Search

Abstract Nimesulide is a relatively selective cyclooxygenase (COX)-2 inhibitor, non-steroidal anti-inflammatory drug; it has been discovered in 1971 and firstly commercialized in Italy in 1985. There is much evidence that the pharmacological profile of nimesulide is peculiar and not shared with the other COX-2 selective inhibitors, suggesting that other molecular mechanisms besides inhibition of COX-2 derived prostaglandins are involved. Similarly, experimental data suggest that the gastrointestinal safety of nimesulide cannot be ascribed only to a COX-1 sparing effect. On the inflammatory process, the efficacy of nimesulide is dependent upon a wide spectrum of actions, due to the combination of effects on immune and non–immune cells. Early data demonstrated a central role for cyclic AMP (cAMP) in the anti-inflammatory effect of nimesulide; more recently, we have shown the involvement of the pathway ecto-5′-nucleotidase/adenosine A 2A receptor. To date, the molecular mechanism(s) that confers uniqueness to nimesulide have not yet been defined. To go inside the mechanism of action of an existing drug, such as nimesulide, would be helpful to refine its therapeutic use but also to identify new targets for novel therapeutic anti-inflammatory approach. Here, we focus on accumulated evidence for a peculiar pharmacological profile of nimesulide. [ABSTRACT FROM AUTHOR]

Abstract: Adenosine participates to asthma physiopathology by signaling through more than just one receptor subtype. Defining the role of each receptor is complicated by evidence that often results obtained on rodents do not coincide with human studies, but what emerges is that an important condition to establish hyperresponsiveness to adenosine in any species of sensitized animals is the exposure to allergen; this feature appears to be very similar to the human situation, since allergic humans regularly undergo exposure to allergen. Furthermore, A2B in humans, but A3 receptor in rodents, would mediate, indirectly, the bronchoconstriction in response to adenosine and would play the main role in adenosine-induced airway inflammation and airway hyperreactivity. On the other hand, A1 receptor over-expressed on asthmatic airways would mediate a direct adenosine bronchoconstrictor effect. Antagonists and agonists to adenosine receptors have been considered as antiasthmatic drugs but often their development has been limited by unwanted effects. Preventing adenosine accumulation in airways should be considered as a novel promising antiasthmatic strategy. [Copyright &y& Elsevier]

Abstract: The heat shock response is a highly conserved mechanism of protection elicited in the cell by various kinds of stimuli, such as heat, sodium arsenite, oxidants and inflammation. Among the mechanisms potentially involved in mediating the protective effects of hsp, one of the most investigated is the inhibition of pro-inflammatory gene expression such as inducible nitric oxide synthase (iNOS) and inflammatory cytokines. Nevertheless, data about the effects of heat shock response on cyclooxygenase-2 expression in activated macrophages are so far not available in literature. The aim of this study was to investigate the changes in cyclooxygenase-2 expression following lipopolysaccharide stimulation of heat shocked J774 murine macrophages. We found, by Western blotting analysis and reverse transcription–polymerase chain reaction analysis (RT-PCR), that the lipopolysaccharide-induced cyclooxygenase-2 gene expression was reduced in heat shocked cells. Such a reduction was associated to activation of heat shock factor, increased levels of heat shock protein 72 and inhibition of lipopolysaccharide-induced nuclear factor-κB binding activity. These data suggest that the heat shock response inhibits cyclooxygenase-2 gene expression at transcriptional level, i.e. by preventing the activation of nuclear factor-κB, and provide additional information about mechanism(s) underlying the anti-inflammatory effect of the heat shock proteins. [Copyright &y& Elsevier]

Abstract: Two new diterpenes, named paralianone (2) and pepluene (3), based, respectively, on rare paraliane and pepluane skeletons, have been isolated from Euphorbia paralias, together with two known analogues (4 and 5), and their stereostructure determined by spectroscopic methods. The isolated compounds were tested as anti-inflammatory agents in vitro for evaluating their ability to inhibit the nitric oxide production in LPS-stimulated J774 murine macrophages. Compound 4 showed the highest anti-inflammatory activity comparable to those recently discovered for pepluanone (1). The data obtained provided first insights towards the structure–activity relationship of this class of compounds highlighting the key role of D-ring structure. [Copyright &y& Elsevier]

