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Signal transduction through the p38 mitogen-activated protein (MAP) kinase pathway is central to the transcriptional and translational control of cytokine and inflammatory mediator production. p38 MAP kinase inhibition hence constitutes a promising therapeutic strategy for treatment of chronic inflammatory diseases, based upon its potential to inhibit key pathways driving the inflammatory and destructive processes in these debilitating diseases. The present study describes the pharmacological properties of the Nphenyl pyridinone p38 MAP kinase inhibitor benzamide [3-[3-bromo-4-[(2,4-PH-797804 is an ATP-competitive, readily reversible inhibitor of the ␣ isoform of human p38 MAP kinase, exhibiting a K i ϭ 5.8 nM. In human monocyte and synovial fibroblast cell systems, PH-797804 blocks inflammation-induced production of cytokines and proinflammatory mediators, such as prostaglandin E 2 , at concentrations that parallel inhibition of cell-associated p38 MAP kinase. After oral dosing, PH-797804 effectively inhibits acute inflammatory responses induced by systemically administered endotoxin in both rat and cynomolgus monkeys. Furthermore, PH-797804 demonstrates robust anti-inflammatory activity in chronic disease models, significantly reducing both joint inflammation and associated bone loss in streptococcal cell wall-induced arthritis in rats and mouse collagen-induced arthritis. Finally, PH-797804 reduced tumor necrosis factor-␣ and interleukin-6 production in clinical studies after endotoxin administration in a dose-dependent manner, paralleling inhibition of the target enzyme. Low-nanomolar biochemical enzyme inhibition potency correlated with p38 MAP kinase inhibition in human cells and in vivo studies. In addition, a direct correspondence between p38 MAP kinase inhibition and antiinflammatory activity was observed with PH-797804, thus providing confidence in dose projections for further human studies in chronic inflammatory disease.Rheumatoid arthritis (RA) is an aggressive autoimmune disease involving complex interactions among T cells, macrophages, synoviocytes, and other immune cells (Firestein, 2003). Analysis of synovial fluid and tissue from RA patients implicated key cytokines, including TNF-␣, IL-1␤, and IL-6 in the pathogenesis of the disease (Firestein et al., 1990). Further studies shed light on the complex networks within which these cytokines function and the delicate balance between a pro-or an anti-inflammatory outcome (McInnes and ABBREVIATIONS: RA, rheumatoid arthritis; TNF, tumor necrosis factor; IL, interleukin; COX, cyclooxygenase; MAP, mitogen-activated protein; ERK, extracellular signal-regulated kinase; JNK, c-Jun NH 2 -terminal kinase; benzamide,methoxy]-6-methyl-2-oxo-1(2H)-pyridinyl]-N,4-dimethyl-, (Ϫ)-(9CI); SCW, streptococcal cell wall; LPS, lipopolysaccharide; MKK, mitogen-activated protein kinase kinase; EGFRP, epidermal growth factor receptor peptide; GST, glutathione transferase; RASF, rheumatoid arthritis synovial fibroblast(s); MK-2, mitogen-activated protein kinase-act...

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SD0006 is a diarylpyrazole that was prepared as an inhibitor of p38 kinase-α (p38α). In vitro, SD0006 was selective for p38α kinase over 50 other kinases screened (including p38γ and p38δ with modest selectivity over p38β). Crystal structures with p38α show binding at the ATP site with additional residue interactions outside the ATP pocket unique to p38α that can confer advantages over other ATP competitive inhibitors. Direct correlation between inhibition of p38α activity and that of lipopolysaccharide-stimulated TNFα release was established in cellular models and in vivo, including a phase 1 clinical trial. Potency (IC₅₀) for inhibiting tumor necrosis factor-α (TNFα) release, in vitro and in vivo, was <200 nmol/l. In vivo, SD0006 was effective in the rat streptococcal-cell-wall-induced arthritis model, with dramatic protective effects on paw joint integrity and bone density as shown by radiographic analysis. In the murine collagen-induced arthritis model, equivalence was demonstrated to anti-TNFα treatment. SD0006 also demonstrated good oral anti-inflammatory efficacy with excellent cross-species correlation between the rat, cynomolgus monkey, and human. SD0006 suppressed expression of multiple proinflammatory proteins at both the transcriptional and translational levels. These properties suggest SD0006 could provide broader therapeutic efficacy than cytokine-targeted monotherapeutics.

Serine:glyoxylate aminotransferase, a marker enzyme for leaf peroxisomes, has been purified to homogeneity from cucumber cotyledons (Cucamis sativus cv Improved Long Green). The isolation procedure involved precipitation with polyethyleneimine, a two-step ammonium sulfate fractionation (35 to 45%), gel filtration on Ultrogel AcA 34, and ion exchange chromatography on diethylaminoethyl-cellulose, first in the presence of pyridoxal-5-phosphate, and then in its absence. The enzyme was purified approximately 690-fold to a final specific activity of 34.4 units per milligram. Electrophoresis of the purified enzyme on sodium dodecyl sulfate-polyacrylamide gels revealed two polypeptide bands with apparent molecular weights of approximately 47,000 and 45,000. Both polypeptides coeluted with enzyme activity under all chromatographic conditions investigated, both were localized to the peroxisome, and both accumulated in cotyledons as enzyme activity increased during development. The two polypeptides appear not to be structurally related, since they showed little immunological cross-reactivity and gave rise to different peptide fragments when subjected to partial proteolytic digestion. Antiserum raised against either the denatured enzyme or the 45,000-dalton polypeptide did not react with any other polypeptides present in a crude cotyledonary homogenate. The purified enzyme also had alanine:glyoxylate aminotransferase activity, but was about twice as active with serine as the amino donor.In cucurbits and related plant species with fat-storing cotyledons, the cotyledons serve as the site of lipid mobilization during early germination, then emerge above ground and become photosynthetic (2). The microbodies present at early stages (glyoxysomes) play a central role in fat mobilization, whereas those present after the onset of photosynthesis (peroxisomes) are involved in the glycolate pathway of photorespiration (2,28,29). The decrease in glyoxysomal enzyme activities usually occurs concomitantly with the increase in peroxisomal activities in the greening cotyledon (1,12,19,29). Much interest has focused on this changeover in microbody function (2,4,7,23,29), but the mechanism is still unresolved.