JT002, a small molecule inhibitor of the NLRP3 inflammasome for the treatment of autoinflammatory disorders.

The NLRP3 inflammasome is an intracellular, multiprotein complex that promotes the auto-catalytic activation of caspase-1 and the subsequent maturation and secretion of the pro-inflammatory cytokines, IL-1β and IL-18. Persistent activation of the NLRP3 inflammasome has been implicated in the pathophysiology of a number of inflammatory and autoimmune diseases, including neuroinflammation, cardiovascular disease, non-alcoholic steatohepatitis, lupus nephritis and severe asthma. Here we describe the preclinical profile of JT002, a novel small molecule inhibitor of the NLRP3 inflammasome.

Therapeutic benefits of recombinant alpha1-antitrypsin IgG1 Fc-fusion protein in experimental emphysema.

Background: Alpha-1 antitrypsin (AAT) is a major serine protease inhibitor. AAT deficiency (AATD) is a genetic disorder characterized by early-onset severe emphysema. In well-selected AATD patients, therapy with plasma-derived AAT (pAAT), "augmentation therapy", provides modest clinical improvement but is perceived as cumbersome with weekly intravenous infusions.

Plasticity of Naturally Occurring Regulatory T Cells in Allergic Airway Disease Is Modulated by the Transcriptional Activity of .

The impact of naturally occurring regulatory T cells (nTregs) on the suppression or induction of lung allergic responses in mice depends on the nuclear environment and the production of the pro-inflammatory cytokine interleukin 6 (IL-6). These activities were shown to be different in nTregs derived from wild-type (WT) and CD8-deficient mice (CD8), with increased IL-6 levels in nTregs from CD8 mice in comparison to WT nTregs. Thus, identification of the molecular mechanisms regulating IL-6 production is critical to understanding the phenotypic plasticity of nTregs.

Dichotomous role of TGF-β controls inducible regulatory T-cell fate in allergic airway disease through Smad3 and TGF-β-activated kinase 1.

Background: Inducible CD4CD25 regulatory T (iTreg) cells can become pathogenic effector cells, enhancing lung allergic responses.

Objective: We aimed to define the underlying cellular and molecular pathways activated by TGF-β, which determine the suppressor or enhancing activities of iTreg cells.

Methods: Sensitized wild-type and CD8-deficient (CD8) mice were challenged with allergen.

Hypoxia enhances CD8 T2 cell-dependent airway hyperresponsiveness and inflammation through hypoxia-inducible factor 1α.

Background: CD8 type 2 cytotoxic T (T2) cells undergo transcriptional reprogramming to IL-13 production in the presence of IL-4 to become potent, steroid-insensitive, pathogenic effector cells in asthmatic patients and in mice in a model of experimental asthma. However, no studies have described the effects of hypoxia exposure on T2 cell differentiation.

Objective: We determined the effects of hypoxia exposure on IL-13-producing CD8 T2 cells.

Spectrum of T-lymphocyte activities regulating allergic lung inflammation.

Despite advances in the treatment of asthma, optimization of symptom control remains an unmet need in many patients. These patients, labeled severe asthma, are responsible for a substantial fraction of the disease burden. In these patients, research is needed to define the cellular and molecular pathways contributing to disease which in large part are refractory to corticosteroid treatment.

Forkhead box protein 3 demethylation is associated with tolerance induction in peanut-induced intestinal allergy.

Background: Regulatory T (Treg) cells play an essential role in the maintenance of immune homeostasis in allergic diseases.

Objectives: We sought to define the mechanisms underlying induction of tolerance to peanut protein and prevention of the development of peanut allergy.

Methods: High or low doses of peanut extract were administered to pups every day for 2 weeks before peanut sensitization and challenge.

Dysregulation of metabolic pathways in a mouse model of allergic asthma.

Background: Asthma is a complex lung disease resulting from the interplay of genetic and environmental factors. To understand the molecular changes that occur during the development of allergic asthma without genetic and environmental confounders, an experimental model of allergic asthma in mice was used. Our goals were to (1) identify changes at the small molecule level due to allergen exposure, (2) determine perturbed pathways due to disease, and (3) determine whether small molecule changes correlate with lung function.

Inducible and naturally occurring regulatory T cells enhance lung allergic responses through divergent transcriptional pathways.

Background: Regulatory T cells attenuate development of asthma in wild-type (WT) mice, with both naturally occurring regulatory T (nTreg) cells and inducible regulatory T (iTreg) cells exhibiting suppressive activity. When transferred into CD8-deficient (CD8) recipients, both cell types enhanced development of allergen-induced airway hyperresponsiveness.

Objective: We sought to determine whether the pathways leading to enhancement of lung allergic responses by transferred nTreg and iTreg cells differed.

1,25D3 prevents CD8(+)Tc2 skewing and asthma development through VDR binding changes to the Cyp11a1 promoter.

