Inflammatory bowel diseases (IBD) are chronic intestinal disorders that result from an inappropriate inflammatory response to the microbiota in genetically susceptible individuals, often triggered by environmental stressors. Part of this response is the persistent inflammation and tissue injury associated with deficiency or excess of reactive oxygen species (ROS). The NADPH oxidase NOX1 is highly expressed in the intestinal epithelium, and inactivating NOX1 missense mutations are considered a risk factor for developing very early onset IBD. Albeit NOX1 has been linked to wound healing and host defence, many questions remain about its role in intestinal homeostasis and acute inflammatory conditions. Here, we used in vivo imaging in combination with inhibitor studies and germ-free conditions to conclusively identify NOX1 as essential superoxide generator for microbiota-dependent peroxynitrite production in homeostasis and during early endotoxemia. NOX1 loss-of-function variants cannot support peroxynitrite production, suggesting that the gut barrier is persistently weakened in these patients. One of the loss-of-function NOX1 variants, NOX1 p. Asn122His, features replacement of an asparagine residue located in a highly conserved HxxxHxxN motif. Modelling the NOX1-p22 complex revealed near the distal heme an internal pocket restricted by His119 and Asn122 that is part of the oxygen reduction site. Functional studies in several human NADPH oxidases show that substitution of asparagine with amino acids with larger side chains is not tolerated, while smaller side chains can support catalytic activity. Thus, we identified a previously unrecognized structural feature required for the electron transfer mechanism in human NADPH oxidases.
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http://dx.doi.org/10.1016/j.redox.2023.102905 | DOI Listing |
Chem Asian J
January 2025
Fudan University, Department of Environmental Science and Engineering, Shanghai Handan Road 220, 200433, Shanghai, CHINA.
Novel Ce1-xMnxVO4 catalysts prepared via modified hydrothermal synthesis were used in selective catalytic reduction of NO using NH3 (NH3-SCR). The Ce1-xMnxVO4 catalysts displayed optimum NO removal efficiency at 250 oC. Physicochemical properties including crystal type, morphology, particle size, elemental composition, BET surface area, chemical bond, and valence state were studied by XRD, TEM, EDS, N2 adsorption-desorption, Raman spectroscopy, and XPS.
View Article and Find Full Text PDFEMBO Rep
January 2025
Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.
Cyclic diguanosine monophosphate (c-di-GMP) is a ubiquitous bacterial secondary messenger with diverse functions. A previous Escherichia coli proteome microarray identified that c-di-GMP binds to the 23S rRNA methyltransferases RlmI and RlmE. Here we show that c-di-GMP inhibits RlmI activity in rRNA methylation assays, and that it modulates ribosome assembly in the presence of kanamycin.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Chemistry, Faculty of Science, Arak University, Arak, 38481-77584, Iran.
In this study, a novel hybrid nanostructure consisting of acid-decorated chitosan and magnetic AlFeO nanoparticles was fabricated. The acid-decorated chitosan provided a stable and biocompatible matrix for the magnetic AlFeO nanoparticles. Various techniques including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction patterns (XRD), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), specific surface area (BET), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were used to characterize and confirm the successful synthesis of the hybrid nanostructure.
View Article and Find Full Text PDFNat Commun
January 2025
National Key Laboratory of Uranium Resource Exploration-Mining and Nuclear Remote Sensing, East China University of Technology, Nanchang, 330013, China.
Piezoelectric catalysis possesses the potential to convert ocean wave energy into and holds broad prospects for extracting uranium from seawater. Herein, the Z-type ZnO@COF heterostructure composite with excellent piezoelectric properties was synthesized through in situ growth of covalent organic frameworks (COFs) on the surface of ZnO and used for efficient uranium extraction. The designed COFs shell enables ZnO with stability, abundant active sites and high-speed electron transport channels.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, The University of Hong Kong, Hong Kong 999077, P. R. China.
Electron donor-acceptor complexes are commonly employed to facilitate photoinduced radical-mediated organic reactions. However, achieving these photochemical processes with catalytic amounts of donors or acceptors can be challenging, especially when aiming to reduce catalyst loadings. Herein, we have unveiled a framework-based heterogenization approach that significantly enhances the photoredox activity of perylene diimide species in radical addition reactions with alkyl silicates by promoting faster and more efficient electron donor-acceptor complex formation.
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