Suppression of Mast Cell Activation by GPR35: GPR35 Is a Primary Target of Disodium Cromoglycate.

Mast cell stabilizers, including disodium cromoglycate (DSCG), were found to have potential as the agonists of an orphan G protein-coupled receptor, GPR35, although it remains to be determined whether GPR35 is expressed in mast cells and involved in suppression of mast cell degranulation. Our purpose in this study is to verify the expression of GPR35 in mast cells and to clarify how GPR35 modulates the degranulation. We explored the roles of GPR35 using an expression system, a mast cell line constitutively expressing rat GPR35, peritoneal mast cells, and bone marrow-derived cultured mast cells. Immediate allergic responses were assessed using the IgE-mediated passive cutaneous anaphylaxis (PCA) model. Various known GPR35 agonists, including DSCG and newly designed compounds, suppressed IgE-mediated degranulation. GPR35 was expressed in mature mast cells but not in immature bone marrow-derived cultured mast cells and the rat mast cell line. Degranulation induced by antigens was significantly downmodulated in the mast cell line stably expressing GPR35. A GPR35 agonist, zaprinast, induced a transient activation of RhoA and a transient decrease in the amount of filamentous actin. GPR35 agonists suppressed the PCA responses in the wild-type mice but not in the GPR35-/- mice. These findings suggest that GPR35 should prevent mast cells from undergoing degranulation induced by IgE-mediated antigen stimulation and be the primary target of mast cell stabilizers. SIGNIFICANCE STATEMENT: The agonists of an orphan G protein-coupled receptor, GPR35, including disodium cromoglycate, were found to suppress degranulation of rat and mouse mature mast cells, and their antiallergic effects were abrogated in the GPR35-/- mice, indicating that the primary target of mast cell stabilizers should be GPR35.

Total Synthesis of Caldorazole, a Potent Mitochondrial Respiratory Chain Inhibitor without Chiral Centers.

Caldorazole (1) is a novel polyketide that was isolated from a marine cyanobacterium in 2022. It is a unique natural product that exhibits potent inhibitory activity against mitochondrial respiratory chain complex I despite having no chiral centers. To establish a method for obtaining caldorazole without relying on biological resources and for constructing a useful synthetic route for studies of its structure-activity relationship, we achieved the first total synthesis of caldorazole using a convergent synthetic route.

Synthesis and Evaluation of DHMEQ Derivatives with Tertiary Hydroxyl Group Instead of Secondary Hydroxyl Group.

Newly synthesized dehydroxymethyl epoxyquinomycin (DHMEQ) derivatives 6-9, which contain a tertiary hydroxyl group instead of the original secondary hydroxyl group, showed improved solubility in alcohol while maintaining their inhibitory activity against nitric oxide (NO) production, which is used as an indicator of nuclear factor-kappa B (NF-κB) inhibitory activity. We also synthesized a derivative 5 having a cyclopropane ring and a tertiary hydroxyl group and examined its inhibitory activity against NO production. Although it reacted with a nucleophile in a flask, it did not inhibit NO production. The change from a secondary hydroxyl group to a tertiary hydroxyl group contributed to improve the solubility of the compounds while retaining NO inhibitory activity, but had no effect on improving the activity of the cyclopropane form. Compounds in which the secondary hydroxyl group of DHMEQ was converted to a tertiary hydroxyl group would be excellent NF-κB inhibitor candidates because their solubility is improved without decreasing NO inhibitory activity.

Inhibition of Lipopolysaccharide-Induced Inflammatory Signaling by Soft Coral-Derived Prostaglandin A2 in RAW264.7 Cells.

Lipopolysaccharide (LPS) is a component of the outer membrane of Gram-negative bacteria and causes inflammatory diseases. We searched MeOH extracts of collected marine organisms for inhibitors of LPS-induced nitric oxide (NO) production in RAW264.7 cells and identified prostaglandin A2 (PGA2) as an active compound from the MeOH extract of the soft coral Lobophytum sp. PGA2 inhibited the production of NO and reduced the expression of inducible NO synthase (iNOS) in LPS-stimulated RAW264.7 cells. Although short preincubation with PGA2 did not inhibit LPS-induced degradation and resynthesis of IκBα, the suppressive effect of PGA2 was observed only after a prolonged incubation period prior to LPS treatment. In addition, PGA2-inhibited NO production was negated by the addition of the EP4 antagonist L161982. Thus, PGA2 was identified as an inhibitor of LPS-induced inflammatory signaling in RAW264.7 cells.

Antiapoptotic activity of methyl (3R,4E,6Z,15E)-3-hydroxyoctadecatrienoate in human cervical carcinoma HeLa cells.

