LPS-mediated septic shock is augmented in ceramide synthase 2 null mice due to elevated activity of TNFα-converting enzyme

Tumor necrosis factor α (TNFα) is an inflammatory cytokine that plays an intimate role in septic shock. Injection of high levels of lipopolysaccharide induces septic shock and death in mice within 30 h, whereas ceramide synthase 2 (CerS2) null mice, defective in the synthesis of very-long acyl chain ceramides, die within ∼10 h. The augmented rate of death of CerS2 null mice is due to elevated levels of TNFα secretion as a result of enhanced activity of TNFα-converting enzyme (TACE). We discuss the relationship between the sphingolipid acyl chain length and TACE activity and the relevance of this data to septic shock.