Structure-activity relationship study, target identification, and pharmacological characterization of a small molecular IL-12/23 inhibitor, APY0201.

Interleukin-12 (IL-12) and IL-23 are proinflammatory cytokines and therapeutic targets for inflammatory and autoimmune diseases, including inflammatory bowel diseases, psoriasis, rheumatoid arthritis, and multiple sclerosis. We describe the discovery of APY0201, a unique small molecular IL-12/23 production inhibitor, from activated macrophages and monocytes, and demonstrate ameliorated inflammation in an experimental model of colitis. Through a chemical proteomics approach using a highly sensitive direct nanoflow LC-MS/MS system and bait compounds equipped with the FLAG epitope associated regulator of PIKfyve (ArPIKfyve) was detected. Further study identified its associated protein phosphoinositide kinase, FYVE finger-containing (PIKfyve), as the target protein of APY0201, which was characterized as a potent, highly selective, ATP-competitive PIKfyve inhibitor that interrupts the conversion of phosphatidylinositol 3-phosphate (PtdIns3P) to PtdIns(3,5)P2. These results elucidate the function of PIKfyve kinase in the IL-12/23 production pathway and in IL-12/23-driven inflammatory disease pathologies to provide a compelling rationale for targeting PIKfyve kinase in inflammatory and autoimmune diseases.

RCAI-61 and related 6'-modified analogs of KRN7000: their synthesis and bioactivity for mouse lymphocytes to produce interferon-γ in vivo.

We synthesized ten new analogs of 6'-modified KRN7000 (A): RCAI-58, 61, 64, 83, 85-87, 113, 119, and 125. They could be synthesized by α-selective galactosylation of ceramide 9 with the 6-modified D-galactopyranosyl fluorides (8a-8f) or L-arabinopyranosyl fluoride (17), or by etherification of the known alcohol 19. Bioassay of the ten analogs demonstrated that RCAI-61 (1, 6'-O-methylated analog of A) was the most potent immunostimulant among them, and could induce the production of a large amount of IFN-γ even at a low concentration in mice in vivo.

Pyridone 6, a pan-JAK inhibitor, ameliorates allergic skin inflammation of NC/Nga mice via suppression of Th2 and enhancement of Th17.

Atopic dermatitis (AD) is a common pruritic inflammatory disease triggered by a defective skin barrier and immunodysregulation. AD has been considered a typical example of a Th2 response associated with allergic disease. In the early phases of the disease, symptoms include IgE hyperproduction, eosinophil accumulation, and mast cell activation; in the chronic phase, a Th1-dominant immune response is also observed at the sites of AD skin lesions. The role of IL-17-producing Th (Th17) cells in AD has not been established. In the current study, we found that pyridone 6 (P6), a pan-JAK inhibitor, delayed the onset and reduced the magnitude of skin disease in an AD-like skin-disease model of NC/Nga mice. P6 reduced IFN-γ and IL-13, whereas it enhanced IL-17 and IL-22 expression. In vitro, P6 also inhibited both Th1 and Th2 development, whereas it promoted Th17 differentiation from naive T cells when present within a certain range of concentrations. This was probably because P6 strongly inhibited STAT1, STAT5, and STAT6 phosphorylation, whereas STAT3 phosphorylation was less efficiently suppressed by P6 at the same concentration. Furthermore, IL-22 protects keratinocytes from apoptosis induced by IFN-γ, and administration of IL-17 and IL-22 partially ameliorated skin diseases in NC/Nga mice. These results suggested that the JAK inhibitor P6 is therapeutic for AD by modulating the balance of Th2 and Th17.

Synthesis and biological activity of ester and ether analogues of alpha-galactosylceramide (KRN7000).

Alpha-Galactosylceramide (alphaGalCer, KRN7000) has been identified as a modulator of immunological processes through its capacity to bind iNKT cells mediated by CD1d molecules. Some analogues in while the amide group in alphaGalCer is replaced with ester or ether groups were synthesized from d-arabinitol or l-ribose to evaluate their ability to activate iNKT cells. Ester analogues 30a, 31a, and 61 showed activity for IFNgamma and IL-4 production of iNKT cells, while ether (31b) and 4-methoxy ester (76) analogues of alpha-galactosylceramide were not active for iNKT cells.

