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Biomedical subjects

J W Nyce

Publications and source records attributed to J W Nyce.

At least 19 recordsLinked to original sources
PubMed2001

Absorption, distribution, metabolism, and excretion of a respirable antisense oligonucleotide for asthma.

EPI-2010 is a respirable antisense oligonucleotide (RASON), which selectively attenuates discordantly overexpressed adenosine A(1) receptors in allergic lung (Nature 1997;385:721). In the present study, aerosolized [(35)S]-labeled EPI-2010 (5 mg exposure; specific activity 0.055 Ci/mmol) was administered to normal rabbits by endotracheal tube to assess biodistribution, route of elimination, and potential cardiovascular toxicity. The animals were killed at 0, 6, 24, 48, and 72 h after inhalation of EPI-2010. Duplicate aliquots from different tissues and samples were solubilized and assessed for radioactivity. Approximately 1.4% of the total aerosolized EPI-2010 was deposited into the lung. The concentration of the drug in the lung at 0, 6, 24, 48, and 72 h was 64.0 +/- 1.5, 67.0 +/- 4.4, 32.0 +/- 3.7, 23.4 +/- 1.4, and 2.1 +/- 0.5 microg equivalents, respectively. Only a small amount of the radioactivity was detected in extrapulmonary tissues. By 72 h, 67.5% of the administered dose was excreted in the urine, which represented the major pathway of elimination. In postlabeling studies, intact full-length EPI-2010 could only be detected in the lung. Autoradiographic analysis after inhalation of [(35)S]-labeled EPI-2010 showed a relatively uniform deposition of drug throughout the lung. The aerosolized EPI-2010 did not have any significant systemic effects on the cardiovascular system as determined by Cardiomax-II analysis. This pattern of distribution and the lack of effect on cardiovascular function support the concept that RASONs offer the potential to safely address respiratory targets for which systemic distribution and systemic bioavailability may be contraindicated.

Administration, Inhalation↗
PubMed2001

RASONs: a novel antisense oligonucleotide therapeutic approach for asthma.

Inhalation based approaches enable the local delivery of antisense oligonucleotides (ASONs) to the respiratory tract and thus facilitate the ability of ASONs to target and modulate the activity of discordantly expressed respiratory disease genes. Studies involving EPI-2010, a respirable antisense oligonucleotide (RASON), targeting the adenosine A(1) receptor, a G-protein-coupled-receptor (GPCR) that plays an important role in the aetiology of asthma, demonstrate that ASON therapeutics can be delivered directly to the lung as an aerosol. EPI-2010 has been shown to inhibit adenosine A(1) receptor expression and significantly improve allergen-induced airway obstruction and bronchial hyper-responsiveness in animal models of human asthma. Absorption, tissue distribution, metabolism and excretion (ADME) and safety studies of aerosolised EPI-2010 suggest that phosphorothioate RASONs can be delivered to target respiratory tissues in low, safe, efficacious and long-acting doses. This supports the concept that RASONs offer the potential to address a variety of respiratory targets including those for which approaches employing systemic distribution and systemic bioavailability of the therapeutic agent may be undesirable. In addition, our studies with EPI-2010 indicate that the RASON approach may represent a technology that is uniquely positioned to address the challenges of the post-genome era in respiratory drug discovery, since it enables simultaneous in vivo target validation and antisense therapeutic discovery in an accelerated timeframe.

Adenosine↗
PubMed2000

Respirable antisense oligonucleotides: a new drug class for respiratory disease.

Respirable antisense oligonucleotides (RASONs), which attenuate specific disease-associated mRNAs, represent a new class of respiratory therapeutics with considerable potential. RASONs overcome previous obstacles that have impeded the development of antisense therapeutics targeting diseases in other organ systems. RASONs are delivered directly to the target tissue via inhalation; their uptake seems to be enhanced by cationic properties inherent in pulmonary surfactant, and, because of the markedly different target properties of mRNA and proteins, they can have very long durations of effect compared with traditional drugs targeting the protein of the same gene. RASONs contain chemical modifications that decrease their degradation by cellular nucleases. However, total insensitivity to nucleases is probably not an optimal design criterion for RASONs, because moderate nuclease sensitivity can prevent their systemic delivery, decreasing the potential for systemic toxicity. EPI-2010 is a 21-mer phosphorothioate RASON that attenuates bronchoconstriction, inflammation and surfactant depletion in preclinical models of human asthma, has a duration of effect of seven days, and seems to undergo minimal systemic delivery.

Administration, Inhalation↗
PubMed1999

Autoradiographic evidence that intrastriatal administration of adenosine A(1) receptor antisense oligodeoxynucleotide decreases adenosine A(1) receptors in the rat striatum and cortex.

