Difference in the cellular response following THP-1 derived phagocytic monocyte cells exposure to commercial aluminum-based adjuvants and aluminum-containing vaccines.

BACKGROUND: Aluminum-based adjuvants (ABAs) enhance the immune response following vaccine injection. Their mechanisms of action are not fully understood, and their bio-persistency have been described associated with long-term adverse effects. METHODS: We evaluated and compared the cellular effects of the two main ABAs and whole vaccines on ATP production, ROS generation and cytokines production (IL-6 and IL-10), using THP-1 cells. RESULTS: ABAs altered the cell energy metabolism by increasing ROS production after 24 h and reducing ATP production after 48 h. In addition, both ABAs and whole vaccines induced different kinetics of IL-6 production, whereas only ABAs induced IL-10 secretion. CONCLUSION: This study showed clearly, for a first time, a difference in cellular response to the ABAs and whole vaccines which should be taken into consideration in future studies focusing on the effect of ABA in vaccines. Future studies on ABAs should also pay attention to mitochondrial function alterations following exposure to ABA-containing vaccines.

The relationship between residential exposure to atmospheric pollution and circulating miRNA in adults living in an urban area in northern France.

INTRODUCTION: MicroRNAs are epigenetic regulatory factors capable of silencing the expression of target genes and might mediate the effects of air pollution on health. The objective of the present population-based study was to investigate the association between microRNA expression and long-term, residential exposure to atmospheric PM10 and NO2. METHOD: We included 998 non-smoking adult participants from the cross-sectional ELISABET survey (2010-2014) in the Lille urban area of France. The mean residential annual pollution levels were estimated with an atmospheric dispersion modelling system. Ten microRNAs were selected on the basis of the literature data, together with two housekeeping microRNAs (miR-93-5p and miR-191-5p) and were quantified with RT-qPCRs. Multivariate linear regression models were used to study the association between microRNAs and air pollution. The threshold for statistical significance (after correction for the FDR) was set to p < 0.1. RESULTS: The mean annual exposure between 2011 and the year of inclusion was 26.4 ± 2.0 µg/m3 for PM10 and 24.7 ± 5.1 µg/m3 for NO2. Each 2 µg/m3 increment in PM10 exposure was associated with an 8.6% increment (95%CI [3.1; 14.3]; pFDR = 0.019) in miR-451a expression. A 5 µg/m3 increment in NO2 exposure was associated with a 5.3% increment ([0.7; 10]; pFDR = 0.056) in miR451a expression, a 3.6% decrement (95%CI [-6.1; -1.1]; pFDR = 0.052) in miR-223-3p expression, a 3.8% decrement (95%CI[-6.8; -0.7]; pFDR = 0.079) in miR-28-3p expression, a 4.3% decrement (95%CI [-7.7; -0.8]; pFDR = 0.055) in miR-146a-5p expression, and a 4.0% decrement (95% CI[-7.4; -0.4]; pFDR = 0.059) in miR-23a-5p expression. The difference between the two housekeeping microRNAs miR-93-5p and miR-191-5p was also associated with PM10 and NO2 exposure. CONCLUSION: Our results suggest that circulating miRNAs are potentially valuable biomarkers of the effects of air pollution.

Short-term and residential exposure to air pollution: Associations with inflammatory biomarker levels in adults living in northern France.

INTRODUCTION: Air pollution has an impact on health, and low-grade inflammation might be one of the underlying mechanisms. The objective of the present study of adults from northern France was to assess the associations between short-term and residential exposure to air pollution and levels of various inflammatory biomarkers. METHODS: The cross-sectional Enquête Littoral Souffle Air Biologie Environnement (ELISABET) study was conducted from 2011 to 2013 in the Lille and Dunkirk urban areas of northern France. Here, we evaluated the associations between PM10, NO2 and O3 exposure (on the day of the blood sample collection and on the day before, and the mean annual residential level) and levels of the inflammatory biomarkers high-sensitivity C-reactive protein (hsCRP), interleukin (IL)-1ß, IL-6, IL-8, IL-10, IL-17A, IL-22, and tumor necrosis factor α. RESULTS: We assessed 3074 participants for the association with hsCRP and a subsample of 982 non-smokers from Lille for the association with plasma cytokine levels. A 10 µg/m3 increment in PM10 and NO2 levels on the day of sample collection and on the day before was associated with a higher hsCRP concentration (3.43% [0.68; 6.25] and 1.75% [-1.96; 5.61], respectively, whereas a 10 µg/m3 increment in O3 was associated with lower hsCRP concentration (-1.2% [-3.95; 1.64]). The associations between mean annual exposure and the hsCRP level were not significant. Likewise, the associations between exposure and plasma cytokine levels were not statistically significant. CONCLUSION: Short-term exposure to air pollution was associated with higher serum hsCRP levels in adult residents of two urban areas in northern France. Our results suggest that along with other factors, low-grade inflammation might explain the harmful effects of air pollution on health.

