Diesel Particles Are Taken Up by Alveolar Type II Tumor Cells and Alter Cytokines Secretion

Abstract

Diesel exhaust particles can reach the alveolar space and interact with alveolar type II cells. The authors investigated whether diesel exhaust particles lead to an internalization process and alter the production of proinflammatory cytokines, such as interleukin-8 and granulocyte macrophage-colony-stimulating factor by human alveolar type II cells. Cells from the human lung epithelial cell line A-549 were incubated with diesel exhaust particles or with inert particles for different periods of time. Phagocytosis was studied with electron microscopic analysis and flow cytometry. Cytokines were quantified in super-natants with enzyme-linked immunosorbent assay. Both diesel exhaust particles and inert particles were similarly engulfed by alveolar type II cells. Diesel exhaust particles induced a dose- and a time-dependent increase in granulocyte macrophage-colony-stimulating factor release and a transient inhibition of interleukin-8 release, but inert particles did not. Diesel exhaust particles were taken up by alveolar type II cells, and they altered cytokine production. Alveolar type II cells, therefore, may represent a target site for the deleterious effects of diesel exhaust particles.

Key Words:

• alveolar type II cells
• cytokines
• diesel exhaust particles
• endocytosis
• granulocyte macrophage-colony-stimulating factor
• inflammation
• interleukin-8
• pollution