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Ca2+ overload-induced mitochondrial dysfunction is considered a contributing factor alcohol-associated liver disease pathogenesis. Here the authors report that PDK4 promotes Ca2 + -channelling complex formation at the endoplasmic reticulum-mitochondria contact sites, which contributes to the pathogenesis of alcohol-associated liver disease in studies with male mouse and hepatocyte models.

Summary: Recent developments in genome sequencing have expanded the knowledge of genetic factors associated with late-onset Alzheimer’s disease (AD). Among them, genetic variant ε4 of the APOE gene (APOE4) confers the greatest disease risk. Dysregulated glucose metabolism is an early pathological feature of AD. Using isogenic ApoE3 and ApoE4 astrocytes derived from human induced pluripotent stem cells, we find that ApoE4 increases glycolytic activity but impairs mitochondrial respiration in astrocytes. Ultrastructural and autophagy flux analyses show that ApoE4-induced cholesterol accumulation impairs lysosome-dependent removal of damaged mitochondria. Acute treatment with cholesterol-depleting agents restores autophagic activity, mitochondrial dynamics, and associated proteomes, and extended treatment rescues mitochondrial respiration in ApoE4 astrocytes. Taken together, our study provides a direct link between ApoE4-induced lysosomal cholesterol accumulation and abnormal oxidative phosphorylation.

Abstract Background Muscle atrophy, leading to muscular dysfunction and weakness, is an adverse outcome of sustained period of glucocorticoids usage. However, the molecular mechanism underlying this detrimental condition is currently unclear. Pyruvate dehydrogenase kinase 4 (PDK4), a central regulator of cellular energy metabolism, is highly expressed in skeletal muscle and has been implicated in the pathogenesis of several diseases. The current study was designed to investigated and delineate the role of PDK4 in the context of muscle atrophy, which could be identified as a potential therapeutic avenue to protect against dexamethasone‐induced muscle wasting. Methods The dexamethasone‐induced muscle atrophy in C2C12 myotubes was evaluated at the molecular level by expression of key genes and proteins involved in myogenesis, using immunoblotting and qPCR analyses. Muscle dysfunction was studied in vivo in wild‐type and PDK4 knockout mice treated with dexamethasone (25 mg/kg body weight, i.p., 10 days). Body weight, grip strength, muscle weight and muscle histology were assessed. The expression of myogenesis markers were analysed using qPCR, immunoblotting and immunoprecipitation. The study was extended to in vitro human skeletal muscle atrophy analysis. Results Knockdown of PDK4 was found to prevent glucocorticoid‐induced muscle atrophy and dysfunction in C2C12 myotubes, which was indicated by induction of myogenin (0.3271 ± 0.102 vs 2.163 ± 0.192, ****P

Age-related macular degeneration (AMD), especially neovascular AMD with choroidal neovascularization (CNV), is the leading cause of blindness in the elderly. Although matrix metalloproteinases (MMPs) are involved in pathological ocular angiogenesis, including CNV, the cellular origin of MMPs in AMD remains unknown. The present study investigated the role of microglial MMPs in CNV. MMP activities were analyzed by gelatin zymography in aqueous humor samples from patients with CNV and laser-induced CNV mice. Active MMP-9 was increased in the aqueous humor samples from neovascular AMD patients compared with control subjects. In the retinal pigment epithelium (RPE)/choroid from CNV mice, active MMP-9 increased, beginning 1 h post-CNV induction, and remained upregulated until Day 7. In RPE/choroid from CNV mice, active MMP-9 was suppressed by minocycline, a known microglial inhibitor, at 6 h and 1-day post-CNV induction. Flow cytometry revealed that the proportion of activated microglia increased very early, beginning at 1 h post-CNV induction, and was maintained until Day 7. Similarly, immunohistochemistry revealed increased microglial activation and MMP-9 expression on CNV lesions at 6 h and 1-day post-CNV induction. SB-3CT, an MMP inhibitor, decreased vascular leakage and lesion size in laser-induced CNV mice. These findings indicated nearly immediate recruitment of activated microglia and very early MMP-9 activation in the RPE/choroid. The present study newly identified a potential role for early microglial MMP-9 expression in CNV, and furthermore that modulating microglial MMP expression is a novel putative therapeutic for CNV.

