IL-1beta-induced monocyte chemoattractant protein-1 gene expression in endothelial cells is blocked by proteasome inhibitors

Human monocyte chemoattractant protein-1 (MCP-1) is expressed by a variety of cell types in response to various stimuli. MCP-1 expressed by the endothelium plays an important role in cell migration and activation. MCP-1 is a major chemoattractant for monocytes, T lymphocytes, and basophils. In the present study, we present evidence that the proteasome complex is involved in mediating the interleukin (IL)-1beta induction of MCP-1 in endothelial cells. We present evidence that a proteasome inhibitor, N-acetyl-leucinyl-leucinyl-norleucinal (norLeu), and the protease inhibitor tosyl-Phe-chloromethylketone (TPCK) block IL-1beta induction of MCP-1 protein expression. norLeu and TPCK also blocked IL-1beta-induced MCP-1 promoter-driven reporter gene expression as well as nuclear factor (NF)-kappaB-mediated reporter gene expression. The effects of norLeu were due to its inhibition of the proteasome rather than calpain, because other calpain inhibitors had no effect on MCP-1 expression. In contrast to TPCK, which blocked NF-kappaB translocation to the nucleus, norLeu had no effect on NF-kappaB nuclear translocation or IL-1beta-induced phosphorylation of p65. This study demonstrates that the proteasome pathway is involved in IL-1beta-induced MCP-1 gene expression in human endothelial cells.     

Condensed heterocyclic compounds: synthesis and antiinflammatory activity of novel thiazolo[3,2-alpha] pyrimidines

In this study, thirty six new 2-benzylidene-7-methyl-3-oxo-5- phenyl-2,3-dihydro-5H-thiazolo[3,2-alpha]pyrimidine-6-carboxylic acid methyl esters were synthesized and characterized by spectral, crystallographic, and elemental analysis. The antiinflammatory activity of the compounds was tested by the carrageenan hind paw edema test. It was found that compound 6a having a 2-meth-oxyphenyl group at position 5 and a benzylidene group at position 2 was the most potent compound in this series. All the compounds that were tested for ulcer activity gave positive results.     

Suppression of granulopoiesis by vesnarinone

The diverse intrarenal effects of the prostaglandins (PG) are mediated by distinct guanine nucleotide regulatory protein (G-protein)-coupled receptors. The cDNA for these receptors have been cloned, their signal transduction mechanisms determined, and their intrarenal distribution mapped. PGE2, the major intrarenal prostaglandin, interacts with at least three distinct E-prostanoid (EP) receptors that are highly expressed in specific regions of the kidney. Each EP receptor not only selectively binds PGE2, but also preferentially couples to different signal transduction pathways, including: stimulation of cAMP generation, via Gq (EP2 and EP4 receptors); inhibition of cAMP generation, via Gi (EP3 receptors); and activation of phosphatidylinositol hydrolysis (EP1 receptor), via one of the Gq family members. Activation of each these EP receptors is responsible for a distinct renal effect of PGE2, including its well-described renal hemodynamic and transport effects along the nephron. Other intrarenal prostanoid receptors include the PGF2 alpha receptor (FP), the thromboxane A2 receptor (TP) and the prostacyclin receptor (IP). Knowledge about localization of these receptors and their affinities for receptor-selective agonists and antagonists should aid in the understanding of renal disease and the development of therapeutic strategies for the use of these prostaglandin analogs in select renal diseases.     

A new antiinflammatory compound, leumedin, inhibits modification of low density lipoprotein and the resulting monocyte transmigration into the subendothelial space of cocultures of human aortic wall cells

Addition of leumedin, N-[9H-(2,7-dimethylfluorenyl-9-methoxy) carbon]-L-leucine at 30-60 microM together with LDL almost completely prevented the induction of monocyte chemotactic protein mRNA, reduced monocyte chemotactic protein 1 levels by 84%, and inhibited monocyte migration into the subendothelial space of cocultures of human aortic wall cells by < or = 98%. LDL incubated with leumedin formed a stable complex that remained intact even after refloating in an ultracentrifuge. Leumedin at 50 microM did not change conjugated diene formation during coculture modification of LDL or Cu++ catalyzed oxidation of LDL. Unlike LDL from control rabbits, LDL isolated from rabbits that were injected with 20 mg/kg leumedin was remarkably resistant to modification by the coculture and did not induce monocyte migration to a significant degree. Moreover, HDL isolated from rabbits injected with leumedin was far more effective in protecting against LDL modification by the artery wall cocultures than HDL from control rabbits. We conclude that leumedins can associate with lipoproteins in vivo, rendering LDL resistant to biological modification and markedly amplifying the protective capacity of HDL against in vitro LDL oxidation by artery wall cells.     