Effector CD8(+) T cells convert from IFN-γ(+) (Tc1) to IL-13(+) (Tc2) cells in the presence of IL-4. Underlying regulatory mechanisms are not fully defined. Here, we show that addition of 1,25D3, the active form of vitamin D3, during CD8(+) T-cell differentiation prevents IL-4-induced conversion to IL-13-producers.

JNK2 regulates the functional plasticity of naturally occurring T regulatory cells and the enhancement of lung allergic responses.

Glucocorticoid-induced TNFR family-related protein (GITR)-mediated activation of JNK was shown to regulate the suppressive activity of CD4(+)CD25(+) naturally occurring T regulatory cells (nTregs) in wild-type (WT) hosts. In this study, CD4(+)CD25(+) T cells were shown to be capable of becoming pathogenic effector cells in sensitized and challenged CD8(-/-) recipient mice. Only GITR-expressing CD4(+)CD25(+) T cells, but neither GITR knocked-in CD4(+)CD25(-) T cells nor GITR-silenced CD4(+)CD25(+) T cells, enhanced development of lung allergic responses.

Janus kinase 1/3 signaling pathways are key initiators of TH2 differentiation and lung allergic responses.

Background: Janus kinases (JAKs) are regulators of signaling through cytokine receptors. The importance of JAK1/3 signaling on TH2 differentiation and development of lung allergic responses has not been investigated.

Objective: We sought to examine a selective JAK1/3 inhibitor (R256) on differentiation of TH subsets in vitro and on development of ovalbumin (OVA)-induced airway hyperresponsiveness (AHR) and inflammation in an experimental model of asthma.

Stepwise epigenetic and phenotypic alterations poise CD8+ T cells to mediate airway hyperresponsiveness and inflammation.

The functional plasticity of CD8(+) T cells in an atopic environment, encompassing a spectrum from IFN-γ- to IL-13-producing cells, is pivotal in the development of allergic airway hyperresponsiveness and inflammation, and yet remains mechanistically undefined. We demonstrate that CD8(+) T cell IL-13 induction proceeded through a series of distinct IL-4/GATA3-regulated stages characterized by gene expression and epigenetic changes. In vivo, CD8(+) T cells exposed to an environment rich in IL-4 displayed epigenetic changes at the GATA3 and IL-13 promoter indicative of transcriptional activation and IL-13 production.

Sequential engagement of FcεRI on Mast Cells and Basophil Histamine H(4) Receptor and FcεRI in Allergic Rhinitis.

Histamine H(4) receptor (H(4)R)-deficient mice (H(4)R(-/-)), H(4)R antagonist-treated wild-type (WT) mice, and WT mice depleted of basophils failed to develop early (EPR) or late phase (LPR) nasal responses following allergen sensitization and challenge. Basophil transfer from WT but not H(4)R(-/-) mice restored the EPR and LPR in H(4)R(-/-) mice. Following passive sensitization with OVA-specific IgE, FcεRI(-/-) recipients of WT basophils plus OVA and histamine developed an EPR and LPR.

Loss of T regulatory cell suppression following signaling through glucocorticoid-induced tumor necrosis receptor (GITR) is dependent on c-Jun N-terminal kinase activation.

Naturally occurring Foxp3(+)CD4(+)CD25(+) T regulatory cell (nTreg)-mediated suppression of lung allergic responses is abrogated following ligation of glucocorticoid-induced tumor necrosis receptor (GITR) family-related protein. In vitro stimulation of nTregs with GITR ligand increased phosphorylation of c-Jun N-terminal kinase (JNK) but not extracellular signal-regulated protein kinase (ERK) or p38 MAPK. SP600125, a known JNK inhibitor, prevented GITR-mediated phosphorylation of JNK.

Low-dose lipopolysaccharide affects lung allergic responses by regulating Jagged1 expression on antigen-pulsed dendritic cells.

Background: Notch signaling pathways govern immune function and the regulation of Th1 and Th2 differentiation. We previously demonstrated essential interactions between Notch on CD4+ T cells and Jagged1 on antigen-presenting cells in Th2 differentiation for the full development of allergen-induced airway hyperresponsiveness (AHR) and allergic airway inflammation.

Methods: Bone marrow-derived dendritic cells (BMDCs) were differentiated and incubated with different preparations of ovalbumin (OVA), including lipopolysaccharide (LPS)-depleted and LPS-spiked preparations.

SLAP deficiency enhances number and function of regulatory T cells preventing chronic autoimmune arthritis in SKG mice.

To test if manipulating TCR complex-mediated signaling (TCR signaling) could treat autoimmune disease, we generated the double SKG Src-like adapter protein (SLAP) knockout (DSSKO) mouse model. The SKG mutation in ZAP70 and SLAP have opposing functions on the regulation of TCR signaling. The combination of these two mutations alters TCR signaling in the context of a defined genetic background, uniform environmental conditions, and a well-characterized signaling disruption.

