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1.
Folia Biol (Praha) ; 61(1): 1-7, 2015.
Article in English | MEDLINE | ID: mdl-25958305

ABSTRACT

Acyclic nucleoside phosphonates (ANPs) are potent antiviral agents effective against replication of DNA viruses and retroviruses including human immunodeficiency virus (HIV). Prototype compound 9-(R)-[2-(phosphonomethoxy)propyl]adenine (tenofovir) is a principal component of drugs widely used in the treatment of HIV infection (Viread, Truvada). Besides their antimetabolic mode of action, ANPs possess immunomodulatory properties. A number of them have been previously found to stimulate secretion of cytokines and anti-HIV effective chemokines. In the present pilot experiments we analysed the in vitro effects of ANPs on the expression of chemokine receptors CCR5 and CXCR4 that are co-receptors of HIV-1 entry in cells. The impact of ANPs was investigated at the level of gene transcription of mRNA in mouse lymphocytes and macrophages using the RT-PCR method. The following compounds were included in the study: 9-(R)-[2-(phosphonomethoxy) propyl]adenine (tenofovir), N6-cyclopropyl-(R)- 9-[2-(phosphonomethoxy)-propyl]2,6-diaminopurine, N6-cyclopentyl-(R)-9-[2-(phosphonomethoxy) propyl]2,6-diaminopurine, N6-dimethylaminoethyl-(R)-9-[2-(phosphonomethoxy)propyl]2,6-diaminopurine, N6-cyclopentyl-9-[2-(phosphonomethoxy) ethyl]2,6-diaminopurine, N6-isobutyl-9-[2-(phosphonomethoxy) ethyl]2,6-diaminopurine. Gene transcription of chemokine receptors CCR5 and CXCR4 was not affected after application of these acyclic nucleoside phosphonate antivirals.


Subject(s)
Antiviral Agents/pharmacology , Gene Expression Regulation/drug effects , Nucleosides/pharmacology , Receptors, CCR5/genetics , Receptors, CXCR4/genetics , Animals , Antiviral Agents/chemistry , Female , Lymphocytes/drug effects , Lymphocytes/metabolism , Mice, Inbred C57BL , Nucleosides/chemistry , RNA, Messenger/genetics , RNA, Messenger/metabolism , Receptors, CCR5/metabolism , Receptors, CXCR4/metabolism
2.
Folia Microbiol (Praha) ; 55(2): 181-9, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20490762

ABSTRACT

Effects of Gram-negative probiotic E. coli strain Nissle 1917 (EcN) on the production of nitric oxide (NO) and cytokines were determined in cultures of resident peritoneal cells of rats. The cells (2 x 10(6)/mL) were cultured for 24 h in the presence of live EcN suspension (EcN-Susp), bacteria-free supernatant of this suspension (Sup-EcN), and LPS of EcN origin (LPS-EcN). The biosynthesis of NO was substantially enhanced using live bacteria counts as low as 10(3)/mL applied in the form of EcN-Susp. The same NO-enhancing effect was produced by the correspondingly diluted Sup-EcN. It was found that Sup-EcN contained relatively high amounts of LPS. Administration of the LPS-EcN mimicked the high NO-augmenting activities of both Sup-EcN and EcN-Susp. However, the activity of LPS-EcN was significantly less pronounced than were the activities of Sup-EcN and EcN-Susp containing identical amounts of LPS. The NO-stimulatory effects of the EcN preparations were completely inhibited by polymyxin B. All LPS-EcN and correspondingly diluted Sup-EcN and EcN-Susp stimulated the secretion of cytokines TNF-alpha, IL-1beta, IL-6, IL-10 and VEGF. Also these effects were abrogated by polymyxin B. In contrast to the effects on NO production, the cytokine-stimulatory effects were significantly less pronounced after the exposure of the cells to Sup-EcN and EcN-Susp than to the identical amounts of LPS-EcN. It may be concluded that the in vitro stimulatory effects of EcN on NO and cytokine production are mediated by LPS. It is suggested that the immunostimulatory activity of LPS is modulated by EcN-derived factor(s), the nature of which remains to be identified.


Subject(s)
Bacterial Infections/immunology , Cytokines/immunology , Escherichia coli/immunology , Lipopolysaccharides/immunology , Nitric Oxide/immunology , Probiotics , Animals , Bacterial Infections/microbiology , Cells, Cultured , Disease Models, Animal , Escherichia coli/metabolism , Female , Humans , Lipopolysaccharides/metabolism , Peritoneal Cavity/cytology , Peritoneal Cavity/microbiology , Rats , Rats, Wistar
3.
Br J Pharmacol ; 157(3): 342-61, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19371342

ABSTRACT

The major concern of pharmacology about cytokines has originated from plentiful data showing association between gross changes in their production and pathophysiological processes. Despite the enigmatic role of cytokines in diseases, a number of them have become a subject of cytokine and anti-cytokine immunotherapies. Production of cytokines can be influenced by many endogenous and exogenous stimuli including drugs. Cells of the immune system, such as macrophages and lymphocytes, are richly endowed with receptors for the mediators of physiological functions, such as biogenic amines, adenosine, prostanoids, steroids, etc. Drugs, agonists or antagonists of these receptors can directly or indirectly up- and down-regulate secretion of cytokines and expression of cytokine receptors. Vice versa, cytokines interfere with drug pharmacokinetics and pharmacodynamics through the interactions with cytochrome P450 and multiple drug resistance proteins. The aim of the review is to encourage more intensive studies in these fields of cytokine pharmacology. It also outlines major areas of searching promising candidates for immunotherapeutic interventions.


