Simultaneous detection of histamine release and lactate production in rat mast cells induced by compound 48/80 using H NMR

¹H NMR spectroscopy was used to evaluate histamine release and lactate production in intact mast cells isolated from rats. The resonance lines of the aromatic histamine protons in mast cells, detected by the selective spin-excitation technique, were broader and located in a lower magnetic field than those in free histamine solution. When exocytosis of mast-cell granules was induced by compound 48/80, free histamine appeared, with a corresponding decrease in the amount of histamine in the mast cells; the lactate signal was also detected in the spectrum. On the addition of compound 48/80, there was a further release of histamine from mast cells, accompanied by further production of lactate. This result indicates that the mechanisms which induce the exocytosis of granules, and/or the events folowing exocytosis, activate glycolysis.     

Phospholipid Acyl-hydrolases from a Mold,Corticium centrifugum

The activities of phospholipids acyl-hydrolases in an enzyme preparation from a mold, Corticium centrifugum, were examined. Lecithin acyl-hydrolase had an optimal pH at 3.5. The reaction proceeded beyond the range of 50%. Sigmoidal curves observed suggested the presence of lysophospholipase in the preparation. The latter enzyme activity was found to be seven times as strong as the former at the same pH. Fractionation by DEAE-Sephadex chromatography and analysis of the reaction products demonstrated that the main component of lecithin acyl-hydrolase was phospholipase B, which hydrolyzed both of fatty acyl ester groups of lecithin. This activity was found to be present as a separate enzyme from most of lysophospholipase.     

Antiobesity and emetic effects of a short-length peptide YY analog and its PEGylated and alkylated derivatives

Neuropeptide Y2 receptor (Y2R) agonism is an important anorectic signal and a target of antiobesity drug discovery. Recently, we synthesized a short-length Y2R agonist, PYY-1119 (4-imidazolecarbonyl-[d-Hyp²⁴,Iva²⁵,Pya(4)²⁶,Cha^27,36,γMeLeu²⁸,Lys³⁰,Aib³¹]PYY(23–36), 1) as an antiobesity drug candidate. Compound 1 induced marked body weight loss in diet-induced obese (DIO) mice; however, 1 also induced severe vomiting in dogs at a lower dose than the minimum effective dose administered to DIO mice. The rapid absorption of 1 after subcutaneous administration caused the severe vomiting. Polyethylene glycol (PEG)- and alkyl-modified derivatives of 1 were synthesized to develop Y2R agonists with improved pharmacokinetic profiles, i.e., lower maximum plasma concentration (C_max) and longer time at maximum concentration (T_max). Compounds 5 and 10, modified with 20?kDa PEG at the N-terminus and eicosanedioic acid at the Lys³⁰ side chain of 1, respectively, showed high Y2R binding affinity and induced significant body weight reduction upon once-daily administration to DIO mice. Compounds 5 and 10, with their relatively low C_max and long T_max, partially attenuated emesis in dogs compared with 1. These results indicate that optimization of pharmacokinetic properties of Y2R agonists is an effective strategy to alleviate emesis induced by Y2R agonism.     

Discovery of orally efficacious RORγt inverse agonists. Part 2: Design,synthesis, and biological evaluation of novel tetrahydroisoquinoline derivatives

A series of tetrahydroisoquinoline derivatives were designed, synthesized, and evaluated for their potential as novel orally efficacious retinoic acid receptor-related orphan receptor-gamma t (RORγt) inverse agonists for the treatment of Th17-driven autoimmune diseases. We carried out cyclization of the phenylglycinamide core by structure-based drug design and successfully identified a tetrahydroisoquinoline carboxylic acid derivative 14 with good biochemical binding and cellular reporter activity. Interestingly, the combination of a carboxylic acid tether and a central fused bicyclic ring was crucial for optimizing PK properties, and the compound 14 showed significantly improved PK profile. Successive optimization of the carboxylate tether led to the discovery of compound 15 with increased inverse agonistic activity and an excellent PK profile. Oral treatment of mice with compound 15 robustly and dose-dependently inhibited IL-17A production in an IL23-induced gene expression assay.     

Discovery of novel serine palmitoyltransferase inhibitors as cancer therapeutic agents

We pursued serine palmitoyltransferase (SPT) inhibitors as novel cancer therapeutic agents based on a correlation between SPT inhibition and growth suppression of cancer cells. High-throughput screening and medicinal chemistry efforts led to the identification of structurally diverse SPT inhibitors 4 and 5. Both compounds potently inhibited SPT enzyme and decreased intracellular ceramide content. In addition, they suppressed cell growth of human lung adenocarcinoma HCC4006 and acute promyelocytic leukemia PL-21, and displayed good pharmacokinetic profiles. Reduction of 3-ketodihydrosphingosine, the direct downstream product of SPT, was confirmed under in vivo settings after oral administration of compounds 4 and 5. Their anti-tumor efficacy was observed in a PL-21 xenograft mouse model. These results suggested that SPT inhibitors might have potential to be effective cancer therapeutics.     

Effects of Dietary Supplementation with Fish Scales-Derived Collagen Peptides on Skin Parameters and Condition: A Randomized,Placebo-Controlled,Double-Blind Study

Fish scales-derived collagen peptides (CPs) are characterized by their specific amino acid composition with a high concentration of glycine, proline and hydroxyproline. These amino acids have been known to exert beneficial effects on human skin. The aim of the present study was to examine the effects of collagen peptides obtained from fish scales on changes in periorbital wrinkles, facial skin hydration, and skin elasticity in healthy women aged 30–60 years. In the present randomized, placebo-controlled, double-blind trial, 71 subjects consumed a 20 mL beverage containing 3000 mg of CPs or placebo once per day over 12 weeks. Significant decreases in periorbital wrinkles (p?<?0.05) were observed in the treatment group after 12 weeks of CPs ingestion compared to the control group. This study also demonstrated a consistent trend of enhanced facial skin moisture (p?<?0.001) and skin elasticity (p?<?0.001) by dietary intake of CPs without any side effects or adverse events. These findings indicate that fish-derived CPs hold great promise as a natural supplement with cutaneous anti-aging properties.