Search Results (90)

Soil co-contamination with cadmium (Cd) and zinc (Zn) poses serious threats to environmental safety and public health. This study investigates the enhancement effect and underlying mechanism of the biodegradable chelator Ethylenediamine-N,N′-disuccinic acid (EDDS) on phytoremediation of Cd-Zn contaminated soil using Sedum lineare. The results demonstrate that EDDS application (3.65 g·L⁻¹) effectively alleviated metal-induced phytotoxicity by enhancing chlorophyll synthesis, activating antioxidant enzymes (catalase and dismutase), regulating S-nitrosoglutathione reductase activity, and promoting leaf protein synthesis, thereby improving photosynthetic performance and cellular integrity. The combined treatment significantly increased the bioavailability of Cd and Zn in soil, promoted their transformation into exchangeable fraction, and resulted in removal rates of 30.8% and 28.9%, respectively. EDDS also modified the interaction patterns between heavy metals and essential nutrients, particularly the competitive relationships through selective chelation between Cd/Zn and Fe/Mn during plant uptake. Soil health was substantially improved, as evidenced by reduced electrical conductivity, enhanced cation exchange capacity, and enriched beneficial microbial communities including Sphingomonadaceae. Based on the observed ion antagonism during metal uptake and translocation, this study proposes a novel “Nutrient Regulation Assisted Remediation” strategy to optimize heavy metal accumulation and improve remediation efficiency through rhizosphere nutrient management. These findings confirm the EDDS–S. lineare system as an efficient and sustainable solution for remediation of Cd–Zn co-contaminated soils. Full article

Background/Objectives: Preterm infants are at risk of developing the chronic lung condition of bronchopulmonary dysplasia (BPD), with associated alveolar simplification and airway hyperreactivity. Inhibition of S-nitrosoglutathione (GSNO) reductase has been shown to rescue airway hyperreactivity in a murine model of BPD. Here, we investigate the effects of early treatment with N6022, a pharmacologic GSNO reductase inhibitor. Methods: Newborn C57BL/6 mice were exposed to either 21% (control) or 60% oxygen (BPD model) for 5 days after birth. Pups simultaneously received either subcutaneous saline or varying doses of N6022 for 5 days during hyperoxia exposure. Pups were then recovered in room air to 3 weeks postnatal age. H&E-stained lungs were analyzed for alveolar simplification and airway tethering. In vivo airway reactivity to inhaled methacholine was measured using a flexiVent system. In separate littermates, lungs were immediately harvested after 5 days of hyperoxia for protein quantification via automated capillary Westerns. Results: Alveolar simplification and decreased airway tethering were noted in the 60% + saline group. Pups treated with N6022 during hyperoxia displayed dose-dependent improvements in alveolar simplification and airway tethering. Similarly, hyperoxia-exposed pups had increased airway reactivity, as measured by elevated respiratory system resistance and elastance responses to methacholine. Treatment with 10 mg/kg/day N6022 during hyperoxia resulted in decreased resistance and elastance responses. TGF-β expressions were elevated in the 60% + saline group and attenuated in the 60% + N6022 groups. Conclusions: Early exposure to GSNO reductase inhibitors such as N6022 can prevent hyperoxia-induced alveolar simplification and airway hyperreactivity, with lasting effects even after cessation of treatment. Full article

Background: Cutaneous wound infections caused by methicillin-resistant Staphylococcus aureus (MRSA) pose serious threats to public health. Nitric oxide (NO), an endogenous gaseous molecule with antibacterial and wound-healing properties, is a promising next-generation antimicrobial agent with a minimal risk of resistance. However, conventional S-nitrosoglutathione (GSNO)-loaded formulations suffer from GSNO leakage, which could compromise the treatment effect or induce systemic side effects. Although conjugation strategies have been introduced to mitigate this issue, there is still a lack of GSNO-conjugated systems that simultaneously achieve high NO loading and sustained NO release while avoiding harsh external stimuli and complex multistep synthetic processes. Objectives: This research aims to develop a high NO-loading system produced through a simple synthetic process that provides sustained NO release without harsh external stimuli while preventing GSNO leakage for effective treatment of MRSA-infected wounds. Methods: We developed cellulose-based GSNO conjugates via a simple EDC/NHS-mediated covalent coupling to TEMPO-oxidized nanocellulose (NC-GSNO). Results: The NC-GSNO hydrogel achieved high NO loading, minimal leakage, and sustained NO release for more than three days. This controlled NO delivery promoted enhanced wound healing in MRSA-infected models. Conclusions: These findings demonstrate that the NC-GSNO hydrogel is a promising platform for controlled NO delivery and the effective treatment of MRSA-infected wounds. Full article

