Effects of the wine polyphenolics quercetin and resveratrol on pro-inflammatory cytokine expression in RAW 264.7 macrophages - Ten years after

Microbial production of natural and non-natural flavonoids: Pathway engineering, directed evolution and systems/synthetic biology.

Metabolic engineering has been enabling development of high performance microbial strains for the efficient production of natural and non-natural compounds from renewable non-food biomass. Even though microbial production of various chemicals has successfully been conducted and commercialized, there are still numerous chemicals and materials that await their efficient bio-based production. Aromatic chemicals, which are typically derived from benzene, toluene and xylene in petroleum industry, have been used in large amounts in various industries. Over the last three decades, many metabolically engineered microorganisms have been developed for the bio-based production of aromatic chemicals, many of which are derived from aromatic amino acid pathways. This review highlights the latest metabolic engineering strategies and tools applied to the biosynthesis of aromatic chemicals, many derived from shikimate and aromatic amino acids, including l-phenylalanine, l-tyrosine and l-tryptophan. It is expected that more and more engineered microorganisms capable of efficiently producing aromatic chemicals will be developed toward their industrial-scale production from renewable biomass.

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Metabolic engineering of microorganisms for production of aromatic compounds

Small molecule inhibitors that target components of the spliceosome have great potential as tools to probe splicing mechanism and dissect splicing regulatory networks in cells. These compounds also hold promise as drug leads for diseases in which splicing regulation plays a critical role, including many cancers. Because the spliceosome is a complicated and dynamic macromolecular machine comprised of many RNA and protein components, a variety of compounds that interfere with different aspects of spliceosome assembly is needed to probe its function. By screening chemical libraries with high-throughput splicing assays, several labs have added to the collection of splicing inhibitors, although the mechanistic insight into splicing yielded from the initial compound hits is somewhat limited so far. In contrast, SF3B1 inhibitors stand out as a great example of what can be accomplished with small molecule tools. This group of compounds were first discovered as natural products that are cytotoxic to cancer cells, and then later shown to target the core spliceosome protein SF3B1. The inhibitors have since been used to uncover details of SF3B1 mechanism in the spliceosome and its impact on gene expression in cells. Continuing structure activity relationship analysis of the compounds is also making progress in identifying chemical features key to their function, which is critical in understanding the mechanism of SF3B1 inhibition. The knowledge is also important for the design of analogs with new and useful features for both splicing researchers and clinicians hoping to exploit splicing as pressure point to target in cancer therapy. WIREs RNA 2017, 8:e1381. doi: 10.1002/wrna.1381 For further resources related to this article, please visit the WIREs website.

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Modulating splicing with small molecular inhibitors of the spliceosome.

Glycosylation is a chemical transformation that is centrally important in all glycoscience and related technologies. Catalysts offering good control over reactivity and selectivity in synthetic glycosylations are much sought. The enzymes responsible for glycosylations in natural biosynthesis are sugar-nucleotide-dependent (Leloir) glycosyltransferases. Discovery-oriented synthesis and pilot batch production of oligosaccharides and glycosylated natural products have previously relied on Leloir glycosyltransferases. However, despite their perceived synthetic utility, Leloir glycosyltransferases are yet to see widespread application in industrial biocatalysis. Here we show progress and limitations in the development of Leloir glycosyltransferases into robust biocatalytic systems for use in glycosylations for chemical production. Obtaining highly active and stable (whole-cell) catalysts that can promote the desired glycosylation(s) coupled to an in situ sugar nucleotide supply remains a difficult problem. Opt...

Leloir Glycosyltransferases as Biocatalysts for Chemical Production

A UDP glucosyltransferase from Bacillus licheniformis was overexpressed, purified, and incubated with nucleotide diphosphate (NDP) d- and l-sugars to produce glucose, galactose, 2-deoxyglucose, viosamine, rhamnose, and fucose sugar-conjugated resveratrol glycosides. Significantly higher (90%) bioconversion of resveratrol was achieved with α-d-glucose as the sugar donor to produce four different glucosides of resveratrol: resveratrol 3-O-β-d-glucoside, resveratrol 4'-O-β-d-glucoside, resveratrol 3,5-O-β-d-diglucoside, and resveratrol 3,5,4'-O-β-d-triglucoside. The conversion rates and numbers of products formed were found to vary with the other NDP sugar donors. Resveratrol 3-O-β-d-2-deoxyglucoside and resveratrol 3,5-O-β-d-di-2-deoxyglucoside were found to be produced using TDP-2-deoxyglucose as a donor; however, the monoglycosides resveratrol 4'-O-β-d-galactoside, resveratrol 4'-O-β-d-viosaminoside, resveratrol 3-O-β-l-rhamnoside, and resveratrol 3-O-β-l-fucoside were produced from the respective sugar donors. Altogether, 10 diverse glycoside derivatives of the medically important resveratrol were generated, demonstrating the capacity of YjiC to produce structurally diverse resveratrol glycosides.

