[Changes of ferroptosis related pathways in hippocampus of mice exposed to high-altitude hypoxia].

The present study aimed to investigate the occurrence of ferroptosis in mouse hippocampal tissue and changes in related pathways after exposure to high-altitude hypoxia. A low-pressure hypoxia model was established using a high-altitude environment at 4 010 m. HE staining was used to observe morphological changes in mouse hippocampal tissue, immunohistochemical staining was used to observe lipid peroxidation levels in hippocampal tissue, and corresponding kits were used to measure malondialdehyde (MDA), reduced glutathione (GSH), and Fe2+ levels in hippocampal tissue. Western blot was used to detect glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), ferritin heavy chain 1 (FTH1), ferroportin 1 (FPN1), transferrin receptor 1 (TfR1), ferroptosis suppressor protein 1 (FSP1), and acyl-CoA synthase long chain family member 4 (ACSL4). The results showed that, compared with the plain control group, the mice exposed to high-altitude hypoxia for 1, 3, 7, and 14 d exhibited significant pathological damage, disordered arrangement, and obvious nuclear condensation in the dentate gyrus of the hippocampus. Compared with the plain control group, high-altitude hypoxia exposure increased 4-hydroxynonenal (4-HNE) content in the dentate gyrus and hippocampal MDA content, whereas significantly decreased hippocampal GSH content. Compared with the plain control group, the Fe2+ content in the hippocampus of mice exposed to high-altitude hypoxia for 14 d significantly increased. Compared with the plain control group, the protein expression levels of GPX4, FTH1, FPN1, TfR1, and FSP1 in the hippocampus of mice exposed to high-altitude hypoxia were significantly down-regulated (SLC7A11 was significantly down-regulated only in the 7-d high-altitude hypoxia exposure group), while the protein expression level of ACSL4 was only significantly up-regulated in the 14-d high-altitude hypoxia exposure group. These results suggest that exposure to high-altitude hypoxia for 14 d can reduce GSH synthesis in mouse hippocampus, down-regulate GPX4 expression, lead to GSH metabolism disorders, inhibit iron storage and efflux, promote lipid peroxidation reaction, and inhibit CoQ10H2's anti-lipid peroxidation effect, ultimately leading to ferroptosis.

[Research progress of ferroptosis in hypoxia-associated brain injury].

Cerebral hypoxia often brings irreversible damage to the central nervous system, which seriously endangers human health. It is of great significance to further explore the mechanism of hypoxia-associated brain injury. As a programmed cell death, ferroptosis mainly manifests as cell death caused by excessive accumulation of iron-dependent lipid peroxides. It is associated with abnormal glutathione metabolism, lipid peroxidation and iron metabolism, and is involved in the occurrence and development of various diseases. Studies have found that ferroptosis plays an important role in hypoxia-associated brain injury. This review summarizes the mechanism of ferroptosis, and describes its research progress in cerebral ischemia reperfusion injury, neonatal hypoxic-ischemic brain damage, obstructive sleep apnea-induced brain injury and high-altitude hypoxic brain injury.

Facile in Situ Transformation of NiOOH into MOF-74(Ni)/NiO OH Heterogeneous Composite for Enchancing Electrocatalytic Methanol Oxidation.

A new MOF-74(Ni)/NiOOH heterogeneous composite was synthesized via NiOOH microsphere precursor. The electrocatalytic methanol oxidation reactions' (MOR) performance was assessed. The as-prepared MOF-74(Ni)/NiOOH exhibited excellent activity with high peak current density (27.62 mA·cm-2) and high mass activity (243.8 mA·mg-1). The enhanced activity could be a result of the synergistic effect of the MOF-74(Ni)/NiOOH heterocomposite providing more exposed active sites, a beneficial diffusion path between the catalyst surface and electrolyte, and improved conductivity, favorable for improving MOR performance.

New prenylflavonol glycosides with xanthine oxidase inhibitory activity from the leaves of Cyclocarya paliurus.

Eight new prenylflavonol glycosides (1-8), along with five known analogues (9-13) were isolated from the n-butanol extract of the dried leaves of Cyclocarya paliurus (family Juglandaceae) for the first time. The structures of these compounds were characterized by comprehensive analysis of 1D, 2D NMR, HRESIMS, UV data and acid hydrolysis. In bioassay, all these thirteen prenylflavonol glycosides exhibited inhibitory effects on xanthine oxidase (XOD) activity. Especially compounds 2 and 7, showed outstanding IC50 values of 31.81 ± 2.20 and 29.71 ± 3.69 µM, respectively.

Ar plasma assists in enhanced oxygen evolution kinetics of MOG-derived multicomponent transition metal sulfides.

Transition metal sulfides are low-cost oxygen evolution reaction (OER) electrocatalysts that can potentially substitute noble metal catalysts. However, the adsorption process of their OER is impeded by their intrinsic poor catalytic activity. Constructing heterojunction and vacancy defects in transition metal sulfides is an efficient method to promote the process of oxygen evolution. Herein, a facile approach based on in situ sulfurization of metal-organic gels (MOGs) and a short-time plasma treatment was developed to fabricate vacancy-modified polymetallic sulfides heterojunction. The synergistic effect of the multi-component heterojunction and sulfur vacancy contributed greatly to improving the electron migration efficiency and OER ability of the electrocatalyst. As a result, the optimum oxygen evolution activity was achieved with appropriate surface vacancy concentrations by regulating the plasma radio frequency powers. The plasma-treated catalyst under 400 W showed the best OER performance (lower overpotential of 235 mV in 1 M KOH solution with the Tafel slope of 31 mV dec-1) and good durability over 11 h of chronopotentiometry testing. This work sheds new light on constructing multimetal-based heterojunction electrocatalysts with rich vacancy defects for oxygen evolution reactions.

Four new prenylflavonol glycosides from the leaves of Cyclocarya paliurus.

Four new prenylflavonol glycosides (1-4) along with two known analogues (5-6) were isolated from the leaves of Cyclocarya paliurus for the first time. The structures of these compounds were characterized by comprehensive analysis of 1 D, 2 D NMR, HRESIMS, UV data and enzymatic hydrolysis. In bioassays, compounds 1-4 were evaluated for inhibitory effects on xanthine oxidase (XOD) and effects on the inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS) induced RAW264.7 cells. Moreover, compounds 1 and 2 showed outstanding XOD inhibitions with IC50 values of 18.16 ± 3.91 and 37.65 ± 5.67 µM, and exhibited inhibitions against LPS-induced NO production with IC50 values of 80.50 ± 3.09 and 82.28 ± 2.87 µM.

Cytotoxic triterpenoid glycosides from leaves of Cyclocarya paliurus.

Three previously undescribed dammarane triterpenoid glycosides (1-3) along with five known analogues (4-8) were isolated from the leaves of Cyclocarya paliurus. Their structures and configurations were determined on the basis of comprehensive spectroscopic analyses, chemical hydrolysis and DFT GIAO 13C NMR calculation. All the isolates were evaluated cytotoxic activities against seven human cancer cell lines (MCF-7, PC-3, Du145, NCI-H1975, PC-9, SKVO3 and HepG2). Moreover, compound 4 showed a wide spectrum of cytotoxicity against human cancer cells with IC50 values ranging from 11.31 to 29.51 µM.