RESUMEN
C-Glycosides are critical motifs embedded in many bioactive natural products. The inert C-glycosides are privileged structures for developing therapeutic agents owing to their high chemical and metabolic stability. Despite the comprehensive strategies and tactics established in the past few decades, highly efficient C-glycoside syntheses via C-C coupling with excellent regio-, chemo-, and stereoselectivity are still needed. Here, we report the efficient Pd-catalyzed glycosylation of C-H bonds promoted by weak coordination with native carboxylic acids without external directing groups to install various glycals to the structurally diverse aglycon parts. Mechanistic evidence points to the participation of a glycal radical donor in the C-H coupling reaction. The method has been applied to a wide range of substrates (over 60 examples), including many marketed drug molecules. Natural product- or drug-like scaffolds with compelling bioactivities have been constructed using a late-stage diversification strategy. Remarkably, a new potent sodium-glucose cotransporter-2 inhibitor with antidiabetic potential has been discovered, and the pharmacokinetic/pharmacodynamic profiles of drug molecules have been changed using our C-H glycosylation approach. The method developed here provides a powerful tool for efficiently synthesizing C-glycosides to facilitate drug discovery.
RESUMEN
Deoxynivalenol (DON), one of the main mycotoxins with enteric toxicity, genetic toxicity, and immunotoxicity, and is widely found in corn, barley, wheat, and rye. In order to achieve effective detoxification of DON, the least toxic 3-epi-DON (1/357th of the toxicity of DON) was chosen as the target for degradation. Quinone-dependent dehydrogenase (QDDH) reported from Devosia train D6-9 detoxifies DON by converting C3-OH to a ketone group with toxicity of less than 1/10 that of DON. In this study, the recombinant plasmid pPIC9K-QDDH was constructed and successfully expressed in Pichia pastoris GS115. Within 12 h, recombinant QDDH converted 78.46% of the 20 µg/mL DON to 3-keto-DON. Candida parapsilosis ACCC 20221 was screened for its activity in reducing 86.59% of 3-keto-DON within 48 h; its main products were identified as 3-epi-DON and DON. In addition, a two-step method was performed for epimerizing DON: 12 h catalysis by recombinant QDDH and 6 h transformation of the C. parapsilosis ACCC 20221 cell catalyst. The production rates of 3-keto-DON and 3-epi-DON were 51.59% and 32.57%, respectively, after manipulation. Through this study, effective detoxification of 84.16% of DON was achieved, with the products being mainly 3-keto-DON and 3-epi-DON.
Asunto(s)
Micotoxinas , Tricotecenos , Candida parapsilosis/metabolismo , Tricotecenos/toxicidad , Micotoxinas/metabolismo , Quinonas , Contaminación de Alimentos/análisisRESUMEN
Farnesoid X receptor (FXR), a member of the nuclear receptor superfamily, plays an important role in maintaining or reversing metabolic homeostasis during the development of liver diseases. However, developing FXR modulators to intervene in FXR-related diseases is still an unmet clinical need. Therefore, it is significant to develop novel small-molecule agonists for drug discovery targeting FXR. Through a high-throughput chemical screen and follow-up biological validations, we first identified the natural product Fargesone A (FA) as a potent and selective FXR agonist. The limited, variable supply of FA from natural product isolation, however, has impeded its biological exploration and potential drug development. Accordingly, we have developed a biomimetic and scalable total synthesis of FA in nine steps that provides a solution to the supply of FA. Enabled by chemical synthesis, the in vivo efficacy of FA has been further investigated. The results showed that FA alleviates hepatocyte lipid accumulation and cell death in an FXR-dependent manner. Moreover, treatment of bile duct ligation (BDL)-induced liver disorder with FA ameliorates pathological features in mice. Therefore, our work lays the foundation to develop new small-molecule FXR agonists as a potential therapy for liver diseases.
RESUMEN
Zearalenone (ZEA), a nonsteroidal estrogenic mycotoxin produced by multiple Fusarium species, contaminates cereals and threatens the health of both humans and animals by inducing hepatotoxicity, immunotoxicity, and genotoxicity. A new alkali tolerant enzyme named Ase, capable of degrading ZEA without H2O2, was derived from Acinetobacter sp. SM04 in this study. The Ase gene shares 97% sequence identity with hypothetical proteins from Acinetobacter pittii strain WCHAP 100004 and YMC 2010/8/T346 and Acinetobacter calcoaceticus PHEA-2, respectively. Based on the Acinetobacter genus database, the gene encoding Ase was cloned and extracellularly expressed in Escherichia coli BL21. After degrading 88.4% of ZEA (20 µg/mL), it was confirmed through MCF-7 cell proliferation assays that Ase can transform ZEA into a nonestrogenic toxic metabolite. Recombinant Ase (molecular weight: 28 kDa), produced by E. coli BL21/pET32a(+)-His-Ase, was identified as an oxygen-utilizing and cytochrome-related enzyme with optimal activity at 60 °C and pH 9.0.
Asunto(s)
ZearalenonaRESUMEN
The aim of the present study was to investigate the potential role of long noncoding RNA Fer1like family member 4 (FER1L4) in the proliferation of hepatocellular carcinoma (HCC) through the regulation of phosphatase and tensin homolog (PTEN) expression. Reverse transcriptionquantitative polymerase chain reaction (RTqPCR) was used to detect the expression levels of FER1L4 and PTEN mRNA in HCC tissues, and western blotting was performed to measure the protein expression level of PTEN; MTT and colony formation assays were performed to detect the cell proliferative ability. Furthermore, nude mice were injected with transfected HCC cells and the tumor volume and weight were measured. The results indicated that FER1L4 was expressed at a low level in human HCC tissues compared with adjacent normal tissues. Functional studies indicated that FER1L4 may inhibit the proliferative ability of HCC cells. In addition, PTEN was highly expressed in HCC tissues compared with normal adjacent tissues and was positively associated with FER1L4. In addition, it was demonstrated that FER1L4 inhibited the proliferative ability of HCC cells in vitro, and silencing FER1L4 expression by small interfering RNAs promoted the growth of HCC tumors in vivo. Therefore, FER1L4 may be a potent therapeutic target for HCC.