In this study, the effect of a phosphorothioated A(1) adenosine receptor antisense oligodeoxynucleotide on A(1) receptor density and mRNA in the striatum and cortex of rats was determined. Receptor autoradiography and in situ hybridization revealed a reduction in striatal and cortical A(1) receptor density and cortical A(1) receptor mRNA, respectively, in antisense-treated brains but not in those treated with a mismatch oligonucleotide. There was no change in A(2) receptor binding. These data imply that the corticostriatal pathway synthesizes A(1) receptors and transports them to its terminals.

Adenosine↗
PubMed1999

Oligonucleotide therapy of allergic asthma.

The recent increase in the prevalence of and mortality from asthma has inspired several new molecular techniques to improve treatment. Because asthma is a disease of gene polymorphism, gene therapy is unlikely to be effective. Alternative methods use oligonucleotides (ODNs) in the form of (1) DNA vaccination expressing CpG motifs that mimic bacterial DNA or (2) antisense ODNs inhaled and locally deposited into pulmonary airways to specifically modulate receptors for inflammatory mediators. DNA vaccination, a form of "molecular immune surveillance," attenuates a TH2 predominance. Antisense directed against the adenosine A(1 ) receptor abrogates A(1 ) sensitivity, improves allergen-induced immediate airway obstruction, and inhibits the expected increase in histamine responsiveness in allergic rabbits. Adenosine receptor inhibition lasts for an average of 7 days and the majority of the antisense remains in the lung. ODN therapy for asthma seem unlimited, but confirmation awaits the extension from animal models to human studies.

Animals↗
PubMed1999

Insight into adenosine receptor function using antisense and gene-knockout approaches.

The extensive role of adenosine in discriminating input from the extracellular environment is effected through a series of cell membrane-spanning proteins--the adenosine A1, A2A, A2B and A3 receptors. New genetic and epigenetic tools have emerged that facilitate the elucidation of the function of these receptors with greater specificity than is generally possible with traditional antagonist drugs. These tools include antisense oligonucleotides (epigenetic) and gene 'knockin' and 'knockout' mice (genetic) and are discussed in this article by Jonathan Nyce.

Animals↗
PubMed1997

Intrastriatal adenosine A1 receptor antisense oligodeoxynucleotide blocks ethanol-induced motor incoordination.

Intrastriatal administration of a 21-mer phosphorothioate antisense oligodeoxynucleotide targeting the adenosine A1 receptor blocked ethanol-induced motor incoordination in the rat and reduced striatal adenosine A1 receptor content, as judged by specific binding of the A1-specific ligand 8-cyclopentyl-1,3-dipropylxanthine (Bmax = 0.350 +/- 0.07, Kd = 1.87 +/- 0.50 nM). No effect upon striatal adenosine A2 receptor content was observed (Bmax = 0.415 +/- 0.04, Kd = 13.13 +/- 1.25 nM) with the A2-specific ligand 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine. A mismatched control oligodeoxynucleotide of identical G-C base composition and general sequence structure was without effect on adenosine A1 receptor (Bmax = 0.666 +/- 0.11, Kd = 1.32 +/- 0.27 nM) or adenosine A2 receptor content (Bmax = 0.501 +/- 0.08; Kd = 14.65 +/- 1.82 nM) or ethanol-induced motor incoordination. These results confirm an important role of the striatal adenosine A1 receptor in mediating certain motor-related physiological effects of ethanol.

Animals↗
PubMed1997

DNA antisense therapy for asthma in an animal model.

Asthma is an inflammatory disease characterized by bronchial hyper-responsiveness that can proceed to life-threatening airway obstruction. It is one of the most common diseases in industrialized countries, and in the United States accounts for about 1% of all healthcare costs. Asthma prevalence and mortality have increased dramatically over the past decade, and occupational asthma is predicted to be the pre-eminent occupational lung disease in the next decade. Increasing evidence suggests that adenosine, an endogenous purine that is involved in normal physiological processes, may be an important mediator of bronchial asthma. In contrast to normal individuals, asthmatic individuals respond to adenosine challenge with marked airway obstruction, and concentrations of adenosine are elevated in the bronchoalveolar lavage fluid of asthma patients. We performed a randomized crossover study using the dust mite-conditioned allergic rabbit model of human asthma. Administration of an aerosolized phosphorothioate antisense oligodeoxynucleotide targeting the adenosine A1 receptor desensitized the animals to subsequent challenge with either adenosine or dust-mite allergen.

Adenosine↗
PubMed1997

Induction of peroxisomal enzymes in rat liver by dehydroepiandrosterone sulfate.

