNFB and DNCB, but also provide a molecular tool 7.5-fold more potent than the current TRPA1 activator allyl isothiocyanate (AITC) used for investigating TRPA1 channel pharmacology and pathology.
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Affiliation(s)
- Han Wu
- Department of Pharmacology, School of Pharmacy, Qingdao University, #1 Ningde Road, Qingdao 266073
| | - Canyang Niu
- Department of Pharmacology, School of Pharmacy, Qingdao University, #1 Ningde Road, Qingdao 266073
| | - Yaxuan Qu
- Department of Pharmacology, School of Pharmacy, Qingdao University, #1 Ningde Road, Qingdao 266073
| | - Xiaoying Sun
- Department of Pharmacology, School of Pharmacy, Qingdao University, #1 Ningde Road, Qingdao 266073; Institue of Innovative Drugs, Qingdao University, 38 Dengzhou Road, Qingdao 266021, China.
| | - KeWei Wang
- Department of Pharmacology, School of Pharmacy, Qingdao University, #1 Ningde Road, Qingdao 266073; Institue of Innovative Drugs, Qingdao University, 38 Dengzhou Road, Qingdao 266021, China.
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9
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Kamoshita S, Matsui S, Suto N, Sakurai K. Reactivity Analysis of New Multivalent Electrophilic Probes for Affinity Labeling of Carbohydrate Binding Proteins. Chembiochem 2021; 23:e202100388. [PMID: 34490706 DOI: 10.1002/cbic.202100388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/05/2021] [Indexed: 11/07/2022]
Abstract
We have designed and synthesized six different multivalent electrophiles as carbohydrate affinity labeling probes. Evaluation of the reactivity of the electrophiles against peanut agglutinin (PNA) and Ricinus communis agglutinin (RCA) showed that p- and m-aryl sulfonyl fluoride are effective protein reactive groups that label carbohydrate binding lectins in a ligand-dependent fashion at a nanomolar probe concentration. Analysis of the selectivity of affinity labeling in the presence of excess BSA as a nonspecific protein indicated that m-arylsulfonyl fluoride is a more selective protein-reactive group, albeit with attenuated reactivity. Further analysis showed that the labeling efficiency of the multivalent electrophilic probes can be improved by employing reaction conditions involving 25 °C instead of typically employed 4 °C. Both isomers of arylsulfonyl fluoride groups together represent promising affinity labels for target identification studies that could serve as more efficient alternatives to photoreactive groups.
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Affiliation(s)
- Shione Kamoshita
- Department of Bioengineering and Life Science, 4-24-16, Naka-cho, Koganei-shi, Tokyo, 184-8588, Japan
| | - Saho Matsui
- Department of Bioengineering and Life Science, 4-24-16, Naka-cho, Koganei-shi, Tokyo, 184-8588, Japan
| | - Nanako Suto
- Department of Bioengineering and Life Science, 4-24-16, Naka-cho, Koganei-shi, Tokyo, 184-8588, Japan
| | - Kaori Sakurai
- Department of Bioengineering and Life Science, 4-24-16, Naka-cho, Koganei-shi, Tokyo, 184-8588, Japan
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Abstract
Cholesterol is an essential component of mammalian plasma membranes. Alterations in sterol metabolism or oxidation have been linked to various pathological conditions, including cardiovascular diseases, cancer, and neurodegenerative disorders. Unsaturated sterols are vulnerable to oxidation induced by singlet oxygen and other reactive oxygen species. This process yields reactive sterol oxidation products, including hydroperoxides, epoxides as well as aldehydes. These oxysterols, in particular those with high electrophilicity, can modify nucleophilic sites in biomolecules and affect many cellular functions. Here, we review the generation and measurement of reactive sterol oxidation products with emphasis on cholesterol hydroperoxides and aldehyde derivatives (electrophilic oxysterols) and their effects on protein modifications.
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Affiliation(s)
- Sayuri Miyamoto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Rodrigo S Lima
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Alex Inague
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Lucas G Viviani
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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11
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Mąkosza M. Electrophilic and Nucleophilic Aromatic Substitutions are Mechanistically Similar with Opposite Polarity. Chemistry 2020; 26:15346-15353. [PMID: 33174247 DOI: 10.1002/chem.202003770] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Indexed: 11/07/2022]
Abstract
Confrontation of the recently formulated general mechanism of nucleophilic substitution in electron-deficient arenes with the well-known mechanism of electrophilic substitution revealed that these fundamental processes are mechanistically identical but proceed according to opposite polarity-an Umpolung relation. In this viewpoint this apparently controversial concept is supported by discussion of a variety of experimental results.
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Affiliation(s)
- Mieczysław Mąkosza
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw 42, Poland
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12
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Linzner N, Loi VV, Fritsch VN, Antelmann H. Thiol-based redox switches in the major pathogen Staphylococcus aureus. Biol Chem 2020; 402:333-361. [PMID: 33544504 DOI: 10.1515/hsz-2020-0272] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/05/2020] [Indexed: 12/15/2022]
Abstract
Staphylococcus aureus is a major human pathogen, which encounters reactive oxygen, nitrogen, chlorine, electrophile and sulfur species (ROS, RNS, RCS, RES and RSS) by the host immune system, during cellular metabolism or antibiotics treatments. To defend against redox active species and antibiotics, S. aureus is equipped with redox sensing regulators that often use thiol switches to control the expression of specific detoxification pathways. In addition, the maintenance of the redox balance is crucial for survival of S. aureus under redox stress during infections, which is accomplished by the low molecular weight (LMW) thiol bacillithiol (BSH) and the associated bacilliredoxin (Brx)/BSH/bacillithiol disulfide reductase (YpdA)/NADPH pathway. Here, we present an overview of thiol-based redox sensors, its associated enzymatic detoxification systems and BSH-related regulatory mechanisms in S. aureus, which are important for the defense under redox stress conditions. Application of the novel Brx-roGFP2 biosensor provides new insights on the impact of these systems on the BSH redox potential. These thiol switches of S. aureus function in protection against redox active desinfectants and antimicrobials, including HOCl, the AGXX® antimicrobial surface coating, allicin from garlic and the naphthoquinone lapachol. Thus, thiol switches could be novel drug targets for the development of alternative redox-based therapies to combat multi-drug resistant S. aureus isolates.
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Affiliation(s)
- Nico Linzner
- Freie Universität Berlin, Institute of Biology-Microbiology, Königin-Luise-Straße 12-16, D-14195Berlin, Germany
| | - Vu Van Loi
- Freie Universität Berlin, Institute of Biology-Microbiology, Königin-Luise-Straße 12-16, D-14195Berlin, Germany
| | - Verena Nadin Fritsch
- Freie Universität Berlin, Institute of Biology-Microbiology, Königin-Luise-Straße 12-16, D-14195Berlin, Germany
| | - Haike Antelmann
- Freie Universität Berlin, Institute of Biology-Microbiology, Königin-Luise-Straße 12-16, D-14195Berlin, Germany
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Abstract
The stereospecific 1,2-migration of boronate complexes is one of the most representative reactions in boron chemistry. This process has been used extensively to develop powerful methods for asymmetric synthesis, with applications spanning from pharmaceuticals to natural products. Typically, 1,2-migration of boronate complexes is driven by displacement of an α-leaving group, oxidation of an α-boryl radical, or electrophilic activation of an alkenyl boronate complex. The aim of this article is to summarize the recent advances in the rapidly expanding field of electrophile-induced stereospecific 1,2-migration of groups from boron to sp2 and sp3 carbon centers. It will be shown that three different conceptual approaches can be utilized to enable the 1,2-migration of boronate complexes: stereospecific Zweifel-type reactions, catalytic conjunctive coupling reactions, and transition metal-free sp2 -sp3 couplings. A discussion of the reaction scope, mechanistic insights, and synthetic applications of the work described is also presented.
