Distinct downstream pathways of caspase-11 in regulating apoptosis and cytokine maturation during septic shock response.

Caspase-11 is an essential mediator of septic shock response and caspase-11-deficient mice are resistant to LPS-induced shock. Here we report that LPS-induced caspase-11 regulates lymphocyte apoptosis by activating both caspase-3 and caspase-7. The activation of caspase-11 preceded that of caspase-1 and caspases-3/-7, and in the absence of caspase-11, the activation of caspases-3/-7 was significantly reduced. The early activation of caspases-3/-7 by caspase-11 was not affected by blocking of caspase-1 activity and IL-1beta release, implying that caspase-11 activates caspases-3/-7 independently of caspase-1 activation. Furthermore, we show that caspase-11-mediated apoptosis under septic condition is Bid-independent. Our work suggests that the human homologue of caspase-11 may be an effective therapeutic target for treatment of septic shock.