Evidence for delayed neurotoxicity produced by methylmercury

Delayed toxicity as a result of developmental methylmercury exposure was identified in mice two decades ago by Spyker, who observed kyphosis, neuromuscular deficits, and other severe abnormalities as the mice aged. Delayed neurotoxicity was also observed in monkeys treated with methylmercury from birth to seven years of age. When these monkeys reached 13 years of age, individuals began exhibiting clumsiness not present previously. Further exploration revealed that treated monkeys required more time to retrieve treats than did nonexposed monkeys and displayed abnormalities on a clinical assessment of sense of touch in hands and feet, despite the fact that clinical examinations performed routinely during the period of dosing had not yielded abnormal results. Another group of monkeys, dosed from in utero to four years of age, also took longer to retrieve treats when assessed years after cessation of exposure. These observations were pursued in both groups of monkeys by objective assessment of somatosensory function in the hands: both groups of monkeys exhibited impaired vibration sensitivity. These results are strongly suggestive of a delayed neurotoxicity manifested when these monkeys reached middle age. Data from persons with Minamata disease also provide evidence for delayed neurotoxicity. Perhaps the strongest piece of evidence comes from a study of over 1100 Minamata patients over 40 years old, in which difficulty in performing daily activities increased as a function of age compared to matched controls. Methylmercury may represent the only environmental toxicant for which there is good evidence for delayed neurotoxicity that may be manifested many years after cessation of exposure.     

Modulation of human monocyte functions by Fc fragments of IgG: a comparison to other monocyte 'activators'

Human monocytes were maintained in tissue culture and the effect of various stimuli on their morphology and capacity to synthesize and secrete total protein, lysozyme, acid phosphatase, prostaglandin E and the second component of complement were determined. Human monomeric IgG, Fab fragments and albumin had no effect on the secretion of these products. However, addition of Fc fragments significantly decreased the synthesis of both lysosomal enzymes and the second component of complement and increased production of prostaglandin E. The addition of Con A to the monocyte monolayers resulted in a similar response. Latex particles slightly increased the secretion of acid phosphatase and C2, but had no effect on lysozyme secretion. Fc fragments also stimulated protein synthesis by monocyte monolayers cultured in serum-free medium. These 'activators' and endotoxin- or antigen-activated mononuclear cell supernatants (AMNS) resulted in varying degrees of increased spreading and adherence of the monocytes. The results of these studies suggest that the molecular species inducing the 'activated state' qualitatively and quantitatively determines the characteristics of the secretory response.     

A review of nonpesticide phosphate ester-induced neurotoxicity in cattle

Nonpesticide phosphate esters induce delayed neurotoxicity in cattle. The most common exposures are to complex mixtures of triaryl phosphate used in lubricating oils. Oral ingestion is most common, but dermal exposures have also occurred. Clinical signs of cholinesterase (ChE) inhibition may or may not be seen. Depending on the biochemical targets, the percent reduction in blood ChE is variable and can be < 30% of normal activity. Organophosphate ester-induced delayed neurotoxicity cannot be predicted by inhibition of blood ChEs. Signs of delayed neurotoxicity occur 2 to 25 d after exposure; these signs are neurologic deficiencies of the antigravity muscles and the muscles of the urinary bladder and larynx. Affected cattle may dribble urine and some may be mute. Signs of ChE inhibition generally are not observed in animals with neurological deficiencies. Pathologic findigs are axonopathy and myelin degeneration of nerves with long axons located in both the peripheral and central nervous systems. In the spinal cord, location of the affected nerve tracts is variable. Degenerative changes occur in motor neurons. Calves are less susceptible to organophosphate ester-induced delayed neurotoxicity than cows. A dose of 500 mg triaryl phosphate/kg body weight will produce complete paralysis in a mature cow in 26 d.     

