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1.
Nucleic Acids Res ; 46(22): 11712-11725, 2018 12 14.
Article in English | MEDLINE | ID: mdl-30239885

ABSTRACT

Plant immunity depends on massive expression of pathogenesis-related genes (PRs) whose transcription is de-repressed by pathogen-induced signals. Salicylic acid (SA) acts as a major signaling molecule in plant immunity and systemic acquired resistance triggered by bacterial or viral pathogens. SA signal results in the activation of the master immune regulator, Nonexpressor of pathogenesis-related genes 1 (NPR1), which is thought to be recruited by transcription factors such as TGAs to numerous downstream PRs. Despite its key role in SA-triggered immunity, the biochemical nature of the transcriptional coactivator function of NPR1 and the massive transcriptional reprogramming induced by it remain obscure. Here we demonstrate that the CBP/p300-family histone acetyltransferases, HACs and NPR1 are both essential to develop SA-triggered immunity and PR induction. Indeed HACs and NPR1 form a coactivator complex and are recruited to PR chromatin through TGAs upon SA signal, and finally the HAC-NPR1-TGA complex activates PR transcription by histone acetylation-mediated epigenetic reprogramming. Thus, our study reveals a molecular mechanism of NPR1-mediated transcriptional reprogramming and a key epigenetic aspect of the central immune system in plants.


Subject(s)
Arabidopsis Proteins/genetics , Arabidopsis/genetics , Basic-Leucine Zipper Transcription Factors/genetics , Gene Expression Regulation, Plant/drug effects , Histone Acetyltransferases/genetics , Salicylic Acid/pharmacology , Anti-Infective Agents/pharmacology , Arabidopsis/microbiology , Arabidopsis/virology , Arabidopsis Proteins/metabolism , Bacteria/immunology , Basic-Leucine Zipper Transcription Factors/metabolism , Histone Acetyltransferases/metabolism , Isonicotinic Acids/pharmacology , Multiprotein Complexes/genetics , Multiprotein Complexes/metabolism , Mutation , Plant Immunity/drug effects , Plant Immunity/genetics , Plant Proteins/genetics , Plant Proteins/metabolism , Plants, Genetically Modified , Salicylic Acid/chemistry , Transcriptome/drug effects , Viruses/immunology
2.
Plant J ; 71(1): 135-46, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22381007

ABSTRACT

To cope with a lifetime of exposure to a variety of pathogens, plants have developed exquisite and refined defense mechanisms that vary depending on the type of attacking pathogen. Defense-associated transcriptional reprogramming is a central part of plant defense mechanisms. Chromatin modification has recently been shown to be another layer of regulation for plant defense mechanisms. Here, we show that the RPD3/HDA1-class histone deacetylase HDA19 is involved in the repression of salicylic acid (SA)-mediated defense responses in Arabidopsis. Loss of HDA19 activity increased SA content and increased the expression of a group of genes required for accumulation of SA as well as pathogenesis related (PR) genes, resulting in enhanced resistance to Pseudomonas syringae. We found that HDA19 directly associates with and deacetylates histones at the PR1 and PR2 promoters. Thus, our study shows that HDA19, by modifying chromatin to a repressive state, ensures low basal expression of defense genes, such as PR1, under unchallenged conditions, as well as their proper induction without overstimulation during defense responses to pathogen attacks. Thus, the role of HDA19 might be critical in preventing unnecessary activation and self-destructive overstimulation of defense responses, allowing successful growth and development.


Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/immunology , Histone Deacetylases/metabolism , Salicylic Acid/metabolism , Arabidopsis/genetics , Arabidopsis/metabolism , Arabidopsis Proteins/genetics , Disease Resistance , Gene Expression Regulation, Plant , Histone Deacetylases/genetics , Mutagenesis, Insertional , Promoter Regions, Genetic , Pseudomonas syringae/pathogenicity , Signal Transduction
3.
Am J Chin Med ; 36(2): 399-410, 2008.
Article in English | MEDLINE | ID: mdl-18457369

ABSTRACT

Since TNF-related apoptosis inducing ligand (TRAIL) is one of several apoptotic stimuli on articular chondrocytes, the modulation of the mechanism mediated by TRAIL could be considered as a novel strategy for the treatment of osteoarthritis (OA). Previous studies demonstrated that Clematis mandshurica prevents staurosporin-induced apoptosis in articular chondrocytes. This study was undertaken to examine whether Clematis mandshurica could prevent TRAIL-induced apoptosis in articular chondrocytes. Our data show that Clematis mandshurica prevents adenoviral TRAIL (Ad-TRAIL)-induced apoptosis in primary cultured articular chondrocytes. Clematis mandshurica prevents Ad-TRAIL-induced down-regulation of 14-3-3 and phosphorylated Akt. In addition, Clematis mandshurica treatment prevents the Ad-TRAIL-induced reduction of the interactions between 14-3-3 with phospho-ser112-Bad and phospho-ser136-Bad, and BcL-xL with phospho-ser155-Bad. A better understanding of the mechanism underlying inhibition of apoptosis in OA chondrocytes by Clematis mandshurica might lead to the development of a new therapeutic strategy for OA.