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Affiliation(s)
- Hui Wang
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Changcheng Jing
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
| | - Adam Noble
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
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Vinogradova EV, Zhang X, Remillard D, Lazar DC, Suciu RM, Wang Y, Bianco G, Yamashita Y, Crowley VM, Schafroth MA, Yokoyama M, Konrad DB, Lum KM, Simon GM, Kemper EK, Lazear MR, Yin S, Blewett MM, Dix MM, Nguyen N, Shokhirev MN, Chin EN, Lairson LL, Melillo B, Schreiber SL, Forli S, Teijaro JR, Cravatt BF. An Activity-Guided Map of Electrophile-Cysteine Interactions in Primary Human T Cells. Cell 2020; 182:1009-1026.e29. [PMID: 32730809 DOI: 10.1016/j.cell.2020.07.001] [Citation(s) in RCA: 158] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 05/14/2020] [Accepted: 06/30/2020] [Indexed: 12/19/2022]
Abstract
Electrophilic compounds originating from nature or chemical synthesis have profound effects on immune cells. These compounds are thought to act by cysteine modification to alter the functions of immune-relevant proteins; however, our understanding of electrophile-sensitive cysteines in the human immune proteome remains limited. Here, we present a global map of cysteines in primary human T cells that are susceptible to covalent modification by electrophilic small molecules. More than 3,000 covalently liganded cysteines were found on functionally and structurally diverse proteins, including many that play fundamental roles in immunology. We further show that electrophilic compounds can impair T cell activation by distinct mechanisms involving the direct functional perturbation and/or degradation of proteins. Our findings reveal a rich content of ligandable cysteines in human T cells and point to electrophilic small molecules as a fertile source for chemical probes and ultimately therapeutics that modulate immunological processes and their associated disorders.
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Affiliation(s)
| | - Xiaoyu Zhang
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - David Remillard
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Daniel C Lazar
- Department of Immunology and Infectious Disease, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Radu M Suciu
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Yujia Wang
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Giulia Bianco
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Yu Yamashita
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA; Medicinal Chemistry Research Laboratories, New Drug Research Division, Otsuka Pharmaceutical Co., Ltd., 463-10 Kawauchi-cho, Tokushima 771-0192, Japan
| | - Vincent M Crowley
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Michael A Schafroth
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Minoru Yokoyama
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - David B Konrad
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kenneth M Lum
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Gabriel M Simon
- Vividion Therapeutics, 5820 Nancy Ridge Drive, San Diego, CA 92121, USA
| | - Esther K Kemper
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Michael R Lazear
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Sifei Yin
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Megan M Blewett
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Melissa M Dix
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Nhan Nguyen
- Department of Immunology and Infectious Disease, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Maxim N Shokhirev
- Razavi Newman Integrative Genomics and Bioinformatics Core, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Emily N Chin
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Luke L Lairson
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Bruno Melillo
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA; Chemical Biology and Therapeutics Science Program, Broad Institute, Cambridge, MA 02138, USA
| | - Stuart L Schreiber
- Chemical Biology and Therapeutics Science Program, Broad Institute, Cambridge, MA 02138, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Stefano Forli
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - John R Teijaro
- Department of Immunology and Infectious Disease, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Benjamin F Cravatt
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA.
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15
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Reichel M, Karaghiosoff K. Reagents for Selective Fluoromethylation: A Challenge in Organofluorine Chemistry. Angew Chem Int Ed Engl 2020; 59:12268-12281. [PMID: 32022357 PMCID: PMC7383490 DOI: 10.1002/anie.201913175] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/30/2020] [Indexed: 01/09/2023]
Abstract
The introduction of a monofluoromethyl moiety has undoubtedly become a very important area of research in recent years. Owing to the beneficial properties of organofluorine compounds, such as their metabolic stability, the incorporation of the CH2 F group as a bioisosteric substitute for various functional groups is an attractive strategy for the discovery of new pharmaceuticals. Furthermore, the monofluoromethyl unit is also widely used in agrochemistry, in pharmaceutical chemistry, and in fine chemicals. The problems associated with climate change and the growing need for environmentally friendly industrial processes mean that alternatives to the frequently used CFC and HFBC fluoromethylating agents (CH2 FCl and CH2 FBr) are urgently needed and also required by the Montreal Protocol. This has recently prompted many researchers to develop alternative fluoromethylation agents. This Minireview summarizes both the classical and new generation of fluoromethylating agents. Reagents that act via electrophilic, nucleophilic, and radical pathways are discussed, in addition to their precursors.
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Affiliation(s)
- Marco Reichel
- Department of ChemistryLudwig-Maximilian UniversityButenandstr. 5–1381377MunichGermany
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16
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Zhang J, Chen Q, Mayer RJ, Yang J, Ofial AR, Cheng J, Mayr H. Predicting Absolute Rate Constants for Huisgen Reactions of Unsaturated Iminium Ions with Diazoalkanes. Angew Chem Int Ed Engl 2020; 59:12527-12533. [PMID: 32259362 PMCID: PMC7383640 DOI: 10.1002/anie.202003029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Indexed: 12/22/2022]
Abstract
The kinetics and stereochemistry of the reactions of iminium ions derived from cinnamaldehydes and MacMillan's imidazolidinones with diphenyldiazomethane and aryldiazomethanes were investigated experimentally and with DFT calculations. The reactions of diphenyldiazomethane with iminium ions derived from MacMillan's second-generation catalysts gave 3-aryl-2,2-diphenylcyclopropanecarbaldehydes with yields >90 % and enantiomeric ratios of ≥90:10. Predominantly 2:1 products were obtained from the corresponding reactions with monoaryldiazomethanes. The measured rate constants are in good agreement with the rate constants derived from the one-center nucleophilicity parameters N and sN of diazomethanes and the one-center electrophilicity parameters E of iminium ions as well as with quantum chemically calculated activation energies.
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Affiliation(s)
- Jingjing Zhang
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua UniversityBeijing100084P. R. China
| | - Quan Chen
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MünchenGermany
| | - Robert J. Mayer
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MünchenGermany
| | - Jin‐Dong Yang
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua UniversityBeijing100084P. R. China
| | - Armin R. Ofial
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MünchenGermany
| | - Jin‐Pei Cheng
- Center of Basic Molecular Science (CBMS)Department of ChemistryTsinghua UniversityBeijing100084P. R. China
- State Key Laboratory of Elemento-organic ChemistryCollege of ChemistryNankai UniversityTianjin300071P. R. China
| | - Herbert Mayr
- Department ChemieLudwig-Maximilians-Universität MünchenButenandtstr. 5–1381377MünchenGermany
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Monte I, Kneeshaw S, Franco-Zorrilla JM, Chini A, Zamarreño AM, García-Mina JM, Solano R. An Ancient COI1-Independent Function for Reactive Electrophilic Oxylipins in Thermotolerance. Curr Biol 2020; 30:962-971.e3. [PMID: 32142692 DOI: 10.1016/j.cub.2020.01.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 12/26/2019] [Accepted: 01/08/2020] [Indexed: 01/05/2023]
Abstract
The jasmonate signaling pathway regulates development, growth, and defense responses in plants. Studies in the model eudicot, Arabidopsis thaliana, have identified the bioactive hormone (jasmonoyl-isoleucine [JA-Ile]) and its Coronatine Insensitive 1 (COI1)/Jasmonate-ZIM Domain (JAZ) co-receptor. In bryophytes, a conserved signaling pathway regulates similar responses but uses a different ligand, the JA-Ile precursor dinor-12-oxo-10,15(Z)-phytodienoic acid (dn-OPDA), to activate a conserved co-receptor. Jasmonate responses independent of JA-Ile and COI1, thought to be mediated by the cyclopentenone OPDA, have also been suggested, but experimental limitations in Arabidopsis have hindered attempts to uncouple OPDA and JA-Ile biosynthesis. Thus, a clear understanding of this pathway remains elusive. Here, we address the role of cyclopentenones in COI1-independent responses using the bryophyte Marchantia polymorpha, which is unable to synthesize JA-Ile but does accumulate OPDA and dn-OPDA. We demonstrate that OPDA and dn-OPDA activate a COI1-independent pathway that regulates plant thermotolerance genes, and consequently, treatment with these oxylipins protects plants against heat stress. Furthermore, we identify that these molecules signal through their electrophilic properties. By performing comparative analyses between M. polymorpha and two evolutionary distant species, A. thaliana and the charophyte alga Klebsormidium nitens, we demonstrate that this pathway is conserved in streptophyte plants and pre-dates the evolutionary appearance of the COI1-dependent jasmonate pathway, which later co-opted the pre-existing dn-OPDA as its ligand. Taken together, our data indicate that cyclopentenone-regulated COI1-independent signaling is an ancient conserved pathway, whose ancestral role was to protect plants against heat stress. This pathway was likely crucial for plants' successful land colonization and will be critical for adaption to current climate warming.
