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Dechow SJ, Coulson GB, Wilson MW, Larsen SD, Abramovitch RB. AC2P20 selectively kills Mycobacterium tuberculosis at acidic pH by depleting free thiols. RSC Adv 2021; 11:20089-20100. [PMID: 34168865 PMCID: PMC8176622 DOI: 10.1039/d1ra03181c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) senses and adapts to host immune cues as part of its pathogenesis. One environmental cue sensed by Mtb is the acidic pH of its host niche in the macrophage phagosome. Disrupting the ability of Mtb to sense and adapt to acidic pH has the potential to reduce survival of Mtb in macrophages. Previously, a high throughput screen of a ∼220 000 compound small molecule library was conducted to discover chemical probes that inhibit Mtb growth at acidic pH. The screen discovered chemical probes that kill Mtb at pH 5.7 but are inactive at pH 7.0. In this study, AC2P20 was prioritized for continued study to test the hypothesis that it was targeting Mtb pathways associated with pH-driven adaptation. RNAseq transcriptional profiling studies showed AC2P20 modulates expression of genes associated with redox homeostasis. Gene enrichment analysis revealed that the AC2P20 transcriptional profile had significant overlap with a previously characterized pH-selective inhibitor, AC2P36. Like AC2P36, we show that AC2P20 kills Mtb by selectively depleting free thiols at acidic pH. Mass spectrometry studies show the formation of a disulfide bond between AC2P20 and reduced glutathione, supporting a mechanism where AC2P20 is able to deplete intracellular thiols and dysregulate redox homeostasis. The observation of two independent molecules targeting free thiols to kill Mtb at acidic pH further supports that Mtb has restricted redox homeostasis and sensitivity to thiol-oxidative stress at acidic pH.
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Affiliation(s)
- Shelby J Dechow
- Department of Microbiology and Molecular Genetics, Michigan State University East Lansing MI 48824 USA +1 517 353-8957 +1 517 884-5416
| | - Garry B Coulson
- Department of Microbiology and Molecular Genetics, Michigan State University East Lansing MI 48824 USA +1 517 353-8957 +1 517 884-5416
| | - Michael W Wilson
- Vahlteich Medicinal Chemistry Core, College of Pharmacy, University of Michigan Ann Arbor MI 48109 USA
| | - Scott D Larsen
- Vahlteich Medicinal Chemistry Core, College of Pharmacy, University of Michigan Ann Arbor MI 48109 USA
| | - Robert B Abramovitch
- Department of Microbiology and Molecular Genetics, Michigan State University East Lansing MI 48824 USA +1 517 353-8957 +1 517 884-5416
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Qasim GH, Nguyen VH, Lee S, Lee W, Han S. Countereffect of glutathione on divalent mercury removal by nanoscale zero-valent iron in the presence of natural organic matter. JOURNAL OF HAZARDOUS MATERIALS 2020; 398:122874. [PMID: 32512443 DOI: 10.1016/j.jhazmat.2020.122874] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 04/08/2020] [Accepted: 04/29/2020] [Indexed: 06/11/2023]
Abstract
Although there have been multiple studies on the effects of natural organic matter (NOM) on zero-valent iron (ZVI) removal of several regulated heavy metal ions from contaminated water, the role of NOM on Hg(II) removal by nanoscale ZVI (nZVI) has not yet been studied. The experimental results showed that in the presence of 100 mg L-1 of Suwannee River NOM (SRNOM), the Hg(II) removal ratio by nZVI decreased from 89% to 36% after 80 min of reaction. Similar trends were observed in the long-term test maintained for 15 days, attributable to the surface passivation of nZVI by SRNOM. In contrast, addition of 100 μM glutathione (GSH) to the nZVI suspensions increased the Hg(II) removal ratio from 85% to 96% after 15 days of reaction. Furthermore, adding 100 μM of GSH to the nZVI and SRNOM suspensions largely improved the removal efficiency of Hg(II) to be > 99% after 9 days of reaction, related to the enhanced dissolution of Fe(II) and consequent formation of lepidocrocite and maghemite on the nZVI surface. The addition of thiolic compounds is suggested as a promising step in overcoming the inhibitory effect of SRNOM for the remediation of Hg(II) using nZVI technology.
