miR-9-5p regulates CCL5 mediated inflammatory responses in macrophages exposed to PM10

Exposure to particulate matter (PM) is associated with heightened inflammatory responses in macrophages, contributing to the development of respiratory diseases and modulation of the tumor microenvironment. While miR-9-5p has been implicated in various inflammatory pathways, its role in regulating C-C chemokine ligand 5 (CCL5) expression under PM exposure remains unclear. In this study, we investigated the effects of PM₁₀ and PM_2.5 on miR-9-5p expression and its potential association with CCL5 expression regulation in macrophages. PM₁₀ exposure significantly upregulated miR-9-5p expression, accompanied by increased CCL5 expression at both mRNA and protein levels. Notably, miR-9-5p knockdown led to a partial reduction in PM₁₀-induced CCL5 expression, suggesting a potential regulatory interaction. Additionally, PM exposure activated the AKT and MAPK signaling pathways, which may contribute to the observed inflammatory response. These findings suggest that miR-9-5p modulates CCL5 expression in response to PM₁₀, although further studies are needed to clarify the underlying mechanisms. These results provide new insights into the complex inflammatory responses triggered by PM exposure and highlight miR-9-5p as a potential target for further investigation in PM-associated diseases.