Characterization of the WRKY Gene Family Related to Anthocyanin Biosynthesis and the Regulation Mechanism under Drought Stress and Methyl Jasmonate Treatment in Lycoris radiata.

Lycoris radiata, belonging to the Amaryllidaceae family, is a well-known Chinese traditional medicinal plant and susceptible to many stresses. WRKY proteins are one of the largest families of transcription factors (TFs) in plants and play significant functions in regulating physiological metabolisms and abiotic stress responses. The WRKY TF family has been identified and investigated in many medicinal plants, but its members and functions are not identified in L. radiata. In this study, a total of 31 L. radiata WRKY (LrWRKY) genes were identified based on the transcriptome-sequencing data. Next, the LrWRKYs were divided into three major clades (Group I-III) based on the WRKY domains. A motif analysis showed the members within same group shared a similar motif component, indicating a conservational function. Furthermore, subcellular localization analysis exhibited that most LrWRKYs were localized in the nucleus. The expression pattern of the LrWRKY genes differed across tissues and might be important for Lycoris growth and flower development. There were large differences among the LrWRKYs based on the transcriptional levels under drought stress and MeJA treatments. Moreover, a total of 18 anthocyanin components were characterized using an ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) analysis and pelargonidin-3-O-glucoside-5-O-arabinoside as well as cyanidin-3-O-sambubioside were identified as the major anthocyanin aglycones responsible for the coloration of the red petals in L. radiata. We further established a gene-to-metabolite correlation network and identified LrWRKY3 and LrWRKY27 significant association with the accumulation of pelargonidin-3-O-glucoside-5-O-arabinoside in the Lycoris red petals. These results provide an important theoretical basis for further exploring the molecular basis and regulatory mechanism of WRKY TFs in anthocyanin biosynthesis and in response to drought stress and MeJA treatment.

Recent Research Progress in Taxol Biosynthetic Pathway and Acylation Reactions Mediated by Taxus Acyltransferases.

Taxol is one of the most effective anticancer drugs in the world that is widely used in the treatments of breast, lung and ovarian cancer. The elucidation of the taxol biosynthetic pathway is the key to solve the problem of taxol supply. So far, the taxol biosynthetic pathway has been reported to require an estimated 20 steps of enzymatic reactions, and sixteen enzymes involved in the taxol pathway have been well characterized, including a novel taxane-10ß-hydroxylase (T10ßOH) and a newly putative ß-phenylalanyl-CoA ligase (PCL). Moreover, the source and formation of the taxane core and the details of the downstream synthetic pathway have been basically depicted, while the modification of the core taxane skeleton has not been fully reported, mainly concerning the developments from diol intermediates to 2-debenzoyltaxane. The acylation reaction mediated by specialized Taxus BAHD family acyltransferases (ACTs) is recognized as one of the most important steps in the modification of core taxane skeleton that contribute to the increase of taxol yield. Recently, the influence of acylation on the functional and structural diversity of taxanes has also been continuously revealed. This review summarizes the latest research advances of the taxol biosynthetic pathway and systematically discusses the acylation reactions supported by Taxus ACTs. The underlying mechanism could improve the understanding of taxol biosynthesis, and provide a theoretical basis for the mass production of taxol.

Carvedilol serves as a novel CYP1B1 inhibitor, a systematic drug repurposing approach through structure-based virtual screening and experimental verification.

Cytochrome P450 1B1 (CYP1B1) is a promising target for prevention and therapy of cancer, particularly those with drug resistance, stimulating cancer cell survival, and promoting cancer resistance. In view of the extreme complexity and high risk in drug discovery and development, a drug repurposing strategy was applied in the present study to find potential CYP1B1 inhibitors through structure-based virtual screening in the FDA database. Intriguingly, after a thorough assessment of docking scores, binding affinities, as well as binding modes, six compounds were highlighted for further verification. In fact, both carvedilol and indacaterol showed inhibitory activity towards human CYP1B1 with the IC50 of 1.11 µM and 59.52 µM, respectively, according to EROD assay; however, neither docking score nor the detailed binding mode of carvedilol in the hit pose dictated to be a superior CYP1B1 inhibitor to indacaterol, which called for the necessity to re-access the binding mode of carvedilol. Thus, the top two representative docking poses of carvedilol were re-assessed. Indeed, compared to the one hit in the virtual screening (due to a false positive Glide gscore), the other docking pose exhibited ideal performance in both molecular dynamics (MD) simulation, binding free energy, and density functional theory (DFT) calculation evaluations. This identification of the exact binding pose of carvedilol is not only essential for a better understanding of the mechanism underlying its activity, but also contributes to uncovering the structure-activity relationship of CYP1B1 inhibitors. Of note, carvedilol exhibited direct cytotoxicity against both human lung adenocarcinoma epithelial cell line A459 and its Taxol-resistant subline (A549/Taxol). In particular, it showed superior toxicity towards A549/Taxol cells that overexpressed CYP1B1, which further supported its potential to be an effective CYP1B1 inhibitor.

Metabolism-based herb-drug interaction of Corydalis Bungeanae Herba with berberine in vitro and in vivo in rats.