Subject(s)
Cytokines/biosynthesis , Animals , Cytochrome P-450 Enzyme System/metabolism , Cytokines/antagonists & inhibitors , Cytokines/genetics , Cytokines/immunology , Drug Discovery , Drug Resistance , Gene Expression Regulation , Humans , Immunotherapy , Lymphocytes/drug effects , Lymphocytes/immunology , Lymphocytes/metabolism , Macrophages/drug effects , Macrophages/immunology , Macrophages/metabolism , Pharmacokinetics , Pharmacology , Receptors, Cytokine/antagonists & inhibitors , Receptors, Cytokine/biosynthesis , Signal Transduction , Toll-Like Receptors/agonists , Toll-Like Receptors/physiology
4.
Physiol Res ; 57(5): 761-768, 2008.
Article in English | MEDLINE | ID: mdl-17949244

ABSTRACT

The total content of rat liver microsomal cytochrome P450 (CYP) significantly decreased after repeated i.p. administration of the antiviral agent tenofovir ((R)-9-[2-(phosphonomethoxy)propyl] adenine) and tenofovir disoproxil at a daily dose 25 mg/kg, although the content of liver microsomal protein did not change. The decrease of the CYP content was accompanied by concomitant increase of the amount of inactive CYP form, cytochrome P420. This effect was confirmed by a parallel study of the activities of selected CYP forms, CYP2E1 (p-nitrophenol hydroxylation) and CYP1A2 (7-ethoxyresorufin deethylation). The activity (expressed relatively to the protein content) of both CYP forms decreased significantly following the decrease of the total CYP. On the other hand, the CYP2E1 activity expressed relatively to the decreasing total CYP content remained unchanged. However, CYP1A2 activity also decreased when calculated relatively to the total native CYP content indicating lower stability of this form. Semiquantitative RT-PCR showed no significant changes in expression of major rat liver microsomal CYP forms after tenofovir treatment. In conclusion, repeated administration of tenofovir in higher doses led to significant decrease of the relative proportion of active liver microsomal CYPs accompanied by a conversion of these enzymes to the inactive form (CYP420) maintaining the sum of CYP proteins unchanged.


Subject(s)
Adenine/analogs & derivatives , Antiviral Agents/pharmacology , Cytochrome P-450 CYP1A2/metabolism , Cytochrome P-450 CYP2E1/metabolism , Liver/drug effects , Organophosphonates/pharmacology , Prodrugs/pharmacology , Adenine/administration & dosage , Adenine/pharmacology , Animals , Antiviral Agents/administration & dosage , Cytochrome P-450 CYP1A2/genetics , Cytochrome P-450 CYP2E1/genetics , Cytochromes/metabolism , Down-Regulation , Female , Injections, Intraperitoneal , Liver/enzymology , Microsomes, Liver , Organophosphonates/administration & dosage , Prodrugs/administration & dosage , Protein Denaturation , RNA, Messenger/metabolism , Rats , Rats, Inbred Lew , Tenofovir
5.
Physiol Res ; 57(4): 569-575, 2008.
Article in English | MEDLINE | ID: mdl-17705667

ABSTRACT

Glucagon and alpha-adrenergic-induced glycogenolysis is realized via the agonist/adenylyl cyclase/cAMP/protein kinase signaling pathway or via the activation of phosphorylase kinase by the mobilized calcium that supports the inhibition of glycogen synthase, respectively. The role of nitric oxide (NO) in this process has not been extensively studied. The present work was directed to the question whether NO is produced during glucagon-induced glycogenolysis in rat hepatocyte in a similar way like alpha-adrenoceptor stimulation. Glycogen-rich hepatocyte cultures were used. NO production (NO(2)(-)) was assessed under the influence of glucagon, dibutyryl cyclic AMP (db-cAMP), forskolin, the nitric oxide synthase (NOS) inhibitors N(omega)-nitro-L-arginine methyl ester (L-NAME) and aminoguanidine, and the NO donor S-nitroso-N-acetyl penicillamine (SNAP). Inducible NOS (iNOS) mRNA was examined by reverse transcription-polymerase chain reaction. Glycogenolysis was followed up by estimation of medium glucose levels. The amount of glucose and NO(2)(-) released by glycogen-rich hepatocytes was increased as a result of glucagon, db-cAMP, forskolin and SNAP treatments. iNOS gene expression was upregulated by glucagon. Glycogenolysis that occurs through glucagon receptor stimulation involves NO production downstream of transduction pathways through an isoform of NO synthase. The present and previous studies document possible involvement of NO signaling in glycogenolytic response to glucagon and adrenergic agonists in hepatocytes.


