Transcriptome profiles of Streptomyces clavuligerus strains producing different titers of clavulanic acid.

Streptomyces clavuligerus NRRL 3585 is a native producer of clavulanic acid (CA), a clinically used ß-lactamase inhibitor, and is widely used as an industrial strain for the production of antibiotics. Selective random mutagenesis has successfully generated the improved CA-producing S. clavuligerus mutant strains as well as the strain with the loss of CA biosynthesis. To understand the molecular mechanisms associated with the improved CA-production potential, genome-scale RNA-sequencing-based transcriptional data were obtained for the wild-type S. clavuligerus strain and its three mutant strains. Total RNA samples for each strain were collected across four different growth stages, and all 32 sequencing data points exhibited an average Phred score of 36. The high-quality genome-scale transcriptional profile of S. clavuligerus strains with varied CA biosynthetic potential provides valuable insights and new opportunities for discovering efficient metabolic engineering strategies for the development of improved industrial strains.

Prenylated Chrysin Derivatives as Partial PPARγ Agonists with Adiponectin Secretion-Inducing Activity.

Decreased circulating adiponectin levels are associated with an increased risk of human metabolic diseases. The chemical-mediated upregulation of adiponectin biosynthesis has been proposed as a novel therapeutic approach to managing hypoadiponectinemia-associated diseases. In preliminary screening, the natural flavonoid chrysin (1) exhibited adiponectin secretion-inducing activity during adipogenesis in human bone marrow mesenchymal stem cells (hBM-MSCs). Here, we provide the 7-prenylated chrysin derivatives, chrysin 5-benzyl-7-prenylether compound 10 and chrysin 5,7-diprenylether compound 11, with the improved pharmacological profile compared with chrysin (1). Nuclear receptor binding and ligand-induced coactivator recruitment assays revealed that compounds 10 and 11 functioned as peroxisome proliferator-activated receptor (PPAR)γ partial agonists. These findings were supported by molecular docking simulation, followed by experimental validation. Notably, compound 11 showed PPARγ binding affinity as potent as that of the PPARγ agonists pioglitazone and telmisartan. This study presents a novel PPARγ partial agonist pharmacophore and suggests that prenylated chrysin derivatives have therapeutic potential in various human diseases associated with hypoadiponectinemia.

Computational Prediction of the Phenotypic Effect of Flavonoids on Adiponectin Biosynthesis.

In silico machine learning applications for phenotype-based screening have primarily been limited due to the lack of machine-readable data related to disease phenotypes. Adiponectin, a nuclear receptor (NR)-regulated adipocytokine, is relatively downregulated in human metabolic diseases. Here, we present a machine-learning model to predict the adiponectin-secretion-promoting activity of flavonoid-associated phytochemicals (FAPs). We modeled a structure-activity relationship between the chemical similarity of FAPs and their bioactivities using a random forest-based classifier, which provided the NR activity of each FAP as a probability. To link the classifier-predicted NR activity to the phenotype, we next designed a single-cell transcriptomics-based multiple linear regression model to generate the relative adiponectin score (RAS) of FAPs. In experimental validation, estimated RAS values of FAPs isolated from Scutellaria baicalensis exhibited a significant correlation with their adiponectin-secretion-promoting activity. The combined cheminformatics and bioinformatics approach enables the computational reconstruction of phenotype-based screening systems.

Discovery of PPARγ and glucocorticoid receptor dual agonists to promote the adiponectin and leptin biosynthesis in human bone marrow mesenchymal stem cells.

Adiponectin and leptin are major adipocytokines that control crosstalk between adipose tissue and other organ systems. Hypoadiponectinemia and hypoleptinemia are associated with human metabolic diseases. Compounds with adipocytokine biosynthesis-stimulating activities could be developed as therapeutics against diverse metabolic conditions. In phenotypic screening with human bone marrow mesenchymal stem cells (hBM-MSCs), (E)-4-hydroxy-3-(3-(4-hydroxy-3-methoxyphenyl)acryloyl)-6-methyl-2H-pyran-2-one (1) was identified to increase adiponectin biosynthesis during adipogenesis and simultaneously to stimulate leptin production. Using the compound 1 structure, the structure-activity relationship study was performed to discover more potent compounds stimulating both adiponectin and leptin production. (E)-3-(3-(2-fluoropyridin-4-yl)acryloyl)-4-hydroxy-6-methyl-2H-pyran-2-one (11) exhibited the most potent adiponectin (EC50, 2.87 µM) and leptin (EC50, 2.82 µM) biosynthesis-stimulating activities in hBM-MSCs. In a target identification study, compound 11 was characterized as a dual modulator binding to both peroxisome proliferator-activated receptor (PPAR) γ and glucocorticoid receptor (GR). This study provides a novel pharmacophore for PPARγ/GR dual modulators with therapeutic potential against human metabolic diseases.

