Myocardial contractile dysfunction in
sepsis is associated with the increased morbidity and mortality. Although the underlying mechanisms of the cardiac depression have not been fully elucidated, an exaggerated inflammatory response is believed to be responsible.
Nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3)
inflammasome is an intracellular platform that is involved in the maturation and release of
interleukin (IL)-1β. The aim of the present study is to evaluate whether
sepsis activates NLRP3
inflammasome/
caspase-1/IL-1β pathway in cardiac fibroblasts (CFs) and whether this
cytokine can subsequently impact the function of cardiomyocytes (cardiac fibroblast-myocyte cross-talk). We show that treatment of CFs with
lipopolysaccharide (LPS) induces upregulation of NLRP3, activation of caspase-1, as well as the maturation (activation) and release of IL-1β. In addition, the genetic (small interfering
ribonucleic acid [
siRNA]) and pharmacological (
glyburide) inhibition of the NLRP3
inflammasome in CFs can block this signaling pathway. Furthermore, the inhibition of the NLRP3
inflammasome in cardiac fibroblasts ameliorated the ability of LPS-challenged CFs to impact cardiomyocyte function as assessed by intracellular cyclic
adenosine monophosphate (cAMP) responses in cardiomyocytes. Salient features of this the NLP3
inflammasome/ caspase-1 pathway were confirmed in in vivo models of
endotoxemia/
sepsis. We found that inhibition of the NLRP3
inflammasome attenuated myocardial dysfunction in mice with LPS and increased the survival rate in mice with feces-induced
peritonitis. Our results indicate that the activation of the NLRP3
inflammasome in cardiac fibroblasts is pivotal in the induction of myocardial dysfunction in
sepsis.