Lipid mediators (LM) encompass pro-inflammatory prostaglandins (PG) and leukotrienes (LT) but also specialized pro-resolving mediators (SPM) which display pivotal bioactivities in health and disease. Pharmacological intervention with inflammatory disorders such as osteoarthritis and rheumatoid arthritis commonly employs anti-inflammatory drugs that can suppress PG and LT formation, which however, possess limited effectiveness and side effects. Here, we report on the discovery and characterization of the two novel benzoxanthene lignans 1 and 2 that modulate select LM biosynthetic enzymes enabling the switch from pro-inflammatory LT to SPM biosynthesis as potential pharmacological strategy to intervene with inflammation. In cell-free assays, compound 1 and 2 inhibit microsomal prostaglandin E 2 synthase-1 and leukotriene C 4 synthase (IC 50 ∼ 0.6–3.4 µM) and potently interfere with 5-lipoxygenase (5-LOX), the key enzyme in LT biosynthesis (IC 50 = 0.04 and 0.09 µM). In human neutrophils, monocytes and M1 and M2 macrophages, compound 1 and 2 efficiently suppress LT biosynthesis (IC 50 < 1 µM), accompanied by elevation of 15-LOX-derived LM including SPM. In zymosan-induced murine peritonitis, compound 1 and 2 ameliorated self-limited inflammation along with suppression of early LT formation and elevation of subsequent SPM biosynthesis in vivo. Together, these novel benzoxanthene lignans promote the LM class switch from pro-inflammatory towards pro-resolving LM to terminate inflammation, suggesting their suitability as novel leads for pharmacotherapy of arthritis and related inflammatory disorders. [ABSTRACT FROM AUTHOR]

Extracellular adenosine formation from ATP is controlled by ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase/CD39) and ecto-5′-nucleotidase (e-5NT/CD73); the latter converts AMP to adenosine and inorganic phosphate, representing the rate limiting step controlling the ratio between extracellular ATP and adenosine. Evidence that cellular expression and activity of CD39 and CD73 may be subject to changes under pathophysiological conditions has identified this pathway as an endogenous modulator in several diseases and was shown to be involved in the molecular mechanism of drugs, such as methotrexate, salicylates , interferon-β. We evaluated whether CD73/adenosine/A 2A signalling pathway is involved in nimesulide anti-inflammatory effect, in vivo and in vitro. We found that the adenosine A 2A agonist, 4-[2-[[6-amino-9-( N -ethyl-β- d -ribofuranuronamidosyl)-9H-purin-2-yl]amino]ethyl]benzenepropanoic acid hydrochloride (CGS21680, 2 mg/kg ip.), inhibited carrageenan-induced rat paw oedema and the effect was reversed by co-administration of the A2A antagonist -(2-[7-amino-2-[2-furyl][1,2,4]triazolo[2,3- a ][1,3,5]triazin-5-yl-amino]ethyl)phenol (ZM241385; 3 mg/kg i.p.). Nimesulide (5 mg/kg i.p.) anti-inflammatory effect was inhibited by pre-treatment with ZM241385 (3 mg/kg i.p.) and by local administration of the CD73 inhibitor, adenosine 5′-(α,β-methylene)diphosphate (APCP; 400 μg/paw). Furthermore, we found increased activity of 5′-nucleotidase/CD73 in paws and plasma of nimesulide treated rats, 4 h following oedema induction. In vitro, the inhibitory effect of nimesulide on nitrite and prostaglandin E 2 production by lipopolysaccharide-activated J774 cell line was reversed by ZM241385 and APCP. Furthermore, nimesulide increased CD73 activity in J774 macrophages while it did not inhibit nitrite accumulation by lipopolysaccharide-activated SiRNA CD73 silenced J774 macrophages. Our data demonstrate that the anti-inflammatory effect of nimesulide in part is mediated by CD73-derived adenosine acting on A 2A receptors. [ABSTRACT FROM AUTHOR]

The NF-κB transcriptional response is tightly regulated by a number of processes including the phosphorylation, ubiquitination, and subsequent proteasomal degradation of NF-κB subunits. The IκB family protein BCL-3 stabilizes a NF-κB p50 homodimer•DNA complex through inhibition of p50 ubiquitination. This complex inhibits the binding of the transcriptionally active NF-κB subunits p65 and c-Rel on the promoters of NF-κB target genes and functions to suppress inflammatory gene expression. We have previously shown that the direct interaction between p50 and BCL-3 is required for BCL-3-mediated inhibition of pro-inflammatory gene expression. In this study we have used immobilized peptide array technology to define regions of BCl-3 that mediate interaction with p50 homodimers. Our data show that BCL-3 makes extensive contacts with p50 homodimers and in particular with ankyrin repeats (ANK) 1, 6, and 7, and the N-terminal region of Bcl-3. Using these data we have designed a BCL-3 mimetic peptide based on a region of the ANK1 of BCL-3 that interacts with p50 and shares low sequence similarity with other IκB proteins. When fused to a cargo carrying peptide sequence this BCL-3-derived peptide, but not a mutated peptide, inhibited Toll-like receptor-induced cytokine expression in vitro. The BCL-3 mimetic peptide was also effective in preventing inflammation in vivo in the carrageenan-induced paw edema mouse model. This study demonstrates that therapeutic strategies aimed at mimicking the functional activity of BCL-3 may be effective in the treatment of inflammatory disease. [ABSTRACT FROM AUTHOR]

