Dataset Information

Cadmium Disrupts the Balance between Hydrogen Peroxide and Superoxide Radical by Regulating Endogenous Hydrogen Sulfide in the Root Tip of Brassica rapa.

ABSTRACT: Cd (cadmium) stress always alters the homeostasis of ROS (reactive oxygen species) including H₂O₂ (hydrogen sulfide) and [Formula: see text] (superoxide radical), leading to the oxidative injury and growth inhibition in plants. In addition to triggering oxidative injury, ROS has been suggested as important regulators modulating root elongation. However, whether and how Cd stress induces the inhibition of root elongation by differentially regulating endogenous H₂O₂ and [Formula: see text], rather than by inducing oxidative injury, remains elusive. To address these gaps, histochemical, physiological, and biochemical approaches were applied to investigate the mechanism for Cd to fine-tune the balance between H₂O₂ and [Formula: see text] in the root tip of Brassica rapa. Treatment with Cd at 4 and 16 ?M significantly inhibited root elongation, while only 16 ?M but not 4 ?M of Cd induced oxidative injury and cell death in root tip. Fluorescent and pharmaceutical tests suggested that H₂O₂ and [Formula: see text] played negative and positive roles, respectively, in the regulation of root elongation in the presence of Cd (4 ?M) or not. Treatment with Cd at 4 ?M led to the increase in H₂O₂ and the decrease in [Formula: see text] in root tip, which may be attributed to the up-regulation of Br_UPB1s and the down-regulation of their predicted targets (four peroxidase genes). Cd at 4 ?M resulted in the increase in endogenous H₂S in root tip by inducing the up-regulation of LCDs and DCDs. Treatment with H₂S biosynthesis inhibitor or H₂S scavenger significantly blocked Cd (4 ?M)-induced increase in endogenous H₂S level, coinciding with the recovery of root elongation, the altered balance between H₂O₂ and [Formula: see text], and the expression of Br_UPB1s and two peroxidase genes. Taken together, it can be proposed that endogenous H₂S mediated the phytotoxicity of Cd at low concentration by regulating Br_UPB1s-modulated balance between H₂O₂ and [Formula: see text] in root tip. Such findings shed new light on the regulatory role of endogenous H₂S in plant adaptions to Cd stress.

SUBMITTER: Lv W

PROVIDER: S-EPMC5318417 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Cadmium Disrupts the Balance between Hydrogen Peroxide and Superoxide Radical by Regulating Endogenous Hydrogen Sulfide in the Root Tip of Brassica rapa.

Lv Wenjing W Yang Lifei L Xu Cunfa C Shi Zhiqi Z Shao Jinsong J Xian Ming M Chen Jian J

Frontiers in plant science 20170221

Cd (cadmium) stress always alters the homeostasis of ROS (reactive oxygen species) including H2O2 (hydrogen sulfide) and [Formula: see text] (superoxide radical), leading to the oxidative injury and growth inhibition in plants. In addition to triggering oxidative injury, ROS has been suggested as important regulators modulating root elongation. However, whether and how Cd stress induces the inhibition of root elongation by differentially regulating endogenous H2O ...[more]

PMID: 28270829

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Project description:Protein post-translational modification (PTM) is an efficient biological mechanism to regulate protein structure and function, but its role in plant responses to heavy metal stress is poorly understood. The present study performed quantitative succinyl-proteome profiling using liquid chromatography−mass spectrometry analysis to explore the potential roles of lysine succinylation modification in turnip seedlings in response to cadmium (Cd) stress (20 μM) under hydroponic conditions over a short time period (0−8 h). A total of 547 succinylated sites on 256 proteins were identified in the shoots of turnip seedlings. These succinylated proteins participated in various biological processes (e.g., photosynthesis, tricarboxylic acid cycle, amino acid metabolism, and response to stimulation) that occurred in diverse cellular compartments according to the functional classification, subcellular localization, and protein interaction network analysis. Quantitative analysis showed that the intensities of nine succinylation sites on eight proteins were significantly altered (p < 0.05) in turnip shoots after 8 h of Cd stress. These differentially succinylated sites were highly conserved in Brassicaceae species and mostly located in the conserved domains of the proteins. Among them, a downregulated succinylation site (K150) in the glycolate oxidase protein (Gene0282600.1), an upregulated succinylation site (K396) in the catalase 3 protein (Gene0163880.1), and a downregulated succinylation site (K197) in the glutathione S-transferase protein (Gene0315380.1) may have contributed to the altered activity of the corresponding enzymes, which suggests that lysine succinylation affects the Cd detoxification process in turnip by regulating the H2O2 accumulation and glutathione metabolism. These results provide novel insights into understanding Cd response mechanisms in plants and important protein modification information for the molecular-assisted breeding of Brassica varieties with distinct Cd tolerance and accumulation capacities.