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Affiliation(s)
- Isabel Monte
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain
| | - Sophie Kneeshaw
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain
| | - Jose M Franco-Zorrilla
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain
| | - Andrea Chini
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain
| | - Angel M Zamarreño
- Department of Environmental Biology, University of Navarra, Navarra 31008, Spain
| | - Jose M García-Mina
- Department of Environmental Biology, University of Navarra, Navarra 31008, Spain
| | - Roberto Solano
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Madrid 28049, Spain.
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18
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Manda G, Rojo AI, Martínez-Klimova E, Pedraza-Chaverri J, Cuadrado A. Nordihydroguaiaretic Acid: From Herbal Medicine to Clinical Development for Cancer and Chronic Diseases. Front Pharmacol 2020; 11:151. [PMID: 32184727 PMCID: PMC7058590 DOI: 10.3389/fphar.2020.00151] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 02/05/2020] [Indexed: 12/11/2022] Open
Abstract
Nordihydroguaiaretic acid (NDGA) is a phenolic lignan obtained from Larrea tridentata, the creosote bush found in Mexico and USA deserts, that has been used in traditional medicine for the treatment of numerous diseases such as cancer, renal, cardiovascular, immunological, and neurological disorders, and even aging. NDGA presents two catechol rings that confer a very potent antioxidant activity by scavenging oxygen free radicals and this may explain part of its therapeutic action. Additional effects include inhibition of lipoxygenases (LOXs) and activation of signaling pathways that impinge on the transcription factor Nuclear Factor Erythroid 2-related Factor (NRF2). On the other hand, the oxidation of the catechols to the corresponding quinones my elicit alterations in proteins and DNA that raise safety concerns. This review describes the current knowledge on NDGA, its targets and side effects, and its synthetic analogs as promising therapeutic agents, highlighting their mechanism of action and clinical projection towards therapy of neurodegenerative, liver, and kidney disease, as well as cancer.
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Affiliation(s)
- Gina Manda
- Department Cellular and Molecular Medicine, Victor Babes National Institute of Pathology, Bucharest, Romania
| | - Ana I Rojo
- Department of Biochemistry, Faculty of Medicine, Autonomous University of Madrid, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Investigación Sanitaria la Paz (idiPAZ), Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC, Madrid, Spain
| | - Elena Martínez-Klimova
- Department of Biology, Faculty of Chemistry, National Autonomous University of Mexico (UNAM), Mexico City, Mexico
| | - José Pedraza-Chaverri
- Department of Biology, Faculty of Chemistry, National Autonomous University of Mexico (UNAM), Mexico City, Mexico
| | - Antonio Cuadrado
- Department Cellular and Molecular Medicine, Victor Babes National Institute of Pathology, Bucharest, Romania.,Department of Biochemistry, Faculty of Medicine, Autonomous University of Madrid, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Investigación Sanitaria la Paz (idiPAZ), Instituto de Investigaciones Biomédicas "Alberto Sols" UAM-CSIC, Madrid, Spain
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19
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Unoki T, Akiyama M, Kumagai Y. Nrf2 Activation and Its Coordination with the Protective Defense Systems in Response to Electrophilic Stress. Int J Mol Sci 2020; 21:E545. [PMID: 31952233 DOI: 10.3390/ijms21020545] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 01/11/2020] [Indexed: 12/18/2022] Open
Abstract
Molecular responses mediated by sensor proteins are important for biological defense against electrophilic stresses, such as xenobiotic electrophile exposure. NF-E2-related factor 2 (Nrf2) has an essential function as a master regulator of such cytoprotective molecular responses along with sensor protein Kelch-like ECH-associated protein 1. This review focuses on Nrf2 activation and its involvement with the protective defense systems under electrophilic stresses integrated with our recent findings that reactive sulfur species (RSS) mediate detoxification of electrophiles. The Nrf2 pathway does not function redundantly with the RSS-generating cystathionine γ-lyase pathway, and vice versa.
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20
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Collar AG, Trujillo C, Connon SJ. Highly Enantio- and Diastereoselective Catalytic Asymmetric Tamura Cycloaddition Reactions. Chemistry 2019; 25:7270-7274. [PMID: 31050071 DOI: 10.1002/chem.201900119] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Indexed: 12/22/2022]
Abstract
The first broad-scope catalytic asymmetric Tamura cycloaddition reactions are reported. Under the influence of anion-binding bifunctional catalysis a wide range of α,β-unsaturated N-trityl imines undergo reactions with enolisable anhydrides to form highly synthetically useful α-tetralone structures with excellent enantio- and -diastereocontrol. In stark contrast to the previous literature benchmarks, doubly activated or highly electron deficient alkenes are not required. A facile two-step, high yielding sequence can convert the cycloadducts to α-haloketones (challenging to generate catalytically by other means) with the net formation of two new C-C bonds and three new contiguous stereocentres with exquisite stereocontrol. A DFT study has provided insight into the catalyst mode of action and the origins of the observed enantiocontrol.
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Affiliation(s)
- Aarón Gutiérrez Collar
- School of Chemistry Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin, 2, Ireland
| | - Cristina Trujillo
- School of Chemistry Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin, 2, Ireland
| | - Stephen J Connon
- School of Chemistry Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin, 2, Ireland
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21
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Carlsson H, Rappaport SM, Törnqvist M. Protein Adductomics: Methodologies for Untargeted Screening of Adducts to Serum Albumin and Hemoglobin in Human Blood Samples. High Throughput 2019; 8:E6. [PMID: 30857166 PMCID: PMC6473736 DOI: 10.3390/ht8010006] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 11/16/2022] Open
Abstract
The reaction products of electrophiles in vivo can be measured as adducts to the abundant proteins, hemoglobin (Hb), and human serum albumin (HSA), in human blood samples. During the last decade, methods for untargeted screening of such adducts, called "adductomics", have used liquid chromatography-mass spectrometry to detect large numbers of previously unknown Hb and HSA adducts. This review presents methodologies that were developed and used in our laboratories for Hb and HSA adductomics, respectively. We discuss critical aspects regarding choice of target protein, sample preparation, mass spectrometry, data evaluation, and strategies for identification of detected unknown adducts. With this review we give an overview of these two methodologies used for protein adductomics and the precursor electrophiles that have been elucidated from the adducts.
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Affiliation(s)
- Henrik Carlsson
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA 94720, USA.
| | - Stephen M Rappaport
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA 94720, USA.
| | - Margareta Törnqvist
- Department of Environmental Science and Analytical Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.
