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Yu YH, Zhao XH. Longan Polysaccharides with Covalent Selenylation Combat the Fumonisin B1-Induced Cell Toxicity and Barrier Disruption in Intestinal Epithelial (IEC-6) Cells. Nutrients 2023; 15:4679. [PMID: 37960333 PMCID: PMC10650868 DOI: 10.3390/nu15214679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/25/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023] Open
Abstract
In this study, the soluble, but non-digestible, longan (Dimocarpus longan Lour.) polysaccharides (LP) were extracted from dried longan fruits and then chemically selenylated to produce two selenylated products, namely SeLP1 and SeLP2, with different selenylation extents. The aim was to investigate their protective effects on rat intestinal epithelial (IEC-6) cells exposed to the food toxin fumonisin B1 (FB1). LP only contained total Se content of less than 0.01 g/kg, while SeLP1 and SeLP2 were measured with respective total Se content of up to 1.46 and 4.79 g/kg. The cell viability results showed that these two selenylated products were more efficient than LP in the IEC-6 cells in alleviating FB1-induced cell toxicity, suppressing lactate dehydrogenase (LDH) release, and decreasing the generation of intracellular reactive oxygen species (ROS). These two selenylated products were also more effective than LP in combating FB1-induced barrier disruption via increasing the transepithelial electric resistance (TEER), reducing the paracellular permeability, decreasing the mitochondrial membrane potential (MMP) loss, and maintaining cell barrier integrity by upregulating the tight-junction-related genes and proteins. FB1 caused cell oxidative stress and barrier dysfunction by activating the MAPK and mitochondrial apoptosis signaling pathways, while SeLP1 and SeLP2 could regulate the tMAPK- and apoptosis-related proteins to suppress the FB1-mediated activation of the two pathways. Overall, SeLP2 was observed to be more active than SeLP1 in the IEC-6 cells. In conclusion, the chemical selenylation of LP caused an activity enhancement to ameliorate the FB1-induced cell cytotoxicity and intestinal barrier disruption. Meanwhile, the increased selenylation of LP would endow the selenylated product SeLP2 with more activity.
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Affiliation(s)
- Ya-Hui Yu
- School of Biology and Food Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China
- Research Centre of Food Nutrition and Human Healthcare, Guangdong University of Petrochemical Technology, Maoming 525000, China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong University of Petrochemical Technology, Maoming 525000, China
| | - Xin-Huai Zhao
- School of Biology and Food Engineering, Guangdong University of Petrochemical Technology, Maoming 525000, China
- Research Centre of Food Nutrition and Human Healthcare, Guangdong University of Petrochemical Technology, Maoming 525000, China
- Maoming Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong University of Petrochemical Technology, Maoming 525000, China
- College of Food Science, Northeast Agricultural University, Harbin 150030, China
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Zhao Y, Liu Z, Wang L, Liu H. Fumonisin B1 as a Tool to Explore Sphingolipid Roles in Arabidopsis Primary Root Development. Int J Mol Sci 2022; 23:12925. [PMID: 36361715 PMCID: PMC9654530 DOI: 10.3390/ijms232112925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/19/2022] [Accepted: 10/21/2022] [Indexed: 03/28/2024] Open
Abstract
Fumonisin B1 is a mycotoxin that is structurally analogous to sphinganine and sphingosine and inhibits the biosynthesis of complex sphingolipids by repressing ceramide synthase. Based on the connection between FB1 and sphingolipid metabolism, FB1 has been widely used as a tool to explore the multiple functions of sphingolipids in mammalian and plant cells. The aim of this work was to determine the effect of sphingolipids on primary root development by exposing Arabidopsis (Arabidopsis thaliana) seedlings to FB1. We show that FB1 decreases the expression levels of several PIN-FORMED (PIN) genes and the key stem cell niche (SCN)-defining transcription factor genes WUSCHEL-LIKE HOMEOBOX5 (WOX5) and PLETHORAs (PLTs), resulting in the loss of quiescent center (QC) identity and SCN maintenance, as well as stunted root growth. In addition, FB1 induces cell death at the root apical meristem in a non-cell-type-specific manner. We propose that sphingolipids play a key role in primary root growth through the maintenance of the root SCN and the amelioration of cell death in Arabidopsis.
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Affiliation(s)
- Yanxue Zhao
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475000, China
| | - Zhongjie Liu
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China
| | - Lei Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475000, China
| | - Hao Liu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng 475000, China
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Wang L, Suo X, Liu Y, Liu C, Luo M. Sphingosine Promotes Embryo Biomass in Upland Cotton: A Biochemical and Transcriptomic Analysis. Biomolecules 2021; 11:525. [PMID: 33915924 PMCID: PMC8065874 DOI: 10.3390/biom11040525] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/24/2021] [Accepted: 03/29/2021] [Indexed: 12/21/2022] Open
Abstract
Sphingolipids are essential membrane components and signal molecules, but their regulatory role in cotton embryo growth is largely unclear. In this study, we evaluated the effects of treatment with the sphingolipid synthesis inhibitor fumonisin B1 (FB1), the serine palmityl transferase (SPT) inhibitor myriocin, the SPT sphingolipid product DHS (d18:0 dihydrosphingosine), and the post-hydroxylation DHS product PHS (t18:0 phytosphingosine) on embryo growth in culture, and performed comparative transcriptomic analysis on control and PHS-treated samples. We found that FB1 could inhibit cotton embryo development. At the five-day ovule/embryo developmental stage, PHS was the most abundant sphingolipid. An SPT enzyme inhibitor reduced the fresh weight of embryos, while PHS had the opposite effect. The transcriptomic analysis identified 2769 differentially expressed genes (1983 upregulated and 786 downregulated) in the PHS samples. A large number of transcription factors were highly upregulated, such as zinc finger, MYB, NAC, bHLH, WRKY, MADS, and GRF in PHS-treated samples compared to controls. The lipid metabolism and plant hormone (auxin, brassinosteroid, and zeatin) related genes were also altered. Our findings provide target metabolites and genes for cotton seed improvement.
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Affiliation(s)
- Li Wang
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou 450001, China; (L.W.); (Y.L.); (C.L.)
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Xiaodong Suo
- Key Laboratory of Biotechnology and Crop Quality Improvement of Ministry of Agriculture, Biotechnology Research Center, Southwest University, Chongqing 400716, China;
| | - Yujie Liu
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou 450001, China; (L.W.); (Y.L.); (C.L.)
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Chen Liu
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou 450001, China; (L.W.); (Y.L.); (C.L.)
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China
| | - Ming Luo
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, Zhengzhou 450001, China; (L.W.); (Y.L.); (C.L.)
- Key Laboratory of Biotechnology and Crop Quality Improvement of Ministry of Agriculture, Biotechnology Research Center, Southwest University, Chongqing 400716, China;
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Poh WH, Lin J, Colley B, Müller N, Goh BC, Schleheck D, El Sahili A, Marquardt A, Liang Y, Kjelleberg S, Lescar J, Rice SA, Klebensberger J. The SiaABC threonine phosphorylation pathway controls biofilm formation in response to carbon availability in Pseudomonas aeruginosa. PLoS One 2020; 15:e0241019. [PMID: 33156827 PMCID: PMC7647112 DOI: 10.1371/journal.pone.0241019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/06/2020] [Indexed: 12/17/2022] Open
Abstract
The critical role of bacterial biofilms in chronic human infections calls for novel anti-biofilm strategies targeting the regulation of biofilm development. However, the regulation of biofilm development is very complex and can include multiple, highly interconnected signal transduction/response pathways, which are incompletely understood. We demonstrated previously that in the opportunistic, human pathogen P. aeruginosa, the PP2C-like protein phosphatase SiaA and the di-guanylate cyclase SiaD control the formation of macroscopic cellular aggregates, a type of suspended biofilms, in response to surfactant stress. In this study, we demonstrate that the SiaABC proteins represent a signal response pathway that functions through a partner switch mechanism to control biofilm formation. We also demonstrate that SiaABCD functionality is dependent on carbon substrate availability for a variety of substrates, and that upon carbon starvation, SiaB mutants show impaired dispersal, in particular with the primary fermentation product ethanol. This suggests that carbon availability is at least one of the key environmental cues integrated by the SiaABCD system. Further, our biochemical, physiological and crystallographic data reveals that the phosphatase SiaA and its kinase counterpart SiaB balance the phosphorylation status of their target protein SiaC at threonine 68 (T68). Crystallographic analysis of the SiaA-PP2C domain shows that SiaA is present as a dimer. Dynamic modelling of SiaA with SiaC suggested that SiaA interacts strongly with phosphorylated SiaC and dissociates rapidly upon dephosphorylation of SiaC. Further, we show that the known phosphatase inhibitor fumonisin inhibits SiaA mediated phosphatase activity in vitro. In conclusion, the present work improves our understanding of how P. aeuruginosa integrates specific environmental conditions, such as carbon availability and surfactant stress, to regulate cellular aggregation and biofilm formation. With the biochemical and structural characterization of SiaA, initial data on the catalytic inhibition of SiaA, and the interaction between SiaA and SiaC, our study identifies promising targets for the development of biofilm-interference drugs to combat infections of this aggressive opportunistic pathogen.
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Affiliation(s)
- Wee-Han Poh
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jianqing Lin
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
- Singapore Immunology Network (SIgN), Agency for Science, Technology and Research, Singapore, Singapore
| | - Brendan Colley
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Nicolai Müller
- Konstanz Research School Chemical Biology, Departments of Chemistry and Biology, University of Konstanz, Konstanz, Germany
| | - Boon Chong Goh
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - David Schleheck
- Konstanz Research School Chemical Biology, Departments of Chemistry and Biology, University of Konstanz, Konstanz, Germany
| | - Abbas El Sahili
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
- The School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Andreas Marquardt
- Konstanz Research School Chemical Biology, Departments of Chemistry and Biology, University of Konstanz, Konstanz, Germany
| | - Yang Liang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- The School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
- The School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Julien Lescar
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore
- The School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Scott A. Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- The School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- The ithree Institute, The University of Technology Sydney, Sydney, Australia
| | - Janosch Klebensberger
- University of Stuttgart, Institute of Biochemistry and Technical Biochemistry, Stuttgart, Germany
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Zavafer A, González-Solís A, Palacios-Bahena S, Saucedo-García M, Tapia de Aquino C, Vázquez-Santana S, King-Díaz B, Gavilanes-Ruiz M. Organized Disassembly of Photosynthesis During Programmed Cell Death Mediated By Long Chain Bases. Sci Rep 2020; 10:10360. [PMID: 32587330 PMCID: PMC7316715 DOI: 10.1038/s41598-020-65186-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 04/27/2020] [Indexed: 11/09/2022] Open
Abstract
In plants, pathogen triggered programmed cell death (PCD) is frequently mediated by polar lipid molecules referred as long chain bases (LCBs) or ceramides. PCD interceded by LCBs is a well-organized process where several cell organelles play important roles. In fact, light-dependent reactions in the chloroplast have been proposed as major players during PCD, however, the functional aspects of the chloroplast during PCD are largely unknown. For this reason, we investigated events that lead to disassembly of the chloroplast during PCD mediated by LCBs. To do so, LCB elevation was induced with Pseudomonas syringae pv. tomato (a non-host pathogen) or Fumonisin B1 in Phaseolus vulgaris. Then, we performed biochemical tests to detect PCD triggering events (phytosphingosine rises, MPK activation and H2O2 generation) followed by chloroplast structural and functional tests. Observations of the chloroplast, via optical phenotyping methods combined with microscopy, indicated that the loss of photosynthetic linear electron transport coincides with the organized ultrastructure disassembly. In addition, structural changes occurred in parallel with accumulation of H2O2 inside the chloroplast. These features revealed the collapse of chloroplast integrity and function as a mechanism leading to the irreversible execution of the PCD promoted by LCBs.
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Affiliation(s)
- Alonso Zavafer
- Climate Change Cluster, University of Technology Sydney, Faculty of Science Building 4, Level 6 Corner of Thomas and, Harris St, Ultimo NSW 2007, Sydney, Australia
| | - Ariadna González-Solís
- Dpto. de Bioquímica, Facultad de Química, Conjunto E. Universidad Nacional Autónoma de México (UNAM). Ciudad Universitaria, 04510, Ciudad de México, México
| | - Silvia Palacios-Bahena
- Dpto. de Bioquímica, Facultad de Química, Conjunto E. Universidad Nacional Autónoma de México (UNAM). Ciudad Universitaria, 04510, Ciudad de México, México
| | - Mariana Saucedo-García
- Instituto de Ciencias Agropecuarias, Universidad Autónoma del Estado de Hidalgo, Tulancingo, Hidalgo, México
| | - Cinthya Tapia de Aquino
- Dpto. de Bioquímica, Facultad de Química, Conjunto E. Universidad Nacional Autónoma de México (UNAM). Ciudad Universitaria, 04510, Ciudad de México, México
| | - Sonia Vázquez-Santana
- Dpto. de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México (UNAM). Ciudad Universitaria, 04510, Ciudad de México, México
| | - Beatriz King-Díaz
- Dpto. de Bioquímica, Facultad de Química, Conjunto E. Universidad Nacional Autónoma de México (UNAM). Ciudad Universitaria, 04510, Ciudad de México, México
| | - Marina Gavilanes-Ruiz
- Dpto. de Bioquímica, Facultad de Química, Conjunto E. Universidad Nacional Autónoma de México (UNAM). Ciudad Universitaria, 04510, Ciudad de México, México.
