Ji-Rong Yang, Chieh-Yu Cheng, Chih-Yuan Chen, Chao-Hua Lin, Chuan-Yi Kuo, Hsiang-Yi Huang, Fu-Ting Wu, Yu-Chih Yang, Chia-Ying Wu, Ming-Tsan Liu*, and Pei-Wen Hsiao* (2017) A virus-like particle vaccination strategy expands its tolerance to H3N2 antigenic drift by enhancing neutralizing antibodies against hemagglutinin stalk. Antiviral Research, 2017, 140: 62-75
Seasonal influenza viruses impact public health annually due to their continual evolution. However, the current inactivated seasonal vaccines provide poor protection against antigenically drifted viruses and require periodical reformulation through hit-and-miss predictions about which strains will circulate during the next season. To reduce the impact caused by vaccine mismatch, we investigated the drift-tolerance of virus-like particles (VLP) as an improved vaccine candidate. The cross-protective humoral immunity elicited by the H3N2-VLP vaccine constructed for the 2011-2012 season was examined against viruses isolated from 2010 to 2015 in Taiwan evolving chronologically through clades 1, 4, 5, 3B and 3C, as well as viruses that were circulating globally in 2005, 2007 and 2009. Mouse immunization results demonstrated that H3N2-VLP vaccine elicited superior immunological breadth in comparison with the cognate conventional whole-inactivated virus (WIV) vaccine. Titers of neutralizing antibodies against heterologous strains representing each epidemic period in the VLP group were significantly higher than in the WIV group, indicating the antibody repertoire induced by the H3N2-VLPs was insensitive to viral antigenic drift over a span of at least 10 years. Noticeably, H3N2-VLP elicited higher levels of anti-stalk antibodies than H3N2-WIV, which offset the ineffectiveness caused by antigenic drift. This advantageous effect was attributed to the uncleaved precursor of their HA proteins. These results suggest a mechanism through which VLP-induced humoral immunity may better tolerate the evolutionary dynamics of influenza viruses and point to the possible use of a VLP vaccine as a method by which the requirement for annual updates of seasonal influenza vaccines may be diminished.
Yu-Yi Wu, Bo-Han Hou, Wen-Chi Lee, Shin-Hua Lu, Chen-Jui Yang, Hervé Vaucheret and Ho-Ming Chen (2017) DCL2- and RDR6-dependent transitive silencing of SMXL4 and SMXL5 in Arabidopsis dcl4 mutants causes defective phloem transport and carbohydrate over-accumulation. The Plant Journal, 2017, 90(6):1064-1078
Dicer-Like (DCL) enzymes are able to process double-stranded RNA into small RNAs. Arabidopsis DCL4 and DCL2 each allow the post-transcriptional gene silencing (PTGS) of viruses and transgenes, but DCL2 activity is mostly obscured by DCL4. This hierarchy likely prevents DCL2 having any detrimental effects on endogenous genes. Indeed, dcl4 mutants exhibit leaf pigmentation under regular growth conditions. Here we report that the purple phenotype of dcl4 leaves correlates with carbohydrate over-accumulation and defective phloem transport, and depends on the activity of DCL2 and two enzymes, Suppressor of Gene Silencing 3 (SGS3) and RNA-Dependent RNA Polymerase 6 (RDR6), involved in double-stranded RNA synthesis. Further, this phenotype correlates with the down-regulation of two genes expressed in the apex and the vasculature, SMAX1-Like 4 (SMXL4) and SMXL5, and the accumulation of DCL2- and RDR6-dependent small interfering RNAs derived from these two genes. Supporting a causal effect, smxl4 smxl5 double mutants exhibit leaf pigmentation, enhanced starch accumulation and defective phloem transport, similar to dcl4 plants. Overall, this study elucidates the detrimental action of DCL2 when DCL4 is absent, and indicates that DCL4 outcompeting DCL2 in wild-type plants is crucial to prevent the degradation of endogenous transcripts by DCL2- and RDR6-dependent transitive PTGS.
