Targeting caspase-1 by inhalation-therapy: effects of Ac-YVAD-CHO on IL-1β, IL-18 and downstream proinflammatory parameters as detected in rat endotoxaemia
We set out to investigate whether the nebulized and inhaled specific caspase-1 inhibitor Ac-YVAD-CHO has the potential to attenuate the pulmonary and systemic release of the caspase-1-dependent cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18) as well as their downstream enzymes iNOS and COX-2 in rat experimental endotoxaemia.
Design and setting
Controlled, randomized animal study in a university research facility.
Male Sprague–Dawley rats (n = 32) were randomly treated as follows: Inhaled Ac-YVAD-CHO was administered in eight rats at a inhaled total dosage of 5 mg and in eight rats at a inhaled total dose of 0.5 mg before infusion of lipopolysaccharide (LPS; 5 mg/kg, i.v.). Eight animals received LPS only. Eight animals served as controls without endotoxaemia.
Measurements and results
After 4 h of endotoxaemia, levels of IL-1β, IL-18 and TNF-α in plasma and bronchoalveolar fluid (BALF) were analyzed. Nitric oxide (NO) release from alveolar macrophages was measured by Griess assay. Amounts of iNOS protein in alveolar macrophages and COX-2 protein in lung homogenates were determined by Western blotting. Significant reductions in release of IL-1β (–58%, p < 0.05) and IL-18 (–51%, p < 0.05) in plasma and IL-1β (–59%, p < 0.05) in BALF were found in animals pretreated with inhaled caspase-1 inhibitor compared with animals without therapy. Expression of iNOS in alveolar macrophages and COX-2in lung tissue was concurrently decreased in the treatment groups compared with control animals.
Our data demonstrate that administration of the caspase-1 inhibitor Ac-YVAD-CHO by inhalation is able to reduce the pulmonary and systemic release of proinflammatory mediators in rat endotoxaemia. These results further underscore that inhalation may constitute an effective route of anti-inflammatory drug administration, beneficial in the clinical setting of ARDS.
KeywordsRat Lipopolysaccharide Interleukin-1β IL-1β Interleukin-18 IL-18 Aerosol therapy
The study was supported by grants from the August-Scheidel-Stiftung and the Heinrich- und Fritz-Riese-Stiftung, University of Frankfurt to K.A.B.
- 2.Andrews P, Azoulay E, Antonelli M, Brochard L, Brun-Buisson C, Dobb G, Fagon JY, Gerlach H, Groeneveld J, Mancebo J, Metnitz P, Nava S, Pugin J, Pinsky M, Radermacher P, Richard C, Tasker R, Vallet B (2005) Year in review in intensive care medicine, 2004. I. Respiratory failure, infection, and sepsis. Intensive Care Med 31:28–40CrossRefPubMedGoogle Scholar
- 11.Agouridakis P, Kyriakou D, Alexandrakis MG, Prekates A, Perisinakis K, Karkavitsas N, Bouros D (2002) The predictive role of serum and bronchoalveolar lavage cytokines and adhesion molecules for acute respiratory distress syndrome development and outcome. Respir Res 3:25CrossRefPubMedPubMedCentralGoogle Scholar
- 16.Li P, Allen H, Banerjee S, Franklin S, Herzog L, Johnston C, McDowell J, Paskind M, Rodman L, Salfeld J, Towne E, Tracey D, Wardwell S, Wei F-Y, Wong W, Kamen R, Seshadri T (1995) Mice deficient in IL-1 beta-converting enzyme are defective in production of mature IL-1 beta and resistant to endotoxic shock. Cell 80:401–411CrossRefPubMedGoogle Scholar
- 17.Joosten LA, Smeets RL, Koenders MI, van den Bersselaar LA, Helsen MM, Oppers-Walgreen B, Lubberts E, Iwakura Y, van de Loo FA, van den Berg WB (2004) Interleukin-18 promotes joint inflammation and induces interleukin-1-driven cartilage destruction. Am J Pathol 165:959–967CrossRefPubMedPubMedCentralGoogle Scholar
- 23.Nuttall ME, Nadeau DP, Fisher PW, Wang F, Keller PM, DeWolf WE Jr, Goldring MB, Badger AM, Lee D, Levy MA, Gowen M, Lark MW (2000) Inhibition of caspase-3-like activity prevents apoptosis while retaining functionality of human chondrocytes in vitro. J Orthop Res 18:356–363CrossRefPubMedGoogle Scholar
- 29.Andrews P, Azoulay E, Antonelli M, Brochard L, Brun-Buisson C, de Backer D, Dobb G, Fagon JY, Gerlach H, Groeneveld J, Mancebo J, Metnitz P, Nava S, Pugin J, Pinsky M, Radermacher P, Richard C, Tasker R (2006) Year in review in intensive care medicine. 2005. I. Acute respiratory failure and acute lung injury, ventilation, hemodynamics, education, renal failure. Intensive Care Med 32:207–216CrossRefPubMedGoogle Scholar
- 33.Fletcher DS, Agarwal L, Chapman KT, Chin J, Egger LA, Limjuco G, Luell S, MacIntyre DE, Peterson EP, Thornberry NA, Kostura MJ (1995) A synthetic inhibitor of interleukin-1 beta converting enzyme prevents endotoxin-induced interleukin-1 beta production in vitro and in vivo. J Interferon Cytokine Res 15:243–248CrossRefPubMedGoogle Scholar