Subject(s)
Glucagon/pharmacology , Glucose/metabolism , Hepatocytes/metabolism , Nitric Oxide/physiology , Signal Transduction/drug effects , Animals , Bucladesine/pharmacology , Cell Separation , Cells, Cultured , Colforsin/pharmacology , Glycogen/biosynthesis , Guanidines/pharmacology , Hepatocytes/drug effects , Male , Nitric Oxide/biosynthesis , Nitric Oxide Donors/pharmacology , Nitric Oxide Synthase Type II/antagonists & inhibitors , Nitric Oxide Synthase Type II/biosynthesis , Nitric Oxide Synthase Type II/metabolism , Rats , Rats, Wistar , Reverse Transcriptase Polymerase Chain Reaction , S-Nitroso-N-Acetylpenicillamine/pharmacology
6.
Cell Biol Toxicol ; 23(5): 337-54, 2007 Sep.
Article in English | MEDLINE | ID: mdl-17447015

ABSTRACT

Increased cytosolic calcium ([Ca2+]i) and nitric oxide (NO) are suggested to be associated with apoptosis that is a main feature of many liver diseases and is characterized by biochemical and morphological features. We sought to investigate the events of increase in [Ca2+]i and endoplasmic reticulum (ER) calcium depletion by thapsigargin (TG), a selective inhibitor of sarco-ER-Ca2+ -ATPases, in relation to NO production and apoptotic and necrotic markers of cell death in primary rat hepatocyte culture. Cultured hepatocytes were treated with TG (1 and 5 micromol/L) for 0-24 or 24-48 h. NO production and inducible NO synthase (iNOS) expression were determined as nitrite levels and by iNOS-specific antibody, respectively. Hepatocyte apoptosis was estimated by caspase-3 activity, cytosolic cytochrome c content and DNA fragmentation, and morphologically using Annexin-V/propidium iodide staining. Hepatocyte viability and mitochondrial activity were evaluated by ALT leakage and MTT test. Increasing basal [Ca2+]i by TG, NO production and apoptotic/necrotic parameters were altered in different ways, depending on TG concentration and incubation time. During 0-24 h, TG dose-dependently decreased iNOS-mediated spontaneous NO production and simultaneously enhanced hepatocyte apoptosis. In addition, TG 5 micromol/L produced secondary necrosis. During 24-48 h, TG dose-dependently enhanced basal NO production and rate of necrosis. TG 5 micromol/L further promoted mitochondrial damage as demonstrated by cytochrome c release. A selective iNOS inhibitor, aminoguanidine, suppressed TG-stimulated NO production and ALT leakage from hepatocytes after 24-48 h. Our data suggest that the extent of the [Ca2+]i increase and the modulation of NO production due to TG treatment contribute to hepatocyte apoptotic and/or necrotic events.


Subject(s)
Apoptosis/physiology , Hepatocytes/physiology , Nitric Oxide/biosynthesis , Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism , Thapsigargin/pharmacology , Animals , Apoptosis/drug effects , Calcium/physiology , Caspase 3/metabolism , Cell Death/drug effects , Cell Nucleus/drug effects , Cell Nucleus/physiology , Cells, Cultured , Guanidines/pharmacology , Hepatocytes/drug effects , Mitochondria/drug effects , Mitochondria/physiology , Nitric Oxide Synthase Type II/antagonists & inhibitors , Nitric Oxide Synthase Type II/metabolism , Rats , Sarcoplasmic Reticulum Calcium-Transporting ATPases/antagonists & inhibitors
7.
Physiol Res ; 56(4): 419-425, 2007.
Article in English | MEDLINE | ID: mdl-16925470

ABSTRACT

Certain liver metabolic diseases point to the presence of disturbances in glycogen deposition. Epinephrine raises the cAMP level that activates protein kinase A leading to the activation of phosphorylase and glycogen breakdown. In the present report, we sought to investigate whether NO is produced during adrenoceptor agonist-induced glycogenolysis in rat hepatocytes in cultures. Isolated glycogen rich rat hepatocytes in cultures were used. NO production (NO(2)(-)) was assessed under the effect of adrenergic agonists and adrenergic agonist/antagonist pairs, dibutyryl cyclic AMP sodium-potassium salt (db-cAMP), NO synthase (NOS) inhibitors N(omega)-nitro-L-arginine methyl ester (L-NAME), aminoguanidine (AG) and the NO donor S-nitroso-N-acetyl penicillamine (SNAP). The inducible NO synthase (iNOS) mRNA was examined by the reverse transcription-polymerase chain reaction (RT-PCR). Glycogenolysis was quantified by glucose levels released into medium. The amount of glucose and NO(2)(-) released by hepatocytes was increased as a result of epinephrine, phenylephrine or db-cAMP treatments. The increase in glucose and NO(2)(-) released by epinephrine or phenylephrine was blocked or reduced by prazosin pretreatment and by NOS inhibitors aminoguanidine and L-NAME. iNOS gene expression was up-regulated by epinephrine. It can be concluded that glycogenolysis occurs through -adrenoceptor stimulation and a signaling cascade may involve NO production.