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22
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Liang HC, Liu YC, Chen H, Ku MC, Do QT, Wang CY, Tzeng SF, Chen SH. In Situ Click Reaction Coupled with Quantitative Proteomics for Identifying Protein Targets of Catechol Estrogens. J Proteome Res 2018; 17:2590-2599. [PMID: 29897771 DOI: 10.1021/acs.jproteome.8b00021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Catechol estrogens (CEs) are metabolic electrophiles that actively undergo covalent interaction with cellular proteins, influencing molecular function. There is no feasible method to identify their binders in a living system. Herein, we developed a click chemistry-based approach using ethinylestradiol (EE2) as the precursor probe coupled with quantitative proteomics to identify protein targets of CEs and classify their binding strengths. Using in situ metabolic conversion and click reaction in liver microsomes, CEs-protein complex was captured by the probe, digested by trypsin, stable isotope labeled via reductive amination, and analyzed by liquid chromatography-mass spectrometry (LC-MS). A total of 334 liver proteins were repeatedly identified ( n ≥ 2); 274 identified proteins were classified as strong binders based on precursor mass mapping. The binding strength was further scaled by D/H ratio (activity probe/solvent): 259 strong binders had D/H > 5.25; 46 weak binders had 5.25 > D/H > 1; 5 nonspecific binders (keratins) had D/H < 1. These results were confirmed using spiked covalent control (strong binder) and noncovalent control (weak binder), as well as in vitro testing of cytochrome c (D/H = 5.9), which showed covalent conjugation with CEs. Many identified strong binders, such as glutathione transferase, catechol-O-methyl transferase, superoxide dismutase, catalase, glutathione peroxidase, and cytochrome c, are involved in cellular redox processes or detoxification activities. CE conjugation was shown to suppress the superoxide oxidase activity of cytochrome c, suggesting that CEs modification may alter the redox action of cellular proteins. Due to structural similarity and inert alkyne group, EE2 probe is very likely to capture protein targets of CEs in general. Thus, this strategy can be adopted to explore the biological impact of CEs modification in living systems.
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Abstract
My chemical training provided a somewhat different perspective of biolo-gical problems, in the problem itself and approaches to its solution. I was fortunate to have in my laboratory postdocs and students who shared this perspective and used appropriate tools to address problems in amphetamine pharmacology and air pollution toxicology. These apparently disparate areas of research shared two chemical reactions: prooxidant-based generation of reactive oxygen and formation of covalent bonds between electrophiles and biological nucleophiles. This article is an attempt to summarize that research and to identify those individuals who made the contributions.
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Affiliation(s)
- Arthur K Cho
- Department of Molecular and Medical Pharmacology and Department of Environmental Health Sciences, UCLA Center for the Health Sciences, University of California, Los Angeles, California 90095, USA;
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24
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Vomund S, Schäfer A, Parnham MJ, Brüne B, von Knethen A. Nrf2, the Master Regulator of Anti-Oxidative Responses. Int J Mol Sci 2017; 18:ijms18122772. [PMID: 29261130 PMCID: PMC5751370 DOI: 10.3390/ijms18122772] [Citation(s) in RCA: 425] [Impact Index Per Article: 60.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 12/11/2017] [Accepted: 12/16/2017] [Indexed: 12/15/2022] Open
Abstract
Tight regulation of inflammation is very important to guarantee a balanced immune response without developing chronic inflammation. One of the major mediators of the resolution of inflammation is the transcription factor: the nuclear factor erythroid 2-like 2 (Nrf2). Stabilized following oxidative stress, Nrf2 induces the expression of antioxidants as well as cytoprotective genes, which provoke an anti-inflammatory expression profile, and is crucial for the initiation of healing. In view of this fundamental modulatory role, it is clear that both hyper- or hypoactivation of Nrf2 contribute to the onset of chronic diseases. Understanding the tight regulation of Nrf2 expression/activation and its interaction with signaling pathways, known to affect inflammatory processes, will facilitate development of therapeutic approaches to prevent Nrf2 dysregulation and ameliorate chronic inflammatory diseases. We discuss in this review the principle mechanisms of Nrf2 regulation with a focus on inflammation and autophagy, extending the role of dysregulated Nrf2 to chronic diseases and tumor development.
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Affiliation(s)
- Sandra Vomund
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Project Group Translational Medicine & Pharmacology TMP, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
| | - Anne Schäfer
- Institute of Biochemistry I-Pathobiochemistry, Faculty of Medicine, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
| | - Michael J Parnham
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Project Group Translational Medicine & Pharmacology TMP, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
| | - Bernhard Brüne
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Project Group Translational Medicine & Pharmacology TMP, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
- Institute of Biochemistry I-Pathobiochemistry, Faculty of Medicine, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
| | - Andreas von Knethen
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Project Group Translational Medicine & Pharmacology TMP, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
- Institute of Biochemistry I-Pathobiochemistry, Faculty of Medicine, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
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25
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Frogley BJ, Perera LC, Wright LJ. Syntheses of Amino-Substituted Iridabenzofurans and Subsequent Selective N-Functionalisation. Chemistry 2017; 24:4304-4309. [PMID: 29114951 DOI: 10.1002/chem.201704677] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 11/07/2017] [Indexed: 11/12/2022]
Abstract
The first examples of amino-substituted fused-ring metallabenzenes, the cationic iridabenzofuran [Ir(C7 H4 O{NH2 -2}{OMe-7})(CO)(PPh3 )2 ][O3 SCF3 ] (5) and neutral analogue Ir(C7 H4 {NH2 -2}{OMe-7})Cl(PPh3 )2 (6), can be prepared by reduction of the corresponding nitro-substituted iridabenzofurans with zinc and concentrated hydrochloric acid. N-functionalised derivatives of 5 and 6 are formed through alkylation, sulfonylation or acylation. Thus, consecutive treatments with methyl triflate and base gives the corresponding trimethylammonium-substituted iridabenzofurans while sulfonamide derivatives are formed with p-toluenesulfonyl chloride. N-Acylation of 5 or 6 with acid chlorides, however, selectively form either amide or imide products depending on the charge on the metal and the steric size of the acid chloride. Cationic 5 gives amide substituted products regardless of the conditions whereas neutral 6 rapidly undergoes di-N-acylation with excess benzoyl chloride under mild conditions to give the imide-substituted product Ir(C7 H4 O{N[C(O)Ph]2 -2}{OMe-7})Cl(PPh3 )2 (13). Selective mono-acylation of 6 can be achieved with one equivalent of benzoyl chloride or with excess of the sterically congested pivaloyl chloride.
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Affiliation(s)
- Benjamin J Frogley
- School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Lakshika C Perera
- School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - L James Wright
- School of Chemical Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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Haydl AM, Breit B, Liang T, Krische MJ. Alkynes as Electrophilic or Nucleophilic Allylmetal Precursors in Transition-Metal Catalysis. Angew Chem Int Ed Engl 2017; 56:11312-11325. [PMID: 28605083 PMCID: PMC5637541 DOI: 10.1002/anie.201704248] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Indexed: 11/06/2022]
Abstract
Diverse late transition metal catalysts convert terminal or internal alkynes into transient allylmetal species that display electrophilic or nucleophilic properties. Whereas classical methods for the generation of allylmetal species often form stoichiometric by-products, the recent use of alkynes as allylmetal precursors enables completely atom-efficient catalytic processes to be carried out, including enantioselective transformations.
