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1.
Reprod Biol Endocrinol ; 18(1): 58, 2020 Jun 03.
Article in English | MEDLINE | ID: mdl-32493421

ABSTRACT

BACKGROUND: Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disease with unknown pathogenesis. However, the treatment of Diane-35 combined with metformin can improve the endocrine and ovulation of PCOS. In this study, we investigated the effects of Diane-35 combined with metformin (DM) treatment on ovulation and glucose metabolism in a PCOS rat model. METHODS: Sprague Dawley rats were divided into 3 groups, control group, model group (PCOS group) and Diane-35 combined with metformin (PCOS + DM group). The mRNA expression levels were determined by qRT-PCR. The hormone levels were determined by enzyme-linked immunosorbent assay. Immunostaining detected the protein levels of lactate dehydrogenase A (LDH-A), pyruvate kinase isozyme M2 (PKM2) and sirtuin 1 (SIRT1) in the ovarian tissues. TNUEL assay was performed to determine cell apoptosis in the PCOS rats. The metabolites in the ovarian tissues were analyzed by liquid chromatography with tandem mass spectrometry. RESULTS: PCOS rats showed an increased in body weight, levels of luteinizing hormone and testosterone and insulin resistance, which was significantly attenuated by the DM treatment. The DM treatment improved disrupted estrous cycle and increased the granulosa cells of the ovary in the PCOS rats. The decreased proliferation and increased cell apoptosis of granulosa cells in the ovarian tissues of PCOS rats were significantly reversed by the DM treatment. The analysis of metabolics revealed that ATP and lactate levels were significantly decreased in PCOS rats, which was recovered by the DM treatment. Furthermore, the expression of LDH-A, PKM2 and SIRT1 was significantly down-regulated in ovarian tissues of the PCOS rats; while the DM treatment significantly increased the expression of LDH-A, PKM2 and SIRT1 in the ovarian tissues of the PCOS rats. CONCLUSION: In conclusion, our study demonstrated that Diane-35 plus metformin treatment improved the pathological changes in the PCOS rats. Further studies suggest that Diane-35 plus metformin can improve the energy metabolism of the ovary via regulating the glycolysis pathway. The mechanistic studies indicated that the therapeutic effects of Diane-35 plus metformin treatment in the PCOS rats may be associated with the regulation of glycolysis-related mediators including PKM2, LDH-A and SIRT1.


Subject(s)
Androgen Antagonists/pharmacology , Cyproterone Acetate/pharmacology , Ethinyl Estradiol/pharmacology , Glycolysis/drug effects , Hypoglycemic Agents/pharmacology , Metformin/pharmacology , Ovulation/drug effects , Polycystic Ovary Syndrome/metabolism , Animals , Apoptosis/drug effects , Body Weight/drug effects , Disease Models, Animal , Drug Combinations , Drug Therapy, Combination , Female , Insulin Resistance , Lactate Dehydrogenase 5/drug effects , Lactate Dehydrogenase 5/metabolism , Luteinizing Hormone/drug effects , Luteinizing Hormone/metabolism , Ovary/drug effects , Ovary/metabolism , Pyruvate Kinase/drug effects , Pyruvate Kinase/metabolism , Rats , Sirtuin 1/drug effects , Sirtuin 1/metabolism , Testosterone/metabolism
2.
Blood ; 130(11): 1347-1356, 2017 09 14.
Article in English | MEDLINE | ID: mdl-28760888

ABSTRACT

Pyruvate kinase (PK) deficiency is a rare genetic disease that causes chronic hemolytic anemia. There are currently no targeted therapies for PK deficiency. Here, we describe the identification and characterization of AG-348, an allosteric activator of PK that is currently in clinical trials for the treatment of PK deficiency. We demonstrate that AG-348 can increase the activity of wild-type and mutant PK enzymes in biochemical assays and in patient red blood cells treated ex vivo. These data illustrate the potential for AG-348 to restore the glycolytic pathway activity in patients with PK deficiency and ultimately lead to clinical benefit.


Subject(s)
Enzyme Activators/pharmacology , Enzyme Activators/therapeutic use , Erythrocytes/enzymology , Pyruvate Kinase/deficiency , Pyruvate Kinase/metabolism , Quinolines/pharmacology , Quinolines/therapeutic use , Sulfonamides/pharmacology , Sulfonamides/therapeutic use , Anemia, Hemolytic, Congenital Nonspherocytic , Animals , Enzyme Activation/drug effects , Enzyme Activators/chemistry , Erythrocytes/drug effects , Humans , Kinetics , Mice , Piperazines , Pyruvate Kinase/drug effects , Pyruvate Metabolism, Inborn Errors , Quinolines/chemistry , Recombinant Proteins/metabolism , Sulfonamides/chemistry , Tissue Donors
3.
Microb Pathog ; 134: 103564, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31163248

