Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.3.1 (NADPH oxidase)
 11,281 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The NADPH oxidase (Nox) proteins catalyze the regulated formation of reactive oxygen species (ROS), which play key roles as signaling molecules in several physiological and pathophysiological processes. ROS generation by the Nox1 member of the Nox family is necessary for the formation of extracellular matrix (ECM)-degrading, actin-rich cellular structures known as invadopodia. Selective inhibition of Nox isoforms can provide reversible, mechanistic insights into these cellular processes in contrast to scavenging or inhibition of ROS production. Currently no specific Nox inhibitors have been described. Here, by high-throughput screening, we identify a subset of phenothiazines, 2-acetylphenothiazine (here referred to as ML171) (and its related 2-(trifluoromethyl)-phenothiazine) as nanomolar, cell-active, and specific Nox1 inhibitors that potently block Nox1-dependent ROS generation, with only marginal activity on other cellular ROS-producing enzymes and receptors including the other Nox isoforms. ML171 also blocks the ROS-dependent formation of ECM-degrading invadopodia in colon cancer cells. Such effects can be reversed by overexpression of Nox1 protein, which is suggestive of a selective mechanism of inhibition of Nox1 by this compound. These results elucidate the relevance of Nox1-dependent ROS generation in mechanisms of cancer invasion and define ML171 as a useful Nox1 chemical probe and potential therapeutic agent for inhibition of cancer cell invasion.
ACS Chem Biol 2010 Oct 15
PMID:A novel and specific NADPH oxidase-1 (Nox1) small-molecule inhibitor blocks the formation of functional invadopodia in human colon cancer cells. 2071 45

Many Gram-negative bacteria interact with extracellular metal ions by expressing one or more siderophore types. Among these, the virulence-associated siderophore yersiniabactin (Ybt) is an avid copper chelator, forming stable cupric (Cu(II)-Ybt) complexes that are detectable in infected patients. Here we show that Ybt-expressing E. coli are protected from intracellular killing within copper-replete phagocytic cells. This survival advantage is highly dependent upon the phagocyte respiratory burst, during which superoxide is generated by the NADPH oxidase complex. Chemical fractionation links this phenotype to a previously unappreciated superoxide dismutase (SOD)-like activity of Cu(II)-Ybt. Unlike previously described synthetic copper-salicylate (Cu(II)-SA) SOD mimics, the salicylate-based natural product Cu(II)-Ybt retains catalytic activity at physiologically plausible protein concentrations. These results reveal a new virulence-associated adaptation based upon spontaneous assembly of a non-protein catalyst.
ACS Chem Biol 2014 Feb 21
PMID:Cupric yersiniabactin is a virulence-associated superoxide dismutase mimic. 2428 77

Herein, we report a highly sensitive electrocatalytic sensor-cell construct that can electrochemically communicate with the internal environment of immune cells (e.g., macrophages) via the selective monitoring of a particular reactive oxygen species (ROS), hydrogen peroxide. The sensor, which is based on vertically aligned single-walled carbon nanotubes functionalized with an osmium electrocatalyst, enabled the unprecedented detection of a local intracellular "pulse" of ROS on a short second time scale in response to bacterial endotoxin (lipopolysaccharide-LPS) stimulation. Our studies have shown that this initial pulse of ROS is dependent on NADPH oxidase (NOX) and toll like receptor 4 (TLR4). The results suggest that bacteria can induce a rapid intracellular pulse of ROS in macrophages that initiates the classical innate immune response of these cells to infection.
ACS Appl Mater Interfaces 2015 Oct 28
PMID:Fast, Ultrasensitive Detection of Reactive Oxygen Species Using a Carbon Nanotube Based-Electrocatalytic Intracellular Sensor. 2643 64

Chemical cross-linking is well-established for investigating protein-protein interactions. Traditionally, photo cross-linking is used but is associated with problems of selectivity and UV toxicity in a biological context. We here describe, with live cells and under normal growth conditions, selective cross-linking of a furan-modified peptide ligand to its membrane-presented receptor with zero toxicity, high efficiency, and spatio-specificity. Furan-modified kisspeptin-10 is covalently coupled to its glycosylated membrane receptor, GPR54(KISS1R). This newly expands the applicability of furan-mediated cross-linking not only to protein-protein cross-linking but also to cross-linking in situ. Moreover, in our earlier reports on nucleic acid interstrand cross-linking, furan activation required external triggers of oxidation (via addition of N-bromo succinimide or singlet oxygen). In contrast, we here show, for multiple cell lines, the spontaneous endogenous oxidation of the furan moiety with concurrent selective cross-link formation. We propose that reactive oxygen species produced by NADPH oxidase (NOX) enzymes form the cellular source establishing furan oxidation.
ACS Chem Biol 2017 08 18
PMID:Cross-Linking Furan-Modified Kisspeptin-10 to the KISS Receptor. 2871 70

