Inflammatory bowel diseases (IBDs), mainly Crohn's disease and ulcerative colitis, are dynamic, chronic inflammatory conditions that are associated with an increased colon cancer risk. Inflammatory cell apoptosis is a key mechanism for regulating IBD. Peptidylarginine deiminases (PADs) catalyze the posttranslational conversion of peptidylarginine to peptidylcitrulline in a calcium-dependent, irreversible reaction and mediate the effects of proinflammatory cytokines. Because PAD levels are elevated in mouse and human colitis, we hypothesized that a novel small-molecule inhibitor of the PADs, i.e., chloramidine (Cl-amidine), could suppress colitis in a dextran sulfate sodium mouse model. Results are consistent with this hypothesis, as demonstrated by the finding that Cl-amidine treatment, both prophylactic and after the onset of disease, reduced the clinical signs and symptoms of colitis, without any indication of toxic side effects. Interestingly, Cl-amidine drives apoptosis of inflammatory cells in vitro and in vivo, providing a mechanism by which Cl-amidine suppresses colitis. In total, these data help validate the PADs as therapeutic targets for the treatment of IBD and further suggest Cl-amidine as a candidate therapy for this disease.

The role of NF-κB activation in tumor initiation has not been thoroughly investigated. We generated Ikkβ(EE) IEC

Background Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid produced by mast cells (MC) upon cross-linking of their high affinity receptors for IgE by antigen (Ag) that can amplify MC responses by binding to its S1P receptors. Acute MC-dependent allergic reaction can lead to systemic shock but the early events of its development in lung tissues have not been investigated, and S1P functions in the onset of allergic processes remain to be examined. Objective We used a highly specific neutralizing anti-S1P antibody (mAb) and an S1P receptor 2 (S1PR2) antagonist, JTE-013, to study S1P and S1PR2 signaling contributions to MC- and IgE-dependent airway allergic responses in mice within minutes after Ag challenge. Methods Allergic reaction was triggered by a single intraperitoneal (i.p.) dose of Ag in sensitized mice pre-treated i.p. with anti-S1P or isotype control mAb, or JTE-013 or vehicle prior to Ag challenge. Results Kinetics experiments revealed early pulmonary infiltration of mostly T cells around blood vessels of sensitized mice 20 minutes post-Ag exposure. Pre-treatment with anti-S1P mAb inhibited in vitro MC activation, as well as in vivo development of airway infiltration and MC activation, reducing serum levels of histamine, cytokines and the chemokines MCP-1/CCL2, MIP-1α/CCL3 and RANTES/CCL5. S1PR2 antagonism or deficiency, or MC deficiency recapitulated these results. Both in vitro and in vivo experiments demonstrated MC S1PR2 dependency for chemokine release and the necessity for signal transducer and activator of transcription 3 (Stat3) activation. Conclusion Activation of S1PR2 by S1P and downstream Stat3 signaling in MC regulate early T cell recruitment to antigen-challenged lungs by chemokine production.

Ulcerative colitis (UC) is a chronic inflammatory condition associated with a high colon cancer risk. We have previously reported that American Ginseng (AG) extract significantly reduced the inflammatory parameters of chemically induced colitis. The aim of this study was to further delineate the components of AG that suppress colitis and prevent colon cancer. Among five different fractions of AG (Butanol, Hexane, Ethylacetate, Dicholoromethane and Water), a Hexane Fraction has particularly potent anti-oxidant and pro-apoptotic properties. The effects of this fraction were shown in a mouse macrophage cell line (ANA-1 cells), in a human lymphoblastoid cell line (TK6), and in an ex-vivo model (CD4+/CD25− primary effector T cells). A key in vivo finding was that compared with the whole AG extract, the Hexane Fraction of AG was more potent in treating colitis in a dextran sulfate sodium (DSS) mouse model, as well as suppressing azoxymethane (AOM)/DSS-induced colon cancer. Furthermore, TUNEL labeling of inflammatory cells within the colonic mesenteric lymph nodes (MLN) was elevated in mice consuming DSS + the Hexane Fraction of AG. Results are consistent with our in vitro data, and with the hypothesis that the Hexane Fraction of AG has antiinflammatory properties, and drives inflammatory cell apoptosis in vivo, providing a mechanism by which this fraction protects from colitis in this DSS mouse model. This study moves us closer to understanding the molecular components of AG that suppress colitis, and prevent colon cancer associated with colitis.

Lactic acid (LA) is present in tumors, asthma, and wound healing, environments with elevated IL-33 and mast cell infiltration. While IL-33 is a potent mast cell activator, how LA affects IL-33-mediated mast cell function is unknown. To investigate this, mouse bone marrow-derived mast cells (BMMC) were cultured with or without LA and activated with IL-33. LA reduced IL-33-mediated cytokine and chemokine production. Using inhibitors for monocarboxylate transporters (MCT) or replacing LA with sodium lactate revealed that LA effects are MCT-1- and pH-dependent. LA selectively altered IL-33 signaling, suppressing TAK1, JNK, ERK, and NFκB phosphorylation, but not p38 phosphorylation. LA effects in other contexts have been linked to HIF-1α, which was enhanced in BMMC treated with LA. Since HIF-1α has been shown to regulate the microRNA miR-155 in other systems, LA effects on miR-155-5p and -3p species were measured. In fact, LA selectively suppressed miR-155-5p in a HIF-1α-dependent manner. Moreover, overexpressing miR-155-5p, but not miR-155-3p, abolished LA effects on IL-33-induced cytokine production. These in vitro effects of reducing cytokines were consistent in vivo, since LA injected intraperitoneally into C57BL/6 mice suppressed IL-33-induced plasma cytokine levels. Lastly, IL-33 effects on primary human mast cells were suppressed by LA in an MCT-dependent manner. Our data demonstrate that LA, present in inflammatory and malignant microenvironments, can alter mast cell behavior to suppress inflammation.