Project description:The deacetylase SIRT1 (sirtuin 1) has emerged as a major regulator of nucleocytoplasmic distribution of macroautophagy/autophagy marker MAP1LC3/LC3 (microtubule-associated protein 1 light chain 3). Activation of SIRT1 leads to the deacetylation of LC3 and its translocation from the nucleus into the cytoplasm leading to an increase in the autophagy flux. Notably, hydrogen sulfide (H2S) is a cytoprotective gasotransmitter known to activate SIRT1 and autophagy; however, the underlying mechanism for both remains unknown. Herein, we demonstrate that H2S sulfhydrates the active site cysteine of the glycolytic enzyme GAPDH (glyceraldehyde-3-phosphate dehydrogenase). Sulfhydration of GAPDH leads to its redistribution into the nucleus. Importantly, nuclear localization of GAPDH is critical for H2S-mediated activation of autophagy as H2S does not induce autophagy in cells with GAPDH ablation or cells overexpressing a GAPDH mutant lacking the active site cysteine. Importantly, we observed that nuclear GAPDH interacts with CCAR2/DBC1 (cell cycle activator a nd apoptosis regulator 2) inside the nucleus. CCAR2 interacts with the deacetylase SIRT1 to inhibit its activity. Interaction of GAPDH with CCAR2 disrupts the inhibitory effect of CCAR2 on SIRT1. Activated SIRT1 then deacetylates MAP1LC3B/LC3B (microtubule-associated protein 1 light chain 3 beta) to induce its translocation into the cytoplasm and activate autophagy. Additionally, we demonstrate this pathway's physiological role in autophagy-mediated trafficking of Mycobacterium tuberculosis into lysosomes to restrict intracellular mycobacteria growth. We think that the pathway described here could be involved in H2S-mediated clearance of intracellular pathogens and other health benefits.Abbreviations: ATG5: autophagy related 5; ATG7: autophagy related 7; BECN1: beclin 1, autophagy related; CCAR2/DBC1: cell cycle activator and apoptosis regulator 2; CFU: colony-forming units; DLG4/PSD95: discs large MAGUK scaffold protein 4; EX-527: 6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; H2S: hydrogen sulfide; HEK: human embryonic kidney cells; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MEF: mouse embryonic fibroblast; Mtb: Mycobacterium tuberculosis; MTOR: mechanistic target of rapamycin kinase; MOI: multiplicity of infection; NO: nitric oxide; PI3K: phosphatidylinositol-4,5-bisphosphate 3-kinase; PLA: proximity ligation assay; PRKAA: protein kinase, AMP-activated, alpha catalytic subunit; SIAH1: siah E3 ubiquitin protein ligase 1A; SIRT1: sirtuin 1; TB: tuberculosis; TP53INP2/DOR: transformation related protein 53 inducible nuclear protein 2; TRP53/TP53: transformation related protein 53.

Dataset Information

Cadmium Disrupts the Balance between Hydrogen Peroxide and Superoxide Radical by Regulating Endogenous Hydrogen Sulfide in the Root Tip of Brassica rapa.

Publications

Cadmium Disrupts the Balance between Hydrogen Peroxide and Superoxide Radical by Regulating Endogenous Hydrogen Sulfide in the Root Tip of <i>Brassica rapa</i>.

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