Subject(s)
Apoptosis/drug effects , Chondrocytes/cytology , Clematis , Joints/cytology , Plant Extracts/pharmacology , TNF-Related Apoptosis-Inducing Ligand/antagonists & inhibitors , 14-3-3 Proteins/metabolism , Adenoviridae , Animals , Cells, Cultured , Depression, Chemical , Down-Regulation , Oncogene Protein v-akt/metabolism , Osteoarthritis/drug therapy , Osteoarthritis/etiology , Rats , Rats, Sprague-Dawley , TNF-Related Apoptosis-Inducing Ligand/pharmacology
4.
J Ethnopharmacol ; 111(2): 213-8, 2007 May 04.
Article in English | MEDLINE | ID: mdl-17174496

ABSTRACT

OBJECTIVE: To dissect the mechanism of the protection of staurosporin-induced apoptosis on rat chondrocytes by a purified extract from Clematis mandshurica. DESIGN: Primary cultured rat articular chondrocytes as well as RCJ3.1C.18 cells were incubated with 1 microM staurosporin and 300 microg/ml purified extract from Clematis mandshurica. Western blot assay, silencing 14-3-3 gene and immunoprecipitation were conducted. RESULTS: Clematis mandshurica prevented staurosporin-induced downregulation of several antiapoptotic bcl-2 family proteins Bcl-xL and Bcl-2, and staurosporin-induced upregulation of an apoptotic bcl-2 family protein Bax. Clematis mandshurica also prevented staurosporin-induced downregulation of a premitochondrial antiapoptotic protein 14-3-3. It is noticeable that siRNA to 14-3-3 abolished the prevention of caspase-3 activation by Clematis mandshurica. Furthermore viability assay corroborated that silencing of 14-3-3 gene abolished this apoptosis protection efficacy by Clematis mandshurica. Immunoprecipitation assay elucidated that Clematis mandshurica prevented the staurosporin-induced reduction of the interactions between 14-3-3 with phospho-ser112-Bad and Bcl-xL to phospho-ser155-Bad. CONCLUSIONS: Clematis mandshurica prevents staurosporin-induced apoptosis of rat chondrocytes via 14-3-3.


Subject(s)
14-3-3 Proteins/metabolism , Chondrocytes/drug effects , Clematis/chemistry , Plant Extracts/isolation & purification , Plant Extracts/pharmacology , Animals , Apoptosis/drug effects , Cartilage, Articular/cytology , Cell Culture Techniques , Cell Line, Transformed , Cell Survival/drug effects , Cells, Cultured , Chondrocytes/cytology , Down-Regulation/drug effects , Femur Head/cytology , Humerus/cytology , Rats , Rats, Sprague-Dawley , Staurosporine/pharmacology
5.
Arthritis Rheum ; 50(2): 534-42, 2004 Feb.
Article in English | MEDLINE | ID: mdl-14872496

ABSTRACT

OBJECTIVE: To investigate whether TRAIL influences the pathogenesis of osteoarthritis (OA). METHODS: A recombinant adenoviral vector system (Ad-TRAIL) was used. Expression of TRAIL in a rat chondrocyte cell line (RCJ3.1C.18) and alterations in the expression of death and decoy receptors after Ad-TRAIL infection were measured by Western blot assay. To explore the underlying mechanism, Western blot assays (to detect caspase 8, poly[ADP-ribose] polymerase [PARP], and caspase 3 activation), mitochondrial membrane potential (DeltaPsim) measurement, Hoechst staining, and DNA electrophoresis were conducted. Next, expression of TRAIL and death and decoy receptors was examined by immunochemistry in primary cultured chondrocytes and on cartilage obtained from rats with experimentally induced OA. RESULTS: Ad-TRAIL infection induced expression of TRAIL in RCJ3.1C.18 cells, increased expression of death receptor 4 (DR4), and decreased expression of DR5 and decoy receptor 1 (DcR1). Ad-TRAIL, at doses of 10 and 100 multiplicities of infection, decreased the viability of chondrocytes 4 days after infection. Reduction of DeltaPsim, cytochrome c release, nuclear condensation, activation of caspase 3 and PARP, and DNA fragmentation proved the induction of apoptosis. Activation of caspase 8 was also observed. Ad-TRAIL also induced apoptosis in primary cultured chondrocytes, in which alterations in expression of TRAIL and death receptors were similar to those observed in RCJ3.1C.18 cells. Cartilage obtained from rats with experimentally induced OA showed increased expression of TRAIL and DR4 and decreased expression of DR5 and DcR1 compared with control cartilage. CONCLUSION: TRAIL induces chondrocyte apoptosis, and TRAIL-induced chondrocyte apoptosis may play a role in the pathogenesis of OA.


