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.

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.

Self-organization, quality control, and preclinical studies of human iPSC-derived retinal sheets for tissue-transplantation therapy.

Three-dimensional retinal organoids (3D-retinas) are a promising graft source for transplantation therapy. We previously developed self-organizing culture for 3D-retina generation from human pluripotent stem cells (hPSCs). Here we present a quality control method and preclinical studies for tissue-sheet transplantation. Self-organizing hPSCs differentiated into both retinal and off-target tissues. Gene expression analyses identified the major off-target tissues as eye-related, cortex-like, and spinal cord-like tissues. For quality control, we developed a qPCR-based test in which each hPSC-derived neuroepithelium was dissected into two tissue-sheets: inner-central sheet for transplantation and outer-peripheral sheet for qPCR to ensure retinal tissue selection. During qPCR, tissue-sheets were stored for 3-4 days using a newly developed preservation method. In a rat tumorigenicity study, no transplant-related adverse events were observed. In retinal degeneration model rats, retinal transplants differentiated into mature photoreceptors and exhibited light responses in electrophysiology assays. These results demonstrate our rationale toward self-organizing retinal sheet transplantation therapy.

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.

Structure-Activity Relationship and In Silico Evaluation of cis- and trans-PCPA-Derived Inhibitors of LSD1 and LSD2.

trans-2-Phenylcycloproylamine (trans-PCPA) has been used as the scaffold to develop covalent-binding inhibitors against lysine-specific demethylase 1 (LSD1/KDM1A), a therapeutic target for several cancers. However, the effects of different structural moieties on the inhibitory activity, selectivity, and reactivity of these derivatives, including the cis isomers, against LSD1 and its paralogue LSD2/KDM1B are not fully understood. Here we synthesized 65 cis- and trans-PCPA derivatives and evaluated their inhibitory activity against LSD1 and LSD2. One of the derivatives, 7c (cis-4-Br-2,5-F2-PCPA; S1024), inhibited LSD1 and LSD2 with K i values of 0.094 µM and 8.4 µM, respectively, and increased the level of dimethylated histone H3 at K4 in CCRF-CEM cells. A machine learning-based regression model (Q 2 = 0.61) to predict LSD1-inhibitory activity was also constructed and showed a good prediction accuracy (R 2 = 0.81) for 12 test-set compounds, including 7c. The present methodology would be useful when designing covalent-binding inhibitors for other enzymes.

Isolation of Caldorazole, a Thiazole-Containing Polyketide with Selective Cytotoxicity under Glucose-Restricted Conditions.

Caldorazole (1) was isolated from the marine cyanobacterium Caldora sp. collected on Ishigaki Island, Okinawa, Japan. Its structure was determined to be a new polyketide that contained two thiazole rings and an O-methylenolpyruvamide moiety. Caldorazole (1) showed strong cytotoxicity toward tumor cells that had been seeded at a high density. Cell death induced by 1 in HeLa and A431 cells was also observed only in the presence of the glycolysis blocker 2-deoxy-d-glucose (2DG). Co-treatment with 1 and 2DG remarkably decreased ATP levels in these cells. Furthermore, 1 selectively inhibited complex I in the mitochondrial respiratory chain. Thus, 1 was demonstrated to exert cytotoxicity toward human tumor cells by blocking mitochondrial respiration.

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.

Discovery of Carbono(di)thioates as Indoleamine 2,3-Dioxygenase 1 Inhibitors.

A structure-activity relationship study unexpectedly showed that carbonothioates 4a and 4b, obtained by a unique alkaline hydrolysis of 2-alkylthio-oxazolines 3a and 3b, respectively, are a novel scaffold for indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors. Derivatization of the carbonothioates enhanced inhibitory activity against IDO1 and cellular kynurenine production without cytotoxicity and led to the discovery of the related scaffolds carbonodithioates 5 and cyanocarbonimidodithioates 6 as IDO1 inhibitors. Incorporation of an OH group provided the most potent analogue 5i. UV-visible absorption spectroscopy of the Soret band, as well as docking and peptide mapping studies, suggested that these molecules bind to the heme in the active site of IDO1. Our unique IDO1 inhibitors are potential leads for future development.

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.

[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.

Hypereosinophilia and Multisite Vasculopathy of Fibromuscular Dysplasia: A Case Report.

The impact of blood disorders on fibromuscular dysplasia is unknown, and cardiovascular surgery results are also unclear. Furthermore, there are only a few case reports about the association between fibromuscular dysplasia and blood disorders. We report a case of a coronary bypass surgery and an aortic root replacement for a patient who is hypereosinophilic with multisite vasculopathy of fibromuscular dysplasia, including that of the coronary artery and saphenous vein, which was diagnosed by a histopathologic examination after an autopsy was performed 5 months after surgery. The outcome of cardiovascular surgery can be unfavorable for fibromuscular dysplasia. Blood disorders may also have an impact on the outcome.

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.

Minnamide A, a Linear Lipopeptide from the Marine Cyanobacterium Okeania hirsuta.

Minnamide A is a lipopeptide with a unique repeating structure consisting of hydroxy and proposed ß-branched methyl groups. The absolute configuration of minnamide A was determined by a combination of chemical degradation, chiral HPLC analyses, and synthetic methods. Minnamide A showed growth-inhibitory activity toward HeLa cells with an IC50 value of 0.17 µM and rapidly induced cell death at a concentration of 2 µM. Minnamide A induced the copper-mediated accumulation of reactive oxygen species.

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.

Direct oral anticoagulant therapy as an alternative to surgery for the treatment of a patient with a floating thrombus in the ascending aorta and pulmonary embolism.

A floating thrombus in the ascending aorta was incidentally discovered in a patient with a descending thoracic aortic aneurysm and a history of alcoholism. The patient developed deep venous thrombosis and pulmonary embolism. However, he refused to undergo surgical excision of the thrombus in the ascending aorta. Therefore, treatment with rivaroxaban was administered for 3 months, and it completely dissolved the thrombus. Anticoagulant therapy may be an alternative treatment when surgery cannot be performed.

Involvement of allelopathy in inhibition of understory growth in red pine forests.

Japanese red pine (Pinus densiflora Sieb. et Zucc.) forests are characterized by sparse understory vegetation although sunlight intensity on the forest floor is sufficient for undergrowth. The possible involvement of pine allelopathy in the establishment of the sparse understory vegetation was investigated. The soil of the red pine forest floor had growth inhibitory activity on six test plant species including Lolium multiflorum, which was observed at the edge of the forest but not in the forest. Two growth inhibitory substances were isolated from the soil and characterized to be 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid. Those compounds are probably formed by degradation process of resin acids. Resin acids are produced by pine and delivered into the soil under the pine trees through balsam and defoliation. Threshold concentrations of 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid for the growth inhibition of L. multiflorum were 30 and 10µM, respectively. The concentrations of 15-hydroxy-7-oxodehydroabietate and 7-oxodehydroabietic acid in the soil were 312 and 397µM, respectively, which are sufficient concentrations to cause the growth inhibition because of the threshold. These results suggest that those compounds are able to work as allelopathic agents and may prevent from the invasion of herbaceous plants into the forests by inhibiting their growth. Therefore, allelopathy of red pine may be involved in the formation of the sparse understory vegetation.

[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.

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.