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Nature Immunology May 2020Oxidative stress is a central part of innate immune-induced neurodegeneration. However, the transcriptomic landscape of central nervous system (CNS) innate immune cells...
Oxidative stress is a central part of innate immune-induced neurodegeneration. However, the transcriptomic landscape of central nervous system (CNS) innate immune cells contributing to oxidative stress is unknown, and therapies to target their neurotoxic functions are not widely available. Here, we provide the oxidative stress innate immune cell atlas in neuroinflammatory disease and report the discovery of new druggable pathways. Transcriptional profiling of oxidative stress-producing CNS innate immune cells identified a core oxidative stress gene signature coupled to coagulation and glutathione-pathway genes shared between a microglia cluster and infiltrating macrophages. Tox-seq followed by a microglia high-throughput screen and oxidative stress gene network analysis identified the glutathione-regulating compound acivicin, with potent therapeutic effects that decrease oxidative stress and axonal damage in chronic and relapsing multiple sclerosis models. Thus, oxidative stress transcriptomics identified neurotoxic CNS innate immune populations and may enable discovery of selective neuroprotective strategies.
Topics: Animals; Antioxidants; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Female; Gene Expression Profiling; Gene Regulatory Networks; High-Throughput Screening Assays; Humans; Immunity, Innate; Isoxazoles; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Microglia; Multiple Sclerosis; Neurogenic Inflammation; Oxidative Stress; Sequence Analysis, RNA; Single-Cell Analysis
PubMed: 32284594
DOI: 10.1038/s41590-020-0654-0 -
PLoS Neglected Tropical Diseases Dec 2021Studies of drug resistance in the protozoan parasites of the genus Leishmania have been helpful in revealing biochemical pathways as potential drug targets. The...
Studies of drug resistance in the protozoan parasites of the genus Leishmania have been helpful in revealing biochemical pathways as potential drug targets. The chlorinated glutamine analogue acivicin has shown good activity against Leishmania cells and was shown to target several enzymes containing amidotransferase domains. We selected a Leishmania tarentolae clone for acivicin resistance. The genome of this resistant strain was sequenced and the gene coding for the amidotransferase domain-containing GMP synthase was found to be amplified. Episomal expression of this gene in wild-type L. tarentolae revealed a modest role in acivicin resistance. The most prominent defect observed in the resistant mutant was reduced uptake of glutamate, and through competition experiments we determined that glutamate and acivicin, but not glutamine, share the same transporter. Several amino acid transporters (AATs) were either deleted or mutated in the resistant cells. Some contributed to the acivicin resistance phenotype although none corresponded to the main glutamate transporter. Through sequence analysis one AAT on chromosome 22 corresponded to the main glutamate transporter. Episomal expression of the gene coding for this transporter in the resistant mutant restored glutamate transport and acivicin susceptibility. Its genetic knockout led to reduced glutamate transport and acivicin resistance. We propose that acivicin binds covalently to this transporter and as such leads to decreased transport of glutamate and acivicin thus leading to acivicin resistance.
Topics: Amino Acid Transport Systems; Antiprotozoal Agents; Biological Transport; Drug Resistance; Glutamic Acid; Humans; Isoxazoles; Leishmania; Leishmaniasis; Protozoan Proteins
PubMed: 34914690
DOI: 10.1371/journal.pntd.0010046 -
Annals of Surgery Dec 1993This overview on glutamine and cancer discusses the importance of glutamine for tumor growth, summarizes the alterations in interorgan glutamine metabolism that develop... (Review)
Review
OBJECTIVE
This overview on glutamine and cancer discusses the importance of glutamine for tumor growth, summarizes the alterations in interorgan glutamine metabolism that develop in the tumor-bearing host, and reviews the potential benefits of glutamine nutrition in the patient with cancer.
SUMMARY BACKGROUND DATA
Glutamine is the most abundant amino acid in the blood and tissues. It is essential for tumor growth and marked changes in organ glutamine metabolism are characteristic of the host with cancer. Because host glutamine depletion has adverse effects, it is important to study the regulation of glutamine metabolism in cancer and to evaluate the impact of glutamine nutrition in the tumor-bearing state.
METHODS
Data from a variety of investigations on glutamine metabolism and nutrition related to the host with cancer were compiled and summarized.
RESULTS
Numerous studies on glutamine metabolism in cancer indicate that many tumors are avid glutamine consumers in vivo and in vitro. As a consequence of progressive tumor growth, host glutamine depletion develops and becomes a hallmark. This glutamine depletion occurs in part because the tumor behaves as a "glutamine trap" but also because of cytokine-mediated alterations in glutamine metabolism in host tissues. Animal and human studies that have investigated the use of glutamine-supplemented nutrition in the host with cancer suggest that pharmacologic doses of dietary glutamine may be beneficial.
