Figure 6.

Schematic diagram showing the roles of thioredoxin-interacting protein (TXNIP)-inflammasome-caspase-1 in the clearance of bacteria from macrophages. Wild-type (WT) and Txnip knockout (KO) mouse macrophages demonstrate a similar engulfment of bacteria at the early stage of phagosome maturation. There is no difference in the levels of superoxide and the pH in phagosomes from WT and Txnip KO mouse macrophages. On the other hand, at the late stage of phagosome maturation, binding between TXNIP and NLRP3 induces the inflammasome complex to activate caspase-1, inhibiting the activity of NADPH oxidase, leading to a decrease in the pH of the phagosomal lumen. At this stage, there are significant differences in the levels of superoxide, the pH of the phagosomes, and the resultant clearance of bacteria in Txnip WT and KO macrophages.