Marina Gomes Miranda e Castor

Treatment with a novel chemokine-binding protein or eosinophil lineage-ablation protects mice from experimental colitis

Eosinophils are multifunctional leukocytes implicated in numerous inflammatory diseases. The present study was conducted to clarify the precise role of eosinophils in the development of colitis by using eosinophil-depleted mice and a novel chemokine-binding protein that neutralizes CCL11 action. Colitis was induced by administration of dextran sodium sulfate (DSS) to wild-type and eosinophil-deficient DeltadblGATA-1 mice. Accumulation of eosinophils in the gut of mice given DSS paralleled worsening of clinical score and weight loss. In response to DSS, DeltadblGATA-1 mice showed virtual absence of eosinophil recruitment, amelioration of clinical score, weight loss, and tissue destruction, and no lethality. There was a decrease in CXCL1 and CCL3 production and decreased neutrophil influx in the intestine of DeltadblGATA-1 mice. Transfer of bone marrow cells from wild-type mice reconstituted disease manifestation in DSS-treated DeltadblGATA-1 mice, and levels of CCL11 were increased after DSS treatment and localized to inflammatory cells. Treatment with the chemokine-binding protein evasin-4 at a dose that prevented the function of CCL11 greatly ameliorated clinical score, weight loss, overall tissue destruction, and death rates. In conclusion, the influx of eosinophils is critical for the induction of colitis by DSS. Treatment with a novel chemokine-binding protein decreased eosinophil influx and greatly ameliorated colitis, suggesting that strategies that interfere with the recruitment of eosinophils may be useful as therapy for colitis.

Encapsulated mesenchymal stem cells for in vivo immunomodulation

Acute myeloid leukemia with biallelic CEBPA gene mutations and normal karyotype represents a distinct genetic entity associated with a favorable clinical outcome. J Clin Oncol 2010; 28: 570–577. 11 Döhner K, Tobis K, Ulrich R, Fröhling S, Benner A, Schlenk RF et al. Prognostic significance of partial tandem duplications of the MLL gene in adult patients 16 to 60 years old with acute myeloid leukemia and normal cytogenetics: a study of the Acute Myeloid Leukemia Study Group Ulm. J Clin Oncol 2002; 20: 3254–3261. 12 Schlenk RF, Döhner K, Krauter J, Fröhling S, Corbacioglu A, Bullinger L et al. Mutations and treatment outcome in cytogenetically normal acute myeloid leukemia. N Engl J Med 2008; 358: 1909–1918. 13 Haferlach C, Mecucci C, Schnittger S, Kohlmann A, Mancini M, Cuneo A et al. AML with mutated NPM1 carrying a normal or aberrant karyotype show overlapping biologic, pathologic, immunophenotypic, and prognostic features. Blood 2009; 114: 3024–3032. 14 Grossmann V, Schnittger S, Schindela S, Klein HU, Eder C, Dugas M et al. Strategy for robust detection of insertions, deletions, and point mutations in CEBPA, a GC-rich content gene, using 454 next-generation deep-sequencing technology. J Mol Diagn 2011; 13: 129–136. 15 Schnittger S, Alpermann T, Eder C, Schindela S, Grossmann V, Kern W et al. The role of different genetic subtypes in CEBPA mutated AML. Blood (ASH Ann Meet) 2010; 116: 752 (Abstracts: oral presentation).

The CCL3/Macrophage Inflammatory Protein-1α–Binding Protein Evasin-1 Protects from Graft-versus-Host Disease but Does Not Modify Graft-versus-Leukemia in Mice

CCL3 is a protein of the CC chemokine family known to be important for T cell recruitment in inflammatory diseases. The aim of the current study was to evaluate the effects and putative mechanism of action of evasin-1, a novel CCL3-binding protein, in the pathogenesis of acute graft-versus-host disease (GVHD). GVHD was induced by the transplantation of splenocytes from C57BL/6J to B6D2F1 mice. Treatment of recipient mice with evasin-1 prevented mortality associated with GVHD. This was correlated with reduced weight loss and clinical disease severity. Analysis of the small intestine showed that evasin-1 treatment reduced the histopathological score and decreased levels of IFN-γ and CCL5. Mechanistically, evasin-1 treatment reduced the number of CD4+ and CD8+ T cells infiltrating the small intestine, as assessed by immunohistochemistry, and the adhesion of leukocytes to intestinal venules of recipient mice, as assessed by intravital microscopy. Evasin-1 was also able to decrease liver damage, as seen by reduction of inflammatory infiltrate and IFN-γ levels. Treatment with evasin-1 did not interfere with graft-versus-leukemia. Altogether, our studies demonstrate that CCL3 plays a major role in mediating GVHD, but not graft-versus-leukemia in mice and suggest that blockade of CCL3 with evasin-1 has potential therapeutic application in patients undergoing bone marrow transplantation.

Control of murine Ly6C(high) monocyte traffic and immunosuppressive activities by atypical chemokine receptor D6.