CONCLUSIONS
Understanding the control of glutamine metabolism in the tumor-bearing host not only improves the knowledge of metabolic regulation in the patient with cancer but also will lead to improved nutritional support regimens targeted to benefit the host.
Topics: Antimetabolites, Antineoplastic; Cell Division; Diazooxonorleucine; Glutamine; Humans; Intestinal Mucosa; Intestines; Isoxazoles; Lymphocytes; Muscles; Neoplasms; Parenteral Nutrition, Total; Randomized Controlled Trials as Topic
PubMed: 8257221
DOI: 10.1097/00000658-199312000-00004 -
Blood Jun 1992We have previously noted that the glutamine antagonist acivicin (alpha S,5S-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid) induces monocytoid differentiation...
Inhibition of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) messenger RNA (mRNA) expression in HL-60 leukemia cells by pentoxifylline and dexamethasone: dissociation of acivicin-induced TNF-alpha and IL-1 beta mRNA expression from acivicin-induced monocytoid...
We have previously noted that the glutamine antagonist acivicin (alpha S,5S-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid) induces monocytoid differentiation of freshly isolated human myeloid leukemia cells and cells of the myeloid leukemia cell line HL-60, and that the differentiation is accompanied by increases in expression of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta). Because we also showed that TNF-alpha and IL-1 beta can act synergistically to cause monocytoid differentiation of HL-60 cells, we hypothesized that acivicin-induced TNF-alpha and IL-1 beta, in an autocrine manner, caused the differentiation. The purpose of the present study was to determine the causal roles of TNF-alpha and IL-1 beta in the acivicin-induced differentiation of HL-60 cells by the use of dexamethasone (DEX) and pentoxifylline (PTX), two drugs that effectively inhibit expression of TNF-alpha and IL-1 beta. Acivicin caused a monocytoid differentiation of the cells as manifest by diminished cell growth, morphologic maturation of the cells, increased ability to generate hydrogen peroxide in response to acute treatment with phorbol myristate acetate, and increased expression of nonspecific esterase and the surface antigens CD14 and CD11b. Acivicin treatment also caused the cells to have diminished steady-state expression of messenger RNA (mRNA) for c-myc and c-myb, and increased expression of mRNA for TNF-alpha and IL-1 beta. DEX and PTX did not alter cell growth, and did not block the acivicin-induced block in growth. PTX caused a slight increase in nonspecific esterase expression, but DEX had no effect on this, and neither drug diminished the acivicin-induced increase in nonspecific esterase. Although neither drug alone lessened the acivicin enhancement of hydrogen peroxide production, DEX and PTX together reduced this. DEX did not modify the acivicin-induced morphologic maturation of the cells, but PTX alone or PTX with DEX potentiated the acivicin-induced increase in mature cells. Basal CD14 and CD11b expression were slightly reduced by DEX and PTX, but neither drug modified the acivicin-induced increases. DEX and PTX reduced the acivicin-induced increases in TNF-alpha and IL-1 beta mRNA expression, but they had little or no effect on the acivicin-induced decreases in expression of mRNA for c-myc and c-myb. Thus, DEX and PTX effectively block the acivicin-induced expression of TNF-alpha and IL-1 beta, but they have little influence on the acivicin-induced differentiation process.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Cell Differentiation; Dexamethasone; Esterases; Gene Expression; Genes, myc; Humans; Hydrogen Peroxide; Interleukin-1; Isoxazoles; Leukemia, Promyelocytic, Acute; Pentoxifylline; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-myb; RNA, Messenger; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha
PubMed: 1596574
DOI: No ID Found -
Molecules (Basel, Switzerland) Apr 2023Chiral natural compounds are often biosynthesized in an enantiomerically pure fashion, and stereochemistry plays a pivotal role in biological activity. Herein, we...
Chiral natural compounds are often biosynthesized in an enantiomerically pure fashion, and stereochemistry plays a pivotal role in biological activity. Herein, we investigated the significance of chirality for nature-inspired 3-Br-acivicin (3-BA) and its derivatives. The three unnatural isomers of 3-BA and its ester and amide derivatives were prepared and characterized for their antimalarial activity. Only the (5, α) isomers displayed significant antiplasmodial activity, revealing that their uptake might be mediated by the L-amino acid transport system, which is known to mediate the acivicin membrane's permeability. In addition, we investigated the inhibitory activity towards glyceraldehyde 3-phosphate dehydrogenase (GAPDH) since it is involved in the multitarget mechanism of action of 3-BA. Molecular modeling has shed light on the structural and stereochemical requirements for an efficient interaction with GAPDH, leading to covalent irreversible binding and enzyme inactivation. While stereochemistry affects the target binding only for two subclasses (- and -), it leads to significant differences in the antimalarial activity for all subclasses, suggesting that a stereoselective uptake might be responsible for the enhanced biological activity of the (5, α) isomers.
