Transcriptomic Changes in Human Pulmonary Fibroblasts Following Microplastics Exposure
To assess the cellular effects of polystyrene (PS) micro- and nanoparticles, human pulmonary fibroblasts (HPFs) were exposed to spherical PS particles of two diameters (100 nm and 1 µm) across multiple concentrations. For 100 nm particles, the concentrations were 0.1 g/L (A), 0.01 g/L (B), and 0.001 g/L (C); for 1 µm particles, 0.1 g/L (A), 0.05 g/L (D), 0.01 g/L (B), and 0.001 g/L (C) were tested. In summary, our data show that both particle size and concentration critically influence the cellular response to microplastics. At low concentrations (0.001 g/L), smaller particles (100 nm) induced transcriptional activation of mitochondrial and biosynthetic genes, suggesting early metabolic adaptation. In contrast, high concentrations (0.1 g/L), particularly of larger particles (1 µm), led to suppression of metabolic, mitochondrial, and proteostatic pathways, indicating functional impairment and potential cellular stress. Overall design: HPFs were obtained from PromoCell GmbH (cat. no.: C-12360; Germany) and cultured in Dulbecco's Modified Eagle Medium (DMEM, High Glucose; Thermo Fisher Scientific, USA), supplemented with 10% fetal bovine serum (FBS; Thermo Fisher Scientific, USA) and an antibiotic-antimycotic solution containing penicillin (10,000 U/mL), streptomycin (10,000 µg/mL), and amphotericin B (25 µg/mL; Thermo Fisher Scientific, USA). Cells were maintained at 37°C in an atmosphere containing 5% CO2. To assess the cellular effects of PS micro- and nanoparticles, HPFs were exposed to spherical PS particles of two different diameters.  For the 100 nm particles, three concentrations were selected: 0.1 g/L (A), 0.01 g/L (B), and 0.001 g/L (C). For the 1 µm particles, four concentrations were included: 0.1 g/L (A), 0.01 g/L (B), 0.001 g/L (C) and 0.05 g/L (D) .