During
sepsis, systemic
inflammation is observed and is associated with
multiple organ failure. Activation of NF-κB is crucial for inducing
inflammation, which is controlled by degradation of inhibitor molecules (IκB). The ubiquitination
proteasome pathway is responsible for the regulation of
protein turnover. In this study, we hypothesized that administration of 4[4-(5-nitro-
furan-2-ylmethylene)-3, -dioxo-pyrazolidin-1-yl]-
benzoic acid ethyl
ester (PYR-41), an inhibitor of ubiquitination, could reduce
inflammation and organ injury in septic mice.
PYR-41 prevented the reduction of IκB
protein levels and inhibited release of
tumor necrosis factor (TNF)-α in mouse macrophage RAW264.7 cells at 4 h after
lipopolysaccharide stimulation dose-dependently. Male C57BL/6 mice were subjected to cecal
ligation and
puncture (CLP) to induce
sepsis.
PYR-41 (5 mg/kg) or
dimethyl sulfoxide in saline (vehicle) was injected intravenously immediately after CLP. At 20 h after CLP,
PYR-41 treatment significantly decreased serum levels of proinflammatory
cytokines (TNF-α,
interleukin [IL]-1β, and IL-6) and organ injury markers (
aspartate aminotransferase,
alanine aminotransferase, and
lactate dehydrogenase).
PYR-41 significantly improved microscopic structure, and reduced
myeloperoxidase activity, number of apoptotic cells and
caspase-3 degradation in the lungs of septic mice. The reduced
protein levels of IκB in the lungs after CLP were restored by
PYR-41 treatment.
PYR-41 inhibited the expression of
cytokines (IL-1β and IL-6),
chemokines (keratinocyte-derived
chemokine and
macrophage inflammatory protein 2), and inflammatory mediators (
cyclooxygenase-2 and
inducible nitric oxide synthase) in the lungs of septic mice. Importantly,
PYR-41 significantly increased 10-day survival in septic mice from 42% to 83%. Therefore, targeting ubiquitination by
PYR-41 to inhibit NF-κB activation may represent a potential strategy of
sepsis therapeutics.