The atypical chemokine receptor D6 is a decoy and scavenger receptor for most inflammatory CC chemokines and prevents the development of exacerbated inflammatory reactions. Here we report that mice lacking D6 expression in the nonhematopoietic compartment have a selective increase in the number of Ly6C(high) monocytes in the circulation and in secondary lymphoid tissues. Under inflammatory conditions, Ly6C(high) monocytes accumulate in increased number in secondary lymphoid organs of D6(-/-) mice in a CCR2-dependent manner. Ly6C(high) monocytes derived from D6(-/-) mice have enhanced immunosuppressive activity, inhibit the development of adaptive immune responses, and partially protect mice from the development of GVHD. Thus, control of CCR2 ligands by D6 regulates the traffic of Ly6C(high) monocytes and controls their immunosuppressive potential.

PI3Kγ controls leukocyte recruitment, tissue injury, and lethality in a model of graft-versus-host disease in mice

PI3Kγ is thought to mediate leukocyte migration to injured tissues and may be important in the pathogenesis of various T‐lymphocyte‐dependent pathologies, including autoimmune and inflammatory diseases. The present study evaluated the relevance of PI3Kγ in donor cells for the pathogenesis of acute GVHD using a model of adoptive transfer of splenocytes from WT or PI3Kγ−/− C57BL/6J mice to B6D2F1 mice, and mice that received PI3Kγ−/− cells showed reduced clinical signs of disease, bacterial translocation, tissue injury, and lethality rates. This was associated with reduced production of proinflammatory cytokines and chemokines (TNF‐α, IFN‐γ, CCL2, CCL3, and CCL5) and reduced infiltration of CD8+, CD4+, and CD11c+ cells in the small intestine. Mechanistically, in addition to decreasing production of proinflammatory mediators, absence or pharmacological blockade of PI3Kγ was associated with decreased rolling and adhesion of leukocytes to the mesenteric microcirculation, as assessed by intravital microscopy. Despite decreased GVHD, there was maintained GVL activity when PI3Kγ−/− leukocytes were transferred into WT mice. In conclusion, PI3Kγ plays a critical role in GVHD by mediating leukocyte influx and activation in tissues. PI3Kγ inhibitors may be useful in the treatment of GVHD in patients undergoing BMT.

The role of chemokines in mediating graft versus host disease: opportunities for novel therapeutics.

Bone marrow transplantation (BMT) is the current therapy of choice for several malignancies and severe autoimmune diseases. Graft versus host disease (GVHD) is the major complication associated with BMT. T lymphocytes and other leukocytes migrate into target organs during GVHD, become activated and mediate tissue damage. Chemokines are well known inducers of leukocyte trafficking and activation and contribute to the pathogenesis of GVHD. Here, we review the major animal models used to study GVHD and the role of chemokines in mediating tissue damage in these models. The role of these molecules in promoting potential beneficial effects of the graft, especially graft versus leukemia, is also discussed. Finally, the various pharmacological strategies to block the chemokine system or downstream signaling events in the context of GVHD are discussed.

Platelet-activating factor receptor plays a role in the pathogenesis of graft-versus- host disease by regulating leukocyte recruitment, tissue injury, and lethality

PAF is a potent lipid mediator involved in several manifestations of acute inflammation, including leukocyte influx, leukocyte interaction with endothelium, and production of inflammatory cytokines. The present study evaluated the relevance of PAFR for the pathogenesis of acute GVHD using a model of adoptive transfer of splenocytes from WT or PAFR−/− C57BL/6J to B6D2F1 mice. Mice, which received PAFR−/− splenocytes or treatment with the PAFR antagonist, showed reduced clinical signs of disease and no mortality. In GVHD mice receiving PAFR−/− splenocytes, there was deceased bacterial translocation and tissue injury. Furthermore, production of proinflammatory cytokines and chemokines (TNF‐α, IFN‐γ, CCL2, CCL3, and CCL5) and accumulation of CD8+ cells in intestine and liver were reduced in mice transplanted with the PAFR−/− splenocyte. Mechanistically, an absence or pharmacological blockade of PAFR was associated with decreased rolling and adhesion of leukocytes to the mesenteric microcirculation, as assessed by intravital microscopy. Despite decreased GVHD, there was maintained GVL activity when PAFR−/− leukocytes were transferred into WT mice. In conclusion, PAFR on donor leukocytes plays a critical role in GVHD by mediating leukocyte influx and cytokine production in target tissues. PAFR antagonist may potentially be useful in the treatment of GVHD in bone marrow‐transplanted patients.