Clostridioides difficile is the leading cause of nosocomial diarrhea in the United States. The primary virulence factors are two homologous glucosyltransferase toxins, TcdA and TcdB, that inactivate host Rho-family GTPases. The glucosyltransferase activity has been linked to a "cytopathic" disruption of the actin cytoskeleton and contributes to the disruption of tight junctions and the production of pro-inflammatory cytokines. TcdB is also a potent cytotoxin that causes epithelium necrotic damage through an NADPH oxidase (NOX)-dependent mechanism. We conducted a small molecule screen to identify compounds that confer protection against TcdB-induced necrosis. We identified an enrichment of "hit compounds" with a dihydropyridine (DHP) core which led to the discovery of a key early stage calcium signal that serves as a mechanistic link between TcdB-induced NOX activation and reactive oxygen species (ROS) production. Disruption of TcdB-induced calcium signaling (with both DHP and non-DHP molecules) is sufficient to ablate ROS production and prevent subsequent necrosis in cells and in a mouse model of intoxication.
ACS Chem Biol 2020 05 15
PMID:Small Molecule Inhibitor Screen Reveals Calcium Channel Signaling as a Mechanistic Mediator of Clostridium difficile TcdB-Induced Necrosis. 3190 64

Marine macroalgae, seaweeds, are exceptionally prolific producers of halogenated natural products. Biosynthesis of halogenated molecules in seaweeds is inextricably linked to reactive oxygen species (ROS) signaling as hydrogen peroxide serves as a substrate for haloperoxidase enzymes that participate in the construction these halogenated molecules. Here, using red macroalga Asparagopsis taxiformis, a prolific producer of the ozone depleting molecule bromoform, we provide the discovery and biochemical characterization of a ROS-producing NAD(P)H oxidase from seaweeds. This discovery was enabled by our sequencing of Asparagopsis genomes, in which we find the gene encoding the ROS-producing enzyme to be clustered with genes encoding bromoform-producing haloperoxidases. Biochemical reconstitution of haloperoxidase activities establishes that fatty acid biosynthesis can provide viable hydrocarbon substrates for bromoform production. The ROS production haloperoxidase enzymology that we describe here advances seaweed biology and biochemistry by providing the molecular basis for decades worth of physiological observations in ROS and halogenated natural product biosyntheses.
ACS Chem Biol 2020 06 19
PMID:Genetic and Biochemical Reconstitution of Bromoform Biosynthesis in Asparagopsis Lends Insights into Seaweed Reactive Oxygen Species Enzymology. 3245 42

Macrophages play essential roles in innate immunity and their functions can be activated by different signals at pathological sites. Concerning changes in the rigidity of the microenvironment as a disease progresses, the influence of stiffened substrates on macrophage physiology remains elusive. In this study, to evaluate the effect of stiffened substrates on macrophages, we used J774A.1 cells as the macrophage model to investigate its mechanoinflammation responses using engineered polymeric substrates with various physiological rigidities (approximately 0.6 to 100 kPa). Under lipopolysaccharide (LPS) and adenosine triphosphate (ATP) stress, approximately 4-fold higher cytoplasmic reactive oxygen species (ROS) were triggered in cells on the softer substrate, compared with cells on the stiff substrates. The enhanced ROS response was found to be regulated mainly by NADPH oxidase. Moreover, mitochondrial ROS (mtROS), a crucial intracellular ROS source, are produced in response to substrate rigidity. The results showed higher mtROS production when cells were grown on a soft substrate with LPS/ATP stimuli, and the mechano-mtROS alteration was eliminated by Rho kinase inhibitor Y-27632. We suggest that substrate rigidity can coincide with LPS/ATP in regulating the ROS generation of macrophages. As a result of the pivotal role of ROS in regulating inflammation, increased NLRP-3 inflammasome formation and higher NO secretion (an approximately 300% increase) were observed with macrophages grown on soft substrates. Although no substantial genomic distinction was identified in our experiments, based on the phenotypic and functional results, softer substrates prime macrophages toward the proinflammatory (M1)-like phenotype. In summary, this study demonstrated the mechanosensitive inflammatory response of macrophages and the alteration of ROS, as secondary inflammation signals, may contribute to the functional status of macrophages. These findings not only provide an alternative interpretation of the functional transitions of macrophages influenced by substrate rigidity but may also support the manipulation of the inflammatory responses of macrophages via physical microenvironment modifications.
ACS Appl Mater Interfaces 2020 Oct 28
PMID:Reactive Oxygen Species and Inflammatory Responses of Macrophages to Substrates with Physiological Stiffness. 3306 43