Subject(s)
Adrenergic alpha-Agonists/pharmacology , Epinephrine/metabolism , Glycogenolysis/drug effects , Hepatocytes/drug effects , Nitric Oxide Synthase Type II/biosynthesis , Nitric Oxide/metabolism , Phenylephrine/pharmacology , Receptors, Adrenergic/drug effects , Adrenergic alpha-Antagonists/pharmacology , Animals , Cells, Cultured , Cyclic CMP/analogs & derivatives , Cyclic CMP/pharmacology , Enzyme Induction , Enzyme Inhibitors/pharmacology , Glucose/metabolism , Guanidines/pharmacology , Hepatocytes/enzymology , Hepatocytes/metabolism , Male , NG-Nitroarginine Methyl Ester/pharmacology , Nitric Oxide Donors/pharmacology , Nitric Oxide Synthase Type II/antagonists & inhibitors , Prazosin/pharmacology , Rats , Rats, Wistar , Receptors, Adrenergic/metabolism , S-Nitroso-N-Acetylpenicillamine/pharmacology , Time Factors
8.
Xenobiotica ; 36(12): 1165-77, 2006 Dec.
Article in English | MEDLINE | ID: mdl-17162464

ABSTRACT

Adefovir (PMEA) and tenofovir (PMPA) and their prodrugs, adefovir dipivoxil (bisPOM-PMEA) and tenofovir disoproxil (bisPOC-PMPA), were subjected to a detailed study of their potential to inhibit the activities of human liver microsomal cytochromes P450 (CYP). The inhibition of marker enzyme activities of CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2D6, CYP2E1 and CYP3A4 was examined with high-performance liquid chromatography (HPLC) or spectroscopic (fluorescence, luminescence) detection. Adefovir and adefovir dipivoxil did not significantly influence activities of most CYP enzymes. The activity of CYP3A4 was inhibited by adefovir dipivoxil at concentrations over 100 microM. Adefovir and its prodrug inhibited CYP2C9 at concentrations below 100 microM; inhibition by adefovir was of the uncompetitive (at the lower inhibitor concentrations) or of the competitive nature with a Ki = 420 microM. Tenofovir and tenofovir disoproxil influenced the activity of CYP2C9, and competitive inhibition was found with Ki = 580 and 395 microM, respectively. Tenofovir disoproxil was shown to inhibit microsomal CYP2E1 activities by a mixed-type inhibition with Ki values at about 140 microM. The results indicate the possibility of an influence of the compounds tested on the respective CYP activities when used at high doses.


Subject(s)
Adenine/analogs & derivatives , Antiviral Agents/adverse effects , Cytochrome P-450 Enzyme Inhibitors , Microsomes, Liver/drug effects , Microsomes, Liver/enzymology , Organophosphonates/adverse effects , Adenine/adverse effects , Enzyme Inhibitors/adverse effects , Female , Humans , In Vitro Techniques , Kinetics , Male , Prodrugs/adverse effects , Tenofovir
9.
Histol Histopathol ; 20(2): 467-73, 2005 04.
Article in English | MEDLINE | ID: mdl-15736051

ABSTRACT

Until now, the role of nitric oxide (NO) in cornea irradiated with UVB rays remains unknown. Therefore, we investigated nitric oxide synthase isomers (NOS), enzymes that generate NO, nitrotyrosine (NT), a cytotoxic byproduct of NO, and malondialdehyde (MDA), a byproduct of lipid peroxidation, in rabbit corneas repeatedly irradiated with UVB rays (312 nm, 1x daily for 6 days, the dose per day 1.01 J/cm2) using immunohistochemical methods. The biochemical measurement of nitrite and nitrate has been used for the indirect investigation of NO concentration in the aqueous humor. Results show that in contrast to normal corneas, where of the NOS isomers only endothelial nitric oxide synthase (NOS3) was expressed in a significant amount (in the epithelium and endothelium), in irradiated corneas all NOS isomers (also brain nitric oxide synthase, NOS1, and inducible nitric oxide synthase, NOS2) as well as an indirect measure of ONOO-formation and MDA were gradually expressed, first in the epithelium, the endothelium and the keratocytes beneath the epithelium and finally in the cells of all corneal layers and the inflammatory cells that invaded the corneal stroma. This was accompanied by an elevated concentration of NO in the aqueous humor. In conclusion, repeated irradiation with UVB rays evoked the stimulation of NO production, peroxynitrite formation (demonstrated by NT residues) and lipid peroxidation (evaluated by MDA staining).