Yang S-Y, Huang T-K, Kuo H-F, Chiou T-J (2017) Role of vacuoles in phosphorus storage and remobilization Journal of Experimental Botany: erw481
Vacuoles play a fundamental role in storage and remobilization of various nutrients, including phosphorus (P), an essential element for cell growth and development. Cells acquire P primarily in the form of inorganic orthophosphate (Pi). However, the form of P stored in vacuoles varies by organism and tissue. Algae and yeast store polyphosphates (polyPs), whereas plants store Pi and inositol phosphates (InsPs) in vegetative tissues and seeds, respectively. In this review, we summarize how vacuolar P molecules are stored and reallocated and how these processes are regulated and co-ordinated. The roles of SYG1/PHO81/XPR1 (SPX)-domain-containing membrane proteins in allocating vacuolar P are outlined. We also highlight the importance of vacuolar P in buffering the cytoplasmic Pi concentration to maintain cellular homeostasis when the external P supply fluctuates, and present additional roles for vacuolar polyP and InsP besides being a P reserve. Furthermore, we discuss the possibility of alternative pathways to recycle Pi from other P metabolites in vacuoles. Finally, future perspectives for researching this topic and its potential application in agriculture are proposed.
Yao-Pin Lin, Meng-Chen Wu, and Yee-yung Charng* (2016) Identification of Chlorophyll Dephytylase Involved in Chlorophyll Turnover.The Plant Cell, 2016, 28, 2974-2990
In photosynthesis, chlorophylls absorb light energy, which is transformed into chemical energy by the multi-protein-pigment complex called photosystem. The photosystem, composing of chlorophylls and proteins, tends to be damaged during the process of photosynthesis. The plant cells must repair the damaged photosystem to maintain the photosynthetic efficiency, causing the bound chlorophylls to turnover. Previous studies suggest that chlorophylls in damaged photosystem would be salvaged by two successive steps: 1. Dephytylation of chlorophylls; 2. Rephytylation of the dephytylated chlorophylls (or chlorophyllides). The latter is catalyzed by chlorophyll synthase, but the enzyme involved in the first reaction has been enigmatic. More than a century, chlorophyllase has been the only enzyme known to hydrolyze chlorophyll into chlorophyllide in vitro. However, the role of chlorophyllase in chlorophyll catabolism remains controversial. In an effort in cloning the mutant gene responsible for a heat sensitive phenotype in Arabidopsis, we identified a novel chloroplast protein capable of hydrolyzing chlorophylls and named it chlorophyll dephytylase1 (CLD1). The results from genetic and biochemical experiments suggested that CLD1 is involved in the first step of the chlorophyll salvage cycle. Plants lacking CLD1 significantly reduced the photosynthetic efficiency and viability under prolonged heat stress, underscoring the importance of the chlorophyll salvage cycle for plant thermotolerance. The discovery of CLD1 fills the gap in chlorophyll metabolism and facilitates further studies in the understanding of photosystem repair and its regulation.
Choun-Sea Lin, Jeremy JW Chen, Chi-Chou Chiu, Han C.W. Hsiao, Chen-Jui Yang, Xiao-Hua Jin, James Leebens-Mack, Claude W. dePamphilis ,Yao-Ting Huang, Ling-Hung Yang, Wan-Jung Chang, Ling Kui, Gane Ka-Shu Wong, Jer-Ming Hu, Wen Wang, Ming-Che Shih (2017) Concomitant loss of NDH complex-related genes within chloroplast and nuclear genomes in some orchids. The Plant Journal. DOI: 10.1111/tpj.13525
Chloroplast NAD(P)H dehydrogenase-like (NDH) complex consists of ~30 subunits from both the nuclear and chloroplast genomes and is ubiquitous across most land plants. In some orchids, such as Phalaenopsis equestris, Dendrobium officinale and D. catenatum, most of the 11 chloroplast genome encoded ndh genes (cp-ndh) have been lost. Here we investigated whether functional cp-ndh genes have been completely lost in these orchids or whether they have been transferred and retained in the nuclear genomes. Further, we assessed whether both cp-ndh genes and nucleus-encoded NDH-related genes can be lost resulting in the absence of the NDH complex. Comparative analyses of the genome of Apostasia odorata, an orchid species with a complete complement of cp-ndh genes which represents the sister lineage to all other orchids, and three published orchid genome sequences for Phalaenopsis equestris, D. officinale and D. catenatum which are all missing cp-ndh genes, indicated that copies of cp-ndh genes are not present in any of these four nuclear genomes. This observation suggests that the NDH complex is not necessary for some plants. Comparative genomic/transcriptomic analyses of currently available plastid genome sequences and nuclear transcriptome data showed that 47 out of 660 photoautotrophic plants and all the heterotrophic plants are missing plastid encoded cp-ndh genes and exhibit no evidence for maintenance of a functional NDH complex. Our data indicate that the NDH complex can be lost in photoautotrophic plant species. Further, the loss of the NDH complex may increase the probability of transition from a photoautotrophic to a heterotrophic life history.
