A novel anti-inflammatory mechanism of high density lipoprotein through up-regulating annexin A1 in vascular endothelial cells.

High density lipoprotein (HDL) as well as annexin A1 have been reported to be associated with cardiovascular protection. However, the correlation between HDL and annexin A1 was still unknown. In this study, HDL increased endothelial annexin A1 and prevented the decrease of annexin A1 in TNF-α-activated endothelial cells in vitro and in vivo, and above effects were attenuated after knockdown of annexin A1. Annexin A1 modulation affected HDL-mediated inhibition of monocyte adhesion to TNF-α-activated endothelium (45.2±13.7% decrease for annexin A1 RNA interference; 78.7±16.3% decrease for anti-Annexin A1 antibody blocking; 11.2±6.9% increase for Ad-ANXA1 transfection). Additionally, HDL up-regulated annexin A1 through scavenger receptor class B type I, involving ERK, p38MAPK, Akt and PKC signaling pathways, and respective inhibitors of these pathways attenuated HDL-induced annexin A1 expression as well as impaired HDL-mediated inhibition of monocyte-endothelial cell adhesion. Apolipoprotein AI also increased annexin A1 and activated similar signaling pathways. Endothelial annexin A1 from apolipoprotein AI knockout mice was decreased in comparison to that from wild type mice. Finally, HDL-induced annexin A1 inhibited cell surface VCAM-1, ICAM-1 and E-selectin, and secretion of MCP-1, IL-8, VCAM-1 and E-selectin, thereby inhibiting monocyte adhesion.

P4HA2-induced prolyl hydroxylation of YAP1 restricts vascular smooth muscle cell proliferation and neointima formation.

Vascular smooth muscle cell (VSMC) proliferation and neointima formation play significant roles in atherosclerosis development and restenosis following percutaneous coronary intervention. Our team previously discovered that TEA domain transcription factor 1 (TEAD1) promotes vascular smooth muscle differentiation, which is necessary for vascular development. Conversely, aberrant YAP1 activation upregulates the platelet-derived growth factor receptor beta to encourage VSMC proliferation and neointima formation. In this study, we aimed to investigate the molecular mechanisms of YAP1/TEAD signaling during neointima formation. Our research focused on the prolyl 4-hydroxylase alpha 2 (P4HA2) and its downstream target, Yes-associated protein 1 (YAP1), in regulating VSMC differentiation and neointima formation. Our results indicated that P4HA2 reduction leads to VSMC dedifferentiation and promotes neointima formation after injury. Furthermore, we found that P4HA2-induced prolyl hydroxylation of YAP1 restricts its transcriptional activity, which is essential to maintaining VSMC differentiation. These findings suggest that targeting P4HA2-mediated prolyl hydroxylation of YAP1 may be a promising therapeutic approach to prevent injury-induced neointima formation in cardiovascular disease.

Fibroblast-specific knockout of METTL1 attenuates myocardial infarction-induced cardiac fibrosis.

Cardiac fibrosis, a common pathology in inherited and acquired heart diseases, necessitates the identification of diagnostic and therapeutic targets. Methyltransferase Like 1 (METTL1), an enzyme responsible for RNA modification by methylating guanosine to form m7G, is an emerging area of research in understanding cellular processes and disease pathogenesis. Dysregulation of m7G modification has been implicated in various diseases. However, the role of METTL1 in cardiac fibrosis remains unclear. This study aimed to investigate the role of METTL1 in myocardial infarction-induced heart failure and cardiac fibrosis. Our findings demonstrate that elevated METTL1-mediated RNA m7G methylation is observed in cardiac fibrosis tissues and TGF-ß1-induced cardiac fibroblast proliferation and myofibroblast transformation. Furthermore, fibroblast-specific knockout of METTL1 attenuated myocardial infarction-induced heart failure and cardiac fibrosis. Additionally, METTL1 knockout decreased m7G methylated fibrotic genes and impaired their translation efficiency. These results suggest a novel pro-fibrosis role of METTL1-mediated RNA m7G methylation, highlighting its potential as a therapeutic target in cardiac fibrosis.

Visible-light-induced photo-Fenton process for the facile degradation of metronidazole by Fe/Si codoped TiO2.

