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Background: Mesenchymal stem cells (MSC) play important roles in modulating the activities of T lymphocytes, dendritic cells and natural killer cells. These immunoregulatory properties of MSC suggest their therapeutic potential in autoimmune diseases. However, the effects of MSC on B cells are still poorly understood. The present study was designed to investigate the interaction between MSC and B cells both in vitro and in vivo, and to determine the possible mechanism of action. Design and Method: The effect of human umbilical cord mesenchymal stem cells (UC-MSC) on proliferation and differentiation of B-cells were characterized in vitro, and we also tested the immunoregulatory properties of mouse bone marrow MSC (BM-MSC) on T cell dependent and independent antibody production in vivo in mice. Results: Treatment with human UC-MSC resulted in an increase of proliferation, differentiation of B cells into plasma cells and production of antibodies in vitro. Mouse BM-MSC significantly enhanced T cell dependent and independent antibodies production in vivo in mice. PGE2 partially mediated the immunosuppressive activity of human UC-MSC but IL-6 did not regulate this activity. Conclusion: MSC promote proliferation and differentiation of B cells in vitro and in vivo partially through PGE2 but not IL-6.

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Hypomyelination in the central nerves system (CNS) is one of the most obviously pathological features in Niemann-Pick Type C disease (NPC), which is a rare neurodegenerative disorder caused by mutations in the NPC intracellular cholesterol transporter 1 or 2 (Npc1 or Npc2). Npc1 plays key roles in both neurons and oligodendrocytes during myelination, however, the linkage between the disturbed cholesterol transport and inhibited myelination is unrevealed. In this study, mass spectrometry (MS)-based differential quantitative proteomics was applied to compare protein composition in the corpus callosum between wild type (WT) and NPC mice. In total, 3009 proteins from both samples were identified, including myelin structural proteins, neuronal proteins, and astrocyte-specific proteins. In line to hypomyelination, our data revealed downregulation of myelin structural and indispensable proteins in Npc1 mutant mice. Notably, the reduced ceramide synthase 2 (Cers2), UDP glycosyltransferase 8 (Ugt8), and glycolipid transfer protein (Gltp) indicate the altered sphingolipid metabolism in the disease and the involvement of Gltp in myelination. The identification of most reported myelin structural proteins and proteins from other cell types advocates the use of the corpus callosum to investigate proteins in different cell types that regulate myelination.Electronic supplementary materialThe online version of this article (10.1186/s13041-019-0440-9) contains supplementary material, which is available to authorized users.

BackgroundNAD+, nicotinamide adenine dinucleotide, is mostly described to associate with the aging process. We aimed to investigate the association between human whole blood NAD+ contents and aging in a relative large-scale community-based population and further to address the gender impact on this association.MethodsWe recruited 1,518 participants aged over 18 years old and free of cardiovascular and any type of cancer from the Jidong community from 2019 to 2020. Whole blood NAD+ level was measured by cycling assay and LC-mass spectroscopy assay. The chronological age and clinical data were collected using standard questionnaires. The participants were divided into five groups according to their chronological age. General liner regression model was performed to analyze the association between NAD+ contents and aging. In addition, we also conducted subgroup analysis by gender.ResultsThe mean age of included 1,518 participants was 43.0 years, and 52.6% of them were men. The average levels of whole blood NAD+ of total participants was 33.0 ± 5.5 μmol/L. The whole blood NAD+ contents in men were significantly higher than that in women (34.5 vs. 31.3 μmol/L). There was significant difference in the meat diet among NAD+ quartile groups (p = 0.01). We observed a decline trend of NAD+ contents with aging before 50 years in total participants with significant level in 40–49 years old group (β coefficients with 95% confidence interval (95% CI): −1.12 (−2.18, −0.06)), while this trend disappeared after the 50 years. In addition, this association was significantly altered by gender (p for interaction = 0.003). In men, as compared with ≤29 years group, adjusted β coefficient decreased with aging but was only significant in the ≥60 year group (β,−2.16; 95% CI, −4.16 to −0.15). In females, the level of whole blood NAD+ did not significantly differ among five age groups and without the trend as males.ConclusionsAssociation of whole blood NAD+ contents with aging significantly differed in males and females. The loss of blood NAD+ with aging only was observed in males, especially in the male middle-aged population. It is crucial to consider the gender difference in further NAD+ related studies in the future.

ObjectiveThe liver performs a central role in regulating energy homeostasis by increasing glucose output during fasting. Recent studies on Argonaute2 (Ago2), a key RNA-binding protein mediating the microRNA pathway, have illustrated its role in adaptive mechanisms according to changes in metabolic demand. Here we sought to characterize the functional role of Ago2 in the liver in the maintenance of systemic glucose homeostasis.MethodsWe first analyzed Ago2 expression in mouse primary hepatocyte cultures after modulating extracellular glucose concentrations and in the presence of activators or inhibitors of glucokinase activity. We then characterized a conditional loss-of-function mouse model of Ago2 in liver for alterations in systemic energy metabolism.ResultsHere we show that Ago2 expression in liver is directly correlated to extracellular glucose concentrations and that modulating glucokinase activity is adequate to affect hepatic Ago2 levels. Conditional deletion of Ago2 in liver resulted in decreased fasting glucose levels in addition to reducing hepatic glucose production. Moreover, loss of Ago2 promoted hepatic expression of AMP-activated protein kinase α1 (AMPKα1) by de-repressing its targeting by miR-148a, an abundant microRNA in the liver. Deletion of Ago2 from hyperglycemic, obese, and insulin-resistant Lepob/ob mice reduced both random and fasted blood glucose levels and body weight and improved insulin sensitivity.ConclusionsThese data illustrate a central role for Ago2 in the adaptive response of the liver to fasting. Ago2 mediates the suppression of AMPKα1 by miR-148a, thereby identifying a regulatory link between non-coding RNAs and a key stress regulator in the hepatocyte.

Previous studies have shown that microglia impact the proliferation and differentiation of neurons during hippocampal neurogenesis via the fractalkine/CX3 chemokine receptor 1 (CX3CR1) signaling pathway. However, whether microglia can influence the maturation and dendritic growth of newborn neurons during hippocampal neurogenesis remains unclear. In the present study, we found that the number of doublecortin-positive cells in the hippocampus was decreased, and the dendritic length and number of intersections in newborn neurons in the hippocampus were reduced in transgenic adult mice with CX3CR1 deficiency (CX3CR1GFP/GFP). Furthermore, after experimental seizures were induced with kainic acid in these CX3CR1-deficient mice, the expression of c-fos, a marker of neuronal activity, was reduced compared with wild-type mice. Collectively, the experimental findings indicate that the functional maturation of newborn neurons during hippocampal neurogenesis in adult mice is delayed by CX3CR1 deficiency.