Dexamethasone upregulates macrophage PIEZO1 via SGK1, suppressing inflammation and increasing ROS and apoptosis.

The side effects of high-dose dexamethasone in anti-infection include increased ROS production and immune cell apoptosis. Dexamethasone effectively activates serum/glucocorticoid-regulated kinase 1 (SGK1), which upregulates various ion channels by activating store-operated calcium entry (SOCE), leading to Ca2+ oscillations. PIEZO1 plays a crucial role in macrophages' immune activity and function, but whether dexamethasone can regulate PIEZO1 by enhancing SOCE via SGK1 activation remains unclear. The effects of dexamethasone were assessed in a mouse model of sepsis, and primary BMDMs and the RAW264.7 were treated with overexpression plasmids, siRNAs, or specific activators or inhibitors to examine the relationships between SGK1, SOCE, and PIEZO1. The functional and phenotypic changes of mouse and macrophage models were detected. The results indicate that high-dose dexamethasone upregulated SGK1 by activating the macrophage glucocorticoid receptor, which enhanced SOCE and subsequently activated PIEZO1. Activation of PIEZO1 resulted in Ca2+ influx and cytoskeletal remodelling. The increase in intracellular Ca2+ mediated by PIEZO1 further increased the activation of SGK1 and ORAI1/STIM1, leading to intracellular Ca2+ peaks. In the context of inflammation, activation of PIEZO1 suppressed the activation of TLR4/NFκB p65 in macrophages. In RAW264.7 cells, PIEZO1 continuous activation inhibited the change in mitochondrial membrane potential, accelerated ROS accumulation, and induced autophagic damage and cell apoptosis in the late stage. CaMK2α was identified as a downstream mediator of TLR4 and PIEZO1, facilitating high-dose dexamethasone-induced macrophage immunosuppression and apoptosis. PIEZO1 is a new glucocorticoid target to regulate macrophage function and activity. This study provides a theoretical basis for the rational use of dexamethasone.

LncRNA-mRNA Expression Profiles and Functional Networks Associated with Cognitive Impairment in Folate-deficient Mice.

BACKGROUND: Cognitive impairment is a common neurocognitive disorder that affects the health of millions of people worldwide, related to folate deficiency. OBJECTIVE: The present study aimed to investigate the lncRNA-mRNA functional networks associated with cognitive impairment in folate-deficient mice and elucidate their possible molecular mechanisms. METHODS: We downloaded the gene expression profile (GSE148126) of lncRNAs and mRNAs from NCBI Gene Expression Omnibus (GEO) database. Four groups of mouse hippocampi were analyzed, including 4 months (4mo) and 18 months (18mo) of folic acid (FA) deficiency/supplementation. The differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) were identified using gplots and heatmap packages. The functions of the DEmRNAs were evaluated using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The hub genes were identified by CytoHubba plugins of Cytoscape, and protein-protein interaction (PPI) network of deregulated mRNAs was performed using the STRING database. Finally, lncRNA-mRNA co-expression and competitive endogenous RNA (ceRNA) network analyses were constructed. RESULTS: In total, we screened 67 lncRNAs with 211 mRNAs, and 89 lncRNAs with 229 mRNAs were differentially expressed in 4mo_FA and 18mo_FA deficient mice, respectively. GO analyses indicated that DEmRNAs were highly related to terms involved in binding and biological regulation. KEGG pathway analyses demonstrated that these genes were significantly enriched for renin secretion, pancreatic secretion, and AMPK signaling pathways in the 18mo_FA deficiency group. Subsequently, the top 5 hub genes were screened from the PPI network, which may be key genes with the progression of folate deficiency. Upon the lncRNA-mRNA co-expression network analysis, we identified the top 10 lncRNAs having the maximum number of connections with related mRNAs. Finally, a ceRNA network was constructed for DE lncRNAs and DEmRNAs, and several pivotal miRNAs were predicted. CONCLUSIONS: This study identified the lncRNA-mRNA expression profiles and functional networks associated with cognitive impairment in folate-deficient mice by bioinformatics analysis, which provided support for the possible mechanisms and therapy for this disease.