PYCARD and colitis: Mechanistic studies showed that the severity of colitis induced by 10-nm particles was prevented when mice were deficient in apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain CARD (PYCARD gene, or ASC) (164), indicating that small SiO2 nanoparticles aggravate colitis through activation of the PYCARD inflammasome (163).