This work investigated the feasibility and efficiency of a heterogeneous photo-Fenton catalyst, Fe/Si codoped TiO2, for the degradation of metronidazole (MNZ) under visible light irradiation. The Fe/Si codoped TiO2 was prepared via a facile and simple sol-gel solvothermal process followed by annealing at 480 °C for 4 hours. High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) measurements revealed that the photo-Fenton process did not change the structure, textural and surface morphologies of this catalyst. Elemental mapping results indicated the good dispersion of Fe and Si ions in TiO2. Nitrogen adsorption and desorption measurements indicated that Si doping increased the surface area of the catalysts. The Fe and Si doping narrowed the band gap of TiO2. They also facilitated the transfer of photo-generated electrons from TiO2 to Fe(iii). Under visible light irradiation and the optimum operating conditions, MNZ could be completely degraded in 50 min by this catalyst within a wide pH range. Hydroxyl radicals and holes were verified to be responsible for degrading MNZ. The leaching of iron ions was less than 0.047 ppm even after illuminating the catalyst for 6 hours, indicating the good stability of the Fe/Si codoped TiO2. The as-prepared catalysts with excellent catalytic activity, and remarkable reusability and stability could provide a new insight into the preparation of photocatalysts and have wide applications for antibiotics removal.

Three-dimensional nitrogen-doped graphene foam as metal-free catalyst for the hydrogenation reduction of p-nitrophenol.

Developing metal-free catalysts for various applications has been the focus of high interest over the past decade, especially aiming to replace the expensive noble metal-based catalysts. Herein, a well-defined three-dimensional nitrogen-doped graphene foam (3D-NGF) is synthesized and employed as a metal-free catalyst for the hydrogenation reduction of p-Nitrophenol to p-Aminophenol. The apparent activation energy is calculated, and the reaction mechanism with 3D-NGF as the catalyst for the hydrogenation reduction of p-Nitrophenol is proposed. Importantly, the 3D-NGF demonstrates high catalytic activity and robust stability. The high activity can be ascribed to the synergistic effect between the nitrogen-doping induced change in electronic property and the 3D foam-like structure.

Catalytic wet peroxide oxidation of aniline in wastewater using copper modified SBA-15 as catalyst.

SBA-15 mesoporous molecular sieves modified with copper (Cu-SBA-15) were prepared by pH-adjusting hydrothermal method and characterized by X-ray diffraction, BET, transmission electron microscopy, UV-Vis and (29)Si MAS NMR. The pH of the synthesis gel has a significant effect on the amount and the dispersion of copper on SBA-15. The Cu-SBA-15(4.5) (where 4.5 denotes the pH value of the synthesis gel) modified with highly dispersed copper was used as catalyst for the oxidation of aniline by H2O2. The Cu-SBA-15(4.5) shows a higher catalytic activity compared to CuO on the surface of SBA-15. The influences of reaction conditions, such as initial pH of the aqueous solutions, temperature, as well as the dosages of H2O2 and catalyst were investigated. Under weakly alkaline aqueous solution conditions, the aniline conversion, the H2O2 decomposition and the total organic carbon (TOC) removal could be increased significantly compared to the acid conditions. The percentage of leaching Cu(2+) could be decreased from 45.0% to 3.66% when the initial pH of solution was increased from 5 to 10. The TOC removal could be enhanced with the increases of temperature, H2O2 and catalyst dosage, but the aniline conversion and H2O2 decomposition change slightly with further increasing dosage of catalyst and H2O2. At 343 K and pH 8.0, 100% aniline conversion and 66.9% TOC removal can be achieved under the conditions of 1.0 g/L catalyst and 0.05 mol/L H2O2 after 180 min. Although copper might be slightly leached from catalyst, the homogeneous Cu(2+) contribution to the whole catalytic activity is unimportant, and the highly dispersed copper on SBA-15 plays a dominant role.

Room temperature ferromagnetism and photoluminescence in Cu-doped ZnO nanocrystals.

The Zn(1-x)Cu(x)O (x = 0.0-3.5%) nanocrystals have been synthesized by a simple sol-gel method. X-ray diffraction, optical absorption and photoluminescence measurements were employed to validate consistently the incorporation of Cu ions into the ZnO wurtzite lattice without formation of secondary phases for Zn(1-x)Cu(x)O (x < 2.0%). Meanwhile, it was found that the substituted Cu-doping leads to the reduction of the band gap and the appearance of the structured green emission. Magnetization measurement showed that the low Cu-doping (x < 1.0%) develops the ferromagnetism, but the high Cu-doping destroys sharply the ferromagnetism due to the formation of the antiferromagnetic coupling among the neighboring Cu ions. It is indicated that the rational Cu-doping can tune optical and magnetic properties in ZnO.