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American Journal of Physiology. Cell... Jun 2003Nuclear, mitochondrial, and plasma membrane events associated with apoptosis were investigated in rat neutrophils cultivated for 3, 24, and 48 h in the absence or...
Nuclear, mitochondrial, and plasma membrane events associated with apoptosis were investigated in rat neutrophils cultivated for 3, 24, and 48 h in the absence or presence of glutamine (0.5, 1.0, and 2.0 mM). Condensation of chromatin was reduced after 24 or 48 h of culture in the presence of glutamine compared with its absence as assessed by Hoechst 33342 staining. The level of Escherichia coli phagocytosis in the presence of glutamine was markedly increased compared with the level achieved by cells cultured in the absence of glutamine. Annexin V binding to externalized phosphatidylserine was reduced in the presence of glutamine. Sensitive fluorochrome rhodamine 123, as determined by fluorescence-activated cell sorting and confocal microscopy, was used to monitor loss of the mitochondrial transmembrane potential. In the absence of glutamine, neutrophils exhibited a marked reduction in the uptake of rhodamine 123. In the presence of 1.0 or 2.0 mM glutamine, the uptake of rhodamine was 20 or 38% higher, respectively. Similar effect was found in human neutrophils by measuring DNA fragmentation and mitochondrial transmembrane potential. Therefore, glutamine protects from events associated with triggering and executing apoptosis in both rat and human neutrophils.
Topics: Animals; Apoptosis; Cells, Cultured; Chromatin; Diazooxonorleucine; Dose-Response Relationship, Drug; Enzyme Inhibitors; Glutamine; Humans; Male; Membrane Potentials; Mitochondria; Neutrophils; Phagocytosis; Phosphatidylserines; Rats; Rats, Wistar
PubMed: 12529242
DOI: 10.1152/ajpcell.00224.2002 -
ELife Jun 2018Energy metabolism is essential for T cell function. However, how persistent antigenic stimulation affects T cell metabolism is unknown. Here, we report that long-term in...
Energy metabolism is essential for T cell function. However, how persistent antigenic stimulation affects T cell metabolism is unknown. Here, we report that long-term in vivo antigenic exposure induced a specific deficit in numerous metabolic enzymes. Accordingly, T cells exhibited low basal glycolytic flux and limited respiratory capacity. Strikingly, blockade of inhibitory receptor PD-1 stimulated the production of IFNγ in chronic T cells, but failed to shift their metabolism towards aerobic glycolysis, as observed in effector T cells. Instead, chronic T cells appeared to rely on oxidative phosphorylation (OXPHOS) and fatty acid oxidation (FAO) to produce ATP for IFNγ synthesis. Check-point blockade, however, increased mitochondrial production of superoxide and reduced viability and effector function. Thus, in the absence of a glycolytic switch, PD-1-mediated inhibition appears essential for limiting oxidative metabolism linked to effector function in chronic T cells, thereby promoting survival and functional fitness.
Topics: Adenosine Triphosphate; Animals; Antibodies, Monoclonal; Antimetabolites, Antineoplastic; B7-H1 Antigen; Cell Lineage; DNA-Binding Proteins; Diazooxonorleucine; Epoxy Compounds; Gene Expression Profiling; Gene Expression Regulation; Glycolysis; Interferon-gamma; Interleukin Receptor Common gamma Subunit; Lymphocyte Activation; Male; Mice; Mice, Inbred BALB C; Mice, Knockout; Oligomycins; Oxidative Phosphorylation; Programmed Cell Death 1 Receptor; Receptors, Antigen, T-Cell; Signal Transduction; T-Lymphocytes; Transplantation, Homologous
PubMed: 29911570
DOI: 10.7554/eLife.30938 -
Nature Oct 2013Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is an enzyme with important regulatory functions in the heart and brain, and its chronic activation can be...
Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is an enzyme with important regulatory functions in the heart and brain, and its chronic activation can be pathological. CaMKII activation is seen in heart failure, and can directly induce pathological changes in ion channels, Ca(2+) handling and gene transcription. Here, in human, rat and mouse, we identify a novel mechanism linking CaMKII and hyperglycaemic signalling in diabetes mellitus, which is a key risk factor for heart and neurodegenerative diseases. Acute hyperglycaemia causes covalent modification of CaMKII by O-linked N-acetylglucosamine (O-GlcNAc). O-GlcNAc modification of CaMKII at Ser 279 activates CaMKII autonomously, creating molecular memory even after Ca(2+) concentration declines. O-GlcNAc-modified CaMKII is increased in the heart and brain of diabetic humans and rats. In cardiomyocytes, increased glucose concentration significantly enhances CaMKII-dependent activation of spontaneous sarcoplasmic reticulum Ca(2+) release events that can contribute to cardiac mechanical dysfunction and arrhythmias. These effects were prevented by pharmacological inhibition of O-GlcNAc signalling or genetic ablation of CaMKIIδ. In intact perfused hearts, arrhythmias were aggravated by increased glucose concentration through O-GlcNAc- and CaMKII-dependent pathways. In diabetic animals, acute blockade of O-GlcNAc inhibited arrhythmogenesis. Thus, O-GlcNAc modification of CaMKII is a novel signalling event in pathways that may contribute critically to cardiac and neuronal pathophysiology in diabetes and other diseases.
Topics: Acetylglucosamine; Animals; Arrhythmias, Cardiac; Benzylamines; Brain; Calcium; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Diabetes Complications; Diazooxonorleucine; Enzyme Activation; Glucose; Glycosylation; Humans; Hyperglycemia; Mice; Myocardium; Myocytes, Cardiac; Rats; Sarcoplasmic Reticulum; Sulfonamides
PubMed: 24077098
DOI: 10.1038/nature12537 -
Brazilian Oral Research 2023The current study aims to assess the effectiveness of e-learning in compliance with the new biosafety recommendations in dentistry in the context of COVID-19 applied to...
The current study aims to assess the effectiveness of e-learning in compliance with the new biosafety recommendations in dentistry in the context of COVID-19 applied to the clinical staff of a dental school in Brazil. A quasi-experimental epidemiological study was carried out by means of a structured, pre-tested online questionnaire, applied before and after an educational intervention, using an e-learning format. After data collection, statistical tests were performed. A total of 549 members of the clinical staff participated in the study in the two collection phases, with a return rate of 26.9%. After the e-learning stage, a reduction was found in the reported use of disposable gloves, protective goggles, and surgical masks. The course had no impact on the staff's knowledge concerning the proper sequence for donning PPE and showed 100% effectiveness regarding proper PPE doffing sequence. Knowledge about avoiding procedures that generate aerosols in the clinical setting was improved. Despite the low rate of return, it can be concluded that online intervention alone was ineffective in significantly improving learning about the new clinical biosafety guidelines. Therefore, the use of hybrid teaching and repetitive training is highly recommended.
Topics: Humans; Computer-Assisted Instruction; COVID-19; Brazil; Diazooxonorleucine; Dentistry
PubMed: 37341233
DOI: 10.1590/1807-3107bor-2023.vol37.0060 -
Communications Biology 2019Glioblastoma (GBM) is an aggressive primary human brain tumour that has resisted effective therapy for decades. Although glucose and glutamine are the major fuels that...
Glioblastoma (GBM) is an aggressive primary human brain tumour that has resisted effective therapy for decades. Although glucose and glutamine are the major fuels that drive GBM growth and invasion, few studies have targeted these fuels for therapeutic management. The glutamine antagonist, 6-diazo-5-oxo-L-norleucine (DON), was administered together with a calorically restricted ketogenic diet (KD-R) to treat late-stage orthotopic growth in two syngeneic GBM mouse models: VM-M3 and CT-2A. DON targets glutaminolysis, while the KD-R reduces glucose and, simultaneously, elevates neuroprotective and non-fermentable ketone bodies. The diet/drug therapeutic strategy killed tumour cells while reversing disease symptoms, and improving overall mouse survival. The therapeutic strategy also reduces edema, hemorrhage, and inflammation. Moreover, the KD-R diet facilitated DON delivery to the brain and allowed a lower dosage to achieve therapeutic effect. The findings support the importance of glucose and glutamine in driving GBM growth and provide a therapeutic strategy for non-toxic metabolic management.
