Inositol phosphate kinase Vip1p interacts with histone chaperone Asf1p in Saccharomyces cerevisiae.

Histone eviction and deposition are critical steps in many nuclear processes. The histone H3/H4 chaperone Asf1p is highly conserved and is involved in DNA replication, DNA repair, and transcription. To identify the factors concerned with anti-silencing function 1 (ASF1), we purified Asf1p-associated factors from the yeast Saccharomyces cerevisiae by a GST pull-down experiment, and mass spectrometry analysis was performed. Several factors are specifically associated with Asf1p, including Vip1p. VIP1 is conserved from yeast to humans and encodes inositol hexakisphoshate and inositol heptakisphosphate kinase. Vip1p interacted with Asf1p as a dimer or in a complex with another protein(s). Deletion of VIP1 did not affect the interaction between Asf1p and other Asf1p-associated factors. An in vitro GST pull-down assay indicated a direct interaction between Asf1p and Vip1p, and the interaction between the two factors in vivo was detected by an immunoprecipitation experiment. Furthermore, genetic experiments revealed that VIP1 disruption increased sensitivity to 6-azauracil (6-AU), but not to DNA-damaging reagents in wild-type and ASF1-deleted strains. It is thought that 6-AU decreases nucleotide levels and reduces transcription elongation. These observations suggest that the association of Asf1p and Vip1p may be implicated in transcription elongation.

Pharmacological profile of the novel anti-inflammatory corticosteroid NS-126, a therapeutic agent for allergic rhinitis.

NS-126 (9-fluoro-11beta,17,21-trihydroxy-16alpha-methylpregna-1,4-diene-3,20-dione 21-cyclohexanecarboxylate 17-cyclopropanecarboxylate) is a novel, highly lipophilic anti-inflammatory corticosteroid. We compared NS-126 and the widely used intranasal corticosteroid fluticasone propionate (FP) in a guinea-pig model of allergic rhinitis and a rat model of airway eosinophilia. In the allergic rhinitis model, NS-126 and FP reduced sneezing and nasal obstruction to similar extents. In the airway eosinophilia model, both compounds inhibited the infiltration of eosinophils into the bronchoalveolar lavage fluid, but the effect of NS-126 was longer-lasting than that of FP. In vitro, NS-126 showed lower affinity than FP for the glucocorticoid receptor and was a weaker inhibitor of Th(2) cytokine and chemokine production and mast-cell secretory responses. We also investigated DX-17-CPC, a metabolite of NS-126 generated in nasal tissue by carboxylesterase-catalyzed hydrolysis at the 17-position. DX-17-CPC showed greater affinity than NS-126 for the glucocorticoid receptor and was a stronger inhibitor of Th(2) cytokine and chemokine production and mast-cell secretory responses. The long duration of the anti-allergic effects of NS-126 may be explained by its high lipophilicity, while the strength of its anti-allergic effects may be explained by the generation of the active metabolite DX-17-CPC. NS-126 is a long-acting intranasal corticosteroid and a promising therapeutic agent for allergic rhinitis.

Synthesis and biological evaluation of novel phthalazinone derivatives as topically active phosphodiesterase 4 inhibitors.

Inhibitors of phosphodiesterase 4 (PDE4) are an important class of anti-inflammatory drug that act by inhibiting the production of proinflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha). We have synthesized and evaluated a series of 2-substituted phthalazinone derivatives as PDE4 inhibitors. Structure-activity relationship studies led to the identification of benzylamine-substituted phthalazinones as potent PDE4 inhibitors that also suppressed TNF-alpha production by whole rat blood cells. The most potent of these, when topically administered, were effective in a mouse model of dermatitis.

Irsogladine maleate suppresses indomethacin-induced elevation of proinflammatory cytokines and gastric injury in rats.

AIM: To investigate the mucosal protective effect and the mechanisms of action of the anti-ulcer drug irsogladine maleate in gastric injury induced by indomethacin in rats. METHODS: Gastric mucosal injury was induced in male Hos:Donryu rats by oral administration of indomethacin at a dose of 48 mg/kg. One hour before indomethacin treatment, animals were orally pretreated with irsogladine maleate at doses of 1 mg/kg, 3 mg/kg or 10 mg/kg. Four hours after indomethacin administration, the animals were sacrificed and their stomachs were rapidly removed and processed for the evaluation of gastric mucosal damage and the determination of the concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-8 and myeloperoxidase (MPO) in mucosal tissues. RESULTS: Linear hemorrhagic mucosal lesions were observed primarily in the glandular stomach 4 h after oral administration of indomethacin. Pretreatment with irsogladine maleate markedly reduced the number and severity of these lesions in a dose-dependent manner. The mucosal concentrations of proinflammatory cytokines (TNF-alpha, IL-1beta, and IL-8) and MPO, which indicates the degree of mucosal infiltration by neutrophils, increased concomitantly with the occurrence of gastric injury in the indomethacin-treated rats. Pretreatment with irsogladine maleate significantly decreased the levels of these inflammatory factors in gastric tissue elicited by indomethacin. CONCLUSION: The mucosal protective effects afforded by irsogladine maleate on gastric injury induced by indomethacin are mediated by inhibition of mucosal proinflammatory cytokine production and neutrophil infiltration, leading to suppression of mucosal inflammation and subsequent tissue destruction.