Inhibition Of IL-2 Production Research Articles

Impaired T cell-mediated hepatitis in peroxisome proliferator activated receptor alpha (PPAR\u03b1)-deficient mice

BackgroundPeroxisome proliferator activated receptor alpha (PPARα), a regulator of enzymes involved in β oxidation, has been reported to influence lymphocyte activation. The purpose of this study was to determine whether PPARα plays a role in T cell-mediated hepatitis induced by Concanavalin A (ConA).MethodsWild type (wt) or PPARα-deficient (PPARα−/−) mice were treated with ConA (15 mg/kg) by intravenous injection 0, 10 or 24 h prior to sacrifice and serum and tissue collection for analysis of tissue injury, cytokine response, T cell activation and characterization.ResultsTen and 24 h following ConA administration, wt mice had significant liver injury as demonstrated by serum transaminase levels, inflammatory cell infiltrate, hepatocyte apoptosis, and expression of several cytokines including interleukin 4 (IL4) and interferon gamma (IFNγ). In contrast, PPARα−/− mice were protected from ConA-induced liver injury with significant reductions in serum enzyme release, greatly reduced inflammatory cell infiltrate, hepatocellular apoptosis, and IFNγ expression, despite having similar levels of hepatic T cell activation and IL4 expression. This resistance to liver injury was correlated with reduced numbers of hepatic natural killer T (NKT) cells and their in vivo responsiveness to alpha-galactosylceramide. Interestingly, adoptive transfer of either wt or PPARα−/− splenocytes reconstituted ConA liver injury and cytokine production in lymphocyte-deficient, severe combined immunodeficient mice implicating PPARα within the liver, possibly through support of IL15 expression and/or suppression of IL12 production and not the lymphocyte as the key regulator of T cell activity and ConA-induced liver injury.ConclusionTaken together, these data suggest that PPARα within the liver plays an important role in ConA-mediated liver injury through regulation of NKT cell recruitment and/or survival.

Zinc ions have a potential to attenuate both Ni ion uptake and Ni ion-induced inflammation

Nickel ions (Ni2+) are eluted from various metallic materials, such as medical devices implanted in human tissues. Previous studies have shown that Ni2+ enters inflammatory cells inducing inflammation. However, the regulation of Ni2+ uptake in cells has not yet been reported in detail. In the present study, we investigated the effects of various divalent cations on Ni2+ uptake and Ni2+-induced interleukin (IL)-8 production in the human monocytic cell line, THP-1. We demonstrated that ZnCl2, MnCl2, and CoCl2 inhibited the Ni2+ uptake, while CuCl2, FeCl2, MgCl2, and divalent metal transporter (DMT)-1 inhibitor, Chlorazol Black, did not. Furthermore, ZnCl2 inhibited Ni2+-induced IL-8 production, correlating with the inhibition of Ni2+ uptake. These results suggested that Ni2+ uptake occurred through Zn2+, Mn2+, and Co2+-sensitive transporters and that the inhibition of Ni2+ uptake resulted in the inhibition of IL-8 production. Furthermore, using an Ni wire-implanted mouse model, we found that Ni wire-induced expression of mouse macrophage inflammatory protein-2 (MIP-2) and cyclooxygenase-2 (COX-2) mRNA in the skin tissue surrounding the wire were enhanced by low Zn conditions. These results suggested that the physiological concentration of Zn2+ modulates Ni2+ uptake by inflammatory cells, and a Zn deficient state might increase sensitivity to Ni.