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6
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Riley RT, Merrill AH. Ceramide synthase inhibition by fumonisins: a perfect storm of perturbed sphingolipid metabolism, signaling, and disease. J Lipid Res 2019; 60:1183-1189. [PMID: 31048407 PMCID: PMC6602133 DOI: 10.1194/jlr.s093815] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 04/25/2019] [Indexed: 01/18/2023] Open
Abstract
Fumonisins are mycotoxins that cause diseases of plants and, when consumed by animals, can damage liver, kidney, lung, brain, and other organs, alter immune function, and cause developmental defects and cancer. They structurally resemble sphingolipids (SLs), and studies nearly 30 years ago discovered that the most prevalent fumonisin [fumonisin B1 (FB1)] potently inhibits ceramide synthases (CerSs), enzymes that use fatty acyl-CoAs to N-acylate sphinganine (Sa), sphingosine (So), and other sphingoid bases. CerS inhibition by FB1 triggers a "perfect storm" of perturbations in structural and signaling SLs that include: reduced formation of dihydroceramides, ceramides, and complex SLs; elevated Sa and So and their 1-phosphates, novel 1-deoxy-sphingoid bases; and alteration of additional lipid metabolites from interrelated pathways. Moreover, because the initial enzyme of sphingoid base biosynthesis remains active (sometimes with increased activity), the impact is multiplied by the continued production of damaging metabolites. Evidence from many studies, including characterization of knockout mice for specific CerSs and analyses of human blood (which found that FB1 intake is associated with elevated Sa 1-phosphate), has consistently pointed to CerS as the proximate target of FB1 It is also apparent that the changes in multiple bioactive lipids and related biologic processes account for the ensuing spectrum of animal and plant disease. Thus, the diseases caused by fumonisins can be categorized as "sphingolipidoses" (in these cases, due to defective SL biosynthesis), and the lessons learned about the consequences of CerS inhibition should be borne in mind when contemplating other naturally occurring and synthetic compounds (and genetic manipulations) that interfere with SL metabolism.
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Affiliation(s)
- Ronald T Riley
- College of Public Health, Department of Environmental Health Science, University of Georgia, Athens, GA 30602
| | - Alfred H Merrill
- School of Biological Sciences and the Parker H. Petit Institute for Bioengineering and Bioscience Georgia Institute of Technology, Atlanta, GA 30332
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Glenz R, Schmalhaus D, Krischke M, Mueller MJ, Waller F. Elevated Levels of Phosphorylated Sphingobases Do Not Antagonize Sphingobase- or Fumonisin B1-Induced Plant Cell Death. Plant Cell Physiol 2019; 60:1109-1119. [PMID: 30796453 DOI: 10.1093/pcp/pcz033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 02/08/2019] [Indexed: 05/25/2023]
Abstract
Long-chain bases (LCBs), also termed sphingobases, are building blocks of sphingolipids, which make up a significant proportion of the cellular membrane system. They are also bioactive molecules regulating intracellular processes. Elevated levels of LCBs like phytosphingosine and dihydrosphingosine can induce cell death in plants and correlate with programmed cell death (PCD) reactions after pathogen recognition. We investigated the previously hypothesized antagonism between phosphorylated and nonphosphorylated LCBs with respect to cell death in Arabidopsis thaliana. Using HPLC-MS/MS, we determined levels of phosphorylated and nonphosphorylated LCBs after cell death induction by LCB application or by Fumonisin B1 (FB1) treatment. We show that previously reported antagonistic effects of phosphorylated LCBs after simultaneous application with nonphosphorylated LCBs are linked to reduced uptake of nonphosphorylated LCBs into the tissue. Furthermore, phosphorylated LCBs did not antagonize PCD induced by avirulence protein recognition. In a functional approach, we used Arabidopsis lines with perturbed levels of phosphorylated LCBs. In these plants, the degree of FB1-induced cell death did not consistently correlate negatively with levels of phosphorylated LCBs, but positively with levels of major nonphosphorylated LCBs phytosphingosine and dihydrosphingosine. As treatment with phosphorylated LCBs did not antagonize cell death, and elevated in vivo levels of these LCB species did not reduce FB1-induced cell death, we conclude that the hypothesized general cell death-antagonizing effect of phosphorylated LCBs in plant cell death reactions should be rejected. Instead, our time-course analysis of LCB levels during cell death reactions showed a positive correlation between levels of nonphosphorylated LCBs and cell death.
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Affiliation(s)
- Renï Glenz
- Pharmaceutical Biology, Julius-von-Sachs Institute of Biosciences, Biocenter, Julius-Maximilians-Universit�t W�rzburg, Julius-von-Sachs-Platz 2, D-97082 W�rzburg, Germany
| | - Dorette Schmalhaus
- Pharmaceutical Biology, Julius-von-Sachs Institute of Biosciences, Biocenter, Julius-Maximilians-Universit�t W�rzburg, Julius-von-Sachs-Platz 2, D-97082 W�rzburg, Germany
| | - Markus Krischke
- Pharmaceutical Biology, Julius-von-Sachs Institute of Biosciences, Biocenter, Julius-Maximilians-Universit�t W�rzburg, Julius-von-Sachs-Platz 2, D-97082 W�rzburg, Germany
| | - Martin J Mueller
- Pharmaceutical Biology, Julius-von-Sachs Institute of Biosciences, Biocenter, Julius-Maximilians-Universit�t W�rzburg, Julius-von-Sachs-Platz 2, D-97082 W�rzburg, Germany
| | - Frank Waller
- Pharmaceutical Biology, Julius-von-Sachs Institute of Biosciences, Biocenter, Julius-Maximilians-Universit�t W�rzburg, Julius-von-Sachs-Platz 2, D-97082 W�rzburg, Germany
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8
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Qin X, Zhang RX, Ge S, Zhou T, Liang YK. Sphingosine kinase AtSPHK1 functions in fumonisin B1-triggered cell death in Arabidopsis. Plant Physiol Biochem 2017; 119:70-80. [PMID: 28846870 DOI: 10.1016/j.plaphy.2017.08.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/01/2017] [Accepted: 08/11/2017] [Indexed: 05/12/2023]
Abstract
The fungal toxin Fumonisin B1 (FB1) is a strong inducer to trigger plant hypersensitive responses (HR) along with increased long chain bases (LCB) and long chain base phosphates (LCBP) contents, though the regulatory mechanism of FB1 action and how the LCB/LCBP signalling cassette functions during the process is still not fully understood. Here, we report sphingosine kinase 1 (SPHK1) as a key factor in FB1-induced HR by modulating the salicylic acid (SA) pathway and reactive oxygen species (ROS) accumulation in Arabidopsis thaliana. Overexpression of SPHK1 increases the FB1-induced accumulations of ROS and SA. The double mutant that simultaneously overexpresses SPHK1 and suppresses the SPPASE or DPL1, two enzymes are mainly responsible for Phyto-sphingosine-1-phosphate (Phyto-S1P) removal, showed enhanced susceptibility to FB1 killing and FB1-induced SA activation than the plants overexpress SPHK1 alone. Exogenous sphingosine-1-phosphate (S1P) can modulate the transcription of the SA-responsive marker gene PR1 in a concentration-dependent biphasic manner. Suppression of SPHK1 decreases SA production whereas promotes jasmonic acid (JA) biosynthesis in response to FB1 applications. Our findings indicate a role of SPHK1 in modulating FB1-triggered cell death via SA and JA pathway interactions.
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Affiliation(s)
- Xiaoya Qin
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ruo-Xi Zhang
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Shengchao Ge
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Tao Zhou
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yun-Kuan Liang
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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9
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Yanagawa D, Ishikawa T, Imai H. Synthesis and degradation of long-chain base phosphates affect fumonisin B 1-induced cell death in Arabidopsis thaliana. J Plant Res 2017; 130:571-585. [PMID: 28303405 DOI: 10.1007/s10265-017-0923-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 12/07/2016] [Indexed: 05/12/2023]
Abstract
Fumonisin B1 (FB1), an inducer of cell death, disrupts sphingolipid metabolism; large accumulations of de novo synthesized free long-chain bases (LCBs) are observed. However, it remains unclear whether tolerance to FB1 toxicity in plants is connected with preventing the accumulation of free LCBs through their phosphorylation. Here a workflow for the extraction, detection and quantification of LCB phosphates (LCBPs) in Arabidopsis thaliana was developed. We studied the effect of expression of genes for three enzymes involved in the synthesis and degradation of LCBPs, LCB kinase (LCBK1), LCBP phosphatase (SPP1) and lyase (DPL1) on FB1-induced cell death. As expected, large accumulations of saturated free LCBs, dihydrosphingosine and phytosphingosine, were observed in the FB1-treated leaves. On the other hand, a high level of sphingenine phosphate was found in the FB1-treated leaves even though free sphingenine was found in low amounts in these leaves. In comparison of WT and spp1 plants, the LCBP/LCB ratio is likely to be correlated with the degree of FB1-induced cell death determined by trypan blue staining. The FB1-treated leaves in dpl1 plants showed severe cell death and the elevation of free LCBs and LCBPs. LCBK1-OX and -KD plants showed resistance and sensitivity to FB1, respectively, whereas free LCB and LCBP levels in FB1-treated LCBK1-OX and -KD plants were moderately different to those in FB1-treated WT plants. Overall, the findings described here suggest that LCBP/LCB homeostasis is an important topic that participates in the tolerance of plant cells to FB1.
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Affiliation(s)
- Daiki Yanagawa
- Department of Biology, Graduate School of Natural Science, Konan University, Kobe, 658-8501, Japan
- The Institute for Integrative Neurobiology, Konan University, Kobe, 658-8501, Japan
| | - Toshiki Ishikawa
- Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570, Japan
| | - Hiroyuki Imai
- Department of Biology, Graduate School of Natural Science, Konan University, Kobe, 658-8501, Japan.
- The Institute for Integrative Neurobiology, Konan University, Kobe, 658-8501, Japan.
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Shaheen HM, Onoda A, Shinkai Y, Nakamura M, El-Ghoneimy AA, El-Sayed YS, Takeda K, Umezawa M. The ceramide inhibitor fumonisin B1 mitigates the pulmonary effects of low-dose diesel exhaust inhalation in mice. Ecotoxicol Environ Saf 2016; 132:390-396. [PMID: 27376354 DOI: 10.1016/j.ecoenv.2016.06.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/15/2016] [Accepted: 06/17/2016] [Indexed: 06/06/2023]
Abstract
Recent studies have suggested that inhalation of diesel exhaust (DE), a major source of air pollution, results in pulmonary alterations; however, the effects of DE at low concentrations are poorly understood. Therefore, this study was conducted to elucidate the pulmonary effects of low-level exposure to DE and the potential role of a ceramide de novo biosynthesis inhibitor, fumonisin B1 (FB1) to ameliorate the DE-toxicity. Male C57BL/6J mice underwent 1- or 7-day experiments (4 equal groups/experiment) and were assigned to the control, DE (0.1mg/m(3)), FB1 (6.75mg/kg body weight SC at days 0, 3 and 6) or DE+FB1 groups. DE and/or FB1 treatment had no effect on the expression of Nos2, a biomarker of oxidative stress. Ceramide production in the bronchial epithelial cells and Sphk1 mRNA expression were induced in the lung after the 7-day DE exposure and were partially suppressed by the FB1 treatment. Additionally, the effects of DE on SP-A and SP-D mRNA expression were also suppressed by the FB1 treatment. These results suggest that ceramide and Sphk1 may be sensitive biomarkers for low-level DE-induced pulmonary effects. Collectively, ceramide likely contributes to the DE-induced early stage of airway inflammation, which is considered a potential pulmonary target during low-level DE exposure.
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Affiliation(s)
- Hazem M Shaheen
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, Japan; Department of Pharmacology, Faculty of Veterinary Medicine, Damanhour University, Egypt.
| | - Atsuto Onoda
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, Japan; Department of Hygienic Chemistry, Graduate School of Pharmaceutical Sciences, Tokyo University of Science, Japan; Research Fellow of Japan Society for the Promotion of Science, Japan.
| | - Yusuke Shinkai
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, Japan.
| | - Masayuki Nakamura
- Department of Hygienic Chemistry, Graduate School of Pharmaceutical Sciences, Tokyo University of Science, Japan.
| | - Ashraf A El-Ghoneimy
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, Japan; Department of Pharmacology, Faculty of Veterinary Medicine, South Valley University, Egypt.
| | - Yasser S El-Sayed
- Department of Veterinary Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, Damanhour University, Egypt.
| | - Ken Takeda
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, Japan.
| | - Masakazu Umezawa
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, Japan.
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11
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Blacutt AA, Mitchell TR, Bacon CW, Gold SE. Bacillus mojavensis RRC101 Lipopeptides Provoke Physiological and Metabolic Changes During Antagonism Against Fusarium verticilliodes. Mol Plant Microbe Interact 2016. [PMID: 29775248 DOI: 10.1094/mpmi-05-16-0093-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The mycotoxigenic pathogen Fusarium verticillioides threatens the quality and utility of maize across industrial and agricultural purposes. Chemical control is complicated by the intimate endophytic lifestyle of the pathogen with its host. Bacillus mojavensis RRC101, a maize-endophytic bacterium, has been observed to reduce F. verticillioides disease severity and fumonisin accumulation when coinoculated to maize. Genome sequencing and annotation identified a number of biocontrol-relevant pathways in RRC101. Biochemical assays confirmed the presence and activity of surfactin- and fengycin-type lipopeptides, with fengycins responsible for antifungal activity against F. verticillioides. This antagonism manifests as inhibition of filamentous growth, with microscopy revealing hyphal distortions, vacuolization, and lysis. F. verticillioides secondary metabolism also responds to antagonism, with lipopeptide challenge inducing greater fumonisin production and, in the case of fengycins, eliciting pigment accumulation at sites of inhibition. Together, these data suggest that antibiotic and toxin production are components of a complex biochemical interaction among maize endophytes, one pathogenic and one beneficial.