S-nitrosoglutathione (GSNO) reductase (GSNOR) is a major and conserved enzyme in prokaryotes and eukaryotes. It reduces a stable nitric oxide (NO) reservoir, GSNO, to balance the organisms’ redox status through S-nitrosylation. Over the last few decades, much of our understanding of GSNOR’s roles in plant biology has been updated. Here, therefore, we review the current knowledge of GSNOR in plant physiology and signaling under abiotic and biotic stresses. We observe that the role of GSNOR in plant abiotic stress is widely studied in both model and crop plants, whereas studies on its role in biotic stress have mainly focused on model plants. Under abiotic stresses, GSNOR plays a pleiotropic role in terms of plant tolerance and sensitivity. The presence or absence of GSNOR activity modulates the endogenous NO pool that balances plant reactive nitrogen species (RNS) and reactive oxygen species (ROS) under stress conditions. Moreover, GSNOR regulates hormonal levels, like ethylene, abscisic acid (ABA), jasmonic acid (JA), and salicylic acid (SA), in response to abiotic and biotic stress conditions. Although GSNOR is important in plant physiology, its regulation of the redox switch is directly influenced by the extent of S-nitrosylation, where S-nitrosylated proteins generally enhance plant tolerance to abiotic stress but simultaneously suppress plant immunity. We further highlight a new perspective on NO-based nanotechnology in agriculture, focusing on GSNO encapsulated in nanocarriers. This technology improves NO stability and opens new avenues by allowing an evaluation of GSNOR’s role for sustainable crop production. Intriguingly, we discuss knowledge gaps, which are crucial to understanding the role of GSNOR in plant stress tolerance. Overall, this review accumulates a comprehensive understanding of the GSNOR enzyme in crop biology, which could aid in harnessing its function to address the impacts of climate change. Full article

Cystathionine γ-lyase (CSE) is a pyridoxal 5′-phosphate (PLP)-dependent enzyme that catalyzes the final step of the transsulfuration pathway, converting cystathionine into cysteine. Additionally, CSE is also essential for the formation of cysteine hydropolysulfide (Cys-S-(S)n-H), known as supersulfides, by metabolizing cystine under pathological conditions. We previously reported that, during cystine metabolism, CSE undergoes self-inactivation through polysulfidation at the Cys136 residue. Here, contrary to the anticipated role of L-S-nitrosocysteine (L-CysNO) as a nitric oxide (NO) donor, we demonstrate that it serves as a substrate for CSE and that its metabolites inhibit the activity of the enzyme during L-CysNO metabolism. The in vitro incubation of CSE—but not the Cys136/171Val mutant—with L-CysNO resulted in the dose-dependent inhibition of supersulfide production, which was not reversed by the reducing agents. Notably, CSE activity remained unchanged upon preincubation with other NO donors, such as S-nitrosoglutathione or D-CysNO, but was inhibited when coincubated with cysteine. Furthermore, when PLP was removed from the CSE/L-CysNO premix, L-CysNO no longer inhibited CSE activity, suggesting that CSE metabolizes L-CysNO and that its metabolites contribute to enzyme inactivation. Indeed, we identified thionitrous acid and pyruvate as the primary CSE/L-CysNO reaction products. Thus, we establish L-CysNO as a CSE substrate and demonstrate that its metabolites act as enzyme inhibitors through a novel irreversible modification at the Cys136/171 residues. Full article

Nitric oxide is a gaseous signalling molecule produced by plants. Slight changes in endogenous NO levels have significant biochemical and physiological consequences. We investigated the structural and functional properties of NO-responsive antiporter genes in Arabidopsis thaliana. Phylogenetic analysis of 50 antiporter genes classified them into four subgroups based on the presence of NHX and CPA domains and the evolutionary similarity of the protein sequences. Antiporters were found scattered across the five chromosomes with unique physico-chemical properties and subcellular localisation in the plasma membrane, nucleus, chloroplasts, and vacuole. Furthermore, we performed QPCR analysis of eight different antiporter genes after infiltrating the plants with 1 mM CySNO (S-nitroso-L-cysteine), a nitric oxide donor, in WT and the loss-of-function atgsnor1-3 (disruptive S-nitrosoglutathione reductase 1 activity) plants. The AT1G79400 (CHX2), AT2G38170 (RCI4), and AT5G17400 (ER-ANT1) showed a significant increase in their expression in response to CySNO infiltration. However, their expression in atgsnor1-3 plants was found to be lower than in the WT plants, indicating a significant redundancy in the response of these genes to 1 mM levels of CySNO and physiological levels of SNOs in atgsnor1-3. On the other hand, a significant reduction in the expression of AT1G16380 (CHX1), AT2G47600 (MHX1), AT3G13320 (CAX2), and AT5G11800 (KEA6) was observed in WT plants after CySNO infiltration as well as in the leaves of atgsnor1-3 plants. Our study identified three NO-responsive antiporter genes in Arabidopsis, indicating their roles in stress responsiveness and ion homeostasis that could be used for further validation of their roles in NO signalling in plants. Full article