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Affiliation(s)
- Alexander M Haydl
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104, Freiburg i. Brsg., Germany
| | - Bernhard Breit
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104, Freiburg i. Brsg., Germany
| | - Tao Liang
- Department of Chemistry, University of Texas at Austin, 105 E 24th St. Welch Hall, A5300, Austin, TX, 78712-1167, USA
| | - Michael J Krische
- Department of Chemistry, University of Texas at Austin, 105 E 24th St. Welch Hall, A5300, Austin, TX, 78712-1167, USA
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Moustafa MS, Al-Mousawi SM, El-Seedi HR, Elnagdi MH. Chemistry of Heterocyclic Five and Six Membered Enamino Nitriles and Enamino Esters. Mini Rev Med Chem 2016; 18:992-1007. [PMID: 27903227 DOI: 10.2174/1389557516666161130100610] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 09/11/2016] [Accepted: 10/13/2016] [Indexed: 11/22/2022]
Abstract
Progress in the chemistry of cyclic enamino-nitriles based on the advanced synthetic methodologies is reported. Due to the recent accomplishment, it becomes possible to reactivate these molecules toward electrophiles, nucleophiles and as electron rich dienes in 2+3 dipolar additions and in 4+2 cycloadditions reactions. Synthesizing the poly functionalized 4H-pyrans and their fused derivatives is a fascinating field with a multitude of biological implications such as antitumor, cardiotonic, hepatoprotective, antihypertensive, antibronchitis, as well antifungal activity. This work was conducted with particular emphasis on reviewing the work done on the cyclic enamines since 1990 up till now in order to highlight in more details the synthetic pathways, interactions and the biological activities, Furthermore; we referred to the recent original data of our group contributions within this field.
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Affiliation(s)
- Moustafa Sherief Moustafa
- Department of Chemistry, Faculty of Science; University of Kuwait: Safat; 13060, P.O. Box 5969, Kuwait
| | - Saleh Mohammed Al-Mousawi
- Department of Chemistry, Faculty of Science; University of Kuwait: Safat; 13060, P.O. Box 5969, Kuwait
| | - Hesham R El-Seedi
- Division of Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, Box 574, SE-751 23, Uppsala, Sweden.,Research Institute of Chemistry, International Centre for Chemical and Biological Sciences (ICCBS), University of Karachi, Karachi-75270, Pakistan.,Chemistry Department, Faculty of Science, Menoufia University, Menoufia, Egypt
| | - Mohamed Hilmy Elnagdi
- Department of Chemistry, Faculty of Science, Cairo University, P.O. Box 12613, Giza, Egypt
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Abstract
Pharmacological activation of the transcription factor nuclear factor-erythroid derived 2-like 2 (NRF2), the key regulator of the cellular antioxidant response, has been recognized as a feasible strategy to reduce oxidative/electrophilic stress and prevent carcinogenesis or other chronic illnesses, such as diabetes and chronic kidney disease. In contrast, due to the discovery of the "dark side" of NRF2, where prolonged activation of NRF2 causes tissue damage, cancer progression, or chemoresistance, efforts have been devoted to identify inhibitors. Currently, only one NRF2 activator has been approved for use in the clinic, while no specific NRF2 inhibitors have been discovered. Future development of NRF2-targeted therapeutics should be based on our current understanding of the regulatory mechanisms of this protein. In addition to the KEAP1-dependent mechanisms, the recent discovery of other pathways involved in the degradation of NRF2 have opened up new possibilities for the development of safe and specific therapeutics. Here, we review available and putative NRF2-targeted therapeutics and discuss their modes of action as well as their potential for disease prevention and treatment.
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Affiliation(s)
- Montserrat Rojo de la Vega
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ, USA, 85721
| | - Matthew Dodson
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ, USA, 85721
| | - Eli Chapman
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ, USA, 85721
| | - Donna D Zhang
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, AZ, USA, 85721.,Arizona Cancer Center, University of Arizona, Tucson, AZ, USA, 85724
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Deeming AS, Russell CJ, Willis MC. Palladium(II)-Catalyzed Synthesis of Sulfinates from Boronic Acids and DABSO: A Redox-Neutral, Phosphine-Free Transformation. Angew Chem Int Ed Engl 2016; 55:747-50. [PMID: 26596861 PMCID: PMC4832823 DOI: 10.1002/anie.201508370] [Citation(s) in RCA: 197] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Indexed: 12/15/2022]
Abstract
A redox-neutral palladium(II)-catalyzed conversion of aryl, heteroaryl, and alkenyl boronic acids into sulfinate intermediates, and onwards to sulfones and sulfonamides, has been realized. A simple Pd(OAc)2 catalyst, in combination with the sulfur dioxide surrogate 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) (DABSO), is sufficient to achieve rapid and high-yielding conversion of the boronic acids into the corresponding sulfinates. Addition of C- or N-based electrophiles then allows conversion into sulfones and sulfonamides, respectively, in a one-pot, two-step process.
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Affiliation(s)
- Alex S Deeming
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA (UK) http://mcwillis.chem.ox.ac.uk/MCW/Home.html
| | - Claire J Russell
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire, RG42 6EY (UK)
| | - Michael C Willis
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA (UK) http://mcwillis.chem.ox.ac.uk/MCW/Home.html.
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Abstract
This mini-review presents the authors' vision on the current status and future trends in the development of neuroprotective agents working via activation of nuclear factor erythroid 2-related factor 2 (Nrf2), and in particular, via disruption of Nrf2-Keap1 interaction. There are two opposite "chemical" mechanisms underlying such activation: the first one is a non-specific covalent modification of Keap1 thiols, resulting in side effects of varied severity, and the second one is the shift of the Nrf2-Kelch-like ECH associated protein-1 (Keap1) binding equilibrium in the presence of a competitive and chemically benign displacement agent. At this point, no displacement activators exhibit sufficient biological activity in comparison with common Nrf2 activators working via Keap1 thiol modification. Hence, the hope in therapeutics is now linked to the FDA approved dimethylfumarate, whose derivative, monomethylfumarate, as we demonstrated recently, is much less toxic but equally biologically potent and an ideal candidate for clinical trials right now. A newly emerging player is a nuclear inhibitor of Nrf2, BTB domain and CNC homolog 1 (Bach1). The commercially developed Bach1 inhibitors are currently under investigation in our laboratory showing promising results. In our viewpoint, the perfect future drug will present the combination of a displacement activator and Bach1 inhibitor to insure safety and efficiency of Nrf2 activation.
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Affiliation(s)
- Irina G Gazaryan
- Department of Cell Biology and Anatomy, School of Medicine, New York Medical College, Valhalla, NY, USA; and Department of Chemistry and Physical Sciences, Dyson College, Pace University, Pleasantville, NY, USA
| | - Bobby Thomas
- Departments of Pharmacology, Toxicology and Neurology, Medical College of Georgia, Augusta University, Augusta, GA, USA
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Pinto A, Tamborini L, Cullia G, Conti P, De Micheli C. Inspired by Nature: The 3-Halo-4,5-dihydroisoxazole Moiety as a Novel Molecular Warhead for the Design of Covalent Inhibitors. ChemMedChem 2015; 11:10-4. [PMID: 26607551 DOI: 10.1002/cmdc.201500496] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Indexed: 11/10/2022]
Abstract
Over the past few decades, there has been an increasing interest in the development of covalent enzyme inhibitors. As it was recently re-emphasized, the selective, covalent binding of a drug to the desired target can increase efficiency and lower the inhibitor concentration required to achieve a therapeutic effect. In this context, the naturally occurring antibiotic acivicin, and in particular its 3-chloro-4,5-dihydroisoxazole scaffold, has provided a wealth of inspiration to medicinal chemists and chemical biologists alike. In this Concept, to underline the great potentiality that the 3-halo-4,5-dihydroisoxazole warhead has in drug discovery, we present a number of examples, grouped by their potential biological activity and targets, in which this scaffold has been fruitfully used to develop novel biologically active compounds. Through these examples, we show that the 3-halo-4,5-dihydroisoxazole moiety represents an outstanding warhead with high potential for the design of novel covalent enzyme inhibitors.
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Affiliation(s)
- Andrea Pinto
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Via Mangiagalli, 25, 20133, Milano, Italy
| | - Lucia Tamborini
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Via Mangiagalli, 25, 20133, Milano, Italy
| | - Gregorio Cullia
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Via Mangiagalli, 25, 20133, Milano, Italy
| | - Paola Conti
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Via Mangiagalli, 25, 20133, Milano, Italy
| | - Carlo De Micheli
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Via Mangiagalli, 25, 20133, Milano, Italy.
