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Abstract Background Mitochondria is prone to oxidative damage by endogenous and exogenous sources of free radicals, including particulate matter (PM). Given the role of mitochondria in inflammatory disorders, such as asthma and chronic obstructive pulmonary disease, we hypothesized that supplementation of vitamin D may play a protective role in PM-induced mitochondrial oxidative damages of human bronchial epithelial BEAS-2B cells. Methods BEAS-2B cells were pretreated with 1,25(OH)2D3, an active form of vitamin D, for 1 h prior to 24-hour exposure to PM (SRM-1648a). Oxidative stress was measured by flow cytometry. Mitochondrial functions including mitochondrial membrane potential, ATP levels, and mitochondrial DNA copy number were analyzed. Additionally, mitochondrial ultrastructure was examined using transmission electron microscopy. Intracellular and mitochondrial calcium concentration changes were assessed using flow cytometry based on the expression of Fluo-4 AM and Rhod-2 AM, respectively. Pro-inflammatory cytokines, including IL-6 and MCP-1, were quantified using ELISA. The expression levels of antioxidants, including SOD1, SOD2, CAT, GSH, and NADPH, were determined. Results Our findings first showed that 24-hour exposure to PM led to the overproduction of reactive oxygen species (ROS) derived from mitochondria. PM-induced mitochondrial oxidation resulted in intracellular calcium accumulation, particularly within mitochondria, and alterations in mitochondrial morphology and functions. These changes included loss of mitochondrial membrane integrity, disarrayed cristae, mitochondrial membrane depolarization, reduced ATP production, and increased mitochondrial DNA copy number. Consequently, PM-induced mitochondrial damage triggered the release of certain inflammatory cytokines, such as IL-6 and MCP-1. Similar to the actions of mitochondrial ROS inhibitor MitoTEMPO, 1,25(OH)2D3 conferred protective effects on mtDNA alterations, mitochondrial damages, calcium dyshomeostasis, thereby decreasing the release of certain inflammatory cytokines. We found that greater cellular level of 1,25(OH)2D3 upregulated the expression of enzymatic (SOD1, SOD2, and CAT) and non-enzymatic (GSH and NADPH) antioxidants to modulate cellular redox homeostasis. Conclusion Our study provides new evidence that 1,25(OH)2D3 acts as an antioxidant, enhancing BEAS-2B antioxidant responses to regulate mitochondrial ROS homeostasis and mitochondrial function, thereby enhancing epithelial defense against air pollution exposure.

Exposure to environmental metals has been associated with health outcomes including respiratory health. Little is known about the impact of exposure to environmental metals on lung function among young children in general population. This study aimed to investigate the associations of exposure to metals with lung function among young children in a population-based cohort. A total of 1488 children aged 5–8 years attended a follow-up visit as part of the Longitudinal Investigation of Global Health in Taiwanese Schoolchildren (LIGHTS) cohort. We measured urinary samples of vanadium (median: 1.21 ng/mL; interquartile range (IQR): 0.73–1.98), manganese (median: 0.23 ng/mL; IQR: 0.13–0.47), arsenic (median: 40.51 ng/mL; IQR: 21.66–70.49), nickel (median: 1.09 ng/mL; IQR: 0.31–3.60), and cadmium (median: 0.26 ng/mL; IQR: 0.11–0.43) and performed lung function tests. Urinary vanadium concentrations were inversely associated with FVC (β coefficient for the highest quartile versus the other quartiles: −33.40, p = 0.001), FEV1 (β: −41.31, p

Exposure to particulate matter (PM) has been associated with DNA damage, but the relationships between PM, telomere length and cellular senescence remain unclear. This study aimed to investigate the effects and potential mechanisms of PM on telomere length and cellular senescence in human lung epithelial cells. Human lung epithelial A549 cells were exposed to PM for 24 h. Cell viability and cytotoxicity were measured by the WST-1 assay and the lactate dehydrogenase release, respectively. Cellular uptake of PM was observed using transmission electron microscopy. Telomere length was measured using qPCR and expressed as T/S ratio. Cell cycle progression was analyzed by flow cytometry. Expression of human telomerase reverse transcriptase (hTERT) and cell cycle regulators was measured using mRNA by qPCR and protein levels by Western blot. Cellular senescence was determined by the expression of senescence-associated β-galactosidase (SA-β-Gal) with fluorescent microscopy and flow cytometry. Exposed to PM at the concentration of 200 μg/ml decreased cell viability and increased LDH levels in culture medium. Remarkably increased uptake of PM, shortening of telomere length, induction of G0/G1 phase arrest, and increased expression of senescence hallmarks were observed after exposure to PM in A549 cells. PM exposure induced upregulation of p21 and downregulation of proliferating cell nuclear antigen (PCNA) and hTERT expression, but no significant change in p53 expression, in A549 cells. Overall, exposure to PM may downregulate hTERT and PCNA through p53-independent induction of p21 expression, leading to telomere shortening, G0/G1 arrest and the onset of cellular senescence in human lung epithelial cells.