ABSTRACT

Bacterial infections require special care since the indiscriminate use of antibiotics to treat them has been linked to the emergence of resistant strains. In this sense, phytoterapeutic alternatives such as curcumin and its nanocapsules have emerged as a promising supplement in optimizing availability of bioactives and reducing the development of antimicrobial resistance. Thus, the aim of this study was to verify the effects of pure and nanoencapsulated curcumin in the treatment of experimental listeriosis in gerbils regarding many aspects including antibacterial effect, antioxidant mechanisms involved and the energetic metabolism. Four groups were used containing 6 animals each: T0 (control), T1 (infected), T2 (infected and treated with free curcumin - dose of 30Ć¢Ā€ĀÆmg/kg/day) and T3 (infected and treated with nanocapsules containing curcumin - a dose of 3Ć¢Ā€ĀÆmg/kg/day). Treated animals received curcumin for 6 consecutive days starting 24Ć¢Ā€ĀÆh after Listeria monocytogenes infection. All animals were euthanized on the 12th day after L. monocytogenes infection. Quantitative polymerase chain reaction (qPCR) identified L. monocytogenes DNA in the spleens of all animals of the T1 group, as well as T2 (2 out of 6) and T3 (5 out of 6). The weight of the spleens confirmed the infection, since it was larger in the T1 group, differing statistically from T0, and similarly to T2 and T3. Hepatic histopathological examination showed mild infiltration of neutrophils and macrophages, except for the T3 group (only 1/6). In the liver, the pyruvate kinase activity was higher in T1 and T2 compared to T0 and T3. The adenylate kinase activity did not differ between groups. The Na+/K+ATPase activity was lower in T1 group compared to T0 and T3. Lipoperoxidation was lower in the T3 group compared to groups T0, T1 and T2. The antioxidant capacity against peroxyl radicals was higher in T1, T2 and T3 groups compared to T0. In conclusion, free curcumin showed potent antibacterial effects; however, the nanoencapsulated form was able to minimize the effects caused by L. monocytogenes regarding tissue injury, changes on enzymes of the energetic metabolism, in addition to an antioxidant effect against lipoperoxidation.


Subject(s)
Curcumin/administration & dosage , Curcumin/therapeutic use , Listeria monocytogenes/drug effects , Listeriosis/drug therapy , Listeriosis/veterinary , Nanocapsules/chemistry , Adenosine Triphosphatases , Adenylate Kinase/drug effects , Animals , Anti-Bacterial Agents/administration & dosage , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/therapeutic use , Antioxidants/pharmacology , Curcumin/chemistry , Dietary Supplements , Disease Models, Animal , Gerbillinae , Homeostasis/drug effects , Inflammation , Lipid Peroxidation/drug effects , Listeriosis/microbiology , Liver/pathology , Polymethacrylic Acids/chemistry , Polymethacrylic Acids/pharmacology , Polymethacrylic Acids/therapeutic use , Pyruvate Kinase/drug effects , Sodium-Potassium-Exchanging ATPase/drug effects , Spleen/pathology
4.
An Acad Bras Cienc ; 90(1): 99-108, 2018.
Article in English | MEDLINE | ID: mdl-29236866

ABSTRACT

Considering that thiol-containing enzymes like kinases are critical for several metabolic pathways and energy homeostasis, we investigated the effects of cystine dimethyl ester and/or cysteamine administration on kinases crucial for energy metabolism in the kidney of Wistar rats. Animals were injected twice a day with 1.6 Āµmol/g body weight cystine dimethyl ester and/or 0.26 Āµmol/g body weight cysteamine from the 16th to the 20th postpartum day and euthanized after 12 hours. Pyruvate kinase, adenylate kinase, creatine kinase activities and thiol/disulfide ratio were determined. Cystine dimethyl ester administration reduced thiol/disulfide ratio and inhibited the kinases activities. Cysteamine administration increased the thiol/disulfide ratio and co-administration with cystine dimethyl ester prevented the inhibition of the enzymes. Regression between the thiol/disulfide ratio, and the kinases activities were significant. These results suggest that redox status may regulate energy metabolism in the rat kidney. If thiol-containing enzymes inhibition and oxidative stress occur in patients with cystinosis, it is possible that lysosomal cystine depletion may not be the only beneficial effect of cysteamine administration, but also its antioxidant and thiol-protector effect.


Subject(s)
Cysteamine/pharmacology , Cystine/analogs & derivatives , Disulfides , Homeostasis/drug effects , Kidney/drug effects , Sulfhydryl Compounds , Adenylate Kinase/analysis , Adenylate Kinase/drug effects , Animals , Creatine Kinase/analysis , Creatine Kinase/drug effects , Cystine/pharmacology , Cystine Depleting Agents/pharmacology , Kidney/enzymology , Pyruvate Kinase/analysis , Pyruvate Kinase/drug effects , Random Allocation , Rats, Wistar , Reference Values , Reproducibility of Results
5.
FEBS Open Bio ; 14(5): 843-854, 2024 May.
Article in English | MEDLINE | ID: mdl-38514913

