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The pro-inflammatory leukotrienes (LTs) are formed from arachidonic acid (AA) in activated leukocytes, where 5-lipoxygenase (5-LO) translocates to the nuclear envelope to assemble a functional complex with the integral nuclear membrane protein 5-LO-activating protein (FLAP). FLAP, a MAPEG family member, facilitates AA transfer to 5-LO for efficient conversion, and LT biosynthesis critically depends on FLAP. Here we show that the novel LT biosynthesis inhibitor BRP-187 prevents the 5-LO/FLAP interaction at the nuclear envelope of human leukocytes without blocking 5-LO nuclear redistribution. BRP-187 inhibited 5-LO product formation in human monocytes and polymorphonuclear leukocytes stimulated by lipopolysaccharide plus N-formyl-methionyl-leucyl-phenylalanine (IC 50 =7-10nM), and upon activation by ionophore A23187 (IC 50 =10-60nM). Excess of exogenous AA markedly impaired the potency of BRP-187. Direct 5-LO inhibition in cell-free assays was evident only at >35-fold higher concentrations, which was reversible and not improved under reducing conditions. BRP-187 prevented A23187-induced 5-LO/FLAP complex assembly in leukocytes but failed to block 5-LO nuclear translocation, features that were shared with the FLAP inhibitor MK886. Whereas AA release, cyclooxygenases and related LOs were unaffected, BRP-187 also potently inhibited microsomal prostaglandin E 2 synthase-1 (IC 50 =0.2μM), another MAPEG member. In vivo, BRP-187 (10mg/kg) exhibited significant effectiveness in zymosan-induced murine peritonitis, suppressing LT levels in peritoneal exudates as well as vascular permeability and neutrophil infiltration. Together, BRP-187 potently inhibits LT biosynthesis in vitro and in vivo, which seemingly is caused by preventing the 5-LO/FLAP complex assembly and warrants further preclinical evaluation., (Copyright © 2016 Elsevier Inc. All rights reserved.)

In this paper, we describe the synthesis and pharmacological evaluation of a series of 4-aminoquinolines. The compounds were characterised and tested in models of pain and inflammation, using the writhing test with acetic acid, formalin test, peritonitis test by zymosan and arthritis test with Freund's adjuvant complete assay. The results revealed that all of the 4-aminoquinolines that were prepared promoted anti-nociceptive activity as well as acute and chronic anti-inflammatory effects, with marked activity in the derivates labelled with BAQ and 7-CF3-MAQ. After 7 days of treatment, 7-CF3-MAQ did not induce significant hepatotoxicity, gastrotoxicity or nephrotoxicity., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

By generating prostaglandins, cyclooxygenase-2 (Cox-2/Ptgs2) plays a critical role in regulating inflammatory responses. While several inflammatory stimuli have been shown to increase Ptgs2 expression, less is known about how the transcription of this gene is terminated. Here we show that stimulation of macrophages with yeast zymosan, a TLR2/6 and dectin-1 agonist, causes a transient increase in the expression of Ptgs2 accompanied by a simultaneous increase in the expression of the transcriptional repressor, activating transcription factor-3 (Atf3). The expression of Ptgs2 was significantly higher in resident peritoneal macrophages isolated from Atf3(-/-) mice than that from Atf3(+/+) mice and was associated with higher prostaglandin production upon stimulation with zymosan. In activated macrophages, Atf3 accumulated in the nucleus and chromatin-immunoprecipitation analysis showed that Atf3 is recruited to the Ptgs2 promoter region. In acute peritonitis and in cutaneous wounds, there was increased leukocyte accumulation and higher levels of prostaglandins (PGE2/PGD2) in inflammatory exudates of Atf3(-/-) mice compared with WT mice. Collectively, these results demonstrate that during acute inflammation Atf3 negatively regulates Ptgs2 and therefore dysregulation of this axis could potentially contribute to aberrant Ptgs2 expression in chronic inflammatory diseases. Moreover, this axis could be a new therapeutic target for suppressing Ptgs2 expression and the resultant inflammatory responses., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Abnormal spontaneous activity of sensory neurons is observed in many different preclinical pain models, but its basis is not well understood. In this study mechanical and cold hypersensitivity were induced in rats after inflammation of the L5 dorsal root ganglion (DRG), initiated by local application of the immune stimulator zymosan in incomplete Freund's adjuvant. Mechanical hypersensitivity was evident by day 1 and maintained for 2 months. The model also showed reduction of rearing behavior in a novel environment. Microelectrode recordings made in isolated whole DRG on day 3 after inflammation showed a marked increase of spontaneous activity, predominantly with a bursting pattern. The incidence was especially high (44%) in Aαβ cells. Spontaneous activity and subthreshold membrane potential oscillations were completely blocked by tetrodotoxin (500 nM) and by riluzole (10 μM), a blocker of persistent sodium currents. In vivo, local perfusion of the inflamed DRG for the first 7 days with riluzole gave long-lasting, dose-dependent reduction in mechanical pain behaviors. Riluzole perfusion did not affect mechanical sensitivity in normal animals. Unmyelinated C cells had a very low incidence of spontaneous activity and were much less affected by riluzole in vitro. Taken together these results suggest that high-frequency and/or bursting spontaneous activity in Aαβ sensory neurons may play important roles in initiating pain behaviors resulting from inflammatory irritation of the DRG., (Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.)