Background/purpose: Dengue disease is widespread in tropical and sub-tropical regions. Severe dengue infection is characterized by plasma leakage, fluid accumulation, severe bleeding, or vital organ impairment. Bleeding is a critical complication of dengue disease. However, the biomarkers of dengue disease are still unknown. Macrophages have a distinct polarization phenotype related to M1/M2 classification. Macrophage polarization toward the pro-inflammatory M1 phenotype is considered critical for efficient antiviral immune responses, whereas the anti-inflammatory M2 phenotype is considered essential for tissue remodeling. We investigated macrophage polarization patterns in the peripheral blood of pediatric patients with dengue disease. Methods: Medical records and laboratory data were collected from 23 pediatric healthy controls and 100 dengue disease samples from 50 dengue patients. Macrophage polarization-related surface markers were assessed using flow cytometry. Results: The percentage of macrophages in the peripheral blood was higher in dengue patients than in the healthy controls. The percentages of M2a and M2c macrophage subsets were higher and the percentage of M1 macrophage subset was lower in dengue patients than in healthy controls. However, the percentages of M1, M2a and M2b macrophage subsets in dengue patients with bleeding tendency were lower than that without bleeding tendency. The percentages of M2a, M2b, and M2c macrophage subsets were positively correlated with platelet counts. Conclusion: Decreased the percentages of M2 macrophage subsets in pediatric dengue patients are associated with bleeding tendency and lower platelet counts. Keywords: Pediatric dengue, Macrophage polarization, Bleeding, Platelet counts

Abstract Background Macrophage heterogeneity is the main feature of the tumour microenvironment. Breast cancer is one of the most life-threatening cancers. However, macrophage polarization patterns in different tumour stages and the importance of its relationship to human epidermal growth factor receptor 2 (HER2) in breast cancer remains highly unclear. The present study investigated the patterns of monocyte differentiation and macrophage polarization in breast cancer. Methods Patients with breast cancer (n = 48) and healthy controls (n = 39) were prospectively recruited. The percentages and subsets of circulating macrophage-like cells were analysed by flow cytometry, and the polarization patterns of these cells in the peripheral blood of patients with breast cancer were compared with those of healthy controls. In addition, macrophage polarization patterns in different stages and HER2 status in breast cancer were investigated. Results The percentages of circulating macrophages, which are defined as PM-2 K+ cells in the peripheral blood, were significantly higher in patients with breast cancer than in healthy controls. The percentages of M1-like macrophages were significantly lower, but those of M2-like macrophages were significantly higher in patients with breast cancer than in healthy controls. The percentage of M2c-like macrophages was significantly higher in advanced (stages II and III) breast cancer. However, the patterns of macrophage polarization were not associated with HER2 status in breast cancer. Conclusions Aberrant macrophage polarization was observed in breast cancer and was correlated with breast cancer stage. These quantitative data may provide new molecular biomarkers and potential therapeutic targets in breast cancer.

Acute exacerbations (AEs) of chronic hepatitis B (CH-B) are accompanied by increased T cell responses to hepatitis B core and e antigens (HBcAg/HBeAg). Why patients are immunotolerant (IT) to the virus and why AEs occur spontaneously on the immunoactive phase remain unclear. The role of HBcAg-specific CD4+CD25+ regulatory T (Treg) cells in AE and IT phases was investigated in this study. The SYFPEITHI scoring system was employed to predict MHC class II-restricted epitope peptides on HBcAg overlapping with HBeAg that were used for Treg-cell cloning and for the construction of MHC class II tetramers to measure Treg cell frequencies (Treg f). The results showed that HBcAg-specific Treg f declined during AE accompanied by increased HBcAg peptide-specific cytotoxic T lymphocyte frequencies. Predominant Foxp3-expressing Treg cell clones were generated from patients on the immune tolerance phase, while the majority of Th1 clones were obtained from patients on the immunoactive phase. Treg cells from liver and peripheral blood of CH-B patients express CD152 and PD1 antigens that exhibit suppression on PBMCs proliferation to HBcAg. These data suggest that HBcAg peptide-specific Treg cells modulate the IT phase, and that their decline may account for the spontaneous AEs on the natural history of chronic hepatitis B virus infection. [ABSTRACT FROM AUTHOR]