CD8 regulates T regulatory cell production of IL-6 and maintains their suppressive phenotype in allergic lung disease.

Naturally occurring CD4(+)CD25(+)Foxp3(+) T regulatory cells (nTregs) regulate lung allergic responses through production of IL-10 and TGF-β. nTregs from CD8(-/-) mice failed to suppress lung allergic responses and were characterized by reduced levels of Foxp3, IL-10, and TGF-β, and high levels of IL-6. Administration of anti-IL-6 or anti-IL-6R to wild-type recipients prior to transfer of CD8(-/-) nTregs restored suppression.

Peanut-induced intestinal allergy is mediated through a mast cell-IgE-FcepsilonRI-IL-13 pathway.

Background: Although implicated in the disease, the specific contributions of FcepsilonRI and IL-13 to the pathogenesis of peanut-induced intestinal allergy are not well defined.

Objectives: We sought to determine the contributions of FcepsilonRI, IL-13, and mast cells to the development of intestinal mucosal responses in a murine model of peanut-induced intestinal allergy.

Methods: Sensitized wild-type (WT), FcepsilonRI-deficient (FcepsilonRI(-/-)), and mast cell-deficient (Kit(W-sh/W-sh)) mice received peanut orally every day for 1 week.

Effects of combination therapy with montelukast and carbocysteine in allergen-induced airway hyperresponsiveness and airway inflammation.

Background And Purpose: Montelukast and S-carbocysteine have been used in asthmatic patients as an anti-inflammatory or mucolytic agent respectively. S-carbocysteine also exhibits anti-inflammatory properties.

Experimental Approach: Ovalbumin (OVA) sensitized BALB/c mice were challenged with OVA for 3 days followed by single OVA re-challenge (secondary challenge) 2 weeks later.

Jagged1 on dendritic cells and Notch on CD4+ T cells initiate lung allergic responsiveness by inducing IL-4 production.

Jagged1, a Notch ligand, and Notch have been implicated in Th2 differentiation, but their role in initiating IL-4 production and Th2 differentiation in vivo and the development of allergic airway responses has not been defined. In this study, we show that Jagged1 is up-regulated on bone marrow-derived dendritic cells (BMDCs) pulsed with allergen and that the transfer of these BMDCs before allergen challenge induces airway hyperresponsiveness (AHR) and eosinophilic airway inflammation. Treatment of CD4(+) T cells with a gamma-secretase inhibitor (GSI), which inhibits Notch signaling, resulted in decreased cytokine production when the cells were cocultured with allergen-pulsed, Jagged1-expressing BMDCs and, after the transfer of allergen-pulsed BMDCs, IL-4-deficient (IL-4(-/-)) recipients of GSI-treated naive CD4(+) T cells developed lower levels of AHR, reduced numbers of eosinophils, and lower Th2 cytokine levels when challenged with allergen.

Antigen specificity is not required for modulation of lung allergic responses by naturally occurring regulatory T cells.

Naturally occurring Foxp3(+)CD4(+)CD25(+) T cells isolated from lungs of naive mice regulate lung allergic airway hyperresponsiveness, inflammation, levels of Th2 cytokines, and mucus production. OVA-specific (alphabetaTCR(+)) CD4(+)CD25(+) T cells suppressed ragweed-induced airway hyperresponsiveness and inflammation as did anti-TCR-treated OVA-specific CD4(+)CD25(+) T cells, suggesting that Ag-specificity was not required for expression of regulatory activities. Suppression was associated with increased levels of IL-10 and TGF-beta; decreased levels of IL-4, IL-5, and IL-13 in bronchoalveolar lavage fluid; and reduced recruitment and activation of CD8(+) T cells in the airways.

Vaccine-induced CD8+ T cell-dependent suppression of airway hyperresponsiveness and inflammation.

Suppressing the abnormalities associated with asthma has been difficult to accomplish using immunotherapy or vaccination once the disease is established. The effector cells necessary for effective immunization/vaccination and immunotherapy of asthma are also not well understood. Therefore, we vaccinated allergen (OVA)-sensitized mice to determine whether therapeutic immunization could suppress airway hyperresponsiveness (AHR) and inflammation and to identify key immune effector cells and cytokines.

Leukotriene B4 release from mast cells in IgE-mediated airway hyperresponsiveness and inflammation.

Previous studies have shown that leukotriene B4 (LTB4), a proinflammatory lipid mediator, is linked to the development of airway hyperresponsiveness through the accumulation of IL-13-producing CD8+ T cells, which express a high affinity receptor for LTB4, BLT1 (Miyahara et al., Am J Respir Crit Care Med 2005;172:161-167; J Immunol 2005;174:4979-4984). By using leukotriene A4 hydrolase-deficient (LTA4H-/-) mice, which fail to synthesize LTB4, we determined the role of this lipid mediator in allergen-induced airway responses.