Topics: Antimalarials; Isoxazoles; Plasmodium falciparum; Models, Molecular
PubMed: 37049935
DOI: 10.3390/molecules28073172 -
The Journal of Biological Chemistry Nov 1986Acivicin (NSC 163501) and dichloroallyl lawsone (NSC 126771) are potent inhibitors of nucleotide biosynthesis with consequent anti-cancer activity against certain...
Acivicin (NSC 163501) and dichloroallyl lawsone (NSC 126771) are potent inhibitors of nucleotide biosynthesis with consequent anti-cancer activity against certain experimental tumors. To determine in detail the metabolic events induced by each inhibitor, we have devised a new two-dimensional chromatographic procedure for measurement of the concentrations of all pyrimidine intermediates and some purine nucleotides from 100 microliter of an extract of cells grown in the presence of [14C]bicarbonate. Addition of acivicin (25 microM) to mouse L1210 leukemia cells causes severe depletion in the cellular levels of CTP and GTP, accumulation of uridine nucleotides, and abrupt but transient increases in the concentrations of the early intermediates of both the pyrimidine and purine pathways. Addition of dichloroallyl lawsone (25 microM) results in a rapid depletion of uridine and cytidine nucleotides; carbamyl aspartate and dihydroorotate accumulate to high levels in an equilibrium ratio of 20.5:1, and orotate, orotidine, and UMP increase transiently before decreasing to levels approaching their original steady states. The predominant inhibitory effects of acivicin are upon the reactions UTP----CTP and XMP----GMP, but there is also an initial transient activation of both the pyrimidine and purine pathways by acivicin. The data obtained with dichloroallyl lawsone are consistent with inhibition of the conversion of UMP----UDP initially followed by potent inhibition of dihydroorotate----orotate.
Topics: Animals; Bicarbonates; Carbon Radioisotopes; Cytidine Triphosphate; Guanosine Triphosphate; Isoxazoles; Kinetics; Leukemia L1210; Mice; Naphthoquinones; Oxazoles; Pyrimidines; Uracil Nucleotides
PubMed: 3771555
DOI: No ID Found -
Proceedings of the National Academy of... Mar 1995Acivicin is a potent inhibitor of gamma-glutamyl transpeptidase (EC 2.3.2.2), an enzyme of importance in glutathione metabolism. Acivicin inhibition and binding are... (Comparative Study)
Comparative Study
Acivicin is a potent inhibitor of gamma-glutamyl transpeptidase (EC 2.3.2.2), an enzyme of importance in glutathione metabolism. Acivicin inhibition and binding are prevented by gamma-glutamyl substrates and analogs (e.g., serine plus borate), consistent with the previous postulate that acivicin and substrates bind to the same enzyme site. Inactivation of rat kidney transpeptidase by acivicin leads to its binding as an ester to Thr-523. The pig enzyme, which has Ala-523 in place of Thr-523, is inhibited by acivicin with esterification at Ser-405. The human enzyme has Thr-524 (corresponding to Thr-523 in rat); its inactivation leads to esterification of Ser-406 (corresponding to Ser-405 in rat and pig). Hydroxylamine treatment of the acivicin-inactivated enzymes restores activity and releases the acivicin-derived threo-beta-hydroxyglutamate moiety. The findings indicate that there are significant structural differences between the active site region of the rat enzyme and the active site regions of the human and pig. Human mutant enzymes in which Thr-524 and Ser-406 were replaced by Ala, separately and together, are enzymatically active, indicating that these amino acid residues are not required for catalysis. However, esterification of these residues (and of another near the active site) effectively blocks the active site or hinders its function. Acivicin can bind at enzyme sites that are close to that at which gamma-glutamylation occurs; it may bind at the latter site and then be transesterified to another enzyme site.
Topics: Alanine; Amino Acid Sequence; Animals; Antimetabolites; Base Sequence; Binding Sites; Cloning, Molecular; DNA Primers; Humans; Hydroxylamine; Hydroxylamines; Isoxazoles; Kidney; Kinetics; Molecular Sequence Data; Mutagenesis, Site-Directed; Peptide Fragments; Point Mutation; Rats; Recombinant Proteins; Restriction Mapping; Serine; Swine; Threonine; gamma-Glutamyltransferase
PubMed: 7892271
DOI: 10.1073/pnas.92.6.2360 -
Proceedings of the National Academy of... Feb 2019Glutamate is the most abundant excitatory neurotransmitter, present at the bulk of cortical synapses, and participating in many physiologic and pathologic processes...