Inhibitors of thapsigargin-induced cell death in human cervical carcinoma HeLa cells were screened among the metabolites of marine organisms. The MeOH extract of the cyanobacterium Rivularia sp. was found to exhibit inhibitory activity. Column chromatography purification was used to isolate methyl (3R,4E,6Z,15E)-3-hydroxyoctadecatrienoate (MHO) as the active compound. MHO was determined to inhibit apoptotic stimuli-induced cell death in HeLa cells.

Inhibitory effects of biseokeaniamide A against lipopolysaccharide-induced signal transduction.

Lipopolysaccharides (LPS) are associated with various inflammatory diseases; therefore, the inhibition of LPS-induced nitric oxide (NO) production may have extensive therapeutic applications. We searched for inhibitors of NO production in the LPS-stimulated murine macrophage-like cell line RAW264.7 from MeOH extracts of marine organisms. The MeOH extract of the marine cyanobacterium Okeania sp., collected in Okinawa, Japan, showed inhibitory activity. Biseokeaniamide A was isolated from the MeOH extract by chromatographic separation. Biseokeaniamide A inhibited NO production without cytotoxicity. It reduced inducible nitric oxide synthase levels and suppressed the expression of IL-1ß in LPS-stimulated RAW264.7 cells. Biseokeaniamide A did not inhibit IκBα degradation but inhibited IκBα expression. Thus, biseokeaniamide A, a naturally occurring lipopeptide, was identified as a selective inhibitor of LPS signal transduction.

PFG acted as an inducer of premature senescence in TIG-1 normal diploid fibroblast and an inhibitor of mitosis in the HeLa cells.

Our previous work has reported an anti-proliferative compound from moutan cortex, paeoniflorigenone which can induce cancer-selective apoptosis. However, its anti-proliferative mechanism is still unknown. According to morphology changes (hypertrophy and flattening), we hypothesized that PFG can induce senescence or inhibit cell mitosis. Here we show that PFG can induce cellular senescence, evidenced by the expression of senescence-associated ß-galactosidase, G0/G1 cell cycle arrest and permanent loss of proliferative ability, in normal TIG-1 diploid fibroblast but not cancerous HeLa cells. In cancerous HeLa cells, PFG inhibited proliferation by inducing S and G2/M cell cycle arrest and mitosis inhibition. DNA damage response was activated by PFG, interestingly the reactive oxygen species level was suppressed instead of escalated. To sum up, we report 3 new roles of PFG as, 1. inducer of premature senescence in normal TIG-1 cells, 2. inhibitor of mitosis in cancerous HeLa cells, 3. ROS scavenger. Abbreviations: PFG: Paeoniflorigenone; ROS: reactive oxygen species; ATM: ataxia telangiectasia mutated; t-BHP: tert-butyl hydroperoxide; SA-ß-gal: senescence-associatedß-galactosidase; DNA-PKcs: DNA-dependent protein kinase; γ-H2AX: H2AX phosphoryla-tion at Ser-139.

[Adult Cor Triatriatum Found by Chance at the Onset of Myocardial Infarction].

Cor triatriatum sinister is a rare congenital heart disease in which the left atrium is divided into 2 chambers by a membrane, causing resistance to the blood flow to the left ventricle. The onset of symptoms depends upon the effective size of the orifice in the membrane and the associated heart disease. Our case is a 67-year-old woman with cor triatriatum found by chance at the onset of myocardial infarction. Coronary artery bypass surgery and excision of the membrane were successfully performed. Preoperative left ventricular dysfunction was improved after surgery. Imaging examinations such as enhanced computed tomography(CT) and magnetic resonance imaging(MRI) were useful for selecting surgical approach.

Unified Total Synthesis, Stereostructural Elucidation, and Biological Evaluation of Sarcophytonolides.

Sarcophytonolides are cembranolide diterpenes isolated from the soft corals of genus Sarcophyton. Unified total synthesis of sarcophytonolides C, E, F, G, H, and J and isosarcophytonolide D was achieved. The synthetic routes feature NaHMDS- or SmI2-mediated fragment coupling, alkoxycarbonylallylation, macrolactonization, and transannular ring-closing metathesis. These total syntheses led to the absolute configurational confirmation of sarcophytonolide H, elucidation of sarcophytonolides C, E, F, and G, and revision of sarcophytonolide J and isosarcophytonolide D. We also evaluated the antifouling activity and toxicity of the synthetic sarcophytonolides H and J and their analogues as well as the cytotoxicity of the synthetic sarcophytonolides and the key synthetic intermediates.

Cyclic analogue of S-benzylisothiourea that suppresses kynurenine production without inhibiting indoleamine 2,3-dioxygenase activity.