Subject(s)
Cornea/metabolism , Cornea/radiation effects , Nitric Oxide Synthase/metabolism , Reactive Nitrogen Species/biosynthesis , Tyrosine/analogs & derivatives , Ultraviolet Rays/adverse effects , Animals , Aqueous Humor/metabolism , Immunohistochemistry , Lipid Peroxidation/radiation effects , Malondialdehyde/metabolism , Nerve Tissue Proteins/metabolism , Nitric Oxide/biosynthesis , Nitric Oxide Synthase Type I , Nitric Oxide Synthase Type II , Nitric Oxide Synthase Type III , Peroxynitrous Acid/biosynthesis , Rabbits , Tyrosine/metabolism
10.
Cent Eur J Public Health ; 12 Suppl: S94-6, 2004 Mar.
Article in English | MEDLINE | ID: mdl-15141993

ABSTRACT

The paper describes expected and unexpected results gained from studies performed decades ago, and so to say - forgotten. 1. Different bacterial toxins can induce considerable changes in pharmacokinetics and pharmacodynamics of applied drugs. To admit clinical trials, only results from healthy human volunteers are required, however. 2. Antagonists to the toxicity of bacterial toxins in general have to be administered prior to the toxin. However, adenosine triphosphate (ATP) is effective also when applied after toxins. ATP is "in" again in contemporary research. 3. A controlled clinical trial revealed substantial differences between the D- and D,L-form of cycloserin. 4. The antimetabolite 6-azauracil riboside and eventually its triacetate derivative was claimed to possess antitumor properties. However, a controlled clinical trial did not confirm its potency in this aspect. On the other hand, the tolerance was excellent. This finding encouraged clinical trials in psoriasis, a disease of autoimmune etiology. Moreover, beneficial effects and tolerance of the compound was described in herpes zoster and even in smallpox. On the basis of these results a controlled clinical trial in rheumatoid arthritis, also judged to be an autoimmune disease, was started. Because of early high toxicity, the study was discontinued. 5. High doses of the compound induce ocular lesions in animals. The above examples justify the titel of this paper.


Subject(s)
Toxicology/trends , Animals , Controlled Clinical Trials as Topic , Humans
11.
Folia Microbiol (Praha) ; 49(6): 737-44, 2004.
Article in English | MEDLINE | ID: mdl-15881412

ABSTRACT

Due to a gene defect (Lps(d)), C3H/HeJ mice are known to be hyporesponsive to the immunobiological potential of lipopolysaccharide (LPS). We studied dose requirements for LPS, IFN-gamma, and cytokines TNF-alpha and IL-10 to produce nitric oxide (NO) in peritoneal macrophages (Mphi) from these animals. In contrast to the Lps(n) C3H/HeN mice, high concentrations of LPS (up to 5 microg/mL) or IFN-gamma (up to 5 ng/mL) by themselves were unable to activate NO production in C3H/HeJ Mphi. The failure to produce NO could not be overcome by addition of L-arginine or tetrahydropterin. The high-output NO biosynthesis was dose-dependently stimulated by combined administration of varying concentrations of IFN-gamma (50-5000 pg/mL) and LPS (approximately 1 ng/mL) or to a lesser extent by IFN-gamma plus TNF-alpha or TNF-alpha/IL-10. Formation of NO in C3H/HeJ MCO triggered by high concentration of LPS (approximately 1 microg/mL) given together with IFN-gamma (0.2-5 ng/mL) reached the values typical for Lps(n) C3H/HeN mice. While Mphi from C3H/HeN mice secreted TNF-alpha, IL-10, and IL-10 upon contact with a low dose of LPS (1 ng/mL), C3H/HeJ Mphi required high concentration of LPS (5 microg/mL) to enhance the secretion of the cytokines. Yet, this dose remained ineffective to stimulate IFN-gamma in Mphi from C3H/HeJ mice. It can be presumed that one of the important factors influencing their deficient ability to form NO is a failure of Mphi to produce IFN-gamma upon LPS contact.


Subject(s)
Cytokines/immunology , Lipopolysaccharides/immunology , Macrophage Activation/immunology , Macrophages, Peritoneal/immunology , Nitric Oxide/biosynthesis , Animals , Cytokines/biosynthesis , Cytokines/metabolism , Escherichia coli/immunology , Escherichia coli/metabolism , Female , Interferon-gamma/immunology , Interferon-gamma/metabolism , Interleukin-10/immunology , Interleukin-10/metabolism , Macrophages, Peritoneal/metabolism , Mice , Mice, Inbred C3H , Tumor Necrosis Factor-alpha/immunology , Tumor Necrosis Factor-alpha/metabolism
12.
Antimicrob Agents Chemother ; 45(12): 3381-6, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11709312

ABSTRACT

Development of a novel group of antiviral agents, acyclic nucleoside phosphonates, has provided a new perspective for treating human immunodeficiency virus (HIV) infection. One of the compounds, 9-(R)-[2-(phosphonomethoxy)propyl]adenine (PMPA) (tenofovir), has been shown to confer complete protection against AIDS in a simian model of the infection. The aim of our study was to investigate whether the antiviral efficacy of PMPA, which depends mainly on inhibition of virus-induced DNA polymerase or of reverse transcriptase, could be contributed by immunomodulatory potential of this drug. We screened for its ability to activate production of cytokines and chemokines that are known to interfere with the replication and/or the entry of HIV in cells. Using the in vitro test system of mouse macrophages and lymphocytes, it has been found that PMPA stimulates macrophage secretion of interleukin-1beta (IL-1beta), IL-10, and tumor necrosis factor alpha. Production of the chemokines RANTES and macrophage inflammatory protein 1alpha was activated in both macrophages and lymphocytes, and also in human cell line U937. Other cytokines--i.e., IL-2, IL-12, IL-13, and gamma interferon-remained uninfluenced by PMPA. The cytokines were stimulated in a dose-dependent fashion, with rapid onset, and peak concentrations were achieved within 5 to 24 h. The findings contribute to a more complex understanding of mechanisms of antiviral effectiveness of PMPA and support the view that this drug could become a promising candidate for therapeutic exploitation in anti-HIV preventive medicine.


