Resolvins of the D series are generated from docosahexaenoic acid, which are enriched in fish oils and are believed to exert beneficial roles on diverse inflammatory disorders, including inflammatory bowel disease (IBD). In this study, we investigated the anti-inflammatory effects of the aspirin-triggered resolvin D1 (AT-RvD1), its precursor (17(R)-hydroxy docosahexaenoic acid [17R-HDHA]) and resolvin D2 (RvD2) in dextran sulfate sodium (DSS)- or 2,4,6-trinitrobenzene sulfonic acid-induced colitis. Our results showed that the systemic treatment with AT-RvD1, RvD2, or 17R-HDHA in a nanogram range greatly improved disease activity index, body weight loss, colonic damage, and polymorphonuclear infiltration in both colitis experimental models. Moreover, these treatments reduced colonic cytokine levels for TNF-α, IL-1β, MIP-2, and CXCL1/KC, as well as mRNA expression of NF-κB and the adhesion molecules VCAM-1, ICAM-1, and LFA-1. Furthermore, AT-RvD1, but not RvD2 or 17R-HDHA, depended on lipoxin A4 receptor (ALX) activation to inhibit IL-6, MCP-1, IFN-γ, and TNF-α levels in bone marrow-derived macrophages stimulated with LPS. Similarly, ALX blockade reversed the beneficial effects of AT-RvD1 in DSS-induced colitis. To our knowledge, our findings showed for the first time the anti-inflammatory effects of resolvins of the D series and precursor 17R-HDHA in preventing experimental colitis. We also demonstrated the relevant role exerted by ALX activation on proresolving action of AT-RvD1. Moreover, AT-RvD1 showed a higher potency than 17R-HDHA and RvD2 in preventing DSS-induced colitis. The results suggest that these lipid mediators possess a greater efficacy when compared with other currently used IBD therapies, such as monoclonal anti-TNF, and have the potential to be used for treating IBD.

Cannabinoid receptor 2 (CB2) activation is suggested to trigger the peroxisome proliferator-activated receptor-␥ (PPAR␥) pathway, and agonists of both receptors improve colitis. Recently, the plant metabolite (E)-␤-caryophyllene (BCP) was shown to bind to and activate CB2. In this study, we examined the antiinflammatory effect of BCP in dextran sulfate sodium (DSS)-induced colitis and analyzed whether this effect was mediated by CB2 and PPAR␥. Oral treatment with BCP reduced disease activity, colonic macro-and microscopic damage, myeloperoxidase and N-acetylglucosaminidase activities, and levels and mRNA expression of colonic tumor necrosis factor-␣, IL-1␤, interferon-␥, and keratinocyte-derived chemokine. Inflammatory bowel diseases (IBDs) are a group of chronic diseases that affect the gastrointestinal tract and have been mainly subdivided as ulcerative colitis and Crohn's disease. 1 The IBDs are characterized by a strong leukocyte activation and infiltration into the intestinal tissues, the release of proinflammatory cytokines 2 and enzymes, and the formation of reactive oxygen species. All of these events can induce an extensive and unbalanced activation of the mucosal immune system, driven by the commensal flora. 3 Recent evidence suggests a role for the cannabinoid system in IBD regulation. Cannabinoid receptors 1 and 2 (CB1 and CB2) are expressed in normal human colon 4,5 and are up-regulated in IBD colonic tissue. In addition, an enhanced level of endocannabinoids was found in biopsy specimens from patients with ulcerative colitis. 5 It is thought that CB1 activation results in a decrease of intestinal hypermotility and hypersecretion, whereas the activation of CB2 results in the inhibition of proinflammatory mediators. In addition, both CB2 and CB1 knockout mice are more susceptible to the development of experimental colitis, and the activation of these receptors is extremely important for the abrogation of intestinal inflammation. 6 The role of CB2, however, is directly involved with innate immune system, because CB2 is primarily expressed in immune cells, such as macrophages, CD4 ϩ and CD8 ϩ T cells, monocytes, and polymorphonuclear neutro-