ABSTRACT

Glioblastoma (GBM) is a primary tumor in the central nervous system with poor prognosis. It exhibits elevated glucose uptake and lactate production. This metabolic state of aerobic glycolysis is known as the Warburg effect. N6-isopentenyladenosine (iPA), a natural cytokine modified with an isopentenyl moiety derived from the mevalonate pathway, has well-established anti-tumor activity. It inhibits cell proliferation in glioma cells, inducing cell death by apoptosis and/or necroptosis. In the present study, we found that iPA inhibits aerobic glycolysis in unmodified U87MG cells and in the same cell line engineered to over-express wild-type epidermal growth factor receptor (EGFR) or EGFR variant III (vIII), as well as in a primary GBM4 patient-derived cell line. The detection of glycolysis showed that iPA treatment suppressed ATP and lactate production. We also evaluated the response of iPA treatment in normal human astrocyte primary cells, healthy counterpart cells of the brain. Aerobic glycolysis in treated normal human astrocyte cells did not show significant changes compared to GBM cells. To determine the mechanism of iPA action on aerobic glycolysis, we investigated the expression of certain enzymes involved in this metabolic pathway. We observed that iPA reduced the expression of pyruvate kinase M2 (PKM2), which plays a key role in the regulation of aerobic glycolysis, promoting tumor cell proliferation. The reduction of PKM2 expression is a result of the inhibition of the inhibitor of nuclear factor kappa-B kinase subunit, beta/nuclear factor-kappa B pathway upon iPA treatment. In conclusion, these experimental results show that iPA may inhibit aerobic glycolysis of GBM in stabilized cell lines and primary GBM cells by targeting the expression and activity of PKM2.


Subject(s)
Glioblastoma , Glycolysis , Isopentenyladenosine , Pyruvate Kinase , Humans , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Brain Neoplasms/metabolism , Brain Neoplasms/pathology , Brain Neoplasms/drug therapy , Brain Neoplasms/genetics , Cell Line, Tumor , Cell Proliferation/drug effects , Glioblastoma/metabolism , Glioblastoma/pathology , Glioblastoma/drug therapy , Glioblastoma/genetics , Glycolysis/drug effects , Isopentenyladenosine/pharmacology , Isopentenyladenosine/metabolism , Pyruvate Kinase/drug effects , Pyruvate Kinase/metabolism
6.
Cell Transplant ; 30: 9636897211027524, 2021.
Article in English | MEDLINE | ID: mdl-34263655

ABSTRACT

Energy metabolism programming is a hallmark of cancer, and serves as a potent target of cancer therapy. Valproic acid (VPA), a broad Class I histone deacetylases (HDACs) inhibitor, has been used as a therapeutic agent for cancer. However, the detail mechanism about the potential role of VPA on the Warburg effect in breast cancer remains unclear. In this study, we highlight that VPA significantly attenuates the Warburg effect by decreasing the expression of pyruvate kinase M2 isoform (PKM2), leading to inhibited cell proliferation and reduced colony formation in breast cancer MCF-7 and MDA-MB-231 cells. Mechanistically, Warburg effect suppression triggered by VPA was mediated by inactivation of ERK1/2 phosphorylation through reduced HDAC1 expression, resulting in suppressing breast cancer growth. In summary, we uncover a novel mechanism of VPA in regulating the Warburg effect which is essential for developing the effective approach in breast cancer therapy.


Subject(s)
Anticonvulsants/therapeutic use , Breast Neoplasms/drug therapy , Protein Isoforms/drug effects , Pyruvate Kinase/drug effects , Valproic Acid/therapeutic use , Animals , Anticonvulsants/pharmacology , Cell Proliferation , Female , Humans , Mice , Mice, Nude , Valproic Acid/pharmacology
7.
J Diabetes Investig ; 12(5): 697-709, 2021 May.
Article in English | MEDLINE | ID: mdl-33314682

ABSTRACT

AIMS/INTRODUCTION: Tubulointerstitial fibrosis is a hallmark of diabetic nephropathy and is associated with an epithelial-to-mesenchymal transition (EMT) program and aberrant glycolysis. Dimeric pyruvate kinase (PK) M2 (PKM2) acts as a key protein kinase in aberrant glycolysis by promoting the accumulation of hypoxia-inducible factor (HIF)-1α, while tetrameric PKM2 functions as a pyruvate kinase in oxidative phosphorylation. The aim of the research is to study the effect of PKM2 tetramer activation on preventing kidney fibrosis via suppression of aberrant glycolysis and the EMT program. MATERIALS AND METHODS: In vivo: Streptozotocin (STZ) was utilized to induce diabetes in 8-week-old CD-1 mice; 4 weeks after diabetes induction, proteinuria-induced kidney fibrosis was developed by intraperitoneal injection of bovine serum albumin (BSA: 0.3Ā g/30Ā g BW) for 14Ā days; The PKM2 activator TEPP-46 was also administered orally simultaneously. In vitro: HK2 cells were co-treated with high-glucose media or/and TGF-Ɵ1 and TEPP46 for 48Ā h, cellular protein was extracted for evaluation. RESULTS: Diabetic mice developed kidney fibrosis associated with aberrant glycolysis and EMT; BSA injection accelerated kidney fibrosis in both the control and diabetic mice; TEPP-46 rescued the kidney fibrosis. In HK2 cells, TEPP-46 suppressed the EMT program induced by TGF-Ɵ1 and/or high-glucose incubation. TEPP-46-induced PKM2 tetramer formation and PK activity resulted in suppression of HIF-1α and lactate accumulation. Specific siRNA-mediated knockdown of HIF-1α expression diminished high glucose-induced mesenchymal protein levels. CONCLUSION: PKM2 activation could restore the tubular phenotype via suppression of the EMT program and aberrant glycolysis, providing an alternative target to mitigate fibrosis in diabetic kidneys.