Subject(s)
Adenine/analogs & derivatives , Adenine/pharmacology , Anti-HIV Agents/pharmacology , Chemokines/physiology , Cytokines/physiology , Organophosphonates , Organophosphorus Compounds/pharmacology , Animals , Cells, Cultured , Chemokine CCL4 , Chemokine CCL5/metabolism , Female , Interleukin-1/metabolism , Interleukin-10/metabolism , Macrophage Inflammatory Proteins/metabolism , Macrophages/drug effects , Macrophages/metabolism , Mice , Mice, Inbred C57BL , Tenofovir , Tumor Necrosis Factor-alpha/metabolism
13.
Eur Cytokine Netw ; 12(1): 22-32, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11282542

ABSTRACT

Enhanced levels of cyclic AMP (cAMP), resulting from stimulation of adenylyl cyclase through activation of distinct pharmacological receptor systems, have a remarkable impact on the activity of the immune system. Among other responses, production of nitric oxide (NO) is also affected. The effects of cAMP range from stimulation to inhibition (or no effect) of immune-stimulated biosynthesis of NO, with a preponderance of stimulatory interference. cAMP has been shown to be a potent, dual modulator of cytokine expression. It dose-dependently suppresses secretion of major NO up-regulatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). On the other hand, production of IL-10, which is known to regulate the inducible NO synthase (iNOS) activation in both a positive and negative direction, is inversely enhanced. It is suggested that the dual effects of cAMP on NO formation are likely to result from the differences in the concentration ratio of these cytokines. The value of this parameter depends on the type and concentration of cAMP-stable derivatives and cAMP-enhancing agents, such as prostaglandins, beta-adrenoceptor agonists, phosphodiesterase inhibitors, forskolin and cholera toxin. The cytokine ratio may be influenced by dynamically developing multiple down- and up-regulatory feedback circuits among cytokines, NO, and cAMP.


Subject(s)
Cyclic AMP/physiology , Cytokines/physiology , Nitric Oxide/biosynthesis , Adenosine/physiology , Animals
14.
Folia Microbiol (Praha) ; 46(4): 353-8, 2001.
Article in English | MEDLINE | ID: mdl-11830949

ABSTRACT

Reactive NO metabolites play a distinct role in the control of Salmonella enterica serovar Typhimurium (ST; a facultative intracellular pathogen) in susceptible host. A significant increase of nitrite and/or nitrate plasma levels, 3-nitro-tyrosine expression and pathological changes in mesenteric lymph nodes have been observed in gnotobiotic piglets orally infected for 1 d with a virulent strain of ST but not in piglets infected with a rough mutant of ST.


Subject(s)
Nitric Oxide/metabolism , Salmonella Infections, Animal/metabolism , Salmonella typhimurium/pathogenicity , Tyrosine/analogs & derivatives , Tyrosine/metabolism , Animals , Germ-Free Life , Immunoenzyme Techniques , Intestines/ultrastructure , Liver/ultrastructure , Lung/ultrastructure , Lymph Nodes/metabolism , Lymph Nodes/ultrastructure , Mesentery , Microscopy, Electron , Phagocytosis , Salmonella Infections, Animal/immunology , Salmonella Infections, Animal/microbiology , Salmonella Infections, Animal/pathology , Swine , Swine, Miniature , Virulence
15.
Pharmacogenetics ; 10(6): 493-501, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10975603

ABSTRACT

Quantitative aspects of the in-vitro interferon (IFN)-gamma-induced nitric oxide (NO) production by peritoneal macrophages of eight inbred strains of mice were investigated. Animals employed in the study can be assorted into three phenotype categories: high, moderate, and low NO-responders. Concentration of nitrites in the 24-h supernatants of cells stimulated with recombinant murine IFN-gamma (25 U/ml) reached the following values (mean +/- SEM; in microM): C57BL/10 (33.7+/-1.88) = C57BL/6 (32.1+/-2.10) > SIL (24.0+/-1.55) > CBA/J (18.1+/-1.79) = C3H/HeN (18.0+/-1.10) > DBA/2 (11.4+/-1.16) = DBA/1 (11.0+/-1.20) = Balb/c (11.0+/-1.16). Approximately 80% of the total variation was found to be controlled by genetic factors. No association between the extent of NO formation and variation in the constitutive expression of macrophage IFN-gamma receptor was observed. Similar magnitude of inter-strain differences was sustained after enhanced NO-stimulation of the cells with IFN-gamma + tumour necrosis factor (TNF)-alpha, but only high (strains BL/10, BL/6, SJL, CBA/J, C3H/HeN) and low (DBA/1, DBA/2, Balb/c) NO-responder phenotypes were detected after the triple cytokine cocktail composed of IFN-gamma + TNF-alpha + interleukin (IL)-10. The strain differences remained unchanged after the supplementation of culture medium with L-arginine or tetrahydrobipopterin. Genetically governed differences in IFN-gamma-induced NO production have been found to be tightly associated with differential expression of inducible nitric oxide synthase mRNA. Possible implications of the findings for various fields of NO biomedical research are discussed.