LB976 Effects of TRP-regulin, pongamia oil and hesperidin methyl chalcone on anti-redness treatment

Rosacea is a chronic skin disorder characterized by inflammation and vascular abnormalities of the facial skin. Skin biopsies of rosacea are also characterized by an increase on the activation of the capsaicin receptor, the transient receptor potential vanilloid 1 (TRPV1). The aim of this study was to evaluate the activity of different compounds on the inflammatory and vascular responses implicated in rosacea. In one hand, the activity of Hesperidine Methyl Chalcone (HMC) compound was assessed to modulate vascular responses and IL-8 cytokine production after a Substance P (SP) stimulation on human skin explants. On the other hand, we evaluated the effect of TRP-regulin® (pentylene glycol 4-t-butylcyclohexanol) on TRPV1 activation, and the effect of the association of TRP-regulin® and pongamia oil on the inflammatory response of normal human epidermal keratinocytes (NHEK) in a rosacea environment. In the SP stimulated-skin model, HMC significantly decreased the proportion of dilated vessels, the total vessel area and the IL8 production. Moreover, we showed that TRP-regulin® significantly inhibited TRPV1 activation by capsaicin. Finally, we evaluated the effect of TRP-regulin®, pongamia oil and their association on the inflammatory response of NHEK in a rosacea environment. These experiments showed a synergy of these two compounds association on the inhibition of IL8 production. Altogether these results showed that HMC, TRP-regulin® and pongamia oil compounds have complementary and very interesting soothing and anti-redness properties and could be suitable for topical adjunctive treatment in rosacea.

Abstract 596: eFT508, a potent and highly selective inhibitor of MNK1/2 regulates immune checkpoint and cytokine expression promoting anti-tumor immunity

Abstract Dysregulated translation of messenger RNA (mRNA) plays a role in the pathogenesis of multiple solid tumors and hematological malignancies. MNK1 and MNK2 integrate signals from several oncogenic and immune signaling pathways (including RAS, Toll-like receptors and T cell receptor) by phosphorylating eukaryotic initiation factor 4E (eIF4E) and other key effector proteins including hnRNPA1 and PSF. Phosphorylation of these RNA-binding proteins by MNK1 and MNK2 selectively regulates the stability and translation of a subset of cellular mRNA that control tumor/stromal cell signaling, the tumor microenvironment and immune cell function. eFT508 is a potent and highly selective inhibitor of both MNK1 and MNK2. Ribosome profiling has demonstrated that inhibition of MNK1 and MNK2 by eFT508 selectively regulates the translational efficiency and mRNA stability of a subset of genes that include inflammatory cytokines/chemokines, regulators of stress response, and effectors of anti-tumor immune response. Given the importance of MAPK signaling and translational control to immune cell activation and differentiation, the immunological effect of eFT508 was further evaluated in both normal human immune cells in vitro and immunocompetent syngeneic cancer models in vivo. eFT508 treatment of normal donor T cells has no deleterious effect on αCD3/αCD28 stimulated IL-2 production, T cell proliferation or T cell viability. However, eFT508 selectively down regulates the induction of IL-10 and specific immune checkpoint receptors, including PD-1 and LAG3. Further evaluation of the mechanism of translational regulation has shown LAG3 mRNA contains specific sequence elements in the 5’-untranslated region (UTR) that confer sensitivity to eFT508. In addition, IL-10 mRNA is destabilized upon treatment with eFT508 leading to significant inhibition of IL-10 production in activated T cells. Furthermore, eFT508 treatment results in upregulation of MHC class II molecules on tumor cells, macrophage and dendritic cells through an IL-10/MARCH1 dependent mechanism. The in vivo antitumor effect of eFT508 was assessed in the CT26 BALB/C syngeneic tumor model. CT26 mouse tumor cell proliferation and survival are insensitive to eFT508 in vitro. In vivo, daily oral treatment with 1 mg/kg eFT508 results in significant anti-tumor activity, modulation of tumor infiltrating lymphocytes and establishment of immune memory. In addition, combination of eFT508 with either anti-PD-1 or anti-PD-L1 monoclonal antibodies results in marked efficacy, significantly increasing the percentage of responder animals. eFT508 is currently under evaluation in two phase I/II clinical trials for patients with advanced solid tumors and patients with advanced lymphoma respectively. These findings support further clinical evaluation of eFT508 in combination with checkpoint blockade. Citation Format: Kevin R. Webster, Vikas K. Goel, Jocelyn Staunton, Craig R. Stumpf, Rajesh Sharma, Ivy N. Hung, Gregory S. Parker, Jolene Molter, Gary G. Chiang, Christopher J. Wegerski, Samuel Sperry, Vera Huang, Joan Chen, Peggy A. Thompson, Chinh Tran, Justin T. Ernst, Paul A. Sprengeler, Siegfried H. Reich. eFT508, a potent and highly selective inhibitor of MNK1/2 regulates immune checkpoint and cytokine expression promoting anti-tumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 596. doi:10.1158/1538-7445.AM2017-596

