Profiling Distinctive Inflammatory and Redox Responses to Hydrogen Sulfide in Stretched and Stimulated Lung Cells

Hydrogen sulfide (H₂S) protects against stretch-induced lung injury. However, the impact of H₂S on individual cells or their crosstalk upon stretch remains unclear. Therefore, we addressed this issue in vitro using relevant lung cells. We have explored (i) the anti-inflammatory properties of H₂S on epithelial (A549 and BEAS-2B), macrophage (RAW264.7) and endothelial (HUVEC) cells subjected to cycling mechanical stretch; (ii) the intercellular transduction of inflammation by co-culturing epithelial cells and macrophages (A549 and RAW264.7); (iii) the effect of H₂S on neutrophils (Hoxb8) in transmigration (co-culture setup with HUVECs) and chemotaxis experiments. In stretched epithelial cells (A549, BEAS-2B), the release of interleukin-8 was not prevented by H₂S treatment. However, H₂S reduced macrophage inflammatory protein-2 (MIP-2) release from unstretched macrophages (RAW264.7) co-cultured with stretched epithelial cells. In stretched macrophages, H₂S prevented MIP-2 release by limiting nicotinamide adenine dinucleotide phosphate oxidase-derived superoxide radicals (ROS). In endothelial cells (HUVEC), H₂S inhibited interleukin-8 release and preserved endothelial integrity. In neutrophils (Hoxb8), H₂S limited MIP-2-induced transmigration through endothelial monolayers, ROS formation and their chemotactic movement. H₂S induces anti-inflammatory effects in a cell-type specific manner. H₂S limits stretch- and/or paracrine-induced inflammatory response in endothelial, macrophage, and neutrophil cells by maintaining redox homeostasis as underlying mechanism.