The Differential Effect of Carbon Dots on Gene Expression and DNA Methylation of Human Embryonic Lung Fibroblasts as a Function of Surface Charge and Dose

Abstract

<jats:p>This study presents a toxicological evaluation of two types of carbon dots (CD), similar in size (&lt;10 nm) but differing in surface charge. Whole-genome mRNA and miRNA expression (RNAseq), as well as gene-specific DNA methylation changes, were analyzed in human embryonic lung fibroblasts (HEL 12469) after 4 h and 24 h exposure to concentrations of 10 and 50 µg/mL (for positive charged CD; pCD) or 10 and 100 µg/mL (for negative charged CD, nCD). The results showed a distinct response for the tested nanomaterials (NMs). The exposure to pCD induced the expression of a substantially lower number of mRNAs than those to nCD, with few commonly differentially expressed genes between the two CDs. For both CDs, the number of deregulated mRNAs increased with the dose and exposure time. The pathway analysis revealed a deregulation of processes associated with immune response, tumorigenesis and cell cycle regulation, after exposure to pCD. For nCD treatment, pathways relating to cell proliferation, apoptosis, oxidative stress, gene expression, and cycle regulation were detected. The expression of miRNAs followed a similar pattern: more pronounced changes after nCD exposure and few commonly differentially expressed miRNAs between the two CDs. For both CDs the pathway analysis based on miRNA-mRNA interactions, showed a deregulation of cancer-related pathways, immune processes and processes involved in extracellular matrix interactions. DNA methylation was not affected by exposure to any of the two CDs. In summary, although the tested CDs induced distinct responses on the level of mRNA and miRNA expression, pathway analyses revealed a potential common biological impact of both NMs independent of their surface charge.</jats:p>

Carbon dots for virus detection and therapy

“…Genome-wide mRNA and miRNA expression (RNAseq) as well as gene-specific DNA methylation changes have been analyzed. Although some changes at the genomic level (deregulation of processes and pathways) were detected, the overall decrease in viability of the studied cells started from 100 μg mL −1 for positively charged CDs and for negatively charged CDs, the viability reached more than 90% even at a concentration of 500 μg mL −1 [60]. These results are similar to, for example, iron oxide nanoparticles, which are considered biocompatible nanoparticles.…”

Testing Strategies of the In Vitro Micronucleus Assay for the Genotoxicity Assessment of Nanomaterials in BEAS-2B Cells

“…Current evidence shows that exposure to NMs has numerous toxic effects in both prokaryotes and eukaryotes. In general, in vivo and in vitro studies in model systems suggest that NMs induce an inflammatory response, DNA damage, oxidative stress, lipid peroxidation, apoptosis, altered gene expression, cytotoxicity and reproductive toxicity [ 3 , 4 , 5 , 6 , 7 , 8 ]. Despite this fact, there is still a limited number of human biomonitoring studies focusing on the effects of NMs.…”

Combined In Vitro and In Vivo Approaches to Propose a Putative Adverse Outcome Pathway for Acute Lung Inflammation Induced by Nanoparticles: A Study on Carbon Dots

“…Indeed, Havrdova et al showed that poly(ethyleneimine)-based CDs exhibiting positive surface charge induced greater toxicity as compared to negative or neutral ones [ 29 ]. A recent toxicogenomics study conducted in human lung fibroblasts revealed also that positive CDs induced changes of immune response and cell cycle-related processes, contrary to negative ones [ 56 ].…”