Defining the in vivo mechanism of air pollutant toxicity using murine stress response biomarkers

In Vitro Exposure of A549 and J774A.1 Cells to SiO2 and TiO2 Nanoforms and Related Cellular- and Molecular-Level Effects: Application of Proteomics

There is an emerging interest in incorporating proteomic data for environmental health risk assessments. Meanwhile, the production and use of engineered nanomaterials (ENMs) with attractive physicochemical properties are expanding with the potential for exposure, thus necessitating toxicity information on these materials for health risk analysis, where proteomic data can be informative. Here, cells (A549 human lung epithelial and J774A.1 mouse monocyte/macrophage cells) were exposed to ENMs (nanoforms of SiO2and TiO2) of different sizes and surface chemistries (dose: 0-100 μg/cm2, 24 h) for in vitro toxicity data. Cytotoxicity (CTB, ATP, and LDH), oxidative stress (GSH oxidation), and proteomic analysis (MS- and antibody-based) were conducted post-nanoparticle (NP) exposure to determine the relative potency and identify perturbed cellular pathways. Dose-, nanoform-, and cell type-specific cytotoxicity changes were observed upon exposure to both nanoSiO2 and nanoTiO2. Size, agglomeration, surface modification, and metal impurities appeared to be the determinants of cytotoxicity. Proteomic analysis identified some enriched mechanistic pathways and biological processes relevant to cell defense/phagocytosis, stress, metabolism, apoptosis, and inflammatory processes in J774A.1 cells exposed to these NPs. A549 cells exhibited enriched pathway/biological processes relevant to transport/endocytosis, stress, metabolism, and inflammatory processes post-NP exposures. Concordance was observed between the nanoform exposure- and cell type-related cytotoxicity responses, notably cellular ATP, which is critical for cell viability, oxidative stress, and cellular pathways/biological processes. These findings demonstrate the application of proteomics in regulatory toxicology and warrant further research in this direction.

Air pollution exposure and prevalence of non-alcoholic fatty liver disease and related cirrhosis: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

A systematic review and meta-analysis were used to investigate the relationship between air pollution exposure and the prevalence of non-alcoholic fatty liver disease (NAFLD) and its related cirrhosis. Through this study, we hope to clarify the potential public health risks of air pollution as an environmental exposure factor.

METHODS

Through a comprehensive and systematic search of the EMBASE, PubMed, Web of Science, and Cochrane library databases, studies published up to March 30, 2024, that met the eligibility criteria were identified. The meta-analysis aimed to determine the association between air pollution exposure and NAFLD risk. Subgroup analyses were conducted based on regional economic development after adjusting for confounding factors. The combined odds ratio (OR) was calculated, publication bias was assessed using funnel plots, and consideration was given to heterogeneity among study-specific relative risks.

RESULTS

This review included 14 observational studies (including 7 cohort studies and 7 cross-sectional studies) involving 43,475,41 participants. The pooled analysis showed that PM2.5, NOx, PM10, PM2.5-10, passive smoking, PM1, and air pollution from solid fuels were positively associated with the incidence and prevalence of NAFLD and its related cirrhosis. The risk ratios for PM2.5, NOx, PM10, PM2.5-10, passive smoking, and air pollution from solid fuels for NAFLD and its related cirrhosis were 1.33 (95 % CI: 1.25, 1.42), 1.19 (95 % CI: 1.14, 1.23), 1.27 (95 % CI: 1.05, 1.55), 1.05 (95 % CI: 1.00, 1.11), 1.53 (95 % CI: 1.12, 2.09), 1.50 (95 % CI: 0.86, 2.63), and 1.18 (95 % CI: 0.85, 1.63), respectively. In contrast, the risk ratio for O3 was 0.75 (95 % CI: 0.69, 0.83), suggesting that O3 may lower the incidence and prevalence of NAFLD and its related cirrhosis. We also conducted subgroup analyses based on the level of national development to examine the impact of PM2.5 on NAFLD and its related cirrhosis. The results showed that the risk of NAFLD and its related cirrhosis associated with PM2.5 in developing countries was 1.41 (95 % CI: 1.29, 1.53), which was higher than 1.20 (95 % CI: 1.12, 1.29) in developed countries.

CONCLUSION

The study findings show that PM2.5, NOx, PM10, PM2.5-10, passive smoking, PM1, and air pollution from solid fuels can increase an individual's risk of developing NAFLD and its related cirrhosis; while O3 can reduce the risk. In developing countries, the risk level of NAFLD and its related cirrhosis due to PM2.5 is higher than that in developed countries.

Coniferyl ferulate alleviate xylene-caused hematopoietic stem and progenitor cell toxicity by Mgst2

Xylene exposure is known to induce toxicity in hematopoietic stem and progenitor cells (HSPCs), leading to bone marrow suppression and potential leukemogenesis. However, research on the gene expression profiles associated with xylene-induced toxicity in HSPCs, and effective therapeutic interventions, remains scarce. In our study, we employed single-cell RNA sequencing to capture the transcriptomic shifts within bone marrow HSPCs both prior to and following treatment with coniferyl ferulate (CF) in a mouse model of xylene-induced hematotoxicity. Subsequently, we pinpointed CF as a targeted agent using SPR-LC/MS analysis. This enabled us to confirm the link between the gene Mgst2 and specific cellular subtypes. Our data revealed that CF significantly countered the reduction of both monocyte and neutrophil progenitor cells, which are commonly affected by xylene toxicity. Through targeted analysis, we identified Mgst2 as a direct molecular target of CF. Notably, Mgst2 is preferentially expressed in neutrophil progenitor cells and is implicated in mitochondrial metabolic processes. By selectively inhibiting Mgst2 in bone marrow, we observed amelioration of xylene-induced hematotoxic effects. In summary, our findings suggest that coniferyl ferulate can mitigate the detrimental impact of xylene on hematopoietic stem and progenitor cells by targeting Mgst2, particularly within subpopulations of neutrophil progenitors. This discovery not only advances our comprehension of the cellular response of HSPCs to xenobiotic stressors like xylene but also identifies CF and Mgst2 as potential therapeutic targets for alleviating xylene-induced hematotoxicity.