Alleviation of monocrotaline-induced pulmonary hypertension by antibodies to monocyte chemotactic and activating factor/monocyte chemoattractant protein-1

Administration of monocrotaline (MCT) causes pulmonary vascular lesions consisting of monocyte/macrophage infiltration in the early phase and medial thickening in pulmonary arteries and arterioles associated with pulmonary hypertension (PH) in the later phase. However, the molecular mechanism of monocyte/macrophage infiltration and its roles remain elusive. Herein, we have evaluated the role of a potent monocyte chemotactic and activating chemokine/monocyte chemoattractant protein-1 (MCAF/MCP-1) in MCT-induced PH in rats. A single injection of MCT induced PH at Day 21, as evidenced by increases in the ratio of right ventricular to left ventricular and septum weights (RV/LV+S) and right ventricular systolic pressure (RVSP). A significant increase in macrophage number in lungs started at Day 14, reaching a maximum at Day 21. MCAF/MCP-1 levels in bronchoalveolar lavage fluids were elevated significantly at Day 14 and remained high until Day 28, whereas plasma MCAF/MCP-1 levels increased at Day 7, returning to normal levels by Day 21. Immunoreactive MCAF/MCP-1 proteins were mainly detected in macrophages in alveoli and in perivascular regions of pulmonary arterioles and venules. Intravenous administration of anti-MCAF/MCP-1 antibodies with MCT significantly decreased macrophage infiltration and eventually reduced the increases in RV/LV+S and RVSP, as well as medial thickening of pulmonary arterioles. Thus, MCAF/MCP-1 is essentially involved in MCT-induced PH by recruiting and activating macrophages.     

Neurological monitoring of neurotoxicity induced by paclitaxel/cisplatin chemotherapy

Thiazolidinediones are potent antidiabetic compounds, in both animal and human models, which act by enhancing peripheral sensitivity to insulin. Thiazolidinediones are high-affinity ligands for peroxisome proliferator-activated receptor-gamma, a key factor for adipocyte differentiation, and they are efficient promoters of adipocyte differentiation in vitro. Thus, it could be questioned whether a thiazolidinedione therapy aimed at improving insulin sensitivity would promote the recruitment of new adipocytes in vivo. To address this problem, we have studied the in vivo effect of pioglitazone on glucose metabolism and gene expression in the adipose tissue of an animal model of obesity with insulin resistance, the obese Zucker (fa/fa) rat. Pioglitazone markedly improves insulin action in the obese Zucker (fa/fa) rat, but doubles its weight gain after 4 weeks of treatment. The drug induces a large increase of glucose utilization in adipose tissue, where it stimulates the expression of genes involved in lipid metabolism such as the insulin-responsive GLUT, fatty acid synthase, and phosphoenolpyruvate carboxykinase genes, but decreases the expression of the ob gene. These changes are related to both an enhanced adipocyte differentiation, as shown by the large increase in the number of small adipocytes in the retroperitoneal fat pad, and a direct effect of pioglitazone on specific gene expression (phosphoenolpyruvate carboxykinase and ob genes) in mature adipocytes.     

Suppression of male-specific cytochrome P450 isoforms by bisphenol A in rat liver

IBD results from the interaction of genetic and environmental factors (e.g., smoking). Clinical suspicion is the key to diagnosis, which then rests on colonoscopy, histopathological examination of multiple biopsy specimens, small bowel barium radiology and faecal examination. The primary goal of treatment is remission--histological in ulcerative colitis and symptomatic in Crohn's disease. Treating active disease and maintaining remission require different approaches. For active disease, short term corticosteroids are the mainstay of treatment, while immunosuppressive drugs are important in chronically active disease. For maintenance, mesalazine-delivering drugs and immunosuppressive agents are efficacious in both ulcerative colitis and Crohn's disease; patients with Crohn's disease should not smoke.     

Synthesis and antiplatelet, antiinflammatory, and antiallergic activities of substituted 3-chloro-5,8-dimethoxy-1,4-naphthoquinone and related compounds

2-Amino (6), 2-alkylamino (7-8), 2-methoxy (9), 2-acetamido (10), and 5,8-diacetoxy (11) derivatives of the lead compound 2,3-dichloro-5,8-dimethoxy-1,4-naphthoquinone (4) were synthesized, together with 6,7-dichloro-5,8dimethoxy-1,4-naphthoquinone (5), a positional isomer of 4. Antiplatelet, antiinflammatory, and antiallergic activities were evaluated, and most compounds were quite potent in all assays. Compounds 5 and 9-11 were especially active; however, 5 was ineffective against neutrophil superoxide formation, and 10 was ineffective against mast cell degranulation.     

