Biomedical subjects

M Maccarrone

Publications and source records attributed to M Maccarrone.

At least 73 records · Page 4Linked to original sources

PubMed1998

Natural polyamines inhibit soybean (Glycine max) lipoxygenase-1, but not the lipoxygenase-2 isozyme.

Natural polyamines are shown to inhibit dioxygenase activity of soybean lipoxygenase-1, but they were ineffective toward the lipoxygenase-2 isozyme. The inhibitory power was dependent on the number of basic groups in the molecule, in the order spermine > spermidine > cadaverine >/= putrescine. Both spermidine and spermine acted as uncompetitive inhibitors of lipoxygenase-1 with respect to linoleic acid, the inhibition constants being 2.70 and 0.80 mM, respectively. The inhibitory power apparently correlated with the radical-trapping ability of the polyamines. Spermidine and spermine also inhibited the co-oxidase and peroxidase activities of lipoxygenase-1 and were effective inhibitors of lipoxygenase activity in lentil root protoplasts.

Dose-Response Relationship, Drug↗

PubMed1998

Cytotoxic effect of HIV-1 coat glycoprotein gp120 on human neuroblastoma CHP100 cells involves activation of the arachidonate cascade.

HIV type-1 (HIV-1) coat glycoprotein gp120 causes necrotic death in human neuroblastoma CHP100 cells. Here, we investigated the possible role of the arachidonate cascade and membrane peroxidation in gp120-induced cell necrosis. It is shown that gp120 increases the intracellular concentrations of prostaglandin E2 and leukotriene B4 by up-regulating the activity and expression of the arachidonate-metabolizing enzymes prostaglandin H synthase and 5-lipoxygenase respectively. Consistent with this observation, selective inhibitors of prostaglandin H synthase (i.e. indomethacin) and 5-lipoxygenase (i.e. MK886 and caffeic acid) protected CHP100 cells against gp120-induced necrosis. Treatment with gp120 also enhanced membrane lipid peroxidation and this may be implicated in the execution of cell damage. Interestingly, incubation with exogenous nitric oxide (NO) mimicked the effects of gp120 on necrotic death of CHP100 cells and activation of prostaglandin H synthase and 5-lipoxygenase. This suggests that NO might participate in the mechanism by which gp120 activates the arachidonate cascade.

Arachidonate 5-Lipoxygenase↗

PubMed1998

Requirement for membrane lipid peroxidation in HIV-1 gp120-induced neuroblastoma cell death.

The HIV-1 envelope protein gp120 engenders Ca(2+)-mediated, excitotoxic damage of rodent neuronal and human neuroblastoma cells in culture. Here we report that human CHP100 neuroblastoma cells undergo early peroxidation of membrane lipids following a brief exposure to gp120. This effect is prevented by preincubating cell cultures with the 21-aminosteroid U-74389G, an inhibitor of membrane lipid peroxidation, which also rescues neuroblastoma cultures from gp120-induced cell death; conversely, no protection from cell death is observed when the 21-aminosteroid is added to neuroblastoma cultures after the induction of membrane lipid peroxidation by gp120. These data indicate that membrane lipid peroxidation has a causative role in the expression of cell death produced by the viral protein.

Antioxidants↗

PubMed1998

Cholesterol, but not its esters, triggers programmed cell death in human erythroleukemia K562 cells.

Cholesterol, its biosynthetic precursors and the cholesterol-lowering drug compactin were able to inhibit the growth of human erythroleukemia K562 cells. Compactin, farnesyldiphosphate and cholesterol were cytotoxic by the induction of apoptosis (programmed cell death, PCD). Compactin doubled the number of apoptotic cells compared to control numbers, whereas farnesyldiphosphate and cholesterol led to a fivefold increase in PCD over the control levels. At variance with cholesterol, cholesterol esters did not affect K562 cell viability and apoptotic body formation, regardless of chain length and degree of saturation. Compactin and farnesyldiphosphate reduced the membrane cholesterol content, thus increasing membrane fluidity. Conversely, cholesterol treatment reduced the membrane fluidity by increasing cholesterol content in the lipid bilayer. Unlike farnesyldiphosphate, the other cholesterol precursors and cholesterol esters were ineffective in increasing the cholesterol content and, thereby, the fluidity of cell membranes. Compactin and cholesterol precursors, apart from farnesyldiphosphate, did not affect the amount of the farnesylated proteins Ras and lamin B in the cytosolic and the membrane fractions of K562 cell extracts, whereas farnesyldiphosphate reduced the content of both proteins in both fractions. The level of lamin B in K562 cytosol and membranes was also reduced by cholesterol treatment, which did not significantly affect the amount of Ras. These findings highlight the role of cholesterol in promoting PCD.