Macakurzin C Derivatives as a Novel Pharmacophore for Pan-Peroxisome Proliferator-Activated Receptor Modulator.

The natural flavonoid macakurzin C (1) exhibited adiponectin biosynthesis-inducing activity during adipogenesis in human bone marrow mesenchymal stem cells and its molecular mechanism was directly associated with a pan-peroxisome proliferator-activated receptor (PPAR) modulator affecting all three PPAR subtypes α, γ, and δ. In this study, increases in adiponectin biosynthesis-inducing activity by macakurzin C derivatives (2-7) were studied. The most potent adiponectin biosynthesis-inducing compound 6, macakurzin C 3,5-dimethylether, was elucidated as a dual PPARα/γ modulator. Compound 6 may exhibit the most potent activity because of the antagonistic relationship between PPARδ and PPARγ. Docking studies revealed that the O-methylation of macakurzin C to generate compound 6 significantly disrupted PPARδ binding. Compound 6 has therapeutic potential in hypoadiponectinemia-related metabolic diseases.

Abiraterone Acetate Attenuates SARS-CoV-2 Replication by Interfering with the Structural Nucleocapsid Protein.

The drug repurposing strategy has been applied to the development of emergency COVID-19 therapeutic medicines. Current drug repurposing approaches have been directed against RNA polymerases and viral proteases. Recently, we found that the inhibition of the interaction between the SARS-CoV-2 structural nucleocapsid (N) and spike (S) proteins decreased viral replication. In this study, drug repurposing candidates were screened by in silico molecular docking simulation with the SARS-CoV-2 structural N protein. In the ChEMBL database, 1994 FDA-approved drugs were selected for the in silico virtual screening against the N terminal domain (NTD) of the SARS-CoV-2 N protein. The tyrosine 109 residue in the NTD of the N protein was used as the center of the ligand binding grid for the docking simulation. In plaque forming assays performed with SARS-CoV-2 infected Vero E6 cells, atovaquone, abiraterone acetate, and digoxin exhibited a tendency to reduce the size of the viral plagues without affecting the plaque numbers. Abiraterone acetate significantly decreased the accumulation of viral particles in the cell culture supernatants in a concentration-dependent manner. In addition, abiraterone acetate significantly decreased the production of N protein and S protein in the SARS-CoV-2-infected Vero E6 cells. In conclusion, abiraterone acetate has therapeutic potential to inhibit the viral replication of SARS-CoV-2.

Adiponectin-Secretion-Promoting Cyclic Peptide-Polyketide Hybrids from a Halophyte-Associated Fungus, Colletotrichum gloeosporioides JS0417.

Three new cyclic peptide-polyketide hybrids (1-3) and two new chaetiacandin-type polyketides (4 and 5) along with nine known compounds were isolated from cultures of a halophyte-associated fungus, Colletotrichum gloeosporioides JS0417. Spectroscopic analysis revealed that 1-3 were cyclic depsipeptides where 3,5,11-trihydroxy-2,6-dimethyldodecanoic acid was linked to two amino acids through amide and ester bonds to form a 12-membered ring. Relative and absolute configurations for the peptides were determined with spectroscopic analysis and chemical reactions. The cyclic depsipeptides 2 and 6 were determined to act as strong adiponectin-secretion-promoting modulators with potential to treat metabolic diseases associated with hypoadiponectinemia. Notably, a known compound, tryptophol, significantly inhibited PGE2 synthesis and also promoted adiponectin secretion, exhibiting a similar biological activity profile to aspirin, but with greater potency. The presence of an isoleucine moiety and non-glycosylation may be important for biological activity of the cyclic peptide-polyketide hybrids, and non-methoxylation of the side chain may influence activity of the indole derivatives.

