[Caspase-1 inhibitor AC-YVAD-CMK blocks IL-1β secretion of bone marrow-derived macrophages induced by Acinetobacter...

Area of Science:

• Immunology
• Microbiology
• Pathology

Background:

• Acinetobacter baumannii (A. baumannii) infection triggers inflammatory responses, including the secretion of Interleukin-1 beta (IL-1β).
• Caspase-1 plays a critical role in the maturation and release of IL-1β, a key cytokine in inflammation.

Purpose of the Study:

• To investigate the effect of the caspase-1 selective inhibitor AC-YVAD-CMK on IL-1β secretion induced by A. baumannii.
• To evaluate the therapeutic potential of AC-YVAD-CMK in an A. baumannii-induced pneumonia model.

Main Methods:

• Bone marrow-derived macrophages (BMDMs) were stimulated with A. baumannii, and IL-1β levels in supernatant were measured by ELISA.
• Pro-IL-1β mRNA and protein expression were assessed using real-time quantitative PCR and Western blot.
• Caspase-1 activity was inhibited using AC-YVAD-CMK in vitro and in vivo models.
• Pulmonary pathology was evaluated in mice infected with A. baumannii and treated with AC-YVAD-CMK.

Main Results:

• A. baumannii stimulation dose-dependently increased IL-1β levels in macrophage culture supernatants.
• Pro-IL-1β mRNA and protein expression remained unchanged despite A. baumannii stimulation.
• AC-YVAD-CMK effectively blocked mature IL-1β secretion both in vitro and in vivo.
• AC-YVAD-CMK treatment significantly ameliorated lung damage in mice infected with A. baumannii.

Conclusions:

• AC-YVAD-CMK effectively inhibits caspase-1-mediated IL-1β secretion induced by A. baumannii.
• Targeting caspase-1 with AC-YVAD-CMK demonstrates therapeutic potential for mitigating A. baumannii-induced pulmonary inflammation and damage.