Fig. 5

The PLXNC1 agonist SL4c-d suppresses caspase-11 activity and improves survival in polymicrobial sepsis. BMDMs from wild-type mice were transfected with the Sema-loop 4c-d peptide (SL4c-d)—a PLXNC1 ligand—prior to LPS priming and transfection to control caspase-11 activity. In the supernatant of cells pretreated with SL4c-d, A LDH release and the B levels of IL-1β, C IL-18, and D caspase-11 and of vehicle controls. In cell lysates, the expression of E caspase-1 (arrow points at cleaved caspase-1 p20), F caspase-11 (arrow points at 38 kDa), and G gasdermin D protein (arrow points at cleaved gasdermin D at 31 kDa) was decreased after SL4c-d treatment, while H ASC protein expression was unaffected. Polymicrobial midgrade sepsis was induced in mice by CLP, and the mice received a daily i.v. injection of SL4c-d bound to Arg9 to ensure intracellular peptide delivery. After 24 h, the levels of the cytokines I TNF-α and J IL-8 were measured in the peritoneal lavage fluid from SL4c-d-treated animals. The levels of K IL-1β and L caspase-11 in the peritoneal lavage fluid were also measured. M Survival time of mice receiving SL4c-d treatment or vehicle control during polymicrobial sepsis over the course of 96 h. (The data are presented as the means ± SEMs; n = 4–11 mice/group; Western blots, n = 3 mice/group; *p < 0.05; **p < 0.01 and ***p < 0.001 as indicated)