Ya-Ting Chao, Shao-Hua Yen, Jen-Hau Yeh, Wan-Chieh Chen, Ming-Che Shih*(2017) Orchidstra 2.0—A Transcriptomics Resource for the Orchid Family Plant & Cell Physiol DOI:10.1093/pcp/pcw220
Orchidaceae, the orchid family, encompasses more than 25,000 species and five subfamilies. Due to their beautiful and exotic flowers, distinct biological and ecological features, orchids have aroused wide interest among both researchers and the general public. We constructed the Orchidstra database, a resource for orchid transcriptome assembly and gene annotations. The Orchistra database has been under active development since 2013. To accommodate the increasing amount of orchid transcriptome data and house more comprehensive information, Orchidstra 2.0 has been built with a new database system to store the annotations of 510,947 protein-coding genes and 161,826 noncoding transcripts, covering 18 orchid species belonging to 12 genera in five subfamilies of Orchidaceae. We have improved the N50 size of protein-coding genes, provided new functional annotations (including protein-coding gene annotations, protein domain/family information, pathways analysis, Gene Ontology term assignments, orthologous genes across orchid species, cross-links to the database of model species, and miRNA information), and improved the user interface with better website performance. We also provide new database functionalities for database searching and sequence retrieval. Moreover, the Orchidstra 2.0 database incorporates detailed RNA-Seq gene expression data from various tissues and developmental stages in different orchid species. The database will be useful for gene prediction and gene family studies, and for exploring gene expression in orchid species. The Orchidstra 2.0 database is freely accessible at http://orchidstra2.abrc.sinica.edu.tw.
Maria Karmella Apaya, Meng-Ting Chang, and Lie-Fen Shyur* (2016) Phytomedicine polypharmacology: Cancer therapy through modulating the tumor microenvironment and oxylipin dynamics.Pharmacology & Therapeutics 162:58-68
Integrative approaches in cancer therapy have recently been extended beyond the induction of cytotoxicity to controlling the tumor microenvironment and modulating inflammatory cascades and pathways such as lipid mediator biosynthesis and their dynamics. Profiling of important lipid messengers, such as oxylipins, produced as part of the physiological response to pharmacological stimuli, provides a unique opportunity to explore drug pharmacology and the possibilities for molecular management of cancer physiopathology. Whereas single targeted chemotherapeutic drugs commonly lack efficacy and invoke drug resistance and/or adverse effects in cancer patients, traditional herbal medicines are seen as bright prospects for treating complex diseases, such as cancers, in a systematic and holistic manner. Understanding the molecular mechanisms of traditional medicine and its bioactive chemical constituents may aid the modernization of herbal remedies and the discovery of novel phytoagents for cancer management. In this review, systems-based polypharmacology and studies to develop multi-target drugs or leads from phytomedicines and their derived natural products that may overcome the problems of current anti-cancer drugs, are proposed and summarized.
Kyoko Nakagawa-Goto*, Jo-Yu Chen, Yu-Ting Cheng, Wai-Leng Lee, Munehisa Takeya, Yohei Saito, Kuo-Hsiung Lee*, and Lie-Fen Shyur* (2016) Novel sesquiterpene lactone analogues as potent anti-breast cancer agents. Molecular Oncology, 2016, 10(6):921-937
Triple-negative breast cancer (TNBC) is associated with high grade, metastatic phenotype, younger patient age, and poor prognosis. The discovery of an effective anti-TNBC agent has been a challenge in oncology. In this study, fifty-eight ester derivatives (DETDs) with a novel sesquiterpene dilactone skeleton were organically synthesized from a bioactive natural product deoxyelephantopin (DET). Among them, DETD-35 showed potent antiproliferative activities against a panel of breast cancer cell lines including TNBC cell line MDA-MB-231, without inhibiting normal mammary cells M10. DETD-35 exhibited a better effect than parental DET on inhibiting migration, invasion, and motility of MDA-MB-231 cells in a concentration-dependent manner. Comparative study of DETD-35, DET and chemotherapeutic drug paclitaxel (PTX) showed that PTX mainly caused a typical time-dependent G2/M cell-cycle arrest, while DETD-35 or DET treatment induced cell apoptosis. In vivo efficacy of DETD-35 was evaluated using a lung metastatic MDA-MB-231 xenograft mouse model. DETD-35 significantly suppressed metastatic pulmonary foci information along with the expression level of VEGF and COX-2 in SCID mice. DETD-35 also showed a synergistic antitumor effect with PTX in vitro and in vivo. This study suggests that the novel compound DETD-35 may have a potential to be further developed into a therapeutic or adjuvant agent for chemotherapy against metastatic TNBC.