Corynoline (CRL) and berberine (BER) are the major bioactive components found in traditional Chinese medicines Corydalis Bungeanae Herba (Corydalis bungeanae) and Coptidis Rhizoma, respectively. The two herbs serve as anti-inflammatory agents and are generally applied to many prescriptions. The aims of the study were to evaluate herb-drug interaction of C. bungeanae with BER and to investigate the mechanisms of the interaction action. Pre-treatment of BER caused reduction of plasma CRL in rats with increased formation of its three oxidative metabolites (M1-M3). Compared with the vehicle-treated group, the peak concentration and area under the concentration-time curve of CRL decreased by ~60% (given CRL) and ~50% (given extracts) in rats pre-treated with BER, respectively, along with 130 and 100% increases in apparent clearance. More M1-M3 were formed in liver microsomes of rats pretreated with BER (7 days) than in those pretreated with vehicle. Additionally, elevated activities of rCYPs2D2 and 1A2 (CYPs2D6 and 1A2) were observed in the BER-induced group. Up-regulated expression of hepatic rCYP2D2 (CYP2D6) was found in animals after 7 days of treatment of BER. The study illustrated that C. Bungeanae and BER produced metabolic herb-drug interaction and provided important information that combination of C. bungeanae with BER-containing herbal medicines may encounter the risk of decreased efficacy of CRL.

Identification of chrysanthemum (Chrysanthemum morifolium) self-incompatibility.

There has been a heated argument over self-incompatibilityof chrysanthemum (Chrysanthemum morifolium) among chrysanthemum breeders. In order to solve the argument, we investigated pistil receptivity, seed set, and compatible index of 24 chrysanthemum cultivars. It was found that the 24 cultivars averagely had 3.7-36.3 pollen grains germinating on stigmas at 24 hours after self-pollination through the fluorescence microscope using aniline blue staining method. However, only 10 of them produced self-pollinated seeds, and their seed sets and compatible indexes were 0.03-56.50% and 0.04-87.50, respectively. The cultivar "Q10-33-1" had the highest seed set (56.50%) and compatible index (87.50), but ten of its progeny had a wide range of separation in seed set (0-37.23%) and compatible index (0-68.65). The results indicated that most of chrysanthemum cultivars were self-incompatible, while a small proportion of cultivars were self-compatible. In addition, there is a comprehensive separation of self-incompatibility among progeny from the same self-pollinated self-compatible chrysanthemum cultivar. Therefore, it is better to emasculate inflorescences during chrysanthemum hybridization breeding when no information concerning its self-incompatibility characteristics is available. However, if it is self-incompatible and propagated by vegetative methods, it is unnecessary to carry out emasculation when it is used as a female plant during hybridization breeding.

Oligomer procyanidins from grape seeds induce a paraptosis-like programmed cell death in human glioblastoma U-87 cells.

CONTEXT: We recently reported that F2, an oligomer procyanidin fraction isolated from grape seeds, triggered an original form of cell death in U-87 human glioblastoma cells with a phenotype resembling morphological characteristics of paraptosis. However, the specific death mode induced by F2 and the mechanism of its action have not been assessed so far. OBJECTIVE: In the present work, we therefore further investigated the death mode of human glioblastoma cells induced by F2 and gained insight into the nature of the signaling pathways activated by F2 in glioblastoma cells. MATERIALS AND METHODS: Cell viability assay using MTT, (AO/EB) double staining, Western blot analysis, and Ca2+ assay using fura-2. RESULTS: Morphology studies revealed extensive cytoplasmic vacuolization in dying cells and no apoptotic body formation, membrane bleb formation, or nuclear fragmentation, though some was accompanied by MAPK activation and new protein synthesis, and was independent of caspase activation. Moreover, we demonstrated the involvement of calcium mobilization in F2-induced U-87 cell signaling. DISCUSSION AND CONCLUSION: Altogether we showed that F2 induced a kind of cell death resembling paraptosis in U-87 cells. The current report complements previous studies on the characterization of F2-induced U-87 cell death, enhances our understanding of the action mechanism of F2 on glioma, and helps in the development of novel antitumor therapeutics.

Inhibition of U-87 human glioblastoma cell proliferation and formyl peptide receptor function by oligomer procyanidins (F2) isolated from grape seeds.

Gliomas are the most common and lethal tumor type in the brain. The present study investigated the effect of oligomer procyanidins (F2) (F2, degree of polymerization 2-15), a natural fraction isolated from grape seeds on the biological behavior of glioblastoma cells. We found that F2 significantly inhibited the glioblastoma growth, with little cytotoxicity on normal cells, induced G2/M arrest and decreased mitochondrial membrane potential in U-87 cells. It also induced a non-apoptotic cell death phenotype resembling paraptosis in U-87 cells. In addition, it was found for the first time that F2 in non-cytotoxic concentrations selectively inhibited U-87 cell chemotaxis mediated by a G-protein coupled receptor formyl peptide receptor FPR, which is implicated in tumor cell invasion and metastasis. Further experiments indicated that F2 inhibited fMLF-induced U-87 cell calcium mobilization and MAP kinases ERK1/2 phosphorylation. Moreover, F2 attenuated the glioblastoma FPR expression, a new molecular target for glioma therapeutics, which has been shown to play important roles in glioma cells chemotaxis, proliferation and angiogenesis in addition to its promotion to tumor progression, but did not affect FPR mRNA expression in U-87 cells. Taken together, our results suggest that F2 may be a promising candidate for the development of novel anti-tumor therapeutics.