Kynurenine is biosynthesised from tryptophan catalysed by indoleamine 2,3-dioxygenase (IDO). The abrogation of kynurenine production is considered a promising therapeutic target for immunological cancer treatment. In the course of our IDO inhibitor programme, formal cyclisation of the isothiourea moiety of the IDO inhibitor 1 afforded the 5-Cl-benzimidazole derivative 2b-6, which inhibited both recombinant human IDO (rhIDO) activity and cellular kynurenine production. Further derivatisation of 2b-6 provided the potent inhibitor of cellular kynurenine production 2i (IC50 = 0.34 µM), which unexpectedly exerted little effect on the enzymatic activity of rhIDO. Elucidation of the mechanism of action revealed that compound 2i suppresses IDO expression at the protein level by inhibiting STAT1 expression in IFN-γ-treated A431 cells. The kynurenine-production inhibitor 2i is expected to be a promising starting point for a novel approach to immunological cancer treatment.

Leptolyngbyolides, Cytotoxic Macrolides from the Marine Cyanobacterium Leptolyngbya sp.: Isolation, Biological Activity, and Catalytic Asymmetric Total Synthesis.

Four new macrolactones, leptolyngbyolides A-D, were isolated from the cyanobacterium Leptolyngbya sp. collected in Okinawa, Japan. The planar structures of leptolyngbyolides were determined by extensive NMR studies, although complete assignment of the absolute configuration awaited the catalytic asymmetric total synthesis of leptolyngbyolide C. The synthesis took advantage of the catalytic asymmetric thioamide-aldol reaction using copper(I) complexed with a chiral bidentate phosphine ligand to regulate two key stereochemistries of the molecule at the outset. The present total synthesis demonstrates the utility of this reaction for the construction of complex chemical entities. In addition to the total synthesis, this work reports that leptolyngbyolides depolymerize filamentous actin (F-actin) both in vitro and in cells. Detailed biological studies suggest the probable order of F-actin depolymerization and apoptosis caused by leptolyngbyolides.

Apoptosis-inducing activity and antiproliferative effect of Paeoniflorigenone from moutan cortex.

Ninety samples from the extracts of plants from traditional Chinese medicines were screened for antitumor activity. Paeoniflorigenone (PFG) was isolated as an active ingredient from the root of moutan cortex, which showed the strongest activity. In addition, our data indicated that PFG was cytotoxic and induced apoptosis selectively in the cancer cell lines. These effects were cancelled by the addition of caspase inhibitor Z-VAD-FMK, suggesting that it was mediated by caspase-3 activation.

[Effective Anticoagulation Therapy Prior to Surgical Excision of an Aortic Valve Papillary Fibroelastoma Diagnosed after a Transient Cerebral Ischemic Attack;Report of a Case].

Cardiac papillary fibroelastoma is reported to be the 2nd most common cardiac tumor following myxoma. Owing to the risk of embolism, early surgical excision is the treatment of choice. We report a case of effective anticoagulation therapy prior to surgical excision of an aortic valve papillary fibroelastoma. A 78-year-old man was admitted to our hospital because of transient cerebral ischemic attack. The symptom was relieved in a short period. Echocardiography revealed a tumor at the aortic valve. Cardiac computed tomography revealed a sea-anemone-like appearance of the tumor. Cardiac papillary fibroelastoma was suspected on close examination. The operation was postponed because of gingivitis that required draining. During 3 months awaiting the operation, he continued receiving anticoagulation therapy, which successfully prevented thromboembolism. Administration of anticoagulation therapy may be considered, unless early surgical excision can be performed.

Janadolide, a Cyclic Polyketide-Peptide Hybrid Possessing a tert-Butyl Group from an Okeania sp. Marine Cyanobacterium.

Janadolide, a new cyclic polyketide-peptide hybrid possessing a tert-butyl group, was isolated from an Okeania sp. marine cyanobacterium. The gross structure was elucidated by spectroscopic analyses, and the absolute configurations of the amino acid moieties were determined by acid hydrolysis and chiral-phase HPLC analyses. The absolute configuration of the two stereogenic centers in the polyketide moiety was elucidated based on a combination of degradation reactions and spectroscopic analyses including the phenyl-glycine methyl ester method. Janadolide showed potent antitrypanosomal activity with an IC50 value of 47 nM without cytotoxicity against human cells at 10 µM.

A Potent Phytotoxic Substance in Aglaia odorata Lour.

Aglaia odorata Lour. (Meliaceae) was found to have very strong allelopathic activity and a bioherbicide PORGANIC(™) was developed from its leaf extracts. However, the phytotoxic substances causing the strong allelopathic activity of the plants have not yet been determined. Therefore, we investigated allelopathic properties and phytotoxic substances in A. odorata. Aqueous EtOH extracts of A. odorata leaves inhibited root and shoot growth of garden cress (Lepidum sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), timothy (Phleum pratense), ryegrass (Lolium multiflorum), and Echinochloa crus-galli with the extract concentration-dependent manner. The extracts were then purified and a major phytotoxic substance with allelopathic activity was isolated and identified by spectral data as rocaglaol. Rocaglaol inhibited the growth of garden cress and E. crus-galli at concentrations > 0.3 and 0.03 µm, respectively. The concentrations required for 50% inhibition ranged from 0.09 to 2.5 µm. The inhibitory activity of rocaglaol on the weed species, E. crus-galli, was much greater than that of abscisic acid. These results suggest that rocaglaol may be a major contributor to the allelopathic effect of A. odorata and bioherbicide PORGANIC(™) .