Development of Anti-IL-1R3 Monoclonal Antibodies for Treating Cancer and IL-1 Family-Mediated Inflammation

IL-1R3 is the co-receptor required for signaling of IL-1β, IL-1α, IL-33 and IL-36α, β and γ. The naturally occurring IL-1 receptor antagonist (anakinra), is used to block IL-1β, and IL-1α and clinical trials have demonstrated a reduction in progression to multiple myeloma as well as increased overall survival in stage IV pancreatic cancer using anakinra. In addition, a monoclonal antibody that targets IL-1α increases overall survival in metastatic colorectal cancer. However, blocking IL-1R3 would reduce not only IL-1β and IL-1α but also IL-33 as well as IL-36α, β and γ. The data described below reveal the broad efficacy of anti-IL-1R3.In the present studies, monoclonal humanized anti-IL-1R3 antibodies were studied in the mixed leukocyte reaction (MLR), in peripheral mononuclear cells (PBMC) stimulated with LPS, heat-killed Candida albicans or anti-CD3/antiCD28 as well as in THP-1 cells, a cell line derived from a patient with acute myeloid leukemia (AML). In the MLR, anti-IL-1R3 at 5 µg/mL reduced IFNγ by 81% and IL-6 by 48% compared to 36% by anakinra. In LPS-stimulated PBMCs, IL-6 was reduced by 40% and 58% with anakinra and anti-IL-1R3 respectively. Using heat-killed Candida, the suppression of IL-6 production by anti-IL-1R3 was up to 70%, comparable to anakinra. Immuno-stimulation using anti-CD3/CD28 resulted in a similar inhibition capacity for anakinra (42%) and anti-IL-1R3 (45%) on IL-6 production also. Since neutralizing anti-IL-1α antibodies have increased overall survival in metastatic colorectal cancer, we also measured the effect of anti-IL-1R3 on intracellular levels of IL-1α. In PBMCs stimulated with LPS, the levels of IL-1α were reduced by 35% in cells cultured with anakinra at 10 µg/mL and by 66% in cells exposed to anti-IL-1R3 at same concentration. Activating PBMCs with anti-CD3/anti-CD28 led to a reduction in IL-1α by anakinra of 17%, whereas anti-IL-1R3 suppressed by 29%. We next examined the effect on THP-1 cells as a model for blocking IL-1 family members in AML. THP-1 were differentiated with phorbol myristate acetate (PMA) for 3 hours, washed and subsequently rested for 3 days. The cells were then stimulated with LPS for 3 hours and anti-IL-1R3 was added for 1 hour followed by inflammasome activation with ATP. The reduction in secretion of IL-1β was here 30% at 5 µg/mL of anti-IL-1R3.Collectively, these studies indicate that antibody blockade of IL-1R3 is effective in reducing cytokines from primary cells using in-vitro models of organ rejection, infection and immunostimulation. In THP-1 cells, the reduction in inflammasome-dependent IL-1β suggests that anti-IL-1R3 can be used to treat acute myeloid leukemia, or progression to multiple myeloma. Since anti-IL-1R3 inhibits the signaling through IL-1R1, both IL-1α and IL-1β are targeted by this antibody. Suggesting a future role for this antibody in not only AML, but also other cancer types dominated by IL-1 mediated inflammation, such as metastatic colorectal and pancreatic cancer. DisclosuresFischer:MAB Discovery GmbH: Employment. Pollyea:Ariad: Other: advisory board; Pfizer: Other: advisory board, Research Funding; Glycomimetics: Other: DSMB member; Alexion: Other: advisory board; Celgene: Other: advisory board, Research Funding.