Induction of Th1-biased cytokine production by alpha-carba-GalCer, a neoglycolipid ligand for NKT cells.

NKT cells are characterized by their production of both T(h)1 and T(h)2 cytokines immediately after stimulation with alpha-galactosylceramide (alpha-GalCer), which is composed of alpha-galactopyranose linked to ceramide (itself composed of sphingosine and fatty-acyl chains); the chain length of the ceramide varies and this affects the ability of alpha-GalCer to stimulate cytokine production. However, the contribution of its galactopyranose sugar moiety remains unclear. We synthesized alpha-carba-GalCer, which has an alpha-linked carba-galactosyl moiety; here, the 5a'-oxygen atom of the D-galactopyranose ring of alpha-GalCer is replaced by a methylene group. The alpha-carba-GalCer was more stable and showed higher affinity to the NKT receptor. It thus enhanced and prolonged production of IL-12 and IFN-gamma compared with alpha-GalCer, resulting in augmented NKT cell-mediated adjuvant effects in vivo. The alpha-carba-GalCer, which has an ether linkage, was more resistant to degradation by liver microsomes than was alpha-GalCer, which has an acetal bond. Modulation of the sugar moiety in glycolipids might therefore provide optimal therapeutic reagents for protective immune responses against tumor or pathogens.

SOCS3 in T and NKT cells negatively regulates cytokine production and ameliorates ConA-induced hepatitis.

Suppressor of cytokine signaling 3 (SOCS3), a negative-feedback molecule for cytokine signaling, has been implicated in protection against liver injury. Previous studies have shown that overexpression of SOCS3 in the liver by adenovirus or membrane permeable recombinant protein protected the liver from various injuries. However it remained uncertain in which type of cells SOCS3 suppresses liver injury. In this study, we demonstrated that forced expression of SOCS3 in T and NKT cells suppressed ConA-induced hepatitis using T and NKT cell-specific SOCS3 transgenic (Lck-SOCS3 Tg) mice. IFN-gamma and IL-4 production was reduced in Lck-SOCS3 Tg mice as well as splenocytes treated with ConA. IFN-gamma and IL-4 levels were also reduced in Lck-SOCS3 Tg mice administrated with alpha-galactosylceramide, suggesting that SOCS3 in NKT cells has suppressive function. Sustained expression of SOCS3 in an NKT cell line also resulted in reduced expression of various cytokines and transcription factors. In contrast, T and NKT cell-specific SOCS3 conditional knockout (Lck-SOCS3 cKO) mice were hypersensitive to ConA-mediated hepatitis. Isolated SOCS3-deficient NKT cells produced higher levels of IFN-gamma and IL-4. These data indicate that SOCS3 plays a negative regulatory role in NKT cell activation and that forced expression of SOCS3 in NKT cells is effective in preventing hepatitis.

RCAI-37, 56, 59, 60, 92, 101, and 102, cyclitol and carbasugar analogs of KRN7000: their synthesis and bioactivity for mouse lymphocytes to produce Th1-biased cytokines.

Cyclitol [RCAI-37 (1), 59 (5), 92 (7), and 102 (2)] and carbasugar analogs [RCAI-56 (3), 60 (4), and 101 (6)] of KRN7000 were synthesized through coupling reactions of the corresponding cyclitol or carbasugar derivatives with a cyclic sulfamidate (9) as the key step. Bioassay showed RCAI-56 (3, carbagalactose analog of KRN7000), 59 (5, 1-deoxy-neo-inositol analog), and 92 (7, 1-O-methylated 5) to be remarkably potent stimulants of mouse lymphocytes to produce Th1-biased cytokines, such as interferon-gamma, in vivo. RCAI-60 (4, carbafucose analog) and RCAI-101 (6, 6-O-methylated 3) showed strong bioactivity, on the other hands, RCAI-37 (1, myo-inositol analog) and 102 (2, neo-inositol analog) induced little cytokine production.

