Physico-chemically different carbon nanomaterials may elicit similar inflammatory molecular pathways within the lungs of mice

Carbon nanomaterials (CNMs) are an integral part of everyday life and their inhalation may cause serious health issues. A transcriptomic lung meta-analysis of five structurally and functionally distinct CNMs was conducted, with the aim of determining whether these CNMs participate in the same or different inflammatory molecular pathways. Treatment data were obtained from publicly available datasets from the GEO database. Two doses (0 and 18 μg/mouse) and two time points (1st and 28th day following the exposure) were analysed. A linear model was used to calculate Log2 fold change and unadjusted p values between each CNM-treated and control group based on a moderated t-test of the limma R package. The resulting differential expression data were used as input for the subsequent functional interpretation of individual contrasts and in meta-analysis by using iPathwayGuide software, with differential expression thresholds for absolute fold change were 0.6 and p-value 0.05. The analysis revealed that CNMs activate genes and molecular pathways associated with inflammation and two disorders appeared enriched: alpha-1-antitrypsin deficiency and chronic obstructive pulmonary disease. Overall, physico-chemically different CNMs can share some of the inflammatory pathways, and a single treatment with CNMs may have long-term implications.