Bach2-Batf interactions control Th2-type immune response by regulating the IL-4 amplification loop.

Although Bach2 has an important role in regulating the Th2-type immune response, the underlying molecular mechanisms remain unclear. We herein demonstrate that Bach2 associates with Batf and binds to the regulatory regions of the Th2 cytokine gene loci. The Bach2–Batf complex antagonizes the recruitment of the Batf–Irf4 complex to AP-1 motifs and suppresses Th2 cytokine production. Furthermore, we find that Bach2 regulates the Batf and Batf3 expressions via two distinct pathways. First, Bach2 suppresses the maintenance of the Batf and Batf3 expression through the inhibition of IL-4 production. Second, the Bach2–Batf complex directly binds to the Batf and Batf3 gene loci and reduces transcription by interfering with the Batf–Irf4 complex. These findings suggest that IL-4 and Batf form a positive feedback amplification loop to induce Th2 cell differentiation and the subsequent Th2-type immune response, and Bach2–Batf interactions are required to prevent an excessive Th2 response.

Targeted disruption of CK1α in Toxoplasma gondii increases acute virulence in mice

Toxoplasma gondii, the causative agent of toxoplasmosis, encodes two casein kinase 1 (CK1) isoforms, CK1α and CK1β, with only CK1α having enzyme activity. Here we investigated the biological role of CK1α by construction of a CK1α deletion mutant (Δck1α) based on the type I parasite, and complement the mutant with restored expression of CK1α. Deletion of CK1α resulted in markedly defective parasite replication in vitro. Infected mice with Δck1α parasite caused suppression of IL-12 production, severe liver damage, higher tissue burdens, and short survival time relative to the CK1α-positive parental strain. Western blot analysis revealed that deletion of CK1α led to increased activation of the signal transducer and activator of transcription (STAT)-3 in infected mice and bone marrow-derived microphages. The transcriptome analysis showed that deletion of CK1α may increase expression of rhoptry proteins (ROPs). Western blot showed enhanced expression of ROP16 in the Δck1α parasite as compared with the wild-type and complemented parasites. These findings demonstrated that deletion of CK1α may increase acute virulence of T. gondii in mice by increased expression of ROPs, activation of STAT3, and suppression of IL-12 production, which have important implications for elucidating regulation mechanism of virulence factors for T. gondii.

Discovery of oxa-sultams as RORc inverse agonists showing reduced lipophilicity, improved selectivity and favorable ADME properties

Modification of the δ-sultam ring of RORc inverse agonist 2 led to the discovery of more polar oxa-sultam 65. The less lipophilic inverse agonist (65) displayed high potency in a biochemical assay, which translated into inhibition of IL-17 production in human peripheral blood mononuclear cells. The successful reduction of lipophilicity of this new analog gave rise to additional improvements in ROR selectivity and aqueous kinetic solubility, as well as reduction in plasma protein binding, while maintaining high cellular permeability.