Identification of a molecular target of kurahyne, an apoptosis-inducing lipopeptide from marine cyanobacterial assemblages.

In 2014, we isolated kurahyne, an acetylene-containing lipopeptide, from a marine cyanobacterial assemblage of Lyngbya sp. Kurahyne exhibited growth-inhibitory activity against human cancer cells, and induced apoptosis in HeLa cells. However, its mode of action is not yet clear. To elucidate its mode of action, we carried out several cell-based assays, and identified the intracellular target molecule of kurahyne as sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA). In addition, we found that kurahyne inhibited the differentiation of macrophages into osteoclasts.

Synthesis and structure-activity relationships for cytotoxicity and apoptosis-inducing activity of (+)-halichonine B.

Halichonine B is a sesquiterpene alkaloid isolated from the marine sponge Halichondria okadai Kadota. Halichonine B has exhibited cytotoxicity against mammalian cancer cells and induced apoptosis in the human leukemia cell line HL60. Here we established a practical route for the synthesis of halichonine B and its analogues, and we evaluated their biological activities. It was revealed that the secondary amino groups in the side chain portion are important for the strong cytotoxicity of halichonine B and that the N(11)-prenyl group is unimportant. Halichonine B and its analogues were also observed to induce apoptosis in HL60 cells.

Isolation and Structure of Kurahyne B and Total Synthesis of the Kurahynes.

Kurahyne B (2), a new analogue of kurahyne (1), was isolated from the marine cyanobacterium Okeania sp. Its gross structure was elucidated based on spectroscopic analyses, and the absolute configuration was established by total synthesis. Kurahyne B (2) inhibited the growth of both HeLa and HL60 cells, with IC50 values of 8.1 and 9.0 µM, respectively. The growth-inhibitory activity of kurahyne B was the same as kurahyne (1). In parallel, the first total synthesis of kurahyne (1) was also achieved.

Mebamamides A and B, Cyclic Lipopeptides Isolated from the Green Alga Derbesia marina.

Mebamamides A and B, new lipopeptides with four d-amino acid residues and a 3,8-dihydroxy-9-methyldecanoic acid residue, were isolated from the green alga Derbesia marina. Their gross structures were elucidated by spectroscopic and ESI-ITMS analyses. The absolute configurations except for the two leucines were revealed based on chiral-phase HPLC analyses of the acid hydrolysate and a modified Mosher's method. A distinction between D-Leu and L-Leu in the sequence was established by the application of a dansyl-Edman method to the partial acid hydrolysate. Mebamamide A did not exhibit any growth inhibitory activity against HeLa and HL60 cells at 10 µM, and mebamamide B did not exhibit any growth inhibitory activity against those cells at 100 µM. Additionally, it was suggested that mebamamide B induced the differentiation of HL60 cells into macrophage-like cells at 100 µM.

Suaveolic acid: a potent phytotoxic substance of Hyptis suaveolens.

Hyptis suaveolens (Lamiaceae) is an exotic invasive plant in many countries. Earlier studies reported that the aqueous, methanol, and aqueous methanol extract of H. suaveolens and its residues have phytotoxic properties. However, to date, the phytotoxic substances of this plant have not been reported. Therefore, the objectives of this study were isolation and identification of phytotoxic substances of H. suaveolens. Aqueous methanol extract of this plant was purified by several chromatographic runs through bioassay guided fractionation using garden cress (Lepidium sativum) as a test plant. Final purification of a phytotoxic substance was achieved by reverse phase HPLC and characterized as 14α-hydroxy-13ß-abiet-8-en-18-oic acid (suaveolic acid) by high-resolution ESI-MS, (1)H-,(13)C-NMR, CD, and specific rotation. Suaveolic acid inhibited the shoot growth of garden cress, lettuce (Lactuca sativa), Italian ryegrass (Lolium multiflorum), and barnyard grass (Echinochloa crus-galli) at concentrations greater than 30 µM. Root growth of all but lettuce was also inhibited at concentrations greater than 30 µM. The inhibitory activities were concentration dependent. Concentrations required for 50% growth inhibition of suaveolic acid for those test plant species were ranged from 76 to 1155 µM. Therefore, suaveolic acid is phytotoxic and may be responsible for the phytotoxicity of H. suaveolens plant extracts.