Pivotal role of cerebral interleukin-17-producing gammadeltaT cells in the delayed phase of ischemic brain injury.

Lymphocyte recruitment and activation have been implicated in the progression of cerebral ischemia-reperfusion (I/R) injury, but the roles of specific lymphocyte subpopulations and cytokines during stroke remain to be clarified. Here we demonstrate that the infiltration of T cells into the brain, as well as the cytokines interleukin-23 (IL-23) and IL-17, have pivotal roles in the evolution of brain infarction and accompanying neurological deficits. Blockade of T cell infiltration into the brain by the immunosuppressant FTY720 reduced I/R-induced brain damage. The expression of IL-23, which was derived mostly from infiltrated macrophages, increased on day 1 after I/R, whereas IL-17 levels were elevated after day 3, and this induction of IL-17 was dependent on IL-23. These data, together with analysis of mice genetically disrupted for IL-17 and IL-23, suggest that IL-23 functions in the immediate stage of I/R brain injury, whereas IL-17 has an important role in the delayed phase of I/R injury during which apoptotic neuronal death occurs in the penumbra. Intracellular cytokine staining revealed that gammadeltaT lymphocytes, but not CD4(+) helper T cells, were a major source of IL-17. Moreover, depletion of gammadeltaT lymphocytes ameliorated the I/R injury. We propose that T lymphocytes, including gammadeltaT lymphocytes, could be a therapeutic target for mitigating the inflammatory events that amplify the initial damage in cerebral ischemia.

Gfi1 negatively regulates T(h)17 differentiation by inhibiting RORgammat activity.

T(h) cells have long been divided into two subsets, T(h)1 and T(h)2; however, recently, T(h)17 and inducible regulatory T (iTreg) cells were identified as new T(h) cell subsets. Although T(h)1- and T(h)2-polarizing cytokines have been shown to suppress T(h)17 and iTreg development, transcriptional regulation of T(h)17 and iTreg differentiation by cytokines remains to be clarified. In this study, we found that expression of the growth factor independent 1 (Gfi1) gene, which has been implicated in T(h)2 development, was repressed in T(h)17 and iTreg cells compared with T(h)1 and T(h)2 lineages. Gfi1 expression was enhanced by the IFN-gamma/STAT1 and IL-4/STAT6 pathways, whereas it was repressed by the transforming growth factor-beta1 stimulation at the promoter level. Over-expression of Gfi1 strongly reduced IL-17A transcription in the EL4 T cell line, as well as in primary T cells. This was due to the blockade of recruitment of retinoid-related orphan receptor gammat to the IL-17A promoter. In contrast, IL-17A expression was significantly enhanced in Gfi1-deficient T cells under T(h)17-promoting differentiation conditions as compared with wild-type T cells. In contrast, the impacts of Gfi1 in iTregs were not as strong as in T(h)17 cells. Taken together, these data strongly suggest that Gfi1 is a negative regulator of T(h)17 differentiation, which represents a novel mechanism for the regulation of T(h)17 development by cytokines.

Sprouty4 deficiency potentiates Ras-independent angiogenic signals and tumor growth.

Sprouty proteins have been shown to negatively regulate a variety of receptor tyrosine kinase (RTK) signaling pathways and are considered to be tumor suppressor proteins. The pathophysiological functions of Sproutys in vivo remain to be investigated. In this study, we examined the physiological function of Sprouty4 as an angiogenic regulator, using Sprouty4 knockout (KO) mice and cells. We found that transplanted tumor cells grow much faster in Sprouty4 KO mice than in wild type (WT) mice, which we associate with enhanced neovascularization in the tumors transplanted into Sprouty4 KO mice. Moreover, vascular endothelial growth factor (VEGF)-A-induced angiogenesis and vascular permeability in vivo were enhanced in Sprouty4 KO mice compared with WT mice. Ex vivo angiogenesis, which we induced by VEGF-A, basic fibroblast growth factor (bFGF), and sphingosine-1-phosphate (S1P), was also enhanced in the aortas of Sprouty4 KO mice. We demonstrated that Sprouty4 suppresses Ras-independent VEGF-A and S1P signaling, while it does not affect Ras-dependent VEGF-C signaling. These data indicate that Sprouty4 selectively suppresses Ras-independent angiogenic factor signals and is an important negative regulator of pathophysiological angiogenesis.