Abstract 3278: Dopamine inhibits growth of multiple myeloma

Abstract Introduction: Multiple myeloma (MM), progressive plasma cell tumor leading to overproduction of monoclonal immunoglobulins, osteolytic bone lesions, renal disease and immunodeficiency, is the second most prevalent hematologic malignancy in the United States. Vascular endothelial growth factor-A (VEGF-A) is a critical cytokine responsible for the induction of angiogenesis in several solid and hematological malignancies like MM. It is likely that VEGF-A induced bone marrow (BM) angiogenesis promotes the survival, growth and proliferation of MM .Therefore targeting BM angiogenesis in MM may be effective for the treatment of MM patients Objective/Hypothesis: Bone marrow stromal cells (BMSC) are believed to play a central role in progression of MM pathogenesis. Along with other factors, these cells overproduce IL-6 that in turn stimulates growth, survival and progression of MM cells. Since it has been shown that VEGF-A can stimulate IL-6 secretion by these cells and because we have demonstrated that neurotransmitter dopamine (DA) can inhibit VEGF-A functions by acting through its D2 receptors (D2R) and BMSC express DAD2R, we therefore hypothesize that DA or D2R agonists have a role in inhibiting VEGF-A mediated IL-6 secretion by BMSC and thereby, MM progression. Results: Our results indicate that VEGF-A can significantly increase the secretion of IL6 by isolated BMSC cells in vitro. Addition of DA or D2R agonist, quinpirole, to VEGF-A treated BM cells results in suppression of IL-6 production. However treatment with D2R antagonist, eticlopride, prior to treatment with DA results in abrogation of the effect of DA. Similar effects of DA on VEGF-A induced IL-6 secretion was also observed in HS-5 human BM stromal cells. Our results further indicate that VEGF-A induced VEGFR1 phosphorylation is suppressed in HS-5 cells on treatment with D2R agonist. Furthermore, DA also inhibits the proliferation of MM1.S human MM cells in vitro. Conclusion: DA may be a new and an effective approach to retard the progression of MM. Since anti-angiogenic monotherapy cannot eradicate the disease completely, strategies using DA with more traditional modalities to eradicate the disease at the time of initial treatment might be beneficial. Finally, DA or its D2R agonists are being used in the clinics for several years for the treatment of other disorders, therefore these inexpensive drugs (in comparison to presently available drugs for the treatment of MM) with known and manageable side effects can be used in the clinics in near future for the treatment of both early and late stage MM. Citation Format: Chandrani Sarkar, Debanjan Chakroborty, Sujit Basu. Dopamine inhibits growth of multiple myeloma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3278.

Discovery and optimization of 1,7-disubstituted-2,2-dimethyl-2,3-dihydroquinazolin-4(1H)-ones as potent and selective PKCθ inhibitors

A high-throughput screening campaign helped us to identify an initial lead compound (1) as a protein kinase C-θ (PKCθ) inhibitor. Using the docking model of compound 1 bound to PKCθ as a model, structure-based drug design was employed and two regions were identified that could be explored for further optimization, i.e., (a) a hydrophilic region around Thr442, unique to PKC family, in the inner part of the hinge region, and (b) a lipophilic region at the forefront of the ethyl moiety. Optimization of the hinge binder led us to find 1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one as a potent and selective hinge binder, which resulted in the discovery of compound 5. Filling the lipophilic region with a suitable lipophilic substituent boosted PKCθ inhibitory activity and led to the identification of compound 10. The co-crystal structure of compound 10 bound to PKCθ confirmed that both the hydrophilic and lipophilic regions were fully utilized. Further optimization of compound 10 led us to compound 14, which demonstrated an improved pharmacokinetic profile and inhibition of IL-2 production in a mouse.

New immunomodulatory steroidal alkaloids from Sarcococa saligna

Two new steroidal alkaloids, (20 S)-(bennzamido)-3β-(N,N-dimethyamino)-pregnane (1), and (20 S)-(bennzamido)-pregnane-3-one- (2), and two known steroidal alkaloids, pachysanaximine A (3) and 3β, 20α-diacetamido-5α-pregnane (4) were isolated from the whole plant of Sarcococca saligna. The structures of these compounds were identified with the help of spectroscopic techniques while spectra for known compounds were compared with spectra reported in literature. The immunomodulatory potential of the new compounds were found to be significant and dose dependent. Compound 1 showed inhibition of T cells proliferation at 10μg/mL (95%), and inhibition of IL-2 production with an IC50=1.6μg/mL.