Anticholesteremic Agents↗

PubMed1998

Induction of apoptosis by bleomycin in resting and cycling human lymphocytes.

Bleomycin induces DNA and chromosome breakage. The differential sensitivity to the drug has been used in vitro to identify individuals at high risk of developing tumours. However, there are limited reports on the ability of bleomycin to induce apoptosis. In this study we tested induction of apoptosis in human peripheral lymphocytes by bleomycin at different concentrations and different culture times using various parameters, such as nuclear fragmentation and DNA fragmentation, evaluated either in situ with terminal transferase and labelled nucleotides (TUNEL) or by flow cytometry analysis. We demonstrate that bleomycin induces apoptosis without previous permeabilization of the cell membrane. Cell death occurs mainly by apoptosis and not by necrosis, with significant alteration of membrane lipoperoxidation (evaluated by luminescence).

Adult↗

PubMed1998

Altered gravity modulates 5-lipoxygenase in human erythroleukemia K562 cells.

Mammalian lipoxygenases catalyse the first committed step in the so-called "arachidonate cascade", leading to the production of potent bioactive molecules, such as leukotrienes, lipoxins and hepoxilins. Leukotrienes interact with G protein-couple receptors involved in neuronal plasticity and T lymphocyte activation, lipoxins activate leukocytes, hepoxilines control the insulin release and stimulate the phospholipase C. Lipoxygenase (linoleate:oxygen oxidoreductase; E.C. 1.13.11.34; 5-LOX) are responsible for lymphocyte maturation and programmed death (apoptosis) of neuronal cells. Therefore, 5-LOX might be Space relevant, because among the most striking effects of Space enviroment are indeed those on T lymphocyte activation, neuronal cell growth and suspectedly apoptosis. In this study, the possible effects of the force of gravity on the activity and expression of 5-LOX have been investigated by subjecting human erythroleukemia K562 cells to simulated hypogravity or hypergravity.

Arachidonate 5-Lipoxygenase↗

PubMed1997

The effect of hydroxylation of linoleoyl amides on their cannabinomimetic properties.

As yet, the physiological significance of hydroxylation of anandamide and linoleoyl amides is unknown. Therefore, we investigated whether hydroxylation of ODNHEtOH and ODNH2 influences their binding abilities to the CB-1 receptor and whether it alters their reactivity towards a fatty acid amide hydrolase (FAAH) from rat brain. Neither the fatty acid amides nor their hydroxylated derivatives were able to displace the potent cannabinoid [3H]CP 55.940 from the CB-1 receptor (Ki > 1 microM). Hydroxylation of ODNHEtOH resulted in a strong reduction of the maximum rate of hydrolysis by a FAAH, but the affinity of FAAH for the substrate remained of the same order of magnitude. Hydroxylation of ODNH2 led to a decrease in the affinity of FAAH for the substrate, but its maximum rate of conversion was unaffected. Furthermore, hydroxylation of ODNHEtOH enhanced its capacity to inhibit competitively the hydrolysis of anandamide. The resulting prolonged lifetime of anandamide and other fatty acid amide derivatives may have a considerable impact on cellular signal transduction.

Amidohydrolases↗

PubMed1997

Nitric oxide donors activate the cyclo-oxygenase and peroxidase activities of prostaglandin H synthase.

Prostaglandin H synthase (PHS) is a dual enzyme with cyclo-oxygenase and peroxidase activities. The nitric oxide (NO) donors, sodium nitroprusside (SNP), S-nitroso-N-acetylpenicillamine (SNAP) and spermine NONOate (SPER/NO), activated both cyclo-oxygenase and peroxidase activities of PHS. SNP activated PHS by increasing Vmax without affecting Km, the activation constants being 1.0 mM for cyclo-oxygenase and 1.3 mM for peroxidase. Analysis of progress curves and absorption spectra of PHS suggested that NO released from SNP interacted with the heme at the active site of the enzyme. Moreover, SNP counteracted the peroxide-induced inactivation of PHS, suggesting that the interplay between the intracellular peroxide and NO is critical in tuning PHS activity in cells.

Enzyme Activation↗

PubMed1997

Ozone stress modulates amine oxidase and lipoxygenase expression in lentil (Lens culinaris) seedlings.

