Pharmacological Inhibition and Genetic Deletion of Cystathionine Gamma-Lyase in Mice Protects against Organ Injury in Sepsis: A Key Role of Adhesion Molecules on Endothelial Cells.

Hydrogen sulfide (H 2 S), synthesized by cystathionine gamma-lyase (Cth), contributes to the inflammatory response observed in sepsis. This study examines the effect of Cth-derived H 2 S in adhesion molecules on endothelial cells of vital organs in mice in a cecal ligation puncture (CLP)-induced model of sepsis, using two different and complementary approaches: Cth gene deletion and pharmacological inhibition. Our findings revealed a decreased level of H 2 S-synthesizing activity (via Cth) in both Cth -/- mice and PAG-treated wild-type (WT) mice following CLP-induced sepsis. Both treatment groups had reduced MPO activity and expression of chemokines (MCP-1 and MIP-2α), adhesion molecules (ICAM-1 and VCAM-1), ERK1/2 phosphorylation, and NF-κB in the liver and lung compared with in CLP-WT mice. Additionally, we found that PAG treatment in Cth -/- mice had no additional effect on the expression of ERK1/2 phosphorylation, NF-κB, or the production of chemokines and adhesion molecules in the liver and lung compared to Cth -/- mice following CLP-induced sepsis. The WT group with sepsis had an increased immunoreactivity of adhesion molecules on endothelial cells in the liver and lung than the WT sham-operated control. The Cth -/- , PAG-treated WT, and Cth -/- groups of mice showed decreased immunoreactivity of adhesion molecules on endothelial cells in the liver and lung following sepsis. Inhibition of H 2 S production via both approaches reduced adhesion molecule expression on endothelial cells and reduced liver and lung injury in mice with sepsis. In conclusion, this study demonstrates that H 2 S has an important role in the pathogenesis of sepsis and validates PAG use as a suited tool for investigating the Cth/H 2 S-signalling axis in sepsis.