Adipocyte-induced transdifferentiation of osteoblasts and its potential role in age-related bone loss.

Our preliminary findings have lead us to propose bone marrow adipocyte secretions as new contributors to bone loss. Indeed, using a coculture model based on human bone marrow stromal cells, we previously showed that soluble factors secreted by adipocytes induced the conversion of osteoblasts towards an adipocyte-like phenotype. In this study, microarray gene expression profiling showed profound transcriptomic changes in osteoblasts following coculture and confirmed the enrichment of the adipocyte gene signature. Double immunofluorescence microscopic analyses demonstrated the coexpression of adipogenic and osteoblastic specific markers in individual cells, providing evidence for a transdifferentiation event. At the molecular level, this conversion was associated with upregulated expression levels of reprogramming genes and a decrease in the DNA methylation level. In line with these in vitro results, preliminary immunohistochemical analysis of bone sections revealed adipogenic marker expression in osteoblasts from elderly subjects. Altogether, these data suggest that osteoblast transdifferentiation could contribute to decreased bone mass upon ageing.

Toxicological appraisal of the chemical fractions of ambient fine (PM2.5-0.3) and quasi-ultrafine (PM0.3) particles in human bronchial epithelial BEAS-2B cells.

New toxicological research is still urgently needed to improve the current knowledge about the induction of some underlying mechanisms of toxicity by the different chemical fractions of ambient particulate matter (PM). This in vitro study sought also to better evaluate and compare the respective toxicities of fine particles (PM2.5-0.3) and their inorganic and organic chemical fractions, and the respective toxicities of the organic chemical fractions of PM2.5-0.3 and quasi-ultrafine particles (PM0.3). Human bronchial epithelial BEAS-2B cells were also exposed for 6-48 h to relatively low doses of PM2.5-0.3 and their organic extractable (OEM2.5-0.3) and non-extractable (NEM2.5-0.3) fractions, and the organic extractable fraction (OEM0.3) of PM0.3. We reported that not only PM2.5-0.3, but also, to a lesser extent, its inorganic chemical fraction, NEM2.5-0.3, and organic chemical fraction, OEM2.5-0.3, were able to significantly induce ROS overproduction and oxidative damage notwithstanding the early activation of NRF2 signaling pathway. Moreover, for any exposure, inflammatory and apoptotic events were noticed. Similar results were observed in BEAS-2B cells exposed to OEM0.3, rich of polycyclic aromatic hydrocarbons and their nitrated and oxygenated derivatives. In BEAS-2B cells exposed for 24 and 48 h to OEM2.5-0.3 and OEM0.3, to a higher extent, there was an alteration of the levels of some critical proteins even though crucial for the autophagy rather than a real reduction of autophagy. It is noteworthy that the toxicological effects were equal or mostly higher in BEAS-2B cells exposed for 6 and/or 24 h to PM2.5-0.3 from those exposed to NEM2.5-0.3 or OEM2.5-0.3, and in BEAS-2B cells exposed for 6 and/or mostly 24 h to OEM0.3 from those exposed to OEM2.5-0.3. Taken together, these results revealed the higher potentials for toxicity, closely linked to their respective physical and chemical characteristics, of PM2.5-0.3 vs NEM2.5-0.3 and/or OEM2.5-0.3, and OEM0.3 vs OEM2.5-0.3.

Variations of secretome profiles according to conditioned medium preparation: The example of human mesenchymal stem cell-derived adipocytes.

One challenging point in analyzing cellular secretome collected as conditioned medium is cross-contamination by cell culture media components, especially bovine serum proteins. A common approach for serum removal is to wash the cells, an alternative is to grow cells using serum-free conditions. Given that the sample processing may influence the phenotype of cells and thus the secretome, it is important to establish the optimal protocol for each cell type. In this study, we compared two methods for preparing conditioned medium from human adipocytes derived from mesenchymal stem cells. Cells were either washed twice with PBS or cultured the last four days of differentiation in serum-free adipogenic medium. Gene expression of the cells was evaluated by using real-time PCR and 1D LC-MS/MS was used to compare secreted proteins present in the culture supernatants. Surprisingly, results showed significant differences in gene expression patterns of the cells and in protein content of the conditioned media and suggested that PBS washes induced severe modifications of the phenotype of cells and thus changes in protein secretion profiles. These data emphasize the significant variations in protein species related to cell manipulations and underline the importance of procedure optimization prior to any proteomic investigation.