The Role of Mcl-1 in S. aureus-Induced Cytoprotection of Infected Macrophages
Figure 7
The role of NFκB and IL-6 in cytoprotection induced by S. aureus. (a) Inhibition of S. aureus-induced cytoprotection upon treatment with an NFκB inhibitor was assessed by measuring caspase-3 activation. RAW 264.7 macrophages were pretreated for 30 min with Bay 11-7095 (4 μM) followed by bacterial infection at an MOI of 5 for 2 h. STS was added for an additional 3 h, and then caspase-3 activity was measured in cell lysates (as described in Section 2). Data represent mean SD caspase-3 activity (RFU/min) from three separate experiments. . (b, c) The influence of IL-6 on STS- (1 μM) or CHX- (10 μM) induced cytotoxicity in S. aureus-infected macrophages. (b) hMDMs were preincubated with anti-IL6 receptor antibodies (1 μg/mL) for 1 h followed by S. aureus infection at an MOI of 1 : 50 for 2. STS or CHX was added for 6 h, and then permeabilisation of the plasma membrane or cell lysis was determined by measuring LDH activity in conditioned media. Cell death after treatment with STS or CHX alone was set as 100%. Diagram shows the mean values calculated from the results of three independent experiments using hMDMs derived from different donors. Bars represent mean relative expression SD; ; NS: not significant. (c) RAW 264.7 cells were infected with S. aureus (MOI 1 : 5) or stimulated with conditioned medium collected from infected RAW 264.7 cells 5 h p.i. alone (cmed) or with anti-IL6 receptor (1 μg/mL) antibodies (cmed + anty-IL6R). At 2 h after stimulation, macrophages were treated with STS for another 4 h and then caspase-3 activity was measured. Caspase-3 activation induced by STS alone was set as 100%. Shown are mean values calculated from the results of three independent experiments. Bars represent mean relative expression SD; ; .
