Although cannabinoids are efficacious in laboratory animal models of inflammatory pain, their established cannabimimetic actions diminish enthusiasm for their therapeutic development. Conversely, fatty acid amide hydrolase (FAAH), the chief catabolic enzyme regulating the endogenous cannabinoid N-arachidonoylethanolamine (anandamide), has emerged as an attractive target for treating pain and other conditions. Here, we tested WIN 55212 and CB 1 mechanisms of action. However, the transient receptor potential vanilloid type 1 antagonist capsazepine did not affect either the antihyperalgesic or antiedematous effects of URB597. Finally, URB597 attenuated levels of the proinflammatory cytokines interleukin-1␤ and tumor necrosis factor ␣ in LPS-treated paws. These findings demonstrate that simultaneous elevations in non-neuronal and neuronal endocannabinoid signaling are possible through inhibition of a single enzymatic target, thereby offering a potentially powerful strategy for treating chronic inflammatory pain syndromes that operate at multiple levels of anatomical integration.Increased pain sensitivity is one of the most common and debilitating symptoms of inflammatory disorders and is caused by various mediators, including neuropeptides, eicosanoids, and cytokines (Dray and Bevan, 1993). Cannabis extracts and cannabinoid receptor agonists have long been known to elicit analgesic and anti-inflammatory actions (Sofia et al., 1973); however, the therapeutic utility of these drugs has been greatly limited by the occurrence of psychotropic side effects. The endogenous cannabinoid (endocannabinoid) system, consisting of naturally occurring ligands (e.g., anandamide) and 2-arachidonoyl glycerol (2-AG), enzymes regulating ligand biosynthesis and degradation, and two cloned cannabinoid receptors (i.e., CB 1 and CB 2 ) (Jhaveri et al., 2007;Ahn et al., 2008), provides multiple targets for the development of new pharmacological approaches for

The primary function of polymorphonuclear neutrophils (PMN) in the immune response appears to be acute phagocytic clearance of foreign pathogens and release of inflammatory mediators. Consistent with their assumed lack of major histocompatibility complex (MHC) class II expression, PMN have not been considered to play a role in antigen presentation and T-cell activation. However, recent reports have shown that human PMN can express MHC class II molecules both in vitro and in vivo after stimulation with either granulocyte-macrophage colony-stimulating factor (GM-CSF ) or interferon-γ (IFN-γ). Thus, under appropriate conditions, PMN could play a significant role in immune regulation, including T-cell activation. In this report, we demonstrate that human class II–expressing PMN can serve as accessory cells in superantigen (SAg)-mediated T-cell activation. This accessory activity for SAg presentation was present only after induction of MHC class II expression, and was especially pronounced following culture of PMN with GM-CSF plus IFN-γ, which acted synergistically to induce MHC class II molecules on PMN. Moreover, the level of MHC class II expression and the magnitude of SAg-induced T-cell responses were found to be highly correlated and distinctly donor dependent, with PMN from some donors repeatedly showing fivefold higher responses than PMN from other donors. On the other hand, culture of PMN with GM-CSF plus IFN-γ under conditions that resulted in optimal MHC class II expression did not enable them to function as antigen-presenting cells for either intact tetanus toxoid (TT) or for a TT peptide. These results delineate a new pathway for T-cell activation by SAg that may play an important role in the severity of SAg-induced inflammatory responses. They also identify a donor-specific polymorphism for induction of PMN MHC class II expression which may be of significance for therapies involving GM-CSF and IFN-γ.

In our effort to develop selective sphingosine kinase-2 (SphK2) inhibitors as pharmacological tools, a thiazolidine-2,4-dione analogue, 3-(2-amino-ethyl)-5-[3-(4-butoxyl-phenyl)-propylidene]-thiazolidine-2,4-dione (K145), was synthesized and biologically characterized. Biochemical assay results indicate that K145 is a selective SphK2 inhibitor. Molecular modeling studies also support this notion. In vitro studies using human leukemia U937 cells demonstrated that K145 accumulates in U937 cells, suppresses the S1P level, and inhibits SphK2. K145 also exhibited inhibitory effects on the growth of U937 cells as well as apoptotic effects in U937 cells, and that these effects may be through the inhibition of down-stream ERK and Akt signaling pathways. K145 also significantly inhibited the growth of U937 tumors in nude mice by both intraperitoneal and oral administration, thus demonstrating its in vivo efficacy as a potential lead anticancer agent. The antitumor activity of K145 was also confirmed in a syngeneic mouse model by implanting murine breast cancer JC cells in BALB/c mice. Collectively, these results strongly encourage further optimization of K145 as a novel lead compound for development of more potent and selective SphK2 inhibitors.

