NLRP3 inflammasome activation by particles and fibers: implications for human hazard assessment

The NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome has been shown to be involved in the manifestation of adverse effects following exposure to occupational, dietary and environmental particulate matter. In this review, we summarize knowledge on NLRP3 inflammasome activation by particles and fibers in vitro and in vivo, outline dominant activation mechanisms and discuss the link to human diseases. While the association between NLRP3 activation and development of diseases is well established for occupational exposure to mineral dusts like asbestos and quartz, the health effects of low-level exposure to environmental particulate pollutants, such as micro- and nanoplastics, desert dust or novel nanocomposites remain to be unraveled. Based on the combined literature of well-studied and emerging particles, we emphasize the relevance of testing for NLRP3 activation in the hazard assessment of novel particulate materials.