The effect of ozone stress on polyamine metabolism and membrane lipid peroxidation in lentil seedlings through the amine oxidase and lipoxygenase activity and expression has been investigated. Ozone is shown to control the expression of these enzymes at the transcriptional level, down-regulating the amine oxidase gene and up-regulating the lipoxygenase gene. The decrease of amine oxidase activity correlated with the increase of putrescine concentration in the ozone-treated plantlets, whereas the increase of lipoxygenase activity was paralleled by enhanced membrane lipid peroxidation. Finally, polyamines are shown to inhibit lipoxygenase activity in lentils.

Amine Oxidase (Copper-Containing)↗

PubMed1997

Involvement of 5-lipoxygenase in programmed cell death of cancer cells.

We investigated the involvement of 5-lipoxygenase activity in the early phases of programmed cell death (PCD) induced by H2O2 or retinoids in different human tumour cells (erythroleukaemia, neuroblastoma, melanoma). Apoptotic cells showed enhanced 5-lipoxygenase activity which was paralleled by decreased superoxide dismutase activity and increased light emission. Ultraweak luminescence, mainly due to membrane lipid peroxidation by lipoxygenase activation, increased in all cell lines tested within 10-15 min after induction of PCD, in a concentration and time-dependent manner. At the same time, we observed a significant increase in the intracellular steady state level of the 5-lipoxygenase metabolite leukotriene B4. Furthermore, 5-lipoxygenase metabolite 5-hydroxyeicosatetraenoic acid was able to induce PCD in all cell lines tested. Conversely, the general lipoxygenase inhibitor nordihydroguaiaretic acid and the selective 5-lipoxygenase inhibitor caffeic acid protected the different tumour cells from H2O2-induced PCD to a similar extent. These results show the activation of the 5-lipoxygenase pathway in PCD of three different cancer cell lines.

Journal Article↗

PubMed1996

Membrane modifications in human erythroleukemia K562 cells during induction of programmed cell death by transforming growth factor beta 1 or cisplatin.

Transforming growth factor beta 1 (TGF beta 1) and cisplatin induce apoptosis (programmed cell death, PCD) in human erythroleukemia K562 cells in an additive manner. After PCD was induced in K562 cells, analysis of phospholipid composition, fatty acids and cholesterol content in their membranes showed a decrease in phosphatidylethanolamine and an increase in phosphatidylserine, cardiolipin and phosphatidic acid. Moreover, cisplatin but not TGF beta 1 enhanced sphingomyeline levels in apoptotic cells, whereas TGF beta 1 increased the amount of linoleic acid and, more remarkably, of cholesterol. The combination TGF beta 1 + cisplatin produced membrane changes similar to those provoked by each inducer individually. Furthermore, the specific activities of 5-lipoxygenase and cytosolic phospholipase A2, both modulating the physical properties of membranes and membrane-lipid-mediated intracellular signalling, were enhanced by treatment with TGF beta 1 or TGF beta 1 + cisplatin. These findings highlight the profound changes in cell membranes during the biochemical events of the apoptotic pathway.

Apoptosis↗

PubMed1996

Nitric oxide-donor compounds inhibit lipoxygenase activity.

The nitric oxide (N0-releasing agents sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP) inhibit dioxygenase activity of lipoxygenase in human platelets and human CHP100 neuroblastoma cells, leading the latter to necrosis. The effect of both NO-donors on the dioxygenase reaction was investigated by using soybean lipoxygenase type II (LOX-2) as a model for the mammalian enzyme. SNP and SNAP were competitive inhibitors of LOX-2, with inhibition constants of 525 microM and 710 microM, respectively. Both compounds inactivated LOX-2 by reducing the catalytic iron to the inactive Fe(II) form and counteracted the H2O2-mediated activation of the LOX-2 catalyzed dioxygenase reaction. Similarly, the co-oxidative and per-oxidative activities of LOX-2 were also inhibited by the NO-releasing agents. These findings suggest that the biological role played by NO can be mediated, at least in part, by the inactivation of lipoxygenase, a key-enzyme for the arachidonic acid metabolism in human cells.

Blood Platelets↗

PubMed1995

Inhibition of lipoxygenase in lentil protoplasts by expression of antisense RNA.

A number of plasmids were constructed containing chimeric genes consisting of fragments of antisense-oriented lentil lipoxygenase cDNA. The different constructs were tested for their ability to lower lipoxygenase activity in lentil protoplasts. Plasmids containing a full length lentil lipoxygenase cDNA proved to be the most effective, reducing the activity of the target enzyme to 70% of the control value. On the other hand, the full length lentil lipoxygenase cDNA in the sense orientation yielded a 20% increase of lipoxygenase activity.

DNA, Complementary↗

PubMed1995

Modulation of soybean lipoxygenase expression and membrane oxidation by water deficit.