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12
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Riedel S, Abel S, Burger HM, van der Westhuizen L, Swanevelder S, Gelderblom WCA. Differential modulation of the lipid metabolism as a model for cellular resistance to fumonisin B1-induced cytotoxic effects in vitro. Prostaglandins Leukot Essent Fatty Acids 2016; 109:39-51. [PMID: 27269712 DOI: 10.1016/j.plefa.2016.04.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 04/21/2016] [Accepted: 04/21/2016] [Indexed: 12/30/2022]
Abstract
Differential sensitivity of primary hepatocytes and Chang cells to the cancer promoter fumonisin B1 (FB1)-induced cytotoxic effects were investigated in relation to changes in membrane lipid distribution. In contrast to primary hepatocytes, Chang cells were resistant to FB1-induced cytotoxic effects. This was associated with a high cholesterol (Chol) and sphingomyelin (SM) and low phosphatidylcholine (PC) content, resulting in a significant (P<0.05) decrease in phosphatidylethanolamine (PE)/PC ratio, increased Chol/total phosphoglyceride (TPG) ratios and low total polyunsaturated fatty acids (PUFA) content in PC and PE, suggesting a more rigid membrane structure. High levels of C18:1 and reduced polyunsaturated fatty acid (PUFA) levels are likely to provide selective resistance to FB1-induced oxidative stress. FB1-associated lipid changes included decreases in SM and Chol, increases in sphinganine (Sa) and PE with the increases in key saturated, monounsaturated, and PUFAs in PE as key role players in the differential responses to FB1-induced cell growth responses in cells.
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Affiliation(s)
- S Riedel
- Biomedical Research and Innovation Platform, South African Medical Research Council, PO Box 19070, Tygerberg 7505, South Africa.
| | - S Abel
- Mycotoxicology and Chemoprevention Research Group, Institute of Biomedical and Microbial Biotechnology, Cape Peninsula University of Technology, PO Box 1906, Bellville 7535, South Africa.
| | - H-M Burger
- Mycotoxicology and Chemoprevention Research Group, Institute of Biomedical and Microbial Biotechnology, Cape Peninsula University of Technology, PO Box 1906, Bellville 7535, South Africa.
| | - L van der Westhuizen
- Oxidative Stress Research Centre, Institute of Biomedical and Microbial Biotechnology, Cape Peninsula University of Technology, PO Box 1906, Bellville 7535, South Africa.
| | - S Swanevelder
- Biostatistics Unit, South African Medical Research Council, PO Box 19070, Tygerberg, South Africa.
| | - W C A Gelderblom
- Mycotoxicology and Chemoprevention Research Group, Institute of Biomedical and Microbial Biotechnology, Cape Peninsula University of Technology, PO Box 1906, Bellville 7535, South Africa; Department of Biochemistry, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa.
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13
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Arias SL, Mary VS, Otaiza SN, Wunderlin DA, Rubinstein HR, Theumer MG. Toxin distribution and sphingoid base imbalances in Fusarium verticillioides-infected and fumonisin B1-watered maize seedlings. Phytochemistry 2016; 125:54-64. [PMID: 26903312 DOI: 10.1016/j.phytochem.2016.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 11/30/2015] [Accepted: 02/09/2016] [Indexed: 05/12/2023]
Abstract
Fusarium verticillioides is a major maize pathogen and there are susceptible and resistant cultivars to this fungal infection. Recent studies suggest that its main mycotoxin fumonisin B1 (FB1) may be involved in phytopathogenicity, but the underlying mechanisms are mostly still unknown. This work was aimed at assessing whether FB1 disseminates inside the plants, as well as identifying possible correlations between the maize resistant/susceptible phenotype and the unbalances of the FB1-structurally-related sphingoid base sphinganine (Sa) and phytosphingosine (Pso) due to toxin accumulation. Resistant (RH) and susceptible hybrid (SH) maize seedlings grown from seeds inoculated with a FB1-producer F. verticillioides and from uninoculated ones irrigated with FB1 (20 ppm), were harvested at 7, 14 and 21 days after planting (dap), and the FB1, Sa and Pso levels were quantified in roots and aerial parts. The toxin was detected in roots and aerial parts for inoculated and FB1-irrigated plants of both hybrids. However, FB1 levels were overall higher in SH seedlings regardless of the treatment (infection or watering). Sa levels increased substantially in RH lines, peaking at 54-fold in infected roots at 14 dap. In contrast, the main change observed in SH seedlings was an increase of Pso in infected roots at 7 dap. Here, it was found that FB1 disseminates inside seedlings in the absence of FB1-producer fungal infections, perhaps indicating this might condition the fungus-plant interaction before the first contact. Furthermore, the results strongly suggest the existence of at least two ceramide synthase isoforms in maize with different substrate specificities, whose differential expression after FB1 exposure could be closely related to the susceptibility/resistance to F. verticillioides.
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Affiliation(s)
- Silvina L Arias
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI, UNC-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina
| | - Verónica S Mary
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI, UNC-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina
| | - Santiago N Otaiza
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI, UNC-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina
| | - Daniel A Wunderlin
- Instituto de Ciencia y Tecnología de Alimentos Córdoba (ICYTAC, UNC-CONICET), Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina
| | - Héctor R Rubinstein
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI, UNC-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina
| | - Martín G Theumer
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI, UNC-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina.
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14
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Antonissen G, Van Immerseel F, Pasmans F, Ducatelle R, Janssens GPJ, De Baere S, Mountzouris KC, Su S, Wong EA, De Meulenaer B, Verlinden M, Devreese M, Haesebrouck F, Novak B, Dohnal I, Martel A, Croubels S. Mycotoxins Deoxynivalenol and Fumonisins Alter the Extrinsic Component of Intestinal Barrier in Broiler Chickens. J Agric Food Chem 2015; 63:10846-10855. [PMID: 26632976 DOI: 10.1021/acs.jafc.5b04119] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Deoxynivalenol (DON) and fumonisins (FBs) are secondary metabolites produced by Fusarium fungi that frequently contaminate broiler feed. The aim of this study was to investigate the impact of DON and/or FBs on the intestinal barrier in broiler chickens, more specifically on the mucus layer and antioxidative response to oxidative stress. One-day-old broiler chicks were divided into four groups, each consisting of eight pens of seven birds each, and were fed for 15 days either a control diet, a DON-contaminated diet (4.6 mg DON/kg feed), a FBs-contaminated diet (25.4 mg FB1 + FB2/kg feed), or a DON+FBs-contaminated diet (4.3 mg DON and 22.9 mg FB1 + FB2/kg feed). DON and FBs affected the duodenal mucus layer by suppressing intestinal mucin (MUC) 2 gene expression and altering the mucin monosaccharide composition. Both mycotoxins decreased gene expression of the intestinal zinc transporter (ZnT)-1 and regulated intracellular methionine homeostasis, which are both important for preserving the cell's critical antioxidant activity. Feeding a DON- and/or FBs-contaminated diet, at concentrations close to the European Union maximum guidance levels (5 mg DON and 20 mg FB1 + FB2/kg feed) changes the intestinal mucus layer and several intestinal epithelial antioxidative mechanisms.
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Affiliation(s)
- Gunther Antonissen
- Department of Pharmacology, Toxicology and Biochemistry, Faculty of Veterinary Medicine, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Filip Van Immerseel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Richard Ducatelle
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Geert P J Janssens
- Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University , Heidestraat 19, 9820 Merelbeke, Belgium
| | - Siegrid De Baere
- Department of Pharmacology, Toxicology and Biochemistry, Faculty of Veterinary Medicine, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Konstantinos C Mountzouris
- Department of Nutritional Physiology and Feeding, Agricultural University of Athens , Iera Odos 75, 11855 Athens, Greece
| | - Shengchen Su
- Department of Animal and Poultry Sciences, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Eric A Wong
- Department of Animal and Poultry Sciences, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Bruno De Meulenaer
- Department of Food Safety and Food Quality (Partner in Food2Know), Faculty of Bioscience Engineering, Ghent University , Coupure Links 653, 9000 Gent, Belgium
| | - Marc Verlinden
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Mathias Devreese
- Department of Pharmacology, Toxicology and Biochemistry, Faculty of Veterinary Medicine, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Freddy Haesebrouck
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Barbara Novak
- Biomin Research Center , Technopark 1, 3430 Tulln, Austria
| | - Ilse Dohnal
- Biomin Research Center , Technopark 1, 3430 Tulln, Austria
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Siska Croubels
- Department of Pharmacology, Toxicology and Biochemistry, Faculty of Veterinary Medicine, Ghent University , Salisburylaan 133, 9820 Merelbeke, Belgium
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15
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Zhang X, Wu Q, Cui S, Ren J, Qian W, Yang Y, He S, Chu J, Sun X, Yan C, Yu X, An C. Hijacking of the jasmonate pathway by the mycotoxin fumonisin B1 (FB1) to initiate programmed cell death in Arabidopsis is modulated by RGLG3 and RGLG4. J Exp Bot 2015; 66:2709-21. [PMID: 25788731 PMCID: PMC4986873 DOI: 10.1093/jxb/erv068] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The mycotoxin fumonisin B1 (FB1) is a strong inducer of programmed cell death (PCD) in plants, but its underlying mechanism remains unclear. Here, we describe two ubiquitin ligases, RING DOMAIN LIGASE3 (RGLG3) and RGLG4, which control FB1-triggered PCD by modulating the jasmonate (JA) signalling pathway in Arabidopsis thaliana. RGLG3 and RGLG4 transcription was sensitive to FB1. Arabidopsis FB1 sensitivity was suppressed by loss of function of RGLG3 and RGLG4 and was increased by their overexpression. Thus RGLG3 and RGLG4 have coordinated and positive roles in FB1-elicited PCD. Mutated JA perception by coi1 disrupted the RGLG3- and RGLG4-related response to FB1 and interfered with their roles in cell death. Although FB1 induced JA-responsive defence genes, it repressed growth-related, as well as JA biosynthesis-related, genes. Consistently, FB1 application reduced JA content in wild-type plants. Furthermore, exogenously applied salicylic acid additively suppressed JA signalling with FB1 treatment, suggesting that FB1-induced salicylic acid inhibits the JA pathway during this process. All of these effects were attenuated in rglg3 rglg4 plants. Altogether, these data suggest that the JA pathway is hijacked by the toxin FB1 to elicit PCD, which is coordinated by Arabidopsis RGLG3 and RGLG4.
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Affiliation(s)
- Xu Zhang
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Qian Wu
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Shao Cui
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Jiao Ren
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Wanqiang Qian
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China Present address: Basic Research Service, Ministry of Science and Technology of the People's Republic of China, 15B, Fuxing Road, Beijing 100862, China
| | - Yang Yang
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China Present address: Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA
| | - Shanping He
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China Present address: Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, CA 90089, USA
| | - Jinfang Chu
- National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaohong Sun
- National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Cunyu Yan
- National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiangchun Yu
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
| | - Chengcai An
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing 100871, China
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16
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Zhao Y, Wang J, Liu Y, Miao H, Cai C, Shao Z, Guo R, Sun B, Jia C, Zhang L, Gigolashvili T, Wang Q. Classic myrosinase-dependent degradation of indole glucosinolate attenuates fumonisin B1-induced programmed cell death in Arabidopsis. Plant J 2015; 81:920-33. [PMID: 25645692 DOI: 10.1111/tpj.12778] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 01/12/2015] [Accepted: 01/20/2015] [Indexed: 05/08/2023]
Abstract
The mycotoxin fumonisin B1 (FB1) causes the accumulation of reactive oxygen species (ROS) which then leads to programmed cell death (PCD) in Arabidopsis. In the process of studying FB1-induced biosynthesis of glucosinolates, we found that indole glucosinolate (IGS) is involved in attenuating FB1-induced PCD. Treatment with FB1 elevates the expression of genes related to the biosynthesis of camalexin and IGS. Mutants deficient in aliphatic glucosinolate (AGS) or camalexin biosynthesis display similar lesions to Col-0 upon FB1 infiltration; however, the cyp79B2 cyp79B3 double mutant, which lacks induction of both IGS and camalexin, displays more severe lesions. Based on the fact that the classic myrosinase β-thioglucoside glucohydrolase (TGG)-deficient double mutant tgg1 tgg2, rather than atypical myrosinase-deficient mutant pen2-2, is more sensitive to FB1 than Col-0, and the elevated expression of TGG1, but not of PEN2, correlates with the decrease in IGS, we conclude that TGG-dependent IGS hydrolysis is involved in FB1-induced PCD. Indole-3-acetonitrile (IAN) and indole-3-carbinol (I3C), the common derivatives of IGS, were used in feeding experiments, and this rescued the severe cell death phenotype, which is associated with reduced accumulation of ROS as well as increased activity of antioxidant enzymes and ROS-scavenging ability. Despite the involvement of indole-3-acetic acid (IAA) in restricting FB1-induced PCD, feeding of IAN and I3C attenuated FB1-induced PCD in the IAA receptor mutant tir1-1 just as in Col-0. Taken together, our results indicate that TGG-catalyzed breakdown products of IGS decrease the accumulation of ROS by their antioxidant behavior, and attenuate FB1 induced PCD in an IAA-independent way.