Male F-344 rats, when treated with either 150 mg/kg or 300 mg/kg body weight of DHEAS for 14 days, produced a dose-dependent increase in liver weight and peroxisomal beta-oxidation activity, characteristic of peroxisomal proliferation. Contrary to previous observations in vitro, we also found a significant increase in catalase activity in rat liver with the higher dose of the steroid. Furthermore, the in vivo induction of peroxisomal beta-oxidation by DHEAS observed in our study was significantly less than reported in vitro, and also unlike previously reported in vitro results, was approximately equivalent to DHEA administered in vivo.

Animals↗
PubMed1997

Effects of ubiquinone and mevalonic acid on hepatic peroxisomal enzymes induced by dehydroepiandrosterone.

The adrenal steroid, dehydroepiandrosterone (DHEA) has been identified as a peroxisome proliferator. We examined the effects of the cellular antioxidant ubiquinone and its precursor mevalonic acid on the induction of enzymes associated with DHEA-mediated peroxisome proliferation in male F-344 rats. Upon treatment with DHEA (300 mg/kg orally for 14 days), there was a significant increase in hepatic activities of peroxisomal beta-oxidation (3 fold), 3-ketoacyl-CoA thiolase (4 fold) and catalase (1.8 fold). Co-administration of either mevalonic acid (100 mg/kg intraperitoneally) or ubiquinone (50 mg/kg orally) with DHEA significantly attenuated the DHEA-mediated induction of these enzymes. However, neither ubiquinone nor mevalonic acid alone significantly altered peroxisomal enzyme activities in rat liver. These data suggest that exogenous administration of ubiquinone or mevalonic acid can modulate the induction of the enzymes involved in peroxisome proliferation.

Acetyl-CoA C-Acyltransferase↗
PubMed1996

NPY-Y1 receptor antisense injected centrally in rats causes hyperthermia and feeding.

The central actions of neuropeptide Y antisense oligodeoxynucleotide (aNPY) and NPY-Y1 receptor antisense (aNPY-Y1) on body temperature (Tb), feeding and body weight of unrestrained rats were determined by the repeated intracerebroventricular (i.c.v.) injection of 0.5 microgram doses. aNPY-Y1 caused intense phasic rises in Tb, lowered body weight and caused transient feeding. aNPY increased food intake paradoxically, accompanied by a gain in body weight but did not affect Tb. Circadian activity was unaffected by either antisense oligodeoxynucleotide, and the mismatched NPY (mNPY) was without effect. These results show that NPY-Y1 receptors underlie the central thermolytic action of NPY, since aNPY-Y1 induces hyperthermic responses. Overall, the functional reduction in NPY activity by aNPY might cause a compensatory de novo synthesis of NPY in structures remote from the ventricles to augment feeding behavior.

Animals↗
PubMed1996

Antisense to NPY-Y1 demonstrates that Y1 receptors in the hypothalamus underlie NPY hypothermia and feeding in rats.

Neuropeptide Y (NPY) is a highly potent endogenous peptide which when injected into the medial hypothalamus causes spontaneous eating behaviour and an intense fall in body temperature (Tb). This study used antisense oligodeoxynucleotides (ODNs) to determine whether the Y1 subtype of NPY receptor could underlie these remarkable physiological responses. In the unrestrained rat, the ventromedial hypothalamus (VMH) which is highly reactive to NPY was injected with antisense for NPY (aNPY), Y1 receptors (aNPY-Y1) and mismatched controls (mNPY; mNPY-Y1). After cannulae were implanted bilaterally in the brain of 19 rats, 0.4 or 0.8 microgram per 0.8 microliter of the phosphorothioate synthesised ODNs were delivered to the VMH of the rats at 12 h intervals over 2 d. Only the lower dose of aNPY-Y1, but not aNPY, evoked an intense phasic rise in the Tb following each micro-injection. Simultaneously, 0.4 microgram per 0.8 microliter of aNPY-Y1, but not aNPY, suppressed feeding behaviour after a sequence of micro-injections and on the following day. Body weights and locomotor activity of the rats likewise declined concomitantly with the hyperthermia and hypophagia caused by the Y1 receptor antisense. Neither of the control ODNs for NPY or Y1 receptors injected similarly in the VMH of the rats exerted any effects on these measures. These results clearly provide convincing evidence that in the VMH the Y1 subtype of NPY receptor mediates, in part, the neuronal mechanisms responsible for spontaneous feeding and hypothermia produced by native NPY when applied directly to this structure. The concurrent decline in body weight and activity caused by aNPY-Y1 could be caused by the episodes of hyperthermia.

Animals↗
PubMed1995

Hypotensive effects of [D-Tyr27,36, D-Thr32]Neuropeptide Y (27-36).