Suppression of IL-10 production by activated B cells via a cell contact-dependent cyclooxygenase-2 pathway upregulated in IFN-γ-treated mesenchymal stem cells

The immunoregulatory properties of mesenchymal stem cells (MSCs) have been well documented in various models in vitro and in vivo. Furthermore, a population of regulatory B cells (Bregs) that produce relatively high concentrations of IL-10 has been recently described. To study the relationship between MSCs and Bregs, we analyzed the effects of MSCs on IL-10 production by lipopolysaccharide (LPS)-activated mouse B cells. The production of IL-10 by B cells remained preserved in the presence of MSCs and was even significantly enhanced by IFN-γ. However, the production of IL-10 was strongly suppressed in cultures containing MSCs and IFN-γ. Preincubation of MSCs, but not of B cells, with IFN-γ induced the suppression of IL-10 secretion in cultures containing MSCs and B cells. The supernatants from IFN-γ-treated MSCs had no inhibitory effect, and the suppression of IL-10 production was abrogated if the MSCs and B cells were separated in a transwell system. Analysis of the gene expression of IFN-γ- or IFN-γ and LPS-treated MSCs revealed a strong upregulation of genes for indoleamine-2,3-dioxygenase (IDO), cyclooxygenase-2 (Cox-2) and programmed cell death-ligand 1 (PD-L1). While the inhibition of IDO activity or the inclusion of the neutralization monoclonal antibody anti-PD-L1 did not abrogate the suppression, indomethacin, an inhibitor of Cox-2, completely inhibited the MSC-mediated suppression of IL-10 production. Accordingly, the production of IL-10 by B cells was inhibited by exogenous prostaglandin E2. The results thus suggest that IFN-γ-treated MSCs strongly inhibit IL-10 production by activated B cells by a mechanism requiring cell contact and involving the Cox-2 pathway.

Abstract 60: FcR + CD4 + T Cells as a Specific Subset of IL-17-producing Cells Controlled by BATF/IRF8: Novel Insights Into Etiology of Kawasaki Disease

Kawasaki disease (KD) is an acute vasculitis primarily involved coronary arteries of infants and children. Although more than 40 years have passed since the first description of the disease, its etiology remains unclear. Circulating interleukin 17 is increased in the acute stage of KD and expressed in the damaged coronary arterial wall from autopsies of children after KD. The aim of this study was to elucidate the involvement of IL-17 in the pathogenesis of KD. In this study, we identified a specific subset of CD4 + T cell expressing Fc receptor which existed high percentage in acute stage of KD than in recover stage. In addition, FcR + CD4 + T cell in acute stage expressed higher level of IL-17 than in recover stage. Therefore, we suggest this IL-17-producing FcR + CD4 + T cell may be a critical regulator of immunity in Kawasaki disease. In order to investigate the detail mechanism that FcR + CD4 + T cell subset expressed higher amount of IL-17 in KD, we isolated FcR - CD4 + and FcR + CD4 + T cells from adult healthy donors and stimulated with anti-CD3/CD28 beads only. We found that FcR + CD4 + T cells produced much higher IL-17 than FcR - CD4 + T cells without the need of Th17-differentiation cytokine. Furthermore, FcR + CD4 + T cells expressed higher IL-17-related transcriptional activator, BATF and lower level of transcriptional repress, IRF8 than FcR - CD4 + T cells. Knockdown of BATF and IRF8 could reduce and increase IL-17 production, respectively. These findings define BATF and IRF8 as the intrinsic transcriptional regulators in IL-17 production from FcR + CD4 + T cells. Collectively, our results suggest that IL-17-producing FcR + CD4 + T cells are the novel subset of IL-17-producing cells and important pathogenic immune cells in KD. Inhibition of IL-17 production from FcR + CD4 + T cells has great potential to be as a therapeutic strategy for Kawasaki disease and other FcR + CD4 + T cell-driven autoimmune diseases.

Erratum: WNT signalling in the immune system: WNT is spreading its wings

Nature Reviews Immunology 8, 581–593 (2008) On page 589 of this article, in the paragraph with the subheading “WNT signalling in antigen-presenting cells”, the authors state the following: “The functional role of WNT5A and its receptor Frizzled-5 during infection consisted of inhibition of the antigen-specific T helper 1 (TH1)-cell response, namely inhibition of IL-12 production and of the subsequent generation of interferon-γ (IFNγ)-producing T cells84”.

