Abstract Background and Purpose Protein palmitoylation is involved in learning and memory, and in emotional disorders. Yet, the underlying mechanisms in these processes remain unclear. Herein, we describe that A‐kinase anchoring protein 150 (AKAP150) is essential and sufficient for depressive‐like behaviours in mice via a palmitoylation‐dependent mechanism. Experimental Approach Depressive‐like behaviours in mice were induced by chronic restraint stress (CRS) and chronic unpredictable mild stress (CUMS). Palmitoylated proteins in the basolateral amygdala (BLA) were assessed by an acyl‐biotin exchange assay. Genetic and pharmacological approaches were used to investigate the role of the DHHC2‐mediated AKAP150 palmitoylation signalling pathway in depressive‐like behaviours. Electrophysiological recording, western blotting and co‐immunoprecipitation were performed to define the mechanistic pathway. Key Results Chronic stress successfully induced depressive‐like behaviours in mice and enhanced AKAP150 palmitoylation in the BLA, and a palmitoylation inhibitor was enough to reverse these changes. Blocking the AKAP150‐PKA interaction with the peptide Ht‐31 abolished the CRS‐induced AKAP150 palmitoylation signalling pathway. DHHC2 expression and palmitoylation levels were both increased after chronic stress. DHHC2 knockdown prevented CRS‐induced depressive‐like behaviours, as well as attenuating AKAP150 signalling and synaptic transmission in the BLA in CRS‐treated mice. Conclusion and Implications These results delineate that DHHC2 modulates chronic stress‐induced depressive‐like behaviours and synaptic transmission in the BLA via the AKAP150 palmitoylation signalling pathway, and this pathway may be considered as a promising novel therapeutic target for major depressive disorder.
Under the double cropping system, berries usually showed significant quality variations in the summer and winter seasons. In the two-year/four-consecutive-season study, two table grapes of 'Muscat Hamburg' and 'Victoria' were investigated to determine the phenolic compounds in their berries. Different from those of the summer season, the berries in the winter season suffered no high-temperature stress since veraison to harvest in 2014 and 2015. The variations in the season temperatures led to a higher anthocyanin concentration in the winter season berries of 'Muscat Hamburg' grapes than that in the summer berries, while the summer season berries had higher proportions of acylated and methylated anthocyanins than those in the winter season berries. Similar to the anthocyanins, the winter season berries also had a higher flavonol concentration in both varieties. Transcriptome analysis showed that the upregulated genes involved in the flavonoid pathway in the winter season berries were agreed with the changes found in the metabolites. However, the influence of the growing seasons on the flavanols was not consistent in the two varieties, and the variations in VviLARs between the grapes of 'Muscat Hamburg' and 'Victoria' might be the cause. This research helped us better understand the double cropping system and how the climate factors affected the phenolic compounds in the double cropping system.
Type 2 diabetic osteoporosis (T2DOP) is a chronic bone metabolic disease. Compared with traditional menopausal osteoporosis, the long-term high glucose (HG) microenvironment increases patients' risk of fracture and osteonecrosis. We were accumulating evidence that implicated ferroptosis as a pivotal mechanism of glucolipotoxicity-mediated death of osteocytes and osteoblast, a novel form of programmed cell death resulting from uncontrolled lipid peroxidation depending on iron. Vitamin K2 (VK2), a fat-soluble vitamin, is clinically applied to prevent osteoporosis and improve coagulation. This study aimed to clarify the role and mechanism of VK2 in HG-mediated ferroptosis. We established the mouse T2DOP model by intraperitoneal injection of streptozotocin solution and a high-fat and high-sugar diet. We also cultured bone marrow mesenchymal stem cells (BMSCs) in HG to simulate the diabetic environment in vitro. Based on our data, VK2 inhibited HG-mediated bone loss and ferroptosis, the latter manifested by decreased levels of mitochondrial reactive oxygen species, lipid peroxidation, and malondialdehyde and increased glutathione in vitro. In addition, VK2 treatment was capable of restoring bone mass and strengthening the expression of SIRT1, GPX4, and osteogenic markers in the distal femurs. As for further mechanism exploration, we found that VK2 could activate AMPK/SIRT1 signaling, and knockdown of SIRT1 by siRNA prevented the VK2-mediated positive effect in HG-cultured BMSCs. Summarily, VK2 could ameliorate T2DOP through the activation of the AMPK/SIRT1 signaling pathway to inhibit ferroptosis.
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