Caspase-1 is involved in the <i>S. aureus</i>-induced IL-1alpha and IL-1beta release in keratinocytes.

<p>Primary keratinocytes were left unstimulated (- SA) or were stimulated with <i>S. aureus</i> (+ SA) for a total of six hours. To investigate the influence of caspase-1 on IL-1alpha and IL-1beta expression the cells were co-treated with a caspase-1 inhibitor (Ac-YVAD-CMK, 30 μM). Gene expression of IL-1alpha (A) and IL-1beta (B) was measured by real-time PCR. Protein secretion of IL-1alpha (C) and IL-1beta (D) was determined by ELISA. To further assess the influence of caspase-1, cells were transfected with a caspase-1 specific siRNA or a non-silencing control siRNA. Gene expression of IL-1alpha (E) and IL-1beta (F) was measured by real-time PCR, protein secretion of IL-1alpha (G) and IL-1beta (H) was analysed by ELISA. To directly assess activation of caspase-1 cells were transfected with a caspase-1 luciferase reporter plasmid and proteolytic activity of caspase-1 was determined by analysis of luciferase activity (I). Data are means ± SEM (*p< 0.05, **p< 0.01, n.s. = not significant, Student`s <i>t</i>-test, n = 6 (A-H) and n = 5 (I)).