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Eiguren-Fernandez A, Di Stefano E, Schmitz DA, Guarieiro ALN, Salinas EM, Nasser E, Froines JR, Cho AK. Chemical reactivities of ambient air samples in three Southern California communities. J Air Waste Manag Assoc 2015; 65:270-7. [PMID: 25947123 PMCID: PMC4425251 DOI: 10.1080/10962247.2014.988307] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
UNLABELLED The potential adverse health effects of PM2.5 (particulate matter with an aerodynamic diameter<2.5 μm) and vapor samples from three communities that neighbor railyards, Commerce (CM), Long Beach (LB), and San Bernardino (SB), were assessed by determination of chemical reactivities attributed to the induction of oxidative stress by air pollutants. The assays used were dithiothreitol (DTT)- and dihydrobenzoic acid (DHBA)-based procedures for prooxidant content and a glyceraldehyde-3-phosphate dehydrogenase (GAPDH) assay for electrophiles. Prooxidants and electrophiles have been proposed as the reactive chemical species responsible for the induction of oxidative stress by air pollution mixtures. The PM2.5 samples from CM and LB sites showed seasonal differences in reactivities, with higher levels in the winter, whereas the SB sample differences were reversed. The reactivities in the vapor samples were all very similar, except for the summer SB samples, which contained higher levels of both prooxidants and electrophiles. The results suggest that the observed reactivities reflect general geographical differences rather than direct effects of the railyards. Distributional differences in reactivities were also observed, with PM2.5 fractions containing most of the prooxidants (74-81%) and the vapor phase most of the electrophiles (82-96%). The high levels of the vapor-phase electrophiles and their potential for adverse biological effects point out the importance of the vapor phase in assessing the potential health effects of ambient air. IMPLICATIONS PM2.5 and its corresponding vapor phase, containing semivolatile organics, were collected in three communities in the Los Angeles Basin and examined with toxicologically relevant chemical assays. The PM2.5 phase contained most of the prooxidants and the vapor phase contained most of the electrophiles, whose content was highest in summer samples from a receptor site that reflected greater photochemical processing of the air parcel during its transport. As electrophiles initiate both adverse and adaptive responses to foreign substances by biological systems, their presence in the vapor phase emphasizes the importance of this phase in the overall health effects of ambient air.
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Affiliation(s)
- Arantza Eiguren-Fernandez
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
| | - Emma Di Stefano
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
| | - Debra A. Schmitz
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
| | - Aline Lefol Nani Guarieiro
- Southern California Particle Center
- Universidade Federal da Bahia, Instituto de Química, 40170290, Salvador-BA/Brasil
| | - Erika M. Salinas
- Southern California Particle Center
- División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana, Azcapotzalco, Mexico
| | - Elina Nasser
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
| | - John R. Froines
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
| | - Arthur K. Cho
- Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772
- Southern California Particle Center
- Corresponding author: Arthur K. Cho, Ph.D., CHS 21-297 Department of Environmental Health Sciences, School of Public Health, University of California Los Angeles, CA 90095-1772, UCLA, Phone: 310-825-6567,
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Beaud R, Guillot R, Kouklovsky C, Vincent G. Regioselective hydroarylation reactions of C3 electrophilic N-acetylindoles activated by FeCl3: an entry to 3-(hetero)arylindolines. Chemistry 2014; 20:7492-500. [PMID: 24828464 DOI: 10.1002/chem.201400284] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Indexed: 11/06/2022]
Abstract
A method for the direct and rare umpolung of the 3 position of indoles is reported. The activation of N-acetylindole with iron(III) chloride allows the C-H addition of aromatic and heteroaromatic substrates to the C2=C3 double bond of the indole nucleus to generate a quaternary center at C3 and leads regioselectively to 3-arylindolines. Optimization, scope (50 examples), practicability (gram scale, air atmosphere, room temperature), and mechanistic insights of this process are presented. Synthetic transformations of the indoline products into drug-like compounds are also described.
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Affiliation(s)
- Rodolphe Beaud
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Equipe Méthodologie, Synthèse et Molécules Thérapeutiques, Univ Paris Sud and CNRS, 15 rue Georges Clemenceau, Bat 410, 91406, Orsay (France), Fax: (+33) 1-69-15-46-79
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Abstract
Covalent inhibitors of lymphoid tyrosine phosphatase (LYP) were identified from a screen of the NIH Molecular Libraries Small Molecules Repository (MLSMR). Both of the two lead compounds identified have phosphotyrosine-mimetic benzoic acid moieties as well as electrophilic acrylonitrile groups. Inhibition kinetics of both compounds are consistent with covalent modification of the enzyme, with nanomolar KI and reciprocal millisecond kinact values, representing the best efficiency ratios (kinact /KI ) among currently reported covalent LYP inhibitors. Covalent inhibitors can provide longer efficacy and better selectivity than more conventional noncovalent inhibitors, and these lead compounds are an important step toward the development of protein tyrosine phosphatase (PTP)-targeted covalent therapeutic compounds.
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Affiliation(s)
- Vanessa F. Ahmed
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Nunzio Bottini
- Division of Cellular Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037, USA
| | - Amy M. Barrios
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, UT 84112, USA
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Meyer D, Herrfurth C, Brodhun F, Feussner I. Degradation of lipoxygenase-derived oxylipins by glyoxysomes from sunflower and cucumber cotyledons. BMC Plant Biol 2013; 13:177. [PMID: 24207097 PMCID: PMC3831820 DOI: 10.1186/1471-2229-13-177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 11/07/2013] [Indexed: 05/17/2023]
Abstract
BACKGROUND Oilseed germination is characterized by the degradation of storage lipids. It may proceed either via the direct action of a triacylglycerol lipase, or in certain plant species via a specific lipid body 13-lipoxygenase. For the involvement of a lipoxygenase previous results suggested that the hydroxy- or oxo-group that is being introduced into the fatty acid backbone by this lipoxygenase forms a barrier to continuous β-oxidation. RESULTS This study shows however that a complete degradation of oxygenated fatty acids is possible by isolated cucumber and sunflower glyoxysomes. Interestingly, degradation is accompanied by the formation of saturated short chain acyl-CoAs with chain length between 4 and 12 carbon atoms lacking the hydroxy- or oxo-diene system of the oxygenated fatty acid substrate. The presence of these CoA esters suggests the involvement of a specific reduction of the diene system at a chain length of 12 carbon atoms including conversion of the hydroxy-group at C7. CONCLUSIONS To our knowledge this metabolic pathway has not been described for the degradation of polyunsaturated fatty acids so far. It may represent a new principle to degrade oxygenated fatty acid derivatives formed by lipoxygenases or chemical oxidation initiated by reactive oxygen species.
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Affiliation(s)
- Danilo Meyer
- Georg-August-University, Albrecht-von-Haller Institute for Plant Sciences, Department for Plant Biochemistry, Justus-von-Liebig-Weg 11, Göttingen D-37075, Germany
| | - Cornelia Herrfurth
- Georg-August-University, Albrecht-von-Haller Institute for Plant Sciences, Department for Plant Biochemistry, Justus-von-Liebig-Weg 11, Göttingen D-37075, Germany
| | - Florian Brodhun
- Georg-August-University, Albrecht-von-Haller Institute for Plant Sciences, Department for Plant Biochemistry, Justus-von-Liebig-Weg 11, Göttingen D-37075, Germany
| | - Ivo Feussner
- Georg-August-University, Albrecht-von-Haller Institute for Plant Sciences, Department for Plant Biochemistry, Justus-von-Liebig-Weg 11, Göttingen D-37075, Germany
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36
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Abstract
Thiol-mediated processes play a key role to induce or inhibit inflammation proteins. Tailoring the reactivity of electrophiles can enhance the selectivity to address only certain surface cysteines. Fourteen 2',3,4,4'-tetramethoxychalcones with different α-X substituents (X=H, F, Cl, Br, I, CN, Me, p-NO2-C6H4, Ph, p-OMe-C6H4, NO2, CF3, COOEt, COOH) were synthesized, containing the potentially electrophilic α,β-unsaturated carbonyl unit. The assessment of their reactivity as electrophiles in thia-Michael additions with cysteamine shows a change in the reactivity of more than six orders of magnitude. Moreover, a clear correlation between their reactivity and an influence on the inflammation proteins heme oxygenase-1 (HO-1) and the inducible NO synthase (iNOS) is demonstrated. As the biologically most active compound, the α-CF3 -chalcone is shown to inhibit the NO production in RAW264.7 mouse macrophages in the nanomolar range.