S-nitrosoglutathione (GSNO), a promising S-nitrosothiol, has been recognized for its ability to modulate vascular tone through its vasodilatory, antiplatelet, and antiproliferative effects. However, data on its vasodilatory effects in human vessels remain limited, and its mechanisms of action have yet to be fully elucidated. In this study, we aimed to investigate the vasorelaxant effect of GSNO and its underlying mechanisms, with particular focus on the soluble guanylate cyclase (sGC)/nitric oxide (NO) pathway and potassium channels in isolated human saphenous veins (SVs) obtained from patients undergoing coronary artery bypass grafting (CABG). GSNO (10⁻⁸–10⁻⁴ M) produced concentration-dependent relaxations in SV rings precontracted with phenylephrine. These relaxations were unaffected by NO synthase inhibition with L-NAME (10⁻⁴ M, 30 min) or NO scavenging with PTIO (10⁻⁴ M, 30 min), but were significantly reduced by the sGC inhibitor, ODQ (10⁻⁵ M, 30 min). Inhibition of ATP-sensitive (glibenclamid; 10⁻⁵ M, 30 min.), high-conductance Ca²⁺-activated (charybdotoxin; 10⁻⁷ M, 30 min), small-conductance Ca²⁺-activated (apamin; 10⁻⁶ M, 30 min), or voltage-dependent (4-aminopyridine; 10⁻³ M, 30 min) potassium channels did not alter the maximum relaxant responses to GSNO. Furthermore, pretreatment with GSNO (10⁻⁴ M, 30 min) significantly attenuated both the contractile response and sensitivity to phenylephrine. Collectively, these findings demonstrate that GSNO exerts acute vasorelaxant and modulatory effects in human SV primarily via cGMP-dependent mechanisms, highlighting its potential as a local therapeutic agent for preventing graft spasm in CABG. Full article

Nitric oxide (NO) is an endogenous signaling molecule that plays a critical role in wound healing. However, the gaseous nature, short half-life, and low stability of NO present challenges for its clinical application. To address these issues, this study introduces an innovative S-nitrosoglutathione (GSNO)-loaded asymmetric alginate (SA) hydrogel (GSNO-SA) as a novel solution for treating infected chronic wounds. The hydrogel is designed with a layer-by-layer melting-permeation crosslinking approach, forming a dense upper layer and a sparse lower layer structure, effectively promoting exudate management while delaying NO release. The results demonstrate that the GSNO-SA hydrogel extends NO release for up to 48 h, exhibits rapid exudate absorption (72.3 ± 1.5% equilibrium swelling after 5 min), significant antibacterial activity (over 90% antibacterial rate against E. coli and S. aureus), and anti-inflammatory effects (marked reduction in TNF-α expression), and promotes angiogenesis (90.00 ± 5.92% migration rate at 48 h). Additionally, animal studies show that the GSNO-SA hydrogel accelerates wound healing, achieving a 99.2 ± 0.1% closure rate at 14 days. Histological and immunohistochemical evaluations further confirm its ability to regulate inflammation (13.34-fold upregulation of CD163) and promote angiogenesis (3.02-fold upregulation of α-SMA). Theoretically, this asymmetric design provides a novel strategy for developing exudate-managing dressings by integrating controlled NO release with hierarchical pore structures. Full article

S-nitrosoglutathione (GSNO) is the S-nitrosated derivative of glutathione (GSH). GSNO is an endogenous class of NO donors and a natural NO depot in biological systems. Organic anion transporting polypeptide 1B1 (OATP1B1) is an influx transporter that is expressed in the liver. OATP1B1 plays an important role in the transport of endogenous and exogenous substances. Various pathways for the regulation of OATP1B1 have been described. In the present study, the involvement of OATP1B1 in GSNO transport and the regulation of OATP1B1 by GSNO was examined. For HEK293-OATP1B1, it has been shown that GSNO is not a substrate of OATP1B1, but OATP1B1 can participate in the transport of GSH across the cell membrane. GSNO at concentrations of 1–100 μM and exposure for 3 h do not affect the expression and activity of OATP1B1, but exposure for 24 and 72 h stimulates the expression of the SLCO1B1 gene, OATP1B1, and transporter activity. Up-regulation of OATP1B1 by GSNO is carried out through the NO-cGMP signaling pathway, Nrf2, and LXRa. Full article