Topics: Animals; Body Weight; Brain; Brain Neoplasms; Caloric Restriction; Cell Line, Tumor; Cell Proliferation; Diazooxonorleucine; Diet, Ketogenic; Disease Models, Animal; Female; Fermentation; Glioblastoma; Glucose; Glutamine; Humans; Immunohistochemistry; Ketone Bodies; Ketones; Male; Mice; Mice, Inbred C57BL; Neoplasm Transplantation
PubMed: 31149644
DOI: 10.1038/s42003-019-0455-x -
Proceedings of the National Academy of... Dec 2018The deadliest complication of infection is cerebral malaria (CM), with a case fatality rate of 15 to 25% in African children despite effective antimalarial...
The deadliest complication of infection is cerebral malaria (CM), with a case fatality rate of 15 to 25% in African children despite effective antimalarial chemotherapy. No adjunctive treatments are yet available for this devastating disease. We previously reported that the glutamine antagonist 6-diazo-5-oxo-l-norleucine (DON) rescued mice from experimental CM (ECM) when administered late in the infection, a time by which mice had already suffered blood-brain barrier (BBB) dysfunction, brain swelling, and hemorrhaging. Herein, we used longitudinal MR imaging to visualize brain pathology in ECM and the impact of a new DON prodrug, JHU-083, on disease progression in mice. We demonstrate in vivo the reversal of disease markers in symptomatic, infected mice following treatment, including the resolution of edema and BBB disruption, findings usually associated with a fatal outcome in children and adults with CM. Our results support the premise that JHU-083 is a potential adjunctive treatment that could rescue children and adults from fatal CM.
Topics: Adult; Animals; Antimalarials; Biomarkers; Blood-Brain Barrier; Brain; Brain Edema; Child; Diazooxonorleucine; Disease Models, Animal; Disease Progression; Female; Glutamine; Humans; Magnetic Resonance Imaging; Malaria, Cerebral; Malaria, Falciparum; Mice; Mice, Inbred C57BL; Plasmodium falciparum
PubMed: 30514812
DOI: 10.1073/pnas.1812909115 -
Journal of Medicinal Chemistry Apr 20196-Diazo-5-oxo-l-norleucine (DON) is a glutamine antagonist with robust anticancer efficacy; however, its therapeutic potential was hampered by its biodistribution and...
6-Diazo-5-oxo-l-norleucine (DON) is a glutamine antagonist with robust anticancer efficacy; however, its therapeutic potential was hampered by its biodistribution and toxicity to normal tissues, specifically gastrointestinal (GI) tissues. To circumvent DON's toxicity, we synthesized a series of tumor-targeted DON prodrugs designed to circulate inert in plasma and preferentially activate over DON in tumor. Our best prodrug 6 (isopropyl 2-(6-acetamido-2-(adamantane-1-carboxamido)hexanamido)-6-diazo-5-oxohexanoate) showed stability in plasma, liver, and intestinal homogenates yet was readily cleaved to DON in P493B lymphoma cells, exhibiting a 55-fold enhanced tumor cell-to-plasma ratio versus that of DON and resulting in a dose-dependent inhibition of cell proliferation. Using carboxylesterase 1 knockout mice that were shown to mimic human prodrug metabolism, systemic administration of 6 delivered 11-fold higher DON exposure to tumor (target tissue; AUC = 5.1 nmol h/g) versus GI tissues (toxicity tissue; AUC = 0.45 nmol h/g). In summary, these studies describe the discovery of a glutamine antagonist prodrug that provides selective tumor exposure.
Topics: Acetylation; Animals; Antineoplastic Agents; Area Under Curve; Carboxylic Ester Hydrolases; Cell Line, Tumor; Diazooxonorleucine; Drug Delivery Systems; Humans; Lysine; Mice; Mice, Knockout; Prodrugs; Swine
PubMed: 30892035
DOI: 10.1021/acs.jmedchem.8b02009 -
Scientific Reports Aug 2017Pancreatic cancer is a lethal disease with poor prognosis. Gemcitabine has been the first line systemic treatment for pancreatic cancer. However, the rapid development...
