Fingolimod (FTY720), sphingosine 1-phosphate receptor modulator, shows superior efficacy as compared with interferon-ß in mouse experimental autoimmune encephalomyelitis.

Fingolimod (FTY720), a sphingosine 1-phosphate (S1P) receptor modulator, inhibits S1P-dependent lymphocyte egress from secondary lymphoid organs and is highly effective in experimental autoimmune encephalomyelitis (EAE) in mice. In this study, we directly compared the therapeutic effects of FTY720 and recombinant mouse interferon (rm-IFN)-ß on relapse and progression of EAE in mice. When FTY720 at oral dose of 0.03 to 1 mg/kg was administered daily after establishment of EAE induced by myelin proteolipid protein (PLP) in SJL/J mice, relapse of EAE was significantly inhibited during administration period. Subcutaneous injection of rm-IFN-ß (10,000 IU/mouse) also inhibited the relapse of EAE at early period; however EAE was relapsed in all the mice within administration period. Therapeutic administration of FTY720 (0.03 to 1 mg/kg) significantly improved the symptoms of chronic EAE induced by myelin oligodendrocyte glycoprotein in C57BL/6 mice whereas rm-IFN-ß (10,000 IU/mouse) showed no clear effect. These results indicate that FTY720 is more efficacious in mouse EAE as compared with rm-IFN-ß. FTY720 markedly reduced the frequency of PLP-specific Th17 and Th1 cells in the spinal cord of EAE mice. On the contrary, FTY720 increased the frequency of PLP-specific Th17 and Th1 cells in the inguinal lymph nodes, suggesting inhibition of egress of myelin antigen-specific Th cells from draining lymph nodes. From these results, the ameliorating effects of FTY720 on EAE are likely due to reduction of infiltration of myelin antigen-specific Th17 and Th1 cells into the central nervous system.

Inhibition of tumor progression locus 2 protein kinase decreases lipopolysaccharide-induced tumor necrosis factor alpha production due to the inhibition of the tip-associated protein induction in RAW264.7 cells.

The activation of mitogen-activated protein kinases (MAPKs) is critically involved in inflammatory events through mediation of the production of various inflammatory cytokines. The Tpl2 (tumor progression locus 2)-MEK (MAPK/ERK kinase)-ERK (extracellular signal-regulated kinase) signaling pathway plays an essential role in the production of tumor necrosis factor alpha (TNFalpha) in macrophages stimulated with lipopolysaccharide (LPS). Here, we studied the molecular mechanisms of Tpl2-mediated TNFalpha production using a potent Tpl2 kinase inhibitor, 1,7-naphtyridine-3-carbonitrile, and LPS-stimulated RAW264.7 cells. This inhibitor was effective in suppressing the in vitro Tpl2 kinase activity, and caused a significant reduction in TNFalpha production via specific suppression of the phosphorylation of MEK and ERK but not that of p38 and c-Jun N-terminal kinase (JNK). A p38 inhibitor, SB203580, also inhibited the TNFalpha production dose-dependently. Although the TNFalpha mRNA level was not altered by either inhibitor, the Tpl2 inhibitor increased the nuclear TNFalpha mRNA level, while decreasing that in the cytoplasm. Tip-associated protein (TAP), a key molecule in the nucleocytoplasmic transport of TNFalpha mRNA, was up-regulated by LPS, but this increase was impaired by the Tpl2 inhibitor. In all cases, SB203580 was without effect in the presence of LPS. These results suggest that the LPS-induced TNFalpha production via the Tpl2-MEK-ERK signaling pathway is regulated by changing the TAP level at the nucleocytoplasmic transport level. These results improve understanding of TNFalpha regulatory mechanisms and might provide a new therapeutic strategy against inflammatory diseases.

[Targeting therapy for inflammatory diseases by anti-TNFalpha biologics].

TNFalpha (tumor necrosis factor-alpha) plays a critical role in the pathogenesis of inflammatory diseases including rheumatoid arthritis and Crohn's disease. Infliximab is a monoclonal antibody that recognizes human TNFalpha. Clinical trials have been persuasive that infliximab is effective and far superior to the conventional drug therapy in various inflammatory diseases. Combination of infliximab plus methotrexate is effective in patients with active rheumatoid arthritis who have not responded adequately to traditional disease-modifying anti-rheumatic drugs, and has produced significant improvement in clinical, radiographic, and functional outcomes. Infliximab is also an important treatment option in patients with active Crohn's disease who have not responded to conventional therapy and in those with this disease who have fistulae. Moreover, infliximab treatment has resulted in effective suppression of ankylosing spondylitis, psoriasis and ocular inflammation in patients with refractory uveoretinitis due to Behçet's disease. Thus, biologics targeting TNFalpha have revolutionized the therapy of inflammatory diseases. Here, the current status of clinical application of anti-TNFalpha biologics is reviewed by describing the clinical outcome of infliximab and future prospects of biologics are discussed.