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Affiliation(s)
- Ghulam Hussain Qasim
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Viet Huu Nguyen
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Sangwook Lee
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea
| | - Woojin Lee
- Department of Civil Engineering, Nazarbayev University, 53 Kabanbay Batyr Ave., Astana 010000, Republic of Kazakhstan.
| | - Seunghee Han
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
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Ajsuvakova OP, Tinkov AA, Aschner M, Rocha JB, Michalke B, Skalnaya MG, Skalny AV, Butnariu M, Dadar M, Sarac I, Aaseth J, Bjørklund G. Sulfhydryl groups as targets of mercury toxicity. Coord Chem Rev 2020; 417:213343. [PMID: 32905350 PMCID: PMC7470069 DOI: 10.1016/j.ccr.2020.213343] [Citation(s) in RCA: 136] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The present study addresses existing data on the affinity and conjugation of sulfhydryl (thiol; -SH) groups of low- and high-molecular-weight biological ligands with mercury (Hg). The consequences of these interactions with special emphasis on pathways of Hg toxicity are highlighted. Cysteine (Cys) is considered the primary target of Hg, and link its sensitivity with thiol groups and cellular damage. In vivo, Hg complexes play a key role in Hg metabolism. Due to the increased affinity of Hg to SH groups in Cys residues, glutathione (GSH) is reactive. The geometry of Hg(II) glutathionates is less understood than that with Cys. Both Cys and GSH Hg-conjugates are important in Hg transport. The binding of Hg to Cys mediates multiple toxic effects of Hg, especially inhibitory effects on enzymes and other proteins that contain free Cys residues. In blood plasma, albumin is the main Hg-binding (Hg2+, CH3Hg+, C2H5Hg+, C6H5Hg+) protein. At the Cys34 residue, Hg2+ binds to albumin, whereas other metals likely are bound at the N-terminal site and multi-metal binding sites. In addition to albumin, Hg binds to multiple Cys-containing enzymes (including manganese-superoxide dismutase (Mn-SOD), arginase I, sorbitol dehydrogenase, and δ-aminolevulinate dehydratase, etc.) involved in multiple processes. The affinity of Hg for thiol groups may also underlie the pathways of Hg toxicity. In particular, Hg-SH may contribute to apoptosis modulation by interfering with Akt/CREB, Keap1/Nrf2, NF-κB, and mitochondrial pathways. Mercury-induced oxidative stress may ensue from Cys-Hg binding and inhibition of Mn-SOD (Cys196), thioredoxin reductase (TrxR) (Cys497) activity, as well as limiting GSH (GS-HgCH3) and Trx (Cys32, 35, 62, 65, 73) availability. Moreover, Hg-thiol interaction also is crucial in the neurotoxicity of Hg by modulating the cytoskeleton and neuronal receptors, to name a few. However, existing data on the role of Hg-SH binding in the Hg toxicity remains poorly defined. Therefore, more research is needed to understand better the role of Hg-thiol binding in the molecular pathways of Hg toxicology and the critical role of thiols to counteract negative effects of Hg overload.
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Affiliation(s)
- Olga P. Ajsuvakova
- Yaroslavl State University, Yaroslavl, Russia
- Federal Scientific Center of Biological Systems and Agrotechnologies of the Russian Academy of Sciences, Orenburg, Russia
- IM Sechenov First Moscow State Medical University, Moscow, Russia
| | - Alexey A. Tinkov
- Yaroslavl State University, Yaroslavl, Russia
- Federal Scientific Center of Biological Systems and Agrotechnologies of the Russian Academy of Sciences, Orenburg, Russia
- IM Sechenov First Moscow State Medical University, Moscow, Russia
| | - Michael Aschner
- IM Sechenov First Moscow State Medical University, Moscow, Russia
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - João B.T. Rocha
- Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | | | | | - Anatoly V. Skalny
- Yaroslavl State University, Yaroslavl, Russia
- Federal Scientific Center of Biological Systems and Agrotechnologies of the Russian Academy of Sciences, Orenburg, Russia
- IM Sechenov First Moscow State Medical University, Moscow, Russia
| | - Monica Butnariu
- Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
- CONEM Romania Biotechnology and Environmental Sciences Group, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Ioan Sarac
- Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
- CONEM Romania Biotechnology and Environmental Sciences Group, Banat’s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania” from Timișoara, Timişoara, Romania
| | - Jan Aaseth
- IM Sechenov First Moscow State Medical University, Moscow, Russia
- Research Department, Innlandet Hospital Trust, Brumunddal, Norway
| | - Geir Bjørklund
- Council for Nutritional and Environmental Medicine (CONEM), Mo i Rana, Norway
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