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Affiliation(s)
- Nafisah Al-Rifai
- Institute of Organic Chemistry, University of Regensburg, Universitätsstraße 31, 93053 Regensburg (Germany)
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Chen RC, Naiyanetr P, Shu SA, Wang J, Yang GX, Thomas PK, Guggenheim KC, Butler JD, Bowlus C, Tao MH, Kurth MJ, Ansari AA, Kaplan M, Coppel RL, Lleo A, Gershwin ME, Leung PS. Antimitochondrial antibody heterogeneity and the xenobiotic etiology of primary biliary cirrhosis. Hepatology 2013; 57. [PMID: 23184636 PMCID: PMC3601563 DOI: 10.1002/hep.26157] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
UNLABELLED Antimitochondrial antibodies (AMAs) directed against the lipoyl domain of the E2 subunit of pyruvate dehydrogenase (PDC-E2) are detected in 95% of patients with primary biliary cirrhosis (PBC) and are present before the onset of clinical disease. The recent demonstration that AMAs recognize xenobiotic modified PDC-E2 with higher titers than native PDC-E2 raises the possibility that the earliest events involved in loss of tolerance are related to xenobiotic modification. We hypothesized that reactivity to such xenobiotics would be predominantly immunoglobulin M (IgM) and using sera from a large cohort of PBC patients and controls (n = 516), we examined in detail sera reactivity against either 6,8-bis(acetylthio) octanoic acid (SAc)-conjugated bovine serum albumin (BSA), recombinant PDC-E2 (rPDC-E2) or BSA alone. Further, we also defined the relative specificity to the SAc moiety using inhibition enzyme-linked immunosorbent assay (ELISA); SAc conjugate and rPDC-E2-specific affinity-purified antibodies were also examined for antigen specificity, isotype, and crossreactivity. Reactivity to SAc conjugates is predominantly IgM; such reactivity reflects a footprint of previous xenobiotic exposure. Indeed, this observation is supported by both direct binding, crossreactivity, and inhibition studies. In both early and late-stage PBC, the predominant Ig isotype to SAc is IgM, with titers higher with advanced stage disease. We also note that there was a higher level of IgM reactivity to SAc than to rPDC-E2 in early-stage versus late-stage PBC. Interestingly, this finding is particularly significant in light of the structural similarity between SAc and the reduced form of lipoic acid, a step which is similar to the normal physiological oxidation of lipoic acid. CONCLUSION Specific modifications of the disulfide bond within the lipoic-acid-conjugated PDC-E2 moiety, i.e., by an electrophilic agent renders PDC-E2 immunogenic in a genetically susceptible host.
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Affiliation(s)
- Richy C.Y. Chen
- Division of Rheumatology/Allergy and Clinical Immunology, University of California, Davis, CA 95616
| | - Phornnop Naiyanetr
- Division of Rheumatology/Allergy and Clinical Immunology, University of California, Davis, CA 95616,Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Shang-An Shu
- Division of Rheumatology/Allergy and Clinical Immunology, University of California, Davis, CA 95616
| | - Jinjun Wang
- Division of Rheumatology/Allergy and Clinical Immunology, University of California, Davis, CA 95616
| | - Guo-Xiang Yang
- Division of Rheumatology/Allergy and Clinical Immunology, University of California, Davis, CA 95616
| | - P. Kenny Thomas
- Division of Rheumatology/Allergy and Clinical Immunology, University of California, Davis, CA 95616
| | | | | | | | - Mi-Hua Tao
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Mark J. Kurth
- Department of Chemistry, University of California, Davis, CA 95616
| | - Aftab A. Ansari
- Department of Pathology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Marshall Kaplan
- Department of Medicine, Division of Gastroenterology, New England Medical Center, Tufts University School of Medicine, Boston, MA 02111
| | - Ross L. Coppel
- Department of Medical Microbiology, Monash University, Melbourne, Australia
| | - Ana Lleo
- Center for Autoimmune Liver Diseases, Humanitas Clinical and Research Center, Rozzano (Milan), Italy
| | - M. Eric Gershwin
- Division of Rheumatology/Allergy and Clinical Immunology, University of California, Davis, CA 95616
| | - Patrick S.C. Leung
- Division of Rheumatology/Allergy and Clinical Immunology, University of California, Davis, CA 95616
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Staimer N, Nguyen TB, Nizkorodov SA, Delfino RJ. Glutathione peroxidase inhibitory assay for electrophilic pollutants in diesel exhaust and tobacco smoke. Anal Bioanal Chem 2012; 403:431-41. [PMID: 22349402 PMCID: PMC3328416 DOI: 10.1007/s00216-012-5823-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 01/30/2012] [Accepted: 02/01/2012] [Indexed: 01/23/2023]
Abstract
We developed a rapid kinetic bioassay demonstrating the inhibition of glutathione peroxidase 1 (GPx-1) by organic electrophilic pollutants, such as acrolein, crotonaldehyde, and p-benzoquinone, that are frequently found as components of tobacco smoke, diesel exhaust, and other combustion sources. In a complementary approach, we applied a high-resolution proton-transfer reaction time-of-flight mass spectrometer to monitor in real-time the generation of electrophilic volatile carbonyls in cigarette smoke. The new bioassay uses the important antioxidant selenoenzyme GPx-1, immobilized to 96-well microtiter plates, as a probe. The selenocysteine bearing subunits of the enzyme's catalytic site are viewed as cysteine analogues and are vulnerable to electrophilic attack by compounds with conjugated carbonyl systems. The immobilization of GPx-1 to microtiter plate wells enabled facile removal of excess reactive inhibitory compounds after incubation with electrophilic chemicals or aqueous extracts of air samples derived from different sources. The inhibitory response of cigarette smoke and diesel exhaust particle extracts were compared with chemical standards of a group of electrophilic carbonyls and the arylating p-benzoquinone. GPx-1 activity was directly inactivated by millimolar concentrations of highly reactive electrophilic chemicals (including acrolein, glyoxal, methylglyoxal, and p-benzoquinone) and extracts of diesel and cigarette smoke. We conclude that the potential of air pollutant components to generate oxidative stress may be, in part, a result of electrophile-derived covalent modifications of enzymes involved in the cytosolic antioxidant defense.
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Affiliation(s)
- Norbert Staimer
- Department of Epidemiology, School of Medicine, University of California, Irvine, CA 92697, USA.
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Smith K, El-Hiti GA, Hegazy AS, Kariuki B. A simple and convenient one-pot synthesis of substituted isoindolin-1-ones via lithiation, substitution and cyclization of N'-benzyl-N,N-dimethylureas. Beilstein J Org Chem 2011; 7:1219-27. [PMID: 21977206 PMCID: PMC3182431 DOI: 10.3762/bjoc.7.142] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 06/06/2011] [Indexed: 11/23/2022] Open
Abstract
Lithiation of N'-benzyl-N,N-dimethylurea and its substituted derivatives with t-BuLi (3.3 equiv) in anhydrous THF at 0 °C followed by reaction with various electrophiles afforded a range of 3-substituted isoindolin-1-ones in high yields.