Glutamate is the most abundant excitatory neurotransmitter, present at the bulk of cortical synapses, and participating in many physiologic and pathologic processes ranging from learning and memory to stroke. The tripeptide, glutathione, is one-third glutamate and present at up to low millimolar intracellular concentrations in brain, mediating antioxidant defenses and drug detoxification. Because of the substantial amounts of brain glutathione and its rapid turnover under homeostatic control, we hypothesized that glutathione is a relevant reservoir of glutamate and could influence synaptic excitability. We find that drugs that inhibit generation of glutamate by the glutathione cycle elicit decreases in cytosolic glutamate and decreased miniature excitatory postsynaptic potential (mEPSC) frequency. In contrast, pharmacologically decreasing the biosynthesis of glutathione leads to increases in cytosolic glutamate and enhanced mEPSC frequency. The glutathione cycle can compensate for decreased excitatory neurotransmission when the glutamate-glutamine shuttle is inhibited. Glutathione may be a physiologic reservoir of glutamate neurotransmitter.
Topics: Animals; Cells, Cultured; Excitatory Postsynaptic Potentials; Glutamic Acid; Glutathione; Homeostasis; Neurons; Rats, Sprague-Dawley; Synapses; Synaptic Transmission
PubMed: 30692251
DOI: 10.1073/pnas.1817885116 -
Annals of Surgery Oct 1988The effect that a 14-day treatment program of total parenteral nutrition (TPN) combined with the glutamine antimetabolite, acivicin, and anabolic hormone, insulin, has...
The effect that a 14-day treatment program of total parenteral nutrition (TPN) combined with the glutamine antimetabolite, acivicin, and anabolic hormone, insulin, has on carcass weight and muscle sparing was investigated in tumor-bearing rats. Although TPN resulted in increased carcass weight gain as compared to chow-fed tumor-bearing rats, no savings in gastrocnemius muscle could be demonstrated. The combination of TPN with daily insulin treatment elicited significant increases in both carcass weight and muscle savings, with no alteration in tumor growth. Although combining acivicin with TPN halted tumor growth and increased carcass weight, the change in carcass weight was less than that observed with the insulin-TPN combination. No muscle savings were observed in the acivicin-TPN-treated rats. Yet when acivicin and insulin were combined with TPN, tumor growth was stopped, carcass weight was gained, and muscle mass was saved. Therefore, these experiments suggest that it is possible to add lean body tissue and stabilize tumor growth in rats that receive TPN through anabolic hormone treatment combined with an inhibitor of tumor metabolism.
Topics: Animals; Antimetabolites; Body Weight; Eating; Energy Intake; Insulin; Isoxazoles; Male; Muscle Proteins; Muscles; Organ Size; Oxazoles; Parenteral Nutrition, Total; Rats; Rats, Inbred F344; Sarcoma, Experimental
PubMed: 3140745
DOI: 10.1097/00000658-198810000-00014 -
Translational Vision Science &... Jul 2020To investigate whether human donor lenses are capable of exporting reduced glutathione.
PURPOSE
To investigate whether human donor lenses are capable of exporting reduced glutathione.
METHODS
Human lenses of varying ages were cultured in artificial aqueous humor for 1 hour under hypoxic conditions to mimic the physiologic environment and reduced glutathione (GSH) and oxidized glutathione (GSSG) levels measured in the media and in the lens.
RESULTS
Human donor lenses released both GSH and GSSG into the media. Donor lenses cultured in the presence of acivicin, a γ-glutamyltranspeptidase inhibitor, exhibited a significant increase in GSSG levels ( < 0.05), indicating that GSSG undergoes degradation into its constituent amino acids. Screening of GSH/GSSG efflux transporters revealed Mrp1, Mrp4, and Mrp5 to be present at the transcript level, but only Mrp5 was expressed at the protein level. Blocking Mrp5 function with the Mrp inhibitor MK571 led to a significant decrease in GSSG efflux ( < 0.05), indicating that Mrp5 is likely to be involved in mediating GSSG efflux. Measurements of efflux from the anterior and posterior surface of the lens revealed that GSH and GSSG efflux occurs at both surfaces but predominantly at the anterior surface.
CONCLUSIONS
Human lenses export GSH and GSSG into the surrounding ocular humors, which can be recycled by the lens to maintain intracellular GSH homeostasis or used by neighboring tissues to maintain GSH levels.
TRANSLATIONAL RELEVANCE
Early removal of a clear lens, as occurs to treat myopia and presbyopia, would eliminate this GSH reservoir and reduce the supply of GSH to other tissues, which, over time, may have clinical implications for the progression of other ocular diseases associated with oxidative stress.
Topics: Biological Transport; Glutathione; Glutathione Disulfide; Humans; Lens, Crystalline; Oxidative Stress
PubMed: 32855883
DOI: 10.1167/tvst.9.8.37