Subject(s)
Diabetes Mellitus, Experimental/complications , Diabetic Nephropathies/prevention & control , Epithelial-Mesenchymal Transition/drug effects , Glycolysis/drug effects , Pyridazines/pharmacology , Pyrroles/pharmacology , Animals , Diabetes Mellitus, Experimental/chemically induced , Fibrosis , Hypoxia-Inducible Factor 1, alpha Subunit/drug effects , Kidney/pathology , Mice , Oxidative Phosphorylation/drug effects , Pyruvate Kinase/drug effects , Streptozocin
8.
Biomolecules ; 11(5)2021 04 28.
Article in English | MEDLINE | ID: mdl-33925206

ABSTRACT

The Warburg effect has been considered a potential therapeutic target to fight against cancer progression. In KRAS mutant cells, PKM2 (pyruvate kinase isozyme M2) is hyper-activated, and it induces GLUT1 expression; therefore, KRAS has been closely involved in the initiation of Warburg metabolism. Although mTOR (mammalian target of rapamycin), a well-known inhibitor of autophagy-dependent survival in physiological conditions, is also activated in KRAS mutants, many recent studies have revealed that autophagy becomes hyper-active in KRAS mutant cancer cells. In the present study, a mathematical model was built containing the main elements of the regulatory network in KRAS mutant cancer cells to explore the further possible therapeutic strategies. Our dynamical analysis suggests that the downregulation of KRAS, mTOR and autophagy are crucial in anti-cancer therapy. PKM2 has been assumed to be the key switch in the stress response mechanism. We predicted that the addition of both pharmacologic ascorbate and chloroquine is able to block both KRAS and mTOR pathways: in this case, no GLUT1 expression is observed, meanwhile autophagy, essential for KRAS mutant cancer cells, is blocked. Corresponding to our system biological analysis, this combined pharmacologic ascorbate and chloroquine treatment in KRAS mutant cancers might be a therapeutic approach in anti-cancer therapies.


Subject(s)
Chloroquine/pharmacology , Neoplasms/metabolism , Proto-Oncogene Proteins p21(ras)/genetics , Antineoplastic Agents/pharmacology , Autophagy/drug effects , Models, Theoretical , Neoplasms/drug therapy , Proto-Oncogene Proteins p21(ras)/metabolism , Pyruvate Kinase/drug effects , Pyruvate Kinase/metabolism , Signal Transduction/drug effects , Sirolimus/pharmacology , TOR Serine-Threonine Kinases/metabolism , Warburg Effect, Oncologic/drug effects
9.
Trends Endocrinol Metab ; 31(6): 393-395, 2020 06.
Article in English | MEDLINE | ID: mdl-32340764

ABSTRACT

Angiari et al. recently reported that TEPP-46 induces PKM2 tetramerization, thereby inhibiting its nuclear translocation and suppressing CD4+ T cell activation, T helper (Th)1/Th17 cell development, and experimental autoimmune encephalomyelitis (EAE) development both in vitro and in vivo. Moreover, TEPP-46 suppresses T cell glycolysis. These findings identify PKM2 tetramerization as a potential therapeutic target.


Subject(s)
CD4-Positive T-Lymphocytes/drug effects , Encephalomyelitis, Autoimmune, Experimental/etiology , Pyridazines/pharmacology , Pyrroles/pharmacology , Pyruvate Kinase/chemistry , Pyruvate Kinase/drug effects , Th1 Cells/drug effects , Th17 Cells/drug effects , Animals , Humans
10.
Sci Rep ; 8(1): 8323, 2018 05 29.
Article in English | MEDLINE | ID: mdl-29844464

ABSTRACT

Warburg effect is an emerging hallmark of cancer cells with pyruvate kinase M2 (PKM2) as its key regulator. Curcumin is an extensively-studied anti-cancer compound, however, its role in affecting cancer metabolism remains poorly understood. Herein, we show that curcumin inhibits glucose uptake and lactate production (Warburg effect) in a variety of cancer cell lines by down-regulating PKM2 expression, via inhibition of mTOR-HIF1α axis. Stable PKM2 silencing revealed that PKM2 is required for Warburg effect and proliferation of cancer cells. PKM2 over-expression abrogated the effects of curcumin, demonstrating that inhibition of Warburg effect by curcumin is PKM2-mediated. High PKM2 expression correlated strongly with poor overall survival in cancer, suggesting the requirement of PKM2 in cancer progression. The study unravels novel PKM2-mediated inhibitory effect of curcumin on metabolic capacities of cancer cells. To the best of our knowledge, this is the first study linking curcumin with PKM2-driven cancer glycolysis, thus, providing new perspectives into the mechanism of its anticancer activity.


Subject(s)
Curcumin/metabolism , Pyruvate Kinase/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Curcumin/pharmacology , Down-Regulation , Gene Expression Regulation, Neoplastic/genetics , Glycolysis/drug effects , HEK293 Cells , HeLa Cells , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , MCF-7 Cells , Pyruvate Kinase/metabolism , TOR Serine-Threonine Kinases/metabolism
11.
Int J Dev Neurosci ; 23(6): 509-14, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16023820

ABSTRACT

Considering that pyruvate kinase activity, a crucial enzyme for glucose metabolism and energy liberation in brain, may be regulated by some amino acids, it is possible that diminution of this enzyme activity may contribute to the brain damage caused by amino acids accumulated in metabolic diseases, such as phenylalanine, tryptophan and cystine. Therefore, the present study was undertaken to investigate the effect of these amino acids on pyruvate kinase activity in the brain cortex of rats. We also investigated the effect of serine and alanine on pyruvate kinase activity in the same tissue. The results suggested that phenylalanine, tryptophan, cystine, alanine, and serine act at the same site on the enzyme, phenylalanine, tryptophan, and cystine causing inhibition, and alanine and serine preventing this effect. Cystine also inhibited the enzyme activity through a different mechanism, possibly acting on the enzyme thiol groups. Considering that this enzyme is a target for amino acids accumulated in some metabolic diseases of amino acid metabolism, it is possible that its inhibition may contribute to the brain damage found in these diseases.


