A potent neuromedin U receptor 2-selective alkylated peptide

Neuromedin U (NMU) mediates various physiological functions via NMUR1 and NMUR2 receptors. NMUR2 has been considered a promising treatment option for diabetes and obesity. Although NMU-8, a shorter peptide, has potent agonist activity for both receptors, it is metabolically unstable. Therefore, NMU-8 analogs modified with long-chain alkyl moieties via a linker were synthesized. An octadecanoyl analog (17) with amino acid substitutions [αMePhe¹⁹, Nle²¹, and Arg(Me)²⁴] and a linker [Tra-γGlu-PEG(2)] dramatically increased NMUR2 selectivity, with retention of high agonist activity. Subcutaneous administration of 17 induced anorectic activity in C57BL/6J mice. Owing to its high metabolic stability, 17 would be useful in clarifying the physiological role and therapeutic application of NMU.     

Herquline A,produced by Penicillium herquei FKI-7215, exhibits anti-influenza virus properties

In the course of screening for new anti-influenza virus antibiotics, we isolated herquline A from a culture broth of the fungus, Penicillium herquei FKI-7215. Herquline A inhibited replication of influenza virus A/PR/8/34 strain in a dose-dependent manner without exhibiting cytotoxicity against several human cell lines. It did not inhibit the viral neuraminidase.     

Acrolein-detoxifying isozymes of glutathione transferase in plants

Main conclusion

Acrolein is a lipid-derived highly reactive aldehyde, mediating oxidative signal and damage in plants. We found acrolein-scavenging glutathione transferase activity in plants and purified a low K _M isozyme from spinach.

Various environmental stressors on plants cause the generation of acrolein, a highly toxic aldehyde produced from lipid peroxides, via the promotion of the formation of reactive oxygen species, which oxidize membrane lipids. In mammals, acrolein is scavenged by glutathione transferase (GST; EC 2.5.1.18) isozymes of Alpha, Pi, and Mu classes, but plants lack these GST classes. We detected the acrolein-scavenging GST activity in four species of plants, and purified an isozyme showing this activity from spinach (Spinacia oleracea L.) leaves. The isozyme (GST-Acr), obtained after an affinity chromatography and two ion exchange chromatography steps, showed the K _M value for acrolein 93 μM, the smallest value known for acrolein-detoxifying enzymes in plants. Peptide sequence homology search revealed that GST-Acr belongs to the GST Tau, a plant-specific class. The Arabidopsis thaliana GST Tau19, which has the closest sequence similar to spinach GST-Acr, also showed a high catalytic efficiency for acrolein. These results suggest that GST plays as a scavenger for acrolein in plants.

     

Seasonal variation of phlorotannin in sargassacean species from the coast of the Sea of Japan

Variations in phlorotannin concentrations among the developmental stages of brown algae have been reported; however, the phlorotannin concentration plasticity associated with fluctuations in environmental factors make it difficult to determine the essential ontogenetic variation. The phlorotannin concentrations in five perennial sargassacean species where newly sprouted branches appear in summer and become fertile the following spring were examined every month during a year; and correlation with the developmental or seasonal environmental factors was determined. Although the phlorotannin fluctuated greatly throughout the year, the fluctuation patterns were relatively similar among the five species: phlorotannin showed a peak during July and August; gradually decreased in the winter; and increased in April. Performing a multiple regression analysis, the phlorotannin concentration did not correlate with thallus size in all species; and phlorotannin amounts were significantly affected by ambient abiotic factors in some species. The phlorotannin contents in newly sprouted branches were always higher than those in the long main branches during all seasons. When the phlorotannin contents were determined monthly for S. fulvellum (Turner) C. Agardh where the thalli were cultured from embryos in outdoor tanks, the phlorotannin concentrations were 3–4% of the dry matter (DM) in the juveniles and decreased to less than 1% of the DM in thalli >7.5 cm in length. However, the phlorotannin in these cultured thalli suddenly increased to 5.3% DM after being transplanted to the inshore coast; and then the concentration gradually decreased. The data show higher phlorotannin concentrations in younger sargassacean algae thalli and fluctuation of the phlorotannin amounts with extrinsic environmental factors.     