Subject(s)
Apoptosis/drug effects , Chondrocytes/drug effects , Membrane Glycoproteins/pharmacology , Osteoarthritis, Knee/pathology , Tumor Necrosis Factor-alpha/pharmacology , Animals , Antibodies, Blocking/pharmacology , Apoptosis Regulatory Proteins , Cartilage, Articular/drug effects , Cartilage, Articular/metabolism , Cartilage, Articular/pathology , Cell Line, Transformed , Chondrocytes/metabolism , Chondrocytes/pathology , Disease Models, Animal , Dose-Response Relationship, Drug , Immunoenzyme Techniques , In Situ Nick-End Labeling , Male , Membrane Glycoproteins/metabolism , Membrane Potentials/drug effects , Mitochondria/drug effects , Mitochondria/physiology , Osteoarthritis, Knee/metabolism , Rats , Rats, Sprague-Dawley , TNF-Related Apoptosis-Inducing Ligand , Tumor Necrosis Factor-alpha/metabolism
6.
Biotechnol Lett ; 25(3): 213-8, 2003 Feb.
Article in English | MEDLINE | ID: mdl-12882573

ABSTRACT

Transgenic Nicotiana tabacum cell lines were developed expressing the human lactoferrin gene driven by the oxidative stress-inducible peroxidase (SWPA2) promoter. Western blot analysis showed the accumulation of both the full-length human lactoferrin protein as well as a immuno-reactive truncated fragment. Accumulation of human lactoferrin as monitored by ELISA increased proportionally to cell growth and reached a maximal (up to 4.3% of total soluble proteins) at the stationary phase of growth. Protein extracts from transgenic tobacco cells exhibited antibacterial activity.


Subject(s)
Lactoferrin/biosynthesis , Lactoferrin/genetics , Nicotiana/genetics , Nicotiana/metabolism , Anti-Bacterial Agents/pharmacology , Cells, Cultured , Escherichia coli/drug effects , Gene Expression Regulation , Humans , Lactoferrin/isolation & purification , Lactoferrin/pharmacology , Plants, Genetically Modified/genetics , Plants, Genetically Modified/metabolism , Quality Control , Recombinant Proteins/biosynthesis , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification , Recombinant Proteins/pharmacology , Salmonella typhimurium/drug effects , Staphylococcus aureus/drug effects
7.
J Plant Physiol ; 160(4): 347-53, 2003 Apr.
Article in English | MEDLINE | ID: mdl-12756914

ABSTRACT

To analyze the physiological role of dehydroascorbate reductase (DHAR, EC 1.8.5.1) catalyzing the reduction of DHA to ascorbate in environmental stress adaptation, T1 transgenic tobacco (Nicotiana tabacum cv. Xanthi) plants expressing a human DHAR gene in chloroplasts were biochemically characterized and tested for responses to various stresses. Fully expanded leaves of transgenic plants had about 2.29 times higher DHAR activity (units/g fresh wt) than non-transgenic (NT) plants. Interestingly, transgenic plants also showed a 1.43 times higher glutathione reductase activity than NT plants. As a result, the ratio of AsA/DHA was changed from 0.21 to 0.48, even though total ascorbate content was not significantly changed. When tobacco leaf discs were subjected to methyl viologen (MV) at 5 mumol/L and hydrogen peroxide (H2O2) at 200 mmol/L, transgenic plants showed about a 40% and 25% reduction in membrane damage relative to NT plants, respectively. Furthermore, transgenic seedlings showed enhanced tolerance to low temperature (15 degrees C) and NaCl (100 mmol/L) compared to NT plants. These results suggest that a human derived DHAR properly works for the protection against oxidative stress in plants.


Subject(s)
Adaptation, Physiological , Nicotiana/genetics , Oxidoreductases/genetics , Plants, Genetically Modified/genetics , Cold Temperature , Humans , Hydrogen Peroxide/pharmacology , Paraquat/pharmacology , Plant Leaves/drug effects , Plants, Genetically Modified/metabolism , Plants, Genetically Modified/physiology , Sodium Chloride/administration & dosage , Nicotiana/metabolism , Nicotiana/physiology
8.
Planta Med ; 69(11): 1005-8, 2003 Nov.
Article in English | MEDLINE | ID: mdl-14735437

ABSTRACT

In order to produce a human lactoferrin (hLf) protein in cultured plant cells, we developed Korean ginseng (Panax ginseng) cell line using an oxidative stress-inducible peroxidase (SWPA2) promoter and characterized the production of human lactoferrin in cultured cells. A construct containing a targeting signal peptide from tobacco endoplasmic reticulum fused to human lactoferrin cDNA under the control of SWPA2 promoter was engineered. Transgenic Korean ginseng cell lines that produced a recombinant hLf protein were successfully generated and confirmed by PCR and Southern blot analyses. Western blot and ELISA analyses showed that hLf protein was synthesized in the transgenic cells. The production of hLf showed a maximal level (up to 3.0% of total soluble protein) in the stationary phase of callus cultures. These results suggest that the transgenic cell lines in this study will be biotechnologically useful for the commercial production of hLf protein in cell cultures, with no need for purification.


Subject(s)
Lactoferrin/biosynthesis , Lactoferrin/genetics , Nicotiana/genetics , Nicotiana/metabolism , Panax , Phytotherapy , Cells, Cultured , Humans , Plants, Genetically Modified/genetics , Plants, Genetically Modified/metabolism , Recombinant Proteins/biosynthesis , Recombinant Proteins/genetics
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