Abstract: Airway hyperreactivity is characterized by increased responsiveness to bronchoconstrictor stimuli and it is hallmark of asthma. Adenosine is an ubiquitous signaling nucleoside resulting from ATP catabolism, whose extracellular levels increase following cellular damage or stress. Adenosine plays a role in asthma; asthmatics, but not normal subjects, present bronchoconstriction following inhalation of adenosine or of its precursor, adenosine-5′-monophosphate, most likely via adenosine A2B receptor on mast cells. However, the mechanism underling the increased airway smooth muscle sensitivity to adenosine in asthmatics remains to be elucidated. Early experimental studies suggested the involvement of A1 receptor; this hypothesis has been confirmed by more recent studies on guinea pigs and is corroborated by the finding of an increased adenosine A1 expression on asthmatic bronchial tissues. Brown Norway rats, the strain usually used to assess asthma models, develop hyperresponsiveness to adenosine 3h following allergen challenge, but not 24h thereafter, without involvement of A1 receptor. Here, we investigated the role of adenosine A1 receptor in sensitized Wistar rats showing airway hyperresponsiveness 24h following allergen challenge. We found that on bronchi of sensitized Wistar rats challenged with allergen there is an increased adenosine A1 receptor expression on smooth muscle that is responsible for hyperresponsiveness to adenosine and ovalbumin. [Copyright &y& Elsevier]

Abstract: Monocyte chemotactic protein-3 (MCP-3), also known as CCL7, belongs to the monocyte chemotactic protein (MCP) subfamily of the CC chemokines that includes MCP-1/CCL2, MCP-2/CCL8, MCP-4/CCL13, and MCP-5/CCL12. Few studies have examined the role of MCP-3 in vascular pathologies such as atherosclerosis and restenosis in which smooth muscle cell (SMC) proliferation plays an important role. In this study, we investigated the effect of MCP-3 on human coronary artery smooth muscle cell (CASMC) proliferation. MCP-3 induced concentration-dependent CASMC proliferation with the maximum stimulatory effect at 0.3ng/mL (about 50% vs unstimulated cells) assessed by bromodeoxyuridine (BrdU) uptake and direct cell counting. Anti-MCP-3 antibody (20ng/mL) completely inhibited cell proliferation, demonstrating the specificity of the proliferative effect of MCP-3. Moreover, the MCP-3-induced CASMC proliferation was blocked by RS 102895 (0.06–6μM), a specific antagonist of chemokine receptor 2 (CCR2). The mitogenic effect of MCP-3 appeared to be dependent on ERK1/2 MAPK and PI3K signaling pathway activation, as demonstrated by the reduction of MCP-3-induced CASMC proliferation observed after the treatment of cells with U0126 (1μM) and LY-294002 (5μM), selective inhibitors of ERK 1/2 and PI3K activation, respectively. We found no relationship between MCP-3-induced CASMC proliferation and nuclear factor-κB activation. Moreover, we found that tumor necrosis factor-α (TNF-α, 30ng/mL) and interleukin-1β (IL-1β, 1ng/mL) both induced time-dependent increase of MCP-3 production by CASMCs, which was reduced by the anti-MCP-3 antibody (20ng/mL), suggesting that the mitogenic effect of these stimuli is due, at least in part, to MCP-3. In conclusion, our results demonstrate that MCP-3 is produced by human CASMCs and directly induces CASMC proliferation in vitro, suggesting a potential role for this chemokine in vascular pathology. [Copyright &y& Elsevier]

Abstract: Melanoma is the most aggressive form of skin cancer, it originates from melanocytes and its incidence has increased in the last decade. Recent advances in the understanding of the underlying biology of the progression of melanoma have identified key signalling pathways that are important in promoting melanoma tumourigenesis, thus providing dynamic targets for therapy. One such important target identified in melanoma tumour progression is the Nuclear Factor-κB (NF-κB) pathway. In vitro studies have shown that NF-κB binding is constitutively elevated in human melanoma cultures compared to normal melanocytes. It has been found that a short cell-permeable peptide spanning the IKK-β NBD, named NBD peptide, disrupted the association of NEMO with IKKs in vitro and blocked TNFα-induced NF-κB activation in vivo. In the present study we investigated the effect of the NBD peptide on NF-κB activity and survival of A375 human melanoma cells. We found that NBD peptide is able to inhibit the proliferation of A375 cells, which present constitutively elevated NF-κB levels. Inhibition of cell proliferation by NBD peptide was associated with direct inhibition of constitutive NF-κB DNA-binding activity and induction of apoptosis by activation of caspase-3 as confirmed by the cleavage and consequently inactivation of poly (ADP ribose) polymerase (PARP-1) known as the best marker of this process. [Copyright &y& Elsevier]