N-methyl-D-aspartate neurotoxicity in hippocampal slices: protection by aniracetam

Aniracetam, a drug known to elicit cognition enhancing properties in both animals and humans, was found to counteract the neurotoxicity induced by excitatory amino acids in primary cultures of cerebellar neurons. We report here that aniracetam prevents the neurotoxic effect induced by N-methyl-D-aspartate (NMDA) in rat hippocampal slices. Time-course experiments showed that the aniracetam-induced neuroprotection does not require preincubation of the slices with the drug. Maximal effective concentration of aniracetam was 10 microM. Since the NMDA-mediated cell death in hippocampal slices is considered a valuable experimental model of ischemia, these results suggest a possible novel therapeutic application for aniracetam.     

Suppression of ventricular ectopic depolarizations by tocainide

In a previous clinical study we demonstrated that tocainide is effective in the suppression of ventricular ectopic depolarizations (VEDs) after single oral doses. This information provided the basis for evaluating this drug's antiarrhythmic efficacy after multiple dose administration according to a loading-maintenance regimen. Twelve patients with stable VEDs were given loading doses of tocainide (400-600 mg) with maintenance doses every 12 hours. Every 48 hours the dose was increased until either arrhythmia suppression to less than 25% of VED frequency during placebo administration or side effects occurred. Computer analysis of 12-hr telemetric ECGs taken 24-36 hr after each dosage increment documented effective suppression (76-95%) in 8 of 12 patients. Those subjects demonstrating suppression were randomly assigned to a cross-over study of placebo or active drug at the dosage found effective in the dose-ranging phase. Dosages for the cross-over stage ranged from 400 to 1100 mg every 12 hours. Comparison of the two five-day periods documented suppression in these patients (mean +/- SE = 83.3 +/- 4%). No serious side effects or undue drug accumulation occurred during the study. The data indicate that tocainide can effectively suppress VEDs for 8-12 hours in many patients and that continuous suppression could be possible on an 8-12 hr dosage regimen.     

Neuroprotection by nitric oxide against hydroxyl radical-induced nigral neurotoxicity

We investigated the effects of nitric oxide on an in vitro and in vivo generation of hydroxyl radicals, and in vivo neurotoxicity caused by intranigral infusion of ferrous citrate in rats. The formation of hydroxyl radicals in vitro, without exogenous hydrogen peroxide, was dose-dependent. Some nitric oxide donors (e.g. sodium nitroprusside) stimulated, while others (nitroglycerin, diethylamine/nitric oxide, nitric oxide in Ringer's solution) suppressed hydroxyl radical generation in vitro. A significant increase in extra-cellular hydroxyl radicals was detected in a brain microdialysis study. Intranigral infusion of ferrous citrate caused long-lasting lipid peroxidation and dopamine depletion in the ipsilateral nigral region and striatum, respectively. Sub-acute dopamine depletion in the striatum was positively correlated with acute lipid peroxidation in substantia nigra. Intranigral administration of nitric oxide did not affect striatal dopamine. Interestingly, nitric oxide in Ringer's protected nigral neurones against the oxidative injury. The results demonstrate that a regional increase in the levels of iron can result in hydroxyl radical generation and lipid peroxidation leading to neurotoxicity. It also demonstrates that exogenous nitric oxide can act as hydroxyl radical scavenger and protect neurones from oxidative injury.     

Inhibition of peripheral interleukin-1 beta-induced hyperalgesia by the intracerebroventricular administration of diclofenac and alpha-melanocyte-stimulating hormone

The present study was undertaken to investigate whether or not the endogeneous mechanisms in the brain can modulate the changes in nociception produced by peripherally-administered interleukin-1 beta (IL-1 beta) in rats. We administered diclofenac and alpha-melanocyte-stimulating hormone (alpha-MSH) into the lateral cerebroventricle (LCV) 10 min before the intraperitoneal (i.p.) injection of recombinant human IL-1 beta (rhIL-1 beta, 1 ng/kg-100 ng/kg) and then observed the changes in nociception using a hot-plate test. The i.p. injection of rhIL-1 beta (10 ng/kg and 100 ng/kg) reduced the paw-withdrawal latency without affecting the colonic temperature. The maximal reduction in the paw-withdrawal latency was observed 30 min after the i.p. injection of rhIL-1 beta at 100 ng/kg. The rhIL-1 beta (100 ng/kg)-induced hyperalgesia was inhibited by the LCV injection of both diclofenac (1 ng) and alpha-MSH (100 ng). The LCV injection of either diclofenac (1 ng) or alpha-MSH (100 ng) was found to have no effect on nociception by itself. These findings therefore suggest that the hyperalgesia induced by peripheral IL-1 beta can be modulated by a cyclooxygenase pathway of the arachidonate and alpha-MSH in the brain.