Biochemical and Biophysical Research Communications
Nitric oxide: A cytotoxic activated macrophage effector molecule
The experiments reported here identify nitric oxide as a molecular effector of activated macrophage induced cytotoxicity. Cytotoxic activated macrophages synthesize nitric oxide from a terminal guanidino nitrogen atom of L-arginine which is converted to L-citrulline without loss of the guanidino carbon atom. In addition, authentic nitric oxide gas causes the same pattern of cytotoxicity in L10 hepatoma cells as is induced by cytotoxic activated macrophages (iron loss as well as inhibition of DNA synthesis, mitochondrial respiration, and aconitase activity). The results suggest that nitric oxide is the precursor of nitrite/nitrate synthesized by cytotoxic activated macrophages and, via formation of iron-nitric oxide complexes and subsequent degradation of iron-sulfur prosthetic groups, an effector molecule.
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Cited by (1941)
Phosphoinositide and redox dysregulation by the anticancer methylthioadenosine phosphorylase transition state inhibitor
2023, Biochimica et Biophysica Acta - Molecular and Cell Biology of LipidsMethylthio-DADMe-immucillin-A (MTDIA) is an 86 picomolar inhibitor of 5′-methylthioadenosine phosphorylase (MTAP) with potent and specific anti-cancer efficacy. MTAP salvages S-adenosylmethionine (SAM) from 5′-methylthioadenosine (MTA), a toxic metabolite produced during polyamine biosynthesis. Changes in MTAP expression are implicated in cancer growth and development, making MTAP an appealing target for anti-cancer therapeutics. Since SAM is involved in lipid metabolism, we hypothesised that MTDIA alters the lipidomes of MTDIA-treated cells. To identify these effects, we analysed the lipid profiles of MTDIA-treated Saccharomyces cerevisiae using ultra-high resolution accurate mass spectrometry (UHRAMS). MTAP inhibition by MTDIA, and knockout of the Meu1 gene that encodes for MTAP in yeast, caused global lipidomic changes and differential abundance of lipids involved in cell signaling. The phosphoinositide kinase/phosphatase signaling network was specifically impaired upon MTDIA treatment, and was independently validated and further characterised via altered localization of proteins integral to this network. Functional consequences of dysregulated lipid metabolism included a decrease in reactive oxygen species (ROS) levels induced by MTDIA that was contemporaneous with changes in immunological response factors (nitric oxide, tumour necrosis factor-alpha and interleukin-10) in mammalian cells. These results indicate that lipid homeostasis alterations and concomitant downstream effects may be associated with MTDIA mechanistic efficacy.
Bioactive glass in the treatment of ulcerative colitis to regulate the TLR4 / MyD88 / NF-κB pathway
2023, Biomaterials AdvancesUlcerative colitis (UC) is a chronic and recurrent intestinal disease of unknown aetiology, and the few treatments approved for UC have serious side effects. In this study, a new type of uniformly monodispersed calcium-enhanced radial mesoporous micro-nano bioactive glass (HCa-MBG) was prepared for UC treatment. We established cellular and rat UC models to explore the effects and mechanism of HCa-MBG and traditional BGs (45S5, 58S) on UC. The results showed that BGs significantly reduced the cellular expression of several inflammatory factors, such as IL-1β, IL-6, TNF-α and NO. In the animal experiments, BGs were shown to repair the DSS-damaged colonic mucosa. Moreover, BGs downregulated the mRNA levels of the inflammatory factors IL-1β, IL-6, TNF-α and iNOS, which were stimulated by DSS. BGs were also found to manage the expression of key proteins in NF-kB signal pathway. However, HCa-MBG was more effective than traditional BGs in terms of improving UC clinical manifestations and reducing the expression of inflammatory factors in rats. This study confirmed for the first time that BGs can be used as an adjuvant drug in UC treatment, thereby preventing UC progression.
Curative anti-typhoid effect of Detarium microcarpum Guill. & Perr. (Leguminosae) hydroethanolic extract root bark based-on in vivo and molecular docking analyses
2023, Journal of EthnopharmacologyDetarium microcarpum is used to treat typhoid fever, a major public health problem, by indigenous population in Africa. Though its preventive activities have been documented, the curative effect is still to be confirmed.
This study aimed at evaluating the curative effects of the hydroethanolic extract of Detarium microcarpum root bark on Salmonella typhimurium-induced typhoid in rat and exploring the in-silico inhibition of some bacterial key enzymes.
In vitro antioxydant, in vivo antisalmonella of the extract and in silico molecular docking assay on the isolated compounds were carried out to explore the anti-salmonella effects of Detarium microcarpum.
The in vitro antioxidant properties of the extract were evaluated using DPPH, ABTS and FRAP tests. The anti-salmonella activity of the extract was assessed through feacal sample from Salmonella typhimurium-infected rat cultured in Salmonella-Shigella agar (SS agar) medium. The affinity of isolated compounds (Rhinocerotinoic acid and Microcarposide) from the extract were performed on four key enzymes (Adenylosuccinate lyase, Acetyl coenzyme A synthetase, Thymidine phosphorylase and LuxS-Quorum sensor) using molecular docking simulation to elucidate the molecular level inhibition mechanism.