Highly sensitive cell-based assay system to monitor the sialyl Lewis X biosynthesis mediated by alpha1-3 fucosyltransferase-VII.

The sialyl Lewis X (sLe(x)) determinant on leukocytes serves as a ligand for selectin family cell adhesion molecules, and selectin-carbohydrate interaction is considered to play an important role in the process of leukocyte extravasation during inflammation. Among several alpha1-3 fucosyltransferases (FucTs), FucT-VII plays a critical role in the biosynthesis of sLe(x)-epitopes. Therefore, small molecules specifically designed to inhibit the FucT-VII enzyme may have potential as anti-inflammatory agents. Here, we have developed a versatile cell-based assay system to monitor sLe(x) biosynthesis using the GeneSwitch System. This system is a mifepristone (MFP)-inducible mammalian expression system, and human transfectant T lymphoblasts expressed the mRNA of FucT-VII and the sLe(x)-epitopes on the cell surface in a time-dependent manner in the presence of MFP, with very low background transcription. Furthermore, when the transfectants were treated with the FucT-VII inhibitor panosialin, sLe(x) expression on the induced cells was inhibited dose dependently without alteration at the mRNA level of FucT-VII. These results suggest that the FucT-VII may be a major regulator of the biosynthesis of the sLe(x)-epitopes on T lymphoblasts, and this cell-based assay may be utilized for a screening system of FucT-VII inhibitors.

Development of a sensitive separation and quantification method for sialyl Lewis X and Lewis X involving anion-exchange chromatography: biochemical characterization of alpha1-3 fucosyltransferase-VII.

The biosynthesis of the carbohydrate antigen sialyl Lewis X (sLe(x)) in human leukocytes is mediated by alpha1-3 fucosyltransferase-VII (FucT-VII), which catalyzes the transfer of fucose from GDP-beta-fucose to the 3-OH of alpha2-3 sialyl N-acetyllactosamine (SA-LN). We developed a simple method for quantitating the reaction product of FucT-VII involving Anion-Exchange Chromatography (AEC). The AEC assay involved the separation of a radio-labeled acceptor from the unreacted nucleotide sugars with 0-0.5 M NH(4)OAc (pH9.0) on QAE-Toyopearl 550C. Furthermore, this assay enabled the separation of the fucosylated products of sialylated and non-sialylated oligosaccharides with this column. Analysis of the FucT-VI reaction mixture showed that Lewis X (Le(x)) was eluted in the flow-through fraction and sLe(x) was eluted with 0.1 M NH(4)OAc, and these products were clearly separated from the fraction of unreacted GDP-[(3)H]fucose. Therefore, this method could be a powerful tool for the characterization of recombinant FucT-VII and for establishing a high-throughput screening system for FucT-VII inhibitors. Beside FucT-VII, this method will be applicable to the assaying of many different glycosyltransferases, including sialyltransferases and glucosaminyltransferases, which are reactive to alpha2-3 SA-LN or N-acetyllactosamine sequences.

[Pharmacological profile of anti-human TNF alpha monoclonal antibody, infliximab (Remicade)].

TNF alpha (tumor necrosis factor-alpha) plays an important role in the pathogenesis of inflammatory diseases including Crohn's disease and rheumatoid arthritis. Infliximab (Remicade) is a chimeric monoclonal antibody that recognizes human TNF alpha. Clinical trials trials have been persuasive that infliximab is effective in both Crohn's disease and rheumatoid arthritis. Infliximab is an important treatment option in patients with active Crohn's disease who have not responded to conventional therapy and in patients with Crohn's disease who have fistulae. Moreover, infliximab plus methotrexate is effective in patients with active rheumatoid arthritis who have not responded adequately to traditional disease-modifying anti-rheumatic drugs, in terms of reducing symptoms and signs, inhibiting the progression of structural damage and improving physical function.

TAK1-TAB1 fusion protein: a novel constitutively active mitogen-activated protein kinase kinase kinase that stimulates AP-1 and NF-kappaB signaling pathways.

TAK1 mitogen-activated protein kinase kinase kinase (MAP3K) is activated by its specific activator, TAK1-binding protein 1 (TAB1). A constitutively active TAK1 mutant has not yet been generated due to the indispensable requirement of TAB1 for TAK1 kinase activity. In this study, we generated a novel constitutively active TAK1 by fusing its kinase domain to the minimal TAK1-activation domain of TAB1. Co-immunoprecipitation assay demonstrated that these domains interacted intra-molecularly. The TAK1-TAB1 fusion protein showed a significant MAP3K activity in vitro and activated c-Jun N-terminal kinase/p38 MAPKs and IkappaB kinase in vivo, which was followed by increased production of interleukin-6. These results indicate that the fusion protein is useful for characterizing the physiological roles of the TAK1-TAB1 complex.