Glutamine is the most abundant amino acid in the bloodstream. It is important in nucleotide synthesis, is anti-catabolic, has anti-oxidant properties via metabolism to glutathione, may enhance immune responsiveness and possesses immunoregulatory functions. Moreover, it reduces atrophy of intestinal mucosa in animals on total parenteral nutrition and prevents intestinal mucosal injury accompanying small bowel transplantation, chemotherapy and radiation. In the present study, we investigated the effects of glutamine on development of non-septic shock caused by zymosan. Mice received either zymosan (500 mg/kg, administered i.p., as a suspension in saline) or vehicle (saline). Glutamine (1.5 mg/kg i.p.) was administered 1 and 6h after zymosan administration. Organ failure and systemic inflammation in mice were assessed 18 h after administration of zymosan and/or glutamine. Glutamine-treatment reduced the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan-injection and also attenuated the pancreatic and gut injury. Inflammatory and apoptotic parameters were evaluated to better investigate the effects of the glutamine-administration. So, by immunohistochemical analysis and in vitro assays, we have clearly showed that glutamine reduces: 1) the histological damage in pancreas and gut; 2) the inducible nitric oxide synthase expression; 3) nitrotyrosine and poly (ADP-ribose) formation; 4) TNF-α and IL-1β tissue and plasma levels; 5) FasL localization; and 6) alteration of the balance between Bax and Bcl-2. In addition, at the end of the observation period (7 days), zymosan causes severe illness in the mice characterized by a systemic toxicity, significant loss of body weight and mortality. Glutamine-treatment significantly reduced all these parameters., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The immunomodulatory effect of juice obtained from leaves of Kalanchoe brasiliensis (Kb) on zymosan-induced inflammation was investigated. C57B110 mice received a subcutaneous injection of 150 microg zymosan in the footpad. After 7 days, there was an increase in footpad thickness from 176 +/- 4 to 236 +/- 9 x 10(-2) mm and in blood flow in the footpad area, monitored by 99mTc, from 98 +/- 4 to 694 +/- 59 counts per minute (cpm). Zymosan induced a severe infiltration of leukocytes into the articular tissues and a 13-fold increase in the adjacent popliteal lymph node (PLN) weight. Beginning 2 days after the injection, mice were treated daily for 5 days with different concentrations of lyophilised Kb juice dissolved in water. Treatment with 480 mg/kg/day reduced footpad thickness to 193 +/- 5 x 10(-2) mm, leukocyte infiltration and blood flow to 150 +/- 18 cpm in the footpad area. PLN weight in zymosan-injected mice decreased from 6.5 +/- 0.5 to 1.5 +/- 0.4 mg, similarly to the decrease after treatment with indomethacin (3 mg/kg/day). Flow cytometric analysis of lymph node cells showed an important reduction in B cell number in Kb-treated mice. Treatment over a period of 10 days was also effective at reducing zymosan-induced inflammation, even when started 7 days after injection. These data suggest anti-inflammatory and immunosuppressive effects of K. brasiliensis that may account for its popularity in folk medicine against rheumatic diseases.

Respiratory burst activity was induced in rat peritoneal macrophages by opsonized zymosan. Inhibitors were tested by administering them before or after the inducing agent: OX-42, an anti-rat macrophage complement receptor type 3 antibody, was active at an estimated concentration of 2.1 nM, and was more than 100-fold more potent when administered before, rather than after, opsonized zymosan. Indomethacin and dapsone, two agents with antiinflammatory activity, were also more effective before opsonized zymosan, but only in the 10(-3) to 10(-4) molar range. Inhibitors of eicosanoid synthesis, as well as the antiinflammatory prostaglandin E2, also reduced the respiratory burst.