The mTOR pathway is highly activated in diabetic nephropathy and rapamycin has a strong therapeutic potential.

Diabetic nephropathy (DN) associated with type 2 diabetes is the most common cause of end-stage renal disease (ESRD) and a serious health issue in the world. Currently, molecular basis for DN has not been established and only limited clinical treatments are effective in abating the progression to ESRD associated with DN. Here we found that diabetic db/db mice which lack the leptin receptor signaling can be used as a model of ESRD associated with DN. We demonstrated that p70S6-kinase was highly activated in mesangial cells in diabetic obese db/db mice. Furthermore, systemic administration of rapamycin, a specific and potent inhibitor of mTOR, markedly ameliorated pathological changes and renal dysfunctions. Moreover, rapamycin treatment shows a significant reduction in fat deposits and attenuates hyperinsulinemia with few side effects. These results indicate that mTOR activation plays a pivotal role in the development of ESRD and that rapamycin could be an effective therapeutic agent for DN.

A major lipid raft protein raftlin modulates T cell receptor signaling and enhances th17-mediated autoimmune responses.

The membrane microdomains known as lipid rafts have been shown to act as platforms for the initiation of various receptor signals. Through proteomic analysis, we have identified a novel protein termed Raftlin (raft-linking protein) as a major protein in lipid rafts. To determine the physiological and immunological functions of Raftlin in mammals, we generated Raftlin-deficient mice, as well as Raftlin-transgenic (Tg) mice. Although Raftlin was originally identified in B cells, we observe no severe abnormalities in the B cells of these mice, presumably due to a high expression of Raftlin-homologue (Raftlin-2). T cells, in contrast, expressed a substantial amount of Raftlin but no Raftlin-2. In Raftlin-deficient mice, T cell-dependent Ab production was reduced, and experimental autoimmune encephalomyelitis, a Th17-dependent autoimmune disease model, was ameliorated. In Raftlin-Tg mice, in contrast, Ab production was enhanced and experimental autoimmune encephalomyelitis was more severe. Cytokine production, especially that of IL-17, was reduced in Raftlin-deficient T cells, while it was enhanced in Raftlin-Tg T cells. We found that these changes were associated with the strength of the TCR-mediated signals. Importantly, localization of Lck protein in the lipid rafts was enhanced by Raftlin overexpression and reduced by Raftlin deficiency. These data indicate that Raftlin modulates TCR signals and is necessary for the fine-tuning of T cell-mediated immune responses.

A simple synthesis of four stereoisomers of roseoside and their inhibitory activity on leukotriene release from mice bone marrow-derived cultured mast cells.

Four stereoisomers of roseoside (vomifoliol glucosides) were synthesized using glucose as a chiral resolving reagent. The four synthetic stereoisomers exhibited inhibitory activity on leukotriene release from mouse bone marrow-derived cultured mast cells (BMCMC). The (6S)-isomers of roseoside were about twice as active as (6R)-isomers.

A novel subset of mouse NKT cells bearing the IL-17 receptor B responds to IL-25 and contributes to airway hyperreactivity.

Airway hypersensitive reaction (AHR) is an animal model for asthma, which is caused or enhanced by environmental factors such as allergen exposure. However, the precise mechanisms that drive AHR remain unclear. We identified a novel subset of natural killer T (NKT) cells that expresses the interleukin 17 receptor B (IL-17RB) for IL-25 (also known as IL-17E) and is essential for the induction of AHR. IL-17RB is preferentially expressed on a fraction of CD4(+) NKT cells but not on other splenic leukocyte populations tested. IL-17RB(+) CD4(+) NKT cells produce predominantly IL-13 and Th2 chemokines upon stimulation with IL-25 in vitro. IL-17RB(+) NKT cells were detected in the lung, and depletion of IL-17RB(+) NKT cells by IL-17RB-specific monoclonal antibodies or NKT cell-deficient Jalpha18(-/-) mice failed to develop IL-25-dependent AHR. Cell transfer of IL-17RB(+) but not IL-17RB(-) NKT cells into Jalpha18(-/-) mice also successfully reconstituted AHR induction. These results strongly suggest that IL-17RB(+) CD4(+) NKT cells play a crucial role in the pathogenesis of asthma.