An analogue of the 10 C-terminal amino acids of neuropeptide Y (NPY) containing three D-isomeric substitutions (27-36-D) has been synthesized and its cardiovascular activity studied in Sprague-Dawley (SD) and spontaneously hypertensive (SHR) rats. Intravenous administration of 1000 nmol/kg 27-36-D decreases MAP in SHR (-59.9 +/- 5.0 mmHg) and SD rats (-44.4 +/- 4.7 mmHg). The hypotension produced by 1000 nmol/kg 27-36-D diminished by 71.2% following pretreatment with the histamine receptor antagonist diphenhydramine, although histamine depletion with compound 48/80 does not significantly alter this hypotension. These data suggest that NPY (27-36)-D produces a profound and sustained hypotension in two strains of rat which is partially attributable to activity at histamine receptors.

Animals↗
PubMed1995

Anorexic action of a new potential neuropeptide Y antagonist [D-Tyr27,36, D-Thr32]-NPY (27-36) infused into the hypothalamus of the rat.

Neuropeptide Y (NPY) produces a vigorous feeding response in several species when it is injected into hypothalamic structures involved in eating behavior. The purpose of this study was to determine whether a unique carboxy terminal fragment of NPY would alter the pattern of eating induced in the rat either by NPY injected into the hypothalamus or by a 24-h period of food deprivation. In this case, two L-tyrosine residues and one L-threonine residue of the NPY27-36 fragment were transformed to their D-conformation to produce [D-Tyr27,36,D-Thr32]-NPY (27-36), i.e., D-NPY27-36. Guide cannulae for microinjection were implanted stereotaxically just dorsal to the paraventricular nucleus (PVN) or ventromedial hypothalamus (VMH) of 24 adult male Sprague-Dawley rats. Following postoperative recovery, a microinjection of artificial CSF or 1.1 microgram or 3.3 micrograms of a peptide was made directly into the PVN or VMH as follows: native NPY; D-NPY27-36; or [L-Tyr27,36, L-Thr32]-NPY (27-36), i.e., L-NPY27-36. Food intakes were measured at intervals of 0.25, 0.5, 1.1, 2.0, 4.0, and 24 h. When D-NPY27-36 was microinjected at NPY reactive sites in the PVN or VMH of the rat 15 min before a similar microinjection of NPY, the intense eating response induced by the peptide was reduced significantly. Not only was the effect dose dependent, but D-NPY27-36 also augmented the latency to feed. A mixture of the two doses of NPY and D-NPY27-36 injected at the same hypothalamic loci did not attenuate the intake of food but tended to enhance the feeding response in the rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Inhibition of protein farnesyltransferase: a possible mechanism of tumor prevention by dehydroepiandrosterone sulfate.

Dehydroepiandrosterone sulfate (DHEAS) is the most abundant adrenal steroid with apparent anticarcinogenic properties. Given our recent observation of the dehydro-epiandrosterone-mediated inhibition of protein isoprenylation and the fact that 99% of the circulating dehydro-epiandrosterone is sulfated, with less than 1% representing the free steroid, we investigated the effects of DHEAS on post-translational isoprenylation of proteins. We here report that exposure of HT-29 SF human colonic adenocarcinoma cells to DHEAS inhibited the incorporation of [3H]mevalonate into cellular proteins in a dose-dependent manner when endogenous mevalonate synthesis was blocked by lovastatin. Interestingly, significant inhibition was observed at concentrations of DHEAS which are comparable to peak serum levels of this steroid occurring in the second decade of life. Immunoprecipitation revealed that isoprenylation of p21ras was also suppressed in DHEAS-treated HT-29 SF cells. In a cell-free system, DHEAS inhibited the farnesylation of a biotinylated decapeptide corresponding to the C-terminus of K-ras by 50% at a concentration of 100 microM. This suggests that DHEAS inhibits isoprenylation of cellular proteins, including p21ras, at a point in the mevalonate pathway distal to 3-hydroxy-3-methylglutaryl-CoA reductase and that the DHEAS-mediated suppression of protein farnesylation may largely be due to inhibition at the level of protein farnesyltransferase. Thus, these findings may provide a plausible explanation for the antitumor activity of DHEAS.

Alkyl and Aryl Transferases↗
PubMed1993

Quantitation of 5-methylcytosine by one-dimensional high-performance thin-layer chromatography.

A method for the quantitative analysis of DNA 5-methylcytosine by one-dimensional high-performance thin-layer chromatography using alkylamino modified silica (HPTLC-NH2) plates is described. The preparative method is simple, involving enzymatic digestion of DNA with micrococcal nuclease and phosphodiesterase II to 3'-monophosphate nucleosides, conversion by T4 polynucleotide kinase to 32P-labeled 3',5'-bisphosphate nucleosides, and chromatographic separation of nuclease P1-cleaved 5'-monophosphate nucleosides. The weak, basic anion exchanger property of the HPTLC-NH2 plate enables separation of multiple samples in one dimension, whereas traditional polyethyleneimine cellulose plates require development of individual samples in two dimensions for analysis of 5'-methylcytosine.

5-Methylcytosine↗