Jia-Hua Feng, Kyoko Nakagawa-Goto, Kuo-Hsiung Lee, and Lie-Fen Shyur* (2016) A novel plant sesquiterpene lactone derivative DETD-35 suppresses BRAFV600E mutant melanoma growth and overcomes acquired vemurafenib resistance in mice. Molecular Cancer Therapeutics, 15(6):1163-1176
Acquired resistance to vemurafenib (PLX4032), a chemotherapeutic drug targeting BRAFV600E mutant melanoma, is developed frequently through reactivation of RAF/MEK/ERK signaling or bypass mechanisms. Current combination therapy (e.g., MEK inhibitor plus vemurafenib) shows improvement in major clinical end points but percentage of patients with adverse toxic events are higher than vemurafenib monotherapy and most patients relapse ultimately. It is therefore an urgent need to develop new anti-melanoma drug and/or adjuvant agent for vemurafenib therapy. We created a novel semi-organically modified derivative DETD-35 from a plant sesquiterpene lactone deoxyelephantopin (DET), which showed potent effect against both parental human BRAFV600E mutant melanoma (A375) and vemurafenib resistance melanoma (A375-R) cell proliferation in vitro and no cytotoxicity to normal melanocyte. DETD-35 inhibited BRAFV600E mutant melanoma growth as effective as FDA approval drug vemurafenib and overcame both intrinsic and acquired vemurafenib resistance in mouse xenograft. Notably, the combination of DETD-35 and vemurafenib exhibited synergism and showed the most significant effects in both in vitro and xenograft mouse models compared to the monotherapy. Mechanistic studies revealed that DETD-35 triggered ROS-induced apoptotic cell death in both A375 and A375-R melanoma cells and overcamed acquired vemurafenib resistance through inhibition of the MEK-ERK, Akt, and STAT3 signaling pathways. Overall, our data suggest the great therapeutic or adjuvant potential of DETD-35 in management of melanoma patients with BRAFV600E mutation. The published article was selected as the “Highlights” of the issue in the journal “Molecular Cancer Therapeutics”; in addition, one ROC patent is issued and USA/PCT patents are pending.
H.-F. Chang, S.-L. Wang and K.-C. Yeh* (2017) Effect of gallium exposure in Arabidopsis thaliana is similar to aluminum stress. Environmental Science & Technology: Accepted DOI: 10.1021/acs.est.6b05760
The manuscript describes the first thorough exploration of gallium exposure in the model plant Arabidopsis. Gallium, a rare element, is one of the major elements in semiconductor compounds that are used in integrated circuits and optoelectronic devices. As one of major producers of semiconductor in the world, Hsinchu and Taichung Science Parks in Taiwan has been contaminated with gallium. The contamination of gallium in soil and water may lead to its uptake by plants and accumulation of gallium in the food chain. To our best knowledge, the harmful effects of gallium in plants are not yet investigated. Therefore, we investigated the accumulation, possible toxicity and defense systems of gallium exposure in plants. We found high similarities of exposure effects between gallium and aluminum. The Ga induced root secretion of citrate and malate play an important role for the protection from Ga toxicity.
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2017/08/21 10:30 AM
Dr. Chia-Lin Chung (Associate Professor, Department of Plant Pathology and Microbiology, National Taiwan University)
Bakanae of rice: new insights into an emerging old disease
Dr. Chung uses quantitative genetics approaches such as linkage mapping and genome-wide association mapping, in combined with molecular markers or whole-genome sequencing analysis, to dissect defense mechanisms against blast and bakanae disease in rice.
Auditorium A134, Agricultural Technology Building, Agricultural Biotechnology Research Center 2017/08/28 10:30 AM
Dr. Ho-Ming Chen (Assistant Research Fellow, Agricultural Biotechnology Research Center, Academia Sinica)
Toward RNA interference 2.0: new insights into the biogenesis, action, and movement of plant small RNA
Auditorium A134, Agricultural Technology Building, Agricultural Biotechnology Research Center