Subject(s)
Amino Acids/metabolism , Cerebral Cortex/enzymology , Energy Metabolism/physiology , Pyruvate Kinase/metabolism , Amino Acid Metabolism, Inborn Errors/metabolism , Amino Acid Metabolism, Inborn Errors/physiopathology , Amino Acids/pharmacology , Animals , Binding Sites/drug effects , Binding Sites/physiology , Brain Diseases, Metabolic, Inborn/metabolism , Brain Diseases, Metabolic, Inborn/physiopathology , Cerebral Cortex/drug effects , Cystine/metabolism , Cystine/pharmacology , Energy Metabolism/drug effects , Feedback, Physiological/drug effects , Feedback, Physiological/physiology , Nerve Degeneration/etiology , Nerve Degeneration/metabolism , Nerve Degeneration/physiopathology , Phenylalanine/metabolism , Phenylalanine/pharmacology , Pyruvate Kinase/drug effects , Rats , Rats, Wistar , Serine/metabolism , Serine/pharmacology , Tryptophan/metabolism , Tryptophan/pharmacology
12.
FEBS Lett ; 403(1): 87-90, 1997 Feb 10.
Article in English | MEDLINE | ID: mdl-9038366

ABSTRACT

Resting rat thymocytes partially degrade glucose aerobically to CO2 and H2O and produce reactive peroxide anions. In contrast proliferating cells, due to enhanced induction of glycolytic enzymes, degrade glucose almost completely to lactate thus minimizing the production of reactive oxygen species. In this paper we show that under conditions of oxidative stress the induction of the glycolytic enzymes in cultured rat thymocytes is markedly reduced. Furthermore, transfection assays with a rat hepatoma cell line and Drosophila Schneider cells revealed that reactive oxygen intermediates dramatically decrease the transcriptional activities of the Sp1-dependent aldolase A and pyruvate kinase M2 promoters leading to reduced reporter gene expression. These results indicate that cellular redox changes can regulate gene expression by reversible oxidative inactivation of Sp1 binding.


Subject(s)
Oxidants/pharmacology , Sp1 Transcription Factor/metabolism , Thymus Gland/cytology , Thymus Gland/enzymology , Animals , Cell Division/drug effects , Cells, Cultured , Concanavalin A/pharmacology , DNA/metabolism , Enzyme Activation/drug effects , Female , Fructose-Bisphosphate Aldolase/drug effects , Fructose-Bisphosphate Aldolase/genetics , Fructose-Bisphosphate Aldolase/metabolism , Gene Expression Regulation , Hydrogen Peroxide/pharmacology , L-Lactate Dehydrogenase/drug effects , L-Lactate Dehydrogenase/genetics , L-Lactate Dehydrogenase/metabolism , Oxidation-Reduction , Oxidative Stress , Pyruvate Kinase/drug effects , Pyruvate Kinase/genetics , Pyruvate Kinase/metabolism , Rats , Rats, Wistar , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Sp1 Transcription Factor/drug effects , Thymus Gland/drug effects , Transcription, Genetic/drug effects , Transfection
13.
Biotechniques ; 10(5): 656-62, 1991 May.
Article in English | MEDLINE | ID: mdl-1910783

ABSTRACT

The mass and activity recovery of eight different enzymes (two monomeric, six oligomeric) with molecular masses between 25,000 and 240,000 daltons were tested after HPLC separation on three different HPLC instruments (two with stainless steel and one with titanium flow paths). Most of the tested proteins are known to be sensitive to heavy metal ions. Eight wide pore, ion-exchange columns, two size-exclusion columns and two hydrophobic-interaction columns were used. Both stainless steel and glass column hardware were used in all three separation modes. The elution times were between 8 and 12 minutes. In almost all cases, the activity recovery was between 90% and 100% compared with a control sample incubated in the chromatographic elution buffer for the same time at the same temperature. A severe activity loss (about 30%) was observed with only one ion-exchange column and one enzyme. Neither the column hardware nor the material of the HPLC equipment had any negative effect on the activity recovery of the enzymes tested.


