ABSTRACT
UNLABELLED: After a major trauma, IL-1ß-producing capacity of monocytes is reduced. Generation of IL-1ß is important for appropriate immune response after trauma and requires not only synthesis and transcription of inflammasome components but also their activation. Altered IL-1ß-processing due to deregulated NLRP inflammasomes assembly is associated with several inflammatory diseases. However, the precise role of NLRP1 inflammasome in monocytes after trauma is unknown. Here, we investigated if NLRP1 inflammasome components are responsible for depressed monocyte function after trauma. We found in ex vivo in vitro assays that LPS-stimulation of CD14(+)-isolated monocytes from healthy volunteers (HV) results in remarkably higher capacity of the IL-1ß-release compared to trauma patients (TP). During the 10-day time course, this monocyte depression was highest immediately after admission. Inflammasome activation correlating with this inflammatory response was demonstrated by enhanced protein production of cleaved IL-1ß and caspase-1. Furthermore, we found that the gene expression of IL-1ß, caspase-1, and ASC was comparable in TP and HV after LPS-stimulation during the 10-day course, while NLRP1 was markedly reduced in TP. We demonstrated that transfected monocytes from TP, which expressed the lacking components, were recovered in their LPS-induced IL-1ß-release and that lacking of NLRP1 is responsible for the suppressed monocyte activity after trauma. The restoration of NLRP1 inflammasome suggests new mechanistic target for the recovery of dysbalanced immune reaction after trauma. KEY MESSAGE: Suppression in monocyte function occurs early after a major trauma or surgery. Reduced gene expression abrogates NLRP1 inflammasome assembly after trauma. Limited availability of inflammasome components may cause reduced host defense. Restoring NLRP1 in immune-suppressed monocytes recovers NLPR1 activity after trauma. Recovered inflammasome activity may improve the immune response to PAMPs/DAMPs.
Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Apoptosis Regulatory Proteins/metabolism , Inflammasomes/metabolism , Wounds and Injuries/metabolism , Adaptor Proteins, Signal Transducing/genetics , Adult , Apoptosis Regulatory Proteins/genetics , Case-Control Studies , Cytokines , Female , Gene Expression , Humans , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/metabolism , Lipopolysaccharide Receptors/metabolism , Lipopolysaccharides/immunology , Male , NLR Proteins , Severity of Illness Index , Wounds and Injuries/diagnosis , Wounds and Injuries/genetics , Wounds and Injuries/immunologyABSTRACT
BACKGROUND AND PURPOSE: Leukocyte migration into alveolar space plays a critical role in pulmonary inflammation resulting in lung injury. Acute ethanol (EtOH) exposure exerts anti-inflammatory effects. The clinical use of EtOH is critical due to its side effects. Here, we compared effects of EtOH and ethyl pyruvate (EtP) on neutrophil adhesion and activation of cultured alveolar epithelial cells (A549). EXPERIMENTAL APPROACH: Time course and dose-dependent release of interleukin- (IL-) 6 and IL-8 from A549 were measured after pretreatment of A549 with EtP (2.5-10 mM), sodium pyruvate (NaP, 10 mM), or EtOH (85-170 mM), and subsequent lipopolysaccharide or IL-1beta stimulation. Neutrophil adhesion to pretreated and stimulated A549 monolayers and CD54 surface expression were determined. KEY RESULTS: Treating A549 with EtOH or EtP reduced substantially the cytokine-induced release of IL-8 and IL-6. EtOH and EtP (but not NaP) reduced the adhesion of neutrophils to monolayers in a dose- and time-dependent fashion. CD54 expression on A549 decreased after EtOH or EtP treatment before IL-1beta stimulation. CONCLUSIONS AND IMPLICATIONS: EtP reduces secretory and adhesive potential of lung epithelial cells under inflammatory conditions. These findings suggest EtP as a potential treatment alternative that mimics the anti-inflammatory effects of EtOH in early inflammatory response in lungs.
