Toyonobu Usuki

Elastin, an extracellular matrix component that contributes to vascular integrity, is progressively degraded during vascular injury including atherosclerosis. We assessed circulating desmosine (DES) and isodesmosine (IDES), elastin-specific crosslinking amino acids, as indicators of arterial elastin degradation by isotope-dilution liquid chromatography-tandem mass spectrometry. Thirty-eight patients with atherosclerotic ischemic heart disease (IHD) and 30 age- and sex-matched healthy controls were enrolled. Plasma concentrations of both DES and IDES were significantly higher in IHD patients than in controls. The area under the receiver operating characteristic curve for total desmosines (DES + IDES) was 0.763. Multivariable analysis revealed that traditional risk factors for atherosclerosis were not significantly associated with plasma concentrations of desmosines. These findings suggest that circulating desmosines reflect arterial wall degeneration in atherosclerosis and are independent of traditional risk factors.

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy with poor prognosis, frequent relapse, and treatment-related toxicity. The discovery of novel anti-leukemic agents with improved selectivity remains an urgent clinical need. In this study, rhizomes of Angiopteris evecta, a medicinal plant used in Thai traditional medicine, were collected from twelve locations in Thailand and extracted using solvents of increasing polarity. Among thirty-six crude fractional extracts, the ethyl acetate crude fractional extract from source No. 003 (AE EtOAc No. 003) exhibited the strongest cytotoxic activity against KG-1a and EoL-1 leukemic cell lines, with low toxicity toward normal peripheral blood mononuclear cells. Bioactivity-guided fractionation yielded the ternary mixture, a furanone-rich mixture dominated by 5-(1-hydroxyethyl)-dihydro-2-furanone. The ternary mixture inhibited leukemic cell proliferation by inducing apoptosis, causing cell cycle arrest, and downregulating WT1 expression in EoL-1 cells. Network pharmacology and molecular docking analyses implicated AKT1, MAPK signaling, apoptosis-related pathways, and WT1 as key molecular targets. In addition, AE EtOAc No. 003 and the ternary mixture suppressed TNF-α and IL-6 production in LPS-stimulated macrophages. Collectively, A. evecta-derived furanone compounds represent promising lead candidates for anti-leukemic drug development.

Ecological interactions in the soil are often mediated by small molecules, which can later become valuable drugs. The cellular slime mould Dictyostelium discoideum is a soil microbe with a life cycle consisting of unicellular (amoeba) and multicellular phases (fruiting bodies). After Dictyostelium amoebae have consumed all available bacteria, they form stalked fruiting bodies to aid dispersal of the spores. The dying stalk cells repurpose a hybrid polyketide synthase to make abundant chlorinated metabolites, which persist in their fruiting bodies. The most abundant of the chlorinated metabolites, CDF-1, is a chlorinated dibenzofuran, which was shown to be an effective antimicrobial, being roughly as potent as ampicillin. Here, we identify CDF-2 and -3 by purification, followed by MS and NMR, after increasing their yields by using producer species and growth condition optimisation. Similar to CDF-1, CDF-2 and -3 are chlorinated dibenzofurans and exhibit more potent antibacterial activity against Gram-positive bacteria than ampicillin. We propose that the ecological function of CDF-2 and -3 is to protect the dormant spores from degradative bacteria.

Elastic lamellae are stratified extracellular structures essential for maintaining the integrity of large vessels. While numerous studies have elucidated the roles of individual molecules in elastic fiber formation, the mechanisms governing three-dimensional (3D) elastic fiber assembly in blood vessels remain incompletely understood. Advancing comprehensive understanding of these mechanisms requires overcoming the limitation of genetically modified animal models and conventional planar culture systems. Here, we present a 3D experimental vascular model (3D-VM) consisting of rat embryonic aortic smooth muscle cells (SMCs) that recapitulates multilayered SMCs and SMC-derived cross-linked elastic lamellae, constructed by a layer-by-layer technique utilizing fibronectin and gelatin. Electron microscopy confirmed the presence of stratified elastic lamellae, and mass spectrometry detected abundant desmosines and isodesmosines. The model exhibited an average burst pressure of 0.178 ± 0.042 MPa and withstood arterial pressures for at least 5 months after implantation in the adult rat aorta. Transcriptomic analysis revealed a gene expression profile in the 3D-VM that closely resembled that of native rat aortic tissues rather than planar-cultured SMCs. Gene ontology and pathway enrichment analyses identified significant positive correlations with genes associated with vascular development and extracellular matrix organization. Several elastic fiber-related genes were highly expressed at mRNA and protein levels in the 3D-VM compared with the adult aorta. Furthermore, fibulin-4 is a well-recognized elastic fiber component, and the 3D-VM generated with fibulin-4-deficient SMCs failed to form elastic fibers, highlighting the model's utility. These results suggest that the 3D-VM provides a platform for investigating the molecular mechanisms underlying 3D elastic fiber formation. STATEMENT OF SIGNIFICANCE: Elastic fibers confer tissues with distensibility and elastic recoil, allowing tissues to withstand repeated mechanical stress throughout life, particularly in dynamic organs such as arteries. Understanding the molecular mechanisms that govern elastic fiber formation is essential for developing therapeutic strategies for progressive diseases associated with elastic fiber dysfunction. To overcome the limitations of genetically modified animal models and conventional planar culture systems, which primarily elucidate the roles of individual molecules, we successfully established a three-dimensional vascular model composed of multilayered smooth muscle cells (SMCs) and SMC-derived cross-linked functional elastic lamellae. This model enables spatiotemporal analysis of elastic fiber formation and provides a platform for investigating the precise mechanisms that coordinate the interplay among multiple molecules.