ABSTRACT
We present an alternative scheme to achieve nonreciprocal unconventional magnon blockade (NUMB) in a hybrid system formed by two microwave cavities and one yttrium iron garnet (YIG) sphere, where the pump and signal cavities interact nonlinearly with each other and the signal cavity is coupled to the YIG sphere. It is found that the nonlinear coupling occurs between the pump cavity and magnon modes due to the dispersive interactions among three bosonic modes. Meanwhile, the Kerr nonlinearity is present in the pump cavity. Based on these nonlinear effects, a nonreciprocal magnon blockade could be achieved with the help of the weak parametric driving of the pump cavity. The present work provides an alternative method to prepare single magnon resource, which may be helpful for quantum information processing.
ABSTRACT
BACKGROUND: Autophagic flux is coordinated by a network of master regulatory genes, which centered on transcription factor EB (TFEB). The disorders of autophagic flux are closely associated with Alzheimer's disease (AD), and thus restoring autophagic flux to degrade pathogenic proteins has become a hot therapeutic strategy. Hederagenin (HD), a triterpene compound, isolated from a variety food such as Matoa (Pometia pinnata) Fruit, Medicago sativa, Medicago polymorpha L. Previous studies have shown that HD has the neuroprotective effect. However, the effect of HD on AD and underlying mechanisms are unclear. PURPOSE: To determine the effect of HD on AD and whether it promotes autophagy to reduce AD symptoms. STUDY DESIGN: BV2 cells, C. elegans and APP/PS1 transgenic mice were used to explore the alleviative effect of HD on AD and the molecular mechanism in vivo and in vitro. METHODS: The APP/PS1 transgenic mice at 10 months were randomized into 5 groups (n = 10 in each group) and orally administrated with either vehicle (0.5% CMCNa), WY14643 (10 mg/kg/d), low-dose of HD (25 mg/kg/d), high-dose of HD (50 mg/kg/d) or MK-886 (10 mg/kg/d) + HD (50 mg/kg/d) for consecutive 2 months. The behavioral experiments including morris water maze test, object recognition test and Y maze test were performed. The effects of HD on Aß deposition and alleviates Aß pathology in transgenic C. elegans were operated using paralysis assay and fluorescence staining assay. The roles of HD in promoting PPARα/TFEB-dependent autophagy were investigated using the BV2 cells via western blot analysis, real-time quantitative PCR (RT-qPCR), molecular docking, molecular dynamic (MD) simulation, electron microscope assay and immunofluorescence. RESULTS: In this study, we found that HD upregulated mRNA and protein level of TFEB and increased the distribution of TFEB in the nucleus, and the expressions of its target genes. HD also promoted the expressions of LC3BII/LC3BI, LAMP2, etc., and promoted autophagy and the degradation of Aß. HD reduced Aß deposition in the head area of C. elegans and Aß-induced paralysis. HD improved cognitive impairment and pathological changes in APP/PS1 mice by promoting autophagy and activating TFEB. And our results also showed that HD could strongly target PPARα. More importantly, these effects were reversed by treatment of MK-886, a selective PPARα antagonist. CONCLUSION: Our present findings demonstrated that HD attenuated the pathology of AD through inducing autophagy and the underlying mechanism associated with PPARα/TFEB pathway.
Subject(s)
Alzheimer Disease , Animals , Mice , Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Autophagy , Caenorhabditis elegans/metabolism , Disease Models, Animal , Mice, Transgenic , Molecular Docking Simulation , PPAR alphaABSTRACT
BACKGROUND/AIMS: Endothelial dysfunction is a major factor in the progression of chronic kidney disease, which correlates with oxidative stress and NO deficiency. Huangqi decoction (HQD) is a potential anti-oxidant ingredient in renoprotection. However, the underlying mechanisms remained identified. Therefore, we investigated whether HQD exhibit improvement in endothelial dysfunction in the 5/6 nephrectomy (Nx) rat model. METHODS: Male Wistar rats (180 - 250 g) were divided into sham, Nx and Nx + HQD (0.05, 0.15 and 0.45 g/kg) group, respectively. Renal function and histology were examined with ELISA and Immunohistochemical analysis. Endothelium-dependent relaxation of rat aortas was investigated by isometric tension recordings. Oxidative stress and NO bioavailability were detected by ELISA, DHE-staining, DAF-2 staining and western blotting. RESULTS: Compared with Nx rats, HQD treatment reversed the functional and structural changes of kidney significantly. Besides, endothelium-dependent relaxation of rat aortas was also improved by HQD treatment. NADPH oxidase and ROS generation were inhibited while NO bioavailability was enhanced. CONCLUSION: HQD can act as a potent prescription for the treatment of endothelium related vascular complications.
Subject(s)
Drugs, Chinese Herbal/pharmacology , Endothelium, Vascular/drug effects , Endothelium, Vascular/physiopathology , Nephrectomy , Animals , Aorta/drug effects , Aorta/physiopathology , Body Weight/drug effects , Kidney/pathology , Kidney/physiopathology , Kidney/surgery , Male , NADPH Oxidases/metabolism , Nitric Oxide/metabolism , Rats, Wistar , Reactive Oxygen Species/metabolismABSTRACT
Vascular endothelial dysfunction can be induced by homocysteine (Hcy) through promoted oxidative stress. Huang Qi decoction (HQD) is a traditional Chinese medical formula and its components possess antioxidant effect. The study herein was therefore designed to investigate the effects of HQD at different dosage on endothelial dysfunction induced by Hcy. Tempol and apocynin were used to investigate whether antioxidant mechanisms were involved. Endothelium-dependent relaxation of rat aortas was investigated by isometric tension recordings. Reactive oxygen species (ROS) in human umbilical vein endothelial cells (HUVECs) was determined by DHE staining. The assessment related to oxidative stress and NO bioavailability was performed by assay kits and western blot. In isometric tension experiment, HQD at the dose of 30 or 100 µg/mL, tempol, or apocynin prevented impaired endothelium-dependent relaxation in isolated aortas elicited by Hcy. In cellular experiments, substantial enhancement in NADPH oxidase and ROS generation and reduction in NO bioavailability triggered by Hcy were reversed by pretreatment of HQD at the dose of 100 µg/mL, tempol, or apocynin. The results proved that HQD at an appropriate dosage presented favorable effects on endothelial dysfunction initiated by Hcy through antioxidant mechanisms. HQD can act as a potent prescription for the treatment of endothelium related vascular complications.