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Affiliation(s)
- Yanting Zhao
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Department of Horticulture, Ministry of Agriculture, Zhejiang University, Hangzhou, 310058, China
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17
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Boppana NB, Stochaj U, Kodiha M, Bielawska A, Bielawski J, Pierce JS, Korbelik M, Separovic D. C6-pyridinium ceramide sensitizes SCC17B human head and neck squamous cell carcinoma cells to photodynamic therapy. J Photochem Photobiol B 2015; 143:163-8. [PMID: 25635908 DOI: 10.1016/j.jphotobiol.2015.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/02/2015] [Accepted: 01/03/2015] [Indexed: 11/17/2022]
Abstract
Combining photodynamic therapy (PDT) with another anticancer treatment modality is an important strategy for improved efficacy. PDT with Pc4, a silicon phthalocyanine photosensitizer, was combined with C6-pyridinium ceramide (LCL29) to determine their potential to promote death of SCC17B human head and neck squamous cell carcinoma cells. PDT+LCL29-induced enhanced cell death was inhibited by zVAD-fmk, a pan-caspase inhibitor, and fumonisin B1 (FB), a ceramide synthase inhibitor. Quantitative confocal microscopy showed that combining PDT with LCL29 enhanced FB-sensitive ceramide accumulation in the mitochondria. Furthermore, PDT+LCL29 induced enhanced FB-sensitive redistribution of cytochrome c and caspase-3 activation. Overall, the data indicate that PDT+LCL29 enhanced cell death via FB-sensitive, mitochondrial ceramide accumulation and apoptosis.
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Affiliation(s)
- Nithin B Boppana
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Ave., Detroit, MI 48201, USA
| | - Ursula Stochaj
- Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1YC, Canada
| | - Mohamed Kodiha
- Department of Physiology, McGill University, 3655 Promenade Sir William Osler, Montreal, QC H3G 1YC, Canada
| | - Alicja Bielawska
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Ave., Charleston, SC 29425, USA
| | - Jacek Bielawski
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Ave., Charleston, SC 29425, USA
| | - Jason S Pierce
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Ave., Charleston, SC 29425, USA
| | - Mladen Korbelik
- British Columbia Cancer Agency, 675 West 10th Ave., Vancouver, BC V5Z 1L3, Canada
| | - Duska Separovic
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, 259 Mack Ave., Detroit, MI 48201, USA; Karmanos Cancer Institute, Wayne State University, 4100 John R, Detroit, MI 48201, USA.
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18
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Kimberlin AN, Majumder S, Han G, Chen M, Cahoon RE, Stone JM, Dunn TM, Cahoon EB. Arabidopsis 56-amino acid serine palmitoyltransferase-interacting proteins stimulate sphingolipid synthesis, are essential, and affect mycotoxin sensitivity. Plant Cell 2013. [PMID: 24214397 DOI: 10.2307/23598494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Maintenance of sphingolipid homeostasis is critical for cell growth and programmed cell death (PCD). Serine palmitoyltransferase (SPT), composed of LCB1 and LCB2 subunits, catalyzes the primary regulatory point for sphingolipid synthesis. Small subunits of SPT (ssSPT) that strongly stimulate SPT activity have been identified in mammals, but the role of ssSPT in eukaryotic cells is unclear. Candidate Arabidopsis thaliana ssSPTs, ssSPTa and ssSPTb, were identified and characterized. Expression of these 56-amino acid polypeptides in a Saccharomyces cerevisiae SPT null mutant stimulated SPT activity from the Arabidopsis LCB1/LCB2 heterodimer by >100-fold through physical interaction with LCB1/LCB2. ssSPTa transcripts were more enriched in all organs and >400-fold more abundant in pollen than ssSPTb transcripts. Accordingly, homozygous ssSPTa T-DNA mutants were not recoverable, and 50% nonviable pollen was detected in heterozygous ssspta mutants. Pollen viability was recovered by expression of wild-type ssSPTa or ssSPTb under control of the ssSPTa promoter, indicating ssSPTa and ssSPTb functional redundancy. SPT activity and sensitivity to the PCD-inducing mycotoxin fumonisin B1 (FB1) were increased by ssSPTa overexpression. Conversely, SPT activity and FB1 sensitivity were reduced in ssSPTa RNA interference lines. These results demonstrate that ssSPTs are essential for male gametophytes, are important for FB1 sensitivity, and limit sphingolipid synthesis in planta.
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Affiliation(s)
- Athen N Kimberlin
- Center for Plant Science Inovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
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19
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Kimberlin AN, Majumder S, Han G, Chen M, Cahoon RE, Stone JM, Dunn TM, Cahoon EB. Arabidopsis 56-amino acid serine palmitoyltransferase-interacting proteins stimulate sphingolipid synthesis, are essential, and affect mycotoxin sensitivity. Plant Cell 2013; 25:4627-39. [PMID: 24214397 PMCID: PMC3875740 DOI: 10.1105/tpc.113.116145] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Maintenance of sphingolipid homeostasis is critical for cell growth and programmed cell death (PCD). Serine palmitoyltransferase (SPT), composed of LCB1 and LCB2 subunits, catalyzes the primary regulatory point for sphingolipid synthesis. Small subunits of SPT (ssSPT) that strongly stimulate SPT activity have been identified in mammals, but the role of ssSPT in eukaryotic cells is unclear. Candidate Arabidopsis thaliana ssSPTs, ssSPTa and ssSPTb, were identified and characterized. Expression of these 56-amino acid polypeptides in a Saccharomyces cerevisiae SPT null mutant stimulated SPT activity from the Arabidopsis LCB1/LCB2 heterodimer by >100-fold through physical interaction with LCB1/LCB2. ssSPTa transcripts were more enriched in all organs and >400-fold more abundant in pollen than ssSPTb transcripts. Accordingly, homozygous ssSPTa T-DNA mutants were not recoverable, and 50% nonviable pollen was detected in heterozygous ssspta mutants. Pollen viability was recovered by expression of wild-type ssSPTa or ssSPTb under control of the ssSPTa promoter, indicating ssSPTa and ssSPTb functional redundancy. SPT activity and sensitivity to the PCD-inducing mycotoxin fumonisin B1 (FB1) were increased by ssSPTa overexpression. Conversely, SPT activity and FB1 sensitivity were reduced in ssSPTa RNA interference lines. These results demonstrate that ssSPTs are essential for male gametophytes, are important for FB1 sensitivity, and limit sphingolipid synthesis in planta.
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Affiliation(s)
- Athen N. Kimberlin
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Saurav Majumder
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Gongshe Han
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Ming Chen
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Rebecca E. Cahoon
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Julie M. Stone
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Teresa M. Dunn
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Edgar B. Cahoon
- Center for Plant Science Innovation and Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
- Address correspondence to
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Agostini F, Dotti CG, Pérez-Cañamás A, Ledesma MD, Benetti F, Legname G. Prion protein accumulation in lipid rafts of mouse aging brain. PLoS One 2013; 8:e74244. [PMID: 24040215 PMCID: PMC3769255 DOI: 10.1371/journal.pone.0074244] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 07/31/2013] [Indexed: 12/20/2022] Open
Abstract
The cellular form of the prion protein (PrPC) is a normal constituent of neuronal cell membranes. The protein misfolding causes rare neurodegenerative disorders known as transmissible spongiform encephalopathies or prion diseases. These maladies can be sporadic, genetic or infectious. Sporadic prion diseases are the most common form mainly affecting aging people. In this work, we investigate the biochemical environment in which sporadic prion diseases may develop, focusing our attention on the cell membrane of neurons in the aging brain. It is well established that with aging the ratio between the most abundant lipid components of rafts undergoes a major change: while cholesterol decreases, sphingomyelin content rises. Our results indicate that the aging process modifies the compartmentalization of PrPC. In old mice, this change favors PrPC accumulation in detergent-resistant membranes, particularly in hippocampi. To confirm the relationship between lipid content changes and PrPC translocation into detergent-resistant membranes (DRMs), we looked at PrPC compartmentalization in hippocampi from acid sphingomyelinase (ASM) knockout (KO) mice and synaptosomes enriched in sphingomyelin. In the presence of high sphingomyelin content, we observed a significant increase of PrPC in DRMS. This process is not due to higher levels of total protein and it could, in turn, favor the onset of sporadic prion diseases during aging as it increases the PrP intermolecular contacts into lipid rafts. We observed that lowering sphingomyelin in scrapie-infected cells by using fumonisin B1 led to a 50% decrease in protease-resistant PrP formation. This may suggest an involvement of PrP lipid environment in prion formation and consequently it may play a role in the onset or development of sporadic forms of prion diseases.
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Affiliation(s)
- Federica Agostini
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
- Department of Human Genetics, K.U., Leuven, Leuven, Belgium
| | - Carlos G. Dotti
- Department of Molecular and Developmental Genetics, VIB Center for the Biology of Disease, K.U., Leuven, Leuven, Belgium
- Department of Human Genetics, K.U., Leuven, Leuven, Belgium
| | | | | | - Federico Benetti
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
- Italian Institute of Technology, Trieste, Italy
- ELETTRA Laboratory, Sincrotrone Trieste S.C.p.A, AREA Science Park, Basovizza, Trieste, Italy
- * E-mail:
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21
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Yao J, Bi HE, Sheng Y, Cheng LB, Wendu RL, Wang CH, Cao GF, Jiang Q. Ultraviolet (UV) and hydrogen peroxide activate ceramide-ER stress-AMPK signaling axis to promote retinal pigment epithelium (RPE) cell apoptosis. Int J Mol Sci 2013; 14:10355-68. [PMID: 23685869 PMCID: PMC3676843 DOI: 10.3390/ijms140510355] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Revised: 04/15/2013] [Accepted: 05/02/2013] [Indexed: 12/25/2022] Open
Abstract
Ultraviolet (UV) radiation and reactive oxygen species (ROS) impair the physiological functions of retinal pigment epithelium (RPE) cells by inducing cell apoptosis, which is the main cause of age-related macular degeneration (AMD). The mechanism by which UV/ROS induces RPE cell death is not fully addressed. Here, we observed the activation of a ceramide-endoplasmic reticulum (ER) stress-AMP activated protein kinase (AMPK) signaling axis in UV and hydrogen peroxide (H2O2)-treated RPE cells. UV and H2O2 induced an early ceramide production, profound ER stress and AMPK activation. Pharmacological inhibitors against ER stress (salubrinal), ceramide production (fumonisin B1) and AMPK activation (compound C) suppressed UV- and H2O2-induced RPE cell apoptosis. Conversely, cell permeable short-chain C6 ceramide and AMPK activator AICAR (5-amino-1-β-D-ribofuranosyl-imidazole-4-carboxamide) mimicked UV and H2O2’s effects and promoted RPE cell apoptosis. Together, these results suggest that UV/H2O2 activates the ceramide-ER stress-AMPK signaling axis to promote RPE cell apoptosis.
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Affiliation(s)
- Jin Yao
- The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029, China; E-Mails: (H.-E.B.); (Y.S.); (L.-B.C.); (R.-L.W.); (C.-H.W.); (G.-F.C.)
- Authors to whom correspondence should be addressed: E-Mails: (J.Y.); (Q.J.); Tel./Fax: +86-025-8667-7699 (J.Y. & Q.J.)
| | - Hui-E Bi
- The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029, China; E-Mails: (H.-E.B.); (Y.S.); (L.-B.C.); (R.-L.W.); (C.-H.W.); (G.-F.C.)
| | - Yi Sheng
- The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029, China; E-Mails: (H.-E.B.); (Y.S.); (L.-B.C.); (R.-L.W.); (C.-H.W.); (G.-F.C.)
| | - Li-Bo Cheng
- The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029, China; E-Mails: (H.-E.B.); (Y.S.); (L.-B.C.); (R.-L.W.); (C.-H.W.); (G.-F.C.)
- Eye Department, Li-Yang City Hospital of Traditional Chinese Medicine, Li-Yang City 213300, China
| | - Ri-Le Wendu
- The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029, China; E-Mails: (H.-E.B.); (Y.S.); (L.-B.C.); (R.-L.W.); (C.-H.W.); (G.-F.C.)
| | - Cheng-Hu Wang
- The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029, China; E-Mails: (H.-E.B.); (Y.S.); (L.-B.C.); (R.-L.W.); (C.-H.W.); (G.-F.C.)
| | - Guo-Fan Cao
- The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029, China; E-Mails: (H.-E.B.); (Y.S.); (L.-B.C.); (R.-L.W.); (C.-H.W.); (G.-F.C.)
| | - Qin Jiang
- The Affiliated Eye Hospital of Nanjing Medical University, Nanjing 210029, China; E-Mails: (H.-E.B.); (Y.S.); (L.-B.C.); (R.-L.W.); (C.-H.W.); (G.-F.C.)
- Authors to whom correspondence should be addressed: E-Mails: (J.Y.); (Q.J.); Tel./Fax: +86-025-8667-7699 (J.Y. & Q.J.)
