NLRP3 Inflammasome and Host Protection against Bacterial Infection

The inflammasome is a multi-protein complex that induces maturation of inflammatory cytokines interleukin (IL)-1beta and IL-18 through activation of caspase-1. Several nucleotide binding oligomerization domain-like receptor family members, including NLRP3, recognize unique microbial and danger components and play a central role in inflammasome activation. The NLRP3 inflammasome is critical for maintenance of homeostasis against pathogenic infections. However, inflammasome activation acts as a double-edged sword for various bacterial infections. When the IL-1 family of cytokines is secreted excessively, they cause tissue damage and extensive inflammatory responses that are potentially hazardous for the host. Emerging evidence has shown that diverse bacterial pathogens or their components negatively regulate inflammasome activation to escape the immune response. In this review, we discuss the current knowledge of the roles and regulation of the NLRP3 inflammasome during bacterial infections. Activation and regulation of the NLRP3 inflammasome should be tightly controlled to prevent virulence and pathology during infections. Understanding the roles and regulatory mechanisms of the NLRP3 inflammasome is essential for developing potential treatment approaches against pathogenic infections.

Different Antiulcer Activities of Pantoprazole in Stress, Alcohol and Pylorus Ligation-Induced Ulcer Models / 한국실험동물학회지

Antiulcer effects of pantoprazole, a proton-pump inhibitor, on water-immersion restraint stress (WIRS)-, alcohol (ethanol)- and pylorus ligation-induced gastric ulcers were investigated in male rats. Rats were orally administered with pantoprazole 30 min prior to exposure to various types of ulcer inducers. In stress-induced ulcer model, rats were subjected to WIRS at 22degrees C for 4 hours, and the degree of ulcer (in mm) was evaluated. In alcohol-induced ulcer model, rats were orally administered with pure (100%) ethanol (1 mL/kg), and the ulcer lesions were measured 1 hour after ethanol challenge. In pylorus ligation-induced ulcer model, rats were subjected to pylorus ligation, and the degree of erosions and ulcers was scored 17 hours after the operation. Pantoprazole attenuated the ulcer lesions induced by WIRS in a dose-dependent manner, exhibiting a median effective dose (ED50) value of 0.78 mg/kg. By comparison, pantoprazole was effective at relatively-high doses for the improvement of ethanol-induced ulcers, showing an ED50 value of 20.5 mg/kg. Notably, pantoprazole was practically ineffective (ED50>50.0) in pylorus ligation model. Taken together, it was confirmed that pantoprazole showed inhibitory activity on gastric ulcers induced by stress and alcohol, but was ineffective on pylorus ligation-induced ulcer. Therefore, the results indicate that proton-pump inhibitors including pantoprazole might reveal highly-different effects according to the type of ulcer inducers, and that the prescription of antiulcer agents should be carefully selected.