Subject(s)
Chromatography, High Pressure Liquid/methods , Enzymes/isolation & purification , Alcohol Dehydrogenase/drug effects , Alcohol Dehydrogenase/isolation & purification , Catalase/drug effects , Catalase/isolation & purification , Chromatography, Gel , Chromatography, High Pressure Liquid/instrumentation , Chromatography, Ion Exchange , Chymotrypsin/drug effects , Chymotrypsin/isolation & purification , Glucosephosphate Dehydrogenase/drug effects , Glucosephosphate Dehydrogenase/isolation & purification , Glucosidases/drug effects , Glucosidases/isolation & purification , Iron/pharmacology , L-Lactate Dehydrogenase/drug effects , L-Lactate Dehydrogenase/isolation & purification , Pyruvate Kinase/drug effects , Pyruvate Kinase/isolation & purification , Time Factors , Zinc/pharmacology
14.
Br J Pharmacol ; 126(2): 467-77, 1999 Jan.
Article in English | MEDLINE | ID: mdl-10077240

ABSTRACT

1. Vanadium compounds can mimic actions of insulin through alternative signalling pathways. The effects of three organic vanadium compounds were studied in non-ketotic, streptozotocin-diabetic rats: vanadyl acetylacetonate (VAc), vanadyl 3-ethylacetylacetonate (VEt), and bis(maltolato)oxovanadium (VM). A simple inorganic vanadium salt, vanadyl sulphate (VS) was also studied. 2. Oral administration of the three organic vanadium compounds (125 mg vanadium element 1(-1) in drinking fluids) for up to 3 months induced a faster and larger fall in glycemia (VAc being the most potent) than VS. Glucosuria and tolerance to a glucose load were improved accordingly. 3. Activities and mRNA levels of key glycolytic enzymes (glucokinase and L-type pyruvate kinase) which are suppressed in the diabetic liver, were restored by vanadium treatment. The organic forms showed greater efficacy than VS, especially VAc. 4. VAc rats exhibited the highest levels of plasma or tissue vanadium, most likely due to a greater intestinal absorption. However, VAc retained its potency when given as a single i.p. injection to diabetic rats. Moreover, there was no relationship between plasma or tissue vanadium levels and any parameters of glucose homeostasis and hepatic glucose metabolism. Thus, these data suggest that differences in potency between compounds are due to differences in their insulin-like properties. 5. There was no marked toxicity observed on hepatic or renal function. However, diarrhoea occurred in 50% of rats chronically treated with VS, but not in those receiving the organic compounds. 6. In conclusion, organic vanadium compounds, in particular VAc, correct the hyperglycemia and impaired hepatic glycolysis of diabetic rats more safely and potently than VS. This is not simply due to improved intestinal absorption, indicating more potent insulin-like properties.


Subject(s)
Glucose/metabolism , Ligands , Vanadium Compounds/pharmacology , Administration, Oral , Animals , Blood Glucose/drug effects , Blood Glucose/metabolism , Body Weight/drug effects , Diabetes Mellitus, Experimental/metabolism , Disinfectants/pharmacology , Glucokinase/drug effects , Glucokinase/genetics , Glucokinase/metabolism , Hydroxybutyrates/chemistry , Hydroxybutyrates/pharmacology , Hypoglycemic Agents/pharmacology , Injections, Intraperitoneal , Insulin/metabolism , Islets of Langerhans/drug effects , Islets of Langerhans/metabolism , Liver/drug effects , Liver/metabolism , Liver Glycogen/metabolism , Male , Muscles/drug effects , Muscles/metabolism , Organometallic Compounds/pharmacology , Pentanones/chemistry , Pentanones/pharmacology , Phosphoenolpyruvate Carboxykinase (GTP)/drug effects , Phosphoenolpyruvate Carboxykinase (GTP)/genetics , Phosphoenolpyruvate Carboxykinase (GTP)/metabolism , Pyrones/chemistry , Pyrones/pharmacology , Pyruvate Kinase/drug effects , Pyruvate Kinase/genetics , Pyruvate Kinase/metabolism , RNA, Messenger/drug effects , RNA, Messenger/genetics , Rats , Rats, Wistar , Time Factors , Vanadates/chemistry , Vanadates/pharmacology , Vanadium Compounds/chemistry
15.
Mol Cell Endocrinol ; 115(2): 141-8, 1995 Dec 29.
Article in English | MEDLINE | ID: mdl-8824889

ABSTRACT

This study tested the hypothesis that 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) plays a role in regulating some aspects of metabolism in IMR-90 normal human fetal lung fibroblasts. Among the enzymes studied, only pyruvate kinase showed a significant increase after treatment of confluent-phase cells with 1,25(OH)2D3 at various concentrations (0.1-100 nM range) for 24 h. A parallel increase in lactate output was observed. Steroid specificity was established by the failure of 10 nM levels of 25-hydroxyvitamin D3, estradiol-17 beta and progesterone to affect pyruvate kinase activity. The determination of the time course of [3H]-2-deoxy-D-glucose transport indicated that the hormone did not influence the transmembrane transport system of D-glucose. The addition of the inhibitors cycloheximide and actinomycin D to the culture medium abolished, at least in part, the 1,25(OH)2D3 stimulation of pyruvate kinase activity, suggesting the probable dependence of the hormone effect on cellular RNA and protein synthesis. 1,25(OH)2D3 also affected fibroblast growth and DNA synthesis. Cell number significantly decreased after 2-5 days treatment with 10 nM hormone in comparison with control fibroblasts, and also the incorporation of [3H]thymidine into DNA decreased after treatment of the cells with 1 and 10 nM hormone for 48 h. In conclusion, these data demonstrate that 1,25(OH)2D3 stimulates pyruvate kinase activity in confluent-phase IMR-90 human fibroblasts by a mechanism probably dependent on de novo protein synthesis, and also affects cell growth and DNA synthesis in sub-confluent-phase cells.