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Igarashi D, Bethke G, Xu Y, Tsuda K, Glazebrook J, Katagiri F. Pattern-triggered immunity suppresses programmed cell death triggered by fumonisin b1. PLoS One 2013; 8:e60769. [PMID: 23560104 PMCID: PMC3613394 DOI: 10.1371/journal.pone.0060769] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 03/02/2013] [Indexed: 12/22/2022] Open
Abstract
Programmed cell death (PCD) is a crucial process for plant innate immunity and development. In plant innate immunity, PCD is believed to prevent the spread of pathogens from the infection site. Although proper control of PCD is important for plant fitness, we have limited understanding of the molecular mechanisms regulating plant PCD. Plant innate immunity triggered by recognition of effectors (effector-triggered immunity, ETI) is often associated with PCD. However pattern-triggered immunity (PTI), which is triggered by recognition of elicitors called microbe-associated molecular patterns (MAMPs), is not. Therefore we hypothesized that PTI might suppress PCD. Here we report that PCD triggered by the mycotoxin fumonisin B1 (FB1) can be suppressed by PTI in Arabidopsis. FB1-triggered cell death was suppressed by treatment with the MAMPs flg22 (a part of bacterial flagellin) or elf18 (a part of the bacterial elongation factor EF-Tu) but not chitin (a component of fungal cell walls). Although plant hormone signaling is associated with PCD and PTI, both FB1-triggered cell death and suppression of cell death by flg22 treatment were still observed in mutants deficient in jasmonic acid (JA), ethylene (ET) and salicylic acid (SA) signaling. The MAP kinases MPK3 and MPK6 are transiently activated and inactivated within one hour during PTI. We found that FB1 activated MPK3 and MPK6 about 36–48 hours after treatment. Interestingly, this late activation was attenuated by flg22 treatment. These results suggest that PTI suppression of FB1-triggered cell death may involve suppression of MPK3/MPK6 signaling but does not require JA/ET/SA signaling.
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Affiliation(s)
- Daisuke Igarashi
- Department of Plant Biology, Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota, United States of America
- Institute for Innovation, Ajinomoto Co., Inc., Kawasaki-ku, Kawasaki, Japan
| | - Gerit Bethke
- Department of Plant Biology, Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Yuan Xu
- Department of Plant Biology, Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Kenichi Tsuda
- Department of Plant Biology, Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Jane Glazebrook
- Department of Plant Biology, Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota, United States of America
| | - Fumiaki Katagiri
- Department of Plant Biology, Microbial and Plant Genomics Institute, University of Minnesota, St. Paul, Minnesota, United States of America
- * E-mail:
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23
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Aflaki E, Doddapattar P, Radović B, Povoden S, Kolb D, Vujić N, Wegscheider M, Koefeler H, Hornemann T, Graier WF, Malli R, Madeo F, Kratky D. C16 ceramide is crucial for triacylglycerol-induced apoptosis in macrophages. Cell Death Dis 2012; 3:e280. [PMID: 22419109 PMCID: PMC3317349 DOI: 10.1038/cddis.2012.17] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/02/2012] [Accepted: 02/07/2012] [Indexed: 12/12/2022]
Abstract
Triacylglycerol (TG) accumulation caused by adipose triglyceride lipase (ATGL) deficiency or very low-density lipoprotein (VLDL) loading of wild-type (Wt) macrophages results in mitochondrial-mediated apoptosis. This phenotype is correlated to depletion of Ca(2+) from the endoplasmic reticulum (ER), an event known to induce the unfolded protein response (UPR). Here, we show that ER stress in TG-rich macrophages activates the UPR, resulting in increased abundance of the chaperone GRP78/BiP, the induction of pancreatic ER kinase-like ER kinase, phosphorylation and activation of eukaryotic translation initiation factor 2A, the translocation of activating transcription factor (ATF)4 and ATF6 to the nucleus and the induction of the cell death executor CCAAT/enhancer-binding protein homologous protein. C16:0 ceramide concentrations were increased in Atgl-/- and VLDL-loaded Wt macrophages. Overexpression of ceramide synthases was sufficient to induce mitochondrial apoptosis in Wt macrophages. In accordance, inhibition of ceramide synthases in Atgl-/- macrophages by fumonisin B1 (FB1) resulted in specific inhibition of C16:0 ceramide, whereas intracellular TG concentrations remained high. Although the UPR was still activated in Atgl-/- macrophages, FB1 treatment rescued Atgl-/- macrophages from mitochondrial dysfunction and programmed cell death. We conclude that C16:0 ceramide elicits apoptosis in Atgl-/- macrophages by activation of the mitochondrial apoptosis pathway.
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Affiliation(s)
- E Aflaki
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
- National Human Genome Research Institute/NIH Molecular Neurogenetics Section, 35 Convent Drive, Bethesda, MD, USA
| | - P Doddapattar
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - B Radović
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - S Povoden
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - D Kolb
- Institute of Cell Biology, Histology and Embryology, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
- Center for Medical Research, Medical University of Graz, Stiftingtalstrasse 24, 8010 Graz, Austria
| | - N Vujić
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - M Wegscheider
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - H Koefeler
- Institute of Cell Biology, Histology and Embryology, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - T Hornemann
- Institute of Clinical Chemistry, University of Zurich, Rämistrasse 100, 8091 Zürich, Switzerland
| | - W F Graier
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - R Malli
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - F Madeo
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
| | - D Kratky
- Institute of Molecular Biology and Biochemistry, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
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24
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Shin KO, Park MY, Seo CH, Lee YI, Kim HS, Yoo HS, Hong JT, Jung JK, Lee YM. Terpene alcohols inhibit de novo sphingolipid biosynthesis. Planta Med 2012; 78:434-439. [PMID: 22274813 DOI: 10.1055/s-0031-1298155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The terpene alcohols geranyllinalool, phytol (diterpene alcohol), and farnesol (sesquiterpene alcohol) were newly found to inhibit sphingolipid de novo biosynthesis in LLC-PK₁ cells (pig kidney epithelial cells). A simple chromatographic bioassay was established for the screening of inhibitory compounds able to reduce the amount of sphinganine, an intermediate metabolite of sphingolipid biosynthesis. The screening strategy was based on the degree of suppression of fumonisin B₁ (FB₁-induced sphinganine accumulation following co-treatment with selected terpene alcohols. L-cycloserine and ISP-1, specific serine palmitoyltransferase (SPT) inhibitors, were used as positive controls. Our results show that measuring reduced sphinganine levels after treatment with 2 µM FB₁ in combination with the putative inhibitory compounds provides a useful screening bioassay for evaluating compounds causing sphingolipid depletion. Intracellular sphinganine concentrations were analyzed using the fluorescent peak areas of the O-phthalaldehyde (OPA) derivatives of sphinganine eluted with 87 % acetonitrile on a reversed-phase column. Geranyllinalool, phytol, and farnesol were identified as novel SPT inhibitors that reduce FB₁-induced sphinganine accumulation and thus inhibit the first step of sphingolipid de novo synthesis.
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Affiliation(s)
- Kyong-Oh Shin
- College of Pharmacy and MRC, Chungbuk National University, Chongju, Korea
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25
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Figueiredo JM, Rodrigues DC, Silva RCMC, Koeller CM, Jiang JC, Jazwinski SM, Previato JO, Mendonça-Previato L, Urményi TP, Heise N. Molecular and functional characterization of the ceramide synthase from Trypanosoma cruzi. Mol Biochem Parasitol 2011; 182:62-74. [PMID: 22226824 DOI: 10.1016/j.molbiopara.2011.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 12/14/2011] [Accepted: 12/20/2011] [Indexed: 01/21/2023]
Abstract
In this study, we characterized ceramide synthase (CerS) of the protozoan parasite Trypanosoma cruzi at the molecular and functional levels. TcCerS activity was detected initially in a cell-free system using the microsomal fraction of epimastigote forms of T. cruzi, [(3)H]dihydrosphingosine or [(3)H]sphingosine, and fatty acids or acyl-CoA derivatives as acceptor or donor substrates, respectively. TcCerS utilizes both sphingoid long-chain bases, and its activity is exclusively dependent on acyl-CoAs, with palmitoyl-CoA being preferred. In addition, Fumonisin B(1), a broad and well-known acyl-CoA-dependent CerS inhibitor, blocked the parasite's CerS activity. However, unlike observations in fungi, the CerS inhibitors Australifungin and Fumonisin B(1) did not affect the proliferation of epimastigotes in culture, even after exposure to high concentrations or after extended periods of treatment. A search of the parasite genome with the conserved Lag1 motif from Lag1p, the yeast acyl-CoA-dependent CerS, identified a T. cruzi candidate gene (TcCERS1) that putatively encodes the parasite's CerS activity. The TcCERS1 gene was able to functionally complement the lethality of a lag1Δ lac1Δ double deletion yeast mutant in which the acyl-CoA-dependent CerS is not detectable. The complemented strain was capable of synthesizing normal inositol-containing sphingolipids and is 10 times more sensitive to Fumonisin B(1) than the parental strain.
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Affiliation(s)
- Juliana M Figueiredo
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde Bloco G-019, Av. Carlos Chagas Filho 373, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ 21941-902, Brazil
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26
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Saucedo-García M, González-Solís A, Rodríguez-Mejía P, de Jesús Olivera-Flores T, Vázquez-Santana S, Cahoon EB, Gavilanes-Ruiz M. Reactive oxygen species as transducers of sphinganine-mediated cell death pathway. Plant Signal Behav 2011; 6:1616-9. [PMID: 21921699 PMCID: PMC3256400 DOI: 10.4161/psb.6.10.16981] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Long chain bases or sphingoid bases are building blocks of complex sphingolipids that display a signaling role in programmed cell death in plants. So far, the type of programmed cell death in which these signaling lipids have been demonstrated to participate is the cell death that occurs in plant immunity, known as the hypersensitive response. The few links that have been described in this pathway are: MPK6 activation, increased calcium concentrations, and reactive oxygen species (ROS) generation. The latter constitute one of the more elusive loops because of the chemical nature of ROS the multiple possible cell sites where they can be formed and the ways in which they influence cell structure and function.
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Affiliation(s)
- Mariana Saucedo-García
- Departamento de Bioquímica; Fac. de Química; Universidad Nacional Autónoma de México. Cd. Universitaria, México, D.F. 04510 México
| | - Ariadna González-Solís
- Departamento de Bioquímica; Fac. de Química; Universidad Nacional Autónoma de México. Cd. Universitaria, México, D.F. 04510 México
| | - Priscila Rodríguez-Mejía
- Departamento de Bioquímica; Fac. de Química; Universidad Nacional Autónoma de México. Cd. Universitaria, México, D.F. 04510 México
| | - Teresa de Jesús Olivera-Flores
- Departamento de Bioquímica; Fac. de Química; Universidad Nacional Autónoma de México. Cd. Universitaria, México, D.F. 04510 México
| | - Sonia Vázquez-Santana
- Departamento de Bioquímica; Fac. de Química; Universidad Nacional Autónoma de México. Cd. Universitaria, México, D.F. 04510 México
| | - Edgar B Cahoon
- Center for Plant Science Innovation & Department of Biochemistry; University of Nebraska-Lincoln; Lincoln, NE USA
| | - Marina Gavilanes-Ruiz
- Departamento de Bioquímica; Fac. de Química; Universidad Nacional Autónoma de México. Cd. Universitaria, México, D.F. 04510 México
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27
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Saucedo-García M, Guevara-García A, González-Solís A, Cruz-García F, Vázquez-Santana S, Markham JE, Lozano-Rosas MG, Dietrich CR, Ramos-Vega M, Cahoon EB, Gavilanes-Ruíz M. MPK6, sphinganine and the LCB2a gene from serine palmitoyltransferase are required in the signaling pathway that mediates cell death induced by long chain bases in Arabidopsis. New Phytol 2011; 191:943-957. [PMID: 21534970 DOI: 10.1111/j.1469-8137.2011.03727.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Long chain bases (LCBs) are sphingolipid intermediates acting as second messengers in programmed cell death (PCD) in plants. Most of the molecular and cellular features of this signaling function remain unknown. We induced PCD conditions in Arabidopsis thaliana seedlings and analyzed LCB accumulation kinetics, cell ultrastructure and phenotypes in serine palmitoyltransferase (spt), mitogen-activated protein kinase (mpk), mitogen-activated protein phosphatase (mkp1) and lcb-hydroxylase (sbh) mutants. The lcb2a-1 mutant was unable to mount an effective PCD in response to fumonisin B1 (FB1), revealing that the LCB2a gene is essential for the induction of PCD. The accumulation kinetics of LCBs in wild-type (WT) and lcb2a-1 plants and reconstitution experiments with sphinganine indicated that this LCB was primarily responsible for PCD elicitation. The resistance of the null mpk6 mutant to manifest PCD on FB1 and sphinganine addition and the failure to show resistance on pathogen infection and MPK6 activation by FB1 and LCBs indicated that MPK6 mediates PCD downstream of LCBs. This work describes MPK6 as a novel transducer in the pathway leading to LCB-induced PCD in Arabidopsis, and reveals that sphinganine and the LCB2a gene are required in a PCD process that operates as one of the more effective strategies used as defense against pathogens in plants.
