Uric acid regulates NLRP3/IL-1ß signaling pathway and further induces vascular endothelial cells injury in early CKD through ROS activation and K+ efflux.

BACKGROUND: Chronic kidney disease (CKD) has been considered as a major health problem in the world. Increasing uric acid (UA) could induce vascular endothelial injury, which is closely related to microinflammation, oxidative stress, and disorders of lipids metabolism. However, the specific mechanism that UA induces vascular endothelial cells injury in early CKD remains unknown. METHODS: Human umbilical vein endothelial cells (HUVECs) were cultured and subjected to different concentrations of UA for different periods. Early CKD rat model with elevated serum UA was established. Western blotting and quantitative real-time PCR (qPCR) were applied for measuring protein and mRNA expression of different cytokines. The animals were sacrificed and blood samples were collected for measurement of creatinine, UA, IL-1ß, TNF-α, and ICAM-1. Renal tissues were pathologically examined by periodic acid-Schiff (PAS) or hematoxylin-eosin (HE) staining. RESULTS: The expression of IL-1ß, ICAM-1, NLRP3 complexes, and activation of NLRP3 inflammasome could be induced by UA, but the changes induced by UA were partially reversed by siRNA NLRP3 or caspase 1 inhibitor. Furthermore, we identified that UA regulated the activation of NLRP3 inflammasome by activating ROS and K+ efflux. In vivo results showed that UA caused the vascular endothelial injury by activating NLRP3/IL-1ß pathway. While allopurinol could reduce UA level and may have protective effects on cardiovascular system. CONCLUSIONS: UA could regulate NLRP3/IL-1ß signaling pathway through ROS activation and K+ efflux and further induce vascular endothelial cells injury in early stages of CKD.

Switched photoelectrochemistry of carbon dots for split-type immunoassay.

A novel and general strategy of split-type immunoassay is developed based on redox chemical reaction modulated photoelectrochemistry of carbon dots (CDs). Specifically, the photocurrent of the CDs sensitized titanium dioxide nanoparticles (TiO2 NPs) modified fluorine doped indium tin oxide (FTO) (that is the FTO/TiO2/CDs) electrode was inhibited obviously by KMnO4 due to the oxidation of surface hydroxyl groups of CDs to electron accepting carbonyls. While the inhibited photocurrent of the KMnO4 treated FTO/TiO2/CDs electrode can be restored by ascorbic acid (AA) because of the regeneration of electron donating hydroxyls to promote electron-hole separation. Take carcinoembryonic antigen (CEA) as a model analyte and alkaline phosphate (ALP) as a catalytic label tracer to hydrolyze ascorbic acid 2-phosphate (AAP) for producing AA, which greatly stimulated the photocurrent of the transducer of KMnO4 treated FTO/TiO2/CDs photoelectrode for signal output. This redox chemical reaction modulated PEC strategy enabled the separation of the immunoreaction from the photoelectrode (that is, a split-type PEC detection), eliminating potential damage of biomolecules during the PEC detection processes and leading to enhanced throughput detection as compared to conventional PEC configurations. A low detection limit of 7.0 fg/mL was achieved for CEA. This convenient, split-type PEC immunoassay with high throughput may be easily extended to other bioaffinity assays for versatile targets.