Subject(s)
Cytokines/pharmacology , Genetic Variation , Macrophages, Peritoneal/drug effects , Nitric Oxide/biosynthesis , Animals , Cytokines/biosynthesis , Macrophages, Peritoneal/metabolism , Mice , Mice, Inbred Strains , Species Specificity
16.
J Leukoc Biol ; 67(3): 312-8, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10733090

ABSTRACT

Macrophages play an important role in effector mechanisms of various chronic inflammatory diseases. We studied the effect of gluten, the agent inducing celiac disease, and other food antigens on the activation of macrophages. Nitric oxide (NO) and cytokine production were followed as markers of activation, using cultured murine peritoneal macrophages. None of the food antigens tested caused direct inducible nitric oxide synthase (iNOS) activation in macrophages. Unlike other food antigens gluten, gliadin, and their proteolytic fragments significantly enhanced NO production when applied together with interferon-gamma (IFN-gamma), the most efficient being fragments originating from 25- to 45-min peptic digestion. The activation pathway was mediated via direct stimulation of tumor necrosis factor alpha (TNF-alpha) secretion. The NO-enhancing effect was confirmed at the level of iNOS mRNA transcription. In case of sustained local inflammatory reaction connected with increase of IFN-gamma, gluten and its proteolytic fragments may thus elevate NO production. Increased NO level could consequently participate in the development of mucosal lesions in the gut of celiac patients.


Subject(s)
Antigens/immunology , Cytokines/biosynthesis , Food , Glutens/immunology , Macrophage Activation/immunology , Macrophages, Peritoneal/immunology , Nitric Oxide/metabolism , Animals , Cells, Cultured , Cytokines/immunology , Cytokines/metabolism , Female , Gliadin/chemical synthesis , Gliadin/immunology , Glutens/pharmacology , Interferon-gamma/immunology , Interleukin-10/biosynthesis , Interleukin-10/metabolism , Macrophages, Peritoneal/drug effects , Macrophages, Peritoneal/enzymology , Macrophages, Peritoneal/metabolism , Mice , Mice, Inbred BALB C , Mice, Inbred C3H , Nitric Oxide Synthase/genetics , Nitric Oxide Synthase Type II , Nitrites/metabolism , Peptide Fragments/chemical synthesis , Peptide Fragments/immunology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Transcriptional Activation/drug effects , Tumor Necrosis Factor-alpha/biosynthesis , Tumor Necrosis Factor-alpha/metabolism
17.
Toxicology ; 142(3): 179-88, 2000 Jan 17.
Article in English | MEDLINE | ID: mdl-10667889

ABSTRACT

Psychoneuroimmunology was for the first time comprehensively described about 20 years ago. The influence of mental status on the course and outcome of a number of diseases, however, was suspected a long time before. Also the links between mental affective disorders and the immune status were repeatedly suggested. The authors in this paper shortly reviewed the most important clinical as well as experimental evidence which at present strongly supports the concept of a close and bidirectional communication between central nervous, neuroendocrine and immune systems. The most important anatomical, physiological as well as pharmacological experimental data, which were obtained by the authors during 20 years of research in this field, are presented. The data strongly suggest that in the very next future we will not only better understand a very complex communication between mind and body, but also completely new types of compounds might become available.


Subject(s)
Immune System/physiology , Psychoneuroimmunology/trends , Animals , Forecasting , Humans , Neurosecretory Systems/immunology
18.
Int J Immunopharmacol ; 22(12): 1121-9, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11137619

ABSTRACT

Acyclic nucleoside phosphonates (ANPs) are potent broad-spectrum antivirals, also effective against immunodeficiency viruses and hepatitis viruses. Effects of several ANPs on in vitro cytokine gene expression and nitric oxide (NO) production by murine peritoneal macrophages were investigated. Included in the study were 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA; Adefovir), 9-(R)-[2-(phosphonomethoxy)propyl]adenine [(R)-PMPA; Tenofovir], 9-(S)-[2-(phosphonomethoxy)propyl]adenine; (S)-PMPA), 9-[2-(phosphonomethoxy)ethyl]-2,6-diaminopurine (PMEDAP), 9-(R)-[2-(phosphonomethoxy)propyl]-2,6-diaminopurine (PMPDAP), and 9-[2-(phosphonomethoxy)ethyl]guanine (PMEG). Some of them, i.e. (R)-PMPA, (S)-PMPA, and PMEG, stimulate secretion of TNF-alpha and IL-10 in a concentration-dependent manner, and enhance the IFN-gamma-induced secretion of TNF-alpha. Although unable to activate production of nitric oxide (NO) on their own, these compounds substantially augment NO formation induced by IFN-gamma. Analysis of the expression of inducible NO synthase mRNA indicates that the NO-enhancing effect of ANPs is mediated posttranscriptionally. In contrast to IFN-gamma, production of NO triggered by lipopolysaccharide (LPS) alone, or synergistically by LPS+IFN-gamma, remains unaltered by ANPs. The immunomodulatory effects have been differentially expressed in distinct genotypes of inbred strains of mice, including the low NO-responders Balb/c and high NO-responders C3H/HeN. Although less effectively, PMEG and (R)-PMPA also increase production of TNF-alpha and NO by the IFN-gamma- but not LPS-co-stimulated macrophages from C3H/HeJ mice, which are otherwise hypo-responsive to major immune stimuli provided by IFN-gamma and LPS. It can be concluded that the expression of immunomodulatory properties of ANPs depends on the immune state of cells and its activation by distinct priming signals.


