Abstract
Background: Ambient fine particulate matter (PM2.5) has emerged as a critical environmental threat to ocular health; however, the underlying molecular mechanisms affecting the retinal pigment epithelium (RPE) remain largely uncharacterized. This study aimed to investigate transcriptomic alterations in RPE cells following PM2.5 exposure and to identify key regulatory pathways involved. Methods: Next-generation sequencing (NGS) was used to investigate differential gene expression in ARPE-19 cells upon PM2.5 exposure. Bioinformatic analyses, including pathway enrichment and gene set enrichment analysis (GSEA), were performed to identify affected signaling cascades. Functional assays-including cell viability, wound healing, and Transwell migration-were conducted to evaluate phenotypic changes. Quantitative RT-PCR (Reverse Transcription Polymerase Chain Reaction) and ELISA (Enzyme-Linked Immunosorbent Assay) validated gene expression and transforming growth factor-beta (TGF-β) secretion. TGF-β stimulation and receptor inhibition were applied to dissect pathway involvement. Results: Comprehensive analysis revealed substantial changes in gene expression profiles, with pathway enrichment highlighting the activation of cell migration-related pathways such as focal adhesion, regulation of actin cytoskeleton, extracellular matrix (ECM)-receptor interaction, tight junction, and adherens junction. Notably, the TGF-β, MAPK (Mitogen-Activated Protein Kinase), and PI3K/AKT (Phosphoinositide 3-Kinase / Protein Kinase B) pathways were significantly modulated. Functional assays showed that PM2.5 exposure enhanced ARPE-19 cell viability and migratory capacity. Among the differentially expressed genes, angiopoietin-like 4 (ANGPTL4) was markedly upregulated following PM2.5 stimulation. Pharmacological inhibition of TGF-β signaling abrogated PM2.5-induced ANGPTL4 expression, suggesting a pivotal role of the TGF-β pathway in mediating these effects. Conclusion: These findings demonstrate that PM2.5 induces transcriptomic reprogramming and activates the TGF-β signaling cascade in RPE cells, thereby enhancing cellular migration. Specifically, ANGPTL4 was identified as a key downstream effector of this pathway. This study provides novel insights into the molecular mechanisms by which air pollution contributes to retinal disease pathogenesis and suggests potential therapeutic targets for preventing PM2.5-induced retinal injury.