The modulation of the activity and expression of soybean lipoxygenases 1 (LOX-1) [Vliegenthart, J.F.G. and Veldink, G.A. (1982) in: Free Radicals in Biology (Pryor, W.A., Ed.) pp. 29-64, Academic Press, New York] and 2 (LOX-2) by water deficit (osmotic stress) has been investigated, by following gene expression at the transcriptional and translational levels. Osmotic stress enhanced the transcription of the genes of both isoenzymes, leading to increased levels of the corresponding mRNAs, protein contents and specific activities. Abscisic acid (ABA) did not mediate enhancement of LOX expression, but caused a decrease of LOX-2 activity and was ineffective on LOX-1. Water deficit also caused oxidative modification of soybean membrane pool lipids [Schmidt, W.E. and Ebel, J. (1987) Proc. Natl. Acad. Sci. USA 84, 4117-4121], attributable to the increase of conjugated hydroperoxides in the esterified fatty acids of the lipid bilayer.

Abscisic Acid↗

PubMed1995

Role of lipid peroxidation in electroporation-induced cell permeability.

Erythroleukemia K562 cells and lentil (Lens culinaris) root protoplasts have been subjected to pore-forming electric fields suitable for transfection experiments. Evidence is presented that the amount of hydroperoxides formed in cell membranes of both cell-types is a function of field strength applied. On the other hand, the electroporation-induced lipid peroxidation paralleled the enhancement of membrane permeability and was associated with greater membrane fluidity. The membrane hydroperoxides formed upon electric shock enhanced cell luminescence, and lipoxygenase activity appeared to be involved in the process. Electroporation of prokaryotic cells of Escherichia coli also enhanced light emission, which was higher in lipoxygenase-expressing clones.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1995

Exogenously added copper does not increase the production of copper amine oxidase in lentil seedlings.

The effect of copper ions, the inorganic cofactor of amine oxidase (AO; EC 1.4.3.6), on the production of this enzyme in lentil (Lens culinaris) seedlings was studied. The addition of CuSO4 to the imbibition water during the germination of lentils increased the AO activity. However, the amounts of specific mRNA and protein were not affected by the presence of Cu2+. Furthermore, the addition of Cu2+ to homogenates of lentil seedlings grown in the absence of the metal substantially increased the AO activity. Therefore, it appears that exogenously added Cu2+ does not increase the production of AO in lentil seedlings which are still able to synthesize the copper-free enzyme. The addition of Cu2+ seems to reconstitute the enzymatically active holoprotein.

Amine Oxidase (Copper-Containing)↗

PubMed1995

Lentil root protoplasts: a transient expression system suitable for coelectroporation of monoclonal antibodies and plasmid molecules.

Protoplasts were isolated from lentil (Lens culinaris) roots and their suitability as a transient expression system was investigated. After transfecting the protoplasts with the beta-glucuronidase (GUS) gene by either electroporation or polyethylene glycol (PEG), the specific activity of the reporter enzyme and the cell viability were determined. Electroporation was more effective than PEG treatment as transfection procedure and its efficiency was affected by the plasmid length. The feasibility of electro-transferring at the same time (coelectroporation) inhibitory anti-lipoxygenase monoclonal antibodies and the GUS-carrying plasmid pBI 221 was investigated as well. The amount of transferred immunoglobulins was quantitated by ELISA and the inhibitory ability of monoclonal antibodies on the intracellular target enzyme was determined. Evidence is presented for the successful coelectroporation of immunoglobulins and plasmid DNA into lentil protoplasts, the two types of macromolecules acting independently of each other in the recipient cells.

Antibodies, Monoclonal↗

PubMed1995

Electroporation enhances cell membrane peroxidation and luminescence.

Electroporation is a most popular method of cell membrane permeabilization, by pulsed electric fields. It allows foreign molecules to enter the cell and has been used for many biotechnological applications, including transformation of mammalian cells and plant protoplasts by exogenous genetic material. However, the mechanism underlying membrane electropermeabilization is still largely unknown. Evidence is presented here that electroporation under conditions compatible with cell survival induces lipid hydroperoxide formation in the membranes of animal and plant cells. Exposure to electric fields also enhanced up to 5-fold the spontaneous emission of light from both cell types, which paralleled the amount of conjugated hydroperoxides detected in cell membranes. The emitted photons were mainly in the red edge of the spectrum, suggesting the involvement of singlet oxygen. The presence of antioxidants during electroporation did not reduce the formation of hydroperoxides nor the permeability but quenched the luminescence.

Antioxidants↗