Nitric oxide mediates positive regulation of Nostoc flagelliforme polysaccharide yield via potential S-nitrosylation of G6PDH and UGDH
Ontology highlight
ABSTRACT:
SUBMITTER: Li M
PROVIDER: S-EPMC11342573 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Nostoc flagelliforme Genome sequencing and assembly
| PRJNA848640 | ENA
Project description:ObjectiveDihydrofolate reductase (DHFR) is a key protein involved in tetrahydrobiopterin (BH4) regeneration from 7,8-dihydrobiopterin (BH2). Dysfunctional DHFR may induce endothelial nitric oxide (NO) synthase (eNOS) uncoupling resulting in enzyme production of superoxide anions instead of NO. The mechanism by which DHFR is regulated is unknown. Here, we investigate whether eNOS-derived NO maintains DHFR stability.Approach and resultsDHFR activity, BH4 content, eNOS activity, and S-nitrosylation were assessed in human umbilical vein endothelial cells and in aortas isolated from wild-type and eNOS knockout mice. In human umbilical vein endothelial cells, depletion of intracellular NO by transfection with eNOS-specific siRNA or by the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO)-both of which had no effect on DHFR mRNA levels-markedly reduced DHFR protein levels in parallel with increased DHFR polyubiquitination. Supplementation of S-nitroso-l-glutathione (GSNO), a NO donor, or MG132, a potent inhibitor of the 26S proteasome, prevented eNOS silencing and PTIO-induced DHFR reduction in human umbilical vein endothelial cells. PTIO suppressed S-nitrosylation of DHFR, whereas GSNO promoted DHFR S-nitrosylation. Mutational analysis confirmed that cysteine 7 of DHFR was S-nitrosylated. Cysteine 7 S-nitrosylation stabilized DHFR from ubiquitination and degradation. Experiments performed in aortas confirmed that PTIO or eNOS deficiency reduces endothelial DHFR, which can be abolished by MG132 supplementation.ConclusionsWe conclude that S-nitrosylation of DHFR at cysteine 7 by eNOS-derived NO is crucial for DHFR stability. We also conclude that NO-induced stabilization of DHFR prevents eNOS uncoupling via regeneration of BH4, an essential eNOS cofactor.
| S-EPMC4758687 | biostudies-literature
Project description:The GTPase dynamin regulates endocytic vesicle budding from the plasma membrane, but the molecular mechanisms involved remain incompletely understood. We report that dynamin, which interacts with NO synthase, is S-nitrosylated at a single cysteine residue (C607) after stimulation of the beta(2) adrenergic receptor. S-nitrosylation increases dynamin self-assembly and GTPase activity and facilitates its redistribution to the membrane. A mutant protein bearing a C607A substitution does not self-assemble properly or increase its enzymatic activity in response to NO. In NO-generating cells, expression of dynamin C607A, like the GTPase-deficient dominant-negative K44A dynamin, inhibits both beta(2) adrenergic receptor internalization and bacterial invasion. Furthermore, exogenous or endogenously produced NO enhances internalization of both beta(2) adrenergic and epidermal growth factor receptors. Thus, NO regulates endocytic vesicle budding by S-nitrosylation of dynamin. Collectively, our data suggest a general NO-dependent mechanism by which the trafficking of receptors may be regulated and raise the idea that pathogenic microbes and viruses may induce S-nitrosylation of dynamin to facilitate cellular entry.
| S-EPMC1360548 | biostudies-literature
Project description:Nitric oxide (NO) possesses antiinflammatory effects, which may be exerted via its ability to inhibit the transcription factor, NF-kappaB. A commonly proposed mode of action for inhibition of NF-kappaBbyNO involves interference with NF-kappaB binding to DNA. Because activation of inhibitory kappaB kinase (IKK), the prerequisite enzyme complex necessary to induce NF-kappaB, is subject to redox regulation, we assessed whether IKK could present a more proximal target for NO to inhibit NF-kappaB activation. We demonstrate here that S-nitrosothiols (SNO) caused a dose-dependent inhibition of the enzymatic activity of IKK, in lung epithelial cells and in Jurkat T cells, which was associated with S-nitrosylation of the IKK complex. Using biotin derivatization of SNO, we revealed that IKKbeta, the catalytic subunit required for NF-kappaB activation, was a direct target for S-nitrosylation. A mutant version of IKKbeta containing a Cys-179-to-Ala mutation was refractory to inhibition by SNO or to increases in S-nitrosylation, in contrast to wild-type IKKbeta, demonstrating that Cys-179 is the main target for attack by SNO. Importantly, inhibition of NO synthase activity in Jurkat T cells resulted in activation of IKK, in association with its denitrosylation. Moreover, NO synthase inhibition enhanced the ability of tumor necrosis factor alpha to activate IKK, illustrating the importance of endogenous NO in regulating the extent of NF-kappaB activation by cytokines. Collectively, our findings demonstrate that IKKbeta is an important target for the redox regulation of NF-kappaB by endogenous or exogenous NO, providing an additional mechanism for its antiinflammatory properties.