Subject(s)
Calcitriol/pharmacology , Growth Inhibitors/pharmacology , Pyruvate Kinase/drug effects , Biological Transport , Calcitriol/antagonists & inhibitors , Cell Division/drug effects , DNA/biosynthesis , Fetus , Fibroblasts/cytology , Fibroblasts/drug effects , Fibroblasts/metabolism , Glucose/metabolism , Growth Inhibitors/antagonists & inhibitors , Humans , Lactic Acid/metabolism , Lung/cytology , Lung/drug effects , Lung/metabolism , Pyruvate Kinase/metabolism
16.
J Nutr Biochem ; 15(8): 485-92, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15302084

ABSTRACT

This study was performed to determine the effects of dietary perilla oil, a n-3 alpha-linolenic acid (ALA) source, on hepatic lipogenesis as a possible mechanism of lowering triacylglycerol (TG) levels. Male Sprague-Dawley rats were trained for a 3-hour feeding protocol and fed one of five semipurified diets as follows: 1% (w/w) corn oil control diet, or one of four diets supplemented with 10% each of beef tallow, corn oil, perilla oil, and fish oil. Two separate experiments were performed to compare the effects of feeding periods, 4 weeks and 4 days. Hepatic and plasma TG levels were decreased in rats fed perilla oil and fish oil diets, compared with corn oil and beef tallow diets. The activities of hepatic lipogenic enzymes such as fatty acid synthase (FAS), glucose-6-phosphate dehydrogenase, and malic enzyme were suppressed in the fish oil, perilla oil, and corn oil-fed groups, and the effect was the most significant in the fish oil-fed group. Also, the activities of glycolytic enzymes, glucokinase, and L-pyruvate kinase showed the similar trend as that of lipogenic enzymes. The activity of FAS, the key regulatory enzyme in lipogenesis, was positively correlated with hepatic and plasma TG levels and reduced significantly in the perilla oil-fed group compared with corn oil-fed group. In addition, the FAS activity was negatively correlated with the hepatic microsomal content of EPA and DHA. In conclusion, suppression of FAS plays a significant role in the hypolipidemic effects observed in rats fed ALA rich perilla oil and these effects were associated with the increase of hepatic microsomal EPA and DHA contents.


Subject(s)
Fatty Acid Synthases/drug effects , Liver/enzymology , Plant Oils/pharmacology , Triglycerides/blood , alpha-Linolenic Acid/pharmacology , Animals , Body Weight/drug effects , Cell Membrane/chemistry , Cell Membrane/drug effects , Corn Oil/pharmacology , Dietary Fats/pharmacology , Eating/drug effects , Fatty Acid Synthases/genetics , Fatty Acid Synthases/metabolism , Fatty Acids/analysis , Fish Oils/pharmacology , Gene Expression Regulation/drug effects , Glucokinase/drug effects , Glucokinase/metabolism , Liver/drug effects , Male , Pyruvate Kinase/drug effects , Pyruvate Kinase/metabolism , Rats , Rats, Sprague-Dawley
17.
Life Sci ; 50(23): PL203-8, 1992.
Article in English | MEDLINE | ID: mdl-1317934

ABSTRACT

The effects of two representative sulfonylureas, tolbutamide and glyburide, on pyruvate kinase (PK) flux were examined in fasted rat hepatocytes. PK flux was estimated by trapping 14C from NaH14CO3 in a 2 mM lactate pool, accounting for any incomplete trapping by parallel incubations with L-[1-14C]alanine. Glyburide (20 microM) and tolbutamide (1 mM) decreased glucose formation by 34.9% and 54.8%, respectively, from 2 mM lactate. This decrease in glucose formation was associated with a proportional decrease in pyruvate carboxylase (PCOX) flux (32.7% and 50.5%, respectively). Under these conditions, no net change in PK flux was observed. When hepatocytes were preincubated with lactate and/or sulfonylurea addition for 30 min prior to radiolabeling with NaH14CO3, the metabolic state of the cells changed markedly. Glyburide produced a 34.6% decrease in glucose formation and a 31.3% decrease in PCOX flux, but no change in PK flux. In contrast, tolbutamide decreased glucose formation by 12.5% and increased PK flux by 53.2%, but no change in PCOX flux was observed. Such an increase in PK flux may be linked to tolbutamide-mediated increases in fructose-1,6-bisphosphate (F16P) via fructose-2,6-bisphosphate (F26P). These findings demonstrate that tolbutamide and glyburide decrease hepatic glucose production through various alterations in carbohydrate metabolism, depending upon the metabolic state of the cell. In addition, F26P may play a larger role in the hypoglycemic mechanism of action of tolbutamide than glyburide, since pyruvate carboxylase accounted for most of the decrease in glucose formation observed with glyburide and because preincubation with tolbutamide resulted in an activation of PK.