Background: O⁶-Methylguanine-DNA methyltransferase (MGMT) is a unique antimutagenic DNA repair protein that plays a crucial role in conferring resistance to various alkylating agents in brain tumor therapy. In this study, we exploited the susceptibility of the active site Cys145 of MGMT for thiolation and nitrosylation, both of which inactivate the enzyme. Methods: We designed a redox perturbing glutathione mimetic, a platinated homoglutathione disulfide (hGTX) by adding small amounts of cisplatin (1000:10) and used a nitric oxide-donor spermine NONOate. N6022, a potent inhibitor of S-nitrosoglutathione reductase was used to extend the retention of nitrosylated MGMT in tumor cell culture and subcutaneous xenografts. Results: Both hGTX and spermine NONOate inhibited MGMT activity in HT29, SF188, T98G, and other brain tumor cells. There was a robust increase in the alkylation-induced DNA interstrand cross-linking, G2/M cell cycle arrest, cytotoxicity, and the levels of apoptotic markers when either of the agents was used with alkylating agents. In the nude mice bearing T98G and HT29-luc2 xenografts, combinations of hGTX and spermine NONOate with alkylating agents produced a marked reduction in MGMT protein and tumor growth delay and regressions. N6022 treatment increased the presence of nitrosylated MGMT for a longer time, thereby extending the DNA-repair deficient state both in cell culture and preclinical settings. Conclusions: Our findings highlight the options for redox-driven therapeutic strategies for MGMT and suggest that oxidative and/or nitrosative inactivation of DNA repair in combination with alkylating agents could be exploited. Full article

Nitric oxide (NO) is a multifunctional signaling molecule in plants, playing key roles in germination, microbial symbiosis, and nodule formation. However, its instability requires innovative approaches, such as using nanoencapsulated NO donors, to prolong its effects. This study evaluated the impact of treating soybean (Glycine max) seeds with the NO donor S-nitrosoglutathione (GSNO), encapsulated in polymeric nanoparticles, on the germination, nodulation, and plant growth. Seeds were treated with free GSNO, chitosan nanoparticles with/without NO (NP CS-GSNO/NP CS-GSH, where GSH is glutathione, the NO donor precursor), and alginate nanoparticles with/without NO (NP Al-GSNO/NP Al-GSH). Chitosan nanoparticles (positive zeta potential) were smaller and released NO faster compared with alginate nanoparticles (negative zeta potential). The seed treatment with NP CS-GSNO (1 mM, related to GSNO concentration) significantly improved germination percentage, root length, number of secondary roots, and dry root mass of soybean compared with the control. Conversely, NP CS-GSH resulted in decreased root and shoot length. NP Al-GSNO enhanced shoot dry mass and increased the number of secondary roots by approximately threefold at the highest concentrations. NP CS-GSNO, NP Al-GSNO, and NP Al-GSH increased S-nitrosothiol levels in the roots by approximately fourfold compared with the control. However, NP CS-GSNO was the only treatment that increased the nodule dry mass of soybean plants. Therefore, our results indicate the potential of chitosan nanoparticles to improve the application of NO donors in soybean seeds. Full article

Nitrogen fixation in legume nodules is crucial for plant growth and development. Therefore, this study aims to investigate the effects of nitric oxide [S-nitrosoglutathione (GSNO)] and silicon [sodium metasilicate (Si)], both individually and in combination, on soybean growth, nodule formation, leghaemoglobin (Lb) synthesis, and potential post-translational modifications. At the V1 stage, soybean plants were treated for 2 weeks with 150 µM GSNO, and Si at concentrations of 1 mM, 2 mM, and 4 mM. The results showed that NO and Si enhance the nodulation process by increasing phenylalanine ammonia-lyase activity and Nod factors (NIP2-1), attracting rhizobia and accelerating nodule formation. This leads to a greater number and larger diameter of nodules. Individually, NO and Si support the synthesis of Lb and leghaemoglobin protein (Lba) expression, ferric leghaemoglobin reductases (FLbRs), and S-nitrosoglutathione reductase (GSNOR). However, when used in combination, NO and Si inhibit these processes, leading to elevated levels of S-nitrosothiols in the roots and nodules. This combined inhibition may potentially induce post-translational modifications in FLbRs, pivotal for the reduction of Lb³⁺ to Lb²⁺. These findings underscore the critical role of NO and Si in the nodulation process and provide insight into their combined effects on this essential plant function. Full article

