Toxic cyanobacteria induce coupled changes in gut microbiota and co-metabolite of freshwater gastropods

Untargeted metabolomics study of mature human milk from women with and without gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a prevalent metabolic disorder during pregnancy that alters the metabolites in human milk. Integrated Gas Chromatography-Mass Spectrometry (GC-MS) and Liquid Chromatography-Mass Spectrometry (LC-MS) were employed for comprehensive identification and comparison of metabolites in mature human milk (MHM) from women with and without GDM. A total of 268 differentially expressed metabolites (DEMs) were identified. Among these, linoleic acid, arachidonic acid, 9R-HODE and L-glutamic acid were significantly elevated and 12,13-DHOME was significantly decreased in MHM of women with GDM. These metabolites are significantly enriched in linoleic acid metabolism, fatty acid biosynthesis, galactose metabolism and ABC transporters pathways. Disorders in these metabolic pathways are associated with insulin resistance and poor glucose metabolism indicating these conditions may persist postpartum.

Chronic microcystin-leucine-arginine exposure induces osteoporosis by breaking the balance of osteoblasts and osteoclasts

Microcystin-leucine-arginine (MC-LR) produced by cyanobacterial harmful algal blooms are hazardous materials. However, the toxicity and mechanisms of continuous exposure to MC-LR on the occurrence of osteoporosis remains poorly documented. In this study, to mimic the chronic influences of MC-LR on the bone tissues in humans, an animal model was constructed in which mice were treated with MC-LR through drinking water at an environmentally relevant level (1-30 μg/L) for 6 months. MC-LR was enriched in the skeletal system, leading to the destruction of bone microstructure, the decrease of bone trabecular number, the reduction of osteoblasts, the enhanced content of lipid droplets, and the activation of osteoclasts, which is the characteristic of osteoporosis. Herein, we revealed ferroptosis is a vital mechanism of osteoblast death in mouse models of MC-LR. MC-LR exposure activates AMPK/ULK1 signaling, further promotes ferritin selective autophagy, causes free iron release and lipid peroxidation deposition, and eventually leads to ferroptosis of osteoblasts. Importantly, the use of AMPK or ferroptosis inhibitors in vivo markedly reduced MC-LR-induced osteoblast death and impaired osteogenic differentiation. Interestingly, MC-LR exposure promotes iron uptake in bone marrow macrophages through the TF-TFR1 pathway, leading to its transformation to TRAP-positive pre-osteoclast cells, thereby promoting bone resorption. Overall, our data innovatively revealed the core mechanism of MC-LR-induced osteoporosis, providing the bi-directional regulation of MC-LR on osteoblast-osteoclast from the perspective of iron homeostasis imbalance.

Comparative Metabolomics Study of Four Kinds of Xihu Longjing Tea Based on Machine Fixing and Manual Fixing Methods

China Xihu Longjing tea is famous for its good flavor and quality. However, information on its related metabolites, except for flavonoids, is largely deficient. Different processing methods for China Xihu Longjing tea fixing-by machines at both the first and second step (A1), first step by machine and second step by hand (A2), first step by hand and second step by machine (A3), and by hand at both the first and second step (A4)-were compared using a UHPLC-QE-MS-based metabolomics approach. Liquid chromatography-mass spectrometry was used to analyze the metabolic profiles of the processed samples. A total of 490 metabolites (3 alkaloids, 3 anthracenes, 15 benzene and substituted derivatives, 2 benzopyrans, 13 coumarins and derivatives, 128 flavonoids, 4 furanoid lignans, 16 glycosides and derivatives, 5 indoles and derivatives, 18 isocoumarins and derivatives, 4 chalcones and dihydrochalcones, 4 naphthopyrans, 3 nucleosides, 78 organic acids and derivatives, 55 organooxygen compounds, 5 phenols, 109 prenol lipids, 3 saccharolipids, 3 steroids and steroid derivatives, and 17 tannins) were identified. The different metabolic profiles were distinguished using PCA and OPLS-DA. There were differences in the types and contents of the metabolites, especially flavonoids, furanoid lignans, glycosides and derivatives, organic acids and derivatives, and organooxygen compounds. There was a positive correlation between flavonoid metabolism and amino acid metabolism. However, there was a negative correlation between flavonoid metabolism and amino acid metabolism, which had the same trend as prenol lipid metabolism and tannins. This study provides new valuable information regarding differences in the metabolite profile of China Xihu Longjing tea processed based on machine fixing and on manual fixing methods.