IL-25 regulates the polarization of macrophages and attenuates obliterative bronchiolitis in murine trachea transplantation models.

Obliterative bronchiolitis (OB) remains the major limitations for the long-term survival of allografts after lung transplantation. Th17 cells and IL-17 have been recognized as mediators of the development of OB in both animal models and human beings. IL-25, also called IL-17E, is the only anti-inflammatory cytokine of the IL-17 family, capable of regulating Th17 cells function in autoimmune inflammations. Whether IL-25 affects Th17 cells responses and the development of OB remains poorly understood. Acute rejection (AR) of the lung allograft has been regarded as the main problem for the development of OB, in which infiltrations of monocytes/macrophages play important roles. This study explored the potential role of IL-25 in regulation of macrophages polarization and inhibition of IL-17 production in the progression of OB. Here, we showed that IL-25 directly suppressed the expression of inflammatory cytokines, such as IL-6, IL-23, TNF-α, and IL-1β in LPS-induced pro-inflammatory M1 macrophages in vitro. In vivo data demonstrated that IL-25 deficiency promoted the polarization and function of M1 macrophages and aggravated the progression of OB in murine models of both orthotopic and heterotopic trachea transplantation. In conclusion, these data indicated that IL-25 attenuated OB by suppressing the function of M1 macrophages and IL-17 expression, providing an alternative strategy to intervene the development of OB.

Synthesis and biological evaluation of pyridazino[1′,6′:1,2]pyrido[3,4-b]indolinium and pyridazino[1,6-a]benzimidazolium salts as anti-inflammatory agents

Condensed polycyclic heteroaromatic cations bearing a bridgehead nitrogen with pyridazino[1′,6′:1,2]pyrido[3,4-b]indolinium and pyridazino[1,6-a]benzimidazolium structures were assayed as inhibitors of LPS-induced TNF-α production by THP-1 cells. The hit compound 1e, which had the best IC50 value (4.49 μM) and low toxicity, was further assayed on human PMBCs (IC50 3.91 μM) and monocytes (IC50 1.82 μM). This compound also inhibited TNF-α production following poly I:C stimulation of human monocytes and monocyte-derived dendritic cells; in the latter case, inhibition of IL-12 production was also observed. Compound 1e was also able to inhibit TNF-α expression at the transcriptional level and proved to be effective in vivo. Compound 1e is an interesting potential therapeutic agent in IMIDs.

Suppression of IL-2 production and proliferation of CD4(+) T cells by tuberostemonine O.

Tuberostemonine stereoisomers are natural alkaloids found in Stemona tuberosa, that are known to have anti-inflammatory and anti-infective properties. Tuberostemonine alkaloids inhibit inflammation by suppressing the expression of inflammatory mediators such as cyclooxygenase and nitric oxide synthase. However, the direct immunomodulatory properties of tuberostemonine alkaloids in T cells have not been elucidated so far. In this study, the activities in T cells of tuberostemonine N (TbN) and a novel alkaloid, tuberostemonine O (TbO), isolated from S. tuberosa, were investigated. Although TbN did not have a significant effect on cytokine production in splenic T cells, TbO selectively suppressed interleukin (IL)-2 production. Moreover, TbO, but not TbN, significantly inhibited IL-2 production by primary CD4(+) T cells and delayed the T-cell proliferation in a dose-dependent manner. Addition of excess recombinant IL-2 restored the decreased cell-division rates in TbO-treated CD4(+) T cells to control levels. Collectively, these findings suggest that the immunomodulatory effects of TbO occurred by the suppression of IL-2 expression and IL-2-induced T-cell proliferation, suggesting a potential beneficial role of tuberostemonine alkaloids for the control of chronic inflammatory and autoimmune diseases caused by hyperactivated T cells.

A novel function of interferon regulatory factor-1: inhibition of Th2 cells by down-regulating the Il4 gene during Listeria infection.