It has been previously reported that dietary fish oils, which are rich in the polyunsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid, can exert beneficial effects in inflammatory bowel disease. In this study, we investigated the effects of docosahexaenoic acid–derived lipid mediator maresin 1 (MaR1) in dextran sulfate sodium (DSS)– and 2,4,6-trinitrobenzenesulfonic acid–induced colitis in mice. Systemic treatment with MaR1 significantly attenuated both DSS- and 2,4,6-trinitrobenzene sulfonic acid–induced colonic inflammation by improving the disease activity index and reducing body weight loss and colonic tissue damage. MaR1 treatment also induced a significant decrease in levels of inflammatory mediators, such as IL-1β, TNF-α, IL-6, and IFN-γ, in the acute protocol, as well as IL-1β and IL-6, but not TNF-α and INF-γ, in the chronic DSS colitis protocol. Additionally, MaR1 decreased ICAM-1 mRNA expression in both the acute and chronic protocols of DSS-induced colitis. Furthermore, the beneficial effects of MaR1 seem to be associated with inhibition of the NF-κB pathway. Moreover, incubation of LPS-stimulated bone marrow–derived macrophage cultures with MaR1 reduced neutrophil migration and reactive oxygen species production, besides decreasing IL-1β, TNF-α, IL-6, and INF-γ production. Interestingly, macrophages incubated only with MaR1 showed a significant upregulation of mannose receptor C, type 1 mRNA expression, an M2 macrophage phenotype marker. These results indicate that MaR1 consistently protects mice against different models of experimental colitis, possibly by inhibiting the NF-κB pathway and consequently multiple inflammatory mediators, as well as by enhancing the macrophage M2 phenotype.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) caused by demyelination, immune cell infiltration, and axonal damage. Herein, we sought to investigate the influence of physical exercise on mice experimental autoimmune encephalomyelitis (EAE), a reported MS model. Data show that both strength and endurance training protocols consistently prevented clinical signs of EAE and decreased oxidative stress, an effect which was likely due to improving genomic antioxidant defense-nuclear factor erythroid 2-related factor (Nrf2)/antioxidant response elements (ARE) pathway-in the CNS. In addition, physical exercise inhibited the production of pro-inflammatory cytokines interferon (IFN)-γ, interleukin (IL)-17, and IL-1β in the spinal cord of mice with EAE. Of note, spleen cells obtained from strength training group incubated with MOG showed a significant upregulation of CD25 and IL-10 levels, with a decrease of IL-6, MCP-1, and tumor necrosis factor (TNF)-α production, mainly, during acute and chronic phase of EAE. Moreover, these immunomodulatory effects of exercise were associated with reduced expression of adhesion molecules, especially of platelet and endothelial cell adhesion molecule 1 (PECAM-1). Finally, physical exercise also restored the expression of tight junctions in spinal cord. Together, these results demonstrate that mild/moderate physical exercise, when performed regularly in mice, consistently attenuates the progression and pathological hallmarks of EAE, thereby representing an important non-pharmacological intervention for the improvement of immune-mediated diseases such as MS. Graphical Abstract Schematic diagram illustrating the beneficial effects of physical exercise during experimental model of MS. Physical exercise, especially strength (ST) and endurance (ET) training protocols, inhibits the development and progression of disease, measured by the mean maximal clinical score (1.5 and 1.0, respectively), with inhibition of 30 % and 50 %, respectively, based on the AUC, compared with EAEuntreated group. In addition, ST and ET decreased oxidative stress, possibly, through genomic antioxidant defense, Nrf2-Keap1 signaling pathway, in the CNS. Physical exercise inhibited the production of inflammatory cytokines, such as IFN-γ, IL-17 and IL-1β in the spinal cord after EAE induction, as well as spleen cells obtained from ST group showed a significant upregulation of regulatory T cell markers, such as CD25 and IL-10 levels, and blocked IL-6, MCP-1 and TNF-α production, mainly, during acute and chronic phase of EAE. Finally, these immunomodulatory effects of exercise were associated with inhibition of adhesion molecules and reestablishment of tight junctions expression in spinal cord tissue, thereby limiting BBB permeability and transmigration of autoreactive T cells to the CNS. NO, nitric oxide; GPx, glutathione peroxidase, GSH, glutathione; Nrf2, nuclear factor (erythroid-derived 2)-like 2; CNS, central nervous system; BBB, blood-brain barrier; IFN-g, interferon-gam...

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