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Affiliation(s)
- Mariana Saucedo-García
- Dpto. de Bioquímica, Fac. de Química, Universidad Nacional Autónoma de México, México D.F., 04510 México
| | - Arturo Guevara-García
- Dpto. de Biología Molecular de Plantas, Inst. de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca 62271, Morelos, México
| | - Ariadna González-Solís
- Dpto. de Bioquímica, Fac. de Química, Universidad Nacional Autónoma de México, México D.F., 04510 México
| | - Felipe Cruz-García
- Dpto. de Bioquímica, Fac. de Química, Universidad Nacional Autónoma de México, México D.F., 04510 México
| | - Sonia Vázquez-Santana
- Dpto. de Biología Comparada, Fac. de Ciencias, Universidad Nacional Autónoma de México, México D.F., 04510 México
| | | | - M Guadalupe Lozano-Rosas
- Dpto. de Bioquímica, Fac. de Química, Universidad Nacional Autónoma de México, México D.F., 04510 México
| | | | - Maricela Ramos-Vega
- Dpto. de Biología Molecular de Plantas, Inst. de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca 62271, Morelos, México
| | - Edgar B Cahoon
- Center for Plant Science Innovation & Department of Biochemistry, University of Nebraska-Lincoln, E318 Beadle Center, 1901 Vine St., Lincoln, NE 68588, USA
| | - Marina Gavilanes-Ruíz
- Dpto. de Bioquímica, Fac. de Química, Universidad Nacional Autónoma de México, México D.F., 04510 México
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Abstract
Cysteine proteases such as caspases play important roles in programmed cell death (PCD) of metazoans. Plant metacaspases (MCPs), a family of cysteine proteases structurally related to caspases, have been hypothesized to be ancestors of metazoan caspases, despite their different substrate specificity. Arabidopsis thaliana contains six type II MCP genes (AtMCP2a-f). Whether and how these individual members are involved in controlling PCD in plants remains largely unknown. Here we investigated the function and regulation of AtMCP2d, the predominant and constitutively expressed member of type II MCPs, in stress-inducible PCD. Two AtMCP2d mutants (mcp2d-1 and mcp2d-3) exhibited reduced sensitivity to PCD-inducing mycotoxin fumonisin B1 as well as oxidative stress inducers, whereas AtMCP2d over-expressors were more sensitive to these agents, and exhibited accelerated cell-death progression. We found that AtMCP2d exclusively localizes to the cytosol, and its accumulation and self-processing patterns were age-dependent in leaves. Importantly, active proteolytic processing of AtMCP2d proteins dependent on its catalytic activity was observed in mature leaves during mycotoxin-induced cell death. We also found that mcp2d-1 leaves exhibited reduced cell death in response to Pseudomonas syringae carrying avirulent gene avrRpt2, and that self-processing of AtMCP2d was also detected in wild-type leaves in response to this pathogen. Furthermore, increases in processed AtMCP2d proteins were found to correlate with conditional cell-death induction in two lesion-mimic mutants (cpr22 and ssi4) that exhibit spontaneous cell-death phenotypes. Taken together, our data strongly suggest that AtMCP2d plays a positive regulatory role in biotic and abiotic stress-induced PCD.
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Affiliation(s)
- Naohide Watanabe
- Department of Plant Biology and Pathology, School of Environmental and Biological Sciences, Rutgers University, New Brunswick, NJ 08901-8550, USA
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Löhrke B, Weitzel JM, Krüger B, Xu J, Vernunft A, Viergutz T. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) activity decreases estrogenesis in ovarian granulosa cells. Cytometry A 2011; 79:669-71. [PMID: 21595015 DOI: 10.1002/cyto.a.21082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 04/13/2011] [Accepted: 04/27/2011] [Indexed: 11/06/2022]
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He S, Tan G, Liu Q, Huang K, Ren J, Zhang X, Yu X, Huang P, An C. The LSD1-interacting protein GILP is a LITAF domain protein that negatively regulates hypersensitive cell death in Arabidopsis. PLoS One 2011; 6:e18750. [PMID: 21526181 PMCID: PMC3079718 DOI: 10.1371/journal.pone.0018750] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 03/17/2011] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Hypersensitive cell death, a form of avirulent pathogen-induced programmed cell death (PCD), is one of the most efficient plant innate immunity. However, its regulatory mechanism is poorly understood. AtLSD1 is an important negative regulator of PCD and only two proteins, AtbZIP10 and AtMC1, have been reported to interact with AtLSD1. METHODOLOGY/PRINCIPAL FINDINGS To identify a novel regulator of hypersensitive cell death, we investigate the possible role of plant LITAF domain protein GILP in hypersensitive cell death. Subcellular localization analysis showed that AtGILP is localized in the plasma membrane and its plasma membrane localization is dependent on its LITAF domain. Yeast two-hybrid and pull-down assays demonstrated that AtGILP interacts with AtLSD1. Pull-down assays showed that both the N-terminal and the C-terminal domains of AtGILP are sufficient for interactions with AtLSD1 and that the N-terminal domain of AtLSD1 is involved in the interaction with AtGILP. Real-time PCR analysis showed that AtGILP expression is up-regulated by the avirulent pathogen Pseudomonas syringae pv. tomato DC3000 avrRpt2 (Pst avrRpt2) and fumonisin B1 (FB1) that trigger PCD. Compared with wild-type plants, transgenic plants overexpressing AtGILP exhibited significantly less cell death when inoculated with Pst avrRpt2, indicating that AtGILP negatively regulates hypersensitive cell death. CONCLUSIONS/SIGNIFICANCE These results suggest that the LITAF domain protein AtGILP localizes in the plasma membrane, interacts with AtLSD1, and is involved in negatively regulating PCD. We propose that AtGILP functions as a membrane anchor, bringing other regulators of PCD, such as AtLSD1, to the plasma membrane. Human LITAF domain protein may be involved in the regulation of PCD, suggesting the evolutionarily conserved function of LITAF domain proteins in the regulation of PCD.
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Affiliation(s)
- Shanping He
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Guihong Tan
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Qian Liu
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Kuowei Huang
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Jiao Ren
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Xu Zhang
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Xiangchun Yu
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Ping Huang
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
| | - Chengcai An
- The State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
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Aubert A, Marion J, Boulogne C, Bourge M, Abreu S, Bellec Y, Faure JD, Satiat-Jeunemaitre B. Sphingolipids involvement in plant endomembrane differentiation: the BY2 case. Plant J 2011; 65:958-71. [PMID: 21205030 DOI: 10.1111/j.1365-313x.2011.04481.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Sphingolipids play an essential role in the functioning of the secretory pathway in eukaryotic organisms. Their importance in the functional organization of plant cells has not been studied in any detail before. The sphingolipid synthesis inhibitor fumonisin B1 (FB1), a mycotoxin acting as a specific inhibitor of ceramide synthase, was tested for its effects on cell growth, cell polarity, cell shape, cell cycle and on the ultrastructure of BY2 cells. We used cell lines expressing different GFP-tagged markers for plant cell compartments, as well as a Golgi marker fused to the photoconvertible protein Kaede. Light and electron microscopy, combined with flow cytometry, were applied to analyse the morphodynamics and architecture of compartments of the secretory pathway. The results indicate that FB1 treatment had severe effects on cell growth and cell shape, and induced a delay in cell division processes. The cell changes were accompanied by the formation of the endoplasmic reticulum (ER)-derived tubular aggregates (FB1-induced compartments), together with an inhibition of cargo transport from the ER to the Golgi apparatus. A change in polar localization of the auxin transporter PIN1 was also observed, but endocytic processes were little affected. Electron microscopy studies confirmed that molecular FB1 targets were distinct from brefeldin A (BFA) targets. We propose that the reported effects of inhibition of ceramide biosynthesis reflect the importance of sphingolipids during cell growth and establishment of cell polarity in higher plant cells, notably through their contribution to the functional organization of the ER or its differentiation into distinct compartments.
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Affiliation(s)
- Anne Aubert
- Laboratoire Dynamique de la Compartimentation Cellulaire, CNRS UPR2355/IFR87, Institut des Sciences du Végétal, Centre de Recherche de Gif (FRC3115), 91198, Gif-sur-Yvette Cedex, France
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Chivasa S, Tomé DFA, Hamilton JM, Slabas AR. Proteomic analysis of extracellular ATP-regulated proteins identifies ATP synthase beta-subunit as a novel plant cell death regulator. Mol Cell Proteomics 2011; 10:M110.003905. [PMID: 21156838 PMCID: PMC3047153 DOI: 10.1074/mcp.m110.003905] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/24/2010] [Indexed: 12/27/2022] Open
Abstract
Extracellular ATP is an important signal molecule required to cue plant growth and developmental programs, interactions with other organisms, and responses to environmental stimuli. The molecular targets mediating the physiological effects of extracellular ATP in plants have not yet been identified. We developed a well characterized experimental system that depletes Arabidopsis cell suspension culture extracellular ATP via treatment with the cell death-inducing mycotoxin fumonisin B1. This provided a platform for protein profile comparison between extracellular ATP-depleted cells and fumonisin B1-treated cells replenished with exogenous ATP, thus enabling the identification of proteins regulated by extracellular ATP signaling. Using two-dimensional difference in-gel electrophoresis and matrix-assisted laser desorption-time of flight MS analysis of microsomal membrane and total soluble protein fractions, we identified 26 distinct proteins whose gene expression is controlled by the level of extracellular ATP. An additional 48 proteins that responded to fumonisin B1 were unaffected by extracellular ATP levels, confirming that this mycotoxin has physiological effects on Arabidopsis that are independent of its ability to trigger extracellular ATP depletion. Molecular chaperones, cellular redox control enzymes, glycolytic enzymes, and components of the cellular protein degradation machinery were among the extracellular ATP-responsive proteins. A major category of proteins highly regulated by extracellular ATP were components of ATP metabolism enzymes. We selected one of these, the mitochondrial ATP synthase β-subunit, for further analysis using reverse genetics. Plants in which the gene for this protein was knocked out by insertion of a transfer-DNA sequence became resistant to fumonisin B1-induced cell death. Therefore, in addition to its function in mitochondrial oxidative phosphorylation, our study defines a new role for ATP synthase β-subunit as a pro-cell death protein. More significantly, this protein is a novel target for extracellular ATP in its function as a key negative regulator of plant cell death.
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Affiliation(s)
- Stephen Chivasa
- From the ‡School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom
| | - Daniel F. A. Tomé
- From the ‡School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom
| | - John M. Hamilton
- From the ‡School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom
| | - Antoni R. Slabas
- From the ‡School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom
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Basnayake BMVS, Li D, Zhang H, Li G, Virk N, Song F. Arabidopsis DAL1 and DAL2, two RING finger proteins homologous to Drosophila DIAP1, are involved in regulation of programmed cell death. Plant Cell Rep 2011; 30:37-48. [PMID: 20972793 DOI: 10.1007/s00299-010-0941-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 10/03/2010] [Accepted: 10/12/2010] [Indexed: 05/12/2023]
Abstract
Programmed cell death (PCD) is a precise, genetically controlled cellular process with important roles in plant growth, development, and response to biotic and abiotic stress. However, the genetic mechanisms that control PCD in plants are unclear. Two Arabidopsis genes, DAL1 and DAL2 (for Drosophila DIAP1 like 1 and 2), encoding RING finger proteins with homology to DIAP1 were identified, and a series of experiments were performed to elucidate their roles in the regulation of PCD and disease resistance. Expression of DAL1 and DAL2 genes was induced in Arabidopsis plants after inoculation with virulent and avirulent strains of Pseudomonas syrinage pv. tomato (Pst) DC3000 or after infiltration with fumonisin B1 (FB1). Plants with mutations in the DAL1 and DAL2 genes displayed more severe disease after inoculation with an avirulent strain of Pst DC3000, but they showed similar disease severity as the wild-type plant after inoculation with a virulent strain of Pst DC3000. Significant accumulations of reactive oxygen species (ROS) and increased cell death were observed in the dal1 and dal2 mutant plants after inoculation with the avirulent strain of Pst DC3000. The dal mutant plants underwent extensive PCD upon infiltration of FB1 and displayed higher levels of ROS accumulation, callose deposition, and autofluorescence than the wild-type plants. Our data suggest that DAL1 and DAL2 may act as negative regulators of PCD in Arabidopsis.
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Affiliation(s)
- B M Vindhya S Basnayake
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University, Huajiachi Campus, Hangzhou 310029, Zhejiang, People's Republic of China
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Goldfinger M, Shmuel M, Benhamron S, Tirosh B. Protein synthesis in plasma cells is regulated by crosstalk between endoplasmic reticulum stress and mTOR signaling. Eur J Immunol 2010; 41:491-502. [PMID: 21268018 DOI: 10.1002/eji.201040677] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 10/04/2010] [Accepted: 11/19/2010] [Indexed: 01/22/2023]
Abstract
Plasma cells (PCs) secrete copious levels of immunoglobulins. To achieve this, their endoplasmic reticulum (ER) undergoes expansion in a process that requires continuous ER stress and activation of the unfolded protein response. It is important that protein synthesis, the driver of ER stress, is regulated in a manner that does not induce apoptosis. We followed protein synthesis in murine splenic B cells activated in vitro with LPS. Total protein synthesis levels increased and then steeply decreased when the cells acquired a secretory phenotype. We explored the involvement of two mechanisms in controlling protein synthesis levels, namely ER stress-mediated phosphorylation of eukaryote initiation factor 2α (eIF2α) and the mammalian target of rapamycin (mTOR) pathway, which attenuate or activate mRNA translation, respectively. We show that induction of ER stress in activated B cells counter-intuitively led to dephosphorylation of eIF2α. Despite the reduction in phosphorylated eIF2α, expression of activating transcription factor 4, an effector of hyper eIF2α phosphorylation, was induced. In addition, ER stress attenuated the mTOR pathway, which ultimately reduced protein synthesis. Finally, B cells engineered to overactivate the mTOR pathway exhibited higher apoptosis in the course of LPS stimulation. We conclude that protein synthesis in PCs is controlled by an ER stress-mediated mTOR regulation, which is needed for optimal cell viability.