Infection with certain pathogens induces a shift of the Th subset balance to a Th1 dominant state. This, in turn, results in the suppression of Th2 responses. We focused on the involvement of interferon regulatory factor-1 (IRF-1) in the suppression of Th2 cells during Listeria infection. We found that the inhibition of IL-4 production by Th2 cells is mediated by a soluble factor (LmSN) produced by Listeria-infected antigen-presenting cells. The inhibition is not observed with T cells from Irf1 gene-targeted mice. IRF-1 suppresses transcription of the Il4 gene in Th2 cells. Under the influence of the LmSN, IRF-1 binds to the 3' untranslated region (UTR) region of the Il4 gene and down-regulates Il4 gene transcription. Finally, we identified IL-1α and IL-1β as the mediator of the LmSN activity. Signaling through IL-1R induces the stabilization and/or nuclear translocation of IRF-1. We propose that IRF-1 functions to induce the T-cell subset shift via a novel mechanism. Under the influence of IL-1, IRF-1 translocates into the nucleus and acts on the 3'UTR region of the Il4 gene, thus inhibiting its transcription in Th2 cells. As a result, the immune system shifts predominantly to a Th1 response during Listeria infection, resulting in effective protection of the host.

Platelet Factor 4 Protects Kidney Allograft in a Rat Kidney Transplantation Model

Platelets are the cellular mediator of thrombosis, but it is becoming increasingly evident that platelets actively participate in inflammation and immune responses. A recent paper indicated that platelet factor 4 (PF4) alleviated cardiac allograft rejection in mice. But the role of PF4 on kidney transplantation has never been investigated. In our current experiment, PF4 administration alleviates immune responses to kidney transplantation. PF4 significantly alleviates vascular and glomerular changes, as well as interstitial inflammation, fibrosis, and tubular atrophy at day 56 after transplantation. PF4 decreases interleukin (IL)-17 production in vivo and also limits Th17 differentiation in vitro. Furthermore, the alleviated chronic vasculopathy and tubulointerstitial inflammation induced by PF4 were abolished with additional IL-17 administration. Meanwhile, decreased serum creatinine and urea induced by PF4 were also reversed by recombinant mouse IL-17 (rmIL-17). In conclusion, PF4 plays a protective role in chronic kidney allograft and this was associated with inhibition of IL-17 production.

Lactobacillus rhamnosus L34 and Lactobacillus casei L39 suppress Clostridium difficile-induced IL-8 production by colonic epithelial cells.

BackgroundClostridium difficile is the main cause of hospital-acquired diarrhea and colitis known as C. difficile-associated disease (CDAD).With increased severity and failure of treatment in CDAD, new approaches for prevention and treatment, such as the use of probiotics, are needed. Since the pathogenesis of CDAD involves an inflammatory response with a massive influx of neutrophils recruited by interleukin (IL)-8, this study aimed to investigate the probiotic effects of Lactobacillus spp. on the suppression of IL-8 production in response to C. difficile infection.ResultsWe screened Lactobacillus conditioned media from 34 infant fecal isolates for the ability to suppress C. difficile-induced IL-8 production from HT-29 cells. Factors produced by two vancomycin-resistant lactobacilli, L. rhamnosus L34 (LR-L34) and L.casei L39 (LC-L39), suppressed the secretion and transcription of IL-8 without inhibiting C. difficile viability or toxin production. Conditioned media from LR-L34 suppressed the activation of phospho-NF-κB with no effect on phospho-c-Jun. However, LC-L39 conditioned media suppressed the activation of both phospho-NF-κB and phospho-c-Jun. Conditioned media from LR-L34 and LC-L39 also decreased the production of C. difficile-induced GM-CSF in HT-29 cells. Immunomodulatory factors present in the conditioned media of both LR-L34 and LC-L39 are heat-stable up to 100°C and > 100 kDa in size.ConclusionsOur results suggest that L. rhamnosus L34 and L. casei L39 each produce factors capable of modulating inflammation stimulated by C. difficile. These vancomycin-resistant Lactobacillus strains are potential probiotics for treating or preventing CDAD.