In our effort to develop multifunctional compounds that cotarget beta-amyloid oligomers (AbetaOs), cell membrane/lipid rafts (CM/LR), and oxidative stress, a series of bivalent multifunctional Abeta oligomerization inhibitors (BMAOIs) containing cholesterol and curcumin were designed, synthesized, and biologically characterized as potential treatments for Alzheimer's disease (AD). The in vitro assay results established that the length of spacer that links cholesterol and curcumin and the attaching position of the spacer on curcumin are important structural determinants for their biological activities. Among the BMAOIs tested, 14 with a 21-atom-spacer was identified to localize to the CM/LR of human neuroblastoma MC65 cells, to inhibit the formation of AbetaOs in MC65 cells, to protect cells from AbetaOs-induced cytotoxicity, and to retain antioxidant properties of curcumin. Furthermore, 14 was confirmed to have the potential to cross the blood-brain barrier (BBB) as demonstrated in a Caco-2 cell model. Collectively, these results strongly encourage further optimization of 14 as a new hit to develop more potent BMAOIs.

The isoflavone genistein (4,7,4'-trihydroxyisoflavone) is a phytoestrogen found in high levels in soy products that has been associated with decreased incidences of breast and prostate cancers. The potential effects of genistein on the immune system were evaluated in adult female B6C3F1 mice. Groups of mice were exposed to vehicle or genistein by gavage for 28 d. The doses of genistein used were 2, 6 and 20 mg/kg body. Consistent with the chemopreventive effect of genistein, exposure to this compound significantly increased host resistance to B16F10 tumor as reflected by a decrease in the number of lung tumor nodules after tumor cell injection at the middle and high dose levels. Inhibition of B16F10 tumor formation was not due to a direct effect of serum genistein and/or its metabolites on the proliferation of B16F10 tumor cells. When innate and acquired immune responses were evaluated, a dose-related increase of cytotoxic T-cell activity was observed in genistein-treated mice with significant changes observed at the middle and high dose levels. Furthermore, in vitro interleukin (IL)-2-stimulated natural killer (NK) cell activity was significantly enhanced in the high genistein dose group, although the basal NK cell activity was not affected. Although no affect on the mixed lymphocyte responses and anti-CD3 antibody-mediated splenocyte proliferation was observed, exposure to genistein significantly increased basal splenocyte proliferation. Exposure to genistein did not alter the activity of the mononuclear phagocyte system and the cytotoxic/cytostatic function of thioglycollate-recruited peritoneal cells on B16F10 tumor cells. Finally, exposure to genistein did not produce biologically meaningful changes in spleen immunoglobulin (Ig)M and IgG antibody-forming cell responses. In conclusion, genistein enhanced host resistance as evaluated in the B16F10 tumor model, which may be related to the increases in the activities of cytotoxic T cells and NK cells.

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Aflatoxin B1 (AFB1) is immunotoxic to animals and a suspected immunosuppressant in humans. In this study, we investigated the effects of AFB1 on splenic lymphocyte phenotypes and the inflammatory cytokine expression in male F344 rats. Exposure of animals to AFB1 (5-75 μg/kg body weight) for 1-week showed dose-dependent decreases in the percentage of splenic CD8+ T cells and CD3−CD8a+ NK cells. A general inhibition of the expression of IL-4 and IFN-γ by CD4+ T cells, IL-4 and IFN-γ by CD8a+ cells, and TNF-α expression by NK cells was also found; however, no concurrent histological changes in spleen tissue were present, suggesting acute immunosuppression without overt toxicity. Five-week exposure with AFB1 significantly increased the percentages of CD3+ and CD8+ T cells, especially at low doses (≤ 25 μg/kg). AFB1 treatment significantly decreased the anti-inflammatory cytokine IL-4 expression by CD4+ T cells and significantly increased the pro-inflammatory cytokine IFN-γ expression by CD4+ T cells and TNF-α expression by NK cells. These results indicated that repeated AFB1 exposure promotes inflammatory responses by regulating cytokine expression. Our data provides novel insights into the mechanisms by which AFB1 exposure differentially modulates the cell-mediated immune responses and suggests the involvement of an inflammatory response upon repeated exposure.

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