Nitric oxide (NO) has been firmly established as a key signaling molecule in plants, playing a significant role in regulating growth, development and stress responses. Given the imperative of sustainable agriculture and the urgent need to meet the escalating global demand for food, it is imperative to safeguard crop plants from the effects of climate fluctuations. Plants respond to environmental challenges by producing redox molecules, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), which regulate cellular, physiological, and molecular processes. Nitric oxide (NO) plays a crucial role in plant stress tolerance, acting as a signaling molecule or free radical. NO is involved in various developmental processes in plants through diverse mechanisms. Exogenous NO supplementation can alleviate the toxicity of abiotic stresses and enhance plant resistance. In this review we summarize the studies regarding the production of NO in peroxisomes, and how its molecule and its derived products, (ONOO⁻) and S-nitrosoglutathione (GSNO) affect ROS metabolism in peroxisomes. Peroxisomal antioxidant enzymes including catalase (CAT), are key targets of NO-mediated post-translational modification (PTM) highlighting the dynamic metabolism of ROS and RNS in peroxisomes. Full article

Soybean, a major legume crop, has seen a decline in its production owing to challenges in seed germination and the development of seedlings. Thus, in this study, we systematically investigated the influence of various chitosan–S-nitrosoglutathione (chitosan-GSNO) nanoparticle (0, 25, 50, and 100 µM) and Si (0, 0.5, and 1 mM) priming concentrations on soybean seed germination and seedling growth over five different priming durations (range: 1–5 h at each concentration). Significant differences were observed in all parameters, except seedling diameter, with both treatments. Seed germination was significantly enhanced after 3 h of priming in both treatments. The final germination percentage (FGP), peak germination percentage (PGP), vigor index (VI), seedling biomass (SB), hypocotyl length (HL), and radical length (RL) of 100 μM chitosan-GSNO-nanoparticle-primed seeds increased by 20.3%, 41.3%, 78.9%, 25.2%, 15.7%, and 65.9%, respectively, compared with those of the control; however, the mean germination time (MGT) decreased by 18.43%. Si priming at 0.5 mM increased the FGP, PGP, VI, SB, HL, and RL by 13.9%, 55.17%, 39.2%, 6.5%, 22.5%, and 25.1%, respectively, but reduced the MGT by 12.29% compared with the control treatment. Chitosan-GSNO and Si treatment up-regulated the relative expression of gibberellic acid (GA)-related genes (GmGA3ox3 and GmGA2ox1) and down-regulated that of abscisic acid (ABA)-related genes (GmABA2, GmAAO3, and GmNCED5). Chitosan-GSNO and Si application increased bioactive GA₄ levels and simultaneously reduced ABA content. Hence, the use of exogenous chitosan-GSNO nanoparticles and Si as priming agents had a beneficial effect on seed germination and seedling growth because of the up-regulation in the expression of GA and down-regulation in the expression of ABA. Additional research is needed to understand the combined impact of Si and chitosan-GSNO nanoparticles, including their effects on the expression levels of other hormones and genes even in the later growth stage of the crop. Full article

Long-duration mission (LDM) astronauts from the International Space Station (ISS) (>180 ISS days) revealed a close-to-normal sarcolemmal nitric oxide synthase type-1 (NOS1) immunoexpression in myofibers together with biochemical and quantitative qPCR changes in deep calf soleus muscle. Nitro-DIGE analyses identified functional proteins (structural, metabolic, mitochondrial) that were over-nitrosylated post- vs. preflight. In a short-duration mission (SDM) astronaut (9 ISS days), s-nitrosylation of a nodal protein of the glycolytic flux, specific proteins in tricarboxylic acid (TCA) cycle, respiratory chain, and over-nitrosylation of creatine kinase M-types as signs of impaired ATP production and muscle contraction proteins were seen. S-nitrosylation of serotransferrin (TF) or carbonic anhydrase 3 (CA3b and 3c) represented signs of acute response microgravity muscle maladaptation. LDM nitrosoprofiles reflected recovery of mitochondrial activity, contraction proteins, and iron transporter TF as signs of muscle adaptation to microgravity. Nitrosated antioxidant proteins, alcohol dehydrogenase 5/S-nitrosoglutathione reductase (ADH5/GSNOR), and selenoprotein thioredoxin reductase 1 (TXNRD1) levels indicated signs of altered redox homeostasis and reduced protection from nitrosative stress in spaceflight. This work presents a novel spaceflight-generated dataset on s-nitrosylated muscle protein signatures from astronauts that helps both to better understand the structural and molecular networks associated to muscular nitrosative stress and to design countermeasures to dysfunction and impaired performance control in human spaceflight missions. Full article