RCAI-17, 22, 24-26, 29, 31, 34-36, 38-40, and 88, the analogs of KRN7000 with a sulfonamide linkage: their synthesis and bioactivity for mouse natural killer T cells to produce Th2-biased cytokines.

RCAI-17, 22, 24-26, 29, 31, 34-36, 38-40, and 88, the analogs of KRN7000 with a sulfonamide linkage instead of an amide bond, were synthesized to examine their bioactivity for mouse natural killer (NK) T cells. RCAI-17, 22, 24-26, 29, 31, 34-36, and 88 are the aromatic sulfonamide analogs, while RCAI-39 and 40 are the aliphatic ones. RCAI-38 is a C-galactoside analog of RCAI-26, which is the p-toluenesulfonamide analog of KRN7000. According to their bioassay, these sulfonamide analogs were shown to be the stimulants of mouse NKT cells to induce the production of Th2-biased cytokines in vitro, while RCAI-38 did not induce any cytokine production.

PDC-TREM, a plasmacytoid dendritic cell-specific receptor, is responsible for augmented production of type I interferon.

Type I interferons (IFNs) derived from plasmacytoid dendritic cells (PDCs) are critical for antiviral responses; however, the mechanisms underlying their production remain unclear. We have identified a receptor, PDC-TREM, which is associated with Plexin-A1 (PlxnA1) on the PDC cell surface and is preferentially expressed after TLR-stimulation. Limited TLR signals induced PDC-TREM expression but failed to induce IFN-alpha production. However, when coupled with Sema6D, a ligand for Plexin-A1, limited TLR-stimulation resulted in PDC-TREM-mediated DAP12-dependent phosphorylation of phosphoinositide 3-kinase (PI3K) and extracellular regulated kinase (Erk) 1/2 at 6-9 h, and IFN-alpha was produced. Inhibition of PDC-TREM expression by pdctrem-shRNA, blocking of PDC-TREM-binding with PlxnA1 by PDC-TREM mAb, and DAP12 deficiency all resulted in greatly reduced PDC-TREM-dependent activation of signaling molecules and IFN-alpha production. Thus, PDC-TREM is responsible for IFN-alpha production, whereas TLR signals are essential for PDC-TREM expression.

Methods for detection, isolation and culture of mouse and human invariant NKT cells.

This protocol describes methods to identify, purify and culture CD1d restricted invariant natural killer T (iNKT) cells from mouse tissue or human blood samples. The methods for identification and purification of iNKT cells are based on the interaction between iNKT cell receptor and its ligand. The iNKT cell receptor is composed of the invariant V alpha 14 J alpha 18/V beta 8.2 in mice or V alpha 24 J alpha 18/V beta 11 in humans and is expressed only on iNKT cells but not on conventional T cells. The iNKT cell antigen receptor in both species recognizes alpha-galactosylceramide (alpha-GalCer) presented by the MHC class I-like CD1d. Thus, alpha-GalCer-loaded CD1d dimer can be used for analysis and purification by fluorescence-activated cell sorting (FACS). Isolation of 1 x 10(6) purified iNKT cells from mouse thymus, spleen or liver requires 5-6 mice and takes 1-2 h for mononuclear cell preparation from mouse tissues, 1.5 h for enrichment by magnetic beads and 4 h for detection and purification of the iNKT cells by FACS. In the case of isolation of human peripheral blood mononuclear cells (PBMCs) from whole blood, it takes 2 h and requires 5 ml of blood to obtain 5 x 10(6) PBMCs, which contain 500-25,000 iNKT cells.