Lithothamnion muelleri Controls Inflammatory Responses, Target Organ Injury and Lethality Associated with Graft-versus-Host Disease in Mice

Lithothamnion muelleri (Hapalidiaceae) is a marine red alga, which is a member of a group of algae with anti-inflammatory, antitumor, and immunomodulatory properties. The present study evaluated the effects of treatment with Lithothamnion muelleri extract (LM) in a model of acute graft-versus-host disease (GVHD), using a model of adoptive splenocyte transfer from C57BL/6 donors into B6D2F1 recipient mice. Mice treated with LM showed reduced clinical signs of disease and mortality when compared with untreated mice. LM-treated mice had reduced tissue injury, less bacterial translocation, and decreased levels of proinflammatory cytokines and chemokines (interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), chemokine (C-C motif) ligand 2 (CCL2), chemokine (C-C motif) ligand 3 (CCL3) and chemokine (C-C motif) ligand 5 (CCL5)). The polysaccharide-rich fraction derived from LM could inhibit leukocyte rolling and adhesion in intestinal venules, as assessed by intravital microscopy. LM treatment did not impair the beneficial effects of graft-versus-leukaemia (GVL). Altogether, our studies suggest that treatment with Lithothamnion muelleri has a potential therapeutic application in GVHD treatment.

NSAIDs induce peripheral antinociception by interaction with the adrenergic system

AIMS We evaluated the role of adrenergic systems on the peripheral antinociception induced by dipyrone and diclofenac. Mainmethods: The rat pawpressure test, inwhich sensitivity is increased by intraplantar injection of prostaglandin E2, was used to examine the peripheral effects of locally administered drugs. KEY FINDINGS Dipyrone (10, 20 and 40 μg) and diclofenac (5, 10 and 20 μg) administered locally into the right paw elicited a dose-dependent antinociceptive effect, which was demonstrated to be local; the injection of drugs into the ipsilateral and contralateral hindpaws demonstrated an effect only in the ipsilateral paw because only the treated paw produced an antinociceptive effect. To test the adrenergic system, we used guanethidine (30 mg/kg) to deplete noradrenalin from noradrenergic vesicles. Guanethidine antagonized the peripheral antinociception induced by diclofenac and dipyrone. Yohimbine (2.5, 5, 10, or 20 μg/paw) a nonselective α2-adrenergic receptor antagonist antagonized the peripheral antinociception induced by diclofenac (20 μg/paw) and dipyrone (40 μg/paw). Rauwolscine (Rau; 10, 15, 20 μg), a selective α2C-adrenoreceptor, was able to block the peripheral antinociception induced by NSAIDs. The other specific α2A,B and D-adrenoreceptor antagonists (BRL 44480, imiloxan and RX 821002, respectively) did not modify the peripheral antinociception. However, prazosin (0.5, 1, and 2 μg/paw), an α1 receptor antagonist, and propranolol (0.3, 0.6 or 1.2 μg/paw), a β-adrenoreceptor antagonist, antagonized the antinociception induced by diclofenac (20 μg/paw) and dipyrone (40 μg/paw). SIGNIFICANCE Dipyrone and diclofenac produce peripheral antinociception, which involves the release of NA and interaction with α1, α2C and β-adrenoreceptors.

Angiotensin-(1-7) through Mas receptor activation induces peripheral antinociception by interaction with adrenoreceptors.

Angiotensin-(1-7) [Ang-(1-7)] develops its functions interacting with Mas receptor. Mas receptor was recently identified in the DRG and its activation by Ang-(1-7) resulted in peripheral antinociception against PGE2 hyperalgesia in an opioid-independent pathway. Nevertheless, the mechanism by which Ang-(1-7) induce peripheral antinociception was not yet elucidated. Considering that endogenous noradrenaline could induce antinociceptive effects by activation of the adrenoceptors the aim of this study was verify if the Ang-(1-7) is able to induce peripheral antinociception by interacting with the endogenous noradrenergic system. Hyperalgesia was induced by intraplantar injection of prostaglandin E2 (2μg). Ang-(1-7) was administered locally into the right hindpaw alone and after either agents, α2-adrenoceptor antagonist, yohimbine (5, 10 and 20 μg/paw), α2C-adrenoceptor antagonist rauwolscine (10, 15 and 20 μg/paw), α1-adrenoceptor antagonist prazosin (0.5, 1 and 2 μg/paw), β-adrenoceptor antagonist propranolol (150, 300 and 600 ng/paw). Noradrenaline (NA) reuptake inhibitor reboxetine (30 μg/paw) was administered prior to Ang-(1-7) low dose (20 ng) and guanetidine 3 days prior to experiment (30 mg/kg/animal, once a day), depleting NA storage. Intraplantar Ang-(1-7) induced peripheral antinociception against hyperalgesia induced by PGE2. This effect was reversed, in dose dependent manner, by intraplantar injection of yohimbine, rauwolscine, prazosin and propranolol. Reboxetine intensified the antinociceptive effects of low-dose of Ang-(1-7) and guanethidine, which depletes peripheral sympathomimetic amines, reversed almost 70% the Ang-(1-7)-induced peripheral antinociception. Then, this study provides evidence that Ang-(1-7) induce peripheral antinociception stimulating an endogenous noradrenaline release that activates peripheral adrenoceptors inducing antinociception.