Crude extract of D. microcarpum root bark showed variable activities on DPPH (RSa50: 6.09 ± 1.04 μg/mL), ABTS (RSa50: 24.46 ± 0.27), and FRAP (RSa50: 23.30 ± 0.23). The extract at all the doses exhibited significant healing effect of infected rats, with the complete clearance. The extract restored hematological, biochemical and histological parameters closed to the normal control. The molecular docking results indicates that rhinocerotinoic acid and microcarposide present more affinity to the LuxS-Quorum sensor and Acetyl coenzyme A synthetase protein as compared to the others.
These results demonstrate potent anti-typhoid activities of the hydroethanolic of Detarium microcarpum root bark extract through antioxidant properties and high inhibitory affinity of its compounds on some bacterial key enzymes that justify its use as traditional medicine to typhoid fever.
Requirement of scavenger receptors for activation of the IRF-3/IFN-β/STAT-1 pathway in TLR4-mediated production of NO by LPS-activated macrophages
2023, Nitric Oxide - Biology and ChemistryProduction of nitric oxide (NO) by LPS-activated macrophages is due to a complex cellular signaling initiated by TLR4 that leads to the transcription of IFN-β, which activates IRF-1 and STAT-1, as well as to the activation of NF-κB, required for iNOS transcription. High concentrations of LPS can also be uptaken by scavenger receptors (SRs), which, in concert with TLR4, leads to inflammatory responses. The mechanisms by which TLR4 and SRs interact, and the pathways activated by this interaction in macrophages are not elucidated. Therefore, our main goal was to evaluate the role of SRs, particularly SR-A, in LPS-stimulated macrophages for NO production. We first showed that, surprisingly, LPS can induce the expression of iNOS and the production of NO in TLR4−/− mice, provided exogenous IFN-β is supplied. These results indicate that LPS stimulate receptors other than TLR4. The inhibition of SR-A using DSS or neutralizing antibody to SR-AI showed that SR-A is essential for the expression of iNOS and NO production in stimulation of TLR4 by LPS. The restoration of the ability to express iNOS and produce NO by addition of rIFN-β to inhibited SR-A cells indicated that the role of SR-AI in LPS-induced NO production is to provide IFN-β, probably by mediating the internalization of LPS/TLR4, and the differential inhibition by DSS and neutralizing antibody to SR-AI suggested that other SRs are also involved. Our results reinforce that TLR4 and SR-A act in concert in LPS activation and demonstrated that, for the production of NO, it does mainly by synthesizing IRF-3 and also by activating the TRIF/IRF-3 pathway for IFN-β production, essential for LPS-mediated transcription of iNOS. Consequently STAT-1 is activated, and IRF-1 is expressed, which together with NF-κB from TLR4/MyD88/TIRAP, induce iNOS synthesis and NO production.
TLR4 and SRs act in concert activating IRF-3 to transcribe IFN-β and activate STAT-1 to produce NO by LPS-activated macrophages.
The role of nitric oxide (NO) modulators in obsessive-compulsive disorder (OCD)
2023, Nitric Oxide - Biology and ChemistryObsessive-compulsive disorder (OCD) is as serious devastating anxiety disorder. Selective serotonin reuptake inhibitors (SSRIs) are largely used for the treatment of this mental disease. This pharmacological approach presents consistent limitations including modest efficacy and important side effects. There is pressing need, therefore, to develop new molecules with higher efficacy and safety. Nitric oxide (NO) is an intra-and inter-cellular messenger in the brain. Its involvement in the pathogenesis of OCD has been proposed. In a series of preclinical studies, the anxiolytic profile of NO modulators has been emerged. In the present review I intended to critically evaluate advances in research of these molecules as potential novel agents for the treatment of OCD, comment their advantages over currently used pharmacological therapy as well remaining challenges. Up to now, few preclinical studies have been carried out to this end. Nonetheless, experimental evidence proposes a role for NO and its modulators in OCD. Additional research is mandatory aiming to definitively determine a role for NO modulators for the treatment of OCD. A note of caution, however, is needed on account of potential neurotoxicity and narrow therapeutic window of NO compounds.
Nitrite is reduced by nitrite reductase NirB without small subunit NirD in Escherichia coli
2022, Journal of Bioscience and BioengineeringThe assimilatory nitrite reductase enzyme NirB and small subunit NirD genes encoded in nir operon in Escherichia coli were cloned into the pET28a vector, and the recombinant enzyme was characterized for the first time. Docking of NirB with NirD, NADH, NO2-, NO3-, and CHO2- was performed using docking modeling programs. Methyl viologen and sodium dithionite were used as electron couples, and the amount of reduced nitrite was measured to calculate enzyme activity. NirB is the main enzyme and shows high activity with or without NirD. However, the inclusion of NirD into the enzyme solution at a ratio of 1NirD:2NirB resulted in 10% higher nitrite reductase activity. The enzyme tends to aggregate in the absence of β-mercaptoethanol, which causes the conversion of tetrameric NirB to monomeric form, and the NirB enzyme shows its highest activity in monomeric form. The optimum temperature for enzyme activity was 37 °C and the optimum pH was found to be 7.0. Km and Vmax values of NirB were calculated as 9833 μM and 416.67 μmol NO2- reduced min−1 mg−1. Enzyme activity decreased by 55% and 50% in the presence of 100 mM nitrate and formate, respectively. The presence of 25 mM Cd2+ protected the enzyme at room temperature and the enzyme showed 10% higher activity in the presence of cadmium.