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Affiliation(s)
- Meidan Goldfinger
- Institute for Drug Research, The School of Pharmacy, The Hebrew University, Jerusalem, Israel
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Kłosowski G, Mikulski D, Grajewski J, Błajet-Kosicka A. The influence of raw material contamination with mycotoxins on alcoholic fermentation indicators. Bioresour Technol 2010; 101:3147-52. [PMID: 20074946 DOI: 10.1016/j.biortech.2009.12.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 12/11/2009] [Accepted: 12/15/2009] [Indexed: 05/16/2023]
Abstract
The aim of the research was to describe the influence of selected mycotoxins on major factors (alcohol concentration, productivity, yield and energy) that are characteristic of the fermentation process of maize mashes. Indicators of the alcoholic fermentation of mashes made from raw material with low contaminations levels were compared with mashes obtained from raw material that was selectively contaminated with mycotoxins on the following concentrations: aflatoxin B(1)-11.65 ppb, B(2)-12.60 ppb, G(1)-12.34 ppb, G(2)-12.04 ppb; ochratoxin A-177.5 ppb; zearalenone-352 ppb; deoxynivalenol-2274 ppb; fumonisin B(1)-1875 ppb, B(2)-609 ppb, B(3)-195 ppb. It was found that, apart from fumonisin, all mycotoxins substantially affected the course of subsequent fermentation phases, in particular the first and the main fermentation phases. The highest drop in alcohol concentration at the main stage of the process amounted to 1% v/v and it was achieved by contamination with zearalenone. The statistically significant drop in the final fermentation yield was observed; this was caused by raw material contaminated with all studied mycotoxins, except for fumonisin. The decrease in ethanol yield in reference to the control variant ranged from 1.42 to 3.20 dm(3) of absolute alcohol out of 100 kg of starch, depending on a toxin.
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Affiliation(s)
- Grzegorz Kłosowski
- Kazimierz Wielki University, Department of Biotechnology, Laboratory of Fermentation Technology, 85-064 Bydgoszcz, ul. Chodkiewicza 30, Poland.
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Hayashi T, Fujimoto M. Detergent-resistant microdomains determine the localization of sigma-1 receptors to the endoplasmic reticulum-mitochondria junction. Mol Pharmacol 2010; 77:517-28. [PMID: 20053954 PMCID: PMC2845942 DOI: 10.1124/mol.109.062539] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Accepted: 01/06/2010] [Indexed: 01/04/2023] Open
Abstract
Sigma-1 receptors (Sig-1Rs) that bind diverse synthetic and endogenous compounds have been implicated in the pathophysiology of several human diseases such as drug addiction, depression, neurodegenerative disorders, pain-related disorders, and cancer. Sig-1Rs were identified recently as novel ligand-operated molecular chaperones. Although Sig-1Rs are predominantly expressed at endoplasmic reticulum (ER) subdomains apposing mitochondria [i.e., the mitochondria-associated ER membrane (MAM)], they dynamically change the cellular distribution, thus regulating both MAM-specific and plasma membrane proteins. However, what determines the location of Sig-1R at the MAM and how the receptor translocation is initiated is unknown. Here we report that the detergent-resistant membranes (DRMs) play an important role in anchoring Sig-1Rs to the MAM. The MAM, which is highly capable of accumulating ceramides, is enriched with both cholesterol and simple sphingolipids, thus forming Triton X-114-resistant DRMs. Sig-1Rs associate with MAM-derived DRMs but not with those from microsomes. A lipid overlay assay found that solubilized Sig-1Rs preferentially associate with simple sphingolipids such as ceramides. Disrupting DRMs by lowering cholesterol or inhibiting de novo synthesis of ceramides at the ER largely decreases Sig-1R at DRMs and causes translocation of Sig-1R from the MAM to ER cisternae. These findings suggest that the MAM, bearing cholesterol and ceramide-enriched microdomains at the ER, may use the microdomains to anchor Sig-1Rs to the location; thus, it serves to stage Sig-1R at ER-mitochondria junctions.
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Affiliation(s)
- Teruo Hayashi
- Cellular Pathobiology Section, Cellular Neurobiology Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224, USA.
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Abstract
Ceramide synthases (CerS) are integral membrane proteins of the endoplasmic reticulum. Six mammalian CerS have been described, with each utilizing fatty acyl CoAs of relatively defined chain lengths for N-acylation of the sphingoid long chain base. In this chapter, we review the main functional features of the CerS proteins, discuss their fatty acid specificity, kinetics, tissue distribution and mode of inhibition, as well as possible posttranslational modifications. We then address the reason that mammals contain six distinct CerS, whereas most other enzymes in the sphingolipid biosynthetic pathway only occur in one or two isoforms. Finally, we discuss the putative roles of CerS and the ceramide derived from the CerS, in signaling pathways and in development of disease.
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Affiliation(s)
- Johnny Stiban
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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Raa H, Grimmer S, Schwudke D, Bergan J, Wälchli S, Skotland T, Shevchenko A, Sandvig K. Glycosphingolipid requirements for endosome-to-Golgi transport of Shiga toxin. Traffic 2009; 10:868-82. [PMID: 19453975 DOI: 10.1111/j.1600-0854.2009.00919.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Shiga toxin binds to globotriaosylceramide (Gb3) receptors on the target cell surface. To enter the cytosol, Shiga toxin is dependent on endocytic uptake, retrograde transport to the Golgi apparatus and further to the endoplasmic reticulum before translocation of the enzymatically active moiety to the cytosol. Here, we have investigated the importance of newly synthesized glycosphingolipids for the uptake and intracellular transport of Shiga toxin in HEp-2 cells. Inhibition of glycosphingolipid synthesis by treatment with either PDMP or Fumonisin B(1) for 24-48 h strongly reduced the transport of Gb3-bound Shiga toxin from endosomes to the Golgi apparatus. This was associated with a change in localization of sorting nexins 1 and 2, and accompanied by a protection against the toxin. In contrast, there was no effect on transport or toxicity of the plant toxin ricin. High-resolution mass spectrometry revealed a 2-fold reduction in Gb3 at conditions giving a 10-fold inhibition of Shiga toxin transport to the Golgi. Furthermore, mass spectrometry showed that the treatment with PDMP (DL-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol) and Fumonisin B(1) among other changes of the lipidome, affected the relative content of the different glycosphingolipid species. The largest depletion was observed for the hexosylceramide species with the N-amidated fatty acid 16:0, whereas hexosylceramide species with 24:1 were less affected. Quantitative lipid profiling with mass spectrometry demonstrated that PDMP did not influence the content of sphingomyelins, phospholipids and plasmalogens. In contrast, Fumonisin B(1) affected the amount and composition of sphingomyelin and glycolipids and altered the profiles of phospholipids and plasmalogens.
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Affiliation(s)
- Hilde Raa
- Centre for Cancer Biomedicine, Faculty Division Norwegian Radium Hospital, University of Oslo, 0316 Oslo, Norway
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Ivanchenko OB, Martynova EA. [Genetic mechanisms of E. coli cell stability to the antibiotics]. Vopr Pitan 2009; 78:49-53. [PMID: 19348283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Mycotoxin Fumonisin B1 posseesses the weak DNA-damage activity for the E. coli strain defective in UvrA gene participating in DNA reparation. Fumonisin B1 in the concentration 10(-5) M increases a resistance of wild type E. coli cells to antibiotic doxycycline. Obtained results indicate the influence of fumonisin B1 on the genome of the cultured E. coli cells.
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Gelineau-van Waes J, Voss KA, Stevens VL, Speer MC, Riley RT. Maternal fumonisin exposure as a risk factor for neural tube defects. Adv Food Nutr Res 2009; 56:145-181. [PMID: 19389609 DOI: 10.1016/s1043-4526(08)00605-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Fumonisins are mycotoxins produced by the fungus F. verticillioides, a common contaminant of maize (corn) worldwide. Maternal consumption of fumonisin B(1)-contaminated maize during early pregnancy has recently been associated with increased risk for neural tube defects (NTDs) in human populations that rely heavily on maize as a dietary staple. Experimental administration of purified fumonisin to mice early in gestation also results in an increased incidence of NTDs in exposed offspring. Fumonisin inhibits the enzyme ceramide synthase in de novo sphingolipid biosynthesis, resulting in an elevation of free sphingoid bases and depletion of downstream glycosphingolipids. Increased sphingoid base metabolites (i.e., sphinganine-1-phosphate) may perturb signaling cascades involved in embryonic morphogenesis by functioning as ligands for sphingosine-1-P (S1P) receptors, a family of G-protein-coupled receptors that regulate key biological processes such as cell survival/proliferation, differentiation and migration. Fumonisin-induced depletion of glycosphingolipids impairs expression and function of the GPI-anchored folate receptor (Folr1), which may also contribute to adverse pregnancy outcomes. NTDs appear to be multifactorial in origin, involving complex gene-nutrient-environment interactions. Vitamin supplements containing folic acid have been shown to reduce the occurrence of NTDs, and may help protect the developing fetus from environmental teratogens. Fumonisins appear to be an environmental risk factor for birth defects, although other aspects of maternal nutrition and genetics play interactive roles in determining pregnancy outcome. Minimizing exposures to mycotoxins through enhanced agricultural practices, identifying biomarkers of exposure, characterizing mechanisms of toxicity, and improving maternal nutrition are all important strategies for reducing the NTD burden in susceptible human populations.
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Affiliation(s)
- J Gelineau-van Waes
- Department of Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Direito GM, Almeida AP, Aquino S, dos Reis TA, Pozzi CR, Corrêa B. Evaluation of sphingolipids in Wistar rats treated to prolonged and single oral doses of fumonisin b₁. Int J Mol Sci 2008; 10:50-61. [PMID: 19333435 PMCID: PMC2662460 DOI: 10.3390/ijms10010050] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 12/12/2008] [Accepted: 12/17/2008] [Indexed: 11/16/2022] Open
Abstract
The objective of the present study was to evaluate sphingolipid levels (sphingosine-So and sphinganine-Sa) and to compare the Sa/So ratio in liver, serum and urine of Wistar rats after prolonged administration (21 days) of fumonisin B(1) (FB(1)). In parallel, the kinetics of sphingolipid elimination in urine was studied in animals receiving a single dose of FB(1). Prolonged exposure to FB(1) caused an increase in Sa levels in urine, serum and liver. The most marked effect on sphingolipid biosynthesis was observed in animals treated with the highest dose of FB(1). Animals receiving a single dose of FB(1) presented variations in Sa and So levels and in the Sa/So ratio.
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Affiliation(s)
- Glória M. Direito
- Departamento de Microbiologia e Imunologia, Instituto de Veterinária da Universidade Federal Rural do Rio de Janeiro, CEP 23890.000, Rio de Janeiro, RJ, Brasil. E-Mail:
| | - Adriana P. Almeida
- Departamento de Bromatologia e Química do Instituto Adolfo Lutz, CEP. 01246-902, São Paulo, Brasil. E-Mail:
| | - Simone Aquino
- Instituto de Pesquisa Energéticas e Nucleares (IPEN / CNEN - SP), CEP 05508-000, São Paulo, SP, Brasil. E-Mail:
| | - Tatiana Alves dos Reis
- Departamento de Microbiologia do Instituto de Ciências Biomédicas da Universidade de São Paulo, CEP: 05508-900, São Paulo, SP, Brasil. E-Mail:
| | | | - Benedito Corrêa
- Departamento de Microbiologia do Instituto de Ciências Biomédicas da Universidade de São Paulo, CEP: 05508-900, São Paulo, SP, Brasil. E-Mail:
- * Author to whom correspondence should be addressed; E-Mail:
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Abstract
Cationic lipid/DNA-complexes have been widely used as gene transfer vectors because they are less toxic and immunogenic than viral vectors. The aim of the present study was to improve and characterize lipofection of an insulin-producing cell line. We compared the transfection efficiency of seven commercially available lipid formulations (Lipotaxi, SuperFect, Fugene, TransFast, Dosper, GenePORTER and LipofectAMINE) by flow cytometry analysis of GFP-expression. In addition, we have determined the influences of centrifugation, serum and a nuclear localization signal peptide on the lipofection efficiency. We observed that two lipid formulations, GenePORTER and LipofectAMINE, were able to promote efficient gene transfer in RINm5F cells. However, GenePORTER exhibited the important advantage of being able to transfect cells in the presence of serum and with less cytotoxicity than LipofectAMINE. LipofectAMINE-induced RINm5F cell death could partially be counteracted by TPA, forskolin or fumonisin beta(1). Finally, both centrifugation and a nuclear localization signal peptide increased transfection efficiency.
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Affiliation(s)
- Andreea Barbu
- Department of Medical Cell Biology, Uppsala University.,Uppsala.,Sweden.
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43
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Lin SS, Martin R, Mongrand S, Vandenabeele S, Chen KC, Jang IC, Chua NH. RING1 E3 ligase localizes to plasma membrane lipid rafts to trigger FB1-induced programmed cell death in Arabidopsis. Plant J 2008; 56:550-61. [PMID: 18643987 DOI: 10.1111/j.1365-313x.2008.03625.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ubiquitination plays important roles in plant development, including programmed cell death. Here, we characterize a novel membrane-bound RING motif protein, encoded by RING1, that is expressed at a low level in all Arabidopsis tissues but can be upregulated by fumonisin B1 (FB1) treatment and pathogen infection. RING1 displays E3 ubiquitin ligase activity in vitro, which is dependent on the integrity of the RING motif. GFP fusion protein localization and cell fractionation experiments show that this E3 ligase is associated with the lipid rafts of plasma membranes. Knock-down of RING1 transcripts using artificial microRNA (amiR-R1(159)) leads to FB1 hyposensitivity, but overexpression of RING1 confers hypersensitivity. Additionally, expression of the pathogenesis-related 1 (PR-1) gene is lower and delayed in amiR-R1(159) plants compared with wild-type and RING1-overexpressing plants. The FB1 hyposensitivity of amiR-R1(159) plants can be rescued by expression of cleavage-resistant RING1mut transcripts. Our results suggest that RING1 acts as a signal from the plasma membrane lipid rafts to trigger the FB1-induced plant programmed cell death pathway.
