Cryptococcus neoformans Secretes Small Molecules That Inhibit IL-1β Inflammasome-Dependent Secretion

Figure 6

ILA is partly responsible for the inhibitory activity of 1 kDa CM35. (a, b) Percentage of cytokine secretion, measured by IL-1β (a) release by BMMs stimulated with LPS+nigericin and the addition of possible inflammasome inhibitors (CM35, PLA, HPLA, and ILA). Positive group LPS+nigericin was normalized for a 100% cytokine secretion. The numbers below the bars represent the concentration of the respective metabolite in μM, except for 1 kDa CM35 and MM (10% ). The graph shows the metabolites alone, followed by double combinations and a triple combination of all metabolites. The bars represent three independent assays. (b, c) BMMs stimulated with LPS (500 ng/ml) and nigericin (20 μM) or Δcap67 (MOI 5 : 1), with or without inhibitors, were analyzed for caspase-1 activation (FLICA). 1 kDa CM35 = conditioned media from C. neoformans B3501; MM = minimal media; PLA = DL-3-Phenyllactic acid; HPLA = DL-p-Hydroxyphenyllactic acid; ILA = DL-Indole-3-lactic acid. Statistical analysis was made utilizing one-way ANOVA, where ns: not significant; ; ; . Comparisons were made with 1 kDa CM35 group. ns means that the inhibition level achieved by the metabolites is similar to the inhibition achieved by 1 kDa CM35 (a, b). Comparisons were made with the positive control (LPS+nigericin or LPS+Δcap67) (c, d).

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