Pancreatic cancer is a lethal disease with poor prognosis. Gemcitabine has been the first line systemic treatment for pancreatic cancer. However, the rapid development of drug resistance has been a major hurdle in gemcitabine therapy leading to unsatisfactory patient outcomes. With the recent renewed understanding of glutamine metabolism involvement in drug resistance and immuno-response, we investigated the anti-tumor effect of a glutamine analog (6-diazo-5-oxo-L-norleucine) as an adjuvant treatment to sensitize chemoresistant pancreatic cancer cells. We demonstrate that disruption of glutamine metabolic pathways improves the efficacy of gemcitabine treatment. Such a disruption induces a cascade of events which impacts glycan biosynthesis through Hexosamine Biosynthesis Pathway (HBP), as well as cellular redox homeostasis, resulting in global changes in protein glycosylation, expression and functional effects. The proteome alterations induced in the resistant cancer cells and the secreted exosomes are intricately associated with the reduction in cell proliferation and the enhancement of cancer cell chemosensitivity. Proteins associated with EGFR signaling, including downstream AKT-mTOR pathways, MAPK pathway, as well as redox enzymes were downregulated in response to disruption of glutamine metabolic pathways.
Topics: Cell Line, Tumor; Cell Proliferation; Cell Survival; Deoxycytidine; Diazooxonorleucine; Drug Resistance, Neoplasm; Drug Synergism; Glutamine; Humans; Metabolic Networks and Pathways; Oxidation-Reduction; Pancreatic Neoplasms; Proteomics; Gemcitabine
PubMed: 28801576
DOI: 10.1038/s41598-017-08436-6 -
Protein Science : a Publication of the... Jun 2017Intense efforts are underway to identify inhibitors of the enzyme gamma-glutamyl transpeptidase 1 (GGT1) which cleaves extracellular gamma-glutamyl compounds and...
Intense efforts are underway to identify inhibitors of the enzyme gamma-glutamyl transpeptidase 1 (GGT1) which cleaves extracellular gamma-glutamyl compounds and contributes to the pathology of asthma, reperfusion injury and cancer. The glutamate analog, 6-diazo-5-oxo-norleucine (DON), inhibits GGT1. DON also inhibits many essential glutamine metabolizing enzymes rendering it too toxic for use in the clinic as a GGT1 inhibitor. We investigated the molecular mechanism of human GGT1 (hGGT1) inhibition by DON to determine possible strategies for increasing its specificity for hGGT1. DON is an irreversible inhibitor of hGGT1. The second order rate constant of inactivation was 0.052 mM min and the K was 2.7 ± 0.7 mM. The crystal structure of DON-inactivated hGGT1 contained a molecule of DON without the diazo-nitrogen atoms in the active site. The overall structure of the hGGT1-DON complex resembled the structure of the apo-enzyme; however, shifts were detected in the loop forming the oxyanion hole and elements of the main chain that form the entrance to the active site. The structure of hGGT1-DON complex revealed two covalent bonds between the enzyme and inhibitor which were part of a six membered ring. The ring included the OG atom of Thr381, the reactive nucleophile of hGGT1 and the α-amine of Thr381. The structure of DON-bound hGGT1 has led to the discovery of a new mechanism of inactivation by DON that differs from its inactivation of other glutamine metabolizing enzymes, and insight into the activation of the catalytic nucleophile that initiates the hGGT1 reaction.
Topics: Catalytic Domain; Crystallography, X-Ray; Diazooxonorleucine; Enzyme Inhibitors; Humans; Protein Structure, Secondary; gamma-Glutamyltransferase
PubMed: 28378915
DOI: 10.1002/pro.3172 -
Drug Discoveries & Therapeutics Nov 2023This work describes a novel artificial intelligence-based training and monitoring system (AITMS) that was used to control and prevent nosocomial infections (NIs) by...
This work describes a novel artificial intelligence-based training and monitoring system (AITMS) that was used to control and prevent nosocomial infections (NIs) by improving the skills of donning/removing personal protective equipment (PPE). The AITMS has two working modes, namely an AI-based protective equipment surveillance mode and an AI-based training mode, that were used for routine surveillance and training, respectively. Data revealed that the accuracy rate of donning/removing PPE improved as a result of the AITMS. Interestingly, the frequency of NIs decreased with the use of the AITMS. This study suggested the key role of using PPE in controlling and preventing NIs. Data preliminarily proved that appropriate donning/removing PPE may help to reduce the risk of NIs. In addition, the newest computerized technologies, such as AI, have proven to be useful in controlling and preventing NIs. These findings should helpful to formulate a better strategy against NIs in the future.
Topics: Humans; Artificial Intelligence; Pilot Projects; Cross Infection; Diazooxonorleucine; Hospitals
PubMed: 37673650
DOI: 10.5582/ddt.2023.01068