Subject(s)
Adjuvants, Immunologic/pharmacology , Antiviral Agents/pharmacology , Macrophage Activation/drug effects , Nucleosides/pharmacology , Animals , Cytokines/metabolism , Female , Lipopolysaccharides/immunology , Lipopolysaccharides/pharmacology , Macrophages/drug effects , Macrophages/immunology , Mice , Mice, Inbred BALB C , Mice, Inbred C3H , Nitric Oxide/metabolism , Nitric Oxide Synthase/biosynthesis , Nitric Oxide Synthase Type II , Organophosphonates/pharmacology , Reverse Transcriptase Polymerase Chain Reaction , Tumor Necrosis Factor-alpha/metabolism
19.
Eur Cytokine Netw ; 10(3): 319-28, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10477388

ABSTRACT

Adenosine and cAMP are potent modulators of immune-triggered cytokine production. Their effects overlap with regard to the inhibition of the pro-inflammatory cytokines TNF-alpha, IFN-gamma, IL-12, and the stimulation of production of the major anti-inflammatory cytokine IL-10. They may tentatively be considered to be upregulators of the production of Th2 cytokines (IL-10, IL-6), but downregulators of the production of Th1 cytokines (IL-2 and IFN-gamma). Cytokines produced in common by Th0, Th1 and Th2 cells are affected as well, although the low quantity and heterogeneity of the contemporary experimental data do not allow unambiguous conclusions to be drawn. Nevertheless, IL-3, IL-4, MIP-1alpha/beta and GM-CSF have usually been found to be inhibited, IL-5 stimulated, while IL-1 remains largely unaffected by adenosine or cAMP. These effects, and in particular the inhibition of TNF-alpha and stimulation of IL-10 expression, might be of therapeutic value in a variety of pathophysiological conditions.


Subject(s)
Adenosine/metabolism , Cyclic AMP/metabolism , Cytokines/biosynthesis , Animals , Feedback , Humans
20.
Eur J Pharmacol ; 376(1-2): 91-100, 1999 Jul 02.
Article in English | MEDLINE | ID: mdl-10440094

ABSTRACT

Antiarthritic effects of two acyclic nucleoside phosphonates, 9-(2-phosphonomethoxyethyl)adenine (PMEA; Adefovir) and 9-(2-phosphonomethoxypropyl)adenine (PMPA), as well as their more bioavailable prodrugs, bis(pivaloyloxymethyl)ester of PMEA [bis(POM)-PMEA; Adefovir Dipivoxil] and bis(isopropyloxycarbonyloxymethyl)ester of PMPA [bis(POC)-PMPA], were investigated in a model of adjuvant-induced arthritis in Lewis rats. The drugs were injected subcutaneously at doses of 5-50 mg/kg. PMEA and its prodrug inhibited by > 80% arthritic paw swelling, splenomegaly and fibroadhesive perisplenitis. Both prophylactic and therapeutic dosing regimens were effective. Neither PMPA nor bis(POC)-PMPA suppressed development of arthritic lesions. Substantially reduced nitrite + nitrate levels were detected in serum and urine of PMEA-treated animals as compared to those of untreated diseased controls. Also, complete suppression of the disease-associated, greatly enhanced systemic levels of the chemokine, RANTES (regulated upon activation, normal T cell expressed and secreted), was observed in rats injected with PMEA. Additional in vitro studies showed that PMEA does not change, PMPA enhances, and both prodrugs inhibit the immune-activated NO production. Under the same conditions PMEA inhibits, while PMPA slightly stimulates, secretion of RANTES. Collectively, these data suggest that the in vivo-inhibited production of nitric oxide (NO) is a consequence rather than a mechanism of antiarthritic action of PMEA. Possible mechanisms for the anti-RANTES activity of PMEA remains to be firmly established.


Subject(s)
Adenine/analogs & derivatives , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Chemokine CCL5/biosynthesis , Nitric Oxide/biosynthesis , Organophosphonates , Adenine/pharmacology , Animals , Arthritis, Experimental/drug therapy , Arthritis, Experimental/metabolism , Arthritis, Experimental/pathology , Chemokine CCL5/blood , Female , Fibrosis , Macrophages, Peritoneal/drug effects , Macrophages, Peritoneal/metabolism , Nitric Oxide/blood , Nitric Oxide/urine , Organ Size/drug effects , Organophosphorus Compounds/pharmacology , Prodrugs/pharmacology , Rats , Rats, Inbred Lew , Spleen/pathology , Tenofovir
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