Inhibition of D-serine accumulation in the Xenopus oocyte by expression of the rat ortholog of human 3'-phosphoadenosine 5'-phosphosulfate transporter gene isolated from the neocortex as D-serine modulator-1

D-serine in mammalian brains has been suggested to be an endogenous co-agonist of the NMDA-type glutamate receptor. We have explored the molecules regulating D-serine uptake and release from the rat neocortex cDNA library using a Xenopus oocyte expression system, and isolated a cDNA clone designated as dsm-1 (D-serine modulator-1) encoding a protein that reduces the accumulation of D-serine to the oocyte. dsm-1 is the rat orthologue of the human 3'-phosphoadenosine 5'-phosphosulfate transporter 1 (PAPST1) gene. The hydropathy analysis of the deduced amino acid sequence of the Dsm-1 protein predicts the 10 transmembrane domains with a long hydrophobic stretch in the C-terminal like some amino acid transporters. The dsm-1 mRNA is predominantly expressed in the forebrain areas that are enriched with D-serine and NMDA receptors, and in the liver. The transient expression of dsm-1 in COS-7 cells demonstrates a partially Golgi apparatus-related punctuate distribution throughout the cytoplasm with a concentration near the nucleus. dsm-1-expressing oocytes diminishes the sodium-dependent and -independent accumulation of D-serine and the basal levels of the intrinsic D-serine and increases the rate of release of the pre-loaded D-serine. These findings indicate that dsm-1 may, at least in part, be involved in the D-serine translocation across the vesicular or plasma membranes in the brain, and thereby control the extra- and intracellular contents of D-serine.     

Development of dry powder inhalation system of novel vasoactive intestinal peptide (VIP) analogue for pulmonary administration

Vasoactive intestinal peptide (VIP) exerts a relaxing action on tracheal smooth muscle which is mediated through interaction with VIP receptors. The deficiency of VIP in the airways has been implicated in the pathogenesis of asthma. Thus, the administration of VIP may be useful for the therapy of pulmonary diseases. However, the therapeutic application of VIP is largely limited by its rapid degradation in addition to the systemic adverse effects due to the wide distribution of VIP receptors. To overcome these problems, we succeeded to synthesize a novel VIP derivative of VIP, [R15, 20, 21, L17]-VIP-GRR (IK312532), and to prepare its dry powder for the topical administration to the lung. The physicochemical properties of dry powder were evaluated by laser diffraction and cascade impactor. The laser diffraction analysis indicated that the carrier and fine particles had median diameter of 65.6 and 4.5 microm, respectively, and the air flow at the pressure of 0.15 MPa or higher resulted in the high dispersion and significant separation of fine particle containing peptide from the carrier molecule. The cascade impactor analysis clearly showed the high emission of dry powder from capsule and the deposition of peptide on stages 3 of the cascade impactor. The intratracheal administration of dry powder inhaler (DPI) of VIP or IK312532 brought about a significant decrease of maximal number of binding sites (Bmax) for [125I]VIP in anterior and posterior lobes of rat right lung, suggesting a significant occupancy of lung VIP receptors. This effect by IK312532-DPI compared with VIP-DPI lasted for a longer period. Thus, IK312532-DPI may be a pharmacologically useful drug delivery system for the VIP therapy of pulmonary diseases such as asthma.     

New lead compounds for brassinosteroid biosynthesis inhibitors

The first brassinosteroid biosynthesis inhibitor is reported. Among newly synthesized triazole derivatives, 4-(4-chlorophenyl)-2-phenyl-3-(1,2,4-triazoyl)butan-2-ol (6) was found to inhibit the growth of cress seedlings, and this inhibition was recovered by the treatment of brassinolide, suggesting that compound 6 primarily inhibits brassinosteroid biosynthesis.     

A simple set-and-mix assay for screening of protein kinase inhibitors in cell lysates

Here we developed a simple set-and-mix assay to perform high-throughput screening of protein kinase A (PKA) inhibitors from the LOPAC 1280 compound library. This assay is based on the color change of gold nanoparticles on aggregation induced by a cationic substrate peptide as coagulant. In spite of the simplicity of this assay system, this assay can be applied to drug screening based on cellular kinases. We successfully found several highly active inhibitors, including compounds that have not been reported before.