Human and murine brain pericytes release selected cytokines upon S. pneumoniae challenge. Protein array analyses of cell-culture supernatants obtained from murine (A) and human (B) primary brain pericytes stimulated with S. pneumoniae (MOI = 40) or its vehicle for 6 h. The differentially expressed proteins are outlined with red rectangles, the positive controls with blue rectangles and the negative controls with green rectangles. IL-6 concentrations (determined by ELSA) in cell-culture supernatants of murine (blue bars; C) and human (red bars; D) primary brain pericytes 6 h after exposure to increasing concentrations of antibiotic-lysed serotype 2 S. pneumoniae (MOI = 2.5, 10, 40, 160). THY (= Todd–Hewitt broth supplemented with 0.2% yeast extract, used for culturing S. pneumoniae) and cell-culture medium served as negative controls. Effect of various anti-TLR antagonists (T2.5 = neutralizing antir-TLR2 antibody; TAK242 = a TLR4 antagonist; CQ = chloroquine = an endosomal TLR antagonist) and the NF-κB inhibitor parthenolide on S. pneumoniae (MOI = 40)-induced IL-6 release from murine (E) and human (F) primary brain pericytes. Response of human brain pericytes to conditioned media (green bars) from wild-type (WT), TLR2-deficient, ASC-deficient, and Nlrp3-deficient THP-1 cells stimulated with either THY or S. pneumoniae (MOI = 80; G). Response of human brain pericytes to conditioned media from S. pneumoniae-stimulated WT THP-1 treated either with the caspase-1 inhibitor VX-765, the Nlrp3 inhibitor MCC950, or its vehicles (DMSO or PBS, H). Data are given as individual values as well as means ± SD. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, using ANOVA with Tukey’s multiple comparisons test
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