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Affiliation(s)
- Keith Smith
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK, ; Tel: +44(0)2920870600
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40
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Abstract
This review begins with the premise that an organism's life span is determined by the balance between two countervailing forces: (i) the sum of destabilizing effects and (ii) the sum of protective longevity-assurance processes. Against this backdrop, the role of electrophiles is discussed, both as destabilizing factors and as signals that induce protective responses. Because most biological macromolecules contain nucleophilic centers, electrophiles are particularly reactive and toxic in a biological context. The majority of cellular electrophiles are generated from polyunsaturated fatty acids by a peroxidation chain reaction that is readily triggered by oxygen-centered radicals, but propagates without further input of reactive oxygen species (ROS). Thus, the formation of lipid-derived electrophiles such as 4-hydroxynon-2-enal (4-HNE) is proposed to be relatively insensitive to the level of initiating ROS, but to depend mainly on the availability of peroxidation-susceptible fatty acids. This is consistent with numerous observations that life span is inversely correlated to membrane peroxidizability, and with the hypothesis that 4-HNE may constitute the mechanistic link between high susceptibility of membrane lipids to peroxidation and shortened life span. Experimental interventions that directly alter membrane composition (and thus their peroxidizability) or modulate 4-HNE levels have the expected effects on life span, establishing that the connection is not only correlative but causal. Specific molecular mechanisms are considered, by which 4-HNE could (i) destabilize biological systems via nontargeted reactions with cellular macromolecules and (ii) modulate signaling pathways that control longevity-assurance mechanisms.
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Affiliation(s)
- Piotr Zimniak
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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41
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Khoo NK, Rudolph V, Cole MP, Golin-Bisello F, Schopfer FJ, Woodcock SR, Batthyany C, Freeman BA. Activation of vascular endothelial nitric oxide synthase and heme oxygenase-1 expression by electrophilic nitro-fatty acids. Free Radic Biol Med 2010; 48:230-9. [PMID: 19857569 PMCID: PMC2818734 DOI: 10.1016/j.freeradbiomed.2009.10.046] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 10/16/2009] [Accepted: 10/20/2009] [Indexed: 10/20/2022]
Abstract
Reactive oxygen species mediate a decrease in nitric oxide (NO) bioavailability and endothelial dysfunction, with secondary oxidized and nitrated by-products of these reactions contributing to the pathogenesis of numerous vascular diseases. While oxidized lipids and lipoproteins exacerbate inflammatory reactions in the vasculature, in stark contrast the nitration of polyunsaturated fatty acids and complex lipids yields electrophilic products that exhibit pluripotent anti-inflammatory signaling capabilities acting via both cGMP-dependent and -independent mechanisms. Herein we report that nitro-oleic acid (OA-NO(2)) treatment increases expression of endothelial nitric oxide synthase (eNOS) and heme oxygenase 1 (HO-1) in the vasculature, thus transducing vascular protective effects associated with enhanced NO production. Administration of OA-NO(2) via osmotic pump results in a significant increase in eNOS and HO-1 mRNA in mouse aortas. Moreover, HPLC-MS/MS analysis showed that NO(2)-FAs are rapidly metabolized in cultured endothelial cells (ECs) and treatment with NO(2)-FAs stimulated the phosphorylation of eNOS at Ser(1179). These posttranslational modifications of eNOS, in concert with elevated eNOS gene expression, contributed to an increase in endothelial NO production. In aggregate, OA-NO(2)-induced eNOS and HO-1 expression by vascular cells can induce beneficial effects on endothelial function and provide a new strategy for treating various vascular inflammatory and hypertensive disorders.
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Affiliation(s)
- Nicholas K.H. Khoo
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261, USA
- Address correspondence to: Nicholas K.H. Khoo, Ph.D. Department of Pharmacology & Chemical Biology, E1314 BST, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Tel: 412-648-9671; Fax: 412-648-2229; . Bruce A Freeman, Ph.D., Department of Pharmacology & Chemical Biology, E1340 BST, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Tel: 412-648-9319; Fax: 412-648-2229;
| | - Volker Rudolph
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261, USA
- Department of Cardiology, University Heart Center Hamburg, Hamburg, Germany
| | - Marsha P. Cole
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261, USA
| | - Franca Golin-Bisello
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261, USA
| | - Francisco J. Schopfer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261, USA
| | - Steven R. Woodcock
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261, USA
| | | | - Bruce A. Freeman
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, 15261, USA
- Address correspondence to: Nicholas K.H. Khoo, Ph.D. Department of Pharmacology & Chemical Biology, E1314 BST, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Tel: 412-648-9671; Fax: 412-648-2229; . Bruce A Freeman, Ph.D., Department of Pharmacology & Chemical Biology, E1340 BST, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Tel: 412-648-9319; Fax: 412-648-2229;
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42
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Schopfer FJ, Batthyany C, Baker PRS, Bonacci G, Cole MP, Rudolph V, Groeger AL, Rudolph TK, Nadtochiy S, Brookes PS, Freeman BA. Detection and quantification of protein adduction by electrophilic fatty acids: mitochondrial generation of fatty acid nitroalkene derivatives. Free Radic Biol Med 2009; 46:1250-9. [PMID: 19353781 PMCID: PMC3144282 DOI: 10.1016/j.freeradbiomed.2008.12.025] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nitroalkene fatty acid derivatives manifest a strong electrophilic nature, are clinically detectable, and induce multiple transcriptionally regulated anti-inflammatory responses. At present, the characterization and quantification of endogenous electrophilic lipids are compromised by their Michael addition with protein and small-molecule nucleophilic targets. Herein, we report a trans-nitroalkylation reaction of nitro-fatty acids with beta-mercaptoethanol (BME) and apply this reaction to the unbiased identification and quantification of reaction with nucleophilic targets. Trans-nitroalkylation yields are maximal at pH 7 to 8 and occur with physiological concentrations of target nucleophiles. This reaction is also amenable to sensitive mass spectrometry-based quantification of electrophilic fatty acid-protein adducts upon electrophoretic resolution of proteins. In-gel trans-nitroalkylation reactions also permit the identification of protein targets without the bias and lack of sensitivity of current proteomic approaches. Using this approach, it was observed that fatty acid nitroalkenes are rapidly metabolized in vivo by a nitroalkene reductase activity and mitochondrial beta-oxidation, yielding a variety of electrophilic and nonelectrophilic products that could be structurally characterized upon BME-based trans-nitroalkylation reaction. This strategy was applied to the detection and quantification of fatty acid nitration in mitochondria in response to oxidative inflammatory conditions induced by myocardial ischemia-reoxygenation.
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Affiliation(s)
- F J Schopfer
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
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43
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Abstract
The proteasome is a large protease complex consisting of multiple catalytic subunits that function simultaneously to digest protein substrates. This complexity has made deciphering the role each subunit plays in the generation of specific protein fragments difficult. Positional scanning libraries of peptide vinyl sulfones were generated in which the amino acid located directly at the site of hydrolysis (P1 residue) was held constant and sequences distal to that residue (P2, P3, and P4 positions) were varied across all natural amino acids (except cysteine and methionine). Binding information for each of the individual catalytic subunits was obtained for each library under a variety of different conditions. The resulting specificity profiles indicated that substrate positions distal to P1 are critical for directing substrates to active subunits in the complex. Furthermore, specificity profiles of IFN-gamma-regulated subunits closely matched those of their noninducible counterparts, suggesting that subunit swapping may modulate substrate processing by a mechanism that does require a change in the primary sequence specificity of individual catalytic subunits in the complex. Finally, specificity profiles were used to design specific inhibitors of a single active site in the complex. These reagents can be used to further establish the role of each subunit in substrate processing by the proteasome.
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Affiliation(s)
- T Nazif
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA
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