RCAI-8, 9, 18, 19, and 49-52, conformationally restricted analogues of KRN7000 with an azetidine or a pyrrolidine ring: Their synthesis and bioactivity for mouse natural killer T cells to produce cytokines.

Conformationally restricted analogues of KRN7000, an alpha-d-galactosyl ceramide, were synthesized to examine their bioactivity for mouse natural killer (NK) T cells to produce cytokines. RCAI-8, 9, 51, and 52 are the analogues with a pyrrolidine ring, and RCAI-18, 19, 49, and 50 are those with an azetidine ring. RCAI-18 was shown to be a potent inducer of cytokine production by mouse NKT cells, while RCAI-51 was a moderately active inducer.

Galectin-9 protects mice from the Shwartzman reaction by attracting prostaglandin E2-producing polymorphonuclear leukocytes.

Galectins play a crucial role in the modulation of innate and adaptive immunity. Here we show that galectin-9 (Gal-9) exhibits an anti-inflammatory role in LPS-induced inflammation. Intraperitoneal LPS injection enhances Gal-9 levels as well as promotes the production of pro-inflammatory cytokines, e.g., TNF-alpha, IFN-gamma and IL-12. We found that Gal-9 administration results in the protection of mice from the Shwartzman reaction, and Gal-9-deficient mice became susceptible to the Shwartzman reaction, thus implying the anti-inflammatory activity of Gal-9 against LPS-induced inflammation. Indeed, Gal-9 treatment together with LPS suppresses production of these pro-inflammatory cytokines, while it rather enhances than suppresses IL-4 and IL-10 production. We also found that LPS-induced elevation of TNF-alpha, IFN-gamma, and IL-12 does not occur in Gal-9 transgenic mice. Moreover, Gal-9 induces Gr-1(+) cell; probably polymorphonuclear leukocyte (PMN), as well as infiltration in to the peritoneal cavity, causing us to hypothesize PMNs are involved in Gal-9-mediated suppression. The fact that Gal-9 does not suppress LPS-induced TNF-alpha, IFN-gamma and IL-12 production in neutropenic mice, and that it does not protect those mice from the Shwartzman reaction, confirms the involvement of PMN in regulation. PMN attracted by Gal-9 produce PGE(2), which LPS-induced TNF-alpha production from the peritoneal macrophages is suppressed, while PMNs attracted by casein produce less PGE(2) and fail to suppress LPS-induced TNF-alpha production. Our data suggest that Gal-9 regulates LPS-induced inflammation and protects mice from the Shwartzman reaction by attracting PGE(2)-producing PMN.

Tyk2 signaling in host environment plays an important role in contraction of antigen-specific CD8+ T cells following a microbial infection.

Tyrosine kinase 2 (Tyk2), a member of JAK signal transducer family contributes to the signals triggered by IL-12 for IFN-gamma production. To elucidate potential roles of Tyk2 in generation and maintenance of Ag-specific CD8+ T cells, we followed the fate of OVA-specific CD8+ T cells in Tyk2-deficient (-/-) mice after infection with recombinant Listeria monocytogenes expressing OVA (rLM-OVA). Results showed that the numbers of OVA(257-264)/K(b) tetramer-positive CD8+ T cells in Tyk2(-/-) mice were almost the same as those in Tyk2(+/+) mice at the expansion phase on day 7 but were significantly larger in Tyk2(-/-) mice than those in Tyk2(+/+) mice at the contraction phase on day 10 and at the memory phase on day 60 after infection. The intracellular expression level of active caspase-3 was significantly decreased in the OVA-specific CD8+ T cells of Tyk2(-/-) mice on day 7 compared with those of Tyk2(+/+) mice. Adaptive transfer experiments revealed that Tyk2 signaling in other factors rather than CD8+ T cells played a regulatory role in CD8+ T cell contraction following infection. Administration of exogenous IFN-gamma from day 6 to day 9 restored the CD8+ T cell contraction in Tyk2(-/-) mice after infection with rLM-OVA. These results suggest that Tyk2 signaling for IFN-gamma production in host environment plays an important role in contraction of effector CD8+ T cells following a microbial infection.