Subject(s)
Glyburide/pharmacology , Liver/enzymology , Pyruvate Kinase/metabolism , Tolbutamide/pharmacology , Animals , Bicarbonates/metabolism , Carbon Radioisotopes , Glucose/biosynthesis , Lactates/metabolism , Lactates/pharmacology , Liver/cytology , Liver/drug effects , Male , Pyruvate Kinase/drug effects , Rats , Rats, Inbred Strains , Sensitivity and Specificity , Sodium/metabolism , Sodium Bicarbonate , Sulfonylurea Compounds/pharmacology , Time Factors
18.
Comp Biochem Physiol B Biochem Mol Biol ; 134(3): 425-33, 2003 Mar.
Article in English | MEDLINE | ID: mdl-12628374

ABSTRACT

Pyruvate kinase type M(2) from Morris hepatoma 7777 tumour cell nuclei and cytosol, in contrast to types L and M(2) from nuclei and cytosol of normal rat liver, shows the histone H(1) kinase activity. Moreover, in the presence of L-cysteine and without ADP it converts 2-phosphoenolpyruvate (PEP) to pyruvate while in the presence of L-arginine or L-histidine does not. L-Cysteine markedly stimulates the activity of histone H(1) kinase transferring a phosphate group from PEP to, as results suggested, the epsilon -amino group of L-lysine of histone H(1). This, L-cysteine which is known to inhibit the activity of pyruvate kinase type M(2) from neoplastic cells transfering a phosphate from PEP to ADP, can act as a control factor champing the direction of enzymatic reaction in cancer cells.


Subject(s)
Liver Neoplasms, Experimental/enzymology , Liver/enzymology , Pyruvate Kinase/metabolism , Adenosine Triphosphate/pharmacology , Animals , Arginine/pharmacology , Cell Fractionation , Chromatin/isolation & purification , Chromatin/metabolism , Cysteine/pharmacology , Cytosol/enzymology , Electrophoresis, Polyacrylamide Gel , Enzyme Inhibitors/pharmacology , Histidine/pharmacology , Isoenzymes/chemistry , Isoenzymes/drug effects , Isoenzymes/metabolism , Phosphoenolpyruvate/pharmacology , Pyruvate Kinase/chemistry , Pyruvate Kinase/drug effects , Rats , Rats, Inbred BUF
19.
Article in English | MEDLINE | ID: mdl-9640602

ABSTRACT

In Thailand, the most common cause of chronic hemolytic anemia is thalassemia hemoglobinopathy. We report here a 10-year-old girl with pyruvate kinase (PK) deficiency who was initially diagnosed to have Hb H disease, like her sister. The patient had a history of neonatal jaundice which required blood exchange transfusion twice and phototherapy. She became anemic and regular blood transfusion was required since the age of 2 1/2 months. She was very anemic compared to her sister and was transfusion dependent. Besides, she never had red cell inclusion bodies, thus re-evaluation was performed. The diagnosis of red cell pyruvate kinase deficiency and the exclusion of Hb H disease was achieved after cessation of blood transfusion for 3 months. The family study also confirmed the diagnosis. The patient is now on high transfusion and iron chelation. She is doing well with mild splenomegaly.


Subject(s)
Pyruvate Kinase/drug effects , alpha-Thalassemia/epidemiology , Child , Erythrocytes/enzymology , Family , Female , Humans , Thailand/epidemiology
20.
Indian J Exp Biol ; 30(1): 8-11, 1992 Jan.
Article in English | MEDLINE | ID: mdl-1387111

ABSTRACT

Effects of prolactin (PRL), bromocriptine (Br), testosterone propionate (TP), dihydrotestosterone (DHT) and the combinations of these androgens with PRL/Br on the specific activities of caudal and cranial prostatic cellular enzymes involved in carbohydrate metabolism in castrated mature bonnet monkeys have been studied. Castration decreased all the enzymes studied such as hexokinase (HK), 6-phosphofructokinase (6-PFK), glyceraldehyde-3-phosphate dehydrogenase (G-3-PD), pyruvate kinase (PK), glucose-6-phosphate dehydrogenase (G-6-PD) and 6-phosphogluconate dehydrogenase (6-PGD) in the cranial and caudal prostates. PRL elevated the activities of all the enzymes above normal except G-3-PD of cranial lobe. In the caudal lobe, PRL brought back the activities of HK, PFK, PK, G-6-PD to normal and 6-PGD above normal except G-3-PD. TP/DHT treatment increased all the enzymes in both the lobes. PRL given along with TP/DHT further enhanced the androgen action with regard to HK, PK, G-6-PD and 6-PGD of cranial and PFK, G-3-PD, PK, G-6-PD and 6-PGD of caudal lobe. Br treatment did not produce any alteration of these enzymes in both the lobes. In the cranial lobe, during Br+TP/DHT treatment, the stimulating effects of androgen were unaffected on all the enzymes except PK. On the other hand in the caudal, the stimulatory effects of androgens were affected and the activities of HK, PFK, PK and 6-PGD were significantly decreased. The present results suggest that PRL has a direct as well as a synergistic action with androgens on enzymes of EMP and HMP shunt in the prostates of monkeys.


Subject(s)
Androgens/pharmacology , Carbohydrate Metabolism , Prolactin/pharmacology , Prostate/enzymology , Animals , Castration , Glucosephosphate Dehydrogenase/drug effects , Glyceraldehyde-3-Phosphate Dehydrogenases/drug effects , Hexokinase/drug effects , Macaca radiata , Male , Phosphofructokinase-1/drug effects , Phosphogluconate Dehydrogenase/drug effects , Prostate/drug effects , Prostate/metabolism , Pyruvate Kinase/drug effects
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