| S-EPMC428452 | biostudies-literature
Project description:To significantly improve the polysaccharide production of Nostoc flagelliforme, a total of 12 chemicals were evaluated for their effects on polysaccharide accumulation. The results showed that salicylic acid and jasmonic acid increased the accumulation of the polysaccharides in N. flagelliforme significantly, by more than 20%. Three polysaccharides, namely control-capsule polysaccharide, salicylic acid-capsule polysaccharide, and jasmonic acid-capsule polysaccharide, were extracted and purified from N. flagelliforme under normal, salicylic acid, and jasmonic acid culture conditions, respectively. Their chemical compositions slightly differed regarding the total sugar and uronic acid contents, with average molecular weights of 2.06 × 103, 2.16 × 103 and 2.04 × 103 kDa, respectively. They presented similar Fourier transform infrared spectra and no significant difference in antioxidant activity. It was revealed that the salicylic acid and jasmonic acid significantly increased the level of nitric oxide. By investigating the effects of the exogenous nitric oxide scavenger and nitric oxide donor on the nitric oxide levels and polysaccharide yield of N. flagelliforme, the results showed that the increase in intracellular nitric oxide levels might be an important factor promoting the accumulation of polysaccharides. These findings provide a theoretical foundation for enhancing the yield of secondary metabolites by regulating the intracellular nitric oxide levels.
| S-EPMC10001311 | biostudies-literature
Project description:The mass spectrometry-based metabolomics approach has become a powerful tool for the quantitative analysis of small-molecule metabolites in biological samples. Nostoc flagelliforme, an edible cyanobacterium with herbal value, serves as an unexploited bioresource for small molecules. In natural environments, N. flagelliforme undergoes repeated cycles of rehydration and dehydration, which are interrupted by either long- or short-term dormancy. In this study, we performed an untargeted metabolite profiling of N. flagelliforme samples at three physiological states: Dormant (S1), physiologically fully recovered after rehydration (S2), and physiologically partially inhibited following dehydration (S3). Significant metabolome differences were identified based on the OPLS-DA (orthogonal projections to latent structures discriminant analysis) model. In total, 183 differential metabolites (95 up-regulated; 88 down-regulated) were found during the rehydration process (S2 vs. S1), and 130 (seven up-regulated; 123 down-regulated) during the dehydration process (S3 vs. S2). Thus, it seemed that the metabolites' biosynthesis mainly took place in the rehydration process while the degradation or possible conversion occurred in the dehydration process. In addition, lipid profile differences were particularly prominent, implying profound membrane phase changes during the rehydration-dehydration cycle. In general, this study expands our understanding of the metabolite dynamics in N. flagelliforme and provides biotechnological clues for achieving the efficient production of those metabolites with medical potential.
| S-EPMC6562405 | biostudies-literature
Project description:Nitric oxide (NO) is a signaling intermediate during glutamatergic neurotransmission in the central nervous system (CNS). NO signaling is in part accomplished through cysteine S-nitrosylation, a posttranslational modification by which NO regulates protein function and signaling. In our investigation of the protein targets and functional impact of S-nitrosylation in the CNS under physiological conditions, we identified 269 S-nitrosocysteine residues in 136 proteins in the wild-type mouse brain. The number of sites was significantly reduced in the brains of mice lacking endothelial nitric oxide synthase (eNOS(-/-)) or neuronal nitric oxide synthase (nNOS(-/-)). In particular, nNOS(-/-) animals showed decreased S-nitrosylation of proteins that participate in the glutamate/glutamine cycle, a metabolic process by which synaptic glutamate is recycled or oxidized to provide energy. (15)N-glutamine-based metabolomic profiling and enzymatic activity assays indicated that brain extracts from nNOS(-/-) mice converted less glutamate to glutamine and oxidized more glutamate than those from mice of the other genotypes. GLT1 [also known as EAAT2 (excitatory amino acid transporter 2)], a glutamate transporter in astrocytes, was S-nitrosylated at Cys(373) and Cys(561) in wild-type and eNOS(-/-) mice, but not in nNOS(-/-) mice. A form of rat GLT1 that could not be S-nitrosylated at the equivalent sites had increased glutamate uptake compared to wild-type GLT1 in cells exposed to an S-nitrosylating agent. Thus, NO modulates glutamatergic neurotransmission through the selective, nNOS-dependent S-nitrosylation of proteins that govern glutamate transport and metabolism.
| S-EPMC4746709 | biostudies-literature