Enzymatic Biosynthesis of Novel Resveratrol Glucoside and Glycoside Derivatives

Doxorubicin and daunorubicin are two widely used anticancer drugs containing deoxyaminosugar unit in their structure. Altering the sugar moiety could generate novel drugs, which could have different biological potency than daunorubicin and doxorubicin. In this study, daunorubicinone was used as a substrate for the production of two different novel glucoside derivatives via enzymatic glycosylation, and their physical and biological activities were assessed and compared with standard compounds. A one-pot enzymatic glycosylation system was designed in vitro to maintain continuous generation of UDP-α- d -glucose, which is used as the donor substrate by the glycosyltransferase enzyme, YjiC, for the glycosylation of acceptor molecule, daunorubicinone, aglycone of daunorubicin. The result indicates an increased conversion (∼74.8%) of daunorubicinone 7-O-α- d -glucoside and ∼22.2% of daunorubicinone-7,9-di-O-α- d -glucoside in one-pot UDP-α- d -glucose recycling system in comparison to regular reaction at 90 min incubation period. Both the glucosylated daunorubicinone exhibited improved water solubility, and stability over a wide range of pH (4.5–8.5) and high temperatures. However, anticancer activity assay against four different cancer cell lines showed complete loss of anticancer property upon glucosylation of daunorubicinone.

Synthetic analog of anticancer drug daunorubicin from daunorubicinone using one-pot enzymatic UDP-recycling glycosylation

Antiangiogenesis is now thought of as one of the most important approaches for anticancer therapy. In this study, we determined the antiangiogenic property of herboxidiene, a polyketide natural product. Herboxidiene effectively inhibited the proliferation of human umbilical vein endothelial cells (HUVECs) at concentrations not exhibiting cytotoxicity. Furthermore, the natural product significantly suppressed vascular endothelial growth factor-induced invasion and tube formation in HUVECs as well as neovascularization of the chorioallantoic membrane in developing chick embryos. We also identified an association between the antiangiogenic activity of herboxidiene and the downregulation of both the phosphorylation of VEGF receptor 2 (KDR/Flk-1) and the expression of hypoxia-inducible factor-1α at the transcriptional level. These results suggest that herboxidiene functions as a potential antiangiogenic agent and may be applicable for anticancer therapy by targeting tumor angiogenesis.

Antiangiogenic activity of herboxidiene via downregulation of vascular endothelial growth factor receptor-2 and hypoxia-inducible factor-1α

In vitro single-vessel enzymatic synthesis of novel Resvera-A glucosides.

Epothilone A is a derivative of 16-membered polyketide natural product, which has comparable chemotherapeutic effect like taxol. Introduction of sialic acids to these chemotherapeutic agents could generate interesting therapeutic glycoconjugates with significant effects in clinical studies. Since, most of the organisms biosynthesize sialic acids in their cell surface, they are key mediators in cellular events (cell-cell recognition, cell-matrix interactions). Interaction between such therapeutic sugar parts and cellular polysaccharides could generate interesting result in drugs like epothilone A. Based on this hypothesis, epothilone A glucoside (epothilone A 6-O-β-D-glucoside) was further decorated by conjugating enzymatically galactose followed by sialic acids to generate epothilone A 7-O-β-D-glucopyranosyl, 4'-O-α-D-galactoside i.e., lactosyl epothilone A (lac epoA) and two sialosides of epothilone A namely epothilone A 7-O-β-D-glucopyranosyl, 4'-O-α-D-galactopyranosyl 3″-O-α-N-acetyl neuraminic acid and epothilone A 7-O-β-D-glucopyranosyl, 4'-O-α-D-galactopyranosyl 6″-O-α-N-acetylneuraminic acid i.e., 3'sialyllactosyl epothilone A: 3'SL-epoA, and 6'sialyllactosyl epothilone A: 6'SL-epoA, respectively. These synthesized analogs were spectroscopically analyzed and elucidated, and biologically validated using HUVEC and HCT116 cancer cell lines.

Ju Yong Shin

Papers

Enzymatic Biosynthesis of Novel Resveratrol Glucoside and Glycoside Derivatives

Synthetic analog of anticancer drug daunorubicin from daunorubicinone using one-pot enzymatic UDP-recycling glycosylation

Antiangiogenic activity of herboxidiene via downregulation of vascular endothelial growth factor receptor-2 and hypoxia-inducible factor-1α

In vitro single-vessel enzymatic synthesis of novel Resvera-A glucosides.

Enzymatic synthesis of lactosylated and sialylated derivatives of epothilone A.