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Affiliation(s)
- Shih-Shun Lin
- Laboratory of Plant Molecular Biology, Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
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Kim JE, Ahn MW, Baek SH, Lee IK, Kim YW, Kim JY, Dan JM, Park SY. AMPK activator, AICAR, inhibits palmitate-induced apoptosis in osteoblast. Bone 2008; 43:394-404. [PMID: 18502715 DOI: 10.1016/j.bone.2008.03.021] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 03/06/2008] [Accepted: 03/16/2008] [Indexed: 12/28/2022]
Abstract
Osteoblast apoptosis reduces bone mineral density. Apoptosis can be induced in a variety of cells by palmitate, which is one of the most common saturated fatty acids in dietary fat. The AMPK activator, AICAR, has been shown to inhibit palmitate-induced apoptosis. However, the role of palmitate in osteoblast apoptosis is currently unknown. This study examined whether palmitate could induce apoptosis in osteoblasts, and if so, whether AICAR could alleviate palmitate-induced apoptosis. Palmitate reduced cell survival and induced apoptosis in a dose- and time-dependent manner in human fetal osteoblasts (hFOB) 1.19. While the long-chain acyl-CoA synthetase inhibitor, triacsin C, inhibited palmitate-induced apoptosis, anti-oxidants and ceramide synthesis inhibitors did not attenuate the apoptosis. AICAR prevented palmitate-induced apoptosis and the inhibition of AICAR-mediated increase in fatty acid oxidation by etomoxir did not affect the prevention of apoptosis by AICAR. Constitutively-active AMPK also inhibited palmitate-induced apoptosis. Treatment with an AMPK inhibitor (compound C) and a dominant-negative AMPK adenovirus suppressed the inhibitory effect of AICAR on apoptosis. Palmitate impaired the activation of ERK by fetal bovine serum, which was blocked by AICAR. Moreover, AICAR increased ERK activation, and ERK inhibitors, PD98059 and U0126, as well as a dominant-negative MEK1, abolished the inhibitory effect of AICAR on palmitate-induced apoptosis. AICAR also inhibited palmitate-induced apoptosis in osteoblastic differentiated cells from human bone marrow, which was accompanied by recovered ERK activity. These results suggest that palmitate induces apoptosis in osteoblasts through the impaired activation of ERK, and the activation of AMPK inhibits palmitate-induced apoptosis by activating ERK.
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Affiliation(s)
- Ji-Eun Kim
- Department of Physiology, College of Medicine, Yeungnam University, Daegu, South Korea; Aging-associated Vascular Disease Research Center, Yeungnam University, Daegu, South Korea
| | - Myun-Whan Ahn
- Department of Orthopedics, College of Medicine, Yeungnam University, Daegu, South Korea
| | - Suk-Hwan Baek
- Aging-associated Vascular Disease Research Center, Yeungnam University, Daegu, South Korea; Department of Biochemistry and Molecular Biology, College of Medicine, Yeungnam University, Daegu, South Korea
| | - In Kyu Lee
- Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, South Korea
| | - Yong-Woon Kim
- Department of Physiology, College of Medicine, Yeungnam University, Daegu, South Korea
| | - Jong-Yeon Kim
- Department of Physiology, College of Medicine, Yeungnam University, Daegu, South Korea
| | - Jin-Myoung Dan
- Department of Orthopedics, College of Medicine, Pochun Cha University, Kumi, South Korea
| | - So-Young Park
- Department of Physiology, College of Medicine, Yeungnam University, Daegu, South Korea; Aging-associated Vascular Disease Research Center, Yeungnam University, Daegu, South Korea.
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Odhav B, Adam JK, Bhoola KD. Modulating effects of fumonisin B1 and ochratoxin A on leukocytes and messenger cytokines of the human immune system. Int Immunopharmacol 2008; 8:799-809. [PMID: 18442783 DOI: 10.1016/j.intimp.2008.01.030] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2007] [Revised: 01/26/2008] [Accepted: 01/28/2008] [Indexed: 11/29/2022]
Affiliation(s)
- Bharti Odhav
- Department of Biotechnology, Durban University of Technology, Durban, South Africa
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Seiferlein M, Humpf HU, Voss KA, Sullards MC, Allegood JC, Wang E, Merrill AH. Hydrolyzed fumonisins HFB1 and HFB2 are acylated in vitro and in vivo by ceramide synthase to form cytotoxic N-acyl-metabolites. Mol Nutr Food Res 2007; 51:1120-30. [PMID: 17729221 DOI: 10.1002/mnfr.200700118] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Fumonisins B1 and B2 (FB1 and FB2) are the most abundant members of the fumonisins--mycotoxins that are produced by Fusarium verticillioides and are natural inhibitors of ceramide synthase. Their hydrolyzed forms, HFB1 and HFB2 (also called AP1 and AP2) are found in some foods, and they are not only inhibitors of ceramide synthase but also undergo acylation by this enzyme. This study characterized the conversion of HFB1 and HFB2 by ceramide synthase to their respective N-acylated metabolites using rat liver microsomes and palmitoyl-CoA or nervonoyl-CoA as cosubstrates, and examined animals that had been dosed with hydrolyzed fumonisins to ascertain if acylation occurs in vivo. Using an HPLC-MS/MS method that allowed the sensitive and selective detection of the acylation products, both HFB1 and HFB2 were found to be metabolized in vitro to nervonoyl- or palmitoyl-HFB1 and -HFB2 (i.e. C24:1-HFB1/2 and C16-HFB1/2, respectively). The apparent vmax was considerably higher for formation of C24:1HFB1 (157 pmol/min/mg protein) than for formation of C16HFB1 (8.7 pmol/min/mg protein). The acylation products also inhibited ceramide synthase and significantly reduced the number of viable cells in an in vitro [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)] assay using a human colonic cell line (HT29). Furthermore, HPLC-MS/MS analysis of tissues from rats given intraperitoneal doses of HFB1 confirmed that formation of N-acyl-HFB1 occurs in vivo to produce metabolites with fatty acids of various chain lengths. The contribution of acylated HFB1 and HFB2 metabolites to fumonisin toxicity in vivo warrants further investigation.
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Le Stunff H, Giussani P, Maceyka M, Lépine S, Milstien S, Spiegel S. Recycling of sphingosine is regulated by the concerted actions of sphingosine-1-phosphate phosphohydrolase 1 and sphingosine kinase 2. J Biol Chem 2007; 282:34372-80. [PMID: 17895250 DOI: 10.1074/jbc.m703329200] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In yeast, the long-chain sphingoid base phosphate phosphohydrolase Lcb3p is required for efficient ceramide synthesis from exogenous sphingoid bases. Similarly, in this study, we found that incorporation of exogenous sphingosine into ceramide in mammalian cells was regulated by the homologue of Lcb3p, sphingosine-1-phosphate phosphohydrolase 1 (SPP-1), an endoplasmic reticulum resident protein. Sphingosine incorporation into endogenous long-chain ceramides was increased by SPP-1 overexpression, whereas recycling of C(6)-ceramide into long-chain ceramides was not altered. The increase in ceramide was inhibited by fumonisin B(1), an inhibitor of ceramide synthase, but not by ISP-1, an inhibitor of serine palmitoyltransferase, the rate-limiting step in the de novo biosynthesis of ceramide. Mass spectrometry analysis revealed that SPP-1 expression increased the incorporation of sphingosine into all ceramide acyl chain species, particularly enhancing C16:0, C18:0, and C20:0 long-chain ceramides. The increased recycling of sphingosine into ceramide was accompanied by increased hexosylceramides and, to a lesser extent, sphingomyelins. Sphingosine kinase 2, but not sphingosine kinase 1, acted in concert with SPP-1 to regulate recycling of sphingosine into ceramide. Collectively, our results suggest that an evolutionarily conserved cycle of phosphorylation-dephosphorylation regulates recycling and salvage of sphingosine to ceramide and more complex sphingolipids.
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Affiliation(s)
- Hervé Le Stunff
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
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48
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Abdel Nour AM, Ringot D, Guéant JL, Chango A. Folate receptor and human reduced folate carrier expression in HepG2 cell line exposed to fumonisin B1 and folate deficiency. Carcinogenesis 2007; 28:2291-7. [PMID: 17615259 DOI: 10.1093/carcin/bgm149] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Fumonisin B1 (FB1) induces apoptosis and decreases the cellular uptake of 5-methyltetrahydrofolate. Two folate transporters (folate receptor, FR, and Reduced Folate Carrier, hRFC1) are involved in the cell uptake of folate. We aimed to study whether FB1 modifies the expression of the FR and the hRFC1 and whether its apoptotic effect is influenced by folate. Incubation of HepG2 cells with FB1 induced apoptosis in concentration and time-dependent manner in complete medium (experimental control medium, ECM), as well as in folate-depleted medium (FDM). FDM increased the toxicity of FB1 as the cells developed apoptosis within 24 h at 1 microM of FB1 instead of 100 microM in ECM. Whereas FR protein expression in cells grown in ECM was significantly inhibited after apoptosis event, protein expression of the hRFC1 was rather increased. The hrfc1 transcription was decreased in the treated cells. Under folate-deficient conditions, dramatic changes were observed on both transcriptional and post-transcriptional expression of the two transporters. FDM alone reduced FR protein expression by 12 +/- 2% and 43 +/- 1% at 48 and 72 h, respectively. The 5-methytetrahydrofolate attenuates apoptosis in a greater extent than the folic acid. However, its effects in preventing decrease of both folate transporters have not been observed. In conclusion, this study shows that the changes in the expression of FR after FB1 addition are probably a consequence of the FB1 toxicity. The response to FB1 by HepG2 cell lines is influenced by folate status and by folate form. 5-methyltetrahydrofolate appears to be more effective in preventing apoptosis than folic acid.
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Affiliation(s)
- Afif M Abdel Nour
- Laboratory of Nutritional Genomics, Institut Polytechnique LaSalle Beauvais-Agrohealth EGEAL, 19 rue Pierre Waguet, F-60026 Beauvais cedex, France
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Lee WK, Torchalski B, Thévenod F. Cadmium-induced ceramide formation triggers calpain-dependent apoptosis in cultured kidney proximal tubule cells. Am J Physiol Cell Physiol 2007; 293:C839-47. [PMID: 17596294 DOI: 10.1152/ajpcell.00197.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A major target of cadmium (Cd2+) toxicity is the kidney proximal tubule (PT) cell. Cd2+-induced apoptosis of PT cells is mediated by sequential activation of calpains at 3–6 h and caspases-9 and -3 after 24-h exposure. Calpains also partly contribute to caspase activation, which emphasizes the importance of calpains for PT apoptosis by Cd2+. Upstream processes underlying Cd2+-induced calpain activation remain unclear. We describe for the first time that 10–50 μM Cd2+ causes a significant increase in ceramide formation by ∼22% (3 h) and ∼72% (24 h), as measured by diacylglycerol kinase assay. Inhibition of ceramide synthase with fumonisin B1 (3 μM) prevents ceramide formation at 3 h and abolishes calpain activation at 6 h, which is associated with significant attenuation of apoptosis at 3–6 h with Hoechst 33342 nuclear staining and/or 3(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2 H-tetrazolium bromide (MTT) death assays. This indicates that Cd2+ enhances de novo ceramide synthesis and that calpains are a downstream target of ceramides in apoptosis execution. Moreover, addition of C6-ceramide to PT cells increases cytosolic Ca2+ and activates calpains. Apoptosis mediated by C6-ceramide at 24 h is significantly reduced by caspase-3 inhibition, which supports cross talk between calpain- and caspase-dependent apoptotic pathways. We conclude that Cd2+-induced apoptosis of PT cells entails endogenous ceramide elevation and subsequent Ca2+-dependent calpain activation, which propagates kidney damage by Cd2+.
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Affiliation(s)
- Wing-Kee Lee
- Dept. of Physiology & Pathophysiology, Univ. of Witten/Herdecke, Faculty of Medicine, D-58448 Witten, Germany
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50
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Xing LX, Shen HT, Li YH, Wang JL, Yan X, Wang FR, Zhang XH. [Effects of fumonisin on HLA-I expression on human peripheral blood mononuclear cells in vitro]. Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi 2007; 23:794-6. [PMID: 17825220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
AIM To study the effects of Fumonisin B1(FB1) on HLA-I on human peripheral blood mononuclear cells (PBMC) in vitro. METHODS The expression of HLA-I on PBMC by FB1 pretreatment at different dosage(10, 50 micromol/L) was detected with flow cytometry (FCM), Western blot, and semi-RT-PCR, respectively. RESULTS The expression of HLA-I on PBMC in vitro at the two experimental concentration was both lower than that of the control after FB1 treatment for 24 h as represented by fluorescence intensity by FCM analysis. Western blot results further confirmed the above results. At mRNA level, HLA-A, B and C mRNA were detected by RT-PCR, and the results showed that no changes were found on the expression of HLA-A, B mRNA between FB1 treated group and the control group, but HLA-C mRNA was inhibited in FB1 treated groups. CONCLUSION 10 and 50 micromol/L FB1 could inhibit the expression of HLA-I on human PBMC in vitro at 24 h treatment.
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Affiliation(s)
- Ling-xiao Xing
- Lab of Experimental Pathology, Hebei Medical University, Shijiazhuang 050017, China.
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