Metabolic reprogramming during macrophage polarization supports the effector functions of these cells in health and disease. Here, we demonstrate that pyruvate dehydrogenase kinase (PDK), which inhibits the pyruvate dehydrogenase-mediated conversion of cytosolic pyruvate to mitochondrial acetyl-CoA, functions as a metabolic checkpoint in M1 macrophages. Polarization was not prevented by PDK2 or PDK4 deletion but was fully prevented by the combined deletion of PDK2 and PDK4; this lack of polarization was correlated with improved mitochondrial respiration and rewiring of metabolic breaks that are characterized by increased glycolytic intermediates and reduced metabolites in the TCA cycle. Genetic deletion or pharmacological inhibition of PDK2/4 prevents polarization of macrophages to the M1 phenotype in response to inflammatory stimuli (lipopolysaccharide plus IFN-γ). Transplantation of PDK2/4-deficient bone marrow into irradiated wild-type mice to produce mice with PDK2/4-deficient myeloid cells prevented M1 polarization, reduced obesity-associated insulin resistance, and ameliorated adipose tissue inflammation. A novel, pharmacological PDK inhibitor, KPLH1130, improved high-fat diet-induced insulin resistance; this was correlated with a reduction in the levels of pro-inflammatory markers and improved mitochondrial function. These studies identify PDK2/4 as a metabolic checkpoint for M1 phenotype polarization of macrophages, which could potentially be exploited as a novel therapeutic target for obesity-associated metabolic disorders and other inflammatory conditions.

More and more devices are equipped with global positioning system (GPS). However, those handheld devices with consumer-grade GPS receivers usually have low accuracy in positioning. A position correction algorithm is therefore useful in this case. In this paper, we proposed an evolutionary computation based technique to generate a correction function by two GPS receivers and a known reference location. Locating one GPS receiver on the known location and combining its longitude and latitude information and exact poisoning information, the proposed technique is capable of evolving a correction function by such. The proposed technique can be implemented and executed on handheld devices without hardware reconfiguration. Experiments are conducted to demonstrate performance of the proposed technique. Positioning error could be significantly reduced from the order of 10 m to the order of 1 m.

Science teachers use a large number of visual representations and models in science classes to guide students to understand complex phenomena and to learn to conduct scientific inquiry. Fluent formation and use of visual representation involves metavisualization, which is a process related to metacognition and visualization. However, what kinds of knowledge and skills are involved and interact during successful metavisualization need further research. Moreover, teachers' metavisualization should be a focus of research since teachers play a mediating role in guiding students to become proficient performers of visualization in science. Therefore, in this study, we investigated how an experienced science teacher performed metavisualization via qualitative data collection techniques including think-aloud tasks and a follow-up retrospective interview. We identified the relevant knowledge and skills that were involved in the teacher's metavisualization. Moreover, by focusing on the interaction among the knowledge and skills, we observed three aspects of the teacher's performance that were salient to her metavisualization, including the use of metavisual strategies, judgement criteria, and the encountered critical points. Drawing upon previous perspectives and this study's findings, we propose a model of metavisualization by extending an existing model for further research. The findings also provide insight into teacher professional development programs.

Insomnia is a common sleep disorder with significant societal and economic impacts. Current pharmacotherapies for insomnia are often accompanied by side effects, necessitating the development of new therapeutic drugs. In this study, the hypnotic effects and mechanisms of Sedum kamtschaticum 30% ethanol extract (ESK) and one of its active compounds, myricitrin, were investigated using pentobarbital-induced sleep experiments, immunohistochemistry (IHC), receptor binding assays, and enzyme-linked immunosorbent assay (ELISA). The pentobarbital-induced sleep experiments revealed that ESK and myricitrin reduced sleep latency and prolonged total sleep time in a dose-dependent manner. Based on c-Fos immunostaining, ESK, and myricitrin enhanced the GABAergic neural activity in sleep-promoting ventrolateral preoptic nucleus (VLPO) GABAergic. By measuring the level of GABA released from VLPO GABAergic neurons, ESK and myricitrin were found to increase GABA release in the hypothalamus. These effects were significantly inhibited by SCH. Moreover, ESK exhibited a concentration-dependent binding affinity for the adenosine A2A receptors (A2AR). In conclusion, ESK and myricitrin have hypnotic effects, and their underlying mechanisms may be related to the activation of A2AR. [ABSTRACT FROM AUTHOR]