Sunscreen filter octocrylene is a potential obesogen by acting as a PPARγ partial agonist.

Octocrylene (OC) is an extensively prescribed organic ultraviolet B filter used in sunscreen products. Due to its extensive use, a significant level of OC is detected in marine and freshwater environments. Notably, the bioaccumulation of OC in aquatic biota may affect human health. In this study, the effect of OC on metabolism was investigated using the adipogenesis model of human bone marrow mesenchymal stem cells (hBM-MSCs). OC promoted adiponectin production during adipogenesis in hBM-MSCs compared to the vehicle-treated control (EC50, 29.6 µM). In target identification, OC directly bound to peroxisome proliferator-activated receptor (PPAR) γ (Ki, 37.8 µM). OC-bound PPARγ also significantly recruited nuclear receptor coactivator proteins SRC-1 (EC50, 54.1 µM) and SRC-2 (EC50, 58.6 µM). In the molecular docking simulation study, the optimal ligand-binding mode of OC suggested that OC is a PPARγ partial agonist. A competitive analysis with a PPARγ full agonist pioglitazone revealed that OC acted as a PPARγ partial agonist. OC altered the gene transcription profile of lipid-metabolism associated enzymes in normal human keratinocytes, primarily exposed human cells after the application of sunscreens. In conclusion, OC is a potential metabolic disrupting obesogen.

Galangin 3-benzyl-5-methylether derivatives function as an adiponectin synthesis-promoting peroxisome proliferator-activated receptor γ partial agonist.

The upregulation of adiponectin production has been suggested as a novel strategy for the treatment of metabolic diseases. Galangin, a natural flavonoid, exhibited adiponectin synthesis-promoting activity during adipogenesis in human bone marrow mesenchymal stem cells. In target identification, galangin bound both peroxisome proliferator-activated receptor (PPAR) γ and estrogen receptor (ER) ß. Novel galangin derivatives were synthesized to improve adiponectin synthesis-promoting compounds by increasing the PPARγ activity of galangin and reducing its ERß activity, because PPARγ functions can be inhibited by ERß. Three galangin 3-benzyl-5-methylether derivatives significantly promoted adiponectin production by 2.88-, 4.47-, and 2.76-fold, respectively, compared to the effect of galangin. The most potent compound, galangin 3-benzyl-5,7-dimethylether, selectively bound to PPARγ (Ki, 1.7 µM), whereas it did not bind to ERß. Galangin 3-benzyl-5,7-dimethylether was identified as a PPARγ partial agonist in docking and pharmacological competition studies, suggesting that it may have diverse therapeutic potential in a variety of metabolic diseases.

2-Phenyl-8-(1-phenylallyl)-chromenone compounds have a pan-PPAR modulator pharmacophore.

Adiponectin is an adipocytokine with insulin-sensitizing, anti-atherogenic, and anti-inflammatory properties. Adiponectin secretion-inducing compounds have therapeutic potential in a variety of metabolic diseases. Phenotypic screening led to the discovery that 5,7-dihydroxy-8-(1-(4-hydroxy-3-methoxyphenyl)allyl)-2-phenyl-4H-chromen-4-one (compound 1) had adiponectin secretion-inducing activity during adipogenesis in human bone marrow mesenchymal stem cells (hBM-MSCs). Compound 1 was originally reported to be an anti-cancer chemical isolated from natural honeybee propolis, and its adiponectin secretion-inducing activity was found in non-cytotoxic concentrations. In a target identification study, compound 1 and its potent synthetic derivative compound 5 were shown to be novel pan-peroxisome proliferator-activator receptor (PPAR) modulators. Molecular docking models with PPARs have indicated that the binding modes of chromenone compounds preferentially interacted with the hydrophobic ligand binding pocket of PPARs. In addition, chromenone compounds have been shown to result in different phenotypic outcomes in the transcriptional regulation of lipid metabolic enzymes than those of selective PPAR mono-agonists for PPARα, PPARγ, and PPARδ. In line with the pharmacology of adiponectin and PPAR pan-modulators, compounds 1 and 5 may have diverse therapeutic potentials to treat cancer and metabolic diseases.