The
severe harm of depression to human life has attracted great
attention to neurologists, but its pathogenesis is extremely complicated
and has not yet been fully elaborated. Here, we provided a new strategy
for revealing the specific pathways of abnormal brain glucose catabolism
in depression, based on the supply of energy substrates and the evaluation
of the mitochondrial structure and function. By using stable isotope-resolved
metabolomics, we discovered that the tricarboxylic acid cycle (TCA
cycle) is blocked and gluconeogenesis is abnormally activated in chronic
unpredictable mild stress (CUMS) rats. In addition, our results showed
an interesting phenomenon that the brain attempted to activate all
possible metabolic enzymes in energy-producing pathways, but CUMS
rats still exhibited a low TCA cycle activity due to impaired mitochondria.
Depression caused the mitochondrial structure and function to be impaired
and then led to abnormal brain glucose catabolism. The combination
of the stable isotope-resolved metabolomics and mitochondrial structure
and function analysis can accurately clarify the mechanism of depression.
The mitochondrial pyruvate carrier and acetyl-CoA may be the key targets
for depression treatment. The strategy provides a unique insight for
exploring the mechanism of depression, the discovery of new targets,
and the development of ideal novel antidepressants. Data are available
via ProteomeXchange with identifier PXD025548.
Depression is one of the most prevalent and serious mental disorders with a worldwide significant health burden. Metabolic abnormalities and disorders in patients with depression have attracted great research attention. Thirty-six metabolic biomarkers of clinical plasma metabolomics were detected by platform technologies, including gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) and proton nuclear magnetic resonance (1 H-NMR), combined with multivariate data analysis techniques in previous work. The principal objective of this study was to provide valuable information for the pathogenesis of depression by comprehensive analysis of 36 metabolic biomarkers in the plasma of depressed patients. The relationship between biomarkers and enzymes were collected from the HMDB database. Then the metabolic biomarkers-enzymes interactions (MEI) network was performed and analyzed to identify hub metabolic biomarkers and enzymes. In addition, the docking score-weighted multiple pharmacology index (DSWMP) was used to assess the important pathways of hub metabolic biomarkers involved. Finally, validated these pathways by published literature. The results show that stearic acid, phytosphingosine, glycine, glutamine and phospholipids were important metabolic biomarkers. Hydrolase, transferase and acyltransferase involve the largest number of metabolic biomarkers. Nine metabolite targets (TP53, IL1B, TNF, PTEN, HLA-DRB1, MTOR, HRAS, INS and PIK3CA) of potential drug proteins for treating depression are widely involved in the nervous system, immune system and endocrine system. Seven important pathways, such as PI3K-Akt signaling pathway and mTOR signaling pathway, are closely related to the pathology mechanisms of depression. The application of important biomarkers and pathways in clinical practice may help to improve the diagnosis of depression and the evaluation of antidepressant effect, which provides important clues for the study of metabolic characteristics of depression.
Chopped carbon fibers with different dispersion types (colony type and uniform type) and area densities were inserted at sandwich beams, consisting of a PVC foam core covered with two glass fiber/epoxy composite face sheets. The effects of this reinforcement on the interfacial bonding between PVC foam core and glass fiber face sheets were evaluated. Their mechanical properties were measured by three-point-bending and Charpy impact tests. Their structures after mechanical failure were observed by scanning electron microscopy. Compared with the beam without interfacial reinforcement, the bending strength, energy absorption, and impact strength after interfacial reinforcement using 20 g/m 2 uniform chopped fibers increased by up to 109%, 184%, and 47%, respectively, surpassing those of other chopped fiber mats. The weight percentage of carbon fibers/sandwich structure was less than 1%, so the chopped carbon fiber interleave had both cost effectiveness and outstanding structural performance. The improvement of interlayer toughness can mainly be attributed to the fiber bridging structure and the interlayer strength. POLYM. COMPOS., 00:000-000, FIG. 7. Impact toughness of sandwich samples with different distribution chopped fiber sandwich. (The error bars mark the standard deviation, and minimum five specimens were tested for each case.) [Color figure can be viewed at wileyonlinelibrary.com.]
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